TUBE EXPANDING MANDREL, TUBE EXPANDING METHOD AND TUBE EXPANDING APPARATUS USING TUBE EXPANDING MANDREL, AND HEAT EXCHANGER HAVING HEAT EXCHANGING TUBE WHICH IS SUBJECTED TO TUBE EXPANDING BY TUBE EXPANDING METHOD.

摘要

A tube expanding method and a tube expanding apparatus use a tube expanding mandrel for expanding a heat exchanging tube (21) mainly in a cross fin coil (20) of an air conditioner for connection with fins, said tube expanding mandrel being a flexible mandrel (10) comprising a number of mandrel pieces (11) bendably connected to one another and a tube expanding head (13) mounted at a tip end thereof, said mandrel (10) being adapted to be wound on a winding drum (41) and to be paid out from the winding drum (41) and inserted into the heat exchanging tube (21) being expanded in a cross fin coil for expanding the same at the time of tube expanding, said mandrel (10) being adapted to be pulled out from the heat exchanging tube (21) after tube expanding and wound on the winding drum (41). It is possible to make the apparatus small-sized and expand even a heat exchanging tube which has been subjected to bending. <IMAGE>