| 摘要 |
A uni-directional or bi-directional gate valve comprises a seating structure to maintain a fluid-tight seal between an external valve cavity 12 and the upstream and/or downstream portion of a valve bore 10, regardless of pressure differentials between them. Annular seat members 24, 26 of the gate valve are provided within corresponding recesses 20, 22 in the valve body. A dynamic sealing member (38, Fig. 2) is located in annular valve cavity 36 between each annular seat member 24, 26 and each recess 20, 22. The radial position of the dynamic sealing member 38 relative to protruding sealing faces 28, 30 of the annular seat members 24, 26 creates a net force F which always acts in the direction of the valve gate 14 to provide an effective seal, even during in-service testing of seal integrity. |
