U.S. patent application number 12/752663 was filed with the patent office on 2010-07-29 for heat exchanger tube and heat exchanger.
This patent application is currently assigned to SHOWA DENKO K.K.. Invention is credited to Naoki Nishikawa, Noboru Ogasawara, Koichiro Take.
Application Number | 20100186936 12/752663 |
Document ID | / |
Family ID | 18829109 |
Filed Date | 2010-07-29 |
United States Patent
Application |
20100186936 |
Kind Code |
A1 |
Nishikawa; Naoki ; et
al. |
July 29, 2010 |
HEAT EXCHANGER TUBE AND HEAT EXCHANGER
Abstract
A heat exchanger tube (1), wherein a plurality of refrigerant
passages (5) extending in the longitudinal direction of the tube
are formed in a flat tube body (2) with a specified length parallel
with each other in the lateral direction of the tube and, where the
overall cross sectional area of the tube body (2) is (At), the
overall cross sectional area of the refrigerant passage (5) is
(Ac), the outer peripheral length of the tube body (2) is (L), and
the overall inner peripheral length of the refrigerant passage (5)
is (P), set so that the relation of Ac/At.times.100=30 to 55 and
P/L.times.100=150 to 325 can be established, whereby a heat
exchanging performance can be increased.
Inventors: |
Nishikawa; Naoki;
(Oyama-shi, JP) ; Take; Koichiro; (Oyama-shi,
JP) ; Ogasawara; Noboru; (Oyama-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, L.L.P.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SHOWA DENKO K.K.
Tokyo
JP
|
Family ID: |
18829109 |
Appl. No.: |
12/752663 |
Filed: |
April 1, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10432439 |
Oct 29, 2003 |
|
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PCT/JP01/10240 |
Nov 22, 2001 |
|
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12752663 |
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Current U.S.
Class: |
165/173 ;
165/183 |
Current CPC
Class: |
F28D 1/05391 20130101;
F28D 1/0391 20130101; F28F 2250/04 20130101; F28F 1/022 20130101;
F28F 3/025 20130101; F28F 3/04 20130101; F28D 2021/0084
20130101 |
Class at
Publication: |
165/173 ;
165/183 |
International
Class: |
F28F 1/40 20060101
F28F001/40; F28F 9/02 20060101 F28F009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 24, 2000 |
JP |
2000-356968 |
Claims
1. A heat exchanger tube provided with a flat tube main body with a
certain length having a plurality of refrigerant flow passages each
extending in a tube longitudinal direction and disposed in parallel
in a tube widthwise direction, wherein the following relations are
established: Ac/At.times.100=30 to 45; and P/L.times.100=200 to
325, wherein a total cross-sectional area of the tube main body
(including the refrigerant passage portions) is "At"; a total
cross-sectional area of the refrigerant flow passages is "Ac"; an
external peripheral length of the tube main body is "L"; and a
total internal peripheral length of the refrigerant passages is
"P".
2. The heat exchanger tube as recited in claim 1, wherein
Ac/At.times.100 is set to be 35 or more but 40 or less and
P/L.times.100 is 250 or more.
3. The heat exchanger tube as recited in claim 1, wherein the
relation of H=0.5 to 1.5 mm is established, wherein a height of the
tube main body is "H".
4. The heat exchanger tube as recited in claim 1, wherein the
relation of W=10 to 20 mm is established, wherein a width of the
tube main body is "W".
5. The heat exchanger tube as recited in claim 1, wherein the
relation of 5/8<N/W is established, wherein the number of the
refrigerant flow passages is "N" and a width of the tube is
"W".
6. The heat exchanger tube as recited in claim 1, wherein the
relation of Tb.times.1/8<Ta<Tb.times.2/3 is established,
wherein a thickness of a partition wall between the adjacent
refrigerant flow passages in the tube main body is "Ta"; and a
thickness of an external peripheral wall of the tube main body
"Tb".
7. A heat exchanger including a pair of headers disposed in
parallel and a plurality of flat tubes with opposite ends thereof
communicated with the headers, wherein refrigerant introduced via
an refrigerant inlet of the header passes through the flat tubes
while being exchanged heat and flows out of a refrigerant outlet of
the header, wherein the flat tube has a flat tube main body having
a predetermined length and a plurality of refrigerant passages each
extending in the tube longitudinal direction and arranged in
parallel in the tube widthwise direction, and wherein the relations
of Ac/At.times.100=30 to 45 and P/L.times.100=200 to 325 are
established, wherein a total cross-sectional area of the tube main
body (including the refrigerant flow passages) is "At"; a total
cross-sectional area of the refrigerant flow passages is "Ac"; an
external peripheral length of the tube main body is "L"; and a
total peripheral length of the refrigerant flow passages is
"P".
8. A heat exchanger tube including a flat tube main body having a
predetermined length provided with a plurality of refrigerant flow
passages of a rectangular cross-section extending in the tube
longitudinal direction and arranged in parallel in the tube
widthwise direction, wherein the following formulas (f1) to (f4)
are established: 0.5 mm<H<1.5 mm (f1) 5/8<N/W (f2)
R<(H-2Tb).times.1/3 (f3) Tb.times.1/8<Ta<Tb.times.2/3 (f4)
wherein a height of the tube main body is "H"; a width of the tube
main body is "W"; the number of the refrigerant flow passages is
"N"; a curvature radius of a corner portion in a cross-section of
the refrigerant flow passage is "R"; a thickness of an external
peripheral wall of the tube main body is "Tb"; and a thickness of a
partition wall between adjacent refrigerant flow passages in the
tube main body is "Ta".
9. A heat exchanger including a pair of headers disposed in
parallel and a plurality of flat tubes with opposite ends thereof
communicated with the headers, wherein refrigerant introduced via
an refrigerant inlet of the header passes through the flat tubes
while being exchanged heat and flows out of a refrigerant outlet of
the header, wherein the flat tube has a flat tube main body having
a predetermined length and a plurality of refrigerant passages each
extending in the tube longitudinal direction and arranged in
parallel in the tube widthwise direction, and wherein the following
formulas (f1) to (f4) are established: 0.5 mm<H<1.5 mm (f1)
5/8<N/W (f2) R<(H-2Tb).times.1/3 (f3)
Tb.times.1/8<Ta<Tb.times.2/3 (f4) wherein a height of the
tube main body is "H"; a width of the tube main body is "W"; the
number of the refrigerant flow passages is "N"; a curvature radius
of a corner portion in a cross-section of the refrigerant flow
passage is "R"; a thickness of an external peripheral wall of the
tube main body is "Tb"; and a thickness of a partition wall between
adjacent refrigerant flow passages in the tube main body is "Ta".
Description
TECHNICAL FIELD
[0001] The present invention relates to a heat exchanger such as a
condenser for use in a refrigeration cycle for car
air-conditioners, household air-conditioners or cooling devices for
electronics devices and a heat exchanger tube to be applied to such
a heat exchanger.
BACKGROUND ART
[0002] Conventionally, as a condenser for use in a refrigeration
cycle of car air-conditioners, a heat exchanger 50 as shown in
FIGS. 16 and 17 is widely employed.
[0003] This heat exchanger 50 includes a pair of vertically
disposed headers 52 and 52, a plurality of heat exchanger tubes 53
disposed in parallel each other with the opposite ends communicated
with the headers 52 and 52, fins 54 disposed between the adjacent
tubes 53 and at the outside of the outermost tube 53 and side
plates 55 disposed at the outside of the outermost fin 54. The heat
exchanger tubes 53 are grouped into a plurality of passes C1 to C3
by partitioning members 56 provided in the headers 52 and 52. A
gaseous refrigerant introduced via the refrigerant inlet 57
provided at the upper portion of one of the headers 52 passes
through each of the passes C1 to C3 in turn, and is condensed by
exchanging heat with the ambient air while passing through the
passes. The condensed refrigerant flows out through the refrigerant
outlet 58 provided at the lower portion of the other header 52.
[0004] As a tube 53 used for such a heat exchanger 50, an aluminum
extruded tube of a flat shape having a thickness smaller than a
width and a plurality of refrigerant flow passages 53a each having
a rectangular cross-sectional shape and extending in the tube
longitudinal direction is widely used.
[0005] The aforementioned heat exchanger 50 is usually installed in
a vehicle such as a car or a truck. In recent years, such a vehicle
is required to be small in size and light in weight for the purpose
of increasing the fuel economy, decreasing the harmful emission gas
(CO.sub.2, NO.sub.x), decreasing the amount of refrigerant.
Accordingly, all of the automobile parts are also required to be
high in performance as well as small in size and light in weight.
This requirement is also applied to the heat exchanger 50 without
exception.
[0006] In order to decrease the weight of the heat exchanger tube
53, it is considered to decrease the tube height or the thickness
of the peripheral wall of the tube 53.
[0007] However, the passage cross-sectional area of the refrigerant
flow passage 53a decreases as the tube height decreases, causing
increased passage flow resistance and increased pressure loss,
which in turn may sometimes cause deterioration of the condenser
performance.
[0008] Further, if the thickness of the exterior peripheral wall of
the tube 53 is simply formed into a thin wall, the pressure
resistance deteriorates and it becomes difficult to form an enough
sacrifice corrosion resistance layer, which in turn causes
deterioration of corrosion resistance.
[0009] The present invention aims to solve the aforementioned prior
art problems and provide a heat exchanger tube and a heat exchanger
capable of improving the heat exchanging performance while
decreasing the size and weight.
[0010] Another objects of the present invention will be apparent
from the following explanation.
DISCLOSURE OF INVENTION
[0011] The inventors have analyzed a structure of a heat exchanger
such as a condenser, especially a heat exchanger tube adapted to
such a heat exchanger, from all angles in detail, and then
repeatedly performed detailed experiments/studies based on the
analyzed results. As a result, they have found the optimal
conditions of a heat exchanger and its tube capable of attaining
the aforementioned objects, and completed the present
invention.
[0012] According to the first invention, a heat exchanger tube is
provided with a flat tube main body with a certain length having a
plurality of refrigerant flow passages each extending in a tube
longitudinal direction and disposed in parallel with each other in
a tube widthwise direction, wherein the following relations are
established:
[0013] Ac/At.times.100=30 to 55; and
[0014] P/L.times.100=150 to 325,
[0015] wherein a total cross-sectional area of the tube main body
(including the refrigerant flow passage portion) is "At", a total
cross-sectional area of the refrigerant flow passages is "Ac", an
external peripheral length of the tube main body is "L", and a
total internal peripheral length of the refrigerant flow passages
is "P".
[0016] An example of the structure of the heat exchanger tube
according to the present invention will be explained in detail with
reference to the drawings. As shown in FIGS. 1 and 2, the heat
exchanger tube 1 according to the present invention is used as a
heat exchanger tube for a heat exchanger which is similar to a
conventional multi-flow type heat exchanger as shown in FIGS. 16
and 17, and is constituted by an elongated aluminum extruded
article or the like.
[0017] This heat exchanger tube 1 has a flat tube main body 2
having the height H smaller than the width W.
[0018] The tube main body 2 is provided with a plurality of
refrigerant flow passages 5 rectangular in cross-section extending
in the tube longitudinal direction and arranged in the tube
widthwise direction.
[0019] Here, as mentioned above, in the heat exchanger tube 1
according to the present invention, it is necessary to set
"Ac/At.times.100" and "P/L.times.100" to be "30 to 55" and "150 to
325", respectively, as shown in FIG. 5, wherein the total
cross-sectional area of the tube main body 2 (including the
refrigerant flow passage portions) is "At"; the total
cross-sectional area of the refrigerant flow passages is "Ac"; the
external peripheral length of the tube main body 2 is "L"; and the
total internal peripheral length of the refrigerant flow passages 5
is "P".
[0020] That is, in cases where Ac/At is less than 30%, the
refrigerant flow resistance and the pressure loss increase, which
may cause an increased tube weight. To the contrary, in cases where
Ac/At exceeds 55%, the flow passage cross-sectional area increases,
the flow velocity of the refrigerant in the tube decreases and the
heat transfer rate deteriorates. In cases where Ac/At is not larger
than 55%, even if the flow velocity in the tube is low, excellent
heat performance can be obtained by keeping enough tube interior
peripheral length "P".
[0021] Furthermore, in cases where P/L is less than 150%, the heat
transfer performance deteriorates, resulting in insufficient heat
performance as a heat exchanger. In other words, in cases where P/L
is 150% or more, if Ac/At is less than 30%, the refrigerant
pressure loss increases remarkably. However, this increase of
refrigerant pressure loss can be suppressed by setting Ac/At to be
30% or more.
[0022] Furthermore, if P/L is larger than 325%, in case of an
aluminum extruded tube, the extrusion die becomes a minute
configuration, which may cause a problem in manufacturing the tube.
Even if a three-dimensional configuration processing method or a
method of forming communication apertures (refrigerant flow
passages) by roll forming is employed, the die becomes a minute
configuration, which also may cause a problem in manufacturing the
tube.
[0023] Furthermore, in the first invention, in order to obtain the
aforementioned characteristics, it is preferable to employ the
following structure.
[0024] That is, in the first invention, it is preferable to employ
the structure in which Ac/At is set to be 45% or less and P/L is
set to be 200% or more. Furthermore, it is more preferable to
employ the structure in which Ac/At is set to be 35% or more and
40% or less and P/L is set to be 250% or more.
[0025] The specific range of the aforementioned numerals can be
obtained from the graphs shown in FIGS. 6 and 7. That is, the graph
shown in FIG. 6 shows the relation between the "Ac/At" and the heat
transfer quantity "Q" in a tube 1 having a specific "P/L" in a
multi-flow type condenser. FIG. 7 is a graph with hatched lines
showing the range in which enough heat transfer quantity "Q" can be
obtained based on the graph shown in FIG. 6.
[0026] As will be apparent from these graphs, in cases where Ac/At
and P/L fall within the aforementioned essential range or
preferable range, the heat transfer quantity Q is large, which
reveals that the tube falling within the range shown in FIG. 5 has
excellent heat exchanging performance.
[0027] On the other hand, in the first invention, it is preferable
to employ the structure in which the following relation is
established: H=0.5 to 1.5 mm, wherein the height H of the tube main
body 2 is "H".
[0028] That is, as shown in FIGS. 2 and 3, if the tube height H is
set to be 1.5 mm or more, it becomes difficult to decrease the
weight because of the increased size. To the contrary, if the tube
height H is set to be less than 0.5 mm, it becomes difficult to
keep enough height of the refrigerant flow passage 5, causing a
short total peripheral length P of the flow passage. When the tube
height H is set to be less than 0.5 mm by decreasing the thickness
of the external peripheral wall of the tube main body 2 to increase
the size of the refrigerant flow passage 5, there are possibilities
that the pressure resistance of the external peripheral wall
deteriorates or the corrosion resistance deteriorates by failing to
form a sacrifice corrosion layer on the external peripheral
wall.
[0029] Furthermore, in the first invention, it is preferable to
employ the structure in which the relation of W=10 to 20 mm is
established, wherein the width of the aforementioned tube main body
is "W".
[0030] That is, if the width "W" of the tube main body 2 is too
large, the size of the apparatus becomes large. To the contrary, if
the width "W" is too small, there is a fear that it becomes
difficult to keep enough heat transferring characteristic.
[0031] Furthermore, in the present invention, in the refrigerant
flow passage 5 formed in the tube, the heat transfer characteristic
can be increased as the interior peripheral length P increases and
the passage flow resistance can be decreased as the cross-sectional
increases. Accordingly, it is preferable to form the
cross-sectional configuration of the refrigerant flow passage 5 not
into a circular shape but into a rectangular shape (quadrangular
shape) in order to increase the interior peripheral length "P" and
the cross-sectional area.
[0032] As mentioned above, in the present invention, it is
necessary to set the total interior peripheral length of the
refrigerant flow passages to the total tube peripheral length "P/L"
to be larger than a specific value as mentioned above.
[0033] In order to increase "P/L" or to set "P/L" to be 150% or
more, it is considered to employ a method for increasing the number
of refrigerant flow passages 5 to the unit tube width "N/W" and a
method for forming protruded micro fins 5a on the interior surface
of the refrigerant flow pass 5 as shown in FIGS. 8A to 8C without
increasing the number of refrigerant flow passages.
[0034] FIG. 8A shows an embodiment in which each refrigerant flow
passage 5 is integrally provided with a total of two micro fins 5a,
one on the upper wall surface and one on the lower wall surface,
extending in the passage longitudinal direction. FIG. 8B shows an
embodiment in which each refrigerant flow passage 5 is integrally
provided with a total of four micro fins 5a, two on the upper wall
surface and two on the lower wall surface. FIG. 8C shows an
embodiment in which each refrigerant flow passage 5 is integrally
provided with a total of six micro fins 5a, three on the upper wall
surface and three on the lower wall surface.
[0035] Furthermore, in the first invention, if the number of the
refrigerant flow passages 5 to the tube width "N/W" decreases too
much, the number of partition walls 4 decreases, which in turn may
cause deterioration of the pressure resistance. Therefore, it is
necessary to set "N/W" to be larger than 5/8.
[0036] That is, in the first invention, it is preferable to employ
the structure in which the relation of 5/8<N/W is established,
wherein the number of the aforementioned refrigerant flow passages
is "N" and the tube width is "W".
[0037] Furthermore, in the first invention, although the
refrigerant flow passage 5 has a rectangular cross-section as
mentioned above, in cases where the passage height "H-2Tb" is very
small, even if the curvature radius of the portion of the tube
forming die corresponding to the corner portion of the refrigerant
flow passage 5 is set to be "0 (zero)", the corner portion of the
refrigerant flow passage 5 is formed into a gentle arc-shape due to
the influence of the metal flow at the time of extrusion. This may
sometimes cause an excessive radius "R" relative to the passage 5.
Concretely, as shown in FIG. 4, in cases where the tube height
"H-2Tb" is small as shown in FIG. 4, the corner portions of the
upper and lower regions T1 and T3 among the trisected regions T1 to
T3 of the passage height are formed into gentle arc-shape,
respectively, which sometimes causes an insufficient internal
peripheral length "P" or insufficient passage cross-sectional area.
Accordingly, in the present invention, it is preferable that the
curvature radius "R" of the corner portion of the refrigerant flow
passage 5 is formed to be larger than one third (1/3) of the
passage height "H-2Tb".
[0038] That is, in the first invention, it is more preferable to
employ the structure in which the relation of
R<(H-2Tb).times.1/3 is established, wherein the curvature radius
of the corner portion in the cross-section of the refrigerant flow
passage is "R", the height of the aforementioned tube main body is
"H" and the thickness of the external peripheral wall of the tube
main body is "Tb".
[0039] Furthermore, in the first invention, it is more preferable
to employ the structure in which the relation of
Tb.times.1/8<Ta<Tb.times.2/3 is established, wherein the
thickness of the partition wall between the adjacent refrigerant
flow passages in the tube main body is "Ta", and the thickness of
the external peripheral wall of the tube main body is "Tb".
[0040] That is, as shown in FIG. 3, although it is necessary to set
the partition wall thickness "Ta" to be more than a certain
thickness, even if the partition wall thickness "Ta" is increased
more than necessary, the pressure resistance does not improve
because of the following reasons. When inner pressure is applied to
the refrigerant flow passage 5, if the partition wall thickness
"Ta" is substantially thinner than the external peripheral wall
thickness "Tb", the partition wall 4 will be destroyed. To the
contrary, if the partition wall thickness "Ta" is substantially
thicker than the external peripheral wall thickness "Tb", the
external peripheral wall 3 will be destroyed. In view of the above
information, taking into account that the maximum thickness of the
sacrifice corrosion layer of the external peripheral wall 3 formed
by zinc diffusion is about 33.3% (2/3) of the external peripheral
wall thickness "Tb", the pressure resistance would not improve even
if the relation of "Ta.gtoreq.Tb.times.2/3" is established.
Accordingly, it is preferable to set the upper limit of the
partition wall thickness "Ta" to be smaller than
"Tb.times.2/3".
[0041] Furthermore, in cases where the partition wall thickness Ta
is too thin, the strength of the partition wall 4 may deteriorates,
which in turn may deteriorate the pressure resistance of the tube.
Therefore, it is preferable that the partition wall thickness Ta is
set to be larger than one eighth (1/8) of the external peripheral
wall thickness Tb.
[0042] Accordingly, in the present invention, it is preferable that
the relation of "Tb.times.1/8<Ta<Tb.times.2/3" is established
as mentioned above.
[0043] Furthermore, in the present invention, it is more preferable
to employ the structure in which the mass velocity of the
refrigerant passing through the refrigerant flow passage is set to
be 50 to 800 kg/m.sup.2 sec.
[0044] That is, in cases where this structure is employed, the heat
transfer rate can be improved, resulting in excellent heat
exchanging performance.
[0045] In the present invention, it is possible to employ the
structure in which the tube main body is composed of a tube
external peripheral wall member constituting the external
peripheral wall and an inner plate inserted in the external
peripheral wall member to form refrigerant flow passages.
[0046] For example, the heat exchanger tube 11 as shown in FIGS. 9
and 10 can be preferably used. In the heat exchanger tube 11, a
plurality of refrigerant flow passages 15 are provided side by
side, and a plurality of communication apertures 14c communicating
with adjacent refrigerant flow passages are formed. In this tube
11, since the refrigerant comes and goes adjacent passages freely,
heat exchanging can be performed in a balanced manner in the entire
tube widthwise direction, which further improves the heat
exchanging performance.
[0047] Furthermore, FIG. 11 shows a heat exchanger tube 21. The
tube main body 22 includes a tube external peripheral wall member
22a constituting the external peripheral wall and a wavy inner
plate 22b to be inserted into the tube external peripheral wall
member 22a. The inner plate 22b constitutes partition walls and
inner fins and forms the refrigerant flow passages 25 within the
tube.
[0048] Furthermore, in the present invention, it is possible to
employ the structure in which the tube main body includes a tube
upper side member constituting the upper side of the tube main
body, a tube lower side member constituting the lower side thereof
and a partition plate disposed between the upper and lower side
members, wherein the partitioning plate partitions each refrigerant
flow passage into upper and lower portions to thereby form a multi
layer structure.
[0049] For example, as shown in FIG. 12, the heat exchanger tube 31
includes a tube upper side member 32a constituting the upper side
of the tube, a tube lower side member 32b constituting the lower
side of the tube and a partition plate 32c disposed between the
upper and lower side members 32a and 32b. Thus, the multi-layer
(two layers) refrigerant flow passages 35 each partitioned into an
upper portion and a lower portion are arranged in parallel in the
tube widthwise direction. It is also possible to form a refrigerant
flow passage of a multi-layer structure having three or more layers
by disposing two or more partition plates 32c.
[0050] Furthermore, in the present invention, it is also possible
to employ a heat exchanger tube whose tube main body is made of a
press formed article.
[0051] As shown FIG. 13, such a heat exchanger tube 41 made of a
press formed article can be obtained by bending a metal plate into
a flat tube shape and forming partition walls 44 forming
refrigerant flow passages 45 in the tube.
[0052] In the heat exchanger tubes according to modified
embodiments shown in FIGS. 9 to 13, the same or corresponding
reference numerals are allotted to the same or corresponding
portion of the tube shown in FIGS. 1 to 3.
[0053] On the other hand, the second invention specifies the heat
exchanger such as a condenser using the heat exchanger tube of the
first invention.
[0054] That is, according to the second invention, a heat exchanger
includes a pair of headers disposed in parallel and a plurality of
flat tubes with opposite ends thereof communicated with the
headers, wherein refrigerant introduced via an refrigerant inlet of
the header passes through the flat tubes while being exchanged heat
and flows out of a refrigerant outlet of the header, wherein the
flat tube has a flat tube main body having a predetermined length
and a plurality of refrigerant flow passages each extending in the
tube longitudinal direction and arranged in parallel in the tube
widthwise direction, and wherein the relations of
"Ac/At.times.100=30 to 55" and "P/L.times.100=150 to 325" are
established, wherein the total cross-sectional area of the tube
main body (including the refrigerant flow passages) is "At"; the
total cross-sectional area of the refrigerant flow passages is
"Ac"; the external peripheral length of the tube main body is "L"
and the total peripheral length of the refrigerant flow passages is
"P".
[0055] Since the heat exchanger of the second invention specifies
the heat exchanger using the heat exchanger tube of the first
invention, the same functions and effects as mentioned above can be
obtained.
[0056] On the other hand, the present inventors eagerly conducted
detailed experiences and studies based on the aforementioned first
invention and further found appropriate constitutional
elements.
[0057] As a result, according to the third invention, a heat
exchanger tube includes a flat tube main body having a
predetermined length provided with a plurality of refrigerant flow
passages of a rectangular cross-section extending in the tube
longitudinal direction and arranged in parallel in the tube
widthwise direction, wherein the following formulas are
established:
0.5 mm<H<1.5 mm (f1)
5/8<N/W (f2)
R<(H-2Tb).times.1/3 (f3)
Tb.times.1/8<Ta<Tb.times.2/3 (f4)
[0058] wherein the height of tube main body is "H"; the width of
tube main body is "W"; the number of the refrigerant flow passages
is "N"; the curvature radius of the corner portion in the
cross-section of the refrigerant flow passage is "R"; the thickness
of the external peripheral wall of the tube main body is "Tb"; and
the thickness of the partition wall between the adjacent
refrigerant flow passages in the tube main body is "Ta".
[0059] These formulas (f1) to (f4) have been explained in the first
invention, and the heat exchanger tube of the third invention
satisfying all of these formulas (f1) to (f4) is excellent in heat
exchanging performance because of the reasons mentioned above.
[0060] Furthermore, in the third invention, in order to improve the
heat transfer rate, it is preferable to employ the structure in
which the mass velocity of the refrigerant passing through the
refrigerant flow passage is set to be 50 to 800 kg/m.sup.2 sec.
[0061] On the other hand, the fourth invention specifies the heat
exchanger such as a condenser using the heat exchanger tube of the
third invention.
[0062] That is, according to the fourth invention, a heat exchanger
includes a pair of headers disposed in parallel and a plurality of
flat tubes with opposite ends thereof communicated with the
headers, wherein refrigerant introduced via an refrigerant inlet of
the header passes through the flat tubes while being exchanged heat
and flows out of a refrigerant outlet of the header, wherein the
flat tube has a flat tube main body having a predetermined length
and a plurality of refrigerant flow passages each extending in the
tube longitudinal direction and arranged in parallel in the tube
widthwise direction, and wherein the following formulas are
established:
0.5 mm<H<1.5 mm (f1)
5/8<N/W (f2)
R<(H-2Tb).times.1/3 (f3)
Tb.times.1/8<Ta<Tb.times.2/3 (f4)
[0063] wherein the height of tube main body is "H"; the width of
tube main body is "W"; the number of the refrigerant flow passages
is "N"; the curvature radius of the corner portion in the
cross-section of the refrigerant flow passage is "R"; the thickness
of the external peripheral wall of the tube main body is "Tb"; and
the thickness of the partition wall between the adjacent
refrigerant flow passages in the tube main body is "Ta".
[0064] Since this fourth invention specifies the heat exchanger
using the heat exchanger tubes of the third invention, the same
functions and effects as mentioned above can be obtained.
[0065] Furthermore, in the fourth invention, in order to improve
the heat transfer rate, it is preferable to employ the structure in
which the mass velocity of the refrigerant passing through the
refrigerant flow passage is set to be 50 to 800 kg/m.sup.2 sec.
BRIEF DESCRIPTION OF DRAWINGS
[0066] FIG. 1 is a perspective view showing the heat exchanger tube
related to the invention.
[0067] FIG. 2 is a cross-sectional view showing the heat exchanger
tube related to the invention.
[0068] FIG. 3 is an enlarged cross-sectional view showing the
refrigerant flow passage and its vicinity of the heat exchanger
tube related to the invention.
[0069] FIG. 4 is an enlarged cross-sectional view showing the
refrigerant flow passage and its vicinity of a preferable
embodiment of the heat exchanger tube according to the
invention.
[0070] FIG. 5 is a graph showing the relation between Ac/At and P/L
in a heat exchanger tube of a multi-flow condenser.
[0071] FIG. 6 is a graph showing the relation between Ac/At and the
heat transfer quantity in the heat exchanger tube.
[0072] FIG. 7 is a graph showing the applicable range of Ac/At and
P/L in the heat exchanger tube according to the invention.
[0073] FIG. 8A is an enlarged cross-sectional view showing the
refrigerant flow passage and its vicinity of the heat exchanger
tube of the first modification of the invention.
[0074] FIG. 8B is an enlarged cross-sectional view showing the
refrigerant flow passage and its vicinity of the heat exchanger
tube of the second modification of the invention.
[0075] FIG. 8C is an enlarged cross-sectional view showing the
refrigerant flow passage and its vicinity of the heat exchanger
tube of the third modification of the invention.
[0076] FIG. 9 is an exploded perspective view showing the heat
exchanger tube of the fourth modification of the invention.
[0077] FIG. 10A is a side cross-sectional view showing the heat
exchanger tube of the fourth modification of the invention.
[0078] FIG. 10B is a front cross-sectional view showing the heat
exchanger tube of the fourth modification of the invention.
[0079] FIG. 11 is a perspective view showing the heat exchanger
tube of the fifth modification of the invention.
[0080] FIG. 12 is an exploded perspective view showing the heat
exchanger tube of the sixth modification of the invention.
[0081] FIG. 13 is a perspective view showing the heat exchanger
tube of the seventh modification of the invention.
[0082] FIG. 14 is a graph showing the relation between the heat
transfer and P/W in the heat exchanger tube of the example and
comparative example.
[0083] FIG. 15 is a graph showing the relation between the
breakdown pressure and the partition wall thickness in the heat
exchanger tube of the example and comparative example.
[0084] FIG. 16 is a front view showing the condenser for a car
air-conditioner.
[0085] FIG. 17 is an exploded perspective view showing the
principle portion of the condenser for a car air-conditioner.
BEST MODE FOR CARRYING OUT THE INVENTION
Examples
[0086] Hereinafter, examples and comparative examples related to
the invention will be detailed.
TABLE-US-00001 TABLE 1 Ac At P L Ac/At P/L N H W Q Ta Tb R ha
(mm.sup.2) (mm.sup.2) (mm) (mm) (%) (%) (number) (mm) (mm) (kW) P/W
N/W (mm) (mm) (mm) (kW/K) Example 1 6.5 18.1 104 32.1 35.8 325 35
1.15 16 10.8 6.5 2.18 0.06 0.25 0.05 0.98 2 8 18.1 71 32.1 44.2 223
20 1.15 16 10.1 4.46 1.25 0.06 0.25 0.05 0.52 3 8.8 18.1 53 32.1
48.6 166 12 1.15 16 10 3.32 0.75 0.06 0.25 0.05 0.3 4 6.5 18.1 104
32.1 35.8 325 35 1.15 16 10.8 6.5 2.18 0.06 0.25 0.05 0.98 5 5.8
18.1 103 32.1 32.1 320 35 1.15 16 10.4 6.4 2.18 0.09 0.25 0.05 0.9
6 5.4 18.1 101 32.1 30 315 35 1.15 16 10.2 6.3 2.18 0.12 0.25 0.05
0.8 Comparative 1 9 18.1 43.2 32.1 50 134 7 1.15 16 9.4 2.7 0.43
0.12 0.25 0.05 0.22 Example 2 9.2 18.1 38.9 32.1 50 121 5 1.15 16
9.5 2.43 0.31 0.12 0.25 0.05 0.2 3 7.4 18.1 108 32.1 41 336 35 1.15
16 10.6 6.75 2.18 0.03 0.25 0.05 -- 4 4.31 18.1 98.4 32.1 23 307 35
1.15 16 9.65 6.15 2.18 0.17 0.25 0.05 -- Ac: Total cross-sectional
area of the refrigerant flow passages At: Total cross-sectional
area of the tube main body P: Total interior peripheral length of
the refrigerant flow passages L: Exterior peripheral length of the
tube main body N: Number of refrigerant flow passages H: Height of
tube main body W: Width of tube main body Ta: Thickness of the
partition wall Tb: Thickness of the external peripheral wall R:
Curvature radius of the corner portion of the refrigerant flow
passage Q: Heat transfer quantity (kW) ha: Heat transfer rate
(kW/K)
Example 1
[0087] As shown in Table 1, a heat exchanger tube in which the
total cross-sectional area of the refrigerant flow passages Ac was
6.5 mm.sup.2, the total cross-sectional area of the tube main body
was 18.1 mm.sup.2, Ac/At was 35.8%, P/L was 325%, the total
interior peripheral length of the refrigerant flow passages P was
104 mm, the external peripheral length of the tube main body was
32.1 mm, the number of refrigerant flow passages was 35, the tube
main body height H was 1.15 mm, the tube main body width W was 16
mm, the partition wall thickness Ta was 0.06 mm, the thickness of
the external peripheral wall Tb was 0.25 mm and the curvature
radius R of the refrigerant flow passage was 0.05 mm, was
prepared.
[0088] A multi-flow type condenser shown in FIGS. 16 and 17 was
formed by using the heat exchanger tubes, and the heat performance
Q and the heat transfer ha were measured.
TABLE-US-00002 TABLE 2 Ac At P L Ac/At P/L N H W Q Ta Tb R ha
(mm.sup.2) (mm.sup.2) (mm) (mm) (%) (%) (number) (mm) (mm) (kW) P/W
N/W (mm) (mm) (mm) (kW/K) Example 7 8 18.1 71 32.1 44.2 223 20 1.15
16 10.1 4.46 1.25 0.06 0.25 0.05 0.52 8 8.8 18.1 53 32.1 48.6 166
12 1.15 16 10 3.32 0.75 0.06 0.25 0.05 0.3 9 6.5 18.1 104 32.1 35.8
325 35 1.15 16 10.8 6.5 2.18 0.06 0.25 0.05 0.98 10 5.8 18.1 103
32.1 32.1 320 35 1.15 16 10.4 6.4 2.18 0.09 0.25 0.05 0.9 11 5.4
18.1 101 32.1 30 315 35 1.15 16 10.2 6.3 2.18 0.12 0.25 0.05 0.8
Comparative 5 9.2 18.1 38.9 32.1 50 121 5 1.15 16 9.5 2.43 0.31
0.12 0.25 0.05 0.2 Example 6 11.1 18.1 80.6 32.1 61 251 20 1.15 16
9.75 5.04 1.25 0.07 0.18 0.05 -- 7 4.31 18.1 98.4 32.1 23 307 35
1.15 16 9.65 6.15 2.18 0.17 0.25 0.05 -- Ac: Total cross-sectional
area of the refrigerant flow passages At: Total cross-sectional
area of the tube main body P: Total interior peripheral length of
the refrigerant flow passages L: Exterior peripheral length of the
tube main body N: Number of refrigerant, flow passages H: Height of
tube main body W: Width of tube main body Ta: thickness of the
partition wall Tb: Thickness of the external peripheral wall R:
Curvature radius of the corner portion of the refrigerant flow
passage Q: Heat transfer quantity (kW) ha: Heat transfer rate
(kW/K)
Examples 2-11, Comparative Examples 1-7
[0089] In the same manner as in the aforementioned Example,
Condensers were formed by using the heat exchangers shown in Tables
1 and 2, and measurements were performed in the same manner.
[0090] As shown in Tables 1 and 2, in the heat exchanger related to
the present invention, they are excellent in heat transfer and in
heat performance.
<Evaluation of Heat Performance>
[0091] In each condenser of the aforementioned Examples 1-3 and
Comparative Examples 1 and 2, the relation between P/W and the heat
transfer ha is shown in the graph shown in FIG. 14. In the graph
shown in FIG. 14, Examples 1-3 are shown by A1 to A3, and
Comparative Examples 1 and 2 are shown by B1 and B2,
respectively.
<Evaluation of Pressure Resistance>
[0092] Inner pressure was applied to each condenser of Examples 4-6
and Comparative Examples 3 and 4, and the burst pressure [MPa] was
measured. In each heat exchanger tube, the aforementioned
measurement was performed in the state in which zinc diffusion
layer (sacrifice corrosion layer) was removed.
[0093] The measured results were shown in the graph in FIG. 15 and
Table 3 shown below. In the graph in FIG. 15, Examples 4-6 are
shown by A4-A6, respectively, and Comparative Examples 4 and 5 are
shown by B4 and B5, respectively.
TABLE-US-00003 TABLE 3 Ta [mm] Burst pressure [MPa] Example 4 0.06
11.3 Example 5 0.09 13.5 Example 6 0.12 16.5 Comparative Example 3
0.03 5.4 Comparative Example 4 0.17 16.5
[0094] This application claims priority to Japanese Patent
Application No. 2000-356968 filed on Nov. 24, 2000, the disclosure
of which is incorporated by reference in its entirety.
[0095] 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
[0096] As mentioned above, according to the heat exchanger tube of
the present invention and the heat exchanger using the tubes, it is
possible to reduce the weight and improve the heat exchanging
performance. Therefore, they are preferably used for a
refrigeration system especially as a car air-conditioning
refrigeration system.
* * * * *