Watertight and thermally insulated tank

Abstract

The invention relates to a watertight and thermally insulating tank, comprising a watertight membrane (10) having a plurality of strakes (11) having at least one longitudinal corrugation (13) projecting towards the interior of the tank, wherein said or each corrugation (13) comprises: - two concave curved portions (131) connected to an element (125A, 125B) of the flat portion (12) of the strake (11, 11'), - a central flat portion (132) at the apex of the corrugation (13, 13'), and - two convex curved portions (133) each connecting one end of the central flat portion (132) to said concave curved portion (131). Figure for the abstract: 3

Description

Title of the invention: Watertight and thermally insulating tank technical field

[0001] The invention relates to the field of leak-proof and thermally insulated membrane tanks. In particular, the invention relates to the field of leak-proof and thermally insulated tanks for the storage and / or transport of low-temperature liquids, such as tanks for transporting Liquefied Natural Gas (LNG) at approximately -162°C at atmospheric pressure, ammonia (NH3) at -30°C at atmospheric pressure, or Liquefied Petroleum Gas (also called LPG) with a temperature, for example, between -50°C and 0°C. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank can be used for transporting liquefied gas or for receiving liquefied gas to serve as fuel for the propulsion of the floating structure. In the case of an onshore tank or a port storage structure, it can rest on the ground or the seabed and can be partially or completely buried. Technological background

[0002] For example, a watertight and thermally insulating tank integrated into a load-bearing structure is known from document WO2021074435. The tank comprises a first tank wall fixed to a first load-bearing wall and a second tank wall fixed to a second load-bearing wall joining the first load-bearing wall at an edge of the load-bearing structure. Each of the first and second tank walls comprises at least one watertight membrane and an insulating barrier arranged between the watertight membrane and the load-bearing wall. The watertight membrane comprises a plurality of flanges made of a low-expansion alloy. Each flange has a flat central portion resting on an upper surface of the insulating barrier and two raised edges projecting inward from the central portion of the tank. The flanges are juxtaposed and welded together watertight at the raised edges.

[0003] The tank wall further comprises a metal corner beam arranged parallel to the edge and anchored to the first and second load-bearing walls, the corner beam comprising a first flat flange parallel to the first load-bearing wall and a second flat flange parallel to the second load-bearing wall, the two flat flanges being rigidly connected to each other at a watertight connection zone forming an angle of the watertight membrane, each of the first and second flat flanges having a receiving strip extending at a distance from the edge from the zone of connection. In this tank, a portion of the end of the strakes of the watertight membrane is welded to a distal portion of the receiving strips Summary of the invention

[0004] One idea underlying the invention is to provide a sealed and thermally insulating tank in which the sealed membrane can be manufactured with a high level of reliability and longevity.

[0005] According to one embodiment, the invention provides a watertight and thermally insulating tank, integrated into a load-bearing structure comprising a load-bearing wall, the tank comprising a tank wall fixed to the load-bearing wall, in which the tank wall comprises at least one watertight membrane and an insulating barrier arranged between the watertight membrane and the load-bearing wall, in which the watertight membrane comprises a plurality of parallel strakes, a strake being in the form of a metal strip elongated in a longitudinal direction and having a uniform profile along the longitudinal direction, each strake comprising a flat portion resting on an internal surface of the insulating barrier and at least one longitudinal corrugation projecting into the interior of the tank relative to the flat portion of the strake, said or each longitudinal corrugation being spaced from the longitudinal edges of the strake,each longitudinal corrugation extending along the longitudinal direction of the strake, the strakes being juxtaposed and welded together in a watertight manner at said longitudinal edges, in which said or each corrugation or all of the corrugations or certain corrugations or the corrugations comprise: , - two concave curved sections connected to an element of the flat portion of the strake, - a central flat section located at the apex of the corrugation and - two convex curved parts, each connecting one end of the central flat part to a said concave curved part of the undulation.

[0006] Thanks to the specific shape of the corrugations described above, the membrane's flexibility is improved. The membrane's resistance to the mechanical and thermal stresses experienced during its use in the tank wall is increased. This results in a particularly robust tank.

[0007] Thanks to this improved flexibility, the waterproof membrane can be made of a less expensive material with a higher coefficient of thermal expansion while preserving the resistance to mechanical and thermal stresses of the tank, even if it is subjected to greater stresses.

[0008] In addition, thanks to the undulations described above, it is possible to use strakes that do not have longitudinal edges raised towards the inside of the tank.

[0009] It is also possible to consider using a strake having at least one corrugation and raised edges. Such a strake may, for example, have a width equal to the width of one or two insulating blocks of the corresponding insulating barrier.

[0010] According to embodiments, such a tank may include one or more of the following characteristics.

[0011] According to one embodiment, one or each or all or some or the concave curved part of said or each undulation is directly connected to one of the two convex curved parts of the undulation.

[0012] According to one embodiment, one or each or all or some or the concave curved part of said or each undulation is connected to one of the two convex curved parts of the undulation by a lateral planar part of the undulation.

[0013] According to one embodiment, one or each or all or some or the concave curved part and / or one or each or all or some or the convex curved part of said or each undulation presents, along a plane perpendicular to said longitudinal direction, a circular arc section whose radius of curvature is between 5 and 15 millimeters.

[0014] According to one embodiment, the circular arc section extends over an angle between 10 and 80 degrees of arc.

[0015] According to one embodiment, the flat parts and the concave curved parts or the convex curved parts of said or each undulation extend into one another in such a way that the profile of said or each undulation has a slope varying continuously in a plane perpendicular to the longitudinal direction.

[0016] According to one embodiment, the central flat part, the lateral flat parts and the concave curved parts or the convex curved parts of said or each undulation extend one another in such a way that the profile of said or each undulation has a slope varying continuously in a plane perpendicular to the longitudinal direction.

[0017] According to one embodiment, said corrugation or each corrugation extends laterally, in a direction perpendicular to the longitudinal direction, over a total width measured from one concave curved portion to the other of between 30 and 70 millimeters. The direction perpendicular to the longitudinal direction is also parallel to the flat portion of the strake.

[0018] According to one embodiment, said or each corrugation extends vertically along a thickness direction of the tank, over a total height measured between the flat portion of the strake and the central flat part of the corrugation of between 8 and 17 millimeters.

[0019] According to one embodiment, the central flat part of said or each undulation extends laterally, in the direction perpendicular to the longitudinal direction, over a width of between 4 and 30 millimeters.

[0020] According to one embodiment: - said load-bearing wall is a first load-bearing wall and the load-bearing structure further comprises a second load-bearing wall, joining the first load-bearing wall at an edge of the load-bearing structure, - said tank wall is a first tank wall and the tank comprises a second tank wall fixed to the second load-bearing wall, - the tank includes a metal corner beam arranged parallel to the edge of the supporting structure and anchored to the first and second supporting walls, the corner beam having a first lateral wing parallel to the first supporting wall and a second lateral wing parallel to the second supporting wall, the two lateral wings being linked to each other at the level of a watertight connection zone, the first lateral wing of the corner beam having a connecting part belonging to the watertight connection zone and a receiving strip welded onto the connecting part;the receiving band extending from the bonding zone, away from the connecting part, in which a distal portion of the receiving band is welded to an end portion of the strakes of the membrane of the first tank wall, the receiving band of said first lateral wing having corrugated parts arranged in alignment with the longitudinal undulations of the strakes to terminate the longitudinal undulations of said strakes at a distance from the bonding zone.

[0021] Thanks to the corrugated sections of the receiving strip, which receive the ends of the longitudinal corrugations and seal them watertight by joining them to the flat section of the receiving strip, it is possible to maximize the length of the longitudinal corrugations along the strake. The flexibility of the corresponding watertight membrane introduced by the presence of the longitudinal corrugations is thus optimized. The specific shape of the corrugations described above helps to limit mechanical stress at the junction between the strakes and the receiving strip.

[0022] Thanks to these characteristics, the secondary and / or primary membrane exhibits appropriate flexibility, enabling it to withstand the thermal and mechanical stresses experienced during its use in the tank wall. The resulting tank is particularly robust.

[0023] Furthermore, it is possible to use strakes without longitudinal edges turned up towards the inside of the tank. This avoids producing a concentration of mechanical stresses at the junction between the upturned edges of the strake and the flat wing of the corner beam.

[0024] Alternatively, it is possible to use a strake comprising both at least one longitudinal corrugation and two raised edges. According to one embodiment, at least one or each of the corrugated parts is formed in one piece with said receiving strip, for example by stamping.

[0025] Thanks to these characteristics, it is possible to limit the number of parts required to manufacture the membrane.

[0026] According to one embodiment, at least one or each of the corrugated parts includes a piece attached to a flat part of the receiving strip of the lateral wing.

[0027] Thanks to these characteristics, the manufacture of the receiving strip does not require stamping.

[0028] According to one embodiment, the corrugated part has a shape adapted to cover the longitudinal end of a longitudinal corrugation and to extend it on the lateral wing towards the connection area.

[0029] According to one embodiment, the insulating barrier comprises insulating blocks and each strake comprises a longitudinal hooking element adapted to cooperate in retention with the insulating blocks of the insulating barrier to retain the strake in a thickness direction of the tank wall, while allowing movement of the strake along a longitudinal direction of the strake.

[0030] Thanks to these characteristics, the flexibility of the waterproof membrane is improved while ensuring a watertight assembly of the strakes.

[0031] According to one embodiment, the attachment element extends along a first longitudinal edge of the strake and includes a portion of the first longitudinal edge of the strake folded towards the insulating barrier and extending outwards from the flat portion of the strake.

[0032] According to one embodiment, the attachment element is welded to the first longitudinal edge of the strake. It will be understood that separating the attachment element from the strake facilitates positioning the strake along the length of the tank by first positioning the attachment element in conjunction with the insulating blocks, then positioning the strake, and finally welding the first longitudinal edge of the strake to the attachment element.

[0033] Thanks to these characteristics, each strake can be hooked onto the underlying insulating barrier.

[0034] According to one embodiment, the strake comprises, along its second longitudinal edge, a rim extending projecting from the flat portion of the strake, opposite the attachment element of the first longitudinal edge, the rim covering a part of the flat portion of an adjacent strake, the covered part extending along the first longitudinal edge of the adjacent strake.

[0035] Thanks to these characteristics, each strake can be welded to the adjacent strake.

[0036] According to one embodiment, the hooking element is received in a groove formed in the insulating barrier and opening onto the internal surface.

[0037] According to one embodiment, the hooking element cooperates in retention with a surface of a wall of the groove or with a retention element added in the groove.

[0038] According to one embodiment, part of the hooking element is received in a groove formed in a lateral face of the insulating blocks forming the insulating barrier.

[0039] According to one embodiment, the hooking element is received in a space separating two adjacent insulating blocks.

[0040] According to one embodiment, the hooking element cooperates in retention with a complementary hooking element which extends into the space separating the two adjacent insulating blocks.

[0041] According to embodiments, at least one of the strakes, some of the strakes, or each strake comprises one or two longitudinal undulations.

[0042] Alternatively, it is possible to provide for a number greater than two of undulations.

[0043] The structure described above can be used to make a secondary waterproof membrane and / or a primary waterproof membrane of a sealed and thermally insulating tank.

[0044] According to one embodiment, the waterproof membrane constitutes a secondary waterproof membrane and is surmounted by a primary insulating barrier and a primary waterproof membrane. The primary waterproof membrane may be similar to this secondary waterproof membrane or have a different structure.

[0045] According to one embodiment, the primary membrane comprises a plurality of primary strakes, each primary strake having a flat portion resting on an internal surface of the primary insulating barrier and two primary longitudinal raised edges projecting inward from the flat portion of the primary strake. According to another embodiment, the primary membrane has corrugations in two intersecting directions.

[0046] According to one embodiment, the primary watertight membrane comprises a plurality of primary struts, each primary strut having a flat portion resting on an internal surface of the primary insulating barrier and at least one primary longitudinal portion projecting inward from the flat portion of the primary strut, the primary struts being juxtaposed and welded together watertight at said longitudinal edges, the metal corner beam further comprising a first primary lateral flange parallel to the first wall load-bearing and a second primary lateral wing parallel to the second load-bearing wall, the two primary lateral wings being connected to each other at a primary watertight bonding zone, at least one or each of the first and second primary lateral wings of the corner beam having a receiving strip extending from the primary watertight bonding zone, away from the primary watertight bonding zone, wherein a distal portion of the receiving strip of the primary lateral wings of the corner beam is welded to an end portion of the primary strakes of the primary watertight membrane, the receiving strip of the primary lateral wings having corrugated portions arranged in alignment with the primary longitudinal portions of the primary strakes to terminate the primary longitudinal portions away from the primary watertight bonding zone.

[0047] For example, it is envisaged to preferably use corrugated strakes without raised edges in manganese alloy for the secondary sealing membrane.

[0048] For the primary waterproof membrane, preferredly are Invar strips with raised edges without corrugation, or a corrugated membrane with or without raised edges in Invar, or corrugated strips with raised edges in manganese alloy.

[0049] Each primary longitudinal portion may include a longitudinal undulation or a raised edge.

[0050] According to one embodiment, the corner beam comprises at least two support wings, connected to each of the first and second load-bearing walls, said support wings being arranged substantially in line with the lateral wings of the corner beam.

[0051] According to one embodiment, the corner beam further comprises primary lateral wings and primary support wings connected to each of the first and second load-bearing walls and arranged substantially in line with the primary lateral wings of the corner beam.

[0052] According to one embodiment, the waterproof membrane constitutes a primary waterproof membrane and the insulating barrier constitutes a primary insulating barrier, and the tank wall comprises a secondary insulating barrier and a secondary waterproof membrane disposed between the primary insulating barrier and the supporting structure.

[0053] The secondary waterproof membrane may be similar to this primary waterproof membrane or have a different structure.

[0054] According to one embodiment, the strakes are made of an iron and manganese or nickel alloy having a coefficient of expansion less than or equal to 9.106 K*. This alloy generally makes it possible to reduce costs.

[0055] According to one embodiment, the width of the strakes of the waterproof membrane is equal to the width of the insulating blocks of the corresponding insulating barrier or equal to half the width of the insulating blocks of the corresponding insulating barrier.

[0056] According to one embodiment, the invention further provides a vessel for the transport of a fluid, the vessel comprising a double hull and one such as described above disposed in the double hull.

[0057] According to one embodiment, the invention further provides a transfer system for a fluid, the system comprising a vessel as described above, insulated pipes arranged to connect the tank installed in the hull of the vessel to a floating or land-based storage facility and a pump to drive a fluid through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

[0058] According to one embodiment, the invention further provides a method for loading or unloading a ship as described above, in which a fluid is conveyed through insulated pipes from or to a floating or land-based storage facility to or from the ship's tank. Brief description of the figures

[0059] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings.

[0060] Fig. 1 is a partial schematic perspective view of a corner area of ​​a sealed and thermally insulating tank according to a first embodiment, showing part of the secondary insulating barrier and the secondary sealing membrane;

[0061] Figure 2 is a partial schematic perspective view of a joining zone between the strakes and the lateral wing of the corner beam of a watertight and thermally insulating tank wall according to a variant of the first embodiment of [Fig.1] in which a single longitudinal undulation is provided per strake;

[0062] [Fig.3] is a schematic view of a detail of [Fig.1] or [Fig.2];

[0063] Fig. 4 is a schematic cross-sectional view of the tank wall of Fig. 1. showing a strake of the secondary waterproof membrane during assembly;

[0064] Figure 5 is an enlarged schematic view of a detail of the tank wall of the [Fig.4] after mounting the strake;

[0065] Figs. 6, 7, 8, and 9 are enlarged schematic cross-sectional views of a tank wall according to variants of the first embodiment;

[0066] Fig. 10 is a partial schematic perspective view of the first embodiment of Fig. 1, showing part of the primary and secondary insulating barriers and the primary and secondary waterproof membranes;

[0067] Fig. 11 is a partial schematic perspective view of a corner area of ​​a sealed and thermally insulating tank according to a second embodiment, showing part of the secondary insulating barrier and the secondary sealing membrane;

[0068] Fig. 12 is an enlarged schematic view of a part of the tank of Fig. 11;

[0069] Fig. 13 is another partial schematic perspective view of the angle area of the sealed and thermally insulating tank according to the second embodiment;

[0070] The [Fig. 14] is a partial perspective view of a corner area of ​​a sealed and thermally insulating tank according to a third embodiment;

[0071] The [Fig. 15] is a schematic cutaway representation of a methane tanker and a loading / unloading terminal for this tanker.

[0072] Figures 16 to 18 are schematic cross-sectional views of a tank wall conforming to other variants of the first embodiment.

[0073] Figures 19 and 20 are schematic views of two examples of the profile of a longitudinal undulation of a strake, in section along a transverse plane perpendicular to the longitudinal direction of the strake. Description of the implementation methods

[0074] The accompanying figures show different embodiments of a sealed and thermally insulating tank. Identical or corresponding elements of the tank shown in these figures will be referenced by identical symbols and will not be described each time.

[0075] Figures 1, 10, 11, 13 and 14 show a partial view of a first (Figures 1 and 10), a second ([Fig. 11] and 13) and a third ([Fig. 14]) embodiment of a sealed and thermally insulated tank for the storage and / or transport of a low-temperature liquid, such as tanks for the transport of Liquefied Petroleum Gas (also called LPG) having, for example, a temperature between -50°C and 0°C, or for the transport of Liquefied Natural Gas (LNG) at about -162°C at atmospheric pressure.

[0076] The fluid is in particular a cryogenic fluid transported at low temperatures. It may be a liquefied gas, in particular a liquefied natural gas (LNG), that is to say a gaseous mixture consisting mainly of methane as well as one or more other hydrocarbons, such as ethane, propane, n-butane, i-butane, n-pentane, i-pentane, neopentane, and nitrogen in small proportion.

[0077] The liquefied gas can also be ethane or liquefied petroleum gas (LPG), that is to say a mixture of hydrocarbons from the refining of petroleum consisting essentially of propane and butane.

[0078] Alternatively, the liquefied gas can be ammonia (NH3) stored at -30°C at atmospheric pressure.

[0079] The sealed and thermally insulating tank is integrated into a supporting structure 4. The supporting structure 4 comprises a plurality of load-bearing walls 1, 2 defining the general shape of the tank, usually a polyhedral shape. It notably includes a first load-bearing wall 1 and a second load-bearing wall 2 joining the first load-bearing wall at an edge 3 of the supporting structure 4, forming a dihedral angle that could have different values. Here, an angle of 90° is shown (Figures 1, 10 and 11).

[0080] The load-bearing structure of the tank is here constituted by the inner hull of a double-hulled vessel. The first load-bearing wall 1 is, for example, a bottom wall of the vessel, while the second load-bearing wall 2 is, for example, a transverse bulkhead, which partially defines a compartment in the inner hull of the vessel.

[0081] The tank comprises a first tank wall fixed to the first load-bearing wall 1 and a second tank wall fixed to the second load-bearing wall 2.

[0082] Each of the first and second tank walls 1, 2 comprises at least one waterproof membrane 10 and an insulating barrier 20 interposed between the waterproof membrane 10 and the corresponding load-bearing wall 1, 2.

[0083] In Figures 1, 10, and 11, only the first tank wall is shown. Figures 13 and 14 show a portion of the second tank wall. The second tank wall can be identical to the first tank wall shown and described, except that it extends parallel to the second load-bearing wall 2 and not parallel to the first load-bearing wall 1, as is the case for the first tank wall. Only the first tank wall will be described hereafter.

[0084] Alternatively, it is possible to consider that the second tank wall has different characteristics.

[0085] In the case of the different embodiments represented and described below, the insulating barrier 20 can constitute a secondary insulating barrier 20 and the waterproof membrane 10 can constitute a secondary waterproof membrane 10. The secondary insulating barrier 20 is retained to the load-bearing wall 1, 2 and the secondary waterproof membrane 10 rests against the secondary insulating barrier 20.

[0086] Each tank wall of the first, second, and third embodiments described below further comprises a primary sealing membrane 10' intended to be in contact with the low-temperature liquid and a primary insulating barrier 20' disposed between the primary sealing membrane 10' and the sealing membrane Secondary 10. The primary insulating barrier 20' is retained on the secondary waterproofing membrane 10. A portion of the primary waterproofing membrane 10' and the primary insulating barrier 20' is shown in Figures 10 and 14 for the tank wall attached to the first load-bearing wall 1. The primary waterproofing membrane 10' and the primary insulating barrier 20' are optional. As will be described later, in the first and second embodiments, the primary layer of each tank wall, comprising the primary insulating barrier 20', the primary waterproofing membrane 10', and the structural elements for attaching them to the corresponding corner beam, is identical to the secondary layer of each tank wall, comprising the secondary insulating barrier 20, the secondary waterproofing membrane 10, and the structural elements for attaching them to the corresponding corner beam.

[0087] Alternatively, it may be envisaged that only the primary or secondary stage of the tank wall has the characteristics described below, and that the other stage has different characteristics, for example, in accordance with the prior art. In the third embodiment described with reference to [Fig. 14], the primary membrane 10' is different from the secondary membrane 10 and does not have longitudinal undulations. The primary membrane here comprises a plurality of primary struts, each having a flat portion resting on an internal surface 21' of the primary insulating barrier 20' and two primary longitudinal raised edges 418' projecting towards the interior of the tank relative to the flat portion of the primary strut, without undulation.

[0088] It can also be envisaged that one and / or the other of the primary and secondary watertight membranes comprise several types of striations, namely striations without corrugations and striations with corrugations.

[0089] The tank can thus include walls comprising different zones, for example: - one or more zones in which the strakes used for the primary and / or secondary sealing membrane do not have any undulation, located for example in regions close to the edges of the tank, - one or more zones in which the strakes used for the primary and / or secondary sealing membrane have one or more undulations, located for example in the areas of the tank walls far from the edges of the tank.

[0090] The primary insulating barrier 20' and / or secondary insulating barrier 20 is formed by the juxtaposition of insulating blocks 22, 22'. These insulating blocks 22, 22' generally have a parallelepiped shape with two main faces 21A, 21B parallel to the load-bearing wall 1, 2 to which the corresponding tank wall is fixed. The two main faces 21A, 21B are connected by lateral faces 21C ([Fig. 4]). The insulating blocks 22, 22' of each insulating barrier are aligned regularly with each other and delimit spaces 28 (Figures 4 and 9) filled by insulating joints. In the first and third embodiments, retaining devices 50 ([Fig.4]) are arranged at the corners of the insulating blocks 22, 22' and anchor four adjacent insulating blocks 22 in the corresponding load-bearing wall 1.

[0091] Such retaining devices 50 can be made in different ways and are described for example in more detail in document WO2019 / 110894.

[0092] Each retaining member 50 includes a stud 372 which passes through a bore 11A formed through a strut 11, 11' of the secondary sealing membrane 10. The stud has a collar which is welded to its periphery, around the bore, to ensure the sealing of the secondary sealing membrane 10. The secondary sealing membrane 10 is sandwiched between the collar of the stud and a load distribution plate of the retaining member 50 (not shown in [Fig.4], visible in [Fig. 13]).

[0093] Each retaining element 50 is anchored to a load-bearing wall.

[0094] The main faces 21A, 21A' of the insulating blocks facing the interior of the tank form the internal surface 21,21' of the primary or secondary insulating barrier 20', 20.

[0095] The insulating blocks 22, 22' can be made in various ways. Each insulating block 22, 22' comprises, for example, a base plate 23 and a cover plate 24, as well as at least one layer of thermally insulating foam 25 interposed between the base plate 23 and the cover plate 24 ([Fig. 4]). This is the case here for the first and second embodiments. Such insulating blocks can be made in various ways and are described, for example, in more detail in WO2021239767.

[0096] The foam layer 25 is arranged between the cover plate 24 and the base plate 23.

[0097] The base plates 23 and lid plates 24 are glued onto the foam layer(s) 25.

[0098] Thermally insulating foam is for example a polyurethane foam, optionally reinforced with glass fibers, having for example a density of the order of, or even greater than, 110 kg.m3.

[0099] The foam layer 25 has at each of its corners a recess intended to receive the retaining member 50 visible in figures 1 and 4.

[0100] The insulating blocks 22, 22' can also be made of boxes filled with insulating material, as in the third embodiment of [Fig. 14].

[0101] At the angle between the two tank walls, the secondary sealing membranes 10 of the two tank walls and the primary sealing membranes 10' of the two tank walls are connected in a watertight manner by a connecting ring in the form of an angle beam 30; 330; 430 which allows the forces to be absorbed tension resulting from thermal contraction, hull deformation at sea, and cargo movements. Possible structures of the angle beam 30, 330, and 430 are described further in FR2549575 or WO2021074435.

[0102] In the first embodiment of [Fig. 1] and the third embodiment of [Fig. 14], the angle beam 30, 430 comprises, for example, four metal cross profiles connected by metal plates to form a square-section tube 36; 436. This square-section tube 36; 436 is connected by first anchoring flanges 37A, 37B to the first load-bearing wall 1 and by second anchoring flanges 37C, 37D to the second load-bearing wall 2. The first anchoring flanges 37A, 37B extend parallel to the second load-bearing wall 2 and the second anchoring flanges 37C, 37D extend parallel to the first load-bearing wall 1. The first and second anchoring flanges anchor the angle beam 30; 430 to the load-bearing structure 4.

[0103] Alternatively, depending on the shape of the tank, the beam may also be a tube with a different cross-sectional shape. For example, in a parallelepiped-shaped tank, the beam may consist of a tube with a rhombus cross-section.

[0104] To make the angle beam 30; 430 all along the edge 3, it is preferable to use several successive segments, the length of which is adapted to the handling conditions, for example 1 to 3 meters per segment, as can be seen in [Fig.1].

[0105] In addition, insulating pieces are preferably provided between the load-bearing walls and the corner beam and / or inside the corner beam when the latter is in the form of a square-section tube.

[0106] The secondary sealing membrane 10 comprises a plurality of secondary strakes 11; 411 assembled together in a sealing manner and the primary sealing membrane 10' comprises a plurality of primary strakes 11'; 411' assembled together in a sealing manner.

[0107] Each secondary strut 11,411 and each primary strut 11', 411' is in the form of an elongated metal strip along a longitudinal direction D. It is delimited by two longitudinal edges 14A, 14B, 14A', 14B'; 414A, 414B, 414A', 414B' extending parallel to the longitudinal direction D of the secondary strut 11; 411 or primary strut 11'; 411' and by two end edges 15, 16, 15', 16'; 415, 415' which extend perpendicularly to the longitudinal direction D.

[0108] Each primary strut 11', 411' or secondary 11,411 typically extends for several tens of meters along the longitudinal direction D and extends over a width, perpendicular to the longitudinal direction, of between 40 cm and 1.5 meters, for example equivalent to the width of an insulating block 22 or to half the width of an insulating block 22.

[0109] Preferably, each strake extends longitudinally over the entire dimension of the tank wall to which it belongs, from a tank wall adjacent to the tank wall in question to another tank wall adjacent to the tank wall in question.

[0110] The secondary strakes 11; 411 and primary strakes 11', 411' are juxtaposed parallel and welded together in a watertight manner at the level of said longitudinal edges 14A, 14B, 14A', 14B'; 414A, 414B, 414A', 414B' as will be described in more detail later.

[0111] The strakes 11, 11'; 411, 411' are, for example, made of Invar®, i.e., an iron-nickel alloy whose coefficient of thermal expansion is typically less than or equal to 2 x 10⁶ K⁻¹, preferably between 1.2 x 10⁶ and 2 x 10⁶ K⁻¹. In this case, the strakes may, for example, have a thickness of approximately 0.7 millimeters (mm). Alternatively, the strakes may be made of an iron-manganese alloy whose coefficient of thermal expansion is typically less than or equal to 9 x 10⁶ K⁻¹, preferably between 7 x 10⁶ and 9 x 10⁶ K⁻¹. In the case of a ship's tank, the strakes are preferably oriented parallel to the longitudinal direction of the ship.

[0112] In the first and second embodiments described herein, the primary watertight membrane 10' is similar to the secondary watertight membrane 10. The flanges of the two membranes are preferably made of a high-manganese iron alloy whose coefficient of thermal expansion is typically less than or equal to 9.106 K₁, preferably between 7.106 and 9.106 K₁. The flange thickness is constant and between 0.5 and 1.5 millimeters.

[0113] Each secondary strake 11 and primary strake 11' comprises a flat portion 12, 12' resting on the inner surface 21, 21' of the insulating barrier 20, 20' and at least one longitudinal corrugation 13, 13' projecting towards the interior of the tank relative to the flat portion 12 of the strake 11. In the first and second embodiments, two longitudinal corrugations 13, 13' are provided per secondary strake 11 (Figures 1 and 11) or primary strake 11' ([Fig. 10]). [Fig. 2] shows a variant of the first embodiment, in which a single longitudinal corrugation 13 is provided per secondary strake 11.

[0114] Preferably, one, two, or more longitudinal corrugations are provided, excluding other corrugations extending in a different direction. In other words, the strake comprises one or more corrugations only in the longitudinal direction.

[0115] Said or each longitudinal corrugation 13, 13' is spaced from the longitudinal edges 14A, 14B, 14A', 14B' of the strake 11, 11'. In practice, each longitudinal undulation 13, 13' is for example spaced from the longitudinal edge 14A, 14B, 14A', 14B' of the strake 11, 11' by at least 50 mm, for example 125 mm or 170 mm or 250 mm depending on the number of undulations per strake and the width of the strakes namely about 500 mm or 1000 mm with a tolerance of 20 mm.

[0116] Said or each longitudinal undulation 13, 13' comprises here - two concave curved parts 131 connected to an element 125A, 125B of the flat portion 12 of the strake, - a central flat part 132 at the apex of the undulation 13 and - two convex curved parts 133 each connecting one end of the central flat part to a said concave curved part.

[0117] Figures 19 and 20 show the profiles of two examples of the realization of said or each undulation of the strake 13, 13'.

[0118] The concavity of the curved parts of the corrugation is defined with respect to the space delimited inside the tank by the corrugation, that is to say, the inner side of the strake 11, oriented towards the load-bearing structure 4 of the tank. The concave curved parts 131 form a hollow in the inner face of the strake 11, oriented towards the inside of the tank, while the convex curved parts 133 form a bulge in this inner face.

[0119] More specifically, only two concave curved parts 131 and only two convex curved parts 133 are provided, to the exclusion of any other concave or convex curved part.

[0120] The longitudinal undulation 13 extends longitudinally from one end edge 15 to the other end edge 16 of the strake 11.

[0121] It extends laterally, in a direction perpendicular to the longitudinal direction D and parallel to the flat portion 12 of the strake 11, between two extreme zones of the longitudinal undulation 13. A first extreme zone is located at the junction of a first concave curved part 131 with one of the elements 125A of the flat portion 12 of the strake 11 and a second extreme zone is located at the junction of the second concave curved part 131 with the other element 125B of the flat portion 12 of the strake 11.

[0122] The longitudinal undulation 13 has a median plane of symmetry PM. The central flat portion 132 extends parallel to the flat portion 12 of the strake 11.

[0123] The concave curved parts 131 and convex parts 133, as well as the central flat part 132 and any lateral parts 134, extend along the entire longitudinal direction D of the undulation. Their cross-sections in a transverse plane PP perpendicular to the longitudinal direction D (shown in [Fig. 3]) are invariant under translation in the longitudinal direction D.

[0124] In each of the two embodiment examples shown in Figures 19 and 20, each concave curved part 131 of said or each longitudinal undulation 13, 13' is connected to one of the two convex curved parts 133 of the longitudinal undulation 13 by a lateral planar part 134 of the longitudinal undulation 13.

[0125] The lateral flat parts 134 form an angle Al with the median plane PM between 20 and 40 degrees, for example equal here to 30 degrees.

[0126] Alternatively, each concave curved portion of said or each undulation is directly connected to one of the two convex curved portions of the undulation. In other words, each concave curved portion is connected to one of the two convex curved portions without a planar lateral portion. The cross-section along the transverse plane of each concave curved portion is connected to the cross-section along this plane of one of the two convex curved portions at an inflection point of the undulation profile.

[0127] In addition, the section along the plane perpendicular to said longitudinal direction of each concave curved part and each convex curved part of said or each longitudinal undulation 13 presents here a circular arc shape.

[0128] The radius of curvature RI; RI', R2; R2' of each of said sections is preferably between 5 and 15 millimeters.

[0129] In the examples in Figures 19 and 20, the radii of curvature of the concave curved parts R2; R2' and convex curved parts RI; RI' are different or equal to each other and equal to 7.5 or 10 millimeters. In Figures 19 and 20, the radii of curvature of the concave curved parts R2; R2' and convex curved parts RI; RI' are equal to each other and equal to 10 millimeters.

[0130] The arc section of each concave curved part 131 and convex part 133 extends over an angle A2, A3; A2', A3' between 10 and 80 degrees of arc.

[0131] In the first example of [Fig. 19], the circular arc section of each concave curved part 131 extends over an angle A3 of between 45 and 70 degrees of arc. The circular arc section of each convex curved part 133 extends over an angle A2 of between 45 and 70 degrees of arc, for example 60 degrees of arc.

[0132] In the second example of [Fig. 20], the circular arc section of each concave curved part 131 extends over an angle A3' of between 45 and 70 degrees of arc, for example 60 degrees of arc. The circular arc section of each convex curved part 133 extends over an angle A2' of between 45 and 70 degrees of arc, for example 60 degrees of arc.

[0133] Said central flat parts 132 and lateral parts 134 and the concave curved parts 131 or the convex curved parts 133 of said or each longitudinal undulation 13 extend one another in such a way that the profile of said or each longitudinal undulation 13 has a slope varying continuously in the transverse plane PP. In other words, the sections of the concave curved parts 131 and The convex sections 133, as well as the sections of the central flat parts 132 and, where present, the sections of the lateral flat parts 134, extend continuously into one another without defining a sharp edge. The profile of the undulation is thus devoid of a sharp edge.

[0134] Said or each longitudinal corrugation 13 extends laterally, in the direction perpendicular to the longitudinal direction D of the longitudinal corrugation 13 and parallel to the flat portion 12 of the strake 11, over a total width DI; Dl', measured from the first end zone of the longitudinal corrugation 13 to the second end zone of the corrugation, which is between 30 and 70 millimeters.

[0135] In the first example of [Fig. 19], the total width Dl of the longitudinal undulation 13 is equal to 50 millimeters with a tolerance of 5 millimeters.

[0136] In the second example of [Fig.20], the total width Dl' of the longitudinal undulation 13 is equal to 40 millimeters with a tolerance of 5 millimeters.

[0137] Said or each longitudinal undulation 13 extends vertically, along a thickness direction E of the tank, over a total height H; H' measured between the flat portion 12 of the strake 11 and the central flat part 132; 132' of the longitudinal undulation 13 between 8 and 17 millimeters.

[0138] In the first example of [Fig. 19], the total height H of the longitudinal undulation 13 is equal to 12 or 15 millimeters with a tolerance of 1 millimeter.

[0139] In the second example of [Fig.20], the total height H' of the longitudinal undulation 13 is equal to 9 millimeters with a tolerance of 1 millimeter.

[0140] Reducing the height of the corrugation 13 makes it possible to limit the depth of the groove that must be cut in the primary insulating block located above the strake 11 to accommodate the longitudinal corrugation.

[0141] The central flat part 132 of said or each longitudinal corrugation 13 extends laterally, in the direction perpendicular to the longitudinal direction D of the longitudinal corrugation 13 and parallel to the flat portion of the strake, over a central width D2; D2' between 4 and 30 millimeters, preferably between 5 and 12 millimeters.

[0142] In the first example of [Fig. 19], the central width D2 of the longitudinal undulation 13 is equal to 9 millimeters with a tolerance of 3 millimeters.

[0143] In the second example of [Fig. 20], the central width D2' of the longitudinal corrugation 13 is equal to 9 millimeters with a tolerance of 3 millimeters. The hole 11A in the strake through which the stud of the retaining member 50 passes is located on a longitudinal median area of ​​a flat portion 12, 12' of the strake 11, 11'. It is preferably located in the middle of the strake 11, 11' according to its width, at a distance from the corrugation(s) 13, 13' of the strake 11, 11'.

[0144] The stud of the retaining member 50 protrudes above the corresponding strake 11, 11' for the attachment of the primary insulating barrier 20'.

[0145] In the third embodiment, the secondary strakes 411 of the secondary sealing membrane 10 have the characteristics described above: they comprise a flat portion 412 resting on the internal surface 21 of the insulating barrier 20 and at least one longitudinal corrugation 413 projecting towards the inside of the tank relative to the flat portion 412 of the strake 11. Two longitudinal corrugations 413 are provided per strake 411. In addition, the longitudinal edges 414A, 414B of each strake 411 are raised, i.e. folded towards the inside of the tank.

[0146] Each longitudinal corrugation 413 of the secondary strake 411 of the tank according to the third embodiment has the characteristics of the longitudinal corrugations 13 of the primary and secondary strakes 11, 11' of the first and second embodiments described above. In particular, each longitudinal corrugation 413 of the third embodiment may have a profile identical to those shown in Figures 19 and 20.

[0147] The secondary strakes 411 are preferably made of a high manganese iron alloy whose coefficient of expansion is typically less than or equal to 9.106 K l, preferably between 7.106 and 9.106 K '. The thickness of the strake is constant and between 0.5 and 1.5 millimeters.

[0148] The primary strakes 411' of the primary waterproof membrane 10' of the third embodiment do not exhibit any longitudinal undulation and have raised longitudinal edges 414A', 414B'.

[0149] The primary strakes 411' are, for example, made of Invar®, that is to say an alloy of iron and nickel whose coefficient of expansion is typically less than or equal to 2.106 K*, preferably between 1.2.106 and 2.106 K'.

[0150] The corner beam 30; 330; 430 further comprises a first lateral flange 31; 331; 431 parallel to the first load-bearing wall 1 and a second lateral flange 32 parallel to the second load-bearing wall 2. The two lateral flanges allow the attachment of the secondary waterproof membranes 10.

[0151] The two lateral wings 31, 32; 331; 431 are linked to each other at a watertight connection zone 33; 333; 433 of the corner beam 30; 330; 430.

[0152] In addition, each strake 11, 11' ; 411, 411' has a cross-section along the transverse plane PP which is invariable along the longitudinal direction D. In other words, the profile of each strake 11, 11' ; 411, 411' is uniform.

[0153] The arrangement of the secondary waterproof membranes of the first and third embodiments is described hereafter.

[0154] In the case of the first embodiment of Figures 1 and 10 and the third embodiment of [Fig. 14], in which a corner beam forming a square-section tube is provided, the watertight connection zone 33; 433 has a stepped shape, comprising the metal plates of the corner beam 30; 430 forming the internal angle of the corner beam oriented towards the center of the tank, namely the connecting parts 31A and 32A and the two metal plates of the square-section tube that extend and connect the connecting parts 31A and 32A. Further details on the watertight connection zone can be found in publication WO2021074413.

[0155] Each lateral wing 31, 32; 431 of the angle beam 30; 430 extends in line with one of the anchor wings 37B, 37C of the angle beam 30; 430.

[0156] Each of the first and second lateral flanges 31, 32, 431 of the angle beam 30, 430 comprises a connecting portion 31A, 32A, 431A formed with the square-section tube 36, 436 and a receiving strip 34, 434 welded to the connecting portion 31A, 32A, 431A, which extends from the connection zone 33, 433, away from the connection zone 33, 433 in line with the corresponding connecting portion 31A, 32A, 431A. In [Fig. 1], only a portion of the receiving strip 34 of the lateral flange 31 parallel to the first load-bearing wall 1 is shown.

[0157] The receiving strip 34; 434 of the lateral wing 31, 32; 431 of the angle beam 30; 430 is made by a series of furring strips having an end edge 34B; 434B welded continuously to the connecting part 31 A, 32A; 431A of the angle beam 30; 430 to take up the tensile forces.

[0158] The receiving strip 34; 434 comprises a flat portion 34C; 434C which extends in the continuation of the corresponding connecting portion 31A, 32A; 431 and a distal portion 34A; 434A welded continuously and tightly to an end portion of the strakes 11; 411. This distal portion 34A; 434A corresponds to the edge of the receiving strip 34; 434 opposite the end edge 34B; 434B welded to the connecting portion 31A, 32A; 431A of the lateral wing 31, 32; 431 of the corner beam.

[0159] The distal portion 34A, 434A of the receiving strip 34; 434 covers the end edge 15; 415 of each strake 11; 411. It forms for this purpose a sidewalk whose height is substantially equal to the thickness of the strake 11, 411, so that the flat part 34C; 434C of the receiving strip 34; 434 extends in the same plane as the flat part of the strakes 11; 411.

[0160] The end edge 15; 415 of each strake 11; 411 has a complex profile because each longitudinal undulation 13; 413 of the strake 11; 411 extends to this end edge 15; 415. The longitudinal undulation 13; 413 has a constant height over its entire length.

[0161] Thus, the receiving band 34; 434 of the lateral wings 31, 32; 431 has wavy parts 35; 435 arranged in alignment with the longitudinal undulations 13; 413 of the strakes 11; 411 to terminate the longitudinal undulations 13; 413 at a distance from the bonding zone 33; 433.

[0162] Each corrugated portion 35; 435 extends from the distal portion 34A, 434A of the receiving strip, towards the connecting portion of the angle beam 30; 430, over a distance preferably greater than 70 mm and less than 800 mm. This distance is preferably less than half the width of the receiving strip measured between the free edge of the distal portion 34A; 434A and the end edge 34B; 434B).

[0163] The distance over which the corrugated portion 35; 435 extends is greater the larger the width of the receiving strip. This makes it possible to reduce the stresses in the direction parallel to the edge.

[0164] Each corrugated part 35; 435 has a shape adapted to cover the longitudinal end of a longitudinal corrugation 13; 413 and to extend it on the lateral wing 31, 32; 431 towards the connection zone 33; 433.

[0165] More specifically, as is particularly visible in [Fig.3] in the case of the first embodiment, the corrugated part 35 of the receiving strip 34 can be formed with the receiving strip 34. It is for example produced by stamping the metal plate forming the receiving strip 34. The receiving strip is for example made of one of the iron and nickel or iron and manganese alloys described above.

[0166] The corrugated part 35 of the receiving strip includes, along the distal portion 34A of the receiving strip, a first part 35A whose surface oriented towards the strake has a shape adapted to follow the contour of the longitudinal corrugation 13. The corrugated part 35 also includes a second part 35B which continuously connects the first part 35A of the corrugated part 35 to the flat part 34C of the receiving strip 34.

[0167] Thus, more precisely, the first part 35A of the corrugated part 35 of the receiving strip comprises two concave curved parts 351 connected to the flat part 34C of the receiving strip 34, a central flat part 352 located at the top of the corrugated part 35 and two convex curved parts 353 each connecting one end of the central flat part 352 to a said concave curved part 351 of the first part of the corrugated part 35 ([Fig.3]).

[0168] The receiving band 435 of the third embodiment can be made in a similar manner.

[0169] As mentioned previously, the tank wall may comprise only a single insulating barrier and a single waterproof membrane such as that described above.

[0170] When the tank wall further comprises a primary insulating barrier 20' and a primary waterproof membrane 10', these can be made in a manner entirely similar to the secondary insulating barrier 20 and the secondary waterproof membrane 10 described above, as is the case in the first embodiment ([Fig. 10]). As shown in [Fig. 10], the primary insulating blocks 22' can be arranged in alignment with the insulating blocks of the secondary insulating barrier 20. They are fixed to the secondary waterproof membrane 10.

[0171] The angle beam 30 then includes two other lateral wings parallel to the first load-bearing wall 1 and second load-bearing wall 2 for the attachment of the primary strakes 11' of the primary membrane 10'.

[0172] The two lateral wings are linked to each other at the level of the watertight connection zone 33 of the corner beam 30 and extend in the continuation of one of the anchoring wings 37B, 37C of the corner beam 30.

[0173] Each of the other lateral wings comprises a primary connecting portion 31A', 32A' formed with the square-section tube 36 and a primary receiving strip 34' welded to the primary connecting portion 31A', 32A', which extends from the connection zone 33, away from the connection zone 33 in line with the corresponding primary connecting portion 31A', 32A'. In [Fig. 11], only a portion of the primary receiving strip 34' of the other lateral wing parallel to the first load-bearing wall 1 is shown.

[0174] The primary receiving band 34' of the primary stage is made in a similar manner to the receiving band 34 of the secondary stage.

[0175] The primary watertight membrane 10' is made in a similar manner to the secondary watertight membrane 10, by a series of primary strakes 11' identical to the secondary strakes 11 of the secondary watertight membrane 10, as described above. The strakes 11' include, in particular, one or two longitudinal corrugations 13'.

[0176] Thus, the primary receiving strip 34' comprises a flat portion 34C' which extends in line with the corresponding primary connecting portion 31A', 32A' and a distal portion 34A' welded continuously and tightly to an end portion of the primary strakes 11'. This distal portion 34A' corresponds to the edge of the primary receiving strip 34' opposite the end edge 34A' welded to the primary connecting portion 31A', 32A'.

[0177] The primary receiving band 34' has corrugated parts 35' arranged in alignment with the longitudinal undulations 13' of the primary striations 11' of the primary membrane 10' to terminate the longitudinal undulations 13' away from the bonding zone 33.

[0178] The attachment of the primary strakes 11' of the primary waterproof membrane 10' to the insulating blocks of the primary insulating barrier can be carried out in a manner similar to the attachment of secondary vines 11, which will be described later with reference to figures 4 to 9.

[0179] Alternatively, the insulating blocks 22' of the primary insulating barrier 20' can be arranged in a staggered pattern, straddling four adjacent secondary insulating blocks. In this case, the fixing elements protruding from the secondary insulating barrier are provided. This is the case, for example, in the second embodiment of Figures 11 and 13.

[0180] According to this second embodiment, the corner beam 330 comprises a single metal cross profile connected by anchoring wings 337A, 337B to the first and second load-bearing wall 1, 2.

[0181] The corner beam 330 has the first lateral wing 331 parallel to the first load-bearing wall 1 and the second lateral wing 332 parallel to the second load-bearing wall 2.

[0182] The two lateral wings 331, 332 are linked to each other at the level of the watertight connection zone 333 of the corner beam 330.

[0183] In the case of the second embodiment of [Fig.1 1], the connection zone 333 corresponds to the angle of the cross profile connecting the lateral wings 331, 332.

[0184] Each lateral wing 331, 332 of the angle beam 30 extends in line with one of the anchor wings 337B, 337C of the angle beam 330.

[0185] Each of the first and second lateral wings 331, 332 of the angle beam 330 includes a connecting part 331 A, 332A formed with the cross profile and a receiving strip 334 welded onto the connecting part 331 A, 332A, which extends from the connection zone 333, away from the connection zone 333 in the extension of the corresponding connecting part 331 A, 332A.

[0186] The receiving strip 334 comprises a flat portion 334C which extends in the continuation of the corresponding connecting portion 331 A, 332A and a distal portion 334A welded continuously and tightly to an end portion of the strakes 11. This distal portion 334A corresponds to the edge of the receiving strip 334 opposite the end edge 334B welded to the connecting portion 331 A, 332A of the lateral wing 331, 332 of the corner beam 330.

[0187] The secondary waterproof membrane 10 comprises a plurality of secondary strakes 11 as described above, assembled together in a waterproof manner.

[0188] Each secondary strake 11 comprises, as described above, a flat portion 12 resting on the internal surface 21 of the insulating barrier 20 and at least one longitudinal undulation 13 projecting towards the interior of the tank relative to the flat portion 12 of the strake 11. Here, two longitudinal undulations 13 are provided per secondary strake 11.

[0189] In the second embodiment, the distal portion 334A of the receiving strip 334 extends in line with the flat portion 334C. This distal portion 334A is covered by an end edge 15 of each secondary strake 11. The end edge 15 of each secondary strake 11 forms a ledge between two longitudinal corrugations 13. The height of this ledge is substantially equal to the thickness of the flat portion of the receiving strip 334, so that the flat portion 334C of the receiving strip 334 extends in the same plane as the flat portion 12 of the secondary strakes 11.

[0190] In addition, the receiving band 334 of the lateral wings 331, 332 has wavy parts 335 arranged in alignment with the longitudinal undulations 13 of the secondary strakes 11 to terminate the longitudinal undulations 13 at a distance from the bonding zone 333.

[0191] Each corrugated part 335 has a shape adapted to cover the longitudinal end of a longitudinal corrugation 13 and to extend it on the lateral wing 331, 332 towards the connection area 333.

[0192] More specifically, the corrugated part 335 here includes an added piece on the flat part 334C of the receiving strip 334 of the lateral wing 331, 332. This added piece is shown more particularly in [Fig. 12].

[0193] It comprises a horseshoe-shaped base 336, having a first flat portion 336A applied against the flat portion 334C of the receiving strip 334 and a free edge 337 connected to the first flat portion 336A by a notch 337A so as to form a walkway. The free edge 337 covers the end edge 15 forming the walkway of the secondary strake 11 located outside the longitudinal corrugation(s) 13.

[0194] The height of the step 337A is substantially equal to the thickness of the secondary strake 11, so that the flat part 336A of the base 336 extends in the same plane as the end edge of the secondary strake 11.

[0195] The base 336 is continuously connected to a curved part 338 of the corrugated part 335 adapted to follow the shape of the longitudinal undulation 13 of the strake.

[0196] The curved part 338 of the corrugated part 335 of the receiving strip 334 thus comprises two concave curved parts 361 connected to the flat part 334C of the receiving strip 334, a central flat part 362 located at the top of the corrugated part 335 and two convex curved parts 363 each connecting one end of the central flat part 362 to a said concave curved part 361 of the curved part 338 of the corrugated part 335 ([Fig. 12]).

[0197] The free edge 337 and the curved part 338 of the corrugated part 335 are welded to the end edge 15 of the secondary strake in a watertight manner, while the first flat part 336A of the base 336 of the corrugated part 335 is welded to the receiving strip 334.

[0198] This arrangement offers the same advantages as those provided by the corrugated portion stamped into the receiving belt. Furthermore, it can be implemented without stamping the receiving belt, simply by adding extra parts to form the corrugated sections.

[0199] In this second embodiment the tank wall may further comprise a primary stage.

[0200] In this case, the corner beam 330 further comprises primary corner pieces, as described, for example, in WO2021074435. Each primary corner piece has an angle-shaped insulating piece with two perpendicular flanges whose thickness is substantially equal to the thickness of the primary insulating barrier. A metal angle bracket is fixed to the upper surface of the insulating piece, along the corner. The insulating piece can be made in various ways, for example, of solid plywood; of one or more blocks of a sandwich structure made of one or more layers of polymer foam and one or more rigid panels, for example, of plywood; or in the form of one or more boxes filled with insulating material. The metal angle bracket forms the first and second lateral flanges of the corner beam, which includes the strake-receiving strip.

[0201] For fixing the primary insulating barrier 20' and the primary waterproof membrane 10' (not shown), threaded studs 371 are carried by the receiving strip 334 to fix the primary corner pieces (not shown).

[0202] The fixing of the primary corner pieces by the threaded studs can be carried out in different ways, for example as described in WO2018087466.

[0203] Threaded studs 372 are also fixed to the secondary insulating blocks to form retaining elements for primary insulating blocks 22'.

[0204] In the third embodiment of the sealed and thermally insulating tank shown in [Fig. 14], the secondary strakes 411 and primary strakes 411' have raised edges 418, 418'.

[0205] The secondary 10 and primary 10' waterproof membranes are each made up of a series of secondary 411 and primary 411' invar struts parallel to raised edges 418, 418', which are arranged alternately with elongated weld supports 419, 419', also invar. The weld supports 419, 419' are each time retained to the underlying insulating block 22, 22', for example by being housed in grooves 417, 417' formed in the cover plates 24 of the insulating blocks 22, 22'.

[0206] The insulating blocks 22, 22' are here for example made up of boxes filled with insulating material, for example perlite, glass wool or rock wool.

[0207] This alternating structure is implemented over the entire surface of the tank walls, which can involve very long lengths. Over these long lengths, the watertight welds between the raised edges 418, 418' of the secondary 411 and primary 411' strakes and the weld supports 419, 419' interposed between them can be made in the form of straight weld beads parallel to the tank wall.

[0208] The corner beam 430 is similar to that of the first embodiment.

[0209] The secondary strakes 411 and primary strakes 411' with raised edges 418, 418' are not directly connected to the corner beam 430. As in previous embodiments, a receiving strip 434 is interposed between them. The receiving strip 434, 434' has a flat portion and an end edge 434B, 434B' continuously welded to a connecting flange 431A of the corner beam 430 to resist tensile forces. The receiving strip 434, 434' comprises a plurality of raised-edge furring strips 439, 439'. The raised edges 439, 439' of the furring strips have a complex profile with an inclined portion that rises gradually from the end edge 434B towards the strakes 11, 11', followed by a horizontal portion whose height is equal to the height of the raised edges of the strakes. The furring strips are continuously and watertightly welded edge to edge at the upper edge of the raised edges 439, 439'.

[0210] The structure of this wall is described in more detail in document FR2968284.

[0211] Each secondary girdle 411 of the secondary membrane 10 here has two undulations 413 and the receiving band 434 of the secondary membrane 10 has corrugated parts 435 which terminate the longitudinal undulations 413.

[0212] The profile of the undulations 413 of each secondary strake 411 and the shape of the corrugated parts 435 of the receiving strip 434 have the characteristics described with reference to the first embodiment of the tank.

[0213] The secondary membrane 10 of the tank then combines the secondary strakes 411 with raised edges 418 and the longitudinal undulations 413, which provides a particular flexibility to this secondary membrane.

[0214] In all embodiments of the sealed and thermally insulating tank, the use of secondary 11 and / or primary 11' struts having longitudinal undulations along their entire length, made possible by the presence of corrugated parts terminating these longitudinal undulations at the level of the receiving strip, gives flexibility to the secondary and / or primary membrane allowing it to withstand the thermal and mechanical stresses suffered during its use in the tank wall.

[0215] Thanks to the corrugated portions 35; 335; 435 of the receiving strip 34; 334; 434, which receive the ends of the longitudinal corrugations 13; 413 and terminate them continuously by joining with the flat portion 34C; 334C; 434C of the receiving strip 34; 334; 434, it is possible to maximize the length of the longitudinal corrugation 13; 413 along the welt 11; 411. The flexibility of the membrane The corresponding watertight seal introduced by the presence of longitudinal undulations is thus optimized.

[0216] In the first and second embodiments, thanks to the presence of the longitudinal corrugations 13 along the entire length of the strakes 11 of the secondary watertight membrane 10, it is also possible to use strakes without longitudinal edges raised towards the inside of the tank. This limits the stress concentration observed at the junction between the secondary strakes and the receiving strip when the secondary strakes have raised longitudinal edges.

[0217] Furthermore, the particular shape of the longitudinal corrugations of the strakes described above, which have a flat section at their apex, helps to limit the mechanical stresses experienced by the watertight membrane formed by these strakes, particularly at the joint between the strakes and the receiving strip. The flexibility of the watertight membrane, and therefore the mechanical strength of the tank, is thus improved.

[0218] For the assembly and watertight connection of the secondary strakes 11 and / or primary strakes 11' which do not have raised edges between them, various solutions can be considered. Several solutions are shown for example in Figures 4 to 9 and 16 to 18 and are described below with reference to the secondary strakes 11 of the first embodiment of [Fig. 1].

[0219] As shown in Figures 4 and 5, according to a first variant of the first embodiment, each secondary strut 11 has a width equivalent to the width of an insulating block 22 of the secondary insulating barrier 20. Each secondary strut 11 is arranged straddling two insulating blocks 22 and covers half of each insulating block 22.

[0220] For attaching the secondary strakes 11 to the insulating blocks 22, the cover plate 24 of each insulating block 22 has a groove 26 formed in the internal surface 21 of the secondary insulating barrier 20. More precisely, the groove 26 is formed in the cover plate 24 of each insulating block 22. It extends parallel to the longitudinal direction D of the secondary strakes 11 and has an inverted T-shaped profile. The groove 26 thus has the advantage of being symmetrical.

[0221] Each secondary strake 11 has a longitudinal hooking element 40 adapted to cooperate with the insulating blocks 22 of the secondary insulating barrier 20 to retain the secondary strake 11 in the direction of the thickness of the tank wall, while allowing movement of the secondary strake 11 along the longitudinal direction D of the secondary strake 11.

[0222] The attachment element 40 extends along a first longitudinal edge 14A of the secondary strake 11 and includes a portion of the first longitudinal edge 14A of the secondary strake 11 folded towards the insulating barrier 20 and extending outwards from the flat portion 12 of the secondary strake 11. This variant is represented in a more detailed on [Fig.5]. The first longitudinal edge 14A forming the attachment element 40 includes a longitudinal drop wall 41 which extends from part of the flat portion 12 of the secondary strake 11 and is folded at a right angle to the flat portion 12 of the secondary strake 11, in the direction of the insulating barrier 20. This drop wall 41 is extended by an attachment wall 42 which extends parallel to the flat portion 12 of the secondary strake 11.

[0223] The hook wall 42 extends from the drop wall 41, perpendicular to the drop wall 41, and is oriented opposite to the flat portion 12 of the strake 11. The flat portion 12, the drop wall 41 and the hook wall 42 thus have a step profile.

[0224] In all variants represented here, the attachment wall 42 extends continuously along the entire longitudinal edge of the strake 11.

[0225] The drop wall 41 extends into the portion of the groove 26 that opens onto the inner surface 21 of the insulating barrier 20, while the grip wall 42 of the grip element 40 extends into the portion of the groove 26 formed by the bar of the inverted T. Thus, the grip wall 42 has a gripping surface 42A oriented towards the interior of the tank, which bears against an inner face 26A of the groove 26 to lock the secondary strake 11 in the direction of the tank wall thickness.

[0226] The secondary strake 11 nevertheless remains free to slide in the groove 26, along the longitudinal direction D.

[0227] To insert the first longitudinal edge 14A into the groove 26, a pivoting movement of the secondary strake 11 is performed, as shown in [Fig. 4] by arrow F. The insertion of the hook wall 42 into the groove 26 of the insulating barrier that receives this hook wall 42 is achieved by pivoting the strake around an axis parallel to the longitudinal direction of the strake. This is possible thanks to the stepped profile of the flat portion 12, the drop wall 41, and the hook wall 42 of the strake.

[0228] In this first variant, the hooking element 40 cooperates in retention with the inner face 26A of a wall of the groove 26.

[0229] According to a second variant shown in [Fig.6], the hooking element 40 cooperates in retention with a retention element 60 brought into the groove 26.

[0230] According to this second variant, the configuration of the strut 11 and the insulating blocks 22 is similar to that of the first variant. Instead of having an inverted T-shaped profile as in the first variant described above, the groove 126 here has a generally rectangular cross-section. The groove 126 is formed longitudinally in the cover plates 24 of the insulating blocks 22 and presents a base in which one longitudinal part is deeper than another longitudinal part. The longitudinal lateral walls of groove 126 are straight.

[0231] The groove 126 receives a retaining element inserted into the groove, for example a parallelepiped-shaped block 60. This block 60 is housed in the groove 126. It has dimensions that create an L-shaped space 126A between the block 60 and the inner faces of the groove 126. More precisely, the space 126A is delimited between one of the longitudinal lateral walls of the groove 126 and the block 60, and between the deepest longitudinal portion of the bottom and the block 60.

[0232] The first longitudinal edge 14A of the strake 11 is introduced into the groove 126 by a pivoting or translational movement in the thickness direction of the tank wall, so as to house the hook wall 42 of the first longitudinal edge 14A of the secondary strake in the longitudinal part of the bottom of the groove 126 which has a greater depth than the other longitudinal part of the bottom.

[0233] The retaining element is fixed in the groove 126, for example by screws 63 screwed through the retaining element 60 and the cover plate 24 and / or by gluing.

[0234] The first longitudinal edge 14A forming the attachment element 40 of the secondary strake is identical to that of the first variant described above.

[0235] The falling wall 41 and the hooking wall 42 of the hooking element 40 extend into the space 126A provided by the cleat 60 in the groove 126. Thus, the hooking wall 42 has a hooking surface 42A oriented towards the inside of the tank, which bears against a face 61 of the cleat 60 oriented towards the load-bearing wall 1, 2 to lock the strake 11 in the direction of the thickness of the tank wall.

[0236] According to a third variant shown in [Fig. 7], the configuration of the strake 11 and the insulating blocks 22 is similar to that of the first variant. Instead of having an inverted T-shaped profile as in the first variant described above, the groove 226 has an L-shaped cross-section. Preferably, the opening of the groove 226 on the inner surface 21 of the insulating barrier 20 is sufficiently wide to allow the passage of the retaining wall 42 without pivoting. The first longitudinal edge 14A of the strake 11 is then inserted into the groove 226 by a translational movement in the thickness direction of the tank wall, and then by a sliding movement in a plane parallel to the inner surface 21 of the insulating barrier 20, which engages the retaining wall 42 of the first longitudinal edge 14A of the secondary strake under a return of the cover plate 24 formed by the groove.The attachment surface 42A bears against a complementary face of this return. In the example of [Fig.7], the strake is further blocked in the longitudinal direction D by the use of additional fixing elements such as screws 64 passing through the return of the cover plate and the attachment wall 42.

[0237] According to a fourth variant shown in [Fig. 8], each secondary strut 11 has a width equivalent to the width of an insulating block 22 of the secondary insulating barrier 20. Each secondary strut 11 is placed on an insulating block 22 and completely covers it. Part of the hooking element 40 is received in a groove 326 formed in a lateral face of the insulating blocks 22 forming the insulating barrier 20.

[0238] More specifically, here, the cover plate 24 has a groove 326 formed in a longitudinal lateral face of the cover plate 24. This groove 326 therefore opens onto the space 28 delimited by two adjacent insulating blocks.

[0239] The first longitudinal edge 14A of the strake 11 has a C-shaped hook, the free end of which is inserted into the groove 326. For this purpose, the cover plate 24 is placed on the insulating block 20 so that the free end of the first longitudinal edge 14A of the strake is opposite the groove 326, then the strake is slid onto the insulating block to insert the free end of the first longitudinal edge 14A of the strake into the groove 326, as shown in the successive steps of [Fig.8].

[0240] According to a fifth variant shown in [Fig. 9], each secondary strut 11 has a width equivalent to the width of an insulating block 22 of the secondary insulating barrier 20. Each secondary strut 11 is placed on an insulating block 22 and completely covers it. The hooking element 40 is received in the space 28 separating two adjacent insulating blocks 20.

[0241] In this fifth variant, the shape of the hooking element 40 is slightly different. As before, the first longitudinal edge 14A forming the hooking element 40 includes a longitudinal drop wall 141 which extends from the flat portion 12 of the strake 11 and is folded at a right angle to the flat portion 12 of the strake 11, in the direction of the insulating barrier 20. This drop wall 141 is extended by a hooking wall 142 which extends obliquely from the drop wall 141, in the direction of the interior of the tank.

[0242] A supplementary fastening element 90 is further provided, extending into the space 28 separating the two adjacent insulating blocks 20. This supplementary fastening element 90 is in the form of a profiled metal clip, the base 91 of which is housed in a slot 28A extending from the space 28 separating the two insulating blocks, along a lower face 24A of the cover plate 24 oriented towards the load-bearing wall 1, 2. From this base 91, the clip comprises a portion having a cross-section shaped like a hook 92, comprising a band rising at a right angle to the base 91, against the longitudinal lateral face of the cover plate 24, towards the interior of the tank, and a supplementary fastening band extending obliquely outwards from the tank, parallel to the hooking wall 142 of the hooking element 40. The hooking element cooperates in retention with the hook 92 to lock the strake in the thickness direction of the tank wall.

[0243] According to the first, second, third, fourth, fifth and sixth variants described above, the hooking element 40 extends continuously along the first longitudinal edge 14A of the strake 11. It constitutes the first longitudinal edge 14A of the strake 11.

[0244] According to other variants, shown in figures 16 to 18, a hooking element 240 is attached to the first longitudinal edge 14A of the strake 11,11', preferably the secondary strake 11. Preferably, the hooking element 240 is welded to the first longitudinal edge 14A of the strake 11,11'.

[0245] The attachment element 240 comprises a planar connecting portion 244 which extends parallel to the planar portion 12 of the strake 11, along the entire length of the first longitudinal edge 14A of the strake 11 and is fixed to the first longitudinal edge 14A of the strake 11. This connecting portion 244 is extended by a drop wall 241 which extends perpendicularly to the connecting portion 244 along the entire length of the connecting portion 244. This drop wall 241 is extended by an attachment portion 242 which extends parallel to the connecting portion 244 of the attachment element 240, therefore parallel to the planar portion 12 of the strake 11, along the entire length of the drop wall 241.

[0246] The hooking part 241 extends opposite the connecting part 244, towards the outside of the strake 11.

[0247] For example, according to a seventh variant, shown in [Fig. 16], the first longitudinal edge 14A of the strake 11 is straight and flat, in line with the flat portion 12 of the strake 11 and in the same plane as the latter.

[0248] The connecting part 244 of the attachment element 240 is attached to the inner face 121 of the strake 22 oriented towards the inside of the tank and fixed to the longitudinal edge of the strake, for example by welding.

[0249] The hooking element 240 is used similarly to the hooking element 40 described with reference to the first embodiment. The drop wall 241 of the hooking element 240 extends into the portion of the groove 26 that opens onto the inner surface 21 of the insulating barrier 20, while the hooking wall 242 of the hooking element 240 extends into the portion of the groove 26 formed by the bar of the inverted T. Thus, the hooking wall 242 has a hooking surface 242A oriented towards the interior of the tank, which bears against an inner face 26A of the groove 26 to lock the secondary strut 11 in the direction of the tank wall thickness.

[0250] The secondary strake 11 nevertheless remains free to slide in the groove 26, along the longitudinal direction D.

[0251] To insert the first longitudinal edge 14A into the groove 26, a pivoting movement of the secondary strake 11 is carried out.

[0252] It is also possible, as in the eighth and ninth variants shown in Figures 16 and 17, for the connecting portion 244 of the attachment element 240 to be attached and fixed to an outer face 122 of the strake 11 facing outwards from the tank. In this case, a recess 29 is provided in the cover plate 24 adapted to receive the connecting portion 244 of the attachment element 240, slightly recessed from the inner surface 21 of the cover plate 24, so that the connecting portion of the attachment element 240 is flush with the inner surface 21 of the cover plate 24.

[0253] In the eighth embodiment, shown in [Fig. 17], the strakes 11 have first and second longitudinal edges 14A, 14B that are straight and flat, extending in the same plane as the flat portion 12 of the strake 11. The first and second longitudinal edges 14A, 14B of two adjacent strakes 11 are each fixed to the connecting portion 244 of the attachment element 240. They are, for example, welded to the connecting portion 244. Either the two longitudinal edges of the adjacent strakes are welded edge to edge and simultaneously to the connecting portion 244, or the two longitudinal edges 14A, 14B of the adjacent strakes 11 are welded separately to different portions of the connecting portion 244.

[0254] In the ninth embodiment of [Fig. 18], the first longitudinal edge 14A of each strake 11 is straight and flat. It extends in the same plane as the flat portion 12 of the strake 11. This first longitudinal edge 14A is fixed to the connecting part 244 of the attachment element 240.

[0255] Whatever variant is considered, with the exception of the eighth variant described above, along its second longitudinal edge 14B, the secondary strake 11 has a rim 43 (figures 5, 6, 7 and 9) extending outward from the flat portion 12 of the secondary strake 11, towards the interior of the tank, i.e. opposite the falling wall 41; 241 of the attachment element 40; 240.

[0256] The rim 43 covers a portion 12A of the flat portion 12 of an adjacent secondary strake 11 in the first, second, third, fourth, fifth, and sixth variants. It covers the first longitudinal edge 14A of the adjacent strake 11, which forms part of the flat portion of the strake 11, in the seventh and ninth variants.

[0257] Figures 5, 6, 7 and 9 show the rim 43 of the second longitudinal edge 14B of the adjacent secondary strake 11 partially covering the part 12A of the flat portion 12 of the secondary strake 11, the first longitudinal edge 14A of which is described above and represented. Figures 16 and 18 show the rim 43 of the second longitudinal edge 14B of the adjacent secondary strake 11 covering the first longitudinal edge 14A of the adjacent strake 11 which forms part of the flat part 12 of the strake 11 in the seventh and ninth variants.

[0258] The part 12A of the secondary strake 11 covered by the rim 43 formed by the second longitudinal edge 14B of the adjacent secondary strake 11 extends along the first longitudinal edge 14A of the secondary strake 11, immediately in close proximity to the drop wall 41; 241 of the attachment element 40.240.

[0259] The rim 43 is arranged so that the flat portion 12 of the adjacent secondary strake 11 extends in the same plane as the flat portion 12 of the secondary strake 11.

[0260] The flange 43 is continuously and tightly welded to the part 12A of the covered flat portion 12. The flange 43 is, for example, lap welded.

[0261] The various assembly and joining solutions for secondary strakes 11 without raised edges are described above in the case of forming a secondary watertight membrane. Of course, the same solutions can be used to assemble primary strakes 11' without raised edges to form a primary watertight membrane 10'.

[0262] In addition, it is possible to consider that the attachment element of the seventh, eighth and ninth variants described above have a geometry such that its profile is similar to that of the attachment element described in the fifth and sixth variant.

[0263] In the embodiments described herein, the width of the strakes 11, 11'; 411 of the waterproof membrane 10, 10' is equal to the width of the insulating blocks 22, 22' of the corresponding insulating barrier 20, 20'. Alternatively, the width of the strakes of the waterproof membrane may be different, for example, equal to half the width of the insulating blocks of the corresponding insulating barrier.

[0264] In particular, a tank can be envisaged comprising a secondary watertight membrane similar to that of the first embodiment described above and a primary membrane similar to the primary membrane described in the third embodiment, having raised edges and without longitudinal corrugations. In this case, the secondary membrane is preferably made of an iron and manganese alloy having a coefficient of expansion less than or equal to 9 x 10⁶ K⁻¹ and the primary membrane is preferably made of an iron and nickel alloy having a coefficient of expansion typically less than or equal to 2 x 10⁶ K⁻¹, for example in the alloy known as "Invar".

[0265] The tank wall may comprise only one sealed membrane and one insulating barrier.

[0266] The case described here is one in which the primary lateral wing receiving band has corrugated portions arranged in line with the primary longitudinal corrugations of the primary strakes to terminate the primary longitudinal corrugations at a distance from the primary watertight bonding zone. Alternatively, the primary lateral wing receiving band may have corrugated portions arranged in line with the longitudinal upturned edges of the primary strakes to terminate the upturned edges at a distance from the primary watertight bonding zone.

[0267] With reference to [Fig. 15], a cutaway view of an LNG carrier 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the vessel. The wall of the tank 71 comprises a primary watertight barrier intended to be in contact with the LNG contained in the tank, a secondary watertight barrier arranged between the primary watertight barrier and the double hull 72 of the vessel, and two insulating barriers arranged respectively between the primary watertight barrier and the secondary watertight barrier and between the secondary watertight barrier and the double hull 72.

[0268] In a manner known per se, loading / unloading pipelines 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a marine or port terminal or to an LNG bunker ship to transfer an LNG cargo to or from the tank 71.

[0269] Figure 15 shows an example of a marine terminal comprising a loading and unloading berth 75, a subsea pipeline 76 and an onshore facility 77. The loading and unloading berth 75 is a fixed offshore facility comprising a movable arm 74 and a tower 78 which supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipelines 73. The steerable movable arm 74 is suitable for all LNG carrier sizes. An unshown connecting pipeline extends inside tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore facility 77. This facility includes liquefied gas storage tanks 80 and connecting pipelines 81 linked by the subsea pipeline 76 to the loading or unloading station 75.The subsea pipeline 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore facility 77 over a long distance, for example 5 km, which allows the LNG carrier 70 to be kept a long distance from the coast during loading and unloading operations.

[0270] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the land installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0271] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0272] The invention applies to ship tanks 71 and also to land-based reservoirs and port structures.

[0273] The use of the verb "comprise", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

[0274] In claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Demands

1. A watertight and thermally insulating tank, integrated into a load-bearing structure (4) comprising a load-bearing wall (1, 2), the tank comprising a tank wall fixed to the load-bearing wall (1, 2) in which the tank wall comprises at least one watertight membrane (10, 10') and an insulating barrier (20, 20') arranged between the watertight membrane (10, 10') and the load-bearing wall (1, 2), in which the watertight membrane (10, 10') comprises a plurality of parallel strakes (11, 11'; 411), a strake being in the form of a metal strip elongated along a longitudinal direction (D), and having a uniform profile along the longitudinal direction (D), each strake comprising a flat portion (12, 12'; 412) resting on an internal surface (21, 21') of the insulating barrier (20, 20') and at least one longitudinal undulation (13, 13' ; 413) projecting towards the interior of the vat relative to the flat portion (12, 12' ; 412) of the strake (11, 11' ;411), said or each longitudinal corrugation (13, 13'; 413) being spaced from the longitudinal edges (14A, 14B, 14A', 14B'; 414A, 414B) of the strake (11, 11'; 411), each longitudinal corrugation (13, 13'; 413) extending along the longitudinal direction (D) of the strake (11, 11'; 411), the strakes (11, 11'; 411) being juxtaposed and welded together watertight at said longitudinal edges (14A, 14B, 14A', 14B'; 414A, 414B), in which said or each corrugation (13, 13'; 413) comprises: - two curved parts concave (131) connected to an element (125A, 125B) of the flat portion (12) of the strake (11, 11', 411), - a central flat part (132) at the top of the undulation (13, 13' ; 413) and - two convex curved parts (133) each connecting one end of the central flat part (132) to a said concave curved part (131).;

2. A sealed and thermally insulating tank according to claim 1, wherein each concave curved part (131) of said or each corrugation (13, 13'; 413) is directly connected to one of the two convex curved parts (133) of the corrugation (13, 13'; 413).

3. A watertight and thermally insulating tank according to claim 1, wherein each concave curved portion (131) of said or each undulation (13, 13' ; 413) is connected to one of the two convex curved parts (133) of the undulation by a lateral flat part (134) of the undulation (13, 13' ; 413).

4. A sealed and thermally insulating tank according to any one of claims 1 to 3, wherein a concave curved part (131) and / or a convex curved part (133) of said or each undulation (13, 13'; 413) has, along a plane perpendicular (PP) to said longitudinal direction (D), a circular arc section whose radius of curvature (RI, R2; RI', R2') is between 5 and 15 millimeters.

5. A sealed and thermally insulating tank according to claim 4, wherein the circular arc section extends over an angle (A2, A3; A2', A3') between 10 and 80 degrees of arc.

6. A sealed and thermally insulating tank according to any one of claims 1 to 5, wherein the central flat part (132) and the concave curved parts (131) or the convex curved parts (133) of said or each corrugation (13, 13') extend into one another in such a way that the profile of said or each corrugation (13, 13') has a slope varying continuously in a plane perpendicular to the longitudinal direction (D).

7. A sealed and thermally insulating tank according to claim 3, wherein the central flat part (132), the lateral flat parts (134) and the concave curved parts (131) or the convex curved parts (133) of said or each corrugation (13, 13') extend into one another in such a way that the profile of said or each corrugation (13, 13') has a slope varying continuously in a plane perpendicular (PP) to the longitudinal direction (D).

8. A sealed and thermally insulating tank according to any one of claims 1 to 7, wherein said or each corrugation (13, 13'; 413) extends laterally, in a direction perpendicular to the longitudinal direction (D), over a total width (DI; Dl') measured from one concave curved part (131) to the other concave curved part (131) of between 30 and 70 millimeters.

9. A watertight and thermally insulating tank according to any one of claims 1 to 8, wherein said or each corrugation (13, 13'; 413) extends vertically along a thickness direction (E) of the tank, over a total height (H; H') measured between the flat portion (12, 12'; 412) of the strake (11, 11'; 411) and the flat portion central (132) of the undulation (13, 13' ; 413) between 8 and 17 millimeters.

10. A sealed and thermally insulating tank according to any one of claims 1 to 9, wherein the central flat part (132) of said or each undulation (13, 13; 413) extends laterally, in a direction perpendicular to the longitudinal direction, over a width of between 4 and 30 millimeters.

11. A watertight and thermally insulating tank according to any one of claims 1 to 10, wherein: - said load-bearing wall (1, 2) is a first load-bearing wall (1) and the load-bearing structure (4) further comprises a second load-bearing wall (2), joining the first load-bearing wall (1) at an edge (3) of the load-bearing structure (4), - said tank wall is a first tank wall and the tank comprises a second tank wall fixed to the second load-bearing wall (2), - the tank comprises a metal corner beam (30; 330; 430) disposed parallel to the edge (3) of the load-bearing structure and anchored to the first and second load-bearing walls (1, 2), the corner beam (30; 330; 430) comprising a first lateral flange (31, 31'; 331; 431) parallel to the first load-bearing wall (1) and a second lateral flange (32; 332; 432) parallel to the second load-bearing wall (2), the two lateral wings (31, 32; 331, 332;431, 432) being linked to each other at the level of a watertight bonding zone (33; 333; 433), the first lateral wing (31, 31'; 331) of the corner beam (30; 330; 430) comprising a connecting part (31 A, 431 A,) belonging to the watertight bonding zone (33; 333; 433) and a receiving strip (34, 34'; 334; 434) welded to the connecting part (31 A; 431 A); the receiving strip extending from the bonding zone, away from the connecting part (31A; 431A), in which a distal portion (34A, 34A'; 334A; 434A) of the receiving strip is welded to an end portion (15, 15'; 415) of the strakes (11, 11'; 411) of the membrane of the first wall (1) of the tank, the receiving strip (34, 34'; 334; 434) of said first lateral wing (31, 31'; 331; 431) having corrugated parts (35, 35'; 335; 435) arranged in alignment with the longitudinal undulations (13, 13'; 413) of the strakes (11, 11';411) to finish the longitudinal undulations (13, 13' ; 413); said strakes (11, 11' ; 411 ) at a distance from the bond zone (33 ; 333 ; 433).

12. Watertight and thermally insulating tank according to claim 11, wherein at least one of the corrugated parts (35, 35'; 435) is made in one piece with said receiving strip (34, 34'; 434).

13. A watertight and thermally insulating tank according to claim 12, in which at least one of the corrugated parts (35, 35') is made by stamping.

14. A sealed and thermally insulating tank according to any one of claims 1 to 13, wherein at least one of the corrugated parts (335) comprises a piece attached to a flat part (334C) of the receiving strip (334) of the side wing (331, 332).

15. A watertight and thermally insulating tank according to any one of claims 1 to 14, wherein the corrugated part (35, 35'; 335; 435) has a shape adapted to cover the longitudinal end of a longitudinal corrugation (13, 13'; 413) and to extend it on the lateral wing (31, 31'; 431) in the direction of the connection zone (33; 433).

16. Watertight and thermally insulating tank according to any one of claims 1 to 15, wherein the insulating barrier (20,20') comprises insulating blocks (22, 22') and each strake (11, 11') comprises a longitudinal hooking element (40; 240) adapted to cooperate in retention with the insulating blocks (22, 22') of the insulating barrier (20, 20') to retain the strake (11, 11') in the direction of the thickness of the tank wall, while allowing movement of the strake along a longitudinal direction (D) of the strake.

17. A sealed and thermally insulating tank according to claim 16, in which the hooking element (40; 240) is received in a groove (26; 126; 226) formed in the insulating barrier (20, 20') and opening onto said internal surface (21, 21').

18. A sealed and thermally insulating tank according to claim 17, in which the hooking element (40) cooperates in retention with a surface of a wall of the groove (226) or with a retaining element (60) brought into the groove (126).

19. A watertight and thermally insulating tank according to any one of claims 1 to 18, wherein at least one of the strakes (11, 11' ; 411) includes one or two longitudinal undulations (13, 13' ; 413).

20. A watertight and thermally insulating tank according to any one of claims 1 to 19, wherein the watertight membrane (10) constitutes a secondary watertight membrane and is surmounted by a primary insulating barrier (20') and a primary watertight membrane (10').

21. A watertight and thermally insulating tank according to claim 20, wherein the primary watertight membrane (10') comprises a plurality of primary strakes (11'), a primary strake (11') comprising a flat portion (12') resting on an internal surface (21') of the primary insulating barrier (20') and at least one primary longitudinal portion (13') projecting into the interior of the tank relative to the flat portion (12') of the primary strake (11'), the primary strakes being juxtaposed and welded together watertight at said longitudinal edges, the metal corner beam (30) further comprising a first primary lateral flange (31') parallel to the first load-bearing wall (1) and a second primary lateral flange (32') parallel to the second load-bearing wall (2), the two primary lateral flanges being connected to each other at a watertight bonding zone (33). primary,at least one of the first and second primary lateral wings of the corner beam (30) having a receiving strip (34, 34') extending from the primary watertight bonding zone (33), away from the primary watertight bonding zone, wherein a distal portion (34A') of the receiving strip (34') of the primary lateral wings (31', 32') of the corner beam (30) is welded to an end portion (15') of the primary strakes (11') of the primary watertight membrane (10'), the receiving strip (34') of the primary lateral wings having corrugated portions (35') arranged in alignment with the primary longitudinal portions (13') of the primary strakes to terminate the primary longitudinal portions at a distance from the primary watertight bonding zone (33).

22. A watertight and thermally insulating tank according to any one of claims 1 to 21, wherein the watertight membrane (10') constitutes a primary watertight membrane and the insulating barrier (20') constitutes a primary insulating barrier, and the tank wall comprises a secondary insulating barrier (20) and a watertight membrane (10) secondary layers are positioned between the primary insulating barrier and the load-bearing structure.

23. A watertight and thermally insulating tank according to any one of the preceding claims, in which the strakes (11, 11') are made of an iron and manganese or nickel alloy having a coefficient of expansion less than or equal to 9.106 K'.

24. Watertight and thermally insulating tank according to any one of the preceding claims, wherein the width of the strakes (11, 11') of the watertight membrane (10, 10') is equal to the width of the insulating blocks (22, 22') of the corresponding insulating barrier or equal to half the width of the insulating blocks of the corresponding insulating barrier.

25. Vessel (70) for the transport of a fluid, the vessel comprising a double hull (72) and a tank (71) according to any one of claims 1 to 24 disposed in the double hull (72).

26. Transfer system for a fluid, the system comprising a vessel (70) according to claim 25, insulated pipes (73, 79, 76, 81) arranged to connect the vessel's tank (71) to a floating or land-based storage facility (77) and a pump for conveying a fluid through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

27. ​​A method of loading or unloading a ship (70) according to claim 25, wherein a fluid is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or land-based storage facility (77) to or from the ship's tank (71).

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