一种实用、可靠、廉价消除水击的泄压阀

A kind of Applicable, Reliable and Cheap Relief Valves Able to Solve Surge Problems.

目前国内成品油销售系统的发油作业,多数采用一段电磁阀加微机定量控制,这种方法,由于电磁阀关闭时间短,液体的惯性及压缩性,使管路系统发生水击,严重威胁生产安全。在安装电磁阀的旁路上并联一个泄压阀,当电磁阀骤然关闭时,管内液体突然停止流动,邻近阀门的一层厚度为ΔS的液体被压缩,产生一个水击压力增值ΔP,ΔP随ΔS的不断加厚而增大,如果减小ΔS的数值就等于减小了ΔP的值。泄压阀正好解决了这个问题,它在液体被压缩的压力值达到规定值时就开阀,泄放一部分液体,达到消除水击的目的。这种泄压阀动作可靠、价廉、免维修,由于无动力装置,工作时不受智能仪表干预,所以使用范围比较广泛。此外,还推荐采用提前关泵、采集单位时间流量、设定关泵时间,决定何时关阀来消除水击。

So far in China, electro-magnetic valve and a micro computer for quantative control have been used in most of the oil distribution operation of product oil sales systems. Surge usually occurs in the piping system due to the short time it takes to close of electro-magnetic valve and the initia as well as compressibility of the liquid, which severely threatens safe operation. But problems can be solved if a relief valve is installed in parallel with the bypass of the electro-magnetic valve, so that, the liquid inside the piping can suddenly stop flowing if the electro-magnetic valve is stopped all of a sudden , the first layer liquid, with As as its thickness, of the adjacent valve produces an increased surge pressurevalue——△p, which will get higher with As getting thicker. If \s value decreases, it means Ap valuewill decrease as well. The above mentioned pressure relief valve can help solve the problem. It works in this way: It closes when the compressed liquid pressure value reaches the set value and discharges part of the liquid thus avoiding surge occurance. This kind of relief valve is reliable in action, low in cost and free of maintenance, Another advantage is that it has wide scope of application for it has not power device therefore it is not interfered, while working, by any intelligent instrument. On top of what is mentioned above, the following are recommended: shut down the pump ahead of time, acquisite unit time flowrate, set pump shut-down time, decide when to close the valve to avoide surge.