U.S. patent application number 14/110671 was filed with the patent office on 2014-01-30 for piping structure of cooling device, method for making the same, and method for connecting pipes.
This patent application is currently assigned to NEC CORPORATION. The applicant listed for this patent is Masaki Chiba, Kenichi Inaba, Arihiro Matsunaga, Hitoshi Sakamoto, Minoru Yoshikawa. Invention is credited to Masaki Chiba, Kenichi Inaba, Arihiro Matsunaga, Hitoshi Sakamoto, Minoru Yoshikawa.
Application Number | 20140027100 14/110671 |
Document ID | / |
Family ID | 47009478 |
Filed Date | 2014-01-30 |
United States Patent
Application |
20140027100 |
Kind Code |
A1 |
Yoshikawa; Minoru ; et
al. |
January 30, 2014 |
PIPING STRUCTURE OF COOLING DEVICE, METHOD FOR MAKING THE SAME, AND
METHOD FOR CONNECTING PIPES
Abstract
In a piping structure of a cooling device using an ebullient
cooling system, the cooling performance of the cooling device is
degraded if the pipe is provided with flexibility, therefore, a
piping structure of a cooling device according to an exemplary
aspect of the invention includes a first tubular part with a hollow
portion through which a refrigerant used in the cooling device
flows; wherein the first tubular part is made of metal materials;
and the surface roughness of the inner surface of the first tubular
part is less than or equal to the size of a condensation nucleus
for the refrigerant.
Inventors: |
Yoshikawa; Minoru; (Tokyo,
JP) ; Sakamoto; Hitoshi; (Tokyo, JP) ; Chiba;
Masaki; (Tokyo, JP) ; Inaba; Kenichi; (Tokyo,
JP) ; Matsunaga; Arihiro; (Tokyo, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Yoshikawa; Minoru
Sakamoto; Hitoshi
Chiba; Masaki
Inaba; Kenichi
Matsunaga; Arihiro |
Tokyo
Tokyo
Tokyo
Tokyo
Tokyo |
|
JP
JP
JP
JP
JP |
|
|
Assignee: |
NEC CORPORATION
Tokyo
JP
|
Family ID: |
47009478 |
Appl. No.: |
14/110671 |
Filed: |
April 10, 2012 |
PCT Filed: |
April 10, 2012 |
PCT NO: |
PCT/JP2012/060197 |
371 Date: |
October 8, 2013 |
Current U.S.
Class: |
165/177 |
Current CPC
Class: |
F28F 1/003 20130101;
F28F 21/084 20130101; F28F 19/04 20130101; F28F 13/187 20130101;
F28F 1/00 20130101; F28D 15/0266 20130101; F28F 2255/02
20130101 |
Class at
Publication: |
165/177 |
International
Class: |
F28F 1/00 20060101
F28F001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 2011 |
JP |
2011-089347 |
Claims
1. A piping structure of cooling device, comprising: a first
tubular part with a hollow portion through which a refrigerant used
in the cooling device flows; wherein the first tubular part is made
of metal materials; and the surface roughness of the inner surface
of the first tubular part is less than or equal to the size of a
condensation nucleus for the refrigerant.
2. The piping structure of cooling device according to claim 1,
wherein the first tubular part is formed through an annealing
process.
3. The piping structure of cooling device according to claim 1,
wherein the surface roughness of an inner surface of the first
tubular part is equal to or more than 0.1 micrometers and less than
or equal to 10 micrometers.
4. The piping structure of cooling device according to claim 1,
wherein the thickness of the first tubular part is equal to or more
than 0.4 mm and less than or equal to 1 mm.
5. The piping structure of cooling device according to claim 1,
comprising: the first tubular part; and a second tubular part with
which the first tubular part is covered, wherein the second tubular
part is made of organic materials.
6. The piping structure of cooling device according to claim 1,
further comprising: a first connection connected to an evaporator
storing a refrigerant; and a second connection connected to a
condenser condensing and liquefying a vapor-state refrigerant
vaporized in the evaporator and radiating heat.
7. A cooling device, comprising: an evaporator storing a
refrigerant; a condenser condensing and liquefying a vapor-state
refrigerant vaporized in the evaporator and radiating heat; and a
pipe connecting the evaporator to the condenser, wherein the pipe
comprises the a piping structure of cooling device, the piping
structure of cooling device, comprising a first tubular part with a
hollow portion through which a refrigerant used in the cooling
device flows; wherein the first tubular part is made of metal
materials; and the surface roughness of the inner surface of the
first tubular part is less than or equal to the size of a
condensation nucleus for the refrigerant.
8. The cooling device according to claim 7, wherein the evaporator
comprises a first connective projection connected to the pipe; the
condenser comprises a second connective projection connected to the
pipe; and at least one of the first connective projection and the
second connective projection is made of the same material as a
metal material of which the first tubular part is made.
9. A method for making a piping structure of cooling device,
comprising the steps of: applying a rolling process to a metal
material composing a hollow portion through which a refrigerant
used in a cooling device flows; forming a plate-like metal plate
material with a surface roughness less than or equal to the size of
a condensation nucleus for the refrigerant by the rolling process;
and bending the metal plate material into a tube and joining both
ends.
10. The method for making a piping structure of cooling device
according to claim 9, further comprising: performing an annealing
process subsequently to the joining process.
11. The method for making a piping structure of cooling device
according to claim 9, further comprising: forming a first tubular
part made of metal materials by the joining process; and covering
the outer periphery of the first tubular part by ejecting an
organic material and forming a second tubular part made of the
organic material.
12. A method for connecting pipes, comprising the steps of:
fitting, in a connective projection, a pipe comprising a first
tubular part, the first tubular part having a hollow portion
through which a refrigerant used in a cooling device flowing, made
of a metal material, and a surface roughness of its inner surface
being less than or equal to the size of a condensation nucleus for
the refrigerant; applying a pressure from the outer periphery of
the pipe toward the center; and deforming the metal material
composing the first tubular part by the pressure and attaching
firmly the metal material to the connective projection.
13. The method for connecting pipes according to claim 12, wherein
the first tubular part is formed through an annealing process.
14. The method for connecting pipes according to claim 12, wherein
the pipe comprises a second tubular part, which is made of organic
materials, with which the first tubular part is covered; and the
pressure is applied from the outer periphery of the second tubular
part toward the center.
Description
TECHNICAL FIELD
[0001] The present invention relates to piping structures of
cooling devices for semiconductor devices and electronic devices
and the like, in particular, to a piping structure of a cooling
device using an ebullient cooling system in which the heat
transportation and heat radiation are performed by a cycle of
vaporization and condensation of a refrigerant, a method for making
the same, and a method for connecting pipes.
BACKGROUND ART
[0002] In recent years, with the progress of high performance and
high functionality in semiconductor devices and electronic devices,
the amount of heat generation from them has been increasing. On the
other hand, the miniaturization of semiconductor devices and
electronic devices has been advancing due to the popularization of
portable devices. Because of such background, a cooling device with
high efficiency and a small size is highly required. The cooling
device using an ebullient cooling system in which the heat
transportation and heat radiation are performed by a cycle of
vaporization and condensation of a refrigerant, is expected as a
cooling device for the semiconductor devices and the electronic
devices because it does not require any driving unit such as a
pump.
[0003] An example of the cooling device using an ebullient cooling
system (hereinafter, also referred to as an ebullient cooling
device) is described in patent literature 1. The ebullient cooling
device described in patent literature 1 includes an evaporator
absorbing the heat from a heating element by the evaporation action
of working fluids such as pure water and ethanol, and a condenser
releasing heat by the condensation action of working fluids. The
ebullient cooling device includes flow conduits circulating the
working fluids between the evaporator and the condenser, and is
configured so that the flow conduits can be bent at a number of
points. It is said that the configuration enables the flow conduits
to act as a spring and to absorb the force applied to the
evaporator and the condenser.
[0004] In the ebullient cooling device described in patent
literature 1, however, a metal pipe made of rigid metal with a
spring function is used as the flow conduit, and consequently,
there has been a problem that the degree of freedom to dispose the
flow conduits with a bent form is limited. There has also been a
problem that the mechanical strength cannot be maintained, for
example, a buckling occurs in the process of bending, if the
thickness of the metal pipe is reduced to a thickness in which it
can be bent freely. Furthermore, there has been a problem that the
corrosion (electrical corrosion) based on an electrochemical action
occurs due to the electrical potential difference between the metal
composing the flow conduit and the metal composing a connection of
the evaporator or the condenser if an electrically-conductive
refrigerant is used.
[0005] On the other hand, a low-boiling organic refrigerant is
often used as the refrigerant in the ebullient cooling device in
order to improve the cooling performance within a range of the
operation temperature for a semiconductor device and an electronic
device. It is possible to obtain a flexible pipe by using an
organic material such as resin and rubber. If a pipe made of an
organic material is used, however, there has been a problem that
the internal pressure increases due to a chemical reaction with the
organic refrigerant, and consequently, the cooling performance is
degraded owing to the boiling point elevation of the
refrigerant.
[0006] Patent literature 2 describes a technology to solve such
problems. An ebullient cooling device described in patent
literature 2 includes an evaporator container accommodating a
refrigerant liquid, a condenser condensing the vaporized
refrigerant, and a single pipe connecting the evaporator container
to the condenser, through which a gas-liquid flows in a mixed
phase. The pipe has a structure in which a thin film of a
corrosion-resistant and permeation-resistant material such as
aluminum and stainless steel is evaporated onto the inner wall of
the pipe made of a resin. It is said that the structure enables the
pipe to have enough rigidity to maintain its shape against the
atmospheric pressure and thus the installation location of the
evaporator container and the condenser can be freely decided.
[0007] Patent literature 1: Japanese Patent Application Laid-Open
Publication No. 2006-125718 (paragraphs [0025] to [0044])
[0008] Patent literature 2: Japanese Patent Application Laid-Open
Publication No. 1994-224337 (paragraphs [004] to [009])
DISCLOSURE OF INVENTION
Problem to be Solved by the Invention
[0009] As mentioned above, the pipe in the related ebullient
cooling device has a structure in which a metal film is evaporated
onto the inner surface of the pipe. The vapor of the refrigerant,
however, is condensed again and liquefies in the middle of the pipe
due to the surface roughness of the metal film evaporated on the
resin. The related ebullient cooling device using such pipes,
therefore, has a problem that the amount of heat transports by the
refrigerant decreases.
[0010] Thus, in the piping structure of the related ebullient
cooling device, there is a problem that the cooling performance of
the cooling device is degraded if the pipe is provided with
flexibility.
[0011] The objective of the present invention is to provide a
piping structure of a cooling device, a method for making the same,
and a method for connecting pipes which solve the problem mentioned
above that in a piping structure of a cooling device using an
ebullient cooling system, the cooling performance of the cooling
device is degraded if the pipe is provided with flexibility.
Means for Solving a Problem
[0012] A piping structure of a cooling device according to an
exemplary aspect of the invention includes a first tubular part
with a hollow portion through which a refrigerant used in the
cooling device flows; wherein the first tubular part is made of
metal materials; and the surface roughness of the inner surface of
the first tubular part is less than or equal to the size of a
condensation nucleus for the refrigerant.
[0013] A method for making a piping structure of cooling device
according to an exemplary aspect of the invention includes the
steps of: applying a rolling process to a metal material composing
a hollow portion through which a refrigerant used in a cooling
device flows; forming a plate-like metal plate material with a
surface roughness less than or equal to the size of a condensation
nucleus for the refrigerant by the rolling process; and bending the
metal plate material into a tube and joining both ends.
[0014] A method for connecting pipes according to an exemplary
aspect of the invention includes the steps of: fitting, in a
connective projection, a pipe including a first tubular part, the
first tubular part having a hollow portion through which a
refrigerant used in a cooling device flowing, made of a metal
material, and a surface roughness of its inner surface being less
than or equal to the size of a condensation nucleus for the
refrigerant; applying a pressure from the outer periphery of the
pipe toward the center; and deforming the metal material composing
the first tubular part by the pressure and attaching firmly the
metal material to the connective projection.
Effect of the Invention
[0015] According to the piping structure of the cooling device of
the present invention, it is possible to obtain a piping structure
of a cooling device which does not cause deterioration in the
cooling performance of the cooling device even if the pipe is
provided with flexibility.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1A is a plan view showing a configuration of a piping
structure of a cooling device in accordance with the first
exemplary embodiment of the present invention,
[0017] FIG. 1B is a cross-sectional view showing a configuration of
a piping structure of a cooling device in accordance with the first
exemplary embodiment of the present invention.
[0018] FIG. 2A is a plan view showing a configuration of a piping
structure of a cooling device in accordance with the second
exemplary embodiment of the present invention.
[0019] FIG. 2B is a cross-sectional view showing a configuration of
a piping structure of a cooling device in accordance with the
second exemplary embodiment of the present invention.
[0020] FIG. 3A is a cross-sectional view to illustrate a method for
making the piping structure of cooling device in accordance with
the second exemplary embodiment of the present invention.
[0021] FIG. 3B is a cross-sectional view to illustrate a method for
making the piping structure of cooling device in accordance with
the second exemplary embodiment of the present invention.
[0022] FIG. 4 is a cross-sectional view showing a configuration of
an ebullient cooling device in accordance with the third exemplary
embodiment of the present invention.
[0023] FIG. 5A is a cross-sectional view to illustrate a method for
connecting pipes in the cooling device in accordance with the third
exemplary embodiment of the present invention.
[0024] FIG. 5B is a cross-sectional view to illustrate a method for
connecting pipes in the cooling device in accordance with the third
exemplary embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0025] The exemplary embodiments of the present invention will be
described with reference to drawings below.
The First Exemplary Embodiment
[0026] FIGS. 1A and 1B show configurations of a piping structure of
cooling device 10 in accordance with the first exemplary embodiment
of the present invention. FIG. 1A is a plan view and FIG. 1B is a
cross-sectional view in a plane perpendicular to the axial
direction of the piping structure (a cross-sectional view taken
along the line A-A of FIG. 1A). The piping structure of cooling
device 10 in accordance with the present exemplary embodiment
includes a first tubular part 11 with a hollow portion through
which a refrigerant used in the cooling device flows.
[0027] The first tubular part 11 is made of metal materials, and
the surface roughness of the inner surface of the first tubular
part 11 is less than or equal to the size of a condensation nucleus
for the refrigerant. Here, the condensation nucleus means a spot
which acts as a base point when a vapor liquefies. If the vapor
touches the base points, the liquefaction is accelerated there. It
is possible to use aluminum materials and the like as the first
tubular part 11, for example. By setting the center line average
roughness of a surface equal to or more than 0.1 micrometers and
less than or equal to 10 micrometers, preferably less than or equal
to 1 micrometer, it is possible to prevent the inner surface of the
first tubular part 11 from acting as a condensation nucleus of the
refrigerant.
[0028] It is possible to use a material formed through an annealing
process for the first tubular part. By means of the annealing
process, it is possible to adjust a strain arising at a processing
treatment, and it becomes possible to maintain the strength of the
first tubular part with maintenance of its flexibility.
[0029] Next, the method for making the piping structure of cooling
device 10 according to the present exemplary embodiment will be
described. In the method for making according to the present
exemplary embodiment, first, a plate-like metal plate material made
of a metal material such as aluminum is prepared. The metal plate
material can be produced by a conventional rolling process. The
metal plate material is bent into a tube by using a cylindrical jig
such as a roll, for example, and both ends are joined by means of a
weld process and the like. By this process, the first tubular part
11 made of a metal material is completed. It is also acceptable to
perform the annealing process subsequently. The annealing process
can be performed under conditions normally used for the metal
material to be used. It is desirable to set the thickness of the
first tubular part, which is determined by the plate thickness of
the metal plate material, equal to or more than 0.4 mm and less
than or equal to 1 mm. This is because it becomes difficult to weld
the ends and to maintain the bending strength and the internal
pressure capacity of the first tubular part if the plate thickness
of the metal plate material becomes thinner than 0.4 mm. On the
other hand, it is also because the flexibility of the piping
structure of cooling device 10 decreases if the thickness of the
first tubular part is more than 1 mm.
[0030] As mentioned above, according to the present exemplary
embodiment, it is possible to obtain a piping structure of a
cooling device which does not cause deterioration in the cooling
performance of the cooling device even if the pipe is provided with
flexibility.
The Second Exemplary Embodiment
[0031] Next, the second exemplary embodiment of the present
invention will be described. FIGS. 2A and 2B show configurations of
a piping structure of cooling device 100 according to the second
exemplary embodiment of the present invention. FIG. 2A is a plan
view and FIG. 2B is a cross-sectional view in a plane perpendicular
to the axial direction of the piping structure (a cross-sectional
view taken along the line A-A of FIG. 2A). The piping structure of
cooling device 100 in accordance with the present exemplary
embodiment includes a first tubular part 110 with a hollow portion
through which a refrigerant used in the cooling device flows, and a
second tubular part 120 with which the first tubular part 110 is
covered.
[0032] The first tubular part 110 is made of metal materials, and
the surface roughness of the inner surface of the first tubular
part 110 is less than or equal to the size of a condensation
nucleus for the refrigerant. Here, the condensation nucleus means a
spot which acts as a base point when a vapor liquefies. If the
vapor touches the base points, the liquefaction is accelerated
there. It is possible to use aluminum materials and the like as the
first tubular part 110, for example. By setting the center line
average roughness of a surface equal to or more than 0.1
micrometers and less than or equal to 10 micrometers, preferably
less than or equal to 1 micrometer, it is possible to prevent the
inner surface of the first tubular part 110 from acting as a
condensation nucleus of the refrigerant.
[0033] The second tubular part is made of organic materials such as
resin and rubber, and it is possible to use polyethylene materials
and butyl rubber materials, for example.
[0034] As mentioned above, the piping structure of cooling device
100 according to the present exemplary embodiment is configured in
which the first tubular part 110 touching the refrigerant is made
of metal materials and the surface roughness of the inner surface
is less than or equal to the size of a condensation nucleus for the
refrigerant. Accordingly, it is possible to prevent the piping
structure of cooling device 100 from reacting chemically with the
refrigerant, and prevent the vapor of the refrigerant from
condensing again. Additionally, since the piping structure of
cooling device 100 includes a multi-layered structure in which the
first tubular part 110 is covered with the second tubular part 120
made of organic materials, it is possible to maintain the
mechanical strength of the piping structure of cooling device 100
with maintenance of its flexibility. As a result, according to the
present exemplary embodiment, it is possible to obtain a piping
structure of a cooling device which does not cause deterioration in
the cooling performance of the cooling device even if the pipe is
provided with flexibility.
[0035] Next, the method for making the piping structure of cooling
device 100 according to the present exemplary embodiment will be
described. FIGS. 3A and 3B are cross-sectional views to illustrate
a method for making the piping structure of cooling device 100
according to the present exemplary embodiment. In the method for
making according to the present exemplary embodiment, first, a
plate-like metal plate material 140 made of a metal material such
as aluminum is prepared. As shown in FIG. 3A, the metal plate
material 140 is bent into a tube by using a cylindrical jig 150
such as a roll, for example, and both ends 160 are joined by means
of a weld process and the like. By this process, the first tubular
part 110 made of a metal material is formed.
[0036] Subsequently, as shown in FIG. 3B, the outer periphery of
the first tubular part 110 is covered by ejecting a resin material
such as polyethylene from a nozzle 170 and the like, for example.
By this process, the second tubular part made of the organic
material is formed with which the first tubular part 110 is
covered, and the piping structure of cooling device 100 is
completed. Since the method for making the piping structure of
cooling device 100 according to the present exemplary embodiment is
composed of the simple processes, it is possible to manufacture the
piping structure of cooling device 100 massively and cheaply
according to the present method for making.
[0037] Here, it is desirable to set the surface roughness of the
inner surface of the first tubular part 110 made of the metal plate
material 140 equal to or more than 0.1 micrometers and less than or
equal to 10 micrometers, preferably less than or equal to 1
micrometer. This can be achieved by producing the metal plate
material 140 by means of a conventional rolling process. By setting
the surface roughness within the range, it is possible to prevent
the inner surface of the first tubular part 110 from acting as a
condensation nucleus of the refrigerant. It is desirable to set the
thickness of the first tubular part, which is determined by the
plate thickness of the metal plate material 140, equal to or more
than 0.4 mm and less than or equal to 1 mm. This is because it
becomes difficult to weld the ends 160 and to maintain the bending
strength and the internal pressure capacity of the first tubular
part if the plate thickness of the metal plate material 140 becomes
thinner than 0.4 mm. On the other hand, it is also because the
flexibility of the piping structure of cooling device 100 decreases
if the thickness of the first tubular part is more than 1 mm.
The Third Exemplary Embodiment
[0038] Next, the third exemplary embodiment of the present
invention will be described. In the present exemplary embodiment, a
cooling device will be described which uses the piping structure of
cooling device 100 according to the second exemplary embodiment,
but it is also acceptable to use the piping structure of cooling
device 10 according to the first exemplary embodiment. A case will
be described below in which the piping structure is applied to a
cooling device using an ebullient cooling system (hereinafter,
referred to as an ebullient cooling device). FIG. 4 is a
cross-sectional view showing a configuration of an ebullient
cooling device 200 in accordance with the present exemplary
embodiment. The ebullient cooling device 200 includes an evaporator
220 storing a refrigerant 210, and a condenser 230 condensing and
liquefying a vapor-state refrigerant vaporized in the evaporator
220 and radiating heat. A heat-generating part 240 of an object to
be cooled such as a semiconductor device is disposed so as to
thermally contact with one surface of the evaporator 220.
[0039] The evaporator 220 is connected to the condenser 230 by
using the piping structure of cooling device 100 according to the
second exemplary embodiment. As shown in FIG. 2A, the piping
structure of cooling device 100 includes a first connection 131
connected to the evaporator 210 and a second connection 132
connected to the condenser 230. FIG. 4 shows a case where the
piping structure of cooling device 100 is used for a vapor-phase
pipe 251 through which a vapor-phase refrigerant flows from the
evaporator 220 toward the condenser 230 and for a liquid-phase pipe
252 through which a liquid-phase refrigerant flows from the
condenser 230 toward the evaporator 220. The bending strength of
the vapor-phase pipe 251 and the liquid-phase pipe 252 (hereafter,
referred to as "a pipe 250" simply) is maintained by means of the
second tubular part 120 made of organic materials having the
flexibility. In the ebullient cooling device 200, therefore, it is
possible to decide freely the disposition of the evaporator 220 and
the condenser 230 with maintenance of the mechanical strength of
the pipe connecting the evaporator 220 to the condenser 230.
[0040] As mentioned above, the ebullient cooling device 200 of the
present exemplary embodiment is configured in which the evaporator
220 is connected to the condenser 230 by using the pipe 250
including the first tubular part 110 made of metal materials as the
inner layer and the second tubular part 120 made of organic
materials having the flexibility as the outer layer. By adopting
this configuration, it is possible to change the layout of the
ebullient cooling device 200 easily even if the layout or the
specifications of a device to be cooled are changed. Accordingly,
it becomes unnecessary to design and produce the evaporator 220 and
the condenser 230 with respect to each device to be cooled, and it
becomes possible to standardize them. As a result, it is possible
to reduce the costs of the evaporator 220 and the condenser
230.
[0041] It is also possible that the evaporator 220 is configured to
include a first connective projection 221 connected to the first
connection 131 of the piping structure of cooling device 100 and
the condenser 230 is configured to include a second connective
projection 231 connected to the second connection 132. It is also
acceptable that at least one of the first connective projection 221
and the second connective projection 231 is made of the same
material as the metal material of which the first tubular part 131
is made. In this case, since the electrical potential difference
does not arise between the same type of metals, it is possible to
prevent the corrosion based on the electrochemical action
(electrical corrosion) even though a conductive refrigerant such as
water is used.
[0042] In general, a semiconductor device, an electronic device and
the like are designed so as to operate at temperature in the range
from several tens of degrees Celsius to about 100 degrees Celsius.
By using a material with small surface tension and a low boiling
point as the refrigerant used in the ebullient cooling device,
therefore, it is possible to activate the generation of bubbles in
the evaporator and improve the cooling performance. For this
reason, organic refrigerants such as hydrofluorocarbon and
hydrofluoroether are used as the refrigerant. These organic
refrigerants, however, react chemically with organic materials such
as resin and rubber. Since the chemical reaction generates a
reaction gas and the internal pressure in the related ebullient
cooling device increases, the boiling point of the refrigerant
rises. As a result, the cooling performance in the related
ebullient cooling device is degraded by the prolonged use.
[0043] In contrast, the ebullient cooling device 200 of the present
exemplary embodiment uses the piping structure of cooling device
100 including the first tubular part 110 made of metal materials as
the vapor-phase pipe 251 and the liquid-phase pipe 252. As a
result, the reaction between the refrigerant and the pipe is
suppressed, and accordingly, it is possible to prevent the cooling
performance from degrading and ensure long-term reliability of the
ebullient cooling device.
[0044] Next, the method for connecting pipes will be described in
more detail using FIGS. 5A and 5B. FIGS. 5A and 5B are
cross-sectional views to illustrate a method for connecting pipes
in the cooling device according to the present exemplary
embodiment.
[0045] In the method for connecting pipes according to the present
exemplary embodiment, first, as shown in FIG. 5A, the pipe 250 is
fitted in the first connective projection 221 or the second
connective projection 231 (hereafter, referred to as "a connective
projection 260" simply). Here, the pipe 250 includes the piping
structure of cooling device 100 according to the second exemplary
embodiment, as mentioned above. That is to say, the pipe 250
includes the first tubular part 110 made of metal materials with a
hollow portion through which the refrigerant used in the cooling
device flows, and the second tubular part 120 made of organic
materials with which the first tubular part 110 is covered.
[0046] Next, a pressure is applied from the outer periphery of the
second tubular part 120 toward the center. As shown in FIG. 5B, it
is possible to use a clamping tool such as a clamp 270 in order to
apply the pressure. The pressure enables the metal material
composing the first tubular part 110 to deform and the metal
material to be attached firmly to the connective projection 260 by
a simple process.
[0047] Here, the connective projection 260 can be configured to be
a nipple shape, as shown in FIGS. 5A and 5B. In this case, since
the first tubular part 110 made of metal materials, which composes
the inner layer of the pipe 250, has a small wall thickness, it
undergoes plastic deformation due to the stress concentration at
the convex portions of the nipple shape, and is attached firmly to
the connective projection 260. As a result, it is possible to
suppress the leakage of the refrigerant from the connective
projection 260. Since the pipe 250 according to the present
exemplary embodiment includes, as the outer layer, the second
tubular part 120 made of organic materials such as resin and
rubber, it is possible to maintain the mechanical strength as a
pipe even if the metal material of the inner layer is deformed.
[0048] The present invention is not limited to the above-mentioned
exemplary embodiments and can be variously modified within the
scope of the invention described in the claims. It goes without
saying that these modifications are also included in the scope of
the present invention.
[0049] This application is based upon and claims the benefit of
priority from Japanese Patent Application No. 2011-089347, filed on
Apr. 13, 2011, the disclosure of which is incorporated herein in
its entirety by reference.
DESCRIPTION OF THE CODES
[0050] 10, 100 piping structure of cooling device
[0051] 11, 110 first tubular part
[0052] 120 second tubular part
[0053] 140 metal plate material
[0054] 150 cylindrical jig
[0055] 160 end section
[0056] 170 nozzle
[0057] 200 ebullient cooling device
[0058] 210 refrigerant
[0059] 220 evaporator
[0060] 221 first connective projection
[0061] 230 condenser
[0062] 231 second connective projection
[0063] 240 heat generating unit
[0064] 250 piping
[0065] 251 vapor-phase pipe
[0066] 252 liquid-phase pipe
[0067] 260 connective projection
[0068] 270 clamp
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