Manufacturing method for manufacturing a sealing membrane for a sealed insulated tank for storing liquefied gas

Abstract

A manufacturing method for manufacturing a sealing membrane for a sealed insulated tank for storing liquefied gas is described. A first metal sheet (144) and a second metal sheet (44) are arranged, and the second metal sheet (44) overlaps the first metal sheet (144) in an overlap zone (ZR). The first metal sheet (144) has a thickness increase portion (90) located in a straight line with at least a portion of the overlap zone (ZR) to thicken the first metal sheet (144) at at least joint portions (156a) between the corrugated portion (185a) of the first metal sheet (144) and two planar portions (186) of the first metal sheet (144). A continuous weld is created between the second metal sheet (44) and the first metal sheet (144) along the overlap zone (ZR), and the continuous weld extends in a straight line with the thickness increase portion (90).

Description

Technology Field

[0001] The present invention relates to the field of a closed-loop insulated tank having a membrane. In particular, the present invention relates to the field of a closed-loop insulated tank for storing and / or transporting liquefied gases, such as liquid hydrogen, at about -253°C at atmospheric pressure. Background Technology

[0002] In the prior art, a closed insulated tank for storing liquefied gases, such as liquefied natural gas (LNG) or liquid hydrogen, is known.

[0003] Document WO 2023 / 198637 A1 discloses a tank having walls having a multilayer structure, that is, a secondary insulation barrier fixed to a load-bearing structure in sequence, from the outside to the inside along the thickness direction of the walls, a secondary sealing membrane placed against the secondary insulation barrier, a primary insulation barrier placed against the secondary sealing membrane, and a primary sealing membrane intended to come into contact with the liquefied gas contained in the tank.

[0004] The primary insulation barrier includes rows of load-bearing elements, each of which is fastened to an outer plate and an inner plate, the outer plates are fastened to the secondary insulation barrier to press the secondary sealing membrane against the secondary insulation barrier, and the inner plates form a supporting surface for the primary sealing membrane.

[0005] The primary sealing membrane comprises a plurality of corrugated metal sheets, the edges of which are welded to the inner plates, and they are lap-welded along the edges to ensure fluid sealing of the primary sealing membrane.

[0006] These tanks are suitable for storing liquid hydrogen at -253°C at atmospheric pressure.

[0007] However, when the tank is filled with liquid hydrogen at -253°C at atmospheric pressure, the primary sealing membrane is exposed to very large thermal stress. Therefore, it is important to ensure the mechanical strength of the primary sealing membrane.

[0008] Meanwhile, to provide the required thermal insulation properties to the primary thermal insulation barrier, the primary thermal insulation barrier has a gaseous phase placed at a very low absolute pressure. It is important that this vacuum configuration is not compromised by the primary seal. The problem to be solved

[0009] Among the factors affecting the mechanical strength of the primary seal and the influence of the primary seal on the vacuum placement of the primary insulation barrier, there is the presence of residual pores within the welds between the corrugated metal sheets of the primary seal. If the welding operation causes excessive melting of the metal alloy of the corrugated metal sheets, there is a risk of significant residual pore formation in the welds between the corrugated metal sheets. This risk is further amplified if the welding operation is not performed in an inert atmosphere, as the metal alloy is more likely to be exposed to high-temperature oxidation due to high temperatures and the presence of atmospheric oxygen. The greater the number of residual pores in the welds between the corrugated metal sheets, the greater the surface irregularity becomes, increasing the likelihood of crack formation. This reduces the mechanical strength of the primary seal and increases the likelihood of degrading the vacuum performance of the primary insulation barrier. means of solving the problem

[0010] One of the ideas of the present invention is to propose a method for manufacturing sealing membranes that tend to limit residual pores within welds between corrugated metal sheets.

[0011] According to one embodiment, the present invention provides a method for manufacturing a sealing membrane for a tank wall for a sealed insulated tank for storing liquefied gas, said manufacturing method,

[0012] - A step of placing a first metal sheet and a second metal sheet on a flat support surface, wherein the first metal sheet and the second metal sheet each include two flat portions placed on the flat support surface and a corrugated portion formed between the two flat portions, and the corrugated portion protrudes with respect to the two flat portions.

[0013] The wrinkled portion of the first metal sheet and the wrinkled portion of the second metal sheet are aligned,

[0014] The second metal sheet overlaps the first metal sheet in an overlapping area defined between one edge of the first metal sheet and one edge of the second metal sheet parallel to the edge of the first metal sheet, and the corrugated portion of the first metal sheet extends to the edge of the first metal sheet and the corrugated portion of the second metal sheet extends to the edge of the second metal sheet, and

[0015] One end of the corrugated portion of the second metal sheet overlaps with one end of the corrugated portion of the first metal sheet in the overlap zone, the two planar portions of the second metal sheet overlap with the two planar portions of the first metal sheet in the overlap zone, and the first metal sheet is located between the second metal sheet and the support surface in the overlap zone.

[0016] A placement step in which the first metal sheet has a thickness increase portion located in a straight line with at least a portion of the overlapping area to thicken the first metal sheet at the joint portions between the corrugated portion of the first metal sheet and the two planar portions of the first metal sheet; and

[0017] - A step of creating a continuous weld between the second metal sheet and the first metal sheet along the overlapping area, wherein the continuous weld extends in a straight line with the thickness increase portion.

[0018] According to one embodiment, the present invention also provides a sealed insulated tank for storing liquefied gas, said tank comprising a tank wall including a flat support surface and a sealing membrane.

[0019] The above sealing membrane comprises a first metal sheet and a second metal sheet disposed on the planar support surface, wherein the first metal sheet and the second metal sheet each comprise two planar portions disposed on the planar support surface and a corrugated portion formed between the two planar portions, and the corrugated portion protrudes with respect to the two planar portions.

[0020] The wrinkled portion of the first metal sheet and the wrinkled portion of the second metal sheet are aligned,

[0021] The second metal sheet overlaps the first metal sheet in an overlapping area defined between one edge of the first metal sheet and one edge of the second metal sheet parallel to the edge of the first metal sheet, and the corrugated portion of the first metal sheet extends to the edge of the first metal sheet and the corrugated portion of the second metal sheet extends to the edge of the second metal sheet, and

[0022] One end of the corrugated portion of the second metal sheet overlaps with one end of the corrugated portion of the first metal sheet in the overlap zone, the two planar portions of the second metal sheet overlap with the two planar portions of the first metal sheet in the overlap zone, and the first metal sheet is located between the second metal sheet and the support surface in the overlap zone.

[0023] The first metal sheet has a thickness increase portion located in a straight line with at least a portion of the overlapping area to thicken the first metal sheet at the joint portions between the corrugated portion of the first metal sheet and the two planar portions of the first metal sheet.

[0024] The above sealing membrane includes a continuous weld between the second metal sheet and the first metal sheet along the overlapping area, and the continuous weld extends in a straight line with the thickness increase portion.

[0025] The presence of the thickness increase portion tends to prevent excessive melting of the metal alloy of the first metal sheet and high-temperature oxidation of the metal alloy of the first metal sheet, and thus tends to prevent the weld between the second metal sheet and the first metal sheet from having many residual pores after recrystallization of the metal alloy. Therefore, thanks to the thickness increase portion, the sealing membrane has improved mechanical strength and deteriorates less of the vacuum state of the insulating barrier beneath the sealing membrane.

[0026] In addition, the increased thickness portion tends to insulate the metal alloy of the first metal sheet from the atmosphere, so there is no need to perform continuous welding under an inert atmosphere for backing.

[0027] According to the embodiments, this manufacturing method or this tank may have one or more of the following features.

[0028] Various geometric structures can be considered for the thickness increase portion.

[0029] According to one embodiment, the thickness increase portion extends continuously from one of the two planar portions of the first metal sheet to the other of the two planar portions of the first metal sheet within the width of the corrugated portion of the first metal sheet.

[0030] According to one embodiment, the thickness increase portion has a constant thickness. In this way, the thickness increase portion can be manufactured inexpensively, for example, by press forming.

[0031] According to one embodiment, the thickness increase portion is thicker at the joint portions between the first metal sheet's corrugated portion and the two planar portions than at the crest portion of the corrugated portion.

[0032] Specifically, the risk of excessive melting of the metal alloy of the first metal sheet tends to be greater at the joints than at the floor portion, and therefore, it is desirable for the thickness increase portion to be thicker at the joints.

[0033] According to one embodiment, the thickness increase portion is attached to the two planar portions of the first metal sheet.

[0034] According to one embodiment, the thickness increase portion, the first metal sheet, and the second metal sheet are made of the same metal alloy. According to another embodiment, since the thickness increase portion contributes less to the mechanical strength of the sealing membrane, the thickness increase portion may be made of a metal alloy different from the metal alloy of the first metal sheet and the second metal sheet, particularly a cheaper metal alloy.

[0035] According to one embodiment, the second metal sheet includes a stepped portion along the edge of the second metal sheet.

[0036] According to one embodiment, the step of creating a continuous weld between the second metal sheet and the first metal sheet along the overlapping area is performed by an automatic welding machine, and the automatic welding machine moves parallel to the edges of the first metal sheet and the second metal sheet.

[0037] According to one embodiment, the step of creating the continuous weld between the second metal sheet and the first metal sheet along the overlapping area is not performed under an inert atmosphere for protection.

[0038] Specifically, since the increased thickness portion tends to insulate the weld between the second metal sheet and the first metal sheet from the atmosphere present on the back side of the sealing membrane, an inert atmosphere for protection is not required.

[0039] According to one embodiment, the step of placing the first metal sheet and the second metal sheet on the support surface includes the step of positioning the first metal sheet by inserting the thickness increase portion into the concave portion included in the support surface.

[0040] According to one embodiment, the support surface is the inner surface of the thermal insulation barrier.

[0041] According to one embodiment, the sealing membrane is a primary sealing membrane, the thermal insulation barrier is a primary thermal insulation barrier, and the tank wall further includes a secondary sealing membrane and a secondary thermal insulation barrier, wherein the secondary thermal insulation barrier is placed against a load-bearing wall, the secondary sealing membrane is placed against the secondary thermal insulation barrier, and the primary thermal insulation barrier is placed against the secondary sealing membrane.

[0042] According to one embodiment, the first insulation barrier comprises rows of load-bearing elements, each of which is fastened to an outer plate and an inner plate, the outer plates are fastened to the second insulation barrier and the second sealing membrane is pressed against the second insulation barrier, the inner plates form the support surface, and the step of placing the first metal sheet and the second metal sheet on the support surface includes the step of welding the first metal sheet and the second metal sheet to the inner plates.

[0043] According to another embodiment, the secondary insulation barrier comprises a plurality of secondary insulation blocks placed in parallel on the load-bearing wall, and the primary insulation barrier comprises a plurality of primary insulation blocks placed in parallel on the secondary insulation barrier and fixed to the secondary insulation barrier by fixing members supported by the secondary insulation blocks, and the primary insulation blocks comprise fixing plates, and the step of placing the first metal sheet and the second metal sheet on the support surface comprises the step of welding the first metal sheet and the second metal sheet to the fixing plates.

[0044] According to one embodiment, the present invention also provides a sealed insulating tank comprising a sealed membrane manufactured by a manufacturing method according to any one of the aforementioned embodiments.

[0045] The second metal sheet is welded to the first metal sheet along the overlapping area, and since the increased thickness portion is supported by the first metal sheet, the increased thickness portion always remains in the sealing membrane.

[0046] In one embodiment, the liquefied gas is liquid hydrogen.

[0047] These tanks may form part of onshore storage facilities or be installed on floating, coastal, or offshore structures, particularly on vessels for transporting liquid hydrogen, namely hydrogen tankers, Floating Storage and Regasification Units (FSRUs), Floating Production Storage and Offloading (FPSOs), etc. These tanks may also be used as fuel tanks on any type of vessel.

[0048] According to one embodiment, a vessel for transporting liquefied gas includes a double hull and the above-mentioned tank disposed within the double hull.

[0049] According to one embodiment, the present invention also provides a transport system for liquefied gas, the system comprising insulated pipes arranged to connect the said vessel and a tank installed within the hull of the vessel to a floating or onshore storage facility.

[0050] According to one embodiment, the transport system also includes a pump for allowing liquefied gas to flow through insulated pipes from a floating or land storage facility to a tank of a ship or from a tank of a ship to a floating or land storage facility.

[0051] According to one embodiment, the present invention also provides a method for loading or unloading such a vessel, wherein liquefied gas is transferred through insulated pipes from a floating or onshore storage facility to the tank of the vessel or from the tank of the vessel to a floating or onshore storage facility. Brief explanation of the drawing

[0052] The present invention will be better understood through the following description of some specific embodiments of the invention, which are made with reference to the accompanying drawings and provided only as non-limiting examples, and additional objects, details, features, and advantages thereof will become more apparent. Figure 1 is a partial perspective view of the tank wall of a closed insulated tank. FIG. 2 is a partial perspective view of a corrugated metal sheet having thickness-increasing portions. Figure 3 is a side view of the corrugated portion of the corrugated metal sheet of Figure 2 according to arrow A in Figure 2. FIG. 4 is a partial perspective view illustrating the arrangement of corrugated metal sheets of the primary insulation barrier of the tank wall of FIG. 1. Figure 5 is a partial cross-sectional perspective view of part V of Figure 4. FIG. 6 is a schematic cross-sectional view along a plane included in the overlapping area shown in FIG. 5. FIG. 7 is a partial schematic diagram of a ship tank and a terminal for loading / unloading from such tank. Specific details for implementing the invention

[0053] By convention, the terms "outer" and "inner" are used to define the location of different elements relative to the inside and outside of a tank.

[0054] FIG. 1 partially shows a perspective view of a tank wall (11) of a closed insulated tank for storing liquefied gas. The illustrated wall (11) is manufactured in accordance with the contents of document WO 2023 / 198637 A1.

[0055] As described in document WO 2023 / 198637 A1, the wall (11) is butted against a load-bearing wall that forms part of a load-bearing structure (1), for example, which is polyhedral. For example, the load-bearing structure (1) is formed by the double hull of a ship. The wall (11) has a multilayer structure comprising, in the thickness direction of the wall (11), from the outside to the inside, a secondary insulation barrier (12), a secondary sealing membrane (13), a primary insulation barrier (14), and a primary sealing membrane (15) intended to come into contact with the liquefied gas contained in the tank.

[0056] The secondary insulation barrier (12) comprises a plurality of insulation panels (16) fixed to a load-bearing structure (1). Each insulation panel (16) comprises an insulating polymer foam layer (17) sandwiched between an inner sheet (18) and an outer sheet (19). For example, the inner sheet (18) and the outer sheet (19) are plywood sheets bonded to the insulating polymer foam layer (17) with adhesive. According to one variation, the inner sheet (18) and the outer sheet (19) are made of a polymer matrix reinforced with fibers such as glass fibers. The insulating polymer foam may be, in particular, a polyurethane-based foam. The polymer foam is advantageously reinforced with fibers such as glass fibers that contribute to reducing thermal shrinkage.

[0057] Insulation panels (16) each comprise an insulating polymer foam layer (17) sandwiched between an inner sheet (18) and an outer sheet (19). For example, the inner sheet (18) and the outer sheet (19) are plywood sheets bonded to the insulating polymer foam layer (17) with adhesive. According to one variation, the inner sheet (18) and the outer sheet (19) are made of a polymer matrix reinforced with fibers such as glass fibers. The insulating polymer foam may be, in particular, a polyurethane-based foam. The polymer foam is advantageously reinforced with fibers such as glass fibers that contribute to reducing thermal shrinkage.

[0058] Advantageously, mastic portions (20) are interposed between the outer sheet (19) of the insulation panels (16) and the load-bearing structure (1). Thus, the mastic portions (20) contribute to compensating for surface irregularities of the load-bearing structure (1). According to an advantageous modified embodiment, the mastic portions (20) are bonded to the outer sheet (19) of the insulation panels (16) and the load-bearing structure (1). Thus, the mastic portions (20) help to secure the insulation panels (16) onto the load-bearing structure (1). In this modified embodiment, auxiliary fasteners are optional.

[0059] The insulation panels (16) are substantially rectangular in shape and are arranged in parallel rows spaced apart from each other by gaps (21) that ensure functional mounting spacing. The gaps (21) are filled with an insulating packing (not shown), such as, for example, glass wool, rock wool, or open-cell flexible polymer foam. For example, as described in application WO 2019155157 or WO 2021028624, the gaps may be filled with insulating plugs.

[0060] In the illustrated embodiment, the inner surface of the insulation panels (16) is formed on the corrugated metal sheets (25) of the secondary sealing membrane (13) and is intended to accommodate corrugations (24) protruding toward the outside of the tank, and represents two series of grooves (22) perpendicular to each other. Each of the groove (22) arrangements is parallel to two opposite sides of the insulation series (16). In the illustrated embodiment, the grooves (22) penetrate the entire thickness of the inner sheet (18) and enter the inner portion of the insulation polymer foam layer (17). Advantageously, the grooves (22) have a shape that complements the shape of the corrugations contained in the secondary sealing membrane (13).

[0061] Additionally, the insulation panels (16) have relaxation slits (27) that reduce stiffness, allowing the secondary insulation barrier (12) to deform as uniformly as possible. This allows for the most uniform deformation possible of the folds of the secondary sealing membrane (13). Advantageously, the insulation panels (16) have relaxation slits (27) directed toward at least each of the folds of the secondary sealing membrane (13). Further details regarding the insulation barrier (12) and the secondary sealing membrane (13) can be found in document WO 2023 / 198637 A1.

[0062] The primary insulation barrier (14) includes a plurality of load-bearing elements (30) extending in the thickness direction of the wall (11). The load-bearing elements (30) support the primary sealing membrane (15) and thus respond to loads resulting from hydrostatic pressure and dynamic pressure applied to the primary sealing membrane (15) by the liquefied gas contained inside the tank. The load-bearing elements (30) are arranged in parallel rows.

[0063] Further details regarding the load-bearing elements (30) can be found in document WO 2023 / 198637 A1. In particular, as described in this document, the load-bearing elements (30) are each fastened to the secondary insulation barrier (12) and fixed to the outer plate that presses the secondary sealing membrane (13) against the secondary insulation barrier (12), and are also fixed to the inner plate (42) (not shown in FIG. 1 but shown in FIG. 4).

[0064] The primary sealing membrane (15) is obtained by assembling a plurality of corrugated metal sheets (44). Each of the corrugated metal sheets (44) has a substantially rectangular shape. The corrugated metal sheets (44) are made of, for example, Invar®, that is, an alloy of iron and nickel with a coefficient of expansion typically between 1.2.10-6 and 2.10-6 K-1, or an iron alloy with a high manganese content with a coefficient of expansion typically around 7.10-6 K-1. Alternatively, the corrugated metal sheets (44) may be made of stainless steel or aluminum.

[0065] The corrugated metal sheets (44) are lap-welded along their edges to ensure fluid sealing of the primary sealing membrane (15). The primary sealing membrane (15) includes corrugations (45). More specifically, it includes a first corrugation continuum (45a) extending parallel to a first direction and a second corrugation continuum (45b) extending parallel to a second direction. The directions of the corrugation continuums (45a, 45b) are perpendicular to each other and are parallel or perpendicular to the rows of load-bearing elements (30). Each of the corrugation continuums (45a, 45b) is parallel to two opposite edges of the corrugated metal sheets (44). The corrugations (45) protrude toward the interior of the tank, that is, in a direction away from the load-bearing structure (1). Each corrugated metal sheet (44) includes a plurality of planar sections (46) between the corrugations (45). In this case, the folds (45b) have a smaller height than the folds (45a). In another embodiment, the folds (45a, 45b) may have the same height.

[0066] The pitch of the folds of the secondary sealing membrane (13) is equal to or an integer multiple of the pitch of the folds (45) of the primary sealing membrane (15). Additionally, each of the folds of the secondary sealing membrane (13) is positioned to face the folds (45) of the primary sealing membrane (15) in the thickness direction of the wall (11). Accordingly, each planar section (46) of the primary sealing membrane (15) is positioned to face the planar section of the secondary sealing membrane (13) in the thickness direction of the wall (11). Accordingly, the axis of each load-bearing member (30) passes through both the center of the planar section (46) of the primary sealing membrane (15) and the center of the planar section of the secondary sealing membrane (13).

[0067] The corrugated metal sheets (44) of the primary sealing membrane (15) are fixed to the inner plates (42) by welding along at least their edges. To this end, the edges of the corrugated metal sheets (44) are welded to the inner plates (42), for example, by spot welding. According to an advantageous embodiment, the corrugated metal sheets (44) are fixed to the inner plates (42) even outside their edge regions. To this end, the corrugated metal sheets (44) may be welded to the inner plates (42), particularly by transparent welding. According to an advantageous embodiment, the corrugated metal sheets (44) are welded to each of the inner plates (42) that support them. This embodiment is particularly advantageous in that it allows for a more uniform distribution of stress between the corrugations (45) of the primary sealing membrane (15).

[0068] Further details regarding the primary insulation barrier (14) can be found in document WO 2023 / 198637 A1. As described in this document, the wall (11) is suitable for constructing a sealed insulation tank for storing liquid hydrogen. Liquid hydrogen is a liquefied gas characterized by being stored at approximately -253°C at atmospheric pressure. When the tank is filled with liquid hydrogen at -253°C at atmospheric pressure, the primary sealing membrane (15) is subjected to very large thermal stress. Therefore, it is important to ensure the mechanical strength of the primary sealing membrane (15).

[0069] Additionally, as described in Document WO 2023 / 198637 A1, in order to provide the required thermal insulation properties to the primary thermal insulation barrier (14), the primary thermal insulation barrier (14) has a gas phase subjected to an absolute pressure of less than 1 Pa, advantageously less than 10⁻¹ Pa, preferably less than 10⁻² Pa, for example, about 10⁻³ Pa. This absolute pressure can be achieved by a vacuum pump and / or cryogenic pumping phenomena. Therefore, it is important that being subjected to such vacuum is not degraded by the primary sealing membrane (15).

[0070] As described above, the corrugated metal sheets (44) are overlap welded along their edges to ensure fluid sealing of the primary sealing membrane (15). During the welding process, the metal alloy constituting the corrugated metal sheets (44) is melted and then recrystallized. If the welding process causes excessive melting of the metal alloy, there is a risk that the welds between the corrugated metal sheets (44) will have a large number of residual pores after the recrystallization of the metal alloy. If the welding process is not performed in an inert atmosphere, this risk is further increased because the metal alloy is more likely to be exposed to high-temperature oxidation due to high temperatures and the presence of oxygen in the atmosphere. The more residual pores there are in the welds between the corrugated metal sheets (44), the greater the surface irregularity becomes, which increases the likelihood of cracking, which reduces the mechanical strength of the primary sealing membrane (15) and increases the likelihood of reducing the vacuum performance of the primary insulation barrier (14). Residual pores essentially increase the specific surface area of ​​the metal surfaces, which in turn increases the theoretical degassing rate calculated based on the underestimated nominal surface area. Vacuum performance may be degraded due to the creation of virtually sealed spaces, as these spaces become containers for gas and have high flow resistance at the outlet, making discharge via pumping more difficult. Therefore, it is particularly desirable to limit residual pores resulting from welding operations in the welds between the corrugated metal sheets (44).

[0071] Examples of a method for manufacturing a primary sealing membrane (15) that tends to limit such residual pores are described below. The manufacturing method uses a corrugated metal sheet (144) (hereinafter "sheet (144)") identical to the corrugated metal sheet (44) (hereinafter "sheet (44)"), except that it has thickness-increasing portions (90) as shown in FIGS. 2 to 6. Accordingly, the following description of the sheet (144) may also apply to the sheets (44), and elements of the sheet (144) identical to elements of the sheets (44) have the same reference numeral increased by 100.

[0072] In FIG. 2, where the sheet (144) is shown in a partial perspective view, it can be seen that the sheet (144) comprises flat portions (186) intended to be placed on the inner plates (42) and corrugated portions (185a, 185b) protruding from the flat portions (186). Each corrugated portion (185a, 185b) is formed between two flat portions (186). The corrugated portions (185a, 185b) are each intended to constitute part of the corrugations (45a, 45b) (see FIG. 1) of the primary sealing membrane (15). To this end, the corrugated portions (185b) have a lower height than the corrugated portions (185a) in this case. In another embodiment, the corrugated portions (185a, 185b) may have the same height.

[0073] Reference numeral 156a each indicates a joint between a flat portion (186) and a wrinkled portion (185a). Reference numerals 156b each indicate a joint between a flat portion (186) and a wrinkled portion (185b). Nodes (155) are formed at the intersections of the wrinkled portions (185a, 185b). To reduce the complexity of the drawings, the nodes (155) are omitted in FIGS. 1 and 4.

[0074] The sheet (144) has an outer contour that is generally rectangular and is defined by four mutually orthogonal straight edges (168). In FIG. 2, three of the four edges (168) are visible. As illustrated, the folded portions (185a, 185b) extend to the edges (168).

[0075] The sheet (144) has one thickness increase portion (90) for each wrinkle portion (185a). As illustrated in FIG. 2, the edges of the thickness increase portions (90) are preferably aligned with the edge (168) to which the wrinkle portions (185a) extend, or are spaced less than 5 mm away from the edge (168). In the drawings, the thickness increase portion (90) is depicted as a monolithic part. However, other implementations are possible, such as the thickness increase portion comprising multiple parts, for example, two sheets of small thickness. According to a non-limiting embodiment, the thickness increase portion (90) comprises a first small part having a thickness of 2 mm at the valley of the wrinkle and a second small part having a thickness of 1.5 mm at the crest of the wrinkle.

[0076] FIG. 3 is a side view of one of the corrugated portions (185a) according to arrow A in FIG. 2. As can be seen more clearly in FIG. 3, thickness increase portions (90) are arranged to thicken the sheet (144) in parts of the corrugated portions (185a), joints (156a), and flat portions (186) near the joints (156a).

[0077] Referring again to FIG. 2, the sheet (144) has a step along at least one of the other edges (168), and the sheet (144) includes a step portion (joggle, joggling) or a step bend (joggle bend) (167) along the edge (168). Preferably, as better shown in FIG. 4, each sheet (144) has a step along two vertical edges (168) corresponding to the step portion (167) and the step portion (67), respectively. (In this case, the step portion (67) is shown on another rectangular sheet (44).) Preferably, the thickness increase portions are placed along two edges (168) that do not have a step portion, for example, along two edges (168) that do not have a step portion (167, 67), in folds near one or more edges (168) of the sheet (144) that do not have a step portion.

[0078] In the first step of the manufacturing method, a sheet (144) and a sheet (44) are placed. This first step is illustrated by FIG. 4 and FIG. 5, which is a partial cross-sectional perspective view of the V portion of FIG. 4. In FIG. 5, to reduce the complexity of the drawing, the inner plates (42) are omitted and only the sheet (144) and the sheet (44) are shown.

[0079] As illustrated in FIG. 4, recesses (429) are provided in the inner plates (42) to accommodate the thickness increase portions (90). Also, in FIG. 4, it can be seen that the inner plates (42) include through holes (423). These through holes (423) are intended to accommodate rivets distributed around the axis of the load-bearing element (30) to fasten the load-bearing element (30) to the inner plates (42), as described in Document WO 2023 / 198637 A1.

[0080] The sheet (144) is positioned by inserting the thickness increase portions (90) into the concave portions (429).

[0081] When the sheet (144) is positioned in this manner, the sheet (44) is positioned, and its stepped portion (67) overlaps the sheet (144) in the overlap zone (ZR). Referring to FIG. 5, the overlap zone (ZR) is defined between the edge (168) of the sheet (144) and the edge (68) of the sheet (44) parallel to the edge (168). The dashed lines in FIG. 5 indicate the location of the overlap zone (ZR). As shown in FIG. 5, the corrugated portion (185a) of the sheet (144) and the corrugated portion (85a) of the sheet (44) are aligned, the end of the corrugated portion (85a) overlaps the end of the corrugated portion (185a) in the overlap zone (ZR), and the flat portions (86) on both sides of the corrugated portion (85a) overlap the flat portions (186) on both sides of the corrugated portion (185a) in the overlap zone (ZR). One of the flat sections (86) can be seen in FIG. 5, and the sheet (44) is cut along the folded section (85a) to indicate the thickness increase section (90). The thickness increase section (90) is located in line with at least a portion of the overlapping zone (ZR).

[0082] It should be understood that when the sheet (44) and the sheet (144) are positioned in this manner, their flat portions (86, 186) are placed on the inner plates (42) (see FIG. 4). These inner plates (42) form a supporting surface for the sheet (44) and the sheet (144), and thus form a supporting surface for the primary sealing membrane (15). Before proceeding to the second step, the sheet (44) and the sheet (144) are fixed to the inner plates (42) by welding along their edges (68, 168) as described above. For example, the sheet (144) is welded to the inner plates (42) before the sheet (44) is positioned to overlap with the sheet (144) in the overlap zone (ZR).

[0083] In the second step of the manufacturing method, a continuous weld is created between the sheet (44) and the sheet (144) along the overlap zone (ZR), and this continuous weld extends in a straight line with the thickness increase portion (90). The second step is illustrated in FIG. 6. The continuous weld is created according to a known welding technique using a welding torch. For example, the welding torch is mounted on an automatic welding machine that moves parallel to the edges (68, 168) defining the overlap zone (ZR). The arrow W in FIG. 5 indicates the forward direction of the automatic welding machine. The automatic welding machine can be manufactured, for example, as described in document EP 0 611 217 A1. Thus, at the end of the second step, the sheet (44) is overlap welded to the sheet (144) along the overlap zone (ZR).

[0084] The steps of the manufacturing method described above are repeated as many times as necessary until the manufacturing of the primary sealing membrane (15) is completed.

[0085] It should be noted that since the sheet (44) is overlap welded to the sheet (144) along the overlap zone (ZR) and the thickness increase portion (90) is supported by the sheet (144), the thickness increase portion (90) always remains in the primary sealing membrane (15) at the end of the manufacturing method.

[0086] Although not illustrated in FIG. 4, the present invention also applies to cases where an inner plate (42) is connected to another inner plate (42) adjacent thereto by a connection having a translational degree of freedom in a direction perpendicular to the thickness direction of the wall and a connection degree of freedom in the thickness direction of the wall. This allows the inner plates to be connected to the planar portions (186) of the sealing membrane to perform relative movement in a direction perpendicular to the thickness direction of the wall.

[0087] On the other hand, it should be noted that as an alternative or additional example to the wrinkle portions (185a), the sheet (144) may have a thickness increase portion similar to the thickness increase portion (90) of the wrinkle portions (185b). As previously described, the sheet (44) is overlap welded to the sheet (144) in a straight line with this thickness increase portion. In other words, the sheet (144) may have a thickness increase portion in the large wrinkles and / or small wrinkles.

[0088] FIG. 6 is a schematic diagram of the sheet (44) and sheet (144) illustrated in FIG. 5, showing a cross-section along a plane parallel to the forward movement direction (W) contained within the overlapping zone (ZR). It is noted that the sheets (44, 144) and the thickness increase portion (90) are schematically drawn with lines to facilitate the following description.

[0089] FIG. 6 shows three consecutive positions of the welding torch (900) during the second step of the manufacturing method in dashed lines. As shown in FIG. 6, the welding torch (900) may be equipped with a rotational function to follow the outer contours of the corrugated portions (85a, 185a). The welding torch (900) may be mounted on an automatic welding machine as described above. Due to the presence of the thickness increase portion (90), the sheet (144) has increased thermal inertia in the corrugated portion (185a), the joints (156a), and parts of the flat portions (186) near the joints (156a). Additionally, the thickness increase portion (90) tends to insulate the weld between the sheet (44) and the sheet (144) from the atmosphere. The presence of the thickness increase portion (90) tends to prevent excessive melting of the metal alloy of the sheet (144) and high-temperature oxidation of the metal alloy of the sheet (144), and thus tends to prevent the weld between the sheet (44) and the sheet (144) from having many residual pores after recrystallization of the metal alloy. Thus, thanks to the thickness increase portion (90), the primary sealing membrane (15) has improved mechanical strength and degrades the vacuum state of the primary insulation barrier (14) less. In addition, the thickness increase portion (90) tends to insulate the metal alloy of the sheet (144) from the atmosphere, so there is no need to perform continuous welding under an inert atmosphere as a precaution.

[0090] According to one variation, the thickness increase portion (90) is made of the same metal alloy as the sheets (44, 144). According to another variation, the thickness increase portion (90) may be made of a different metal alloy from the metal alloy of the sheets (44, 144), particularly a cheaper and metallurgically compatible metal alloy (i.e., an alloy that can be welded without difficulty and without producing galvanic corrosion), because the thickness increase portion (90) contributes less to the mechanical strength of the primary sealing membrane (15).

[0091] In the embodiments illustrated in FIGS. 2 to 6, the thickness increase portion (90) extends continuously within the width of the corrugated portion (185a) between the two flat portions (186) on both sides of the corrugated portion (185a) and has a constant thickness. In this way, the thickness increase portion (90) can be manufactured inexpensively, for example, by press forming.

[0092] In one variation, the thickness increase portion (90) may have different geometric structures.

[0093] In particular, according to one variant, the thickness increase portion (90) is thicker at the joint (156a) than at the crest portion (185at) of the corrugated portion (185a) (see FIG. 3). Specifically, because of the rotation of the welding torch (900) to follow the outer contour of the corrugated portions (85a, 185a), the risk of excessive melting of the metal alloy of the sheet (144) tends to be greater at the joint (156a) than at the crest portion (185at), and therefore, in order to obtain increased thermal inertia at the joint (156a), it is desirable for the thickness increase portion (90) to be thicker at the joint (156a).

[0094] For this reason, according to another variation, it may be considered that the thickness increase portion (90) is positioned to thicken the sheet (144) only at the joints (156a). In other words, according to this variation, the sheet (144) has a thickness increase portion (90) at each joint (156a), and these thickness increase portions (90) extend only within the width of the fold portion (185a) to the other joint (156a) corresponding to the fold portion.

[0095] In the aforementioned variations, the thickness increase portions (90) are preferably attached to the sheet (144) to facilitate the manufacture of the sheet (144). For example, the thickness increase portions (90) are attached to the sheet (144) by spot welding. More preferably, the thickness increase portions (90) are attached by spot welding to both the flat portions (186) and the corrugated portions (185a and / or 185b) of the sheet (144). Thus, the thickness increase portions (90) are attached sufficiently so that they can be held together without separating when handling the sheets.

[0096] The manufacturing method was described in the context of a closed-insulated tank for storing liquid hydrogen. In one variation, the closed-insulated tank may also be used to store other liquid gases, particularly liquefied natural gas (LNG), liquefied petroleum gas (LPG), ethane, or ammonia.

[0097] The manufacturing method has been described in the context of a tank wall manufactured in accordance with the contents of Document WO 2023 / 198637 A1. However, the manufacturing method is also applicable to any other tank wall in which a sealing membrane is manufactured by the overlapping welding of corrugated metal sheets, in particular a tank wall in which a secondary insulation barrier comprises a plurality of secondary insulation blocks juxtaposed on a load-bearing wall, and a primary insulation barrier comprises a plurality of primary insulation blocks juxtaposed on a secondary sealing membrane and fixed to the secondary insulation barrier by fixing members supported by the secondary insulation blocks, and the primary insulation blocks comprise fixing plates. Such a tank wall may be manufactured, for example, in accordance with the contents of Document FR 2 691 520 A1, Document WO 2014 / 057221 A2, or Document WO 2017 / 006044 A1. The edges of the sheets (44, 144) are fixed to the fixing plates rather than to the inner plates (42) mentioned above.

[0098] Referring to FIG. 7, a partial cutaway of a vessel (70) illustrates a generally prismatic sealed insulated tank (71) mounted within the double hull (72) of the vessel. The tank walls include a primary sealing membrane intended to come into contact with a liquefied gas, preferably liquid hydrogen, contained within the tank, a secondary sealing membrane positioned between the primary sealing membrane and the double hull (72) of the vessel, and two insulating barriers positioned between the primary sealing membrane and the secondary sealing membrane and between the secondary sealing membrane and the double hull (72), respectively.

[0099] As is known by itself, the loading / unloading pipes (73) placed on the upper deck of the ship can be connected to a sea or port terminal by a suitable connector to transport liquefied gas cargo from or to the tank (71).

[0100] FIG. 7 also illustrates an example of a marine terminal including a loading and unloading station (75), an underwater line (76), and a land facility (77). The loading and unloading station (75) is a fixed marine facility including a movable arm (74) and a tower (78) supporting the movable arm (74). The movable arm (74) carries a bundle of flexible insulated hoses (79) that can be connected to loading / unloading pipes (73). The oriented movable arm (74) is suitable for hydrogen carriers of all sizes. A connecting line (not shown) extends inside the tower (78). The loading and unloading station (75) enables loading from the land facility (77) to the hydrogen carrier (70) or unloading from the hydrogen carrier (70) to the land facility (77). These facilities include a liquefied gas storage tank (80) and a connecting line (81) that connects to a loading or unloading station (75) via an underwater line (76). The underwater line (76) enables the liquefied gas to be transported over a long distance, e.g., 5 km, between the loading or unloading station (75) and the land facility (77), allowing the hydrogen carrier (70) to be anchored away from the shore during loading and unloading operations.

[0101] To generate the pressure required to transport the liquefied gas, a pump mounted on the vessel (70) and / or a pump mounted on the land facility (77) and / or a pump mounted on the loading and unloading station (75) may be used, and the pressure within the internal space of the tank may be increased by the effect of the evaporation of the liquefied gas stored in the tank.

[0102] Although the present invention has been described in relation to several specific embodiments, it is not limited thereto and is evident that it includes all technical equivalents of the described means and combinations thereof if they fall within the scope of the invention.

[0103] The use of the verbs "to have," "to equip," or "to include" and their conjugations does not exclude the existence of other elements or steps other than those specified in the claim.

[0104] In the scope of the claims, reference numerals in parentheses should not be interpreted as limiting the claims. Explanation of the symbols

[0105] 1. Load-bearing structure 11 tank wall 12 Secondary insulation barrier 13 Secondary seal 14 Primary insulation barrier 15 Primary seal 16 insulation panels 17 Insulating polymer foam layer 18 inner seat 19 outer sheet 20 mastic parts 21 intervals 22 Home 24 Wrinkles (of the secondary sealing membrane) 25 Corrugated metal sheet (of the secondary sealing membrane) 27 Relaxation slit 30 load-bearing elements 42 inner plate 44 Corrugated metal sheet (of the primary sealing membrane) 45 Wrinkles (of the primary seal) 45a First fold arrangement 45b Second fold arrangement 46 Planar Zones 67 Step section 70 ships 71 Sealed insulated tank 72 double hull 73 Loading / Unloading Pipe 74 Mobile arm 75 Loading and Unloading Stations 76 Underwater Line 77 Athletic Facilities 78 Tower 79 Flexible Insulated Hose 80 liquefied gas storage tanks 81 connection line 90 parts with increased thickness 144 corrugated metal sheet 155 nodes 156a joint 156b joint 167 Step section 168 edge 185a folded part 185b wrinkled part 185at floor section 186 Planar section 423 Through hole 429 Concave part 900 welding torch ZR overlapping zone

Claims

Claim 1 A manufacturing method for manufacturing a sealing membrane for a tank wall for a sealed insulated tank for storing liquefied gas, wherein the manufacturing method comprises: a step of placing a first metal sheet (144) and a second metal sheet (44) on a flat support surface, wherein the first metal sheet (144) and the second metal sheet (44) each comprise two flat portions (186, 86) placed on the flat support surface and a corrugated portion (185a, 85a) formed between the two flat portions (186, 86), wherein the corrugated portion (185a, 85a) protrudes relative to the two flat portions (186, 86), wherein the corrugated portion (185a) of the first metal sheet (144) and the corrugated portion (85a) of the second metal sheet (44) are aligned, and wherein the second metal sheet (44) has one edge (168) of the first metal sheet (144) and the The first metal sheet (144) is overlapped in an overlap zone (ZR) defined between one edge (68) of the second metal sheet (44) parallel to the edge (168) of the first metal sheet (144), the wrinkled portion (185a) of the first metal sheet (144) extends to the edge (168) of the first metal sheet (144), the wrinkled portion (85a) of the second metal sheet (44) extends to the edge (68) of the second metal sheet (44), one end of the wrinkled portion (85a) of the second metal sheet (44) overlaps with one end of the wrinkled portion (185a) of the first metal sheet (144) in the overlap zone (ZR), and the two planar portions (86) of the second metal sheet (44) are the first metal sheet (144) in the overlap zone (ZR). Overlapping two planar portions (186), the first metal sheet (144) is positioned between the second metal sheet (44) and the support surface in the overlap area (ZR), and the first metal sheet (144) is,A manufacturing method comprising: a placement step having a thickness increase portion (90) located in a straight line with at least a portion of the overlap zone (ZR) to thicken the first metal sheet (144) at at least joint portions (156a) between the corrugated portion (185a) of the first metal sheet (144) and the two planar portions (186) of the first metal sheet (144); and a creation step of creating a continuous weld between the second metal sheet (44) and the first metal sheet (144) along the overlap zone (ZR), wherein the continuous weld extends in a straight line with the thickness increase portion (90). Claim 2 A method of manufacturing in which, in claim 1, the thickness increase portion (90) extends continuously from one of the two planar portions (186) of the first metal sheet (144) to the other of the two planar portions (186) of the first metal sheet (144) within the width of the corrugated portion (185a) of the first metal sheet (144). Claim 3 In paragraph 2, the manufacturing method wherein the thickness increase portion (90) is thicker at the joint portion (156a) between the corrugated portion (185a) of the first metal sheet (144) and the two flat portions (186) than at the crest portion (185at) of the corrugated portion (185a). Claim 4 A method of manufacturing in any one of claims 1 to 3, wherein the thickness increase portion (90) is attached to the two planar portions (186) of the first metal sheet (144). Claim 5 A manufacturing method according to any one of claims 1 to 4, wherein the thickness increase portion (90), the first metal sheet (144), and the second metal sheet (44) are made of the same metal alloy. Claim 6 A manufacturing method according to any one of claims 1 to 5, wherein the second metal sheet (44) comprises a stepped portion (67) along the edge (68) of the second metal sheet (44). Claim 7 A manufacturing method according to any one of claims 1 to 6, wherein the step of creating a continuous weld between the second metal sheet (44) and the first metal sheet (144) along the overlapping zone (ZR) is performed by an automatic welding machine, and the automatic welding machine moves parallel to the edges (168, 68) of the first metal sheet (144) and the second metal sheet (44). Claim 8 A manufacturing method according to any one of claims 1 to 7, wherein the step of placing the first metal sheet (144) and the second metal sheet (44) on the support surface comprises the step of positioning the first metal sheet (144) by inserting the thickness increase portion (90) into the concave portion (429) included in the support surface. Claim 9 A manufacturing method according to any one of claims 1 to 8, wherein the supporting surface is the inner surface of the thermal insulation barrier. Claim 10 In claim 9, the sealing membrane is a primary sealing membrane (15), the insulation barrier is a primary insulation barrier (14), and the tank wall (11) further comprises a secondary sealing membrane (13) and a secondary insulation barrier (12), the secondary insulation barrier (12) is placed against a load-bearing wall, the secondary sealing membrane (13) is placed against the secondary insulation barrier (12), the primary insulation barrier (14) is placed against the secondary sealing membrane (13), the primary insulation barrier (14) comprises rows of load-bearing elements (30), each of the load-bearing elements is fastened to an outer plate and an inner plate (42), the outer plates are fastened to the secondary insulation barrier (12) and press the secondary sealing membrane (13) against the secondary insulation barrier (12), and the inner plates (42) are the supporting surface A manufacturing method comprising the step of forming and placing the first metal sheet (44) and the second metal sheet (44) on the support surface, and welding the first metal sheet (44) and the second metal sheet (44) to the inner plates (42). Claim 11 A sealed insulated tank for storing liquefied gas, wherein the tank comprises a tank wall including a flat support surface and a sealing membrane, wherein the sealing membrane comprises a first metal sheet (144) and a second metal sheet (44) disposed on the flat support surface, wherein the first metal sheet (144) and the second metal sheet (44) each comprise two flat portions (186, 86) disposed on the flat support surface and a corrugated portion (185a, 85a) formed between the two flat portions (186, 86), wherein the corrugated portion (185a, 85a) protrudes relative to the two flat portions (186, 86), wherein the corrugated portion (185a) of the first metal sheet (144) and the corrugated portion (85a) of the second metal sheet (44) are aligned, and the second metal sheet (44) has one edge (168) of the first metal sheet (144) and The first metal sheet (144) is superimposed on the first metal sheet (144) in an overlapping zone (ZR) defined between one edge (68) of the second metal sheet (44) parallel to the edge (168) of the first metal sheet (144), the corrugated portion (185a) of the first metal sheet (144) extends to the edge (168) of the first metal sheet (144), and the corrugated portion (85a) of the second metal sheet (44) extends to the edge (68) of the second metal sheet (44), and one end of the corrugated portion (85a) of the second metal sheet (44) is superimposed on one end of the corrugated portion (185a) of the first metal sheet (144) in the overlapping zone (ZR), and the two planar portions (86) of the second metal sheet (44) are of the first metal sheet (144) in the overlapping zone (ZR). The first metal sheet (144) is positioned between the second metal sheet (44) and the support surface in the overlapping area (ZR), and the first metal sheet (144) is superimposed on the two planar portions (186), and the first metal sheet (144) is,A tank having a thickness increase portion (90) located in a straight line with at least a portion of the overlap zone (ZR) to thicken the first metal sheet (144) at the joint portions (156a) between the two planar portions (186) of the first metal sheet (144), the sealing membrane having a continuous weld between the second metal sheet (44) and the first metal sheet (144) along the overlap zone (ZR), the continuous weld extending in a straight line with the thickness increase portion (90). Claim 12 A vessel (70) for transporting liquefied gas, comprising a double hull (72) and a tank (71) according to claim 11 disposed within the double hull. Claim 13 A transport system for liquefied gas, comprising: a vessel (70) according to claim 12; insulating pipes (73, 79, 76, 81) arranged to connect the tank (71) installed within the hull of the vessel to a floating or land storage facility (77); and a pump that causes the liquefied gas to flow through the insulating pipes from the floating or land storage facility to the tank of the vessel or from the tank of the vessel to the floating or land storage facility. Claim 14 A method for loading or unloading a vessel (70) according to paragraph 12, wherein liquefied gas is transferred through insulating pipes (73, 79, 76, 81) from a floating or land storage facility (77) to the tank (71) of the vessel (70) or from the tank (71) of the vessel (70) to the floating or land storage facility (77).

Images