Valve Positioners

A Valve Positioner works by controlling the air pressure in an actuator until the valve’s stem achieves a position balanced to the output signal.

A Valve Positioner is used to control a valve where accurate and quick control is needed and is normally mounted on the side-yoke or top casing of the pneumatic actuator for sliding stem control valves and near the end-of-shaft for rotary control valve.

Both of these valves will benefit from mechanical feedback linkage connected directly to the valve stem which provide feedback to the process controller.

The process controller instructs the positioner to change position and the feedback linkage reports back to the position confirming that the change has occurred and also the amount the change which has taken place.