GB1310107A - Welding methods - Google Patents

Abstract

1310107 Welding by fusion FOSTER WHEELER JOHN BROWN BOILERS Ltd 14 April 1970 [22 April 1969] 20576/69 Heading B3R A method of welding a tube to a tube plate or header comprises locating a spindle 30 in the tube 14 by expanding a lower part 42 of the spindle to grip the tube, and supporting a welding head 90 on a projecting upper part 32 of the spindle so that the head can be rotated relative to the spindle to perform the weld, the depth of insertion of the spindle in the tube being such that, when the welding head is mounted thereon, electrode 100 will be appropriately positioned relative to the area of the weld. As shown at the right-hand side of the Figure, a jig 60 is used to insert the spindle 30 in the tube. The jig makes a snap-fit engagement with the spindle through the agency of balls 70 and a groove 72 in the spindle. A nut 48 on the spindle core is engaged by a hand wheel 64 of the jig while a skirt 74 of the latter abuts the surface of the tube plate when the depth of insertion of the spindle is as desired. Hand wheel 64 is then rotated to draw the spindle core upwards, so expanding its lower portion 42. The jig 60 is then removed from the spindle 30 and welding head 90 inserted in its place (see left-hand side of Figure). The head has a body 92 of boron nitride or talc, with balls for interfitting with spindle groove 72. The torch 96 may comprise a tungsten electrode 100, and inert gas can be directed to the arc. A gear 124 on the head can be connected to a chain or belt drive 126 which can also drive two similar heads simultaneously. A filler ring 20 can be positioned in an annular groove 18 in the tube plate, as disclosed in Specification 1,303,041 to which reference is made.