带式输送机外文

LatestDevelopmentsinBeltConveyorTechnologyM.A.AlspaughOverlandConveyorCo.,Inc.PresentedatMINExpo2004LasVegas,NV,USASeptember27,2004AbstractBulkmaterialtransportationrequirementshavecontinuedtopressthebeltconveyorindustrytocarryhighertonnagesoverlongerdistancesandmorediverseroutes.Inorderkeepup,significanttechnologyadvanceshavebeenrequiredinthefieldofsystemdesign,analysisandnumericalsimulation.Theapplicationoftraditionalcomponentsinnon-traditionalapplicationsrequiringhorizontalcurvesandintermediatedriveshavechangedandexpandedbeltconveyorpossibilities.Examplesofcomplexconveyingapplicationsalongwiththenumericaltoolsrequiredtoinsurereliabilityandavailabilitywillbereviewed.IntroductionAlthoughthetitleofthispresentationindicates“new”developmentsinbeltconveyortechnologywillbepresented,mostoftheideasandmethodsofferedherehavebeenaroundforsometime.Wedoubtanysinglepieceofequipmentorideapresentedwillbe“new”tomanyofyou.Whatis“new”arethesignificantandcomplexsystemsbeingbuiltwithmostlymaturecomponents.Whatisalso“new”arethesystemdesigntoolsandmethodsusedtoputthesecomponentstogetherintouniqueconveyancesystemsdesignedtosolveeverexpandingbulkmaterialhandlingneeds.Andwhatisalso“new”istheincreasingabilitytoproduceaccurateEnergyEfficiencycomputersimulationsofsystemperformancepriortothefirstsystemtest(commissioning).Assuch,themainfocusofthispresentationwillbethelatestdevelopmentsincomplexsystemdesignessentialtoproperlyengineerandoptimizetoday’slongdistanceconveyancerequirements.Thefourspecifictopicscoveredwillbe:IdlerResistanceEnergyEfficiencyDistributedPowerAnalysisandSimulationEnergyEfficiencyMinimizingoverallpowerconsumptionisacriticalaspectofanyprojectandbeltconveyorsarenodifferent.Althoughbeltconveyorshavealwaysbeenanefficientmeansoftransportinglargetonnagesascomparedtoothertransportmethods,therearestillvariousmethodstoreducepowerrequirementsonoverlandconveyors.Themainresistancesofabeltconveyoraremadeupof:IdlerResistanceRubberindentationduetoidlersupportMaterial/BeltflexureduetosagbeingidlersAlignmentTheseresistancesplusmiscellaneoussecondaryresistancesandforcestoovercomegravity(lift)makeuptherequiredpowertomovethematerial.1Inatypicalin-plantconveyorof400mlength,powermightbebrokenintoitscomponentsasperFigure1withliftmakingupthelargestsinglecomponentbutallfrictionforcesmakingupthemajority.Figure1Inahighinclineconveyorsuchasanundergroundmineslopebelt,powermightbebrokendownasperFigure2,withliftcontributingahugemajority.Sincethereisnowaytoreducegravityforces,therearenomeanstosignificantlyreducepoweronhighinclinebelts.Figure2Butinalongoverlandconveyor,powercomponentswilllookmuchmorelikeFigure3,withfrictionalcomponentsmakingupalmostallthepower.Inthiscase,attentiontothemainresistancesisessential.Figure3Thespecificsofpowercalculationisbeyondthescopeofthispaperbutitisimportanttonotethatsignificantresearchhasbeendoneonallfourareasofidlers,rubberindentation,alignmentandmaterial/beltflexureoverthelastfewyears.Andalthoughnoteveryoneisinagreementastohowtohandleeachspecificarea,itisgenerallywellacceptedthatattentiontothesemainresistancesisnecessaryandimportanttooverallprojecteconomics.Atthe2004SMEannualmeeting,WalterKungofMANTakrafpresentedapapertitled“TheHendersonCoarseOreConveyingSystem-AReviewofCommissioning,Start-upandOperation”2.ThisprojectwascommissionedinDecember1999andconsistedofa24km(3flight)overlandconveyingsystemtoreplacetheundergroundminetomillrailhaulagesystem.Figure4-HendersonPC2toPC3TransferHouseThelongestconveyorinthissystem(PC2)was16.28kminlengthwith475moflift.Themostimportantsystemfactwasthat50%oftheoperatingpower(~4000kWat1783mtphand4.6m/s)wasrequiredtoturnanemptybeltthereforepowerefficiencywascritical.Verycloseattentionwasfocusedontheidlers,beltcoverrubberandalignment.OnewaytodocumentrelativedifferencesinefficiencyistousetheDIN22101standarddefinitionof“equivalentfrictionfactor-f”asawaytocomparethetotalofthemainresistances.Inthepast,atypicalDINfusedfordesignofaconveyorlikethismightbearound0.016.MANTakrafwasestimatingtheirattentiontopowerwouldallowthemtorealizeanfof0.011,areductionofover30%.Thisreductioncontributedasignificantsavingincapitalcostoftheequipment.Theactualmeasuredresultsover6operatingshiftsaftercommissioningshowedthevaluetobe0.0075,oreven30%lowerthanexpected.Mr.KungstatedthisreductionfromexpectedtoresultinanadditionalUS$100,000savingsperyearinelectricitycostsalone.RouteOptimizationFigure5-TianginChinaHorizontalAdaptabilityOfcoursethemostefficientwaytotransportmaterialfromonepointtothenextisasdirectlyaspossible.Butaswecontinuetotransportlongerdistancesbyconveyor,thepossibilityofconveyinginastraightlineislessandlesslikelyasmanynaturalandman-madeobstaclesexist.Thefirsthorizontallycurvedconveyorswereinstalledmanyyearsago,buttodayitseemsjustabouteveryoverlandconveyorbeinginstalledhasatleastonehorizontalchangeindirection.Andtoday’stechnologyallowsdesignerstoaccommodatethesecurvesrelativelyeasily.Figures5and6showsanoverlandconveyortransportingcoalfromthestockpiletotheshiploaderattheTianjinChinaPortAuthorityi