Multi-layer shell tank

Abstract

The multi-layer shell can has: an inner tank; an outer tank surrounding the inner tank; and a partition wall joined to one of the inner groove and the outer groove, the partition wall being disposed between the inner groove and the outer groove and partitioning the groove space into a first space and a second space. The partition wall has a ventilation part that allows the first space and the second space to communicate with each other so as to allow ventilation. The ventilation part has a first opening that is disposed in a boundary region along the boundary between the partition wall and the groove and that opens into the first space, and a second opening that is disposed in the boundary region and that opens into the second space.

Description

Technical Field

[0001] The present disclosure relates to a multi-layer shell tank having at least two inner and outer grooves. Background Art

[0002] In the past, a multilayer shell tank having an inner tank and an outer tank surrounding the inner tank is known. The multilayer shell tank is used, for example, for storing low-temperature liquefied gas. In such a multilayer shell tank, a structure in which the inner tank is supported by a cylindrical member called a skirt is known. For example, Patent Document 1 discloses such a multilayer shell tank. In the double-layer shell tank of Patent Document 1, an inspection hole for operation is provided in a portion of the skirt that is approximately in the upper and lower center between the inner tank and the outer tank.

[0003] In a multilayer shell tank, a gas other than air is sometimes filled between the inner tank and the outer tank (i.e., between the inner and outer tanks). When replacing the gas between the inner and outer tanks, the existing gas between the inner and outer tanks is gas-purged in a piston flow manner that utilizes the specific gravity difference of the gas. In such gas purging, for example, a purge gas having a lower density than the existing gas between the inner and outer tanks is supplied from the upper portion of the inner tank, and the existing gas is discharged from the lower portion of the inner and outer tanks. Alternatively, a purge gas having a higher density than the existing gas between the inner and outer tanks is supplied from the lower portion of the inner and outer tanks, and the existing gas is discharged from the upper portion of the inner and outer tanks.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 11-82896 Summary of the invention

[0007] Problems to be solved by the invention

[0008] When gas purging is performed on the existing gas between the inner and outer tanks, in the double-shell tank of Patent Document 1, the gas can pass through the skirt between the inner and outer tanks through the inspection hole formed in the skirt. However, if there is a narrow recess between the inner and outer tanks, the existing gas contained in the recess cannot be squeezed out by the purging gas, so the existing gas is retained in the recess. The narrow recess between the inner and outer tanks is, for example, the junction (or intersection) of the inner tank or the outer tank and the skirt.

[0009] The present disclosure is completed in view of the above situation, and its purpose is to propose the following structure: in a multi-layer shell tank having an inner groove and an outer groove, and a partition wall (for example, a supporting skirt) that is joined to the inner groove and the outer groove to separate the grooves of the inner groove and the outer groove, the retention of gas near the joint between the partition wall and the outer groove or the inner groove is suppressed.

[0010] Means for solving problems

[0011] In order to solve the above-mentioned problems, a multilayer shell tank of one embodiment of the present invention comprises: an inner groove; an outer groove, which surrounds the inner groove; and a partition wall, which is connected to one of the inner groove and the outer groove, and the partition wall is arranged between the grooves of the inner groove and the outer groove to divide the grooves into a first space and a second space, the partition wall has a ventilation portion that connects the first space and the second space in a ventilated manner, and the ventilation portion has a first opening arranged in a boundary area along the boundary of the partition wall and the groove and opening in the first space, and a second opening arranged in the boundary area and opening in the second space.

[0012] Effects of the Invention

[0013] According to the present disclosure, a structure can be provided in which, in a multilayer shell tank having an inner groove and an outer groove and a partition wall joined to the inner groove and the outer groove to partition the inner groove and the outer groove, gas accumulation near a joint between the partition wall and the outer groove or the inner groove is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing a schematic structure of a multilayer shell tank according to a first embodiment of the present disclosure.

[0015] Figure 2 yes Figure 1 A partial enlarged cross-sectional view of a multi-layer shell tank.

[0016] Figure 3 It is a partial expanded view of the partition wall of the multi-layer shell tank.

[0017] Figure 4 This is a partial development view of the partition wall for explaining the arrangement of the ventilation portion and the communication hole.

[0018] Figure 5 It is a cross-sectional view showing a schematic structure of a multi-layer shell tank having pipes.

[0019] Figure 6 This is a cross-sectional view of a multilayer shell tank for explaining how purge gas is supplied from the top between the inner and outer tanks to discharge the existing gas between the inner and outer tanks.

[0020] Figure 7 This is a cross-sectional view of a multi-layer shell tank for explaining how purge gas is supplied from the bottom between the inner and outer tanks to discharge the existing gas between the inner and outer tanks.

[0021] Figure 8 This is a partial development view of a partition wall of a multilayer shell tank according to Modification 1 of the first embodiment.

[0022] Fig. 9 It is a partial development view of a partition wall of a multilayer shell tank according to Modification 2 of the first embodiment.

[0023] Fig.10 It is a partially enlarged cross-sectional view of a multilayer shell tank according to Modification 3 of the first embodiment.

[0024] Fig.11 It is a cross-sectional view showing a schematic structure of a multilayer shell tank according to a second embodiment of the present disclosure.

[0025] Fig.12 yes Fig.11 A partial enlarged cross-sectional view of a multi-layer shell tank.

[0026] Fig.13 It is a partially enlarged cross-sectional view of a multilayer shell tank according to Modification 1 of the second embodiment.

[0027] Fig.14 It is a cross-sectional view showing a schematic structure of a multilayer shell tank according to a third embodiment.

[0028] Fig.15 It is a partially enlarged cross-sectional view of the multilayer shell tank according to the third embodiment.

[0029] Fig.16 It is a partially enlarged cross-sectional view of the multilayer shell tank according to the third embodiment. DETAILED DESCRIPTION

[0030] [First embodiment]

[0031] Next, a first embodiment of the present disclosure will be described with reference to the drawings. Figure 1 It is a cross-sectional view showing a schematic structure of a multilayer shell tank 1 according to a first embodiment of the present disclosure. Figure 1 The multilayer shell tank 1 shown is, for example, a container for storing low-temperature liquefied gases such as LNG or liquefied hydrogen. The multilayer shell tank 1 has an inner tank 11 and an outer tank 12 surrounding the inner tank 11. The inner tank 11 is separated from the outer tank 12, and the space between the inner tank 11 and the outer tank 12 (i.e., the space 13 between the inner and outer tanks) becomes a cold insulation layer. The shape of the inner tank 11 is not limited, and may be, for example, spherical, spherical, square, or capsule-shaped with a hemispherical upper and lower parts and a cylindrical main body. In addition, the shape of the outer tank 12 is not limited, and may be a shape similar to that of the inner tank 11 or a shape different from that of the inner tank 11.

[0032] The inner tank 11 is supported on the seat 3 via the skirt 2. The skirt 2 is cylindrical with an axis extending in the vertical direction as the center. In addition, the vertical direction is not strictly limited to the vertical direction, and may be inclined from the vertical direction. In the case where the multilayer shell tank 1 is mounted on a ship, the seat 3 may be a hull. In addition, in the case where the multilayer shell tank 1 is installed on the ground, the seat 3 may be a concrete foundation.

[0033] The skirt 2 of this embodiment is erected on the seat 3 and joined to the inner groove 11 and the outer groove 12. However, the skirt 2 may be disposed between the inner and outer grooves 13, the inner groove 11 being supported on the outer groove 12 via the skirt 2, and the outer groove 12 being supported on the seat 3 via a block or other skirt support members.

[0034] Figure 2 is a partial enlarged cross-sectional view of the multi-layer shell tank 1, Figure 3 FIG. 2 is a partial expanded view of the partition wall 20 of the multilayer shell tank 1. Figures 1 to 3 As shown, the skirt 2 is composed of a first skirt member 2a disposed between the inner and outer grooves 13, a second skirt member 2b disposed outside the outer groove 12, and a connecting member 2c connecting the first skirt member 2a and the second skirt member 2b in the vertical direction. An annular connecting member 111 is disposed in the upper and lower midway of the inner groove 11, and the upper end of the first skirt member 2a is joined to the connecting member 111. The outer groove 12 is joined to the connecting member 2c, and the skirt 2 and the outer groove 12 intersect at the connecting member 2c. The connecting member 2c serves as both a constituent element of the skirt 2 and a constituent element of the outer groove 12. In such a skirt 2, the first skirt member 2a of the skirt 2 is a supporting member for supporting the inner groove 11, and is also a partition wall 20 that partitions the inner and outer grooves 13. The partition wall 20 partitions the inner and outer grooves 13 into a first space 16 and a second space 17.

[0035] In the above structure, the boundary B1 between the outer groove 12 and the partition wall 20 is defined as the junction between the connecting member 2c, which is one of the components of the outer groove 12, and the partition wall 20. However, the skirt 2 may be provided as a cylindrical member continuous in the up-down direction, and the intersection of the outer groove 12 and the skirt 2 may be defined as the boundary B1 between the outer groove 12 and the partition wall 20. In the above structure, the boundary B2 between the inner groove 11 and the partition wall 20 is defined as the junction between the connecting member 111, which is one of the components of the inner groove 11, and the partition wall 20. The boundary B2 between the inner groove 11 and the partition wall 20 is continuous in the circumferential direction along the outer surface of the inner groove 11.

[0036] In the space between the inner and outer grooves 13, a narrow portion 28 sandwiched between the partition wall 20 and the outer groove 12 is formed near the boundary B1 between the partition wall 20 and the outer groove 12. In order to promote the circulation of gas in the narrow portion 28, at least one vent 25 is provided in the boundary area A1 of the partition wall 20. Preferably, a plurality of vents 25 are dispersedly provided in the circumferential direction in the boundary area A1 of the partition wall 20. Here, the "boundary area A1" is an area that is continuous in the circumferential direction along the boundary B1 between the partition wall 20 and the outer groove 12, and is an area near the boundary B1 between the partition wall 20 and the outer groove 12. The boundary area A1 may also include the boundary B1. Hereinafter, the vent 25 arranged in the boundary area A1 of the partition wall 20 is sometimes referred to as a lower vent 25b.

[0037] The vent 25 has a first opening 18 opened to the first space 16 and a second opening 19 opened to the second space 17. In other words, the first opening 18 opens in the first space 16, and the second opening 19 opens in the second space 17. The vent 25 has a passage connecting the first opening 18 and the second opening 19, and the first space 16 and the second space 17 are connected through the vent 25. The first opening 18 is arranged in the boundary area A1 of the partition wall 20 in the first space 16. The second opening 19 is arranged in the boundary area A1 of the partition wall 20 in the second space 17. That is, the second opening 19 is arranged in the narrow portion 28.

[0038] For the purpose of promoting the flow of gas in the narrow portion 28, the boundary area A1 of the partition wall 20 may be a range of 1 / 6 of the height of the partition wall 20 from the boundary B1 between the partition wall 20 and the outer tank 12 to the upper side. Alternatively, the boundary area A1 of the partition wall 20 may be a range of 1 / 10 of the height of the partition wall 20 from the boundary B1 between the partition wall 20 and the outer tank 12 to the upper side. Alternatively, the boundary area A1 of the partition wall 20 may be a range of 500 mm from the lower edge B1 of the partition wall 20 to the upper side.

[0039] In the present embodiment, the vent 25 is a vent hole 250 that penetrates the partition wall 20 in the thickness direction thereof. The shape and size of the vent 250 as the vent 25 are not particularly limited, and may be a circular, rectangular or polygonal hole with a diameter of about tens to hundreds of millimeters. The vent 250 of such a size has a sufficient opening area for the purpose of ventilation. As the vent 250 as the vent 25, as long as its lowermost portion 25a (i.e., the lowest point forming the opening edge of the vent 250) is located in the boundary area A1 of the partition wall 20. Preferably, the first opening 18 and the second opening 19 avoid the weld between the partition wall 20 and the outer groove 12 and are arranged along the boundary B1 between the partition wall 20 and the outer groove 12. In this case, the lowermost portion 25a of the vent 250 avoids the weld of the boundary B1 between the partition wall 20 and the outer groove 12 and is located directly above the weld, and is located at the actual lowermost portion in the partition wall 20. This can effectively suppress the accumulation of gas in the narrow portion 28 .

[0040] A communication hole 26 may also be provided on the partition wall 20. The communication hole 26 is a hole that penetrates the partition wall 20 from inside to outside, and is a hole or opening that allows an operator to access from the inside to the outside of the partition wall 20 or from the outside to the inside of the partition wall 20. Figure 3As shown, it is preferred that the traffic hole 26 is provided in the partition wall 20 at a position above the vent hole 250 and outside the boundary area A1. The traffic hole 26 is a hole for people to pass through, and requires a larger opening area than the vent hole 250. Therefore, the strength of the portion of the partition wall 20 where the traffic hole 26 is provided may be reduced compared to other portions. Therefore, it is preferred that, in the partition wall 20, the traffic hole 26 is arranged at a position above the vent hole 250 and close to the center of the partition wall 20 in the vertical direction. A step 41 for accessing the traffic hole 26 may also be provided on the partition wall 20. Moreover, as shown in FIG. Figure 4 As shown, preferably, in the partition wall 20, the vent hole 250 and the communication hole 26 are separately arranged in the lateral direction (i.e., the continuous direction of the boundary B1 between the partition wall 20 and the outer groove 12), in other words, the vent hole 250 and the communication hole 26 are arranged in a non-repetitive lateral position.

[0041] In addition, the vent hole 250 as the vent portion 25 may also function as a passage for piping and / or wiring. In other words, the multilayer shell tank 1 may have piping or wiring passing through the vent hole 250. In this case, for example, Figure 5 As shown, the pipe 14 is laid in a manner extending to the inside (or outside) of the partition wall 20 through the inner and outer grooves 13 and through the vent hole 250 provided in the partition wall 20. In addition, in this case, the size of the vent hole 250 can be appropriately increased according to the size of the pipe / wiring.

[0042] [Method for replacing gas between inner and outer tanks 13]

[0043] A method of replacing the gas between the inner and outer tanks 13 in the multilayer shell tank 1 having the above-mentioned structure will be described. Figure 6 1 is a cross-sectional view of the multilayer shell tank 1 for explaining the situation in which the purge gas 31 is supplied from the top of the inner and outer tanks 13 to discharge the existing gas 32 in the inner and outer tanks 13. Figure 6 As shown, in the multilayer shell tank 1 of the above structure, when the purge gas 31 having a smaller specific gravity than the existing gas 32 is supplied from the top of the inner and outer tanks 13 and the existing gas 32 in the inner and outer tanks 13 is discharged from the bottom of the inner and outer tanks 13, the existing gas 32 in the inner and outer tanks 13 is squeezed outward by the piston flow formed by the purge gas 31. At this time, the existing gas 32 in the narrow portion 28 generated at the junction of the partition wall 20 and the outer tank 12 passes through the vent hole 250 and moves from the outside of the partition wall 20 to the inside, so that the existing gas 32 in the narrow portion 28 will not be retained. In addition, Figure 7 1 is a cross-sectional view of the multilayer shell tank 1 for explaining the situation in which the purge gas 31 is supplied from the bottom of the inner and outer tanks 13 to discharge the existing gas 32 in the inner and outer tanks 13. Figure 7As shown, in the multilayer shell tank 1 of the above structure, when the purge gas 31 having a specific gravity greater than that of the existing gas 32 is supplied from the bottom of the inner and outer tanks 13 and the existing gas 32 in the inner and outer tanks 13 is discharged from the top of the inner and outer tanks 13, the existing gas 32 in the inner and outer tanks 13 is squeezed outward by the piston flow formed by the purge gas 31. At this time, the existing gas 32 in the narrow portion 28 generated at the junction of the partition wall 20 and the outer tank 12 is squeezed out by the flow of the purge gas 31 that moves from the inside to the outside of the partition wall 20 through the vent hole 250, so that the existing gas 32 in the narrow portion 28 does not accumulate.

[0044] [Variant 1]

[0045] In the multilayer shell tank 1 of the first embodiment, the vent hole 250 as the vent portion 25 is independent of the communication hole 26, but the vent hole 250 and the communication hole 26 may be continuous. That is, the vent hole 250 and the communication hole 26 may not be independent openings, but one opening may function as the vent hole 250 and the communication hole 26. Figure 8 FIG. 2 is a partial development view of the partition wall 20 of the multilayer shell tank 1 according to the first modification of the first embodiment. Figure 8 In the multilayer shell tank 1 shown, the partition wall 20 has a communication hole 26 that is continuous with the vent hole 250. The vent hole 250 is formed by causing a portion of the opening edge of the communication hole 26 to protrude downward to the boundary area A1 of the partition wall 20.

[0046] [Variant 2]

[0047] Fig. 9 FIG. 2 is a partial development view of the partition wall 20 of the multilayer shell tank 1 according to the second modification of the first embodiment. Fig. 9 In the multilayer shell tank 1 shown, as in the aforementioned modification 1, one opening functions as a vent hole 250 and a communication hole 26. The communication hole 26 provided in the partition wall 20 has a lowermost portion located in the boundary area A1 of the partition wall 20, and the communication hole 26 functions as a ventilating portion 25 during ventilation between the inner and outer tanks 13.

[0048] [Variant 3]

[0049] In the multilayer shell tank 1 of the first embodiment described above, the vent 25 is the lower vent 25b arranged in the boundary area A1 along the boundary B1 between the partition wall 20 and the outer groove 12, but the vent 25 may be arranged in the boundary area A2 along the boundary B2 between the partition wall 20 and the inner groove 11. In addition, the partition wall 20 of the multilayer shell tank 1 may also have the vent 25 in both the boundary area A1 and the boundary area A2. Here, the "boundary area A2" is an area continuous in the circumferential direction along the boundary B2 between the partition wall 20 and the inner groove 11, and is an area near the boundary B2 between the partition wall 20 and the inner groove 11. The boundary area A2 may also include the boundary B2 of the inner groove 11.

[0050] Fig.10 FIG. 1 is a partially enlarged cross-sectional view of a multilayer shell tank 1 according to a third variation of the first embodiment. Fig.10 As shown, a narrow portion 28 sandwiched between the inner wall of the partition wall 20 and the outer wall of the inner tank 11 is formed near the boundary B2 between the partition wall 20 and the inner tank 11. In order to promote the flow of gas in the narrow portion 28, at least one vent 25 is provided in the boundary area A2 of the partition wall 20. The vent 25 arranged in the boundary area A2 of the partition wall 20 is sometimes referred to as an upper vent 25u.

[0051] In addition, from the purpose of promoting the gas flow in the narrow part 28, the boundary area A2 of the partition wall 20 may be a range of 1 / 6 of the height of the partition wall 20 from the boundary B2 between the partition wall 20 and the inner groove 11 to the bottom. Alternatively, the boundary area A2 of the partition wall 20 may be a range of 1 / 10 of the height of the partition wall 20 from the boundary B2 between the partition wall 20 and the inner groove 11 to the bottom. Alternatively, the boundary area A2 of the partition wall 20 may be a range of 500 mm from the boundary B2 between the partition wall 20 and the inner groove 11 to the bottom. Preferably, the first opening 18 and the second opening 19 are arranged along the boundary B2 between the partition wall 20 and the inner groove 11 to avoid the weld. In this case, the first opening 18 and the second opening 19 may be arranged directly below the weld to avoid the weld of the partition wall 20.

[0052] exist Fig.10 In the example shown, the upper ventilation portion 25u is a ventilation hole 250 that penetrates the boundary area A2 of the partition wall 20 in the thickness direction thereof. The ventilation hole 250 has a first opening 18 that opens in the first space 16, a second opening 19 that opens in the second space 17, and a passage that connects the first opening 18 and the second opening 19. However, the upper ventilation portion 25u may also be a ventilation hole 250 in the manner shown in the above-mentioned Modification 1 or Modification 2.

[0053] In the multilayer shell tank 1 of the third modification of the above structure, when the purge gas 31 having a greater specific gravity than the existing gas 32 is supplied from the bottom of the inner and outer tanks 13 to discharge the existing gas 32 in the inner and outer tanks 13, the existing gas 32 in the narrow portion 28 passes through the upper vent 25u and flows from the first space 16 to the second space 17. In this way, the existing gas 32 in the narrow portion 28 can be prevented from being retained.

[0054] [Second embodiment]

[0055] Next, a second embodiment will be described. Fig.11 is a cross-sectional view showing a schematic structure of a multilayer shell tank 1A according to a second embodiment of the present disclosure. Fig.12 yes Fig.11 In the description of this embodiment, the same reference numerals are used for the same or similar components as those in the above-mentioned embodiment, and the description thereof will be omitted.

[0056] like Fig.11 and Fig.12 As shown, in order to promote the flow of gas in the narrow portion 28 between the inner and outer grooves 13, at least one vent 25 (lower vent 25b) is provided in the boundary area A1 of the partition wall 20. In addition, a traffic hole 26 is provided in the center of the partition wall 20 in the vertical direction so that people can pass through.

[0057] The ventilation portion 25 of the present embodiment is constituted by a ventilation pipe 251 having a first opening 18 opened in the first space 16, a second opening 19 opened in the second space 17, and a passage connecting the first opening 18 and the second opening 19. The first opening 18 is arranged at one end of the ventilation pipe 251, and the second opening 19 is arranged at the other end of the ventilation pipe 251. The first opening 18 is arranged at or near the lower end of the partition wall 20 in the first space 16. The second opening 19 is arranged at or near the lower end of the partition wall 20 in the second space 17. That is, the second opening 19 is arranged at the narrow portion 28. The ventilation pipe 251 extends upward from the lower end of the partition wall 20 in the first space 16, passes through the communication hole 26, bends in the communication hole 26, and extends downward to reach the lower end of the partition wall 20 in the second space 17. The ventilation pipe 251 can be composed of a curved pipe such as a U-shaped pipe, for example.

[0058] In the ventilation part 25 of this embodiment, the ventilation pipe 251 passes through the communication hole 26, so there is no need to provide a dedicated opening for the ventilation part 25 in the partition wall 20. However, the partition wall 20 may have a hole for the ventilation pipe 251 to pass through at a position above the lower end.

[0059] In the multilayer shell tank 1A of the above structure, when the purge gas 31 having a smaller specific gravity than the existing gas 32 is supplied from the top of the inner and outer tanks 13, a pressure difference is generated between the first opening 18 and the second opening 19 of the vent pipe 251, and the gas flows in the vent pipe 251, and the existing gas 32 is discharged from the narrow portion 28. In this way, a forced gas flow is also generated in the narrow portion 28, and the existing gas 32 in the narrow portion 28 can be prevented from being retained.

[0060] [Variant 1]

[0061] In the multilayer shell tank 1A of the second embodiment, the vent 25 is the lower vent 25b disposed in the boundary region A1 of the partition wall 20, but the vent 25 may be disposed in the boundary region A2 of the partition wall 20. In addition, the partition wall 20 of the multilayer shell tank 1A may have the vent 25 in both the boundary region A1 and the boundary region A2.

[0062] Fig.13 FIG. 2 is a partially enlarged cross-sectional view of a multilayer shell tank 1A according to a first modification of the second embodiment. Fig.13 As shown, a narrow portion 28 sandwiched between the partition wall 20 and the inner groove 11 is formed near the boundary B2 between the partition wall 20 and the inner groove 11. In order to promote the flow of gas in the narrow portion 28, at least one vent 25 (upper vent 25u) is provided in the boundary area A2 of the partition wall 20.

[0063] exist Fig.13 In the example shown, the upper ventilation portion 25u is composed of a ventilation pipe 251 having a first opening 18 opened in the first space 16, a second opening 19 opened in the second space 17, and a passage connecting the first opening 18 and the second opening 19. The first opening 18 is arranged at one end of the ventilation pipe 251, and the second opening 19 is arranged at the other end of the ventilation pipe 251. The first opening 18 is arranged at or near the upper end of the partition wall 20 in the first space 16. The second opening 19 is arranged at or near the upper end of the partition wall 20 in the second space 17. That is, the first opening 18 is arranged at the narrow portion 28. The ventilation pipe 251 extends downward from the upper end of the partition wall 20 in the first space 16, passes through the communication hole 26, bends in the communication hole 26, and extends upward to reach the upper end of the partition wall 20 in the second space 17. The ventilation pipe 251 can be composed of a curved pipe such as a U-shaped pipe, for example.

[0064] In the multilayer shell tank 1A of the modification 1 of the above structure, when the purge gas 31 having a specific gravity greater than that of the existing gas 32 is supplied from the bottom of the inner and outer tanks 13 to discharge the existing gas 32 in the inner and outer tanks 13, a pressure difference is generated between the first opening 18 and the second opening 19 of the vent pipe 251, and the gas flows in the vent pipe 251. In this way, the existing gas 32 flows from the narrow portion 28 to the second space 17, and the existing gas 32 in the narrow portion 28 can be prevented from being retained.

[0065] [Third embodiment]

[0066] Next, a third embodiment will be described. Fig.14 It is a cross-sectional view showing a schematic structure of a multilayer shell tank 1B according to a third embodiment of the present disclosure. In the description of this embodiment, the same reference numerals are given to the same or similar components as those in the above embodiment, and the description thereof will be omitted.

[0067] exist Fig.14 In the multilayer shell tank 1B shown, a rib 36 is provided on the outer wall of the inner groove 11 in the inner and outer grooves 13. The rib 36 not only functions as a reinforcing member of the inner groove 11, but also functions as a supporting member of the heat insulating member arranged on the outer wall of the inner groove 11. The rib 36 is joined to the outer wall of the inner groove 11, and the rib 36 extends from the inner groove 11 toward the outer groove 12, but the front end edge of the rib 36 is separated from the inner wall of the outer groove 12. The rib 36 is continuous in the circumferential direction on the outer wall of the inner groove 11, and the inner and outer grooves 13 are divided into the first space 16 and the second space 17 by the rib 36. That is, the rib 36 becomes a partition wall 20 that divides the inner and outer grooves 13 into the first space 16 and the second space 17. In addition, the first space 16 and the second space 17 are connected between the front end edge of the rib 36 and the outer groove 12.

[0068] In the ribs 36 extending in the vertical direction provided in the inner groove 11, there is a possibility that the flow of gas may stagnate near the boundary B3 between the rib 36 and the inner groove 11. Fig.15 As shown, a vent 25 is provided in the boundary area A3 of the rib 36. Here, the "boundary area A3" is an area that is continuous in the circumferential direction along the boundary B3 between the rib 36 and the inner groove 11, and is an area near the boundary B3 between the rib 36 and the inner groove 11. The boundary area A3 may also include the boundary B3. From the purpose of promoting the flow of gas at the boundary B3 between the rib 36 and the inner groove 11, the boundary area A3 of the rib 36 may be in the range of 1 / 6 of the height of the rib 36 from the boundary B3 between the rib 36 and the inner groove 11 (i.e., the dimension from the boundary B3 to the front end edge of the rib 36). Alternatively, the boundary area A3 of the rib 36 may be in the range of 1 / 10 of the height of the rib 36 from the boundary B3 between the rib 36 and the inner groove 11.

[0069] The vent 25 provided on the rib 36 has a first opening 18 opened in the first space 16 and a second opening 19 opened in the second space 17. The vent 25 is arranged so as to be separated from the boundary B3 between the rib 36 and the inner groove 11 toward the front end side of the rib 36 by the amount of the joint formed by welding the inner groove 11 and the rib 36. In addition, the rib 36 extending in the vertical direction is not limited to the rib extending strictly in the vertical direction, and the vent 25 is preferably widely applied to the rib having a vertical component in the extending direction.

[0070] In addition, Fig.14 In the multilayer shell tank 1B shown, a rib 37 is provided on the inner wall of the outer groove 12 in the inner and outer grooves 13. The rib 37 not only functions as a reinforcing member of the outer groove 12, but also functions as a supporting member of the heat insulating member arranged on the inner wall of the outer groove 12. The rib 37 is joined to the inner wall of the outer groove 12, and the rib 37 extends from the outer groove 12 toward the inner groove 11, but the front end edge of the rib 37 is separated from the outer wall of the inner groove 11. The rib 37 is continuous along the circumferential direction of the inner wall of the outer groove 12, and the inner and outer grooves 13 are divided into the first space 16 and the second space 17 by the rib 37. That is, the rib 37 becomes a partition wall 20 that divides the inner and outer grooves 13 into the first space 16 and the second space 17. In addition, the first space 16 and the second space 17 are connected between the front end edge of the rib 37 and the inner groove 11.

[0071] In the ribs 37 extending in the vertical direction in the outer groove 12, there is a possibility that the flow of gas may stagnate at the boundary B4 between the rib 37, the outer groove 12, and the boundary B4. Fig.16 As shown, a vent 25 is provided in the boundary area A4 of the rib 37. Here, the "boundary area A4" is an area that is continuous in the circumferential direction along the boundary B4 between the rib 37 and the outer groove 12, and is an area near the boundary B4 between the rib 37 and the outer groove 12. The boundary area A4 may also include the boundary B4. From the purpose of promoting the flow of gas at the boundary B4 between the rib 37 and the outer groove 12, the boundary area A4 of the rib 37 may be in the range of 1 / 6 of the height of the rib 37 from the boundary B4 between the rib 37 and the outer groove 12 (that is, the dimension from the boundary B4 to the front end edge of the rib 37). Alternatively, the boundary area A4 of the rib 37 may be in the range of 1 / 10 of the height of the rib 37 from the boundary B4 between the rib 37 and the outer groove 12.

[0072] The vent 25 provided on the rib 37 has a first opening 18 opened in the first space 16 and a second opening 19 opened in the second space 17. The vent 25 is arranged so as to be separated from the boundary B4 between the rib 37 and the outer groove 12 toward the front end side of the rib 37 by the amount of the joint formed by welding the outer groove 12 and the rib 37. In addition, the rib 37 extending in the vertical direction is not limited to the rib extending strictly in the vertical direction, and the vent 25 is preferably widely applied to the rib having a vertical component in the extending direction.

[0073] In addition, communication holes for people to pass through may be provided in the ribs 36 and 37. In this case, the ventilation portion 25 may be configured by using the communication holes as in the second embodiment described above.

[0074] 〔Summarize〕

[0075] As described above, the multilayer shell tank 1, 1A, 1B of the first item of the present disclosure comprises: an inner groove 11; an outer groove 12, which surrounds the inner groove 11; and a partition wall 20, which is joined to one of the inner groove 11 and the outer groove 12, and is arranged between the inner groove 11 and the outer groove 12 to divide the groove 13 into a first space 16 and a second space 17, the partition wall 20 has a ventilation portion 25 that connects the first space 16 and the second space 17 in a ventilated manner, the ventilation portion 25 has a first opening 18 arranged in a boundary area A1-A4 along the boundaries B1-B4 between the partition wall 20 and the grooves 11, 12 and opening in the first space 16, and a second opening 19 arranged in the boundary area A1-A4 and opening in the second space 17.

[0076] The multilayer shell tank 1, 1A of the second item of the present disclosure is based on the multilayer shell tank 1, 1A of the first item, wherein the partition wall 20 is joined to the inner groove 11 and the outer groove 12, and the ventilation portion 25 includes at least one of a first ventilation portion 25u having a first opening 18 and a second opening 19 arranged in a boundary area A2 between the inner groove 11 and the partition wall 20, and a second ventilation portion 25b having a first opening 18 and a second opening 19 arranged in a boundary area A1 between the outer groove 12 and the partition wall 20.

[0077] In the multilayer shell tanks 1, 1A, 1B of the first and second items, when the existing gas 32 in the inner and outer grooves 13 is squeezed out by the purge gas 31 in a piston flow manner so as to discharge the existing gas 32 from the inner and outer grooves 13, the retention of the existing gas 32 in the corners where the gas is easily retained, such as the narrow portion 28 generated at the joint between the partition wall 20 and the inner groove 11 and / or the outer groove 12, can be eliminated or prevented. Thus, efficient gas purging can be achieved. Moreover, since no additional device (such as a blower, etc.) is required for eliminating retention, the maintainability and reliability are improved, which can also help reduce costs.

[0078] The multilayer shell tank 1 of the third item of the present disclosure is based on the multilayer shell tank 1 of the first or second item, wherein the ventilation portion 25 is composed of a hole (ventilation hole 250) penetrating the partition wall 20 along the thickness direction, and the partition wall 20 has a traffic hole 26 configured separately from the boundary area A for people to pass through.

[0079] In this way, since the partition wall 20 has the ventilation hole 250 independent of the communication hole 26, the degree of freedom of the position of the ventilation hole 250 is improved.

[0080] The multilayer shell tank 1 of the fourth aspect of the present disclosure is the multilayer shell tank 1 of the third aspect, wherein the communication hole 26 and the vent 25 are separated in the partition wall 20 along a continuous direction of the boundaries B1 - B4 of the partition wall 20 and the grooves 11 , 12 .

[0081] When the ventilation holes 250 are provided on the partition wall 20 independently of the communication holes 26 as described above, it is preferred that the communication holes 26 and the ventilation holes 250 as the ventilation portion 25 are separated in the lateral direction (i.e., circumferential direction) in the partition wall 20. In this way, by staggering the communication holes 26 and the ventilation holes 250 in the partition wall 20 in the circumferential direction, the openings are dispersedly arranged in the circumferential direction, thereby suppressing the reduction in the strength of the partition wall 20 and performing efficient ventilation.

[0082] The multilayer shell tank 1 of the fifth aspect of the present disclosure is the multilayer shell tank 1 of the first or second aspect, wherein the vent 25 is formed of a hole 250 penetrating the partition wall 20 in the thickness direction, and the partition wall 20 has a communication hole 26 continuous with the vent 25 and capable of allowing a person to pass through.

[0083] This can reduce the man-hours required to form the openings that become the vent holes 250 and the communication holes 26 in the partition wall 20 .

[0084] The multilayer shell tank 1 according to a sixth aspect of the present disclosure is the multilayer shell tank 1 according to any one of the first to fifth aspects, wherein the multilayer shell tank 1 further includes a pipe 14 or wiring passing through the vent 25 .

[0085] By using the vent hole 250 as a piping hole or a wiring hole in this manner, it is possible to reduce the man-hours required to separately provide the piping hole or the wiring hole.

[0086] The multilayer shell tank 1A of item 7 of the present disclosure is according to the multilayer shell tank 1A of item 1 or 2, wherein the partition wall 20 has a traffic hole 26 for people to pass through, and the ventilation portion 25 is composed of a tube (for example, a ventilation tube 251) passing through the traffic hole 26, and the tube has a first end portion provided with a first opening 18 and a second end portion provided with a second opening 19.

[0087] Thus, since the ventilation part 25 is constituted by the ventilation tube 251, the degree of freedom of the position of the ventilation part 25 passing through the partition wall 20 is improved. In addition, by using the communication hole 26 as the insertion hole for the ventilation tube 251, the number of openings provided in the partition wall 20 can be reduced.

[0088] The multilayer shell tank 1, 1A, 1B of item 8 of the present disclosure is the multilayer shell tank 1, 1A, 1B of any item of items 1 to 7, wherein the first opening 18 and the second opening 19 are located within a range of 1 / 6 of the height of the partition wall 20 from the boundary B1-B4 between the partition wall 20 and the grooves 11, 12.

[0089] According to the ventilation portion 25 having the first openings 18 and the second openings 19 arranged in the boundary regions A1 - A4 , it is possible to effectively suppress the accumulation of gas in the narrowed portion 28 formed at the boundary B1 - B4 between the grooves 11 , 12 and the partition wall 20 .

[0090] The multilayer shell tank 1 or 1A according to item 9 of the present disclosure is the multilayer shell tank 1 or 1A according to any one of items 1 to 7, wherein the partition wall 20 is cylindrical with the vertical direction as the axial direction and is a supporting member (i.e., the skirt 2) that supports the inner tank 11.

[0091] The structure of the partition wall 20 described above is suitable as the structure of the skirt 2 of the multilayer shell tank 1, 1A. However, the partition wall 20 is not limited to the skirt 2, and any wall that partitions the inner and outer tanks 13 to restrict the flow of gas may be used.

[0092] The multilayer shell tank 1, 1A, 1B of the 10th item of the present disclosure is the multilayer shell tank 1, 1A, 1B according to any of the 1st to 7th items, wherein the first opening 18 and the second opening 19 are arranged away from the ground from the boundary B1-B4 between the grooves 11, 12 and the partition wall 20 across the joint between the grooves 11, 12 and the partition wall 20.

[0093] In this way, it is preferable to arrange the first opening 18 and the second opening 19 at positions closer to the boundary B1 - B4 in the partition wall 20 .

[0094] Preferred embodiments have been described above, but embodiments in which the specific structures and / or functional details of the above embodiments are changed within the scope of the present invention may also be included in the present invention. The above structure may be changed as follows, for example.

[0095] The multilayer shell tank 1 , 1A, 1B of the present embodiment has two shell layers of the inner groove 11 and the outer groove 12 , but may also have a multilayer shell of three or more layers with grooves provided inside the inner groove 11 or outside the outer groove 12 .

[0096] In addition, the multilayer shell tank 1, 1A, 1B of the present embodiment can be a loading and unloading tank or a fuel tank. In addition, in the present disclosure, a structure in which the inner tank 11 is supported by the skirt 2 and can be separated in the space between the inner and outer tanks 13 is taken as an example, but in the case where the inner tank 11 and the outer tank 12 are separated by a supporting structure or a reinforcing member like a double-layer shell square tank and the flow of gas is blocked and stagnated, a vent 25 can also be provided on the supporting structure or the reinforcing member for gas purging.

[0097] 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 above detailed description, various features of the present disclosure are summarized into several embodiments for the purpose of rationalizing the present disclosure. However, 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 multilayer shell tank, comprising: Inner tank; an outer tank surrounding the inner tank; and a partition wall connected to one of the inner groove and the outer groove, the partition wall being arranged between the inner groove and the outer groove to partition the groove into a first space and a second space, The partition wall has a vent portion that connects the first space and the second space in a ventilated manner. The vent portion includes a first opening disposed in a boundary region along a boundary between the partition wall and the groove and opening in the first space, and a second opening disposed in the boundary region and opening in the second space.

2. The multilayer shell tank according to claim 1, wherein: The partition wall is engaged with the inner groove and the outer groove, The ventilation portion includes at least one of a first ventilation portion having the first opening and the second opening arranged in the boundary area between the inner groove and the partition wall, and a second ventilation portion having the first opening and the second opening arranged in the boundary area between the outer groove and the partition wall.

3. The multilayer shell tank according to claim 1 or 2, wherein: The ventilation portion is composed of a hole penetrating the partition wall in the thickness direction. The partition wall has a traffic hole that is arranged separately from the boundary area and through which people can pass.

4. The multilayer shell tank according to claim 3, wherein: The communication hole and the vent are separated in the partition wall along a continuous direction of a boundary between the partition wall and the groove.

5. The multilayer shell tank according to claim 1 or 2, wherein: The ventilation portion is composed of a hole penetrating the partition wall in the thickness direction. The partition wall has a traffic hole which is continuous with the vent and through which people can pass.

6. The multilayer shell tank according to any one of claims 1 to 5, wherein: The multilayer shell tank further includes piping or wiring passing through the vent portion.

7. The multilayer shell tank according to claim 1 or 2, wherein: The partition wall has a traffic hole for people to pass through. The ventilation portion is constituted by a tube passing through the communication hole, and the tube has a first end portion provided with the first opening and a second end portion provided with the second opening.

8. The multi-layer shell tank according to claim 2, wherein: The first opening and the second opening are located within a range of 1 / 6 of the height of the partition wall from the boundary of the partition wall.

9. The multilayer shell tank according to any one of claims 1 to 8, wherein: The partition wall has a cylindrical shape with an up-down direction as an axial direction, and is a supporting member that supports the inner tank.

10. The multilayer shell tank according to any one of claims 1 to 9, wherein: The first opening and the second opening are arranged apart from a boundary between the groove and the partition wall via a junction between the groove and the partition wall.

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