| 摘要 |
A soft-seated fire-safe ball valve includes a pair of seat assemblies each comprising a rigid reinforcing ring (100), an elastic seat ring (102), and a deformable, heat-resistant secondary seat ring (104) interposed between the elastic seat ring and a shoulder (70). Upon fire damage to the elastic seat ring (102), the secondary seat ring (104) engages the ball member (c) to seal the valve (Fig. 6). Also, a weir ring (130) may be received in the seat ring (102). The weir ring (130) inhibits extrusion of a substantial portion of the seat ring (102) such that the seat assembly operates to maintain a fluid-tight seal upon partial destruction of the elastic seat ring. <IMAGE> |
