Tank

Abstract

To provide a tank, which is configured so that irregular deformation can be suppressed from occurring in a liner.SOLUTION: A tank (10) is provided with a peripheral wall (11) forming a storage space (S) for liquid (L) and a liner (18) coating an inner surface side of a heat insulation layer (17) provided on the inner surface side of the peripheral wall. The liner comprises a plurality of first-to-fourth corrugations (31-34) respectively. In the liner are formed surrounded regions (35) surrounded by respective one sides of the first-to-fourth corrugations, where areas of the surrounded regions are smaller than areas of the other regions. The first and the second corrugations are provided in parallel to the first direction to separate from each other by a predetermined interval in a second direction which is different from the first direction and form the surrounded regions while extending in the opposite directions from each other, from one ends thereof. The third and the fourth corrugations are provided in parallel to the second direction to separate by a predetermined interval in the first direction and form the surrounded regions while extending in the opposite directions from each other, from one ends thereof.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a tank for storing liquid.

Background Art

[0002] In various facilities and sites, large tanks for storing liquids are used. For example, Patent Document 1 discloses an underground storage tank in which a heat insulating material is stretched over the entire inner surface of an outer tank, and an inner tank having a membrane structure is provided on the entire inner surface of the heat insulating material. Such a membrane structure includes a corrugation in a horizontal posture, a corrugation in a vertical posture that intersects non-crosswise with respect to the central portion thereof, and a corrugation in a vertical posture in which the central portion is located at both ends of the corrugation in a horizontal posture.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In Patent Document 1, the flat plate portions surrounded by two-direction adjacent corrugations that directly meet when receiving a temperature change turn and contract in opposite directions to each other, thereby achieving the stabilization of the entire membrane. On the other hand, for example, when a high-temperature liquid is stored in the storage tank and the membrane expands, at the meeting portion of the two-direction adjacent corrugations, an irregular deformation occurs due to buckling, and the possibility of the membrane breaking becomes high.

[0005] In view of this point, the present invention is made, and one of the objects is to provide a tank capable of preventing an irregular deformation from occurring in a liner at a portion where corrugations extending in different directions approach each other.

Means for Solving the Problems

[0006] A tank according to one aspect of the present invention includes a peripheral wall and a bottom wall that form a liquid storage space, a heat insulation layer provided on the inner surface side of the peripheral wall and the bottom wall, and a liner that covers the inner surface side of the heat insulation layer. The liner includes a plurality of first to fourth corrugations respectively. In the liner, an enclosed area is formed by surrounding one end side of each of the first to fourth corrugations, and the enclosed area has an area smaller than other areas. The first corrugation and the second corrugation are parallel to a first direction and are provided at a predetermined interval in a second direction different from the first direction, and form the enclosed area while the extending directions from their respective one ends are opposite to each other. The third corrugation and the fourth corrugation are parallel to the second direction and are provided at a predetermined interval in the first direction, and form the enclosed area while the extending directions from their respective one ends are opposite to each other. One end of the first corrugation is disposed in the vicinity of either one of the third corrugation and the fourth corrugation via a gap. One end of the second corrugation is disposed in the vicinity of the other one of the third corrugation and the fourth corrugation via a gap. One end of the third corrugation is disposed in the vicinity of either one of the first corrugation and the second corrugation via a gap. One end of the fourth corrugation is disposed in the vicinity of the other one of the first corrugation and the second corrugation via a gap.

Advantages of the Invention

[0007] According to the present invention, since the enclosed area and the gaps are formed by the first to fourth corrugations as described above, the thermal strain of the liner can be absorbed by the bending deformation of the corrugations in both the first and second directions. Thereby, it is possible to prevent the liner from being deformed irregularly in the enclosed area and its periphery, which is a portion where the corrugations extending in the first and second directions approach each other.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, a tank according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Here, the present invention is not limited to the following embodiments, and can be appropriately modified and implemented within the scope of not changing the gist thereof. In the following figures, for convenience of explanation, some configurations may be omitted. Also, in this specification and the claims, unless otherwise specified, "inside", "inner side", "inward", and "inward direction" are directions toward the storage space side of the tank, and "outside", "outer side", "outward", and "outward direction" are the opposite sides. However, the directions of the respective configurations in the following embodiments are merely examples, and can be changed to any direction.

[0010] FIG. 1 is a longitudinal sectional view of a part of a tank according to an embodiment. In FIG. 1, a tank 10 having a structure generally used in various facilities is illustrated as an example. The tank 10 includes a cylindrical peripheral wall 11 oriented in the vertical direction and a bottom wall 12 provided at the lower part of the peripheral wall 11 and oriented generally in the horizontal direction, and a storage space S for storing various liquids L is formed inside. The peripheral wall 11 and the bottom wall 12 are made of structural steel plates, and examples of the structural steel plates include general carbon steels (for example, SM490A) with little strength reduction.

[0011] In the tank 10, a roof 13 is provided so as to cover the upper part of the peripheral wall 11. In FIG. 1, it is formed in a dome shape, but various modifications are possible, such as forming it in a hammer shape or in a flat shape with a water gradient. Further, the tank 10 is supported on a foundation slab 15 provided on the ground surface.

[0012] The tank 10 further includes a heat insulation layer 17 provided on the inner surface side of the peripheral wall 11 and the bottom wall 12, and a liner 18 covering the inner surface side of the heat insulation layer 17. The liner 18 is formed by arranging a plurality of plate-like liner forming bodies 18a. More specifically, each liner forming body 18a has a planar shape formed in a square (rectangular) shape. The liner 18 is configured by arranging the liner forming bodies 18a in two orthogonal directions parallel to two sides sandwiching the corners of each liner forming body 18a in the vertical and horizontal directions.

[0013] Here, in the following, the functions of the heat insulation layer 17 and the liner 18 will be described by taking as an example the case where the liquid L to be stored is a molten salt serving as a heat storage material. Such a molten salt can be exemplified by a mixed salt of NaNO3 and KNO3 that is stored and used in a temperature range of about 300 to 600°C as a chemically inert nitrate-based molten salt.

[0014] The heat insulation layer 17 has a heat insulation function and a support function of transmitting the internal pressure caused by the liquid L stored in the storage space S to the peripheral wall 11 and the bottom wall 12.

[0015] The heat insulation function keeps the surface temperatures of the peripheral wall 11, the bottom wall 12, and the surface of the foundation slab 15 that supports the bottom wall 12 at a constant temperature and keeps the liquid L warm. By keeping the surface temperatures of the peripheral wall 11, the bottom wall 12, and the foundation slab 15 at a constant temperature, a decrease in their strength is suppressed. Thereby, the required plate thickness of the structural steel plates of the peripheral wall 11 and the bottom wall 12 can be rationalized.

[0016] The support function is a function of transmitting the internal pressure by the liquid L to the peripheral wall 11 and the bottom wall 12 via the liner 18 and the heat insulation layer 17. If the peripheral wall 11 and the bottom wall 12 are in close contact via the liner 18 and the heat insulation layer 17, the internal pressure can be transmitted as a surface external force. The heat insulation layer 17 is made of a material that has sufficient compressive strength against the pressure from the inside and has a sufficiently large rigidity so that the liner 18 is not damaged by deformation.

[0017] The shape of the heat insulation layer 17 is a vertically long strip shape with a rounded shape of the cylindrical peripheral wall 11, and by attaching it, cracking due to internal pressure is prevented. The heat insulation layer 17 is supported by the peripheral wall 11 or the bottom wall 12, and the support portion is preferably made as large as possible in a plate shape to reduce the heat path as much as possible.

[0018] By using, for example, a calcium silicate-based heat insulation board (heat insulating material) for the heat insulation layer 17, the above heat insulation function and support function can be achieved simultaneously even at high temperatures.

[0019] The functions of the liner 18 are to withstand corrosion by the liquid L that becomes molten salt and to exhibit the liquid tightness of the liquid L. The liner 18 is a layer made of a highly corrosion-resistant steel material (for example, stainless steel such as SUS316).

[0020] To withstand the corrosion of the liquid L, the plate thickness of the liner 18 is set to a plate thickness that can withstand corrosion during the service period. To ensure the liquid tightness of the liquid L, the liner 18 is a closed layer without leakage.

[0021] The liner 18 is supported by the heat insulation layer 17 as described above and is also supported by the plurality of peripheral wall side support mechanisms 20 and bottom wall side support mechanisms 22.

[0022] FIG. 2 is a view of a part of the liner of the embodiment as seen from the inside. FIG. 2 illustrates, for explanatory purposes, a liner forming body 18a arranged in three rows each in the vertical and horizontal directions as a part of the liner 18 provided along the peripheral wall 11. As shown by the dotted line in FIG. 2, the peripheral wall side support mechanism 20 is provided at each of the corner portions that are the four corners of each liner forming body 18a in the liner 18. Therefore, the peripheral wall side support mechanism 20 is provided in a grid pattern at predetermined intervals in the vertical and horizontal directions. The peripheral wall side support mechanism 20 is composed of steel materials or steel plates that connect the inner surface of the peripheral wall 11 and the outer surface of the liner 18, and has a function of supporting the liner 18 with respect to the peripheral wall 11.

[0023] The bottom wall side support mechanism 22 is composed of, for example, steel materials or steel plates provided so as to protrude from the inner surface of the liner 18 and be embedded in the heat insulating layer 17. The bottom wall side support mechanism 22 can be provided, for example, in a grid pattern at predetermined intervals in two orthogonal directions when viewed from above, or can be provided at predetermined intervals along a plurality of concentric circles.

[0024] Here, in the liner 18, during the operation of storing the liquid L in the storage space S, it becomes hotter and thermally expands compared to the time of constructing the tank 10. On the other hand, the liner forming body 18a forming the liner 18 is in a state where its displacement is restricted by the respective support mechanisms 20 and 22. In order to absorb the thermal strain caused by such thermal expansion, the inventor considered adopting a corrugation structure in the form of a lattice for the liner 18. However, when adopting the above corrugation structure, local buckling may occur in the intersection region of the lattice due to thermal strain, and the liner 18 may break. Therefore, the liner 18 of the present embodiment adopts a configuration that can avoid buckling that causes breakage while adopting the corrugation structure. Hereinafter, the corrugation structure of the liner 18 in the present embodiment will be described.

[0025] FIG. 3A is a view of the liner forming body of the embodiment as seen from the inside. FIG. 3 is an enlarged view of the liner forming body 18a located in the upper left among the nine liner forming bodies 18a illustrated in FIG. 2. First, the corrugation structure of the liner forming body 18a will be described.

[0026] As shown in FIG. 3A, the liner forming body 18a includes four corrugations, namely, a first corrugation 31, a second corrugation 32, a third corrugation 33, and a fourth corrugation 34.

[0027] Each of the corrugations 31 to 34 extends linearly. One end of each is disposed in the central region within the plane of the liner forming body 18a, and the other end side is disposed on the outer peripheral edge that forms the four sides of the liner forming body 18a. Specifically, the first corrugation 31 is parallel to the vertical direction which is the first direction, extends upward with one end being the lower end, and the other end being the upper end. The second corrugation 32 is parallel to the vertical direction like the first corrugation 31, extends downward with one end being the upper end and the extending direction from this one end being opposite to that of the first corrugation 31, and the other end being the lower end. The third corrugation 33 is parallel to the left - right direction which is the second direction, extends rightward with one end being the left end, and the other end being the right end. The fourth corrugation 34 is parallel to the left - right direction like the third corrugation 33, extends leftward with one end being the right end and the extending direction from this one end being opposite to that of the third corrugation 33, and the other end being the left end. In the present embodiment, as described above, the first direction is the vertical direction, the second direction is the left - right direction different from the first direction, and the angle formed by the first and second directions is set to be a right angle.

[0028] The first corrugation 31 and the second corrugation 32 are provided at a predetermined interval in the left - right direction. The third corrugation 33 and the fourth corrugation 34 are provided at a predetermined interval in the vertical direction.

[0029] One end of the first corrugation 31 is disposed above the third corrugation 33 with a gap therebetween and near the middle portion in the extending direction. One end of the second corrugation 32 is disposed below the fourth corrugation 34 with a gap therebetween and near the middle portion in the extending direction. One end of the third corrugation 33 is disposed to the right of the second corrugation 32 with a gap therebetween and near the middle portion in the extending direction. One end of the fourth corrugation 34 is disposed to the left of the first corrugation 31 with a gap therebetween and near the middle portion in the extending direction. Note that the lengths of the corrugations 31 to 34 formed in the liner forming body 18a are set to be the same.

[0030] In the in-plane center of the liner forming body 18a, a surrounding region 35 is formed which is surrounded in a substantially square shape within a predetermined range on one end side of each of the first to fourth corrugations 31 to 34. In the liner forming body 18a, the surrounding region 35 has an area smaller than that of the main region 36 which is the region other than the surrounding region 35. The surrounding region 35 and the main region 36 are respectively provided with a flat surface shape or a surface shape curved according to the curvature of the cylindrical peripheral wall 11.

[0031] One end sides of the first and second corrugations 31 and 32 respectively overlap in the left-right direction so as to sandwich the surrounding region 35 from the left and right directions, and such an overlap forms the first lap portion 37. One end sides of the third and fourth corrugations 33 and 34 respectively overlap in the up-down direction so as to sandwich the surrounding region 35 from the up and down directions, and such an overlap forms the second lap portion 38.

[0032] FIG. 3B is a sectional view taken along arrow A of FIG. 3A, and FIG. 3C is an enlarged view of part B of FIG. 3B. As shown in FIGS. 3B and 3C, the first and second corrugations 31, 32 are formed in a pleated structure that bulges inward. More specifically, the cross-sectional shape perpendicular to the extending direction is formed in a shape that bulges like a dome or a semi-circular arc. Although not shown, the cross-sectional shape perpendicular to the extending direction of the third and fourth corrugations 33, 34 is also formed in the same manner as the first and second corrugations 31, 32. Each of the corrugations 31 to 34 can absorb the thermal strain of the liner 18 by elastically deforming so that the height and width of the bulge change. The formation of the first to fourth corrugations 31 to 34 in the liner forming body 18a can be exemplified by press working.

[0033] Returning to FIG. 2, since the liner 18 is formed by a plurality of liner forming bodies 18a, it includes a plurality of each of the first to fourth corrugations 31 to 34. Further, the liner 18 includes a plurality of first patterns P1 and a plurality of second patterns P2, and only one of the patterns P1, P2 is provided for each liner forming body 18a.

[0034] The first pattern P1 and the second pattern P2 are common in that they are each formed including the surrounding region 35 and each of the first to fourth corrugations 31 to 34 forming the surrounding region 35, while their directions are different. Specifically, the second pattern P2 is arranged by inverting the first corrugation 31 and the second corrugation 32 of the first pattern P1 in the vertical direction and inverting the third corrugation 33 and the fourth corrugation 34 of the first pattern P1 in the horizontal direction.

[0035] Also, in the second pattern P2, one end (upper end) of the first corrugation 31 is disposed below the fourth corrugation 33 with a gap therebetween and near the middle portion in the extending direction. One end (lower end) of the second corrugation 32 is disposed above the third corrugation 33 with a gap therebetween and near the middle portion in the extending direction. One end (right end) of the third corrugation 33 is disposed to the left of the first corrugation 31 with a gap therebetween and near the middle portion in the extending direction. One end (left end) of the fourth corrugation 34 is disposed to the right of the second corrugation 32 with a gap therebetween and near the middle portion in the extending direction.

[0036] In the liner 18, the first pattern P1 and the second pattern P2 are alternately arranged in the vertical direction, and also the first pattern P1 and the second pattern P2 are alternately arranged in the horizontal direction. Therefore, the liner 18 includes a plurality of two types of liner forming bodies 18a, namely, a liner forming body 18a in which the first pattern P1 is formed and a liner forming body 18a in which the second pattern P2 is formed, and these two types of liner forming bodies 18a are configured to be arranged in a staggered pattern.

[0037] In the first pattern P1 and the second pattern P2 adjacent to each other in the vertical direction, the other ends of the respective first corrugations 31 or the other ends of the respective second corrugations 32 are continuous. Specifically, the upper end of the first corrugation 31 of the first pattern P1 is continuous with the lower end of the first corrugation 31 in the second pattern P2 adjacent to the upper side of the first pattern P1. Also, the lower end of the second corrugation 32 of the first pattern P1 is continuous with the upper end of the second corrugation 32 in the second pattern P2 adjacent to the lower side of the first pattern P1.

[0038] The other ends of the respective third corrugations 33 or the other ends of the respective fourth corrugations 34 are connected in the first pattern P1 and the second pattern P2 adjacent to each other in the left-right direction. Specifically, the right end of the third corrugation 33 of the first pattern P1 and the left end of the third corrugation 33 in the second pattern P2 adjacent to the first pattern P1 in the right direction are connected. Also, the left end of the fourth corrugation 34 of the first pattern P1 and the right end of the fourth corrugation 34 in the second pattern P2 adjacent to the first pattern P1 in the left direction are connected.

[0039] As described above, the other ends of the corrugations 31 to 34 are formed at the same position between the different patterns P1 and P2 and are connected to each other. As a result, the corrugations 31 to 34 extend linearly across the different patterns P1 and P2.

[0040] In the above description, the liner 18 along the peripheral wall 11 has been illustrated and described. However, the liner 18 along the bottom wall 12 can be similarly configured by changing the direction from the vertical direction to the horizontal direction.

[0041] Subsequently, the deformation when the liner 18 thermally expands will be described by comparing the corrugation structure of the above-described embodiment with the conventional corrugation structure.

[0042] Figure 4A is an enlarged view of the surrounding area of Figure 3A and its periphery. Figures 4B to 4D are explanatory cross-sectional views showing an example of the state where the liner in the embodiment is thermally expanded. Figure 4B is a cross-sectional view taken along the arrow a in Figure 4A, Figure 4C is a cross-sectional view taken along the arrow b in Figure 4A, and Figure 4D is a cross-sectional view taken along the arrow c in Figure 4A.

[0043] When the liner 18 thermally expands, due to the generation of thermal strain in the main region 36, a lateral force is applied to the first corrugation 31 and the second corrugation 32 from the main region 36 as indicated by the arrow ST in FIGS. 4B and 4D. When such a force is applied, the first corrugation 31 and the second corrugation 32 elastically deform so as to increase the height in the inner and outer directions and reduce the lateral width, making it possible to absorb the thermal strain.

[0044] Also, as shown in FIG. 4C, in the formed portion of the surrounding region 35, when a lateral force indicated by the arrow ST is applied due to the thermal strain of the main region 36, both the first and second corrugations 31, 32 forming the first wrap portion 37 elastically deform to absorb the thermal strain.

[0045] In each of the patterns P1, P2 (see FIG. 2) of the embodiment, in the vertical direction, the first corrugation 31, the first wrap portion 37, and the second corrugation 32 are continuously formed without interruption. Therefore, thermal strain can be absorbed over the entire range in the vertical direction of each of the patterns P1, P2.

[0046] Furthermore, although not shown, in the third corrugation 33, the second wrap portion 38, and the fourth corrugation 34, a vertical force is applied from the main region 36. At this time, although the vertical and lateral directions are changed, elastic deformation similar to the above occurs in the third corrugation 33 and the fourth corrugation 34, making it possible to absorb the vertical thermal strain.

[0047] In each of the patterns P1, P2 (see FIG. 2) of the embodiment, in the lateral direction, the third corrugation 33, the second wrap portion 38, and the fourth corrugation 34 are continuously formed without interruption. Therefore, thermal strain can be absorbed over the entire range in the lateral direction of each of the patterns P1, P2.

[0048] FIG. 5A is a diagram similar to FIG. 4A of the conventional corrugation structure. The conventional corrugation structure shown in FIG. 5A includes, as one pattern, a horizontal corrugation 101 extending parallel in the left - right direction, and an upper corrugation 102 and a lower corrugation 103 extending parallel in the up - down direction and arranged on the same straight line. One end (lower end) of the upper corrugation 102 is arranged above the horizontal corrugation 101 with a gap therebetween and near the middle of the extending direction. One end (upper end) of the lower corrugation 103 is arranged below the horizontal corrugation 101 with a gap therebetween and near the middle of the extending direction. The cross - sectional shape orthogonal to the extending direction of each of the corrugations 101 - 103 is the same as that of each of the corrugations 31 - 34 in the above - described embodiment.

[0049] FIGS. 5B and 5C are explanatory cross - sectional views showing an example of the state where the liner is thermally expanded in the conventional corrugation structure. FIG. 5B is a cross - sectional view taken along the d arrow direction of FIG. 5A, and FIG. 5C is a cross - sectional view taken along the e arrow direction of FIG. 5A. As shown in FIG. 5B, in the conventional corrugation structure, when a force from the left - right direction indicated by the arrow ST is applied to the upper corrugation 102 due to thermal strain, the upper corrugation 102 elastically deforms and can absorb the thermal strain. Also, in the lower corrugation 103, similarly to the upper corrugation 102, it can absorb the thermal strain.

[0050] On the other hand, in the conventional corrugation structure, there is a gap between each one end of the upper corrugation 102 and the lower corrugation 103 and the horizontal corrugation 101, and in the up - down direction, the corrugation becomes discontinuous and breaks. For this reason, when a force from the left - right direction is applied to such a gap portion, it cannot elastically deform to absorb the thermal strain, and as shown in FIG. 5C, an irregular deformation C with an acute angle occurs due to buckling, and as a result, there is a problem that the liner breaks.

[0051] In this regard, in the configuration of the embodiment, in each pattern P1 and P2, as described above, each of the corrugations 31 to 34 and each of the wrap portions 37 and 38 are continuously formed without interruption in the vertical and horizontal directions. As a result, the thermal strain can be absorbed by the bending deformation of each of the corrugations 31 to 34 in the vertical and horizontal directions, and it is possible to prevent an irregular deformation C as in the conventional case from occurring in the surrounding region 35 and its periphery of the liner forming body 18a. Therefore, it is possible to avoid the breakage of the liner 18 as in the conventional case, and the state of the liquid L stored in the storage space S can be stably maintained for a long time even when the liquid L becomes high temperature.

[0052] In the above description, the case where thermal strain occurs in a direction parallel to the vertical and horizontal directions has been described. However, even when thermal strain occurs in a direction angularly displaced with respect to such a direction, the thermal strain can be absorbed so as to be dispersed in the vertical and horizontal directions.

[0053] The liner forming body 18a can absorb thermal strain by the first wrap portion 37 and the second wrap portion 38 where two of the corrugations 31 to 34 overlap in the vertical and horizontal directions around the surrounding region 35. Although a large force is likely to be applied to the in-plane center of the liner forming body 18a from various directions, since the first wrap portion 37 and the second wrap portion 38 are formed at the in-plane center, it is possible to efficiently absorb thermal strain.

[0054] Further, in each of the corrugations 31 to 34, different corrugations 31 to 34 are arranged so as to approach each other via a gap or the surrounding region 35 without directly intersecting or being connected to each other. Therefore, it is possible to suppress the generation of a locally large stress due to thermal strain. Accordingly, the thermal strain can be sufficiently absorbed by the elastic deformation of each of the corrugations 31 to 34 around the surrounding region 35, and it is possible to prevent an irregular deformation C as in the conventional case from occurring.

[0055] In the above-described embodiment, in the liner 18, the corrugations 31 to 34 are arranged by the first pattern P1 and the second pattern P2 that face different directions from each other, and the patterns P1 and P2 are alternately arranged in the vertical and horizontal directions. As a result, the other ends of the corrugations 31 to 34 of the patterns P1 and P2 adjacent to each other in the vertical and horizontal directions are connected and arranged in a straight line, making it easier to have regularity in elastic deformation due to thermal strain and efficiently absorb thermal strain.

[0056] Further, since the angle formed by the vertical direction as the first direction and the horizontal direction as the second direction is set to a right angle, the layout design of the corrugations 31 to 34 can be easily performed. Furthermore, by extending the two sides sandwiching the corner portion of the liner forming body 18a in parallel in the vertical and horizontal directions, it is possible to contribute to the facilitation of the layout design of the corrugations 31 to 34.

[0057] In addition, since one of the first pattern P1 and the second pattern P2 is provided in the liner forming body 18a, it becomes easier to easily perform the layout design of the corrugations 31 to 34 in which the surrounding region 35 is arranged at the center in the plane of the liner forming body 18a.

[0058] The embodiment of the present invention is not limited to the above-described embodiment, and various changes, substitutions, and modifications may be made without departing from the spirit of the technical idea of the present invention. Furthermore, if the technical idea of the present invention can be realized in another way by technological progress or another derived technology, the method may be used for implementation. Therefore, the scope of the claims covers all embodiments that can be included within the scope of the technical idea of the present invention.

[0059] In the above-described embodiment, the case where the liquid L to be stored is a heat storage material (molten salt) has been described, but it may be changed as long as it is a liquid, such as using a liquid fossil fuel such as liquefied natural gas. When the liquid L to be stored is at a lower temperature than the outside air of the tank 10, the heat insulation function can suppress the temperature rise of the liquid L.

[0060] In the above-described embodiment, only one of the patterns P1 and P2 is provided for each liner forming body 18a. However, the present invention is not limited to this, and for example, it may be changed as shown in FIGS. 6 and 7. FIG. 6 is a view similar to FIG. 2 in the modification. FIG. 7 is a view similar to FIG. 3A in the modification.

[0061] In the modification shown in FIGS. 6 and 7, two of each of the first pattern P1 and the second pattern P2 are provided for one liner forming body 18a. In FIGS. 6 and 7, the first pattern P1 is formed at the upper left and lower right of the liner forming body 18a, and the second pattern P2 is formed at the upper right and lower left of the liner forming body 18a.

[0062] As shown in FIG. 7, in the liner forming body 18a, the first corrugations 31 of the first pattern P1 at the lower right and the second pattern P2 at the upper right are continuous in a straight line, and the second corrugations 32 of the first pattern P1 at the upper left and the second pattern P2 at the lower left are continuous in a straight line. Also, the third corrugations 33 of the first pattern P1 at the upper left and the second pattern P2 at the upper right are continuous in a straight line, and the fourth corrugations 34 of the first pattern P1 at the lower right and the second pattern P2 at the lower left are continuous in a straight line.

[0063] According to the modification shown in FIGS. 6 and 7, all the liner forming bodies 18a can have the same shape, and the management burden and work burden can be reduced as compared with the case where a plurality of types of liner forming bodies 18a are arranged side by side.

[0064] In the above-described embodiment, the liner forming body 18a may be formed in a rectangular shape, and the number of formations of the patterns P1 and P2 arranged in the left-right direction and the number of formations of the patterns P1 and P2 arranged in the up-down direction may be different. Further, in the above-described embodiment, the lengths of the corrugations 31 to 34 are the same for each of the patterns P1 and P2, but they may be different lengths.

[0065] Also, in the above embodiment, although the surrounding area 35 is formed in a square shape, it may be changed to a rectangular shape or the like. For example, when the surrounding area 35 is formed in a vertically long rectangular shape, the vertical width of the first wrap portion 37 becomes longer than the horizontal width of the second wrap portion 38.

[0066] Also, the first direction, which is the extending direction of the first corrugation 31 and the second corrugation 32, is set as the vertical direction, and the second direction, which is the extending direction of the third corrugation 33 and the fourth corrugation 34, is set as the horizontal direction. However, as long as they are different from each other, they may be changed. Therefore, by inclining the first direction by a predetermined angle with respect to the vertical direction and inclining the second direction by a predetermined angle with respect to the horizontal direction, the angle formed by the first direction and the second direction may be set to other than a right angle. Further, the first direction and the second direction do not have to be parallel to the two sides sandwiching the corner portion of the liner forming body 18a. However, setting the first direction and the second direction as in the above embodiment is advantageous in that the layout design of each corrugation 31 to 34 can be facilitated and heat strain can be easily absorbed.

Explanation of Reference Numerals

[0067] 10: Tank 11: Peripheral Wall 12: Bottom Wall 17: Heat Insulation Layer 18: Liner 18a: Liner Forming Body 31: First Corrugation 32: Second Corrugation 33: Third Corrugation 34: Fourth Corrugation 35: Surrounding Area 37: First Wrap Portion 38: Second Wrap Portion L: Liquid P1: First Pattern P2: Second Pattern S: Storage Space

Claims

1. A tank comprising a peripheral wall and a bottom wall that form a liquid storage space, a heat insulation layer provided on the inner surface side of the peripheral wall and the bottom wall, and a liner that covers the inner surface side of the heat insulation layer, wherein the liner includes a plurality of first to fourth corrugations respectively, a surrounding region is formed in the liner at one end side of each of the first to fourth corrugations, and the surrounding region has an area smaller than other regions, the first corrugation and the second corrugation are parallel to a first direction and are provided at a predetermined interval in a second direction different from the first direction, and while the extending directions from their respective one ends are opposite directions, they form the surrounding region, the third corrugation and the fourth corrugation are parallel to the second direction and are provided at a predetermined interval in the first direction, and while the extending directions from their respective one ends are opposite directions, they form the surrounding region, one end of the first corrugation is disposed in the vicinity of either one of the third corrugation and the fourth corrugation via a gap, one end of the second corrugation is disposed in the vicinity of the other one of the third corrugation and the fourth corrugation via a gap, one end of the third corrugation is disposed in the vicinity of either one of the first corrugation and the second corrugation via a gap, one end of the fourth corrugation is disposed in the vicinity of the other one of the first corrugation and the second corrugation via a gap.

2. The tank according to claim 1, wherein an angle formed by the first direction and the second direction is set to be a right angle.

3. One end sides of the first corrugation and the second corrugation respectively overlap in the second direction to form a first lap portion, The tank according to claim 1 or claim 2, wherein one end sides of the third corrugation and the fourth corrugation respectively overlap in the first direction to form a second lap portion.

4. The tank according to claim 3, wherein the surrounding region is sandwiched from the second direction by the first lap portion and is sandwiched from the first direction by the second lap portion.

5. The liner includes a plurality of first patterns including the surrounding region and each of the first to fourth corrugations that form the surrounding region, The surrounding region in which the first corrugation and the second corrugation of the first pattern are inverted in the first direction, and the third corrugation and the fourth corrugation of the first pattern are inverted in the second direction and arranged, and a plurality of second patterns each including one of the first to fourth corrugations are provided. The tank according to claim 1 or claim 2, wherein the first pattern and the second pattern are alternately arranged in the first direction and alternately arranged in the second direction.

6. In the first pattern and the second pattern adjacent to each other in the first direction, the other ends of the respective first corrugations or the other ends of the respective second corrugations are connected in series. The tank according to claim 5, wherein in the first pattern and the second pattern adjacent to each other in the second direction, the other ends of the respective third corrugations or the other ends of the respective fourth corrugations are connected in series.

7. The liner is formed by arranging a plurality of liner forming bodies having a rectangular shape side by side. The tank according to claim 6, wherein the first direction and the second direction extend parallel to two sides sandwiching a corner of the liner forming body.

8. The tank according to claim 7, wherein at least one of the first pattern and the second pattern is provided on the liner forming body.

9. The tank according to claim 7, wherein two of each of the first pattern and the second pattern are provided on the liner forming body.

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