<p>A subsurface safety valve for wells, including a ball valve closed by well fluid pressure and opened by control fluid pressure supplied from the surface. The ball valve includes a control fluid pressure responsive balancing valve for equalizing pressure across the closed ball valve to relieve the ball valve seating pressure. The ball valve is rotatable on support pins carried by the control fluid pressure responsive piston. A spring acts upwardly on the piston to assist well fluid pressure in overcoming control fluid pressure to close the ball valve.</p>
申请公布号
DE2428804(B2)
申请公布日期
1978.08.17
申请号
DE19742428804
申请日期
1974.06.14
申请人
BAKER INTERNATIONAL CORP., ORANGE, CALIF. (V.ST.A.)