METHOD FOR BRAZING A HEAT EXCHANGER FOLDED TUBE WHILE APPLYING A FLUX NEAR A CONTACT ZONE OF THE WALLS, RESULTING TUBE

摘要

#CMT# #/CMT# The brazing of a folded tube for a heat exchanger consists of placing a first tube part (20) in contact with a contact surface of a second tube part (22) and brazing the two tube parts at the level of the contact zone using a brazing deposit and a brazing flux to form the brazed liaison. The brazing flux (32) is applied on the contact surface of the second tube part, prior to the brazing operation, in controlled conditions at a distance close to the contact zone. #CMT# : #/CMT# An independent claim is also included for a heat exchanger tube assembled by this method. #CMT#USE : #/CMT# Used for the brazing of folded tubes for a heat exchanger, notably for motor vehicles. #CMT#ADVANTAGE : #/CMT# Allows the controlled application of the brazing flux prior to brazing leading to reduced consumption of brazing flux and an improved quality of brazing. It can be used to produce different types of heat exchanger tubes, which can be produced with a single sheet or with several sheets. It is also possible to form tubes with several adjacent channels delimited by walls made up of folds formed in the material of the external wall of the tube. #CMT#DESCRIPTION OF DRAWINGS : #/CMT# The drawing is a transverse cross-section of a heat exchanger tube with a general section in the form of a B after folding and before brazing according to the invention. 10 : Heat exchanger tube 12, 14 : Larger surfaces of tube 16, 18 : Smaller connecting surfaces in form of a U 20 : First tube part 22 : Second tube part 30 : Channels for circulation of fluid 32 : Brazing flux #CMT#METALLURGY : #/CMT# Preferred Process: The brazing flux is applied in the form of a paste under a controlled atmosphere and at a density of between 2 and 120 g/m 2>(claimed). The heat exchanger tube is formed from at least one metal sheet, advantageously of aluminum (claimed). The brazing deposit is carried out by a plating operation (claimed). The brazing is carried out under a controlled atmosphere with a base of nitrogen (claimed).