If the valve is in a large throttling range, the back of the butterfly valve plate is prone to cavitation, which will increase the possibility of valve damage. Therefore, generally speaking, pneumatic butterfly valves are used outside 15 °.

Working principle of pneumatic ball valve:
The working principle of pneumatic ball valve is to rotate the valve core to make the valve flow or block. The pneumatic ball valve is light and small in size. The valve body can be integral or combined. Pneumatic ball valve and plug valve belong to the same type of valve, only its closing part is a ball, and the ball rotates around the center line of the valve body to open and close a valve. Pneumatic ball valves mainly include pneumatic regulating ball valves, pneumatic three-way ball valves, pneumatic cut-off ball valves, pneumatic fluorine lined ball valves, pneumatic switch ball valves and other series of products. The pneumatic ball valve is well sealed, simple in structure, easy to maintain, and the sealing surface and spherical surface are often closed, so it is not easy to be eroded by the medium and is applied in many industries. The pneumatic ball valve is compact in structure and easy to operate and maintain. It is suitable for general working media such as water, solvent, acid and natural gas, and also suitable for media with poor working conditions such as oxygen, hydrogen peroxide, methane and ethylene. Pneumatic ball valves are mainly used in pipelines to cut off quickly, distribute and change the flow direction of media. The fluid resistance is small, and its resistance coefficient is equal to that of pipe sections with the same length.