Heat exchanger

A heat exchanger comprising a pair of header tanks arranged as spaced apart from each other, and a plurality of heat exchange tubes arranged in parallel between the pair of header tanks and each having opposite ends joined to the respective header tanks,

• each of the header tanks comprising a header forming plate, a tube connecting plate and an intermediate plate interposed between the two plates, the header forming plate, the tube connecting plate and intermediate plate being arranged in superposed layers and brazed to one another, the header forming plate being provided with at least one outward bulging portion extending longitudinally thereof and having an opening closed with the intermediate plate, the tube connecting plate being provided at a portion thereof corresponding to the outward bulging portion with a plurality of tube insertion holes arranged longitudinally of the tube connecting plate at a spacing and extending through the thickness thereof, the intermediate plate having communication holes extending through the thickness thereof for causing the respective tube insertion holes of the tube connecting plate to communicate with interior of the outward bulging portion of the header forming plate therethrough, the heat exchange tubes having their opposite ends inserted into the respective tube insertion holes of the tube connecting plates of the header tanks and brazed to the tube connecting plates, at least one of all the outward bulging portions serving as a refrigerant passing outward bulging portion for causing a refrigerant to flow through the interior thereof longitudinally thereof, the intermediate plate communication holes in communication with the refrigerant passing outward bulging portion being held in communication by communication portions formed in the intermediate plate, the communication portions and the communication holes thereby held in communication providing a refrigerant passageway for causing the refrigerant to flow therethrough longitudinally of the refrigerant passing outward bulging portion, the communication portions being adjusted in width to alter the cross sectional area of the refrigerant passageway along the lengthwise direction of the passageway.