U.S. patent application number 15/311751 was filed with the patent office on 2017-04-06 for vacuum heat insulating body, and heat insulating container and heat insulating wall employing same.
This patent application is currently assigned to Panasonic Intellectual Property Management Co., Ltd.. The applicant listed for this patent is Panasonic Intellectual Property Management Co., Ltd. Invention is credited to Tsuyoki HIRAI, Toshiaki HIRANO, Hideji KAWARAZAKI, Tomoaki KITANO.
Application Number | 20170096284 15/311751 |
Document ID | / |
Family ID | 54766428 |
Filed Date | 2017-04-06 |
United States Patent
Application |
20170096284 |
Kind Code |
A1 |
HIRANO; Toshiaki ; et
al. |
April 6, 2017 |
VACUUM HEAT INSULATING BODY, AND HEAT INSULATING CONTAINER AND HEAT
INSULATING WALL EMPLOYING SAME
Abstract
A vacuum heat insulating body includes core material and outer
packing material that vacuum-seals core material. Core material
includes first heat insulating core material and second heat
insulating core material having ventilation characteristics.
Moreover, first heat insulating core material has ventilation
resistance greater than the ventilation resistance of second heat
insulating core material. First heat insulating core material is
configured with an open-cell resin, and second heat insulating core
material is configured with a fiber material or a powder material
having ventilation resistance smaller than the ventilation
resistance of the open-cell resin.
Inventors: |
HIRANO; Toshiaki; (Shiga,
JP) ; KAWARAZAKI; Hideji; (Osaka, JP) ;
KITANO; Tomoaki; (Nara, JP) ; HIRAI; Tsuyoki;
(Shiga, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Panasonic Intellectual Property Management Co., Ltd |
Osaka-shi, Osaka |
|
JP |
|
|
Assignee: |
Panasonic Intellectual Property
Management Co., Ltd.
Osaka-shi, Osaka
JP
|
Family ID: |
54766428 |
Appl. No.: |
15/311751 |
Filed: |
June 2, 2015 |
PCT Filed: |
June 2, 2015 |
PCT NO: |
PCT/JP2015/002773 |
371 Date: |
November 16, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F25D 2201/124 20130101;
B65D 81/3823 20130101; F25D 2201/1262 20130101; F25D 2201/122
20130101; F25D 2500/02 20130101; F25D 2201/14 20130101; F25D 23/065
20130101; F25D 23/06 20130101 |
International
Class: |
B65D 81/38 20060101
B65D081/38; F25D 23/06 20060101 F25D023/06 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 3, 2014 |
JP |
2014-114565 |
Claims
1. A vacuum heat insulating body comprising: a core material; and
an outer packing material that vacuum-seals the core material,
wherein the core material each includes a first heat insulating
core material and a second heat insulating core material having
ventilation characteristics, and wherein the first heat insulating
core material has ventilation resistance greater than ventilation
resistance of the second heat insulating core material.
2. The vacuum heat insulating body of claim 1, wherein the first
heat insulating core material is configured with an open-cell
resin, and wherein the second heat insulating core material is
configured with a fiber material or a powder material having
ventilation resistance smaller than ventilation resistance of the
open-cell resin.
3. The vacuum heat insulating body of claim 2, further comprising:
an interposition that is disposed at a boundary between the first
heat insulating core material and the second heat insulating core
material.
4. The vacuum heat insulating body of claim 3, wherein the
interposition is a resin sheet or a resin film.
5. The vacuum heat insulating body of claim 4, wherein the resin
sheet or the resin film is a resin having no functional group.
6. The vacuum heat insulating body of claim 4, wherein a thickness
of the resin sheet or the resin film ranges from 30 to 500
.mu.m.
7. The vacuum heat insulating body of claim 4, further comprising:
a penetration hole that is formed in the resin sheet or the resin
film.
8. The vacuum heat insulating body of claim 7, wherein a diameter
of the penetration hole ranges from 0.1 to 4 mm.
9. The vacuum heat insulating body of claim 7, wherein the
penetration hole includes a plurality of the penetration holes, and
a pitch between each of the multiple penetration holes ranges from
2 to 90 mm.
10. The vacuum heat insulating body of claim 1, wherein the outer
packing material includes an inner case and an outer case, and
wherein the first heat insulating core material is disposed on an
inner case side.
11. The vacuum heat insulating body of claim 1, wherein an exhaust
hole is provided from a surface of the first heat insulating core
material toward the second heat insulating core material.
12. The vacuum heat insulating body of claim 11, wherein a diameter
of the exhaust hole ranges from 1 to 5 mm.
13. The vacuum heat insulating body of claim 11, wherein the
exhaust hole includes a plurality of the exhaust holes, and a pitch
between each of the multiple exhaust holes is equal to or greater
than 1 mm.
14. The vacuum heat insulating body of claim 3, wherein the second
heat insulating core material is loaded in a packing bag material,
and the packing bag material is configured with the
interposition.
15. The vacuum heat insulating body of claim 1, wherein the second
heat insulating core material is configured with an inorganic fiber
material containing glass wool or rock wool.
16. The vacuum heat insulating body of claim 2, wherein the outer
packing material internally includes a gas suction material which
is sealed together with the core material, and wherein the gas
suction material is disposed on a first heat insulating core
material side inside the outer packing material.
17. The vacuum heat insulating body of claim 1, wherein the outer
packing material is configured with a pair of metal thin plates,
and is configured by fixedly attaching edges of the pair of metal
thin plates to each other and performing vacuum-sealing of an
inside of the pair of metal thin plates.
18. A heat insulating container that can be used as a heat
insulating container retaining a substance of which a temperature
is lower than a normal temperature by at least 100.degree. C., the
heat insulating container comprising: the vacuum heat insulating
body of claim 1, wherein the vacuum heat insulating body is
configured such that one of the first heat insulating core material
and the second heat insulating core material is disposed on a lower
temperature side in the heat insulating container, the one of the
first heating insulating core material and the second heat
insulating core material having lower heat conductivity.
19. A heat insulating wall that can be used as a heat insulating
wall being used in an environment of 0.degree. C. or lower, the
heat insulating wall comprising: the vacuum heat insulating body
claim 7, wherein the vacuum heat insulating body is configured such
that one of the first heat insulating core material and the second
heat insulating core material is disposed on a lower temperature
side in the heat insulating container, the one of the first heating
insulating core material and the second heat insulating core
material having lower heat conductivity.
Description
TECHNICAL FIELD
[0001] The present invention relates to a vacuum heat insulating
body, and a heat insulating container and a heat insulating wall
employing the same.
BACKGROUND ART
[0002] Recently, from the viewpoint of prevention of global
warming, improvement of energy saving is strongly demanded and also
becomes an urgent problem in household electric appliances.
Particularly, in heat-retaining/cold-keeping equipment such as a
refrigerator, a freezer, and a vending machine, from the viewpoint
of efficiently utilizing heat, a heat insulating material having
excellent heat insulating performance is required.
[0003] As general heat insulating materials, materials selected
from a fiber material such as glass wool, and a foamed body such as
urethane foam are employed. In order to improve the heat insulating
performance of the heat insulating materials, the heat insulating
material is required to be increased in thickness. However, in a
case where there is restriction in a space which is to be filled
with the heat insulating material, for example, in a case where
space saving is required or the space is required to be effectively
used, the heat insulating material cannot be applied.
[0004] Therefore, as a high-performance heat insulating material, a
vacuum heat insulating material has been proposed. The vacuum heat
insulating material is a heat insulating body in which a core
material playing a role of a spacer is inserted into an outer
packing material having gas barrier properties, the internal
pressure is reduced, and the inside is sealed.
[0005] Compared to the urethane foam, the vacuum heat insulating
material has heat insulating performance 20 times thereof and has
excellent characteristics in that even if the thickness is reduced,
sufficient heat insulating performance can be obtained.
[0006] Therefore, the vacuum heat insulating material satisfies
customer's demands desiring increased inner volume of a heat
insulating case body and attracts attention as effective means of
achieving improvement of energy saving followed by improvement of
the heat insulating performance.
[0007] For example, in refrigerators, in the heat insulating case
body configuring a refrigerator main body, urethane foam is foamed
in a heat insulating space between inner and outer cases, thereby
filling the heat insulating space. The vacuum heat insulating
material is additionally installed in the heat insulating space,
the heat insulating properties thereof are enhanced, and the inner
volume of the heat insulating case body is increased.
[0008] However, in a case of being used in a refrigerator and the
like, the heat insulating space of the heat insulating case body
generally exhibits a complicated shape. Accordingly, there is
limitation in improving the ratio of the area which can be covered
with the vacuum heat insulating material, that is, the area of the
vacuum heat insulating material occupying in the total heat
transfer area of the heat insulating case body.
[0009] Therefore, for example, a technology has been proposed.
According to the technology, after the heat insulating space of the
heat insulating case body is filled with open-cell urethane through
a blow-molding air feed port of the heat insulating case body and
the open-cell urethane is foamed, the inside of the heat insulating
case body is exhausted and evacuated by a vacuum exhaust apparatus
connected to the air feed port and the heat insulating case body
itself serves as the vacuum heat insulating material (for example,
refer to PTL 1).
[0010] In addition, similar to PTL 1, this applicant has proposed
that the heat insulating space of the heat insulating case body
serving as the refrigerator main body is filled with open-cell
urethane to be foamed and is subjected to vacuum drawing such that
the heat insulating case body itself serves as the vacuum heat
insulating material. Moreover, another technology has been
proposed. According to the technology, closed cells which are
generated when the heat insulating space filled with the open-cell
urethane to be foamed and remain in a skin layer in the vicinity of
an inner surface of a case body are also caused to be open cells
such that the open-cell rate is increased and the heat insulating
properties thereof are further improved (for example, refer to PTL
2).
[0011] As disclosed in PTL 1 and PTL 2 described above, in the heat
insulating case body configured to have the open-cell urethane foam
which fills the heat insulating space so as to be foamed and is
subjected to vacuum sealing, that is, in a vacuum heat insulating
body, as the porosity of the open-cell urethane foam is increased,
the surface area inside the open-cell urethane foam increases.
Since heat from the outside is transferred along the surface of the
open-cell urethane foam, when the surface area increases, the heat
insulating properties are improved.
[0012] When the open cells are formed in alignment in a moving
direction of heat, the heat insulating properties are not improved.
However, since cells are disorderedly formed through foaming, there
is little possibility that the cells are formed in alignment in the
moving direction of heat. Therefore, as the surface area of the
inside increases, the heat insulating properties are improved.
Therefore, according to the technology disclosed in PTL 2 regarding
the vacuum heat insulating body, since the closed cells which
remain in the skin layer in the vicinity of the inner surface of
the case body can also be caused to be open cells and the surface
area thereof can be increased, the heat insulating properties are
improved.
[0013] As described above, in the vacuum heat insulating body which
is disclosed in PTL 2 and is configured to have the open-cell
urethane subjected to vacuum sealing, even if the shape of the
appearance is complicated as the heat insulating case body, the
entire region can be subjected to vacuum heat insulating.
Therefore, for example, when the vacuum heat insulating body is
employed in refrigerators, the heat insulating case body itself can
be reduced in thickness and the inner volume (storage space) can be
further increased.
[0014] In addition, when the vacuum heat insulating body is applied
for the purpose in which the heat insulating properties are
strongly expected even though the shape is not complicated, for
example, a panel for a heat insulating container such as an LNG
storage tank storing an ultra-low temperature substance (for
example, liquefied natural gas (LNG)), and a tank of an LNG
transport tanker, the wall of the heat insulating container can be
reduced in thickness and invasion of heat into the heat insulating
container can be effectively restrained. Therefore, in a case of an
LNG tank, generation of boil off gas (BOG) can be effectively
reduced, and the natural evaporation rate (boil-off rate, BOR) of
LNG can be lowered.
[0015] However, in the above-described vacuum heat insulating body
configured to have the open-cell urethane subjected to vacuum
sealing, the hole diameter of the open cell ranges from 30 to 200
.mu.m, which is extremely small. Therefore, there are problems in
that it takes times to perform vacuum drawing, productivity is
degraded, and the cost increases.
CITATION LIST
Patent Literature
[0016] PTL 1: Japanese Patent Unexamined Publication No.
9-119771
[0017] PTL 2: Japanese Patent No. 5310928
SUMMARY OF THE INVENTION
[0018] The present invention has been made in consideration of the
problems described above, and there is provided a vacuum heat
insulating body in which vacuum drawing efficiency is improved and
productivity is enhanced, and a heat insulating container and a
heat insulating wall employing the same.
[0019] According to the present invention, there is provided a
vacuum heat insulating body including a core material, and an outer
packing material that vacuum-seals the core material. The core
material includes a first heat insulating core material and a
second heat insulating core material having ventilation
characteristics. The first heat insulating core material has
ventilation resistance greater than the ventilation resistance of
the second heat insulating core material.
[0020] In addition, according to the present invention, there is
provided a heat insulating container that can be used as a heat
insulating container retaining a substance of which a temperature
is 100.degree. C. or much lower than a normal temperature, and the
heat insulating container includes the vacuum heat insulating body
described above. The vacuum heat insulating body is configured such
that a heat insulating core material having low heat conductivity
between the first heat insulating core material and the second heat
insulating core material is disposed on a low-temperature side in
the heat insulating container.
[0021] In addition, according to the present invention, there is
provided a heat insulating wall that can be used as a heat
insulating wall being used in an environment of 0.degree. C. or
lower, and the heat insulating wall includes the vacuum heat
insulating body described above. The vacuum heat insulating body is
configured such that the heat insulating core material having low
heat conductivity between the first heat insulating core material
and the second heat insulating core material is disposed on the
low-temperature side of the heat insulating wall.
[0022] Accordingly, when the inside of the heat insulating body is
subjected to vacuum drawing, the first heat insulating core
material having significant ventilation resistance, for example, an
open-cell resin such as open-cell urethane can be reduced in
thickness due to the presence of a fiber material such as the
second heat insulating core material having small ventilation
resistance, for example, glass wool or rock wool. Accordingly, the
path formed of open cells is shortened as much as the thickness is
reduced, and ventilation resistance is reduced. Thus, the vacuum
drawing time can be shortened, and productivity can be
improved.
[0023] In addition, the gas itself gradually coming out from the
inside of the open-cell resin can be reduced as much as the
thickness of the first heat insulating core material having
significant ventilation resistance is reduced, in accordance with
the shortened open-cell path which is shortened due to the reduced
thickness thereof. At the same time, the gas can be dispersed in
the path in its entirety which is configured with open cells, and
deformation caused due to a local pressure rise can also be
restrained. Besides since the amount of gas coming out from the
first heat insulating core material having significant ventilation
resistance is reduced, degradation of the heat insulating
properties can also be restrained.
[0024] In this manner, according to the present invention, it is
possible to provide a vacuum heat insulating body in which vacuum
drawing efficiency is improved and productivity is enhanced, and a
heat insulating container and a heat insulating wall employing the
same.
BRIEF DESCRIPTION OF DRAWINGS
[0025] FIG. 1 is a front view of a vacuum heat insulating case body
of a refrigerator employing a vacuum heat insulating body in a
first exemplary embodiment of the present invention.
[0026] FIG. 2 is a cross-sectional view illustrating a
configuration of a portion of a wall surface of the vacuum heat
insulating case body in the first exemplary embodiment of the
present invention.
[0027] FIG. 3 is a view illustrating the vacuum drawing performance
of the open-cell urethane in the first exemplary embodiment of the
present invention.
[0028] FIG. 4 is a view illustrating the vacuum drawing performance
of the vacuum heat insulating body in the first exemplary
embodiment of the present invention.
[0029] FIG. 5A is a view illustrating an example of the structure
of the vacuum heat insulating body in the first exemplary
embodiment of the present invention.
[0030] FIG. 5B is a view illustrating an example of the structure
of the vacuum heat insulating body in the first exemplary
embodiment of the present invention.
[0031] FIG. 5C is a view illustrating an example of the structure
of the vacuum heat insulating body in the first exemplary
embodiment of the present invention.
[0032] FIG. 5D is a view illustrating an example of the structure
of the vacuum heat insulating body in the first exemplary
embodiment of the present invention.
[0033] FIG. 5E is a view illustrating an example of the structure
of the vacuum heat insulating body in the first exemplary
embodiment of the present invention.
[0034] FIG. 6A is a view illustrating an example of a method of
manufacturing the vacuum heat insulating body in the first
exemplary embodiment of the present invention.
[0035] FIG. 6B is a view illustrating an example of the method of
manufacturing the vacuum heat insulating body in the first
exemplary embodiment of the present invention.
[0036] FIG. 7 is a view illustrating a schematic cross-sectional
configuration of a membrane-type LNG transport tanker including an
inboard tank employing the vacuum heat insulating body, in a second
exemplary embodiment of the present invention.
[0037] FIG. 8 is a view describing a two-layer structure of an
inner surface of the inboard tank of the LNG transport tanker, in
the second exemplary embodiment of the present invention.
[0038] FIG. 9 is an enlarged cross-sectional view of the vacuum
heat insulating body employed in a heat insulating structure body
of the inboard tank of the LNG transport tanker, in the second
exemplary embodiment of the present invention.
[0039] FIG. 10 is a view illustrating an example of the
cross-sectional configuration of a laminated sheet serving as the
outer packing material of the vacuum heat insulating body in the
second exemplary embodiment of the present invention.
[0040] FIG. 11 is a cross-sectional view which is viewed from the
side and illustrates a configuration of the refrigerator employing
the vacuum heat insulating body in a third exemplary embodiment of
the present invention.
[0041] FIG. 12 is a perspective view illustrating a schematic
configuration of a door of the refrigerator in the third exemplary
embodiment of the present invention.
[0042] FIG. 13A is a cross-sectional view illustrating a
configuration of the vacuum heat insulating body of a comparative
example in the third exemplary embodiment of the present
invention.
[0043] FIG. 13B is a cross-sectional view illustrating the
configuration of the vacuum heat insulating body of the comparative
example in the third exemplary embodiment of the present
invention.
[0044] FIG. 14A is a cross-sectional view illustrating a
configuration of a first example of the vacuum heat insulating body
in the third exemplary embodiment of the present invention.
[0045] FIG. 14B is a cross-sectional view illustrating the
configuration of the first example of the vacuum heat insulating
body in the third exemplary embodiment of the present
invention.
[0046] FIG. 15A is a cross-sectional view illustrating a
configuration of a second example of the vacuum heat insulating
body in the third exemplary embodiment of the present
invention.
[0047] FIG. 15B is a cross-sectional view illustrating the
configuration of the second example of the vacuum heat insulating
body in the third exemplary embodiment of the present
invention.
[0048] FIG. 16A is a cross-sectional view illustrating a
configuration of a third example of the vacuum heat insulating body
in the third exemplary embodiment of the present invention.
[0049] FIG. 16B is a cross-sectional view illustrating a
configuration of the third example of the vacuum heat insulating
body in the third exemplary embodiment of the present
invention.
[0050] FIG. 17 is a cross-sectional view illustrating an example of
disposition of the open-cell urethane foam of the comparative
example in the third exemplary embodiment of the present
invention.
[0051] FIG. 18 is a cross-sectional view illustrating a
configuration of the vacuum heat insulating body of the first
example in the third exemplary embodiment of the present
invention.
[0052] FIG. 19 is a cross-sectional view illustrating another
example of the configuration of the vacuum heat insulating body of
the first example in the third exemplary embodiment of the present
invention.
[0053] FIG. 20 is a cross-sectional view illustrating further
another example of the configuration of the vacuum heat insulating
body of the first example in the third exemplary embodiment of the
present invention.
[0054] FIG. 21 is a cross-sectional view illustrating still another
example of the configuration of the vacuum heat insulating body of
the first example in the third exemplary embodiment of the present
invention.
[0055] FIG. 22 is a cross-sectional view illustrating yet another
example of the configuration of the vacuum heat insulating body of
the first example in the third exemplary embodiment of the present
invention.
[0056] FIG. 23 is a view for describing a method of manufacturing
the vacuum heat insulating case body in the third exemplary
embodiment of the present invention.
[0057] FIG. 24 is a view comparing internal pressure of the vacuum
heat insulating body in the third exemplary embodiment of the
present invention.
[0058] FIG. 25 is a view comparing heat conductivity of the vacuum
heat insulating body in the third exemplary embodiment of the
present invention.
[0059] FIG. 26 is a view comparing the internal pressure of the
vacuum heat insulating body in the third exemplary embodiment of
the present invention.
[0060] FIG. 27 is a view comparing the heat conductivity based on a
difference of the thickness of an interposition in the third
example of the vacuum heat insulating body in the third exemplary
embodiment of the present invention.
[0061] FIG. 28 is a view comparing the internal pressure based on a
difference of a hole diameter of a penetration hole of the
interposition in the third example of the vacuum heat insulating
body in the third exemplary embodiment of the present
invention.
[0062] FIG. 29 is a view comparing the internal pressure based on a
difference of a pitch of the penetration hole of the interposition
in the third example of the vacuum heat insulating body in the
third exemplary embodiment of the present invention.
[0063] FIG. 30 is a view comparing the heat conductivity based on a
difference of the hole diameter of an exhaust hole in the third
example of the vacuum heat insulating body in the third exemplary
embodiment of the present invention.
[0064] FIG. 31 is a view comparing compressive strength based on a
difference of the pitch when there are provided multiple exhaust
holes in the third example of the vacuum heat insulating body in
the third exemplary embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0065] Hereinafter, exemplary embodiments of the present invention
will be described with reference to the drawings. The present
invention is not limited by the exemplary embodiments.
First Exemplary Embodiment
[0066] First, a first exemplary embodiment of the present invention
will be described. In the present exemplary embodiment, description
will be given with reference to an example of a case where a heat
insulating case body itself in refrigerator 1 is configured with a
vacuum heat insulating body. However, the exemplary embodiment is
merely an example, and the configuration of the vacuum heat
insulating body of the present exemplary embodiment can also be
used in a part of a door.
[0067] FIG. 1 is a front view of vacuum heat insulating case body 7
of refrigerator 1 employing the vacuum heat insulating body in the
first exemplary embodiment of the present invention, and FIG. 2 is
a cross-sectional view illustrating a configuration of a portion of
a wall surface of vacuum heat insulating case body 7 thereof.
[0068] [Configuration of Refrigerator]
[0069] First, the configuration of refrigerator 1 of the present
exemplary embodiment will be described.
[0070] As illustrated in FIG. 1, refrigerator 1 according to the
present exemplary embodiment includes metal (for example, iron)
outer case 2, and hard resin (for example, ABS resin) inner case 3.
After core material 5 and gas suction material 6 are loaded in heat
insulating space 4 between outer case 2 and inner case 3, and
vacuum sealing is performed, a heat insulating case body
(hereinafter, will be referred to as a vacuum heat insulating case
body) which serves as a refrigerator main body is formed. Here,
"vacuum sealing" includes a state where the pressure of the heat
insulating space is pressure lower than atmospheric pressure.
[0071] Partition panel 8 divides the internal space of vacuum heat
insulating case body 7 into refrigerating compartment 9 on the
upper side and freezing compartment 10 on the lower side. Each of
refrigerating compartment 9 and freezing compartment 10 is provided
with a door (not illustrated). Similar to the vacuum heat
insulating case body described above, these doors are configured by
loading core material 5 and gas suction material 6 in the heat
insulating space, and then, performing vacuum sealing.
[0072] In addition, components (compressor, evaporator, condenser,
and the like) corresponding to the cooling principle thereof are
attached to refrigerator 1. The internal space of vacuum heat
insulating case body 7 is not limited to the example of being
divided into two divisions such as refrigerating compartment 9 and
freezing compartment 10. For example, the internal space may be
divided into multiple storage compartments for different
applications (refrigerating compartment, freezing compartment, ice
compartment, a vegetable compartment, and the like).
[0073] [Configuration of Vacuum Heat Insulating Body]
[0074] Subsequently, vacuum heat insulating case body 7 configured
to be vacuum-sealed, that is, the configuration of the vacuum heat
insulating body will be described by applying FIG. 2.
[0075] As illustrated in FIG. 2, core materials 5 are respectively
vacuum-sealed in heat insulating spaces 4 inside outer case 2 which
is an outer packing material of vacuum heat insulating case body 7,
and inner case 3, as described above. Vacuum-sealed core material 5
is configured with two layers such as first heat insulating core
material 11 and second heat insulating core material 12 having
ventilation characteristics. Here, first heat insulating core
material 11 on one side has ventilation resistance greater than the
ventilation resistance of second heat insulating core material 12,
and second heat insulating core material 12 on the other side has
ventilation resistance smaller than the ventilation resistance of
first heat insulating core material 11. For example, in the present
exemplary embodiment, an open-cell resin is employed as first heat
insulating core material 11 on one side, and a fiber material is
employed as second heat insulating core material 12 on the other
side.
[0076] The open-cell resin which is an example of first heat
insulating core material 11 having relatively great ventilation
resistance is disclosed in detail in PTL 2 of this applicant,
exemplified as the citation literature. Therefore, the disclosure
thereof will be cited and detailed description will be omitted.
However, in brief, the disclosure is as follows.
[0077] In other words, the open-cell resin is configured with
open-cell urethane foam which is integrally foamed and fills heat
insulating space 4 between outer case 2 and inner case 3, for
example, open-cell urethane foam formed through copolymerization
reaction. A number of cells present in a core layer at the center
of heat insulating space 4 communicate with each other through a
first penetration hole. Moreover, cells present in a skin layer in
the vicinity of an interface with respect to each of outer case 2
and inner case 3 in heat insulating space 4 communicate with each
other through a second penetration hole which is formed of powder
having a low affinity with a urethane resin. In this manner, the
open-cell resin of the present exemplary embodiment is an open-cell
resin in which cells in the entire region communicate with each
other through the first penetration hole and the second penetration
hole from the core layer to the skin layer.
[0078] While heat is insulated between outer case 2 and inner case
3, the open-cell resin configuring first heat insulating core
material 11 has functions of supporting outer case 2 and inner case
3 and retaining the shape of vacuum heat insulating case body 7. In
other words, first heat insulating core material 11 contributes to
improvement of physical properties such as the strength and the
rigidity of the vacuum heat insulating body. However, the shape
retention force of first heat insulating core material 11 is
degraded as the porosity increases. Meanwhile, in first heat
insulating core material 11, the heat insulating properties of the
open-cell resin are improved as the porosity increases. Therefore,
in consideration of the heat insulating properties and the
mechanical strength, the porosity of the open-cell resin may be
determined. In the present exemplary embodiment, the porosity is
set to 95% or greater.
[0079] In addition, as cells are small in size, the surface area
inside the open-cell resin increases. Therefore, the heat
insulating properties are improved. In other words, as cells are
small in size, the heat insulating properties of the open-cell
resin are improved. Therefore, in the present exemplary embodiment,
for the sake of both ensuring the strength and improving the heat
insulating properties, the size of cells ranges from 30 .mu.m to
200 .mu.m.
[0080] In addition, second heat insulating core material 12 having
relatively small ventilation resistance is configured with a fiber
material. As second heat insulating core material 12, an
inorganic-based fiber material is particularly employed from the
aspect of heat insulating performance and the like. Specifically,
for example, the inorganic-based fiber material is selected from
glass wool fibers, ceramic fibers, slag wool fibers, rock wool
fibers, and the like. In the present exemplary embodiment, glass
wool fibers (glass fibers having relatively thick fiber diameters)
having the average fiber diameter within a range from 4 .mu.m to 10
.mu.m is additionally burned and is employed.
[0081] Moreover, the fiber material configuring second heat
insulating core material 12 is enclosed in a packing bag material
(not illustrated) having ventilation characteristics and is
configured to be formed along the shape of heat insulating space 4.
The process can be effectively achieved by mixing the fiber
material with a binder material. Even in such a case, the fiber
material is configured to occupy a ratio ranging from at least 5%
to 90%.
[0082] In vacuum heat insulating case body 7 configured as
described above, first heat insulating core material 11 is disposed
so as to face the internal space side serving as the storage
compartment of vacuum heat insulating case body 7, and second heat
insulating core material 12 is disposed so as to face the outer
side, respectively.
[0083] [Method of Manufacturing Vacuum Heat Insulating Case
Body]
[0084] Vacuum heat insulating case body 7 is a vacuum heat
insulating body in which a two-layer core material including first
heat insulating core material 11 formed of the open-cell resin, and
second heat insulating core material 12 formed of the fiber
material are vacuum-sealed. As a method of manufacturing vacuum
heat insulating case body 7, first, a packing bag material
internally having a fiber core material is set inside heat
insulating space 4, and urethane liquid is injected through
urethane liquid filler ports 13 provided at several appropriate
places in outer case 2 or inner case 3 (refer to FIG. 1).
Thereafter, vacuum drawing is performed through urethane liquid
filler ports 13, or vacuum heat insulating case body 7 in its
entirety is input into a vacuum chamber and is subjected to vacuum
drawing. Then, vacuum heat insulating case body 7 is manufactured
by tightly sealing the parts of vacuum drawing ports such as
urethane liquid filler ports 13. When urethane is injected, in
order to smoothly exhaust air inside heat insulating space 4, air
vent holes 14 are dispersedly disposed at least at some appropriate
places in outer case 2 and inner case 3. Similar to urethane liquid
filler ports 13, after being subjected to vacuum drawing, air vent
holes 14 are tightly sealed.
[0085] As the method of manufacturing vacuum heat insulating case
body 7, a method similar to the method disclosed in PTL 2 mentioned
above is employed. In addition, before urethane is injected in the
method, a step of loading second heat insulating core material 12
in heat insulating space 4 is added. Here, vacuum sealing and the
like of heat insulating space 4 may be performed inside the vacuum
chamber. The disclosure in PTL 2 is cited for the detail, and
detailed description thereof will be omitted.
[0086] [Operational effect of Vacuum Heat Insulating Body]
[0087] Subsequently, operational effects of vacuum heat insulating
case body 7 configured as described above, that is, the vacuum heat
insulating body will be described.
[0088] Vacuum heat insulating case body 7 has a core material which
is vacuum-sealed in heat insulating space 4 in a two-layer
structure including first heat insulating core material 11 formed
of the open-cell resin, and second heat insulating core material 12
formed of the fiber material. Accordingly, compared to a case of
configuring the core material with one layer of an open-cell resin
in the related art, the heat insulating performance thereof can be
enhanced.
[0089] For example, according to an experiment, when heat transfer
coefficients .lamda. of a comparative product having only the
open-cell urethane core material and a product of the present
exemplary embodiment having the two-layer core material including a
fiber material and integrally foamed open-cell urethane foam are
compared, heat conductivity .lamda. of the comparative product is
0.007 W/mK, and in contrast thereto, heat conductivity .lamda. of
the product of the present exemplary embodiment is 0.004 W/mK. This
result is caused due to the heat insulating effect of second heat
insulating core material 12 formed of the fiber material in
addition to the heat insulating effect of the open-cell
urethane.
[0090] The above-described experimental result is a result obtained
by preparing a cuboid-shaped core material having a size of
198.times.130 and a thickness of 30 mm in a sealed ABS resin
container at internal pressure of 10 Pa, and measuring the heat
conductivity under the temperature difference of 38.degree.
C./10.degree. C. in the thickness direction.
[0091] Meanwhile, in the present exemplary embodiment, the cells of
the open-cell resin configuring first heat insulating core material
11 range from 30 .mu.m to 200 .mu.m, which is small. Accordingly,
when the inside of heat insulating space 4 is subjected to vacuum
drawing, there is a possibility that the ventilation resistance
(exhaust resistance) of the open-cell resin becomes significant,
thereby requiring a long period of time in order to reduce the
pressure of the internal space of the open-cell resin.
[0092] However, in vacuum heat insulating case body 7 of the
present exemplary embodiment, second heat insulating core material
12 formed of the fiber material is loaded inside heat insulating
space 4 together with first heat insulating core material 11 formed
of the open-cell resin. Accordingly, the thickness of first heat
insulating core material 11 can be thinned as much as the thickness
of second heat insulating core material 12. As a result thereof, an
open-cell path of the open-cell resin configuring first heat
insulating core material 11 is as much shortened as the thickness
is thinned, the ventilation resistance is reduced, and the vacuum
drawing time is shortened. Thus, productivity can be improved.
[0093] FIG. 3 is a view illustrating the vacuum drawing performance
of the open-cell urethane in the first exemplary embodiment of the
present invention.
[0094] Here, internal pressure change A in a case of open-cell
urethane having a thickness of 30 mm, and internal pressure change
B of open-cell urethane having the halved thickness of 15 mm are
illustrated. Here, it is understood that the time taken until the
internal pressure reaches the same value, for example, 200 Pa is
"C" in a case of open-cell urethane A having the thickness of 30
mm, and the time is "D" in a case of open-cell urethane B having
the halved thickness of 15 mm, which is shorter.
[0095] In addition, in vacuum heat insulating case body 7 of the
present exemplary embodiment, the heat insulating core material of
the open-cell resin having significant ventilation resistance can
be reduced in thickness. Moreover, in accordance with the shortened
open-cell path caused due to the reduced thickness, the gas itself
gradually coming out from the inside of the open-cell resin can be
reduced, and the gas can be dispersed over the path in its entirety
configured with the open cells. Accordingly, the heat insulating
performance thereof can be as much restrained from being degraded
as the gas is reduced, and deformation caused due to the local
pressure rise can be as much restrained as the gas is
dispersed.
[0096] Besides, the glass wool, the rock wool, or the like itself
configuring second heat insulating core material 12 of vacuum heat
insulating case body 7 has low heat conductivity, thereby having
favorable heat insulating properties. Accordingly, even if first
heat insulating core material 11 is reduced in thickness, vacuum
heat insulating case body 7 can have excellent heat insulating
properties. Moreover, as described above, in vacuum heat insulating
case body 7, since the amount of the gas coming out from the heat
insulating core material such as the open-cell resin having
significant ventilation resistance can be reduced, the heat
insulating properties can also be restrained from being
degraded.
[0097] FIG. 4 is a view illustrating the vacuum drawing performance
of the vacuum heat insulating body in the first exemplary
embodiment of the present invention.
[0098] As illustrated in FIG. 4, comparative product (2) having the
core material formed of only the open-cell urethane foam, and
product (2) of the present exemplary embodiment having the core
material with the two-layer structure including the fiber material
and the integrally foamed open-cell urethane foam are caused to
have the same dimension in thickness. For example, the products are
exhausted in the vacuum chamber for 30 minutes, and the internal
pressures thereof are measured after 10 days. Consequently, the
internal pressure of comparative product (2) rose to 450 Pa, but in
a case of product (2) of the present exemplary embodiment, the
internal pressure became 250 Pa. There is an effect of restraining
a rise of the internal pressure and deterioration of the heat
insulating performance. It is assumed that the effect is obtained
because the open-cell urethane foam is as much reduced in thickness
as the fiber material in product (2) of the present exemplary
embodiment and the amount of the gas released from the open-cell
urethane foam is reduced.
[0099] The experimental result in this case is a result of the
pressure measurement performed every day elapsed, by using a
spinning rotor gauge with respect to an experiment product obtained
by causing a cuboid-shaped core material having a size of
198.times.130 and a thickness of 30 mm to be exhausted for 30
minutes in a sealed container configured with liquid crystal
polymer and an aluminum foil laminate film, by using a mechanical
booster pump, and performing heat-welding of a film.
[0100] As described above, the heat insulating properties of vacuum
heat insulating case body 7 of the present exemplary embodiment can
be enhanced due to the two-layer structure including first heat
insulating core material 11 formed of the open-cell resin and
second heat insulating core material 12 formed of the fiber
material. Without inhibiting the heat insulating performance
thereof, it is possible to shorten the vacuum drawing time of first
heat insulating core material 11 and to improve productivity.
[0101] In addition, in vacuum heat insulating case body 7, one side
of the heat insulating core material is configured with the
open-cell resin, and the other side of the heat insulating core
material is configured with the fiber material having ventilation
resistance smaller than the ventilation resistance of the open-cell
resin heat insulating core material. Accordingly, as described
above, the open-cell resin is caused to flow into heat insulating
space 4 in a state where the fiber material is input into heat
insulating space 4. Then, the open-cell resin and the fiber
material are integrally foamed and are subjected to vacuum drawing.
It is possible to drastically improve productivity, to reduce the
production cost, and to provide a product at a low price.
[0102] In addition, in accordance with the configuration in which
the fiber material configuring second heat insulating core material
12 is enclosed in the packing bag material having favorable
ventilation characteristics, the fiber material which is flexible
and easily loses its shape can be easily loaded inside heat
insulating space 4. Accordingly, productivity can be further
improved and cost reduction can be achieved. In addition, even if
vacuum heat insulating case body 7 has a complicated shape, the
heat insulating core material can be disposed along the shape, and
thus, the heat insulating core material can also cope with a heat
insulating structure body having a complicated shape.
[0103] In addition, in the present exemplary embodiment, gas
suction material 6 is vacuum-sealed inside vacuum heat insulating
case body 7 together with core material 5. Accordingly, gas which
is contained in the open-cell resin forming first heat insulating
core material 11 and is gradually released, and gas which is
remaining in second heat insulating core material 12 can be
suctioned by gas suction material 6. As a result thereof, a rise of
the internal pressure caused due to the gas can be reliably
restrained, and deformation of vacuum heat insulating case body 7
can be prevented. At the same time, the heat insulating properties
thereof can be favorably maintained over a long period of time.
Particularly, in the present exemplary embodiment, gas suction
material 6 is disposed on the open-cell resin side configuring
first heat insulating core material 11 (refer to FIG. 2). According
to this configuration, gas which is chronologically released from
the open-cell resin can be efficiently suctioned via the open-cell
path, and high heat insulating performance can be maintained by
efficiently preventing a rise of the internal pressure and
restraining degradation of the heat insulating properties.
[0104] As described above, gas suction material 6 plays a role of
suctioning mixed gas of water vapor, air, and the like which
remains in or enters a sealed space such as heat insulating space
4, and gas suction material 6 is not particularly limited. For
example, a chemically suctioned substance such as calcium oxide and
magnesium oxide, a physically suction substance such as zeolite, or
a mixture thereof can be used. In addition, copper ion-exchanged
ZSM-5 type zeolite having suctioning performance with both chemical
suctioning properties and physical suctioning properties and having
a significant suctioning capacity can also be used.
[0105] In the present exemplary embodiment, gas suction material 6
containing the copper ion-exchanged ZSM-5 type zeolite described
above is employed. Accordingly, even if the open-cell resin in
which gas tends to be continuously released as time elapses is
employed as the core material, gas is reliably and continuously
suctioned over a long period of time due to the high suctioning
performance and the significant suctioning capacity which the
copper ion-exchanged ZSM-5 type zeolite has. Thus, it is possible
to reliably prevent a rise of the internal pressure of vacuum heat
insulating case body 7 and restrain degradation of the heat
insulating properties over a long period of time.
[0106] Moreover, as the fiber material configuring second heat
insulating core material 12, the inorganic-based fiber material
such as glass wool and rock wool is employed. Accordingly, the
amount of generated moisture is maintained to be low, and thus, the
heat insulating properties can be favorably retained. In other
words, since the inorganic-based fiber itself has low
water-absorbing properties (hygroscopic properties), the amount of
moisture inside vacuum heat insulating case body 7 can be
maintained to be low. Accordingly, suctioning ability of gas
suction material 6 can be restrained from being reduced due to
suctioned moisture, and gas suction material 6 can conduct a
favorable function of suctioning gas, thereby having favorable heat
insulating performance.
[0107] In addition, since the inorganic-based fiber is burned, for
example, even in a case where vacuum heat insulating case body 7 is
damaged due to some sort of influence, the fiber material does not
greatly swell, and the shape can be retained as vacuum heat
insulating case body 7. For example, when sealing is performed
without burning the inorganic-based fiber, even though it may
depend on other conditions, swelling of vacuum heat insulating case
body 7 at the time of damage can become two to three times before
being damaged. In contrast, when the inorganic-based fiber is
burned, expansion at the time of damage can be restrained within
1.5 times, and thus, expansion at the time of damage can be
effectively restrained, and dimension-retention properties can be
enhanced.
[0108] In vacuum heat insulating case body 7 configured as
described above, first heat insulating core material 11 is disposed
so as to face the internal space of vacuum heat insulating case
body 7, that is, the internal space side serving as the storage
compartment. Accordingly, vacuum heat insulating case body 7 can be
more efficiently heat-insulated, and the heat insulating properties
thereof can be enhanced. The open-cell urethane foam configuring
first heat insulating core material 11 which is subjected to vacuum
drawing has heat conductivity .lamda. lower than heat conductivity
.lamda. of the glass wool, the rock wool, or the like configuring
second heat insulating core material 12 which is similarly
subjected to vacuum drawing. Therefore, according to the
disposition configuration described above, firstly, first heat
insulating core material 11 having low heat conductivity .lamda.
strongly performs heat insulating of a low temperature from the
internal space, and second heat insulating core material 12
positioned outside thereof performs heat insulating at a
low-temperature region where the temperature is relatively high,
after heat insulating is strongly performed by first heat
insulating core material 11 having low heat conductivity .lamda..
Accordingly, even second heat insulating core material 12 having
slightly high heat conductivity .lamda. can strongly perform heat
insulating, and thus, cold air inside the vacuum heat insulating
case body can be efficiently heat-insulated and preserved by
utilizing heat insulating characteristics thereof.
[0109] [Examples of Structure of Vacuum Heat Insulating Body and
Method of Manufacturing Same]
[0110] FIGS. 5A to 5E are views illustrating examples of the
structure of the vacuum heat insulating body, in the first
exemplary embodiment of the present invention. Here, disposition
forms of first heat insulating core material 11 and second heat
insulating core material 12 are illustrated. In FIG. 5A, a surface
of the vacuum heat insulating body on one side, for example, the
bottom surface (or the top surface) is caused to be first heat
insulating core material 11 formed of the open-cell resin. On a
different surface, second heat insulating core material 12 is
disposed. In addition, in FIG. 5B, second heat insulating core
material 12 formed of the fiber core material is sandwiched by
first heat insulating core materials 11 formed of the open-cell
resin. In FIG. 5C, first heat insulating core material 11 formed of
the open-cell resin is disposed around the outer circumference so
as to surround the outer circumference of second heat insulating
core material 12 formed of the fiber core material. In addition, in
FIG. 5D, first heat insulating core material 11 formed of the
open-cell resin is minutely divided, second heat insulating core
materials 12 formed of the fiber core material are disposed there
among. In addition, in FIG. 5E, second heat insulating core
materials 12 formed of the fiber core material are disposed at
corners of first heat insulating core material 11 formed of the
open-cell resin.
[0111] According to the configuration of FIG. 5A, when the heat
insulating case body is subjected to vacuum drawing inside the
vacuum chamber, there is an effect of reducing ventilation
resistance in its entirety such that the core material having
relatively high ventilation resistance is reduced in thickness, by
installing the core material having relatively low ventilation
resistance.
[0112] In addition, in the configuration of FIG. 5B as well,
similar to the configuration of FIG. 5A, there is an effect of
reducing ventilation resistance in its entirety such that the core
material having relatively high ventilation resistance is reduced
in thickness, by installing the core material having relatively low
ventilation resistance.
[0113] In the configurations of FIGS. 5A and 5B described above,
first heat insulating core material 11 formed of the open-cell
resin is disposed on the inner surface in the vicinity of vacuum
heat insulating case body 7, and second heat insulating core
material 12 formed of the fiber core material is configured to be
provided on the outer side thereof. Consequently, in addition to
the effect of reducing ventilation resistance, even if the inner
surface of vacuum heat insulating case body 7 is not a flat surface
and is formed so as to have free irregularities, first heat
insulating core material 11 formed of the open-cell resin can be
formed along the free irregularities thereof. Accordingly, there is
an effect of being able to obtain a vacuum heat insulating case
body in which a heat leak from a gap between the core material and
the case body is restrained.
[0114] In FIG. 5C, similar to the example described above, in
addition to the effect of reducing ventilation resistance in its
entirety, even if all of the six surfaces of the vacuum heat
insulating case body are not flat surfaces and are formed so as to
have free irregularities, first heat insulating core material 11
formed of the open-cell resin can be formed along the free
irregularities thereof. Accordingly, there is an effect of being
able to obtain vacuum heat insulating case body 7 in which a heat
leak from a gap between the core material and the case body is
restrained.
[0115] In addition, according to the configuration of FIG. 5D,
first heat insulating core material 11 is segmented and the path
formed of the open cells can be further shortened. Thus, the vacuum
drawing time can be shortened.
[0116] In addition, according to the configuration of FIG. 5E,
since second heat insulating core materials 12 are disposed at the
corner parts which are unlikely to be filled with the open-cell
resin, there is an advantage that the corner parts can have
favorable heat insulating properties.
[0117] The configuration of FIG. 5E may be realized by being
assembled to any one of the examples of FIGS. 5A to 5D described
above.
[0118] Subsequently, FIGS. 6A and 6B are views illustrating
examples of the method of manufacturing the vacuum heat insulating
body in the first exemplary embodiment of the present invention. As
described above, FIG. 6A illustrates a manufacturing method in
which exhaust pipe 15 is connected to a housing of vacuum heat
insulating case body 7 serving as the outer packing material of the
vacuum heat insulating body and vacuum drawing is performed. In
addition, FIG. 6B illustrates a manufacturing method in which after
a portion, for example, the top surface of the housing of vacuum
heat insulating case body 7 is inserted into vacuum chamber 16
while being in an open state and vacuum drawing is performed, a
sealing plate is welded, bonded, or the like to the opening of the
container for vacuum sealing.
Second Exemplary Embodiment
[0119] Subsequently, a second exemplary embodiment of the present
invention will be described.
[0120] In the present exemplary embodiment, description will be
given regarding an example of employing the vacuum heat insulating
body in the heat insulating structure body of an LNG inboard tank
in an LNG transport tanker.
[0121] FIG. 7 is a view illustrating a schematic cross-sectional
configuration of a membrane-type LNG transport tanker including an
inboard tank employing the vacuum heat insulating body, in the
second exemplary embodiment of the present invention. FIG. 8 is a
view describing the two-layer structure of the inner surface of the
inboard tank of the same LNG transport tanker, and FIG. 8
illustrates a schematic prospective view and a partially enlarged
cross-sectional view thereof. FIG. 9 is an enlarged cross-sectional
view of the vacuum heat insulating body employed in the heat
insulating structure body of the same inboard tank.
[0122] FIG. 7 illustrates heat insulating container 21 which is
configured with the hull itself. The inner side of the container
serving as the tank employs a dual inner and outer heat insulating
structure which is so-called primary heat insulation and secondary
heat insulation.
[0123] In FIGS. 8, and 9, heat insulating container 21 includes
extra-container vessel 22 and in-container vessel 24 which is
provided via intermediate vessel 23 in extra-container vessel 22.
Both in-container vessel 24 and intermediate vessel 23 are
configured with a stainless steel membrane or invar (nickel steel
containing nickel of 36%) and are configured to be strong against
heat contraction.
[0124] First heat insulating case 25 which is the heat insulating
structure body disposed between in-container vessel 24 and
intermediate vessel 23 is configured with wooden case frame body 26
such as a plywood plate of which one surface is open, and powder
heat insulating material 27 such as pearlite with which the inside
of case frame body 26 is filled. Powder heat insulating material 27
may be configured with glass wool or the like, instead of pearlite.
In the present exemplary embodiment, description will be given on
the assumption that pearlite is employed as the powder heat
insulating material.
[0125] Similar to first heat insulating case 25, in second heat
insulating case 28 disposed between intermediate vessel 23 and
extra-container vessel 22, vacuum heat insulating body 29 is laid
on the bottom surface of wooden case frame body 26 of which one
surface is open, and the opening side part is configured to be
filled with powder heat insulating material 27 such as pearlite
similar to first heat insulating case 25.
[0126] In addition, in the present exemplary embodiment, second
heat insulating case 28 is disposed such that vacuum heat
insulating body 29 faces the outer side, that is, extra-container
vessel 22 side.
[0127] FIG. 9 illustrates vacuum heat insulating body 29. Vacuum
heat insulating body 29 has a configuration similar to that in the
first exemplary embodiment. The outer packing material
corresponding to vacuum heat insulating case body 7 is configured
to have a simple flat plate shape. In the configuration, a pair of
recessed metal thin plates 30 and 30 formed of metal or stainless
steel which has low ionization tendency equal to or less than metal
and has high corrosion resistance are fitted to each other, and the
periphery thereof is welded, thereby vacuum-sealing the inside.
[0128] Vacuum heat insulating body 29 of the second exemplary
embodiment also exhibits an effect similar to vacuum heat
insulating case body 7 described in the first exemplary embodiment.
The overlapping description of the effect will be omitted. However,
in a case where vacuum heat insulating body 29 is employed as the
heat insulating material of the LNG inboard tank, metal thin plate
30 serving as the outer packing material that vacuum-seals core
material 5 has remarkably high corrosion-resistant performance
compared to laminated sheet outer packing materials which have been
present in the related art and having a general aluminum-deposited
layer. Accordingly, for example, even if vacuum heat insulating
body 29 is exposed to sea water, vacuum heat insulating body 29 can
be prevented from being corroded and leading to bag-tearing or
damage, and thus, there is an advantage that the reliability
thereof can be enhanced.
[0129] In addition, since core material 5 has the two-layer
structure including first heat insulating core material 11 formed
of the open-cell resin and second heat insulating core material 12
formed of the fiber material such as glass wool, the heat
insulating performance thereof is high. Therefore, the amount of
powder heat insulating material 27 inside second heat insulating
case 28 employing vacuum heat insulating body 29 can be reduced and
second heat insulating case 28 itself can be reduced in thickness,
the capacity of heat insulating container 21 can be as much
increased as the reduction.
[0130] Moreover, similar to the first exemplary embodiment, vacuum
heat insulating body 29 employed as the heat insulating material of
the LNG inboard tank is disposed such that first heat insulating
core material 11 thereof is on a side facing the internal space of
in-container vessel 24, that is, the internal space in which a
substance such as LNG is stored. Accordingly, heat insulating
container 21 can be more efficiently heat-insulated, and the heat
insulating properties thereof can be enhanced. In other words,
according to such a configuration, as described above, firstly,
first heat insulating core material 11 having low heat conductivity
.lamda. strongly performs heat insulating of a low temperature from
the internal space, and second heat insulating core material 12
positioned outside thereof performs heat insulating at a
low-temperature region where the temperature is relatively high,
after heat insulating is strongly performed by first heat
insulating core material 11 having low heat conductivity .lamda..
Accordingly, even second heat insulating core material 12 having
slightly high heat conductivity .lamda. can strongly perform heat
insulating, and thus, cold air inside the vacuum heat insulating
case body can be efficiently heat-insulated and preserved by
utilizing heat insulating characteristics thereof. Particularly,
the example of the present exemplary embodiment is effective since
the temperature of the substance such as LNG stored in heat
insulating container 21 is -162.degree. C., which is an ultra-low
temperature.
[0131] Moreover, since ZSM-5 type zeolite employed as gas suction
material 6 has a chemical suctioning effect, the suctioned gas does
not easily leave. Accordingly, the degree of vacuum inside vacuum
heat insulating body 29 can be favorably retained. Accordingly, in
a case of handling flammable fuel or the like such as LNG, even if
the gas suction material suctions flammable gas due to some sort of
influence, the gas is not released again due to the influence
thereafter such as a rise of temperature, or the like. Thus,
explosion-proof properties of vacuum heat insulating body 29 can be
enhanced and safety can be improved.
Other Modification Examples
[0132] As described above, the forms illustrated in the first
exemplary embodiment and the second exemplary embodiment provide a
high-quality vacuum heat insulating body having high heat
insulating performance at a low price. However, the present
invention is not limited to these examples, and various changes can
be made within the range in which the object of the present
invention is achieved.
[0133] For example, in each of the exemplary embodiments described
above, vacuum heat insulating case body 7 of refrigerator 1 and
vacuum heat insulating body 29 of heat insulating container 21 for
an LNG hull tank are described as examples. However, the vacuum
heat insulating body, and the configuration and the shape of the
heat insulating structure body in which the vacuum heat insulating
body is applied are not limited thereto. In other words, instead of
the shape of a container, the heat insulating structure body may be
employed as a heat insulating wall or the like such as a door which
is substantially flat plate-shaped. In addition, as long as the
heat insulating structure body is a container, the heat insulating
structure body is not necessarily limited to a tank for an LNG
hull. For example, the heat insulating structure body may be
applied to a housing of a portable cooling box, a housing of a
thermostatic oven, a housing of a hot water storage tank, and the
like.
[0134] In addition, in all of the exemplary embodiments described
above, the examples in which the open-cell urethane foam is
employed as the open-cell resin are illustrated. However, the
open-cell resin of the present invention is not limited thereto.
For example, a copolymer resin or the like containing any one of
open-cell phenolic foam, and open-cell urethane foam and open-cell
phenolic foam may be employed. It is effective if the open-cell
resin is an open-cell resin which is disclosed in Japanese Patent
No. 5310928 described above and in which cells are formed in both
the core layer and the skin layer. However, an open-cell resin
which employs only the core layer and in which the skin layer that
is a general skin layer of the open-cell resin having no open cell
is removed may be employed. Similarly, as the heat insulating
material having ventilation resistance smaller than the ventilation
resistance of the open-cell resin, an inorganic-based fiber
material such as glass wool is exemplified. However, the present
invention is not limited to this example. Known organic-based
fibers other than the inorganic-based fiber may be employed, and a
powder material such as pearlite may be employed.
[0135] Moreover, as the outer packing material of the vacuum heat
insulating body, a material configured with an assembly of a metal
outer case and a resin inner case, and a material configured with
an assembly of metal thin plates are exemplified. However, the
present invention is not limited to the examples. A resin molded
product may be employed. For example, laminated sheet 31
illustrated in FIG. 10 may be employed.
[0136] FIG. 10 is a view illustrating an example of the
cross-sectional configuration of laminated sheet 31 serving as the
outer packing material of the vacuum heat insulating body in the
second exemplary embodiment of the present invention.
[0137] Laminated sheet 31 is obtained by integrally laminating
surface protective layer 32, gas barrier layer 33, and heat-welded
layer 34. Surface protective layer 32 is selected from a nylon
film, a polyethylene terephthalate film, a polypropylene film, and
the like. In contrast to metal foil selected from aluminum foil,
copper foil, stainless steel foil, and the like, and a resin film
serving as a base material, gas barrier layer 33 is formed of a
deposited film in which metal or metal oxide is deposited, a film
obtained by further performing known coating processing on the
surface of the deposited film, or the like. Heat-welded layer 34 is
formed of a thermoplastic resin film or the like such as low-
density polyethylene.
Third Exemplary Embodiment
[0138] Subsequently, a third exemplary embodiment of the present
invention will be described.
[0139] FIG. 11 is a cross-sectional view which is viewed from the
side and illustrates a configuration of refrigerator 101 employing
the vacuum heat insulating body in the third exemplary embodiment
of the present invention.
[0140] [Configuration of Refrigerator]
[0141] The configuration of refrigerator 101 of the present
exemplary embodiment will be described.
[0142] As illustrated in FIG. 11, refrigerator 101 according to the
present exemplary embodiment includes metal (for example, iron)
outer case 102, and hard resin (for example, ABS resin) inner case
103. After the core material and the gas suction material are
loaded in heat insulating space 104 between outer case 102 and
inner case 103, and vacuum sealing is performed, a heat insulating
case body (hereinafter, will be referred to as a vacuum heat
insulating case body) which serves as a refrigerator main body is
formed. Here, "vacuum sealing" includes a state where the pressure
of the heat insulating space is pressure lower than atmospheric
pressure. As the configuration of vacuum heat insulating case body
107, it is possible to employ the vacuum heat insulating case body
as is described in the first exemplary embodiment.
[0143] Partition panel 108 divides the internal space of vacuum
heat insulating case body 107 into refrigerating compartment 110 on
the upper side and freezing compartment 109 on the lower side.
Freezing compartment 109 is provided in two stages, and another
refrigerating compartment 110 is additionally provided below
freezing compartment 109. Each of refrigerating compartment 110 and
freezing compartment 109 is provided with door 125. Vacuum heat
insulating case body 113 of the present exemplary embodiment is
configured in the heat insulating space of door 125.
[0144] In addition, components (compressor 117, evaporator 118,
evaporating dish 119, and the like) corresponding to the cooling
principle thereof are attached to refrigerator 101. The internal
space of vacuum heat insulating case body 107 is not limited to the
example described above. For example, the internal space may be
divided into multiple storage compartments for different
applications (refrigerating compartment, freezing compartment, ice
compartment, a vegetable compartment, and the like).
[0145] [Configuration of Vacuum Heat Insulating Body]
[0146] Subsequently, vacuum heat insulating case body 113 of the
present exemplary embodiment, that is, the configuration of the
vacuum heat insulating body will be described.
[0147] FIG. 12 is a perspective view illustrating a schematic
configuration of door 125 of refrigerator 101 in the third
exemplary embodiment of the present invention. In addition, FIGS.
13A and 13B are cross-sectional views illustrating a configuration
of the vacuum heat insulating body of a comparative example in the
same exemplary embodiment. In addition, FIGS. 14A and 14B are
cross-sectional views illustrating a configuration of a first
example of the vacuum heat insulating body in the same exemplary
embodiment. FIGS. 15A and 15B are cross-sectional views
illustrating a configuration of a second example of the vacuum heat
insulating body in the same exemplary embodiment. In addition,
FIGS. 16A and 16B are cross-sectional views illustrating a
configuration of a third example of the vacuum heat insulating body
in the same exemplary embodiment.
[0148] As illustrated in FIG. 12, a vacuum heat insulating material
is formed in the heat insulating space inside outer case 102 and
inner case 103 serving as the outer packing material of vacuum heat
insulating case body 113. In addition, for example, appearance
component 114 such as glass is disposed on the surface side of
outer case 102.
[0149] First, in the comparative example illustrated in FIGS. 13A
and 13B, open-cell urethane foam 121 covered with gas barrier layer
131 is configured in the heat insulating space inside outer case
102 and inner case 103 serving as the outer packing material of
vacuum heat insulating case body 113. Heat-welded layer 132 is
formed at a boundary between inner case 103 and outer case 102, and
air-tightness is retained. In the manufacturing stage, vacuum
drawing is performed through exhaust port 115. Thereafter, exhaust
pipe 116 is sealed, and air-tightness is retained. In this manner,
in the comparative example, as vacuum heat insulating case body
113, the vacuum heat insulating material of one type, in this case,
open-cell urethane foam 121 is employed.
[0150] Subsequently, as illustrated in FIGS. 14A and 14B, in the
first example, open-cell urethane foam 121 and fiber material 122
covered with gas barrier layer 131 are configured in the heat
insulating space inside outer case 102 and inner case 103 serving
as the outer packing material of vacuum heat insulating case body
113. Here, open-cell urethane foam 121 is disposed on appearance
component 114 side of the surface. Heat-welded layer 132 is formed
at a boundary between inner case 103 and outer case 102, and
air-tightness is retained. In the manufacturing stage, vacuum
drawing is performed through exhaust port 115. Thereafter, exhaust
pipe 116 is sealed, and air-tightness is retained. In this manner,
in the first example, as vacuum heat insulating case body 113, the
vacuum heat insulating materials of two types, in this case,
open-cell urethane foam 121 and fiber material 122 are formed. The
first example is an example in which the vacuum heat insulating
material is configured with first heat insulating core material 11
and second heat insulating core material 12 in two layers as
described in the first exemplary embodiment, and the detailed
description will be omitted.
[0151] Subsequently, as illustrated in FIGS. 15A and 15B, in the
second example, similar to the first example described above,
open-cell urethane foam 121 and fiber material 122 covered with gas
barrier layer 131 are configured in the heat insulating space
inside outer case 102 and inner case 103 serving as the outer
packing material of vacuum heat insulating case body 113. Here, the
point that polyethylene film 123 (interposition) is disposed
between open-cell urethane foam 121 and fiber material 122 is
different from the first example. Here, as the interposition, a
resin sheet or a resin film may be employed. It is desirable that
the resin is configured to have no functional group such as OH.
[0152] Here, in the second example, description will be given
regarding the reason that polyethylene film 123 (interposition) is
disposed between open-cell urethane foam 121 which is an example of
a first heat insulating core material, and fiber material 122 which
is an example of a second heat insulating core material.
[0153] As described in the first exemplary embodiment, in the
method of manufacturing vacuum heat insulating case body 113,
firstly, the packing bag material internally having fiber material
122 is set inside the heat insulating space between outer case 102
and inner case 103. Thereafter, the urethane liquid is injected. In
this case, depending on the conditions, the urethane liquid enters
a space between the fibers of the fiber core material, a boundary
layer is formed, and the gas inside thereof cannot be exhausted
well. As a result thereof, there is a possibility that the heat
insulating performance cannot be conducted well. In order to
prevent such a case, there is provided a configuration in which the
first heat insulating core material and the second heat insulating
core material are physically separated from each other by the
interposition in order to cause the core materials to exhibit
performance individually and sufficiently.
[0154] Subsequently, as illustrated in FIGS. 16A and 16B, in the
third example, similar to the second example described above,
open-cell urethane foam 121 and fiber material 122 covered with gas
barrier layer 131 are configured in the heat insulating space
inside outer case 102 and inner case 103 serving as the outer
packing material of vacuum heat insulating case body 113. In
addition, polyethylene film 123 is disposed between open-cell
urethane foam 121 and fiber material 122. Here, in the third
example, the point that multiple penetration holes 124 are provided
in polyethylene film 123 is different from the second example.
[0155] As described above, according to the configuration of the
second example, it is possible to prevent a phenomenon in which the
urethane liquid enters a space between the fibers of the fiber core
material due to the disposed interposition so that the gas therein
cannot be exhausted well. However, since polyethylene film 123
(interposition) does not have ventilation characteristics, air
cannot pass through between the first heat insulating core material
and the second heat insulating core material. Accordingly, on the
contrary, there is a possibility that the interposition may hinder
the exhaust from the vacuum heat insulating body. Therefore, in
this example, penetration hole 124 is provided in order to cause
the interposition to have slight ventilation characteristics.
[0156] In the first example to the third example described above,
the example in which open-cell urethane foam 121 and fiber material
122 covered with gas barrier layer 131 are configured in the heat
insulating space inside outer case 102 and inner case 103 serving
as the outer packing material of vacuum heat insulating case body
113 is illustrated. In each of the examples, the example in which
the first heat insulating core material and the second heat
insulating core material are disposed in the entire region of the
heat insulating space in the width direction is illustrated.
However, the present invention is not limited to this example.
[0157] FIG. 17 is a cross-sectional view illustrating an example of
disposition of open-cell urethane foam 121 of the comparative
example in the third exemplary embodiment of the present
invention.
[0158] In FIGS. 17 to 22, the left side toward the sheet is the
surface side of door 125, and the right side is oriented toward the
inner side of refrigerator 101.
[0159] As illustrated in FIG. 17, in the comparative example, gas
suction material 106 is disposed at a substantial central part of
door 125 on the surface side. Open-cell urethane foam 121 is formed
thoroughly between a space between inner case 103 and outer case
102. In addition, exhaust port 115 is provided at a substantial
central part on the inner side of inner case 103.
[0160] FIG. 18 is a cross-sectional view illustrating a
configuration of the vacuum heat insulating body of the first
example in the third exemplary embodiment of the present
invention.
[0161] As illustrated in FIG. 18, in this example, fiber material
122 (second heat insulating core material) is disposed in the
entire region on the outer side, including the part where gas
suction material 106 is disposed, in the comparative example
illustrated in FIG. 17. In the example illustrated in FIG. 18, the
example in which there is no interposition between the first heat
insulating core material and the second heat insulating core
material is illustrated. However, when polyethylene film 123
(interposition) is disposed between the first heat insulating core
material and the second heat insulating core material, the
configurations of the second example and the third example can be
realized.
[0162] FIG. 19 is a cross-sectional view illustrating another
example of the configuration of the vacuum heat insulating body of
the first example in the third exemplary embodiment of the present
invention.
[0163] As illustrated in FIG. 19, in this example, fiber material
122 (second heat insulating core material) is disposed in the
entire region in the thickness direction from the outer side to the
inner side and a region of a portion in the width direction,
including the part where gas suction material 106 is disposed, in
the comparative example illustrated in FIG. 17. In the example
illustrated in FIG. 19, the example in which there is no
interposition between the first heat insulating core material and
the second heat insulating core material is illustrated. However,
when polyethylene film 123 (interposition) is disposed between the
first heat insulating core material and the second heat insulating
core material, specifically when the second heat insulating core
material is disposed so as to be wrapped by the interposition, the
configurations of the second example and the third example can be
realized.
[0164] FIG. 20 is a cross-sectional view illustrating further
another example of the configuration of the vacuum heat insulating
body of the first example in the third exemplary embodiment of the
present invention.
[0165] As illustrated in FIG. 20, in this example, fiber material
122 (second heat insulating core material) is disposed in a region
of a portion in the thickness direction from the outer side to the
inner side and a region of a portion in the width direction, not
including the part where gas suction material 106 is disposed, in
the comparative example illustrated in FIG. 17. In the example
illustrated in FIG. 20, the example in which there is no
interposition between the first heat insulating core material and
the second heat insulating core material is illustrated. However,
when polyethylene film 123 (interposition) is disposed between the
first heat insulating core material and the second heat insulating
core material, specifically when the second heat insulating core
material is disposed so as to be wrapped by the interposition, the
configurations of the second example and the third example can be
realized.
[0166] FIG. 21 is a cross-sectional view illustrating still another
example of the configuration of the vacuum heat insulating body of
the first example in the third exemplary embodiment of the present
invention.
[0167] As illustrated in FIG. 21, in this example, fiber material
122 (second heat insulating core material) is disposed in a region
at the corner on the outer side, not including the part where gas
suction material 106 is disposed, in the comparative example
illustrated in FIG. 17. In this manner, when fiber material 122 is
disposed, even at the corner on the outer side which is unlikely to
be filled with open-cell urethane foam 121, a sufficient heat
insulating effect can be exhibited. In the example illustrated in
FIG. 21, the example in which there is no interposition between the
first heat insulating core material and the second heat insulating
core material is illustrated. However, when polyethylene film 123
(interposition) is disposed between the first heat insulating core
material and the second heat insulating core material, specifically
when the second heat insulating core material is disposed so as to
be wrapped by the interposition, the configurations of the second
example and the third example can be realized.
[0168] FIG. 22 is a cross-sectional view illustrating yet another
example of the configuration of the vacuum heat insulating body of
the first example in the third exemplary embodiment of the present
invention.
[0169] In the example illustrated in FIG. 22, in addition to the
configuration of the example illustrated in FIG. 18, the example in
which exhaust hole 225 is provided so as to reach fiber material
122 (second heat insulating core material) disposed inside through
exhaust port 115 on the surface of inner case 103 on the inner side
is illustrated. According to this example, as indicated with the
arrow mark in the diagram, when vacuum drawing is performed, the
remaining gas is exhausted through exhaust port 115 via exhaust
hole 225. Thus, the degree of vacuum can be further enhanced.
Multiple exhaust holes 225 may be provided.
[0170] In the example illustrated in FIG. 22, the example in which
exhaust hole 225 is provided in the configuration of FIG. 18 is
illustrated. However, the present invention is not limited to this
example. For example, in addition to the configurations from FIGS.
19 to 21, when exhaust hole 225 is provided, the degree of vacuum
after vacuum drawing can also be enhanced in a similar manner.
[0171] [Method of Manufacturing Vacuum Heat Insulating Case
Body]
[0172] Subsequently, a method of manufacturing vacuum heat
insulating case body 113 of the present exemplary embodiment will
be described.
[0173] FIG. 23 is a view for describing the method of manufacturing
vacuum heat insulating case body 113 in the third exemplary
embodiment of the present invention.
[0174] First, each of inner case 103 and outer case 102 is
manufactured by preparing a sheet having gas barrier properties and
molding the sheet (S301 to S304).
[0175] In addition, separately, the urethane liquid is injected
into a mold and is caused to be foamed (S305). Fiber material 122
(for example, glass wool) is added. In this case, as necessary, the
interposition can be present between the first heat insulating core
material and the second heat insulating core material by wrapping
fiber material 122 with polyethylene film 123, or sandwiching
polyethylene film 123. Thereafter, mold-release from the mold is
performed (S307).
[0176] Inner case 103, outer case 102, and open-cell urethane foam
121 prepared as described above are assembled (S308), and inner
case 103 and outer case 102 are welded to each other, thereby
retaining air-tight properties (S309). The inside of inner case 103
and outer case 102 is subjected to vacuum drawing, or inner case
103 and outer case 102 in their entirety are input into the vacuum
chamber and are subjected to vacuum drawing (S310), and the part of
the port of the exhaust pipe subjected to vacuum drawing is tightly
sealed (S311). Accordingly, the vacuum heat insulating body can be
manufactured.
[0177] [Operational Effect of Vacuum Heat Insulating Body]
[0178] Subsequently, vacuum heat insulating case body 113 which is
prepared as described above, that is, an operational effect of the
vacuum heat insulating body will be described.
[0179] FIG. 24 is a view comparing the internal pressure of the
vacuum heat insulating body in the third exemplary embodiment of
the present invention.
[0180] FIG. 24 illustrates the internal pressures of the
configurations of the first example, the second example, and the
third example in which the internal pressure (state before gas
suction material 106 is functioned) when the vacuum heat insulating
body is configured with only open-cell urethane foam 121
(comparative example) is set to "1" and is relativized.
[0181] As illustrated in FIG. 24, the internal pressure of the
first example (configuration including no interposition between the
first heat insulating core material and the second heat insulating
core material) is higher than the internal pressure when the vacuum
heat insulating body is configured with only the first heat
insulating core material (comparative example). As described above,
the reason is considered as follows. Open-cell urethane foam 121
(first heat insulating core material) enters a space between fiber
materials 122 (second heat insulating core material), and the
boundary layer is formed, thereby hindering remaining gas from
being exhausted during vacuum drawing.
[0182] In contrast, in the second example (configuration including
the interposition between the first heat insulating core material
and the second heat insulating core material) and the third example
(configuration having penetration hole 124 bored in the
interposition), the internal pressures are respectively equal to or
lower than the internal pressure of the comparative example and
equal to or lower than half the internal pressure of the
comparative example. Thus, it is possible to mention that
practicality is high. In the present exemplary embodiment, in the
second example and the third example, the interposition is
polyethylene film 123 having a thickness of 100 .mu.m, and in the
third example, the hole diameter of penetration hole 124 is the
diameter of 1.0 mm, and the pitch is 10 mm.
[0183] FIG. 25 is a view comparing the heat conductivity of the
vacuum heat insulating body in the third exemplary embodiment of
the present invention.
[0184] FIG. 25 illustrates the internal pressures of the
configurations of the first example, the second example, and the
third example in which the heat conductivity when the vacuum heat
insulating body is configured with only open-cell urethane foam 121
(comparative example) is set to "1" and is relativized. In the
second example and the third example, the interposition is
polyethylene film 123 having a thickness of 100 .mu.m, and in the
third example, the hole diameter of penetration hole 124 is the
diameter of 1.0 mm, and the pitch is 10 mm.
[0185] As illustrated in FIG. 25, in all the cases of the first
example, the second example, and the third example, the heat
conductivity lower than the heat conductivity of the comparative
example could be realized. Accordingly, it is possible to mention
that when the first heat insulating core material and the second
heat insulating core material are employed, the heat insulating
performance as the vacuum heat insulating material is improved.
[0186] FIG. 26 is a view comparing the internal pressure of the
vacuum heat insulating body in the third exemplary embodiment of
the present invention.
[0187] FIG. 26 illustrates the internal pressures of the
configurations of the first example, the second example, and the
third example in which the internal pressure (state when gas
suction material 106 is functioned) when the vacuum heat insulating
body is configured with only open-cell urethane foam 121
(comparative example) is set to "1" and is relativized.
[0188] As illustrated in FIG. 26, the internal pressure of the
first example is higher than the internal pressure when the vacuum
heat insulating body is configured with only the first heat
insulating core material (comparative example). As described above,
the reason is considered as follows. Open-cell urethane foam 121
(first heat insulating core material) enters a space between fiber
materials 122 (second heat insulating core material), and the
boundary layer is formed, thereby hindering remaining gas from
being exhausted during vacuum drawing.
[0189] In contrast, in the second example (configuration including
the interposition between the first heat insulating core material
and the second heat insulating core material) and the third example
(configuration having penetration hole 124 bored in the
interposition), the internal pressures are equal to or lower than
half the internal pressure of the comparative example.
[0190] Here, in the example of FIG. 26, all of the values are
values within a practically permissible range. In other words,
vacuum properties of the vacuum heat insulating material in the
first example, the second example, and the third example of the
present exemplary embodiment are within the practically permissible
range after gas suction agent 106 is functioned, and there is no
problem in practicality.
[0191] Subsequently, an optimal configuration in the third example
in a case where polyethylene film 123 which is an example of the
interposition of the vacuum heat insulating material of the present
exemplary embodiment is employed, that is, in a case where
penetration hole 124 is included will be examined.
[0192] FIG. 27 is a view comparing the heat conductivity based on a
difference of the thickness of an interposition in the third
example of the vacuum heat insulating body in the third exemplary
embodiment of the present invention.
[0193] FIG. 27 illustrates that the heat conductivity when the
thickness of the polyethylene film (interposition) is 100 .mu.m is
set to "1" and is relativized. Penetration hole 124 is formed in
the interposition, the hole diameter is 1.0 mm, and the pitch is 10
mm.
[0194] As illustrated in FIG. 27, as the thickness of the
interposition is increased, the heat conductivity is enhanced.
Specifically, when the thickness is increased to be greater than
500 .mu.m, there is an influence of degradation of the heat
insulating performance. On the contrary, when the interposition is
excessively thinned, specifically when the thickness is decreased
to be smaller than 30 .mu.m, there is a possibility that the film
may be broken due to the foam pressure when the open-cell resin is
foamed. The possibility does not depend on the presence or absence
of penetration hole 124.
[0195] In other words, when the thickness of the interposition is
set to range from 30 to 500 .mu.m, the configurations of the second
example and the third example can conduct more performance compared
to the thickness before and after thereof.
[0196] Subsequently, an optimal hole diameter in the third example
in a case where polyethylene film 123 which is an example of the
interposition of the vacuum heat insulating material of the present
exemplary embodiment is employed, that is, in a case where
penetration hole 124 is included will be examined.
[0197] FIG. 28 is a view comparing the internal pressure based on a
difference of the hole diameter of penetration hole 124 of the
interposition in the third example of the vacuum heat insulating
body in the third exemplary embodiment of the present
invention.
[0198] In FIG. 28, the thickness of the polyethylene film
(interposition) is 100 .mu.m, and the hole pitch is 10 mm. The
internal pressure when there is no hole is illustrated to be "1"
and is relativized.
[0199] As illustrated in FIG. 28, it is preferable that penetration
hole 124 of the interposition ranges from 0.1 mm to 4 mm. When the
hole diameter is smaller than 0.1 mm, there is no improvement of
the exhaust efficiency. Meanwhile, when the hole diameter exceeds 4
mm, the open-cell resin (first heat insulating core material)
permeates the fiber material (second heat insulating core
material), and consequently, the internal pressure rises. More
preferably, the internal pressure becomes the lowest when the hole
diameter ranges from 0.3 mm to 2 mm, which is desirable.
[0200] FIG. 29 is a view comparing the internal pressure based on a
difference of a pitch of penetration hole 124 of the interposition
in the third example of the vacuum heat insulating body in the
third exemplary embodiment of the present invention.
[0201] In FIG. 29, the thickness of the polyethylene film
(interposition) is 100 .mu.m, and the hole diameter is 1 mm. In
addition, as illustrated in FIG. 28, the internal pressure when
there is no hole is also set to "1" and is relativized in FIG.
29.
[0202] As illustrated in FIG. 29, it is preferable that the pitch
of penetration hole 124 of the interposition ranges from 2 mm to 90
mm. When the pitch is smaller than 2 mm, the strength of the film
is weakened, and there is a possibility that the film may be broken
due to the foam pressure when the open-cell resin is foamed.
Meanwhile, when the pitch exceeds 90 mm, it is difficult to obtain
the effect of improving the exhaust efficiency.
[0203] FIG. 30 is a view comparing the heat conductivity based on a
difference of the hole diameter of the exhaust hole in the third
example of the vacuum heat insulating body in the third exemplary
embodiment of the present invention.
[0204] In FIG. 30, the number of exhaust holes is set to "one". The
heat conductivity when there is no hole is illustrated to be "1"
and is relativized.
[0205] As illustrated in FIG. 30, from the viewpoint of the heat
conductivity, it is preferable that the hole diameter of the
exhaust hole ranges from 0.3 mm to 5 mm. When the hole diameter is
smaller than 0.3 mm, there is no improvement of the exhaust
efficiency. Meanwhile, when the hole diameter exceeds 5 mm, the
heat conductivity is not lowered, and thus, the heat insulating
performance is not improved.
[0206] FIG. 31 is a view comparing compressive strength based on a
difference of the pitch when there are provided multiple exhaust
holes in the third example of the vacuum heat insulating body in
the third exemplary embodiment of the present invention.
[0207] In FIG. 31, the hole diameter of the exhaust hole is set to
1 mm. The compressive strength when the pitch is 1 mm is
illustrated to be "1" and is relativized.
[0208] As illustrated in FIG. 31, when there are provided multiple
exhaust holes, it is preferable that the pitch is within a range
equal to or greater than 1 mm. The reason is that when the pitch is
smaller than 1 mm, degradation of the compressive strength is
caused.
[0209] In this manner, for those skilled in the art, according to
the description of each of the exemplary embodiments, it is clear
that various modifications of the present invention and other
exemplary embodiments can be made. Therefore, the description of
each of the exemplary embodiments should be interpreted as only an
example and is provided for the purpose of instructing those
skilled in the art regarding preferable forms to execute the
present invention. Without departing from the idea of the present
invention, at least any detail of the structure and the function
can be substantially changed.
[0210] As described above, the vacuum heat insulating body of the
exemplary embodiments of the present invention includes the core
material, and the outer packing material that vacuum-seals the core
material. The core material includes first heat insulating core
material 11 and second heat insulating core material 12 having
ventilation characteristics, and first heat insulating core
material 11 has ventilation resistance greater than the ventilation
resistance of second heat insulating core material 12.
[0211] According to such a configuration, when the inside of the
heat insulating body is subjected to vacuum drawing, the first heat
insulating core material having significant ventilation resistance,
for example, an open-cell resin such as open-cell urethane can be
reduced in thickness due to the presence of a fiber material such
as the second heat insulating core material having small
ventilation resistance, for example, glass wool or rock wool. The
path formed of open cells is shortened as much as the thickness is
reduced, and ventilation resistance is reduced. Thus, the vacuum
drawing time can be shortened, and productivity can be
improved.
[0212] In addition, the gas itself gradually coming out from the
inside of the open-cell resin can be reduced as much as the
thickness of the first heat insulating core material having
significant ventilation resistance is reduced, in accordance with
the shortened open-cell path which is shortened due to the reduced
thickness thereof. At the same time, the gas can be dispersed in
the path in its entirety which is configured with open cells, and
deformation caused due to a local pressure rise can also be
restrained. Besides, since the amount of gas coming out from the
heat insulating core material such as the first open-cell resin
having significant ventilation resistance is reduced, degradation
of the heat insulating properties can also be restrained.
[0213] In addition, the first heat insulating core material may be
configured with the open-cell resin, and the second heat insulating
core material may be configured with the fiber material or the
powder material having ventilation resistance smaller than the
ventilation resistance of the open-cell resin.
[0214] Accordingly, the heat insulating body can be prepared by
causing the open-cell resin to flow into the packing bag material
in a state where the fiber material or the powder material is input
into the packing bag material, and causing the open-cell resin, and
the fiber material or the powder material to be integrally foamed
and to be subjected to vacuum drawing. Accordingly, productivity
can be drastically improved, the production cost can be reduced,
and the heat insulating body can be provided at a lower price.
[0215] In addition, the interposition that is disposed at a
boundary between the first heat insulating core material and the
second heat insulating core material may be configured to be
further included.
[0216] According to such a configuration, when the open-cell resin
is foamed, liquid before being foamed can be prevented from
permeating the fiber material or the powder material. When the
liquid before being foamed permeates, the boundary layer causing
deterioration of the heat insulating performance is formed. In this
case, the fiber material or the powder material may be in a state
of being packed so as to have a bag form.
[0217] In this manner, without inhibiting the filling properties of
the open-cell resin, the outer packing material in its entirety can
be filled.
[0218] In addition, the interposition may be configured to be a
resin sheet or a resin film.
[0219] When such a resin is employed, a heat leak can be
restrained, and the heat insulating performance is not
inhibited.
[0220] In addition, the resin sheet or the resin film may be
configured to be a resin having no functional group.
[0221] According to such a configuration, when a resin having no
functional group (for example, OH group) is employed, it is
possible to prevent deterioration of the heat insulating
performance caused due to a new boundary layer formed with respect
to the first heat insulating core material.
[0222] In addition, the thickness of the resin sheet or the resin
film may be configured to range from 30 to 500 .mu.m.
[0223] As the thickness of the interposition is increased, the heat
conductivity is enhanced. Specifically, when the thickness is
increased to be greater than 500 .mu.m, there is an influence of
degradation of the heat insulating performance. On the contrary,
when the interposition is excessively thinned, specifically when
the thickness is decreased to be smaller than 30 .mu.m, there is a
possibility that the film may be broken due to the foam pressure
when the open-cell resin is foamed. In other words, when the
thickness of the interposition ranges from 30 to 500 .mu.m, more
performance can be conducted compared to the thickness before and
after thereof.
[0224] In addition, the penetration hole that is formed in the
resin sheet or the resin film may be configured to be further
included.
[0225] According to such a configuration, the second heat
insulating core material having small ventilation resistance and
the first heat insulating core material can ventilate through the
penetration hole. Therefore, when vacuum exhaust is performed,
exhaust of the first heat insulating core material can be
efficiently performed through the second heat insulating core
material having small ventilation resistance, and the penetration
hole.
[0226] In addition, the diameter of the penetration hole may range
from 0.1 to 4 mm.
[0227] When the diameter of the penetration hole is smaller than
0.1 mm, there is no improvement of the exhaust efficiency. When the
diameter exceeds 4 mm, there is a possibility that the first heat
insulating core material permeates the second heat insulating core
material. When the diameter ranges from 0.3 to 2 mm, efficiency of
the exhaust can be further improved.
[0228] In addition, there may be provided multiple penetration
holes, and the pitch between each of the multiple penetration holes
may be configured to range from 2 to 90 mm.
[0229] When the pitch is smaller than 2 mm, the strength of the
film is weakened, and there is a possibility that the film may be
broken due to the foam pressure when the first heat insulating core
material is foamed. In addition, when the pitch exceeds 90 mm,
there is no effect of improving the exhaust efficiency.
[0230] In addition, the outer packing material may include the
inner case and the outer case, and the first heat insulating core
material may be configured to be disposed on the inner case
side.
[0231] Accordingly, the inner case of the vacuum heat insulating
body can be configured to be a curved surface other than a flat
surface. The reason is that the first heat insulating core material
is more flexibly deformed so as to fill the inside of the space.
Accordingly, in a case of being employed in the heat insulating
body or the heat insulating wall, it is possible to prevent
degradation of the heat insulating properties caused due to the gap
between the vacuum heat insulating body and the appearance
component or the like.
[0232] In addition, the exhaust hole may be configured to be
provided from a surface of the first heat insulating core material
toward the second heat insulating core material.
[0233] According to such a configuration, the position of the
exhaust port can be freely provided, and the open-cell resin having
significant ventilation resistance can be efficiently exhausted
from the periphery by employing the exhaust hole.
[0234] In addition, the diameter of the exhaust hole may be
configured to range from 1 to 5 mm.
[0235] When the diameter of the exhaust hole is smaller than 0.3
mm, there is no improvement of the exhaust efficiency, and when the
diameter exceeds 5 mm, there is a possibility of causing
degradation of the heat insulating performance.
[0236] In addition, there may be provided multiple exhaust holes,
and a pitch between the multiple exhaust holes may be configured to
be equal to or greater than 1 mm.
[0237] When the pitch is smaller than 1 mm, there is a possibility
of causing degradation of the compressive strength. Meanwhile, when
the pitch is equal to or greater than 1 mm, it is possible to
exhibit the effect of the provided exhaust hole without having
deformation of the container even after vacuum drawing is
performed.
[0238] In addition, the second heat insulating core material may be
loaded in the packing bag material, and the packing bag material
may be configured with the interposition.
[0239] According to such a configuration, in the configuration
including the interposition, the interposition can also be employed
as a packing material packing the second heat insulating core
material.
[0240] In addition, the fiber material may be configured with the
inorganic fiber material containing glass wool or rock wool.
[0241] Accordingly, remaining gas from the fiber material released
inside the vacuum heat insulating body is reduced. Thus,
degradation of the degree of vacuum can be restrained, and the
water-absorbing properties (hygroscopic properties) of the fiber
material itself can be lowered. Therefore, the amount of moisture
inside the vacuum heat insulating body can be maintained to be low,
and the heat insulating properties can be further improved.
[0242] In addition, the outer packing material may internally
include the gas suction material which is sealed together with the
core material, and the gas suction material may be configured to be
disposed on the first heat insulating core material inside the
outer packing material.
[0243] According to such a configuration, when gas remaining inside
the outer packing material is suctioned, the gas which is left
behind vacuum drawing, remains inside the open-cell resin, and
gradually comes out from the open-cell resin can be efficiently
suctioned by the gas suction material. Therefore, it is possible to
prevent the heat insulating body from being deformed and to prevent
the heat insulating properties from being degraded in accordance
with a rise of the internal pressure caused by the gas from the
open-cell resin.
[0244] In addition, the outer packing material may be configured
with a pair of metal thin plates, and may be configured by fixedly
attaching the circumferential edges of the pair of metal thin
plates to each other and performing vacuum-sealing of the
inside.
[0245] Accordingly, in a metal thin plate-made outer packing
material which vacuum-seals the core material has remarkably high
corrosion-resistant performance compared to a multi-layer outer
packing material including an aluminum-deposited layer of a general
vacuum heat insulating material. Therefore, even in a corrosive
environment, for example, even if the outer packing material is
employed as the heat insulating wall of an LNG tanker and the like
and is exposed to sea water, it is possible to prevent the outer
packing material from being corroded and damaged and to
significantly improve the reliability thereof.
[0246] In addition, the heat insulating container of the exemplary
embodiment may be a heat insulating container retaining a substance
of which a temperature is 100.degree. C. or much lower than a
normal temperature. The heat insulating container may include the
vacuum heat insulating body described above, and the vacuum heat
insulating body may be configured such that the heat insulating
core material having low heat conductivity between the first heat
insulating core material and the second heat insulating core
material is disposed on the low-temperature side of the heat
insulating container. In this description, "normal temperature"
denotes an atmospheric temperature.
[0247] Accordingly, firstly, the heat insulating core material
having low heat conductivity strongly performs heat insulating of a
low temperature from a low-temperature substance, and the heat
insulating core material positioned outside thereof performs heat
insulating at the low-temperature region where the temperature is
relatively high, after heat insulating is strongly performed by the
heat insulating core material having low heat conductivity.
Accordingly, a substance inside the container can be efficiently
heat-insulated and preserved by utilizing heat insulating
characteristics thereof.
[0248] In addition, the heat insulating wall of the exemplary
embodiment may be a heat insulating wall that is used in an
environment of 0.degree. C. or lower. The heat insulating wall may
include the vacuum heat insulating body described above, and the
vacuum heat insulating body may be configured such that a heat
insulating core material having low heat conductivity between the
first heat insulating core material and the second heat insulating
core material is disposed on a low-temperature side in the heat
insulating wall.
[0249] Accordingly, firstly, the heat insulating core material
having low heat conductivity strongly performs heat insulating of a
low temperature from a low-temperature substance, and the heat
insulating core material positioned outside thereof performs heat
insulating of the low-temperature region where the temperature is
relatively high, after heat insulating is strongly performed by the
heat insulating core material having low heat conductivity.
Accordingly, efficient heat insulating can be performed by
utilizing heat insulating characteristics thereof.
INDUSTRIAL APPLICABILITY
[0250] As described above, according to the present invention, it
is possible to provide a high-quality vacuum heat insulating body
having high heat insulating performance at a low price,
specifically to exhibit a remarkable effect of improving the vacuum
drawing efficiency and enhancing the productivity. Therefore, the
present invention can be widely applied to a vacuum heat insulating
body from consumer appliances such as a refrigerator to industrial
use such as an LNG storage tank, and a heat insulating container
and a heat insulating wall employing the same, thereby being
useful.
REFERENCE MARKS IN THE DRAWINGS
[0251] 1 REFRIGERATOR [0252] 2 OUTER CASE [0253] 3 INNER CASE
[0254] 4 HEAT INSULATING SPACE [0255] 5 CORE MATERIAL [0256] 6 GAS
SUCTION MATERIAL [0257] 7 VACUUM HEAT INSULATING CASE BODY [0258] 8
PARTITION PANEL [0259] 9 REFRIGERATING COMPARTMENT [0260] 10
FREEZING COMPARTMENT [0261] 11 FIRST HEAT INSULATING CORE MATERIAL
[0262] 12 SECOND HEAT INSULATING CORE MATERIAL [0263] 13 URETHANE
LIQUID FILLER PORT [0264] 14 AIR VENT HOLE [0265] 15 EXHAUST PIPE
[0266] 16 VACUUM CHAMBER [0267] 21 HEAT INSULATING CONTAINER [0268]
22 EXTRA-CONTAINER VESSEL [0269] 23 INTERMEDIATE VESSEL [0270] 24
IN-CONTAINER VESSEL [0271] 25 FIRST HEAT INSULATING CASE [0272] 26
CASE FRAME BODY [0273] 27 POWDER HEAT INSULATING MATERIAL [0274] 28
SECOND HEAT INSULATING CASE [0275] 29 VACUUM HEAT INSULATING BODY
[0276] 30 METAL THIN PLATE [0277] 31 LAMINATED SHEET [0278] 32
SURFACE PROTECTIVE LAYER [0279] 33 GAS BARRIER LAYER [0280] 34
HEAT-WELDED LAYER [0281] 101 REFRIGERATOR [0282] 102 OUTER CASE
[0283] 103 INNER CASE [0284] 104 HEAT INSULATING SPACE [0285] 106
GAS SUCTION MATERIAL [0286] 107 VACUUM HEAT INSULATING CASE BODY
[0287] 108 PARTITION PANEL [0288] 109 FREEZING COMPARTMENT [0289]
110 REFRIGERATING COMPARTMENT [0290] 113 VACUUM HEAT INSULATING
CASE BODY [0291] 114 APPEARANCE COMPONENT [0292] 115 EXHAUST PORT
[0293] 116 EXHAUST PIPE [0294] 117 COMPRESSOR [0295] 118 EVAPORATOR
[0296] 119 EVAPORATING DISH [0297] 121 OPEN-CELL URETHANE FOAM
[0298] 122 FIBER MATERIAL [0299] 123 POLYETHYLENE FILM [0300] 124
PENETRATION HOLE [0301] 125 DOOR [0302] 131 GAS BARRIER LAYER
[0303] 132 HEAT-WELDED LAYER [0304] 225 EXHAUST HOLE
* * * * *