SHUT-OFF VALVE Russian patent published in 1998 - IPC

FIELD: oil production industry. SUBSTANCE: valve can be used in operation and repair of wells. It permits closing of well with lifted down-hole pump for removing sediments accumulated in its space. Valve has body and lock with blind pipe union and through-flow pipe union. Both pipe unions have radial holes. Blind pipe union is fixed in body with its blind end turned upwards for possible conjugation of its outer surface with through-flow pipe union which has additional row of radial holes. This row is away from main row at distance equal to lock stroke and it ensures overflow of well liquid from under blind pipe union into passage above it when valve is in operating position. EFFECT: high efficiency. 2 dwg