BOREHOLE PUMP UNIT Russian patent published in 2006 - IPC F04B47/04 

FIELD: oil industry; well hydraulic drives of pump units for lifting stratal liquids from boreholes.

SUBSTANCE: proposed borehole pump unit has intake tank, force pump with drive unit, lifting and pressure pipelines, borehole pump with working chamber incorporating suction and delivery valves, return member, drain pipe, and safety tube. Lifting and pressure pipelines are made in the form of piping string. Force pump is made in the form of dual-action pump and borehole pump, in the form of hydraulic cylinder with delivery and lifting pistons which are rigidly fixed on rod and form working and lifting chambers. Hydraulic cylinder is disposed at bottom of piping string; working chamber communicates through suction valve with borehole inner space and through delivery valve, with inner space of piping string. Lifting chamber communicates with inner space of piping string; return valve is made in the form of weight joined with hydraulic cylinder. Rod is joined with piping string; drain pipe is provided in addition with control valve. Borehole pump can be equipped with several working chambers to enhance delivery at low differential pressures. Rod is provided with bottom return valve for filling piping string as it is immersed in borehole, whenever necessary.

EFFECT: reduced cost, enhanced reliability in any media at high depth irrespective of stratal pressure, enlarged maintenance intervals due to simplified design.

2 cl, 1 dwg