U.S. patent application number 16/439871 was filed with the patent office on 2019-12-19 for heat exchanger for liquid immersion cooling.
This patent application is currently assigned to FUJITSU LIMITED. The applicant listed for this patent is FUJITSU LIMITED. Invention is credited to Michimasa AOKI, Masumi SUZUKI, Keizou Takemura.
Application Number | 20190383559 16/439871 |
Document ID | / |
Family ID | 68839783 |
Filed Date | 2019-12-19 |
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United States Patent
Application |
20190383559 |
Kind Code |
A1 |
AOKI; Michimasa ; et
al. |
December 19, 2019 |
HEAT EXCHANGER FOR LIQUID IMMERSION COOLING
Abstract
A heat exchanger for liquid immersion cooling includes a first
coolant stored in a tank capable of accommodating an electronic
component, and configured to cool the electronic component by
immersion, an introduction pipe into which a second coolant is
introduced from outside of the tank, a discharge pipe from which
the second coolant is discharged to outside of the tank, and a
plurality of connection pipes coupled between the introduction pipe
and the discharge pipe and configured to flow the second coolant
from the introduction pipe to the discharge pipe, wherein the heat
exchanger is immersed in the first coolant and accommodated in the
tank.
Inventors: |
AOKI; Michimasa; (Kawasaki,
JP) ; SUZUKI; Masumi; (Kawasaki, JP) ;
Takemura; Keizou; (Kawasaki, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FUJITSU LIMITED |
Kawasaki-shi |
|
JP |
|
|
Assignee: |
FUJITSU LIMITED
Kawasaki-shi
JP
|
Family ID: |
68839783 |
Appl. No.: |
16/439871 |
Filed: |
June 13, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F28D 1/0213 20130101;
F28D 1/05366 20130101; F28D 1/05316 20130101; H05K 7/20236
20130101; F28D 1/0435 20130101; F28D 1/05383 20130101; F28D
2021/0028 20130101; H05K 7/20772 20130101; G06F 1/20 20130101; G06F
2200/201 20130101 |
International
Class: |
F28D 1/053 20060101
F28D001/053; F28D 1/02 20060101 F28D001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 18, 2018 |
JP |
2018-115355 |
Claims
1. A heat exchanger for liquid immersion cooling comprising: a
first coolant stored in a tank capable of accommodating an
electronic component, and configured to cool the electronic
component by immersion; an introduction pipe into which a second
coolant is introduced from outside of the tank; a discharge pipe
from which the second coolant is discharged to outside of the tank;
and a plurality of connection pipes coupled between the
introduction pipe and the discharge pipe and configured to flow the
second coolant from the introduction pipe to the discharge pipe,
wherein the heat exchanger is immersed in the first coolant and
accommodated in the tank.
2. The heat exchanger according to claim 1, wherein the plurality
of connection pipes is arranged side by side in a plurality of rows
in a direction intersecting a direction of gravity, arranged side
by side in a plurality of stages in the direction of gravity.
3. The heat exchanger according to claim 1, wherein the plurality
of connection pipes is arranged side by side in three rows or more
in the direction intersecting the direction of gravity.
4. The heat exchanger according to claim 1, wherein the plurality
of connection pipes have a cross-sectional shape having a
longitudinal direction and a lateral direction, the direction of
gravity is the longitudinal direction, the direction intersecting
the direction of gravity is the lateral direction, and the
plurality connection pipes are arranged side by side in a plurality
of rows in the direction intersecting the direction of gravity and
arranged side by side in a plurality of stages in the direction of
gravity.
5. The heat exchanger according to claim 1, wherein an interior of
each of the plurality of connection pipes is partitioned into a
plurality of spaces.
6. The heat exchanger according to claim 1, wherein the plurality
of connection pipes are arranged so as to be shifted with respect
to the electronic component in a direction intersecting the
direction of gravity.
7. The heat exchanger according to claim 1, wherein the first
coolant and the second coolant are same type of coolant.
8. The heat exchanger according to claim 1, wherein the first
coolant and the second coolant are different types of coolant.
9. The heat exchanger according to claim 8, wherein the first
coolant is a fluorine-based insulating coolant and the second
coolant is water or a propylene glycol coolant.
10. A heat exchanger system comprising: a tank storing a first
coolant to cool an electronic component by immersion; and an heat
exchanger immersed in the first coolant, the heat exchanger
including an introduction pipe through which a second coolant flows
from outside the tank; a discharge pipe through which the second
coolant flows to outside of the tank; and a plurality of connection
pipes through which the second coolant flows from the introduction
pipe to the discharge pipe, the plurality of connection pipes being
coupled between the introduction pipe and the discharge pipe and
arranged in a plurality of stages of two or more connection pipes
located side by side in a direction extending perpendicular to the
introduction pipe and the discharge pipe, and each of the plurality
of stages of two or more connection pipes arranged in a direction
extending parallel to the introduction pipe and the discharge
pipe.
11. The heat exchanger system according to claim 10, wherein an
interior of each of the plurality of connection pipes is
partitioned into a plurality of spaces.
12. The heat exchanger system according to claim 10, further
comprising: a transfer pipe connecting a portion of the
introduction pipe located outside of the tank to a portion of the
discharge pipe located outside of the tank.
13. The heat exchanger system according to claim 12, further
comprising: a pump connected to a portion of the transfer pipe, and
an external heat exchanger connected to a portion of the transfer
pipe, wherein the pump circulates the second coolant between the
heat exchanger and the external heat exchanger via the transfer
pipe.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
priority of the prior Japanese Patent Application No. 2018-115355,
filed on Jun. 18, 2018, the entire contents of which are
incorporated herein by reference.
FIELD
[0002] This application relates to a heat exchanger for liquid
immersion cooling.
BACKGROUND
[0003] As a method for cooling electronic components, an immersion
cooling method is known in which electronic components are immersed
in a cooling liquid that is stored in a main tank body and cooled.
In the liquid immersion cooling method, in some cases a heat
exchanger for cooling the cooling liquid is immersed in the cooling
liquid in order to suppress a deterioration in the cooling effect
on electronic components due to a rise in the temperature of the
cooling liquid in which the electronic components are immersed.
However, even in a case where the heat exchanger is immersed in the
cooling liquid, convection does not occur in the cooling liquid
stored in the main tank body, and the cooling effect on the
electronic components may not be improved in some cases. Therefore,
by using a heat exchanger having a coolant elevating hole and a
coolant descending hole, and providing a heat insulating member on
the inner surface of the coolant elevating hole arranged directly
above a heat generating member, convection of the cooling liquid is
generated (For example, refer to Japanese Laid-open Patent
Publication No. 3-50897).
SUMMARY
[0004] According to an aspect of the embodiments, a heat exchanger
for liquid immersion cooling includes a first coolant stored in a
tank capable of accommodating an electronic component, and
configured to cool the electronic component by immersion, an
introduction pipe into which a second coolant is introduced from
outside of the tank, a discharge pipe from which the second coolant
is discharged to outside of the tank, and a plurality of connection
pipes coupled between the introduction pipe and the discharge pipe
and configured to flow the second coolant from the introduction
pipe to the discharge pipe, wherein the heat exchanger is immersed
in the first coolant and accommodated in the tank.
[0005] The object and advantages of the invention will be realized
and attained by means of the elements and combinations particularly
pointed out in the claims.
[0006] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are not restrictive of the invention.
BRIEF DESCRIPTION OF DRAWINGS
[0007] FIG. 1A is a see-through front view of an immersion tank
according to a first embodiment, and FIG. 1B is a cross-sectional
view taken along a line IB-IB of FIG. 1A;
[0008] FIG. 2A is a front view of a heat exchanger, and FIG. 2B is
a bottom view;
[0009] FIG. 3A is a perspective view of the heat exchanger, and
FIG. 3B is a cross-sectional view taken along a line IIIB-IIIB of
FIG. 2A;
[0010] FIG. 4 is a see-through front view of an immersion tank
according to a comparative example;
[0011] FIG. 5 is a cross-sectional view for explaining the effect
of the immersion tank according to the first embodiment; and
[0012] FIG. 6A is a see-through front view of an immersion tank
according to a second embodiment, and FIG. 6B is a cross-sectional
view taken along a line VIB-VIB of FIG. 6A.
DESCRIPTION OF EMBODIMENTS
[0013] The method described in Japanese Laid-open Patent
Publication No. 3-50897 leaves room for improvement from the aspect
of improving the cooling performance by generating convection in
the liquid coolant stored in the main tank body.
[0014] Hereinafter, embodiments will be described with reference to
the drawings.
First Embodiment
[0015] FIG. 1A is a see-through front view of an immersion tank
according to a first embodiment, and FIG. 1B is a cross-sectional
view taken along a line IB-IB of FIG. 1A. As illustrated in FIG. 1A
and FIG. 1B, an immersion tank 100 of the first embodiment includes
a main tank body 10 and a heat exchanger 30 for liquid immersion
cooling. The main tank body 10 has a space 12 inside. In the space
12, a coolant 14 is stored. The coolant 14 is a coolant having an
electrical insulating property and thermal conductivity. The
coolant 14 is a fluorine-based insulating coolant such as a
fluorocarbon-based coolant, for example. The main tank body 10 is
formed of plastic or stainless steel, for example.
[0016] In the main tank body 10, a wiring board 70 on which
electronic components 60, 62, and 64 are mounted is accommodated
while being immersed in the coolant 14. Since the coolant 14 has
electrical insulating properties, the wiring board 70 on which the
electronic components 60, 62, and 64 are mounted may be cooled by
immersing in the coolant 14. The electronic component 60 is, for
example, a central processing unit (CPU). The electronic components
62 and 64 are, for example, memories. The wiring board 70 is, for
example, a printed wiring board. A heat sink 72 having a plurality
of radiation fins may be provided on the main surface of the
electronic component 60. As a result, the heat radiation area of
the electronic component 60 is increased, so the electronic
component 60 is effectively cooled. The heat sink 72 is formed of a
material having a high thermal conductivity such as metal or the
like, and is formed of, for example, aluminum.
[0017] The heat exchanger 30 is accommodated in the main tank body
10 and immersed in the coolant 14. The heat exchanger 30 is
provided for cooling the coolant 14 stored in the main tank body
10. The heat exchanger 30 has an introduction pipe 32, a discharge
pipe 34, and a plurality of connecting pipes 36 connecting between
the introduction pipe 32 and the discharge pipe 34. The
introduction pipe 32, the discharge pipe 34, and the connecting
pipes 36 are formed of a material having high thermal conductivity
such as metal or the like. As an example, the introduction pipe 32,
the discharge pipe 34, and the connecting pipes 36 are formed of
aluminum. The introduction pipe 32, the discharge pipe 34, and the
connecting pipes 36 are not limited to a case where they are formed
of the same material, and may be formed of different materials.
[0018] One each of the introduction pipe 32 and the discharge pipe
34 may be provided, however in the first embodiment, a case where a
plurality of pipes is provided will be described as an example. The
plurality of introduction pipes 32 is connected to a common
introduction part 40 having one introduction port 38. The plurality
of discharge pipes 34 is connected to a common discharge part 44
having one discharge port 42. The introduction port 38 and the
discharge port 42 are connected to an external heat exchanger 52
such as a chiller or the like via a pipe 50 (e.g., a "transfer
pipe"). A pump 54 is installed in the pipe 50.
[0019] A coolant (hereinafter referred to as circulating coolant)
is sealed in the heat exchanger 30. When the pump 54 is driven,
circulating coolant circulates between the heat exchanger 30 and
the external heat exchanger 52. The heat exchanger 30 is immersed
in the coolant 14 stored in the main tank body 10, so the
circulating coolant flows in the heat exchanger 30, heat exchange
occurs with the coolant 14, and the coolant 14 is cooled.
[0020] The introduction pipes 32 and the discharge pipes 34 extend
perpendicular to the bottom surface of the main tank body 10, for
example. The plurality of connecting pipes 36 extends in parallel
to the bottom surface of the main tank body 10, for example. The
term "extending perpendicular" is not limited to the case where the
pipes extend completely perpendicularly to the bottom surface of
the main tank body 10, and even a case where the pipes extend with
a slight inclination with respect to the bottom surface of the main
tank body 10 is included. Similarly, "extending in parallel" is not
limited to the case where the pipes extend completely in parallel
to the bottom surface of the main tank body 10, and even a case
where the pipes extend with a slight inclination with respect to
the bottom surface of the main tank body 10 is also included. In
the first embodiment, the introduction pipes 32 and the discharge
pipes 34 extend in the direction of gravity, and the plurality of
connecting pipes 36 extends in the first intersecting direction
intersecting (for example orthogonal to) the direction of
gravity.
[0021] Here, the heat exchanger 30 will be described by using FIG.
2A to FIG. 3B together. FIG. 2A is a front view of the heat
exchanger, and FIG. 2B is a bottom view. FIG. 3A is a perspective
view of the heat exchanger, and FIG. 3B is a cross-sectional view
taken along a line IIIB-IIIB of FIG. 2A. In FIG. 2B, the
introduction pipes 32 and the discharge pipes 34 are illustrated
while seeing through a part of the member. In FIG. 3A, the flow of
the circulating coolant flowing through the heat exchanger 30 is
indicated by arrows. The circulating coolant may be of the same
type as the coolant 14 stored in the main tank body 10 or may be of
a different type.
[0022] The plurality of introduction pipes 32 is in close proximity
to each other and extend in parallel to each other in the gravity
direction. The plurality of discharge pipes 34 is in close
proximity to each other and extend in parallel to each other in the
gravity direction. The plurality of connecting pipes 36 is
connected between the introduction pipes 32 and the discharge pipes
34 and extend in the first intersecting direction intersecting the
direction of gravity. For example, the plurality of connecting
pipes 36 is such that the cross-sectional shape when cut in the
direction of gravity is a flat shape whose longitudinal direction
is the direction of gravity, however, may also be another shape
such as a circular shape or the like The plurality of connecting
pipes 36 is arranged in a plurality of rows in the second
intersecting direction, with the second intersecting direction
intersecting (for example orthogonal to) the direction of gravity
and the first intersecting direction being the lateral direction of
the flat shape. In addition, the plurality of connecting pipes 36
is arranged side by side in a plurality of stages also in the
direction of gravity. Providing the plurality of connecting pipes
36 side by side in a plurality of stages in the direction of
gravity is not limited to a case where the pipes are provided side
by side in a plurality of stages completely in parallel to the
direction of gravity, and a case of providing the pipes side by
side in a plurality of stages that are slightly inclined with
respect to the direction of gravity is also included. The width W
in the lateral direction of the connecting pipes 36 is, for
example, about 4 mm, and the length L in the longitudinal direction
is, for example, about 45 mm. An interval D1 between the connecting
pipes 36 arranged side by side in a plurality of rows is, for
example, about 6 mm, and an interval D2 between the connecting
pipes 36 arranged side by side in a plurality of stages is, for
example, about 10 mm.
[0023] The connecting pipes 36 arranged side by side in a plurality
of rows in the second intersecting direction are respectively
connected between different introduction pipes 32 among the
plurality of introduction pipes 32 and different discharge pipes 34
among the plurality of discharge pipes 34. For example, one of the
plurality of rows in which the connecting pipes 36 are arranged is
connected between one of the plurality of introduction pipes 32 and
one of the plurality of discharge pipes 34. Another one of the
plurality of rows of connecting pipes 36 is connected between
another one of the plurality of introduction pipes 32 and another
one of the plurality of discharge pipes 34.
[0024] The inside of a connecting pipe 36 is partitioned into a
plurality of spaces 46, and a plurality of flow paths is formed.
The circulating coolant flows inside the plurality of spaces 46
from the introduction pipe 32 side toward the discharge pipe 34
side. Here, the flow of the circulating coolant flowing through the
heat exchanger 30 will be described with reference to FIG. 3A. The
circulating coolant cooled by the external heat exchanger 52 (refer
to FIG. 1A) is introduced into the introduction pipes 32 from the
introduction port 38. The circulating coolant introduced into the
introduction pipes 32 flows inside the introduction pipes 32 from
the upper side to the lower side in the direction of gravity, and
sequentially flows into the plurality of connecting pipes 36 in the
process. The circulating coolant that has flowed into the
connecting pipes 36 flows inside the spaces 46 formed in the
connecting pipes 36 from the introduction pipe 32 side toward the
discharge pipe 34 side and then flows into the discharge pipes 34.
The circulating coolant that has flowed into the discharge pipes
34, flows inside the discharge pipes 34 from the lower side to the
upper side in the direction of gravity, and then is discharged from
the discharge port 42 toward the external heat exchanger 52.
[0025] In this way, the circulating coolant flows through the heat
exchanger 30 and is not mixed with the coolant 14 stored in the
main tank body 10. For example, it is conceivable that the coolant
14 stored in the main tank body 10 is circulated by a pump to an
external heat exchanger provided outside the main tank body 10 to
cool the coolant 14. In this case, when the wiring board 70 is put
in and taken out from the main tank body 10, foreign matter may
become mixed in the coolant 14, and the pump circulating the
coolant 14 may fail. On the other hand, in the first embodiment,
since the circulating coolant flowing through the heat exchanger 30
and the coolant 14 stored in the main tank body 10 are not mixed,
even in a case where foreign matter is mixed in the coolant 14,
failure of the pump 54 for circulating the circulating coolant may
be suppressed.
[0026] Here, in explaining the effect of the immersion tank 100 of
the first embodiment, an immersion tank of a comparative example
will be described. FIG. 4 is a see-through front view of an
immersion tank according to the comparative example. As illustrated
in FIG. 4, in the immersion tank 500 of the comparative example,
the heat exchanger 80 is immersed in the coolant 14 and
accommodated in the main tank body 10. The heat exchanger 80 has an
introduction pipe 82, a discharge pipe 84, and a flat plate member
86 in which a flow path is formed. A heat sink 88 having radiating
fins may be provided on the main surface of the flat plate member
86. The flat plate member 86 is provided at a bottom portion
positioned on the lower side in the direction of gravity of the
main tank body 10. The wiring board 70 on which the electronic
components 60, 62, and 64 are mounted is arranged on the upper side
in the direction of gravity of the flat plate member 86. The
introduction pipe 82 and the discharge pipe 84 are connected to an
external heat exchanger 52 such as a chiller or the like via the
pipe 50.
[0027] When the pump 54 is driven, the circulating coolant that is
cooled by the external heat exchanger 52 is introduced into the
introduction pipe 82. The circulating coolant introduced into the
introduction pipe 82 flows through a flow path formed inside the
flat plate member 86 and then is discharged from the discharge pipe
84 toward the external heat exchanger 52.
[0028] According to the comparative example, in order to cool the
coolant 14 stored in the main tank body 10, the heat exchanger 80
is immersed in the coolant 14. The flat plate member 86 of the heat
exchanger 80 is installed at a bottom portion of the main tank body
10, so the coolant 14 in the vicinity of the bottom portion of the
main tank body 10 is cooled. However, the coolant 14 that is warmed
by the electronic components 60, 62, and 64 tends to rise upward in
the direction of gravity more than the electronic components 60,
62, and 64, while on the other hand, the coolant 14 that is cooled
by the flat plate member 86 of the heat exchanger 80 tends to
accumulate in the vicinity of the bottom portion positioned on the
lower side in the direction of gravity of the main tank body 10.
Therefore, the temperature difference between the circulating
coolant flowing through the flat plate member 86 and the coolant 14
existing around the flat plate member 86 is small, and effective
heat exchange is difficult to perform. In addition, it is difficult
for convection to occur in the coolant 14. As a result, it is
difficult to perform effective cooling of the electronic components
60, 62, and 64.
[0029] FIG. 5 is a cross-sectional view for explaining the effect
of the immersion tank according to the first embodiment. As
described using FIG. 1A and FIG. 1B, in the first embodiment, the
heat exchanger 30 immersed in the coolant 14 has introduction pipes
32 and discharge pipes 34 extending in the direction of gravity and
a plurality of connecting pipes 36 connected between the
introduction pipes 32 and the discharge pipes 34. The plurality of
connecting pipes 36 is arranged side by side in a plurality of rows
in a second intersecting direction that intersects the direction of
gravity and are arranged side by side in a plurality of stages in
the direction of gravity. In this case, as illustrated in FIG. 5,
the density of the coolant 14 that is warmed by the electronic
component 60 is lower than that of the surrounding coolant 14, and
as indicated by an arrow 90, rises toward the upward side in the
direction of gravity. On the other hand, the coolant 14 that is
cooled by the circulating coolant flowing in the connecting pipes
36 has a density higher than that of the surrounding coolant 14,
and as indicated by an arrow 92, descends toward the lower side in
the direction of gravity. At this time, the coolant 14 located
between the connecting pipes 36 arranged side by side in a
plurality of rows tends to be cooled by the circulating coolant
flowing inside the connecting pipes 36, and because it is difficult
for that coolant 14 to be affected by the coolant 14 existing
outside the connecting pipes 36 arranged side by side in a
plurality of rows, it is not easily warmed up. Therefore, a flow of
coolant 14 descending toward the lower side in the direction of
gravity as indicated by the arrow 92 tends to occur between the
connecting pipes 36 arranged side by side in a plurality of
rows.
[0030] Even when the connecting pipes 36 are arranged side by side
in a plurality of stages in the direction of gravity, a flow of the
coolant 14 descending toward the lower side in the direction of
gravity as indicated by the arrow 92 tends to occur between the
connecting pipes 36 arranged side by side in a plurality of rows.
This is due to the following reason. For example, in a case where
one large connecting pipe 36 extends in the direction of gravity
from the upper end side to the lower end side of the introduction
pipes 32 and the discharge pipes 34, the flow path resistance
between the connecting pipes 36 arranged side by side in a
plurality of rows becomes large. In this case, it becomes difficult
for the coolant 14 to flow toward the lower side in the direction
of gravity between the connecting pipes 36 arranged side by side in
a plurality of rows. On the other hand, by providing connecting
pipes 36 arranged side by side in a plurality of stages in the
direction of gravity, the flow path resistance between the
connecting pipes 36 arranged side by side in a plurality of rows
becomes small. For this reason, a flow of the coolant 14 descending
toward the lower side in the direction of gravity such as indicated
by the arrow 92 tends to occur between the connecting pipes 36
arranged side by side in a plurality of rows.
[0031] By generating an upward flow and a downward flow in the
coolant 14 stored in the main tank body 10 in this way, a flow in
which the coolant 14 circulates inside the main tank body 10 is
produced as indicated by arrows 90 to 96. As a result, the
temperature difference of the coolant 14 stored in the main tank
body 10 becomes small. Therefore, heat exchange between the
circulating coolant flowing through the heat exchanger 30 and the
coolant 14 stored in the main tank body 10 is effectively
performed, and the electronic component 60 is effectively
cooled.
[0032] According to the first embodiment, as illustrated in FIG.
1A, the heat exchanger 30 immersed in the coolant 14 includes
introduction pipes 32 into which the circulating coolant is
introduced, discharge pipes 34 for discharging the circulating
coolant, and a plurality of connecting pipes 36 that connects
between the introduction pipes 32 and the discharge pipes 34 and
through which the circulating coolant flows from the introduction
pipes 32 toward the discharge pipes 34. As illustrated in FIG. 3A
and FIG. 3B, the plurality of connecting pipes 36 is arranged side
by side in a plurality of rows in a second intersecting direction
intersecting the direction of gravity and arranged side by side in
a plurality of stages in the direction of gravity. By arranging the
connecting pipes 36 side by side in a plurality of rows in the
second intersecting direction intersecting the direction of gravity
and side by side in a plurality of stages in the direction of
gravity in this way, as described with reference to FIG. 5, a
downward flow may be effectively generated in the coolant 14 stored
in the main tank body 10. Therefore, convection may be effectively
generated in the coolant 14 stored in the main tank body 10,
coupled with an upward flow by the coolant 14 that is warmed by the
electronic component 60 or the like, so the cooling performance may
be improved.
[0033] As the number of rows of connecting pipes 36 arranged side
by side in a plurality of rows in the second intersecting direction
intersecting the direction of gravity increases, it becomes
difficult for the coolant 14 existing between the connecting pipes
36 located inside the rows to be influenced by the coolant 14
existing further outside than the connecting pipes 36 arranged side
by side in the plurality of rows. For example, as the number of
rows of the connecting pipes 36 arranged side by side in a
plurality of rows increases, it becomes easy for the coolant 14
existing between the connecting pipes 36 located inside the rows to
be cooled. Therefore, a large downward flow tends to occur, and a
large convection tends to occur in the coolant 14. For this reason,
the number of rows of the connecting pipes 36 arranged side by side
in a plurality of rows in the second intersecting direction is
preferably three rows or more, and more preferably five rows or
more, and even more preferably eight rows or more. From the aspect
of suppressing the enlargement of the main tank body 10, the number
of rows of the connecting pipes 36 arranged side by side in a
plurality of rows in the second intersecting direction is
preferably ten rows or less, and more preferably seven rows or
less, and even more preferably four rows or less.
[0034] As illustrated in FIG. 3A and FIG. 3B, the plurality of
connecting pipes 36 has a cross-sectional shape having a
longitudinal direction and a lateral direction. The direction of
gravity is taken to be the longitudinal direction and the second
intersecting direction intersecting the direction of gravity is
taken to be the lateral direction, and preferably the plurality of
connecting pipes 36 is arranged side by side in a plurality of rows
in the second intersecting direction and arranged side by side in a
plurality of stages in the direction of gravity. As a result, the
area where the connecting pipes 36 and the coolant 14 contact,
among the connecting pipes 36 arranged side by side in a plurality
of rows may be increased as compared with a case where the
cross-sectional shape of the connecting pipes 36 is a circular
shape, for example. Therefore, the coolant 14 may be effectively
cooled by the circulating coolant flowing in the connecting pipes
36, and a downward flow may be effectively generated. Even in a
case where the connecting pipes 36 are arranged side by side in a
plurality of rows, the installation space may be reduced. Note that
even when the cross-sectional shape of the connecting pipes 36 is a
circular shape, the effect of improving the cooling performance by
generating convection in the coolant 14 is obtained.
[0035] As illustrated in FIG. 3B, the interior of the connecting
pipes 36 is preferably partitioned into a plurality of spaces 46.
As a result, the circulating coolant flowing in the connecting
pipes 36 may be suppressed from being biased toward a part inside
the connecting pipes 36, and wall portions partitioning the
interior of the connecting pipes 36 into a plurality of spaces 46
also contribute to cooling of the coolant 14 by the circulating
coolant. Therefore, the cooling effect of the coolant 14 stored in
the main tank body 10 may be improved. By partitioning the interior
of the connecting pipes 36 into a plurality of spaces 46, the
strength of the connecting pipes 36 may be improved as compared
with a case where the connecting pipes 36 are not partitioned into
a plurality of spaces but is a single space.
[0036] As illustrated in FIG. 1A and FIG. 1B, the case of arranging
the plurality of connecting pipes 36 so as to be shifted in a
direction intersecting the direction of gravity with respect to the
wiring board 70 on which the electronic component 60 and the like
are mounted is preferable. As a result, a circulating flow of the
coolant 14 stored in the main tank body 10 may be effectively
generated as described with reference to FIG. 5. In FIG. 1A and
FIG. 1B, the wiring board 70 is arranged near the center of the
connecting pipes 36 arranged side by side in a plurality of stages
in the direction of gravity, but may also be biased toward the
upper side or the lower side. In FIG. 1A and FIG. 1B, the plurality
of connecting pipes 36 is arranged so as to be shifted in the
second intersecting direction with respect to the wiring board 70,
however, even in a case of being arranged so as to be shifted in
the first intersecting direction, a flow in which the coolant 14
stored in the main tank body 10 circulates may be effectively
generated. As illustrated in FIG. 1A and FIG. 1B, from the aspect
of effectively creating a circulating flow of the coolant 14 stored
in the main tank body 10, preferably the wiring board 70 is
accommodated in the main tank body 10 so as to stand upright in the
direction of gravity.
[0037] The coolant 14 stored in the main tank body 10 and the
circulating coolant flowing through the heat exchanger 30 may be
the same type of coolant or may be different kinds of coolant. Even
in a case where the circulating coolant flowing through the heat
exchanger 30 flows out to the main tank body 10 for some reason, by
making the coolant 14 stored in the main tank body 10 and the
circulating coolant flowing through the heat exchanger 30 be the
same type of coolant, the adverse effects on the electronic
component 60 and the like may be suppressed. In addition, by making
the coolant 14 stored in the main tank body 10 and the circulating
coolant flowing through the heat exchanger 30 be different types of
coolant, a coolant having a high heat dissipating capacity suitable
for cooling may be adopted as the circulating coolant. For example,
the coolant 14 stored in the main tank body 10 may be a
fluorine-based insulating coolant and the circulating coolant
flowing through the heat exchanger 30 may be water or a propylene
glycol-based coolant.
[0038] In the first embodiment, a case in which the introduction
pipes 32 and the discharge pipes 34 extend in the direction of
gravity was described as an example, however the technique is not
limited to this case and these pipes may extend in a direction
inclined from the direction of gravity.
Second Embodiment
[0039] FIG. 6A is a see-through front view of an immersion tank
according to a second embodiment, and FIG. 6B is a cross-sectional
view taken along a line VIB-VIB of FIG. 6A. In the case of the
immersion tank 100 of the first embodiment, as illustrated in FIG.
1A and FIG. 1B, an example is described in which the wiring board
70 on which the electronic component 60 and the like are mounted is
arranged on only one side with respect to the heat exchanger 30.
However, as in the case of the immersion tank 200 of the second
embodiment, the wiring board 70 on which the electronic component
60 and the like are mounted may be arranged on one side of the heat
exchanger 30, and a wiring board 74 on which an electronic
component 66 and the like are mounted may be arranged on the other
side. In this case, the upward flow of the coolant 14 that is
warmed by the electronic components 60 and 66 is increased, so
convection of the coolant 14 stored in the main tank body 10 may be
effectively generated.
[0040] Although embodiments have been described in detail above,
the embodiments are not limited to the specific embodiments, and
various modifications and changes may be made within the range of
the gist of the embodiments described in the claims.
[0041] All examples and conditional language provided herein are
intended for the pedagogical purposes of aiding the reader in
understanding the invention and the concepts contributed by the
inventor to further the art, and are not to be construed as
limitations to such specifically recited examples and conditions,
nor does the organization of such examples in the specification
relate to a showing of the superiority and inferiority of the
invention. Although one or more embodiments of the present
invention have been described in detail, it should be understood
that the various changes, substitutions, and alterations could be
made hereto without departing from the spirit and scope of the
invention.
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