Heat exchange – Tubular structure
Reexamination Certificate
2000-09-25
2002-10-29
Bennett, Henry (Department: 3743)
Heat exchange
Tubular structure
C165S183000, C165S133000
Reexamination Certificate
active
06470964
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a heat exchanger tube preferably used for a heat exchanger tube for a cooling medium or the like which constitutes a condenser of an air conditioner or a refrigerator.
This application is based on Japanese Patent Application No. 2000-13400, the contents of which are incorporated herein by reference.
2. Discussion of Background
In a cooling device such as an air conditioner or a refrigerator or the like, a cooling medium (fluid) of Freon or the like is first compressed to form a high temperature and high pressure gas and is then liquefied by cooling the gas with a condenser. In the condenser is incorporated a heat exchanger tube through which a cooling medium flows, and a high temperature and high pressure gaseous cooling medium is gradually cooled by heat dissipation while passing through the tube so that it is condensed into a liquid. As this kind of heat exchanger tubes, a heat exchanger tube shown in
FIG. 10
or the like has been known. A tube body
7
is constituted by a solder material-cladded band-shaped metallic plate member
1
being folded or bent with a fold
2
in a direction of its extension, connecting end portions
5
,
5
, which are mutually brought into contact with end portions of one wall portion
3
and the other wall portion
4
folded and extended in the same direction, are formed and are welded thereto, and a cooling medium passage
6
is formed between these wall portions.
Further, the curvature radius of the fold
2
is smaller than the width of the wall portion
3
or
4
, and the distance between the wall portions
3
and
4
is smaller than the width of the wall portion
3
or
4
. This shape is defined to reduce the time required for heat dissipation by decreasing the distance from the center of the tube body
7
to the wall portion.
The thus formed interior defines a cooling medium passage
6
. A plurality of bulging wall portions
8
,
8
. . . bulging in a bowl shape toward a direction of the opposite wall portions are formed on both opposite wall portions
3
and
4
of the tube body
7
in which the inner surface and the outer surface are defined as the heat entrance and exit surfaces for the cooling medium, and bulging leading ends of the bulging wall portions
8
,
8
. . . are defined as connecting portions
9
,
9
. . . The connecting portions
9
,
9
. . . are brought into contact with opposite bulging wall portions in a plane and are welded by soldering. A cooling medium that flows in the interior of the tube is caused to generate a turbulent flow by these bulging wall portions
8
,
8
. . . and is uniformly agitated within the tube body so that the temperature distribution of a fluid in a plane vertical to the flow is made uniform. Further, the opposite wall portions
3
and
4
are connected to each other by the plurality of welded bulging wall portions
8
,
8
. . . and are supported against a pressure applied to the wall portions
3
and
4
of the flat tube body
7
when a high pressure cooling medium flows in the tube, thereby enhancing the pressure resistance of the tube body
7
.
However, the above-mentioned conventional heat exchanger tube has the following problems.
Since the tube body is formed by folding a band-shaped metallic plate member with a fold, it tends to be deformed by an effect of the spring back at the fold, that is, the restoration of the bent portions, in such a manner that the opposite wall portions are separated from each other.
On the other hand, the opposite cooling medium agitating bulging portions bulging in bowl shapes are soldered in a plane at the connecting portions brought into contact with each other. However, when an oxide film formed on the surface of a solder material has been separated for soldering with flux, the bulging portion has a structure making discharge of the separated oxide film from the outer periphery of the surface-shaped connecting portion difficult. Thus, it is actually difficult to solder at the center of the connecting portion.
Therefore, in addition to the circumstances of difficult soldering, when a force which separates the opposite wall portions by the spring back is applied to the tube body, firm welding is not performed at the connecting portion between the bulging wall portion leading ends. As a result, the tube body has no support against the pressure of the cooling medium, whereby the pressure resistance of the tube body deteriorates.
SUMMARY OF THE INVENTION
The present invention was made in consideration of the above-mentioned circumstances. The object of the present invention is to provide a heat exchanger tube having an improved soldering process and high pressure resistance by forming a structure which easily discharges an oxide film separated with flux, and prevents the deformation of the tube body due to the spring back effect.
A first aspect of the invention relates to a heat exchanger tube having the tube body whose interior is defined as a passage of a fluid and whose inner and outer surfaces are defined as heat entrance and exit surfaces of the fluid and is characterized in that a bulging wall portion bulging toward a direction of opposite wall portions is formed on one or both of the opposite wall portions of said tube body, the bulging leading ends of said bulging wall portions are defined as connecting portions linearly protruding and said connecting portions are linearly brought into contact with the opposite wall portions and are fixed thereto.
By providing such a configuration, a soldering material oxide separated with flux at the connecting portion of the leading end of the bulging wall portion flows out of a linear connecting portion whereby soldering is improved and the opposite wall portions are firmly soldered without occurrence of a weld failure.
A second aspect of the invention relates to a heat exchanger tube, and is characterized in that it provides a first bulging wall portion bulging in a bowl shape in a direction of wall portions opposite to said bulging wall portion, with a plurality of said first bulging wall portions being formed on said tube body.
By providing such a configuration, the opposite wall portions are connected to each other at a plurality of positions by a plurality of first bulging wall portions. Further, a fluid flowing in the interior of the tube generates a turbulence flow with the plurality of first bulging wall portions and is uniformly agitated in the tube body.
A third aspect of the invention relates to a heat exchanger tube, and is characterized in that a plurality of protrusions with triangular sections protruding linearly in the direction of the extension of the tube body are formed on the inner surface of said tube body in such a manner that they are adjacent to each other, said protrusions being defined as said connecting portions.
By providing such a configuration, positions which are linearly soldered are increased at the connecting portions of the leading ends of the first bulging wall portions where opposite wall portions are connected to each other. Thus, the opposite wall portions are firmly connected to each other.
Further, since the surface area of the inner surface of the tube body defined as the heat entrance or exit surface is increased, a contact area with the fluid is increased.
A fourth aspect of the invention relates to a heat exchanger tube, and is characterized in that it provides a second bulging wall portion including a first extending portion extending toward the direction of wall portions opposite from one reference position of the wall portion to serve as said bulging wall portion, a return portion which is folded back from said first extending portion to the direction of said reference position and a second extending portion which is folded back from the return portion to said one reference position of the wall portion.
By providing such a configuration the folded portion of the second bulging wall portion and the opposite wall portions are linearly brought into contact with each other in a direction
Inoue Masashi
Nakado Koji
Bennett Henry
Duong Tho V
Mitsubishi Heavy Industries Ltd.
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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