Operation and diagnosis of pneumatically operated valves

Pneumatic actuators are mechanical devices used to convert pressure of compressed air or gas in mechanical action. They exercise required air pressure from the compressor to create displacement by moving a piston. Main advantage of pneumatic actuator over electric actuator is that it will always reach predefined safe position even after losing air pressure (most used type of pneumatic actuator is linear or pneumatic cylinder type). There are three types of pneumatic actuators: 1) Linear Actuator or Pneumatic cylinders; 2) Rotary Actuator or Air motors; 3) Limited angle Actuators. The air cylinder is a simple and efficient device for providing linear trust or straight-line motion with a fast response speed, particularly suitable for single purpose applications and /or where rapid movement is required.