Fixed displacement variable discharge pump

Claim 1

A FIXED DISPLACEMENT VARIABLE DISCHARGE PUMP COMPRISING A PUMP BODY HAVING PARALLEL SPACED-APART SUCTION AND DISCHARGE PORT PLATES THEREIN, MEANS DEFINING A PUMPING CHAMBER, ROTATABLE PUMPING ELEMENTS IN SAID PUMPING CHAMBER, SAID CHAMBER BEING SEALINGLY DISPOSED BETWEEN THE SURFACES OF SAID PORT PLATES, SUCTION PORT MEANS FORMED IN SAID BODY AND SAID SUCTION PORT PALTE AND OPENING INTO SAID CHAMBER ON ONE SIDE OF SAID PUMP ELEMENTS IN POSITION TO OVERLIE A PREDETERMINED PORTION OF ONEHALF OF THE PERIPHERY OF SAID PUMPING ELEMENTS, A ROTATABLE SHAFT HAVING ONE END EXTENDING THROUGH SAID DISCHARGE PORT PLATE AND ABUTTINGLY ENGAGING SAID PUMPING MEANS WITH THE OTHER END THEREOF PROJECTING FROM SAID PUMP BODY, A SPLIT RING INTERPOSED BETWEEN SAID DISCHARGE PORT PLATE AND THE OTHER SIDE OF SAID PUMPING MEANS AND FIXED TO THE DISCHARGE PORT PLATE, THE INNER PERIPHERY OF ONE PART OF SAID SPLIT RING SEALINGLY ENGAGING SAID SHAFT AND THE INNER PERIPHERY OF THE OTHER PART OF THE SPLIT RING HAVING A GREATER RADIUS OF CURVATURE THAN THE RADIUS OF SAID SHAFT SO AS TO COOPERATE THEREWITH TO PROVIDE AN ANNULAR SEMI-CIRCULAR GROOVE ON THE FACE OF SAID DISCHARGE PORT PLATE HAVING ONE AXIAL END THEREOF IN COMMUNICATION WITH THE OTHER HALF OF THE PERIPHERY OF SAID PUMPING MEANS, A PORTION OF THE OTHER AXIAL END OF SAID SEMI-CIRCULAR GROOVE BEING CLOSED BY SAID DISCHARGE PORT PLATE, BYPASS PORT MEANS FORMED IN SAID BODY AND DISCHARGE PORT PLATE COMMUNICATING WITH A LOW PRESSURE SOURCE AND OPENING ON ONE END OF SAID SEMI-CIRCULAR GROOVE, SAID BYPASS AND DISCHARGE PORTS BEING CIRCUMFERENTIALLY SPACED FROM ONE ANOTHER, HIGH PRESSURE PORT MEANS FORMED IN SAID BODY AND SAID DISCHARGE PORT PLATE AND OPENING ON THE OTHER