The Finnish company Cupori Group Oy, which in the spring took over the copper business of Outokumpu Copper Tube, now supplies a copper tube with a particularly clean surface. At the Intersolar 2008 in Munich in June the company presented its new “Tub-e” copper tubes, although still under the old name. They are claimed to have a particularly clean surface thanks to a thermal cleaning process. According to Cupori, welding times during absorber manufacture are shorter with the new tubes.
A pure tube is required especially for the solar absorber ultrasound welding process, in order to get an optimal weld with the absorber plate. The higher the friction between tube and plate, the better the two metal parts may be joined together. Cleaner copper tubes have a higher friction and increase the traction. This enables the manufacturer to increase the speed of assembly and reduce the number of rejects. With the cleaner tubes a complex pre-treatment of the weld seam is unnecessary.
“Increasing demand for thermal solar collectors is forcing the industry to increase its capacities and the performance of its manufacturing processes, and to continually improve the quality and durability of solar thermal elements. The ultra-clean quality copper tubing for solar use is the answer to all these demands,“says Cupori in its brochure as an argument for the solar industry. The company supplies its tubes with external diameters of between 6 and 16 mm and wall thicknesses of between 0.35 and 1.5 mm.
This text was written by Joachim Berner, a German journalist and solar thermal expert.