GB1216354A - Ball valves - Google Patents

Abstract

1,216,354. Valves. HILLS-McCANNA CO. 10 Oct., 1968, No. 48087/68. Heading F2V. The housing 12 of a rotary ball valve 10, which is adapted for use in a corrosive environment, has formed therein a ball-accommodating chamber 14 and a laterally extending aperture 32, which aperture communicates with the chamber, is so dimensioned as to facilitate the withdrawal therethrough of the ball 20, and is closable by a cap 40. The cap is composed of a bonnet 36 which carries a soft metal sealing element 72, and an annular ring 42 which is sealed with respect to both the aperture and the bonnet, the bonnet and ring defining therebetween a lubricant-containing chamber 90 and being urged towards each other by a series of threaded studs 44 and associated nuts 48, such mutually directed displacement of the bonnet and cap serving to increase the force with which sealing ring 72 is urged against a layer 82 of stellite and hence to increase the degree of sealing between the bonnet and aperture 32. The lower co-acting threads 94, 96 of the bonnet and of each of the studs respectively, are made relatively fine and tight fitting, the upper co-acting threads 102, 118 of each of the studs and associated nuts respectively, are formed relatively coarse and loose fitting and each stud-receiving aperture in the ring 42 is made of greater diameter than the corresponding stud such that lubricant may enter by capillary action between the threaded portions of each nut and stud and between the bonnet and each stud and so prevent the components from freezing together as due to corrosion. In a modification (Fig. 5, not shown) the studs and nuts can be replaced by cap screws (130). In either of the embodiments, the ball shaft 58 is made integral with the ball 20, and is sealed with respect to the bonnet 36 by two glands 62, 64 whose degree of compression is adjustable. The ball is sealed with respect to the chamber 14 by two seats 24, 26 which are retained between the ball and associated seatsupports 28 and 30, respectively.