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INDUSTRIAL VOCATIONAL TRAINING REPORT

AMITY SCHOOL OF ENGINEERING AND TECHNOLOGY

AMITY UNIVERSITY RAJASTHAN

JAIPUR(RAJ.)

SESSION 2013-2014

TAKEN AT

HINDUSTAN ZINC LIMITED

UDAIPUR (RAJASTHAN)

DURATION:1st JUNE TO 30th JUNE 2013

SUBMITTED BY:

MONTEK SINGH

B.Tech(M&AE)
http://hzlindia.com/


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INDEX

1. ACKNOWLEDGMENT

2. PREFACE

3. ROASTER AND ACID MAINTAINANCE

4. ACID PLANT

5. LEACHING PLANT

6. CADMIUM PLANT

7. PURIFICATION

8. RESIDUE TREATMENT PLANT

9. ZINC MELTING PLANT

10. ZINC DUST

11. EFFLUENT TREATMENT PLANT(ETP)

12. MECHANICAL MAINTENANCE

13. INSTUMENTATION

14. SAFETY & DRAWING DEPARTMENT

15. ZINC ELECTROLYSIS PLANT

16. COMPRESSOR HOUSE

17. ELECTRICAL MAINTENANCE

18. DIESEL GENERATOR SET(D.G. SET)

19. PROJECT


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ACKNOWLEDGMENT

To accomplish our knowledge, apart from our will Lords blessings wealways need the right guidance and assistance. So here on the verge of

presentation of my technical training report, I thank all those who made

my training a possibility.

I take this opportunity to thanks Mr. P.K. Jain (Senior Manager

HRD, HZL Debari), for giving me this opportunity to work as a trainee

in this prestigious firm. Special thanks to all the staff ofHZL especially

mechanical maintenance department for providing for providing the

wholehearted co-operation and consistent advices.

Last but not the least, I thank everyone whom I came in contact

directly or indirectly for teaching me things I didnt knew before.


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PREFACE

Practical training is a way to implement theoretical to practical use. To

become a successful engineer it is necessary to have a sound practical knowledge

because it is the only way by which one can learn and acquire proficiency and skillto work efficiency at different industries/places. It is a proven fact that bookish

knowledge is not sufficient because the things are not as ideal in practical field as

they should be.

In India a huge amount of public money is invested in government

undertakings. A country like ours, which is based on mixed economy, attaches great

importance to public sector like defense, chemicals, fertilizers, petroleum,

electronics etc. There acceptability to public depends upon the way in which they

manage and control their finance and gives a profitable system on after dischargingtheir social responsibilities and that in terms which depends upon quality of

production of good produced by them and productivity.

It is matter of great pleasure that our college authorities have recommended a

practical training of 30 days to supplement our theoretical knowledge acquire in the

college.

In Hindustan Zinc Limited, Udaipur which is one of the examples to

understand the production process and productivity in particular of zinc.

In this report an attempt has been made to study the overall production

system and related action of zinc smelter, debari a unit of Hindustan Zinc Limited,

Udaipur. That is engaged in production of high-grade zinc metal and other by

product viz. Cadmium, sulphuric acid etc. Since 1968 by adopting hydro

metallurgical technology.

Montek Singh Soni

B.Tech III YEAR

(Mechanical Engg.)


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ROASTER AND ACID MAINTAINANCE

Chief ore used for the extraction of zinc metal is ZnS(Zinc Blend).

This ore is collected from different mines such as Zawar mines, Agucha

mines and is unloaded at the yard.

Typical concentration of blended concentrate is

Zn 53.0

Cd 0.23

Cu 0.11

Ni 0.0057

Co 0.0045

As 0.014

S 31.0

MgO 0.24

Fe 9.0CaO 0.05

Pb 1.7

Sb 0.09

The moistened ore is then led into the roaster furnace through a bet

conveyor. Ore should be moistened properly as per requirement. Since,

zinc in concentrates are roasted to convert sulphide, and hence suitablefor electrolytic production of zinc metal.

There are two roasters at debari zinc smelter. Important details of the

roaster are: -


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I II

TYPE Fluo solid Fluo solid

Supplier M/S lurgi chemic and

hutten tech.

Germany

Capacity(TPD dry) 120 227

Hearth area(m3) 18 35

Hearth dia.(m) 5.65 6.65

Roaster air flow

(m3

/hr)

10000 20600

Roaster bed temp. (oc) 950 920-950

FLUO SOLID ROASTER

In roaster, roasting is based on fluo solid technology where the

material (concentrate) is kept in fluidized state by flowing air through

nozzles in the roaster hearth from the bottom of furnace.

Temperature in roaster is maintained at 900-950oC. Being it is an

exothermic reaction, no external heat is required except initial start up.

For initiating roaster, there are oil burners, which raise the temperature to

350-400oC, and after that temperature up-to 950oC is increased by

exothermic reaction.

Roaster air blower is of centrifugal type having capacity of 25000m3/hr. It supplies the air through the steel duct into wind bose and then

through the nozzles embedded in the ceramic hearth of castable

refractory material. There are 3575 nozzles of 6mm internal diameter.

The furnace cell is provided with:


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Two holes for blend feed at a height of 1800mm from bottom and 2 no.

Of burners holes with capacity of 250 tonnes/hr each. Calcine

production is around is 9.5 tonnes/hr at blend feed rate of 9.5 tonnes/hr.

Calcine obtained after roasting is recovered through overflow and

underflow constitutes nearly 30% of total calcine produced and the rest70% of the calcine is carried away by roaster gases, which passes through

the gas cleaning section.

TABLE SPECIFICATION OF ROASTER: -

NEW OLD

Feed rate of raw

Material

227 T/D 120 T/D

Area of furnace 35 m2 18.5 m2

No. Of nozzles 100 /m2 55 /m2

OTHER INFORMATION: -

Feed machine speed : 70 kphAir flow : 9500 mm3/hr.

Tip opening of the nozzles : 6 mm

Oil pressure of the burner : 10 kgf/cm2

The underflow of the roaster is conveyed by 2 nos. of cooled screw

conveyors of 5 ton/hr. capacity. Calcine from waste heat boiler, at a

temperature of 350oC, is collected into air-cooled redler conveyor of 10

ton/hr. Capacity. The discharge of these conveyors will go through no. 5

redler conveyor. Discharge will also to move to no. 6 redler conveyor.

Remaining calcine will also get collected in no. 6 redler conveyor

installed under hot gas precipitator. Finally, the entire calcine at a


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CONDITION PREVALANT FROM ROASTER TO WET GAS

PRECIPITATOR

Roaster temperature 900-950oC

Water heat boiler: -

Incoming gas temperature 950oC

Outgoing gas temperature 350oC

Pressure in boiler 35-40 kgf/cm3

Cyclones: -



Hot gas precipitator: -



Potential difference across electrodes 7600 V D.C.

Scrubbing tower: -



Single standpipe star cooler: -



Wet gas precipitator: -


Outgoing gas temperature 35-40oC


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ACID PLANT

Roaster gases coming out from the roaster mainly consists of SO2

due to the reaction.

2ZnS + 3O2 2ZnO + 2SO2

This SO2 gas contains nearly 70% of the total calcine produced and

calcine is recovered as discussed in previous article. SO2 gas may cause

cardiac, respiratory diseases, eye irritation etc., so it is not discharge into

the atmosphere but is used for production of sulphuric acid in the acid

plant by DOUBLE CONVERSION DOUBLE ABSORPTION

(D.C.D.A.) method. Sulphuric acid plant has a capacity to produced 200

tonnes of sulphuric acid and has been installed on turnkey basis by M/S

Dharmasi horaji Chemical CO. Mumbai with technical know how from

M/S Lurgie Chemic Und Huttenttchnik, West Germany.

The moisture content in So2 is removed in drying tower.

Temperature of dry SO2 gas is raised to 440oC in a shell and tube type

heat exchanger. With the help of SO2blower, it is led into a convertor

where SO2 get converted into SO3 in the presences of vanadium Penta

Oxide (V2O5) by the following reaction.

2SO2 + O2 2SO3 + HEAT

SO3 gas now absorbed in absorption tower to produce 98%

sulphuric acid.

Convertor is a basically, two-stage convertor. Heated SO2 is a led

into 2-stage convertor consisting of V2O5 crystal as a result of which, SO2

get converted into SO3. This SO3 gas is led into intermediate.

Absorption tower and is absorbed by dilute H2SO4. This result in

the formation of concentrated H2SO4. Gas coming out from Intermediate

Absorption Tower some SO2 which is sent the second stage of convertor

where it is again converted into SO3 and is absorbed in final Absorption

Tower. The acid so produced in nearly 87000TPD. Remaining gases are

then discharged into the atmosphere through a 30 m high chimney.


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LEACHING AND PURIFICATION PLANT

INTRODUCTION

Leaching is a selective dissolution of ore minerals/oxide minerals inacids, alkalis or solution of other reagents according to the condition

adjusted in a manner to leave maximum gangue in the insoluble residue.

Calcine comes in the hopper the help of bucket elevator. From the

hopper the calcine is coming to reddler conveyor through a rotary valve.

By adjusting speed of the rotary valve calcine rate can increased or

decreased. The reddler conveyor is discharging calcine directly into

bazooka. The calcine if in excess is stored in silos.

The average rate of calcine consumption is 11MT/hr, whereas the

rate of solution supplied is 90 m3/hr. This corresponds to 140-150 MT of

zinc ingot per day.

Total calcine storage capacity in the leaching plant: -

Total capacity = 3930MT

Old sios(nos. 1,2,3) = 630MT each

New silos(nos. 4,5,6) = 680MT each

This department consists of following section: -

Neutral leaching

Acid leaching

Purification

Residue treatment plant

Cadmium plant


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NEUTRAL LEACHING

The iron leached from fine particles of ZnO.Fe2O3 will be

precipitated as hydroxide in neutral medium according to the reaction.

Fe2(SO4)3 + 3ZnO + 3H2O2Fe(OH)3 + 3ZnSO4

This ferric hydroxide precipitates and settles in neutral thickener

specially with arsenic, antimony and germanium which are highly

detrimental in electrolysis. Thus with the help of iron these harmful

impurities are removed, so neutral leaching is often called iron

purification.

Total no. Of bazooka = 8

Capacity = 50m3 each

Working capacity = 45m3 each

In neutral leaching, if pH is too low (pH5.0) basic sulphate will be formed

and hence clogging in wet ball mill and the thickener underflow will

take place and undissolved calcine will be left, hence the recovery

efficiency will be affected. Wet ball mill is used to grind unleached

coarser particles separated by spiral classifier. Its capacity is 1MT of

solids per hr. Spiral classifier is semi circular screw conveyor to

seperate coarser solids which settle down.

Dorr thickener a circular sedimentation tank with a centrally

mounted rake with central inlet of slurry and periphery outlet of clearsolution. Thickener is a circular tank with conical bottom provided at

the centre with an inlet well. To accelerate setting of fine particles,

flocculent is added. Settled material is swept from the edges to the

centre by a device consisting of a shaft that carries obliquely fitted

paddle shaped rakes.


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Calcine which is coming from the roaster is leached in continuous

mixing agitator is provided. Temperature of 65-70oC is maintained

throughout in all the bazookas at a pH of 4.5-4.7 to maintain this temp.

steam coil device is provided. Soluble oxide gets dissolved producingrespective sulphate. MnO2 is added to oxidise ferrous to ferric hydroxide

which absorbs some impurities like As, Sb, and Ge and precipitate at 4

pH. The neutral slurry is settled in dorr thickener where floccunt is added

as a settling is, the clear overflow is sent for purification where

underflow is sent to acid leaching.

The Zn in calcine is present as: -

Zno 81-83%

ZnSO4 6-7%

ZnS 1-2%

ZnO.Fe2O3 10%

In the first stage of neutral leaching the solution will be slightly

acidic and hence pH is maintained at 2.8-3.2, so that in neutral

leaching ZnO.Fe2O3 also get leached.

The main reaction is: -

MeO + H2SO4 MeSO4 + H2O

Where, Me=Zn,Cu,Ni,Co,Mg,Ca and Pb

The pH of the solution discharged after completion off leaching is

4.5-4.6 and at that pH, acidity is negligible and the solution is of weak

base and strong acid. Hence it is called neutral leaching.


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Parameters that are maintained in neutral leaching: -

Total iron 2.5-3.0 gpl

Initial pH 2.8-3.2

Final pH 4.5-4.6

Fe++ 5 mgpl

Temperature 65-70oC

Reaction time 150-180 minute

ACID LEACHING

This operated is carried in 6 mild steel, lead and brick lined

bazookas having capacity of 45 m3 at temperature of 80oC . the

underflow from the neutral leaching containing dissolved ZnO and

ZnO.Fe2O3 is leached with spent electrolyte to the pH of 2.8. Alternate

bazookas are provided with heating coils through which steam is passed.Reaction time is 5 hr. Most of the soluble oxidize go into the solution.

The settled in two dorr thickeners with the counter current decantation.

The overflow containing 30-40 gpl of Zn is sent to neutral leaching.

Underflow is pumped to two drum filters (vacuum based).

Acid overflow Acid under flow

Zinc 100-110 gpl Total Zinc 18-20%

Iron 400-500 gpl A/s Zinc 2%

As 4-5 mgpl Solids 300-400 gpl


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CADMIUM PLANT

The first stage purification cake containing Cu, Cd, Co, Ni along with

excess of zinc issent to cadmium plant for recovery of Cd. Excess of zinc

is removed by washing the cake with respect of Cd is also attained

sufficient precaution is taken because hydrogen and toxic gases are

evolved during Zinc dissolution.

Enriched cake is treated with Zinc-spent acid, concentrate sulphuric

acid and cadmium spent acid to dissolved Cd. Air agitation and addition

of MnO2 helps quicker dissolution. Filtered solution is purified from

Antimony etc. by iron purification of controlled pH.

Purification solution is now treated with Zinc dust in order to

precipitate cadmium, which is filtered out. The cake is known as

CADMIUM SPONGE. This is dissolved in exhaust electrolyte of Cd

cells or fresh concentrated H2SO4. After filtration and removal of copper,

solutions electrolyzed in cells to deposit Cd on Aluminium cathode.

Electrolysis is carried at current density of 40 amp/m2 and cell voltage of

2.4-2.6 volts.


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PURIFICATION

INTRODUCTION

Purification of zinc sulphate is necessary as certain element even if

amounting to milligram per litter may cause:

1. Hydrogen evolution and dissolution of zinc by reducing impurities

like Fe++, Co, Ni, As and Sb.

2. Zinc is electropositive to ordinary metals like copper, iron,

cadmium etc. Therefore during electrolysis these elements will tend

to deposit along with zinc, affecting the purity of the final product

and current efficiency.

Parameters maintained in purification

Temperature 82-85oC

Co : Sb 1:.2-.3

Cu in NOF 200 mg/l

Added zinc dust 2.5-3.0 gpl

Principle

The clear overflow from the neutral thickener is fed into the

purification stage. The purpose of this stage is to remove base metal

impurities like Cu, Cd, Ni etc. Which are harmful to the electrolysis of

zinc. All these elements are removed by precipitation with the help ofzinc dust. Zinc being placed higher than all the elements in

electrochemical series of elements, displaces them from solution of

sulphates to zinc sulphate(cementation process) as per the following

reaction:

Zn + MSO4 ZnSO4 + Mppt


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Addition of antimony tartarate and copper sulphate 9if required)

has the rate of reaction to ensure complete removal of impurities, while

Zn-Cu couple is more effective in removal of Ni, the presence of PAT

ensure the availability of free metallic surface of zinc particles foreffective removal of cobalt. Removal of cu & Cd posses a little problem.


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RESIDUE TREATMENT PLANT

The zinc ferrite ZnO.Fe2O3 in the acid thickener underflow gets

leached in the conversion and simultaneously the leached iron is

precipitate as zerosite. Here the reaction is carried out in three stainless

steel/lead/brick lined reactors of 300 m3 capacity each, at a temperature if

95oC to 100oC. Some amount of MnO2 s also added to take care of

reducing impurities. In this operation zinc ferrite is broken into zinc and

iron is precipitated as complex known as zerosite. The main reaction is as

follow:

3ZnO.Fe2O3+12H2SO43Fe2(SO4)3+3ZnSO4+12H2O

The zerosite precipitation is according to the reaction:

3Fe2(SO4)3+(NH4)2SO4+12H2O2(NH4(Fe3(SO4)2(OH)6))+12H2O

The zerosite slurry from these reactions is settled in the dorr with

counter current decantation. Zerosite from the last thickener continuously

pumped to drum filters operating under vacuum, where zerosite cake

separates & filtered again to recover water soluble zinc.

The cake is subsequently repumped & pumped to ETP where it isneutralized to 8pH and discarded into lagoons. The overflow from the

dorr contains 80-100 gpl zinc and 5 gpl iron is send to neutral leaching.


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ZINC MELTING PLANT

Zinc cathodes stacked on wooden ballets are transported from cell

house by an electrically separated forklift struck, weighed and restacked

on to roller table of the Demag or SICO induction melting furnace. The

demag furnace has a holding capacity of 20 tonnes and can melt up to

4 tonnes per hr. This is a main frequency, external channel tilting type

induction furnace. The induction coils, which are air cooled by fans, are

mounted on three side of the furnace around the melting chamber. The

molten metal around the coils flows into the melting chamber into which

cathode packets are continuously charged in a column by a hydraulic

table at the end of the feed roller table the furnace is refractory bricklined and then with a ramming mass. The metal passes below a bridge

into the fore hearth of the furnace from where it is manually bailed out &

cast in a raw of C.I. moulds which are cooled by a water spray can be

tipped on the mould table to disloged the ingots are stacked last of 88

nos. With the bottom raw having legs to facilitate listing by fork lifter.

Each hot weighs around 2 tonnes the molten zinc is passed through three

doors situated by the side of each of the 3 sets of inductor usingammonium chloride flux. The power can be supplied to the three coils in

series or parallel connections by an automatic trip changer which controls

temp. around 480oC depending on the melting rate the main advantage of

this new Demag furnace over the earlier SICE induction furnace is that in

case of a clogging of the channel only the affected chamber can be

changed. Quickly without affecting the main lining as they are external

coils and the furnace can be tilled out. In case of SICE furnace, which is

a stationary type with the chamber and the fore hearth any restriction or

damage necessities a long shut down for the entire relining to redone.


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This furnace also has a disadvantage in that the coils are water

cooled. Where a possibility of clogging always exists, to give rise to over

heating, where as in Demag fue=rnace they are air cooled by fans

mounted on each coil chamber. The melting efficiency runs between 96to 97%

Furnace I Furnace II

Make Demag, Germany Ajax, England

Inductor cooling Air cooling Air cooling

Induction design 3 units, 2 coils 1 unit, 2coils

Holding capacity 30 tonnes 25 tonnes

Melting capacity 4 ton/hr. 4 ton/hr.

Power 400 KW 400 KW

Voltage 440-600 V 100-500 V

Melting efficiency 95.5% 93%


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ZINC DUST

The zinc dust plant is setup with an intention of producing zinc

powder, which is used in Leaching & purification.

In this point, the molten zinc is fed into a metallurgical cake

column, which acts as a resistance where an electric current is passed

through it. This causes zinc to boil and vapours passed into a condenser

system with a recalculating inert gas steam. Zinc dust so formed settled

in condenser tanks and is removed.

There requirement are as follows for a metal capacity of 6 TPD.

1. Raw material 1060 kg of Zn strips on ingots

2. Power 950 KW hr/ton of zinc dust

3. L.D.O. 50 lit/ton of zinc dust

4. N2 gas 1.25 m3/ton of zinc dust

5. Cake 2.6 kg/ton of zinc dust

6. Cooling water 0.274 m3/hr.

PRODUCTS

Zn dust : 94%

Zn dross : 5.5%

Loss : 0.5%

The main sections of Zn dust plant are: -

1. Electrochemical furnace

2. Condenser

3. Cyclone cooler and bag filter


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1. Electrochemical furnace:

Specification:

a) Area : 52 sq. M

b) Cake thickness : 380-400 mm

c) M.O.C. : Heat resistance lined with

insulated refractory bricks

d) Power : 360 KWA

e) Temperature : 450-500oC

The electro-thermal furnace consists of a column of sizedmetallurgical cake contained in a refractory shell, shaft which is

fitted upper & lower graphite electrodes. Ore is situated at the

bottom of column and other near the top. The electrodes enter the

cake column and ore connected to power supply. Zn ingots are fed

into a melting both liquid metals run into a distribution system. The

Zn vapour thus formed passed into a condenser system via a cross

over tube.

2. Condenser:-

Specification:

a) M.O.S. : M.S.

b) Area : 65 m2

The condenser consists of three tanks equipped with copper

bottoms and discharged gates. A recycle system is installed where

by inert gas is mixed with vapour at the point exit from cross over

tube.

Zn dust thus formed falls into copper bottom & discharges

automatically in bins through discharge gates.


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3. Cyclone and bag filter:-

A very fine particle of Zn dust thus passes over from

condenser enters into the cyclone and bag filter. In cyclone the Zn

dust particles settles down and are removed from the bottom.

The Zn dust obtained is of 125-300 mesh size. These are

collected in bags and taken to leaching plant.


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EFFLUENT TREATMENT PLANT (ETP)

Now a days Environment is very important. The effluent coming

out a plant contains a higher level of metal content hence prior to

discharge these effluent metals should be removed. In zinc smelter there

are two major streams:-

(1) Acid circuit: now days dominate part.

(2) Zinc circuit: Not much quantity.

To receive the effluent there are three sumps A01, A02, A03.From

these sumps effluent is taken into reactors of 130m3 capacities. Then

hydrated lime Ca(OH)2 is mixed to maintain the pH 9. All metallic

impurities get settled down in hydroxides form. This slurry goes to dorr

thickener. Overflow of thickeners goes to another reactor where Alumina

ferric is added to control fluoride. Underflow of thickener goes to

zerosite pond.

Composition of zinc stream before treatment

1. Flow : Normal 120 m3/hr.

: Peak 160 m3/hr.

2. pH 1.5-3.5

3. Zinc as Zn 500 to 2000 mg/l

4. Suspended solids 500(max.)mg/l

5. Chlorides 150 to 300 mg/l

6. Iron as Fe 13 to 50 mg/l

7. Cadmium 2 to 5 mg/l

8. Fluorides/Phosphate Traces mg/l


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Quality of treated effluent

pH 8 to 9

Zn 2.0 ppm

Fluorides 1 ppm to 1.5 ppm

Phosphate 5 ppm


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EQUIPMENT/MACHINE MAINTAINANCE PROGRAM

At DZS following maintenance systems are being followed for

machine maintenance as a part of overall up-keeping of plants:-

Preventive maintenance

Shut down maintenance

Opportunity maintenance

Reactive maintenance

Condition based maintenance

CENTER LATHE

Function:-

The main function of centre lathe is to remove metal from a piece

of work to get the required shape & size. This is accomplished by

holding the work rigidly on the machine and then turning a cutting tool

then removes metal from the work in form of chips.

Principle Parts:-

1. Bed

2. Head-stock

3. Tail-stock

4. Carriage

5. Feed mechanism

6. Screw cutting mechanism


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Accessories and attachment:-

They are additional equipment used for specific purpose, are as

follows:-

Lathe Centres

Chucks

Carries

Catch plate

Face plate

Mandrel

Lathe operation:-

Following machining operations can be successively performed on

lathe machine:

1. Cantering 6. Facing

2. Turning 7. Grooving

3. Taper turning 8. Drilling & Boring

4. Chamfering 9. Milling

5. Thread Cutting 10. Grinding

There are five lathes in DZS namely:-

SCVL FORT(FRENCH) LATHE

THE MYSORE KIRLOSKAR LTD.

CELTIC-20 FRANCE

LB/17 M/6 NO. 7815

LB/20 M/6 NO. 2082


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Specification of LB-20 model

Height of centre 200mm

Type of bed GAP & Straight bed

Centre distance 1000mm

Swing over bed 410mm

Swing over cross slide 230mm

Bed width over top surface 312mm

Special accessories Universal face plate chuck

SHAPER MACHINE

Introduction:-

The shaper is a reciprocating type machine tool intended primarily

to produce flat surface. In general, the shaper can produce any surface

composed of straight, line elements. The shaper present in workshop of

DZS is of hydraulic type.

Principle parts:-

1. Base

2. Column

3. Cross Slide

4. Saddle

5. Table

6. Ram

7. Tool head

Specification of shaper


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MADE BY KIRLOSKAR

STROKE LENGTH 0.65 mm

CYCLE/MIN. 50

VOLTS 415 V

CURRENT 15 A

FREQUENCY 50 Hz

H.P. 15 H.P

SPEED 15 rpm

MOTOR 3-PHASE MOTOR

UNIVERSAL MILLING MACHINE

Introduction:-

A milling machine is a machine tool that removes metal as the work

is fed against a rotating point cutter. A universal milling machine is so

named because it may be adopted to a very wide range of millingoperations. The machine can produce spur spiral, bevel gears, twist drill,

milling cutters etc.

Principal parts:-

1. Base 5. Table

2. Column 6. Overhanging arm

3. Knee 7. Front base

4. Saddle 8. Spindle

Milling machine operation:-


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1. Plain & face milling 5. Helical milling

2. Angular milling 6. CAM milling

3. Form & profile 7. Thread milling

4. Gear cutting 8. Saw milling

RADIAL DRILLING MACHINE

Introduction:-

The Drilling machine is one of the most important machines in theworkshop. The radial drilling machine, present in the DZS workshop is

intended drilling for medium to large and heavy work pieces. The

machine consists of a heavy, round vertical column mounted on large

base. The column supports a radial arm which can be raised and lowered

to accommodate work piece of different height. The arm may swing

around to any position over the work bed.

Principle parts:-

1. Base

2. Column

3. Radial arm

4. Drill head

5. Feed mechanism


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Milling machine operation:-

1. Drilling

2. Reaming

3. Boring

4. Trepanning

5. Grinding

6. Tapping

7. Spot facing

8. Counter boring

Drilling machine tools:-

1. Drill

2. Reamer

3. Counter bore

4. Taps

GRINDING MACHINE

Introduction:-

Grinding is a metal cutting operation performed by means of a

rotating abrasive wheel that acts as a cutting tool. This is used to finish

work piece which must show a high surface quality, accuracy of shape

and dimension.

Grinding operation:-


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Principal operation which may be done on grinding machines

include the grinding of external and internal cylindrical grinding, tapered

and formed surface, gear teeth and other using appropriate wheels and

fixtures.

ABRASIVE, is a substance that is used for grinding and polishing

operation. It should be pure and have uniform physical properties of

hardness, toughness and resistance to fracture, to be useful in

manufacturing grinding wheels.

SLOTTING MACHINE

Introduction:-

The slotter operates almost on the same principle as that of the

shaper. The major difference between a shaper and slotter is that in a

slotter the ram holding tool reciprocating in vertical axis whereas in

shaper the ram holding tool reciprocating in horizontal axis. The slotter is

used for cutting grooves, keyways and slot of various shapes, for making

regular and irregular surfaces, for cutting internal and external gears and

many other operations.

Slotting machine parts:-

1. Base 5. Cross slide

2. Rotating table 6. Ram

3. Column 7. Tool head assembly

4. Saddle 8. Feed mechanism

Operations:-

1. Machining flat surfaces


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2. Machining cylindrical surfaces

3. Machining irregular shapes & cam machining

4. Machining slots, keyways & grooves


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Tools:-

1. Vices 9. Vernier calliper

2. Spanners 10.Punches

3. Ring spanner 11. Chisel

4. File 12.Anvil

5. Screw driver 13.Swage block

6. Divider 14.Hammer etc.

7. Pipe wrench

8. Try square


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INSTRUMENTATION

An engineer was to be deprived of his measuring devices; he would be

used to guessing and speculation. Measurement and control is one of the

developing fields in engineering. Recent advances in technology have the

development of most sophisticated instrument, which helps us in openingan eye on what is actually happening at what place so as to ensure the

condition for maximum output. Instrument are used for the following

purpose:

1. To measure level

2. To measure pressure

3. To measure temperature

4. To measure flow

Level measurement:-

Level measurement is made to ascertain the quantity of liquid level

held in the container. Level affects both the pressure and rate of flow in

and out of the container, as such, its measurement and control is an

important function in the processes. The task of liquid level measurementmay be accomplished by employing primary censors such as differential

pressure transmitter, dip tube.

Pressure measurement:-

Measurement of pressure is also needed to maintain safe operating

conditions, to help control a process and to provide test data. The most

common instrument used for the measurement of pressure is bourdonpressure gauge. It contains of an oval sectioned metal tube one end of

which is opened and is led into the vessel whose pressure is required to

be measured. The other end of the tube is closed and is connected

through a crank and lever mechanism to a pointer. This result in elastic

deformation, which is proportional to the pressure. This deformation

causes the pointer to move on a suitably inscribed scale.


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Temperature measurement:-

For measurement of temperature by thermoelectricity, generated

thermocouples are used. The basic principle involved is that When two

conductors of dissimilar metals are joined together to form a loop andtwo unequal temperatures are imposed at the interface connection an

electric current flows through the loop. For convenience of

measurement and standardization, one of the two junctions is usually

maintained at some constant known temperature difference relative to the

reference temperature. Following are the different types of

thermocouples:-

K-type thermocouple (Cr-Al) (0-1200oC)

J-type thermocouple (Fe-tungsten) (0-600oC)

In addition to these, RESISTANCE TEMPERATURE DETECTORS

(RTD) is also employed for temperature measurement. These are usually

made with elements of Platinum, Nickel and copper. Platinum is

preferred because it is physically stable, resists corrosion and chemical

attack, is not readily oxidized and has electrical resistance characteristics.

Leads are taken out of the thermometer for measurement of changes in

resistance in order to determine the value of temperature. The changes in

resistance are usually measured by a Wheatstone bridge.

Flow measurement:-

Flow measurement includes measurement of fluid velocity, flow

rate and flow quantity. For this electromagnetic flow meter, Rota meter,orifice flow meter is used.

An electromagnetic flow meter depends for its operation on

measuring electric current or voltage generated when conducting fluid

flow through an applied magnetic field. From these measurements, the

flow rate may be deduced. Its main advantages include:-


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No obstruction to flow

Can handle slurries, greasy material and liquids containingsuspended matter

High accuracy and reliability

A rotameter consists of tapered metering glass tube, inside which is

located the rotor or active element (float) of meter. The tube is provided

with inlet and outlet connections. The float has specific gravity higher

then that of the fluid to be metered. Spherical slots are cut on the part ofthe float and cause it to rotate slowly about the axis of the tube and keep

it cantered. The float adjusted its position in relation to the discharge

through the passage i.e. the float rides higher or lowers depending on the

flow rate. The discharge is then calculated from the discharge equation of

a meter.


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SAFETY & DRAWING DEPARTMENT

The interruptions in the industry are mainly.

1. Break downs

2. Power failure

3. Industrial relation problem

4. Fires and explosion

5. Accidents

All the interruptions are undesirable but most unwanted is an accident.

The main effects of any accident are.

1. Lowering of production

2. Human suffering

3. Loss/damage of good skilled labourers/employees

4. Material loss

5. Demoralizing effect on employers and society

6. Legit processings harassment to management

7. Comensation

Therefore safety is a must. The meaning of safety is

S Sound thinking concerning the nature of job

A Alertness to danger

F Factorizing the entire operation into safe requirement

E Efficiency in carefully performing the work

T Thoughtfulness to the welfare of group in which the worker is

attached

Y You and your own protection


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When there is a machine it needs the safety of machine and

persons. The company has a safety engineering dept. For this purpose

hazards and accidents may occur any time by a small error of machine

operator or worker. The dept. of safety engineering gives training andguidelines to the workers and other persons time to time. It has put

various boards on and near each dept. in the company. These boards

depict safety majors, in Hindi and in English languages. It also provides

safety equipments i.e. helmet, safety belt, hand gloves etc. This dept.

issue these equipments to workers or other employers.


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ZINC ELECTROLYSIS PLANT

Electrolysis of Zinc Sulphate solution takes place in electrolysis

cells with Aluminium cathodes and Lead anodes as electrodes.

This reaction can be represented as:-

ZnSO4 + H2O + 2e Zn + H2SO4 + 2O2

Zinc ions migrates towards the cathode and get deposited in the

form of a sheet where as oxygen is given off at the anode. As 304 ions

have strong affinity for hydrogen ions this results in formation of

sulphuric acid the oxygen which is liberated oxidizes.

The Manganese Sulphate in solution to Manganese di-oxide which

deposits on the anode. Surface as anode mud, which is cleared out

periodically

Solution cooling & storage:-

Neutral electrolyte from purification shell be available at 60-

70

o

C as hot purification process has been adopted for expansion. Theneutral solution is fed directly to atmospheric coolers of the Hamon

Sobeico design, where solution is cooled to 35oC. Two coolers been

provided for this purpose out of which one would be stand by the cooler

consists of reinforced self supporting FRP panels of 8x8x4 m size.

The Zinc Sulphate solution to be cooled is taken through a main

feeder from which it is distributed through reinforced polyester pipes on

which the stainless steel 316 spraying nozzles are fixed.

Above this drift eliminator are arranged in two layers in the form of

layers of PVC waves assembled in panels are easily removable through

ton of coolers. The cooler is fitted with forced draft fan having FRP

blades, the fan stack is also made from FRP & stainless steel grating

provided protection to fan inlet. Pulleys and belts drive the fan from two


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speed motors. These coolers have been fabricated for the first time in

India with import of a few items.

Circulating spent solution is cooled in separate 5 nos. Coolers out of

which normally three in service & two are stand by here temperaturedrops from 42 to 35oC. Due to Gypsum deposit which takes place in

these coolers. Periodically cleaning are done in about 4-5 days.

Cell house:-

Electrolysis takes place in lead lined concrete cells which are

connected electrically by means of copper bus bars in a series & parallel

system for flow of current. In the existing cell house there are 240 cellsarranged. These cells are arranged in 40 rows. Each one has six cells

arranged in cascade. Each cell is provided with 27 Aluminium cathodes

& 28 head anodes. After expansion each cell will have its own feed

system and its own independent discharge of electrolyte. Accordingly

modifications are being carried out in the existing cell house. In the new

cell house 320 cells have been provided, arranged in 40 rows of 8 cell

each. New cells are flat bottom provided with 30 Aluminium cathodes

and 31 ardentiferous lead anodes. PVC anode spacers have been provided

for the voltage between electrodes shall be 3.45 volts & current density

of 400-450 amp 2 shall be maintained. The whole cell house has been

divided into three circuits are regards feeding and reactivation of

electrolyte.

1. In the I circuit feed will be a mixture of spent electrolyte and

neutral solution in the ratio of 7:1 Zinc cathode production fromthis circuit would be about 123 MT per day. Spent electrolyte from

this circuit will be cooled by atmospheric coolers and recirculated.

Total no. Cell in this circuit will be 428.

2. In the II circuit there will be 108 cells for which feed will be cooled

spent electrolyte from above Zinc production from this circuit


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containing 50 gpl Zinc and 143 gpl H2SO4 shell present to leaching

& purification without cooling.

3. Feed will be coiled spent electrolyte from first circuit in the column

circuit. Total no. Of cells in this circuit will be 24 known as bleed

cells.

These cells would be arranged in true cascade(and cooled by coils) to

get the bleeding liquors containing 10 gpl Zinc & 180 gpl H2SO4. The

cascade system allows maximum Zinc recovery from the solution.

Volume of the solution to be purged depends on magnesium balance of

the system. Production of Zinc forms this circuit would be about 4.9

tonnes per day.

The deposit Zinc is stripped from the Aluminium cathodes in 1-2 mm

thick sheets every 24 hours and sent to melting furnace 10 nos. Cathodes

are removed at a time from cell and sent to stripping platform. Remaining

20 nos. In the cell ensure the passage of current during standard

exchange. The cell cleaning shall be done by vacuum cleaning device.

Total cathode production from existing as well as new cell house will be

147 tonnes per day with 93% over all recovery efficiency from zinc

present in calcine fed to leaching plant & Zinc recovered in the form of

Zinc cathode. Energy consumptions would be 3330 KWH per tonne of

cathodes measured on D.C side 1873 m3 of electrolyte section per day.

Out of which 1490 m3 of spent electrolyte with 50 gpl Zinc and 143 gpl

H2SO4 will be sent back to leaching & purification section every day

about 80 MT of solution with 10 gpl Zinc will be purged out.


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COMPRESSOR HOUSE

Zinc Smelter, Debari has a central compressor house for supplying

compressed air through out of the plant. The compressor house produces

two types of air.

1. Process air

2. Instrument air

Process air is used in process work such as conveying, cleaning,

hoisting etc. where as the instrument air is used in different types of

instruments such as recorders, control valves etc.

The compressor house consists of the following compressor:-

S.

No.

Make & Model Capacity

m3/min

Working

pressure

Kgf/cm2

Motor

power

KW

RPM Nos.

PROCESS AIR

1. Kirloskar TSTB 15.4 7 90 1470 2

2. CPT Consolidated

14x13

15.4 7 93 1460 2

3. K.G. Khosla

2HA4TER

29.75 8.4 185 (1)735

(2)1480

2


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INSTRUMENT AIR

4. KirloskarTC100M 2.69 7.5 22 1460 3

5. Ingersoll-Rand 7x5

ESVINB2

2 7.5 22 1440 3

6. Ingersoll-Rand

5x3x3.5

0.7 7.5 4.4 1435 1

7. Ingersoll-Rand

029TAx3

83.2 47.97 515 2975 1


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ELECTRICAL MAINTENANCE

For the establishment and proper run of any factory, these are two

basic requirements to be considered:-

1. Electricity

2. Water

Here HZL, the incoming supply from RSEB is 132KV, which is step

down, by 2 nos. 30 MVA, 132/11 KV transformers, 11 KV supply is

received in main control rooms which is distributed to all substations in

different plant location.

At substation, again 11 Kv is step down to 415V and then 415V fed to

various type of plant and so on.

In case of power cut from RSEB or any further emergency there are

facilities of diesel generator sets, which can be operated to give the

continuous supply of power to the plants, so that there may no

interruption in the work or production.

The other important requirements are water, which is supplied from

the lakes of Udaipur without any interruption.


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DIESEL GENERATOR SET (D.G. SET)

Diesel plants are more efficient. These plants are cheap in the initial

cost, can be started & stopped quickly & can burn a wide range of fuels.

It does not require any warning period. It need not be kept running for a

long time before picking up load. As a result there are not staidly losses& also it does not need large amount of water for cooling.

Description:-

A diesel engine is four stroke engine. The fuel injected directly at

high pressure & high temperature air in the engine cylinder. Mixing of

fuel takes place inside cylinder & a heterogeneous mixture is formed.

Ignition of mixture is achieved, owing to high gas temperature.

Following are the main characteristics features of the diesel

engine:-

Cylindrical arrangement:-

V-engines:- These engines contain two banks of cylinder attached

to same crankcase using same crankshaft.

Cooling system:-

Water-cooled engine:- In these engine the cylinder walls & cylinder

head is cooled by water.

Essential systems which runs the D.G sets:-

1. Engine starting

2. Engine exhaust gas system

3. Engine cooling system

4. Engine lubrication system

5. Engine air intake system

6. Engine fuel system


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Two sets are in working order: Allen1 & Allen 2. As indicated above

we can describe all the system of D.G. sets.

1. Engine Starting :-

All the D.G sets have compressed air starting. The circuit of starting as

follows:-

Fresh air Air compressor Solenoid valve

Injector Cylinder head Distributor

Feed pump Auto filter Flow meter

Fuel tank Filter

At the time when the required rpm is net then fuel injector is

started. It include silencer, connecting ducts(turbocharger). As the

temperature of the exhaust gases is sufficiently high, heat of these gases

is utilized in heating oils or air supplied to engine.

2. Engine exhaust system :-

For purpose of cooling of engine cylinder, the cooling water is passed

through jackets. The water is used for cooling engine cylinder is soften

by water treatment or water filtrations in order to avoid scale formation

in it.

3. Engine lubrication system :-

In this lubrication oil is drawn by means of a pump & is passed

through a strainer & filter. Usually the lubricating oil is drawn from thepump & if it is not, it should be heated to increase its velocity & the

filtration easy. The oil is then cooled through a heat exchanger to engine.


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Fuel:-

For engine heavy or light fuel are used according to required. It is

good to maintain temperature nearly 110oC in flow of fuel. To increase

the temperature a heating coil is used in overflow pipe which is

completely insulated.

Starting on light fuel:-

1. Put the motor driven lubrication oil priming pump on auto control.

2. Set the over speed in the RUN position. Put the fuel cut out leverin the RUN position. Open all valves in the fuel supply system.

3. Open the main valve on the starting air supply.

4. Leave all the valves in the water supply system open.

5. Put the governor speed adjusting control knob in the normal

running position.

6. Leave all valves in the injector temperature control system open

and switch on the coolant header.

7. Start the engine from remote.

8. Let the engine run on low speed for few minute and then rise to

normal speed.

In operation:-1. Check the lubrication oil and cooling water pressure.

2. Drain the compressor and turbine outlet of the turbocharger once in

8hr., water wash compressor once in 24 hr. And turbocharger once

in week or 200 hr.


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Stopping:-

1. Run the engine on light load for a few minute before stopping to

allow it to cool.

2. Initiate stop sequence at the control panel.

3. Put the fuel pump cut out lever in the STOP position and close

the fuel oil supply valve.

4. Switch of the injector door should not be opened until the engine is

cooled.

Operating on heavy fuel:-

Start the engine on light fuel as per instruction.

Change over to heavy fuel:-

1. Raise the temperature of heavy fuel to 160 pc in the engines bus

rail.

2. Ensure that all the valves are correctly set on the engine fuel oil

module and that the air supply is available.

3. Select Heavy at the engine control panel. Check for the jacket

water outlet temperature which should be above 75oC before

selecting Heavy the fuel system will automatically change over to

heavy fuel.

4. Ensure that the pressure regulating valves are set at 3 kg/cm2 at

engine bus rail. If the engine misfires due to vaporization of light

fraction increases. The pressure slightly increases by adjusting theregulating valves.


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Stopping on light fuel after running on heavy fuel:-

1. Select distillate at the control panel. The valve on the engine fuel

oil module will change over automatically and purse sequence will

be completed.

2. Run the engine for at least 10 min. On the full load to flush the

engine c/r. If running on reduced load, the time must be

correspondingly increased.

3. Continuous detailed in stopping light fuel.


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Rating of diesel engine of D.G. sets:-

Make Allen

Type 4-stroke,16 cylinders

Compression ratio 12:1

Starting ratio Compressed air (20 kg/cm2)

Lubricating oil Servo marine

Speed 750 rpm

Temperature of supercharger 450oC

Exhaust temperature 450oC

Inlet temperature 45-55oC

Engine cooling DM water

Jacket coolant pressure 12bar

Secondary coolant pressure 2.6 bar

Lubricating oil main pressure 2.5 bar

Capacity 5 MW


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PROJECT REPORT

DESCRIPTION AND BASIC FEATURES

Name :- Fully Automatic signode Strapping Machine

Model :- M410-N-34-CH12i

The fully automatic signode strapping machine M410-N-34-CH12i is

designed suitably to apply the steel strap on circumference or to the surface of the

stack of zinc ingots.

Specification:-

Made or installed: - Made in JAPAN,2004

Cost: - 1 crore 30 lakhs(approx).

No. Of straps used: -4

Straps coils upto max: - 250 kg

Stroke: - 1400 mm.

Speed: - 6min 30sec for 1 lot to pack.

Weighing: - By load cell.

Cost of one roll of strap belt: - Rs. 6000(change after 24 hrs.)

Packing cost: - 1 lot Rs. 40

ITW (Ionized tool works) is running or operating the machine on contract basis.

Connections:-

1. Electrical Connections:-

Main power: - 415 V 3 phase 50 Hz.

Input voltage: - 24 V DC

Output voltage: - 110 V AC

2. Pneumatic connections: -

Air Pressure: - 5.5 bar(min)


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Lubrication: - online lubrication.

Air quality: - compressed dry air.

Air consumption: - 95 ltr/m free air.


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BASIC TERMS

1. Package: - The product on stack of products being strapped.

2. Head: - Also psm for former strapping machine the unit that feeds takes

up tension, notches and cut off the straps.

a. Application machine: - The machine into which head is mounted.

b. Take up: - The process of pulling the strap out of the chute and around the

package.

c. Tension: - The process of drawing the strap tightly around the package.

d. Sealing or notching: - The process of forming notches in the strap seal to

complete the joint.

3. Pre-feed or feed: - The process of pulling strap into the head and drawing

it through the strap chute around the package and break to the head. In

most of the application strap is partially in chute when the strap cycle

begins. Because the cycle concludes with feeding of strap into the chute

again.

Major Components

1. Air motor : - The air motor powers the transmission and strap tension is

controlled by regulating air pressure to the air motor for specific

adjustment instructions refer manual for air pressure level.

Warning: - For proper operation air supply to the air motor must be set to

deliver a minimum of 70 pslg and a maximum of 90 pslg. However

between low speeds, air pressure to the air motor must not exceed 70

pslg.


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2. Transmission : - The transmission drives through traction wheel. Feed

occurs when the transmission shaft runs in the forward direction. Take-up

and tension occurs when the transmission output shaft runs in reverse

direction. The traction wheel is turned at high speed for feed and take-up.

During tension, the transmission shift in the low speed.


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3. Traction wheel : - The traction wheel is driven by the transmission and

contracts the strap directly. It performs 3 functions of the strapping cycle

feed, take-up and tension.

4. Air cylinders : - The n410-n-34 head has 3 external cylinders, one to

control the gate another to eject the seals. A two in one cylinder for

gripping, notching and cutting the strap.

a. Gate cylinder : - Mounted behind the gate. During strap feed phase, it

holds the gate closed to the air. The strap within the job area. Just prior to

take-up and tension. The cylinder extends to open the gate.

b. Seal eject cylinders : - It is mounted on the right side of the seal magazine,

ejects seal into the jaw stack.

c. 2 in 1 cylinders, small : - The small cylinder mounted within the larger

cylinder advances the jaws to grip and hold the lead end of the strap.

d. 2 in 1 cylinder, large : - The large cylinder move like jaws to notch the

overlap strap, seal the strap and cut off the supply of strap.

5. Jaw stack : - The jaw stack is composed of the moving and stationary

cutter for cutting grip jaws, for securely holding this lead and of the strap

and the notches for sealing.


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6. Strap straightner : - It removes natural curl in the strap that it left it would

adversely affect strap feed reliability.


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PRINCIPAL OF OPERATION

1. Take-up cycle : -

A. Air is sent to the cap end of the gate cylinder and the rod, and is evacuated

at a metered flow rate. The gate cylinder extends, opening the gate away

from the jaw stack area for final strap cycle phases.

B. Then the air motor reverses and airflows unmetered, turning the traction

wheels in the tension direction at high speed, drawing strap out of chute

gates and around the packages. Excess strap passes back through the strapstraightner.

C. After taking up strap at high speed for a predetermined interval of time,

airflow to the air motor is metered down to complete the take of strap at a

reduced rate of speed.

2. Grip cycle : -

A. Air is evacuated from the rod end of the large 2 in 1 cylinder.

B. The constantly pressured cap end of the small 2 in 1 cylinder partially

advances the piston rod, moving the jaws into the grip position and

impinging the central proximity switch. Grip jaws hold the outer strap

against the grip side of the stationary cutter.

C. The valve that controls the gate cylinder extension receives the control

signal.


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SAFETY INTRUCTIONS

1. Bearings to be checked for free movement.

2. Check the amperage of motor.

3. Apply grease in the guides

General safety instructions: -

1. Straps shouldnt be handled without hand gloves and eye protection.

2. Safety shoe are recommended for person involved in handling the cord of

strap.

3. Immediate work area of equipment should be kept clean of any debris, oil or

any other material likely to create hazard.


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a. Dirt accumulated on photo sensor and proxy switches must be cleaned.

b. Filter must be emptied for water.

c. Dust on jaw stack to be removed by using air spray.

d. Check air pressure.

2. Weekly : -

a. Loose screw must be tightened.

b. Check and tighten the air supply points .

c. Check cylinder mountings.

d. Maintain strapping head.

e. Check gates and align if required.

3. Monthly :-

a. Always beware of fact that fully automatic machinery with moving parts may

move at any time without warning.

b. Never assume machine to be safe because of lack of movement. Isolate

power supply at all times before carrying out any work. Also if machine is

not to be used for any extended period.

TROUBLE SHOOTING


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While locating the causes for the following symptoms on M410-N-34-CH12i head,

keep electrical and pneumatic systems on.

1. Symptom(sym) : - Air motor fails to start or run slow

Causes: -

a. Insufficient air pressure.

b. Wear or damage to air motor vanes.

c. Seizure of air motor caused bogy insufficient lubrication or invasion of

foreifn particles.

d. Seizure or damage to the transmission.

Remedy: -

a. Check pneumatic circuit.

b. Replace air motor.

c. Replace air motor vanes.

d. Replace the transmission.

2. Sym : - Transmission fails to shift

Causes: -

a. Insufficient pilot air pressure.

b. Wear or damage of o-ring clutch plate.

c. Wear or damage to the meshing gear of clutch piston and carrier plate.

Remedy: -

a. Check pneumatic supply.

b. Replace the o-ring.

c. Replace clutch piston on the carrier plate.

3. Sym : - Temperature of air motor rises


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Causes: - Insufficient lubrication.

Remedy: - Check lubrication adjustments.

4. Sym : - Temperature of transmission rises.

Causes: -

a. Amount of grease is too little or too much.

b. Excessive wear of gear teeth or bearing.

Remedy: -

a. Check for proper amount of grease.

b. Replace worm gears on bearings.

5. Sym : - Traction wheel rotates in the feed direction but not feed strap.

Causes: -

a. No strap in head.

b. Insufficient energizing of strap.

c. Seals mechanism not fully retracted, blocking strap path.

Remedy: -

a. Rethread the strapping head.

b. Tighten spring extension screw.

c. Remove any obstruction in the sealer jaw inspect the jaw.

6. Sym : - Incomplete or improper feed.

Causes: -


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a. Excessive curl in strap.

b. Slow running motor.

c. Worn traction wheel.

Remedy: -

a. Adjust strap straightened. Natural curl must face away from the front of

the head.

b. See failed or slow running air motor sym.

c. Replace traction wheel

7. Sym : - Head fails to go into the grip phase of the strapping cycle.

Causes: -

a. Incomplete strap feed.

b. Rod end of large cylinder fails to exhaust.

Remedy: -

a. Checking for sticking value or electrical malfunction.

b. See incomplete or improper strap feed sym.

8. Sym : - Strap unthreads from the head during take up or tensioning.

Causes: - Worn or damaged grip jaws or stationary cutter.


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Remedy: -Replace the jaws or stationary cutter.

9. Sym : - Insufficient strap tension.

Causes: -

a. Air motor running slow.

b. Air pressure too low.

Remedy: - Adjust air pressure. Sym: - Strap breaks at grip jaws during

tensioning.

Causes: - Gripping edges of jaws and/or stationary cutter too sharp.

Remedy: - Lightly stone the sharp edges of jaws/cutter.

10.Sym : - Traction wheel mills the strap.

Cause: -

a. Tension is set too high.

b. Worn traction wheel.

c. Final take up speed too high.

Remedy: -

a. Reduce air pressure.

b. Replace the traction wheel.

FREQUENTLY OCCURING BREAKDOWNS

1. Breakdown in jaw stack assembly : - The main part of the machine which is

prone to frequent breakdown is jaw stack assembly. Inside it a pin is used


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which is frequent to break. This pin is an essential part of strapping. It is used

for proper sealing.

Another part of jaw stack causing problem is nozzle jaw. This is used for

cutting. Dust gets accumulated over it. Using air spray can do this.

2. Breakdown due to photo sensors : - Photo sensor are used for the proper

displacement, alignment, positioning and dispatching, weighing, stopping,

bypassing purpose for a lot. Some times dust get accumulated over it due to

which some errors are created.

Photo sensors are the devices, which work on the principle that whenever

light is incident over it than some electric current is produced in it.

3. Breakdown due to hydraulic table : - Work of hydraulic table is to rotate andbring the lot to correct position under strapping head and to turns it face for

strapping. But sometimes table does not rotate properly, therefore it is not

aligned to strapping head, thus causes problem during packing hence causing

breakdown.

To remove the fault it is again set manually by a hydraulic machine through

control panel.

4. Breakdown due to conveyor chain : - Conveyor chains are used to transport

the lot of zinc ingot from casting to packing machine and then to the

strapping head, to the weighing and then to dispatching. Sometimes these

chains get trip off which causes the breakdown.

Breakdown due to strap gates: - Strap gates sometimes gets misaligned so it

becomes difficult for proper strapping of lot. So it should be aligned properly.

project mech

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