eccentric reducers and straight runs of pipe at pump suction _ hydrocarbon processing _ september...
DESCRIPTION
Why eccentric reducers are used in pump suction? clear explanationTRANSCRIPT
COPYINGANDDISTRIBUTINGAREPROHIBITEDWITHOUTPERMISSIONOFTHEPUBLISHEREccentricreducersandstraightrunsofpipeatpumpsuction09.01.2010|Bloch,H.P.,HydrocarbonProcessingStaff,Keywords:[pumps][piping][maintenance]Questionsrelatingtoproperreducerapplicationincentrifugalpumpsuctionlinesdatebackmanydecades.Untilhisdeath(atage84,in1995),worldrenownedpumpexpertIgorKarassikfrequentlycorrespondedwiththewriterandotherpumpusersonpumprelatedsubjects.Werarelypassupanopportunitytohighlightsomeofhisexperiencebasedcomments.Once,apumpuserreferredtoFig.1andnotedthatthiswasquitetypicalofillustrationsfoundinmanytextbooks.Inessence,Fig.1indicatesthat,withasuctionlineenteringthepumpinthehorizontalplane,theeccentricreducerisplacedwiththeflatatthetop.Availabletextsoftengivenoindicationastowhetherthepumpagecamefromaboveorbelowthepump.Fig.1.IllustrationofeccentricreducermountingfromHydraulicInstituteStandards.IgorKarassikagreedthat,ifthesupplysourcewasfromabovethepump,theeccentricreducershouldbeinstalledwiththeflat(horizontal)surfaceatthebottom.Entrainedvaporbubblescouldthenmigratebackintothesourceinsteadofstayingnearthepumpsuction.Ifthepumpsuctionpipingenteredafteralonghorizontalrunorfrombelowthepump,theflatoftheeccentricreducershouldbeatthetop.1Still,inmanyoldertextsithasbeenassumedthatthepumpagesourceoriginatedatalevelbelowthepumpsuctionnozzle.KarassikremindedusthatolderHydraulicInstituteStandardscommentedonthesuctionpipeslope:...Anyhighpointinthesuctionpipewillbecomefilledwithairandthuspreventproperoperationofthepump.Astraighttaperreducershouldnotbeusedinahorizontalsuctionlineasanairpocketisformedinthetopofthereducerandthepipe.Aneccentricreducershouldbeusedinstead.Thisinstructionappliesregardlessofwherethepumpageoriginates.Dependingontheparticularsofaninstallation,trappedvaporscanreducetheeffectivesuctionlinecrosssectionalarea.Shouldthatbethecase,flowvelocitieswouldtendtobehigherthananticipated.Higherfrictionlosseswouldoccurandpumpperformancewouldbeadverselyaffected.Inthecaseofaliquidsourceabovethepumpsuction,andparticularlywherethesuctionlineconsistsofaneccentricreducerfollowedbyanelbowturnedverticallyupwardandaverticalpipelengthallassembledinthatsequencefromthepumpsuctionflangeupstreamitwillbemandatoryfortheeccentricreducerflatsidetobeatthebottom.Thatsaid,Fig.2shouldclarifywhatreliabilityfocusedusersneedtoimplement.Fig.2.Suggestedmodificationsforeccentricreducermountings.Also,whenevervaporsmustbeventedagainsttheflowdirection,thelinesizeupstreamofanylowpointmustbegovernedbyanimportantcriterion.Thelinemustbeadiameterthatwilllimitthepumpagevelocitytovaluesbelowthosewherebubbleswillrisethroughtheliquid.Ingeneral,itcanbestatedthatwhereveralowpointexistsinasuctionline,thehorizontalpipingrunatthatpointshouldbekeptasshortaspossible.Inaproperinstallation,thereducerflangewillthusbelocatedatthepumpsuctionnozzleandthereisusuallynostraightpipingbetweenreduceroutletandpumpnozzle.Straightpipelengthsare,however,connectedtotheeccentricreducerinletflange.Onmostpumps,oneusuallygetsawaywithfivediametersofstraightlengthnexttothereducer.Inthecaseofcertainunspecifiedvelocitiesandotherinteractingvariables(e.g.,viscosity,NPSHmargin,pumpstyle,etc.),itmightbewisetoinstallasmanyas10diametersofstraightlengthnexttothereducerinletflange.Thetwodifferentrulesofthumbexplainseeminginconsistenciesintheliterature,whereboththe5and10Drulescanbefound.HPLITERATURECITED1Karassik,IgorJ.,CentrifugalPumpClinic,2ndEd.,MarcelDekker,Inc.,1989.TheauthorHeinzP.BlochisHPsEquipment/ReliabilityEditor.Theauthorof17textbooksandover470papersorarticles,headvisesprocessplantsworldwideonreliabilityimprovementandmaintenancecostreductionopportunities.HiscoauthoredBloch/Budristext,PumpUsersHandbook,iscomprehensiveandverywidelyused.Findthe2ndeditionunderISBN0881735175.HecanbecontactedatHB@HydrocarbonProcessing.com.DharmendraPatel06.18.2015amalraj06.11.2015rhenomaestrado05.28.2015rhenomaestrado05.28.2015LalitKumar05.04.2015Antony01.28.2015ali06.06.2014ManishJoshi05.19.2014susheel05.12.2014pipingdesigners.com03.25.2014Abdul03.14.201401.08.2014PradipSinha01.08.2014AbidBhatti11.06.2013Mohamedmetawa08.25.2013varun06.13.2013akshay01.05.2013Asperliteraturecited,positionofflatlineofeccentricreducerdependsonnatureoffluidhandled!ThevaporshandleneartodewpointbyCentri.MCsequipedwithflat(horizontal)surfaceatTOPwhereasfluidhandlesneartobubblepointequipedwithflatsurfaceatBOTTOM!TheCentri.MCstobeinterpretedasBLOWERorPUMPasperfluidapplication!whatistheclearanceofeccentric&concentricforsuctionanddischargepiperouting?iwanttoseetheimagesofareducerlikeeccentricwhyuseeccentricreducerinpumpsuctionline?Wanttoknowhowtomanufactureeccentricreducerorproductionprocess.AndformulatocalculatelayoutofmaterialrequiredThisarticleisreallyniceanditclearssomemyth.Formoredetailaboutpumppipingathttp://pipinginfo.blogspot.ca/2011/02/pumppipinglayoutdesignguidelines.htmlwhyuseeccentricreducerinpumpsuctionlineSomeoftheEPCsusingastandardwheretheyuseecentricreduceratPumpsuctionwithflatsidealwaysatthetop.Veryvaluablereferencetoaskthemtobeflexiblewiththeirstandardifthepumpageisfromabovethepump.Thanksforbringingthisclarity!!Eccentricareplacedflatsidedowninline.Greatarticle...IhavearguedthispointwithengineerswhoINSISTthatareducershallbeplacedflatsideup,regardlessofthesourceofthepumpage.ConsiderthisarticleBOOKMARKED!IknowI'llbepullingitoutforreference.Canweuseeccentricreducerinsteadofconcentricreducerifwedowhatwillbetheeffectisthereanydisadvantage?...CozoneofthefitterhadusedeccentricinsteadofconcentricinPSVconnection.UppersideBigDiaLowersideSmallDiaPleasesuggestiwanttoknowthattheuseofconcentricandeccentricreducer.wehave8noshighpressurepump(capacity156m3/hr,max.pressure15kg/cm2)withasinglesuctionheader.So,everymonthoneofthempumpshaftisbeingdamaged.Iwantsolution.Thanksforveryhelpfullarticle.thanksalot.AstowhytheeccentricreducershouldbemountedwithflatbottomatbottomforpumpageSourceabovepumpsuctionisstillveryuncleartome..KindlyelaboratethesameDear,whatbenefitsofeccentricreducerwith1",2"pipeatsuctionofCFpump?alsowhichtypeofmaterialservice¶meterrequiredinpump(Viscocity,spe.gravity)aremoresuitableforeccentricreducer?Mr.Piper00708.30.2012mojtabajavan06.11.2012CHARLES02.09.2012Shankar12.10.201102.28.201109.23.201009.21.201009.20.2010isthereanypossibilitythatconcentricreducersbeusedonhorizontallinepiping?tanksforthispaper.www.mojtabajavan.irThanxforyourinfo.Nowiknow.RegardsWhyshouldprovidetheeccentricreducerinthepumpsuctionandwhynotprovideconcentricreducer????......ifanyspecialpurposeofprovidingtheeccentric????......plsgivesuggestion.....AstowhytheeccentricreducershouldbemountedwithflatbottomatbottomforpumpageSourceabovepumpsuctionisstillveryuncleartome..Kindlyelaboratethesame.RgdsAnirbanDearSir,Pleasealsoincludesomeguidelinefor(1)straightlengthrequirementforvarioustypesofPumpsi.e.OH2/BB1/BB2/MultistagePumpsandfortypeofSuctioni.e.single/doublesuction(2)IfduetoLayoutconstraincanwegofor3DstratghtlengthforsuctionWaitngforyourreplyThanks,KiranThankGodyouclarified.Thereareinnumerablereferences&bookspropagatingtheincorrectreducerconnectionAndtheremustbemillionsofincorrectinstallations.Iasaprojectman(nonMech.)andgoingbybasicprincipalshadarguedwithPumpspecialistsoverthisanomalywhenapumpwasmisbehavingbutwasshownthetextbook.IhadthepriviledgetoattendapumpingproblemsclassledbyIgorKarrasik.Istillhavethecoursenotesandhaveusedthemforover30+years.PleasereadourTermandConditionsandPrivacyPolicybeforeusingthesite.Allmaterialsubjecttostrictlyenforcedcopyrightlaws.2015HydrocarbonProcessing.2015GulfPublishingCompany.