FR3115093A1 - Watertight and thermally insulated tank - Google Patents

Abstract

The invention relates to a wall (1) of a sealed and thermally insulating tank for storing a liquefied gas, said wall (1) comprising at least one thermally insulating barrier (6) and a sealed membrane (8) which is anchored to said thermally insulating barrier (6) and is intended to be in contact with the liquefied gas, the thermally insulating barrier (6) comprising a first insulating panel (7) and a second insulating panel (7) arranged along a first edge of the first insulating panel, the first and second insulating panels (7) being respectively equipped with at least one first anchoring element (20) and at least one second anchoring element (20) on which the waterproof membrane (8) is welded; the waterproof membrane (8) comprising undulations (17, 18) separated from each other by flat portions (19) and in which at least one of the flat portions (19) is arranged astride the first and the second insulating panels (7) and is welded on the one hand to the first anchoring element (20) and on the other hand to the second anchoring element (20). Figure to be published: 2

Description

Watertight and thermally insulated tank

The invention relates to the field of sealed and thermally insulating tanks for the storage and/or transport of a liquefied gas, such as tanks for the transport of Liquefied Petroleum Gas (also called LPG) having for example a temperature between between -50°C and 0°C, or for transporting Liquefied Natural Gas (LNG) at approximately -163°C at atmospheric pressure.

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 gas or to receive liquefied gas used as fuel for the propulsion of the floating structure.

Technology background

Known in the state of the art is a sealed and thermally insulating vessel comprising a vessel wall retained on a supporting structure, the vessel wall including, in the direction of the thickness from the outside towards the inside of the vessel , a secondary thermally insulating barrier retained on the supporting structure, a secondary waterproof membrane retained on the secondary thermally insulating barrier, a primary thermally insulating barrier retained on the secondary waterproof membrane and a corrugated primary waterproof membrane retained on the primary thermally insulating barrier. Such a sealed and thermally insulating tank can in particular be used in the transport of liquefied gas, such as liquefied natural gas (LNG), in particular on board a floating structure, such as a ship.

It is known to produce the primary waterproof membrane by assembling a plurality of sheets which have undulations, advantageously perpendicular to each other. The corrugations give the primary sealed membrane a flexibility allowing it to deform under the effect of thermal and mechanical stresses and in particular those generated by the liquefied gas stored in the tank and those related to the deformation of the supporting structure. The primary waterproof membrane is anchored to the insulating panels of the primary thermally insulating barrier. To do this, each sheet is arranged astride several insulating panels of the primary thermally insulating barrier. Furthermore, the sheets are welded to each other along their edges and are also welded along their edges to anchoring elements which are attached to said insulating panels. More specifically, the sheets are welded to anchoring elements which are arranged along the edges of the sheets, on either side of each corrugation.

The applicant has found that in a tank of the aforementioned type, the undulations of the primary sealed membrane were not stressed uniformly. In particular, insofar as the primary thermally insulating barrier is discontinuous, that is to say that it consists of insulating panels juxtaposed to each other, its behavior is not homogeneous when the load-bearing structure deforms and / or under the effect of thermal and mechanical stresses generated by the liquefied gas stored in the tank. Thus, the applicant has found that the undulations which are arranged in a zone straddling a first anchoring element fixed to a first insulating panel and a second anchoring element fixed to a second insulating panel are stressed in a greater way than others. However, it is important to ensure that the stresses are distributed as evenly as possible between the undulations of the primary waterproof membrane, in particular with a view to optimizing the life of the primary waterproof membrane.

Summary

One idea underlying the invention is to propose a sealed and thermally insulating tank in which the stresses undergone by the primary sealed membrane are more evenly distributed between the undulations thereof.

According to one embodiment, the invention relates to a wall of a sealed and thermally insulating tank for storing a liquefied gas, said wall comprising at least one thermally insulating barrier and a sealed membrane which is anchored to said thermally insulating barrier and is intended to be in contact with the liquefied gas, the thermally insulating barrier comprising a first insulating panel and a second insulating panel arranged along a first edge of the first insulating panel, the first and second insulating panels being respectively equipped with at at least one first anchoring element and at least one second anchoring element to which the waterproof membrane is welded; the waterproof membrane comprising corrugations separated from each other by flat portions and in which at least one of the flat portions is arranged astride the first and the second insulating panels and is welded on the one hand to the first element of anchoring and on the other hand to the second anchoring element.

Thus, the plane portion of the waterproof membrane which is arranged astride between the adjacent insulating panels, performs a function of mechanical connection between the insulating panels. This prevents the mutual spacing of said insulating panels and contributes to more evenly distributing the deformation of the load-bearing structure over the primary thermally insulating barrier. Indeed, the behavior of the assembly consisting of the thermally insulating barrier and the waterproof membrane is here dictated by the fact that the insulating panels have overall a lower stiffness than that of the waterproof membrane. It is therefore the deformations of the waterproof membrane that condition those of the insulating panels. This therefore makes it possible to stress the undulations of the waterproof membrane in a more homogeneous manner.

According to embodiments, such a vessel wall may comprise one or more of the following characteristics.

According to one embodiment, the stiffness of the first and second insulating panels is less than the stiffness of a flat portion of the waterproof membrane. This ensures that the deformations of the thermally insulating barrier are imposed by the deformations of the waterproof membrane. For example, the stiffness of the first and second insulating panels is three times less than the stiffness of a flat portion of the waterproof membrane.

According to one embodiment, the first and the second anchoring elements are arranged so that their centers are separated from each other by a distance of between 8 and 25 cm and preferably between 10 and 20 cm.

According to one embodiment, the first anchoring elements are arranged at least along the first edge of the first insulating panel and the second anchoring elements are arranged at least along the edge of the second panel which is adjacent to the first edge of the first insulation board.

According to one embodiment, the waterproof membrane comprises first corrugations extending parallel to a first direction and second corrugations extending parallel to a second direction, the first direction being perpendicular to the second direction.

According to one embodiment, the undulations are continuous, that is to say without interruption.

According to one embodiment, the first and second insulating panels have a parallelepipedal shape and each have two opposite edges parallel to the first direction and two opposite edges parallel to the second direction.

According to one embodiment, the first and second insulating panels are respectively equipped with several first anchoring elements and several second anchoring elements and several of the flat portions are arranged astride between the first and the second insulating panels and are each welded to one of the first anchoring elements and to one of the second anchoring elements.

According to one embodiment, the waterproof membrane is welded to the at least one first anchoring element and to the at least one second anchoring element by a plug weld or by a transparency weld.

According to one embodiment, the at least one first anchoring element and the at least one second anchoring element each comprise a metal plate which is fixed in a counterbore made in one of the first and second insulating panels.

According to one embodiment, the waterproof membrane comprises a plurality of corrugated metal sheets, each corrugated metal sheet having edges that are each lap welded to an edge of an adjacent corrugated metal sheet.

According to one embodiment, at least one of the flat portions which straddles the first and the second insulating panels and is welded to the first and to the second anchoring elements is made in one piece, that is i.e. in a single corrugated metal sheet.

According to one embodiment, the flat portion which straddles the first and second insulating panels and is welded to the first and to the second anchoring elements belongs to a first edge portion of one of the corrugated metal sheets; the first edge portion being covered by a second edge portion of an adjacent corrugated metal sheet, the first edge portion being welded to the first anchor member by means of a first plug weld and being welded to the second anchor member by means of a second plug weld, the second edge portion covering the second plug weld and at least a part of the first plug weld and being lap welded in a sealing manner to the first edge portion .

According to one embodiment, the flat portion which is arranged astride the first and the second insulating panels and is welded to the first and to the second anchoring elements is produced by a first and a second edge portions of two corrugated metal sheets which are lap welded to each other.

According to one embodiment, the first edge portion is intended to be covered by the second edge portion, the first edge portion being welded to the first anchoring member by means of a weld, for example by plug, the second edge portion being welded to the second anchoring member, covering at least part of the weld and being bead welded in a leaktight manner to the first edge portion.

According to one embodiment, the first and second insulating panels each have thermal protection elements facing the edges of the corrugated metal sheets.

According to one embodiment, the thermal protection elements are formed from an aluminum plate or a composite film comprising at least one aluminum sheet associated with at least one glass fiber mat.

According to one embodiment, the thermally insulating barrier comprises a third insulating panel arranged along a second edge of the first insulating panel, a fourth insulating panel arranged along a third edge of the first insulating panel and a fifth insulating panel arranged along a fourth edge of the first insulating panel, the third, fourth and fifth insulating panels being respectively equipped with third, fourth and fifth anchoring elements, the waterproof membrane comprising planar portions arranged astride the first and the third insulating panels which are each welded on the one hand to one of the first anchoring elements and on the other hand to one of the third anchoring elements, flat portions arranged astride the first and the fourth insulating panels which are each welded on the one hand to one of the first anchoring elements and on the other hand to one of the fourth anchoring elements and to the flat portions nes arranged astride the first and fifth insulating panels which are each welded on the one hand to one of the first anchoring elements and on the other hand to one of the fifth anchoring elements.

According to one embodiment, the first anchoring elements are arranged at least along the first edge of the first insulating panel and the second anchoring elements are arranged at least along the edge of the second panel which is adjacent to the first edge of the first insulation panel.

According to one embodiment, the first anchoring elements are arranged along the first, second, third and fourth edges of the first insulating panel.

According to one embodiment, the anchoring elements of each insulating panel are arranged along the four edges of said insulating panel.

According to one embodiment, the first and the second edges of the first insulating panel are contiguous, the wall comprising a sixth panel which is arranged along an edge of the second insulating panel and along an edge of the third insulating panel and which is equipped with sixth anchoring elements.

According to one embodiment, one of the flat portions is arranged astride the first, the second, the third and the sixth insulating panels and is fixed to one of the first anchoring elements, to one of the second anchors and one of the third anchors and one of the sixth anchors.

According to one embodiment, the first and the second insulating panels have relaxation slots opposite the corrugations of the waterproof membrane, and more particularly opposite each of the corrugations of the waterproof membrane which are opposite of said first and second insulating panels.

According to one embodiment, the at least one first anchoring element and the at least one second anchoring element are respectively placed on an outer portion of the first insulating panel and of the second insulating panel delimited by at least one relaxation slots of the first or second insulating panel.

According to one embodiment, each relaxation slot adjacent to one of the edges of the first or of the second panel delimits with the relaxation slots which are perpendicular to it, a plurality of edge zones, which are each equipped with a first or second anchor.

According to one embodiment, the waterproof membrane is a primary waterproof membrane and the thermally insulating barrier is a primary thermally insulating barrier, the wall further comprises a secondary thermally insulating barrier retained against a load-bearing structure and a secondary waterproof membrane fixed to the barrier secondary thermally insulating barrier and disposed between the secondary thermally insulating barrier and the primary thermally insulating barrier.

According to one embodiment, the invention relates to a sealed and thermally insulating tank comprising an aforementioned wall.

A tank according to one of the aforementioned embodiments can be part of an onshore storage installation, for example for storing LNG or be installed in a floating, coastal or deep-water structure, in particular an ethane or LNG carrier, a floating storage and regasification unit (FSRU), floating production and remote storage unit (FPSO) and others. In the case of a floating structure, the tank may be intended to receive liquefied natural gas serving as fuel for the propulsion of the floating structure.

According to one embodiment, the invention provides a vessel for the transport of a fluid which comprises a hull, such as a double hull, and a aforementioned tank disposed in the hull.

According to one embodiment, the invention also provides a method for loading or unloading such a ship, in which a fluid is routed 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 terrestrial storage installation and a pump for driving a flow of fluid through the insulated pipes from or to the floating or onshore storage facility to or from the vessel's tank.

Brief description of figures

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 accompanying drawings.

There is a schematic sectional view of the multilayer structure of a vessel wall.

There is a partial cutaway view of a vessel wall.

There is a perspective view of a corrugated metal sheet of a primary waterproof membrane.

There is a partial top view of the primary thermally insulating barrier.

There is a partial cross-sectional view of a primary anchor device according to one embodiment.

There is a cutaway schematic representation of a ship comprising a liquefied natural gas storage tank and a loading/unloading terminal for this tank.

There is a schematic sectional view illustrating the overlap between the edges of two adjacent corrugated metal sheets in the embodiment of Figures 2 to 4.

There is a partial cutaway view of a vessel wall similar to that of the according to another embodiment.

There is a schematic sectional view illustrating the overlap between the edges of two adjacent corrugated metal sheets in the embodiment of the .

There is a schematic sectional view illustrating the overlap between the edges of two adjacent corrugated metal sheets according to a variant of the embodiment of the .

There is a schematic sectional view illustrating the overlap between the edges of two adjacent corrugated metal sheets according to another variant of the embodiment of the .

There is a partial cutaway view of a vessel wall according to another alternative embodiment.

There is a partial cutaway view of a vessel wall similar to those of Figures 2 and 8 according to yet another alternative embodiment.

There is a detailed cross-sectional view of an anchor according to the embodiment of the .

There is a perspective view of an insulating panel according to another alternative embodiment.

There illustrates an anchoring element intended to be fixed to the insulation panel of the .

By convention, the terms “external” and “internal” are used to define the relative position of one element in relation to another, by reference to the exterior and the interior of the tank.

On the , there is shown schematically the multilayer structure of a wall 1 of a sealed and thermally insulating tank for storing a liquefied gas. Each wall 1 comprises, from the outside towards the inside of the tank, a secondary thermally insulating barrier 2 comprising secondary panels 3 anchored to a supporting structure 4, a secondary waterproof membrane 5 resting against the secondary thermally insulating barrier 2, a primary thermally insulating barrier 6 comprising primary panels 7 resting against the secondary waterproof membrane 5 and anchored to the secondary panels 3 and a primary waterproof membrane 8 which rests against the primary thermally insulating barrier 6 and which is intended to be in contact with the liquefied gas content in the tank.

The load-bearing structure 4 can in particular be formed by the hull or the double hull of a ship. The support structure 4 comprises a plurality of walls defining the general shape of the tank, usually a polyhedral shape.

In relation to the , it is observed that the secondary thermally insulating barrier 2 comprises a plurality of secondary panels 3. The secondary panels 3 are anchored to the supporting structure 4 by means of secondary anchoring devices, not shown. The secondary panels 3 have a generally parallelepipedic shape and are arranged in secondary rows parallel to each other. By way of example, in the illustrated embodiment, the secondary panels 3 have a layer of insulating polymer foam 9 sandwiched between an outer plate 10 and an inner plate 11. The outer plate 10 and the inner plate 11 are, for example, plywood and glued to the layer of insulating polymer foam 9. The insulating polymer foam may in particular be a polyurethane-based foam, optionally reinforced with glass fibers. The structure of the secondary panel 3 is described above by way of example. Also, in another embodiment, the secondary panels 3 are likely to have another general structure, for example that described in document WO2012/127141. In another embodiment, the secondary thermally insulating barrier 2 comprises secondary panels 3 having at least two different types of structure, for example the two aforementioned structures, depending on their location in the tank.

The secondary waterproof membrane 5, partially illustrated on the , comprises a continuous layer of strakes 12, metal, having two raised edges, parallel. The strakes 12 are welded by their raised edges to parallel welding supports which are housed in grooves formed in the internal plate 11 of the secondary panels 3. The strakes 12 are, for example, made of Invar®: that is to say that is, 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 alloys of iron and manganese whose coefficient of expansion is typically of the order of 7 to 9.10-6 K-1. In another embodiment, the metal membrane has waves and can, for example, be made of the same alloys as the strakes.

Furthermore, the primary thermally insulating barrier 6 comprises a plurality of primary panels 7 which are anchored to the secondary thermally insulating barrier 2 by means of primary anchoring devices, as described later in relation to the . The primary panels 7 have a generally parallelepipedal shape and are arranged in rows which are parallel to each other.

The primary panels 7 may have a multilayer structure analogous to the structure of the secondary panels 3. Thus, according to the embodiment shown, the primary panels 7 comprise successively, in the thickness direction of the wall 1, an outer plate 13, for example in plywood, a layer of insulating polymer foam 14 and an internal plate 15, for example in plywood. The insulating polymer foam layer 14 is, for example, a polyurethane-based foam, optionally reinforced with glass fibers. The structure of the primary panel 7 is described above by way of example.

As illustrated on the , the outer plate 13 of the primary panels 7 has grooves which receive the raised edges of the strakes 12 of the secondary waterproof membrane 5.

Furthermore, the primary waterproof membrane 8 is obtained by assembling a plurality of corrugated metal sheets 16, one of which is shown on the . The corrugated metal sheets 16 are, for example, made of stainless steel or aluminum. The primary waterproof membrane 8 has a thickness comprised between 1 and 2 mm and preferably comprised between 1.2 and 1.8 mm. Each corrugated metal sheet 16 has two series of mutually perpendicular corrugations 17, 18. The undulations 17, 18 are separated from each other by planar portions 19 of rectangular and advantageously square shape. The corrugated metal sheets 16 are rectangular, and preferably have width and length dimensions which are integer multiples of a spacing between corrugations and also integer multiples of the dimensions of the primary panels 7. In this embodiment , the undulations 17, 18 are continuous and cross each other. In a variant embodiment not shown, each of the corrugations 17, 18 have corrugated portions spaced apart from each other by flat portions. The undulations are then discontinuous. Advantageously, the corrugated portions do not intersect with each other.

As shown on the , the corrugated metal sheets 16 of the primary waterproof membrane 8 are welded to anchoring elements 20. According to one embodiment, the anchoring elements 20 are metal plates which are housed in counterbores formed in the internal plate 15 and fixed thereto by gluing and/or by means of fixing elements, such as rivets or screws for example. The corrugated metal sheets 16 are arranged astride several primary panels 7 and are arranged so that their edges as well as their corrugations 17, 18 are oriented parallel or perpendicular to the edges of the primary panels 7.

The corrugated metal sheets 16 of the primary waterproof membrane 8 are anchored along the edges of each of the primary panels 7. Each flat portion 19 of the primary waterproof membrane 8 which straddles at least two primary panels 7 is fixed, on the one hand, to an anchoring element 20 which is fixed to one of the primary panels 7 and, on the other hand, to another anchoring element 20 which is fixed to the other of the adjacent primary panels 7 . Advantageously, the two anchoring elements 20 to which one of the flat portions 19 is welded and respectively fixed to two adjacent primary panels 7 are arranged so that their centers are separated from each other by a distance between 8 and 25 cm and preferably between 10 and 20 cm. This makes it possible to limit the level of stresses likely to be exerted on the welds of the corrugated metal sheets 16 to the anchoring elements 20, in particular due to the phenomena of deformation of the hull by the swell or by sloshing.

Thus, in this embodiment, the anchoring of the primary waterproof membrane 8 is not carried out at the level of the edges of corrugated metal sheets 16 but in flat portions corresponding to the edges of each of the primary panels 7. The flat portions 19 arranged astride between at least two adjacent primary panels 7, thus ensure a function of mechanical connection between the primary panels 7. This prevents the mutual separation of the primary panels 7 and contributes to distributing more evenly the deformation of the supporting structure 4 on the primary thermally insulating barrier 6. We also observe that certain flat portions 19 which straddle four corner zones of four adjacent primary panels 7 are anchored to anchoring elements 20 belonging to each of the four adjacent primary panels 7 .

Moreover, as illustrated in the , each primary panel 7 has relaxation slots 21 which each extend opposite a respective corrugation 17, 18 of the primary waterproof membrane 8. These relaxation slots 21 make it possible to take full advantage of the corrugations 17, 18 since they allow the primary waterproof membrane 8 to deform without imposing excessive mechanical stresses on the primary panels 7.

In the embodiment shown, each primary panel 7 faces three corrugations 17 extending parallel to a first direction and three corrugations 18 extending parallel to a second direction perpendicular to the first direction. Also, each primary panel 7 comprises three relaxation slots 21 extending parallel to the first direction and each arranged facing one of the undulations 17 and three relaxation slots 21 extending parallel to the second direction and each arranged in next to one of the corrugations 17, 18. The relaxation slots 21 are therefore spaced apart by a pitch corresponding to the pitch between the corrugations 17, 18 parallel to said relaxation slots 21. However, each relaxation slot 21 adjacent to the one of the edges of a primary panel 7 is separated from said edge by a distance corresponding substantially to half of a pitch between the undulations parallel to said relaxation slot. Each relaxation slot 21 adjacent to one of the edges of a primary panel 7 delimits with the relaxation slots which are perpendicular to it, a plurality of edge zones, which are each equipped with an anchoring element 20.

The corrugated metal sheets 16 of the primary waterproof membrane 8 are fixed by welding to the anchoring elements 20.

According to a first embodiment shown in the , the corrugated metal sheets 16 are anchored to the anchoring elements 20 by means of plug welds 22. To do this, the corrugated metal sheets 16 have at least one through hole which is in the form of a slot in the embodiment shown. but is likely to have any other shape and in particular circular. The through hole is made in line with each anchoring element 20. Each of said holes is filled with welds to ensure the connection between the primary waterproof membrane 8 and the anchoring elements 20.

According to another embodiment, the corrugated metal sheets 16 are anchored to the anchoring elements 20 by means of welding by transparency, that is to say by using a laser source without adding material. In this case the corrugated metal sheets 16 do not have any holes.

Furthermore, the corrugated metal sheets 16 of the primary waterproof membrane 8 are overlap welded along their edges.

In the embodiment of Figures 2 to 4, the edges of the corrugated metal sheets 16 are offset from the edges of the primary panels 7. Also, as shown in the , the internal plate of the primary panels 7 advantageously comprises, along the edges of the corrugated metal sheets 16, thermal protection elements 23. The thermal protection elements 23 are, for example, formed of an aluminum plate or of a composite film comprising at least one aluminum sheet associated with at least one mat of glass fibers. The thermal protection elements 23 are advantageously housed in counterbores provided in the inner plate 15 of the primary panels 7 and are arranged in each interval between an edge and a relaxation slot 21 or between two relaxation slots 21. The thermal protection elements 23 are fixed to the inner plate 15 of the primary panels 7 by gluing and/or stapling. The thermal protection elements 23 make it possible to protect the primary panels 7 and in particular their layer of insulating polymer foam 14 against temperatures liable to degrade them during the operations of welding the metal sheets together along their edges.

In the embodiment shown in the , the undulations 17, 18 are not arranged symmetrically with respect to the two median axes, illustrated in phantom on the . Each central axis is parallel to two opposite edges of the corrugated metal sheet 16 and divides it into two equal portions. More particularly, each corrugation 17, 18 which is adjacent and parallel to one of the edges intended to be covered by an edge of another corrugated metal sheet 16 is placed at a greater distance d1 or d2 from the adjacent edge than the distance d3, d4 between the corrugation 17, 18, which is adjacent and parallel to the opposite edge which is intended to cover an edge of an adjacent metal sheet, and said opposite edge. This makes it possible to increase the width of the overlap zones between the edges of the adjacent corrugated metal sheets 16 .

As shown schematically in the , in the areas of overlap between two adjacent metal sheets 16 which are arranged astride between two adjacent primary panels 7, it is the edge of the corrugated metal sheet 16 which is covered by an adjacent edge of another adjacent metal sheet which is welded to the two anchoring elements belonging respectively to one and the other of the two adjacent primary panels 7. It is thus understood that by increasing the width of the overlap, as proposed above in relation to the , at least a portion of the plug welds 22 is covered. This makes it possible to limit the length of plug welds 22 critical for the sealing of the primary sealed membrane 8 and the sealing of which must, as such, be ensured. Alternatively, the plug weld 22 can be replaced by a transparency weld and a lap weld on certain anchors 20.

According to an embodiment not shown, in order to limit the number of thermal protection elements 23 to be installed, the anchoring elements 20 which are arranged close to an edge of one of the corrugated metal sheets 16 extend, along the edge of the corrugated metal sheet 16, from the edge of the primary panel 7 to the relaxation slot 21 adjacent to and parallel to said edge of the primary panel 7. Thus, in this zone, said anchoring element 20 serves to both the anchoring of the primary waterproof membrane 8 and the thermal protection of the primary panels 7 during lap welding of the edges of corrugated metal sheets 16 to each other.

According to another embodiment, not shown, the corrugated metal sheets 16 of the primary waterproof membrane 8 are also anchored to the primary thermally insulating barrier 6 at their edges. In this case, the thermal protection elements 23, illustrated in the , are replaced by metal anchors.

As shown on the , the primary panels 7 include recesses 24 at their corners, so that their outer plate 13 protrudes with respect to their layer of insulating polymer foam 14 and to their inner plate 15. Thus, the outer plate 13 forms at the level of the corners of the primary panels 7 a support zone 25 intended to cooperate directly or indirectly with a support plate 26 of a primary anchoring device 27. In addition, in the embodiment shown, a wedge 28 is added on the outer plate 13, said wedge 28 having a shape similar to that of the bearing zone 25 and cooperating with the bearing plate 26 to anchor the primary panel 7. Each primary anchoring device 27 cooperates with four zones of support 25 belonging respectively to the corners of four adjacent primary panels 7. Each primary anchoring device 27 comprises a pin 29 which protrudes from one of the secondary panels 3, a support plate 26 which is fixed to the end of the pin 29 and which bears against the four zones of support 25 of the four adjacent primary panels 7 so as to retain them against the secondary thermally insulating barrier 2. The support plate 26 comprises a bore threaded onto the stud 29. A nut 30 cooperates with a threaded end of the stud 29 so as to ensuring the fixing of the support plate 26. In addition, according to an advantageous embodiment, Belleville washers are threaded onto the stud 29, between the nut 30 and the support plate 26, which makes it possible to ensure an elastic anchoring of the primary panels 7 on the secondary thermally insulating barrier 2.

The stud 29 is fixed to a base 31 which is itself fixed to the internal plate 11 of the secondary panels 3. To do this, the base 31 comprises, for example, a thread which cooperates with a complementary threaded end of the stud 29. Furthermore, the internal plate 11 of the secondary panels 3 has a recess in which the base 31 is housed. The recess has an internal section presenting a first diameter and an external section presenting a second diameter greater than the first diameter so as to shoulder. The base 31 has a shape complementary to that of the recess. Thus, the internal face of the base 31 is flush with the internal face of the internal plate 11 of the secondary panels 3 so as to form a flat support surface for the secondary waterproof membrane 5. In addition, the base 31 has an external section having a larger diameter than its internal section so that the external section of said base abuts against the shoulder of the recess. The base 31 is also glued to the secondary panel 3.

Furthermore, the stud 29 passes through in a sealed manner an orifice made in the secondary sealed membrane 5.

The embodiment shown in the differs from the embodiment described above in that the corrugated metal sheets 16 of the primary waterproof membrane 8 are substantially aligned with respect to the rows of primary panels 7. In other words, the edges of the corrugated metal sheets 16 run along certain edges of primary panels 7. To do this, the corrugated metal sheets 16 preferably have width and length dimensions which are equal to whole values or whole multiples of a spacing between corrugations and also whole multiples of the dimensions primary panels 7, disregarding the dimensions of the overlap zones between the corrugated metal sheets 16 adjacent. Thus, in the embodiment illustrated in the , two of the edges of each corrugated metal sheet 16 have a length which is substantially equal to three times the dimension of one side of the primary panels 7 while the second other edges have a length which is substantially equal to the dimension of one side primary panels 7.

There illustrates an overlap zone between two adjacent corrugated metal sheets 16 in the embodiment of the . In this embodiment, the two edge portions of the adjacent corrugated metal sheets 16 which are arranged overlapping one above the other are welded to the anchoring elements 20 by means of a plug weld 22 or by transparency. The two edge portions are welded to each other by means of a weld, for example a lap weld, which is arranged between the two anchoring elements 20 fixed respectively to one and the other of the two panels. adjacent primaries. Such an embodiment makes it possible to use corrugated metal sheets having limited dimensions and whose corrugations 17, 18 are centered with respect to the two central axes of the corrugated metal sheets.

There illustrates an overlap zone between two adjacent corrugated metal sheets 16 according to an alternative embodiment. In this variant embodiment, the two edge portions which are arranged to overlap one above the other are each welded to one of the anchoring elements 20 by means of a plug weld 22 or by transparency, as in the variant of the . However, in this embodiment, the edge portion which overlaps covers at least part of the plug weld 22 or by transparency of the other edge portion. To do this, the corrugated metal sheets 16 have a structure in which the corrugations are not arranged symmetrically with respect to the two median axes, as described and represented in relation to the .

Finally, in the embodiment of the , it is the edge portion which is intended to be covered by the other edge portion which is welded by means of plug welds 22 to the two anchoring elements 20 belonging respectively to one and the other of the two primary panels 7 adjacent. The other edge portion then covers the plug welds 22 in line with the anchoring elements 20 fixed to one and the other of the two adjacent primary panels. This makes it possible to further limit the length of plug welds 22 critical for the tightness of the primary waterproof membrane 8 and the tightness of which must, as such, be ensured.

There illustrates another embodiment. This embodiment differs from that described and illustrated in relation to FIGS. 2 to 4 only in that the undulations 17, 18 of the corrugated metal sheets 16 are arranged symmetrically with respect to the two central axes and in that the edges of the corrugated metal sheets 16 which overlap an adjacent edge of another corrugated metal sheet do not overlap any plug welds 22. This makes it possible to limit the dimensions of the corrugated metal sheets 16.

Figures 13 and 14 illustrate another embodiment. This embodiment differs from the embodiment described in relation to the by the structure of the anchoring elements 20 and by the type of welding carried out to fix the corrugated metal sheets 16 to the anchoring elements 20.

As illustrated on the , the anchoring elements 20 comprise a base 32 which is fixed to a primary insulating panel 7 and a sealing collar 33 which is welded in a sealed manner to the primary waterproof membrane 8 and is fixed to the base 32. For this do, the base 32 comprises a threaded bore 34 in which is screwed a threaded pin 35 passing through an orifice formed in the primary sealed membrane 8. The sealing flange 33 bears against the internal face of the membrane primary seal 8 and is welded to the primary seal membrane 8 all around the orifice so as to ensure sealing.

Figures 15 and 16 illustrate another embodiment of the invention. In this embodiment, the anchoring element 20 consists of an insert in the form of a disc 36 which is received in a countersink formed in the internal surface of a primary insulating panel 7 and which is fixed to said primary insulating panel 7 In the illustrated embodiment, the disc-shaped insert 36 is equipped with a threaded stud 37 which is received in a threaded hole made in a metal part 38 fixed to the primary insulating panel 7.

With reference to the , 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 tank 71 comprises a primary waterproof membrane intended to be in contact with the LNG contained in the tank, a secondary waterproof membrane 5 arranged between the primary waterproof membrane and the double hull 72 of the ship, and two thermally insulating barriers arranged respectively between the primary waterproof membrane and the secondary waterproof membrane and between the secondary waterproof membrane 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 also shows an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an installation on land 77. The loading and unloading station 75 is a fixed off-shore installation comprising a mobile 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 adjustable movable arm 74 adapts to all LNG tanker gauges. 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 shore installation 77. This 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 includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the claimed invention.

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

Claims (21)

Wall (1) of a sealed and thermally insulating tank for storing a liquefied gas, said wall (1) comprising at least one thermally insulating barrier (6) and a sealed membrane (8) which is anchored to said thermally insulating barrier (6) and is intended to be in contact with the liquefied gas, the thermally insulating barrier (6) comprising a first insulating panel (7) and a second insulating panel (7) arranged along a first edge of the first insulating panel , the first and second insulating panels (7) being respectively equipped with at least one first anchoring element (20) and at least one second anchoring element (20) on which the waterproof membrane (8) is welded ; the waterproof membrane (8) comprising undulations (17, 18) separated from each other by flat portions (19) and in which at least one of the flat portions (19) is arranged astride the first and the second insulating panels (7) and is welded on the one hand to the first anchoring element (20) and on the other hand to the second anchoring element (20). Wall (1) according to Claim 1, in which the waterproof membrane (8) comprises first undulations (17) extending parallel to a first direction and second undulations (18) extending parallel to a second direction, the first direction being perpendicular to the second direction. Wall (1) according to any one of Claims 1 to 2, in which the first and the second insulating panels (7) have a parallelepiped shape and each have two opposite edges parallel to the first direction and two opposite edges parallel to the second direction. Wall (1) according to any one of Claims 1 to 3, in which the first and second insulating panels (7) are respectively equipped with several first anchoring elements (20) and several second anchoring elements (20) and in which several of the planar portions (19) are arranged astride the first and the second insulating panels (7) and are each welded to one of the first anchoring elements (20) and to one of the second anchor (20). Wall (1) according to any one of Claims 1 to 4, in which the waterproof membrane (8) is welded to the at least one first anchoring element (20) and to the at least one second anchoring element. anchoring (20) by plug welding (22) or by transparency welding. Wall (1) according to any one of Claims 1 to 5, in which the at least one first anchoring element (20) and the at least one second anchoring element (20) each comprise a metal plate which is fixed in a countersink provided in one of the first and second insulating panels (7). Wall (1) according to Claim 6, in which the metal plate has the shape of a square, a rectangle or a disc. Wall according to any one of Claims 1 to 7, in which the first and second insulating panels (7) have relaxation slots facing the undulations (17, 18) of the waterproof membrane (8). Wall (1) according to any one of Claims 1 to 8, in which the at least one first anchoring element (20) and the at least one second anchoring element (20) are respectively placed on a portion external of the first insulating panel (7) and of the second insulating panel (8) delimited by at least one of the relaxation slots of the first or second insulating panel (7). Wall (1) according to any one of Claims 1 to 9, in which the impermeable membrane (8) comprises a plurality of corrugated metal sheets (16), each corrugated metal sheet (16) having edges which are each lap-welded to an edge of an adjacent corrugated metal sheet (16). Wall (1) according to Claim 10, in which the flat portion which is arranged astride the first and the second insulating panels (7) and is welded to the first and to the second anchoring elements (20) is made of a integrally in a single corrugated metal sheet (16). Wall according to Claim 11, in which the plane portion which is arranged astride the first and the second insulating panels (7) and is welded to the first and to the second anchoring elements (20) belongs to a first edge portion of one of the corrugated metal sheets (16); the first edge portion being covered by a second edge portion of an adjacent corrugated sheet metal (16), the first edge portion being welded to the first anchor (20) by means of a first plug weld (22) and being welded to the second anchor member (20) by means of a second plug weld (22), the second edge portion covering the second plug weld (22) and at least part of the first plug weld (22) and being sealingly lap welded to the first edge portion. Wall (1) according to Claim 10, in which the flat portion which is arranged astride the first and the second insulating panels (7) and is welded to the first and to the second anchoring elements (20) is produced by a first and a second edge portion of two adjacent corrugated metal sheets (16) which are lap welded to each other. Wall according to Claim 14, in which the first edge portion is intended to be covered by the second edge portion, the first edge portion being welded to the first anchoring member (20) by means of a weld, the second edge portion being welded to the second anchor member (20), covering at least a portion of the weld and being lap welded in a sealed manner to the first edge portion. Wall (1) according to Claim 10, in which the first and the second insulating panels (7) each have thermal protection elements (23) opposite the edges of the corrugated metal sheets (16). Wall (1) according to Claim 15, in which the thermal protection elements (23) are formed of an aluminum plate or of a composite film comprising at least one aluminum sheet associated with at least one mat of fibers of glass. Wall (1) according to any one of Claims 1 to 16, in which the thermally insulating barrier (6) comprises a third insulating panel (7) arranged along a second edge of the first insulating panel (7), a fourth insulation panel (7) disposed along a third edge of the first insulation panel (7) and a fifth insulation panel (7) disposed along a fourth edge of the first insulation panel (7) and wherein the third, fourth and fifth insulating panels (7) are respectively equipped with third, fourth and fifth anchoring elements (20), the waterproof membrane (8) comprising flat portions (19) arranged astride between the first and the third insulating panels (7) which are each welded on the one hand to one of the first anchoring elements (20) and on the other hand to one of the third anchoring elements (20), planar portions (19) arranged straddling the first and fourth insulating panels (7) which are each welded on the one hand to one of the first anchoring elements (20) and on the other hand to one of the fourth anchoring elements (20) and flat portions (19) arranged astride between the first and the fifth insulating panels (7) which are each welded on the one hand to one of the first anchoring elements (20) and on the other hand to one of the fifth anchoring elements (20). Sealed and thermally insulating tank comprising a wall (1) according to any one of claims 1 to 17. Vessel (70) for the transport of a fluid, the vessel comprising a hull (72) and a tank (71) according to claim 18 disposed in the hull. Transfer system for a fluid, the system comprising a ship (70) according to claim 19, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) installed in the hull of the ship to a floating or onshore storage facility (77) and a pump for driving fluid through the insulated pipelines from or to the floating or onshore storage facility to or from the vessel's tank. Method of loading or unloading a ship (70) according to claim 19, in which a fluid is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or terrestrial storage installation (77) to or from the ship's tank (71).