会员注册 | 登录 | 微信快捷登录 支付宝快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

   首页 人人文库网 > 资源分类 > DOC文档下载

外文翻译--采煤机.doc

  • 资源星级:
  • 资源大小:144.50KB   全文页数:9页
  • 资源格式: DOC        下载权限:注册会员
您还没有登陆,请先登录。登陆后即可下载此文档。
  合作网站登录: 微信快捷登录 支付宝快捷登录   QQ登录   微博登录
友情提示
2:本站资源不支持迅雷下载,请使用浏览器直接下载(不支持QQ浏览器)
3:本站资源下载后的文档和图纸-无水印,预览文档经过压缩,下载后原文更清晰   

外文翻译--采煤机.doc

附录1英文原文SHEARERSINTRODUCTIONLongwallminingintheUnitedStatesisfinallybeginningtocarveoutasignificantpercentageofundergroundminingtonnage.Althoughlongwallinstallationsarecontinuingthroughoutthecountry–atlastcountinelevenstatestheconcentrationisintheEasterncoalfields,withWestVirginialeadingallstates.Asaresultofincreasedexperiencewithlongwallinstallationsunderdifferentcondition,certainimprovementsarebeingmade.Forinstance,roofsupportshieldsarebeingutilizedtoagreaterextent,andruggednessisbeingstressedinallareas.Modificationsarebeingconsideredinordertousethelongwallinothertypesofseamsandseamconditions.Evidentlylongwallusersliketheresultsthattheyhavebeengettingbecausetheyhavebeeninstallingmoresystems.Sincelongwallminingisobviouslygoingtoplayamuchlargerroleinthecoalminingindustryinthefuture,thereisagreatneedforacomprehensivebookthatpresents,systematically,everymajorsubjectinlongwallmining.MorethanadecadeofmodernlongwallminingintheUnitedStateshasdemonstratedthatitisinherentlysafeandcomplieseasilywithcurrentlaws.Itisalsohighlyproductive,provideditisproperlydesignedandoperated.However,thegrowthoflongwallmining,thoughsteady,hasbeenslow.Oneofthereasonsforthisisthelackofacomprehensivetechnicalbackgroundliteraturefortrainingpurposes.Thisbookattemptstofillsuchagap.Forthefirsttime,anyonewhowouldliketolearnmoreaboutlongwallminingcanfindallofthemajortopicsinonebook.Thus,thisbookisamilestoneinthedevelopmentoflongwallmining.SHEARERSLongwallequipmentconsistsofthreemajorcomponentsthehydraulicallypoweredroofsupport,thechainconveyor,andthecoalcuttingmachine.Thetwodifferenttypesofcoalcuttingequipmentusedincoalminesareshearersandplows.Plowsareusedinlowseams,42in.orless.Theunitconsistsofsteelconstructionequippedwithcarbontippedbits.Thispassivesteelunitisengagedtoaguidingsystemonthefaceconveyor.Anendlessroundlinkchainpoweredbysynchronizedelectricdrivesoneachendofthefaceconveyorpullstheplowbodyatspeedsbetween120and420ft/minalongtheface.Forthecuttingprocesstheplowhastobeforcedagainstthecoalface.Thisisdonebyhydrauliccylinderattachedtothegobsideofthefaceconveyorandtothebaseofthesupports,orbyaseparatehydraulicprop.Forcesofbetween1and3tonsareappliedpercylinder.Aplowdriveisattachedtoeachdriveframeofthefaceconveyor.Only30to60ofthedrivepowersuppliedtotheplowisusedforcuttingandloadingofcoaltheremainderislostinfriction.Thismeansthatthepowerlossisconsiderablyhigherthanthatofashearer,whichuses75to85ofitspowerfortheremovalofthecoal.Asaresult,ratherlargedrivesarerequiredatthefaceends.Althoughtherearemanymodels,theshearerhasseveralcommonbasiccomponents.AdoubleendedrangingdrumshearerFig.8.1,forexample,consistsoffourmajorcomponentselectricmotors,gearheads,haulageunitpowerpack,andcuttingdrums.Theelectricmotorrangingfrom300to1000hp.223750kwisthepowersourcefortheshearer.Itprovidespowertorunthehydraulicpumpsinthehaulageunitandthegearheadsforthecuttingdrum.Thelargecapacityshearersaregenerallyequippedwithtwoelectricmotorsoneofthehaulageunitandonegearheadandtheotherfortheothergearheadandotherancillaryequipment.Themotorscanberemotelycontrolled.Therearetwogearheads,oneontheleftandtheotherontherighthandsideoftheshearer.Eachgearheadconsistsofagearheadgearboxandarangingarm.Thecuttingdrumislacedwithspiralvanesonwhichthecuttingbitsaremounted.Itsdiameterrangesfrom34to72in.0.861.83mwithrotationalspeedsfrom30to105rpm.Thetrendsaretowardfewerbutlargerbitsandslowerdrumspeedforbettercuttingefficiencyandlesscoaldustproduction.Thedrumsarealsoequippedwithpowercowlstoincreasethecoalloadingefficiency.Thepowercowlisusuallylocatedbehindthecuttingdrum.Forthatreason,itcanberotatedafull180°.Theelectricmotor,haulageunit,andgearheadboxescombinetoformtheshearersbodywhichismountedontheunderframe.Theunderframehasfourslidingshoes.Thefacesideshoesarefittedandrideonthefacesidetopguideofthefaceconveyorpan,andtheothertwogobsideslidingshoesarefittedonaguidetubetopreventderailment.Thereamingspeedoftheshearerrangesfrom19to46ft/min5.814.0m/min.Inaddition,theshearerisequippedwithauxiliaryhydraulicpumpsandcontrolvalvesforoperatingtherangingarmsandpowercowls,watersprayingdevices,cable,chainanchorageandtensioners,andsoon.TYPESOFMODERNSHEARERSSinceitsfirstappearancein1954,theshearerhasundergonecontinuouschangesbothincapabilityandstructure.Itisnowthemajorcuttingmachineinlongwallcoalfaces.Therearetwotypesofshearers,singleanddoubledrum.Intheearliermodels,thedruminthesingledrumshearerismountedontheshearersbodyandcannotbeadjustedforheight.Thereforeitisnotsuitableforareaswherethereareconstantchangesinseamthicknessandfloorundulation.Thus,thesingleendedfixeddrumshearerisusedmostlyforthinseams.Inordertoaccommodatethechangingofseamthicknessandfloorundulationthesingledrumshearerswitharangingarmareused.Therangingarmcanberaisedupanddownbyhydrauliccontroldevices.Butwhentheseamexceedsacertainthickness,theshearercannotcuttheentireseamheightinonecutandareturncuttingtripisnecessarytocompleteafullwebcut.Furthermore,sincethedrumislocatedontheheadentryside,itgenerallyrequiresanicheinthetailentryside.Anicheisprecutfaceend,onewebdeepandashearerslengthlong.Withanicheatthefaceendtheshearercanturnaround.Nowadays,thedoublerangingdrumshearersareusedpredominantly.Theshearercutsthewholeseamheightinonetrip.Thetwodrumscanbepositionedtoanyrequiredheightwithinthedesignedrangeduringcuttingandloweredwellbelowthefloorlevel.Thearrangementofthedrumsenablesthewholeseamtobecutineitherdirectionoftravel,therebyensuringrapidfaceadvanceandshorteningroofexposuretime.Therearevarioustypesofdoublerangingdrumshearers.Basedonthelocationofthedrums,therearetwotypesonewithonedrummountedoneachsideoftheshearersbodyandtheotherwithbothdrumsmountedononesideofthemachine.Theformertypeisthemostwidelyused.Itsadvantageisthatwithonedrumoneachsideoftheshearer,itcansumpineitherdirection.Duringthecuttingtrip,theleadingdrumcutstheupper70oftheseamheightwhilethereardrumcutsthelower30andcleansupthebrokencoalonthefloor.Thetwodrumsareapproximately2333ft.710mapart.Whenthesheareristravelingintheoppositedirectiontothatofthefaceconveyor,thecoalcutbytheleadingdrumhastopassundertheshearersbody,whichincreasesthemovingresistanceoftheshearerandthefaceconveyorandcouldcauseacrowdingcondition.Ifthebrokencoalistoolarge,itmayblocktheshearerandstoptheoperation.Ingeneral,whentheshearerandfaceconveyoraretravelingintheoppositedirections,approximately70ofthecoaltakenbytheleadingdrumwillpassundertheshearer.Butwhentheyaretravelinginthesamedirection,thecoaltakendownbythereardrumtogetherwiththefloatcoalfromthefloorconstitutetheapproximately30ofthecoalthathastopassundertheshearer.Theformercaseconsumes25morepowerthanthelatter.Ascomparedtothesingleendedshearer,theunderframeofthedoubleendedshearerishigher,therebyensuringasufficientcrosssectionforcoalpassage.Basedonthemethodofadjustingtheheightofthecuttingdrum,therearealsotwotypesofshearersrangingarmshearerandgearheadshearer.Theformeroneiscommonlyused,whereasthelatteroneisarecentdevelopment.TheadvantageofthegearheadshearerFig.8.2isthatthehaulageunitislocatedatthecenteroftheshearersbodyandmountedontheunderframe.Onbothsidesofthehaulageunit,thereisagearhead.Eachgearheadcontainsanelectricmotorandaspeedreductionunit.Thegearheadisraisedandloweredbyahydraulicram.Theadjustablerangeofcuttingheightcanreachupto4.6ft.Inselectingtheshearer,miningheightshouldfirstbeconsideredthatis,thediameterofthecuttingdrum,bodyheight,lengthoftherangingarm,andswinganglemustbeproperlyselected.Forthedoubleendedrangingdrumshearer,themaximumminingheightcannotexceedtwicethediameterofthecuttingdrum.TheminingheightcanbedeterminedbyFig.8.3HHbB/2LsinαD/28.1WhereHseamthicknessorminingheightHbshearersbodyheightBbodydepthLlengthoftherangingarmαtheanglebetweentherangingarmandthehorizontallinewhentherangingarmisraisedtoitsmaximumheight

注意事项

本文(外文翻译--采煤机.doc)为本站会员(英文资料库)主动上传,人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对上载内容本身不做任何修改或编辑。 若此文所含内容侵犯了您的版权或隐私,请立即通知人人文库网([email protected]),我们立即给予删除!

温馨提示:如果因为网速或其他原因下载失败请重新下载,重复下载不扣分。

copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5