DOWN-HOLE FILTER Russian patent published in 1998 - IPC

FIELD: oil and gas production industry. SUBSTANCE: filter has body with circulation holes, and filter element with stringers is installed on body. Located on outer surface of stringers is wire winding. End surface of filter element is rigidly secured on body by annular thrust band. Filter is provided with housing which together with body forms circulation chamber which accommodates covering bush with radial holes and thrust members. One part of thrust members is housed in radial holes of bush. Other part of thrust members is installed in circulation holes of body. Housing and bush are connected by shear members. Circulation holes are slot-type. EFFECT: high efficiency. 2 dwg