EXPANDING MANDREL, EXPANDING METHOD AND EXPANDING APPARATUS USING THE EXPANDING MANDREL AND HEAT EXCHANGER WITH HEAT EXCHANGING TUBES EXPANDED BY THE EXPANDING METHOD

摘要

An expanding mandrel (10) used mainly for expandingheat exchanging tubes (21) of a cross fin coil (20) of anair conditioning machine, so as to connect them to fins ofthe cross fin coil. The expanding mandrel hasflexibility, comprising a plurality of mandrel pieces (11)which are bandably connected in a row, with an expandinghead (13) disposed at the leading end. By an expandingmethod and an expanding apparatus both using the mandrel(10), the mandrel (10) is wound on the winding drum (41);is fed from the winding drum (41) so as to be inserted intothe heat exchanging tube (21) of the cross fin coil so asto be expanded at the time of tube expansion; and isretracted from the heat exchanging tube (21), aftercompletion of the expanding, so as to be wound on thewinding drum (41). This provides a decreased size of theapparatus and allows even an expansion of a heat exchangingtube which has been bend-processed.