GB1188981A - Methods for Making Heat Exchangers. - Google Patents

Abstract

1,188,981. Injection moulding. MARSTON RADIATORS Ltd. 7 Feb., 1968 [1 Feb., 1967], No. 4826/67. Heading B5A. [Also in Divisions F2 and F4] In the manufacture of a heat exchanger core tubes of metal, e.g. brass, are passed through apertures in a first plate layer also of metal, and project beyond this plate layer so that they may be engaged within cavities of a mould element, whereby the mould element, first plate layer and tubes define a mould chamber into which is injected synthetic plastics material, e.g. polysulphone, polyphenylene oxide or polycarbonate with or without reinforcing glass or other fibres, to form a second plate layer. This second layer acts both to secure the tubes to the first plate layer and also as a foundation to which a plastics header tank (not shown) may be secured. In the embodiment of Fig. 1, pins 9 on the mould element 6 engage within the tubes 1 to prevent their collapse, and keying of the injected plastic second layer 5 with the tubes is ensured by providing grooves 4 in the latter. Blocks 10 are located below the first plate layer 2 before moulding. In the embodiment of Fig. 2, the mould element 15 has slidable plungers 17 in place of the pins 9, the plungers being initially retracted, while the mould element 15 is located on the tube ends, and then operated as a tool to expand the ends of the tubes against the sides of counterbores 16, whereby the second plate layer 13 is retained after moulding by the expanded tube ends. Additional keying of the plastics layer may be effected in either embodiment by providing holes in the first plate layer which are filled with plastic during moulding, the holes being counterbored on the lower side of the first plate layer (as at 23, Fig. 3, not shown) to provide a positive key formation. The tubes may be a loose fit in the apertures in the first plate layer to provide additional keying.