There are thin wall balls and hollow balls cast abroad, and there are also castings cast at home, but the quality of castings can not pass the standard. Even as qualified parts, they are far from meeting the technical requirements for ball quality. The other is the ball welded with multiple plates, but it is not suitable for batch production because of many welds and complex process. Our method is to replace the traditional welding method with the once forming technology of pipe cold extrusion for the sphere of DN 100. At present, there are also pipes for forming in China, but the traditional method they use abroad is the hydraulic expansion molding process, which is complex and inefficient. For the production of large balls, we have also found out a different processing method, called plate forming process. This method is used to reduce the dead weight of the pneumatic ball valve and extend the service life of the pneumatic ball valve. The utilization rate of steel is up to more than 60%, almost double the original one. The net weight of the ball after balling is reduced by more than 50%, and there is only one weld, At the non critical non mating surface. It is not difficult to see that the use of thin wall ball and hollow ball technology is not desirable. This not only improves the low-pressure sealing performance, but also extends the service life of pneumatic ball valves. At the same time, the metalworking hours are reduced by more than 2/3 compared with the original.

Pneumatic butterfly valve has the advantages of simple structure, small flow resistance coefficient, straight flow characteristics, and can be used for cutting and regulating. The air consumption of pneumatic butterfly valve is proportional to the valve diameter and cylinder diameter. The larger the cylinder, the more air consumption, and the longer the switching time. The air consumption corresponding to the cylinder is listed below.