Liquefied gas tank

Abstract

A liquefied gas tank is provided with: an inner tank for accommodating liquefied gas; an outer tank surrounding the inner tank; and a cylindrical pipe tower having a main body part having a lower end joined to the bottom wall in the inner tank, a head part positioned above the outer tank, and a connection part penetrating the inner tank and the outer tank and connecting the main body part and the head part in the vertical direction, the pipe tower extending in the vertical direction from the bottom wall of the inner tank. The connecting part of the pipe tower has a cylindrical body extending in the vertical direction and having an inner groove joining part to which the top of the inner groove is joined and an outer groove joining part to which the top of the outer groove is joined, and a first deformation permitting part connecting the cylindrical body and the upper end of the main body part. And allows displacement of the main body portion with respect to the cylinder by elastic deformation.

Description

Technical Field

[0001] The present disclosure relates to a liquefied gas tank having a multi-layer shell structure with a tube tower. Background Art

[0002] In the past, there are known liquefied gas tanks for storing low-temperature liquefied gases such as liquefied hydrogen and liquefied natural gas. When such a liquefied gas tank is carried on a ship as a cargo tank, for example, there is a cylindrical pipe tower extending from the inside of the liquefied gas tank in the up-down direction. The lower end of the pipe tower is connected to the bottom of the tank. The upper part of the pipe tower penetrates the tank and protrudes above the tank, and the upper wall surface of the pipe tower is connected to the tank. Inside the pipe tower, there are loading and unloading pipes, injection pipes, liquid level gauges, electrical wiring, ladders for work, etc.

[0003] In the liquefied gas tank, there will be thermal contraction caused by loading liquefied gas, deformation caused by the weight of the liquefied gas, deformation (vibration) caused by the vibration of the hull, etc. The pipe tower is also deformed for the same reason, but there is a difference between the deformation of the liquefied gas tank and the deformation of the pipe tower. Therefore, as shown in Patent Document 1, in the previous liquefied gas tank, the lower end of the pipe tower is connected to the bottom of the tank by a lower cylindrical body with a larger diameter than the pipe tower. The lower end of the side plate of the lower cylindrical body is combined with the bottom of the tank, and the upper plate of the lower cylindrical body is combined with the lower end of the pipe tower. Moreover, the upper plate of the lower cylindrical body is deformed in the up and down direction, thereby absorbing the difference in deformation between the tank and the pipe tower, ensuring that high stress is not generated at the joint between the pipe tower and the tank.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent No. 3938591 Summary of the invention

[0007] Problems to be solved by the invention

[0008] Among liquefied gas tanks, there are structures that are made into multi-layer shell structures to improve thermal insulation performance. The liquefied gas tank with a multi-layer shell structure has an inner tank for storing liquefied gas and an outer tank surrounding the inner tank, and a thermal insulation layer is formed between the inner tank and the outer tank. A pipe tower is also provided in such a liquefied gas tank with a multi-layer shell structure. However, there is a tendency for liquefied gas tanks with a multi-layer shell structure to be larger, and in addition, the pipe tower penetrates the inner tank and the outer tank and protrudes above the tank, so the pipe tower is high in the vertical direction, and the weight of the pipe tower as a whole is also increased.

[0009] In the conventional liquefied gas tank, when setting up the pipe tower, first, the lower cylinder is fixed to the bottom wall of the inner tank, then the upper plate of the lower cylinder is supported from the inside by a jack, and the bottom wall of the inner tank supporting the jack is reinforced, and then the pipe tower is placed on the upper plate of the lower cylinder, and the lower cylinder is welded to the inner tank and the outer tank. In this way, in order to suppress the deflection of the upper plate of the lower cylinder, the setting operation of the liquefied gas tank becomes complicated. Moreover, in the multi-layer shell structure, the weight of the pipe tower applied to the lower cylinder is greater than that of the single shell structure, so the supporting force required to suppress the deflection of the upper plate of the lower cylinder becomes larger.

[0010] The present disclosure has been made in view of the above circumstances, and an object of the present disclosure is to provide a liquefied gas tank of a multilayer shell structure having a tube tower and achieving a simplified installation process of the tube tower.

[0011] Means for solving problems

[0012] The cam is an assembly of a plurality of flange adapters, each of which has a plurality of flange adapters, and a plurality of flange adapters, wherein the plurality of flange adapters have respective flanges, and the plurality of flanges have respective flanges.

[0013] Effects of the Invention

[0014] According to the present disclosure, it is possible to provide a liquefied gas tank having a multilayer shell structure that includes a tube tower and simplifies the installation process of the tube tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a vertical cross-sectional view of a liquefied gas tank according to an embodiment of the present disclosure.

[0016] Figure 2 It is a vertical cross-sectional view of a liquefied gas tank according to an embodiment showing a modified example of the lower portion of the tube tower.

[0017] Figure 3 It is an enlarged vertical cross-sectional view of the upper portion of the liquefied gas tank according to the embodiment.

[0018] Figure 4 It is a diagram illustrating the structure of an assembly.

[0019] Figure 5 It is a diagram for explaining the joining method of the connection part.

[0020] Figure 6 It is a diagram for explaining the joining method of the connection part.

[0021] Figure 7 This is a diagram for explaining how to install a tube tower.

[0022] Figure 8 This is an enlarged vertical cross-sectional view of the upper portion of the liquefied gas tank according to the embodiment showing a state in which the inner tank and the tube tower have been thermally shrunk.

[0023] Fig. 9 It is a vertical cross-sectional view of the liquefied gas tank of Modification Example 1.

[0024] Fig.10 It is a vertical cross-sectional view of the liquefied gas tank of Modification Example 1.

[0025] Fig.11 It is a vertical cross-sectional view of the liquefied gas tank of Modification Example 2.

[0026] Fig.12 This is an enlarged vertical sectional view of the upper portion of the liquefied gas tank of Modification Example 2.

[0027] Fig.13 This is an enlarged vertical cross-sectional view of the upper portion of the liquefied gas tank according to Modification 2, showing a state in which the inner tank and the tube tower have thermally shrunk. DETAILED DESCRIPTION

[0028] Next, embodiments of the present disclosure will be described with reference to the drawings. Figure 1 This is a vertical cross-sectional view of a liquefied gas tank 1 according to one embodiment of the present disclosure. Figure 1 The liquefied gas tank 1 shown is a cryogenic container for storing low-temperature liquefied gas such as liquefied hydrogen and liquefied natural gas. The liquefied gas tank 1 is supported on a base by means of a skirt. The base is, for example, the hull of a liquefied gas transport ship. However, the liquefied gas tank 1 to which the present disclosure is applied is not limited to a loading and unloading tank mounted on a ship, and any cryogenic container can be configured with a pipe tower inside the tank.

[0029] The liquefied gas tank 1 is a spherical tank. However, the liquefied gas tank 1 is not limited to a spherical tank, and may be a deformed spherical tank in the shape of an oblate ellipsoid, an extended tank with a cylindrical portion in between the upper and lower hemispheres, or a rectangular parallelepiped square tank. The liquefied gas tank 1 has an inner tank 31 for storing liquefied gas and an outer tank 32 surrounding the inner tank 31. The wall of the inner tank 31 is separated from the wall of the outer tank 32, and the groove between the inner tank 31 and the outer tank 32 becomes a heat insulation layer 33. The heat insulation layer 33 can be filled with a heat insulation material, or the heat insulation layer 33 can be a vacuum heat insulation layer.

[0030] A pipe tower 4 extending in the up-down direction is provided at the approximate center of the liquefied gas tank 1. Inside the pipe tower 4, there are arranged a loading and unloading pipe for loading or discharging liquefied gas relative to the interior of the inner tank 31, and an injection pipe for passing the liquefied gas extracted from the inner tank 31 for precooling the inner tank 31. The loading and unloading pipe and the injection pipe are provided in a state of being suspended from the upper part of the pipe tower 4. Inside the pipe tower 4, a loading and unloading pump is provided at the lower end of the loading and unloading pipe, and a injection pump is provided at the lower end of the injection pipe. In addition, a liquid level gauge, electrical wiring, etc. are also provided in the pipe tower 4. In addition, a ladder is provided inside the pipe tower 4 for an operator to enter the interior of the liquefied gas tank 1 from the upper part of the pipe tower 4.

[0031] The tube tower 4 includes a main body 41 , a head 42 , and a connection portion 44 . The connection portion 44 is disposed between the main body 41 and the head 42 in the up-down direction, and connects the main body 41 and the head 42 .

[0032] The main body 41 is a cylindrical body extending in the vertical direction. The lower end of the main body 41 is connected to the bottom wall of the inner groove 31 inside the inner groove 31. The outer diameter of the main body 41 is substantially constant in the vertical direction. Figure 2 As shown, the main body 41 may be integrally connected to the lower part of the cylinder in a truncated cone. The lower end of the main body 41 is rigidly connected to the inner groove 31, and the lower part of the main body 41 does not have a deformation allowing portion that allows positive deformation. Therefore, the lower part of the main body 41 can well support the pipe tower 4 as a heavy object.

[0033] The head 42 is a cylindrical body having a top portion that is closed in a dome shape. The head 42 is located above the outer tank 32. The head 42 is provided with a through hole for leading the pipes and wires passing through the pipe tower 4 to the outside, a manhole for operation, and the like.

[0034] The connection part 44 is cylindrical, and the interior of the connection part 44 communicates with the interiors of the main body 41 and the head 42. The connection part 44 of this embodiment is cylindrical with the vertical direction as the axial direction, but the connection part 44 may also be a square cylinder or an elliptical cylinder. Figure 3 1 is an enlarged vertical cross-sectional view of the upper portion of the liquefied gas tank 1 according to the embodiment. Figure 3 As shown, the connecting part 44 has a cylinder 441 and a lower annular plate 442. The cylinder 441 is a cylinder extending in the up-down direction, and the upper end of the cylinder 441 is connected to the lower end of the head 42. The cylinder 441 and the head 42 can also be continuous. In addition, the cylinder 441 and the head 42 can also be integrally formed.

[0035] The lower end of the cylinder 441 is joined to the outer edge of the lower annular plate 442. The lower annular plate 442 is an annular flat plate having a surface substantially perpendicular to the up-down direction. The lower annular plate 442 may also be an inclined truncated cone (for example, a truncated cone having an inner edge higher than an outer edge) having a direction that offsets elastic deformation. The shape of the outer edge of the lower annular plate 442 is substantially the same as the outer shape of the cylinder 441. An opening is formed substantially in the center of the lower annular plate 442, and the shape of the inner edge of the opening is substantially the same as the outer shape of the main body 41. The inner edge of the lower annular plate 442 is joined to the upper end of the main body 41. The lower annular plate 442 is flexible, and through the elastic deformation of the lower annular plate 442, the inner edge of the lower annular plate 442 can be displaced in the up-down direction relative to the outer edge of the lower annular plate 442. In this way, the lower annular plate 442 in the connecting portion 44 is the first deformation allowing portion A1 that actively allows deformation in the up-down direction.

[0036] The cylinder 441 of the connection part 44 has an inner groove joint part 48 for the top of the inner groove 31 to be joined and an outer groove joint part 49 for the top of the outer groove 32 to be joined. The inner groove 31 has a top opening for the cylinder 441 to be inserted through, and the inner edge of the top opening is airtightly joined to the cylinder 441. Similarly, the outer groove 32 has a top opening for the cylinder 441 to be inserted through, and the inner edge of the top opening is airtightly joined to the cylinder 441. The lower annular plate 442 of the connection part 44 and at least a portion of the cylinder 441 are located inside the inner groove 31.

[0037] In the tube tower 4 of the above structure, the outer diameter D2 of the head 42 is substantially the same as or larger than the outer diameter D1 of the main body 41. In addition, the outer diameter D4 of the connecting portion 44 (i.e., the outer diameter of the cylinder 441) is larger than the outer diameter D1 of the main body 41 and is the same as or larger than the outer diameter D2 of the head 42. In addition, "substantially the same" here includes the case where the two values ​​(outer diameters) are exactly the same, the difference between one of the two values ​​and the other value is less than about 10% of the one value, and the case where there is a difference between the two values ​​but the relationship between the two values ​​does not change significantly even if the two values ​​are considered to be the same.

[0038] exist Figure 3 In the illustrated liquefied gas tank 1, the outer diameter D4 of the connection portion 44 is larger than the outer diameter D1 of the main body 41, and the outer diameter D4 of the connection portion 44 is substantially the same as the outer diameter D2 of the head 42 (outer diameter D1 of the main body 41<outer diameter D4 of the connection portion 44≈outer diameter D2 of the head 42).

[0039] Here, use Figures 4 to 7 , a method for installing the tube tower 4 of the liquefied gas tank 1 according to the present embodiment will be described. Figure 4 4 is a diagram for explaining the structure of the assembly 40. Figure 5 and Figure 6 4 is a diagram for explaining the connection method of the connection portion 44. Figure 7It is a diagram for explaining the installation method of the tube tower 4.

[0040] like Figure 4 As shown, before the pipe tower 4 is installed in the inner tank 31 and the outer tank 32, an assembly 40 is produced in which the upper portion 411 of the main body 41, the head 42, the connecting portion 44, the top opening peripheral edge portion 311 of the inner tank 31 and the top opening peripheral edge portion 321 of the outer tank 32 are joined in an integrated manner. The assembly 40 may be produced in a factory instead of on-site.

[0041] like Figure 5 As shown, the coupling mode (assembly form) of the cylinder 441 of the connecting part 44 and the lower annular plate 442 may be that the upper surface of the lower annular plate 442 is coupled to the end surface of the cylinder 441. In addition, the coupling mode of the upper part 411 of the main body 41 and the lower annular plate 442 may be that the lower surface of the lower annular plate 442 is coupled to the end surface of the upper part 411 of the main body 41. Alternatively, as Figure 6 As shown, the barrel 441 of the connecting part 44 and the lower annular plate 442 may be joined by the circumferential surface of the lower annular plate 442 and the inner wall of the barrel 441. In addition, the upper portion 411 of the main body 41 and the lower annular plate 442 may be joined by the end surface of the lower annular plate 442 and the outer wall of the main body 41.

[0042] like Figure 7 As shown, when the pipe tower 4 is installed in the inner tank 31 and the outer tank 32, first, the lower portion 412 of the main body 41 of the pipe tower 4 is moved into the inner tank 31, and the lower end of the lower portion 412 of the main body 41 is rigidly joined to the bottom wall of the inner tank 31. Next, the assembly 40 is moved in, and the assembly 40 is arranged so that the upper portion 411 and the lower portion 412 of the main body 41 are aligned. Finally, the upper portion 411 and the lower portion 412 of the main body 41 are joined, the main body of the inner tank 31 is joined to the top opening peripheral portion 311, and the main body of the outer tank 32 is joined to the top opening peripheral portion 321.

[0043] In the above-mentioned method for setting the pipe tower 4, the assembly 40 includes the lower annular plate 442 as the first deformation allowing portion A1, and the load applied to the lower annular plate 442 in the state of the assembly 40 is derived from the weight of the connection portion 44, the main body 41, the top opening peripheral portion 311 of the inner groove 31, and the top opening peripheral portion 321 of the outer groove 32. Therefore, the degree of deformation (bending) of the lower annular plate 442 caused by the deadweight of the assembly 40 is sufficiently smaller than the degree of deformation of the plate material that is set at the lower part of the pipe tower 4 and supports the load of the entire pipe tower 4 as in the past. Therefore, when the cylinder 441 and the head 42 are connected to the lower annular plate 442, the process of supporting the lower annular plate 442 with a jack to ensure that the lower annular plate 442 does not bend can be omitted. According to such a method for setting the pipe tower 4, the number of joint work sites on site is reduced compared with the past, and the work is also simplified. Therefore, it can be expected that the construction performance of the pipe tower 4 will be improved and the time for setting work will be shortened.

[0044] Figure 8 1 is an enlarged vertical cross-sectional view of the upper portion of the liquefied gas tank 1 of the embodiment showing a state where the inner tank 31 and the tube tower 4 have undergone thermal contraction. Figure 8 As shown, when low-temperature liquefied gas is stored in the inner tank 31 of the liquefied gas tank 1, the inner tank 31 and the tube tower 4 shrink thermally. Temperature distribution occurs in the inner tank 31 and the tube tower 4, so even if they are made of the same material, the degree of thermal shrinkage is different. In the case where the shrinkage amount of the inner tank 31 and the tube tower 4 in the vertical direction is different, the lower annular plate 442 as the first deformation allowing portion A1 of the tube tower 4 elastically deforms in the vertical direction, thereby allowing the relative displacement of the inner tank 31 relative to the tube tower 4 in the vertical direction, avoiding the generation of high stress in the joint portion between the tube tower 4 and the inner tank 31. In addition, in the first deformation allowing portion A1, the lower annular plate 442 is actively deformed, but as the lower annular plate 442 is deformed, the cylinder 441 is also slightly deformed. In the above description, a case where a temperature difference between the inner tank 31 and the tube tower 4 is generated due to the heat or cold of the liquefied gas stored in the inner tank 31, thereby causing relative displacement between the inner tank 31 and the tube tower 4, is described. However, relative displacement may also occur when pressure or the weight of the liquid is applied to the inner tank 31 and the tube tower 4. In this case, the relative displacement can be absorbed by deformation of the first deformation allowing portion A1 in the same manner as described above.

[0045] Next, a modification of the above embodiment will be described. In the description of the modification, the same reference numerals as in the drawings are given to the same or similar components as those in the above embodiment, and the description thereof will be omitted.

[0046] [Variant 1]

[0047] Fig. 9 1 is a vertical cross-sectional view of a liquefied gas tank 1A according to a first modification of the embodiment. Fig. 9As shown, the liquefied gas tank 1A of the modification 1 is different from the liquefied gas tank 1 of the embodiment in that the outer diameter D4 of the connection portion 44 of the tube tower 4 is larger than the outer diameter D2 of the head portion 42 .

[0048] In the tube tower 4 of the liquefied gas tank 1A of the modification example 1, the outer diameter D1 of the main body 41 is substantially the same as the outer diameter D2 of the head 42, and the outer diameter D4 of the connecting portion 44 is larger than the outer diameter D1 of the main body 41 (the outer diameter D1 of the main body 41 ≈ the outer diameter D2 of the head 42 < the outer diameter D4 of the connecting portion 44). In this way, the outer diameter D4 of the connecting portion 44 is not restricted by the outer diameter D2 of the head 42, and can be larger than D2 of the head 42. The larger the outer diameter D4 of the connecting portion 44 is, the more greatly and easily the connecting portion 44 can be deformed in the up-down direction.

[0049] The connection part 44 of the pipe tower 4 of the liquefied gas tank 1A of the modification example 1 has a cylinder 441, a lower annular plate 442 and an upper annular plate 443. The upper annular plate 443 is an annular flat plate having a surface substantially perpendicular to the up-down direction. The shape of the outer edge of the upper annular plate 443 is substantially the same as the outer shape of the cylinder 441. An opening is formed in the approximate center of the upper annular plate 443, and the shape of the inner edge of the opening is substantially the same as the outer shape of the lower end of the head 42. The inner edge of the upper annular plate 443 is joined to the lower end of the head 42.

[0050] Although the inner groove 31 and the outer groove 32 are engaged with the cylinder 441 of the connecting portion 44, Fig.10 In the case where the outer groove 32 is joined to the upper end of the cylinder 441 , the upper annular plate 443 of the connecting portion 44 may be formed by a curved surface that smoothly continues with the outer groove 32 .

[0051] [Variant 2]

[0052] Fig.11 FIG. 2 is a vertical cross-sectional view of a liquefied gas tank 1B according to a second modification of the embodiment. Fig.11 As shown, the liquefied gas tank 1B of the second modification is different from the liquefied gas tank 1 of the embodiment in that the connection portion 44 of the tube tower 4 further has a deformation allowing portion (second deformation allowing portion A2) between the inner tank 31 and the outer tank 32 .

[0053] Fig.12 FIG. 2 is an enlarged vertical cross-sectional view of the upper portion of the liquefied gas tank 1B of Modification Example 2. Fig.12 As shown, in the liquefied gas tank 1B of the second modification, the cylinder 441 of the connection portion 44 of the tube tower 4 has at least one second deformation-allowing portion A2 between the inner groove joint portion 48 and the outer groove joint portion 49. The second deformation-allowing portion A2 includes an annular plate having a surface substantially perpendicular to the up-down direction. Instead of the annular plate, an inclined truncated cone having a direction that offsets the elastic deformation may be used. Fig.12In the illustrated liquefied gas tank 1B, the barrel 441 of the connection part 44 of the tube tower 4 has a groove 45 that is continuous in the circumferential direction between the inner groove joint 48 and the outer groove joint 49. The groove 45 is formed by a pair of annular plates (upper annular plate 451 and lower annular plate 452) and a short barrel 453 that are opposed in the up-down direction. The forming part of the groove 45 functions as a second deformation allowing portion A2. The outer diameter of the short barrel 453 inserted between the inner groove joint 48 and the outer groove joint 49 in the barrel 441 is smaller than the outer diameter of the barrel 441 (i.e., the outer diameter of the connection part 44). The outer edge of the upper annular plate 451 is engaged with the barrel 441, and the inner edge of the upper annular plate 451 is engaged with the upper end of the short barrel 453. The outer edge of the lower annular plate 452 is engaged with the barrel 441, and the inner edge of the lower annular plate 452 is engaged with the lower end of the lower annular plate 452.

[0054] The outer groove 32 has a rising portion 322 rising upward from the top opening. The rising portion 322 is joined to the connecting portion 44. The rising portion 322 may also be joined to the head portion 42 at the connecting portion between the connecting portion 44 and the head portion 42. In this way, a second deformation allowing portion A2 including an upper annular plate 451 and a lower annular plate 452 is provided between the connecting portion of the inner groove 31 and the connecting portion of the outer groove 32 in the connecting portion 44. In addition, the inside of the groove 45 becomes a space continuous with the grooves of the inner groove 31 and the outer groove 32, and this space can be used for piping and wiring.

[0055] In the liquefied gas tank 1B of the second modification, when the inner tank 31 contains low-temperature liquefied gas, the inner tank 31 and the tube tower 4 are thermally contracted. Fig.13As shown, the lower annular plate 442 of the connection portion 44 of the pipe tower 4 is elastically deformed in the vertical direction, allowing the inner tank 31 to be relatively displaced in the vertical direction relative to the pipe tower 4, thereby avoiding the generation of high stress in the joint portion between the pipe tower 4 and the inner tank 31. Moreover, the second deformation allowing portion A2 including the upper annular plate 451 and the lower annular plate 452 is elastically deformed in the vertical direction, allowing the pipe tower 4 to be relatively displaced in the vertical direction relative to the outer tank 32, and allowing the top of the inner tank 31 to be relatively displaced in the vertical direction relative to the top of the outer tank 32, thereby avoiding the generation of high stress in the joint portion between the pipe tower 4 and the inner tank 31 and the outer tank 32. In addition, in the second deformation allowing portion A2, the upper annular plate 451 and the lower annular plate 452 are actively deformed, but along with the deformation of the upper annular plate 451 and the lower annular plate 452, the short cylinder 453 and the cylinder 441 are also slightly deformed. In the above description, a case is described in which a temperature difference between the inner tank 31 and the tube tower 4 is generated due to the cold or hot of the liquefied gas stored in the inner tank 31, and a relative displacement is generated between the inner tank 31 and the tube tower 4, thereby generating a relative displacement between the outer tank 32 and the tube tower 4. However, relative displacement may also be generated by applying pressure or weight of the liquid to the inner tank 31 and the tube tower 4. In this case, the relative displacement can be absorbed by deformation of the first deformation allowing portion A1 and the second deformation allowing portion A2 as described above.

[0056] In addition, the liquefied gas tank 1B of the modification example 2 is a double-layer shell tank of the inner tank 31 and the outer tank 32, but in a multi-layer shell tank having three or more layers, the tube tower 4 can also be connected to the tank. Specifically, in the case of a multi-layer shell tank having at least one intermediate tank between the inner tank 31 and the outer tank 32, a deformation allowing portion is provided in the tube tower 4 between the joint of the inner tank 31 and the joint of the intermediate tank immediately outside the inner tank 31, and a deformation allowing portion is provided in the tube tower 4 between the joint of the intermediate tank and the joint of the outer tank 32 and / or between the joints of the intermediate layers.

[0057] 〔Summarize〕

[0058] The liquefied gas tank 1, 1A, 1B of the first item of the present disclosure has: an inner tank 31, which stores liquefied gas; an outer tank 32, which surrounds the inner tank 31; and a cylindrical tube tower 4, the tube tower 4 has: a main body 41, which has a lower end connected to the bottom wall in the inner tank 31; a head 42, which is located above the outer tank 32; and a connecting part 44, which connects the main body 41 and the head 42 in the up-down direction, and the tube tower 4 penetrates the inner tank 31 and the outer tank 32 from the bottom wall of the inner tank 31 and extends in the up-down direction.

[0059] Furthermore, the connection portion 44 of the pipe tower 4 includes: a cylinder 441, which extends in the up-down direction and has an inner groove joint portion 48 for joining the top of the inner groove 31 and an outer groove joint portion 49 for joining the top of the outer groove 32; and a first deformation allowing portion A1, which connects the cylinder 441 to the upper end of the main body 41 and allows the upper end of the main body 41 to be displaced in the up-down direction relative to the cylinder 441 through elastic deformation.

[0060] Regarding the liquefied gas tank 1, 1A, 1B of the second item of the present disclosure, in the liquefied gas tank 1, 1A, 1B of the first item, the first deformation allowing portion A1 is an annular plate (lower annular plate 442) having an outer edge joined to the lower end of the cylinder 441 and an inner edge joined to the upper end of the main body 41.

[0061] In the liquefied gas tanks 1, liquefied gas tanks 1A, and liquefied gas tanks 1B of the first and second items, relative displacement of the tube tower 4 in the vertical direction relative to the inner tank 31 may occur. Such relative displacement may occur, for example, due to thermal contraction of the inner tank 31 and the tube tower 4 when low-temperature liquefied gas is stored in the inner tank 31 of the liquefied gas tank 1. Here, the first deformation allowing portion A1 (i.e., the lower annular plate 442) of the tube tower 4 is elastically deformed to allow relative displacement of the tube tower 4 in the vertical direction relative to the inner tank 31, thereby avoiding generation of high stress at the junction of the inner tank 31 and the tube tower 4.

[0062] In addition, the first deformation-allowing portion A1 of the tube tower 4 (i.e., the lower annular plate 442) does not support the deadweight of the main body 41, so the degree of deformation of the first deformation-allowing portion A1 caused by the deadweight of the tube tower 4 is sufficiently smaller than the degree of deformation of the plate material that is conventionally provided at the lower portion of the tube tower 4 and supports the overall load of the tube tower 4. Therefore, in the installation process of the tube tower 4, the treatment of supporting the first deformation-allowing portion A1 in a manner that ensures that it does not deform can be omitted. In this way, according to the present disclosure, it is possible to provide a liquefied gas tank 1, 1A, 1B having a multilayer shell structure that includes a tube tower 4 and realizes a simplified installation process of the tube tower 4.

[0063] Regarding the liquefied gas tank 1 , 1A, 1B of the third aspect of the present disclosure, in the liquefied gas tank 1 , 1A, 1B of the second aspect, the upper surface of the annular plate 442 is joined to the end surface of the cylinder 441 , and the lower surface of the annular plate 442 is joined to the end surface of the main body 41 .

[0064] According to the liquefied gas tank 1, 1A, 1B, welding deformation can be reduced and excessive stress can be prevented by selecting an appropriate combination method of the annular plate 442 and the main body 41. Moreover, since welding deformation can be reduced, a jig or the like for preventing welding deformation is not required.

[0065] Regarding the liquefied gas tank 1 , 1A, 1B of the fourth aspect of the present disclosure, in the liquefied gas tank 1 , 1A, 1B of the second aspect, the circumferential surface of the annular plate 442 is joined to the inner wall of the cylinder 441 , and the end surface of the annular plate 442 is joined to the outer wall of the main body 41 .

[0066] According to the liquefied gas tank 1, 1A, 1B, welding deformation can be reduced and excessive stress can be prevented by selecting an appropriate combination method of the annular plate 442 and the main body 41. Moreover, since welding deformation can be reduced, a clamp or the like for preventing welding deformation is not required.

[0067] Regarding the liquefied gas tank 1, 1A, 1B of the fifth item of the present disclosure, in the liquefied gas tank 1 of any of the first to fourth items, the outer diameter D4 of the connecting portion 44 is larger than the outer diameter D1 of the main body 41, and the outer diameter D4 of the connecting portion 44 is substantially the same as or larger than the outer diameter D2 of the head 42.

[0068] Thus, the outer diameter D4 of the connection portion 44 is an arbitrary value not restricted by the head portion 42. Therefore, the difference between the outer diameter D4 of the connection portion 44 and the outer diameter D1 of the body portion 41 can be designed according to the difference in deformation amounts of the inner tank 31 and the tube tower 4 to be absorbed.

[0069] Regarding the liquefied gas tank 1B of the sixth item of the present disclosure, in the liquefied gas tank 1, 1A, 1B of any of the first to fifth items, the connecting portion 44 of the tube tower 4 has a second deformation allowing portion A2 between the inner groove joint 48 and the outer groove joint 49, and the second deformation allowing portion A2 allows the inner groove joint 48 to be displaced in the up and down directions relative to the outer groove joint 49 through elastic deformation.

[0070] Regarding the liquefied gas tank 1B of the seventh item of the present disclosure, in the liquefied gas tank 1B of the sixth item, the second deformation allowing portion A2 has: a short cylinder 453, which is inserted between the inner groove joint 48 and the outer groove joint 49 of the cylinder 441 and has a diameter smaller than the diameter of the cylinder 441; and a pair of annular plates 451, 452, which are opposite to each other in the up and down directions and have an outer edge joined to the cylinder 441 and an inner edge joined to the short cylinder 453.

[0071] In the liquefied gas tank 1B of the sixth and seventh items, the second deformation allowing portion A2 is used to allow relative displacement of the tube tower 4 in the up-down direction relative to the top of the outer tank 32 joined to the outer tank joint portion 49, and relative displacement of the top of the inner tank 31 in the up-down direction relative to the top of the outer tank 32 is allowed, thereby avoiding the generation of high stress in the joint portions between the tube tower 4 and the inner tank 31 and the outer tank 32.

[0072] Regarding the liquefied gas tank 1B of the eighth item of the present disclosure, in the liquefied gas tank 1B of the seventh item, a groove 45 continuous along the circumferential direction is formed on the cylinder 441 by a short cylinder 453 and a pair of annular plates 451, 452, and the interior of the groove 45 is connected to the grooves between the inner groove 31 and the outer groove 32.

[0073] Thus, the pipes and wires passing through the grooves between the inner tank 31 and the outer tank 32 can be led out to the vicinity of the head 42 of the tube tower 4 by using the concave groove 45 .

[0074] Regarding the liquefied gas tank 1, 1A, 1B of the ninth aspect of the present disclosure, in the liquefied gas tank 1, 1A, 1B of any of the first to eighth aspects, the lower end of the main body 41 of the tube tower 4 is joined to the inner tank without a member allowing deformation.

[0075] By increasing the rigidity of the lower portion of the main body 41 of the pipe tower 4 in this manner, the entire pipe tower 4 , which is a heavy object, can be well supported at the lower portion of the main body 41 .

[0076] The above discussion of the present disclosure is presented for the purpose of illustration and description, and is not intended to limit the present disclosure to the methods disclosed in this specification. For example, in the aforementioned detailed description, the various features of the present disclosure are summarized into one embodiment and its variations for the purpose of rationalizing the present disclosure, but several of the multiple features may also be combined. In addition, the multiple features included in the present disclosure may also be combined with alternative embodiments, structures or methods other than those described above.

Claims

1. A liquefied gas tank, comprising: an inner tank for storing liquefied gas; an outer tank surrounding the inner tank; and A cylindrical pipe tower, comprising a main body, a head and a connecting part, wherein the main body has a lower end connected to the bottom wall in the inner tank, the head is located above the outer tank, the connecting part penetrates the inner tank and the outer tank and connects the main body and the head in the vertical direction, and the pipe tower extends from the bottom wall of the inner tank in the vertical direction. The connecting portion of the pipe tower has a cylinder and a first deformation allowing portion, the cylinder extending in the up-down direction and having an inner groove engaging portion for engaging the top of the inner groove and an outer groove engaging portion for engaging the top of the outer groove, the first deformation allowing portion connecting the cylinder with the upper end of the main body, and the first deformation allowing portion allowing displacement of the main body relative to the cylinder through elastic deformation.

2. The liquefied gas tank according to claim 1, wherein: The first deformation allowing portion is an annular plate having an outer edge engaged with a lower end of the cylindrical body and an inner edge engaged with an upper end of the main body portion.

3. The liquefied gas tank according to claim 2, wherein: The upper surface of the annular plate is joined to the end surface of the cylinder, and the lower surface of the annular plate is joined to the end surface of the main body.

4. The liquefied gas tank according to claim 2, wherein: The peripheral surface of the annular plate is joined to the inner wall of the cylinder, and the end surface of the annular plate is joined to the outer wall of the main body.

5. The liquefied gas tank according to any one of claims 1 to 4, wherein: The outer diameter of the connection portion is larger than the outer diameter of the main body portion, and the outer diameter of the connection portion is substantially the same as or larger than the outer diameter of the head portion.

6. The liquefied gas tank according to any one of claims 1 to 5, wherein: The connection portion of the pipe tower has a second deformation allowing portion between the inner groove joint portion and the outer groove joint portion, and the second deformation allowing portion allows displacement of the inner groove joint portion relative to the outer groove joint portion in the up-down direction by elastic deformation.

7. The liquefied gas tank according to claim 6, wherein: The second deformation allowing portion has: a short cylinder which is inserted between the inner groove joint portion and the outer groove joint portion of the cylinder and has a diameter smaller than that of the cylinder; and A pair of annular plates are opposed to each other in the up-down direction and have outer edges engaged with the cylinder and inner edges engaged with the short cylinder.

8. The liquefied gas tank according to claim 7, wherein: A groove continuous in the circumferential direction is formed on the cylinder by the short cylinder and the pair of annular plates, and the interior of the groove is communicated with the inner groove and the outer groove.

9. The liquefied gas tank according to any one of claims 1 to 8, wherein: The lower end of the main body of the tube tower is engaged with the inner tank without a member allowing deformation.

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