valves ppt.pptx

7/26/2019 Valves PPT.pptx

1/87

September2012

Control Valves&

On-Of Valves

By Baishakhi Bhattacharyya


2/87

IN!"Defnition : ValveDefnition : Control ValvesParts o Control ValvesDefnition : On-O ValvesNeed and Application o On-o valveTypes o Valve

Globe ValveBtter!y ValveBall ValveGate Valve"ccentric #otary pl$

C%aracteristic O Control ValvesActator

Accessories&ea'a$eCavitation ( )las%in$ and t%eir *iti$ationNoise and Noise #edction+o, to *a'e valves fre-sae".D Tri$$ersPeror*ance TestsPartial .tro'e test.tandards #elevant to Control Valves.tandards #elevant to On-O ValvesTest and Certifcation #elevant to Control ValvesTest and Certifcation #elevant to On-o ValvesControl valve si/in$


3/87

What is a Valve?

A valve is nothing but a restriction. A valveis a device that regulates, directs or controls

the flow of a fluid (gases, liquids, fluidized solids, or slurries) by oening, closing, or

artially obstructing various assageways.

V#$V!

Control valve On-of valve%otor Operate

valve

A !ontrol valve is a

restriction which is

caable of being"odulated in a conduit

that contains a flowing

fluid

An #$%#&&'shut down

valve (also referred to as

"ergency shutdownvalve, V, *, or

*V) is an actuated

valve designed to sto

the flow of a fluid

+otor #erated valve is a valve

where the Actuator art is

relaced by a "otor. +#V arenor"ally used for -arger

rocess lines where the

neu"atic ressure is not

enough to rovide required

torque Valves "ove"ent.


4/87

CON'(O$ V#$V!

he "ost co""on final control ele"ent in the rocess

control industries is the control valve.A !ontrol valve is a restriction which is caable of being

"odulated in a conduit that contains a flowing fluid.

!ontrol valves are co"rised of two "a/or arts0

the valve body, which contains all the "echanical

co"onents necessary to influence fluid flow1 and the

valve actuator, which rovides the "echanicalower necessary to "ove the co"onents within the

valve body.

2A 34.54 defined control valve as a ower oerated

device which "odifies the fluid flow rate in a rocess

control syste".

2t consists of a valve connected to an actuator"echanis" that is caable of changing the osition of a

flow controlling ele"ent in the valve in resonse to a

signal fro" a controlling syste".ingle%seat globe valve


5/87

PAR

TS

OF

CONT

ROL

V

ALV

E


6/87

Valve Body-The main pressure boundary of the valve that also provides the pipe connecting ends and thefluid flow passageway, and supports the valve trim.

BonnetAssembly-The portion of the valve that contains the packing box and stem seal and also may guidethe stem. t may also provide for the attachment of the actuator to the valve body. Typical bonnets are bolted,threaded, welded, pressure-sealed, or integral with the body.

Trim-The internal components of a valve that modulate the flow of the controlled fluid. !n a globe valvetypically, it would include plug, seat ring, cage, stem"

Valve#lug-The movable part of the valve that is positioned in the flow path to modulate the rate of flowthrough the valve.

$uide Bushing-The bushings fitted into the body, bonnet, bottom flange to guide the plug%s post.

&age-A part of a valve trim, in a globe or angle body, that surrounds the closure member and whose flowpassages may provide flow characteri'ation and(or a seating surface. t may also provide stability, guiding,balance, and alignment.

)eat*ing-A part of the valve body assembly that provides a seating surface for the closure member and mayprovide part of the flow control orifice.

)eat-The line of contact between the closure member and its mating surface that establishes valve shutoff.

)tem&onnector-The device that connects the actuator stem to the valve stem.

+oke - The structure that rigidly connects the actuator power unit to the valve.

Actuator- The purpose of a actuator is to provide the motive force to operate a valve mechanism.

#ositioner- a positioner is a device attached to an actuator that receives an electronic or pneumatic signalfrom a controller and compares that signal to the actuators position. f the signal and the actuator positiondiffer, the positioner sends the necessary power, usually through compressed air to move the actuator untilthe correct position is reached.


7/87

!S Operate)ON-O**V#$V!S

#n ON-O**)s%t do,n valve+also re,erre to as "*er$encys%tdo,n valve ".V ".D or".DV. is an act/ate valveesine to stop the o o, aha3aro/s /i or e4ternal

hyrocarbons +ases. /pon theetection o, a anero/s event5

!S)!SV valves provies e,enseaainst process miscreations5

!S ) !SV valves are connecte

to 6rorammable $oic Controller+6$C. an toether ith sensors,orm the Sa,ety $oop5

'hey enerally have a 'a Namestartin as "V or "V5


8/87

N!! #N #66$IC#'ION

'he lack o, sprin ret/rn capabilities on theiferent electric act/ator esins on the marketan its epenence on the s/pply so/rce tooperate an react to any iven sit/ation kno

makes the /sers v/lnerable to anero/ssit/ations an potential environmentalcatastrophes5

#lso ith toay7s environmental stanars an

re8/ire practices the nee to have !Scapabilities becomes prevalent an chanes theoperational ,/nction o, sectionin valves5


9/87

Nee & #pplication +Cont5.

'his provies protection aainst possibleharm to people e8/ipment or theenvironment5

Sh/ton valves ,orm part o, a Sa,ety

instr/mente system +SIS.5 9henever sensors ienti,y an abnormalanero/s process sit/ation the 6$Cisconnects the poer to !S solenoi valvean the valve oes to esire ,ail sa,e moe

by means o, sprin ,orce +*ail Close)*ailOpen.5

'he process o, proviin a/tomate sa,etyprotection /pon the etection o, a ha3aro/sevent is calle */nctional Sa,et 5


10/87

VA-V

6-#7 789&-: 7A--

2$6-

A*

*2A;9A6+

*#87-

A*A$6- < WA: 6+$* ' V%$#!; &8-- 7#9

+2=2$6*2V92$6

6A

T+#) / VA0V)

!!$92!

9#A9: -86


11/87

1a2orly the following kind of valves are used for &ontrol valves3

-$lobe

-Butterfly

-ccentric *otary #lug

-)egmented ( V-4otch Ball

1a2orly the following kind of valves are used for 4(// purposes

-Ball Valve

-Butterfly Valves

-$ate Valves


12/87

G&OB" VA&V"

6lobe valves are na"ed for their sherical body shae

with the two halves of the body being searated by an

internal baffle.

$lobe valves restrict the flow of fluid by altering the

distance between a movable plug and a stationary

seat.

When the lug is fitted into the seat, it stos the flow of

water. he lug can be left in any osition fro"

co"letely closed, to co"letely oen, deending on

the required flow of fluid.

$0B VA0V


13/87

)i'e0

> to >@1 higher size available on request.

Application0

he globe valve design is one of the "ost oular valve designs

used in throttling service.

o control large range of rocess ara"eters, secially in

etroche"ical, che"ical, fertilizer, oil and gas, ower, and other

rocess lants.

6lobe valves are frequently used for control alications because

of their suitability for throttling flow and the ease with which they

can be given a secific characteristic, relating valve oening to

flow.

!ontrol Valve 7ody

$0B VA0V


14/87

Sinle seate lobe valve

/low through a single seat

ingle%seated valves are the "ost widely used of the

globe body atterns.

here are good reasons for this0

;igh flow caacity

ight shut off

;igh rangeability

hey are available in a wide variety of

configurations, including secial%urose tri"s.

hey are available with wide range of

interchangeable tri" size.

hey have good seating shut%off caability, are less

sub/ect to vibration due to reduced lug "ass, and

are generally easy to "aintain.

/eatures0


15/87

/eatures0;igh flow caacityight shut off;igh rangeability. Valve flow rangeability, is the ratio of "aBi"u" rated flow to "ini"u"

controllable flow. he governing ara"eter is 9ated !v.;igher urndown, is the ratio between the valveCs "aBi"u" and "ini"u" controllable flow

rate at stated oerating ressures.Various tye of tri" e.g. contour, single stage, "ulti stage low noise, anti%cavitation tri"s, etc.Wide range of interchangeable tri" size.Available characteristics % DuicE oening, -inear F qual ercentage. he valve tri" consists

of the internal arts contained within the body and wetted by the rocess fluid. he "ain

co"onents are the lug and ste" and the seat rings.'he trim esin also serves to

etermine the inherent o characteristics o, the valve5

Valve plug shapes to produce the three

common flow characteristics:

equal percentage, linear, and quick opening.


16/87

APP&0CAT0ON: #nle valves are typically /se in hih press/re rop

applications an ,or erosive service here impinement o,soli particles is to be avoie5 #t hih press/re rops thevelocity o/l be very hih there,ore epenin on act/alonstream velocities these applications can re8/ire alarer pipe si3e than the valve5

9here process /i contains soli particles5

Corrosive or hih visco/s /i hich shall solii,y at roomtemperat/re beca/se the onars o/tp/t port oesnot allo the solii;e material to stay insie valve boy5

Angle valve

Angle valve

Typical )eatres:

12 +i$% )lo, Capacity

32 Ti$%t .%t-o


17/87

Three-way valvesare another for" of secialized globe valve body configuration that servetwo basic services0

>. +iBing service for the co"bination of two fluid strea"s assing to a co""on outlet ort.G. *iverting service for searating a co""on inlet ort into two outlet orts.

hree way valves are ideal for "iBing two searate flows by having two inlets and oneoutlet, or dividing a flow into two roortional arts by having one co""on inlet and twooutlets.

< Way valve


18/87

7utterfly valve

he rotary valves such as butterfly, ball, and lug valves were once considered to be only on'off valves. 2n recent decades

the rotary valves in general and the butterfly design in articular have been used "ore and "ore as throttling control

valves.

A*VA$A60 9elative to the traditional globe control valve, the butterfly valves have the advantages of lower cost and

weight, two to three ti"es the flow caacity of globe valves fire%safe designs, tight shut%off and low ste" leaEage. -ittle

resistance to flow (allows s"ooth flow).

#ti"al for auto"ated oeration with a low oerating torque and H5 degrees oerating angle.

*2A*VA$A60 When used for throttling service, so"e of their disadvantages are a direct consequence of the above

advantages. heir high%caacity design results in either using oversized valves or having s"all valves "ounted in large

ies. 2f s"all valves are used, this "eans substantial waste of u"ing energy caused by the reducer ressure dros.

The vane positions of butterfly valve when closed, throttling, or open.

B tt V l


19/87

B/ttery Valves

-ug ye *ouble &langed yeWafer ye

#vailable in ,olloin esins

B/ttery valves esine ,or tiht sh/t-of +'SO. ,all into tocateories: One is the valve that is provie ith an elastomer or plasticliner5

'he other tiht sh/t-of esin is the


20/87

B/ttery Valves +Cont.

4"#O O))."T

Concentric valve +3eroofset.5isc rotates aro/n the

centre a4is alloin ,ora potential >?0 rotation5Sealin is achieve bythe isc e,ormin theso,t seal res/ltin in ,/ll,riction thro/h the ,/lloperatin cycle5

DO5B&" O))."T

'he sha,t is ofset ,romthe centre line o, theisc seat an boyseal +ofset one. an

the centre line o, thebore +ofset to.5

T#0P&" O))."T

'he thir ofset is the eometry esin o, thesealin components not the sha,t position5

'he sealin components are each machineinto an ofset conical pro;le res/ltin in ariht anle cone5

'his ens/res ,riction ,ree strokin thro/ho/tits operatin cycle5 Contact is only mae atthe ;nal point o, clos/re ith the @0A anleactin as a mechanical stop res/ltin in noover - travel o, the isc seat5

Ball valve


21/87

Ball valve

A ball valve is a valve with a sherical disc'ball, the art of the valve

which controls the flow through it. he shere has a hole, or ort,

through the "iddle so that when the ort is in line with both ends of

the valve, flow will occur. When the valve is closed, the hole iserendicular to the ends of the valve, and flow is blocEed 7all

valves are straight%through flow valves which rovide ositive shut

off with "ini"al ressure dro and flow turbulence. he barrier to

flow is a ball which is rotated H5 degrees to the direction of flow.

he ball valve is very reliable. 2t can be engineered to

withstand ;26; ressure. It takes a quarter turn to

open or close them fully. 2t is widely used for #$%

#ff'shutdown alications and in secial cases for

regulating services.


22/87

Ball Valves Ball valves are /rable an /s/ally ork to achieve per,ect

sh/tof even a,ter years o, is/se5

se in stea*6 ,ater6 oil6 $as6 air6 corrosive !ids6 and canalso %andle slrries and dsty dry !ids5

#brasive an ;bro/s materials can amae the seats an the balls/r,ace5

'heir tiht sh/t-of characteristics correspon to #NSI Class IV anVI5

'he ;re-sa,e esin o, ball valves can be certi;e to #6I-?0Dhich speci;es the types o, seconary seats that are acceptableto control the leakin o, ammable /is hen the primary seat+/s/ally 6'*!. s/blimes /rin ;re5


23/87

/eatures3

;igh flow caacity.

+etal to "etal tri", soft seated tri".

ight shut off (-eaEage % A$2 class 2V) with soft seat.

+ini"u" obstruction for the flowing "edia.

I# ball and IV notch construction available. he V%notch

ball rovides nearly equal ercentage flow characteristic.T%e V-s%aped notc%c/t into the openin lip o,the ball provies a narroer area ,or /i o at

lo openin anles proviin more precise ocontrol than a plain-bore ball valve5 #lso knon assemente ball valve5

V-4otch Ball 5esign


24/87

'ypes O, Ball Valve)loat ball valve: *loatin ball in the ball valves means a ball

that is ,ree to EoatF beteen the seat rins5'he ball is hel on to seat rins5 In enerale can also say that the oatin ball valveshave oat ball an ;4e seat5

*loatin ball valves by its constr/ction /se an/pstream press/re to p/sh the ball aainst its

seat5 In eneral practice the oatin ball valve is

/se at lo press/re application /e to itsseat limitation +at hih press/re the ball isleanin to p/sh an broke the seat.5 *loatinball valves also /se at small si3e only /e toits iGc/lties to alin to seat i, the ball si3e isbi5

In eneral practice ,or pipin application ,orbelo >F si3e at 1H0 or >00 #NSI class sho/l

be /se oatin ball valves5

'ypes O, Ball Valve +Cont .


25/87

'ypes O, Ball Valve +Cont5.Trnnion 7onted: 'r/nnion mo/nte ball in the ball valves

means the ball is hel by a ;4e verticala4is5

In tr/nnion mo/nte the /pstreampress/re is absorbe by a bearin an thetihtness is achieve by a sprin insie theseat5 'his seat is p/she by a sprin to

have a tihten sealin5 'he tr/nnion mo/nte is capable to /se at

hih press/re application an lare si3eball valves itho/t maor problem5

#t hih press/re an lare si3e applicationthe tr/nnion mo/nte is s/perior to the

oatin ball valves type5 *or si3es >F an above +1H0 or >00 #NSI

class. or at #NSI class ?00 an above allsi3e it shall be /se o, tr/nnion mo/nte

ball valves5

oa n a v s r/nn on


26/87

oa n a v s r/nn on%o/nteIn eneral application the act/ate ball valves /se ,or sh/ton valve or blo on is

cateori3e as a critical application5 It serves a Sa,ety Instr/mente System +SIS. that hasa certain re8/irement o, Sa,ety Interity $evel +SI$.

/e to its critical role the ".D ball valvesare sally trnnion *ontedinstea o,oatin type5

Tor8e and t%e pstrea* pressreactin on the seat is the main point ,or choice thetype5 I, the press/re actin on the seat is hih the stem o, the oatin type can not bearthe press/re an m/ch o, it ill act on the Seal seat 'his ill mae the seat broken alsohen e close or open the valves the tor8/e ill be hih5 9e may nee to choose a biact/ator5

0n Trnnion type the ball is f9edan can redce so*e tor8e5 It also protects

t%e seathen the valve is close an hih /pstream press/re act on the ball5

B/t it also dependson the *anactrer capabilities5 Sometimes man/,act/rercapabilities to ,abricate a tr/nnion mo/nte ball valves is limite to 2F smallest si3e5 Inthis case the oatin type is /navoiable5

So as a concl/sion instr/ment ball valves /se as sh/ton or blo on applicationshall be tr/nnion mo/nte type an the /se o, oatin type is only acceptable i, the /seo, tr/nnion mo/nte type isnJt ,easible5

6 t l


27/87

he 64/ $AT-T+#0 2t worEs by changing the rocess fluidCs

flow rate by sliding a late ast a stationary hole.

Jnife 6ate valves are relatively ineBensive, have high caacity,

and are suited for slurry and dirty services. #n the other hand they have oor control characteristics, do not

rovide tight shut%off, and are not suited for corrosive services. 2t is a for" of Iguillotine%tye gate valve and is "uch used due

to its non%lugging body design. $on%abrasive slurry services such as in the ul F aer

industry. &or large dia"eter water services as found in waste water

syste"s.

6ate valve

#)T45-5)& VA0V)39otation of a "ovable disc with two

holes, which if rotated can rogressively cover two holes in the

stationary disc, can successfully throttle flow. he ositioned sliding disc designs are ideal for high%ressure

(u to >5,555 26), cavitating, abrasive, or erosive services,but are relatively eBensive and are not suited for sludge, slurry,

viscous, or fibrous services.

64/ $AT-T+#

#)T45-5)& VA0V)


28/87

.lab-type 'nie$ate

Gillotine-type 'nieGate Valve:

.lide $ate $illotine valves

are sed on lo, pressre !e$as or air!o, service as abloc' o valve2 T%ese valvesare available in bonneted orbonnetless desi$n5

t i 9 t l l


29/87

he eccentric lug rotary control valve features an eccentrically "ounted lug or ball, which co"bines

rotary valve efficiency with globe valve ruggedness.. Bcellent &low !haracteristic ;igh !aacity #ne%iece 7ody 9ugged !onstruction 9eliable erfor"ance he ;igh 9angeability #ne of the "ain advantages of the rotary lug valve is its free assage. *ue to the flow restrictor which

"oves crossways to the flow, the lug does not directly bears the brut of the flowing fluid. his confersa secial advantage on abrasive or adhesive "edia.

ccentric 9otary lug valve

)r. 4o. Type of VA0V Area of Application


30/87

> 15 B/ttery Valves

25 .a. !ontrol F 2solation (on%off) of Air, 6as, oBic !he"icals,Acids F AlEalies tc.

>.b. 8sed for control alication at higher valve sizes instead ofglobe valves

>.c. &or corrosive services, where body lining of globe valves

beco"es econo"ically unattractive.G. !ontrol F 2solation of ;igh e"erature, ;igh ressure

&luids tc.

G 7all Valves >. 2solation (on%off) of &luids at +oderate ressure F e".

G. DuicE #ening

< *iahrag" Valves >. #n'#ff alications in slurry service.

G. 6landless Valve ;ence +ost uitable for Vacuu" Alication

K Jnife dge 6ate Valves >. 2solation #f lurry F ul Alications

G. #n%#ff alication

4 >. 6lobe valve

G. 7elow ealed 6lobeValves

>. o control large range of rocess ara"eters, secially inetroche"ical, che"ical, fertilizer, oil and gas, ower, andother rocess lants

G. !ontrol F 2solation (on%off) of ;ighly oBic &luids F Lero-eaEage to At"oshere.

&ontrol Valves &haracteristic


31/87

Normally classi;e three typeso, characteristics

K/ick openin

$inear

!8/al percentae

S8/are root

%oi;e parabolic


32/87

#n inherent o characteristic in hich there is ma4im/m o ith minim/m travel5K/ick openin valves are typically /se ,or ON-O** service5se ,or processes here EinstantlyF lare o is neee5

&inear'he rate o, chane o, o is same to the rate o, chane o, valve travel5$inear characteristics are provie ,or most level control loops an loops here themeas/rement is linear an the variation in the press/re rop across the control valveis small5

>ualpercentage rovides equal ercentage increases in rate of flow for equal incre"ents of lug "ove"ent.

he equal ercentage valve offers an advantage over the linear valve at low flow rates. !onsider, at a >5M flow

rate of > "'h, the linear valve only lifts roughly KM, whereas the equal ercentage valve lifts roughly G5M.

Although the orifice ass area of both valves will be eBactly the sa"e, the shae of the equal ercentage valve

lug "eans that it oerates further away fro" its seat, reducing the risk of impact damagebetween the valvelug and seat due to quicE reductions in load at low flow rates.

?igher rangeability.

electing a valve with the correct flow characteristic (the relationshi between valve oening and flowcaacity) is very i"ortant.


33/87

Actually, a control valve has two characteristics, an 2$;9$ !;A9A!922! and an 2$A--*

!;A9A!922!.

he inherent characteristicof a valve is the characteristic ublished by the "anufacturer, based on tests

erfor"ed in a syste" where great care is taEen to ensure that the ressure dro across the test valve is

held constant at all valve oenings and flow rates. he inherent characteristic, therefore, reresents the

relationshi between valve flow caacity and valve oening when there are no syste" effects involved.

The inherent characteristic can be determined in a flow-test lab with a constant, pressure

drop, but what if the pressure drop is not constant as is >uite often the case@

he answer is because of theinstalled characteristic.

he 2nstalled characteristics of a control valve refer to the relationshi between the flowrate through the

valve and the valve travel, as the valve is oened fro" its closed osition to various degree of oening,

when the ressure dro across the valve varies.

$ote that, the ressure dro across the valve (*V) varies in "ost actual installation, influenced also by

various ressure%reducing devices in series with the control valve, such as the ie length, ie fittings and

various tyes of valves, flow"eter and rocess equi"ent.

$#0 2n actual flow conditions (installed characteristics) the equal M "oves toward linear and linear characteristics to

quicE oening characteristics. DuicE oening characteristics is undesirable for throttling alications since in dyna"ic

condition it "oves toward on%off characteristics.

A&TAT*)


34/87

Type: Pne*atic - Valve is operate by pne/matic s/pply on the act/ator5 6ne/matic

valve act/ators respon to an air sinal by movin the valve trim into acorresponin throttlin position56ne/matic act/ators /se air press/re p/shin aainst either a e4ible iaphram ora piston to move a valve mechanism5

% iaphram% 6iston operate

Sinle actin o/ble actin

"lectric- Valve is operate by electrical motor hich is co/ple to the valve sha,tthro/h ear bo45 !lectric motors have lon been /se to act/ate lare valves

especially valves operate as on)of +Esh/tofF. evices5 +ydralic-


35/87

-inear iston actuators rovide longer stroEes and can oerate at higher air ressures than can the

sring'diahrag" actuators. !o"ressed air is alied to a solid iston contained within a solid

cylinder. iston actuators can be single acting or double acting.

iston Actuators are used with on%off valves and also with large size valves which require longer

stroEe.

5iaphragm actuators*iahrag" actuators have co"ressed air alied to a fleBible

"e"brane called the diahrag". &igure shows a rolling

diahrag" where the effective diahrag" area is virtually constant

throughout the actuator stroEe.

he oularity of the sring'diahrag" actuator is due to its lowcost, its relatively high thrust at low air suly ressures, and itsavailability with Ifail%safe srings.

ring diahrag" actuators are the "ost widely recognized andused by control valve suliers.

i"listic design ,few "oving arts, and easy to "aintain.

5iaphragm actuator

)cotch +oke ( *ack #inion3 heyare the"ost co""only used "echanis"s in on%off rotary valve

actuators because of their high torque roduction

&obe #crobat D50

oc/ment

In aition to the /i type act/ators also vary in the


36/87

In aition to the /i type act/ators also vary in themanner in hich the enery is store to operate the valveon eman as ,ollos:

.in$le-actin$ cylinder< .prin$ #etrn - !nery is

store by means o, a compresse sprin Doble-actin$ cylinder- !nery is store /sin a vol/me

o, compresse /i

'he type o, act/ation re8/ire also epens /pon theapplication site ,acilities an also the physical spaceavailable5

#ltho/h the *a=ority o actators/se ,or s%tdo,nvalvesare o, the sprin$ retrn type/e to the ail saenatre o sprin$ retrn syste*s2

#ac' ( Pinion Actator

he valve alication engineer "ust choose between the two readily available fail%safe sche"es for control valves,

either fail open or fail closed his "eans Nwhat osition will the valve "ove to should the suly air or control


37/87

either fail open or fail closed. his "eans what osition will the valve "ove to should the suly air or control

signal to the valve falls awayN. his is i"ortant to safe guard the rocess at various laces so so"e valves will be

fail oen and so"e fail close.

/ail open% A condition wherein the valve closure "e"ber "oves to an oenosition when the actuating energy source fails.

/ail close% A condition wherein the valve closure "e"ber "oves to a closedosition when the actuating energy source fails.

/ail safe% A characteristic of a articular valve and its actuator that uon loss ofactuating energy suly will cause a valve closure "e"ber to be fully closed, fullyoen, or re"ain in the last osition, whichever osition is defined as necessary torotect the rocess.

/ail lock% neu"atic locE%u syste"s are used with control valves to locE in

eBisting actuator loading ressure in the event of suly ressure failure.

his is done by installing a NlocEu valveN inline with the neu"atic actuators air

line traing air inside the actuator under NfailN conditions. When the locEu valve

shuts, no air can enter or eBit the control valves actuator, which "aEes the control

valve hold its osition.

#ositioner


38/87

2n valves without a ositioner, when the valve is given a co""and to oen to a certain oint, there is no

feedbacE to verify that the valve has oened to that osition.

With a valve ositioner, the co""and is given and the valve ositioner reads the oening, verifying the osition

and read/usting until it gets it to the eBact osition needed. his allows for great recision in the valve ad/ust"ent

7y definition, apositioneris a device attached to an actuator that receives an electronic or neu"atic signal fro"

a controller and co"ares that signal to the actuatorCs osition.2f the signal and the actuator osition differ, the ositioner sends the necessary owerOusually through

co"ressed airOto "ove the actuator until the correct osition is reached.

A ositioner ensures that for a given

inut signal, the valve will always

atte"t to "aintain the sa"e osition

regardless of changes in valvedifferential ressure, ste" friction,

diahrag" hysteresis and so on.

A ositioner "ay be used as a signal

a"lifier or booster.

2t accets a low ressure air control

signal and, by using its own higher

ressure inut, "ultilies this to rovidea higher ressure outut air signal to

the actuator diahrag", if required, to

ensure that the valve reaches the

desired osition.

here are four basic valve ositioner tyes0 neu"atic, electronic, electro%neu"atic and digital. neu"aticvalve ostioners co""unicate with air.


39/87

lectricvalve ositioners use electric signals1 single or three%hase A! or *! current is used. lectro%neu"aticvalve ositioners taEe an electric signal and convert it to a neu"atic (air) signal. *igitalvalve actuators use a "icrorocessor to "onitor the valve accurately.

A fre>uently asked >uestion is, %Chen should a positioner be fitted@

A ositioner should be considered in the following circu"stances0

>. When accurate valve ositioning is required.

G. o seed u the valve resonse. he ositioner uses higher ressure and greater air flow to ad/ust

the valve osition.


40/87

logic when the valve is fully open or fully closed.

)witches are installed on electric motor-driven valves to open the circuit and

stop driving the motor when the valve is at its limit !fully open or closed". Thename Dlimit switchE is also used to describe switches installed to signal

when a valve is at or beyond a predetermined position.

/or ha'ardous area, switch shall be either intrinsically safe or switchmounted in ex-proofing housing.

Chen specifying the limit switches, one should specify the re>uired contactratings, the contact configurations !)#5T, 5#5T, and so on", and the type of

housing re>uired. Typical choices include weatherproof, explosion proof etc.

T+#) / 01T )CT&?) )53

."N.O# TA#G"T ."N.O#D0.TANC"

.>0TC+

#AT"

"NV0#ON7"NTA&

."N.0T0V0T0".

ADVANTAG". D0.ADVANTAG".

&i*it.,itc%

#ny 6hysicalContactre8/ire

>


41/87

Solenoi valves are o,ten ,o/n in applications inhich a control valve /ner certain conitions m/stbe 8/ickly riven to the ,ail position

'he solenoi valve as a control valve accessory is

/se +1. 'o operate on)of pne/matic act/ators

+2. 'o interr/pt the action o, mo/latin valves bysitchin air or hyra/lic press/res5

In orer ,or the system to sh/t on +valve to close.in case o, loss o, poer or emerence o, an /nsa,econition it is esirable ,or the solenoi valve to be

contin/o/sly eneri3e /rin normal operation5'his ill /arantee that any ,ail/re loss o, poer ora broken ire ill ca/se a ,ail-sa,e action5

9e can /se brass6 al*in* or even ?1@ ..,orthe boy material since all o, this material iscompatible ith the instr/ment air5

'ho/h solenoid valve *aterial is ?1@&.. as*ini**or per proect speci;cations as it iscorrosion resistant2

3


42/87

9hen the solenoi valve is eneri3e there is some heat enery enerate bythis con/ctors inin5 Since the con/ctors inin issipate some heatenery the ins/lation m/st en/re this heat5

I, the ins/lation isnJt stron eno/h to en/re aainst the heat then it ill melt

or b/rnt5 */rthermore the broken ins/lation ill ca/se a short circ/it an thesolenoi ill ,ail to operate5

In eneral t%e inslation o solenoid valve coil can be *ade ro* paper6polyester6 polyret%ane6 nylon etc5

.olenoid Valve Coil 0nslation Class 7a9i** Te*peratre

B 1? de$ C

) 1 de$ C

+ 1 de$ C

In eneral application ,or sh/ton valve trierin the vendorill providethe te*peratre rise data o t%e solenoid at ll load Eener$i/edF5 9iththis temperat/re rise ata t%ey ,ill provide standard inslation classand state t%e *a9i** a*bient te*peratre or t%at solenoid valves 5

*or e4ample the solenoi valves have an inherent temperat/re rise @00C at

,/ll loa5 By proviin ins/lation class * +ma4 temperat/re 1HH0C. it ill bealloe to operate at ?H0C ambient temperat/re5 In most application theambient temperat/re ill not e4cee M00C there,ore it ill have 2H0C e4trathermal capabilities5 'his e4tra thermal capability can be /se to e4ten the

solenoi valve li,e e4pectancy5

uly ressure regulators, co""only called airsets,

Air filter regulator


43/87

y g y

reduce lant air suly to valve ositioners and other

control equi"ent.

hey erfor" two critical functions0 roviding a constant air

suly ressure to the instru"ent or valve, and filtering the

instru"ent air, that is to re"ove "oisture, oil, and all

articles that are 4 P or larger.he pressure-reducing functionis essential to a lantCs

erfor"ance and safety. +ost lant instru"ent air syste"s

oerate at ressures of >55 si (@.H bar) or higher, while"ost control valves and other instru"ents are designed to

run at "uch lower air suly ressuresOas low as G5 si

(>.K bar) in so"e cases.

Bceeding the rated suly ressure can lead to early

failure, "echanical da"age, syste" shutdowns andotentially unsafe conditions.

2t is often urchased with the valve, "ounted, and ied.

An air set "ust be used when the ressure rating of the

actuator or ositioner is lower than the air suly ressure.

$eneral filter material0 intered olyroylene, intered

olyethylene

Air &ilter

9egulator


44/87

+and-,%eel


45/87

his is the basically the fluid which asses through the valve when the valve is fully closed. o this

leaEage shall deend on the contact of the valve lug seat with the seating force alied for holding

the lug over the seat.

0eakage&lass

1aximumAllowable

Test1edium

Test #ressures

22 5.4M of rated valve caacity air or waterK4%@5 26 or "aBi"u"

difference ressure,whichever is less

222

5.>M of rated valve caacity

air or water

K4%@5 26 or "aBi"u"


2V 5.5>M of rated valve caacity air or waterK4%@5 26 or "aBi"u"


V

5.5554 "l er "in. er inchorifice dia"eter (seatdia"eter) er si

differential

water>55 2 "ini"u" or "aBi"u"

difference ressure

V2 9efer to table ad/acent

air ornitrogen

45 2 or "aBi"u" differenceressure, whichever is

lower

eat -eaEageAccording to A$2 7>@.>5K%>H3@ (&!2 35%G)

4ominal #ort5iameter

ml #er 1inuteBubbles #er

1inute

>.55 5.>4 >.55

>%>'G 5.


46/87

Class 02Ientical to Class II III an IV in constr/ction anesin intent b/t no actal s%op test is *ade2

Class 002Intene ,or o/ble-port or balance sine-portvalves ith a metal piston rin seal an metal-to-metalseats5 #ir or ater at MH to ?0 psi is the test /i5

Allo,able lea'a$e is 2 o t%e rated ll opencapacity2

Class 0002Intene ,or the same types o, valves as in ClassII5 #lloable leakae is limite to 21 o rated valvecapacity2

Class 0V2Intene ,or sinle-port an balance sinle-portvalves ith e4tra-tiht piston seals an metal-to-metalseats5 &ea'a$e rate is li*ited to 21 o rated valvecapacity2

Class V2Intene ,or the same types o, valves as Class IV5'he test /i is ater at 100 psi or operatin press/re5$eakae alloe is limite to H " 10 ml per min/te per incho, ori;ce iameter per psi iferential5

Class V020ntended or resilient-seatin$ valves2'he test/i is air or nitroen5 6ress/re is the lesser o, H0 psi oroperatin press/re5 'he leakae limit epens on valvesi3e an ranes ,rom 051H to ?5DH ml per min/te ,or valvesi3es 1 thro/h inches5

!-A 2V is also Enown as "etal to "etal. 2t is the Eind of leaEage rate you can eBect fro" a valve with a "etal

lug and "etal seat.

!-A Vl is Enown as a soft seat classification. oft eat Valves are those where either the lug or seat or both

are "ade fro" so"e Eind of co"osition "aterial such as eflon or si"ilar.

/lashing &avitation #henomena


47/87

/low

direction

#ipe

/low restriction

nlet pressure

utlet pressure

Vapor pressure

Vena &ontracta pressure

p1

p2

pv

pvc

/lashing2f the ressure at the vena contracta dros below the vaour ressure of

the liquid, bubbles will for" in the flowing strea". 2f the ressure


48/87

q , g

downstrea" re"ains below the vaour ressure, the bubbles will

re"ain and the rocess is said to have Iflashed. &lashing can

roduce erosion da"age, nor"ally at the oint of highest velocity at

or near the seat line of the valve lug and the seat ring.

When the liquid flashes into vaour, there is a increase involu"e, resulting in the increase in the velocity of the fluid.

;ence this high velocity will erode the surface.

&lashing da"age can be identified as s"ooth olished

aearance of erode surface. 2t is usually at or near seat line of

the valve lug and seat. &lashing da"age is "arEed by shiny,

s"ooth gouges in "aterial.

When a liquid flashes into vaor, there is a large increase involu"e. 2n this circu"stance, the iing downstrea" of a valve

needs to be "uch larger than the inlet iing in order to Eee

the velocity of the two%hase strea" low enough to revent

erosion. he ideal valve to use for such alications is an angle

valve with an oversized outlet connection.

o rotect

the valve the valve "aterial "ust be hardened. 2f there is >55Mflashing then the valve should be slightly oversized in order to

acco""odate the increased volu"e and Eee velocity of

vaour low enough.

&avitation

!avitation is said to have occurred if the downstrea" ressure


49/87

!avitation is said to have occurred if the downstrea" ressure

recovery is sufficient to go above the vaour ressure,

collasing the bubbles, releasing energy, "aEing noise, and

causing erosion.

!hoEed cavitation is the oint where the vaorization of the

fluid reaches sonic velocity in the valve ort and li"its the

flow through the valve.

!avitation da"age can be identified as rough and

itted surface. !avitation da"age "ay eBtend to the

downstrea" ieline if that is where the ressure

recovery occurs.

*estruction is due to the i"losions( the bubblescollase ) that generate the eBtre"ely high%ressure

shocE waves in the substantially non%co"ressible

strea". !avitation is usually couled with vibration

and a sound liEe rocE frag"ents or gravel flowing

through the valve.!avitation *a"age

2n order to -2+2$A !AV2A2#$0 2nstall two or "ore control valves in seriesas ressure dro is distributed.

he "ore treacherous the flow ath through a articular valve the less


50/87

he "ore treacherousthe flow ath through a articular valve, the less

liEelihood eBists for cavitation.

2nversely, the valves "ost liEely to cavitate are the high recovery valves

(ball, butterfly, gate) as the flow ath is less co"licated.

!ontrol valve designs that are less liEely to cavitate are ones having"ultiath and "ultiturn flow aths.

-abyrinth%tye valves avoid cavitation by a very large series of right%angle

turns with negligible ressure recovery at each turn..

he "ultiste ' "ultistage valvescan avoid cavitation by relacing a single

and dee vena contracta with several s"all vena contracta oints as theressure dro is distributed.

+ulti%6rooved!ascade tri" for non%co"ressible fluid alications. here

are QRH grooves designs available deending on ressure dro and

otential for cavitation. he fluid asses through the flow ath generated

by incororating angled flats onto the surface of the lug. he ressure

dro rogressively reduces as it asses through the grooves of the tri".

7y roer "aterial selection. uch as -iEe @ ' !#-+#$#: @ coating'

--2 coating ' A--#: @ which are liEely to survive longer.

he "ultiste valves

+8-2 A; 92+ !2#$

4oise Theory


51/87

A rando" "iBture of sound and ressure waves of various a"litude and frequency, whicheole do not liEe.8nit of noise S d7A (*ecibels) T G5-og (Bisting sound ressure level ' .555G "icro bar).

yical noise li"it is Q4 d7A before so"e Eind of action is required.

)ource of valve noise

+echanical noiseS 2t roduces high "echanical stress% fatigue failure of vibration

art. +echanical noise can be reduced by i"roved design to suress vibrationby good suort and rugged construction. Vibration of valve co"onents S it is due to lateral "ove"ent of valve lug against

the guide surface. he sound level roduce will nor"ally have frequency lessthan>455 ;z and is Enown as "etallic rattling.

;ydrodyna"ic noiseS 2t is due to cavitation and flashing. 2t is because ofcollasing of vaour bubbles.

Aerodyna"ic $oiseS Aerodyna"ic noise is generated by the turbulence created inthe flow of vaor, gas, or stea" as the fluid asses through a control valve

4oise control #ath treatment


52/87

#ath treatment

nsulation of pipe0

Thermal nsulation0< to 4 d7A of noise attenuation er inch.

Acoustical nsulation3 Q to >5 d7A er inch

?eavy duty pipe )ilencer3

n-line silencers3Absorb sound energy

Alied when source treat"ent is insufficient !ost effectively rovide u to G4d7A attenuation

tandardcheduleK5 ie

>>5 d7A

cheduleQ5 ie

>5@ d7A

Acoustic2nsulation(G%inches)

H@ d7A

tandardcheduleK5 ie

>>5 d7A

ilencer

Q4 d7A

tandardcheduleK5 ie

Q4 d7A

4oise control )ource treatment

revents noise at its source


53/87

revents noise at its source,

+ini"izes turbulence.

taging ressure dro through use of diffusers

*ividing u flow ath through slots or drilled holes

xample3

-ow $oise ri" S !age style (e.g. Whiser tri")

Whiser &lo ($oise reduction u to >5 d7A)

Whiser 2 ($oise reduction u to >Q d7A)

Whiser 222 ($oise reduction u to


54/87

S#*!P 'here are also to methos to achieve a ;re-sa,e esin by sin$ a

fre-proo co*ponentor by sin$ a non fre-proo co*ponentbt spported by a special desi$n t%at ,ill prevent lea'a$eater t%e co*ponent is *elt2

T%e frst *et%odto achieve a ;re-sa,e esin by /sin a ;re-proo,component /s/ally is re,errin as an inherently ;re-sa,e valve5 s/ally

this type o, valve is a *etal seated valve by sin$ a $rap%iteseat insert Ein ball valve or btter!y valveF and $rap%ite ste*pac'in$5 By /sin raphite as a seat insert an stem packin theraphite ill remain stan even a,ter ;re e4pos/re5

T%e second *et%odto achieve a ;re-sa,e esin by /sin a non;re-proo, component /s/ally is re,errin as ;re-teste valve5 T%isvalve is sin$ a t%er*oplastic seat *aterial and at%er*oplastic ste* pac'in$ *aterial sc% as PT)"5 In the seatesin even tho/h the seat is thermoplastic it is esine so thathen the thermoplastic is meltin /e to hih temperat/re e4pos/re

!S 'riers


55/87

!S 'riers

Pressre sensin$ +i$% ( &o,

'hese kin o, triersproviehih an lo press/re sensin onas or li8/is an can be ;tte itheither an a/tomatic or man/al

reset5

)sible &in' */sible links are set to melt an

activate an !S system in the evento, ;re5

6!(*O(%#NC! %!#S(!%!N' *O( !S


56/87

V#$V!

*or !S valves it is essential to kno that the valve is capable o,proviin the re8/ire level o, sa,ety per,ormance an that thevalve ill operate on eman5

'he re8/ire level o, per,ormance is ictate by the Sa,etyinterity level +SI$.5

'he metric ,or meas/rin the per,ormance o, a sa,ety ,/nction iscalle the Avera$e Probability o ailre on de*and+or6*av. an this correlates to the SI$ level as ,ollos:

.0& P)Dav$

M Q 10RHto 10RM

> Q 10

RM

to 10

R>

2 Q 10R>to 10R2

1 Q 10R2to 10R1

'ypes O, 6er,ormance 'ests


57/87

'ypes O, 6er,ormance 'ests

'here are 2 types o, testin methos available: Proo test- # man/al test that allos the

operator to etermine hether the valve is inthe Tas oo as neT conition by testin ,or

all possible ,ail/re moes an re8ires aplant s%tdo,n2 +L!N!(#$$U ON! ONC! IN# U!#( O( '9O U!#(S.

Dia$nostic Test- #n a/tomate on-line test

that ill etect a percentae o, the possible,ail/re moes o, the sh/ton valve5 #ne4ample o, this ,or a sh/ton valve o/l be

6#('I#$ S'(O! '!S'INL


58/87

+6S'.

Partial stro'e testin$+6S'. is a techni8/e /se inSIS to allo the /ser to test a percentae o, thepossible ,ail/re moes o, a sh/t on valve itho/tthe nee to physically close it5

'he 6S' is /se to check the ,/nction o, the sa,eposition o, !S valves5

# s/ccess,/lly e4ec/te partial stroke emonstratesthat certain /nresolve errors that o/l otherise o/netecte s/ch as sprin ,ract/res in the sprin

chamber o, the pne/matic act/ator5'he test can be starte both locally on the evice in a

time-controlle manner or ,rom remote5


59/87


60/87

7ec%anical Ha**ers

# evice is inserte into the valve anact/ator assembly that physically preventsthe valve ,rom movin past a certain point5

'hese are sed in cases ,%ereaccidentally s%ttin$ t%e valve ,old%ave severe conse8ences or any

application here the en /ser pre,ers amechanical evice5

%echanical limitin methos areine9pensivein terms o, capital aninstallation costs5

'hese methos are *anally initiatedinthe ;el an are *anpo,er intensive5

# limit sitch or vis/al inspection is /se tocon;rm valve movement5

One o, the biest rabacks to these


61/87

Drin$ nor*al operation t%e device ispassive and ,ill allo, t%e valve to ".D

on de*and2

>%en a partial stro'e test is re8ired6 t%edevice is Ien$a$edJ and t%e ".D valve ,illonly travel to t%e specifed percenta$e o

stro'e2 T%edevice *ec%anically prevents *ove*ent

past t%e interloc'

7ec%anical Partial .tro'e Test Devices%o,n in disen$a$ed position

7ec%anical Partial .tro'e TestDevice s%o,n in en$a$ed position2

6S' %ethooloies +Cont5.


62/87

Position Control 6osition control ses a positioner to *ove t%e valve to a pre-

deter*ined point5 'his metho can be /se on risin stem anrotary valves5

Since most emerency block valves are not installe ith apositioner this metho does re8ire installation o additional%ard,are2

6ositioner operation also re8ires an analo$ otpt hich is

typically not installe in SIS applications5 Conse8/ently cost is a*a=or dra,bac',or the position control metho5 # li*it s,itc% or position trans*ittercan be /se to etermine

an oc/ment the s/ccess,/l completion o, the tests5 I, a smart positioner is /se ,or the position control a +A#T

*aintenance station can collect t%e test inor*ation and$enerate test doc*entation2O, co/rse the /se o, a smart

positioner an maintenance station ,/rther increases the capital cost5 'he positioner does contribte to t%e sprios trip rate/rinnormal operation since the positioner can ,ail an vent the air ,romthe valve5

Bt ,%en a solenoid is installed bet,een t%e positioner andt%e actator t%e saet nctionalit is never lost drin t%e

6S' %ethooloies +Cont5.


63/87

.olenoid # partial-stroke test can be accomplishe by plsin$ a solenoid

valve5 'he solenoi can be the same solenoi /se ,or valveact/ation res/ltin in a lo, capital and installation costs,orthe metho5

I, the act/ation solenoi valve is /se this metho ,ill also testt%e solenoid valve nctionality5

Valve travel confr*ation is acco*plis%ed by a li*it s,itc%or position transmitter alloin a/tomatic oc/mentation o, test

stat/s5 'he test can be pro$ra**ed in t%e .0. lo$ic solverith thetest bein implemente a/tomatically base on a prorammecycle time or initiate by the operator on a maintenance sche/le5

Since the valve is never bypasse or isable the valve remainsavailable ,or sh/ton /rin the test5 #s ith the other partial-stroke testin methos a *aintenance bypass is re8iredto

allo maintenance to be per,orme on-line itho/t a processsh/ton5

#,ter all the solenoi is bein e-eneri3e ,or the test an re-eneri3e to stop the test5

I, the solenoi valve oes not reset the test becomes a trip5

Bene;ts O, 6S'


64/87

Bene;ts O, 6S'

(e/cin the probability o, ,ail/re on eman5

!4tension o, the time beteen comp/lsory plantsh/tons5

6reictin potential valve ,ail/res ,acilitatin the pre-orerin o, spare parts5

6rioritisation o, maintenance tasks5 I, the sa,ety is o, an appropriate level the nee ,or

costly re/nant valves may be eliminate5

A)1 B=;.= and B=;.F.

)tandards *elevant to &ontrol Valves


65/87

A+ 7>@.> 0 !ast 2ron ie &langes and &langed &ittings. his tandard for !lasses G4, >G4, G45 !ast 2ron

ie &langes and &langed &ittings covers.

A+ 7>@.4 0 ie &langes and &langed &ittings. he standard includes flanges with rating class >45, 455, and G455 in sizes $ >'G through $ GK.

A)1 B=;.=8-=GG

*efines &ace%to%&ace *i"ensions of valve bodies

)A )HF.=G &or ;ydro testing of !ontrol Valves (-atest dition)

A)1 B=;.I:-=GG; 3Valves - /langed, Threaded and Celded nd

*efines design criteria for valves with &langed, hreaded and Welding ends

*efines "ini"u" wall thicEness require"ents

*efines ressure%e"erature 9atings for various "aterials

er"its Asse"bled ;ydrostatic ressure ests

A4) B=;.=8:-=GH; !/& H8-9"3 )tandard for &ontrol Valve 0eakage &lassification !/luid &ontrol nstitute"

tandard for eat -eaEage !lassification stablishes test rocedures and seat leaEage classes

iB -eaEage !lass *esignations % !lass 2 through V2

A4)()A-HF.8F.8=-9888 !*988F" !ontrol Valve er"inology

A)1(A4) B=;.:H J =GG;

- *i t t l &l $ G@ th h $ @5


66/87

-arge *ia"eter teel &langes0 $ G@ through $ @5

American #etroleum nstitute !A#"3 A2 * @& &ire est for Valves

A2 * 4HQ Valve 2nsection F esting A2 * 4HH +etal lug Valves S &langed, hreaded and Welded nds A2 * @5G teel, 6ate, 6lobe F !hecE Valves for izes *$ >55 and "aller for the

etroleu" and $atural 6as 2ndustries A2 * @5Q +etal 7all Valves S &langed, hreaded, and Welded nds A2 * @5H 7utterfly Valves0 *ouble &langed -ug and Wafer ye. A2 * G555 Venting At"osheric and -ow ressure torage anEs $on%refrigerated and 9efrigerated

4ational Association of &orrosion ngineers !4A&"3 $A! +95>5< and $A! +95>34 and 0 etroleu" and $atural 6as 2ndustries +aterials for use in ;G%!ontaining

nviron"ents in #il and 6as roduction art >0 6eneral rinciles for election of !racEing%9esistant 2rons S art


67/87

y ) ) p electronic sa,ety-relate systems

0"C@111:*/nctional sa,ety o, SIS ,or the process in/stry sector5 It

imposes aitional re/nancy re8/irements to achieve hih SI$ ratinthese can be mitiate here ianostics are shon to be /se toprovie preictive maintenance5

T5V Certifcate:'he p/rpose o, this paper is to s/mmari3e the testan certi;cation policies /se /rin a 'V certi;cation o, a sa,etycomponent)s/bsystem5 'hese components)s/bsystems are typicallyelectrical)electronic) prorammable electronic systems5

AP0 KEValve 0nspection and Testin$F:'he stanar coversinspection s/pplementary e4amination an press/re test re8/irements,or both resilient-seate an metal-to-metal seate ate lobe pl/ball check an b/ttery valves5 6ertains to inspection by the p/rchaseran to any s/pplementary e4aminations the p/rchaser may re8/ire atthe valve man/,act/rer7s plant5

AN.0


68/87

the relevant standard A+ 7>@.>5.


69/87

NAC" Certifcation,or Corrosive)So/r Services an services

ith M-MStanar ,orcontrol valve leakae5 'he seat leakae test proce/res shallbe e4ec/te ,or all control valves o, Class V or VI5

C#;OG"N0C T".T: # lo temperat/re or a cryoenic test shallbe mae on selecte control valves /se in lo temperat/re

service +on to -H0AC. or in cryoenic service +belo -H0AC.5 07PACT T".T0NG: Is one ,or carbon steel components /se

in lo temperat/re services+belo 1H erees. NON D".T#5CT0V" T".T.ENDTF: (aioraphy 'estin ye

'est

ONT#O& VA&V" .040NG CA&C5&AT0ON.!ontrol valve izing is eBtre"ely critical and involves a lot of calculations. 7eing and ! we donCt directly

calculate a valve !V but we "ust be aware of each ad every governing factor and be caable of choosing the "ost


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calculate a valve !V, but we "ust be aware of each ad every governing factor and be caable of choosing the "ost

correct valve according to our require"ents.

*lo CoeGcient +CV.

he valve flow coefficient, !V is the nu"ber of 8.. gallons er "inute of water at @5 degrees & which will ass through a

given flow restriction with a ressure dro of > si.

&or eBa"le, a control valve which has a flow coefficient, or !V, of >G has an effective ort area that it asses >G gallons

er "inute of water with > si ressure dro.

Jv is the flow coefficient in "etric units. 2t is defined as the flow rate in cubic "eters er hour "


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! &low coefficient (Jv,!v) Various (2! @54

&9 9eynolds nu"ber factor >

&Y ecific heat ratio factor >

+ +olecular "ass of flowing fluid Jg'E"ol

$ $u"erical constants Various see note >

> 2nlet absolute static resure"easured at oint A

Ea or bar

ee note G

G outlet absolute static resure"easured at oint 7

Ea or bar

ee note G

c Absolute ther"odyna"ic criticalressure

Ea or bar

r 9educed ressure (>'c) >

v Absolute vaour ressure of theliquid at inlet te"erature

Ea or bar

d *ifferential ressure betweenustrea" and downstrea" ressuretas (>%G)

Ea or bar

D Volu"etric flow rate +

W +ass flow rate Jg'h

B 9atio of ressure differential to inletabsolute ressure(d'>

>

B ressure differential ratio factor of acontrol valve w'o attached fittings atchoEed flow

>

ee note K

B ressure differential ratio factor of acontrol valve w'o attached

fittings at choEed flow

>

ee note K

y"bol *escrition 8nit

: Bnsion factor >

L !o"ressibility factor >

$#

>. o deter"ine the units for the nu"erical constants,

di"ensional analysis "ay be erfor"ed on the

aroriate equations using the units given in table


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v Jine"atics viscosity +G'sec

ee note *ensity of fluid at >and > Jg'"' Z5 9elative density (Z>' Z5) T> for waterat >4X!

>

Y ecific heat ratio >

[ Velocity head loss coefficient of areducer, eBander or other fittingattached to a a control valve

>

[> 8strea" velocity head losscoefficient of fitting

>

[G downstrea" velocity head losscoefficient of fitting

>

[7> 2nlet 7ernoulli coefficient >

[7G outlet 7ernoulli coefficient >

G. > bar T >5G Ea T >54a

centistoEes T >5%4 "G'sec

K. hese values are travel related and should be stated bythe "anufacturer

4. Volu"etric flow rates in cubic "etres er hour, identified

by the sy"bol D, refer to standard conditions. he

standard cubic "etre is taEen at >5>


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Si3in e8/ations ,or Non-Compressible*l/is


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o $ote

* choEed flow or \ch T &-G (>%&&B v)

;ere \ ] \ch

Where. !T !v in 86'"in.

D flow rate in + inlet absolute ressure in Ea or bar

G outlet absolute ressure in Ea or bar

ecific weight at inlet conditions Zg


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D flow rate in + inlet absolute ressure in Ea or bar


&- co"bined ressure recovery factor and iing geo"etry factor

& S iing geo"etry factor

secific weight at inlet conditions

(Ga)

o e ow

he basic liquid sizing equation tells us that the liquid flow rate through a controlvalve is roortional to the square root of ressure dro. his si"le relationshi is

shown grahically by the green ortion of the grah in &igure >. ($ote that the scale

of the horizontal aBis is the square root of ressure dro.) his linear relationshi

d t l h ld t A th d i i d th fl h i t


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does not always hold true. As the ressure dro is increased, the flow reaches a oint

where it no longer increases. #nce this haens, additional increases in ressure

dro across the valve do not result in additional flow, and flow is said to be choEed.;ere we will call this li"iting or choEing ressure dro the er"inal ressure *ro,

\. (he sa"e thing is also so"eti"es referred to as the Allowable ressure *ro,

\allowable

, so"eti"es as the +aBi"u" ressure dro, \+aB

, and so"eti"es as the

!ritical ressure *ro, \!rit

.)


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o $ote

* choEed flow or \ch T &-G (>%&&B v)

;ere \ ^ T \ch

When above is true, the flow is choEed.;ence, for $on%!o"ressible fluids(liquids etc)

\"in is taEen in the deno"inator ie.

"aller value between \ and \ ch


D flow rate in + inlet absolute ressure in Ea or barG outlet absolute ressure in Ea or bar

& S iing geo"etry factor

&- -iquid ressure recovery &actor

&& -iquid critical ressure ratio factor


82/87

Where.

! i !v in 86'"in.

D flow rate in "

_>'Z5 T> for water at >4X!

$> %$u"erical constant

d >%G

&& -iquid critical ressure ratio factor

v absolute vaour ressure at inlet Ea ' bar

> inlet absolute ressure in Ea or bar


& iing geo"etry factor

&- -iquid ressure recovery &actor

&- co"bined ressure recovery factor and iing geo"etry factor


83/87


D flow rate in "

_>'Z5 T> for water at >4X!

$> %$u"erical constant

d (>%G )

> inlet absolute ressure in Ea or barG outlet absolute ressure in Ea or bar

&9 9eynoldCs nu"ber factor

*l/is


84/87

Where.

!T !v in 86'"in.

D flow rate in " inlet absolute ressure in Ea or bar

Goutlet absolute ressure in Ea or bar

>2nlet absolute te"erature in Jelvin

L co"ressibility factor

B (>%G)'>


85/87

Where.

!T !v in 86'"in.





B (>%G)'>

S


86/87

Where.

!T !v in 86'"in.D flow rate in " inlet absolute ressure in Ea or bar


> 2nlet absolute te"erature in Jelvin


B (>%G)'>

B ressure differential ressure factor S vendor data

o $ote

=^T&y=t

When above is true, the flow is choEed.

At choEed flow, the gas attains sonic velocity, >+ach


87/87

Where.

! !v in 86'"in.





&iing geo"etry factor

B ressure differential ressure factor S vendor data

&` secific heat ratio factor

Z>% density in Eg'"< at ressure > and te". >

valves ppt.pptx

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