翻譯部分英文原文：TheintroductionofConveyorBeltAconveyorbeltmaybedefinedas“anumberofloadcarryingmembersbondedtogetherwithpolymericcompounds(makingupthecarcase)；andprotectedfrommechanicaldamagebyelastomeric.Theloadcarryingmembersusuallyconsistofeitheranumberofplyofwovenfabric,asinglesolidwovenfabriccarcase,orasinglelayerofparallel,equidistantsteelcables.”Attheonset,itmustbestatedthatconveyorbeltingofanyconstruction,maybeclassifiedasFireResistantorNon-fireResistant.Incertainundergroundsituation,theformermayberequiredbylegislationorbyacceptedcodesofPractice.Forexample,intheU.K,coalminingindustry,onlyapprovedfireresistingbeltingmaybeusedunderground,mostotherdevelopedcountrieshavesimilarrequirements.Inadditiontherearemanysituationswheretheuseoffiveresistantbeltingisrecommended,forexample,incomplexmineralbeneficationplant.Itismostimportantthatintheearlystagesofdesignofanyconveyorsystems,thetypeofbeltbedetermined,addifferingcharacteristicsofthetwotypesmayinfluencethedesignofotherassociatedequipmentandproblemsmaybeintroducedifachangeisrequiredatsomelatedate.Theusetowhichanyparticularbeltistobesubjectedshouldberecordedinthepurchasespecification；sincethevariouspropertiesofabeltmayneedmodificationtoaccommodatethesometimesconflictingdemandsofcoefficientoffriction,ageingcharacteristics,moistureabsorption,etc.Alsoasagenerally,abeltofrubberconstructionhasagreaterabilitytoabsorbimpactthanoneoffireresistantconstruction.Therearethreemainconstructionalformsofbelting:(a)plyconstruction,(b)solidwovenconstruction(c)steelcordconstructionIntheaboveconstructions,(a)and(b),onlythecar-caseprovidesthestrengthtocarrytheloadandwithstandthevariousoperationalstressesthataredevelopedinthebelt.Sincethecar-caseisthemostexpensiveelementinthebelt,itisimportantthatthespecificationincorporatesadequatemeansofprotectingthismostimportantelement.In(c),theloadcarryingsteelcordsrequireslikeprotection.Additionally,thereisthespecializeddesignofbeltusedwiththeCableBeltSystemwhichwillbeseparatelydescribedwhenthatarrangementisconsidered.（1）PlyBeltConstructionWhendiscussingplybelting,thetermswarpandweftoftenoccur,forthepurposeofthissub-sectionitmaybetakenthat:warpreferstothelongitudinalstrengthofthebelt.Thelateralflexibilityofthebeltisalwaysofimportanceinorderthatitmayconformtotheidlercurve,thisbeingparticularlysowhendeeptroughidlersaretobeused.Thetraditionalbeltcarcaseconsistedofwovennaturalfabric,thisnowconsistofoneormorepliesofsyntheticfiberssuchasnylonorterylene,thewholebeingvulcanizedorfusedtogetherwiththeappropriatecovermaterial.Suchsyntheticfibersarestrongerthannaturalfibers.arethinner,moreflexibleallowingdeeperthroughintheidlers,allowtheuseofsmallerdiameterpulleysandhaveashorterelongationunderhighworkingtensions.Thecovermayberubberinthecaseofnon-fireresistingbeltsandPVC.Neoprene,etc,inthecaseoffireresistingtypes.Theminimumcoveronbothsidesofanybeltshouldbenotlessthan0.8mm,butforthetransportofalmostallmineralsmustbeincreasedhavingregardtothematerialhandled.Forexample,withmoderatelyabrasivematerialssuchascoal.rubble,ashes,etc.theminimumcarryingsidecovershouldbe2.4mmwith0.8mmonthepulleysidecovershouldbe3.2mmwith1.6mmonthepulleyside.Althoughnationalstandardsmayvary,abelttypemaybeclassifiedhavingregardtoitsstrength,anexamplebeinggiveninthenextsub-section.（2）SolidwovenbeltMuchofthatsaidaboutplybeltingappliestothesolidwovenform,butinthelater,thefibersfromwhichthebeltcar-caseisconstructedareinter-woven,thenimpregnatedtogiveasolidform,andtowhichappropriatecoversareapplied.Thefibersmaybeofhightenacitynylonwarpcottonpileandblendedweft,withcertainqualitiesofbeltingemployingapolyesterwarp.InthestandardfireresistingformthecovermaybePVC,butthishascertainlimitations,particularlyinrespectofconveyingupinclines.Toovercomethisproblemthecovermaybepolymer,whichofferstheadvantagesofnaturalrubber.Suchnitrilerubbercoversareappliedtoboththecarryingandthedrivingfacesofthebeltwithconsequentlyimprovedfrictionalcharacteristicswhichminimizeloadslierandaffordincreaseddrivingtraction.AfurtheradvantageisthatsuchcoversdonotpolishinservicesasdoesPVC.plyseparationandgivesexcellentresistancetoagewear,further,itsrotproofandresistanttomineraloils.Amodernloomtomanufacturesolidwovenbeltingemploysarapierweftincertainsystemratherthanashuttletoeliminatethedowntimerequiredtochangeweftbobbins,andalsotogivegoodselvedgefinish.ThewearingprocesswhichentailsimpregnationwithliquidPVCcompound,givinganadditional,appropriatewearresistantsurfacecoating,finallybeingpresscuredundertension.InadditiontosatisfyingU.Krequirementssuchbeltsconformtothefollowingfireresistantspecificationsandarereadilyavailableintensilestrengthsfrom315to2625kN/mofbeltwith:AustraliaMDAseries250InternationalISOR340Canada4thdraftNO.M422mFranceNF-M81-65USAUSBMSchedule2GSouthAfricaSABS971GermanyDIN2203/4Aparticularproductrangeincludesbeltsrangingintensilewarp(longitudinal)strengthrangingfrom315to1000kN/m,withassociatedwarp(lateral)strengthfrom158to350kN/m,thewefttowarpratiovariesprogressivelyfrom50downto35%.Higherstrengthbeltsthenincreasetoatensilestrengthto2625kN/m,theweftstrengthremainingconstantat350kN/m.Consequently,theweft/warpratiodropsrapidlydownto11.4%,thisbeingnecessarytoallowreadytrackinginthetroughidlers（3）SteelcordBeltconstructionTheeverincreasingdemandforstrongerbeltreinforcements,whichathigherlevelcannotbesatisfiedbytheuseofeventhehighestman-madefibers,resultingintheuseofthesteelcordbeltinwhichthewarpstrengthisprovidedbysteelcablessuchbeltismanufacturedinatwopartprocess,(a)themaxiofpolychloroprenetoproduceaentermatrixandcoversinarollingprocesswiththecordsundertension,followedbyacuringprocess.Ithasbeenfoundthatacombinationofhand(80degrees)fireresistant,antistatic(FRAS)elastomersandcordsdisplacedverticallyatadistancegreaterthan1mmleadstothefailureoftheelastomerbycompressionandtension,likeproblemsmayoccurifthereredefectsinthedesignconcept.Suchproblemsmaybeovercomebytheuseofelastomerswithahardnessinthe60to68degreerange,thisbeingastringentrequirementwhenadditivestoensurefirebycloseattentiontodriveandreturndrumdiametersandbytheuseoftonguelimitationdevicesintheconveyordrive.IntheUSA,thedetailsofthebeltemployedattheSelbyminingcomplexare:Conveyorlength:14.93kmBeltthickness:28.3mmBeltwidth:1300mmBeltstrength:6950kN/mNumberofcords:57Verticallift:990Corddiameter:13.1mmMotorpower:1010kWTheconveyorbeltisthemostimportantpartinthebeltconveyor.Inadditiontotheconveyorbelt,thereareidlers,pulleys,driveandstructure,towhichareaddedotherimportantitems,theyaremakeupthebeltconveyor.Initssimplestformabeltconveyorconsistsofapairofdrums,oneofwhichispowered,andbetweenwhichisstretchedandendlesshand.Thiselementaryarrangementhaslimiteduseforotherthanshortdistanceapplicationsuchasthecarryingofpackages,etc.Forotherthanshortdistancesthetophandmustbesupportedbyregularlyspacedidlestopreventsaggingidlersareidealforthispurpose,asetofwhichisnormallyconsistsofthreeseparaterollers,thetwoouterandshorterbeinginclinedupwardstotroughthebelt.Forlowcapacity,narrowbelts,twoidlesmaybeusedandforhighcapacityduty,fiveormoremaybeemployed.Thebottomorreturnbeltrequiresalowerlevelofsupportandgenerallymayruninaflatplaneausualarrangementbeingtousesinglerollers,atdoublethespacingdistanceusedwiththetopstrand.Withexceptionallylongconveyors,tworoblsemi-troughedreturnrollersmaybejustified.Thedrivearrangementnormallyconsistsofanelectricmotorandspeedreductiongearbox,connectedtoeachotherbysuitablecoupling.Ideally,theadoptforthetransportofanymineralshould:(a)providecontinuityofmineralclearanceformthepointofproductionwithmaximumsafetyandreliability,toensurethatproductionisnotinterruptedbytransportrestrictions.(b)becapableofhandlingthepeakoutputs.