In pneumatic actuators, compressed air controls the opening and closing of the actuator.
In double-acting actuators, compressed air both opens and closes the valve. In single-acting models, the operation can be arranged so that compressed air both opens and closes the valve, and a spring integrated in the actuator performs an the opposite motion in the case of air pressure loss.
Advantages of the pneumatic actuator as compared to electric actuators include fast operation and vibration resistance capability.
Suitable for both rotary and linear motion valves
Pneumatic actuators can be divided into two groups: rotary motion actuators (90°) suitable in the case of ball valves in cryogenic applications, and linear motion actuators applicable in the case of seat valves.
Pneumatic actuators can be equipped with various limit packages, positioners and magnetic valves.