JP7209467B2 - Insulated container and manufacturing method of the insulated container - Google Patents

Description

The present invention relates to an insulated container and a method for manufacturing an insulated container.

Conventionally, there has been a heat-insulating container in which foamed resin, heat-insulating fibrous material, or heat-insulating powder is generally filled within the wall thickness of the container body (well-known technology).

As a material to be filled in the wall thickness of the container body, the foamed resin is often used mainly to ensure low-temperature insulation, but it is not suitable for high-temperature insulation. Some of them are suitable for high-temperature insulation, but it is difficult to sufficiently satisfy high heat insulation performance in both low-temperature and high-temperature ranges simply by filling them within the wall thickness.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a container that has further improved insulation performance in both low and high temperature ranges as compared to conventional heat insulating containers.

A first characteristic configuration of the heat insulating container of the present invention is provided with a container main body portion that forms a storage space in which a material to be insulated can be stored, and a doorway of the main body portion through which the material to be insulated can be taken in and out of the storage space. The container main body is formed by inserting the first double-shell steel container into the second outer-frame steel container, 1. The double-shell steel container comprises a first pressure-reduced airtight layer that is depressurized by accommodating a first spacer member between the peripheral walls of the inner steel container inserted into the outer steel container, A gap space between the first double-shell steel container and the second outer-frame steel container accommodates a second spacer member and is sealed under atmospheric pressure, and the lid portion includes: A second pressure-reduced airtight layer is provided within the thickness thereof with a third spacer member interposed therebetween, and the first pressure-reduced airtight layer contains silicon dioxide ( SiO ₂ ) and silicon carbide (SiC) powder, which is heat-resistant and has high heat-retaining performance against high temperatures. In the gap space between the second outer-frame steel container and the second spacer member, a heat-insulating molded plate obtained by compression-molding a mixture containing fumed silica (SiO ₂ ) and silicon carbide (SiC), and , and filled with the mixed powder, and an elastic heat insulating molded body is provided at the upper end of the gap space between the first double-shell steel container and the second outer frame steel container. It is in the place where it was filled all the way around.

According to the first characteristic configuration of the present invention, the first double-shell steel container forming the first pressure-reduced airtight layer and the second outer-frame steel container filled with heat-insulating powder formed outside the first double-shell steel container. A storage space for the material to be insulated is formed inside the double structure, and the storage space is closed with a lid portion that constitutes the second pressure-reduced airtight layer, thereby further improving the heat insulation performance. can.
A heat-insulating molded plate formed by compression-molding a mixture containing fumed silica and silicon carbide provided between the first double-shell steel container and the second outer-frame steel container, and an airgel powder made of silicon dioxide. By constructing the second spacer member from the mixed powder of the silicon carbide powder and the silicon carbide powder, the gap between the first double-shell steel container and the second outer frame steel container can be maintained even when the temperature changes. can be maintained for a long period of time, and can maintain high insulation performance.
That is, for example, in the case of only the mixed powder, when the load from the first double-shell steel container and its contents is applied, the porous mixed powder itself is crushed to form the first double-shell steel container. There is a risk that the distance from the second outer frame steel container cannot be maintained, and the mixed powder may move and become uneven due to the movement and vibration of the heat insulating container, which may also reduce the heat insulating performance. For example, if only the heat-insulating plate is used, the expansion and contraction phenomenon of the first double-shell steel container and the second outer-frame steel container due to the temperature change causes bending external force to act on the heat-insulating plate and destroy it. There is a risk that it will not be able to maintain its shape and the heat insulation performance will be reduced. On the other hand, by forming the second spacer member from a combination of the heat insulating molded plate and the mixed powder, the space between the first double-shell steel container and the second outer frame steel container can be reduced to the heat insulating molded plate. While maintaining the temperature, the mixed powder acts as a cushioning member and absorbs the expansion and contraction deformation of the first double-shell steel container and the second outer frame steel container due to temperature changes. can prevent breakage and maintain good insulation performance.
Outside the first double-shell steel container, the upper end portion of the gap between the second outer frame steel container and the outer frame steel container is filled with an elastic heat-insulating molded body over the entire circumference, so that the container rolls over. Even so, the insulating material filled between the first double-shell steel container and the second outer-frame steel container can be prevented from overflowing, and the heat insulating performance can be maintained.

Airgel powder made of silicon dioxide has high heat insulating performance against low temperatures, and silicon carbide powder has high heat insulating performance against high temperatures. It is possible to widely improve the thermal insulation performance for

In a second characteristic configuration of the present invention, an opening is provided in the lid, and the plurality of In order to form an airtight space between the glass plates, a vacuum multi-layered glass is attached to the opening, in which the airtight space is decompressed while the entire circumference is airtightly sealed.

According to the second characteristic configuration of the present invention, the condition inside the container body can be observed through the vacuum multi-layered glass attached to the lid, and heat insulation management for the material to be heat-insulated contained in the container body can be performed satisfactorily.

In a third characteristic configuration of the present invention, the heat insulating molded plate is installed against the inner surface of the second outer frame steel container, and the heat insulating molded plate and the side surface of the first double-shell steel container are is filled with the mixed powder.

The characteristic configuration of the method for manufacturing the insulated container of the fourth aspect of the present invention is that, in forming the first double-shell steel container, heat-resistant and heat-insulating filled with the first spacer member made of the mixed powder having a specific viscosity, and heating the first double-shell steel container in a dryer to create a gap between the inner steel container and the outer steel container. Before the powder-filled space reaches normal temperature, the powder-filled space is hermetically sealed to form the first reduced-pressure airtight layer.

According to the fourth characteristic configuration of the present invention, the first double-shell steel container is heated in a dryer so that the powder-filled space between the inner steel container and the outer steel container reaches normal temperature. By previously sealing the powder-filled space in an airtight state, the first reduced-pressure airtight layer can be formed more easily than, for example, when the pressure is reduced by a vacuum pump.

(a) and (b) are photographs of a completed heat insulating container. It is a photograph which shows a part of manufacture description of steel containers. (a) and (b) are explanatory diagrams for assembling the double-shell steel container. (a) and (b) are photographs showing an assembly procedure, and (c) is a top view of a container main body. (a) and (b) are photographs showing an assembly procedure, and (c) is a top view of a container main body. (a) and (b) are photographs for measuring airtightness. (a), (b), and (c) are photographs showing the assembly procedure. A photograph of a perspective view of a container main body. (a), (b), (c), and (d) are photographs showing changes in the steel sheet. Photograph of the liquid tightness test. (a), (b), (c), and (d) are photographs showing the assembly procedure of the container main body, and (e) is a longitudinal sectional view of the container main body. (a) is a photograph of a container main body, and (b) is a longitudinal sectional view of the container main body. Photo of the lid. (a) is a photograph of the lid, and (b) is a photograph of the finished heat-insulating container. (a), (b), and (c) are photographs of what is to be accommodated in the accommodation space. (a), (b), and (c) are photographs of the experimental apparatus. (a) and (b) are photographs showing experimental conditions. Flow and photos showing the flow of manufacturing an insulated container. A photograph showing the manufacturing procedure of the insulated container. A photograph showing the manufacturing procedure of the insulated container. A photograph showing the manufacturing procedure of the insulated container. FIG. 2 is a partially cutaway plan view of the heat insulating container; FIG. 2 is a vertical cross-sectional view of an insulated container; Partially enlarged vertical cross-sectional view of the heat insulating container. Partially enlarged vertical cross-sectional view of the heat insulating container. Partially enlarged vertical cross-sectional view of the heat insulating container. Partially enlarged vertical cross-sectional view of the heat insulating container. 4 is a graph showing pressure dependence of thermal conductivity in each filling material filled in the first reduced-pressure airtight layer. 1 is an overall perspective view of an insulated container of the present invention; FIG. 1 is a vertical cross-sectional view of an insulated container of the present invention; FIG. BRIEF DESCRIPTION OF THE DRAWINGS It is assembly explanatory drawing of an outer frame steel-made container, (a) is a longitudinal cross-sectional view of an outer-frame steel-made container, (b) is a longitudinal cross-sectional view in the middle of assembling a high-performance heat insulating material to an outer-frame steel-made container. It is an explanatory diagram of assembling a double-shell steel container with an outer-frame steel container, (a) is a longitudinal sectional view in the middle of fitting the double-shell steel container into the outer-frame steel container, and (b) is a cross-sectional view of both. It is a longitudinal cross-sectional view after assembly. Explanatory drawing for assembling a double shell steel container to an outer frame steel container, (a) is a longitudinal sectional view showing the upper gap between the two, (b) is a state in which the upper gap between the two is filled with a heat insulating paint board. It is a vertical cross-sectional view of.

An embodiment of the present invention will be described below with reference to the drawings.

[Fireproof cold insulation box]
1. Outline of Insulation Box A complete insulation box 20 as a container main body having an accommodation space S capable of accommodating a material to be insulated is shown in FIGS. are shown in FIGS. 22 to 27 and 30. FIG. As shown in FIGS. 22 and 23, the insulation box 20 has a cubic shape with internal dimensions of 300×300×300 mm, insulation thickness of 20 mm, and external dimensions of 340×340×340 mm. The same applies hereinafter) and an upper lid 16 . As shown in FIG. 27, in order to form the first reduced-pressure airtight layer 23 containing the first spacer member and reduced in pressure, the first reduced-pressure airtight layer 23 is filled with the SiC-added silica airgel powder 10, and is made of double-shell steel. A container (first container) 11 is provided with an outer frame steel container (second container) 18 as shown in FIGS. A high-performance heat insulating material 9 and a SiC-added silica airgel powder 10 are inserted and filled between and as a second spacer member, and the inner surface of the double-shell steel container 11 inside the heat insulating box is coated with heat insulating paint 13 and The waterproof material 14 was painted. Also, as shown in FIGS. 22 and 24, vacuum glass 2 was used as the upper lid 16 so that the state inside the heat insulating box could be observed. In addition, the heat insulation box 20 is made of two bodies (20A and 20B) of the same structure, and the heat insulation box 20A is for extreme cold knitting with a test temperature of -196 ° C. and for long knitting with a test temperature of 39.7 ° C. The heat insulation box 20B was used for the 500° C. burning test.
18 and 19 to 21 show the manufacturing flow of the heat insulating box 20 and the manufacturing procedure of the heat insulating box 20, respectively. The details of the insulation box fabrication procedure are described below.

1.1 Double-shell steel container (1) Assembly of double-shell steel container The double-shell steel container 11 shown in Figs. The inner and outer steel containers of the double shell steel container 11 were made separately. As shown in FIG. 2, each steel container was carefully assembled by Tig welding on five surfaces except for the top surface while cooling the back surface of the weld with water so that distortion would not occur during welding. As shown in FIGS. 3(a) and 3(b), the inner steel container was inserted into the outer steel container of the double shell, and the pair of facing faces of the four faces of the upper opening was 10 mm wide and 10 mm thick. The outer steel container and the inner steel container were fixed by Tig welding using 1.6 mm steel.

(2) Filling of SiC-added silica airgel powder Silica airgel (manufactured by Cabot Corporation (Germany), trade name P-200, average particle size 0.01 to 1.2 mm) and silicon carbide (SiC, Yakushima Denko) as a radiation reducing material Co., Ltd., an average particle size of 2 μm) and SiC-added silica airgel powder 10 mixed at a ratio of 100:20 (weight ratio) are used as a first spacer, as shown in FIGS. It was poured into the bottom and side spaces of the heavy-shell steel container 11 from two sides of the top opening to fill up to the top of the side.

(3) Closing the upper surface of the double-shell steel container
As shown in FIGS. 5(a), (b), and (c), after the filling of the SiC-added silica airgel powder 10 was completed, the remaining two surfaces of the upper surface of the double-shell steel container 11 were made to have a width of 10 mm and a thickness of 1.5 mm. It was closed by Tig welding using a 6 mm steel plate. In addition, one of the two steel plates has a nut attached to the M5 bolt hole in order to attach a pressure gauge for airtightness confirmation, and the M5 nut is on the side of the SiC-added silica airgel powder 10. was closed by Tig welding.

(4) Pressure reduction and airtightness test in double-shell steel container The double-shell steel container 11 was placed in a dryer set at 130 ° C. for 30 minutes, and the internal gas (air ) was released. After 30 minutes had passed, the double-shell steel container 11 was taken out, and as shown in FIG. The pressure in the double-shell steel container 11 decreases as the temperature of the double-shell steel container 11 decreases, and as shown in FIG. After confirming that the value remained the same even after the passage of time, the airtightness test of the double-shell steel container 11 was completed.
In addition, in FIG. 28 of Reference 1, by lowering the internal pressure by one order of magnitude from the atmospheric pressure (10 ⁵ Pa), the thermal conductivity of silica airgel can be reduced to about half, λ=0.007 W/mK. It is shown.

[Reference 1]
New development of utilization of unused thermal energy and points of designing/adopting thermal energy-saving new materials and new products [emphasizing profitability] Supplementary volume Subject: Development of high-strength airgel exhibiting excellent thermal insulation performance, Kazuyoshi Kanamori (Graduate School, Kyoto University) Department of Chemistry, Graduate School of Science), etc., P.289

(5) Application of heat-insulating paint to the inner surface of the double-shell steel container (inner surface of the heat-insulating box) and re-pressurization The inner surface (fifth surface) of the double-shell steel container 11 on the side was coated three times with a heat insulating paint 13 made by adding glass fiber and silica airgel powder to a special inorganic resin using a trowel and a rubber spatula. After that, the pressure gauge of the double-shell steel container 11 was removed, and the heat-insulating paint 13 was completely dried and the pressure inside the double-shell steel container 11 was reduced again. placed. After 30 minutes had passed, the double-shell steel container 11 was taken out, and as shown in FIGS. The final dry film thickness of the heat insulating paint 13 was confirmed using an electromagnetic film thickness meter. If the dry film thickness was thin, it was reapplied.

(6) Construction of waterproof material In the extreme cold (liquid nitrogen -196°C) test, water is stored in the insulation box 20 and conducted.
For this reason, after completely drying the heat insulating paint 13 and sealing the double shell steel container 11, a waterproof material 14 (Soflan Co., Ltd.) is placed on the coated surface of the heat insulating paint 13 as shown in FIGS. Soflanate 5050 (trade name, made by Wiz, polyurethane resin) was applied.
The waterproof material 14 was applied using a rubber spatula to a dry film thickness of 0.5 mm.

1.2 Outer Frame Steel Container (1) Assembly of Outer Frame Steel Container As shown in FIGS. It consists of 27 mm steel plates (thin plates) 15, and the 5 surfaces excluding the top surface are carefully Tig-welded while cooling the back surface of the weld with water so that distortion does not occur during welding, as shown in Fig. 9(a). .
In the burning knitting test, since the steel plate is directly in contact with the iron plate heated to 500° C., as shown in FIG. , occurs.
As shown in FIG. 9(d), a steel material with a thin bottom plate having a thickness of 0.27 mm had a float of about 1 mm even under the heating condition of 500° C., satisfying the float condition of 5 mm or less during the test. For the steel plate (thin plate) 15 with a bottom thickness of 0.27 mm, as shown in FIG. I used what I dropped.

(2) Liquid nitrogen (LN2, -196°C) leakage test of outer frame steel container 196°C), liquid tightness (LN2 resistance) is required. As shown in FIG. 10, whether or not liquid nitrogen leaked from the outer surface to the inner surface of the welded portion of the outer frame steel container 18 was confirmed by immersing it in a container filled with liquid nitrogen.

(3) Insulation work between double-shell steel container and outer frame steel container As shown in FIGS. As shown in FIG. 11(a), a high-performance heat insulating material 9 sliced to a thickness of 5 mm was placed on the side surface and a thickness of 6.33 mm on the bottom surface. Incidentally, the high-performance heat insulating material 9 on the side was applied to −10 mm from the top as shown in FIG. 11(e).
The high-performance heat insulating material 9 is manufactured by Krosaki Harima Co., Ltd. (trade name: POREXTHERM WDS), and includes fumed silica (SiO ₂ , 80 parts), silicon carbide SiC, 15 parts), and others (ceramic fibers, etc., 5 parts). It is an insulation board obtained by compression (press) molding a mixture of
Next, as shown in FIG. 11(b), the SiC-added silica airgel powder 10 filled in the double-shell steel container 11 was placed on the upper surface of the high-performance heat insulating material 9 laid on the bottom surface of the outer-frame steel container 18. 9 mm was laid (Fig. 32(a)). After that, as shown in FIG. 11(c), the double shell steel container 11 is inserted into the outer frame steel container 18 (FIG. 32(a)). As shown in FIG. 11(d), the SiC-added silica airgel powder 10 filled in the double-shell steel container 11 was poured from the opening of the space (1.9 mm) on the side of the container 11, and the result was shown in FIG. 11 ( As shown in e), it was filled up to a position -10 mm from the top of the side surface (arrow in FIG. 32(b)).

(4) Measures to prevent overflow of insulation (high-performance insulation and SiC-added silica airgel powder) between the double-shell steel container and the outer frame steel container Even if the insulation box overturns, the double-shell steel container 12(a), (b) and 12(a), (b) and As shown in FIGS. 33(a) and 33(b), the insulating paint board 6 prepared by coating the insulating paint 13 to a thickness of 10 mm was filled without gaps (FIG. 33(b)). By filling without gaps, in the extreme cold (-196 ° C) test, the temperature of the space between the double-shell steel container 11 and the outer frame steel container 18 is also cooled over time by liquefied nitrogen, and the internal pressure is in a decompressed state, and as shown in FIG. 28, a reduction in thermal conductivity of the SiC-added silica airgel powder 10 can be expected.

In other words, the performance required for the heat insulating paint board 6 is that when the outer frame steel container receives heat, it has heat insulation performance against both low and high temperatures, and the ability to keep the gap closed and contraction due to the expansion of the outer frame steel container. The best performance is to have moderate elasticity (restoration), such as not breaking against.
Therefore, the evaluation results of the heat insulating paint board 6 are shown in Table 1 below.

From Table 1, in hardness measurement, inorganic materials other than the above-mentioned heat insulating paint are difficult to measure because the shape is granular or fibrous, and the hardness of the heat insulating material as a whole is measured. Therefore, it is not suitable for satisfying the above performance requirements. In other words, granules and fibrous materials are not suitable for the overflow prevention function of the insulating material between the double-shell steel container and the outer-frame steel container when the container is overturned.
Also, foam glass is brittle and is also unsuitable for fulfilling the above functions.
Furthermore, organic materials are difficult to apply to heat insulation in a high temperature environment (for example, 500°C). In the hardness measurement in Table 1, in rigid urethane foam to polystyrene foam, the explanation that there was a dent after measurement indicates that the hardness meter was embedded and did not restore.
Therefore, the heat insulating paint board formed with the heat insulating paint in Table 1 has a temperature range θ of -200°C to 600°C, a thermal conductivity of 0.032 (W/mK), and a measured hardness of 65. It has the above-mentioned overflow prevention function in the extremely low temperature range and the extremely high temperature range compared to other materials.
However, the hardness was measured using an Asker rubber hardness tester C type manufactured by Kobunshi Keiki Co., Ltd. For reference, this durometer gives a value of about 10 for human skin and about 80 for car tires.

The heat insulating paint 13 for molding the heat insulating paint board 6 is a silicate (manufactured by ZRC Japan Co., Ltd., trade name: zero VOC water-based normal temperature zinc plating ZRC-liquid) as a binder (in the above-mentioned part, 5 parts by mass of alkali-resistant glass fiber (manufactured by Nippon Electric Glass Co., Ltd., product name: ACS6H-103 (20) / V, φ 13 μm x 6 mm length) for 100 parts by mass (referred to as a special inorganic resin) was added and mixed with stirring, 10 parts by mass of porous silica airgel powder (manufactured by Cabot Corporation, trade name: P200, average particle size: 0.01 to 1.2 mm) was added and mixed with stirring.

1.3 Top Lid (1) Vacuum Glass As shown in FIGS. 22, 24, 29 and 30, the top lid 16 has a third spacer between two sheets of glass so that the inside of the heat insulating box can be observed from above. The vacuum glass 2 is used in which the airtight space formed by interposing is formed in the second reduced-pressure airtight layer 25 which is substantially vacuumed by reducing the pressure. As the vacuum glass 2, "Spacia" manufactured by Nippon Sheet Glass Co., Ltd. was used, and as shown in FIG. As shown in FIG. 13, in order to fix the vacuum glass, it was fixed to high-density rigid urethane foam 3 (nominal density: 300 kg/m ³ ) as a fixing substrate using a urethane-based adhesive. In order to eliminate gaps at both ends in the longitudinal direction, rigid urethane foam 5 (nominal density: 45 kg/m ³ ) was used and fixed with a urethane adhesive as shown in FIG.
As shown in FIGS. 22, 24, and 30, a rubber sponge 4 (manufactured by Softprene Kogyo Co., Ltd., product name: OP180, width 20 mm, thickness) is applied as a cushioning material to the lower surface of the upper lid 16 in contact with the main portion 17 of the heat insulation box. 4.6 mm with single-sided adhesive tape) was attached.

(2) Attachment of buckles As shown in Figs. A total of eight buckles 7 were fixed with a urethane-based adhesive.

(3) Heat-shielding paint In the long-time program, the near-infrared rays emitted from the illumination lights in the temperature-controlled room set at 39.7°C are reflected, and the heat enters the heat-insulating box 20 through the high-density rigid urethane foam 3 and the rigid urethane foam 5. For the purpose of preventing the intrusion of heat shielding paint 1 made of spherical and non-porous silica powder (SiO ₂ ), Adgreen Coat EX-009 (white)) was adopted, and as shown in Figs. The outer surface of Forms 3 and 5 was painted three times at two hour intervals.

[Implementation of various tests (extreme cold, scorching heat, long period)]
2. Extreme cold (-196℃)
(Test overview)
Water of 1° C. is poured into the heat insulating box 20A up to a height of 5 cm from the bottom, and then, as shown in FIGS. It is placed in water so that it rotates upward, and then the insulation box 20A is placed on the bottom of a steel container for liquid nitrogen (LN2) storage tank. In this state, liquid nitrogen (LN2, -196°C) was poured into the steel container for liquid nitrogen (LN2) storage so that the height from the bottom surface was 20 cm, and the outer surface of the heat insulating box 20A was cooled. A timer was started at the same time as the liquid nitrogen was supplied, and the time until the water in the heat insulating box 20A was frozen and the rotating doll stopped was measured. During the test, the liquid nitrogen naturally evaporated and decreased, so the liquid nitrogen was replenished every 5 minutes.

(Test results)
The stopping time of the spinning doll was 51 minutes and 31 seconds.
3. Burning (500°C)
(Test overview)
The heat insulation box 20B was used in the test of the scorching knitting (500°C).
As shown in FIG. 16(a), the lower surface of a steel plate with a thickness of 2 cm is heated with a gas burner, and the heat insulating box 20B is placed on the upper surface of the steel plate whose surface temperature has reached 500° C. Immediately after that, as shown in FIG. ), (c), a doll placed on the base of three icicles of φ1 cm×10 cm is placed on the inner bottom surface of the heat insulating box 20B. As soon as the doll was placed still, a timer was started to measure the time it took for the icicles to melt and the doll to topple over.

(Test results)
It took 19 minutes and 21 seconds for the icicles to melt and the doll to fall.
4. Long knitting (39.7℃)
(Test overview)
In the long knitting (39.7°C) test, the ice generated in the heat insulating box 20A used in the extreme cold knitting (-196°C) was melted with water at 60°C, then the water inside was removed and the temperature was returned to normal temperature. A long-time knitting (39.7°C) test piece was used. As shown in FIG. 17(b), a pre-weighed popsicle stick with a plastic stick was fixed in a heat-insulating box 20A at a central height position. It was allowed to stand for 80 minutes in a constant temperature room adjusted to 39.7°C, which is the maximum temperature in the summer of 2016 in Tajimi City, Gifu Prefecture. After 80 minutes had passed, the popsicles in the heat-insulating box 20A were taken out, the weight of the remaining popsicles was measured, and the amount of popsicles melted in 80 minutes was calculated.

(Test results)
The melted amount of popsicle was less than 1 g.

As described above, reference numerals are used for convenience of comparison with the drawings, but such entries do not limit the present invention to the configurations shown in the attached drawings. Moreover, it is a matter of course that the present invention can be embodied in various modes without departing from the gist of the present invention.

1 Thermal insulation paint 2 Vacuum glass 3 High density rigid urethane foam 4 Rubber sponge 5 Rigid urethane foam 6 Thermal insulation paint board 7 Buckle 8 Steel plate 9 High performance insulation material 10 Silicon carbide added silica airgel powder 11 Double shell steel container (first container)
12 Steel plate 13 Thermal insulation paint 14 Waterproof material 15 Steel plate (thin plate)
16 upper lid (cover)
17 Insulation box main part 18 Outer frame steel container (second container)
20 Insulation box (container body)
23 First reduced-pressure airtight layer 25 Second reduced-pressure airtight layer S Accommodation space

Claims (4)

A container body is provided inside which forms a storage space capable of storing a material to be insulated,
provided with a lid capable of closing the entrance of the container main body through which the material to be insulated can be put in and out of the accommodation space;
The container main body is formed by inserting a first double-shell steel container into a second outer-frame steel container,
The first double-shell steel container has a first pressure-reduced pressure-reduced airtight layer containing a first spacer member between the peripheral walls of the inner steel container inserted into the outer steel container,
A gap space between the first double-shell steel container and the second outer-frame steel container is sealed under atmospheric pressure while containing a second spacer member,
The lid portion is provided with a second reduced-pressure airtight layer that is decompressed with a third spacer member interposed in the thickness thereof,
In the first reduced-pressure airtight layer, as the first spacer member, airgel powder made of silicon dioxide (SiO ₂ ), which is heat-resistant and has high heat-retaining performance against low temperatures, and silicon carbide (SiC), which has high heat-resistant and heat-retaining performance against high temperatures. ) is filled with powder mixed with
Fumed silica (SiO ₂ ) and silicon carbide (SiC) are used as the second spacer member in the gap space between the first double-shell steel container and the second outer-frame steel container. Filling a heat insulating molded plate obtained by compression molding the mixture containing and the mixed powder,
Insulation in which the upper end portion of the gap between the first double-shell steel container and the second outer-frame steel container is filled with an elastic heat-insulating molded body over the entire circumference. container. An opening is provided in the lid, and an airtight space is formed between the plurality of glass plates in a state in which the third spacer member is interposed between the plurality of glass plates arranged side by side so that the state of the interior can be observed. 2. The insulated container according to claim 1, wherein said opening is fitted with vacuum multi-layered glass in which said airtight space is decompressed while the entire periphery is airtightly sealed. placing the heat insulating molded plate against the inner surface of the second outer frame steel container;
3. The insulated container according to claim 1, wherein said mixed powder is filled in a space between said insulated molded plate and the side surface of said first double-shell steel container. For forming the first double-shell steel container according to any one of claims 1 to 3,
Filling the gap between the inner steel container and the outer steel container with the first spacer member made of the mixed powder having heat resistance and heat insulation,
The powder-filled space between the inner steel container and the outer steel container is heated before the powder-filled space between the inner steel container and the outer steel container reaches normal temperature by heating the first double-shell steel container in a dryer. A method for producing an insulated container in which the first pressure-reduced airtight layer is formed by sealing in an airtight state.

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