DOWNHOLE PRESSURE COMPENSATOR Russian patent published in 2016 - IPC E21B34/06 F16K17/04 

FIELD: mining.

SUBSTANCE: group of inventions relates to a downhole pressure compensating device for use in combination with a downhole tool, comprising a housing with a chamber and an internal hollow section, a first piston dividing chamber into a first section and a second section, first section being in fluid communication with a first fluid port, second section being in fluid communication with a borehole through a second fluid port, and a first spring disposed within second section to exert a pressure on first piston to enable conservation of an overpressure in first section. Furthermore, device comprises a second piston, a second spring disposed between first piston and second piston, and an overpressure channel arranged in first or second piston. When second spring is compressed, overpressure channel provides fluid communication between said first and second sections. Present invention further relates to a downhole system comprising a wireline, a mating tool such as a driving unit and/or an operational tool, and a downhole pressure compensating device according to invention.

EFFECT: higher efficiency of well pressure compensator.

15 cl, 21 dwg