4b condensed qa

7/24/2019 4B Condensed QA

1/160

.7.3 Testbank.Document.Questions Page 1 for Testbank PE4PARTB 25!EP2""1

T#e s$mbo%s be%o& are use' as in'icate'() a'' * mu%ti+%$ subtract , 'i-i'esr suare root // e*+onent// e*+onent

0TE(Roun' off to 3 'ecima% +%aces un%ess ot#er&ise state'.R

Heat Engines, Prime Movers & The Simple Steam Engine

"1"1"""2""21"""BA +rime mo-er is

b a steam turbine

"1"1"""2""21"""6arge +o&er +ro'uction +%ants ten' to be of t#e t#erma% t$+ebecause t#e$ can burn so%i' fue%s an'(

c t#e #eat c$c%e t#e$ use is t#e most efficient

"1"1"""2""21"""AA steam engine &i%% #a-e t#e steam su++%$ to t#e c$%in'ers#ut off once t#e +iston #as tra-e%%e'

a 25 to 35 or 1,4 to 1,3 of its stroke

"1"1"""2""21"""DT#e reci+rocating motion of a steam engine is con-erte' torotar$ motion

' at t#e cranks#aft

"1"1"""2""21"""BT#e cross#ea' of a steam engine

b is ere %inear motion becomes angu%ar motion

"1"1"""2""21"""D

A steam engine +iston

' mo-es fastest at t#e beginning of its stroke

"1"1"""2""21"""AA routine ins+ection of an o+erating steam engine s#ou%'co-er first an' foremost

a %ubricators

1


2/160

"1"1"""2""21"""8#ene-er feasib%$ +ossib%e9 en c#ecking bearings on running+ieces of eui+ment it is &ise to

c get accustome' to norma% running tem+erature

an' -ibration b$ fee%

"1"1"""2""21"""Ane of t#e first &a$s to 'etect a fau%t in a reci+rocatingengine is

a b$ soun'

"1"1"""2""21"""DT#e slide valveof a steam engine is 'esigne' to

' +ro-i'e for t#e steam to enter an' %ea-e t#ec$%in'er

Steam Turbines I

"1"1"""2""21"""DA steam turbine:s e*#aust can often su++%$ a +rocess &it#steam because

' it is free of oi%

"1"1"""2""21"""T#e e*#aust steam from a steam turbine is more acce+tab%e for+rocess t#an t#e e*#aust from a steam engine because

c it is free of oi%

"1"1"""2""21"""ET#e e*#aust steam from a con'ensing steam turbinehas more moisturet#an t#e e*#aust from a steam engine(

e) has more moisture

"1"1"""2""21"""DTurbines often #a-e segmenta% carbon ring sea%ing g%an'sic# are #e%' in +%ace b$ garter springs

' garter s+rings

"1"1"""2""21"""DA steam turbine s#ou%' tri+ or s#ut 'o&n en norma%

2


3/160

o+erating s+ee' is e*cee'e' b$ 10 to 15%

"1"1"""2""21"""Bon'ensing turbines

b) will have a vacuum in the last row of rotatingblades

"1"1"""2""21"""B8#ic# turbine uses a con'enser;

b) a turbine exhausting to a vacuum

"1"1"""2""21"""ET#e s#rou'ing insta%%e' on t#e b%a'ing of a steam turbine ser-esto(

e) confine the steam to the blades

"1"1"""2""21"""AT#e turbine o-ers+ee' tri+(

2. +re-ents t#e turbine e*cee'ing t#e ma*imum rate' s+ee' 4. &i%% c%ose t#e steam sto+ -a%-e 5. s#ou%' be teste' before t#e turbine is +%ace' in ser-ice

"1"1"""2""21"""BT#e o-ers+ee' tri+ of a steam turbine

b is insta%%e' on a%% turbines

"1"1"""2""21"""BTurbine o-ers+ee' tri+

b &i%% c%ose t#e steam sto+ -a%-e to t#e turbine

"1"1"""2""21"""DTurbine %ubricating oi%

' can be use' to o+erate t#e turbine go-ernor

"1"1"""2""21"""T#e +ur+ose of turbine g%an's is to +re-ent

c steam esca+ing from t#e turbine

"1"1"""2""21"""E!#aft sea%ing in high output turbinesis 'one &it#

e %ab$rint# sea%s

3


4/160

"1"1"""2""21"""B8#en t#e steam +ressure 'ro+ occurs in on%$ t#e stationar$members or com+onents of a turbine9 t#e turbine is kno&n as an im+u%se unit

b an im+u%se unit

"1"1"""2""21"""EA %arge reaction turbine &i%% #a-e steam pressure droppingt#roug# BT< mo-ingan' stationar$ sections Reaction = steam +ressure 'ro+s o-er BT &it# a 'e-ice ic# &i%% be%imite' to about 1" o-er t#e rate' s+ee'. T#is 'e-ice ist#e

' #an' s+ee' contro%

"1"1"""2""21"""Turbine t#rust bearings are fi*e' to t#e casing an' +re-enta*ia% mo-ement of t#e s+in'%e b$ contacting a com+onent ont#e s#aft kno&n as a

c co%%ar

"1"1"""2""21"""D!#aft sea%ing carbon g%an's are

' se%f%ubricating

"1"1"""2""21"""T#e great ma?orit$ of steam turbine go-erning s$stems uti%i@et#e

c mec#anica% centrifuga% +rinci+%e

"1"1"""2""21"""BReaction turbines

b #a-e a +ressure 'ro+ t#roug# t#e mo-ing an'stationar$ b%a'es

"1"1"""2""21"""BReaction turbines

b #a-e a -e%ocit$ increase in t#e fi*e' b%a'ing

"1"1"""2""21"""Bn an im+u%se turbine

4


5/160

b t#e steam +ressure is re'uce' in t#e no@@%es

"1"1"""2""21"""ET#e steam turbine t#at #as a +ressure 'ro+ acrosse-er$ set of b%a'es is t#e reaction turbine.

e reaction

"1"1"""2""21"""D8#en starting a steam turbine it is customar$ +ractice to

' test t#e o-ers+ee' tri+ as soon as runnings+ee' is attaine'

Cooling Towers

"1"1"""2""21"""D

T#e a-erage amount of &ater -o%ume ic# e-a+orates from acoo%ing to&er is 5

"1"1"""2""21"""A0atura% 'raft coo%ing to&ers o+erate most effecti-e%$ in%arge o+en s+aces an'

a ere &in' is re%ati-e%$ constant

"1"1"""2""21"""BE*cessi-e &in' -e%ocit$ in a natura% 'raft coo%ing to&er ma$cause

a %ou-ers to become broken

b #ig# &ater 'rift or %osses

"1"1"""2""21"""om+are' to a crossf%o& to&er9 a counterf%o& to&er

c reuires %ess f%oor s+ace

"1"1"""2""21"""E8ater containe' in t#e airstream at t#e 'isc#arge of acoo%ing to&er is remo-e'

e &it# 'rift e%iminators

"1"1"""2""21"""A coo%ing to&er ic# reuires neit#er fan nor fi%% is t#e

c -enturi unit

"1"1"""2""21"""E

5


6/160

A -a%-e ic# +re-ents &ater f%o& o-er t#e fi%% of a to&er'uring co%' &eat#er s#ou%' not be c%ose' unti% t#etem+erature reac#es 27e ) 27 'egrees

"1"1"""2""21"""BTo +re-ent coo%ing to&er basin &ater from free@ing 'uringco%' &eat#er man$ units are eui++e' &it#

b e%ectric basin #eaters

"1"1"""2""21"""Dou are re+%acing t#e coo%ing to&er fan motor bearingsbecause

' t#e rotor &as rubbing t#e stator

"1"1"""2""21"""D

!ca%ing is not as se-ere in to&ers en com+are' to boi%ersbecause

' tem+eratures are not as #ig#

Gas Turbines I

"1"1"""2""21"""A gas turbine com+ressor is usua%%$

c '$namic a*ia% 'esign

"1"1"""2""21"""AT#e com+ressor on t#e gas turbine

a can be 'ri-en b$ t#e %oa' turbine

"1"1"""2""21"""T#e combustion c#amber of a gas turbine

c burns fue% &it# e*cess air

"1"1"""2""21"""Dan$ t$+ica% steam +%ant au*i%iaries are e%iminate' &it# agas turbine 'ue to its

' sim+%icit$

"1"1"""2""21"""BCas turbines are -er$ +o+u%ar ere

6


7/160

b &ater is scarce

"1"1"""2""21"""BCas turbines are i'ea% en consi'ering

b emergenc$ +o&er generation

"1"1"""2""21"""AA t&o s#aft gas turbine

a #as t#e %oa' turbine 'o&nstream from t#ecom+ressor turbine

"1"1"""2""21"""A gas turbine is not se%fstarting. t must be rotate' at2" to 2" of its ma*imum s+ee' before fue% is turne' on.

c 2" to 3"

"1"1"""2""21"""Ear%$ gas turbines &ere #an'ica++e' b$

c meta%s not stan'ing t#e #ig# tem+eraturesin-o%-e'

"1"1"""2""21"""DT#e tem+erature to ic# t#e air can be raise' at t#e turbine

in%et is

' an in'ication of t#e unit:s efficienc$

"1"1"""2""21"""AT#e out+ut +o&er of a gas turbine is 'irect%$ re%ate' to t#e

a mass of gas +assing t#roug# t#e turbine +ersecon'

"1"1"""2""21"""ET#e %o& insta%%ation cost of a gas turbine is

e because %ess au*i%iar$ eui+ment is nee'e'

"1"1"""2""21"""!ome of t#e c#aracteristics ic# make t#e gas turbine a betterc#oice o-er ot#er +rime mo-ers are(

1. %o& maintenance 2. minimum coo%ing &ater

7


8/160

4. ra+i' startu+ an' %oa'ing

"1"1"""2""21"""ET#e air si'e of a gas turbine regeneratoris %ocate'

e 'o&nstream of t#e com+ressor

"1"1"""2""21"""DA gas turbine +erforms most effecti-e%$ if

' ambient air tem+erature is %o&

"1"1"""2""21"""BA combine' steam an' gas turbine arrangement can be terme'

b a cogeneration s$stem

"1"1"""2""21"""BT#e +ur+ose of a regeneratoris

b to im+ro-e t#e efficienc$ of t#e turbine

Internal Combustion Engines I

"1"1"""2""21"""Bn a com+ression ignition engine t#e fue% is ignite' b$

b t#e com+resse' air tem+erature

"1"1"""2""21"""Diese% engine go-erning is accom+%is#e' b$

c -ar$ing t#e fue% uantit$

"1"1"""2""21"""T#e fue% for a 'iese% engine is

c mec#anica%%$ atomi@e' b$ #ig# +ressure

"1"1"""2""21"""Aourstroke c$c%e engine -a%-es are

a o+erate' b$ cams

"1"1"""2""21"""An engine ic# 'e-e%o+s one +o&er stroke &it# e-er$ ot#erturn of t#e cranks#aft is t#e

8


9/160

c four stroke natura% gas engine

"1"1"""2""21"""Aour c$c%e engine %ubrication is usua%%$

a force' b$ +um+"1"1"""2""21"""An e*am+%e of an engine ic# gi-es #ig# torue at %o& s+ee's&ou%' be t#at of a

c four stroke motocross motorc$c%e

"1"1"""2""21"""DA t&o c$c%e engine

' >+o+s> t&ice as often as an eui-a%ent

c$%in'er four stroke engine"1"1"""2""21"""APremi*ing %ube oi% an' fue% or #a-ing a s+ecia% %ube oi%in?ection s$stem is t$+ica% of t#e a-erage

a sno&mobi%e engine

"1"1"""2""21"""EA ma?or 'ifficu%t$ encountere' &it# a two-strokec$c%e engineis

e e*#austing t#e s+ent gases from t#e c$%in'er"1"1"""2""21"""E

e is of more sim+%e construction t#an a fourc$c%e

"1"1"""2""21"""$%in'er sca-enging

c is t#e remo-a% of e*#aust gases from t#ec$%in'er

"1"1"""2""21"""AT#e +ur+ose of a s+ark +%ug is

a to ignite t#e fue% air mi*ture in a gaso%ineengine

"1"1"""2""21"""B

9


10/160

om+ression ignition engines

b &i%% com+ress air on%$ on t#e com+ressionstroke

"1"1"""2""21"""ET#e in?ection +um+ of a 'iese% engine is 'ri-en b$

e t#e cams#aft

"1"1"""2""21"""Dgnition in a 'iese% engine is starte' b$

' com+ression in t#e c$%in'er

"1"1"""2""21"""Asing a com+resse' air starting motor is a +o+u%ar met#o' ofstarting a

a %arge stationar$ 'iese% engine

"1"1"""2""21"""D8#en using com+resse' air to eac# c$%in'er for starting+ur+oses9 t#e +ressure is a++ro*imate%$ 21""kPa

' 291"" kPa

"1"1"""2""21"""Re'uction in sea%ing ua%ities bet&een t#e +iston rings an'

c$%in'er &a%% b$ t#e %ube oi% ma$ be t#e resu%t of

c #ig# coo%ing &ater tem+erature

Types of Pumps

"1"1"""2""21"""EA +um+ is ca+ab%e of suction %ift 'ue to

e atmos+#eric +ressure

"1"1"""2""21"""entrifuga% +um+s 'o not 'e-e%o+ goo' suction %ift because

c t#eir interna% com+onent c%earances are too #ig#

"1"1"""2""21"""At is genera%%$ accurate to sa$ t#at

a .F kPa +ressure resu%ts from e-er$ metre of &ater 'e+t# or #eig#t

10


11/160

"1"1"""2""21"""EPreferab%$9 '$namic +um+s s#ou%' be %ocate'

e be%o& t#e %iui' source en suction #ea' is in-o%-e'

"1"1"""2""21"""ET#e -ertica% 'istance from t#e %iui' surface u+ to t#e +um+centre%ine +%us t#e -ertica% 'istance from t#e +um+centre%ine u+ to t#e surface of t#e %iui' in t#e 'isc#argetank is

e tota% static #ea'

"1"1"""2""21"""AT#e 'ifference bet&een static suction #ea' an' static'isc#arge #ea' is

a tota% static #ea'

"1"1"""2""21"""B8#en a +um+ 'isc#arges into a -esse% o+erating at 3"" kPa9t#e 3"" kPa is referre' to as

b eui-a%ent #ea'

"1"1"""2""21"""BT#e tota% static #ea' of a +um+

b is t#e 'ifference bet&een t#e static suction #ea' an' t#e static 'isc#arge #ea'

"1"1"""2""21"""B8#en a reci+rocating +um+ 'isc#arges i%e its +iston or+%unger mo-es in on%$ one 'irection9 it is terme' a

b sing%e acting unit

"1"1"""2""21"""Dentrifuga% +um+s con-ert rotating mec#anica% energ$ intokinetic energ$ t#en

' into +otentia% energ$ in t#e form of +ressure

"1"1"""2""21"""

A #ot &ater #eating s$stem circu%ator s#ou%'

c be -er$ uiet in o+eration

"1"1"""2""21"""AT#e ca+acit$ of a centrifuga% +um+

a -aries &it# 'isc#arge +ressure

"1"1"""2""21"""B

11


12/160

entrifuga% +um+ +o&er reuirements are 'ecrease' en

b t#e %itres mo-e' +er minute is 'ecrease'

"1"1"""2""21"""A rotar$ +um+

c s#ou%' be eui++e' &it# a re%ief -a%-e

"1"1"""2""21"""B8#en startingu+ a rotar$ +um+ $ou must be sure t#at t#e

b 'isc#arge -a%-e is o+en

"1"1"""2""21"""Rotar$ +um+s(

1. are #ig# +ressure +um+s 4. are +ositi-e 'is+%acement +um+s

"1"1"""2""21"""EA 'oub%eacting +um+

e is a +ositi-e 'is+%acement +um+

"1"1"""2""21"""BA -o%ute t$+e +um+

b #as a +rogressi-e%$ e*+an'ing s+ira% casing

"1"1"""2""21"""DA 'iffuser +um+(

1. #as stationar$ gui'e -anes surroun'ing t#e im+e%%er 2. #as a #ig#er efficienc$ t#an a -o%ute t$+e

"1"1"""2""21"""Turbine +um+s(

2. are #ig# +ressure +um+s 3. #as t#e %iui' gain energ$ in a number of im+u%ses

"1"1"""2""21"""AA centrifuga% +um+ consists of

a an im+e%%er surroun'e' b$ a casing

"1"1"""2""21"""ET#e ca+acit$ of a centrifuga% +um+ s#ou%' on%$ be re'uce' b$

e c%osing in t#e 'isc#arge -a%-e

"1"1"""2""21"""Ba-itation of a +um+ refers to9 en(

12


13/160

b t#e +um+ is fi%%e' &it# -a+our

"1"1"""2""21"""DRotar$ +um+s(

1. #a-e tig#t c%earances on a%% mo-ing +arts 3. are +ositi-e 'is+%acement units 4. s#ou%' not be starte' &it# 'isc#arge c%ose'

"1"1"""2""21"""Ef a +um+ is ca-itating at can $ou 'o to +re-entor re'uce t#e ca-itation;

e raise t#e suction +ressure

"1"1"""2""21"""DApositive displacementstan' b$+um+ &i%% #a-e

' t#e suction -a%-e o+en an' t#e 'isc#arge -a%-e o+en

"1"1"""2""21"""BPum+s #an'%ing cr$ogenic materia%s o+erate

b at e*treme%$ %o& tem+eraturesG"1"1"""2""21"""AA circu%ating +um+ is usua%%$

a connecte' &it# some t$+e of #eat e*c#anger s$stem

"1"1"""2""21"""A mu%tistage +um+ &ou%' be use'

c en t#e #ea' is great

"1"1"""2""21"""BTurbine +um+s are best suite' for

b %o& ca+acit$ #ig# +ressure ser-ice

Pump peration an! Maintenan"e

"1"1"""2""21"""APum+ &ear rings are insta%%e' on an im+e%%er b$ set scre&s9t#rea'ing or

a s#rinking

"1"1"""2""21"""8ear rings are usua%%$ constructe' of

13


14/160

c bron@e or cast iron

"1"1"""2""21"""B8earing rings(

1. are use' on im+e%%ers 2. are use' on t#e casing 4. re'uce t#e maintenance cost of t#e +um+

"1"1"""2""21"""EA stuffing bo*(

1. sto+s air %eaking into t#e casing en t#e +ressure is be%o& atmos+#eric 2. 'ecreases %eakage out of t#e casing en t#e +ressure is abo-e atmos+#eric 4. is fi%%e' &it# +acking

"1"1"""2""21"""Bec#anica% sea%s(

1. are use' ere %eakage is ob?ectionab%e 2. re+%ace stuffing bo*es 3. +ro-i'e a better sea% t#an +acking

"1"1"""2""21"""Dom+ression t$+e +acking(

1. +re-ents air from entering t#e +um+ 2. re'uces t#e maintenance cost on +um+s

"1"1"""2""21"""6antern rings(

2. are fe' b$ a %iui' 3. +ro-i'e a sea% to +re-ent air from entering t#e +um+ 4. are most%$ use' on #ig# %ift +um+s

a 19 29 3b 29 3c 29 39 4' 39 4e 19 2

"1"1"""2""21"""T#e sea% cage on t#e s#aft of a centrifuga% +um+

c 'istributes sea%ing &ater to t#e +acking

"1"1"""2""21"""BT#e main a'-antage of a +um+ using a mec#anica% sea% is

b %ess maintenance

"1"1"""2""21"""D

14


15/160

A s%ig#t %eakage is 'esire' bet&een t#e +um+ s#aft an'+acking of t#e ma?orit$ of +um+s in or'er to

' %ubricate t#e surfaces

"1"1"""2""21"""Bf a stuffing bo* is to +re-ent t#e ingress of air9 it iseui++e' &it#

b a sea% cage

"1"1"""2""21"""EAn$ %eakage occurring t#roug# t#e surfaces of a mec#anica%sea% &i%%

e be ra'ia% to t#e s#aft

"1"1"""2""21"""DT#e com+onent of a mec#anica% sea% ic# +re-ents a*ia%%eakage is

' t#e ring

"1"1"""2""21"""E8#at si@e of +acking s#ou%' $ou use9 to re+ack a +um+ g%an' #a-ing t#efo%%o&ing 'imensions( stuffing bo* bore F.H cm +um+ s#aft 'iameter H.7 cm

e .5 cm

"1"1"""2""21"""B0e& +um+ +acking s#ou%' be insta%%e'

b %oose enoug# to a%%o& %eakage for %ubrication

"1"1"""2""21"""B%e*ib%e cou+%ings &i%% com+ensate for

b a*ia% s#aft misa%ignment"1"1"""2""21"""A!#aft misa%ignment 'uring o+eration of a +um+ can be cause'b$ bearing &ear9 t#erma% e*+ansion9 an'

a s#aft f%e*ing

"1"1"""2""21"""DPro+er +riming an' -enting of a +um+ is im+ortant9 es+ecia%%$if' a mec#anica% sea% is use'

"1"1"""2""21"""BPriming of a centrifuga% +um+ refers to

b fi%%ing t#e +um+ casing &it# %iui' an' remo-ing t#e air

15


16/160

"1"1"""2""21"""DPriming a &ater +um+ means

' fi%%ing t#e +um+s casing an' suction %ine &it# &ater

"1"1"""2""21"""Bf t#e +acking g%an' of a centrifuga% &ater +um+ is %eaking toomuc#9 $ou s#ou%'

b tig#ten u+ t#e g%an' but +ermit a s%ig#t amount of %eakage

"1"1"""2""21"""E8#en %ubricating eui+ment9 t#e o+erator s#ou%' a%so c#eck for(

1. unusua% mac#ine noises 2. unusua% consum+tion of %ubricant 3. e*cessi-e #eat in bearing #ousing 4. e*cessi-e %eakage of %ubricant

"1"1"""2""21"""ost +um+ fai%ures9 'amage9 or bot# occurs

' 'ue to &rong rotation

"1"1"""2""21"""8#en a +um+ is o+erating9 $our ins+ection s#ou%' inc%u'e t#efo%%o&ing(

c $ou s#ou%' c#eck t#e 'isc#arge +ressure

"1"1"""2""21"""EA +%ugge' im+e%%er s$m+tom or resu%t &i%% be

e no %iui' being 'e%i-ere'

"1"1"""2""21"""Af +um+ s+ee' is too #ig#

a t#e 'ri-er ma$ be o-er%oa'e'

"1"1"""2""21"""Df a +um+ is running an' #as no 'isc#arge +ressure9 at &i%%$ou 'o;

' c#eck to see if t#e suction -a%-e is o+en

"1"1"""2""21"""Aou 'isco-er t#at $our fee' &ater +um+ is not 'e%i-ering sufficient&ater. A +ossib%e cause is

a t#e im+e%%er is +%ugge'

16


17/160

#ir Compression

"1"1"""2""21"""Aom+resse' air mac#iner$ &ou%' most %ike%$ be use' in

a coa% mines

"1"1"""2""21"""Dom+resse' air too%s ten' to be

' more e*+ensi-e t#an e%ectrica% too%s

"1"1"""2""21"""An a centrifuga% com+ressor t#e kinetic energ$ is con-erte'to +otentia% energ$ in t#e

a -o%ute9 'iffuser9 or bot#

"1"1"""2""21"""D

T#e com+ressor ic# &ou%' fa-our -o%ume o-er +ressure &ou%'be t#e' centrifuga%

"1"1"""2""21"""BPositi-e 'is+%acement air com+ressor t$+es are

b gear com+ressors

"1"1"""2""21"""D!ing%e stage reci+rocating air com+ressors

' cou%' #a-e t&o c$%in'ers

"1"1"""2""21"""EA be%t 'ri-en %ubricator is -er$ +o+u%ar on a

e s%i'ing -ane unit

"1"1"""2""21"""B


18/160


19/160

"1"1"""2""21"""DAir recei-ers

' must #a-e a safet$ -a%-e

$ubri"ation Prin"iples"1"1"""2""21"""ARe%ati-e to %ubrication9 one +%ace ere &ear is beneficia%is

a ne& babbit bearing surfaces ic# &ear smoot#

"1"1"""2""21"""DT#e intermes#ing of gear teet# is a +%ace ere %ubrication

' s#ock absor+tion is -er$ im+ortant

"1"1"""2""21"""DT#e %ubricant +erforms a number of functions. n'icate ic#of t#e fo%%o&ing are t#e most im+ortant(

1. re'uce &ear 4. re'uce friction

"1"1"""2""21"""DA materia% ic# is common%$ use' as a so%i' %ubricant is

' mo%$b'enum 'isu%+#i'e

"1"1"""2""21"""E

Crease is not a suitab%e %ubricant

e if a %arge amount of coo%ing is 'esire'

"1"1"""2""21"""A semiso%i' %ubricant(

c is %ess %ike%$ to 'ri+ or s+%as# from bearings

"1"1"""2""21"""E6ubricant for an antifriction bearing is

e barium an' %it#ium base grease

"1"1"""2""21"""D8#ic# t$+e of grease is t#e c#ea+est an' most common%$ use';

' ca%cium base

"1"1"""2""21"""AT#e +ro+ert$ of an oi% ic# in'icates its abi%it$ to su++orta %oa' is

19


20/160

a -iscosit$

"1"1"""2""21"""Af an oi%:s -iscosit$ c#anges muc# &it# %itt%e tem+eraturec#ange t#en it &i%% #a-e a

a %o& -iscosit$ in'e*

"1"1"""2""21"""D8#ic# of t#e fo%%o&ing #as t#e greatest effect ont#e -iscosit$ of a %ubrication oi%;

' tem+erature

"1"1"""2""21"""DT#e resistance of a %iui' to interna% 'eformationor s#ear is kno&n as(' -iscosit$

"1"1"""2""21"""A

8#ic# t$+e of oi% +ro'uces #ig#er f%ui' friction;

a a #ig# -iscosit$ oi%

"1"1"""2""21"""Ai% a''iti-es

a s#ou%' not affect a%% ot#er c#aracteristics great%$

"1"1"""2""21"""Bf $ou 'esire an oi% to f%o& at a muc# %o&er tem+erature $ou&ou%' most %ike%$ a''

b +our +oint 'e+ressants

"1"1"""2""21"""


21/160

' 'ensit$

"1"1"""2""21"""EA form of %ubrication ic# reuires continua% motion of as#aft or surface ise f%ui' fi%m %ubrication

"1"1"""2""21"""A%ui' fi%m %ubrication

a is use' for #ea-$ %oa's

"1"1"""2""21"""B%ui' fi%m %ubrication

b is a%so ca%%e' f%oo' %ubrication

"1"1"""2""21"""En a force' %ubrication s$stem9 a +um+ su++%ies oi%

n'er +ressure for t#e bearings.

"1"1"""2""21"""D6arge ?ourna% or s%ee-e bearings #a-e groo-es

' in t#e non+ressure area

"1"1"""2""21"""BA %arge ?ourna% bearing ic# is running #otter t#an norma%can be coo%e' b$

b %oosening t#e bearing ca+s

"1"1"""2""21"""BA t#rust bearing ic# 'oes not uti%i@e t#e oi% &e'ge+rinci+%e of %ubrication is t#e

b co%%ar t$+e

"1"1"""2""21"""Bne of t#e main functions of t#e %ubricant in a sea%e'9grease t$+e antifriction bearing is

b sea%ing

"1"1"""2""21"""E

A ?ourna% bearing

e su++orts a s#aft

"1"1"""2""21"""AT#rust bearings(

1. are use' on reaction turbines 2. +re-ent t#e turbine rotor mo-ing a*ia%%$

21


22/160

4. are %ubricate' &it# t#e same oi% as t#e main bearings

"1"1"""2""21"""T#e %ubricant for an antifriction bearing

c cou%' be a semiso%i' %ubricant

"1"1"""2""21"""BA co%%ar t#rust bearing(

2. can +re-ent a rotating s#aft from mo-ing bot# a*ia% 'irections 3. #as boun'ar$ %ubrication

"1"1"""2""21"""BA t#rust bearing

b +re-ents a*ia% mo-ement of t#e s#aft

"1"1"""2""21"""A

An antifriction bearing

a cou%' be a t#rust bearing

"1"1"""2""21"""EA co%%ar t#rust bearing

e #as boun'ar$ %ubrication

"1"1"""2""21"""A t$+e of antifriction bearing is t#e ba%% bearing.

"1"1"""2""21"""sing +ressuri@e' air to b%o& out a c%eane' bearing

c &i%% cause t#e bearing to become >+itte'>

"1"1"""2""21"""A8#en re+%acing or remo-ing an antifriction ba%% bearing9 t#ea++%ie' force s#ou%'

a not be transmitte' t#roug# t#e bearing ba%%s

"1"1"""2""21"""E

A++%$ing insta%%ation forces t#roug# t#e ba%%s of a bearingcan cause

e brine%%ing

"1"1"""2""21"""DA norma% antifriction bearing tem+erature o+erating range is

' H5 to 7" 'egrees

22


23/160


24/160

c%ose t#e s&itc# is

e to +re-ent t#e s&itc# from c%osing 'ue to gra-it$

"1"1"""2""21"""T#e batter$ of an e%ectrica% circuitc su++%ies e%ectromoti-e force

"1"1"""2""21"""DT#e unit of measure for e%ectrica% current f%o& is t#e

' Am+ere

"1"1"""2""21"""EAtoms t#at #a-e greater numbersof e%ectrons in t#e outer s#e%%are

e not goo' con'uctors

"1"1"""2""21"""B

E%ectrons are negati-e%$ c#arge' +artic%es

b orbiting about t#e nuc%eus of an atom

"1"1"""2""21"""Don-entiona% current f%o& is from +ositi-e to negati-e.

' on-entiona%

"1"1"""2""21"""Af an e%ectrica% +otentia% is +%ace' across acon'uctor9 t#e e%ectrons &i%% 'rift from t#e negati-e en'to&ar's t#e +ositi-e en' of t#e con'uctor9 assuming t#ee%ectron t#eor$.

"1"1"""2""21"""BA materia% t#at con'ucts e%ectrica% current is ca%%e'

b a con'uctor

"1"1"""2""21"""AT#e e%ectrica% +ressure t#at causes current f%o& t#roug# acircuit is

a e%ectromoti-e force

"1"1"""2""21"""DT#e f%o& of e%ectrons in a uniform 'irection from atom to atomt#roug# a circuit9 is kno&n as

' current

"1"1"""2""21"""EAn insu%ator is materia% t#at &i%% not con'uctan e%ectrica% current.

24


25/160


26/160

b one o#m

"1"1"""2""21"""urrent f%o& is in-erse%$ +ro+ortiona% to t#e

c resistance

"1"1"""2""21"""DT#e -a%ue of t#e current f%o& in an e%ectric circuit9 eret#e -o%tage is 12 -o%ts an' t#e resistance is 3 o#ms is' 4 am+eres

"1"1"""2""21"""AT#e tota% resistance of t#ree resistances in a seriescircuit can be gi-en as

a R1 ) R2 ) R3

010100020021000B

T#e eui-a%ent resistance of t#ree resistances 1" o#ms925 o#ms an' 5" o#ms connecte' in +ara%%e% is

b H.25 o#ms

"1"1"""2""21"""A con'uctor:s resistance is

c in-erse%$ +ro+ortiona% to its crosssectiona% area

"1"1"""2""21"""Aost con'uctors ten' to

a increase in resistance &it# increase in tem+erature

"1"1"""2""21"""Df t#e a++%ie' -o%tage in a circuit is 12" -o%tsan' t#e current f%o& is 3 am+eres t#e resistanceof t#is circuit is

' 4" #ms

"1"1"""2""21"""Io%tage is

c e%ectromoti-e force

"1"1"""2""21"""AE%ectromoti-e force

a is ca+ab%e of mo-ing a uantit$ of e%ectrons at some rate +er +erio' of time

"1"1"""2""21"""An am+ere is t#e measurement of current f%o&.

26


27/160

"1"1"""2""21"""E

T#e -o%t is an e%ectromoti-e force.

"1"1"""2""21"""Bn'er norma% circumstances9 t#e #eat +ro'uce' b$ t#e e%ectrica%&ires of a circuit is -er$ sma%% 'ue to t#e

b %o& resistance of t#e con'uctor

"1"1"""2""21"""T#e force reuire' to +ro'uce a current of one am+ere t#roug#a resistance of one o#m9 isc one -o%t

"1"1"""2""21"""BT#e unit of current f%o& is t#e

b am+ere

"1"1"""2""21"""AT#e o++osition a 'e-ice or materia% offers to t#e f%o& ofe%ectric current9 is kno&n as(

a a resistance

"5"3"""2""42"""HH""J5JAn e%ectric motor is 'esigne' for a current of 3" am+eres&it# an a++%ie' -o%tage of 22" -o%ts.

a ca%cu%ate t#e +o&er consume'

b ca%cu%ate t#e efficienc$ of t#e motor if t#e rate' out+ut is H.27 k8

Ans&ers(

a = KKKKKHH""KKKKKKKKK &atts

b = KKKKKKKKK5KKKKKKK

"1"1"""2""21"""D8#at +o&er is 'issi+ate' b$ a resistor &it# a su++%$ -o%tage of12" -o%ts an' current of F am+eres;

' H" &atts

"1"1"""2""21"""AE%ectrica% +o&er can be 'etermine' b$ t#e formu%a

a P = E

"1"1"""2""21"""BT#e basic unit of mec#anica% or e%ectricpoweris t#e

27


28/160

b &att

"1"1"""2""21"""ET#e -o%tage reuire' to be su++%ie' to a 12 k8 motor 'ra&ing24 am+eres is

e 5"" -o%ts

"1"1"""2""21"""Df t#e +o&er 'issi+ate' b$ a resistor is 1.2 k8 en su++%ie' &it#11" -o%ts9 t#e am+erage &i%% be' 1"." am+eres

"1"1"""2""21"""B0eg%ecting t#e efficienc$ of a 15 k8 motor connecte' to a 4""-o%t su++%$9 t#e am+erage &i%% be

b 37.5 am+eres

"1"1"""2""21"""DT#e &att is an e%ectrica% unit of measure for

' +o&er

"1"1"""2""21"""T#e basic unit of e%ectrica% +o&er is t#e &att9 ic# is t#eresu%t ofc -o%ts times am+eres

Magnetism an! Ele"tromagnetism

"1"1"""2""21"""Bagnetic f%u* can be sai' to be

b %ines of force outsi'e a magnet an' f%o&ing 0 to !

"1"1"""2""21"""Aurrent f%o& 'irection an' intensit$ &i%%

a affect magnetic fie%' 'irection an' intensit$

"1"1"""2""21"""8#en a materia% or substance 'oes not form a magnetic f%u*

easi%$ it is sai' to #a-e

c re%uctance

"1"1"""2""21"""ET#e s+ace or @one aroun' a magnet t#roug# ic# %ines offorce tra-e% is terme'e magnetic fie%'

"1"1"""2""21"""B

28


29/160

ara'a$ 'isco-ere'

b t#at a con'uctor &i%% #a-e a -o%tage in'uce' if it cuts magnetic f%u*

"1"1"""2""21"""f a con'uctor is #e%' stationar$ an' a magnetic fie%' ismo-e' across it9 it forms at is kno&n as

c generator action

Magnetism an! Ele"tromagnetism

"1"1"""2""21"""D8#en a con'uctor is mo-e' to cut magnetic f%u* %ines at anang%e of " 'egrees

' -o%tage generate' &i%% be ma*imum

"1"1"""2""21"""D8#en magnetic f%u* %ines tra-e% an' meet in o++osing'irections t#e resu%t can be

' motor action

"1"1"""2""21"""AA con'uctor su++%ie' &it# current i%e in a magnetic fie%'&i%%

a ten' to mo-e at rig#t ang%es to t#e f%u* %ines

"1"1"""2""21"""D

f t&o un%ike +o%es are +%ace' a'?acent to eac# ot#er t#ere is

' a force of attraction bet&een t#e magnets

"1"1"""2""21"""E8#en current f%o&s in a con'uctor

e a circu%ar magnetic fie%' is set u+ aroun' t#e con'uctor

"1"1"""2""21"""T#e tota% number of %ines of force +er suare metrein a magnetic fie%' is

c ca%%e' t#e magnetic f%u*

"1"1"""2""21"""Dagnetic fie%' 'irection an' intensit$ 'e+en' on t#e

' 'irection an' intensit$ of current f%o&

"1"1"""2""21"""D8#en %ike +o%es of a magnet are +%ace' a'?acent to eac# ot#er

29


30/160

t#e$ &i%%

' re+e% eac# ot#er

"1"1"""2""21"""EA +ro+ert$ of a magnet is t#at it &i%% a%&a$s +oint in t#e nort#an' sout# 'irection9 en

e free%$ sus+en'e' in t#e air

"1"1"""2""21"""Dron an' stee% ma$ be magneti@e' b$ rubbing t#e meta% &it#

' a magnet

"1"1"""2""21"""ET#e +ro+ert$ ic# 'etermines et#er or not a materia% &i%%be easi%$ magneti@e' or not is ca%%e'

e +ermeabi%it$

"1"1"""2""21"""BT#e +ro+ert$ of resistance to con'ucting magnetic %ines of forceis kno&n as

b re%uctance

"1"1"""2""21"""T#e ma*imum -o%tage generate' b$ a sing%e %oo+ D generatoroccurs en t#e con'uctor is cutting t#e magnetic %ines offorce at an ang%e of

c " 'egrees

"1"1"""2""21"""D8#en using %eming:s 6eft


31/160

"1"1"""2""21"""BT#e rig#t #an' ru%e is use' to

b 'etermine t#e 'irection of in'uce' current f%o&

Ele"tri"al Metering evi"es

"1"1"""2""21"""DBatteries

' +ro'uce a stea'$ D -o%tage

"1"1"""2""21"""DT#e most common measurement ma'e &it# a meter is

' -o%tage

"1"1"""2""21"""A8#en using an e%ectrica% meter to c#eck t#at a circuit issafe to &ork on9 it is im+ortant to -erif$ t#e +ro+er sca%e9current9 or bot# t#at is being use' because

a it ma$ a++ear t#at no -o%tage or current is +resent an' t#erefore safe

"1"1"""2""21"""A c%am+on ammeter measures current f%o& b$ using

c a basic transformer +rinci+%e

"1"1"""2""21"""A

%am+on ammeter rea'ings ma$ be inaccurate if

a ?a&s are 'irt$ or misa%igne'

"1"1"""2""21"""A ki%o&att #our meter #as a sma%% motor ic#

c #as a s+ee' +ro+ortiona% to +o&er consum+tion

"1"1"""2""21"""Eti%it$ com+anies #a-e a surc#arge to t#eir customers base'on

e +eak 'eman'

"1"1"""2""21"""DA -o%tmeter is connecte' to a circuit

' in +ara%%e%

"1"1"""2""21"""Ammeters are connecte' &it# t#e negati-e or b%ack%ea' connecte' to t#e

31


32/160

c negati-e si'e of t#e circuit

"1"1"""2""21"""D8#en rea'ing t#e 'ia%s of a +o&er meter9 rea'

' t#em from rig#t to %eft

"1"1"""2""21"""ET#e b%ack 'eman' +ointer of a +o&er meter

e must be manua%%$ reset

"1"1"""2""21"""A +o&er meter

c rea's on%$ a sma%% +ercentage of t#e actua% %oa'

Motors an! Generators

"1"1"""2""21"""T#e e%ectromagnetic fie%' for a D mac#ine is terme' t#e

c fie%' +o%es

"1"1"""2""21"""DT#ere are t#ree main t$+es of D generatorsJ series9 s#untan' com+oun' &oun'. Eac# is

' se%fe*cite'

"1"1"""2""21"""EA%ternators must run at constant s+ee' in or'er to maintain

e freuenc$

"1"1"""2""21"""AT#e out+ut -o%tage of a s#unt D generator ma$ be -arie' b$a'?usting t#e

a fie%' r#eostat

"1"1"""2""21"""BT#e main com+onents of a D mac#ine are t#e $oke or frame

ic# su++orts t#e fie%' +o%es an' t#e rotoric# is ca%%e' an armature.

"1"1"""2""21"""An or'er to +ro'uce t#e strengt# of magnetic f%u* reuire' in%arger D mac#ines

a e%ectromagnets are use'

32


33/160

"1"1"""2""21"""ET#e armature core of a D mac#ine is bui%t u+ of %aminationsofe si%icon stee% +%ates

"1"1"""2""21"""BA s#unt t$+e D generator #as near%$ constant out+ut -o%tage.

"1"1"""2""21"""ET#e magnetic fie%' in a D mac#ine ma$ be su++%ie' b$ +ermanentmagnets in sma%% units. 6arge D mac#ines use fie%' +o%es t#atare essentia%%$

e e%ectromagnets

"1"1"""2""21"""AT#e t#ree main t$+es of D generators are t#e(

1. com+oun' &oun' 3. series &oun'

5. s#unt &oun'

"1"1"""2""21"""DT#e %oa' current #as no effect on t#e fie%' e*citation of a' se+arate%$ e*cite' generator

"1"1"""2""21"""BT#ree factors ic# contro% t#e e%ectromoti-e force 'e-e%o+e'b$ a D generator are t#e(

2. s+ee' &it# ic# con'uctors cut t#e magnetic %ines of force 3. number of con'uctors cutting t#e magnetic %ines of force 5. strengt# of t#e magnetic f%u*

"1"1"""2""21"""AT#e -o%tage +ro'uce' in eac# +#ase of a t#ree +#ase generatoris 'is+%ace' b$ 12" e%ectrica% 'egrees from t#e ot#er+#ases.

"1"1"""2""21"""AT#e fie%' strengt# of an a%ternator can be a'?uste' b$ -ar$ingt#e am+%itu'e of t#e D +o&er su++%ie' to t#e

a rotating fie%'

"1"1"""2""21"""BT#e fie%' strengt# of an a%ternator ma$ be c#ange' b$-ar$ing t#e am+%itu'e of t#e D +o&er9 su++%ie' to t#erotating fie%' b$(

1. t#e use of a fie%' r#eostat 4. e%ectronic contro%

33


34/160

"1"1"""2""21"""An a'-antage of #a-ing an a%ternator &it# a rotating fie%' is9t#at t#e si@e of t#e rotating mass is

c re'uce'

"5"5"""2""21"""Determine t#e s+ee' of a s$nc#ronous motor o+erating &it# a %inefreuenc$ of H" Ans&er =>90(39."1

"1"1"""2""21"""DT#e connection +ro-i'e' on D motors to su++%$ t#e armature &it#

+o&er

' is a commutator

"1"1"""2""21"""T#e s+ace aroun' a magnet9 t#roug# ic# t#e imaginar$ magnetic%ines of force are consi'ere' to tra-e%9 is kno&n as t#e

c magnetic fie%'

"1"1"""2""21"""AA common use for a D generator is

a +o&er su++%$ for an e%e-atorG

"1"1"""2""21"""n a series &oun' D generator2

c %oa' current +asses t#roug# t#e fie%' &in'ings

"1"1"""2""21"""AA r#eostat or >-o%tage regu%ator> of a D s#unt &oun'generator is use' to

a regu%ate t#e strengt# of t#e e%ectromagnetic fie%'

"1"1"""2""21"""A8#en s$nc#roni@ing an a%ternatorJ -o%tage9 +#ase an'freuenc$ must a%% be t#e same as &e%% as

a +#ase seuence

"1"1"""2""21"""T#e fie%' r#eostat in a D generator is use' to a'?ust t#eKKKKKKKKKKKKKKK of t#e motor.

34


35/160


36/160

"1"1"""2""21"""DA H +o%e a%ternator +ro'ucing H"


37/160

"1"1"""2""21"""E!$nc#ronous motors #a-e construction t#at is i'entica% to

e a%ternators

"1"1"""2""21"""DAn A motor ic# &i%% 'ro+ out of s$nc#ronism an' sim+%$tri+ en o-er%oa'e' is t#e

' s$nc#ronous motor

"1"1"""2""21"""DPermanent magnets are use' for

' t#e sma%%est D motors an' generators

"1"1"""2""21"""Brus# gear for D mac#ines #a-e brus#es ma'e from carbon

because t#e$(

1. are softer 2. &ear to a smoot# finis# 5. #a-e a %o& coefficient of friction

"1"1"""2""21"""DA r#eostat is use' to -ar$ t#e fie%' strengt# in a Dmac#ine.

"1"1"""2""21"""D!$nc#ronous motors are use' to

' im+ro-e t#e +o&er factor of a +o&er s$stem

"1"1"""2""21"""DTo transfer t#e +o&er to or from t#e rotor of a%ternators orsome A motors' s%i+ rings are em+%o$e'

"1"1"""2""21"""A++arent +o&er is t#e +o&er

c su++%ie' b$ t#e uti%it$

Transformers

"1"1"""2""21"""A8#en A action causes a counter current in a coi% it isterme'

a se%f in'uctance

37


38/160

"1"1"""2""21"""8#en magnetic f%u* +ro'uce' b$ one coi% in'uces an E in asecon' coi% it is ca%%e'

c mutua% in'uctance

"1"1"""2""21"""BA transformer &orks on t#e +rinci+%e of

b magnetic in'uction

"1"1"""2""21"""Ef E , E = 0 , 0 t#en 0 &i%% eua% + s + s s

e 0 E , E + s +

"1"1"""2""21"""

T#ree ma?or %osses ic# occur in a transformer are iron%osses9 co++er %osses an'c f%u* %eakage

"1"1"""2""21"""o++er %osses in a transformer are re'uce' b$

c using %arger 'iameter &ire

"1"1"""2""21"""DAn active currenttransformer s#ou%' ne-er

' #a-e its secon'ar$ circuit o+ene'

"1"1"""2""21"""EA +#enomena +ro'uce' b$ e%ectronic s&itc#gear ic# canresu%t in e*cessi-e%$ #ig# -o%tages in transformers are kno&nas

e #armonic 'istortion

"1"1"""2""21"""DA 'e-ice use' to c#ange t#e -o%tage an' current from one %e-e%to anot#er9 is kno&n as a,an

' transformer

"1"1"""2""21"""An instrumenttransformer used to measure voltageis ca%%e' a

c +otentia% transformer

"1"1"""2""21"""ETransformers are rate' in terms of(

1. Io%t am+eres 3. Ni%o-o%t am+eres

38


39/160

"1"1"""2""21"""AT#e ca+acit$ of a transformer can be increase' b$(

1. submerging t#e core an' &in'ings in a tank of oi% 3. force' air coo%ing t#e oi% in a #eat e*c#anger 5. force' air coo%ing of t#e core

"1"1"""2""21"""A transformer #as a +rimar$ -o%tage of 5"" -o%ts an' 2" turnson t#e +rimar$ &in'ing. f t#e secon'ar$ &in'ing #as 5 turnst#e -o%tage of t#e secon'ar$ is

c 125 -o%ts

"1"1"""2""21"""ET#e -o%tage in'uce' in t#e secon'ar$ &in'ings of t#etransformer9 is in-erse%$ +ro+ortiona% to t#e turns ratio of t#e

transformer.

"1"1"""2""21"""Eurrent transformers ste+ 'o&n t#e current rat#er t#an t#e

e -o%tage

"1"1"""2""21"""ATransformer coo%ing oi% #as

a a -er$ #ig# s+ecific #eat

"1"1"""2""21"""!ome of t#e #a@ar's of transformer coo%ing oi% can becom+ensate' for b$ a''ing

c c#%orinate' #$'rocarbons

"1"1"""2""21"""DTransformers s#ou%' be ins+ecte' at %east' annua%%$

Ele"tri"al istribution Cir"uits

"1"1"""2""21"""A t$+ica% e*tra %o& -o%tage 'e-ice &ou%' be a

c 'oor be%%

"1"1"""2""21"""A +rime factor in 'etermining t#e -o%tage to be use' in acircuit is

39


40/160

c 'egree of access to eui+ment

"1"1"""2""21"""B6o& -o%tage s$stems ma$ #a-e an acce+tab%e -o%tage -ariationof +%us or minus

b 5

"1"1"""2""21"""ET#e abi%it$ of an e%ectrica% circuit to store a c#arge ofe%ectricit$ e-en after t#e circuit is o+ene' is terme'

e ca+acitance

"1"1"""2""21"""8#en &orking &it# #ig# -o%tage s$stems9 t#e minimum 'istanceof a++roac# s#ou%' be

c 2 metres

"1"1"""2""21"""BT#e best t$+e of 'iagram for s#o&ing su++%$ an' 'istributions$stems is t#e

b one%ine 'iagram

"1"1"""2""21"""An e%ectrica% 'istribution s$stem is com+ose' of ser-ice9fee'ers an'

c branc# circuits

"1"1"""2""21"""BT#e uti%it$:s res+onsibi%it$ &i%% not go be$on' t#e

b first o-ercurrent 'e-ice

Intro!u"tion to Instrumentation

"1"1"""2""21"""B8#en a +rocess -ariab%e #as no met#o' of sen'ing informationto t#e fina% contro% e%ement t#e s$stem is kno&n as

b an o+en %oo+ s$stem

"1"1"""2""21"""DAn o+en %oo+ contro% s$stem reuires

' constant attention

"1"1"""2""21"""A +rocess -ariab%e ic# is a'?uste' in or'er to maintain orac#ie-e some 'esire' -a%ue of anot#er -ariab%e is terme' t#e

40


41/160

c mani+u%ate' -ariab%e

"1"1"""2""21"""EA contro% %oo+ contro%%er

e constant%$ com+ares in+ut signa%s to t#e set +oint

"1"1"""2""21"""EA common air +ressure range for +neumatic contro% s$stems is

e 2" to 1"" kPa

"1"1"""2""21"""BA -er$ im+ortant reuirement for a +neumatic contro% s$stemis

b air su++%$ must be c%ean an' 'r$

"1"1"""2""21"""DT#e a++aratus ic# con-erts current signa%s to +neumatic an'+neumatic to current signa%s is ca%%e' a

' trans'ucer

"1"1"""2""21"""DA control deviceic# &i%% c#ange one form of energ$ intoanot#er form of energ$ is t#e

' trans'ucer

"1"1"""2""21"""AA 'e-ice ic# &i%% cause a -isib%e %ig#t signa% to become aninstrument ana%og signa% is t#e

a +#otoe%ectric trans'ucer

"1"1"""2""21"""BA >contro%> s#ou%' be consi'ere' as a s+ecia% 'e-ice ic#

b tries to maintain a set +oint

"1"1"""2""21"""Automatic s$stems ic# can make 'ecisions are terme'

c %ogic s$stems

Intro!u"tion to Pro"ess Measurement

"1"1"""2""21"""AAn inc%ine' manometer is common%$ use'

a en -er$ %o& +ressures or -acuums are being measure'

41


42/160

"1"1"""2""21"""DA Bour'on tube is often in t#e s#a+e of a s+ira% so t#at

' more +o&er an' tra-e% of t#e out+ut occurs

"1"1"""2""21"""8#en a 'ia+#ragm 'e-ice is use' for boi%er &ater %e-e%measurement9 t#e boi%er +ressure is com+ensate' for oroffset b$

c a++%$ing t#e +ressure to bot# si'es of t#e 'ia+#ragm

"1"1"""2""21"""Ene of t#e most &i'e%$ use' +rocess -ariab%es in a s$stem is

e f%o&

"1"1"""2""21"""n a g%ass stem t#ermometer t#e s+ace abo-e t#e %iui' isusua%%$

c ma*imum -acuum

"1"1"""2""21"""DA t#ermocou+%e &i%% +ro'uce a D mi%%i-o%tage ic#

' is not uite +ro+ortiona% to tem+erature 'ifferences

"1"1"""2""21"""ET#e Bour'on tube is often s#a+e' in t#e form of a >>9 #a-ing anarc s+an of about

e 27" 'egrees

"1"1"""2""21"""BT#e +ur+ose of a s+ira% or a #e%i* Bour'on tube is

b to +ro-i'e a greater 'egree of rotation

"1"1"""2""21"""C%ass t#ermometers &it# a mercur$ fi%% are sometimes+ressuri@e' &it# nitrogen so

c t#at t#e$ can be use' at #ig#er tem+eratures

"1"1"""2""21"""ETem+eratures are measure' b$

e t#ermocou+%es

"1"1"""2""21"""DT#e -ariab%e area meter consists of' a ta+ere' tube in ic# t#e f%ui' being measure' f%o&s t#roug# t#e tube from t#e bottom to t#e to+

"1"1"""2""21"""EA bimeta% t#ermostat reacts to c#anges of

42


43/160

e tem+erature

"1"1"""2""21"""B8#en a f%oat is use' for measuring %e-e%9 an' insta%%ation&it#in a -esse% is im+ractica%9 a 'e-ice often use' is t#e

b f%oat cage

"1"1"""2""21"""DRe%ati-e to f%o&9 -e%ocit$ is kinetic energ$ an' en-e%ocit$ increases9 t#e

' +otentia% energ$ in t#e form of +ressure &i%% 'ecrease

"1"1"""2""21"""6iui' must be in its -a+our form

c en a c#romatogra+# is being use'

""2""21"""BA c#romatogra+# uses e%ectronic 'e-ices ic#

b #a-e in-erse resistance +ro+erties re%ati-e to tem+erature

"1"1"""2""21"""DT#e e%ectrica% out+ut from a t#ermocou+%e is measure' b$ a

' mi%%i-o%tmeter

"1"1"""2""21"""BA t#ermocou+%e consists of

b t&o 'issimi%ar &ires connecte' toget#er to form a #ot an' a co%' ?unction

%asi" Control $oop Components

"1"1"""2""21"""BA f%a++erno@@%e assemb%$ is basic to a%%

b transmitters

"1"1"""2""21"""T#e no@@%e recei-es a constant air su++%$ +ressure ofa++ro*imate%$

c 14" kPa

"1"1"""2""21"""AT#e out+ut +ressure signa% of a transmitter re%a$ is usua%%$

a 'irect an' +ro+ortiona% to no@@%e +ressure

43


44/160

"1"1"""2""21"""AA t&o+osition contro%%er com+ares con'itions to a set +ointan'

a &i%% start or sto+ a +rocess

"1"1"""2""21"""E8#en contro%%er out+ut is +ro+ortiona% to t#e amount of'e-iation9 t#e contro%%er ise +ro+ortiona%

"1"1"""2""21"""BA +ro+ortiona% on%$ contro%%er

b cannot maintain set +oint e*ce+t at 5"

"1"1"""2""21"""B

A recor'er uti%i@ing a s+ira% Bour'on tube &i%% #a-e a +enmo-ement

b +ro+ortiona% to t#e c#ange in tube +ressure

"1"1"""2""21"""D8#en a recor'er recei-es a signa% from a transmitter9 t#erecor'er incor+orates a

' ca+su%e or be%%o&s

"1"1"""2""21"""A8#en an o+erator uses RT 'is+%a$s9 t#e com+uter contro%+ane%

a often #as a number of 'e'icate' recor'ers

"1"1"""2""21"""BA contro% -a%-e

b is a form of -ariab%e resistance in a +i+ing s$stem

"1"1"""2""21"""DA -a%-e actuator

' +osition is a function of contro%%er out+ut

e causes a -a%-e to a%&a$s fai% o+en

"1"1"""2""21"""Dost so%enoi' -a%-es are un%ike g%obe -a%-es in t#at u+stream%ine +ressure &i%%

' act to c%ose t#e -a%-e

44


45/160

%asi" %oiler Instrumentation an! Control Systems

"1"1"""2""21"""Bn a +ackage' boi%er a number of e%ectrica% s&itc#esconnecte' in series can be categori@e' as

b inter%ocks

"1"1"""2""21"""DA combustion air +ro-ing s&itc#

' senses &in'bo* +ressure

"1"1"""2""21"""AA %ea' su%+#i'e ce%% is sensiti-e to R ra$s an'

a its resistance to current f%o& -aries in-erse%$ &it# ra$

emissions

"1"1"""2""21"""To o+erate t#e t$+e of f%ame fai%ure 'e-ice ic# incor+oratesa %ea' su%+#i'e ce%%9 it must recei-e

c infrare' ra$s

"1"1"""2""21"""BT#e function of a f%ame fai%ure 'e-ice is to

b s#ut off t#e fue% en t#e burner f%ame goes out

"1"1"""2""21"""E

8#ic# of t#e fo%%o&ing is a f%ame sensing 'e-ice;

e scanner

"1"1"""2""21"""DA f%ame fai%ure 'e-ice

' &i%% s#ut off t#e fue% to t#e burner

"1"1"""2""21"""EBoi%er mo'u%ating fee'&ater contro% f%o& rate 'e+en's on

e set +oint9 %e-e%9 an' -a%-e +osition

"1"1"""2""21"""B8it# sing%e e%ement fee'&ater contro% t#e %e-e% transmitterout+ut is

b +ro+ortiona% to 'rum %e-e%

"1"1"""2""21"""ET#e secon' e%ement of a t&o e%ement fee'&ater contro% s$stem

45


46/160

com+ensates for or offsets

e s#rink an' s&e%%

"1"1"""2""21"""AA boi%er contro% transfer or se%ector station

a can be use' to manua%%$ o-erri'e automatic contro% %oo+s

"1"1"""2""21"""An automatic fee'&ater regu%ator is use' to

c maintain a constant &ater %e-e% in t#e boi%er

"1"1"""2""21"""An a t&o e%ement fee'&ater contro% t#e fo%%o&ing items aremeasure'(

a boi%er &ater %e-e% an' steam f%o&

"1"1"""2""21"""n a steam boi%er &it# sing%e e%ement fee'&ater contro%9t#e fo%%o&ing item is measure'(

c boi%er &ater %e-e%

"1"1"""2""21"""AAn automatic boi%er 0 or o+erating contro% s&itc# #as ana'?ustment for cutin or cutout -a%ue an' anot#er for

a a 'ifferentia% bet&een t#e t&o

"1"1"""2""21"""EA +ackage' steam boi%er mo'u%ating combustion contro% s$stem&i%% routine%$

e maintain boi%er steam +ressure &it#in a 'esire' range

"1"1"""2""21"""Ao'u%ating combustion contro% &i%%

a c#ange air an' fue% f%o& +ro+ortiona%%$ to steam +ressure c#ange

"1"1"""2""21"""B

o'u%ating +ressure contro%

b &i%% contro% t#e fue% an' air f%o& to t#e boi%er

"1"1"""2""21"""o'u%ating combustion contro% on a #eating boi%er is accom+%is#e'b$c c#anging t#e amount of fue% an' air to t#e burner

46


47/160

$ow'water (uel Cuto)s

"1"1"""2""21"""A f%oat o+erate' %o&&ater fue% cutoff #as its s&itc#se+arate' from boi%er +ressure b$

c a f%e*ib%e 'ia+#ragm

"1"1"""2""21"""BA mercur$ s&itc# bu%b is un'er #ig# -acuum an' contains inertgas

b to +re-ent corrosion of t#e contacts

"1"1"""2""21"""A f%oat o+erate' %e-e% contro%

c is on%$ use' on sma%% boi%ers

"1"1"""2""21"""A-er#eating of boi%er #eating surfaces 'ue to %o& &ater

a is t#e main cause of boi%er fai%ure

"1"1"""2""21"""DA %o& &ater fue% cutoff is fitte' to a boi%er to +re-ent' 'amage to t#e boi%er from an o-er#eate' con'ition

"1"1"""2""21"""ET#e +ur+ose of a %o& &ater fue% cutoff is to

e s#ut off t#e fue% su++%$ en t#e &ater %e-e% gets too %o&

"1"1"""2""21"""AA %o& &ater fue% cutoff ma$ be acti-ate' b$

a %o&ering t#e &ater %e-e% in t#e boi%er

"1"1"""2""21"""ET#e !A co'e states t#at a boi%er not un'er continuousatten'ance must be eui++e' &it# a %o&&ater fue% cutoffic#

e ser-es no ot#er +ur+ose

"1"1"""2""21"""AA %o&&ater fue% cutoff ic# ser-es no ot#er +ur+ose

a cannot be eui++e' &it# iso%ation -a%-es

"1"1"""2""21"""A %o&&ater fue% cutoff s&itc# s#ou%' c%ose t#e automaticfue% -a%-eMs en t#e &ater %e-e% is

47


48/160

c 1 to 2.5 cm abo-e t#e bottom gage g%ass nut

"1"1"""2""21"""BA #ot &ater boi%er %o&&ater fue% cutoff

b cannot be teste' 'uring routine boi%er o+eration

"1"1"""2""21"""T#e 'rain of a #ot &ater boi%er %o&&ater fue% cutoff s#ou%'be o+ene' to f%us# out an$ 'ebris

c &eek%$

"1"1"""2""21"""BTo test a %o& &ater fue% cutoff

b %o&er t#e &ater %e-e% unti% t#e burner s#uts 'o&n

"1"1"""2""21"""A

T#e f%oat c#amber of t#e %o& &ater cutoff is b%o&n out oftento +re-ent

a t#e c#amber co%%ecting se'iment

"1"1"""2""21"""T#e most re%iab%e met#o' of c#ecking or testing a %o&&ater fue%cut off is toc %o&er t#e &ater in t#e boi%er to t#e %e-e% ere t#e burner s#ou%' cut out

"1"1"""2""21"""T#e %o& &ater cutoff can be teste' b$c s#utting off t#e fee'&ater

%oiler Programming Controls

"1"1"""2""21"""Automatic boi%er +rogramming contro%s

c reuire an 0 or t&o+osition contro% s&itc#

"1"1"""2""21"""DAn interru+te' +i%ot of an automatic boi%er

' %ig#ts9 com+%etes a tria%9 an' e*tinguis#es after a main f%ame tria%

"1"1"""2""21"""T#e function of a +rogramming contro% is

c to regu%ate combustion contro%s 'uring startu+

"1"1"""2""21"""D

48


49/160

Boi%er furnaces are +urge'' so t#at combustib%es are fu%%$ remo-e' +rior to ignition

"1"1"""2""21"""AAutomatic boi%er %iui' fue% manua% -a%-es s#ou%' be o+ene'

a +rior to +re+urging

"1"1"""2""21"""AT#e o+erating +ressure contro% &i%% contro% t#e

a steam +ressure in t#e boi%er

"1"1"""2""21"""T#e secon' from %ast ste+ in an automatic boi%er +rogramme's#ut'o&n seuence is

c +ost +urge

"1"1"""2""21"""8it# automatic fue% fire' boi%er +rogramme' contro% t#enorma% firing +erio' begins a++ro*imate%$c H" secon's after D fan starts

"1"1"""2""21"""An a gas fire' automatic boi%er a norma% +rogramme' startu+takes a++ro*imate%$

a 1"5 secon's

"1"1"""2""21"""During a +rogramme' startu+ if an ignitor s+ark is -isib%ebut no f%ame a++ears t#e o+erator s#ou%' sus+ect

c t#e +i%ot manua% fue% -a%-e is c%ose'

"1"1"""2""21"""Af a s#ut'o&n occurs 'uring norma% firing of a boi%er an' t#esteam +ressure is be%o& t#e norma% cutout -a%ue9 t#e +rob%emcou%' be

a t#e sensing %ine to t#e combustion air +ro-ing s&itc# #as broken

"1"1"""2""21"""A

n a boi%er &it# #ig#%o& fire contro%9 if t#e 'am+er+ositioning s&itc# is in t#e &rong +osition

a t#e 'am+er motor ma$ not o+erate

Intro!u"tion to Pro"ess Computer #ppli"ations

49


50/160

"1"1"""2""21"""BT#e main function of a mainframe com+uter s$stem is to

b ra+i'%$ +rocess %arge amounts of 'ata

"1"1"""2""21"""AA t$+ica% use of a mainframe com+uter s$stem in a +rocess&ou%' be

a t#e o+eration of a mo'u%ating contro% -a%-e

"1"1"""2""21"""E!#aring an' transferring information bet&een com+uters isterme'

e net&orking

"1"1"""2""21"""DA mu%ti+%e*ing seuence ma$ be re+eate' as #ig# as' four times +er secon'

"1"1"""2""21"""Bom+uter >soft ke$ing> is

b 'one to make t#e com+uter uicker an' easier to use

"1"1"""2""21"""A 'igita% in+ut com+uter is +rotecte' from #armfu% -o%tagesb$ means of

c iso%ating circuits

"1"1"""2""21"""BTransmitters ic# transmit 'igita% co'es 'irect%$ to acom+uter are kno&n as

b smart transmitters

"1"1"""2""21"""ET#e common stan'ar' contro% mo'es for a +%ant contro% s$stemare

e 'eri-ati-e9 +ro+ortiona%9 an' integra%

"1"1"""2""21"""A

n+uts for %ogic an' su+er-isor$ com+uter functions aremain%$

a b$ s&itc# contacts

"1"1"""2""21"""Dom+uter >Run Time Tota%s> are common%$ use'

' for maintenance management

50


51/160

*atertube an! Tubular Heating %oilers

"1"1"""2""21"""DT#e combustion c#amber of a ser+entine tube &atertube boi%er

is

' %ocate' be%o& t#e tube

"1"1"""2""21"""Dne of t#e reasons t#at in'ustria% t$+e &atertube boi%ers arese%'om se%ecte' for %o& +ressure #eating +%ants is

' #ig# cost

"1"1"""2""21"""A membrane &ater&a%%

c #as meta% connecting t#e tubes

"1"1"""2""21"""E8#at %imits t#e #eig#t of a +ackage' boi%er is

e trans+ortation reuirements

"1"1"""2""21"""T#e use of bent tube boi%er 'esigns a%%o&s t#e furnace &a%%to be %ine' &it# tubes9 t#ereb$ e*+osing more of t#e #eatingsurface to

c ra'iant #eat

"1"1"""2""21"""DT#e bent tube boi%er 'esign a%%o&s t#e tubes to be attac#e'ra'ia%%$ on t#e outsi'e of t#e

' s#e%% or 'rum

"1"1"""2""21"""n a %o& +ressure ser+entine tube &atertube boi%er9 t#eser+entine tubes are attac#e' to u++er an' %o&er #ea'ers &it#KKKKKKKKKK connections.

c t#rea'e'

"1"1"""2""21"""BT#e furnace &a%%s in a benttube &atertube boi%er are forme'b$ &ater fi%%e' tubes an' t#ese &a%%s are ca%%e'

b &ater &a%%s

"1"1"""2""21"""DA reason for +referring co++er tubing in a tubu%ar boi%er is' corrosion resistance

51


52/160

"1"1"""2""21"""BAn initia% +rob%em &it# t#e tubu%ar boi%er being use' as asteam unit &as

b 'isso%-e' im+urities forming sca%e on t#e tube

"1"1"""2""21"""EAn a'-antage of a +ackage' %o& +ressure tubu%ar or &atertubeboi%er ise safet$ 'ue to t#e %o& -o%ume of &ater it contains

"1"1"""2""21"""Dne of t#e a'-antages of t#e %o& +ressure ser+entine tube&atertube boi%ers is

' ease of re+%acement of 'efecti-e tubes

"1"1"""2""21"""

ne of t#e a'-antages of t#e %o& +ressure ser+entine&atertube boi%er isc -irtua%%$ e%iminates e*+ansion an' contraction stresses

"1"1"""2""21"""AA reason for +referring co++er tubing in a tubu%ar boi%er is

a faster #eat transfer rate

"1"1"""2""21"""A +ackage' tubu%ar steam boi%er often #as a stee% s#eat#ingin front of t#e &ater&a%% tubes 'ue to

c t#e erosi-e action of t#e f%ame

"1"1"""2""21"""An or'er to kee+ sa%t concentrations &it#in safe %imits t#e+ackage' tubu%ar steam boi%er uti%i@es

a an automatic b%o&'o&n

"1"1"""2""21"""BA 'isa'-antage of t#e &atertube or tubu%ar boi%er is

b &ater treatment monitoring

"1"1"""2""21"""AT#e co++er tube tubu%ar boi%er

a can be gas or oi% fire'

Cast'iron Se"tional an! Mo!ular %oilers

52


53/160


54/160

a effecti-eness of #eat transfer

"1"1"""2""21"""ETo +re-ent f%ue gases from esca+ing in a cast iron sectiona%boi%er9 t#e s+aces bet&een t#e sections are sea%e' &it# #ig#tem+erature

e asbestos ro+e

"1"1"""2""21"""


55/160

c #as t#e furnace surroun'e' b$ &ater

"1"1"""2""21"""ET#e forerunner of t#e mo'ern +ackage' firetube boi%er &ast#ee !cotc# arine boi%er

"1"1"""2""21"""Anitia%%$ t#e firetube boi%er &as not u+ to manufacturinge*+ectations because

a too man$ eui+ment su++%iers &ere in-o%-e' in its manufacture

"1"1"""2""21"""A!ma%%er firetube boi%ers are %o& cost an'

a #a-e sim+%e rugge' construction

"1"1"""2""21"""A8#en a +ackage' firetube boi%er is use' as a +o&er boi%errat#er t#an a #eating unit

a it &i%% #a-e a muc# stronger 'esign

"1"1"""2""21"""E

T#e steam +ressure must not e*cee' 1"3 kafor a boi%erto be consi'ere' a #eating boi%er.

"1"1"""2""21"""DT#e tem+erature of a boi%er must not e*cee' 121

'egrees e%sius or t#e +ressure e*cee' 113" kPa for it to beconsi'ere' a #eating boi%er.

"1"1"""2""21"""BTo maintain #ig# gas -e%ocities t#roug#out a%% gas +asses ina four+ass firetube boi%er9 t#e crosssectiona% area of eac#succee'ing +ass is

b 'ecrease'

"1"1"""2""21"""A firetube boi%er common%$ use' for #ot &ater #eating s$stemsin resi'ences an' sma%% a+artments is t#ec stee% +%ate -ertica% unit

"1"1"""2""21"""EA stee% +%ate -ertica% firetube unit is 'i-i'e' into t&osections an' t#e u++er +art is often ca%%e' t#e

e #eat e*c#anger

"1"1"""2""21"""E8#en t#e #ot combustion gases tra-e% t#roug# boi%er tubes ic#

55


56/160

are surroun'e' b$ t#e boi%er &ater9 t#e boi%er is ca%%e' a

e firetube boi%er

"1"1"""2""21"""Package' firetube boi%ers

c reuire re%ati-e%$ sma%% bui%'ing -o%umes

"1"1"""2""21"""D8#en a +ackage' firetube boi%er is use' as a #ot &ater unit

' force' circu%ation is reuire'

"1"1"""2""21"""DT#e a'-antages of a +ackage' boi%er are(

1. %o&er freig#t costs because of %ess #an'%ing 2. %o&er initia% cost because t#e$ are mass +ro'uce' 3. ua%it$ contro% is easier to im+%ement

4. t#e boi%ers can be factor$ teste' before being sent to t#e customer 5. it reuires %itt%e time to +ut t#e unit into o+eration at t#e +%ant site

"1"1"""2""21"""T#e c#ief a'-antage of a +ackage' boi%er is t#at it can be

c mass +ro'uce'

"1"1"""2""21"""ne of t#e a'-antages of t#e firetube boi%er o-er t#e&atertube an' tubu%ar boi%er is in t#ec &ater treatment area

"1"1"""2""21"""AT#e a'-antage of a -ertica% firetube boi%er is t#at itreuires

a -er$ %itt%e f%oor s+ace

il %urners for Heating %oilers

"1"1"""2""21"""DT#e re'ucing of oi% into -er$ sma%% +artic%es is terme'

' atomi@ation

"1"1"""2""21"""BBefore atomi@ation can occur9 #ea-$ oi%s are #eate' toa++ro*imate%$

b 5 'egrees

"1"1"""2""21"""EAn air atomi@ing burner uti%i@es an air +ressure of

56


57/160

a++ro*imate%$

e 1"" kPa

"1"1"""2""21"""DAn air atomi@ing com+ressor is usua%%$' a +ositi-e 'is+%acement t$+e

"1"1"""2""21"""AT#e ca+acit$ of a constant ca+acit$ mec#anica% atomi@er is afunction of

a orifice si@e

"1"1"""2""21"""BA mo'u%ating +ressure atomi@er #as its return oi% f%o&regu%ate' b$

b a mo'u%ating -a%-e in t#e return %ine

"1"1"""2""21"""ATo ic# of t#e fo%%o&ing oi% burners is t#e oi% su++%ie' un'er#ig# +ressure;

a mec#anica% atomi@ing burner

"1"1"""2""21"""8#en using mec#anica% fue% oi% atomi@ationc #ig# +um+ +ressure is reuire'

"1"1"""2""21"""Ai% burners can be 'i-i'e' into t#ree c%asses(

1. air an' steam atomi@ing burners 2. mec#anica% or +ressure atomi@ing burners 3. centrifuga% or rotar$ cu+ burners

"1"1"""2""21"""BT#e com+resse' air use' as atomi@ing air in t#e air atomi@ingoi% burner is a%so ca%%e'

b +rimar$ air

"1"1"""2""21"""BT#e t&o basic -arieties of mec#anica% atomi@ing oi% burnersare(

2. constant ca+acit$ burner 3. mo'u%ating burner

"1"1"""2""21"""DA mu%tiburner c%uster #as secon'ar$ an' tertiar$ no@@%esignite' b$

' t#e +rimar$ burner

57


58/160

"1"1"""2""21"""B8#en a greater t#an norma% amount of combustib%e mi*ture isignite' t#e resu%t ma$ be

b a +uffback

"1"1"""2""21"""A fue% fi%ter consists of

c t#ree main +arts

"1"1"""2""21"""DBurner %ig#t oi% su++%$ +ressure range is a++ro*imate%$' 55" to 7"" kPa

"1"1"""2""21"""BA re%ief -a%-e is +%ace' on t#e 'isc#arge of a fue% oi% +um+

b so burner 'esign +ressure is not e*cee'e'

"1"1"""2""21"""BA time 'e%a$ oi% -a%-e

b o+ens once ignition is -erifie'

"1"1"""2""21"""n or'er to +re-ent t#e +ossibi%it$ of a furnace e*+%osion itis im+ortant t#at t#e furnace is +urge' before t#eignitor is energi@e' an' fue% is su++%ie' to t#e burnerno@@%eMs.

"1"1"""2""21"""Enterme'iate an' #ig# fire burner no@@%es #a-e #ig#erca+acities t#an t#e +rimar$ burner no@@%ee to a%%o& better boi%er &armu+s

"1"1"""2""21"""Ai% f%o& rate to a mo'u%ating burner is regu%ate' b$

a a return %ine mo'u%ating -a%-e

"1"1"""2""21"""T#e minimum 'istance from furnace to oi% storage tank isc 2.1 m

"1"1"""2""21"""Ea*imum static +ressure in a fue% oi% %ine is a++ro*imate%$

e 7" kPa

Gas %urners for Heating %oilers

"1"1"""2""21"""

58


59/160

T#e main function of a gas burner is

c +ro-ision of fue% contact 2

"1"1"""2""21"""BAn atmos+#eric burner #as air entering aroun' t#e burneric# is terme'

b secon'ar$ air

"1"1"""2""21"""DT#e amount of +remi* air to an atmos+#eric burner s#ou%' be

' 3" to 4"

"1"1"""2""21"""AA refractor$ burner 'isa'-antage is

a #ig# initia% cost

"1"1"""2""21"""AA -er$ +o+u%ar +ackage' boi%er gas burner is t#e

a ring burner

"1"1"""2""21"""DAn atmos+#eric burner #ea' ic# is -er$ +o+u%ar on #eatingboi%ers is t#e

' rectangu%ar t$+e

"1"1"""2""21"""A8#en a gas fire' burner is burning fue% +ro+er%$

a it &i%% #a-e a b%ue f%ame &it# s#ort $e%%o& ti+s

"1"1"""2""21"""DCas burners for #eating boi%ers can be 'i-i'e' into t&ogenera% c%asses an' t#e$ are t#e

' +re an' after mi* burners

"1"1"""2""21"""BT#e Ienturi tube in t#e atmos+#eric burner mi*ing #ea' #as a

b gra'ua%%$ increasing crosssectiona% area

"1"1"""2""21"""ERectangu%ar burner #ea's are most common for use in #eatingboi%ers.

"1"1"""2""21"""B

59


60/160

ne of t#e a'-antages of t#e refractor$ Mgas burner is t#e

b gas an' air mi*ture is t#oroug#%$ +re#eate' before it enters t#e furnace

"1"1"""2""21"""DT#e +ur+ose of t#e 'ef%ector -anes in t#e centre of a ringMgas burner is to' +romote turbu%ence of t#e gas an' air mi*ture

"1"1"""2""21"""Ane of t#e a'-antages of using natura% gas as a fue% in aboi%er is

a t#at no storage s+ace is reuire'

"1"1"""2""21"""An intermittent +i%ot

c %ig#ts t#emainf%ame an' remains on &it# it

"1"1"""2""21"""T#e +i%ot burner for gas fire' #eating eui+ment can be(

3. intermittent 4. interru+te' 5. automatic

"1"1"""2""21"""E

T#e continuous+i%ot is most often use' on sma%% boi%ers.

"1"1"""2""21"""D6arge ca+acit$ burners

' s#ou%' #a-e minimum f%o& on ignition

"1"1"""2""21"""BA #$'ramotor -a%-e

b #e%+s to +re-ent +uffbacks

"1"1"""2""21"""AA so%enoi' t$+e fue% -a%-e

a is #e%' c%ose' b$ fue% +ressure"1"1"""2""21"""Bf t#e +o&er is cut off to an automatic gas -a%-e9 t#e -a%-e&i%% be

b c%ose' imme'iate%$

"1"1"""2""21"""A

60


61/160

T#e a'-antage of a motori@e' M#$'ramotor gas -a%-e is t#at

t#e -a%-e o+ens s%o&%$t#us +re-enting >furnace +uff>.

%asi" (ittings for $ow'pressure Steam %oilers I

"1"1"""2""21"""A function of a Bour'on tube gage #airs+ring is

c e%iminate back%as#

"1"1"""2""21"""AAn 6P steam +ressure gage range s#a%% be bet&een

a 21" an' 42" kPa

"1"1"""2""21"""EAn ins+ectors: test connection

e is not man'ator$ on 6P boi%ers

"1"1"""2""21"""D8#en insta%%ing a si+#on it

' s#ou%' be first fi%%e' &it# &ater

"1"1"""2""21"""BAn in'ication of a +ressure gage not +erforming +ro+er%$ is

b t#e nee'%e not returning to @ero on'e+ressuri@ing

"1"1"""2""21"""A8#en using a 'ea' &eig#t tester9 t#e effect of friction

a is re'uce' b$ rotating t#e +%atform

"1"1"""2""21"""DT#e &orking me'ium in t#e 'ea' &eig#t tester is

' me'ium &eig#t oi%"1"1"""2""21"""DAn essentia% fitting bet&een t#e boi%er an' t#esteam +ressure gage is

' a si+#on

"1"1"""2""21"""EA steam +ressure gauge is gra'uate' in

61


62/160

e ki%o+asca%s

"1"1"""2""21"""T#e +rime im+ortance of boi%er fittings are

c safet$

"1"1"""2""21"""AA%% boi%er fittings not +ro+er%$ or c%ear%$ i'entifie' s#ou%'be

a re?ecte'

"1"1"""2""21"""T#e +ur+ose of t#e test connection on a boi%er +ressure gaugeis to

c insta%% t#e boi%er ins+ector:s +ressure gauge"1"1"""2""21"""AAs t#e boi%er +ressure increases9 t#e bour'on tube of t#e+ressure gauge &i%%

a ten' to straig#ten

"1"1"""2""21"""ET#e crosssection of a Bour'on tube is genera%%$

e o-a%

"1"1"""2""21"""DAn essentia% fitting bet&een t#e boi%er an' t#e steam+ressure gauge is a

' si+#on

"1"1"""2""21"""T#e +ur+ose of t#e +i+e si+#on insta%%e' bet&een t#e boi%eran' t#e +ressure gauge is to +re-ent

c #ot steam from entering t#e gauge

"1"1"""2""21"""AAccor'ing to t#e A!E co'e9 t#e sca%e on t#e 'ia% of t#esteam gauge for a %o& +ressure steam #eating boi%er s#a%% begra'uate' to not %ess t#an

a 21" kPa

62


63/160

"1"1"""2""21"""BAccor'ing to t#e A!E co'e9 t#e sca%e on t#e 'ia% of t#esteam gauge for a %o& +ressure steam #eating boi%er s#a%% begra'uate' to not more t#an

b 42" kPa

"1"1"""2""21"""BAn 6P steam boi%er safet$ -a%-e s#a%% not be sma%%er t#an

b 12.7 mm

"1"1"""2""21"""Dn or'er to ensure a safet$ -a%-e seats +ro+er%$9 it uses

' gui'es an' bus#ings

"1"1"""2""21"""A

T#e force of t#e steam +ressure acting on t#e safet$ -a%-e'isc is a function of

a 'isc area

"1"1"""2""21"""T#e minimum b%o&'o&n of an 6P safet$ -a%-e is

c 14 kPa

"1"1"""2""21"""Po++ing +ressure of an 6P safet$ -a%-e ma$ be a'?uste'

c u+ to 5

"1"1"""2""21"""DT#e b%o&'o&n on a safet$ -a%-e is a'?uste' b$ turning t#e

' a'?usting ring

"1"1"""2""21"""8#at 'oes t#e boi%er ins+ector insta%% to +re-ent tam+ering &it#a safet$ -a%-e setting;

c a sea%

"1"1"""2""21"""ET#e %i+ on a safet$ -a%-e

e a%%o&s it to >+o+> o+en

"1"1"""2""21"""DA safet$ -a%-e on a steam #eating boi%er must not be sma%%er t#an

' 13 mm

63


64/160

"1"1"""2""21"""DAccor'ing to t#e A!E co'e9 steam #eating boi%ers s#a%% #a-eone or more safet$ -a%-es9 a'?uste' an' sea%e' to 'isc#argeat a +ressure not e*cee'ing 1"3 kPa.

"1"1"""2""21"""AAccor'ing to t#e A!E co'e9 t#e -a%-e seat 'iameter of t#esafet$ -a%-e on a steam #eating boi%er must not be sma%%ert#an

a 12.7 mm M1,2 in.

"1"1"""2""21"""EAccor'ing to t#e A!E co'e9 t#e -a%-e seat 'iameter of t#esafet$ -a%-e on a steam #eating boi%er must not be %argert#an

e 11" mm M4 1,2 in.

"1"1"""2""21"""Eor a steam #eating boi%er9 t#e safet$ -a%-e s#a%% be suc#t#at9 &it# t#e fue% burning eui+ment insta%%e' an' o+erate'at ma*imum ca+acit$9 t#e +ressure cannot rise more t#an34 kPa abo-e t#e ma*imum a%%o&ab%e &orking +ressureen a%% steam out%ets are c%ose'.

"1"1"""2""21"""DT#e safet$ -a%-e s#a%% be insta%%e' in KKKKKKKKKK +ositionan' %ocate' in t#e #ig#est +racticab%e +art of t#e boi%er+ro+er.

' a -ertica%

"1"1"""2""21"""An 6P safet$ -a%-e %e-er test s#ou%' be +erforme'

c mont#%$

"1"1"""2""21"""6P boi%er safet$ -a%-es can be re+aire'

c b$ a ua%ifie' boi%er o+erator after+ermission from t#eins+ector

"1"1"""2""21"""B

b increasing t#e boi%er +ressure unti% t#e -a%-eo+ens an' noting t#e +ressure on t#e +ressure gageen t#e -a%-e o+ene'

"1"1"""2""21"""B

64


65/160

Testing t#e safet$ -a%-e b$ means of t#e tr$ %e-er met#o'9 isconsi'ere' goo' +ractice en carrie' out on a

b mont#%$ basis

"1"1"""2""21"""

f a safet$ -a%-e %eaks after a tr$ %e-er test9 t#e o+erators#ou%'

c o+erate t#e tr$ %e-er se-era% times to b%o&a&a$ foreign materia%

"1"1"""2""21"""Df $ou foun' t#e safet$ -a%-e on $our #eating boi%er stuck in t#ec%ose' +osition i%e t#e boi%er &as in o+eration9 t#e best t#ingto 'o is

' s#ut 'o&n t#e boi%er an' re+air or re+%ace t#esafet$ -a%-e

%asi" (ittings for $ow'pressure Steam %oilers II

"1"1"""2""21"""6P steam boi%ers must be eui++e' &it# a marker in'icatingt#e

c %o&est +ermissib%e &ater %ine

"1"1"""2""21"""DA gage g%ass ma$ be surroun'e' b$ a number of t#in ro's

' to +rotect t#e g%ass from 'amage

"1"1"""2""21"""EQuickc%osing gage g%ass -a%-es

e reuire " 'egrees for fu%% tra-e%

"1"1"""2""21"""BA 'isa'-antage of a gage g%ass safet$s#utoff -a%-e is

b it reuires more maintenance

"1"1"""2""21"""D!#ou%' t#e steam %ine or &ater %ine to a gage g%ass become+%ugge' &it# s%u'ge

' t#e gage g%ass &i%% rea' #ig#

65


66/160

"1"1"""2""21"""B8ater co%umn su++%$ %ine crosses &i%%

b a%%o& for +i+ing c%eaning an' ins+ection

"1"1"""2""21"""B

Cage g%ass ru+ture ma$ be cause' b$

b a co%' 'raft

"1"1"""2""21"""D8#en gage g%ass nuts are %eaking

' t#e g%ass s#ou%' be iso%ate' an' 'e+ressuri@e'before tig#tening

"1"1"""2""21"""A8#en t#e &ater connection bet&een boi%er an' gage g%ass becomes+%ugge'9 t#e &ater %e-e% in t#e g%ass &i%% s#o& a %e-e% aftera i%e9 t#at is

a #ig#er t#an t#e %e-e% in t#e boi%er

"1"1"""2""21"""AT#e %o&est -isib%e +art of t#e &ater gauge g%ass s#a%% be at%east 25 mm abo-e t#e %o&est +ermissib%e &ater %e-e%recommen'e' b$ t#e manufacturer.

"1"1"""2""21"""DT#e A!E co'e states t#at eac# steam boi%er s#a%% #a-e one ormore &ater gauge g%asses attac#e' eit#er 'irect%$ to t#eboi%er or to a &ater co%umn b$ means of -a%-e fittings not%ess t#an 13 mm +i+e si@e.

"1"1"""2""21"""Bn a mu%ti+%e steam boi%er #eating s$stem9 a sto+ -a%-e mustbe +%ace' at eac# boi%er out%et to

b a%%o& boi%er iso%ation from t#e s$stem

"1"1"""2""21"""A

Boi%er out%et -a%-es are usua%%$

a gate -a%-es because of t#eir %o& resistance tof%o&

"1"1"""2""21"""BAn outsi'e scre& an' $oke -a%-e

66


67/160

b rea'i%$ s#o&s its o+erating +osition

"1"1"""2""21"""BT#e uick c%osing -a%-es on t#e &ater gauge reuires on%$a uarter of a turn of t#e -a%-e s+in'%e to c#ange t#e-a%-e from t#e fu%% o+en to t#e fu%% c%ose' +osition an' -ice

-ersa.

"1"1"""2""21"""DT#e fee'&ater +i+e9 before it enters t#e boi%er must befitte' &it# a c#eck -a%-e a'?acent to t#e boi%er.

"1"1"""2""21"""EA boi%er fee'&ater sto+ -a%-e

e is use' to iso%ate t#e fee'&ater %ine

"1"1"""2""21"""BA g%obe -a%-e s#ou%' be use' in t#e fee'&ater %ine

b ene-er it ma$ be use' for contro% +ur+oses

"1"1"""2""21"""BA sto+ -a%-e is fitte' bet&een t#e boi%er an' t#e fee' &ater c#eck-a%-e

b for iso%ation an' to +ro-i'e a +ositi-e s#utoff

"1"1"""2""21"""DBoi%er &ater foaming ma$ be t#e resu%t of

' #ig# TD!

"1"1"""2""21"""Boi%er b%o&'o&n %ines #a-e a s+ecific si@e range base' on

c boi%er ca+acit$

"1"1"""2""21"""BBoi%er b%o&'o&n +i+ing

b must be fu%% si@e to t#e +oint of 'isc#arge

"1"1"""2""21"""A steam boi%er is b%o&n 'o&n in or'er to

c 'isc#arge se'iment an' sca%e forming matterfrom t#e boi%er

67


68/160

"1"1"""2""21"""DT#e +ur+ose of t#e sma%% -ent -a%-e or cock %ocate' on to+of t#e s#e%% or on to+ of t#e &ater co%umn on most boi%ers is

' to a%%o& air to esca+e from t#e boi%er en

t#e boi%er is being fi%%e' &it# &ater

%asi" (ittings for Hot *ater %oilers

"1"1"""2""21"""A +ressure or a%titu'e gage for a #ot &ater boi%erc 'oes not reuire a si+#on

"1"1"""2""21"""A8#en a c%ose' e*+ansion tank is use' an' t#e s$stem is co%'

a t#e auto fi%% -a%-e &i%% maintain a s$stemminimum +ressure

"1"1"""2""21"""DAn a%titu'e gage on #ot &ater #eating boi%ers is use' to in'icate

' #eig#t of t#e #ig#est ra'iator in s$steme t#e #eig#t of t#e boi%er

"1"1"""2""21"""D!i+#on is not reuire' bet&een a +ressure or an a%titu'e

gauge an' a #ot &ater boi%er since t#ese boi%ers are

' fi%%e' &it# &ater

"1"1"""2""21"""BT#e %e-er #an'%e of t#e s#utoff cock bet&een a +ressure ora%titu'e gauge an' a #ot &ater boi%er s#ou%' be PARA66E6 tot#e +i+e in ic# it is %ocate' en t#e cock is o+en.

b +ara%%e%

"1"1"""2""21"""A

T#e sca%e on t#e 'ia% of a +ressure gauge s#ou%' be gra'uate'to not %ess t#an 1.5 times t#e ma*imum a%%o&ab%e&orking +ressure.

"1"1"""2""21"""ET#e 'ia% of a +ressure gauge on a #ot &ater boi%er in'icating! units can be gra'uate' in kPa

68


69/160

"1"1"""2""21"""E8#en t#e +ressure +ointer of a c%ose' s$stem rea's %o&er t#ant#e a%titu'e +ointer t#e

e s$stem reuires &ater

"1"1"""2""21"""DT#e tem+erature in'icator of a #ot &ater boi%er s#ou%'in'icate &ater tem+erature

' at t#e boi%er out%et

"1"1"""2""21"""Bn a +ressure tem+erature in'icator9 if t#e +ressure +ointerfa%%s be%o& t#e a%titu'e +ointer

b t#e s$stem is %o& on &ater

"1"1"""2""21"""A


70/160

"1"1"""2""21"""EA #ot &ater boi%er is +rotecte' from o-er +ressure b$ means of

a a safet$ +o+ -a%-eb a #ig# %imit +ressure contro%c an e*+ansion -a%-e' an air re%ease -a%-e

e a safet$ re%ief -a%-e

"1"1"""2""21"""AA!E !ection I9 states t#at eac# #ot &ater #eating boi%ers#a%% #a-e at %east one officia%%$ rate' +ressure re%ief-a%-e set to re%ie-e at or be%o& t#e ma*imum a%%o&ab%e&orking +ressure of t#e boi%er.

"1"1"""2""21"""E


71/160

b t#e +ressure bui%'u+ o+ens t#e safet$ re%ief-a%-e

"1"1"""2""21"""

An e*+ansion tank is use' to

c a%%o& for t#e e*+ansion of t#e &ater

"1"1"""2""21"""DT#e #ea' of &ater in t#e #ot &ater #eating s$stem em+%o$ingan o+en t$+e of e*+ansion is referre' to t#e -ertica%'istance from t#e gauge of t#e boi%er to t#e %e-e% in t#ee*+ansion tank9 ic# is consi'ere' t#e #ig#est %e-e% of t#e&ater in t#e s$stem.

' e*+ansion tank

"1"1"""2""21"""An automatic fi%% -a%-e

c is not man'ator$

"1"1"""2""21"""AA c%ose' e*+ansion tank is usua%%$ eui++e' &it#

a a gage g%ass

Hot *ater Steam Heating %oiler perations

"1"1"""2""21"""BBefore starting u+ a ne& boi%er or one t#at #as been out ofser-ice t#e fo%%o&ing must be ensure'

b t#e boi%er #as a -a%i' ins+ection certificate

"1"1"""2""21"""Dt is -er$ im+ortant t#at boi%ers s#ou%' be

' &arme' u+ s%o&%$ to +re-ent t#erma% s#ock"1"1"""2""21"""A8#en cutting in an a''itiona% boi%er into t#e #eating s$stem

a t#e sto+ -a%-es in t#e su++%$ an' return %inesare bot# c%ose'

"1"1"""2""21"""D

71


72/160

ne of t#e most im+ortant +oints t#at s#ou%' be obser-e'before a ne& boi%er is starte' an' +ut into continuouso+eration is to

' make sure t#e ins+ection certificate is -a%i'

"1"1"""2""21"""D8#en +re+aring a boi%er for startu+ an' t#e boi%er iseui++e' &it# a mo'u%ating combustion contro%9 it is best to

' set t#e manua%auto s&itc# to >manua%> an' sett#e f%ame contro% s&itc# in t#e %o&est +osition

"1"1"""2""21"""Bf t#e %o&&ater fue% cutoff an',or t#e #ig# %imit contro%are eui++e' &it# a tri+out 'e-ice on a boi%er9 it isrecommen'e' as +art of t#e startu+ +re+aration to

b +us# t#e reset button to assure t#at t#es&itc#es are c%ose'

"1"1"""2""21"""Dn #ot &ater boi%er o+eration t#e ma*imum o+eratingtem+erature s#ou%' ne-er e*cee'

d) 121 degrees !

"1"1"""2""21"""T#e +ressure re%ief -a%-e on a #ot &ater #eating boi%er

s#ou%' be set

c 25 abo-e o+erating +ressure

"1"1"""2""21"""A gra'ua% increase in stack tem+erature is an in'ication of

c unc%ean #eating surfaces

"1"1"""2""21"""D

T#e 'isc#arge +ressure of steam #eating +ressure re%ief-a%-es s#ou%' ne-er e*cee'

' 1"3 kPa,15 +si

"1"1"""2""21"""A


73/160

a 'ai%$

"1"1"""2""21"""BT#e ma*imum +ressure of a %o& +ressure steam #eating boi%er is

b 1"3 kPa, 15 +si"1"1"""2""21"""DT#e ma*imum o+erating tem+erature of a #ot &ater #eatingboi%er is

' 121 'egrees e%sius

"1"1"""2""21"""E!#ou%' an$ abnorma% con'ition occur 'uring %ig#toff or t#etem+erature bui%'ingu+ +erio'

a continue to run t#e boi%er but re'uce t#e steam an' fue%

e s#ut 'o&n t#e boi%er imme'iate%$ an' c%ose t#esto+ -a%-es in t#e fue% %ines

"1"1"""2""21"""T#ere are t&o con'itions t#at ma$ occur 'uring t#e &arm u++erio' ic# ma$ seem to be abnorma% to t#e o+erator but &i%%'isa++ear after t#e boi%er #eats u+. T#ese con'itions are

c s%ig#t smoking an' con'ensation

"1"1"""2""21"""B

During t#e &armu+ +erio' of a #eating boi%er t#emain burnergoes out. T#e o+erator s#ou%'

b s#ut 'o&n t#e boi%er9 c%ose t#e fue% -a%-es9an' 'etermine t#e cause of t#e +rob%em

"1"1"""2""21"""ET#erma% s#ock to boi%ers can be re'uce' b$

a &arming u+ boi%ers s%o&%$b kee+ing t#e boi%er free of sca%e bui%'u+

c co-ering t#e tube s#eets &it# refractor$' not a%%o&ing fu%% f%o& of co%' &ater into a&arm #ot &ater boi%ere a%% of t#e abo-e

"1"1"""2""21"""BT#e most im+ortant ru%e in safe o+eration of a steam #eatingboi%er is

73


74/160

b kee+ t#e &ater %e-e% in t#e boi%er at t#e+ro+er %e-e%

"1"1"""2""21"""BTo re'uce t#e effects of une-en e*+ansion an' t#erma% s#ock

an' to +rotect a boi%er against 'amage 'uring startu+9 one oft#e +recautions t#at s#ou%' be taken is

b a%&a$s &arm u+ t#e boi%er s%o&%$

"1"1"""2""21"""Dt is recommen'e' t#at t#e 'ifferentia% bet&een t#e safet$re%ief -a%-e set +ressure an' t#e o+erating +ressure of a #ot&ater boi%er be ke+t to a minimum of H kPa M1" +si or25 of t#e re%ief -a%-e setting.

"1"1"""2""21"""A!moking con'itions 'uring t#e o+eration of a boi%er can because' b$

a im+ro+er air,fue% ratio

Steam Heating E+uipment

"1"1"""2""21"""nit #eaters 'iffer from con-ectors in t#at t#e$ use b%o&ersto increase #eat transfer.

c b%o&ers

"1"1"""2""21"""Aon-ectors use meta% fins to increase #eat transfer.

a meta% fins

"1"1"""2""21"""Ra'iators can be c%assifie' as

c &a%%#ung9 f%oor9 %eg%ess9 an' &in'o&

"1"1"""2""21"""n fin coi% t$+e #eaters9 in'i-i'ua% room tem+erature iscontro%%e' b$

c 'am+ers

"1"1"""2""21"""Dnit -enti%ators use

74


75/160

' a mi*ture of insi'e an' outsi'e air

"1"1"""2""21"""DT#e 'ifference bet&een a con-ector an' a ra'iator is

' t#at one is ma'e of cast iron an' t#e ot#er ofstee% or co++er

"1"1"""2""21"""A6arge areas suc# as &are#ouses9 are usua%%$ #eate' &it#

a unit #eaters

"1"1"""2""21"""AAir can be remo-e' from steam #eating s$stems b$

a air -ents"1"1"""2""21"""EA ra'iator -a%-e is use' to contro% t#e amount of

e steam entering t#e ra'iator

"1"1"""2""21"""EA ra'iator tra+ is a 'e-ice t#at is use' to

e a%%o& on%$ &ater to %ea-e t#e ra'iator

"1"1"""2""21"""T#e -acuum +um+ +erforms t#e fo%%o&ing function(

c returns t#e con'ensate M&ater back to t#eboi%er

"1"1"""2""21"""AT#e %e-e% in t#e con'ensate recei-er is automatica%%$contro%%e' b$ a

a f%oat s&itc#

"1"1"""2""21"""

T#e +ur+ose of a ra'iator tra+ is to

c 'rain con'ensate from t#e ra'iator

"1"1"""2""21"""BAir -ents are use' to

75


76/160

b e*+e% t#e air from #eating s$stems

"1"1"""2""21"""ET#e +ur+ose of a ra'iator tra+ is to

e +ass con'ensate an' retain steam in t#era'iator

Steam Heating Systems

"1"1"""2""21"""T#e +i+ing an' #eating units of a steam #eating s$stem mustbe so arrange' t#at

c steam can f%o& free%$ to a%% #eating units

"1"1"""2""21"""Bn a gra-it$ return s$stem t#e boi%er s#ou%' be +%ace'

b &e%% be%o& t#e %o&est ra'iator

"1"1"""2""21"""T#e


77/160

e -a%-es an' tra+s

"1"1"""2""21"""Dinne' con-ectors s#ou%' be ke+t free of

' 'ust

"1"1"""2""21"""B!%o& or insufficient #eat t#roug#out a bui%'ing #eate' b$steam can be cause' b$

b too %o& a firing rate

"1"1"""2""21"""A!%o& or insufficient #eat in one or more rooms in a steam#eate' bui%'ing can be cause' b$ a

a fau%t$ steam tra+

Hot *ater Heating Systems

"1"1"""2""21"""T#e ma*imum tem+erature of &ater in a gravit" #ot &aters$stem is F7

"1"1"""2""21"""Bn a force' circu%ation s$stem t#e e*+ansion tanka%%o&s t#e s$stem to o+erate at

b a +ressure &e%% abo-e atmos+#eric +ressure

"1"1"""2""21"""EA force' #ot &ater circu%ating s$stem can be c%assifie' ast#e fo%%o&ing t$+e(

a %oo+ s$stemb one +i+e s$stem

c t&o +i+e 'irect return s$stem' t&o +i+e re-erse return s$steme a%% of t#e abo-e

"1"1"""2""21"""An a one +i+e #ot &ater s$stem t#e fitting t#at 'irects t#e&ater to eac# con-erter is ca%%e' t#e

77


78/160

a 'i-erter

"1"1"""2""21"""n a ra'iant #eating s$stem t#e ma*imum surface tem+eratureis

c 3" 'egrees

"1"1"""2""21"""An ra'iant #eating s$stem c#anges are

a 'ifficu%t to make

"1"1"""2""21"""EAutomatic sno& me%ting s$stems can use

a #ot &ater an' antifree@e mi*e'

b e%ectric resistance #eatingc infrare' %am+s mounte' abo-e si'e&a%ks an'ram+s' #ot &ater an' et#$%ene g%$co% mi*e'e a%% of t#e abo-e

"1"1"""2""21"""!no& me%ting s$stems are usua%%$ fi%%e' &it#

c et#$%ene g%$co% an' &ater

"1"1"""2""21"""AA'-antages of t#e force' circu%ation #ot &ater #eatings$stems are

a re'uction in +i+e si@e an' greater #eatstorage ca+acit$

"1"1"""2""21"""BA #ot &ater boi%er of t#e same out+ut is

b sma%%er t#an a steam boi%er

"1"1"""2""21"""Bn a #ot &ater s$stem com+are' to a steam #eating s$stem9 ift#ere is a %eak 'amage &i%%

b be greater in t#e #ot &ater s$stem

"1"1"""2""21"""E8#ic# of t#e fo%%o&ing use a boi%er in t#e s$stem;

78


79/160

1. steam #eating 3. steam to #ot &ater s$stem 4. #ot &ater #eating

- #ot $ater #eating "stem &'uipment and (peration

"1"1"""2""21"""BDi-erter fittings are use' in t#e su++%$ %ines to #eatingunits

en a #ig#er #eating out+ut is reuire' fromt#e #eating unit

"1"1"""2""21"""AAn air se+arator s#ou%' a%&a$s be insta%%e' in

a a #ori@onta% +i+e

"1"1"""2""21"""DT#e air remo-e' b$ t#e air se+arator is -ente' to t#e

' e*+ansion tank

"1"1"""2""21"""E

e ba%ancing -a%-e is use'

"1"1"""2""21"""DT#e tem+erature contro% on a steam to hot water converter9 contro%s

' t#e steam contro% -a%-e

Hot *ater Heating System E+uipment an! peration

"1"1"""2""21"""E*cessi-e +ressure bui%'u+ 'ue to a rise in tem+erature an't#e resu%ting e*+ansion of t#e &ater in t#e s$stem is+re-ente' b$ t#e use of

c an e*+ansion tank

"1"1"""2""21"""ATo +re-ent corrosion in t#e e*+ansion tank it is sometimesfi%%e' &it#

a nitrogen

79


80/160

"1"1"""2""21"""Em+ro+er %ocation of t#e circu%ating +um+ an' e*+ansion tankcan cause

a t#e circu%ating +um+ to ca-itate

b some +oints in t#e s$stem to be un'er negati-e+ressurec air to be 'ra&n into t#e s$stem' -a+our bubb%es to form in t#e circu%ating +um+e a%% of t#e abo-e

"1"1"""2""21"""AT#e e*+ansion tank is norma%%$ attac#e' to t#e

a boi%er or t#e #ot &ater su++%$ %ine near t#eboi%er

"1"1"""2""21"""DT#e minimum rea'ing on an a%titu'e gage of a boi%er in a%arge +%ant is from t#e to+ of t#e boi%er to t#e #ig#est+oint in t#e s$stem +%us 1.2m

"1"1"""2""21"""BT#e +ur+ose of a +ressure re'ucing -a%-e is to

b automatica%%$ re'uce +ressure an' maintain it

"1"1"""2""21"""B8#at t$+e of boi%er &ou%' $ou e*+ect to fin' in a #ot &aters$stem9 incor+orating a converter;

b steam boi%er

*arm #ir Heating System E+uipment

"1"1"""2""21"""Bn a &arm air #eating s$stem t#e co%' air return registersare %ocate'

b in interior %ocations

"1"1"""2""21"""AT#e ma?or 'isa'-antage of an e%ectric resistance coi% furnacefor &arm air #eating is

a t#e #ig# cost of e%ectricit$

80


81/160

"1"1"""2""21"""E6o&bo$ furnaces are ?ust o-er 1.2 m in #eig#t

"1"1"""2""21"""T#e a'-antage of #a-ing 'uct furnaces instea' of a %argecentra% furnace is

c better contro% of #eat in eac# @one of t#ebui%'ing

1"1"""2""21"""T#e +o&er su++%$ for an e%ectric resistance coi% furnace is

c 24" I

"1"1"""2""21"""An a fincoi% #eat e*c#anger t#e +rimar$ source of #eat for

t#e e*c#anger is

a steam or #ot &ater

"1"1"""2""21"""DA t$+e of directl" fireds+ace #eater is

a a unit #eaterb a f%oor furnacec a &a%% furnace

"1"1"""2""21"""B


82/160


83/160

a carbon mono*i'e cou%'

4b condensed qa

Documents