Oilfield Downhole Full Opening Safety Valve FOSV

BACK PRESSURE VALVE (INSIDE BOP/ GRAY VALVE) is a heavy-duty drop check valve that is positioned in the drill string to control formation pressure during kicks. It controls the backflow through the inside of the drill pipe itself, preventing damage to the swivel, drilling hose, standpipe and circulation equipment. During normal circulation of drilling fluids down the drill pipe, the valve remains open to permit the flow through it. A conical plug, or dart, minimizes the erosive action of the drilling fluid on the valve seat and assures a long lasting seal between the valve dart and valve seat.When any backflow occurs, the valve closes automatically to contain it, protecting the drilling equipment as well as controlling the kick that could otherwise lead to a blowout.