JPH05248593A - Welded part structure of vacuum insulation body - Google Patents

Abstract

PURPOSE:To enable prevention of welding defects and oxidation without enlarging a welded structure, and provide the welded structure of a vacuum insulation body where the degree of vacuum is not reduced for a long period of time. CONSTITUTION:An external wall 1 is formed by a plurality of divided metal plates 3, 4, and after a heat insulating material 6 is filled and before the welding is implemented between the divided metal plates 3, 4, a thin-walled metal plate 7 which is tightly fitted to the divided metal plates 3, 4 is arranged on the rear side of the welded part and along the whole length of the welding. This arrangement prevents the inclusion of the heat insulating material by the thin- walled metal plate, and also prevents the dissolution and inclusion of the heat insulating material in the molten metal at the welded part, and the generation of the welding defects due to leaking. The external surface of the thin-walled metal plate 7 is tightly fitted to the internal surface of the divided metal plates 3, 4, and the air volume in the clearance can be extremely reduced, supplement of the air during the welding can be prevented, and the oxidation of the bead on the rear side of the welded part can be extremely reduced, forming a welding joint of sufficient strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welded structure of a vacuum heat insulating material such as a vacuum heat insulating container in which a heat insulating material is filled between an inner wall and an outer wall made of a metal plate and which is held in vacuum.

[0002]

2. Description of the Related Art Conventionally, as this type of vacuum heat insulator, for example, structures shown in FIGS. 9 and 10 have been provided. That is, as shown in FIG. 9, the outer wall 20 made of a metal plate has an open portion.
It is formed by a main body 22 having 21 and a lid 23 that is welded to the main body 22 after closing the open portion 21, and through the open portion 21, inside the main body 22, an inner wall 24 made of a metal plate is arranged and heat insulation is performed. Inorganic fiber 25, which is a material, is filled as a spacer. Then, as shown in FIG.
In this state, the lid 23 is welded 26 to the main body 22 in the closed state and the inside is made into a vacuum layer by evacuation.

[0003]

However, according to the above-mentioned conventional structure, when the lid body 23 is welded 26 to the main body 22, the inorganic fiber 25 is caught in the welded portion, so that the molten metal in the welded portion is caught. The inorganic fibers 25 will be dissolved and intervened. Then, as shown in FIG. 11, the inorganic fiber 25 melts into the welded portion to cause a welding defect such as generation of a pinhole 27, and further, a binder such as a phenol resin contained in the inorganic fiber 25 is heated by welding heat. Gasification,
Weld defects such as the generation of blowholes (gas pools) 28 are generated, and the degree of vacuum is lowered due to the occurrence of leaks such as the pinhole 27 and blowhole 28.

Further, since it is a welded portion where it is difficult to shield the back gas such as argon, the back side (back bead) of the welded portion is oxidized as shown in FIG. 12, and a welding defect such as a notch 29 occurs. It was a problem in terms of strength.

To address this, for example, as shown in FIG. 13, a welded joint portion 23A extending outward from the edge portion of the lid 23 is integrally provided, and the lid 23 is fitted into the main body 22. After that, it is conceivable to weld 26 between the outer edges of the welded joint portion 23A and the main body 22. However, according to this welded structure, the welded joint 23A
The outer dimension of the vacuum heat insulating body increases in accordance with the protrusion dimension X, and the overall size is increased.

An object of the present invention is to provide a welded structure of a vacuum heat insulating body capable of preventing welding defects and preventing oxidation without increasing the size of the whole.

[0007]

In order to achieve the above object, the welded structure of the vacuum heat insulating body of the present invention has an outer wall formed of a plurality of divided metal plates, filled with a heat insulating material, and then separated between the divided metal plates. Before welding, a thin metal plate that is in close contact with both the divided metal plates is arranged on the back side of the welded portion between the divided metal plates and over the entire length of the welding line.

[0008]

According to the structure of the present invention, after the heat insulating material is filled, the thin metal plate is arranged in advance over the entire length of the welding line inside the portion corresponding to the welding, and then the welded portion of the divided metal plate. And the inner surface of the thin metal plate are closely attached to the outer surface of the thin metal plate.In this state, the welded parts of the divided metal plate are welded, and the inside is vacuum-exhausted to form a vacuum layer. Can be configured.

At the time of performing the above-mentioned welding, the thin metal plate arranged on the back side (vacuum side) of the welded portion prevents the heat insulating material from being caught in the welded portion. The material is no longer melted and intervened, and defects such as pinholes and blowholes that may cause leakage do not occur, and welding defects do not occur. Also, since the outer surface of the thin metal plate is in close contact with the inner surface of the split metal plate, the amount of air in the gap is extremely small, and air is not replenished during welding, and the oxidation of the beads on the backside of the weld is extremely small. Therefore, a welded joint having sufficient strength can be formed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. As shown in FIG. 1, an outer wall 1 made of a metal plate has a main body (an example of a divided metal plate) 3 having an open portion 2.
And a lid (an example of a divided metal plate) 4 that is welded to the main body 3 after closing the opening 2. Then, into the main body 3, through the opening 2, the inner wall 5 made of a metal plate
And the inorganic fiber 6 which is an example of a heat insulating material.
Are filled as spacers. Here, as the inorganic fibers 6, fibers having a fiber diameter of less than 8 μ, such as glass wool and rock wool, having a small wire diameter are used.

After this inorganic fiber 6 is filled, an angled thin metal plate 7 is placed inside the edge of the main body 3 at the position of the open portion 2, and the outer surface 7a of one side thereof is brought into close contact with the inner surface 3a of the main body. , And pre-arranged along the entire length of the welding line. Here, as the thin metal plate 7, the same material as the main body 3 and the lid 4 is used.

Next, as shown in FIGS. 2 to 4, the lid 4 is brought into contact with the edge of the main body 3 to close the opening 2. This closing is performed by bringing the lid inner surface 4a into close contact with the outer surface 7b of the other side of the thin metal plate 7. In this closed state, the lid body 4 is welded 8 to the main body 3 and the inside is made into a vacuum layer by evacuation to form the vacuum heat insulator 9.

When the above-mentioned welding 8 is carried out, the thin metal plate 7 arranged on the back side (vacuum side) of the welded portion prevents the inorganic fibers 6 from being caught, and therefore the molten metal of the welded portion is prevented. The inorganic fibers 6 are not melted or intervened therein, pinholes, blowholes, etc. do not occur, and welding defects do not occur. The outer surfaces 7a and 7b on both sides of the thin metal plate 7 are the inner surface 3a of the main body.
Since it is in close contact with the lid inner surface 4a, the amount of air in the gap is extremely small, and since the air is not replenished during welding, oxidation of the beads on the back side of the welded portion is extremely reduced, and in terms of strength. Sufficient weld joints are formed.

It is desirable that the thin metal plate 7 has the following dimensions. Plate thickness ratio = (plate thickness of thin metal plate / plate thickness of body and lid plate) <1
/ 2 Width ratio = (width of thin metal plate / plate thickness of main body and lid plate)> 10 With the above plate thickness ratio, heat input during welding can be small and distortion can be prevented. Further, the ratio of the widths makes it possible to prevent air from entering the welded portions, prevent gas generated from the binder contained in the inorganic fibers 6 from entering the welded portions, and prevent inclusion of the inorganic fibers 6 in the welded portions. Well done.

FIG. 5 shows a second embodiment of the present invention. That is, the inorganic fibers 6 are filled, and the angle-shaped thin metal plate 7 is arranged such that the outer surface 7a of one side thereof is brought into close contact with the inner surface 3a of the main body, and then the lid 4 is fitted into the edge portion of the main body 3 and opened. The outer surface 7 of the other side of the thin metal plate 7 is closed by closing the portion 2.
b in close contact with the inner surface 4a of the lid, the lid 4 is attached to the main body 3
Welded to 8

Explaining an example of the material and dimensions here, SUS304 having a plate thickness T of 1.2 mm is used as the main body 3 and the cover plate 4, and the thin metal plate 7 has a plate thickness t of 0.5 mm and a width W of about 50 mm.
mm SUS304 is used, and rock wool is used as the inorganic fiber 6. As described above, the plate thickness t of the thin metal plate 7 is 1/2 or less of the plate thickness T of the main body 3 and the lid plate 4, and the width W of the thin metal plate 7 is the main body 3 and the lid. The thickness is set to be 10 times or more as large as the plate thickness T of the plate 4.

FIG. 6 shows a third embodiment of the present invention. That is, when the inorganic fibers 6 are filled, heat-resistant fibers 10 such as alumina-silica fibers are put in positions where the back surface of the thin metal plate 7 contacts. According to this, the thin metal plate 7
The heat-resistant fiber 10 located on the back side of is difficult to melt due to welding heat.

FIG. 7 shows a fourth embodiment of the present invention. That is, this is an example in the flat portion, and after filling the inorganic fibers 6 and arranging the strip-shaped thin metal plate 11 on the inorganic fibers 6 corresponding to the welded portion, the outer surface of the thin metal plate 11
A pair of flat metal plates (an example of divided metal plates) 12 on 11a,
Welding 8 is performed between the abutting portions in a state where the end faces are arranged so as to be in contact with each other. Here, the plate thickness T of the flat metal plate 12, the plate thickness t and the width W of the thin metal plate 11 are the same as those in the previous embodiment (FIG. 5).

In this case, the thin metal plate 11 prevents the inorganic fibers 6 from being caught, so that the inorganic fibers 6 are not dissolved and intervened in the molten metal at the welded portion, and the thin metal plate is also prevented. Since the outer surface 11a of 11 is in close contact with the inner surface 12a of the flat metal plate 12, the amount of air in the gap is extremely small, and since the air is not replenished during welding, oxidation of the bead on the back side of the welded part is prevented. Extremely low.

FIG. 8 shows a fifth embodiment of the present invention. That is, in the embodiment of the spherical portion, the inorganic fiber 6 is filled, and the curved thin metal plate 13 is arranged on the inorganic fiber 6 corresponding to the welded portion, and then the outer surface of the thin metal plate 13 is formed.
A pair of curved metal plates (an example of divided metal plates) 14 are provided on 13a.
Welding 8 is performed between the abutting portions in a state where the end faces are arranged so as to be in contact with each other.

Also in this case, the thin metal plate 13 prevents the inorganic fibers 6 from being caught up, so that the inorganic fibers 6 are not dissolved and intervened in the molten metal at the welded portion, and the thin metal plate 13 is also prevented. The outer surface 13a of the plate 13 is a curved metal plate
Since it is in close contact with the inner surface 14a of 14, the amount of air in the gap is extremely small, and since the air is not supplied during welding, the oxidation of the beads on the back side of the welded portion is extremely small.

An example of the material and dimensions will be explained here. SS41 having a plate thickness T of 2.5 mm is used as the curved metal plate 14, and the thin metal plate 13 having a plate thickness t of 1 mm and a width W of about 100 mm. S
S41 is used and glass wool is used as the inorganic fiber 6. The thin metal plate 13 has a welded portion facing the center thereof.

In each of the above-mentioned embodiments, it is necessary to adjust the welding current and the welding voltage so that the thin metal plate on the back side of the welded portion does not melt when the outer metal plate is welded.
In each of the above-mentioned examples, the fiber vacuum heat insulator using the inorganic fiber 6 as the heat insulating material is shown, but this may be a powder vacuum heat insulator using powder. Further, the fiber vacuum heat insulator and the powder vacuum heat insulator can be adopted for both low temperature and high temperature. Further, as can be seen from each of the examples, the shape of the vacuum heat insulator to which the present invention is applied is a pipe shape, a rectangular box shape,
There are various types such as a tank shape.

[0024]

According to the present invention having the above-described structure, when the welding between the welded portions of the divided metal plate is carried out, the thin metal plate disposed on the back side of the welded portion can prevent the heat insulating material from being caught, and thus the welding can be performed. It is possible to prevent the occurrence of welding defects that may cause leakage such as pinholes and blowholes because the heat insulating material is no longer dissolved and interposed in the molten metal of the part. In addition, the outer surface of the thin metal plate is in close contact with the inner surface of the divided metal plate, and the amount of air in the gap can be extremely reduced.
By preventing air supply during welding, oxidation of the bead on the back side of the welded portion can be extremely reduced, and a welded joint having sufficient strength can be formed.

As described above, according to the present invention, it is possible to prevent welding defects and prevent oxidation without increasing the size of the entire structure, and to obtain a vacuum heat insulating body in which the degree of vacuum does not decrease over a long period of time.

[Brief description of drawings]

FIG. 1 is a front view of a vacuum heat insulating body before welding, showing a first embodiment of the present invention.

FIG. 2 is a front view of the vacuum heat insulator after welding.

FIG. 3 is an enlarged view of a welded portion of the vacuum heat insulator.

FIG. 4 is a schematic perspective view showing a state in which a thin metal plate of the vacuum heat insulator is arranged.

FIG. 5 is an enlarged view of the welded portion of the vacuum heat insulating body according to the second embodiment of the present invention.

FIG. 6 shows a third embodiment of the present invention and is an enlarged view of a welded portion of a vacuum heat insulator.

FIG. 7 shows a fourth embodiment of the present invention and is an enlarged view of a welded portion of a vacuum heat insulator.

FIG. 8 shows a fifth embodiment of the present invention and is an enlarged view of a welded portion of a vacuum heat insulator.

FIG. 9 is a front view showing a conventional example before welding a vacuum heat insulator.

FIG. 10 is a front view of the vacuum heat insulator after welding.

FIG. 11 is an enlarged view showing a welding defect that may cause a leak in a welded portion of the vacuum heat insulating body.

FIG. 12 is an enlarged view showing an oxidized state of a back bead of a welded portion of the vacuum heat insulator.

FIG. 13 is another enlarged view of the welded portion of the vacuum heat insulator, showing another conventional example.

[Explanation of symbols]

 1 outer wall 2 open part 3 main body (divided metal plate) 4 lid (divided metal plate) 5 inner wall 6 inorganic fiber (heat insulating material) 7 thin metal plate 8 welding 9 vacuum heat insulator 10 heat resistant fiber 11 thin metal plate 12 flat metal Plate (divided metal plate) 13 Thin metal plate 14 Curved metal plate (divided metal plate)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shigeru Tanaka 2-26 Ohama-cho, Amagasaki City, Hyogo Prefecture Kubota Mukogawa Factory

Claims (1)

[Claims] 1. A vacuum heat insulator in which a heat insulating material is filled between an inner wall and an outer wall made of a metal plate and is kept in a vacuum, the outer wall is formed by a plurality of divided metal plates, and the heat insulating material is filled. Before welding between the divided metal plates with, vacuum insulation characterized by arranging a thin metal plate that adheres to both divided metal plates on the back side of the weld between the divided metal plates and over the entire length of the welding line Body weld structure.