XIRXULATION VALVE Russian patent published in 2003 - IPC

FIELD: downhole operating equipment; applicable in recovery of oil and gas, in killing, washing and completion of wells. SUBSTANCE: circulation valve has hollow body with windows and connecting threads, sealing rings, spring-loaded slide valve, piston step couple. Spring-loaded slide valve is installed on body for regulation of spring force by stop motion and closes windows with its skirt in extreme lower position. Piston couple is formed by slide valve, body and sealing members located in gaps between them and hydraulically connected with body cavity through hole made in body. Sealing members are made in form of deformed self-sealing collars from elastomer. Steps of piston couple are made with variable section for changing the value of annular area of piston step couple depending on position of slide valve in body in position of slide valve corresponding to open state of circulation valve, annular area is maximal. EFFECT: reduced hydraulic resistance of circulation valve with fluid pumped through it. 1 dwg