JPH07293782A - Heat insulating element - Google Patents

Abstract

PURPOSE:To improve durability against repetitive heating, in a heat insulating element such as a vacuum heat insulating container, by reducing stress which is generated at a jointing member such as a membrane based on thermal expansion without an increase in the number of processing. CONSTITUTION:A vacuum heat insulating layer 16 is formed between an inner container 13 and an outer container 14 jointed with each other through a membrane 15. The outer container 13 is formed out of a material whose coefficient of linear expansion is higher and whose Young's modulus is lower than the inner container 14.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat insulating body such as a vacuum heat insulating container.

[0002]

2. Description of the Related Art In a vacuum heat insulating container having a vacuum heat insulating layer formed between an outer container and an inner container, when a high-temperature item is stored in the container, the inner container is heated by the heat. Expands.

FIG. 5 shows a sectional structure of a main part of a vacuum heat insulating container 2 having an opening 1 at one end. The vacuum heat insulating container 2 has a double wall structure having an outer container 3 and an inner container 4, and in the opening 1, the end edges of the inner and outer containers 3 and 4 are connected to each other by a membrane 5. ing. A vacuum heat insulating layer 6 is formed between the outer container 3 and the inner container 4.
The outer container 3 and the inner container 4 are made of the same material, and therefore their linear expansion coefficient and Young's modulus are set to be equal to each other.

In such a vacuum heat insulating container 2, when the inner container 4 is heated as described above, the inner container 4 thermally expands more than the outer container 3 and its end portion is expanded as shown in FIG. Protrude to the opening 1 side. δ indicates the amount of protrusion.
As a result, there is a risk that excessive thermal stress acts on the membrane 5 to cause damage.

In order to deal with this, conventionally, as shown in FIG. 7, the membrane 5 is constructed in multiple layers for stress relaxation, or as shown in FIG. 8, the inner container 4 absorbs thermal expansion. Measures are taken such as forming the bent portion 7 or using both as shown in FIG.

[0006]

However, if the membrane 5 is formed in multiple layers or the bent portion 7 is formed in the inner container 4 as described above, the number of processing steps is increased when the container 2 is manufactured, and the cost is increased. There is a problem that it is bulky.

Therefore, the present invention solves such a problem and reduces the stress generated in the connecting member such as the membrane due to the thermal expansion without increasing the number of processing steps and improves the durability against repeated heating. The purpose is to

[0008]

In order to achieve this object, the present invention provides a heat insulating body in which a heat insulating layer is formed between a pair of wall bodies connected to each other via a connecting member. It is made of a material having a larger linear expansion coefficient and a smaller Young's modulus than the other wall body.

According to a preferred embodiment of the present invention, the pair of walls is composed of an outer container and an inner container, and a vacuum heat insulating layer is formed between the outer container and the inner container to form a vacuum heat insulating container. The outer container is formed of a material having a larger linear expansion coefficient and a smaller Young's modulus than the inner container.

[0010]

According to this structure, when the other wall body thermally expands due to a temperature rise such as heating, the temperature of the one wall body also rises to some extent in correspondence with this, and the temperature of the one wall body increases. Also undergoes thermal expansion. However, since the one wall body is made of a material having a larger linear expansion coefficient than the other wall body, the one wall body thermally expands at a rate higher than that when the same material is used. Also, since one wall has a smaller Young's modulus than the other wall, when the tensile force transmitted through the connecting member along with the extension of the other wall is applied, it is larger than that when the same material is used. Deform in proportion. For this reason,
The difference in the amount of deformation between one wall body and the other wall body becomes small.
This reduces the stress generated in the connecting member, that is, the membrane, and improves the durability against repeated heating. Further, since it suffices to appropriately select the materials for the one wall body and the other wall body, and no special processing or the like is required, the number of processing steps does not increase.

Specifically, when a vacuum heat insulating container is formed by forming a vacuum heat insulating layer between the outer container and the inner container, the outer container has a larger linear expansion coefficient than the inner container. Moreover, it may be formed of a material having a small Young's modulus.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a heat insulating body according to one embodiment of the present invention. The heat insulator is composed of a vacuum heat insulating container 12 having an opening 11 at one end, and the vacuum heat insulating container 12 has an outer container 13 and an inner container 14. The outer container 13 at the opening 11
The edges of the inner container 14 and the inner container 14 are connected to each other by a membrane 15. A vacuum heat insulating layer 16 is formed between the outer container 13 and the inner container 14. An opening / closing heat insulating lid (not shown) is attached to the opening 11.

The outer container 13 is made of a material having a larger linear expansion coefficient and a smaller Young's modulus than the inner container 14. That is, when the linear expansion coefficients of the outer container 13 and the inner container 14 are α1 and α2, respectively, and the Young's modulus is E1 and E2, respectively, α1> α2 and E1 <E2.

In such a structure, for example, by storing high-temperature items inside the vacuum heat insulating container 12, the inner container 14
When the inside of the container is heated, the temperature of the outer surface of the vacuum heat insulating container 12, that is, the outer container 13 also rises accordingly. Therefore, in addition to the inner container 14 thermally expanding due to the heating inside, the outer container 13 also thermally expanding to some extent. At this time,
Since the outer container 13 is made of a material having a larger linear expansion coefficient than the inner container 14, the outer container 13 thermally expands at a rate higher than that of the inner container 14.

When the inner container 14 is thermally expanded, a tensile force is transmitted to the outer container 13 through the membrane 15 accordingly. However, since the outer container 13 has a smaller Young's modulus than the inner container 14, when it receives this tensile force, it deforms at a rate larger than that of the inner container 14.

Therefore, the difference between the deformation amounts of the inner container 14 and the outer container 13 becomes small, and the protrusion amount δ ′ of the inner container 14 shown in FIG. 2 is larger than the conventional protrusion amount δ shown in FIG. Becomes smaller. For this reason, the stress generated in the membrane 15 becomes small, and even if heating and cooling are repeated, the repeated life thereof becomes long.

Explaining a concrete example, for example, a stainless steel material (JI
S SUS304 material, Young's modulus E2 = 195 × 10 ³ M
Pa, linear expansion coefficient α2 = 16.4 × 10 ⁻⁶ )
A 1.5 mm thick aluminum material (Young's modulus E1 = 70 × 10 ³ MPa, coefficient of linear expansion α1 = 23 × 1)
Using the 0 ^-6), 800 mm and 1000 mm · height width
-In the vacuum heat insulating container 12 in which the depth is 1500 mm and the vacuum heat insulating layer 16 is formed by filling fibers so that the heat insulating thickness is 30 mm, when the inside of the container is heated to 300 ° C, the temperature of the outer surface becomes room temperature. It rises by about 10 ° C. In this case, according to the result of the finite element analysis, compared with the conventional case where both the inner and outer containers use the SUS304 material, the outer container 13
The amount of protrusion δ ′ of the inner container 14 relative to the inner container 14 can be reduced by 0.4 mm. As a result, the magnitude of the stress acting on the membrane 15 becomes 3/4, and the repeated life obtained from the design fatigue curve can be doubled.

When joining the SUS304 material and the aluminum material in this way, it is appropriate to use a clad material in the joining portion as shown in FIGS. 3 and 4. That is, in these figures, 21 is SUS304 material, 22
Is an aluminum material, and 23 is a clad material.

Materials suitable for forming the outer container 13 and the inner container 14 are, for example, as follows. That is, when using aluminum or an aluminum alloy for the outer container 13, or when using copper or a copper alloy for this, use carbon steel, stainless steel, Invar, Elinvar, etc. for the inner container 13. You can As the stainless steel, austenitic or ferritic stainless steel can be used. When austenitic stainless steel is used for the outer container 13, carbon steel or ferritic stainless steel is suitable for the inner container 14.

As a means for further prolonging the life of the vacuum heat insulating container 12, in addition to changing the materials of the outer container 13 and the inner container 14 as described above, the configurations shown in FIGS. You can also

In the above embodiment, the case where the inside of the vacuum heat insulating container 12 is heated by storing the high temperature item has been described, but the present invention is similarly applied to the case where the inside of the vacuum heat insulating container 12 is cooled by storing the low temperature item. You can Also a vacuum insulation container
The present invention can be applied to not only 12 but also general heat insulating containers. Further, the present invention can be applied to, for example, a panel-shaped heat insulator other than the container-shaped heat insulator.

[0022]

As described above, according to the present invention, one wall body of a heat insulating body in which a heat insulating layer is formed between a pair of wall bodies connected to each other via a connecting member is more preferable than the other wall body. Since it is made of a material having a large linear expansion coefficient and a small Young's modulus, when the other wall body is heated and thermally expanded, the amount of protrusion of the other wall body relative to the other wall body should be reduced. Therefore, the stress generated in the connecting member can be reduced without increasing the number of processing steps,
Therefore, durability against repeated heating can be improved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view of a vacuum heat insulating container as a heat insulating body according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing a state where a main part in FIG. 1 thermally expands.

FIG. 3 is a detailed view showing an example of a joint portion between the outer container and the inner container in FIG.

FIG. 4 is a detailed view showing another example of the joint portion between the outer container and the inner container in FIG.

FIG. 5 is a schematic cross-sectional view of a main part of a conventional vacuum heat insulating container.

FIG. 6 is a diagram showing a state where the portion shown in FIG. 5 is thermally expanded.

FIG. 7 is a diagram showing a configuration example for reducing stress generated in a membrane of a conventional vacuum heat insulating container.

FIG. 8 is a diagram showing another configuration example for reducing the stress generated in the membrane of the conventional vacuum heat insulating container.

FIG. 9 is a diagram showing still another configuration example for reducing the stress generated in the membrane of the conventional vacuum heat insulating container.

[Explanation of symbols]

 13 Outer container 14 Inner container 15 Membrane 16 Vacuum insulation layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Morimoto Makoto 2-26 Ohama-cho Amagasaki City Hyogo Prefecture Kubota Mukogawa Works

Claims (3)

[Claims] 1. A heat insulator in which a heat insulating layer is formed between a pair of wall bodies connected to each other via a connecting member, wherein one wall body has a larger linear expansion coefficient than the other wall body. A heat insulator characterized by being formed of a material having a small Young's modulus. 2. A pair of walls is composed of an outer container and an inner container, a vacuum heat insulating layer is formed between the outer container and the inner container to form a vacuum heat insulating container, and the outer container is the inner container. The heat insulator according to claim 1, wherein the heat insulator is made of a material having a larger linear expansion coefficient and a smaller Young's modulus. 3. A vacuum heat insulating container constituted by an outer container and an inner container is open at one end, and a connecting member connects the end edge portion of the outer container and the end edge portion of the inner container at the opening. 3. The membrane according to claim 2, wherein
Insulated body described.