DOWN-HOLE FILTER Russian patent published in 1999 - IPC

FIELD: oil production industry. SUBSTANCE: down-hole filter can be used for protection of down-hole equipment at recovering liquid products from loose-cemented reservoirs. Device has perforated body, and element which is axially movable within limited range. Element is installed between steps inside perforated body. Hose-like screen is slipped over extension-compression spring. Hose-like screen is made with weaving which is bevelled with respect to hose axis. Sides of screen cells are not parallel and not perpendicular to generant of screen. Liquid enters filter through its body. Filtration is carried out on hose-like screen. Element which is axially movable within limited range is subjected to oscillations and in result it changes configuration of screen cells. Thus filter is made self-cleaning. Application of aforesaid embodiment of down-hole filter features high performance characteristics. EFFECT: higher efficiency. 2 dwg