Under the maximum pressure of the valve, if the maximum temperature does not exceed the temperature limit of the polymer material+one of the seals can use polymer. It is hoped that the throttling capacity of low leakage can be obtained in the metal metal sealed pneumatic ball valve. The spherical surface of foreign high-temperature pneumatic ball valves is chrome plated. The metal sealing element is 316 stainless steel with Stellite alloy surfacing. The valve diameter is less than l4 inch, and the combined value of temperature and pressure is between ANSI150 and 300 (depending on the valve diameter).

Experts suggest that the data of bellows selection should meet the following conditions:
(1) Good plasticity, convenient for processing and forming of bellows, and sufficient hardness and strength can be obtained through subsequent treatment processes (cold work hardening, heat treatment, etc.).
(2) High elastic limit, tensile strength and fatigue strength ensure normal operation of bellows.
(3) Good welding performance, meeting the welding process requirements of bellows in the manufacturing process.
(4) The rotary compensator has good corrosion resistance, which can meet the working requirements of bellows in different environments.