| 摘要 |
BUTTERFLY VALVE THRUPORT SEAL A butterfly valve in which a gasket is secured about the vane periphery and in cooperation with an annular body seat effects a seal for closure of the valve passage. Supporting the gasket in a manner to enable controlled enlargement by a locally applied compression force is an annular recess in the vane face inwardly extending from the periphery and a radial clamping ring securing the gasket in the recess. A plurality of screw fasteners extending through the ring and gasket into the vane body operate when tightened to radially enlarge the elastomer for increasing its sealing capability against the seat. Combined surface interference afforded by each of the ring and recess radially constrain the gasket between the ring and vane enabling the energy of compression imposed by screw tightening to remain stored. In this manner the effected enlargement is substantially restricted to within a controlled peripheral portion of the gasket. Because of the imposed constraint, the adjusted seating surface of the gasket is substantially maintained repeatedly during subsequent operating cycles of the valve. |
