Patent ID: 7854255

Claim:
A heat exchanger comprising a core body in which a strip-shaped metal plate is turned up and bent in a fanfold manner with turned-up end edges alternately formed at one end and the other end of a rectangular flat face portion and flat first flow passages and second flow passages are provided alternately in the thickness direction of the metal plate, each of the first flow passages of the core body being blocked by each comb tooth of a pair of comb-state members at both end positions of said turned-up end edge, and a fin being set within said second flow passages so as to constitute a core, the outer periphery of the core body being fitted with a cylindrical casing so as to block the adjacent turned-up end edges, a first fluid being guided to each of the first flow passages by a pair of ports on the outer face of said casing, while a second fluid being guided from one of cylindrical openings of said casing to the other opening through each of the second flow passages, wherein said casing comprises a channel-state material covering three faces of the outer periphery of said core body and a lid material blocking the opening of the channel-state material, said channel-state material being formed of a high heat-resistant and corrosion-resistant material, said lid material being formed of a material having lower heat-resistance and corrosion-resistance than the channel-state material; the casing having a pair of longitudinal ends and header portions extending outward from each of the ends of the casing, the longitudinal ends each being provided with a header end lid that blocks its end of the casing, each header end lid being formed of a high heat-resistant and corrosion-resistant material; each header end lid having an extension portion covering an inner surface of each header portion; in said core body, a starting end and a terminating end of the turning-up of said strip-shaped metal plate are both located at said turned-up end edge on one side; a fitting edge portion with a section turned up in the U-shape conforming to the plate thickness of said channel-state material is provided at the starting end and the terminating end; and the end edge of said opening of the channel-state material is fitted with the fitting edge portion and the both are brazed and fixed.