GB1377757A - Method and apparatus for underwater arc welding - Google Patents

Abstract

1377757 Welding by fusion ANNA WELDING CORP 7 Dec 1971 56708/71 Heading B3R In underwater, consumable electrode, A.C. or D.C., arc welding, water is kept from contact with the arc and the welding zone of the workpiece by shielding gas at a pressure exceeding the water pressure. A wire supply reel 38 and wire feed mechanism 60 are enclosed in a submersible water tight box 20 provided with a wire feed speed control knob 40. The box has two openings, one, 32, connected by a conduit 16 to a power source and air blower (10) and a shielding gas source (14) carried by a boat on the water surface (Fig. 1, not shown), and the other, 96, connected by a conduit 74 to a welding gun 64. The power source may be a generator and a rectifier producing D.C. The conduit 16 encloses a power cable 22, an earth wire (24), a shielding gas line 26 and a 110V A.C. feed motor cable 28. The gas source (14) may supply gas both to the conduit 16 and hence the interior of the box 20 and to the gas line 26; alternatively, the conduit 16 and box 20 may be fed with air as from the source (10). Consumable electrode wire 94 from the feed mechanism 60 is passed to the gun through a guide tube 62 carying the gas from the line 26. The gun 64 has a wire feed and welding current control switch 66 and the conduits 16, 74 may be of rubber or rubberized or plastics fabric, said fabric permitting trigger switch actuation therethrough; alternatively, the trigger switch may be disposed on the exterior of the conduit 74. The box 20 may be provided with a gas pressure loss responsive switch for de-energization of the power source. In an alternative embodiment, the box 20 may be entirely jacketed by a cover connected to the conduits 16, 74. The welding gun 64 has its tip extending into a cylindrical housing 120 having, at one end, a transparent viewing plate 122 and, at the other end, a flexible, preferably porous, foam rubber or plastics, gasket 144 for contact, e.g. sliding, with the workpiece. The face of the gasket 144 may have a configuration, e.g. curved, to suit the workpiece. The welding gun has a second switch, 100, for a solenoid-actuated valve controlling gas flow through a debris and water clearing jet 112. The gun tip extends into the housing 120 through a flexible seal 154 of rubber or plastics. Shielding gas from the line 26, or directly from the source above the water surface, is fed to the interior of the housing 120 through a fitting (164) in a housing extension 168 and through an annular, radial, diffuser 172. A light 182, e.g. powered from the cable 28, is directed through a window 180. An L-shaped gas, water and welding particle vent pipe (132) is screwed into the housing at 126 and is adjustable in vent direction to accommodate different welding positions. Shielding gases may be He, Ne, Kr, Xe, Rn, A (e.g. with 1-5% oxygen) or CO 2 alone or as a mixture with any of the aforesaid gases. Inner (electrode surrounding) and outer gas shields may be of the same or different gases. The outer gas shield may be air.