Valve sealing and valve quality and function are closely related

Valve sealing is a measure of valve performance and quality an important indicator. Valve leakage serious threat to the normal operation of the device, and the operation of the valve is difficult to find whether there is internal leakage, the survey results show that various petrochemical companies use different degrees of internal leakage problems exist. The reasons for the valve plate, the valve seat sealing surface material does not meet the requirements, processing accuracy is not enough, the valve disc, valve seat wedge angle does not match the sealing surface width varies, poor fit, the gate is not in place, off Immortality and other factors. As for the Z41Y-25, the sealing surface material code Y should refer to the sealing material in the relatively soft hardness of the sealing surface material, the corresponding other sealing surface material should obviously be at least cemented carbide, but in fact there Valve only one of the sealing surface hardfacing alloy, while the other sealing surface is carbon steel body material, put into use after a long time because of wear and tear caused by internal leakage phenomenon. Another example is the choice of a ducted butterfly valve system, seat sealing material using PTFE. From the use of operating conditions, the requirements are not high, are room temperature and pressure, but in the course of the trial found that a large number of valves are not strict, serious leakage, so that can not be used normally, and finally had to replace the gate valve . Remove the inspection found that close the valve plate and the valve seat has a great gap, or even light. Analysis of the reasons may have the following points! Valve seal deputy structural design is unreasonable or manufacturing and assembly accuracy up to the requirements; valve installation is not required to make it to withstand excessive force construction; construction process, slag, sand, metal debris and other impurities into the valve cavity , So that the sealing effect is affected. In fact, a more practical and fundamental reason is that some of the manufacturing, transportation or installation processes are not required by the standards.