Patent ID: 6471182
Filing Date: 2002-10-29
Classification: F16K

Abstract:
An actuator for opening and closing a globe valve, the globe valve having a stem through which positioning of the globe valve is achieved, the globe valve being normally biased to an open position, the actuator comprising an electric motor which drives a worm and pinion arrangement, the pinion driving an output gear movable between a base and a raised position within a frame and held in the base position by a compression spring with a similar compression rating to that of the valve shutoff, the output gear driving a worm stem bearing against the stem of the globe valve to move the stem against its bias in one direction to close the globe valve, the output gear and worm stem arranged so that:(a) when the globe valve is fully closed, the worm stem is at its extreme position in said one direction and the output gear then begins to move within its frame from its base to its raised position, a shoulder on the output gear simultaneously moving a first leaf spring to break contact with a first switch and turn off the electric motor with the valve in the closed position; and (b) in the opposite direction, the output gear returns to its base position and then moves the worm stem in an opposite direction to a position where the worm stem moves a second leaf spring to break contact with a second switch to turn off the electric motor with the valve in the open position.