Multi-shell tank

Abstract

To provide an improved connection structure for a first tank and a second tank containing the first tank, in a multiple shell tank comprising the first tank and the second tank.SOLUTION: A multiple shell tank comprises: a first tank comprising a first tank bottom plate, and a cylindrical first tank side plate erected from the first tank bottom plate; a second tank comprising a second tank bottom plate arranged below the first tank bottom plate, and a cylindrical second tank side plate erected from the second tank bottom plate, and surrounding the first tank side plate at an interval; and a first anchor strap arranged between the first tank and the second tank, and connecting the first tank side plate and the second tank side plate.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a flat-bottomed multi-shell tank for storing low-temperature liquefied gas.

Background Art

[0002] Conventionally, flat-bottomed multi-shell tanks for storing low-temperature liquefied gas have been proposed. For example, in Patent Document 1, a flat-bottomed triple-shell tank is disclosed.

[0003] In the triple-shell tank disclosed in Patent Document 1, an outer tank is provided on a concrete tank foundation, a substrate made of perlite concrete having a heat-insulating effect is provided on the bottom plate of the outer tank, an intermediate tank is provided on this substrate, a level concrete layer is provided on the bottom plate of the intermediate tank, and an inner tank is provided on the level concrete layer. An attachment seat for slidably supporting the peripheral edge of the bottom plate of the inner tank is provided between the upper and lower portions of the bottom plate of the inner tank and the level concrete layer. The outer peripheral edge portion of the attachment seat extends to near the inner wall of the intermediate tank and can abut against a locking piece provided on the side plate of the intermediate tank from below. One end of the first anchor strap is connected to the side plate of the inner tank and the other end is connected to the attachment seat. One end of the second anchor strap is connected to the side plate of the intermediate tank and the other end extends into the tank foundation and is fixed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the triple-walled tank described in Patent Document 1, when the inner tank attempts to float and an upward force acts on the first anchor strap, this upward force is transmitted to the mounting base via the first anchor strap, then from the mounting base to the intermediate tank via the locking piece, and finally from the intermediate tank to the tank foundation via the second anchor strap. The upward force is supported by the weight of the inner tank containing the liquid pressing down on the mounting base and the pull-out resistance force of the second anchor strap. In Patent Document 1, since the mounting base to which the lower end of the first anchor strap is attached is laid beneath the inner tank, as the size of the tank increases, the mounting base also becomes larger, leading to increased costs and making construction more difficult.

[0006] This disclosure is made in view of the above circumstances and aims to propose an improved connection structure between the first and second tanks in a multi-shell tank comprising a first tank and a second tank containing the first tank. [Means for solving the problem]

[0007] To solve the above problems, a multi-shell tank according to one aspect of this disclosure is: A first tank having a first tank bottom plate and a cylindrical first tank side plate rising from the first tank bottom plate, and containing liquefied gas, A second tank having a second tank bottom plate positioned below the first tank bottom plate, and a cylindrical second tank side plate that rises from the second tank bottom plate and surrounds the first tank side plate at a distance from each other, The system includes a first anchor strap positioned between the first and second tanks, connecting the side plate of the first tank and the side plate of the second tank. [Effects of the Invention]

[0008] According to this disclosure, in a multi-shell tank comprising a first tank and a second tank containing the first tank, an improved connection structure between the first tank and the second tank can be provided. [Brief explanation of the drawing]

[0009] [Figure 1]Figure 1 is a longitudinal cross-sectional view showing the overall configuration of a multi-shell tank according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a partial longitudinal cross-sectional view of a multi-shell tank showing the connection structure between the inner tank side plate and the intermediate tank side plate. [Figure 3] Figure 3 is a cross-sectional view of the inner tank and intermediate tank showing the connection structure between the inner tank side plate and the intermediate tank side plate. [Figure 4] Figure 4 is a partial longitudinal cross-sectional view of an intermediate groove showing a stiffening member positioned between adjacent supports in the circumferential direction. [Figure 5] Figure 5 is a partial cross-sectional view of the intermediate groove showing the stiffening member. [Figure 6] Figure 6 is a cross-sectional view of the inner and intermediate tanks, which are equipped with braces connecting adjacent supports in the circumferential direction. [Figure 7] Figure 7 is a partial longitudinal cross-sectional view of a multi-shell tank showing the connection structure between the inner tank side plate and the intermediate tank side plate. [Modes for carrying out the invention]

[0010] Embodiments of the present invention will be described with reference to the drawings. Figure 1 is a cross-sectional view showing the overall configuration of a multi-shell tank 1 according to one embodiment of the present disclosure.

[0011] The multi-shell tank 1 shown in Figure 1 is a ground-mounted, flat-bottomed, triple-shell tank. The multi-shell tank 1 comprises a concrete tank foundation 7, an outer tank 5 placed on the tank foundation 7, an intermediate tank 4 enclosed within the outer tank 5, and an inner tank 3 enclosed within the intermediate tank 4. However, the structure of the multi-shell tank 1 according to this embodiment is not limited to a triple-shell tank and can be applied to a double or more multi-shell tank comprising an inner tank 3 for containing liquefied gas and at least one tank surrounding the inner tank 3. A concrete containment dike 6 is provided around the multi-shell tank 1.

[0012] The outer tank 5 has a flat outer tank bottom plate 51 provided on the tank foundation 7, cylindrical outer tank side plates 52 rising from the outer tank bottom plate 51, and a hemispherical shell-shaped outer tank roof 53 provided on the upper part of the outer tank side plates 52. The outer tank side plates 52 are connected to the tank foundation 7 by anchor bolts 56. Alternatively, the outer tank bottom plate 51 may be fixed to anchor plates driven into the tank foundation 7.

[0013] The intermediate tank 4 is surrounded by the outer tank 5. The intermediate tank 4 has a flat intermediate tank bottom plate 41, cylindrical intermediate tank side plates 42 that rise from the intermediate tank bottom plate 41, and a hemispherical shell-shaped intermediate tank roof 43 provided on the upper part of the intermediate tank side plates 42. The intermediate tank bottom plate 41 is placed on the outer tank bottom plate 51 via a level concrete layer 45 and a first bottom insulation layer 46.

[0014] The inner tank 3 is surrounded by the intermediate tank 4. The inner tank 3 has a flat inner tank bottom plate 31, cylindrical inner tank side plates 32 that rise from the inner tank bottom plate 31, and a hemispherical shell-shaped inner tank roof 33 provided on the upper part of the inner tank side plates 32. The inner tank bottom plate 31 is placed on the intermediate tank bottom plate 41 via a level concrete layer 35 and a second bottom insulation layer 36. The inner tank 3 is a container for holding cryogenic liquefied gas. Examples of cryogenic liquefied gases include liquid helium, liquid hydrogen, liquid nitrogen, LNG, and LPG. A BOG pipe 22 opens at the top of the inner tank 3. This BOG pipe 22 penetrates the tops of the inner tank 3, the intermediate tank 4, and the outer tank 5, and vaporized gas generated in the inner tank 3 is sent to the outside of the multi-shell tank 1 through the BOG pipe 22. Although BOG piping 22 was used as an example of piping connecting the inside and outside of the multi-shell tank 1, other piping such as receiving piping for receiving liquefied gas into the inner tank 3 and discharging piping for discharging liquefied gas from the inner tank 3 are also arranged in a similar manner.

[0015] The intermediate tank side plate 42 surrounds the inner tank side plate 32 with a radial spacing, and a first inter-tank space 61 is formed between the inner tank 3 and the intermediate tank 4. Further, the outer tank side plate 52 surrounds the intermediate tank side plate 42 with a radial spacing, and a second inter-tank space 62 is formed between the intermediate tank 4 and the outer tank 5. Heat insulating materials may be arranged in the first inter-tank space 61 and the second inter-tank space 62. The heat insulating materials may be those that have been conventionally used as heat insulating materials for double-wall tanks, such as perlite, glass wool, heat insulating panels, etc.

[0016] The first inter-tank space 61 is filled with a gas of the same type as the vaporized gas of the liquefied gas stored in the inner tank 3, or a gas with an equivalent low boiling point. A communication pipe for communicating the upper part inside the inner tank 3 and the first inter-tank space 61 is provided on the inner tank roof 33, and the vaporized gas of the liquefied gas may be introduced into the first inter-tank space 61 through the communication pipe. The second inter-tank space 62 is filled with an inert gas. This inert gas is a gas with a boiling point higher than that of the liquefied gas stored in the inner tank 3. Nitrogen is exemplified as such an inert gas.

[0017] The inner tank side plate 32 and the intermediate tank side plate 42 are connected via a first anchor strap 9. A number of first anchor straps 9 are arranged circumferentially at substantially equal intervals around the inner tank side plate 32 in the first inter-tank space 61. The intermediate tank side plate 42 and the tank foundation 7 are connected via a second anchor strap 10. A number of second anchor straps 10 are arranged circumferentially at substantially equal intervals around the intermediate tank side plate 42 in the second inter-tank space 62. The upper end of the second anchor strap 10 is joined to the intermediate tank side plate 42 by welding or other methods, and the lower end of the second anchor strap 10 penetrates the outer tank bottom plate 51 and is joined by welding to an anchor box 72 embedded in the tank foundation 7. The first anchor strap 9 and the second anchor strap 10 are strip-shaped, shaft-shaped, or linear members made of a material having low-temperature toughness (e.g., SUS).

[0018] 〔Connection structure between the inner tank side plate 32 and the intermediate tank side plate 42〕 Here, the connection structure between the inner tank side plate 32 and the intermediate tank side plate 42 by the first anchor strap 9 will be described in detail. FIG. 2 is a partial longitudinal sectional view of the multi-shell tank 1 showing the connection structure between the inner tank side plate 32 and the intermediate tank side plate 42.

[0019] As shown in FIG. 2, the upper end portion of the first anchor strap 9 is connected to the inner tank side plate 32 by a coupling tool 70 disposed on the outer wall of the inner tank side plate 32. The coupling tool 70 connects the first anchor strap 9 to the inner tank side plate 32 so as to prevent circumferential movement with respect to the inner tank side plate 32 and allow vertical movement with respect to the inner tank side plate 32. For example, the coupling tool 70 includes a pair of seat plates 73 fixed to the outer wall of the inner tank side plate 32 and a stopper plate 75 spanned over the pair of seat plates 73. A locking tool 76 is attached to the upper end portion of the first anchor strap 9. The upper end portion of the first anchor strap 9 is passed through a space surrounded by the inner tank side plate 32, the pair of seat plates 73, and the stopper plate 75, and the locking tool 76 of the first anchor strap 9 is locked to the stopper plate 75, thereby restricting the downward withdrawal of the first anchor strap 9.

[0020] The lower end portion of the first anchor strap 9 is connected to the intermediate tank side plate 42 via a support 8 fixed to the inner wall of the intermediate tank side plate 42. FIG. 3 is a cross-sectional view of the inner tank 3 and the intermediate tank 4 showing the connection structure between the inner tank side plate 32 and the intermediate tank side plate 42. As shown in FIG. 3, a plurality of supports 8 are arranged on the inner wall of the intermediate tank side plate 42 at substantially equal intervals. Each support 8 projects radially from the inner wall of the intermediate tank side plate 42 toward the inner tank side plate 32, and the lower end portion of the first anchor strap 9 is coupled to the protruding end thereof.

[0021] By coupling the first anchor strap 9 to the protruding end of the support 8, it is possible to bring the radial positions of the upper end portion and the lower end portion of the first anchor strap 9 closer to each other so that the first anchor strap 9 assumes a more vertical posture, that is, the angle formed by the inner tank side plate 32 and the first anchor strap 9 becomes smaller.

[0022] In the inner wall of the intermediate tank side plate 42, stiffening members 85 are arranged between circumferentially adjacent support members 8. The stiffening members 85 can suppress buckling and deformation of the intermediate tank side plate 42. Figure 4 is a partial longitudinal section view of the intermediate tank 4 showing the stiffening members 85 arranged between circumferentially adjacent support members 8, and Figure 5 is a partial transverse section view of the intermediate tank showing the stiffening members 85. As shown in Figures 4 and 5, the stiffening members 85 are block-shaped or plate-shaped members and are joined to the intermediate tank side plate 42 and the intermediate tank bottom plate 41, respectively. The form of the stiffening members 85 is not particularly limited, but the stiffening members 85 exemplified in Figures 4 and 5 have a base plate 85a and reinforcing ribs 85b. The base plate 85a is a plate-shaped member that rises from the intermediate tank bottom plate 41 and has a first side joined to the intermediate tank side plate 42 and a second side joined to the intermediate tank bottom plate 41. The reinforcing rib 85b has a surface perpendicular to the substrate 85a and has a first side joined to the substrate 85a and a second side joined to the intermediate tank side plate 42.

[0023] Figure 6 is a cross-sectional view of the inner tank 3 and intermediate tank 4, which are equipped with braces 86 connecting adjacent support members 8 in the circumferential direction. As shown in Figure 6, adjacent support members 8 in the circumferential direction may be connected by braces 86. For example, a pair of braces 86 are crossed and stretched between adjacent support members 8. Preferably, all support members 8 in the intermediate tank 4 are connected in a ring shape by braces 86. By stretching braces 86 between adjacent support members 8 in this way, the torsional rigidity of each support member 8 is increased.

[0024] The support 8 is joined to the intermediate tank side plate 42, and the support 8 behaves integrally with the intermediate tank side plate 42. The form of the support 8 is not particularly limited, but for example, a frame-shaped support 8A (see Figure 2) or a bracket-shaped support 8B (see Figure 7) may be used. The frame-shaped support 8A and the bracket-shaped support 8B will be described below, respectively.

[0025] (Frame-shaped support 8A) In the example shown in Figure 2, an L-shaped or V-shaped frame-like support 8A is used as the support 8. The frame-like support 8A is formed by joining, for example, a beam member 81 that protrudes radially from the inner wall of the intermediate tank side plate 42 and a reinforcing member 82 that extends between the protruding end 81b of the beam member 81 and the inner wall of the intermediate tank side plate 42, so that the whole structure forms an L-shape or a V-shape. The beam member 81 and the reinforcing member 82 are not particularly limited, but may be made of structural steel or built-up structural steel having low-temperature toughness, or plate-like members. Each of the beam member 81 and the reinforcing member 82 may have stiffening parts such as stiffeners or reinforcing ribs to further increase rigidity.

[0026] The base end 81a of the beam member 81 is joined to the inner wall of the intermediate tank side plate 42. The beam member 81 and the intermediate tank side plate 42 may be joined by fusion welding or mechanical welding. The beam member 81 and the intermediate tank side plate 42 may be joined directly or joined via a gusset plate. The beam member 81 extends approximately horizontally or diagonally upward toward the inner tank 3 from the base end 81a joined to the intermediate tank side plate 42. In a plan view, the protruding end 81b of the beam member 81 is located between the inner tank side plate 32 and the intermediate tank side plate 42, and does not reach the inner tank side plate 32. A connecting portion 80 is provided at the protruding end 81b of the beam member 81, to which the lower end of the first anchor strap 9 is joined. The connecting portion 80 is preferably located between the inner tank bottom plate 31 and the intermediate tank bottom plate 41 in the vertical direction, and it is even more preferable that the beam member 81 as a whole is positioned between the inner tank bottom plate 31 and the intermediate tank bottom plate 41 in the vertical direction.

[0027] The base end 82a of the reinforcing member 82 is joined to the inner wall of the intermediate tank side plate 42 at a location above where the base end 81a of the beam member 81 is joined. The reinforcing member 82 and the intermediate tank side plate 42 may be joined by fusion welding or mechanical welding. The reinforcing member 82 and the intermediate tank side plate 42 may be joined directly or through a gusset plate. The reinforcing member 82 extends diagonally downward from the base end 82a joined to the intermediate tank side plate 42 toward the protruding end 81b of the beam member 81. The tip 82b of the reinforcing member 82 is joined to the protruding end 81b of the beam member 81. Such a reinforcing member 82 is positioned to be able to brace between the inner wall of the intermediate tank side plate 42 and the protruding end 81b of the beam member 81. In the frame-shaped support 8A with the above configuration, when an upward force acts on the first anchor strap 9, tensile stress is generated in the beam member 81 and compressive stress is generated in the reinforcing member 82. In the above-described frame-shaped support 8A, the beam member 81 and the reinforcing member 82, the beam member 81 and the intermediate tank side plate 42, and the reinforcing member 82 and the intermediate tank side plate 42 are rigidly joined to each other. However, they may also be pin-jointed to each other so that a truss structure is realized by the beam member 81, the reinforcing member 82, and the intermediate tank side plate 42.

[0028] (Bracket-shaped support 8B) In the example shown in Figure 7, a bracket-shaped support 8B is used as the support 8. The bracket-shaped support 8B is, for example, a plate-shaped member that protrudes substantially horizontally in the radial direction from the inner wall of the intermediate tank side plate 42, and the bracket-shaped support 8B has a connecting portion 80 at its protruding end, to which the lower end of the first anchor strap 9 is connected.

[0029] The shape of the bracket-shaped support 8B is not particularly limited, but may be a triangular bracket, for example. The triangular bracket may be composed of a flanged plate, for example. The base of the triangular bracket, which extends vertically, is joined to the inner wall of the intermediate tank side plate 42, and the joint portion 80 is located at the apex of the triangular bracket. The bracket-shaped support 8B and the intermediate tank side plate 42 may be joined by fusion welding or mechanical welding. The bracket-shaped support 8B and the intermediate tank side plate 42 may be joined directly or joined via a gusset plate. The bracket-shaped support 8B is provided with reinforcing ribs or other stiffening parts as appropriate to prevent buckling and deformation.

[0030] (Reinforcement ring 87) When force is applied to the first anchor strap 9, a large localized stress is generated at the joint between the intermediate tank side plate 42 and the support 8. Therefore, to prevent deformation due to the localized stress acting on the intermediate tank side plate 42, a stiffening member (stiffening ring 87) is provided to reinforce the rigidity of the intermediate tank side plate 42. As shown in Figures 2 and 7, the stiffening ring 87 is located on the outer wall of the intermediate tank side plate 42 at or near the height where the support 8 is joined. The stiffening ring 87 is a ring-shaped member that is continuous in the circumferential direction on the outer wall of the intermediate tank side plate 42, and the inner circumference of the stiffening ring 87 is joined to the outer wall of the intermediate tank side plate 42. In order to avoid interference between the stiffening ring 87 and the second anchor strap 10, a notch may be provided in the stiffening ring 87 at the point where it intersects with the second anchor strap 10.

[0031] In the example shown in Figure 2, stiffening rings 87 are provided on the outer wall of the intermediate tank side plate 42 at vertical positions corresponding to the upper and lower ends of the base end 81a of the beam member 81 of the frame-shaped support 8A, and at vertical positions corresponding to the upper and lower ends of the base end 82a of the reinforcing member 82.

[0032] Furthermore, in the example shown in Figure 7, a stiffening ring 87 is provided on the outer wall of the intermediate tank side plate 42 at vertical positions corresponding to the upper and lower ends of the bracket-shaped support 8B.

[0033] The stiffening ring 87 may be made of structural steel or built-up structural steel. The stiffening ring 87 may have a reinforcing structure to further improve the rigidity of the intermediate tank side plate 42. For example, as shown in Figures 4 and 5, the stiffening ring 87 may have a flange 91 to improve its strength. Alternatively, for example, a plate-shaped stiffening member 92 may be provided to connect the stiffening rings 87 that are arranged in the vertical direction. Alternatively, for example, a plate-shaped stiffening member 93 may be provided joined to the stiffening ring 87 and the intermediate tank side plate 42, respectively.

[0034] Furthermore, the stiffening member 85 may be configured to prevent buckling of the stiffening ring 87. Specifically, the stiffening member 85 joined to the intermediate tank side plate 42 is positioned to overlap with the stiffening ring 87 in the vertical direction. Here, if the reinforcing rib 85b of the stiffening member 85 is positioned to overlap with the stiffening ring 87 in the vertical direction, the stiffening member 85 can more effectively prevent buckling of the stiffening ring 87.

[0035] [Behavior of multi-shell tank 1 under the action of buoyancy force] In the multi-shell tank 1 with the above configuration, an upward force acts on the inner tank 3 due to an increase in the gas pressure in the inner tank 3 or vibrations caused by earthquakes, etc. However, if the inside of the inner tank 3 is connected to the first tank 61, the upward movement of the inner tank 3 due to an increase in the gas pressure in the inner tank 3 does not need to be considered much. The behavior of the multi-shell tank 1 when an upward force is applied will be described below.

[0036] When an upward force acts on the inner tank 3, an upward force is generated in the first anchor strap 9, which is connected to the inner tank side plate 32. This upward force in the first anchor strap 9 is transmitted to the intermediate tank side plate 42, which is connected to the first anchor strap 9. Here, the support 8, to which the first anchor strap 9 is directly connected, is joined to the intermediate tank side plate 42, and the intermediate tank side plate 42 and the support 8 are a single unit, so the upward force in the first anchor strap 9 is transmitted substantially directly to the intermediate tank side plate 42. The upward force transmitted to the intermediate tank side plate 42 is then transmitted to the second anchor strap 10, which is connected to the intermediate tank side plate 42. The upward force transmitted to the second anchor strap 10 is then offset by the reaction force due to the pull-out resistance of the second anchor strap 10 from the tank foundation 7 (specifically, the anchor box 72). In this way, the inner tank 3 is prevented from floating up. Furthermore, since multiple first anchor straps 9 are arranged at approximately equal intervals around the outer circumference of the inner tank 3, and multiple second anchor straps 10 are arranged at approximately equal intervals around the outer circumference of the intermediate tank 4, even when a lateral force acts on the inner tank 3, lateral slippage of the inner tank 3 is prevented, similar to the behavior when a buoyant force is applied.

[0037] As described above, in the multi-shell tank 1, the intermediate tank side plate 42 (and support 8) functions as a force transmission member between the first anchor strap 9 and the second anchor strap 10. The inner tank side plate 32 and the intermediate tank side plate 42 are spaced radially apart, and the intermediate tank side plate 42 and the outer tank side plate 52 are also spaced radially apart, so the intermediate tank side plate 42 has space on both the inside and outside. This space can be used to stiffen the intermediate tank side plate 42. In this embodiment, as an example, the second tank space 62 between the intermediate tank side plate 42 and the outer tank side plate 52 is used to position a stiffening ring 87. In this way, the intermediate tank side plate 42 has a higher degree of freedom in reinforcement compared to the intermediate tank bottom plate 41, and can be flexibly adapted to provide the required rigidity. For example, the buoyancy force acting on the inner tank 3 varies depending on the size and shape of the inner tank 3, so appropriate stiffening can be designed for the intermediate tank side plate 42 by anticipating the load acting on the inner tank 3 (for example, the position and number of stiffening rings 87, the presence or absence of reinforcing ribs, the number of plate-shaped stiffening members connecting the stiffening rings 87, etc.). From this perspective, having the intermediate tank side plate 42 (and the support 8) function as a force transmission member between the first anchor strap 9 and the second anchor strap 10 is advantageous compared to having other elements of the intermediate tank 4 (for example, the intermediate tank bottom plate 41) perform that function.

[0038] [Summary] The multi-shell tank 1 relating to item 1 of this disclosure is The first tank 3 has a first tank bottom plate 31 and a cylindrical first tank side plate 32 that rises from the first tank bottom plate 31, and contains liquefied gas. A second tank 4 has a second tank bottom plate 41 positioned below the first tank bottom plate 31, and a cylindrical second tank side plate 42 that rises from the second tank bottom plate 41 and surrounds the first tank side plate 32 at a distance from each other. It is equipped with a first anchor strap 9 positioned between the first tank 3 and the second tank 4 at a distance of 61, and connecting the side plate 32 of the first tank and the side plate 42 of the second tank. In the above embodiment, the first tank corresponds to the inner tank 3, the first tank bottom plate to the inner tank bottom plate 31, the first tank side plate to the inner tank side plate 32, the second tank to the intermediate tank 4, the second tank bottom plate to the intermediate tank bottom plate 41, and the second tank side plate to the intermediate tank side plate 42. However, the connection structure between the first and second tanks of the multi-shell tank 1 according to the first item is not limited to application to the connection structure between the inner tank 3 and the intermediate tank 4, but may also be applied to the connection structure between the intermediate tank 4 and the outer tank 5. Furthermore, if the multi-shell tank 1 has multiple intermediate tanks 4 between the inner tank 3 and the outer tank 5, the connection structure between the first and second tanks of the multi-shell tank 1 according to the first item may also be applied to the connection structure between the first intermediate tank 4 and the second intermediate tank 4 surrounding it.

[0039] In the multi-shell tank 1 with the above configuration, when the first tank 3 attempts to float and an upward force acts on the first anchor strap 9, this upward force is transmitted directly from the first anchor strap 9 to the second tank side plate 42. In this embodiment, the upward force transmitted to the intermediate tank side plate 42 is then transmitted from the second tank side plate 42 to the tank foundation 7 via the second anchor strap 10. Since there is sufficient space (between the second tanks 62) on the outer circumference of the second tank side plate 42 for stiffening, the second tank side plate 42 has a greater degree of design freedom to increase its local rigidity compared to other parts of the second tank 4 (for example, the second tank bottom plate 41). Therefore, when an upward force acts on the first anchor strap 9 as described above, a large local stress is generated in the second tank side plate 42, but it is relatively easy to provide the second tank side plate 42 with sufficient rigidity to withstand that stress. Furthermore, the localized large stress generated in the second tank side plate 42 varies depending on the scale and structure of the multi-shell tank 1, as well as the contents of the first tank 3. However, by providing the second tank side plate 42 with rigidity sufficient to withstand the estimated stress, a support structure for the first tank 3 that can prevent the first tank 3 from floating up can be realized.

[0040] The multi-shell tank 1 according to the second item of this disclosure is the multi-shell tank 1 according to the first item, wherein the second tank side plate 42 has a support 8 that is joined to the second tank side plate 42 and protrudes toward the first tank side plate 32, and the support 8 has a joint portion 80 to which the lower end of the first anchor strap 9 is joined.

[0041] In the multi-shell tank 1 described above, the connecting portion 80 of the support 8 is closer to the first tank side plate 32 than to the second tank side plate 42. Therefore, compared to the case where the first anchor strap 9 is directly connected to the second tank side plate 42, the angle between the first tank side plate 32 and the first anchor strap 9 can be reduced. As a result, the first anchor strap 9 can efficiently transmit upward force, preventing the first tank 3 from floating up.

[0042] The multi-shell tank 1 according to the third item of this disclosure is the multi-shell tank 1 according to the second item, wherein the connecting portion 80 is located within the vertical height range between the second tank bottom plate 41 and the first tank bottom plate 31.

[0043] In the multi-shell tank 1 described above, the connecting portion 80 of the support 8 is positioned below the first tank bottom plate 31. Compared to the case where the connecting portion 80 of the support 8 is positioned above the first tank bottom plate 31, the angle between the first tank side plate 32 and the first anchor strap 9 can be reduced. As a result, the first anchor strap 9 can efficiently transmit upward force, preventing the first tank 3 from floating up.

[0044] The multi-shell tank 1 according to the fourth item of this disclosure is a multi-shell tank 1 according to the second or third item, wherein the support 8 has a frame-like structure in which a beam member 81, which protrudes from the second tank side plate 42 toward the first tank side plate 32 and has a connecting portion 80 arranged thereon, and a reinforcing member 82 arranged between the beam member 81 and the second tank side plate 42 are combined.

[0045] In this frame-shaped support 8A, when an upward force is applied to the first anchor strap 9, the protruding end 81b of the beam member 81 is pulled upward, but the reinforcing member 82 is compressed between the beam member 81 and the second tank side plate 42, suppressing the deformation of the beam member 81. Such a frame-shaped support 8A can have a simple structure and possess appropriate rigidity to prevent the first tank 3 from floating up.

[0046] In item 5 of this disclosure, the multi-shell tank 1 is a multi-shell tank 1 relating to item 2 or 3, in which the support 8 has a bracket shape.

[0047] Such a bracket-shaped support 8B can be easily constructed with a small number of parts. Furthermore, by providing appropriate stiffening, the bracket-shaped support 8B can have sufficient rigidity to prevent the first tank 3 from floating up.

[0048] The multi-shell tank 1 according to item 6 of this disclosure is a multi-shell tank 1 according to any of items 2 to 5, wherein the second tank side plate 42 has a stiffening member 87 that reinforces the rigidity of the portion to which the support 8 is joined.

[0049] The multi-shell tank 1 according to item 7 of this disclosure is the multi-shell tank 1 according to item 6, wherein the stiffening member 87 is a stiffening ring 87 that is continuous in the circumferential direction along the outer wall of the second tank side plate 42.

[0050] In the multi-shell tank 1 configuration relating to items 6 and 7, when the first tank 3 attempts to float and an upward force acts on the first anchor strap 9, a large localized stress is generated at the portion where the support 8 of the second tank side plate 42 is joined. However, the stiffening member 87 allows the second tank side plate 42 to have locally high rigidity capable of withstanding this stress.

[0051] The multi-shell tank 1 according to item 8 of this disclosure is a multi-shell tank 1 according to any of items 2 to 7, wherein a plurality of support members 8 are arranged at intervals along the inner wall of the second tank side plate 42, and further comprises a stiffening member 85 arranged between a pair of adjacent support members 8, which is joined to the second tank side plate 42 and the second tank bottom plate 41 to reinforce the rigidity of the second tank side plate 42.

[0052] In the multi-shell tank 1 with the above configuration, a large radially inward stress is locally generated at the joint between the second tank side plate 42 and the support 8. However, the rigidity of the second tank side plate 42 is increased by the stiffening member 85, thereby suppressing radially inward deformation of the second tank side plate 42. Furthermore, by positioning the stiffening member 85 in a position that overlaps vertically with the stiffening member (stiffening ring 87) located on the outer wall of the second tank side plate 42, buckling of the stiffening member (stiffening ring 87) can be prevented in addition to the second tank side plate 42.

[0053] The multi-shell tank 1 according to item 9 of this disclosure is a multi-shell tank 1 according to any of items 2 to 8, wherein a plurality of support members 8 are arranged at intervals along the inner wall of the second tank side plate 42, and a brace 86 is further provided that spans a pair of adjacent support members 8.

[0054] In the multi-shell tank 1 with the above configuration, the torsional rigidity of the support members 8 can be improved by connecting the adjacent support members 8 with braces 86.

[0055] The multi-shell tank 1 according to item 10 of this disclosure further comprises a tank foundation 7 located below the second tank bottom plate 41 and a second anchor strap 10 located on the outside of the second tank 4 and connecting the second tank side plate 42 and the tank foundation 7, in addition to the multi-shell tank 1 according to any of items 1 to 9.

[0056] The multi-shell tank 1 according to item 11 of this disclosure further comprises a third tank 5 having a third tank bottom plate 51 positioned between the second tank bottom plate 41 and the tank foundation 7, and a cylindrical third tank side plate 52 that rises from the third tank bottom plate 51 and surrounds the second tank side plate 42 at a distance from each other. In the above embodiment, the third tank corresponds to the outer tank 5, the third tank bottom plate corresponds to the outer tank bottom plate 51, and the third tank side plate corresponds to the outer tank side plate 52.

[0057] The discussions of this disclosure described above are presented for illustrative and explanatory purposes only and are not intended to limit the disclosure to the forms disclosed herein. For example, in the detailed description above, various features of the disclosure are grouped into a single embodiment for the purpose of streamlining the disclosure, but some of the features may be combined. Also, some of the features included in this disclosure may be combined into alternative embodiments, configurations, or aspects other than those discussed above. [Explanation of symbols]

[0058] 1: Multi-shell tank 3: Inner tank (1st tank) 4: Intermediate tank (second tank) 5: Outer tank (3rd tank) 7: Tank foundation 8:Support 8A: Frame-shaped support 8B: Bracket-shaped support 9: First anchor strap 10: Second anchor strap 31: Inner tank bottom plate (first tank bottom plate) 32: Inner tank side plate (first tank side plate) 36: 2nd bottom cold insulation layer 41: Intermediate tank bottom plate (second tank bottom plate) 42: Intermediate tank side plate (second tank side plate) 46: 1st bottom cold insulation layer 51: Outer tank bottom plate (3rd tank bottom plate) 52: Outer tank side plate (3rd tank side plate) 61: Between the 1st tanks 62: 2nd tank space 80:Joining part 81: Beam member 82: Reinforcement member 85: Stiffening member 86: Brace 87: Stiffening ring (stiffening member)

Claims

1. The first tank has a first tank bottom plate and a cylindrical first tank side plate that rises from the first tank bottom plate, A second tank having a second tank bottom plate positioned below the first tank bottom plate, and a cylindrical second tank side plate that rises from the second tank bottom plate and surrounds the first tank side plate at a distance from each other, The system includes a first anchor strap positioned between the first and second tanks, connecting the side plate of the first tank and the side plate of the second tank, The second tank side plate includes a support that is joined to the second tank side plate and protrudes toward the first tank side plate, and the support has a joint to which the lower end of the first anchor strap is joined. The connecting portion is located within the vertical height range between the second tank bottom plate and the first tank bottom plate. Multi-shell tank.

2. The support has a frame-like structure formed by combining a beam member, which protrudes from the second tank side plate toward the first tank side plate and has the connecting portion arranged thereon, and a reinforcing member arranged between the beam member and the second tank side plate. A multi-shell tank according to claim 1.

3. The support has a bracket shape, A multi-shell tank according to claim 1 or 2.

4. The second tank side plate has a stiffening member that reinforces the rigidity of the portion to which the support is joined. A multi-shell tank according to claim 1 or 2.

5. The first tank has a first tank bottom plate and a cylindrical first tank side plate that rises from the first tank bottom plate, A second tank having a second tank bottom plate positioned below the first tank bottom plate, and a cylindrical second tank side plate that rises from the second tank bottom plate and surrounds the first tank side plate at a distance from each other, The system includes a first anchor strap positioned between the first and second tanks, connecting the side plate of the first tank and the side plate of the second tank, The second tank side plate includes a support that is joined to the second tank side plate and protrudes toward the first tank side plate, and a stiffening ring that is continuous in the circumferential direction along the outer wall of the second tank side plate as a stiffening member that reinforces the rigidity of the portion to which the support is joined, and the support has a joint to which the lower end of the first anchor strap is joined. Multi-shell tank.

6. The first tank has a first tank bottom plate and a cylindrical first tank side plate that rises from the first tank bottom plate, A second tank having a second tank bottom plate positioned below the first tank bottom plate, and a cylindrical second tank side plate that rises from the second tank bottom plate and surrounds the first tank side plate at a distance from each other, The system includes a first anchor strap positioned between the first and second tanks, connecting the side plate of the first tank and the side plate of the second tank, The second tank side plate includes a support that is joined to the second tank side plate and protrudes toward the first tank side plate, and the support has a joint to which the lower end of the first anchor strap is joined. Multiple of the aforementioned supports are arranged at intervals along the inner wall of the second tank side plate. The structure further includes a stiffening member positioned between a pair of adjacent supports, which is joined to the second tank side plate and the second tank bottom plate to reinforce the rigidity of the second tank side plate. Multi-shell tank.

7. The first tank has a first tank bottom plate and a cylindrical first tank side plate that rises from the first tank bottom plate, A second tank having a second tank bottom plate positioned below the first tank bottom plate, and a cylindrical second tank side plate that rises from the second tank bottom plate and surrounds the first tank side plate at a distance from each other, The system includes a first anchor strap positioned between the first and second tanks, connecting the side plate of the first tank and the side plate of the second tank, The second tank side plate includes a support that is joined to the second tank side plate and protrudes toward the first tank side plate, and the support has a joint to which the lower end of the first anchor strap is joined. Multiple of the aforementioned supports are arranged at intervals along the inner wall of the second tank side plate, and the structure further comprises a brace stretched across a pair of adjacent supports. Multi-shell tank.

8. The first tank has a first tank bottom plate and a cylindrical first tank side plate that rises from the first tank bottom plate, A second tank having a second tank bottom plate positioned below the first tank bottom plate, and a cylindrical second tank side plate that rises from the second tank bottom plate and surrounds the first tank side plate at a distance from each other, A first anchor strap is positioned between the first tank and the second tank and connects the side plate of the first tank and the side plate of the second tank, The tank foundation is located beneath the second tank bottom plate, The second tank is provided with a second anchor strap positioned on the outside of the second tank and connecting the side plate of the second tank to the tank foundation, The second tank side plate includes a support that is joined to the second tank side plate and protrudes toward the first tank side plate, and the support has a joint to which the lower end of the first anchor strap is joined. The upper end of the second anchor strap is connected to the second tank side plate above the connection portion of the support. Multi-shell tank.

9. The third tank further comprises a third tank bottom plate positioned between the second tank bottom plate and the tank foundation, and a cylindrical third tank side plate that rises from the third tank bottom plate and surrounds the second tank side plate at a distance. The multi-shell tank according to claim 8.

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