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机械毕业设计英文翻译文献翻译
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机械毕业设计英文外文翻译53采煤机,机械毕业设计英文翻译文献翻译
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附录 1： 英文原文 SHEARERS INTRODUCTION Longwall mining in the United States is finally beginning to carve out a significant percentage of underground mining tonnage. Although longwall installations are continuing throughout the country at last count in eleven statesthe concentration is in the Eastern coal fields, with West Virginia leading all states. As a result of increased experience with longwall installations under different condition, certain improvements are being made. For instance, roof support shields are being utilized to a greater extent, and ruggedness is being stressed in all areas. Modifications are being considered in order to use the longwall in other types of seams and seam conditions. Evidently longwall users like the results that they have been getting because they have been installing more systems. Since longwall mining is obviously going to play a much larger role in the coal mining industry in the future, there is a great need for a comprehensive book that presents, systematically, every major subject in longwall mining. More than a decade of modern longwall mining in the United States has demonstrated that it is inherently safe and complies easily with current laws. It is also highly productive, provided it is properly designed and operated. However, the growth of longwall mining, though steady, has been slow. One of the reasons for this is the lack of a comprehensive technical background literature for training purposes. This book attempts to fill such a gap. For the first time, anyone who would like to learn more about longwall mining can find all of the major topics in one book. Thus, this book is a milestone in the development of longwall mining. SHEARERS Longwall equipment consists of three major components: the hydraulically powered roof support, the chain conveyor, and the coal-cutting machine. The two different types of coal-cutting equipment used in coal mines are shearers and plows. Plows are used in low seams, 42in. or less. The unit consists of steel construction equipped with carbon-tipped bits. This passive steel unit is engaged to a guiding system on the face conveyor. An endless round link chain powered by ntssynchronized electric drives on each end of the face conveyor pulls the plow body at speeds between 120 and 420 ft/min along the face. For the cutting process the plow has to be forced against the coal face. This is done by hydraulic cylinder attached to the gob side of the face conveyor and to the base of the supports, or by a separate hydraulic prop. Forces of between 1and 3 tons are applied per cylinder. A plow drive is attached to each drive frame of the face conveyor. Only 30% to 60% of the drive power supplied to the plow is used for cutting and loading of coal; the remainder is lost in friction. This means that the power loss is considerably higher than that of a shearer, which uses 75% to 85% of its power for the removal of the coal. As a result, rather large drives are required at the face ends. Although there are many models, the shearer has several common basic components. A double-ended ranging-drum shearer (Fig. 8. 1), for example, consists of four major components: electric motors, gearheads, haulage unit (power pack), and cutting drums. The electric motor ranging from 300 to 1000 hp. (223-750kw)is the power source for the shearer. It provides power to run the hydraulic pumps in the haulage unit and the gearheads for the cutting drum. The large capacity shearers are generally equipped with two electric motors: one of the haulage unit and one gearhead and the other for the other gearhead and other ancillary equipment. The motors can be remotely controlled. There are two gearheads, one on the left-and the other on the right- hand side of the shearer. Each gearhead consists of a gearhead gearbox and a ranging arm. The cutting drum is laced with spiral vanes on which the cutting bits are mounted. Its diameter ranges from 34 to 72 in. (0.861.83m) with rotational speeds from 30 to 105 rpm. The trends are toward fewer but larger bits and slower drum speed for better cutting efficiency and less coal dust production. The drums are also equipped with power cowls to increase the coal loading efficiency. The power cowl is usually located behind the cutting drum. For that reason, it can be rotated a full 180. The electric motor, haulage unit, and gearhead boxes combine to form the ntsshearers body which is mounted on the underframe. The underframe has four sliding shoes. The face-side shoes are fitted and ride on the face-side top guide of the face conveyor pan, and the other two gob-side sliding shoes are fitted on a guide tube to prevent derailment. The reaming speed of the shearer ranges from 19 to 46 ft/min(5.8-14.0m/min). In addition, the shearer is equipped with auxiliary hydraulic pumps and control valves for operating the ranging arms and power cowls, water spraying devices, cable, chain anchorage and tensioners, and so on. TYPES OF MODERN SHEARERS Since its first appearance in 1954, the shearer has undergone continuous changes both in capability and structure. It is now the major cutting machine in longwall coal faces. There are two types of shearers, single- and double- drum. In the earlier models, the drum in the single-drum shearer is mounted on the shearers body and cannot be adjusted for height. Therefore it is not suitable for areas where there are constant changes in seam thickness and floor undulation. Thus, the single-ended fixed-drum shearer is used mostly for thin seams. In order to accommodate the changing of seam thickness and floor undulation the single-drum shearers with a ranging arm are used. The ranging arm can be raised up and down by hydraulic control devices. But when the seam exceeds a certain thickness, the shearer cannot cut the entire seam height in one cut and a return cutting trip is necessary to complete a full web cut. Furthermore, since the drum is located on the headentry side, it generally requires a niche in the tail entry side. A niche is precut face end, one web deep and a shearers length long. With a niche at the face end the shearer can turn around. Nowadays, the double ranging-drum shearers are used predominantly. The shearer cuts the whole seam height in one trip. The two drums can be positioned to any required height (within the designed range) during cutting and lowered well below the floor level. The arrangement of the drums enables the whole seam to be cut in either direction of travel, thereby ensuring rapid face advance and shortening roof exposure time. There are various types of double ranging-drum shearers. Based on the location of the drums, there are two types: one with one drum mounted on each side of the shearers body and the other with both drums mounted on one side of the machine. The former type is the most widely used. Its advantage is that with one drum on each side of the shearer, it can sump in either direction. During the cutting trip, the leading drum cuts the upper 70% of the seam height while the rear drum cuts the lower 30% and cleans up the broken coal on the floor. The two drums are approximately 23-33 ft. (7-10m) apart. When the shearer is traveling in the ntsopposite direction to that of the face conveyor, the coal cut by the leading drum has to pass under the shearers body, which increases the moving resistance of the shearer and the face conveyor and could cause a “crowding” condition. If the broken coal is too large, it may block the shearer and stop the operation. In general, when the shearer and face conveyor are traveling in the opposite directions, approximately 70% of the coal taken by the leading drum will pass under the shearer. But when they are traveling in the same direction, the coal taken down by the rear drum together with the float coal from the floor constitute the approximately 30% of the coal that has to pass under the shearer. The former case consumes 25% more power than the latter. As compared to the single- ended shearer, the underframe of the double-ended shearer is higher, thereby ensuring a sufficient cross section for coal passage. Based on the method of adjusting the height of the cutting drum, there are also two types of shearers: ranging-arm shearer and gearhead shearer. The former one is commonly used, whereas the latter one is a recent development. The advantage of the gearhead shearer(Fig. 8.2)is that the haulage unit is located at the center of the shearers body and mounted on the underframe. On both sides of the haulage unit, there is a gearhead. Each gearhead contains an electric motor and a speed-reduction unit. The gearhead is raised and lowered by a hydraulic ram. The adjustable range of cutting height can reach up to 4.6 ft. In selecting the shearer, mining height should first be considered; that is, the diameter of the cutting drum, body height, length of the ranging arm, and swing angle must be properly selected. For the double-ended ranging-drum shearer, the maximum mining height cannot exceed twice the diameter of the cutting drum. The mining height can be determined by (Fig.8.3) H=Hb-B/2+Lsin+D/2 8.1 Where H=seam thickness or mining height Hb=shearers body height B=body depth L=length of the ranging arm nts=the angle between the ranging arm and the horizontal line when the ranging arm is raised to its maximum height D=diameter of the cutting drum For example, for the Eichhoff EDW-170 L double ranging-drum shearer, Hb=4.3 ft, L=3.90 ft, =52， and D=5.3 ft. Its maximum cutting height is H=9.2 ft. CHAIN HAULAGE There are two types of shearer haulage: chain and chainless. Haulage of shearers was initially by means of short flexible steel ropes. This method of hauling power loading machines was short lived and was replaced by full-face length flexible steel ropes of a small diameter multi-core construction. The replacement of the flexible steel rope with haulage chain in the 1960s quickly found favour and, initially, a considerable improvement was apparent in both safety and efficiency. The haulage chain is a round link chain extended along the whole face and fixed on both ends at the head and tail drives of the face chain conveyor, respectively. The chain also passes through the driving and deflecting (or guiding) sprockets in the haulage unit of the shearer. As the driving sprocket rotates, its teeth trap to the matching chain links and move along the nonmoving haulage chain, thereby pulling the shearer along.(Fig.8.4) When the driving sprocket rotates counterclockwise, the shearer moves to the right. Conversely, the shearer moves to the left. The part of the chain in front of the moving shearer is generally tight or on the tensioned side whereas the other side, behind the moving shearer, is slack or on the slack side. nts 中文译文 采煤机 介绍 在美国长壁工作面采煤正在开始最后开采地下采煤吨位的一个重要百分比。虽然长壁工作面安装正在国家各处持续 最后把十一州计算在内 集中在东部煤田中，领先所有州的维吉尼亚西部。 作为通过在不同情况下安装长壁工作面增加经验的结果，特殊的成果正在出现。举例来说，支架正在被利用到一个更广泛的程度，而且在所有区域中强调坚固。正在考虑改进，以便在其他类型的煤层和煤况下使用长壁工作面。明显地长壁工作面的使用者喜欢这个他们一直得到的结果，因为他们一直安装更多的系统。因为在未来的采矿业长壁工作面采煤显然将要扮演一个非常重要的角 色 ，强烈的需要有一本全面的系统地阐述采矿的每一个重要主题的书籍。 在美国十多年的实践，证实了长壁工作面采煤在本质上是安全的，且比较容易遵守现行的法律。假如适当地设计并操作它，它也是高产的。然而，长壁工作面采煤的增长，虽然平稳，但是缓慢。其中一个原因是以实践为目的的全面技术背景著作的缺乏。这本书尝试去填补这个空白。 第一次，任何一个想要更多的了解关个于长壁工作面采煤的人，能够在一本书中找到所有的重要主题。因此，这本书是长壁工作面采煤发展史上的里程碑。 滚筒式采煤机 长壁工作面的设备包含三个主要的部分：液压支 架，刮板运输机，和破碎机。 被用于煤矿的两种不同类型的切煤设备是滚筒式采煤机和刨煤机。 刨煤机被用于低煤层， 42 英寸或者更少。这个物体由渗碳的刀尖装备的齿轮组织组成。这个钝化的齿轮单位与工作面输送机上的一个指挥系统相连。由位于工作面输送机两端的同步电机驱动的无级圆环链，牵引刨体以每分 120 至 420英尺的速度沿工作面移动。 nts对于切割进程，刨煤机必须被强迫对抗煤层表面。由液压油缸到工作面运输机的采空区和支持的底部，或者由一个独立的液压支柱。每一个油缸 1至 3吨的对抗力。 一个运行中的刨煤机工作面运输机的每一个运行 框架。运行力只有 30%到 60%提供给刨煤机，被用来切割和引导煤；剩余部分在摩擦中消耗。意思就是说其动力消耗被认为高于使用 75%到 85%的力用于煤的切割的滚筒式采煤机。结果，在工作面机尾就需要相当大的运行力。 虽然有许多类型，但是滚筒式采煤机有几种常见的基本部分。举例来说，一台双滚筒可调高摇臂采煤机（图 8.1），由四个主要部分组成：电动马达，机头，牵引部分（电动机），和截割部。 电动马达范围从 300 到 1000 马力。（ 223-750 千瓦）是滚筒式采煤机的电源。它提供动力来运行牵引部分的液压泵和截割部的机头。大功 率滚筒式采煤机通常装备两个电动马达：一个用于牵引部分和一个机头，另一个用于另一个机头和其他的辅助设备。马达可以远程控制。 有两个机头，一个在滚筒式采煤机的左边，另一个在右边。每一个机头都由一个机头减速器和一个摇臂组成。 截割部在装备切割刀尖的位置与螺旋叶片相连。它的直径范围从 34 到 72英寸（ 0.86 1.83 米）旋转速度从 30 到 105 转 /每分。趋势是更少的但是更大的刀尖和比较慢的滚筒速度以获得更好的切割效率和更少的煤灰尘产物。滚筒也装备挡煤板以便提高落煤效率。挡煤板常位于截割部之后。因此，能旋转 180。 电动马达，牵引部分，和机头箱联合形成被装在机架上的滚筒式采煤机的主体。机架有四个滑轮。表面的滑轮被安装在工作面运输机的导向架表面，另外两个滑轮被安装在导向管上以便避免脱轨。滚筒式采煤机的速度范围从 19 到 46英尺 /每分（ 5.8-14.0 米 /分）。 另外，滚筒式采煤机被装备辅助的液压泵和控制阀以便操作摇臂和电力装置，内喷雾装置，粗索，锚固和涨紧装置，等等。 先进滚筒式采煤机的类型 自从 1954 年它的一次出现以后，滚筒式采煤机在能力和结构方面都持续的发生变化。它在长壁工作面采煤中是主要的切割机器。有两种类型的滚筒式采煤机，单滚筒和双滚筒。在较早的类型中，在单滚筒式采煤机中的滚筒是装在滚筒式采煤机的主体部位的，并且不能调节高度。因此它对于煤层厚度和地面起伏不断改变的地区是不适应的。因此，单滚筒式采煤机大多用于薄煤层。 为了适应煤层厚度和地面起伏的不断变化，带一个摇臂的单滚筒式采煤机投入使用。摇臂可以由液压控制装置控制升高和降低。但是当煤层超过特定的厚度时，滚筒式采煤机不能在一次切割中切割 整个煤层高度，需要回返切割去完成一个完整的截深切割。此外，因为滚筒位于机头边上，它通常需要一个在尾部入口处的缺口。缺口在工作面尾部按规格切割，一个截深深度和一个滚筒式采煤机
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