Pneumatic valve actuators adjust valve position by converting air pressure into linear or rotary motion. Pneumatic actuators utilize compressed air to generate the operating energy. Pneumatic actuators can be either spring return or double acting.
The advantages of pneumatic valve actuators are that they are strong, light, simple, and fast. It is a matter of fact, that pneumatic actuators provide more force than any other actuator technology, except hydraulics. The other main advantage is the high speeds which are possible with pneumatic actuators.
The pneumatic actuators can be used as-is (without explosion-proof requirement) even in an area where an explosion-proof actuator is required by law. Actuation speed can be adjusted as desired using a controller.
The disadvantage is that precise position control is not possible except at full stops. These actuators are quick to respond, but are not ideal for environments under high pressures, as gas is compressible.
Response speed becomes slower (due to the compression of air) where the actuator is significantly distant from the supply air source. A larger size pneumatic actuator is required to obtain high output power. Actuation is affected by fluctuation in air pressure and flow rate.