Abstract: A plate type heat exchanger of the continuous plate type includes a housing having opposed open ends and a thermal transfer core disposed within the housing which is formed of a continuous sheet of heat conductive material folded upon itself on fold regions in opposite directions alternately to define a plurality of substantially parallel, mutually spaced sheet portions which extend through the housing, substantially each sheet portion thereby being located between first and second adjacent sheet portions with the fold regions being located contiguous with opposed sides of the housing.

Abstract: A heat exchanger for transmitting thermal energy from one moving fluid to another of the type having a casing housing a thermal transfer core, the core including a folded sheet of heat conductive material defining adjacent fluid flow passages, the individual fold sections of the sheet having a multiplicity of pairs of dimples formed therein, each dimple pair including a raised dimple and an adjacent depressed dimple, the height of each dimple being substantially equal to one-half the width of the fluid flow passages. The dimple arrangement provides a relatively low pressure drop for the fluids passing through the fluid flow passages.

Abstract: A heat exchanger core includes a communicating set of metallic tubular elements, preferably aluminum, for carrying a primary fluid and a matrix of rounded metallic elements. The matrix elements are metallurgically bonded to one another and to the tubular elements. This arrangement of the matrix creates a multiplicity of communicating interstices which serve as passageways for the secondary fluid. The surface of the rounded elements constitutes the major area exposed to the secondary fluid flow. The rounded elements are metallurgically bonded by preferably a brazing technique. Relatively small particles of low melting temperature alloy, preferably aluminum, are dispersed throughout a stacked arrangement of relatively larger rounded elements, preferably of aluminum of a higher melting temperature. In one brazing method, an assembly of tubes, large rounded elements and smaller particles are brazed in a vacuum brazing oven. At the temperature of the oven, the smaller particles melt but the larger elements do not.