A method of welding a pipe to the wall of a pipe housing seat

摘要

The invention relates to a method of welding the outer surface (5a) of a pipe (5) and the wall (4) of a cylindrical seat (5) for housing the pipe (5), the method providing, amongst its successive operative steps, for the step of providing vacuum and sealing a substantially tubular space (S) between the wall (4) and the surface (5a), followed by the step of the combined internal pressurization and heating of the pipe (5). The desired weld is thus formed and the accumulation in the space (S) of air which, once the pipe expands radially as a result of the pressurization and the heating, would be compressed within it and would oppose the aforesaid expansion, is prevented. Owing to its simplicity and flexibility, the method of the invention can be used either for welding one pipe at a time, or for welding a plurality of pipes simultaneously, as occurs during the formation of heat-exchanger elements. In the latter case, the spaces (S) of the various pipes (5) are sealed with the aid of a metal foil which is wrapped around the exchange element to form a covering thereof.