Abstract: A solar collector unit adapted to be installed between the studs or rafters of a building, the unit comprising one or more strips of thin metal welded to three parallel tubes, the intermediate tube having a bore larger than the bores of the two other tubes and the tubes being connected to headers so that fluid flowing in the two tubes flows through the intermediate tube and so that connections of a fluid source to the tubes is made at one end of the unit. The headers carry brackets by which the unit may be secured to, and supported by, the studs or rafters. The sunlight receiving side of the unit is covered by glazing secured to the building and the opposite side is covered by insulation.

Abstract: A method of manufacturing a solar panel element comprising a metal sheet or sheets secured to fluid-tight tubing substantially continuously along its length by metal which has been heated and cooled, e.g. weld metal, in which the tubing and the metal sheet or sheets are held in contact while they are heated to welding temperature, either forge welding or melting temperature. In the preferred methods, the heating is accomplished by high frequency, electric currents using a proximity conductor. Also, in the preferred methods, the tubing is formed with longitudinal lips as the heating is carried out, and the lips are secured together by welding them together simultaneously with the welding of the sheet or sheets to the tubing.

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: Method and apparatus for processing solar panel elements which have been cut from relatively long lengths of metal tubing secured to metal strip and which are to be joined at their opposite ends to headers. At a first station, the elements are, if necessary, stretched in the longitudinal direction and straightened, and the tube end portions are shaped so as to be substantially circular in cross-section. At a second station, the exterior surfaces of the tube end portions are machined to the desired diameter, and portions of the strip immediately adjacent to the tube end portions are removed. At a third station, the remaining portions of the strip outwardly of the previously removed portions thereof are removed by shearing. The elements are moved step-wise from station to station, and three panel elements may be processed simultaneously.

Abstract: Solder pot apparatus comprising a tank divided into first and second sections by a common wall with holes therein below the level of molten solder in the sections for the transfer of molten metal between the sections. The wall has relatively low heat conductivity. The sections are heated by separately controlled heating elements, the heating elements for the second section having a heating capacity higher than that of the first section, so that solder ingots may be rapidly melted in the second section without substantially affecting the solder temperature in the first section. A ramp extends from the first section to the second section and a powered skimmer stirs metal, and removes dross from metal, in the first section and pushes the dross over the ramp into the second section. Also, the apparatus includes a metal surface level sensor in the second section and signals and an ingot feeder conrolled by the sensor.

Abstract: Heat exchanger elements, particularly for solar panels, comprising metal tubing secured to a metal strip which is wider than the tubing and relatively thin by a weld which is metal of at least one of the tubing and the strip which has melted and cooled, the welding conditions being selected so that molten metal is expelled from between the tubing and the strip at the ends of short intervals and the strength of the weld varies longitudinally of the tubing. High frequency electric welding is used under conditions which cause the expulsion of the molten metal.

Abstract: Method and apparatus for manufacturing a heat exchanger element which comprises a metal tube secured to a metal sheet by metal which has been heated and cooled. Wrinkles in the sheet after the tube has been joined thereto are removed by stretching at least the tube by an amount sufficient to cause the length of the tube to be substantially equal to the length of the outboard edges of the tube. The sheet may also be stretched beyond its elastic limit at the time that the tube is stretched but should not be stretched more than 2.5%.

Abstract: Methods and apparatus for the welding and heat treating of metal parts in which an electric arc extends between a pair of adjacent metal parts or between an electrode and one or more metal parts with the arc traversing the metal part or parts a plurality of times during the heating cycle. For finite length metal parts, i.e. when the surface or surfaces to be heated do not provide closed paths to be followed by the arc, the arc is initiated, caused to follow the surface, extinguished and then reinitiated, or is caused to traverse the surfaces in alternately opposite directions after initiation. With finite length metal parts, run-off tabs are provided at the ends of the surfaces to prevent overheating at such ends. A magnetic field causes the arc to traverse the surfaces and may be modified in strength or distribution to vary traverse rate.

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.

Abstract: A method and apparatus for modifying the surface properties of a metal part in which electric current having a frequency of at least 3000 Hz is supplied to a narrow area on the part by means of contacts, one at each end of the area, and a proximity conductor or is induced therein by an induction coil until the metal in the area reaches a temperature at least equal to its melting temperature. A material which will alloy with the metal of the part is added to the molten metal so that when the molten metal is cooled an area of an alloy of the metal and the added material is produced. The added material may be in the form of a gas, powder, salt, wire, rod, bar, foil, etc. and may be applied to the area before, during, or after the melting of the metal of the area. The spacing between the proximity conductor or the induction coil and the work is no greater than three times the width of the proximity conductor or the coil conductor.

Abstract: Method and apparatus for welding a metal part, e.g. a tube or strip, to a thin, flexible metal strip using high frequency electric currents in which the part and strip are continuously advanced to a weld point where they are pressed together. In advance of the weld point, high frequency current is supplied to the part and the strip through contacts engaging them so that portions thereof are heated to welding temperature by the time they reach the weld point. From the point of engagement of the contact with the strip or strips to the weld point the strip material is maintained in a fixed path by a rigid member against which the strip is pressed by tensioning the strip with a pad frictionally engaging the strip. If desired, the current may be fed to the contact engaging the part through a proximity conductor to increase the heating of the part relative to the strip.

Abstract: Methods and apparatus for the welding and heat treating of metal parts in which an electric arc extends between a pair of adjacent metal parts or between an electrode and one or more metal parts with the arc traversing the metal part or parts a plurality of times during the heating cycle. For finite length metal parts, i.e. when the surface or surfaces to be heated do not provide closed paths to be followed by the arc, the arc is initiated, caused to follow the surface, extinguished and then reinitiated, or is caused to traverse the surfaces in alternately opposite directions after initiation. With finite length metal parts, run-off tabs are provided at the ends of the surfaces to prevent overheating at such ends. A magnetic field causes the arc to traverse the surfaces and may be modified in strength or distribution to vary traverse rate.

Abstract: Methods for manufacturing heat exchange panels each comprising metal tubes of finite length welded to a metal sheet except at the end portions of the tubes which are secured to headers in fluid-tight relation thereto, in which methods the metal sheet, having end edges and side edges, is formed into a hollow cylinder with the end edges adjacent each other and metal tubing is welded to the cylinder in a spiral path. Welding is interrupted adjacent the end edges and the tubing is cut above the end edges to provide tubes welded to the cylinder except at end portions of the tubes. The end portions of the tubes, after the cylinder-tube combination is formed to the desired shape, e.g., flat, are secured to the headers. If tubes parallel to the side edges of the sheet are desired, the hollow cylinder is formed with adjacent portions of the side edges in axially offset relation prior to welding the tubing to the cylinder.