GB717184A - Improvements relating to gas torches - Google Patents

Abstract

717,184. Gas and vapour burners. BURCH, C. R., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Feb 26, 1953 [March 24, 1952], No. 7541/52. Class 75 (1) A gas torch for glassblowing, soldering, brazing &c. has a divergent Venturi-type outlet nozzle arranged to be fed with a mixture of gas and air, and auxiliary heating means are provided for preheating the gas and/or air in its passage to the outlet nozzle. Gas and air are supplied through pipes 7, 8, respectively, to a burner tube 2 and an inner tube 3 coaxial with the latter, through coils 9, 10 surrounding the tubes 2, 3 and heated by a Bunsen burner 11 having outlets 15 and secured by clamps 12 to the pipes 7, 8. The tube 3 terminates in a jet 5 which discharges air into a burner outlet Venturi nozzle 4, spaced therefrom by a small gap through which gas from the tube 2 is entrained by the air flow. The alignment of the jet 5 with the Venturi nozzle 4 may be adjusted by means of three screws 6 engaging the periphery of the tube 3. A radiation shield (not shown) may be arranged about the parts of the torch heated by the burner 11. Also a further tube heated by either the burner 11 or by an additional burner may be arranged around and projecting slightly in front of the nozzle 4 so as to provide a heated sheath of air around the flame at said nozzle. The burner parts 2, 4 and 5 may be of heat resisting stainless steel and the parts 3, 9, 10 of a heat resisting alloy. Alternatively the nozzle 4 and the jet 5 may be fused silica or fireproof glass. To clear carbon accumulation from the rear edge of the Venturi nozzle 4 air may be blown through the gas pipe 7, which has a branch 16 (not shown) for connection with an air supply pipe. The torch may alternatively burn kerosene vapour supplied from the vaporizer of a blowlamp through a needle-valve controlled by-pass, the flame of the blowlamp heating the coils of the torch.