两柱掩护式电液放顶煤液压支架设计

针对四柱放顶煤支架在开采过程中出现拔后柱、支护效率低等情况,研究设计两柱掩护式电液放顶煤液压支架。通过优化支架四连杆机构,改善支架整体受力状况,提高支架支护效率;优化顶梁立柱支撑位置,扩展支架合力作用点的分布范围,防止支架放煤前后的"高射炮"和低头;同时支架采用整体顶梁,提高支架前端支顶力,防止片帮、冒顶,更好维护顶板。     

大工作阻力放顶煤液压支架顶梁后部结构优化设计

为探究工作阻力在18 000 kN以上的四柱放顶煤液压支架顶梁后柱窝后部结构形式与顶梁后柱窝点到顶掩铰接孔距离的关系,分析了顶梁后柱窝所受弯矩与顶梁后柱窝点到顶掩铰接点距离的关系。根据后柱窝点到顶掩铰接点距离大小,从结构设计角度,将顶梁后柱窝后部结构归纳整理为全箱形结构、半箱形结构及无箱形结构。针对每种结构,经有限元分析、局部参数优化及适用性分析后,给出具体应用案例,为大工作阻力放顶煤液压支架顶梁后部的结构设计提供参考,为提高液压支架的使用寿命及可靠性提供支持。     

大采高综放工作面煤壁片帮与顶煤冒放性影响分析

针对塔山煤矿大采高综放工作面煤壁片帮防治难题,采用理论分析、数值模拟与现场实测相结合的方法,分析了相同机采高度情况下大采高综放工作面煤壁片帮较大采高综采工作面煤壁片帮剧烈的原因,揭示了综放工作面抑制煤壁片帮与提高顶煤冒放性之间的矛盾,研究了液压支架结构参数对煤壁片帮的影响。研究结果表明:由于受塑性破坏区叠加及顶煤冒落放出的影响,相同机采高度情况下,大采高综放工作面煤壁片帮比大采高综采工作面更加剧烈;合理的液压支架初撑力可在缓解煤壁片帮的同时提高顶煤冒放性;整体顶梁比铰接顶梁更有利于抑制煤壁片帮,同时可以通过适当增大液压支架顶梁长度来缓解煤壁片帮与顶煤冒放性的矛盾;护帮板与伸缩梁分体结构作为大采高综放液压支架一种新的护帮结构形式,比护帮板与伸缩梁连体结构更有利于抑制煤壁片帮。     

兖州矿区综机设备发展趋势

最近，兖州矿业(集团)公司研究了兖州矿区综机设备的发展趋势。其主要内容包括：1)液压支架。放顶煤支架采用反四连杆形式，把四连杆机构放在两立柱间，以增大后部放煤空间；采用大尾梁、大插板形式，尾梁直接与顶梁铰接，使顶煤的受控排放能力大为增强；采用整体顶梁带伸缩前梁的结构，以提高支架前端的承载能力，防止工作面冒顶；提高支架整体可靠性、结构件强度及焊接质量，研制高性能密封件和液压元件；采用由先导回路控制的大流量系统，使移架速度控制在10s以内。分层开采则向两柱掩护式支架发展，因其具有工作高度调节范围大、     

放顶煤液压支架应用和选型趋势研究

综采放顶煤开采以来,虽然应用四柱放顶煤液压支架比较普遍,但是该架型前、后柱受力不均,有效支护效率低是造成工作面顶煤及顶板出现片帮冒顶的主要原因。近十年的发展和应用研究表明,两柱放顶煤液压支架不仅技术成熟且优越性突出,已经被大量推广应用。要针对煤层开采条件和配套设备特点进行个性化配套选型和液压支架设计,防止重大技术问题和事故的发生。     

适用于小罐笼运输的液压支架顶梁结构及其优化设计

为解决工作阻力在13 000 kN以上液压支架顶梁无法满足小罐笼运输要求问题,通过液压支架整体受力分析,从满足液压支架适应性角度,将顶梁结构分为插楔子形顶梁结构及铰接顶梁结构,对插楔子形顶梁的联接箱强度及数量、铰接轴规格等进行改进及优化设计,通过液压支架整架及顶梁整体有限元分析验证,表明插楔子形顶梁可以满足液压支架井下的使用要求,为利用罐笼运输设备的矿井由于无法适用于目前为提高产能而配套的大功率、大尺寸设备的罐笼运输问题提供了一种解决方法。     

不同结构形式顶梁对顶板支护性能的影响分析

针对煤矿井下液压支架的使用状况,讨论了整体顶梁与铰接顶梁对顶板前端支护性能的影响,并以某一型号液压支架为例,阐述了整体顶梁与铰接顶梁前端力的差别,对液压支架顶梁结构形式的选择及设计具有一定的借鉴意义。     

一种防滑金属铰接顶梁

提高支架整体抗推能力 ,是工作面防推垮型冒顶的主要手段。文章介绍了一种防滑铰接顶梁 ,从提高铰接顶梁与顶板的接合性和摩擦力的角度 ,来增强支架整体抗推能力 ,并介绍了防滑铰接顶梁的结构和现场应用效果。     

“三软”煤层放顶煤排头液压支架前梁的设计

针对"三软"煤层的特点,分析了放顶煤排头液压支架前梁设计中需解决的架前冒顶和煤壁片帮问题,从提高前梁端部的支撑能力和接顶性能、采用前后铰接式顶梁、铰接可伸缩式前梁等方面,改进前梁的结构设计,并进行强度校核,验证了设计的正确性和可靠性。     

机采高度对顶煤冒放性与煤壁片帮的影响

针对特厚煤层大采高综放开采顶煤冒放性与煤壁片帮难题,采用理论分析、数值模拟及技术经济综合对比分析等方法,分析了工作面机采高度对煤炭资源回采率及煤壁片帮的影响。通过建立特厚煤层大采高综放工作面煤壁片帮的压剪力学模型,分析了大采高综放工作面煤壁片帮机理,研究了相同机采高度情况下大采高综放工作面较大采高综采工作面煤壁片帮更加剧烈的原因。增加液压支架对顶煤的主动支护作用力及选择合理的液压支架架型结构参数,既可以提高顶煤的冒放性,同时还可以降低煤壁的片帮概率。综合分析不同机采高度对煤炭资源回采率、煤壁片帮控制及工程与设备投资的影响,确定罐子沟煤矿大采高综放工作面机采高度为4.5 m,设计研发的ZFY12000/26/47型两柱掩护式整体顶梁大采高综放液压支架使用效果较好。     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

唐口煤矿深部复杂开采工作面瓦斯分源涌出规律研究

研究工作面瓦斯涌出规律对工作面瓦斯治理有重要意义。为了得到唐口煤矿深部3号煤层复杂开采条件下工作面回采时期瓦斯涌出时空演化规律,选取6304工作面作为对象,采用实测方法研究6304工作面瓦斯涌出规律。结果表明:6304工作面瓦斯涌出量为6.534 m³/min,其中煤壁占34.27%,落煤占29.62%,采空区占36.11%;沿工作面倾向由低到高,瓦斯浓度整体为上升趋势,其中1—76号架工作面瓦斯浓度小于0.20%,76—102号架瓦斯浓度上升明显,最大为0.387%;上隅角的后部采空区是工作面的瓦斯主要涌出源,上隅角1号测点瓦斯浓度0.78%,上隅角周边3号、5号、7号、8号、9号测点瓦斯浓度平均为0.643%;周期来压时,上隅角瓦斯相对平时较高。研究为针对性的瓦斯分源监控与灾害防治提供基础。