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下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 1 -本 科 毕 业 设 计（论文）题目 低位放顶煤液压支架 院（系部）专业名称 年级班级 学生姓名 指导教师 下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 2 -摘 要现代煤矿高效工作面的关键设备液压支架 ,是煤矿实现采煤、运输和支护等所有工序全部机械化的重要环节。支撑掩护式支架是以支撑为主 ,掩护为辅的液压支架 ,用来控制采场顶板下沉断裂及冒落 ,保证控顶距内顶板完整和必要的回采空间。本设计从保证支架的合理工作状态 ,应尽量缩短降架时间 ,快速移架 ,及时支护等方面对支撑掩护式液压支架的结构特点及合理应用等进行了分析。在详细分析液压支架初撑力与直接顶相互作用机理的基础上,对支架合理初撑力的确定进行了分析研究,并提出了合理支架初撑力的确定方法。关键词：液压支架 支护 初撑力下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 3 -ABSTRACThe hydraulic support is the key equipment in todays high production faces underground,it is importantStanding shield hydraulic support can control the subsidence,rupture and inbreak of the stope roof,and assure the integrity of the roof and necessary extraction space.The structural feature and its rational application of standing shield hydraulic are introduced in brief.According to the paper,it is necessary to reduce the time of falling support,to move support quickly,to timber the roof in time and keep enough setting pressure. On the basis of analysis of the reciprocity mechanism of original pressure and direct roof, the author analyzes the setting methods of appropriate original pressure of powered support is put forward finally.Keywords: hydraulic support shoring put forward finally下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 4 -目 录前言 （6）1 绪论 （7）1.1 液压支架的作用及发展历史 （7）1.2 设计目的 （13）1.3 设计要求 （14）1.4 放顶煤液压支架的分类 （14）1.5 低位放顶煤液压支架的特点 （15）1.6 低位放顶煤液压支架的适应性 （16）1.7 低位放顶煤液压支架的主要结构 （17）2 液压支架的结构设计 （29）2.1 液压支架的选型 （29）2.2 主要设计参下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 5 -数 （32）2.3 液压支架的结构设计 （35）2.4 拟定液压系统 （52）3 支架的强度计算 （55）3.1 支架的工作状态 （55）3.2 支架载荷的确定 （55）3.3 支架的受力分析 （56）3.4 支架受力的影响因素 （76）3.5 强度条件 （77）4 液压支架的使用和维护 （80）4.1 液压支架操作 （80）4.2 液压支架操作维护要下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 6 -求 （81）4.3 液压支架操作管理事项 （81）5 液压支架常见故障及其排除 （83）5.1 结构件和连接销轴 （83）5.2 液压系统及液压元件 （83）5.3 支架在操作和支护过程中的故障 （84）结论 （86）致谢 （87）参考文献 （88）下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 7 -下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 8 -前 言毕业设计作为本科学习最重要的组成部分之一，它能提高我们发现、分析、解决问题的能力，综合检验和巩固我们所学知识，同时又是对我们大学四年所学知识的全面复习，更是向我们以后即将从事的专业性工作的正常过渡。放顶煤综采近年来在我国得到迅速的发展.放顶煤综采技术的推广使用,扩大了综合机械化开采的使用范围,简化了矿井的采掘系统和生产组织,大幅度里提高了综采工作面的劳动效率和生产,降低了煤炭的生产成本,在煤炭生产上取得了显著的技术经济效果.尽管我国在综采放顶煤技术的发展和放顶煤综采设备的研制上已取得了很大成绩,但仍然存在一些重大的技术问题没有得到切底解决,如煤炭回收率问题,工作面降、灭尘问题,采空区发火问题等,幸运的是在这次设计中我的课题就是关于煤矿采煤设备的液压支架，能更进一步的了解矿山机械。在设计过程中，得到了杨志波老师的关心和大力帮助，才得以顺利完成，在此表示衷心的感谢。同时，此设计有的内容尚需进一步在实践中验证，加之本人水平所限，设计中有不足之处，敬请指导老师批评指正。下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 9 -1 绪 论1.1 液压支架的作用及发展历史1.1.1 液压支架的应用及意义随着工业技术的不断发展，国民经济对煤炭需要量的日益增加，煤矿开采，特别是采煤工作免得生产技术面貌发生了巨大的变化。自 1954 年英国装备了世界上第一个液压支架工作面开始，采煤技术实现了综合机械化。综合机械化采煤，就是工作面采煤，运输和支护三大主要生产环节都实现机械化。也就是说，采用滚筒式或刨削式等采煤机械落煤与装煤；工作面重型可弯曲运输机，以及与之适应的顺槽转载机和可伸缩皮带运输机等运煤；自移式液压支架支护和管理顶板。这几种设备相互配合，组成了综合机械化采煤设备。液压支架是以高压液体为动力，由若干液压元件（油缸和滑件）与一些金属结构件组合而成的一种支撑和控制顶板的采煤工作面设备，能实现支撑，降落移架和推移运输机等一整套工序。液压支架技术上先进，经济上合理，安全上可靠，当前世界各国都在不断地提高采煤工作面的综合机械化水平。我国于 1964 年开始研制液压支架，已先后试制了 MZ-1928 型,TZ 型,BZZC型,WKM-400 型,DM-400 型,YZ 型,ZYZ 型,ZY 型等多种形式的液压支架，并在开滦，大同，阳泉，鹤壁，徐州，铜川，义马，淮北等局矿进行了试验和使用，取得了较好的效果。1974 年以来，从西德，英国，前苏联和波兰等国引进了许多不同类型的液压支架。实践证明，液压支架具有强度高，支护性能好，移设速度快，安全可靠等优点，能使采煤工作面达到高产量，高回采率和高工效，能大大减轻劳动强度，降低成本和掘进率，实现安全生产。1.1.2 国外放顶煤液压支架下载后包含有 CAD 图纸和说明书,咨询 Q 197216396 或 11970985- 10 -放顶煤支架是随着放顶煤开采方法应用而生的，综合机械化开采应用到放顶煤开采工作面后，使放顶煤开采技术进入了一个新的发展阶段。由于工作面由液压支架实现可靠、快速的支护，采用采煤机或刨煤机采煤，放顶煤作业在安全可靠的工作条件下进行，从而使工作面产量有明显提高。近年来，综采放顶煤技术在我国得到了迅速的发展和广泛的普及，综采放顶煤正成为一种高产高效的采煤方法。1957 年，前苏联研制出 KTY 型单输送机掩护式放顶煤液压支架，并在库兹巴斯煤田的托姆乌辛斯克矿使用，开采该矿的 2 号和 45 号煤层。煤厚为912m，煤层倾角 518，该放顶煤工作面为预先开采顶层煤铺设人工假顶，然后再采底煤。1963 年，法国研制出用于放顶煤开采的支撑掩护式放顶煤液压支架，并且于 1964 年在布朗齐矿区试验成功。该支架为四柱式，尾梁呈“香蕉”型，其摆动角度由千斤顶控制，配有两台输送机，第二台输送机安置于尾梁后部的底板上。放落的煤由第二台输送机运输，结构如图 1.1。图 1.1“香蕉”型放顶煤液压支架自 70 年代开始，法国、前西德、英国等国家陆续成功研制成功了“开天窗”的支撑掩护式或带插板的支撑式放顶煤液压支架。英国研制的“开天窗”式放顶煤液压支架在掩护梁上开了放顶煤“天窗” ，由液压千斤顶控制开关，“天窗”附近设有搅动杆，以便于冒落顶煤，掩护梁上还有钻眼孔，供煤硬不落时打眼放炮。第二台输送机安置在支架后部底座上，结构如图 1.2。外文原稿：Anhydrous Ammonia Pressure Vessels In The Pulp And Paper IndustryThe purpose of this article is to ensure that pulp and paper operating companies, their engineering consultants, and inspection contractors are informed about stress corrosion cracking in anhydrous ammonia service. The information was written by a task group of the TAPPI Engineering Division Nondestructive Testing and Quality Control Subcommittee.Bacteria in some activated sludge effluent treatment systems require supplementary food. In some cases, this food is provided by ammonia and phosphoric acid which are stored on the mill site. Ammonia is commonly stored as anhydrous liquid ammonia in carbon steel vessels at ambient temperature and 16 bar (250 psig) pressure.These vessels can be subject to stress corrosion cracking (SCC).SCC could cause release of ammonia, which is a hazardous chemical. SCC of carbon steel vessels in anhydrous ammonia service is somewhat analogous to that experienced in continuous digesters. For example, the importances of stress relief during fabrication and of in-service inspection are common to both.This article concerns storage in horizontal pressure vessels at ambient temperature, as this type of vessel is used in pulp and paper applications. Large refrigerated storage tanks are used for atmospheric pressure storage in the chemical industry.History of Scc In Ammonia Storage VesselsThe history of SCC in carbon steel ammonia storage vessels was reviewed by Loginow (1) and is also briefly summarized in a NACE Technical Committee Report entitled “Integrity of Equipment in Anhydrous Ammonia Storage and Handling” (2). In the 1950s, liquefied ammonia began to be injected directly into soil for fertilization. Failure of carbon steel storage vessels by SCC began to occur. These failures were unexpected since liquefied ammonia had been used for many years in the refrigeration, chemical, and metal heat treating industries without reported problems.Investigation confirmed SCC to be the cause of cracking. Three recommendations were made in 1962 that still form the basis of modern codes: Pressure vessels should be fully stress relieved. Extreme care should be used to eliminate oxygen from ammonia systems. Ammonia should contain at least 0.2% water to inhibit SCC.Loginow reported that adoption of these recommendations practically eliminated SCC in carbon steel vessels in the agriculture industry. However, in a recent Western Canadian survey SCC was found in 100 of 117 field storage vessels inspected by wet fluorescent magnetic particle testing (WFMT) (3).Despite the above measures SCC continued to occur in road transport tanks constructed from high strength steels, in refrigerated storage vessels and in vessels which had been weld repaired but not subsequently stress relieved. An additional recommendation to limit steel tensile or yield strength was embodied in the U.S. and British ammonia storage codes, respectively (4, 5). ANSI K61.1Nominal tensile no greater than 70,000 psi (580 MPa) U.K. CodeMinimum specified yield strength shall not exceed 350 MPa (51,000 psi).PRACTICAL CONSIDERATIONSThis article is concerned mainly with practical considerations important to pulp and paper mills already possessing anhydrous ammonia storage vessels or planning to fabricate such vessels. In view of the industrys experience with SCC in continuous digesters the governing objectives should be to control fabrication and inspection to prevent, or at least minimize, in-service problems including over-reaction to relatively minor crack indications. Guidance is available in the published codes and detailed information is available from some ammonia suppliers.FabricationThe two main objectives in fabrication should be to provide the most crack resistant vessel possible at reasonable cost and to ensure that an adequate inspection baseline is available for interpretation of subsequent in-service inspections.ASME Section VIII Division 1 does not require stress relief for anhydrous ammonia storage pressure vessels unless the owner specifies a lethal service designation.The lethal service designation requires radiographic testing (RT) of all butt welded joints plus post weld heat treatment.ANSI K-61.1-1989, “American National Standard Safety Requirements for the Storage and Handling of Anhydrous Ammonia,” adds several requirements: Fabrication to ASME Section VIII Division 1 Table UW 12 at a joint efficiency less than 80% is not allowed. Inspection and testing under UG-90(c) (2) (multiple, duplicate pressure vessel fabrication) is not allowed. Steel used for pressure containing parts shall have a nominal tensile strength no greater than 580MPa (70,000 psi). The minimum design pressure for ambient temperature storage shall be 16 bar (250 psig). Post weld heat treatment is mandatory and a furnace of sufficient size to accommodate the entire vessel is recommended. Welded attachments may be made to pads after post weld heat treatment. Horizontal vessels shall be mounted on saddles which extend over at least one third of the shells circumference. Thermal expansion and contraction shall be allowed for and means provided to prevent corrosion between the shell and the saddles.The 1986 British Code “Storage of Anhydrous Ammonia under Pressure in the United Kingdom” requires: Steel must have specified minimum yield strength less than 350 MPa (51,000 psi). Weld filler must have minimal strength overmatch compared with the base plate. 100% magnetic particle inspection of all internal welds in order to provide a record against which all future inspections of the vessel can be assessed. No welding is permitted after stress relief without subsequent local stress relief. Concrete saddles are prohibited. Support must be on continuously welded steel saddles attached before stress relief.Although the British Code does not state that magneti particle inspection should be by WFMT it is generally agreed that WFMT is the most sensitive technique and should be used for inspection of ammonia storage vessels. All inspection should be performed by qualified technicians. SNT-TC-1A Level II is a recommended minimum.One pulp and paper company has added the following requirements for fabrication of such vessels: Incorporation of a “corrosion allowance” of at least 1.6 mm (1/16 in.) to permit minor defect chasing during in-service inspections and to provide a margin against pitting which may occur if water is allowed to enter an out of service vessel. All weld toes profiled by grinding prior to wet fluorescent magnetic particle testing (WFMT). All WFMT indications greater than 1.6 mm (1/16 in.) to be removed by grinding before post weld heat treatment. Shear wave ultrasonic testing (UT) of nozzle-to-shell welds permitted if RT is judged impractical. WFMT to be repeated after final hydrotest test of the vessel and the report retained by the owner. Vessel to be dried completely after hydrotest test and nitrogen padded until filled with ammonia.Valves, piping, and fittingsBoth the ANSI and U.K. codes address piping, valves, and fittings. A detailed summary is beyond the scope of this article, but some points are worth noting. ANSI K61.1 requires all nonrefrigerated ammonia piping to meet the requirements of ANSI/ASME B31.3 “Chemical Plant and Petroleum Refinery Piping.” The U.K. Code states copper and copper bearing alloys shall not be used.ANSI/ASME B31.3 requires a minimum of 5% of piping welds be radiographically tested. Valves and other apparatus should be rated for ammonia service and should not contain copper or copper alloy components.In one case, a nickel rupture disc corroded to failure at its periphery due to formation of an ammonia solution at a gasketed joint exposed to the weather.In-service inspectionVessel entry Liquid or gaseous ammonia is hazardous and in some jurisdictions release of ammonia vapor to the atmosphere is prohibited by law. Vessels must be properly purged by water and/or steam. Detailed procedures for vessel purging and entry are available from ammonia suppliers (6).Inspection procedures The ANSI standard does not address in-service inspection but does state weld repair or alteration must conform to the current edition of the National Board Inspection Code (NBIC).The 1992 edition of the NBIC includes nonmandatory guidelines for inspection of liquid ammonia vessels (7).These guidelines recommend: Power buffing or light sandblasting as surface preparation for inspection All interior welds be examined by WFMT. Cracks should be removed by grinding without encroaching on the minimum thickness required by ASME Section VIII and the original design. Weld repairs, regardless of size, should be post weld heat treated wherever possible.Light grinding does increase the sensitivity of WFMT compared to sandblasting or power buffing (8). For example the NBIC mandates grinding as surface preparation for deaerator inspection. The omission of grinding in the guidelines for ammonia vessel in-service inspection may be due to concern that rough grinding may produce residual stress sufficient to initiate SCC in anhydrous ammonia service. If welds have been properly profiled for WFMT on initial fabrication, then grinding for in-service inspection should not be needed.The NBIC guidelines also state that other inspection methods such as acoustic emission or ultrasonics may be used and that fracture mechanics may be used to assess the integrity of vessels where complete removal of cracks is not practical.Normally the only corrosion that occurs in anhydrous ammonia vessels is due to water ingress during out of service periods. Shallow pitting, however, has been found in the bottom of some vessels beneath oily deposits. The source of oil is presumed to be from compressors used to handle the ammonia.In view of concerns over air contamination due to vessel entry and residual stress imparted by grinding nonintrusive inspection, techniques like acoustic emission and UT could be considered by vessel owners. The British Code does not mention nonintrusive inspection of ambient temperature pressure vessels but does state that, if acoustic emission is to be used for spherical storage vessels, a reference base should be taken during initial hydrotesting. Nonintrusive inspection is being used in other industries (9).Vessel refilling Safety procedures should be established for refilling a vessel that has been emptied for inspection. It is also very important to purge the vessel of air to prevent the occurrence of SCC. Detailed instructions are available from ammonia suppliers (10). If a vessel is not to be returned to service immediately after inspection, then care should be taken to dry it and possibly nitrogen-pad it depending on the time it will remain out of service.Inspection frequency Neither the ANSI document nor the NBIC deals with inspection frequency. The British Code recommends the following: WFMT inspection of 100% of all internal butt welds within the first three years of service WFMT re-inspection within 2 years if significant defects are found Subsequent to no significant defects being found, any subsequent inspection should include WFMT of all Tee junctions and 10% of the total length of butt welds In no case should the subsequent examination interval exceed 6 years.It is apparent from the above that latitude can exist for in-service inspection techniques and frequencies. Each owner should determine inspection frequency in conjunction with the appropriate authority. Some jurisdictions require a 3-year inspection frequency.SUMMARYThe use of carbon steel pressure vessels for storage of anhydrous ammonia in the pulp and paper industry could be a non-event or deteriorate into a cycle of inspection and repair. This article has highlighted major concerns related to SCC. There is a wealth of additional information available on all considerations related to these vessels from the ANSI and British Codes, the NACE document, ammonia suppliers, and the current technical literature. The American Institute of Chemical Engineers (AIChE) holds the annual AIChE Ammonia Safety Symposium aimed at finding ways to safely manufacture, transport, and store ammonia and related chemicals. The proceedings of these symposia are published by AIChE. It is recommended that any owner of such vessels keep aware of current expertise.Reid is materials and corrosion section head with MacMillan Bloedel Research, 4225 Kincaid St., Burnaby, BC, Canada V5G 4P5.Task group members: Craig Reid; R.S. Charlton, Levelton Associates Consulting Engrs.; R.C. Faloon, MQSInspections