GB1310101A - Mixer taps or valves - Google Patents

Abstract

1310101 Valves H WATTS 2 April 1970 [10 Jan 1969] 1497/69 Heading F2V Hot and cold water mixing valve comprises a housing 1 with a cylindrical chamber having radial hot and cold water inlet ports 3, 4 and an outlet port 5 spaced axially from the inlet ports. The chamber contains a valve piston 6 which is rotatable to selectively vary the proportions of hot and cold water and axially movable to control the total flow. The piston carries a series of sealing rings such as 8, 9, 13, at least one of these rings being exposed to an inlet port in open position of the valve. The piston is movable axially to closed position in a direction which subjects this ring to the upstream pressure at the moment of closure, and the ring is a slight stretch fit in its groove, whereby nip and wear on this ring are avoided. As shown, opposite ends of the piston are vented at 14, 15. Other embodiments, Figs. 4 to 10 (not shown), are disclosed. In Fig. 4 the exposed ring is of U- section, and the bottom end of the chamber is vented to the top end through a central tube (22) and radial hole (23) in the piston. In Fig. 5 the piston moves downwardly in the closing direction, and has an axial passage closed by an end plug (25) adjacent a control port (10). In Figs. 6-9 the hot and cold water inlet ports are axially spaced and separate sealing rings 9, 9a are exposed respectively to these ports in open position. In Fig. 10 the operating stem (21) is sealed where it extends out of the housing, and the valve is hydraulically balanced. To this end an annular top end (28) of the piston is made equal in area to the bottom end and communicates with it through a central passage 11 and restricted opening (33) to give a dashpot effect.