煤矿英语-液压支架

煤矿英语-液压支架

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时间:2019-09-27

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1、9-1IntroductionModernlongwallminingemploysself-advancinghydraulicpoweredsupports[1](whichwillsimplybecalledpoweredsupportsinthisbook)atthefacearea.Thesupportsnotonlyholduptheroof,pushthefacechainconveyor(AFC),andadvancethemselves,butalsoprovideasafeenviro

2、nment[2]forallassociatedminingactivities.Thereforetheirsuccessfulselectionandapplicationaretheprerequisiteforsuccessfullongwallmining.Furthermore,duetothelargenumberofunitsrequired,thecapitalinvestedforthepoweredsupportsusuallyaccountsformorethanhalfofthe

3、initialcapitalforalongwallface.Thereforebothfromtechnicalandeconomicpointsofview,thepoweredsupportsareveryimportantpieceofequipmentinalongwallface.9-2ClassificationofPoweredSupportTheapplicationofmodernpoweredsupportscanbetracedbacktotheearly1950s.Sinceth

4、en,followingtheiradoptionineverypartoftheworld,therehavebeencountlessmodelsdesignedandmanufacturedinvariouscountries.Butunfortunatelytherestillisnouniformsystemofclassification.Inthissectionasimplifiedclassificationisused.Sinceapoweredsupportconsistsoffou

5、rmajorcomponents(i.e.,canopy,cavingshield,hydrauliclegsorprops,andbaseplate),thewaysbywhichtheyareinterrelatedareusedforclassification.Inthisrespect,twofactorsaremostimportant:(1)presenceorabsenceofacavingshield[3]—ifacavingshieldisincluded,thesupportisa“

6、shield”type,otherwiseitisaframeorachock;(2)numberandtypeofarrangingthehydrauliclegs[4]—sincesupportcapacityisgenerallyproportionaltothenumberofhydrauliclegs,itisimportanttospecifythenumberofhydrauliclegsthatasupporthas.Furthermorethewaythehydrauliclegsare

7、installedisimportant;forexample,averticalinstallationbetweenthebaseandthecanopyhasthehighestefficiencyofapplicationwhereasaninclinedinstallationbetweenthebaseandthecavingshieldhastheleastefficiencyinsupportingtheroof.Basedonthisconcept,therearefourtypesof

8、poweredsupports,thoseare,frame[5],chock[6],shield[7],andchockshield[8],inorderofevolutionoftheirdevelopment.However,itmustbenotedthatthetrendoftheirdevelopmentineachtypeissuchthatitbecomeslessdistinguishableintermso

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