GB1348678A - Tubular heat exchangers and the manufacture thereof - Google Patents

Abstract

1348678 Making heat exchangers PEERLESS OF AMERICA Inc 19 Aug 1971 [2 Nov 1970] 39048/71 Heading B3A [Also in Division F4] In a heat exchanger in which a block 3 of plate fins 4 is mounted on straight passes 20 of a sinuous tube coil 2 comprising several such passes interconnected by bends e.g. 21-25 the fin has at least one open sided marginal edge slot 7 adapted to receive a first of said passes 20, and at least one aperture 10 spaced from the fin edge and adapted to receive two others of said passes 20. As shown in Fig. 2, each slot 7 has a relatively narrow entry portion 11 leading to a larger main portion 12 dimensioned to receive the tube diameter, and each aperture 10 comprises end portions 13, 14 each generally similar in size to the portion 12 of slot 7, and interconnected by a relatively narrow portion 15. Flanges 35 may be formed around the said portions 12, 13 14 for strength and to serve as fin spacers. The tube coil before assembly is shaped as in Fig. 3 with the outermost passes 20 at an angle to the other passes and deformed to a flattened cross-section such as shown in Fig. 4. The bends 21 interconnecting the other passes are also initially of flattened cross-section so that each pair of other passes and the associated bend can be passed on assembly, through aligned apertures 10 in the block of fins. Thereafter the outermost passes 20 are moved inwardly into the main portions 12 of the slots 7 and finally the tube is expanded so that the flattened sections thereof resume a cylindrical form and are held in contact with the fins without the use of a bonding material. During the expansion, dies (D 1 , D 2 , Fig. 5) are used to maintain the outermost passes in position in the slots 7 generally as described in Specification 1,234,270. Fig. 1 shows an arrangement wherein in each vertical row 16, 17, 18, 19 of the passes 20 fluid flow in adjacent passes is in opposite directions. In a further arrangement (Fig. 7) fluid flow is in the same direction in all the passages in any one vertical row but is in opposite directions in adjacent rows. The tube coil 2 is preferably a onepiece structure of aluminium and the tube fins also of aluminium are 0À006 inch thick.