The butterfly plate of the butterfly valve shall be installed in the diameter direction of the pipeline. 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 inspection of valve body is also the key point of the inspection of pneumatic butterfly valve. The main inspection is to check whether the appearance of the main body is kept in a new state and whether there is gas leakage in the flange installed on the main body. If there is more time, the sealing condition of the valve body can be further checked and whether there is large wear loss on the surface. Finally, the condition of the valve surface needs to be checked, Check whether the valve plate operates flexibly,