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PRESENTATION ON MECHANICALPRESENTATION ON MECHANICALVALVESVALVES
BYBY ALOK KUMAR SINGHALOK KUMAR SINGH
PURPOSE OF USING VALVES
ValvesValves areare usedused toto controlcontrol thethe flowflow of of liquids,liquids,solidssolids andand gasesgases inin industrialindustrial asas wellwell asas domesticdomesticsituationssituations andand areare oneone of of thethe majormajor pipingpipingcomponentscomponents..
TheThe mostmost commoncommon andand familiarfamiliar valvesvalves areare thethetapstaps usedused inin thethe homehome toto controlcontrol thethe flowflow of of hothotandand coldcold waterwater.. InIn thethe oiloil industry,industry, valvesvalves areare aamajormajor elementelement inin thethe controlcontrol of of operationsoperations..AboutAbout 88--1010%% of of thethe totaltotal capitalcapital expenditureexpenditure of of thethe chemicalchemical industryindustry isis usedused forfor procurementprocurement of of valvesvalves..
VALVES ARE USED FOR ONE OR MORE OF
THREE MAIN PURPOSES
To control the rate of flowTo control the rate of flow
(throttle);(throttle);
To shut off/permit flow (ON/OFFTo shut off/permit flow (ON/OFF
function);function);To isolate systems and protectTo isolate systems and protect
productsproducts..
VALVE CLASSIFICATION BASED ONVALVE CLASSIFICATION BASED ON
FUNCTIONFUNCTION
VALVES
ON/OFF REGULATION
GATE
BALL
GLOBE
NEEDLE
NON-RETURN
CHECK
SPECIAL
MULTI-PORT
FLUSHBOTTOM
PLUG
PISTON
DIAPHRAGM
BUTTERFLY
PINCH VALVE
BUTTERFLY
DIAPHRAGM
PISTON
PINCH
FLOAT
FOOT
LINE BLIND
VALVE CLASSIFICATION BASED ONVALVE CLASSIFICATION BASED ON
END CONNECTIONSEND CONNECTIONS
VALVES
SCREWD
ENDS
SOCKET
WELD ENDS
FLANGED
ENDS
BUTT
WELD ENDS
SOCKETTED
ENDS
WAFER
TYPE ENDS
VALVE CLASSIFICATION BASED ONVALVE CLASSIFICATION BASED ON
MATERIAL OF CONSTRUCTIONMATERIAL OF CONSTRUCTION
VALVES
CASTIRON
BRONZESPECI ALALLOY
GUNMETAL
CARBONSTEEL
SSALLOY
CARBONSTEEL
POLYPROPY--LENE
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STANDARDS OF MANUFACTURESTANDARDS OF MANUFACTURE
Metric/Imperial dimensions;Metric/Imperial dimensions;
British StandardsBritish Standards -- BSBS
German StandardsGerman Standards -- DIN;DIN;
US StandardsUS Standards -- ANSI (previously ASA);ANSI (previously ASA);
American Petroleum InstitutionAmerican Petroleum Institution -- API. (flangesAPI. (flangesand other equipment are commonly used in the oiland other equipment are commonly used in the oilindustryindustryValvesValves areare ratedrated accordingaccording toto thethe maximummaximumpressurepressure andand temperaturetemperature atat whichwhich theythey cancan safelysafelybebe usedused..
Some API standard are :Some API standard are :
API 6DAPI 6D-- Pipe Line ValvePipe Line Valve
API 600API 600 –– Steel Gate ValveSteel Gate Valve
API 602API 602-- Carbon Steel Gate ValvesCarbon Steel Gate Valves
API 609API 609-- Butterfly ValvesButterfly Valves
Some BS standard are :Some BS standard are :
BS 1414BS 1414-- Gate Valve For Petroleum IndustryGate Valve For Petroleum Industry
BS 1868BS 1868-- Steel Check Valve For Petroleum IndustrySteel Check Valve For Petroleum Industry
BS 1673BS 1673-- Steel Globe Valve For Petroleum IndustrySteel Globe Valve For Petroleum Industry
BS 5155BS 5155-- Butterfly ValveButterfly Valve
BS 5351BS 5351-- Steel Ball ValveSteel Ball Valve
BS 5353BS 5353-- Carbon Steel And Alloy Steel Plug ValveCarbon Steel And Alloy Steel Plug Valve
VALVE TYPE SELECTION CRITERIA
Size limitations
Cost
,
pressure and flow rate
ServiceMaintenance requirements
VALVE STROKE(OPENNESS) VS THE
FLOW
Equal Percentage: equal increments of equal increments of valve travel produce an equal percentage invalve travel produce an equal percentage in
flowflow changechange
vave rave s rec y propor onavave rave s rec y propor ona
to the valve stoketo the valve stoke
Quick opening: large increase in flow withlarge increase in flow witha small change in valve strokea small change in valve stroke
Curve A = Quick Opening
VALVE CHARACTERISTICS
EQUAL-PERCENTAGE VALVE
LINEAR VALVE.
QUICK-OPENING VALVE.
Curve B = Linear
Curve C = Equal %
Equal Percentage (most commonly used valve control)Equal Percentage (most commonly used valve control)
Used in processes where large changes in pressure drop areUsed in processes where large changes in pressure drop are
expectedexpected
Used in processes where a small percentage of the totalUsed in processes where a small percentage of the totalpressure drop is permitted by the valvepressure drop is permitted by the valve
Used in temperature and pressure control loopsUsed in temperature and pressure control loops
LinearLinear
Used in liquid level or flow loopsUsed in liquid level or flow loops
Used in systems where the pressure drop across the valve isUsed in systems where the pressure drop across the valve is
expected to remain fairly constant (ie. steady state systems)expected to remain fairly constant (ie. steady state systems)
Quick OpeningQuick Opening
Used for frequent onUsed for frequent on--off serviceoff service
Used for processes where "instantly" large flow is neededUsed for processes where "instantly" large flow is needed
(ie.(ie. safety systems or cooling water systems)safety systems or cooling water systems)
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GATE VALVESGATE VALVESUsed when a tight shutUsed when a tight shut--off is required & there must beoff is required & there must bestraightstraight--line flow of fluid with min. resistanceline flow of fluid with min. resistance
Quick Opening valveQuick Opening valve
Infrequent operationInfrequent operation
Gate usually wedgeGate usually wedge--shaped or a vertical disc as in theshaped or a vertical disc as in thediagramdiagram
A lication: Oil as air slurries heav li uids steam noA lication: Oil as air slurries heav li uids steam no, , , , , ,, , , , , ,condensing gases, and corrosive liquidscondensing gases, and corrosive liquids
AdvAdv: high capacity,No flow restrictions & low cost: high capacity,No flow restrictions & low cost
DisadvDisadv::Poor throttlingPoor throttling
Cavitate at low pressure dropsCavitate at low pressure drops
Gate valves should not be used where frequent operation isGate valves should not be used where frequent operation is
requiredrequired
GATE VALVE
GATE OR DISCGATE OR DISC
BALL VALVEBALL VALVE
To provide a quick opening, linear & simple shutTo provide a quick opening, linear & simple shut--off off
For Fully open/closed, limitedFor Fully open/closed, limited--throttlingthrottling
Higher temperature fluidsHigher temperature fluids
Ball has opening through centre. when this opening is in line with the inlet &Ball has opening through centre. when this opening is in line with the inlet &outlet ports, flow will be allowed.when ball is turned through 90 deg. No flowoutlet ports, flow will be allowed.when ball is turned through 90 deg. No flowcan takes placecan takes place
Application: Normally found in seawater, sanitary, trim and drain, slurry andApplication: Normally found in seawater, sanitary, trim and drain, slurry andhydraulic systemshydraulic systems
AdvAdv::
OOffer minimum resistance to flow
Tight sealing with low torque
Low cost & High capacity
Low leakage and maintenanceOperation, reliability, durability, and capability of withstanding highpressures
DisadvDisadv::
Prone to cavitationsProne to cavitations
Not Suitable For Lines Subject To Pulasting FlowNot Suitable For Lines Subject To Pulasting Flow
Poor throttling characteristicsPoor throttling characteristics
ExpensiveExpensive
BALL VALVEBALL VALVE
BALLBALL
PLUG VALVEPLUG VALVE
To provide a quick, simple shutTo provide a quick, simple shut--off off
Not Common In Sizes Over 6 InchNot Common In Sizes Over 6 InchNot Suitable For Lines Subject To Pulasting FlowNot Suitable For Lines Subject To Pulasting Flow
Controls flow using a plug with a hole through it. PlugsControls flow using a plug with a hole through it. Plugs
can be made of rigid materials such as Tefloncan be made of rigid materials such as Teflon¨̈, making, making
t em ea or gt em ea or g --pur typur ty
AdvAdv::
Good for high pressure applicationsGood for high pressure applications
Easy to operate
Provide a tight shutoff
DisadvDisadv
Plugs may freeze if not operated for a long period
of time
PLUG VALVE
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DIAPHRAGM VALVE
For Low Pressure Corrosive Service As ShutFor Low Pressure Corrosive Service As Shut--off Valvesoff Valves
Diaphragm moves up and down to operate the valveDiaphragm moves up and down to operate the valve
Diaphragm materials available in Nitrile, Hypalon, Neoprene,Diaphragm materials available in Nitrile, Hypalon, Neoprene,PTFE, etc.PTFE, etc.
Application : Slurry Services, Suspended ParticlesApplication : Slurry Services, Suspended Particles (Elastomeric(ElastomericDiaphragm only)Diaphragm only) && Severe ChemicalSevere Chemical
A vA v::
Can Be Used Where Leakage Cannot Be ToleratedCan Be Used Where Leakage Cannot Be Tolerated
Disadv:Disadv:
Can Only Withstand A Maximum Operating Pressure 7 to 10Can Only Withstand A Maximum Operating Pressure 7 to 10Kg/CmKg/Cm22 gg
Require frequent maintenance as damage to diaphragmRequire frequent maintenance as damage to diaphragmoccuroccur
Cannot Withstand Temperature Above 400 Deg FCannot Withstand Temperature Above 400 Deg F
DIAPHRAGM VALVEDIAPHRAGM VALVE
Hand wheelHand wheelVisual I ndicatorVisual I ndicatorTravel StopTravel Stop
BonnetBonnet
DiaphragmDiaphragm
Compressor Compressor
Panel MountPanel MountProvisionProvision
One PieceOne Piece
Molded FlangeMolded Flange
GLOBE VALVES
Throttling service/flow regulation valveThrottling service/flow regulation valve
Linear and Equal percentage valveLinear and Equal percentage valve
Frequent operationFrequent operation
Application: steam, air, water, oil lines, corrosiveApplication: steam, air, water, oil lines, corrosivesubstances & slurriessubstances & slurries
Disc attached to valve stem rests against seat to shut off Disc attached to valve stem rests against seat to shut off flow of fluidflow of fluid
AdvAdv::
Efficient throttling & Accurate flow controlEfficient throttling & Accurate flow control
Available in multiple portsAvailable in multiple ports
DisadvDisadv::
flow resistanceflow resistance
High pressure dropHigh pressure drop
More expensive than other valvesMore expensive than other valves
GLOBE VALVE
NEEDLE VALVE
Most accurate flow control among the valvesMost accurate flow control among the valves
Similar To Globe Valve Except Disc Is Pointed At EndSimilar To Globe Valve Except Disc Is Pointed At End.Steel Valves Are Often Made From Bars stock Arc.Steel Valves Are Often Made From Bars stock ArcRugged.Rugged.
Valves 2 Inch. And Smaller For Use On Pilot Plants And Valves 2 Inch. And Smaller For Use On Pilot Plants AndBench Scale Equipment And Instrument Service .Bench Scale Equipment And Instrument Service .
Good For Manual Flow Control .GroundGood For Manual Flow Control .GroundJoint UnionJoint UnionBonnet Connection Preferable.Bonnet Connection Preferable.
Disadv:Disadv:
Positive ShutPositive Shut – –Off Not Always Posible OrOff Not Always Posible OrDesrible.Desrible.In some designs, seat is scored If ShutIn some designs, seat is scored If ShutDown TightlyDown Tightly
NEEDLE VALVE
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BUTTERFLY VALVESLinear, Equal percentage & & Positive shut –off quarter turn valve
Fully open/closed or throttling services
Frequent operation
Minimal fluid trapping in line
The disc or wafer rotates about a vertical axis & can be turned through 90deg. .The disc seals against the opening to cut of flow & can be positioned ata point between fully closed and fully opens as required
Application: Liquids, gases, slurries, liquids with suspended solids andventilation systems
Small, light-weight, easy operation ,low cost ,minimum maintenance,drip tight shut –off , quick-acting & reliability
High capacity, Low pressure drop& self-sealing so they don’trequire an additonal flange gasket for installation
Can be used for vacuum service
Disadv:High torque required for control
Prone to cavitations at lower flows
Leaks early & only low-flow throttle
The material used for seats restrict its use for high temperatureapplication
BUTTERFLY VALVE
CHECK VALVES
Allow flow in one direction only.Allow flow in one direction only.
Flow forces a ball or disk in one direction to open the valve;Flow forces a ball or disk in one direction to open the valve;
when flow stops, the ball or disk seats to close the valve.when flow stops, the ball or disk seats to close the valve.
An important concept in check valves is the crackingAn important concept in check valves is the cracking
pressure which is the minimum upstreampressure which is the minimum upstream pressure at whichat which
the valve will operate. Typically the check valve is designedthe valve will operate. Typically the check valve is designed
for and can therefore be specified for a specific crackingfor and can therefore be specified for a specific cracking
pressure.pressure.
One common application is in the discharge line of aOne common application is in the discharge line of a
centrifugal pump to prevent reverse suctioncentrifugal pump to prevent reverse suction
AdvAdv::
Check valves are automatic in actionCheck valves are automatic in action
CHECKVALVES:CHECKVALVES: HOW THEY
WORK…
CORRECT FLOW REVERSE FLOW
CHECK VALVE CLASSIFICATION
CHECK VALVE
SWING LIFT
PISTON LIFTWAFER BALL LIFT NON-SLAM
SWING CHECK
Controls direction of flowControls direction of flow
It has a hinged disk. When the water flowreverses, water pressure pushes the disk andcloses the valve
Application: Application: Suspended Particles,high velocitySuspended Particles,high velocity Adv Adv::
Minimum Pressure Drop is RequiredMinimum Pressure Drop is RequiredBest For Liquids And For Larger Line SizesBest For Liquids And For Larger Line Sizes(Above 2”)(Above 2”)
Disadv:Not Suitable In Line Subject To Pulsating FlowNot Suitable In Line Subject To Pulsating Flow
Some Styles Operates Only In A HorizontalSome Styles Operates Only In A HorizontalPositionPosition
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SWING-CHECK VALVE
WAFER CHECK VALVE
Wafer check valves are flangeless swing check valveWafer check valves are flangeless swing check valvecovered under regulatory code API 594covered under regulatory code API 594
Adv Adv::
,,reduced water hammer and are compactreduced water hammer and are compact
Disadv:Disadv:
producing relatively high head lossesproducing relatively high head losses
excessive wear under some operating conditionsexcessive wear under some operating conditions
WAFER CHECK VALVE PISTON LIFT CHECK VALVE
In a lift check valve, upward regular flow raisesthe piston and opens the valve, and reverseflow pushes the disk down to its seat and stopsthe backflow
vv::Good For Vapours ,Steam ,And Water.Good For Vapours ,Steam ,And Water.Suitable For Pulsating FlowSuitable For Pulsating Flow
Disadv:Many Design But For Horizontal Service Only.Many Design But For Horizontal Service Only.Not Common In Sizes Over 6 Inch.Not Common In Sizes Over 6 Inch.Not Recommended For Service Which DepositNot Recommended For Service Which DepositSolidsSolids
PISTON LIFT CHECK VALVEBALL LIFT CHECK VALVE
Controls direction of flowControls direction of flow
ball is located at end of stem and lifts to allow flowball is located at end of stem and lifts to allow flow Application: Space Limitation Problems, Minimum shut Application: Space Limitation Problems, Minimum shutoff is 5 psioff is 5 psi
Adv: Adv:Stop Flow Reversal More Rapidly Than OthersStop Flow Reversal More Rapidly Than Others
Good For Viscous Fluids Which Deposit SolidGood For Viscous Fluids Which Deposit SolidResidues That Would Impair Operation Of OtherResidues That Would Impair Operation Of Othertypetype
Vertical Or Horizontal Installation Is possible Vertical Or Horizontal Installation Is possibleDisadv:Disadv:
Not Common in Sizes Over 6 Inch.Not Common in Sizes Over 6 Inch.Not Suitable For Lines Subject To Pulsating FlowNot Suitable For Lines Subject To Pulsating Flow
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BALL LIFT CHECK VALVENON-SLAM CHECK VALVE
The NonThe Non--slam Check Valve Is A Springslam Check Valve Is A Spring--loadedloaded
Lift Check Valve With A Modified Design Of Lift Check Valve With A Modified Design Of
The BodyThe Body
The Valve Is Designed In Such Way That SameThe Valve Is Designed In Such Way That Same
Can Be Sandwiched Between The Two Flanges.Can Be Sandwiched Between The Two Flanges.
Here The Disc Is Held In Position By A SpringHere The Disc Is Held In Position By A Spring
Which Is Housed In A Housing Cap Or YokeWhich Is Housed In A Housing Cap Or Yoke
INSPECTION AND TESTING
Inspection plan to be submitted to Purchaser by supplierInspection plan to be submitted to Purchaser by supplierduring orderduring order
FOR FORGED VALVES/ CAST STEEL VALVESFOR FORGED VALVES/ CAST STEEL VALVES Visual and dimensional inspection. Visual and dimensional inspection.Review of material test certificates.Review of material test certificates.
Any mandatory of supplementary test. Any mandatory of supplementary test.Hydrostatic test of all valves.Hydrostatic test of all valves.Strip check on 1% of total ordered quantity of Strip check on 1% of total ordered quantity of valves at random to verify compliance withvalves at random to verify compliance withspecification requirementsspecification requirements
Review of radiographs / radiographic reports andReview of radiographs / radiographic reports andreports of any other NDT tests, for cast steel valvereports of any other NDT tests, for cast steel valveonlyonly
IBR VALVES
Valves described as “I BR Valves” shall be inValves described as “I BR Valves” shall be inaccordance wit h the lat est I BR (I ndian Boileraccordance wit h the lat est I BR (I ndian BoilerRegulations) as well as the ot her requirementsRegulations) as well as the ot her requirementsspecified in t he specification .specified in t he specification .
For SW / BW end carbon steel valves underFor SW / BW end carbon steel valves under “ ” “ ”,,shall conform to the following :shall conform to the following :
Carbon ( Max.)Carbon (Max.) :: 0.25%0.25%Others (S, P, Mn) :Others (S, P, Mn) : As per IBRAs per I BR
For all “IBR Valves” test certificate in form IIIFor all “IBR Valves” test certificate in form III--C shallC shallbe furnished, duly signed by IBR inspection authority orbe furnished, duly signed by IBR inspection authority oran IBR approved representativean IBR approved representative
All valves shall be painted red All valves shall be painted red
TERM USED FOR VALVE SPECIFIATION
PressurePressure – –t em per at ur e r at in gs:temperature ratings:
PressurePressure – –temperature rating is the maximum allowabletemperature rating is the maximum allowablesustained non shock pressure at the corresponding tabulatedsustained non shock pressure at the corresponding tabulatedtemperature. These are listed in ASME B16.34temperature. These are listed in ASME B16.34
Class:Class:
The valve is specified by the pressure rating of the body of The valve is specified by the pressure rating of the body of the valves. American Standard specified the following classesthe valves. American Standard specified the following classes(i.e. 150# ,300# ,400# ,600#,900# ,1500# & 2500 #)(i.e. 150# ,300# ,400# ,600#,900# ,1500# & 2500 #)
Trim:Trim:
The trim is comprised of stem ,seat surfaces ,back seatThe trim is comprised of stem ,seat surfaces ,back seatbushing and other small internal parts that’s normallybushing and other small internal parts that’s normallycontact the surface fluid.contact the surface fluid.
API 600 specifies trim number in table 3 of the standard ,it API 600 specifies trim number in table 3 of the standard ,itspecifies the types of material which can be used for thespecifies the types of material which can be used for theparts with its typical specification and grade.parts with its typical specification and grade.
TRIM PARTS OF COMMON VALVES
GATE GLOBE SWING LIFTCHECK
STEM STEM SEAT RING DISC GUIDE
SEAT RING SEAT RING DISC HOLDER SEAT RING
WEDGE RING DISC NUT SIDE PLUG
BUSHING BUSHING HOLDER PIN
DISC NUT PIN
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Wetted partsWetted parts:: All parts which come in contact with the service fluid are called the All parts which come in contact with the service fluid are called thewetted parts .wetted parts .
Wire drawingWire drawing::This term is used to indicate the premature erosion of the valve seatThis term is used to indicate the premature erosion of the valve seatcaused by excessive velocity between seat and seat disccaused by excessive velocity between seat and seat disc
A WOG (water A WOG (water --oiloil--gas, relatively cool liquids) disc is best defiancegas, relatively cool liquids) disc is best defianceagainst wire drawing because its resiliency make it easier to closeagainst wire drawing because its resiliency make it easier to closetightly.tightly.Stem discs are of harder material and to be closed carefully to preventStem discs are of harder material and to be closed carefully to preventwire drawingwire drawing
i i i ii i i i--i , i i ii , i i irefrigeration. The ice formation on the wedge will obstruct movementrefrigeration. The ice formation on the wedge will obstruct movementthereby increasing the leak through seat furtherthereby increasing the leak through seat further
StraightStraight – –t hr ough fl owthrough flow ::This refer to the valve in the closing element is retracted entirely sothat there is no restriction of flow
QuarterQuarter – –t ur n v alv e:turn valve:This refers to the valve where the entire operation of valve is achievedThis refers to the valve where the entire operation of valve is achievedby 90 deg. Turn of the closing elementby 90 deg. Turn of the closing element
UPSTREAM PRESSURE:UPSTREAM PRESSURE:
Pressure of the fluid entering the valve, sometimes refers toas inlet or supply pressure.
DOWNSTREAM PRESSURE:DOWNSTREAM PRESSURE:
Pressure of the fluid discharged from the valve, sometimesrefers to as outlet or reduced pressure.
LDAR:LDAR:
Signifies “ leak detection and repair” to ensure that theSignifies “ leak detection and repair” to ensure that thefugitive emission standards of EPA are met.fugitive emission standards of EPA are met.
LAER:LAER:
Signifies “ lowest achievable emission rate ” is the minimumSignifies “ lowest achievable emission rate ” is the minimumrate of fugitive emission which is achieved by deployingrate of fugitive emission which is achieved by deployingproper sealing arrangementsproper sealing arrangements