Heat exchange – With coated – roughened or polished surface
Reexamination Certificate
2000-09-08
2002-01-22
Flanigan, Allen (Department: 3743)
Heat exchange
With coated, roughened or polished surface
C165S184000, C029S890049, C072S197000
Reexamination Certificate
active
06340050
ABSTRACT:
TECHNICAL FIELD
This invention relates to an internally-grooved heat exchanger tube for use in a heat exchanger of a refrigerating machine and an air conditioning machine or the like, and a metal strip machining roll for machining a metal strip for such an internally-grooved heat exchanger tube by means of rolling.
More specifically, the present invention relates to an internally-grooved heat exchanger tube structured such that the internal surface of a metal tube is divided into a plurality of continuous areas parallel to the axial direction of the tube, and fine parallel fins different in fin pattern (i.e., a fin lead angle to the axial direction of the tube, a fin vertical angle and a fin pitch or the like) are respectively formed in the adjacent areas, and a metal strip machining roll suitably used for machining a metal strip for such a heat exchanger tube by means of rolling.
BACKGROUND ART
In Japanese Patent Laid-open Nos. 3-13796 and 4-158193, for instance, there is provided an internally-grooved heat exchanger tube structured such that the internal surface of a metal tube is divided into a plurality of continuous areas parallel to the axial direction of the tube, and a large number of fins different in fin pattern are respectively formed in the adjacent areas.
A description will now be given of the internally-grooved heat exchanger tube disclosed in the above Japanese Patent Laid-open No. 3-13796 with reference to FIG.
19
.
The internal surface of a metal tube
1
is divided into a plurality of continuous areas W
1
, W
2
, W
1
, W
2
parallel to the axial direction L of the tube, and a large number of fine parallel fins
10
,
11
respectively having the reversed lead angles &thgr;, &thgr;′ to the axial direction L of the tube are formed in the adjacent areas W
1
, W
2
.
In manufacture of the internally-grooved heat exchanger tube shown in
FIG. 19
, a belt-like metal strip
1
a
of a certain width made of copper or copper alloy, for instance, needs to be rolled in the manner of passing such a metal strip through a gap between a machining roll
3
shown in
FIG. 20 and a
support roll (not shown) having a flat surface pressed against the machining roll
3
.
The machining roll
3
is equivalent to a roll of a predetermined length formed by combining a plurality of discshaped roll pieces
3
a
,
3
b
,
3
a
,
3
b
of a predetermined thickness together in layers parallel to the axial direction, and a large number of fine parallel grooves
30
,
31
respectively having the reversed lead angles &thgr;1, &thgr;1′ to the axial direction are formed densely on the outer surfaces of the adjacent roll pieces
3
a
,
3
b.
Thus, the large number of fins
10
,
11
described above are respectively formed on one surface of the rolled metal strip
1
a
shown in
FIG. 19
in the manner of transferring the large number of grooves
30
,
31
of the machining rolls
3
a
,
3
b
to one surface of the rolled metal strip.
Subsequently, the metal strip
1
a
is formed in a tubular shape by the steps of setting the metal strip in an electro-uniting device (not shown) with the fin-formed surface turned to the inside, then rounding the metal strip in the cross direction in the manner of passing the metal strip through a gap between each pair of forming rolls (not shown) installed in the electro-uniting device in multiple stages, and welding the butted ends in the cross direction together.
Further, the tubular molding is formed into the metal tube
1
as shown in
FIG. 19
by the steps of removing a weld bead portion from the tubular molding, and subjecting the tubular molding to sinking by a predetermined drawing device to reduce the diameter of the tubular molding to a predetermined size.
According to the heat exchanger tube shown in
FIG. 19
, in the case of letting the refrigerant flow toward an upper portion in the tube in
FIG. 19
, for instance, the refrigerant flows toward each boundary portion a′ between the adjacent areas W
1
, W
2
while being guided by the fins
10
,
11
, and the collision between the flows of refrigerant occurs in each boundary portion a′ to form a turbulent flow, so that this turbulent flow makes it possible to prevent the temperature gradient from being caused in the refrigerant, resulting in the improvement in tube heat transfer performance.
In the case of incorporating the heat exchanger tube of the prior art described above into a heat exchanger, this heat exchanger tube accelerates the formation of the turbulent flow of refrigerant in the boundary portions a′ to permit the improvement in heat transfer performance.
However, since the boundary portions a′ run parallel to the axial direction L of the tube, and the interference between the turbulent flows respectively formed in the boundary portions a′ before and behind the flowing direction of refrigerant occurs to thereby cancel the effects of turbulent flow each other, the sufficient heat transfer performance could not be improved.
Further, while the heat exchanger tube of the prior art may eliminate the temperature gradient parallel to the axial direction L of the tube, the temperature gradient is easily caused parallel to the peripheral direction by this heat exchanger tube, and as a result, there is a problem in that it is not possible to sufficiently improve the heat transfer performance.
An object of the present invention is to provide an internally-grooved heat exchanger tube, which makes it possible to greatly improve the tube heat transfer performance by restraining the turbulent flows of refrigerant flowing in the axial direction of the tube from interfering with each other in a boundary portion between the adjacent areas W
1
, W
2
, while sequentially guiding a turbulent-flow formed portion of the refrigerant toward the inner peripheral side of the tube.
Another object of the present invention is to provide a metal strip machining roll, which may smoothly machine a metal strip for the internally-grooved heat exchanger tube capable of achieving the above object.
DISCLOSURE OF THE INVENTION
For solving the above problems, an internally-grooved heat exchanger tube according to the present invention has the following structure.
That is, an internally-grooved heat exchanger tube in the first mode according to the present invention is characterized in that the internal surface of a metal tube
1
is divided into a plurality of continuous areas W
1
, W
2
parallel to the axial direction L of the tube, a large number of fine parallel fins
10
,
11
are respectively formed in the adjacent areas W
1
, W
2
, the fins
10
in one area W
1
out of the adjacent areas and the fins
11
in the other area W
2
are different in at least one selected among lead angle &thgr;, &thgr;′ to the axial direction L of the tube, fin vertical angle &agr;, &agr;′ and fin pitch p, p′, and a boundary portion a between at least one area W
1
and the other area W
2
adjacent to the one area W
1
is formed in the state of meandering to the axial direction L of the metal tube
1
.
An internally-grooved heat exchanger tube in the second mode according to the present invention is characterized in that, in the internally-grooved heat exchanger tube in the first mode, the fins
10
formed in one area W
1
out of the adjacent areas and the fins
11
formed in the other area W
2
have the reversed lead angles &thgr;, &thgr;′ to the axial direction L of the tube.
An internally-grooved heat exchanger tube in the third mode according to the present invention is characterized in that, in the internally-grooved heat exchanger tube in the second mode, the lead angle &thgr; of each fin
10
in one area W
1
out of the adjacent areas ranges from 15° to 50°, while the lead angle &thgr;′ of each fin
11
in the other area W
2
ranges from −15° to −50°.
An internally-grooved heat exchanger tube in the fourth mode according to the present invention is characterized in that, in the internally-grooved heat exchanger tube in the first or second mode, the boundary portion
Hashizume Toshiaki
Mori Yasutoshi
Nakamizo Kenzi
Yamamoto Kouzi
Flanigan Allen
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
The Furakawa Electric Co., Ltd.
LandOfFree
Internally grooved heat exchanger pipe and metal bar working... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Internally grooved heat exchanger pipe and metal bar working..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Internally grooved heat exchanger pipe and metal bar working... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2817324