JPS63302814A - Method for sealing metal thermos - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vacuum sealing method for a vacuum double-walled thermos flask consisting of a metal inner bottle and a metal outer bottle.

An inner bottle and an outer bottle made of stainless steel are joined at the mouth,
Metal thermos flasks are known that have a double-layer vacuum structure by evacuating the inner and outer bottles through an exhaust hole provided at the bottom of the outer bottle, and then sealing the exhaust port. There was a problem in that it was difficult to seal the exhaust hole at times.

As a method of sealing the υ1 pores, the vacuum is drawn under heating through a tube-shaped vacuum tip (chip) provided in advance at the bottom of the outer bottle, and then the vacuum [1 is sealed and the tip is cut and removed. An opening that serves as an exhaust hole is provided at the bottom of the outer bottle, and a lid made of a metal plate is placed around the periphery of the opening to support the opening so that a gap for exhaust is formed. A method has been adopted in which a lid is placed in a vacuum heating furnace, heated and evacuated, and at the same time a brazing material is melted and a lid is soldered to the periphery of the opening.

However, the former method requires three steps: vacuum heating treatment for degassing the metal material, vacuum evacuation treatment between the inner and outer bottles, and sealing, making it inefficient and expensive to manufacture.
It had become. In addition, the latter method allows vacuum heating of the metal material, vacuum evacuation between the inner and outer bottles, and sealing at the same time, but in order to properly support the lid for closing the exhaust hole and to seal completely, it is necessary to It is necessary to distribute a small amount of solid brazing filler metal in multiple locations in a narrow space, and in order to increase the conductance for ventilation, the filler filler metal used to support the lid needs to be thinner and taller, so it is difficult to prepare for the preparation work. It took a lot of effort and was not practical.

The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a method for sealing a metal thermos flask, which makes it easy to seal the exhaust hole for evacuation.

That is, the method for sealing a metal thermos according to the present invention is as follows:
A method for vacuum-sealing the gap between the inner bottle and the outer bottle of a metal thermos flask, the exhaust opening in the gap between the inner bottle and the outer bottle being covered with a wire mesh, and a brazing material placed on the wire mesh. While vacuuming in a vacuum heating furnace, the brazing filler metal is heated and melted.
It is characterized in that the molten brazing filler metal closes the openings of the wire mesh. Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a cross-sectional view of an example of a metal thermos obtained by the present invention, and FIG. 2 is a perspective view thereof. Moreover, FIGS. 3 and 4 are explanatory diagrams of the manufacturing method. This metal thermos! consists of an inner bottle 2 and an outer bottle 3 made of metal. Inner bottle 2
and the outer bottle 3 are welded together at the mouth 5, and a space 6 is formed between them at a portion other than the joint. A circular recess 7 is formed at the bottom of the outer bottle 3, and an exhaust hole 8 for evacuation is formed in the center thereof as an opening. This exhaust hole 8 is sealed by a lid member 9 that is soldered to a peripheral edge 7a formed in the shape of an inward flange at the bottom of the recess 7.

The lid 9 is mainly made of a metal mesh 10 made by knitting metal wires, and the mesh 10a is closed with a layer of brazing material 11 used for soldering the lid 9. As the metal mesh for forming the lid material, for example, a braided stainless steel wire with a wire diameter of 0.2 mm can be used. The coarseness of the metal mesh is preferably about 30 to 50 meshes, but is not limited to this. For example, relatively coarse nets of about 20 meshes may be used in a double layer.

The aperture ratio of the metal mesh IO is preferably about 40 to 60%. Note that if a metal plate having an outer diameter larger than the diameter of the exhaust port 8 is placed over the metal mesh 1O and simultaneously integrated with the metal plate by soldering, the strength and sealing performance of the sealing portion can be further improved.

Next, to explain the manufacturing method of this thermos bottle, first, the inner bottle 2 and outer bottle 3 are welded together at the mouth part 5 and then turned upside down. A metal net IO is placed so as to cover it. The metal mesh 10 is formed into a circular shape to match the shape of the recess 7, and is placed on the flange-like peripheral edge 7a of the recess. As shown in Figs. 3 and 4, solid brazing filler metal is placed on this metal mesh IO! ! , and place it in a vacuum heating furnace to perform evacuation and heating. By this vacuum heating, the gas in the metal material is released, and the space 6 between the inner and outer bottles is evacuated. When the heating temperature is maintained above the melting temperature of the brazing filler metal 1 with sufficient evacuation, the brazing filler metal 11 scattered on the metal net melts and diffuses, forming the mesh 10a of the metal net IO.
At the same time, a metal mesh IO is joined to the peripheral edge of the opening. As a result, the exhaust hole 8 after evacuation is completely sealed, and a thermos flask with excellent heat insulation properties can be obtained. As the brazing material 11, for example, a nickel brazing material containing chromium, boron, silicon, etc. can be used. The brazing material can be formed into a rod, plate, or other suitable shape, or in the form of granules. The size and shape of the exhaust 118 may be optimally selected by considering the shape and dimensions of the entire thermos flask. In the illustrated example, the exhaust hole 8 is provided in a recess 7 provided at the bottom of the outer bottle, but it may be provided directly in the bottom of the outer bottle without providing such a recess.

This method of sealing a thermos flask is to seal the exhaust hole for vacuum evacuation by covering the exhaust hole 8 with a metal net 10, placing a brazing material 11 on top of the metal net 10, and performing vacuum heating in a vacuum heating furnace. Therefore, the setting of the metal mesh and the brazing material is easy, and the preparation work for sealing is simple. Since the metal mesh 10 generally has a high aperture ratio, the conductance during evacuation is large, and since vacuum heating and sealing can be performed in the same cycle, the entire sealing operation can be performed extremely efficiently and easily. I can now do it.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an example of a metal thermos obtained by the present invention, FIG. 2 is a perspective view thereof, and FIGS. 3 and 4 are illustrations of the manufacturing method.

Claims (1)

[Claims] (1) A method of vacuum sealing the space between the inner bottle and the outer bottle of a vacuum double-bottle type metal thermos flask, the method comprising: covering the exhaust opening between the inner bottle and the outer bottle with a wire mesh; A metal thermos flask characterized by heating and melting the brazing material while applying a vacuum in a vacuum heating furnace with the brazing material placed on the wire mesh, and closing the openings of the wire mesh with the melted brazing material. Sealing method.