WELL FILTER Russian patent published in 1999 - IPC

FIELD: oil and gas production industry. SUBSTANCE: this is used at opening of beds. Well filter has casing with holes which are closed with stoppers. Also provided are reversible non-return valves. Stoppers are made in the form of hollow sleeves which are inserted into every casing hole. Stoppers protrude inside casing with their bottom shear part. Reversible non-return vale is represented by sleeve with double-side setting seat, limiting grates, and locking member. Grates are installed in space of sleeve. Locking member is manufactured in the form of ball made of elastically deforming material. Aforesaid embodiment of well filter is of simplified design. EFFECT: higher efficiency. 3 dwg