Multi-layer tank and ship

Abstract

This multi-layer tank comprises: an inner tank that accommodates a liquified gas; an outer tank that surrounds the inner tank; and a dome which is joined to the inner tank and the outer tank and a section of which protrudes from the outer tank in a protrusion direction. The dome includes: a first middle part that is joined to the inner tank; a second middle part that is joined to the outer tank and that is disposed so as to be spaced apart from the first middle part in the protrusion direction; and a linking part that links the first middle part and the second middle part and that can elastically deform in conformance with relative displacement of the first middle part with respect to the second middle part. An inner circumferential space of the first middle part, an inner circumferential space of the linking part, and an inner circumferential space of the second middle part mutually communicate.

Description

Multi-hull tanks and ships

[0001] The present disclosure relates to a multi-shell tank and a vessel equipped therewith.

[0002] Multi-shell tanks have been known as containers for storing low-temperature liquids such as liquefied gas. These multi-shell tanks include an inner tank and at least one outer tank surrounded by the inner tank, with a thermal barrier layer between the tanks to prevent heat from entering the inner tank. Patent Document 1 discloses this type of multi-shell tank.

[0003] The double-shell tank disclosed in Patent Document 1 is installed on a liquefied gas carrier. This double-shell tank includes an inner tank and an outer tank. The inner tank has an inner tank body that stores liquefied gas and an inner tank dome that protrudes upward from the inner tank body. The outer tank has an outer tank body that surrounds the inner tank body and an outer tank dome that surrounds the inner tank dome. Penetrations for various pipes, such as liquefied gas transfer pipes and electrical pipes, are concentrated in the inner and outer tank domes. The inner and outer tank domes are connected by a connecting member, thereby connecting the inner and outer tanks.

[0004] JP 2015-4383 A

[0005] When the inner tank is completely surrounded by the outer tank as in Patent Document 1, the access route between the outside of the tank and the inside of the inner tank must pass through both the outer and inner tanks, and the inner tank cannot be opened until gas is purged between the inner and outer tanks. For these reasons, a multi-shell tank having an access route that does not pass between the inner and outer tanks is desired.

[0006] The present disclosure has been made in consideration of the above circumstances, and its purpose is to provide a multi-shell tank having an inner tank and an outer tank surrounding the inner tank, and equipped with a dome where piping and the like are concentrated, which can simplify the internal and external access routes.

[0007] In order to solve the above problems, a multi-shell tank according to one embodiment of the present disclosure comprises: an inner tank for containing liquefied gas; an outer tank surrounding the inner tank; and a dome joined to the inner tank and the outer tank, a portion of which protrudes from the outer tank in a protruding direction, wherein the dome has a first body joined to the inner tank, a second body positioned away from the first body in the protruding direction and joined to the outer tank, and a connecting part that connects the first body and the second body and is elastically deformable in response to relative displacement of the first body with respect to the second body, and the inner space of the first body, the inner space of the connecting part, and the inner space of the second body are connected to each other.

[0008] A vessel according to one aspect of the present disclosure includes a hull and the multi-shell tank supported by the hull.

[0009] According to the present disclosure, in a multi-shell tank having an inner tank and an outer tank surrounding the inner tank, and equipped with a dome where piping and the like are concentrated, the access routes inside and outside the tank can be simplified.

[0010] FIG. 1 is a schematic vertical cross-sectional view of a ship equipped with a multi-shell tank according to one embodiment of the present disclosure. FIG. 2 is an enlarged vertical cross-sectional view of the top of the multi-shell tank. FIG. 3 is an enlarged cross-sectional view of the top of the multi-shell tank according to Modification 1. FIG. 4 is a diagram illustrating the dimensions of each part of the connection part. FIG. 5 is an enlarged vertical cross-sectional view of the top of the multi-shell tank after deformation. FIG. 6 is an enlarged cross-sectional view of the top of the multi-shell tank showing the deformable portion according to Modification 1. FIG. 7 is an enlarged cross-sectional view of the top of the multi-shell tank showing the deformable portion according to Modification 2. FIG. 8 is an enlarged cross-sectional view of the top of the multi-shell tank showing the deformable portion according to Modification 3. FIG. 9 is an enlarged cross-sectional view of the top of the multi-shell tank showing the deformable portion according to Modification 4.

[0011] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In this specification, the term "inside" refers to the side closer to the center of the space inside the inner vessel 3 of the multi-shell tank 2, and the term "outside" refers to the side farther from the center of the space inside the inner vessel 3 of the multi-shell tank 2.

[0012] FIG. 1 is a schematic vertical cross-sectional view of a ship 1 equipped with a multi-shell tank 2 according to one embodiment of the present disclosure. As shown in FIG. 1, the ship 1 includes at least one multi-shell tank 2 and a hull 11 that supports the multi-shell tank 2. The multi-shell tank 2 contains a low-temperature liquefied gas. Examples of the liquefied gas include LNG, liquefied nitrogen, liquefied hydrogen, and liquefied helium. The ship 1 is a liquefied gas carrier that transports the liquefied gas. The multi-shell tank 2 according to this embodiment is a cargo tank that contains liquefied gas as cargo, but the multi-shell tank 2 may also be a fuel tank.

[0013] [General Configuration of Multi-shell Tank 2] The multi-shell tank 2 comprises an inner tank 3, an outer tank 4 surrounding the inner tank 3, and a dome 6 penetrating the inner tank 3 and the outer tank 4 in a protruding direction X. In this embodiment, the protruding direction X is the vertical direction. The multi-shell tank 2 according to this embodiment comprises a double tank consisting of the inner tank 3 and the outer tank 4, but the multi-shell tank 2 may comprise three or more tanks. The outer tank 4 is surrounded by a tank cover 12 covering the top and a retaining wall 14 covering the sides and bottom. A retaining space 53 between the outer tank 4 and the tank cover 12 / retaining wall 14 is filled with air or an inert gas. The top of the dome 6 protrudes above the tank cover 12 and is exposed.

[0014] The inner tank 3 is a container for storing liquefied gas and has a storage space 51 therein for storing the liquefied gas. A pipe tower 20 extending in the protruding direction X is disposed in the storage space 51. A pump 21 is disposed at the bottom of the pipe tower 20. The upper part of the pipe tower 20 is joined to the lower part of the dome 6. The top of the inner tank 3 is joined to an inner tank joint 61 of the dome 6. Furthermore, the top of the outer tank 4 is joined to an outer tank joint 62 of the dome 6. The outer tank joint 62 is located above the inner tank joint 61.

[0015] The inner tank 3 and the outer tank 4 are spaced apart in the radial direction of the multi-shell tank 2. An airtight inner / outer tank space 52 is formed between the inner tank 3 and the outer tank 4, and a thermal barrier layer made of a heat insulating material or the like is disposed between the inner and outer tanks 52. The space between the inner and outer tanks 52 is filled with an inter-tank gas. The inter-tank gas is, for example, a gas having a boiling point equal to or higher than the boiling point of the liquefied gas stored in the storage space 51. In this embodiment, the vaporized gas of the liquefied gas in the storage space 51 is used as the inter-tank gas. In this way, when the same gas is filled in the storage space 51 and between the inner and outer tanks 52, the space between the inner and outer tanks 52 may be connected to the space between the inner and outer tanks 52 in the inner tank 3.

[0016] [Configuration of the Top of the Multi-shell Tank 2] Figure 2 is an enlarged vertical cross-sectional view of the top of the multi-shell tank 2. As shown in Figure 2, the dome 6 has a first body 65, a second body 66, a roof 67, and a connecting portion 68.

[0017] The first body 65 has a cylindrical shape, and an inner tank joint 61 is provided on the first body 65. The inner tank 3 is joined to the inner tank joint 61, and movement of the first body 65 is restricted by the inner tank 3. The second body 66 has a cylindrical shape, and an outer tank joint 62 is provided on the second body 66. The outer tank 4 is joined to the outer tank joint 62, and movement of the second body 66 is restricted by the outer tank 4. The upper part of the second body 66 is closed by a roof 67. In this embodiment, the first body 65 and the second body 66 are cylindrical, but this is not limited thereto, and the first body 65 and the second body 66 may be cylindrical. The second body 66 is disposed above the first body 65, and the first body 65 and the second body 66 are spaced apart in the protruding direction X. The gap between the first body portion 65 and the second body portion 66 is in communication with the space between the inner and outer tanks 52 between the inner tank 3 and the outer tank 4 .

[0018] The connecting portion 68 connects the first body portion 65 and the second body portion 66 so as to allow relative displacement between the first body portion 65 restrained by the inner tank 3 and the second body portion 66 restrained by the outer tank 4. The entirety or a part of the connecting portion 68 is disposed inside the dome 6. The connecting portion 68 includes a first annular plate 71, a second annular plate 72, and a cylindrical body 73. The connecting portion 68 is interposed between the inner tank 3 and the outer tank 4, and transmits a load between the inner tank 3 and the outer tank 4.

[0019] The first annular plate 71 is a hollow circular flat plate having an outer diameter substantially the same as or slightly smaller than that of the first body 65. The first annular plate 71 has a main surface that is approximately perpendicular to the protruding direction X when the first annular plate 71 is not deformed. The outer edge of the first annular plate 71 is joined to the upper end of the first body 65. The outer edge of the first annular plate 71 may be joined to the inner circumferential surface of the first body 65. Since the movement of the first body 65 is restrained by the inner tank 3, the movement of the outer edge of the first annular plate 71 is also restrained by the inner tank 3.

[0020] The second annular plate 72 is a hollow circular flat plate having an outer diameter substantially the same as or slightly smaller than that of the second body 66. The second annular plate 72 has a main surface that is approximately perpendicular to the protruding direction X when the second annular plate 72 is not deformed. The outer edge of the second annular plate 72 is joined to the inner circumferential surface of the second body 66. The outer edge of the second annular plate 72 may also be joined to the lower end of the second body 66. Since the movement of the second body 66 is restrained by the outer tank 4, the movement of the outer edge of the second annular plate 72 is also restrained by the outer tank 4.

[0021] The first annular plate 71 and the second annular plate 72 are spaced apart in the protruding direction X. In the example shown in Fig. 2, the first body portion 65 and the second body portion 66 have substantially the same outer diameter, and therefore the first annular plate 71 and the second annular plate 72 have substantially the same outer diameter. However, the outer diameters of the first body portion 65 and the second body portion 66 may be different, and the outer diameters of the first annular plate 71 and the second annular plate 72 may be different from each other.

[0022] The cylindrical body 73 is a cylindrical member extending in the protruding direction X. The outer diameter of the cylindrical body 73 is smaller than the inner diameters of the first body portion 65 and the second body portion 66, and the cylindrical body 73 is disposed inside the first body portion 65 and the second body portion 66. The outer diameter of the cylindrical body 73 is substantially the same as the inner diameters of the first annular plate 71 and the second annular plate 72. The inner edge portions of the first annular plate 71 and the second annular plate 72, which are spaced apart in the protruding direction X, are connected by the cylindrical body 73.

[0023] As described above, the connecting portion 68 formed by the first annular plate 71, the cylindrical body 73, and the second annular plate 72 has a C-shaped cross section parallel to the protruding direction X that opens outward. By providing the connecting portion 68 with such a shape, the connecting portion 68 has a reduced radial dimension and is provided with higher elastic deformability. However, the outer diameter of the first annular plate 71 and the inner diameter of the second annular plate 72 may be substantially the same, the cylindrical body 73 may connect the outer edge of the first annular plate 71 and the inner edge of the second annular plate 72, and the first annular plate 71, the cylindrical body 73, and the second annular plate 72 may form the connecting portion 68 with a crank-shaped cross section parallel to the protruding direction X. Alternatively, the connecting portion 68 may be configured such that the inner diameter of the first annular plate 71 and the outer diameter of the second annular plate 72 are substantially the same, the inner edge of the first annular plate 71 and the outer edge of the second annular plate 72 are connected by the cylindrical body 73, and the first annular plate 71, the cylindrical body 73, and the second annular plate 72 form the connecting portion 68 having a crank-shaped cross section parallel to the protrusion direction X.

[0024] The upper end of the cylindrical body 73 is joined to the inner edge of the second annular plate 72, and the lower end of the cylindrical body 73 is joined to the inner edge of the first annular plate 71. In this way, the cylindrical body 73, the first annular plate 71, and the second annular plate 72 are joined so as to be approximately perpendicular to each other in the vertical cross section of the multi-shell tank 2. However, the corners of the connection portions of the cylindrical body 73, the first annular plate 71, and the second annular plate 72, or both, may be rounded.

[0025] In a modified example of the multi-shell tank 2 shown in FIG. 3 , the cylindrical body 73 and the first annular plate 71 are connected via a ring member 70 having an arc-shaped vertical cross section. This provides a smooth curved cross section in the protruding direction X of the connection between the cylindrical body 73 and the first annular plate 71, thereby suppressing stress concentration at the connection. Similarly, the cylindrical body 73 and the second annular plate 72 are connected via a ring member 70 having an arc-shaped cross section in the protruding direction X. This provides a smooth curved cross section in the protruding direction X of the connection between the cylindrical body 73 and the second annular plate 72, thereby suppressing stress concentration at the connection. Note that in the example shown in FIG. 3 , the first annular plate 71 and the first body 65 are connected via a ring member 70 having an arc-shaped cross section in the protruding direction X. In this manner, the corners of the connection between the connecting portion 68 and the first body 65 or the second body 66 may also be rounded.

[0026] 2 , the first annular plate 71 is disposed between the inner tank joint 61 and the outer tank joint 62 in the protruding direction X. As a result, an outer peripheral space 74 of the cylindrical body 73 surrounded by the first annular plate 71, the second annular plate 72, and the cylindrical body 73 is in communication with the space between the inner and outer tanks 52. In addition, in this embodiment, the second annular plate 72 is disposed farther away from the inner tank joint 61 in the protruding direction X than the outer tank joint 62. As a result, the outer peripheral space 74 of the cylindrical body 73 has a region separated from the exposed or retained space 53 only by the second body portion 66 of the dome 6.

[0027] The outer peripheral space 74, which is connected to the space between the inner and outer tanks 52, can be used as a wiring space for the inter-tank piping 92 (or inter-tank wiring) that passes through the space between the inner and outer tanks 52. As shown in FIG. 1 , the inter-tank piping 92 is led from the space between the inner and outer tanks 52 to the outer peripheral space 74 of the cylindrical body 73 and then led to the exposed area through a penetration in the second body 66 of the dome 6. In other words, the inter-tank piping 92 is led directly to the exposed area through the space between the inner and outer tanks 52 and the space connected to the space between the inner and outer tanks 52, without passing through the storage space 51 or the holding space 53. Note that the penetration in the dome 6 through which the inter-tank piping 92 passes may be subjected to airtight construction to ensure airtightness between the inner and outer tanks 52 and heat insulation construction similar to that of the tanks. Instead of or in addition to the inter-tank piping 92, inter-tank wiring may be installed similarly to the inter-tank piping 92. Furthermore, inside the dome 6, the inner circumferential space of the first body 65, the inner circumferential space of the connecting portion 68, and the inner circumferential space of the second body 66 (excluding the portion where the connecting portion 68 is located on the inner circumferential side) are connected to each other, forming a space extending in the protruding direction X. The intra-tank piping 91 passed through the pipe tower 20 is passed through a space extending in the protruding direction X inside the dome 6, which is connected to the pipe tower 20, and penetrates the second body 66 or the roof portion 67 of the dome 6 to be led to the exterior. Instead of or in addition to the intra-tank piping 91, intra-tank wiring may be laid similarly to the intra-tank piping 91. In this way, the penetrations of the intra-tank piping 91 and the inter-tank piping 92 are arranged together in the dome 6, and each of the intra-tank piping 91 and the inter-tank piping 92 is led out of the tank through a single penetration located in the dome 6.

[0028] Returning to FIG. 2 , the cylindrical body 73 includes a first cylindrical portion 731, a second cylindrical portion 732, and a deformable portion 7 disposed between the first cylindrical portion 731 and the second cylindrical portion 732. The deformable portion 7 is elastically deformable in response to relative displacement of the second cylindrical portion 732 relative to the first cylindrical portion 731. The deformable portion 7 is configured by a combination of multiple ring plates 7a or a combination of a ring plate 7a and a third cylindrical portion 7b. The ring plate 7a is a hollow, circular, flat member having a main surface substantially perpendicular to the protruding direction X when undeformed. The third cylindrical portion 7b is a cylindrical member extending substantially parallel to the protruding direction X. The thinner the ring plate 7a, the more flexible the ring plate 7a is, but the ring plate 7a must have a thickness sufficient to transmit a load. The ring plate 7a and the third cylindrical portion 7b each have a thickness of, for example, 10 mm to 60 mm. The cylindrical body 73 including such a deformable portion 7 can still transmit a load between the first annular plate 71 and the second annular plate 72 .

[0029] The deformable portion 7 is composed of a pair of ring plates 7a spaced apart in the protruding direction X, and a third cylindrical portion 7b connecting the pair of ring plates 7a in the protruding direction X. Inner edge portions of the pair of ring plates 7a are joined to the cylindrical body 73. Outer edge portions of the pair of ring plates 7a are joined to the third cylindrical portion 7b. Preferably, the pair of ring plates 7a are joined together with the third cylindrical portion 7b sandwiched between them.

[0030] The arrangement of the deformable portion 7 in the cylindrical body 73 is not particularly limited, but it is desirable that the joints of the members not be extremely close to each other. As shown in FIG. 4 , the first end 73 a of the cylindrical body 73 joined to the first annular plate 71 is separated from the deformable portion 7 by a distance H1 in the protruding direction X. H1 is a value that does not cause the joint between the first annular plate 71 and the cylindrical body 73 to be narrow, and is not particularly limited, but is 500 mm or more. The second end 73 b of the cylindrical body 73 joined to the second annular plate 72 is separated from the deformable portion 7 by a distance H2 in the protruding direction X. H2 is a value that does not cause the joint between the second annular plate 72 and the cylindrical body 73 to be narrow, and is not particularly limited, but is 500 mm or more.

[0031] The dimension of the third cylindrical portion 7b in the protruding direction X, i.e., the distance between the pair of ring plates 7a, is H3. H3 is a value that prevents the joint between the ring plates 7a and the third cylindrical portion 7b from becoming narrow, and is not particularly limited, but is preferably 500 mm or more.

[0032] The greater the difference between the outer diameter and the inner diameter of the ring plate 7a, the greater the flexibility of the ring plate 7a. However, to prevent an extremely narrow portion from being present in the outer peripheral space 74 of the cylindrical body 73, the outer wall of the cylindrical body 73 including the deformable portion 7 and the inner wall of the second body portion 66 of the dome 6 are radially spaced apart by R1. When the deformable portion 7 protrudes radially outward from the dome 6 beyond other portions of the cylindrical body 73, the maximum diameter of the cylindrical body 73 is the outer diameter of the ring plate 7a of the deformable portion 7. R1 is a value that prevents the outer peripheral space 74 of the cylindrical body 73 from becoming extremely narrow and allows for the passage of workers, piping, and wiring, and is not particularly limited, but is preferably 500 mm or greater.

[0033] In the multi-shell tank 2 configured as described above, when liquefied gas is stored in the storage space 51 of the inner tank 3, the inner tank 3 and the outer tank 4 contract due to the cold heat. Here, the inner tank 3 is at a lower temperature than the outer tank 4, and therefore the inner tank 3 thermally contracts to a greater extent than the outer tank 4. As a result, a relative displacement occurs between the inner tank joint 61 to which the inner tank 3 is joined in the dome 6 and the outer tank joint 62 to which the outer tank 4 is joined. Figure 5 shows the relative displacement caused by thermal contraction between the inner tank joint 61 and the outer tank joint 62. Note that the deformation of the connecting portion 68 and the inner tank 3 is exaggerated.

[0034] 5, when the inner tank 3 and the outer tank 4 thermally shrink, the gap between the inner tank joint 61, which is constrained by the inner tank 3, and the outer tank joint 62, which is constrained by the outer tank 4, increases. Accordingly, the connecting portion 68 of the dome 6 extends as a whole in the protruding direction X, absorbing the stress caused by the relative displacement between the inner tank joint 61 and the outer tank joint 62. In detail, of the connecting portion 68, mainly the first annular plate 71, the second annular plate 72, and the ring plate 7a of the cylindrical body 73 each elastically deform so that the outer edge and the inner edge move apart in the protruding direction X, causing the connecting portion 68 to extend as a whole in the protruding direction X.

[0035] The configuration of the deformable portion 7 of the cylindrical body 73 is not limited to the above, and may be any configuration that allows the cylindrical body 73 to be extended in the protruding direction X by elastic deformation. Modified examples of the cylindrical body 73 will be described below.

[0036] (Variation 1) The deformable portion 7 of the cylindrical body 73 shown in FIG. 2 protrudes outward from the main body of the cylindrical body 73. However, the deformable portion 7 may protrude inward from the main body of the cylindrical body 73. The deformable portion 7 of the cylindrical body 73 according to a variation shown in FIG. 6 includes a pair of ring plates 7a whose outer peripheries are joined to the cylindrical body 73, and a third cylindrical portion 7b connecting the inner peripheries of the pair of ring plates 7a. The inner diameter of the cylindrical body 73 including the deformable portion 7 is a value that allows the inner circumference of the cylindrical body 73 to be accommodated without narrowing and allows the pump 21, piping, and wiring to pass through. It is not particularly limited, but is preferably 1000 mm or greater. In the example shown in FIG. 6, the smallest diameter of the cylindrical body 73 is the inner diameter of the ring plate 7a of the deformable portion 7, and the ring plate 7a has an inner diameter of 1000 mm or greater.

[0037] (Variation 2) The cylindrical body 73 shown in Fig. 2 has one deformable portion 7, but may have multiple deformable portions 7 spaced apart in the protruding direction X. The cylindrical body 73 according to a variation shown in Fig. 7 has two deformable portions 7. The two deformable portions 7 are spaced apart by H4 in the protruding direction X. H4 is a value that ensures that the joint between the ring plate 7a and the main body of the cylindrical body 73 does not become narrow, and is not particularly limited, but is 500 mm or more.

[0038] (Variation 3) The deformable portion 7 of the cylindrical body 73 shown in Fig. 2 is composed of a pair of ring plates 7a and a third cylindrical portion 7b, but the third cylindrical portion 7b may be omitted. The deformable portion 7 of the cylindrical body 73 according to a variation shown in Fig. 8 is composed of a pair of ring plates 7a whose inner edges are joined together. The outer edges of the pair of ring plates 7a are both joined to the main body of the cylindrical body 73. However, the deformable portion 7 may also be composed of a pair of ring plates 7a whose outer edges are joined together.

[0039] (Variation 4) The deformable portion 7 of the cylindrical body 73 shown in Fig. 2 is composed of a pair of ring plates 7a and a third cylindrical portion 7b, but it is sufficient that the deformable portion 7 is capable of transmitting load and capable of elastically expanding and contracting deformation in the protruding direction X. The deformable portion 7 of the cylindrical body 73 according to a variation shown in Fig. 9 is a ridge 7c whose cross section in the protruding direction X is curved and which protrudes inward or outward beyond the first cylindrical portion 731 and the second cylindrical portion 732. The ridge 7c is continuous in the circumferential direction on the surface of the cylindrical body 73. The cross section of the ridge 7c may be wave-shaped, and the deformable portion 7 may be composed of, for example, a corrugated pipe.

[0040] [Summary] The multi-shell tank 2 according to the first item of the present disclosure comprises: an inner tank 3 for accommodating liquefied gas; an outer tank 4 surrounding the inner tank 3; and a dome 6 joined to the inner tank 3 and the outer tank 4, with a portion thereof protruding from the outer tank 4 in a protruding direction X. The dome 6 has a first body 65 joined to the inner tank 3, a second body 66 disposed apart from the first body 65 in the protruding direction X and joined to the outer tank 4, and a connecting part 68 connecting the first body 65 and the second body 66 and elastically deformable in response to a relative displacement of the first body 65 with respect to the second body 66, and the inner spaces of the first body 65, the connecting part 68, and the second body 66 are connected to each other.

[0041] The multi-shell tank 2 according to the second item of the present disclosure is the multi-shell tank 2 according to the first item, wherein the connecting portion 68 includes a first annular plate 71 having an outer edge joined to the first body 65, a second annular plate 72 having an outer edge joined to the second body 66 and positioned away from the first annular plate 71 in the protruding direction X, and a cylindrical body 73 having a first end 73a connected to the inner edge of the first annular plate 71 and a second end 73b connected to the inner edge of the second annular plate 72, and extending in the protruding direction X.

[0042] In the multi-shell tank 2 according to the first and second aspects, the inner tank 3 and the outer tank 4 are connected via the dome 6, so that a portion of the dome 6 is not enclosed by the outer tank 4. Therefore, by accessing the inner tank 3 through the wall of the dome 6 rather than through the wall of the outer tank 4, a simple internal / external access route can be realized that does not pass through the space between the inner and outer tanks 52. Furthermore, in the multi-shell tank 2 configured as described above, a space extending in the protruding direction X is formed on the inner periphery of the first body 65, the connecting portion 68, and the connecting portion 68. This space can be used for wiring or piping within the dome 6. Piping or wiring passed through the dome 6 can be led out to the open air by penetrating the roof portion 67 or the second body 66 of the dome 6, so a simple piping or wiring route with a reduced number of penetrations can be formed. Furthermore, in the multi-shell tank 2 having the above-described configuration, when the inner tank 3 contains low-temperature liquefied gas and the degree of thermal contraction between the inner tank 3 and the outer tank 4 differs, causing the inner tank 3 to be displaced relative to the outer tank 4, the stress caused by the relative displacement is suppressed by the elastic deformation of mainly the first annular plate 71 and the second annular plate 72 of the connecting portion 68.

[0043] The multi-shell tank 2 according to the third item of the present disclosure is the multi-shell tank 2 according to the second item, wherein the cylindrical body 73 includes a first cylindrical portion 731 and a second cylindrical portion 732 spaced apart in the protrusion direction X, and a deformation-permitting portion 7 that is elastically deformable in response to the relative displacement of the second cylindrical portion 732 relative to the first cylindrical portion 731.

[0044] In the multi-shell tank 2 having the above-described configuration, when the inner tank 3 is displaced relative to the outer tank 4, the connecting portion 68 is deformed in accordance with the relative displacement of the inner tank 3 relative to the outer tank 4 due to the elastic deformation of the first annular plate 71 and the second annular plate 72 and the elastic deformation of the deformation-permitting portion 7. Increasing the number of elastically deforming portions in the connecting portion 68 allows the connecting portion 68 to be elastically deformed to a greater extent and with greater flexibility.

[0045] The multi-shell tank 2 according to the fourth item of the present disclosure is the multi-shell tank 2 according to the third item, wherein the deformation-permitting portion 7 includes a pair of ring plates 7a spaced apart in the protrusion direction X and a third tubular portion 7b connecting the pair of ring plates 7a.

[0046] The multi-shell tank 2 according to the fifth item of the present disclosure is the multi-shell tank 2 according to the third item, wherein the deformation-permitting portion 7 includes a pair of ring plates 7a whose outer edges or inner edges are joined together.

[0047] The multi-shell tank 2 according to the sixth item of the present disclosure is the multi-shell tank 2 according to the third item, in which the deformable portion 7 has a curved cross section in the protrusion direction X and includes a protrusion 7c that continues circumferentially on the surface of the cylindrical body 73.

[0048] According to the multi-shell tank 2 according to the fourth to sixth aspects, the deformable portion 7 capable of transmitting the load in the cylindrical body 73 can be simply configured.

[0049] The multi-shell tank 2 according to the seventh item of the present disclosure is a multi-shell tank 2 according to any one of the second to sixth items, in which the corners of the connection between at least one of the first annular plate 71 and the second annular plate 72 and the cylindrical body 73 are rounded.

[0050] The multi-shell tank 2 according to the eighth item of the present disclosure is the multi-shell tank 2 according to the seventh item, in which the annular plate and the cylindrical body 73 are connected via a ring member 70 having a curved cross section in the protruding direction X.

[0051] According to the multi-shell tank 2 relating to the seventh and eighth items, stress concentration at the connection portions between the annular plates 71, 72 and the cylindrical body 73 can be suppressed.

[0052] The multi-shell tank 2 according to the ninth item of the present disclosure is the multi-shell tank 2 according to any one of the second to eighth items, which has an outer peripheral space 74 between the inner wall of the second body 66 and the outer wall of the cylindrical body 73, the outer peripheral space 74 being connected to the space between the inner and outer tanks 52 between the inner tank 3 and the outer tank 4.

[0053] In this way, by providing a space inside the dome 6 that is connected to the space between the inner and outer tanks 52, i.e., the outer peripheral space 74, it becomes possible to access the space between the inner and outer tanks 52 through the wall of the dome 6 without passing through the wall of the outer tank 4.

[0054] The multi-shell tank 2 according to the tenth item of the present disclosure is the multi-shell tank 2 according to the ninth item, wherein the second body 66 has a penetration portion that connects the outer peripheral space 74 with the exposed surface, and is provided with an inner and outer tank space 52, the outer peripheral space 74, and an inter-tank piping 92 that passes through the penetration portion.

[0055] In the multi-shell tank 2, the inter-vessel piping 92 can be extended to the open air through the penetration in the wall of the dome 6 without passing through the wall of the outer vessel 4.

[0056] The multi-shell tank 2 according to the eleventh item of the present disclosure is the multi-shell tank 2 according to the ninth or tenth item, in which the inner wall of the second body 66 and the outer wall of the cylindrical body 73 are spaced apart to allow workers to access the outer peripheral space 74.

[0057] In the multi-shell tank 2, the outer peripheral space 74 can be used as a passageway for workers.

[0058] The multi-shell tank 2 according to the twelfth item of the present disclosure is the multi-shell tank 2 according to any one of the second to eleventh items, further comprising a pipe tower 20 disposed in the inner tank 3 and connected to the lower part of the dome 6, and a pump 21 disposed at the lower part of the pipe tower 20, and the cylindrical body 73 has an inner diameter that allows the pump 21 to pass through.

[0059] In the multi-shell tank 2, the pump 21 can be carried in and out to the lower part of the pipe tower 20 through the dome 6.

[0060] A vessel 1 according to a thirteenth item of the present disclosure includes a hull 11 and a multi-shell tank 2 according to any one of the first to twelfth items supported by the hull 11.

[0061] The above-mentioned multi-shell tank 2 is suitable as a cargo tank or a fuel tank to be installed on a ship 1.

[0062] The foregoing discussion of the present disclosure has been presented for purposes of illustration and description and is not intended to limit the present disclosure to the form disclosed herein. For example, in the foregoing detailed description, various features of the present disclosure are grouped together in a single embodiment for the purpose of streamlining the disclosure, but some of the features may also be combined. Furthermore, the features included in the present disclosure may be combined into alternative embodiments, configurations, or aspects other than those discussed above.

Claims

1. an inner tank for containing liquefied gas; An outer tank surrounding the inner tank; a dome joined to the inner tank and the outer tank, a portion of which protrudes from the outer tank in a protruding direction; the dome has a first body portion joined to the inner tank, a second body portion disposed away from the first body portion in the protruding direction and joined to the outer tank, and a connecting portion connecting the first body portion and the second body portion and elastically deformable in response to a relative displacement of the first body portion with respect to the second body portion, and an inner circumferential space of the first body portion, an inner circumferential space of the connecting portion, and an inner circumferential space of the second body portion are in communication with each other. Multi-hull tank.

2. the connecting portion includes a first annular plate having an outer edge portion joined to the first body portion, a second annular plate having an outer edge portion joined to the second body portion and disposed away from the first annular plate in the protruding direction, and a tubular body having a first end portion connected to an inner edge portion of the first annular plate and a second end portion connected to an inner edge portion of the second annular plate and extending in the protruding direction.

2. The multi-shell tank of claim 1.

3. The cylindrical body includes a first cylindrical portion and a second cylindrical portion arranged apart from each other in the protruding direction, and a deformation allowing portion that is elastically deformable in response to a relative displacement of the second cylindrical portion with respect to the first cylindrical portion.

3. The multi-shell tank according to claim 2.

4. The deformation allowing portion includes a pair of ring plates arranged apart from each other in the protruding direction, and a third cylindrical portion connecting the pair of ring plates.

4. The multi-shell tank according to claim 3.

5. The deformation-allowing portion includes a pair of ring plates whose outer edges or inner edges are joined together, 4. The multi-shell tank according to claim 3.

6. The deformable portion has a curved cross section in the protruding direction and includes a protrusion that is continuous in a circumferential direction on a surface of the cylindrical body.

4. The multi-shell tank according to claim 3.

7. A corner of a connection portion between at least one of the first annular plate and the second annular plate and the cylindrical body is rounded.

4. A multi-shell tank according to claim 2 or 3.

8. The annular plate and the cylindrical body are connected via a ring member having a curved cross section in the protruding direction.

8. The multi-shell tank of claim 7.

9. An outer circumferential space is provided between the inner wall of the second body and the outer wall of the cylindrical body, the outer circumferential space being in communication with the inner and outer tanks of the inner tank and the outer tank.

4. A multi-shell tank according to claim 2 or 3.

10. The second body portion has a through portion that communicates the outer peripheral space with the exterior, The tank-to-tank piping is provided between the inner and outer tanks, through the outer peripheral space, and through the through-hole.

10. The multi-shell tank of claim 9.

11. The inner wall of the second body and the outer wall of the cylindrical body are spaced apart to allow an operator to access the outer circumferential space.

10. The multi-shell tank of claim 9.

12. a pipe tower disposed in the inner tank and connected to a lower portion of the dome; and a pump disposed at a lower portion of the pipe tower. The cylindrical body has an inner diameter through which the pump can pass.

4. A multi-shell tank according to claim 2 or 3.

13. The hull and and a multi-shell tank according to claim 1 or 2 supported on the hull. ship.