高压旁路调节阀工作原理研究及运动分析

国内大型火电厂汽轮机主蒸汽系统高压旁路调节阀主要依赖进口,国内阀门厂家在该领域没有成熟的设计计算方法和生产制造技术。本文从高压旁路调节阀结构特点和工作原理研究入手,结合超临界、超超临界机组高旁阀温度高、压力高的工况特点,研究分析可能影响阀门工作性能和可靠性的阀笼、阀芯、阀座、预启阀、碟簧等主要零件的受力情况,并根据阀内零件力平衡机理,建立各相关零件受力计算数学模型,为高温高压调节阀的设计提供一种受力分析计算的方法。     

煤化工专用黑水阀阀座流通性能研究

介绍了一种煤化工专用黑水阀的结构构成,并提出进行该型号阀门流通性能研究的重要性。建立流道三维模型,应用CFD有限元分析软件,模拟黑水阀内部流场分布情况,分析可视化结果,确定阀座/阀芯易损位置。分别对不同阀座渐扩角时模型进行仿真模拟,得到阀门进、出口压力值,并依此计算Cv值大小,拟合流量系数曲线,提出阀门在实现最大介质流通时阀座渐扩角范围,为阀门设计提供重要的理论参考。     

阀门密封面堆焊质量控制的常见问题与建议

阀门是工业生产中重要的配件,在各个领域有着广泛应用,对于生产安全有着极大的影响。在阀门焊接中,密封面的堆焊是最为常见的,是通过在阀门密封面部位堆焊一层特殊性能合金,来提高阀门密封面的抗高温,抗冲蚀等多种性能。目前阀门封面堆焊的质量问题成为大家研究的重点,阀门的问题与其安全性、密封性、使用时间息息相关。因此对阀门密封面堆焊质量的控制显得十分重要,了解阀门密封面堆焊质量出现的问题,才能更好的解决问题。接下来对阀门密封面堆焊质量控制的常见问题进行分析,对出现的问题提出一些可靠的建议。     

M701F型联合循环机组的汽轮机旁路控制系统探讨

在分析M701F型联合循环机组控制问题的基础上,对机组的汽轮机旁路控制系统展开了分析,以掌握系统的结构、控制模式和高、中、低压旁路控制方式。     

液压支架平衡千斤顶控制回路优化设计

分析了采用补偿阀、高压内溢流式阀、浮动双向锁、自动平衡阀等控制液压支架平衡千斤顶的原理及不足,根据平衡千斤顶容腔压力特点,提出了一种液压支架平衡千斤顶控制回路优化设计方案。通过合理配置液控换向阀、低压卸荷阀等元件位置,可实现平衡千斤顶容腔的自动补液与卸荷,解决安全阀非紧急情况下频繁开启的问题。仿真和试验结果验证了该优化设计方案的有效性。     

大庆石化公司5#机高压调节阀故障分析及改进

汽轮发电机组通过控制汽轮机进汽阀门的开度来调节进汽流量,从而达到控制汽轮发电机组转速和功率的目的.造成汽轮机高压调节阀窜动的的主要原因是调节阀LVDT部套因接线松动、振动、瞬间接地等导致阀门位置反馈信号不稳定或失真,进而引起PID控制回路的控制输出指令与阀位负反馈信号无法平衡,使阀门出现震荡现象.采取相应措施对高压调节阀进行改造,使得机组运行安全性得到了较大的提高.     

自制耐强腐蚀的气动阀

化工自动化离不开气动薄膜调节阀,因为它不但是控制参数的直接操纵者,而且气动阀可靠性高,适应恶劣环境的影响。然而目前我国耐强腐蚀介质的调节阀无论是品种和数量都几乎空白。我厂生产的98%以上的浓硝酸是一种强腐蚀剂。为了解决强酸生产的控制问题,我们用en654钢手动阀改制成气动单座调节阀。改制方便,使用可靠。该调节阀的阀座利用手动阀的阀座,材质en654钢(该手动阀至今还没有生产,为某厂特例加工),阀芯     

660MW机组冷态启动中转速控制异常原因分析

本文描述了660MW超超临界机组某次冷态启动阶段,汽轮机TV—GV阀切换过程中发生转速波动并导致OPC动作、TV不受控等异常现象。通过对热工TV阀控制逻辑SDTV—GV阀切换具体逻辑,剖析汽轮机伺服系统故障引起阀门卡涩、阀门实际位置和受力差等可能导致TV阀失控的原因分析,查明导致汽轮机转速异常波动以及TV阀不受控的原因予以消除,并就防范机组类似安全隐患,提出建议供同行参考。     

冲击环境下航天器电磁自锁阀锁闭特性研究

电磁自锁阀广泛应用于卫星、运载火箭、飞船等航天器中,在发动机点火、火工装置爆炸、星箭分离等强冲击环境下,可能发生锁闭失效,影响航天器的安全运行.本文针对冲击载荷作用下电磁自锁阀的锁闭可靠性问题,研究了自锁阀锁闭失效机理,建立了工装-自锁阀有限元模型,并通过模态试验验证模型的正确性.基于模态叠加理论,研究自锁阀的冲击响应特性,根据冲击响应结果和阀芯能量分析,判断阀芯锁闭状态.为了验证分析结果的准确性,使用摆锤式冲击台开展冲击试验,得到的阀芯锁闭状态与理论分析结果吻合良好,说明了分析方法的有效性.本文的研究可为电磁式自锁阀的抗冲击设计提供理论基础和技术支撑.     

“电磁阀”讲座：第三讲 阀孔密封

电磁阀通常是二位动作的通断型阀门,属闭路阀的一类产品。由于,阀内漏是表征阀性能的一项主要指标,因此,阀孔密封是该产品的技术关键之一。众所周知,电磁阀为了保持其轻小简廉的特色,要求尽量减小它动作所需的电磁力。据介绍,电磁力不应超过245N。但从现有产品样本所见,它的电磁力很少超过98N,因此密封力也应尽量小,应远小于70N。于是,密封力与克服内漏成了电磁阀技术中的矛盾,处理好这对矛盾,是电磁阀的技术基础与关键。     

Polymer micro valve with a hydraulic piezo-drive fabricated by the AMANDA process

A normally-closed piezo-driven micro valve for gases and liquids has been developed. Due to the small deflection of piezo-actuated bending disks made of PZT a hydraulic transmission was constructed, which increases the displacement of the piezo disk up to the 25-fold. The switching times of the valve are shorter than 1.8 ms.

Silicone gel serves as a transition medium in the hydraulic. It simplifies the manufacturing process and allows a flexible adaptation to different pressure requirements up to a differential pressure of 150 kPa switched with 300 V. Additionally, this silicone gel supports the sealing of the valve so it achieves an open-to-close ratio of 1:150,000 or higher.

The overall dimensions of the valve are 13 mm×13 mm×3 mm, the dead volume is 0.33 μl, and the inner diameter of the valve seat is 200 μm. A transformer as small as the micro valve is able to produce driving voltages of up to 300 V with a response time of 2 ms. Therefore, the valve could be integrated into hand-held systems which are battery powered with 5–15 V.     

基于Abaqus的喷油器孔板密封性分析

以某款喷油器为研究对象,基于Abaqus对其密封性进行计算分析,结果表明其密封性薄弱部位为孔板密封面.通过增大控制阀座拧紧力矩和改进孔板结构2种方式,提高电控高压喷油器孔板接触面的密封性能.     

Optimal design of metal seated ball valve mechanism

A seat is a device mounted in a valve. When a ball valve is in the closed position, the seat seals the ball valve. The seat is usually made from plastic or rubber, so it can be damaged by high pressure or high temperature environments. The objective of this study is to design a new metal seat mechanism for the ball valve. To design a new metal seat, there are four steps to the engineering design process: planning and clarifying the task; conceptual design; embodiment design; detailed design. Some useful tools from the Quality Function Deployment (QFD) technique and the Theory of Inventive Problem Solving (TRIZ) method are used in this design process. The design optimization is completed by the ANSYS package. The novel design of the metal-seated ball valve provides low torque, low wear and long life.     

高温冲击下三偏心蝶阀的密封性能

某三偏心金属蝶阀在工作中承受瞬时高温、高压冲击,为探索该环境工况对蝶阀密封性能的影响,采用Ansys软件对蝶阀进行热-结构间接耦合分析,研究高温、高压冲击下蝶阀的变形、应力分布和密封特性.蝶阀的温度分布结果表明瞬间的高温仅造成蝶阀温度升高0.23 K,而3.0 MPa的冲击可使得阀门密封面之间的接触应力平均增大60.0 MPa.密封比压的增大表明阀门在冲击下密封情况良好,分析结果可为特殊工况条件下三偏心蝶阀的选型与改进提供指导.     

Passive MEMS Valves With Preset Operating Pressures for Microgas Analyzer

In this paper, we present integrated disk-in-cage poppet valves with tuned spring stiffness for gas flow control of a microgas analyzer. The valves require zero power and close at preset offset pressures (0–35 psig) to switch from gas sample loading onto a preconcentrator to concentrated constituent sample injection into a microgas chromatograph. Air flow rates of 4.5 mL/min at pressures of $-$ 2.5–$-$5 psig (vacuum sample loading) were measured. Hydrogen leak rates of 0.1 $muhbox{L}/hbox{s}$ (0.006 mL/min) were measured with valves closed at 15 psig. Analytical and numerical modeling was used to guide design of valve spring constants (ranging from 10 to 1500 N/m) that control the valve open position, flow rate, and closing pressure. The parameter design space is limited to a range of seat overlap, valve size, and spring stiffness that will allow adequate flow rate, sealing, and closing at predictable pressures. A linear curve defining closing pressure as a function of spring constant, valve gap, valve size, and seat overlap fit measured closing pressure data and can be used to predict closing pressure for future designs. $hfill$ [2008-0002]      

某660MW超临界机组给水泵汽轮机调节系统故障分析及处理

某660MW超临界机组给水泵汽轮机在试运中,出现挂闸失败、调节油压低、速关阀不能正常开启、跳闸等问题,延误机组启动时间,严重影响机组和电网的安全运行。本文结合给水泵汽轮机调节系统油路流程和工作原理,分析出现挂闸失败、调节油压低等问题的原因,总结出该类型调节系统的故障特征,提出解决思路和处理方法,并通过现场试验,验证了处理方法的正确性,为快速判断和处理该类型调节系统类似故障提供依据;同时结合给水泵汽轮机速关阀结构原理,推导出速关阀中活动部件的力平衡方程,分析了速关阀动作过程对给水泵汽轮机挂闸的影响及其不能正常开启的原因,并从速关组件的结构原理出发,结合速关阀挂闸时的动作过程,推导出给水泵汽轮机挂闸成功与否启动油压力下降速度相差大的原因,为准确分析跳闸提供依据。     

海洋机器人用水下电机的深水密封研究

本文研究了海洋机器人用水下电机各个部分的密封方法，同时介绍了一个先进的动密封装置以及检验密封性能的水压试验方法．经测试及实际使用表明该密封方法和动密封装置完全满足水下机器人在深水中运行的密封要求     

A microvalve for lab-on-a-chip applications based on electrochemically actuated SU8 cantilevers

Increasing the complexity and functionality of Lab-on-a-Chip devices requires integrated valves for internal flow regulation. The device introduced in this work is an electrochemical SU8 microvalve, featuring a cantilevered structure that seals an adjacent channel under the action of a growing electrolysis bubble. The valve is based on previously reported movable microcantilevers embedded in microchannels. As opposed to membrane valves moving perpendicular to the substrate, the cantilever valve is patterned next to the channel and closes it by moving horizontally, dramatically reducing footprint. Its compact, monolithic and 2D construction reduces assembly problems and results in negligible increase in dead volume (14.5 nl). Besides, its location in the way of the channels avoids the need for auxiliary filling ports or separate working media for actuation. Effective sealing with negligible leakage at 20 kPa has been achieved. The valve also displays passive flow regulation induced by the pressure differential generated across the valve chamber under flow conditions (42-72% flow decrease).     

Analysis of fluid flow and deflection for pressure-balanced MEMS diaphragm valves

Based on the linear plate theory for an elastic thin plate and the Bernoulli equation for a steady incompressible and inviscid fluid flow, the effect of fluid flow on the deformation of microelectromechanical systems (MEMS) diaphragm valve is investigated both analytically and numerically. For a given configuration of diaphragm valve, a relationship between the applied pressure and resulting contact area between diaphragm and valve seat is derived. Possible instability of such a system under the pressure-balanced mechanism is demonstrated with both analytical and numerical solutions for the deflection. Deflection as a function of flow speed, radius of outlet orifice, inlet gap, and bending stiffness of diaphragm are presented. In addition, the effect of diaphragm making contact with the valve seat due to pressure differential and fluid flow is analyzed and a relation between the contact zone and the external pressure is obtained. The results of the analysis suggest important parameters in the design of MEMS diaphragm valves and can be used as a basis in the design of such valves.