CIRCULATION VALVE Russian patent published in 2003 - IPC

FIELD: underground downhole equipment; applicable in well killing, completion and washing-out. SUBSTANCE: circulation valve includes body in form of double-diameter cylinder with axial channel and seat in bottom, hollow spring-loaded step control valve movably located in body. Control valve is rigidly connected with circular piston and forms circular chamber together with body. Diameter of step circular piston in lower part is larger than in upper part. Device has end valve. Body is detachable in form of upper and lower parts with seat on upper end of body lower part. Valves in body communicating circular chamber with annular space are made longitudinal in pint of body parting. Channel communicating body axial channel with circular chamber is of throttle type. Made in lower part of detachable body is narrowing part with packing ring. End valve embraces upper part of detachable body is narrowing part with packing ring. End valve embraces upper part of detachable body and is engageable with seat on upper end of body lower part. Stroke of hollow step of detachable body upper part. Piston together with packing ring forms sealed joint. EFFECT: higher operate reliability of device with simultaneous increase of efficiency of process operations. 3 dwg