| 摘要 |
<p>1,203,029. Valves. SAUNDERS VALVE CO. Ltd. 25 Oct., 1967 [8 Nov., 1966], No. 50038/66. Heading F2V. Butterfly valve comprising a casing main part 1 mounting the butterfly disc 3 on a pivot 4 for rotation about an axis offset from the general plane of the disc. A resilient seating ring has a major part 5 located in a recess 6 in one end of the casing part 1, the ring being clamped at a peripheral flange part by a casing flange 2. The ring part 5 is mounted with clearance on both side so as to follow any movement of the disc allowed by working clearance in the pivot, and so maintain sealings under the fluid pressure. The flow passages opened on opposite sides of the disc are arranged, as by recesses 22, 23, to reduce the dynamic torque, by reducing the differential increase in flow passage area as between opposite edges of the disc during opening movement from the seat which would occur with an offset circular disc disposed perpendicularly in a cylindrical bore. The recesses decrease in depth toward the pivot 4. In modifications, the flange is similarly recessed, or there may be a single pair of opposite recesses in the casing main part and flange. Instead of a recess in the flange the bore may be humped up locally at the lower side (Fig. 9, not shown).</p> |
