In the actual production process, selecting a pneumatic actuator correctly for pneumatic valves is actually very important, because if the actuator is too large, the valve stem may be subjected to too much force, and if the actuator is too small, it cannot generate enough torque to fully operate the valve.

In general, the selection of pneumatic actuators requires consideration of multiple factors, such as the operating conditions of the valve, operating temperature, operating frequency, management and pressure difference, conveying media (lubrication, drying, mud), etc. In the process of selecting pneumatic actuators, the key points are as follows.

1. Operating thrust: There are two main structures for valve electric devices: one is to output torque directly without a thrust disc; Another approach is to configure a thrust disc, where the output torque is converted into output thrust through the valve stem nut in the thrust disc.

2. Operating torque: Select the most important parameter of the valve electric device, and the output torque of the pneumatic actuator should be 1.2-1.5 times the maximum operating torque of the valve.

3. Valve stem diameter for multi turn open stem valves: If the maximum allowable valve stem diameter of the electric device cannot pass through the valve stem of the matched valve, it cannot be assembled into an electric valve. Therefore, the inner diameter of the hollow output shaft of the electric device must be greater than the outer diameter of the stem of the rising stem valve. For partially rotating valves and non rising stem valves in multi rotating valves, although the diameter of the valve stem does not need to be considered when selecting, the size of the valve stem diameter and keyway should also be fully considered to ensure normal operation after assembly.