ISO--国际标准化组织\ISO 5167-4-2003

INTERNATIONALISOSTANDARD5167-4Firstedition2003-03-01Measurementoffluidflowbymeansofpressuredifferentialdevicesinsertedincircularcross-sectionconduitsrunningfull—Part4:VenturitubesMesurededébitdesfluidesaumoyend'appareilsdéprimogènesinsérésdansdesconduitesenchargedesectioncirculaire—Partie4:TubesdeVenturi--```,``-`-`,,`,,`,`,,`---ReferencenumberISO5167-4:2003(E)CopyrightInternationalOrganizationforStandardization©ISO2003ReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleISO5167-4:2003(E)PDFdisclaimerThisPDFfilemaycontainembeddedtypefaces.InaccordancewithAdobe'slicensingpolicy,thisfilemaybeprintedorviewedbutshallnotbeeditedunlessthetypefaceswhichareembeddedarelicensedtoandinstalledonthecomputerperformingtheediting.Indownloadingthisfile,partiesacceptthereintheresponsibilityofnotinfringingAdobe'slicensingpolicy.TheISOCentralSecretariatacceptsnoliabilityinthisarea.AdobeisatrademarkofAdobeSystemsIncorporated.DetailsofthesoftwareproductsusedtocreatethisPDFfilecanbefoundintheGeneralInforelativetothefile;thePDF-creationparameterswereoptimizedforprinting.EverycarehasbeentakentoensurethatthefileissuitableforusebyISOmemberbodies.Intheunlikelyeventthataproblemrelatingtoitisfound,pleaseinformtheCentralSecretariatattheaddressgivenbelow.©ISO2003Allrightsreserved.Unlessotherwisespecified,nopartofthispublicationmaybereproducedorutilizedinanyformorbyanymeans,electronicormechanical,includingphotocopyingandmicrofilm,withoutpermissioninwritingfromeitherISOattheaddressbeloworISO'smemberbodyinthecountryoftherequester.ISOcopyrightofficeCasepostale56•CH-1211Geneva20Tel.+41227490111Fax+41227490947E-mailcopyright@iso.orgWebwww.iso.orgPublishedinSwitzerland--```,``-`-`,,`,,`,`,,`---CopyrightInternationaliiOrganizationforStandardization©ISO2003—AllrightsreservedReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleISO5167-4:2003(E)ContentsPageForeword............................................................................................................................................................ivIntroduction........................................................................................................................................................v1Scope......................................................................................................................................................12Normativereferences...........................................................................................................................23Termsanddefinitions...........................................................................................................................24Principlesofthemethodofmeasurementandcomputation...........................................................25ClassicalVenturitubes.........................................................................................................................35.1Fieldofapplication...............................................................................................................................35.2Generalshape.......................................................................................................................................35.3Materialandmanufacture.....................................................................................................................75.4Pressuretappings.................................................................................................................................75.5Dischargecoefficient,C.......................................................................................................................85.6Expansibility[expansion]factor,ε......................................................................................................95.7UncertaintyofthedischargecoefficientC.......................................................................................105.8Uncertaintyoftheexpansibility[expansion]factorε......................................................................105.9Pressureloss.......................................................................................................................................106Installationrequirements...................................................................................................................116.1General.................................................................................................................................................116.2MinimumupstreamanddownstreamstraightlengthsforinstallationbetweenvariousfittingsandtheVenturitube..............................................................................................................116.3Flowconditioners...............................................................................................................................156.4AdditionalspecificinstallationrequirementsforclassicalVenturitubes....................................15AnnexA(informative)Tableofexpansibility[expansion]factor................................................................17AnnexB(informative)ClassicalVenturitubesusedoutsidethescopeofISO5167-4.............................18AnnexC(informative)PressurelossinaclassicalVenturitube................................................................22Bibliography.....................................................................................................................................................24--```,``-`-`,,`,,`,`,,`---CopyrightInternationalOrganization©ISOfor2003Standardization—AllrightsreservediiiReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleISO5167-4:2003(E)ForewordISO(theInternationalOrganizationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISOmemberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnicalcommittees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhastherighttoberepresentedonthatcommittee.Internationalorganizations,governmentalandnon-governmental,inliaisonwithISO,alsotakepartinthework.ISOcollaboratescloselywiththeInternationalElectrotechnicalCommission(IEC)onallmattersofelectrotechnicalstandardization.InternationalStandardsaredraftedinaccordancewiththerulesgivenintheISO/IECDirectives,Part2.ThemaintaskoftechnicalcommitteesistoprepareInternationalStandards.DraftInternationalStandardsadoptedbythetechnicalcommitteesarecirculatedtothememberbodiesforvoting.PublicationasanInternationalStandardrequiresapprovalbyatleast75%ofthememberbodiescastingavote.Attentionisdrawntothepossibilitythatsomeoftheelementsofthisdocumentmaybethesubjectofpatentrights.ISOshallnotbeheldresponsibleforidentifyinganyorallsuchpatentrights.ISO5167-4waspreparedbyTechnicalCommitteeISO/TC30,Measurementoffluidflowinclosedconduits,SubcommitteeSC2,Pressuredifferentialdevices.ThisfirsteditionofISO5167-4,togetherwiththesecondeditionofISO5167-1andthefirsteditionsofISO5167-2andISO5167-3,cancelsandreplacesthefirsteditionofISO5167-1:1991,whichhasbeentechnicallyrevised,andISO5167-1:1991/Amd.1:1998.ISO5167consistsofthefollowingparts,underthegeneraltitleMeasurementoffluidflowbymeansofpressuredifferentialdevicesinsertedincircularcross-sectionconduitsrunningfull:Part1:GeneralprinciplesandrequirementsPart2:OrificeplatesPart3:NozzlesandVenturinozzlesPart4:Venturitubes--```,``-`-`,,`,,`,`,,`---CopyrightInternationalivOrganizationforStandardization©ISO2003—AllrightsreservedReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleISO5167-4:2003(E)IntroductionISO5167,dividedintofourparts,coversthegeometryandmethodofuse(installationandoperatingconditions)oforificeplates,nozzlesandVenturitubeswhentheyareinsertedinaconduitrunningfulltodeterminetheflowrateofthefluidflowingintheconduit.Italsogivesnecessaryinformationforcalculatingtheflowrateanditsassociateduncertainty.--```,``-`-`,,`,,`,`,,`---ISO5167isapplicableonlytopressuredifferentialdevicesinwhichtheflowremainssubsonicthroughoutthemeasuringsectionandwherethefluidcanbeconsideredassingle-phase,butisnotapplicabletothemeasurementofpulsatingflow.Furthermore,eachofthesedevicescanonlybeusedwithinspecifiedlimitsofpipesizeandReynoldsnumber.ISO5167dealswithdevicesforwhichdirectcalibrationexperimentshavebeenmade,sufficientinnumber,spreadandqualitytoenablecoherentsystemsofapplicationtobebasedontheirresultsandcoefficientstobegivenwithcertainpredictablelimitsofuncertainty.Thedevicesintroducedintothepipearecalled“primarydevices”.Thetermprimarydevicealsoincludesthepressuretappings.Allotherinstrumentsordevicesrequiredforthemeasurementareknownas“secondarydevices”.ISO5167coversprimarydevices;secondarydevices1)willbementionedonlyoccasionally.ISO5167isdividedintothefollowingfourparts.a)Part1ofISO5167givesgeneraltermsanddefinitions,symbols,principlesandrequirementsaswellasmethodsofmeasurementanduncertaintythataretobeusedinconjunctionwithParts2to4ofISO5167.b)Part2ofISO5167specifiesorificeplates,whichcanbeusedwithcornerpressuretappings,DandD/2pressuretappings2),andflangepressuretappings.c)Part3ofISO5167specifiesISA1932nozzles3),longradiusnozzlesandVenturinozzles,whichdifferinshapeandinthepositionofthepressuretappings.d)ThispartofISO5167specifiesclassicalVenturitubes4).AspectsofsafetyarenotdealtwithinParts1to4ofISO5167.Itistheresponsibilityoftheusertoensurethatthesystemmeetsapplicablesafetyregulations.1)SeeISO2186:1973,Fluidflowinclosedconduits—Connectionsforpressuresignaltransmissionsbetweenprimaryandsecondaryelements.2)Orificeplateswith“venacontracta”pressuretappingsarenotconsideredinISO5167.3)ISAistheabbreviationfortheInternationalFederationoftheNationalStandardizingAssociations,whichwassucceededbyISOin1946.4)IntheUSAtheclassicalVenturitubeissometimescalledtheHerschelVenturitube.CopyrightInternationalOrganization©ISOfor2003Standardization—AllrightsreservedvReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResale--```,``-`-`,,`,,`,`,,`---CopyrightInternationalOrganizationforStandardizationReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleINTERNATIONALSTANDARDISO5167-4:2003(E)Measurementoffluidflowbymeansofpressuredifferentialdevicesinsertedincircularcross-sectionconduitsrunningfull—Part4:Venturitubes1ScopeThispartofISO5167specifiesthegeometryandmethodofuse(installationandoperatingconditions)ofVenturitubeswhentheyareinsertedinaconduitrunningfulltodeterminetheflowrateofthefluidflowingintheconduit.--```,``-`-`,,`,,`,`,,`---ThispartofISO5167alsoprovidesbackgroundinformationforcalculatingtheflowrateandisapplicableinconjunctionwiththerequirementsgiveninISO5167-1.ThispartofISO5167isapplicableonlytoVenturitubesinwhichtheflowremainssubsonicthroughoutthemeasuringsectionandwherethefluidcanbeconsideredassingle-phase.Inaddition,eachofthesedevicescanonlybeusedwithinspecifiedlimitsofpipesize,roughness,diameterratioandReynoldsnumber.ThispartofISO5167isnotapplicabletothemeasurementofpulsatingflow.ItdoesnotcovertheuseofVenturitubesinpipessizedlessthan50mmormorethan1200mm,orwherethepipeReynoldsnumbersarebelow2×105.ThispartofISO5167dealswiththethreetypesofclassicalVenturitubes:a)cast;b)machined;c)roughweldedsheet-iron.AVenturitubeisadevicewhichconsistsofaconvergentinletconnectedtoacylindricalthroatwhichisinturnconnectedtoaconicalexpandingsectioncalledthe“divergent”.ThedifferencesbetweenthevaluesoftheuncertaintyofthedischargecoefficientforthethreetypesofclassicalVenturitubeshow,ontheonehand,thenumberofresultsavailableforeachtypeofclassicalVenturitubeand,ontheotherhand,themoreorlessprecisedefinitionofthegeometricprofile.Thevaluesarebasedondatacollectedmanyyearsago.Venturinozzles(andothernozzles)aredealtwithinISO5167-3.NOTE1ResearchintotheuseofVenturitubesinhigh-pressuregas[W1MPa(W10bar)]isbeingcarriedoutatpresent(seeReferences[1],[2],[3]intheBibliography).InmanycasesforVenturitubeswithmachinedconvergentsectionsdischargecoefficientswhichlieoutsidetherangepredictedbythispartofISO5167by2%ormorehavebeenfound.ForoptimumaccuracyVenturitubesforuseingasshouldbecalibratedovertherequiredflowraterange.Inhigh-pressuregastheuseofsingletappings(oratmosttwotappingsineachplane)isnotuncommon.NOTE2IntheUSAtheclassicalVenturitubeissometimescalledtheHerschelVenturitube.CopyrightInternationalOrganization©ISOfor2003Standardization—Allrightsreserved1ReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleISO5167-4:2003(E)2NormativereferencesThefollowingreferenceddocumentsareindispensablefortheapplicationofthisdocument.Fordatedreferences,onlytheeditioncitedapplies.Forundatedreferences,thelatesteditionofthereferenceddocument(includinganyamendments)applies.ISO4006:1991,Measurementoffluidflowinclosedconduits—VocabularyandsymbolsISO5167-1:2003,Measurementoffluidflowbymeansofpressuredifferentialdevicesinsertedincircularcross-sectionconduitsrunningfull—Part1:Generalprinciplesandrequirements3TermsanddefinitionsForthepurposesofthisdocument,thetermsanddefinitionsgiveninISO4006andISO5167-1apply.4PrinciplesofthemethodofmeasurementandcomputationTheprincipleofthemethodofmeasurementisbasedontheinstallationofaVenturitubeintoapipelineinwhichafluidisrunningfull.InaVenturitubeastaticpressuredifferenceexistsbetweentheupstreamsectionandthethroatsectionofthedevice.Wheneverthedeviceisgeometricallysimilartooneonwhichdirectcalibrationhasbeenmade,theconditionsofusebeingthesame,theflowratecanbedeterminedfromthemeasuredvalueofthispressuredifferenceandfromaknowledgeofthefluidconditions.Themassflowratecanbedeterminedbythefollowingformula:Cπ2qdpm=∆ερ21(1)1−β44TheuncertaintylimitscanbecalculatedusingtheproceduregiveninClause8ofISO5167-1:2003.Similarly,thevalueofthevolumeflowratecanbecalculatedsinceqq=mVρwhereρisthefluiddensityatthetemperatureandpressureforwhichthevolumeisstated.Computationoftheflowrate,whichisapurelyarithmeticprocess,isperformedbyreplacingthedifferentitemsontheright-handsideofEquation(1)bytheirnumericalvalues.TableA.1givesVenturitubeexpansibilityfactors(ε).Theyarenotintendedforpreciseinterpolation.Extrapolationisnotpermitted.ThediametersdandDmentionedinEquation(1)arethevaluesofthediametersatworkingconditions.Measurementstakenatanyotherconditionsshouldbecorrectedforanypossibleexpansionorcontractionoftheprimarydeviceandthepipeduetothevaluesofthetemperatureandpressureofthefluidduringthemeasurement.Itisnecessarytoknowthedensityandtheviscosityofthefluidatworkingconditions.Inthecaseofacompressiblefluid,itisalsonecessarytoknowtheisentropicexponentofthefluidatworkingconditions.--```,``-`-`,,`,,`,`,,`---CopyrightInternational2OrganizationforStandardization©ISO2003—AllrightsreservedReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleISO5167-4:2003(E)5ClassicalVenturitubes5.1Fieldofapplication5.1.1GeneralThefieldofapplicationoftheclassicalVenturitubesdealtwithinthispartofISO5167dependsonthewayinwhichtheyaremanufactured.ThreetypesofstandardclassicalVenturitubearedefinedaccordingtothemethodofmanufactureoftheinternalsurfaceoftheentranceconeandtheprofileattheintersectionoftheentranceconeandthethroat.Thesethreemethodsofmanufacturearedescribedin5.1.2to5.1.4andhavesomewhatdifferentcharacteristics.TherearelimitstotheroughnessandReynoldsnumberforeachtypewhichshallbeaddressed.5.1.2ClassicalVenturitubewithan“ascast”convergentsectionThisisaclassicalVenturitubemadebycastinginasandmould,orbyothermethodswhichleaveafinishonthesurfaceoftheconvergentsectionsimilartothatproducedbysandcasting.Thethroatismachinedandthejunctionsbetweenthecylindersandconesarerounded.TheseclassicalVenturitubescanbeusedinpipesofdiameterbetween100mmand800mmandwithdiameterratiosβbetween0,3and0,75inclusive.5.1.3ClassicalVenturitubewithamachinedconvergentsectionThisisaclassicalVenturitubecastorfabricatedasin5.1.2butinwhichtheconvergentsectionismachinedasarethethroatandtheentrancecylinder.Thejunctionsbetweenthecylindersandconesmayormaynotberounded.TheseclassicalVenturitubescanbeusedinpipesofdiameterbetween50mmand250mmandwithdiameterratiosβbetween0,4and0,75inclusive.5.1.4ClassicalVenturitubewitharough-weldedsheet-ironconvergentsectionThisisaclassicalVenturitubenormallyfabricatedbywelding.Forlargersizesitmaynotbemachinedifthetolerancerequiredin5.2.4canbeachieved,butinthesmallersizesthethroatismachined.TheseclassicalVenturitubescanbeusedinpipesofdiameterbetween200mmand1200mmandwithdiameterratiosβbetween0,4and0,7inclusive.5.2Generalshape5.2.1Figure1showsasectionthroughthecentrelineofthethroatofaclassicalVenturitube.ThelettersusedinthetextrefertothoseshownonFigure1.--```,``-`-`,,`,,`,`,,`---TheclassicalVenturitubeismadeupofanentrancecylinderAconnectedtoaconicalconvergentsectionB,acylindricalthroatCandaconicaldivergentsectionE.Theinternalsurfaceofthedeviceiscylindricalandconcentricwiththepipecentreline.Thecoaxialityoftheconvergentsectionandthecylindricalthroatisassessedbyvisualinspection.5.2.2Theminimumcylinderlength,measuredfromtheplanecontainingtheintersectionoftheconefrustumBwiththecylinderA,mayvaryasaresultofthemanufacturingprocess(see5.2.8to5.2.10).Itis,however,recommendedthatitbechosentobeequaltoD.CopyrightInternationalOrganization©ISOfor2003Standardization—Allrightsreserved3ReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleISO5167-4:2003(E)TheentrancecylinderdiameterDshallbemeasuredintheplaneoftheupstreampressuretappings.Thenumberofmeasurementsshallbeatleastequaltothenumberofpressuretappings(withaminimumoffour).Thediametersshallbemeasuredneareachpairofpressuretappings,andalsobetweenthesepairs.ThearithmeticmeanvalueofthesemeasurementsshallbetakenasthevalueofDinthecalculations.Diametersshallalsobemeasuredinplanesotherthantheplaneofthepressuretappings.Nodiameteralongtheentrancecylindershalldifferbymorethan0,4%fromthevalueofthemeandiameter.Thisrequirementissatisfiedwhenthedifferenceinthelengthofanyofthemeasureddiameterscomplieswiththesaidrequirementwithrespecttothemeanofthemeasureddiameters.--```,``-`-`,,`,,`,`,,`---Key1conicalconvergentE2cylindricalthroat,C3conicalconvergentB4entrancecylinderA5connectingplanesa7°uϕu15°bFlowdirectioncSee5.4.7Figure1—GeometricprofileoftheclassicalVenturitubeCopyrightInternational4OrganizationforStandardization©ISO2003—AllrightsreservedReproducedbyIHSunderlicensewithISONoreproductionornetworkingpermittedwithoutlicensefromIHSNotforResaleISO5167-4:2003(E)5.2.3TheconvergentsectionBshallbeconicalandshallhaveanincludedangleof21°±1°foralltypesofclassicalVenturitube.ItislimitedupstreambytheplanecontainingtheintersectionoftheconefrustumBwiththeentrancetocylinderA(ortheirprolongations)anddownstreambytheplanecontainingtheintersectionoftheconefrustumBwiththethroatC(ortheirprolongations).TheoveralllengthoftheconvergentBmeasuredparalleltothecentrelineoftheVenturitubeisthereforeapproximatelyequalto2,7(D−d).TheconvergentsectionBisblendedtotheentrancecylinderAbyacurvatureofradiusR1,thevalueofwhichdependsonthetypeofclassicalVenturitube.Theprofileoftheconvergentsectionshallbecheckedbymeansofatemplate.Thedeviationbetweenthetemplateandtheconicalsectionoftheconvergentsectionshallnotexceed,inanyplace,0,004D.--```,``-`-`,,`,,`,`,,`---Theinternalsurfaceoftheconicalsectionoftheconvergentsectionistakenasbeingasurfaceofrevolutioniftwodiameterssituatedinthesameplaneperpendiculartotheaxisofrevolutiondonotdifferfromthevalueofthemeandiameterbymorethan0,4%.ItshallbecheckedinthesamewaythatthejoiningcurvaturewitharadiusR1isasurfaceofrevolution.5.2.4ThethroatCshallbecylindricalwithadiameterd.ItislimitedupstreambytheplanecontainingtheintersectionoftheconefrustumBwiththethroatC(ortheirprolongations)anddownstreambytheplanecontainingtheintersectionofthethroatCwiththeconefrustumE(ortheirprolongations).ThelengthofthethroatC,i.ethedistancebetweenthosetwoplanes,shallbeequaltod±0,03dwhateverthetypeofclassicalVenturitube.ThethroatCisconnectedtotheconvergentsectionBbyacurvatureofradiusR2andtothedivergentsec