Patent GB-932392-A (GB)
Title: Gas igniter
IPC: F23Q7/10
Filed: 1959-04-17
Abstract: 932,392. Igniting gas burners. G. DAVIES, and H. A. WALFORD. July 15, 1960 [April 17, 1959; July 10, 1959], Nos. 13270/59 and 23866/59. Classes 75 (1) and 75 (3). [Also in Group XXIX] A gas ignition head for lighting a main burner 20 Figs. 3 4, comprises a conduit 12, Fig. 1, supplied with gas and an electro-catalytic filament 14 of less than ten millionths of an ounce in weight for igniting the gas. Preferably the filament is a wire of platinum with 10% of rhodium of 0.001 inch diameter and of a maximum length of # inch. The filament is silver welded to a tongue 16 on the end of the gas conduit 12 and to a further tongue 17 on 12 and separated therefrom by insulation the end of a tube 11 surrounding the gas conduit 13. The filament is protected by a shield 17. A hole may be provided in the side of the conduit to form a small gas jet. In a modified construction used with a gas which is heavier than air the gas falls on to the filament. The head may have two filaments connected in parallel. The filament may be energized by an electron cell but preferably a generator, Figs. 2, 3, actuated by turning a gas tap 21, is used. The gas tap comprises a rotary plate 28 having on its undersurface a part-annular groove 29 adapted to connect a gas inlet passage 24 in the stator of the generator with a gas outlet passage 25, in the stator leading to the main burner 20 and, during an overshoot movement, to connect the inlet passage 24 to a passage 31 in the stator leading to the gas conduit 12 of the ignition head. The rotor 34 of the generator has two permanent magnet poles and is coupled to the rotary plate 28 by a pivoted spring-urged catch 41 engaging a shoulder on the rotor. As the tap 21 is turned to supply gas the rotor rotates and a coil spring 45 is wound up. When the free end 47 of the catch is engaged with a pillar 48 on the stator the catch is released and the coil spring 45 returns the rotor rapidly to generate about 1.25 volts in a coil 37 carried by a soft iron yoke 36 secured to the stator. The catch 41 is released just as the gas starts to flow to the passage 31 leading to the ignition head. The overshoot movement is made against the action of a leaf-spring 51 adapted to engage the pivot pillar of the catch 41 and on release of the tap the leaf spring returns the tap to a position in which gas is supplied to the main burner only. In order to clear air from the gas conduit 12 before the gas is supplied thereto by the partannular groove 29, grooves 54 in the rotor shaft 44 connect the gas inlet passage 24 to the gas outlet passage 31 for the ignition head during the opening movement of the tap. This subsidiary supply of gas is cut off when the rotor is returned by its spring. A single generator may be operated in conjunction with a number of taps and it can be arranged that whichever tap is opened the generator voltage will be connected to the appropriate filament. A flexible gas supply pipe connecting a gas appliance to a fixed tap includes a separate gas channel for the ignition head and conducting wires for the filament. If the ignition head is used to light a pilot burner adapted to light a main burner by flash back the overshoot feature of the gas tap is omitted and the head is supplied with the subsidiary supply through the grooves 54 in the rotor only. The first Provisional Specification describes an apparatus for controlling the gas supply and the electric supply to the ignition head in which a gas chamber is formed between two elastic diaphragms and the inner diaphragm is adapted to actuate a gas valve and an electric switch. The inner diaphragm has a perforation which allows it to return to its initial position a short time after the gas has been supplied. Specification 932,393 is referred to.