Tube for heat exchanger

Details Tube for heat exchanger Tube for heat exchanger

1999-09-29

2001-02-27

Lazarus, Ira S. (Department: 3743)

Heat exchange

Tubular structure

C029S890049, C029S890053, C029S890054, C138S168000

Reexamination Certificate

active

06192977

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a tube for a heat exchanger and a process for manufacture of such a tube, and more specifically to a so-called “folded tube” of a type suitable for furnace brazing.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 1,937,343 discloses a motor vehicle radiator having tubes of the folded type. The tubes of this prior art document have a seam at an end portion of the cross-section of the tube, the seam being formed by folding the two edge portions of the very thin metal of which the tube is constructed, each upon itself, followed by interlocking the folded portions flat against the inner surfaces of the tube wall.
The transverse curvature of the seam gives a good lock and assists in soldering the seam.
In prior art tubes, a close fit between the inner and outer edge portions of the seam will prevent adequate flux penetration for successful brazing of the inner portion of the seam. This is particularly true for so-called “NOCOLOK” (RTM) brazing. Where the fit is too tight, flux must be drawn in from the outside or from the open ends of the tube. Neither of these brazing methods is reliable.
It is accordingly an object of the present invention to provide an improved structure and an improved method of manufacture.
SUMMARY OF THE INVENTION
According to a first aspect of the present invention there is provided a method of forming a tube for a heat exchanger, said tube having a cross-section having two opposing ends and two opposing sides, one of said ends having a double wall, said method comprising: forming an inner wall of said double wall, said inner wall extending in one direction to an extremity region and in a second direction opposite to said one direction, to one of said opposing sides via a transition region;
forming an outer wall of said double wall, said outer wall extending from the other of said opposing sides to an extremity;
wherein said transition region accommodates said extremity of said outer wall and said extremity region of said inner wall is formed to deviate away from said outer wall.
Preferably said method further comprises causing flux to penetrate between said extremity region of said inner wall and said outer wall and between said extremity of said outer wall and said transition region.
Advantageously said method further comprises brazing said inner and outer walls together.
In an alternative embodiment of the invention, the brazing step may comprise NOCOLOK (RTM) brazing.
According to a second aspect of the present invention there is provided a tube for a heat exchanger having a cross-section comprising two opposed side walls and two opposed ends, said opposed ends comprising curved portions, the outer surface of said ends being substantially mirror symmetrical, one of said ends having a double wall comprising an inner wall and an outer wall, one of said side walls extending to form the outer wall and the other of said side walls extending to form the inner wall wherein each of said outer and said inner walls has a respective extremity, the inner wall, in a region overlaid by the extremity of the outer wall, being offset inwardly to accommodate said extremity of the outer wall, and the extremity of the inner wall deviating away from the outer wall.
Advantageously said tube further comprises brazed joints extending between portions of said inner and outer walls.
Advantageously said opposed ends each comprise a substantially planar portion whereby said tube is oblong in cross-section.
Conveniently said side walls are substantially parallel.


REFERENCES:
patent: 824492 (1906-06-01), Livingston
patent: 2912749 (1959-11-01), Bauernfeind et al.
patent: 3053511 (1962-09-01), Godfrey
patent: 4470452 (1984-09-01), Rhodes
patent: 4570700 (1986-02-01), Ohara et al.
patent: 5185925 (1993-02-01), Ryan et al.
patent: 5439050 (1995-08-01), Waterman et al.
patent: 5441105 (1995-08-01), Brummett et al.
patent: 5692300 (1997-12-01), Conn et al.
patent: 5956846 (1999-09-01), Ross et al.
patent: 6014988 (2000-01-01), Gagnon et al.

Affiliated with

Also associated with

Rating

Tube for heat exchanger does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Tube for heat exchanger, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tube for heat exchanger will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2562966