Fluid pump or motor

Claim 1

IN A PRESSURE GENERATING PUMP OF THE TYPE INCLUDING A HOUSING CONTAINING INTERMESHING GEARS AND HAVING AN INLET LEADING TO AND AN OUTLET LEADING FROM SAID HOUSING, AN AXIALLY MOVABLE FLOATING RIGID THRUST PLATE HAVING A SEALING SURFACE IN SEALING RELATIONSHIP WITH THE SIDE FACE OF ONE OF SAID GEARS, A PORTION OF THE SIDE OF SAID THRUST PLATE OPPOSITE FROM SAID SEALING SURFACE COMPRISING A PRIMARY MOTIVE SURFACE, A PUMP HOUSING MEMBER FORMING WITH SAID MOTIVE SURFACE A MOTIVE PRESSURE CHAMBER, A PASSAGEWAY COMMUNICATING PUMP GENERATED PRESSURE TO SAID PRESSURE CHAMBER, A PRESSURE GRADIENT OPENING LOCATED RADIALLY OUTWARDLY OF THE ROOT DIAMETER OF THE GEAR TEETH AND EXTENDING THROUGH SAID THRUST PLATE FROM SAID MOTIVE SURFACE SIDE TO SAID SEALING SURFACE SIDE, A CONTINUOUS CIRCULAR GROOVE IN THE MOTIVE SURFACE SIDE OF SAID THRUST PLATE SURROUNDING SAID GRADIENT OPENING AND DEFINING WITH SAID OPENING A SECONDARY ANNULAR MOTIVE SURFACE ON SAID MOTIVE SURFACE SIDE, A CIRCULAR SEALING MEMBER LOCATED IN SAID GROOVE AND COOPERATING WITH SAID PUMP HOUSING MEMBER AND SAID THRUST PLATE FOR SEALING SAID SECONDARY MOTIVE SURFACE FROM THE PRIMARY MOTIVE SURFACE WHICH SURROUNDS THE SECONDARY MOTIVE SURFACE, SAID GRADIENT OPENING BEING ADAPTED TO CONTINUOUSLY COMMUNICATE PRESSURE FLUID TO SAID SECONDARY MOTIVE SURFACE FROM A LOCALIZED PRESSURE AREA ADJACENT SAID GRADIENT OPENING ON THE SEALING SIDE OF THE THRUST PLATE, WHEREBY SAID PRIMARY AND SECONDARY MOTIVE SURFACES ARE SUBJECTABLE TO DIFFERENT PUMP GENERATED PRESSURES DURING OPERATION FOR BALANCING THE THRUST PLATE SEALING FORCE ON THE SIDE FACE OF THE GEAR UNDER VARYING PRESSURE GRADIENT CONDITIONS.