翻譯原文MotorizedPulleysSolveHarshEnvironmentalProblemsatNorthAmericanShipLoadingTerminalsKeywords:MotorizedPulleys,ShipLoaders,BucketWheelStackerReclaimers,ConveyorBelts1AbstractThispaperpresentsdesignandoperationalchallengesfacedbythreedifferentshiploadingfacilityoperators,onehandlingexportcoalontheGulfofAlaskaandtwohandlingtaconiteironorepelletsontheNorthAmericanGreatLakes.Extremetemperaturesandabrasivematerials,coupledwithaneedforcompactness,madeinternally-poweredandhermetically-sealedMotorizedPulleystheoptimaldesignchoicefordrivingshiploaderandbucketwheelreclaimerconveyorbelts.OriginallyaEuropeanidea,theMotorizedPulleywasslowingainingacceptanceinNorthAmericainthetwentiethcentury.However,theinternally-poweredconveyorbeltdrivehasrecentlybecomemorepopular,especiallywhereambientconditions,materialhandled,orcompactequipmentdesignmakeexposeddrivesdifficulttointegrateandoperate.2IntroductionWhatdoSeward,Alaska；Superior,Wisconsin；andEscanaba,Michiganhaveincommon?Eachisthelocationofamajorrail-to-shipbulkstorageandtransferfacility,ownedandoperatedbyarailroadcompany.Eachislocatedonwaternorthof45Nlatitude,wherewintertemperaturescandropto40F(-40C)andhumidityreachnearly100%.Andeachhandlesabrasiveand/orcorrosivematerial.Oneotherimportantfeatureiscommontothesefacilities.theRulmecaMotorizedPulley.Rulmecasinternally-poweredandhermetically-sealedMotorizedPulleywasselectedtoupgradekeydrivesonshiploaderandbucketwheelreclaimerconveyorbelts.Thispaperwillrevieweachfacilityslayout,throughput,andparticularchallengesanditwillexplainwhydesignersselectedMotorizedPulleytechnology.ThesesuccessfulapplicationswillhelpexplainthegrowthinacceptanceofMotorizedPulleytechnologyinNorthAmerica,especiallyinharshenvironments.3MotorizedPulleyTechnologyTheMotorizedPulleyconceptwasdevelopedinthe1950stoprovideareliablemeansofdrivingbeltconveyors.Equipmentdesignersquicklydiscoveredthatenclosingthedrivesmotorandgearboxwithinahermetically-sealedandoil-filledpulleyshellnotonlymadethedrivecompact,italsogreatlyimprovedthedrivesreliabilityandservicelife.Fig.1:RulmecaMotorizedPulleyenclosesmotorandgearboxwithinhermetically-sealedoil-filledshelltoprotectmovingcomponentsfromharshenvironmentwhilesavingspace.Compactness,reliability,longservicelife,andlimitedmaintenancerequirementsmadetheMotorizedPulleyapopularconveyordriveforbulkhandlingequipmentdesignersinEurope.Largemachinerysuchasbucketwheelreclaimers,shiploaders,andtunnelboringequipmentsoonhadMotorizedPulleysinstalledasoriginalequipment.AndplantoperatorsbeganreplacingwornexposedconveyordriveswithMotorizedPulleysatfacilitieshandlingmaterialssuchasfertilizer,sand&gravel,steel,ore,andwoodproducts.EachMotorizedPulleyconsistsofanACsquirrel-cageinductionmotor,directlycoupledtoahelical/spurgearbox,mountedonafixed(non-rotating)shaft,andhermeticallysealedwithinthecylindricalpulleyshell.TodaysMotorizedPulleyincorporatesawidearrayofpowersandspeedsaswellasoptionalfeatures,suchasbuilt-inmechanicalbackstops,anti-condensationheaters,andelectro-mechanicalbrakes.4AllouezDock#54.1SynopsisofUpgradeBurlingtonNorthernSantaFeRailroad(BNSF)recentlycompletedtheoverhauloftwoofthree40yearoldcrawler-mountedbucketwheelreclaimersatthecompanysrail-toshiptransferterminalfortaconitepelletslocatednearSuperior,Wisconsin.4.2ObjectiveofUpgradeTheobjectiveoftheupgradewastoreducehighmaintenanceexpensewhileimprovingsystemreliabilityinthestockpilearea.Theupgradeincludedstructuralchanges,replacementofon-boarddieselengines,andtheinstallationofRulmecaMotorizedPulleys.ThechallengeforBNSFoperationswastokeepthe40yearoldmachinesworkingefficientlyinspiteofthefactthatthemachinesmanufacturerhadgoneoutofbusinessmorethan20yearsago.TheoriginalconveyordriveswereauniquecombinationofcomponentsincludingACmotors,planetarygearboxesandpulleysmountedbetweenthecarryingandreturnstrandsofbelt.Sinceoriginalequipmentmanufacturerspartswerenolongeravailableandsincetheconveyordriveswerenon-standard,BNSFwasforcedtocustom-buildparts,anexpensiveandtime-consumingprocess.EngineeringDesignServicesrecommendedRulmecaMotorizedPulleysbecause:(1)theyarecompactandwouldfitwithinthereclaimersstructure,(2)RulmecaMotorizedPulleysandreplacementpartsarereadilyavailable,and(3)Rulmecahasalongsuccessfultrackrecordofsupplyingconveyordrivesforbucketwheelreclaimers.4.3OperatingDataAssummarizedinTable2,AllouezDock#5consistsofan87acre(0,3km2)facilityproviding5.5milliontonsofstoragecapacityinastockpilearea3.5miles(5,6km)fromthedockand72,000tonsofstorageinthedocksilos.Aconveyorsystem,5.7miles(9,2km)inlength,linksthe2railcarunloaders,the3stackerreclaimers,andtheshiploader.TaconitepelletsusuallyarriveinBNSFtrainsof150carseach35feet(10,7m)long“H-1”typeat1,800ft3(513m)capacityandareloadedintospeciallakevessels.Upto185cartrainscanhaul20,000tonsoftaconitepellets,atagrosstrainweightof27,000tons.Wintertemperaturescanreach30F(-34C).Typically,icedoesnotcoverallofLakeSuperior,butnear-completesheetsofice,fromafewinchestoseveralfeetthick,doformintheharborareaofSuperiorandSt.LouisBays.Asearlyasmid-NovemberandpersistingaslateasearlyMay,iceintheSootLocksortheharborendstheshippingseason.FrozenblocksofpelletscanbefoundinthestockpilesaslateasAugustandSeptember.The75BNSFemployeesatAllouezDock#5unloaded537trainsor79,201carsin2003.4.4MotorizedPulleyExperienceEngineeringDesignServicesandRulmecaengineersfirstpresentedtheMotorizedPulleyupgradeconceptforthebucketwheelreclaimerstoBNSFpersonnelin1995,suggestinga“DualDrive”arrangementforthetailconveyorduetoitsrequirementof200HP(150kW).AllouezDockhadbeenmaintainingthebucketwheelmachineswithouttheassistanceoftheoriginalequipmentmanufacturerformorethan10yearsin1995.However,thedualdriveconceptwasrelativelynewatthattimeandeightyearswouldelapsebeforethefirstbucketwheelreclaimerwasupgraded.By2003originalgearboxrebuildshadgottenveryexpensive.ThatyearthreeModel800HMotorizedPulleys,with31.5inch(800mm)diameterand57inch(1400mm)facewidthwerepurchased.BNSFoperationspersonnelinstalledthemin2004.EachMotorizedPulleyprovided120HP(90kW)atabeltspeedof768fpm(4m/s)onapowersupplyof460V/3ph/60Hz,generatedbythenewly-installedon-boarddieselgenerator.Thecompactdesignminimizedstructuralmodificationsandgreatlysimplifiedthe“NestedDualDrive”configurationbeneaththetailconveyor.Thesuc