Abstract: The invention contemplates an improved sandwich-type core construction for a heat exchanger, featuring light weight without sacrifice of the strength needed for handling elevated pressures. Passages of one set are interleaved with those of another set, using spaced parallel heat-transfer plates. Elongate parallel spacers extending in one direction establish, with their adjacent plates, flow passages of one system, while elongate parallel spacers extending in a different direction establish flow passage of a second system, between paired plates of the first system. The perimeter of the core at ends of at least one of the system passages establishes solid continuous seating for such system headers. Substantial weight saving, without sacrifice of strength, is achieved by depressed excavation of spacer material in regions thereof not involved in header-seating accommodation.

Abstract: A heat exchanger comprises a stack of spaced plates such that elongate plane-parallel fluid-conduit systems are established between adjacent pairs of plates, the plane-parallel conduit systems being in two sets, with the conduit system of one set being interposed between two conduit systems of the other set. Between adjacent plates, a conduit system is closed along its two laterally opposite edges, by rail-like spacers between the involved adjacent plates. The conduit system of at least one set comprises corrugated structures taking the form of extruded sections and having ridges which are connected to the lateral-edge closures of the involved conduit system.