Pneumatic control valve is a compressed air as power source to the actuator cylinder, and the help of electric valve positioner, converters, solenoid valves, valves and other accessories to secure his position to drive the valve to achieve switching capacity or proportional adjustment, receiving industrial automation control system adjusting the control signal to complete the flue gas medium (mainly air, nitrogen, oxygen, hydrogen, natural gas, coal gas, liquefied petroleum gas, carbon dioxide, etc.) of the flow rate, pressure, temperature and other process parameters.