| 摘要 |
PURPOSE:To enable mass production and improve the efficiency of fins by a method wherein metal tubes for circulating a heat exchanging medium are laid on the metal fins for heat collection in the welding width of 1.5mm. or more and welded by the method of nonconsumable electrode type welding. CONSTITUTION:The tubes 11 made of metal such as copper are welded on the lower surfaces of the fins 10 made of metal such as copper in the welding width of 1.5mm. or more by stack welding by using the method of nonconsumable electrode type welding, which results in almost no lowering of the efficiency of the fins. The metal fin 10 is prepared by forming a black selective absorption film on a metal plate which has the width of fin of 70-140mm., the full length of 1m or more and the thickness of 0.3-0.5mm., and a plurality thereof are arranged in parallel in the directin of width, whereby a heat collecting plate is formed. On the occasion, as the metal tubes 11, tubes having the thickness of 0.3-1mm. and the outside diameter of 9-15mm. are used, and inside thereof the heat exchanging medium is made to circulate. Moreover, the size of crystal grain in the melted part prepared by the stack welding is set to be 45mu or more, whereby corrosion of the part is prevented. |
