In the 1980s, the development of ball valves in the United States was greatly hindered because the sealing materials were not available at that time,. It is known that the advent of sealing materials in the 1950s has made great progress in the production and development of ball valves. At the same time, thanks to the development of automation, the processing technology of ball valves has been greatly improved, which has greatly improved the accuracy and roughness of materials and accessories. 　　

The pneumatic butterfly valve is mainly used for the control of solid raw materials. It is often placed at the bottom of the tank and can be used as the valve for releasing raw materials, such as the bottom of the cement tank and the stone powder tank. Its main function is to place raw materials and realize the rapid cutting off of raw materials. The main reason is that most of the dust raw materials contain large or small particles, The sealing surface of the valve may be greatly worn. If the valve model is incorrect, the service time of the valve will quickly reduce, which may lead to gas leakage inside the valve in a very short time, affecting the normal use of the valve.