JP3692966B2 - Vacuum double container and sealing method - Google Patents

Description

[0001]
BACKGROUND 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 sealing method thereof.
[0002]
[Prior art]
Generally, a heat insulating container called a thermos bottle or a jar is composed of an inner bottle and an outer bottle manufactured by press-molding a sheet metal such as stainless steel. For example, as shown in FIG. 8, the opening edge portions 53 of the inner bottle 51 and the outer bottle 52 are welded to each other, and a sealed space 54 is formed between the inner bottle 51 and the outer bottle 52. Normally, a vacuum layer is formed between the inner bottle 51 and the outer bottle 52 by removing the air in the sealed space 54 from the exhaust hole 56 formed in the bottom surface 55 of the outer bottle 52, and a vacuum double container (heat insulation) Container) 50 is formed. Recently, even an electric pot has been commercialized that employs this type of vacuum double container as a tank and can retain heat without energization of an electric heater.
[0003]
In the evacuation and sealing process of the vacuum double container 50, the vacuum double container 50 before evacuation is placed on a predetermined table with the bottom surface 55 of the outer bottle 52 facing down. And while the stand on which the plurality of vacuum double containers 50 are placed passes through the preparation chamber (low vacuum chamber), the vacuum chamber, the brazing chamber, and the cooling chamber in order, the exhaust of each vacuum double container 50 and Sealing is performed.
[0004]
Conventionally, lead-containing glass has been used as a brazing material for sealing the exhaust hole 56 after the air in the sealed space 54 has been removed 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. Since the brazing material of lead-containing glass is manufactured by extrusion molding and cutting, it has a substantially cylindrical shape. Such a brazing material is previously placed in a recess 57 including an exhaust hole 56 formed in the bottom surface 55 of the vacuum double container 50 before exhaustion. After the vacuum double container 50 is evacuated in the vacuum chamber, the brazing material is melted in the brazing chamber and the exhaust hole 56 is sealed.
[0005]
In addition, the operation | work which puts a brazing material in the recessed part 57 of each vacuum double container 50 was performed by the manual operation using tweezers. Further, a thin piece covering the recess 57 so that the brazing material placed in the recess 57 does not jump out of the recess 57 when the vacuum double container 50 is shaken due to vibration during movement of the mounting table or during exhaustion, for example. May be welded to the bottom surface 55. In this case, an operation was performed to lift the side not welded to the bottom surface 55 of the thin plate piece and set the brazing material in the recess 57.
[0006]
[Problems to be solved by the invention]
The operation of placing the brazing material in the recess 57 in advance in the conventional vacuum double container evacuation and sealing process as described above is a manual operation, which requires man-hours and has been a barrier to cost reduction. In particular, when a thin plate piece covering the concave portion 57 is provided, the work of setting the brazing material in the concave portion 57 so as to lift one end side of the thin plate piece takes time, so improvement in workability is required. It was.
[0007]
Moreover, the lead-containing glass brazing material that has been used conventionally has disadvantages such as that lead may cause harm to the human body and that it is not easy to recycle the vacuum double container. For this reason, 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 is easily manufactured to have a substantially spherical shape by free fall. This substantially spherical brazing material has the property of easily rolling in an arbitrary direction as compared with the conventional substantially cylindrical brazing material.
[0008]
Therefore, the present invention makes it possible to mechanize the setting work of the brazing material in the exhaust and sealing process of the vacuum double container by devising the shape of the bottom surface of the outer bottle of the vacuum double container and using a substantially spherical brazing material. The purpose is to.
[0009]
[Means for Solving the Problems]
The 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, and a concave tapered portion is formed on the bottom surface of the outer bottle, One or more exhaust holes communicating with the sealed space are provided in the vicinity of the lowermost part, and the taper angle of the taper portion is larger than the maximum tilt angle when the vacuum double container tilts due to vibration during exhaust of the sealed space. The exhaust hole is sealed using a substantially spherical brazing material.
[0010]
According to such a configuration, in the exhausting and sealing process of the vacuum double container, the substantially spherical brazing material is formed from above the tapered part of the vacuum double container in a state where the bottom surface of the outer bottle is faced up. If dropped, the brazing material rolls around the tapered portion and is set in the vicinity of the exhaust hole formed in the lowermost portion of the tapered portion or in the vicinity of the lowermost portion. Even if the brazing material moves in the outer circumferential direction from the lowermost part of the taper part or near the lowermost part due to vibration during exhaust, etc., if the vibration stops, the brazing material rolls again along the inclined surface of the tapered part or Return to near the bottom. Therefore, it becomes possible to automate (mechanicalize) the setting of the brazing material without using manual work as in the prior art. In particular, since the taper angle of the taper part is larger than the maximum inclination angle when the vacuum double container is inclined due to vibration during exhaust of the sealed space, the brazing member set at or near the lowermost part of the taper part vibrates. This reduces the possibility of moving to the outer periphery of the tapered portion.
[0016]
According to the sealing method of a vacuum double container according to the present invention, 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 the taper portion One or more exhaust holes communicating with the sealed space are provided in the lowermost part or in the vicinity of the lowermost part, and the taper angle of the taper part is larger than the maximum inclination angle when the vacuum double container is inclined by vibration during exhaust of the sealed space. The vacuum double container is placed face down so that the bottom surface of the outer bottle is facing upward, and the spherical brazing material is dropped from above the tapered portion, and the brazing material is removed from the tapered portion. After naturally falling to the lowermost part or the vicinity of the lowermost part, after exhausting the sealed space in the vacuum chamber, the exhaust hole is sealed by melting the brazing material located at the lowermost part of the tapered part or near the lowermost part. To do. According to such a sealing method, it becomes possible to automate (mechanicalize) the setting of the brazing material without using manual work as in the prior art. In particular, since the taper angle of the taper part is larger than the maximum inclination angle when the vacuum double container is inclined due to vibration during exhaust of the sealed space, the brazing member set at or near the lowermost part of the taper part vibrates. This reduces the possibility of moving to the outer periphery of the tapered portion.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0019]
1A and 1B show an example of a vacuum double container according to a first embodiment of the present invention. FIG. 1A is a bottom view, and FIG. 1B is a sectional view in side view with the bottom face up. The vacuum double container 10 includes an inner bottle 11 and an outer bottle 12 manufactured by press-molding a metal plate such as stainless steel. The opening edge portions 13 of the inner bottle 11 and the outer bottle 12 are welded to each other, and a sealed space 14 is formed between the inner bottle 11 and the outer bottle 12.
[0020]
On the bottom surface 15 of the outer bottle 12, a concave tapered portion 16 having a depressed central portion is formed. In the illustrated example, the radius of the tapered portion 16 is approximately ½ of the radius of the bottom surface 15, but it 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 recessed portion 18 is formed on the outer side thereof. However, instead of providing one annular preliminary recess 18 as shown, a plurality of preliminary recesses may be arranged in an annular shape. The preliminary recess 18 has a function of holding the brazing material that has spilled from the tapered portion 16 over the annular wall portion 17. A concave portion 19 that is recessed in a step shape is formed in the central portion of the tapered portion 16, and a small hole (exhaust hole) 20 that communicates between the sealed space 14 and the outside is formed on the bottom surface thereof.
[0021]
FIG. 2 is an enlarged view showing the concave portion 19 and the exhaust hole 20 provided in the central portion of the tapered portion 16. (A) is a bottom view, (b) has shown the bb cross section in (a). As shown in FIG. 2A, the recess 19 has an elliptical shape (irregular shape) in plan view, and is recessed from the tapered portion 16 in a step shape as shown in FIG. 2B. Moreover, the exhaust hole 20 formed in the bottom face of the recessed part 19 is a rectangle as shown to Fig.2 (a).
[0022]
A circle 21 indicated by a two-dot chain line in FIG. 2B is a substantially spherical brazing material used for sealing the exhaust hole 20, and shows a state before melting in the brazing chamber in the sealing step of the vacuum double container 10. Show. The brazing material 21 is made of lead-free glass.
[0023]
In the sealing process of the vacuum double container 10, the vacuum double container 10 before evacuation is placed on a predetermined table with the bottom surface 15 of the outer bottle 12 facing down. The brazing material 21 is supplied while the stage on which the plurality of vacuum double containers 10 are placed at predetermined positions passes through the preparation chamber (low vacuum chamber), the vacuum chamber, the brazing chamber, and the cooling chamber in order. The evacuation and sealing of the vacuum double container 10 (melting of the brazing material 21) is automatically performed. The degree of vacuum in the sealed space 14 is increased by burning the gas contained in the metal of the inner bottle 11 and the outer bottle 12 using the getter 22 after exhausting and sealing the sealed space 14.
[0024]
The supply of the brazing material 21 is automatically performed for each vacuum double container 10 by a dedicated machine. That is, when the spherical brazing filler metal 21 is dropped from above the tapered portion 16 of each vacuum double container 10, the brazing filler metal 21 naturally falls on the tapered surface of the tapered portion 16, and enters the concave portion 19 provided in the central portion thereof. Retained.
[0025]
As shown in FIG. 2B, the short diameter d of the recess 19 is smaller than the diameter D of the brazing material 21, and the brazing material 21 before melting is held in a state of floating from the bottom surface 19 a of the recess 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, communication between the sealed space 14 and the outside through the exhaust hole 20 is ensured, and the sealed space 14 is smoothly exhausted.
[0026]
As is clear from the above description, the shape of the concave portion 19 in plan view may be an irregular shape that is not circular, and is not necessarily limited to an elliptical shape. For example, it may be rectangular or oval. The rectangular shape of the exhaust hole 20 in plan view is that the exhaust hole 20 may be completely blocked even if the brazing filler metal 21 having a diameter smaller than the short diameter d of the recess 19 is supplied. This is so that there is no such thing. Therefore, the shape of the exhaust hole 20 in plan view may be other than a circle, and is not limited to a rectangle, and any shape such as a triangle or a star shape can be adopted. A plurality of round holes may be provided close to each other. Further, the exhaust hole 20 may be provided on the side surface 19 b instead of the bottom surface 19 a of the recess 19.
[0027]
FIG. 3 shows a modification of the cross-sectional view shown in FIG. (A) is a first modification, (b) is a second modification, and (c) is a third modification. As a structure in which the brazing material 21 is held in the concave portion 19 in a state where it floats from the bottom surface 19a of the concave portion 19, the brazing material 21 enters the concave portion 19 while the brazing material 21 enters the concave portion 19 as shown in FIG. You may make it hold | maintain on the way. This is preferable because it is less likely that the brazing material 21 once held in the recess 19 is detached from the recess 19 due to vibration during exhaust. 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 recess 19.
[0028]
Further, as shown in FIG. 3 (b), a step portion 19c is provided on the side surface of the concave portion 19, and the brazing material 21 that has entered the concave portion 19 floats from the bottom surface 19a so as to rest on the step portion 19c. It is good also as a structure hold | maintained. 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 19a. It is good also as a structure hold | maintained by. The exhaust hole 20 may be provided in the side surface 19b of the recessed part 19 as shown in FIG.3 (c), and may be provided in the bottom face 19a.
[0029]
FIG. 4 shows an example of a vacuum double container according to the second embodiment, where (a) is a bottom view, and (b) is a cross-sectional side view of the bottom of the outer bottle 12 with the bottom face up. . In this embodiment, the concave portion 19 in the first embodiment is omitted, and the exhaust hole 20 is directly provided in the central portion (bottom portion) 16a of the tapered portion 16. In this case, the substantially spherical brazing material 21 supplied by dropping from above the tapered portion 16 falls to the central portion 16a of the tapered portion 16 but is not held. Therefore, it easily moves from the central portion 16a of the tapered portion 16 to the outer peripheral direction due to vibrations or the like during exhaust, but returns to the central portion 16a along the tapered surface of the tapered portion 16 when the vibration stops. At the time of brazing, the brazing material 21 is positioned in the vicinity of 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.
[0030]
In the example shown in FIG. 4, two exhaust holes 20 are provided in the central portion 16 a 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 is smoothly performed. I have to. 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 in the vicinity thereof. 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.
[0031]
FIG. 5 is an enlarged view showing the recess 19 and the exhaust hole 20 provided in the central portion of the tapered portion 16 of the vacuum double container according to the third embodiment. (A) is a bottom view, (b) has shown the bb cross section in (a). In this embodiment, the recess 19 has a circular shape in plan view, and the diameter d thereof is twice or more the diameter D of the brazing material 21. And the bottom face 19a of the recessed part 19 is formed so that a center part may protrude, and the exhaust hole 20 is formed in the top part. In this case, the brazing filler metal 21 supplied from above the tapered portion 16 and falling into the recess 19 settles at a position where the exhaust hole 20 provided at the top of the bottom surface 19 a of the recess 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.
[0032]
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. In the first modified example of FIG. 6A, four protruding strips 22 that extend radially from the central portion toward the outer peripheral portion 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 toward the outer peripheral portion is formed in the tapered portion 16. In either case, the brazing material 21 that has jumped out of the recess 19 due to vibration during exhaust and moved to the outer peripheral portion of the tapered portion 16 quickly returns to the recess 19 at the center.
[0033]
That is, when the brazing filler metal 21 that has moved from the central portion of the tapered portion 16 to the outer peripheral portion due to vibration during exhaust or the like returns to the central portion on the inclined surface of the tapered portion 16, the brazing material 21 returns in a spiral depending on the vibration direction. There is a case. In this case, it takes time for the brazing material 21 to return to the central portion of the tapered portion, which is not preferable. However, if one or a plurality of grooves 23 or ridges 22 extending radially from the central portion of the tapered portion 16 to the outer peripheral portion are formed as described above, the brazing material 21 does not draw a spiral, and the groove It returns to the center part (concave part 19) rapidly along 23 or the protruding item | line part 22. FIG. In addition, the same effect is acquired even if such a groove | channel 23 or the protruding item | line part 22 is combined with 2nd or 3rd embodiment.
[0034]
In each of the above embodiments and modifications, the taper angle of the taper portion 16 is preferably larger than the maximum inclination angle when the vacuum double container 10 is inclined due to vibration during exhaust. By doing this, even if the brazing material 21 jumps out of the recess 19, there is a high possibility that it will return to the recess 19 immediately without moving to the outer periphery of the tapered portion 16.
[0035]
As mentioned above, although embodiment and the modification of this invention were demonstrated, the shape shown in figure is only an example. The present invention is not limited to the above-described embodiments and modifications, and can be implemented in various forms. For example, in the above-described embodiment and modification, the central portion of the tapered portion 16 is the lowest portion (bottom portion), but the lowermost portion 16a ′ may be shifted from the central portion as shown in FIG. In this case, the exhaust hole 20 is provided in the lowermost part 16a ′ instead of the central part.
[0036]
The substantially spherical brazing material need not be limited to lead-free glass, and may be made of lead-containing glass or metallic such as nickel.
[0037]
【The invention's effect】
As described above, according to the present invention, in a vacuum double container having a sealed space between an inner bottle and an outer bottle, a substantially spherical brazing material is used and the shape of the bottom surface of the outer bottle is devised. This makes it possible to mechanize (automate) the setting work of the brazing material in the process of exhausting and sealing the vacuum double container.
[Brief description of the drawings]
1A and 1B show an example of a vacuum double container according to a first embodiment of the present invention, in which FIG. 1A is a bottom view and FIG. 1B is a sectional view in side view with the bottom face up.
2 is an enlarged view of a concave portion and an exhaust hole provided in the central portion of the tapered portion in FIG. 1, (a) is a bottom view, and (b) is a cross-sectional view taken along line bb in (a). .
3A and 3B are diagrams showing a modification of the cross-sectional view shown in FIG. 2B, where FIG. 3A is a first modification, FIG. 2B is a second modification, and FIG. 3C is a third modification. Each is shown.
FIGS. 4A and 4B show an example of a vacuum double container according to a second embodiment, wherein FIG. 4A is a bottom view, and FIG. 4B is a cross-sectional side view of an outer bottle bottom with the bottom face up.
FIGS. 5A and 5B are enlarged views showing a concave portion and an exhaust hole provided in the central portion of the tapered portion of the vacuum double container according to the third embodiment, wherein FIG. 5A is a bottom view, and FIG. It is a bb sectional view in).
6A and 6B are bottom views showing a modified example of the tapered portion according to the first embodiment, wherein FIG. 6A shows a first modified example, and FIG. 6B shows a second modified example.
7 shows an example of a vacuum double container according to a modification of FIG. 4, wherein (a) is a bottom view and (b) 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 bottle 12 Outer bottle 14 Sealed space 15 Bottom surface 16 of outer bottle Tapered part 17 Wall part 18 Preliminary recessed part 19 Recessed part 19a Recessed bottom face 20 Exhaust hole 21 Brazing material 22 Protruding part 23 Groove

Claims (2)

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 one or a plurality of exhaust holes communicating with the sealed space are provided at the lowermost portion or near the lowermost portion of the tapered portion,
The taper angle of the tapered portion is larger than the maximum inclination angle when the vacuum double container is inclined by vibration during exhaust of the sealed space,
A vacuum double container, wherein the exhaust hole is sealed using a substantially spherical brazing material. A method of sealing 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 one or a plurality of exhaust holes communicating with the sealed space are provided at a lowermost portion or near the lowermost portion of the tapered portion, and a taper angle of the tapered portion is set to Greater than the maximum tilt angle when the vacuum double container tilts due to vibration during exhaust of space;
  Place the vacuum double container face down so that the bottom surface of the outer bottle is on top,
  The spherical brazing material is dropped from above the tapered portion, and the brazing material is naturally fallen to the lowermost portion or the vicinity of the lowermost portion of the tapered portion,
  Sealing the vacuum double container characterized by sealing the exhaust hole by melting the brazing material located at the lowermost part of the tapered part or near the lowermost part after exhausting the sealed space in a vacuum chamber Method.

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