Patent ID: 7165326

Claim:
A process for fabricating a heat exchanger, comprising: preparing a hairpin tube by bending a pipe having no welded seams and a plurality of plate fins each having two holes spaced apart; inserting two straight tube portions of the hairpin tube through the respective holes of the plate fins to thereby arrange the plate fins in parallel into a predetermined number of unfixed fin groups spaced apart on the straight tube portions longitudinally thereof by a length permitting bending of the straight tube portions; enlarging the hairpin tube to fixedly position the plate fins across the two straight tube portions to obtain a finned hairpin tube having a dividable fin group for forming second fin groups and a first fin group; dividing the plate fins of the dividable fin group into portions fixed to one of the straight tube portions and portions fixed to the other straight tube portion to form the second fin groups; and outwardly bending the two straight tube portions of the finned hairpin tube forward and rearward respectively, wherein the plate fins of the dividable fin group for forming the second fin groups each comprise two fin forming portions and connecting portions dividably joining the two fin forming portions.