Air supplied to Port A forces the internal vane to rotate in the body along the fixed seal, with the exhaust air exiting through Port B. The counter-clockwise rotation on the valve stem is then achieved.

Air supplied to Port B forces the internal vane to rotate in the body along the fixed seal, with the exhaust air exiting through Port A. The clockwise rotation on the valve stem is then achieved.

Process Diagram

 

 

 

Vane Type Return

Actuator (VDA / VSR) 

Port A         Port B