Patent ID: 6926069

Claim:
A method for manufacturing a double-walled heat exchange tube with a leak detection channel; the method comprising the steps of: providing inner and outer tubes, with the outer tube having an inner surface and the inner tube having an outer surface, the inner tube being manufactured of a softer material than the material of the outer tube; providing a surface profiling on at least one of the inner surface of the outer tube and the outer surface of the inner tube; selectively providing at least one of the inner surface and said outer surface with a layer of soldering material; expanding said inner tube such that the outer surface of the inner tube is in intimate contact with the inner surface of the outer tube and the surface profiling forms at least one leak detection channel between the two tubes; expanding the inner tube such that the outer tube is expanded as well; causing the layer of soldering material between the inner tube and the outer tube to be melted; wherein the expansion of the outer tube is effected such that the molten solder is forced out between the inner tube and the outer tube into the leak detection channel.