EP3942219B1 - Thermally insulating sealed tank - Google Patents

Description

Technical area

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 serving as fuel for the propulsion of the floating structure.

In one embodiment, the liquefied gas is LNG, namely a mixture with a high methane content stored at a temperature of approximately -162° C. at atmospheric pressure. Other liquefied gases can also be considered, in particular ethane, propane, butane or ethylene. Liquefied gases can also be stored under pressure, for example at a relative pressure of between 2 and 20 bar, and in particular at a relative pressure close to 2 bar.

Technology background

The document WO2014096600 discloses a sealed and thermally insulating tank for storing liquefied natural gas arranged in a support structure and whose walls have a multilayer structure, namely from the outside towards the inside of the tank, a secondary thermally insulating barrier anchored against the structure carrier, a secondary waterproof membrane which is supported by the secondary thermally insulating barrier, a primary thermally insulating barrier which is placed on the secondary waterproof membrane and a primary waterproof membrane which is supported by the primary thermally insulating barrier and which is intended to be in contact with the liquefied natural gas stored in the tank.

Each thermal insulation barrier, primary and secondary, comprises a set of insulating panels, respectively primary and secondary, of generally parallelepiped shape which are juxtaposed and which thus form a support surface for a respective waterproof membrane. Insulation panels are anchored to the structure by means of anchoring devices which are fixed to the supporting structure and which are positioned at the level of the corners of the primary and secondary insulating panels. Each anchoring device thus cooperates with the corners of four adjacent secondary insulating panels and with the corners of four adjacent primary insulating panels in order to retain them against the supporting structure.

The document WO2013104850 describes a sealed and thermally insulating tank comprising a multilayer structure in which the corners of the insulating panels of the primary thermally insulating barrier are not located in alignment with the corners of the insulating panels of the secondary insulating barrier. In such a tank, primary anchoring devices cooperating with the primary insulating panels are fixed on a plate anchored in a secondary insulating panel. Thus, the primary anchoring devices and the primary insulating panels are anchored to the supporting structure via the secondary insulating panels.

In all cases, the secondary insulating panels are liable to deform and/or move. Indeed, the secondary insulating panels are subjected to thermal gradients which, due to the phenomena of differential contraction, are likely to cause them to bend. In addition, the deformation of the supporting structure causes deformations and/or displacements of the secondary insulating panels. This is particularly the case when the load-bearing structure is formed by the inner hull of a floating structure. In addition, if it delimits ballast compartments, the movements of the ballast liquid in the ballast compartments are also likely to cause significant deformations of the supporting structure and therefore deformations and/or displacements of the secondary insulating panels. anchored to said supporting structure.

Furthermore, the movements of the liquid contained in the tank can generate stresses on the primary sealed membrane, in particular if the latter comprises protruding parts such as undulations. These stresses affect the primary insulating panels on which the primary waterproof membrane is anchored and tend to move the primary insulating panels laterally. This causes stress concentrations at the primary anchoring devices.

However, in order to ensure the sealing of the secondary sealed membrane, the primary anchoring devices comprise a collar welded in a sealed manner to the secondary sealed membrane. This flange is fixed rigidly to a stud carrying a support member cooperating with the corresponding primary insulating panel or panels. During deformations and/or displacements of the insulating panels and/or movements of the primary insulating panels, this connection between the primary anchoring devices and the secondary waterproof membrane is liable to produce a concentration of stresses at the level of the weld between the collar and the secondary waterproof membrane, liable to cause damage to said weld and said secondary waterproof membrane.

In particular, in the case of primary anchoring devices fixed in a secondary insulating panel, the deformation and/or displacements of the secondary insulating panels generate displacements of the primary anchoring device. These displacements of the primary anchoring device have repercussions at the level of the flange rigidly fixed to the stud and generate stresses at the level of the sealed connection between the flange and the secondary sealed membrane. Such stresses can degrade the secondary sealed membrane and/or the sealed connection between the collar and the secondary sealed membrane and therefore degrade the tightness of the secondary sealed membrane.

Summary

One idea underlying the invention is to limit the stress concentrations at the connections between the secondary waterproof membrane and the primary anchoring member of the primary insulating panels. One idea at the base of the invention is to produce a sealed and flexible connection between the primary anchoring member and the secondary sealed membrane. Thus, an idea underlying the invention is to allow relative movement between the secondary waterproof membrane and the primary anchoring member. An idea underlying the invention is to allow this movement whether the primary anchoring member is anchored to the load-bearing structure directly, for example by being produced jointly with the secondary anchoring member, or indirectly, for example by being fixed on a secondary insulating panel. Thus, another idea underlying the invention is to allow relative movement between a secondary insulating panel on which is fixed a primary anchoring member and the secondary waterproof membrane.

• la barrière isolante primaire comportant une pluralité de panneaux isolants primaires juxtaposés,
• la cuve comportant en outre une pluralité d'organes d'ancrages primaires destinés à être retenus, directement ou indirectement, sur la paroi porteuse, chacun desdits organes d'ancrages primaires coopérant avec au moins un panneau isolant primaire de la pluralité de panneaux isolants primaires de manière à retenir ledit au moins un panneau isolant primaire sur la membrane étanche secondaire,
• dans laquelle un, plusieurs ou chaque dit organe d'ancrage primaire comporte :
  • une base destinée à être retenue, directement ou indirectement, sur la paroi porteuse,
  • une tige se développant selon la direction d'épaisseur de la paroi de cuve depuis ladite base vers la membrane étanche primaire, ladite tige traversant un orifice de la membrane étanche secondaire,
  • un élément d'appui monté sur la tige, ledit élément d'appui étant en appui sur un panneau isolant primaire de manière à retenir ledit panneau isolant primaire sur la membrane étanche secondaire,
  • une rondelle d'étanchéité engagée sur la tige entre l'élément d'appui et l'orifice de la membrane étanche secondaire, la rondelle d'étanchéité présentant un orifice central traversé par la tige, la rondelle d'étanchéité étant fixée de manière étanche à la membrane étanche secondaire, par exemple par une collerette de la rondelle d'étanchéité, autour de l'orifice de ladite membrane étanche secondaire,
  • un joint déformable reliant de façon étanche ladite rondelle d'étanchéité et la tige de manière à autoriser un déplacement relatif entre la rondelle d'étanchéité et la tige..

According to one embodiment, the invention provides a sealed and thermally insulating tank comprising a tank wall, the tank wall comprising, successively from the outside of the tank towards the inside of the tank in a direction of thickness of the vessel wall, a secondary insulating barrier intended to be anchored to a load-bearing wall, a secondary sealed membrane resting on the secondary insulating barrier, a primary insulating barrier resting on the secondary sealing membrane and a primary sealing membrane resting on the primary insulating barrier and intended to be in contact with a product contained inside the tank,

• the primary insulating barrier comprising a plurality of juxtaposed primary insulating panels,
• the tank further comprising a plurality of primary anchoring members intended to be retained, directly or indirectly, on the load-bearing wall, each of said primary anchoring members cooperating with at least one primary insulating panel of the plurality of primary insulating panels so as to retain said at least one primary insulating panel on the secondary waterproof membrane,
• wherein one, several or each said primary anchor member comprises:
  • a base intended to be retained, directly or indirectly, on the load-bearing wall,
  • a rod developing along the thickness direction of the vessel wall from said base towards the primary sealed membrane, said rod passing through an orifice of the secondary sealed membrane,
  • a support element mounted on the rod, said support element resting on a primary insulating panel so as to retain said primary insulating panel on the secondary waterproof membrane,
  • a sealing washer engaged on the rod between the support element and the orifice of the secondary sealed membrane, the sealing washer having a central orifice through which the rod passes, the sealing washer being fixed in a sealed manner to the secondary waterproof membrane, for example by a flange of the sealing washer, around the orifice of said secondary waterproof membrane,
  • a deformable gasket sealingly connecting said sealing washer and the rod so as to allow relative movement between the sealing washer and the rod.

Thanks to these characteristics, a relative movement between the secondary waterproof membrane and the primary anchoring member is possible without risk of degradation of the secondary waterproof membrane or of the waterproof connection between the primary anchoring member and the secondary waterproof membrane. . In particular, the deformable seal provides a leaktight and flexible connection between, on the one hand, the stem of the primary anchoring member and, on the other hand, the sealing washer ensuring the sealing of the secondary leaktight membrane. Such a primary anchoring member thus allows relative movements between the secondary and/or primary insulating panels and the secondary waterproof membrane, without risk of degradation of the secondary waterproof membrane or of the connection between the primary anchoring member and said secondary waterproof membrane.

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

The primary anchoring member described above can be used on an entire vessel wall or only in localized portions of the vessel wall such as the ballast zones. According to one embodiment, the vessel wall has a vertical component defining a height of said vessel wall in the direction of earth's gravity, the vessel wall comprising several of said primary anchoring members each comprising a base, a rod, a support element, a sealing washer and a deformable gasket as above, said several primary anchoring members being arranged on a lower portion of the vessel wall, for example at least the lower two thirds of the height of said tank wall.

According to one embodiment, the vessel wall is a first vessel wall, the vessel further comprising a second vessel wall, the first vessel wall and the second vessel wall forming an edge of the vessel, the first vessel wall tank comprising several of said primary anchoring members each comprising a base, a rod, a support element, a sealing washer and a deformable seal as above, said several primary anchoring members being arranged at a distance of the edge of the tank lower than a predefined threshold. For example, the predefined threshold corresponds to the width of five insulating panels, said several primary anchoring members being for example arranged to retain five successive primary insulating panels in a direction perpendicular to the edge.

The portions of the walls of the tank located in the lower portion of the tank are subject to particularly high stresses, due for example to the weight of the transported liquid or, for example, in the context of the walls of transverse tanks anchored on the walls of cofferdam, due to the ship's ballast. Similarly, the edge zones of the tank are also subject to particularly high stresses, including the pressure generated by the water in the ship's ballast. These stresses are likely to generate relative displacements between, on the one hand, the primary insulating barrier and/or the secondary insulating barrier and, on the other hand, the secondary sealed membrane at the level of the lower portion of the vessel and/or the edges of the tank. Thus, thanks to the arrangement of said primary anchoring members, the risks of degradation of the secondary sealed membrane are limited due to the flexibility of the connection between said primary anchoring members and the secondary sealed membrane.

Primary insulation panels can be made in various ways. According to one embodiment, the primary insulating panels are parallelepipedic in shape.

According to one embodiment, the primary insulating panels comprise a bottom plate, a cover plate and an insulating gasket inserted between the bottom plate and the cover plate.

The support element can be supported on various portions of the primary insulating panels. According to one embodiment, the support element is supported directly on said primary insulating panel, for example by being supported on the bottom plate of said primary panel. According to one embodiment, the support element bears indirectly on the primary insulating panel, for example by means of a wedge inserted between said support element and an element of the primary insulating panel, for example the bottom plate of the primary insulation panel.

According to one embodiment, the corners of the primary insulating panels have recesses, said recesses releasing a support surface facing the inside of the tank. According to one embodiment, the support element of the primary anchoring member bears, directly or indirectly, on the support surface of the primary insulating panel. According to one embodiment, said recesses are made in the cover plate and in the insulating gasket. According to one embodiment, the bearing surface is formed by a portion of the bottom plate projecting from the recess made in the insulating gasket and in the cover plate. According to one embodiment, the support surface is formed by a wedge placed between the support element and a portion of the bottom plate projecting from the recess made in the insulating gasket and in the cover plate.

According to one embodiment, a said primary anchoring member cooperates with the corners of adjacent primary insulating panels, for example four panels whose corners are adjacent, so as to anchor said adjacent primary panels to the load-bearing wall.

The sealing washer can be attached to the secondary sealing membrane in various ways. According to one embodiment, the sealing washer or the flange is welded in a sealed manner to the secondary sealed membrane.

According to one embodiment, the deformable seal is deformable in a direction of thickness of the vessel wall so as to allow sliding of the sealing washer along the rod in a direction of thickness of the vessel wall .

According to one embodiment, the central orifice of the sealing washer has a transverse dimension greater than the transverse dimension of a portion of rod engaged in said central orifice, so as to allow movement of the rod in said central orifice of the sealing washer in a direction perpendicular to the thickness direction of the vessel wall. Such a sealing washer allows freedom of movement of the sealing washer relative to the rod in a direction perpendicular to the direction of thickness of the vessel wall. More particularly, such a primary anchoring member allows movement of the sealed connection between the sealing washer and the secondary sealed membrane with respect to the support element mounted on the rod and cooperating with the primary insulating panel(s). . Thus, any displacements of the secondary and/or primary insulating panels in a plane perpendicular to the thickness direction of the vessel wall are not transmitted to the secondary sealed membrane via the primary anchoring member, thus reducing the stresses linked to the differential contraction, to the deformation of the load-bearing wall or even to the movements of liquid in the tank, and limiting the risk of degradation of the secondary sealed membrane or of the sealed connection between the sealing washer and the secondary waterproof membrane.

According to one embodiment, the primary anchoring member further comprises an abutment carried by the rod, said abutment being arranged on the rod between the support element and the sealing washer, the abutment having a surface of abutment vis-à-vis the sealing washer in order to stop movement towards the primary sealed membrane in the direction of thickness of the vessel wall of said sealing washer with respect to the rod.

Thanks to these characteristics, the deformations of the secondary sealed membrane along the thickness direction of the vessel wall are limited at the level of the sealed connection between the sealing washer and the orifice of the secondary sealed membrane. In particular, in the event of overpressure in the secondary insulating barrier or even of deformation of the secondary insulating barrier, the deformation of the secondary sealed membrane is prevented along a thickness direction of the vessel wall. Indeed, the sealing washer being fixed in a sealed manner to the secondary sealed membrane around the orifice of the secondary sealed membrane, in the presence of a force tending to move the secondary sealed membrane towards the inside of the tank, the local deformation of the secondary sealed membrane at the level of the sealed connection with the sealing washer is blocked by the abutment of the sealing washer against the abutment surface. Thus, the risks of degradation of the secondary waterproof membrane, for example by puncturing, are reduced. In addition, this limitation of local deformations of the secondary sealed membrane makes it possible to limit the risks of degradation of the deformable seal.

According to one embodiment, the rod carries a shoulder, said shoulder protruding laterally from the rod, that is to say in a direction perpendicular to the longitudinal direction of the rod, beyond the central orifice of the sealing washer so that an outer face of said shoulder forms the abutment surface. Such a stop is simple to make without requiring any additional part.

According to one embodiment, the primary anchoring member further comprises a bell mounted on the rod, said bell comprising a mounting portion and a protective portion, the mounting portion having a central passage through which the rod passes, the protective portion developing along the thickness direction of the vessel wall from the mounting portion towards the flange of the sealing washer, the protective portion being hollow, the deformable gasket being partially or totally housed in the protection. Such a bell surrounding the stem of the primary anchoring member makes it possible to protect the stem and the deformable seal.

According to one embodiment, the mounting portion of the bell comprises a plate developing in a plane perpendicular to the direction of thickness of the vessel wall, said plate comprising the through passage of the bell.

According to one embodiment, the deformable seal is completely housed in the protective portion of the bell. Thus, the deformable seal is protected by the bell, for example during assembly operations of the primary anchoring member in the vessel. According to one embodiment, the deformable seal is fixed on the rod between the passage of the mounting portion of the bell and the sealing washer.

According to one embodiment, the end of the protection portion opposite to the mounting portion of the bell comprises a flange developing radially outwards, an outer face of said flange forming the abutment surface in order to stop a displacement of the sealing washer along the thickness direction of the vessel wall.

According to one embodiment, an outer end of the protective portion opposite to the mounting portion forms the abutment surface facing the sealing washer in order to stop movement of the sealing washer in the direction thickness of the vessel wall.

According to one embodiment, the bell is fixed on the stem. Thus, the abutment surface can be formed by the protective portion having a fixed position relative to the rod and making it possible to block the movement of the sealing washer relative to the rod. According to one embodiment, the mounting portion of the bell is welded to the stem.

According to one embodiment, the deformable seal comprises a deformable bellows, said deformable bellows being hollow and developing around and axially along the rod, a first axial end of said bellows being fixed in leaktight manner on the rod and a second axial end of said bellows being fixed in leaktight manner to the sealing washer. Such a deformable seal in the form of a bellows is simple to produce and allows a sealed deformation of said deformable seal in a satisfactory manner. Such a bellows can be made of many materials. According to one embodiment, the bellows is made of stainless steel. Such a stainless steel bellows, or stainless steel, is thin enough to allow its elastic deformation. In one embodiment, the bellows is made of stainless steel with a thickness comprised between 0.1 mm and 0.5 mm, for example comprised between 0.1 mm and 0.3 mm.

According to one embodiment, the bellows has a plurality of folds having an identical or increasing diameter, a central portion of the bellows formed by said plurality of folds thus having a substantially cylindrical shape of revolution.

According to one embodiment, the bellows has at least three folds or waves, preferably between three and thirty-two folds, ideally between six and twenty-four folds.

According to one embodiment, the bellows is of flared shape, the second axial end of the bellows fixed to the sealing washer having a circumferential dimension greater than the circumferential dimension of the first axial end of the bellows fixed to the rod.

According to one embodiment, the bellows has a plurality of folds whose diameter increases from the end anchored on the rod towards the end anchored on the sealing washer. Thus, the portion of the bellows formed by this plurality of folds has a conical shape, the largest dimension of which is located on the side of the end fixed to the sealing washer.

According to one embodiment, the sealing washer has an internal surface developing in a plane perpendicular to the direction of thickness of the vessel wall. According to one embodiment, the internal surface is arranged opposite the abutment surface so as to cooperate with said abutment surface, which for example forms part of the bell or of the stem, to block the movement of the sealing washer relative to the rod in the thickness direction of the tank.

According to one embodiment, the deformable seal is fixed on the internal surface of the sealing washer, for example on a radially outer portion of the internal surface of the sealing washer.

According to one embodiment, the sealing washer comprises a rib protruding from the internal surface of the sealing washer, the deformable gasket being fixed in leaktight manner on said rib. According to one embodiment, the rib of the sealing washer develops from a radially internal portion of the internal surface of the sealing washer.

According to one embodiment, the tank comprises a plurality of secondary anchoring members, each secondary anchoring member being intended to be anchored on the load-bearing wall and cooperating with the secondary insulating barrier so as to exert a bearing on said barrier secondary insulation in the direction of the bearing wall when said secondary anchoring member is anchored to said bearing wall.

According to one embodiment, the base of the primary anchoring member is anchored to a secondary anchoring member.

According to one embodiment, the base of the primary anchoring member is rigidly anchored in the secondary insulating barrier. In this case, the primary anchoring member is retained on the load-bearing wall by means of the secondary insulating barrier.

According to one embodiment, the secondary insulating barrier comprises a plurality of juxtaposed secondary insulating panels. According to one embodiment, one, several or each secondary insulating panel comprises a bottom plate, a cover plate and an insulating gasket inserted between the bottom plate and the cover plate, the secondary waterproof membrane resting on an internal face of the cover plate opposite the insulating gasket. According to one embodiment, one, several or each secondary insulating panel comprises an intermediate plate interposed between the cover plate and the bottom plate of said secondary insulating panel, the insulating gasket of said secondary insulating panel comprising an external insulating gasket interposed between the plate bottom and the intermediate plate and an internal insulating gasket interposed between the intermediate plate and the cover plate.

According to one embodiment, the secondary insulating barrier comprises an anchoring plate, the base of the primary anchoring member being anchored to said anchoring plate. According to one embodiment, the anchor plate is housed in a recess formed in the cover plate of a secondary insulating panel, the anchor plate having an internal surface flush with the internal face of the cover plate.

According to one embodiment, the anchor plate comprises a threaded orifice and the base has a threaded outer end, the base of the primary anchor member being anchored onto the anchor plate by screwing the threaded end of the base into the threaded hole in the anchor plate.

According to one embodiment, an inner end of the rod opposite the base is threaded, and the primary anchoring member further comprises a nut screwed onto said threaded inner end, the support element being interposed between said nut and the base of the primary anchor member.

According to one embodiment, the deformable gasket is inserted between the bearing element and the sealing washer.

According to one embodiment, one or more elastic washers are inserted between the nut and the bearing element.

According to one embodiment, the primary anchoring member has an anchoring shoulder projecting laterally from the rod, said anchoring shoulder forming an anchoring surface developing in a plane perpendicular to the direction of thickness, said anchoring surface being turned towards the support element, the deformable seal being fixed in a leaktight manner on said anchoring surface.

According to one embodiment, the inner end of the deformable seal fixed to the rod is inserted between the mounting portion of the bell and the planar anchoring surface of the anchoring shoulder.

According to one embodiment, the bell has freedom of movement along the thickness direction of the vessel wall. According to one embodiment, the freedom of movement of the bell is limited on the one hand by the nut mounted on the rod, or if necessary the elastic washer(s), and, on the other hand, by the surface of anchor shoulder anchor.

According to one embodiment, the inner axial end of the deformable seal fixed to the rod is interposed between the anchoring surface of the anchoring shoulder and the nut mounted on the rod, or if necessary the spring washers.

According to one embodiment, the secondary sealed membrane and/or the primary sealed membrane is made of an alloy of iron and nickel, for example an alloy whose coefficient of expansion is typically between 1.2.10 ^-6 and 2.10 ^-6 K ^{- 1} . According to one embodiment, the secondary sealed membrane and/or the primary sealed membrane is made of an alloy of iron and manganese, for example whose coefficient of expansion is typically of the order of 7 to 9.10 ^-6 K ^-1 . According to one embodiment, the secondary waterproof membrane and/or the primary waterproof membrane comprises a plurality of strakes with raised edges juxtaposed and welded in pairs by their raised edges.

According to one embodiment, the primary sealed membrane and/or the secondary sealed membrane comprises a plurality of metal plates, preferably rectangular, welded together. According to one embodiment, the primary waterproof membrane and/or the secondary waterproof membrane comprises a first series of parallel undulations extending along a first direction and a second series of parallel undulations extending along a second direction, said first direction and said second direction being secant.

According to one embodiment, a transfer wedge is arranged around the bell in a gap between the bell and the adjacent primary insulating panels, for example between the bell and the bottom plates of said adjacent primary insulating panels. Thanks to these characteristics, a lateral displacement of an insulating panel cooperating with the anchoring member is transmitted via the transfer wedge to the bell, to the rod and then to the support of the rod, for example the secondary insulating barrier, this which makes it possible to take up the lateral force exerted by the primary insulating panel without risk of degradation of the sealed connection between the sealing washer and the sealed membrane.

According to one embodiment, the transfer wedge has a thickness, taken along the thickness direction of the vessel wall, less than the thickness of the bottom plate of the primary insulating panel. Thus, during a lateral displacement of the primary insulating panel, the bottom plate alone is brought into abutment against the transfer wedge ensuring good transmission of the forces between the primary insulating panel and the transfer wedge.

According to one embodiment, the transfer wedge comprises an outer portion and a plate, the outer portion developing around the sealing washer in the direction of thickness of the vessel wall, the plate comprising a central orifice surrounding the bell, the outer portion and the plate forming a housing in which the sealing washer is housed with a clearance, so that the wedge can transmit a lateral force to the bell without interfering with the sealing washer.

According to one embodiment, the transfer wedge further comprises an internal portion developing from the plate and surrounding the bell.

According to one embodiment, the outer portion of the transfer wedge is circular cylindrical. According to one embodiment, said outer portion is coaxial with the stem.

According to one embodiment, the transfer wedge comprises one, preferably several, wings developing radially from the external portion of the transfer wedge and parallel to the direction of thickness of the vessel wall. According to a mode of realization said or said wings are housed between two adjacent primary insulating panels.

According to one embodiment, the transfer spacer is smaller in size than the spacing available between the panels. The assembly of the wedge between the panels is thus facilitated.

According to one embodiment, the sealing washer has a flat and the bell has a flat, said flats being configured to be engaged by a screwing tool making it possible to fasten the stem and the sealing washer in rotation without torsion of the deformable seal during a screwing operation of the anchoring member in its support, for example in the secondary insulating barrier. According to one embodiment, the sealing washer comprises a flat and the stem comprises a flat, said flats being able to be brought into engagement by a screwing tool making it possible to fasten the stem and the sealing washer in rotation without torsion of the joint deformable.

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, the invention also provides a vessel for transporting a cold liquid product comprising a double hull and a tank mentioned above arranged in the double hull.

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.

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.

Brief description of figures

• [fig.1] la figure 1 est une vue partielle écorchée de dessus d'une paroi de cuve étanche et thermiquement isolante dans laquelle la membrane étanche primaire n'est pas illustrée ;
• [fig.2] la figure 2 est une vue en coupe de la paroi de cuve de la figure 1 selon le plan de coupe A-A illustré sur la figure 1 ;
• [fig.3] la figure 3 est une vue de détail de la zone B de la figure 2 illustrant un organe d'ancrage primaire ancrant deux panneaux isolants primaires adjacents ;
• [fig.4] la figure 4 est une vue en perspective schématique de l'organe d'ancrage de la figure 3 ;
• [fig.5] la figure 5 est une vue en perspective schématique de l'organe d'ancrage primaire illustré sur la figure 4 dans lequel la cloche n'est pas illustrée ;
• [fig.6] la figure 6 est une vue en coupe d'un deuxième mode de réalisation de l'organe d'ancrage primaire ;
• [fig.7] la figure 7 est une vue en coupe d'un troisième mode de réalisation de l'organe d'ancrage primaire ;
• [fig.8] la figure 8 est une vue en coupe d'un organe d'ancrage primaire selon un quatrième mode de réalisation ;
• [fig.9] La figure 9 est une représentation schématique écorchée d'une cuve de navire méthanier et d'un terminal de chargement/déchargement de cette cuve ;
• [fig.10] La figure 10 est une vue en perspective schématique d'un organe d'ancrage primaire selon un cinquième mode de réalisation ;
• [fig.11] La figure 11 est une vue en coupe de l'organe d'ancrage primaire de la figure 10 coopérant avec les deux panneaux isolants primaires ;
• [fig.12] La figure 12 est une vue en perspective schématique de l'organe d'ancrage de la figure 11 ;
• [fig.13] La figure 13 est une vue en coupe d'un organe d'ancrage primaire selon un sixième mode de réalisation, l'organe d'ancrage primaire comportant une cale de transfert ;
• [fig.14] La figure 14 est une vue de dessus de l'organe d'ancrage primaire de la figure 13 ;
• [fig.15] La figure 15 est une vue en perspective schématique avec coupe d'une portion de barrière thermiquement isolante secondaire sur laquelle repose une portion de membrane étanche secondaire, la barrière thermiquement isolante secondaire comportant une plaque d'ancrage destinée à recevoir un organe d'ancrage primaire ;
• [fig.16] La figure 16 est une vue en perspective schématique d'une partie d'organe d'ancrage primaire et d'un outil de montage de ladite partie d'organe d'ancrage primaire sur la plaque d'ancrage de la barrière thermiquement isolante secondaire de la figure 15 ;
• [fig.17] La figure 17 est une vue en perspective schématique avec coupe de l'organe d'ancrage primaire de la figure 16 après montage sur la plaque d'ancrage de la barrière thermiquement isolante secondaire et ajout d'une cloche.

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 ] there figure 1 is a partial cutaway top view of a sealed and thermally insulating vessel wall in which the primary sealed membrane is not shown;
• [ fig.2 ] there figure 2 is a sectional view of the vessel wall of the figure 1 according to section plan AA illustrated on the figure 1 ;
• [ fig.3 ] there picture 3 is a detail view of zone B of the figure 2 illustrating a primary anchoring member anchoring two adjacent primary insulating panels;
• [ fig.4 ] there figure 4 is a schematic perspective view of the anchor member of the picture 3 ;
• [ fig.5 ] there figure 5 is a schematic perspective view of the primary anchor shown in the figure 4 in which the bell is not illustrated;
• [ fig.6 ] there figure 6 is a sectional view of a second embodiment of the primary anchor member;
• [ fig.7 ] there figure 7 is a sectional view of a third embodiment of the primary anchor member;
• [ fig.8 ] there figure 8 is a sectional view of a primary anchoring member according to a fourth embodiment;
• [ fig.9 ] There figure 9 is a cutaway diagrammatic representation of an LNG carrier tank and a loading/unloading terminal for this tank;
• [ fig.10 ] There figure 10 is a schematic perspective view of a primary anchor according to a fifth embodiment;
• [ fig.11 ] There figure 11 is a cross-sectional view of the primary anchoring member of the figure 10 cooperating with the two primary insulating panels;
• [ fig.12 ] There figure 12 is a schematic perspective view of the anchor member of the figure 11 ;
• [ fig.13 ] There figure 13 is a sectional view of a primary anchoring member according to a sixth embodiment, the primary anchoring member comprising a transfer wedge;
• [ fig.14 ] There figure 14 is a top view of the primary anchoring member of the figure 13 ;
• [ fig.15 ] There figure 15 is a diagrammatic perspective view with section of a secondary thermally insulating barrier portion on which rests a secondary sealed membrane portion, the secondary thermally insulating barrier comprising an anchoring plate intended to receive a primary anchoring member;
• [ fig.16 ] There figure 16 is a schematic perspective view of a part of the primary anchoring member and of a tool for mounting said part of the primary anchoring member on the anchoring plate of the secondary thermally insulating barrier of the figure 15 ;
• [ fig.17 ] There figure 17 is a schematic cross-sectional perspective view of the primary anchoring member of the figure 16 after assembly on the anchor plate of the secondary thermally insulating barrier and addition of a bell.

Description of embodiments

In the remainder of the description, the terms "external" and "internal" will be used to designate, according to the definitions given in the description, the relative position of one element with respect to another, with reference to the interior of the tank. Thus, an element close to or facing the interior of the tank is qualified as internal as opposed to an external element located close to or facing the outside of the tank. Similarly, the expressions “radially on the periphery” or “radially external” characterize the portion remote from an axis defining a circular element, as opposed to the expression radially internal which characterizes the portion close to said axis. Furthermore, the expression “transverse” is used to qualify a displacement or a direction of development of an element according to a direction situated in a plane perpendicular to the direction of thickness of the vessel wall.

A sealed and thermally insulating tank for storing a liquefied fluid, such as liquefied natural gas (LNG) comprises a plurality of tank walls having a multilayer structure. THE figures 1 and 2 illustrate a portion of such a sealed and thermally insulating vessel wall. On these figures 1 and 2 , the wall of the tank comprises successively, in the direction of the thickness, from the outside towards the inside of the tank, a secondary thermally insulating barrier, hereinafter secondary insulating barrier 1, retained on a load-bearing wall (not illustrated), a secondary waterproof membrane 2 resting against the secondary insulating barrier 1, a primary thermally insulating barrier, hereinafter primary insulating barrier 3, resting against the secondary waterproof membrane 2 and a primary waterproof membrane 4 intended to be in contact with the gas natural liquid contained in the tank. The load-bearing structure can in particular be formed by the hull or the double hull of a ship. The load-bearing structure comprises a plurality of load-bearing walls defining the general shape of the tank, usually a polyhedral shape, each tank wall being anchored to a respective load-bearing wall.

The secondary insulating barrier 1 comprises a plurality of secondary insulating panels 5 which are anchored to the load-bearing wall by means of secondary anchoring members (not shown). The secondary insulating panels 5 have a generally parallelepipedal shape and are arranged in parallel rows. Mastic sausages (not shown) are interposed between the secondary insulating panels 5 and the load-bearing wall to compensate for the deviations of the load-bearing wall with respect to a flat reference surface. A kraft paper can be inserted between the rolls of mastic and the load-bearing wall to prevent adhesion of the rolls of mastic to the load-bearing wall. Alternatively, the mastic beads are directly in contact with the load-bearing wall and thus ensures fixing of the secondary insulating panels 5 by adhesion to the load-bearing wall.

The structure of a secondary insulating panel 5 illustrated in the figure 2 comprises a bottom plate 7, a cover plate 8 and an insulating gasket 9 interposed between the bottom plate 7 and the cover plate 8. The bottom plates 7 and cover 8 are for example made of plywood. The insulating gasket 9 is for example a layer of insulating polymer foam sandwiched between the bottom plate 7 and the cover plate 8. The insulating gasket 9 is glued to the bottom plate 7 and the cover plate 8. The foam insulating polymer may in particular be a polyurethane-based foam, optionally reinforced with fibers.

The secondary insulating panels 5 have recesses to receive the secondary anchoring members. Such recesses are for example made in the insulating gasket 9 and in the cover plate 8 so as to uncover a corner portion of the bottom plate 7. The secondary anchoring members comprise a base anchored to the load-bearing wall and a rod developing in the thickness direction of the vessel wall. The base is for example hollow and has an orifice through which the rod passes, a nut being screwed onto the end of the rod housed in the hollow base to hold the rod anchored to the base and therefore to the load-bearing wall. The secondary anchoring members in another embodiment may take the form of a rod welded to the inner shell.

In one embodiment, the recess is placed in the corner areas. The corner portion of the bottom plate 7 has a cutout to allow the passage of the stem of the secondary anchoring device. A secondary support plate is engaged on the rod and held on the rod by a nut screwed on an internal end of the rod opposite the base. This secondary support plate rests on the bottom plate corner portions 7 of adjacent secondary insulating panels 5, for example four adjacent secondary insulating panels 5, in order to anchor said secondary insulating panels 5 to the load-bearing wall. In a variant, the support of the secondary support plate on the secondary insulating panels 5 can be done by means of a cleat supported on the corner portion of the bottom plate 7.

In another variant, the recess is placed on two side faces of the secondary insulating panels 5 and the secondary anchoring members are placed in these recesses between two adjacent secondary insulating panels 5 in the width or length direction of said secondary insulating panels. 5.

The cover plate 8 has on an internal face, that is to say on a face opposite to the insulating gasket 9, grooves to receive welding supports 6.

The structure of the secondary insulating panels 5 and of the secondary anchoring member are described above by way of example. Also, in another embodiment, the secondary insulating panels 5 are likely to have another general structure, for example that described in the document WO2012/127141 . The secondary insulating panels 7 are then made in the form of a box comprising a bottom plate, a cover plate and supporting webs extending, in the direction of thickness of the vessel wall, between the bottom plate and the plate. lid and delimiting a plurality of compartments filled with an insulating filling, such as perlite, glass or rock wool.

In another embodiment, the secondary insulating panels comprise a bottom plate, a cover plate and an intermediate plate interposed between the bottom plate and the cover plate. The insulating gasket then comprises a first layer of insulating gasket interposed between the bottom plate and the intermediate plate and a second layer of insulating gasket interposed between the intermediate plate and the cover plate. The first layer of insulating lining is for example glued to the bottom plate and to the intermediate plate. The second layer of insulating lining is for example glued to the intermediate plate and to the cover plate. In this embodiment, the recess can be made in the cover plate and the second layer of insulating lining only, the secondary bearing plate resting on an uncovered portion of the intermediate plate. In addition, the cutout allowing the passage of the rod is made in the plate intermediate, the first layer of insulating gasket and the bottom plate. Such a secondary insulating panel is for example described in the document WO2014/096600 .

In one embodiment, the secondary insulating panels are glued to the load-bearing wall, for example by means of the aforementioned mastic beads. In this case, it is possible to eliminate the secondary anchoring members and the recesses which receive them.

Coming back to the figure 1 , it is observed that the secondary waterproof membrane 4 comprises a continuous layer of strakes 10, metallic, with raised edges. The strakes 10 are welded by their raised edges to parallel welding supports 6 which are fixed in the grooves provided on the cover plates 8 of the secondary insulating panels 5. The strakes 10 are, for example, made of ^Invar® : it that is to say an alloy of iron and nickel whose coefficient of expansion is typically between 1.2.10 ^-6 and 2.10 ^-6 K ^-1 . It is also possible to use alloys of iron and manganese whose coefficient of expansion is typically of the order of 7 to 9.10 ^-6 K ^-1 .

The primary thermally insulating barrier 5 comprises a plurality of primary insulating panels 11 which are anchored to the load-bearing wall by means of primary anchoring members 12 described in more detail below. The primary insulating panels 11 have a generally parallelepipedal shape and are juxtaposed to form the primary insulating barrier 3. In addition, they may have width, length or thickness dimensions identical to or different from those of the secondary insulating panels 5. In particular, their thickness in the thickness direction of the vessel wall is likely to be lower than that of the secondary insulating panels 5. Each of the primary insulating panels 11 is positioned offset from the secondary insulating panels 5 on which it rests. . Thus, the adjacent corners of the primary insulating panels 11 are grouped together in line with the cover plate 8 of a secondary insulating panel 5 on which said primary insulating panels 11 rest.

The primary insulating panels 11 may have a multilayer structure analogous to the structure of the secondary insulating panels 5. Thus, in the example shown, the primary insulating panels 11 successively comprise, along the thickness direction of the vessel wall, a bottom plate 13, for example in plywood, a primary insulating gasket 14 and a cover plate 15, for example in plywood. The primary insulating lining is for example a layer of insulating polymer foam, for example a foam based on polyurethane, optionally reinforced with fibers. The insulating gasket 14 is preferably glued to the bottom plate 13 and to the cover plate 15.

A primary insulating panel 11 has recesses at its corner areas so that the bottom plate 13 projects beyond the primary insulating gasket 14 and the cover plate 15. Thus, the bottom plate 13 forms at the level of the corner zones of the primary insulating panel 11 a bearing zone intended to cooperate with a primary bearing plate 16 of the primary anchoring member 12. In the embodiment illustrated in the picture 3 , a wedge 17 is added to the bottom plate 13, said wedge 17 having a shape similar to that of the bearing zone and cooperating with the primary bearing plate 16 to anchor the primary insulating panel 11.

The bottom plate 13 of the primary insulating panel 11 includes grooves 18 intended to receive the raised edges of the strakes 10 of the secondary waterproof membrane 2. The cover plate 15 includes anchoring strips 19, illustrated on the figure 1 , to anchor the primary waterproof membrane 4. These anchoring strips 19 are housed in counterbores formed on the internal face of the cover plate 15. The primary insulating panel 11 may further comprise relaxation slots 20 formed in the plate cover 15 and in an internal portion of the primary insulating gasket 14. Such relaxation slots 20 have the function of preventing deformation or degradation of the primary insulating panel 11 due to the differential contractions between the cover plate 15 and the primary insulating gasket 14. Such relaxation slots 20 also make it possible to let corrugations 21 work and thus avoid creating stresses in the primary waterproof membrane 4 and in the primary insulating barrier 4 in the case of a primary waterproof membrane 4 comprising undulations 21 as described below.

The structure of the primary insulating panel 11 is described above by way of example. Also, in another embodiment, the primary insulating panels 11 are likely to have another general structure, for example that described in the document WO2012/127141 .

In another embodiment, the primary insulating barrier 3 comprises primary insulating panels having at least two different types of structure, for example the two aforementioned structures, depending on their location in the tank.

The primary waterproof membrane 4 comprises a continuous layer of rectangular sheets which have two series of mutually perpendicular undulations 21. The rectangular sheets are welded together by forming small areas of overlap along their edges, according to the known technique. A rectangular sheet preferably has dimensions of width and length which are multiples integers of a spacing between corrugations and also integer multiples of the dimensions of the primary insulating panels 11.

A primary anchoring member 12 is described below with regard to the figures 3 to 5 . There picture 3 shows a detail view of the primary anchoring member 12 illustrated in the figure 2 to reference B. Furthermore, on the figures 4 and 5 , nut 32 and bearing plate 16 are omitted. On these figures 3 to 5 , a single primary anchoring member 12 is illustrated and the description below for this anchoring member applies analogously to one, several or all of the primary anchoring members 12 integrated into the sealed tank and thermally insulating.

As explained above, in the embodiment illustrated in the figures 1 to 5 , the primary insulating panels 11 are anchored to the load-bearing wall via the secondary insulating panels 5. For this, the cover plate 8 of the secondary insulating panel 5 comprises an anchoring plate 22. This anchoring plate 22 is housed in a recess 23 made in the cover plate 8.

The recess 23 has an inner section 24 having a first diameter and an outer section 25 having a second diameter. The second diameter is greater than the first diameter so that the outer section 25 of the recess 23 forms lateral recesses interposed between a portion of the cover plate 8 surrounding the inner section 24 and the insulating gasket 9.

The anchor plate 22 has a shape complementary to the recess 23. An internal face 26 of the anchor plate 22 is flush with an internal face 27 of the cover plate 8 of the secondary insulating panel 5. Thus, the plate of anchor 22 forms with cover plate 8 a substantially continuous planar surface on which rests secondary waterproof membrane 2. Furthermore, an outer section 28 of anchor plate 22 is housed in outer section 25 of recess 23 and is thus interposed between the cover plate 8 and the insulating trim 9. The anchoring plate 22 is preferably glued to the insulating trim 9 of the secondary insulating panel. The anchoring plate 22 is thus locked in movement along the thickness direction of the vessel wall. This anchor plate 22 further comprises a central threaded housing 29.

The primary anchor 12 comprises a base 30, a rod 31, the primary bearing plate 16 and a nut 32.

The base 30 has an external thread and is screwed into the central housing 29 of the anchor plate 22. In other words, the base 30 of the primary anchor member 12 is anchored in the anchor plate 22.

The stem 31 develops from the base 30 along the thickness direction of the vessel wall towards the inside of the vessel. The rod 31 passes through an orifice made in the secondary waterproof membrane 2. As illustrated in the figures 1 to 3 , this rod 31 develops in the space separating the corners of two primary insulating panels 11.

The primary support plate 16 has a central passage 60. This primary support plate 16 is engaged on the rod 31. The primary support plate 16 is supported on the wedges 17 arranged on the projecting portions of the bottom plates 13 of the primary insulating panels 11 with which the primary anchoring member 12 cooperates. Furthermore, the internal end of the rod 31 opposite the base 30 is threaded and the nut 32 is screwed onto this internal end of the rod 31 in order to press the primary bearing plate 16 on the wedges 17. In the embodiment illustrated in the picture 3 , spring washers 33, for example of the Belleville washer type, are interposed between the primary bearing plate 16 and the nut 32.

In order to ensure the sealing of the secondary sealed membrane 2 at the level of the orifice of said secondary sealed membrane 2 through which the rod 31 passes, the primary anchoring member 12 further comprises a sealing washer 34.

This sealing washer 34 comprises an annular body 35 having a central orifice 36. The sealing washer 34 further comprises a collar 37 developing radially outwards from an outer portion of the radially outer face of the annular body 35. Furthermore, an internal face 38 of the annular body 35 comprises a rib 39 projecting in the direction of thickness of the vessel wall. This rib 39 develops from a radially inner portion of said inner face 38. The flange 37 is for example formed by a peripheral portion of the annular body 35.

The sealing washer 34 is engaged on the rod 31, the rod 31 passing through the central hole 36 of the sealing washer 34. The sealing washer 34 is inserted between the secondary sealed membrane 2 and the support plate primary 16. The central orifice 36 of the sealing washer 34 has a diameter greater than the diameter of the rod portion 31 passing through said central orifice 36. Thus, a transverse clearance, that is to say in a direction perpendicular to the thickness direction of the vessel wall, separates a radially inner face delimiting the central orifice 36 of the annular body 35 and the rod 31. This play allows the sealing washer 34 to be movable transversely with respect to the rod 31, and therefore relative to the primary bearing plate 16.

In an embodiment not illustrated, the central orifice is not circular and has a dimension in at least one transverse direction greater than the dimension of the rod 31 in said at least one transverse direction. In such an embodiment, a play along said at least one transverse direction therefore separates the central orifice 36 from the rod in order to allow movement of the sealing washer relative to the rod 31 along said at least one transverse direction.

The collar 37 is fixed in a leaktight manner to the secondary leaktight membrane 2 around the orifice of said secondary leaktight membrane 2. This leaktight fixing is for example produced by welding.

The primary anchoring member 12 comprises an anchoring shoulder 40 projecting radially outwards from the rod 31. This anchoring shoulder 40 is inserted between the sealing washer 34 and the primary bearing plate 16 The anchoring shoulder 40 has a planar anchoring surface 41 developing in a plane perpendicular to the direction of thickness of the vessel wall. This anchoring surface 41 faces the inside of the tank.

The primary anchoring member 12 comprises a deformable joint sealingly connecting the rod 31 and the sealing washer 34. This deformable joint comprises a bellows 42. An internal axial end of this bellows 42 is fixed in a sealing manner on the rod 31. An outer axial end of this bellows 42 is fixed in a sealed manner to the sealing washer 34. More particularly, the inner axial end of the bellows 42 is anchored in a sealed manner to the anchoring surface 41 of the anchoring shoulder 40. The outer axial end of the bellows 42 is anchored in leaktight manner to the rib 39 projecting from the inner face 38 of the annular body 35. The inner axial end of the bellows 42 is for example welded to the rod 31. The outer axial end of the bellows 42 is for example welded to the sealing washer 34.

This bellows 42 has deformable folds 61, three in number in the embodiment illustrated in the picture 3 . In a manner not shown, the number of folds 61 of the bellows 42 is not limited to three and may be greater given the spacing between the shoulder 40 and the surface 38 of the flange 37. Thus, the bellows 42 may have between three and thirty-two plies 61, ideally from six plies 61 to twenty-four plies 61 depending on said spacing, said spacing being for example between 20 and 45mm. The bellows 42 is substantially cylindrical. The folds 61 forming the bellows 42 have identical dimensions. Such a bellows 42 is for example made of stainless steel. In order to ensure the flexibility of said bellows 42, it has a small thickness, preferably less than 1 mm, for example between 0.1 and 0.5 mm and more particularly between 0.1 mm and 0.3 mm in thickness.

This bellows 42 provides a flexible, deformable and tight connection between the rod 31 and the sealing washer 34. This flexible and deformable connection associated with the play between the sealing washer 34 and rod 31 allows the relative displacement in a sealed manner between the sealing washer 34 and the rod 31. Thus, the sealing washer 34 being fixed in a sealing manner on the secondary sealed membrane 2 and the rod 31 carrying the primary bearing plate 16 resting on the primary insulating panels 11, relative movement is possible between the secondary waterproof membrane 2 and the secondary insulating panels 5 and/or the primary insulating panels 11 without risk of degradation of the waterproof membrane secondary 2 or loss of sealing of the secondary waterproof membrane 2. In particular, when the rod 31 is fixed to a secondary insulating panel, deformation and/or displacement of said secondary insulating panel 5 is possible without this deformation and/or or this movement generates stress on the secondary waterproof membrane 2 or on the connection between the sealing washer 34 and the secondary waterproof membrane 2.

Such a relative displacement between the secondary insulating panels 5 and/or the primary insulating panels 11 and the secondary waterproof membrane 2 can occur due to differential contractions, deformation of the secondary insulating barrier 1 and/or of the load-bearing wall, or even due to stresses on the primary insulating panels 11 related to the movement of liquid in the tank.

In order on the one hand to protect the bellows 42, for example during the construction of the tank and the assembly of the primary anchoring member 12, said primary anchoring member comprises a bell 43. This bell 43 comprises a portion assembly 44 and a protective portion 45. This bell 43 can be combined with the different types of bellows 42 described above and below.

The mounting portion 44 is flat in shape and has a central hole. The bell 43 is mounted on the rod 31 of the primary anchoring member 12, said rod passing through the central orifice of the mounting portion 44. The mounting portion is inserted between the anchoring shoulder 40 and the plate primary bearing plate 16. The bell is thus blocked from moving along the thickness direction of the vessel wall by the primary bearing plate 16 on the one hand and by the anchoring surface 41 on the other hand.

The protective portion 45 is hollow and has an inner end adjoining a peripheral edge of the mounting portion 44. The protective portion 45 develops from its inner end along the bellows 42 in the direction of the sealing washer 34 , the bellows 42 being housed in said hollow protection portion 45 . The protective portion 45 is also flared so that an outer end of said protective portion 45 is arranged in line with the flange 37 of the sealing washer 34. Thus, the bell 43 completely surrounds the bellows 42, since the inner end of said bellows 42 on the anchoring surface 41 to the outer end of said bellows 42 fixed on the rib 39.

The outer end of the protective portion 45 has a rim 46 developing in a plane perpendicular to the direction of thickness of the vessel wall. This rim 46 forms an abutment surface 47 located opposite the flange 37. Such abutment surface 47 blocks the movement of the flange 37, and therefore of the sealing washer 34, in the direction of the inside the tank, the bell 42 itself being blocked by the abutment of its mounting portion 44 on the primary bearing plate 16.

Thus, the collar 37 being fixed in a sealed manner to the secondary sealed membrane 2, during deformation of the bearing wall or in the presence of an overpressure in the secondary sealed membrane 2, the local deformation of the secondary sealed membrane 2 at the level of the primary anchoring member 12 is blocked by the abutment of the flange 37 of the sealing washer 34 on the abutment surface 47. In another embodiment, the mounting portion 44 of the bell 43 is fixed on the rod, for example by welding.

In an embodiment not shown, the primary insulating panels 11 and the secondary insulating panels 5 have identical dimensions and are arranged so that the corners of the secondary insulating panels 5 are aligned along the thickness direction of the vessel wall with the corners of the primary insulating panels 11. In such an embodiment, the primary anchoring member 12 is not anchored in a secondary insulating panel 5 but directly on the secondary anchoring member. Such a configuration is for example described in the document WO2014096600 which has a joint anchoring device for the secondary insulating panels 5 and the primary insulating panels 11, the base 30 of the primary anchoring member 12 being fixed to one end of the secondary anchoring member. Thus, in this embodiment, a primary anchoring member as described above, the base 30 of the primary anchoring member 12 is not anchored in the anchoring plate 22 housed in a plate of cover 8 of a secondary insulating panel 5 but in a base fixed to the inner end of the secondary anchoring member.

There figure 6 illustrates a primary anchor member 12 according to a second embodiment. Items that are identical or fulfill the same function as items described above with regard to the figures 1 to 5 have the same reference.

This second embodiment differs from the embodiment illustrated in the figures 1 to 5 in that the annular body of the sealing washer has a face radially external bevelled, that is to say inclined with respect to the thickness direction of the vessel wall.

There figure 7 illustrates a primary anchor 12 according to a third embodiment. Items that are identical or fulfill the same function as items described above with regard to the figures 1 to 5 have the same reference.

This third embodiment differs from the embodiment illustrated in the figures 1 to 5 in that the bellows 42 is flared. Thus, the folds 61 forming said bellows 42 have increasing dimensions from the internal axial end of the bellows 42 anchored on the anchoring surface 42 towards the external axial end of the bellows 42 anchored on the sealing washer 34.

Furthermore, in this third embodiment the inner face 38 of the annular body 35 of the sealing washer 34 does not have the rib 39, said inner face 38 being flat. In this third embodiment, the external axial end of the bellows 42 is fixed directly to the internal surface 38 which is flat. In particular, the bellows 42 having a flared shape, the outer axial end of said bellows 42 is fixed on a radially outer peripheral edge of said inner surface 38.

This third embodiment also differs from the embodiment described with regard to the figures 1 to 5 in that the primary anchoring member 12 does not include a bell 43. Such a bell 43 could, however, be added.

In this third embodiment, the rod 31 has a shoulder 48 projecting laterally. This shoulder 48 is inserted between the anchoring shoulder 40 and the sealing washer 34. In addition, this shoulder 48 has at least one transverse dimension greater than the dimension of the central orifice of the sealing washer 34. Thus, this shoulder 48 has an outer face 49 facing the inner surface 38 of the annular body 35 of the sealing washer 34. In other words, a peripheral portion of this outer face 49 forms the abutment surface 47 This shoulder 48 thus fulfills the function of abutment of the sealing washer 35 blocking the movement towards the interior of the tank of the said sealing washer 34 and preventing the local deformation of the secondary sealed membrane 2.

There figure 8 illustrates a primary anchor 12 according to a fourth embodiment. Items that are identical or fulfill the same function as items described above with regard to the figures 1 to 5 have the same reference.

In this fourth embodiment, the primary anchoring plate 16 is replaced by an anchoring cross 54. This anchoring cross 54 has a mounting portion 55 and a plurality of support legs 56, for example four support legs 56 as illustrated in the figure 7 And 8 of the document WO2014/057221 .

The assembly portion 55 of the anchoring cross 54 is flat and develops in a plane perpendicular to the direction of thickness of the vessel wall. This assembly portion 55 has a central hole through which the rod 31 passes so that the anchoring cross 54 is mounted on the rod 31.

Each bearing lug 56 has an internal end contiguous with a peripheral edge of the mounting portion 55. Each bearing lug 56 develops from the mounting portion 55 in the direction of a bearing surface 57 formed by the protruding portion of the bottom plate 13 of a primary insulating panel 11. An outer end of the support lug 56 has a flange 58 developing in a plane perpendicular to the direction of thickness of the vessel wall. This rim 58 rests on the bearing surface 57 so as to retain the primary insulating panel 11 on the secondary waterproof membrane 2.

Such an anchoring cross 54 provides some protection for the bellows 42 in a similar way to the protection bell 43 described above with regard to the figures 1 to 5 .

In this fourth embodiment, the inner end of the bellows 42 is anchored on a side face 59 of the anchoring shoulder 40, for example in a countersink provided for this purpose in the outer portion of said side face 58.

THE figures 10 to 12 represent a primary anchoring member 12 according to a fifth embodiment. In these figures, the elements which are identical or fulfill the same function as the elements described above with regard to the figures 1 to 5 have the same reference.

In this fifth embodiment, the protective portion 45 of the bell 43 is cylindrical and has a generatrix parallel to the direction of thickness of the vessel wall. The outer end of the protective portion 45 of the bell 43 is arranged in line with the inner face 38 of the annular body 35. In other words, the abutment surface 47 formed by the rim 46 of the outer end of the portion of protection 45 cooperates with the inner face 38 of the annular body 35 to block the movement of the sealing washer 34 towards the inside of the tank. The flange 37 projects radially outwards from the annular body 35 beyond the flange 46. Furthermore, the internal axial end of the bellows 42 is anchored in a sealed manner, for example by welding, on an external face of the anchoring shoulder 40, that is to say on a face of the anchoring shoulder 40 facing the sealing washer 34.

When Liquefied Natural Gas (LNG) is stored in the tank, the movements of said LNG inside the tank, for example linked to the movements of a ship in which said tank is installed, can generate lateral stresses on the panels primary insulators 11. Typically, a movement of LNG in the tank can exert a lateral stress on the undulations 21 of the primary waterproof membrane 4. This lateral stress at the level of said undulation 21 is transmitted to the primary insulating panel 11 on which the primary sealed membrane 4. Under the effect of this stress, the primary insulating panel 11 tends to move laterally, that is to say in a plane perpendicular to the direction of thickness of the vessel wall, and therefore to exert a constraint on the primary anchoring member 12.

The flange 37 protruding radially outwards from the annular body 35 beyond the rim 46 of the bell 43, the bottom plate 13 of the primary insulating panel 11 can be brought into abutment against the flange 37 during the movement of said insulating panel primary 11. Such abutment of the bottom plate 13 on the collar 37 generates a significant stress at the level of the sealed connection between the collar 37 and the secondary sealed membrane 2, this stress possibly jeopardizing the integrity of the sealed membrane secondary 2.

In order to prevent the forces caused by a lateral displacement of the primary insulating panel 11 from being taken up by the sealing washer 34, this fifth embodiment comprises a transfer wedge 62. The transfer wedge 62 makes it possible to transfer the transverse force towards the rod 31 and its support, for example the secondary insulating barrier. In addition, the transverse dimension of the wedge is less than the spacing between the neighboring primary insulating panels to provide sufficient assembly tolerance and to transmit the forces of a primary insulating panel to the rod 31.

This transfer wedge 62 here comprises a base 63, an envelope 64 and wings 65.

The base 63 has a flat shape developing perpendicularly to the thickness direction of the vessel wall. This base 63 is circular in shape, the center of which is coaxial with the rod 31. The base 63 has a central orifice 66. This central orifice 66 is circular and coaxial with the rod 31. The dimensions of the central orifice 66 are greater than the dimensions of the flange 37 so that a space separates the base 63 from the flange 37.

The base 63 rests on the secondary sealing membrane 2 around the collar 37. The bottom plates 13 of the primary insulating panels 11 cooperating with the primary anchoring member 12 may have an external counterbore 67 to house the base 63.

The envelope 64 comprises an outer skirt 68 and an inner skirt 69 connected by a central plate 82.

The outer skirt 68 has a circular cylindrical wall whose generatrix is parallel to the direction of thickness of the vessel wall. This external skirt 68 develops from the internal periphery of the base 63, that is to say from the edge of the central orifice 66 of the base 63. The external skirt 68 develops towards the inside of the tank on a thickness, along the direction of thickness of the vessel wall, greater than or equal to the thickness, taken along said direction of thickness of the vessel wall, of the annular body 35. Thus, an inner end of the outer skirt 68 is radially in line with the protective portion 45 of the bell 43.

The central plate 82 develops in a plane perpendicular to the direction of thickness of the vessel wall. This central plate 82 develops radially inwards from the internal end of the external skirt 68. The central plate 82 comprises a central orifice 83 whose internal diameter is slightly greater than the external diameter of the protective portion 45 of the bell . Thus, the central plate 82 surrounds the protective portion 45 of the bell 43.

The inner skirt 69 has a circular cylindrical wall whose generatrix is parallel to the direction of thickness of the vessel wall. This internal skirt 69 develops from the internal periphery of the central plate 82, that is to say from the edge of the central plate 82 delimiting the central orifice 83. The internal skirt 69 develops towards the inside of the tank on a thickness less than the thickness of the protective portion 45 of the bell 43. Thus, the internal skirt 69 surrounds the protective portion 45 of the bell 43 over only part of the thickness of said protective portion 45.

Typically, the envelope 64 surrounds the flange 37 and forms a housing, visible on the figure 11 And 12 , in which the collar 37 is housed with a clearance, ensuring the protection of said collar 37.

Thus, when a primary insulating panel 11 undergoes a stress causing the lateral displacement of said primary insulating panel 11, the bottom plate 13 of said primary insulating panel 11 abuts against the transfer wedge 62, typically against the base 63 and/or against the external skirt 68. The transfer wedge 62 surrounding the bell 43 and the distance separating the transfer wedge 62 from the bell 43 being less than the distance separating the transfer wedge 62 from the collar 37, the transfer wedge 62 abuts against the bell 43 without generating significant stress on the collar 37. In other words, the path of the forces associated with this lateral displacement of the primary insulating panel 11 passes through the bottom plate 13 of the primary insulating panel 11 which exerts a force on the transfer wedge 62, said transfer wedge then exerting a force on the bell 43 and the rod 31. Thus, the transfer wedge 62 ensures that the path of the forces linked to a lateral displacement of a primary insulating panel 11 does not pass through the collar 37, thus limiting the stresses at the level of the sealed connection between the flange 37 and the secondary sealed membrane 2.

In the embodiment illustrated in the figures 10 to 12 , the transfer wedge 62 further comprises four wings 65 facilitating the positioning of the transfer wedge 62 relative to the primary insulating panels 11 adjacent. These positioning wings 65 are regularly distributed circumferentially around the casing 64. These wings 65 develop radially from the casing 64 parallel to the thickness direction of the vessel wall. Each of said wings 65 is housed between two primary insulating panels 11 cooperating with the primary anchoring member 12. These wings 65 separate compartments offering independent wedges to each of the primary insulating panels 11.

In an embodiment not illustrated, the outer skirt 68 develops in the direction of the interior of the tank beyond the bottom plate 13 of the primary insulating panels 11. Thus, during a lateral displacement of a panel primary insulator 11, the insulating lining 14 is also brought into abutment against the outer skirt 68 in order to transfer the forces associated with the lateral displacement of the primary insulating panel 11 towards the transfer wedge 62.

THE figure 13 And 14 illustrate a primary anchor 12 according to a sixth embodiment.

This sixth embodiment differs from the fifth embodiment illustrated with regard to the figures 10 to 12 in that the outer end of the protective portion 45 of the bell 43 is arranged in line with the flange 37. In addition, the rim 46 of the outer end of the protective portion 45 projects radially beyond the flange 37. Thus, the abutment surface 47 formed by the rim 46 of the outer end of the protective portion 45 cooperates with the internal face of the flange 37 to block the movement of the sealing washer 34 in the direction of the inside of the tank.

In this embodiment, the transfer wedge 62 is formed by a block 84. This block 84 has a central orifice. This central orifice has an internal diameter slightly greater than the external diameter of the protective portion 45 of the bell 43 so that the block 84 surrounds the protective portion 45 of the bell 43.

The block 84 has a thickness, taken along the thickness direction of the vessel wall, less than the thickness of the bottom plate 13 of the adjacent primary insulating panels 11 so that an internal face of the block 84 is arranged at the outside, in the direction of thickness of the vessel wall, of the internal face of the bottom plates 13. Furthermore, in the embodiment illustrated in the figure 13 , the block 84 rests on an internal face of the rim 46 of the protective portion 45 of the bell 43.

A peripheral side face of the block 84 is of generally complementary shape to the recesses made in the bottom plates 13 of the primary insulating panels 11 cooperating with the primary anchoring member 12. In other words, the distance separating the bottom plates 13 from the panels primary insulators 11 and block 84 substantially corresponds to an assembly clearance. Thus, a lateral displacement of a primary insulating panel 11 generates almost from the start of said displacement a support on the peripheral side face of block 84.

Thus, during a lateral displacement of a primary insulating panel 11, the bottom plate 13 of said primary insulating panel 11 abuts against the transfer wedge 62, and more particularly on the peripheral side face of the block 84, and the wedge of transfer abuts against the bell 43 and the rod 31 without substantially exerting stress on the collar 37. The stress exerted by the primary insulating panel 11 on the transfer wedge 62 is therefore transmitted to the rod 31 without substantially passing through the connection between the flange 37 and the secondary waterproof membrane 2.

An example of a method for mounting a primary anchoring member is described below with regard to the figures 15 to 17 . On these figures 15 to 17 and in the description below, elements which are identical or perform the same function as elements already described above bear the same reference.

Analogously to the description above with regard to the figures 1 to 5 , the anchor plate 22 is housed in a recess 23 made in the cover plate 8 of a secondary insulating panel 5. The inner face 26 of the anchor plate 22 is flush with an inner face 27 of the cover plate 8 of the secondary insulating panel 5. The anchoring plate 22 further comprises a central threaded housing 29 intended to receive the base 30 of the primary anchoring member 12.

Preferably, the primary anchor member 12 is at least partially prefabricated. A prefabricated portion of the primary anchor member 12 comprises for example, as illustrated in the figure 16 , the base 30, the rod 31, the bellows 42, the internal axial end of which is fixed to the anchoring shoulder 40, and the sealing washer 34 to which the external axial end of the bellows is fixed.

However, with a primary anchoring member 12 thus prefabricated, the sealing washer 34 is integral in rotation with the rod 31 via the bellows 42. Thus, when the rod 31 is turned to screw the base 30 into the central housing 29 threaded, the sealing washer 34 is also turned. However, this rotation of the sealing washer 34 can generate friction between the outer face of said sealing washer 34 and the secondary sealed membrane 3, in particular at the end of the screwing of the base 30 into the housing 29. Such friction generates a torsion in the bellows 42 which is likely to degrade said bellows 42 and therefore the tightness of said bellows 42.

In order to avoid twisting in the bellows 42 when the base 30 is screwed into the housing 29, the body 35 of the sealing washer 34 has flats 85 on its lateral face connecting the collar 37 and the internal face 38 of the body 35. Similarly, the anchoring shoulder 40 also includes flats 86. The flats 85 of the sealing washer 34 and the flats 86 of the anchoring shoulder 40 preferably develop in the same planes.

The method for mounting the primary anchoring member 12 provides for the use of a hollow key 87 comprising internal faces 88 complementary to the flats 85 and 86. Furthermore, the hollow portion of the key 87 preferably has a height greater than the height of the rod 31 and at least greater than or also the distance between the internal axial end of the rod and the flat 85 carried by the sealing washer 34. Thus, due to the complementarity between the internal faces 88 of the key and the flats 85 and 86, a rotation of the key 87 results in a rotation of both the rod 31, and therefore of the base 30, and of the sealing washer 34. On the figure 16 , the anchoring shoulder 40 and the body 35 comprise six flats 85 and 86, however the number and dimensions of these flats may be different, the primary anchoring member 12 possibly comprising one, two or more flats 85 and 86 complementary to the internal faces 88 of the key 87 so that the sealing washer 34 and the anchoring shoulder, and therefore the rod 31 and the base 30, are connected in rotation when using the key 87 .

In order to mount the prefabricated portion of the primary anchor member 12 on the anchor plate 22, said prefabricated portion is inserted into the hollow portion of the key 87. The key 87 is then turned in order to screw the base 30 into the housing 29. The sealing washer 34 being turned with the rod 31, the friction between the sealing washer 34 and the secondary sealed membrane 3 does not cause the bellows 42 to twist.

When the base 30 is completely screwed into the housing 29, the bell 43 can be attached to the rod 31 as illustrated in the figure 17 . Alternatively, the portion prefabricated of the anchoring member can also include the bell 43 which is then fixed, for example by welding, on the rod 31.

In this alternative illustrated on the figure 17 , the bell 43 has a flat 89 similar to the flat 86 of the anchoring shoulder 40. Furthermore, the sealing washer 34, and more particularly the flat 85, is arranged radially beyond the rim 46 of the bell 43. Thus, the internal faces 88 of the key 87 cooperate with the flat of the bell 43 and the flat of the sealing washer 34 to allow the base 30 to be screwed into the housing 29 while driving the washer in rotation. sealing 34 so as not to generate torsion in the bellows 42.

The technique described above for producing a leaktight and thermally insulating tank can be used in different types of tanks, for example to form an LNG tank in an onshore installation or in a floating structure such as an LNG carrier or other.

With reference to the 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.

There figure 9 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an installation on land 77. The loading and unloading station 75 is a fixed offshore installation comprising a mobile 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 pipe submarine 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the land installation 77 over a long 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 (19)

1. [A sealed and thermally insulating tank comprising a tank wall, the tank wall comprising, successively from the exterior of the tank to the interior of the tank in a thickness direction of the tank wall, a secondary insulating barrier (1) intended to be anchored on a support wall, a secondary sealed membrane (2) resting on the secondary insulating barrier (1), a primary insulating barrier (3) resting on the secondary sealed membrane (2) and a primary sealed membrane (4) resting on the primary insulating barrier (3) and intended to be in contact with a product contained inside the tank,

   the primary insulating barrier (3) comprising a plurality of juxtaposed primary insulating panels (11),

   the tank further comprising a plurality of primary anchoring members (12) intended to be retained, directly or indirectly, on the support wall, each of said primary anchoring members (12) interacting with at least one primary insulating panel (11) of the plurality of primary insulating panels (11) in such a way as to retain said at least one primary insulating panel (11) on the secondary sealed membrane (2),

   in which a said primary anchoring member (12) comprises:

   - a base (30) intended to be retained, directly or indirectly, on the support wall,

   - a stem (31) extending in the thickness direction of the tank wall from said base (30) toward the primary sealed membrane (4), said stem (31) passing through an opening in the secondary sealed membrane (2),

   - a bearing element (16, 54) mounted on the stem (31), said bearing element (16, 54) bearing on a primary insulating panel (11) in such a way as to retain said primary insulating panel (11) on the secondary sealed membrane (2),

   - a sealing washer (34) engaged on the stem (31) between the bearing element (16) and the opening in the secondary sealed membrane (2), the sealing washer (34) having a central opening (36) through which the stem (31) passes, the sealing washer (34) being secured sealingly to the secondary sealed membrane (2) around the opening in said secondary sealed membrane (2),
   characterized by the fact that said primary anchoring members (12) includes

   - a deformable seal (42) sealingly connecting said sealing washer (34) and the stem (31) in such a way as to allow a relative movement between the sealing washer (34) and the stem (31).
2. The sealed and thermally insulating tank as claimed in claim 1, in which the central opening (36) in the sealing washer (34) has a transverse dimension greater than the transverse dimension of a portion of stem (31) engaged in said central opening (36), in such a way as to allow the stem (31) to move in said central opening (36) in the sealing washer (34) in a direction perpendicular to the thickness direction of the tank wall.
3. The sealed and thermally insulating tank as claimed in claim 1 or 2, in which the primary anchoring member (12) further comprises a stop borne by the stem (31), said stop being arranged on the stem (31) between the bearing element (16) and the sealing washer (34), the stop having a stop surface (47) facing the sealing washer (34) so as to stop a movement of said sealing washer (34), relative to the stem (31), toward the primary sealed membrane (4) in the thickness direction of the tank wall.
4. The sealed and thermally insulating tank as claimed in claim 3, in which the stem (31) has a shoulder (48), said shoulder (48) projecting laterally from the stem (31) beyond the central opening (36) in the sealing washer (34) in such a way that an outer face (49) of said shoulder (48) forms the stop surface (47).
5. The sealed and thermally insulating tank as claimed in one of claims 1 to 4, in which the primary anchoring member (12) further comprises a bell (43) mounted on the stem (31), said bell (43) comprising a mounting portion (44) and a protective portion (45), the mounting portion (44) having a central passage through which the stem (31) passes, the protective portion (45) extending in the thickness direction of the tank wall from the mounting portion (44) toward the sealing washer (34), the protective portion (45) being hollow, the deformable seal (42) being housed in the protective portion (45).
6. The sealed and thermally insulating tank as claimed in claim 3 in combination with claim 5, in which an outer end of the protective portion (45) opposite to the mounting portion (44) forms the stop surface (37) facing the sealing washer (34).
7. The sealed and thermally insulating tank as claimed in claim 5 or 6, in which the bell (43) is secured to the stem (31).
8. The sealed and thermally insulating tank as claimed in one of claims 5 to 7, further comprising a transfer wedge arranged around the bell in a gap between the bell and the adjacent primary insulating panels.
9. The sealed and thermally insulating tank as claimed in one of claims 5 to 8, in which the sealing washer (34) comprises a flat portion (85) and the bell (43) comprises a flat portion (89), said flat portions being configured to be gripped by a screwing tool so that the stem (31) and the sealing washer (34) rotate together, without twisting of the deformable seal (42).
10. The sealed and thermally insulating tank as claimed in one of claims 1 to 9, in which the deformable seal comprises a deformable bellows (42), said deformable bellows (42) being hollow and extending around and axially along the stem (31), a first axial end of said bellows (42) being secured sealingly to the stem (31) and a second axial end of said bellows (42) being secured sealingly to the sealing washer (34).
11. The sealed and thermally insulating tank as claimed in claim 10, in which the bellows (42) has at least three folds.
12. The sealed and thermally insulating tank as claimed in claim 10 or 11, in which the bellows (42) has a flared shape, the second axial end of the bellows (42) secured to the sealing washer (34) having a circumferential dimension greater than the circumferential dimension of the first axial end of the bellows (42) secured to the stem (31).
13. The sealed and thermally insulating tank as claimed in one of claims 1 to 12, in which the base (30) of the primary anchoring member (12) is rigidly anchored in the secondary insulating barrier (1).
14. The sealed and thermally insulating tank as claimed in one of claims 1 to 13, in which an inner end of the stem (31) opposite to the base (30) is threaded, and in which the primary anchoring member (12) further comprises a nut (32) screwed onto said inner threaded end, the bearing element (16, 54) being inserted between said nut (32) and the base (30) of the primary anchoring member (12), the deformable seal being inserted between the bearing element (16, 54) and the sealing washer (34).
15. The sealed and thermally insulating tank as claimed in claim 14, in which an elastic washer (33) is inserted between the nut (32) and the bearing element (16, 54).
16. The sealed and thermally insulating tank as claimed in one of claims 1 to 15, in which the primary anchoring member (12) has an anchoring shoulder (40) projecting laterally from the stem (31), said anchoring shoulder (40) forming an anchoring surface (41) extending in a plane perpendicular to the thickness direction, said anchoring surface (41) facing the bearing element (16, 54), the deformable seal being secured sealingly to said anchoring surface (41).
17. A carrier (70) for the transport of a cold liquid product, the carrier comprising a double hull (72) and a tank as claimed in one of claims 1 to 16 arranged in the double hull.
18. A transfer system for transferring a cold liquid product, the system comprising a carrier (70) as claimed in claim 17, insulated pipelines (73, 79, 76, 81) arranged so as to connect the tank installed in the hull of the carrier to a floating or onshore storage facility (77) and a pump for pumping a flow of cold liquid product through the insulated pipelines from or to the floating or onshore storage facility, to or from the tank of the carrier.
19. A method for loading or unloading a carrier (70) as claimed in claim 17, in which a cold liquid product is conveyed through insulated pipelines (73, 79, 76, 81) from or to a floating or onshore storage facility (77), to or from the tank of the carrier (71).

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