GB705173A - Improvements in gas water heaters - Google Patents

Abstract

705,173. Valves. VAILLANT, H., [trading as VAILLANT KOMMANDIT GES., J.]. Jan. 9, 1951, No. 632/51. Class 135 In a gas water heater provided with a diaphragm operated water-deficiency safety device, the low pressure side of a throttle in the connection to the cold-water side of the heater is connected to one diaphragm chamber via a passage passing centrally through the diaphragm and the other diaphragm chamber, the latter being connected to the high pressure side of the throttle. Cold water flows from an inlet 2, Fig. 2, past an adjustable throttle 13 into a chamber 14, 22, Fig. 1, where it acts on the under side of a rubber diaphragm 21 controlling the gas valve, through a throttle 16, 16<SP>1</SP> to a low pressure chamber 15, and thence to the cold side of the heater through a connection 5, the chamber 15 being connected by pipe 26 and hollow diaphragm stem 24 to the upper diaphragm chamber 23. The top of the stem 24 is closed by a plate valve 38 which allows water to flow quickly into the chamber 23 to allow a quick closing of the gas valve but throttles the outflow of water to allow a slow opening of the gas valve. Cold water may be passed from the inlet 2 in front of the throttle 13 via passage 17, tap 8 and passage 18 to a mixing outlet 12, while hot water from the hot side 4 of the heater may be passed via tap 9 and passage 11 to the mixing outlet or via passage 10 and outlet 3 to a hot tap. The elastic properties of the diaphragm are retained by gripping the edge between frustoconical flanges 29, 30, on the casing and by having the centre of the diaphragm gripped by an annular ridge in one of two flanges spaced apart by the thickness of the diaphragm.