带式输送机及其牵引系统机械外文文献翻译中英文翻译外文翻译.docx

带式输送机及其牵引系统机械外文文献翻译中英文翻译外文翻译.docx

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带式输送机及其牵引系统机械外文文献翻译中英文翻译外文翻译

JINGGANGSHANUNIVERSITY

外文翻译

题目调整送料量输送装置设计

学院机电工程学院

专业机械制造及其自动化

班级机制11本

（1）班

学号110611014

姓名蓝善龙

指导教师康志成教授

起讫时间2014.12.1—2015.4

教务处印制

Abstract

Bulk material transportation requirements have continued to press the belt conveyor industry to carry higher tonnages over longer distances and more diverse routes. In order keep up, significant technology advances have been required in the field of system design, analysis and numerical simulation. The application of traditional components in non-traditional applications requiring horizontal curves and intermediate drives have changed and expanded belt conveyor possibilities. Examples of complex conveying applications along with the numerical tools required to insure reliability and availability will be reviewed.

BeltConveyingSystemsDevelopmentofdrivingsystem

Amongthemethodsofmaterialconveyingemploved,beltconveyorsplayaveryimporientpartinthereliablecarryingofmaterialoverlongdistancesatcompetitivecost.Conveyorsystemshavebecomelargerandmorecomplexanddrivesystemshavealsobeengoingthroughaprocessofevolutionandwillcontinuetodoso.Nowadays,biggerbeltsrequiremorepowerandhavebroughttheneedforlargerindividualdrivesaswellasmultipledrivessuchas3drivesof750kWforonebelt（thisisthecasefortheconveyordrivesinChengzhuangMine）.Theabilitytocontroldriveaccelerationtorqueiscriticaltobeltconveyors'performance.Aefficientdrivesystemshouldbeabletoprovidesmooth,softstartswhilemaintainingbelttensionswithinthespecifiedsafelimits.Forloadsharingonmultipledrives.torqueandspeedcontrolarealsoconsiderationsinthedrivesystem'sdesign.Duetotheadvancesinconveyordrivecontroltechnology,atpresentmanymorereliable.Cost-effectiveandperformance-drivenconveyordrivesystemscoveringawiderangeofpowerareavailableforcustomers'choices[1].1Analysisonconveyordrivetechnologies1.1DirectdrivesFull-voltagestarters.

Withafull-voltagestarterdesign,theconveyorheadshaftisdirect-coupledtothemotorthroughthegeardrive.Direct8full-voltagestartersareadequateforrelativelylow-power,simple-Profileconveyors.Withdirectfull-voltagestarters.nocontrolisprovidedforvariousconveyorloadsand.dependingontheratiobetweenfull-andno-loadpowerrequirements,emptystartingtimescanbethreeorourtimesfasterthanfullload.Themaintenance-freestartingsystemissimple,low-costandveryreliable.However,theycannotcontrolstartingtorqueandmaximumstalltorque;therefore.theyarelimitedtothelow-power,simple-profileconveyorbeltdrives.

Reduced-voltagestarters.Asconveyorpowerrequirementsincrease,controllingtheappliedmotortorqueduringtheaccelerationperiodbecomesincreasinglyimportant.Becausemotortorqueisafunctionofvoltage,motorvoltagemustbecontrolled.Thiscanbeachievedthroughreduced-voltagestartersbyemployingasiliconcontrolledrectifier（SCR）.AcommonstartingmethodwithSCRreduced-voltagestartersistoapplylowvoltageinitiallytotakeupconveyorbeltslack.andthentoapplyatimedlinearrampuptofullvoltageandbeltspeed.However,thisstartingmethodwillnotproduceconstantconveyorbeltacceleration.Whenaccelerationiscomplete.theSCRs,whichcontroltheappliedvoltagetotheelectricmotor.arelockedinfullconduction,providingfull-linevoltagetothemotor.Motorswithhighertorqueandpull-vptorque,canprovidebetterstartingtorquewhencombinedwiththeSCRstarters,whichareavailableinsizesupto750KW.

Woundrotorinductionmotors.Woundrotorinductionmotorsare9connecteddirectlytothedrivesystemreducerandareamodifiedonfigurationofastandardACinductionmotor.Byinsertingresistanceinserieswiththemotor'srotorwindings.themodifiedmotorcontrolSystemcontrolsmotortorque.Forconveyorstarting,resistanceisplacedinserieswiththerotorforlowinitialtorque.Astheconveyoraccelerates,theresistanceisreducedslowlytomaintainaconstantaccelerationtorque.Onmultiple-drivesystems.anexternalslipresistormaybeleftinserieswiththerotorwindingstoaidinloadsharing.themotorsystemshavearelativelysimpleadesign.However,thecontrolsystemsforthesecanbehighlycomplex,becausetheyarebasedoncomputercontroloftheresistanceswitching.Today,themajorityofcontrolsystemsarecustomdesignedtomeetaconveyorsystem'sparticularspecifications.Woundrotormotorsareappropriateforsystemsrequiringmorethan400KW.

DCmotor.DCmotors.availablefromafractionofthousandsofKW，aredesignedtodeliverconstanttorquebelowbasespeedandconstantKWabovebasespeedtothemaximumallowablerevolutionsperminute（r/min）.withthemajorityofconveyordrives,a.DCshuntwoundmotorisused.Whereinthemotor'srotatingarmatureisconnectedexternally.ThemostcommontechnologyforcontrollingDCdrivesisaSCRdevice.whichallowsforcontinualvariable-speedoperation.TheDCdrivesystemismechanicallysimple,butcanincludecomplexcustom-designedelectronicstomonitorandcontrolthecompletesystem.thissystemoptionisexpensiveincomparisontoothersoft-startsystems.butitisareliable,cost-effectivedriveinapplicationsinwhichtorque,loadsharingandvariablespeedareprimaryconsiderations.DCmotorsgenerallyareusedwithhigher-powerconveyors,10includingcomplexprofileconveyorswithmultiple-drivesystems,boostertrippersystemsneedingbelttensioncontrolandconveyorsrequiringawidevariable-speedrange.

1.2Hydrokineticcoupling

2.Hydrokineticcouplings,commonlyreferredtoasfluidcouplings.arecomposedofthreebasicelements;thedrivenimpeller,whichactsasacentrifugalpump;thedrivinghydraulicturbineknownastherunnerandacasingthatenclosesthetwopowercomponents.Hydraulicfluidispumpedfromthedrivenimpellertothedrivingrunner,producingtorqueatthedrivenshaft.Becausecirculatinghydraulicfluidproducesthetorqueandspeed,nomechanicalconnectionisrequiredbetweenthedrivinganddrivershafts.Thepowerproducedbythiscouplingisbasedonthecirculatedfluid'samountanddensityandthetorqueinproportiontoinputspeed.Becausethepumpingactionwithinthefluidcouplingdependsoncentrifugalforces.theoutputspeedislessthantheinputspeed.Referredtoasslip.thisnormallyisbetween1%and3%.BasichydrokineticcouplingsareavailableinconfigurationsfromfractionaltoseveralthousandKW.

Fixed-fillfluidcouplings.Fixed-fillfluidcouplingsarethemostcommonlyusedsoft-startdevicesforconveyorswithsimplerbeltprofilesandlimitedconvex/concavesections.Theyarerelativelysimple,low-cost,reliable,maintenancefreedevicesthatprovideexcellentsoftstartingresultstothemajorityofbeltconveyorsinusetoday.

Variable-filldraincouplings.Drainable-fluidcouplingsworkonthesameprincipleasfixed-fillcouplings.Thecoupling's11impellersaremountedontheACmotorandtherunnersonthedrivenreducerhigh-speedshaft.Housingmountedtothedrivebaseenclosestheworkingcircuit.Thecoupling'srotatingcasingcontainsbleed-offorificesthatcontinuallyallowfluidtoexittheworkingcircuitintoaseparatehydraulicreservoir.Oilfromthereservoirispumpedthroughaheatexchangertoasolenoid-operatedhydraulicvalvethatcontrolsthefillingofthefluidcoupling.Tocontrolthestartingtorqueofasingle-driveconveyorsystem,theACmotorcurrentmustbemonitoredtoprovidefeedbacktothesolenoidcontrolvalve.Variablefilldraincouplingsareusedinmediumtohigh-kwconveyorsystemsandareavailableinsizesuptothousandsofkw.Thedrivescanbemechanicallycomplexanddependingonthecontrolparameters.thesystemcanbeelectronicallyintricate.Thedrivesystemcostismediumtohigh,dependinguponsizespecified.

Hydrokineticscoopcontroldrive.Thescoopcontrolfluidcouplingconsistsofthethreestandardfluidcouplingcmponents:

adrivenimpeller,adrivingrunnerandacasingthatenclosestheworkingcircuit.Thecasingisfittedwithfixedorificesthatbleedapredeterminedamountoffluidintoareservoir.Whenthescooptubeisfullyextendedintothereservoir,thecouplingis100percentfilled.Thescooptube,extendingoutsidethefluidcoupling,ispositionedusinganelectricactuatortoengagethetubefromthefullyretractedtothefullyengagedposition.Thiscontrolprovidesreasonablysmoothaccelerationrates.tobutthecomputer-basedcontrolsystemisverycomplex.ScoopcontrolcouplingsareVariable-frequencycontrol（VFC）Variablefrequencycontrolisalsooneofthedirectdrivemethods.theemphasizingdiscussionaboutithereisbecausethatithassouniquecharacteristicandsogoodperformancecomparedwithotherdrivingmethodsforbeltconveyor.VFCdevicesProvidevariablefrequencyandvoltagetotheinductionmotor,resultinginanexcellentstartingtorqueandaccelerationrateforbeltconveyordrives.VFCdrives.availablefromfractionaltoseveralthousand（kW），areelectroniccontrollersthatrectifyAClinepowertoDCand,throughaninverter,convertDCbacktoACwithfrequencyandvoltagecontrol.VFCdrivesadoptvectorcontrolordirecttorquecontrol（DTC）technology,andcanadoptdifferentoperatingspeedsaccordingtodifferentloads.VFCdrivescanmakestartingorstallingaccordingtoanygivenS-curvesrealizingtheautomatictrackforstartingorstallingcurves.VFCdrivesprovideexcellentspeedandtorquecontrolforstartingconveyorbelts.andcanalsobedesignedtoprovideloadsharingformultipledrives.easilyVFCcontrollersarefrequentlyinst