Conformal storage tank

Abstract

The present disclosure relates to a tank configured to preserve a pressurized substance, the tank comprising a chamber (110) configured to enclose the pressurized substance and provide a seal between the pressurized substance and an ambient atmosphere, an inner skeleton (120) disposed within the chamber (110) and coupled to the chamber (110) to provide structural support to the chamber (110), where the inner skeleton (120) comprises a plurality of coupled support members (130), where the support members (130) are configured to support the pressurized substance. The plurality of coupled support members (130) includes at least a first set of support members (131) having sides formed from a sheet material, where each support member of the support members (131) in the first set includes an internal asymmetric tetrahedral structure formed from sides, where the support members (131) in the first set are coupled to each other, and where the support members (131) in the first set are coupled to each other. Each side face of the asymmetric tetrahedral structure is in the shape of a non-equilateral triangle.

Description

Technical Field

[0001] The present disclosure relates to a conformable storage tank for storing a substance, particularly a pressurized substance. Background Art

[0002] A container configured to store a substance, particularly a container configured to store a substance at a pressure different from the ambient atmosphere, is generally referred to as a storage tank. The difference between the pressure inside the storage tank and the ambient atmosphere results in forces acting on the walls of the storage tank.

[0003] An example of a substance that is typically stored at a pressure higher than the ambient atmosphere is hydrogen. However, the fundamental problem applies to any pressurized substance, regardless of whether it is in a solid, liquid, or gaseous state.

[0004] If a pressure higher than the ambient atmosphere is applied to the substance, the storage tank would theoretically assume an approximately spherical shape.

[0005] For practical reasons, it is desirable for the storage tank to conform to a desired external geometry. Typically, it is to conform to voids in mechanical structures such as the wing of an aircraft or the chassis of a road vehicle, which are readily available for the storage tank.

[0006] To ensure that the storage tank fits into the available voids and continuously conforms to the external geometry required by the voids, additional support features are needed. The support features generally support the walls of the storage tank to minimize deformation when forces act on the walls of the storage tank.

[0007] Traditional solutions may include internal strengthening structures for preventing the walls from collapsing when forces act on the walls of the storage tank. An example is shown in WO2022 / 053585. Another example can be found in WO 2013 / 073724A1, which describes large marine storage tanks with internal girders, bulkheads, etc. Another example is described in EP 1 907 750 B1, which discloses connecting rods between opposite walls. Another example is shown in US 9 234 626 B2, which discloses a storage tank with spherical units. Another example is shown in US 9 234 626 B2, which discloses a storage tank with polyhedral units. More examples can be found in EP1723053B1, KR101701765B1, and KR101935919. However, the problem with such traditional solutions is that when the strengthening structures generally rely on beams or trusses to transfer forces at selected points on the walls of the storage tank, the material of the storage tank locally bears high material stresses.

[0008] Other traditional solutions may include internal structures to prevent weight offset due to liquid sloshing, for example, as described in EP1137577B1. However, these solutions do not focus on the structural integrity of the storage tank.

[0009] Accordingly, an improved storage tank is needed to store pressurized substances. SUMMARY OF THE INVENTION

[0010] The subject matter described herein overcomes the above disadvantages. Other advantageous embodiments of the present invention are described.

[0011] According to a first aspect of the present invention, the object of the present invention is achieved by a storage tank configured to store pressurized substances. The storage tank includes a chamber configured to enclose the pressurized substance and provide a seal between the pressurized substance and the surrounding atmosphere, and an internal skeleton disposed within the chamber and connected to the chamber to provide structural support to the chamber. The internal skeleton includes a plurality of connected support members, and the plurality of connected support members includes at least a first group of support members having sides formed of sheets. Each support member in the first group includes an internal asymmetric tetrahedral structure formed by the sides, and each side of the asymmetric tetrahedral structure is in the shape of a non-equilateral triangle.

[0012] In an embodiment of the first aspect, the chamber is configured to have a shape conforming to a desired external geometry intended to surround the chamber.

[0013] In an embodiment of the first aspect, the internal skeleton further includes a second group of support members, and each support member in the second group includes an internal polyhedral structure other than the asymmetric tetrahedral structure.

[0014] In an embodiment of the first aspect, each of the plurality of connected support members has equal external dimensions.

[0015] In an embodiment of the first aspect, at least some of the plurality of connected support members have different external dimensions.

[0016] In an embodiment of the first aspect, the internal skeleton is connected to the chamber by attaching one or more sheets of the first group of support members to the chamber.

[0017] In an embodiment of the first aspect, one or more sheets of the first group are attached to the chamber along the sides of the one or more sheets facing the chamber.

[0018] In an embodiment of the first aspect, one or more sheets are attached to the chamber by welding and / or gluing and / or brazing and / or melting and / or additive manufacturing and / or additive deposition.

[0019] In an embodiment of the first aspect, the storage tank further includes a sheath arranged to form a layer surrounding the outside of the chamber.

[0020] In one embodiment of the first aspect, the sheath forms an exoskeleton configured to provide structural support to the chamber.

[0021] In one embodiment of the first aspect, the storage tank further includes an isolation layer arranged to form a layer enclosing the exterior of the chamber.

[0022] In one embodiment of the first aspect, the sheet of at least the first set of support members is provided with openings.

[0023] In one embodiment of the first aspect, the sheet of the first set of support members includes metal.

[0024] In one embodiment of the first aspect, the metal is stainless steel.

[0025] In one embodiment of the first aspect, the sheet of the first set of support members includes plastic.

[0026] In one embodiment of the first aspect, the sheet of the first set of support members includes carbon fiber.

[0027] In one embodiment of the first aspect, the sheet of the first set of support members includes cellulose.

[0028] An advantage of the first aspect is at least an improved ability to conform to a desired external geometry. Another advantage is improved structural integrity.

[0029] The scope of the present invention is defined by the claims, which are incorporated by reference into this section. Reference will be made to the accompanying drawings, which will be briefly described first. Brief Description of the Drawings

[0030] Figure 1 A storage tank including a chamber is shown in accordance with one or more embodiments of the present disclosure.

[0031] Figure 2 A storage tank including a chamber and an inner skeleton is shown in accordance with one or more embodiments of the present disclosure.

[0032] Figure 3 An example of how one or more sheets of the first set of support members are attached to the side of the chamber facing the one or more sheets is shown.

[0033] Figure 4A The solution of the present disclosure is shown in comparison with a conventional solution.

[0034] Figure 4B Local stresses in the wall of the chamber for the present disclosure and in the wall of the chamber for the conventional solution are shown.

[0035] Figure 5A The inner skeleton is shown, where the storage tank includes only the first set of support members

[0036] Figure 5B shows an inner framework, wherein the storage tank includes a first set of support members and a second set of support members.

[0037] Figure 6 shows how the storage tank conforms to a desired external geometry.

[0038] Figure 7A -B shows a storage tank that further includes a sheath.

[0039] Figure 8 shows a storage tank that includes an isolation layer.

[0040] Figure 9 shows a storage tank according to one or more embodiments of the present disclosure, wherein the inner framework is coupled to the chamber by attaching one or more sheets of the first set of support members to the chamber.

[0041] Those skilled in the art will more fully understand the embodiments of the present invention and achieve their additional advantages by considering the following detailed description of one or more embodiments. It should be understood that the same reference numerals are used to identify the same elements shown in one or more figures. Detailed Description

[0042] The present disclosure is at least partially related to US10731344B2, the teachings of which are incorporated herein by reference in their entirety.

[0043] The present disclosure relates to storage tanks, particularly storage tanks that conform to a desired external geometry and can generally be accommodated in an available void of a mechanical structure. These storage tanks are intended for storing pressurized substances or substances stored at a pressure lower / higher than the ambient atmospheric pressure.

[0044] Challenges with such storage tanks include providing sufficient structural strength while considering weight limitations.

[0045] The present disclosure addresses these challenges by providing a chamber configured to enclose a pressurized substance and provide a seal between the pressurized substance and the surrounding atmosphere. Additionally, the storage tank includes an inner framework disposed within the chamber and coupled to the chamber to provide structural support to the chamber.

[0046] The inner framework includes a plurality of interconnected support members. The connection of the support members allows the inner framework to transfer forces between the plurality of interconnected support members.

[0047] This is the difference between the present disclosure and traditional solutions. Traditional solutions usually only strengthen the walls of the storage tank. In other words, traditional solutions mainly focus on avoiding the deformation of the walls of the storage tank. The present disclosure "fills" and / or "spans" the required external geometry with support elements, and couples the support members to each other and to the chamber to improve the structural integrity of the storage tank. In other words, the storage tank itself forms a support unit with relatively high structural integrity.

[0048] In addition, the plurality of coupled support members includes at least a first group of support members, and the at least first group of support members has sides formed by sheets. Compared with traditional solutions, these sheets can also be provided with openings to adapt to their load distribution.

[0049] Physical loads - forces, pressures, accelerations - are distributed in a physical structure in the form of material strains, and the material strains are in turn expressed as material stresses which are convenient quantification indices. Although it is generally desirable to obtain as smooth a stress field as possible to maximize material utilization as much as possible, this is only part of the equation. Strain is usually a more appropriate metric, and it can be used and manipulated in beneficial directions, which means adjusting the way the load is distributed by changing the geometry of the component or member.

[0050] Each support member in the first group of support members includes an internal asymmetric tetrahedral structure formed by its sides. In an embodiment, each side of the asymmetric tetrahedral structure formed by the sheet is in the shape of a non-equilateral triangle. This allows for the production of robust support members with adaptable external shapes and external dimensions.

[0051] In the present disclosure, the term "storage tank" refers to a receptacle or container configured to store solid, liquid, or gaseous substances.

[0052] In the present disclosure, the term "pressurized substance" refers to a substance stored at a lower / higher pressure than the surrounding atmosphere. These substances can be in solid, liquid, or gaseous states.

[0053] In the present disclosure, the term "chamber" refers to an airtight and / or liquid-tight membrane that encloses a pressurized substance and provides a seal between the pressurized substance and the surrounding atmosphere.

[0054] In the present disclosure, the term "endoskeleton" refers to a support structure arranged in the chamber of a storage tank in a manner similar to how an endoskeleton is arranged in the body of a living being.

[0055] In the present disclosure, the term "support member" refers to a mechanical element configured to transfer forces between at least two points.

[0056] In the present disclosure, the term "sheet" refers to a broad, flat piece of material or a broad extension or surface of something. An example of a sheet is a metal bar or strip made from a metal sheet. The metal bar or strip can also be manufactured by additive manufacturing or 3D printing.

[0057] In the present disclosure, the term "external dimension" refers to the volume formed by the contour of a support member.

[0058] In the present disclosure, the term "sheath" refers to the first layer enclosing the outside of a chamber.

[0059] Figure 1 Shown is a storage tank 100 including a chamber 110 according to one or more embodiments of the present disclosure. The storage tank 100 is configured to store a pressurized substance in any one of a solid, liquid, or gaseous state. In a non-limiting example, the substance is hydrogen. The storage tank 100 includes a chamber 110. The chamber is configured to enclose the pressurized substance and provide a seal between the pressurized substance and the surrounding atmosphere.

[0060] The chamber 110 of the storage tank 100 is configured to have a conformable shape, e.g., conforming to a desired external geometry intended to surround the chamber 110. This will be further described in Figure 3 below.

[0061] This is advantageous in the field of mechanical construction because by using a conformable storage tank, the voids in the mechanical construction can be fully utilized to store or hold the pressurized substance. Typically, such voids in a mechanical structure exist in the wings of an aircraft or in the chassis of a road vehicle. However, any other mechanical construction can benefit from the use of a conformable storage tank.

[0062] In traditional solutions, cylindrical, spherical, or box-shaped structures are often used. The disadvantage of such solutions is that the voids in the mechanical structure are not well utilized, or the structural integrity of such solutions is not very high.

[0063] Figure 2 Shown is a storage tank 100 including a chamber 110 and an inner skeleton 120 according to one or more embodiments of the present disclosure.

[0064] The inner skeleton 120 is disposed within the chamber 110 and is mechanically coupled to the chamber 110 to provide structural support to the chamber 110. By coupling the inner skeleton 120 to the chamber 110, the structural integrity of the storage tank is improved and the stress on the chamber walls is reduced.

[0065] The inner skeleton 120 is coupled to the chamber 110 by using suitable methods such as welding and / or bonding and / or brazing and / or melting and / or additive manufacturing and / or additive deposition.

[0066] The inner framework 120 includes a plurality of mechanically coupled support members 130. The support members 130 "fill" and / or "span" the interior of the chamber 110. The support members are mechanically coupled to each other and to the chamber 110 to increase the structural integrity of the storage tank. Connecting the support members 130 to each other improves the structural integrity of the storage tank, and since the connection of the support elements to each other and to the chamber 110 allows forces to be transferred between the support elements away from the chamber wall, the stress on the chamber wall is further reduced. In particular, adjacent support elements transfer forces between them.

[0067] The plurality of coupled support members 130 at least includes a first set of support members 131 having sides formed by sheets, wherein each support member of the first set 131 includes an internal asymmetric tetrahedral structure formed by its sides, and wherein each side of the asymmetric tetrahedral structure is in the shape of a non-equilateral triangle.

[0068] This has the advantage of creating relatively stronger support elements compared to using symmetric tetrahedral structures with sides in the shape of equilateral triangles, which can conform to any number of desired geometries.

[0069] For some storage tank geometries, the dimensions of the storage tank 100 are an integer multiple of the external dimensions of the support elements, and the support elements will completely fill or span the internal volume of the storage tank 100.

[0070] In one embodiment, each of the plurality of coupled support members 130 has equal external dimensions.

[0071] For other storage tank geometries, the dimensions of the storage tank 100 are not an integer multiple of the external dimensions of the support elements, and the support elements will need to have different external dimensions to completely or almost completely / fundamentally fill or span the internal volume of the storage tank 100.

[0072] In an alternative embodiment, at least some of the plurality of coupled support members 130 have different external dimensions.

[0073] Additionally, or alternatively, the inner framework 120 is coupled to the chamber 110 by attaching one or more sheets of the first set of support members 131 to the chamber 110. In one embodiment, at least some of the one or more sheets of the first set 131 are attached to the chamber 110 along the sides of the one or more sheets facing the chamber 110. In one example, the entire side of the one or more sheets facing the chamber 110 is welded to the chamber 110. In another example, the entire side of each of the one or more sheets facing the chamber 110 is folded to form a rectangular area, and the rectangular area is glued (adhered) to the chamber 110.

[0074] This has the advantage of reducing the stress in the wall of the chamber 110. This is achieved by effectively dividing the outer surface into smaller sub-surfaces, each of which bears a limited portion of the total load. Another advantage is that the internal skeleton unloads the wall of the chamber 110 and absorbs the load into the support members, which transfer the force into their structure. In other words, the internal skeleton supports the wall. Instead of the wall transferring the entire load via tangential stress, a portion of the load is transferred inward through the internal skeleton, which reduces the local stress in the wall.

[0075] In an embodiment, one or more sheets may be coupled / attached to the chamber 110 by welding and / or bonding and / or brazing and / or fusing and / or additive manufacturing and / or deposition.

[0076] In Figure 2 the support members are shown as having a similar orientation, but it should be understood that any suitable orientation may be used without departing from the present disclosure.

[0077] Figure 3 An example is shown of how one or more sheets of a first set of support members 131 are attached to the chamber 110 along a side of the one or more sheets facing the chamber 110.

[0078] In this example, the entire side of the one or more sheets facing the chamber 110 is welded to the chamber 110. In another example (not shown), each of the entire sides of the one or more sheets facing the chamber 110 is folded to form tabs or rectangular regions, and then the rectangular regions are attached, e.g., welded or bonded, to the wall of the chamber 110.

[0079] Figure 4A The solution of the present disclosure is shown in comparison with a conventional solution. As Figure 4A shown, the support elements of the present disclosure are attached along the entire side of one or more sheets facing the chamber 110.

[0080] In a conventional solution 420, support elements in the form of beams or trusses are typically attached to the chamber 110 at points at the ends of the beams or trusses. This has the disadvantage that the local stress at the points where the beams or trusses are attached to the wall of the chamber 110 is relatively high.

[0081] Figure 4B Local stresses in the wall 430 of the chamber for the present disclosure and in the wall 440 of the chamber for the conventional solution are shown. Figure 4B Images 430, 440 are shown, which indicate high local stress as darker regions and low local stress as lighter regions. As Figure 4B shown, compared with the conventional solution, the present solution reduces the local stress in the wall of the chamber. The high local stress in the wall of the chamber is shown as points in the right image 440.

[0082] Additionally, or alternatively, at least the sheets of the first set of support members 131 are provided with openings. By shaping the openings in different forms, the structural integrity characteristics of the support elements can be adapted to the required requirements.

[0083] Examples of the openings are shown in Figure 7A -B. The shape of the openings can be determined based on stress / strain analysis indicating a level below a threshold.

[0084] The sheets of the first set of support members 131 can include different suitable materials.

[0085] Additionally, or alternatively, the sheets of the first set of support members 131 include metal. In one embodiment, the metal is stainless steel.

[0086] Additionally, or alternatively, the sheets of the first set of support members 131 include plastic.

[0087] Additionally, or alternatively, the sheets of the first set of support members 131 include carbon fiber.

[0088] Additionally, or alternatively, the sheets of the first set of support members 131 include cellulose.

[0089] Figure 5A The inner skeleton 120 is shown, wherein the plurality of interconnected support members 130 includes only the first set of support members 131. For ease of reading, Figure 5A the chamber 110 is not shown.

[0090] Figure 5B The inner skeleton 120 is shown, wherein the plurality of interconnected support members 130 includes the first set of support members 131 and the second set of support members 132. Each support member in the second set 132 includes an internal polyhedral structure other than an asymmetric tetrahedral structure. In Figure 5B the example shown, a square tubular support element is shown. This is generally desirable in applications when the load or strain decreases towards the center of the storage tank.

[0091] Figure 6 It is shown how the storage tank 100 conforms to the required external geometry 300, for example, a void in a mechanical construction as described above. The present disclosure performs particularly well when the external geometry 300, such as a void in an aircraft wing, is irregular and asymmetric.

[0092] Figure 7A The storage tank 100 according to one or more embodiments of the present disclosure is shown further including a sheath 140. The sheath 140 is arranged to form a layer enclosing the exterior of the chamber 110.

[0093] In one embodiment, the sheath 140 forms an outer skeleton configured to provide structural support to the chamber 110. The sheath may also be attached to the chamber of the storage tank using suitable methods such as welding and / or bonding and / or brazing and / or melting and / or additive manufacturing and / or additive deposition. This is illustrated in the example shown in Figure 7A -B. Additionally, or alternatively, the sheath 140 is configured to provide thermal insulation and effectively form an insulating layer.

[0094] In some embodiments, a separate insulating layer is added to further protect the storage tank from the surrounding atmosphere.

[0095] Figure 7A An opening 160 in the sheet of the first set of support members 131 is further shown.

[0096] Figure 7B An exploded view of a storage tank 100 according to one or more embodiments of the present disclosure is shown.

[0097] Figure 8 A storage tank 100 including an insulating layer 150 is shown. In Figure 8 it, the external geometry 300 such as in an aircraft wing is irregular and asymmetric. The storage tank 100 includes a chamber 110 and an internal inner skeleton 120. The chamber 110 is also provided with an insulating layer 150.

[0098] In one embodiment, the storage tank further includes an insulating layer 150. The insulating layer 150 is arranged to form a layer surrounding the outside of the chamber 110.

[0099] Figure 9 A storage tank according to one or more embodiments of the present disclosure is shown, wherein the inner skeleton 120 is coupled to the chamber 110 by attaching one or more sheets of the first set of support members 131 to the chamber. One or more sheets of the first set 131 are attached to the chamber 110 along the sides 910 - 960 of the one or more sheets facing the chamber 110.

[0100] In other words, the sides (910 - 960) of the sheets of the first set of support members 131 facing the chamber 110 and / or the walls of the chamber 110 are attached to the walls of the chamber 110 along the sides 910 - 960 of the one or more sheets facing the chamber 110.

[0101] This has the advantage of also improving the structural integrity of the storage tank 100 when the dimensions of the chamber 110 are not an integer multiple of the dimensions of the support members. In other words, the ability to conform to voids in an irregular and asymmetric external geometry 300 such as in an aircraft wing is further improved.

[0102] In one embodiment, one or more sides (910 - 960) of the sheet of the first set of support members 131 are an integral part of the support members. In other words, the sides / sheet of the first set of support members 131 are generally conformable to and attached to the chamber wall.

[0103] In one embodiment, one or more sides (910 - 960) of the sheet of the first set of support members 131 are components that are added to and attached to the support members. In other words, additional components are added to the sides / sheet of the first set of support members 131, and the added components are attached to the inner and / or outer side of the chamber wall, for example, as Figure 7A and Figure 7B shown in, as part of the sheath 140.

[0104] Figure 9 An example is shown where additional components are added to the sides / sheet of the first set of support members 131, and the added components are attached to the interior of chamber 110 and / or the chamber wall.

[0105] It should be understood that even if not explicitly shown in the figures, the storage tank may be provided with additional features such as inlet / outlet connectors, sensors, or other auxiliary devices.

[0106] Finally, it should be understood that the present invention is not limited to the above embodiments, but also relates to and encompasses all embodiments within the scope of the appended independent claims.

Claims

1. A storage tank (100) configured to store a pressurized substance, the storage tank comprising: A chamber (110) configured to enclose the pressurized substance and provide a seal between the pressurized substance and the surrounding atmosphere, An internal framework (120) disposed within the chamber (110) and connected to the chamber (110) to provide structural support to the chamber (110), Wherein the internal framework (120) comprises a plurality of connected support members (130), wherein the plurality of connected support members (30) at least comprises a first group of support members (131), the first group of support members having sides formed by sheets, wherein each support member in the first group of support members (131) comprises an internal asymmetric tetrahedral structure formed by the sides, wherein each side of the asymmetric tetrahedral structure is in the shape of a non-equilateral triangle.

2. The storage tank according to claim 1, characterized in that, The chamber (110) is configured to have a shape conforming to a desired external geometry (300) intended to surround the chamber (110).

3. The storage tank according to any one of claims 1 or 2, characterized in that, The internal framework (120) further comprises a second group of support members (132), wherein each support member in the second group (132) comprises an internal polyhedral structure other than the asymmetric tetrahedral structure.

4. The storage tank according to any one of claims 1 to 3, characterized in that, Each of the plurality of connected support members (130) has an equal external dimension.

5. The storage tank according to any one of claims 1 to 3, characterized in that At least some of the plurality of connected support members (130) have different external dimensions.

6. The storage tank according to any one of the preceding claims, characterized in that, The internal framework (120) is connected to the chamber (110) by attaching one or more sheets of the first group of support members (131) to the chamber (110).

7. The storage tank according to claim 6, wherein, One or more sheets of the first group (131) are attached to the chamber (110) along sides (910 - 960) of the one or more sheets facing the chamber (110).

8. The storage tank according to claim 7, wherein, The one or more sheets are attached to the chamber (110) by welding and / or bonding and / or brazing and / or melting and / or additive manufacturing and / or deposition.

9. The storage tank according to any one of the preceding claims, characterized in that, Further comprising a sheath (140) disposed to form a layer enclosing the exterior of the chamber (110).

10. The storage tank according to claim 9, characterized in that, The sheath (140) forms an exoskeleton configured to provide structural support to the chamber (110).

11. The storage tank according to any one of the preceding claims, characterized in that, Further comprising an isolation layer (150) disposed to form a layer enclosing the exterior of the chamber (110).

12. The storage tank according to any one of the preceding claims, characterized in that, At least the sheets of the first group of support members (131) are provided with openings.

13. The storage tank according to any one of the preceding claims, characterized in that, The sheets of the first group of support members (131) comprise metal.

14. The storage tank according to claim 13, wherein, The metal is stainless steel.

15. The storage tank according to any one of the preceding claims, characterized in that, The sheets of the first group of support members (131) comprise plastic.

16. The storage tank according to any one of the preceding claims, characterized in that, The sheets of the first group of support members (131) comprise carbon fiber.

17. The storage tank according to any one of the preceding claims, characterized in that, The sheets of the first group of support members (131) comprise cellulose.

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