HEAT-EXCHANGER REPAIR

There are two ways to repair heater tubes in tubular heat exchangers, partial replacement of tubes and a technique called sleeving. In the f ormer case, the defective tube section is cut out removed, and replace d by a new section butt welded to the old piece of tube which remained in place. in the sleeving technique, a tube sleeve is slid into the d efective tube and, after expansion, welded to the original tube. In th is case, the welding technique employed is not laser welding, as is of ten maintained in the literature, but TIG pulsation welding. The resul ts of preliminary tests and the qualification of both processes are ou tlined in the article; an account is given also of the replacement of the tube sections when repairing condensate coolers.