Patent ID: 7448440
Filing Date: 2008-11-11
Classification: F28D,F28F

Abstract:
1. A heat exchanger comprising upper and lower header tanks disposed apart from each other, and a plurality of heat exchange tubes disposed in parallel between the two header tanks and having opposite end portions connected to the respective header tanks, wherein each of the head tanks is configured such that an outside plate, an inside plate, and an intermediate plate intervening between the outside and inside plates are brazed together in layers; each of the outside plates of the upper and lower header tanks has a plurality of outwardly bulging portions each extending in the left-right direction and having an opening closed by the intermediate plate; the inside plate has a plurality of tube insertion holes in the form of through-holes formed in a region corresponding to the outwardly bulging portions of the outside plate and spaced apart from one another along the left-right direction; the intermediate plate has a plurality of communication holes in the form of through-holes so as to allow the respective tube insertion holes of the inside plate to communicate with the interiors of the corresponding outwardly bulging portions of the outside plate; opposite end portions of the heat exchange tubes are inserted through the respective tube insertion holes of the inside plates of the two header tanks and are brazed to the inside plates; at least one outwardly bulging portion of each of the upper and lower header tanks serves a refrigerant-passage outwardly bulging portion within which refrigerant flows in the longitudinal direction; the refrigerant-passage outwardly bulging portion of the upper header tank serves as an inflow-side refrigerant-passage outwardly bulging portion whose one end portion communicates with a refrigerant inlet formed in the upper header tank; the communication holes of the intermediate plates communicating with the refrigerant-passage outwardly bulging portions of the upper and lower header tanks are connected by means of communication portions each formed between adjacent communication holes of the intermediate plates; and the communication holes communicating with the refrigerant-passage outwardly bulging portions and the communication portions connecting these communication holes cooperate to form refrigerant passages in the intermediate plates of the upper and lower header tanks, the passages communicating with the interiors of the corresponding refrigerant-passage outwardly bulging portions and causing the refrigerant to flow in the left-right direction, wherein of all the communication portions which form the refrigerant passage of the intermediate plate communicating with the inflow-side refrigerant-passage outwardly bulging portion of the upper header tank, a plurality of narrow communication portions on the upstream side with respect to the flow direction of the refrigerant have a width, as measured in the front-rear direction, smaller than that of the remaining communication portions; and the relation 0.25≦A/B≦0.35 is satisfied, where A represents the number of the narrow communication portions, and B represents the total number of the communication holes which form the refrigerant passage and wherein the relation 0.6≦WA/WB≦0.8 is satisfied, where WA represents the width, as measured in the front-rear direction, of the narrow communication portions of all the communication portions which form the refrigerant passage of the intermediate plate communicating with the inflow-side refrigerant-passage outwardly bulging portion of the upper header tank, and WB represents the width of the remaining wide communication portions, as measured in the front-rear direction.