Patent ID: 7862308

Claim:
A rotary reciprocating pump comprising: i) a pump housing having intake and discharge ports; a shaft driven rotary piston carrier, rotatably carrying a first set of pistons circularly arranged therearound, said pistons extending from a first side thereof; ii) a driven rotary cylinder block having a plurality of cylinder bores therein, circularly arranged therearound for reception of the pistons on one side portion thereof, and having an opposite flat outer side portion having an intake/discharge port therethrough communicating with the cylinder bores; iii) a stationary sloping inner control surface portion in sliding proximity with the outer side portion of the rotating cylinder block, one peripheral portion of the control surface portion configured so that the cylinder block in proximity therewith moves outwardly, away from the piston for intake, and another opposite peripheral portion of the control surface portion configured so that the rotating cylinder block moves inwardly towards the piston, so that the piston bottoms in the bore for discharge, said control surface portion also having grooved openings therethrough to appropriately communicate with the ports to the bore through the cylinder block, said grooved openings also appropriately communicating with intake and discharge ports in the pump housing; iv) a bias means outwardly biasing said cylinder block away from the pistons towards the control surface portion; and v) a discharge pressure manifold full surround the piston carrier and the pistons within the pump housing so that the discharge fluid pressure is maintained on a rod side of the piston, and thereby, the piston rods are generally held in tension and thereby self align within the cylinder blocks.