JPH09119588A - Vacuum seal structure of vacuum-insulated body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain a sure vacuum sealed state even with the generation of slow leak to a first vacuum seal part by providing the first vacuum seal part for vacuum-sealing an exhaust port of a vacuum-insulated body after vacuum exhaust, and a second vacuum seal part for vacuum-sealing a part outside of the first vacuum seal part. SOLUTION: In a vacuum-insulated body of double structure vacuum- exhausted after filling powder vacuum heat insulating material between an external wall and an internal wall, the inside of a space 2 is vacuum-exhausted to a specified level through an exhaust port 1, and a sealing plug 4 is screwed into an internal thread part 3. At this time, a gasket 11 made of soft metal is firmly inserted between cutting edge parts 8, 10 to aim at vacuum sealing. In this case, a first step part 7 is formed around the exhaust port 1 in an annular member 6, and a second step part 15 is formed around the first step part 7. A flange 17 is then fitted to the annular member 6 by bolts 18 so as to hold the soft metal gasket 20 firmly between the cutting edge parts 16, 19, thus aiming at double vacuum sealing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum sealing structure for a vacuum heat insulator whose inside is double-evacuated.

[0002]

2. Description of the Related Art As a vacuum heat insulator of this type, there is known one having a double structure in which a space between an outer wall and an inner wall is filled with a powder vacuum heat insulating material and then evacuated.
In order to evacuate the space of this double structure, an exhaust port 1 as shown in FIG. 3 is provided in a part of the outer wall, for example. Then, after the space 2 of the double structure is evacuated to a predetermined level through the exhaust port 1, the external screw part 5 of the sealing plug 4 is screwed into the internal screw part 3 formed in the exhaust port 1. . An annular blade 8 is formed on a step 6 around the exhaust 1 in the metal annular member 5 for forming the exhaust 1. The blade 8 and the blade 8 correspond to the blade 8. By tightly sandwiching an annular gasket 11 made of a soft metal with an annular blade portion 10 formed on the head 9 of the sealing plug 4, a vacuum is created between the exhaust port 1 and the sealing plug 4. It will be sealed. Then, the disk 12 that covers the step 7 and the head 9 of the sealing plug 4 at one time is adhered to the end surface of the annular member 6 with an adhesive 13 or the like, thereby protecting the sealing plug 4. .

[0003]

However, in such a conventional configuration, foreign matter may adhere to the surface of the metal gasket 11 during vacuum exhaustion through the exhaust port 1, and therefore, the sealing plug is caused. When the gasket 11 is sandwiched between the blade portions 8 and 10 by screwing in 4, the surface of the gasket 11 may be slightly scratched or foreign matter may be caught as it is. Then, a slow leak occurs from the vacuum sealing portion, and the pressure in the space 2 in the double structure increases due to the slow leak, which makes it impossible to maintain the heat insulating performance of the vacuum heat insulator.

Therefore, an object of the present invention is to solve such a problem and to prevent an increase in pressure inside the double structure even if a slow leak occurs due to a failure in sealing.

[0005]

In order to achieve this object, the present invention provides an exhaust port for evacuating the inside of the double wall by a vacuum sealing structure of a vacuum heat insulating body in which the inside of the double wall is evacuated. A first vacuum sealing part for vacuum sealing after evacuation, and a second vacuum sealing part for vacuum sealing a part outside the first vacuum sealing part in the double wall. It is characterized by having a configuration including and.

According to this structure, even if a slow leak occurs in the first vacuum sealing portion, the reliable vacuum sealing state is maintained due to the existence of the second vacuum sealing portion. At this time,
Since the second vacuum sealing unit seals the outside of the portion vacuum-sealed by the first vacuum sealing unit, stable work is possible and reliable sealing is achieved. .

The volume of the space between the first vacuum seal portion and the second vacuum seal portion can be made significantly smaller than the volume inside the double wall. Therefore, even if a slow leak occurs from this gap into the double wall while the gap is at atmospheric pressure, the pressure increase in the double wall is small, and the required degree of vacuum is maintained. To be done.

By filling the space between the first vacuum sealing portion and the second vacuum sealing portion with a filler, it is possible to further reduce the volume of the void.

[0009]

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, FIG.
Embodiments of the present invention will be described in detail by attaching the same reference numerals to the same members as those shown in FIG.

FIG. 1 shows an embodiment of the present invention. Here, a first step portion 7 is formed around the exhaust port 1 in the annular member 6, and further around the first step portion 7 from the space 2 rather than the first step portion 7. A second step portion 15 that is located apart is formed. An annular blade portion 16 is also formed on the second step portion 15. A conflat flange 17 is attached to the end surface of the annular member 6 with a bolt 18, and an annular blade portion 19 corresponding to the blade portion 16 of the second step portion 15 is formed on the conflat flange 17.

The conflat flange 17 is a bolt.
By being attached to the annular member 6 by 18, an annular gasket 20 made of soft metal is provided between the blade portions 16 and 19.
However, as in the case of the gasket 11, it is strongly sandwiched. Therefore, not only between the sealing plug 4 and the annular member 6,
Vacuum sealing is also performed between the conflat flange 17 and the annular member 6. That is, double vacuum sealing is performed.

When performing such double vacuum sealing,
First, the space 2 is evacuated to a predetermined level by an exhaust device communicating with the exhaust port 1, and then the sealing plug 4 is attached to the exhaust port 1 for primary sealing. Then, when such a primary sealing is completed, the exhaust device is removed, and then the conflat flange 17 is quickly mounted to perform the secondary sealing.

Therefore, even if a slow leak occurs between the sealing plug 4 and the annular member 6, that is, in the portion where the gasket 11 is sandwiched between the blade portion 8 and the blade portion 10, the conflat flange 17 and the annular member 6 are separated from each other. Between, that is, blade portion 16 and blade portion 19
Since there is a portion where the gasket 20 is sandwiched by and, it is possible to reliably prevent further leakage from occurring.

At this time, since the volume of the void formed between the conflat flange 17 and the sealing plug 4 is smaller than the volume of the space 2 in the double structure, the inside of this void is at atmospheric pressure. Even in such a state, the pressure in the space 2 hardly rises. Therefore, the function of the vacuum heat insulator is not impaired. For example, outline W500 × H1000 ×
D500mm, heat insulation thickness 35mm heat insulation container outer diameter 70
With a mm sealing flange, the internal volume of the double wall is approximately 71 liters. On the other hand, since the volume of the void is as small as about 5 × 10 ⁻³ liter, the pressure inside the space 2 is hardly affected.

As shown in the drawing, the void 22 formed between the conflat flange 17 and the sealing plug 4 can be filled with the filler 22. As a result, the substantial volume of the void can be significantly reduced, and the pressure increase in the space 2 at the time of the slow leak can be significantly reduced. As the filler 22, epoxy resin, silicone resin, polyester resin, inorganic fibers / powder with less outgas, metal fibers / grains, etc. can be used, and it is preferable to densely fill them.

This filling material 22 is attached to the conflat flange 17 by, for example, densely spraying it after the exhaust port 1 is vacuum-sealed by the sealing plug 4 and before the conflat flange 17 is attached. With this, filling can be performed.

FIG. 2 shows another embodiment of the present invention.
Here, instead of the conflat flange 17 described above, a thin metal disk 23 is welded to the end surface of the annular member 6 by a weld 24. Even in this case, double vacuum sealing can be performed in the same manner, but since only the disc 23 is welded, workability can be improved and cost can be reduced as compared with the case of FIG. The vacuum sealing unit can be made compact. It should be noted that there is no problem even if the blade portion 16 is present in the second step portion 15 of the annular member 6 as shown in the drawing, and the disc 23 is filled with the filler 22 while leaving the blade portion 16 left.
Can be covered.

[0018]

As described above, according to the present invention, with respect to the inside of the double wall, there is provided the first vacuum sealing portion for vacuum-sealing the exhaust port for evacuating the inside of the double wall after the vacuum exhaust. Since the second vacuum sealing section for vacuum sealing a portion outside the first vacuum sealing section is provided, even if a slow leak occurs in the first vacuum sealing section, With the presence of the vacuum sealing portion of the above, a reliable vacuum sealing state can be maintained, and at this time, the second vacuum sealing portion seals the outside of the portion vacuum-sealed by the first vacuum sealing portion. Because it is something that stops
Stable work is possible and reliable sealing can be performed, and the volume of the gap between the first vacuum sealing portion and the second vacuum sealing portion is equal to the volume inside the double wall. Since it can be made significantly smaller than the above, even if a slow leak occurs from this gap into the double wall, the pressure increase in the double wall is small, and therefore the required degree of vacuum can be maintained. it can.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of a vacuum sealing structure according to the present invention.

FIG. 2 is a diagram showing another embodiment of the vacuum sealing structure according to the present invention.

FIG. 3 is a diagram showing a vacuum sealing structure of a conventional vacuum heat insulator.

[Explanation of symbols]

 1 Exhaust Port 4 Sealing Plug 8 Blade 10 Blade 11 Gasket 16 Blade 17 Conflat Flange 19 Blade 20 Gasket

Claims (2)

[Claims] 1. A vacuum sealing structure of a vacuum heat insulator in which the inside of a double wall is evacuated, wherein an exhaust port for evacuating the inside of the double wall is evacuated and then vacuum-sealed. A vacuum heat insulating body, comprising: a sealing part; and a second vacuum sealing part for vacuum-sealing a portion outside the first vacuum sealing part in the double wall. Vacuum sealed structure. 2. The vacuum sealing structure for a vacuum heat insulator according to claim 1, wherein a filler is filled between the first vacuum sealing portion and the second vacuum sealing portion.