Patent ID: 7886440
Filing Date: 2011-02-15
Classification: B21C,B21D,F28D,F28F,Y10T

Abstract:
1. A manufacture method for an inner-fin tube which has a tube member and an inner fin member, the tube member being constructed from a first band-shaped plate member which is bent so that the tube member defines therein a passage with a flat cross section perpendicular to a longitudinal direction of the tube member and is joined at a side of one end of a major axis direction of the flat cross section, the inner fin member being constructed from a second band-shaped plate material and arranged in the tube member, the manufacture method comprising: continuously forming the tube member from the first band-shaped plate material in such a manner that the major axis direction of the flat cross section extends vertically and an open end is disposed at a lower end of the tube member; continuously transferring the inner fin member constructed of the second band-shaped plate material in such a manner that the inner fin member is arranged apart from the tube member in a horizontal direction by a predetermined distance and in parallel to the tube member formed in the continuously forming step, the inner fin member being arranged at a lower side of the tube member; twisting the inner fin member transferred in the continuously transferring step in order to alter a transfer direction of the inner fin member at least two separate times, so that the inner fin member faces the tube member and then the inner fin member faces the major axis direction of the flat cross section of the tube member, the cross section of the inner fin member being perpendicular to the transfer direction of the inner fin member; and inserting the inner fin member into the tube member through the open end of the lower end of the tube member which is at the halfway stage of the tube forming process, the transfer direction of the inner fin member having been changed during the twisting step.