Air Torque Pneumatic Actuator 3 Way Ball Valve And Actuator

The rotary vane style pneumatic actuator works similar to the piston style pneumatic actuator having two pressurized chambers. Instead of a cylinder form factor, the housing is shaped like a pie wedge. A paddle with an output shaft separates the two chambers. Varying the differential across the paddle moves the paddle and output shaft accordingly through its 90 degrees of travel.

Use of a pneumatic actuator with modern controls typically requires an analog to pressure converter for delivering a control signal setpoint and some type of positioner that translates the physical position of the actuator into an analog or digital position feedback signal.

Some characteristics of pneumatic actuators are that they are capable of modulating process control and can handle high torque loads, but since the power source is a compressible gas, they are prone to stick/slip response, limit cycling, and tend to have performance inconsistency. Performance degradation occurs quickly, particularly when the high level of maintenance requirements are not kept up with.