GB1216138A - Ball valves - Google Patents

Abstract

1,216,138. Valves. HILLS-MeCANNA CO. 9 Oct., 1968, No. 47886/68. Heading F2N. In a rotary ball valve 10, sealing of the flow passages 16, and 18 with respect to a chamber 14, which chamber accommodates the rotary ball 26, is achieved by means of two identical passage encircling structures each of which comprises a resilient seat 70, a metal ring 72 encircling the seat, and a seat support 86. The seat support is sealed with respect to the valve housing 12 by a seal 92, is biased towards the ball by a spring 98, and has its seat-engaging surface 82 curved, the radius of curvature of which surface is identical to the same of the ball 26. The ball and seat support-engaging surfaces of seat 70, present concave surfaces 78 and 80 respectively, the radii of curvature of which surfaces likewise correspond to those of the support and ball, the combined arrangement permitting each seat to move transversely with respect to the flow passage axis in the event of the ball undergoing similarly directioned movement. The ball operating shaft 32 is retained within bearings 36 and 38, and is sealed with respect to a bonnet 22 by two seals 46 and 52, the bonnet being removably retained within a housing bore 24 such that the valve component parts may be removed through the bore 24, and the seals 46 and 52 being compressible into tighter engagement with the shaft 32 by screwing of a nut 58, the nut acting on a washer 60 which encircles the stem in a non-rotatable, axially movable manner, and further coacts with an abutment 62 to limit the rotation of the ball. In an alternative embodiment, Fig. 4, not shown, spring 98 is replaced by a spring which in radial section has a central U-shaped portion and two lateral limbs, the limbs being welded to the bore 16 and support 86.