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翻译英文原文COMMINUTIONINANON-CYLINDRICALROLLCRUSHER*P.VELLETRI~andD.M.WEEDON~~[Dept.ofMechanical&MaterialsEngineering,UniversityofWesternAustralia,35StirlingHwv,Crawley6009,[e-mail]§FacultyofEngineeringandPhysicalSystems,CentralQueenslandUniversity,POBox1!:;19,Gladstone,Qld.4680,Australia(Received3May2001;accepted4September2001)ABSTRACTLowreductionratiosandhighwearratesarethetwocharacteristicsntostcommonhassociatedwithconventionalrollcrushers.Becauseofthis,rollcrushersarenotoftenconsideredJoruseinmineralprocessingcircuits,attdmanyoftheiradvantagesarebeinglargelyoverlooked.Thispaperdescribesanovelrollcrusherthathasbeendevelopediptordertoaddresstheseissues.RelbrredtoastheNCRC(Non-CylindricalRollCrusher),thenewcrusherincorporatestworolls[e-mail]mprovetheangleqfnip,enablingtheNCRCtoachievehigherreductionratiosthanconventionalrollcrushers.Testswithamodelprototypehaveindicatedtharevellfi)rveryhardores,reductionratiosexceedinglO:lcanbeattained.Inaddition,sincethecomminutionprocessintheNCRCcombinestheactionsofrollarMjawcrushersthereisapossibiliO'thatthenewprofilesmayleadtoreducedrollwearrates.©2001ElsevierScienceLtd.Allrightsreserved.Keywords:Comminution;crushingINTRODUCTIONConventionalrollcrusherssufferfromseveraldisadvantagesthathavelcdtotheirlackofpopularityinmineralprocessingapplications.Inparticular,theirlowreductionratios(typicallylimitedtoabout3:1)andhighwearratesmakethemunattractivewhencomparedtoothertypesofcomminutionequipment,suchasconecrushers.Thereare,however,somecharacteristicsofrollcrushersthatareverydesirablefromamineralprocessingpointofview.Therelativelyconstantoperatinggapinarollcrushergivesgoodcontroloverproductsize.Theuseofspring-loadedrollsmakethesemachinestoleranttouncrushablematerial(suchastrampmetal).Inaddition,rollcrushersworkbydrawingmaterialintothecompressionregionbetweentherollsanddonotrelyongravitationalfeeci~likeconeandjawcrushers.Thisgeneratesacontinuouscrushingcycle,whichyieldshighthroughputratesandalsomakesthecrushercapableofprocessingwetandstickyore.TheNCRCisanovelrollcrusherthathasbeendcvelopedattheUniversityofWesternAustraliainordcrtoaddresssomeoftheproblemsassociatedwithconventionalrollcrushers.Thenewcrusherincorporatestworollscomprisedofanalternatingarrangementofplaneandconvexorconcavesurfaccs.Thcseuniquerollprofilesimprovetheangleofnip,enablingtheNCRCtoachievehigherreductionratiosthanconventionalrollcrushers.Preliminarytestswithamodelprototypehaveindicatedthat,evenforveryhardoics,reductionratiosexceeding10:Icanbeattained(VellelriandWeedon,2000).Theseinitialfindingswereobtainedforsingleparticlefeed.wherethereisnosignificantinteractionbetweenparticlesduringcomminution.Thecurrentworkextendstheexistingresultsbvexamininginulti-particlecomminutionintheNCRC.Italsolooksatvariousothcrfactorsthatinfluencctheperli~rmanceoftheNCRCandexplorestheeffectivenessofusingtheNCRCfortheprocessingofmillscats.PRINCIPLEOFOPERATIONTheangleofnipisoneofthemainlectorseffcctingtheperformanceofarollcrusher.Smallernipanglesarebeneficialsincetheyincreasetl~elikelihoodofparlictesbcinggrabbedandcrushedbylherolls.Foragivenfeedsizeandrollgap,thenipangleinaconventionalrtHlcrusherislimitedbythesizeofthcrolls.TheNCRCattemptstoovercomethislimitationthroughtheuseofprofiledrolls,whichimprovetheangleofnipatvariouspointsduringonecycle(orrevolution)oftherolls.Inadditiontothenipangle,anumberofotherfactorsincludingvariationmrollgapandmodeofcommmutionwereconsideredwhenselectingIllerollprofiles.ThefinalshapesoftheNCRCrollsareshowninFigureI.Oneoftherollsconsists{sIanalternatingarrangementofplaneandconvexsurfaces,whiletheotherisformedfromanalternatingarrangementofphmeandconcavesurlaccs.TheshapeoftherollsontheNCRCresultinseveraluniquecharacteristics.Tilemostimportantisthat,lk)ragivenparticlesizeandrollgap,thenipanglegeneratedmtheNCRCwillnotremainconstantastherollsrotate.Therewillbetimeswhenthenipangleismuchlowerthanitwouldbeforthesamesizedcylindricalrollsandtimeswhenitwillbemuchhighcr.Theactualvariationinnipangleovera60degreerollrotationisillustratedinFigure2,whichalsoshowsthenipanglegeneratedundersimilarconditionsmacylindricalrollcrusherofcomparablesize.Thesenipangleswerecalculatedfora25ramdiametercircularparticlebetweenrollofapproximately200ramdiametersetataImmminimumgap.Thisexamplecanbeusedtoillustratethepotentialadvantageofusingnon-cylindricalrolls.Inorderforaparticletobegripped,thcangleofnipshouldnormallynotexceed25°.Thus,thecylindricalrollcrusherwouldnevernipthisparticle,sincetheactualnipangleremainsconstantatapproximately52°.ThenipanglegeneratedbytheNCRC,however,tidlsbelow25°onceastherollsrotateby(~0degrees.Thismeansthatthenon-cylindricalrollshaveapossibilityofnippingtheparticlc6timesduringonerollrewHution.EXPERIMENTALPROCEDUREThelaboratoryscaleprototypeoftheNCRC(Figure3)consistsoftworollunits,eachcomprisingamotor,gearboxandprofiledroll.Bothunitsaremountedonlinearbearings,whicheffectivelysupportanyverticalcomponcnto