ELECTROHYDRAULIC POWER DRIVEN WELL PUMP UNIT Russian patent published in 1998 - IPC

FIELD: lifting liquids from deep wells. SUBSTANCE: pump unit has kinematically coupled submersible electric motor and drive pump, as well as operating pump with admission and delivery valves, and hydraulic motor. Both the latter and the operating pump are barrel and plunger assemblies provided with rods; plunger rods are interconnected. Hydraulic motor barrel spaces communicate through distributor with inlet and outlet of drive pump. Admission valve is installed in plunger and delivery one, in upper part of operating pump barrel. Barrel and plunger of operating pump have holes to receive liquid being extracted. Pump unit is provided with tank that has pressurizer; tank communicates with inlet of drive pump. EFFECT: enlarged functional capabilities of submersible pumps, in particular those used for low-debit wells. 8 cl, 1 dwg