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【英文标准名称】:StandardPracticeforMeasuringSiftingSegregationTendenciesofBulkSolids
【原文标准名称】:测定大块固体的筛分分离趋势的标准实施规程
【标准号】:ASTMD6940-2010
【标准状态】:现行
【国别】:美国
【发布日期】:2010
【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】:
【英文主题词】:bulksolids;segregation;sifting;Segregation;Bulksolids;Horizontaltesting;Siftingsegregation
【摘要】:Siftingsegregationcancausehorizontalsegregation(forexample,center-to-periphery)withinbinsusedtoholdandtransportbulksolids.Thiscanaffectfinalproductqualityinindustrialapplications.Bymeasuringabulksolid''ssegregationtendency,onecancompareresultstootherbulksolidswithknownhistory,ordetermineifthegivenbulksolidmayhaveatendencytosegregateinagivenprocess.Sifting,whichisaprocessbywhichsmallerparticlesmovethroughamatrixoflargerones,isacommonmethodofsegregation.Fourconditionsmustexistforsiftingtooccur:ADifferenceinParticleSizebetweentheIndividualComponents8212;Thisratiocanbeaslowas1.3to1.Ingeneral,thelargertheratioofparticlesizes,thegreaterthetendencyforparticlestosegregatebysifting.ASufficientlyLargeMeanParticleSize8212;Siftingsegregationcanoccurwithameanparticlesizeinthe50x03BC;mrangeandcanbecomeadominantsegregationmechanismifthemeanparticlesizeisabove100x03BC;m.SufficientlyFreeFlowingMaterial8212;Thisallowsthesmallerparticlestosiftthroughthematrixoflargerparticles.Withcohesivematerials,thefineparticlesareboundtooneanotheranddonotenterthevoidsamongthecoarseparticles.InterparticleMotion8212;Thiscanbecausedduringformationofapile,byvibration,orbyavelocitygradientacrosstheflowingmaterial.Allfouroftheseconditionsmustexistforsiftingsegregationtooccur.Ifanyoneoftheseconditionsdoesnotexist,thematerialwillnotsegregatebythismechanism.Note18212;Thequalityoftheresultproducedbythispracticeisdependentonthecompetenceofthepersonnelperformingit,andthesuitabilityoftheequipmentandfacilitiesused.AgenciesthatmeetthecriteriaofPracticeD3740aregenerallyconsideredcapableofcompetentandobjectivetesting/sampling/inspection/etc.UsersofthispracticearecautionedthatcompliancewithPracticeD3740doesnotinitselfassurereliableresults.Reliableresultsdependonmanyfactors;PracticeD3740providesameansofevaluatingsomeofthosefactors.PracticeD3740wasdevelopedforagenciesengagedinthetestingand/orinspectionofsoilandrock.Assuchitisnottotallyapplicabletoagenciesperformingthispractice.However,usersofthispracticeshouldrecognizethattheframeworkofPracticeD3740isappropriateforevaluatingthequalityofanagencyperformingthispractice.Currentlythereisnoknownqualifyingnationalauthoritythatinspectsagenciesthatperformthispractice.1.1Thispracticecoversanapparatusandprocedureforsimulatingthesegregationtendenciesofbulksolidsbymeansofthesiftingmechanism.1.2Temperature-andhumidity-sensitivebulksolidsmayneedtobetestedatdifferenttemperaturesandmoisturecontents,aswouldhappeninanindustrialenvironment.1.3Themaximumparticlesizeshouldbelimitedto3mm,toreducethelikelihoodofbindingtheslidegate.1.4Thisstandardisnotapplicableto......
【中国标准分类号】:A42
【国际标准分类号】:19_120
【页数】:5P.;A4
【正文语种】:英语