GB528297A - Improvements in or relating to heat exchange elements - Google Patents

Abstract

528,297. Making heat exchangers. CLAYTON DEWANDRE CO., Ltd. May 3, 1939, No. 13226. Convention date, July 12, 1938. [Classes 83 (ii) and 83 (iv)] [Also in Group XIII] Coiling: soldering. Ring shaped heat exchanger tubes of flat section, particularly for surrounding a fan for air heaters for motor cars are formed with flat side walls extending in a plane perpendicular to the axis of the ring and connected by narrow end walls, the side walls being formed from flat strips by winding them edgewise into helical form. A strip 21, Fig. 7, is coiled edgewise on a rotating mandrel 22, creasing and distortion being prevented by a spring-pressed holder 23. The strip may then be drawn into V-form, then formed with flanges 14, 14<SP>1</SP>, Fig. 2, and finally bent into ,oblong section, Fig. 3, and the edges seamed. The tubes may be used in this form or subdivided into ring-sections. Each tube may alternatively be formed from a pair of wound strips 15, 16, Fig. 4, of equal width which are bent to the form shown and provided with reamed edges 20. Other forms are shown in Figs. 5 and 6. In these forms the wound and shaped parts may be assembled by screwing one into the other and then joined together. The ends of the rings 24, Fig. 8, are inserted into walls 24<SP>1</SP> of distributor casings 25 provided with inlet and outlet tubes 26. For this purpose the flat sides of the tubes are grooved at 28 near their ends and the edges are slit and the slit portions bent over to form tapered ends as shown at 30, 31, Fig. 10. The grooves form stops when the ends are inserted into the walls and the projecting parts are flared over to secure them in position. Corrugated strips 27 are placed between the rings. If desired, smaller rings connected with the walls may also be arranged inside the spaces between the inner edges of the rings. After assembly, the article is dipped in molten metal to seal the parts together, excess molten metal being removed by a centrifuge into which the article is placed and rotated round its axis.