Folded tube for heat exchanger, and heat exchanger including such tubes

Abstract

The invention relates to a tube for a heat exchanger, consisting of a metal strip having an inner face and an outer face, this strip having two extremities which are folded locally towards the inner face of the tube so as to form two borders ( 28, 30 ) placed one beside the other. Passages ( 38 ) are formed in at least one of the extremities of the metal strip for introduction of a brazing flux. These passages ( 38 ) can be formed in the two extremities of the metal strip, and offset with respect to one another. The passages extend over a distance greater than the height of the borders ( 28, 30 ) in such a way as to form an inlet ( 40 ) for the brazing flux.

1 . Tube for a heat exchanger, consisting of a metal strip having an inner face and an outer face, this strip having two extremities which are folded locally towards the inner face of the tube so as to form two borders ( 28 ,  30 ) placed one beside the other, characterized in that passages ( 38 ) are formed in at least one of the extremities of the metal strip for introduction of a brazing flux.  
     
     
         2 . Tube according to  claim 1 , characterized in that passages ( 38 ) are formed in the two extremities of the metal strip.  
     
     
         3 . Tube according to  claim 2 , characterized in that the passages ( 38 ) of one extremity are offset with respect to the passages ( 38 ) of the other extremity of the metal strip.  
     
     
         4 . Tube according to  claim 1 , characterized in that the passages ( 38 ) are produced by knurling of the extremities of the metal strip.  
     
     
         5 . Tube according to  claim 4 , characterized in that the metal strip is folded by passing through a series of successive rollers, and in that the knurling is carried out before passing through the forming rollers.  
     
     
         6 . Tube according to  claim 1 , characterized in that the passage ( 38 ) are produced substantially perpendicularly to the extremities of the metal strip.  
     
     
         7 . Tube according to  claim 1 , characterized in that the passages ( 38 ) are produced obliquely with respect to the extremities of the metal strip.  
     
     
         8 . Tube according to  claim 1 , characterized in that the passages extend over a distance greater than the height of the borders ( 28 ) and ( 30 ) in such a way as to form an inlet ( 40 ) for the brazing flux.  
     
     
         9 . Tube according to  claim 1 , characterized in that the outer face of the metal strip is covered with a plating of brazing alloy.  
     
     
         10 . Heat exchanger, especially for a motor vehicle, comprising a bank of tubes ( 16 ) alternating with cooling spacers ( 15 ), characterized in that the tubes are in accordance with  claim 1 .  
     
     
         11 . Method of manufacturing a tube for a heat exchanger, as defined in  claim 1 , by folding and brazing of a metal strip, this strip including an inner face and an outer face, characterized in that a brazing flux is deposited solely on the outer face of the tube.  
     
     
         12 . Manufacturing method according to  claim 11 , characterized in that the brazing flux is deposited on the outer face of the metal strip by spraying.