How to Size a Pneumatic Actuator


Sizing a pneumatic actuator can be a very important step in automation design. If it is sized too small, it will be unable to operate the valve. If it is sized too large you could be wasting money or risk damaging the stem of the valve with excessive torque output. Our valve experts use these simple steps in sizing a pneumatic actuator.


1. Gather Information:

Information gathered should be provided by an engineer to ensure accuracy with the specific process conditions in each unique application.

  • The MINIMUM operating pressure.
  • The torque required to operate the valve. For safety, always increase the torque to allow for a safety factor. (For example: break torque x 1.25)
  • Select which actuator you will be using. (Rack and Pinion, Scotch Yoke, Vane, Manual, etc.)
  • The torque charts for the actuator being used. These charts are generally provided by the manufacturer. If you cannot locate the specific torque information, contact our actuation experts for assistance. (For this explanation we will use the Rack and Pinion torque charts from A-T Controls.)


2.  Select Fail Position:

In which position should the actuator fail?