Patent ID: 7501056

Claim:
Apparatus for cleaning the interior surface of a containment wall containing a water pool, said apparatus comprising: a body adapted to be immersed in said water pool; at least one first discharge outlet on said body oriented to discharge a water flow in a direction acting to move said body in a first direction; at least one second discharge outlet on said body oriented to discharge a water flow in a direction acting to move said body in a second direction different from said first direction; and a propulsion subsystem for selectively providing a water flow to said first discharge outlet or said second discharge outlet, said propulsion subsystem comprising: a valve assembly including an inlet port and first and second outlet ports, said inlet port being adapted to receive a water flow supplied by a positive pressure source, said first outlet port being coupled to said first discharge outlet, and said second outlet port being coupled to said second discharge outlet; a valve element mounted for reciprocal linear movement between first and second positions such that said valve element in said first position closes said second outlet port and in said second position closes said first outlet port; a hydraulic actuator for moving said valve element between said first and second positions, said actuator comprising at least one piston having first and second oppositely directed faces; and means for selectively applying water pressure supplied by said positive pressure source to said faces to selectively move said valve element to said first position or second position.