Method for manufacturong heat exchanger

Abstract

Low melting point metal such as Zn is sprayed onto a flat surface ( 3 a ) of an aluminum flat tube ( 3 ) to form a sprayed metal coating ( 15 ) thereon inmediately after extrusion of the flat tube. Inmediately thereafter, a brazing foil ( 11 ) is integrally adhered onto the sprayed metal coating ( 15 ). The obtained flat tube ( 3 ) with the brazing foil is combined with a corrugated fin ( 4 ) to form a temporary assembly. Then, the temporary assembly is heated at a predetermined temperature to braze the tube ( 3 ) and the fin ( 4 ) to thereby form a heat exchanger core. The low melting point metal may be sprayed on both the flat surface ( 3 a ) of the flat tube and the surface of the brazing foil ( 11 ). Thus, it becomes possible to obtain a lightweight thin fin and to decrease material costs.

1 . (Amended) A method for manufacturing a heat exchanger, comprising the steps of: 
 extruding an aluminum material into a flat tube which constitutes a heat exchanging tube;    integrally adhering a brazing foil via a sprayed metal coating to a flat surface of said flat tube immediately after extrusion of said flat tube, said sprayed metal coating having a melting point lower than a melting point of said brazing foil;    combining said flat tube having said brazing foil with a fin; and    heating said flat tube having said brazing foil and said fin to melt said brazing foil to thereby join said fin to said flat tube.    
     
     
         2 . (Amended) A method for manufacturing a heat exchanger, comprising the steps of: 
 extruding an aluminum material into a flat tube which constitutes a heat exchanging tube;    supplying a brazing foil to a flat surface of said flat tube immediately after extrusion of said flat tube;    spraying metal onto a surface of said brazing foil at the time of supplying said brazing foil to said flat surface of said flat tube to form a sprayed metal coating, said metal having a melting point lower than a melting point of said brazing foil;    pressing said brazing foil on said flat surface of said flat tube to thereby adhere said brazing foil to said flat tube via said sprayed metal coating;    combining said flat tube having said brazing foil with a fin; and    heating said flat tube having said brazing foil and said fin to melt said brazing foil to thereby join said flat tube to said fin.    
     
     
         3 . (Amended) A method for manufacturing a heat exchanger, comprising the steps of: 
 extruding an aluminum material into a flat tube which constitutes a heat exchanging tube;    supplying a brazing foil to a flat surface of said flat tube immediately after extrusion of said flat tube;    spraying metal onto a surface of said brazing foil and said flat surface of said flat tube at the time of supplying said brazing foil to said flat surface of said flat tube to form a sprayed metal coating, said metal having a melting point lower than a melting point of said brazing foil;    pressing said brazing foil on said flat surface of said flat tube to thereby adhere said brazing foil to said flat tube via said sprayed metal coatings;    combining said flat tube having said brazing foil with a fin; and    heating said flat tube having said brazing foil and said fin to melt said brazing foil to thereby join said flat tube to said fin.    
     
     
         4 . (Amended) A method for manufacturing a heat exchanger, comprising the steps of: 
 extruding an aluminum material into a flat tube which constitutes a. heat exchanging tube;    supplying a brazing foil to a flat surface of said flat tube immediately after extrusion of said flat tube;    spraying metal onto said flat surface of said flat tube at the time of supplying said brazing foil to said flat surface of said flat tube to form a sprayed metal coating, said metal having a melting point lower than a melting point of said brazing foil;    pressing said brazing foil on said flat surface of said flat tube to thereby adhere said brazing foil to said flat tube via said sprayed metal coating;    combining said flat tube having said brazing foil with a fin; and    heating said flat tube having said brazing foil and said fin to melt said brazing foil to thereby join said flat tube to said fin.    
     
     
         5 . (Amended) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein Zn is used as said metal to be sprayed.  
     
     
         6 . (Amended) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein an amount of said metal to be sprayed falls within the range of from 3 g m 2  to 50 g/m 2 .  
     
     
         7 . (Amended) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein an amount of said metal to be sprayed falls within the range of from 5 g/m 2  to 15 g/m 2 .  
     
     
         8 . (Amended) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein a width of said brazing foil is one fourth or more of a width of said flat tube.  
     
     
         9 . (Amended) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein a width of said brazing foil is half or more of a width of said flat tube.  
     
     
         10 . (Amended) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein a thickness of said brazing foil falls within the range of from 2 to 100 μm.  
     
     
         11 . (Amended) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein a thickness of said brazing foil falls within the range of from 2 to 40 μm.  
     
     
         12 . (Added) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein said brazing foil comprises: 
 5 to 20 wt % of Si;  
 0 to 5 wt % of Zn;  
 0 to 0.5 wt % of In; and  
 the balance Al and impurities.  
 
     
     
         13 . (Added) The method for manufacturing a heat exchanger as recited in any of  claims 1  to  4 , wherein an average diameter of grains constituting said brazing foil is 20 μm or less.