| 摘要 |
A ball valve of the floating ball variety is provided. Improved sealing subassemblies each comprising a floating seat retainer and a corresponding flexible metallic seat ring provide reliable sealing engagement with both upstream and downstream surfaces of the ball. Each seat retainer moves with the floating ball to maintain annular contact therewith, and retains its corresponding seat ring in constant concentricity with the ball. The seat ring is sealed against the ball by line pressure acting directly on the seat ring on the upstream side, and by line pressure acting on the ball on the downstream side to transmit movement to the seat retainer which then causes the seat ring to perfect a seal against the ball. Each of the seat rings and seat retainers thus independently floats with respect to the valve body. The same sealing subassemblies are utilized on both the upstream and downstream sides of the valve, allowing any side of the valve to be used in any location and making the valve highly versatile. The metallic seat rings are continually in contact with the ball, thereby rendering the valve particularly suitable for handling abrasive fluids.
|
