ES338713A1 - Improvements in heat exchangers - Google Patents

Abstract

A heat exchanger intended for use in a steam turbine installation, comprises an outer tubular casing through which extends a tube bundle consisting of a multiplicity of continuous metal tubes having an external diameter of less than 0À15 ins., said tubes being hermetically sealed at each end of the casing into a header plate positioned across the casing end section and also to spaced-apart partitions within the casing to form at least four separate chambers, whereby fluid introduced through suitable openings can be brought into heat exchange relationship with fluid in the tubes separately from the fluid introduced to the other chambers. In the form shown a collar 80 of polygonal outer section is placed around the requisite section of each tube 12 allowing the tubes to be contiguous with one another when clamped by a surrounding ring 84 (Figs. 2-4). Alternatively the tube ends are expanded to a hexagonal outline (90, Fig. 5) so that when the expanded sections are contiguous the tubes are spaced apart by the required distance. In another arrangement the header plate or partition comprises a stack of identically similar laminations (Fig. 6) apertured to receive the tubes. In another form (Fig. 8), the header or partition is produced by a matrix of particulate, woven or unwoven, stranded or fibrous material. In Figs. 9-13, (Figs. 10, 13, not shown) the header/partition is formed of a plurality of recessed or apertured members each forming a part of the area of the header/partition, e.g. strips (102), and the opposite faces of which include a plurality of spaced apart semicylindrical recesses 109, so that when the strips are stacked, corresponding recesses are aligned to define bores for receiving the ends of the tubes, the strip assembly defining a circular periphery for insertion in the casing. Similarly, instead of individual strips, the strips can be spirally wound (Fig. 11) so that the bores for receiving the tube ends are defined by the recesses in one layer and the contiguous surface of an adjacent layer. In another embodiment (Figs. 15-17) the tube ends are held tightly together in mutual contact by means of a suitable clamping arrangement, pressure then being exerted on the ends of the tubes to splay out the regions of the tubes between the clamping means, suitable spacers then being inserted. In all embodiments so described, each assembly is finally brazed, so that all the interstices become filled with the brazing material to form a solid and hermetically sealed assembly. The arrangement of the various chambers in the heat exchanger described (Figs. 1a, 1b, 1c).