CIRCULATION VALVE Russian patent published in 2002 - IPC

FIELD: oil and gas producing industry; applicable in operation of gas-condensate and oil wells, particularly, in wells whose fluid contains acid components such as H₂S and CO₂. SUBSTANCE: circulation valve consists of coupling with holes, safety ring, plugs wit internal dead channel. Channel is opened from the side of annular space. Plugs are installed in coupling holes with possible breakage under effect of striking rod. Holes in coupling have thread. Plugs are made of cast iron and turned into coupling holes. Safety ring has holes. Tops of plugs are located in said holes of safety ring for possible breakage by action of striking rod on safety ring. Safety ring is made of cast iron. EFFECT: higher degree of reliability and safety in operation. 2 cl, 2 dwg