GB546227A - A new or improved safety device for gas burners - Google Patents

Abstract

546,227. Fluid-pressure servomotor control systems. BRITISH BRASS FITTINGS. Ltd., and SALINGER, G. T. June 7, 1941, No. 7235. [Class 135] A safety-device for gas burners of the kind in which the gas supply is controlled by a main valve actuated by gas pressure acting on a diaphragm under the control of a thermally-actuated auxiliary valve subject to the heat of a pilot burner flame has the auxiliary valve so arranged that when its associated thermal element is cold it connects the two chambers on opposite sides of the diaphragm so permitting the main valve to close. As shown in Fig. 1, the main valve 4 is carried by a diaphragm 3 separating a casing into two chambers 1, 2, the chamber 1 being directly connected to the main supply conduit A while the chamber 2 is connected to the supply conduit through an adjustable throttle 6. A narrow bore pipe 8 connects the chamber 2 with a casing housing a spring-loaded valve 12 having an adjustable byepass 14 and actuated by a thermosensitive tube 9 immersed in the water space of a heater F heated by gas passing the valve 4 to a burner E. The safety-device comprises a casing connected by a pipe 16 with the main gas inlet and by a pipe 15 with the casing of the thermostat C if such is used or this is dispensed with the pipes 8 and 15 are connected by a pipe 48. A valve member 21 adapted to cooperate with opposed seatings 19, 20 is actuated by a thermo-sensitive tube 17 acting through a rod 18 and stiff spring 22. To open the main valve a self-closing valve is opened by a push to permit gas to pass from the pipe 16 to a pilot jet 32 in a cap 31 where it is ignited. This flame heats the tube 17 causing the valve 21 to move away from the seat 20 permitting gas to pass to the pilot burner 26 where it is ignited by the flame from the jet 32. Further heating of the tube causes the valves 21 to engage the seat 20 so isolating the chamber 2 from the pipe 16 the pilot flame now being supplied through the pipe 15 from the chamber 2 reduces the pressure in this chamber and permits the main valve to open. Should the pilot flame be extinguished the valve re-establishes communication between the pipes 15 and 16 and allows the main valve to close. In the form shown in Fig. 2 the seat 20 is made adjustable. The tube 17 may be replaced by a bi-metallic strip or disc or by a bellows containing a fluid.