GB1245521A - Gas water heater - Google Patents

Abstract

1,245,521. Valves. MATSUSHITA ELECTRIC INDUSTRIAL CO. Ltd. 31 Jan., 1969 [2 Feb., 1968 (2); 24 Sept., 1968], No. 5483/69. Heading F2V. In a gas water heater of the kind in which the gas supply is controlled by applying to opposite sides of a diaphragm the upstream and throat pressures in a Venturi, or other constriction, in the water supply line to the heat exchanger; the effective cross-sectional area of the throat is controlled by a member movable by the hydrodynamic effect of the water flowing in the supply line. Heat exchanger 49 (Fig. 1) is fed with water from an inlet 22 via governor 29, high pressure chamber 21, and Venturi 34. Low pressure chamber 20 is fed with the throat pressure via conduit 35. Gas heater control valve 45 is connected by rod 47 to diaphragm 16 which separates chambers 20, 21 and which carries a throttling member 36 adapted to vary the throat cross-section in response to movement of the diaphragm. In the modification shown in Fig. 4 the Venturi throat 52 is throttled by a member 56 movable against the action of a spring 59 by the water pressure acting on flange 58. In a further modification (Fig. 5, not shown) the tension in spring 59 is adjustable by means of a manually operable screw (61). Another modification (Fig. 6) shows a throttling member 70 provided with an operating head 71 which co-operates with a seat 69 to cut off the supply to water outlet 23 under excess pressure conditions.