METHOD TO WITHDRAW FILTER FROM WELL AND DEVICE FOR ITS REALISATION Russian patent published in 2014 - IPC E21B31/00 

FIELD: mining.

SUBSTANCE: device comprises a round body (1) with a cone (20), in which holes (21) are made for electrolyte flow, and in the body wall at the bottom there are four oblong "windows" (15), where thrust electrodes (2) are placed, capable of rotation on their axes (24). Inside the body at the lower end there is a cylindrical bushing (14) inserted with four holes (25) opposite to "windows" for flow of electrolyte. At the outer side of the body, below the "windows" there is a stop in the form of a cylindrical ring (19), where thrust electrodes thrust upon completion of grooves formation. Plate springs (17) are fixed to the cylindrical bushing opposite to "windows". Via a cable (6) the electrodes are connected to a minus terminal of a DC source on day surface. The wall of the withdrawn filter is connected to a plus terminal of the same source of current via a pipe string (7) connected by thread with the upper end of the filter. A cover (12) with holes (13) is screwed into the upper end of the device body for electrolyte flow, and an eye bolt (8) in the centre, connected with the lifting system.

EFFECT: holes in a cover and cone make it possible for electrolyte to flow via a device to electrodes and further, via a check valve of a filter block and sand-gravel fill into annular space.

2 cl, 3 dwg