| 摘要 |
PURPOSE:To facilitate manufacturing of a solar-heat absorbing panel or a plate type heat exchanger and to improve its corrosion resistance, by making common use of spot welding and seam welding to provide a resistance element for the bulging process. CONSTITUTION:Two metal plates 1 formed with openings 2 are superposed on each other and they are joined together by applying seam welding 3 at their peripheral portion. Further, they are welded together by applying spot welding or roll spot welding 6 and seam welding 7 alternately at the portions thereof which are not used as fluid passages. Then, bulging process is carried out by forcing a fluid from the openings 2 under pressure. In the above arrangement, spot welding 6 can be made in two rows between each two adjacent lines of seam welding 7. |
