Patent GB-1393561-A (GB)
Title: Welding or cutting torches
Inventor: HOWELL D L
IPC: B23K9/29
Filed: 1972-04-05
Abstract: 1393561 Cutting and welding by fusion HOBART BROS CO 5 April 1972 [22 Sept 1971 4 Nov 1971] 15781/72 Headings B3R and B3V [Also in Divisions H5 and F4] An arc welding or cutting torch comprises means for extracting smoke and fumes from the welding or cutting zone. The torch may be adapted for gas or unshielded, consumable or non-consumable electrode arc-welding or non- consumable arc cutting. Fig. 1 shows gas-shielded consumable electrode welding apparatus using a torch 10 according to the invention. Consumable electrode wire from a reel 17, welding current from a supply 15, and shielding gas from a source 22 are directed to the torch through a control 20 which is connected to a torch handle switch 35. Torch handle cooling in Fig. 1 is effected by water conveyed from a source 40 by pipes 36, 37. A fume extraction line extends from the torch to a vacuum pump 31 via a filter 32. A cable 30 connected to the torch carries the water pipes, control wires, electrode wire, and shielding gas, welding current and fume extraction lines. In Fig. 2 and Fig. 3, the torch comprises an electrode contact tube 55 which is held, in line with the end of a curved wire guide tube 60, by a holder 65 having holes 69 through which shielding gas, carried through guide tube passages 62, is directed into a gas cup 80 having a rim 103. The cup 80 is connected, by an insulating cylinder 75, to the holder 65 and, by three spacers 86, to an outer shell 85 carried by an exhaust jacket 95. Welding fumes are drawn into a fume chamber 92, formed between the jacket 95 and the guide tube 60, via an annular side entrance 100 defined by the gas cup rim 103 and the lower edge 104 of the outer shell 85, the arrangement being such as to minimize the effect of the welding fume exhaust on the shielding gas. The end of a fume conduit 50 is connected to the fume chamber 92 in axial alignment with the chamber end to provide substantially uniform pressure around the entrance 100. The torch is cooled by ambient air drawn in with the smoke or fumes. In the un-shielded consumable electrode torch of Figs. 6-9 (not shown), the handle is cooled by compressed air directed into chambers 154, 155 embracing a fume conduit (150) in said handle. In the gas or un-shielded consumable electrode torch of Figs. 10, 11 (not shown), fume exhaust suction is taken through a Venturi (180) which draws in additional cooling air through the handle and surrounding a handle fume conduit (170). In the gas or un-shielded consumable electrode torch of Figs. 12-15 (not shown), the handle is cooled by water taken through jackets (200), (201) embracing a handle fume conduit (195). In the TIG welding or cutting torch of Fig. 16 (not shown), a fume chamber (240) between the fume entrance (230) and a handle fume conduit (245) is of sufficient volume to ensure substantially uniform pressure around said entrance, and, for handle cooling, additional, air is drawn through an annular space (256) between the fume conduit (245) and a surrounding housing (255) and mixed with the fumes. In the gas-shielded, consumable electrode torch of Figs. 17, 18 (not shown), the head of which is similar to that of Fig. 3, the fume entrance (265) is formed between a back tapered surface (318) on the gas cup (315) and an outwardly flared lower edge (311) of the outer shell (310), a handle fume conduit/external exhaust conduit connection is made sufficiently remote from the entrance (265) to ensure substantially uniform pressure around said entrance, and air cooling of the handle is similar to that of Fig. 16 (not shown).