Patent ID: 7799221
Filing Date: 2010-09-21
Classification: B01D,F04B,Y02A,Y02W

Abstract:
1. A combined axial-piston liquid pump and energy-recovery pressure exchanger, the liquid pump receiving, at a primary intake port, a primary liquid flow at a designated supply pressure and delivering the primary liquid flow via a primary output port to a pressurized destination at a designated primary flow rate and at a designated increased pressure, the pressure exchanger receiving, at a secondary intake port, a secondary liquid flow at a designated secondary flow rate and at a designated elevated pressure, and delivering the secondary flow via a secondary output port as a discharge at a reduced pressure, while simultaneously delivering recovered energy to the liquid pump for reduced primary energy consumption and accordingly reduced primary operating cost, said combined axial piston liquid pump and energy-recovery pressure exchanger comprising: a rotor-drum configured with a plurality of cylinders arranged in a radial array constituting a set of cylinder bores extending from open ends at the primary end to a transverse bulkhead configured in secondary end region thereof; a primary end block interfacing a flat water-lubricated sliding primary end surface of said rotor-drum: a secondary end block having an inner surface generally facing a secondary end of said rotor-drum; said primary and secondary end blocks being mechanically coupled together so as to constitute an end block assembly flanking and supporting said rotor-drum in a manner to be rotatable about a central axis; a plurality of pistons, each disposed in a corresponding one of the cylinders in an axially and rotationally slidable manner, each piston having a cylindrical-shaped main portion of designated diameter, closely fitted to form a sliding seal in the corresponding cylinder and thus creating at the primary end a primary cylinder chamber having an effective cross-sectional piston area equal to that of the cylinder, each piston configured at the secondary end with an extending drive-rod traversing a slide-bearing configured in the bulkhead of the rotor-drum, thus creating at the secondary end a secondary cylinder chamber having an effective piston area equal to the cross-sectional area of the cylinder minus that of the drive rod; primary valve means providing commutated fluid communication from the primary end of each cylinder in overlapping rotational sequence (1) to the primary intake port so as to draw in primary liquid whenever the corresponding piston is moving away from the primary end during an intake stroke, and (2) alternately to the primary output port so as to deliver primary liquid to and thus apply pressure to the destination whenever the primary end of the piston is moving toward the primary end during an output stroke; and secondary valve means for connecting the secondary end region of each cylinder in overlapping rotational sequence (1) via the secondary intake port to a secondary liquid flow from a high pressure source whenever the piston moves away from the secondary end, driven in part by the high pressure, during an intake stroke, and (2) alternately via the secondary output port to a secondary liquid discharge flow path at reduced pressure whenever the piston moves toward the secondary end during an output stroke; driving means for energizing rotation between said rotor-drum and said end block assembly while also reciprocating the pistons axially in sequence via the drive-rods over a designated stroke length and actuating said primary and secondary valve means in a synchronous operating manner; whereby the pistons are made to perform, at their primary ends, a pumping action that serves to maintain designated elevated working primary pressure input at the destination while, at their secondary ends, the pistons are made to perform work in a pressure exchange that enables energy recovered from the secondary liquid flow to contribute to the primary pumping action and thus reduce overall operating costs.