The structure of electric on-off butterfly valve is to adopt the valve body of double clip butterfly valve type, and its inner side is lined with fluorine or rubber, so as to achieve the effect that it can be completely sealed with the butterfly plate and ensure zero leakage of media. Therefore, electric cut-off butterfly valves are widely used in metallurgical, petrochemical, air flow, gas combustion, water supply and drainage and other corrosive media pipelines with medium temperature ≤ 550 degrees, and are the best devices for flow regulation and fluid cut-off. 　　

According to the actuator of the pneumatic control valve and the general combination mode of the valve, if it is a double pilot valve, the actuator will adopt the positive action mode. When the positive and negative installation mode of the control valve is changed, the air on and air off mode will be realized. However, there is only one combination mode of the counter acting actuator, which can form an air to open valve. It is impossible to change the installation mode of the valve so as to realize the change from gas on to gas off, and a new gas off valve must be replaced.