Reversible motor operated valve with spring assist

Claim 1

A motor operated valve comprising: a valve means including a casing having an inlet, an outlet and a valve seat therein, said valve means further including a valve element movably mounted in said casing to control flow therethrough, said valve member mounted for pivotal movement into and out of sealing engagement with said valve seat by means of a valve stem rotatably mounted in said valve casing and extending through said casing to the exterior thereof; and a reversible motor driven actuating means for said valve means, said actuating means including a reversible motor drive unit having an output drive shaft which can be driven in both a clockwise and a counterclockwise direction, said actuating means further including a gear means to operatively connect said motor drive shaft to said valve stem of said valve means so that when said drive shaft of said motor unit is driven in one direction or the other, said valve stem will be rotated to cause said valve element to move between its closed and open position, said actuating means further including a torsion assist spring mounted on the axis of said valve stem, said assist spring adapted to store energy therein continuously as said valve element is rotated from its closed to its open position and to release such stored energy therefrom continuously as said valve element is rotated from its open to its closed position and said assist spring and said actuating means drive the valve stem in the valve closing direction.