GB792455A - Improvements in mixing valves - Google Patents

Abstract

792,455. Valves. ROBERTSHAW-FULTON CONTROLS CO. Dec. 9, 1955 [April. 7, 1955], No. 35436/55. Class 135. A hot and cold water mixing valve comprises a valve unit 10, Fig. 1, detachably secured by a single bolt 20 to a manifold fitting 12 having cold and hot water inlets 14, 15 respectively and a pair of outlets 16, one of which may be plugged if not required. Each inlet is fitted with a non-return check valve 42, Fig. 4, which may be positively held on its seat by a screwthreaded plug 34 to prevent leakage from the manifold when the valve unit is disconnected to facilitate repairs to the valve unit. Parallel bosses 55a, 57a on the manifold fitting sealingly connected to complementary bosses 55, 57 on the valve unit connect the inlets 14, 15 through passages 60, 62 to a pressure equalizing chamber 66 in which is slidably mounted in end caps 68, 72, Fig. 6, piston valves 80, 82 connected by rods 84, 88 to a piston 92 subjected on opposite faces to the pressure of cold and hot water so that the pressures of the cold and hot water leaving the chamber and entering a mixing chamber 160, Fig. 2, through ports 102, 104 are the same. The mixing chamber houses a sleeve valve 116 connected to a bellows type thermostat 122 filled with an expansible liquid whereby an increase in pressure causes the bellows to expand against a spring 134 to control the ports 102, 104 and thus the temperature of the mixed water. The bellows is connected to a bush 140 slidable in a casing part 144 and coacts through a ball 138 with a face-cam 154 secured to a stem 148 to adjust the temperature of the mixed water which passes to the outlet (or outlets).