LEGESINSTELLNINGSANORDNING FOR ETT PNEUMATISKT VENTILMANOVRERINGSDON

摘要

A pneumatic valve actuator having a rotatable output shaft is provided with a valve positioner comprising an axially displaceable spool valve and a pneumatic transducer responsive to applied signal air pressure for displacing the spool valve away from a neutral position to effect rotation of the actuator output shaft. The actuator output shaft is gear-connected to an element which rotates with the output shaft, and an elongated cantilever beam spring attached at one end to the rotatable element extends in a direction transverse to the axis of rotation of said element to the transducer for providing a feedback force which balances the control signal responsive transducer force when the actuator output shaft has rotated to a desired position.