JPH08173331A - Vacuum insulation layer - Google Patents

Abstract

PURPOSE: To provide a vacuum thermal insulting layer, and a vacuum thermal insulating case and vacuum thermal insulating piping using the vacuum thermal insulating layers which can keep a certain level of vacuum when they are used at relatively high temperature by installing several kinds of getter materials of different characteristics. CONSTITUTION: A vacuum thermal insulating layer 14 is formed between the inner wall 12 and outer wall 13 of the vacuum thermal insulating case 11, and a radiation preventive material 15 is attached inside the vacuum insulating layer 14. Three different kinds of getter materials A, B and C with different temperature sensitivity are fixed to the inner wall 12, the outer wall 13, and the radiation preventive material 15, respectively. The most suitable getter material is selected from among A, B, and C each with specified property based on the temperature inside the case 16 when the case is used and according to the kinds of gases emitted from these materials. In this way, efficiency in catching gases emitted from the materials of the vacuum thermal insulating case 11 will be improved and the vacuum deterioration inside the layer 14 can be prevented in the wide temperature range, so that the temperature range for using the vacuum thermal insulating case 11 can be expanded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum heat insulating layer, and more particularly, to a vacuum heat insulating layer provided with a getter material for trapping released gas generated in the vacuum heat insulating layer to maintain the degree of vacuum in the layer. The present invention also relates to a vacuum heat insulating container and a vacuum heat insulating pipe having the vacuum heat insulating layer.

[0002]

2. Description of the Related Art As shown in FIG. 4, conventionally, in a vacuum heat insulating container 1 such as a thermos bottle, a gas released from a material during a vacuum high temperature baking step during manufacturing or during use is discharged between an inner wall 2 and an outer wall 3. The activated getter material 5 provided in the vacuum heat insulating layer 4 formed in the above is used to capture and to maintain and improve the degree of vacuum of the vacuum heat insulating layer 4. In FIG. 4, reference numeral 6 is a vacuum sealing portion such as vacuum brazing.

Such a conventional vacuum heat insulating container 1 such as a thermos has a temperature range of the inside 7 of the container during use from a low temperature liquefied gas temperature to about 100 ° C. Since the amount of released gas was used in a small amount, it was easy to maintain the vacuum degree of the vacuum heat insulating layer 4.

[0004]

On the other hand, in recent years, in connection with energy saving, environmental problems, etc., there has been a demand for a vacuum heat insulating container and a vacuum heat insulating pipe used in the medium to high temperature field of 300 to 900 ° C. However, in such a medium and high temperature state,
Due to the large amount of gas released from the materials that make up the container and piping, the same idea as in the low temperature field below 100 ° C
It was difficult to maintain the vacuum degree of the vacuum heat insulating layer.

Therefore, the present invention relates to a vacuum heat insulating layer for forming a vacuum heat insulating container or a vacuum heat insulating pipe, which can maintain a predetermined degree of vacuum for a long time even when it is used at medium and high temperatures, and the vacuum heat insulating layer. An object of the present invention is to provide a vacuum heat insulating container and a vacuum heat insulating pipe.

[0006]

In order to achieve the above object, the vacuum heat insulating layer of the present invention is characterized in that a plurality of types of getter materials having different characteristics are provided, and a plurality of getter materials having different characteristics are provided. The types of getter materials are characterized by being getter materials having different characteristics such as operating temperature, operating speed, and sorption gas type. Further, the vacuum heat insulating container and the vacuum heat insulating pipe of the present invention are characterized by having the above vacuum heat insulating layer.

[0007]

[Operation] As described above, the operating temperature,
By providing a plurality of types of getter materials having different characteristics such as operating speed and sorption gas type, the degree of vacuum can be stably maintained over a wide temperature range and for a long period of time.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in more detail below with reference to the embodiments shown in the drawings. FIG. 1 shows an embodiment of the present invention, and schematically shows the structure of a vacuum heat insulating container or a vacuum heat insulating pipe having a vacuum heat insulating layer of the present invention (hereinafter, a vacuum heat insulating container including the vacuum heat insulating pipe). It is shown.

The vacuum heat insulating container 11 has a structure in which a radiation preventing material (shield material) 15 is arranged in a vacuum heat insulating layer 14 formed by an inner wall 12 and an outer wall 13, and the inner wall 12 and the outer wall 13 are provided. , Three types of getter materials A, B, and C having different operating temperature characteristics are attached to the shield material 15.

The getter materials A, B, and C are selected to have appropriate characteristics according to the temperature conditions inside the container 16 when the container is used, the type of gas released from the material, and the like. For example, when the outer surface of the inner wall 12 and the inner surface of the outer wall 13 are silver-plated, and 30 layers of stainless steel mylar are wound as a radiation barrier on the outer side of the inner wall 12 (in the vacuum heat insulating layer), the temperature inside the container 16 is increased. Assuming that the emissivity of the stainless steel mylar is similar to that of a nickel polished surface, the surface temperature of the barrier of the 30th layer is calculated to be about 220 ° C. The temperature distribution inside is schematically shown in FIG.

At this time, the temperature is about the same as that of the inside 16 of the container.
As the getter material A attached to the inner wall 12 at a temperature of 00 to 900 ° C., Zr / Al suitable for gas sorption in a high temperature range,
As a getter material B for attaching a getter material such as Zr / V / Fe or Zr / Al / Ti system to the shield plate 15 having a temperature of 100 to 400 ° C., Zr / V suitable for gas sorption in a medium temperature range As a getter material C for attaching a getter material such as / Fe or Zr / graphite to the outer wall 13 whose temperature is in the range of room temperature to 100 ° C., a general getter material used in a conventional thermos bottle, for example, La is used. / Ni /
The getter material made of a ternary alloy of Cr may be selected respectively.

Further, it is known that the absorption amount and the sorption speed can be increased by using the above ternary alloy composed of Zr / V / Fe and the getter in which Ti is further arranged, by selecting their respective mixing ratios. Has been. By selecting and combining a plurality of getter alloys having various mixing ratios and using them as the getter materials A, B, and C, not only can the operating temperature range be widened, but the operating speed range can be widened. It is possible to increase the sorption amount according to the number of sorption gas species.

As described above, the gas released from the constituent material of the vacuum heat insulating container 11 is selected by selecting the getter material according to the temperature range during use and the type of gas released in the temperature range and attaching an appropriate amount. Since it is possible to improve the capture efficiency of the vacuum insulation layer and prevent the vacuum deterioration in the vacuum insulation layer 14 in a wide temperature range, it is possible to widen the operating temperature range of the vacuum insulation container 11 and use the vacuum insulation container 11 in the middle and high temperature range. Even if
The degree of vacuum in the vacuum heat insulating layer 14 can be maintained for a long period of time.

The activation of each getter material is carried out by heating the getter material A during use, heating the getter material C from the outer surface of the outer wall 13, and heating the getter material B during use or from the outer surface of the outer wall 13. Can be carried out by any of the above heating methods.

In the vacuum heat insulation pipe, when a laminated heat insulating material such as stainless steel foil or aluminum mylar is used as a radiation preventing material between the inner wall (inner tube) and the outer wall (outer tube), a getter material for the middle temperature range. B may be attached to the intermediate portion of the laminated heat insulating material. At this time, the getter material B is preferably supported by an appropriate supporting member protruding from the inner circumference of the outer tube.

FIG. 3 shows another embodiment of the present invention. A vacuum heat insulating container 21 in which two types of getter materials A and C are attached in a vacuum heat insulating layer 24 formed by an inner wall 22 and an outer wall 23. It is a schematic diagram which shows.

In the present embodiment, the getter material A that operates in the high temperature range is attached to the inner wall 22 that has a medium to high temperature during use, and the low temperature range is used on the outer wall 23 where the temperature during use is room temperature to 100 ° C. The getter material C that operates at is attached.

The getter material A, which operates in the above-mentioned high temperature range, has the same activation temperature as that of the container when the container is in use, and is maintained at the same temperature as that of the use temperature. The capability of capturing the released gas from the material by the heat cycle during the period is maintained, and the vacuum degree in the vacuum heat insulating layer 24 is maintained. Further, the life of the getter material generally tends to be shorter as the operating temperature is higher. Therefore, as shown in the present embodiment, the getter material A that performs gas sorption in the medium and high temperature range when the container is used,
By using the getter material C with a low operating temperature together,
Compared with the case where only the getter material A is used, the vacuum heat insulating layer 2
The degree of vacuum in 4 can be maintained for a long time.

As shown by the broken line in FIG. 3, the inner wall 22
By providing an enlarged overhanging portion 27 that projects toward the inside 26 of the container, and by incorporating a large amount of getter material A in the enlarged overhanging portion 27, it is possible to extend the service life of maintaining the degree of vacuum.

The vacuum sealing structure of the vacuum heat insulating layer is shown in FIG.
The vacuum sealing structure 17 by the vacuum brazing shown in FIG. 3 or the vacuum sealing structure 29 by the valve 28 shown in FIG. 3 may be used, and the shape of the container is not particularly limited.

[0021]

As described above, since the vacuum heat insulating layer of the present invention uses a plurality of types of getter materials having different characteristics such as operating temperature, operating speed, and sorbed gas species, trapping of released gas is achieved. Can be efficiently performed in a wide temperature range for a long period of time, and is particularly suitable as a vacuum heat insulating layer of a vacuum heat insulating container or a vacuum heat insulating pipe used in a medium to high temperature range.

[Brief description of drawings]

FIG. 1 is a schematic view of a vacuum heat insulating container showing an embodiment of the present invention.

FIG. 2 is a diagram showing an example of temperature distribution of a vacuum heat insulating layer.

FIG. 3 is a schematic view of a vacuum heat insulating container showing another embodiment of the present invention.

FIG. 4 is a schematic view showing an example of a conventional vacuum heat insulating container.

[Explanation of symbols]

11, 21 ... Vacuum heat insulation container, 12, 22 ... Inner wall, 13,
23 ... Outer wall, 14, 24 ... Vacuum heat insulation layer, 15 ... Shield material, A, B, C ... Getter material

Claims (6)

[Claims] 1. A vacuum heat insulating layer comprising a plurality of types of getter materials having different characteristics. 2. The vacuum heat insulating layer according to claim 1, wherein the plurality of types of getter materials are getter materials having different operating temperatures. 3. The vacuum heat insulating layer according to claim 1, wherein the plurality of types of getter materials are getter materials having different operating speeds. 4. The getter material of the plurality of types is a getter material having different sorbed gas species.
The vacuum insulation layer described. 5. A vacuum heat insulating container comprising the vacuum heat insulating layer according to claim 1. 6. A vacuum heat insulation pipe having the vacuum heat insulation layer according to claim 1.