JPH06169850A - Metallic vacuum double container and its manufacture - Google Patents

Abstract

PURPOSE:To facilitate vacuum sealing processing and to execute the same at a low cost by disposing a sealing material formed by low temperature fused glass having a specified softening temperature in an exhaust port of an inner container or an outer container, evacuating a gap between the inner and outer containers at a temperature lower than the softening temperature of the sealing material, and sealing the exhaust port at a temperature higher than the softening temperature. CONSTITUTION:A gap 5 between an inner container 1 and an outer container 4 is taken as a vacuum heat insulating layer, and an exhaust port 11 is bored in a recess part 10 of the base member 3 of the outer container. A sealing material 12 formed by low temperature fused glass having a softening point of 200-600 deg.C is fitted at a space from the exhaust port 11. The double container A is heated in a vacuum heating furnace at such a temperature not to soften the sealing material 12 to discharge air. The sealing material is softened at a temperature above the softening point to seal the exhaust port 11. Accordingly, the working temperature of the vacuum heating furnace is lowered, the equipment cost is reduced, a process of removing an oxide on the surface of the container is omitted, and a large amount of products can be stably processed in the sealing process. The metallic material of the container can be increased in hardness by low temperature anneal so as to reduce its thickness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal vacuum double container such as a portable thermos, a pot, a jar, etc., in which an exhaust port formed in either an inner container or an outer container is made of a low temperature melting glass. With regard to those sealed with.

[0002]

2. Description of the Related Art As a method of manufacturing a metal vacuum double container, for example, a method of evacuating a chip tube attached to an outer container between an inner container and an outer container and then pressure-contacting and sealing the chip tube (Japanese Patent Laid-Open Publication No. 2000-242242) JP-A-59-37914 and JP-A-59-103.
No. 633) or an outer container is provided with an exhaust port, a metal brazing material is placed around the exhaust port, and a sealing member is placed on the metal brazing material so as to have a gap between the exhaust port and After heating and evacuating in a vacuum heating furnace, the temperature is raised to the melting temperature of the metal brazing material, the sealing member is brazed, and vacuum sealed (JP-A-58-192516), or an outer container. After making a small hole or cutout and arranging a metal brazing material in the vicinity of this, heat and exhaust in a vacuum heating furnace, and then raise the temperature to the melting temperature of the brazing material to cut the brazing material And vacuum sealing (Japanese Patent Application No. 1-10
6925) etc.

[0003]

However, these conventional vacuum sealing methods have the following problems. In the method using the tip tube described above, since the tip tube projects downward from the bottom of the outer container, it is necessary to attach a bottom cover to protect the tip tube, and the height of the product increases by the length. There is. In mass production,
Since it is necessary to seal and cut the chip tube for each product, there is a problem that the work becomes complicated. In addition, this sealing technique has a problem that not only high precision is indispensable and skillful technique is required, but also sealing sealing is often insufficient, and the degree of vacuum is deteriorated with the lapse of time and the heat insulating performance is deteriorated. Furthermore, in the sealing method using the tip tube, when exhausting gas between the inner and outer containers, the outer surface of the container is exposed to the atmosphere when heating the entire container to promote desorption of the gas adsorbed on the metal surface. It reacts with the oxygen in and is oxidized violently. Since the oxidized surface impairs the aesthetics and corrosion resistance of the product, a process for removing it is required, which causes a problem of increased cost.

On the other hand, in the sealing method using a brazing material, it is necessary to remove the material surface oxide around the exhaust port in order to improve the wettability of the brazing material with respect to the outer container material. Stainless steel suitable for use in thermos has a temperature of 950 ° C. under a pressure of 1 × 10 ⁻³ torr or less.
The above heating is performed, and a special vacuum heating furnace that can be used at a high temperature of 950 ° C or higher is required,
There is a problem that the equipment cost becomes expensive.

The present invention has been made in view of the above-mentioned circumstances, and the vacuum sealing process in the production of a metal vacuum double container can be easily performed at low cost, and the production cost can be reduced. The purpose is to provide heavy containers.

[0006]

In order to solve the above-mentioned problems, the invention described in claim 1 comprises an inner container and an outer container made of metal, and a space between these inner and outer containers is a vacuum heat insulating layer. In the method for producing a metal vacuum double container, a double container is formed by joining an inner container and an outer container having an exhaust port to one of the inner container and the outer container, and then forming a double container near the exhaust port. Of the low-temperature molten glass having a temperature of 200 to 600 ° C. is disposed, and then the double container is placed in a vacuum heating furnace to form a gap between the inner and outer containers at a temperature lower than the softening temperature of the sealing material. Vacuum evacuation, then raising the temperature of the double container to a temperature higher than the softening temperature of the sealing material to soften the sealing material and seal the exhaust port. It is a manufacturing method.

According to a second aspect of the present invention, there is provided a metal vacuum double container comprising a metal inner container and an outer container, wherein a space between the inner and outer containers is a vacuum heat insulating layer. A metal vacuum double container characterized in that an exhaust port formed in either one of the outer containers is vacuum-sealed with a sealing material made of low-temperature molten glass having a softening temperature of 200 to 600 ° C. .

[0008]

In the metal vacuum double container according to the present invention, the exhaust port formed in either the inner container or the outer container is vacuum-sealed with a sealing material made of low-temperature molten glass having a softening temperature of 200 to 600 ° C. By stopping, vacuum sealing can be performed at a relatively low temperature. Moreover, since the sealing material made of low-temperature molten glass is used, the wettability of the sealing material is good even if an oxide is present around the exhaust port, so that the exhaust port does not need to be exhausted like the conventional sealing method using a metal brazing material. A preliminary heat treatment for removing oxides by heating the surroundings to a high temperature of 950 ° C. or higher can be eliminated.

[0009]

1 to 3 are for explaining a first example of a method for manufacturing a metal vacuum double container according to the present invention. The metal vacuum double container manufactured here is formed by joining an inner container 1 made of stainless steel and an outer container 4 also made of stainless steel, and forming a space 5 between these inner container 1 and outer container 4. A portable thermos with a vacuum insulation layer. The outer container 4 has an outer container bottom member 3 at the lower end of a substantially cylindrical outer container body 2.
Are joined airtightly. The outer container bottom member 3 is provided with a hemispherical recess 10 at a substantially central portion thereof, and a small hole-shaped exhaust port 11 is provided at the center of the recess 10. It is desirable that the diameter of the exhaust port 11 is about 0.1 to 2.0 mm.

In order to manufacture this thermos, the inner container 1 and the outer container body 2 are airtightly joined to each other at the mouth portion, and the outer container bottom member 3 is airtightly joined to the outer container body 2 to be sealed before the sealing. A heavy container A (hereinafter referred to as a double container) is formed, and then FIG.
Further, as shown in FIG. 2, the rod-shaped sealing material 12 is attached in the recess 10 of the outer container bottom member 3 with the gap facing the exhaust port 11 with the mouth of the double container A facing downward. As the sealing material 12, low temperature molten glass having a softening point of 200 to 600 ° C. is used. As such a low temperature molten glass, B ₂ O _3-
PbO type, B ₂ O ₃ -ZnO type, PbO-B ₂ O ₃ -ZnO-S
iO ₂ system, PbO-B ₂ O ₃ -Al ₂ O ₃ -SiO ₂ system, PbO-
So-called solder glass such as B ₂ O ₃ —SiO ₂ system and PbO—B ₂ O ₃ —BaO—SiO ₂ system is used, and one having a coefficient of thermal expansion similar to that of stainless steel which is a material of the double container is preferable. .. To mount the rod-shaped sealing material 12 in the recess 10, it is sufficient to push the sealing material 12 into the recess 10. However, in order to prevent displacement of the sealing material 12, an adhesive agent is applied to both ends of the sealing material 12. It may be applied and fixed in the recess 10. Further, the shape of the sealing material 12 is not limited to the rod shape and may be a solid shape.

Next, the double container A with the sealing material 12 attached.
Is placed in a vacuum heating furnace while facing downward, and the inside of the furnace is evacuated and heated to be heated and evacuated. This heating exhaust gas is in the temperature range of 200 to 600 ° C. and the sealing material 1
The temperature is set so that 2 does not soften. The gas in the gap between the inner container 1 and the outer container 4 is discharged through the exhaust port 11. 1 x 10 ^-2
After evacuating to a pressure of torr or less, the inside of the furnace is 200 to 6
In the temperature range of 00 ° C. and at a temperature higher than the softening point of the sealing material 12, the sealing material 12 is softened and directly dropped by its own weight to the exhaust port 11 and its surroundings to seal the exhaust port 11. To do. After this vacuum sealing, the container is taken out of the furnace, and as shown in FIG. 3, the exhaust port 11 is sealed by the sealing material 12 made of low-temperature molten glass, and the space between the inner container 1 and the outer container 4 is closed. A stainless steel thermos (metal vacuum double container) having the vacuum heat insulating layer 6 formed thereon can be obtained. Through this vacuum sealing treatment, the double container is heated at a temperature of 200 to 600 ° C., and the hardness of the stainless steel which is the material of the double container is increased by low temperature annealing. Therefore, it is possible to reduce the thickness of the stainless steel plate required to obtain the impact resistance necessary for using the thermos and to make the container thin.

In the manufacturing method according to this embodiment, the exhaust port of the metal double container is sealed with a sealing material made of low-temperature molten glass having a softening temperature of 200 to 600 ° C. Compared with this, the vacuum sealing temperature can be lowered, so the operating temperature of the vacuum heating furnace can be designed to be low,
The equipment cost can be reduced and the manufacturing cost of the product can be reduced. This low temperature molten glass has an advantage that good wettability can be achieved without impairing the wettability even if an oxide is present on the surface of the double container. Therefore, the step of heating the surface of the double container to a high temperature to remove the oxide can be omitted, and the manufacturing cost of the vacuum double container can be reduced. Further, as compared with the conventional manufacturing method using a tip tube, a compact product can be manufactured without the projection of the remaining tip tube.
In the sealing step, a large amount of products can be stably processed at the same time in a vacuum heating furnace without human intervention, which facilitates mass production and reduces manufacturing costs. Further, in the process of vacuum evacuation between the inner and outer containers, since the entire container is heated in vacuum, the outer surface of the container is not significantly oxidized, and the removal process by the post-treatment can be omitted, and the cost can be reduced. . Further, all the operations of vacuum exhaustion and sealing can be performed at a relatively low temperature of about 200 to 600 ° C., and the metal material such as stainless steel forming the container can increase the hardness by low temperature annealing. The container can be made thin by using high hardness stainless steel, and the weight of the vacuum double container can be reduced.

FIGS. 4 and 5 are for explaining a second example of the method for manufacturing a metal vacuum double container according to the present invention. The double container B shown in these figures has substantially the same components as those shown in FIGS. 1 and 2, and the same components are designated by the same reference numerals. The double container B shown in FIGS. 4 and 5 has a long groove 1 at the center of the bottom surface side of the outer container bottom member 3.
3 is formed, and a slit-shaped elongated hole 14 (exhaust port) is formed in the bottom of the elongated groove 13. Then, as shown in FIG. 5, a rod-shaped sealing material 12 made of low-temperature molten glass and having a length shorter than the length of the slit-shaped long hole 14 is arranged in the long groove 13 of the double container B, and then, As in the above example, the double container B is put in a vacuum heating furnace, and 200 to 6
After exhausting while heating to a temperature range of 00 ° C. and at a temperature at which the sealing material 12 does not soften, and exhausting to a pressure of 1 × 10 ⁻² torr or less, the inside of the furnace is sealed in a temperature range of 200 to 600 ° C. and sealed. The sealing material 1 is heated to a temperature equal to or higher than the softening point of the stopper 12
The slit-shaped long hole 14 is sealed by softening and flowing 2 to obtain a stainless steel thermos (vacuum double container).

FIG. 6 is for explaining a third example of the method for manufacturing a metal vacuum double container according to the present invention. The double container C shown in this figure includes substantially the same components as those shown in FIGS. 1 and 2, and the same components are designated by the same reference numerals. The double container C shown in FIG. 6 is an outer container body 2
A pocket-shaped recess 10 is provided in the shoulder portion of the device, and a small-hole-shaped exhaust port 11 is formed in the recess 10. To seal the double container C, a rod-shaped sealing material 12 made of low-temperature molten glass is attached in the recess 10 with the opening of the double container C facing upward, and this is placed in a vacuum heating furnace. ,
As in the previous example, exhaust is performed while heating in the temperature range of 200 to 600 ° C. and at a temperature at which the sealing material 12 does not soften, and 1 ×
After exhausting to a pressure of 10 ^-2 torr or less,
In the temperature range of 0 to 600 ° C. and at a temperature higher than the softening point of the encapsulating material 12, the encapsulating material 12 is softened and directly dropped to the exhaust port 11 and its surroundings by its own weight to exhaust port 11.
Is sealed. After this vacuum sealing, the container is taken out of the furnace to obtain a stainless steel thermos (vacuum double container).

In the manufacturing method according to the present embodiment, the same effect as that of the previous embodiment can be obtained, and since the recess 10 and the exhaust port 11 are formed in the shoulder portion of the double container C, the vacuum of the double container C is reduced. When sealing is performed, the double container C can be installed in a vacuum heating furnace in a normally standing state, and a supporting member for supporting the double container is not required, so that the double container can be installed and taken out extremely. It will be easy.

[0016]

As described above, according to the present invention,
By sealing the exhaust port formed in one of the metal double containers with a sealing material made of low-temperature molten glass having a softening temperature of 200 to 600 ° C., a vacuum seal is obtained as compared with the conventional brazing method. Since the stop temperature can be lowered, the operating temperature of the vacuum heating furnace can be designed to be low, the facility cost can be reduced, and the manufacturing cost of the product can be reduced. The low-temperature molten glass used in the present invention has an advantage that good wettability can be achieved without impairing the wettability even if an oxide is present on the surface of the metallic double container. Therefore, the step of heating the surface of the metal double container to a high temperature to remove the oxide can be omitted, and the manufacturing cost of the vacuum double container can be reduced.
Further, as compared with the conventional manufacturing method using a tip tube, a compact product can be manufactured without the projection of the remaining tip tube. In the sealing step, a large amount of products can be stably processed at the same time in a vacuum heating furnace without human intervention, which facilitates mass production and reduces manufacturing costs. Furthermore, regarding the process of vacuum evacuation between the inner and outer containers,
Since the entire container is heated in vacuum, the outer surface of the container is not significantly oxidized, the removal process by post-treatment can be omitted, and the cost can be reduced. Further, all the operations of vacuum exhaustion and sealing can be performed at a relatively low temperature of about 200 to 600 ° C., and the metal material such as stainless steel forming the container can increase the hardness by low temperature annealing. The container can be made thin by using a metal material having high hardness, and the weight of the vacuum double container can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a double container to which a sealing material is attached, for explaining a first example of a method for manufacturing a metal vacuum double container according to the present invention.

FIG. 2 is a bottom view of the same double container.

FIG. 3 is an enlarged cross-sectional view of a main part of a vacuum double container obtained by performing vacuum sealing processing on the same double container.

FIG. 4 is a cross-sectional view of a double container with a sealant attached, for explaining a second example of the method for manufacturing a metal vacuum double container according to the present invention.

FIG. 5 is an enlarged bottom view of the main part of the same double container.

FIG. 6 is a cross-sectional view of a double container to which a sealing material is attached, for explaining a third example of the method for manufacturing a metal vacuum double container according to the present invention.

[Explanation of symbols]

1 ... inner container, 2 ... outer container body, 3 ... outer container bottom member, 4 ... outer container, 5 ... void, 6 ... vacuum heat insulating layer, 1
0 ... recess, 11 ... exhaust port, 12 ... sealing material, 13 ...
… Long groove, 14 …… Slit-like long hole, A, B, C …… Double container before sealing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Eiji Otsuka, 1-16-7 Nishishinbashi, Minato-ku, Tokyo Within Nihon Oxygen Co., Ltd. (72) Inventor Jun Yamaki 1-16-7 Nishishinbashi, Minato-ku, Tokyo No. Japan Oxide Co., Ltd.

Claims (2)

[Claims] 1. A method for producing a metal vacuum double container comprising a metal inner container and an outer container, wherein a space between the inner and outer containers is a vacuum heat insulating layer, wherein either the inner container or the outer container is used. An inner and outer container having an exhaust port is joined to one side to form a double container, and a sealing material made of low-temperature molten glass having a softening temperature of 200 to 600 ° C. is arranged in the vicinity of the exhaust port, The double container is placed in a vacuum heating furnace, the space between the inner and outer containers is evacuated at a temperature lower than the softening temperature of the sealing material, and then the double container is heated to a temperature higher than the softening temperature of the sealing material. Then, the method for producing a metal vacuum double container is characterized in that the sealing material is softened and fluidized to seal the exhaust port. 2. A metal vacuum double container comprising a metal inner container and an outer container, wherein a space between the inner and outer containers is a vacuum heat insulating layer, wherein the metal container is formed in one of the inner container and the outer container. A metal vacuum double container, characterized in that the formed exhaust port is vacuum-sealed with a sealing material made of low-temperature molten glass having a softening temperature of 200 to 600 ° C.