U.S. patent application number 10/525220 was filed with the patent office on 2006-06-15 for heat exchanger, method for manufacturing heat exchanger, tube connecting structure for heat exchanger header tank, gas cooler using supercritical refrigerant, and refrigerant system.
This patent application is currently assigned to SHOWA DENKO K.K.. Invention is credited to Noboru Ogasawara, Etsuo Shinmura, Koichiro Take.
Application Number | 20060124289 10/525220 |
Document ID | / |
Family ID | 32023574 |
Filed Date | 2006-06-15 |
United States Patent
Application |
20060124289 |
Kind Code |
A1 |
Shinmura; Etsuo ; et
al. |
June 15, 2006 |
Heat exchanger, method for manufacturing heat exchanger, tube
connecting structure for heat exchanger header tank, gas cooler
using supercritical refrigerant, and refrigerant system
Abstract
A heat exchanger according to the present invention includes a
pair of header tanks 10a and 10b and a plurality of heat exchanging
tubes 30 disposed between the header tanks and arranged in
parallel. The header tank 10 and 10b is provided with partitioning
walls 15 integrally formed to the header tank along the
longitudinal direction. The inside space of the header tank is
divided by the partitioning walls 15 into tank partions 11 to 014.
Refrigerant turning communication apertures 17 are formed in the
predetermined partitioning wall 15. The refrigerant passages 35 of
the heat exchanging tube 30 are grouped so as to correspond to each
tank portion of the header tank 10a and 10b to thereby form a
plurality of passes P1 to P4. The refrigerant introduced into the
first tank portion 11 of one of the header tanks 10a passes through
each passes P1 to P4 in this order from the rear side toward the
front side, and then introduced into the fourth tank portion 14 of
the other of the header tanks 10b. According to this heat
exchanger, enough pressure resistance and heat exchanging
performance can be obained.
Inventors: |
Shinmura; Etsuo; (Tochigi,
JP) ; Take; Koichiro; (Tochigi, JP) ;
Ogasawara; Noboru; (Tochigi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SHOWA DENKO K.K.
13-9 Shiba Daimon 1-chome Minato-ku
Tokyo
JP
105-8515
|
Family ID: |
32023574 |
Appl. No.: |
10/525220 |
Filed: |
August 21, 2003 |
PCT Filed: |
August 21, 2003 |
PCT NO: |
PCT/JP03/10620 |
371 Date: |
January 13, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60407945 |
Sep 5, 2002 |
|
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|
Current U.S.
Class: |
165/176 ;
165/174 |
Current CPC
Class: |
F28D 1/05391 20130101;
F28D 2021/0073 20130101; F28F 1/025 20130101; F28F 9/0214 20130101;
F28F 9/0202 20130101 |
Class at
Publication: |
165/176 ;
165/174 |
International
Class: |
F28F 9/02 20060101
F28F009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 21, 2002 |
JP |
2002 240927 |
Claims
1. A heat exchanger, comprising: a pair of header tanks; and a
plurality of heat exchanging tubes disposed between said pair of
header tanks and arranged in parallel in a header tank longitudinal
direction, wherein each of said header tanks is provided with one
or more partitioning walls integrally formed in each of said header
tanks and extended in the header tank longitudinal direction,
whereby a plurality of tank portions divided by said one or more
partitioning walls and extended in the header tank longitudinal
direction are formed and arranged in parallel in a header tank
widthwise direction, wherein a refrigerant turning communication
aperture for communicating adjacent tank portions is formed in a
prescribed partitioning wall, wherein each of said heat exchanging
tubes has a flat configuration having a width dimension larger than
a height dimension, and is provided with a plurality of refrigerant
passages extended in a tube longitudinal direction and arranged in
parallel in a tube widthwise direction, wherein both ends of each
of said heat exchanging tubes are communicated with said pair of
header tanks so that said refrigerant passages of each of said heat
exchanging tubes are grouped in the tube widthwise direction in
accordance with each tank portion of said header tanks, to thereby
form a plurality of passes arranged in parallel in the tube
widthwise direction, and wherein refrigerant introduced into a
first tank portion of one of said header tanks is introduced into a
first tank portion of the other of said header tanks via a first
pass, then the refrigerant is introduced into a second tank portion
of the other of said header tanks via said refrigerant turning
communication aperture, and thereafter the refrigerant is
introduced into a second tank portion of said one of said header
tanks via a second pass.
2. The heat exchanger as recited in claim 1, wherein each of said
header tanks is an integrally formed article formed by extrusion
processing or drawing processing.
3. The heat exchanger as recited in claim 1, wherein said heat
exchanging tube is an integrally formed article formed by extrusion
processing or drawing processing.
4. The heat exchanger as recited in claim 1, wherein a plurality of
tube insertion apertures communicating with said tank portions are
provided at an inner side surface of each of said header tanks at
certain intervals in the header tank longitudinal direction, and
wherein refrigerant passages at end portions of said heat
exchanging tubes are communicated with corresponding tube insertion
apertures.
5. The heat exchanger as recited in claim 4, wherein end portions
of each of said heat exchanging tubes are provided with one or more
cutout portions corresponding to said one or more partitioning
walls, and said end portions of each of said heat exchanging tubes
are inserted into said tube insertion apertures with said one or
more partitioning walls fitted in said one or more cutout
portions.
6. The heat exchanger as recited in claim 5, wherein one or more
regions of each of said heat exchanging tubes corresponding to said
one or more cutout portions are formed to be one or more
non-passage areas in which no refrigerant passage exists, and
wherein regions of each of said heat exchanging tubes not
corresponding to said one or more cutout portions are formed to be
passage areas in which said refrigerant passages exist.
7. The heat exchanger as recited in claim 1, wherein said
refrigerant turning communication aperture formed in said
partitioning wall of the other of said header tanks is configured
by a cut aperture formed in an inside surface of the other of said
header tanks.
8. The heat exchanger as recited in claim 1, wherein each of said
header tanks is provided with a joining plate joined to an inner
side surface thereof, wherein a plurality of tube insertion
apertures are provided in said joining plate at certain intervals
in a joining plate longitudinal direction, and wherein end portions
of each of said heat exchanging tubes are inserted into
corresponding tube insertion apertures to be communicated with said
header tanks.
9. The heat exchanger as recited in claim 1, wherein CO.sub.2 is
used as the refrigerant.
10. A method for manufacturing a heat exchanger, comprising:
preparing a pair of header tanks, wherein each of said header tanks
is provided with one or more partitioning walls integrally formed
in each of said header tanks and extended in a header tank
longitudinal direction, whereby a plurality of tank portions
divided by said one or more partitioning walls and extended in the
header tank longitudinal direction are formed so as to be arranged
in parallel in a header tank widthwise direction, wherein a
refrigerant turning communication aperture for communicating
adjacent tank portions is formed in predetermined partitioning
walls; preparing a plurality of heat exchanging tubes, wherein each
of said heat exchanging tubes has a flat configuration having a
width dimension larger than a height dimension, and is provided
with a plurality of refrigerant passages extended in a tube
longitudinal direction and arranged in parallel in a tube widthwise
direction; and forming a plurality of passes arranged in parallel
in the tube widthwise direction by communicating both ends of each
of said heat exchanging tubes with said pair of header tanks so
that said refrigerant passages of each heat exchanging tubes are
grouped into said plurality of passes in the tube widthwise
direction in accordance with each of said tank portions of said
header tank, whereby refrigerant introduced into a first tank
portion of one of said header tanks is introduced into a first tank
portion of the other of said header tanks via a first pass, then
the refrigerant is introduced into a second tank portion of the
other of said header tanks via said refrigerant turning
communication aperture, and thereafter the refrigerant is
introduced into a second tank portion of said one of said header
tanks via a second pass.
11. The method for manufacturing a heat exchanger as recited in
claim 10, wherein at least one of said header tanks is provided, at
its inner surface side, with a plurality of tube insertion
apertures for communicating end portions of said heat exchanging
tubes and said refrigerant turning communication aperture, and
wherein said tube insertion apertures and said refrigerant turning
communication aperture are formed simultaneously by cutting
processing.
12. A heat exchanger, comprising: a pair of header tanks; and a
plurality of heat exchanging tubes disposed between said pair of
header tanks and arranged in a header tank longitudinal direction,
wherein each of said header tanks is provided with three
partitioning walls integrally formed in each of header tanks and
extended in the header tank longitudinal direction, whereby a first
tank portion to a fourth tank portion divided by said partitioning
walls and extended in the header tank longitudinal direction are
formed so as to be arranged in parallel in a header tank widthwise
direction, wherein a refrigerant turning communication aperture for
communicating adjacent tank portions is formed in a partitioning
wall partitioning the second tank portion and the third tank
portion of said one of said header tanks, a partitioning wall
partitioning the first tank portion and the second tank portion of
the other of said header tanks and a partitioning wall partitioning
the third tank portion and the fourth tank portion of the other of
said header tanks, wherein each of said heat exchanging tubes has a
flat configuration having a width dimension larger than a height
dimension, and is provided with a plurality of refrigerant passages
extended in a tube longitudinal direction and arranged in parallel
in a tube widthwise direction, wherein both ends of each of said
heat exchanging tubes are communicated with said pair of header
tanks so that said refrigerant passages of each of said heat
exchanging tubes are grouped in the tube widthwise direction in
accordance with each tank portion of said header tanks, to thereby
form a first to fourth passes arranged in parallel in the tube
widthwise direction, and wherein refrigerant introduced into the
first tank portion of one of said header tanks passes through the
first to fourth passes in turn and then introduced into the fourth
tank portion of said one of said header tanks.
13. A tube connecting structure for a header tank of a heat
exchanger comprising a pair of header tanks and a plurality of heat
exchanging tubes disposed between said pair of header tanks and
arranged in a header tank longitudinal direction, wherein each of
said header tanks is provided with one or more partitioning walls
integrally formed in each of header tanks and extended in the
header tank longitudinal direction, whereby a plurality of tank
portions divided by said partitioning walls and extended in the
header tank longitudinal direction are formed so as to be arranged
in parallel in a header tank widthwise direction, wherein tube
insertion apertures communicating with said tank portions are
formed in one side surface of each of said header tanks, wherein
each of said heat exchanging tubes has a flat configuration having
a width dimension larger than a height dimension, and is provided
with a plurality of refrigerant passages extending in a tube
longitudinal direction and arranged in parallel in a tube widthwise
direction, wherein both ends of each of said heat exchanging tubes
are communicated with said pair of header tanks so that said
refrigerant passages of each of said heat exchanging tubes are
grouped in the tube widthwise direction in accordance with each
tank portion of said header tanks, to thereby form a plurality of
passes arranged in parallel in the tube widthwise direction, and
wherein refrigerant passes through each of said grouped refrigerant
passages independently.
14. The tube connecting structure as recited in claim 13, wherein
end portions of said heat exchanging tubes are provided with one or
more cutout portions corresponding to said one or more partitioning
walls, and said end portions of said heat exchanging tubes are
inserted into said tube insertion apertures with said one or more
partitioning walls fitted in said one or more cutout portions.
15. The tube connecting structure as recited in claim 14, wherein
one or more regions of each of said heat exchanging tubes
corresponding to said one or more cutout portions are formed to be
one or more non-passage areas in which no refrigerant passage
exists, and wherein regions of each of said heat exchanging tubes
not corresponding to said one or more cutout portions are formed to
be passage areas in which said refrigerant passages exist.
16. A refrigerant system having a refrigeration cycle in which
refrigerant compressed by a compressor is cooled by a gas cooler,
decompressed by a decompressor, then heated while passing through a
cooling device and then returned to said compressor, wherein said
gas cooler is configured by a heat exchanger comprising a pair of
header tanks and a plurality of heat exchanging tubes disposed
between said pair of header tanks and arranged in a header tank
longitudinal direction, wherein each of said header tanks is
provided with one or more partitioning walls integrally formed in
each of said header tanks and extended in the header tank
longitudinal direction, whereby a plurality of tank portions
divided by said one or more partitioning walls and extended in the
header tank longitudinal direction are formed so as to be arranged
in parallel in a header tank widthwise direction, wherein a
refrigerant turning communication aperture for communicating
adjacent tank portions is formed in a prescribed partitioning wall,
wherein each of said heat exchanging tubes has a flat configuration
having a width dimension larger than a height dimension, and is
provided with a plurality of refrigerant passages extended in a
tube longitudinal direction and arranged in parallel in a tube
widthwise direction, wherein both ends of each of said heat
exchanging tubes are communicated with said pair of header tanks so
that said refrigerant passages of each of said heat exchanging
tubes are grouped in the tube widthwise direction in accordance
with each tank portion of said header tanks, to thereby form a
plurality of passes arranged in parallel in the tube widthwise
direction, and wherein refrigerant introduced into a first tank
portion of one of said header tanks is introduced into a first tank
portion of the other of said header tanks via a first pass, then
the refrigerant is introduced into a second tank portion of the
other of said header tanks via said refrigerant turning
communication aperture, and thereafter the refrigerant is
introduced into a second tank portion of said one of said header
tanks via a second pass.
17. The refrigerant system as recited in claim 16, wherein CO.sub.2
is used as the refrigerant.
18. A gas cooler using supercritical refrigerant in which a
plurality of heat exchanging tubes are disposed between a pair of
header tanks and arranged in parallel in a header tank longitudinal
direction, wherein each of said header tanks is provided with one
or more partitioning walls integrally formed in each of said header
tanks and extended in the header tank longitudinal direction,
whereby a plurality of tank portions divided by said one or more
partitioning walls and extended in the header tank longitudinal
direction are formed so as to be arranged in parallel in a header
tank widthwise direction, wherein a refrigerant turning
communication aperture for communicating adjacent tank portions is
formed in a prescribed partitioning wall, wherein each of said heat
exchanging tubes has a flat configuration having a width dimension
larger than a height dimension, and is provided with a plurality of
refrigerant passages extended in a tube longitudinal direction and
arranged in parallel in a tube widthwise direction, wherein both
ends of each of said heat exchanging tubes are communicated with
said pair of header tanks so that said refrigerant passages of each
of said heat exchanging tubes are grouped in the tube widthwise
direction in accordance with each tank portion of said header
tanks, to thereby form a plurality of passes arranged in parallel
in the tube widthwise direction, wherein refrigerant introduced
into a first tank portion of one of said header tanks is introduced
into a first tank portion of the other of said header tanks via a
first pass, then the refrigerant is introduced into a second tank
portion of the other of said header tanks via said refrigerant
turning communication aperture, and thereafter the refrigerant is
introduced into a second tank portion of said one of said header
tanks via a second pass, and wherein the refrigerant passing
through the first and second passes is cooled by exchanging heat
with ambient air.
19. The gas cooler using supercritical refrigerant as recited in
claim 18, wherein CO.sub.2 is used as the refrigerant.
Description
[0001] Priority is claimed to Japanese Patent Application No.
2002-240927 filed on Aug. 21, 2002 and U.S. Provisional Patent
Application No. 60/407,945 filed on Sep. 5, 2002, the disclosure of
which are incorporated by reference in their entireties.
CROSS REFERENCE TO RELATED APPLICATIONS
[0002] This application is an application filed under 35 U.S.C.
.sctn.111(a) claiming the benefit pursuant to 35 U.S.C.
.sctn.119(e)(1) of the filing date of U.S. Provisional Application
No. 60/407,945 filed on Sep. 5, 2002 pursuant to 35 U.S.C.
.sctn.111(b).
TECHNICAL FIELD
[0003] The present invention relates to a heat exchanger, etc. for
use in automobile air-conditioners, household air-conditioners,
electric device coolers and the like having a refrigeration cycle
using CO.sub.2 refrigerant.
BACKGROUND ART
[0004] Since Freon refrigerant used as refrigerant for
air-conditioning apparatuses is an ozone depleting substance and a
greenhouse substance, a refrigeration cycle using a carbon dioxide
(CO.sub.2), which exists in nature, as refrigerant has been drawn
attention as defreonization air-conditioning techniques.
[0005] In a refrigeration cycle using Freon refrigerant, since the
refrigerant becomes a liquid-gas mixed state during the cooling
(heat rejection) process at the high-pressure circuit side in a
condenser, the refrigerant will be maintained at the condensation
temperature in almost the entire region of the condensing passages.
Accordingly, by employing the so-called cross-flow type heat
exchanger in which condensing passages are disposed in a plane
perpendicular to the cooling air introducing direction in a
meandering manner so as to introduce the cooling air of a constant
temperature throughout the entire condensing passages, the
temperature difference between the refrigerant and the cooling air
can be fully secured in the entire condensing passages, resulting
in high heat exchanging efficiency.
[0006] To the contrary, in a refrigeration cycle using CO.sub.2
refrigerant, the CO.sub.2 refrigerant is operated in a
supercritical state in which no phase change occurs during the heat
rejection process at the high pressure circuit side. Therefore, the
refrigerant temperature deteriorates gradually as it goes from the
entrance side of the heat rejection passages toward the exit side
thereof. However, in the aforementioned cross-flow type heat
exchanger, a cooling air of a constant temperature is introduced in
the entire region of the heat rejection passages. Thus, in cases
where this cross-flow type heat exchanger is used as a gas cooler
(heat rejection device) having a refrigeration cycle using CO.sub.2
refrigerant, the temperature difference between the refrigerant and
the cooling air becomes uneven in the heat rejection passages such
that the temperature difference becomes larger at the inlet side of
the heat rejection passages and smaller at the outlet side thereof.
This makes it difficult to obtain high heat exchanging
efficiency.
[0007] To cope with this problem, by employing the so-called
counter flow type heat exchanger in which heat rejection passages
are disposed in a meandering manner so as to extend in a direction
opposite to the cooling air introducing direction so that the
cooling air temperature at the exit side of the heat rejection
passage is lower than that at the inlet side thereof, an enough
temperature difference between the refrigerant and the cooling air
can be secured in the entire heat rejection passages, resulting in
improved heat exchanging efficiency.
[0008] This kind of conventional counter flow type heat exchanger
is disclosed by, for example, Japanese Unexamined Laid-open Utility
Model Publication No. 57-66389 and Japanese Unexamined Laid-open
Patent Publication No. 10-288476.
[0009] In these heat exchangers, a plurality of heat exchanging
tubes are disposed in parallel and arranged in the up and down
direction with both ends thereof connected to a pair of header
tanks disposed along the up and down direction in fluid
communication. The heat exchanging tube has a flat configuration
with a wide width, and is provided with a plurality of refrigerant
passages extending in the longitudinal direction of the tube and
arranged in the widthwise direction (fore and aft direction) of the
tube. On the other hand, in one of the header tanks, a partitioning
plate is provided along the longitudinal direction (in the up and
down direction). Thus, the inside space of the header tank is
divided into a front half space and a rear half space by the
partitioning plate. The rear half space is communicated with the
rear half side of the refrigerant passages of heat exchanging
tubes, while the front half space is communicated with the front
half side of the refrigerant passages of the heat exchanging
tubes.
[0010] Thus, the refrigerant flowed into the rear half space of one
of the header tanks passes through the rear half side of the
refrigerant passages (first pass) of the heat exchanging tubes and
flows into in the other of the header tanks. Then, the refrigerant
passes through the front half side of the refrigerant passages
(second pass) of the heat exchanging tubes to be introduced into
the front half space of the one of header tanks and then flows out.
In this way, the refrigerant passes through the first and second
passes in this order, while the cooling air introduced from the
front side of the heat exchanger passes through the second and
first passes in this order, whereby the refrigerant exchanges heat
with the cooling air.
[0011] In the refrigeration cycle using CO.sub.2 refrigerant,
however, the refrigerant working pressure at the high pressure
circuit side becomes higher as much as about 10 times as compared
with a refrigeration cycle using Freon refrigerant. Therefore, in
the aforementioned conventional heat exchanger with a partitioning
plate in the header tank, the mounting strength and the positioning
accuracy of the partitioning plate become inadequate, causing
insufficient pressure resistance, which deteriorates the
air-tightness at the joint portions of the partitioning plate.
Especially, in a quasi counter flow type heat exchanger in which a
plurality of refrigerant passages provided in a flat heat
exchanging tube are grouped into a plurality of passes, it becomes
difficult to fully secure the air-tightness at the joint portions
of the partitioning plate and the heat exchanging tube end
portions. This may cause an introduction of the refrigerant into
the adjacent passages, which deteriorates heat exchange
performance.
[0012] It is an object of the present invention to solve the
problems of the aforementioned conventional techniques and provide
a heat exchanger capable of obtaining sufficient pressure
resistance, preventing refrigerant leakage and improving heat
exchange performance. It is another object of the present invention
to provide a tube connecting structure of a heat exchanger header
tank and a refrigeration system.
DISCLOSURE OF INVENTION
[0013] According to the first aspect of the present invention, a
heat exchanger, comprises:
[0014] a pair of header tanks; and
[0015] a plurality of heat exchanging tubes disposed between the
pair of header tanks and arranged in parallel in a header tank
longitudinal direction,
[0016] wherein each of the header tanks is provided with one or
more partitioning walls integrally formed in each of the header
tanks and extended in the header tank longitudinal direction,
whereby a plurality of tank portions divided by the one or more
partitioning walls and extended in the header tank longitudinal
direction are formed and arranged in parallel in a header tank
widthwise direction, wherein a refrigerant turning communication
aperture for communicating adjacent tank portions is formed in a
prescribed partitioning wall,
[0017] wherein each of the heat exchanging tubes has a flat
configuration having a width dimension larger than a height
dimension, and is provided with a plurality of refrigerant passages
extended in a tube longitudinal direction and arranged in parallel
in a tube widthwise direction,
[0018] wherein both ends of each of the heat exchanging tubes are
communicated with the pair of header tanks so that the refrigerant
passages of each of the heat exchanging tubes are grouped in the
tube widthwise direction in accordance with each tank portion of
the header tanks, to thereby form a plurality of passes arranged in
parallel in the tube widthwise direction, and
[0019] wherein refrigerant introduced into a first tank portion of
one of the header tanks is introduced into a first tank portion of
the other of the header tanks via a first pass, then the
refrigerant is introduced into a second tank portion of the other
of the header tanks via the refrigerant turning communication
aperture, and thereafter the refrigerant is introduced into a
second tank portion of the one of the header tanks via a second
pass.
[0020] In the heat exchanger according to the first aspect of the
present invention, since the heat exchanger has the co-called
counter flow type refrigerant circuit in which refrigerant passes
in a meandering manner against the introducing direction of cooling
air, an appropriate temperature difference between the refrigerant
and the cooling air such as CO.sub.2 can be secured through all of
the passes, causing efficient heat exchanging, which results in
excellent heat exchanging performance.
[0021] Furthermore, since the partitioning wall is integrally
formed in the header tank, enough air-tightness especially at the
partitioning wall portion can be secured, resulting in enough
durability. Furthermore, refrigerant mixture due to leaking can be
prevented assuredly, which further improved heat exchanging
performance.
[0022] In the first aspect of the present invention, it is
preferable that each of the header tanks is an integrally formed
article formed by extrusion processing or drawing processing, or
that the heat exchanging tube is an integrally formed article
formed by extrusion processing or drawing processing.
[0023] In these cases, the pressure resistance can be further
improved and the manufacturing efficiency can be improved by
employing extrusion processing or drawing processing which are
suitable for mass production.
[0024] Furthermore, in the first aspect of the present invention,
it is preferable that a plurality of tube insertion apertures
communicating with the tank portions are provided at an inner side
surface of each of the header tanks at certain intervals in the
header tank longitudinal direction, and that refrigerant passages
at end portions of the heat exchanging tubes are communicated with
corresponding tube insertion apertures.
[0025] In this case, the end portions of the heat exchanging tubes
can be brazed to the header tanks in a stable manner, which can
further improve the pressure resistance while preventing poor
joining at the joined portions assuredly.
[0026] Furthermore, in the first aspect of the present invention,
it is preferable that end portions of each of the heat exchanging
tubes are provided with one or more cutout portions corresponding
to the one or more partitioning walls and that the end portions of
each of the heat exchanging tubes are inserted into the tube
insertion apertures with the one or more partitioning walls fitted
in the one or more cutout portions.
[0027] In this case, since the cutout portions of the tube end
portion is engaged with the partitioning wall, the positioning of
the tube end portion in the insertion direction and in a direction
perpendicular to the insertion direction can be performed
correctly. Thus, the tube insertion can be performed easily.
Furthermore, enough joining area of the tube to the header tank can
be secured, enabling a stable joining status, which can prevent
poor joining more assuredly and further improve the pressure
resistance.
[0028] Furthermore, in the first aspect of the present invention,
it is more preferable that one or more regions of each of the heat
exchanging tubes corresponding to the one or more cutout portions
are formed to be one or more non-passage areas in which no
refrigerant passage exists and that regions of each of the heat
exchanging tubes not corresponding to the one or more cutout
portions are formed to be passage areas in which the refrigerant
passages exist.
[0029] In this case, it is possible to effectively prevent such a
problem that cutout portions are formed in passages of the heat
exchanger.
[0030] Furthermore, in the first aspect of the present invention,
it is more preferable that the refrigerant turning communication
aperture formed in the partitioning wall of the other of the header
tanks is configured by a cut aperture formed in an inside surface
of the other of the header tanks.
[0031] In this case, the refrigerant turning communication aperture
can be assuredly formed by such a simple operation that cutting is
performed to the inside surface side of the header tank, which in
turn can further improve the productive efficiency of the heat
exchanger itself.
[0032] Furthermore, in the first aspect of the present invention,
it is more preferable that each of the header tanks is provided
with a joining plate joined to an inner side surface thereof,
wherein a plurality of tube insertion apertures are provided in the
joining plate at certain intervals in a joining plate longitudinal
direction, and that end portions of each of the heat exchanging
tubes are inserted into corresponding tube insertion apertures to
be communicated with the header tanks.
[0033] Furthermore, in the first aspect of the present invention,
in cases where the refrigerant turning communication aperture is
configured by a cut aperture formed in an inside surface of the
header tank, the aperture can be formed by simply performing
cutting to the inside surface of the header tank.
[0034] In this case, the rigidity of the tank itself can be
improved, which further improves the durability of the entire heat
exchanger. Furthermore, the sealing processing of the refrigerant
turning communication aperture formed in the inside surface of the
header tank can be performed easily and assuredly, which in turn
can further improve the productive efficiency of the heat exchanger
itself.
[0035] Furthermore, as explained above, since the first aspect of
the present invention specifies the so-called counter flow type
heat exchanger which is excellent in pressure resistance, the heat
exchanger according to the first aspect of the present invention
can be preferably used as a heat exchanger using CO.sub.2.
[0036] That is, in the first aspect of the present invention, it is
preferable that CO.sub.2 is used as the refrigerant.
[0037] The aforementioned preferable structures can be employed as
preferable structures of the below mentioned second to sixth
aspects of the present invention.
[0038] The second aspect of the present invention specifies an
embodiment of a manufacturing process for manufacturing the
aforementioned heat exchanger according to the first aspect of the
present invention.
[0039] According to the method for manufacturing a heat exchanger
of the second aspect of the present invention, the method
comprises:
[0040] preparing a pair of header tanks, wherein each of the header
tanks is provided with one or more partitioning walls integrally
formed in each of the header tanks and extended in a header tank
longitudinal direction, whereby a plurality of tank portions
divided by the one or more partitioning walls and extended in the
header tank longitudinal direction are formed so as to be arranged
in parallel in a header tank widthwise direction, wherein a
refrigerant turning communication aperture for communicating
adjacent tank portions is formed in predetermined partitioning
walls;
[0041] preparing a plurality of heat exchanging tubes, wherein each
of the heat exchanging tubes has a flat configuration having a
width dimension larger than a height dimension, and is provided
with a plurality of refrigerant passages extended in a tube
longitudinal direction and arranged in parallel in a tube widthwise
direction; and
[0042] forming a plurality of passes arranged in parallel in the
tube widthwise direction by communicating both ends of each of the
heat exchanging tubes with the pair of header tanks so that the
refrigerant passages of each heat exchanging tubes are grouped into
the plurality of passes in the tube widthwise direction in
accordance with each of the tank portions of the header tank,
[0043] whereby refrigerant introduced into a first tank portion of
one of the header tanks is introduced into a first tank portion of
the other of the header tanks via a first pass, then the
refrigerant is introduced into a second tank portion of the other
of the header tanks via the refrigerant turning communication
aperture, and thereafter the refrigerant is introduced into a
second tank portion of the one of the header tanks via a second
pass.
[0044] In the second aspect of the present invention, since the
second aspect of the present invention specifies an embodiment of a
manufacturing process for manufacturing the aforementioned heat
exchanger according to the first aspect of the present invention, a
heat exchanger having the same effects as mentioned above can be
manufactured.
[0045] In the second aspect of the present invention, it is
preferable that at least one of the header tanks is provided, at
its inner surface side, with a plurality of tube insertion
apertures for communicating end portions of the heat exchanging
tubes and the refrigerant turning communication aperture, and that
the tube insertion apertures and the refrigerant turning
communication aperture are formed simultaneously by cutting
processing.
[0046] In this case, the number of processing operations can be
reduced, resulting in further improved product efficiency.
[0047] The third aspect of the present invention specifies a heat
exchanger which can be preferably used as a heat exchanger using
CO.sub.2 refrigerant among heat exchangers according to the first
aspect of the present invention.
[0048] According to the third aspect of the present invention, a
heat exchanger, comprises:
[0049] a pair of header tanks; and
[0050] a plurality of heat exchanging tubes disposed between the
pair of header tanks and arranged in a header tank longitudinal
direction,
[0051] wherein each of the header tanks is provided with three
partitioning walls integrally formed in each of header tanks and
extended in the header tank longitudinal direction, whereby a first
tank portion to a fourth tank portion divided by the partitioning
walls and extended in the header tank longitudinal direction are
formed so as to be arranged in parallel in a header tank widthwise
direction, wherein a refrigerant turning communication aperture for
communicating adjacent tank portions is formed in a partitioning
wall partitioning the second tank portion and the third tank
portion of the one of the header tanks, a partitioning wall
partitioning the first tank portion and the second tank portion of
the other of the header tanks and a partitioning wall partitioning
the third tank portion and the fourth tank portion of the other of
the header tanks,
[0052] wherein each of the heat exchanging tubes has a flat
configuration having a width dimension larger than a height
dimension, and is provided with a plurality of refrigerant passages
extended in a tube longitudinal direction and arranged in parallel
in a tube widthwise direction,
[0053] wherein both ends of each of the heat exchanging tubes are
communicated with the pair of header tanks so that the refrigerant
passages of each of the heat exchanging tubes are grouped in the
tube widthwise direction in accordance with each tank portion of
the header tanks, to thereby form a first to fourth passes arranged
in parallel in the tube widthwise direction, and
[0054] wherein refrigerant introduced into the first tank portion
of one of the header tanks passes through the first to fourth
passes in turn and then introduced into the fourth tank portion of
the one of the header tanks.
[0055] Since the third aspect of the present invention specifies a
heat exchanger which can be preferably used as a heat exchanger
using CO.sub.2 refrigerant among heat exchangers according to the
first aspect of the present invention, the aforementioned effects
can be obtained.
[0056] The fourth aspect of the present invention specifies a tube
connecting structure for a header tank of a heat exchanger which is
a principal portion of the heat exchanger according to the first
aspect of the present invention.
[0057] According to the fourth aspect of the present invention, a
tube connecting structure for a header tank of a heat exchanger
comprising a pair of header tanks and a plurality of heat
exchanging tubes disposed between the pair of header tanks and
arranged in a header tank longitudinal direction,
[0058] wherein each of the header tanks is provided with one or
more partitioning walls integrally formed in each of header tanks
and extended in the header tank longitudinal direction, whereby a
plurality of tank portions divided by the partitioning walls and
extended in the header tank longitudinal direction are formed so as
to be arranged in parallel in a header tank widthwise
direction,
[0059] wherein tube insertion apertures communicating with the tank
portions are formed in one side surface of each of the header
tanks, wherein each of the heat exchanging tubes has a flat
configuration having a width dimension larger than a height
dimension, and is provided with a plurality of refrigerant passages
extending in a tube longitudinal direction and arranged in parallel
in a tube widthwise direction,
[0060] wherein both ends of each of the heat exchanging tubes are
communicated with the pair of header tanks so that the refrigerant
passages of each of the heat exchanging tubes are grouped in the
tube widthwise direction in accordance with each tank portion of
the header tanks, to thereby form a plurality of passes arranged in
parallel in the tube widthwise direction, and
[0061] wherein refrigerant passes through each of the grouped
refrigerant passages independently.
[0062] In the fourth aspect of the present invention, since the
fourth aspect of the present invention specifies a tube connecting
structure for a header tank of a heat exchanger which is a
principal portion of the heat exchanger according to the first
aspect of the present invention, the aforementioned effects can be
obtained.
[0063] In the fourth aspect of the present invention, in the same
manner as in the first aspect of the present invention, it is
preferable that end portions of the heat exchanging tubes are
provided with one or more cutout portions corresponding to the one
or more partitioning walls, and the end portions of the heat
exchanging tubes are inserted into the tube insertion apertures
with the one or more partitioning walls fitted in the one or more
cutout portions, or that one or more regions of each of the heat
exchanging tubes corresponding to the one or more cutout portions
are formed to be one or more non-passage areas in which no
refrigerant passage exists, and wherein regions of each of the heat
exchanging tubes not corresponding to the one or more cutout
portions are formed to be passage areas in which the refrigerant
passages exist.
[0064] The fifth aspect of the present invention specifies a
refrigerant system using the heat exchanger according to the first
aspect of the present invention.
[0065] According to the fifth aspect of the preset invention, a
refrigerant system having a refrigeration cycle in which
refrigerant compressed by a compressor is cooled by a gas cooler,
decompressed by a decompressor, then heated while passing through a
cooling device and then returned to the compressor,
[0066] wherein the gas cooler is configured by a heat exchanger
comprising a pair of header tanks and a plurality of heat
exchanging tubes disposed between the pair of header tanks and
arranged in a header tank longitudinal direction,
[0067] wherein each of the header tanks is provided with one or
more partitioning walls integrally formed in each of the header
tanks and extended in the header tank longitudinal direction,
whereby a plurality of tank portions divided by the one or more
partitioning walls and extended in the header tank longitudinal
direction are formed so as to be arranged in parallel in a header
tank widthwise direction, wherein a refrigerant turning
communication aperture for communicating adjacent tank portions is
formed in a prescribed partitioning wall,
[0068] wherein each of the heat exchanging tubes has a flat
configuration having a width dimension larger than a height
dimension, and is provided with a plurality of refrigerant passages
extended in a tube longitudinal direction and arranged in parallel
in a tube widthwise direction,
[0069] wherein both ends of each of the heat exchanging tubes are
communicated with the pair of header tanks so that the refrigerant
passages of each of the heat exchanging tubes are grouped in the
tube widthwise direction in accordance with each tank portion of
the header tanks, to thereby form a plurality of passes arranged in
parallel in the tube widthwise direction, and
[0070] wherein refrigerant introduced into a first tank portion of
one of the header tanks is introduced into a first tank portion of
the other of the header tanks via a first pass, then the
refrigerant is introduced into a second tank portion of the other
of the header tanks via the refrigerant turning communication
aperture, and thereafter the refrigerant is introduced into a
second tank portion of the one of the header tanks via a second
pass.
[0071] Since the fifth aspect of the present invention specifies a
refrigerant system using the heat exchanger according to the first
aspect of the present invention, the similar effects as mentioned
above can be obtained.
[0072] The fifth aspect of the present invention can be preferably
employed as a refrigerant system using CO.sub.2 refrigerant.
[0073] In the fifth aspect of the present invention, it is
preferable that CO.sub.2 is used as refrigerant.
[0074] The sixth aspect of the present invention specifies a gas
cooler using supercritical refrigerant in which the heat exchanger
according to the first aspect of the present invention is
utilized.
[0075] According to the sixth aspect of the present invention, a
gas cooler using supercritical refrigerant in which a plurality of
heat exchanging tubes are disposed between a pair of header tanks
and arranged in parallel in a header tank longitudinal
direction,
[0076] wherein each of the header tanks is provided with one or
more partitioning walls integrally formed in each of the header
tanks and extended in the header tank longitudinal direction,
whereby a plurality of tank portions divided by the one or more
partitioning walls and extended in the header tank longitudinal
direction are formed so as to be arranged in parallel in a header
tank widthwise direction, wherein a refrigerant turning
communication aperture for communicating adjacent tank portions is
formed in a prescribed partitioning wall,
[0077] wherein each of the heat exchanging tubes has a flat
configuration having a width dimension larger than a height
dimension, and is provided with a plurality of refrigerant passages
extended in a tube longitudinal direction and arranged in parallel
in a tube widthwise direction,
[0078] wherein both ends of each of the heat exchanging tubes are
communicated with the pair of header tanks so that the refrigerant
passages of each of the heat exchanging tubes are grouped in the
tube widthwise direction in accordance with each tank portion of
the header tanks, to thereby form a plurality of passes arranged in
parallel in the tube widthwise direction,
[0079] wherein refrigerant introduced into a first tank portion of
one of the header tanks is introduced into a first tank portion of
the other of the header tanks via a first pass, then the
refrigerant is introduced into a second tank portion of the other
of the header tanks via the refrigerant turning communication
aperture, and thereafter the refrigerant is introduced into a
second tank portion of the one of the header tanks via a second
pass, and
[0080] wherein the refrigerant passing through the first and second
passes is cooled by exchanging heat with ambient air.
[0081] In the sixth aspect of the present invention, since the
sixth aspect of the present invention specifies a gas cooler using
supercritical refrigerant in which the heat exchanger according to
the first aspect of the present invention is utilized, the similar
effects as mentioned above can be employed.
[0082] The sixth aspect of the present invention can be preferably
used as a gas cooler using CO.sub.2.
[0083] In the sixth aspect of the present invention, it is
preferable that CO.sub.2 is used as the refrigerant.
[0084] In the present invention, "up and down direction" or "fore
and aft direction" are not defied based on gravity direction. For
the explanatory purposes, the air introducing direction is defined
as "fore and aft direction." In other words, the heat exchanger or
the like according to the present invention is not limited in
installation direction. For example, in the heat exchanger or the
like according to the present invention, the longitudinal direction
of the header tank can be disposed along any direction including
horizontal direction, slant direction as well as vertical direction
relative to the gravity direction.
BRIEF DESCRIPTION OF DRAWINGS
[0085] FIG. 1 is a perspective view showing a gas cooler using
CO.sub.2 refrigerant employed as a heat exchanger according to an
embodiment of the present invention.
[0086] FIG. 2 is an exploded perspective view showing one of the
header tanks and its vicinity of the gas cooler of the
embodiment.
[0087] FIG. 3 is an exploded horizontal cross-sectional view
showing the gas cooler of the embodiment.
[0088] FIG. 4 is an assembled horizontal cross-sectional view
showing the gas cooler of the embodiment.
[0089] FIG. 5 shows an end portion of the heat exchanging tube
employed in the gas cooler according to the present invention,
wherein FIG. 5A is the plan view thereof and FIG. 5B is the end
view thereof.
[0090] FIG. 6 is an exploded horizontal cross-sectional view
showing the header tank and its vicinity of a gas cooler which is a
modified embodiment of the present invention.
[0091] FIG. 7 is an assembled horizontal cross-sectional view
showing the header tank and its vicinity of a gas cooler which is
the modified embodiment of the present invention.
[0092] FIG. 8 shows an end portion of the heat exchanging tube
employed in the gas cooler according to the modified embodiment,
wherein FIG. 5A is the plan view thereof and FIG. 5B is the end
view thereof.
[0093] FIG. 9 is a schematic refrigerant circuit diagram showing
the refrigerant flow of the gas cooler according to Example 1
relevant to the present invention.
[0094] FIG. 10 is a schematic refrigerant circuit diagram showing
the refrigerant flow of the gas cooler according to Example 2
relevant to the present invention.
[0095] FIG. 11 is a schematic refrigerant circuit diagram showing
the refrigerant flow of the gas cooler according to Comparative
Example which is out of the scope of the present invention.
[0096] FIG. 12 is a graph showing the relationship between the
refrigerant flow direction and the refrigerant temperature/cooling
air temperature in the gas cooler according to the Examples.
BEST MODE FOR CARRYING OUT THE INVENTION
[0097] FIG. 1 is a perspective view showing a gas cooler applied to
a heat exchanger according to an embodiment of the present
invention, and FIG. 2 is an exploded perspective view showing one
of the header tanks and its vicinity of the gas cooler. This heat
exchanger is employed in a refrigeration cycle using CO.sub.2
refrigerant. As shown in FIGS. 1 and 2, this heat exchanger is
provided with a pair of right and left flat header tanks 10a and
10b disposed along an up and down direction, a plurality of flat
heat exchanging tubes 30 disposed between the header tanks 10a and
10b and arranged in parallel in the header tank longitudinal
direction (up and down direction) with the opposite ends thereof
connected to the header tanks 10a and 10b in fluid communication,
and corrugated fins each disposed between the adjacent upper and
lower heat exchanging tubes 30, as fundamental structural
elements.
[0098] As shown in FIGS. 1 to 4, each of the header tanks 10a and
10b is an integrally formed metal article made of, for example,
aluminum (including its alloy), and is provided with four tank
portions, i.e., the first tank portion 11 to the fourth tank
portion 14, extending in the header tank longitudinal direction.
Between the adjacent tank portions 11 to 14, a partitioning wall 15
is formed, respectively, to thereby air-tightly partition the
adjacent tank portions.
[0099] In the inner surface side of each of the header tanks 10a
and 10b, corresponding to each of the tank portions 11 to 14, a
plurality of tube insertion apertures 16 arranged at certain
intervals in the longitudinal direction (in the up and down
direction) are formed. Each tube insertion aperture 16 is formed
into an elongated configuration extending in the header tank
widthwise direction and communicated with the corresponding tank
portion 11 to 14.
[0100] Between the adjacent upper and lower tube insertion
apertures 16 at the inner surface side of one of the header tanks
10a, refrigerant turning communication apertures 17 are formed by
cutting out the partitioning wall 15 partitioning the second and
third tank portions 12 and 13. With these refrigerant turning
communication apertures 17, the second and third tank portions 12
and 13 are in fluid communication with each other, so that
refrigerant can flow from the second tank portion 12 to the third
tank portion 13.
[0101] Furthermore, at the longitudinal middle portion of the rear
side of one of the header tanks 10a, a refrigerant inlet 1
communicating with the first tank portion 11 is formed, while at
the longitudinal middle portion of the front side thereof, a
refrigerant outlet 2 communicating with the fourth tank portion 14
is formed.
[0102] Between the adjacent upper and lower tube insertion
apertures 16 at the inner surface side of the other of the header
tanks 10b, refrigerant turning communication apertures 17 are
formed by cutting out the partitioning wall 15 partitioning the
first and second tank portions 11 and 12 and the partitioning wall
15 partitioning the third and fourth tank portions 13 and 14. With
these refrigerant turning communication apertures 17, the first and
second tank portions 11 and 12 and the third and fourth tank
portions 13 and 14 are in fluid communication with each other,
respectively, so that refrigerant can flow from the first tank
portion 11 to the second tank portion 12 and the third tank portion
13 to the fourth tank portion 14, respectively.
[0103] As shown in FIGS. 1 and 2, at the upper and lower end
portions of the inner surface side of each of the header tanks 10a
and 10b, a closing slit 18 is formed by cutting in the tank
widthwise direction (in the fore and aft direction) so as to cross
all of the tank portions 11 to 14 in the widthwise direction
thereof, respectively. In each closing slit 18, a closing plate 19
is fitted in and brazed thereto. Thus, the upper and lower end
portions of each tank portion 11 to 14 of each of the header tank
portions 10a and 10b are air-tightly sealed by the closing plate
19, respectively.
[0104] As shown in FIGS. 1 to 4, a joining plate 20 is brazed to
the inner surface of each of the header tanks 10a and 10b so as to
close the refrigerant turning communication apertures 17. This
joining plate 20 is provided with a plurality of tube insertion
apertures 21 corresponding to the tube insertion apertures 16 of
the header tank 10a and 10b arranged at certain intervals in the
longitudinal direction (i.e., in the up and down direction).
[0105] In this embodiment, the header tanks 10a and 10b can be
formed by extrusion processing or drawing processing.
[0106] In detail, after forming a tank intermediate having tank
portions 11 to 14 by extrusion processing or drawing processing,
the tube insertion apertures 16, the refrigerant turning
communication apertures 17 and the closing slits 18 are formed by
subjecting the tank intermediate to cutting processing, to thereby
obtain the header tanks 10a and 10b. By integrally forming the
partitioning walls 15 in each of the header tanks 10a and 10b by
extrusion processing, the air-tightness of the partitioning walls
15 can be improved, resulting in sufficient pressure
resistance.
[0107] In this embodiment, cutting processing executed to each of
the header tanks 10a and 10b, i.e., cutting processing to form the
tube insertion apertures 16, cutting processing to form the
refrigerant turning communication apertures 17 and cutting
processing to form the closing slits 18, are simultaneously
performed to decrease the number of processing steps and improve
the manufacturing efficiency.
[0108] Furthermore, in this embodiment, after the aforementioned
cutting processing, it is preferable that the inner surface of each
of the header tanks 10a and 10b, i.e., the joining surface to which
the joining plate 20 is joined, is subjected to milling processing
to obtain a flat and smooth surface. By forming the inner surface
of each of the header tanks into such a flat and smooth surface,
the joining area of the joining plate 20 to be integrally joined to
the inner surface can be kept larger, causing improved joining
degree (adherence degree) and increased strength, which in turn can
further improve the pressure resistance.
[0109] The aforementioned joining plate 20 can be formed by, for
example, calendaring processing, extruding processing or drawing
processing. In detail, the joining plate 20 can be formed by
subjecting the plate-shaped intermediate to cutting or drilling
processing to form the tube insertion apertures 21 after forming a
plate-shaped intermediate made of metal such as aluminum (including
its alloy).
[0110] Needless to say, in the present invention, the processing
methods of the header tanks 10a and 10b and the joining plates 20
are not limited to the above.
[0111] As shown in FIGS. 2 to 5, each of the heat exchanging tubes
30 is constituted by an extruded article or a drawn article made of
metal such as aluminum (including its alloy), and has a flat
cross-sectional configuration. In the heat exchanging tube 30, a
plurality of refrigerant passage 35 each extending in the
longitudinal direction and having a rectangular cross-section are
arranged in parallel in the tube widthwise direction.
[0112] The refrigerant passages 35 are grouped into a total of four
passage groups in the tube widthwise direction corresponding to the
first to fourth tank portions 11 to 14 of the header tanks 10a to
10b. The refrigerant passages 35 of each of the four passage groups
constitute the first pass P1 to the fourth pass P4 in this order
from the rear side.
[0113] Furthermore, in the non-refrigerant-passage-forming regions
of the end portions of each heat exchanging tube 30 in which no
refrigerant passage is formed, in other words, in the regions of
the end portions between adjacent passes P1 to P4, a cutout portion
36 is formed, respectively. Fitted to the cutout portions 36 are
the corresponding regions of the joining plate 20 located between
the adjacent tube insertion apertures 21 arranged in the fore and
aft direction (in the widthwise direction) and the corresponding
partitioning walls 15 of the header tank 10a and 10b. Thus, the
refrigerant-passage-forming regions of each end portion of the heat
exchanging tube 30, i.e., the regions in which the passes P1 to P4
are formed, are inserted into the tube insertion apertures 21 of
the joining plate 20 and the tube insertion apertures 16 of each of
the header tanks 10a and 10b.
[0114] Thus, a plurality of heat exchanging tubes 30 are disposed
between the pair of header tanks 10a and 10b and arranged in
parallel at certain intervals in the up and down direction with the
opposite ends thereof connected to the pair of header tanks 10a and
10b disposed along the up and down direction via the joining plate
20. In this state, the required portions thereof are integrally
brazed.
[0115] Thus, the first to fourth passes P1 to P4 of each heat
exchanging tube 30 are arranged in parallel within a plan in this
order from the rear side.
[0116] Between the adjacent heat exchanging tubes 30, a corrugated
fin 40 made of metal such as aluminum (including its alloy) is
disposed. In this state, the required portions are integrally
brazed.
[0117] A refrigerant inlet pipe 51 is connected to the refrigerant
inlet 1 of one of the header tanks 10a in fluid communication and
integrally brazed thereto, while a refrigerant outlet pipe 52 is
connected to the refrigerant outlet 2 of the other of the header
tanks 10a in fluid communication and integrally brazed thereto.
[0118] In the aforementioned gas cooler according to this
embodiment, although components are made of aluminum or its alloy
as mentioned above, they can be made of aluminum brazing sheets
with brazing materials laminated on at least one surface. These
components are provisionally assembled into a prescribed gas cooler
configuration via brazing materials. Then, this entire provisional
product is brazed in a furnace to thereby obtain an integrally
joined product.
[0119] In the present invention, in assembling the heat exchanger,
partial brazing can be employed or a combination of partial brazing
and entire brazing can be employed. Any assembling method can be
employed.
[0120] The gas cooler configured as mentioned above constitutes a
refrigeration cycle using CO.sub.2 together with a compressor, a
decompression expanding device and a cooler, and forms a
refrigerant system for use in car air-conditioners. In this
refrigerant system, an outlet side of the compressor is connected
to the refrigerant inlet pipe 51 of the gas cooler, while the
refrigerant outlet pipe 52 is connected to an inlet side of the
decompression expanding device.
[0121] In this refrigeration system, CO.sub.2 refrigerant
compressed by a compressor is introduced into the first tank
portion 11 of one of the header tanks 10a of the gas cooler via the
refrigerant inlet pope 51.
[0122] The refrigerant introduced into the first tank portion 11 of
one of the header tanks 10a passes through the first pass P1 and
then introduced into the first tank portion 11 of the other of the
header tanks 10b. Then, the refrigerant is introduced into the
second tank portion 12 in the header tank 10b via the refrigerant
turning communication apertures 17.
[0123] The refrigerant introduced into the second tank portion 12
of the other of the header tanks 10b passes through the second pass
P2 and then introduced into the second tank portion 12 in the one
of the header tanks 10a. Thereafter, the refrigerant is introduced
into the third tank portion 13 of the header tank 10a via the
refrigerant turning communication apertures 17.
[0124] The refrigerant introduced into the third tank portion 13 of
the one of the header tanks 10a passes through the third pass P3,
then introduced into the third tank portion 13. Thereafter, the
refrigerant is introduced into the fourth tank portion 14 of the
header tank 10b via the refrigerant turning communication apertures
17.
[0125] The refrigerant introduced into the fourth tank portion 14
of the other of the header tanks 10b passes through the fourth pass
P4, and then introduced into the fourth tank portion 14 of the one
of the header tanks 10a. Thereafter, the refrigerant flows out via
the refrigerant outlet pipe 52.
[0126] As mentioned above, the refrigerant exchanges heat with the
cooling air A introduced from the front side of the gas cooler
while passing through the first to fourth passes P1 to P4 in this
order, to be gradually cooled.
[0127] The cooling air A is introduced from the front side of the
gas cooler and passes from the fourth pass P4 toward the first pass
P1 in this order to cool the refrigerant in each pass. The cooling
air is gradually increased in temperature, and then discharged from
the rear side of the gas cooler. On the other hand, the refrigerant
passes the first pass P1 to the fourth pass P4 from the rear side
in this order, and is gradually decreased in temperature. That is,
the refrigerant of high temperature immediately after being
introduced into the gas cooler exchanges heat with the air A of
relatively high temperature immediately before being discharged,
while the refrigerant of low temperature immediately before being
discharged exchanges heat with the air A of low temperature
immediately after being introduced into the gas cooler. Therefore,
the refrigerant can keep an appropriate temperature difference
relative to the air A in all of the passes P1 to P4, causing
efficient heat exchanging, which enables excellent heat exchanging
performance.
[0128] The cooled refrigerant is decompressed and expanded by a
decompression expanding device to be cooled. Thereafter, the
refrigerant cools the air in an automobile via a cooling device
while being heated, and then returns to a compressor.
[0129] As mentioned above, the gas cooler of this embodiment has a
counter flow type refrigerant circuit in which refrigerant is
forced to flow against the introducing direction of the cooling air
A. Therefore, an appropriate temperature difference between the
refrigerant and the cooling air A can be kept through the entire
circuit from the starting of cooling the refrigerant to the ending
of cooling the refrigerant, causing efficient heat exchanging,
which enables excellent heat exchanging performance.
[0130] Furthermore, in the gas cooler according to this embodiment,
each of the header tanks 10a and 10b is constituted by an
integrally formed article formed by extrusion processing and the
partitioning walls 15 are integrally formed thereto. Therefore, the
air-tightness of the partitioning walls 15 can be assuredly secured
while obtaining enough pressure resistance. Furthermore, a mixture
of refrigerant due to leakage at the partitioning walls 15 can be
prevented, resulting in excellent heat exchanging performance.
[0131] Furthermore, since the heat exchanging tube 30 is
constituted by an integrally formed article formed by extrusion
processing, enough pressure resistance of the heat exchanging tube
can be obtained.
[0132] Furthermore, since the header tanks 10a and 10b and the heat
exchanging tubes 30 are formed by extrusion processing which is
excellent in mass production, the manufacturing efficiency can be
improved.
[0133] In this embodiment, since the end portions of each heat
exchanging tube 30 are inserted into the header tanks 10a and 10b
and then secured thereto, the stable brazing can be attained. This
enables to improve the pressure resistance while preventing
generation of joining defects.
[0134] Furthermore, in this embodiment, cutout portions 36 are
formed in the end portions of the heat exchanging tube 30, and the
heat exchanging tube 30 is secured to the header tanks 10a and 10b
with the partitioning walls 15 engaged with the cutout portions 36.
Therefore, this engaging enables accurate positioning of the tube
end portions in the insertion direction and in a direction
perpendicular to the insertion direction and easy insertion
operation of the tube 30. Furthermore, an enough joining area of
the tube 30 relative to the header tank 10a and 10b can be secured,
enabling an stably secured state, which in turn further improves
the pressure resistance while assuredly preventing generation of
joining defects.
[0135] Furthermore, in this embodiment, since the cutout portions
36 are formed in the non-passage-forming regions of the end
portions of the heat exchanging tube 30 in which no refrigerant
passage is formed, it is assuredly prevented that the cutout
portions 36 are formed in the regions in which refrigerant passages
35 are formed.
[0136] Furthermore, in this embodiment, since the inner surface
side of the header tank 10a and 10b is subjected to cutting
processing to thereby form the refrigerant turning communication
apertures 17 communicating with adjacent tank portions, the forming
of the apertures 17 can easily be performed.
[0137] Furthermore, in this embodiment, since the forming of the
communication apertures 17 are performed simultaneously with the
forming of the tube insertion apertures 16 and/or the forming of
the closing splits 18, the number of processing steps can be
decreased, enabling efficient boring processing, which in turn can
further improve the manufacturing efficiency.
[0138] Furthermore, in this embodiment, since the header tank 10a
and 10b is reinforced by securing a joining plate 20 to the inner
surface side of the header tank, the pressure resistance can be
further improved.
[0139] Furthermore, since the communication apertures 17 of the
header tank 10a are closed in a sealed manner by securing the
joining plate 20, the sealing operation of the communication
apertures can be eliminated, resulting in further improved
manufacturing efficiency.
[0140] In this embodiment, although the cutout portions 36 are
formed at the end portions of each heat exchanging tube 30 and
engaged with the portions between the tube insertion apertures of
the joining plate 20 and the partitioning walls 15 of the header
tanks 10a and 10b, the present invention is not limited to it.
[0141] For example, the structure as shown in FIGS. 6 to 8 can be
employed. In this structure, protrusions 36 are formed at the
non-passage-forming portions of the end portions of the heat
exchanging tube 30, while a tube insertion aperture 21 continuously
extending in the widthwise direction is formed in the joining plate
20. Further, a tube insertion aperture 16 communicating with the
four tank portions 11 to 14 is formed at the inner surface side of
the header tank 10a and 10b. Corresponding to the tube insertion
aperture 16, penetrated apertures 16a are formed by cutting the
partitioning walls 15 of the header tank 10a and 10b. The end
portion 36 of the heat exchanging tube 30 is inserted into the tube
insertion aperture 21 of the joining plate 20 and the tube
insertion aperture 16 of the header tank 10a and 10b, while the
protruded end portions 36 of the tube are fitted in the penetrated
apertures 16a. In this state, these members are integrally secured
by brazing the necessary portions.
[0142] In this heat exchanger (gas cooler), as mentioned above, the
heat exchanging tubes 30 and the header tanks 10a and 10b can be
secured in a stable manner, resulting in sufficient pressure
resistance.
[0143] In the aforementioned embodiment, a four-pass type gas
cooler having four passes P1 to P4 is exemplified. However, the
present invention is not limited to this, and can be applied to a
heat exchanger having two or more passes.
EXAMPLE 1
[0144] As shown in FIG. 9, in the same manner as in the
aforementioned embodiment, a four-pass counter flow type gas cooler
using CO.sub.2 refrigerant (see FIG. 1) in which the first pass P1
to the fourth pass P4 are formed within a plane parallel to the
introducing direction of air A in a meandering manner in this order
against the introducing direction of the air A from the downstream
side of the air toward the upstream side thereof was prepared.
EXAMPLE 2
[0145] As shown in FIG. 10, a two-pass counter flow type gas cooler
using CO.sub.2 refrigerant in which the first pass P1 and the
second pass P2 are formed within a plane parallel to the
introducing direction of air A in a meandering manner in this order
against the introducing direction of the air A from the downstream
side of the air toward the upstream side thereof was prepared.
COMPARATIVE EXAMPLE
[0146] As shown in FIG. 11, a four-pass cross flow (multi-flow)
type gas cooler using CO.sub.2 refrigerant in which the first pass
P1 to the fourth pass P4 are formed within a plane perpendicular to
the introducing direction of the air A in a meandering manner in
this order from the upper side toward the lower side was
prepared.
[0147] These gas coolers were operated in a refrigeration system,
and the refrigerant flowing positions (distances L in the
refrigerant passages from the inlet), the refrigerant temperature
and the cooling air temperature T were measured. The results are
shown in the graph in FIG. 12.
[0148] In this graph, the black filled square mark denotes the
refrigerant temperature in Example 1, the while blank square mark
denotes the cooling air temperature in Example 1, the black filled
triangle mark denotes the refrigerant temperature in Example 2, the
white blank triangle mark denotes the cooling air temperature in
Example 2, the black filled circle mark denotes the refrigerant
temperature in Comparative Example 1, and the while blank circle
mark denotes the cooling air temperature in Comparative Example
1.
[0149] As will be apparent from this graph, in the gas coolers of
Example 1 and Example 2, the temperature difference between the
refrigerant whose temperature decreases gradually as it travels
along the refrigerant passage and the cooling air could be secured
sufficiently in the entire refrigerant passage (all passes), and
therefore the refrigerant was cooled efficiently.
[0150] To the contrary, in the gas cooler of Comparative Example,
the temperature difference between the refrigerant and the cooling
air varied widely in the refrigerant passage. Especially, at the
refrigerant outlet and therearound, the temperature difference
between the refrigerant and the cooling air became small, and
therefore it was difficult to effectively cool the refrigerant.
[0151] In the gas coolers of Example 1 and Example 2, there was no
gas leakage at the partitioning wall portions in the header tank
and the joint portions between the header tank and the heat
exchanging tubes and no refrigerant mixture.
[0152] The terms and expressions which have been employed herein
are used as terms of description and not of limitation, and there
is no intent, in the use of such terms and expressions, of
excluding any of the equivalents of the features shown and
described or portions thereof, but it is recognized that various
modifications are possible within the scope of the invention
claimed.
INDUSTRIAL APPLICABILITY
[0153] The heat exchanger, the manufacturing method, the tube
connecting structure of a heat exchanger header tank, the gas
cooler using supercritical refrigerant and the refrigerant system
can be employed as, for example, automobile air-conditioners,
household air-conditioners, cooling devices for electric devices
having a refrigeration cycle using CO.sub.2 refrigerant.
* * * * *