GB554976A - Improvement in and relating to pressure balanced plug valve - Google Patents

Abstract

554,976. Plug cocks. TRIGGS, W. W. (Merco Nordstrom Valve Co.) Nov. 25, 1941, No. 15188. [Class 135] Shoulders on both ends of the plug of a valve abut the casing, are provided with stems exposed to atmospheric pressure, and their outer peripheral surfaces are exposed to annular chambers. In the form shown in Fig. 1, the plug is slightly tapered and provided' with stems 8, 26 and shoulders 10, 25. An inner waslier 12 of metal and an outer washer 13 of resilient material engage the shoulder 10, and a cover' member 14 engages the outer peripheries of similar washers 17, 18, the inner portions of which bear on the shoulder 25 under the action of an adjustable gland 21, metal wear ring 22, rings 23 of resilient material, and a metal ring 24. The chambers 27, 28 are connected by a pair of grooves 31, and a pair of shorter grooves 33 are connected to the chambers when the plug is fully open and closed by means of dwarf grooves in the casing, lubricant being supplied to the grooves 31 from a reservoir 42 through ducts 38 provided with check valves 39 retained in place by pins 40. In a form applicable to cylindrical or tapered valves the shoulder 50, Fig. 3, in proximity to the operating stem is engaged by a metal washer 52 backed by a resilient gasket, and the shoulder 54 by a metal washer 55, acted on by an adjustable member 63 through metal and resilient thrust rings, and the lubricant reservoir is connected to the chamber 28. In a further form shown in Fig. 4, the chambers 27, 28 are not connected to the lubricant system, which supplies a circumferential groove 68 connected permanently by a pair of grooves 69 and in full open and closed positions by a pair of grooves 71 to a circumferential groove 67. Lubricant is also supplied to the washers 83, 85 through ducts 77, 81 leading to annular grooves 76, 79.