| 摘要 |
A gate valve body member 10 and plastic liner 12 define a flow passage 24 therethrough which communicates with a pair of pipes 34 bolted to the gate body. The liner has a bottom seating surface engageable by the gate 22 and extending from a central point outward to the sides of the flow passage. A top opening recess 54 in the liner 12 receives the gate in a slidable sealing fit. The recess and gate are wider than the flow passage and defining walls of the gate receiving recess terminate at the bottom intermediate the center and sides of the seating surface to provide side sealing and pressure backing support in both directions of flow for a lower portion of the gate and particularly a support below the horizontal center line of the flow passage. The seating surface includes a central arcuate surface portion and straight surface portions joined therewith and extending outwardly to the sides, the bottom edge of the gate being configured to fit the arcuate and straight surface portions. The bottom termination of the recess is approximately at the juncture between the central arcuate surface portion and the straight surface portions. Portions of the recess defining walls are relieved to reduce friction of sliding movement of the gate. |
