U.S. patent application number 11/902438 was filed with the patent office on 2008-04-03 for insulated container and method of manufacturing the same.
This patent application is currently assigned to NICHIAS CORPORATION. Invention is credited to Toshihiko Kumasaka, Takahiro Ohmura, Atsushi Omura, Keiji Tsukahara, Kunihiko Yano.
Application Number | 20080078771 11/902438 |
Document ID | / |
Family ID | 38796218 |
Filed Date | 2008-04-03 |
United States Patent
Application |
20080078771 |
Kind Code |
A1 |
Tsukahara; Keiji ; et
al. |
April 3, 2008 |
Insulated container and method of manufacturing the same
Abstract
The present invention provides an insulated container capable of
reducing manufacturing costs, obtaining a sufficient heat
insulating effect, and capable of being applied to various
installation spaces having different shapes, and a method of
manufacturing the same. The insulated container, which stores a
liquid at a maintained temperature, includes: an internal container
(1) which stores the liquid therein and includes a liquid inlet (5)
and a liquid outlet (5); a sheet-like covering material (3) which
houses the internal container (1); and an insulated space which is
provided between the covering material (3) and the internal
container (1) and is filled with a heat insulating material (2) and
a gas adsorbent (4) to be decompressed. In the insulated container,
a filler (6) is provided to a joint section (7) between the
covering material (3) and the internal container (1).
Inventors: |
Tsukahara; Keiji; (Tokyo,
JP) ; Yano; Kunihiko; (Tokyo, JP) ; Kumasaka;
Toshihiko; (Tokyo, JP) ; Ohmura; Takahiro;
(Tokyo, JP) ; Omura; Atsushi; (Tokyo, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
NICHIAS CORPORATION
Minato-Ku
JP
|
Family ID: |
38796218 |
Appl. No.: |
11/902438 |
Filed: |
September 21, 2007 |
Current U.S.
Class: |
220/592.2 |
Current CPC
Class: |
F01P 2011/205 20130101;
B65D 81/3846 20130101; B65D 81/3823 20130101 |
Class at
Publication: |
220/592.2 |
International
Class: |
B65D 81/38 20060101
B65D081/38 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 28, 2006 |
JP |
2006-266038 |
Jun 20, 2007 |
JP |
2007-163023 |
Claims
1. An insulated container which stores a liquid at a maintained
temperature, comprising: an internal container which includes a
liquid inlet and a liquid outlet and stores the liquid; a
sheet-like covering material which houses the internal container;
and an insulated space which is provided between the internal
container and the covering material, is filled with a heat
insulating material and a gas adsorbent and is decompressed.
2. An insulated container according to claim 1, wherein: the
internal container is made of one of stainless steel and a resin;
and the covering material comprises a laminated film including an
adhesive layer.
3. An insulated container according to claim 1, further comprising
a filler which is provided at a joint section between the internal
container and the covering material.
4. An insulated container according to claim 1, wherein: the heat
insulating material comprises an inorganic fiber selected from the
group consisting of glass wool, rock wool, and a ceramic fiber; and
the gas adsorbent comprises calcium oxide, a barium-lithium alloy,
and cobalt oxide.
5. A method of manufacturing an insulated container which stores a
liquid at a maintained temperature, the insulated container
comprising: an internal container which includes a liquid inlet and
a liquid outlet and stores the liquid inside thereof; and a
sheet-like covering material which houses the internal container
and forms an insulated space between the internal container and the
sheet-like covering material, the method comprising: filling a heat
insulating material and a gas adsorbent in the insulated space to
be decompressed; and providing a filler at a joint section between
the covering material and the internal container to join the
covering material and the internal container to each other.
6. A method of manufacturing an insulated container which stores a
liquid at a maintained temperature, the insulated container
comprising: an internal container which includes a liquid inlet and
a liquid outlet and stores the liquid inside thereof; and a
sheet-like covering material which houses the internal container
and forms an insulated space between the internal container and the
sheet-like covering material, the method comprising: filling a heat
insulating material and a gas adsorbent in the insulated space to
be decompressed; and preheating an inner side of a joint section
between the covering material and the internal container which are
joined to each other to thermally weld the joint section.
7. An insulated container according to claim 2, further comprising
a filler which is provided at a joint section between the internal
container and the covering material.
8. An insulated container according to claim 2, wherein: the heat
insulating material comprises an inorganic fiber selected from the
group consisting of glass wool, rock wool, and a ceramic fiber; and
the gas adsorbent comprises calcium oxide, a barium-lithium alloy,
and cobalt oxide.
9. An insulated container according to claim 3, wherein: the heat
insulating material comprises an inorganic fiber selected from the
group consisting of glass wool, rock wool, and a ceramic fiber; and
the gas adsorbent comprises calcium oxide, a barium-lithium alloy,
and cobalt oxide.
10. An insulated container according to claim 7, wherein: the heat
insulating material comprises an inorganic fiber selected from the
group consisting of glass wool, rock wool, and a ceramic fiber; and
the gas adsorbent comprises calcium oxide, a barium-lithium alloy,
and cobalt oxide.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The priority application numbers JP2006-266038 and
2007-163023 upon which this patent application is based are hereby
incorporated by the reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an insulated container for
storing a liquid at a maintained temperature, and a method of
manufacturing the same. In particularly, the present invention
relates to an insulated container for storing a long life coolant
(LLC) for a vehicle engine at a maintained temperature, and a
method of manufacturing the same.
[0004] 2. Description of the Related Art
[0005] In recent years, improvement in fuel efficiency is expected
as global energy saving and environmental measures, and a cold
start pattern at the start of an engine (fuel consumption at start
of engine) is modeled as an indicator of a fuel consumption
mode.
[0006] Up to now, there is known a method in which a long life
coolant (LLC) for a vehicle engine is stored in the insulated
container at the maintained temperature, and the LLC whose
temperature is maintained is circulated through the engine when
starting the engine, thereby promoting warming-up of the engine (JP
2006-104974 A).
[0007] In addition, as a similar method of maintaining the
temperature of a liquid within a container, there is known a method
in which a bag is formed using a metal foil or a laminated film
having a metal vapor deposition portion, a heat insulating material
having voids formed therein is provided at an inner side of the
bag, and a vacuum heat insulating material for decompression and
sealing is formed around the container (JP 2002-058604 A).
[0008] In order to improve the fuel consumption when starting the
engine, the insulated container for a vehicle engine is required to
have a high thermal insulating performance for maintaining the
temperature of the LLC, which is raised by preheating of the
engine, until re-start of the engine, and there is a need to reduce
manufacturing costs. In order to install the insulated container in
an engine compartment, there is a strong demand for space saving
and adaptability to various engine compartments having different
shapes.
[0009] In the insulated container disclosed in JP 2006-104974 A, an
insulated space which is in a vacuum state is provided between an
internal container made of a metal and an external container made
of a metal, and the internal container and the external container
are integrally formed through welding or a spinning process.
[0010] However, in a case where the internal container and the
external container are made of a metal such as stainless steel, the
manufacturing costs are increased, and heat is easily conducted
from a metal joint section between the internal container and the
external container, due to a heat bridge effect, which makes it
difficult to obtain a sufficient heat insulating effect. In
addition, stainless steel whose thickness is as thin as 1 mm or
less is used so as to control the heat bridge, and the shape of the
container is limited to a cylindrical shape so as to prevent
deformation of the container due to a difference between the
internal pressure and the atmospheric pressure, which limits design
of the container which is formed into a shape suitable for an
installation space, and also limits types of vehicles onto which
the container is mounted.
[0011] On the other hand, in an insulation structure disclosed in
JP 2002-058604 A, a plate-like vacuum heat insulating material is
formed, and then the vacuum heat insulating material is wound
around a side surface of the container. Accordingly, a gap (air
space) is liable to be formed between the container and the vacuum
heat insulating material. Further, in a case where an internal
container to be housed in the container has a columnar shape, it is
difficult to apply the insulation structure to the insulating
container with a high thermal insulating performance which is
required for the insulated container for a vehicle engine, because
of heat loss from gaps formed between mating surfaces at end
portions of the vacuum heat insulating material which is wound
around the side surface of the container, or joint sections between
a cover portion, a bottom portion, and a side surface portion.
SUMMARY OF THE INVENTION
[0012] The present invention has been made in view of the
above-mentioned problems, and an object of the present invention is
to provide an insulated container capable of reducing manufacturing
costs, obtaining a sufficient heat insulating effect, and being
applied to various installation spaces having different shapes, and
a method of manufacturing the same.
[0013] In order to attain the above-mentioned object, according to
a first aspect of the present invention, there is provided an
insulated container which stores a liquid at a maintained
temperature, including: an internal container which includes a
liquid inlet and a liquid outlet and stores the liquid; a
sheet-like covering material which houses the internal container;
and an insulated space which is provided between the internal
container and the covering material and is filled with a heat
insulating material and a gas adsorbent to be decompressed.
[0014] In the insulated container according to a second aspect of
the present invention, the internal container is made of stainless
steel or a resin, and the covering material is a laminated film
including an adhesive layer.
[0015] According to a third aspect of the present invention, the
insulated container further includes a filler which is provided to
a joint section between the internal container and the covering
material.
[0016] In the insulated container according to a fourth aspect of
the present invention, the heat insulating material is an inorganic
fiber selected from the group consisting of glass wool, rock wool,
and a ceramic fiber, and the gas adsorbent includes calcium oxide,
a barium-lithium alloy, and cobalt oxide.
[0017] According to a fifth aspect of the present invention, there
is provided a method of manufacturing an insulated container which
stores a liquid at a maintained temperature, the insulated
container including: an internal container which includes a liquid
inlet and a liquid outlet and stores the liquid inside thereof; and
a sheet-like covering material which houses the internal container
and forms an insulated space between the internal container and the
sheet-like covering material, the method including: filling a heat
insulating material and a gas adsorbent in the insulated space to
be decompressed; and providing a filler to a joint section between
the covering material and the internal container to join the
covering material and the internal container to each other.
[0018] According to a sixth aspect of the present invention, there
is provided a method of manufacturing an insulated container which
stores a liquid at a maintained temperature, the insulated
container including: an internal container which includes a liquid
inlet and a liquid outlet and stores the liquid inside thereof; and
a sheet-like covering material which houses the internal container
and forms an insulated space between the internal container and the
sheet-like covering material, the method including: filling a heat
insulating material and a gas adsorbent in the insulated space to
be decompressed; and preheating an inner side of a joint section
between the covering material and the internal container which are
joined to each other to thermally weld the joint section. In this
case, the preheating can be performed by employment of a heating
method using a space heater, a heating method with heated air, or
the like.
[0019] According to aspects of the present invention, the following
effects can be obtained. [0020] (1) The internal container and a
vacuum heat insulating layer are integrally formed with the
sheet-like covering material, thereby making it possible to form a
high efficiency vacuum heat insulating layer. As a result, for
example, leakage of heat from the interior of the container, which
contains the LLC and is disposed in an engine compartment for
vehicle, is reduced, thereby obtaining an effect in which a fuel
efficiency of an automobile is improved, and the fuel efficiency at
the time of starting the engine is especially improved. [0021] (2)
In addition, because the internal container and the vacuum heat
insulating layer are integrally formed with the sheet-like covering
material, the present invention can be applied to internal
containers having various shapes, and the internal container can be
designed and the heat insulating layer can be formed so as to
correspond to any type of installation spaces. For example, even in
such a limited space as an engine compartment for vehicle, it is
possible to design to install the insulated container for storing
the LLC at the maintained temperature. [0022] (3) Further, a
stainless steel container is used as the internal container, and an
inexpensive laminated film is used as the covering material,
thereby making it possible to reduce the manufacturing costs to a
large extent. [0023] (4) The filler is provided to the joint
section between the internal container and the covering material,
thereby making it possible to form the insulated space with ease
and reliability. [0024] (5) The inner side of the joint section of
the internal container is preheated, thereby reliably heat-sealing
the internal container and the covering material with each
other.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] In the accompanying drawings:
[0026] FIG. 1 is a cross-sectional diagram illustrating an example
of an insulated container according to the present invention;
[0027] FIG. 2 is a cross-sectional diagram illustrating another
example of the insulated container according to the present
invention;
[0028] FIG. 3 is a cross-sectional diagram illustrating a joint
section between an internal container and a covering material,
which is provided with a filler (cross-sectional diagram taken
along the line A-A of FIG. 1 in which overlapped portion of
covering material is omitted);
[0029] FIG. 4 is a cross-sectional diagram illustrating an example
of a shape of the filler;
[0030] FIG. 5 is a cross-sectional diagram illustrating another
example of a shape of the filler;
[0031] FIG. 6 is a cross-sectional diagram illustrating another
example of a shape of the filler;
[0032] FIG. 7 is a schematic diagram of a laminated film serving as
the covering material;
[0033] FIG. 8 is an explanatory diagram illustrating a method of
joining the joint section between the internal container and the
covering material;
[0034] FIG. 9 is an explanatory diagram illustrating preheating of
the joint section between the internal container and the covering
material; and
[0035] FIG. 10 is a graph illustrating measurement results of
Example 1 and Comparative Example 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] Examples of an insulated container according to an
embodiment of the present invention are illustrated in FIGS. 1 and
2. According to the embodiment of the present invention, an
internal container 1 and a vacuum heat insulating layer are
integrally formed by the use of a sheet-like laminated film 3
serving as a covering material. Accordingly, the insulated
container according to the present invention can be applied to
various internal containers 1 having different shapes, and a high
efficiency vacuum heat insulating layer can be formed. FIG. 3 is a
cross-sectional diagram illustrating a joint section 7 between the
internal container 1 and the covering material 3, which is provided
with a filler 6. It should be noted that, in FIG. 1, an overlapped
portion of the covering material 3 is omitted, but the overlapped
portion of the covering material 3 as illustrated in FIG. 3 is left
with a certain length so as to maintain airtightness.
[0037] In order to achieve the structure, according to the present
invention, the sheet-like laminated film 3 is directly thermally
welded to a liquid inlet/outlet 5 of the internal container 1 so as
to maintain a vacuum state of the heat insulating layer. At a
triple point at which two laminated films 3 and the internal
container 1 are in contact with each other, a gap is liable to be
formed, which makes it difficult to maintain the vacuum state. For
this reason, in the present invention, the filler 6 is used to
enable thermal welding without forming the gap. The filler 6 is
produced using a thermoplastic resin, which is made of the same
material as or a different material from an adhesive layer 11 of
the laminated film 3 and is melted at the time of thermal welding
to fill in the gap. And the filler 6 is formed as a protrusion
obtained by processing the joint section 7 of the internal
container 1; or is obtained by joining, to the joint section 7 of
the internal container 1, a structure which is made of a different
material and is capable of controlling generation of the gap. FIGS.
4 to 6 each illustrate an example of the shape of the filler 6.
[0038] Next, the internal container 1 whose material is made of a
metal or a resin is used. In view of heat insulating properties,
the internal container 1 is desirably made of a metal having a
large heat capacity, and particularly, the internal container 1 is
desirably made of stainless steel having low heat conductivity.
However, in a case where manufacturing costs have to be further
reduced, or the internal container whose shape is difficult to make
of a metal, the internal container 1 can be made of a resin. The
resin is selected and used from the group consisting of
acrylonitrile butadiene styrene copolymer (ABS), acrylonitrile
styrene copolymer (AS), EEA resin (EEA), epoxy resin (EP), ethylene
vinyl acetate polymer (EVA), ethylene vinyl alcohol copolymer
(EVOH), liquid crystal polymer (LCP), MBS resin (MBS), melamine
formaldehyde (MMF), polyamide (PA), polybutyrene terephtalate
(PBT), polycarbonate resin (PC), polyethylene (PE), polyethylene
terephatlate (PET), tetrafluoroethylene perfluoroalkyl vinyl ether
polymer (PFA), plyimide (PI), polymethylmethacrylate (PMMA),
polyacetal resin (POM), polypropyrene (PP), polyphtalamide (PPA),
polyphenylenesulfide resin (PPS), polystyrene (PS),
polytetrafluoroethylene (PTFE), polyurethane (PU), polyvinyl
alcohol (PVA), polyvinyl chloride (PVC), and polyvinylidene
chloride (PVDC). However, because the resin has larger gas
permeability than a metal, in a case where the resin is selected as
the material of the internal container, a gas barrier layer is
desirably formed to control the gas permeability, and a metal layer
is suitably formed by plating. As a result, a degree of vacuum of
the vacuum heat insulating layer can be maintained for a long
period of time.
[0039] FIG. 7 is a schematic diagram of the laminated film 3
serving as the covering material. The laminated film 3 has a
multi-layer structure including a protective layer 8, a protective
layer (base material layer) 9, a gas barrier layer 10, and an
adhesive layer 11 which are formed in the stated order. In
particular, the adhesive layer 11 is desirably made of ethylene
vinyl alcohol copolymer, nylon, polyvinyl alcohol, polyvinylidene
chloride, and polyester, which can be adhered to an adhesive layer
or a metal surface and have low gas permeability. Particularly,
ethylene vinyl alcohol copolymer is suitably used. Further, in
order to prevent leakage of a gas from an interface between the
adhesive layer 11 and the gas barrier layer 10 to the heat
insulating layer, a metal vapor deposition layer is formed in
advance on one surface of a film made of ethylene vinyl alcohol
copolymer, which is effective in maintaining the degree of
vacuum.
[0040] The thickness of the laminated film according to the
embodiment of the present invention is not particularly limited as
long as the laminated film can be produced without any
inconveniences. For example, the thickness may be set to 45 to 120
.mu.m, and preferably 60 to 100 .mu.m.
[0041] A gas permeation rate of the laminated film according to the
embodiment of the present invention is not particularly limited as
long as the degree of vacuum of the insulated space can be
maintained during a desired time period. For example, the oxygen
permeation rate, which is measured using JIS-K7126-1, may be
1.1.times.10.sup.-11 m.sup.3/m.sup.2sMPa or lower, and preferably
1.1.times.10.sup.-12 m.sup.3/m.sup.2sMPa or lower.
[0042] In the embodiment of the present invention, a decompressed
space formed in an insulated space is controlled to be a pressure
lower than the atmospheric pressure (decompressed state) so as to
improve heat insulating properties. For example, the pressure may
be set to 0.01 to 100 Pa, and preferably 0.1 to 10 Pa.
[0043] A known insulating material can be used as an insulating
material to be included in the insulated space. Examples of the
insulating material include an organic porous body such as
polystyrene foam, a compact including ceramic powder such as
calcium silicate, silica, or alumina, and an inorganic fibrous
insulating material made of glass wool, rock wool, or a ceramic
fiber. In particular, it is desirable to use glass wool which has
an average fiber diameter of 5 .mu.m or smaller, and whose
adsorption moisture is removed in a high temperature atmosphere.
The insulating material may be used singly, or a combination of two
or more insulating materials may be used.
[0044] When the heat insulating layer is used for a long period of
time, there is a fear that the degree of vacuum will be lowered by
a gas generated from the heat insulating material 2, a gas
permeating the resin of the joint section, or the like. In order to
prevent lowering of the degree of vacuum, it is necessary to use an
adsorbent 4 for adsorbing the gas provided inside the heat
insulating layer. It is desirable to use, as the adsorbent 4,
calcium oxide which mainly adsorbs water, a barium-lithium alloy
which mainly adsorbs oxygen and nitrogen, and cobalt oxide which
mainly adsorbs hydrogen. In a case where the adsorbents are
individually used to be provided in the heat insulating layer,
there arises a problem in that the barium-lithium alloy adsorbs
water generated from the heat insulating material, and a capability
of adsorbing hydrogen and nitrogen is lowered, which is not
intended in the present invention. Therefore, it is suitable to
employ a three-layered structure (not shown) including a
barium-lithium alloy layer serving as an intermediate layer, a
calcium oxide layer, and a cobalt oxide layer.
[0045] In order to thermally weld the laminated film 3 to the
internal container 1, there is used a sealer which is formed into
the shape of the liquid inlet/outlet 5 which corresponds to the
joint section 7 of the internal container 1. In the case of using
the internal container 1 made of a metal, a sheet made of the same
material as the adhesive layer 11 is desirably wound around the
internal container joint section 7 in advance so that the adhesive
layer 11 can be thermally welded to the internal container joint
section 7 with ease and a distance between the internal container 1
and an aluminum foil serving as the gas barrier layer 10 is
increased to thereby increase a heat resistance of the joint
section 7. In this case, the heat resistance is increased as an
amount of sheet to be wound becomes larger. However, because an
amount of gas permeating the resin of the adhesive layer 11 is
increased according to a thickness of the sheet, the amount of
sheet to be wound is desirably 50 .mu.m or less.
[0046] In addition, at the triple point at which two laminated
films 3, 3 and the internal container 1 are in contact with each
other, a gap is liable to be formed. Accordingly, the filler 6 is
desirably provided thereto in advance. As described above, the
filler 6 is obtained by: joining a rod made of the same material as
the adhesive layer 11 of the laminated film 3 to the joint section
7; joining a rod made of the same material as the internal
container 1 to the joint section 7; or joining a protrusion
obtained by processing the joint section 7 of the internal
container 1 or a rod made of a different material to the joint
section 7 (see FIG. 3). Specifically, the filler may have a shape
of a circular cross-section as illustrated in FIG. 4, have a shape
of a triangular cross-section as illustrated in FIG. 5, or may be
formed on an entire peripheral surface of the joint section as
illustrated in FIG. 6. However, the present invention is not
limited thereto.
[0047] The glass wool 2 is wound around the internal container 1 to
which the filler 6 is formed. The amount of the glass wool 2 to be
wound in this case is determined depending on a thermal insulating
performance required for the insulated container (which will be
described in detail in Example 2).
[0048] As illustrated in FIG. 8, with respect to the liquid
inlet/outlet 5 of the internal container 1 around which the glass
wool 2 is wound, between the two laminated films 3, 3 with adhesive
layers 11 (FIG. 7) facing each other the internal container 1 is
provided at a position where the fillers 6 are positioned at the
triple points and these are thermally welded with the sealer.
[0049] The sealer has a high heat-resistance rubber 12 made of
fluorine which is molded into the shape of the joint section, and
includes a ribbon-like metal heater 13 and a glass cloth 14 that
are provided on the high heat-resistance rubber 12. As heat-sealing
conditions for the sealer, a state where the laminated films 3 are
pressed onto the internal container 1 is maintained for 6 seconds
or more at a temperature which is 20.degree. C. higher than a
melting point of the adhesive layer 11. Note that, in a case of
using the internal container 1 made of a metal, the heat
conductivity and the heat capacity of the internal container 1 are
large when only the heater of the sealer is used. This makes it
difficult to set the temperature of the laminated films 3 at the
internal container joint section 7 to be equal to a fusion bonding
temperature of the adhesive layer. Accordingly, it is necessary to
preheat the internal container joint section 7 by using an
auxiliary heater (see FIG. 9). In the preheating illustrated in
FIG. 9, a heated air nozzle 15 is inserted to the inner side of the
internal container joint section 7, and a heated air 16 is
introduced into the inside thereof to heat the internal container
joint section 7. However, the present invention is not limited
thereto, and a heating system such as an electric heater can also
be used.
[0050] The internal container 1 and the laminated films 3, 3 are
heat-sealed, and then both surfaces of the laminated films 3, 3 are
thermally welded. Also in this case, in the same manner as
described above, the state where the laminated films 3, 3 are
pressed onto the internal container 1 is maintained for 6 seconds
or more at a temperature which is 20.degree. C. higher than the
melting point of the adhesive layer 11. The both surfaces of the
laminated films 3, 3 are heat-sealed to form the laminated films 3,
3 into a bag shape. After that, the getter material 4 serving as a
gas adsorbent is filled therein.
[0051] In this state, the container thus obtained is put in a
vacuum chamber, and an interior of the chamber is evacuated and
internal pressure thereof is set to 10 Pa or lower. A bottom
portion of the container, which is the remaining side to be sealed,
is heat-sealed under the above-mentioned conditions to form the
vacuum heat insulating layer. The interior of the chamber is
evacuated so that the heat conductivity of the heat insulating
material is lowered, and an amount of heat radiated from the
interior of the insulated container is reduced. The heat
propagating in the interior of the fiber heat insulating material
is a sum of heat propagating through a gas, heat propagating
through a solid, and heat propagating by means of radiation. The
internal gas is eliminated by decompression, thereby suppressing
the heat propagating through the gas, lowering the entire heat
conductivity, and reducing the radiated heat amount.
EXAMPLE 1
[0052] An example of a manufacturing method for the insulated
container according to the present invention will be described in
detail below, but the present invention is not limited thereto.
[0053] As the internal container 1, there was used a rectangular
parallelepiped container which was made of polyethylene and had an
internal volume of about 2.6 L and a coating thickness of 8 mm. On
one surface of the internal container 1, the liquid inlet/outlet 5
having an outer diameter of 18.5 mm, an inner diameter of 13 mm,
and a height of 30 mm was provided. In addition, at a position of
the liquid inlet/outlet 5, which was 10 mm apart from an upper
surface of the liquid inlet/outlet 5, the filler 6 made of a
polyethylene resin having a height of 10 mm as illustrated in FIG.
5 was formed. An ABS resin was formed on the surface of the
internal container 1 excluding the portion on which the filler 6 is
provided. After that, an electroless nickel plating layer was
formed and then an electrolytic copper plating layer was formed to
thereby obtain the gas barrier layer.
[0054] As the covering material 3, there was used a laminated film
having a multi-layer structure including a polyethylene
terephatlate layer (having a thickness of 12 .mu.m) serving as the
protective layer 8, a nylon layer (having a thickness of 15 .mu.m)
serving as the protective layer 9, an aluminum foil (having a
thickness of 6 .mu.m) serving as the gas barrier layer 10, and a
polyethylene resin layer (having a thickness of 50 .mu.m) serving
as the adhesive layer 11.
[0055] White wool manufactured by ASAHI FIBER GLASS Co., Ltd. was
used as the fiber heat insulating material 2, and COMBO3GETTER
manufactured by SAES Getters was used as the gas adsorbent 4
(getter material).
[0056] Around the container made of polyethylene serving as the
internal container 1, the glass wool was coated with a thickness so
as to reach a position of the lower surface of the filler 6
provided to the liquid inlet/outlet 5 of the internal container 1.
The density of the glass wool in this case was about 0.25
g/cm.sup.2 with respect to a surface area of the internal container
1. Next, the adhesive surfaces of two laminated films serving as
the covering materials 3 are positioned to face the fillers 6
provided to the liquid inlet/outlet 5 of the internal container 1.
Then, the position of the joint section 7 was adjusted so as to
obtain the temperature of 160.degree. C with the sealer as
illustrated in FIG. 8, and was pressurized for 6 seconds. After
that, side surfaces of the laminated films serving as the covering
materials 3 were pressurized for 6 seconds at the temperature of
160.degree. C. to be heat-sealed with a typical sealer in the same
manner as described above. The two covering materials 3 (laminated
films) thus heat-sealed with the internal container 1 were
thermally welded on three sides thereof excluding the bottom
portion, to be formed into a bag shape. In addition, the container
was left for 24 hours in an oven at the temperature of 120.degree.
C. to evaporate the water contained in the glass wool.
[0057] After the water was evaporated, the container thus contained
was carried in the chamber with an argon atmosphere, and one getter
material (about 7 g) serving as the gas adsorbent 4 was provided
from the bottom portion at which the covering material 3 was
opened, and then the interior of the chamber is decompressed to 10
Pa. Then, the opened portion of the covering material 3 was joined
to be sealed by using a heater provided in the vacuum chamber. In
this manner, the insulated container having a vacuum heat
insulating layer having a thickness of 10 mm was produced. The
method described above is Example 1.
[0058] Hot water of about 100.degree. C. was poured into the
insulated container according to Example 1, was left for about 10
minutes, and then displaced. The hot water of about 100.degree. C.
was poured into the insulated container again, a thermocouple was
inserted from the liquid inlet/outlet, and the liquid inlet/outlet
was closed with a rubber stopper. By setting a time point at which
the water temperature within the insulated container became
95.degree. C. as a start, the water temperature was continuously
measured for 12 hours.
COMPARATIVE EXAMPLE 1
[0059] According to Comparative Example 1, there was employed an
insulated container having a duplex tube structure made of a metal,
in which a stainless plate having a thickness of about 0.5 mm is
used for the internal container and the external container, and a
vacuum heat insulating layer was provided between the internal
container and the external container. The liquid inlet of the
insulated container according to Comparative Example 1 has an
insulation structure with a cover material, which suppresses
radiation of heat from the liquid inlet. Hot water of about
100.degree. C. with the same volume as Example 1 was poured into
the insulated container according to Comparative Example 1, left
for 10 minutes, and then discharged. Hot water of about 100.degree.
C. was poured into the insulated container again, the thermo-couple
was inserted in the insulated container, and then the liquid inlet
was closed. By setting a time point at which the water temperature
within the insulated container became 95.degree. C. as a start, the
water temperature was continuously measured for 12 hours.
(Measurement Results)
[0060] Measurement results according to Example 1 and Comparative
Example 1 are shown in FIG. 10.
[0061] In Example 1, the hot water of 95.degree. C. (contained in
the insulated container according to the present invention) was
maintained at about 83.degree. C. after the hot water was left for
12 hours, while in Comparative Example 1, the hot water of
95.degree. C. was maintained at about 78.degree. C. after the hot
water was left for 12 hours. As a result, it has been proved that
the insulated container according to Example 1 has a heat
insulation property equal to or higher than that of Comparative
Example 1. It should be noted that, in the insulated container used
in Comparative Example 1, which has a duplex tube structure made of
a metal and is a commercially available thermos type container, the
internal container and the external container are each formed of a
stainless steel plate having a thickness of about 0.5 mm, and a
vacuum heat insulating layer is provided between the internal
container and the external container. In addition, the liquid inlet
of the insulated container according to Comparative Example 1 has
the insulation structure, which suppresses radiation of heat from
the liquid inlet.
EXAMPLE 2
[0062] Next, a specific example in which the amount of the glass
wool 2 to be wound is determined based on the heat insulating
performance required for the insulated container will be described
as Example 2.
[0063] For example, water of 95.degree. C. was poured into each of
insulated containers respectively including a vacuum heat
insulating layer having a winding amount of 0.25 g/cm.sup.2 with a
thickness of 10 mm, a vacuum heat insulating layer having a winding
amount of 0.13 g/cm.sup.2 with a thickness of 5 mm, and a vacuum
heat insulating layer having a winding amount of 0.38 g/cm.sup.2
with a thickness of 15 mm, and the insulated containers were left
for 12 hours to measure the water temperature thereof. As a result,
the water temperature of the insulated container with the thickness
of 5 mm was about 70.degree. C., that of the insulated container
with the thickness of 10 mm was about 78.degree. C., and that of
the insulated container with the thickness of 15 mm was about
82.degree. C.
EXAMPLE 3
[0064] Example 3 shows examples of combinations of the materials
for the insulated container according to the present invention, but
the present invention is not limited thereto.
EXAMPLE (A)
[0065] Inner vessel: stainless steel [0066] Filler: stainless steel
(processing) [0067] Adhesive layer: ethylene-vinyl alcohol
copolymer
EXAMPLE (B)
[0067] [0068] Inner vessel: stainless steel [0069] Filler:
ethylene-vinyl alcohol copolymer [0070] Adhesive layer:
ethylene-vinyl alcohol copolymer
EXAMPLE (C)
[0070] [0071] Inner vessel: polyethylene [0072] Filler:
polyethylene [0073] Adhesive layer: polyethylene
EXAMPLE (D)
[0073] [0074] Inner vessel: polypropyrene [0075] Filler:
polypropyrene [0076] Adhesive layer: polypropyrene
EXAMPLE (E)
[0076] [0077] Inner vessel: ABS resin [0078] Filler: ABS resin
(processing)+metal coating film [0079] Adhesive layer:
ethylene-vinyl alcohol copolymer The insulated container according
to the present invention can be used as an insulated container for
storing a liquid at a maintained temperature, and particularly, can
be applied to an insulated container for storing a long life
coolant (LLC) for a vehicle engine.
[0080] In addition, the insulated container according to the
present invention can be used as an insulated container such as an
electric pot, or a cold-insulation container for liquid gas or the
like.
* * * * *