GB218717A - Improvements in and relating to connecting tubes together - Google Patents

Abstract

218,717. Marine & Locomotive Superheaters, Ltd., (Compagnie des Surchauffeurs). April 5, 1923. Steam generators.-A number of parallel tubes are connected together at one end in one operation by forcing into the ends which are previously heated to welding temperature, a mandrel having a corresponding number of branches, which are shaped so as to compress and weld the tubes between the branches, then cut the tubes and open out the cut portion to form a common junction piece. The tubes are held at a distance from the end where they are cold and may be placed in a two-part die prior to formation of the junction to equalize the thickness of the junctionpiece. In joining four parallel tubes a mandrel b, Fig. 13, having a central bore and four tapered branches is used which first compress and weld adjacent tubes together as shown in Fig. 16. The tubes are then severed by the mandrel at the junction of the branches, and the outer wall then pressed out by the mandrel as shown in Figs. 15 and 14, and the central portion compressed to form a stem a<2> which may be afterwards cut off. In joining four parallel tubes to a central tube of larger diameter the mandrel b, Fig. 33, is formed with five tapered branches, the tubes being welded as shown at Fig. 37, cut and the walls opened out as shown in Fig. 36, until the junction-piece is shaped to the form shown in Fig. 34. In all forms the surfaces of the branches of the mandrel adjacent their junction 51 are flattened at 52 as shown in Fig. 39 to ensure the cutting of the welded portion and one branch may be larger than the others. Specification 6304/15, [Class 83 (iv), Metals, Working], is referred to.