| 摘要 |
<p>NONFLOATING SEAT FOR EXPANDING GATE VALVES To prevent pressure induced floating of the interference fitted seats of expanding gate valves, a seat ring body is provided which is press fitted within the upstream seat recess of a valve body. The seat ring body defines a sealing face of circular form which is disposed for sealing engagement with the segment portion of an expanding gate and segment assembly. The seat ring body also defines an axial extension tube extending upstream from the seat ring body with a circular sealing lip defining the outer periphery thereof being in radial sealing engagement with a reduced diameter portion of the seat recess. The radial extension is pressure yieldable to enhance the radial sealing capability thereof and defines a pressure responsive area that is equal to or less than the pressure responsive area of the sealing face.</p> |
