GB578491A - Improvements in thermostatic mixing valves - Google Patents

Abstract

578,491. Thermally-actuated valves. PEGLERS, Ltd., and SMITH, C. M. May 8, 1944, No. 8676. [Class 135] A thermostatic mixing valve for controlling the mixture of hot and cold water or of steam and cold water comprises a sleeve valve 18 with ports 27, 28 for the admission of the two fluids, a mixing chamber 14 in which the valve 18 slides, said chamber having inlet ports 16, 17 in its circumferential wall for co-operation with the ports 27, 28 respectively, and a thermal element 19 accommodated in the valve 18 and operating upon an end wall 20 of the valve against a spring 21 manually adjustable by means provided in a detachable cover 11. As shown in Fig. 1, the valve has a casing 10 with hot and cold water inlets 13, 12 to which stop valves are attached. The stop valves may be incorporated in the casing 10 and may be fitted with strainers or check valves. The inlets 12, 13 communicate with the ports 16, 17 which are formed in a renewable bush 15. The hot water port 28 is fully open when the cold water port 27 is closed and the latter is gradually opened as the former is closed upon expansion of the element 19 which comprises a fluid filled bellows. The bellows seats in a recess in the end wall 20 which also provides a seat for the spring 21. The latter is stressed by a nut 22 slidable in guides 26 in the cover 11 by means of screwed spindle 23 with an operating handle 25. Pressure on the two sides of the valve is equalised by ports 32. Baffles 33 deflect the incoming streams away from the thermal element. In a modification axially spaced ports for both fluids are provided in the valve and the renewable seating bush and the valve ports are shrouded by depending baffles. The outlet in this modification is through ports in the end wall 20 and not through a port in the circumferential wall of the valve as in the first modification.