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.

Pneumatic ventilation butterfly valve, characterized by a slit between the valve plate and valve seat, is suitable for use in the environment with poor air circulation.