矿用通风机变频控制系统设计与研究

目前煤矿通风机的控制方式多采用恒转速控制,无法根据实际需求对风机功率及输出风量进行实时调节,造成较大的电能损耗,不利于煤矿经济性及智能化发展。基于此,结合变频控制及传感器技术设计一套基于PLC的矿用通风机变频节能控制系统,实现了风机软启动及输出风量自适应调节,同时系统可对风机的风压、风量等运行参数进行实时监测,有效提高煤矿通风机的智能化运行水平。     

变频调速技术在主要通风机中的应用

通过选用变频器对通风机进行改造,将风机调整到最佳状态,通过自动化控制风机转速达到调节风量的目的,既大大简化了调节风量的额工作量,又降低了电能消耗。     

YQR-200B型燃油燃烧器配风研究

针对当前燃油燃烧器配风合理控制等问题，提出了使用一个调风板或不使用调风板直接由风机控制通风总量，各部分风量由结构保证的设计方法。分析结果表明，该方法使得配风量控制简单化，实现了合理配风。     

信息

国内首台大型机械液压动叶可调式矿井风机问世国内第一台大型机械液压动叶可调式矿井风机日前在上海鼓风机厂有限公司问世。该风机的叶片角度调节幅度达到140°,叶轮直径375m,最大风量440m3/s。目前该风机已经运往淮南潘一矿使用。上鼓公司生产制造的大型矿井风机在此之前的设计,是要让风机停车后,通过机械调节叶片,然后启动风机,实现返风功能。这一次设计的是风机不用停车,一边运行一边通过液压机构调节叶片角度,从而在风机连续运行中实现返风功能,达到了“速度保安全”的目标。(摘自《设备工程信息》)国内最大乙烯生产装置投产世界上单线…     

基于PLC的矿井通风节能控制系统的设计

文中介绍了矿井通风节能控制系统的工作原理、硬件结构组成及风机控制部分的软件流程。以瓦斯浓度为主控参数,根据风速、风量的变化,通过PLC控制变频器来调节风机转速,使之实现最优控制,达到安全监控与节能目的。该系统实现了分布式大规模节点通风参数的实时检测,系统结构简单、操作灵活,能很好地满足矿井安全生产的需要。     

空调新风系统多翼离心风机叶轮进出口角对风量影响的研究

叶轮是多翼离心风机的核心部件，探究叶轮进出口角对叶轮气动特性的影响，对空调新风系统多翼离心风机的设计及风量优化具有重要意义。针对某型空调新风系统，构建了多翼离心风机CFD整机仿真模型。在此基础上，分析了前向叶轮进出口角对多翼离心风机风量的影响，并通过数值仿真分析，对不同叶轮进出口角时的风机内部流场展开分析，最后得出优化后的叶轮进出口角方案。结果表明，当叶轮进口角为50°，出口角为169°时，风机流道流动情况得到明显优化，叶道堵塞情况得到改善，叶轮有效通流面积增大，叶轮出口气流速度提升，风机效率有所提升，风机蜗壳出口处风速均匀性较好，空调新风系统性能显著提升，蜗壳出口处风量提高1.29m3/h，增幅约1.27%。     

以先进工艺促进生产节约

国内第一台大型机械液压动叶可调式矿井风机日前在上海鼓风机厂有限公司问世。该风机的叶片角度调节幅度达到140°，叶轮直径375m，最大风量440m^3/s。目前该风机已经运往淮南潘一矿使用。     

煤矿通风机变频调速监控系统的研制与应用

应用FX2N-32M PLC和FRENIC5000变频器,以风量为主要测量参数,通过调节PID参数控制变频器频率,来改变风机电动机转速,实现最优控制.通过监测风机运行过程中的各种参数保证风机安全运行.应用表明,通过变频器调节风机转速,能有效地节约电能,是矿井通风机的一种理想控制方式.     

变频技术在主风机上的应用

通过把变频器的频率给定端子与电控系统PLC的模拟量输出端子连接，实现了主风机风量随提升机主电机定子温度的变化而自动调节，大幅度提高了风机利用率。     

风机和水泵类通用机械的节能技术

风机泵类机械在工农业生产活动中实效巩固地位极为深刻，其结构整体运行过程中会耗费大量电力能源，约占全国实际用量的四成左右，此类机械主要利用挡风板或者阀门进行风量、流量调节控制，其中的节流功率损耗同样不可小觑。所以，在机理调节过程中关于风量和流量节约措施，将对工业生态化建设和可持续发展作用产生必要辅助效应。本文主要结合机械运作实践检验操作和电动机调速功能实现节能技术开发，同时设计某种简易格式的调压调速装置。经过相关试验结果验证，整体节能效果控制比较卓越，具备批量应用的实效价值和开发潜力。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.