| 摘要 |
937,203. Valves. A.P.V. CO. Ltd. Jan. 8, 1960 [Jan. 9, 1959], No. 949/59. Class 135. A circular valve-closure disc 5 with a radiused periphery is provided with a boss 5b rising centrally from one face thereof and at an oblique angle of 45 degrees to the mid-plane of the disc, the boss being extended and reduced in diameter to form an operating spindle 4. The disc 5 is disposed in a chamber 5a formed by enlargements at the abutting ends of two ducts 1, 2, which ends are spigoted and held together by a threaded ring 10; the end of duct 2 is recessed 8 to house a resilient sealing ring 6, e.g. of rubber, to which a nylon or metal backing ring 7 is bonded or mechanically interlocked. The unit 6, 7 is capable of radial movement in the recess 8 so that after initially assembling the parts, the disc 5, which is of greater diameter than the inner diameter of the ring 6, is moved to the closed position and thereby moves the unit 6, 7 to the position where it most effectively seals the disc periphery; the ring 10 is then fully tightened to retain the unit 6, 7 in this position. The inner diameter of the ring 6 is equal to that of the chamber 5a, which latter has a centre offset upwardly from the axis of the ducts 1, 2 to avoid the formation of a shoulder, the lower wall of the chamber being at the same level as the lower point of the ducts. The spindle 4 is journalled in a boss 11, and packing 13 between bosses 5b and 11 is compressed by a spring 14 between the outer end of the spindle 4 and a lever 15 attached thereto. The valve may be cleaned by flowing through it a cleansing liquid.
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