EP4048935A1

EP4048935A1 - Tank for storing natural gas in a liquid state aboard a vessel

Info

Publication number: EP4048935A1
Application number: EP20793001.7A
Authority: EP
Inventors: Alexandre Tocatlian; Edouard DUCLOY
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2019-10-25
Filing date: 2020-10-23
Publication date: 2022-08-31
Also published as: KR20220087469A; CN114599912B; FR3102532B1; FR3102532A1; WO2021078981A1; CN114599912A

Abstract

The present invention relates to a sealed and thermally insulating tank (26) intended for storing a fluid and capable of resting on a supporting structure (6) of a vessel, the sealed tank (26) comprising a plurality of tank walls including a first vessel wall (30) and at least one second vessel wall (32), the first vessel wall (30) extending mainly in a first plane and the second vessel wall (32) extending mainly in a second plane, the first plane and the second plane being perpendicular to each other, the first tank wall (30) and the second tank wall (32) being connected by an angular connecting piece (34), characterised in that the angular connecting piece (34) has a first portion (56) extending mainly in the first plane, a second portion (58) extending mainly in the second plane and at least one intermediate portion (60) extending mainly in a plane that intersects the first plane and the second plane.

Description

DESCRIPTION

Title: Natural gas tank in the liquid state of a ship

The present invention relates to the field of natural gas tanks in the liquid state in maritime transport.

Liquid natural gas is transported by sea in sealed and thermally insulating storage tanks on transport ships. Natural gas is kept in liquid form to increase the amount of natural gas transported per tank, the volume of one liter of natural gas in liquid form being much less than the volume of one liter of natural gas in gaseous form. These tanks maintain the liquid natural gas at very low temperature, and more precisely at a temperature below -163 ° C, temperature at which the natural gas is in liquid form at atmospheric pressure.

Such liquid natural gas tanks can also be used as a reservoir by some ships. In other words, ships load and store liquid natural gas in their tanks and then use the liquid natural gas as fuel.

Liquid natural gas tanks generally have a parallelepipedal shape, the walls of which are carried by the internal hull of the ship in which the tank or tanks are installed. More particularly, the hulls of ships on which the tanks are loaded include an outer hull in contact with the external environment of the ship, and an internal hull used as a supporting structure for the tanks. Stiffeners extend between the outer shell and the inner shell to support the inner shell, as well as the walls of the vessel (s).

Once loaded into a tank, liquid natural gas exerts pressure on the walls of the tank. The previously mentioned stiffeners make it possible to ensure that the walls withstand this pressure. The junction zones of the walls of the tank, or in other words the corners of the parallelepipedal shape of this tank, can very particularly be weakened by this pressure and it is necessary to ensure the tightness of the tank in these. junction areas of the walls, in order to to avoid contamination of the vessel wall by liquid natural gas, or even in certain cases a leak from the storage vessel leading to a loss of the stored liquid natural gas.

In this context, the present invention firstly relates to a sealed and thermally insulating tank capable of resting on a supporting structure of a ship, the sealed tank comprising a plurality of tank walls including a first tank wall and at the bottom. least a second vessel wall, the first vessel wall extending mainly in a first plane and the second vessel wall extending mainly in a second plane, the first plane and the second plane being perpendicular to each other the other, the first tank wall and the second tank wall being linked by an angular junction piece, characterized in that the angular junction piece has a first portion extending mainly in a plane parallel to the first plane, a second portion extending mainly in a plane parallel to the second plane and at least one intermediate portion extending mainly in a plane secant to the first plane and the second plane, the first 1st portion of the angular junction piece having a thickness equivalent to that of the first tank wall and extending in the extension of this first tank wall and the second portion of the angular junction piece having a thickness equivalent to that of the second vessel wall and extending in the extension of this second vessel wall.

It will be understood that the vessel is intended to receive liquid natural gas, the natural gas having to be at a maximum temperature of -160 ° C. in order to be kept in its liquid form at atmospheric pressure. Thus, the tank comprises a succession of layers ensuring firstly the maintenance of the liquid natural gas at a temperature of at most -160 ° C and secondly maximum sealing to reduce the risk of leakage of the liquid natural gas. This tank can in particular be used for storing liquid natural gas during navigation or while awaiting its unloading at the quay, for example, or even be used to supply the machinery of the ship on which the tank is on board. Such a temperature of liquid natural gas can increase if it is kept in the tank at a pressure greater than the pressure. atmospheric. By way of example, the tank can be operated at a pressure of 1 bar gauge and in such a case, the natural gas will be maintained in the liquid state at a maximum temperature of -152 ° C.

The tank is supported by the internal hull of the vessel, which forms the supporting structure, because this tank with a membrane is not a self-supporting structure. The internal shell is provided to house the tank and withstand the pressure exerted by the liquid natural gas stored in the tank on the walls of the tank.

The tank has at least two walls, the two walls being perpendicular to each other. The stored liquid natural gas exerts a pressure on each of these walls and the structure of the tank with the junction part according to the invention makes it possible to manage the pressure exerted at the level of the junction zone between the two walls, in order to limit the risk of liquid natural gas leakage at this junction zone.

The junction piece is particular in that it has three parts among which two parts here called the first portion and second portion, are respectively arranged in a plane parallel to the extension plane of one of the side walls of the tank, and a third part, here called intermediate portion, is inclined relative to each of the other parts. This third part forms an intermediate part, arranged between the other two parts, which is configured to distribute the pressures exerted by the liquid natural gas in the direction of each of the side walls of the vessel. As has been specified, the angular junction piece and / or the angular junction element have a similar or substantially similar thickness, except for manufacturing clearances, to the thickness of the first tank wall and / or to the thickness of the tank. 'thickness of the second tank wall so that the angular junction piece ensures structural continuity of the tank at a corner of the tank, making a structural link between two perpendicular side walls mainly forming the tank but which does not show no continuity with respect to each other.

According to another optional characteristic of the invention, the sealed tank comprises at least one third tank wall extending mainly in a third plane perpendicular to the first plane, to the second plane and to the secant plane, and having a junction zone with the first tank wall and the second tank wall, in which the junction zone comprises an angular junction element, the angular junction element comprising a first part and a second part, the first part having a first section extending mainly in the first plane, a second section extending mainly in the second plane and an intermediate section extending mainly in the secant plane, the second part having a return wall perpendicular to the first part and extending mainly in the third plane.

The third tank wall extends in a plane perpendicular to the extension plane of the first tank wall, to the extension plane of the second tank wall as well as to the extension plane of the first portion, of the second portion and the intermediate portion of the junction piece.

The junction element thus ensures the connection between the third tank wall and the first tank wall, the second tank wall and the junction piece, thanks to a first part extending in the extension planes of the first vessel wall, the second vessel wall, as well as the angular junction piece, and thanks to a second part extending in the extension plane of the third vessel wall.

The angular junction element also ensures the distribution of the pressure exerted by the liquid natural gas on the internal face of the vessel at the level of the connection zone of the first vessel wall, of the second vessel wall and of the third. tank wall.

According to an optional characteristic of the invention, the angular junction piece and / or the angular junction element each have an internal face and an external face, the internal face forming an internal chamfer at the level of the intermediate portion or at the level of the intermediate section and the external face forming an external chamfer at the level of the intermediate portion or at the level of the intermediate section, the internal and external chamfer inclining at an angle of between 120 ° and 150 ° with respect to the foreground and to the second plan. It is understood that the third part, that is to say the intermediate portion, of the junction piece between the first tank wall and the second tank wall is advantageously inclined at an angle of 135 °, plus or minus 15 ° , with respect to each of the extension planes of the first part and of the second part of the junction piece, respectively called the first portion and the second portion, so that the distribution of the pressure exerted by the liquid natural gas is as well carried out on one or the other of the side walls linked by the junction piece.

Like the angular junction piece, the third part of the junction piece between the first tank wall and the second tank wall is inclined at 135 °, plus or minus 15 °, with respect to each of the extension planes of the first part and the second part of the connecting piece.

According to another optional characteristic of the invention, the dimension of the intermediate portion of the angular junction part measured between the first portion and the second portion of said part, and / or the dimension of the intermediate section of the junction element angular measured between the first section and the second section of said element, increases while going from the internal face towards the external face.

It follows that the internal surface, and more particularly the internal chamfer as it could be mentioned previously, is less wide than the external surface, and more particularly the external chamfer, the width being understood as the dimension perpendicular to the longitudinal direction along which mainly extends the junction piece.

According to another optional characteristic of the invention, the angular junction piece and / or the angular junction element successively comprise in the direction of the thickness from the outside to the inside of the sealed tank, a thermally insulating barrier secondary capable of being in contact with the supporting structure, a secondary waterproofing membrane carried by the secondary thermally insulating barrier, a primary thermally insulating barrier resting against the secondary waterproofing membrane and a primary waterproofing membrane carried by the thermally barrier primary insulator and intended to be in contact with the fluid contained in the sealed tank. The vessel walls as well as the junction parts of the liquid natural gas storage vessel are composed of at least one secondary space and one primary space, the secondary space of the vessel wall rests on the internal shell of the tank. ship through mastic rods. The secondary space is composed, successively from the outer face to the inner face of the tank, of a secondary thermal insulation barrier and a secondary waterproofing membrane. The primary space is for its part made up, successively from the outer face of the tank to the inner face of the tank, of a primary thermal insulation barrier and a primary waterproofing membrane.

According to another optional characteristic of the invention, the secondary space of a junction piece, composed of at least one secondary thermal insulation barrier and of a secondary waterproofing membrane, is arranged in the extension of the secondary space of the tank wall which it extends, these two secondary spaces being of the same constitution. Also, the primary space of a junction piece, composed of at least one primary thermal insulation barrier and a primary waterproofing membrane, is arranged in the extension of the primary space of the tank wall. that it extends, these two primary spaces being of the same constitution.

The thermal insulation barriers help maintain the temperature of the liquid natural gas stored in the storage tank by limiting heat exchange between the environment outside the storage tank and the inside of the storage tank. The waterproof membranes prevent any leakage of liquid natural gas.

According to another optional characteristic of the invention, the secondary thermally insulating barrier and the secondary sealing membrane of the angular junction part and / or of the angular junction element have, in a given direction, a greater dimension than the corresponding dimension, in the same direction, of the primary thermally insulating barrier and of the primary waterproofing membrane.

The first portion of the angular junction piece extends mainly in the first plane of the intermediate portion along a vertical direction. The dimension of the secondary space measured along the vertical direction is greater than the dimension of the primary space also measured along the vertical direction at the first portion. This applies similarly to the first section of the angular junction element.

The second portion of the angular junction piece extends mainly in the second plane of the intermediate portion along a transverse direction. The dimension of the secondary space measured along the transverse direction is greater than the dimension of the primary space also measured along the transverse direction at the second portion. This applies similarly to the second section of the angular joint member.

The first portion, the second portion and the intermediate portion of the angular junction piece extend along a longitudinal direction common to the three portions. The dimension of the secondary space measured along the longitudinal direction is greater than the dimension of the space measured also along the longitudinal direction at each of the portions of the angular junction piece. This applies similarly to each of the sections of the angular joint member.

At the ends of the junction pieces, the secondary space is uncovered leaving the secondary waterproofing membrane free. When mounting the tank, a primary space panel is then positioned so as to simultaneously overlap the first portion of the junction piece and the first tank wall, the panel thus making the junction element and this first wall integral. tank. The same assembly is used between the second portion of the junction part and the second tank wall as well as at the level of the first section, the second section and the return wall of the angular junction element.

The deflection wall extends in a plane perpendicular to the first plane, to the second plane and to the secant plane and parallel to the vertical and transverse directions. The dimension of the secondary space measured along the vertical direction is greater than the dimension of the primary space also measured along the vertical direction at the return wall. In addition, the dimension of the secondary space measured along the transverse direction is greater than the dimension of the primary space also measured along the transverse direction at the return wall.

According to another optional feature of the invention, a dimension of the first portion and / or of the second portion of the angular junction piece has a value equivalent to that of the dimension of the intermediate portion.

The subject of the invention is also a vessel comprising at least one sealed tank as described above.

According to an optional characteristic of the invention, the ship comprises an outer hull and a supporting structure, the supporting structure being intended to house the sealed tank, the supporting structure having a first bearing wall extending mainly along the foreground and a second bearing wall extending mainly along the second plane, the first bearing wall and the second bearing wall being substantially perpendicular, characterized in that a clearance zone is provided between the bearing walls of the supporting structure in the junction zone and the intermediate portion of the angular junction piece, and in that a reinforcing element is housed in said clearance zone.

This reinforcing element makes it possible to provide a bearing face for the angular junction piece which is substantially perpendicular to the direction of the pressure exerted by the liquid natural gas present in the vessel at the level of the junction zone of the vessel walls. .

According to another optional characteristic of the invention, the reinforcing element has a triangular shaped section, the reinforcing element having a vertex whose angle is equivalent to the right angle formed between the first bearing wall and the second bearing wall, the reinforcing element having a contact face with the intermediate portion which is opposite to this apex.

The contact face of this reinforcing element may have a planar shape and form a square such that during contact between the reinforcing element and the intermediate portion of the angular junction piece, the stresses are evenly distributed over the entire contact face forming the support face. Alternatively, this contact face could have a faceted profile, being formed of a plurality of flat surfaces inclined with respect to each other so as to tend towards a profile curved towards the inside of the reinforcement element. . Alternatively, and in particular to facilitate the production of the reinforcing element arranged at the junction of the bearing walls of the supporting structure, this contact face may have a curved profile with a generally concave shape of the reinforcing element. In this context of a curved face, reinforcements and / or leveling material could be placed in the space thus formed between the contact face and the intermediate portion of the angular junction part.

According to another optional characteristic of the invention, the outer shell has a plurality of stiffeners in contact with the supporting structure, the concentration of stiffeners being reduced near the angular junction piece and / or near the junction element angular. In other words, the distance between two neighboring stiffeners of a plurality of stiffeners arranged between the outer shell and the supporting structure varies depending on whether one is near or far from the angular junction piece, this distance being greater when we approach the angular junction piece.

These stiffeners make it possible to transmit the pressure exerted by the liquid natural gas present in the tank on the outer hull of the ship. The presence of the angular junction piece and / or the angular junction element makes it possible to better distribute the pressure exerted by the liquid natural gas in the direction of the vessel walls, thus reducing the need for stiffeners at these junction zones. . According to another optional characteristic of the invention, a dimension of the intermediate portion of the angular junction piece is determined as a function of the position of the stiffener closest to a corner of the internal bearing structure in which the piece of support is positioned. angular junction, so that with D60 the dimension of the intermediate portion, and d the distance between the first stiffener and the corner of the internal load-bearing structure.

The dimension mentioned of the intermediate portion corresponds to the length of the outer face of this intermediate portion between a first bonded edge forming a junction between the intermediate portion and the first portion and a second bonded edge forming a junction between the intermediate portion and the second portion.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows, on the one hand, and of several embodiments given by way of indication and not by way of limitation with reference to the appended schematic drawings on the other hand. share, on which:

[Fig. 1] is a side view of a transport vessel showing at least one tank of natural gas in a liquid state;

[Fig. 2] is a sectional view of the schematic representation of a tank comprising at least one angular junction piece arranged between the various side walls of the tank and of a shell comprising an outer shell, stiffeners and an internal supporting structure inside. of which the tank is housed;

[Fig. 3] is an interior view of a plurality of connecting pieces;

[Fig. 4] is a cross section of a tank, the internal supporting structure and the outer shell at the connection of two side walls of the tank;

[Fig. 5] is a view of the interior of the vessel of an angular junction element and a first transverse vessel wall;

[Fig. 6] is a view of the interior of the vessel of at least one angular junction piece and at least one angular junction member;

[Fig. 7] is a cross section of a particular embodiment of the tank, of the internal supporting structure, of the stiffeners and of the external shell, in a representation similar to that of FIG. 4;

[Fig. 8] illustrates a variant of the embodiment of FIG. 7. The characteristics, variants and the different embodiments of the invention can be associated with each other, in various combinations, insofar as they are not compatible or exclusive with respect to each other. It is in particular possible to imagine variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage and / or to differentiate the invention. compared to the state of the prior art.

In FIG. 1 is shown a transport vessel 200, for example an LNG carrier, which comprises four tanks 26 for the transport or storage of liquefied natural gas, one of these tanks being made visible here to facilitate understanding. The transport vessel 200 can be configured to only store and transport this liquefied natural gas, or to use it as fuel for the operation of the vessel. As is more particularly illustrated in FIG. 2, such a vessel has a hull 2 comprising at least one outer hull 4 and an internal supporting structure 6, between which extend a plurality of stiffeners 8, 10. The outer hull 4 is in contact with the external environment of the ship, generally a maritime and / or river environment. The internal supporting structure 6 extends away from this external shell. The dimension of the stiffeners determines the distance between the outer shell 4 and the internal supporting structure 6, each stiffener being integral with the outer shell 4, at a first end 12, and in contact with the internal supporting structure 6, at the level of a second end 14. It will be understood that stiffeners are advantageously present on the whole of the internal supporting structure 6.

The internal bearing structure 6 comprises a plurality of bearing walls, including a first bearing side wall 18 and at least one second bearing side wall 20 which extend in perpendicular planes. The first bearing side wall 18 comprises a first longitudinal side 21 and the second bearing side wall 20 comprises a second longitudinal side 23 at the level of which the second bearing side wall 20 is adjacent to the first bearing side wall 18.

In other words, the first bearing side wall 18 and the second bearing side wall 20 are thus perpendicular to each other at the level of a junction zone 24 between the first longitudinal side 21 of the first bearing side wall 18 and the second longitudinal side 23 of the second bearing side wall 20.

The internal supporting structure 6 houses at least one sealed and thermally insulating tank 26, said tank 26 being intended to receive liquid natural gas. The sealed and thermally insulating tank 26 has an internal face 27, which is in contact with the liquid natural gas when it is stored in the sealed and thermally insulating tank, and an external face 29, resting on the plurality of bearing walls, and in particular the first or second bearing side wall 18, 20, of the internal supporting structure 6. The sealed and thermally insulating tank 26 advantageously extends in the form of a rectangular parallelepiped. The sealed and thermally insulating vessel 26 thus has a plurality of vessel walls, including a first vessel side wall 30 and at least one second vessel side wall 32.

Each of the vessel side walls 30, 32 rests against a corresponding bearing side wall 18, 20. More particularly here, in the example illustrated, the outer face 29 of the first side wall of tank 30 rests on the first side wall of bearing 18 of the internal supporting structure 6 and the outer face of the second side wall of tank 32 rests on against the second bearing side wall 20 of the internal supporting structure 6. It follows from the foregoing that the second vessel side wall 32 and the first vessel side wall 30 extend in planes perpendicular to each other with respect to the other.

According to the invention, the first side vessel wall 30 and the second side vessel wall 32 are connected to each other by being jointly integral with at least an angular junction piece 34 according to the invention which extends at the level of the junction zone 24 previously mentioned.

As illustrated in particular in FIGS. 2, 4, 7 and 8, the angular junction piece 34 forms an extension of each of the side walls of the tank by having a similar thickness, or substantially similar, except for manufacturing clearances, to that of the first side wall of tank 30 and / or of the second side wall of tank 32. In other words, the angular junction piece makes it possible to generate structural continuity of the tank by making a link between two perpendicular side walls mainly forming the tank but which do not have any continuity with respect to each other.

The thickness of one or the other of the side walls of the vessel 30, 32 is here measured, along a direction perpendicular to the plane in which mainly extends the side wall of the vessel 30, 32 concerned, between the internal face 27 and the external face 29. Thus, in the example illustrated, the thickness of the first side wall of the tank 30 is measured along a direction parallel to the transverse axis B and the thickness of the second. vessel side wall 32 is measured along the vertical axis C.

More particularly, a first portion of the angular junction piece is arranged in the extension of the first side wall of tank 30, said first portion and said first side wall of tank having thickness values, respectively measured along axes mutually parallel, here parallel to the transverse axis B, similar or substantially similar to one another. Similarly, a second portion of the angular junction piece is arranged in the extension of the second side wall of tank 32, said second portion and said second side wall of tank having thickness values, respectively measured along parallel axes. between them, here parallel to the vertical axis C, similar or substantially similar to one another.

Advantageously, the angular junction piece 34 has a first thickness similar to the thickness of the first side wall of vessel 30 at least at the level of a contact zone between the angular junction piece 34 and the first side wall of vessel 30. , and a second thickness similar to the thickness of the second side wall of the tank 32 at least at an area contact between the angular junction part 34 and the second side wall of the tank 32.

The structure of this angular junction piece 34 will now be described in more detail, with reference to FIGS. 3 and 4 in particular. In accordance with the structure of the vessel walls 30, 32 that it participates in connecting, the angular junction piece 34 comprises, successively from the outer face to the inner face, a secondary thermal insulation barrier 36, a waterproofing membrane secondary 38, a primary thermal insulation barrier 40 and a primary waterproofing membrane 42. The secondary thermal insulation barrier 36 and the secondary waterproofing membrane 38 form a secondary space 37 and the primary thermal insulation barrier 40. and the primary waterproofing membrane 42 form a primary space 41.

It will be understood from the above, as will be detailed below, that on the one hand the primary space, formed of the primary thermal insulation barrier 40 and of the primary waterproofing membrane 42, of the part of angular junction extends both in the extension of an equivalent primary space of the first side wall of tank 30 and in the extension of an equivalent primary space of the second side wall of tank 32, and that other apart from the secondary space, formed of the secondary thermal insulation barrier 36 and of the secondary waterproofing membrane 38, the angular junction piece extends both in the extension of an equivalent secondary space of the first side wall of tank 30 and in the extension of an equivalent secondary space of the second side wall of tank 32.

The secondary thermal insulation barrier 36 comprises, successively from the external face of the tank towards the secondary waterproofing membrane 38, a first insulation wall 44 and a first layer of thermal insulation 46. The first insulation wall 44 comprises a board having substantially the shape of a rectangular parallelepiped. The board is advantageously made of plywood, for example wood plywood. The dimensions of the board are adapted to the size of the blocks of the secondary thermal insulation barrier 36. The first layer of thermal insulation 46 may be formed by a cellular plastic material, such as a polyurethane foam for example, allowing effective thermal insulation and well distributed between the insulation walls.

Furthermore, the angular junction piece 34 comprises a second insulating wall 51 arranged to cover the first layer of thermal insulation 46, between this first layer and the secondary waterproofing membrane 38. This second insulating wall 51 , also formed of a plank advantageously in plywood, for example a wood plywood, is specifically arranged in the angular junction piece, without it necessarily being provided in the composition of the tank walls. This second insulation wall 51 is in particular provided for better resistance to the pressure generated on the wall junctions by the natural gas present in the tank.

The secondary thermal insulation barrier 36, and more particularly the second insulation wall 51, is integral with the secondary waterproofing membrane 38, for example by gluing.

The secondary waterproofing membrane 38 includes a flexible secondary waterproofing membrane 48 and a rigid secondary waterproofing membrane 49.

More particularly, a rigid secondary waterproofing membrane 49 is specific to each portions 56, 58, 60 of the angular junction piece 34 and a flexible secondary waterproofing membrane 48 is common to all of the portions, by overlapping at least partial of each of the rigid secondary waterproofing membranes 49 which covers the secondary thermally insulating barrier 36 at the level of the flat surfaces. It will be understood that the secondary thermally insulating barrier of each portion of the angular junction piece 34 is covered by the rigid secondary waterproofing membrane 49, but that the intersections between each of the portions remain uncovered. The flexible secondary waterproofing membrane 48 is positioned overlapping the intersections between each of the portions 56, 58, 60 of the angular junction piece 34 and between each rigid secondary waterproofing membrane 49 covering said portions 56, 58, 60, decreasing the risk of contamination in these risk areas. The flexible secondary waterproofing membrane 48 is a triplex strip, composed of an aluminum sheet bonded between two braided glass mats, these components of the triplex strip not being shown in all of the figures. The flexible secondary waterproofing membrane 48 is on the one hand in contact and bonded to the rigid secondary waterproofing membrane 49 and, on the other hand, to the primary thermal insulation barrier 40.

The rigid secondary waterproofing membrane 49 consists of an aluminum foil bonded between two braided glass mats impregnated with a polymer resin.

The primary thermal insulation barrier 40 comprises a second thermal insulating layer 52 and a third insulation wall 54 and reference may be made to the above for the composition and function of each of these layers.

During the assembly of the sealed and thermally insulating tank 26, the angular junction piece 34 and the plurality of tank walls are mounted by means of the assembly panels, arranged one beside the other and each comprising the different elements. constituents of the angular junction part 34 and of the plurality of vessel walls. These assembly panels can be covered with the primary waterproofing membrane 42, which can be stainless steel with waves. It should be noted that, alternatively, the primary waterproofing membrane 42 is, for example, made of invar® sheet.

The side walls of the tank 30, 32 each extend along a main elongation plane, these elongation planes being perpendicular to each other and the angular junction piece 34 extends in three different planes, the angular junction piece 34 having at least three different portions extending respectively in one of these three different planes.

According to the first embodiment, the angular junction piece 34 comprises a first portion 56, a second portion 58 and at least one intermediate portion 60. The number of intermediate portions is not limiting, and it should be imagined according to l invention an angular junction piece 34 having for example four portions with two intermediate portions connecting to one another the first portion 56 and the second portion 58. As illustrated, the first portion 56 extends the intermediate portion 60 in a vertical direction, substantially parallel to a vertical axis C, and the second portion 58 extends the intermediate portion in a perpendicular transverse direction, substantially parallel to a transverse axis B.

The first portion 56 and the second portion 58 each have primary 41 and secondary 37 spaces which do not extend over the same dimension, in a given direction, from the intermediate portion. As illustrated in Figure 3, the dimension of the primary space 41 of the first portion 56 measured along the vertical direction is shorter than the dimension of the secondary space 37 of this first portion 56 also measured along of the vertical direction so that the primary space 41 does not entirely cover the secondary space 37. Similarly, the dimension of the primary space 41 of the second portion 58 measured along the transverse direction is shorter than the dimension of the secondary space 37 of this second portion 58 also measured along the transverse direction so that again, the primary space 41 does not entirely cover the secondary space 37

The first portion 56 of the angular junction piece 34 extends mainly in the main extension plane of the first side wall of the tank 30, so as to extend this first side wall of the tank. The first portion 56 has a first free edge 62 and a second free edge 64, these two free edges extending opposite to the intermediate portion 60 and being differentiated by the difference in length of the primary and secondary spaces. More particularly, the primary space 41 of the first portion 56 participates in forming the first free edge 62 and the secondary space 37 of the first portion 56 participates in forming the second free edge 64. In this way, the sealing membrane secondary 38 is discovered on the first portion 56 of the angular junction piece 34, from the first free edge 62 to the second free edge 64, and aims to be covered by the primary thermal insulation barrier 40 of the first side wall tank 30.

As mentioned above, and as illustrated more particularly in FIG. 4, the first portion 56 extends structurally and with a thickness similarly the first side wall of the tank 30 at least along the vertical axis C towards the intermediate portion 58. More particularly, the secondary space 37 constituting the first portion 56 extends, here vertically, the secondary space 37 constituting the the first side wall of the tank 30, and the primary space 41 constituting the first portion 56 extends in the same vertical direction the primary space 41 constituting the first side wall of the tank 30. In addition, the primary waterproofing membrane 42 and the secondary waterproofing membrane 38 are continuous between the first portion 56 of the angular junction piece 34 and the first side wall of the vessel 30. The second portion 58 of the angular junction piece 34 extends mainly in the plane. main extension of the second side wall of the tank 32, so as to extend this second side wall of the tank. What has just been described for the first portion 56 is found in the structure of the second portion 58, with a third free edge 68 and a fourth free edge 70 respectively formed by the primary space 41 and the secondary space 37 of this second portion 58.

Furthermore, the second portion 58 of the angular junction piece 34 extends structurally and with a similar thickness the second side wall of the tank 32 along the transverse axis B towards the intermediate portion 58. More particularly, the secondary space 37 constituting the second portion 58 extends, here transversely, the secondary space 37 constituting the second side wall of the tank 32 and the primary space 41 constituting the second portion 58 extends in the same transverse direction the primary space 41 constituting the the second side wall of the tank 32. In addition, the primary sealing membrane 42 and the secondary sealing membrane 38 are continuous between the second portion 58 of the angular junction piece 34 and the second side wall of the tank 32.

The first portion 56 and the second portion 58 of the angular junction piece 34 extend in planes perpendicular to each other. The first portion 56 is not adjacent to the second portion 58, due to the presence of the intermediate portion 60 of which the first portion 56 and the second portion 58 of the angular junction piece 34 are respectively integral. The first portion 56 is integral with the intermediate portion 60 at a first bonded edge 66, and the second portion 58 is integral with the intermediate portion 60 at the level of a second bonded edge 72.

The intermediate portion 60 extends mainly in an inclined plane which is on the one hand secant to the main plane of elongation of the first portion 56 and on the other hand secant to the main plane of elongation of the second portion 58. The edges linked 66, 72 previously mentioned form the junctions between each of the portions and each of the corresponding main planes.

Thus, according to the invention, the intermediate portion 60 forms an inclined wall relative to the two portions arranged respectively in the extension of one of the side walls of the vessel perpendicular to each other.

More particularly, in the example illustrated where a single intermediate portion 60 is arranged between the two portions 56, 58, the inclined plane in which the intermediate portion mainly extends has an angle of approximately 135 ° with, on the one hand, the first portion 56 and the first side wall 30 which it extends and on the other hand the second portion 58 and the second side wall 32 which it extends.

It follows from this arrangement of the different portions of the angular junction piece 34 that the dimension measured between the first portion 56 and the second portion 58 of the intermediate portion 60 increases from the internal face 27 towards the external face 29 of the sealed and thermally insulating tank 26. In other words, the dimension of the intermediate portion 60 between the first bonded edge 66 of the first portion 56 and the second bonded edge 72 of the second portion 58 at the level of the internal face 27 is smaller than the dimension of the intermediate portion between the first bonded edge 66 of the first portion 56 and the second bonded edge 72 of the second portion 58 at the outer face 29.

The purpose of the angular junction piece 34 according to the invention is to optimize the distribution of the pressure exerted by the liquid natural gas, the pressure being represented by an arrow D in FIG. 4, on the junction zones 24 of the constituent walls. of the plurality of tank walls of the sealed and thermally sealed tank insulating 26. The pressure exerted by the liquid natural gas present in the tank 26 on the internal face 27 at the level of the first portion 56 or of the second portion 58 is exerted on the corresponding first space 41 of the angular junction piece 34, and it is distributed in the direction of the outer face 29 over the whole of the corresponding second space 37, that is to say over a larger area. And the pressure exerted by the liquid natural gas on the internal face 27 of the intermediate portion 60 is distributed over the entire external face 29 of this intermediate portion 60, again of a larger dimension. The pressure forces of the liquid natural gas are distributed over a larger bearing surface at the level of the external face 29 intended to be in contact with the internal supporting structure 6.

As illustrated in FIG. 3, the angular junction piece 34 participates in forming an angular junction module 74, which can be arranged after other similar modules one after the other along a longitudinal axis A , corresponding to the axis common to the two side walls of the tank. Thus, the first portion 56, the second portion 58 and the intermediate portion 60 of each angular junction piece 34 is aligned with the first portion, the second portion and the intermediate portion of the other angular junction pieces 34 of a junction module angular 74.

Each angular junction module 74 includes a first longitudinal end 75 and a second longitudinal end 77. The sealing membrane 38 of the secondary space 37 is exposed at at least one of the longitudinal ends of the plurality of junction modules. angular 74.

As illustrated in Figure 4, each angular junction module 74 cooperates with the first tank wall 30 and the second tank wall 32. The first portion 56 of the angular junction pieces 34 of each angular junction module 74 is intended to be in contact with the first tank wall 30 at the level of the first free edge 62 and of the second free edge 64. Thus, the secondary space 37 of the first portion 56 of each part forming an angular junction module 74 is arranged in the continuity of the secondary space 37 of the first tank wall 30, the primary space 41 of the first portion 56 of each part forming each angular junction module 74 also being arranged in continuity of the primary space 41 of the first wall of the tank 30. The secondary space 37 of the first portion 56 of the parts forming each angular junction module 74, in its part not covered by the primary space, is covered with the primary space 41 of the first tank wall 30 up to the first free edge 62. And similarly, the secondary space 37 of the second portion 58 of each part forming an angular junction module 74 is arranged in the continuity of the the secondary space 37 of the second tank wall 32, and the primary space 41 of the second portion 58 of each part forming an angular junction module 74 is arranged in the continuity of the primary space 41 of the second tank wall 32. The secondary space 37 of the second portion 58 of the parts forming each angular junction module 74, in its part not covered by the primary space, is covered by the primary space 41 of the second tank wall 30 up to at the third free edge 6 8.

As a reminder, the side walls 30, 32 of the sealed and thermally insulating tank 26 rest directly on the bearing walls 18, 20 of the internal supporting structure 6. The same is true for the external face of the first and second portions of the angular junction piece which extend substantially perpendicular to each other. More precisely, the external face 29 of the first side wall of the tank 30 and the external face of the first portion 56 of the angular junction piece rest on the first bearing wall 18 of the internal supporting structure 6 by means of tubes of mastic not shown and on the other hand the external face 29 of the second side wall of the tank 32 and the external face of the second portion 58 of the angular junction piece rest on the second bearing wall 20 of the internal supporting structure 6 by means of mastic strands not shown.

The outer face 29 at the level of the intermediate portion 60, which extends in a plane inclined with respect to the main extension planes of the first and second side walls of the vessel, forms a chamfer and thus a clearance zone 76 between the portion. intermediate 60 and the internal supporting structure 6 at the junction zone 24. As illustrated in FIG. 4, the internal supporting structure 6 present in this junction zone 24, that is to say in the corner formed between the first bearing side wall 18 and the second bearing side wall 20 , a reinforcing element 78 which is arranged to be in contact with each of the bearing side walls and with the external face 29 of the intermediate portion 60. In other words, the internal supporting structure 6 is equipped with a bearing element. reinforcement 78 capable of filling the clearance zone 76. The reinforcement element 78 here takes on a triangular cross-section shape similar to that of the clearance zone, by presenting a contact face 80 capable of forming a stop for the movement of the portion. intermediate under the effect of the pressure exerted by the liquid natural gas present in the tank, and an opposite apex 82, having an angle substantially equal to 90 ° to come to match the wedge shape of the junction zone 24. Advantageously, the element nt of reinforcement 78 extends mainly along the longitudinal axis A, so as to form a reinforcement for each of the angular junction pieces 34. The reinforcement element 78 may in particular consist of a plate forming a longitudinal rib arranged at 135 ° each of the span walls of the internal load-bearing structure.

As more particularly visible in FIG. 4, the contact face 80 is opposite the intermediate portion 60 of the angular junction piece 34. In an original position, without pressure exerted on the angular junction piece by gas liquid, the reinforcing element 78 and the angular junction piece 34 participate in delimiting a space extending between the contact face 80 of the reinforcing element and the outer face 29 of the intermediate portion 60 of the junction piece angular 34. This space is here regular along two faces, that is to say a dimension measured between the contact face 80 and the outer face 29 of the intermediate portion 60 along an axis perpendicular to the main extension plane of the contact face 80 of the reinforcing element 78 and / or of the outer face 29 of the intermediate portion 60 is constant. In other words, the contact face 80 of the reinforcing element 78 and the outer face 29 of the intermediate portion 60 each extend in a plane parallel to the plane in which the other face is inscribed. The pressure exerted on the internal face 27 of the intermediate portion 60 by the liquid gas then implies a plane contact directly between the external face 29 of the intermediate portion 60 and the contact face 80 of the reinforcing element 78.

Thus, the external face 29 of the intermediate portion 60 of the plurality of angular junction pieces 34 rests on the reinforcing element 78. The pressure exerted by the liquid natural gas stored in the sealed and thermally insulating tank 26 on the internal face 27 of the intermediate portion 60 is then distributed more easily over the outer face 29 of each portion of the corresponding angular junction piece 34, the reinforcing element 78 forming at the level of the contact face a face substantially perpendicular to the general direction the pressure of the liquid natural gas in this junction zone 24 of the tank. The pressure exerted by the liquid natural gas stored in the sealed and thermally insulating tank 26 is thus better distributed and reduces the risk of the primary sealing membrane 42 appearing to leak.

Advantageously, this distribution of the pressure on various elements of the sealed and thermally insulating tank 26 and of the internal supporting structure 6 influences the concentration of stiffeners 8, 10 previously mentioned and more particularly the concentration of a first plurality of stiffeners 8 arranged between the outer shell 4 and the first bearing wall 18 of the internal supporting structure 6 and the concentration of a second plurality of stiffeners 10 arranged between the outer shell 4 and the second bearing wall 20 of the internal supporting structure 6.

As can be seen in particular in FIGS. 2 and 4, it is therefore less necessary to have stiffeners 8, 10 in the vicinity of the junction zone 24, and only a first stiffener 84, 90 of each plurality of stiffeners 8 , 10 may be in contact with the corresponding bearing wall 18, 20 of the internal bearing structure 6 at the level of the junction zone 24 while several stiffeners 86, 88, 92, 94 may be in contact with one of the walls bearing range 18, 20, at a distance from this junction zone 24. The concentration of stiffeners is thus reduced near the angular junction piece. For each plurality of stiffeners, respectively facing one or the other of the bearing walls 18, 20, a second stiffener 86, 92 is positioned between the first stiffener 84, 90 and a third stiffener 88, 94. By concentration of stiffeners reduced at the junction zone and the angular junction piece, it is understood that the distance separating the second stiffener 86, 92 and the third stiffener 88, 94 is smaller than the distance separating the second stiffener 86, 92 from the first stiffener 84, 90.

In the example illustrated in FIG. 4, the first stiffener 84, 90 of each plurality of stiffeners is in contact with the bearing side wall of the internal supporting structure 6 at the level of the reinforcing element 78, without this being limitative of the invention.

As illustrated in FIG. 7, and as can be seen in FIG. 2, this first stiffener 84, 90 can extend at the level of the junction zone at a distance from the reinforcing element and more particularly in a zone covered by the first portion or the second portion of the angular junction piece.

It is possible to define for each side wall 18, 20 of the vessel a proximal zone 101 and a distal zone 103 according to their arrangement with respect to the nearest junction zone 24, these two zones being delimited one with respect to the other by a demarcation in the extension of the free edge of the secondary space of the angular junction piece, namely the second free edge 64 for the first side wall of the tank 18 and the fourth free edge 70 for the second side wall of vessel 20. The proximal zone 101 consists of the zone extending between the junction zone 24 and this demarcation and the distal zone 103 consists of the zone moving away from the junction zone from this demarcation. As illustrated here in FIG. 7, only the first stiffener 84, 90 is advantageously located in the proximal zone 101, while several stiffeners 86, 88, 92, 94, are arranged in the distal zone 103. As described above- above, the distance between the first stiffener 84, 90 and the second stiffener 86, 92 is greater than the distance separating the second stiffener 86, 92 from the third stiffener 88, 94. The first stiffener 84 of the first plurality of stiffeners 8 can in particular be arranged in the transverse alignment of the first free edge 62 of the piece of angular junction 34 and the first stiffener 90 of the second plurality of stiffeners 10 can in particular be arranged in vertical alignment with the third free edge 68 of the angular junction piece 34.

As illustrated in Figure 7, at least a first stiffener of a plurality of stiffeners 8, 10 is positioned at a distance d from the corner of the internal load-bearing structure 6, i.e. from the top 82 of the. 'reinforcing element 78 and the first stiffener 84, 90. More particularly, in the example illustrated, each first stiffener of the plurality of stiffeners is arranged at this same distance d from the corner of the internal supporting structure 6.

According to one characteristic of the invention, the dimensions of the angular junction part are determined as a function of this positioning of the first stiffeners and of this distance d. More particularly, one can calculate a dimension D60 of the intermediate portion 60, measured along the outer face 29 of the intermediate portion 60 between the first bonded edge 66 and the second bonded edge 72, so that:

In the example illustrated, dimensions D56, D58 of the first portion 56 and of the second portion 58, respectively measured between the intermediate portion and a zone corresponding to the position of the corresponding first stiffener 84, 90, are equivalent to dimension D60 of the pre-determined intermediate portion. More particularly, a dimension D56 of the first portion 56, here measured vertically along the outer surface between the first bonded edge 66 and the zone of contact with the first stiffener 84 of the first plurality of stiffeners 8, that is to say ie to the right of the first free edge 62, has a value equivalent to the value of the dimension D60 of the intermediate portion. And a dimension D58 of the second portion 58, measured here transversely along the outer surface between the second bonded edge 72 and the area of contact with the first stiffener 90 of the second plurality of stiffeners 10, that is to say to the right of the third free edge 68, has a value equivalent to the value of the dimensions D60 and D56 previously mentioned. In this way, the forces exerted by the pressure of the liquid gas are more evenly distributed between the reinforcing element in the junction zone and each of the side walls of the tank and the stiffeners on which these side walls rest.

In a variant of the embodiments previously described and as illustrated in FIG. 8, the contact face 80 of the reinforcing element 78 has a shape distinct from the flat surface previously mentioned, forming a fillet 91 rather than a square corner. More particularly, the contact face 80 has an advantageously concave curvature, so that the space delimited between the contact face 80 of the reinforcing element 78 and the outer face 29 of the intermediate portion 60 is no longer constant and increases as one approaches the center of the intermediate portion 60. This space is filled by one or more shims 93, for example in the form of plywood panels and / or cylinders of wood for example, and / or by leveling material 95, such as mastic for example illustrated in FIG. 8 by a hatched zone, it being understood that this list is not exhaustive. It should be noted that the structure of the reinforcing element is easier to produce when it has a fillet and that it presents less risk of breakage at the junction with the bearing walls of the supporting structure under the effect of the pressure exerted by the liquid gas, the additional presence of reinforcing material filling the space making it possible to ensure the good transmission of the forces.

A variant embodiment of the invention will now be described with reference to FIGS. 5 and 6. Each angular junction module 74 which has been described above is provided to ensure the junction between the first tank wall 30 and the second. tank wall 32 of the sealed and thermally insulating tank 26. However, it is not excluded that the tank 26 has other tank walls and that the angular junction modules 74 according to the invention are configured to be positioned in further facing a second junction zone of the vessel walls.

In this example, the plurality of vessel walls further comprises a third vessel wall, or first transverse vessel wall 96, extending in a plane. perpendicular to the first side wall 30 and perpendicular to the second side wall 32. Furthermore, this first transverse tank wall 96 is perpendicular to the main axis of extension of the plurality of angular junction pieces 34, that is- i.e. the longitudinal axis A.

It is understood that according to the invention, each wall of the sealed tank 26 can be connected to another wall of the sealed tank 26 by an angular junction module 74. According to the example described here, the junction between the third tank wall 96 and the first vessel wall 30 may have an angular junction module 74, just like the junction between the third vessel wall 96 and the second vessel wall 32.

In this context, the sealed and thermally insulating tank 26 according to the invention comprises an angular junction element 98 which differs from the angular junction piece 34 in the presence of a return part.

As illustrated in FIG. 5, the angular junction element 98 comprises a first part 100 and a second part 102. Each of the two parts 100 and 102 has a structure substantially equivalent to what has just been described, namely , from an external face 29 towards an internal face 27, a secondary space 37, comprising the secondary thermal insulation barrier 36 and the secondary waterproofing membrane 38, and a primary space 41, comprising the primary thermal insulation barrier 40 and the primary waterproofing membrane 42.

As a reminder, the secondary thermal insulation barrier 36 comprises, from the external face 29 towards the internal face 27, the insulation wall 44 covered with the first layer of thermal insulation 46, then with the second insulation wall 51 present specifically in the angular junction element in accordance with what has been described above for the angular junction piece. This secondary thermal insulation barrier 36 ensures a first maintenance of the temperature inside the sealed and thermally insulating tank 26, advantageously when liquid natural gas is stored there. The secondary thermal insulation barrier 36 is covered by the secondary waterproofing membrane 38. The secondary sealing membrane 38 ensures the conservation of the liquid natural gas stored in the sealed and thermally insulating tank 26 when a leak of liquid natural gas occurs in the primary space 41.

The secondary waterproofing membrane 38 includes a flexible secondary waterproofing membrane 48 overlying a plurality of rigid secondary waterproofing membranes 49.

The triplex strip forming the first flexible waterproofing membrane 48 is intended to be bonded on the one hand to the rigid secondary waterproofing membranes 49, and more particularly to cover the junction areas of these rigid membranes, and on the other hand to the primary thermal insulation barrier 40, thus preventing contamination at the various junctions. The primary thermal insulation barrier 40 thus comprises, from the external face 29 towards the internal face 27, the second layer of thermal insulation 52 and the third insulation wall 54. The primary thermal insulation barrier 40 is covered by the primary waterproofing membrane 42.

As specified above, the angular junction element 98 comprises a first part 100 and a second part 102. The first part 100 of the angular junction element 98 is provided to align and cooperate with the plurality of parts or angular junction modules 34, 74, as well as with the first side wall of tank 30 and the second side wall of tank 32. The second part 102 of the angular junction element 98 is formed perpendicular to the first part 100 so to extend opposite the first transverse vessel wall 96.

The first part 100 of the angular junction element 98 comprises, as for the angular junction part 34, a first section 104, a second section 106 and at least one intermediate section 108.

The first section 104 of the angular junction element 98 extends mainly in a plane parallel to the main extension plane of the first side wall of the tank 30 and of the first portion 56 of the angular junction pieces 34 and as before, primary space 41 and space secondary 37 do not have the same dimensions, both with respect to the longitudinal axis A and with respect to the vertical axis C, it being understood that the main extension plane of the first side wall of tank 30 extends here longitudinally and vertically.

The first section 104 has a first free end edge 110 and a second free end edge 112, these end edges being perpendicular to each other. The secondary space 37 of the first section 104 is not covered with the primary space 41 in the vicinity of the first free end edge 110 and in the vicinity of the second free end edge 112.

The second section 106 has a shape equivalent to that of the first section 104, with a third free end edge 116 and a fourth free end edge 118. Again, the secondary space 37 is not covered by the. 'primary space 41 in the vicinity of the third and fourth free end edge.

The first section 104 and the second section 106 of the angular junction member 98 extend mainly in planes perpendicular to each other. The first section 104 is not adjacent to the second section 106, due to the presence of the intermediate section of which the first section 104 and the second section 106 are respectively secured at a respective linked side 114, 120.

The intermediate section 108 extends mainly in an inclined plane, secant on the one hand to the main elongation plane of the first section 104 and on the other hand to the main elongation plane of the second section 106. The secant plane is parallel to the longitudinal axis A and is oriented so as to advantageously present an angle of approximately 135 ° with each of the main elongation planes mentioned above. The intermediate section 108 is thus secant to the first section 104 advantageously at an angle of about 135 ° while also being secant to the second section 106, advantageously at an angle of about 135 °. The secondary space 37 is not covered with the primary space 41 at the level of a fifth free side 115 of the intermediate section 108. Indeed, the primary space 41 and the secondary space 37 do not extend. on the same length along the longitudinal axis A. The primary space 41 is shorter than the secondary space 37 along the longitudinal axis A towards the fifth free side 115 of the intermediate section 108. Thus, the secondary waterproofing membrane 38 is uncovered at the fifth free side 115 without any superimposed and / or glued element.

Here again, the intermediate section 108 has a dimension which increases as it moves away from the internal face 27, in particular in order in particular to best distribute the pressures exerted by the liquid natural gas present in the tank, such as that cal could be described previously. And it should be noted that in this variant embodiment, the intermediate section 108 is again facing a clearance zone which can be filled with a reinforcing element against which the junction element rests at the level of the outer face of the intermediate section. In addition, the reinforcing element can have a contact face extending in a plane or forming a fillet, as described above, the intermediate section 108 being able to include shims and / or patching material to fill. the space between the outer face 29 and the contact face of the reinforcing element.

The second part 102 of the junction element 98 extends mainly in a plane perpendicular to the longitudinal axis A, that is to say in a plane perpendicular to each of the sections of the first part 100 of the element junction. In other words, the second part 102 of the angular junction element 98 forms a deflection part which extends perpendicularly the first part 100 of the angular junction element 98.

More particularly, the second part 102 comprises a return wall 121 having a free transverse side 122, a linked transverse side 124, a free vertical side 126 and a linked vertical side 128. The free transverse side 122 and the linked transverse side 124. 'extend along a transverse axis B, perpendicular to the longitudinal axis A and the vertical axis C, while the free vertical side 126 and the side vertical linked 128 extend along the vertical axis C. The second part 102 is integral with the first part 100 at the level of the linked transverse side 124 and the linked vertical side 128.

The secondary space 37 is not covered with the primary space 41 at the level of the free transverse side 122 and of the free vertical side 126 of the second part 102 of the angular junction element 98. Indeed, the primary space 41 and the secondary space 37 do not extend the same length along the transverse axis B and along the vertical axis C. As before, the primary space 41 is shorter than the secondary space 37, here along the transverse axis B to the free vertical side 126 and also shorter along the vertical axis C to the free transverse side 122.

The purpose of the angular junction element 98 according to the invention is to optimize the distribution of the pressure exerted by the liquid natural gas on the junction zones of the constituent walls of said tank 26, in particular by the shape of the intermediate section 108 and the clearance zone between this intermediate section and the junction zone of the bearing walls 18, 20, while providing a connection between the first transverse vessel wall 96 and the plurality of angular junction modules 74. The pressure exerted by the gas natural liquid stored in the sealed and thermally insulating tank 26 on the internal face 27 at the level of the intermediate section 108 of the angular junction element 98 is distributed over the whole of the angular junction element 98, and up to the return wall 121 which extends opposite the first transverse wall of the tank 96.

The primary space 41 of the first part 100 and the primary space of the second part 102 of the angular junction element 98 can be one piece. In particular, the primary sealing membrane 42 at the first part 100 can be welded to the primary sealing membrane 42 of the second part 102, or be made as a single element.

As shown in Figure 6, the first part 100 of the angular junction element 98 is intended to be in contact with an angular junction piece 34 of an angular junction module 74. The first portion 56, the second portion 58 and the intermediate portion 60 of the closest angular junction module 74 of the angular junction element 98 align respectively with the first section 104, the second section 106 and the intermediate section 108 of the first part 100 of the angular junction element 98. More particularly, the secondary space 37 of the angular junction element 98 is in contact with the secondary space of this angular junction module 74. To secure the angular junction element 98 to this angular junction module 74, primary space panels 41, here not shown, are fixed by gluing and welding on the secondary space 37 between the primary space 41 associated with the angular junction module 74 and the primary space 41 associated with the angular junction element 98.

The first section 104 of the angular junction element 98 and the first portion 56 of the angular junction pieces 34 are intended to be in contact with the first side wall of the vessel 30. The fixing of the angular junction element 98 and the angular junction pieces 34 to the first side wall of the tank 30 is carried out in a similar way to the fixing of the angular junction element 98 with the nearest angular junction module 74. A panel of the primary space 41 is glued and welded at the connection between the first side wall of the vessel 30 and the angular junction element 98 and the plurality of angular junction pieces 34.

The second section 106 of the angular junction element 98 and the second portion 58 of the angular junction pieces 74 are intended to be in contact with the second side wall of the tank 32. The fixing of the angular junction element 98 and the angular junction pieces 34 to the second side wall of the tank 32 is carried out in a manner similar to the fixing of the angular junction element 98 with the nearest angular junction module 74. A panel of the primary space 41 is glued and welded at the connection between the second vessel side wall 32 and the angular junction element 98 and the plurality of angular junction pieces 34.

The first lateral vessel wall 30, respectively the second lateral vessel wall 32, and the first transverse vessel wall 98 are integral with one another via a first conventional junction element 130, respectively a second conventional junction element. 132, produced in a known manner. The first conventional junction element 130 and the second conventional junction element 132 each have two parts. Each of the parts of the junction elements are perpendicular to each other, and each extends in a main extension plane of one of the vessel walls described above. The angular junction element 98 is thus in contact with at least one of the ends of at least one conventional junction element 130. In the example illustrated, the angular junction element 98 is in contact on the one hand. with the closest angular junction module 74, and on the other hand with the first conventional junction element 130 and with the second conventional junction element 132. According to an alternative embodiment not illustrated, a sealed tank according to the invention can be made so that the third wall, or first transverse wall 96, perpendicular to the first side wall 30 and to the second side wall 32, is linked to each of these walls by an angular junction module 74. In this context, the The angular junction element 98 arranged at the junction of these three walls is particular in that an intermediate portion similar to what has been previously described is arranged between sections of the angular junction element arranged in s the extension of each of the walls. The angular junction element thus being adapted to present at each junction of two walls a shape similar to the first part as described above, it should be noted that the reinforcement 78 provided to fill the clearance between the angular junction element and the internal supporting structure 6 this time has a pyramidal shape.

Claims

1. Leaktight tank (26) and thermally insulating, able to rest on a supporting structure (6) of a ship, the sealed tank (26) comprising a plurality of tank walls including a first tank wall (30) and least a second vessel wall (32), the first vessel wall (30) extending mainly in a first plane and the second vessel wall (32) extending mainly in a second plane, the first plane and the second plane being perpendicular to each other, the first vessel wall (30) and the second vessel wall (32) being linked by an angular junction piece (34), characterized in that the junction piece angular (34) has a first portion (56) extending mainly in the first plane, a second portion (58) extending mainly in the second plane and at least one intermediate portion (60) extending mainly in a plane secant in the foreground and in the second plane, the first portion (56) of the angular junction (34) having a thickness equivalent to that of the first tank wall (30) and extending in the extension of this first tank wall (30) and the second portion (58) of the angular junction piece ( 34) having a thickness equivalent to that of the second tank wall (32) and extending in the extension of this second tank wall (32).

2. Leaktight tank (26) according to claim 1, the sealed tank (26) comprising at least one third tank wall (96) extending mainly in a third plane perpendicular to the first plane, to the second plane and to the secant plane, and having a junction area with the first vessel wall (30) and the second vessel wall (32), wherein the junction area comprises an angular junction element (98), the angular junction element (98) comprising a first part (100) and a second part (102), the first part (100) having a first section (104) extending mainly in the first plane, a second section (106) extending mainly in the second plane and an intermediate section (108) extending mainly in the secant plane, the second part (102) having a deflection wall (121) perpendicular to the first part (100) and extending mainly in the third plane.

3. sealed tank (26) according to claim 1 or 2, wherein the part of angular junction (34) and / or the angular junction element (98) each have an internal face (27) and an external face (29), the internal face (27) forming an internal chamfer at the level of the intermediate portion ( 60) or at the level of the intermediate section (108) and the external face (29) forming an external chamfer at the level of the intermediate portion (60) or at the level of the intermediate section (108), the internal and external chamfer s' tilting at an angle between 120 ° and 150 ° with respect to the foreground and the second plane.

4. sealed vessel (26) according to claim 3, wherein the dimension of the intermediate portion (60) of the angular junction piece (34) measured between the first portion (56) and the second portion (58) of said piece. (34), and / or the dimension of the intermediate section (108) of the angular junction element (98) measured between the first section (104) and the second section (106) of said angular junction element (98), grows from the inner face (27) to the outer face (29).

5. Leakproof vessel (26) according to any one of the preceding claims, wherein the angular junction piece (34) and / or the angular junction element (98) successively comprise in the direction of the thickness from the outside towards the inside of the tank, a secondary thermally insulating barrier (36) capable of being in contact with the supporting structure (6), a secondary waterproofing membrane (38) carried by the secondary thermally insulating barrier (36), a primary thermally insulating barrier (40) resting against the secondary waterproofing membrane (38) and a primary waterproofing membrane (42) carried by the primary thermally insulating barrier (40) and intended to be in contact with the fluid contained in the sealed tank (26).

6. Sealed tank (26) according to claim 5, wherein the secondary thermally insulating barrier (36) and the secondary sealing membrane (38) of the angular junction piece (34) and / or the angular junction element (98) have, in a given direction, a larger dimension than the corresponding dimension, in the same direction, of the primary thermally insulating barrier (40) and of the primary waterproofing membrane (42).

7. sealed tank (26) according to one of the preceding claims, in in which the dimension (D56, D58) of the first portion (56) and / or of the second portion (58) of the angular junction piece (34) has a value equivalent to that of the dimension (D60) of the intermediate portion (60).

8. Vessel (200) comprising at least one sealed tank (26) according to any one of the preceding claims.

9. Ship according to claim 8, comprising an outer hull (4) and a supporting structure (6), the supporting structure (6) being intended to house the sealed tank (26), the supporting structure (6) having a first wall. bearing wall (18) extending mainly along the first plane and a second bearing wall (20) extending mainly along the second plane, the first bearing wall (18) and the second bearing wall (20) being substantially perpendicular, characterized in that a clearance zone is provided between the bearing walls of the supporting structure in the junction zone (24) and the intermediate portion (60) of the angular junction piece (34) and in that a reinforcing element (78) is housed in said clearance zone.

10. Vessel according to claim 9, wherein the reinforcing element (78) is of triangular shaped section, the reinforcing element (78) having a vertex (82) whose angle is equivalent to the right angle. formed between the first bearing wall (18) and the second bearing wall (20), the reinforcing element having a contact face (80) with the intermediate portion (60) which is opposite this apex.

11. A vessel according to claim 10, wherein the contact face (80) has a faceted profile, being formed of a plurality of flat surfaces inclined with respect to each other so as to tend towards a profile curved towards the sea. 'interior of the reinforcing element (78).

12. A vessel according to claim 10, wherein the contact face (80) has a curved profile so as to generate a generally concave shape of the reinforcing element (78).

13. Ship according to one of claims 9 to 12, the outer shell (4) having a plurality of stiffeners (8, 10) in contact with the supporting structure (6), wherein the concentration of stiffeners (8, 10) is reduced near the angular junction piece (34) and / or near the angular junction element (98).

14. Ship according to the preceding claim, wherein a dimension (D60) of the intermediate portion (60) of the angular junction piece (34) is determined as a function of the position of the stiffener (84, 90) closest to a corner of the supporting structure (6) in which the angular junction piece (34) is positioned.

15. A method of loading or unloading a liquid natural gas from a tank (26) according to claims 1 to 7 or from a vessel (200) of liquid natural gas according to one of claims 8 to 14.