JPH0414568B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a method for manufacturing a metal thermos flask, and in particular, to a method for manufacturing a metal thermos flask, in particular, an inner container and an outer container are joined to form a double-walled container, and a space between the two containers is manufactured. The present invention relates to a method of evacuating a container through an exhaust port formed in an outer container and closing the exhaust port.

(Prior art) In recent years, metal thermos flasks have been put into practical use.This type of thermos has a double-walled structure by assembling an inner container and an outer container, and a wall is formed between the two containers in a vacuum furnace. It is produced by evacuating the space in which the gas is to be stored through an exhaust port formed in the outer container or via a tip tube connected to the exhaust port, and then closing the exhaust port or tip tube. As a means for closing the exhaust port, a method of brazing a lid is disclosed, for example, in JP-A-52-133162, JP-A-57-96622, or JP-A-58-
This is proposed in specification No. 192516. That is,
A method in which the inner container and the outer container are assembled, brazing material is filled in the parts where they are to be joined, and where the exhaust port of the outer container is to be joined with the lid, and the exhaust and brazing are performed at the same time, or the exhaust port and the lid are jointed. A method of closing the air venting gap by creating an air venting gap between the lid and melting the brazing material, or filling solid brazing material in multiple places on the surface of the lid that closes the exhaust port, and using the brazing material to connect the surface of the outer container with the soldering material. The lid is placed on the outer container with a gap between it and the lid, heated in a vacuum furnace, the wax metal is melted during exhaust, and the lid is tightly attached to the exhaust port of the outer container by its own weight to seal it. A method is proposed.

(Problems to be Solved by the Invention) In the above method, an air vent gap is provided between the exhaust port and the lid, or a gap is provided between the exhaust port and the lid using a plurality of brazing fillers placed on the underside of the disc-shaped lid. In order to exhaust the gas from the double-walled space through the gap and to melt the brazing material and close the exhaust port, a long tip tube is used, as in the case of using a tip tube. There is no problem in that the height of the thermos depends on the height of the thermos, but generally wax alloy powder is hardened with binder resin and fixed to the lid, so in order to support the lid horizontally, it is necessary to It takes skill to fix the thermos, and since the brazing material is located between the exhaust port and the lid, when the waxing material starts melting, the gas generated from the waxing material flows into the vacuum space, reducing the vacuum level of the thermos flask. There is a problem of letting it happen. Further, in the above method, only a gap small enough to be filled with the brazing material is obtained, so there is a problem that the exhaust resistance is large and the exhaust efficiency is poor. To prevent the degree of vacuum from decreasing, use a getter that adsorbs gas generated from inside the material of the container and a getter that adsorbs gas generated from the brazing metal, or use a large amount of getter that adsorbs both gases. This not only makes it extremely difficult to select a getter, but also increases the manufacturing cost of the thermos flask.

(Means for Solving the Problems) The present invention basically solves the problem in that the gas generated when a closing plate for closing an exhaust port provided in an outer container is joined to the outer container is transferred between the outer container and the inner container. In order to prevent the brazing material from flowing into the space formed between them, the brazing material is placed as far away from the exhaust port as possible, and in order to keep the exhaust port provided in the outer container almost fully open during exhaust, a blocking plate is installed. a closing portion having an area larger than the opening area of the exhaust port of the outer container; and a small brazing material support piece formed integrally with the closing portion and bent at a predetermined angle with respect to the surface of the closing portion. In this case, a closed plate is used. Specifically, the closure plate used in the present invention is such that when the brazing material is not placed on the support piece and the support piece is placed in contact with a flat surface, the closure plate will not touch the support piece and the closure part. Rotating around the connecting part, that is, the bending part, as a fulcrum,
The closed portion is made to contact a flat surface, and when the brazing material is placed, one side of the brazing material support is placed in contact with a flat surface, and this state is maintained as it is. Incidentally, as the brazing material, nickel wax, copper wax, or other commercially available materials may be used.

(Function) When the closing plate configured as described above is placed on the outer container so that the surface of the brazing material supporting piece opposite to the brazing material is in contact with the outer container, the brazing material is removed from the exhaust port. Moreover, since the closing part plays the role of shielding between the brazing material and the exhaust port, the gas released by the brazing material during melting is prevented from flowing into the space between the outer container and the inner container. Ru. Also,
When the brazing material fixed on the brazing material support piece melts and flows down to the bottom of the support piece, the weight of the closed part side is heavier than that of one side of the support piece, so the action of gravity causes the closed plate to move around the bent part as a fulcrum. rotates, the closing portion closes the exhaust port, and the melted brazing material flows by capillary action between the closing portion and the surface of the outer container, and solidifies to form an airtight seal.

(Example) In FIGS. 1 and 2 showing the manufacturing process of a metal thermos flask by the method of the present invention, 1 is a container having a double wall structure, consisting of an inner container 2 and an outer container 3, both of which are They are joined and integrated at their mouth portions 4 by welding or other means. A recess 5 is formed in the bottom 3a of the outer container, an exhaust port 6 for vacuum processing is formed in the recess 5, and a closing plate 7 is disposed near the exhaust port 6 (see FIG. 1). As shown in FIG. 2, the closing plate 7 has a substantially semicircular closing portion 7 having a size sufficient to close the exhaust port 6.
a, and a brazing material support piece 7b formed integrally with the closure part, the brazing material support piece 7b being bent at a certain angle with respect to the surface of the closure part, and its free end facing the closure part. Projection 7c facing the plane including the surface
is formed, and a brazing material 8 is fixed on the opposite surface. When the closing plate 7 is placed as shown in FIG. 1a without the brazing material, the weight from the bending part 7d to the closing part is heavier than the weight of the brazing material supporting piece alone, so the plate 7 is placed with the bending part 7d as a fulcrum. It rotates in the direction of arrow A in Figure 1a, and stabilizes with the lower surface of the closure part in contact with a flat surface, similar to the state shown in Figure 1b. In the present invention, in order to prevent the closing plate 7 from blocking the exhaust port 6 during vacuum processing, the amount of the brazing material 8 is adjusted such that the brazing material 8 is heavy on one side supporting the brazing material 8 and the brazing material 8 is heavy on one side. It is set to be stable in the state shown in Figure 1a.

When performing vacuum treatment on a double-walled container using the closing plate 7 having the above structure, first, as shown in FIG. 5, a closing plate is placed in the vicinity of the exhaust port 6, with its bent portion 7b and the projection 7c of the brazing material support piece in contact with the surface 5a of the recess 5. Place it in a vacuum heating furnace as it is, and heat it to 10 ^-2 at a temperature below the melting point of the brazing material 8, for example 400°C, while heating and exhausting.
Evacuate to a vacuum level of ~10 ^-4 Torr and remove the inner container 2.
The space 10 between the outer container 3 and the outer container 3 is evacuated, and then the vicinity of the brazing material 8 is heated to a temperature equal to or higher than the melting point of the brazing material 8 by high-frequency heating, radiation heating, or the like. When the brazing material 8 is heated to a temperature above its melting point, it melts and flows down below the brazing material support piece 7b, and as a result, the side of the brazing material support piece 7b becomes lighter than the side of the closing part, so the closing plate 7 Using the bent portion 7d as a fulcrum, it rotates counterclockwise as shown by arrow A in FIG. 1a, resulting in the state shown in FIG. 1b. At this time, the melted brazing material 8 enters between the closing portion 7a and the surface of the recess due to capillary action, so the closing plate 7 is brazed, and when the outer container is cooled, the exhaust port of the outer container is sealed by the closing plate 7. and a metal thermos flask is obtained.

In addition, in the embodiment, the surface 5 around the exhaust port 6
A is slightly recessed from the bottom surface 3a of the double-walled container, and a recess 5 is formed so that the area around the exhaust port 6 is deeper than the other surfaces, but it is not necessarily necessary to provide the recess 5. The bottom surface may be flat or beveled as shown in FIGS. 3 and 4. Further, although a closing plate 7 consisting of a semicircular closing portion 7a and an L-shaped brazing material support piece 7b was used, it was difficult to set the position of the closing plate 7 at a predetermined position. As shown in the figure, the occlusion plate 7
The protrusion 11 may be provided on the wall surface of the recess 5, and a recess 12 protruding in the radial direction may be provided on the wall surface of the recess 5 to regulate the positional relationship between the closing plate 7 and the exhaust port 6. Further, on the contrary, a convex portion projecting inward may be provided on the wall surface of the recess 5, and a concave portion may be provided on the closing plate 7. Furthermore, as shown in FIG. 4, a protrusion 13 may be provided on the surface of the recess 5, and the protrusion 11 may be engaged with the protrusion 13, thereby regulating the position of the closing plate 7.

Further, as shown in FIGS. 3 and 4, a wall 14 or a recess for holding the brazing material 8 is provided on the brazing material support piece 7b, and the melted brazing material 8 is prevented from staying on the brazing material supporting piece. For this purpose, a notch or an opening 15 may be provided in the support piece. Furthermore, in order to allow the blocking plate 7 to easily rotate and close the exhaust port 6 when the brazing material 8 melts, a protrusion 7d is provided on the lower side of the free end of the support piece, so that when the brazing material 8 is placed on it, a protrusion 7d is provided on the lower side of the free end of the support piece. Alternatively, the contact area of the support piece 7b may be made as small as possible to prevent the support piece 7b from adhering to the melted brazing material.

(Effects of the Invention) As is clear from the above description, according to the present invention, the brazing material 8 only needs to be placed in one place, and the size (especially height) of the brazing material 8 does not require precision. This makes the work much easier. Since the place where the brazing material 8 melts can be located away from the exhaust port, a large amount of occluded gas in the brazing material 8 generated immediately after melting almost never flows into the space between the inner container and the outer container. Therefore, the amount of getter used can be reduced. Furthermore, since the gas stored in the brazing material 8 does not flow into the space, excellent effects such as ease of getter selection can be obtained.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the manufacturing process of a metal thermos flask according to the method of the present invention, FIG. 2 is an exploded perspective view of essential parts of the metal thermos flask, and FIGS. It is an exploded perspective view of the main part of a metal thermos flask. DESCRIPTION OF SYMBOLS 1 - double wall structure container, 2 - inner container, 3 - outer container, 4 - mouth, 5 - recess, 6 - exhaust port, 7 - closing plate, 7a - closing part, 7b - brazing material support piece, 7d
~Bending portion, 8~Brazing material, 10~Space, 11~Protrusion, 12~Recess, 13~Protrusion, 14~Wall, 15~
Opening.

Claims (1)

[Claims] 1. A method for manufacturing a metal thermos flask, which has a double wall structure consisting of an inner metal container and an outer container, and vacuum insulates the space formed between the two containers,
An outer container and an inner container having an exhaust port are joined to form a double-walled container, and the space between the two containers is evacuated in a vacuum heating furnace, and the exhaust port of the outer container is sealed with a closing plate. In order to stop the outer container, a closing portion having an area larger than the opening area of the exhaust port of the outer container, and a small-sized brazing material support piece formed integrally with the closing portion and bent at a predetermined angle with respect to the surface thereof. The brazing material is placed on the brazing material support piece, and a blocking plate is used, with one side of the support being heavier than the blocking side. Place it in contact with a nearby surface,
After the closing plate is placed on the outer container in a vacuum heating furnace at a temperature below the melting point of the brazing material, the closing plate is rotated about its bent portion as a fulcrum by melting the brazing material, and the closing plate is heated at the closing portion. A method for manufacturing a metal thermos flask, characterized in that the exhaust port is closed, and a surface near the exhaust port and a closing plate are bonded and sealed using melted brazing material. 2. The method according to claim 1, wherein the exhaust port is formed in a recess formed in the bottom wall of the outer container, and the vacuum treatment is performed by placing the closing plate on the surface of the recess. 3. The method of manufacturing a metal thermos flask according to claim 2, wherein the surface of the recess is inclined with respect to the bottom surface of the outer container. 4. Vacuum processing is performed by using a closing plate having a protrusion near the bent portion and engaging the protrusion with a recess or protrusion provided on the bottom wall of the outer container. Method described. 5. A closing plate having a side wall or a recess for holding the brazing material on the brazing material support piece, and a notch or an opening for allowing the melted brazing material to flow down to the lower side of the brazing material support piece. A method according to any one of claims 1 to 3 for use. 6. The method according to any one of claims 1 to 4, which uses a closing plate in which a protrusion that contacts the surface of the outer container is formed on the free end of the brazing material support piece.