1、英文原文POWERED SUPPORTSFUNCTIONSThe five main functions of a powered support are: 1. to resist vertical loading;2. to resist, or accommodate, lateral (horizontal) movement of the srtate;3, to provide protection from waste flushing;4. to advance the AFC;5. to be self-advancing.SYSTEM ARRANGEMENTSThe pow
2、ered supports are attached to the AFC at approved intervals. Each support has a ram for pushing over the AFC ；consequently, the operator has flexibility in deciding the number of rams to use for this operation.An essential feature of the system is the hydraulic feed arrangement, i e the flow and ret
3、urn lines(hoses)linking the supports with the power pack which is located in the gate clear of the face end. The hydraulic fluid is a mixture of oil(5%) and water(95%) and the hydraulic pressure used varies according to the requirements of the system, depending on number of supports,yield loads etc.
4、A typical pump capacity would be a pressure of between 1500 and 2000 1b p.s.i. and a flow of between 15 and 25 gallons a minute . The difference between pump input and system requirement at any moments is by-passed through an unloading valve.SEQUENCE OF OPERATIONS Because it is hydraulically operate
5、d, the powered support system can be controlled by one man, who operates a control valve to initiate the required movements of legs or ram.Control systems, whether “individual”, “adjacent” or “bank”, are explained in the next chapter. The sequence of operations for sdvancing the supports varies depe
6、nding on whether the conventional system or the immediate forward support(IFS) system is in use.IFS SYSTEM Here,the aim is to support the newly sxposed roof,behind the power loader, before the AFC is snaked ower.The sequence is: 1.web of coal is cut and loaded 2.powered support is released from the
7、roof 3.powered support is drawn forward 4.powered support is re-set to the roof 5.AFC is pushed forward. The advantage claimed for the immediate forward support system is that it fives quicker support to the newly exposed roof behind the power loader;this can be important with the IFS system the pow
8、ered supports stand the equivalent of one wed-width back from the AFC. Consequently, the supports are provided with longer roof canopies in order to extend over the conveyor to the coalface.CYCLE OF POWERED SUPPORT MOVEMENTS Whatever system of controlling powered support is employed, the operator mu
9、st initiate movement of units by means of a rotary control valve.The cycle of powered support movements is as fallow: Neutral No action Ram push To advance conveyor to new position Legs lower To release support from the roof Ram pull To advance support Legs raise To re-set support to the roof Neutra
10、l No action中文译文液压支架功能1、承受垂直负荷；2、承受或适应地层的水平位移； 3、抵挡来自采空区的碎石；4、推移输送机；5、自行前移。液压系统的布置液压支架已“适当的”间隔与输送机连接在一起。每个支架单元各有一个千斤顶推移输送机；应此，操作人员可以灵活地决定开动哪一台千斤顶来完成此项推移工作。液压系统的一个重要问题是液力馈送的布置，也就是供流及回流线路（软管）怎样把支架和动力部分连接起来的问题，动力部分应安置在平巷、稍稍离开工作面端头的地方。传压液体是油（5%）与水（95%）的混合物，所用压力随系统的要求而有所不同，取决于支架数、承受载荷等。 一台典型液压系统的能力是每平方英寸1
11、5002000磅的压力和每分钟1520加仑的流量。液力泵的输入流量比支架系统实际需要流量多的部分随时都可以通过卸载阀从旁路流通。操作顺序 因为是液压传动，所以整个支架系统可以由一个人操作，他操纵一个控制阀来立柱和千斤顶进行所需的动作。不同的控制方法，无论是“单架控制”，或是“邻架控制”及“分组控制”，都将在下面加以解释。移支架的操纵顺序有所不同，这取决于究竟是采用普通的系统还是采用立即支护前方的支架系统。即时支护系统这种系统的目的是采煤机走过之后、输送机未移之前、立即支护新裸露的顶板，其顺序如下：1、完成一个截深的煤炭采装2、液压支架从顶板降下3、液压支架拉向前方4、液压支架重新支撑顶板5、输送机向前推移即时支护系统的优点是采煤机走过之后新裸露的顶板迅速地得到支护，对于条件不好的顶板，这一点可能很重要。必须注意的是，对于即时支护系统，液压支架位于输送机后面一个截深之后。因此，此类支架配备较长的顶板，以便伸出到采煤机工作面的输送机之上。液压支架的动作循环液压支架无论使用哪种控制方法，操纵者都要使用旋转控制阀来启动或是单个支架，或是一组支架。液压支架的动作循环如下：空挡 无动作推千斤顶 把输送机前移至新的位置降柱 把支架放开对顶板的支撑拉千斤顶 把支架移向前方升柱 使支架重新支撑顶板空挡 无动作
