GB673900A - Mixing valves - Google Patents

Abstract

673,900. Valves. ROBERTSHAW-FULTON CONTROLS CO. Aug. 9, 1949 [Oct. 4, 1948], No. 20678/49. Class 135. A mixing valve has valves controlling the flow from each of a plurality of inlet chambers to a mixing chamber and a disc operatively connected to each valve and disposed in the inlet chamber to provide a constant area orifice across which a constant pressure difference is maintained so as to provide a constant outflow from the mixing valve. As shown, the passage of hot and cold water from inlet chambers 13, 14, to a mixing chamber 15 and outlet 19 is controlled by balanced double-beat lift valves 22, 29 connected through loading springs 40, 41, to an equalarmed lever 38, 39, pivoted on the casing and held in a predetermined position by a thermostat 44. The valves carry discs 25, 32, which form with the inlet chamber walls orifices 26, 33, of constant predetermined area, so that, if the inlet pressures vary, the pressure differentials across the orifices move the discs which position the valves to give a constant flow therepast. The outlet temperature is predetermined by the thermal bellows 44 in the mixing chamber which can be manually adjusted, through the pipe 49, by a screwed knob acting on another bellows connected to the pipe so that the lever adjusts the loading on the valves to make the flow past one valve increase and that past the other decrease by an equal amount. The bellows and lever, as a unit, may be adjustable for predetermining the flow from the mixing valve.