The butterfly plate of the butterfly valve is installed in the diameter direction of the pipeline, and the butterfly plate is driven by the valve rod. In the cylindrical channel of the butterfly valve body, the disc shaped butterfly plate rotates around the axis with a rotation angle of 0 ° - 90 °. When it rotates to 90 °, the valve is fully open. The flow of medium can be controlled by changing the deflection angle of the butterfly plate.

Working principle of pneumatic three piece ball valve: the pneumatic three piece ball valve can be closed tightly only by 90 degree air rotation and very small rotating torque. The completely equal inner cavity of the valve body provides a straight flow passage with little resistance for the medium. It is generally believed that ball valves are most suitable for direct opening and closing, but recent development has designed ball valves to be used for throttling and flow control. The main characteristics of the electric control valve pneumatic three piece ball valve (ball valve) are its compact structure, easy operation and maintenance.