Heat exchange – Tubular structure
Reexamination Certificate
2000-02-24
2004-10-05
Ciric, Ljiljana (Department: 3753)
Heat exchange
Tubular structure
C029S890053, C029S890054, C165S170000
Reexamination Certificate
active
06799630
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a tube for a heat exchanger, which is produced by forming beads on a brazing sheet for composing the tube and brazing the tops of the beads with the opposing portions in a tube part.
BACKGROUND ART
A conventionally known heat exchanger is configured by connecting a plurality of tubes for exchanging the heat of a medium so to communicate with header pipes for distributing and collecting the medium.
The tube used for such a type of heat exchanger is produced by forming a brazing sheet into the shape of a tube and brazing required points of the tube. The brazing sheet is formed by rolling, pressing or the like.
The brazing sheet has the surface of a plate matrix clad with a brazing material. Brazing is generally carried out by assembling tubes, header pipes and other members into one body and thermally treating the assembly. In other words, the required parts of the tube and other required parts of the heat exchanger are brazed by a single operation of heat treatment.
And, this tube is provided at appropriate intervals with beads for dividing passages for a medium. Specifically, the beads are formed by bending the brazing sheet so to have recessed portions, and the tops of the beads are brazed with the opposed portions within the tube part in order to improve the pressure resistance and heat-exchanging property of the tube.
For example,
FIG. 9
is a transverse sectional view showing an example of forming the brazing sheet.
FIGS. 10 and 11
are transverse sectional views each showing the top of a bead formed on the brazing sheet and the opposed portion within the tube part.
A brazing sheet B is provided with a plurality of beads
31
,
31
at appropriate intervals and joint sections
32
,
32
at both ends of the brazing sheet in its breadth direction. The brazing sheet B is folded along a folding section
33
at the center in the breadth direction so to join the joint sections
32
,
32
mutually (see FIG.
9
).
The formed body of the brazing sheet B is integrally assembled with other members and thermally treated so to braze the joint sections
32
,
32
mutually.
When the brazing sheet B is folded, each of the beads
31
has its top
31
a
contacted to an opposed portion within a tube part
30
(see FIG.
10
). The top
31
a
of the bead
31
is brazed with the opposed portion within the tube part
30
when the joint sections
32
,
32
are mutually brazed (see FIG.
11
).
FIGS. 10 and 11
show that a brazing material
36
melts from the surface of a matrix
35
of the brazing sheet B to enter a space between the top
31
a
of the bead
31
and the opposed portion within the tube.
Arrows t in
FIGS. 10 and 11
indicate a predetermined thickness of the tube
3
. In other words, the matrix
35
of the brazing sheet B is determined so to have a predetermined dimension when the brazing sheet B is folded.
In order to secure the aforesaid satisfactory pressure resistance and heat-exchanging property for the tube for a heat exchanger, it is necessary to securely and firmly braze the tops of the beads with the opposed portions within the tube part.
The brazing between the tops of the beads and the opposed portions within the tube part is quite delicate to securely have the brazing material between them. Therefore, there was often a problem that brazing was defective at some positions in the tube.
For example, even when the tops of the beads are brought into contact with the opposed portions within the tube part in the stage of forming the brazing sheet into the tube part, the brazing material melts from the surface of the matrix
35
of the brazing sheet while brazing, and a space s corresponding to a thickness of the brazing material layer is formed between the tops
31
a
of the beads
31
and the opposed portions within the tube part as shown in FIG.
12
. The space s formed between both sections of the matrix
35
makes it difficult to secure the brazing material needed for brazing and causes the degradation of a brazing property.
In view of the problems described above, it is an object of the present invention to provide a tube for a heat exchanger, which can have tops of beads brazed securely and firmly with opposed portions within a tube part, and a method for manufacturing the same.
DISCLOSURE OF THE INVENTION
According to the invention there is provided a tube for a heat exchanger having beads formed on a brazing sheet for configuring the tube and the tops of the beads brazed with opposed portions within a tube part, wherein the tops of the beads are crushed against the opposed portions within the tube.
According to the tube for a heat exchanger of the present invention, the tops of the beads are crushed in the opposed portions within the tube part, so that the tops of the beads can be brazed securely and firmly with the opposed portions within the tube part by virtue of the brazed portions.
REFERENCES:
patent: 1177320 (1916-03-01), Grabawsky
patent: 3750709 (1973-08-01), French
patent: 5186250 (1993-02-01), Ouchi et al.
patent: 5271151 (1993-12-01), Wallis
patent: 5560425 (1996-10-01), Sugawara et al.
patent: 5579837 (1996-12-01), Yu et al.
patent: 5697433 (1997-12-01), Kato
patent: 5799397 (1998-09-01), Yasuda et al.
patent: 5826646 (1998-10-01), Bae et al.
patent: 932335 (1955-08-01), None
patent: 404086489 (1992-03-01), None
patent: 405045082 (1993-02-01), None
patent: 11-30493 (1999-02-01), None
patent: 11-63872 (1999-03-01), None
patent: 89432 (1937-06-01), None
Akiyama Shoji
Haiya Sadao
Kato Soichi
Kurihara Shin
Sakurada Muneo
Ciric Ljiljana
Takeuchi & Takeuchi
Zexel Corporation
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