带式输送机的液力软启动

带式输送机在启动的过程中避免不了会出现一些严重的问题,如输送带受损、满载启动、紧急停车、低速验带等.福伊特阀控调速型液力耦合器能够很好地解决以上问题,从而实现"软启动".本文介绍了带式输送机的液力软启动,福伊特阀控调速型液力耦合器的结构及原理,与使用它进行液力软启动,解决启动过程中出现问题的方式及效果.     

专用压力机的设计

本文按实际要求对专用压力机的传动进行了论证,选择,设计和计算,画出了液压系统图和电气系统图,并且分析了这种压力机性能的优劣和技术的先进性。     

汽车起重机回转机构液压系统动态仿真

从研究汽车起重机回转机构液压系统入手 ,利用计算机数字仿真方法分析其动态过程 ,对影响回转机构液压系统动态特性的主要因素进行了讨论 ,为回转机构液压系统的设计提供了理论依据     

Research on the methods of detecting and removing slide valve failure

Various ways for detecting slide valve failure are discussed in the paper. Specifically, a new method for detecting slide valve sticking state is first presented. The method does not depend on any special sensor and is only based on the detection of oscillation current wave within a valve coil. Results of theoretical analysis and experimental research are given for comparison. In order to remove a slide valve sticking online, a concept and method of “electrical hammer” is introduced. At last, an application example of the methods is discussed. In fact, it is an electro-hydraulic turbine system with failure diagnosis, fault-tolerant and trouble removal functions. Project (59775003) supported by NSFC     

液压传动系统在塔式起重机顶升系统中的应用

本文阐述了塔式起重机顶升装置所采用的液压传动系统的组成、各液压元件的功能以及工作原理,并概述了液压系统的使用、维修及常见故障的处理方法。     

液体压强教学实践点滴

讨论了液体压强教学实践中的若干问题．     

Effects of Shallow Groundwater Table on Soil Matric Potential and Hydraulic Characteristics

Groundwater recharge significantly affects soil moisture redistribution through capillary rise. In this study,the soil matric potential at depths of 5, 10, 20 and 30 cm above the groundwater tables of 10, 30 and 60 cm were measured for 5 d. Soil hydraulic properties were analyzed by using the Philips and de Vries model. Results showed that evaporation mainly influenced the matric potential of the shallow layer at the 5 cm depth regardless of the saturation of the layer. Groundwater recharge mainly affected soil moisture at the depth of 20 cm or more. A constant matric potential layer existed between the evaporation front and capillary rise front where moisture content did not change.The isothermal-liquid hydraulic conductivity(KLh) and the thermal-vapor hydraulic conductivity(Kv T) were the dominant hydraulic conductivities in the liquid and vapor phases. At the groundwater table depths of 10, 30 and 60 cm,the mean peak values of KLh were 2.32×10-7, 1.63×10-7 and 0.29×10-7 m/s, respectively, whereas the mean peak values of K-v T were 2.7×107, 2.4×10-7 and 1.8 ×10-7m/s, respectively.     

雨水综合管理规划、评价和实施:以上海为例(英文)

提出了一套基于低影响开发理念的城市雨水综合管理规划方案.与传统排水规划不同,该方案通过在社区尺度上规划各类低影响开发设施,削减径流总量和污染负荷,实现可持续的城市雨水综合管理.采用结合了传统排水管道和低影响开发设施的水力模型,对规划效果进行了评价.通过20年降雨数据的连续模拟发现,在规划完全实施基础上,相对于不采用低影响开发设施,径流总量削减率可达80%以上.为保障和指导规划的实施,结合当地条件,制定了技术实施导则.规划区域内3条主干道道旁生物滞留设施已完成施工建设,区域内其他地块的开发也正在实施导则的指导下逐步开展和实施.提出的基于低影响开发理念的区域雨水综合管理规划、评价和实施方法,将为我国其他地区的类似项目提供经验和借鉴.     

乡村清洁拖拉机电液举升模糊控制系统设计

文章阐述了乡村清洁拖拉机电液举升控制系统工作原理,推导了被控对象举升缸传递函数,运用线性控制理论分析了举升缸系统输出可控性与可观性。从而设计了乡村清洁拖拉机电液举升模糊PID控制系统,并进行了仿真分析,对传统液压举升系统自动控制方面的研究具有指导作用。     

厚板轧机工作辊弯辊液压管路系统改造

采用设计的过渡块消除了阀台出去的管路相对集中和管路复杂、弯头、三通多的问题,便于日常点检和维护。在振动大的部位采用软管连接方式,减少整个管路的受迫振动带来的负面影响。