DEVICE FOR WELLHEAD SEALING Russian patent published in 1999 - IPC

FIELD: downhole equipment; applicable in well sealing in cases when blowout preventer is absent and casing string is already run-in. SUBSTANCE: device consists of suspension body with thread on inner diameter for joining with valve body. Installed threadedly inside valve body is seat. There is shutoff member with rod and threaded ring. Upper part of shutoff member and rod lower part are located in central holes of seat and threaded ring as in guides. Upper part of shutoff member has recesses. Exterior surface of valve body has annular grooves in which main and standby flexible rings are installed. In case of necessity of solution injection or pressure relief, shutoff member is pressed out, spring is compressed and solution is injected through recesses of upper part of shutoff member. Upon releasing of force exerted on shutoff member, spring returns it to initial position, i.e. to closed position. EFFECT: increased reliability of wellhead sealing, extended functional potentialities of device operation. 4 cl, 1 dwg