泵的振动英汉对照Word文件下载.docx

泵的振动英汉对照Word文件下载.docx

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∙Criticaldimensionsandtolerancessuchaswearringclearanceandimpellersettingwillbeaffectedbyvibration.Bearinginternalclearancesaremeasuredintenthsofthousandsofaninch.（thousandsofamillimeter）

∙Pumpcomponentscanbedamagedbyvibration.Wearrings,bushingsandimpellersarethreeexamples.

∙Bearingsealsareverysensitivetoshaftradialmovement.Shaftdamagewillincreaseandthesealswillfailprematurely.Labyrinthsealsoperatewithaveryclosetolerance.Excessivemovementcandamagethesetolerancesalso.

∙Pumpandmotorholddownboltscanbecomeloose.

Thevibrationcomesfromanumberofsourcesthatinclude:

Mechanicalcausesofvibration

∙Unbalancedrotatingcomponents.Damagedimpellersandnonconcentricshaftsleevesarecommon.

∙Abentorwarpedshaft.

∙Pumpanddrivermisalignment.

∙Pipestrain.Eitherbydesignorasaresultofthermalgrowth.

∙Themassofthepumpbaseistoosmall.

∙Thermalgrowthofvariouscomponents,especiallyshafts.

∙Rubbingparts.

∙Wornorloosebearings.

∙Looseholddownbolts.

∙Looseparts.

∙Damagedparts.

Hydrauliccausesofvibration

∙Operatingoffofthepump'

sbestefficiencypoint（BEP）

∙Vaporizationoftheproduct

∙Impellervanerunningtooclosetothepumpcutwater.

∙Internalrecirculation.

∙Airgettingintothesystemthroughvortexingetc..

∙Turbulenceinthesystem（non-laminarflow）.

∙Waterhammer.

Othercausesofvibration.

∙Harmonicvibrationfromnearbyequipment.

∙Operatingthepumpatacriticalspeed.Watchoutforthisprobleminvariablespeedandpulleydrivenpumps.

∙Seal"

slipstick"

atthesealfaces.Thiscanoccurifyouarepumpinganon-lubricatingfluid,agasoradrysolid.

∙Apumpdischargerecirculationlineaimedatthesealfaces.

MechanicalProblemSolutions

∙Balanceallofyourrotatingequipment.Ifyoudonothavedynamicbalancingequipmentinyourplanttherearecontractorsandvendorsanxioustoworkwithyou.Balanceisalwaysaproblemwhenyou'

repumpingabrasives,oraslurry,becausetherapidwearalwaysdestroysbalance.Inthehigherspeedpumpsthiswearcanbeverysevere.

∙Bentshaftsareaproblem.Ifyoucanstraightenthemgoaheadanddoit,butmostattemptsareunsuccessful.Inthemajorityofcasesyouarebetteroffreplacingtheshaft.

∙Doaproperpump/driveralignmentusingeitheralaserorthereverseindicatormethod.Upgradingthepumppowerendtoa"

C"

or"

D"

framemotoradapterisamoresensibleandeconomicaldecision.Oncetheconversionismademisalignmentceasestobeaconcern.Theseadaptersareavailableformostmotorsandwillmaintaintheproperalignmentastheequipmentgoesthroughitsnormaltemperaturetransients.

∙Alwayspipefromthepumpsuctiontothepiperack,nevertheotherway.Therearesomemorepipingpracticesthatyoushouldfollow:

oIfyouareexperiencingpipestrainbecauseofthermalgrowthatthesuction,youmightconverttoa"

centerline"

designwetendandsolvetheproblem.Centerlinedesignsmakesenseanytimeyouarepumpingafluidinexcessof200degreesFahrenheit（100Centigrade）

oTrytouseatleasttendiametersofpipebetweenthepumpsuctionandthefirstelbow.

oPipesupportsandhangersshouldbeinstalledatunequaldistances..

oUselotsofhangerstosupportthepiping.

oUselotsofloopsandexpansionjointsinthepipingsystem.

oAfterfabricationandtesting,removeallsupportsandlockpinsfromthespringhangers,loosenpipeflangesandadjustthesystemtofreethepumpfrompipestrain.

oReferencethe"

HydraulicInstituteManual"

orasimilarpublicationtolearnthepropermethodsofpipingseveralpumpsfromthesamesuctionsourcetopreventvortexingetc..

∙Themassofthepumpconcretefoundationshouldbefivetimesthemassofthepump,baseplateandotherequipmentbeingsupported.

∙Thefoundationshouldbethreeinches（75mm）widerthanthebaseplate,allaround,upto500horsepower（375KW）andsixinches（150mm）above500horsepower（375KW）.

∙Imaginarylines,extendeddownward30degreestoeithersideofaverticalthroughthepumpshaft,shouldpassthroughthebottomofthefoundationandnotthesides.

∙Everyinchofstainlesssteelgrows0.001inchforevery100°

Fahrenheitriseintemperature（0,001mm/mm/50°

Centigrade）Thisthermalgrowthcancausetheimpellertorubthepumpcasingaswellascauserubbinginmanyclosetoleranceclearancessuchasthewearrings.Carbonsteelgrowsabout30%lessthanstainlesssteel.

∙Anytimetheshaftmovesthereisthedangerofpartsrubbing.Thermalimagingequipmentcandetectthisrubbingeasily.Wheneveryousettighttolerancesbesuretoallowforthermalgrowthand,inthecaseofA.N.S.I.pumps,impelleradjustment.

∙Wornorloosebearingsarecausedbyimproperinstallationorallowingwatertoenterthebearingcavity.Labyrinthsealsorpositivefacesealsaretheeasiestsolutiontothewaterproblem.Installbearingsbyusingaproperinductionheatertopreventcontaminationduringtheinstallationprocess.

∙Theanswertolooseholddownboltsisobviousandrequiresnoexplanation.

HydraulicProblemSolutions

∙YoumaybeabletoincreaseorreducetheimpellerdiametertogetclosetothepumpB.E.P.,butifthisisnotpracticalyourbestbetistoreducetheL3/D4bygoingtoasolidshaftorupgradingthepowerendtoalargershaftdiameter.Insomeinstancesyoucaninstallasupportbushinginthebottomofthepackingstuffingboxandinstallamechanicalsealclosertothebearings.Splitsealsareidealforthisconversion.Inafewinstances,changingtheshaftspeedwillsolvetheproblem.Aclosedloopsystemwithahighsystemheadisanidealcandidateforavariablespeedpump

∙InsurethatyouhaveenoughNPSHforyourapplication.Ifthereisn'

tenough,aninducerorboosterpumpmightsolvetheproblem.

∙Animpeller,runningtooclosetothepumpcutwaterwillcausevibrationanddamage.Animpellertiptocutwaterclearanceof4%（oftheimpellerdiameter）inthesmallerimpellersizes（to14inch/355mm）and6%inthelargersizeswillsolvethisproblem.Thisbecomesaproblemwithmostselfprimingpumpsandtheonlysolutionistocontactyourpumpsupplierforhisrecommendation,ifhehasone.Repairedimpellerssometimesexperiencethisproblem.

∙Internalrecirculationproblemscanbesolvedbyeitheradjustingtheopenimpellerorreplacingtheclosedimpellerwithanalternativedesign.Thisproblemwasdiscussedinanothervolumeofthistechnicalseries.

∙Aircangetintoasystemthroughvalvesabovethewaterlineorflanges,buttheeasiestwayforairtoenterasystemisthroughthestuffingboxofapackedpump.Thesimplestsolutionistoreplacethepumppackingwithabalancedo-ringseal.Ifvortexingistheproblem,consultthe"

forinformationonvortexbreakersandproperpipinglayoutstopreventturbulenceinthelines,andatthepumpsuction.

∙Waterhammerisnotverywellunderstoodbyourindustry,butweknowhowimportantitistokeepairoutofthepipingsystem.

∙It'

sgoodpracticetouseonesizelargersuctionpipeandthenuseareducertoconnectthepipingtothepump.Donotuseconcentricreducers.Eccentrictypesaremuchbetter,aslongasyoudonotinstallthemupsidedown.

Solutionstoothertypesofvibration

∙Thepump,oroneofitscomponents,canvibrateinharmonywithanotherpieceofequipmentlocatedincloseproximity.Isolation,byvibrationdamping,istheeasiestsolutiontothisproblem.Thisisabigproblemwithmanymetalbellowssealdesignsbecausetheyarelackinganelastomerthatfunctionsasavibrationdamper.

∙Criticalspeedoperationisnotacommonproblemunlessyou'

reoperatingwithavariablespeeddrive.Changingthespeedistheobvioussolution.Ifthat'

snotpractical,changingtheimpellerdiameterisanothersolution.

slipstick"

isaproblemwithnonlubricantssuchashotwaterormostsolvents.Ifyou'

reusingo-ringseals,theo-ringisanaturalvibrationdamper.Metalbellowssealsrequirethataseparatevibrationdamperbeinstalled;

usuallyintheformofametalcomponentvibratingandslidingontheshaft.

∙Pumpdischargerecirculationlinescancauseavibrationeverytimetheimpellerpassestherecirculationline"

tapoff"

.Thisvibrationwillaffectthemechanicalsealandlikeallvibration,canberecognizedbychippingontheoutsidediameterofthecarbonfaceandworndrivelugs.

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