JP2774023B2 - Vacuum insulated container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum heat insulating container provided with a vacuum heat insulating space between an outer container and an inner container, and more particularly to a vacuum heat insulating container used for high temperature applications.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, an outer container 12, an inner container 14 having a vacuum insulating space 13 provided between the outer container 12, and a vacuum insulating space, as shown in FIG. 13 is known, comprising a membrane member 15 for closing the opening of the thirteenth opening. Furthermore, the inner container 14
Is composed of a main body 16 made of a thick metal material and an opening 17 made of a thin metal material.
The membrane member 15 made of a thin metal material.
At the same time, it has been considered to reduce the heat conduction, suppress the heat bridge effect, and improve the heat insulation performance.

[0003] Further, in order to withstand the weight of the contents and the atmospheric pressure, it is general to appropriately arrange a spacer in the vacuum heat insulating space 13. As the spacer, as shown in FIG. 4 (a), one filled with powder 18 without gaps, as shown in FIG. 4 (b), one filled with fibers 19 without gaps, and as shown in FIG. Some of them are partially arranged.

Further, when the inside of such a vacuum insulated container is heated to a high temperature, the members constituting the inner container 14 tend to expand. However, since the free expansion is suppressed by the spacer, excessive thermal stress is generated in the opening 17 and the membrane member 15 continuous therewith, and when used repeatedly, the metal material is damaged and vacuum breakage is caused. There's a problem. Therefore, as means for reducing thermal stress, it is known to provide a membrane member 15 with a telescopic mechanism 20 such as a bellows structure as shown in FIG.

[0005] The metal material forming the inner container 14 is as follows.
Generally low thermal conductivity, good weldability,
Austenitic stainless steel (especially SUS304 is common) due to its excellent heat and corrosion resistance
Is used.

[0006]

By the way, the welded portion of the metal material constituting the vacuum insulated container needs the whole line hermetic welding. However, when the container size is increased, the membrane member 15 having the above-described expansion and contraction mechanism 20 is required. Is a complicated welded structure, and it is necessary to use a thin metal material to reduce heat conduction, so it is difficult to obtain stable welding quality, and it is extremely difficult to automate welding. there were.

The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a vacuum insulated container having stable welding quality and capable of automating welding.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to a vacuum insulated container having an outer container and an inner container provided with a vacuum insulated space between the outer container. The main body and the thin opening are joined together, and the main body is made of high-purity ferritic stainless steel, and the opening is made of austenitic stainless steel.

[0009]

According to the present invention, since the main body of the inner container is made of a high-purity ferritic stainless steel having a small linear expansion coefficient, thermal expansion and contraction is reduced and thermal stress can be reduced, and the opening is made of a heat conductive material. Since it is made of austenitic stainless steel having a low rate, the heat insulating performance does not decrease. In order to reduce the thermal stress as described above,
This eliminates the need for the membrane member to be a complicated welded structure having a telescopic mechanism and the like, stabilizes welding quality, and can automate welding.

[0010]

An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, 1 is a vacuum insulated container,
It comprises an outer container 2 and an inner container 4 provided with a vacuum heat insulating space 3 provided between the outer container 2. The vacuum insulation space 3 is evacuated after being filled with the powder-based filler 10 as a spacer. Note that a fiber-based filler may be used as the spacer, and in that case, the spacer may be partially arranged as shown in FIG.

The inner container 4 has a main body 5 made of high-purity ferritic stainless steel having a thickness of 1.5 to 3.0 mm to secure necessary strength, and a main body 5 to reduce heat conduction. An opening 6 made of a thin austenitic stainless steel having a thickness of 1.0 mm or less is formed, and an upper end of the main body 5 and a lower end of the opening 6 are welded. In addition, inner container 4
The upper end of the opening 6 and the upper end of the outer container 2 are connected by a membrane member 7 made of a thin austenitic stainless steel having a thickness of 1.0 mm or less in order to reduce heat conduction. Three openings are closed.

Next, the operation of the above configuration will be described.
Table 1 shows the linear expansion coefficient and the thermal conductivity of the high-purity ferritic stainless steel forming the main body 5 of the inner container 4 and the austenitic stainless steel forming the opening 6 and the membrane member 7.

[0013]

[Table 1]

In this embodiment, since the main body 5 of the inner container 4 is made of high-purity ferritic stainless steel, the elongation can be suppressed to about 60% as compared with the conventional austenitic stainless steel. Therefore, the thermal stress generated in the opening 6 of the inner container 4 and the membrane member 7 connected to the opening 6 is reduced, and it is not necessary to adopt a structure such as a bellows structure for the membrane member 7.

On the other hand, if the entire inner container 4 is made of a high-purity ferritic stainless steel, the heat conductivity is about 1.5 times larger than that of the austenitic stainless steel. In this embodiment, since the opening 6 of the inner container 4 is made of austenitic stainless steel, the heat insulating performance does not deteriorate.

Next, a specific embodiment will be described. Table 2
Using the materials A to E shown in (1) for the main body 5 of the inner container 4, the vacuum insulated containers 1 shown in FIG. The planar shape of the inner space of the inner container 4 is a square with a side length L of 400 mm, the depth H of the main body 5 is 1000 mm, and the depth h of the opening 6 is 100 mm. The thickness T of the main body 5 is 3.0 m.
m, the thickness t of the opening 6 and the membrane member 7 is 1.0 mm
It is. The opening 6 and the membrane member 7 are made of austenitic stainless steel SUS304, and the vacuum heat insulating space 3 is filled with a fibrous filler 11.

[0017]

[Table 2]

In Table 2, A is an austenitic stainless steel SUS304 (the same as a conventional example as a comparative example), and BE is a high-purity ferritic stainless steel.
As shown in FIG. 2A, a lid 8 is attached to each of the vacuum insulation containers 1 thus manufactured, and the inside of the
2C, a strain gauge was attached to the corner of the membrane member 7 indicated by a circle P in FIG. 2B, and thermal strain was measured.

As a result, in the vacuum insulated container 1 in which A is used as the main body 5 of the inner container 4, the thermal distortion is 7000 to 8000.
In contrast to the case of using μm, those using B to E were all 2000 to 2500 μm, which proved that the membrane member 7 did not require a stretching mechanism such as a bellows structure. Note that the amount of heat dissipated in each of the manufactured vacuum insulated containers 1 was the same.

In the case of 0.03% <C, like a general ferritic stainless steel, a part of the weld metal and the heat-affected zone have a martensitic structure, which is not suitable for a vacuum insulation container. In addition, even if the steel content is 0.03 ≧ C, the steel type that does not contain Ti and Nb cannot suppress the influence of C introduced as an impurity during welding, and partially forms a martensitic structure. In addition to the unstable quality, the crystal grains are remarkably coarsened, causing a problem in strength. Further, ferritic stainless steel has a problem of low-temperature brittleness, and therefore cannot be applied to a vacuum insulated container for low-temperature use.

[0021]

According to the present invention, since the main body of the inner container is made of a high-purity ferritic stainless steel having a small linear expansion coefficient as described above, thermal expansion and contraction is reduced, and thermal stress can be reduced. Therefore, there is no need to make the membrane member a complicated welded structure having a telescopic mechanism and the like, and the welding quality is stabilized, and the welding can be automated to improve the productivity.
In addition, the simpler shape of the membrane member reduces material costs, facilitates connection with the lid, and reduces the heat insulation performance because the opening is made of austenitic stainless steel with low thermal conductivity. It has a great effect, for example, there is no.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a vacuum insulated container according to one embodiment of the present invention.

FIG. 2 shows a test state of the vacuum insulated container of the embodiment,
(A) is a longitudinal sectional view, (b) is an explanatory view of an arrangement position of a strain gauge.

FIG. 3 is a longitudinal sectional view showing a schematic configuration of a conventional vacuum insulated container.

FIG. 4 is a longitudinal sectional view of a main part showing each example of a spacer arranged in a vacuum heat insulating space in a conventional vacuum heat insulating container.

FIG. 5 is a longitudinal sectional view showing one structural example of a membrane member in a conventional vacuum insulated container.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vacuum heat insulation container 2 Outer container 3 Vacuum heat insulation space 4 Inner container 5 Main body 6 Opening

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Yamazaki 2-26, Ohama-cho, Amagasaki City, Hyogo Prefecture Inside the Kubota Mukogawa Works Co., Ltd. -12680 (JP, Y2) (58) Field surveyed (Int. Cl. ⁶ , DB name) B65D 81/38

Claims (1)

(57) [Claims] 1. A vacuum insulated container provided with an outer container and an inner container provided with a vacuum insulated space between the outer container, wherein the inner container has a thick body portion and a thin opening portion. Wherein the main body is made of high-purity ferritic stainless steel and the opening is made of austenitic stainless steel.