Heat exchanger and method of joining heat exchanger pipe

A method of joining a pipe to a heat exchanger, the heat exchanger including

• a body portion including a first plate and a second plate, each of the first and second plates having a mating surface, wherein a coolant flow passage is formed by brazing the first plate and the second plate by use of a first brazing filler metal covering the mating surface of at least one of the first plate and the second plate;
• a first groove portion provided in the first plate, wherein the first groove portion includes an inner surface;
• a second groove portion provided in the second plate, wherein the second groove portion includes an inner surface;
• and
• a pipe brazed between the first groove portion and second groove portion by use of a second brazing filler metal covering the inner surface of the first and the inner surface of the second groove portions, the method comprising:
• covering, with the second brazing filler metal, at least one of inner surfaces of a pair of first flanges and inner surfaces of a pair of second flanges, wherein
• the pair of first flanges is provided contiguously with the first groove portion in a direction approximately orthogonal to a laminated direction of the first and second plates and an axial direction of the pipe and
• the pair of second flanges is provided contiguously with the second groove portion in a direction approximately orthogonal to the laminated direction of the first and second plates and the axial direction of the pipe;
• placing the pipe between the first groove portion and second groove portion with the second brazing filler metal interposed between the pipe and each of the first and second groove portions;
• holding the first and second flanges by jigs with the second brazing filler metal interposed between each of the first and second pairs of flanges;
• and
• brazing by melting the second brazing filler metal to liquefy the second brazing filler, filling a gap between the first and second groove portions and the pipe with the liquefied second brazing filler metal, and cooling the second brazing filler metal,
• wherein the second brazing filler metal is pushed into the gap by a holding force given by the jigs.