| 摘要 |
<p>1,236,879. Valves. LUCEAT. 18 Dec., 1969 [20 Dec., 1968], No. 61653/69. Heading F2V. A seat assembly 10, which is designed to eliminate hammering, comprises a fixed annular and resilient seat 26, and an annular floating seat 42, the two seats being concentric with respect to the axis of flow passage 16 and being disposed on the downstream side of the assembly. The inner seat 42 is movable within an annular recess 36 which communicates with the passage 16 via a plurality of ports 48, and is itself formed with a plurality of axially extending slots 44, such slots co-operating with fixed pins 46 to limit the movement of the seat. In the fully opened condition of a valve incorporating the assembly, the inner seat 42 remains in its lowermost position, i.e. it is contained within the recess 36 (Fig. 1, not shown). Upon the free end 52 of a closure member approaching the assembly, a pressure differential is created across the inner seat 42 as a result of which fluid entering via ports 48 urges the seat into contact with the closure member, as shown. In such condition, a limited flow through the assembly is permitted as long as slots 44 are at least partly outside the recess 36.</p> |
