Patent ID: 8202080

Claim:
A plurality of stackable valves where each valve is characterized by: an operating chamber ring ( 108 ) having a flat ring shaped body with a plurality of tabs ( 230 ) where the plurality of tabs ( 230 ) are spaced around the outer perimeter of the flat ring shaped body and extend downward from a bottom side of the flat ring shaped body; a control chamber ring ( 106 ) stacked on top of the operating chamber ring ( 108 ) where the control chamber ring ( 106 ) has a flat ring shaped top with a first cylindrical section ( 344 ) extending downward from an outer diameter of the flat ring shaped top and a second cylindrical section ( 346 ) extending downward from an inner diameter of the flat ring shaped top and where a bottom of the first cylindrical section ( 344 ) rest on a top side of the operating chamber ring ( 108 ) and where a plurality of slots ( 450 ) are formed in the bottom of the first cylindrical section ( 344 ); a valve piston ( 110 ) captured between the operating chamber ring ( 108 ) and the control chamber ring ( 106 ) where the valve piston ( 110 ) has a generally flat disk shaped top with a third cylindrical section extending downwards at an inner diameter of the generally flat disk shaped top and where a bottom surface ( 466 ) of the third cylindrical section forms a sealing surface ( 466 ), the valve piston ( 110 ) configured to move between an open position and a closed position by moving along the cylindrical axis of the third cylindrical section.