FR3101390A1 - Sealed and thermally insulating tank - Google Patents

Abstract

The invention relates to a sealed and thermally insulating vessel for the storage of liquefied gas, wherein the vessel comprises a first vessel wall and a second vessel wall, each of the first vessel wall and the second vessel wall being supported. by a supporting structure and comprises, a secondary thermally insulating barrier (2), a secondary waterproofing membrane (3), a primary thermally insulating barrier (4), and a primary waterproofing membrane (5), in which the tank comprises at least two corner structures (1) located at the level of the corner zone being separated from each other by an inter-panel space (8), each corner structure (1) comprises a set secondary corner assembly (6), wherein each corner structure (1) has a plurality of primary corner assemblies (12) attached to the secondary corner assembly (6), and the vessel has one assembly primary junction angle (13) fixed astride the two seco angle sets ndaires (6) of the two corner structures (1) juxtaposed so as to be located above the inter-panel space, and in which the primary junction angle assembly (13) has a bending behavior different from the primary corner sets (12) of the corner structures (1). Figure for the abstract: Fig. 1

Description

Watertight and thermally insulated tank

The invention relates to the field of sealed and thermally insulating membrane tanks. In particular, the invention relates to the field of sealed and thermally insulating tanks for the storage and/or transport of liquefied gas at low temperature, such as tanks for the transport of Liquefied Petroleum Gas (also called LPG) having for example a temperature between -50°C and 0°C, or for the transport of Liquefied Natural Gas (LNG) at around -162°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

Document KR20040095782 discloses a corner structure comprising a secondary insulating block of a first vessel wall and a secondary insulating block of a second vessel wall which are intended to form the corner of a secondary thermally insulating barrier and which are attached to each other. The two secondary insulating blocks thus form a secondary corner assembly. A secondary waterproofing membrane covers these two secondary insulating blocks.

In order to form the primary thermally insulating barrier, sets of primary angles are fixed on the secondary sealing membrane and are formed of a primary insulating block fixed via an external face above the secondary insulating block of the first wall of tank and another primary insulating block also fixed via an external face above the secondary insulating block of the second wall of the tank. The two primary insulating blocks are fixed to each other using a metal angle fixed on their internal face, and thus form a set of primary angles.

Two sets of adjacent secondary corners of the same vessel wall are spaced from each other by an inter-panel space. A primary junction corner assembly is fixed astride the two secondary corner assemblies so as to be located in line with the inter-panel space. The primary junction corner sets and the primary corner sets are made in this document in the same way.

This document discloses that the primary insulating blocks are made either entirely of plywood or on the internal face side of a plywood plate and on the internal face side of a layer of insulating foam.

Summary

It has been observed by the applicant that the primary junction corner assembly is subjected to greater forces than the others. In particular, when the vessel is cold, the primary insulating blocks and the primary junction corner assemblies contract, which has the effect of subjecting the primary corner assembly to tensile forces.

The bending of the beam of the ship carrying the tank also has the effect of subjecting the primary junction angle assembly to greater bending/shearing forces than the other primary angle assemblies, which can lead to its damage.

One idea underlying the invention is to modify the structure of this primary junction angle assembly.

According to one embodiment, the invention provides a sealed and thermally insulating tank for the storage of liquefied gas, in which the tank comprises a first tank wall and a second tank wall meeting at an edge and extending respectively along a first plane and a second plane inclined with respect to each other so as to form at the level of the junction between the first vessel wall and the second vessel wall a corner zone, each of the first vessel wall and of the second vessel wall being supported by a supporting structure and comprising, in a direction of wall thickness of the supporting structure towards an internal space of the vessel, a secondary thermally insulating barrier supported by the supporting structure, a secondary sealing membrane supported by the secondary thermally insulating barrier, a primary thermally insulating barrier supported by the secondary sealing membrane, and a primary sealing membrane supported by the primary thermally insulating barrier and intended to be in contact with a liquefied gas,
in which the tank comprises at least two corner structures which are located at the level of the corner zone, juxtaposed to each other in a direction parallel to the edge and are separated from each other by an inter-panel space, each corner structure comprising a secondary corner assembly providing continuity of the secondary thermally insulating barrier and of the secondary sealing membrane in the corner zone between the first vessel wall and the second tank wall,
wherein each corner structure has a plurality of main primary corner sets attached to the secondary corner set, and the vessel has a junction primary corner set straddling the two corner sets secondaries of the two corner structures juxtaposed so as to be located above the inter-panel space, the main primary corner sets of the corner structures and the primary junction corner set ensuring the continuity of the primary thermally insulating barrier and the primary sealing membrane in the corner zone between the first vessel wall and the second vessel wall,
and wherein the junction primary corner assembly has a different stiffness from the main primary corner assemblies of the corner structures.

Thanks to these characteristics, the different design of the primary junction angle assembly makes it possible to specifically adapt this element to the stresses it undergoes in order to prevent it from being damaged prematurely.

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

According to one embodiment, the primary junction angle assembly has a different tensile and/or bending stiffness from the main primary angle assemblies of the angle structures

According to one embodiment, the first tank wall and the second tank wall are flat.

According to one embodiment, the primary junction angle assembly has a rigidity, in particular a tensile rigidity, greater than the main primary angle assemblies of the angle structures.

According to one embodiment, the junction primary angle assembly has a higher average modulus of elasticity than the main primary angle assemblies of the angle structures.

According to one embodiment, the junction primary angle assembly has greater flexibility than the main primary angle assemblies of the angle structures.

According to one embodiment, the joining primary corner assembly is spaced from an adjacent primary primary corner assembly using an insulating foam shim.

According to one embodiment, the secondary corner assembly comprises a secondary insulating block extending in the first plane and a secondary insulating block extending in the second plane.

According to one embodiment, the secondary sealing membrane is attached to an upper part of each secondary insulating block of the secondary corner assembly.

According to one embodiment, the main primary corner assembly comprises a primary insulating block located in the same plane as the first vessel wall and a primary insulating block located in the same plane as the second vessel wall.

According to one embodiment, the primary junction corner assembly comprises a primary insulating junction block extending in the first plane and a primary insulating junction block extending in the second plane.

Thus, the primary insulating junction block of the first vessel wall is fixed astride above the two secondary insulating blocks of the juxtaposed corner structures so as to be located directly above the inter-panel space.

According to one embodiment, the primary insulating junction block comprises an upper part and a reinforced lower part located below the upper part, the reinforced lower part being fixed to the secondary sealing membrane, and the reinforced lower part having a modulus of elasticity or stiffness higher than the upper part.

Thanks to these characteristics, the reinforced lower part thus improves the overall resistance of the primary insulating junction block, enabling it to withstand greater or longer stresses during fatigue work.

According to one embodiment, the upper part is made of plywood.

According to one embodiment, the lower part comprises a layer of composite material, a layer of densified wood or the combination of the two.

According to one embodiment, the lower part comprises a metal plate.

For example, the densified wood can be wood having a density greater than or equal to 900 kg/m ³ , preferably between 1100 and 1300 kg/m ³ , for example of the order of 1200 kg/m ³ .

The composite material may include a layer of aluminum between two layers of fiberglass and resin, a laminated composite material called a rigid secondary barrier ("Rigid Secondary Barrier", RSB).

According to one embodiment, the reinforced lower part comprises a first layer made of densified wood and a second layer of laminated composite material.

According to one embodiment, the average modulus of elasticity of the reinforced lower part is greater than or equal to 1.5 times the modulus of elasticity of the upper part.

According to one embodiment, the ratio between the dimension of the lower part in the direction of thickness and the dimension of the upper part in the direction of thickness is less than or equal to 0.9, preferably between 0.005 and 0 ,5.

According to one embodiment, when the lower part comprises a layer made of densified wood, the ratio between the dimension of the layer made of densified wood and the upper part in the thickness direction is between 0.1 and 0.5 .

According to one embodiment, when the lower part comprises a layer of laminated composite material, the ratio between the layer of laminated composite material and the upper part in the thickness direction is between 0.005 and 0.1.

According to one embodiment, the primary insulating junction block comprises at least one metal or composite insert located above or plumb with the inter-panel space in the thickness direction, the metal or composite insert being configured to enhance the stiffness or flexibility of the primary junction insulator block.

According to one embodiment, the metal or composite insert thus improves the overall tensile, flexural and/or shear stiffness of the primary insulating junction block, enabling it to withstand greater or longer stresses. during fatigued work.

According to one embodiment, the metal or composite insert has a modulus of elasticity greater than that of the rest of the primary insulating junction block.

According to one embodiment, the metal or composite insert exerts a compressive prestress.

According to one embodiment, the metal or composite insert comprises a curved blade in the direction of thickness.

According to one embodiment, the primary insulating junction block comprises an upper part and a lower part located below the upper part, a lower surface of the lower part being fixed to the secondary sealing membrane,
and wherein the bottom portion includes at least one relaxation slot formed at the bottom surface of the bottom portion and extending in the thickness direction and in a direction perpendicular to the ridge direction, the relaxation slot relaxation being configured to decrease the rigidity of the primary insulating junction block.

Thanks to these characteristics, the relaxation slot makes it possible to increase the flexibility of the primary insulating junction block, allowing it to withstand greater or longer stresses during fatigue work.

According to one embodiment, the relaxation slot is located above or plumb with the inter-panel space in the direction of wall thickness.

According to one embodiment, the lower part comprises at least one pair of grooves located on either side of the relaxation slot in the direction of the edge, the grooves having a dimension in the direction of thickness smaller than that of the relaxation slot.

According to one embodiment, the relaxation slot and/or the grooves extend only in the lower part of the primary insulating junction blocks.

According to one embodiment, the primary insulating junction block is glued to the secondary sealing membrane above or plumb in the thickness direction of one of the juxtaposed secondary corner sets and above or plumb in the thickness direction of the other of the two sets of juxtaposed secondary corners, a free space being located between the primary insulating junction block and the secondary waterproofing membrane above or at the plumb in the thickness direction of the inter-panel space, so that there is no glue between the secondary waterproofing membrane and the primary insulating junction block in the thickness direction above of the inter-panel space.

Thanks to these characteristics, the absence of bonding of the primary insulating junction block plumb with the inter-panel space makes it possible to avoid propagation of a crack from the adhesive towards the primary insulating junction block in order to withstand stresses. more important or longer during work in fatigue.

According to one embodiment, the lower part is a reinforced lower part, the reinforced lower part having a greater rigidity than the upper part in order to resist the relative movement of the first secondary insulating block and of the second secondary insulating block.

According to one embodiment, the primary insulating junction blocks of the first tank wall and of the second tank wall each comprise an external face fixed to the secondary sealing membrane and an internal face, and the tank comprises a metal angle comprising a first part of angle iron fixed to the external face of the primary insulating block of junction of the first vessel wall and a second part of angle iron connected to the first part of angle iron and fixed to the external face of the primary insulating block of junction of the second tank wall.

According to one embodiment, the primary insulating junction blocks of the first vessel wall and of the second vessel wall comprise fixing orifices opening onto the external face of said primary insulating junction blocks, and the first angle part and the second part of angle iron comprise, on the surface facing said primary insulating junction blocks, fixing devices protruding, the fixing devices being configured to be fixed inside the fixing holes.

According to one embodiment, the fixing orifices emerge on either side of the primary insulating junction blocks.

According to one embodiment, the fixing holes extend only in the upper part of the primary insulating junction blocks.

Such a tank can be part of an onshore storage facility, for example to store LNG or be installed in a floating, coastal or deep water structure, in particular an LNG carrier, a floating storage and regasification unit (FSRU) , a floating production and remote storage unit (FPSO) and others. Such a tank can also serve as a fuel tank in any type of ship.

According to one embodiment, a vessel for the transport of a cold liquid product comprises a double hull and an aforementioned tank arranged in the double hull.

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

According to one embodiment, the invention also provides a method for loading or unloading such a ship, in which a cold liquid product is conveyed through insulated pipes from or to a floating or terrestrial storage installation to or from the ship'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.

FIG. 1 represents a partially exploded perspective view of a corner structure of a sealed and thermally insulating tank at the level of a junction between two secondary insulating blocks.

Figure 2 is an exploded schematic view of a primary insulating junction block.

Figure 3 shows a sectional view of Figure 2 along the line III-III according to a first embodiment.

Figure 4 shows a sectional view of Figure 2 along the line III-III according to a second embodiment.

Figure 5 shows a sectional view of Figure 2 along the line III-III according to a third embodiment.

Figure 6 shows a sectional view of Figure 2 along the line III-III according to a fourth embodiment.

Figure 7 shows a sectional view of Figure 2 along the line III-III according to a first embodiment.

FIG. 8 represents a schematic view of a primary insulating junction block positioned above two secondary insulating blocks according to one embodiment.

Figure 9 is a cutaway schematic representation of an LNG carrier comprising a tank and a loading/unloading terminal for this tank

By convention, we will call "on", "above" a position located closer to the inside of the tank and "under" or "below" a position located closer to the supporting structure, whatever the orientation of the vessel wall relative to the earth's gravity field. Similarly, "upper" or "internal" means an element located closer to the inside of the tank and "lower" or "external" means an element located closer to the supporting structure.

A corner structure 1 of a sealed and thermally insulating tank will be described below.

A sealed and thermally insulating tank comprises a plurality of walls each formed of at least one thermally insulating barrier and of at least one sealing membrane. In a corner of a sealed and thermally insulating tank at the junction between a first wall of the tank and a second wall of the tank, a corner structure 1 is placed in order to ensure the continuity of the thermally insulating barrier and of the membrane sealing of the two walls. In the embodiment that will be described, the vessel walls comprise a secondary thermally insulating barrier 2, a secondary sealing membrane 3 supported by the secondary thermally insulating barrier 2, a primary thermally insulating barrier 4 fixed to the membrane secondary sealing membrane 3 and a primary sealing membrane supported by the primary thermally insulating barrier 4.

Thus, the corner structure 1 comprises at least elements forming part of the secondary thermally insulating barrier 2 of the tank, at least elements forming part of the secondary sealing membrane 3 of the tank, at least elements forming part of the primary thermally insulating barrier 4 of the tank and at least elements forming part of the primary sealing membrane 5 of the tank. Consequently, the corner structure makes it possible to ensure the continuity of the various thermally insulating barriers and sealing membranes at the junction between a first vessel wall and a second vessel wall inclined with respect to the first vessel wall. a determined angle, for example an angle of 90° or an angle of 135°.

Figure 1 shows a corner of the tank where two corner structures 1 are juxtaposed in the direction of the edge 100 and spaced from each other by an inter-panel space 8.

As can be seen in Figure 1, each corner structure 1 comprises a secondary corner assembly 6 forming the extension of the secondary thermally insulating barrier 2 and of the secondary sealing membrane in the corner of the tank as well a plurality of main primary corner sets 12 juxtaposed to each other in the direction of the edge 100. The tank also comprises a primary junction corner set 13 fixed astride the two corner sets secondary 6 of two corner structures 1 juxtaposed so as to be located above the inter-panel space 8, as can be seen in particular in FIG. 8. The sets of primary corners 12 of the corner structures 1 and 1 The primary junction corner assembly 13 forms the extension of the primary thermally insulating barrier 4 and of the primary sealing membrane 5 in the corner zone between the first vessel wall and the second vessel wall.

The main primary corner sets 12 and the junction primary corner set 13 are aligned and spaced from each other in the direction of the ridge 100 on the secondary corner sets 6. The spaces between these sets of The main primary 12 and primary junction 13 corners are filled using insulating foam wedges 16.

The inter-panel space is filled using one or more joining wedges 9 of insulating material so as to maintain continuity of the secondary thermally insulating barrier 2 between two corner structures 1.

Each secondary corner assembly 6 thus comprises a secondary insulating block 7 in the plane P1 of the first vessel wall and a secondary insulating block 7 in the plane P2 of the second vessel wall arranged one to the other so to form the angle of the tank. In order to assemble the secondary insulating block 7 of the first wall with the secondary insulating block 7 of the second wall, each of the secondary insulating blocks 7 can comprise a beveled side edge so that the two secondary insulating blocks 7 are joined together. the other at their beveled lateral edge in order to form the angle corresponds to the angle of the angle structure 1. Alternatively, the secondary insulating blocks 7 can be assembled together via straight side edges by simply being tilted to each other at the desired angle. In this case, the space remaining at the level of the edge between these two secondary insulating blocks 7 is filled with insulation of a form complementary to said remaining space.

The secondary insulating blocks 7 comprise a lower plate and/or an upper plate, and optionally an intermediate plate, for example made of plywood. The secondary insulating blocks 7 also comprise one or more layers of insulating foam sandwiched between the lower plate, the upper plate and the optional intermediate plate and glued to them. The insulating foam may in particular be a polyurethane-based polymer foam, optionally reinforced with fibers.

The secondary corner assemblies 6 also comprise a rigid waterproof sheet 10 bonded to the upper plate of the secondary insulating blocks 7. The rigid waterproof sheet 10 is made of the same material as the secondary thermally insulating barrier 2 of the vessel walls so that the rigid sealed sheets 10 of a secondary corner assembly 6 form a continuity, at the level of the corner structure 1, of the secondary thermally insulating barrier 2.

In order to connect the rigid waterproof sheet 10 glued to one of the secondary insulating blocks 7 of the secondary corner assembly 6 and the rigid waterproof sheet 10 glued to the other of the secondary insulating blocks 7 of the secondary corner 6, a flexible waterproof sheet 11 is glued astride each of the rigid waterproof sheets 10 as shown in Figure 1.

The rigid waterproof sheets 10 of the two secondary insulating blocks 7 of the corner structure 1 and the flexible waterproof sheet 11 constitute the elements of the corner structure 1 forming a portion of the secondary waterproofing membrane 2 of the tank. The rigid waterproof sheet 10 is made of a laminated composite material comprising a layer of aluminum between two layers of fiberglass and resin, called a rigid secondary membrane (“Rigid Secondary Barrier”, RSB). The flexible waterproof sheet 11 is made of a laminated composite material comprising a layer of aluminum between two layers of glass fibers, called a flexible secondary membrane ("Flexible Secondary Barrier", FSB). At the junction between the two corner structures 1 in order to connect the two secondary corner sets 6 in a sealed manner, one or more flexible waterproof sheets 11 are glued astride the two secondary corner sets 6 so as to cover inter-panel space 8.

The primary junction angle assembly 13 has a different structure compared to the main primary angle assemblies 12 of the angle structures 1. Indeed, in order to avoid damage to the primary junction angle assembly 13 which undergoes more stress than the main primary corner assemblies 12, structural and/or material modifications are made to the primary junction corner assembly 13.

Figure 2 shows a primary junction angle assembly 13 in exploded view. The primary junction corner assembly 13 comprises a primary junction insulating block 15 located in the same plane P1 as the first vessel wall and a primary junction insulating block 15 located in the same plane P2 as the second vessel wall .

The primary insulating junction blocks 15 of the first vessel wall and of the second vessel wall each comprise an external face fixed to the secondary sealing membrane 3 and an internal face. The tank comprises a metal angle iron 18 comprising a first angle iron part 19 fixed to the external face of the primary insulating junction block 15 of the first wall of the tank and a second angle iron part 20 connected to the first angle iron part 19 and fixed on the outer face of the primary insulating junction block 15 of the second vessel wall.

The primary insulating junction blocks 15 of the first vessel wall and of the second vessel wall comprise fixing orifices 22 opening onto the outer face of said primary insulating junction blocks 15. The first part of angle iron 19 and the second part of bracket 20 comprise on the surface facing said primary insulating junction blocks 15 fixing devices 21 protruding. The fixing devices 21 are configured to be fixed inside the fixing holes 22. In the case of a parallelepipedal insulating block, the primary junction corner assembly 13 also comprises a corner wedge 17 made of insulating material located between the two primary insulating junction blocks 15 and against the flexible waterproof sheet 11. The corner wedge 17 makes it possible to achieve the continuity of the insulation where the orientation of the insulation is modified.

The main primary corner assemblies 12 also include a primary insulating block 14 located in the same plane P1 as the first vessel wall and a primary insulating block 14 located in the same plane P2 as the second vessel wall, a metal angle 18 fixing the two primary insulating blocks 14 to each other, and an angle wedge 17. The primary insulating blocks 14 are made entirely of plywood.

The specifics of the primary insulating junction blocks 15 will be described below. Figures 3 to 8 show different embodiments of the primary insulating junction blocks 15.

In the embodiments of FIGS. 3 to 6, unlike the primary insulating blocks 14, the primary insulating junction blocks 15 are not made entirely of plywood.

In the first embodiment illustrated in FIG. 3, the primary insulating junction block 15 comprises an upper part 23 and a reinforced lower part 24 located below the upper part 23 and glued to the latter. The reinforced lower part 24 is glued to the secondary waterproofing membrane 3. The upper part 23 is made of plywood and has for example a density of between 600 and 800 kg/m³, for example of the order of 700 kg/m³. The reinforced lower part 24 is made of densified wood which has a density greater than or equal to 900 kg/m³, preferably between 1100 and 1300 kg/m³, for example of the order of 1200 kg/m³and a higher modulus of elasticity than plywood. The fixing orifices 22 emerge on either side of the primary insulating junction block 15 from the external face to the internal face and thus pass through the upper part 23 and the reinforced lower part 24. The orifices 22 emerging on both sides allow to fix the metal bracket 18 even after the upper part 23 and the lower part have been assembled together.

FIG. 4 illustrates a second embodiment of a primary insulating junction block 15. This embodiment differs from the first embodiment only by the design of the fixing holes 22. Indeed, the fixing holes 22 extend only in the upper part 23 of the primary insulating junction block 15 and are therefore blind holes after assembly of the upper part 23 to the lower part 24.

FIG. 5 represents a third embodiment of a primary insulating junction block 15. This embodiment differs from the second embodiment by the materials used in the reinforced lower part 24. In this embodiment, the reinforced lower part 24 is composed of a first layer 25 and a second layer 26 glued to the first layer 25. The first layer 25 is made of densified wood and the second layer 26 is made of RSB laminated composite material.

FIG. 6 represents a fourth embodiment of a primary insulating junction block 15. This embodiment differs from the previous embodiments because it does not comprise an upper and lower part. However, the primary insulating junction block 15 comprises inside an insert 27 made of metallic material or composite material. The insert 27 comprises a curved blade in the direction of thickness. In the embodiment shown, the concavity of the curved blade is turned towards the internal face of the primary insulating junction block 15. However, in another embodiment, the concavity of the curved blade is turned in a direction opposite to the internal face of the primary insulating junction block 15.

According to one embodiment, the insert 27 is prestressed in compression. According to another embodiment, the insert 27 exerts a tensile prestress.

FIG. 7 represents a fifth embodiment of a primary insulating junction block 15. In this embodiment, the primary insulating junction block 15 comprises an upper part 23 and a lower part 24 located below the upper part 23. The bottom portion 24 includes a main relaxation slot 28 formed at the bottom surface of the bottom portion 24 and extending in the thickness direction and in a direction perpendicular to the direction of the ridge 100. relaxation slot 28 is located plumb with the inter-panel space in the direction of wall thickness. The lower portion 24 includes a pair of slots of grooves 29 located on either side of the relaxation slot 28 in the direction of the ridge 100. The grooves 29 have a dimension in the direction of thickness less than that of the relaxation slot 28 and make it possible to collect the excess glue likely to migrate into the zone of the lower part 24 which is opposite the inter-panel space 8.

According to another embodiment not shown, the relaxation slot 28 is not made by machining the lower part 24. In this embodiment, the lower part 24 comprises two blocks which are fixed to the upper part 23 and are spaced from each other so as to provide between them a relaxation slot 28.

FIG. 8 represents a sixth embodiment of a primary insulating junction block 15. In this embodiment, the primary insulating junction block 15 is glued to the secondary sealing membrane 3 plumb in the direction d wall thickness of one of the two juxtaposed secondary insulating blocks 7 and above or plumb in the thickness direction of the other of the two juxtaposed secondary insulating blocks of the same vessel wall. A free space is located between the primary insulating junction block 15 and the secondary sealing membrane 3 plumb in the wall thickness direction of the inter-panel space, so that there is no no glue between the secondary sealing membrane 3 and the primary insulating junction block 15 in the direction of the wall thickness plumb with the inter-panel space 8.

These structural specificities or materials of the primary insulating junction blocks 15 of the embodiments described above can of course be combined with each other. Indeed, for example, the primary insulating junction block 15 of FIG. 5 can also be provided with relaxation slots 28, 29, and/or an insert 27, and/or opening orifices 22, and/or of discontinuous bonding.

In other embodiments, it is also possible that one or more of the primary primary corner assemblies 12 are identical to the primary junction angle assembly 13 so long as the primary junction angle assembly 13 shows one of the structures described above.

Referring to Figure 9, 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 leaktight barrier intended to be in contact with the LNG contained in the tank, a secondary leaktight barrier arranged between the primary leaktight 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.

FIG. 9 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and an installation on land 77. The loading and unloading station 75 is a fixed off-shore installation comprising an 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 be connected to the loading/unloading pipes 73. The orientable mobile arm 74 adapts to all sizes of LNG carriers . A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the 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 invention.

The use of the verb "to comprise", "to understand" or "to include" and of 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 reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims (18)

Sealed and thermally insulating tank for the storage of liquefied gas, in which the tank comprises a first tank wall and a second tank wall meeting at the level of an edge (100) and extending respectively along a first plane (P1 ) and a second plane (P2) inclined with respect to each other so as to form at the junction between the first vessel wall and the second vessel wall a corner zone, each of the first wall of the vessel and of the second vessel wall being supported by a supporting structure and comprising, in a direction of thickness of the wall of the supporting structure towards an internal space of the vessel, a secondary thermally insulating barrier (2) supported by the supporting structure , a secondary sealing membrane (3) supported by the secondary thermally insulating barrier (2), a primary thermally insulating barrier (4) supported by the secondary sealing membrane (3), and a primary sealing membrane (5 ) supported by the primary thermally insulating barrier (4) and intended to be in contact with a liquefied gas,
in which the tank comprises at least two corner structures (1) located at the level of the corner zone juxtaposed to each other in a direction parallel to the edge and being separated from each other by an inter-panel space (8), each corner structure (1) comprising a secondary corner assembly (6) ensuring continuity of the secondary thermally insulating barrier (2) and of the secondary sealing membrane (3 ) in the corner area between the first vessel wall and the second vessel wall,
wherein each corner structure (1) has a plurality of main primary corner sets (12) attached to the secondary corner set (6), and the vessel has a junction primary corner set ( 13) fixed astride the two secondary corner sets (6) of the two corner structures (1) juxtaposed so as to be located above the inter-panel space (8), the corner sets main primaries (12) of the corner structures (1) and the primary junction corner assembly (13) ensuring the continuity of the primary thermally insulating barrier (4) and of the primary sealing membrane (5) in the corner zone between the first vessel wall and the second vessel wall,
and wherein the junction primary angle assembly (13) has a different stiffness from the main primary angle assemblies (12) of the angle structures (1). A tank according to claim 1, wherein the primary junction corner assembly (13) comprises a primary junction insulating block (15) extending in the first plane (P1) and a primary junction insulating block (15) extending into the second plane (P2). Tank according to claim 2, in which the primary insulating junction block (15) comprises an upper part (23) and a lower part (24) reinforced located below the upper part (23), the lower part (24) reinforced being fixed to the secondary waterproofing membrane (3), and the reinforced lower part (24) having a greater rigidity than the upper part (23). Tank according to Claim 3, in which the upper part (23) is made of plywood. Tank according to Claim 3 or Claim 4, in which the lower part (24) comprises a layer of composite material, a layer of densified wood or a combination of the two. Tank according to one of Claims 3 to 5, in which the average modulus of elasticity of the reinforced lower part (24) is greater than or equal to 1.5 times the modulus of elasticity of the upper part (23). Tank according to one of Claims 3 to 6, in which the ratio between the dimension of the lower part (24) in the direction of thickness and the dimension of the upper part (23) in the direction of thickness is less than or equal to 0.9, preferably between 0.005 and 0.5. Tank according to one of Claims 2 to 7, in which the primary insulating junction block (15) comprises at least one metallic or composite insert (27) situated above the inter-panel space (8) in the direction in thickness, the metallic or composite insert being configured to reinforce the rigidity in the thickness direction of the primary insulator junction block (15). Tank according to one of Claims 2 to 8, in which the primary insulating junction block (15) comprises an upper part (23) and a lower part (24) located below the upper part (23), a surface lower part of the lower part (24) being fixed to the secondary sealing membrane (3),
and wherein the bottom portion (24) includes at least one relaxation slot (28, 29) formed at the bottom surface of the bottom portion (24) and extending in the wall thickness direction and in a direction perpendicular to the direction of the ridge (100), the relaxation slot (28, 29) being configured to decrease the rigidity of the primary insulating junction block (15). A tank according to claim 9, wherein the relief slot (28, 29) is located above the inter-panel space (8) in the wall thickness direction. Tank according to one of Claims 2 to 10, in which the primary insulating junction block (15) is glued to the secondary sealing membrane (3) above in the thickness direction of one of the sets of juxtaposed secondary corners (6) and above in the thickness direction of the other of the juxtaposed secondary corner assemblies (6), a free space being located between the primary insulating junction block (15) and the membrane secondary sealing membrane (3) above in the thickness direction of the inter-panel space (8), so that there is no glue between the secondary sealing membrane (3) and the primary junction insulating block (15) in the thickness direction above the inter-panel space (8). Vessel according to one of Claims 2 to 11, in which the primary insulating junction blocks (15) of the first vessel wall and of the second vessel wall each comprise an external face fixed to the secondary sealing membrane (3 ) and an internal face, and the tank comprises a metal angle iron (18) comprising a first angle iron part (19) fixed to the external face of the primary insulating junction block (15) of the first tank wall and a second part of angle iron (20) connected to the first angle iron part (19) and fixed to the outer face of the primary insulating junction block (15) of the second vessel wall. Vessel according to Claim 12, in which the primary insulating junction blocks (15) of the first vessel wall and of the second vessel wall comprise fixing orifices (22) opening onto the external face of the said primary insulating junction blocks ( 15), and the first angle part (19) and the second angle part (20) comprise on the surface facing said primary insulating junction blocks (15) fixing devices (21) protruding, the fixing devices (21) being configured to be fixed inside the fixing holes (22). Tank according to Claim 13, in which the fixing orifices (22) emerge on either side of the primary insulating junction blocks (15). Tank according to Claims 3 and 13 taken in combination, in which the fixing holes (22) extend only in the upper part (23) of the primary insulating junction blocks (15). Vessel (70) for transporting a cold liquid product, the vessel comprising a double hull (72) and a tank (71) according to one of Claims 1 to 15 arranged in the double hull. Transfer system for a cold liquid product, the system comprising a vessel (70) according to claim 16, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) installed in the hull of the vessel to a floating or onshore storage facility (77) and a pump for driving a flow of cold liquid product through the insulated pipes 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 16, in which a cold liquid product 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).