Waermeaustauscher mit vergroesserter Oberflaeche und Verfahren zu seiner Herstellung

摘要

1,163,331. Making heat exchangers; shearing; welding by pressure. D. DALIN. 30 Sept., 1966 [30 Sept., 1965], No. 43814/66. Headings B3A, B3R and B3W. [Also in Division F4] A method of making a heat exchanger comprises forming an elongated bimetallic strip having a core of good heat conductivity metal encased in a sheath of corrosion resistant material, forming the strip into a row of spaced apart, but connected fingers, welding the strip to a heat conducting wall of the exchanger with the strip fingers projecting from the wall as extended surface, and pressing the strip against the wall with sufficient force to compact the core metal. The strip is made from a copper or aluminium core with a stainless steel sheath and in one embodiment two adjacent strips are wound helically around a stainless steel tube 20. In an alternative embodiment, the heat conducting wall is flat instead of tubular. The inner bends 24 are connected to terminals 27, 271 of a source of welding current by electrodes 28, 281 so that the current flows through the intervening section of tube wall. The strips are pressed by tools which act after the welding operation, or the electrodes may be forced against the bends 24 after the flow of welding current is stopped. The strips may be flat or round, Figs. 4, 5 (not shown) and the extreme ends are sealed by the sheath material. Alternatively the strips may be made by passing a heated copper or aluminium ribbon 42 and heated stainless steel ribbons 41, 43 between rolls 46, 47, which initially compact the ribbons and turn in the edge portions of ribbons 41, 43. A second set of rolls 49, 50 bonds together the edge portions and the strip may be reheated for a shearing operation wherein an interleaved comb-like structure is formed. Rolls 51, 52 and 53, 54 have knife edges which shear the strip into a pair of combs (56) having interengaged teeth (57), Fig. 12 (not shown), and the rolls coact to shape the sheath so that the core is completely enclosed. The strip may also be sheared so as to form combs 60, 61, the latter having two rows of teeth, which may be aligned or staggered, and which are bent upwardly. The teeth of the comb 60 may be bent similarly. The comb 61 is secured to a tube 65 by projecting molten metal from a nozzle 66, the subsequent pressure being applied by a roller 67. Pairs of combs 60 are similarly secured, Fig. 27 (not shown).