作者:标准资料网 时间:2024-05-20 19:42:24   浏览:8064   来源:标准资料网

【英文标准名称】:StandardPracticeforMeasuringFluidizationSegregationTendenciesofPowders
【原文标准名称】:测量粉末的液体化分离趋势的标准实施规程
【标准号】:ASTMD6941-2005e1
【标准状态】:现行
【国别】:
【发布日期】:2005
【实施或试行日期】:
【发布单位】:美国材料与试验协会(US-ASTM)
【起草单位】:D18.24
【标准类型】:(Practice)
【标准水平】:()
【中文主题词】:分层;流态化;测量;粉末
【英文主题词】:fluidization;powder;segregation
【摘要】:Fluidizationsegregationcancauseverticalsegregationwithinbinsusedtoholdandtransportpowders.Thiscanaffectfinalproductqualityinindustrialapplications.Bymeasuringapowderrsquo;segregationtendency,onecancompareresultstootherpowderswithknownhistory,ordetermineifthegivenpowdermayhaveatendencytosegregateinagivenprocess.Finepowdersgenerallyhavealowerpermeabilitythancoarsebulksolidsandthereforetendtoretainairlonger.Thus,whenabinisbeingfilledwithafluidizablepowder,thecoarserparticlessettleoraredrivenintothebedwhilethefinerparticlesremainfluidizednearthesurface.Fluidization,whichservesasadrivingforceforthismechanismofsegregation,islikelytooccurwhenfinepowdersarepneumaticallyconveyedintoabin,thebinisfilledordischargedathighrates,orifsufficientairflowcountertotheflowofpowderispresentwithinthebin.Note18212;Thequalityoftheresultproducedbythispracticeisdependentonthecompetenceofthepersonnelperformingit,andthesuitabilityoftheequipmentandfacilitiesused.AgenciesthatmeetthecriteriaofPracticeD3740aregenerallyconsideredcapableofcompetentandobjectivetesting/sampling/inspection/etc.UsersofthispracticearecautionedthatcompliancewithPracticeD3740doesnotinitselfassurereliableresults.Reliableresultsdependonmanyfactors;PracticeD3740providesameansofevaluatingsomeofthosefactors.PracticeD3740wasdevelopedforagenciesengagedinthetestingand/orinspectionofsoilandrock.Assuchitisnottotallyapplicabletoagenciesperformingthispractice.However,usersofthispracticeshouldrecognizethattheframeworkofPracticeD3740isappropriateforevaluatingthequalityofanagencyperformingthispractice.Currentlythereisnoknownqualifyingnationalauthoritythatinspectsagenciesthatperformthispractice.1.1Thispracticecoversanapparatusandprocedureforsimulatingthesegregationtendenciesofpowdersbymeansofthefluidizationmechanism.1.2Powdersmustbecapableofbeingfluidizedinordertobetestedbythispractice.1.3Temperature-andhumidity-sensitivepowdersmayneedtobetestedatdifferenttemperaturesandmoisturecontents,aswouldhappeninanindustrialenvironment.Further,thegassupply(type,temperature,andhumidity)shouldalsomatchtheindustrialconditions.1.4Thisstandardisnotapplicabletoallbulksolidsandsegregationmechanisms:whilefluidizationisacommonsegregationmechanismexperiencedbymanyfinepowders,othersegregationmechanismsnotevaluatedbythisstandardmightinducesegregationinpractice.1.5Theextenttowhichsegregationwilloccurinanindustrialsituationisnotonlyafunctionofthepowderanditstendencytosegregate,butalsothehandlingequipment(forexample,bindesign),process(forexample,transferrates),andenvironment.1.6Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappropriatesafetyandhealthpracticesanddeterminetheapplicabilityofregulatorylimitationspriortouse.
【中国标准分类号】:A42
【国际标准分类号】:19_120
【页数】:4P.;A4
【正文语种】: