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近年来,随着我国城镇化进程的发展,大型城市的人口总量不断激增,导致配套的市政污水处理厂的建设规模也随之扩大。然而对于寸土寸金的大型城市而言,土地资源十分紧张,地下式污水处理厂应运而生。相比常规的污水处理厂,地下式污水处理厂配套的自动化控制系统更加复杂。本文以虹桥污水处理厂的自动化控制系统设计为例,简单介绍污水处理厂自动化控制系统的配置和各个处理单体按功能需求的仪表配置情况。 相似文献
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城市污水处理系统是城市系统中的重要组成部分,随着我国科技的不断发展进步,我国污水处理系统也逐渐地向着智能化、自动化的方向发展,PLC作为一种先进的技术,在污水泵站自动化控制系统中有着广泛的应用.PLC在污水泵站自动控制系统中的应用,实现了泵站自动化控制,报站系统的安全、稳定运行.本文主要对PLC概述及特点分析,对污水泵... 相似文献
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我国大城市工业污水排放点多、分布广,监测困难,为此设计一套基于GPRS的分布式无线污水排放监测系统.该系统不受复杂环境、气候等诸多因素影响,可实现对城市工业污水排放的信息采集、传输和处理自动化. 相似文献
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《仪表技术与传感器》2021,(3)
为解决当前污水泵站自动化程度低、无法远程监控的难题,设计了一套基于工业物联网的远程监控系统,对污水泵站自动化系统进行改造。该系统上位机采用微信小程序二次开发监控软件,下位机采用STM32控制器,现场设备由各种仪表和执行设备组成;通过工业以太网,控制器把现场监控数据传到云服务器,微信小程序监控软件与云服务器相连,从而实现了污水泵站的远程监控。改造后试运行结果表明,系统反应灵敏、运行稳定、能实时远程监控污水泵站运行状况。 相似文献
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为了降低较为昂贵的镜面抛光和光机装配费用,以及应对温度、重力及其他意外因素导致的镜面低阶像差,一种在被动浮动支撑结构上施加力矩以实现面型实时校正的力矩促动器在部分望远镜上已有成熟应用。本文旨在针对我国未来的大口径地基光学望远镜,对其拼接子镜力矩促动器的分布进行优化与设计。首先根据工程经验和参考文献初步确定力矩促动器所需校正能力,通过三维建模软件对拼接子镜及镜室进行建模,最后通过有限元仿真和最小二乘法拟合对力矩促动器的布局进行优化设计。计算结果表明,采用18个力矩促动器的分布方案能够对离焦、像散、彗差、三叶像差进行良好的校正。对于具有数百面子镜的拼接望远镜来说,18个力矩促动器的方案在满足光学设计需求的同时,有效节约了建设经费并降低了工艺的复杂性。 相似文献
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分析了链传动在实际运转过程中,紧边链条与链轮上不同圆相切的情况,从这一角度出发,当中心距和链节数以链条松、紧边与2链轮分度圆相切为条件确定后,链条紧边与链轮不同的圆相切将导致松边垂度和张力变化。 相似文献
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An approximate analytical approach to the torsion of thin-walled beams of open cross-section with influence of shear is presented. It is assumed that the normal stresses in the cross-section contour direction are small compared to the normal stresses in the beam longitudinal direction that can be ignored in the stress–strain relations. The stresses and displacements are obtained in the closed analytical form. It is assumed that transverse load can be reduced to moments of torsion only, with respect to the cross-section shear centre. The beam will be subjected to torsion, with respect to the shear centre, i.e. the principal cross-section sectorial coordinate, in the case of cross-sections with two axes of symmetry; to torsion and bending in the case of cross-sections with one axes of symmetry and to torsion, bending and tension in the case of general cross-sections. An illustrative example of beam with one axis of symmetry is given. 相似文献
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In a recent paper, the Ritz method with simple algebraic polynomials as trial functions was used to obtain an eigenvalue equation for the free vibration of a class of homogeneous solids with cavities. The method presented is here extended to the study of a class of non-homogeneous solids, in which each solid is composed of a number of isotropic layers with different material properties. The Cartesian coordinate system is used to describe the geometry of the solid which is modelled by means of a segment bounded by the yz, zx and xy orthogonal coordinate planes and by two curved surfaces which are defined by fairly general polynomial expressions in the coordinates x, y and z. The surface representing the interface between two material layers in the solid is also described by a polynomial expression in the coordinates x, y and z. In order to demonstrate the accuracy of the approach, natural frequencies are given for both a two- and three-layered spherical shell and for a homogeneous hollow cylinder, as computed using the present approach, and are compared with those obtained using an exact solution. Results are then given for a number of two- and three-layered cylinders and, to demonstrate the versatility of the approach, natural frequencies are given for a five-layered cantilevered beam with a central circular hole as well as for a number of composite solids of more general shape. 相似文献
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根据液压旋耕机的工况特点,基于定流量阀后补偿负载敏感原理设计液压旋耕机的工作系统,分析该系统工作原理,采用AMESim平台搭建该工作装置负载敏感系统仿真模型,仿真分析该系统分别处于变负载工况、多路阀不同开口工况与流量饱和工况下的工作特性。由仿真可知,该负载敏感系统各执行机构所需流量主要取决于多路阀开口面积,与负载无关。且当系统发生流量饱和时,会根据多路阀前后压差按比例分配定量泵输出流量,使各执行机构独立地工作。证实了将负载敏感系统运用在旋耕机中,使旋耕机能够实现单泵驱动多个动作,实现升降液压缸与回转液压马达的复合动作,使其工作系统便于控制。 相似文献
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