共查询到20条相似文献,搜索用时 406 毫秒
1.
2.
1余热电站的电动执行器配置情况
电动执行器是自动控制系统中的一个重要组成部分,它接收来自调节系统的电信号,将其转换成适当的力或力矩,以推动各类调节阀门,达到自动控制的目的。我公司余热电站电动执行器均采用AI/M1系列电动执行器,其中大阀门执行器24台,采用开关量控制锅炉废气管道,其阀门开关量信号有:开度反馈、开/关限位、开/关力矩、开/关驱动;小阀门执行器18台,为模拟量控制蒸汽、水管道上的阀门,其阀门模拟量信号有:开度反馈、开/关限位、开/关力矩、开度给定。另AI/M1系列电动执行器使用制造商提供的红外线手操器, 相似文献
3.
TDZ阀门电动装置包括TDZ直行程电动执行器,单座调节阀和控制器三部分组成。TDZ直行程电动执行器是一种小力矩电动执行机构,是工业控制系统中的理想执行单元,具有自动调节和人工调节两种方式,TDZ直行程电动执行器,控制器和单座调节阀门构成一套自动控制部件,可广泛应用于温度,压力,流量或液位的调节控制。 相似文献
4.
5.
6.
丁训禄 《化工自动化及仪表》1986,(1)
在国产卅万吨合成氨系统的脱碳工段中,设有贫液流量(G502—T)和半贫液流量(G503—T)二套调节系统。系统执行机构——气动薄膜调节阀,在工艺倒泵、开启备泵时,或调节阀关闭及小开度运行时,泵出口压力升高,造成调节阀允许压差超指标,引起调节阀及其管道极度抖动,从而发生反馈杆脱落甚至使反馈杆连接杆振断 相似文献
7.
根据原油管线运行中对压力、流量等参数的控制要求,在研究和实践的基础上,将数字PID控制器应用到对原油输送管线的控制中。PLC经过PID运算计算出控制数据,通过现场气动调节阀调节阀门开度,实现了管线运行参数的自动控制。通过现场应用,该方案能够大幅减少操作人员劳动强度,有效的保证管线按照设定参数安全平稳运行。 相似文献
8.
调节阀工作特性校正的探讨孙之达(金陵石化公司化肥厂,南京,210033)安装在工艺管线上的调节阀工作特性受到管线特性和流体性质的影响,往往会呈现非线性。这种非线性表现为调节阀增益随阀门开度而变化。这给操作带来不便,严重时会使调节系统产生剧烈振荡。使用... 相似文献
9.
TDZ阀门电动装置包括TDZ直行程电动执行器、单座调节间和控制器三部分组成。TDZ直行程电动执行器是一种小力短电动执行机构,是工业控制系统中的理想执行单元。具有自动调节和人工调节两种方式。TDZ直行程电动执行器、控制器和单座调节阀门构成一套自动控制部件,可广泛应用于温度、压力、流量或液位的调节控制。 相似文献
11.
设置pH计量程,将信息传递给调解器,再通过调解器将信息处理后反馈并控制自动阀门开度,达到自动调节pH值的目的。 相似文献
12.
13.
全启式弹簧安全阀的结构与性能分析 总被引:1,自引:0,他引:1
对全启式弹簧安全阀的结构作了分析,指出了其主要组成元件的特点,对喷嘴形阀座的结构形式作了定性分析,并指出了阀瓣与阀座组成的密封副所存在的问题,给出了研究方向。 相似文献
14.
15.
The activation of safety valves causes the development of flow reaction forces that have to be transferred in an adequate way via the piping to the steel structure or via the connected vessel into the foundation. If the safety valve outlet piping is connected to a blowdown system or, in case of blowing off into the atmosphere, are equipped with a T‐piece at the outlet, the stationary reaction forces are compensated completely. The transient opening process, however, develops flow reaction forces which culminate in peaks of short duration. In this article, a simple method will be proposed for the estimation of the resulting reaction forces as a function of the length of the pipe at the safety valve outlet. CFD calculations and blowdown tests executed with a full‐lift safety valve have confirmed this method on principle. Special importance is attributed to the short duration of the effect of the reaction forces which seems to have only a negligible impact on the supporting steel structure. 相似文献
16.
17.
针对长输油管道广泛应用的水击泄压阀,应用CFD方法对其内部流场进行了分析计算。按照实际泄压阀的结构,建立了简化后的二维流场几何模型,根据模拟的流场压力分布计算不同开度、不同开启压力和不同管径下泄压阀的阻力系数,指出泄压阀的阻力系数与开度、管径有关,开启压力对泄压阀的阻力系数几乎没有影响。 相似文献
18.
在大型循环流化床装置上,通过改变负压差立管上的插板阀的开度,测定不同颗粒质量流率条件下插板阀上下的流态和脉动压力,以此分析插板阀对下料过程颗粒质量流率的调控机制。实验结果表明,对于立管的下料过程插板阀的开度存在一个临界开度,将插板阀的开度范围划分为非可控制区和可控制区。当插板阀的开度大于临界开度时,处于非可控制区,不能进行颗粒质量流率的调节,此时插板阀上下的流态一致,脉动压力曲线相似;当插板阀的开度小于临界开度时,处于可控制区,可以进行颗粒质量流率的调节,此时插板阀上的流态是移动床,阀下的流态是雨状下落流,上下的脉动压力曲线不同。 相似文献
19.
Dmitry Eskin 《加拿大化工杂志》2013,91(3):524-531
An engineering model of a transient laminar flow from a pressurised vessel through a long microchannel under a condition of a rapid valve opening at a channel outlet is developed. A valve at the channel outlet, which is opening with a given speed, is modelled as a time‐dependent boundary condition. Transient flows are investigated numerically by the method of characteristics. The calculations show that variations of pressure and velocity distributions along the channel over time, caused by a transient flow regime, decrease with a decrease in the channel diameter and the channel length, an increase in the time of valve opening and an increase in the fluid viscosity. © 2012 Canadian Society for Chemical Engineering 相似文献
20.
Sequential injection molding using a valve‐gate‐controlled hot runner system has attracted attention for industrial applications in recent years. Because of the complexity of the operation mechanisms, a commercial valve gate usually delays for about 0.3–0.5 s once the valve‐opening command is given. The signal‐to‐operation delay is acceptable for the conventional injection molding of large parts. However, this operation delay limits its application to thin‐wall molded parts for computer, communication, and consumer electronics, for which the required filling time is very short. In this study, a gas‐driven fast‐response sequential‐valve‐gate system was developed for thin‐wall injection molding by the adoption of valve‐gate control performance. The characteristics and verifications of the valve‐gate opening were monitored with a charge‐coupled device (CCD) camera (nonmelt condition) and cavity pressure transducers and an accelerometer (melt‐filled condition). The influence of the tolerance between the inner piston and cylinder and the gas pressure on the valve‐gate opening was investigated in detail. Tensile bar parts 1 mm thick were used for the molding experiments. The delay time has been found to be intimately related to the response of the gas‐pressure delivery controlling the valve‐gate movement. In a nonmelt environment, the delay time of the valve‐gate opening decreases with increasing driven gas slightly. In a melt‐filled environment, the delay time is quite sensitive to the operating gas pressure because of the extra resistance between the shaft and the melt. A threshold pressure as high as 100 bar is required to keep the delay time below 15 ms. With the proper choice of the piston size and driven gas pressure, the delay time can be reduced to about 8 ms in a nonmelt environment and to about 12 ms in a melt‐filled environment. Molding using this improved system for sequential valve opening can provide thin‐wall injection parts without a weld line, and good cosmetic quality and better tensile strength require a lower injection pressure than molding using single‐gate and concurrent‐valve‐gate opening. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 1969–1977, 2005 相似文献