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Distribution authorized to U.S. Gov't. agenciesonly; Administrative/Operational Use; APR 1971.Other requests shall be referred to Army

Materiel Command, Alexandria, VA.

AMC ltr, 13 Aug 1971

8/11/2019 884519


7ö £ - £ j>

AMCP-706-123

A M C A M P H L E T M C P 706-123

ENGINEERING DESIGN HANDBOOK

Mt* ******

HYDRAULIC FLUIDS REDSTONE SCIENTIFIC INFORMATION CENTER

5 0510 00036039 3

H E A D Q U A R T E R S , U . S . A R M Y AT E R I E L O M M A N D PRIL 971

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AMCP 706-123

TABLE OF CONTENTS (cont'd)

Paragraph a ge

2-7.1.3

neumatic-loaded Accumulators

2 2 2-7.2

ccumulator Selection Considerations 23 2-8

ALVES

2 4

2-8.1

alve Configurations

2 4 2-8.1.1

liding-spool Valves

24

2-8.1.2 eating Valves

-24

2-8.1.3 low-dividing Valves

24

2-8.2 alve Types

24

2-8.2.1 ressure-control Valves 26 2-8.2.2 irectional-control Valves

28

2-8.2.3

olume-control Valves -30 2-8.3

alve Actuation

31

2-8.3.1

anual Actuation 31 2-8.3.2

pring Actuation

31

2-8.3.3

am Actuation 31 2-8.3.4

olenoid Actuation

2-31

2-8.3.5

ilot Fluid Actuation

32

2-8.3.6

ervomechanism Actuation

32

2-8.4 rinciples of Valve Analysis

32

2-8.5 alve Design Considerations 33 2-9 EAT EXCHANGERS 35 2-9.1 odes of Heat Transfer

35

2-9.1.1 onduction

35

2-9.1.2

onvection 35 2-9.1.3

adiation

36

2-9.1.4

verall Heat Transfer Coefficient

36

2-9.2

ypes of Cooling Systems

36

2-9.2.1

ir-cooled Heat Exchangers

37

2-9.2.2

ater-cooled Heat Exchangers

37

2-10

YDRAULI C PIPING

38

2-10.1

ydraulic Line Size

38

2-10.1.1 ressure Drop 38 2-10.1.2 ressure Surges 39 2-10.1.3 ipe an d Tubing Sizes 39 2-10.2 ose, Tubing, an d Pipe Fittings

39

2-11 HOCK ABSORBERS

39

2-11.1

ydraulic Shock Absorbers

40

2-11.2

ydropneumatic Shock Absorbers 41 2-11.3

ydraulic Fluid Properties Pertinent to Shock Absorbers 44 2-12

IQUID SPRINGS

44

REFERENCES - 4 4

CH A PT E R 3 FLUID PRO PE RT I E S , SIGNIFICANCE, A ND T E ST M E T H O D S

3- 0 IS T OF SYMBOLS 1 3-1 ENERAL 1

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AMCP 706-123

TABLE OF CONTENTS (cont'd) Paragraph age

3- 2

HYSICAL PROPERTIES

2

3-2.1

iscosity 2

3-2.1.1

bsolute Viscosity

2

3-2.1.2

inematic Viscosity

3

3-2.1.3

ther Viscosity Scales 3 3-2.1.4

iscosity Unit Conversions

3

3-2.1.5 ewtonian Fluids

4

3-2.1.6 on-Newtonian Materials

4

3-2.1.7 etermination of Viscosity of Non-Newtonian Materials

5

3-2.1.8 urbulent Flow an d Reynolds Number 6 3-2.1.9 easurement of Viscosity 6 3-2.1.10

ignificance of Viscosity 7 3-2.1.11

est Methods for Viscosity

7

3-2.2

iscosity-temperature Properties

8

3-2.2.1

ST M Viscosity-temperature Charts 9 3-2.2.2

ST M Slope

9

3-2.2.3

iscosity-temperature Coefficient 11 3-2.2.4

iscosity Index 11 3-2.2.5

est Methods for Viscosity-temperature Properties 1 3

3-2.3 iscosity of Blends of Two Liquids

14

3-2.4 iscosity-pressure Properties 14 3-2.5 iscosity-shear Characteristics

16

3-2.5.1 emporary Viscosity Loss Due to Shear

16

3-2.5.2 ermanent Viscosity Loss Due to Shear

1 8

3-2.5.3

est Methods for Viscosity-shear Characteristics 1 8 3-2.6

ow-temperature Properties

1 8

3-2.6.1

loud Point -20 3-2.6.2

ou r Point -20 3-2.6.3

reezing Point -20 3-2.6.4

est Methods for Low Temperature Properties -20 3-2.6.5

ignificance of Cloud an d Pour Points

22

3-2.7

lammability Characteristics 2 2

3-2.7.1 lash an d Fire Points

2 2

3-2.7.1.1 es t Methods for Flash an d Fire Points 22 3-2.7.1.2 ignificance of Flash an d Fire Points

24

3-2.7.2 lammability Tests Under Simulated Service Conditions

-24

3-2.7.3 ffects of Evaporation on Flammability (Pipe Cleaner Test)

27

3-2.7.4 utoignition Temperature

27

3-2.7.5

ire-resistant Liquids

2 8

3-2.8

olatility

-28

3-2.8.1

apor Pressure

32

3-2.8.2

oiling Point 32 3-2.8.3

vaporation

33

3-2.9

ensity, Specific Gravity, and Thermal Expansion

35

3-2.9.1

ensity

35 3-2.9.2

pecific Gravity

38

3-2.9.3 PI Gravity -40 3-2.9.4 oefficient of Cubical Expansion

-40

3-2.9.5 est Methods fo r Density an d Specific Gravity -40 3-2.10 eat Transfer Characteristics

42

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Paragraph a 8e

3-2.10.1

pecific Heat 42 3-2.10.2

hermal Conductivity 42 3-2.11

ompressibility and Bulk Modulus

-44

3-2.11.1

ompressibility -44 3-2.11.2

ulk Modulus

45

3-2.11.2.1 ecant Bulk Modulus

45

3-2.11.2.2 angent Bulk Modulus

46

3-2.11.3 onic BulkModulus

46

3-2.11.4 easurement of Bulk Modulus

47

3-2.11.4.1

ecant and Tangent BulkModuli

47

3-2.11.4.2

onic Bulk Modulus

48

3-2.11.4.3

stimation of Bulk Modulus (Penn State Method)

49

3-2.11.4.4

stimation of Bulk Modulus (Other Methods)

51

3-2.12

mulsions an d Foaming in Hydraulic Fluids 51 3-2.12.1

mulsion Characteristics 51 3-2.12.2

oaming Characteristics

52

3-2.12.3

ests for Emulsion an d Foaming Characteristics 52 3-2.13

as Solubility

54

3-2.14 ow-temperature Stability

55

3-2.14.1 eneral

55

3-2.14.2 est Methods fo r Low-temperature Stability

56

3-2.15 edimentation 56 3-3 UBRICATIONPROPERTIES 57 3-3.1 eneral

57

3-3.2

ydrodynamic Lubrication 57 3-3.3

ransition from Hydrodynamic to Boundary Lubrication

57

3-3.4

oundary Lubrication 58 3-3.5

xtreme Pressure Lubrication 59 3-3.6

efinition of Terms Used in Describing Lubricating Characteristics

59

3-3.6.1

ilm Strength

3-59

3-3.6.2

iliness

59

3-3.6.3 ubricity 59 3-3.7 revention of Wear

-60

3-3.7.1 echanical Factors

-60

3-3.7.2 ubrication Factors

-60

3-3.8 es t Methods fo r Lubricating Properties -60 3-3.8.1

ench-type Friction an d Wear Testers

61

3-3.8.1.1

imken Tester 61 3-3.8.1.2

lmen Tester

61

3-3.8.1.3

alex Tester

61

3-3.8.1.4

our-ball Tester

62

3-3.8.1.5

AE Tester

63

3-3.8.2

valuation of Lubricating Properties by Pump Tests 63 3-3.8.2.1

imulative Recirculating Pump Test

63

3-3.8.2.2 um p Loop Wear Test 64 3-3.8.3 ther Lubricating Characteristics Tests 64 3-3.8.3.1 oad-carrying Ability of Lubricating Oils at 400° F .

64

3-3.8.3.2 oad-carrying Capacity of Steam Turbine Oils

3-64

v

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Paragraph age

3-3.8.3.3

ear Fatigue Characteristics of Aircraft Gas Turbine Lubricants at 400° F

64

3-3.8.3.4

oad-carrying Ability of Lubricating Oils (Ryder Gear Machine)

-64

3-4

HEMICAL PROPERTIES 65

3-4.1

hemical Stability 65 3-4.2

xidation Stability

65

3-4.3 hermal Stability

66

3-4.4. ydrolytic Stability

67

3-4.5 adiation Resistance 68 3-4.6 hemical Stability Tests

69

3-4.6.1 ndicators of Liquid Stability

-70

3-4.6.1.1

olor -70 3-4.6.1.2

eutralization Number

70

3-4.6.1.3

arbon Residue 71 3-4.6.2

xidation Stability Tests

72

3-4.6.2.1

xidation-corrosion Test

72

3-4.6.2.2

team Turbine Oxidation Test

72

3-4.6.2.3

vaporation Tests

73

3-4.6.2.4

hin Film Oxidation Tests

73

3-4.6.2.5 ornte Oxidation Test

73

3-4.6.3 hermal Stability Tests 73 3-4.6.3.1 en n State Bomb Test 73 3-4.6.3.2 igh-temperature Test

73

3-4.6.3.3 ustained High-temperature Stability Tests 73 3-4.6.3.4

ow-temperature Stability Test

74

3-4.6.4

ydrolytic Stability Tests 74 3-4.6.4.1

everage Bottle Test

74

3-4.6.4.2

ther Hydrolytic Stability Tests

-74

3-4.6.5

adiation Resistance Tests

-74

3- 5

ORROSIVENESS 75

3-5.1

hemical Corrosion 75

3-5.2

lectrochemical Corrosion

75

3-5.3

orrosiveness Tests

76

3-5.3.1 etal-liquid Corrosiveness Tests

76

3-5.3.2 umidity-type Corrosiveness Tests

76

3-5.3.3 ear-box an d Engine Corrosiveness Tests

79

3-6 OMPATIBILITY

79

3-6.1 ydraulic Fluid Compatibility With Metals -80 3-6.1.1

etal Fatigue

81

3-6.1.2

avitation

81

3-6.2

lastomers

83

3-6.2.1

asic Elastomer Materials

85

3-6.2.2

ffect of Radiation on Elastomers, Plastics, an d Resins

87

3-6.2.3

est Methods for Elastomer-liquid Compatibility

92

3-6.3

ompatibility With Coatings

93 3-6.3.1

ompatibility With Paints

93

3-6.3.2 ompatibility With Other Coatings

93

3-6.4 ompatibility With Other Lubricants

93

3-6.5 ompatibility With Additives

96

REFERENCES

96

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AMCP 706-123


Paragraph aje

CH A PT E R 4 T Y PE S O F H Y D RA U L I C FLUIDS

4-1

ENERAL

1 4- 2

LASSIFICATION OF HYDRAULI C FLUIDS

1

4-2.1 lassification by Physical Properties

1

4-2.2 lassification by Chemical Properties

1

4-2.3 lassification by Operating Characteristics

2

4-2.4 lassification by Fire Resistance 2 4-2.5 lassification into Petroleum or Nonpetroleum Hydraulic Fluids

2

4-2.6 lassification Used in This Handbook 3 4- 3 ETROLEUM BASE HYDRAULI C FLUIDS

3

4-4

ONPETROLEUM BASE HYDRAULI C FLUIDS

3

4-4.1

hosphate Esters 3

4-4.2

ilicate Esters

5

4-4.3

rganic Acid Esters 5

4-4.4

olysiloxanes

5

4-4.5

lycols

5

4-4.6 astor Oils

6

4-4.7 olyoxyalkylene Glycols 6 4-4.8 ater Glycols

6

4-4.9 mulsions

7

4- 5 ONSPECIFICATION AND POTENTIAL HYDRAULI C FLUIDS

7

4-5.1 etroleum Base Fluids 7 4-5.2

onpetroleum Base Hydraulic Fluids

7

4-5.2.1

hosphate Esters 7 4-5.2.2

alogenated Compounds

8

4-5.2.2.1

olysiloxanes (Silanes)

8

4-5.2.2.2

ydrocarbons

8

4-5.2.2.3

erfluorinated Polymers

9

4-5.2.3

olyphenyl Ethers 9

4-5.2.4 eterocyclic Compounds

9

4-5.2.5 hosphonitrilates

9

4-5.2.6 iquid Metals

9

4- 6 YDRAULI C FLUID A ND LUBRI CANT SPECIFICATIONS 10 4-7 ISCOSITY-TEMPERATURE GRAPHS

55

C H A P T E R 5 ADDITIVES

5-1

ENERAL

1

5- 2

XIDATION INHIBITORS

1

5-2.1

ode of Action of Antioxidants 1

5-2.2

lasses of Antioxidants an d Synergism

2

5-2.2.1

etal Deactivators

2

5-2.2.2 ree Radical Acceptors 2 5-2.2.3 ydroperoxide Destroyers

2

5-2.2.4 ynergism

-2

5-2.3 xamples of th e Use of Inhibitors in Various Fluid Lubricants 2

vii

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A MCP 706-123


Paragraph a 8e

5-2.3.1

sters

2

5-2.3.2

ighly Refined Mineral Oils

3

5-2.3.3

ilicon-containing Fluids 3

5-2.3.4

thers

3 5-3

ORROSION INHIBITORS

4

5-3.1 efinitions

4

5-3.2 od e of Action of Rust Inhibitors

4

5-3.3 imitations in the U se of Rust Inhibitors

-4

5-3.4 xamples of Rust an d Corrosion Inhibitors

5

5-3.5 olatile Corrosion Inhibitors

5

5- 4 ISCOSITY INDEX IMPROVERS 6 5-4.1

ode of Action 6 5-4.2

imitations

6

5-4.3

xamples of Effective Polymers

6

5-5

O A M INHIBITORS, EMULSIFIERS, A N D DEMULSIFIERS

7

5-5.1

haracteristics of Foams an d the Mode of Foam Inhibition

7

5-5.2

xamples of Foam Inhibitors

7

5-5.3

mulsifiers an d Demulsifiers 8

5-6.

UBRICITY

8

5-6.1 ydrodynamic vs Boundary Lubrication

8

5-6.2 iliness, Antiwear, an d Extreme-pressure Additives

8

5-6.2.1 iliness Additives

8

5-6.2.2 ntiwear Additives

9

5-6.2.3

xtreme-pressure Additives 9 5-6.3

lasses of Lubricity Additives 9 5-6.3.1

dditives fo r Mineral Oils an d Esters

9

5-6.3.2

dditives fo r Silicon-containing Fluids

9

5-6.3.3

dditives fo r Aryl Ether Fluids -10 5-7

OURPOINTDEPRESSANTS -10

5- 8

EAL DEGRADATI ON RETARDANTS

-10

5- 9

YDROLYTIC INHIBITORS -10

5-10

AVITATION INHIBITORS

11

5-11 IOCIDES

11

REFERENCES

- 1 1

C H A P T E R 6 STO RA G E A N D H A N D L I N G

6-1 ONTAINERS

1

6-1.1

eneral

1

6-1.2

ontainer Materials 1

6-1.3

ontainer Sizes, Storage, an d Marking

1

6- 2

ONTAMINANTS

3

6-2.1

ources of Contamination 3

6-2.1.1

ontamination from Lint an d Dust 3

6-2.1.2 oisture Contamination During Storage 3 6-2.1.3 ontamination Accompanying Additives

3

6i2.2 ypes of Contaminants 5 6-2.2.1 ater As a Contaminant

5

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AMCP 706-123

TABLE OF CONTENTS (concluded)

Paragraph age

6-2.2.2

olid Contaminant Particles

6

6-2.2.3

iquid Contaminants Other Than Water

6

6-2.2.4

icrobiological Contaminants 7 6-2.3

ffects of Contamination

8

6-2.3.1

ffects of Contamination on the Hydraulic Fluid 8

6-2.3.2 ffects of Contamination on the Hydraulic System

8

6-2.4 ethods of Determining Contamination 9 6-2.4.1 olidParticle Contamination Measurement by Counting

9

6-2.4.2 olidParticle Contamination Measurement by Weighing

10

6-2.4.3 olidParticle Contamination Measurement by Combined Counting an d Weighing Methods

10

6-2.4.4

iquid Contaminant Measurement

10

6-3

RECAUTIONS

11

6-3.1

ealth Hazard 11

6-3.1.1

recautions Against Poisoning 11 6-3.1.2

recautions Against Dangerous Vapors an d Sprays

1 2

6-3.2

anger of Explosion an d Fire

12

6-3.3

ther Precautions

12

REFERENCES

- 1 2

GLOSSARY

- l

INDEX

- 1

8/11/2019 884519


AMCP 706-123

UST OF ILLUSTRATIONS

Fig. No.

itle

age

1 -1

raphic Symbol fo r a Three-position, Four-port Hydraulic Valve

3

1-2

raphic Symbols for (A ) a Hydraulic Pump With Variable Displacement an d Pressure

Compensation; an d (B ) a Hydraulic'Motor WithVariable Displacement

-3

1-3 raphic Symbol for a Hydraulic Oscillatory Device

-3

1-4 raphic Symbol fo r a Variable-flow Hydraulic Volume Control, Such as a Needle Valve

-3

1- 5 raphic Symbol fo r a Pressure Relief Valve

-3

2-1

otary Motor Circuit Which Produces Constant Torque 2

2-2

pu r Gear Rotary Hydraulic Pump

3

2-3

ypical Operating Characteristic Curves fo r a Spur Gear Rotary Hydraulic Pump

4

2-4 rescent Seal Internal Gear Hydraulic Pump 4

2-5 erotor Internal Gear Hydraulic Pump 4

2-6 ypical Operating Characteristic Curves fo r a Vane Hydraulic Pump -5

2-7

nbalanced Vane Hydraulic Pump

5

2-8

ane-type Hydraulic Pumps an d Motors 5

2-9

alanced Vane Hydraulic Pump

6

2-10

xial-piston Hydraulic Pump

6

2-11 edial-piston Hydraulic Pump With Rotating Piston Housing

7

2-12 adial-piston Hydraulic Pump With Spherical Pistons 7

2-13 otating Piston Hydraulic Pump 7

2-14

wo-rotor Screw Hydraulic Pump With Helical Gears 8

2-15

ypical Bellows Pump 8

2-16

ypical Diaphragm Pump

9

2-17

otating Linear Actuator

9

2-18 lunger-type Linear Actuator

1 0

2-19 elescoping Linear Actuator 10

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AMCP 706-123

LIST OF ILLUSTRATIONS (cont'd)

Fig. No.

itle

age

2-20

ouble-acting Linear Actuator

1 0

2-21

tepped-tandem Linear Actuator

11

2-22 ual Linear Actuator

11

2-23 ushioned Double-acting Linear Actuator

11

2-24

ounting Arrangements fo r Linear Actuators 12

2-25

pplications of Linear Actuators

13

2-26

ypical Operating Characteristic Curves for a pur Gear Hydraulic Motor

1 4

2-27

ypical Operating Characteristic Curves fo r a Crescent Seal Hydraulic Motor

-14

2-28 ypical Operating Characteristic Curves fo r a Gerotor Hydraulic Motor

-15

2-29 ypical Operating Characteristic Curves fo r a Vane Hydraulic Motor

-1 5

2-30 ypical Single-vane Actuator

16

2-31

ypical Double-vane Actuator

16

2-32

elix-spline Rotary Actuator

16

2-33

iston-rack Rotary Actuator 16

2-34 iagram of a Hydraulic Intensifier Circuit

18

2-35 asic Configurations of Filter Assemblies

2 0

2-36 ydraulic Fluid Filter With Disk-type Filter Elements 20

2-37

eight-loaded Hydraulic Accumulator

22

2-38

pring-loaded Hydraulic Accumulator

22

2-39

onseparated Pneumatic-loaded Hydraulic Accumulator

22

2-40 iaphragm-type Pneumatic-loaded Hydraulic Accumulator

23

2-41 ladder-type Pneumatic-loaded Hydraulic Accumulator 23

xi

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AMCP 706-123


Fig. No.

id e

age

2-42

ree-floating Piston, Pneumatic-loaded Hydraulic Accumulator 23

2-43

ajor Types of Sliding-spool Hydraulic Valve Configurations

25

2-44

ketch of a Flapper Seating Valve 25

2-45 irect Spring-loadedPoppet-type Pressure Relief Valve

25

2-46 et-pipe Flow-dividingValve 26

2-47

irect-acting Pressure-relief Valve 26

2-48

ifferential Pressure-relief Valve 26

2-49

ilot-operated Pressure-relief Valve 27

2-50 ilot-operated Unloading Valve 27

2-51 oad-dividing Valve

27

2-52

equence Valve 27

2-53

ounterbalance Back-pressure Valve 27

2-54

ressure Reducing Valve (Constant Downstream Pressure)

28

2-55 ressure RegulatingValve (Constant Pressure Differential) 28

2-56 ressure Switch 28

2-57 oppet-type Check Valve

29

2-58

ilot-operated Check Valve 29

2-59

echanically Operated, Nonadjustable Deceleration Valve 29

2-60

hree-port Shuttle Valve

- 30

2-61 ime-delay Valve

30

2-62 isk-type Globe Valve

30

xii

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A M C P 706-123


Fig. No.

itle

age

2-63

eedle Valve 30

2-64

ressure-compensated Flow-control Valve

30

2-65

ositive-displacement Metering Valve

31

2-66 ressure-compensated Flow-divider 31

2-67 wo-stage Spool-type Servovalve

32

2-68 ervovalve Transducers

32

2-69

ervovalve Internal Feedback Systems

33

2-70

low Gain of a Spool Valve

34

2-71

ounterflow Plane Wall Heat Exchanger 37

2-72 ydraulic Circuit With Air-cooled Heat Exchangers

37

2-73 hell an d Tube Single-pass Heat Exchanger 38

2-74 ypical Flare Fittings for Hydraulic Tubing

41

2-75 ypical Flareless Fittings fo r Hydraulic Tubing

41

2-76

ypical Self-sealing Couplings fo r Hydraulic Hose

42

2-77

ross-sectional Sketch of a Typical Shock Absorber 43

2-78

ketch of a Hydropneumatic Shock Mechanism

43

2-79 ketch of a Hydropneumatic Recoil Mechanism 43

3-1 elocity Distribution in a Liquid Between Tw o Parallel Plates With the Top Plate Moving With Respect to the Stationary Bottom Plate - 2

3-2 iscosity and Shear Stress Curves for a Newtonian Fluid

4

3- 3

iscosity an d Shear Stress Curves for a Plastic Material

4

3-4

iscosity an d Shear Stress Curves for a Pseudoplastic Material 5

3- 5

iscosity an d Shear Stress Curves fo r a Dilatant Material

5

3- 6 iscosity an d Shear Stress Curves for a Thixotropic Material

5

8/11/2019 884519


AMCP 706-123


Fig. No.

itle

age

3.7

iscosity and Shear Stress Curves for a Rheopectic Material

-5

3- 8

iscosity Curves fo r a Newtonian Fluid and a Non-Newtonian Fluid

6

3- 9

treamline Flow an d Turbulent Flow in a Pipe 6

3-10 annon-Fenske Capillary Tube Viscometer 7

3-11 ross-sectional View of a Saybolt Viscometer 7

3-12

annon-Master Viscometer

8

3-13

iscosity-temperature Graphs of Four Military pecification Hydraulic Fluids

-10

3-14

ethod of Calculating the ASTM Slope of a Hydraulic Fluid 12

3-15 chematic Representation of Viscosity Index (V.l.)

13

3-16 iscosity Blending Chart 15

3-17 iscosity vs Pressure at Several Temperatures fo r a Typical Petroleum Fluid -16

3-18

iscosity vs Temperature at Various Pressures for MLO-60-50 Fluid

-17

3-19

chematic Diagram of Pump Test Apparatus fo r Determining Shear Stability of Hydraulic

Fluids 1 9

3-20 ffect of Shear Upon Viscosity of a MIL-H-5606B Hydraulic Fluid in a Pump Test 20

3-21 ffect of Sonic Irradiation on the Viscosity of a MIL-H-5606B Hydraulic Fluid -20

3-22

leveland Open Cup Flash an d Fire Point Test Apparatus

23

3-23

igh-pressure Spray Ignition Test Apparatus

25

3-24

ow-pressure Spray Ignition Test Apparatus 25

3-25 ot Manifold Ignition Test Apparatus

2 6

3-26 est Apparatus for the Pipe Cleaner Evaporation Test

2 7

x iv

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LIST OF LLUSTRATIONS cont'd)

Fig. N o. Title

age

3-27

utoignition Temperature Test Apparatus

28

3_28

pontaneous Ignition Temperature of a MIL-O-5606 luid in A ir in Contact With Various

Surfaces As a Function of Test Chamber Pressure

29

3-29 pontaneous Ignition Temperature of a Chlorinated Phenyl Methyl Silicone in A ir in Contact With Various Surfaces As a Function of Test Chamber Pressure 30

3-30 pontaneous Ignition Temperature of Seven Hydraulic Fluids at Atmospheric Pressure in Contact With a Pyrex Glass Surface As a Function of Oxygen Concentrations 31

3-31

apor Pressure vs Temperature of Typical Fluids (Approximate)

33

3-32

apor Pressure vs Temperature of Several Types of Hydraulic Fluids

34

3-33 ut-away Sketch of the Evaporation Loss Apparatus Used n ASTM D-972 Test Method 35

3-34 ensity vs Temperature of Typical Fluids Approximate)

36

3-35

ensityvs Temperature of Several Types of Hydraulic Fluids at Atmospheric Pressure 37

3-36

elative Density vs Pressure at Several Temperatures of a Typical Fluid Conforming to

MIL-H-5606B

-38

3-37 ensity vs Pressure at Several Temperatures for MLO-60-50 Fluid (an ester of trimethylolpropane) 39

3-38 oefficient of Cubical Expansion vs Temperature of Several Types of Hydraulic Fluids

40

3-39

ipkin Bicapillary Pycnometer fo r Determining Density an d Specific Gravity of Liquids

41

3-40

ingham Pycnometer fo r Determining Density and Specific Gravity of Liquids

41

3-41

pecific Heat vs Temperature of Several Types of Hydraulic Fluids 43

3-42 hermal Conductivity vs Temperature of Several Types of Hydraulic Fluids 44

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LIST OF I LLUS TRATI ONS (cont'd)

Fig. N o.

itle Page

3-43

luid Percent Volume Compression vs Pressure of Typical Fluids 45

3-44

ulk Modulus vs Pressure-A Generalized jlelationship for a Variety of Fluids Over

the Range of 32° o 425°F

47

3-45

xample Representation of Secant an d Tangent Bulk Moduli 48

3-46 pparatus for Measurement of Adiabatic Bulk Modulus by Sonic Speed 49

3-47 raph of Constant Used in Eq. 3-27

-50

3-48

mulsion Test Apparatus

53

3-49

oaming Test Apparatus 53

3-50

itrogen Solubility vs Pressure of Two Petroleum Products

55

3-51 ir Solubility vs Pressure of Typical Fluids

55

3-52 race Sediment Test Tube

57

3-53

oefficient of Friction in the Transition from Hydrodynamic to Boundary Lubrication

58

3-54

ive Bench-type Friction an d Wear Testers 62

3-55

avity Formation and Collapse Between Rollers or

Gear Teeth

83

3-56 avity Formation an d Collapse in an Orifice 84

3-57 elative Radiation Resistance of Elastomers 89

3-58 elative Radiation Resistance of Thermosetting Resins

-90

3-59

elative Radiation Resistance of Thermoplastic Resins

91

4-1

iscosity-temperature Graphs of Specification Liquids MIL-L- 10295A, M1L-L-21260A,

MIL-H-27601A (USAF), an d MIL-H-46004(ORD)

56

4- 2 iscosity-temperature Graphs of Specification Liquids W-L-800, MIL-L2104B, MIL-F-25598(USAF), an d MIL-L-45199A

57

xvi

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LIST OF ILLUSTRATIONS (concluded)

Fig .No.

ide

age

4-3

iscosity-temperature Graphs of Specification Liquids MIL-H-8446B an d

MIL-H-19457B(SHIPS)

58

4-4

iscosity-temperature Graphs of Specification Liquids MIL-H-5606B, MIL-H-6083C, an d MIL-F-17111(NORD)

59

4-5 iscosity-temperature Graphs of Specification Liquids MIL-L-6085A, MIL-L-7808G, an d MIL-L-23699A

60

4-6 iscosity-temperature Graphs of Commercial Phosphate Ester Liquids

61

4-7

iscosity-temperature Graphs of Commercial Hydrocarbon Liquids

62

4-8

iscosity-temperature Graphs of Commercial Polysiloxane, Halocarbon, an d Fluorolube

Liquids 63

4- 9 iscosity-temperature Graphs of Commercial Phosphate Ester Liquids

64

4-10 iscosity-temperature Graphs of Commercial Halofluorocarbon Liquids 65

4-11 iscosity-temperature Graphs of Specification Requirements for MIL-H-13910B, MIL-H-22072A(WP), an d MII^L-46002(ORD) 66

4-12

iscosity-temperature Graphs of Specification Requirements fo r W-B-680a, MIS-10137,

an d MIL-S-81087A(AGS)

67

4-13 iscosity-temperature Graphs of Specification Requirements for MIL-H-13866B(MR), MIL-L-17672B, an d MIL-H-81019(WEP)

68

4-14 iscosity-temperature Graphs of Specification Requirements fo r MIL-H-13919B, MIL-F-17111(NORD), an d MIS-10150 69

6-1

ne-gal Screw C ap Can, Type V, Class 4 1

6- 2

ne-qt Hermetically Sealed Can, Type I

2

6-3

ne-pt Spout Top Can, Type V, Class 8

2

6- 4 arkings on Top an d Side of 55-gal Drum

4

6-5 arkings on Sides of 5-gal Tight-head Pail

5

xvii

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LIST OF TABLES

Table No.

itle

age

2- 1

oss Coefficients of Hydraulic Systems

39

2-2

imensions an d Characteristics of Pipe fo r Hydraulic Systems 40

2-3

all Thickness Equivalents

40

3-1 iscosity Requirements of Five Specification Hydraulic Fluids

9

3-2 stimated Shear Rates of Lubricants

1 6

3- 3 our Point Requirements of Four Military Specification Fluids 21

3- 4

lash Point Requirement of Five Military Specification Fluids 23

3-5

ulk Modulus

46

3-6

oaming Requirement of Military Specifications

54

3- 7 aximum Operating Temperature of Hydraulic Fluids 67

3-8 xidation an d Varnishing Resistance of Hydraulic Fluids 68

3-9 eterioration Temperature of Hydraulic Fluids 69

3-10

ydrolytic Stability of Hydraulic Fluids

3-69

3-11

adiation Resistance of Hydraulic Fluids

-70

3-12 iquid-metal Corrosiveness Test Methods

77

3-13 xidation-corrosion Limits of Several Military Hydraulic Fluid Specifications 78

3-14 og or Humidity Corrosiveness Test Methods 79

3-15

ear-box Corrosiveness Test Methods -80

3-16

ffect of Mechanical an d Liquid Variables on Cavitation 82

3-17

roperties of Elastomers

84

3-18 ommon Trade Names an d Recommended Uses of Basic Types of Elastomers 86

xviii

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LIST OF TABLES cont'd)

Table No.

itle

age

3-19

omparative Properties of Commonly Used Elastomers

87

3-20

ompatibility of Commercial Hydraulic Fluids With Elastomers

88

3-21

ubber Swell Requirements of Military Specification Hydraulic Fluids

92

3-22 ffect of Hydraulic Fluids on Standard Paints

93

3-23 esistance of Military Specification Coatings to Hydraulic Fluids

94

3-24 esistance of Paints to Attack by Chemical Media

95

4-1

haracteristics of Hydraulic Fluid Base Stocks

4

6 -1

ydraulic Fluid Container Sizes

2

6-2

ecommended Abbreviations

3

6-3

IAParticle Contamination Limits for Hydraulic Fluids

7

6-4 article Contamination Limits for Hydraulic Systems at Martin Aircraft Company 7

6-5 ffects of Various Contaminants on Hydraulic ystem Components

9

6-6 olid Particle Contamination Limits in Hydraulic Fluid Corresponding to MIL-H-5606B ... 6-11

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PREFACE

The Engineering Design Handbook eries of the Army Materiel Command s coordinated series of handbooks containing basic nformation and fundamental data. The handbooks are authoritative reference books of practical information and quantita- tive facts helpful in the design and development of materiel that will meet the tactical and echnical needs of the Armed orces.

The use of hydraulics fo r power transmission and control ha s increased spectacularly in the past few decades. There are numerous reasons fo r this trend. The forces available in electrical systems are limited. Mechanical systems frequently require complex, and sometimes mpractical, inkages or emote se of power. n pplications equiring transmission of large amounts of power r arge forces, he power-to-weight atio of electrical or mechanical systems is enerally much ower than hat of hydraulic ystems. The general field of hydraulic ower transmission as been developing in both the quipment nd luid reas. Virtually very major iece of stationary nd mobile equipment se d y ndustry nd he Armed orces ow ncorporates t east ne hydraulic system.

The objectives of this Handbook are: (1 ) o collect diverse sources of information to conserve time, materials, and money in the successful design of new equipment, (2 ) to provide guidance n apsule orm or ew ersonnel, Armed Forces contractors, or experienced design engineers in other fields who require information about hydraulic fluids, 3) to supply current fundamental nformation, and (4 ) to place the reader in a position o se ew nformation generated ubsequent o he publication of this handbook. To meet hese bjectives, he handbook has een written o provide he necessary background regarding hydraulic equipment and fluids so that more complete information nd data available in he eferences an e utilized.

This handbook is organized into six chapters. Chapter presents the inherent advantages, disadvantages, an d areas of application of electrical, mechanical, and hydraulic systems along with a brief review of the principles of hydraulics. Chapter 2 includes descriptions of the major ypes of hydraulic ircuit omponents nd xplanations, where pplicable, f the methods of operation. hapter iscusses he mportant properties of hydraulic fluids. These discussions re directed oward he significance of each property and the method(s) and accuracy of determination. Chapter 4 presents fluids currently conforming to Federal Specifications along with pertinent information from each specification. This chapter also includes eview of new nonspecification fluids which may find applications under extreme environmental conditions. Chapter 5 iscusses dditives requently equired o modify properties of base tock luids. Chapter 6 presents the methods f handling nd toring hydraulic fluids.

The text of this handbook was prepared by D. R. Wilson, M . E. Campbell, . W . Breed, H. . Hass, and J. Galate of Midwest Research nstitute under subcontract to the Engineering Handbook Office of Duke University, prime contractor o he U.S. Army Materiel Command for the Engineering Design Handbook Series. Many helpful

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comments were supplied by J. Messina of Frankford Arsenal and other members of the Ad Hoc Working Group of which Mr. Messina was chairman.

The Handbooks are readily available to all elements of AMC including personnel and contractors having a need and/or requirement. The Army Materiel Command policy is to release these Engineering Design Handbooks to other DOD activities and their contractors and other Government agencies in accordance with current Army Regula- tion 70-31, dated 9 September 1966. Procedures for acquiring these Handbooks follow:

a. ctivities within AMC and other DOD gencies hould irect heir equest on an official form to :

Commanding Officer Letterkenny Army Depot ATTN: AMXLE-ATD Chambersburg, Pennsylvania 7201

b. ontractors who have Department of Defense ontracts hould ubmit heir requests, hrough heir ontracting officer with proper justification, o he ddress indicated n ar . .

c. overnment agencies other than DOD having eed for the andbooks may

submit

heir request

directly to

the Letterkenny

Army

Depot,

as indicated

in

ar. above, or to : Commanding General U.S. Army Materiel Command ATTN: AMCAM-ABS Washington, D. C. 0315

d. ndustries not having Government ontract (this includes universities) must forward their requests o:

Commanding General U.S. Army Materiel Command ATTN: AMCRD-TV

Washington, D. C. 0315

e. ll oreign equests ust e ubmitted hrough he Washington, . C, Embassy o:

Office of the Assistant Chief of Staff for ntelligence ATTN: Foreign Liaison Office Department of the Army Washington, D. C. 0310

All requests-other than those originating within the DOD-must be accompanied by a alid justification.

Comments and suggestions on this handbook are welcome and should be addressed to:

U.S. Army Research Office-Durham Box C M , Duke Station Durham, North Carolina 27706

XXI

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CHAPTER

INTRODUCTION

1-1 GENERAL

The development of our present level of technology has depended on the evolution of methods for the generation, distribution, and utilization of power. The en - ergy requirements of the domestic population and the national defense effort increase at a rate of 2 to 3 ercent per year. Various estimates place the rate of energy consumption n he nited tates t .0 o .5 X

1017 B tu per year by he year 000 Ref. ). This n- creasing emand or ower equires he ontinued development of methods fo r power transmission, control, nd utilization. Fluid power technology plays an important ole n his ask nd promises o e ven more mportant n he future.

speed with which lectrical ervomechanisms an e- spond. Heat dissipation is a problem of frequent importance in lectrical ower transmission.

1-2.2 MECHANICAL POWER TRANSMISSION

Mechanical power ransmission ystems mploy variety of kinematic mechanisms such as belts, chains,

pulleys, sprockets, gear trains, bar linkages, and cams. They re suitable or the ransmission of motion nd force over relatively short distances. The disadvantages of echanical ystems nclude ubrication roblems, imited peed nd orque ontrol apabilities, uneven orce distribution, nd elatively arge pace requirements.

1 -2

ETHODS OF TRANSMITTING POWER

The majority of contemporary power ransmission systems an e lassified s electrical, mechanical, or fluid. Fluid power systems can be further divided into pneumatic nd hydraulic ystems, depending n he fluid medium se d o ransmit orce. The luids m- ployed n pneumatic ower nd ontrol ystems re gases which are characterized by high compressibility. In contrast, hydraulic fluids are relatively incompressible iquids.

1-2.3 PNEUMATIC POWER TRANSMISSION

Pneumatic power is transmitted by the pressure and flow of compressed gases. The most common gas used

is air. Pneumatic

systems use simple equipment, have

small transmission lines, and do not present a fire hazard. Disadvantages include a high fluid compressibility and a small power-to-size ratio of components. Pneu- matic power systems are more elastic than mechanical systems and are very sensitive to small changes in pressure or flow. For this reason they are especially suited for pilot or control ystems.

1-2.1 ELECTRICAL POWER TRANSMISSION

Power s ransmitted lectrically y mposing n electromagnetic field on a conductor. Electric systems are especially suitable for power transmission over long distances and are best applicable to low-power operations.

Magnetic aturation, undamental imitation f electrical machines, imits the torque developed by an electric otor. Material imitations lso ffect he

1-2.4 HYDRAULIC OWER TRANSMISSION

Hydraulic power is transmitted by the pressure and flow of liquids. For many years petroleum oils were the most ommon iquids, but other ypes of liquids re no w inding idespread se . ydraulic ystems re mechanically tiff, nd an e esigned o ive as t operation and move very large loads. They can be employed ver greater distances han mechanical ypes but ot s far as electrical systems.

1-1

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Fitch Ref. ) ists he following dvantages of hy - draulic ower systems:

(1 ) arge orques nd orces ransmitted o ny part of a machine

(2 ) ushioning fo r shock oads (3 ) eversible, nfinitely ariable peed nd oad

control

(4 )

ompletely utomatic operations (5 ) ccurate position control for linear and rotary elements

(6) ower inkage where kinematic inkage s m- practical

(7) eduction of wear by the self-lubrication action of the transmission medium

(8) afe power system operation for both operator and machine.

Some of the major disadvantages of hydraulic ystems re :

(1 ) mpairment of system operation by contamination

(2 ) ydraulic fluid leakage (3 ) ire hazards with lammable hydraulic fluids. The unctions of a hydraulic luid re o ransmit

force applied at on e point in the system to some other location and to produce an y desired change in direction or magnitude of this force. To carry out this function in the most efficient manner, the hydraulic fluid must be relatively incompressible and must flow readily. n addition, he ydraulic luid ust erform ertain other functions-such as lubrication and cooling-which are secondary in nature, but are important to the overall operation of the hydraulic system.

1 -3 RINCIPLES OF HYDRAULICS

1-3.1 GENERATION A N D USE OF FLUID POWER

The use of hydraulic fluids to generate and transmit power s ased upon physical aws which overn he mechanics of liquids. The principles of fluid mechanics, including both hydrostatics and fluid dynamics, have been developed over a period of several centuries and now onstitute undamental branch of science nd engineering. A nowledge of the pplication of these principles to the design and use of fluid power systems can be obtained by a study of an y of several references drawn from the vast literature of fluid mechanics (Refs. 2, , , ).

1 -2

1-3.1.1 Fluid ower Circuits

The application of fluid power requires some type of fluid circuit. Many different circuit designs are possible for a given pplication. However, most hydraulic circuits epresent om e variation of a ew asic ircuit designs uc h s pump ircuits, luid otor ircuits, accumulator or intensifier circuits, and control circuits.

A ll hydraulic circuits consist of some combination of six basic components: 1) a source of pressure, .g., pump; (2 ) a means of converting pressure into mechanical otion, .g., ydraulic motor or ctuator; 3) fluid-transfer piping; (4) pressure, directional, an d flow controls; (5 ) a fluid reservoir; and (6) a hydraulic fluid. The output of the hydraulic circuit is determined by the manner in which the various components are arranged. The individual components are described in Chapter 2.

1-3.1.2 Symbolic Representation of Components

The apid development of fluid-power applications following World War I reated eed or tandard fluid ower ymbols nd pecifications o acilitate communication nd rovide a widely ccepted means of representing fluid-power systems. This need was first met by the Joint Industry Conference (JIC) which published et of graphical ymbols or ystem omponents in September 1948. In 1958, the American Stand- ards Association (ASA) adopted symbols based upon a revision of the JIC symbols. Sincethen, the ASA standards have been periodically revised. The current standard s U SA Standard Y32.10-1967, raphic Symbols for Fluid Power Diagrams (Ref. ).

Graphic luid ower ymbols re ow widely se d both or preparing ircuit diagrams nd s n id n circuit design and analysis. They illustrate flow paths, connections, and component functions but do not indicate perating arameters r onstruction etails. There are nine basic symbol lassifications-fluid conductors, nergy nd luid torage, luid onditioners, linear evices, ontrols, otary evices, nstruments and accessories, valves, and composite symbols. A de - tailed iscussion f the use and meaning of the A SA fluid power symbols can be found in the ASA Standard (Ref. ); owever, brief explanation of a few of the more ommon ymbols will id he eader n urther study.

(1 ) alves: The basic alve symbol consists of on e or more quares alled nvelopes, he number of en- velopes corresponding to the number of valve positions. Inside ach nvelope re ines epresenting he low

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path nd low conditions between ports. The connection ines re drawn o the nvelope epresenting he neutral position. The flow paths of the actuated valve are isualized y mentally hifting he orresponding envelope to he port position. Consider, or xample, the three-position valve illustrated in Fig. -1 . The normal position of the our-port alve is hat of blocked

flow, represented by the center envelope. To obtain the flow ondition epresented y he eft nvelope, hat envelope is mentally shifted to the center position. Con- versely, he crossed-flow path of the right envelope is obtained by mentally shifting the right envelope to the center position. Multiposition, multiport valves of an y complexity can be represented by a suitable combination of such ymbols.

W X Fig. 1-1. Graphic ymbol or Three-position, our-

port Hydraulic Valve

(2 ) otary pumps and motors: The basic symbol for a hydraulic pump is a circle with connecting lines n- dicating ports, nd riangles indicating flow direction (Fig. -2(A)). Variable displacement is indicated by an arrow through the envelope at an angle. Pressure compensation is denoted by a short vertical arrow. Motors are distinguished rom pumps y he ocation of the flow direction triangles. Flow triangles point outwards for pumps and nwards fo r motors Fig. -2(B)). The

envelope fo r an oscillatory device is a closed semicircle (Fig. -3).

Fig. 1-2. raphic Symbols or A ) ydraulic ump With Variable Displacement an d Pressure Com- pensation; nd B) Hydraulic otor With Variable Displacement

Fig. 1-3. raphic ymbol or Hydraulic scillatory Device

(3 ) olume controls: Orifice-type volume flow controls, uc h s lobe nd eedle alves, re ndicated graphically by arcs on both sides of the flow line (Fig. 1-4). f the size of the restriction is variable, an arrow is placed t n ngle hrough he ymbol. ressure compensation is indicated by adding a rectangular envelope and a small vertical arrow across the flow line.

Fig. 1-4. raphic Symbol fo r a Variable-flow Hydraulic Volume Control , Such as a Needle Value

(4 ) ressure controls: Pressure relief valve symbols consist of a square envelope with a closed normal position and an actuated position which relieves to a reservoir. Upstream pilot pressure is shown by a broken line (Fig. -5). Pressure reducing valves have an open neutral osition nd downstream ilot ressure.

A A i- d7

-j

Fig. 1-5. raphic Symbol for a Pressure Relief Valve

1-3.1.3 Uses of Hydraulic Power

The manner in which hydraulic power can be put to use is limited primarily by he imagination of the de - signer. Hydraulic power has found ts most xtensive use n anufacturing nd onstruction achinery. Fluid-power perated resses nd aterial-handling machinery re ommon ixtures n ny roduction plant. In construction an d earth-moving industries, hy - draulic power is used on almost every piece of equipment. Other ndustries making xtensive se of fluid power are aerospace, griculture, petroleum, utomotive, hemical, nd food processing.

1 -3

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1-3.2 REQUIREMENTS FOR HYDRAULIC FLUIDS

The hydraulic luid s n ssential nd mportant component of an y hydraulic power or control system. No other omponent of the ircuit must perform s many unctions or meet s many equirements as the

hydraulic fluid. The hydraulic fluid must not only provide a medium for efficient power transmission, but it must lso ubricate, ool, protect rom corrosion, not leak xcessively, nd erform umerous other unctions depending on the system design. However, ven if a hydraulic fluid can adequately perform these system unctions, t may still be less than atisfactory n terms of usage and compatibility factors. n many hy - draulic systems, it is necessary that the hydraulic fluid be nontoxic nd ire-resistant. t must e ompatible with he tructural materials of the ystem. The y- draulic luid hould xhibit table physical properties during uitable period of use. t hould e asy o

handle when in use and in storage, and it is desirable, of course, that it be readily available and inexpensive.

The election of a hydraulic luid s urther om - plicated by the vast number of liquids currently available. These range from water and mineral oils to special- purpose synthetic iquids. t s thus necessary or the system designer to have at least an elementary under- standing of the terminology prevalent in the specification of hydraulic luids.

1-3.2.1 System Dependency of the Hydraulic Fluid

1-3.2.1.1 Temperature

Temperature s ystem parameter ather han characteristic of the fluid. However, the physical properties of hydraulic fluids are influenced by the operating emperature. igh emperature an ause e- crease in viscosity and lubricity, resulting in increased leakage hrough eals nd etrimental riction nd wear. any ydraulic luids xperience olecular breakdown t elevated emperatures.

Viscosity increases with decreasing temperature, and

thus the lowest operating temperature for a given liquid is that corresponding to the maximum viscosity which can be satisfactorily accommodated by he system.

Hence, an important requisite in the selection of hydraulic luids s thorough knowledge of the torage temperature, he verage operating emperature, he high and low operating temperatures, and the tempera-

1-4

tures of local ystem hot pots. With hese known, t then becomes necessary to know the manner in which the liquid properties vary within the system emperature range.

1-3.2.1.2 Viscosity

Viscosity, ften eferred o s he most mportant single property of a hydraulic luid, s he property which characterizes the flow resistance of liquid. Low- viscosity iquids ransmit ower ore ffectively, whereas high iscosity s equired o ubricate and o reduce leakage. Thus, the allowable viscosity range de - pends n compromise between he power-transmission characteristics on the on e hand and the sealing and lubricating properties on he other.

Viscosity depends pon emperature nd pressure, and generally increases with decreasing temperature or increasing ressure. he iscosity ndex V.l.) s

measure of the temperature dependence. Liquids with a igh iscosity ndex xhibit maller variation of viscosity with temperature than do liquids with a low V.l. Low-viscosity liquids are less affected by pressure than igh-viscosity iquids. iquids hich xhibit large variation of viscosity with emperature sually exhibit large viscosity change with ressure.

Another factor which can nfluence the viscosity is the rate of shear. Liquids with large polymer molecules can xhibit emporary ecrease n iscosity he n subjected to high shear rates. f the liquid is subjected to hear-rate onditions hich end o reak own large molecules, ermanent hanges n iscosity an

result.Viscosity ffects many operational actors n y-

draulic ystem-mechanical riction, luid riction, pump lippage, avitation, eakage, ower onsumption, and system control ability. The use of a hydraulic fluid with a low iscosity can lead to increased pump slippage, excessivewear of moving parts, and hydraulic fluid loss due to leakage. A viscosity which is too high will cause increased pressure loss and power consumption and, as a result of liquid friction, ca n lead to excessive system emperatures.

1-3.2.1.3 Compatibility With System Materials

Chemical compatibility of a hydraulic fluid with the system materials ometimes equires ompromises n the selection of the hydraulic fluid or the materials of construction. The hydraulic fluid should be chemically inert and should not react with materials of the system

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AMCP 706-123

refers to the shear strength of a thin ubricating ilm. A liquid that forms a film of lo w shear strength is said to have good ubricity.

The ability of a liquid to form a film on a surface is important in lubrication. The film should be capable of supporting he oads ncountered uring peration. Breakdown f he ubricating ilm auses ear nd shortens the

life

of the

system components. In general,

higher viscosity liquids are better able to maintain films than those of lower viscosity. However, system considerations other han ubrication imit he alue of viscosity in some applications. Antiwear additives provide a solution o some of these problems.

1-3.2.1.7 Pressure

The reduction of volume of a liquid under pressure is a measure of the compressibility of the liquid. Com- pressibility influences the power required by the pump, the time required to generate pressure, the speed with which the transmission and control systems respond to input, and the manner in which energy is converted by pressure reduction. The bulk modulus is the reciprocal of the compressibility and is always a positive quantity. A igh bulk modulus ndicates ow iquid lasticity and, ence, small spring effect when ubjected o a pressure change. A iquid with igh ulk modulus s desirable in order to obtain good dynamic performance in a hydraulic system. Entrained air in the fluid reduces the bulk modulus. Pressure and temperature also affect the bulk modulus. For most liquids, the bulk modulus decreases with ncreasing emperature nd lso with decreasing ressure.

1-3.2.1.8 Lacquer and Insoluble Material Formation

The ydraulic luid hould emain omogeneous while n se . The ormation nd deposit of insoluble materials on parts of the system ca n cause system malfunction or failure. nsoluble materials can be formed by many different processes. Oxidation, contamination, thermal degradation, hydrolytic degradation, etc., can all produce insoluble materials. Changes in the hydrau-

lic fluid caused by the above processes can also affect the olubility of additives nd esult n he dditives becoming insoluble. Insoluble materials can plug small orifices, educe learances, damage urfaces, or orm deposits on working surfaces. The deposits show up as coatings, varnishes, acquers, tc.

1-3.2.2 Other Considerations

1-3.2.2.1 Availability

It s bviously desirable hat hydraulic luid e readily available. f a hydraulic fluid possesses widely

applicable properties nd s ompetitive n erms of cost, t will sually be eadily available.

1-3.2.2.2 Cost

Several factors must be considered in the evaluation of the cost of a hydraulic fluid. The original cost, he service longevity, storage costs, and rate of system leakage enter into the overall cost evaluation. The purchase of an expensive hydraulic fluid is justified if its properties can result in ower ultimate system costs because of reduced eplacement requency, ncreased ompo-

nent ife, r ther actors. owever, onsideration should be given to the economy afforded by changes in system design to allow use of a less xpensive hydraulic luid.

1-3.2.2.3 Handling

The ease with which a hydraulic fluid can be handled is important to the user and to maintenance personnel. Toxicity is perhaps the first factor to consider in evaluating handling haracteristics. The hydraulic luid, its vapor, and its decomposition products should have very low toxicity, in terms of inhalation, ngestion, or contact with the skin. Toxic liquids can be used only if extreme precautions re aken o nsure o harmful effects to the operating and maintenance personnel.

A hydraulic fluid should not have an unpleasant or nauseating odor. Although odor does not influence performance, t s important o he ser.

1-3.2.2.4 Storage

The storage characteristics of a hydraulic luid re closely related to chemical stability and handling char-

acteristics. The properties of a hydraulic fluid hould not deteriorate f the luid tands n torage for on g periods. recautions hould e aken o nsure hat contaminants cannot enter the stored hydraulic fluid. Oxidation stability is often se d as a criterion n evaluating the storage characteristics.

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1-3.2.2.5 Contamination

A hydraulic luid s subjected o everal ources of contamination, both in use or in storage. Air and moisture can leak into the system. These contaminants promote oxidation nd ydrolysis. ntrained water an also ause mulsions which, n urn, end o ollect

solid impurities. t should be noted that emulsions are formed more eadily n ontaminated iquids han n clean ones. Solid contaminants can result from fabrica- tion, handling, or cleaning procedures, and from wear debris. olid contaminant particles can increase wear, accelerate corrosion, an d contribute to sludge and foam formation. xidation roducts nd he ompounds formed by dditive decomposition are contaminants.

Several ethods re se d o emove various on - taminants. iltration evices, which re discussed n Chapter 2, can be used to remove solid particles. Mag- netic plugs and filters can remove ferrous metal particles. torage n ettling anks llow olid particles o

settle out by gravitational forces. Centrifuges are sometimes used to remove heavy contaminants. If the liquid has good demulsibility properties, water can be

removed after it separates from the liquid in a reservoir or storage vessel.

REFERENCES

1 . .A . Elliott, What's Ahead n Energy", e-

troleum Management, 70 (October 964). 2. .C . Fitch, luid Power and Control Systems,

McGraw-Hill, nc., New York, 966.

3. .J . ippenger nd .G. icks, ndustrial Hydraulics, cGraw-Hill, nc., ew ork, 1962.

4. .E. Merritt, Hydraulic Control Systems, John Wiley and ons, N ew York, 967.

5. .D. eaple, d. , ydraulic and Pneumatic Power and Control, cGraw-Hill, nc., ew York, 966.

6.

SA Standard Y32.10-1967,

raphic Symbols for Fluid Power Diagrams, American Society of Mechanical Engineers, N ew York, 967.

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CHAPTER

POWER TRANSMISSION EQUIPMENT

2-0 LIST OF SYMBOLS

D De -

F-

f=

G = h =

K = k =

Le =

i = N = P =

Pf =

Pg = p k =

Q =

QP =

R =

°R = Rn =

cross-sectional rea or area of a radiating surface, t2

diameter, n. equivalent diameter, n. force, b; or in heat ransfer, dimensionless factor which accounts for the geometric

orientation of surfaces and their emittances coefficient of friction, or friction factor flow rate, pm convective film oefficient, Btu/(hr)(ft 2)(°F)

friction loss coefficient thermal conductivity, Btu/(hr)(ft 2)(°F/ft) damping length or length of a pipeline, t equivalent length of a ipeline, ft

thickness of a material, t number of pound moles pressure, si or mm Hg

liquid pressure, si gas pressure, si final ccumulator pressure after a pressure or volume change, psi

volumetric flow rate, pm ; or rate of heat low, Btu/hr increase in hermal nergy due to pumping, Btu/hr increase in hermal nergy due

to friction in a valve, Btu/hr universal as constant, 0.72 psia-ft3 /°/Mb mole degrees Rankine (°F+460) thermal esistance of system component , hr-°F/Btu

s = pecific gravity of liquid Ta = mbient emperature T' = inal ambient emperature after

a pressure or volume change U = iquid velocity, ps; or overall

heat transfer coefficient, Btu/(hr)(ft 2(°F)

V = olume, t3 in or cm Vg = inal gas valume Z

g = ompressibility factor of gas,

dimensionless Zg = inal compressibility factor of

gas, imensionless A P = hange in pressure, si A T = emperature difference, F

A Ttotal = ota l temperature difference across which heat s being transferred, °F

T J ecimal operating efficiency o- = tefan-Boltzmann constant,

0.1714 x l(f8Btu/(hrXftY/fl

Note: Where more han ne et f nits ave een specified, or no units specified, a consistent se t of units must be used.

2-1 GENERAL

The preceding chapter pointed out that the hydraulic fluid performs a basic function in a hydraulic power or control ystem nd us t atisfy umerous equirements to perform dequately n iven ircuit. Fur- thermore, he hydraulic fluid influences the operation

of the system components and they, in turn, affect the performance of the hydraulic fluid. Hence, the components of a ystem annot e designed or specified n- dependently of the hydraulic fluid, nor can the hydraulic luid e elected ndependently of the omponent design.The hydraulic circuit, involvingbothmechanical

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hard parameter is defined as a physical quantity which can e measured with ood recision nd which e- mains ssentially onstant. A oft parameter, n he other hand, s a quantity which is difficult to measure or compute and, for a given system, can be determined only ithin ange f alues. he os t mportant design features of a system should be based upon hard

parameters, f possible. Merritt points out that n m- portant part of sound engineering design practice is the ability to distinguish between hard and soft parameters.

2-2 P U MP S

A hydraulic pump is a device used to impart motion to liquid and hereby convert mechanical energy o hydraulic nergy. t rovides he orce equired o transmit power. Pumps are rated in terms of flow an d pressure. he low ating volumetric output) s he amount of liquid which can be delivered by the pump

per unit im e t pecified peed. A pump oe s ot produce pressure. The pressure developed at the outlet depends on the resistance to flow n he circuit.

Pumps re lassified ccording o onfiguration or operating characteristics. One obvious classification s that of rotary or reciprocating pumps. Rotary pumps utilize a rotating assembly to transfer the fluid from the inlet to the outlet an d to impart motion. Rotary pumps can be further classified as gear, vane, or rotating piston pumps. Reciprocating pumps employ a plunger or piston to impart motion o he fluid.

Pumps can also e lassified s ositive- or onpositive-displacement evices. ositive-displacement

pumps move efinite mount of fluid during ach stroke or revolution. They are most frequently used in hydraulic ystems. onpositive-displacement, r y- drodynamic, pumps provide continuous flow. They are primarily ow-pressure evices with igh olumetric output.

Positive-displacement pumps an e of either ixed or ariable displacement. he output f ixed-displacement pump s onstant t iven pump peed. The output of a variable-displacement ump an e changed by adjusting the geometry of the displacement chamber.

2-2.1 GEAR UMPS Gear pumps re he most idely se d pumps or

hydraulic systems. They are available in a wide ange of flow nd pressure ratings. The drive nd ears re the only moving parts.

2-2.1.1 External Gear Pumps

In external gear pumps, two or more gears mesh with minimum clearance. The gear motion generates a suction at the inlet, which causes fluid to bedrawn into the pump housing. The liquid is drawn through the pump an d s displaced as the teeth mesh on he outlet ide.

(1 ) pur gear pumps: A spur gear rotary hydraulic pump is illustrated in Fig. 2-2. The tw o gears rotate in opposite directions and transfer liquid from the inlet to the outlet hrough he olume between he teeth nd the ousing. The output depends on ooth width nd depth, and is largest fo r a minimum number of teeth. Involute teeth with pressure angle of 20-30 de g are common n pur gear umps. owever, rogressive- contact an d edge-contact gears are sometimes se d o avoid the severe loads generated by liquid trapped between he contact points of the meshed involute teeth.

Fig. -2 . Spur Gear Rotary Hydraulic Pu m p

4* [From: H . E. Merrit, Hydraulic ontrol Systems. Used y permission of John Wiley and ons]

The spur gear pump is a fixed-displacement pump. Output t iven peed decreases lightly with ressure. ypical operating haracteristics re hown n

Fig. 2-3. These curves are for a spur gear pump operating with iquid of constant iscosity. This iscosity effect llustrates ne of the ways n which he iquid influences he specification of system components. 'Superscript numbers efer o References at he nd of each chapter.

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2-2.2 VANE U MP S 2-2.2.1 Unbalanced Vane Pumps

Vane pumps onsist of a otor mounted n am - shaped housing. The rotor is provided with radial slots which ccommodate anes. A s he nternal ssembly rotates, he vanes are forced adially outward against the housing by centrifugal force sometimes assisted by

springs. Vane pumps can operate at speeds up to 2,000 rpm and are available in pressure ratings to 2,500 psi. Their imple onstruction esults n igh egree of reliability nd asy maintenance. They re elatively low in cost and exhibit long operating life partially due to he act hat an e wear s ccommodated y he radial motion of the anes. They av e omparatively high volumetric and overall efficiencies, and are available in a wide range of output ratings. Typical operating characteristic urves f an e pump re hown n Fig. -6 .

De

v

y g

m

In

we

h

o

i— — —t— |

Volumetric efficiency' J —1—1— 90

80 £

7 0 S 60 a

50 £,

40 § j

50 5

20 i

10

s ^"Over-oil efficiency

/

—

^ueiivery

jnpur ower

3 400 800 1200 1600 2C

Pressure (psi) KM

F i $ > . 2- 6 Typical Operat ing Characteristic Curves fo r a Vane Hydraulic P u m p

[From: Fluid Power ssue; Machine Design. Used y permission of Penton Publishing Co.]

Operating limitations of vane pumps are imposed by vane tip speed, bearing loads, and cavitation. The force exerted y he anes gainst he housing an e controlled by using dual vanes, i.e., two vanes in each slot. Each of the dual vanes has a smaller contact area than a ingle ane. he dual an e esign lso provides better seal etween he vanes an d he ousing.

Vane pumps exhibit a good tolerance to liquid contamination. They re enerally se d with petroleum- base or Military pecification hydraulic fluids in mobile perations nd ith etroleum r ire-resistant hydraulic luids n tationary pplications. Discharge pulsations can sometimes constitute a problem if high response is desired.

In he unbalanced an e pump, he otor nd am housing are eccentric (Fig. -7). The pump uction is generated in the region where the vanes begin to move outward. The liquid is carried around the rotor by the vanes, which form a seal with the housing and the end

plates, and it is discharged as the vanes are forced back into the otor slots by he eccentric ousing.

Springs-

Shaft /Tsf \ / ^ ^ j-'.'y v\ Afct

A \v/A

Vanes

Fig. 2 -7 . Unbalanced Vane Hydraulic Pu m p

[From: H . . Merrit, Hydraulic Control ystems. Used by permission of John iley nd ons]

Unbalanced vane pumps can be either fixed- or variable-displacement umps. n he ixed-displacement pump he otor-housing ccentricity s onstant nd, hence, he displacement olume s ixed. onstant volume of fluid is discharged during each revolution of the rotor. Variable displacement can be provided if the housing can be moved with espect o he rotor. This movement changes the eccentricity and, therefore, the displacement.

In ddition o liding anes, olling anes nd

swinging anes re lso vailable n nbalanced ane pumps Fig. -8). ach f hese ariations s ydro- statically unbalanced. This unbalance causes high bearing

(A)

B)

Fig. 2- 8. Vane-type ydraulic u m p s an d otors (A ) Roll ing Vane, nd (B) Swinging Vane

4 [From: H . . Merrit, Hydraulic Control ystems. Used by permission of John Wiley nd ons]

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loads an d generally limits the application of unbalanced vane pumps to perating pressures less than about 1,500 psi (Ref. 4). 2-2.2.2 Balanced Vane Pumps

Hydraulic balance is achieved in the balanced vane pump n which he otor s n an elliptic housing (Fig.

2-9).

his

onfiguration

reates

wo

iametrically- opposed isplacement olumes. he wo igh-pressure zones alance he orces n he otor haft. n many such units no springs re rovided to assist the outward motion of he anes. This condition restricts operation to peeds bove minimum t hich he entrifugal force s sufficient o hold the vanes against the housing. Other esigns utilize prings or start-up an d low-speed operation. alanced ane umps re ecessarily ixed- displacement machines.

2-2.3 PISTON U MPS The applications fo r which the piston pump is well-

suited are determined by its tw o principal advantages- high-pressure apability nd igh olumetric fficiency. n ddition, he piston pump an operate t speeds over 2,000 rpm; s available in a wide range of output atings; nd rovides ompact, ightweight unit fo r high power applications, low noise level when flow path s linear, nd better system conomy n he higher power anges above 0 p) .

Piston umps re lassified y he otion f he piston elative o he rive haft. here re hree categories-axial, adial, or otating.

R O T O R DISCHARGE P O RT

B

SUC TION P O RT

A

CASING

INLET OR OUTLET PORT

ARREL

ISTON

DRAIN P O RT

VANE

Fig. 2-?. Balanced Vane Hydraulic Pump

2-2.3.1 Axial-piston Pumps In the axial-piston pump, rotary shaft motion is con-

verted o axial eciprocating motion which rives the piston. Most xial-piston pumps re multi-piston e- signs nd tilize check alves or port lates to direct liquid flow from inlet to discharge. Output can be controlled y anual, echanical, r pressure-compensated controls. An axial-piston pump is shown in Fig. 2-10. Rotary drive motion s converted o reciprocating, axial piston motion by means of the thrust cam, or wobble late, ounted n he rive haft. ariable- displacement volume is provided by the internal alv- ing rrangement. xial-piston umps re vailable with output atings of over 00 gpm, nd some types are ated t ressures bove ,000 psi.

KEEPER PLATE

PISTON S H O E

THRUST CAM

VALVE HEAD

BE ARING

VA LV E HEAD' SHAFT BEA RI N G

MOUNTING FLANGE

INLET OR OUTLET PORT BARREL BEARING

Fig. 2-10 . Axial-piston Hydraulic Pump [From: . E. Merrit,Hydraulic Control Systems?\Jsed by permission of John Wiley an d Sons.]

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— DIAPHRAGM ACTUATOR

DIAPHRAGM

2-3.1 LINEAR ACTUATORS

2-2.7

Fig. -16 . Typica l Diaphragm Pump

CONNECTION BETWEEN UMP A N D DRIVE MOTOR

The hysical onnection etween he ydraulic pump and its drive motor is no t technically a hydraulic component. owever, t s n mportant part of the hydraulic system, and in many cases, may be the weakest ink n he ower rain. here re umber of methods fo r coupling the drive motor output haft o the hydraulic pump input shaft. Some of the more common ethods re eys nd ins, lexible ouplings, universal joints, lutches, nd plines. The most re - quently se d onnector n ydraulic ystems s he spline.

Splines offer the advantage of being able to transmit the maximum oa d with he smallest oupling diameter. n addition, they are self-centering, tend to equally distribute the load, and are simple to manufacture with standard gear-cutting quipment. Their major isad- vantage is the problem of wear. Even the best designed splines are subject to relative motion of the parts nd are difficult o ubricate.

2-3 ACTUATORS

An actuator is a device fo r converting hydraulic energy o mechanical nergy, nd hus as unction opposite that of a pump. An actuator, or fluid motor, can e se d o produce inear, otary, or oscillatory motion.

A inear ctuator or hydraulic ylinder s luid motor that generates linear motion. Various types are widely used in hydraulic systems because of their high force capability, ease of speed control, an d high power output fo r a given size and weight. They are especially suitable fo r control systems due to their high mechani- ca l stiffness and speed of response.

2-3.1.1 Classification of Linear Actuators

The many types of linear actuators which are available give rise to several criteria fo r classification.

(1 ) otating or nonrotating: In a otating actuator the cylinder, rod, and piston can otate. n many p- plications, uch s n otary achine ools, his feature s ecessary o llow nrestricted motion of the piston od . Such an actuator is llustrated n ig. 2-17. n order to permit tationary ounting f he fluid onnections, otating eal s required.

The nonrotating linear actuator, in which the cylinder is no t free to otate, s the most widely se d fluid motor.

Fig. 2-17 . Rotat ing Linear Actuator [From: . C. Fitch, Fluid Power and Control Systems*. Used by permission of McGraw-Hill, Inc.]

(2 ) iston or plunger: The piston and rod assembly in iston-type inear ctuator erves o ivide he cylinder volume into two separate chambers. The piston nd ttached ealing evices provide he eal e- tween the tw o chambers. The rotating actuator shown in ig. -1 7 s a iston ctuator.

In a plunger-type there is no piston. The end of the reciprocating ro d erves as he working face (see Fig.

2-18). The only seal provided is at the point where the plunger asses hrough he nd of he ylinder. n external force is equired o move he lunger nto the cylinder.

Both ypes provide onger stroke nd permit he use of the ighest ressure.

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Fig. 2-18. Plunger-type Linear Actuator

[From: E. C. Fitch, Fluid Power and Control Systems. Used by permission of cGraw-Hill, nc.]

(3) od classification: Linear actuators can also be classified as to rod type. A cylinder with on e piston rod is termed a single-rod actuator. The actuators shown in Figs. 2-17 and 2-18 are single-rod actuators. A double- rod actuator has piston rods extending from both ends of the cylinder. A telescoping rod consists of a series of nested rods which provide a long extension (Fig. 2-19). Such ods are useful or applications requiring a on g stroke ut ith nly imited pace vailable or he unextended od . positional od s se d where he

stroke is split up into two or more portions. The cylinder can be ctuated to an y ne of the positions.

J AISE

LOW ER

Fig. 2-19. Telescoping Linear Actuator [From: Pippenger and Hicks, ndustrial Hydraulics. Used y permission of cGraw-Hill, nc.]

(4 ) ylinder action: The type of cylinder action s important n he pecification of linear actuators. An actuator can be single-acting or double-acting. The single-acting yp e an move he iston od n nly ne direction y he pplication of hydraulic ressure. A plunger-type ctuator, iscussed n ubparagraph - 3.1.1(2), s ingle-acting ctuator. n he ouble- acting actuator, liquid pressure can be applied to either side of the piston, thereby providing a hydraulic force in both directions (Fig. 2-20). Double-acting actuators are also shown in Figs. 2-17 and 2-19. Springs, external forces, or a combination of both can be used o assist return of the piston od or plunger.

DOUBLE-ACTING CIRCUIT

tTHRUST N BOTH 1RECTI0NSI

PACKED GLAND

Fig. 2-20. Double-act ing Linear Actuator 2

[From: Pippenger and Hicks, ndustrial Hydraulics. Used y permission of McGraw-Hill, nc.]

(5 ) ingle, tandem, and dual actuators.Yet another

means of actuator classification is its assembly. Assem- blies f ctuators an e esigned o obtain various types of cylinder operation. A tandem actuator is on e in which two or more piston and rod combinations are assembled as a rigid unit with all pistons mounted on a ingle od . ig . -2 1 hows tepped-tandem actuator-two pistons of different sizes mounted on on e rod. uch actuators can be designed o obtain, or ex - ample, ow-force, igh-speed ction ollowed y

high-force, low-speed action. Tandem pistons can also be designed to provide a large working area (and thus large orces or a given pressure) or a small ylinder diameter. The piston and rod assemblies of a dual actuator Fig. -22) re ot astened ogether s n he tandem actuator. In most dual actuator designs, a given piston acts on nother only in one direction. Tandem and ual ctuators re requently se d n ydropneumatic systems where air is used as the power source and hydraulic luid s se d or control.

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'/////4&///A

wzzz 7///M

Fig. 2-21 . Stepped-tandem Linear Actuator

[From: E. C. Fitch, Fluid Power and Control Systems.

Used y permission of McGraw-Hill, nc.]

W////£y//77?

X A &ZZ,

*--—>-

7/S//A V kl

Fig. 2-22 . Dual Linear Actuator


ports s he piston nears he nd of the troke Fig. 2-23). A cushion-plunger attached to the piston enters a ushion ylinder. This ushion plunger hen locks the discharge port and traps liquid beneath the piston. This liquid assists in the deceleration of the piston s it approaches the cylinder head. A check valve allows fluid to flow back into the cylinder at the start of the return troke. The ate of piston deceleration an e controlled y esigning he ushion lunger with proper taper. This taper then permits a gradual closing of the discharge ports.

2-3.1.2 Mounting Configuration

One of the advantageous features of linear actuators is the variety of ways in which they can be mounted in a ystem. everal ounting rrangements re llustrated in Fig. -24.

2-3.1.3 Kinematics of Linear Actuators

(6) ushioned or noncushioned ype: n oncush- ioned ctuators, o rovision s made or ontrolled acceleration r eceleration f he iston ssembly. Therefore, such units have speed and inertia limitations imposed at both ends of the stroke. Cushioned actuators re esigned o nable he kinetic nergy of the moving piston to be absorbed at the ends of the stroke and thereby reduce peak pressures and forces. Cushion- ing an e ccomplished y locking he ischarge

The nature of the force provided by a linear actuator depends on the kinematic linkage between the straight- line output of the cylinder and the point at which the force nd motion re tilized. ecause of the many alternatives in the design of the linkage, he linear actuator an e se d o produce otary or oscillatory motion s well s inear motion. he esultant er- satility of linear actuators is partially illustrated by the applications shown n ig. -25.

FLUID INLET AND OUTLET^

CUSHI ON

S E A L

PISTON FLUID INLET A ND O U T L E T R OD

S C R A P E R

H E A D

CYLINDER

BARREL

R O D PACKING

Fig. 2-23. Cushioned Double-act ing Linear Actuator 2

[From: Pippenger and Hicks, ndustrial Hydraulics. Used by permission of McGraw-Hill, nc.]

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®— ®

'— 1^ — *

SIDE OO T MO U N T l@

fljjjrjfj „, , .„l g; ij

CENTERLINE MO U N T

EN D FOOT MO U N T

IP (S I o m m SIDE FLUSH MO U N T m

p O a a

REAR FLANGE MO U N T

wri FR O N T FLANGE MO U N T

- . Ö 0 o Ö

o o o o o

rori u a - is o

3) to] u n n r j

J

3 o o

S Q U A RE EA R LA N G E MO U N T S Q U A RE FR O N T LANGE MO U N T

ol l-l CLEVIS MOUNT

0 © § > 3 ai®

FR O N T TRUNNION MOUNT' INTERMEDIATE TRUNNION VAIL ABL E

c © IS ) < s T ©

REAR TRUNNION MOUNT*

INTERMEDIATE TRUNNION VAIL ABL E

©

TI E OD S XTENDED OTH ND S

§

TIE OD S XTENDED EA R ND O N LY

JEM © fr a

TIE OD S XTENDED FRONT EN D O N LY

HLSi s HLBJT BASIC MO U N T DOUBLE-END CONST RUCT ION

AVA I L A B L E N A NY MO U N T

Fig. 2-24. Mount ing Arrangements fo r Linear Actua to rs

[From: Stewart nd torer, Fluid Power. Used by permission of Howard W. am s nd Co., nc.]

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'/////////,

1 st class ever 2 nd class ever

' 7/7/77777//

Toggle

Straight ine motion

in wo directions

V7777 0 Straight ine

thrust educed

7 7 7 , 777777777777?-

Straight us h

3rd lass ever

«

I Straight line

motion

multiplied M

>///////

Horizontal parallel otion

'/////// K',, //'////.

4 positive positions with two cylinders

Trammel

plate

Motion

transterred o a distant ooint

77/77/7//,

Practically continuous otary

motion

/////////

Engine barring

7777777

77777777

Fast otary motion using

steep screw nut

Fig. 2-25. Applications of Linear Actua to rs

[From: E. C. Fitch, Fluid Power and Control Systems. Used by permission of McGraw-Hill, nc.]

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2-3.2 ROTARY ACTUATORS OR MOTORS

As in the case of a linear actuator, the function of a rotary ctuator, or otary luid motor, s o onvert hydraulic energy into mechanical energy. Rotary motors are usually rated in terms of the theoretical torque developed per 00 psi of inlet or differential pressure. The actual running torque and the stalled torque may be rom 0 o 0 percent f he heoretical orque, depending on the type of motor. The running volumetric fficiency may ary rom bout 5 o 5 percent, again depending on the particular motor. The highest operating fficiency ccurs ear he ated orque and peed.

The desirable features of the various types of rotary motors include:

(1 ) he ability to suddenly start, top, nd reverse without motor damage

(2 ) he ability o operate as a pump for braking (3 ) higher horsepower-to-weight atio han ny

other conventional power source (4 ) n infinitely-variable speed range (5) he bility o operate hrough ero peed or

overrunning loads (6) he bility o ccommodate ontaminants n

the fluid. Rotary luid otors re ssentially otary umps

operating in reverse. The mechanical characteristics of a articular otary otor re early dentical ith those of the corresponding ump.

2-3.2.1 Gear Motors

Gear motors, ike gear pumps, an e lassified s external or internal gear units. Also ike gear pumps, they are fixed-displacement devices. External gear motors include the gear-on-gear units such as the spur gear motor. nternal gear motors nclude the crescent eal types and he gerotor-type nit.

(1 ) ear-on-gear motors: In the gear-on-gear motor, rotary motion is produced by the unbalanced hydraulic forces on the gear teeth which are exposed to the inlet pressure. An example is the spur gear motor which has the am e mechanical eatures s he pur gear pump shown in Fig. -2 . These units are applicable for peak operating pressures up to about ,500 ps i and are avail-

able with ated apacities p o 20 pm , maximum speeds of about ,000 pm, nd power atings up o approximately 0 p. Bearing oads generated by he hydraulic unbalance are high, s in he case with n- balanced gear pumps. Typical operating curves for spur gear motors are given n ig. -26.

0 200 400 600 800 1000 1200 1400 600 80 0 Speed (rpm)

Fig. 2-26. Typical Operat ing Characteristic Curves fo r a Spur Gear Hydraulic M o to r

[From: Fluid Power Issue; Machine Design. Used y permission of Penton Publishing Co.]

(2 ) rescent seal motors: The rescent eal motor

employs an inner and outer gear with a crescent-shaped seal separating the teeth during part of the revolution. Its operational features are the reverse of those of the crescent seal pump illustrated in Fig. -4 . Motor units of this type are suitable for high-speed, low-power operations at low-to-moderate pressure. Starting torque and running efficiencies are low. Typical operating curves for crescent ea l motors are shown n ig. -27.

200

15 0

— 10 0 Flov»,300psi

'Flow, 100 psi

Torque, OOpsi

6

4 00 80 0 1 2 0 0 6 0 0 2000 2400 2800 3200

Speed ( rpm)

Fig. 2-27. Typical perating haracteristic urves fo r a Crescent Seal Hydraul ic otor

[From: Fluid Power Issue; Machine Design. Used by permission of Penton Publishing Co.]

(3) erotor-type otors: The erotor otor se e Fig. -5 or corresponding pump) is suitable for high- speed operation nd xhibits elatively igh tarting- torque efficiency. It can be used for operating pressures up to about 2,000 psi. Volumetric efficiency is relatively

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low and leakage rates are high at most speeds. The cost of gerotor motors is relatively high in comparison with the other gear motors. The operating urves of Fig. 2-28 re typical of the gerotor motor.

600

5 00

4 00

300

200

100

Torque, 1500psi

Torque, QOOpsi

Flow,

Flow, lOOOpsi

F Flow, 200 psi vF lbw, 500psi

Torque, 500psi

Torque, 200psi

0 200 400 600 800 1000 1200 1400 1600 Speed rpm)

Fig. 2-28. Typical perating Characteristic Curves fo r Gerotor Hydrau l ic M o t o r

[From: Fluid Power ssue; Machine Design. Used by permission of Penton Publishing Co.]

2400

2000

1600

-o 1200

o 00

400

Torque, 2000 psi

Flow,500psi

Flow,1000psi

Torque, 500psi

60

45

90

30 ,T

0

00

00

20 0 1600 2000 2400

Speed (rpm)

Fig. 2-29. Typical perating Characteristic urves fo r a Vane Hydraulic M o t o r


2-3.2.3 Limited-rotation Motors

2-3.2.2 Vane Motors

Most an e motors re of the balanced-rotor ype because hydraulic unbalance causes arge radial bear-

ing loads which limit the use of unbalanced vane motors to low pressure operation and applications where weight nd pace onsiderations o not preclude he use of large, heavy bearings. Therefore, most vane motors have a mechanical configuration similar to that of the balanced vane pump shown in Fig. 2-9 and are thus fixed-displacement nits. o ccommodate tarting and low-speed operation, it is usually necessary to provide orce-in ddition o he entrifugal orce-to move the vane radially outward. Springs are commonly used for this urpose.

As with vane pumps, rolling and swinging vanes can also be used n an e motor design se e Fig. -8). The

overall running efficiencies of vane motors are typically 80 to 85 percent. They are available at rated powers up to approximately 25 hp , pressure ratings to about 2 ,- 500 psi, nd maximum speeds of approximately 3,000 rpm. Characteristic operating curves of a vane motor are shown in ig . -29.

Limited-rotation motors, or otary ctuators, provide n oscillating ower output. ariety of uch units s available, ll of which onsist of on e or more fluid hambers nd movable urface gainst which the fluid pressure is applied. Both vane-type and piston- type motors can be used to obtain an oscillatory output.

(1 ) an e type: There are two types of limited-rotation vane motors, the single-vane and the double-vane. The single-vane unit consists of a cylindrical housing, a haft with single ane, barrier which imits he vane rotation, and end pieces which support the shaft(Fig. -30). High-pressure liquid enters on on e side of the ane, orcing the vane o rotate to the barrier. A rotation of approximately 280 degcan be obtained with the single-vane unit. In the double-vane unit, the high- pressure fluid enters on on e side of a vane and is ported through the shaft to the corresponding side of the other vane (Fig. 2-31). A rotation of about 100 de g is possible with he double-vane motor. n both he double- nd the single-vane units, seals are maintained between the rotor and the barriers and between the vanes and the housing. imited-rotation an e motors re vailable with torque outputs ranging from less than 0 in.-lb at about 0 ps i to early 50,000 in.-lb at ,000 psi.

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CYLINDER PISTON

Fig. 2-30. Typica l Single-vane Actuator

[From: Fluid Power ssue; Machine Design. Used by permission of Penton ublishing Co.]

Shoft an d vane^^^-, assemblyv -jT7^

—_^~ ^Stationary TlV c barrier

Seal \ ^—J

Fig. 2-31 . Typical Double-vane Actuator

[From: Fluid Power ssue; achine Design. Used by permission of Penton Publishing Co.]

(2 ) iston ype: Piston-driven ctuators are available n everal onfigurations esigned o produce n oscillating output. The helix-spline unit employs a shaft with a elical screw which asses through he piston (Fig. 2-32). A guide rod prevents rotation of the piston.

Rotations of greater than 360 de g are possible. A self- locking helix angle prevents rotation when an external torque is applied. The piston-rack unit consists of tw o or more pistons which provide the rack fo r a rack-and- pinion system (Fig. 2-33). Many variations of the latter design re available.

/ OUT P UT SHAFT

-GUIDE ROD

Fig. 2-32 . Helix spline Rotary Actuator


PISTON SEAL\ PISTON

P I N I O N GEAR' PISTON'

O I L - F I L L E D H A M B E R

Fig. 2-33 . Piston-rack Rotary Actuator 2

[From: Pippenger and Hicks, ndustrial Hydraulics. Used y permission of McGraw-Hill, nc.]

2-3.2.4 Piston Motors

Piston motors which generate ontinuous otary output motion (as opposed to linear actuators) can be classified in terms of the piston motion-axial, radial, or rotary. They can be fixed- or variable-displacement de - vices. They can operate at high pressures and have high volumetric fficiencies. The power-to-weight atio of piston motors is not s favorable as hat of gear and vane motors, but piston units are available with power

outputs greater than 00 hp . Relative cost per horsepower is high. (1 ) xial-piston type: The operation of an axial-pis-

ton motor s ssentially he same as hat of an xial- piston pump except for the direction of flow (see Fig. 2-10). The high-pressure liquid introduced through the

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motor nlet orces he iston ssembly gainst he thrust cam or wobble plate. The angular application of this force causes the plate to rotate and this rotation is transmitted by the shaft. The displacement can be varied by changing the angle of the thrust cam. Leakage is ow under both unning and talled onditions.

(2 ) adial-piston ype: The adial-piston motor s

also ssentially ts pump counterpart operating n e- verse Fig. -11). iquid nters he iston hamber through a central intle. The piston is forced adially outward gainst he thrust ing, hereby producing force angent o he iston hamber. he esulting torque causes the shaft to rotate. This motor type exhibits ery igh olumetric fficiencies nd igh torque, and is well-suited for low-speed application be - cause of the small mass of the rotating parts.

(3) otary-piston ype: The otary-piston motor s the same as the rotary-piston pump except fo r the flow direction. he ump as escribed n ar. -2.3.3. Units re vailable with ating of up o 00 hp t

2,800 rpm with a maximum torque of over 20,000 in.- lb. Weight and space-to-power ratios are high, and cost per horsepower is sually igh.

2-3.3 FLUID TRANSMISSIONS

A fluid transmission is a device which converts mechanical power into fluid power, transports this power, and hen onverts t ac k nto echanical ower. Therefore, the circuit consists of some suitable combination of pump and motor with the necessary piping. The transmission characteristics depend on the pump and motor combination. The various possible combinations are outlined in the paragraphs which follow. As- sumptions made re hat he pump outlet nd motor inlet pressure are the same; a constant output pressure is maintained on variable-displacement pumps; and the pump speed is constant. Fixed-displacement pumps are assumed o have relief valves.

(1 ) ixed-displacement pump and motor: The torque and horsepower of the pump are functions of the pressure but the speed nd flow ate are usually constant. Below the relief-valve setting, he motor torque and horsepower vary with pressure while the speed and flow ate re onstant. t r bove he elief-valve pressure, the motor torque is constant, but motor speed and low ate re unctions of the volume low ate through the relief valve. The resulting transmission exhibits onstant peed with ariable orque and orsepower elow he elief alve pressure, nd onstant torque ith ariable peed nd orsepower t higher ressures.

(2 ) ixed-displacement pump and variable-displacement motor: The pump operates as described n par. 2-3.3(1). The torque of the motor varies inversely with speed. Motor flow rate is a function of both displacement and relief-valve flow. The transmission produces constant orsepower nd orque hich aries with peed.

(3 )

ariable-displacement pump and fixed-displacement motor: The pump pressure nd peed re on - stant, but the torque and horsepower vary. The motor pressure and torque are constant while the speed and horsepower vary. The resulting transmission as constant orque. The horsepower varies with speed.

(4 ) ariable-displacement pump nd otor: The pump operates s n he preceding ase. he motor torque and speed are inverse functions of the displacement. The torque and horsepower transmitted by he system can e constant or variable.

2-4 INTENSIFIERS

A liquid intensifier-used only in single cylinder applications-is a device used to compress the liquid by a pressure greater than the system pressure generated by the primary pump. This is accomplished by using different piston working areas to boost the pressure. The increase in pressure obtained n he simple intensifier shown in Fig. 2-34 is directly related to the area ratio of the pistons. The high-pressure piston is attached to the same rod as the larger low-pressure piston. When the control valve is in the neutral position, he liquid, which is at system pressure, is directed to a reservoir. If the left solenoid is actuated, fluid is introduced to the rod side of the low-pressure piston and into the chamber on the downstream side of the high-pressure piston. The piston assembly moves to the right, eturning the fluid n he low-pressure chamber to reservoir. The intensifier is then ready fo r a working stroke. When the right solenoid is energized, fluid is introduced into the low-pressure chamber. The piston assembly is driven to the eft, ompressing he luid n he igh-pressure chamber. Because of the reciprocating pumping action, the intensifier produces a pulsating high-pressure flow. The high-pressure flow rate is less than the system flow rate y he am e atio s hat of system pressure o boosted ressure.

In circuits which require high-volume, low-pressure flows-as well as smaller high-pressure flow over short periods-the fluid intensifier offers an economic alterna- tive o he ecessity of providing two primary power sources.The ntensifier as everal dditional dvantages. A ow power nput an e se d o maintain

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CYLINDER

HIGH P R E S S U R E

, CYLI NDER

LIMIT WITCH G

HIGH-PISTON

(AREA=O.I H A T OF O W P R E S S U R E

P IS TON)

LIMIT SWITCH

-4fc ^

-D

rs\MT ffi

DIRECTIONAL

CONTROL

VALVE

Xl^Tsön

LOW- PRESSURE

PISTON '(AREA=10x

T H AT F H E

HI GH- PRESSURE

PISTON)

Fig. 2-34 . Diagram of a Hydraulic Intensifier Circuit 2


high pressure for a period of time. The high-pressure regions of the circuit can be localized, thereby reducing the amount of high-pressure piping and the number of high-pressure eals equired. ecause of the eal e- tween the high- and low-pressure chambers, the intensifier can be operated with a liquid different from that used in the high-pressure part of the circuit. ince no heat s generated while tatic pressure s maintained and little heat is generated during rapid cycling, nly small eserves of oil re required.

2-5 RESERVOIRS

2-5.1 FUNCTION

Reservoirs not only provide a storage facility for the liquid ut an lso erve o eparate ntrained ir, remove contaminants, and issipate eat rom he liquid. hus, long ith eat xchangers nd ilters, he eservoir s n mportant iquid-conditioning omponent.

must be determined. The sizeand configuration depend on many factors. The minimum required capacity can vary from one to three times the volumetric ating of the pump in gallons per minute. The reservoir should be sufficiently large to accommodate the liquid necessary to fill all system components if the liquid drains back to the reservoir. It should have sufficient capacity to maintain a liquid supply at the pump suction at al l times. Sufficient liquid should be in the system to prevent he ormation of vortices t he pump uction. Reservoir volume should be provided to allow time for

solid contaminants and gases to separate from the liquid. his actor lso epends n oth he haracteristics of the liquid and filtering system design. Ade- quate space above the liquid level should be provided to accommodate thermal expansion of the liquid. If the reservoir erves s he primary means of dissipating heat from the liquid, t should be large enough to accommodate the required cooling. In some applications, the iquid n he eservoir s ntermittently se d s heat ink. t s hen ecessary o provide torage or enough iquid o ive he esired heat apacity. or operation n old nvironments excessive cooling can also be avoided by proper reservoir apacities.

2-5.2 CAPACITY

Even before the conditioning functions of the reservoir re onsidered n esign, he necessary apacity

2-18

2-5.3 DESIGN

There are three basic reservoir arrangements-separate, integral, and dual-purpose. Separate reservoirs are

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commonly used in large stationary systems where space and weight are not important considerations. ntegral reservoirs are spaces provided within the hydraulic system-such s iping, ubular tructural embers, r machine ases. uch esign inimizes pace nd weight equirements. owever, he torage of a hot liquid within the system can sometimes cause thermal

distortion of precision omponents. f the iquid an serve s both ubricant nd hydraulic luid, n- dividual eservoirs re not equired. The eservoir n which such a liquid is stored is termed a dual-purpose reservoir. or xample, he ase hich ouses he transmission in some vehicles, and which thus contains the transmission lubricant, also serves as the hydraulic fluid eservoir. n uch pplications t s, f course, necessary that the liquid function satisfactorily both as a ubricant nd s hydraulic luid. Also, ince he liquid absorbs heat from tw o sources, it may be difficult to provide adequate cooling.

Many of the guidelines which assist in the design of reservoirs are the same regardless of the reservoir

type.

Baffles should be provided between the suction line and the luid-return ines o prevent ontinual se of the same liquid. Baffles also reduce the liquid velocity and thereby facilitate the settling of solid contaminants and deaeration of the liquid.

Lines which return liquid to the reservoir should be well below the liquid level o minimize aeration. uction ines hould lso erminate elow he minimum liquid level, but the inlet should be at least 1-1/2 pipe diameters bove he ank loor. f he uction ine strainer is not sufficiently beneath the liquid level at all times, a vortex could form and permit air to enter the suction line. Gravity drains from seal cavities should be separate from the liquid return lines and should enter the eservoir above the liquid evel.

Ample provision ust e ad e or raining nd cleaning. Liquid-level indicators should be provided to indicate the maximum and minimum allowable liquid levels. An air breather and filter allow ir to enter or leave the reservoir as the liquid level fluctuates. om e reservoirs are pressurized o assist pump suction.

2-6 FILTERS

The ability to keep the liquid clean is a very impor-

tant actor n he ong-term operation of a hydraulic system. To minimize contaminant levels, foreign matter should be prevented from entering the system; conditions conducive to contaminant formation within the system should be avoided; and filters should be used to remove contaminants.

Filters are rated in terms of the degree of filtration. The ratings are usually expressed in microns (1 micron = .937 x 10 n.). If a filter can remove 98 percent of the particles of a certain size or larger, then this particle size, expressed in microns, is termed the nominal filtration value. The absolute filtration value is the size of the smallest article hich he ilter an ompletely

remove from the flow. Filters are usually rated in terms of both nominal nd bsolute alues. t s ommon practice o pecify ilters with n bsolute iltration value qual o ne-half f he mallest learance or olerance n he omponents hich he ilter must rotect.

2-6.1 CLASSIFICATION OF FILTERS

Filters are classifiedaccording to the filter media, the configuration, or the filtering method. The filter media can be either the surface-type or the depth-type. The surface-type filtering media contain numerous orifices of relatively uniform size. Particles larger than the orifice size are trapped on the surface of the media. Depth- type media have long tortuous paths through which the liquid must flow. Particles larger than the cross section of hese low aths re etained xcept erhaps or some particles which are larger in only one dimension. Wire mesh s n xample of a urface ilter medium. Depth media nclude intered metal powders nd i- brous materials such as paper, felt, glass, and cellulose. Classification by filter media is closely related to classification y iltering method, which s discussed n par. 2-6.2.

There re ive asic ilter onfigurations se e ig. 2-35). The T-type ilter s he most widely se d unit because t s ompact nd asy o lean r eplace. By-pass eliefs nd ressure-difference ndicators re frequently ncorporated o etermine hen ilter is clogged.

2-6.2 FILTERING METHODS

There are three basic physical mechanisms by which filters an emove ontaminants rom ydraulic fluid-mechanical, adsorbent, and absorbent. The filtering methods ometimes function n ombination.

2-6.2.1 Mechanical ilters

In a mechanical filter, particles are removed from the hydraulic luid y irtue f heir nability o ass

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T-type Po t type Y-type

In-line type

570 gp m

FF- 3-

600

gp m

Wash yp e 30 gp m

Fig. 2-35 . Basic Configurat ions of Filter Assemblies 4

[From: H . E. Merrit, Hydraulic Control Systems . Used y permission of John iley nd ons]

through the multitude of small holes or orifices in the filter. Metal or fabric screens are commonly used as the filter media. The disk-type filter shown in Fig. -36 is also a mechanical filter. The size of particles which can be emoved y his ilter epends n he pacing

Fig. 2-36. Hydraulic Fluid Filter With Disk-type Filter Elements

2 [From: Pippenger and Hicks, ndustrial Hydraulics Used y permission of cGraw-Hill, nc.]

between he isks. The filter an be cleaned while in service by revolving the central shaft to which alternate disks re eyed. The tationary lements hen ct s wipers. ire-screen echanical ilters an lso e cleaned if care is taken not to force contaminant particles inside or through he elements.

2-6.2.2 Adsorbent Filters

Adsorption is the phenomenon by which particles of on e material tend to adhere to solid or liquid surfaces. The filter medium in an adsorbent-type filter is finely divided to present maximum surface area to the flow. Materials used in the filter elements include activated clay, charcoal, fuller's earth, chemically treated paper, and bone black. The flow passages of the filter can also mechanically remove contaminants. One disadvantage of the adsorbent filter is the tendency to remove certain additives in the hydraulic fluid. Hence, it is not usually recommended fo r service with fluids which contain ad - ditives. Many adsorbent filter housings are designed to accommodate ither n dsorbent ilter lement or mechanical filter lement.

2-6.2.3 Absorbent Filters

A porous, permeable medium is used as an element in n bsorbent ilter. lement aterials nclude diatomaceous earth, wood, pulp, asbestos, paper, various textiles, nd a variety of other substances. A s the

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hydraulic fluid passes through the filter medium, contaminants are trapped by absorption. Water and water- soluble contaminants can be removed by some absorbent filters. The size of solid contaminant which can be filtered depends upon the permeability and porosity of the filter element.

2-6.3 HYDRAULIC FLUID-FILTER COMPATIBILITY

The hydraulic fluid filter must not be affected by the hydraulic luid t ny operating ondition. Also, he filter must not have an y effect on the hydraulic fluid- such as removing additives in the liquid. Filter compatibility is not often a problem with pure mechanical-type filters. n his ase t s nly ecessary o se a filter element ade f materials usually etal) hat re compatible with the particular hydraulic fluid. This is not he case, owever, when absorbent- or adsorbent- type ilters re sed. n ddition o heir mechanical filtering action, these filters also have a chemical filtering ction. The chemical ction may esult n the re - moval of additives as well as impurities and contaminants. ecause dditives re sually ncluded o improve properties of the liquid, heir removal is not desirable. pecial onsideration must e iven o he use of these ilters when he hydraulic luid s not straight unmodified base stock.

2-6.4 FILTER RESSURE DROP

The nfluence of pressure drop n ilter election involves a compromise between tw o conflicting factors. In order to filter small particles from a hydraulic fluid, the size of the filter assages must e small, nd this results in high pressure drop. However, if the pressure drop is too igh, ontaminant particles an penetrate into or hrough he ilter lement. pressure drop greater than 2 or 5 si is usually sufficient to force the ontaminants ommonly ound n hydraulic ys - tems hrough a typical filter.

The pressure drop is a function of contaminant particle size, the fineness of the filter medium, the ability of the particle to resist the drag forces created by the flow, the rate at which particles accumulate in the filter, and the mechanical strength of the filter element. The pressure differential which ca n be tolerated across a filter also depends upon the location of the filter in the system. Allowable pressure drop is also an important factor in establishing the cleaning and service schedule of a filter.

2-6.5 REPLACEMENT OR CLEANING INTERVALS

Two approaches ca n be made to establish a maintenance program or hydraulic luid ilters. f nstruments are provided to monitor filter operation, replacement or cleaning can be based upon the data obtained

from these measurements. If no such data

are available, it s necessary o stablish ystematic maintenance

program hich pecifies he perating ntervals or each ilter.

Pippenger and Hicks (Ref. ) present he following guidelines n hich o ase ilter aintenance schedule:

(1 ) rovide instruments to monitor filter saturation and ndicate cleaning or replacement equirements

(2 ) tress the importance of the filters in the system operating procedure y nstructing ll operating nd maintenance personnel in the filter locations, functions, an d service schedules

(3 )

stablish ervice rocedures hich inimize downtime and fluid oss (4) aintain records of filter performance and use

these to establish atisfactory filter service times (5) valuate filter performance to determine if dif-

ferent ilters might mprove the system operation.

2-7 ACCUMULATORS

An accumulator is a device which can store hydraulic energy. t is useful in intermittent operation of hy-

draulic machines when the accumulator can be charged at a low flow rate during the idle portion of the cycle of the driven machine. Accumulators can be used or pressure ompensation, ulse damping, eakage om - pensation, mergency ower, uxiliary pressure, nd several other pplications. he y an lso e se d o apply pressure across a physical boundary between two liquids without contact or mixing of the liquids. This feature permits the pressurization of hazardous fluids, e.g., a volatile liquid, by means of a second liquid which can be safely pumped.

2-7.1 ACCUMULATOR LOADING

Accumulators are classified in terms of the manner in which he load is applied. This s the major factor which influences design. Accumulators can be weight- loaded, pring-loaded, or pneumatic-loaded.

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2-7.1.1 Weight-loaded Accumulators

The weight-loaded accumulator consists of a piston mounted vertically in a cylinder (Fig. 2-37). The piston rod or plunger is oaded with weights which provide potential energy to compress the fluid. This accumulator roduces irtually onstant ressure t ll luid levels. However, weight-loaded accumulators are very heavy and expensive. They also do not respond quickly to hanges n he system demand. For hese easons, they re not ften se d in modern hydraulic systems.

WEIGHT W

CYLINDER

PACKING RA M

DI AM ETER —>

P R E S S U R IZ E D

-;-;-2 FLUID :-i-z-

CHECK ALVE V

FROM OURCE

OF LUID UNDER R E S S U R E

CYLINDER

Sg:----------r--Hy—TO OR K LOAD

Fig. 2-37- W eight-loaded Hydraul ic Accumula to r 2

[From: Pippenger and Hicks, ndustrial Hydraulics.

Used by permission of McGraw-Hill, nc.]

2-7.1.2 Spring-loaded Accumulators

An accumulator in which the compression energy is supplied by a spring is shown in Fig. 2-38. The pressure varies with he mount of luid n he ccumulator since he pring orce depends n displacement. l- though uch pring-loaded evices re asy o maintain, they are relatively bulky and costly. Most applications are fo r low-volume, ow-pressure systems.

2-7.1.3 Pneumatic-loaded Accumulators

There are tw o types of pneumatic-loaded accumulators. In on e type, the gas which provides the load is in

Fig. 2-38 . Spring-loaded Hydraulic Accumula to r


direct contact with the hydraulic fluid, whereas in the second type they re separated by a diaphragm, bladder, or piston.

(1 ) onseparated-type: ressurization n on - separated, pneumatic-loaded ccumulator s chieved by ntroducing ressurizing as nto ontainer above the liquid level. The pressurized storage vessel is

a simple example of this type. Limit switches, which are actuated by liquid level, are usually used to limit pressure. This type can accommodate large liquid volumes, but eration of the liquid ften precludes their use in hydraulic systems. Fig. 2-39 shows a diagram of a nonseparated pneumatic accumulator in circuit.

Accumulator,

Shop air Relief alve

C h evel switch

Low evel switch

Fig. 2-39.

T o f switch Closing

valve

Nonseparated Pneumatic-loaded Hydrau- lic Accumulator

[From: Fluid Power Issue; Machine Design. Used y permission of Penton Publishing Co.]

(2 ) eparated-type: eration n he neumatic- loaded ccumulator can be eliminated by providing a barrier between the pressurizing gas and the hydraulic

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fluid. iaphragms, ladders, r pistons re se d s barriers. A diaphragm-type ccumulator s hown n Fig. -40. The pherical essel s eparated nto wo compartments by a flexible diaphragm. One compart- ment s onnected o he ydraulic ystem nd he other to the high-pressure gas system. n most designs a spring-loaded, normally-open check valve or a screen

is provided at the liquid connection o prevent extru- sion of the diaphragm into the liquid line when the fluid is discharged.

T o ressure manifold

Screen

A ir alve

Fig. 2-40 Diaphragm-type Pneumatic- loaded Hydrau- lic Accumula to r

[From: E. ewis, Design of Hydraulic Control Systems.


A ree-floating iston an lso erve s arrier between he as and hydraulic luid Fig. -42). This type is less effective as a pulsation damper than is the bladder-type.

Fluid port-

Air ort-

Air alve

Accumulator harged ith ir nd luid ressure Piston hown n "bolanced" position

Hydraulic luid ischarged Piston "bottomed"against luid ort ead

Fluid

ir

Fig. 2-42. Free-floating Piston, Pneumatic- loaded Hydrau l ic Accumula to r

[From: E. ewis, Design of Hydraulic Control Systems. Used y permission of McGraw-Hill, nc.]

The eparated, pneumatic-loaded ccumulators re the most commonly used. They are small, lightweight, and an be mounted in an y position.

The bladder-type accumulator usually has a bladder inside a cylindrical shell with pressurized gas inside the bladder nd he hydraulic luid etween he bladder

and he housing Fig. -41). he bladder s sually constructed with the thinnest wall near the gas port. t thus expands at the top first and then along the walls, forcing he liquid out hrough the poppet alve. This design can be used for ratios of maximum to minimum pressure p o bout o nd, because of the ow inertia of the bladder, it is especially suitable for damping pulsations.

Ai r

il

Fig. 2 -41 . Bladder-type Pneumatic- loaded Hydrau- lic Accumula to r

[From: Fluid Power ssue; Machine Design. Used y permission of Penton Publishing Co.]

2-7.2 ACCUMULATOR SELECTION CONSIDERATIONS

The factors which enter into the selection or specification of accumulators depend on the desired function of the unit in he hydraulic system. The compression and xpansion f he as n neumatic-loaded c- cumulators are governed by the laws of gas dynamics. If discharge im e s apid less han bout in or most pplications), he xpansion process an e s- sumed to be adiabatic. Isothermal relations can be used for compression f the process is low.

The precharge pressure should beselected so that use is ade of all iquid n he ccumulator. he otal volume equired s he um f he ompressed as volume nd the volume of the liquid required by he system. The compressed gas volume is a function of the charge nd ischarge imes. he equired iquid volume must be determined from the desired performance of the accumulator. Empirical relations are available o determine he iquid olume equired o ffectively damp pump pressure surges or to suppress line

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shock caused by sudden liquid deceleration. When used to ecrease ine hock, he ccumulator hould e located near the source of shock.

Accumulator systems, if they are used to store liquid energy, are often separated from the power source by a check valve. If the leakage is negligible, temperature fluctuations can induce gas-volume changes which, in turn, could generate harmful pressure variations in the system. f the hydraulic system must operate throughout a range of temperatures, it is necessary to conduct a P- V-T analysis of al l locked accumulator circuits. The accumulator s precharged o pressure P g with as which ccupies he otal ccumulator olume. Then liquid at pressure Pfand temperature TB\ s introduced into the accumulator, compressing the gas to a volume Vg, with a liquid-gas temperature of Ta', Changing the liquid-gas temperature to T' does not result in a significant volume change but rather a change in accumulator pressure o g. t s his pressure which ould harm components or cause system malfunctions. Using the gas ompressibility actor g , efined s g

PV/NR°R, the pressures and temperatures at constant volume are related y

V« P'

7' T' ,g l a

(2-1)

Since both P g and Zg are unknown in this relation, trial-and-error method, using appropriate values from compressibility harts, must e se d o valuate he pressure change which results from a specified temperature change.

2-8 VALVES

Valves are used in hydraulic circuits to control pressure, flow direction, or flow rate. They utilize mechanical motion to control the distribution of hydraulic energy within he system.

2-8.1.1 Sliding-spool Valves

The sliding-spool alve is the most requently se d type in hydraulic systems. Fig. 2-43 illustrates the major onfigurations hich mploy he liding pool. These are classified in terms of the type of center which exists when the spool is in the neutral position. Other factors used in spool-valve classification are the number of ways in which flow can traverse the valve and the number of lands n he spool.

2-8.1.2 Seating Valves

The wo-jet lapper alve shown n ig. -44 s n example of a seating valve. Such devices are frequently used as the first stage in a two-stage servovalve (seepar. 2-8.3.6). hey re imited o ow-power pplications because of their elatively igh eakage ates. Toler- ances re not s lose on lapper alves s n pool valves and, hence, they are less expensive and less sensi-

tive to fluid contamination. Poppet alves Fig. -45) lso se he eating on - figuration. owever, hey re ssentially wo-way valves nd, herefore, re imited o pplications n which low eversal is not equired, .g., elief valves and check alves.

2-8.1.3 Flow-dividing Valves

The jet-pipe valve, Fig. 2-46, utilizes the flow-dividing configuration. n he arrangement shown, low s metered into tw o receivers by a nozzle. Equal areas of the two receivers are covered by the nozzle. The resulting forces provide hydraulic balance. The principal ad - vantage of the jet-pipe valve is its ability to accommodate elatively igh evels f luid ontamination. However, its characteristics are difficult to predict, and it exhibits slow response and large null flow. Like the flapper valve, he jet-pipe valve is more effective s a pilot stage than as a main second stage in servovalves. This s particularly he ase f high pressure ain s required at igh flow rates.

2-8.1 VALVE CONFIGURATIONS

A valve directs the distribution of hydraulic energy within a system by the operation of a mechanical element n he alve. There re hree onfigurations or modes of operation-sliding, seating, and flow dividing.

2-8.2 VALVE TYPES

Valves re lassified ccording to heir function n the hydraulic system. These basic ypes are pressure- control valves, directional-control valves, and volume- control alves. Most alves an e egarded s ome combination of these basic types.

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Fig. 2-46 . et-pipe Flow-dividing Valve


2-8.2.1 Pressure-control Valves

A pressure-control valve either limits the pressure in various circuit components or changes the direction of al l or part of the flow when he pressure at certain point eaches pecified evel. uch ontrols re i- rectly r ndirectly ctuated by some system-pressure level.

(1 ) elief valves: A relief valve limits the maximum pressure that can be applied to the part of the system to which t is connected. t acts as an orifice between the pressurized egion nd econdary egion t lower pressure. n most applications, the relief valve is closed until the pressure attains a specified value. Then the flow through the valve increases as the system pressure rises until the entire system flow is vented to the low-pressure region. As the system pressure decreases, the valve closes.

There are three types of relief valves-direct-acting, differential, nd ilot. An djustable spring load pro-

vides he ressure etting n ll hree ypes. n he direct-acting pressure-relief valve, the system pressure acts directly n he pring Fig. -47). his ype s usually se d on ow-pressure systems or when elief- valve conditions are expected only rarely. Valve chatter or pressure luctuations re ften roblem, hich results from the fact that the springs required in such a valve are heavy. The differential relief valve shown in Fig. 2-48 can be constructed with a much lighter spring than the direct-acting type because the system pressure acts over only a differential area. n the pilot-operated relief alve, ressurized iquid s sed o ssist he spring Fig. -49). The liquid asses rom he supply line through a restricted passage to a control chamber where it acts on a plunger to add to the spring force. The force is limited by a small-capacity, direct-acting pilot elief alve. he ilot-operated elief alve is sually pecified or ystems hich equire re - quent relieving.

Fig. 2-47. Direct-act ing Pressure-rel ief Valve


Drain

Pressure input

^Differential shoulder area

Fig. 2-48. Differential Pressure-rel ief Valve

[From: Fluid Power Handbook. Used by permission of Industrial Publishing Co.]

(2 ) nloading valves: An unloading valve provides a vent o ow-pressure rea when pecified pilot pressure is applied (Fig. -50). The signal is provided by an xternal source. These valves can be applied in

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weight of a vertically mounted piston from causing the piston to descend. The spring setting produces a back pressure on the piston which counterbalances the force of gravity.

(6) egulator alves: The unction of on e ype of pressure-regulator valve, or pressure-reducing valve, is to supply a prescribed reduced outlet pressure regard-

less of he

pressure

t

he alve nlet. n

his ype, shown n ig. -54, he outlet ressure s alanced against a spring. A drop in downstream pressure allows the spring to increase the valve opening nd ncrease the downstream pressure. In the second type of regula-tor valve, the inlet pressure is balanced against both the spring and the outlet pressure (Fig. -55). The spring setting then determines the amount of pressure reduction across the valve. Hence, this type is used to maintain a fixed pressure differential across the valve fo r all values of upstream ressure.

Fig. 2-54. ressure Reducing Valve (Constant Down- stream Pressure)


Fig. 2 -56 . Pressure Switch


(8) ydraulic fuzes: A hydraulic uz e mploys frangible diaphragm or similar device which fractures at a preset pressure. It can thus be used as a substitute for, or n onjunction with, pressure control alve. Hydraulic fuzes can be used with safety valves to prevent hydraulic fluid loss under normal operating conditions. hey sually o ot av e utomatic eset capabilities. t s ecessary o anually eplace he diaphragm f the hydraulic fuze is actuated.

2-8.2.2 Directional-control Valves

V///////ZZZX

m V////)//////7A

A UZZZZZZZZZZZZZZ.

Fig. 2-55. Pressure Regulat ing Valve (Constant Pres- sure Differential)

[From: E. C. Fitch, Fluid Power and Control Systems '. Used by permission of McGraw-Hill, nc.]

(7) ressure switch:When a pressure-actuated electric ignal s equired or ystem ontrol, pressure switch s se d Fig. -56). The ystem pressure cts against an adjustable spring used to preset the switch. When the pressure reaches the specified value, the mi- croswitch is actuated. The signal can be used to actuate a variety of control lements. Although he pressure switch is not a valve, it is a valuable control element in valving systems.

2-28

Controlling where nd when he hydraulic luid s delivered to various parts of the system is the function of directional-control valves. These valves are used to

control he operation of actuators. (1 ) heck alves: The imple heck alve permits

free flow in one direction and blocks flow in the reverse direction (Fig. 2-57). When flow is in the normal direction, the liquid pressure acts against the spring tension to old he poppet off the seat. When low stops, he spring eats he poppet nd iquid cannot ass in he reverse irection. heck alves an lso e ilot- operated (Fig. -58). n such a unit, low can proceed freely in one direction, but reversed flow depends upon the pilot actuation. Pilot-operated check valves can be either normally losed or normally open.

(2 ) osition alves: The unction f he osition

valve is to control the introduction of liquid to the lines of the system. When he valve is operated, he liquid lines within it are shifted. Position valves are classified in terms of the number of valve positions and the number f iquid orts, .g., our-way, hree-position alve.

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Fig. 2-57 . Poppet - type Check Valve

[From: E. C. Fitch,

Fluid

Power and

Control Systems.


/Pilot onnection

Jf - 1\

Drain

Fig. 2-58. Pilot-operated Check Valve


Two-way valves are generally shut-off valves. There are several types-spool, poppet, plug, ball, and rotary. Unlike a check valve, the two-way valve can block flow in both directions.

Three-way nd our-way alves re vailable with either tw o or three positions and with open or closed centers. There are six basic types-spool, poppet, packed plunger, plug, plate, and rotary. A three-way valve can be used, or example, o control a single-acting linear actuator. One of the many applications of a four-way valve s ontrol f double-acting ctuators. pecial valves are available in ive- nd ix-way ersions.

Several spool-valve configurations are shown in Fig. 2-43. The function and pplication of a specific alve are etermined y he pool onfiguration nd he method f ctuation. or xample, hree-position valvecan be used to isolate an actuator from the circuit,

to provide a bypass to the reservoir around the actuator, or to hold an actuator in an intermediate position. The open-center configuration, when centered, permits the liquid to flow back to the reservoir with little pressure drop. In the closed-center configuration, the ports are locked he n he alve s entered. he am e source an hen e se d or other alves n arallel.

When the tandem-center configuration is centered, the downstream ports re locked; but iquid an reely flow o he eservoir nd , ence, he pump oe s ot necessarily have to operate at maximum pressure. The partially-closed enter s ommonly se d s ilot spool to actuate a primary spool. The inlet is closed but the system ports are open to the reservoir. In the semi- open configuration, he cylinder ports are open to the high-pressure ort. his ype ermits elief of igh pressure at he cylinder ports aused y emporary overload force on he actuator.

Many of the position-valve designs incorporate other functions n ddition o low-direction ontrol. ne

such xample s he deceleration alve llustrated n Fig. 2-59. The flow can be shut off at a rate determined by he aper of the pool. everal deceleration alve designs are available, nd some are provided with ad - justable spool apers.

Fig. 2-59. Mechanically Operated, Nonadjustable Deceleration Valve

[From: luid Power ssue; Machine Design. Used by permission of Penton ublishing Co.]

Shuttle valvesare used when control is required frommore han ne ource. ig . -6 0 hows hree-port shuttle valve which provides a liquid path for tw o alternate sources. A s long as pressure in the right inlet port is greater than in the left, the shuttle piston closes the left ort. hen ressure t he eft ort ecomes greater than at the right, the piston moves to the right against top, losing he ight ort nd pening the eft.

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(3 ) ositive-displacement metering valves: An intermittent low of a specific volume of liquid can be obtained by using a positive-displacement metering valve. The valve consists of a free-floating piston whose stroke can e hanged y n djustment crew Fig. -65). Such valves can be applied, for example, to control flow to a linear actuator used to obtain accurate, ntermit-

tent motion.

Fig. 2 -65 . Positive-displacement Metering Valve

[From: E. C. Fitch, Fluid Power and Control Systems. Used y permission of McGraw-Hill, nc.]

(4 ) low-divider valves: Flow-divider alves utilize sliding elements to change the orifice area (Fig. -66). They distribute the flowto multiple lines, each of which then ha s the same flow rate downstream of the valve. They re enerally pressure-compensating alves nd are frequently used to synchronize the motion of several inear actuators.

Valve port^

Cylinder ports'

Fig. 2-66. Pressure-compensated Flow-divider


2-8.3 VALVE ACTUATION

In order to respond to the system requirements or to the commands of the operator, hydraulic control valves must beprovided with a means of actuation. Some formof actuation is required, for example, to move the spool in a position valve, to adjust flow-control valves, or to change the setting of a pressure-control valve. The ac - tuation methods normally used are manual, mechanical, lectrical, or luid. Mechanical ctuators nclude springs, ams, nd mechanical inkages. Electric control utilizes solenoids. Fluid actuation requires either a liquid or gas pilot luid.

2-8.3.1 Manual Actuation

Manual ctuation equires ction y n perator who must make a control judgment based upon some system requirement. Manual valve response is limited by he ction of the operator; ence, low eactions, such as forces generated in the system, are more critical

than n ilot- or lectrically-actuated alves. Manual control s requently se d when esponse im e s ot critical and when some system change must be initiated by the operator. It is widely used in machine tools and mobile equipment.

2-8.3.2 Spring Actuation

From he discussion of valves n his hapter, t s evident that springs are widely used to provide force for a variety of valve operations. owever, hey eldom supply he ntire orce equired; hey re sually s-

sisted y orce rom nother source which ctually determines the manner in which the valve mechanism will react. Often the primary valveactuator acts against a spring which ends to old he alve n he eu- tral osition.

2-8.3.3 Cam Actuation

In am-actuated alve, he operating inkage s actuated y am hich s mounted n oving machine element. The deceleration valve illustrated in Fig. -5 9 s equipped o be operated by a cam.

2-8.3.4 Solenoid Actuation

Solenoid-operated valves are generally small, single- stage evices. They an , owever, e se d o ontrol large, pilot-operated valves as part of a two-stage system. n uch ystems, urrent equirements re ow , thus reducing the size of the solenoids. Most applications se 15 V, 0 ps olenoids; owever, hey re available in wide ange of AC or DC oltages. DC solenoids are quiet in operation, whereas AC solenoids may hum or chatter. The olenoids re nergized y signals from pressure switches, limit switches, or timers which sually operate through power or signal elays to ccommodate he urrent equired o ctuate he solenoid.

Solenoid actuation affords considerable flexibility in hydraulic system design. System commands can be obtained from signals in an y part of the circuit. For exam pie,

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- Sliding leeve

: Pilot ressure

r-ir—1J—irn

— Fulcrum □ n U D D-

(usually adjustable)

Second tage

Mechanical - Positional Hydraulic-Follower

Pilot ressure

-Second tage

Mechanical-Force alance

Amplifier Electrical ignal related o position ^LVDT

Nonsliding sleeve

Hydraulic-Load Pressure

Pilot pressure -

V - /LVDT

Nonsliding

\ £

im __ _, _

Linear-Variable Differential ransformer Proportional Position n o feedback)

Fig. 2-69. Servovalve nternal Feedback Sys tems


of a hydraulic system. Prediction of valve performance requires curves of pressure vs low nd valuation of several valve coefficients. Pressure-flow curves can be

generated rom xperimental data, nd alve oefficients can be derived from these curves. However, n analytical pproach o determine valve oefficients s possible. The difficulty of the analysis depends on the complexity of the alve. n ddition o ressure-flow curves and valve coefficients, alve analysis can ield general flow equations, leakage flow information, and expressions for the forces that occur in alves.

A omplete nalytical method or he nalysis of valves is presented in the text by Merrit (Ref. ). The method given by Merrit (Ref. 4) is for four-way spool valves with examples of the applications of the method to other types of valves.

A complete analysis of a valve will yield the following information:

(1 ) eneral Flow Relationships:General flow equations express the flow of hydraulic fluid at the load or at the pump as a function of the hydraulic system and valve parameters.

(2 ) alve Coefficients: Valve coefficients are an ex - pression of the sensitivity of the flow of hydraulic fluid at he oa d o hanges n he alve opening or he

liquid pressure. (3 ) eakage lows: n ractice, ll alves av e

clearances between moving parts and these clearances result in leaks. Leakage flow equations relate the magnitude of the leakage to valve and system parameters.

(4 ) troking Forces: Stroking orces re the forces that oppose the motion of the valvespool or stem. They affect the ease of operation of a valve.

(5 ) lo w Forces: Flow forces are forces on , or in, the valve du e to hydraulic eactions.

2-8.5 VALVE DESIGN CONSIDERATIONS

The first consideration in valve design fo r a specific application s the type of valve to be used. The three major types-sliding, seating, and flow-dividing valvesare illustrated by the spool valve (Fig. 2-43), the flapper valve Fig. -44), nd he jet-pipe alve Fig. -46),

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affects null flow gain and adds system stability. Maxi- mizing alve troke s lso esirable ecause ith longer strokes, here is more resolution near null nd improved performance with dirty luids. With on g stroke, ports remain open longer and dirt particles are flushed from he orifice.

A s iquid lows hrough low ontrol alve, he change n potential nergy s dissipated s eat. This increase in hermal energy QAs given s (Ref. ):

Q£= ASG GAP, Btu/hr (2-4)

2-9 HEAT EXCHANGERS

Heat is generated in all hydraulic systems. The inherent echanical nd hermodynamic nefficiencies f pumps and motors result in heat generation. Much of this heat is transferred to the hydraulic fluid, ausing a ise n luid emperature. ince ll hydraulic luids exhibit imited emperature ange ver hich he viscosity and ubricating characteristics are optimum, the heat must be dissipated to assure satisfactory opera-

tion. Some heat is removed by dissipation to the environment. f this heat transfer is not sufficient to maintain he esired luid emperature, t hen ecomes necessary to provide heat exchangers to supplement the natural dissipation.

The nalysis of temperature-control problems n hydraulic system egins with n stimate of the total heat ejection rom he ystem. This an e done n several ways. The heat ejection can be treated as he input power less the actual mechanical work, based on a convenient time interval.' It ca n also be estimated on the basis of pump output*. The increase in thermal en - ergy ue o pump operation an e stimated y he

relation Ref. )

Q P -486GP(1 A, Btu/hr (2-2)

where

Qp = ncrease in hermal energy due to pump, Btu/hr

G = low rate, pm P = perating pressure, si V = ecimal operating efficiency

If the pump contributes to no external work, the power input oes ntirely nto ncreased hermal nergy Qp. Then (Ref. ):

CP

öp= 1.486 —, Btu/hr

where A Pis the pressure drop in ps i across the valve. A imilar xpression olds or he heat dissipated s liquid flows through a transfer line. The pressure drop is hen he pressure drop hrough he ine. With his simplified approach, the total thermal energy absorbed by the fluid is the sum of the pump contribution nd that of al l pressure drops. The heat can be dissipated from he urfaces f the ircuit omponents nd, f necessary, emoved by a heat xchanger.

2-9.1 MODES OF HEAT TRANSFER

Heat can be removed from the system by all three of the basic modes of heat ransfer-conduction, onvection, nd adiation.

2-9.1.1 Conduction

Thermal conduction is the transfer of heat through a gas, liquid, or solid by means of collisions or intimate contact etween he molecules. he mount of heat transferred y onduction s iven y Fourier's Law. For simple one-dimensional low this aw educes to

Q = kA (j), Btu/hr

2-5)

where

(2-3)

Q = ate of heat flow, Btu/hr k = hermal conductivity of

material, Btu/(hr)(ft 2)(°F/ft) A = rea normal o direction of

flow, t2

AT = emperature difference between warmer and cooler surfaces of the material, F

j? = hickness of material, t More

general forms of the conduction equation must be used f the heat flow is other than one-dimensional.

2-9.1.2 Convection

Heat transfer by convection requires gross motion of liquid particles involving the transport of regions of the

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liquid at different temperatures. ree, or natural, convection occurs when the liquid particles move because of density gradients established by temperature gradients. f the liquid is circulated by external means, he process s alled orced onvection. onvection heat transfer rate Q is governed by a relation developed by Newton Ref. ):

Q = hAAT, Btu/hr

where Q — ate of heat flow, Btu/hr h = onvective film oefficient,

Btu/(hr)(ft 2)(°F) A = rea of surface exposed o he

fluid nd normal to heat flow direction, t

AT = emperature difference between the fluid nd he surface, F

2-9.1.4 Overall Heat Transfer Coefficient

The ontributions f onduction, onvection, nd radiation to net heat transfer can be combined by making use of the concept ofthe overall heat transfer coefficient which s defined by he relation

Q = UAAT, total (2-8)

(2-6) where Q U :

rate of heat low, Btu/hr overall heat ransfer coefficient, Btu/(hr)(ft 2)(T) 2

A = eat ransfer area, t A Ttota i otal emperature difference

across which he heat s being transferred, F

The overall coefficient is a measure of the thermal con- ductance of the system,

This elation ctually efines he ilm oefficient . Only in the most ideal situations can the film coefficient be computed. Empirical relations are often employed to estimate a value of h .

2-9.1.3 Radiation

Thermal radiation involves the transport of thermal energy y eans f lectromagnetic adiation. he amount of heat transferred by radiation depends on the relative onfiguration f he reas hich xchange heat, heir emperatures, nd he nature of their urfaces. The governing elation s

Q = FAa(Tt-T ), Btu/hr (2-7)

where

Q = ate of heat low, Btu/hr F = dimensionless factor which

accounts for the geometric orientation of the surfaces nd their emittances

A = rea of radiating surface, t < r = tefan-Boltzmann constant

0.1714 x 0"8 Btu/(hr) ft2) a? )

T2 = emperature of radiating surface, R

Ty = emperature of sink or receiving surface, R

UA = 1 i?, +i? 2 + ... + Rn (2-9)

where 7?,is the thermal resistance of system component i and as units of hr-°F/Btu.

Consider, or xample, he ase of ounterflow plane wall heat exchanger as shown in Fig. 2-71. Under steady-state conditions the amount of heat transfer be - tween he wo fluids is given y

Q = hi 2 A(T,-T 2)= v A(T2- T 3)

f t 23 = h^A(T 3 TA)

This can be expressed as three simultaneous equations

fo r the temperature differences and solved for the total temperature difference:

A T-'- T T'-UL*t+L) 2-10)

or

Q A AT total

\lh 12 lkw + 1/A J3' A HI 34

Then rom Eq. -8

U 1 / Ä12 +^23/*W + 1 / 34

(2-11)

(2-12)

Additional factors such as dirt and scale deposits can contribute to the thermal resistance in heat exchangers. In such cases, appropriate terms are added to the system esistances n Eq. -9 .

2-9.2 TYPES OF COOLING SYSTEMS In eneral, heat transfer in hydraulic system will

involve om e combination of the three modes of heat

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Fig. 2 - 7 1 . Counterf low Plane Wa l l Heat Exchanger

transfer. If it is found that the heat dissipated from the surfaces of the system is insufficient to maintain a satisfactory fluid temperature, then a heat exchanger is re - quired. Most heat exchangers for hydraulic fluids are either air-cooled or water-cooled.

2-9.2.1 Air-cooled Heat Exchangers

Air is often se d as the coolant in heat exchangers for mobile hydraulic systems, or in stationary systems which generate moderate amounts of heat. A blower or fan s sually se d o irculate he ir cross inned tubes hrough which he hydraulic luid lows Fig. 2-72). ir-cooled nits re imited o pplications where the desired hydraulic fluid outlet temperature is at east 0°F above the dry bulb air temperature.

2-9.2.2 Water-cooled Heat Exchangers

The use of water as a coolant is common practice in stationary ystems. The ilm oefficient n he water side is generally the same order of magnitude as on the hydraulic-fluid ide. Therefore, water-cooled eat x- changers re sually hell-and-tube ype here he heat-transfer area on the cold side is approximately the same as on he hot ide. uch an exchanger is shown in Fig. 2-73. It consists of a tube bundle within a shell. The tubes are baffled (not shown) so that the coolant flow in the shell is perpendicular to the tube axis. Most shell-and-tube heat xchangers used in hydraulic systems are either single- or double-pass units. In a single- pass unit, he wo iquids enerally low n opposite directions. n double-pass exchanger, he hydraulic fluid generally enters the same end at which the water enters and eaves.

RELIEF OR HIGH VOL UM E P U M P RELIEF OR O W VOL UM E P U M P

REDUCING VALVE

SUC TION

STRAINER "SUCTION

STRAINER

TO 4 W AY , ALVE a

\ WIPECYL.

FINNED CONDUCTORS

Fig. 2-72. Hydraulic Circuit With Air-cooled H eat Exchangers

[From: Pippenger and Hicks, ndustrial Hydraulics. Used by permission of cGraw-Hill, nc.]

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TABLE 2-1.

LOSS COEFFICIENTS O F H Y D R A U LI C SY ST E M S1

Flow Line Element Loss Coefficient, K

Globe valve, wide open 10.0 Angle valve, wide open 5.0

Gate valve, wide open 0.19 1 /4 closed 1.15 1/2 closed 5.6 3/4 closed 24.0

Standard T 1.8 Standard elbow 0.9 Medium-sweep elbow 0.75 Long-sweep elbow 0.60 45-degree elbow 0.42 Close return bend 2 .2 Borda entrance 0.83 Sudden enlargement :f

To reservoir or to large cylinder 1.0

d/D= /4 0.92 d/D = 1/2 0.56 d/D =3/4 0.19

Sudden contraction:From reservoir or from large cylinder 0.5 d/D = 1 /4 0.42 d/D =1/2 0.33 d/D =31A 0.19

f D = large diameter d small diameter

G = low ate, pm s = pecific gravity of liquid /= riction actor

The Crane Company has published a reference which discusses pressure loss calculations and presents valuable elated data (Ref. ).

2-10.1.2 Pressure Surges

The peak pressures in a hydraulic line occur when a hydraulic hock s generated y udden hange n flow onditions uch s he apid losing of a alve. These pressure surges propagate through the distribution ystem t he local peed of sound. They re e- flected from various internal surfaces until the kinetic energy of the- original hock s dissipated by riction. Pressure surges are usually accompanied by vibration

and oise. he hydraulic ines nd onnectors must have sufficient trength to contain and suppress these shock-induced pressure surges. This capability may be a function of both ipe strength nd ine layout.

2-10.1.3 Pipe an d Tubing Sizes

Standard dimensions of pipe and tubing are given in Tables 2-2 and 2-3, espectively.

2-10.2 HOSE, TUBING, A N D IP E FITTINGS

Pipe nd ubing ittings an e ither hreaded or permanent. Permanent methods include various forms of brazing, welding, waging, nd dhesive bonding.Such ssembly methods re applied where low nitial cost, eliability, nd weight re important actors.

Threaded ipe-fitting echniques nclude apered pipe threads, langes, A E O-ring ports, and straight- thread ports with metal eals. onthreaded ube ittings ca n be of three types-flare, self-flare, or flareless. Flare fittings are illustrated in Fig. 2-74. Typical flareless ittings re hown n ig . -75. elf-flare ittings incorporate a wedge-shaped sleeve which enlarges the tube ending when he nut s tightened.

Hose fittings are either permanent or reusable. High- pressure permanent ittings re actory-assembled n the hose. Reusable fittings are available with pressure ratings up to 5,000 psi. Self-sealing couplings are sometimes used with hose in hydraulic piping systems. The four basic self-sealing types-double poppet, sleeve and poppet, lide-seal, nd ouble otating ball-are llustrated in ig . -76.

2-11 SHOCK ABSORBERS

Fluid power is often sed o cushion or absorb the impact caused when a moving mass must be stopped. If the energy of the moving mass is to be dissipated, a shock bsorber is sed. The working fluid n shock absorber can be a liquid, a gas, or a combination of the two. Shock absorbers are available in a variety of different esigns and configurations.

Most shock absorbers, called nonregenerative shock absorbers, issipate ll of the nergy of the moving mass. hey ely n prings or other mechanisms o return he shock absorber to n quilibrium osition. Common automobile shock absorbers are an example. However, there is an important class of shock absorbers, alled ydropneumatic echanisms, hat se pneumatic power o eturn the shock bsorber o

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CHAPTER

FLUID PROPERTIES, SIGNIFICANCE, A N D TEST METHODS

3-0 IST OF SYMBOLS

A A = rea, n. or cm B0 = sothermal secant bulk modulus

at psig nd emperature , psi Bs = diabatic (isentropic) secant

bulk modulus, si Bs = diabatic (isentropic) tangent

bulk modulus, si Bso = onic bulk modulus, si

Bt = sothermal ecant bulk modulus at pressure p and temperature t, ps i

Bt = sothermal angent bulk modulus at pressure p and temperature , psi

C = peed of sound, cm/sec Cs = sentropic compressibility C t = sothermal compressibility C p = pecific heat t constant

pressure, al/g-°C c v = pecific heat t onstant

volume, al/g-°C D = iameter, n. d = ength, m or in. e = .71828, he base of natural

logarithms E° = iscosity, Engler degrees F = orce, b or dyneH = iscosity t 00°F of a standard

fluid of 100 Viscosity ndex having the same viscosity at 210T as the fluid whose Viscosity ndex s o be calculated

k = onstant for a given oil and temperature, psi)"1

L = iscosity t 00°F of a standard fluid of 0 Viscosity ndex having the same iscosity t 210°F as he fluid whose

3-1

Viscosity ndex is to be calculated

N = elative surface speed p = ressure, si, sia, or psig R = ate of shear, ec"1

Rn = eynolds number, dimensionless

s = pecific gravity 5 = hearing stress, si or dyne/cm 2

t = emperature T= ime, ec U = iscosity at 00°F of the fluid

whose Viscosity ndex s to be calculated

V = elocity, m/sec or ft/sec V0 = nitial olume

V.l. = iscosity ndex, dimensionless VTC = iscosity emperature coefficient

Z = luid iscosity ß = onversion factor P = atio of bulk moduli or specific

heats, imensionless rj = bsolute iscosity, oise or

centipoise (cp), dyne-sec/cm 2

V = inematic iscosity, toke or centistoke (cSt), m2 /sec

p = luid ensity, g/cm 3

p ensity at atmospheric temperature and pressure, g/cm 3

GENERAL

The pecific equirements of a hydraulic luid re determined by the design of the hydraulic system and by the functions the system must perform. A liquid that is satisfactory as a hydraulic fluid in on e application or system may be completely unsuitable in second p- plication or system. Therefore, in considering the properties required of a hydraulic fluid, it should be remem- bered that the relative importance of an y one property

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will depend upon he hydraulic ystem, its use, and its nvironment.

The various properties which re mportant n he selection nd se of hydraulic luids re presented n this chapter. om e properties may be important n all liquids, while others have significance only n imited applications. roperties re iscussed n elation o

their function in a hydraulic system. The importance of these properties is assessed, and methods for measuring them re given.

3-2 PHYSICAL PROPERTIES

3-2.1 VISCOSITY

Viscosity is on e of the most important properties of a liquid from the standpoint of its performance in hy -

draulic systems. t is the resistance offered by a liquid to relative motion of its molecules or the esistance a liquid offers to low. Temperature s he most mportant ariable affecting viscosity and must be stated n all iscosity data.

Viscosity s efined y ewton's aw-at iven point in a liquid, the shearing stress Sis directly proportional o he ate of shear R, .e.,

S=VR (3-1)

The proportionality constant 7 is known as the coefficient of viscosity or simply the viscosity. ince for the

relative otion f wo arallel ayers f iquid he shearing stress is equal to F/A, where Fis the force and A is the area, and since the rate of shear is equal to V/d where \ % he elocity and d is the distance between the layers (see Fig. -1), Eq. -1 may be written s

or

F A

V

4 i) Fd AV

(3-2)

(3-3)

3-2.1.1 Absolute Viscosity

The viscosity J defined by Eq. -3 is the absolute or

STATIONARY PLATE

Fig. 3-1. elocity Distribution n Liquid Between Two Parallel Plates With th e Top Plate Moving With Respec t to he Stationary Bottom Plate

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dynamic viscosity. If the metric system of units (centimeter, ram, econd) is used, he unit of absolute viscosity is the dyne-second per square centimeter or the poise. Because the poise is a rather large unit, the centipoise (one hundredth of a poise) is customarily used. Pure water at a temperature of 20.2°C (68.4°F) has an absolute viscosity of on e centipoise. f the English sys-

tem of units (foot, pound, second) is used, he unit of absolute viscosity is the pound-second per square inch or the reyn. ince the reyn is an extremely large unit, the newton (one millionth of a reyn) is more convenient. onversion between metric nd English ystem units of absolute viscosity can be made on the basis that one eyn or on e million newtons) s equal o 8,950 poises (or ,895,000 centipoises).

3-2.1.2 Kinematic Viscosity

The ratio of the absolute viscosity of a liquid to its density frequently occurs in the study of viscosity and hydraulics and the term "kinematic viscosity" with the symbol has been assigned to it

P (3-4)

where is the density. n he metric system, he unit of kinematic viscosity is the square centimeter per second or the stoke. The centistoke (one hundredth of a stoke) is more generally used. The kinematic viscosity of a liquid can be looked upon as the liquid's resistance to flow under its wn gravity head.

The aybolt Universal nd aybolt Furol iscosity scales, se d extensively in he United States, ive viscosity in terms of seconds-Saybolt Universal econds (SUS) or aybolt Furol econds SFS). A Furol iscosity is approximately one-tenth of the Universal viscosity for the same liquid at the same temperature. The Furol scale is used chiefly fo r petroleum products hav-

ing viscosities greater than ,000 SUS, uc h s heavy fuel nd oad ils.

3-2.1.4 Viscosity Unit Convers ions

A viscosity determined in a particular instrument at a specific temperature ca n be converted to the equivalent iscosity n om e other nstrument t he am e temperature. ide ariety f quations, ables, charts, and nomographs have been developed to facilitate such onversions. Currently, he rend s oward expressing viscosity n the metric units of centipoises (cp) and centistokes (cSt). Data in convenient abular form fo r the conversion of kinematic viscosity to Say- bolt Universal and Saybolt Furol viscosity are provided in American ociety or Testing aterials ASTM) Method D-2161-66 (Ref. 2). Procedures fo r converting the ive more ommon iscosity cales o he metric scale in centistokes re described.

(1 ) Saybolt Universal seconds to centistokes:

V .226 T - y 2 T< 00se c (3-5)

(T = fflux time n seconds)

3-2.1.3 Other Viscosity Scales

Numerous other scales of viscosity have been established hich xpress iscosity n erms of arbitrary units based on the instruments used to make the measurement. he ive most ommon cales se d n he petroleum industry are the Saybolt Universal and Say- bolt Furol used mainly in the United States, he Red- wood N o. Standard) nd Redwood No. Admi- ralty) used in Great Britain, and the Engler used chiefly in Germany and other countries in Europe. A ll five are empirical instruments in that the time of outflow of an arbitrary onstant mount of liquid hrough ixed orifice is quoted as measurement of the viscosity of the iquid. he nstruments re imilar, ut various dimensions and amounts of liquid used assign different viscosity numbers to the same fluid; therefore, the viscosity is meaningful only when the instrument and temperature are also named Ref. ).

IMV .220 7 - jF.T > 100 sec (3-6)

(2 ) Saybolt Furol econds to centistokes:

V .2 4 T - y 2 5 < 0 sec (3-7)

V .1 6 7 - y-,T> 40 sec (3-8)

(3 ) Redwood N o. Standard) econds o centi-

stokes: 179

V .260 - yr, 34 < < 1 00 sec (3-9)

50 v .247 - ~, > 100s ec 3-10)

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(4 ) Redwood N o. (Admiralty) seconds to entistokes:

NEWTONIAN.' ID

V .46 - y, 32 < 0 sec (3-11)

V .45 , > 0 sec

3-12)

(5) Engler Degrees (£") to centistokes:

V .0E° - ^-, 1.35 < ° .2 (3-13)

-, „ .0 v .6 E° - — £ > .2

3-14)

Rate of Shear ate f Shear Fig. 3-2 . Viscosity nd hear tress urves or a

Newtonian Fluid

3-2.1.5 Newtonian luids

When a liquid flows in such a manner that the shearing stress S is directly proportional to the rate of shear (see par. 3-2.1), the liquid is said to flow in accordance with Newton's Law nd s alled Newtonian luid. Flow of this type is know as "viscous" or "streamline" flow. iscous low onsists of an orderly motion n which layers of liquid slide past on e another in a direction parallel to the direction of flow. The viscosity 7 is constant with espect o the ate of shear R (see ig. 3-2). Most hydraulic fluids behave in a Newtonian, or nearly Newtonian, manner at he emperatures, ressures, and flow rates normally encountered in hydraulic systems. However, there are some types of materials that are never Newtonian, and most Newtonian fluids can be made to behave in a non-Newtonian manner by changing the pressure, emperature, and/or flow ate sufficiently (Ref. 3). Non-Newtonian materials are discussed n he paragraphs which ollow.

3-2.1.6 Non-Newtonian Materials

The iscosities f om e aterials re ltered y shearing effects and these materials are termed non- Newtonian". The viscosity depends on the rate of shear at which it s measured. ince c non-Newtonian luid can av e n unlimited number of viscosities as he shear ate is varied), he term apparent viscosity" s used nstead f iscosity. pparent iscosity s x- pressed n units of absolute iscosity, nd he ate of shear used n he measurement s iven.

3- 4

Non-Newtonian aterials ay e lassified nto five types-plastic, pseudoplastic, ilatant, thixotropic,

an d rheopectic. (1 ) lastic. A definite minimum stress or force must be pplied o his yp e of material efore ny low occurs, nd viscosity decreases as shear rate increases (see ig . -3). Examples of such materials re putty, molding clay, nd many ypes of greases.

PLASTIC

> >

r-i C O

o o

e n

Rate of Shear Shear Stress

Fig. 3-3 . Viscosity nd hear tress urves or a Plastic Mater ia l

(2 ) seudoplastic. This type of material has no fixed yield point; however, he viscosity does decrease with

increasing shear rates (see Fig. -4). Examples of such materials are water base liquids and resinous materials.

(3 ) ilatant. The apparent viscosity of this type of material increases as the rate of shear increases, and the material will often solidify t igh ates of shear (see

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A M C P 706-123

A eparate etermination f he density ust e made before calculating the absolute viscosity. ASTM D-445-65 (Ref. 5) lists several approved test procedures for determining density.

The Cannon-Fenske apillary viscometer see ig. 3-10) is the most common on e used in hydraulic fluid work. A cross section of the Saybolt viscometer, widely

used in the petroleum industry, is shown in Fig. -11.

250. Ü

(dimensions n illimeters) Fig. -1 0 Cannon-Fenske Capil lary Tube Viscometer

OVERFLOW RIM

4.92

(dimensions in inches) ORK

STOPPER Fig. - 11 . Cross-sectional View of a Saybolt Viscom-

eter

3-2.1.10 Significance of Viscosity

The ingle most mportant property of a hydraulic fluid is its viscosity. Various components within a hy - draulic system have competing requirements as to high or low viscosity. High viscosity provides thick lubricating ilms nd educes internal eakage. ow iscosity results in ess internal friction, maller pressure losses in ipes and alves, nd an ncrease in ontrol ction and omponent esponse. Thus, compromise in iscosity requirements must be made. The viscosity of the hydraulic fluid affects the response of system components, and because its sensitivity to temperature usually imposes imitations n he upper or ower operating temperature of an y hydraulic ystem, iscosity must always be considered n design calculations.

3-2.1.11 Test Methods fo r Viscosity

(1 ) inematic iscosity Test Methods : Federal Test Method 05.4 (Ref. )

ASTM D-445-65 Ref. ) These methods describe the procedure for determin-

ing he kinematic iscosity of transparent or opaque fluids higher than 0.2 centistoke. Determinations may be made t emperatures where he low n he lass capillary ype iscometers s Newtonian. The im e s measured or ixed volume of est luid o low through he apillary under ravity head nd t closely controlled temperature. The kinematic viscosity is then calculated from the efflux time and the viscometer calibration actor.

Precision : For lean ransparent ils ested t 00° and 10°F, esults hould ot e onsidered uspect unless they differ by more than the following amounts:

Repeatability-0.35 percent of mean Reproducibi ity-0.7 percent of mean (2 ) aybolt Viscosity Test Methods : Federal Test Method 04.8 Ref. )

ASTM D-88-56 (Ref. ) These methods describe the procedure for determin-

ing the Saybolt viscosity of petroleum products in the temperature range of 70° to 10°F. The efflux im e in seconds of 60 ml of the sample flowing under gravity head hrough alibrated rifice s measured under carefully controlled temperature conditions. A Univer- sal orifice is used fo r Saybolt Universal viscosity and a Furol rifice s sed or aybolt Furol iscosity. The time is corrected by an orifice factor and reported as the viscosity of the sample at the test temperature in Say- bolt Universal Seconds (SUS) or Saybolt Furol Seconds (SFS). Viscosity values below 00 sec are reported o

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A M C P 706-123

TABLE -1. VISCOSITY REQUIREMENTS O F IV E PECIFICATION HYDRAULIC LUIDS*

Temperature, °F

MIL-H-5606B MIL-H-8446B MIL-H-13866B (MR) W-B-680a MIL-H-27601A

-65 3000 (max) 2500 (max) To be reported -40 500 (max) 1800(max) 4000 (max) -30 4200(max)

100 To be reported 55 (min) 3.5 (min) at 122°F 385 (max) at0°F 1 30 10.0 (min) 210 To be reported 15 (min) 1.3 (min)

at 212°F 3.2 (min)

400 2 .5 (min) Report at 500°F

n centistokes. AU viscosities References: MIL-H-5606B; Hydraulic Fluid, Petroleum Base, Aircraft, Missile, an d Ordnance.

MIL-H-8446B; Hydraulic Fluids, Nonpetroleum Base, Aircraft. MIL-H-13866B; Hydraulic Fluid, Petroleum Base, Artillery Recoil, Special W-V-680a; B rake Fluid, Automotive. MlL-H-2760\ A; Hydraulic Fluid, Petroleum, High Temperature, Flight Vehicle.

3-2.2.1 ASTM iscosity-temperature Charts

Many ystems ave een eveloped or xpressing the iscosity-temperature haracteristics f iquids. The most widely used procedure utilizes the viscosity- temperature charts published by ASTM (see Fig. 3-13). These charts, available from ASTM, are described in an ASTM Method (Ref. 3) and in a Federal Test Method (Ref. 4). iv e different viscosity-temperature harts similar o hat hown n ig . -1 3 re vailable with various emperature anges nd ither kinematic r Saybolt niversal iscosity cales. hese harts re constructed so that the plot of viscosity vs temperature is a straight line for most petroleum liquids. Thus, only two iscosity easurements, sually t 00° nd 210°F, need to be made to determine a line from which the approximate viscosity at an y other temperature can be ead.

The viscosity-temperature charts are useful for predicting iscosity nly when he graph or iquid s linear. n most instances this will occur over the temperature range that a given liquid is Newtonian. How- ever, many Newtonian petroleum iquids will deviate from linearity at low viscosities, i.e., high temperature. Many iquids eviate rom inearity near heir loud points par. -2.6.2) ecause of the ormation of wax particles. or non-Newtonian iquids, nd or New- tonian liquids that are in nonlinear conditions of behavior, the plot of viscosity vs temperature cannot be used

to predict iscosity. The ctual viscosity-temperature properties of the liquid must be determined and plotted.

The ASTM charts are based on a modified Walther equation:

log [log(i> + c)] = A og°R B

3-17)

where c = constant

R = emperature, Rankine

V = iscosity, St A,B = onstants for each luid The ASTM hart xpresses as onstant arying from 0.75 t 0.4 cS t to 0.6 at .5 cS t and above (Ref. 15). The use of this equation in chart form obviates the necessity of determining the constants A and B when two or more viscosities are determined experimentally and plotted.

3-2.2.2 ASTM Slope

A simple method of expressing a change in viscosity with temperature is by using the slope of the curve on the ASTM charts. ince the curve accurately portrays the viscosity-temperature characteristics of a particular liquid, ts slope is a measure of the liquid's sensitivity to hange n emperature. The lope may e determined graphically from the chart as the tangent of the angle formed by the viscosity-temperature line and the

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AMCP 706-123

K I N E M AT I C ISCOSITY, S t

O c 9° 8 8 0 0

£ c 0 s c w; eS 0 0 c c c c c

s

s 0y

s 2

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2 Stt.Sn/

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AMCP 706-1 23

lines of constant iscosity see ig . -14). he lope values are unitless and negative, but by convention the minus sign is omitted. The greater the slope, the greater the change in viscosity for a given change in temperature. If the slope is determined at a temperature where the graph is not a straight line, the slope of the tangent to he curve at he temperature in question s sed.

The ASTM lope s asily determined nd alues accurate to within 0.01 lope units can be obtained by se of the chart nd imple uler. However, he slope as ittle hysical eaning nd as ot een adopted for general se .

Subsequently, however, solvent refining, the use of ad - ditives, and synthetics have produced materials that are outside the .l . cale in both directions.

The .l . of a liquid with a given iscosity t 210T is alculated y elating ts iscosity t 00°F o he viscosity t 00T or ach of the tandard ractions having iscosity t 10°F qual o hat of the n-

known at 210°F. he .l . s calculated by the ollowing quation:

V.l. « 1 00 (3-19)

3-2.2.3 Viscosity-temperature Coefficient

Another way of expressing the viscosity-temperature relationship of a liquid is the viscosity-temperature coefficient VTC) which s defined by

V TC '100 "210

'100

^210

^100 (3-18)

where y100 nd >2io are the kinematic viscosities in centistokes of the iquid t 00° nd 10°F, espectively. The VTC ha s the advantage of expressing the viscosity- temperature characteristics of a liquid as a number, but by efinition, s pplicable nly o he emperature range of 100° to 210°F. It has not found wide use in the hydraulic luid ndustry.

3-2.2.4 Viscosity index

The Viscosity ndex V.l.) of a iquid s number indicating he ffect f hange n emperature n viscosity. A low .l. signifies a relatively large change of viscosity with emperature. A igh .l . ignifies relatively mall hange of viscosity with emperature. The convenience afforded by the use of a single number to xpress he viscosity-temperature characteristics of a liquid has resulted in the widespread adoption of the viscosity ndex system n he petroleum ndustry.

The .l. s n mpirical cale sing wo eries of petroleum ractions as standards. One fraction which seemed o have minimum viscosity-temperature en- sitivity was arbitrarily assigned a .l. of 100. The other fraction ith aximum iscosity-temperature en- sitivity was ssigned .l. of zero. At he ime he index cale was eveloped, ll other petroleum ractions were expected to fall within the zero to 100 limits.

where L = iscosity t 00°F of a

petroleum fraction.of 0 .l . having he same viscosity t 210°F as the fluid whose .l . s to be calculated

H= iscosity t 00°F of a petroleum raction of 100 .l . having the same iscosity at 210°F as the fluid whose .l. s to be calculated

U = iscosity at 00T of the fluid whose .l. s to be calculated

An STM ethod Ref. 6) nd ederal est Method (Ref. 7) provide tables of values for L, H, and (L-H) for determining the .l. of a liquid from either the entistoke or he aybolt iscosities t 00° nd 210°F. A schematic representation of .l. s shown in

Fig. -15. The .l. scale as described ha s been in general use in

the United States although it had a number of deficien- cies. For many ears he procedure se d o alculate the .l. was given by ASTM D-567-53 (Ref. 8) which ha s since been replaced because of the anomalies that resulted from use of the method. Some of the problems experienced were

(1 ) t was based on arbitrary standards. (2 ) he ystem broke own or ight ils having

viscosities below about St t 10°F. (3 ) n the range above .l. of 125, the scale became

meaningless since tw o oils that have equal viscosity at 100T but widely different viscosities at 210°F may have the same .l.

(4 ) .l. is no t an additive property. The .l. of an oil blend cannot be determined by manipulation of the V.l. of the ndividual omponents, particularly when widely different ypes of liquids re involved.

3-11

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AMCP 706-123

KINEMATIC VISCOSITY, St

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3-12

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AMCP 706-123

c L — Lt_ _ o i o

_1 ~ —1 z < c « < _ > — • •7 oo Z .pD U

• — i 1—1

~ >

H 100

U H £ C O O U C O i—i

1 „ >

700 . i.

100°F 210°F

Fig. 3 -1 5 . Schematic Representation of Viscosity ndex V.l.)

[From: ubrication, Vol. 7 (1961). Used by permission of Texaco, nc.]

In pite of its hortcomings, he .l . emains he most popular system fo r expressing viscosity-temperature haracteristics f luids. umerous uggestions have been proposed o liminate he hortcomings of the ystem or o ind more undamental means of expressing viscosity-temperature characteristics. Most of the suggested systems were too complex for general use or had faults of their own, so a method (Refs. 6,

17) was eveloped o orrect he eficiencies n he ASTM /.'s bove 00 without hifting he alues between nd 00. Values bove 00 re designated Viscosity ndex Extended V.I.E) Ref. 9) o distinguish hem rom alues btained y he previ- ous method.

3-2.2.5 Test Methods fo r Viscosity-temperature Properties

(1 ) Viscosity-temperature Charts

Test Methods : ASTM D-341-43 Ref. 3) FederalTestMethod9121.1(Ref. 4)

t> hese methods provide pecifications or tandard viscosity-temperature harts e.g., ig . -13) or e- troleum fluids for both kinematic and Saybolt viscosities and fo r a range of temperatures. Charts available from ASTM Headquarters are:

(a) hart A. aybolt Universal Viscosity:-30° to + 450°F, 3 to 00,000,000 Saybolt Universal Seconds

(b) hart . aybolt niversal iscosity, Abridged:-30° to + 350°F, 3 to 00,000 Say- bolt Universal econds

(c) Chart C. inematic Viscosity, igh ange: -30° to 450°F, o 20,000,000 centistokes

(d) hart . inematic iscosity, ow ange: -30° to +450°F, .4 0 to 00 centistokes

(e) hart E. Kinematic Viscosity, L ow Tempera- ture Range:-100° to +450°F, 2.0 to 20,000,000 centistokes

(f) Chart . inematic iscosity, xtended Range:-100° o 700°F, .4 0 o 0,000,000 centistokes

(2 ) Calculation of Viscosity Index Test Methods : Federal Test Method 9111.2 (Ref. 7)

ASTM D-2270-64 (Ref. 6) These methods provide tables and equations for cal-

culating the .l . of petroleum products from their vis-

cosities at 00° and 210°F. Tables are provided for liquids with viscosities at 210°F between the values of 2 1 0 and 5.0 cSt.

Tedious calculation of .l. ca n be eliminated by the use of data in ASTM Data Series 39a, ASTM Viscosity Index Tables Calculated from Kinematic Viscosity, Sep- tember 965. This reference gives .l. in the following

3-13

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AMCP 706-123

ranges: ro m 0 to 200 .l. for all liquids from 2 to 5 cS t at 210°F; up to 300 .l. for liquids from 2.00 to 9.99 cS t at 210T; and up to 250 .l. fo r liquids from 0.00 to 9.98 St t 10°F.

3-2.3 VISCOSITY OF BLENDS OF TW O

LIQUIDS

The ASTM viscosity-temperature charts can be used to predict the composition of a newblend of tw o liquids to give a required viscosity, or to estimate the composition of an existing blend when the viscosities of the two components are known. In this procedure, the vertical scale of any ASTM chart is used without change. The horizontal cale etween °-100°F s elabeled -100 percent and used to represent the percent by volume of the higher viscosity component. The viscosity at a given temperature f he ower iscosity omponent s marked on the zero percent line and the viscosity at the same

temperature of

the

higher

viscosity component

on the 00 percent line. The tw o points are connected by a traight ine, nd he equired volumetric composition of an y blend of intermediate viscosity may be read on the abscissa (see Fig. 3-16). Conversely, the composition of a blend can be estimated when the viscosities of the two components are known and plotted in this manner (Ref. ).

3-2.4 VISCOSITY-PRESSURE PROPERTIES

The viscosity of a liquid varies with pressure as well as temperature. For many years pressure effects in hy - draulic systems were neglected since the pressures encountered were moderate nd he iscosity as not greatly ffected. iscosity ncreases with ncreases n pressure, nd he ate of increase s greater t ower temperatures and pressures. The rate of increase is also influenced by the structural and chemical composition of the fluid. Graphs of viscosity vs pressure at severaltemperatures fo r a typical petroleum fluid are shown in Fig. 3-17. Graphs of viscosity vs temperature at several pressures or a ypical ynthetic fluid re hown n Fig. -18.

Most of the work n viscosity-pressure ffects as been done in studies concerned with lubrication theory. Lubricating fluids fo r ball bearings and gears are often subjected o xtremely igh pressures t ontact urfaces under which their viscosities are increased appreciably. At pressures as low as a few thousand pounds

per quare nch, he ncrease n iscosity an ause considerable ifferences n he esults obtained y lubrication heory calculation Ref. ).

A umber of mpirical quations av e een ug- gested fo r relating viscosity to pressure. The following one, lthough alid nly ver oderate ressure range, s the on e most ommonly se d Ref. 0):

T ? p ? ' p (3-20)

where 7 7 p = bsolute viscosity at pressure p,

cS t V = bsolute viscosity at

atmospheric pressure, St e= .71828 base of natural

logarithms) k = constant fo r a given il nd

temperature, psi)'1

p = ressure, si

Several eneral tatements bout he iscosity-pressure properties of petroleum products an e made, amely:

(1 ) pressure ncrease of about 00 si as he equivalent but opposite effect on viscosity as a temperature increase of 2°F.

(2 ) he am e ncrease n ressure ill how greater effect n iscosity t high ressures han at low ressures.

(3) ower viscosity fluids are less affected by pressure than higher viscosity luids.

(4) n ncrease in pressure will ncrease the .l. The study of the effects of pressure on viscosity is an

area of research that ha s received considerable interest in recent years. The viscosity of liquids at pressures up to 50,000 psi and temperatures up to 425°F ha s been reported by the ASME (Ref. 21) and, more recently, by Wilson (Ref. 2). Klaus et al. Refs. 3-25) have conducted viscosity-pressure studies on numerous liquids, at pressures p o 0,000 si, which re ikely o e encountered in typical hydraulic systems. A s more data are accumulated on viscosity-pressure effects, more in - telligent choices of lubricants and hydraulic fluids will be possible. The inclusion of viscosity-pressure data in design studies could result in the use of liquids of lower viscosity than the classical lubrication equations would indicate. Using a liquid of lower viscosity as the ad - vantage of permitting ower operating emperatures, less liquid friction, nd maller power losses.

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A MC P 706-123

100 90 20,000,0001 tO.000,000 1

5,000,000

2,000,000 I.00Q000 500,000

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VISCOSITY OF BLEND •OF 8% HIGH VISCOSITY COMPONENT A ND 2%

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3-15

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AMCP 706-123

W w i— i O CM I—i

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Fig. 3 - 1 7 . Viscosity vs Pressure at Several Temperatures fo r a Typical Petroleum Fluid

21 [From: ASME Pressure-Viscosity Report, Vol. Used by permission of ASME]

3-2.5 VISCOSITY-SHEAR CHARACTERISTICS

Some ircraft nd many ndustrial hydraulic luids currently n se ontain polymeric hickeners alled Viscosity ndex mprovers, r V.l. mprovers", o reduce viscosity change due to temperature. When liquids containing hese .l. mprovers re ubjected o high rates of shear, they often suffer a loss in viscosity and I. because of degradation of the polymers. The unit of shear ate s he eciprocal econd sec" . A

shear rate of on e reciprocal second occurs when paral- le l planes m apart move in opposite directions at a relative speed of m/sec. High shear rates will occur

where speeds are high and clearances small. Some typica l shear rates are shown in Table 3-2 (Ref. 26). Circu- lation of a hydraulic fluid through a system subjects the fluid to rapid shear rates and sudden pressure changes as it asses through orifices and close tolerance areas (Ref. 27). The resultant loss in viscosity may be either a permanent loss, or a temporary loss, or a combination

of the wo. 3-2.5.1 Temporary Viscosity Loss Du e to

Shear

Temporary iscosity oss s due o rientation r "lining-up" of the long chain polymer molecules in the direction f flow. he polymer molecules hicken

liquid more when they are oriented in a random manner, han when hey re oriented n he direction of flow. The orientation of the molecules can actually be seen when he low n ransparent ubes s bserved under olarized ight Ref. 8). hen he hearing tress s emoved, he iquids egain their rigi-

na l viscosity. Temporary oss of viscosity has wo mportant f-

fects n he erformance f hydraulic luids-an n- crease in leakage and a reduction of fluid friction. Leak- age around close fitting parts increases as the viscosity decreases and can result in reduced system efficiency if the rate becomes to o great. However, the reduction in fluid riction hat ccompanies educed iscosity n- creases ystem fficiency nd erformance. everal methods or easuring he emporary iscosity e- crease have been developed. One method uses a bank of capillary tubes; another uses a rotating tapered plug viscometer. The oncentric ylinder s nother om -

mon apparatus. Any on e of these methods is sufficient for determining the relationship between viscosity and shear ate (Ref. 8).

TA BL E -2 . ESTIMATED S H E A R R AT E S OF L U BRI CA N T S

Applicat ion Radial Clearance Between Moving and Stationary

Parts, in .

Relative Veloci ty of Parts

Shear Rate, sec"1

Piston-cylinder clearance in automotive engine

Plain journal bearing (2-in. diameter)

Ball-type hydraulic pump Bosch piston-type Diesel fuel pump

0.001

0.001 o

0.0001 0.0003 0.00004

200-400 in./sec 1800 rp m

3500 rpm 36 in./sec

200,000 to 400,000 188,000 to

1,820,000 3,000,000 900,000

[From: Klaus an d Fenske, "Some Viscosity shear Characteristics of Lubricants", Lubrication Engineering26 . Used by permission of ASLE.]

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A M C P 706-123

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3-17

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AMCP 706-123

3-2.5.2 Permanent Viscosity Loss Due to Shear

Permanent iscosity oss s he esult f chemical breakdown r echanical upturing f he arge polymer molecules into smaller molecules. Rupture of the polymer molecules may occur in both laminar and

turbulent flow; however, polymer degradation is generally reater nder urbulent onditions. avitation, where large shearing forces are developed by the rapid formation nd ollapse of cavities n he iquid, an cause extensive scission of the polymer chain. Polymer degradation by chemical eactions (oxidation, hydrolysis, radiation, etc.) does occur, but mechanical scission of the polymer chain resulting from the large shearing forces on the molecule is the principal cause of viscosity loss in hydraulic fluids. Viscosity osses due to reduction n he hain ength molecular eight) f he polymer hickener re permanent nd he iquids o not egain heir iscosity he n he shearing orces

are emoved.

3-2.5.3 Test Methods fo r Viscosity-shear Characteristics

There are several methods of measuring permanent shear viscosity oss. Most of them are summarized n ASTM pecial echnical ublication o. 82 Ref. 29). The hree most ommonly se d methods are the pump-orifice test, he sonic method, and the diesel injector method.

(1 ) ump-orifice est: he iquid s ressurized with a pump and the pressure is released by passing the liquid hrough mall rifice to ow pressure rea. After a given number of cycles the amount of permanent hear iscosity oss s xpressed s he percent change in the viscosity at a given temperature. This test simulates ctual ervice onditions nd mploys y- draulic ystem omponents.

Federal Test ethod 471.2 Ref. 0) escribes procedure and apparatus (see Fig. -19) used to determine hear tability of hydraulic luids with pump test. The method consists of pumping one pint of liquid through imulated hydraulic ystem nd eporting changes in visual appearance, viscosity, and neutralization number. Graphs of viscosity loss of MIL-H-5606B fluid during a pump loop test similar to that described above are shown n ig. -20 (Ref. 1).

(2 ) onic Method: The onic ethod onsists f subjecting the liquid to high-frequency vibrations that produce permanent hear breakdown of the polymer

molecules n xtremely hort periods of time s compared to the pump tests. The sonic energy is supplied from magnetostrictive oscillators. O ne such device generates 0 kilocycles per second at 200 watts (Ref. 7). The sonic method as the advantages of using only small sample (5 0 ml or less) of the liquid and requiring on e hour or less to perform. ig. -2 1 Ref. 1) shows

the effect of sonic irradiation on the viscosity of a typical MIL-H-5606B fluid.

The orrelation etween onic esults nd pump est results has been oor in many cases. Recent investiga- tions av e hown hat he poor orrelation might e attributed to at least tw o factors (Ref. 32): (1 ) the sonic procedure s erformed t tmospheric ressure whereas the pump test uses a reservoir under pressure, and (2 ) both methods vary in heir effect on different polymers. The problem of dissolving gases in the liquid from the pressurized reservoir can be reduced by using an nterface uc h s diaphragm etween he iquid and the pressurizing gas. When the effect of dissolved gases and the selective nature of the sonic irradiations are considered, there is closer correlation to data frompump ests. Considerable effort as been xpended n developing a se t of conditions to be used n he sonic method and much of the work ha s been summarized in ASTM Special Technical Publication No.l82(Ref.29).

(3 ) iesel njector ethod: he iesel njector method is similar to the pump-orifice method n hat the iquid s pressurized nd orced hrough mall orifice. In the injector method, the diesel injector serves as both the pressurizing pump and the orifice. Excellent agreement between pump tests an d results obtained by multiple asses hrough he iesel njector av e een obtained (Ref. ).

3-2.6 LOW-TEMPERATURE PROPERTIES

A s hydraulic luids re ooled, hey ecome more viscous and flow becomes slower. f cooling is carried to ufficiently ow emperatures, he luids pproach plastic solids. Many liquids, if cooled under prescribed conditions, ill egin o precipitate wax or eparate components t pecific emperature. This emperature s alled he loud oint. f cooling under re - scribed conditions is continued, a temperature will be

reached t which he il will ot pour or low. This temperature is defined as the solid point. By definition, the pour point s °F above the solid oint. The pour point approximates the lowest temperature at which a liquid will low n ontainer of a iven ize. To e useful, a hydraulic fluid must have a pour point below

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AMCP 706-123

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3-79

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AMCP 706-123

20 0 40 50xl0 4

Pumping Cycles Fig. -20. Effect of Shear U p o n Viscosity of a MIL

H-5606B Hydraul ic Fluid in a P u m p Test" 30

„ 30 h

u 40 cu

O

Mlt -H-5606ß

(SONIC TEST)

J_ I I J_

0 60 120 180 240 300 360

Sonic Exposure ime, in Fig. 3 -21 . Effect of Sonic rradiation on he Viscosity

30 of a MIL-H-5606B Hydraul ic Fluid

the minimum temperatures expected in operation. It is difficult to define either pour point or solid point pre- cisely as the transition from liquid to solid is gradual.

3-2.6.1 Cloud oint

The cloud point is of interest for use at low temperatures. It is defined as the temperature at which wax or other dissolved solids begin to crystallize and become noticeable when liquids are chilled under specified conditions. Dissolved moisture can also cause clouding of a liquid on cooling and lead to erroneous results. Many liquids have no cloud point. Some base stocks have no waxy components and other stocks can have the waxy 3-20

components removed. The latter are referred to as deep dewaxed luids.

3-2.6.2 Pour Point

The pour point may mark emperature t which crystallization of wax has proceeded to such an extent that further lowering of temperature would cause flow to ease waxy pour point) or t may, with wax-free fluids, represent the temperature at which the viscosity is ufficiently high hat urther ooling would ause flow o cease (viscous pour point). Liquids which re free of wax or other components that can precipitate on cooling behave like Newtonian fluids even at low temperatures. The viscosity t he pour point is approximately the same fo r all fluids of this type and has been found to be in the range of 105 to 06 c St.

Most commercially available petroleum fluids have a waxy pour point ather han iscous pour point. They are Newtonian fluids only when the temperature is above the point at which wax begins to separate. The formation of waxy crystals does not mean the fluid has solidified. Flow has been prevented by the crystals but if the liquid is agitated to rupture the crystal.structure, the iquid will low ven hough he emperature s below the pour point. The waxy pour point is dependent upon such factors as the rate of cooling and degree of agitation (Ref. 4). Table 3-3 lists the minimum pour point required by four common Military Specifications fo r hydraulic fluids.

3-2.6.3 Freezing Point

For pure, or essentially pure, hydrocarbons the temperature t which olidification occurs s alled he freezing point. This term is also frequently and loosely used or other petroleum products where the proper term would be either the cloud point, he pour point, or the solid point. The freezing point is defined as the temperature at which a pure hydrocarbon passes from a liquid to a solid state. Test methods for determining freezing points sually pply o uels, olvents, nd other types of relatively pure hydrocarbons.

3-2.6.4 Test Methods fo r Low Temperature

Properties

(1 ) Cloud and Pour Point Test Methods : Federal Test Method 201.8 (Ref. 3)

ASTM D-97-66 (Ref. 4) ASTM D-2500-66 Ref. 5)

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AMCP 706-123

TABLE -3 . POUR POINT R EQ U I R EM EN TS O F F OUR MILITARY SPECIFICATION FLUIDS

Specification Fluid Type U se Pour Point, F, m ax

MIL-H-5606B MIL-H-8446B MIL-H-13866B MIL-H-27601A

Petroleum Nonpetroleum Petroleum Nonpetroleum

Aircraft Aircraft Artillery Aircraft

-75 -75 -50 -65

These methods describe the procedures fo r determining the cloud point for liquids which are transparent in layers 1-1/2 in . n thickness and for determining pour point for an y petroleum fluid.

(a) loud point: (ASTM D-2500-66, Federal Test Method 201.8) A sample of the fluid is placed in est ar, eated t east 5°F bove he approximate loud oint, nd hen hilled n successively ooler baths. At ntervals of 2°F the sample is inspected fo r clouding. When distinct cloudiness or haze appears at the bottom of the test jar, the temperature reading is recorded s he loud oint.

Precision : uplicate esults rom ne aboratory may differ by 4°F and the results of tw o different labs may differ by °F or gas oils. or all other oils, e - suits f uplicate ests hould ot iffer y ore than 0°F.

(b) our point: ASTM -97-66, ederal est Method 201.8) A sample of the fluid is placed

in a test jar of 1-1/4 in. diameter and heated to 15°F bove he xpected pour point, but not hotter than 15°F. The sample is then chilled in uccessively ooler baths. t ntervals of 5°F, he jar s ilted nd he luid urface s inspected or movement. When he luid e- aches a temperature where the jar can be tilted horizontally for 5 se c with no movement, the temperature is recorded as the solid point. The pour oint s aken s he emperature °F above the solid point emperature.

Precision : Results of the pour point from on e laboratory may vary by °F nd rom different aboratories by 0T.

(2 ) Pour Stability Characteristics Test Method : Federal Test Method 03 Ref. 6) This method is used fo r determining the stable pour

point of blends of winter grade motor oil and of certain types of hydraulic fluids.

A sample of the oil is placed in a glass jar in a bath and subjected to a schedule of temperature variations for a period of up to 6 days. The lowest temperature at which no surface movement will occur when the sample is turned horizontally for 3 ec (the solid point) is then determined. The stable pour point is recorded as the temperature 5°F above the solid point. This method differs from he method of par. -2.6.4(1) n hat he sample first undergoes a period of heating and cooling over a period of several days.

Precision : (a) epeatability. Results may vary in on e labora-

tory by 5°F fo r oils with pour stability characteristics. or lends with olid oints below 0°F results may vary 0°F.

(b) eproducibility. Results may vary in different laboratories by 0°F. The averages of three or more esults er aboratory n ifferent laboratories should no t iffer more than °F .

(3) iluted Pour Point Test Method : Federal Test Method 04 (Ref. 7) This method is used for indicating the flow charac-

teristics of engine oils that have been diluted with avia- tion asoline.

A ample of the il s diluted o mixture of 0 percent il nd 0 percent diluent. he diluent s mixture of 80 percent naphtha and 20 percent xylene. The pour point s determined s outlined n ASTM D-97-66 (Ref. 34 ) or Federal Test Method 201.8 (Ref. 33 ) or cloud and pour point par. -2.6.4(1)).

Precision: The same limits as se t forth in ASTM or Federal Test Method or loud nd pour point par. 3-2.6.4(1)) apply to this method.

(4) loud Intensity at Low Temperature Test Method : Federal Test Method 02 Ref. 8) This method describes the procedure fo r determining

the ability of hydraulic fluids or ighly efined light ubricating oils to emain free f urbidity at low temperatures.

A sample of the fluid and a standard are stored at -65°F or ower s pecified y he purchaser) or

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AMCP 706-123

TABLE -4. FLASH POINT RE Q U I RE M E N T OF FIVE MILITARY SPECIFICATION FLUIDS

Specification Fluid Type U se Flash Point, °F , m in MIL-H-5606B Petroleum Aircraft 200 MIL-H-8446B Nonpetroleum Aircraft 395 MIL-H-13866B Petroleum Artillery 210 W-B-680a Nonpetroleum Automotive 179.6 MIL-H-27601A Petroleum Aircraft 360

TEST FLAME APPLICATOR

-THERMOMETER

-TEST CUP

HEATER FLAME-TYPE OR ELECTRIC RESISTANCE-TYPE)

Fig. 3-22. Cleveland Open C up Flash nd Fire Poin t Test Apparatus

Precision : Results should not be considered suspect unless they differ by more than the following amounts:

(a ) epeatability. °F (b) eproducibility. Below 55°F-6°F

55°F or bove-4°F (3 ) Pensky-Martens Closed Cup Tester Method Test Methods : Federal Test Method 102 Ref. 43)

ASTM D-93-66 Ref. 4) These methods describe procedures for the determi-

nation of the lash point of fuel oils, ubricating ils, suspensions of solids, liquids that tend to form a surface film under test conditions, nd other liquids, with he Pensky-Martens Closed Cup Tester.

The sample is placed in the cu p of the tester; the lid closed; and the sample heated at a slow, onstant ate with continual stirring. A small flame is directed nto the cup at 5° F intervals with simultaneous interruption of stirring. The test flame is pplied by operating he

mechanism n he cover that pens a hutter, owers the test flame through the opening into the vapor space of the cup in 0. 5 sec, leaves the flame in place for sec, and quickly etracts he flame and closes he shutter. The lash point s ecorded as he temperature of the sample at he time the test flame application causes a distinct lash n he interior of the cup.


Material

Suspen- sion of Solids

A ll Others

Flash Point

Range 95° to 10°F

Below 20°F

Above 220°F

Repeatability

4° F

4° F 10T

Reproducibility

6°F

6°F 15°F

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AMCP 706-123

3-2.7.1.2 Significance of Flash and Fire Points

Petroleum iquids do no t burn as such, but n eneral, must first be vaporized. The flash and fire points are measures of the minimum emperature t which sufficient vapor will be given off from the liquid so that a combustible mixture of air and vapor is obtained. n

this manner, the relative fire and explosion hazard can be estimated from he flash nd ire points. Flash and fire points are also useful for evaluation of

used liquids. If a liquid undergoes a rise in flash or fire point while n ervice, oss of the ighter ractions by evaporation is indicated. A lower flash or fire point is an indication that the liquid ha s become contaminated with more olatile product such s uel) or hat some of the heavier fractions av e broken down. The flash nd ire points re lso ids n stablishing he identity of unknown petroleum products.

3-2.7.2 Flammability Tests Under Simulated

Service Conditions

There are many complex factors involved in assess- ing he lammability of hydraulic luids, nd o ne single est an e se d o valuate al l of the types of liquids under all of the expected conditions of use. The flash and fire points are laboratory tests that bear little resemblance to actual operating conditions. A s a result, several ifferent methods or testing the flammability of iquids were eveloped. ost of hese ests were designed o imulate onditions n ircraft esulting from a broken hydraulic line spraying liquid onto vari- ou s sources of ignition. Although the tests were developed primarily for the aircraft industry, they are useful in an y industry where hydraulic liquids are exposed to ignition ources. Three of the more common of these tests-the spray ignition, the hot manifold or hot surface ignition, and the incendiary gun fire test-are described in MIL-F-7100, Fluid, Hydraulic, Nonflammable, Air- craft (Ref. 45), an early specification for a fire-resistant hydraulic fluid. It was issued December 950 and cancelled February 1958. No products were ever produced that conformed to the specification. The fire-resistance tests in the specification (described briefly here) are still used y many ompanies nvolved n hydraulic luid work, although they vary from company to company.

Other tests are described in the literature, in various Military Specifications, and in ASTM special publica- tions. any of these ests re imilar n ature but differ in their apparatus and procedures. A major problem confronting industry today is the lack of test standardization nd nterpretation f est esults o de - quately measure ire esistance of fluids. A eview of 3-24

the general types of tests and procedures and the efforts towards standardization s given n Ref. 6.

(1 ) pray Ignition ests There are two versions of this test-the high-pressure

spray gnition est nd he ow-pressure pray gnition est.

(a) igh-pressure pray est MIL-F-7100( R ef.

45)): he liquid is pressurized to ,000 psi with nitrogen and forced through an orifice 0.0145 in. n diameter. Attempts are made to obtain ignition y pplication f n xy-acetylene torch flame at various standard distances fromthe nozzle. At each position, a report is made as to whether or no t the fluid will ignite, will flash with difficulty, or flashes readily. If flashing ccurs, he istance rom he rifice t which the ignition or flashing is carried downstream from the test lame area, nd whether the flashing is self-extinguishing or results in a sustained ire, re lso eported. pictorial

sketch of the high-pressure spray ignition test apparatus s shown n ig . -23. (b) ow-pressure Spray es t Ref. ): A ire s

started n metal an illed with il-soaked rags and s allowed o burn. The liquid to be tested s prayed owards he ire rom he reservoir of an ordinary paint pray machine several feet from the fire. The increased intensity of the fire is then used as a measure of the flammability of the iquid. A pictorial ketch of he ow-pressure pray gnition est p- paratus is shown n ig . -24.

An lternative ow-pressure pray gnition est as been developed by Rowand and Sargent (Ref. 46). This method uses an airless paint spray gun. The gun generates a flat, well-defined atomized spray by pumping the liquid onto igh-speed otating isk which propels the liquid in the form of small droplets through a slot in the side of the gun. A glass blower's torch 4 in. fromthe nozzle is the ignition source. The amount of flame produced in the spray is used as a measure of the flammability of the liquid. This method has the advantages of requiring only electricity, source of ignition, nd can be performed n a aboratory ood.

(2 ) ot Manifold Ignition Test (MIL-F-7100 (Ref. 45))

The liquid is allowed to drop at a specified ate on a simulated aircraft manifold heated to approximately 1300°F. The ignition of the liquid and the carrying of the lame o he an elow he manifold re se d s measures of the flammability of the liquid. Variations of he est nvolve aising or owering he manifold

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A M C P 706-1 23

-FLUID RESERVOIR

PRESSURE GAGE

OXY-ACETYLENE TORCH

FLUID SPRAY

HYDRAULIC STRUT

PRESSURE SOURCE

Fig. 3-23. High-pressure Spray Ignition Test Apparatus

PA N OF BURNING RAGS

FLUID SPRAY

PAINT SPRAY G U N

A IR SUPPLY

Fig. 3-24. Low-pressure Spray Ignition Test Apparatus

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A M C P 706-123

temperature until ignition occurs or until the limits of the apparatus have been exceeded. This variation ro - vides an indication of the spontaneous ignition temperature of liquids contacting heated steel surfaces in the presence of large amounts of air. A pictorial sketch of the hot manifold spray ignition test apparatus is shown in ig . -25.

(3 ) ncendiary Gun Fire Tests (MIL-F-7100 Ref. 45))

The liquid is placed in a 3 ft long, 5/8 in . OD aluminum alloy tube and pressurized to 1,000 psi with nitrogen. A ca l .3 0 incendiary bullet is fired from a range of 50 yd into the tube. Observations for burning or explosion of the liquid are made and are reported as a measure of the flammability of the liquid.

(4) ompression gnition It as een ound hat high-pressure ir uddenly

expanding nto onfined pace ontaining rganic matter uch s ydraulic luid an ause gnition

and/or xplosion, depending n he ate of pressure release, volume of air, and quantity of organic material. The phenomenon of compression gnition an e m- portant n generating ires n hydraulic ystems. Ac- cumulators, ressure age's, nd ther losed-end equipment are especially susceptible to this phenomenon. Two basic tests have been developed to determine the ompression gnition haracteristics of hydraulic fluids-the diesel engine test and the shock tube or piping system test.

(a) iesel Engine Compression gnition: This est is described in MIL-H-19475 (Ref. 47), a Mili- tary Specification for hydraulic fluids for Na- val ircraft atapult aunching ystems. he test s a modification of the ASTM CFR Ce- tane ating ngine est escribed n STM Manual of Engine es t Methods for Rating Fuels. A ample of the iquid s injected nto a variable compression iesel engine, nd he

DROPS OF LUID ONTO MANIFOLD

FLUID SUPPLY TUBE FIRE SHIELD

HEATER

(INSIDE TUBE) MANIFOLD TUBE

DRIP PAN

Fig. 3 -25 . Hot Manifold Ignition Test Apparatus

3-26

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AMCP 706-1 23

engine is thenturnedover at various compression ratios. The lowest compression ratio for combustion of the liquid is reported as a measure of he luid's lammability. he igher he compression atio, he more esistant he iquid s to compression gnition,

(b) hock Tube or Piping System Test: This test is

described in MIL-H-22072 (Ref. 48) for a fire- resistant hydraulic luid. mall mount of steel wool oaked with the iquid s placed t the closed end of a pipe. By use of high-pressure air and a fast opening valve, a shock wave is ntroduced nd irected ow n he ipe. Combustion of the liquid on the steel wool ca n be determined by a rapid rise in temperature of the steel wool or by examination at the end of the est. everal epeat ests re onducted, and the results are reported as the ratio of the number of times that fire occurred to the num- be r of tests tried at a given temperature. The

fewer times the liquid burns, the more resistant it is to compression ignition. Reproducible re - sults have been difficult to obtain in this test.

3-2.7.3 Effects of Evaporation on

Flammability (Pipe Cleaner Test)

Test Method : Federal Test Method 52 (Ref. 9) This method s se d or determining he ffect of

evaporation on the flammability of a liquid petroleum product. A pipe cleaner, soaked with the fluid, is passed repeatedly hrough flame at ate of 25 ycles per minute and the number of passes required fo r ignition is noted. The fluid is then stored in an oven for the time and at the temperature required by the fluid specification, and its flammability is rechecked. Four repeats of the test are made before and after heating in the oven. The results are reported as the average number of cycles necessary for a self-sustaining flame to be achieved on the pipe cleaner both before and after partial evaporation n he ven. A ketch of the est pparatus s shown n ig. -26.

3-2.7.4 Autoignition Temperature

The autoignition temperature (AIT)-often called the spontaneous gnition emperature SIT)-is hat emperature at which a flame ca n be obtained without an external ource of ignition. t hould ot e confused with lash r ire oints hich ely pon gnition source. Autoignition emperature s etermined y

PIPE 120 D E G CLEAN E R <

,

l'A TO

. 4 RADIUS

OSCILLATING DEVICE /

BURNER

<

DIMENSIONS N NCHES

Fig. 3-26 . es t Apparatus fo r th e Pipe Cleaner Evap- orat ion Tes t

ASTM D-2155-66 Ref. 0). mall ample of he

liquid o e ested s njected, with hypodermic y- ringe, into a heated glass flask containing air. The contents of the flask are observed in a darkened room fo r 5 min following injection of the sample or until ignition occurs. Ignition is evidenced by the sudden appearance of a flame inside the flask. The lowest emperature at which autoignition occurs is taken as the autoignition temperature of the product in air at atmosphere pressure. The time lag between injection and ignition is also reported. ross-sectional ketch f he IT p- paratus is shown n Fig 3-27.

A ew est procedure is expected o be ncluded n the evised dition of Federal Test Method Standard 791a. The ew procedure will e designated Method 5050 and entitled "Autogenous Ignition at Reduced or Elevated Pressure". The temperature determined with this test procedure is sometimes referred to as the reaction hreshold emperature.

The autoignition emperature is a aboratory measurement and is very sensitive to the procedure used in its determination. t as een hown hat n practice autoignition depends on many factors, such as the nature of the surface contacting the liquids, the composition of the combustible air mixture, and the pressure at the area of contact. Researchers at the U. S. Bureau of Mines (Ref. 1) have found that the AIT of a MIL-O- 5606 iquid ncreases ppreciably with decrease n environmental ressure elow ne tmosphere ut changes little with increasing environmental pressures above on e atmosphere (Fig. -28). Not all iquids will have the marked change in slope of the AIT/pressure curve near atmospheric pressure shown n ig. -28.

3-27

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AMCP 706-1 23

ERLENMEYER FLASK

200CC

THERMOCOUPLE

HEATERS

INSULATION

Fig. 3-27 . Autoignit ion Temperature Test Apparatus

Some liquids will have a gradual decrease in minimum spontaneous gnition emperature ith ressure n- crease and may or may no t exhibit a slope change near

on e atmosphere. For example, Fig. 3-29 shows that the AIT of a chlorinated phenyl methyl silicone iquid is essentially a linear function of pressure. Figs. -28 and 3-29 lso show that he nature and ype of surface in contact with these liquids have little or no effect on the change in AIT with ressure. t has also been ound (Ref. 52 ) that the AIT generally decreases with increasing environmental oxygen content see ig . -30).

3-2.7.5 Fire-resistant Liquids

The development of liquids that are inflammable or highly ire-resistant is he rea of hydraulic luid e- search hat is receiving the greatest ttention. A s late as 1950 fire-resistant hydraulic fluids were uncommon. For reasons of safety, nsurance companies nd Gov- ernment nd ndustrial afety gencies ave n- couraged the use of fire-resistant fluids in Government, industrial, nd gricultural quipment. ire-resistant liquids should not be confused with high-temperature liquids. A ire-resistant iquid will not burn asily. A high-temperature iquid will not ignificantly hange its properties at high temperatures". Water is a fire- resistant liquid but it is not a high-temperature liquid.

One of the fundamental properties of petroleum liquids is their flammability. Although he flammability

characteristics of petroleum liquids can be modified by the use of special refining procedures (Ref. 0) and/or the se of additives, luids of this ype av e hown considerable improvement in fire resistance over MIL- H-5606B type hydraulic fluids (Ref. 55). Other categories of fire-resistant iquids re ynthetic, water ase,

3-28

and emulsion-type. A complete discussion of the vari- ou s types is beyond the scopeof this text and the discussion here will be limited.

(1 ) ynthetics: A wide ariety of synthetic iquids have een nvestigated s andidate hydraulic luids, and certain types have been adopted and specifications written (see Chapter 4). om e of the typical classes of fluids under investigation are phosphate esters, halogenated hydrocarbons, silicones, and silicates. A detailed discussion of synthetic fluids can be found in Refs. 3, 54 , nd 5.

(2 ) ater-glycol: Water-glycol ase ire-resistant liquids are solutions of from 35 to 50 percent water in ethylene or propylene lycol, which re hickened, f necessary, to a higher viscosity by adding a water-solu-

ble polyglycol. The fire resistance of these liquids is due entirely to the presence of water. They were originally developed for use in military equipment but have been used extensively in industrial equipment.

(3 ) mulsions: Emulsion-type hydraulic luids re multiphase systems containing tw o liquids, such as oil and ater, hich re ot sually utually oluble. Water-in-oil emulsions have found wide acceptance as industrial hydraulic fluids. The emulsions contain up to 40 percent water which acts as a snuffer to render the liquid ire-resistant.

3-2.8 VOLATILITY

A ll iquids end o vaporize when hey re eated. The volatility of a liquid describes the degree and rate at hich t ill aporize nder iven onditions f

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AMCP 706-123

MINIMUM S P ONTANEOUS IGNITION TEMPERATURE, F o o o

o o o

o o o 00

o o o

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0) o Q tUJ CO C D

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3-29

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w o

V 600

J- < G£ LU

5 50 0 LU 1 —

z 0 I—

z o 40 0 CO D 0 LU z < H- z 300

o Q_ CO

53 5z 200 5

i—r TT

j _ L _ L

T I |

LEGEND

Symbo Surface

X Aluminum

V Beryllium copper

D Copper

A Magnesium

• Pyrex

o Stainless steel

+ Titanium

I J I I I I 0.2 0.4

.6 0.8

PRESSURE, AT M O S P H E R E S B S O L U T E

8 10

1100

5

z 1000 5

c_ 5

oo

900 -a o z — 1 >

800 z m o c oo

700 o z — 1

600 o z — 1

m

500 5

m =*3 > — 1

400 C

20

Fig. 3-29• pontaneous Ignition Temperature of a Chlorinated Phenyl Methyl Silicone in Air in Contact With Various Surfaces As a Function of Test Chamber Pre" r e5

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420

50

0

0 OXYGEN CONCENTRATION, VOLUME PERCENT

Fig. 3-30. pontaneous Ignition Temperature of Seven Hydraulic Fluids at Atmospher ic Pressure in Contac t With a Pyrex Glass Surface A s a Funct ion of xygen Concentrat ion52

100

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AMCP 706-123

temperature and pressure. It is desirable that a hydraulic fluid have low volatility. Vaporization of a liquid in service can result in pump damage through cavitation and a reduction in efficiency. There are three characteristics generally used to indicate the volatility characteristics f iquid-vapor ressure, oiling oint, nd evaporation loss. A ll three are different aspects of the volatility of a liquid.

3-2.8.1 Vapor Pressure

The pressure exerted by a vapor which is in equilibrium with the liquid is known as vapor pressure. For a given liquid, this pressure is a function only of temperature. The more volatile the liquid, he higher the vapor pressure at a specified temperature and the faster the vaporization.

The vapor pressure or pure iquid s physical property of the iquid or a iven emperature. How- ever, most hydraulic fluids are mixtures of several components. The vapor pressure of the mixture is a composite alue hat eflects he ombined ffects of the individual components. Theoretically, he vapor pressure of the mixture can be calculated from knowledge of the vapor pressures of the ndividual omponents and heir mole fractions.

Numerous methods have been developed for determining the vapor pressure of pure fluids. Several of the more ommon est methods re he soteniscope, as saturation methods, nd effusion methods. The use of these methods to determine the vapor pressure of mixtures, uch s hydraulic luids, an ntroduce rrors, and t s difficult o obtain ccurate vapor pressure data. Of the above methods, the isoteniscope is probably he os t ommonly sed. escriptions f he isoteniscope technique and apparatus can be found n Refs. 6 and 7. However, standardized test procedure ha s not been adopted, and the apparatus and test procedure vary slightly in different laboratories. When the vapor pressure s presented, t s requently he vapor pressure of the ase iquid. A graph of vapor pressure vs temperature for some of the more common types of hydraulic fluids is shown in Fig. 3-31 (Ref. 58). The vapor pressures of specific hydraulic luids may differ from those of the examples shown in Fig. -31. In an homologous series of liquids, the vapor pressures of he ndividual iquids ary nversely ith heir molecular weights. ig . -32 is a graph of vapor pressure s emperature or everal ypes of liquids nd exemplifies the differences in the vapor pressures of two petroleum as e hydraulic luids MIL-H-5606B nd MIL-H-27601A).

3-32

An pparatus as een eveloped or determining the vapor pressure of low-volatility solids and liquids. The apparatus can determine absolute vapor pressures at temperatures up to 1000°F, in a very short period of time, nd ith elatively imple quipment. he method is based on the kinetic theory of gases, which states hat the weight loss of a material pe r unit time is proportional o he vapor pressure of the material (Ref. ).

A tentative standard test method (Ref. 9) ha s been adopted by ASTM for determining the vapor pressure of etroleum roducts hat re onviscous. he method involves injecting a sample of the liquid into a glass bulb that ha s been evacuated. The rise in pressure in the bulb, esulting from the sample introduction, is the um of the vapor pressure of the sample nd he partial pressure of dissolved air, practically al l of which comes out of solution.

The apor pressure of hydraulic luids nd ther low-volatility liquids is usually expressed in millimeters of mercury. The vapor pressure of more olatile products such as gasoline and solvents is often expressed as the Reid vapor pressure. The Reid vapor pressure is approximately the vapor pressure in pounds per square inch absolute. The method of measuring the Reid vapor pressure of a iquid s described y ASTM D-323-58 (Ref. 60 ) and Federal Test Method 1201.6 (Ref. 61). It is determined by placing a sample of the fuel chilled to 2° to 40°F) n sealed bomb with air at mbient pressure and 00°F and measuring the change of pressure in the bomb. The Reid vapor pressure is a standard measure of volatility in the fuels and solvents industry.

3-2.8.2 Boiling Point

The boiling point becomes important only for relatively pure ompounds nd s not enerally se d o describe liquids which are mixtures. It is determined by extrapolation of vapor pressure data or by simply heating a liquid until it refluxes or distills. For liquids that are ixtures, ange f oiling oints s btained rather han ingle oiling oint. The oiling point temperature range of petroleum products is normally determined y STM -86-66, Distillation f e- troleum Products". A 00-ml sample of the product is distilled n prescribed manner, depending upon ts nature. Temperature readings taken are the initial boiling emperature of the ample, he maximum oiling temperature, and other temperatures as prescribed per- centages f the distilled product re ecovered n condensing nit.

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AMCP 706-12?

X

w cd D

w cd OH

cd O CL ,

iuuu

100

10

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200 300 00 TEMPERATURE, °F

500

Fig. 3-32. Vapor Pressure vs Temperature of Several Types of Hydraul ic Fluids

(1 ) Evaporation Tackiness Test): Test Method : Federal Test Method 53 Ref. 2) This est ethod s ntended or hydraulic luids

which ontain iscosity mprovers such s cryloid polymers). t erves s eans f determining he tackiness of the viscosity improver after the base liquid has been evaporated.

A lass lide s dipped n ample of the luid t room temperature and then suspended in an oven. The

oven is heated to the temperature for the period of time called fo r in the fluid specification. The condition of the fluid n the slide is reported. A fluid is considered to have assed he est f it s till ily nd not hardior tacky.

(2 ) Evaporation Loss: Test Methods : Federal Test Method 351.2 (Ref. 3)

ASTM D-972-56 (Ref. 4)

3-34

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AMCP 706-123

These ethods escribe est rocedure or he determination of evaporation loss of lubricating greases and ils t ny emperature n he ange f 10° to 30(fF.

A sample of the fluid is placed in a special container in a bath maintained at the test temperature (see Fig. 3-33). Heated air is passed over the surface of the fluid

for 22 hours. The evaporation loss is expressed in percent weight loss of the sample. Precision :

(a) epeatability. .5 percent of the mean (b) eproducibility. 0 percent of the mean

(3 ) vaporation Loss-High Temperature: Test Method : Federal Test Method 50 (Ref. 5) This method is the same as the evaporation loss of

paragraph (2 ) above except for the temperatures for the test nd he pparatus. Evaporation oss data an e obtained t ny emperature n he ange f 10° to 000T.

3-2.9 DENSITY, SPECIFIC GRAVITY, A N D

THERMAL EXPANSION

Liquids expand in volume, with a corresponding de - crease in density, when heated. The amount of expansion varies with each iquid and is a basic property of

that iquid. The density and the coefficient of cubical expansion are closely related because the coefficient of cubical xpansion efines he change n volume and therefore the change in the density) ith hange in emperature.

3-2.9.1 Density

The density is defined as the mass of a unit volumeof material at an y given temperature and pressure. n the metric system these units are grams per cubic centimeter. t is frequently more convenient to express the density at a given temperature and pressure as the relative density, which is defined by

relative density — Po

(3-21) where

p = ensity at given emperature

and pressure p = ensity at reference temperature and pressure (standard conditions of 25°C (77°F) and 60 mm Hg are frequently sed)

AIR OUTLET

AIR NLET

BATH LEVEL

FLUID SAMPLE

Fig. -33 . Cut-away Sketch of th e Evaporat ion Loss Apparatus Used in A S T M D- 9 7 2 Test M e th o d

3-35

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AMCP 706-123

Density is of great importance when calculating flow of hydraulic fluids through components such as valves, pumps, and motors. The density enters into the flow- energy equations and changes in density will affect the results obtained from the equations. High-density liquids may enerally be eliminated rom consideration because of weight limitations imposed on the hydraulic system, especially in airborne systems.

Density is a function of both temperature and pressure. A n increase in temperature produces a decrease in ensity. hanges n ensity ue o xpansion f fluids etween he minimum nd maximum ystem temperature can cause serious malfunctions unless considered in the design of a system. For a high-temperature aircraft or missile hydraulic system operating between the extreme temperatures of-65° and 500°F, the fluid volume can be expected to change up to 35 percent (Ref. 6). Graphs of density s emperature for several types of fluids are shown in Figs. 3-34 and 3-35.

Density lso aries with ressure. An ncrease n pressure produces an increase in density. However, the normal pressures encountered in most hydraulic systems re ot igh nough o roduce ignificant changes in density. A graph of relative density vs pressure or ypical IL-H-5606B ydraulic luid s shown in Fig. 3-36 (Ref. 67). Pressures as high as 5000

psi which s higher than the pressures normally encountered n ydraulic ystems) roduce hanges f less han .5 ercent n he ensity f the MIL-H- 5606B fluid. As the pressures are increased to very high levels, large and significant changes in density are produced. Th e ASME Pressure-Viscosity Report (Ref. 21) gives density data on several liquids at pressures up to 150,000 psi. Wilson (Ref. 22) reports density-pressure data (see Fig. -37) on MLO-60-50 fluid (an ester of trimethylolpropane, thebase fluid of MIL-L-9236 oil). Both of these reports indicate that changes in density up to 3 5 percent are produced at these higher pressures.

u b0

1.5

1.4

1.3

1.2

> 1.1 i- > i—

Z

a i.o

0.9

0.7

T

VRINATEDJ££22^*BON

j ^^ TE ESTF R

WATER-G L YCOL

JXLICONE

" 8MULSIO?

180 200 00 120 140 loO TEMPERATURE, °F

Fig. 3-34. ensity vs Temperature of Typical Fluids (Approximate) [From: F. D. Yeaple, Hydraulic and Pneumatic Power an d Contro^.Used by permission of McGraw-Hill, Inc.] 3-36

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AMCP 706-123

1.96

1.88

1.80

1.72

1.64

1.56

1.48

1.40 o u bO

„ 1.32

to 2 1.24 W Q

1.16

1.08 -

1.00

0.92 -

0.84

0.76

0.68

1—~T T

IC O 200 300 400 500

TEMPERATURE, F

Fig. 3-35. ensity vs Temperature of Several Types of Hydraulic Fluids at Atmospheric Pressure

3-37

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AMCP 706-123

OH

1.004 —

1.000 1000 000 000

PRESSURE, SIG

4000 5000

Fig. 3-36. elative Density vs Pressure at Several Temperatures of a Typica l Fluid Conforming to MIL-H-5606B 67

Researchers at Rock Island Arsenal have conducted extensive studies on the effect of hydraulic fluid density on he erformance f rtillery ecoil echanisms (Refs. 8, 9). They determined that using a liquid of higher ensity esulted n horter ecoil engths nd higher pressures. Shorter recoil length may be of value in ecoil ystems operating n onfined reas uch s combat vehicles, but consideration must be given to the higher pressures involved.

3-2.9.2 Specific Gravity

The specific gravity of a liquid is defined as the ratio of the mass of a unit volume of the iquid t iven temperature to that of an equal volume of pure water at tandard emperature. The tw o temperatures are not necessarily the same and both must be indicated in specific gravity data. The common procedure is to have both temperatures equal 0° F (15.6°C) and report the data as "specific gravity at 60/60°F" (the numerator is the temperature of the fluid and the denominator is the reference temperature of the water). Specific gravity, a

dimensionless ratio, is sometimes erroneously used in- terchangeably with density. They are not the same and should not e onfused. They re numerically qual only when water, at 4°C (39.2°F) and 76 0 mm Hg is the reference liquid. At those conditions, gram of water occupies millihter or 1.000027 cubic centimeters. The small difference is usually neglected and the terms mil- liliters nd ubic entimeters re onsidered nterchangeable. pecific gravity is as pressure sensitive as density nd n ncrease n pressure will produce n increase in pecific gravity.

Specific gravity is very useful in the commercial as- pect of the petroleum industry. Almost all iquid e- troleum products re packed y volume-barrels, al- lons, etc. However, they are frequently shipped or sold on weight asis nd he pecific gravity rovides convenient onversion actor. pecific ravity s lso useful in determining fuel loads, determining combustion efficiencies, and in other processes that depend on specific ravities of the materials sed. The ange of specific gravities for petroleum products is about 0.700 to .150.

3-38

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AMCP 706-123

0.95 EXPERIMENTALLY DETERMINED

0 . 9 0 ,

EXTRAPOLATED

1 20 1 1 1 40

0

0

PRESSURE, SIG I0" 3

100

Fig. 3-37 . ensity vs Pressure at Several Temperatures fo r MLO-60-50 Fluid (an

120

ester of t r imethylolpropane) 22

3-39

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AMCP 706-123

3-2.9.3 A P I Gravity

Several methods have been developed to express the weight-volume relationship of a liquid as a whole number. O ne such method is the American Petroleum Insti- tute (API) Gravity Scale. The scale is based on specific gravity at 60°F (15.6°C) and reports specific gravity as

API degrees from 0 to 00. The API scale is an arbitrary scale with zero corresponding to a specific gravity of 1.076 and 00 corresponding to a specific gravity of 0.6762. herefore, he higher he PI ravity, he lower the specific gravity of a liquid and the less dense the liquid. API gravity is related to specific gravity by the formula

API Gravity (degrees)

41.5

specific gravity 60/60°F 131.5 (3-22)

For xample, water with pecific gravity of .000, 60/60T, has an API Gravity of 10.0.

3-2.9.4 Coefficient of Cubical xpansion

The coefficient of cubical expansion (often called the coefficient of thermal expansion) expresses the change in volume per unit volume with temperature. It has the units of vol/(vol-temperature). Thermal xpansion s always accompanied by a change in density or specific gravity and the coefficient of expansion is usually calculated rom density or pecific gravity) data deter-

mined at various temperatures. t is an average value over the actual temperature range ofdetermination and is not ecessarily inear unction. The emperature range where he measurements re made hould e stated in all data. Graphs of thermal expansion vs temperature or hree ydraulic luids re hown n Fig.3-38.

0.00058 -

fe

Z o 2

X - W

3 EQ D u

O

H

Z m IHU 1 — I

w O U

0.00054 -

0.00050 -

0.00046 -

0.00042 100 200 300 400 TEMPERATURE, °F

Fig. 3-38. Coefficient of Cubical Expansion vs Temper ature of Several Types of Hydraulic Fluids

A sample of the fluid is brought to the proper test temperature nd laced n lass ylinder. An API hydrometer is floated in the fluid and the API Gravity in egrees is read from the hydrometer. The temperature f he ample s oted. ll readings re or rected o PI ravity t 0° F y eans f standard tables published by ASTM and the Institute of Petroleum Ref. 2).

500

3-2.9.5 Test Methods fo r Density an d Specific Gravity

(1 ) API Gravity:

Test Methods : Federal Test Method 401.5 (Ref. 70 ) ASTM D-287-64 (Ref. 1) These methods describe a procedure for determina-

tion, by means of a glass hydrometer, *the API Gravity of petroleum products normally handled as liquids and having a Reid vapor pressure of 26 si or less.

Precision : The criteria which should be followed for judging esults btained t emperatures f 0"±18°F are hat results should not be considered suspect unless they differ by more than the following amounts:

(a) epeatability. .2 ° API

(b) Reproducibility. .5 ° API

A hydrometer is a floating instrument for determing the specific gravity of luids rom knowledge of he pecific gravity of he hydrometer and he mount of the loating hydrometer hat x- tends bove he urface of the luid.

3-40

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AMCP 706-123

(2 ) ensity and Specific Gravity - Lipkin Bicapil- lary Pycnometer

Test Methods : Federal Test Method 402.2 (Ref. 3) ASTM D-941-55 Ref. 4)

These methods describe the procedure fo r the measurement of density of hydrocarbon materials that can be normally andled s iquids t he pecified est temperatures of 20° and 25°C (68° and 77°F). Applica- tion is. restricted to liquids having vapor pressures less than 60 0 mm Hg (approximately 0. 8 atmospheres) and viscosities ess han 5-20 entistokes t 0°C. wo procedures re provided-Procedure A or pure om - pounds nd mixtures not ighly olatile, nd Proce- dure B for highly volatile mixtures. These test methods also rovide alculation rocedure or onverting density o specific ravity.

A sample of the liquid is drawn into the bicapillary pycnometer shown n ig . -39) nd weighed. t s then placed in a bath at the specified temperature and

allowed to come to equilibrium. The height of the fluid in each arm is noted and the volume is determined from the pycnometer calibration. The density nd he pe - cific gravity re then alculated rom he weight nd volume of the fluid sample.


(a) epeatability. .0001 g/ml (b) eproducibility. .0002 g/ml

•il

GRADUATIONS SHORT LINES AT EACH LONGER LINES AT EACH NUMBERED AS SHOWN

m m 5 m

(3 ) ensity and Specific Gravity-Bingham Pycnom- eter

Test Method : ASTM D-1217-54 (Ref. 5) This method describes the procedure for determining

the density of pure hydrocarbons or petroleum distil- lates oiling between 0° and 60°C 194° and 30°F) that can be handled normally as liquids at 20°and25°C (68° nd

7°F).

lso provided s

a calculation

rocedure fo r conversion of density to specific ravity. The fluid sample is introduced into the pycnometer

(shown in Fig. 3-40), allowed to come to equilibrium at the test temperature, and weighed. The specific gravity or density is then calculated from this weight and the previously determined weight of water that is required to fill the pycnometer at he same temperature.

Precision : Results with the 25-ml Bingham pycnometer hould ot iffer y ore han he ollowing mounts:

(a) epeatability. .00002 g/ml (b) eproducibility. .00003 g/ml

n

Fig. 3-39* Lipkin Bicapillary Pycnometer fo r Determin- in g Density and Specific Gravity of Liquids

Fig. 3-40. Bingham Pycnometer fo r Determining Den- sity and Specific Gravity of Liquids

(4) Specific ravity-Hydrometer ethod

Test Method : ASTM D-1298-55 Ref. 6) This method describes a procedure for the determination, by means of a glass hydrometer, of the specific gravity f rude petroleum nd petroleum roducts normally handled as liquids and having a Reid vapor pressure of 26 psior less. Results are determined at 60°F or converted o alues t 0° F y means of standard

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tables published y ASTM nd he nstitute of Pe- troleum Ref. 2).

The ample s poured under prescribed onditions into lean hydrometer ylinder. The hydrometer s lowered into the sample so that it is floating freely away from the walls of the cylinder. The observed gravity is read irectly n he ydrometer cale t he oint

where the surface of the sample intersects the scale. The temperature of the sample is also measured. Precision : Results should not be considered suspect

when obtained at temperatures differing from 60°F by less than 8°F unless the specific gravity values differ by more than the following amounts:

(a ) epeatability. .0015 g/ml (b) eproducibility. .0040 g/ml

3-2.10 HEAT TRANSFER CHARACTERISTICS

The heat transfer properties of a hydraulic fluid can be very mportant o the design ngineer as most y- draulic systems are thermally inefficient. A large portion of the pressure nergy upplied o he hydraulic fluid through the pump is dissipated by friction in the valves, motors, actuators, seals, piping, and other components of the ystem. ll of this dissipated nergy becomes heat nergy nd much of it aises he iquid temperature. A knowledge of the heat transfer characteristics of the liquid then becomes essential o determine how high the temperature will rise, and what type and size of heat exchanger will be needed to maintain the liquid at a desirable temperature.

3-2.10.1 Specific Heat The pecific heat f iquid s measure of he

amount of heat iven quantity of liquid an bsorb from he system. t is defined as the heat required o raise a unit weight of liquid on e degree of temperature. The pecific eat s usually denoted y he ymbol cp r „ nd ts nits n he etric ystem re calorie/(g-°C) nd' n he nglish ystem re Btu/(lb-°F). The ubscripts p and indicate whether the determination of specific heat is made at constant pressure r t onstant olume. his istinction becomes important in gases which are highly compress- ible, but liquids are relatively incompressible by comparison nd here s ittle difference etween he wo values. n general, owever, t s common practice to determine the specific heat of liquids at constant pressure nd he ymbol „ is sed. pecific heat n he metric system is numerically equal o specific heat n the English system of units.

For iven ydraulic ystem upplying iven amount of heat to the hydraulic fluid, a liquid with a high specific heat will undergo a smaller temperature rise than will a liquid with a low specific heat. Thus a high value aids in maintaining a lower operating temperature in a system, and in some applications increases the amount of heat that may be removed from a system hot pot ithout ausing degradation of he iquid. Most petroleum-base hydraulic luids av e pecific heat between 0.4 and 0. 5 Btu/(lb-°F).

The pecific eat ncreases ith emperature or most hydraulic luids nd he temperature hould l- ways be stated with the data. A graph of specific heat vs temperature for several hydraulic fluids is shown in Fig. -41. Although specific heat varies with pressure, the hange s o mall ver he ressure anges normally ncountered n ydraulic ystems hat t is neglected.

Numerous methods have been developed to measure the specific heat (Ref. 4) . Almost all of these methods

utilize om e ype f alorimeter essentially n n- sulated flask). A known volume of the sample is placed into the flask and a known amount of heat is added to the sample. The change in temperature of the sample and the amount of heat added are both recorded. The specific heat is then calculated with corrections being made for heat losses from the calorimeter. An approxi- mation to the specific heat of petroleum liquids is given by he following equation Ref. 7)

Jds (0.388 + 0.00045 D (3-23)

where s = pecific gravity at 60/60°F T = emperature, F

3-2.10.2 Thermal Conductivity

Thermal conductivity is one measure of the ability of a material to transfer heat. Heat transfer in operating hydraulic ystems s ccomplished primarily y on - vection because of forced liquid mixing. However, thermal conductivity is ofimportance in the transfer of heat to or from physical boundaries of hydraulic systems. A liquid having igh hermal onductivity will more readily pick up heat in hot system components, such as

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0.64

0.32

0.28

0.24

CHV O^ o? v V°3 ct tf

?q - ^ S - ?^A3Ö * £ #> VJlO Ä

0.20 0

00

J. J

200

00

00

TEMPERATURE, F

500

Fig. 3 - 4 1 . Specific H eat vs Temperature of Several Types of Hydrau l ic Fluids

valves and pumps, and transfer it to cooler system components uch s heat xchangers. Liquids ommonly used in hydraulic systems generally have thermal con- ductivities at room temperature on the order of 0.06 to

0.09 Btu/(hrXfl*)(T/ft). and these values normally de - crease ppreciably with emperature ncreases. Con- version f nits rom he nglish ystem n Btu/(hr)(fl?)CF/ft) o he etric ystem n cal/(sec)(cm 2X°C/cm) can be made by multiplying the values n he English ystem y .00413. A graph of

thermal onductivity f everal ydraulic luids s shown in ig . -42.

Several methods of measuring thermal conductivity

have been developed Ref. ). Most of these methods consist of placing the sample fluidbetween two surfaces of known rea nd heating ne urface o known temperature. The temperature of the other surface and the ate of heat ransfer re bserved. he hermal conductivity is then calculated.

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0.084

0.080

0.076

4-

? 0.072

s-

C Q

OO

on

0.068

0.064

0.060

U 0.056

0.052

0.048

0.044

0.040

Si ^LUOK

CHLOR l0 LUOROCARBON

1 100 200

00

TEMPERATURE, F 400 500

Fig. 3-42. Thermal Conductivity vs Temperature of Several Types of Hydraulic Fluids

3-2.11 COMPRESSIBILITY A ND BU L K M O D U L U S

3-2.11.1 Compressibility

Most liquids are thought of as being incompressible.

In eneral, owever, ll iquids re ompressible o some extent. Compressibility of a liquid causes the liquid o ct much ike tiff spring. The pring-like action can produce delays in control signals, useenergy in compressing thefluid, and affect the gain or amplifi- cation of servo systems (Ref. 78). It is usually desirable

to have the hydraulic fluid as stiff as possible, or stated in anothermanner, to have the compressibility as small as possible.

Th e oefficient f compressibility s he ractional change in a unit volume of liquid per unit change of pressure. f he ompression rocess s arried ut slowly so that sufficient heat is removed to maintain a constant temperature, the resultant value of compressibility is the isothermal compressibility given by (Ref. 4)

Vo \dp) t (3-24)

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where Cf = sothermal compressibility V0 = nitial volume

& V/dp) = ate of change of volume with pressure at constant temperature

If the compression takes place so that adiabatic con-

ditions exist (no heat extracted), the result is the isentropic compressibility given by (Ref. )

^ o lap) (3-25)

where C,=

y a =

isentropic compressibility initial volume

(d V/dp)s — a te of change of volume with pressure (at constant ntropy)

In the English system, compressibility has the units of volume/(volume-psi). It is common practice to can- ce l out the volume terms and express compressibility as (psi)~. A graph of percent volume compression vs pressure of several liquids is shown in Fig. -4 3 Ref. 8).

0 5

0 15

PRESSURE, PSIG 0

20 25 -3

Fig. 3-43 . Fluid Percent Volume Compression vs

Pressure of Typica l Fluids

Differences xist etween he sothermal nd he isentropic ompressibility. or normal ituations n- countered in hydraulic systems, they are not sufficient to warrant differentiation. However, t igh temperatures or pressures, or for certain liquids, the differences can ecome ignificant nd, when dded o he wide

variations ue to temperature and pressure, system can be driven beyond cceptable tability imits (Ref. 6).

3-2.11.2 Bulk Modulus

Bulk modulus, he eciprocal of compressibility, s used in design calculations for hydraulic systems. The units of bulk modulus re si. he higher he bulk modulus, the less elastic or the suffer the liquid. High bulk odulus alues re sually desirable ince he result s a more stable and ess elastic system.

Like compressibility, bulk modulus can be either isothermal or adiabiatic. The isothermal bulk modulus is sometimes eferred o s he tatic bulk modulus e- cause it is determined at a constant temperature. The isentropic or adiabatic bulk modulus is sometimes referred to as the dynamic bulk modulus. n either case, static or dynamic, bulk modulus may be reported as the secant or

the

tangent

modulus. The

names "secant" or

"tangent" efer to the relationship the values av e to the pressure-volume urve of the iquid see pars. - 2.11.2.1 nd -2.11.2.2). here re hen our ulk modulus alues possible-isothermal ecant, diabatic (isentropic) ecant, sothermal angent, nd diabatic (isentropic) tangent-and care must be exercised to select the right value for a particular application. Table 3- 5 presents the equations for the various bulk moduli. A typical graph of isothermal secant bulk modulus vs pressure is shown in ig . -44.

3-2.11.2.1 Secant Bulk Modulus

The ecant bulk modulus (frequently eferred o in the literature as mean or average modulus) is defined as he otal hange n iquid pressure divided y he total change in volume per unit volume of liquid. The secant modulus then is the slope of the secant (drawn between wo pressures) of the pressure-volume urve (see Fig. -45). t is standard practice to se t the initial pressure equal to atmospheric. The secant modulus of a iquid can be thought of as the average pressure re - quired o roduce iven olume hange er nit volume over a given pressure range.

(1 )

sothermal Secant Bulk Modulus: The isothermal secant bulk modulus Bt is the bulk modulus determined when the liquid is held at constant temperature. It is the modulus value that is applied to systems that change pressure and volume very slowly, allowing heat to flow in or out to maintain a constant emperature. This is the value of bulk modulus most often reported

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3000

Ü i—

OH

CO

W ao -,

20ÜG

1G00 —

0.005 0.010 0.015

-(AV) V

Fig. 3-45. Example Representat ion of Secan t and Tangent Bulk Modul i

is he Bridgeman method. he iquid s placed n bellows and compression of the bellows causes movement of an lectrical ontact long a slide wire. This method has the advantage of yielding a continuous plot of pressure vs volume for the experiment. This method was se d o etermine luid ompressibility n he ASME Pressure-Viscosity Report ( Ref. 21) and was also used by Wilson Ref. 2).

A method commonly used in the petroleum industry is o pressurize known volume of liquid y orcing additional liquid into the container and measuring the volume of liquid expelled when the pressure is released. This method has the disadvantage that it generates only

3-48

one datum point per xperiment, but t an e done with simple equipment and fairly apidly.

3-2.11.4.2 Sonic Bulk Modulus

Determinations of sonic bulk moduli are made utiliz-

ing ultrasonic peed measurements. everal methods have een eveloped. hese ethods determine he speed ither y direct measurement of the peed of ultrasonic waves in the fluid or indirectly by determining frequencies which result in interference of the generated wave nd he eflected wave rom he opposite

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3-2.11.4.4 Estimation of Bulk Modulus Other Methods)

Other researchers have also developed relationships for predicting the bulk moduli of liquids. Wright (Ref. 79 ) has developed a method for determining both the secant and tangent bulk modulus of petroleum oils. The

method requires knowledge of only the density of the oil at zero psig at a given temperature. By means of a series of graphs, he bulk moduli at ny pressure and the given temperatures can be easily determined. Den- sity at an elevated pressure and the given temperature can then be determined by he relationship

plpo - plB t 3-30)

where p0 = ensity at 0 psig, g/cm p= ensity at pressure p,g/cm p = ressure, sig

B * = sothermal secant bulk modulus, sig

Tichy and Winer (Ref. 80) have developed a method for he prediction of bulk moduli of silicone iquids similar o hat of Wright. Their method lso se s series of graphs to convert density at reference conditions to bulk modulus at any temperature and pressure.

3-2.12 EMULSIONS A N D OAMING N HYDRAULIC FLUIDS

An emulsion is defined as an intimate dispersion of on e liquid within another. It is a mixture of two liquids and ot olution ith ne iquid issolved n he other. A oa m s n mulsion n which he dispersed phase is ga s ather than liquid. The oaming and emulsion characteristics of a hydraulic fluid are important o ystem erformance ecause hey re mechanisms y which he luid an ick up nd ontain contaminants which can affect its properties and functional bility. he ontaminants ncountered n y- draulic systems are solid particles, ases, nd liquids. Contamination with gases can produce foams, and contamination with iquids an produce mulsions. The discussion herein will be limited basically to contamination with air (gas) and water (liquid).

3-2.12.1 Emulsion Characteristics

An emulsion is unstable and will eventually result in a separation of its components. However, he time re - quired or his eparation ay ary rom everal econds o eeks r months. he eparation im e of an emulsion formed in a hydraulic fluid is determined by the properties of the luid nd ny dditives t may contain see Chapter 5), nd by he contaminant. An emulsion of water and a hydraulic fluid is undesirable. Ease of separation of the water from the hydraulic fluid then becomes essential.

Water forms tw o types of emulsions with hydraulic fluids-oil-in-water where he water s he continuous phase and water-in-oil where the oil is the continuous phase. The common ype of emulsion orming in y- draulic luids ontaminated ith ater s n il-in- water emulsion. ince water s he ontinuous hase, there s drastic ecrease n ubricating bility, n- creased rusting, and a possibility of increased viscosity.

Some fire-resistant hydraulic fluids are formulated as water-in-oil mulsions. mulsion tability f hese fluids is, of course, equired.

Water can enter a hydraulic system in various ways. Leaks in heat exchangers, condensation of moisture in containers or ystem eservoirs, nd ccidental on - tamination are the usual methods. Once the water is in the system, it is subjected to agitation in the pump and other parts of the system where turbulent flow exists. This mixing produces n mulsion of he hydraulic fluid nd water. Water which s thus mixed with he hydraulic fluid can cause rusting, a loss of system efficiency, defective lubrication, increased leakage, and increased oxidation of the hydraulic fluid (Ref. 20). The emulsion will also affect system performance by forming sticky slimes which foul pumps; corrode cylinders and other lements of the hydraulic ystem; nd, n general, produce unsatisfactory performance.

In order to reduce the adverse effects of an oil-and- water emulsion, it is usually desirable to use a hydraulic fluid which has good water-separation characteristics. The hydraulic luid nd he water will hen eparate quickly in the system reservoir, with the water floating to the top or to the bottom, depending on the density of the hydraulic fluid.

Many materials can unction s emulsifying agents and increase the tendency of a hydraulic fluid to form an mulsion. mall oncentrations of these materials are usually most effective. Materials which act as emulsifiers can be introduced into a hydraulic system in a number of ways-as mpurities n he ase tock, s products ormed rom xidation uring se , nd s additives hich erform ther unctions ut ave

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emulsifying properties. Thus, hydraulic luid which normally has good water separation characteristics ca n be hanged while in se in he ystem o hydraulic fluid which will eadily form emulsions.

It should be pointed out that hydraulic fluids which are emulsions of water-in-oil have been proposed and used satisfactorily as fire-resistant hydraulic fluids. n

such types of hydraulic fluids it is essential that the oi l have good emulsifying properties so that the water will not readily separate from the oil. Water-in-oil emulsion hydraulic fluids are being extensively used by the Bu- reau of Mines n machines nd evices hat re pe - rated n oa l mines (Ref. 1).

3-2.12.2 Foaming Characteristics

A foam is a dispersion of a gas in a liquid. In general, foaming is undesirable in hydraulic systems. The presence of air n he hydraulic luid an ause oss of

system fficiency, efective ubrication, nd oss f fluid y verflow of the foam. Air can be introduced into hydraulic ystem n everal ways. t an ome from pen eservoirs, eakage n he suction ide of the pump, eal eakage, or be introduced when illing the system.

Much of the air in a hydraulic system will often be dissolved n he igh pressure iquid t he discharge side of the pump. The air that remains dissolved in the liquid does not create a foam. However, s he liquid enters low-pressure areas of the system, he excess air can come ou t of solution and form bubbles which can be arried with he iquid hrough he system. Foam

can also be formed in an y part of the system where the liquid experiences excessive agitation, such as in gears, bearings, alves, nd other components. f the iquid has good foam-suppressing capability, he excess bubbles will be carried to the reservoir and eleased.

Undissolved air causes irregular action of cylinders and alves ecause he iquid o onger has high degree of incompressibility. ir ubbles, he n om - pressed to a high pressure, will produce a localized high temperature. It can be shown that if air is adiabatically compressed from atmospheric pressure to 00 psi, the theoretical temperature of the air would be 485°F. At a compression of 3,000 psi, the theoretical temperature

would be 2,020°F. These high temperatures may not be noticeably eflected n aising he eservoir emperature, but will cause oxidation of the surrounding liquid film and the formation of contaminants (Ref. 0).

Foaming haracteristics re sually iscussed n terms of foaming tendency and foam stability. Foaming

tendency is a measure of the ability of a liquid to forma foam under specified conditions that would promote foaming. t s sually esirable o have as ittle tendency o foam as possible. Foam stability is a measure of the tendency of a liquid to maintain a foam once it has been established. The lower the foam stability, the faster he oam will ollapse nd elease he ntrap-

ped ir. Much like emulsion characteristics, foaming characteristics an e nfluenced y number of variables. Small amounts of contaminants and oil oxidation products of the liquid generally increase the foaming characteristics. Researchers t Rock sland Arsenal have found hat iscosity, emperature, rease ontamination, nd water ontamination ll ffect he oaming characteristics of hydraulic fluids nd iquids se d n recoil mechanisms (Ref. 82). Their data indicate a general trend, with exceptions, that increased viscosity will be accompanied by greater foaming tendency and foam stability. The liquids tested showed a decrease in foam-

ing tendency and in foaming stability with an increase in emperature. ontamination with rease n mall amounts (1 to 5 percent) produced significant increases in foaming tendency and foam stability. Contamination with water produced erratic results. Very small concentrations of water, 0.08 percent, did not have much effect. With higher concentrations of water (1 o 5 ercent), oaming endency ncreased. oam tability increased, at lower temperatures, with increased water concentration; but at the higher temperatures, the foam stability as ecreased ith he arger ercentage of water.

3-2.12.3 Tests fo r Emulsion an d Foaming Characteristics

(1 ) Emulsion Characteristics:

(a ) Emulsion Characteristics of Steam-Turbine Oils:

Test Method : ASTM D-1401-64 (Ref. 3) This method is intended fo r testing steam turbine oils

but may e se d o est iquids of other ypes. he method describes a procedure for measuring the ability of oil and water to separate from each other.

A 40 ml sample of the test liquid and 40 ml of distilled water are tirred fo r 5 min in a graduated cylinder with a flat paddle turning at ,500 rpm. The time, n multiples of in , equired or he mulsion o e reduced to 3 ml or less is reported. f the emulsion is more than 3 ml after hr, the test is discontinued and

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TABLE 3-6 .

FOAMING RE Q U I RE M E N T OF MILITARY SPECIFICATIONS

Fluid Temperature, F

Foaming Tendency Foam vol, m l, at

en d of 5-min blowing period

Foam Stability

Foam vol, m l, at en d of 10-min settling period

MIL-H-5606B

MIL-H-8446B

MIL-H-27601A

7 5

7 5

7 5

200

7 5

65 (max)

600 (foam +fluid)

15 (max)

75 (max)

75 (max)

Complete Collapse

Complete Collapse

Complete Collapse

Complete Collapse

Complete Collapse

Precision: Results should not be considered suspect

unless they differ by more than the following amounts at he end of the min blowing period:

(a ) epeatability. 0 ml or 5 percent of average (whichever is greater)

(b) eproducibility. 0 ml or 38 percent of average (whichever is greater)

3-2.13 GAS SOLUBILITY

Hydraulic fluids, like other liquids, tend to dissolve any ases hat ay e n ontact ith hem. he

amount of gas dissolved by a particular liquid depends upon the composition of the gas, the composition of the liquid, the temperature, and the pressure. At room temperature and atmospheric pressure, between nd 5 percent ir , y olume, an e ound n olution n hydraulic fluids. A distinction should be made between dissolved ases nd rapped or ntrained ases. he dissolved gases have virtually no effect on the physical properties of the liquid. They become important only when hey re volved rom olution n he orm of bubbles creating a foam or a pocket of gas in the system. Once the gas has evolved from solution, the physical properties of the iquid-gas mixture re trongly influenced by the resulting foam (Ref. 6).

The solubility of gases in liquids is generally considered o e nversely proportional o he emperature (Ref. 4) and directly proportional to the pressure. Log- log graphs of gas olubility s emperature are inear over moderate ranges of temperature (Ref. 6). Leslie 3-54

(Ref. 8) as eported hat he olubility of gases n

many ubricating ils ncreases with ising emperature. ncreases in the solubility of nitrogen in two pe - troleum oilsat 350°F over that at room temperature are shown in Fig. 3-50. This figure also shows that increasing pressure has a much greater effect on nitrogen olubility n istillate white il han does increasing temperature. In general, pressure ha s a greater effect on gas solubility than does temperature, but not for all liquids. In ig. -50, temperature is the more significant factor in he ase of the naphthenic oils. ncreases in the solubility of air with increasing pressure for some different type hydraulic fluids is given in Fig. 3-51. It should be noticed that air solubility in silicone and petroleum oils increases more rapidly with increasing pressure than it does fo r he olar ater ase r hosphate ster type oils.

Since solubility limits are affected both by temperature and pressure in a given liquid, changes in temperature and pressure occurring within the system can re - sult n issolved ases eing xpelled rom olution. Once this happens, the evolved gas bubbles can constitute up o 5 ercent f the otal iquid lus oam volume and have serious effects on the hydraulic system performance (Ref. 6). Pump delivery will be re - duced nd he pump is subject o cavitation amage. The ompressibility of the hydraulic luid-foam mixture

will be

increased, its

bulk modulus

decreased, and

control tability nd omponent ife will uffer. Even when system design has provided for such eventuality, it will still take time fo r the entrapped gas to be tran- sported back to the reservoir where it can be separated from the hydraulic fluid. Reports of hydraulic system

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z o — 1

H i—<

Q Z

>* o -J 1— 1

u o J •

i—

i— i

D Q

H rn a

-1 O 1/3

<<

z i—1 w s o B J H 1— 1

Z

0.50 -

0.40 -

0.30 -

0.20 -

0.10 -

DISTILLATE HITE IL

NAPHTHENIC IL

10

0

0 PRESSURE, SIA

Fig. -50. Nitrogen Solubility vs Pressure of T w o Petroleum Products

[From: R. . eslie, he Relation of Fluid Properties and High emperature Hydraulic Performance1* . Used by permission of ASLE]

S D

O >

E - —i

m ID

O w

0

.4

.8

.2

PRESSURE, TMOSPHERES

Fig. -51 . A ir Solubility vs Pressure of Typical Fluids

[From: . D . Yeaple, Hydraulic and Pneumatic Power and Control5 * . Used y ermission f cGraw- Hill, Inc.]

malfunctions have frequently been traced to air separation problems. Dead-ended or single line systems similar to simple hydraulic brake systems are particularly prone o ir volution nd ntrapment Ref. 6). small amount of liquid circulation built into such systems can help to relieve the problem.

3-2.14 LOW-TEMPERATURE STABILITY

3-2.14.1 General Hydraulic fluids are often stored for prolonged peri-

ods of time at low temperature. During this storage, the liquid should not undergo an y permanent changes in its properties or show evidence of gelling, crystallization, or separation of an y of its components. Gelling is the formation of jelly-like materials due to coagulation of a component or components of the liquid. Crystalliza- tion is the formation of crystals or crystalline material by a component or components of the liquid. Separa- tion is the removal from suspension or solution of components or additives in the liquid. Many specification liquids, owever, will e eemed o av e atisfactory

low-temperature stability if an y separated components will eadily eturn nto olution t he owest n- ticipated operating temperature.

Low-temperature roperties f ydraulic luids become mportant n toring luids n old nvironments or when hydraulic systems are subject to periods

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of nonoperation n old nvironments. Formation of gels, crystals, or separation of components could cause clogging of filters, plugging of small orifices and clearances, or lack of lubrication to vital components.

3-2.14.2 Test Methods fo r Low-temperature Stability

(1 ) iscosity Stability at Low Temperature: Test Method : Federal Test Method 07 Ref. 7) Change in viscosity of fluids subjected to low temper-

atures s often se d as criterion of low-temperature stability. This method describes a procedure for determining he iscosity tability of transparent luids t -65°F. n his ethod, ample of he ubricant s placed in a glass capillary-type viscometer in a bath at -65°F. The kinematic iscosity of the ample s hen determined. The viscometer and the sample are kept in the bath t -65°F for 72 hr and determinations of the kinematic iscosity re made t ntervals hroughout the 72-hr period. Changes in viscosity with time provide a measure of low temperature storage instability.

(2 ) elling, rystallization and Separation: Test Method : Federal Test Method 45 8 Ref. 8) This method is used for determining the tendency of

components of finished oil blends to be incompatible or to form gels during low emperature exposure.

A 00-ml sample of the liquid to be tested is placed in a glass jar and stored for 72 hr at he temperature required by the liquid specification. At the end of the 72-hr period the sample is removed from storage and immediately examined visually for evidence of gelling, separation, or crystallization. If there is an y evidence of gelling, eparation, or crystallization, he iquid s e- ported as unstable at the specified temperature.

(3 ) urbidity: Test Method : Federal Test Method 459 Ref. 9) This method is used for determining the stability at

low emperature of finished liquid blends. An -oz ample of he iquid o e ested nd

250-ml sample of a standard composed of barium chloride, sulfuric acid, sodium hydroxide, and distilled water are stored at the temperature and for the number of hours required by the liquid specification. At the end of the storage period, the standard is shaken vigorously

for 10 sec. The liquid sample is also shaken vigorously for 0 sec. The turbidity of the sample liquid is compared to that of the standard and reported as less than, more than, or equal to the standard. Also reported s any evidence of gelling, crystallization, or solidification of the sample liquid.

3-2.15 SEDIMENTATION

Sediment is anything that settles out of a liquid. n hydraulic fluids and lubricating liquids, he definition of sediment is usually restricted to insoluble products that re present n he iquid ecause of refining or production processes, or because of chemical reactions

that occur n he hydraulic ystem during se . edimentation is usually distinguished from contamination which is an y undesirable matter, oluble or insoluble, that s ntroduced nto the hydraulic luid ecause of improper handling or storage, use of unclean hydraulic systems, eaks n ystems, tc. Contamination s iscussed in Chapter 6. Sedimentation is present-as dust, dirt, metal, nd ust particles icked up rom piping and storage vessels-in most ne w commercial hydraulic fluids as a result ofproduction and refining. Sedimenta- tion in used hydraulic fluids would include these solids as ell s etal wear particles, orrosion roducts, oil oxidation products, or other insoluble oil degrada-

tion products. Sedimentation can become quite critical in hydraulic systems that have close-tolerance moving parts or small orifices. he ediment an ettle n hese reas nd produce a tarnish or sludge which can seriously ham- per the operation of the system. Furthermore, sediment can clog filters and reduce their efficiency. Candidate hydraulic fluids have been known to be rejected, even though they satisfied all specification requirements, be - cause they experienced sufficient chemical changes to produce excessive amounts of sediment.

The procedure for testing for trace sediments in lubricating iquids s iven y ederal est ethod

3004.4 Ref. 0) nd ASTM -2273-64T Ref. 1). These methods describe the procedure for the determination of trace amounts less than 0.05 volume percent of sediment n lubricating liquids. A 0-ml ample of the test liquid is mixed with 50ml of naphtha in a trace sediment ube Fig. -52) nd entrifuged t iven speed or 0 min. he mixture s decanted nd he sediment is left in the tube. Another mixture of 50 mlnaphtha and 50 ml test liquid is mixed in the same tube and again centrifuged for 0 min. The final volume of the sediment is noted and the results are reported as the volume of sediment/100 ml of sample liquid.

Precision : Results should not be considered suspect

unless they differ by more than the following amounts:

Sediment, %

0.000-0.002 0.003-0.005 0.006-0.01

Repeatability

0.001 0.001 0.002

Reproducibility

0.001 0.002 0.003

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f ioo\

185- 1 9 6 mm

50

.01

^

6-7 mm

Fig. 3 - 5 2 . Trace Sediment Test Tube

3-3

UBRICATION ROPERTIES

3-3.1 GENERAL

Varying degrees of lubrication and wear preventing ability are needed fo r different systems. The pump de - sign, the system operating temperatures and pressures, component esign, nd nvironmental onditions should ll e onsidered when electing ydraulic luid.

Two fundamental and distinct modes of lubrication

are generally recognized-hydrodynamic and boundary lubrication. When ydrodynamic onditions xist, liquid film entirely separates the moving parts. n the boundary condition, contact exists between the mating surfaces. he ifference etween ydrodynamic nd boundary ubrication s lear; owever, here s o sharp line of demarcation, but rather a gradual transition etween he two.

3-3.2 HYDRODYNAMIC LUBRICATION

Hydrodynamic lubrication is A system of lubrication n hich he hape nd elative motion f he

sliding urfaces ause he ormation of a iquid ilm having ufficient ressure o eparate he urfaces" (Ref. 92). Under ideal hydrodynamic conditions of lubrication, there is essentially no wear since the moving parts do not touch each other. Under these conditions, the parameters of importance are liquid, viscosity, surface peed, nd pressure.

Most of the heory of hydrodynamic ubrication s based on the early work of Tower and Reynolds. Full hydrodynamic lubrication offers the significant advantage of low wear rates and low friction. Hydraulic systems should be designed to take full advantage of hydrodynamic ubrication. The coefficient of friction n

hydrodynamic ubrication s of the order of 0.001 o 0.010 (Ref. ).

A hydraulic fluid should be a good lubricant so that friction and wear in a hydraulic system are reduced to a minimum. he omponents of a hydraulic ystem contain many surfaces which are in close contact nd which move n uch elation o ach other hat he hydraulic luid must eparate nd ubricate. The y- draulic fluid must also be a good wear preventing lubricant. Wear in hydraulic pumps, cylinders, motor controls, alves, nd ther omponents an esult n increased eakage, oss of pressure, es s ccurate on - trol, or failure. Protection against wear is often a princi- pa l reason for selection of a particular hydraulic fluid since most components of hydraulic systems operate at some im e under conditions hat an ead o extreme wear, specially uring tarting nd topping f the ystem.

3-3.3 TRANSITION R OM HYDRODYNAMIC TO BOUNDARY LUBRICATION

A given liquid film between moving parts decreases in thickness as the pressure increases, and/or the liquid viscosity ecreases. s he ilm ecomes hinner, point is reached where the laws of hydrodynamics no longer fully apply since the effects of surface or boundary forces are no longer negligible. As the film becomes still thinner, a state is ultimately reached where metal- to-metal contact occurs. These transitions influence the coefficient of friction as shown in Fig. -53. Here, the coefficient of friction s plotted s unction of the dimensionless parameter ZN/p where Z, N, and p are the fluid iscosity, elative urface peed, nd ressure, espectively.

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The temperature and pressure at the region of contact are the factors that determine the severity of the boundary ubrication. A ll ypes of boundary ubrication are characterized by the rupture of the liquid film and some degree of metal-to-metal contact. The conditions of boundary lubrication should be avoided where possible because of the resulting increase in power con-

sumption, nd the high friction and wear that occur.

separation of fluid an d water. Some of the more effective EP additives lso av e tendency o eact with certain structural metals or with some of the synthetic hydraulic fluids.

3-3.6 DEFINITION OF TERMS USED IN DESCRIBING LUBRICATING

CHARACTERISTICS

3-3.5 EXTREME PRESSURE LUBRICATION

Extreme boundary lubrication (par. -3.4) in which both emperature and pressure are ery high is often referred to as Extreme Pressure, or EP , lubrication. EP conditions re ound n hydraulic ystems n pumps, motors, and actuators. EP conditions are characterized by welding of portions of mating surfaces, followed by the earing way f elatively arge particles of the metal. A variety of special ubricants with properties

tailored to meet the severity of the particular application can frequently be used when EP conditions exist. These special properties are generally derived from the various additives contained in the fluid (see Chapter 5), and the net effect is to increase the load-carrying ability of the fluid.

Lubrication when EP conditions exist depends upon a combination of mechanical and chemical effects. Part of the lubrication may result from an absorbed film that is present on the tw o surfaces, and part from additives in he iquid hat hemically ttack hese urfaces where-as esult of high pressure nd high liding velocity-exceedingly high temperatures result. The formation of reaction products hen prevents eizure of the moving parts and may reduce friction. The temperature involved may be on the order of 900°F, or higher, so these reactions are often ery apid.

There are various degrees of EP conditions and various ypes of EP additives o meet hem. The type of additive selected for an y particular application will de - pend on the severity ofthe boundary conditions. Differ- ent ypes of additives re se d or high emperature boundary conditions than for high pressure boundary conditions. A more omplete discussion of boundary condition dditives s n hapter . ecause of the range of conditions through which a system may oper-

ate, t s requently ecessary o nclude more than a single additive, on e for the more severe conditions and another or he ess evere onditions. Certain disadvantages may result from the use ofEP additives. Some additives may increase the emulsifiability of the fluid, making it undesirable fo r applications requiring rapid.

The more common terms used to define the lubricating bility of a iquid re ilm trength, iliness, nd lubricity. These terms are not precise and a standard of definitions f ubrication, riction, nd ear erms recommends hat hey o onger e se d Ref. 2). However, the terms have been used for many years and do ppear n most of the iterature pertaining o u- bricating characteristics of liquids.

3-3.6.1 Film Strength

Film trength s The bility of a urface ilm o resist upture y he penetration of asperities during sliding or rolling" (Ref. 92). n general, the higher the viscosity, he higher he ilm trength. igh ilm strength is primarily inferred from a high load-carrying capacity and is seldom directly measured. It is possible to ncrease he ilm trength f iquid y se of additives.

3-3.6.2 Oiliness

Oiliness is the property of a liquid which causes films of two liquids of identical viscosity to exhibit different coefficients f riction. iliness s ssociated ith boundary ubrication nd he ntermediate one e- tween boundary nd hydrodynamic ubrication. he oiliness of a liquid can be increased by the use of additives. These additives are usually oils of animal or vege- table origin nd av e certain polar characteristics. A polar molecule has a strong affinity fo r the metal surface with which it comes in contact and fo r like molecules. uch a molecule is not easily dislodged from its attachment to the surface. For moderate boundary conditions, damage of sliding parts can e effectively e- duced by he use of oiliness agents.

3-3.6.3 Lubricity

Lubricity s he bility of iquid o mpart ow friction under boundary conditions. A fluid that forms

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a ilm of low hear strength s aid o have oo d u- bricity. Lubricity is a complex function which depends upon liquid oiliness, the extreme pressure and antiwear properties of the liquid, and the properties of the rubbing surfaces.

3-3.7 PREVENTION OF WEAR

The complete elimination of wear is practically im - possible. inimum wear occurs under onditions of hydrodynamic lubrication and maximum wear occurs under onditions of boundary ubrication. owever, there re everal pproaches y which he wear ate under boundary lubrication conditions can be reduced to a satisfactory or controllable level. The main factors which determine the rate of wear can be classified into two asic ypes-mechanical nd ubrication. roper consideration of these tw o factors can produce a wear rate which s acceptable.

3-3.7.1 Mechanical actors

The mechanical factors that affect the wear rate are the choice of materials, the surface finish, and the operating conditions.

Wear an ften e educed y proper hoice of materials or he oving arts. n eneral, ofter materials ear ore apidly han arder materials. There is, however, no direct relationship between hardness nd esistance o wear. aterials lso iffer n their bility o esist he various ypes of wear. or example, materials elected or heir bility o esist abrasion might be more sensitive to corrosion. It is thus necessary o elect materials which would esist he most serious type of wear anticipated.

The combination of metals used can greatly influence the wear. om e metals re ery usceptible o wear when rubbed against themselves, while others are very susceptible to wear when rubbed against different types of metals. n practice, he omposition hosen or given part s nfluenced y many actors other han wear. Structural strength, weight, cost, and availability may force a compromise between minimum wear and optimum performance.

Surface finish of the mating parts becomes particularly important during break-in or initial wear periods. If on e of the two mating surfaces has an initial rough finish, onsiderable wear may ake lace. While t s generally desirable to have as smooth a surface as possible, here re nstances where urfaces of controlled roughness are desired so that a "wearing-in" or mating

of parts may occur during the initial un-in or break- in eriod.

Operating onditions of pressure, emperature, nd rubbing speed also affect wear. Increased pressure generally reduces film thickness and increases the extent of metal-to-metal ontact nd ear. igh emperature may cause wear du e to a decrease in viscosity. Exces- sive igh peeds ay esult n verheating t ocal points. oderate emperatures nd ressures re , therefore, preferred rom standpoint of wear. How- ever, ptimum onditions or wear may ot e he optimum conditions to achieve high efficiency or maximum ower from hydraulic system component.

3-3.7.2 Lubrication Factors

Decreases n iscosity of a ystem operating under hydrodynamic ubrication will ecrease he hickness of the liquid film. f the decrease is sufficient to allow boundary conditions to be reached, metal-to-metal contact ccurs nd wear ncreases. iscosity, herefore, would be expected to have an inverse effect on rate of wear-the greater he iscosity he ess would e he expected wear.

Since ear s ssentially henomenon esulting from riction, t s xpected hat dditives apable of reducing riction nder oundary onditions ould simultaneously educe wear. owever, here an e instances where there is little or no correlation between friction nd wear under boundary ubrication onditions (Ref. 3). Some additives effective in reducing friction av e ittle effect upon wear, while others educe wear and have little effect upon friction. Lack of correlation is probably du e to the fact that wear takes place momentarily in isolated spots whereas friction is normally measured as an average for a larger area and a longer time interval (Ref. ).

Hydraulic components made from iron alloys other than tainless teel re ubject o orrosion nless proper precautions are taken. Most mineral-oil liquids do not have good antirust properties. Although they do offer protection, they must be fortified with appropriate additives if an y marked degree of rust prevention has to be achieved Ref. ).

3-3.8 TEST METHODS FOR LUBRICATING PROPERTIES

Numerous test methods have been proposed and several av e been dopted or valuating he ubricating and wear reducing properties of fluids. The majority of

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these tests have been developed for materials other than hydraulic luids uch s ubricants, reases, nd, n some ases, olid ubricants. owever, he asic est procedures are adaptable to the evaluation of hydraulic fluids, and several Military Specifications for hydraulic fluids call for these tests or some modification of them.

The test methods fall into three general categories-

bench-type ests sing onsimulating est lements, simulated hydraulic ystems, nd he more laborate load-carrying nd cuffing ests. Standard est procedures, either ASTM or Federal, have been written for some of the test methods.

None ofthe test methods described in the paragraphs which follow give an y indications of the expected "life" of a ubricant or iquid. The ngineer or designer s expected to establish proper lubrication procedures and lubricant change intervals. The problems become even more complicated in hydraulic systems because the liquid is both a lubricant and a power transfer fluid. With hydraulic systems operating with sophisticated hydrau-

lic fluids and/or extreme operating conditions, alling back on "accepted practice" can be expensive, either in terms of wasted hydraulic fluids or damaged equipment.

3-3.8.1 Bench-type Friction an d Wear Testers

Several bench tests have been developed to measure the lubricating ability of liquids. Each test employs a different type of apparatus that utilizes a unique combination of test elements. The testers are similar in that two well-defined surfaces separated by a liquid film are in motion with respect to each other. The coefficient of friction s sually etermined y easuring he e- straining orce n ne of the est lements. Wear s determined by the loss in weight of the parts or by the dimensions f he ear car. oundary ubrication characteristics re determined y ncreasing he oad on he surfaces until seizure occurs.

Because of their differences, the various bench testers do not ecessarily rate a given series of liquids in the same order, and results from a single test procedure can be misleading. Also, the results obtained do not always correlate well with actual operation. In many instances, the results of several different bench tests may be taken as a whole n determining he lubricating ability of a given hydraulic luid. Experience has hown hat p- plication of most of these test procedures will separate those hydraulic fluids which are extremely poor lubricants from those which are potentially good lubricants.

Five of the more commonly used bench-type testers and their test methods are described in the paragraphs which ollow.

3-3.8.1.1 Timken Tester

Test Method : Federal Test Method 505 Ref. 3) In the Timken test, a steel block is pressed against a

rotating, ylindrical steel ring (see Fig. -54(A)). The test is run for 0 min at a rubbing speed of 400 ft/sec. The iquid s llowed o low ver he est ieces. n

starting a test, the motor is brought up to speed and a load is placed on the steel rub shoe block by means of a weight and lever system. The test can be conducted as a wear test by running at a se t load until failure or as an EP - or load-carrying test by increasing the load until failure. Federal Test Method 6505 (Ref. 93) calls for he est o e onducted s oad-carrying est. Failure is indicated by scoring on the test block or test ring. The results are reported as the load (determined from he car dimensions nd. the oad) pplied just prior to scoring or pickup of metal.

3-3.8.1.2 Almen Tester

In he Almen est, cylindrical od is otated n split bushing which s ressed gainst t see ig . - 54(B)). Frictional orce s measured y estraining force on the split bushing. Two versions of the Almen test are conducted-the Almen EP test and the Almen wear test.

In the Almen EP test, the machine is run without an applied load fo r 30 sec asa break-in period. Weights are added very 0 ec n multiples of 2 b until ailure occurs s ndicated y eizure or udden ncrease n torque. est esults re xpressed s he orque nd load which causes seizure.

In the Almen wear test, the machine is run without an pplied load or 0 se c as break-in period. Four 2-lb weights are added at 0-sec intervals. Operation is continued for 20 min. Total weight loss of the journal and the bushings in mg is determined, and is reported as he wear.

3-3.8.1.3 Falex Tester

Test Methods : Federal Test Method 3807 (Ref. 4) Federal Test Method 81 2 Ref. 5)

In the Falex test a cylindrical rod is rotated between tw o hard V-shaped bearing blocks which re pressed against he od see ig . -54(C)). riction orque s continuously monitored. Both he journal nd he V blocks are submerged in the liquid under test. The tw o Federal est ethods eferenced bove tilize he Falex Tester in the evaluation of solid film lubricants.

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(A) Timken (C) Falex

<=3

(D ) Four-Ball (E) SA E

Fig. 3 - 5 4 . Five Bench-type Friction an d Wear Testers

However, he asic rocedures f he wo ests re adaptable to the evaluation of liquids. The test can be run in tw o ways-as a wear test and a load carrying test.

For wear testing, he machine is un t .a pecified load for a specified time. The amount of wear is determined as the amount of adjustment that must be made in he loading system o maintain the desired load.

For the EP test, he load is increased continuously until eizure occurs. The est egins with break-in period or min t 00 b oad. The oad s hen n- creased to 500 lb and held for min and then increased in 50-lb ncrements with -min un until ailure occurs. Results are expressed in pounds load at seizure.

3-3.8.1.4 Four-ball Tester

Test Methods : ASTM D-2596-67T (Ref. 6) Federal Test Method 6514 (Ref. 7) ASTM D-2266-64T (Ref. 8)

In he our-ball machine often alled he Shell"

Four-ball Tester) a 1/2-in.-diameter steel ball is rotated in contact with three stationary similar balls which are clamped n ixed osition see ig . -54(D)). he rubbing urfaces re ubmerged n he iquid o e tested. The test can be operated s wear est or n £Ptest.

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For a wear test, the machine is operated at a specified temperature, oad, nd peed, ith alls f iven material. ederal est ethod 51 4 Ref. 7) nd ASTM D-2226-64T (Ref. 98 ) are used for determining the wear characteristics of lubricating greases with the four-ball tester. The general procedures are adaptable to hydraulic fluids as well as greases. They call for test

conditions of 1,200 rpm, a load of 40 kg, a test temperature of 167°F (75°C), and a test time of 60 min. At the end of the est, he car diameter on he ower hree balls s easured nder icroscope. he verage diameter in millimeters is reported and is a measure of wear under the specified conditions.

For the EPtest (ASTM D-2596-67T (Ref. 96)) there is no provision for temperature control, and the test is started at room temperature. A test run of 10-sec duration at a given load is usually made. Scar diameters are measured nd he Hertzian ontact tresses re alculated. The load s ncreased n ncrements, nd he process s epeated until welding occurs. This oad s called he weld point or weld oad.

Many variations on the four-ball wear and EP tests are used. Many liquid specifications call for a four-ball test as specified or with certain changes made in the test time, oad, peed, or temperature.

3-3.8.1.5 SAE Tester

Test Method: Federal Test Method 50 1 Ref. 9) In the SAE machine (see Fig. 3-54(E)), tw o cylinders

aligned xially nd n ontact ith ach ther re

driven at different speeds. One of the cylinders may be driven in either direction. The pieces evolve under a flooded lubrication condition from the test liquid held in a cup. The load pressing the cylinders together can be increased until failure occurs. This machine differs from the four-ball tester in that a combination of rolling and sliding friction is involved. The ratio of sliding to rolling can be changed by varying the relative speed of the tw o cylinders.

Federal Test Method 6501 Ref. 9) is a test procedure for determining the load-carrying capacity of gear lubricants using the SAE tester. The same test rocedures, however, are adaptable to an y liquid lubricant or

to hydraulic luids. The machine s tarted nd pe - rated at a light load for a 30-sec break-in period. The automatic oading evice hen ncreases he oad steadily until scoring occurs. The results are expressed in erms of the verage oad needed o ause coring based on three repeat ests.

3-3.8.2 Evaluation of Lubricating Properties by Pump Tests

None of the bench tests gives accurate or complete correlation with the operation of hydraulic fluids in a hydraulic system. The final test of the lubricating characteristics of an y hydraulic fluid is its actual perform-

ance n hydraulic ystem. The hydraulic pump s usually the most critical unit as fa r as lubricating characteristics of the hydraulic system are concerned; therefore, pump ests av e been developed nd widely c- cepted fo r tudying ubricating properties of hydraulic fluids.

Pump tests normally involve the simplest hydraulic circuit possible: a pump; a means of maintaining system pressure such as relief valve; reservoir; heat x- changer; and various instruments for measuring speed, pressure, temperature, and flow rate. The test is usually run for a specified period of time with a given pump. Critical parts of the pump re xamined efore nd

after esting, nd he mount of wear determined y changes in dimension or changes in weight. In addition to data on he lubricating properties of

hydraulic fluids, pump tests provide data on the overall performance of the pump system, nd he unctional ability f he hydraulic luid. ther enefits ained include: ctual determination of wear n imulated system; information on liquid stability; effects of seals and ackings, orrosion, ludging; nd he heat nd power transfer qualities of the liquid under controlled conditions (Ref. ).

Several pump tests have been described in the literature. A ll types ofpumps have been used, and test conditions

have been widely

varied.

om e pump

tests have

been eveloped pecifically or shear stability valuation (see par. 3-2.5.3), but will still provide data on the lubricating properties of the liquid. A few of the pump tests have been written into formal test procedures and are discussed in the paragraphs which ollow.

3-3.8.2.1 Simulative Recirculating Pump Test

Test Method : ASTM D-2428-66T (Ref. 00 ) This est ethod overs rocedure or ystem

evaluation of aerospace hydraulic fluids. The method recommends a typical test system geometry, data to be

obtained, and control of test variables and procedures to ssure a uniform pproach of liquid creening and evaluation. ecommendations oncerning pecific hardware nd igid echniques ave een voided where possible to allow the general method to be used as the state-of-the-art advances. Since the method was

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purposely eneralized, t s mportant hat pecified data be aken n order that alid comparisons of test results of various liquid can be made. The method consists of recirculative pumping of the test liquid through a ystem hat losely imulates he inal ystem n which he iquid will e sed. Wear nd ubricating properties of the liquid are determined from evaluation of critical parts of the system before and after the test. This test procedure, however, is not primarily intended for wear and ubrication esting, but ather for liquid functional uitability.

3-3.8.2.2 Pump Loop ea r Test

Test Method : ASTM D-2271-66 Ref. 01 ) This test method describes a procedure for measur-

ing the wear characteristics of hydraulic fluids for use in ndustrial pplications. A ixed volume of the y- draulic luid s irculated hrough pump ig under standard conditions of time, pressure, and temperature for ,000 hours. ifferences n weight of he pump parts t he tart nd inish of the est re eported along with the total percent oss.

3-3.8.3 Other Lubricating Characteristics Tests

Numerous other tests for evaluating the lubricating properties of lubricants have been developed. Several of the procedures hat oncentrate n he oad-carrying ability of iquids av e een ritten nto ormal est procedures. These test standards are not primarily intended for the evaluation of hydraulic fluids, but men- tion of them is made here since they have been used to screen potential hydraulic fluids. They are now being used ore requently, nd he rend oward ore severe operating conditions in aircraft often leads to the use of the same liquid as lubricant and hydraulic fluid. The ubricating properties of the iquid hen ecome extremely mportant.

3-3.8.3.1 Load-carrying Ability of Lubricating Oils at 40CTF

Test Method : Federal Test Method 6511 Ref. 02 ) This method describes a procedure for determining

the oad-carrying bility of lubricating ils t 00°F with espect o gears.

Two pecial est ears re mounted n WADD High-temperature Gear Machine adapted to a modified

Ryder Gear-Erdco Universal Drive ystem. The est oil s heated o 400°F an d he gears rotated t 0,000 rpm in cycles of 10 min with uniform increases in gear load for each cycle. The gears are examined for scuffing at the end of each cycle. The cycles are continued until a se t percentage of gear tooth face scuffing is observed. The load-carrying ability is that gear tooth load which produces an average gear tooth scuffing of 22.5 percent. Results re eported s he percent of load-carrying capacity of the est il to a reference oil.

3-3.8.3.2 Load-carrying Capacity of Steam urbine Oils

Test Method : ASTM D-1947-66 Ref. 03 ) This test method is almost the same as he on e de -

scribed n ar. -3.8.3.1. The exceptions are that t s limited to steam-turbine oils and is conducted without heating the test iquid.

3-3.8.3.3 Gear Fatigue Characteristics of Aircraft Ga s Turbine Lubricants at 40(fF

Test Method : Federal Test Method 6509 (Ref. 04) This method describes a procedure for determining

the fatigue characteristics of aircraft ga s turbine engine lubricants at 400°F with espect o ears.

Two pecial est ears re mounted n WADD High-temperature Gear Machine adapted to a modified Ryder Gear-Erdco Universal Drive ystem. The est oil s heated to 400°F and he gears otated at 0,000 rpm in 0 min cycles with uniform increases in load at each cycle. At the end of each cycle the gears are examined or cuffing. When redetermined aximum load is reached, the cycle duration is increased to 2 hr at constant load. At the end of each cycle, the gears are then observed for development of fatigue pits which are large enough to be readily discernible to the eye.

Results are reported as the percent of load-carrying ability, with respect to a reference oil, of the test oil and the rating of each fatigue cycle in terms of the number of fatigue its.

3-3.8.3.4 Load-carrying Ability of Lubricating Oils

(Ryder Gear Machine)

Test Method : Federal Test Method 6508 (Ref. 05) This method describes a procedure for determining

the load-carrying ability of lubricating oils with respectto gears.

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Two special test gears are mounted in a Ryder Gear- Erdco niversal ester. he est il s eated o 165T and the gears rotated at 0,000 rpm in cycles of 10 min ac h with uniform ncreases n gear oad or each cycle. The gears are examined for scuffing at the end of ac h ycle. The ycles re ontinued until preset percent of gear tooth cuffing is observed. The

load-carrying ability is that gear tooth load which produces n verage ear ooth cuffing of 22.5 percent. Results re eported s he percent of oad-carrying ability of the test il o a eference il.

Precision : (a ) epeatability. elative eadings hould ot

differ from heir mean y more han 0 ercent.

(b) eproducibility. Relative readings should not differ from their mean by more than 5 percent.

3-4 CHEMICAL PROPERTIES

3-4.1 CHEMICAL STABILITY

Most hydraulic luids re omplex mixtures which are affected by temperature, pressure, atmospheric conditions, moisture, metals in the hydraulic system, mechanical hear, nd ther xternal nfluences. hese influences efine he operating onditions of the y- draulic system, nd a hydraulic fluid should be stable under the imposed conditions. Any or all of these influences can change the properties of the hydraulic fluid to such an extent that t may be unsuitable fo r use in the ystem or which t was ntended. However, t s mandatory that the system be operated with a hydraulic luid hat oe s ot uffer egradation r hat changes only to such an extent that its operating ability is not significantly impaired within a defined range of use conditions.

The stability of many ypes of hydraulic luids as been extensively studied under a wide variety of conditions n the laboratory. Oxidation, hermal stress, hy - drolysis, radiation, and mechanical stress due to shear and cavitation are the primary forces that tend to alter the chemical nature of hydraulic fluids. Stresses due to shear are discussed in par. 3-2.5. Cavitation is discussed in ar . -6.1.2.

Because of the wide variety of fluid tability data available in the literature, examples of specific hydraulic luids will e voided n his iscussion. nstead, relative comparisons will be made of the various chemical lasses of hydraulic luids urrently vailable or under development. For additional details, the specific references hould e consulted.

One of the most difficult aspects of determining stability nvolves he election of criteria of change. A ll hydraulic fluids ca n and will undergo changes in their properties during use. Some of these changes affect the functional ability of the fluid; some affect the chemical composition; om e ffect he hermal properties; tc. Some changes may be harmful while others may have

no effect on the performance of the hydraulic fluid. For example, hanges n olor ndicate hange n he liquid; however, such a change will not normally affect the functional ability of the liquid. On the other hand, an increase in acid content might result in a hydraulic fluid too corrosive for further use, or the viscosity may change so that the hydraulic fluid no longer performs its unction. bviously hen, om e roperties av e much more meaning in terms of hydraulic fluid stability than others. Even then, the conditions to which the hydraulic fluid willbe subjected determine which properties re he ritical ne s nd re most desirable o maintain as stable as possible.

If a liquid encounters on e or more of the stresses or forces reviously mentioned, he esult s enerally change in on e or more of the following: viscosity, formation of volatile components, ormation of insoluble materials, or formation of corrosive products. nsolubles formed may range in nature from hard particles to sludges an d gums. Corrosion products generally formas the result of thermal or oxidative decomposition, or from hydrolysis. Volatile components can form as the result of oxidative, thermal, or radiation effects. A ll of these changes are usually undesirable, and precautions should be taken to avoid them or reduce their effects.

The stability of a hydraulic fluid is also affected y

the metals used in the system. Depending on the chemical type of the liquid, certain metals can act as catalysts in the deterioration process. The problem is essentially a question of compatibility of the hydraulic luid and the metals of construction see ar. -6.1).

3-4.2 OXIDATION STABILITY

Oxidation stability refers to the ability of a liquid to resist reaction with oxygen or oxygen-containing compounds, and is an important factor that affects storage life of hydraulic fluids and performance life of hydraulic fluids used in open systems (noninerted). Oxidation results n iquid eterioration nd s anifested y changes n certain hysical nd chemical haracteristics of the lubricant-such as viscosity, precipitation of insolubles, lacquer and varnish formation, acidity, and corrosiveness. When he oncentration f oxidation products eaches a critical alue, depending upon he

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application, the hydraulic fluid will no longer perform satisfactorily. any f he newer hydraulic ystems reduce he damage rom oxidation y sing ystems that re inerted.

Oxidation rates of most types of liquids are temperature sensitive. Degradation products increase with n- creasing emperature nd , s esult, equire ore

frequent hydraulic luid eplacements. The oxidation rate s lso sually ncreased ith ncreases n he amount of air and water contamination; nd the presence of metallic particles, dirt, nd dust. n ddition, fo r petroleum liquids the type of crude oil from which the liquid s derived, s well s the efining methods, may also affect the oxidation rate.

The oxygen necessary fo r the oxidation reaction usually esults rom he presence of air contamination in the liquid or exposure to air in open systems. n order to retain useful hydraulic fluid ife at higher temperatures, systems must exclude air, and the hydraulic fluid

must e ubstantially ree f issolved ir rior o charging the system. The use of antioxidants can sub- stantially mprove he oxidation tability of a iquid. Practically ll ommerical hydraulic luids are stabilized by antioxidants.

Thermal and/or oxidative stability are generally the factors hat imit he upper operating emperature of the hydraulic luids, epending upon he ystems n which he hydraulic luids re sed. Most petroleum base hydraulic luids re imited o ess han 00°F operation n pen ystems while om e re apable of 550°F operation n losed nerted ystems. The maximum useful temperatures and the oxidation resistance of several types of hydraulic fluids are given in Tables 3- 7 and 3-8. The oxidation resistance ratings shown in Table -8 re or operation elow he ecommended long duration operating temperatures of Table 3-7. The polyphenyl ethers and the silicones are the most stable liquids t he igher emperatures. owever, os t types of liquids are relatively poor lubricants n om - parison with petroleum-base liquids.

Oxidation stability is an important factor in the prediction of the performance of a hydraulic luid n n oxidizing nvironment. Without dequate xidation stability, he life of a liquid may be extremely imited and nless the liquid is frequently replaced, here is a serious possibility of damage to lubricated parts. Oxi- dation tability ecomes prime equisite of iquids serving in closed uninerted lubrication systems such as hydraulic systems where the oil is recirculated fo r ex - tended eriods. There are om e nstances where on -

trolled amounts of oxidation are beneficial. For example, n ertain etals, he resence f xide ilms determines the ability of the metal to be lubricated and prevent surface welding and galling. Complete removal of oxygen rom ystems ontaining uch metals may cause problems when the oxide surface films revert to bare metals (Ref. 06). This possibility is usually taken care of by use of additives such as tricresyl phosphate.

3-4.3 THERMAL STABILITY

Thermal tability s he bility of a iquid o esist decomposition by temperature only. t determines the ultimate emperature imit of service or hydraulic fluid. A s design temperatures of ne w hydraulic equipment continue to rise, the thermal stability of lubricants and hydraulic luids becomes ncreasingly mportant. Much research in recent years ha s resulted in a number of andidate hydraulic luids which an perate or long periods at relatively high temperatures. Sustained high emperature tability f ydraulic luid s

necessary haracteristic. deally, ydraulic luid should not degrade ignificantly etween normal ys- te m verhauls.

Table 3- 9 presents the deterioration temperatures for the same fluids discussed in par. 3-4.2. The polyphenyl ethers an d the silicones have high deterioration temperatures (in excess of 600T). However, the super refined mineral oils and synthetic hydrocarbons have deterioration temperatures almost as high and are better lubricants. The data presented in Table 3- 9 are approximate only and vary depending on the conditions the tests are conducted under. For example, many nonhydrocarbon liquids are less stable in the presence of ferrous metals than other metals.

Measurement of thermal stability has not previously been standardized, but the usual procedure was to relate it to change in weight of the liquid sample, development of acidity, formation of insolubles, or changes in other properties uch s olor, iscosity, pour point, flash and fire points, etc. (Ref. 06). ASTM D-2160-66 (see ar . -4.6.3.2) s ow eing se d commonly s standard test method fo r thermal stability of hydraulic fluids. Various other laboratory nd bench cale tests have been developed, which usually involve heating the liquid and measuring changes in the properties. f the container holding the liquid is open to the air, the test then ecomes ombination xidation nd hermal stability test. In order to separate thermal and oxidative effects, test procedures have been devised in which oxy- ge n s emoved rom he ystem nd eplaced y n inert gas such as nitrogen or helium. These purely thermal stability tests are carried out in sealed systems. The

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TABLE 3-7 .

MAXIMUM O PE RAT I N G T E M PE RAT U RE O F HYDRAULIC FLUIDS

Hydraulic Fluid Type Approx imate Upper U se Limit, F

Long Duration (500-1000 hr)

Moderate Duration (10-100 hr)

H ot Spot Short Duration (< 1 hr)

Mineral Oils Emulsions

Water-glycols

Alkyl Phosphates

Super-refined Mineral Oils, Synthetic Hydrocarbons

Silanes Polyglycols

Dibasic Acid Esters Neopentyl-polyol Esters Silicate Esters Aromatic Phosphate Esters Halogenated Aromatics

Silicones

Polyphenyl Ethers Fluorinated Alkyl Ethers

275

200

225 b

300-450&

325-350 350 375

375-400 200 450

425-550C 500 500

300

550

375-400 400

425 475-525

400

575 550-625 600-700

600

350

700

450-500 42 5 550 575 575 600

800 900

80 0

a Temperature limits depend on the type of pump used such as gear, vane, piston, etc. b Depending on oxidation resistance c Range du e to many viscosities available ~ ~ o reliable data

liquid and container are placed in a chamber which is evacuated and then filled, using nitrogen or other inert gas. This procedure is repeated until little, if any, oxy- ge n remains in contact with or is dissolved in the test liquid. Containers are then heated for a given period of time and he change in he liquid measured.

It s est o determine he hermal tability n n operating system similar to that for which the hydraulic fluid is intended. Pump-loop tests have been devised which can be operated fo r extended periods at elevated temperatures, but they are often impractical because of size and expense. The sealed bomb tests are then often used because test conditions of interest nearly duplicate those n hydraulic systems.

3-4.4 HYDROLYTIC STABILITY Hydrolytic stability refers to the ability of hydraulic

fluids to resist reaction with water. Undesirable forma-

tions of solids or cidic nd orrosive materials may result, or table water nd il mulsion which e- grades ubricating bility nd romotes usting nd corrosion may orm.

Since it is rarely possible to completely exclude moisture from an y lubricant or hydraulic system, hydrolytic stability is an important requirement of fluids. It affects the life of liquids both in the original storage containers and in the hydraulic system. In storage, moisture may come in contact with a hydraulic fluid if storage drums are no t properly sealed. Within the hydraulic system, temperature changes will cause reservoir breathing and condensation of moisture during hut-down eriods. Even in supposedly sealed" ystems, moisture is difficult o xclude ecause of seals, ittings, nd other possible leakage oints.

Until the advent of synthetic liquids, little consideration was iven o hydrolytic tability ecause of the

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TABLE 3-8 .

OXIDATION A ND VARNISHING RESISTANCE O F HYDRAULIC FLUIDS

Hydraulic Fluid Type Resistance to

Oxidation Tendency to Form Solids or Varnish

Mineral Oils

Good Water-in-mineral Oil Emulsions Good —

Water-glycols Good —

Alkyl Phosphates Good —

Super Refined M ineral Oils, Synthetic Hydrocarbons, and Silanes Fair to good Large

Polyglycols Fair Small to medium Dibasic Acid Esters Good Large Neopentyl-polyol Esters Good Large Silicate Esters Fair to good Small to medium Aromatic Phosphate Esters Good

Medium Halogenated Aromatics Excellent to 500°F Small Silicones Excellent to 400°F

Good above 400°F Small Small

Polyphenyl Ethers Excellent to 500°F Small

No reliable data

[From: F. D.Yeaple, Hydraulic and Pneumatic Power and Control 5 8 . se d by permission of McGraw-Hill, Inc.]

outstanding ydrolytic tability f etroleum ils. However, stability of synthetic fluids and of some addi-

tives n hydraulic luid ormulations must e onsidered. able -10 resents ata n he elative y- drolytic stability of several classes of hydraulic fluids. The most moisture-sensitive of these hydraulic luids are he ilicate sters. Hydrolysis of these luids produces a silicate sludge which readily clogs filters, servo valves, and capillary passages. Great care is needed to insure that o water is present n he system prior to charging with his type of fluid.

3-4.5 RADIATION ESISTANCE

It has only been since the early 1950's that the radiation esistance of hydraulic luids as ecome important. In the design of modern weapon systems, aircraft, and echanical evices, ydraulic ystems re re - quently expected to be exposed to nuclear radiation. Of all system components, the hydraulic fluid is the most

susceptible to damage by radiation. ince convention- ally used hydraulic fluids and lubricants are especially susceptible, he effects of radiation n heir performance should be considered in the design of almost ll systems. However, there is no general requirement fo r radiation esistance in most hydraulic fluid specifications.

Considerable basic work has been done on the radiation of simple organic structures. With the more complicated olecular tructures haracteristic of lubricants, both petroleum nd ynthetic, t has not een feasible o make tudies of the recise eactions hat occur. The mpirical observations re: (Ref. 07) a) viscosity may at irst e decreased, but ventually n- creases, (b) acidity increases, (c) volatility increases, (d)

foaming tendencies increase, (e) coking tendencies generally ncrease ut ccasionally ecrease, f) lash points decrease, (g) autogeneous ignition temperatures decrease, nd h) oxidation tability decreases.

In ddition o he isted hanges n hysical nd chemical properties, gas is always liberated (Ref. 07).

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TA BL E 3-9.

D ETER I O R ATI O N T E M P E R AT U R E OF HYDRAULIC FLUIDS

TA BL E 3-10.

H Y D RO LY T I C STABILITY O F HYDRAULIC FLUIDS

Hydraulic Fluid Type Incipient Thermal

Degradation

Temperature °F

Super-refined M ineral Oils, Synthetic Hydrocarbons, an d Silanes 600-700

Polyglycols 500-550

Dibasic Acid Esters 525 Neopentyl-polyol Esters 575

Silicate Esters 550-600 Aromatic Phosphate Esters 500-600

Halogenated Aromatics 600-650

Silicones 625-800 Polyphenyl Ethers 750-850

[From: . D. Yeaple, Hydraulic and Pneumatic Power and ontrol sed y ermission f McGraw-Hill, Inc.]

For petroleum liquids the gases are frequently hydro- ge n and methane. The remaining products of decomposition re requently els hat end o log hydraulic systems. The formation of the gases and gels presents a ifficult esign roblem, nd rovisions ust e made in he system or their presence.

Although om e hanges n ubricants ave een found after radiation doses of 107r oentgens, 2 the major effects re bserved etween 08 nd 09 oentgens (Refs. 07, 08). Beyond 0 oentgens most liquid lubricants have been damaged to the extent that they are completely unserviceable.

In eneral, petroleum lubricants are more resistant to radiation damage than other lubricants. An excep- tion is the polyphenyl ether family which is very resistant o amage. Currently, he silicone iquids exhibit the poorest radiation resistance of all the high temperature iquids Ref. ). nclusion of atoms other han carbon, hydrogen, and oxygen in the molecule generally educes adiation esistance. Table -1 1 resents data on the relative radiation resistance of various hydraulic fluids. 2

1 oentgen = bsorption of 93 ergs/g water or 83 ergs/g air. 1rad = 00 rgs/g.

Hydraulic Fluid Type Comparative Rating

Super-refined Mineral Oils, Synthetic Hydrocarbons, an d Silanes Excellent

Polyglycols Good

Dibasic Acid Esters Fair Neopentyl-polyol Esters Fair Silicate Esters Poor to Fair Aromatic Phosphate Esters Fair to Good Halogenated Aromatics Excellent

Silicones Excellent

Polyphenyl Ethers Excellent

[From: . D. Yeaple, Hydraulic and Pneumatic Power an d ontrol 55 . se d y ermission f McGraw-Hill, Inc.]

Considerable work has been done on the repression of radiation damage o organic iquids y dditives. The resence f dditives uc h s ntioxidants nd foam nhibitors may ffer light epression of he effects of radiation.

3-4.6 CHEMICAL STABILITY TESTS

A arge number of tests o determine he chemical stability of hydraulic luids have een proposed nd developed. Their number and variety are almost over- whelming. om e tests are comprehensive in hat hey evaluate the overall stability of the liquid over a wide range of conditions. Others re ery narrow n heir scope in that they evaluate the stability of on e property of the liquid over a more limited range of conditions. All of the ests, owever, re of tw o asic modes of operation: (1 ) tests which measure changes in selected properties of the iquid efore nd fter xposure o controlled conditions, and (2 ) tests which measure the effects of the liquid on a controlled system component or test specimen. Examples of the latter type are pump- loop ests which measure he ffect of liquids n he pump, and oxidation-corrosion tests which measure the changes in metals exposed to the liquids.

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TA BL E 3-11.

RADIATION RE SI STA N CE O F H Y D R A U LI C FLUIDS

Fluid Type Relative

Radiation Resistance

Mineral Oüs: MIL-H-5606 Poor MIL-L-25598 Low

Super-refined M ineral Oils: Naphthenic an d Paraffmic Poor

Synthetic Hydrocarbons (Average) Poor

Diesters: MIL-L-7808C Poor

Triesters: IL-L-9236B Poor

Silicate Esters Poor Disiloxane-diesters: MLO-8515 Poor

Disiloxane: MLO-8200 Poor

Polysiloxanes Poor Chlorinated Silicones Poor

Silicone Ester Blends: MLO-5998 Poor

Phosphate Esters Poor

Polyphenyl Ethers Excellent

[From: . par, Hydraulic Fluids and heir Applica- tions^6 0 . Used by permission of ASME.]

Since there is a wide variety of tests, only a few of the more idely ccepted rocedures ill e iscussed here. These tests can be divided into five areas of ap - plication: general ndicators of liquid tability, xidation tability ests, hermal tability ests, hydrolytic stability tests, and radiation resistance tests. The inclusion of a test in on e particular category does not mean it s imited ntirely o hat ategory-only hat ts predominant se is n hat eneral area.

3-4.6.1 Indicators of Liquid Stability

A large number of the tests for liquid stability consist of determining the values of various properties of the liquid, ubjecting he iquid o ontrolled est ondi-

tions, nd hen measuring the changes in the selected properties. Those properties most often used as indicators of changes in liquid stability are: color, iscosity, flash nd ire oints, eutralization umber, arbon residue, recipitation number, nd sh ontent. he viscosity nd he neutralization number are he most

commonly used indicators. Viscosity test methods have been described n ar . -2.1.11. Flash nd ire points have been discussed in par. 3-2.7.1.1. Details of the test methods fo r precipitation number and ash content can be found in the ASTM Test Methods (Refs. 09, 10).

3-4.6.1.1 Color

Test Methods : Federal Test Method 102.6 (Ref. 11) ASTM D-1500-64 (Ref. 12)

This ethod escribes procedure or he isual determination f he olor of ide ariety f e- troleum products such as lubricating oils, heating oils, diesel fuel oils, nd petroleum waxes. While the color of a hydraulic luid may av e o correlation with ts functional ability, a change in color generally does indicate a change in the fluid and can be used as an indicator of possible stability changes.

A measured ample of the est luid diluted with kerosene when samples are darker than ASTM Color No. ) s placed n tandard lass ample jar n colorimeter, nd its color is compared to the color of standard lass anels. The olor of the ample s e- ported as the number of the ex t darkest glass standard.

Precision: The data which follow should be used fo r judging the acceptability of results. Results should not be considered suspect unless they differ by more than the following amounts:

(a) epeatability. .5 olor unit (b) eproducibility. .5 olor unit

3-4.6.1.2 Neutralization Number

Test Method s: ASTM D-664-58 Ref. 13) ASTM D-974-64 (Ref. 14)

Changes n cidity or lkalinity re ften se d s measures of the deterioration of liquids, particularly in stability tests for oxidation and corrosion. Oxidation of most organic materials can esult n he ormation of acidic compounds.

The erm neutralization number" s ften se d n expressing an acidity or alkalinity of lubricating liquids and hydraulic luids. t s efined s he number of milligrams of potassium hydroxide required to neutralize all the acids present in on e gram of the sample, or the equivalent (in milligrams of potassium hydroxide) number of milligrams of hydrochloric acid required to neutralize all of the bases present n ne gram of the sample. The neutralization number s eneral erm that an efer o he esults of different ests o he test method nd he H f the inal olution us t be specified.

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oils and motor oils that came in contact with extremely hot urfaces. owever, s he emperature anges of hydraulic fluids are increased, the carbon residue and the endency of the hydraulic luid o oke or orm sludges becomes important to system design. Two general methods of determining arbon esidue re currently sed, he Conradson nd he Ramsbottom.

Test Methods : Conradson-Federal Test Method 5001.9 Ref. 15) ASTMD-189-65 Ref. 16) Ramsbottom-Federal Test Method 5002.6 (Ref. 117) ASTM D-524-64 (Ref. 18)

These methods describe procedures for the determination of the carbon residue left after evaporation and pyrolysis of an il. hey re enerally pplicable o relatively nonvolatile petroleum products which ar- tially decompose n distillation t tmospheric ressure. Petroleum products containing ash-forming constituents, such as detergents, will have an erroneously

high arbon esidue depending

pon

he mount of ash formed. (1 ) onradson Test: In he Conradson est, weighed quantity of the

sample luid s placed n rucible nd ubjected o destructive distillation. The residue undergoes cracking and oking eactions during ixed period of severe heating. At the end of the heating period, the crucible with the residue is cooled in a desiccator and weighed. The residue remaining is calculated as a percentage of the original sample and reported as the Conradson carbon esidue.

(2 ) amsbottom est: In he Ramsbottom est, ample of the iquid s

placed in a glass coking bulb having a capillary opening. The ulb with he specimen s placed n metal furnace t pproximately ,020°F. he ample s quickly heated to the point at which all volatile matter is evaporated out of the bulb with or without decomposition while the heavier residue remaining in he bulb undergoes cracking and coking reactions. After a specified heating period? the bulb is removed from the bath, cooled n desiccator, nd weighed. The esidue e- maining s alculated s percentage of the original sample and reported as the Ramsbottom carbon residue.

iron or opper re atalysts or oxidation, many est procedures involve the use of these metals. Two general techniques are used to indicate oxidation stability. The first nvolves measuring hanges n iquid properties caused by the test. The second involves determining the amount of oxygen that has been removed from the air or the system. Relating the oxygen consumed to time

will give the rate of oxidation. A few of the more widely accepted procedures are discussed ere.

3-4.6.2.1 Oxidation-corrosion Test

Test Method : Federal Test Method No. 5308.5 (Ref. 119)

Probably he most idely se d est or oxidation stability s he xidation-corrosion est. his est method s used or testing hydraulic luids nd other highly-refined ils o determine heir ability o esist oxidation and their tendency o orrode various metals. The est s lso used s an ccelerated on g erm storage est.

Five different metal strips-one each of copper, steel, aluminum lloy, agnesium lloy, nd admium plated teel-are arefully leaned, olished, nd weighed. These metal strips are assembled in a pattern, tied together, and the assembly immersed in a sample of the oil. The oil is held at 250T for 68 hr while air is ubbled hrough t. he trips re hen emoved, cleaned nd weighed, nd he esults re recorded s changes in weight per unit area of surface. Each strip is xamined or ny vidence of pitting, tching, r stains. n ddition, he oil ample s examined efore and after the test, and percent changes of neutralization number nd iscosity re determined. everal ariations of the test are used with different metal specimens and/or test temperatures and/or test times. For example, MIL-L-7808E specifies metal strips of steel, silver, aluminum, and magnesium alloys under conditions of 347°F fo r 72 hr . MIL-H-8446B specifies a 72-hr test at 400°F with etal trips of ilver, opper, teel, nd aluminum lloy.

3-4.6.2.2 Steam urbine Oxidation es t

3-4.6.2 Oxidation Stability Tests

A arge umber f xidation ests ave een proposed. All these tests involve exposing the liquid to air or oxygen at elevated temperatures in order to accelerate the rate of oxidation. Since certain metals such as 3-72

Test Method: ASTM D-943-54 (Ref. 20) This test was developed to measure the effectiveness

of antioxidant dditives nd o predict ubricant ife. The procedure is actually a combination oxidation and hydrolytic stability test. Given amounts of the test liquid and water are placed in a large test tube, and a coil

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of iron wire nd opper wire wound ogether in nti- mate contact s completely immersed in he est mixture. The test tube is placed in a bath at 95°C and ir at 3 liters per hour is bubbled through the test liquid/- water mixture. The test liquid is sampled periodically to determine changes n cidity. A apidly ncreasing acidity is taken as the end point of the test. The forma-

tion of sludge deposits n he metal oil an lso e used o ate iquid tability. This procedure has een found to be particularly useful in determining the effectiveness of inhibitors n petroleum products se d s steam urbine ubricants. ince many of hese ame materials are used as hydraulic fluids, the results of the steam turbine oxidation test are often considered in the selection of petroleum-type hydraulic luids.

3-4.6.2.3 Evaporation ests

Evaporation loss tests described in par. -2.8.2 provide measure of oxidation tability. These ests re primarily esigned o easure he iquid olatility. However, if the temperature at which the test is carried out s igh nough hat xidation ccurs, he otal weight lossexperienced by the sample will be a measure of oxidation tability-volatility of the iquid.

3-4.6.2.4 Thin Film Oxidation Tests

A frequent occurrence in the operation of hydraulic systems s he xposure o he tmosphere of a arge

area ofmetal surface covered by a thin film of hydraulic fluid. O ne such case is the extension of an actuator rod. Normal oxidation ests nvolve he se of elatively small urface-to-liquid atios. A est or determining oxidation roperties t arge urface-to-liquid atios has been developed by the Pennsylvania State Univer- sity etroleum efining aboratory Ref. ). he procedure involves assing ir and xygen hrough tube containing a arge mount of metal hain nd small mount of liquid. Changes n iquid properties occurring after a specific est period are measured.

3-4.6.2.5 Dornte Oxidation es t

The Dornte oxidation test s on e of the more common bsorption-type xidation ests or ydraulic fluids. Oxygen is circulated through the liquid which is maintained nder pecified onditions. he otal amount of oxygen absorbed is replaced to maintain the

ratio of oxygen-to-liquid. The amount of oxygen hat must e dded o he ystem o maintain desired pressure s measure of that bsorbed y he iquid. Test data are usually accumulated in terms of amount of oxygen absorbed per unit time. Several variations of this test have been developed. Details on them can be found n Ref. .

3-4.6.3 Thermal Stability Tests

3-4.6.3.1 Penn State Bomb Test

The enn tate om b est escribed n IL-H- 27601 s a widely used thermal stability test. A 2 0 ml sample of the liquid is placed in a stainless steel pressure cylinder with a 46 ml capacity. Catalysts of 0.5 in. diameter ball bearings of M-10 tool steel, 2100 steel, and naval bronze are also placed n he cylinder. The system is purged with nitrogen, ealed at atmospheric pressure, nd he test egun. A temperature of 700°F (371°C) and a nitrogen pressure of 2 0 psig is maintained for 6 hr . Changes in viscosity, weight of the catalyst ball bearings, nd cid or ase number re eported s measure of thermal stability of the iquid.

3-4.6.3.2 High-temperature Test

Test Methods : Federal Test Method 2508 (Ref. 21) ASTM D-2160-66 (Ref. 22)

This method describes a procedure for determining the thermal stability of liquids. The volatile decomposition products are held in continuous contact with he liquid during he est. The method oe s ot measure the temperature at which oil fragments begin to form, but ill ndicate bulk ragmentation ccurring t specified temperature and esting period.

A sample of the liquid is placed in a glass test cell, and he test ell nd ontents are egassed o educe oxidation an d hydrolysis. The cell is then sealed under a vacuum an d held at 00°F 2°F for a period of 24 hr. The sample is observed during the test fo r evidence of insolubles, eparation, r other hanges. he est report ncludes (1 ) test emperature and duration, 2) visual ppearance of the iquid nd est ell, nd 3) changes in neutralization number and viscosity of the

liquid sample.

3-4.6.3.3 Sustained High-temperature Stability Tests

There re o tandardized est procedures or sustained igh-temperature tability s uch. owever,

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when a hydraulic fluid is being considered for use for long periods in a system operating near its upper temperature limit, normal hermal stability data may ot be sufficient to indicate probable performance. In such instances, it is common to test the liquid in a pump loop operating n igh-temperature nvironment. he pump oop est procedures iscussed n ars. -2.5.3

(Shear Tests) or -3.8.2.1 nd -3.8.2.2 Lubrication Tests) re daptable o igh emperature ests. he procedure is to enclose the loop in an oven, and operate the test continuously at the desired temperature for 100 to ,000 hr.

3-4.6.3.4 Low-temperature Stability Test

Although he erm thermal tability" sually m- plies high-temperature tability, roblems an occur with hydraulic fluid stability at low temperatures. Re- fe r to par. -2.14 fo r a iscussion of low-temperature stability nd the various applicable tests.

3-4.6.4 Hydrolytic Stability Tests

Hydrolytic tability s determined y xposing he hydraulic luid o water nd measuring he hanges that occur, under various environmental conditions, in selected properties of the liquid. A problem that often occurs in these tests is maintaining a sufficient contact area etween ater nd iquid o btain measur- able eaction. everal f he ore ommon tests re described.

3-4.6.4.2 Other Hydrolytic Stability Tests

To determine the hydrolytic stability of fluids whose rate of hydrolysis is low, or to predict hydrolytic stability n losed ystems t igh emperatures, metal bomb must be used in place of the beverage bottle. Test procedures are quite similar to those used for the bever-

age bottle est xcept hat o etal trip s dded. Shaking ssemblies, uch s hose vailable rom he American nstrument ompany, re well uited or this est. These particular assemblies oscillate igh- temperature high-pressure reaction vessel 15° at 6 cycles er min. eflux ests present nother general technique. While procedures have not een tandardized, he essential features are that measured amounts of water and fluid are placed in a container and heated to he temperature at which he oil boils. The vapors are condensed, nd efluxing is continued fo r a specified eriod f time. hanges n he luid re determined, and the development of an y acidity in the water

layer is measured. These data are used as an indication of hydrolytic tability. imple storage ests re also measure of hydrolytic stability. Measured quantities of fluid and water are placed in a bottle or other container, agitated, nd tored t esired emperatures or desired period of time. The samples are examined periodically to determine changes in appearance and, at the end of the test, re examined fo r the formation of insolubles, gels, or other physical and chemical changes. Various types of metals, lastomers, urface coatings, etc., an e added o the test ontainers to determine their effect.

3-4.6.4.1 Beverage Bottle Test 3-4.6.5 Radiation esistance Tests

Test Methods : Federal Test Method 3457 (Ref. 23) ASTM D-2619-67 Ref. 24)

This method is used fo r determining the resistance of finished fluids to reaction when in contact with water. It consists of placing 75 g of fluid and 25 g of distilled water in a 7-oz beverage bottle. A cleaned and weighed copper strip is placed in the bottle and immersed in the fluid. he bottle s ealed nd laced n otating mechanism that turns the bottle end over end at 5 rpm for 8 hr in n ven t 00°F. The container s hen removed from the oven, allowed to cool, and examined.

Any nsolubles ormed re emoved y entrifuging. The oil nd water layers are separated nd xamined for hanges n neutralization number, iscosity, nd color. The weight hange of the opper trip s lso reported, and the hysical ondition f he trip is observed.

The sual est methods or determining adiation resistance by hydraulic fluids are based upon radiation exposure followed by determination of changes in the liquid. ertain elected roperties-such s iscosity an d neutralization number, etc.-of the fluid are measured before the test. The fluid is subjected to a given amount of radiation xposure nd he properties re measured after exposure. Changes can vary from complete destruction of the luids nd oss of structural integrity to minor variations in various properties. This is a static test method and gives considerable information n performance of fluids xposed o adiation.

Under development, owever, re various dynamic test procedures. These procedures are based upon the actual operation, in the presence of radiation, of some test evices uch s imulated hydraulic pump est loop containing the test liquid. Also being studied is the

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effect of various ypes of radiation n he est iquid. For xample, amma adiation s nown o av e more destructive ffect han lpha or beta adiation. Testing for radiation effects becomes complicated and expensive. Equipment eeded s xtensive nd ostly. Results ary greatly rom est o est nd lso romsample o ample. onsiderable ffort s eing x-

pended by the military on studies of potentially useful hydraulic fluids and heir radiation esistance.

3-5 CORROSIVENESS

In ts roadest eaning, orrosion efers o he deterioration of a metallic surface by chemical or electrochemical action; a familiar example is the rusting of iron. The corrosiveness of a hydraulic luid elates o its endency o promote or ncourage orrosion n hydraulic system. t is obviously desirable to maintain the corrosiveness of a hydraulic fluid at as low a level as ossible.

The corrosiveness of a hydraulic fluid, usually at its lowest value when the fluid is ne w and unused, can be affected by a number of variables such as temperature, load, moisture, chemical nature of the liquid, oxidation stability, the type and amount of degradation products formed, he dispersion of the products n he system, and umerous ther ariables. nly ew f hese variables, however, are parameters of the liquid. Varia- bles such as temperature, oad, and exposure to moisture, tc., re ystem echanical actors nd an- through proper system design an d the use of the correct hydraulic fluid-be controlled within a range of acceptable limits. Fluid parameters-those variables that relate to the corrosiveness of the liquid such as chemical nature and oxidation stability-are fundamental properties of the liquid and cannot be varied except by the use of additives (see Chapter ).

3-5.1 CHEMICAL CORROSION

Purely hemical orrosion s robably he os t prevalent type of corrosion found to exist in fluid power systems. lthough tarting apidly, t ay ften become low as soon as a layer of corrosion products has been ormed n he metallic surface. f, owever, he layer r orrosion roducts re eing ontinually cracked or removed, corrosion will continue at itsorigi- nal rate. Of the various types of corrosion, the two that occur in most systems are oxidation and acidic corrosion. Oxidation is limited to the surface of metals and

its esults re xhibited y n ccumulation of metal oxides. Acidic corrosion efers to the deterioration of the metallic surface caused by the metal actually being dissolved y cids nd ashed way, eaving itted urface.

Rusting is the oxidation of the base iron in the metal structures. he oxidation s sually atalyzed or n-

creased by the presence of dissolved air and water in the system iquid. Prevention of oxidation s theoretically the easiest corrosion action to control. Simple exclusion of air nd moisture rom he ystem ould liminate rusting. owever, ecause t s lmost mpossible o completely exclude all air and moisture from a hydraulic ystem, numerous dditives re se d s oxidation and orrosion nhibitors see Chapter ).

Oxidation of the hydraulic luids while n se roduces cid-type products which an apidly ncrease the corrosiveness of the fluid. t is, therefore, desirable to maintain igh evel of oxidation tability n he fluid. There are numerous inhibitors which can reduce

the cid orrosion endencies of a hydraulic luid. A discussion of the various corrosion inhibitors and their mode of action s presented n Chapter .

The orrosive endencies of a iquid re requently increased by the presence of various metals which ac t as catalysts. Copper is a common example. Many iquids ecome much more orrosive han sual n he presence of copper; thus several of the test procedures for determining orrosion properties of liquids make use of a copper catalyst. The problem s basically on e of liquid-metal ompatibility nd s iscussed n ar . 3-6.1.

3-5.2 ELECTROCHEMICAL CORROSION While lmost ny hemical eaction an e alled

electrochemical, he erm s sually imited o ases with spatially separated anodic and cathodic areas, o that corrosion is accomplished by electric current flowing for a perceptible distance through he metal. t s not ecessary o have tw o metals for electrochemical corrosion. A ll that is needed is the metal, a material of a ifferent lectric potential nd onductance path between them. A corrosion product or liquid can serve as the source of the second electric potential (Ref. 25).

Galvanic orrosion s probably he most ommon form of electrochemical corrosion. Galvanic corrosion occurs hen issimilar etals, n lectrical ontact with each other, are exposed to an electrolyte. A current, alled alvanic urrent, hen lows rom ne metal to the other. Galvanic orrosion s that part of the resulting corrosion of the anodic (positive) member of the metal couple.

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Many ydraulic luids re ot oo d lectrolytes when ew nd o ot romote alvanic r lectrochemical corrosion. However, contaminants that enter or orm n he luid uring se , nd om e ypes f additives, may ive he iquid lectrolytic properties. Several precautions can be taken to stop or reduce the electrochemical ction f he alvanic ouple nd

reduce the corrosion; e.g., using similar metals, insulat- ing he metals, r liminating he lectrolyte. hese steps are frequently impractical and other precautions, such s sing corrosion nhibitors, must e taken.

3-5.3 CORROSIVENESS TESTS

Numerous est ethods av e een roposed nd developed or determining he corrosive properties of liquids. While most of the ests re universal n hat they re designed or an y yp e of liquid or ubricant, certain tests have been developed specifically for gear lubricants, or hydraulic luids, r or other pecial liquids. These corrosiveness tests fall into three general categories: (1 ) metal-liquid tests where a metal surface is xposed o he iquid or a iven ength of time t given onditions, 2) og r umidity abinet ests where trip of metal s oated with he iquid nd exposed to extremely humid conditions fo r a predetermined period of time, nd 3) ngine ests where he liquid s ested n gear bo x of an engine under controlled conditions.

3-5.3.1 Metal-liquid Corrosiveness Tests

A arge number of metal-liquid orrosiveness ests have been developed. Most of these tests are similar in that metal ample s xposed o he iquid nder controlled conditions. The metal is then examined for evidence of corrosion nd he iquid s xamined or changes in properties. These tests can also be considered s iquid-metal ompatibility ests. wo of he more ommon ypes of ests re described nd lso noted in able -1 2 long ith ther ests f he same ype.

(1 ) Oxidation-corrosion Test Test Method : Federal Test Method 5308.5 (Ref. 19)

This test is probably the most commonly used liquid- metal corrosiveness test. It is described in detail in par. 3-4.6.2.1. n his est, ive different metal trips-one each of copper, teel, luminum alloy, magnesium l- loy, and cadmium plated steel-are assembled in a pattern and the assembly is immersed n sample of the

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test liquid and is heated at 50°F for 68 hr while air is bubbled through the liquid. After the test, the strips are examined for evidence of pitting and corrosion, and the liquid sample itself is examined for changes in basic properties. The oxidation-corrosion est, or variations of it, is frequently called for in property specifications of military hydraulic fluids. The acceptable corrosion limits for several military specification hydraulic fluids, as determined by the oxidation-corrosion test (or variations) are iven in Table -13.

(2 ) Copper Corrosion Copper Strip) est

Test Methods : Federal Test Method 5325 (Ref. 26) ASTM D-130-65 Ref. 27)

This method describes a procedure for the determination of the corrosiveness to copper of fuels, gasolines, cleaners, ue l oils, nd other petroleum products.

A polished copper strip is immersed in a 30-ml sample of the liquid nd heated t he emperature normally 22 ° or 212°F) and fo r the time (normally 2 to 3 hr) called for in the liquid specification. At the comple- tion of the test period, the copper strip is removed and compared with a series of copper strip corrosion standards (available from ASTM). The results are reported as the number of the corrosion standard with which the test trip ompares. tandards ary rom o. a (slight tarnish) to No. 4c (corroded glassy or jet black).

3-5.3.2 Humidity-type Corrosiveness Tests

Several corrosiveness test procedures using a fog or humidity abinet av e een eveloped. The ests re similar in that a metal specimen is coated with the test liquid and placed in a cabinet with constant high humidity. In some instances the fog is treated with various chemicals o imulate ctual onditions, .e., odium chloride salt dded o simulate sea water. These tests are not basically corrosiveness tests; they are primarily intended o determine the orrosion-protecting uali- ties of a liquid in the presence of a corrosive environment. Two of the more ommon est procedures re described and also listed in Table 3-14 along with other tests of the same type.

(1 ) Corrosion-fog Cabinet Test Method : Federal Test Method 5312 (Ref. 28)

This method is used for determining the rust inhibiting properties of nonaqueous liquids, greases, and preservative compositions. The method consists of coating low-carbon, cold-rolled steel plates with the test liquid, rotating the plates in a fog cabinet under specified con-

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TA BL E 3-12. LIQUID-METAL CORROSIVENESS TEST M E T H O D S

Test Method Title Procedure

Federal Test Method Corrosiveness and Oxidation 5 etal trips—copper, teel, luminum, mag- 5308.5 Stability nesium, cadmium plated teel,—immersed n

test liquid fo r 168 hr at 250 °F , ith air agitation.

Federal Test Method Copper Strip Corrosion Polished copper strip immersed in test liquid 2 5325 ASTMD-130-65 to 3 hr, 122°F(50°C) or 212°F (100°C).

Federal Test Method Corrosion at 450°F Copper nd ilver strip immersed in test liquid 5305 for50hr,450°F.

Federal Test Method Lead Corrosion Strips f ead nd opper re otated n est 5321 liquid r, 325°F, air bubbled through liquid.

Federal Test Method Copper Stain Polished opper trip mmersed n se d est 5324 liquid r, 00°F; itrogen ubbled hrough

liquid.

Federal Test Method Rust Inhibiting Drop f water laced n heet-steel lates 5311 (Static Water Drop) immersed in test liquid, one week, 140°F.

Federal Test Method Rust Preventing- Cylindrical steei specimen immersed n est 4011 ASTMD-665-60 Steam Turbine Oils liquid-water mixture, 24 hr , 140°F'(60°C)

Federal Test Method Beverage Bottle Test Copper strip immersed in water-test liquid 3457 ASTM D-2619-67 mixture, 48 hr , 200°F.

References:

(1) ederal Test Method Standard No. 91a, Test Methods 3457, 5308.5, 5325,5305, 5321, 5324,5311,4011.

(2 ) STM Standards 967, esignation -130-65, ar t 17, . 2 ; esignation -665-60, art 17, . 53; Philadelphia, American Society for Testing Materials, 967.

(3) STM Standards 1969, esignation D-2619-67, Part 7, . 997; Philadelphia, American Society for Testing Materials, 1969.

ditions of temperature and humidity as called for by the liquid pecifications, nd bserving he lates or he formation of rust. The esult s eported s he im e required for three 1-mm diameter rust spots to form on the surface of at least tw o plates or until he specified test period required by the fluid specification s om - pleted, whichever comes first.

(2 ) Protection-salt Spray Test Method : Federal Test Method 4001 Ref. 29) This method is intended for the determination of the

corrosion resistance of a fluid in the presence of a salt- type atmosphere. teel test specimens are coated with the test fluid and suspended in a fog chamber. The fog consists of an atomized spray of a solution of 20 parts,

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TABLE 3- 13 .

OXIDATION-CORROSION LIMITS OF SEVER AL MILITARY HYDR AULIC FLUID SPECIFICATIONS

Pet ro leum Hydraul ic Fluids

MIL-H-5606B

MIL-H-6083C

MIL-H-13866B

MIL-H-27601A

;P hospha te Ester MTL-H-19457B

Silicate Ester MIL-H-8446B

Tes t Method or

Tes t Descr ip t ion

Federa l N o . 5308.5 ( 1 6 8 hr a t 250°F)

Federal Wo . 5308.5 (168 hr t 250°F)

168 hr a t 212°F

Federa l N o . 5308.5 (48 hr t 347°F)

168 hr t 130°F

Federa l No. 5308.5 ( 7 2 hr t 400°F)

Fluid Changes

Metal Changes

-p W . •H

<l > O «i o u m a•H n > o

- 5 , +2 0 at 130°F

- 5 , +2 0 at 130°F

- 5 , +20 a t 100°F

- 5 , +20 at 100°F

r 3 5 a t 210 °F

3 tu o

< 0.20

<.0.30

< 0.5 (Total)

< 0.2 (Total)

< 0.1 (Total)

Weight Change, mg/em

0.6

0.6

- 0.2

t 0.6

0.4

± 0.2

t 0. 2

0.2

± 0.2

Z 0. 2

I 0.2

+ 0.2

0.2

t 0.2

+ 0.2

- C te a H

•H m

S3 O o ^ •Ö +> >H 0) w + > oC O rH bo u PH C rH

H •H £> -Ö U +> -H rH w o +> •H -r + O CO PM >

± 0.2

+ 0.2

( + 0.2 fo r Silver)

t 0.2

0.2

(i 0.2 fo r B r a s s an d Zinc)

t .2 Silver)

None t

2 0X

None t2 0X

None t

2 0X

None

None t20 X

U O ) cu s ft p, n H O

O

< ASTM No. 3

SlightEtching

SlightDiscolor

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TABLE 3 -1S .

GEAR-BOX CO RRO SI V E N E SS T E ST M E T H O D S

Test Method Title Procedure

Federal Test Load-carrying, Wear, The test unit is a 3/4-ton Army truck hypoid rear-axle Method 5317 Stability, and Corrosion carrier, 5:83 to ratio. The test fluid is used as the

Characteristics lubricant, temperature maintained at 200°-250°F, load of

32,311 in.-lb at 62 rpm. Test is run for 30 hr. Federal Test Moisture Corrosion Test unit is Chevrolet passenger car rear axle. 25 ml of Method 5318 Characteristics - distilled water is added to the test fluid, temperature of

Universal 180°F; 2,400 rp m for 4 hr test. Unit is then stored for 10 days, opened an d examined for corrosion.

Federal Test Moisture Corrosion Test unit is a Spicer differential assembly. One ounce of Method 5326 Characteristics-Gear distilled water is added to test fluid temperature of

Lubricants 180°F; 2,500 rpm for 4 hr. Unit is then stored as required by fluid specification, opened an d examined for corrosion.

References: (1) Federal Test Method Standard No. 91a, Test Methods 5317, 5318, 5326.

construction and the elastomers used for sealing. lso important are the various surfacetreatments of materials in or near the system, such as paints and special surface finishes. econd, here hould e compatibility of the hydraulic luid with he ystem nvironment. Break- age, eakage, nd pillage ll oo frequently bring he hydraulic fluid into contact with its immediate environment. Of concern here are paints, fabric or plastic lin- ings or overs, nsulation nd lectrical wiring, nd structural materials se d near he hydraulic ystem. Third, here should e compatibility of the hydraulic

fluid with other liquids and lubricants it may contact. Of concern here is additive susceptibility, use of substitute hydraulic fluids, and choices of lubricants for the system. ach of these actors must e xamined n- dividually nd n ombination or ompatibility with the hydraulic fluid.

There is often difficulty in determining the compatibility of a hydraulic luid with he hydraulic ystem. Because of the wide range of operating conditions and the large number of possible materials, there have been very ew Federal or ASTM est procedures developed for etermining ompatibility. When uestion f compatibility rises, he normal est procedure s o

expose the material in question to the hydraulic fluid (under imulated ervice onditions, f possible) nd determine changes in the material. One unique facet of this type of procedure is that emphasis is placed on the material and no t n the hydraulic fluid. The question then rises whether compatibility is a property of the

hydraulic fluid or of the material. Because compatibility is an interaction between a hydraulic fluid and enu- merable other materials, hydraulic fluid specifications usually nclude imited number of requirements n compatibility. The most frequently encountered examples re ubber welling equirements. lso, ost hydraulic luid pecifications equire hat ll iquids qualified nder he pecification e ompatible with each other.

3-6.1 HYDRAULIC LUID COMPATIBILITY WITH METALS

Compatibility of a hydraulic luid with he metals used n hydraulic ystem s most mportant. are must be taken hat ystem esign excludes ll metals that re damaged y he iquid or hat degrade he liquid. Liquid-metal compatibility, in its strictest sense, includes only chemical interrelationships; however, the topic s broadened here o nclude ny nfluence he hydraulic fluid may have on metal fatigue and cavitation.

It is common practice to use copper, silver, bronze,

aluminum, steel, magnesium, and many other metals as structural aterials n ydraulic ystems. ost e- troleum-base hydraulic fluids are not normally affected by hese materials lthough om e metals, specially copper, ac t as catalysts after degradation starts in some petroleum liquids. However, many of the ewer

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synthetic fluids may not be compatible with on e or more of the conventional metals. For example, diester fluids such as the turbine engine oil MIL-L-7808 are affected by copper and its alloys above 200°F. At 500T, which is 200°F above its maximum usable temperature, uc h a diester still has a life of 8 to 2 hr in a sealed system. If a small piece of brass or copper is present, he fluid

is reduced to a thick, black, molasses-like substance of high cidity and ou l odor within n hour (Ref. 2). Liquid-metal ompatibility may e measured y

number of tests. These techniques sually nvolve x- posing the metal to the liquid under a variety of conditions and determining any changes in the liquid or the metals. Many of the tests mentioned in the paragraphs on hemical tability par. -4.1) r orrosiveness (par. -5) are quite useful an d av e been widely sed.

Difficulty ften rises n ttempting o elate est conditions o ctual ervice onditions. any onditions hat occur n ervice annot e nticipated nd incorporated nto he est. ne xample s alvanic

corrosion. ydraulic luids may ecome lectrolytes between dissimilar metals during use and cause considerable orrosion. t hen ecomes necessary o tudy metal-to-metal ouples n he presence f andidate hydraulic luids. Most luid manufacturers av e onducted extensive research into the liquid-metal compatibility of their products and data are available to pros- pective purchasers. n most cases, hydraulic fluids are compatible with all common metals used in construction of hydraulic systems, and the fluid manufacturers only provide data fo r hose nstances where he luid and metal re not ompatible.

3-6.1.1 Metal atigue

Metals fail through fatigue when they are subjected to excessive local stresses, either cyclic or unidirectial. In both cases, the fatigue life of a metal can be affected by ts nvironment. f the nvironment s orrosive, resistance to fatigue is reduced (Ref. 25). The resultant amage rom he ombination f corrosion nd stress will be worse than the damage produced by either individually. Two basic types of combinations of stress and orrosion re ecognized-stress orrosion here the tress s tatic nd ensile, nd atigue orrosion where the stress s cyclic.

The mode of failure in both instances is similar. A s a esult of fatigue, orrosion, or a combination of the two, small pits or cracks are produced in the metal. The corrosion then acts on the bottom of the cracks or pits in such a way as to produce a greater stress concentration han would e produced by tress lone. Failure

occurs from the progression of the cracks across a section of the metal.

For each metal, the degree to which it is affected by stress corrosion is associated with its environment. The hydraulic fluid constitutes the environment "seen" by the metals n he hydraulic ystem. f the hydraulic fluid is corrosive to the metals, the fatigue resistance of

the metals will be reduced. However, the environment frequently will ot e as corrosive to he metal f the stresses are absent.

The effect of the hydraulic fluid on the fatigue life of a metal s not problem hat occurs ery ften. The degree of corrosiveness equired o produce ignificant eduction n atigue ife s sually much greater than normally occurs n hydraulic ystems. For his reason, lmost o work as een done n his rea. Because of he protective nature of many ydraulic fluids and the use of corrosion inhibitors, the corrosion level of most hydraulic fluids tends to be low. If excess corrosiveness is present, it is usually an indication that

the limits of the hydraulic fluid are being exceeded, or that excess contamination is present. In such cases, the presence of the orrosiveness tself is dangerous nd ca n produce system malfunction.

3-6.1.2 Cavitation

Cavitation has been defined as the "process of formation of the vapor phase of a liquid when it is subjected to reduced pressure at constant ambient temperatures" (Ref. 30). Cavitation damage occurs when the resultant vapor avities n he luid ollapse near metal surface on exposure to high pressure. The exact mechanism y hich amage ccurs s ot nown, but most uthors uggest orm f echanical erosion or orrosion.

Cavitation damage is often more severe if the cavities consist of a vacuum or of the vapor of the liquid than if they contain some foreign gas, such as air. With the trend toward the use of pure fluids with high pressure differentials nd igh requency vibration, avitation becomes an increasingly mportant problem.

Erosion or "wearing away" of the metal surface by action of the liquid producing a "pelted" surface seems to be the most prominent theory for cavitation damage.The rosion s aused y he liquid eaving he metal surface and creating a vacuum into which air and liquid vapors are released rom he iquid o orm a ubble. The bubble is maintained until an area of high pressure is encountered and the bubble collapses suddenly, producing a hammering" ffect. When his action s re - peated n apid uccession, he metal s worn way.

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Other mechanical ffects such as noisy operation and vibration are produced due to the repeated "hammering" ffect of the collapsing bubbles (Ref. 31).

Cavitation damage can occur in almost an y component in a hydraulic system. However, the damage usually occurs where the high pressure-low pressure-high pressure sequence equired occurs often, apidly, nd

with high pressure differentials. The components most subject o damage re he hydraulic pump, Venturis, and alves.

Cavitation in pumps occurs when the liquid cannot enter the pump fast enough to fill the volume or when the liquid cannot keep up with moving pump elements. Cavitation n enturis ccurs hen he igh luid velocity n he hroat rops he pressure elow he vapor pressure of the liquid. Cavitation in valves occurs

in a manner similar to that in Venturis. Once cavitation is established in a pump, valve, or venturi, the flow rate remains constant unless some physical change is made- such s increasing the throat opening in venturi.

There are numerous ariables that ffect cavitation damage. om e variables are mechanical factors of the system esign nd ome re properties of he luid.

Mechanical actors nclude uction pressure, enting, liquid elocity, ilm hickness, emperature, nd urface roughness. Liquid properties that effect cavitation are vapor ressure, iscosity, ensity, ulk modulus, surface tension, and additives. The effect of these variables n avitation s iven n Table -16.

A distinction must be made between the amount of cavitation nd he xtent of cavitation amage. requently, eduction n he mount of cavitation will

TABLE 3 - 1 6 .

E FFE CT O F M E CH A N I CA L A N D LIQUID VARIABLES O N CAV I TAT I O N 130

Variable Cavitation Comment Mechanical Factors:

Increasing Suction Pressure

Reduced Increased pressure maintains a positive pressure throughout pump; reduces probability of low pressure cavity formation in pump.

Venting Reduced Venting reduces cavitation if it de-aerates the system an d removes high vapor pressure dissolved gases.

Increasing Liquid Velocity

Increased

Reducing Lubricant Film Thickness

Increased Cavitation is increased probably because the film is in compression and pressure differences are large.

Increased Temperature

Increased Cavitation an d cavitation damage are probably increased du e to higher vapor pressure.

Increased Surface Roughness

Increased Cavitation increases, probably because of the creation of more high-low-high pressure sites.

Liquid Factors:

Lower Vapor Pressure

Reduced

Higher Viscosity Reduced

Higher Density Increased High Bulk Modulus Increased

Increased Surface Tension

Reduced

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result in n increase in cavitation damage. This is be - cause many of the ariables hat end o educe he amount of cavitation y educing he ormation nd growth of cavities, also increase the collapse rate, and, therefore, the rate of energy released when the cavities collapse. This action ha s the effect of concentrating the energy into a smaller area and producing more severe

damage. O ne example of this "double-acting" effect of inhibiting cavitation occurs when the vapor pressure is reduced. Lower vapor pressure tends to inhibit the formation of cavities but results in a lower pressure inside the cavities that do form, thereby increasing the rate of collapse and the amount of damage.

Cavitation mainly occurs n wo general ituations -thin films of lubricants, and full streams of liquid. In both ases, he igh-low-high-pressure equence s found. O ne instance of cavitation in a thin film is shown in ig . -55. High pressure occurs n he gear eeth surfaces as the lubricant approaches the pitch point and is compressed. The low pressure, cavity formation, and

cavity collapse occur as the lubricant passes the pitch point. Cavitation occurs in the freestream whenever an orifice r enturi s ncountered hat roduces he high-low-high pressure sequence as shown in Fig. 3-56. The venturi effect can occur in valves, orifices, fittings, and other.components of a hydraulic ystem.

3-6.2 ELASTOMERS

Almost ll eals nd packings se d n hydraulic system re made rom ynthetic r natural ubbers which av e n lastomer s he main ngredient. An

elastomer is a material exhibiting little plastic flow, and quick and nearly complete recovery from an extending force (Ref. 32). Such materials are usually modified by

additives nd reatments o ak e inished lastic compound. hile he number of basic lastomers s small, he ariety of finished ompounds hat an e made is almost infinite. It is usually possible to develop a compound hat s ompatible with hydraulic luids under an y normal environmental onditions.

The hydraulic luid sually as more effect n he

seal or packing compound than the compound ha s on the hydraulic fluid. In most instances, the compound is almost inert as far as an y harmful effects on the liquid are concerned. However, om e iquids attack and e- stroy some seal materials. The usual method of determining if a liquid and an elastomer are compatible is to measure selected properties of the elastomer before and after immersion in the liquid. The common properties used o ompare or valuate various lastomers re described in Table 3-17. Other properties (not listed in Table 3-17) of importance are corrosive effects on metals, hermal esistance, ermeability, oefficient f thermal expansion, nd oefficient of friction.

The greatest difficulty in evaluating liquid-elastomer compatibility s he election of test onditions. eals are subjected to a wide variety of operating parameters including variables such as temperature, pressure, load, speed, abrasion, and stop-start conditions. In addition, changes in the chemistry of the liquid occur during use by oxidation, hermal rocesses, orrosion, nd on - tamination; here re lso ifferent equirements or static or dynamic eals. Evaluation of dynamic eals must ake nto ccount he omplete ange of conditions expected in service because a change in the conditions within the expected range may have an effect on the compatibility. n general, the final determination of

liquid-elastomer compatibility must be made in the intended ystem or imulated ystem) ver he n- ticipated range f perating onditions.

High ressure

Fig. 3-55. Cavity Formation and Collapse Between Rollers or Gear Teeth 130

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Orifice

Fig. 3-56. Cavity Formation and Collapse in an Orifice 130

TA BL E 3 -17 .

PROPERTIES OF E L A STO M E RS

Property Definition

Hardness

Tensile Strength

Ultimate elongation

Modulus

Volume change

Compression se t

Hardness measured on the Share A durometer scale, calibrated to a durometer reading of 100 on flat glass.

The force in ps i required to rupture a standard specimen.

Th e increase in length, expressed as a percent of original length, a standard specimen will undergo before breaking.

The stress at a predetermined elongation, usually 00 percent.

The change in volume, expressed as a percent of originalvolume, of an elastomer after contact with a media (hydraulic fluid).

The percent of original deflection by which an elastomer fails to recover in air after a fixed time under specified load and temperature.

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3-6.2.1 Basic Elastomer Materials Several elastomer materials have been developed for

use as seals and packings. A brief description of the 5 most commonly used basic types of elastomers is given in the paragraphs which follow (Ref. 32). Some common trade names and recommended se s are given in Table 3-18. A comparative rating of various properties is iven n Table -19. able -20 ists data n he compatibility atings of several commercial hydraulic fluids with he elastomers described.

(1 ) itrile or Buna N (NBR) Temperature Range:-65° to 250T (-54° to 21°C) This lastomer s opolymer f butadiene nd

acrylonitrile. As the nitrile component increases, resistance to petroleum base liquids increases, but low temperature flexibility decreases. Nitrile is the most widely used elastomer today. Nitrile compounds are superior to most elastomers with egard o compression et or cold low, ear, nd brasion esistance.

(2 ) una S Rubber (SBR or GRS) Temperature Range:-65° to 25°F (-54° to 07°C) SBR rubber is best known under its former designa-

tion of Buna S or GRS, which refers to the U . S. Gov- ernment rubber made during World War II . SB R and natural rubber account for almost 90 percent of world rubber consumption. These tw o materials are not generally se d n eals except or hose n utomotive brake systems).

(3 ) utadiene Rubber (BR) Butadiene (polybutadiene) has properties similar to

natural rubber. It is not quite as good as natural rubber, but n om e cases exhibits mproved ow emperature characteristics.

(4 ) utyl Rubber (IIR) Temperature Range:-65° to 25°F (-54° tc 07°C) Butyl ubber s n ll petroleum product made y

co-polymerizing isobutylene and isoprene. Brominated and chlorinated butyl rubbers are also available. nner tubes and the inside layer of tubeless tires account for most of the butyl rubber consumption. Butyl has excellent esistance o permeation nd s se d n ac - uum pplications.

(5 ) hloroprene Rubber (CR) Temperature Range: -65° o 00°F (-54° to 49°C) Chloroprene rubbers (known as neoprene) are

homopolymers of chloroprene (chlorobutadiene). They

were an arly ynthetic ubber. Chloroprene tends o crystallize in a stressed condition at low temperatures.

(6) hlorosulfonated Polyethylene CSM) Temperature Range:-65° to 250T (-54° to 21°C) C SM ubber has oo d cid esistance but ts me-

chanical roperties, ompression, nd permanent-set

characteristics re ess han esired or eal pplications.

(7) thylene Propylene Rubber (EPM) Temperature Range: -65° o 00°F(-54° o 49°C) Although EPM rubber was introduced only rece ntly,

its use ha s become widespread because of its excellent resistance to the widely used phosphate ester-type hy - draulic luids.

(8) luorocarbon Rubber (FPM) Temperature Range:-20° to 400°F (-29° to 204°C) Fluorocarbon rubbers were first introduced in the mi d-

1950's and have grown to major importance. They will withstand emperatures s igh s 00°F 316°C) or short periods and as low as-65°F (-54°C) in some static uses. They exhibit maximum resistance to deterioration by est nd functional luids.

(9 ) soprene Rubber-Synthetic IR) Isoprene ubber polyisoprene) s ynthetic las-

tomer with the same chemical composition s atur-

al ubber. (10) Natural Rubber-Natural Polyisoprene (NR)

Natural rubber is not used to a great extent for seals and packings. Petroleum liquids seriously attack natural ubber compounds. Like neoprene, natural ubber tends to crystallize in the stressed condition.

(11) Polyacrylic Rubber (ACM) Temperature Range: 0° to 350T (-18° to 77°C) ACM ubber as utstanding esistance o e-

troleum fuels and oils. There are numerous types of the ACM rubber available and al l are polymerization products of acrylic acid esters. The greatest usage of ACM rubber is in automatic transmission and power steering gear seals.

(12) Polysulfide Rubber Temperature Range:-65° to 225°F (-54° to 07°C) Polysulfide ubber as ne f he irst ynthetic

polymers; t s prepared from dichlorides and sodium polysulfides. t has unique combinations of solvent re - sistance, ow emperature lexibility, nd xygen nd ozone resistance. It ha s poor heat resistance, mechani- ca l trength, nd ompression et.

(13) Polyurethane Rubber Polyurethanes have superior mechanical and physi-

cal properties. However, they cannot withstand water, acids, ketones, and chlorinated or nitro hydrocarbons. They have poor ompression et nd end o often excessively above 250°F (121°C). Because of the many polyurethane rubber compounds, with minimum temperature at which each may be used varying from compound to compound, no lower temperature restriction can e stated.

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TA BL E 3-18 .

COMMON TR A D E N A M E S A N D R E C O M M E N D U SE S O F BASIC T Y PE S O F E L A STO M E RS

E l a s t o m e r Tr a d e I Tames an d Ma r f a c t n r e r s R e c o m m e n d e d u s e s

llitrile or B u n a V < (NBR) C h e m i g u m C-ocdyear Tire Rubber Co. G e n e r a l p u r p o s e sea l in-

B u t a p r e n e F i r e s t o n e Ti r e £ Rubber Co. P e t r c l eu m o i l s an d f l u id s P a r ac r i l I 'augatuck C h e m i c a l Wa t e r H y c a r G o o d r i c h Chemic-il Co. Siliccr.e g reases an d oils H e r e c r o l H e r e s i t e lc C h e m i c a l Co. Di-es te r r a s e l u b r i c a n t s (MTL-L-760S) P o l y s a r K r y n a c P o l y m er Co rp . , Limi ted E t h y l e n e g l y c o l b a s e f l u id s (Hydro lubes)

B u n a 5 ( S B R or GRS) (Too n u m e r o u s ) Automot ive b r a k e f l u i d

A l c o h o l s ( l o w m o l e c u l a r weight ) Wa t e r

B u t a d i e n e (ER) A m e r i p o l CB G o o d r i c h - G u l f Chemica ls , Inc. B u d e n e Goodyear Ti r e & Rubber Co. C i sd en e A m er i can S y n t h e t i c Rubber Co rp . Diene F i r e s t o n e S y n t h e t i c Rubber Corp.

B u t y l ( IIR) En Ja y B u t y l E n j ay C h e m i c a l Co. P h o s p h a t e es te r type h y d r a u l i c f l u id s H y c a r 2202 F . F. G o o d r i c h C h e m i c a l Co. (Sk v d ro l . FRYOUEL(Cel lu lube) . Pydrau l ) P o l y s a r B u t y l P o l y m e r Co rp . , Limi ted Ketones (MEK, Acetone)

S i l i c o n e f lu ids an d g r e a s e s

C h l o r o p r e n e (CR) Neoprene E, I . duPont de N e m o u r s Co. R e f r i g e r a n t s (Fre o n s , NH3) H i g h a n i l i n e poin t p e t r o l e u m o i l s Mild ac id r e s i s t a n c e S i l i c a t e e s t e r l u b r i c a n t s

C h l o r o s u l f o n a t e d P o l y e t h y l e n e (CSM) H y p a l o n E. I. duPont de Nemours Co.

E t h y l e n e N o r d el E. . duPont de Nemours Co. P h o s p h a t e es te r b a s e h y d r a u l i c f lu ids ( S k y d r o l , FRYQUEL(Cel lu lube) , Pydraul ) 1

P r o p y l e n e R o y a l e n e N a u g a t u c k C h e m i c a l S t eam (t o 400°F) (204°C) Wa t e r

E n j ay EPR E n j ay C h e m i c a l Co. Si l icone oils an d g r e a s e s D u t r a l M M o n t e c a t i n i Soc. Gen. Dilu te ac ids Olethene Avisun Co rp . Dilu te a l k a l i e s [

Ketones {MEK, ace tone) A l c o h o l s

F l u o r o ca r b o n (FPM) Vi t o n E. . duPont de Nemours Co. P e t r o l eu m o i l s F l u o r e l M i n n e s o t a Mining & . Mfg . Co. Di-es te r b a s e l u b r i c a n t s

(MIL-L-7808, MIL-L-6085) S i l i c a t e - e s t e r b a s e l u b r i c a n t s

(MLC 6200, M0 8 5 1 5 , OS-45) Si l icone f lu ids an d g r e a s e s H a l o g e n a t e d h y d r o c a r b o n s \

( c a r b o n t e t r a c h l o r i d e , t r i c h lo ro e th y le n e ) . Selec ted p h o s p h a t e es te r f lu ids Acids

I s o p r e n e - S y n t h e t i c (IR) A m e r i p o l SN G o o d r i c h - G u l f C h e m i c a l s , Inc .

C o r a l F i r e s t o n e Ti r e & Rubber Co. N a t s y n Goodyear Ti r e & Rubber Co. S h e l l IR Shel l C h e m i c a l Co.

F o l y a c r y l i c (ACM) C y a n a c r y l A m e r i c a n C y a n a m i d Co. H y c a r 1042 B . F. G o o d r i c h C h e m i c a l Co. P o l y s a r K r y n a c 880-Polymer Co rp . , Ltd. T h i a c r i l T h i o k o l C h e m i c a l Co rp .

P o l y s u l f i d e FA P o l y s u l f i d e Rubber T h i o k o l C h e m i c a l Co rp . Mixtures of p e t r o l e u m so lvents , ke tones , an d e thers

ST P o l y s u l f i d e Rubber T h i o k o l C h e m i c a l Co rp . ZR-300 P o l y s u l f i d e Rubber T h i o k o l C h e m i c a l Co rp .

Si l icone (Si) S i l a s t i c Do w Coming Co rp . H i g h - a n i l i n e poin t o i l s No t r a d e n a m e G e n e r a l E l e c t r i c D r y h e a t No t r a d e n a m e U n i o n Carbide & Carbon C h l o r i n a t e d d i - p h e n y l s

P l u o r o s i l i c o n e (FSi ) LS Do w Corning Co rp .

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TA B L E 3-19.

C O M PA R AT I V E P R O P E RT I E S O F C O M M O N LY USED E L A S T O M E R S

« C 3

03 ^ — '

« a 2

CO cd O o

ö S CO

CO

a 3

03

03 ^ a> C <L >

+-» 3

S3

P? >—t

3 03

o ?

S u p< •o o 2o C

oouo

e

P

y

h

e

C

M 1 u C u > . O £ e > » •5 w

1 a o g o O O 3 E

c? o C . u o ta > > 3

PH

<L > •3

1 o

OH

• 3 M

1 o OH

o o CO

c o es u H

Ozone resistance Weather resistance Heat resistance

p F G

P F FG

P F F

GE GE GE

GE E G

E E G

E E E

E E E

P F F

P F F

E E E

E E P

E E FG

E E E

E E E

Chemical resistance Oil resistance Impermeability

FG E G

FG P F

FG P F

E P E

FG FG G

E F G

E P G

E E G

FG P F

FG P F

P E E

G E E

P G F

EG FG P

E E G

Cold resistance Tear resistance Abrasion resistance

G FG G

G FG G

G GE E

G G FG

FG FG G

FG FG G

GE GE GE

F F G

G GE E

G GE E

P FG G

G P P

G GE E

E P P

E

E

Set resistance Dynamic properties Acid resistance

GE GE F

G G F

G F FG

FG F G

F F FG

F F G

GE GE G

G GE E

G F FG

G E FG

F F P

P F P

F F P

GE P FG

P P E

Reinforced tensile Electrical properties Water/steam resistance Flame resistance

GE F FG P

GE G FG P

E G FG P

G G G P

G F F G

F F F G

GE G E P

GE F FG E

E E FG P

E G FG P

F G P P

F F F P

E F P P

P G FG F

E E G

E-Excellent G-Good F-Fair P-Poor -No reliable data

[From: Seal Compound Manual Used by permission of Parker Seal Company.]

(14) ilicone Rubber (Si) Temperature Range:-135° to 00°F (-93° to 71°C) Silicone elastomers are made from silicone, xygen,

hydrogen, and carbon. They have poor tensile strength, tear resistance, and abrasion resistance. However, they have xcellent esistance o emperature xtremes, especially dry eat. ilicones re not esistant o e- troleum iquids, but re esistant o many of the synthetic liquids.

(15) Fluorosilicone FSi) Temperature Range:-80° o 350°F(-62° to + 176°C) Fluorosilicone rubbers are a recent development and

combine he ood xtreme emperature properties of silicone rubber with ue l nd il esistance.

3-6.2.2 Effect of Radiation on Elastomers, Plastics, an d esins

Seals, packings, and other similar components of hy - draulic systems that use elastomers, plastics, or resins are subject to damage from radiation. As these compo-

nents are usually the "weakest link" in the structure of a ystem, t s mportant o elect materials hat will provide the radiation resistance needed for a particular application. Data on the relative radiation resistance of elastomers, thermosetting resins, and thermoplastic resins are given in Figs. -57, -58, and 3-59 (Ref. 33).

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TABLE 3-20 .

COMPATIBILITY OF CO M M E RCI A L H Y D R A U LI C FLUIDS WITH ELASTOMERS

Dynamic nd

Hydraulic luid

Static Stat ic Only CD a CD

a

u 01 Ö 01

a -p w

CO

CO c 3m

0) H•H fn

-P •H S5

a o B CO o o SH O

ü•H

HO

i-i

-P

CD a CD

p< O

CD C C D •H T3 CO

-P

c O

HC O

a

CD c CD u p.O Ifl

H

C D C o CJ •H

H•H en o u o

CD

a o .C pCD fi

HO

FM

CD £>

§ PC

-p

CD C

OCJ

•H

H

<H CO

CD O Hcp

CO

H0

P-,

Phosphate Ester iquids: 1 4 4 4 4 2 4 4 4 4 3 4 4 3 kydrol 00 4

7000 1 4 4 2 4 1 4 4 4 4 3 4 4 3 4 Pydraul -9 2 4 4 1 4 2 4 4 4 4 2 4 4 2 X

150 1 4 4 1 4 2 4 4 4 4 2 4 4 2 X 625 2 4 4 1 4 2 4 4 4 4 2 4 4 2 X AC 2 4 4 1 4 2 4 4 4 4 2 4 4 2 X

FRYQUEL (Cellulube) 90,

100, 150, 220, 300, 500 1 4 4 1 ; 4 1 4 4 4 4 2 4 4 1 * Houghto-Safe, 1010, 1055,

1120 1 4 4 1 4 1 4 4 4 4 2 X 4 3 3

MIL-H-19457B 1 4 4 2 : 4 1 4 4 4 4 4 4 4 3 4

Halogen-Containing iquids: Aroclor 246 a hlorinated

biphenyl) 2 4 3 1 4 2 4 4 4 4 2 X 4 2 4 Pydraul -200 (chlorine-

containing romatic) 4 4 4 1 ; 4 4 4 4 4 2 4 4 2 X FC-43, FC-7 5 (perfluoro-

butyl mines) 1 4 1 2 X 1 1 X 1 X 2 X X 1 1

Silicate Ester iquids: OS-45 4 4 2 1 X 4 1 4 2 4 2 4 4 4 X Oronite 200, 8515 4 4 2 .1 X 4 1 4 G 4 1 1 4 4 X MLL-H-8446B 4 4 2 1 X 4 1 4 X 4 1 1 4 4 X

Silicone iquids: Dow orning 00, 510, F-60,

F-61 1 1 1 1 1 1 1 1 1 1 1 1 1 3 1 G.E. Versilube -50 1 1 1 1 1 1 1 1 1 1 1 1 1 3 2

Water ase:

(Water-Glycol olutions) UCON ydrolube 1 1 1 1 4 1 2 2 X X 2 4 X 1 X Houghto-Safe 71, 620 1 1 1 1 4 2 2 X X X 2 4 X 2 X

(Water-oil mulsions) Sunsafe 4 4 1 1 4 4 2 4 2 4 1 4 4 X X Shell ris 902 4 4 1 1 1 4 2 4 4 4 1 1 4 4 1

Mineral Oils: KIL-H-5606B 4 4 1 1 1 4 2 4 2 4 1 1 4 4 1 MIL-H-6083C 4 4 1 1 1 4 1 4 2 4 4 1 2 4 1 MIL-H-276014 4 4 1 1 1 4 2 4 X 4 2 X 4 3

i

X

Compatibility Rating : 1 a t i s f a c t o r y 2 a ir

3 o u b t f u l 4 n s a t i s f a c t o r y

|132

X Insufficient ata G Good

[From: Seal Compound Manual Used by permission of Parker Seal Company.]

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Damage

Incipient o ild

Mild to moderate

Moderate to evere

Incomplete data

Utility of Plastic

Nearly always usable

Often atisfactory

Limited use

Polyurethane Rubber

Natural Rubber

Adduct Rubbers

Styrene-butadiene SBA)

Viton-A

Poly BA

Cyanosilicone Rubber

Vinyl Pyridine Elastomer

Perylonitrile Rubber

Nitrile Rubber

Neoprene Rubber

Hypalon

Kel-F

Silicone Rubber

Polyacrylic Rubber

Butyl Rubber

Polysulfide Rubber

10°

m

E m m

mm

1

J_

—

*(measured against c a r b o n a s t h e absorpt ion m e d i u m )

_ L J 1 07 1 08 1 0

5

G a m m a Exposure D o s e , e r g s g1 ( C ) *

10 10

Fig. 3-57. Relative Radiation Resistance of Elastomers133

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Damage

Incipient o mild

Mild o moderate

Moderate o evere

Utility of Plastic

Nearly always usable

Often atisfactory

Limited use

Polystyrene

Polyvinyl carbazole

Acrylonitrile/butadiene/styrene ABS)

Polyimlde

Polyvinyl chloride

Polyethylene

Polyvinyl ormal

Polyvinylidene chloride

Polycarbonate

Ethylene propylene polyallomer

Kel-F

Polyvinyl butral

Cellulose acetate

Polymethyl alpha -chloroacrylate

Polymethyl methacrylate

Polyamide

Vinyl chloride-acetate

Teflon

L _L

*(measured gainst arbon as he bsorption edium)

_L

106

0'

0s

09

Gamma Exposure Dose, ergs g 1 ( C ) *

1 0 0 1 0 1 1 0 2

Fig. 3-59. Relative Radiation Resistance of Thermoplastic Resins133

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3-6.2.3 Test Methods fo r Elastomer-liquid Compatibility

The usual procedure fo r determining the compatibility of an elastomer with a particular liquid is to measure changes n arious properties of the lastomer fter immersion in the liquid. The most commonly used indicators of deterioration of an elastomer compound are excessive volume swell or shrinkage, a large decrease or increase of hardness, and an extreme change in tensile strength or elongation. Many of the changes (such as loss f hardness nd ensile trength) hat arious media cause in an elastomer compound cannot be considered deterioration of the ompound. Often uch changes are purely physical and the compound returns to its original state after removal from the media. Also , certain hanges, uch s swelling of rubber, re often required or atisfactory operation of the ystem. A l- most al l seal designs require a definite amount of swelling to effect a complete seal. Table 3-21 lists the rubber

swell requirements of several Military Specification hydraulic fluids.

Standard est procedures or various properties of elastomers an e ound n STM tandards Ref. 134). owever, wo eneral est methods av e been developed pecifically or he purpose of determining the effect of liquids on elastomers: (1 ) ASTM Test for

"Changes in Properties Resulting From Immersion in Liquids" (Ref. 35), and (2 ) Federal Test Methods fo r "Swelling of Synthetic Rubber" (Refs. 36, 37). These two est procedures re iscussed n he paragraphs which ollow.

(1 ) hanges n Properties of Elastomers Resulting from Immersion n Liquids

Test Method : ASTM D-471 Ref. 35) This method s ntended or se n stimating he

comparative ability of rubber and rubber-like compositions to withstand the effect of liquids by examination of the material fter removal from he iquid.

This method leaves the selection of test conditions of temperature nd im e o he arties nvolved, ut recommends he hoice of on e of eight est emperatures and on e of four test periods. Three specimens of the elastomeric material are immersed in the liquid in a test tube for the time and at the temperature specified. After mmersion, he pecimens re xamined or changes in weight, volume, tensile strength, elongation, and hardness. A ll changes are reported as a percentage of the original value.

(2 ) welling of Synthetic Rubbers Test Methods : Federal Test Method 3603 (Ref. 36)

Federal Test Method 60 4 (Ref. 37) These est ethods escribe rocedure or he

determination f he welling ffect f ubricants on synthetic ubber. ethod 603 s or etroleum

TABLE 3-21 .

R U B B ER SWELL R EQ U I R EM EN TS O F MILITARY SPECIFICATION H Y D R A U LI C FLUIDS

Military Specification Test Method or

Test Description Type of Rubber

Required Rubber Swell, %

Min M ax MIL-H-5606B Federal No. 3603.4* Standard L 19.0 28.0

MIL-H-6083C Federal No. 3603.4* Standard L 19.0 26.5

MIL-H-13866A 168hrat 158°F Standard L - 25.0

MIL-H-27601A 70hrat400°F Viton A or B 0 10.0

Phosphate Ester MIL-H-19457B

(SHIPS) Federai No. 3603.4* Butyl ±5%o

caused tricresj phospr

f swell by A

iate Silicate Ester MIL-H-8446B Federal No. 3603.4* Synthetic S 15.0 25.0

*Federal Test Method Standard No. 91a.

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products n eneral, nd Method 60 4 is for aircraft turbine ubricants. he asic procedures f the est methods, owever, re daptable o other products.

The volume of standardized test rubber sheets (1 in. X 2 in. X 0.075 in.) is determined by water displacement. The rubber sheets are then immersed in the specimen liquid fo r 68 hr at 58°F. The rubber sheets are then

removed, cleaned, and the volume again determined by water displacement. Any change in volume is presented as percent of the original olume.

3-6.3 COMPATIBILITY WITH COATINGS

Compatibility f hydraulic luids with paints nd other urface protection coatings is problem hat is often ignored in arly design stages. Although it may have been previously determined that a candidate hy - draulic luid s ompatible with he materials se d in the system, it is still necessary to determine compatibility with surface coatings it may contact. The number and ypes f oatings re any-painted, nodized, phosphatized, nitrided, nd lated.

3-6.3.1 Compatibility With Paints

Paints are probably the most common surface coatings ncountered. lthough paints re normally x- terior o he hydraulic ystem except n are ases where eservoirs or other omponents have heir n- terior urfaces painted), heir ompatibility with y- draulic fluids must be considered. Hydraulic fluids can come into contact'with painted surfaces from spillage during filling, from leaks, and from rupture of hydraulic ines.

Many of the ynthetic iquids av e oftening or stripping ction n aints hat re esistant o e- troleum ils nd uels. hosphate ster luids, ommonly se d n ommercial viation, ave arked stripping" action on conventional paints. Water-glycol solutions also have a softening and stripping action on many paint finishes. For these and other synthetic hydraulic luids, he ore esistant ynthetic inishes must be employed, .g., epoxy-resin paints. The effect of various types of hydraulic fluids on standard oi l and fuel resistant paints is summarized in Table 3-22. The

data presented n Table -2 2 re generalized nd n every case, compatibility of a particular paint should be checked with the candidate hydraulic fluid. Workers at the U.S. Army Coating and Chemical Laboratory have done research on the compatibility of various hydraulic fluids with Military Specification paints. The results of

some of this work are shown in Table 3-23. Hydraulic fluid manufacturers requently have proprietary data available on compatibility of their products with special paints or finishes and will supply the data to purchasers.

TABLE 3-22.

E FFE CT OF H Y D RA U L I C FLUIDS ON S TA N D A R D PAINTS*

Hyraulic Fluid Effect on Paints Type

Mineral Oils None Water-glycols Softens or strips Water-oil Emulsions None Chlorinated Aromatics Incompatible Phosphate Esters Incompatible Silicones Incompatible

*Standard paints are petroleum fuel- and oil-resistant.

The resistance of various types of paints to attack by chemical media is given n Table -24. The data re - sented in Table 3-24 are not directly applicable to hy - draulic fluids, but an e seful n determining what effect various contaminants or additives may have on the compatibility of hydraulic fluid with paints.

3-6.3.2 Compatibility With Other Coatings

The ompatibility of hydraulic luids with urface coatings other than paints is an area that ha s received very ittle attention. Other surface coatings would n- clude metal platings, nodizing, nitriding, nd phosphate finishing. There are essentially no data available on hese opics ither n he eneral iterature or n hydraulic fluid manufacturers' data heets.

The ack of data ould ead o he conclusion hat compatibility with these surface finishes is not a problem. However, because these finishes are either metallic or a chemical conversion of the base metal, the question is one that hould be considered n the determination of liquid-metal ompatibility.

3-6.4 COMPATIBILITY WITH OTHER LUBRICANTS

Compatibility of a hydraulic fluid with other lubricants it may contact must also be considered. Other lubricants include ubstitute hydraulic fluids, ubricating

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TABLE 3-23.

RESISTANCE O F MILITARY SPECIFICATION COATINGS TO H Y D R A U LI C FLUIDS*

Coating Specification

Title Liquids or Hydraulic Fluids

th e Coating Resists

MIL-L-19537A Lacquer, Acrylic-Nitrocellulose, for Aircraft Use)

Diester Lubricating Oils

MIL-L-19538B Lacquer, Acrylic-Nitrocellulose Camouflage (for Aircraft Use) (ASG)

MIL-L-7808G, Synthetic Base Lubri- cating Oil

MIL-C-22750B Coating, Epoxy-Polyamide Diester Lubricating Oils

MIL-P-22808A Paint, Epoxy, Hydraulic luid Resistant MIL-E-17111, Petroleum Base Power Transmission Fluid MIL-H-19457B, Phosphate Ester Fluids

MIL-P-23377B Primer Coating, Epoxy Polyamide Chemical an d Solvent Resistant

Diester Lubricating Oil

MIL-L-7146A

Lacquer, Hydraulic Fluid Resistant (for Interior Aircraft Use)

MIL-H-5606B, Petroleum Base Hydraulic Fluid MIL-H-22072 (AER), Water Base Hydraulic Fluid

*Data obtained in private communication with Dr. C.F. Pickett, Director, U.S. Army Coating and Chemical Laboratory, 26 Aug. 68.

oils, reases, nd olid ilm ubricants. Most hydraulic systems in operation today use components not lubricated y he ydraulic luid. or he ystem o operate satisfactorily, t is essential that the hydraulic fluid be compatible with any of these lubricants it may contact, ither accidentally or by design.

Compatibility of on e hydraulic fluid with another is a problem hat oe s not occur ften nd o t s re - quently forgotten. The problem is primarily of concern in eplacing ne hydraulic luid with nother. When nonadditive petroleum hydraulic luids were he only ones available, changing to another hydraulic fluid was an easy matter. However, he advent of extensive use of additives and the synthetic liquids made substitution of hydraulic luids virtually mpossible. Many of the synthetic fluids are completely incompatible with ne another or with petroleum fluids. Upon mixing, even in small ratios, they may form precipitates, gums, sludges, or gels. Water and oil emulsions are often compatible with mineral oil fluids in the sense that they will tend to absorb small amounts of the oil into the emulsion. Reduction of the ire etarding properties s he nly resulting harm. everal Military Specification hydraulic luids av e equirements hat hey e ompatible

with certain other fluids in the sense that they do not separate or form gums, precipitates, or gels. However, this equirement may av e he ffect of deactivating important additives or the loss or reduction of important properties.

There are no standard ASTM or Federal Test Meth- ods available for directly determining the compatibility of on e hydraulic fluid with another. Simple mixing tests with visual observation to determine separation, emulsification, ormation of solids, tc., re normally used to screen for compatibility. However, here are standard test methods to determine the compatibility of lubricating oils and solid film lubricants with hydraulic fluids. Two of them re iscussed n he paragraphs which ollow.

(1 ) ompatibility of Turbine Lubricating Oils

Test Method : Federal Test Method 3403 (Ref. 38) This method is used to determine the compatibility

of aircraft turbine lubricants with specific referee lubricants. Although the test procedure is designed for aircraft turbine lubricants, it can be used to test the compatibility of hydraulic luids with ny eferee iquid.

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TA BL E 3-24.

RE SI STA N CE OF PAINTS T O AT TA C K BY CHEMICAL MEDIA

Chemical Media

< <

CO

1 09

o •3 U

> >

§ a. W

u © 1

> Vin

Alk

11

Ch

o

n

ed

R

u

Salt Spray G-E E E E E- E E E E E

Alcohol Solvents F-G P P G G-E E G F G E

Gasoline G-E G P G E E E E E G

Hydrocarbon Solvents G-E F P F E E E - - -

Ester, Ketone Solvents P P P P G-E F P P P P

Chlorinated Solvents P P P P G-E F P P P P

Alkalis F-G F-G E P E P P E F- G E Mineral Acids P-G F- G F-G F-G G-E P- F E E G-E E

Oxidizing Acids P- F P- F - P P- G P- F P E P G

Organic Acids (Acetic, Formic) P P E P F-G P P G F-G F- G

Organic Acids (Oleic, Steric) F F P F E E F E E F

Phosphoric Acids P P E G-E G-E F F E F G

Water F-G E E G E E F E E E

P-Poor F-Fair G-Good E-Exce lent

[From: Materials Engineering, Materials Selector Issue 141 . Used by permission of Reinhold Publishing Corp.

Three mixtures of 2 00 ml are prepared with the test liquid and the referee liquid. Mixtures are of 20, 00,

, and 80 ml of referee fluid. The mixtures are agitated by vigorous shaking and then heated to 212°F for 68 hr. The mixtures are then cooled, gitated again, and centrifuged (at 60 0 to 70 0 relative centrifuge force) for 10 min. The amount of sediment, f any, s recorded. The est emperature nd ixture atios an e

changed o fit he type of fluid being tested. (2 ) Fluid Resistance of Dr y Solid Film Lubricants

Test Method : Federal Test Method 7001 Ref. 39) This method determines the esistance of dry solid

film ubricants o oss of adhesion fter xposure o

various fluids. A 0.0002 0.0005 in. hick film of the solid lubricant is sprayed on both sides of a 3 in . by 6 in . anodized aluminum panel and cured. Two test pa - nels with olid ilm ubricant re mmersed one-half their length n est luid t 3.5°F (23°C) for 24 r. The panels are then cleaned with naphtha and examined for softening, lifting, blistering, cracking, or peel- ing. A test of lubricant adhesion is made by pressing a

strip of masking ape n he dry ilm ubricant nd removing it apidly. The est luids isted n he procedure re ircraft

turbine il MIL-L-7808), tandard hydrocarbon est fluids (MIL-S-3136, Type II), aircraft engine lubricating oil(MIL-L-6082, grade 1100), aircraft reciprocating

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engine uel MIL-G-5572, rade 15/145), ircraft turbine and jet fuel (MIL-T-5624, JP-4) and petroleum base ydraulic luid MIL-H-5606B). he eneral procedure of the test method, however, is adaptable to an y luid esired.

3-6.5 COMPATIBILITY WITH DDITIVES

Liquids or luid ower systems may ontain dditives o mprove he iscosity ndex, o uppress he formation of foam and emulsions, to combat corrosion, etc. f the proper chemicals are no t used, on e additive may counteract the desired effects of another, or may react with nother o orm nsoluble ubstances hat could be more harmful than the original problem. Ad- ditives must remain soluble in the fluid at all exposed temperatures nd hould ot eact ith omponent parts or ontaminants. Chemicals must not e ndis- criminately ixed ith n il. ydraulic luid up- pliers hould e onsulted n pecial roblems. Addi- tives are discussed in greater detail in Chapter .

REFERENCES

1 . Viscosity", Lubrication 7, 1966). 2. STM Standards 1967, Designation D-2161-66,

Part 17, p. 757, Philadelphia, American Society for Testing Materials, 967.

3. . H . Zuidema, he Performance of Lubricat- in g Oil, Reinhold Publishing Corp., N. Y ., 1959.

4. oger . atton, ntroduction o ydraulic Fluids, Reinhold Publishing Corp., N. Y., 962.

5. STM Standards 1967, Designation D-445-65, Part 17, p. 84 , Philadelphia, American Society for Testing Materials, 967.

6. ederal Test Method Standard No . 91a, Test Method N o. 05.4.

7. ederal Test Method Standard No . 91a, Test Method No. 04.8.

8. STM Standards 1967, Designation D-88-56, Part 7, . 1, Philadelphia, American Society for Testing Materials, 967.


10. STM Standards 1967, Designation D-2161-66, Part 7, p. 757, Philadelphia, American Society for Testing Materials, 967.

11 . STM Standards 1967, Designation D-2162-64, p. 783, Philadelphia, American Society for Test- ing Materials, 967.

12. STM Standards 1967, Designation D-2515-66,

Part 7, p. 916, Philadelphia, American Society for Testing Materials, 967.

13 . STM Standards 1967, Designation D-341-43, Part 7, p. 60, Philadelphia, American Society for Testing Materials, 967.

14. ederal Test Method Standard No . 91a, Test Method No. 121 .1 .

15 . M. Murphy, J. B. Romans, nd W . A. Zis- man, Viscosities and Densities of Lubricating Fluids from-40° to 700°F", ASLE Transactions, 561 1949).


17. ederal Test Method Standard No . 91a, Test Method No. 111 .2 .


19 . . . owers nd . . urphy, tatus of Research n ubricants, riction, nd ear, NRL Report No. 6466, Naval Research Laboratory, Washington, D. C, 967.

20. . . itch, r., luid ower nd ontrol Systems, McGraw-Hill, nc., N.Y., 966.

21. ressure- Viscosity Report, Vols. and 2, Ameri- can ociety of Mechanical Engineers, . ., 1953.

22. . R. Wilson, Effect of Extreme Conditions on the Behavior of Lubricants and Fluids, AFML- TR-67-8, Part I, anuary 968.

23. .E . Klaus, E.J. Tewksbury, nd M. R. Fenske, Fluids, Lubricants, Fuels and Related Materials, ML-TDR-64-68, February 964.

24. .E . Klaus, E.J. Tewksbury, nd M . R. Fenske, Fluids, Lubricants, Fuels and Related Materials, AFML-TR-65-112, April 965.

25. .E . Klaus, E.J. Tewksbury, nd M . R. Fenske, Fluids, Lubricants, Fuels and Related Materials, AFML-TR-67-107, Part , March 967.

26. . E. Klaus and M. R. Fenske, "Some Viscosity Shear Characteristics of Lubricants", Lubrica- tion Engineering, 00 (March 955).

27. . J. Gironda, E. B. Essing, and Bernard Rubin,

A onic hear Method for Determination f Shear Breakdown on Hydraulic Fluids and Lu- bricating Oils, WADC-TR-55-62, March 955.

28. . W . Furby and R. . Stirton, Viscosity Sta- bility of Hydraulic Fluids", Applied Hydraulics and Pneumatics 2, 4 (1959).

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29. etermination f th e Shear Stability of Non- Newtonian iquids, STM pecial echnical Publication No. 82 , Philadelphia, 955.

30 . ederal Test Method Standard No . 91a, Test Method N o. 471.2.

31 . . . ainman nd . . ackenzie, The Characteristics nd Performance of Specifica-

tion MIL-H-5606 Hydraulic Fluid", ubrication Engineering, 34 (June 966). 32 . . L. LeMar, Effect of Several Ga s Atmospheres

on ydraulic Fluid Stability, IA echnical Report 67-1954, Rock Island Arsenal, Rock Is- land, llinois, 967.

33. ederal Test Method Standard No . 91a, Test Method 01.8.



36. ederal Test Method Standard No . 91a, Test Method N o. 03 .

37. ederal Test Method Standard No . 91a, Test Method N o. 04.

38. ederal Test Method Standard No . 9la, Test Method No. 02 .

39 . ederal Test Method Standard No . 91a, Test Method No. 103.6.

40 . STM Standards 1967, Designation D-92-66, Part 7, . 1, Philadelphia, American ociety for Testing Materials, 967.

41 . ederal Test Method Standard No . 91a, Test Method N o. 101.6.

42 . STM Standards 1967, esignation -56-64, Part 7, . , Philadelphia, American ociety for Testing Materials, 967.


44 . STM Standards 1967, Designation D-93-66, Part 7, . 7, Philadelphia, American ociety for Testing Materials, 967.

45 . IL-F-7100, Fluid, Hydraulic, Nonflammable, Aircraft, issued December 950, cancelled Feb- ruary 958.

46 . ire Resistance of Hydraulic Fluids, ASTM Spe-

cial

echnical

ublication

o.

06 ,

hiladelphia, 966. 47 . IL-H-19475 SHIPS), ydraulic Fluid, ire

Resistant. 48. IL-H-22072 AER), ydraulic luid,

Catapult.

49 . ederal Test Method Standard No . 91a, Test Method N o. 52 .


51 . . G. Zabetakis, A. G. Imhof, and F. W . Lang, Research on th e Flammability Characteristics of Aircraft Hydraulic

Fluids, WADC-TR-57-151,

Supplement , 958. 52 . . G. Zabetakis, G . S. Scott, A. G. Imhof, and

S. ambiris, esearch n he lammability Characteristics f Aircraft ydraulic luids, WADC-TR-57-151, Part I, 959.

53 . Fire Resistant Hydraulic Fluids", Lubrication, 161 December 962).

54 . Synthetic ubricant esearch", ubrication (November 959).

55 . . . damczak, . . enzing, nd . Schwenker, Eds., Proceedings of the AFML Hy- draulic Fluids Conference, AFML-TR-67-369, December 967.

56. . . Blake, . W. Edwards, nd W. C. Ham- man, igh emperature ydraulic luids, WADC 4-532, March 955.

57. . . Blake, . W . Edwards, W . C. Hamman, and T. Reichard, High Temperature Hydraulic Fluids, WADC 4-532, Part II, April 957.

58 . . D. Yeaple, Hydraulic and Pneumatic Power and Control, McGraw-Hill, nc., N.Y., 966.

59 . STM Standards 967, esignation -2251- 66T, art 7, . 80 , Philadelphia, American Society for Testing Materials, 967.

60. STM Standards 1967, Designation D-323-58, Part 17, p. 51 , Philadelphia, American Society for Testing Materials, 967.


62 . ederal Test Method Standard No . 91a, Test Method No. 53 .



65. ederal Test Method Standard No . 91a, Test Method No. 50 .

66. . E. Lewis and H. tern, Design of Hydraulic

Control ystems, cGraw-Hill, nc., .Y., 1962. 67 . . E. Klaus, Some Properties of Spec. MIL-O-

5606 Hydraulic Fluid at Elevated Temperatures, PRL Report 6.3, Pennsylvania State University, Pennsylvania, 953.

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68. . . ufifley, evelopment of High ensity Recoil Oil, IA eport 8-516, ock sland Arsenal, Rock sland, llinois, 958.

69 . . C. Muffley, Density versus Viscosity as it In- fluences the Action of a Recoil Mechanism, RIA Report 60-598, Rock Island Arsenal, Rock Is- land, llinois, 960.

70 . ederal Test Method Standard No. 91a, Test Method N o. 01.5.

71 . STM Standards 1967, Designation D-287-64, Part 7, p. 38 , Philadelphia, American Society for Testing Materials, 967.

72 . STM-IP etroleum easurement ables (American dition), hiladelphia, merican Society or Testing Materials, 967.


74 . STM Standards 1967, Designation D-941-55 , Part 17 , p. 317, Philadelphia, American Society for Testing Materials, 967.

75. STM Standards 1967, Designation D-1217-54 , Part 7, p. 435, Philadelphia, American Society for Testing Materials, 967.


77. hermal Properties of Petroleum Products, M.S. Bureau of Standards Miscellaneous Publication No. 7.

78. . . Leslie, "The Relation of Fluid Properties and igh emperature ydraulic erformance", ASLE Transactions 7, 80 1964).

79 . . A. Wright, "Prediction of Bulk Moduli and Pressure-Volume-Temperature ata or e- troleum ils", SLE ransactions 0, 49 (1967).

80 . . A . Tichy and W . O. Winer, A Correlation of Bulk Moduli nd -V-T Data or ilicone Fluids at Pressures up to 500,000 psig", ASLE Transactions 1, 33 8 1968).

81 . ire Resistant Hydraulic Fluids, Part 5, ub- chapter E, chedule 30 , U.S. Dept. of Interior, Bureau f ines, ittsburgh, ennsylvania (1965).

82 . . C. Muffley, Foaming Characteristics of Re- coil and Hydraulic Oils, RIA Report 5-1686, Rock sland rsenal, ock sland, llinois, 1955.


84. ederal es t ethod tandard o. 91a, Method N o. 201.5.

85. ederal est ethod tandard o. 91a, Method N o. 211.3.


87. ederal Test Method Standard No . 91a, Test Method No. 07.


89 . ederal Test Method Standard No . 91a, Test Method No. 459.

90 . ederal Test Method Standard No . 91a, Test Method 004.4.

91 . STM Standards 967, esignation -2273- 64T, art 7, . 31 , hiladelphia, American Society or Testing Materials, 967.

92 . riction, ear, nd ubrication: erms nd Definitions, Research Group on Wear of Engi- neering Materials, Organization or Economic Cooperation nd Development.



95 . ederal Test Method Standard No . 91a, Test Method N o. 812.

96 . STM Standards 969, esignation -2596- 67T, art 7, . 70 , hiladelphia, American Society or Testing Materials, 969.


98 . STM Standards 967, esignation -2266- 64T, Part 7, . 99 , Philadelphia, American

Society for

Testing Materials, 967.


100. STM Standards 967, esignation -2428- 66T, art 8, . 65 , Philadelphia, American Society for Testing Materials, 967.



103. STM Standards 1967, Designation D-1947-66, Part 17 , p. 703, Philadelphia, American Society for Testing Materials, 967.



106. . E. Hatton, Hydraulic Fluids for High Alti- tude-High Temperature Vehicles, Paper 660661,

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SAE-ASEM Meeting, L os Angeles, California, October 966.

107. H . Gisser, he Effects of Nuclear Radiation n Lubricants, Conference n Effects of Nuclear Radiation n aterials, Watertown rsenal, 1967.

108. R. . underson nd A. . art, ynthetic

Lubricants, Reinhold Publishing Corp., N.Y., 1962.

109. ASTM Standards 1967, esignation D-91-61, Part 7, . 8, Philadelphia, American Society for Testing Materials, 967.

110. ASTM Standards 1967, Designation D-482-63, Part 7, p. 95 , Philadelphia, American Society fo r Testing Materials, 967.

111. Federal Test Method Standard No . 91a, Test Method No. 02.6.

112. ASTM Standards 1967, Designation D-1500-64, Part 7, p. 564, Philadelphia, American Society for Testing Materials, 967.



115. Federal Test Method Standard No . 91a, Test Method N o. 001.9.

116. ASTM Standards 1967, Designation D-189-65, Part 17, p. 00 , Philadelphia, American Society for Testing Materials, 967.

117. Federal Test Method Standard No . 91a, Test

Method No. 002.6. 118. ASTM Standards 1967, Designation D-524-64,

Part 17, p. 201, Philadelphia, American Society fo r Testing Materials, 967.

119. Federal Test Method Standard No . 91a, Test Method N o. 308.5.

120. ASTM Standards 1967, Designation D-943-54, Part 7, p. 328, Philadelphia, American Society fo r Testing Materials, 967

121. Federal Test Method Standard No . 9la, Test Method No. 508.


123. Federal Test Method Standard No . 91a, Test Method No. 457.


125. H . H . Uhlig, orrosion Handbook, John Wiley and ons, N.Y., 948.

126. Federal Test Method Standard No . 91a, Test Method N o. 325.

127. ASTM Standards 1967, Designation D-l 30-65, Part 7, . 2, Philadelphia, American Society for Testing Materials, 967.



130. D. Godfrey nd N . W. Furby, Cavitation of Oils nd ydraulic luids", n: damczak, Benzing, Schwenker, Proceedings of th e AFML Hydraulic luids onference, FML-TR-67- 369, December 967.

131. J. . ippenger nd . . icks, ndustrial Hydraulics, McGraw-Hill, nc., N.Y., 962.

132. Seal ompound anual, atalog 5702, Parker Seal Co., Cleveland, Ohio, 967.

133. he Effect of Nuclear Radiation on Lubricants and Hydraulic Fluids, REIC Report No. 4, Bat- telle emorial nstitute, olumbus, hio, April 0, 955.

134. ASTM Standards 1967: Rubber; Carbon Black; Gaskets, Part 28, American Society for Testing Materials, Philadelphia, 967.

135. ASTM tandards 967, esignation -471,

Part 28, p. 268, Philadelphia, American Society for Testing Materials, 967. 136. Federal Test Method Standard No . 91a, Test

Method No. 603. 137. Federal Test Method Standard No . 91a, Test



Method No. 001. 140. Charles par, ydraulic luids nd heir

Applications, ASME Publication 64 WA/LUB- 14 .

141. Materials elector ssue,. Materials Engineer- ing, October 967.

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CHAPTER 4

TYPES OF HYDRAULIC FLUIDS

4-1 GENERAL

A s the use of hydraulics and fluid power systems has increased, he number nd ypes of hydraulic luids available have also increased. This chapter presents a description of several methods used to classify hydrau- licfluids. In addition, descriptions of the more common types of hydraulic luids re resented ith brief summary of specifications or ach ype of fluid nd

specification data sheets isting exact pecification e- quirements for every hydraulic fluid iscussed. These specification summaries and data sheets are presented at he end of the chapter.

4-2 CLASSIFICATION OF HYDRAULIC FLUIDS

A wide range of liquids is available for use in hydraulic systems, and it is desirable to employ a classification system to assist those using hydraulic fluids o determine if a liquid under consideration may function satisfactorily for a particular application. However, the task of selecting the most meaningful classification system is complicated by several factors. The areas of application of hydraulic ystems nd he ype.of equipment used have become so diverse that a classification useful in ne area of application has ittle or no meaning in another. n addition, the increasing number and types of hydraulic fluids available add to the complexity of the ask. n imple, ow performance hydraulic ystems, where operating parameters re not evere, l- most an y liquid-water, water-based liquids, natural pe - troleum products, or the more sophisticated synthetic liquids-may be used with varying degrees of satisfac- tion. In other areas, where the operating parameters are

very severe, nly limited number of liquids may be considered and selection must be made with considerable care. n addition, there are liquids which are used primarily for purposes other than s hydraulic fluids, but which av e properties permitting them o be employed for the latter purpose in many applications.

Because of he wide nd astly different reas of application, t s ot uprising hat ydraulic luids have been classified by many different systems based on their different characteristics such as physical properties, hemical ypes, operating apabilities, tility, or specific applications. Although none of these groupings fully describe the properties of a hydraulic fluid, hey are still employed and assist in selecting fluids for use in pecific areas.

4-2.1 CLASSIFICATION BY PHYSICAL PROPERTIES

A classification based on viscosity ranges was on e of the. earliest ethods se d ince petroleum roducts were the only hydraulic fluids widely used and viscosity was he most mportant property of this lass of hy - draulic luids. The iscosity method s ccepted nd used as a means of classifying petroleum base hydraulic fluids by he fluid manufacturers, he utomotive n- dustry, hydraulic omponent manufacturers, nd y- draulic system designers and builders. Hydraulic fluids grouped in this manner are generally specified as suitable or se n iven pplication within pecified viscosity range. However, in the case of nonpetroleum base synthetic fluids, a classification based on viscosity range alone is not sufficient because of the importance of other properties.

4-2.2 CLASSIFICATION BY CHEMICAL PROPERTIES

Chemical classification of hydraulic fluids is extensively se d y echnical ersonnel, uch s hemists and petroleum ngineers. hemical lassification s- sists them in predicting general characteristics of a new hydraulic fluid or in developing a new hydraulic fluid for a specific application. In chemical compounds such

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TABLE -1. C HAR AC TER ISTIC S OF HYDR AULIC FLUID BASE S TO CK S

V i s c o s i t y - Vo l a t i l i t y - Thermal O x i d a t i v e H y d r o l y t i c F i r e L u b r i c a t i n g A ddi t ive

F l u i d C lass t e m p e r a t u r e v i s c o s i t y S t a b i l i t y S t a b i l i t y S t a b i l i t y R e s i s t a n c e A b i l i t y R e s p o n s e

I . e t r o l e u m B a s e G P G F E P F E

II. o n p e t r o l e u m B a s e A. h o s p h a t e E s t e r s G F F G F E E G B. i l i c a t e E s t e r s E G E G F F G G C . a r b o x y l i c Acid E s t e r s G G F F G F G G D. o l y s i l o x a n e s E 3 G F E F P P E . lycols G G G G G F G F F . a s t o r Oils G G F F G F G G G. o l y o x y G l y c o l s G G n G G F G F H. a t e r G l y c o l s G P F G E E P G I . m u l s i o n s G P F G E . E P G

I I I . x p e r i m e n t a l an d P o t e n t i a l F l u i d s A. o l y s i l o x a n e s ( S i l a n e s ) F F E G E F F F B . y d r o c a r b o n s G G E F E P G G C . l u o r i n a t e d P o l y m e r s P P E E G E P P

D. o l y p h e n y l E t h e r s F G E G E F G G E. e t e r o c y c l i c S y n t h e t i c s - - G - - G - - F . h o s p h o n i t r i l a t e s F G W E W G E G G. iqu id M e t a l s G F G P P P F F

E x c e l l e n t G oodF ai r P oo r W ide R a n g e Va r i a b l e - ot D e f i n e d

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The MIL-SPEC equirements or ypical hosphate ester base hydraulic fluid are shown in the summary nd specification data sheets in par. -6 .

4-4.2 SILICATE ESTERS

This lass of hydraulic luids as many properties similar to the phosphate esters since both are esters of organic cids. he rincipal ifferences n he wo classes are in hydrolytic stability, lubricating characteristics, lammability, nd iscosity-temperature ela- tionships. In general, silicate esters have low volatility and excellent viscosity-temperature characteristics, but relatively oor ydrolytic tability. ne f he utstanding characteristics of this class of hydraulic fluids is ood hermal tability ombined with xcellent e- sponse to antioxidant dditives. ilicate esters possess only fair oxidation tability nd re similar to hydrocarbon hydraulic fluids in their susceptibility to attack by oxygen; however, it is relatively easy to improve this property with proper additives. The lubricating properties f silicate sters re nly air but ith are n selection of materials nd operating onditions, hese hydraulic luids will provide ome egree of lubrication. ilicate sters re enerally airly oo d olvents and, lthough hey o ot issolve many plastics or synthetic lastomers, hey end o harden most lastomers after prolonged xposure at levated emperatures. With proper dditives nd he ight operating conditions, some silicate ester hydraulic fluids operate satisfactorily or extended periods at emperatures up to 425°F.

In ddition o their use as hydraulic luids, ilicate esters are used as heat-transfer fluids, electronic equipment coolants, weapon lubricants, etc. because of their outstanding thermal stability and excellent response to antioxidants. A typical MIL-SPEC for a silicate ester aircraft hydraulic fluid is given in the summary and the specification data sheets in ar . -6.

4-4.3 ORGANIC ACID ESTERS

This class of liquids is employed principally as lubricants or as urbine ngines, nstrument ubricants, base stock for synthetic greases, nd, o limited extent, s ase tock or hydraulic luids. se s

hydraulic luid s enerally n pplications where n- gine ubricating oil s used o ctuate hydraulic units such as accessories attached to jet ngines.

Organic esters are produced in both monoester (single ester group) and diester (two ester groups per molecule) compounds. The monoesters have relatively good

lubricating properties. However, they allow fairly high wear because of low shear strength, high volatility, and susceptibility o xidative breakdown. For hese easons, he monoesters av e ittle or o pplications s hydraulic luids. n he ther and, he iesters have xcellent iscosity-temperature roperties, ow volatility, good lubricating characteristics, high chemi-

ca l olvency, ood dditive esponse, nd oo d y- drolytic stability. The diester ubricating film haracteristics an d oxidation stability are generally equal to or better han quivalent petroleum hydrocarbon luids. The principal restriction or limitation of organic ester liquids s hermal tability ince hey end o break down t emperatures above 00°F.

The IL-SPEC equirements or ypical rganic acid esters are given in the summary and data sheets in par. -6.

4-4.4 POLYSILOXANES

The ilicone iquids, s lass, ossess ery ood viscosity-temperature and mechanical properties, making them ttractive as base stocks for synthetic ubricants or as hydraulic luids. These iquids have been used as hydraulic fluids, either alone or as compounded hydraulic fluids. Other characteristics which make the silicone liquids ideal for hydraulic fluids under severe operating onditions re : 1) heir properties o not change appreciably under a wide range of temperature and tmospheric onditions, 2) hey av e ery ow volatility, (3) they are compatible with many construction aterials, 4) hey esist ermanent iscosity

change under severe mechanical stresses, 5) they re available in wide ange of viscosities, 6) hey have very good dielectric properties, (7) they have good oxidation resistance, nd (8) they have low chemical sol- vency properties. These liquids are also less flammable than petroleum ils of similar iscosities but do not resist gnition n many lammability ests. ignificant limitations f ilicone iquids re heir marginal u- bricity for ferrous materials in sliding contact and their high ompressibility. n eneral, he erviceable emperature of most silicone fluids ranges from well below -65° to above 400°F.

Summaries of Federal and MIL-SPEC requirements for

ypical ilicone luids nd ata

heets

or hese

specifications are in ar . -6.

4-4.5 GLYCOLS

This class of hydraulic fluids is frequently referred to by everal names ncluding olyglycols, polyalkylene

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glycols, and polyethers. These glycol or polyglycol liquids are used extensively as base stocks and as components for synthetic lubricants and hydraulic fluids such as air conditioner lubricants, eavy duty brake fluids, and components of fire-resistant water-base hydraulic fluids. These liquids are characterized by good lubricity and antiwear properties, high flash point, high viscosity indices up o 50), ide ange f iscosities, ow volatility and pour point, poor-to-fair high temperature oxidation properties, little effect on rubber and metals, and ery oo d olubility haracteristics nd dditive response. They have good resistance to sludge an d varnish formation, and excellent resistance to mechanical shear. The viscosity-temperature properties re qual to or better han imilar petroleum products. n eneral, he serviceable temperature range of these fluids is rom near 0° to above 00°F.

MIL-SPEC equirements or ypical lycol yp e hydraulic fluid are given in the summary and specification data sheets n ar . -6 .

4-4.6 CASTOR OILS

This lass of hydraulic luids s based n organic fatty ils similar to animal ils, ish oils, nd mineral oils. Because of their properties, they are seldom used alone asa lubricating oil or hydraulic fluid. The organic oils xidize, ausing umming, nd hey poil r become rancid, thus releasing free fatty acids. At high temperature, these oils tend to decompose to corrosive acids. These ils lso will upport bacteria nd are should be taken o keep hem terile. The addition of castor oil or other fatty

oils to petroleum

mineral

oils will increase the load-carrying ability. Some of the liquids ncorporating hese ils re team-cylinder ils, marine-engine ils, utting ils, utomatic-transmission fluids, hydraulic fluids, and industrial gear oils. In general, astor oils re moderately igh iscosity iquids with lash point bove 00°F and pour point above 0°F.

Summary nd data heets of several ypical MIL- SPEC requirements fo r compounded liquids containing castor oil re in ar . -6.

4-4.7 POLYOXYALKYLENE GLYCOLS

The polyoxyalkylene glycol class of hydraulic fluids have many of the same properties as the polyalkylene glycol liquids discussed in par. 4-4.5. In some cases, the polyoxyalkylene liquids have somewhat superior properties. ost of hese luids av e olyoxyethylene-

polyoxypropylene ase nd are characterized by high viscosity indexes, low pour points, good thermal stability, air-to-good oxidation tability, oo d water tolerance, good corrosion resistance, and compatibility with rubber nd ther materials n brake ystems. hese liquids are considered particularly useful as hydraulic fluids or utomotive brake ystems.

A summary of MIL-SPEC requirements fo r a brake fluid containing this class of liquid and a data sheet of specification properties are in ar . -6 .

4-4.8 WATER GLYCOLS

This class of hydraulic fluids is generally considered fire-resistant. t sually contains 5-60 percent water, a glycol, an d a water-soluble thickener to improve viscosity. Additives are also incorporated to improve anticorrosion, ntiwear, nd ubricity roperties. ince the ire-resistance properties of these iquids re e- pendent upon the water content, extended use at temperatures bove 50°F s ot ecommended. The iscosity of these iquids s airly ow , but with proper additives they may be used satisfactorily t fairly low operating temperatures in systems such as aircraft hy - draulic systems. Typical viscosity indices for these liquids re n he ange of 40 o 60. ecause of the corrosive nature of the water component of these liquids, proper additives must be used to make them compatible with most common construction materials such as teel, luminum, rass, nd opper. t s enerally no t oo d practice to use these liquids n contact with soft or sacrificial plated materials such as galvanizing or cadmium lating. Antiwear and ubricity additives can make hese iquids uitable or se n hydraulic systems an d machines at moderate pressures. However, at igh ressures or oads, ervice nd maintenance problems ncrease. he dditive-containing ater- glycol liquids generally are compatible with the various seal and packing materials used in systems designed for petroleum ype luids, but hese queous-base iquids tend to soften or lift many conventional paints or coatings. n general usage, it is a good practice to conduct periodic checks of water content of these liquids since the viscosity and other properties vary appreciably with the water content.

MIL-SPEC equirements for a typical water-glycol type ydraulic luid re iven n he ummary nd specification data sheets in ar. -6 .

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measure of the flammability of phosphate esters, is the spontaneous or autogenous ignition temperature which ranges from 00°F to more than ,100°F.

The third group, the triaryl phosphates, are the most viscous of the ertiary phosphate ompounds, have short liquid range, and are essentially water insoluble. This type of phosphate has a maximum recommended bulk operating emperature ange

etween 50° nd

200°F which s omewhat ower han he ryl hosphates. Their applications are mostly as compounding ingredients or synthetic hydraulic fluids.

The major dvantage of the phosphate sters s class of hydraulic fluids is their fire resistant properties combined with their ability to lubricate moving parts, especially teel n teel.

Some of the names of commercial liquids of the phosphate ester-type widely se d by industry re :

1 . kydrol 000 and 500A Monsanto hemical Company)

Both of these hydraulic fluids are fire-resistant phosphate esters containing small amounts of several additives (the 7000 and 00 designations refer to the fluid viscosity n entistokes t-40°F). hese luids ere developed or se n ransport ircraft hydraulic ystems. kydrol 00A has been adopted as the standard hydraulic luid y most of the world's airlines.

2. ydraul (Monsanto Chemical Company)

These liquids are a series of fire-resistant phosphate esters nd dditive-containing hydraulic luids eveloped or ndustrial achinery. ydraul ydraulic fluids are less expensive than Skydrol and are available in a range of viscosities to fit numerous industrial ap - plications. Pydraul A C , lthough produced primarily

as a fire-resistant lubricant for air compressor systems, may lso be used in certain hydraulic ystems.

3. RYQUEL Cellulube) Stauffer hemical Company)

These iquids re roup f ire-resistant riaryl phosphate ster ydraulic luids nd/or ubricants available in controlled viscosity ranges. The product or fluid numbers represent the fluid viscosity at 00°F in Saybolt Universal econds SUS). Products vailable include FRYQUEL 90 , 50, 220, 00 , 50, and ,000. Although these liquids function primarily as fire-resistant hydraulic fluids, hey also find applications as lubricants where fire resistance is ot equirement.

4. Houghto-Safe (E . . Houghton nd Company)

These products re also a series of phosphate ester fire-resistant ydraulic luids nd ubricants hich have properties and recommended usage similar to the Cellulube and Pydraul fluids. (The reader is reminded

that Houghto-Safe" s lso he name f lycol water fluid.)

5. ther Phosphate Ester Base Hydraulic Fluids and Lubricants

In ddition o hese ypical ommercial products, phosphate ster iquids re ompounded ith any different materials to produce ne w liquids fo r different

applications. om e of these liquids re compounds of several types of phosphate esters and additives; others are ompounds of phosphate sters nd other iquids such as chlorinated silicone liquids. In general, the purpose of these developmental oils is to improve or extend the operating temperature limits and the range of certain characteristics such as lubricity, antiseize, and viscosity ndex.

4-5.2.2 Halogenated Compounds

4-5.2.2.1 Polysiloxanes Silanes)

These compounds re silicone-containing materials being investigated fo r applications as hydraulic fluids. These liquids have molecular structures which contain only ilicon-to-carbon onds nd o ilicon-oxygen bonds s o ther ilicones nd ilicate sters. he molecular organic radical of these fluids may be paraf- finic or aromatic hydrocarbons with mixtures of alkyl, aryl, lkaryl, or arylalkyl groups present.

In eneral, hese iquids av e poor ubricity nd \ narrow iscosity ange. om e dditives av e hown promise f mproving elected haracteristics; om e polymers are effective in increasing the viscosity; tricresyl phosphate and sodium petroleum sulfonate both ac t as ntiwear dditives, nd odium nd otassium amides re ffective s ntioxidants. ecause of u- perior thermal stability and chemical inertness, the silanes appear to be a promising base stock for hydraulic fluids for se in he temperature ange of 0° o more than 700°F. Typical properties of silane fluids are pour point,-25°F; flash point, above 500°F; bulk density, 7.4 lb/gal; nd iscosity, 7 St t 00°F.

4-5.2.2.2 Hydrocarbons

The halogenated hydrocarbon liquids possess several properties that make them attractive for use as hydraulic fluids. They have outstanding fire resistance, oo d thermal tability nd eat-transfer haracteristics, good oxidative stability, and boundary-lubrication activity. owever, hey o av e ome eficiencies, .e.,

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poor viscosity-temperature properties nd high reezing point.

Some of the commercial hydrocarbon liquids usable as hydraulic fluids and/or lubricating fluids re :

(1 ) roclor (Monsanto Chemical Company) Aroclor luids re eries of hydrocarbon iquids

containing hlorinated iphenyls nd over ide

range of viscosities. These fluids av e xcellent shear resistance, re hermally nd hemically table, noncorrosive, and provide a high degree of extreme pressure lubricity.

(2 ) el-F Fluids (Halocarbon Corporation) The Kel-F fluids are a series of wide range hydrocar-

bon hydraulic fluids and oils containing halofluorocarbon oils. These fluids are fire-resistant, chemically and thermally stable, nd may e used in mechanisms associated with reactive chemicals. The Kel-F fluids have extreme esistance o breakdown, nd xcellent low and load-bearing characteristics. In addition to hydraulic fluid applications, hey are also employed as com-

pressor lubricants. (3 ) luorolube (Hooker Chemical Company)

The Fluorolube luids re eries of hydrocarbon compounded liquids of similar composition, properties, and sage as the Kel-F fluids.

and are marginal lubricants. Their operating temperature range is room temperature to near ,000°F. How- ever, heir main deterrent s heir eficiency n ow - temperature characteristics.

4-5.2.4 Heterocyclic Compounds

Several heterocyclic ompounds have een nvestigated fo r applications as synthetic hydraulic fluids and lubricants. The most promising are those compounds containing itrogen, hich ho w hermal tability above 00°F o round ,200°F. ther eterocyclic compounds re ess table. t he present ime, o commercial luids of this class are available.

4-5.2.5 Phosphonitrilates

These liquids are being investigated as intermediate temperature ange hydraulic luids nd lso s ubricants. Generally, they are stable to hydrolysis and resist thermal polymerization up to 750°F. These liquids are still classed as research items and no commerical fluids are available.

4-5.2.6 Liquid Metals

4-5.2.2.3 Perfluorinated Polymers

The perfluorinated polymers re table, igh-temperature liquids capable of use in he range of—50° to +

700°F hat

o not

orm

ludge or ar

ven

n he

presence of air. These liquids have excellent flow characteristics, outstanding thermal and chemical stability, generally good corrosion characteristics, and are compatible with most metals and seal materials. A typical commercial fluid of this type is Krytox 43 E. . du Pont e emours nd ompany). erfluorinated polymers re orrosive ith ertain etals bove 500°F, and provide little or no protection against rusting of ferrous metals at elatively high humidities.

4-5.2.3 Polyphenyl Ethers

This class of liquids has been proposed fo r use as a high-temperature ydraulic luid nd onsiderable investigation has been conducted in this direction. Gen- erally, hese iquids have oo d oxidation tability, do not ydrolyze, esist ecomposition rom adiation,

Liquid metals have some possible usage as hydraulic fluids fo r special applications at very high temperatures (to ,500°F). The liquid metal which ha s been investigated ost, dentified s AK-77, s ixture f sodium and potassium. This liquid is silvery in appearance similar o mercury), nd ighly eactive ith oxygen o hat t must e se d n losed xygen-free systems. The mixture melts at about 0°F, atomizes in air at room temperature, and ignites spontaneously in air at 39°F. f water is present, NAK-77 eacts io- lently, releasing hydrogen and heat sufficient to ignite both he hydrogen and he NAK-77 f any oxygen s present. Surface tension is about twice that of water and its specific gravity is slightly less than water. Viscosity is about 0.50 cS t at 15°F and the friction coefficient is high, bout 0 times that of light il.

Handling nd sage of iquid metals re ifficult since the hydraulic system must be hermetically sealed and contain an inert gas. If NAK-77 burns, it is nonex- plosive unless water is present, but the fumes are toxic.

In ddition o NAK-77, ther iquid metals av e been nvestigated xperimentally ut hey enerally have higher melting points and similar hazardous operating characteristics so that liquid metals seem to offer only imited usage fo r very special pplications.

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4-6

YDRAULIC FLUID A ND LUBRICANT SPECIFICATIONS

The ollowing ages ontain nformation n he specifications for hydraulic fluids and lubricants mentioned in preceding paragraphs. For each iquid, data presented are: (a) a Specification Summary Sheet; and

(b ) pecification roperty equirements heet. he specifications are presented n he following order:

1 . etroleum Base Liquids: VV-L-800 MIL-L-2104B MIL-H-5606B MIL-H-6083C MIS-10137 MIS-10150 MIL-L-10295A MIL-H-13866B(MR) MIL-H-13919B

MIL-F-17111(NORD) MIL-L-17331F(SHIPS), Amendment MIL-L-17672B MIL-L-21260A MIL-F-25598(USAF) MIL-H-27601A(USAF) MIL-L-45199A MIL-H-46001A MIL-L-46002(ORD) MIL-L-46004(ORD) MIL-H-81019(WEP)

2. hosphate ster iquids: IL-H-19457B (SHIPS)

3. ilicate Ester Liquids: MIL-H-8446B 4. rganic Acid Ester Liquids: MIL-6085A; MIL-

L-7808G; MIL-L-23699A 5. olysiloxane iquids: IL-S-81087A(ASG);

VV-D-001078 GSA-FSS)

6. lycol Liquids: MIL-H-5559A(WEPS) 7. astor il s iquids: IL-P-46046A(MR);

JAN-F-461 8. olyoxyalkylene lycol iquids: IL-H-

1391 OB; VV-B-680a 9. ater Glycol Liquids: MIL-H-22072A(WP) The code assigned to the abbreviations fo r military

activities listed as he custodians of a specification s: Army-MR: U.S. Army Materials Research Agency

Watertown, Massachusetts 02172 Army-GL: U.S. Army Natick Laboratories

Natick, Massachusetts 07162 Navy-SH: Naval hip Engineering Center

Washington, D.C. 0360

Navy-WP: Naval Air Systems Command AS) Washington, D.C. 0360

Navy-SA:

aval upply ystems Command Headquarters Washington, D.C. 0360

Navy-YD:

aval acilities Engineering Headquarters Command

Washington, D.C. 0360 Air orce-11: Systems Engineering Group (AFSC, EP) Wright-Patterson AFB, Ohio 45433

Air Force-67: iddletown Air Material Area (MAAMA, MANSS) Olmsted AFB, Pennsylvania 7057

VV-L-800:

UBRICA TING OIL, GENERAL PUR - POSE, RESERVATIVE WATER- DISPLA CING, LOW TEMPERA TÜRE)

(NATO Symbol: 0-190)

a. eneral characteristics: This pecification ov - ers a general purpose, water-displacing, lubricating oil fo r low-temperature applications. It has a pour point of -70°For lower and a viscosity of 7,000 cS t t 40°F.

b. sable emperatures: The perating emperature range is ot pecified.

c. hemical omposition: his iquid s e- troleum base oil containing additives necessary to meet specification requirements. Principal requirements are for corrosion, oxidation nd water displacing properties.

d. ses: This liquid is a lubricating oil for protection against corrosion of small arms, automatic weap- ons, uz e mechanisms, eneral squirt-can applications and whenever a general purpose, water-displacing, low temperature, ubricating oil s equired.

e. imitations: This iquid oses ts ewtonian properties at temperatures below -40°F, snould not be used on aircraft equipment such as guns when operation at -65°F is required.Very low-temperature applications should be established by ests.

f. ustodian: Army-MR

MIL-L-2104B: UBRICATING IL , NTERNAL COMBUSTION ENGINE HEAVY

DUTY) (NATO Symbol: None) a. eneral characteristics: This specification ov -

ers multi-grade, detergent-type, petroleum ase il which ay ontain dditives o eet pecification equirements.

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VV-L-800: L U B R I C AT I N G OIL, GENERAL PURPOSE, PRESERVATIVE (WATER-DISPLACING, LO W TEMPERATURE)

PROPERTIES VALUES

Co lo r : No . (Max ) (ASTM) S p e c i f i c G r a v i t y : NR Pour Po in t , °F ; ( M a x ) : - 7 0

F l a s h Po in t , ° F; ( M i n ) : 275 Vi s c o s i t y, cS t : -6 5 °F (Max ) 60,000

-4 0 °F (Max ) 7 ,000 100°F (Min ) 1 2

Neutralization H o . : g K O H / g (Max ) R e p o r t A d d i t i v e s : n t i w e a r ( t r i c r e s y l p h o s p h a t e ) ; $ w t As R e q ' d a n d Approved

Ox id . I n h i b i t o r s , w t As Req_'d a nd Approved

Po u r Poin t D e p r e s s a n t , $ wt As Req.'d a nd Approved Vi s c o s i t y I m p r o v e r s $ w t As Req/d a n d Approved O t h e r s As R e q ' d a n d Approved

P r e c i p i t a t i o n No. . 0.05 Water C o n t e n t : $ (Max ) - - Co rr. a nd Oxid. S t a b i l i t y : t e e l + 0 . 2 0

168 h r at 2 5 0 ° F Aluminum Alloy ± 0 . 2 0

Max w t C h g , m g / c m Magnesium A l l o y +0 .2 0

Cad . -Pla te ± 0 .2 0

Coppe r +0 .2 0

Pi t t in g , Etch a n d C o r r. a t 20X N o n e $ V is Ch g at 100°F -5 to + 20 N e u t r a l . No . I n c r e a s e (Max) 0 .2 0

I n s o l u b l e M a t ' l o r G u m m i n g ;

$ wt N o n e C o p p e r C o r r. : 72 hr at 2 1 2 °F No . 3 (ASTM) Low Te m p e r a t u r e S t a b i l i t y : 2 hr at -65°F No S o l i d s , n o n g e l R u b b e r Swel l : Ty p e L , V ol Chg; $ Solid P a r t i c l e C o n t e n t : 5 -1 5 M i c r o n s —

(Max P a r t s / 1 0 0 m l ) 16-25 M i c r o n s - - 26-50 M i c r o n s - - 51 100 M i c r o n s —

O v e r 10 0 M i c r o n s — E v a p o r a t i o n : 4 h r at 150°F — C o r r o s i v i t y : r a s s - s t e e l , 10 d a y s , 7 5 °F, 5 0$ R . H . No C o r r o s i o n Recommended Te m p e r a t u r e Ran g e , ° F: > -4 0 NATO S y m b o l : 0-190 S t o r a g e S t a b i l i t y : - - C o m p a t i b i l i t y : — Water S t a b i l i t y : 1 h r a t 77°F, 5 0$ R . H . No C o r r o s i o n Humidity Cab in e t : d a y s , 95-100$ R. H. T h r e e 1. 0 mm d o t s Machine Gu n Te s t ; -75°F, 25 R o u n d s No S t o p p a g e

N o t e s : R, no r e q u i r e m e n t s .

—, no i n f o r m a t i o n . U s e : G e n e r a l p u r p o s e w a t e r d i s p l a c i n g l ub at l o w t e m p e r a t u r e , c o r r o s i o n protection f o r

s m a l l a r m s a n d a u t o m a t i c w e a p o n s .

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MIL-L-2104B: LUBRICATING IL, INTERNAL OMBUSTION NGINE (HEAVY UTY)

PROPERTIES VALUES

Color: NR Specific Gravity: NR Pour Point, °F Max): Grade 10 -20

Grade 30 0 Grade 0 + 15

Stable Pour Point, °F Max): Grade 10 (cnly) -20 Flash oint, °F Min): Grade 10 360

Grade 30 390 Grade 0 400

Viscosity, cSt: 0°F; Grade 10 (Max) 2614

0°F; Grade 30 Max) 43,570 0°F; Grade 0 (Max) NR 210°F; Grade 10 5.44- 7.29 210°F; Grade 30 9.65-12.98210°F; Grade 0 16.83-22.7

Additives: Allowed Ho rerefined) Oxid. Characteristics: (ferrous and onferrous ngine

parts) No Corrosion Low emperature Deposit: 180 r low emp ycle Slight Corrosion Ring Stick: 120 r ngine test Nonstick, in ear Light-load eposit accumulation: 120 r engine est Minimize DepositFoaming: 75°F, after .0 in lowing, ml Max) No limit

75°F, after 10.0 in ettling, ml Max) 300 200°F after .0 in lowing, ml (Max) No limit 200°F after 10.0 in ettling, ml Max) 25 Repeat 75°F Test Same as init . 75°F est

Oil Additive Stability: No additive instability Storage Stability: Remain omogeneous Compatibility: All oils to Spec Recommended Temperature Range, °F : Above -10 NATO Symbol: None

Water Content:

Notes: NR, no equirements. --, no information.

Use: Heavy uty ngine oil or ecripocating ngines, etc.

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b. sable emperatures: The operating emperature ange s ot pecified, ut se bove 10°F is recommended.

c. hemical omposition: his iquid s e- troleum base oi l which may contain antifoam and pour point epressant dditives, s well s orrosion nd oxidation inhibitors to meet specification requirements.

It hall not ontain ny e-refined components. d. ses: This liquid is fo r crankcase lubrication of

reciprocating nternal ombustion ngines f oth spark-ignition nd ombustion-ignition ypes he n ambient emperatures are above -10°F.

e. imitations.This liquid is no t recommended for gear ox pplications ithout rior erformance evaluation. For highly supercharged compression-ignition engines operating at output levels of 150 ps i brake mean effective pressure or above, t may be necessary to decrease oil drain periods or change to oils supplied under MIL-L-45199 A and specifically intended for this service. This liquid shall be compatible with other oils qualified to this specification and shall have good storage ife when tored n losed ontainers t ormal emperatures.

f. ustodians: Army-MR Navy-SH Air orce-11

MIL-H-5606B: HYDRA ULICFL UID, PETROLEUM BASE; AIRCRAFT, MISSILE, AND ORDNANCE

(NATO Symbol: H-515) a. eneral characteristics: This pecification ov -

ers a petroleum ase ydraulic luid or ow ern - persture pplications. t s ye d ed or dentifica- tion purposes.

b. sable temperatures: The recommended operating temperature ranges are -65° to 160°F in open systems and 65° to 75°F in losed systems.

c. hemical omposition: his iquid s e- troleum base oil with the following additives: viscosity index improver, oxidation inhibitor, and TCP antiwear agent. The finished iquid must ot ontain any pour point depressants.

d. ses: The primary se s or his iquid nclude aircraft ydraulic ystem, utomatic ilots, hock

struts, brakes and flap control mechanisms. t is also used in missile hydraulic servo-controlled systems and ordnance ydraulic ystems sing ynthetic eal-

ing materials. e. imitations: Since his aterial as ather

high ate of evaporation, t hould not e se d s general purpose igh temperature lubricant or n

"open" hydraulic ystem nless the eservoir is filled frequently. t is most effective in closed-system" y- draulic units. t is no t interchangeable with an y other types of hydraulic luid,

f. Custodians: Army-MR Navy-WP Air orce-11

MIL-H-6083C: HYDRA ULICFL UIDS, PETROLEUM BASE, OR RESERVATION AND TESTING

(NATO Symbol: C-635) a. eneral haracteristics: his iquid s e-

troleum ase orrosion reservative or ydraulic equipment. The finished product shall have no deleteri- ous ffect n ressure-seal acking se d n ircraft hydraulic systems and hock struts.

b. sable emperatures: The perating emperature ange is 65° to +160°F.

c. hemical composition:The finished liquid shall be a petroleum base oil with additives to provide corrosion protection and to improve the viscosity/temperature haracteristics nd esistance o xidation. o pour point depressant dditive is allowed.

d. ses: This fluid is intended as a preservative oil in aircraft and ordnance hydraulic systems during shipment nd torage, nd lso s esting nd lushing liquid or hydraulic ystem omponents. t s not n- tended s n operational hydraulic luid, but may e used for limited operational se .

e. imitations: Not ecommended or igh emperature use or fo r heavy duty requirements. This liquid is no t interchangeable with Hydraulic Fluid, Castor O il ase, pecification IL-H-7644(USAF) r y- draulic luid, onpetroleum ase, utomotive, Specification VV-B-680a.

f. ustodians: Army-MR Navy-SA Air Force-11

MIS-10137: YDRAULIC LUID, PETROLEUM BASE, NTERMEDIATE VISCOSITY

(NATO ymbol: None) a. eneral characteristics: This hydraulic fluid is a

petroleum base liquid containing additives for moder-

ate temperature ranges. t s dyed dark green or dark blue fo r identification purposes.

b. sable emperatures: The operating emperature range is ot pecified.

c. hemical composition: This iquid s efined petroleum ase iquid with dditive materials o m- prove oxidation esistance nd viscosity-temperature

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MIL-H-6083C: HYDRAULIC FLUID, PETROLEUM ASE, FO R RESERVATION ND ESTING

PROPERTIES VALUES

Color: Red Clear) Pour oint, °F Max): -75 Flash oint, °F Min): 200 Viscosity, cSt: -65°F Max) 3500

-40°F Max) 800 130°F Min) 10

Additives: Antiwear; $ t 0.50 Oxidation nhibitors, $ t S .00 Corrosion nhibitors, $ t Allowed Viscosity mprovers, % t 10.0 Others No our oint ep.

Neutralization No.: mg OH/g Max) 0.20 Precipitation No.: (Max) 0 Evaporation: 4 r t 150° F NR Corr. and xid. Stability: Steel +0.20

168 r t 50°F, Aluminum Alloy +0.20 M ax t hg, Magnesium ±0.20

mg/cm^ Cad.-Plate ±0.20 Copper +O.60 Pitting, Etch, or orr. at 0X None Vise. Chg t 30°F, » -50 to +20 Neutral. No. Chg Max) 0.30

Solid Particle ontent: 5-15 Microns 2500

(Max art/100 ml) 16-25 Microns 1,000 26-50 Microns 250 51-100 Microns 25

Over 00 Microns 5 Copper trip Corr.: 72 r t 50°F Max) No. 3 (ASTM) L ow Temp Stability: 72 r t -65°F No olids, nongel Rubber well: Type "L" Vol hg, j, 19-26.5Foaming: (75°F) After 5.0 in lowing, ml (Max) 65

After 0.0 in settling, ml Max) Complete collapse Storage tability: 75°F, onths (Min) ±u\

Water ontent:% Max) 0.05Recommended Temp ange °F: Air -65/160 Specific Gravity: r N E hear tability: Vise hg; cSt/l30°F Max) 15,000 ump ycle; est (30 min onic Oscil.) Vise Chg; cSt/-40°F Max) \< L Ref. fluid, MIL-F-5602]

Neutral. No. Chg Max) ^ - +0,30 J NATO ymbol/interchangeable yd. Fluid: C-635/See Note Corr. Prot. (bare steel): 100 r t 20°F, 100$ .H. Trace

Notes: NR , no requirements. Not interchangeable with astor oil r onpetroleum ase oils.

Use: Preservative oil or rd. and ircraft systems, test r flush.

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characteristics, nd ricresyl hosphate or ntiwear properties. The liquid may also beprepared byblending equal quantities of fluids on the qualified products list of MIL-H-5606 and MIL-H-46004.

d. ses: This hydraulic fluid is for guided missile hydraulic ystems uch s he IKE ERCULES Missile System t ntermediate temperatures.

e. imitations: This iquid hall ontain o pour point depressants, admixtures of resins, rubber, soaps, gums, fatty oils, oxidized hydrocarbons or other additives unless specifically approved. t as a storage life of 2 onths nder ormal onditions -70° to + 120°F).

f. ustodian: U.S. Army Missile Command Redstone Arsenal, Alabama 5809

MIS-10150: YDRAULIC LUID, ETROLEUM BASE, OW EMPERATURE, COR- ROSION PREVENTING

(NATO Symbol: None) a. eneral haracteristics: his iquid s e-

troleum as e hydraulic luid ontaining dditives or use in aircraft, missile, and ordnance hydraulic systems in he ow emperature ange. t as pour point of -90°Fand viscosity of 80 0 cS t t 65°F.

b. sable emperatures: The perating emperature range is not specified, but the liquid is generally for very low temperature applications (to -90°F)and moderate high emperatures (less han + 200°F).

c. hemical composition: The finished iquid s clear and transparent petroleumbasefluid with polymeric additives o mprove viscosity-temperature characteristics, nd other dditives o nhibit oxidation nd corrosion nd o mprove antiwear properties.

d. ses: This hydraulic fluid is intended for use in automatic pilots, shock absorbers, brakes, flap-control mechanisms, issile ydraulic ervo-controlled ystems, and other hydraulic systems using synthetic sealing materials.

e. imitations: This hydraulic fluid is not for high temperature pplications, nd s not nterchangeable with ny other hydraulic luid xcept s pecified n equipment Technical Manuals. It ha s a normal storage life of 2 months.

f. ustodian: U.S. Army Missile Command Redstone Arsenal, Alabama 5809 (ERR MI-56001)

MIL-L-10295A: LUBRICATING IL, INTERNAL COMBUSTIONENGINE, SUB-ZERO

(NATO ymbol: None; Product ymbol: OES)

a. eneral characteristics: This pecification ov - ers a light duty, low viscosity oil with suitable additives to eet pecification equirements or ow mbient temperatures.

b. sable temperatures: This liquid is intended for use at mbient emperatures rom -65° to 0°F.

c. hemical omposition: his iquid s e- troleum base oil, or a synthetically prepared product, or combination thereof, with suitable additives to meetthe requirements of this specification including foaming, xidation, ing tick nd wear ests, s el l s viscosity ange, lash, pour point, tc.

d. ses: This liquid is used for crankcase lubrication f eciprocating nternal ombustion ngines t very low ambient temperatures, and other applications where a light duty nonoxidizing and nondeposit-forming oil is required.

e. imitations:Th\s liquid is not fo r high temperature or eavy duty pplications. This iquid s o e compatible with all engine oils previously qualified to this specification. t ha s good storage life when stored in losed containers at normal temperatures.

f. ustodians: Army-MR Navy-SH Air orce-11

MIL-H-13866B(MR): HYDRAULIC FLUID, PETRO- LEUM ASE, ARTILLERY RECOIL, SPECIAL

(NATO Symbol: None) a eneral characteristics: This hydraulic luid s

on e grade of special ecoil hydraulic luid or hock load mechanisms. The iquid s clear and transparent

and s dyed green for identification urposes. b. sable emperatures: The sable emperature

range s ot pecified, but s enerally imited o e- tween 30° and 200°F.

c. hemical composition: The finished liquid base is a refined mineral oil-free from resin, soap, unrefined oils, nd njurious ngredients which may ffect he proper function of the fluid. Viscosity index improvers, oxidation nhibitors, nd ther dditives-within e- fined limits-may be added if needed to meet specification equirements.

d. ses: This hydraulic fluid is primarily for ordnance equipment uch s hydrosprings nd ydro - pneumatic rtillery ecoil echanisms. t may lso be used in other fluid or force damping mechanisms.

e. imitations: This hydraulic fluid is not suitable for extreme temperatures; the fluid, and an y of its components, must not be subjected to temperatures above 300°F during blending or subsequent operation.


4-17

8/11/2019 884519


AMCP 706-123

MIS-10150: HYDRAULIC FLUID, PETROLEUMBASF, LOW TEMPERA TU B E , CORROSION PREVENTING

PROPERTIES VALUES

Color: Speci f i c Gravi ty: Pour Point , ° F (Max): Flash Point , ° F (Min): Viscos i ty, c S t : - 9 0 ° (Max)

( M a x ) . (Max) (Max) (Min) (Min)

Neutra l iza t ion N o . Additives: $ wt ;

' F -80°F -65°F -40 ° F 1 3 0 ° F 210 ° F

a g KOH/g (Max) A n t i - w e a r ( t r i c r e s y l phosphate) Oxidat ion Inhib i tor Corrosion Inhibitor Vi s co s i t y Improver

Corr. an d Oxid. Stabil i ty: Steel 168 hr at 250°F

luminum Alloy

Ma x wt C h g , agnesium Alloy m g / cm 2 ad.-Plate

Copper ? o Vise Ch g at 130 F

Pitt ing, Etch o r Corr. at 20X Increase i n Neutral . N o . ( M a x ) Insoluble Mat'l o r Gumming

Lo w Tem p era t u re Stabil i ty: 72 h r at -65°F Shear Stabil i ty: Viscosi ty Ch g at 130°F (Max) ( 3 0 m in onic osc i l . ) Viscosi ty Ch g at -40°F (Max)

Neutral . No. Ch g (Max) Evaporation: 4 h r at 150°F Copper Strip . Corr.: 7 2 hr at 250°F (Max) Solid Par t ic le Content : 5-15 Micron

(Max Part s / l00 ml ) 16-25 Micron 26-50 Micron

51-100 Micron Over 100 Micron

Foaming: (75°F) fter 5 .0 m in b lowing; m l (Max) af ter 10,0 m in sett l ing; m l (Max)

Rubber Swell : Type L , Vo l Chg, $ Water Content : Max) Storage Stabil i ty: (-80°to 120°F) Months (Min) Recommended Temperature Range ° F : Compatibility Hy d Flu ids: (Emergency Only) NATO Symbol: Corr. Inhib. (humidi ty) : 20 hr at 72°F (bare steel) Corrosiv i ty (b ras s an d steel): 1 0 days at 80°F We a r (Steel): Shell 4-ball ; ( 2 hr , 167°F,

40 k g 1,200 rp m ) Scar Di a

Notes: H R , no requi rements . - - , no in format ion .

Use: uto-p i lo t s , s h o ck absorbers , brakes , f l ap-cont ro l mech . an d other sys tems using synthet ic sea l s .

0. ]

Clear an d Transparent NR

-90 200

80 0 200

5 2. 5 0.20 0. 5 +

£ 2.0 A s Req 'd an d Approved

£ 10.0 +0.20 ±0.20 +0.20 +0.20 +0.60 - 5 t o +20

None 0.20

None No Solids, nongel < Ref. Fluid < Ref. Fluid

s 0.20 Oily, nontacky

H o . 2 (ASTM) 2,500

1,000 25 0

25 None

65 None

19-28 0.08

1 2 Lo w Tem p era t u re None None

No Corros ion No Corros ion

< 1 . 0

missi le hyd. servo-cont ro l

4-18

8/11/2019 884519


AMCP 706-123

MIL-L-10295A: LUBRICATING IL, INTERNAL OMBUSTION NGINE, SUB-ZERO

PROPERTIES VALUES

Color: Specific Gravity: Pour Point, °F (Max): S t a b l e Po u r Po in t , °F (Max ) : F l a s h Po in t , °F (Min ) : Vi s c o s i t y , c St : -40°F(Min)

-210°F (Max ) A d d i t i v e s :

E f f e c t o f A d d i t i v e s : I n c r e a s e in f o a m H o m o g e n e i t y Ran g e , °F

S t o r a g e S t a b i l i t y Ox id . C h a r a c t e r i s t i c s : ( f e r r o u s an d n o n f e r r o u s

e n g i n e p a r t s ) R i n g St ick : 120 h r E n g i n e Te s t

F o a m i n g : 75°F, a f t e r 5 . 0 m i n b l o w i n g , m l (Max ) 75°F, a f t e r 10.0 m i n s e t t l i n g , m l ( M a x )

200°F, a f t e r 5 . 0 m i n b l o w i n g , ml (Max )

200°F, a f t e r 10.0 m i n s e t t l i n g , ml (Max )

Rep ea t 7 5 ° F t e s t Co mp a tib i i i ty : Wa t e r Co n ten t , %

S u s p e n d e d Mat t e r, % S t o r a g e * a b i l i t y : NATO S y m b o l :

Recommended Ambient Temperature Range °F

NR NR Report

-65 -65 290

5.758,500 Allowed

None -65 to +250

No Separation

No C o r r o s i o n

N o n s t i c k , R e p o r t mm We a r

No l i m i t 300

No l i m i t

25 Sa m e as ini t . 7 5 ° F Te s t

Al l o i l s to Spe c . No n e No n e

NR No n e

-65 to 0

N o t e s : NR , no r e q u i r e m e n t s .

U s e : Lo w t e m p e r a t u r e lu b f or c r a n k c a s o f i n t e r n a l c o m b u s t i o n e n g i n e s . Ma y be s y n t h e t i c

4-19

8/11/2019 884519


AMCP 706-123

MIL-H-L3866B(MR) : H Y D R A U L I C FLUID, PETROLEUM BASE , ARTILLEHi RECOIL, SPECIAL

PROPERTIES VALUES

Co lo r : Green ( C l e a r )

S p e c i f i c G r a v i t y, 60/60, °F : 1 5 P o u r / C l o u d P o i n t s , ° F ( M a x ) : -5 0 / -4 0

F l a s h / F i r e P o i n t s , ° F (Min ) : 210/220

Vi s c o s i t y , cSt : -4 0 °F (Max ) - - -30°F (Ma x) 4 , 4 0 0

100°F (Mi n) 55 210°F (Min ) 1 5

A d d i t i v e s : x i d a t i o n I n h i b i t o r s , w t Approval Req_'d C o r r o s i o n I n h i b i t o r s , $ w t A p p r o v a l Req'd

Vi s c o s i t y I m p r o v e r s , $ w t < 17.5 O t h e r s None

Neutralization No . : g K O H / g (Ma x) 0 .3 0

P r e c i p i t a t i o n No. : (Ma x) 0.05

C o r r. a n d Ox id . S t a b i l i t y : t e e l -0 .20 168 h r at 212°F C o p p e r -0 .20

Max w t Ch g t Pi t t in g , E t c h o r C o r r. at 20 X N o n e

mg/cm 2 Viscosity Ch g at 100°F, $ -5 to + 20

Neutralization No . s 0 . 5 0 P r e c i p i t a t i o n No . g 0.05 I n s o l u b l e Mat'l o r G u m m i n g N o n e

Coppe r S t r i p C o r r. : h r at 212°F NR Lo w Te m p e r a t u r e S t a b i l i t y : 2 h r at -30°F No n g el , No . Sep.

R u b b e r Swel l : y p e L , 168 h r at 70°F, $ V o l Ch g a 25.0 D i e l e c t r i c St ren g th ; kv/imn (Min) 1 5 . 0 S h e a r S t a b . : P u m p ) ; 100°F, C y c l e s to r e d u c e Vi s e . 25 $ > Ref . F l u i d * Cor r. P r o t . ; ( b a r e s t e e l ) : 00 h r at 77°F, 100$ R . H . NR S a l t Water C o r r. ; ( b a r e s t e e l ) : 0 hr at 77 $ NR D i s t i l l a t i o n : 0$ E v a p o r a t i o n ; ° F (Min ) NR

5 0$ E v a p o r a t i o n ; ° F (Min ) NR

F o a m i n g : 75°F, a f t e r 5 . 0 min b l o w i n g ; m l (Max ) NR 75°F, a f t e r 10.0 min s e t t l i n g ; m l (Ma x) NR 200°F, a f t e r 5 . 0 min b l o w i n g , ml (Max ) H R 200°F, a f t e r 1 0 .0 min s e t t l i n g , ml (Max ) NR

R e c o m m e n d e d Te m p e r a t u r e Ran g e , ° F : — S e r v i c e P e r f . : Oi l Gear M3), Oil Te m p e r a t u r e ° F (Max ) NR Water C o n t e n t :


—, no i n f o r m a t i o n .

* . I .A . Re f . Oi l No . .

U s e : y d r o s p r i n g s an d b y d r o p n e u m a t i c a r t i l l e r y r e c o i l m e c b a n i m s

4-20

8/11/2019 884519


AMCP 706-123

MIL-H-13919B:HYDRAULICFLUID,PETROLEUM BASE, IRE-CONTROL

(NATO ymbol: None) a. eneral characteristics: This hydraulic fluid is a

rust inhibiting, petroleum base liquid, containing addi-

tives, or se t mbient emperatures bove °F. ASTM olor is Code N o. Max, bright n olor and free of haze.

b. sable emperatures: The perating emperature ange is ot pecified.

c. hemical composition: The base iquid s e- fined mineral oil, free of unrefined oils and other injurious ingredients which may affect the proper function of the iquid. The inished iquid ontains uitable ust- inhibiting and other approved additives.

d. ses:T his liquid is a medium grade rust-inhibiting, ambient temperature, ordnance hydraulic fluid for use n ire ontrol ystems, hydraulic variable peed

gears, nd n ther ydraulic echanisms here recommended.

e. imitations: This hydraulic fluid is no t suitable for xtreme emperature pplications, elow °F r above 200"F. It is not recommended or intended for use in ircraft.


MIL-L-17331F(SHIPS)Amendmen tl.L UBRICA TING OIL, TEAM TURBINE (NONCORROSIVE)

(NATO Symbol: 0-250; Military Symbol: 2190-TEP) a. eneral haracteristics: hi s iquid s e-

troleum base steam turbine lubricating oil which may

or may ot contain dditives. The liquid s noncorrosive and ha s work factor of 0.9 min. b. sable emperatures: The perating empera-

ture range is not specified, but general usage is between + 20°F nd 190°F with short duration elevated temperature use to 50°F.

c. hemical composition: This liquid is a homogeneous blend f virgin petroleum lubricating

oil lus equired dditives o meet equirements of the specification.

d. ses: This liquid is a steam turbine lubricating oil for main turbines and gears, auxiliary turbine instal- lations, certain hydraulic equipment, general mechani-

ca l ubrication, nd ir compressors. e. imitations: The iquid as imited se s y- draulic fluid and is no t for low temperatures (minimum recommended temperature is 20°F). It is compatible with eference oils urnished y he Government nd other oils o his specification.

f. ustodian: Navy-SH Project 150-N029Sh).

MIL-F-17111 ( NORD): FLUID, POWER TRANS- MISSION

(NATO Symbol: H-575) a. eneral haracteristics: his iquid s e-

troleum base, power transmission fluid suitable for use in aval ordnance ystems nvolving mechanical r fibrous type filters or centrifugal purification. t hall be noncorrosive to bearings and hydraulic systems, and shall not cause clogging of oil screens or valves. t has an ASTM olor of Code No. .

b. sable emperatures: The perating emperature ange is ot pecified. ' c. hemical composition: The inished iquid s

petroleum as e luid lus n ntiwear gent ricresyl phosphate, nd other pproved dditives hich m- prove the compounded fluid with respect to viscosity- temperature nd ubricating properties, esistance o

oxidation, nd corrosion protection. d. ses: This liquid is intended fo r use in connec-

tion with the hydraulic transmission of power, particularly n Naval ordnance hydraulic quipment.

e. imitations: Not for high temperature applications since the fluid s lammable.

f. ustodian: Air Force-11

MIL-L-17672B: LUBRICATING OIL, HYDRAULIC AND LIGHT TURBINE, NONCOR- ROSIVE

(NATO Symbol: H-573) a. eneral characteristics: This pecification ov - ers a multiclass mineral base hydraulic oil containing

anticorrosion nd ntioxidation additives: 1 . ilitary ymbol 07 5 T-H 2. ilitary ymbol 110 T-H 3. ilitary ymbol 135 T-H

b. sable emperatures: The perating emperature range is ot pecified.

c. hemical composition: This liquid is a blend of virgin petroleum ase ils nd dditives o meet e- quirements of this pecification; ncluding oxidation, corrosion, oa m and emulsion tests in addition o viscosity ange, lash, pour point, tc.

d. ses: This liquid is for steam turbines, hydraulic systems, water turbines, water-wheel ype generators, hydraulic-turbine overnors, nd ther pplications where a high grade lubricating oil having anticorrosion and antioxidation properties is equired.

e. imitations: There re o torage ife equirements, but he iquid as oo d torage properties f

4-21

8/11/2019 884519


AMCP 706-1 23

MIL-H-1391f-B: HYDRAULIC FL UID, PETROLEUM BASE, FIRE CONTROL

PROPERTIES VA L U E S

Col or : No . 5 (ASTM) S p e c i f i c G r a v i t y, 60/60, °F : H R P o u r / C l o u d P o i n t s , ° F (Ma x) : -5 0 /NR F l a s h / F i r e P o i n t s , ° F (Min ) : 225/NRVi s c o s i t y , cSt: -4 0 °F (Max ) 7 , 5 0 0

-30°F (Max ) NR 1 0 0 °F (Mi n) 38 210°F (Mi n) 1 0

A d d i t i v e s : O x i d a t i o n I n h i b i t o r s , % wt Approval R e q ' d C o r r o s i o n I n h i b i t o r s , % wt A p p r o v a l R e q ' d Vi s c o s i t y I m p r o v e r s , % w t Approval R e q ' d O t h e r s N o n e

Neutralization No . : g K O H / g (Max ) NR P r e c i p i t a t i o n No , : Max) 0.05 C o r r. a n d Oxid. S t a b i l i t y : t e e l -0 .20

168 h r at 2 1 2 °F Co p p er -0.20 Max w t Ch g , P i t t in g , tch o r Corr. at 20X S l i g h t E t c h

m g / c m2 Viscosity Ch g at 100°F, % -5 to + 20 Neutralization N o. + 0 . 5 0 P r e c i p i t a t i o n N o. £ 0.05 I n s o l u b l e Mat'l or Gumming N o n e

C o p p e r S t r i p C o r r. : h r at 212°F No E t c h or Pi t Lo w Te m p e r a t u r e S t a b i l i t y : 2 h r at - 3 0 ° F N o n g e l , No Sep. R u b b e r Swel l : y p e L , 168 hr at 70°F, % V o l Ch g S 2 5 . 0

D i e l e c t r i c S t r e n g t h : V/mm (Min) NR S h e a r S t a b . : ( P u m p ) ; 100°F, C y c l e s to reduce Vise. 25 > Re f . F l u i d * C o r r. P r o t . ; ( b a r e s t e e l ) : 00 hr at 7 7 ° F, 100 R.H. S l i g h t Tr a c e S a l t Water C o r r. ; ( b a r e s t e e l ) ; 20 h r at 7 7 S l i g h t T r a c e D i s t i l l a t i o n : 10 $ E v a p o r a t i o n ; ° F (Min ) 49 0

5 0$ E v a p o r a t i o n ; ° F ( M i n ) 575 F o a m i n g : 75°F, a f t e r 5 . 0 min b l o w i n g ; ml (Ma x) No l i m i t

75°F, a f t e r 1 0 .0 min se t t l i ng ; ml (Max)

£ 100 200°F, a f t e r 5 . 0 min blowing ml (Max) No l i m i t 200°F, a f t e r 1 0 .0 min s e t t l i n g , ml ( M a x ) 25

Recommended Te m p e r a t u r e Range , ° F: A m b i e n t > 0 S e r v i c e P e r f . : ( O i l Gear M3), Oil Temperature °F (Max) ä 20 5 Water C o n t e n t : N o n e

N o t e s : R, n o r e q u i r e m e n t s . * . I .A . Re f . Oi l No . 1 . U s e : i r e - c o n t r o l h y d r a u l i c v a r i a b l e speed gears and other mec a n i s m s . u s t i n h i b i t i n g .

No t f o r a i r c r a f t .

4-22

8/11/2019 884519


AMCP 706-123

MIL-F-17111 (NORD): FLUID, POWER RAIISMISSION

PROPERTIES VALUES

Color: No. 2 (ASTM) Specific Gravity: NR Pour oint, F, (Max): -40 Flash/Fire oints, °F Min): 220/235 Viscosity, cSt: -25°F Max) 600

0°F Max) 215 100°F Min) 27 210°F Min) 10

Additives: Antiwear; $ t Approval eq'd Oxidation nhibitor, % t Approval eq'd Corrosion nhibitor, % t A.pproval eq'd Viscosity mprover, % t Approval eq'd Tricresyl hosphate, ^ t 1.0 ± .1

Neutralization No.: mg OH/g Max) 0.3

Precipitation o.: 0.05 Water ontent: $ Max) None L ow emperature tability: 72 r t -35°F No olids, nongel Rust revention: (bare steel), 24 r t 40°F No Visual vidence Corr. and xid. Stability: copper t oss; g/cm s .20

336 r t 20°F $ ise hg; 210°F 0 o +25 Fluid nd water > ise hg; 0°F 0 o +25

Neutralization o. (Max) 0.50 Oil-Insoluble esidue; $ t

(Max) 0.50 Color; (ASTM) (Max) No. 5

Copper Wire xid. : jo ise hg; 210°F 0 o +15 72 r t 00°F % ise hg; 0°F 0 o +15

Fluid nd Water Neutralization o. (Max) ä 0.50 Shear tability: > ise hg t 10°F Max) -25

5,000 ycle ump Fluid Condition No eparation r ludge

100°F nd ,000 si Neutralization o. (Max) 0.50 Wear-Gear ump: Wt oss/Pump ear, g 0.20 Max) (100 r, 100°F, 1,000 psi) Wt Loss/Bronze Bushing, g 0.04 Max)

Wt oss/4 ronze ushings, g 0.08 (Max) Evaporation: 72 r t 90°F; Vise; 210°F, cSt 3,000 Max) Water ludging: 24 r t 00°F; f ise Chg t 00°F -2 to +10 NATO ymbol: H-575 Recommended emperature ange F: NR Foaming: NR Storage tability: NR

Notes: NR, no requirements. Use: Fluid or ydraulic transmission f ower, particularly in Naval rd. Hyd. equipment.

4-23

8/11/2019 884519


8/11/2019 884519


A MC P 706-123

MIL-L-17672B: LUBRICATING IL, HYDRAULIC ND IGHT URBINE, NONCORROSIVE

PROPERTIES VALUES

Color: NE Specific Gravity: NR eport

Pour oint, °F Max): IL-Symbol 075 -H -20 MIL-Symbol 110 -H -10 MIL-Symbol 135 -H 0

Flash oint, °F Min): MIL-Symbol 075 -H 315 MIL-Symbol 110 -H 325 MIL-Symbol 135 -H 340

Viscosity, cSt: 0°F, IL-Symbol 075 -H 1,200 Max) 0°F, IL-Symbol 110 -H 2400 Max) 10°F, MIL-Symbol 135 -H 2800 Max) 210°F, MIL-Symbol 075 -H 4.3-5.3210°F, MIL-Symbol 110 -H 5.3-6.7 210°E MIL-Symbol 135 -H 6.7-7.7

Neutralization No.: mg 0H/g Max) 0.20 Neutrality, Qualitative:• Neutral Copper trip: 3 r t 12°F Max) No. 1 ASTM) Rust reventative: 24 r t 40°F N o Corrosion Water ontent: $ Max) None Ash, Sulfated Residue < f> Max) NR ReportAdditives: Allowed Homogeneity emperature ange, °F: MIL-Symbol 075 -H -20 o 50

MIL-Symbol 110 -H -10 o 50 MIL-Symbol 135 -H 0 o 50

Emulsion: 130°F, 0 in ettling, ax Cuff, ml 3.00 Foaming: 75°F, after .0 min lowing, l Max) No limit

75°F, after 0.0 in ettling, ml Max) 300 200°F, after .0 min lowing, ml Max) No limit 200 F, after 0.0 in ettling, l Max) 25 Repeat 5°F est Same s init . 75°F est

Oxid. Test: Time o each Neut. No. 2.0 m g DH; hr Max) 1,000 Contamination: (325 Mesh); mg/gal Max) 10.0

6.0 ml ibers/gal Max) 1.0 NATO ymbol: H-573 Storage tability: — Recommended Temperature ange, °F: — Compatibility: Ref. and pec, oils

Notes: NR, no requirements. —, no information.

Use: Mineral oil nd dditives for team urbines, hyd. systems, water urbines and other systems, anticorrosion nd ntioxidant additives are requ ired.

4-25

8/11/2019 884519


8/11/2019 884519


AMCP 706-123

MIL-L-21260A: LUBRICATING IL, INTERNAL OMBUSTION ENGINE, PRESERVATIVE

PROPERTIES VALUES

Color: NR Specific Gravity: NR Pour Point, °F Max): Grade 1 -20

Grade 2 0 Grade 3 +15

Stable Pour oint, °F Max): Grade 1 nly -20 Flash oint, °F Min): Grade 1 360

Grade 390 Grade 3 400

Viscosity, cSl: Grade 2,614/5.44-7.29 (Vise, 0°F Max)/ Grade 2 43,570/9.65-12.98

Vise, 210°F) Grade 3 NR/16.83-22.75 Viscosity ndex: Grade 3 nly 75 Volatile Matter: (4 r team bath); % wt 2.0

Additives: Allowed Corr. Prot.: 200 r, high-humidity; % orr. Trace Only (Bare Steel, 77°F) salt water ip, 20 r ry; % orr. Trace Only Acid leut.: 77 F, acid ol. dip, 4 r in oil; $ orr. No Corrosion Oxid. Characteristics: (ferrous and onferrous engine

parts) Noncorrosive Compatibility: MIL- L- 2104 Foaming: 75°F, after .0 in lowing, ml (Max) No imit

75 °F, after 0.0 in ettling, ml Max) 300 200°F, after .0 in lowing, ml (Max) No limit 200°F, after 0.0 in ettling, ml Max) 25 75°F, Repeat 5°F Test Same as init . 75° Test

Water Content: $ _„

NATO Symbol: None Storage Stability: -- Recommended emperature ange, °F --

Notes: N R, no equirements. --, no information.

Use: Light, medium, and eavy reservative lub and reservative oil or eciprocating internal ombustion ngines.

4-27

8/11/2019 884519


AMCP 706-123

,MIL-F-25598(USAF): OIL, HYDRAULIC, MISSILE, PETROLEUM BASE

PROPERTIES VALUES

Color: Purple (Clear and ransparent) Specific Gravity: NR

Pour oint, °F Max): -90

Flash oint, °F Min): 200

Viscosity, cSt: -65°F Max) 600 -50°F Max) 240

-40°F Max) 140 0°F Max) 28

130 °F Min) 2.6

160°F Min) 2.0

210 °F Min) 1.25

Neutralization o.: mg OH/g Max) 0.20

Precipitation o. 0 Additives; $ wt: Antiwear (tricresyl hosphate) Max) 0.05 .1

Oxidation nhibitor Max) < .0

Corrosion nhibitor (Max) As Req'd Viscosity mprovers (Max) None Others No Four oint ep.

Corr. and xid. Stability: Steel + .20 168 r t 50°F Aluminum Lloy ± .20 M ax t hg, mg/cm2 Magnesium Alloy + .20

Cad.-Plate + .20 Copper + .60 Pitting, Etch nd Corr. at 0X None (slight tain) $ Vise Chg t 30°F -5 o 20 Neutral. No. Increase (Max) 0.20 Insoluble Mat l r umming None

Lo w Temperature Stability: 72 r at 65°F No solids, nongel Rubber well: Type "L", Vol, < f, 1 9 - 26.5 Evaporation: 4 r at 50°F Oily, nontacky Copper Strip. Corr.: 72 r t 12°F No Corrosion slight tain)

Corr. Prot.: Steel, 100 r, 120°F, 100$ R.H. Trace f orrosion Solids: 250 c, 0.047 m ilter; M ax art ize 30 icron Water ontent: $ 0.005Storage Stability: NR Recommended emperature ange, °F -- NATO ymbol: None Compatibility: Not nterchangeable

Notes: N R, no equirements. --, o nformation.

Use: Missile yd. ystems sing ynthetic material.

4-28

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AMCP 706-123

MIL-H-27601A(USAF) : HYDRAULIC FLUID, PETROLEUM BASE , HIGH TKMPERATURE, F L I G H T VEHICLE

PROPERTIES VALUES

Co lo r : NR S p e c i f i c G r a v i t y : NR - R e p o r t Po u r Po in t , ° F (Max ) - 6 5 F l a s h Po in t , ° F (Min ) : 360 Vi s c o s i t y , c St : 6 5 ° F R e p o r t

- 4 0 ° F (Max) 4 , 0 0 0

0° F (Max) 38 5 210°F (Min) 3. 2 5 5 0 ° F (Min) R e p o r t

Vi s c o s i t y In d ex : M i n ) 8 9 Neutralization N o . : g KOH/g (Max ) 0 .2 0 A d d i t i v e s , $ w t: ntiwear ( t r i c r e s y l p h o s p h a t e ) ( J f e x ) 1. 0

Oxidation I n h i b i t o r s ( b i s - p h e n o l ) 0 .4 5 - 1. 0 O t h e r s Approval Reqjd

C o r r. a n d Ox id . S t a b i l i t y : o p p e r 0 .6 0 48 h r at 347°F Ty p e 35 0 St . S t e e l 0 .2 0

Max vt Ch g , Ty p e 35 5 St . S t e e l 0 .2 0 mg/cm 2 Ty p e 4 4 0 St . S t e e l 0 .2 0

S i l v e r 0 .2 0

% Vi s e . Chg. at 100°F -5 to + 20

Neutralization N o. ( M a x ) 2. 0 I n s o l u b l e Mat'l < f> vt (Ma x) 0. 1

T h e r m a l S t a b i l i t y : -10 To o l S t e e l 0 .1 0 6 hr at 700°F, 52100 S t e e l 0 .1 0 20 psig N i t r o g e n aval B r o n z e 0 .1 0 a t m o s p h e r e , f> Vi s e Ch g at 100°F (Ma x) 25

N e u t r a l . No . (Max ) 0 . 4 0 R u b b e r S w e l l ( S y n ) : i t o n A o r B ; 72 hr at 400°F, f, Vo l . + 1 0 . 0 (Max ) L u b r i c i t y ; ( S h e l l 4 - B a l l Te s t e r ) : kg l o a d 0 .2 1

1. 0 h r at 60 0 r p m , 167°F, 10 kg l o a d 0.30

52100 S t e e l Max S c a r D i a mm 4 0 kg l o a d 0.65 Solid P a r t i c l e s : i m e to f i l t e r 10 0 m l , min (Ma x) 1 0 .0 ( 0 . 4 5 Micron f i l t e r ) Max P a r t i c l e o n f i l t e r ( M i c r o n ) 1 0 0 .0 C o m p a t i b i l i t y : All f l u i d s to t h i s S p e c . F o a m i n g : 75°F, a f t e r 5 . 0 min b l o w i n g , ml ( M a x ) 75

75°F, a f t e r 3. 0 min s e t t l i n g , ml ( M a x ) None200°F a f t e r 5 . 0 min b l o w i n g , ml (Max ) 75 200°F a f t e r 3. 0 min s e t t l i n g , ml (Ma x) N o n e

R e p e a t 7 5 ° F Te s t S a m e as i n i t . 75 ° Te s t Water C o n t e n t : f> (Max ) 0 .1 0 T r a c e S e d i m e n t : f> V o l (Max ) 0.025 D i e l e c t r i c S t r e n g t h : ( v o l t / m i l ) , 6 8 °F ; ( M i n ) 300 S p e c i f i c H e a t : ( B t u / l b ° F) at 200°F (Min ) 0 . 4 8 4 T h e r m a l Cond.: ( B t u / ( f t 2 ) ( h r ) ( ° F ) / f t t 4 0 0 ° F (Min ) 0.063 T h e r m a l E x p a n s i o n / ° F : at 4 0 0 ° F (Max ) 0 .0 0 0 6 0 B u l k M o d . : ( i s o t h e r m a l s e c a n t , 0-10 4 p s i , 100°F), ps i > 200,000

Recommended Te m p e r a t u r e Ran g e ,

F : -4 0 to + 5 5 0 S t o r a g e S t a b i l i t y : NR

N o t e s : R, no r e q u i r e m e n t s . U s e : y d. S y s t e m s of f l i g h t v e h i c l e s .

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AMCP 706-123

MIL-L-45199A: LUBRICATING OIL, INTERNAL COMBUSTION ENGINE, HIGH OUTPUT DIESEL

PROPERTIES VALUES

Color: Specific Gravity: Pour Point, °F (Max): rade 1 0

Grade 30 Grade 5 0

Stable Pour Point, °F (Max): Grade 1 0 (only) Fl a sh Point, °F (Min): rade 1 0

Grade 30

Viscosi ty, cSt: 0°F; O°F;

O°F;

210°F;

210°F; 210°F;

Additives: Oxid. Charac ter is t ics

Grade 50 Grade 10 ( M a x ) Grade 30 (Max) Grade 50 ( M a x ) Grade 10 Grade 30 Grade 50

( fe r rous an d nonfer rous engine part s )

Lo w Tempera tu re Deposit: 18 0 h r lo w temp c y c l e Ring Stick: 20 hr engine tes t Light-load eposit ccumulation: 120 r ngine est Foaming: 75°F, after .0 in blowing, ml Max)

75°F, af te r 10.0 m in sett l ing, m l ( M a x ) 200°F after 5. 0 min b lowing , m l (Max) 200°F after 10.0 m in sett l ing, m l (Max) Repeat 75°F Tes t

Oi l Additive Stabil i ty: Storage Stability: Compatibility: Recommended Tempera tu re Range, °F : N A T O ymbol:

N R N R eport

-20 0

NP -20 360 390 NP

2,614 43,570

NP 5.44-7.29 9.65-12.98

NP Allowed (N o erefined)

No orrosion N R

No tick, in. ea r NR

No Limit 300

No Limit 2 5

Same s init. 75°F est No dditive nstability

Al l Oils t o Spec. Above -20

None

Notes: R, no requ irements . —, no information. NP, no product .

Use: r a n k c a se lu b of h igh output d iese ls w her e tempera tu re i s above -20°F. syn the t ic base .

Ma y be

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AMCP 706-123

combination hereof, ith dditive aterials detergents, dispersants, oxidation inhibitors, etc.) necessary to meet the equirements of this specification. No re - refined components are allowed.

d. ses: This liquid is for crankcase lubrication of high output upercharged nd unsupercharged iesel engines under all conditions of service at ambient tem-

peratures above-20°F. e. imitations: This iquid s not or se t ow temperature onditions. t s ompatible with ll ils qualified o this specification.

f. ustodians: Army-MR Navy-SH Air Force-67

MIL-H-46001A.HYDRA ULIC FL UID, PETR OLEUM BASE, OR

ACHINE OOLS, TYPES , I, II, AND IV

(NATO Symbol: None) a. eneral characteristics: This iquid s multi-

grade efined petroleum hydrocarbon hydraulic luid containing additives. t has a viscosity ange of 30 to 12 1 cS t at 100°F, and a minimum viscosity index of 80 .

b. sable emperatures: The operating emperature ange s not pecified, but mbient emperatures should be above 20°F.

c. hemical composition:The finished liquid shall be petroleum ase fluid ontaining additives ecessary to meet the requirements of this specification-i.e., oxidation, orrosion, oam, lash, tc.

d. ses: This liquid is primarily for use in hydraulic systems of metalworking machine tools. The selection of the particular yp e of liquid s based n luid

viscosity ecommendations of machine ool manufacturers. he inished iquid hall e ompatible with other liquids meeting this specification.

e. imitations: This liquid is not suitable for low temperatures, nd mbient emperatures hould e above + 20°F.

f. ustodians: Army-MR Navy-SA Air Force-11

MIL-L-46002(ORD): LUBRICATING IL, CON- TACT AND VOLA TILE, COR -

ROSION INHIBITED

(NATO Symbol: None) a. eneral characteristics: This oil is a dual grade

volatile corrosion inhibited lubricating oil for preserva- tion ofmaterial in enclosed systems. Light and medium viscosity ils re vailable with pour points of-50°F and -10°F.

b. sable emperatures: The perating emperature range is not specified, but the oil or oil-water vapors shall be capable of protecting parts from corrosion throughout a temperature range of +40° to 130T.

c. hemical composition: This oil is a volatile corrosion nhibited, petroleum ase il ontaining dditives necessary to meet specification requirements. The

oil shall contain no ingredients injurious to personnel using easonable afety precautions nd must e re e from disagreeable or offensive odors.

d. ses: This oil is intended fo r use in the preserva- tion of enclosed systems where the volatile components will provide protection bove he il evel. t s lso effective as a contact reservative.

e. imitations: The oil is not intended for use as an operational preservative oil and should not be used in applications here agnesium, admium-plated r rubber omponents re present. Generally, t hould not be mixed with other oils to same specification due to wide product olerances.

f.

ustodian: Army-MR

MIL-H-46004(ORD):HYDRAULIC FLUID, PETRO- LEUM BASE, MISSILE

(NATO Symbol: None) a. eneral characteristics: This pecification ov -

ers a low viscosity liquid containing approved additives for low temperature missile applications. t has a viscosity of 300cS t at-65°F and a pour point of-75°F. The liquid s dyed ellow for identification urposes.

b. sable emperatures: The perating emperature range is not pecified.

c. hemical composition: This iquid s efinedpetroleum base liquid with additives to improve oxidation resistance and wear (tricresyl phosphate, 0.5 - + 0.1 percent by weight as the antiwear agent). The finished product hall ontain o pour point depressants, iscosity ndex mprovers, dmixtures of resins, ubber, soaps, ums, atty ils, xidized ydrocarbons, or other additives not pecifically approved.

d. ses: This iquid s esigned or use in missile hydraulic ystems pplications t mbient emperatures below 0°F.

e. imitations:Th\s liquid is not for high temperature or

high load applications. It is not interchangeable

with Hydraulic luid, astor Oil Base blue olor), Specification IL-H-7844. his iquid hall ot e mixed ith, ut ay e ubstituted or , ydraulic Fluid, etroleum ase, pecification IL-H-5606B, for low emperature operation.


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AMCP 706-123

MIL-H-4S001A: H Y D R A U L I C FLUID, P E T R O L E U M BASE , FOR MACHINE TOOLS, TYPES I, II , III , AND IV

PROPERTIES VALUES

C o l o r : NR S p e c i f i c G r a v i t y : NR Pour P o i n t , C

F (Max ) : Ty p e I +1 0 Ty p e II +1 0 Ty p e II I +10 Ty p e IV +20

F l a s h Poin t , ° F ( M i n ) : Ty p e I • 325 Ty p e II 325 Type II I 35 0 Ty p e IV 375

Vi s c o s i t y, c St : 100°F Ty p e I 30-37 Ty p e II 4 2 -5 2 Ty p e II I 62-70 Ty p e IV 106-121

Vi s c o s i t y In d ex : (Min ) 80 Neutralization No . : g K O H / g (Max ) 0.20 A d d i t i v e s : Approval R e q ' d Oxidation S t a b i l i t y : B a r e S t e e l S t r i p 0 .2 0

168 h r at 212°F Coppe r S t r i p 0 .2 0 Max w t Chg, P i t t in g , E t c h a n d Co rr. at 20 X None

mg/cm 2 $ Vi s e . Ch g at 100°F (Max ) 2 5 . 0 N e u t r a l . No . Ch g ( M a x ) + 0 . 1 5 P r e c i p i t a t i o n No . (Max ) 0.05 I n s o l u b l e Mat'l o r Gumming None

C o m p a t i b i l i t y : All F l u i d s to T h i s Sp ec . Water Conten t : N o n e F o a m i n g : 5 °F, a f t e r 5 . 0 min b l o w i n g , ml (Max ) No l i m i t

7 5 °F, a f t e r 1 0 .0 min s e t t l i n g , ml ( M a x ) 100 200°F, a f t e r 5 . 0 min b l o w i n g , ml (Max ) No l i m i t 20 0 ° F, a f t e r 1 0 .0 min s e t t l i n g , ml (Max ) 25 R e p e a t 7 5 ° F t e s t S a m e as i n i t . 7 5 ° F 1 es t

E m u l s i o n : f t e r 30 min s e t t l i n g ; f o a m o r c u f f (Max ) 3. 0 ml ( O i l an d Wa t e r , 130°F, 5 . 0 min s t i r , 30 min s e t t l i n g ) Tr a c e C o p p e r C o r r. : 168 h r at 212°F No Pi t o r EtchR u s t P r e v e n t i o n : b a r e s t e e l ) , 24 h r at 130°F N o n e Recommended Te m p e r a t u r e R a n g e , c F ; NR NATO S y m b o l : N o n e S t o r a g e S t a b i l i t y : NR


U s e : y d r a u l i c s y s t e m s of metal w o r k i n g machine t o o l s .

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AMCP 706-123

MIL-L-46002(ORD) : L U B R I C AT I N G OIL, CONTACT AN D VOLATILE, CORROSION I N H I B I T E D

PROPERTIES VALUES

Col or : NR S p e c i f i c G r a v i t y : NR P o u r Poi n t , ° F (Ma x) : G r a d e 1 -50

G r a d e 2 -10 F l a s h Poi n t , ° F (Min): G r a d e 1 24 0

G r a d e 2 25 0 Vi s c o s i t y , cS t : -4 0 °F (Ma x) G r a d e 1 10,000

-4 0 °F (Ma x) G r a d e 2 NR 1 0 0 °F (Mi n) G r a d e 1 1 2 100°F (Mi n) G r a d e 2 95 to 125 210°F G r a d e NR 210°F G r a d e 2 9 . 6 5 to 1 2 .9 8

P r e c i p i t a t i o n N o . : l/10 ml (Max ) 0.05 Hydrocarbon S o l u b i l i t y : 4 h r at 7 7 °F No S e p a r a t i o n C o r r o s i v e P r o t e c t i o n : umidity Cab in e t , 30 0 h r at 1 2 C°F No Corrosion

Va p o r P h a s e ; 6 h r at 4 0 ° F a n d 18 h r at 130°F No C o r r o s i o n

Va p o r P h a s e P ro t . a f t e r e x h a u s t i o n ; 6 h r at 210°F No C o r r o s i o n

Acid N e u t . : 77°Fj acid s o l . dip, 4 hr i n o i l ; $ Cor r. No C o r r o s i o n Water D i s p l a c e m e n t / S t a b i l i t y : . 0 hr at 77°F No C o r r o s i o n C o r r o s i o n I m m e r s i o n : luminum 0 .2 0

7 d a y s at 130°F S t e e l 0 . 5 0 Max w t Chg; mg/cm C o p p e r 1 . 5 0

E v a p o r a t i o n : w t Vo l a t i l e matter ( M a x ) , G r a d e 1 1 5 . 0 (2 1 0 °F) $ w t Vo l a t i l e matter ( M a x ) , G r a d e 2 5. 0

i Vi s e , Ch g at 100°F, G r a d e 1 -5 to + 20 # Vi s e , Ch g at 100°F, G r a d e 2 -5 to + 20

NATO S y m b o l : N o n e S t o r a g e S t a b i l i t y : — Recommended Te m p e r a t u r e R a n g e , ° F : Up to 13 0

C o m p a t i b i l i t y : No t I n t e r c h a n g e a b l e


—, no i n f o r m a t i o n .

U s e : r e s e r v a t i v e o i l f o r c l o s e d s ys t e r. s , both as v a p o r a n d c o n t a c t lub. o t recommended as an o p e r a t i o n a l o i l .

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AMCP 706-123

MIL-H-4 6 0 0 4 (0 RD): H Y D R A U L I C FL UID, PETROLEUM B A S E , MISSILE

PROPERTIES VALUES

Col or : Yellow ( C l e a r an d Tr a n s p a r e n t ) S p e c i f i c G r a v i t y : R e p o r t Po u r Po in t , ° F Max): -75 Flash Poi n t , ° F M in) : 200 Vi s c o s i t y , cSt: -6 5 °F ( Max ) 300

-4 0 °F (Max) 7 5 100°F (Mi n) 2. 8

Neutralization H o . : g KOH/g Max) 0.20 A d d i t i v e s : ntiwear ( t r i c r e s y l p h o s p h a t e ) , $ wt 0.5 io . i

Oxid I n h i b i t o r s , jo wt s 2. 0 Po u r P o i n t D e p r e s s a n t , % wt None Viscosity I m p r o v e r s , $ wt Hone O t h e r s Approval Req'd

Precipitation Wo . : 0

Water Con t e n t , $ (Max) : 0.015 Corr. and Oxid . S t a b i l i t y : S t e e l ± 0 . 2 0

168 h r at 2 5 0 ° F Aluminum Alloy ± 0 . 2 0 Max wt Chg, m g / c m Magnesium Alloy ±0.20

C a d . - P l a t e ± 0 . 2 0 Copper ± 0 . 6 0 Pi t t i ng , E t c h a nd C o r r at 20 X None •f , Vi s e Ch g at 100° F -5 t o + 20 N e u t r a l . No . I n c r e a s e (Max) 0.20 I n s o l u b l e Mat'l or G u m m i n g ;

% w t NoneCo p p er C o r r : 72 h r at 2 1 2 °F S l i g h t St a i n ; no Pi t s Low Te m p e r a t u r e S t a b i l i t y : 72 h r a t -65°F No Sol i ds , n o n g e l Rubber S w el l : Ty p e L, Vol Chg; jo 1 9 -2 6 .5 S o l i d Pa r t i c l e Cont e n t : -1 5 M i c r o n s 2 , 5 0 0

(Ma x P a r t s / 1 0 0 m l) 16-25 M i c r o n s 1 ,000 26-50 M i c r o n s 25 0

5 1 -1 0 0 M i c r o n s 25 Ov er 10 0 M i c r o n s 2

E v a p o r a t i o n : 4 h r a t 150°F O i l y, ontackyC o r r o s i v i t y : r a s s - s t e e l , 10 d a y s , 7 5 °F, 5 0$ R . H . No C o r r o s i o n Recommended Temperature Ran g e , °F: < 20 NATO Sym bol : NoneS t o r a g e S t a b i l i t y : — C o m p a t i b i l i t y : No t I n t e r c h a n g e a b l e Water S t a b i l i t y : 1 h r at 77°F, 5 0$ R . H . — Humidity Ca bi ne t : 8 d a y s , 5 0$ R . H . — Machine Gun Te s t : -75°F, 25 R o u n d s —

N o t e s : ~ —, no i n f o r m a t i o n .

U s e : Guided m i s s i l e h y d . s y s t e m s at l o w t e m p e r a t u r e . S u l s t i t u t e f o r MIL-H-5 6 0 6 B.

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AMCP 706-123

MIL-H-19457B(SHIPS): HYDRAULIC FLUID, FIRE ESISTANT

Type I Type IIPROPERTIES Lo w Viscosity High Viscosity

Color: Green Green Pour oint, °F Max) 0 25 Viscosity, cSt: 100°F 43-50 125-135

210° F Min) 4.8 6.3Neutrality (Qualitative): Methyl range Neutral Yellow) Neutral Yellow) Neutralization o. (Acid): mg KOH/g Max) 0.10 0.10 Evaporation: 22 r t 10°F, $ wt Loss (Max) 0.30 0.30 Foaming endency: at 5°F No imit No imitFoam tability: 10 min fter ollapse, l oam Max) 300 300 Emulsion est: 130°F, Settling ime, in Max) 30 30 Precipitation o.: (90-95°F), l (Max) 0.01 0.01Specific Gravity: No imit (Record] No imit (Record) Refractive ndex, % a t 0°C do imit (Record] No imit (Record) Corrosion: Brass ±0.2 +0.2

7 days at 130°F Zinc ±0.2 +0.2 Max t chg, Steel +0.2 +0.2 mg/cm Aluminum ±0.2 +0.2

Visual Pitting r tch. None None Compatibility with ackings: tny uitable Any uitable

for CP for CP Butyl ubber well: % ol hg ±5.0 f C P +5.0 f C P Fire Resistance: CFR ompression Ratio (Min) 42:1 42;1Viscosity hear tability: Vise chg t 00°F Max) -10 -10

5,000 ycles, 1,000 si Visual eparation None None at 00°F Visual ecomposition None None

Sludging None None Neutralization Acid) No.:

mg DH/g (Max) 0.5 0.5Bearing ub., 208 Ball Bearing: 4,600 b ,750 pm li fe) £50$ Symbol

2110H £50$ ymbol 110H

Hydrolytic tability: Copper; t oss; g/cm2

Max) 0.3 0.348 r t 00°F Copper, Visual Corr None None

and pm Water ayer cidity: mg/K0H Max) 5.0 5.0 Acid No. Chg of Fluid; g DH/g

fluid to.2 Max ±0.2 Ma: Insolubles, $ (Max) 0.5 0.5

Handling roperties: Toxic * Toxic * NATO ymbol: H-580 None Recommended Operating emp Range, °F Low- >25 > 40

High 160-210 160-210 Storage tability: -- — Compatibility: Other luids -- -- ßase luid: Phosphorus ster Phosphorus ster

Notes: — no information. »Material ualified nder IL-H-19457B(SHIPS) has low rtho somer content n rder

to ass the specification toxicity equirement. T le Bureau f edi cine nd urgery

has approved the hipboard se f hese ualified Products as a es ult of areful consideration y ommittee f ompetent toxlcolo ?ists. Container 3 ust e roperly marked with warning abels as required y the pec .fication.

Use: Hydraulic ystems nd ir ompressors here ire es sistant fluid s leeded.

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A MC P 706-123

MIL-H-8446B: HYDRAULIC FLUID, NONPETROLEUM BASE, AIRCRAFT

PROPERTIES VALUES

Color: NR Pour Point, °F (Max): -75 Flash Point, ° F (Min): 395 Autogenous Igni t ion Temp, ° F (Min): 700 Viscos i ty, c S t : -65°F (Max) 2,500

100°F Report 210° F Report 400°F (Min) 2. 5

Vapor P res s u re at 400°F; m m of H g (Max) 5 .0 Wa t e r Content, $ w t (Max): 0.010 Densi ty, at 60°F, (g / cc) Report Specific Heat (Btu / lb ° F ) : 100°F Report

200° F Report 300°F Report

400°F T h erm a l Conduct iv i ty, B t u / (h r ) ( f t 2 ) ( f t / °F ) : 00°F

Report Report

200°F Report 300°F Report 400° F Report

Lo w Temp Stabil i ty: 7 2 hr at -65°F Nongel, No Solids Corr nd Oxid Stabil i ty: Steel ±0.2

72 hr at 400°F Aluminum ±0.2 Ma x w t chg, Copper mg /cm Silver

±0 .4 ±0 .2

Pitt ing, E tch or Corr at 20X None •j o Vise Ch g at 210°F (Max) ±35.0 Acid W o. m g K0H/g Max) 1.0 Insoluble Mat ' l or gumming None

Hydro ly t ic Stabil i ty: opper wt c h g : g / c m Max) +0.50 48 hr at 200°F Copper Pit or Etch None an d 5 r pm Copper Corrosion (Max) No . 1 (ASTM)

Acid No . Wat e r ; m g K0H/g (Max) 0.50 Acid No . Oil; m g K 0H /g (Max) 0.50 Vi s e Ch g of Oi l at 210°F, # (Max) ± 2 0 . 0 : Inso lub le mat ' l ; % w t (Max) 0.50

Rubber Swell: 7 0 hr at 250°F; Type S, $ Vo l Ch g +1 5 to +2 5 Foaming: il a n d foam af t er 5. 0 m in b lowing , m l (Max) 60.0

(200 m l sample) oa m Col lapse Time, Mi n (Max) 10.0 Shear Stabil i ty: is e Decrease at 210°F £ MIL-F-5602

(5 ,000 cycles , 2 ,500 psi , 275°F) Acid No. Increase (Max) 0.50 We a r Tes t (200 hr , 275°F, 3,000 ps i an d 3,600 rpm): s MIL-H-5606B Compat ib i l i ty : Al l Fluid to Spec. Storage Stabil i ty: 2 months , dark s torage No Sludge or Separat ion Re c o m m e n d e d Opera t ing Temp Range, ° F : -65 to 4 00 NATO Symbol: None Notes: R, no requi rements .

Report , no l imit , r ep o r t data.

Use: H i g h tempera tu re a i r c r a f t h y d rau l i c s y s t em s an d o t h e : sys tems requ ir ing wide tempera- t u re , stable h y d rau l i c f luid.

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AMCP 706-123

MIL-L-6085A: UBRICATING OIL, INSTRUMENT, AIRCRAFT, LOW VOLATILITY

PROPERTIES VALUES

Color: Clear: N o . 5 (ASTM) Pour Point, ° F (Max): -70 Flash Point, ° F (Min): 365 Vi s co s i t y, cSt: -65°F (Max) 12,000

130°F (Min) 8. 0 Addi t ives : xidation Inhib i tors , % w t Allowed

Corrosion Inhib i tors , $ v r t Allowed Viscosi ty Improvers , $ w t None Pour Point Depressant , $ wt None

Acid or Neu tra l iza t ion Ho.: g KOH/g Max) Report Prec ip i ta t ion No.: (Min) 0 Evaporat ion: 2 hr a t 210°F, f> r t Loss (Max) 1. 0 Corr. a n d Oxid. Stabil i ty: t eel ±0.2

168 hr at 250°F Aluminum +0.2

Ma x w t chg, Magnesium ±0.2

mg/cm^ Cad.-Plate ±0.2 Copper ±0.2 Pitting, Etch, or Corr. at 20X None Vi sc o s i t y Ch g at 130°F, # (Max) ± 5 . 0 Neutra l iza t ion N o . Increase 0.50

Lo w Temp t ab i l i ty : 72 hr at -65°F Nongel, No Separa t ion Protection: B are s teel panels ; 100 h r at 77°F an d 100$ Corr. Area < 2 m m D ia

R.H. ( 4 ou t o f 5 pane ls m u s t p as s ) £ 2 Spots 1-2 m m Di a Corrosiv i ty Test: (10 days, 80°F, 5 0$ R .H. ) No Corr. on 2 Spec.

3 spec. (B ras s cl ip a n d s teel d i sc) : orr. at 10X s 3 spots under cl ip; 1 Spec. Re c o m m e n d e d Operating Tem p ange, ° F : -65 to 35 0 NATO Symbol : None Storage Stabi l i ty : - - Compat ib i l i ty : — Synthetic Oi l B as e Carboxyl ic Acid Ester

Notes: , no in format ion . Report , no l imit , r ep o r t data.

Use: Lo w evapora t ion oi l fo r a i r c r a f t ins t ruments , elect i cal equipment an d m e c h a n i c a l equipment w h e r e wide tempera tu re an d ox ida t ion an cor rosion pro tec t ion ar e needed.

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AMCP 706-123

c. hemical omposition: This il s ynthetic base oil (carboxylic acid ester) with additives to impart oxidation stability and corrosion protection properties. It contains no pour point depressants or V.l. improvers.

d. imitations: The finished fluid must contain no resins, gums, rubber, fatty oils, oxidized hydrocarbons, or ther dditives ot pproved y he ualifying

agency. Containers fo r the fluid must have a warning note that this fluid may soften aint, atural ubber, or eoprene.

e. ustodians: Army-MR Navy-WP Air Force-11

MIL-L-7808G: UBRICATING IL , IRCRAFT TURBINE ENGINE, YNTHETIC BASE

(NATO ymbol: 0-148) a. eneral haracteristics: his il s onpe-

troleum base lubricating oil fo r aircraft turbine engines and similar equipment. t ha s good storage, wide temperature, nd nvironment imits.

b. sable mbient emperatures: The perating temperature ange s not pecified, ut he nominal operating temperature range is -65°F to 00°F.

c. hemical omposition: t hall e ynthetic base fluid (carboxylic acid ester) but additives to impart oxidation tability, orrosion-preventive roperties, and ntiwear properties are permitted.

d. ses: This oil is intended as a lubricating oil in specific models of aircraft urbine ngines, helicopter transmissions, nd similar equipment.

e. imitations: This oil should not be mixed with any ils ther han IL-L-7808 ils nd evisions thereto. If the oil contains tricresyl phosphate additive, the supplier must certify that it contains less than .0 percent of the ortho isomer.

f. ustodians: Army-MR Navy-WP Air orce-11

MIL-L-23699A: UBRICATING IL , IRCRAFT TURBOPROP AND TURBOSHAFT ENGINES, SYNTHETIC BASE

(NATO Symbol: None) a. eneral haracteristics: This il s onpe-

troleum ase il imilar o MIL-L-7808G but ith higher pour and flash oints.

b. sable mbient emperatures: he perating temperature ange s not pecified, ut he nominal range is 40° to +400T.

c. hemical composition: The composition of this synthetic base oil is not imited, except that metal organic ompounds f itanium re rohibited. he oil ay ontain ricresyl hosphate s an ntiwear additive.

d. ses: This oil ha s a higher viscosity than MIL- L-7808G and is intended fo r use in aircraft turboprop and urboshaft

ngines, helicopter ransmissions, nd

other ystems here IL-L-7808G as een used reviously.

e. imitations: Because of the higher viscosity, this oil may not be suitable below-40°F. f tricresyl phosphate ntiwear dditive s sed, t hall not ontain more han .0 percent of ortho somer. O il container should have the following note: "Do not mix oils other than MIL-L-23699 and evisions thereto".

f. ustodian: Navy-WP

MIL-S-81087A(ASG): SILICONE LUID, HLO- RINATED PHENYL METHYL

POLYSILOXANE (NATO Symbol: None) a. eneral haracteristics: This iquid s ual

class silicone base liquid for lubrication and other ap - plications over a wide temperature range. t has good thermal stability.

b. sable ambient emperatures: Type : n ir (oxygen) environment this fluid is suitable for-100° to 425°F usage. n an inert atmosphere this fluid is suitable for -100° to 00°F onditions. Type I: This luid contains an oxidation inhibitor and in both an air environment nd n nert tmosphere t s uitable or -100 °F to 00°F conditions.

c. hemical composition:Type I fluid is a copoly- mer ontaining only dimethyl siloxy and methyl chlo- rophenyl iloxy nits, with rimethyl iloxy erminal groups. Type II fluid is a Type I fluid with the addition of an oxidation inhibitor fo r high temperature stability in oxidizing atmospheres. Any other additives in either Type I or Type II requires prior approval of the qualify- ing agency.

d. ses: This liquid is used fo r lubricating, hydraulic, damping, and related applications over a wide temperature ange. pplications re : ydraulic ystems and ervomechanisms; rankcases nd gear boxes or

mechanical evices nd ompressors, ngines, nd pumps; ball, sleeve and pivot bearings in instruments; electronic equipment and lectric motors, tc.; locks and timing devices; nd fluid transmissions.

e. imitations: Type I luid, he n xposed o temperatures above 500°F in an inert atmosphere, as

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AMCP 706-123

MIL-L-7808G: LUBRICATING IL, AIRCRAFT URBINE NGINE,. YNTHETIC ASE

PROPERTIES VALUES

Color: Transparent, o. 3 STM Pour oint, F Max): -75

Flash oint, °F Min) (COC) 400

Viscosity, cSt: 100°F Min) 11.0

210°F Min) 3.0

Viscosity Stability, cSt: (3 r t 65°F) <13,000 (72 r t 65°F) <17,000

Additives: Oxidation nhibitor, wt Allowed Corrosion nhibitor, wt Allowed Antiwear Tricresyl hosphate), wt Allowed TCP, rtho somer ontent, $ wt £1.0

Acid No.: mg OH/g Max) 0.30

Evaporation: wt oss, f, Max); (6.5 r t 00°F) 35.0 Trace ediment: ml/200 ml Max) 0.005

Corr. and xid. Stability: Steel ±0.272 r t 47°F Silver +0.2 Max wt hg, Aluminum ±0.2 mg/cm^ Magnesium +0.2

Copper +0.4

Pitting, Etch, or Corr. at QX None Vise Chg t 00°F; -5 o 15 Acid No. Increase (Max) 2.0

Silver nd Copper Corr.; (50 r t 50°F), t oss; mg/in? £3.0 Lead Corr.: (l.O r t 25°F) t oss, mg/in? £6.0 Deposition o.: Average f est Max) 3.5

Individual est Max) 4.25

Rubber well: Syn. Type ; vol increase 12 o 5 Foaming: 75°F, in blowing, l oam Max) 25

75°F, in ettling, l oam Max) None 200°F, in blowing, l oam Max) 25

200°F, in ettling, l oam Max) None 75°F, in blowing, l oam Max) 25 75°F, in ettling, l oam Max) None

Storage tability: (2 ays t 30°F) ead Corr. alue, mg/inf

£25

(7 ays t 30°F) ead Corr. Value, mg/in? £150

12 months, 75°F, dark oom No eparation nd pec. Test100-hr ngine est: Engine ating (Min) 2.83

Filter wt ncrease; b/hr Max) 0.020 Average Oil onsumption; b/hr Max) 1.25

Compatibility: (Oils o his pec and others) MIL-L-25336 MIL-L-9236 MIL-C-8188

MIL-0-6081 (Grade 010) Load Carrying (Ryder ear est): % Ref Oil B" £68.0

NATO ymbol: 0-148 Recommended Operating emp Range, F: -65 o 300 Synthetic il ase: Carboxylic Acid Ester Use: Specific ircraft urbine ngines, elicopter ransmi ssions nd imilar ystems.

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A MC P 706-123

MIL-L-23699A: LUBRICATING IL, IRCRAFT URBOPROP AND URBOSHAFT NGINES, SYNTHETIC BASE

PROPERTIES VALUES

Color: NR Pour oint, °F (Max): -65 Flash Point, °F (Min): 450 Viscosity, cSt: -40°F (Max) 13,000

100°F (Min) 25

210 °F 5.0 - .5

Viscosity Stability: (72 r t -40°F, $ hg)(Max) 6.0 Neutralization r cid o.: mg OH/g (Max) 0.50 Fluid Composition Syn.; o imit

Additives: Metalorganic itanium ompounds None TCP ortho isomer ont.) fc s 1.0

Evaporation: 6.5 r t 00°F, $ t oss (Max) 10.0 Trace ediment: 7 days t 75°F, l/200 l (Max) 0.005

Lead Corrosion: 1.0 r t 25°F, t Loss, mg/in? (Max) 6.0 Rubber well: "H" Syn., 72 r t 58°F, i ol 10 - 25

"F" Syn., 72 r t 400°F, $ ol 10 - 25 Foaming: (a) 75°F, .0 in blowing, ml Max) 25

75°F, 1.0 in ettling, ml Max) None (b) 200°F, 5.0 in lowing, ml (Max) 25

200°F, 1.0 in ettling, ml (Max) None (c) Repeat Sequence (a) Same s (a)

Storage tability: 48 r t 30°F, g/in? (Max) 25.0 (Lead Corr., t oss) 168 r t 30°F, mg/in? (Max) 150.0 Low emp torage: 6 k t °F Noncryst., nongel Extended torage: 12 onth t 5°F All pec. Tests Thermal tability: (24 r t 00°F), 100°F ise chg, $ S .0

Neutralization o. chg (Max): 2.0 Corr. & xid. Stability: Steel ±0.2/±0.2/Report

72 r t 75°F/400O F/425°F Silver ±0.2/10.2/Report

wt chg; mg/cm^ (Max) Aluminum +0.2/+0.2/ReportMagnesium t0.Z/t0. 2 /Report

Copper -0.4/+O.8/ReportViscosity hg. f -5 o 5/-5 o 5/Report

Neutralization o. chg, $ 2.0/3.0/ReportSludge fter 00°F est,

g/100 ml (Max) 1.0 Load arrying; yder ear est: f, ef. Oil "B" (Min) 88.0 Bearing est: Deposit emerit ating (Max) 80.0

(100 r t 80°F) Filter Deposit, g (Max) 3.0 Viscosity hg t 00°F, f -5 o 5 Neutralization o. chg Max) 2.0 Total Oil onsumption, l Max) 2000

Shear tability: (Sonic), 30 in t 0C°F; Vise, chg, $ Max) -4.0 Turboprop ngine Helicopter rans. Test: Select y ual. gency NATO ymbol: None Recommended Operating em p ange, °F: -40 o 00

Notes: NR, no equirements. Report, no limits, ut ata eported.

Use: Aircraft urbojet ngines, helicopter ransmissions, and 1 ;her ystems requiring igh performance lubricating oils.

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AMCP 706-123

MIL-S-81087ACASG): SILLCONE LUID. CHLORINATED HENYL ETHYL OLYSILOXANE

TYPE TYPE I

PROPERTIES VALUES VALUES

Color: SGardner td. Dark Amber r No. 1 Brown

Specific Gravity (77°/77°F): 1.03 o .06 1.03 o .06

Pour oint, °F Max): -100 -100 Flash nd Fire oint, °F (Min) 550 and 640 550 and 40

Viscosity, cSt: -65°F Max) 3,500 3,500 100° F (Min) 50 50 210°F Min) 15 15

Additives: Oxidation nhibitor None Required Others Approval Req'd. Approval Req'd.

Acid or Neutralization No.: g OH/g (Max) 0.05 0.10 Volatility: 24 r t 02°F, < f, vt, oss (Max) 1.0 1.0 Ge l ime (Honflow): 482°F, hr (Min) 72 1,500 Lubricity Shell -Ball): AISI 2100 (Grade ), 77°F,

600 pm, 50 g, 1.0 r; Scar Dia., m Max) 0.60 0.60 Oxid. Corr. Stability: Aluminum Alloy ±0.10 ±0.10 72 r t 00°F (Type ) St Steel, Type 25 ±0.10 ±0.10 and 00°F Type I): Titanium ±0.10 ±0.10 Max wt hg, g/cm 99.9 node ilver to. 10 ±0.10

Mild Steel ±0.10 ±0.10 Vise chg t 00°F, Max) 10 30 Acid Ho. Increase: (Max) 0.20 0.40

Solid Particle ontent: Particle ize, 0-20 Micron 2000 2000 20 l ample, ax 21-40 " 300 300 number f particles 41-80 " 80 80

81-100 " 40 40 101-150 " 20 (No 20 (No

Metal) Metal) over 50 " 0 0

Compatibility: W o ther ub. or No ther ub. or hyd. oil or yd. oil

NATO ymbol: None None Storage tability: -- -- Recommended Operating emp Range, F: (Air) -100 o 25 -100 o 00

(inert) -100 o 00 -100 o 00 Foaming: NR NR Rubber well: HR HR Hotes; —, no nformation.

NR, no equirement. Use: Lubrication, ydraulic ystems, damping nd transmiss ion luid, tc., over wide

temperature ange.

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AMCP 706-123

a tendency for the oxidation inhibitor to separate forming a soft gelatinous sludge or precipitate which will not decrease ubricity, but may ause pressure drop n systems having filters or small orifices. Type II should be reserved for severe and relatively continuous oxidizing environments. Neither type should be mixed with an y other lubricating oil or hydraulic fluid. When re - placing another oil with this fluid, parts must be disassembled and cleaned with solvents,

f. Custodian: Navy-WP

VV-D-001078(GSA-FSS): DAMPING LUID, ILI- CONE BASE (DIMETHYL POLYSILOXANE)

TO Symbol: Grade cSt) S-1714 10 S-1718 50 S-1720 100 S-1724 7,500 S-1726 20,000

S-1728 100,000 S-1732 200,000 a. eneral haracteristics: This pecification n-

cludes dimethyl polysiloxane base damping fluids having a wide range of viscosities-from 0.65 through 200,- 00 0 cS t at 77°F. The wide viscosity range of these fluids permits them to have many applications. This specification upersedes IL-S-21568A hich overed similar class of damping fluids.

b. sable emperatures: These luids re sable from-65° o 00°F depending n he pour nd lashpoints, nd upon he viscosity grade selected.

c. hemical omposition: These ilicone luids-

based on dimethyl polysiloxane-must be of high quality, meet the requirements of this specification, be free of suspended matter and water or sediment, nd contain no dmixture of other luids which re not p- proved.

d. ses: These multi-grade fluids are intended fo r many se s uch s damping fluids, ransducer fluids, lubricants, heat ransfer fluids, dielectric luids, mold release agents, water repellents, hydraulic fluids, protective dressings, nd impregnants.

e. imitations: These luids hould not e mixed with an y other type of lubricating oil or hydraulic fluid. When replacing another oil with this fluid, parts must

be disassembled and thoroughly cleaned with fresh solvent. Consideration must be given to the type of elastomer used in contact with the fluids because they tend to cause certain elastomers to shrink and harden. This is particularly true of the lower viscosity fluids.

f. ustodian: Navy-WP

MIL-H-5559A(WEPS): HYDRAULIC LUID, R- RESTING GEAR

(NATO ymbol: None) a. eneral characteristics: This pecification ov -

ers the requirement for on e type and on e grade of nonpetroleum base hydraulic luid ontaining wo corrosion nhibitors.

b. sable emperatures: A s n ndiluted iquid, this luid as mbient emperature imits rom °F (freezing point) to approximately 329°F (boiling point). Lower freezing point temperatures may be obtained by the addition of water.

c. hemical composition: This liquid ha s an ethylene glycol base and contains two corrosion inhibitors- triethanolamine phosphate and sodium mercaptoben- zothiozole.

d. ses: This liquid is intended primarily for use in aircraft arresting gear and imilar hydraulic systems.

e. imitations: This iquid s not nterchangeable with an y other type or grade of hydraulic fluid. Care

may be required in packaging to prevent deterioration or damage during hipment or storage under normal environmental onditions ince ndiluted luid ill freeze at about 0°F.

f. ustodians: Navy-WP Air Force-11

MIL-P-46046A(MR): PRESERVATIVE FLUID, AU- TOMOTIVE BRAKE SYSTEM AND COMPONENTS

(NATO ymbol: None) a. eneral characteristics: This pecification ov -

ers ne type, ne rade, nd hree ompositions of a

castor oil base preservative hydraulic fluid. b. sable ambient emperatures: Temperature i- mits as a preservative fluid are not specified, but as limited usage heavy duty brake fluid, it should be limited o emperatures bove °F nd o moderate li- mates.

c. hemical composition: This castor oil base hy - draulic fluid is prepared in three compositions containing different additives. Composition ontains a dilu- tent 3-methoxy butanol-1), borax-glycol ondensate, and an approved antioxidant. Composition 2 contains a ilutent ß, ß'-methoxy-methoxy thanol), orax- glycol condensate, and an approved antioxidant. Com-

position ontains dilutents (diethylene glycol mono- methyl ther nd thylene lycol monobutyl ther), borax-glycol ondensate, i-t-butyl-p-cresol, nd - cresol.

d. ses: This luid s ntended or preserving u- tomotive hydraulic brake systems of vehicles in storage.

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W-D-00107S GSA-FSS):

DAMPING FLUID, SILICONS B A S E (DIMETHYL POLYS ILOXANE)

Vi s c o s i t y G r a d e s , cS t ,

at 25° C (77°F) Te s t Method

Vi s c o s i t y -

t e m p e r a t u r e (VTC)

c o e f f i c i e n t t0 .02

S p e c i f i c g r a v i t y

+0 .004 at

77°F/77°F

R e f r a c t i v e i n d e x

io .002 at 77° F

Pour Point ,

'F , Ma x

D i e l e c t r i c c o n s t a n t

+0 .03 at 100 c y c l e s

an ä 73°F

F l a s h po in t , °F,

Min

Vo l a t i l i t y, %, Max

N e u t r a l i z a t i o n No. , mg KOH/g

NATO S y m b o l

Storage roperties

Recommended Operating em p F

0.761

Foaming

210° F

0.58 0.62 0.61

1.402 1.4035 1.4035

0.61

0.976

1.4035

0.61 100° F

325 535

2.0 2.0

ASTM 298

ASTM 747

Fed. Test ethod Std. No. 791a; Method o. 201

ASTM 50

Fed. Test ethod Std. No. 791a;

Method o. 1103

Wt oss; 4 r at 02°F

- - S-1714

- -

S-1718 S-1724 S-1724

Ref. Pour oint Max) and lash oint Mi

S-1725 S-1728 S-1732

no in fo rmat ion .

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AMCP 7 0 6 1 2 3

MIL-H-5559A(WEPS): HYDRAULIC FLUID, ARRESTING GEAR

PROPERTIES VALUES

Color: Specific Gravity, 60°/60°F : (undi luted) Freez ing Point, ° F : (Undi lu ted) Boil ing Point, ° F (Min) : (Undiluted) Composition: thy lene Glyco l , % w t (Min)

Water, # w t Tr ie thano lamine Phosphate , $ wt Sodium Mercap tobenzo th iazo le , $ wt

Phosphate Content (ca lcu la ted as H3PO4), $ w t (Min) Ash, $ w t (Max) : Viscosi ty, cSt: 100°F (Min) pH Value (50$ aqueous so l . ) , 77°F : Suspended Matter: Storage Stability:

Recommended Opera t ing Temp

ange, ° F : Foaming:

Oxd. a n d Corr. Stabi l i ty : NATO Symbol: Compatibility: Rubber Swell:

NR 1.111 to 1.123

~ 0 329

93.95 2. 5 to 3. 0 2.25 to 2.75 0.2 to 0.3 0.56 0.52 9. 0 7.2 to 7.8

None H R

0 - 329 KR NR

None No other type or grade

NR

Notes : NR, no requirements.

Use: A i r c r a f t ar rest ing gear an d s imi la r hydrau l ic sys tems .

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AMCP 706-123

It is also a packaging fluid fo r both wheel and master cylinder assemblies. The fluid may also be used as an actuating luid n est tands n hecking ydraulic brake parts or laws nd efects. t ay e se d in vehicles n imited operation in moderate an d warm climates.

e. imitations: Avoid prolonged breathing of vapors from hese fluids and se with dequate entila- tion. lso void epeated r rolonged ontact with kin.


JAN-F-461: FLUID, SHOCK ABSORBER, HEAVY

(NATO Symbol: None; Military Symbol: SAH) a. eneral characteristics: This pecification ov -

ers a chemically treated, castor oil base liquid fo r rotary type hydraulic shock bsorbers.

b. sable emperatures: The pecific emperature limits fo r this liquid are not specified but the pour point

(maximum) is-25°F and the flash point (minimum) is 400°F. Because of viscosity haracteristics, he iquid will function best at emperatures bove ° nd e - low 200°F.

c. hemical composition: This liquid is a castor oil chemically reated o produce proper haracteristics. The liquid shall be free of acid, alkali, moisture, arry or suspended matter, and other foreign matter. t may not ontain an y osin or cottonseed il.

d. ses: This liquid is specifically intended for use as eavy hock bsorber luid n Houdaille otary- type shock absorbers. t also may have some usage as a damping or hydraulic actuating fluid.

e. imitations:This liquid is no t recommended fo r low emperature applications. f. ustodians: Army-MR

Navy-SH

MIL-H-13910B: HYDRAULIC LUID, OLAR- TYPE UTOMOTIVE RAKE, ALL-WEATHER


ers ne ype nd ne grade of automotive hydraulic brake fluid or low temperature applications.

b. sable emperatures:-^ 0 to +131°F ambient. c. hemical omposition: This pecification oe s

not imit the composition of this hydraulic fluid. d. ses: This iquid s ecommended s n ll-

weather utomotive hydraulic brake ystem luid or ambient emperatures ranging from-67° to 131°F.

e. imitations: It should no t be used in preserving hydraulic rake arts nd omponents n are- house torage.

f . ustodian: Army-MR

VV-B-680a: BRAKE FLUID, AUTOMOTIVE

(NATO Symbol: H-542; Military ymbol: HB) a. eneral characteristics: This pecification ov -

ers on e rade and type of hydraulic brake fluid. b. sable emperatures: Usable ambient empera-

ture range of -40° to +13TF and usable operating liquid emperatures from-40° to 374°F. n practice, low operating limit of-31°F is recommended. The viscosity at-31°F will be about 90 0 cSt.

c. hemical composition: Composition of this fluid is not imited; owever, o meet he pecification e- quirements t will probably e necessary o employ glycol or castor oil and glycol base fluid and approved additives.

d. ses: This brake fluid is intended for use as an operating luid n utomotive hydraulic rake ys - tems within he pecified mbient r luid emperature imits.

e. imitations: This fluid is not to be used for preserving hydraulic brake system parts and components in torage, nor as n operating luid n ehicle brake systems when the vehicle may be subject to prolonged standby torage.

f . ustodians: Army-MR Navy-YD Air Force-67

MIL-H-22072A(WP): HYDRA ULICFL UID, CA TA - PULT


ers a fire-resistant water base hydraulic fluid containing additives fo r ubricity, orrosion prevention, nd iscosity-temperature characteristics.

b. sable ambient temperatures: Specification does not limit temperature range of this hydraulic fluid but, because of the high water content, it should be used fo r moderate ambient temperatures within the low temperature crystallization ( + 10°F) and the high temperature stability + 158°F) ange.

c. hemical omposition: This pecification oe s not limit the composition of this hydraulic fluid other than hat t must ontain 0 percent water and additives for lubricity, corrosion, and viscosity-temperature characteristics tp meet the specification requirements.

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A MC P 706-123

JAN-F-461: FLUID, SHOCK ABSORBER, HEAVY

PROPERTIES VALUES

C o l o r :

S p e c i f i c G r a v i t y :

B a s e Flu id : A d d i t i v e s : c i d s

AlkaliMoisture

Suspended Matter

T h i c k e n e r s R o s i n

Cottonseed Oi l Pour Po in t , ° F: Max)

F l a s h Po in t , ° F: (Min ) Vi s c o s i t y, SUS: 100°F (Max )

210° F Neutralization N o . : g K O H / g (Max )

Copper S t r i p C o r r. : h r at 212°F

R e a c t i o n : eutrality ( Q u a l i t a t i v e ) S t o r a g e S t a b i l i t y :

C o m p a t i b i l i t y :

Recommended Ambient Temp R a n g e , ° F: R u b b e r Swel l :

F o a m i n g : NATO S y m b o l : Military S y m b o l :

NR

HR C a s t o r Oi l

H o n e None

None None

None

None N o n e

-25

4 00 1 , 5 0 0

140-150 3. 0

No C o r r o s i o n Neutral ( Ye l l o w )

None S AH

N o t e s : H , no r e q u i r e m e n t s .

--, no i n f o r m a t i o n .

U s e : otary t y p e ( H o u d a i l l e ) s h o c k a b s o r b e r s a n d as a d a m p i n g o r h y d r a u l i c f l u i d .

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AMCP 706-123

MIL-H-13910B: YDRAULIC FLUID, POLAR-TYPE AUTOMOTIVE BRAKE, ALL WEATHER

PROPERTIES VALUES

Solor: H R Speci f ic Gravi ty : NR Pour Point, ° F : <-67 Boi l ing Point, ° F ( M i n ) : 309 Boi l ing Point Change, ° F ( M a x ) : +5 Flash Point, ° F ( M i n ) : 14 5 Viscos i ty, cSt: -67°F (Max) 900

122°F (Min) 3. 5 212°F (Min) 1. 3

pH Value: ( f lu id -water-a lcoho l mixture) 8.0-11.0 Evaporation: ( 7 day, 212°F cycle) $ wt Loss (Max) 80

Residue, Qual i ty Fluid & Oily Precipitated Matter Slight, Nongr i t ty Residue Proper t i es , Pour Point, ° F (Max) 27 Viscos i ty, cSt: 0° F (Max) 2,100

122°F (Min) 35 212°F (Min) 9

Low Temperature , Appearance : Tr a n sp a r e n t (144 h r at -67°F) Bubble Rise Time, s ec (Max) 10.0 Fluid-Water Mixture: (2 4 hr at -67°F) Bubble Rise, s ec (Max 5 . 0

(24 hr at 140°F) Appearance No Separa t ion or Sediment Rubber Swell : (120 hr at 158°F), Cup di a increase; i n . 0.015 to 0.050

Hardness ch g (durometer) : oints -10 to +0 Rubber Condition Ho Disin tegra t ion

Corros iveness : Tinned I ron 0.2 120 h r at 212°F arbon Steel 0.2 Ma x w t c h g , Aluminum Alloy mg/cm Cast I ron

0. 1 0.2

B r a s s 0. 4 Copper 0. 4 P i t . & Etch, on Metal St r ips Hone Rubber Cup Condition

Ho Disin tegra t ion Ma x Cu p di a increase, i n . 0.050 Rubber hardness ch g (durometer) points <-15 pH Value (Tes t Fluid) 8. 0 to 11.0 Prec ip i ta ted Mat ter, $ vo l (Max) 0.05

Simula ted Service: e ta l Pit tc h Gall ing Sl ight 232,500 s t rok ing cycles Piston o r Cy l ia chg (in .) SO.005 Temp 6 7 ° to +158°F Rubber Cu p Di a ch g (in .) £+0.035

Rubber Cup Li p In terference, % £ 65 Rubber Hardness chg (durometer)

Points S10.0 Rubber Cup Swell , Scuff ing ,

Crack, etc. Modera te Ma x Pressure ch g in 12 hr

period , ps i +3 5 to -5 0 Fluid, Vo l Loss 24 h r (ml / l , 000

St rokes) s i . 5 Flu id Leakage; 100 cycles at

5 00 ps i ; m l (Max) 36.0 Flu id Sediment, % vo l (Max) 1. 0

Compatibility: Al l Spec. Fluids

(cont 'd next page)

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AMCP 706-123

MIL-H-L59IOB: HYDRAULIC LUID, POLAR-TYPE UTOMOTIVE RAKE, ALL WEATHER (cont'd)

PROPERTIES VALUES

Stability: Aluminum Alloy 72 r t 7°F nd 68 hr t 158°F Cast ron Max vt Loss, mg/cm?

N A T O Symbol: Recommended perating emp ange, °F :

Foaming: Storage tability:

Pit r Etch Gum Deposit

0.05 0. 3

M o d e r a t e

M o d e r a t e N o n e

-67 to +1 3 1

NR

N o t e s : R, no r e q u i r e m e n t s . --, no i n f o r m a t i o n .

U s e : utomotive h y d r a u l i c b r a k e s y s t e m s . No t recommended as p r e s e r v a t i v e f l u i d f o r s t o r a g e .

4 5 1

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A MC P 706-123

W-B-680a: BRAKE FLUID, AUTOMOTIVE

PROPERTIES VALUES

Color: HR; ransparentSpecific Gravity: NR Pour oint, °F Max): <-58

Boiling oint, F (Min): 374 Boiling oint hange, °F Max) ±5.4

Boiling oint Compatibility, F Max): ±9.0 Flash Point, F Min): 179.6

Viscosity, cSt: -31°F Max) 900

122°F (Min) 3.5

212°F Min) 1.3pH Value:(fluid-water-alcohol mixture) 7.0 o 1.0 Evaporation: (7 ays t 12°F ycle), wt oss (Max) 80

Residue, Quality Fluid Oily Precipitated Matter Slight; on-gritty Residue roperties, Pour oint, F Max) <23 Viscosity, cSt: 32°F Max) 7,000

122°F Min) 35 212°F Min) 10

Low em p Properties: Appearance Transparent6 r t 58°F, ubble ise ime, sec

(Max) 35 2 r t 40°F, ubble ise ime, ec

(Max) 10 Fluid-Water Mixture: 24 r t 40°F, ubble Rise, sec (Max) 10

24 r t 40°F, appearance No tratification Rubber well: (120 r t 58°F), Cup ia ncrease (in.) 0.006 o .050

Burometer hg, at 58°F, oints S-10 o 0 Durometer hg, at 48°F, oints £-10 o 0 Rubber ondition No Disintegration

Corrosiveness: Tinned ron 0.2

120 r t 12°F Carbon teel 0.2Max wt hg, g/cm Aluminum Alloy 0.1

Cast ron 0.2Brass 0.4Copper 0.4Pit or tch of Metal trips None Rubber up ondition No Disintegration Max up ia ncrease, n. 0.05Rubber ardness hg durometer)

Points <-15pH alue (Test luid) 7.0 o 1.0 Precipitated Matter, vol Max) 0.05

Simulated ervice est: Metal Pit., tch, or Galling None 300,000 troke ycles Piston or yl. dia hg (in.) SO.005 Temp from 7° to 48°F Rubber up ia hg (in.) s+0.035Pressure 00-1,000 si Cup ip ntef., # S65.0

Rubber up urometer hg (Points) S15.0

Rubber up well, Scoring, Crack, tc. Moderate

M& x ressure hg n 2 r, si +35 o 50 Fluid Loss in 24,000 ycles,

ml (Max) 36.0 (cont'd ext age) Fluid ediment, > vol (Max) 1.5

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AMCP 706-123

VV-B-680a: B R A K E LUID, UTOMOTIVE cont'd)

PROPERTIES VA E U E S

C o m p a t i b i l i t y :

S t a b i l i t y : 72 h r at 7 7 °F a n d 168 h r

at 1 5 8 ° F, Max wt L oss , mg/cm

NATO S y m b o l :

Military S y m b o l :

R e c o m m e n d e d A m b i e n t Temp R a n g e , °F :

R e c o m m e n d e d F l u i d Te m p Ran g e , °F : F o a m i n g :

S t o r a g e S t a b i l i t y :

Aluminum Alloy

C a s t I r o n Metal Pi t o r Etch

Gum D e p o s i t

All Spe c . F l u i d s

0.05 0. 3

H o n e

N o n e H - 5 4 2

H B -3 1 to 13 1 -3 1 to 37 4

KB

N o t e s : NH , no r e q u i r e m e n t s . --, no i n f o r m a t i o n .

U s e : O p e r a t i n g h y d r a u l i c f l u i d f o r a u t o m o t i v e b r a k e s y s t e m s a n d s i m i l a r s y s t e m s . o t r e c o m m e n d e d f o r s t o r a g e o r s t a t i o n a r y s y s t e m s .

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AMCP 706-123

MIL-H-22072A(WP): HYDRAULIC FLUID. CATAPULT

PEOEEETIES VALUES

Color: Red

Specific Gravity: 68°F 1.04 o .06

Pour oint, °F (Max): NR

Flash Point, °F (Min) : NR Cloud oint, °F (Min) : 210

Compression gnition: 140°F t ,000 si None Viscosity, cSt: 0°F (Max) 1,760

100° F 40.72 o 45.0 130°F Min) 21.7

Evaporation: 4 r t 58°F Not ard r esinous Volatility: 30 in t 0-80°F, $ wt oss (Max) 10.0

Composition: Not imited Fire Resist.) Water Content, wt 50 .5

Lubricity Additive, f> wt Permitted

Corrosion nhibitor, $ wt Permitted Viscosity-Temperature Improver, f> wt Permitted

Foaming: 5 in lowing t 5°F, ml Max) No imit - eport 10 in ettling t 5°F, l Max) 10.0

pH Value:(fluid-water mixture) 8.8 o 9.2

High emp tability: 168 r t 58°F No hemical hange Low em p tability: 6 r t 0°F No Crystallization Effect n ackings: 0-Ring, 168 r t 158°F; % ol hg -5.0 o +10.0 Effect n Other Elastomerics: Std. Cond. Negligible Corrosion (Static) Steel 0.4

720 r t 58°F Naval rass 0.4M ax wt oss, g/cnr Manganese ronze 0.4

Copper 0.4

Pit r tch Max) Slight Fluid olor hg None Separation r ludge None

Corrosion Stirring) Steel 0.7 336 r t 58°F Copper 0.7 M ax t oss, mg/cm S Pit r tch (Max) Slight

Fluid olor hg None Separation r ludge None

Storage tability: 12 onth t 7°F Satisfactory Pump est: 500 r, Mod. Vickers Satisfactory Compatibility: All pec. luids Toxicity: No pecial andling NATO ymbol: None Recommended mbient em p Range, °F:

_

Notes: NR, no equirements.

—, no information. Report, no limits, but eport data.

Use: Fire esistant fluid or ower ransmission or ydraul Lc systems such s

ircraft catapults.

4-54

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AMCP 706-123

d. ses: A fire resistant water base liquid intended as ower ransmission edia or ydraulically actuated ystems such s atapults for launching Naval ircraft.

e. imitations: Not recommended for either low or high temperature applications. Liquid will soften most commonly used paints. No special handling procedure

is equired. f. ustodian: Navy-WP

4-7

ISCOSITY-TEMPERATURE GRAPHS

The ages which ollow present ASTM Viscosity- Temperature graphs of the hydraulic fluids discussed in the preceding paragraphs. Where possible, data of typical iquids produced y various manufacturers were

used to generate the graphs. These graphs are included in igs. -1 hrough 4-10. When manufacturers' data were not vailable, he graphs show he pecification requirements. These graphs are included in Figs. 4-11 through 4-13.

Liquids not dentified with hemical designation are petroleum or petroleum-base liquids.

Graphs of the following liquids are not included be - cause ommercial ata ere ot vailable nd/or specification requirements were not sufficient to plot a curve (i.e., iscosity was limited at only on e temperature or the specification was for a family of liquids of various viscosities):

MIL-H-46001A MIL-L-17331D VV-D-001078 MIL-H-5559A MIL-P-46046A JAN-F-461

4-55

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AMCP 706-123

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8/11/2019 884519


A MC P 706-123

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4-58

8/11/2019 884519


AMCP 706-123

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4-59

8/11/2019 884519


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AMCP 706-123

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4-61

8/11/2019 884519


AMCP 706-123


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4-62

8/11/2019 884519


AMCP 706-123


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4-63

8/11/2019 884519


AMCP 706-123

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4-64

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4-65

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AMCP 706-123

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4-66

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AMCP 706-123


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8/11/2019 884519


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4-68

8/11/2019 884519


AMCP 706-123


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AMCP 706-123

CHAPTER

ADDITIVES

5-1 GENERAL

Formally efined, n dditive or hydraulic luids and lubricants is a compound or component hat n- hances some property of, or imparts some ne w property to, he ase luid. A ase tock hydraulic luid hat cannot meet requirements for operation in a given hydraulic system frequently can be modified through the use of additives in such a way that the range of satisfactory operation of the ase iquid an e xtended o meet more severe requirements. n the formulation of a hydraulic fluid, additive components may constitute from less than on e to as much as 20 percent of the final liquid composition. The more important classes of ad - ditives nclude oxidation nhibitors, orrosion nhibitors, iscosity ndex mprovers, oa m nhibitors, nd lubricity dditives.

In he election of additives nd ormulation of a fluid, ach additive must be compatible with the ase stock, other additives, and system components. Exam- ples of problems of compatibility that can be encountered re ited hroughout his hapter. olubility of

additives in the base stock is an important limitation in the se of some additives at low temperatures.

Although general theories ca n be developed for the mode of action of different kinds of additives, an effective additive in on e hydraulic fluid may not be equally effective n nother. he ange of conditions hat hydraulic fluid may encounter during storage and use will determine the selection of additives. Therefore, the formulation of a hydraulic fluid must take into account a wide variety of factors, and the effectiveness of each additive must be verified experimentally. Several of the common hydraulic luid hortcomings, nd he ech- nology and additives developed to compensate fo r them

are discussed n he remainder of this chapter.

5-2 XIDATION NHIBITORS In environments that contain even small amounts of

oxygen, he oxidation tability f ydraulic luid

limits ts seful ife s well s ts upper temperature limitation. Therefore, dditives or nhibitors hat n- crease he esistance f he luid o he hemical changes associated with oxidation are very important. Ultimate changes that may be encountered as a result of oxidative deterioration include changes in viscosity; the precipitation of insolubles, including lacquers and varnish; nd an ncrease in cidity and corrosiveness. In a consideration of the oxidative stability of a hydrau-

lic luid, ccompanying orrosion ffects hould not, and usually are not, be considered independent of oxidation. For this reason, laboratory screening of oxidation inhibitors usually also considers changes in acidity of the hydraulic fluid and the corrosion of metal samples n contact with he fluid.

5-2.1 MODE OF ACTION OF ANTIOXIDANTS

In order to properly consider the mode of action of antioxidants, some knowledge of the mechanism of ox - idative degradation s ecessary. Liquid phase xidation is considered a free radical process undergoing the

usual steps of initiation, propagation, and termination. Schematically, after the process has been initiated, the course of oxidation in petroleum oils ca n be represented as ollows: RH * R- + « RH 0 2 * R« O O ' | nitiati nitiation H = hydrogen

O = oxygen

of

u = oxygen R • + 2 » ROO •

R O O - +' RH - ROOH - Pro Pa Satlon R = a portion

lubricant molecule

2ROO •-+ nactive Products Termination •= an electron

Initiation eactions n ubricants re most often hermally activated but may also be induced by light, ioniz- ing adiation, or other means. ince he propagating species (R-) ca n be continuously regenerated, the process s hain eaction. ermination ccurs ith the ormation of nonradicals uch s lcohols, lde- hydes, etones, nd lefins, hich re lso usceptible to oxidation nd ay roduce cids, ludge,

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and arnish. t levated emperatures, he ntermediate hydroperoxide an decompose nd produce additional adicals:

ROOH RO HO 2 ROOH RO + ROO- H20

Since the concentration of radicals present can increase with

time, oxidation

is autocatalytic. Also,

when

acidic materials re ormed n hydraulic luid which s n

contact ith etals s onsequence f oxidation, metal corrosion can occur with the formation of metal ions, hich an ecome oluble n he luid. hese metal ions-particularly those of iron, lead, and copper- are catalysts in the oxidation process. The stable shelf life under oxidative conditions of di-2-ethylhexyl sebacate at 347T (175°C) in the presence of various metals illustrates this catalytic effect: no catalyst, 25 hr; copper, 0 hr ; opper-beryllium, 0 hr ; teel, 15 r; nd aluminum, 20 hr (Ref. ).

Although metal ions are pro-oxidants at lower temperatures in hydrocarbon liquids, they can function as antioxidants in higher temperature fluids such as silicones, henyl thers, nd luoroesters Ref. ). t higher temperatures in these fluids, the metal ions presumably alter the course of the hydroperoxide reactions and produce nonradical products.

5-2.2 CLASSES OF ANTIOXIDANTS A N D SYNERGISM

Antioxidants re effective n ne of three ways-(l) metal deactivators minimize the catalytic effect oftrace amounts of metal on s n he luid; 2) ree adical acceptors break the chain reaction in the propagation step; and (3 ) hydroperoxide destroyers inhibit the formation of free radicals in the hydroperoxide decompo- sitions. A combination of antioxidants that may serve several of these purposes may be used.

5-2.2.1 Metal Deactivators

The metal deactivators most commonly used are se- questering r helating gents. hese nclude ,N- disalicylidene diamine, ercaptothiadiazole, uiniza- rin, nd alizarin.

Hindered phenols-such s 2,6-ditertiary-butyl-4-meth- ylphenol and aromatic amines such as phenyl- 1-naphthylamine-are ery effective.

5-2.2.3 Hydroperoxide Destroyers

A variety of sulfur, elenium, nd phosphorus-containing compounds can function as hydroperoxide de - stroyers. ffective aterials nclude henothiazine, phosphorus pentasulfide-olefin reaction products, zinc dialkyldithiophosphates, sulfurized olefins, alkyl polysulfides, dialkylphosphonates, trialkyl phosphites, zinc dialkyl dithiocarbamates, alkyl trithiocarbamates, and alkyl selenides. Phenothiazine is particularly useful at higher temperatures.

5-2.2.4 Synergism

The ombined ffect of tw o or more nhibitors s

often reater han he um f the ffects of the n- dividual inhibitors. This synergistic effect has led to the common practice of employing tw o or more oxidation inhibitors. Not only can synergism occur through the reinforcement of inhibitors through their effectiveness in different phases of the oxidation mechanism, but also by the second inhibitor regenerating the first. For example, synergistic effects observed at 150°C when dialkyl phosphonates are used with sterically hindered alkyl henols re ttributed o he hosphonates transferring hydrogen to the oxidized phenols (Ref. 3).

5-2.3 EXAMPLES OF TH E US E OF INHIBITORS IN VARIOUS FLUID LUBRICANTS

The ffectiveness of various lasses of materials s oxidation nhibitors n ifferent inds f hydraulic fluids nd ertain problems ttendant with heir se can e llustrated y he esults f ecent esearch. Since oxidation ates ncrease apidly with emperature, nhibitors seful t igher emperature av e received considerable attention.

5-2.3.1 Esters

5-2.2.2 Free Radical Acceptors

Amines and phenols are most commonly used as free radical acceptors and are effective in many base stocks.

Ester fluids can be inhibited against oxidation to at least 212°F (100°C) with 0.1 o 0.2 percent of the usual phenolic nd romatic mine ntioxidants Ref. ) which are also commonly used in petroleum oils.

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A number of inhibitors have been examined for use with esters at higher temperatures. Phenothiazine and its derivatives are usually effective to 350T (175°C) but lacquer ormation ha s been observed t 25°F(163°C). Phenyl-1-naphthylamine s he os t ffective of the aromatic amines and as n upper emperature limit of 25°F (163°C). -alkyl elenides re ffective t

325T 163°C), ut he nalogous sulfur compounds have n pper emperature imit f 57°F (125°C). Phosphites, which re ffective o 12°-257°F(100°- 125°C), re imited y heir hydrolytic usceptibility and volatility. Except or erious opper corrosion t 325°F (163°C), -terf-butylphenyl-2-mercaptothiazole provides dequate inhibition. The zinc complex of di- butyldithiocarbamate and dibutylamine functions satisfactorily at 30 2 °F 150°C) Ref. ).

Phenothiazine ubstantially xtends he nduction period at 350°-400°F (175°-205°C) and reduces the rate of oxidation at 00°F (375°C). However, t the higher temperature,

phenothiazine,

as well

as other

amine

inhibitors, auses darkening nd the formation of trace dirtiness in the liquids (Ref. ).

At 425° and 500°F (218° and 260°C), the most effective elenides or nhibiting xidation re />-amino- phenyl phenyl elenide, 5-dimethylaminobenzo(2,l,3) selenadiazole, nd iphenyl iselenide. The selenides have een ound o e orrosive o opper, ilver, magnesium, and aluminum at selenium concentrations of 0.5 percent Ref. ).

5- ethyl-10,10- diphenylphenazasiline 5-10-10) s useful n nhibiting ster ase tocks t 00°-500°F

(205°-260°C). ince a certain hermal level is required to activate 5-10-10 as an antioxidant, it is best used in combination with a low temperature antioxidant. Mix- tures of 5-10-10 and phenyl- 1-naphthylamine are effective (Ref. ).

5-2.3.3 Silicon-containing Fluids

Diarylamines are effective antioxidants in siloxanes at 400°F (205°C) but cause sludging. At that temperature, phenolic antioxidants are ineffective and selenides cause severe copper corrosion. When a sufficiently high degree f nuclear lkylation s ntroduced nto he

structure of the diarylamines, sludge formation can be avoided (Ref. ). Chlorophenylsilicones have been reported to be ade-

quately tabilized t 00°F 260°C) gainst oxidation with iron octoate (Ref. 0). Aromatic compounds containing hree or more ing ystems, or example ,2 - benzanthracene and pyrene, are also effective in retard- ing he oxidation of a chlorophenylsilicone (Ref. 1). Silane fluids have been found to be not usceptible to improvement with oxidation inhibitors Ref. 1).

The presence of trace metals can have a profound effect n he xidative tability of polydimethylsilox- anes and polymethylphenylsiloxanes (Refs. 2, 3). At

392°F 200°C) ead elenium nd ellurium ccelerate oxidation. rganic elenides, romatic mines, nd phenothiazine prolong the ife of silicone ils wo o five imes, but he ife of the ils an e extended o eight times with the use of iron or copper chelates of disalicylalethylenediamine or disalicylalpropylenedia- mine, the solubilized metal acting as an inhibitor. The use of this inhibitor in poorly ventilated systems under oxygen-deficient onditions, owever, eads o he precipitation of the metal as the reduced metal oxide. Cerium complexes have been found not to be subject to this imitation Ref. 4). ew rocesses av e een developed for modifying silicone oils with cerium com-

plexes that raise the stabilization temperature from 617° to 52°F 325° o 00°C) Ref. 5).

5-2.3.4 Ethers

5-2.3.2 Highly Refined Mineral Oils

Natural inhibitors in mineral oils are removed when mineral ils re xhaustively hydrogenated or uper- refined, nd the oils become even more susceptible to oxidative deterioration. On the other hand, the highly refined mineral oils show a better response to additive modification than the less highly purified oils. Satisfac- tory inhibitors at 347°F (175°C) are phenothiazine, phenyl-1-naphthylamine, nd admium diamyldithiocar- bamate (Ref. ).

Tetraphenyltin and bis(p-phenoxyphenyl)diphenyltin perform well as antioxidants for poly(phenyl ethers) t 600°-650°F./j-bis(triphenylstannoxy)benzene, metal salts of N,N-diphertyldithiocarbamic acid, triphenylbismuth, copper xides, etal cetylacetonates, etal ithi- ocarbamates, nd he ickel nd obalt helates of

N-phenyl-5-nitrosalicylimines ere lso ffective n poly(phenyl ether) systems (Refs. 6-18). Tris(pentafluorophenyl)phosphine, tris(pentafluoro-

phenyl)-phosphine oxide, tris(4-heptafluorotolyl)phosphine, nd ris[4-(pentafluorophenoxy)tetrafluoro- phenyljphosphine re ffective n liminating he oxidative deterioration that occurs above 500°F

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(260°C) n luorocarbon polyether iquids but ead o corrosion of ferrous and titanium alloys. Solubility and volatility remain problems in the use of these additives (Refs. 9-21).

5-3 CORROSION NHIBITORS

5-3.1 DEFINITIONS

Corrosion s he eterioration hrough hemical change of a metal nto on e or more of its xides, y- drated xides, arboxylates, luorides, arbonates, r other compounds. The special case of the deterioration of iron or steel by moist air (oxygen) is called rusting. Rusting cannot occur in systems from which oxygen is rigorously excluded. Corrosion of metal components in contact with a hydraulic fluid may occur through he action of water and air present in the system, through

the action of lubricant decomposition products, or by direct chemical action of the fluid on the metal surface. A corrosion inhibitor is an additive that prevents or

decreases orrosive ttack n etals. lthough ts function may e ne of directly protecting he metal surface, an additive may function as a corrosion inhibitor if it nterferes with ny of the processes hat lti- mately ulminate n orrosion. or his eason, he processes of inhibiting corrosion and oxidation are inti- mately elated.

Not only do oxidation products cause corrosion, but corrosion products may promote oxidation. The inter- dependence of oxidation nd corrosion nhibitors an

be llustrated s ollows. An ntioxidant hat etards the auto-oxidation of a fluid will prevent the formation of corrosive acids. Amine antioxidants can eact with and neutralize ertain cidic materials, but romatic amines do not effectively neutralize carboxylic acid, common corrosive oxidation product. In many screening tests for hydraulic fluids and lubricants, oxidation and corrosion are considered concurrently.

5-3.2 MODE OF ACTION OF RU S T INHIBITORS

Rust inhibitors are effective through the formation of closely packed hydrophobic monomolecular layers on the surface of the ferrous metal to be protected (Refs. 22-27). Most organic molecules with an adsorbable po - lar group attached to a hydrophobic chain are effective rust nhibitors. he igher olecular eight olar

compounds re less oluble n ils but av e a greater tendency to adsorb on a metal surface and are, herefore, ore ffective s ust nhibitors. hese losely packed ilms prevent he penetration of water.

Salts r oaps of high molecular weight arboxylic acids-such as naphthenates or sulfonic acids, particularly the petroleum mahogany sulfonic acids-are useful

and nexpensive additives for ubricant ompositions. These soaps, dispersed in nonpolar solvents, form col- loidal ystems. The oaps re dsorbed n he metal surfaces and are in equilibrium with low concentrations of soaps in solution, which, in turn are in equilibrium with he oaps n he olloidal micelle. Although he complex equilibria are no t fully understood, consideration f he ystem s ne n quilibrium llows he explanation of some of the phenomena associated with the se of these ust nhibitors. These ffects nclude temperature range limitations in the use of the inhibitors, mechanical removal and rehealing of coated surfaces, eaching of the inhibitor from solution with wa-

ter, nd depletion of the dsorbed ayers y dilution with hydraulic fluids ot ontaining the inhibitor. The colloid soap micelle also serves as a "sink" for

corrosive cids hat re formed as products of oxidation. Sequestration of corrosive acids by the soap mi- celles ffers n xplanation why he oaps re better inhibitors than the corresponding acids. The combination of the soap micelle with the corrosive acids may occur hrough ooperative icelle ormation r through hydrogen bonding.

5-3.3 LIMITATIONS IN TH E US E OF RU S T INHIBITORS

Since he ost ffective ust nhibitors av e ow solubilities in the base oils, precipitation during storage may occur when inhibitor concentrations exceed 0.5 to 1.0 percent. recipitation ill e ccelerated t ow temperatures ecause nhibitor olubility ecreases with decreasing temperature. Compounded ubricants may uffer significant osses n heir ability o inhibit rusting after six months' storage because of the precipitation f he nhibitor. nhibitor nsolubility s requently vident y he evelopment f aze n the ils.

The arying olubility of an nhibitor n different

base luids esults n orresponding ifferences n n- hibitor effectiveness. For example, he minimum concentration of undecyclic acid required for inhibiting a petroleum luid s 0.20 percent, while 0.75 percent of the same acid is required for di-2-ethylhexyl sebacate, 1.00 percent or olyalkylene lycol, nd .2 0 nd

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both he iquid nd vapor phase with diisopropylam- monium nitrite (Ref. 5).

5-4 VISCOSITY INDEX IMPROVERS

5-4.1 MODE OF ACTION

The addition of certain polymers o a hydraulic oil will increase the viscosity of the oil throughout its use- fu l emperature ange nd mprove ts iscosity-temperature relationship. The contribution of a polymer to the viscosity of a polymer-oil blend s related directly to the effective hydrodynamic volume of the polymer. The hydrodynamic volume of the polymer, n turn, s related to the degree of solvation of the polymer by the base il Ref. 6). igher emperatures avor better solubility of the polymer in the oil hence better solvation nd n expanded" macromolecule. Lower em-

peratures avor contraction of the macromolecule, or stated ifferently, he ormation of a convoluted pe - cies. n his ay , he ffective ontribution f he polymer o he iscosity of the polymer-oil blend s greater at higher temperatures. Not all polymers differ in their contribution to viscosity at different emperatures, but nonetheless they may be referred o as V.l. improvers owing to the inconsistencies of the Dean and Davis iscosity-index ystem (Ref. 7).

The thickening power of a polymer increases as the molecular weight ncreases nd, onsequently, s ts effectivehydrodynamic volume increases. The thickening ower s sually roportional o he olecular

weight o the 0.5 o 0.8 ower (Ref. 8).

5-4.2 LIMITATIONS

In order to maintain a specified viscosity in a hydraulic fluid at a given temperature, a lower viscosity and therefore more volatile base fluid must be compounded with a polymer thickener because the effect of the additive is to increase the viscosity at all temperatures. n applications where low volatility and low viscosity are required, the use of polymer thickeners will be limited.

A econd imitation n he use of V.l. mprovers s their usceptibility o hear. n ydraulic luid- polymer blend, the extended polymer coil may become oriented under high shear stress with a consequent loss in iscosity. ince he original polymer configuration reforms he n he hear orce s emoved, he erm "temporary viscosity loss" ha s been applied to this phenomenon. n lternate erm, orientation iscosity

loss", as een ffered n rder o ifferentiate he effect rom he am e ffect hich ay esult rom "thixotropic viscosity loss" of mineral oils below their cloud point (Ref. 37). Also, under high shear stress the polymer hains may e uptured with onsequent permanent loss in viscosity of polymer-thickened oils. This change, which is not a depolymerization, is more pronounced n lends hat ontain igh olecular weight, or more iscous olymers. ower molecular weight polymers are less susceptible to "permanent viscosity oss".

The term "shear stability", encompasses both effects, temporary nd permanent iscosity oss. aboratory methods for producing accelerated shearing of polymer- thickened ils av e ncluded echanical ump loop n which pump ecycles he luid hrough n orifice, nd onic oscillator est method. ince he latter echnique ffers om e dvantages ver ump loop ests, n ASTM onic Shear Method as een proposed (Ref. 39). In studies of the sonic shear test, it ha s been found that shear breakdown of the polyisobutylenes could be blocked by water contamination, but that he hear tability of polymethacrylates was not significantly ffected nder imilar onditions Ref. 40). he hear tability f olymethacrylates nd polyisobutylenes aries nversely with heir bility o improve the viscosity index (Ref. 41). The ability of an additive to improve the viscosity index decreases with applied shear stress (Ref. 42).

Sources of high nergy other han hear an lso induce egradation f olymer hickeners. hese sources include high temperatures, ultrasonic degradation,

nd

gamma

irradiation

Ref.

3). A final limitation in the use of polymeric materials is their solubility in the base fluid and the compatibility of ompounded luids ith ossible ontaminants. Thus, he olymethacrylates av e n dvantage as . . mprovers n iester luids n hat he additives are not precipitated when the hydraulic fluid is accidentally ontaminated by petroleum oils or the common volatile solvents used to clean hydraulic systems (Ref. ).

5-4.3 EXAMPLES OF EFFECTIVE OLYMERS

The wo lasses of polymeric hickeners hat av e achieved he greatest ommercial mportance re he polyisobutylenes and the polymethacrylate esters (Ref. 30). The effectiveness of each depends both on the nature of the base fluid, nd he particular composition and molecular weight of the polymer. Another class of

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amount that exceeds their solubility to be effective. f the ilicones re present n n mount hat oe s not exceed he olubility, or f the nsoluble particles re greater in size than 100 microns, they promote foaming (Ref. 2). Other defoamers that av e been claimed in the patent literature include the calcium soaps of wool olein, odium lkyl sters of sulfuric cid, potassium

oleate, and esters of sulfonated ricinoleic acid (Ref. 50). Other reportedly useful additives are halogenated compounds, organic ulfates, olyesters, polyhydroxy s- ters, olyhydroxy lcohols, nd ydroxyamines (Ref. 1).

5-5.3 EMULSIFIERS A N D DEMULSIFIERS

Emulsions consist of tw o immiscible or partly miscible liquid hases, dispersed phase of small particles in a continuous phase. Since the lubricating properties of an emulsion will approximate the lubricating properties of the continuous phase, certain water-in-oil emulsions have received attention as fire-resistant hydraulic fluids Ref. 3). These emulsions, which sually ontain about 40 percent water, are stabilized by emulsifying agents that re characterized as molecules having on e group of atoms hat s hydrophilic nd econd group of atoms that is oleophilic. A molecule so constructed s apable of orienting tself at n oil-water interface, decreasing the interfacial tension, and stabil- izing he mulsion. hese dditives, hich may requently be organic acids or soaps, can be selected from known classes of nonionic, anionic, or cationic surface active gents.

More often in hydraulic systems, dditives hat n- duce emulsification re equired. mpurities hat cause foaming can lso cause emulsions if water happens to be present in the system. If the water is emulsi- fied and cannot be readily removed through drainage, lubricated parts can be damaged. Polar impurities can influence the development of either water-in-oil or oil- in-water emulsions.

The election of a uitable demulsifying gent will depend in part on whether an oil-in-water or a water- in-oil emulsion must be counteracted. An additive that

stabilizes n oil-in-water mulsion will enerally e- stroy water-in-oil mulsion, nd ice ersa. hus, most demulsifiers are also surface active agents. om e examples of specific dditives re petroleum ulfonic acids, or salts; dimerized, unsaturated, aliphatic mono- carboxylic acids; nd ulfonated castor oil Ref. ).

5-6

UBRICITY

5-6.1 HYDRODYNAMIC VS BOUNDARY LUBRICATION

Lubricity is a measure of the ability of a lubricant to reduce the friction or

wear between

tw o

solid

surfaces in contact with each other. The lubricant may be called

upon to reduce friction in on e of several ways, depending on the film thickness and the particular conditions under which he ystem s operating. Two mportant variables are temperature and pressure, which in turn will influence the ilm hickness f the lubricant e- tween he two surfaces being ubricated.

When he ilm hickness s greater han bout 5 millionths of an inch, the mode of lubrication is hydrodynamic. Under these conditions, the moving surfaces never come in contact with each other and the friction is largely determined by the viscosity of the lubricating fluid. he nly dditives of importance n hydrodynamic ubrication re polymer additives ecause they increase the viscosity of the fluid.

A s he ressure r emperature etween he u- bricated surfaces is increased, the lubricating film can become ufficiently hin hat etal-to-metal ontact occurs and boundary lubrication develops. Under these conditions the fluid serves as a carrier for boundary or extreme pressure additives and s a oolant.

5-6.2 OILINESS, ANTIWEAR, A N D EXTREME-PRESSURE ADDITIVES

Additives for boundary lubrication are divided into three omewhat ndefinite lasses-oiliness gents, n- tiwear dditives, nd xtreme pressure dditives-the classification being made on the basis of the stringency of the temperature and pressure requirements-temperature eing he more mportant f he ontributing factors. Each of the three classes of additives is effective insofar as it modifies a lubricated surface, reduces the friction, or protects the surface from amage.

5-6.2.1 Oiliness Additives

Oiliness additives, which are usually effective at low temperatures nd ressures, re polar molecules hat can form monomolecular films on a lubricated surface. The most frequently cited example is oleic acid. Oleic acid orms an oriented ilm hat as relatively igh energy of displacement at the interface of the lubricant

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and the metal by adsorption of the acid portion of the molecule on the metal surface.

5-6.2.2 Antiwear Additives

Phosphorus-containing additives are usually classed

as antiwear additives. Under higher pressures and temperatures, these additives are thought to be effective in reducing wear hrough heir ability o orm ron II) phosphate nd ts hydrate n he metal urface Ref. 54). The formation of the iron (II) phosphates has been attributed to the presence of polar impurities, perhaps acidic hydrolysis products, of the phosphate (Refs. 5- 57). The most common example of this type of additive is tricresyl phosphate which is frequently used in con- junction with an iliness agent.

5-6.2.3 Extreme-pressure Additives

Extreme-pressure additives are used under the most severe conditions and are usually sulfurized or chlorinated organic materials. Compounds containing benzy- lic sulfur are particularly effective. Under conditions of extreme pressure or temperature, welding of the wo mating urfaces an ccur with onsequent eizure, galling, or cuffing. n ubricant ontaining n x- treme pressure additive, when high emperatures that can produce welding are approached, the additive presumably undergoes a chemical reaction with the metal surface o orm metal hloride or ulfide ilm hat protects he urface. he ulfur-containing dditives

may be used with lead naphthenate to obtain a protective lead-sulfide coating.

5-6.3 CLASSES OF LUBRICITY ADDITIVES

Lubricity additives function through their action at the urface of the metal o e ubricated; herefore, lubrication f different etal ombinations ay e- quire the use of different additives. A ll base stocks are not qually usceptible o dditive modification, nd the effectiveness of antiwear additives can be modified by he presence of other additives. For these reasons, a very large number of compounds and materials have

been nvestigated s potential boundary ubricants n hydraulic fluids.

5-6.3.1 Additives fo r Mineral Oils an d Esters Ester-based luids and mineral ils re eadily us-

ceptible o dditive odification ith ariety f-

materials. hosphates nd hosphites, articularly tricresyl phosphate, av e eceived considerable attention s dditives Ref. ). Acid phosphates nd ven phosphoric acid show antiwear properties in the proper concentration, but oo arge concentration of phosphoric acid can lead to chemical erosion (Ref. ). Phos- phates and phosphonates containing long alkyl chains

provide oo d ubricity nd, n ddition, unction s antioxidants Ref. 8). he ffectiveness of ricresyl phosphate s educed n he presence of polar om - pounds uch s petroleum ulfonates, hich have greater ffinity or metal urfaces than oes ricresyl phosphate (Ref. ). Metal dithiocarbamates function as antiwear dditives n ster luids, but not n mineral oils. Fluorinated esters have been found to beas susceptible o ntiwear dditives s onfluorinated sters (Ref. 9), but many additives are not sufficiently soluble to be used in he fluorinated esters.

5-6.3.2 Additives fo r Silicon-containing Fluids

A great many additives that are effective in mineral oil and ester fluids are ineffective in silicones, silicates, and siloxanes. ilicones show especially poor additive susceptibility or ubricating teel-on-steel. The wear properties can be improved in ester-silicone blends, but such a high proportion of ester is required that the good high-temperature properties of he ilicones re ost (Ref. ).

Silicon-containing liquids are usually not susceptible to modification y ntiwear dditives. here s vidence hat he ilicon eacts referentially ith he metal to be lubricated, forming a coating on the metal that s o onger eactive with he ntiwear additive. Silicones and silicates themselves can be used as additives in esters and mineral oils to obtain antiwear properties, fact which uggests hat oft, nert ilicon- iron alloy is formed (Ref. ). Some attempts have been made to modify the chemical structures of silicones to improve heir ear roperties. riction nd ear studies f chlorinated methylphenyl silicones show an improvement ver onhalogenated methylphenylsili- cones, but high friction and wear are still observed with hard steel on soft steel and soft steel on soft steel (Ref. 60). n addition, the chlorine-modified silicones suffer a second limitation in being poorer lubricants for steel on opper above 400°F han re unmodified ilicones (Ref. 60). A great improvement in the lubricity of chlorinated phenylmethylsilicone was found when the liquid as ooked ith in etrachloride Ref. 0). Fluorosilicone luids re eported o av e t east

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equivalent ear erformance n he hell -Ball Extreme ressure ester o i-2-ethylhexyl sebacate (Ref. 61).

A final class of silicon-containing fluids, the tetraalk- ylsilanes, have better dditive usceptibility han he silicones, silicates, or siloxanes. Although tetraalkylsi- lane base luids xceed arget wear imits, heir wear

properties can be improved with phosphates, phosphites, phosphonates, phosphorothioates, and sulfonated petroleum derivatives Ref. 2).

5-6.3.3 Additives for Aryl Ether Fluids

A variety of additives av e proved ffective n m- parting mproved ear roperties o oly(phenyl ethers) (Ref. 6). These additives include bis(cyclopen- tadienyl)titanium bis(trichloroacetate) and its polysulfide derivative, diphenyltin bis(trichloroacetate), is(- triphenylphosphine) nickel dichloride, and particularly, trichloroacetic cid. Tricresyl phosphate t the 5 percent level is also effectivein aryl ethers (Ref. 63).

a hydraulic fluid in order to more effectively eal he system. ertain luids, owever, notably he ilicates and iloxanes, re poor ubber solvents but oo d olvents fo r rubber plasticizer. The result is that the plasticizer can be extracted from the rubber with consequent shrinking nd hardening.

The approach to solving this problem is the addition

of 5 to 5 percent of compounds to the fluids that can ac t as rubber plasticizers (Refs. 9, 46, 67). Esters such as butyl leate, i-2-ethylhexyl ebacate, nd dibutyl phthalate, and certain aromatic compounds have been most ommonly se d n his pplication. With uch large quantities, he function of the added material s not so much an additive as a modification of the base liquid through blending. In so modifying a liquid, special attention must be given to hanges n he hysical properties.

5 -9 HYDROLYTIC INHIBITORS

5-7 POUR POINT DEPRESSANTS

An oil that does no t readily crystallize may be cooled to emperature t which he iscosity ecomes o great that it will not flow under the conditions of the pour point est. This iscosity or glassy pour point s inherent n he chemical nature of the oil nd can e modified only hrough the blending of oils or mixing the oils with ight diluents.

Petroleum ils hat ontain mall percentage of wax may cease to flow at a much higher temperature owing to he formation of a network of wax rystals. Such a "waxy" pour point may be lowered through the use of additives. A number of explanations have been offered or he mode of action of these dditives, but their effect is thought to depend on the additive's ability to modify the crystallization process so that more and smaller crystals with higher volume-to-surface rea ratio are obtained. The modified crystals do not orm networks so easily Refs. 4-65).

Materials that are used as commercial additives include he olyalkylnaphthalenes, olymethacrylates, and alkylated polystyrenes. Other polymeric additives are also effective (Ref. 6).

5 8 SEAL DEGRADATION

RETARDANTS

It s desirable hat lastomeric eals well o om e extent (about 5 percent) when they are in contact with

Silicate sters ndergo ydrolytic egradation o produce products that are both corrosive and insoluble; carbocylate and phosphate esters seldom yield insoluble products n ydrolysis. hief interest n inding additives that will correct these undesirable properties has een n onnection ith ilicate nd isiloxane based luids, lthough phosphates, phosphonates, nd carbocylates av e eceived om e ttention. roperly inhibited, ilicate fluids av e een hown o av e c- ceptable hydrolytic stabilities (Ref. 67). n designing a hydraulic luid, t s ften preferable o modify he

chemical structure to obtain hydrolytic stability rather than o se inhibitors. Without nhibitors, any ilicates arnish opper

and deposit some silica under conditions of hydrolysis at 00T, ut dditives uch s etal henates, phenyl a - naphthylamine Refs. 5, 8), N, '- dibutyl - p- phenylenediamine Ref. ), nd /^dioctyldiphenylamine Ref. 6) re ffective t concentration of 0.1 ercent n tabilizing he luid. Since he romatic mines re ffective nhibitors n concentrations less than those required for their use as antioxidants, he dditive an erve dual urpose. Diphenylamine nd phenothiazine re ess ffective,

an d phenolic nhibitors are ineffective (Ref. 8) . The nhibitors ose heir ffectiveness fter om - pounded hydraulic fluid is exposed to the rubber swell test, presumably as a result of the leaching of the plasticizer rom he ubber (Ref. ). The additives re not effective in 400°F hydrolytic stability tests (Ref. 6) .

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5-10 CAVITATION NHIBITORS

Cavitation s oorly nderstood henomenon. There are few data available in the literature on the use of additives to change the cavitation resistance of hy - draulic fluids. The usual procedure to avoid damage to structural parts ofthe hydraulic system from cavitation

in the hydraulic fluid is to use materials that are resistant. Softer metals are plastically deformed; hard brittle metals are pitted. Hard, ough metals, uch s cobalt chromium lloys, re ery esistant o amage (Ref. 69).

There has been om e development work, owever, on cavitation inhibiting additives. Studies in the literature suggest that if the cavities consist of a vacuum or the vapor of the iquid, hey will ollapse with more energy elease han f they ontain om e oreign as, such as air (Ref. 9). The work that has been done on cavitation inhibitors ha s been directed toward "filling" the cavities with foreign gas".

O ne of the most uccessful avitation nhibitors s water. lthough eports re ontradictory s o he performance of water, it was used in on e study at a ratio of 1:200 in a hydraulic fluid to reduce cavitation erosion in control valves (Ref. 70). The hydraulic fluid was a commercial phosphate ester liquid. Results indicated almost complete elimination of the cavitation damage that had been occurring with the "unwatered" hydraulic luid. heoretical work n he se of water n phosphate ester indicated that 0.5 percent water would increase the vapor pressure and reduce the cavity collapse pressure (Ref. 9).

Several reports summarized n Ref. 9 av e shown that some additives, as well as some contaminants, increase the actual damage from cavitation. The consen- sus expressed in the literature is that every property of a liquid has a two-fold and opposing effect on cavitation and the resultant damage. The various effects are often interacting and complex. The limited data available uggest hat many of the andidate dditives or cavitation nhibition may educe he otal mount of cavitation resent ut ncrease he esulting avitation amage.

5-11 BIOCIDES

Biocides are additives designed to inhibit the growth of micro-organisms in iquids. The Air Force, Army, and any etroleum ompanies have ponsored e- search concerning microbial attack and growth in pe - troleum products used as fuels (Refs. 71 , 72). However, there ha s been almost no work on micro-organisms in

hydraulic fluids. n eneral, hydraulic fluid specifications contain no requirements on inhibiting microbial growth. But microbial deterioration of hydraulic fluids can be a real problem and should be considered in the selection of a suitable liquid. n some instances, it will be ecessary o dd n nhibitor or iocide o prevent growth.

For a biocide to be successful and desirable, it must: (a) have low toxicity to the skin or upon inhalation, (b) be soluble in hydraulic fluids and their additives, (c) be noncorrosive o metals, d) e conomically uitable (inexpensive or ffective n ery ow oncentration), and (e) have no degrading effect on other properties of the liquid such as viscosity, stability, fire resistance, etc. Although there are numerous effective inhibitors available, none satisfy all of the above requirements. Many potential inhibitors are toxic to humans and many that are ffective re oo xpensive or equire uch arge concentrations hat hey hange he roperties f the iquid.

Because many liquids used as hydraulic fluids and al l jet fuels are hydrocarbons, the biocide research results for jet fuels are, in general, applicable to hydrocarbon hydraulic luids. thylene lycol onomethyl ther (EGME) and glycerol is a water soluble additive that is effective as a biocide in jet fuel. It ha s been reported that s ittle s .05 percent y volume eeps micro- organism growth to a minimum (Ref. 73). Quaternary ammonium cetate, thylidene iacetate, nd tri-«-butyl borate are other inhibitors recommended for use in jet fuel in bulk storage tanks (Ref. 4) . n some instances, other additives such as antioxidants or anti- icing compounds have been found to have a secondary

effect s biocides (Ref. 5).

REFERENCES 1 . . R. Fenske t l. , Fluids, Lubricants, Fuels

and elated aterials, ADC-TR-55-30, Parts hrough VIII.

2. . avner, . R. uss, nd C. O. Timmons, "Antioxidant ction f etals nd etal- Organic Salts in Fluoroesters and Polyphenyls Ethers", . Chem. Eng. Data 8, 91 1963).

3. . G. Kanpp and H . D . Orloff, "Improved Lu- bricating O il Antioxidants", nd. Eng. Chem.

53 , 5 1961). 4. . C. Atkins et al., "Synthetic Lubricant Fluids From Branched-Chain Diesters - Part II", Ind. Eng. Chem. 9, 84 (1947).

5. ohen, Murphy, O'Rear, Ravner, and Zisman, "Esters as Tailor-Made Lubricants", nd. Eng. Chem. 5, 766 (1953).

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6. ueltgen, ugasch, nd osgrove, Or- ganosilenium ompounds s igh-Tempera- ture Antioxidants", Lubrication Engr. 8, 18 (1962).

7. . W . Adams, Additive Studies n Research on igh-Temperature as-Turbine ubricants", Sei. Lubrication (London) 12, No. 8, 6

(1960). 8. laus, Tewksbury, nd enske, Preparation, Properties, nd om e Applications f uper- Refined ineral ils", SLE rans. , 15 (1962).

9. . W . Furby t l. , he Development of High Temperature

ircraft ydraulic luids, WADC-TR-54-191 1954).

10. rown, Holdslock, and McGuire, Silicone Fluid Research for th e Development of High-Tempera- ture Hydraulic Fluids and Engine Oils, WADC- TR-56-25, Parts , I, nd II 1956).

11 . . M . ilverstein, Synthesis and Evaluation of

High-Temperature ntioxidants or ynthetic Hydraulic Fluids and Lubricants, WADC-TR- 58-335, Parts nd I 1958).

12 . urphy, aunders, nd Smith, Thermal nd Oxidation tability f Polymethylphenylsilox- anes", nd. Eng. Chem. 2, 462 1950).

13 . tkins, Murphy, nd Saunders, Polymethyl- siloxanes-Thermal nd xidation tabilities", Ind. Eng. Chem. 9, 395 1947).

14 . . R. Baker and C. R. ingleterry, Stabiliza- tion of Silicon Lubricating Fluids above 200°C by ron, opper, erium, nd ther etal Compounds", . ng . hem. ata , 46 (1961).

15 . aker, Kagarise, O'Rear, nd niegoski, Sta- bilization of Silicone Lubricating Fluids at 300° to 400°C y oluble Cerium omplexes " , . Chem. Eng. Data 1, 10 (1965).

16. rown t l. , esearch nd Development n High-Temperature Additives for Lubricants and Hydraulic luids, ADC-TR-59-191, arts I-IV 1959).

17. mith et al., Research on High-Temperature Ad- ditives for Lubricants, Office Tech. Serv. Report AD281, U . . Dept. Com., 31 1962).

18.

. R. temniski et al., Antioxidants for High- Temperature Lubricants", ASLE Trans. , 3 (1964).

19 . . E. Dolle and F. J. Harsacky, New High Tem- perature Additive Systems for PR-143 Fluids, AFML-TR-65-349, January 966.

20. . E. Dolle, High emperature Corrosion Pre- ventive dditives or luorocarbon olyether Fluids, AFML-TR-67-210 (1967).

21. . . damczak, . . enzing, nd . Schwenker, Proceedings of the AFML Hydraulic Fluids Conference, AFML-TR-67-369, Decem- be r 967.

22. . R. Baker nd W. A. Zisman, Polar-Type Rust nhibitor art ", nd. ng . hem. 40 , 338 1948).

23. aker, ones, nd Zisman, Polar-Type Rust Inhibitors - Part I", nd. Eng. Chem. 1, 37 (1949).

24. . R. Baker nd W. A. Zisman, Liquid nd Vapor Corrosion Inhibitors", Lub. Eng. , 17 (1951).

25. . R. Singleterry and E. M. Solomon, "Neutral and asic ulfonates", nd. ng . hem. 6, 1035 1954).

26. . aufman nd . . ingleterry, Micelle Formation y ulfonates n onpolar olvent", J. Colloid Chem. 0, 39 1955).

27. . D. Bascom, S. Kaufman, and C. R. ingleterry, Colloid Aspects of th e Performance of Oil- Soluble oaps s ubricant dditives, 959, Fifth World Petroleum Congress, ection VI, Paper 8, New York 1959).

28. isser, essina, nd nead, Hydroxyaryl- stearic Acids as Oxidation and Rust Inhibitors in ubricants", nd. ng. hem. 8, 00 1 (1956).

29. nead, Messina, and Gisser, "Structural Effects of Arylstearic Acids as Combination Oxidation and Rust nhibitors", nd. Eng. Chem., Prod.

Res. Dev. , 22 1966). 30. . atton, ntroduction o Hydraulic Fluids,

Reinhold Publishing Corp., N.Y., 962. 31 . . Messina and A. Mertwoy, "Inorganic Salts in

Mahogony ulfates nd heir ffect n e- troleum Hydraulic Fluids", ub . ng. 3, 6 (1967).

32 . . Wyllie nd A. W. Morgan, Prevention of Corrosion n lycerol-Water ydraulic Fluids", . ppl. hem. London) 5, 89 (1965); C. A. 3, 552 (1965).

33 . . B. Jordan, Study of Corrosion Inhibitors and Antioxidants for Alcohols Found n Hydraulic

Brake Fluids, Ordnance Project TB5-5010F, D . A. roject o. 93-21-054, ngineering Laboratories Report No. 28, Aberdeen Proving Ground, Maryland (1955).

34 . . . Baker, Volatile Rust nhibitors", nd. Eng. Chem. 6, 592 1954).

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Pour Phenomena Exhibited by Solution of Bi- nary «-paraffin mixtures; Part II, Mechanism of Pour Depression; Part III. Effect of W ax Com- position n Response to Pour Depressant nd Further evelopment f he echanism f Pour Depression", J. Inst. of Petroleum 51 , 228, 235, nd 43 1965).

66 . . E. Lorensen and W . A. Hewett, "Pour Point Depression I; tructure s. ctivity", m. Chem. Soc, Div. of Petroleum Chem. Preprints 7, B-71, 962.

67. . LeMar, Development of a Wide-Temperature Range Hydraulic Fluid, RIA Report No. 7- 2254 , ock sland rsenal, ock sland, l- linois (1967).

68. . W . Furby, Development of Non-Flammable Aircraft Hydraulic Fluids, AF-TR-6685 ATI- 188471).

69 . . Godfrey nd N. W . Furby, Cavitation of Oils and Hydraulic Fluids", n: R. . Adamc-

zak, R. J. Benzing, and H . Schwenker, Proceed- ings of th e AFML Hydraulic Fluids Conference, AFML-TR-67-369, December 967.

70 . . Hampton, "The Problem of Cavitation Ero- sion n Aircraft Hydraulic Systems", Aircraft Engineering 38, 1966).

71 . . harpley, lementary etroleum icrobi- ology, ulf ublishing ompany, ouston, 1966.

72 . . Davis, Petroleum Microbiology, Elsevier Pub- lishing Company, N.Y., 967.

73 . . O. Hetzman, "The Control of Bacterial and Fungal Growth n et Fuels y U se of a Fuel Additive", evelopments n ndustrial i- crobiology , 05 1964).

74 . . U . Churchill and W . W . Leathern, Develop- ment of Microbiological Sludge Inhibitors, ASD- TR-61-193, st Reprint, September 962.

75 . . . lanchard nd . . oucher, echanism of Microbiological Contamination of Jet

Fuel and Development of Techniques for Detec- tion f Microbiological ontamination, PL- TDR-64-70, Part I, February 966.

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CHAPTER

STORAGE A N D HANDLING

6-1 ONTAINERS

6-1.1 GENERAL

The function of hydraulic fluid containers is simply to contain the fluid during transport and storage. The container must e trong nd ight nough o ssure protection f ts ontents, nd t ust reserve he original cleanliness of the fluid. Characteristics important o he esign nd election of containers or specific hydraulic fluid include the container materials, dimensions, nd storage conditions o which the container will be subjected. Also of importance are standards for proper labeling, and guidelines for the purchas- ing and ordering of containers.

Interior coatings or liners are common for hydraulic fluid ontainers made or ommercial se , specially the 5-gal rums. or ilitary pecification luids, however, nterior coatings or iners enerally are not required. When nterior oatings or iners re sed, they must be of a material that will no t react with the hydraulic luid.

6-1.3 CONTAINER SIZES, STORAGE, A N D MA RK IN G

MIL-STD-290C (Ref. ) includes detailed information regarding required methods of packaging, packing, and marking of hydraulic luid ontainers. Table -1 and Figs. 6-1, 6-2, and 6- 3 list and illustrate applicable data regarding size.

6-1.2 CONTAINER MATERIALS

Industrial nd military equirements or materials for ydraulic luids ontainers ary, ut he sual materials re teel or luminum. n eneral, military hydraulic fluid specifications fo r containers for on e gallon or less require that they be packaged in metal cans, 28 gage or lighter, conforming to Federal Specification PPP-C-96A Ref. ). eavier ag e teel s se d or containers of - nd 5-gal apacities. or nstance, 55-gal drums must comply with Federal Specification PPP-D-729B Ref. ) nd ange rom 2 o 8 age; 5-gal ontainers must comply with Federal pecification PPP-P-704B (Ref. 3) and range from 24 to 26 gage.

Exterior coatings for military purposes usually con- form o Federal pecification TT-E-515 Ref. ) or quick-drying enamel. Containers of on e gallon or less are enerally painted ed, while arger containers re painted olivedrab. Exterior coatings for commercial use depend on he manufacturer's preference and frequently ncorporate a color code o distinguish the contents. Fig. 6-1 . One-ga l Screw C ap Can, Ty p e V, Class 4

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TABLE 6-1.

H Y D R A U LI C FLUID C O N TA I N ER SIZES5

Container Container Capacity Type Class Ca p Design Shape

Can 1-pint V 4 ,8 Screw cap, spout, or special closure Oblong

Can 1-quart V 4 ,8 Screw cap, spout, or special closure Oblong

Can 1-quart I - Hermetically sealed Cylindrical

Can 1-gallon V 4 ,8 Screw cap, spout, or special closure Oblong

Can 1-gallon I - Hermetically sealed Cylindrical

Pa ü 5-gallon - - Screw cap, spout, or special closure Cylindrical

Drum 55-gallon - - Bung Cylindrical

Fig. 6-2. One-qt Hermetically Sealed Can , Ty pe

Storage requirements are frequently included in hy - draulic luid pecifications. or xample, IL-H- 5606B hydraulic fluid specification states that "prior to use n he ntended quipment, he product ay e stored nder onditions f heltered r nsheltered storage n eographic reas anging n emperature from-57° o 49°C -70° o 120°F)" Ref. ). Hy- draulic fluid specifications often include storage stability equirements which a liquid must pass to become qualified under the specification. For example, in M I L - H-8448B Ref. ), andidate iquid must as s he following storage test: Three 4-oz samples of the test fluid shall be placed in separate airtight glass containers and tored n he dark t emperatures etween 5°F (18°C) and 90°F (32°C) fo r a period of 12 months. No

agitation of the samples shall be permitted during stor- ag e of the samples. The samples shall then be examined

visually o ssure hat hey xhibit o ormation of resinous gums, sludges, or insoluble materials or separation."

Marking nstructions equired n ydraulic luid containers for military use are given in MIL-STD-290C (Ref. ). References given in MIL-STD-290C (Ref. ) specify the colors and types of inks (Ref. ), acquers (Ref. 9), and enamels (Ref. 0) to be used for marking containers. The information normally required on large containers, nd ts roper ocation, s llustrated n

Fig. 6 -3 . ne-pt Spou t T op Can , Type V, Class 8

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Figs. 6-4 and 6-5. The numbers in parentheses on Fig. 6-5 refer to the letter size to be used. The abbreviations listed n Table -2 re requently se d or hydraulic fluid ontainer marking.

TABLE 6-2.

EC O M M EN D ED ABBREVIATIONS5

a. uantitative Units Dozen Z Each

A

Gross

R

Hundred

D

Thousand X Weight

T

Cube (cubic foot) U Gallon A Quart

T

Pint Ounce Z Cubic Centimeter C b. Procurement Marking Abbreviations

Aircraft FT Automotive UTO Engine

NG

Lubricating

BE

Petroleum ETRO Preservative RESERV Temperature

M P

Turbine RB Reciprocating ECIP Gyroscope

Y RO

Caution, arning, nd nstruction arkings re sometimes required on containers. For example, MIL- H-27601A containers must include the following markings Ref. 1): "INSTRUCTIONS: Destroy ll markings n his ontainer when mpty. Do not mix with any fluid except those of MIL-H-27601 and revisions."

6-2.1 SOURCES OF CONTAMINATION

There are many sources of hydraulic fluid contamination. om e of the more ommon re : 1) in t nd dust, 2) moisture, nd 3) dditive roblems.

6-2.1.1 Contamination from in t an d Dust

Lint, dust, nd other oreign matter hould e he least common type of fluid contaminant. Their source can sually e raced o arelessness n he part of personnel who handle the fluid. Airborne dust can en - ter the container when it is left uncapped or improperly sealed. Lint and other foreign matter can be traced to careless procedures n wiping ids, unnels, nd other items which om e into contact with he fluid.

6-2.1.2 Moisture Contamination During

Storage

Moisture is one of the greatest enemies of hydraulic fluids and systems, xcept for aqueous yp e hydraulic fluids and the systems designed to use them. In general, special care should be taken to make containers waterproof-especially when they are stored without protection rom he weather. ntroduction of moisture nto waterproof containers y breathing" nd ondensa- tion is a problem whenever containers are exposed to frequently nd widely arying emperatures. For his reason, torage onditions where uch problems an occur hould e voided. ontainers tored ut-of-

doors should be stored on heir sides to prevent water from tanding n ontainer ops. ontainer ids nd bungs hould be periodically hecked or tightness.

6-2.1.3 Contamination Accompanying Additives

6-2 CONTAMINANTS

Fluids se d n ydraulic ystems must eet igh standards of purity. Malfunctions in hydraulic systems

frequently can be traced directly to contaminated y- draulic luids. lthough ontamination an ften e attributed o ources ot elated o he handling nd storage of the hydraulic fluid such s contamination particles due to system wear), many problems can be eliminated by proper handling and storing of hydrau - lie luids.

Impurities accompanying additives are, in the strictest sense, a manufacturing problem but on e which may ultimately become the headache of the hydraulic fluid handler. or xample, t as een eported hat n additive in some MIL-H-5606B fluids has, on occasion,

been ound o ontain ontaminant oluble n he additive tself but nsoluble n he inished hydraulic fluid (Ref. 2). Some additives for hydraulic fluids can cause onsiderable ontamination roblems he n moisture accumulates in the hydraulic fluid. Hydraulic fluids with orrosion nhibitors re prone o orm slime with moisture contamination Ref. 2).

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0) 4>

SPA CE ALLOWANCE OR CLOSURES

Military Symbol, Nomenclature, Grade, Type, Class

Contractor's Name

DOMESTIC ADDRESS

CAUTION A N D USE MA RK IN G S

( A ) op Markings ( B ) id e Markings

Fig. -4 . Markings on T op an d Side of 55- ga l Drum

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One larification oncerning ater nd ydraulic fluids must be made, however. n certain fire-resistant hydraulic fluids, water is a welcome ingredient, making up from 20-70 percent of the liquid. Such fire-resistant hydraulic luids re ormed y n mulsion of water dispersed in a second liquid, such as oil or a glycol. n these liquids the distinction between water as a needed

ingredient and water as a contaminant s clear. A istinction ust e ade etween il-in-water emulsions and water-in-oil emulsions. Although a stable olution an e made y dispersing il n water, problems ith orrosion nd ear re ore pt o occur with this type of emulsion. "Inverse" or water-in- oil emulsions, on the other hand, offer the fire-resistant quality of water while etaining he ubricating nd anticorrosion qualities of the il. n inverse" mulsions, water is the dispersed phase while oil is the continuous phase. n oil-in-water emulsions, he situation is reversed-the oil is the dispersed phase and the water is the continuous hase.

6-2.2.2 Solid Contaminant Particles

Of al l contaminants, solid particles are of most re- quent oncern. heir measurement s sually etermined according to size and number. The cleanliness of a hydraulic luid s normally eported s he elative "solid particle cleanliness".

Solid particle contaminants are either of the fibrous or nonfibrous ariety. ibrous particles av e arge length-to-diameter atio. A ibrous particle as een defined by Aircraft Industries Association as on e hav-

ing ength-to-diameter

atio

greater

han

0

o . Nonfibrous solid particle contaminants include all par-

ticles ot n he ibrous lass. Their rregular hapes make t ecessary o efine heir ize y heir arg- est dimension.

The unit of measurement for solid particle contamination is the micron (about 9 millionths of an inch). The normal human ey e can detect particles as small as 40 microns. However, contaminant particles as small as 1/2 micron may be of concern.

Because of the wide variety of hydraulic fluids and their qually ide ariety f pplications, here re many standards of fluid cleanliness. MIL-H-5606B re - quires that (1 ) there be no particles over 00 microns in ize, nd 2 ) he otal ontamination n 00-ml sample retained on a 0.45-micron cellulose filter be no more than .3 mg.

Table -3 presents data n generalized contamination limits fo r hydraulic fluids as proposed by the Air- craft ndustries Association Ref. 5). t s ot o e

considered s tandard or ll hydraulic luids. n- deed, f contamination evels are to be established or a hydraulic luid, t s est o efer o he manufacturer's data fo r the most reliable indication of the contamination imits and to take into account the design of the system(s) in which the liquid will e sed.

Table 6- 4 is an example of contamination limits for

hydraulic luids stablished y ne ircraft ompany (Ref. 5). Not only is the maximum number of particles specified, but the maximum weight of the contaminant per 100 ml of liquid is also specified. The differences in contamination limits between Tables 6-3 and 6- 4 serve to llustrate he elative nature of fluid cleanliness". What may be a "clean" fluid in on e application may not be "clean" enough for another. The specific application of the fluid is always the ultimate factor in determining contamination imits.

6-2.2.3 Liquid Contaminants Other Than Water

In ddition o olid particle nd water ontamination, ontamination rom other iquids, both miscible and mmiscible, an ccur.

Liquid contaminants in hydraulic fluids often enter a ystem s esult of mixing accidental r nten- tional) two or more hydraulic fluids. Accidental mixing often occurs when eplacing he hydraulic luid n system ith nother ydraulic luid ithout thorough cleaning of the system. Liquid contamination of a hydraulic fluid an lso occur when ransferring the iquid nto nclean ontainers. n eneral, uch transfers hould e avoided. n om e ases, owever, Military pecifications indicate that wo different iquids are compatible and may be mixed. Such a mixture may be considered usable in that it does not form resinous gums, ludges, or insoluble solid materials; ow - ever, the liquids in the mixture are contaminated in the sense that the liquids may no longer retain their original characteristics. Such characteristics may be critical in ertain pplications that equire a clean" luid.

Contamination of a hydraulic luid y ils or olvents used in or on the hydraulic system is a frequent form f ontamination. his yp e f contamination reduces he ffectiveness f he ydraulic luid y changing characteristics such as viscosity, density, and lubricating ability or by attacking system components such as seals. However, the oil or solvent may have no chemical ffect n he hydraulic luid tself, particularly in the case of petroleum base hydraulic fluids and petroleum raction ils or solvents Ref. 2).

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contamination an occur n hydraulic luids. f sufficient quantities of the organisms are allowed o grow unchecked, they can clog filters, restrict small orifices, and ause poor operation of close tolerance parts.

The growth of micro-organisms can be increased by the presence of other ontaminants n he hydraulic fluid. Water contamination, or example, provides n environment, and is necessary, fo r the growth of living organisms. In most cases, elimination of microbial contaminants with biocides does no t solve the underlying contaminant roblems hat originally ontributed o growth of the micro-organisms (Ref. 6).

6-2.3 EFFECTS OF CONTAMINATION

Contamination in a hydraulic system is damaging to the hydraulic fluid and to the system in which it is used. The egree of contamination sually egins t ow level nd ncreases ecause of the ormation of contaminants in the system itself (especially solid particle contaminants aused y ystem ear, xidation,

and orrosion).

Solid particles n he order of 00 microns an e formed rom maller nes. This ffect has been specially noted in noncorrosion-preventing petroleum base hydraulic fluids (Ref. 2). These fluids are highly dielectric and contaminant particles retain a static charge. The esult s hat when he luid s xposed o on g periods of agitation, such as in shipping, the probability of particles olliding with ne nother ncreases nd particle agglomerations form. Fluids with submicronic particles have been known to form 5- to 200-micron particles under these conditions (Ref. 2).

Moisture s a contaminant which auses a slime in some hydraulic luids. The ecessary ngredients or the ormation f his lime hat an log ilters re tricresyl phosphate (an antiwear additive used in several hydraulic fluids), an alkali, an d moisture (Ref. 2).

In a hydraulic fluid of the corrosion-preventive type, moisture can also cause the formation of a slime resem- bling gg white. When ufficient moisture s present, the orrosion-preventing dditives an xhaust hem-

selves by wrapping

up"

the

moisture

in additive and

water dispersions Ref. 2).

6-2.3.1 Effects of Contamination on th e Hydraulic Fluid

Once a hydraulic fluid becomes contaminated, t s usually no longer suitable for use. The destructive effects of contamination are often of a "chain-reaction" nature and produce further damage to the liquid. While this is not always the case, it is easier to prevent damage by avoiding contamination through proper handling and storage techniques than t is o make repairs that ay

be equired s esult of using contaminated liquid. There are a number of situations where contamina-

tion can grow even within a closed and sealed system. One example of the "chain reaction" that ca n occur is the effect of moisture n hydraulic luids without n- ticorrosion dditives. orrosion articles esulting from moisture, n ffect, ct s wear particles which expose clean metal surfaces that subsequently succumb to corrosion Ref. 2).

It has been observed that the presence of solid particle contaminants can affect the oxidation resistance of hydraulic fluids. Although most hydraulic fluids ontain oxidation nhibitors, heir ntended ffect an e

seriously depleted when olid particles accelerate oxidation of the fluid and "use up" the inhibitor (Ref. 2). When xcessive ontamination hus wears out" he oxidation inhibitor, the hydraulic fluid can easily succumb to the effects of oxidation and, consequently, the formation of corrosion products.

6-2.3.2 Effects of Contamination on th e Hydraulic System

System damage or failure may be caused in a number of ways. Solid particle contaminants may result in friction an d wear, jamming, or seizing. In hydraulic mechanisms where close-fitting parts move at relatively high speeds, olid particle ontaminants hear the aces of system omponents. The buildup of more nd more wear particles an , herefore, esult rom n nitially

small mount f olid article ontamination. ince moisture may also produce solid particle contaminants due to corrosion, ts ultimate effect can e the same- more and more contaminant buildup. Plugging of small openings and filters may result from solid particle contamination or from the formation of slimes.

Hydraulic system fouling can also be caused by the chemicai .nteraction of hydraulic fluids with seals. It is a design error to use seals or other system components that ould e eactive with he luid. he esult s formation of gels, ludge, nd brasive particles hat can urther damage a hydraulic system.

A convincing illustration of the ill effects of hydrau-

lic fluid contamination is to compare system life under controlled contamination levels with system life under the best contamination free conditions allowed by present technology. O ne report examines the effect of vari- ou s ontrolled olid particle ontamination evels n servo-valve internal eakage. O ne conclusion eached,

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which is indicative ofthe effects of at least solid particle contaminants, s hat ormal ontamination an e controlled to the point where the life of a servo-valve assembly can be increased by as much as 277 percent (Ref. 7). Table 6-5 presents data on some of the many types of contaminants and their general effects on he most common components in a hydraulic system. (Ref. 8).

6-2.4 METHODS OF DETERMINING CONTAMINATION

The equired leanliness of hydraulic ystem s relative and is dependent on the design of a particular system. Although the criteria for cleanliness may vary for ifferent ystems, he ethods f ontaminant measurement are basically alike. Methods of solid particle contaminant measurement nvolve counting, izing, and/or weighing of the particles in a given volumeof fluid. Methods of determining the amount of liquid contaminants present n hydraulic luids sually n- volve hemical r hysical rocedures-distillation, separation with a solvent, or isolation of the contaminant by chemical eaction.

6-2.4.1 Solid Particle Contamination Measurement by Counting

(1 ) Microscope Methods: Three test procedures for determining the solid parti-

cle contamination in hydraulic luids by counting are

in eneral se . They re : Federal Test Method 00 9 (Ref. 9), ASTM -2390-65T Ref. 0) , ndAero- nautical ecommended ractice ARP-598 Ref. 21). The hree ethods re ery imilar n he rocedure nd he eporting of results. n ach method sample f he pecimen s iltered hrough .45- micron ellulose membrane filter. The ilter s xamined under a microscope and the number of solid particles in a given area of the filter is counted. The particle counts re grouped n he ollowing ize anges in microns): o 5, 5 o 25, 5 o 0, 0 to 00 , ver 100 (length-width ratio under 0:1), over 00 (length- width atio ver 0:1). The otal number of particles present is calculated by statistical methods.

(2 ) Automatic Counting Methods: The edious ature f most article-contaminant

counting nd eighing ethods an e voided through he se of automatic particle ounters. Two types f utomatic ounters xist. ample ounters measure the number of particles in a sample of hydraulic fluid. On-stream counters record the number of contaminant particles in a system while it is in operation.

(a) ample-type Automatic Counters: O ne ample-type ounter* s apable of counting

solid particle ontaminants nd ndicating heir ize. Electrodes n ach ide of a mall hannel detect change in resistance whenever a contaminated sample of hydraulic luid asses. he luid ample must e

Made by Coulter Electronics, nc., Chicago.

TABLE 6-5 . EFFECTS O F VA R I O U S CONTAMINANTS ON HYDRAULIC SYSTEM CO M PO N E N T S18

Scale Rubber Metal Airborne

Dust Sand Lapping Compound

Process Residues Fibers

OÜ X X X X Reservoir X X X XX X X Pump X XXX X X X

Relief Valve X XX X X X X Control Valves X X X X X Actuators X X X X

Accumulators X X X X X X Pipe Fittings,

Hoses, Etc. X X X XX X X Filter X X X XX X

X-Noticeable XX-Medium XXX-Strong

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AMCP 706-123

made onductive efore esting y ixing t with suitable solvent. Passing contaminants cause a voltage pulse in proportion to the size of the particle so that the number of particles within a certain size range can be determined. Measurement may be made down to about 5 microns.

Another sample-type counter* works on an lectro- optical system capable of measuring and counting contaminant particles on test slides. Measurement may be made down to 1.0 micron. Also operating as an electro- optical device is a sample-type counter* which llows a sample of the fluid on a slide to oscillate past a photo- cell which counts and sizes the contaminant particles.

(b) n-stream Automatic Counters: A second category of particle counters provides for

automatic sampling of the hydraulic fluid. On-stream counters connect directly nto an operating hydraulic system and tap fluid from a point in the flow believed to ield samples representative of the entire flow.

O ne ommercially vailable n-stream device** counts nd

izes particles

n he

-250 micron ange.

The counter automatically draws a fluid sample from a hydraulic ystem hrough narrow assage itted with hotoelectric etection ystem. he ystem makes contamination data available in terms of number of articles n various ize anges per nit olume of ample.

Another on-stream utomatic ounter esign" allows for the automatic sampling, izing, and counting of particles greater in size than 0 microns. Measure- ments are accomplished by reflecting ultrasonic waves off contaminant articles.

6-2.4.2 Solid article Contamination Measurement by Weighing

Test Method: ASTM D-2387-65T (Ref. 2). This method overs he determination of insoluble

contamination in hydraulic fluids by gravimetric anal- yses. he ontamination etermined ncludes oth particulate and gel-like matter, organic and inorganic, which s etained n membrane ilter disk of pore diameter as required by applicable specifications (usually 0.45 micron r 0.80 micron).

The Cintel lying-Spot article esolver, ade y inema Television Co., London.

* Casella Automatic Particle Counter and Sizer. **HIAC Automatic Particle Counter.

**A ounter designed by Sperry Products Company or the Mar- shall Space Flight Center.

The insoluble contamination is determined by draw- ing a 100-ml sample of hydraulic fluid through a membrane filter disk and measuring the resultant ncrease in the weight of the filter. In addition, the filter disk is microscopically scanned for excessively large particles, fibers, or other unusual conditions.

Precision: Results should no t be considered suspect

unless they differ by more than the following amount: (a) epeatability. .2 mg/100 ml (b) eproducibility. .0 5 mg/100 ml

6-2.4.3 Solid article Contamination Measurement by Combined Counting and Weighing Methods

Many users of hydraulic fluids prefer to rely on more than ne echnique or etermining ontamination. The testing procedure required for MIL-H-5606B fluid is a good example. This particular fluid s considered below specification if it fails either a weight analysis or particle count test. According to weight, there must not be more than 0.3 mg of solid particle contaminants per 100 ml when the test is conducted under the provisions of Federal est ethod tandard o. 91a, est Method 00 9 Ref. 9). ccording o he article count', he number of contaminant particles must not exceed the values given n Table 6-6.

6-2.4.4 Liquid Contaminant Measurement

Determination of the mount of liquid ontamination present in a hydraulic fluid can become a difficult problem, specially f he ontaminant s oluble or miscible n he hydraulic luid. ince most means of measuring liquid contaminants involve chemical reactions, it is usually a prerequisite to know what kind of contaminants re eing measured o hat he proper reagents may be used. However, the problem is somewhat simplified since the most common liquid contaminant is water. Procedures for determining other types of contaminants re sually pecific o he hemical nature of the hydraulic fluid.

If the mount f water ontaminant resent n hydraulic luid s arge, echniques uch s dilution with olvent which will eparate he water nto n immiscible ayer an e sed. When he mount f water present s mall, wo procedures re enerally used. O ne depends upon the physical separation of water by means of an entraining nonsolvent and the other on a chemical eaction.

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TABLE 6-6.

SOLID PA RT I CL E CONTAMINATION LIMITS IN HYDRAULIC FLUID C O R R ES P O N D I N G T O MIL-H-5606B

Particle Size Range, n* Maximum Allowable Number of Solid Particles

5-15 2,500

16-25 1,000 26-50 250

51-100 50

Over 100 None

*M micron = 10" cm

(1 ) es t for Water in Petroleum and Other Bitumi- nous Materials:

Test Methods : Federal Test Method 3001.8 (Ref. 23)

ASTM D-95-62 Ref. 4) These methods are used to determine the water content of bituminous materials by distillation with a water immiscible, volatile solvent.

The ample s eated under eflux ith water- immiscible solvent which co-distills with the water in the sample. Condensed solvent and water are continuously separated in a trap, the water settling in the graduated section of the trap and the solvent returning to the still.

(2 ) es t for Water With Karl Fischer Reagent: Test Methods : Federal Test Method 253 Ref. 5)

~ STM D-1744-64 (Ref. 6)

These methods cover the procedures for determining water in the concentration of 50 to 1,000 ppm in liquid petroleum products. The procedure, referred to as the Karl ischer ethod, r ome ariation f t, s widely used fo r the determination of moisture content of many materials. Although the test standards list the procedure for petroleum products only, it can be used on most materials where the reagents will not produce reactions that iv e false eadings.

Sufficient Karl Fischer reagent is diluted with pyridine to adjust its strength to a water equivalence of 2 to 3 mg H20 per ml of solution. Fifty ml of the sample is diluted with 50 ml of methanol-chloroform (1 part to 3 parts by olume). The sample s then dded o he adjusted solution. f water is present, the solution will no onger e ry. econd djustment ith arl Fischer reagent is made until the water equivalence of 2 to 3 mg H20 per ml of solution is again reached. The amount of moisture present is then determined by the amount of reagent used to reach the second end point.

6-3 PRECAUTIONS

The exercise of certain precautions in the storage and

handling of hydraulic luids s ital or he afety of personnel and for the protection of the fluid. The introduction of contaminants nto he hydraulic luid nd contact ith ncompatible aterials re both o be avoided. Personal hazards from explosion, fire, skin poisoning, ingestive poisoning, and vapor inhalation are of even more oncern. Anyone who tores nd handles hydraulic fluids should know well the hazards they face and follow all ecommended afety precautions.

6-3.1 HEALTH H A Z A RD

Skin poisoning, ingestive poisoning, and exposure to vapors nd prays f hydraulic luids re ommon threats to hydraulic fluid handlers. Other dangers are due o he xplosive or highly lammable nature of some iquids. Most hydraulic luids, owever, do not pose a serious health hazard. For specific information on the hazardous nature of a particular fluid, the fluid manufacturer should be consulted.

6-3.1.1 Precautions Against Poisoning

Skin poisoning or irritation caused by repeated han-

dling f ydraulic luid, nd ngestive oisoning caused by accidental swallowing are two hazards that can e asily guarded gainst. he wallowing of a hydraulic luid s ery are. onetheless, oisonous hydraulic fluids should be clearly marked as such and an ntidote r ther irst id rocedure hould e known from the manufacturer's data or from cautionary

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AMCP 706-123

information n he luid ontainer. For ll ydraulic luids, he avoidance of extended contact with he skin is recommended. Although most hydraulic fluids, including synthetics, are not harmful to bare skin, prolonged contact should be avoided because many of the ingredients and additives may tend to dry ou t the skin. However, he ffect s sually ot on g asting f the

exposure is ot rolonged.

6-3.1.2 Precautions Against Dangerous Vapors an d Sprays

Vapors nd mists rom many hydraulic luids re generally rritating nd ause oughing or neezing. For hese easons prolonged nhalation of hydraulic fluid vapors or sprays is to be avoided. Even when the effects of short xposures re known o e nontoxic, indirect damage to the respiratory system could occur because of frequent or repeated irritations. Vapors from hydraulic fluids are most irritating when the fluid is at high emperatures, s he luid may decompose nd give off toxic vapors. Then, and at all times, the general rule is to avoid vapors from hydraulic fluids by working in well ventilated areas or by wearing protective masks.

coupling)-can spray system components and surround- ings hat may be hot nough to cause ignition. f the liquid s onducting, he pray an lso ause hort circuits in electrical systems which, n turn, can cause ignition. Precautions against this sort of fire hazard are the responsibility of the system designer. If possible, the probable points of system failure should be situated so

that, should a leak occur, the hydraulic spray will not be exposed to potential gnition sources.

6-3.3 OTHER PRECAUTIONS

Additional areas requiring precautions pertain to the relationship of hydraulic fluids with other materials.

All ydraulic luids re ncompatible ith om e materials. The esigner akes his into ccount when choosing system components and a hydraulic fluid fo r the system. On occasion, however, users of a hydraulic system may desire to use a different hydraulic fluid. In changing to a different fluid, on e should always investi- gate he afety of the hange horoughly. f the ew fluid is incompatible with an y system component, even- tual ystem malfunction is probable. The fluid manufacturer can supply data n ompatibility of his fluid with ommonly se d ystem materials.

6-3.2 DANGER OF EXPLOSION ND IR E REFERENCES

The danger due o xplosion of hydraulic luids s possible during storage, handling, or use in a hydraulic system. The explosive limits" of a substance are the

lowest and highest concentrations of the vapors of the substance in the atmosphere which will form a flammable mixture (Ref. 7). Hydraulic fluids hould not e stored where the temperature may become high enough to ignite the fluid. A common precaution hat hould be aken s o tore he ydraulic luid n n rea removed from all possible sources of ignition and fromareas where personnel or equipment would be endan- gered should the stored liquids be accidentally ignited.

Fire and explosion precautions are even more important in direct handling of hydraulic fluids. Pouring or draining of fluids near sources of ignition (such as direct lames or hot urfaces) s nviting disaster. Even fire-resistant fluids can ignite and continue to support flame if conditions are favorable (Ref. 8).

Serious fire hazards can occur when a liquid is in use in a hydraulic system. Because of the high pressure in components of the system, flammable hydraulic fluids in he vent of ystem ailure broken ose, ine,

1 . PP-C-96A, Cans, Metals, 28 Gage and Lighter, 6 October 964.

2. PP-D-729B, rums: etal, 5-Gallon For Shipment ofNoncorrosive Material), 9 August

1958. 3 . PP-P-704B, ails, etal: Shipping, teel,

Through 12 Gallon), 0 February 967. 4. T-E-515, namel, lkyd, ustreless, uick-

Drying, 2 December 963. 5. IL-STD-290C, ackaging, acking, nd

Marking of Petroleum and Related Products, 24 M ay 965.

6. IL-H-5606B, ydraulic luid, etroleum Base; Aircraft, Missile, and Ordnance, 6 June 1963.

7. IL-H-8446B, Hydraulic Fluid, Nonpetroleum Base, Aircraft, 2 March 959.

8.

T-I-558, nk, arking, tencil, paque, or Nonporous urfaces Metals, lass, tc.), 2 June 957.

9. T-L-20, acquer, amouflage, July 963. 10. T-E-489, Enamel, Alkyd, Gloss, For Exterior

and Interior Surfaces), 0 September 965.

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A M C P 706-123

11 .

12 .

13 .

14 .

15 .

16.

17.

MIL-H-27601, Petroleum Base, High Tempera- ture, Flight Vehicle, 3 anuary 964. T. N. Deane, "The Effect of Contamination on

9.

Fluids and the Effect of the ngredients of the Fluids on Contamination", Proceedings of

0.

Aerospace Fluid Power Systems and Equipment Conference-May 1965, Society of Automotive

Engineers, New York, 965.

1. J. Messina nd A . Mertwoy, Inorganic alts

in Mahogany ulfonates nd heir Effect n Petroleum ydraulic luids", ub. ng., Feb. 967. R. E. Hatton, ntroduction to Hydraulic Fluids,

2.

Reinhold Publishing Corp., N.Y., 962. M. Piccone, "Control of ontamination in Rocket Booster Hydraulic Systems", roceed-

3.

ings f Aerospace luid ower ystems nd Equipment onference-May 965, ociety f

4.

Automotive Engineers, N ew York (1965). S. A. London, "Microbial Activity in Air Force

Je t ue l Systems", Developments in ndustrial

5.

Microbiology , 2 1964). H . . Huggett, Servo Valve Internal Leakage 6. as Affected by Contamination", Proceedings of Aerospace Fluid Power Systems and Equipment Conference-May 1965, Society of Automotive

7.

Engineers, New York 1965). D . . enny, Cleanliness n ydraulic ys-

8.

terns", Proceedings of the Conference on Oil Hy- draulic Power Transmission and Control-

November 1961, Institution of Mechanical Engineers, London 1962). Federal Test Method Standard No . 91a, Test Method 009. ASTM Standards 967, esignation -2390- 65T, Part 8, . 33 , Philadelphia, American Society or Testing Materials, 967.

Procedure for th e Determination of Paniculate Contamination of Hydraulic Fluids by th e Parti- cle Count Method, Aeronautical Recommended Practice 598, Society of Automotive Engineers, Inc., New York, N.Y. p. -6 (1960). ASTM Standards 967, esignation -2387- 65T, Part 8, pp . 510-513, Philadelphia, Ameri- can ociety for Testing Materials, 967. Federal Test Method Standard No . 91a, Test Method 001.8. ASTM Standards 1967, Designation -95-62, Part 7, . 5, Philadelphia, American Society for Testing Materials 967. Federal Test Method Standard No . 91a, Test Method 253. ASTM Standards 1967, Designation D-1744-64, Part 7, p. 667, Philadelphia, American Society fo r Testing Materials, 967. Accident Prevention Handbook AFM 32-3, D e- partment of the Air orce, August 964. H . M. Shiefer, "For Hydraulic Systems, Drives, Dashpots: What's Hot in Fluids?" Product En- gineer, 07 , August 964.

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AMCP 706-123

G L O S S A RY

accumulator

bladder-type

diaphragm- type

nonseparator- type

piston-type

spring-loaded

weight-loaded

acid number

actuator

additive

bypass

cavitation

autoignition temperature (A IT) base umber

A fluid pressure storage chamber in which luid pressure nergy ay be stored and from which it may be withdrawn.

A hydropneumatic accumulator in boiling point which the liquid and gas are separated by an expandable bladder or elastic ba §

ulk odulus

A hydropneumatic accumulator in which the liquid and gas are separated by a flexible diaphragm.

An ccumulator n which om - pressed gas operates directly upon the liquid in the pressure chamber.

An ccumulator n which ompressed as operates n iston which pplies orce o he tored liquid.

An accumulator in which the compression nergy s upplied y

spring. An ccumulator n which weights apply force to the stored iquid.

The quantity of base, xpressed n milligrams f potassium ydrox- ide, hat s equired o neutralize the acidic constituents in on e gram of sample.

A evice o onvert luid nergy into mechanical motion.

A hemical ompound r om - pounds added to a liquid to change

its properties. The temperature at which a liquid placed on a heated surface will ignite spontaneously.

The mount of acid, xpressed n control terms of the equivalent number of

centipoise

centistoke

cloud point

coefficient f expansion

compressibility

milligrams f potassium ydrox- ide, required to neutralize all basic constituents present in on e gram of sample.

The emperature t hich luid refluxes or distills under carefully specified conditions.

The reciprocal of compressibility. It

is usually

expressed in

pounds per

square inch. An lternate oute which provides passage for a liquid around a component.

A henomenon f ormation f cavities n iquid cross hich the iquid an ov e ith igh velocity, producing hammer f- fect on an y object it strikes. It usually occurs where pressure s ow and velocity high. Cavitation generally causes noise and damage to system components.

A unit of absolute iscosity. A unit of kinematic viscosity.

The emperature t which wax or other dissolved solids first precipitate during chilling under specified conditions.

The hange n eight er nit volume pe r ° change of temperature.

The reduction in volume of a liquid

when ressure s pplied. ompressibility is usually measured in terms of the bulk modulus, which is the reciprocal of compressibility.

A device used to regulate the functions of a component or system to

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A MCP 706-123

automatic

electric

hydraulic

liquid-level

mechanical

pneumatic

which it is usually connected; may be integral or remote.

A control actuated in response to a signal from the system; also a control which actuates equipment in a predetermined manner.

A control actuated by an electrical device.

A control ctuated y iquid ressure.

A device which controls the liquid level, uch s a float witch.

A ontrol ctuated y inkages, cams, ears, crews, or other mechanical means.

A ontrol ctuated y ir or other gas pressure.

pump

ontrols applied to hydraulic

pumps to adjust their output or direction of flow. servo ontrol ctuated y eed-back

system which compares the output with he eference ignal nd makes orrections o educe he difference.

conduct ion

rocess by which heat flows from a region of higher temperature to a region of lower temperature within a edium r etween ifferent media in direct physical ontact.

convection

ransference f eat y moving masses of matter.

cylinder device fo r converting fluid energy into linear motion. t usually consists of a movable element such as a piston and piston rod, plunger or ram operating within a cylindrical bore.

double-acting ylinder which moves n ither direction ue o luid low nd pressure.

double-end A cylinder with a single piston and

rod

ith od xtending rom ach end.

piston-type ylinder n hich he movable element as reater ross-sectional rea than he piston od.

G-2

plunger-type; ylinder n which he movable element as he am e ross-sectional area as the piston od .

single-acting cylinder in which the fluid pressure s pplied n nly ne irection.

single-end A ylinder ith od xtending rod

ro m ne end.

density he mass of a material occupying unit volume at a specified temperature. ts dimensions are mass per unit volume.

elastomer

n elastic, ubber-like material.

emulsion

n intimate dispersion of on e liquid within another.

film trength The ability of a liquid to maintain a film.

filter

evice through which fluid is

passed to separate material held in suspension. he ilter medium s tie aterial hich emoves he solids nd onsists f aterials such as paper, loth, inely woven screen, intered metals, inely i- vided solids such as clay, activated charcoal, tc.

bypass

filter which eceives only a portion of the otal luid low. on - tinuous mixing of the filtered and unfiltered fluid ensures that it is all eventually filtered in a easonable

period of time. The temperature at which iquid will urn ontinuously he n g- nited by a small flame under carefully pecified conditions.

A fluid difficult to ignite and which shows little tendency to propagate flame.

The temperature at which liquid gives off sufficient lammable a- pors o gnite but not ontinue to burn when approached by a small

flame

nder

arefully

pecified conditions. flow, aminar low ituation n which motion

occurs as a movement of one layer of fluid upon another. This is syn- onymous with streamline flow.

fire oint

fire-resistant fluid

flash oint

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AMCP 706-123

f low, teady state

f low, treamline

f low, urbulent

flow ate

flow elocity

fluid

halogenated- type

hydraulic

organic ster- type

petroleum- type

phosphate ester -type

polyalkylene glycol- type

silicate ster- type

silicone-type

water-glycol- type

water-oil emulsion type

A flow situation wherein conditions

ynthetic such as pressure, temperature, and velocity at every point in the fluid do not change.

A low ituation n which motion occurs as a movement of one layer of fluid upon another. This is syn- onymous with laminar flow.

A flow situation in which the liquid particles move n andom manner.

The unit volume of a fluid flowing per unit of time.

The rate of speed at which a volumeof fluid passes a particular point in a passage.

A ubstance hich ields o ny pressure tending to alter its shape. Fluid, by strict definition, includes

both iquid and as. A luid omposed f halogenated organic materials and which may contain dditional mounts f other constituents.

A fluid suitable for use in hydraulic systems.

A luid omposed of esters of carbon, ydrogen, nd xygen, nd which ay ontain dditional amounts of other constituents.

A fluid composed of petroleum hydrocarbons nd hich ay on - tain dditional mounts of other constituents.

A fluid composed of phosphate esters and which may contain additional mounts of other constituents.

A luid omposed f olyalkylene lycols r erivatives nd which may ontain dditional - mounts of other constituents.

A luid omposed f organic ilicates and which may contain additional mounts of other onstituents. A luid omposed of silicones nd which may contain additional hose amounts of other constituents.

fluid ower

fluid ower system

foam

freezing oint

friction

heat xhanger

A material which, y definition, s nonpetroleum, ut hich ay contain nonfunctional amounts of petroleum. pecifically, his ermits petroleum to be used as a carrier or onstituent, .e., or n additive, tc., ut xcludes e-

troleum used for an y benefit of its properties per se.

A luid hose major onstituents are water and on e or more glycols or polyglycols and which may contain dditional mounts f other constituents.

A tabilized mulsion f ater -oil, nd hich ay ontain d- ditional amounts of other constituents. here re wo ypes: 1) oil-in-water, onventional oluble oil in which oil s dispersed in a ontinuous phase of water; nd (2 ) water-in-oil, a dispersion of water in a continuous phase of oil.

Power ransmitted nd ontrolled through use of a pressurized fluid.

A ystem hat ransmits nd on - trols power through use of a pressurized fluid within an enclosed circuit.

An intimate mixture of gas and liquid occupying much more volume

than he liquid alone. The emperature t hich luid changes from liquid phase to solid phase.

Resistance to motion. Fluid friction is that friction due to the viscosity of the fluid.

A device for transferring heat froma hot luid to a cold ne , without the wo oming n ontact ith each other. When se d s luid cooler n ydraulic ystem, t may take the form of either a nest of ipes n uitable ontainer, through which coolant flows, or a radiator.

A lexible onduit or onveying fluid.

G-3

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A MC P 706-123

hydraulic power system

hydropneumat ic

inhibitor

intensifier

isentropic

isothermal

leaching

motor

fixed displacement

oscillatory

rotary

variable displacement

neutralization number

O-ring

G-4

A means of energy transmission in which elatively ncompressible liquid hydraulic luid) s se d s an nergy-transmitting medium.

The ombination of hydraulic nd pneumatic power in a nit.

Any ubstance hich lows, re - vents, r modifies hemical eactions uc h s orrosion or xidation.

A device which increases the working pressure over that delivered by a rimary ource. or xample, such a device is on e in which a low pressure acts on a large piston di - rectly coupled to a smaller piston which then produces a higher pressure.

Having he am e properties n ll

directions. Describing a condition of constant temperature.

An operation n which he soluble component of a solid phase is dissolved nd ransferred o iquid solvent.

A device for converting fluid energy into mechanical motion.

A otary motor n which he isplacement per revolution is fixed.

A rotary actuator giving an angular

movement of less than 360°, sometimes eferred o s otary y- draulic actuator.

A motor producing continuous ro - tary motion.

A otary motor n which he isplacement per revolution is adjustable.

A measure of the acidity or basicity of a iquid. t s defined s milligrams of potassium hydroxide e- quired to neutralize the acidity n

one gram of fluid or the equivalent of the basicity expressed in a similar manner.

An endless packing ring of circular cross section normally mounted in a groove in such a manner that the

oxidation

packing

pilot in e

piping

piston ing

poise

por t

pour oint

pressure

absolute

atmospheric

operating

static

suction

pressure drop

pressure o ss

effectiveness f ealing ncreases with the pressure.

A chemical reaction of oxygen with a liquid, resulting in the formation of oxidation products, which an cause changes in properties.

Any material or device used to prevent eakage. Packings, eals, nd gaskets re ften onsidered yn - onymous.

A tube or hose which conducts control fluid.

All pipe, ubing, hose, and fittings.

A ealing ing which normally its in rooves in the piston ead.

The tandard unit of absolute iscosity n he entimeter-gram- second ystem. t s xpressed n dyne seconds per square centimeter.

An opening at a surface of a component, .g., he erminus of a assage. t may be nternal or xternal.

The lowest temperature at which a liquid will flow under specific conditions.

Force per nit rea. t s sually expressed n ounds er quare inch.

The um of atmospheric nd ag e pressure.

Pressure exerted by the atmosphere at ny pecific ocation. ea evel atmospheric ressure s pproximately 4.7 sia.

The pressure t which ystem s operated.

The pressure hat xists f there s no motion n he liquid.

The pressure of the liquid at the in- le t of a pump.

The mount of pressure difference or he pressure equired o orce fluid through a component.

The fall in pressure due to hydraulic friction in a component or circuit.

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AMCP 706-1 23

pump

axial iston constant

volume

axial iston variable volume centrifugal

gear

radial iston constant volume radial iston variable volume

reciprocating

screw

two-stage

vane, onstant volume

vane, ariable volume pump l ippage

radiation

Pressure osses t ull low re often ppreciable; here s, ow - ever, none when low eases.

A evice which onverts mechani- ca l energy into fluid energy. A ump ith ixed volumetric output nd with ultiple istons having heir xis arallel o he drive shaft.

An xial iston ump ith n adjustable ontrolled volumetric output.

A pump having an impeller rotating in ousing ith iquid arried around the periphery of the housing nd ischarged y eans f centrifugal orce.

A pump having two or more inter- meshing ears or obed members

enclosed in a suitably shaped housing.

A ump ith ixed olumetric output aving ultiple istons disposed radially.

A adial iston ump ith n adjustable volumetric output.

A pump aving eciprocating istons to pressurize fluid.

A pump having on e or more screws rotating n housing.

A pump with tw o separate pumping elements connected in a series. The primary tage may e se d to en- sure that the second main stage is not starved for fluid, or it may produce uch f he ressure ise through he pump.

A ump aving ixed volumetric utput ith ultiple anes within upporting otor, encased in a cam ing.

A vane pump having suitable means of changing he volumetric output.

Internal eakage n ump rom outlet o inlet ide.

The rocess y hich eat lows from a high-temperature body to a

reservoir

Reynolds number

seal

servomechanism

solenoid

specific ravity

specific heat

stability

hydrolytic

oxidation

thermal

body at a lower temperature when the bodies are separated n pace, even he n acuum xists e- tween hem.

A ontainer or luid rom hich the luid s ithdrawn nd e- turned fter irculation hrough

the ystem. The eservoir may e open to the atmosphere, or it may be closed and pressurized.

A imensionless umber se d n considerations f luid low nd given y he ormula: n

(Velocity) pipe iameter) Kinematic iscosity. hen he Reynolds number s elow ,000, laminar low enerally xists; t higher alues, low may be either laminar r urbulent, ut he higher the value the less likely the

flow will be aminar.

A aterial r evice esigned o prevent eakage etween arts, moving or static.

A ny mechanism which ses power magnification nd n which here is incorporated a means of relating the peed nd ravel of the nput and output.

An lectromagnet onsisting f wire-wound oil ith oving plunger hich oves he n he electric current s switched on .

The atio of the weight of a iven volume of fluid to the weight of an equal olume of water.

The heat equired o aise nit weight one degree of temperature.

Resistance to permanent changes in properties nder ormal torage and se conditions.

Resistance to permanent change in properties aused y hemical

reaction with water. Resistance to permanent changes in properties aused y hemical reaction with xygen.

Resistance to permanent changes in properties caused solely by heat.

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A MCP 706-123

stoke

strainer

switch, pressure

thermostat

torque

vacuum

valve

cam-operated

check

closed enter

directional

flow ontrol

flow ividing

flow ividing, pressure compensating type

four-way

The standard unit of kinematic viscosity n he entimeter-gram- second ystem. t s xpressed n square centimeters per second.

A ilter made from wire mesh nd capable of removing the larger particles of solids from fluid.

A switch operated by pressure and used or a) ontrolling ressure between predetermined imits, b) starting r topping equence when a certain pressure is reached, and c) s a safety evice.

A evice or ontrolling emperature either by switching on and off an lectric urrent or y opening and closing a valve in a liquid line.

Force applied through a rotary path of motion.

A pressure which s ess han he prevailing atmospheric pressure.

A evice for controlling flow ate, direction of flow, or pressure of a liquid.

A alve in which he spool is posi- tioned mechanically by a cam.

A valve which permits flow of fluid in ne irection nly nd elf closes o prevent ny low n he opposite direction.

A valve which in the center position

ha s all ports closed. A alve whose primary function is to direct or prevent low hrough selected assages.

A valve whose primary function is to control flow ate.

A valve which divides the flow from a ingle ource nto wo or m o r e branches.

A alve hich ivides he lo w from ingle ource nto wo r more branches t onstant atio, regardless of the difference in the resistances of the branches.

A alve aving our ontrolled working assages, sually nding in our external ports.

gate valve with a gate which is raised or lowered by the action of a screw or other means to close or open the flow assage.

globe

alve with lug, all, or disc, which by action of a screw or other means, is pulled away from or low-

ered nto orresponding eat o open or close the flow assage. needle valve with a tapered needle which

is pulled away from or forced into a corresponding seat. The tapered needle permits gradual opening or closing of the passage.

open enter valve which in the center position connects all ports.

pilot

valve applied to operate another valve or control.

pilot-operated alve n hich perating arts

are actuated by ilot luid. poppet-type alve construction which loses

off flow by a poppet seating against a uitable eating aterial. or- mally considered a dead-tight seal. The poppet may be a ball, a cone, or a flat disk.

pressure

valve which maintains a reduced reducing

ressure at its outlet regardless of

the higher inlet pressure. relief

alve hich pens hen et pressure is reached to prevent fur-

ther rise of pressure in a system or to keep the pressure constant. The relief valve imits pressure which can e pplied o hat portion of the circuit to which it is attached.

sequence

valve which directs flow to a secondary portion of a fluid circuit in sequence. low is directed only to that art f he ircuit hich s connected o he primary or nlet port of the valve until the pressure setting of the valve is reached. At this time, the valve opens and pres-

sure n he econdary ort ay

vary from zero to near the setting of the primary side with no variation n he primary oressure.

shuttle onnective alve hich elects on e of tw o or more circuits because

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AMCP 706-123

flow or pressure changes between the circuits.

solenoid-

valve which is operated by on e or operated

ore solenoids.

spool-type

valve construction sing a spool consisting of undercuts or recesses on a cylinder of metal. The spool is fitted in a bore containing annular undercuts. Movement of the spool in the bore connects ports uncov- ered by he spool undercuts.

three-position alve having hree positions o give three selections of flow conditions.

three-way

directional ontrol alve having three distinctive external working connections.

two-position valve having tw o positions to give tw o selections of flow onditions.

two-way

directional ontrol alve having

tw o istinctive xternal orking connections.

unloading alve which llows pressure o build up o n djustable etting, then ypasses he low s on g s the preset pressure s maintained on he ilot ort y emote source. ts primary unction s o unload a pump.

time elay

valve in which the change of flow occurs only after a desired time interval has elapsed.

vapor pressure he pressure exerted by a material under consideration t a specified temperature.

venturi local contraction in a pipe which is shaped so that he oss of pressure due to friction is reduced to a

viscometer

viscosity

absolute

kinematic

Saybolt Universal Seconds (SUS)

Viscosity ndex (V.l.)

volatility

minimum. s he elocity n- creases t he Venturi hroat, he pressure ecreases ppreciably. Venturi ubes re ften se d s flow meters, the difference of pressure etween he ntrance o he Venturi and the throat varying as the square of flow.

A device for measuring viscosity.

A measure of the internal friction or the resistance of a fluid to flow.

The force required to move a plane surface over another plane surface at he ate of on e entimeter per second when he surfaces re ne centimeter quare nd re eparated by a layer of fluid on e centimeter n hickness. his orce s known s he poise.

The atio f bsolute iscosity o the density of a fluid. The unit of kinematic iscosity s he toke. Viscosity n tokes, ultipled y density t he est emperature equals he bsolute iscosity n poise. Saybolt Universal Second viscosity is the time in seconds required for 60 cc of liquid o flow through a standard orifice t a given emperature.

A measure of the viscosity-temperature characteristics of a fluid as re - ferred to that of other fluids.

The property of a luid describing the degree to which it will vaporize under given conditions oftempera- ture and pressure.

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AMCP 706-123

INDEX absolute viscosity, 3-2

accumulators, 2-21 pneumatic-loaded, 2-22 , -2 3 spring-loaded, 2-22 , 2-23 weight-loaded, 2-22 selection considerations, 2-23

accuracy, 1-5

acid number strong, 3-71 total, 3-71

actuators, 2-9 cushioned, 2-11 cylinder, 2-10 kinematics of , 2-11 linear, 2-9 mounting configurations, 2-11 noncushioned, 2-11 nonrotating, 2-9 piston or plunger, 2-9 rod type, 2-10 rotating, 2-9 tandem, 2-10

actuator, rotary, 2-9, 2-14

actuators, valve, 2-31 cam, 2-31 manual, 2-31 pilot fluid, 2-32 servomechanism, 2-32 spring, 2-31

additives, 3-60, -1 antirust, 3-60 antiwear, 3-60, -8 , -9 for aryl ether fluids, 5-10 for mineral oils an d esters, 5- 9 for silicone fluids, 5-9 hydrolytic inhibitors, 5-10

pour point depressants, 5-10 seal degradation retardants, 5-10

AIT, 3-27

alkalinity, 3-70

alky aryl phosphate ester, 4-7

Almen tester, 3-61

antioxidants, -1 classes of, -2 fo r esters, -2 fo r ethers, 5-3 fo r highly refined mineral oils, 5- 3 fo r siliconcontaining fluids, 5-3 mode of action, 5-1 synergistic effect, 5- 2

antiwear additives, 3-60, -8 , -9

API Gravity, 3-40

Aroclor, 4- 9

ASTM Color, 3-70

ASTM slope, 3-9

autoignition temperature, 3-27

availability, 1-6

axial-piston motors, 2-16

axial-piston pumps, 2-6

back-pressure valve, 2-27

baffles, 2-19

balanced vane pump, 2-6-

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A MC P 706-123

base number, 3-71 strong base number, 3-71 total base number, 3-71

bellows pump, 2-8

bench ests, 3-61

beverage bottle test, 3-74

Bingham pycnometer, 3-41

biocides, 5-11

bladders, 2-23

blends, viscosity of, 3-14

boilingpoint, 3-32

boundary lubrication, 3-57, -58, -8

bulk modulus, 1-6, -44, -4 5 estimation of , 3-49 isentropic secant, 3-46 isentropic tangent, 3-46 isothermal secant, 3-45 isothermal tangent, 3-46 secant, 3-45 tangent, 3-46

Buna S rubber, 3-85

butyl rubber, 3-85

butadiene rubber, 3-85

by-passreliefs, 2-19

calibration, viscometer, 3-8

Cannon-Fenske viscometer, 3-7, -8

Cannon-Master viscometer, 3- 8

capillary viscometer, 3-6, -7

caster oils, 4-6, -10

cavitation, 3-18, -5 4 damage, 3-81,, -82 factors causing, 3-82 general, 3-81

1 -2

inhibitors, 5-10

Cellulube FRYQUEL), 4-8

centipoise, 3- 3

centistoke, 3-3

centrifuge, 1-7

check valves, 2-6, -28

chemical corrosion, 3-75

chemical stability, 3-65

chloroprene rubber, 3-85

chlorosulfonated polyethylene, 3-85

circuits, fluid power, 1-2

circuit, rotary liquid motor, 2-2

classification, 4-1 chemical properties, 4-1 fire resistance, 4-2 operating characteristics, 4-2 physical properties, 4-1 Types I-VI, 4-2 viscosity, 4- 1

Cleveland open cup, 3-22

cloud point, 3-20 significance, 3-22 test for, 3-21

coatings, containers, 6-1

coefficient of friction, 3-57,3-61

coefficient of cubical expansion, 3-40

coefficient, viscosity-temperature, 3-11

coke, -7 2

color, -70

color-indicator itration, 3-71

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AMCP 706-123

compatibility, 1-4, -21, -79 test for, 3-94 with additives, 3-96 with metals, 3-80 with other lubricants, 3-93, -1 with paints, 3-93 with solid film lubricants, 3-95

compressibility, 1-5, -4 4

compression ignition tests, 3-26

conduction, 2-35

Conradson test, 3-72

containers, 6-1 coating, 6-1 liners, 6-1 marking, 6-1

materials, 6-1 sizes, 6-1 storage, 6-1

contaminants, 6-3 dust, 6- 3 lint, 6-3 liquids, 6-6 microbiological, 6- 7 particles, 6-6 sources, 6-3 types, 6-5 water, 6-5

contamination, 1-7 automatic counting, 6- 9 effect on oxidation, 3-66 effects, 6-8 hydraulic fluids, 1-7, -8 liquid, 6-10 measurement, 6-9, -10 microbiological, 6- 7 sedimentation, 3-56 weighing of , 6-10

controls, directional, 2-2 pressure, 2-2

convection, 2-35

conversionunits, viscosity, 3-3, -8

cooling systems, 2-36 air-cooled, 2-37 water-cooled, 2-37

corrosion, 3-67, -75, -8 1 cause of metal fatigue, 3-81 chemical, 3-75

copper strip test, 3-76 corrosion-fog cabinet test, 3-76 electrochemical, 3-75 metal-liquid test, 3-76 oxidation-corrosion, 3-72, -74, -1 protection-salt spray test, 3-76

corrosion inhibitors, 5- 4 limitations of, 5- 4 mode of action, 5-4 volatile corrosion inhibitors, 5-5

couplings, 2-9, -39

crescent seal motors, 2-14

crescent seal pumps, 2-4

crystallization, 3-56

cushioned actuators, 2-11

cylinder-type actuators, 2-10

deactivators, etal, 5-2

demulsifiers, 5-7, -8

density, 3-35, -3 6 pressure dependence, 3-36 temperature dependence, 3-36

di-2-ethylhexyl sebacate, 5-2, -4

diaphragm pump, 2-8

dilatant fluid, 3-5

dilu te d pour point, 3-21

Dornte oxidation test, 3-73

elastomers, 3-83 compatibility with seals, 3-79, -83 materials, 3-84 test for compatibility, 3-92

1-3

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AMCP 706-1 23

electrochemical corrosion, 3-75

electronic equipment coolant, 4- 5

emulsifiers, 5-7, -8

emulsions, 1-7, -51, -52,4-2, 4-7

energy, 1-1

Engler, 3-3, -4

esters, 5- 2 organic acid, 4-5, -10 phosphate, 4-2, -3 , -7 , -10 silicate, 4-2, -5, -10

ethers, 5- 9 polyphenyl, 3-66, -69, -2 , -9, -10

ethylene propylene rubber, 3-85

evaporation, 3-33, -34, -35, -73

evaporation-oxidation tests, 3-73

explosions, 6-12

extreme pressure, 3-59 additives, 5-8, -9

Falex tester, 3-61

fatigue, 3-81

film strength, 3-59

filters, 1-7, -1 9 absorbent, 2-20 adsorbent, 2-20 cleaning an d replacement, 2-21 compatibility, 2-21 mechanical, 2-19 pressure drop, 2-21

fire point, 3-22, -2 4

fire resistance, 3-28, -2 emulsions, 3-28 synthetics, 3-28 water-glycol, 3-28

fittings, 2-37

1 -4

flammability, 3-22 tests for, 3-24

flapper valve, 2-24

flashpoint, 3-22, -2 4

flow-dividing valves, 2-24, -3 1

fluids, non-Newtonian, 3- 4

fluid power 1-2 circuits, 2-2 generation, 1-2 uses, 1-3

fluorocarbon rubber, 3-85

fluorolube, 4-9

fluorosilicone rubber, 3-87

foam, 3-51 foaming tendency, 3-52 foam stability, 3-52 test for, -5 2

foam inhibitors, 5-1, -7 mode of action, 5-7 types of , 5- 7

fog cabinet, 3-76

four-ball ester, 3-62

Fourier's Law, 2-35

free radical acceptors, 5- 2

freezing point, 3-20

FRYQUEL (Cellulube), 4- 8

fuze, hydraulic, 2-28

gas solubility, 3-54

gas turbine lubricant, 4-5

gear fatigue tests, 3-64

gear pumps, 2-3

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A MC P 706-123

gear motors, 2-14

gelling, 3-56

gerotor motor, 2-14

gerotor pump, 2-4

globe valve, 2-30

glossary, G-l

glycols, 4-5, -1 0 polyalkylene, 4-2, -6 polyoxyalkylene, 4-6 polyoxyethylene, 4-6 polyoxypropylene, 4-6 water, 4-6

halogenated fluids, 4-8

handling, 1-6 compatibility, 6-12 explosions, 6-12 fire, 6-12 health hazards, 6-11 poisoning, 6-11 precautions, 6-11

heat exchangers, 2-35 air-cooled, 2-37 water-cooled, 2-37

heat transfer, 2-35, -4 2 conduction, 2-35 convection, 2-35 radiation, 2-35

heat transfer coefficient, 2-36

heat-transfer fluid, 4-5

helical gear pumps, 2-4

herringbone gearpumps, 2-4

heterocyclic compounds, 4-9

high-pressure spray ignition, 3-24

hot manifold spray ignition, 3-24

Houghto-Safe, 4-8

hydraulic fluids, 1-4 classification, 4-1 Specification fluids

JAN-F-461, 4-48, -4 9 W-B-680a, 4-48, -52, -5 3 W-L800, 4-10, -1 1 W-D-001078, 4-44,4-45

MIL-L-2104B, 4-10, -1 2 MIL-H-5559A, 4-44, -46 MIL-H-5606B, 4-13, -14 MIL-H-6083C, 4-13 MIL-L-6085A, 2-35, -39 MIL-L-7808G, 4-40, -4 1 MIL-H-8446B, 4-35,4-38 MIS-10137, 4-13, -1 6 MIS-10150, 4-17, -1 8 MIL-L-10295A, MIL-H-13866B, MIL-H-13910B, MIL-H-13919B,

4-17, -1 9 4-17, -2 0 4-48, -50, -5 1 4-21 , -22

MIL-F-17111, -21, -23,4-59, -69 MIL-L-17331F, -21, -24 MIL-H7672B, -21, -2 5 MIL-H-19457B, -35, -3 7 MIL-L-21260A, -26, -27 MIL-H-22072A, -48, -5 4 MIL-L-23699A, -40, 42 MIL-F-25598, -26, -2 8 M1LH-27601A, 4-26, -27, 4-28 MIL-L-45199A, 4-26, -30 MIL-H-46001A, 4-31, -32 MIL-L-46002, 4-31, -3 3 MIL-H-46004, 4-31, -3 4 MIL-P-46046A, 4-44, -4 7 MIL-H-81019, 4-35, -3 6 MIL-S-81087A, 4-40, -43

hydraulic fluid stability, 1-5

hydraulic fluid types, 4-1

hydraulic fuze, 2-28

hydraulic power, 1-1

hydraulic system types, 4-2

hydrocarbons, 4-2, -8

hydrodynamic lubrication, 3-57, -8

hydrolytic inhibitors, 5-10

1- 5

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AMCP 706-123

hydrolytic stability, 3-67, -7 4

hydrometer, 3-41

impurities, 5- 5

incendiary gun fire test, 3-26

inhibitors cavitation, 5-11 corrosion, 5-1, -4, -5 , -1 5 foam, 5-1, -7 hydrolytic, 5-10 oxidation, 5-1

insoluble material formation, 1-6

instrument lubricant, 4- 5

intensifiers, 2-17

isoprene, 3-85

jet-pipe valves, 2-24

Kel-F, 4-8

kinematic viscosity, 3-3, -6, -7

lacquer formation, 1-6

leaching, 5-5

liners, container, 6-1

Lipkin pycnometer, 3-40

liquid containers, 6-1

liquid contamination, 6-10 Karl Fischer test, 6-11 test for water, 6-11

liquid metals, 4-2, -9

liquid springs, 2-44

liquids, non-Newtonian, 3-4

load-carrying tests, 3-64 aircraft turbine lubricant, 3-64 lubricating oils, 3-64

oils at 400° F, 3-64 steam turbine oils, 3-64

load-dividing valves, 2-27

loss coefficients, -39

low-pressure spray ignition, 3-24 low-temperature stability, 3-55

low-temperature properties, 3-18

lubrication, 3-57 boundary, 3-57, -5 8 extreme pressure, 3-59 hydrodynamic, 3-57

lubricity, 1-5, -59, -8

lubricity additives, 5-1, -9

marking, hydraulic fluid containers, 6-1 abbreviations, 6-3 cautions, 6-3 colors, 6-2 materials, 6- 2

microbiological contamination, 6-7

mineral oils, 3-66, -2 , -3

motors, 1-3, -2

crescent seal, 2-14 gear, 2-14 gerotor, 2-14 piston, axial, 2-16 piston, radial, 2-17 piston, rotary, 2-17 rotary, 2-14 spur gear, 2-14 vane, 2-15

natural rubber, 3-85

needle valves, 2-30

neutralization number, 3-70 by color-indicator titration, 3-71 by potentiometric titration, 3-71

Newtonian fluids, definition, 3-4

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AMCP 706-123

nitrile rubber, 3-85

non-Newtonian fluids, 3-4 dilatant, 3-5 plastic, 3-4 pseudoplastic, 3-4 rheopectic, 3-5 thixotropic, 3-5

noncushioned actuators, 2-11

nonrotating actuators, 2-9

oiliness, 3-59

organic acid esters, 4-5, -1 0

organic oils, 4- 6

orientation viscosity loss, 5-6

orifice, 3-7

Ostwald viscometer, 3-8

oxidation-corrosion test, 3-72, -76

oxidation inhibitors. 5-1

oxidation stability, 3-65, -68, -72, -73

Pensky-Martens Closed C up Tester, 3-23

perfluorinated liquids, 4-9

perfluoroalkylesters, 4-2

petroleum base liquids, 4-3, -7 , -1 0

phosphate esters, 4-2, -3, -7 , -1 0

phosphonitrilates, 4-9

pintle, 2-7, -1 7

pipe cleaner evaporation test, 3-27

piping, 2-38 couplings, 2-75 fittings, 2-39

piston pumps, 2-6

piston-type actuators, 2-9

plastic fluid, 3-4

pneumatic-loaded accumulators, 2-23

pneumatic power, 1-1

poise, 3- 3

poisoning, 6-11

polar fluids, 5- 5

polyacrylic rubber, 3-85

polyalkylene glycol, 4-2, -6

polyethers, 4-6

polyglycols, 4- 5

polyisoprene, 3-85

polyoxyalkylene glycols, 4-6, -10

polyoxyethylene glycols, 4- 6

polyphenyl ethers, 3-66, -69, -2 , -9 , -1 0

polysiloxanes, 4-5, -8 , -1 0

polysulfide, 3-85

polyurethane, 3-85

poppet alves, 2-23, -24, -2 9

port plates, 2-6

position valves, 2-28

positive-displacement metering valves, 2-31

potentiometric titration, 3-71

pour point, 3-20, -21 , -22 depressants, 5-10

power transmission, 1-1

precautions, 6-11

1-7

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AMCP 706-123

pressure-compensated valves, 2-30

pressure controls, 1-3

pressure drop, 2-38, -6

pressure surges, 2-39

pressure switch, 2-28

properties low-temperature, 3-18 lubrication, 3-57 physical, 3-2 viscosity-pressure, 3-14 viscosity-temperature, 3-8

pseudoplastic fluid, 3- 4

pumps, 2-3 axial-piston, 2-6 balanced vane, 2-12 bellows, 2-8 crescent seal, 2-4 diaphragm, 2-8 external gear, 2-3 gerotor, 2-4 helical gear, 2-4 herringbone gear, 2-4 internal gear, 2 -4 piston, 2-6 radial-piston, 2-7 reciprocating, 2-3 rotary, 2-3 rotating piston, 2-7 screw, 2-8 spur gear, 2-3 unbalanced vane, 2-5 vane, 2-5, -1 5

pump tests, 3-63

Pydraul, 4- 8

radial-piston motors, 2-17

radial-piston pumps, 2-7

radiation, 2-36

radiation resistance, 3-68, -7 4

Ramsbottom test, 3-72 1 -8

recoil mechanisms, 3-38

Redwood viscosity, 3-3

reflux tests, 3-74

regulator valves, 2-28

Reid vapor pressure, 3-32

relief valves, 2-2, -26, -27

reservoir, 2-2, -1 8

response speed, 1-5

reverse flow viscometer, 3-8

reyn, 3-3

Reynolds number, 3-6

rheopectic fluid, 3- 5

rod-type actuators, 2-10

rotary actuator, 2-19

rotary fluid motor, 2-14

rotary-piston motor, 2-17

rotating piston pumps, 2-7

rust inhibitors, 5-4

Ryder gear machine, 3-64

SA E tester, 3-63

Saybolt Furol viscosity, 3-3

Saybolt Universal viscosity, 3-3, -7, -9

Saybolt viscometer, 3-7

scission, 3-18

seal degradation retardants, 5-10

seatingvalves, 2-24

secant bulk modulus, 3-45

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AMCP 706-123

sedimentation, 3-56

separation, 3-56

sequencevalves, 2-27

servo valves, 3-68

shearing stress, 3-2

shock absorbers, 2-39, -4 4 hydraulic, 2-40 hydropneumatic, 2-41 liquid spring, 2-44 relevant fluid properties, 2-44

shuttle valves, 2-29

short tube viscometer, 3-6

silicate esters, 4-2, -5, -10

silicones, 3-66, -69, -87, -2 , 4-5, -3

silicone rubber, 3-87

Skydrol, 4- 8

sliding-spool valves, 2-24

slope, ASTM, 3-9

solid film lubricants, 3-95

solubility, gas, 3-54

sonic bulk modulus, 3-46, -48

specific gravity, 3-38, -40, -41

specific heat, 3-42

spray ignition tests, 3-24

spur gear pumps, 2-3

spring-loaded accumulators, 2-22

stability chemical, 3-65 hydrolytic, 3-67, -74 low-temperature, 3-55

oxidation, 3-65, -72, -73 thermal, 3-66, -7 3

stable pour point, 3-21

steam turbine oxidation test, 3-72

stoke, 3-3

storage, 1-6, -1

streamline flow, 3-4

strong acid number, 3-71

suspended level viscometer, 3-8

symbols, 1-2, -3

synergistic effect, 5- 2

tag closed cup ester, 3-22

tandem actuators, 2-10

tangent bulk modulus, 3-46

temperature, 1-4

temperature-viscosity charts, 3-9

temporary viscosity loss, 5-6

tertiary phosphate esters, 4- 7

testers, friction an d wear, 3-61 Almen, 3-61 Falex, 3-61 four-ball, 3-62 SAE, 3-63 Timken, 3-61

thermal conductivity, 3-42

thermal energy, 2-35

thermal expansion, 3-40

thermal stability, 3-66, -7 3

thermal stability test, 3-73

thin flim oxidation ests, -7 3

thixotropic fluid, 3- 5 1 -9

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AMCP 706-123

thixotropic viscosity loss, 5- 6

thrust cam, 2-6, -1 7

thrust ring, 2-17

time-delay valves, 2-30 Timken tester, 3-61

total acid number, 3-71

total base number, 3-71

toxicity, 1-6

transducer, 2-32

transmission, fluid, 2-17

trialkyl phosphate ester, 4-8

triaryl phosphate ester, 4-8

turbidity, 3-56

turbulent flow, 3-6

unbalanced vane pump, 2-5

unloading valve, 2-26

valves, 1-2, -2 4 actuation, 2-31

cam, 2-31 manual, 2-31 pilot fluid, 2-32 servomechanism, 2-32 solenoid, 2-31 spring, 2-31

design, 2-33 directional-control, 2-28 flow-dividing, 2-24 pressure-control, 2-26

back-pressure, 2-27 hydraulic fuze, 2-28 load-dividing, 2-27 pressure switch, 2-28 regulator, 2-28 relief, 2-26 sequence, 2-27 unloading, 2-26

seating, 2-24 sliding-spool, 2-24 symbols for, 1-6 volume-control, 2-30

vapor pressure, 3-32

viscometers, 3- 6 calibration, 3-8 Cannon-Fenske, 3-7, -8 Cannon-Master, 3- 8 capillary, 3- 6 glass, 3-8 kinematic, 3- 8 Ostwald, 3-8 reverse-flow, 3- 8 Saybolt, 3-7 suspended-level, 3- 8

viscosity, -4 , 3-2

absolute, 3-2 blends, 3-14 definition, 3- 2 Engler 3-3 kinematic, 3-3, -6, -7 non-Newtonian materials, 3- 5 Redwood, 3- 3 Saybolt Furol, 3-3 Saybolt Universal, 3-3, -7 , -9 significance, 1-4

Viscosity Index (V.l.), 3-11, -1 3

Viscosity Index

improvers, 5-1, -6

mode of action, 5- 6 solubility, 5-6 susceptibility to shear, 5- 6 types, 5- 6

viscosity loss, 3-16

viscosity-pressure properties, 3-14

viscosity-shear characteristics, 3-16, -1 8

viscositystability, low temperature, 3-56

viscosity-temperature ASTM charts, 3-9, -1 3 coefficient, 3-11

viscosity, unit conversions, 3-3, -8

-10

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ENGINEERING DESIGN HANDBOOKS Listed elow re he andbooks hich av e een ublished r re urrently nder reparation. andbooks ith ublication

dates rior o ugust 962 ere ublished s 0-series rdnance orps amphlets.

M C ircular 10-38, 9 uly 963,

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