JP2019128015A - Thermal insulation construction of tank - Google Patents

Abstract

To provide a thermal insulation construction of a tank where a joint part between adjoining panel parts is hardly damaged.SOLUTION: In a thermal insulation construction of a tank for covering an outer wall surface of the tank having at least partially a spherical surface shape by a thermal insulation material, the thermal insulation material comprises a plurality of panel parts each of which covers a part of the outer wall surface, and joint parts constituted by joint materials each arranged at a clearance between the adjoining panel parts; the clearance is defined as a first clearance part opened to cause one end to be faced against the outer wall surface, and a second clearance part having a larger width than that of the first clearance part, having one end thereof connected to the other end of the first clearance part, and having a first stepped surface where the other end of the first clearance part is opened; and the joint material comprises a first joint material arranged in the first clearance part, and a second joint material arranged in the second clearance part, and having a foamed joint material foamed in the second clearance part and a joint molded product arranged between the foamed joint material and the first stepped surface and having a lower Young's modulus than that of the foamed joint material.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to the heat protection structure of a tank for storing cryogenic materials such as liquefied natural gas (LNG).

  In general, a spherical tank that stores a cryogenic substance such as LNG has an outer wall surface coated with a heat insulating material in order to prevent evaporation of the cryogenic substance due to a temperature difference from the outside. The outer wall surface of the tank can be covered with a heat insulating material by arranging a plurality of panel portions formed in a transportable size on the outer wall surface of the tank and fixing the panels with bolts or the like. However, when it is attempted to cover the spherical outer wall surface with a panel portion having a flat structure, a discontinuous portion is formed at the joint between adjacent panel portions, and the heat insulation performance is degraded by heat penetration through this discontinuous portion. . For example, when LNG is injected into the tank, the tank is cooled to a temperature of about -160 ° C, so that the tank is thermally shrunk, and the heat shield is also thermally shrunk as the tank is shrunk. The metal forming the tank, such as aluminum, and the heat insulating material generally have different thermal conductivities and shrinkage rates, so the amount of deformation at the time of heat shrinkage is different from each other. It is easy for the department to occur.

  For example, Patent Document 1 discloses a conventional heat insulation structure using a planar panel portion. A schematic cross-sectional view of such a conventional heat shield structure is shown in FIG. A plurality of panel portions 102 are arranged on the outer wall surface 101 of the tank 100. The panel unit 102 includes a panel 103 made of phenol resin foam provided on the outer wall surface 101 and a panel 104 made of polyurethane foam fixed to the upper surface of the panel 103. The joint portion 105 formed in the gap between the adjacent panel portions 102, 102 is a joint made of polyurethane foam provided between the adjacent panels 103, 103 and a polyurethane foam joint foamed between the adjacent panels 104, 104. And the material 107.

Japanese Patent Application No. 2010-249174

  According to the FEM analysis of the present inventors, it has been clarified that when the tank 1 is thermally contracted, thermal stress is generated at the joint bottom 108 of the joint material 107. When the joint material 107 is cracked by this thermal stress, cold air leaks from the panel portion 102 and a cold spot is generated on the outer surface 102 a of the panel portion 102.

  In view of the above-described circumstances, at least one embodiment of the present disclosure aims to provide a heat protection structure of a tank in which joint portions between adjacent panel portions are less likely to be damaged.

(1) The heat protection structure of a tank according to at least one embodiment of the present invention is
A heat protection structure of a tank for covering the outer wall surface of a tank having at least a partially spherical shape with a heat protection material,
The heat shield is
A plurality of panel portions respectively covering a part of the outer wall surface;
And a joint composed of a joint material disposed in a gap between the adjacent panel units,
In the thickness direction of the panel portion, the gap is
A first gap that opens so that one end faces the outer wall surface;
A second gap portion having a width larger than a width of the first gap portion, wherein one end of the second gap portion is connected to the other end of the first gap portion, and the other end of the first gap portion. And a second gap portion having a first stepped surface on which
The joint material is
A first joint material provided in the first gap portion;
A second joint material provided in the second gap portion, the foam joint material foamed in the second gap portion, and provided between the foam joint material and the first stepped surface; And a second joint material having a joint molding product having a lower Young's modulus than the foam joint material.

  According to the configuration of (1), when the joint molded product having a Young's modulus lower than that of the foam joint material is provided between the foam joint material and the first stepped surface in the second gap portion, the tank thermally contracts The thermal stress generated in the joint is relieved by deformation of the joint molding, so that the joint between adjacent panel portions can be made difficult to break.

(2) In some embodiments, in the configuration of (1) above,
A first gas barrier film is provided to block the flow of air so as to close the opening at the other end of the first gap between the first stepped surface and the joint molding.

  According to the configuration of the above (2), even if the cold air cooled on the outer wall surface leaks through the first gap, the flow of the cold air can be blocked by the first gas barrier film, so the cold air from the panel portion Leakage can be reduced.

(3) In some embodiments, in the configuration of (1) or (2) above,
It is a second gas barrier film that blocks the flow of air, and is provided with a second gas barrier film that partitions the joint molded product and the foam joint material in the second gap portion.

  According to the configuration of (3), even if cold air cooled on the outer wall leaks through the first gap, the second gas barrier film can block the flow of the cold air, so the cold air from the panel portion Leakage can be reduced.

(4) In some embodiments, in any one of the above configurations (1) to (3),
A first mesh member is provided to cover the surface of the foam joint material exposed from the other end of the second gap portion.

  According to the configuration of the above (4), even if a crack occurs in the foamed joint material, the first mesh member covering the surface of the foamed joint material can suppress the expansion of the crack of the foamed joint material, so from the panel portion Leakage of cold air can be reduced.

(5) In some embodiments, in any one of the above configurations (1) to (4),
The gap is a third gap having a width larger than the width of the second gap, and one end of the third gap is connected to the other end of the second gap, and the second gap The joint material further includes a third joint material foamed in the third clearance portion, and the joint material further includes a third clearance portion having a second stepped surface having the other end opened.

  According to the configuration of (5), since the cold air can be sealed by the third joint material even if the foam joint material is cracked, the leakage of the cold air from the panel portion can be reduced.

(6) In some embodiments, in the configuration of (5) above,
A second mesh member is provided to cover the surface of the third joint material exposed from the other end of the third gap portion.

  According to the configuration of (6) above, even if a crack occurs in the third joint material, the second mesh member covering the surface of the third joint material can suppress the expansion of the crack in the third joint material.

(7) In some embodiments, in any one of the above configurations (1) to (6),
The panel portion has a vacuum heat insulating material inside.

  According to the configuration of the above (7), since the heat insulation performance of the panel portion is improved, the heat insulation performance of the heat shield can be improved.

(8) In some embodiments, in any one of the configurations (1) to (7),
The joint molded product is provided with a plurality of slits extending in a direction intersecting the width direction of the second gap portion.

  According to the configuration of (8) above, the joint-molded product has elasticity in the width direction of the second gap portion and can be deformed so as to bend in a direction perpendicular to the width direction of the second gap portion. Since the thermal stress is relieved by being deformed by the thermal stress generated when the heat shrinks, the joint portion between adjacent panel portions can be made difficult to break.

(9) In some embodiments, in any one of the above configurations (1) to (7),
The joint molding is formed of soft urethane, phenolic resin foam, or polyimide.

  According to the configuration of (9) above, the joint-molded product can maintain elasticity even at a low temperature, so that the thermal stress is relieved by deformation due to the thermal stress generated when the tank is thermally contracted. It is possible to make the joint difficult to break.

  According to at least one embodiment of the present disclosure, the tank may be thermally treated by providing a joint molding having a lower Young's modulus than the foam joint material between the foam joint material and the first stepped surface in the second gap portion. Since the thermal stress generated upon contraction is alleviated by deformation of the joint molded product, it is possible to make the joint between the adjacent panel parts less likely to be broken.

It is sectional drawing of the heat-insulation structure of the tank which concerns on Embodiment 1 of this indication. It is a fragmentary sectional view of the thermal insulation structure of the tank concerning Embodiment 1 of this indication. It is sectional drawing which shows the structure of the clearance gap between the panel parts of the heat insulation structure of the tank which concerns on Embodiment 1 of this indication. It is sectional drawing which shows the structure of the joint part between panel parts in the heat insulation structure of the tank which concerns on Embodiment 1 of this indication. It is a front view of the joint molding which comprises the joint part between panel parts in the heat protection structure of the tank which concerns on Embodiment 1 of this indication. It is sectional drawing which shows the structure of the joint part between panel parts in the heat insulation structure of the tank which concerns on Embodiment 2 of this indication. It is sectional drawing which shows the structure of the joint part between panel parts in the heat insulation structure of the tank which concerns on Embodiment 3 of this indication. It is a fragmentary sectional view of the heat insulation structure of the tank concerning Embodiment 4 of this indication. It is a fragmentary sectional view of the heat insulation structure of the conventional tank.

  Hereinafter, some embodiments of the present invention will be described with reference to the drawings. However, the scope of the present invention is not limited to the following embodiments. The dimensions, materials, shapes, relative arrangements, and the like of components described in the following embodiments are not intended to limit the scope of the present invention, but merely illustrative examples.

(Embodiment 1)
As shown in FIG. 1, the heat protection structure of the tank according to the first embodiment is configured such that the spherical outer wall 1 a of the tank 1 storing cryogenic materials such as LNG is covered with the heat shield 2. ing. As shown in FIG. 2, the heat insulating material 2 is constituted by a plurality of panel portions 3 which respectively cover a part of the outer wall surface 1a, and a joint material 6 disposed in the gap 4 between the adjacent panel portions 3 and 3. And the joint 5 to be Each panel portion 3 is formed of any known material having heat resistance performance, such as polyurethane foam, polystyrene foam, phenol resin foam and the like.

  As shown in FIG. 3, the gap 4 between the adjacent panel parts 3, 3 includes a first gap 41, a second gap 42 having a width larger than the width of the first gap 41, and a second A third gap portion 43 having a width larger than the width of the gap portion 42. In the following description, both ends of each of the first gap portion 41, the second gap portion 42, and the third gap portion 43 refer to an end portion in the thickness direction of the panel portion 3. One end 41 a of the first gap portion 41 is opened at the inner surface 3 a of the panel portion 3 so as to face the outer wall surface 1 a. One end 42 a of the second gap 42 is connected to the other end 41 b of the first gap 41. The second gap portion 42 has a first stepped surface 42 c in which the other end 41 b of the first gap portion 41 is opened. One end 43 a of the third clearance 43 is connected to the other end 42 b of the second clearance 42. The third gap portion 43 has a second stepped surface 43 c in which the other end 42 b of the second gap portion 42 is opened. The other end 43 b of the third gap portion 43 is open on the outer surface 3 b of the panel portion 3.

  As shown in FIG. 4, the joint material 6 constituting the joint unit 5 is provided in the second clearance 42 and the glass wool 11 a which is the first joint material 11 provided in the first clearance 41. A second joint material 12 and a third joint material 13 provided in the third gap 43 are provided. The second joint material 12 is a foamed joint material 15 made of a foamed resin such as polyurethane foam, polystyrene foam, phenol resin foam or the like that is foamed in the second gap portion 42, the foamed joint material 15, and the first stepped surface 42c. And a plurality of (for example, three) joint moldings 14 provided between the two.

  The third joint material 13 is a foamed resin such as a polyurethane foam, a polystyrene foam, or a phenol resin foam foamed in the third gap portion 43. In the 3rd clearance part 43, you may provide the 3rd joint material 13 in the state which accommodated the urethane block 17 which has a trapezoid-shaped cross section. In this case, since the injection amount of the raw material of the third joint material 13 can be reduced by the volume of the urethane block 17, the workability of providing the third joint material 13 in the third gap portion 43 can be improved.

  As shown in FIG. 5, the joint molded article 14 is a block structure 14a formed of polyurethane foam, expanded polystyrene or polyisocyanate foam, and a plurality of slits 14b are formed in the block structure 14a. . Each of the plurality of slits 14b is formed so as to extend in a direction intersecting the width direction of the second gap portion 42 (see FIG. 4) in which the joint molding 14 is provided, preferably in a vertical direction. With this configuration, the joint molding 14 can expand and contract in a direction perpendicular to the direction in which the slits 14 b extend, that is, in the width direction of the second gap 42, and has elasticity in this direction. The joint molding 14 is also deformable so as to bend in the direction in which the slit 14 b extends. Therefore, the elastic modulus, ie, the Young's modulus, of the joint molded product 14 is lower than that of the foamed joint material 15 (see FIG. 4).

  As shown in FIG. 1, when LNG is injected into the tank 1, the tank 1 is cooled to about −160 ° C. or so. Then, the tank 1 is thermally shrunk. As shown in FIG. 2, when the tank 1 is thermally shrunk, the amount of deformation at the time of heat shrinking is different from each other due to the difference in thermal conductivity and shrinkage rate of the materials constituting the tank 1 and the panel part 3. 5, thermal stress is generated in the extending direction of the panel unit 3 and in the thickness direction of the panel unit 3. As described above, according to the FEM analysis of the present inventors, as shown in FIG. 4, the first step of the second gap portion 42 of the second joint material 12 provided in the second gap portion 42 is provided. Thermal stress particularly occurs in the area near the surface 42c.

  In the heat insulating structure of the tank according to the first embodiment, the joint molded product 14 is provided between the foam joint material 15 and the first stepped surface 42c in the portion where the thermal stress is particularly likely to occur, that is, in the second gap portion 42. It has been. The joint molded product 14 has a lower Young's modulus than the foamed joint material 15 as described above. Then, since the thermal stress generated when the tank 1 is thermally shrunk can be relieved by the deformation of the joint molding 14, the joint portion 5 can be made less likely to be broken.

  In the first embodiment, a third gap portion 43 that opens on the outer surface 3 b of the panel portion 3 is formed on the outer surface 3 b side of the panel portion 3 with respect to the second gap portion 42, and a third gap portion 43 is formed in the third gap portion 43. The joint material 13 is provided, but the second gap portion 42 may be opened on the outer surface 3 b of the panel portion 3 without the third gap portion 43 and the third joint material 13. However, since the foam joint material 15 of the second joint material 15 and the third joint material 13 have the two-stage foam structure as in the first embodiment, the third foam foam material 15 is not damaged. Since cold air can be sealed by the joint material 13, leakage of cold air from the panel portion 3 can be reliably reduced.

Second Embodiment
Next, the heat insulating structure of the tank according to the second embodiment will be described. The heat protection structure of the tank according to the second embodiment is obtained by providing a gas barrier film for blocking the flow of air in the joint portion 5 with respect to the first embodiment. In the second embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.

  As shown in FIG. 6, the first gas barrier film 21 is placed between the first stepped surface 42 c and the joint molding 14 so as to close the opening of the other end 41 b (see FIG. 3) of the first gap 41. Is provided. Further, the second gas barrier film 22 is provided so as to partition the joint molding 14 and the foam joint material 15 in the second gap portion 42. Each of the first gas barrier film 21 and the second gas barrier film 22 is formed of polypropylene, Teflon (registered trademark) or the like, and has a function of blocking the flow of air. The first gas barrier film 21 and the second gas barrier film 22 may not be provided, but only one of them may be provided. The other configuration is the same as that of the first embodiment.

  When the tank 1 (see FIG. 2) thermally contracts, cold air between the outer wall surface 1a (see FIG. 2) of the tank 1 and the panel portion 3 (see FIG. 2) leaks through the first gap portion 41. Even so, the flow of cold air can be blocked by the first gas barrier film 21, so that the leakage of cold air from the panel portion 3 can be reduced. In addition, even if the cold air leaks through the first gap portion 41 when the first gas barrier film 21 is not provided, or even when the first gas barrier film 21 is provided, the cold air is the first gas barrier Even if the film 21 leaks, the flow of cold air can be blocked by the second gas barrier film 22, so that the leakage of cold air from the panel unit 3 can be reduced.

(Embodiment 3)
Next, the heat insulating structure of the tank according to the third embodiment will be described. The heat protection structure of the tank according to the third embodiment is obtained by providing a mesh member in the joint portion 5 for each of the first and second embodiments. The third embodiment will be described below in the form in which the mesh member is provided for the configuration of the first embodiment, but providing the mesh member for the configuration of the second embodiment (that is, both the gas barrier film and the mesh member The third embodiment can also be achieved by providing. In the third embodiment, the same components as those of the first embodiment are denoted by the same reference numerals, and the detailed description thereof is omitted.

  As shown in FIG. 7, the first mesh member 31 is formed between the second stepped surface 43 c and the third joint material 13 so as to cover the surface of the foam joint material 15 exposed from the other end of the second gap portion 42. It is provided between. Further, the second mesh member 32 is provided to cover the surface of the third joint material 13 exposed from the other end 43 b (see FIG. 3) of the third gap portion 43. Further, a third mesh member 33 is provided between the joint molded product 14 and the foam joint material 15 in the second gap portion 42. A well-known glass mesh etc. can be used as each of the 1st mesh member 31, the 2nd mesh member 32, and the 3rd mesh member 33. As shown in FIG. In addition, all the 1st mesh member 31, the 2nd mesh member 32, and the 3rd mesh member 33 may not be provided, but at least any one may be provided. The other configuration is the same as that of the first embodiment.

  A crack may occur in either or both of the foamed joint material 15 and the third joint material 13 due to the thermal stress generated when the tank 1 (see FIG. 2) is thermally shrunk. When a crack occurs in the foamed joint material 15, both surface sides are covered by the first mesh member 31 covering the radial outer surface of the foamed joint material 15 and the third mesh member 33 covering the radial inner surface of the foamed joint material 15 Thus, the expansion of the cracks in the foamed joint material 15 can be suppressed. In addition, when a crack occurs in the third joint material 13, the second mesh member 32 that covers the radially outer surface of the third joint material 13 and the first mesh member that covers the radially inner surface of the third joint material 13. 31 can suppress the expansion of cracks in the third joint material 13 from both surface sides. Therefore, even when a crack occurs in either or both of the foamed joint material 15 and the third joint material 13, leakage of cold air from the panel portion 3 can be reduced. Incidentally, although the foamed joint material 15 and the third joint material 13 respectively suppress the expansion of the crack from both the radially inner side and the outer side of each of the mesh members, the mesh member is so covered as to cover only one surface from one side. May be used to suppress the spread of the crack.

(Embodiment 4)
Next, the heat insulating structure of the tank according to the fourth embodiment will be described. The heat insulation structure of the tank which concerns on Embodiment 4 provides a vacuum heat insulating material in the panel part 3 with respect to each of Embodiment 1-3. Although the fourth embodiment will be described below in the form in which a vacuum heat insulating material is provided for the configuration of the first embodiment, the fourth embodiment is provided by providing the vacuum heat insulating material for the configuration of either the second embodiment or the third embodiment It can also be done. In the fourth embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and the detailed description thereof is omitted.

  As shown in FIG. 8, a vacuum heat insulating material 50 is provided in the panel portion 3. As the vacuum heat insulating material 50, for example, a heat insulating material in which a core material having a porous structure such as glass wool is coated with a laminate film and then the inside is depressurized and sealed can be used. It is available as Vacua®. The vacuum heat insulating material 50 has excellent heat insulating performance because the contribution of the thermal conductivity of the gas is almost zero.

  In Embodiment 4, since the heat insulation performance of the panel part 3 improves by providing the vacuum heat insulating material 50 in the panel part 3, compared with each of Embodiment 1-3, the heat insulation performance of the heat insulation material 2 is improved. Can be improved.

  The position where the vacuum heat insulating material 50 is provided in the thickness direction of the panel portion 3 can be arbitrarily changed in accordance with the material forming the panel portion 3.

  In Embodiments 1 to 4, as shown in FIGS. 4 and 6 to 8, each second joint material 12 includes three joint moldings 14, but is not limited to three. Depending on the size of the tank 1, the thickness or material of the panel portion 3, one, two, or four or more joint moldings 14 may be provided.

  In each of Embodiments 1 to 4, as shown in FIGS. 4 and 6 to 8, the first joint material 11 is a glass wool 11 a as a molded product, and a part of the second joint material 12 is molded into a joint product. Since the amount of work for injecting and foaming the foamed resin into the gap 4 at the site where the panel portion 3 is fixed to the tank 1 is reduced, the workability of forming the joint portion 5 can be improved. . The first joint material 11 is not limited to the glass wool 11a, and any material may be used as long as it has a function of sealing cold air.

  In each of the first to fourth embodiments, as shown in FIG. 5, the joint molding 14 is a block structure 14 a in which a plurality of slits 14 b are formed, but is limited to such a block structure 14 a. is not. The joint molding 14 may be a block structure formed of soft urethane, phenol resin foam, or polyimide and having no slit. When the joint molding 14 is a block structure formed of such a material, the joint molding 14 can maintain elasticity even at a low temperature, that is, an elastic modulus, that is, a modulus of elasticity compared to the foam joint 15 (see FIG. 4). Young's modulus is low. As a result, since the thermal stress is relieved by being deformed by the thermal stress generated when the tank 1 is thermally contracted, the joint portion 5 can be made difficult to be damaged.

  In each of the first to fourth embodiments, as shown in FIGS. 2 and 8, the panel unit 3 has a single-layer structure, but the present invention is not limited to this mode. As shown in FIG. 9 shown as a conventional heat insulation structure of a tank, it may have a two-layer structure in which two panels are stacked, or three layers in which three or more panels are stacked. It may be of the above structure.

  In each of Embodiments 1 to 4, the tank 1 is a perfect sphere, but is not limited to a perfect sphere. A form provided with an outer wall surface having a spherical shape at least partially, such as an elliptical sphere or a form in which a cylindrical part exists between two hemispheres, may be used.

DESCRIPTION OF SYMBOLS 1 Tank 1a Outer wall surface 2 (of tank) Thermal insulation material 3 Panel part 3a Inner surface 3b (of panel part) Outer surface 4 Clearance 5 Joint part 6 Joint material 11 First joint material 11a Glass wool 12 Second joint Material 13 Third joint material 14 Joint molding 14a Block structure 14b Slit 15 Foam joint material 17 Urethane block 21 First gas barrier film 22 Second gas barrier film 31 First mesh member 32 Second mesh member 33 Third mesh member 41 First 1 gap 41a (first gap) one end 41b (first gap) other end 42 2nd gap 42a (second gap) one end 42b (second gap) other end 43 3rd gap Portion 43a One end 43b (of the third gap portion) The other end 50 (of the third gap portion) 50 Vacuum heat insulating material 100 Tank 101 (of the tank) Outer wall surface 102 Panel portion 102a Outer surface 103 (panel part) Panel 104 Panel 105 Joint part 106 Glass wool 107 Joint material

Claims (9)

A heat protection structure of a tank for covering the outer wall surface of a tank having at least a partially spherical shape with a heat protection material,
The heat shield is
A plurality of panel portions respectively covering a part of the outer wall surface;
A joint portion constituted by a joint material disposed in a gap between the adjacent panel portions, and
In the thickness direction of the panel portion, the gap is
A first gap that opens so that one end faces the outer wall surface;
A second gap portion having a width larger than a width of the first gap portion, wherein one end of the second gap portion is connected to the other end of the first gap portion, and the other end of the first gap portion. And a second gap portion having a first stepped surface on which
The joint material is
A first joint material provided in the first gap portion;
A second joint material provided in the second gap portion, the foam joint material foamed in the second gap portion, and provided between the foam joint material and the first stepped surface; A heat-insulated structure of a tank comprising: a second joint material having a joint molded product having a Young's modulus lower than that of a foam joint material.   The 1st gas barrier film which interrupts | blocks the flow of air is provided so that the opening of the said other end of the said 1st clearance gap may be plugged between the said 1st stepped surface and the said joint molding product. Thermal protection structure of the tank described in.   The second gas barrier film for blocking the flow of air, according to claim 1 or 2, further comprising a second gas barrier film for partitioning the joint molding and the foam joint material in the second gap portion. Heat insulation structure of the tank.   The heat insulation structure of the tank as described in any one of Claims 1-3 with which the 1st mesh member is provided so that the surface of the said foam joint material exposed from the other end of the said 2nd clearance gap part may be covered.   The gap is a third gap having a width larger than the width of the second gap, and one end of the third gap is connected to the other end of the second gap, and the second gap is The third gap portion having a second stepped surface that is open at the other end of the second gap, and the joint material further includes a third joint material foamed in the third gap portion. The heat protection structure of the tank according to any one of the preceding claims.   The heat protection structure for a tank according to claim 5, wherein a second mesh member is provided to cover the surface of the third joint material exposed from the other end of the third gap portion.   The heat protection structure of the tank according to any one of claims 1 to 6, wherein the panel portion has a vacuum heat insulating material inside.   The heat insulation structure for a tank according to any one of claims 1 to 7, wherein the joint-molded product is provided with a plurality of slits extending in a direction intersecting the width direction of the second gap portion. The heat protection structure of a tank according to any one of claims 1 to 7, wherein the joint molded product is formed of a soft urethane, a phenol resin foam, or a polyimide.

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