| 摘要 |
PURPOSE:To obviate generation of buckling load in heat transfer tubes in the stage of welding the heat transfer tubes and tube plates successively in a multitubular heat exchanger by welding the heat transfer tubes to be welded later while holding the tubes cooled. CONSTITUTION:A heat transfer tube 2 to be welded is cooled by using a cooler 4 in such a way that the overall length of the tube 2 is made shorter by the length corresponding to DELTAlw than the overall mounting length of a heat transfer tube 1 where the amt. of shrinkage of the tube 2 by welding is defined as DELTAlw, and in this state, the tube is welded to a tube plate 3. More specifically, one end of the tube 2 is welded to the lower tube plate 3; thereafter, the coller 4 is interted into said tube and while the tube is held cooled, said tube is welded to the upper tube plate 3. In the multitubular heat exchanger constituted by repeating the above-mentioned operations, the tube 2 after the cooler 4 is removed restores the ordinary temp. and recovers the same length as the overall length of the tube 1, therefore the generation of buckling load between the plural tubes 1 and the plates 3 is obviated. |
