Abstract: A solar energy collecting system and method suitable for hot water generation using solar energy. The system includes multiport tubes between inlet and outlet manifolds. The tubes are formed of a metallic material, each tube has oppositely-disposed first and second flat surfaces between lateral edges thereof, longitudinally-opposed first and second ends, and multiple fluid channels between the first and second ends that are in fluidic parallel to each other. The inlet and outlet manifolds are coupled to the first and second ends of the tubes so that chambers within the inlet and outlet manifolds are fluidically connected to the fluid channels of the multiport tubes. During operation of the system, a fluid flowing through the fluid channels of the tubes is heated by direct solar radiation impinging the first flat surfaces of the tubes and optionally by reflected solar radiation impinging the second flat surfaces of the tubes.

Abstract: A tube mill apparatus and process for continuously forming and coating a tube with a braze alloy. The apparatus and process produce a continuously moving welded tube by continuously forming and welding a tubing material, after which the welded tube is passed through a sizing station to establish a desired outer shape and desired outer dimensions for the welded tube. The braze alloy is then deposited on a roughened surface of the welded tube that is clean and free of oils and coolants. The braze alloy is deposited with a wire arc spray gun that heats a wire of a metallic material and causes the heated metallic material to travel in a direction transverse to the direction of tube travel and deposit on the roughened surface of the tube to form an adherent layer of the braze alloy. Finally, any bow in the welded tube is removed as the tube travels away from the spray gun.

Abstract: A process for producing high pressure tubing from austenitic stainless steels. The process entails passing a continuous austenitic stainless steel strip through pre-weld rolls enclosed in a forming housing to produce a continuous tubular shape having opposing edges separated by a longitudinal gap. While the gap is maintained with a seam guide and a liquid-free gas mixture of an inert gas and a gaseous flux is directed at the gap and into an interior of the tubular shape, the tubular shape is caused to pass through a high frequency induction coil to cause heating of the opposing edges of the tubular shape. Pressure is then applied to the tubular shape with weld rolls to force the opposing edges together and form a continuous tubing having a continuous butt weld joint. The weld joint is then quenched with an inert gas without the assistance of a liquid coolant.

Abstract: A tube mill apparatus and process for continuously forming and coating a tube with a braze alloy. The apparatus and process produce a continuously moving welded tube by continuously forming and welding a tubing material, after which the welded tube is passed through a sizing station to establish a desired outer shape and desired outer dimensions for the welded tube. The braze alloy is then deposited on a roughened surface of the welded tube that is clean and free of oils and coolants. The braze alloy is deposited with a wire arc spray gun that heats a wire of a metallic material and causes the heated metallic material to travel in a direction transverse to the direction of tube travel and deposit on the roughened surface of the tube to form an adherent layer of the braze alloy. Finally, any bow in the welded tube is removed as the tube travels away from the spray gun.

Abstract: A process and apparatus for continuously forming and coating a tube with a braze alloy. The apparatus includes a device for continuously delivering tubing material to a device that forms a continuous tube from the tubing material, a device for preheating the tube, a device for depositing the braze alloy on the tube, a device for cooling the tube and the braze alloy layer before the surface of the braze alloy layer oxidizes, and optionally a device for sizing the tube. The deposition device includes an enclosure and at least one thermal spray gun that receives a metallic material from the source, heats the metallic material, and deposits the metallic material through an inert gas to form a layer of the braze alloy on the surface of the tube as the tube continuously travels through the enclosure.

Abstract: A process for producing high pressure tubing from austenitic stainless steels. The process entails passing a continuous austenitic stainless steel strip through pre-weld rolls enclosed in a forming housing to produce a continuous tubular shape having opposing edges separated by a longitudinal gap. While the gap is maintained with a seam guide and a liquid-free gas mixture of an inert gas and a gaseous flux is directed at the gap and into an interior of the tubular shape, the tubular shape is caused to pass through a high frequency induction coil to cause heating of the opposing edges of the tubular shape. Pressure is then applied to the tubular shape with weld rolls to force the opposing edges together and form a continuous tubing having a continuous butt weld joint. The weld joint is then quenched with an inert gas without the assistance of a liquid coolant.

Abstract: A process and apparatus for continuously forming and coating a tube with a braze alloy. The apparatus includes a device for continuously delivering tubing material to a device that forms a continuous tube from the tubing material, a device for preheating the tube, a device for depositing the braze alloy on the tube, a device for cooling the tube and the braze alloy layer before the surface of the braze alloy layer oxidizes, and optionally a device for sizing the tube. The deposition device includes an enclosure and at least one thermal spray gun that receives a metallic material from the source, heats the metallic material, and deposits the metallic material through an inert gas to form a layer of the braze alloy on the surface of the tube as the tube continuously travels through the enclosure.

Abstract: A roll assembly suitable for use in the production of thin-wall heat exchanger tubes using a high-frequency induction welding tubemill. The roll assembly includes a roll portion that has an arcuate precision profile that defines one-half of the desired cross-sectional shape of the tube being produced by the tubemill. The assembly further includes a shaft portion that directly supports the roll portion so as to serve as a journal bearing for the assembly. At least the bearing surfaces, and preferably the entire roll assembly is formed from ceramic or ceramic composite materials, without any separate bearing components. Moreover, the roll portion of the assembly is formed from a different material than the shaft portion, in a combination that reduces wear between the bearing surfaces of the roll and shaft portions.