Experimental research of overburden movement and subsurface water seeping in shallow seam mining

Shallow seam coal field has the largest coal reserve in China. Mining in shallow depth causes serious problems, and sub- surface dewatering is a major issue. In this paper, the physical simulating models were prepared to study overburden movement and aquiclude stability in the shallow seam mining of Yushuwan Coalfield, China. According to the characteristic of clay aquiclude and bedrock in the overburden, the proper simulation materials for simulating the plastic clay aquiclude layers and brittle bedrock layers were determined by the stress-strain tests and hydrophilic tests. The physical simulating models of solid medium and two phases of solid-liquid medium were carried out to simulate the failure and caving process of the roof and overburden, as well as the subsurface water seeping. Based on the simulation, it was found that the movement of clay aquiclude follows the movement of the underlying bedrock layers. The stability of aquiclude is mainly affected by cracks in fracture zone. The tests also showed that the best way to control the stability of aquiclude is to reduce the subsiding gradient, and there is a possibility of ground water conservation under longwall mining in Yushuwan Mine. This research provides a foundation for further study on mining dewatering and water conserva- tion.     

橡胶履带质量问题的原因分析及解决措施

分析橡胶履带裂口、气泡、钢丝帘线断裂的产生原因,并提出相应的解决措施。采用严格控制炼胶、成型、硫化等工艺条件,改进工艺操作,严格执行施工标准,优化部件和产品结构以及胶料配方,规范产品装配和使用等措施,可有效解决橡胶履带裂口、气泡和钢丝帘线断裂问题。     

全钢载重子午线轮胎装配线裂口和胎圈脱空原因分析及解决措施

分析全钢载重子午线轮胎装配线裂口和胎圈脱空的原因，并采取相应解决措施。通过胎侧胶与耐磨胶搭接面厚度增大0．5～1．0mm，胎圈包布外端点胶片粘贴方式由包边改为搭接，上下三角胶端点高度提高5～8mm，胎体帘布和钢丝圈包布外端点高度提高2～3mm，胎体帘布外端点处三角胶厚度增大1mm，缩小钢丝圈直径；降低胶片挤出温度，在钢丝压延辊增设划气泡装置，成型时采用激光灯标定位等措施，基本解决了轮胎装配线裂口和胎圈脱空问题。     

轮胎硫化胶囊使用过程中质量缺陷分析与判定

简要介绍轮胎硫化胶囊选型、使用安装过程注意事项,用胶囊使用中出现的质量问题缺陷、意外损坏等现象,以图片记录方式,展现胶囊的一些常见缺陷问题、损伤等,便于胶囊管理相关人员的鉴别和确认     

铝箔裂口产生原因的分析

轧制过程中铝箔如出现较大裂口，会使生产中频繁断带，也影响使用质量、裂口已成为铝箔的主要缺陷。分析了铝箔产生裂口的原因，提出了预防措施，从而使铝箔裂口废吕率明显下降。     

自动跨越轨底焊瘤和缝隙的刮胶垫装置

在大修铁路无缝线路回收旧长钢轨时，为便于施工，需提前将钢轨截断后再用鱼尾板连接成整体，然后用机车推着平板车及引轨小车，把钢轨收到平板车上。引轨小车如图1所示，由于钢轨底部的胶垫受灰尘、油污的侵蚀和长年频繁挤压，紧贴在钢轨底部，大量的旧胶垫在收轨滚轮反复滚压下掉落，将平板车上的滚轮挤死，影响正常收轨作业。因此，需经人力用铁锨等工具在收轨作业过程中铲除胶垫，既费工又不安全，旧胶垫也不便于回收。     

斜交轮胎胎侧缺胶和裂口的原因分析及改进措施

斜交轮胎胎侧缺胶和裂口的原因分析及改进措施胡付存（山东曹州橡胶厂２７４４００）为适应市场需求,我厂在进行轮胎结构调整的同时,对斜交轮胎个体硫化机进行了部分改造：将原来的专一性较强的汽室式加热法硫化,改造成适于多规格轮胎模具的热板式加热法硫化,从而装模...     

6.50R16 8PR轻载子午线轮胎胎圈裂口问题的解决措施

造成６．５０Ｒ１６８ＰＲ轻载子午线轮胎胎圈裂口的主要原因是轮胎结构设计不合理和使用不当。从结构设计上,应增大轮辋宽度及调整上下胎侧曲线等;从施工设计上,采用上下复合三角胶及用２层尼龙加强层替代原一层钢丝加强层等;从工艺设计上,调整成型工艺参数并相应调整成型压力参数等。改进后进行了成品试验。试验结果表明,改进后轮胎外缘尺寸符合国标,耐久性能提高１７０％,行驶里程延长１倍左右。     

旋转压缩机冰箱噪声问题

介绍了旋转压缩机冰箱胶垫碳化引致噪声增大问题的有效解决方法