WELDING GUN FOR DEEP NARROW GAPS

摘要

A welding gun for welding in narrow gaps is capable of use in gaps of the order of 1.5 cm wide and 30 cm deep. The gun has a width less than the width of the gap. A guiding tube for a consumable electrode conducts the electrode to the gun and the electrode extends centrally through the gun to project from the other end. A pair of tubes carrying a shielding gas extend along the side edges of the gun and are inclined inwardly towards the terminating ends of the tubes to direct the gas towards the welding region in two narrow converging streams. A pair of cooling channels are within the head on either side of the electrode and cooling fluid is circulated through the channels. Coupling means is provided to enable replacement of the head. In a preferred form the ends of the tubes carrying the shielding gas are bevelled or sloped for a distance of several tube diameters back from the ends and on the sides of the tubes against the head. When the head is within the gap, the gap walls restrict gas flow from the bevelled portions, but as the bevelled portions rise above the gap increasing amounts of gas flow with a sideways component to provide improved shielding when the weld nears the surface.