EP2906867B1 - Fluidtight and thermally insulated tank comprising a metal membrane that is corrugated in orthogonal folds - Google Patents

Description

The present invention relates to a sealed and thermally insulating tank; in particular, the present invention relates to tanks intended to contain cold liquids, for example tanks for the storage and / or transport by sea of liquefied gases.

Sealed and thermally insulating tanks can be used in different industries to store hot or cold products. For example, in the field of energy, liquefied natural gas (LNG) is a liquid that can be stored at atmospheric pressure at about -163 ° C in terrestrial storage tanks or in tanks on board floating structures.

Such a tank is for example described in the document FR-A-2724623 , and in the document WO2008 / 147003 .

• une barrière d'isolation thermique retenue sur la paroi porteuse et constituée de blocs d'isolation en forme de parallélépipèdes rectangles, juxtaposés selon des rangées parallèles et séparés les uns des autres par des interstices,
• une barrière d'étanchéité supportée par la barrière d'isolation thermique, ladite barrière d'étanchéité comportant une membrane métallique constituée de tôles métalliques soudées les unes aux autres de manière étanche,
• chaque bloc d'isolation d'une barrière d'isolation thermique portant, sur sa face opposée à la paroi porteuse, au moins deux bandes de liaison métalliques sensiblement orthogonales, disposées parallèlement aux côtés du bloc d'isolation, bandes sur lesquelles sont soudées les tôles de la membrane métallique supportée par ledit bloc d'isolation, lesdites bandes de liaison étant solidaires du bloc d'isolation qui les porte,
• une pluralité des tôles de la membrane métallique comportant chacune au moins deux plis orthogonaux parallèles aux côtés des blocs d'isolation thermique, lesdits plis étant insérés dans les interstices ménagés entre les blocs d'isolation.

According to one embodiment, the invention provides a sealed and thermally insulating tank integrated into a structure which comprises a supporting wall, said tank comprising a tank wall fixed to said supporting wall, the tank wall comprising:

• a thermal insulation barrier retained on the load-bearing wall and made up of insulation blocks in the form of rectangular parallelepipeds, juxtaposed in parallel rows and separated from each other by interstices,
• a sealing barrier supported by the thermal insulation barrier, said sealing barrier comprising a metal membrane made of metal sheets welded to each other in a sealed manner,
• each insulation block of a thermal insulation barrier bearing, on its face opposite the load-bearing wall, at least two substantially orthogonal metal connecting strips, arranged parallel to the sides of the insulation block, strips to which the strips are welded sheets of the metal membrane supported by said insulation block, said connecting strips being integral with the insulation block which carries them,
• a plurality of sheets of the metal membrane each comprising at least two orthogonal folds parallel to the sides of the thermal insulation blocks, said folds being inserted into the interstices formed between the insulation blocks.

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

According to one embodiment, the metal sheets of the membrane each comprise at least two orthogonal folds parallel to the sides of the thermal insulation blocks, inserted in the interstices formed between the insulation blocks.

According to one embodiment, the vessel wall comprises a primary element and a secondary element arranged between the bearing wall and the primary element, each of the primary and secondary elements including a thermal insulation barrier made up of shaped insulation blocks. rectangular parallelepipeds, juxtaposed in parallel rows and a sealing barrier arranged on the thermal insulation barrier, the thermal insulation barrier of the secondary element being secured to the bearing wall, the thermal insulation barrier of the 'primary element being secured by hooking means linked to the thermal insulation barrier of the secondary element.

According to one embodiment, the sealing barrier of the secondary element consists of the metal membrane comprising a plurality of sheets each comprising at least two orthogonal folds parallel to the sides of the thermal insulation blocks, and inserted into the interstices formed between the insulation blocks of the secondary element.

According to one embodiment, the sheets of the metal membrane of the secondary element are made from an alloy of ter with nickel or manganese and having an expansion coefficient less than or equal to 7.10 ^-6 K ^-1 .

According to one embodiment, the folds of the metal sheets of the secondary sealing barrier are inserted into the interstices between the insulation blocks of the thermal insulation barrier of the secondary element.

According to one embodiment, the folds of the metal sheets of the primary sealing barrier are inserted into the interstices between the insulation blocks of the thermal insulation barrier of the primary element. According to other embodiments, the primary membrane may have a different design from the secondary membrane, for example with protruding folds towards the interior of the vessel. In other words, the sealing barrier of the primary element consists of metal sheets welded to each other in a leaktight manner and comprising folds directed towards the interior of the tank.

According to one embodiment, an insulating block of the thermal insulation barrier comprises a base plate on which is placed a layer of foam, in particular of polyurethane, the base plate protruding from the foam. The plates can be made of plywood. The secondary element is held in abutment on the bearing wall by means of fasteners welded to the bearing wall and cooperating with the projecting areas of the plates of the insulation block, possibly with interposition of resin strands to catch up with local imperfections in the load-bearing wall.

According to one embodiment, an insulating block for the thermal insulation barrier of the secondary element is held on the bearing wall by gluing.

Numerous arrangements of the connecting strips on the insulation blocks are possible, in particular as regards the position and the number of the connecting strips on an insulation block. In this regard, all insulation blocks are not necessarily identical.

According to one embodiment, the connecting strips of each insulation block of the thermal insulation barrier of the secondary element carries two connecting strips which are arranged along the two axes of symmetry of the rectangle defined by a large face of said insulation block.

According to one embodiment, the connecting strips of each insulation block of the thermal insulation barrier of the primary element are arranged in the vicinity of the edges of a large face of said insulation block.

According to one embodiment, an insulation block comprises three connecting strips arranged on the cover plate.

According to one embodiment, the connecting strips of an insulation block are housed in recesses made in the plate or the layer of foam which carries it so as not to constitute an extra thickness on the corresponding face of the insulation block.

According to one embodiment, a connecting strip of an insulation block is fixed in its recess by screwing, stapling, riveting or gluing.

According to one embodiment, the means for fastening the thermal insulation barrier of the primary element comprise a continuous metal plate arranged at the intersection of the two bands. connecting each insulation block of the secondary element, and a projecting member passing through the level of the sealing barrier of the secondary element without rising to the level of the sealing barrier of the primary element.

According to one embodiment, the adjacent metal sheets of the sealing barriers of the primary and secondary elements are overlapped welded to the right of the connecting strips carried respectively by the thermal insulation barriers of the primary and secondary elements.

According to one embodiment, the projecting members are studs, the base of which is fixed on the continuous metal plate of the insulating block of the secondary element, an intermediate piece being interposed between, on the one hand, a nut cooperating with the thread provided at the free end of the stud and, on the other hand, the protruding parts of the plates of the insulation blocks of the thermal insulation barrier of the primary element. The base of the studs is fixed by welding and / or screwing to the continuous metal plate of the insulation block of the secondary element.

According to one embodiment, the sheets of the metal membranes which constitute the sealing barrier are rectangular and each have two folds arranged along the axes of symmetry of the rectangle formed by their edges.

According to one embodiment, the two folds of a sheet and the sealing barrier of the primary element intersect at the center of the rectangular sheet.

According to one embodiment, one of the folds of a sheet is continuous and the other is interrupted in its central part.

According to one embodiment, sheets of a first type have a continuous fold on their major axis.

According to one embodiment, sheets of a second type have a discontinuous fold on their major axis.

According to one embodiment, on a tank wall the sheets of the first and second types are regularly alternated so that a sheet of one of the types is always adjacent to a sheet of the other type.

According to one embodiment, each insulation block of the thermal insulation barrier comprises two series of orthogonal slots, each of said series comprising slots arranged parallel to two opposite sides of the insulation block, and the sheets of the metal membrane. each comprise two series of additional folds, each of said series of additional folds comprising folds, orthogonal to the folds of the other series, parallel to one of the two folds inserted in the interstices, and inserted into the slots of one of the series of slots in the insulation block.

According to another embodiment, the metal membrane comprises a second plurality of sheets, each of the sheets of the second plurality comprising a single fold parallel to two opposite sides of the insulation blocks, said fold being inserted in a gap formed between two blocks. insulation.

According to another embodiment, each insulation block of the thermal insulation barrier has a slot parallel to two opposite sides of the insulation blocks and in which the metal membrane comprises a second plurality of sheets, each of the sheets of the insulation block. second plurality comprising a ply inserted in a slot formed in an insulation block and a ply inserted in a gap formed between two insulation blocks.

Such a tank can be part of an onshore storage installation, for example to store LNG or be installed in a storage facility. floating, coastal or deep-water structure, in particular an LNG vessel, a floating storage and regasification unit (FSRU), a floating production and remote storage unit (FPSO) and others.

According to one embodiment, a ship for transporting a cold liquid product comprises a double hull and a said tank arranged in the double hull.

According to one embodiment, the invention also provides a method of loading or unloading such a vessel, in which a cold liquid product is conveyed through isolated pipes from or to a floating or land storage installation to or from the vessel. vessel tank.

According to one embodiment, the invention also provides a transfer system for a cold liquid product, the system comprising the aforementioned vessel, insulated pipes arranged so as to connect the tank installed in the hull of the vessel to a floating storage installation. or terrestrial and a pump for driving a flow of cold liquid product through the insulated pipelines from or towards the floating or terrestrial storage facility to or from the vessel of the vessel.

An idea underlying the invention is to provide a waterproof and insulating multilayer structure which is easy to produce over large surfaces. Certain aspects of the invention start from the idea of producing insulation blocks the geometry of which is simple and the manufacture inexpensive. Certain aspects of the invention start from the idea of providing a waterproof membrane, in particular a secondary membrane made of sheet steel with a low coefficient of expansion, for example Invar® or other, of small thickness, in particular less than or equal to 0.7. mm, thus making it possible to obtain a low stiffness allowing anchoring at the edges of the tank wall using relatively compact anchoring means.

The invention will be better understood and other aims, details, characteristics and advantages thereof will emerge more clearly during the following description of several particular embodiments of the invention, given solely by way of demonstration and without limitation, with reference to the accompanying drawings.

• La figure 1 représente schématiquement, en perspective, un assemblage de différents organes constituant une cuve étanche et thermiquement isolante selon l'invention : cette vue générale comporte des parties arrachées pour permettre de voir les barrières d'isolation thermique et d'étanchéité des éléments secondaire et primaire de la paroi de cuve ;
• -la figure 2 représente schématiquement une coupe d'une paroi de cuve selon l'invention, dont la barrière d'étanchéité primaire comporte des plis saillants du côté opposé à la paroi porteuse ;
• -la figure 3 représente, en perspective, un bloc d'isolation de la barrière d'isolation thermique de l'élément secondaire de paroi de la cuve de la figure 1, ledit bloc comportant, dans sa zone centrale, un moyen d'accrochage des blocs d'isolation de la barrière d'isolation thermique de l'élément primaire de la paroi de la cuve ;
• -la figure 4 représente, en perspective, un bloc d'isolation de la barrière d'isolation thermique de l'élément primaire de la paroi de cuve de la figure 1 ;
• -la figure 5 représente, en perspective écorchée, les parties constitutives des barrières d'isolation thermique et d'étanchéité des éléments primaire et secondaire d'une paroi de cuve selon l'invention comportant, dans sa barrière d'étanchéité de l'élément primaire, des plis saillants vers l'intérieur de la cuve comme représenté sur la figure 2, ladite figure 5 montrant en détail la réalisation d'un moyen d'accrochage de la barrière isolante primaire sur une bande de liaison de la barrière isolante secondaire ;
• -la figure 6 représente une vue analogue à la figure 5, dans laquelle deux parties d'un moyen d'accrochage sont représentées désolidarisées, en perspective éclatée ;
• -la figure 7 représente schématiquement en coupe un moyen d'accrochage selon un autre mode de réalisation que celui des figures 5 et 6 ;
• -la figure 8 représente une vue de dessus en plan du moyen d'accrochage de la figure 7 ;
• -la figure 9 représente un schéma d'assemblage, dans une paroi de cuve, des tôles constitutives d'une barrière d'étanchéité, les tôles étant d'un premier et d'un deuxième type, pour que la souplesse de la membrane métallique de la barrière d'étanchéité soit relativement uniforme ;
• -la figure 10 représente un schéma d'assemblage analogue à celui de la figure 9, pour une variante de réalisation dans laquelle les plis des tôles métalliques de la barrière d'étanchéité qui sont disposés selon une première direction soient sensiblement alignés d'une tôle de la paroi de cuve à une tôle adjacente, alors que dans la direction orthogonale à la première, les plis sont interrompus pour éviter un croisement de plis ;
• -la figure 11 représente, en perspective schématique, un tronçon de cuve polyédrique réalisé dans un navire transporteur de GNL utilisant la membrane d'étanchéité représentée sur la figure 10, ce qui permet d'améliorer la souplesse de la membrane d'étanchéité pour des déformations de l'axe du navire au cours d'un transport maritime ;
• -la figure 12 représente schématiquement deux autres variantes de tôles métalliques utilisables pour former une membrane d'étanchéité ;
• -la figure 13 est une représentation schématique écorchée d'une cuve de navire méthanier et d'un terminal de chargement/déchargement de cette cuve ;
• -les figures 14 à 16 représentent schématiquement encore d'autres variantes de tôles métalliques utilisables pour former une membrane d'étanchéité ;
• -la figure 17 représente schématiquement dix-sept modes de réalisation de tôles métalliques plissées utilisables pour former une membrane d'étanchéité ;
• -les figures 18 à 23 représentent schématiquement différents agencements des tôles métalliques plissées de la figure 17 pouvant être répétés de manière périodique pour réaliser des membranes d'étanchéité.
• - la figure 24 représente, en perspective, un bloc d'isolation de la barrière d'isolation thermique de l'élément secondaire, selon un autre mode de réalisation.
• - la figure 25 illustre en perspective les barrières d'isolation thermique et d'étanchéité de l'élément secondaire selon le mode de réalisation de la figure 25, la barrière d'étanchéité étant représentée partiellement arrachée.
• - la figure 26 est une représentation une coupe des barrières d'isolation thermique et d'étanchéité de l'élément secondaire selon le mode de réalisation des figures 24 et 25.
• - la figure 27 illustre un schéma d'assemblage, dans une paroi de cuve, des tôles constitutives d'une barrière d'étanchéité secondaire, selon un autre mode de réalisation.
• - la figure 28 illustre un schéma d'assemblage, dans une paroi de cuves, de tôles constitutives d'une barrière d'étanchéité secondaire, selon encore un autre mode de réalisation.

On these drawings:

• The figure 1 schematically shows, in perspective, an assembly of different members constituting a sealed and thermally insulating tank according to the invention: this general view includes parts cut away to allow to see the thermal insulation and sealing barriers of the secondary and primary elements of the tank wall;
• -the figure 2 schematically shows a section of a tank wall according to the invention, the primary sealing barrier of which has protruding folds on the side opposite to the bearing wall;
• -the figure 3 shows, in perspective, an insulating block of the thermal insulation barrier of the secondary wall element of the tank of the figure 1 , said block comprising, in its central zone, a means for fastening the insulation blocks of the thermal insulation barrier of the primary element of the wall of the tank;
• -the figure 4 shows, in perspective, an insulating block of the thermal insulation barrier of the primary element of the vessel wall of the figure 1 ;
• -the figure 5 shows, in cutaway perspective, the constituent parts of the thermal insulation and sealing barriers of the primary and secondary elements of a tank wall according to the invention comprising, in its sealing barrier of the primary element, folds protruding towards the inside of the tank as shown in figure 2 , said figure 5 showing in detail the construction of a means for attaching the primary insulating barrier to a connecting strip of the secondary insulating barrier;
• -the figure 6 represents a view similar to the figure 5 , in which two parts of a fastening means are shown separated, in exploded perspective;
• -the figure 7 schematically shows in section a hooking means according to another embodiment than that of figures 5 and 6 ;
• -the figure 8 shows a top plan view of the attachment means of the figure 7 ;
• -the figure 9 shows an assembly diagram, in a tank wall, of the sheets constituting a sealing barrier, the sheets being of a first and a second type, so that the flexibility of the metal membrane of the barrier d the seal is relatively uniform;
• -the figure 10 represents an assembly diagram similar to that of the figure 9 , for an alternative embodiment in which the folds of the metal sheets of the sealing barrier which are arranged in a first direction are substantially aligned from a sheet of the tank wall to an adjacent sheet, while in the direction orthogonal to the first, the folds are interrupted to avoid a crossing of folds;
• -the figure 11 shows, in schematic perspective, a section of a polyhedral tank produced in an LNG carrier vessel using the waterproofing membrane shown in Figure figure 10 , which makes it possible to improve the flexibility of the waterproofing membrane for deformations of the axis of the ship during maritime transport;
• -the figure 12 schematically shows two other variants of metal sheets that can be used to form a waterproofing membrane;
• -the figure 13 is a cut-away schematic representation of an LNG vessel tank and a loading / unloading terminal for this tank;
• -the figures 14 to 16 schematically show yet other variants of metal sheets that can be used to form a waterproofing membrane;
• -the figure 17 schematically shows seventeen embodiments of pleated metal sheets that can be used to form a waterproofing membrane;
• -the figures 18 to 23 schematically show different arrangements of the pleated metal sheets of the figure 17 that can be repeated periodically to make waterproofing membranes.
• - the figure 24 shows, in perspective, an insulating block of the thermal insulation barrier of the secondary element, according to another embodiment.
• - the figure 25 illustrates in perspective the thermal insulation and sealing barriers of the secondary element according to the embodiment of the figure 25 , the sealing barrier being shown partially broken away.
• - the figure 26 is a representation in section of the thermal insulation and sealing barriers of the secondary element according to the embodiment of figures 24 and 25 .
• - the figure 27 illustrates an assembly diagram, in a tank wall, of the constituent sheets of a secondary sealing barrier, according to another embodiment.
• - the figure 28 illustrates an assembly diagram, in a tank wall, of sheets constituting a secondary sealing barrier, according to yet another embodiment.

In the different variants shown in the drawings, the components, which play the same role, have been designated by the same reference numbers even if their construction has been somewhat modified.

Referring to the drawings, it can be seen that 1 has designated as a whole an insulating block for the thermal insulation barrier of the secondary element of a vessel wall. This block has a length L and a width l, for example, respectively, 3 m and 1 m; it has the shape of a rectangular parallelepiped and it is made of polyurethane foam between two plywood sheets. One of the plates 2 a protrudes at the periphery of the foam and is intended to come to rest on the supporting wall 3 with the interposition of resin rods 4 allowing the local defects of the supporting wall 3 to be taken up. The other plate 2 b of the insulation block 1 comprises, along its two axes of symmetry, a metal connecting strip 6, which is placed in a recess 7 and which is fixed there by screws, rivets, staples or glue. In the zone of intersection of the bands 5 and 6, a continuous metal plate has been arranged, which supports, at the center of the crossing of the bands, a stud 8 projecting above the plate 2b . The plate 2 a is maintained on the supporting wall 3 by glueing by means of the resin rods 4 and 9 by studs welded to the supporting wall 3. It is ensured that between two adjacent blocks 1, be formed a gap 10, for example due to the presence of the protruding portions of the plate 2a, but optionally, by means of positioning pins.

If we now come back to the figure 1 , it can be seen that, starting from the uncovered secondary insulating block shown at the top and left of the figure and going in an oblique direction to the right and downwards, the perspective shows a secondary insulating block 1, which is partially covered a sheet 11 constituting a part of the secondary sealing barrier of the tank wall. This metal sheet 11 has a substantially rectangular shape and it comprises, along each of the two axes of symmetry of this rectangle, a fold 12 a , respectively 12 b . The folds 12 a and 12 b form reliefs arranged in the direction of the supporting wall 3 and they are housed in the interstices 10 of the secondary insulating barrier. The metal sheets 11 are made of invar®, the thermal expansion coefficient of which is typically between 1.5.10 ^-6 and 2.10 ^-6 K ^-1 . They have a thickness between about 0.7 mm and about 0.4 mm. Two adjacent sheets 11 are welded together to overlap, as will be described on the figures 5 and 6 . The retaining of the sheets 11 on the insulating blocks 1 is carried out with the strips 5 and 6 on which at least two edges of the sheets 11 are welded.

According to a preferred embodiment, the metal sheets 11 are made of a manganese-based alloy having a thermal expansion coefficient substantially equal to 7.10 ^-6 K ^-1 . Such an alloy is generally less expensive than alloys with a high nickel content such as invar®.

Referring again to the figure 1 , from the area where the metal sheets 11 of the sealing barrier of the secondary element of the vessel wall and moving obliquely to the right and downwards, it can be seen that a zone where the secondary sealing barrier is covered with an insulating block 13 of the thermal insulating barrier of the primary element of the vessel wall. The insulation block 13 is shown in detail on the figure 4 . It can be seen that this block has a general structure, which is similar to that of block 1, that is to say that it is a sandwich made up of a polyurethane foam between two plywood sheets. The base plate 13a, which rests on a metal sheet 11, has projecting parts 30 at the four corners. The fixing of these insulating blocks 13 is effected by means of the projecting parts 30 and the studs 8. On the upper face of the insulating block 13, there are two connecting strips 14 a , 14 b ; these connecting strips are metallic and arranged in recesses formed in the insulating block 13 to avoid any extra thickness on this insulating block. The two bands 14 a , 14 b are arranged parallel to the edges of the block 13 and they are fixed in their recesses as has been previously described for the bands 5 and 6.

Finally, the figure 1 shows, when moving from an element 13 obliquely downward and to the right, the placement of a metal sheet 15 constituting the sealing barrier of the primary element of the tank. This sheet 15 can be made of stainless steel with a thickness of approximately 1.2 mm; it comprises folds arranged along axes of symmetry of the rectangle that it constitutes, as has already been indicated for the metal sheets 11. These folds can be in relief on the side of the supporting wall 3, but they can also be in relief towards the inside of the tank; these folds have been designated by 16 a , 16 b . On the figure 2 , as well as on figures 5 and 6 , the folds 16 a , 16 b are directed towards the interior of the tank.

On the figures 5 and 6 , there is shown an embodiment in which the metal sheets 11 have a fold 12 a arranged inside a gap 10 and shown in dotted lines. The adjacent sheets of the secondary sealing barrier are lap welded, the weld area being designated 17. The weld is performed on the connecting strip 6, which also carries studs 18 welded at their base to the strip 6 and threaded at their upper end to cooperate with a tightening bolt 19. This tightening bolt is arranged at the bottom of a cup, the peripheral edge 20 rests in a recess 21 made on the plywood plate 13b, which limits the primary insulation barrier 13 towards the interior of the tank. On the primary insulating block is disposed a sheet 15, which has two lines of folds in relief towards the inside of the tank, the orthogonal folds meeting to form nodes; the sheets 15 are welded in a sealed manner and constitute the primary sealing barrier of the tank.

The connecting strip 6 is continuous at the level of the intersection with the connecting strip 5 so as to form a sealed zone 39 on which the corners of four sheets 11 can be welded around the stud 18. Thus, it is not necessary to perforate a sheet 11 to allow the stud 18 to pass in the direction of the primary element of the tank wall. Over the rest of their length, the connecting strips 5 and 6 are preferably formed of discontinuous juxtaposed segments, in order to limit the stresses resulting from thermal contraction, in particular the stresses in the welds with the sheets 11.

The figures 7 and 8 represent a variant of the attachment means, which make it possible to retain the insulation blocks 13 of the primary thermal insulating barrier resting against the metal membrane 11 of the secondary sealing barrier. This attachment means comprises a stud 18, the base of which is secured to the plywood plate 2b of the secondary thermal insulation block 1. Between the nut 22 and the projecting parts 30 of the plywood plates of the primary insulating blocks 13, an elastic spacer 23 has been interposed. This thus ensures the maintenance of the insulating blocks 13 of the primary thermal insulation barrier of the tank on the secondary element of the tank without the stud 18 coming to the level of the metal sheets 15 of the primary sealing barrier.

In the figures, in particular the figure 2 , relaxation slits 40 are shown through about half the thickness of the insulating blocks from the cover plate. These relaxation slots have the effect of subdividing the cover plates 2b and 13b into separate portions. However, such relaxation slots are not always necessary, depending on the properties of the material used to make the insulating blocks and the thermal stresses applied to them. In an embodiment not shown, an insulating block 1 or 13 does not have any relaxation slits, so that the cover plate 2b or 13b is continuous.

The figures 9 to 12 relate to the relative provisions of the folds that have been provided in the metal sheets of the secondary sealing barrier. These arrangements can also be used for the primary membrane.

The figure 9 represents the case where sheets are used comprising a continuous ply and a discontinuous ply orthogonal to the continuous ply. Two types of sheets 31 and 32 are arranged alternately. The edges of the sheets 31 and 32 are shown in broken lines. The folds are shown in solid lines. We see that we obtain a membrane characterized by the regularity of flexibility in both directions.

On the contrary, for the figure 10 , it is proposed to use only the type of sheet 32 that all the folds in one direction are continuous folds, while the folds in the other direction are discontinuous folds. On the figure 11 , we see that for a tank intended to equip a ship, we make sure that the discontinuous folds are parallel to the axis of the ship and the continuous folds, perpendicular to this axis because, during transport, the deformation of the hull of the ship occurs mainly by deformation of the axis of the ship in a vertical plane due to pitching.

The figure 12 shows two other sheets 51 and 52 which can be used for the realization of the sealing barrier at the level of the partitions transverse to the axis of the ship, as sketched on the figure 11 .

The figures 14 and 15 represent pleated sheets H and F which can be used instead of sheets 51 and 52 of the figure 11 to form the sealing barrier at the bulkheads transverse to the axis of the ship. In this case, wavy lines are obtained which are continuous across the width of the tank, and no longer in its height.

The figure 16 shows a pleated sheet E which can be used alone or in combination with the previous embodiments to form sealing barriers.

The figure 17 shows various pleated sheets A to R, including the examples given above and other examples, which can be used alone or can be combined in a number of ways to form sealing barriers.

The pleated sheets A to R each time have single folds or simple corrugations, which facilitates their assembly by watertight welds. They can be combined in multiple arrangements each time making it possible to obtain a certain elongation of the metal membrane in both directions of the plane. Preferred arrangements are shown in the figures 18 to 23 .

In a variant not shown, an alternation of two types of sheets is produced similar to the figures 22 and 23 , but this time with the plates H and 1 of the figure 17 .

In one embodiment illustrated in figures 24, 25 and 26 , the insulation block 1 of the thermal insulation barrier of the element secondary comprises two series of orthogonal slots 53 a , 53 b. Each series of slots 53 a, 53 b is parallel to two opposite sides of the insulation block 1. Each insulating block 1 here includes two slots 53a extending in its longitudinal direction and eight slots 53b extending transversely to its longitudinal direction. The slits 53a extend over the entire length of the insulation block 1 and the slits 53b extend over its entire width. Consequently, the connecting strips 5, 6 on which the edges of the sheets 11 of the secondary sealing barrier are welded are here produced discontinuously.

Moreover, as shown in the figure 25 , the metal sheets 11 of the secondary sealing barrier comprise two series of folds 12a, 12b, 12c, 12d. Each of the series has folds which are perpendicular to the folds of the other series. In addition, each series comprises one of the orthogonal folds 12a, 12b, housed in the interstices 10 formed between the insulation blocks 1, and a plurality of additional folds 12c, 12d which are parallel to said fold 12a, 12b. Additional folds 12c, 12d are identical with the folds 12 a and 12 b and form reliefs in the direction of the supporting wall 3. Additional folds are inserted into the slots 53a, 53b formed in the insulating block 1. Such a mode This embodiment makes it possible to further increase the flexibility of the secondary sealing barrier.

On the figure 27 , the folds 12 a , 12 b of the sheets 11 of the metal membrane of the secondary element are shown in dotted lines. Furthermore, the position of an insulation block 1 of the secondary thermal insulation barrier 10 is shown, by transparency. The position of an insulation block 13 of the primary thermal insulation barrier hooked onto the insulation blocks 1 of the secondary thermal insulation barrier 10 is also shown. In this embodiment, the primary sealing barrier has more than sheets 11 than insulation blocks 1. The primary sealing barrier here comprises twice as many sheets 11 as insulation blocks 11. The sheets 11 therefore have a length substantially equal to that of the insulation blocks 1 and a width which is substantially equal to half that of the insulation blocks. Thus, part of the sheets 11 is overlapped welded on four adjacent insulation blocks 1. The other part of the sheets 11 is overlapped welded on only two adjacent insulation blocks 1. In order to ensure the fixing of the sheets on the insulation blocks 1, these have three connecting strips 5a, 5b, 6. The connecting strip 5a is oriented transversely to the insulation block 1. The connecting strips 5a , 5b are arranged in the longitudinal direction of the insulation block 1.

The sheets 11 welded with overlap on four adjacent insulation blocks 1 each comprise two orthogonal folds 12 a , 12 b inserted in the interstices 10 formed between the insulation blocks 1. The sheets 11 welded with overlap on two insulation blocks 1 adjacent each have only a single ply 12b inserted between the two adjacent insulation blocks 1 between which it extends.

At the center of the crossings between the connecting strip 6 and the connecting strips 5a, 5b, the insulation blocks 1 comprise a stud 18 projecting towards the inside of the tank and making it possible to hang the insulation blocks 13 from the primary thermal insulation barrier.

The embodiment illustrated in figure 28 is substantially similar to that of the figure 27 . However, in this embodiment, the sheets 11 are identical and each have two orthogonal folds 12a, 12b. Consequently, the insulation blocks 1 comprise a median 53rd slot extending in their longitudinal direction. The middle 53rd slots accommodate the pleats 12a extending into the longitudinal direction of the sheets 11 welded to overlap on two adjacent insulation blocks 1.

Still other variations of corrugated sheets and other combinations can be designed by making modifications of various characteristics including corrugation spacing, number of corrugations per sheet, length of discontinuous corrugations (number of steps), the shape of the intersections between the corrugations, i.e. intersecting or non-secant intersection, the orientation of continuous corrugations, i.e. longitudinal or transverse orientation, and the orientation of the sheets themselves, i.e. horizontal orientation or vertical orientation (90 ° rotation), and combinations of such modifications.

The tanks described above can be used in different types of installations such as land installations or in a floating structure such as an LNG vessel or the like.

With reference to the figure 13 , 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 ship. The wall of the vessel 71 comprises a primary watertight barrier intended to be in contact with the LNG contained in the vessel, a secondary watertight barrier arranged between the primary watertight barrier and the double hull of the vessel, and two thermally insulating barriers arranged respectively between the vessel. primary watertight barrier and the secondary watertight barrier, and between the secondary watertight barrier and the double shell 72.

In a manner known per se, loading / unloading pipes arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a maritime or port terminal for transferring a cargo of LNG from or to the tank 71.

The figure 13 shows an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and an onshore installation 77. The loading and unloading station 75 is a fixed off-shore installation 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 pipes 73. The movable arm 74 can be swiveled and adapts to all sizes of LNG carriers. A connecting pipe (not shown) extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore installation 77. The latter comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75. The underwater pipe 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the shore installation 77 over a great distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a great distance from the coast during loading and unloading operations.

To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps fitted to the shore installation 77 and / or pumps fitted to the loading and unloading station 75 are used.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it comprises all the technical equivalents of the means described as well as their combinations if these come within the scope of the invention.

The use of the verb “comprise”, “understand” or “include” and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim. The use of the indefinite article "a" or "a" for an element or a stage does not exclude, unless otherwise stated, the presence of a plurality of such elements or stages.

In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims (27)

1. A fluidtight and thermally insulated tank built into a structure that includes a load-bearing wall, said tank having a tank wall attached to said load-bearing wall (3), the tank wall comprising:

   - a thermal insulation barrier held on the load-bearing wall (3) and made up of right-angled parallelepiped insulating blocks (1), juxtaposed in parallel rows separated from one another by gaps (10),

   - a fluidtight barrier carried by the thermal insulation barrier, said fluidtight barrier comprising a metal membrane formed of metal sheets (11) welded together sealingly,

   - each insulating block of the thermal insulation barrier carrying, on the face of same opposite the load-bearing wall (3), at least two substantially orthogonal metal connecting strips (5, 6), arranged parallel to the sides of the insulating block, the sheets (11) of the metal membrane carried by said insulating block being welded to said strips, said connecting strips being rigidly connected to the insulating block bearing same,
   the tank being characterized in that each sheet of a plurality of sheets (11) of the metal membrane has at least two orthogonal folds (12a, 12b) parallel to the sides of the thermal insulating blocks (1), said folds being inserted in the gaps (10) formed between the insulating blocks.
2. The tank as claimed in claim 1, characterized in that the tank wall has a primary element and a secondary element arranged between the load-bearing wall and the primary element, both the primary element and the secondary element including a thermal insulation barrier made up of right-angle parallelepiped insulating blocks (1, 13), juxtaposed in parallel rows and both the primary and secondary elements including a fluidtight barrier arranged on the thermal insulation barrier, the thermal insulation barrier of the secondary element being rigidly connected to the load-bearing wall (3), the thermal insulation barrier of the primary element being rigidly connected using attachment means (8, 18) connected to the thermal insulation barrier of the secondary element.
3. The tank as claimed in claim 2, characterized in that the fluidtight barrier of the secondary element is formed by the metal membrane comprising a plurality of sheets (11) each having at least two orthogonal folds (12a, 12b) parallel to the sides of the thermal insulating blocks (1), inserted in the gaps (10) formed between the insulating blocks of the secondary element.
4. The tank as claimed in claim 3, characterized in that the sheets (11) of the metal membrane of the secondary element are made of an alloy of iron with nickel or manganese, having a coefficient of expansion not exceeding 7×10^-6 K^-1.
5. The tank as claimed in any one of claims 2 to 4, characterized in that the fluidtight barrier of the primary element is formed of metal sheets (15) welded together sealingly, with folds (16a, 16b) oriented towards the inside of the tank.
6. The tank as claimed in one of claims 2 to 5, characterized in that an insulating block (1, 13) of the thermal insulation barrier has a base plate (2a, 13a) on which is arranged a foam layer, the base plate overhanging the foam.
7. The tank as claimed in claim 6, characterized in that an insulating block (1) of the thermal insulation barrier of the secondary element is pressed against the load-bearing wall (3) using fixtures (9) welded to the load-bearing wall and cooperating with the overhanging zones of the base plates (2a) of the insulating block.
8. The tank as claimed in one of claims 2 to 7, characterized in that an insulating block (1) of the thermal insulation barrier of the secondary element is held on the load-bearing wall by bonding.
9. The tank as claimed in one of claims 2 to 8, characterized in that each insulating block (1) of the thermal insulation barrier of the secondary element carries said two connecting strips (5, 6) that are arranged along the two axes of symmetry of the rectangle defined by a large face of said insulating block (1).
10. The tank as claimed in claim 9, characterized in that the attachment means of the thermal insulation barrier of the primary element include a continuous metal plate arranged at the crossing of the two connecting strips (5, 6) at the center of the rectangle of each insulating block (1) of the secondary element such as to form a fluidtight zone (39) to which the corners of the four sheets (11) can be welded about said attachment means, and a projecting member (8, 18) crossing the fluidtight barrier of the secondary element without reaching the fluidtight barrier of the primary element.
11. The tank as claimed in claim 10 combined with claim 6, characterized in that the projecting members are studs (8, 18), the bases of which are attached to the continuous metal plate placed at the crossing of two connecting strips of the insulating block of the secondary element, an intermediate part being interposed between firstly a nut (19, 22) cooperating with the thread provided at the free extremity of the stud and secondly the overhanging parts of the plates of the insulating blocks of the thermal insulation barrier of the primary element.
12. The tank as claimed in one of claims 2 to 11, characterized in that each insulating block (13) of the thermal insulation barrier of the primary element has two connecting strips (14a, 14b) that are arranged in the vicinity of the edges of a large face of said insulating block.
13. The tank as claimed in one of claims 1 to 12, characterized in that the connecting strips (5, 6, 14a, 14b) of an insulating block (1, 13) are seated in recesses formed in the insulating block bearing same so as not to increase the thickness on the corresponding face of the insulating block.
14. The tank as claimed in claim 13, characterized in that a connecting strip (5, 6, 14a, 14b) of an insulating block is attached to the recess of same by screwing, riveting, stapling or bonding.
15. The tank as claimed in one of claims 1 to 14, characterized in that the adjacent metal sheets (11, 15) of the fluidtight barrier are lap-welded level with the connecting strips (5, 6, 14a, 14b) carried respectively by the thermal insulation barrier.
16. The tank as claimed in one of claims 1 to 15, characterized in that the metal sheets (11), which form the fluidtight barrier, are rectangular and each have two folds formed along the axes of symmetry of the rectangle formed by the edges of the rectangular sheet.
17. The tank as claimed in claim 16, characterized in that the two folds of a sheet (11) of the fluidtight barrier are secant at the center of the rectangular sheet.
18. The tank as claimed in claim 16, characterized in that one of the folds of a sheet (11) of the fluidtight barrier is continuous and the other is interrupted in the central portion of same.
19. The tank as claimed in claim 18, characterized in that the fluidtight barrier includes sheets (31) of a first type that have a continuous fold along the major axis of same and sheets (32) of a second type have a continuous fold along the minor axis of same, the first and second types of sheet (31, 32) alternating regularly on a tank wall so that one sheet of one of the types is always surrounded by four sheets of the other type arranged along the four sides of same.
20. The tank as claimed in one of claims 1 to 19, characterized in that each insulating block (1) of the thermal insulation barrier has two series of orthogonal slots (53a, 53b), each of said series having slots (53a, 53b) arranged parallel to two opposing sides of the insulating block (1), and in that the sheets (11) of the metal membrane each have two series of supplementary folds (12c, 12d), each of said series of supplementary folds having folds (12c, 12d) orthogonal to the folds (12d, 12c) in the other series, parallel to one of the two folds (12a, 12b) inserted in the gaps (10), and inserted into the slots (53a, 53b) of one of the series of slots (53a, 53b) formed in the insulating block (1).
21. The tank as claimed in one of claims 1 to 19, characterized in that the metal membrane has a second plurality of sheets (11), each of the sheets in the second plurality having a single fold (12a) parallel to two opposing sides of the insulating blocks (1), said fold being inserted into a gap (10) formed between two insulating blocks.
22. The tank as claimed in one of claims 1 to 19, characterized in that each insulating block (1) of the thermal insulation barrier has a slot parallel to two opposing sides of the insulating blocks and in which the metal membrane has a second plurality of sheets, each of the sheets in the second plurality having a fold (12a) inserted in a slot (53e) formed in an insulating block (1) and a fold (12b) inserted in a gap (10) formed between two insulating blocks.
23. The tank as claimed in one of claims 1 to 22, wherein each of the two connecting strips (5, 6) is discontinuous,
24. The tank as claimed in one of claims 1 to 22, wherein each of the two connecting strips (5, 6) is continuous at the intersection with the other connecting strip (5, 6) and is formed of discontinuous juxtaposed segments apart from the intersection.
25. A ship (70) used to transport a cold liquid product, the ship having a double hull (72) and a tank (71) as claimed in one of claims 1 to 22 placed inside the double hull.
26. Use of a ship (70) as claimed in claim 23 for loading or offloading a cold liquid product, in which a cold liquid product is channeled through insulated pipes (73, 79, 76, 81) to or from a onshore or floating storage facility (77) to or from the tank on the ship (71).
27. A transfer system for a cold liquid product, the system including a ship (70) as claimed in claim 23, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) installed in the hull of the ship to an onshore or floating storage facility (77) and a pump for driving a flow of cold liquid product through the insulated pipes to or from the onshore or floating storage facility to or from the tank on the ship.

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