外文翻譯--自移式液壓支架-液壓系統(tǒng)(存儲版)
【正文】 large number of units required, the capital invested for the power support usually accounts for more than half of the initial capital for a longwall face. Therefore both from technical and economic points of view, the powered support is a very important piece of equipment in a long wall face. The application of modern powered supports can be traced back to early 1950’s. Since then, following its adoption in every part of the world, there have been countless models design and manufactured in various countries. But unfortunately, there still is no uniform system of classification. A simplified classification is used in this section. Since a powered support consists of four major ponents(i. e. , canopy, caving shield, hydraulic legs and props, and base plate), the ways by which they are interrelated are used for classification. In this respect, two factors are most important: (1) presence or absence of caving shield if a caving shield is included, the support is a “shield” type, otherwise, a frame or a chock。因此，從技術(shù)和經(jīng)濟兩方面的觀點看，液壓支架是長壁采煤工作面設(shè)備中十分重要的一部分。另外，液壓支柱的 安裝方式也很重要，例如，立柱垂直安裝在底座和有掩護梁的頂梁之間，此時對頂板具有最小的支護效率。 對于即時支護方式，液壓支架在截煤機過去之后立即跟隨刮板輸送機前進，液壓支架前面的頂板有足夠的長度來支護采過和將要采的頂板部分。先移動的是次要裝置，后移動的是主要裝置。兩塊頂板下有相當大的未覆蓋區(qū)域，這段區(qū)域允許碎石落入。六柱式垛式支架是為薄煤層設(shè)計的，兩個支柱在前，四個在后，中間是人行走的通道。當部分頂板已經(jīng)完全懸掛在采空區(qū)時，需要引導(dǎo)其塌落，這時垛式液壓支架就可以提供一條通向采空區(qū)的通道。由于只有液壓立柱的垂直分量 起支護頂板的作用，掩護式液壓支架的承載能力隨著采煤高度的變化而變化。隨著掩護式液壓支架立柱的升起和下降，選擇好雙紐線桿的尺寸，就可以使頂梁前端近乎垂直的作上升和下降運動，這樣就可以保持頂梁前端與煤壁之間未支撐的距離為一常量，這種特性對很好控制頂板來說是廣泛考慮的最合乎要求的。另外，當降低液壓支柱時，未支護面積將會減少。有些頂梁是一個整體，而有些頂梁則是由通過鉸接并在鉸接處安裝一液壓千斤頂?shù)膬刹糠纸M成的。所以，支撐掩護式液壓支架具有以上兩者所具有的優(yōu)點。 圓弧形：在圓弧形掩護式液壓支架中，掩護梁和底座之間通 過單一的鉸接連接。 頂梁端部的運動軌跡的形式 這是公認的最普遍的對掩護是液壓支架的分類方法。因此，掩護式液壓支架的工作面一般都比較清潔。 在大多數(shù)垛式支架中，液壓支柱與頂梁和液壓支柱與底座之間都采用鉸接式連接。在這兩種情況下， 兩垛式支架之間將有一個很大的空間，并在其中部安裝雙作用立柱，這種立柱將把刮板輸送機和垛式液壓支架作為一個整體進行推移，這就是垛式液壓支架與節(jié)式液壓支架的不同。當?shù)竭_新位置以后，次要支柱支撐頂板，主要 支柱降低并且由缸筒拉動前進。它包括一前一后垂直安裝的支柱，支 柱連接在單一或分割的頂梁的頂端。 對于標準支護方式，采煤機作切割或分段運動，工作面輸送機由裝在液壓支架上的推移千斤頂推動前進。 這里使用一個簡化的液壓支架的分類。 i. e. , pushing the conveyor first, and then advancing the support. With the IFS system, the support units is advanced to the conveyor immediately after the cutting machine has passed, and the forward canopy of the support units is long enough to the support both the recently and newly exposed roof sections. After the supports have been advanced, the conveyor is pushed over. FRAME The frame support is an extension of the single hydraulic props conventionally used underground. Thus it is the first type developed in modern selfadvancing hydraulic powered supports. It involves setting up two hydraulic props or legs vertically in tandem that are connected at the top by a single or two segmented canopies. The two segmented canopies can be hingejointed at any point between the legs or in front of the fro
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