Laminated heat exchanger

A laminated heat exchanger comprising a plurality of flat, hollow members arranged in a left-right direction in a laminated condition, each of the flat, hollow members comprising two vertically elongated metal plates having perimetric edge portions joined together, a bulging refrigerant flow tube portion being formed between the two metal plates, a bulging tank formation portion being formed continuously with each of opposite ends of the refrigerant flow tube portion, the tank formation portions of adjacent flat, hollow members being joined together, clearances between the refrigerant flow tube portions of adjacent flat, hollow members serving as air-passing clearances, a refrigerant outlet being formed in an outside wall of the tank formation portion of an endmost flat, hollow member located at one end in the left-right direction, an outlet header being fixed to an outer surface of the outside wall of the tank formation portion of the endmost flat, hollow member, the outlet header comprising a tubular body extending in a front-rear direction and having opposite end openings and a closing member for closing one of the end openings of the body, a refrigerant passage hole communicating with the refrigerant outlet being formed in a side wall of the body of the outlet header, and an outlet pipe having a circular cross section being connected to an open end portion of the body of the outlet header, wherein:

• the refrigerant outlet is formed into a circular shape, and an inside diameter of the refrigerant outlet is 90% to 110% that of the outlet pipe excluding a worked distal end portion;
• the body of the outlet header comprises a first portion which is located on a side toward the closing member and in which the refrigerant passage hole is formed, a second portion which is the open end portion thereof and has a short, cylindrical shape and into which an end portion of the outlet pipe is inserted, and a third portion which integrally connects the first portion and the second portion;
• the first portion has a flat wall portion along the outer surface of the outside wall of the tank formation portion of the endmost flat, hollow member, and two fragmentary, cylindrical wall portions which are continuous with respective upper and lower edges of the flat wall portion via respective connection portions;
• a radius of curvature of an inner circumferential surface of the fragmentary, cylindrical wall portion is 35% to 50% a height of an interior space of the first portion;
• and
• an equivalent diameter of a cross section of the interior space of the first portion is 90% to 110% an inside diameter of the outlet pipe excluding the worked distal end portion.