Heat exchanger having plural tubes connected to header tanks by brazing

Abstract

A heat exchanger such as a condenser for use in an automobile air-conditioning system is composed of a pair of header tanks, plural tubes connecting both header tanks, and fins made of a thin aluminum plate disposed between the tubes. Those components are all connected to one another by brazing to form a unitary body of the heat exchanger. A solder material for bonding the tubes and the header tanks is attached onto the inner surface of both header tanks to prevent the solder material from dispersing into the thin fins in the brazing process. Thus, the thin aluminum fins are protected against erosion due to the solder dispersed therein.

What is claimed is:  
     
         1 . A heat exchanger comprising: 
 a pair of cylindrical header tanks, each having a fluid passage therein;    a plurality of tubes, each connected between the pair of header tanks to establish fluid communication between the fluid passages in the pair of header tanks; and    a plurality of fins connected between the tubes in heat-conductive relation, wherein:    a solder material is attached onto the inner surface of each header tanks; and    the tubes are connected to header tanks by the solder material in a brazing process.    
     
     
         2 . The heat exchanger as in    claim 1   , wherein: 
 the header tanks, the tubes and the fins are made of aluminum.    
     
     
         3 . The heat exchanger as in    claim 1   , wherein: 
 a sacrificial corrosion layer is further attached onto the outer surface of the header tanks.    
     
     
         4 . A method of manufacturing a heat exchanger having a pair of cylindrical header tanks, a plurality of tubes connected between the pair of header tanks and a plurality of fins connected between the tubes, the method comprising: 
 attaching a solder material for connecting the tubes to the header tanks onto the inner surface of the header tanks;    assembling the header tanks, the tubes and the fins together to form an assembled unit; and    brazing the assembled unit in a furnace to form a unitary body of the heat exchanger.    
     
     
         5 . The method of manufacturing a heat exchanger as in    claim 4   , wherein: 
 the method further includes a step of coating a flux material necessary for brazing on the outer surface of the tubes, the coating step being performed before the assembling step.    
     
     
         6 . A heat exchanger for use in a refrigerating cycle in an automotive air-conditioner system as a condenser for condensing over-heated refrigerant supplied thereto, the heat exchanger comprising: 
 a first header tank made of aluminum having an elongate inner space;    a second header tank made of aluminum having an elongate inner space;    a plurality of tubes made of aluminum, each connected between the pair of header tanks, so that the refrigerant introduced into the inner space of the first header tank is distributed to the plurality of tubes and flows into the inner space of the second header tank; and    a plurality of corrugated fins, each connected between the tubes in heat-conductive relation, wherein:    a solder layer for connecting the tubes to the header tanks by brazing is clad on the inner surface of the header tanks.