JPH0510494A - End portion structure of vacuum insulation box - Google Patents

Abstract

PURPOSE:To provide the end portion structure of a vacuum insulation box improved in its durability to repetitive thermal stress. CONSTITUTION:A curved portion 19 for absorbing thermal deformation of an inner box 11 and a stopper 20 for limiting the deformation of the curved portion within a fixed range are provided in a portion of the inner box 11 in the vicinity of the membrane 15 of a vacuum insulation box. Though the thermal deformation of the inner box 11 is absorbed by the curved portion 19, the deformation of the curved portion 19 is limited within a fixed range thereby by the stopper 20 and the stress of the membrane 15 is uniformalized by further thermal deformation to be reduced so as to improve the durability of the vacuum insulation box.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an end structure of a vacuum insulation box body, and more particularly to an end structure of a vacuum insulation box body suitable for accommodating a hot object.

[0002]

2. Description of the Related Art A conventional vacuum heat-insulating box body, for example, as shown in FIG. 8, forms a double-walled box body having an opening 13 in one side by an inner box 11 and an outer box 12. A vacuum heat insulating layer (14) is formed between the outer box (12) and the outer box (12), and a peripheral wall (16) of the inner box (11) and the outer box (12) are connected by a membrane (15) that seals the vacuum heat insulating layer (14). Then, by using the flange 17 provided on the peripheral edge of the outer box 12 on the opening side, the heat insulating lid 18 is covered.

However, when a high-temperature object is accommodated in the vacuum insulation box body shown in FIG. 8, the inner box 11 rises in temperature and expands toward the membrane by a length ΔS, as shown in FIG. In the partial structure, the deformation concentrates on the membrane 15. for that reason,
The stress generated in the membrane 15 becomes the largest, and the inner box 11
Repeated heating and cooling of the membrane may damage the membrane 15 first, and the life of the vacuum insulation box will be
There is a problem that it is decided by.

For this reason, conventionally, as shown in FIG.
There has been proposed a vacuum insulation box body having a curved portion 19 that absorbs the thermal deformation of the. The curved portion 19 has a semicircular cross-sectional shape.

[0005]

In the vacuum heat insulating box body shown in FIG. 10, since the curved portion 19 absorbs the thermal deformation of the inner box 11, the stress generated in the membrane 15 is reduced, but the curved portion is opposite. There is a problem that a large stress is generated by 19. This is because in order to facilitate the processing of the curved portion 19,
This is remarkable when the length of the curved portion 19 is equal to or shorter than that of the membrane 15.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and provide an end structure of a vacuum heat insulating box which can surely suppress the generation of stress.

[0007]

In order to achieve the above object, the present invention forms a double-walled box body having an opening in one side by an inner box and an outer box, and between the inner box and the outer box. A vacuum heat insulating layer is formed in the vacuum heat insulating box body in which the peripheral edges of the inner box and the outer box on the opening side are connected by a membrane that seals the vacuum heat insulating layer, in the inner box portion in the vicinity of the membrane,
A bending portion that absorbs thermal deformation of the inner box and a member that limits the deformation of the bending portion within a certain range are provided.

[0008]

According to the above construction, when the inner box is thermally deformed toward the membrane side, the curved portion absorbs a part of the thermal deformation.
At this time, the member that restricts the deformation limits the deformation of the bending portion to a certain range, and averages and reduces the stress generated in the bending portion and the membrane. Therefore, it is possible to prevent the actual situation that the stress of the curved portion or the membrane becomes excessive and the life of the vacuum insulation box body is shortened.

[0009]

【Example】

Example 1 As shown in FIGS. 1 and 2, a curved portion 19 for absorbing thermal deformation of the inner box 11 is provided in a portion of the end wall 16 of the inner box 11 near the membrane 15. Is formed over the entire length of the inner circumference of. Further, the bending portion 19 has a stopper 20 for limiting the deformation of the bending portion 19 within a certain range ΔL.
Is provided.

The curved portion 19 has a semicircular cross section, and the stopper 20 has a restraining plate 21 having a convex cross section and a guide plate 22 having a Z-shaped cross section. This restraint plate 21,
The protrusion 23 at the center is installed so as to fit into the inside of the curved portion 19, and the rear edge of the protrusion 23 is fixed to the end wall 16, and the front side portion of the protrusion 23 and the curved portion 19 are kept at room temperature. It is configured such that a gap ΔL exists between the front side end portion. The front edge of the restraint plate 21 is slidably inserted into a guide plate 22 fixed to the end wall 16.

The stopper 20 may be provided over the entire length of the curved portion 19 in the inner circumferential direction, but since it becomes a heat bridge, it is provided at a plurality of locations in the inner circumferential direction when heat insulation performance is strongly required. Each may be partially installed.

When a high-temperature object is accommodated in the vacuum insulation box body having such a structure, the inner box 11 rises in temperature and expands toward the membrane 15. At that time, first, the curved portion 19 is deformed to absorb the thermal expansion of the inner box 11. When the inner box 11 is deformed to a certain extent or more, the gap ΔL is clogged, and the protrusion 23 is curved.
Hit the front side of. After this time, the bending portion 19 is prevented from being deformed, the expansion force of the inner box 11 is transmitted to the membrane 15 via the protrusion 23, and the membrane 15 is deformed.

As described above, the thermal expansion of the inner box 11 has a length ΔL.
The amount is absorbed by the deformation of the curved portion 19, and the remaining length ΔM appears as the deformation of the membrane 15. That is, the deformation of the curved portion 19 corresponding to the length of ΔL and the deformation of the membrane 15 corresponding to ΔM are balanced, and the stresses generated in the curved portion 19 and the membrane 15 are averaged and reduced. As a result, it is possible to prevent the stress of the curved portion 19 and the membrane 15 from becoming excessive and the life of the vacuum heat insulating box from being shortened.

Table 1 shows the results of stress analysis by the finite element method for the two-dimensional model shown in FIG. here,
The model in Fig. 3 (a) does not have a curved portion and has a length A
= 250 mm, width B = 60 mm, plate thickness t = 1 mm of the inner box 11 and the membrane 15 and plate thickness T = 3 mm of the outer box 12, and a forced displacement δ = 6 mm is given to the base end of the inner box 11. The model of FIG. 3 (b) has a semicircular curved portion 19 with a radius R = 20 mm formed in the inner box 11 at a position C = 125 mm away from the membrane 15 of the model of FIG. 3 (a). .. The model in Fig. 3 (c) is
In the model (b), the curved portion is provided with a stopper, and the deformation amount λ of the curved portion 19 is limited to 2.5 mm. Also, Table 1
The numerical values shown in are the ratios when the stress intensity (= maximum principal stress−minimum principal stress = maximum shear stress × 2) occurring in the model of FIG.

[0015]

From Table 1, it is understood that the model of FIG. 3 (c), that is, the model of the present invention has the most durability. Embodiment 2 As shown in FIG. 4, a plurality of curved portions 19 and stoppers 20 in Embodiment 1 are provided. The stress generated in the curved portion 19 and the membrane 15 is smaller than that in the first embodiment. Third Embodiment The sectional shape of the curved portion 19 in the first embodiment is not limited to a semicircle, and a square as shown in FIG. 5 or another shape can be selected. Example 4 As shown in FIG. 6, the membrane 15 has a three-layer bellows structure. With such a structure, the membrane 15
Since the allowable deformation amount of
And the stress generated in the membrane 15 is much smaller than that in the first embodiment. Embodiment 5 As shown in FIG. 7, the stopper 20 in Embodiment 1 is provided at the corner portion of the box body where the stress is most concentrated. With such a configuration, the stopper 20 reduces the heat bridge and improves the heat insulating performance.

[0017]

As described above, according to the present invention, when the inner box is thermally deformed, the curved portion absorbs a part of the deformation and the remaining portion deforms the membrane. Moreover, at that time, the stopper limits the deformation of the bending portion to a certain range, and the deformation of the bending portion and the deformation of the membrane are balanced. Therefore, the stress generated in the curved portion and the membrane can be averaged and reduced, and the durability of the vacuum insulation box body against the thermal stress due to repeated heating and cooling of the inner box can be significantly improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a vacuum heat insulating box body according to a first embodiment of the present invention.

2 is a cross-sectional view of a main part showing an end structure of the vacuum heat insulating box body of FIG.

FIG. 3 is an explanatory diagram of a two-dimensional model when a stress analysis is performed by a finite element method on the end structure of the vacuum heat insulating box.

FIG. 4 is a cross-sectional view of essential parts showing an end structure of a vacuum heat insulating box according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of a main part showing an end structure of a vacuum heat insulating box according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a main part showing an end structure of a vacuum heat insulating box according to a fourth embodiment of the present invention.

FIG. 7 is a perspective view of a vacuum heat insulating box body according to a fifth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing an example of a conventional vacuum insulation box body.

9 is a cross-sectional view of a main part showing an end structure of the vacuum heat insulating box body shown in FIG.

FIG. 10 is a cross-sectional view showing another example of the end structure of the conventional vacuum heat insulating box.

[Explanation of symbols]

 11 Inner box 12 Outer box 13 Opening 14 Vacuum insulation layer 15 Membrane 19 Curved part 20 Stopper

Claims (1)

Claim: What is claimed is: 1. A double-walled box body having an opening on one side is formed by an inner box and an outer box, and a vacuum heat insulating layer is formed between the inner box and the outer box. In a vacuum heat-insulating box body in which the opening-side peripheral edges of the inner box and the outer box are connected by a membrane that seals the vacuum heat-insulating layer, the inner box portion near the membrane has a curvature that absorbs thermal deformation of the inner box. An end structure of a vacuum heat-insulating box body, comprising: a portion and a member that limits deformation of the curved portion within a certain range.