Method of securing tubes between tube sheets

摘要

A method of securing tubes between tube sheets of a heat exchanger, with the tube sheets being interconnected via a housing. The tubes and/or the tube sheets of are made of a steel that has to be annealed after a welding process. To be able to provide a stress-free connection between the tubes and the tube sheets, and to enable simple repair of the tubes, the length of at least one end of each tube is extended by welding thereto a tubular piece that is made of a material that can be welded without subsequent thermal treatment being required. Sleeves that extend the length of the holes in the tube sheet are welded onto the outer surface of at least one of the tube sheets. At least the free end of each sleeve is made of a material that can be welded without subsequent thermal treatment being required. One end of each tube, if such end is not provided with a tubular extension, is welded onto a tube sheet. A final thermal treatment is carried out after all welding steps that require a subsequent thermal treatment are concluded. The tubes are indirectly connected to those tube sheets that are provided with sleeves by welding the free ends of the tubular extensions of the tubes to the sleeves.