GB1367471A - Heat exchangers - Google Patents

Abstract

1367471 Heat exchangers D MULOCKBENTLEY & ASSOCIATES (PTY) Ltd 22 Nov 1971 [27 Nov 1970] 54147/71 Heading F4S In a heat exchanger particularly for use in dry cooling towers and comprising a plurality of spaced apart fluid conduits 10 of flattened cross-section extending between headers (12, 14, Fig. 1) with fins 22 interposed between adjacent conduits, the fins 22 are made from metal ribbon 38 which is bent or wound to form a flattened coil, the length of each fin 22 in the direction of air flow through the exchanger being in the range 3 to 6 millimetres. The ratios Cu/L and Cp/L lie respectively in the ranges 0À25 to 2 and 0À5 to 2À2, where Cp and Cn are the distances in millimetres between adjacent fins measured respectively in the direction of air flow and normal to the direction of air flow. The fins are preferably of aerofoil cross-section (see Fig. 4). The roots 40 of the fins are seated between stiffening corrugations (20, Fig. 7) formed in the conduit walls. The assembly of fins and conduits are held together between cheek plates 24 by a series of transverse bolts or studs 26 and nuts 28. The degree of tightening applied to the assembly may be such that an initial convexity (30, Fig. 6) of the conduit walls is fattened out (32, Fig. 6). Compression springs 34 may be interposed between the nuts 28 and the cheek plates. A pliant packing (36, Fig. 5) with good thermal conductivity can be inserted between the fins and the conduits.