PUMP UNIT Russian patent published in 2010 - IPC F04B47/08 

FIELD: engines and pumps.

SUBSTANCE: pump unit comprises housing with chambers accommodating plunger pumps and control unit representing a spool hydraulic control valve. Housing pumping chambers with intake and discharge channels accommodate check valves to be communicated with hole clearance and chamber of oil-well tubing. Every plunger pump represents a plunger with plunger shell moving thereon. The unit comprises also electro hydraulically driven oil pump station arranged on the pump to communicate with plunger shell chambers via aforesaid spool hydraulic control valve and discharge and drain channels and rod-type hydraulic control valves fitted in pump plungers. Rods of said valves con interact with plunger shells. Spool hydraulic control valve faces accommodate throttling elements that can be communicated with oil pump station drain channel and coils to make chambers together with said throttling elements. Every said chamber can communicate, via rod-type hydraulic control valve, with plunger shell chamber and oil pump station pressure channel.

EFFECT: stable operation, simplified design.

1 dwg