GB704561A - Improvements in, or relating to, valves - Google Patents

Abstract

704,561. Valves. WALKER, CROSWELLER & CO., Ltd. July 14, 1952 [July 12, 1951], No. 16500/51. Class 135 A valve controlling the flow of fluid, e.g. from two inlet pipes 12, 13 leading from either side of a flow orifice to two outlet pipes 14, 15 leading to a measuring instrument comprises a piston 18 slidable in a body bore from an extreme position in which all passages through the valve are closed, through at least one intermediate position where one of the inlets connects with both outlets, to an opposite extreme position where each inlet connects with a corresponding outlet. As shown in Fig. 1, both inlets are sealed from the outlets by the piston sealing rings 20, 21. When the piston is moved to the left so that ring 20 lies between the edges of inlet groove 12a and ring 21, carried by the piston lies on the right-hand side of the groove 15a, the higher pressure inlet 13 is sealed from the outlet 15, but the lower presssure inlet 12 communicates around the piston neck 22 with both outlets. When the ring 21 lies between the sides of the groove 15a and ring 20 lies on the left-hand edge of groove 12a both inlets communcate with both outlets, and when ring 21 lies on the left-hand side of the groove 15a the inlets 12, 13 connect respectively with each of the outlets 14, 15. The piston is moved by a handle 8 screwing at 8a into the end of the piston, the latter being prevented from rotating by a projection 24 entering a casing hole 5. In the extreme closed position leakage along the handle is prevented by a sealing ring 19 engaging the piston bore while the other extreme position leakage is prevented by the ring 20.