Abstract: Method and apparatus for butt welding the edge faces of metal skelp which has been heated to a temperature of at least 1000.degree. F. but below the welding temperature of the metal of the skelp. The skelp is continuously advanced through a furnace in which the skelp is heated to such temperature and then, to forming rolls where the skelp is formed into a substantially complete tube with closely spaced skelp edge faces, to a spacing roll for maintaining the edge faces in closely-spaced relation and to pressure rolls where the edge faces are pressed together. Intermediate the spacing roll and the pressure rolls, the edge faces are heated to welding temperature with an induction coil fed with electrical current having a frequency of at least 10 Khz. The induction coil does not encircle the skelp in its tubular forms and instead, has legs adjacent the edge faces and at opposite sides of the gap between the edge faces.

Abstract: Method and apparatus for manufacturing heat exchanger elements in which metal tubing and metal strip are advanced toward each other to a weld station where they are welded together and the tubing-strip combination are then advanced through a first tube straightener, pulling apparatus, a strip corrugator and second tube straightener. The tubing is also passed through tube straightening and shaping apparatus in advance of the weld point. If the combination is collected after leaving the second straightener, the apparatus which is downstream of the weld point other than the pulling apparatus, is inoperative during the advance of the combination therethrough but the combination is then advanced in the reverse direction through such apparatus which is then operative and cut-off apparatus intermediate the weld point and the first straightener cut the combination into panel element lengths which are transferred to further processing apparatus.

Abstract: A method and apparatus for soldering tubular, metal return bends to the ends of tubes in which the article carrying the tubes with the bends secured thereto is first pivoted around a horizontal axis from a horizontal loading and unloading first position to a second position in which the bends and tube ends are immersed in molten solder in a pot and is then pivoted around such axis into a third position in which the bends are above the ends of the tubes, the solder between the ends of the tubes and the bends being permitted to cool and solidify in the third position. Intermediate the first and second positions and intermediate the second and third positions, pivotally mounted burners heat at least the bends to a temperature at least as high as the melting temperature of the solder, the heating between the second and third positions being for the purposes of causing any solder in the bends to flow out of the bends and of minimizing or eliminating icicles of solder on the bends.