KR101088464B1 - Heat insulation structure and cryogenic liquid storage tank having the same - Google Patents

Abstract

PURPOSE: A heat insulation structure and a cryogenic liquid storage tank with the same are provided to guarantee high robustness at an extremely low temperature and high sealing performance by welding instead of an adhesive. CONSTITUTION: A heat insulation structure(120) includes a heat insulation layer(121), a metal strip(133), a sub protecting wall(122), a main protecting wall(123), and an intermediate layer(124). The heat insulation layer is laminated on the inner wall of a tank. The metal strip is combined with the top of the heat insulation layer. The sub protecting wall is welded with the metal strip and laminated on the heat insulation layer. The main protecting wall is arranged on the sub protecting wall. The main and sub protecting walls have curved parts respectively. The intermediate layer is arranged between the main and sub protecting walls. A receiving groove(137) of the intermediate layer includes a curved part of the sub protecting wall.

Description

Heat-insulating structure and cryogenic liquid storage tank having the same {HEAT INSULATION STRUCTURE AND CRYOGENIC LIQUID STORAGE TANK HAVING THE SAME}

The present invention relates to a cryogenic liquid storage tank, and to a cryogenic liquid storage tank having an improved heat insulating structure and the same structure so that construction can be easily and have a high sealing performance.

Cryogenic liquids, such as LNG, liquid argon (LAR), liquid nitrogen (LIN), liquid oxygen (LOX), and liquid hydrogen (LH ₂ ), are insulated storage tanks to minimize liquid loss due to evaporation. Stored or transported in storage.

As an example of such a cryogenic liquid storage tank, the storage tank for liquefied natural gas is for storing the cryogenic liquefied natural gas of about -165 ℃, there are spherical type (Spherical Type) and membrane type (Membrane Type). Membrane type liquefied natural gas storage tank is the most widely used because of its larger loading capacity and simpler manufacturing than the spherical type liquefied natural gas storage tank. As the membrane type liquefied natural gas storage tank, MARK-III type and NO-96 type are known. The storage tank for liquefied natural gas has a structure in which an insulating structure for preventing leakage of liquefied natural gas and insulating the storage space in which the liquefied natural gas is stored is coupled to the inner wall of the tank.

The NO-96 type LNG storage tank uses Invar steel (36% nickel steel) with very low thermal expansion as the primary and secondary barriers, and an insulated box filled with pearlite is arranged between the barriers. . In contrast, the MARK-III type liquefied natural gas storage tank uses a stainless steel sheet with lattice-shaped bends as a primary barrier to absorb expansion and contraction due to thermal deformation, and a glass fiber composite material is formed on both sides of the aluminum foil. The bonded form of Triplex is used as the secondary barrier. Between the barriers a polyurethane foam is arranged for insulation.

These two types of LNG storage tanks are known to have similar gas evaporation rate (BOR, Boil-off rate), but compared to Invar membrane, stainless steel and triplex are cheaper, easier to install, and insulated from polyurethane foam. Due to its excellent effect, liquefied natural gas storage tanks of the MARK-III type are preferred.

However, since the bonding structure of the conventional secondary barrier using the adhesive is inferior in reliability, there is a problem in that the sealing performance and the integrity at cryogenic temperature are lowered. In order to increase the reliability of the secondary barrier joint structure, it is necessary to closely manage the adhesive thickness, the surface treatment of the adhesive surface, and the uniform curing conditions during the construction of the secondary barrier. However, there is a limit in managing the large joint structure. And there is a risk that the adhesive at the junction is broken by brittleness at cryogenic temperatures.

On the other hand, when transporting cryogenic liquids, such as LNG carriers, there is a problem that the barrier structure of the thermal insulation structure is damaged by the sloshing impact caused by the flow of cryogenic liquid generated inside the storage tank.

The present invention is to solve the problems of the conventional cryogenic liquid storage tank, and to provide an insulating structure and a cryogenic liquid storage tank having the same, which is easy to quality control and construction, excellent sealing performance and soundness at cryogenic temperature. do.

Insulating structure of the cryogenic liquid storage tank according to an embodiment of the present invention for achieving the above object, the insulating layer laminated on the inner wall of the tank having a storage space for cryogenic liquid is stored, a metal strip coupled to the upper surface of the insulating layer, A secondary barrier welded to a metal strip and stacked on the insulating layer and having a bent portion; a kitchen wall disposed on the secondary barrier to seal the cryogenic liquid stored in the storage space; and a kitchen wall disposed between the secondary barrier and the kitchen wall. And an intermediate layer having a receiving groove for accommodating the bent portion of the secondary barrier.

Insulating structure of the cryogenic liquid storage tank according to an embodiment of the present invention further comprises a metal strip coupled to the upper surface of the intermediate layer, the kitchen wall may be welded to the metal strip bonded to the intermediate layer.

Insulating structure of the cryogenic liquid storage tank according to an embodiment of the present invention further comprises a metal support coupled to the secondary barrier portion is exposed to the upper surface of the intermediate layer, the kitchen wall of the intermediate layer of the metal support It may be welded to the portion exposed to the upper surface.

The metal support may include a fixing part fixed to the sub-barrier, a support part welded to the kitchen wall, and a connection part connecting the fixing part and the support part to cushion the shock transmitted from the kitchen wall toward the sub-wall. So that it can be elastically deformed.

The welding coupling portion of the kitchen wall and the welding coupling portion of the sub-barrier may be alternately disposed.

The intermediate layer may include a heat insulating material made of a polymer foam.

The intermediate layer may have a sandwich structure in which a protective plate having a larger rigidity than the heat insulating material is coupled to both surfaces of the heat insulating material made of a polymer foam.

The intermediate layer is provided with an installation hole extending from the upper surface to the inside, a fixed end provided at the lower end of the installation hole, and an insertion hole extending from the fixed end to the lower surface of the intermediate layer. A support member having an end through which the insertion hole passes through the insertion hole is provided to protrude, and the intermediate layer may be fixed on the side wall by being coupled to the support member through the installation hole.

An elastic member may be interposed between the fixed end and the fixed member.

Adhesive may be filled in the installation hole.

Insulating structure of the cryogenic liquid storage tank according to an embodiment of the present invention may further include a buffer layer disposed between the secondary sub-barrier and the intermediate layer to buffer the shock transmitted from the kitchen wall toward the secondary barrier. .

The buffer layer may include a material selected from rubber, polymer foam, and glass fiber mat.

The intermediate layer may include a low rigid body capable of absorbing shock so as to buffer the shock transmitted from the kitchen wall toward the sub barrier.

The low rigid body may include a material selected from a spring washer, Belleville spring, rubber, polymer foam, glass fiber mat.

An interval between the kitchen wall and the secondary barrier may be equal to or less than a height of the curved portion of the secondary barrier, and the curved portion of the secondary barrier may be disposed below the curved portion of the kitchen wall.

Cryogenic liquid storage tank according to an embodiment of the present invention for achieving the above object, the tank inner wall having a storage space in which the cryogenic liquid is stored, a heat insulating layer laminated on the inner wall of the tank, a metal strip coupled to the upper surface of the heat insulating layer, A secondary barrier laminated on the insulating layer and welded to the metal strip and having a bent portion, a kitchen wall disposed on the secondary barrier and sealing the cryogenic liquid stored in the storage space, between the secondary wall and the kitchen wall. And an intermediate layer disposed and having a receiving groove for receiving the bent portion of the secondary barrier.

The cryogenic liquid storage tank according to the present invention has a structure in which not only the kitchen wall directly contacting the cryogenic liquid, but also the secondary barrier for sealing the cryogenic liquid when the kitchen wall is broken, has a bent portion and is joined by welding. Therefore, the heat stress generation by heat shrink is suppressed, and the sealing performance and the soundness at cryogenic temperature are excellent compared with the conventional bonding with an adhesive agent.

1 shows a cryogenic liquid storage tank according to an embodiment of the present invention.
Figure 2 shows a part of the cryogenic liquid storage tank according to an embodiment of the present invention.
Figure 3 shows a cryogenic liquid storage tank according to another embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, a thermal insulation structure and a cryogenic liquid storage tank having the same according to an embodiment of the present invention will be described in detail.

In describing the present invention, the sizes and shapes of the components shown in the drawings may be exaggerated or simplified for clarity and convenience of explanation. In addition, terms that are specifically defined in consideration of the configuration and operation of the present invention may vary depending on the intention or custom of the user or operator. These terms are to be construed in accordance with the meaning and concept consistent with the technical idea of the present invention based on the contents throughout the present specification.

1 and the cryogenic liquid storage tank 100 according to an embodiment of the present invention is between the tank inner wall 110 and the tank inner wall 110 and the storage space is provided with a storage space for storing the cryogenic liquid therein Insulation structure 120 is coupled to the tank inner wall 110 to prevent the movement of heat. The thermal insulation structure 120 is disposed on the secondary barrier 122 to seal the cryogenic liquid stored in the storage layer, the insulation layer 121 stacked on the tank inner wall 110, the insulation barrier 122 stacked on the insulation layer 121, and the storage space. The kitchen wall 123 and the intermediate layer 124 disposed between the kitchen wall 123 and the side wall 122 are included.

The heat insulation layer 121 is formed of a plurality of heat insulation panels 125 adjacent to each other on the tank inner wall 110. The insulation panel 125 has a sandwich structure including a heat insulating material 126 and a protective plate 127 coupled to both surfaces of the heat insulating material 126. As the heat insulator 126, a polymer foam having a low thermal conductivity may be used, and the protective plate 127 is made of a material having greater rigidity than the heat insulator 126. The protective plate 127 serves to increase the rigidity of the heat insulation layer 121 and prevent leakage of gas having low thermal conductivity filled in the pores of the polymer foam. The insulation panel 125 is fixed to the tank inner wall 110 by an adhesive method using an adhesive or a mechanical coupling method using a stud bolt or the like.

The secondary barrier 122 serves to prevent the cryogenic liquid from penetrating into the tank inner wall 110 when the kitchen wall 123 is destroyed, and the plurality of barrier sheets 128 are disposed on the upper surface of the heat insulating layer 121. It is made of a welded joint to the metal strip 130 is disposed. The barrier sheet 128 constituting the sub-barrier 122 may be made of various metal materials which do not cause a decrease in physical properties due to brittleness at cryogenic temperatures such as stainless steel or aluminum. The secondary barrier 122 has a plurality of bent portions 129 for suppressing the generation of thermal stress due to heat shrinkage. The metal strip 130 is made of a metal material having a predetermined thickness or more, which can be welded, and is fixed to an upper surface of the heat insulation layer 121 by an adhesive method or a mechanical fastening method.

The kitchen wall 123 is formed by welding a plurality of barrier sheets 131 to a metal strip 133 that is coupled to an upper surface of the intermediate layer 124. The barrier sheet 131 constituting the kitchen wall 123 may be made of various metal materials that do not cause a decrease in physical properties due to brittleness at cryogenic temperatures such as stainless steel or aluminum. The kitchen wall 123 has a plurality of bends 132 for suppressing generation of thermal stress due to heat shrinkage.

As shown in FIG. 1, the welding coupling portion of the kitchen wall 123 and the welding coupling portion of the subwall 122 are alternately disposed. When the welding coupling portion of the kitchen wall 123 and the welding coupling portion of the side wall 122 are alternately disposed, the breakage of the welding coupling portion of the kitchen wall 123 may be prevented from propagating due to the breakage of the welding coupling portion of the side wall 122. .

When the kitchen wall 123 and the side wall 122 are constructed close to each other, interference between the kitchen wall 123 and the side wall 122 may occur due to the sloshing impact force of the cryogenic liquid, and thus, the kitchen wall 123 and The secondary barrier 122 may be broken together. In addition, when the kitchen wall 123 is damaged due to various factors such as heat shrinkage, sloshing, deformation, and the like, there is a possibility that the damage is propagated to the secondary barrier 122. For this reason, the thickness of the intermediate layer 124 disposed between the kitchen wall 123 and the secondary barrier 122 is preferably greater than the height of the bent portion 129 of the secondary barrier 122. The intermediate layer 124 serves as a spacer for securing a space of a predetermined size or more between the kitchen wall 123 and the secondary barrier 122, and at the same time, serves as a secondary insulating layer that prevents heat transfer.

The intermediate layer 124 is composed of a plurality of insulating panels 134 are adjacent to each other on the side wall 122. The insulation panel 134 has a sandwich structure including a heat insulating material 135 and a protective plate 136 coupled to both sides of the heat insulating material 135. As the heat insulator 135, a polymer foam having a low thermal conductivity may be used, and the protective plate 136 is made of a material having greater rigidity than the heat insulator 135. The protective plate 136 serves to increase the rigidity of the intermediate layer 124 and to prevent leakage of gas having low thermal conductivity filled in the pores of the polymer foam. The intermediate layer 124 has a plurality of receiving grooves 137 for accommodating the bent portion 129 of the subwall 122. The insulation panel 134 constituting the intermediate layer 124 is fixed on the secondary barrier 122 by a mechanical coupling method.

1 and 2, the insulating panel 134 is provided with an installation hole 138, a fixed end 139, and an insertion hole 140 for mechanical coupling of the insulating panel 134, and the insulating layer ( The support member 141 protrudes from the metal strip 130 coupled to 121. The installation hole 138 extends inward from the upper surface of the heat insulation panel 134, and the fixing end 139 is provided at the lower end of the installation hole 138. The insertion hole 140 extends from the fixed end 139 to the lower surface of the heat insulation panel 134. The width of the installation hole 138 is larger than the width of the insertion hole 140. The width of the insertion hole 140 has a size through which the support member 141 can pass, and the width of the installation hole 138 is a fixing member 143 or an elastic member 144 coupled to the support member 141. It is made larger in size than its width.

The support member 141 is integrally provided with the metal strip 130 coupled to the heat insulation layer 121, and has a length through which the upper end of the support member 141 can be placed in the installation hole 138. An external thread 142 may be provided on an outer surface of the support member 141.

Insulating panel 134 constituting the intermediate layer 124 is a support member 141 is inserted into the insertion hole 140 and the installation hole 138 provided therein, and then the fixing member 143 through the installation hole 138 It is fixed on the secondary barrier 122 by being coupled to the support member 141. The fixing member 143 may have a female thread corresponding to the male thread 142 of the supporting member 141 to be screwed to the supporting member 141. An elastic member 144 may be interposed between the fixed end 139 of the insulation panel 134 and the fixing member 143. As the elastic member 144, a structure having various types of elastic forces that can prevent the fixing member 143 from being released from the supporting member 141 by providing a reaction force to the fixing member 143, such as a spring washer, may be used. . The elastic member 144 also serves to absorb the shock transmitted from the kitchen wall 123 toward the side wall 122.

As described above, the plurality of insulating panels 134 constituting the intermediate layer 124 are combined by a mechanical method using the supporting member 141 and the fixing member 143, so that the insulating panel 134 is in the surface direction (thermal insulation) in a cryogenic environment. It can contract freely in the direction parallel to the lower surface of the panel 134, and generation of thermal stress is suppressed. And compared with the adhesive method which uses an adhesive agent, workability improves by eliminating processes, such as adhesive hardening. In addition, when the insulating panel 134 is coupled by a mechanical method, it is easy to adjust the step of the insulating panel 134.

As shown in FIG. 2, the adhesive 145 may be filled in the installation hole 138 in which the support member 141 and the fixing member 143 are coupled. The adhesive 145 prevents loosening of the fixing member 143 and distributes structural loads applied to the supporting member 141 and the fixing member 143.

The buffer layer 146 is disposed between the sub barrier 122 and the intermediate layer 124. The buffer layer 146 serves to buffer the shock transmitted from the kitchen wall 123 toward the side wall 122. The buffer layer 146 may include a material selected from rubber, polymer foam, and fiberglass mat. The buffer layer 146 serves to alleviate the impact force applied to the kitchen wall 123 due to sloshing and the like, and to increase insulation performance. Although not shown, a buffer layer 146 may be disposed between the kitchen wall 123 and the intermediate layer 124.

Thus, the cryogenic liquid storage tank 100 according to an embodiment of the present invention, as well as the kitchen wall 123 directly contacting the cryogenic liquid, as well as the secondary barrier 122 for sealing the cryogenic liquid when the kitchen wall 123 is broken. It is also joined by the welding method. Therefore, the sealing performance and the soundness at cryogenicity improve compared with the conventional bonding by adhesive agent.

3 shows a cryogenic liquid storage tank 200 according to another embodiment of the present invention.

The cryogenic liquid storage tank 200 illustrated in FIG. 3 is similar to the cryogenic liquid storage tank 100 illustrated in FIGS. 1 and 2, and the tank inner wall 110 provided with a storage space for storing cryogenic liquid therein. And a thermal insulation structure 210 coupled to the tank inner wall 110 to prevent heat transfer between the tank inner wall 110 and the storage space. The insulation structure 210 is disposed on the insulation barrier 121 to be stacked on the tank inner wall 110, the insulation barrier 122 stacked on the insulation layer 121, and the cryogenic liquid stored in the storage space. The kitchen wall 123 and the intermediate layer 211 is disposed between the kitchen wall 123 and the secondary wall 122. Here, since the heat insulating layer 121, the secondary barrier 122 and the kitchen wall 123 is the same as the cryogenic liquid storage tank 100 shown in Figs. 1 and 2 will not be described in detail.

The kitchen wall 123 is coupled to the secondary barrier 122 and welded to the metal support 212, a portion of which is exposed to the top surface of the intermediate layer 211. The metal support 212 includes a fixing part 213 fixed to the side wall 122, a support part 214 welded to the kitchen wall 123, and a connecting part 215 connecting the fixing part 213 and the support part 214. It is made of a structure capable of elastic deformation including a. The metal support 212 serves as a medium for welding and joining the kitchen wall 123 to the secondary wall 122, and at the same time, buffers the shock transmitted from the kitchen wall 123 toward the secondary wall 122. .

The welding joint of the kitchen wall 123 and the welding joint of the side wall 122 are alternately arranged. When the welding coupling portion of the kitchen wall 123 and the welding coupling portion of the side wall 122 are alternately disposed, the breakage of the welding coupling portion of the kitchen wall 123 may be prevented from propagating due to the breakage of the welding coupling portion of the side wall 122. .

In the cryogenic liquid storage tank 200 according to another embodiment of the present invention, the distance between the kitchen wall 123 and the secondary barrier 122 is smaller than the height of the bent portion 129 of the secondary barrier 122. ) Serves to absorb the shock transmitted from the kitchen wall 123 to the sub-wall 122. The intermediate layer 211 includes a low rigid body 216 capable of shock absorption, and has an accommodating groove 217 for accommodating the bent portion 129 of the side wall 122. The low rigidity 216 may include a material selected from spring washers, Belleville springs, rubber, polymer foam, and fiberglass mats. In order to prevent interference between the kitchen wall 123 and the side wall 122, the curved portion 129 of the side wall 122 is disposed below the curved portion 132 of the kitchen wall 123.

Cryogenic liquid storage tank 200 according to another embodiment of the present invention has a small gap between the kitchen wall 123 and the secondary barrier 122, the impact force due to the sloshing applied to the kitchen wall 123, the secondary barrier 122 ), But it is possible to reduce the risk of breakage of the secondary barrier 122 due to the impact by absorbing the shock transmitted to the secondary barrier 122 by the intermediate layer 211. When the gap between the kitchen wall 123 and the secondary barrier 122 is reduced, the volume of the storage space capable of accommodating the cryogenic liquid may be increased.

In the present invention, the bent portion 132 of the kitchen wall 123 or the bent portion 129 of the side wall 122 is not limited to a structure protruding upward as shown. That is, the curved portion 132 of the kitchen wall 123 or the curved portion 129 of the side wall 122 may have a structure protruding downward. In this case, accommodation grooves for accommodating the bent portions 129 and 132 may be provided in the heat insulation layer 121 and the intermediate layer 124 and 211.

The embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical idea of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can improve and change the technical idea of the present invention in various forms. Accordingly, such improvements and modifications will fall within the protection scope of the present invention as long as it will be apparent to those skilled in the art.

100, 200: cryogenic liquid storage tank 110: tank inner wall
120, 210: heat insulation structure 121: heat insulation layer
122: side wall 123: kitchen wall
124, 211: middle layer 125, 134: insulation panel
126, 135: insulation 127, 136: protective plate
128, 131: barrier sheet 129, 132: bent portion
130, 133: metal strip 137, 217: receiving groove
138: mounting groove 139: fixed end
140: insertion hole 141: support member
143: fixing member 144: elastic member
145: adhesive 146: buffer layer
212: metal support 216: low rigid body

Claims (16)

Insulation structure coupled to the tank inner wall to insulate the storage space where the cryogenic liquid is stored,
An insulating layer laminated on the inner wall of the tank;
A metal strip coupled to the top surface of the heat insulation layer;
A secondary barrier welded to the metal strip and laminated on the insulating layer and having a bent portion;
A kitchen wall disposed on the secondary wall and having a bent portion to seal the cryogenic liquid stored in the storage space; And
And an intermediate layer disposed between the secondary barrier and the kitchen wall, the intermediate layer having an accommodation groove for accommodating the bent portion of the secondary barrier. The method of claim 1,
Further comprising a metal strip coupled to the upper surface of the intermediate layer,
The kitchen wall is an insulating structure of the cryogenic liquid storage tank, characterized in that welded to the metal strip bonded to the intermediate layer. The method of claim 1,
It further comprises a metal support coupled to the secondary barrier portion of which is exposed to the upper surface of the intermediate layer,
The kitchen wall is a heat insulating structure of the cryogenic liquid storage tank, characterized in that welded to the portion exposed to the upper surface of the intermediate layer of the metal support. The method of claim 3, wherein
The metal support may include a fixing part fixed to the sub-barrier, a support part welded to the kitchen wall, and a connection part connecting the fixing part and the support part to cushion the shock transmitted from the kitchen wall toward the sub-wall. Insulation structure of cryogenic liquid storage tank, characterized in that the elastic deformation so that. The method according to claim 2 or 3,
Insulating structure of the cryogenic liquid storage tank, characterized in that the welding coupling portion of the kitchen wall and the welding coupling portion of the secondary barrier are arranged alternately. The method of claim 1,
The intermediate layer is a heat insulating structure of cryogenic liquid storage tank comprising a heat insulating material made of a polymer foam. The method of claim 1,
The intermediate layer is a heat insulating structure of cryogenic liquid storage tank, characterized in that made of a sandwich structure combined with a protective plate of greater rigidity than the heat insulating material on both sides of the heat insulating material made of a polymer foam. The method according to claim 6 or 7,
The intermediate layer is provided with an installation hole extending from the upper surface to the inside, a fixed end provided at the lower end of the installation hole, and an insertion hole extending from the fixed end to the lower surface of the intermediate layer,
The metal strip coupled to the heat insulation layer is provided with a support member protruding from the insertion hole and having an end thereof placed in the installation hole.
The intermediate layer is a heat insulating structure of the cryogenic liquid storage tank, characterized in that the fixing member is coupled to the support member through the mounting hole is fixed on the secondary barrier. The method of claim 8,
Insulating structure of the cryogenic liquid storage tank, characterized in that the elastic member is interposed between the fixed end and the fixing member. Claim 10 was abandoned upon payment of a setup registration fee. The method of claim 8,
The insulating structure of the cryogenic liquid storage tank, characterized in that the adhesive is filled in the installation hole. The method according to claim 6 or 7,
Insulating structure of the cryogenic liquid storage tank further comprises a buffer layer disposed between the secondary sub-barrier and the intermediate layer to cushion the shock transmitted from the kitchen wall toward the sub-barrier. Claim 12 was abandoned upon payment of a registration fee. The method of claim 11,
The buffer layer is a heat insulating structure of a cryogenic liquid storage tank, characterized in that containing a material selected from rubber, polymer foam, glass fiber mat. The method of claim 1,
The intermediate layer is a heat insulating structure of the cryogenic liquid storage tank, characterized in that it comprises a low rigid material capable of absorbing shock to cushion the shock transmitted from the kitchen wall toward the secondary barrier. Claim 14 was abandoned when the registration fee was paid. The method of claim 13,
The low rigid body is a heat-insulating structure of cryogenic liquid storage tank, characterized in that it comprises a material selected from a spring washer, Belleville (spring), rubber, polymer foam, glass fiber mat. The method of claim 13,
The interval between the kitchen wall and the secondary barrier is less than the height of the bent portion of the secondary barrier, the bent portion of the secondary barrier is insulated structure of the cryogenic liquid storage tank, characterized in that disposed in the lower portion of the bent portion of the kitchen wall. An inner wall of the tank having a storage space in which the cryogenic liquid is stored;
An insulating layer laminated on the inner wall of the tank;
A metal strip coupled to the top surface of the heat insulation layer;
A secondary barrier welded to the metal strip and laminated on the insulating layer and having a bent portion;
A kitchen wall disposed on the secondary wall and having a bent portion to seal the cryogenic liquid stored in the storage space; And
And an intermediate layer disposed between the secondary barrier and the kitchen wall and having an accommodation groove for accommodating the bent portion of the secondary barrier.

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