GB653570A - Improvements in surface apparatus for effecting transfer of heat between fluids - Google Patents

Abstract

653,570. Tubular and plate heat ex. changers; tubular elements. HEAT EXCHANGERS, Ltd., and STEVENS, M. J. May 21, 1948, No. 13812. [Class 64(iii)] A heat exchanger, e.g. for heating air for combustion by means of combustion gases, comprises units each having parallel paths 5 for an internal fluid and when stacked (in Fig. 1, three stacks, each of three units, as shown in Fig. 4, are arranged in a casing 1 open ended for the flow of external fluid) the units leave room for the external fluid to flow between adjacent units because end junction portions 6, although wider at the end 7 where they connect with the path ends 4, are deeper at the narrow end 8 where they contact one another and connect to headers 2, 3. The junction portions 6 are of a cross sectional area equal to the sum of the cross sectional areas of the internal fluid paths 5 in each unit. The fluid paths in each unit are formed by tubes which are deformed at the ends 4 to a rectangular section but may be formed by two superimposed corrugated sheets joined at their crests. The tubes in each unit have their rectangular ends in one row but for the greater part of their lengths may be in two parallel planes in staggered formation. Each junction portion 6 may be formed as shown in Fig. 12 with surfaces gradually curving from one end to the other and the upper and lower surfaces meeting at a sharp edge 13. If the units are used in a cylindrical casing, e.g. surrounding a turbine shaft or compressor, the units may be made arcuate or cylindrical in cross section. In a modification, to form flow and return paths, with the inlets and outlets side by side in the same plane at one end, the fluid paths form a U or the junction portions 6 at the other end are joined by an arcuate duct. The junction portions 6 connect to headers 2, 3 which may consist of superimposed annular sections secured by tie bolts. Headers may also conduct the external fluid to the spaces between the internal fluid paths 5 in which case they are paired with the headers to the internal fluid paths, Fig. 18, the pairs having curved contacting surfaces so that the apertures 30 at the junction portion end are side by side and the apertures 31 at the other end are superimposed.