JPH0366332A - Manufacture of thermos bottle made of metal - Google Patents

Abstract

PURPOSE:To surely execute sealing and to realize a full automation by forming a double structure by joining an outer bottle and an inner bottle, placing a brazing filler metal in an exhaust hole, heating it to a vaporization temperature or above of a binder, and also, to a melting temperature or below of the brazing filler metal, executing a vacuum exhaust, raising a temperature up to the melting temperature of the brazing filler metal and bringing the exhaust hole to vacuum sealing. CONSTITUTION:In about the center part of an outer bottle bottom part 6, a hemispherical recessed part 9 is formed toward the direction of a cavity part 3, and in the center part of the recessed part 9, an exhausting hole 10 is pierced and a double wall container is inverted, and a brazing filler metal 11 formed by kneading a brazing filler metal into a binder is piled up so as to cover the exhausting hole 10. Subsequently, the outer bottle bottom part 6 is turned upward and placed in a vacuum heating furnace, and by performing a vacuum heating processing, the exhausting hole 10 is sealed by the brazing filler metal 11. The vacuum heating processing is constituted of a vacuum exhausting process for holding the brazing filler metal at a vaporization temperature or above of the binder, and also, at the melting temperature or below of the brazing filler metal, and a sealing process for holding it at a melting temperature or above of the brazing filler metal. When the vacuum exhausting process is performed, the brazing filler metal 11 becomes a porous brazing filler metal, air in the cavity part 3 can be exhausted through the porous brazing filler metal, and by heating it to the melting point or above of the brazing filler metal, the exhausting hole 10 is sealed surely.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for manufacturing a metal double-walled container manufactured by vacuum heat treatment in a vacuum heating furnace.

[Prior Art] A known metal thermos flask has a double structure in which an inner metal bottle, an outer metal bottle, and a bottle mouth are joined together at the mouth, and the gap between the inner and outer bottles is vacuum-sealed. It is being

As a method for manufacturing such a metal thermos flask, the method disclosed in Japanese Patent Publication No. 36766/1983 is known. The metal thermos manufactured by this method has a cylindrical inner bottle with a bottom, as shown in Figure 15! A vacuum insulation layer is formed by vacuum-sealing the gap 3 between the outer bottle 2 and the outer bottle 2, and the diameter-reduced opening of the outer bottle body 4 is connected to the opening 1a of the inner bottle 1. At the same time, the outer bottle bottom 6 is joined to the open end 5 on the bottom side of the outer bottle body 4 to be integrated. Approximately in the center of this outer bottle bottom 6 is a stepped portion 6 extending toward the cavity 3.
a is formed, and an exhaust port 7 is also formed approximately at the center of the stepped portion 6a, and this exhaust port 7 is vacuum-sealed by brazing a sealing member 8 in a vacuum. .

This vacuum sealing is performed by standing the outer bottle upside down with the bottom 6 facing upward, filling the stepped portion 6a with solid brazing filler metal at appropriate intervals, and placing the sealing member 8 so that there is a gap between it and the stepped portion 6a. Supported and subjected to vacuum heat treatment in a vacuum heating furnace, the solid brazing material is melted while the cavity 3 is evacuated, and the sealing member 8 is dropped by its own weight to seal the exhaust port 7. method was used.

[Problems to be Solved by the Invention] However, in such a vacuum sealing method, during evacuation, the solid wax is The filler material and the sealing member 8 may be displaced from the exhaust port 7, or the brazing material may spread unevenly around the exhaust port, causing vacuum sealing failure.

Furthermore, it is difficult to automate the process of piling up the brazing filler metal at appropriate intervals and disposing the sealing member 8 on top of it, and it must be done manually, and the sealing member 8 must be provided only for vacuum sealing. However, this has caused an increase in manufacturing costs.

This invention was made to solve the above problems, and is a metal thermos flask that can reliably vacuum seal at a low manufacturing cost without using a sealing member, and can further automate the manufacturing process. The purpose is to provide a manufacturing method for.

[Means for solving the problem 1 The method for manufacturing a metal thermos flask according to claim 1 of the present invention includes:
In manufacturing a metal thermos flask, which consists of a metal inner bottle and an outer bottle, and the gap between the inner and outer bottles is a vacuum insulation layer, the outer bottle has an exhaust hole and the inner bottle has a spout. After joining to form a double structure, a brazing filler metal made by kneading powdered or granular metal brazing material into a binder is placed so as to cover the exhaust hole and placed in a vacuum heating furnace to vaporize the binder. The present invention also claims that the cavity is heated to a temperature above the melting temperature of the metal solder and below the melting temperature of the metal solder, the inside of the gap is evacuated in this state, and then the temperature is raised to the melting temperature of the metal solder to vacuum seal the exhaust hole. In the manufacturing method described in Item 2, the solution is to form a recess in the outer bottle and to form an exhaust hole in the center of the recess.

[Operation] After placing a brazing material made by kneading metal solder in a binder so as to cover the exhaust hole bored in the outer bottle, it is heated in a vacuum heating furnace at a temperature above the vaporization temperature of the binder and of the metal solder. When vacuum heating is performed below the melting temperature, only the binder in the brazing material vaporizes, so the brazing material becomes a porous metal solder. At this time, air within the cavity 3 can be exhausted through the porous metal solder. After the inside of the gap is sufficiently evacuated, the temperature is further increased to melt the porous metal solder, thereby making it possible to vacuum-seal the exhaust hole.

Further, in the manufacturing method according to claim 2 of the present invention, since the exhaust hole is formed in the center of the recess, the fluidized brazing material can be efficiently poured into the exhaust hole.

[Example] Hereinafter, this invention will be explained in detail along with examples.

1 to 3 are for explaining a first embodiment of the present invention.

Figures 1 and 2 show the state of the metal thermos manufactured in this invention before vacuum sealing, and Figure 2 shows the exhaust hole! It is an enlarged view of the main part of 0.

The difference between the metal thermos flasks shown in FIGS. The exhaust hole 10 is drilled and the exhaust hole 10 is directly filled with the brazing material without using the sealing member 8! 1 to perform vacuum sealing.

To perform vacuum sealing according to the manufacturing method of the present invention, first, as shown in FIGS. An exhaust hole 10 is formed in the center of the recess 9, the double-walled container is inverted, and a brazing metal is kneaded in a binder so as to cover the exhaust hole IO. Serve with II. Then, the bottle is placed in a vacuum heating furnace with the part in which the exhaust hole 10 is formed, that is, the bottom 6 of the outer bottle facing upward, and vacuum heating treatment is performed to seal the exhaust hole 10 with the brazing material 11.

This vacuum heat treatment includes a vacuum evacuation process that maintains the temperature at approximately 300 to 600°C, which is above the vaporization temperature of the binder and below the melting temperature of the metal solder, and a
It consists of a sealing step that is maintained at 00°C.

First, when a vacuum evacuation step is performed at 300 to 600° C., the binder is vaporized, so that the brazing filler metal 11 becomes a porous metal brazing material. The air within the cavity 3 can be exhausted to the outside through this porous metal solder.

After sufficiently exhausting the air in the cavity 3 in this state, the exhaust hole 10 is sealed by heating the porous metal solder to a temperature higher than its melting point. At this time, since the porous metal solder is melted and in a liquid state, it accumulates in the recess 9 due to its surface tension and also enters the exhaust hole 10 due to capillary action, thereby reliably sealing the exhaust hole 10. can do. In addition, since the metal solder is melted in a vacuum, the gas generated during melting can also be exhausted, making it possible to braze without forming bubbles (voids) and leaking. There is no need to worry about

Furthermore, if the diameter of the exhaust hole 10 is too small, the exhaust will not be sufficient, and if it is too large, the surface tension of the brazing filler metal 11 will not be able to close it completely. l~2.0 nm is suitable.

The brazing filler metal 11 is made by kneading metal brazing material into a binder, and includes Ni, which has few components that evaporate in vacuum,
Ag, Cu, Au, 5nSAI2. Various Ti5P-based metal solders can be used in granular or powdered form. Furthermore, if a metal such as stainless steel or carbon steel, which has a melting point higher than that of the metal solder, is made into powder or scales and kneaded into the binder together with the metal solder, the diameter of the exhaust hole IO can be made larger. It becomes easier to create the exhaust hole IO, and the number of defects is reduced. Furthermore, in the exhaust process, not only can sufficient exhaust be performed in a short time, but the amount of brazing filler metal 11 that seals the exhaust hole IO can also be reduced, which helps reduce manufacturing costs. Helpful.

The binder also has a temperature lower than that of the metal solder, preferably 3
It is not particularly limited as long as it is an organic compound that vaporizes at 00 to 600°C, and for example, starch treated with acid or alkali, styrene-vinyl acetate copolymer emulsion, etc. can be suitably used.

As described above, the cavity 3 of the metal thermos flask can be made into a vacuum heat insulating layer without using a sealing member.

4 to 6 all show the state of the second embodiment of the manufacturing method of the present invention before vacuum sealing,
5 and 6 are both enlarged views of the main parts of FIG. 4, and FIG. 7 shows the state after vacuum sealing.

This example differs from the first example described above in the shape of the four parts 9 and the number of exhaust holes 10. In this example,
As shown in FIGS. 4 to 6, a groove-shaped recess 9 is formed approximately in the center of the outer bottle bottom 6, and two exhaust holes 10 and 10 are bored at both ends of the bottom of the four parts 9. did. By providing a plurality of exhaust holes IO in this manner, the cavity 3 can be evacuated in a shorter time without increasing the diameter of each exhaust hole.

In this example, two exhaust holes IO are bored, but the number of exhaust holes IO is not limited to this. Any number of holes can be provided.

8 and 9 both show the state of the third embodiment of the manufacturing method of the present invention before vacuum sealing.

The third embodiment differs from the above embodiment in that a recess 9 having a larger diameter than the recess in the first embodiment is formed in the center of the outer bottle bottom 6, and a plurality of recesses are provided concentrically with this recess 9. Exhaust holes I
O... are bored and brazing filler metal II is filled in an annular shape so as to close each exhaust hole lO.... In this way, vacuum evacuation can be performed in a short time as in the second embodiment. Furthermore, in this example, since the brazing filler metal Il is arranged in an annular shape, the amount of brazing filler metal used can be further reduced.

FIG. 10 shows the state before vacuum sealing of the fourth embodiment of the manufacturing method of the present invention. In this example, the outer bottle body 4
An annular recess 9 is provided on the bottom side of the outer bottle at the joint between the open end 5 and the outer bottle bottom 6, and an exhaust hole l is provided at the bottom of the recess 9.
O... were provided intermittently, and a brazing filler metal 11 was placed in an annular shape so as to close each exhaust hole lO....

11 to 13 all show the state before vacuum sealing of the fifth embodiment of the manufacturing method of the present invention. This product is different from the above embodiments in that the outer bottle body 4 is provided with a V-shaped recess 9 that projects toward the cavity 3, and the bottom of the recess 9 is provided with an elongated exhaust hole IO. This exhaust hole! This is where the brazing filler metal 11 is placed so as to cover the hole 0. In this example, when performing the vacuum heat treatment, the thermos is placed horizontally and turned over so that the recess 9 faces upward. In this case, the length of the elongated exhaust hole 10 formed in the outer bottle body 4 is not particularly limited, but the width of the hole is the same as the diameter of the exhaust hole in each of the above embodiments. The spacing is preferably about 0.1 to 2.0 mm.

In addition, in this example, the exhaust hole IO is bored in the center of the outer bottle body 4, but if the exhaust hole IO is bored in the upper part of the outer bottle body 4, the thermos flask can be heated during vacuum heating treatment. There is no need to turn it upside down or turn it over.

In each of the first to fifth embodiments described above, the exhaust hole 10 is provided at the bottom of the recess 9, but the manufacturing method of the present invention is not limited to this. A hole 10 may also be provided.

FIG. 14 shows the state of the sixth embodiment of the present invention before the vacuum pair +h. What is different from the first embodiment shown in FIGS. 1 to 3 is that there is no recess 9 in the center of the bottom 6 of the outer bottle, and there is no exhaust hole! Only the exhaust hole 10 is drilled, and the brazing material 11 is placed so as to close the exhaust hole 10. If the recess 9 is not provided in this manner, the manufacturing process of the metal thermos flask can be further simplified.

[Effects of the Invention] As explained above, the manufacturing method according to claim 1 of the present invention comprises a metal inner bottle and an outer bottle, and the gap between the inner and outer bottles is a vacuum insulation layer. When manufacturing thermos flasks, an outer bottle with an exhaust hole and an inner bottle are joined at the mouth to create a double structure, and then powdered or granular metal solder is kneaded into a binder to create a brazing material. is arranged so as to cover the exhaust hole, and is housed in a vacuum heating furnace and heated to a temperature above the vaporization temperature of the binder and below the melting temperature of the metal solder. In this state, the inside of the void is evacuated, and then the metal solder is heated. Since the temperature is raised to the melting temperature and the exhaust hole is vacuum sealed,
Vacuum sealing of the gap can be performed without using a sealing plate, and the occurrence of sealing failures due to displacement of the sealing plate can be reduced.

Further, according to this method, the operation of supplying the brazing material only requires placing the brazing material on the bored exhaust hole, so the workability is good and the manufacturing process can be fully automated.

Furthermore, in the conventional sealing method, the large-diameter exhaust hole was sealed with a sealing plate, which required 2 to 3 g of brazing material. Since the soldering material is directly sealed with a brazing material, the amount of brazing material used is sufficient to be about 0.2 to 0.5 g, and it is also possible to reduce manufacturing costs.

Further, in the manufacturing method according to claim 2 of the present invention, the outer bottle is formed with recessed portions, and the exhaust holes are bored in the center of the four portions, so that the melted brazing material is efficiently absorbed during the vacuum heat treatment. It is possible to seal the exhaust hole.

[Brief explanation of drawings]

1 to 14 each show an example of the method for manufacturing a metal thermos flask according to the present invention, and FIG. 1 shows a schematic configuration of a metal thermos flask for explaining the first embodiment. Figures 1 and 2 are shown in Figure 1. FIG. 3 is an enlarged view of the main parts of the recess and exhaust hole of the scrap metal thermos flask, and FIG. 3 is an enlarged view of the main parts showing the state of the exhaust hole shown in FIG. 2 after vacuum sealing. Fig. 4 is a schematic configuration diagram of a metal thermos flask for explaining the second embodiment, and Figs. 5 and 6 are enlarged views of essential parts showing the state of the recess and exhaust hole shown in Fig. 4. Figure, 7th
This figure is an enlarged view of the main part showing the state after vacuum sealing of the exhaust hole shown in FIG. 4. FIG. 8 is a schematic configuration diagram of a metal thermos flask for explaining the third embodiment, and FIG. 9 is an enlarged view of essential parts of the recess and exhaust hole shown in FIG. 8. FIG. 10 is a schematic configuration diagram of a metal thermos flask for explaining the fourth embodiment. FIG. 11 is a schematic configuration diagram of a metal thermos flask for explaining the fifth embodiment, and FIGS. 12 and 13 are both of the first embodiment.
FIG. 2 is an enlarged view of the four parts of FIG. 1 and the main parts of the exhaust hole. FIG. 14 is a schematic configuration diagram of a metal thermos flask for explaining the sixth embodiment. FIG. 15 is a schematic diagram showing an example of a conventional method for manufacturing a metal thermos flask. l...Inner bottle, 2...Outer bottle, 3...Gap, 9...Recess, 10...Exhaust hole, ! ■・・・Brazing material.

Claims (2)

[Claims] (1) When manufacturing a metal thermos flask, which consists of a metal inner bottle and an outer bottle, and the gap between the inner and outer bottles is a vacuum insulation layer, an outer bottle with an exhaust hole and an inner bottle are used. After joining at the mouth to form a double structure, a brazing filler metal made by kneading powdered or granular metal brazing material in a binder is placed so as to cover the exhaust hole, and stored in a vacuum heating furnace. It is characterized by heating to a temperature above the vaporization temperature of the binder and below the melting temperature of the metal solder, evacuating the inside of the gap in this state, and then raising the temperature to the melting temperature of the metal solder to vacuum seal the exhaust hole. How to make a metal thermos flask. (2) The method for manufacturing a metal thermos flask according to claim 1, characterized in that a recess is formed in the outer bottle and an exhaust hole is bored in the center of the recess.