1、英文原文Self-advancinghydraulicpoweredsupportModernlongwallminingemployshydraulicpoweredsupportsatthefacearea/Thesupportsnotonlyholdsuptheroof/pushesthefacechainconveyor/andadvancesitself/butalsoprovidesasafeenvironmentforallassociatedminingactivities/Thereforeitssuccessfulselectionandapplicationarethep
2、rerequisiteforsuccessfullongwallmining/Furthermore/duetothelargenumberofunitsrequired/thecapitalinvestedforthepowersupportusuallyaccountsformorethanhalfoftheinitialcapitalforalongwallface/Thereforebothfromtechnicalandeconomicpointsofview/thepoweredsupportisaveryimportantpieceofequipmentinalongwallfa
3、ce/Theapplicationofmodernpoweredsupportscanbetracedbacktoearly1950s/Sincethen/followingitsadoptionineverypartoftheworld/therehavebeencountlessmodelsdesignandmanufacturedinvariouscountries/Butunfortunately/therestillisnouniformsystemofclassification/Asimplifiedclassificationisusedinthissection/Sincea
4、poweredsupportconsistsoffourmajorcomponents(i/e//canopy/cavingshield/hydrauliclegsandprops/andbaseplate)/thewaysbywhichtheyareinterrelatedareusedforclassification/Inthisrespect/twofactorsaremostimportant/(1)presenceorabsenceofcavingshield-ifacavingshieldisincluded/thesupportisa“shield”type/otherwise
5、/aframeorachock；(2)numberandtypeofarrangingthehydrauliclegs-sincesupportcapacityisgenerallyproportionaltonumberofhydrauliclegs/itisimportanttospecifythenumberofhydrauliclegsthatasupporthas/Furthermore/thewaythehydrauliclegsareinstalledisimportant；forexample/averticalinstallationbetweenthebaseandthec
6、anopyhasthecavingshieldhastheleastefficiencyinsupportingtheroof/Basedonthisconcept/therearefourtypesofpoweredsupport/thatis/theframe/chock/shieldandchockshield/inorderofevolutionoftheirdevelopment/However/itmustbenotedthatthetrendofdevelopmentineachtypeissuchthatitbecomeslessdistinguishableintermsof
7、application/Thefourtypesofroofsupportscanbeobtainedforeitherlongwallretreatingoradvancingsystems/andtheyareavailableinstandard/one-web-back/andimmediateforwardsupport(IFS)versions/Withthestandardsystem/thewiningmachinetakesacutoraslice/andthearmoredfaceconveyorispushedoverbythehydraulicramsthatarefi
8、xedtothesupportunits/Thesupportunitsthenareadvancedsequentiallytotheconveyor/Withtheone-web-backsystem/asupportissetbackfromtheconveyorbyadevicethatautomaticallykeepstheleadingedgeofthesupportatafixdistancefromtheconveyor/Thisallowseasyaccessthoughthefaceandemploysthestandardmethodofadvancing；i/e//p
9、ushingtheconveyorfirst/andthenadvancingthesupport/WiththeIFSsystem/thesupportunitsisadvancedtotheconveyorimmediatelyafterthecuttingmachinehaspassed/andtheforwardcanopyofthesupportunitsislongenoughtothesupportboththerecentlyandnewlyexposedroofsections/Afterthesupportshavebeenadvanced/theconveyorispus
10、hedover/FRAMETheframesupportisanextensionofthesinglehydraulicpropsconventionallyusedunderground/Thusitisthefirsttypedevelopedinmodernself-advancinghydraulicpoweredsupports/Itinvolvessettinguptwohydraulicpropsorlegsverticallyintandemthatareconnectedatthetopbyasingleortwosegmentedcanopies/Thetwosegmen
11、tedcanopiescanbehinge-jointedatanypointbetweenthelegsorinfrontofthefrontleg/Thebaseofthetwohydrauliclegsmaybeacircularsteelshoeweldedatbottomofeachlegorsolidbaseconnectingbothlegs/Generally/aframesupportconsistsoftwoorthreesetsofhydrauliclegs/Thesetmovingfirstisthesecondaryset/thesetmovinglateristhe
12、primaryset/Thereisadouble-actingraminstalledbetweeneachset/Thepistonoftheramisconnectedtothesecondarysetandthecylindertotheprimaryset/Duringsupportadvance/theprimarysetissetagainsttheroofwhilethesecondarysetisloweredandpushedforwardbythepiston/Havingreachedthenewposition/thesecondarysetisagainstther
13、oofwhiletheprimarysetisloweredandpulledforwardbythecylinder/Thedistanceofeachadvancerangesfrom20to36in/(0/500/91m)Theframesupportisverysimple/butmoreflexibleorlessstablestructurally/Thereareconsiderableuncoveredspacesbetweenthetwopiecesofcanopywhichallowsbrokenroofrocktofallthrough/Consequently/thef
14、ramesupportisnotsuitableforaweakroof/Frameshavebecomeseldomusedbecausetheyarelessstableandrequirefrequentmaintenance/CHOCKInachocksupport/thecanopyisasolidpieceandthebasemaybeeitherasolidorpieceortwoseparatepartsconnectedbysteelbarsattherearand/orthefrontends/Inbothcasesalargeopenspaceisleftatthecen
15、terforlocatingthedouble-actinghydraulicramwhichisusedtopushandpullthechainconveyorandthechockinawholeunit/respectively/adistinctivedifferencefromtheframesupport/Thissetupisalsousedintheshieldsandchockshields/Again/allhydrauliclegsareinstalledverticallybetweenthebaseandthecanopy/Thenumberoflegsranges
16、fromthreetosix/butthefour-legchocksarebyfarthemostpopularones/Thesix-legchocksaredesignedforthinseamswithtwolegsinthefrontandfourlegsintherear/separatedbyawalkway/Forthesix-legchocks/thecanopyisgenerallyhinge-jointedabovethewalkway/Mostchockarealsoequippedwithagobwindowhangingattherearendofthecanopy
17、/Thegobwindowconsistsofseveralrectangularsteelplatesconnectedhorizontallyatbothends/Inmostchocksupports/therearehingejointconnectionsbetweenthelegsandthecanopyandbetweenthelegsandthebase/Butinordertoincreasethelongitudinalstability/itisreinforcedmostlywithabox-shapedsteelframebetweenthebaseandeachle
18、g/Alegrestoringdeviceisinstalledaroundeachlegatthetopofthebox-shapedsteelframe/Thechocksaresuitableformediumtohardroof/Whentheroofoverhangswellintothegobandrequiresinducedcaving/thechockscanprovideaccesstothegob/SHIELDShields/anewentryintheearlyseventies/arecharacterizedbytheadditionofacavingshielda
19、ttherearendbetweenthebaseandthecanopy/Thecavingshields/whichingeneralareinclined/arehinge-jointedtothecanopyandthebasemakingtheshieldakinematicallystablesupport/amajoradvantageovertheframesandthechocks/Italsocompletelysealsoffthegobandpreventsrockdebrisfromgettingintothefacesideofthesupport/Thusthes
20、hield-supportedfaceisgenerallyclean/Thehydrauliclegsintheshieldsaregenerallyinclinedtoprovidemoreopenspacefortraffic/Becausethecanopy/cavingshield/andbaseareinterconnected/itcanwellresistthehorizontalforcewithoutbendingthelegs/Thus/unlikethesolidconstraintintheframe/chocksupports/thepinconnectionsbe
21、tweenthelegsandthecanopy/andbetweenthelegsandthebaseinashieldsupportmakeitpossiblethattheangleofinclinationofthehydrauliclegsvarieswiththeminingheights/Sinceonlytheverticalcomponentofhydrauliclegpressureisavailableforsupportingtheroof/theactualloadingcapacityoftheshieldalsovarieswiththeminingheights
22、/Therearemanyvariationsoftheshieldsupports/Inthefollowing/sixitemsareusedtoclassifytheshields/whichenablesaunifiedterminologytobedevelopedforallkindsofshields/Thetypesofmotionaltracesofthecanopytip/legpositionsandorientation/numberoflegs/canopygeometry/andotheroptionaldesignsanddevicescanbeclearlysp
23、ecifiedbytheterminology/TYPESOFMOTIONALTRACESFORTHELEADINGEDGEOFTHECANOPY/Thisisthemostcommonlyrecognizedwayofclassifyingtheshield/Basedonthiscriterion/therearethreetypes/lemniscate/caliper/andellipse/Lemniscate/Thisisthemostpopulartype/Thecavingshieldandthebasearejointedbytwolemniscatebarswhichhave
24、atotaloffourhinges/Asthehydrauliclegsareraisedandlowered/thedimentionsofthelemniscatebarsareselectedsuchthattheleadingedgeofthecanopymovesupanddownnearlyvertically/thusmaintaininganearlyconstantunsupporteddistancebetweentheface-lineandtheleadingedgeofthecanopy/Thisisafeaturethatiswidelyconsideredmos
25、tdesirableforgoodroofcontrol/Thereareclearlimitsofminingheightwithinwhichtheleadingedgeofthecanopymovesnearlyvertically/Theselimitsarestrictlycontrolledbythedimentionalandpositionalarrangementsofthecanopy/cavingshield/lemniscatebars/andthebase/Beyondtheselimits/theedgeswillmoverapidlyawayfromtheface
26、-linecreatingalargeunsupportedarea/Caliper/Inacalipershield/thecavingshieldandthebaseareconnectedbyasinglehinge/Whenthehydrauliclegsareraised/theleadingedgeofthecanopymovesinanarcawayfromtheface/thusincreasingtheunsupportedarea/Thisisconsideredbymostuserstheleastdesirablefeatureofthecalipershield/Bu
27、tinpracticeiftheseamthicknessvarieslittle/thedimentionalandpositionalarrangementofcanopy/cavingshield/andthebasecanbesodesignedthatthedistancechangeofunsupportedareawillnotbesignificant/Ontheotherhand/whenthelegsarelowered/itreducestheunsupportedarea/Ellipse/Inthistypethecavingshieldandthebasearesoc
28、onnectedthatwhenthehydrauliclegsaremovedupanddown/theleadingedgeofthecanopyfollowsanellipticaltrace/Thistypeisseldomused/CHOCKSHIELDThechockshieldcombinesthefeaturesofthechocksandtheshields/Assuchitpossessestheadvantagesofboth/Ifallofthefourorsixlegsareinstalledbetweenthecanopyandthebase/itiscalleda
29、chockshield/Thereareregularfourorsix-legchockshieldsinwhichalllegsareverticalandparallel/OthersformVorXshapes/Somecanopiesareasinglepieceandsomearetwopieceswithahydraulicramatthehingejoint/Thechockshieldhasthehighestsupportingefficiency/Theyaresuitableforhardroof/中文译文自移式液压支架现代长壁工作面采煤已经在开采区使用液压支架。液压支架不仅支撑顶板，推动刮板输送机工作面和自移式支架本身，而且还为相关的采煤设备提供一个安全的工作环境。因此正确的选择和应用液压支架是长壁工作面采煤成功的先决条件。此外，由于对液压支架需求数量很大，对液压支架的投资经常要占到长壁采煤工作面
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