Variable pre and de-compression control mechanism and method for hydraulic displacement pump

A hydraulic displacement pump, comprising:

• a rotating piston carrier, including a plurality of piston chambers, supported for rotation in a pump casing;
• a plurality of hollow pistons, inserted into said pistons chambers, carried for collective rotation in the pump casing via the piston carrier, the pistons being driven in pumping action via a pair of floating piston plates connected, respectively, to pistons inserted from opposed sides of the piston carrier;
• a pair of respective first and second valve plates, each controlling flow of fluid to each of the plurality of pistons from respective first intake and discharge plenums associated with the pump casing, the valve plates being suspended for incremental rotation in end sections of the casing and opposed to the pistons, the valve plates including respective land areas wherein when an individual one of the pistons is passing the corresponding land area, fluid flow into and out of the piston is momentarily stopped, the valve plates being configured to separately increment in rotation with respect to the rotation of the piston carrier in either a forward or rearward aspect, so as to alter the effective land area of the valve plates with respect to overall pump operation.

A method of controlling noise in a hydraulic displacement pump, the pump including a rotating piston carrier including piston chambers and hollow pistons fed through a pair of opposed incrementally rotatable valve plates positioned on either side of the rotating piston carrier, the method comprising the steps of:

• incrementing the respective valve plates in rotation in opposed directions, one with respect to the other, so as to shorten the effective land area of the valve plates;
• and, adjusting the incremented position of the valve plates to induce pre and decompression within the respective piston chambers during pump operation.

A method of controlling pumping volume in a hydraulic displacement pump, the pump including a rotating piston carrier including piston chambers and pistons fed through a pair of opposed valve plates positioned on either side of the rotating piston carrier, the method comprising the steps of:

• incrementing the respective valve plates in rotation in the same direction, one with respect to the other, so as to shorten the pumping stroke of the respective pistons;
• and, adjusting the incremented position of the valve plates to reduce effective pumping volume within the respective piston chambers to adjust pump throughput.