Flat tube for heat exchanger

Abstract

A flat tube having a nearly B-like shape or the like in cross section, which has one or more partitions therein, and is coated with a brazing metal on the outer surface thereof, is provided. In the top portion of the turned-up portion constituting the partition, there are formed many slits, in order to provide the conditions that satisfy both of the brazing performance and an increase of working accuracy of the flat tube, which slits allow the brazing metal to enter up to the top portion of the turned-up portion, wherein the length “c” of the slit is 2 mm to 15 mm; the distance “e” between the edges of the neighboring slits is 3 mm to 10 mm; and “e/c” is 0.6 or more.

1 . A flat tube for heat exchanger, comprising: 
 a pair of flat face portions parallelly opposed to each other and a pair of curved portions connected to both ends of the flat face portions formed with a strip-shaped metal plate bent in the width direction thereof to form into a flat cylindrical shape,    wherein the strip-shaped metal plate is coated with a brazing metal on one surface thereof, and is bent so that the brazing metal is positioned at the outer surface side of the cylindrical shape;    in the central position in the width direction of one of the flat face portions, a turned-up portion is bent up to the opposed flat surface side, and the top portion of the turned-up portion abuts on the inner surface of the opposed surface side to form a partition within the tube;    many slits for allowing the brazing metal to enter therethrough are formed intermittently being separated away from each other in the top portion in the longitudinal direction thereof,    wherein the length “c” of the slit is 2 mm to 15 mm;    the distance “e” between the edges of the neighboring slits is 3 mm to 10 mm; and    “e/c” is 0.6 or more.    
   
   
       2 . The flat tube for heat exchanger according to  claim 1 , wherein the thickness of the strip-shaped metal plate is 0.15 mm to 0.6 mm.