saearp901

SAETechnicalStandardsBoardRulesprovidethat:“ThisreportispublishedbySAEtoadvancethestateoftechnicalandengineeringsciences.Theuseofthisreportisentirelyvoluntary,anditsapplicabilityandsuitabilityforanyparticularuse,includinganypatentinfringementarisingtherefrom,isthesoleresponsibilityoftheuser.”SAEreviewseachtechnicalreportatleasteveryfiveyearsatwhichtimeitmaybereaffirmed,revised,orcancelled.SAEinvitesyourwrittencommentsandsuggestions.Copyright2001SocietyofAutomotiveEngineers,Inc.Allrightsreserved.PrintedinU.S.A.TOPLACEADOCUMENTORDER:[phone]FAX:[phone]SAEWEBADDRESS::Thistestmethoddescribesaprocedureformeasuringthelargestporeorholeinafilterorsimilarfluid-permeableporousstructure.Astandardrefereetestmethodforprecisedeterminationorresolutionofdisputesisspecified.Asimplerinspectiontestprocedureforqualityassurance“go-no-go”measurementisalsogiven.Bubble-pointtestingphysics,analysisofbubble-pointtestdata,andcorrelationwithothermethodsofporesizedeterminationareseparatelydiscussedintheappendix.2.APPLICABLEDOCUMENTS:Thefollowingpublicationsformapartofthisdocumenttotheextentspecifiedherein.ThelatestissueofSAEpublicationsshallapply.Theapplicableissueofotherpublicationsshallbetheissueineffectonthedateofthepurchaseorder.Intheeventofconflictbetweenthetextofthisdocumentandreferencescitedherein,thetextofthisdocumenttakesprecedence.Nothinginthisdocument,however,supersedesapplicablelawsandregulationsunlessaspecificexemptionhasbeenobtained.2.1U.S.GovernmentPublications:AvailablefromDODSSP,SubscriptionServicesDesk,Building4D,700RobbinsAvenue,Philadelphia,PA19111-5094.MIL-H-5606HydraulicFluid,PetroleumBase;Aircraft;MissileandOrdnanceMIL-PRF-5624TurbineFuel,Aviation,GradesJP-4,JP-5,JP5/JP-8STMIL-E-51454EthylAlcohol,(Ethanol)SAEARP901RevisionA-2-3.METHODOUTLINE:Thefilterisimmersedinatestliquidwhichwetsandsaturatesthefilterporestructure.Gaspressureisappliedtoonesideoftheporouswallsothattheliquidphasewhichwetstheporesisdisplacedbythegas.Thegaspressureisslowlyincreaseduntilthefirststeadystreamofgasbubblesisobservedtoemitfromapointontheporoussurface.Themeasuredgaspressurerequiredtoformthe“firstbubble”isessentiallyequaltothepressureforcewhichisinequilibriumwiththesurfacetensionforceatthelargestpore.Thisbubble-pointpressureisarelativemeasureoftheporesizeafterappropriatecorrectionsforimmersiondepthandtestliquidsurfacetensionhavebeenmade.4.REFEREETEST:Capillarypressureor“bubble-point”testshavelongbeenusedtomeasurethelargestporeandcharacterizetheporesizedistributionofvariousporousmaterials.Manydifferentmethodsoftestingandanalysishavebeendeveloped.Nobubble-pointtestmeasuresactualporesize,butonlyallowscorrelationofthemeasuredcapillarypressurewithsomedimensionalcharacteristicoftheporestructure.Rationalizationofbubble-pointtestdatadependsondetaileddefinitionofthetestmethod,analysisandcorrelationemployed.Therefore,astandardrefereetestisnecessarytoassurecommoninterpretationofdataandunderstandingofspecifications.4.1TestEquipment:Suitablebubble-pointtestequipmentincludesasourceofcleancompressedairornitrogenwithprovisionsforregulatingandmeasuringthegaspressure.Atestliquidcontainerandappropriatefixturesforsealingandholdingthetestelementarealsorequired.Furtherprovisionsformaintainingsystemcleanlinessmaybedesirable,especiallyforCleanRoomoperations,buttheyarenotgenerallyrequiredforordinarytesting.AsuitableapparatusfortypicalfilterelementsisshownschematicallyinFigure1andrequiresthefollowingcomponentsortheirfunctionalequivalent.4.1.1Shut-offvalve(optional)toallowdisconnectingandservicingothercomponents(1).4.1.2Water-oilseparator/filterorotherprovisiontoinsurecleancompressedairornitrogengas(2).4.1.3Primarypressureregulatortoreducegaspressurebelowthemaximuminletpressureofthelowpressureregulator(3).4.1.4Secondaryprecisionlowpressureregulatorto(0to50inofwaterpressureorsimilarrange)forfinalgaspressurecontrol(4).4.1.5Three-wayPTFEplugvalve(optional)tofacilitateventingoftestelements(5).4.1.6Manometer,preferablywell-type,orcalibratedpressuregagetoreadgaspressurewithaprecisionofatleast0.1inofwaterpressure(2.54mm)(6).4.1.7Tankorsimilarcontainerforholdingtestliquidandallowingobservationofbubblesfromtestelement.SAEARP901RevisionA-3-FIGURE1-Bubble-PointTestApparatusSAEARP901RevisionA-4-4.1.8Meansformaintainingandmeasuringtestliquidtemperatureintherangeof79°F±5°F.4.2TestLiquid:ThestandardrefereetestliquidisspecifiedtobeAmericanChemicalSocietyreagentgradeisopropanol(isopropylalcohol)havingasurfacetensionof21.15dynes/cm±0.10dynes/cmat77°F(25°C).Substitutionsarenotpermitted.Othertestliquidsmaybeusedforroutine,non-refereebubble-pointtestingprovidedthattestresultsmustbeshowntocorrelatewith,standardrefereetestresults.Typicalalternativetestliquidsincludecommercialgradesofisopropanol,Ethanol3-190orotherbrandsofdenaturedethanol,andMIL-H-5606hydraulicoil,JP-5fuelandotherhydrocarbonsolventshavealsob