HEAT-EXCHANGER MADE OF ALUMINUM ALLOY

PROBLEM TO BE SOLVED: To prevent the brazing properties of each plate member and heating tube element and the pressure resistance of each heating tube element from lowering by providing each plate member with a central recess having a flange-like outer circumferential fringe and making a plurality of holes at a part of the outer circumferential fringe which is located at the upper half part of the heating tube element at the time of brazing. SOLUTION: A recess 9 is made in the center of a plate member 7a and a flange-like outer circumferential fringe 24 is provided at the outer circumference of the recess 9. A plurality of holes 25 are made at a part of the outer circumferential fringe 24 which is located at the upper half part of each heating tube element at the time of brazing. The holes 25 are made asymmetrically at a part of the outer circumferential fringe 24 of the plate member 7a which is located at the upper half part of each heating tube element at the time of brazing. When a heating tube element is constituted by superposing a pair of plate members 7a having same shape, the holes 25 made at the outer circumferential fringe 24 of both plate members 7a do not match each other. According to the arrangement, pressure resistance of each heating tube element can be enhanced while reducing the weight and the reliability, durability, and the like, can also be enhanced.