JPS633740B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat insulating structure, and more particularly to a heat insulating structure having a foamed member as a component, which is intended to improve heat insulating properties. First, a conventional heat insulating structure having a foamed member as a component, which is often used for heat or cold insulation, will be described. FIG. 1 is a perspective sectional view showing an example of a conventional heat insulating structure using urethane foam. The heat insulating structure shown in FIG. 1 is used, for example, in an electric refrigerator, and the heat insulating structure 1 includes a steel plate 2 for a heat insulating wall and a urethane foam 3 for a foam member, which are disposed on the outside of the refrigerator. It is a composite integrated heat insulating structure made of members such as , plastic sheet 4, etc. This heat insulating structure 1 takes advantage of the low thermal conductivity of the urethane foam 3, and is the best at present. However, the density of the urethane foam and The thermal conductivity of the Freon gas itself contained in urethane foam has reached its limit, and if the density is reduced below this, the strength will decrease and the bubbles will become continuous, so it is difficult to expect a significant improvement in the insulation properties. Can not. Further, in order to solve the current problems, the development of vacuum insulation technology is progressing. FIG. 2 is a perspective view showing a conventional vacuum bag-like body used for vacuum insulation. In FIG. 2, reference numeral 5 denotes a vacuum bag-like body whose interior is evacuated 6, and this vacuum bag-like body 5 is used in place of the above-described heat insulating structure 1 at a desired location. However, in order to obtain the vacuum bag-like body 5 shown in FIG. 2, it is necessary to have strength that can withstand internal decompression and maintain its shape, but it is difficult to manufacture a vacuum bag-like body that is lightweight and satisfies these requirements. was difficult. The present invention eliminates the above-mentioned drawbacks of the prior art,
The object of the present invention is to provide a heat insulating structure having improved heat insulating properties and having a foamed member as a component. The heat insulating structure of the present invention is characterized by having a tubular body with a vacuum inside, that is, a vacuum tubular body in the heat insulating structure having a foam member with low thermal conductivity as a component.
The heat insulating structure is located inside the foam member. More specifically, we focused on the fact that the tubular shape is the shape that can withstand the most internal and external pressure, and created a heat insulating structure that achieves high heat insulation properties by integrating the vacuum tubular body and the foam heat insulating material. be. The present invention will be explained below with reference to Examples. FIG. 3 is a perspective sectional view of a heat insulating structure according to an embodiment of the present invention, and FIG. 4 is a front view of the evacuated tubular body in FIG. 3. In FIG. 3, parts with the same numbers as in FIG. 1 are the same parts. 7 is a straight tubular body with a vacuum inside, which is arranged in a line inside the urethane foam 3 in parallel with the steel plate 2 related to the heat insulating wall of the heat insulating structure 1A; 8 is a vacuum tubular body; , is a sealing part that seals the vacuum at the end when manufacturing the vacuum tubular body 7. The material of the vacuum tubular body 7 is glass.
The glass vacuum tubular body 7 is easy to manufacture because the technology for manufacturing conventional electronic vacuum tubes, lighting equipment, etc. can be applied as is, and it also has the advantage of being able to maintain a high degree of vacuum over a long period of time. It also has relatively low thermal conductivity and is inexpensive. The shape of the vacuum tubular body 7 is as shown in FIG.
It is a straight pipe that is easy to manufacture, the wall thickness is 1mm, and the outside diameter is 20mm.
mmφ. The outer diameter of the tube is suitably 10 mmφ to 30 mmφ; if it is less than 10 mmφ, the specific weight of the evacuated tubular body 7 will increase, and if it is more than 30 mmφ, the thickness of the heat insulating structure 1A will increase, which is not a good idea. The degree of vacuum inside the vacuum tubular body 7 was set to 10 ⁻⁴ Torr. Note that when the degree of vacuum is 10 ^-2 Torr, the thermal conductivity is approximately 1/10 that of air, but preferably 10 ^-4 Torr.
is desirable. Next, the vacuum tubular body 7 obtained in this manner
were arranged in a row parallel to the steel plate 2, and a urethane foam 3, which is a foamed member with a low thermal conductivity, was formed surrounding the steel plate 2. The table shows the thermal conductivity of various materials along with their densities. Also shown is xenon gas (Xe), which has the lowest thermal conductivity among real gases.

[Table] As can be seen from the table, urethane foam, styrene foam, etc. are typical foam members, and in this example, urethane foam was used because it can provide the strength and high heat insulation of the heat insulating structure 1A. Moreover, when the foamed urethane 3 is foamed together with other members, it easily adheres to the other member, the vacuum tubular body 7 in this embodiment, and is characterized in that it has excellent shear strength and bending strength. The heat insulating structure 1A of this example configured in this way
In this case, the heat flow from the steel plate 2 side is in the part where the vacuum tubular body 7 is disposed, and flows from the urethane foam 3 → the glass of the vacuum tubular body 7 → the vacuum part of the vacuum tubular body 7 →
Since the process passes from the glass of the vacuum tubular body 7 to the urethane foam 3, the heat insulation properties are improved by 20 to 40% compared to a conventional heat insulating structure using only the urethane foam as a heat insulating member. Although glass was used as the material for the vacuum tubular body 7 in this embodiment, plastic or metal (for example, aluminum) may be used instead of glass. Plastic has the advantage of having lower thermal conductivity than glass and being lighter. When using metal, if the wall thickness of the evacuated tubular body is 1 mm or less, it will have little effect on the insulation properties of the overall insulation structure, and it will be almost equivalent to using a glass evacuated tubular body. Provides insulation properties. Furthermore, on the inner wall, outer wall, or both walls of the vacuum tubular body made of glass or plastic,
Forming a thin film of metal (for example, aluminum) increases the radiation rate and further improves the heat insulation properties. FIG. 5 is a front view showing various examples of the vacuum tubular body according to the present invention. In addition to the straight vacuum tubular body 7 shown in FIG. 4, the shape of the vacuum tubular body may be a circular vacuum tubular body 7A (8A is a sealing part,
The same applies hereafter), the U-shaped vacuum tubular body 7B in FIG.
The square-shaped vacuum tubular body 7C shown in FIG. 5, the L-shaped vacuum tubular body 7D shown in FIG. 5, and the like are used. FIG. 6 is a sectional view of a heat insulating structure according to another embodiment of the present invention. In FIG. 6, the same parts as those in FIG. 3 are denoted by the same numbers. In this example,
The evacuated tubular bodies 7 are arranged in two rows in parallel with the steel plates 2 that form the heat insulating walls of the heat insulating structure 1B. Thus, by arranging the vacuum tubular bodies 7 in two rows, the heat insulation properties are further improved than when arranging them in one row. However, if they are arranged in two or more rows or in a plurality of rows, the apparent specific gravity of the heat insulating structure becomes large, so the use of such a heat insulating structure may be limited. FIG. 7 is a perspective view of a heat insulating structure according to still another embodiment of the present invention. In FIG. 7, the same parts as those in FIG. 3 are denoted by the same numbers. And 9 is a hard skin layer formed on the outer surface of the heat insulating structure 1C. This skin layer 9 is formed by a conventional molding method for forming a skin layer. In this embodiment, the urethane foam 3 and the skin layer 9 are made of the same material and are molded together with the vacuum tubular body 7, so the steel plates and plastic sheets that were conventionally placed on both sides of the urethane foam are replaced. This is no longer necessary, and the number of manufacturing steps can be reduced. The heat insulating structures described in each of the above examples have 20 to 40% better heat insulating properties and 10% higher shear strength, bending strength, etc., than conventional ones that use only foamed urethane as a heat insulating member. There is also the effect of further improvement. Furthermore, by arranging the evacuated tubular bodies in a focused manner according to the desired heat insulation performance, a heat insulation structure with excellent cost performance can be obtained. As explained in detail above, according to the present invention, a heat insulating structure is constructed by disposing a vacuum tubular body having a vacuum inside a foamed member, so that the following effects can be obtained. ○B Since the tubular body has a shape that can best resist internal depressurization, the vacuum tubular body has a high degree of vacuum that cannot be obtained with a bag-like body (for example,
10 ^-4 Torr), and its thermal conductivity is extremely low. ○B Since the inside of the vacuum tubular body is under high vacuum,
There is no need to encapsulate an absorbent substance for adsorbing gas inside it. ○C Since the vacuum tubular body has a circular cross-sectional shape, it is easy to manufacture and inexpensive. For example, a glass evacuated tubular body can be easily manufactured by directly applying the technology for conventional electronic vacuum tubes, lighting equipment, and the like. ○D The above-mentioned heat insulating structure can prevent heat transfer by using the vacuum tubular body and the foam member, so it is of course better than a cold insulation wall filled with a conventional cold insulation material (for example, carbonized cork). thing,
The insulation properties are improved by 20 to 40% compared to an insulation structure made only of foam members. ○E Since the heat insulating structure is made by firmly adhering the foam member and the vacuum tubular body, the vacuum tubular body acts as a strength member, increasing the rigidity of the heat insulating structure, and increasing the shear strength and bending strength. will improve. (F) The heat insulating structure in which a vacuum tubular body is disposed inside a foamed member is extremely easy to manufacture because the vacuum tubular body can be inserted and integrally formed with a foam material.

[Brief explanation of the drawing]

FIG. 1 is a perspective cross-sectional view showing an example of a conventional heat insulating structure using foamed urethane, FIG. 2 is a perspective view showing a conventional vacuum bag-like body used for vacuum insulation, and FIG. The figure is a perspective sectional view of a heat insulating structure according to an embodiment of the present invention, FIG. 4 is a front view of the evacuated tubular body in FIG. 3, and FIG. FIG. 6 is a front view showing an example, FIG. 6 is a cross-sectional view of a heat-insulating structure according to another embodiment of the present invention, and FIG. 7 is a perspective cross-sectional view of a heat-insulating structure according to still another embodiment of the present invention. be. 1A, 1B, 1C...insulating structure, 2...steel plate, 3
...Urethane foam, 7, 7A, 7B, 7C, 7D...
Vacuum tubular body, 9...epidermal layer.

Claims (1)

[Scope of Claims] 1. A heat insulating structure comprising a foamed member with low thermal conductivity as a component, characterized in that a tubular body having a vacuum inside, that is, a vacuum tubular body is disposed inside the foamed member. Insulated structure. 2. The heat insulating structure according to claim 1, wherein the vacuum tubular body is made of glass or plastic. 3. The heat insulating structure according to claim 2, wherein a thin metal film is formed on the inner wall or outer wall of a vacuum tubular body. 4. The heat insulating structure according to claim 1, wherein the vacuum tubular body is formed into a straight tube, circular tube, U-shaped tube, R-shaped tube, or L-shaped tube. 5. The heat insulating structure according to claim 1, wherein a hard skin layer is formed on the outer surface of the foam member. 6. The heat insulating structure according to claim 1, wherein the vacuum tubular bodies are arranged in one or more rows parallel to the heat insulating wall of the heat insulating structure.