The application of supersonic spraying on metal sealed pneumatic ball valve is introduced today. The supersonic spraying is to burn the fuel gas in oxygen to produce a high-pressure high-speed airflow, and then send the alloy powder into this airflow to spray the workpiece surface (Figure 1). The characteristic of spraying is that the velocity of alloy powder particles exceeds the speed of sound,

(1) Convenient operation, fast opening or closing speed, as long as the rotation is 900 °, the opening to closing action is completed, which is convenient for remote control; (2) Simple structure, small size and light weight of valve actuator; (3) The fluid resistance is small, and its resistance coefficient is equal to that of pipe sections with the same length; (4) Because of its simple structure, it is easy to maintain, and the sealing ring is not fixed, so it is not difficult to remove or replace it; (5) It has a wide range of applications. High temperature solenoid valves can be used from small to several millimeters and from high to high pressure; (6) Reliable and compact, the current sealing material of electric ball valve can be widely used even in vacuum system; (7) In the fully closed or fully open state, the sealing surface and medium of the ball and the valve seat can be isolated, and the medium will not cause erosion of the sealing surface when passing through.