| 摘要 |
Ball valve assembly (100) including a truncated sphere (140) anchored in a two cylindrical retaining members (48, 50) of the ball valve assembly (100), the truncated sphere (140) having a spherical cap sealing face (142). The ball valve assembly (100) also includes a pair of concentrically oriented, tubular sealing pistons (120, 130), each piston (120, 130) exclusively actuable, one relative to the other, into fluid pressured sealing engagement with the spherical cap sealing face (142) in dependence upon whether an experienced fluid pressure at the ball valve assembly (100) is from a top side (102) or an opposite bottom side (104) of the ball valve assembly (100). |
