Abstract: An improved method for forming a heat exchanger core from a single elongated sheet of metal which is stamped to define longitudinally spaced corrugated sections and then is pleat folded between the stamped sections to define first and second groups of alternating fluid passages for indirect heat transfer between two fluids. During stamping of each corrugated section, edges of such section are clamped in place to define precise exterior dimensions and the corrugations are formed by stretching the metal to conform with a die. The stamped corrugations are shaped with triangular end reinforcements to control the location of the bends as the sheet is folded into the final shape of the core. Edges of the sections defining each passage in the first group are sealed together to prevent the fluids from leaking around such edges.

Abstract: An improved heat exchanger is constructed with a core formed from a single elongated sheet of metal which is stamped to define longitudinally spaced corrugated sections and then is pleat folded between the stamped sections to define first and second groups of alternating fluid passages for indirect heat transfer between two fluids. During stamping of each corrugated section, edges of such section are clamped in place to define precise exterior dimensions and the corrugations are formed by stretching the metal to conform with a die. The stamped corrugations are shaped with triangular end reinforcements to control the location of the bends as the sheet is folded into the final shape of the core. Edges of the sections defining each passage in the first group are sealed together to prevent the fluids from leaking around such edges.