GB975380A - Torch with igniter - Google Patents

Abstract

975,380. Igniting gas burners. HARRIS CALORIFIC CO. Aug. 29, 1962 [Sept. 5, 1961], No. 33172/62. Headings F4F and F4T. [Also in Division H2] A gas-burning torch includes a piezo-electric crystal 83 for producing an ignition spark across a gap in its nozzle D. The crystal 83 is contained in, and insulated from, a cylinder 81 screwed into a valve housing A, and is compressed by a plunger 90 slidable in the cylinder 81 by a cam mechanism 82 comprising an operating plunger 102 and a cam block 96 having disposed therebetween a spring-urged roller 94. The plunger 90 engages a rubber pressure pad 87 separated from the piezoelectric crystal 83 by a pressure disc 89 and an insulation disc 88. The cam block 96 has an inclined and a bottom surface which coact with the roller 94 to cause the plunger 90 to move first gradually towards the crystal and then abruptly away from the crystal, as an operating plunger 102 is raised by a handle E pivoted to the housing A. The abrupt release of the plunger 90 from the crystal 83 generates a voltage in a wire 85 connected at one end to the crystal contact base 86 and at the other end to one side of a spark gap in the nozzle D. The handle E also coacts with valve-operating plungers 31 (not shown), 46 and 60.which control respectively the oxygen, gas and cutting oxygen valves. The oxygen cutting valve 54 (Fig. 3), comprises a head 57 biased to the closed position by a spring 59 and having a bore 58 which slidably receives the shank 61 of the plunger 60. The oxygen and gas valves are of similar construction. Two adjusting valves (Fig. 7, not shown), are provided in the valve housing A for regulating the proportion of oxygen and gas. A mixture plug 142 is threaded into the torch head B, Fig. 9, and has a chamber 144 for gas supplied from a tube 110, and a chamber 147 for oxygen supplied from a tube 112, the tubes being connected to the valve housing A. The mixture passes into a passage 179 in the nozzle D which is formed by an outer sleeve 160 electrically insulated from an inner core 170 connected to the wire 85 and having an axial oxygen-cutting passage 174. An outlet chamber 192 is provided between the lower portions of the sleeve and core, the spark gap being defined by the gap between the peripheral edges thereof. In Figs. 16-19 (not shown), various arrangements of nozzles are depicted. In one construction the annular passage for the mixture is divided into a plurality of velocity passages and a bleed passage is provided which connects the velocity passage to the centrally disposed oxygencutting passage. The oxygen cutting passage has a layer of insulation covered by a conductive coating connected to the wire 85 and the spark gap is defined by the periphery of the coating and the inner sleeve adjacent thereto. An outlet chamber may or may not be provided between the lower end of the sleeve and core. In a second construction the spark gap is located in a passageway leading from the outlet chamber.