| 摘要 |
A gate valve for controlling fluid flow, with a valve body forming a cylindrical flowbore and a gate cavity intersecting the flowbore to provide opposed openings into the flowbore. Seat pockets formed in the opposed openings, each with a radia l base and a side wall, may optionally include a metal carrier ring. The gate is slidably movable within the valve body between open and closed positions. Annular sea t elements in each seat pocket allow for limited axial movement on opposite sides of the gate, with a first seal surface for sealing against the seat pocket or optional carrier ring, and a second seal surface for sealing against the gate. A non-metallic bridging seal formed as a face seal is provided between the first seal surface of the annular seat element and the seat pocket (or optional carrier ring). The bridging seal bridges any gap formed at the first seal surface of the annular seat element such that sealing engagement is maintained across the gap at all times as the gate moves betwe en open and closed positions, while still permitting the limited axial movement of t he annular seat element. Preferred embodiments of the bridging seal include tongue and groove seals and bridge ring inserts. A secondary seal to the seat pocket may be included as a corner, periphery or faceseal, for example as an O-ring, U-ring or wiper seal.
|
