EP3803187B1 - Thermally-insulating sealed tank - Google Patents

Description

Technical area

The invention relates to the field of waterproof and thermally insulating membrane tanks for the storage and/or transport of fluid, such as a liquefied gas.

Tight and thermally insulating membrane tanks are used in particular for the storage of liquefied natural gas (LNG), which is stored at atmospheric pressure at approximately -163°C. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank may be intended for the transport of liquefied natural gas or to receive liquefied natural gas serving as fuel for the propulsion of the floating structure.

Technology background

The document WO-A-89/09909 discloses a sealed and thermally insulating tank for storing liquefied natural gas arranged in a supporting structure and whose walls have a multi-layer structure, namely from the outside towards the inside of the tank, a secondary thermally insulating barrier anchored against the structure carrier, a secondary waterproof membrane which is supported by the secondary thermally insulating barrier, a primary thermally insulating barrier which is supported by the secondary waterproof membrane and a primary waterproof membrane which is supported by the primary thermally insulating barrier and which is intended to be in contact with liquefied natural gas stored in the tank. The primary insulating barrier comprises a set of rigid plates which are held by means of the weld supports of the secondary waterproof membrane.

In one embodiment, the primary waterproof membrane is formed by an assembly of rectangular sheets having undulations in two perpendicular directions, said sheets being welded together overlapping and being welded by their edges on metal strips fixed in rebates along of the edges of the plates of the primary insulating barrier.

EP0064886A1 describes a watertight and insulating tank, integrated into the supporting structure of a ship, comprising two successive alternating sealing barriers with two thermally insulating barriers. The secondary sealing barrier is made up of an assembly of welded invar strakes with raised edges. The primary sealing barrier is made up of an assembly of sheets, the edges of which are overlap welded and attached to the primary insulating barrier by welding onto metal inserts of the primary insulating barrier. In one embodiment, the sheets are embossed and have corrugations in two perpendicular directions.

WO2008007837A1 describes an LNG tank whose wall includes a secondary membrane formed of invar strakes welded to tongues carried by secondary insulation panels. A primary insulation panel is located on each invar strake placed between the tongues and a connection unit connects the edge of the primary insulation panel to each adjacent tongue.

Summary

An idea underlying the invention consists of providing a tank wall combining the advantages of a secondary membrane formed of parallel strakes, the robustness of which has been proven by experience, and of a corrugated primary membrane, which can present very good resistance to accidental indentations and other stresses, resulting for example from thermal contraction, cargo movements and/or deformation of the ship's beam at sea.

Another idea underlying the invention consists of providing a tank wall which is relatively easy to manufacture and which allows different types of corrugated waterproof membranes to be used as a primary membrane.

The invention proposes a waterproof and thermally insulating tank according to claim 1.

According to one embodiment, the primary rows are offset in the second direction by a fraction, for example half, of the dimension of the repeated pattern of the secondary rows relative to the secondary rows. Thanks to such an offset, it is possible to limit or eliminate the vertical alignments between primary retaining members and secondary retaining members, which limits the occurrence of thermal bridges caused by these alignments.

Another advantage of shifting the primary rows in the first and/or second direction is to obtain a more uniform distribution of the forces passing through the membranes and the primary insulation and being reflected on the secondary insulating panels and the supporting wall. Indeed, in this case, a pressure force exerted on a primary insulating panel is distributed over several, for example two or four, underlying secondary insulating panels.

According to one embodiment, the interfaces between the primary insulating panels within a primary row are offset in the first direction relative to the interfaces between the secondary insulating panels within the two secondary rows on which the primary row is superimposed.

Preferably in this case, the primary retaining members are carried by the secondary insulating panels at a distance from the edges of the secondary insulating panels, for example at the centers of the secondary insulating panels.

Such primary retaining members can be provided on all the secondary insulating panels, for example if the primary insulating panel has the same dimensions as the secondary insulating panel, or on some of the secondary insulating panels, for example if the primary insulating panel is more long as the secondary insulating panel or if the primary insulating panel is offset only in the first direction.

According to the invention, a primary retaining member comprises a plate fixed to a cover plate of the secondary insulating panel under the secondary waterproof membrane and a rod attached to said plate, fixedly or with a horizontal clearance, and passing through the membrane in a sealed manner secondary waterproofing towards the primary insulating barrier.

According to the invention, the primary waterproof membrane has first undulations parallel to the first direction and arranged in a repeated pattern in the second direction and flat portions located between the first undulations and resting on an upper surface of the primary insulating panels, and the dimension of the repeated pattern of the primary rows is an integer multiple of the dimension of the repeated pattern of the first undulations,
the primary waterproof membrane comprising a plurality of rows of sheets parallel to the first direction, a row of sheets comprising a plurality of rectangular sheets welded together in a sealed manner by edge zones, without or with mutual overlap, the rows of sheets being juxtaposed in the second direction and welded together in a sealed manner, the dimension of a row of sheets in the second direction being equal to an integer multiple of the dimension of the repeated pattern of the primary rows.

The repeated pattern of the first ripples may be a repeated pattern comprising one ripple or several ripples. A repeating pattern having a single undulation means that the first undulations are spaced a first regular spacing in the second direction and that the dimension of the repeating pattern is equal to this first even spacing. In this case, the dimension of the repeated pattern of the primary rows is an integer multiple of said first regular spacing. A repeating pattern with multiple ripples means that the spacing of the ripples is not necessarily regular, but all spacings repeat at a regular interval, called the dimension of the ripple repeat pattern.

According to the invention, the rows of sheets are offset in the second direction relative to the primary rows so that the welded junctions between the rows of sheets are located at a distance from the interfaces between the primary rows, that is to say in particular at a distance retaining devices.

Thanks to these characteristics, the welded junctions between the rows of sheets of the primary waterproof membrane can essentially be made at a distance from the edges of the primary insulating panels parallel to the first direction, therefore on a surface having a high level of flatness. This results in a lower risk of local variation of the welds and a higher level of quality of the membrane obtained.

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

According to one embodiment, a primary row comprises a plurality of parallelepiped primary insulating panels juxtaposed in a repeated pattern and a row of sheets of the primary waterproof membrane comprises a plurality of rectangular sheets juxtaposed in a repeated pattern, the dimension of the repeated pattern rectangular sheets being equal to an integer multiple of the dimension of the repeated pattern of the primary insulating panels in the first direction.

According to one embodiment, the edges of the rectangular sheets are offset in the first direction relative to the edges of the primary insulating panels parallel to the second direction, so that the welded junctions between the rectangular sheets are located at a distance from the edges of the insulating panels primaries parallel to the second direction.

According to one embodiment, the primary insulating panels and/or the secondary insulating panels have a square shape.

The primary row repeat pattern and/or the secondary row repeat pattern may or may not have a gap in the second direction. If there is a gap between two rows, the dimension of the repeated pattern is equal to the sum of the dimension of the primary or secondary insulating board and the dimension of the gap.

Likewise, the repeated pattern of primary or secondary insulating panels within a primary or secondary row may or may not have a gap in the first direction. If there is a gap between two primary or secondary insulating panels, the dimension of the repeating pattern is equal to the sum of the dimension of the primary or secondary insulating panel and the dimension of the gap.

According to one embodiment, the dimension of a strake in the second direction is an integer multiple of said first regular spacing. These characteristics facilitate the possibility of choosing the orientation of the strakes according to the local requirements of the intended application.

According to one embodiment, the primary waterproof membrane also has second undulations parallel to the second direction and arranged in a repeated pattern in the first direction, the flat portions being located between the first undulations and between the second undulations.

The repeating pattern of the second ripples may be a repeating pattern comprising one ripple or multiple ripples. A repeating pattern with a single ripple means that the second ripples are spaced one second regular spacing in the first direction. In this case, the second regular spacing may be equal to or different from the first regular spacing. A repeating pattern with multiple ripples means that the spacing of the ripples is not necessarily regular, but all spacings repeat at a regular interval, called the dimension of the ripple repeat pattern.

According to embodiments, the first and second undulations can be continuous or discontinuous at the intersections between first and second undulations. Thanks to continuous undulations, it is possible to produce continuous channels, for example for the circulation of a neutral gas, between the primary waterproof membrane and the primary insulating barrier. Thanks to discontinuous corrugations, it is easier to form the sheet by stamping.

According to one embodiment, the dimension of the repeated pattern of the primary insulating panels is an integer multiple of the dimension of the repeated pattern of the second corrugations, for example an integer multiple of said second regular spacing.

According to one embodiment, a rectangular sheet of the primary waterproof membrane has a dimension in the first direction substantially equal to an integer multiple of the dimension of the repeated pattern of the second undulations or an integer multiple of the second regular spacing. A slight difference may exist between these two quantities, less than the dimension of the overlap between two adjacent sheets.

The primary waterproof membrane is retained on the primary insulating barrier by anchoring means which can be produced in different ways.

According to one embodiment, the anchoring means comprise metal anchoring strips fixed on the primary insulating panels at locations corresponding to the contours of the rectangular sheets and on which edge zones of the rectangular sheets can be welded. A primary insulating panel may in particular comprise an anchoring strip for fixing a rectilinear edge of one or more rectangular sheets or two intersecting anchoring strips for fixing a corner zone of one or more rectangular sheets.

According to one embodiment, the anchoring means comprise metal inserts, for example in the form of discs, fixed on the primary insulating panels at locations corresponding to edge zones of the primary insulating panels distant from the contours of the rectangular sheets and on which central areas of rectangular sheets can be welded.

According to one embodiment, a primary insulating panel comprises relaxation slots cut in a direction of thickness of the primary insulating panel and opening onto a cover plate of the primary insulating panel. According to embodiments, one or each metal anchor strip may comprise several aligned segments, fixed on the cover plate and separated by the relaxation slots and/or the metal inserts can be fixed on the cover plate between the slots relaxation.

According to one embodiment, at least one of the insulating panels comprises a bottom plate resting against the supporting structure or the secondary waterproof membrane, an intermediate plate placed between the bottom plate and the cover plate, a first layer of insulating polymer foam sandwiched between the bottom plate and the intermediate plate and a second layer of insulating polymer foam sandwiched between the intermediate plate and the cover plate. Such a structure is advantageous in that it makes it possible to limit the bending forces generated by the differential contraction of the materials of the insulating panel.

According to one embodiment, recesses are provided in the second layer of insulating polymer foam so that the intermediate plate projects beyond the second layer of insulating polymer foam and thus provides one of the support zones for the secondary restraints.

According to one embodiment, the first layer of insulating polymer foam has, in each of the corner zones of the insulating panel, a cutout housing a pillar which extends between the bottom plate and the intermediate plate. This helps limit crushing and creep of the foam.

According to another embodiment, at least one of the insulating panels comprises a bottom plate, a cover plate and supporting sails extending, in the thickness direction of the tank wall, between the bottom plate and the cover plate and delimiting a plurality of compartments filled with an insulating lining, such as perlite.

According to one embodiment, a bridging element can be attached to the upper surfaces of several adjacent primary insulating panels, for example two or four adjacent primary insulating panels, for example to the cover plates of the adjacent primary insulating panels, to avoid spacing adjacent primary insulating panels, in other words to avoid the creation of a gap between the adjacent primary insulating panels or at least the widening thereof. According to one embodiment, the primary insulating panels have countersinks on the edges of the upper surface to receive the bridging element(s), for example plywood bridging plates.

According to one embodiment, the fluid is a liquefied gas, such as liquefied natural gas.

Such a tank can be part of a land storage installation, for example to store LNG or be installed in a floating, coastal or deep water structure, in particular an LNG ship, 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 cryogenic fluid comprises a double hull and a aforementioned tank placed in the double hull.

According to one embodiment, the double shell comprises an internal shell forming the supporting structure of the tank.

According to one embodiment, the invention also provides a method of loading or unloading such a vessel, in which a fluid is conveyed through insulated pipes from or to a floating or terrestrial storage installation to or from the tank of the ship.

According to one embodiment, the invention also provides a transfer system for a fluid, 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 or land storage installation and a pump for driving fluid through the insulated pipelines to or from the floating or land-based storage facility to or from the vessel tank.

Brief description of the figures

• La figure 1 est une vue en perspective écorchée d'une paroi de cuve utile à la compréhension de l'invention, mais qui ne fait pas partie de l'invention.
• La figure 2 est une vue en perspective d'un panneau isolant secondaire pouvant être utilisé dans la paroi de cuve.
• La figure 3 est une vue en perspective d'un panneau isolant primaire pouvant être utilisé dans la paroi de cuve.
• La figure 4 est une vue en perspective d'un dispositif de retenue pouvant coopérer avec des panneaux isolants primaires et des panneaux isolants secondaires afin de les retenir contre la structure porteuse.
• La figure 5 est une vue éclatée du dispositif de retenue de la figure 4.
• La figure 6 est une vue agrandie de la zone VI de la figure 1, montrant en outre des moyens d'ancrage de la membrane primaire selon un premier mode de réalisation.
• La figure 7 est une vue en coupe agrandie selon la ligne VII-VII de la figure 6.
• La figure 8 est une vue analogue à la figure 6, montrant en outre des éléments de pontage de la barrière isolante primaire.
• La figure 9 est une vue en coupe agrandie selon la ligne IX- IX de la figure 8.
• La figure 10 est une vue analogue à la figure 6, montrant des moyens d'ancrage de la membrane primaire selon un deuxième mode de réalisation.
• La figure 11 est une représentation schématique écorchée d'une cuve de navire méthanier et d'un terminal de chargement/déchargement de cette cuve.
• La figure 12 est une vue en perspective écorchée d'une paroi de cuve selon un mode de réalisation de l'invention.
• La figure 13 est une vue agrandie de la zone XIII de la figure 12, montrant en outre un organe d'ancrage primaire selon un mode de réalisation.
• La figure 14 est une vue en perspective écorchée d'une paroi de cuve selon un autre mode de réalisation.

The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation. , with reference to the attached drawings.

• There figure 1 is a cutaway perspective view of a tank wall useful for understanding the invention, but which is not part of the invention.
• There figure 2 is a perspective view of a secondary insulating panel that can be used in the tank wall.
• There Figure 3 is a perspective view of a primary insulating panel suitable for use in the tank wall.
• There Figure 4 is a perspective view of a retaining device capable of cooperating with primary insulating panels and secondary insulating panels in order to retain them against the supporting structure.
• There Figure 5 is an exploded view of the retainer of the Figure 4 .
• There Figure 6 is an enlarged view of zone VI of the figure 1 , further showing means for anchoring the primary membrane according to a first embodiment.
• There Figure 7 is an enlarged sectional view along line VII-VII of the Figure 6 .
• There figure 8 is a view analogous to the Figure 6 , further showing bridging elements of the primary insulating barrier.
• There Figure 9 is an enlarged sectional view along line IX-IX of the figure 8 .
• There Figure 10 is a view analogous to the Figure 6 , showing means for anchoring the primary membrane according to a second embodiment.
• There Figure 11 is a cut-away schematic representation of an LNG ship tank and a loading/unloading terminal for this tank.
• There Figure 12 is a cutaway perspective view of a tank wall according to one embodiment of the invention.
• There Figure 13 is an enlarged view of zone XIII of the Figure 12 , further showing a primary anchoring member according to one embodiment.
• There Figure 14 is a cutaway perspective view of a tank wall according to another embodiment.

Detailed description of embodiments

On the figure 1 , we have shown the multilayer structure of a wall 1 of a sealed and thermally insulating tank for the storage of a liquefied fluid, such as liquefied natural gas (LNG). Each wall 1 of the tank successively comprises, in the direction of thickness, from the outside towards the inside of the tank, a secondary thermally insulating barrier 2 retained on a supporting wall 3, a secondary waterproof membrane 4 resting against the secondary thermally insulating barrier 2, a primary thermally insulating barrier 5 resting against the secondary waterproof membrane 4 and a primary waterproof membrane 6 intended to be in contact with the liquefied natural gas contained in the tank.

The supporting structure can in particular be formed by the hull or double hull of a ship. The supporting structure comprises a plurality of supporting walls 3 defining the general shape of the tank, usually a polyhedral shape.

The secondary thermally insulating barrier 2 comprises a plurality of secondary insulating panels 7 which are anchored on the supporting wall 3 by means of retaining devices 98 which will be described in detail subsequently. The secondary insulating panels 7 have a general parallelepiped shape and are arranged in parallel rows. Three rows are indicated by the letters A, B and C. Rolls of putty 99 are interposed between the secondary insulating panels 7 and the supporting wall 3 to compensate for the deviations of the supporting wall 3 in relation to a flat reference surface. A kraft paper is inserted between rolls of putty 99 and the supporting wall 3 to prevent adhesion of the rolls of putty 99 to the supporting wall 3.

There figure 2 represents the structure of a secondary insulating panel 7 according to one embodiment. The secondary insulating panel 7 here comprises three plates, namely a bottom plate 8, an intermediate plate 9 and a cover plate 10. The bottom 8, intermediate 9 and cover 10 plates are for example made of plywood. The secondary insulating panel 7 also comprises a first layer of insulating polymer foam 11 sandwiched between the bottom plate 8 and the intermediate plate 9 and a second layer of insulating polymer foam 12 sandwiched between the intermediate plate 9 and the base plate. cover 10. The first and second layers of insulating polymer foam 11, 12 are respectively glued to the bottom plate 8 and the intermediate plate 9 and to the intermediate plate 9 and the cover plate 10. The insulating polymer foam can in particular be a polyurethane-based foam, optionally reinforced with fibers.

The first layer of insulating polymer foam 11 has, in the corner zones, cutouts to allow corner pillars 13 to pass through. The corner pillars 13 extend, at the level of the four corner zones of the secondary insulating panel 7, between the bottom plate 8 and the intermediate plate 9. The corner pillars 13 are fixed, for example by means of staples or screws or glue, on the bottom plate 8 and the intermediate plate 9. The corner pillars 13 are, for example, made of plywood or plastic. The corner pillars 13 make it possible to take up part of the compressive load in service and to limit the crushing and creep of the foam. Such corner pillars 13 have a coefficient of thermal contraction different from that of the first layer of insulating polymer foam 11. Also, when the tank is cooled, the deflection of the secondary insulating panel 7 can be lower at level of the corner pillars 13 than in the other areas.

Furthermore, the secondary insulating panel 7 has recesses 14, 54 at its corner areas to receive retaining devices 98 which will be detailed later. The secondary insulating panel 7 comprises, from the bottom plate 8 to the intermediate plate 9, a first recess 14 intended to allow the passage of a rod 15 of the retaining device 98. Above the intermediate plate 9, the panel secondary insulator 7 comprises a second recess 54. The second recess 54 has dimensions greater than those of the first recess 14 so that the intermediate plate 9 projects beyond the second layer of insulating polymer foam 12 and the cover plate 10. Thus, the intermediate plate 9 forms at the corner zones of the secondary insulating panel 7 a support zone 16 intended to cooperate with a secondary support plate 17 of the retaining device 98.

Furthermore, the cover plate 10 has a countersink 18 at these four corner zones. Each countersink 18 is intended to receive a force distribution plate 19 of the retaining device 98. The countersinks 18 have a thickness substantially similar to that of the force distribution plate 19 so that the force distribution plate 19 is flush with the upper surface of the cover plate 10. The cover plate 10 also has grooves 20 for receiving solder supports.

The structure of the secondary insulating panel 7 is described above by way of example. Also, in another embodiment, the secondary insulating panels 7 are likely to have another general structure, for example that described in the document WO2012/127141 . The secondary insulating panels 7 are then produced in the form of a box comprising a bottom plate, a cover plate and supporting sails extending, in the direction of thickness of the tank wall 1, between the bottom plate and the cover plate and delimiting a plurality of compartments filled with an insulating filling, such as perlite, glass wool or rock wool.

Returning to the figure 1 , we observe that the secondary waterproof membrane 4 comprises a continuous layer of metal strakes 21, with raised edges. The strakes 21 are welded by their raised edges 32 on parallel welding supports which are fixed in the grooves 20 made on the cover plates 10 of the secondary insulating panels 7. The strakes 21 are, for example, made of Invar ^® : c that is to say an alloy of iron and nickel whose coefficient of expansion is typically between 1.2.10 ^-6 and 2.10 ^-6 K ^-1 . It is also possible to use iron and manganese alloys whose expansion coefficient is typically of the order of 7.10 ^-6 K ^-1 .

The primary thermally insulating barrier 5 comprises a plurality of primary insulating panels 22 which are anchored on the supporting wall 3 by means of the aforementioned retaining devices 98. The primary insulating panels 22 have a general parallelepiped shape. In addition, they have dimensions identical to those of the primary insulating panels 22 with the exception of their thickness in the direction of thickness of the tank wall 1 which is likely to be different, and in particular weaker. Each of the primary insulating panels 22 is positioned to the right of one of the secondary insulating panels 7, in alignment with the latter in the direction of thickness of the tank wall 1.

There Figure 3 represents the structure of a primary insulating panel 22 according to one embodiment. The primary insulating panel 22 has a multilayer structure similar to that of the secondary insulating panel 7 of the figure 2 . Also, the primary insulating panel 22 successively comprises a bottom plate 23, a first layer of insulating polymer foam 24, an intermediate plate 25, a second layer of insulating polymer foam 26 and a cover plate 27. The insulating polymer foam can in particular be a polyurethane-based foam, optionally reinforced with fibers.

The primary insulating panel 22 has recesses 28 at its corner zones so that the bottom plate 23 projects beyond the first layer of insulating polymer foam 24, to the intermediate plate 25, to the second layer of insulating polymer foam 26 and the cover plate 27. Thus, the bottom plate 23 forms at the corner zones of the primary insulating panel 22 a support zone 29 intended to cooperate with a primary support plate 30 of the device retainer 98. Not shown, a shim can be added to the bottom plate 23, said shim having a shape similar to that of the support zone 29 and being intended to cooperate with the primary support plate 30 of the retaining device 98.

The bottom plate 23 has grooves 31 intended to receive the raised edges 32 of the strakes 21 of the secondary waterproof membrane 4. The bottom plate cover 27 may also include anchoring means, not shown on the figures 1 And 3 , to anchor the primary waterproof membrane 6.

The structure of the primary insulating panel 22 is described above by way of example. Also, in another embodiment, the primary insulating panels 22 are likely to have another general structure, for example that described in the document WO2012/127141 .

In another embodiment, the primary thermally insulating barrier 5 comprises primary insulating panels 22 having at least two different types of structure, for example the two aforementioned structures, depending on their installation area in the tank.

There figure 1 also shows that the primary waterproof membrane 6 comprises a continuous layer of rectangular sheets 33 which have two series of mutually perpendicular undulations. The first series of corrugations 55 extends perpendicular to the rows of insulating panels A, B, C and therefore perpendicular to the raised edges 32 of the strakes 21 and has a regular spacing 57. The second series of corrugations 56 extends parallel to the rows of insulating panels A, B, C and therefore parallel to the raised edges 32 of the strakes 21 and has a regular spacing 58. Preferably, the first series of corrugations 55 is higher than the second series of corrugations 56.

The rectangular sheets 33 are welded together by forming small overlapping zones 59 along their edges, according to the known technique.

A rectangular sheet 33 preferably has width and length dimensions which are equivalent to integer multiples of the spacing of the corresponding corrugations and also integer multiples of the dimensions of the primary insulating panels 22. figure 1 shows a rectangular sheet 33 which measures 4 times the spacing 57 by 12 times the spacing 58. Preferably the spacings 57 and 58 are equal. Thus, the orientation of the corrugations 55 and 56 in the tank can be easily adapted to the requirements of the application without causing significant modifications to the construction of the insulation barriers.

For example, in a variant embodiment, the primary waterproof membrane 6 is rotated by 90° so that the first series of undulations 55 extends parallel to the rows of insulating panels A, B, C and therefore parallel to the raised edges 32 of the strakes 21.

The primary insulating panels 22 and the secondary insulating panels 7 have the same dimension in the width direction of the rows A, B, C. This dimension will be called the length of the insulating panels by convention. This row width is an integer multiple of the spacing of the undulations in the same direction, here the spacing 58, and an integer multiple of the width of the strakes 21, to facilitate the manufacture of the tank wall in a modular manner by forming patterns repeated a large number of times over substantially the entire supporting wall 3.

Preferably, the width of a strake 21 is an integer multiple of the spacing of the undulations in the same direction, for example double.

In the length direction of rows A, B, C, a primary insulating panel 22 may have the same dimension as a secondary insulating panel 7 or an integer multiple of this dimension. This dimension is an integer multiple of the spacing of the undulations in the same direction, here the spacing 57, to facilitate the manufacture of the tank wall in a modular manner by forming patterns repeated a large number of times over the entire supporting wall 3.

Preferably, the primary insulating panels 22 and the secondary insulating panels 7 are square in shape. This makes it easier to adapt the relative orientation of the strakes and corrugations in the tank without requiring significant modifications to the design of the insulating panels.

Preferred dimensional example

• Spacing of corrugations 57, 58: PO
• Width of primary insulating panel 22 and secondary insulating panel 7: 4PO
• Length of primary insulating panel 22 and secondary insulating panel 7: 4PO (square shape)
• Width of a strake 21: 2PO
• Length of a sheet 33: 12PO ( Fig. 1 ) or 8PO (not shown)
• Width of a sheet 33: 4IN
• PO = 300 mm.

With these dimensions, a good compromise is obtained between the ease of handling of the parts making up the tank wall and the number of parts that must be assembled. This arrangement also simplifies the connection of the corrugations between two walls of a tank.

Dimensional Example 2

• Corrugation spacing 58: PO
• Ripple spacing 57: GO
• Width of primary insulating panel 22 and secondary insulating panel 7: 3GO
• Length of primary insulating panel 22 and secondary insulating panel 7: 4PO (rectangular shape)
• Width of a strake 21: 2PO
• Length of a sheet 33: 12PO
• Width of a sheet 33: 3GB
• PO = 300 mm
• GB = 340 mm

Example 3

The undulations 55 are not equidistant, but arranged in a repeated pattern of four undulations 55, the successive spacings of which are:
340; 340; 340; 180mm

Preferably, the 180 mm interval is divided into two 90 mm portions located on two opposite edges of the rectangular sheet 33.

The dimension of the repeated pattern is therefore 1200mm. For the rest, the dimensions of the first example are preserved.

Example 4

The undulations 55 are not equidistant, but arranged in a repeated pattern of four undulations 55, the successive spacings of which are:
300; 400; 300; 200mm

Preferably, the 200 mm interval is divided into two 100 mm portions located on two opposite edges of the rectangular sheet 33.

The dimension of the repeated pattern is therefore 1200mm. For the rest, the dimensions of the first example are preserved.

As shown on the figure 1 , the retaining devices 98 are positioned at the four corners of the primary insulating panels 22 and secondary 7. Thus, each stack of a secondary insulating panel 7 and a primary insulating panel 22 is anchored to the supporting wall 3 by means of four retaining devices 98. Thus the retaining device 98 here comprises a primary retaining member superimposed on a secondary retaining member. In addition, each retaining device 98 cooperates with the corners of four adjacent secondary insulating panels 7 and with the corners of four adjacent primary insulating panels 22.

THE figures 3 And 4 illustrate more precisely the structure of a retaining device 98 according to one embodiment.

The retaining device 98 comprises a socket 34 whose base is welded to the supporting wall 3 in a position which corresponds to a clearance at the corner areas of four adjacent secondary insulating panels 7. The socket 34 houses a nut 35, shown on the Figure 4 , into which the lower end of a rod 15 is screwed. The rod 15 passes between the adjacent secondary insulating panels 7.

The rod 15 passes through a bore made in an insulating plug 36 intended to ensure continuity of the secondary thermal insulation at the level of the retaining device 98. The insulating plug 36 presents, in a plane orthogonal to the direction of thickness of the tank wall 1, a cross-shaped section which is defined by four branches. Each of the four branches is inserted in a gap provided between two of the four adjacent secondary insulating panels 7.

The retaining device 98 further comprises a secondary support plate 17 which bears in the direction of the supporting wall 3 against the support zone 16 formed in each of the four adjacent secondary insulating panels 7 in order to retain them against the supporting wall 3. In the embodiment shown, the secondary support plate 17 is housed in the second recess 54 formed in the second layer of insulating polymer foam 12 of each of the secondary insulating panels 7 and is supported against a zone of the intermediate plate 9 which forms the support zone 16.

A nut 37 cooperates with a thread provided at the upper end of the rod 15 so as to ensure retention of the secondary support plate 17 on the rod 15.

In the embodiment shown, the retaining device 98 further comprises one or more elastic washers 38, of the Belleville type. The elastic washers 38 are threaded onto the rod 15 between the nut 37 and the secondary support plate 17, which ensures elastic anchoring of the secondary insulating panels 7 on the supporting wall 3. In addition, advantageously , a locking member 39 is locally welded to the upper end of the rod 15, so as to fix the nut 37 in position on the rod 15.

The retaining device 98 further comprises a force distribution plate 19, an upper plate 40 and a spacer 41 which are fixed to the secondary support plate 17.

The force distribution plate 19 is housed in each of the countersinks 18 provided in the cover plates 10 of the four adjacent secondary insulating panels 7. The force distribution plate 19 is therefore positioned between the cover plates 10 of each of the four secondary insulating panels and the secondary waterproof membrane 4. The force distribution plate 19 aims to attenuate the phenomena of unevenness between the corners of the insulating panels secondary 7 adjacent. Also, the force distribution plate 19 makes it possible to distribute the stresses likely to be exerted on the secondary waterproof membrane 4 and the primary insulating panels 22 to the right of the corner zones of the secondary insulating panels 7. Therefore, the distribution plate forces 19 makes it possible to limit the phenomena of punching of the bottom plates 23 of the primary insulating panels 22 and of punching and settling of the layers of insulating polymer foam 24, 26 of the primary insulating panels 22 to the right of the corner zones of the secondary insulating panels 7.

The force distribution plate 19 is advantageously made of a metal chosen from stainless steel, iron and nickel alloys, such as invar, whose expansion coefficient is typically between 1.2.10 ^-6 and 2.10 ^-6 K ^-1 and iron and manganese alloys whose expansion coefficient is less than 2.10 ^-5 K ^-1 , typically of the order of 7.10 ^-6 K ^-1 . The force distribution plate 19 has a thickness of between 1 and 7 mm, preferably between 2 and 4 mm, for example of the order of 3 mm. The force distribution plate 19 advantageously has a square shape whose dimension on one side is between 100 and 250 mm, for example of the order of 150 mm.

The upper plate 40 is arranged below the force distribution plate 19 and has dimensions smaller than that of the force distribution plate 19 so that the force distribution plate 19 completely covers the upper plate 40. upper plate 40 is housed in the recesses 15 provided in the corner zones of the secondary insulating panels 7, to the right of the support zones 16, that is to say in the embodiment shown on the Figure 4 , in the recesses 54 made in the second layer of insulating polymer foam 12 of the secondary insulating panels 7.

The upper plate 40 has a threaded bore 42 in which is mounted a threaded base of a stud 43 intended for anchoring the primary insulating panels 22. In order to allow the fixing of the stud 43 to the upper plate 40, the distribution plate forces 19 also includes a bore, provided facing the threaded bore of the upper plate 40, and thus allowing the stud 43 to pass through the force distribution plate 19.

The upper plate 40 has a general shape of a rectangular parallelepiped comprising two large opposite faces which are parallel to the supporting wall 3 and four faces which connect the two large faces and extend parallel to the direction of thickness of the tank wall 1 . In the embodiment illustrated on the figures 3 to 4 , the four faces which extend parallel to the direction of thickness of the tank wall 1 are connected by fillets 44. This makes it possible to avoid the presence of sharp angles and contributes to further limiting the punching phenomena of the bottom plates 23 of the primary insulating panels 22 by limiting the stress concentrations.

In an embodiment not illustrated, the upper plate 40 and the force distribution plate 19 can be formed in a single single piece.

The spacer 41 is arranged between the secondary support plate 17 and the upper plate and thus serves to maintain a spacing between the secondary support plate 17 and the upper plate 40. In the embodiment illustrated on the figures 3 to 4 , the spacer 41 has chamfers 45 in order to fit into the overall dimensions, seen in the direction of thickness of the tank wall 1, of the upper plate 40. In other words, the upper plate 40 completely covers the spacer 41.

The spacer 41 is advantageously made of wood which makes it possible to limit the thermal bridge towards the supporting wall 3 at the level of the retaining device 98. The spacer 41 has an inverted U shape so as to define between the two branches of the U a central housing 46. The central housing 46 receives the upper end of the rod 15, the locking member 39, the nut 37 and the elastic washers 38. The spacer 41 is also housed in the recess 15 made, at the right of the support surface 16.

The locking member 39 has a square or rectangular shape whose diagonal has a dimension greater than the dimension of the central housing 46 between the two branches of the U, which makes it possible to lock the rod 15 in rotation relative to the spacer 39 and thus prevents the rod 15 from disengaging from the nut 35.

In order to fix the force distribution plate 19, the upper plate 40, the spacer 41 and the secondary support plate 17 to each other, the aforementioned elements are each provided with two bores through each of which a screw passes 47, 48. The bores formed in the secondary support plate 17 each have a thread cooperating with one of the screws 47, 48 so as to ensure the fixing of the aforementioned elements to each other.

Furthermore, the stud 43 passes through a hole made through a strake 21 of the secondary waterproof membrane 4. The stud 43 has a collar 49 which is welded to its periphery, around the hole, to ensure the tightness of the secondary waterproof membrane 4. The secondary waterproof membrane is therefore sandwiched between the flange 49 of the stud 43 and the force distribution plate 19.

The retaining device 98 also comprises a primary support plate 30 which is supported in the direction of the supporting wall 3 on a support zone 29 provided in each of the four adjacent primary insulating panels 22 so as to retain them against the wall carrier 3. In the embodiment shown, each support zone 29 is formed by an overhanging part of the bottom plate 23 of one of the primary insulating panels 22. The primary support plate 30 is housed in the recesses 28 provided in the corner zones of the primary insulating panels 22, to the right of the support zones 29.

A nut 50 cooperates with a thread provided at the upper end of the stud 43 so as to ensure the fixing of the primary support plate 30 on the stud 43. In the embodiment shown, the retaining device 98 comprises in addition one or more elastic washers 51, of the Belleville type, which are threaded onto the stud 43 between the nut 50 and the primary support plate 30, which ensures elastic anchoring of the primary insulating panels 22 on the load-bearing wall 3.

Furthermore, an insulating plug 52, illustrated on the Figure 4 , is inserted above the retaining device 98 in the recesses 28 provided at the corner zones of four adjacent primary insulating panels 22 so as to ensure continuity of the primary thermally insulating barrier 5 at the level of the retaining device 98. In addition, a closing plate 53, made of wood, illustrated on the Figure 4 makes it possible to ensure flatness of the support surface of the primary waterproof membrane 6. The closing plate 53 is received in countersinks provided at the corner areas of the primary insulating panels 22.

The fixing of the primary waterproof membrane 6 on the primary insulating panels 22 will now be described, according to several examples, with reference to the figures 6 to 14 .

In the embodiment of the Figure 6 , metal anchoring strips 60 are fixed on the cover plates 27 of the insulating panels primaries 22 at the locations of the contours of the rectangular sheets 33. The edges of the rectangular sheets 33 can thus be fixed by welding along the anchoring strips 60. The anchoring strip 60 is fixed in a countersink on the cover plate 27 by any suitable means, for example screws or rivets.

THE figures 6 and 7 also show metal plates 61 which can be fixed to the cover plates 27 of the primary insulating panels 22 at other locations, for example along the edges of the primary insulating panels 22 which are spaced from the contours of the rectangular sheets 33, to provide additional fixing points. A metal plate 61 is fixed in a countersink on the cover plate 27 by any suitable means, for example screws or rivets.

As better visible on the Figure 7 , which is a section at an interface 62 between two primary insulating panels 22, flat areas of a rectangular sheet 33 can be welded transparently onto the metal plates 61.

THE figures 8 and 9 show another embodiment of the primary insulating panels 22, the edges of which have countersinks 63 to receive bridging plates 64, for example made of plywood. The bridging plates 64 are fixed to the cover plates 27 of two primary insulating panels 22 to avoid a separation of the two primary insulating panels 22 at the interface 62 and thus improve the uniformity of the support surface where the membrane rests primary waterproof 6.

On the figures 6 And 8 , the cover plates 27 and the layers of insulating polymer foam 26 are provided with relaxation slots 65 which segment the cover plates 27 and the layers of insulating polymer foam 26 into several parts and thus avoid cracking during cooling .

There Figure 10 shows another embodiment of the primary insulating panels 22, in which the relaxation slots 65 are limited to an area neighboring the anchoring strips 60, as described in the publication FR-A-3001945 .

Thermal protection strips 66, for example made of composite material, are arranged in alignment with the anchoring strips 60, to the right of certain parts of the contours of the rectangular sheets 33, to avoid damaging the cover plate 27 when carrying out the welds.

The tank wall 101 shown on the Figure 12 illustrates an embodiment in which a row of primary insulating panels 22 is superimposed, not on a single row of secondary insulating panels 7, but straddling two rows of secondary insulating panels 7. The elements identical or similar to the elements of the figures 1 to 10 bear the same reference number as these and will only be described to the extent that they differ.

Essentially two modifications were made to the Figure 12 .

On the one hand, the primary retaining members 97 have been separated and offset from the secondary retaining members. The secondary retaining member, not shown, can be made in various ways, for example as the retaining device 98 from which all the elements arranged above the distribution plate 19 will have been removed. distribution of forces 19 and the counterbore 18 intended to receive it can also be removed. The secondary retaining members, not shown, can be in various numbers ranging for example from 2 to 5 per secondary insulating panel 7 and placed for example at the corners of the secondary panels and/or in the gap between two secondary panels, either according to the first direction or according to the second direction. Other embodiments of the secondary retainer are described in WO-A-2013093262 .

The primary retainer 97 can be made in various ways, for example as illustrated in the enlarged view of the Figure 13 or as described in the publication FR-A-2887010 .

On the figure 13 , the primary retaining member 97 comprises a plate 119, for example having a square or circular outline, which is fixed in a countersink formed in the surface of the cover plate 10 facing the layer of insulating polymer foam 11, for example by gluing. The plate 119 has a threaded hole opening into the upper surface of the cover plate 10 into which a stud 143 identical to the stud 43 described above can be screwed.

On the other hand, the entire primary stage of the tank wall, namely the primary thermally insulating barrier 5 and the primary waterproof membrane 6 which it carries, has been offset in both directions of the plane by half the length of a secondary insulating panel 7. Thus, instead of being directly above a secondary retaining member, the primary retaining member 97 is in the center of the cover plate of a secondary insulating panel 7.

Despite this offset, a secondary retaining member still cooperates with the corners of four adjacent secondary insulating panels 7 and a primary retaining member 97 still cooperates with the corners of four adjacent primary insulating panels 22. The magnitude of the offset could be different and the primary retainer 97 could be elsewhere on the cover plate of a secondary insulating panel 7, but preferably at a distance from the raised edges 32 so as not to interfere with them. The amplitude of the offset can be different in the two directions of the plane.

The tank wall 201 sketched on the Figure 14 illustrates an embodiment in which a row of primary insulating panels 22 is superimposed on a row of secondary insulating panels 7, but offset in the first direction by a fraction of the length of an insulating panel, here half of this length. Thus, a primary insulating panel 22 of the primary row straddles two secondary insulating panels 7 of the underlying secondary row. Elements identical or similar to the elements of the figures 1 to 13 bear the same reference number as these and will only be described to the extent that they differ.

In the embodiment sketched on the Figure 14 , the primary insulating panels 22 are retained on the secondary waterproof membrane, not shown, by retaining members arranged in the middle of the sides of the primary insulating panels 22. Thus, the primary retaining member 97 arranged in the center of the cover plate of the secondary insulating panel 7 cooperates with two primary insulating panels 22 of the primary row and is located at mid-width of the primary row. Furthermore, at the corners of the secondary insulating panels 7 there are secondary retaining members 92, as in the previous embodiments. The secondary retainer 92 carries a primary retainer 91. The secondary retainer 92 and the primary retainer 91 which it carries can be made similarly to the retainer 98 or differently. Unlike in there figure 1 , the primary retaining member 91 cooperates here with only two primary insulating panels 22, at the middle of one side of these primary insulating panels 22.

To facilitate access to the primary retaining member 91, the shape of the primary insulating panels 22 can be configured to provide an access chimney 93. In this case, the chimney 93 is closed after installation of the member primary retainer 91, for example with a polyurethane foam plug covered with a rigid plate, for example plywood (not shown).

We have described above a primary waterproof membrane in which the undulations are continuous at the level of the intersections between the two series of undulations. The primary waterproof membrane can also have two series of mutually perpendicular undulations with discontinuities of certain undulations at the intersections between the two series. In this case the interruptions are distributed alternately in the first series of undulations and the second series of undulations and, within a series of undulations, the interruptions of one undulation are offset relative to the interruptions of one undulation adjacent parallel. This offset can be equal to the spacing between two parallel undulations.

In reference to the Figure 11 , a cutaway view of an LNG ship 70 shows a watertight and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary waterproof barrier intended to be in contact with the LNG contained in the tank, a secondary waterproof barrier arranged between the primary waterproof barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary waterproof barrier and the secondary waterproof barrier and between the secondary waterproof barrier and the double hull 72.

In a manner known per se, loading/unloading pipes 73 arranged on the upper deck of the ship can be connected, by means of appropriate connectors, to a maritime or port terminal to transfer a cargo of LNG from or to the tank 71.

There Figure 11 represents 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 mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can connect to the loading/unloading pipes 73. The adjustable mobile arm 74 adapts to all LNG carrier templates. A connection pipe not shown extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG tanker 70 from or to the onshore installation 77. This includes 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 onshore installation 77 over a long distance, for example 5 km, which makes it possible to keep the LNG ship 70 at a long 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 on-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 quite obvious that it is in no way limited and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention, defined by the claims.

The use of the verb “include”, “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.

In the claims, any parenthetical reference sign shall not be construed as a limitation of the claim.

Claims (24)

1. A thermally-insulating sealed tank incorporated in a supporting structure, the tank comprising a tank wall (1, 101, 201) fixed onto a supporting wall (3) of the supporting structure,

   the tank wall comprising a primary sealed membrane (6) intended to be in contact with a product contained in the tank, a secondary sealed membrane (4) arranged between the primary sealed membrane and the supporting wall, a primary insulating barrier (5) arranged between the primary sealed membrane the secondary sealed membrane and a secondary insulating barrier (2) arranged between the secondary sealed membrane and the supporting wall,

   wherein the secondary insulating barrier comprises a plurality of secondary rows (A, B, C) parallel to a first direction, a secondary row comprising a plurality of juxtaposed parallelepipedal secondary insulating panels (7), the secondary rows being juxtaposed in a second direction at right angles to the first direction according to a repeated pattern,

   wherein the secondary sealed membrane comprises a plurality of strakes (21) made of an alloy with low expansion coefficient parallel to the first direction, a strake comprising a flat central portion resting on a top surface of the secondary insulating panels and two raised edges protruding toward the interior of the tank with respect to the central portion, the strakes being juxtaposed in the second direction according to a repeated pattern and welded together tightly at the raised edges, anchoring wings anchored to the secondary insulating panels and parallel to the first direction being arranged between the juxtaposed strakes to hold the secondary sealed membrane on the secondary insulating barrier,

   wherein the size of the repeated pattern of the secondary rows (A, B, C) is an integer multiple of the size of a strake (21) in the second direction,

   wherein the supporting wall supports secondary retaining members (98, 92) disposed at the interfaces between the secondary rows and cooperating with the secondary insulating panels (7) to hold the secondary insulating panels on the supporting wall, wherein the primary insulating barrier (5) comprises a plurality of primary rows parallel to the first direction, a primary row comprising a plurality of juxtaposed parallelepipedal primary insulating panels (22), the primary rows being juxtaposed in the second direction according to a repeated pattern, the size of the repeated pattern of the primary rows being equal to the size of the repeated pattern of the secondary rows (A, B, C) in the second direction,

   wherein the primary retaining members (98, 91, 97) are disposed at the interfaces between the primary rows and cooperate with the primary insulating panels to hold the primary insulating panels on the secondary sealed membrane,

   wherein the or each primary row is superposed straddling two secondary rows (A, B, C) and wherein the primary retaining members (97) are supported by the secondary insulating panels (7),

   wherein the primary sealed membrane has first corrugations (56) parallel to the first direction and disposed according to a repeated pattern in the second direction and flat portions situated between the first corrugations and resting on a top surface of the primary insulating panels,

   wherein the size of the repeated pattern of the primary rows is an integer multiple of the size of the repeated pattern of the first corrugations,

   the primary sealed membrane comprising a plurality of rows of metal sheets parallel to the first direction, a row of metal sheets comprising a plurality of rectangular metal sheets (33) welded together tightly by edge zones (59), the rows of metal sheets being juxtaposed in the second direction and welded together tightly, the size of a row of metal sheets in the second direction being equal to an integer multiple of the size of the repeated pattern of the primary rows,

   characterized in that the rows of metal sheets are offset in the second direction with respect to the primary rows such that the welded joins between the rows of metal sheets are situated at a distance from the interfaces between the primary rows, and that a primary retaining member comprises a plate fixed to a cover plate of the secondary insulating panel under the secondary sealed membrane and a rod attached to said plate and passing tightly through the secondary sealed membrane toward the primary insulating barrier (5).
2. The tank as claimed in claim 1, wherein the primary rows are offset in the second direction by a half of the size of the repeated pattern of the secondary rows with respect to the secondary rows (A, B, C).
3. The tank as claimed in claim 1 or 2, wherein the interfaces between the primary insulating panels within the or each primary row are offset in the first direction with respect to the interfaces between the secondary insulating panels within the two secondary rows on which the primary row is superposed, and wherein the primary retaining members (97) are supported by the secondary insulating panels (7) at a distance from the edges of the secondary insulating panels.
4. The tank as claimed in any one of claims 1 to 3, wherein the first corrugations (56) are spaced apart by a first regular spacing (58) in the second direction.
5. The tank as claimed in claim 4, wherein the size of a strake (21) in the second direction is an integer multiple of said first regular spacing (58).
6. The tank as claimed in any one of claims 1 to 5, wherein a primary row comprises a plurality of parallelepipedal primary insulating panels (22) juxtaposed according to a repeated pattern and a row of metal sheets of the primary sealed membrane comprises a plurality of rectangular metal sheets (33) juxtaposed according to a repeated pattern, the size of the repeated pattern of the rectangular metal sheets being equal to an integer multiple of the size of the repeated pattern of the primary insulating panels in the first direction.
7. The tank as claimed in claim 6, wherein the edges of the rectangular metal sheets (33) are offset in the first direction with respect to the edges of the primary insulating panels (22) parallel to the second direction, such that the welded joins between the rectangular metal sheets are situated at a distance from the edges of the primary insulating panels parallel to the second direction.
8. The tank as claimed in any one of claims 1 to 7, wherein the primary insulating panels (22) and/or the secondary insulating panels (7) have a square form.
9. The tank as claimed in any one of claims 1 to 8, wherein the primary sealed membrane (6) also has second corrugations (55) parallel to the second direction and disposed according to a repeated pattern in the first direction, the flat portions being situated between the first corrugations and between the second corrugations.
10. The tank as claimed in claim 9, wherein the second corrugations (55) parallel to the second direction are spaced apart by a second regular spacing (57) in the first direction.
11. The tank as claimed in claims 4 and 10 taken in combination, wherein the first regular spacing (58) is equal to the second regular spacing (57).
12. The tank as claimed in any one of claims 9 to 11, wherein the first and second corrugations (55, 56) are continuous at the intersections between first and second corrugations.
13. The tank as claimed in claims 9 to 11, wherein the first and second corrugations are discontinuous at the intersections between the first and second corrugations.
14. The tank as claimed in any one of claims 9 to 11, wherein a rectangular metal sheet (33) of the primary sealed membrane has a size in the first direction substantially equal to an integer multiple of the size of the repeated pattern of the second corrugations.
15. The tank as claimed in any one of claims 1 to 14, wherein a primary insulating panel (22) comprises a bottom plate (23) resting against the primary sealed membrane (4), an intermediate plate (25) disposed between the bottom plate and a cover plate (27), a first layer of insulating polymer foam (24) sandwiched between the bottom plate and the intermediate plate and a second layer of insulating polymer foam (26) sandwiched between the intermediate plate and the cover plate (27).
16. The tank as claimed in any one of claims 1 to 15, wherein the primary sealed membrane (5) is held on the primary insulating barrier by anchoring means, the anchoring means comprising metal anchoring strips (60) fixed onto the primary insulating panels at locations corresponding to outlines of the rectangular metal sheets (33) and to which edge zones (59) of the rectangular metal sheets can be welded.
17. The tank as claimed in claim 16, wherein a primary insulating panel comprises relaxation slits (65) hollowed out in a thicknesswise direction of the primary insulating panel and emerging on a cover plate (27) of the primary insulating panel and wherein a metal anchoring strip (60) comprises several aligned segments, fixed onto the cover plate (27) and separated by the relaxation slits (65).
18. The tank as claimed in any one of claims 1 to 17, wherein the primary sealed membrane (5) is held on the primary insulating barrier by anchoring means, the anchoring means comprising metal inserts (61) fixed onto the primary insulating panels (22) at locations corresponding to edge zones of the primary insulating panels at a distance from the outlines of the rectangular metal sheets and to which central zones of the rectangular metal sheets (33) can be welded.
19. The tank as claimed in claim 18, wherein a primary insulating panel comprises relaxation slits (65) hollowed out in a thicknesswise direction of the primary insulating panel and emerging on a cover plate (27) of the primary insulating panel and wherein the metal inserts (61) are fixed onto the cover plate (27) between the relaxation slits (65).
20. The tank as claimed in any one of claims 1 to 19, wherein the primary insulating barrier comprises a bridging element (64) fixed to the top surfaces of at least two adjacent primary insulating panels (22) to avoid a separation of the two primary insulating panels (22).
21. The tank as claimed in claim 20, wherein said primary insulating panels (22) having facings (63) on edges of the top surface to receive said bridging element (64).
22. A ship (70) for transporting a fluid, the ship comprising a double hull (72) and a tank (71) as claimed in any one of claims 1 to 21 disposed in the double hull (72).
23. A transfer system for a fluid, the system comprising a ship (70) as claimed in claim 22, insulated pipelines (73, 79, 76, 81) arranged so as to link the tank (71) installed in the hull of the ship to a floating or onshore storage installation (77) and a pump for driving a fluid through the insulated pipelines from or to the floating or onshore storage installation to or from the tank of the ship.
24. A method for loading or offloading a ship (70) as claimed in claim 22, wherein a fluid is conveyed through insulated pipelines (73, 79, 76, 81) from or to a floating or onshore storage installation (77) to or from the tank of the ship (71).

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