API机械密封冲洗方案课件

APIPipingPlansAPI冲洗方案November2004JCTianjinTrainingModule4.3SealEnvironment

密封环境1APIPipingPlansAPI冲洗方案Integral(internal)recirculationfrompumpdischargetoseal

Advantage-Noexternalpiping

Limitations-Changingflowraterequireddismantlingofpump-ForcleanpumpagesonlyAPIPipingPlansAPI冲洗方案PointstoNoteforAPIPlan11:-Useanorificetorestricttheflowrateifthedischargepressureis3barhigherthansealchamberpressure.-UseoncleanandlowabrasivesdutiesAPIPipingPlansAPI冲洗方案SealFlushingBy-PassfromDischarge单密封通过出口进行冲洗RecirculationfromsealchamberthroughaflowcontrolorificeandbacktopumpsuctionPointstoNoteforAPIPlan13:-Useanorificetorestricttheflowrateifthesealchamberpressureis3barhigherthansuctionpressure.-handleabrasivesdutybetterthanAPIplan11-highersealchamberpressuretosuppressvaporisationAPIPipingPlansAPI冲洗方案+=PointstoNoteforAPIPlan14:-Flowbacktosuctionsidewillevacuatevapoursthatmaycollectinsealchamber.-Recommendedforlighthydrocarbonservice.APIPipingPlansAPI冲洗方案RecirculationfrompumpdischargethroughaflowcontrolorificeandcoolertosealOpenLoopCoolingCircuitCoolingWaterOutletCoolingWaterInletAPIPipingPlansAPI冲洗方案PointstonoteforAPIPlan23:Thermosyphondesign

*heatexchanger18to24"abovepumpcentreline.*Preventoverheatinginstandbyandstart–up.Installclosefittingneckbushingatthebottomofsealchambertoisolatetheheatfromtheimpellerend.Usedonhightemperatureapplicationstominimiseheatloadonthecoolerbycoolingonlysmallamountofliquidthatisrecirculated.Forhightemperatureboilerfeedpumpapplications

Otherapplications

*hightemperatureliquidclosetobubblepoint.APIPipingPlansAPI冲洗方案PointstoNoteforAPIPlan32:-Choseapropersourceofsealflushtoeliminatethepotentialforvaporisationoftheinjectedfluidandtoavoidcontaminationofthefluidbeingpumpedwiththeinjectedflush.-Installalabyrinthbushingatthebottomofthestuffingboxtocontroltheflushingandpressureifnecessary.APIPipingPlansAPI冲洗方案SingleSealFlushingfromExternalSource单密封通过外部来源进行冲洗ThroatBushingNeedle

valveExternalreservoirprovidingadead-endedblanketoffluidtothequenchconnectionofthegland.

PointstoNoteforAPIPlan51:

--Deadendedblanketonatmosphericsideofsealtopreventfreezingofmoisture.Sealfacewillnotsticktogetherwhenthepumpstarted.

Typicalapplication:Pumpoperatingbelow0°C--API6108thEditionhaseliminatedthispipingplan.APIPipingPlansAPI冲洗方案PipingSystemsAPIPipingPlansAPI冲洗方案

Afluidusedasalubricantorbufferbetweendualmechanicalseals.Thebufferfluidisalwaysatapressurelowerthanthepumpprocesspressurebeingsealed.

Afluidwhichisintroducedbetweendualmechanicalsealstocompletelyisolatethepumpprocessliquidfromtheenvironment.Pressureofthebarrierfluidisalwayshigherthanthepumpprocesspressurebeingsealed.Thepurposeoffluidcirculation

istoremoveheatfrommechanicalsealAPIPipingPlansAPI冲洗方案PumpingringPump

Onapplicationsbelowambienttemperature,

circulationofbarrierfluidmaynotbedesirable.Theatmospherewillheatthereservoirand

consequentlyaddheattothesealarea.T2T1

Fluidcirculationbytemperaturedifferencebetweenthesealandreservoir.Highertemperatureliquidatsealhaslowerdensityrisestothereservoir.Lowertemperatureliquidatreservoirhashigherdensityfallstothesealtoprovidecooling.'ExternalForceCirculation''Thermosyphon''PumpingRing''DeadEnded'APIPipingPlansAPI冲洗方案PointstoNoteforAPIPlan52:TypicallyusedwithanArrangement2unpressuriseddualseal.Duringnormaloperation,circulationismaintainedbyaninternalpumpingring.Thereservoirisusuallycontinuouslyventedtoavapourrecoverysystemandismaintainedatapressurelessthanthepressureinthesealchamber.PressureGaugeLevelGaugeFillvalveOrificeDrainLevelSwitch(H)LevelSwitch(L)PressureSwitch(NormallyOpen)Ventvalve

Externalreservoirprovidingbufferfluidfortheoutersealofanunpressuriseddualsealarrangement.APIPipingPlansAPI冲洗方案PointstoNoteforAPIPlan54:TypicallyusedwithanArrangement3pressuriseddualseal.Duringnormaloperation,circulationismaintainedbyanexternalpumporpressuresystem.Thecirculatingbarrierfluidpressureisgreaterthantheprocesspressurebeingsealed.

ExternalbarrierfluidsystemprovidingpressurisedbarrierfluidfortheoutersealofanpressuriseddualsealarrangementAPIPipingPlansAPI冲洗方案Safetouse,handle,storeStableliquidatambienttemperaturesNotaVOC,VHAPorotherregulatedcompoundNonflammableNonfoamingwhenpressurisedCleanandgoodlubricityCompatiblewithprocessfluidCompatiblewithsealmaterialsGoodheattransferpropertiesGoodflowqualitiesatverylowtemperaturesLowsolubilityofgasLocalavailabilityLowcost

VOC:VolatileOrganicCompoundVHAP:VolatileHazardousAirPolutantsSelectionofBuffer/BarrierFluidAPIPipingPlansAPI冲洗方案PointstoNoteforAPIPlan62:Thequenchmayberequiredtopreventsolidsfromaccumulatingontheatmosphericsideoftheseal.Typicallyusedwithaclose-clearancethrottlebushing.APIPipingPlansAPI冲洗方案SingleSealQuenchfromExternalSource单密封通过外部急冷API6822ndEditionAPI682第二版

NewPipingPlans新的冲洗方案Plan14(Plan11+13)Plan53’s-Arrangement3,ContactingWet(CW)Seals53a–traditionalconfiguration53b–bladderaccumulator53c–pistonpot/accumulatorContainmentSealPlan72–Arrangement2w/ContainmentSeal(CS)Plan75–Arrangement2w/ContainmentSeal(CS)Plan76–Arrangement2w/ContainmentSeal(CS)GasBarrierSealsPlan74–Arrangement3,Non-Contacting(NC)SealsPlan53b

(A.4.12)Arrangement3,ContactingWet(CW)SealsDualPressurised(Double)SealsUtilizesbladderaccumulatorforpressureBladdereliminatesnitrogencontactwithbarrierliquidAllowsforhigherpressureapplicationsConfigurationIncludes:AccumulatorPressureIndicatorPressureSwitchHeatExchangerBIBOTIBIBOFWhenSpecifiedAPI6822ndEditionAPI682第二版

NewPipingPlans新的冲洗方案Plan53c

(A.4.12)Arrangement3,ContactingWet(CW)SealsDualPressurised(Double)SealsUtilizespistonpotforpressureBIBOBIBOFWhenSpecifiedAPI6822ndEditionAPI682第二版NewPipingPlans新的冲洗方案Plan53c

(A.4.12)AllowsforhigherpressureapplicationsConfigurationincludes:PistonpotPressureindicatorPressureswitchHeatexchangerLevelswitchPistonpoteliminatesnitrogencontactwithbarrierliquidPistonprovidesconstantpressureratiotoseals(1.1:1)SpringAPI6822ndEditionAPI682第二版NewPipingPlans新的冲洗方案Plan11withPlan53Arrangement3mayusePlan11&53ImprovedheattransferReversepressurecapability“BacktoBack”sealsusesPlan53API6822ndEditionAPI682第二版NewPipingPlans新的冲洗方案Plan72

(A.4.16)Arrangement2,w/ContainmentSeal(CS)DualUn-Pressurised(Tandem)SealsDry-runningsecondarycontainmentsealLowpressurenitrogensweep(purge)SweepsprimaryleakagetocollectionsystemDilutesprimaryleakagetoloweremissionlevelsUsedinconjunctionwithPlan75or76CSV:containmentsealventCSD:containmentsealDrainGBI:gasbufferinletFIL:coalescingfilterAPI6822ndEditionAPI682第二版NewPipingPlans新的冲洗方案Plan74

(A.4.17)Arrangement3,Non-contactingSeals(NC)DualPressurised(Double)GasBarrierSealsNitrogengasbarrier1.75-2bar(25-30psi)abovesealchamberpressureZeroemi