摘要 |
A method and apparatus for automatically assembling hairpin tubes in the tube receiving holes of a fin pack unit. Pre-assembled fin pack units are serially moved from one station to the next to receive hairpin tubes, to have bells formed in the open ends of the laced hairpin tubes, to have expansion tools inserted upwardly through the open ends of the hairpin tubes to expand the walls of the tubes outwardly into contact against the fin plates and tube sheets with sufficient force to lock the tubes into the unit, and to have return bends interconnect the bell-like seats of adjacent hairpin tubes and thus complete the heat exchanger flow circuit. |