JP2002345655A - Vacuum double container and sealing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mechanize the setting work of a brazing filler metal in the exhausting and sealing processes of a vacuum double container by contriving the shape of the bottom surface of the outer bin of the vacuum double container and using an almost spherical brazing filler metal. SOLUTION: In the vacuum double container provided with a tightly sealed space 14 between metallic inner bin 11 and outer bin 12, a recessed tapered part 16 whose center part is recessed is formed on the bottom surface 15 of the outer bin 12, one, two or more exhaust holes 20 communicated with the tightly sealed space 14 are provided on the center part of the tapered part 16 and the exhaust holes 20 are sealed by using the almost spherical brazing filler metal. Also, a recessed part 19 deformed in the plane view and recessed stepwise is formed at the center part of the tapered part 16, the brazing filler metal is held by the recessed part 19 in the state of floating from the bottom surface of the recessed part 19 and the exhaust holes 20 are provided on the bottom surface or side face of the recessed part 19.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum double container having a sealed space between a metal inner bottle and an outer bottle, and a method of sealing the double container.

[0002]

2. Description of the Related Art Insulation containers, generally called thermos bottles or jars, comprise an inner bottle and an outer bottle manufactured by press-forming a sheet metal such as stainless steel. For example, FIG.
As shown in the figure, the opening edges 53 of the inner bin 51 and the outer bin 52
Are welded together to form a closed space 54 between the inner bin 51 and the outer bin 52. Normally, the bottom 55 of the outer bottle 52
By evacuating the air in the closed space 54 from the exhaust hole 56 formed in the inner container 51, a vacuum layer is formed between the inner bottle 51 and the outer bottle 52, and a vacuum double container (thermal insulation container) 50 is formed. In recent years, electric pots have been commercialized that employ this type of vacuum double container as a tank and can maintain the temperature without energizing an electric heater.

In the process of evacuating and closing the vacuum double container 50, the vacuum double container 50 before evacuation is attached to the bottom surface 5 of the outer bottle 52.
5 is placed on a predetermined table in a state where it is face down so that it faces upward. Then, while the table on which the plurality of vacuum dual containers 50 are placed sequentially passes through the preparation chamber (low vacuum chamber), the vacuum chamber, the brazing chamber, and the cooling chamber, the evacuation of each vacuum dual container 50 and Sealing is performed.

Heretofore, lead-containing glass has been used as a brazing material for closing the exhaust hole 56 after the air in the closed space 54 is evacuated from the exhaust hole 56. Lead-containing glass is suitable as a brazing material because it melts at a lower temperature than lead-free glass. The lead-containing glass brazing material has a substantially cylindrical shape because it is manufactured by extrusion and cutting. Such a brazing material is previously placed in a concave portion 57 including an exhaust hole 56 formed in a bottom surface 55 of the vacuum double container 50 before evacuation. Then, after the evacuation of the vacuum double container 50 is performed in the vacuum chamber, the brazing material is melted in the brazing chamber and the evacuation hole 56 is closed.

[0005] The work of placing the brazing material in the recess 57 of each vacuum double container 50 has been performed manually by using tweezers or the like. In addition, the brazing material placed in the concave portion 57 may be vibrated during the movement of the mounting table or during the evacuation, for example.
In some cases, a thin plate covering the concave portion 57 is welded to the bottom surface 55 so that the thin plate does not jump out of the concave portion 57 when it swings. In this case, the work which has not been welded to the bottom surface 55 of the thin plate piece is lifted to set the brazing material in the recess 57.

[0006]

The work of placing the brazing material in the concave portion 57 in advance in the above-described vacuum evacuation and sealing steps of the vacuum double container is a manual operation, and requires a lot of man-hours.
This was a barrier to cost reduction. In particular, when a thin plate piece that covers the concave portion 57 is provided, the work of setting the brazing material in the concave portion 57 by lifting one end of the thin plate piece is time-consuming, and thus improvement in workability is required. Was.

[0007] Further, the lead-containing glass brazing material conventionally used has disadvantages in that lead may harm the human body and recycling of the vacuum double container becomes difficult. For this reason, the use of a lead-free glass brazing material has been studied. As described above, the conventional lead-containing glass brazing material has a substantially cylindrical shape, whereas the lead-free glass brazing material can be easily manufactured to have a substantially spherical shape by free fall. This substantially spherical brazing material has a property of rolling more easily in an arbitrary direction than the conventional substantially cylindrical brazing material.

[0008] In view of the above, according to the present invention, by devising the shape of the bottom surface of the outer bottle of the vacuum double container and using a substantially spherical brazing material, it is possible to set the brazing material in the evacuation and sealing steps of the vacuum double container. The purpose is to enable mechanization.

[0009]

SUMMARY OF THE INVENTION A vacuum double container according to the present invention is a vacuum double container having a sealed space between a metal inner bottle and an outer bottle, wherein a concave tapered portion is formed on the bottom surface of the outer bottle. One or more exhaust holes which are formed and communicate with the sealed space are provided at the lowermost portion or near the lowermost portion of the tapered portion, and the exhaust holes are sealed using a substantially spherical brazing material.

According to such a configuration, in the evacuation and sealing step of the vacuum double container, a substantially spherical shape is formed from above the tapered portion of the vacuum double container in a state where the bottom of the outer bottle is turned up. When the brazing material falls, the brazing material rolls on the tapered portion and is set near the lowermost portion of the tapered portion or near the exhaust hole formed near the lowermost portion. Even if the brazing material moves in the outer circumferential direction from the lowermost portion or the vicinity of the lowermost portion of the tapered portion due to vibration at the time of exhaustion, the brazing material rolls again along the inclined surface of the tapered portion if the vibration stops, and the lowermost or Return to near the bottom. Therefore, it is possible to automate (mechanize) the setting of the brazing filler metal without manual operation as in the related art.

Preferably, a concave portion having a stepped concave shape in plan view is formed at or near the lowermost portion of the tapered portion, and the brazing material is held in the concave portion while floating from the bottom surface of the concave portion. An exhaust hole is provided on the bottom or side surface of the recess. According to such a configuration, since the brazing material that has fallen to the lowermost portion or the vicinity of the lowermost portion of the tapered portion as described above is held in the concave portion, the brazing material is moved to the lowermost portion of the tapered portion or the like by vibration at the time of exhaustion. The phenomenon of moving from the vicinity of the lowermost portion toward the outer periphery hardly occurs. In addition, since the concave portion is irregular in plan view, the substantially spherical brazing material does not completely cover the opening of the concave portion, and the brazing material is held in a state of floating from the bottom surface of the concave portion. Communication between the closed space and the outside is ensured, and the closed space is smoothly exhausted.

The lowermost portion of the tapered portion is preferably located at the center of the tapered portion. However, the lowermost portion of the tapered portion may be provided at a position shifted from the center of the tapered portion.

It is preferable that at least about one third of the length from the center to the outer periphery of the bottom surface of the outer bin is formed as a concave tapered portion, and an annular wall is formed on the outer periphery of the tapered portion. According to such a structure, even if the brazing material may move in the outer circumferential direction from the lowermost portion or the vicinity of the lowermost portion of the tapered portion due to vibrations at the time of exhausting, the annular wall portion formed on the outer circumference of the tapered portion. , And rolls again along the inclined surface of the tapered portion and returns to the lowermost portion or the vicinity of the lowermost portion.

Further, it is preferable that one or a plurality of preliminary concave portions are formed on the bottom surface outside the annular wall portion. According to such a configuration, even if the brazing material gets over the annular wall portion and goes out of the tapered portion, the brazing material is held in the preliminary concave portion. Thus, it is possible to prevent the brazing material from spilling from the vacuum double container.

Depending on the vibration direction, when the brazing material that has moved from the central portion (the lowermost portion or the vicinity of the lowermost portion) of the tapered portion to the outer peripheral portion due to vibrations at the time of exhaustion returns to the central portion along the inclined surface of the tapered portion. It may return in a spiral. In this case, it takes time until the brazing material returns to the center of the tapered portion, which is not preferable. Therefore, it is preferable that one or a plurality of grooves or ridges extending radially from the central portion to the outer peripheral portion are formed in the tapered portion.
By doing so, the brazing material returning from the outer peripheral portion to the central portion of the tapered portion returns to the central portion promptly along the groove or the ridge without drawing a spiral.

The method for sealing a vacuum double container according to the present invention comprises:
In a vacuum double container having a sealed space between a metal inner bottle and an outer bottle, a concave tapered portion is formed on the bottom surface of the outer bottle and communicates with the sealed space at the lowermost portion or near the lowermost portion of the tapered portion. One or a plurality of exhaust holes are provided, and placed on a predetermined table in a state where the vacuum double container is face down so that the bottom surface of the outer bottle is at the top, and a spherical brazing material is dropped from above the tapered portion. After the brazing material is naturally dropped to the lowermost portion or the vicinity of the lowermost portion of the tapered portion and the enclosed space is evacuated in the vacuum chamber, the exhaust hole is formed by melting the brazing material located at the lowermost portion or the vicinity of the lowermost portion of the tapered portion. It is characterized by being sealed. According to such a sealing method, it becomes possible to automate (mechanize) the setting of the brazing filler metal without manual operation as in the related art.

Preferably, the taper angle of the tapered portion is
It is larger than the maximum inclination angle when the vacuum double container inclines due to the vibration at the time of evacuation of the closed space. Thus, the possibility that the brazing member set at the lowermost portion or the vicinity of the lowermost portion of the tapered portion moves to the outer peripheral portion of the tapered portion due to vibration is reduced.

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example of a vacuum double container according to a first embodiment of the present invention, wherein (a) is a bottom view,
(B) is a sectional view in a side view with the bottom face up. This vacuum double container 10 has an inner bottle 11 and an outer bottle 12 manufactured by press-forming a metal plate such as stainless steel.
Consists of The opening edges 13 of the inner bin 11 and the outer bin 12 are welded to each other to form a closed space 14 between the inner bin 11 and the outer bin 12.

The bottom surface 15 of the outer bin 12 is formed with a concave tapered portion 16 whose central portion is depressed. In the illustrated example, the radius of the tapered portion 16 is approximately の of the radius of the bottom surface 15, but may be at least about ３. An annular wall portion 17 is formed on the outer periphery of the tapered portion 16, and an annular preliminary concave portion 18 is formed outside the wall portion 17. However, instead of providing one annular preliminary concave portion 18 as shown, a plurality of preliminary concave portions may be arranged in an annular shape. This spare recess 1
Reference numeral 8 has a function of holding the brazing material spilled over the annular wall portion 17 from the tapered portion 16. Further, a stepped concave portion 19 is formed at the center of the tapered portion 16, and a small hole (exhaust hole) 20 that communicates the sealed space 14 with the outside is formed at the bottom surface.

FIG. 2 is an enlarged view showing a concave portion 19 and an exhaust hole 20 provided at the center of the tapered portion 16.
(A) is a bottom view, (b) is bb in (a).
It shows a cross section. The concave portion 19 has an elliptical shape (irregular shape) in plan view as shown in FIG. 2A, and is recessed stepwise from the tapered portion 16 as shown in FIG. 2B. Also, the recess 19
The exhaust hole 20 formed on the bottom surface of is rectangular as shown in FIG.

A circle 21 shown by a two-dot chain line in FIG.
Is a substantially spherical brazing material used for closing the exhaust hole 20 and shows a state before melting in the brazing chamber in the closing step of the vacuum double container 10. The brazing material 21 is made of lead-free glass.

In the step of closing the vacuum double container 10, the vacuum double container 10 before evacuation is placed on a predetermined table in a state where the bottom surface 15 of the outer bottle 12 faces upward. The supply of the brazing material 21 is performed while the table on which the plurality of vacuum double containers 10 are mounted at predetermined positions sequentially passes through the preparation chamber (low vacuum chamber), the vacuum chamber, the brazing chamber, and the cooling chamber. Then, the evacuation and sealing (melting of the brazing material 21) of the vacuum double container 10 are automatically performed. The gas contained in the metal of the inner bin 11 and the outer bin 12 is burned using the getter 22 after the closed space 14 is evacuated and sealed.
4, the degree of vacuum is increased.

The supply of the brazing material 21 is automatically performed one by one for each vacuum double container 10 by a dedicated machine. That is, when the spherical brazing material 21 falls from above the tapered portion 16 of each vacuum double container 10, the brazing material 21 naturally falls on the tapered surface of the tapered portion 16, and the brazing material 21 falls into the concave portion 19 provided at the center thereof. Will be retained.

As shown in FIG. 2B, the minor diameter d of the recess 19 is smaller than the diameter D of the brazing material 21 and the brazing material 2 before melting is formed.
1 is held in a state of floating from the bottom surface 19 a of the concave portion 19. Further, since the concave portion 19 has an irregular shape (elliptical shape) in plan view, the substantially spherical brazing material 21 does not completely block the opening of the concave portion. Therefore, the closed space 14 through the exhaust hole 20
Communication with the outside is ensured, and the exhaust of the sealed space 14 is performed smoothly.

As is clear from the above description, the concave portion 19
Is not limited to an elliptical shape as long as it is a non-circular variant shape. For example, it may be rectangular or oval. Further, the rectangular shape of the exhaust hole 20 in plan view is due to the brazing material 21 having a diameter smaller than the minor diameter d of the concave portion 19.
This is to prevent the exhaust hole 20 from being completely closed even when the air is supplied. Therefore, the shape of the exhaust hole 20 in plan view may be other than circular, and
Any shape such as a triangle or a star, not limited to a rectangle, can be adopted. A plurality of round holes may be provided close to each other. Also,
The exhaust hole 20 is not the bottom surface 19a of the recess 19 but the side surface 19b.
May be provided.

FIG. 3 shows the embodiment shown in FIG.
9 shows a modification of the cross-sectional view shown in FIG. (A) shows a first modification, (b) shows a second modification, and (c) shows a third modification. FIG. 3 shows a structure in which the brazing material 21 is held in the concave portion 19 while floating from the bottom surface 19 a of the concave portion 19.
As shown in (a), the brazing material 21 may be held in the middle of the inclined side surface 19b while entering the concave portion 19. In this case, the possibility that the brazing material 21 once held in the concave portion 19 comes off the concave portion 19 due to vibration at the time of exhaustion or the like is reduced, which is preferable. However, strict accuracy is required with respect to the processing accuracy (variation in diameter) of the brazing material 21 and the processing accuracy (variation) of the short diameter of the concave portion 19.

Further, as shown in FIG.
Is provided with a step 19c on the side surface of the bottom surface 19a so that the brazing material 21 that has entered the recess 19 is placed on the step 19c.
It is good also as a structure held in the state floated from. Alternatively, as shown in FIG. 3C, a projection 19d is provided on the bottom surface 19a of the recess 19, and the brazing material 21 that has entered the recess 19 comes into contact with the tip of the projection 19d and floats from the bottom surface 19a. It may be a structure held by. The exhaust hole 20 may be provided on the side surface 19b of the concave portion 19 as shown in FIG. 3C, or may be provided on the bottom surface 19a.

FIGS. 4A and 4B show an example of a vacuum double container according to the second embodiment, wherein FIG. 4A is a bottom view, and FIG. 4B is a side sectional view of the bottom of the outer bottle 12 with the bottom facing upward. FIG. In this embodiment, the concave portion 19 in the first embodiment is omitted, and the exhaust hole 20 is provided directly in the center (bottom) 16 a of the tapered portion 16. In this case, the substantially spherical brazing material 21 dropped and supplied from above the tapered portion 16 falls to the central portion 16a of the tapered portion 16 but is not held. Therefore, the tapered portion 1 can be easily formed due to vibration at the time of exhaust.
6 moves in the outer peripheral direction from the central portion 16a, but if the vibration stops, the central portion 16a moves along the tapered surface of the tapered portion 16.
Return to At the time of brazing, the brazing material 21 is located near the exhaust hole 20 provided in the central portion 16 a of the tapered portion 16, and the exhaust hole 20 is sealed by melting the brazing material 21.

In the example shown in FIG. 4, two exhaust holes 20 are provided in the central portion 16a of the tapered portion 16, so that the brazing material 21 before melting does not completely block the exhaust holes 20 so that the exhaust can be smoothly performed. To be done. One small hole may be provided at the center of the tapered portion 16, and one or a plurality of small holes (exhaust holes) may be provided near the small hole. Alternatively, as described in the first embodiment, only one exhaust hole having an irregular shape in plan view other than the round hole may be provided.

FIG. 5 is an enlarged view showing a concave portion 19 and an exhaust hole 20 provided at the center of the tapered portion 16 of the vacuum double container according to the third embodiment. (A) is a bottom view, and (b) shows a bb cross section in (a).
In this embodiment, the concave portion 19 has a circular shape in a plan view, and the diameter d is twice or more the diameter D of the brazing material 21. The bottom surface 19a of the concave portion 19 is formed so that the central portion protrudes, and the exhaust hole 20 is formed at the top. In this case, the brazing material 21 supplied from above the tapered portion 16 and falling into the concave portion 19 settles at a position where the exhaust hole 20 provided at the top of the bottom surface 19a of the concave portion 19 is not blocked. That is, as shown in FIGS. 5A and 5B, the substantially spherical brazing material 21 is always in contact with the side surface 19 b of the recess 19.

FIG. 6 is a bottom view showing a modification of the tapered portion 16 according to the first embodiment. (A) shows a first modification, and (b) shows a second modification. FIG. 6 (a)
In the first modified example, four projecting ridges 22 extending radially from the center to the outer periphery are formed in the tapered portion 16. Further, in the second modified example of FIG. 6B, one groove 23 extending radially from the central portion to the outer peripheral portion is formed in the tapered portion 16. In any case, the brazing material 21 that has jumped out of the concave portion 19 due to vibrations at the time of evacuation and moved to the outer peripheral portion of the tapered portion 16 is quickly moved to the central concave portion 1.
This is for returning to 9.

That is, when the brazing material 21 that has moved from the central portion to the outer peripheral portion of the tapered portion 16 due to vibration or the like at the time of exhaust returns to the central portion on the inclined surface of the tapered portion 16, it may draw a spiral depending on the vibration direction. May return. In this case, it takes time until the brazing material 21 returns to the center of the tapered portion, which is not preferable. However, as described above, if one or a plurality of grooves 23 or ridges 22 extending radially from the center to the outer periphery of the tapered portion 16 are formed, the brazing material 21 does not draw a spiral, It immediately returns to the central portion (recess 19) along 23 or ridge 22. The same effect can be obtained by combining such a groove 23 or the ridge 22 with the second or third embodiment.

In each of the above embodiments and modifications, it is preferable that the taper angle of the tapered portion 16 is larger than the maximum inclination angle when the vacuum double container 10 is inclined due to vibration during evacuation. By doing so, even if the brazing material 21 jumps out of the concave portion 19, the possibility that the brazing material 21 immediately returns to the concave portion 19 without moving to the outer peripheral portion of the tapered portion 16 is increased.

Although the embodiments and the modified examples of the present invention have been described above, the illustrated shapes are only examples. The present invention is not limited to the above embodiments and modified examples, but can be implemented in various forms. For example, in the above-described embodiments and modifications, the center of the tapered portion 16 is the lowermost portion (the lowest portion), but the lowermost portion 16a 'may be shifted from the center as shown in FIG. In this case, the exhaust hole 20 is provided not at the center but at the lowermost portion 16a '.

The substantially spherical brazing material does not need to be limited to lead-free glass, but may be made of lead-containing glass or metallic such as nickel.

[0037]

As described above, according to the present invention, in a vacuum double container having a closed space between an inner bottle and an outer bottle, a substantially spherical brazing material is used and the bottom surface of the outer bottle is used. By devising the shape of (1), it becomes possible to mechanize (automate) the brazing material setting operation in the evacuation and sealing steps of the vacuum double container.

[Brief description of the drawings]

FIGS. 1A and 1B show an example of a vacuum double container according to a first embodiment of the present invention, wherein FIG. 1A is a bottom view and FIG.

FIG. 2 is an enlarged view showing a concave portion and an exhaust hole provided at a central portion of a tapered portion in FIG. 1, wherein (a) is a bottom view,
(B) is bb sectional drawing in (a).

3A and 3B are diagrams showing a modification of the cross-sectional view shown in FIG. 2B, wherein FIG. 3A is a first modification, FIG. 3B is a second modification,
(C) shows a third modified example.

4A and 4B show an example of a vacuum double container according to a second embodiment, in which FIG. 4A is a bottom view, and FIG. 4B is a side sectional view of the bottom of the outer bottle with the bottom face up.

FIG. 5 is an enlarged view showing a concave portion and an exhaust hole provided at the center of a tapered portion of a vacuum double container according to a third embodiment, (a) is a bottom view, and (b) is (a). B) in
It is -b sectional drawing.

FIG. 6 is a bottom view showing a modified example of the tapered portion according to the first embodiment, wherein (a) shows a first modified example and (b) shows a second modified example.

7A and 7B show an example of a vacuum double container according to a modified example of FIG. 4, in which FIG. 7A is a bottom view, and FIG. 7B is a side sectional view of the bottom of the outer bottle with the bottom face up.

FIG. 8 is a side sectional view showing an example of a conventional vacuum double container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vacuum double container 11 Inner bin 12 Outer bin 14 Closed space 15 Bottom surface of outer bin 16 Tapered part 17 Wall part 18 Preliminary concave part 19 Concave part 19a Bottom of concave part 20 Exhaust hole 21 Brazing material 22 Convex part 23 Groove

Claims (8)

[Claims] 1. A vacuum double container having a sealed space between a metal inner bin and an outer bin, wherein a concave tapered portion is formed on a bottom surface of the outer bin, and a lowermost portion or a lowermost portion of the tapered portion. One or more exhaust holes communicating with the closed space are provided in the vicinity, and the exhaust holes are sealed with a substantially spherical brazing material. 2. A stepped concave portion having a stepped concave shape is formed at the lowermost portion or near the lowermost portion of the tapered portion, and the brazing material is held in the concave portion while floating from the bottom surface of the concave portion. 2. The vacuum double container according to claim 1, wherein the exhaust hole is provided on a bottom surface or a side surface of the concave portion. 3. 3. The vacuum double container according to claim 1, wherein a lowermost portion of the tapered portion is located at a central portion of the tapered portion. 4. A method according to claim 1, wherein at least one third of the length from the center to the outer periphery of the bottom surface of the outer bin is formed as the concave tapered portion, and an annular wall is formed at the outer periphery of the tapered portion. The vacuum double container according to claim 1, 2 or 3, wherein: 5. The vacuum double container according to claim 4, wherein one or a plurality of preliminary concave portions are formed on the bottom surface outside the annular wall portion. 6. The tapered portion according to claim 1, wherein one or more grooves or ridges extending radially from a central portion to an outer peripheral portion are formed.
Item 2. The vacuum double container according to item 1. 7. A method for sealing a vacuum double container having a sealed space between a metal inner bottle and an outer bottle, the method comprising: forming a concave tapered portion on the bottom surface of the outer bottle; One or more exhaust holes communicating with the sealed space are provided at the lowermost portion or near the lowermost portion, and the vacuum double container is placed on a predetermined table in a state where the vacuum double container is face down so that the bottom surface of the outer bottle is upward. The spherical brazing material is dropped from above the tapered portion, and the brazing material is naturally dropped to the lowermost portion or the vicinity of the lowermost portion of the tapered portion. After the closed space is evacuated in a vacuum chamber, the tapered portion is formed. Closing the exhaust hole by melting the brazing material located at the lowermost portion or near the lowermost portion of the vacuum container. 8. A tapered angle of the tapered portion is larger than a maximum tilt angle when the vacuum double container is tilted due to vibration at the time of evacuation of the closed space.
The method for sealing a vacuum double container as described above.