ELECTROHYDRAULIC OIL-WELL PUMPING UNIT Russian patent published in 2001 - IPC

FIELD: manufacture of pumps; lifting liquids from deep depths. SUBSTANCE: proposed unit includes submersible electric motor and power pump which are linked kinematically. Working pump is provided with suction and discharge valves and is driven by hydraulic motor; cavities of cylinder of this hydraulic motor are connected with inlet through distributor and with outlet of power drive via safety valve; rod of power pump is connected with rod of working pump via protector. Housing of hydraulic motor is provided with front and rear end plates. Pumping unit is provided with tank equipped with volume compensator whose one section is provided with overflow valve, flow regulator and filter. Protector is made in form of flexible sleeve whose one end is rigidly secured on rod of hydraulic motor and other end is secured on front end plate. Hydraulic motor is provided with hydraulic brake mounted in its rear end plate and rod turn limiter located inside working member of hydraulic motor and rigidly secured on its rear end plate. Cavity of sleeve is connected with tank by means of pipe line. EFFECT: enhanced operational reliability of pumping unit. 6 cl, 3 dwg