Pneumatically fixed (metal-sealed) ball valves can be closed tightly with pneumatic actuators that rotate 90 degrees with air supply and a small turning torque. The fully equal valve body cavity provides a low-resistance, straight-through flow path for the medium. Ball valves are generally considered to be most suitable for direct opening and closing, but recent developments have designed ball valves to throttle and control flow. The main feature of the ball valve is its compact structure, easy to operate and maintain, suitable for general working media such as water, solvents, acids and natural gas, but also suitable for media with harsh working conditions, such as oxygen, hydrogen peroxide, methane and ethylene.