GB1537236A - Welding - Google Patents

Abstract

1537236 Welding by fusion WHESSOF Ltd 3 Dec 1975 [6 Dec 1974] 32881/74 Heading B3R In linear, internal orbital or, as shown, external orbital MIG or TIG apparatus, a body carrying a welding electrode, movable relatively to the workpieces and adapted to overlie the welding zone defines in part a welding chamber to which inert gas is fed, and the wall of the body bounding said chamber is stepped to provide a zone of reduced workpiece/body clearance for gas sealing. As shown, an external orbital TIG body I comprising two halves 1a, 1b fast together is rotatably supported by one or, as shown, two hinged clamps 4 engageable with workpiece pipes 3a, 3b by way of radially resiliently movable jaws 7. The body is rotatable by a motor via a flexible drive, a worm, and a worm wheel 9. A tungsten electrode 13 is mounted in a passage 10 providing for inlet of inert shielding gas, gas outlet being by way of workpiece pipe/body clearance. Entry of ambient air into the welding chamber is reduced by provision of body shoulders 2b, seals around the electrode holder, a gas inlet passage diffuser 14 providing a back pressure enabling outward gas bleed, and, at the body half joints, either seals 15 or a restriction enabling gas bleed.