Heat exchanger

A heat exchanger comprising a plurality of fluid channel members arranged one above another in parallel at a spacing and each composed of a first plate and a second plate, the first plate having a fluid passing hole at each of opposite lateral ends thereof and a channel portion extending over the entire length thereof between the end holes for forming a fluid channel, the second plate having a fluid passing hole at each of opposite lateral ends thereof, the plates being joined with a recessed surface of the channel portion of the first plate opposed to the second plate to form the fluid channel member;

• and annular header members each interposed between each pair of adjacent fluid channel members at each of opposite lateral ends of the heat exchanger, each the header members having upper and lower end faces one of which comprises a flat portion to be fitted to a peripheral edge portion of the second plate defining the end hole thereof, the other end face comprising a flat portion to be fitted to a flat portion of an edge of the first plate defining the end hole thereof and a recessed portion to be fitted to a protuberant end face of the channel portion of the first plate, one of the upper and lower end faces of each of the header members at each of the opposite lateral ends of the exchanger being joined to the hole-defining peripheral edge portion of the second plate opposed thereto, the other end face being joined to a peripheral edge portion of the first plate opposed thereto and defining an opening formed by the end hole of the first plate and an open end of the channel portion thereof for communication with the header member to form a header at each of the opposite lateral ends.