EP3161370B1 - Sealed insulating tank and method of manufacturing the same - Google Patents

Description

Technical area

The invention relates to the field of sealed and insulating vessels which may contain cold fluids, in particular tanks for storing or transporting liquefied gases, in particular liquefied natural gas at atmospheric pressure.

Technological background

We know, in particular by FR-A-2781557 a sealed and insulating tank comprising a tank wall fixed to a supporting structure, in which the wall of the tank has a multilayer structure which successively comprises a primary sealing membrane intended to be in contact with a product contained in the tank, a primary insulating barrier, a secondary waterproofing membrane and a secondary insulating barrier.

The secondary insulating barrier, the secondary sealing membrane and the primary insulating barrier consist essentially of a set of prefabricated panels fixed to the supporting structure, each prefabricated panel successively comprising a rigid bottom plate, a first layer of thermal insulation carried by the bottom plate and forming with the bottom plate an element of the secondary insulating barrier, a waterproof coating which completely covers the first layer of thermal insulation by being bonded to the first layer of thermal insulation and which forms an element of the secondary waterproofing membrane, a second thermal insulation layer which covers a central zone of the first layer and the waterproof coating, and a rigid cover plate covering the second thermal insulation layer and constituting with the second layer of thermal insulation; thermal insulation an element of the primary insulating barrier.

The bottom plate, the first layer of thermal insulation and the waterproof coating of the prefabricated panel have a first rectangular outline while the second layer of thermal insulation and the cover plate have a second rectangular contour of smaller dimensions than the first one. contour rectangular, so that the second layer of thermal insulation and the cover plate do not cover an edge region of the waterproof coating along the four edges of the first rectangular contour.

The prefabricated panels are juxtaposed on the supporting structure parallel to each other, so that the edge region of the waterproof coating of a first of the prefabricated panels is each time close to the edge region of the waterproof coating of a second of the prefabricated panels.

The wall of the vessel further comprises sealing strips made of a flexible composite laminate material comprising at least one metal sheet bonded to at least one layer of fibers, the sealing strips being arranged straddling the adjacent border areas sealed waterproofing of the prefabricated panels and sealed to the waterproofing of the prefabricated panels to complete the secondary waterproofing membrane between the prefabricated panels.

The wall of the tank further comprises insulating blocks disposed on the sealing strips, an insulating pad being placed each time between the second layers of thermal insulation of two adjacent prefabricated panels, so as to complete the primary insulating barrier between the two prefabricated panels, the insulating pad having a layer of thermal insulation covered with a rigid plate, so that the rigid plates of the insulating blocks and the cover plates of the prefabricated panels constitute a substantially continuous wall capable of supporting the membrane of primary sealing.

EP-A-0248721 discloses a thermally insulating wall structure of similar design, in which a spacer gasket made of a rigid insulating cellular material fills the gap between two adjacent sandwich panels. The intermediate seal gasket is covered by the seal strip forming the secondary sealing barrier and is adhered to said strip of gasket. The internal pad adhered to the strip of cover strips is coated on its outer face adjacent to the strip of cover of a fiberglass fabric bonded to said outer face to enhance the strength of the block. Since the pad is glued against the bottom formed by the shoulders of the sandwich panels and the inter-seal gasket, the fiberglass fabric of the pad is bonded to the seal strip also in the central portion of the seal strip covering the seal.

summary

In the tanks of the aforementioned type, deformations of all the elements occur due to the temperature changes affecting the tank wall during its filling with a very cold liquid such as LNG and, conversely, during its emptying causing a return to room temperature. In addition to these thermal effects of contraction and expansion, which are repeated over time during the life of the vessel, the vessels of vessels also undergo efforts due to the deformation of the hull of the ship to the sea. results from phenomena of fatigue of the elements, which should be monitored over time to prevent breakage.

An idea underlying the invention is to enhance the fatigue resistance of the secondary sealing membrane of a tank of the aforementioned type, in particular at the level of the sealing strips arranged straddling the edge zones of the prefabricated panels. Indeed, because of the flexural flexibility of the material used, that is to say the capacity of the material to be folded to form waves without breaking, the sealing strips are particularly subject to deformation during the life of the tank.

For this, the invention provides a tank of the aforementioned type, characterized in that the insulating pad comprises a reinforcing ply made of a composite material comprising a layer of fibers bonded by a polymer resin, the reinforcing ply having a stiffness in traction greater than or equal to the tensile stiffness of the sealing strips, the reinforcing ply being bonded to the thermal insulation layer on one side of the thermal insulating layer opposite to the rigid plate, the insulating pad being at each once fixed on the prefabricated panels by gluing the reinforcing ply onto the underlying sealing strip.

With these features, it is possible to increase the fatigue resistance of the secondary membrane, while maintaining a flexible web sealing strip at the interface between the panels, which has advantages for the reliability and durability of the secondary membrane. sealing of the bonding of the sealing strip on the coatings prefabricated panels and, where appropriate, for the mobility of the secondary membrane in response to thermal displacement.

Because the reinforcing ply consists of a composite material having a tensile stiffness greater than or equal to the tensile stiffness of the sealing strips, and because the reinforcing ply comprises a layer of fibers impregnated with a polymer resin, it makes it possible to effectively take up the tensioning forces which are established substantially parallel to the tank wall by thermal contraction and / or deformation of the carrier structure at sea. In addition, the choice of a fiber composite material limits the thermal stresses generated by the reinforcing ply.

• nature de la résine polymère, module d'Young à l'état final
• nature et diamètre des fibres.

In order to influence the tensile stiffness of the reinforcing ply, the following properties of the reinforcing ply can in particular be selected:

• nature of the polymer resin, Young's modulus in the final state
• nature and diameter of the fibers.

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

Another desirable physical property for the reinforcing strip is the relatively low coefficient of thermal expansion, which can be achieved by the choice of fibers, for example glass fibers, carbon fibers, polyester fibers and the like.

Another desirable physical property for the reinforcing strip is the good stickiness, which can be obtained in particular by the choice of the resin, which may for example be chosen from the group consisting of polyamides, polyether terephthalate, polyesters, polyurethanes, epoxides and their mixtures. On the other hand, polyethylene and polypropylene resins are more difficult to stick reliably without any specific binding treatment.

Preferably, the material of the reinforcing ply has a coefficient of thermal expansion α and a tensile Young's modulus E, measured at 23 ° C., such that their product satisfies: $${7.10}^4\mathrm{}\mathit{Pa}.K^{-1}<E.\alpha <{10}^6\mathrm{}\mathit{Pa}.K^{-1}$$

By way of example, flexural flexible composite materials such as triplex® ( E, α- 88000) are suitable for the reinforcing ply. For a value higher than about 10 ⁶ Pa.K ^{- 1} , for example in the case of a metal sheet, the thermal stress in the material during the cold setting would be too high. To a lower value approximately 7.10 Pa.K ^{4 -} (. E α ~48000) ^1, for example in the case of plywood, the rigidity would not be sufficient to effectively enhance the sealing strip web flexible.

To determine the tensile rigidity of the reinforcing ply, the Young's tensile modulus E can be used, determined according to the method NF EN ISO 1421 or using extensometers. The coefficient of thermal contraction α can be determined by an optical system or a comparator system mounted on an invar frame, to have a virtually zero contribution of the frame.

The flexible composite laminate material of the sealing strip can be made in different ways as to the composition, number and arrangement of the layers, especially with one or more metal layers and one or more layers of fibers. According to one embodiment, the sealing strip is made of a flexible composite laminate material comprising a metal sheet sandwiched between two layers of glass fibers. For example, the metal foil is aluminum. The two layers of glass fibers are bonded to the metal sheet by a flexible polymer resin, for example elastomer or polyurethane.

According to one embodiment, the reinforcing ply is made of a flexible composite laminate material comprising at least one metal sheet bonded to at least one layer of fibers, for example of the same flexible composite laminate material as the sealing strip. The use of the same flexible composite laminate material for the sealing strips and the reinforcing ply facilitates the supply and quality control of the materials.

According to one embodiment, the waterproof coating of the prefabricated panels consists of a composite rigid flexural material comprising a metal sheet sandwiched between two layers of glass fibers, the two layers of glass fibers being impregnated with a fiberglass. rigid polymer resin. For example, the metal foil is aluminum.

According to a preferred embodiment, the reinforcing ply is made of a stiffer material in tension than the sealing strips. For this purpose, it is possible to use a flexural rigid composite material comprising a fiber layer impregnated with a rigid polymer resin, for example polyamide, polyether terephthalate, polyester, polyurethane, epoxy and their mixtures. The use of a stiffer material in tension that the flexible watertight web of the sealing strips makes it possible to effectively take up more tensioning forces which are established substantially parallel to the tank wall by thermal contraction and / or deformation of the bearing structure at sea.

According to one embodiment, the same rigid composite laminate material can be used for the watertight coating and the reinforcing ply, which facilitates the supply and the quality control of the materials.

According to one embodiment, the vessel wall comprises a gap located between the first layers of thermal insulation of two adjacent prefabricated panels and a strip of stuffing material disposed in the gap, the sealing strip which completes the membrane of secondary sealing between the prefabricated panels has a central portion crossing the gap above the web of stuffing material, the central portion of the sealing strip not being adhered to the web of stuffing material,
and the reinforcing ply has a central portion covering the central portion of the sealing strip and not being adhered to the central portion of the sealing strip.

Thanks to these characteristics, the central portion of the sealing strip has a greater flexibility and greater mobility to absorb displacements caused by the thermal contraction and / or the deformation of the ship at sea.

According to embodiments, a central pad of non-adhesive material may be fixed on the flexible sealing mat or on the reinforcing ply. The fixing of the pad can be made in different ways, in particular by double-sided adhesive or with a sticky tape. Such a pad may be of different materials, for example flexible foam elastomer type, polyurethane, polyolefins (polyethylene, polypropylene) or melamine.

According to a corresponding embodiment, the insulating pad further comprises a central pad of non-adhesive material fixed projecting on a surface of the reinforcement ply opposite the thermal insulation layer of the insulating pad, the insulating pad being placed on the sealing strip so that the central pad overlies the central portion of the sealing strip.

According to another corresponding embodiment, the sealing strip further comprises a central pad of non-adhesive material fixed projecting on a surface of the sealing strip facing the insulating pad, the insulating pad being arranged on the strip of sealing so that the central portion of the reinforcing ply covers the central pad without being glued to the central pad.

Different materials may be suitable for the thermal insulation layers of prefabricated panels and pavers. Polyurethane foams are particularly suitable materials because of their low temperature resistance and low thermal conductivity. Preferably, the polyurethane foam is reinforced with embedded fibers, for example glass fibers.

According to one embodiment, the thermal insulation consists of a polyurethane foam having a density greater than 130 kg / m ³ , for example between 130 and 210 kg / m ³ .

Thanks to these characteristics, it is possible to increase the rigidity and the durability of the insulating barriers.

Such a tank can be part of a land storage facility, for example to store LNG or be installed in a floating structure, coastal or deep water, including a LNG tank, a floating storage and regasification unit (FSRU) , a floating production and remote storage unit (FPSO) and others.

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

According to one embodiment, the invention also provides a method of loading or unloading such a vessel, in which a cold liquid product is conveyed through isolated pipes from or to a floating or land storage facility to or from the vessel vessel.

According to one embodiment, the invention also provides a transfer system for a cold liquid product, the system comprising the abovementioned vessel, insulated pipes arranged to connect the vessel installed in the hull of the vessel to a floating storage facility. or terrestrial and a pump for driving a flow of cold liquid product through the insulated pipelines from or to the floating or land storage facility to or from the vessel vessel.

• fournir un ensemble de panneaux préfabriqués, chaque panneau préfabriqué comprenant successivement une plaque de fond rigide, une première couche d'isolant thermique portée par la plaque de fond et constituant avec la plaque de fond un élément de la barrière isolante secondaire, un revêtement étanche qui recouvre complètement la première couche d'isolant thermique en étant collé sur la première couche d'isolant thermique et qui forme un élément de la membrane d'étanchéité secondaire, une deuxième couche d'isolant thermique qui recouvre une zone centrale de la première couche et du revêtement étanche, et une plaque de couvercle rigide recouvrant la deuxième couche d'isolant thermique et constituant avec la deuxième couche d'isolant thermique un élément de la barrière isolante primaire, la plaque de fond, la première couche d'isolant thermique et le revêtement étanche du panneau préfabriqué présentant un premier contour rectangulaire tandis que la deuxième couche d'isolant thermique et la plaque de couvercle présentent un deuxième contour rectangulaire de plus petites dimensions que le premier contour rectangulaire, de sorte que la deuxième couche d'isolant thermique et la plaque de couvercle ne recouvrent pas une zone de bordure du revêtement étanche le long des quatre bords du premier contour rectangulaire,
• juxtaposer et fixer les panneaux préfabriqués parallèlement les uns aux autres sur la structure porteuse, de manière que la zone de bordure du revêtement étanche d'un premier des panneaux préfabriqués est à chaque fois voisine de la zone de bordure du revêtement étanche d'un deuxième des panneaux préfabriqués,
• disposer des bandes d'étanchéité à cheval sur les zones de bordure voisines des revêtements étanches des panneaux préfabriqués, les bandes d'étanchéité étant faites en un matériau stratifié composite souple comprenant au moins une feuille métallique liée à au moins une couche de fibres et coller les bandes d'étanchéité de manière étanche aux revêtements étanches des panneaux préfabriqués pour compléter la membrane d'étanchéité secondaire entre les panneaux préfabriqués,
• fournir des pavés isolants, le pavé isolant comportant une couche d'isolant thermique, une plaque rigide fixée sur une face supérieure de la couche d'isolant thermique et une nappe de renforcement réalisée dans un matériau composite comprenant une couche de fibres liées par une résine polymère, la nappe de renforcement présentant une raideur en traction supérieure ou égale à la raideur en traction des bandes d'étanchéité, la nappe de renforcement étant collée sur une face inférieure de la couche d'isolant thermique opposée à la plaque rigide,
• disposer les pavés isolants sur les bandes d'étanchéité, un pavé isolant étant à chaque fois disposé entre les deuxièmes couches d'isolant thermique de deux panneaux préfabriqués voisins, de manière à compléter la barrière isolante primaire entre les deux panneaux préfabriqués et à former une paroi de support sensiblement continue avec les plaques rigides des pavés isolants et les plaques de couvercle des panneaux préfabriqués,
• fixer les pavés isolants sur les panneaux préfabriqués par collage de la nappe de renforcement du pavé isolant sur la bande d'étanchéité sous-jacente, et
• fixer une membrane d'étanchéité primaire sur la paroi de support sensiblement continue.

According to one embodiment, the invention also provides a method of manufacturing a sealed and insulating tank, the method comprising:

• providing a set of prefabricated panels, each prefabricated panel successively comprising a rigid bottom plate, a first layer of thermal insulation carried by the bottom plate and constituting with the bottom plate an element of the secondary insulating barrier, a waterproof coating which completely covers the first layer of thermal insulation by being bonded to the first layer of thermal insulation and which forms an element of the secondary waterproofing membrane, a second layer of thermal insulation which covers a central area of the first layer and sealing cover, and a rigid cover plate covering the second layer of thermal insulation and constituting with the second layer of thermal insulation a member of the primary insulating barrier, the bottom plate, the first layer of thermal insulation and the waterproof coating of the prefabricated panel having a first rectangular contour while the two the second thermal insulation layer and the cover plate have a second rectangular outline of smaller dimensions than the first rectangular outline, so that the second thermal insulating layer and the cover plate do not cover an edge area of the cladding. sealed along the four edges of the first rectangular contour,
• juxtaposing and fixing the prefabricated panels parallel to each other on the supporting structure, so that the edge region of the waterproof coating of a first of the prefabricated panels is each time close to the edge region of the waterproof coating of a second prefabricated panels,
• having the sealing strips straddling adjacent edge areas of the prefabricated panel waterproofing coatings, the sealing strips being made of a flexible composite laminate material comprising at least one metal sheet bonded to at least one layer of fibers and bonding the sealing strips sealingly to the waterproof coatings of prefabricated panels for complete the secondary waterproofing membrane between the prefabricated panels,
• providing insulating pavers, the insulating pad having a thermal insulating layer, a rigid plate attached to an upper face of the thermal insulating layer and a reinforcing ply made of a composite material comprising a layer of resin-bonded fibers polymer, the reinforcing ply having a tensile stiffness greater than or equal to the tensile stiffness of the sealing strips, the reinforcing ply being bonded to a lower face of the thermal insulating layer opposite to the rigid plate,
• arranging the insulating pavers on the sealing strips, an insulating pad being placed each time between the second layers of thermal insulation of two adjacent prefabricated panels, so as to complete the primary insulating barrier between the two prefabricated panels and to form a substantially continuous support wall with the rigid plates of the insulating pavers and the cover plates of the prefabricated panels,
• attaching the insulating pavers to the prefabricated panels by bonding the reinforcing ply of the insulating pad to the underlying sealing strip, and
• attaching a primary waterproofing membrane to the substantially continuous support wall.

In some embodiments, this method may include one or more of the following features.

• disposer une bande de matériau de bourrage dans un interstice localisé entre les premières couches d'isolant thermique de deux panneaux préfabriqués voisins, disposer la bande d'étanchéité qui complète la membrane d'étanchéité secondaire entre les panneaux préfabriqués sans coller à la bande de matériau de bourrage une portion centrale de la bande d'étanchéité qui franchit l'interstice au-dessus de la bande de matériau de bourrage, et
• fixer le pavé isolant comportant la nappe de renforcement sans coller une portion centrale de la nappe de renforcement sur la bande d'étanchéité.

According to one embodiment, the method further comprises:

• disposing a strip of stuffing material in a gap located between the first layers of thermal insulation of two neighboring prefabricated panels, arranging the sealing strip which completes the secondary sealing membrane between the prefabricated panels without sticking to the strip of material stuffing a central portion of the sealing strip that crosses the gap above the web of stuffing material, and
• fixing the insulating pad comprising the reinforcing ply without bonding a central portion of the reinforcing ply to the sealing strip.

According to one embodiment, the insulating pad further comprises a central pad of non-adhesive material fixed projecting on a surface of the reinforcement ply opposite the thermal insulating layer of the insulating pad,
the method further comprising the step of bonding the reinforcing ply of the pavement isolating on either side of the central pad without gluing the central pad, and arranging the insulating pad on the sealing strip so that the central pad covers the central portion of the sealing strip without adhering thereto.

According to another embodiment, the sealing strip further comprises a central pad of non-adhesive material fixed projecting on a surface of the sealing strip facing the insulating pad,
the method further comprising the step of gluing the sealing strip on either side of the central pad without gluing the central pad, and arranging the insulating pad on the sealing strip so that the central portion of the reinforcing ply covers the central pad without being glued to the central pad.

Brief description of the figures

• La figure 1 est une vue en perspective partiellement éclatée d'une paroi de cuve selon un mode de réalisation.
• La figure 2 est une vue plane éclatée d'une zone de la paroi de cuve de la figure 1 située à l'interface entre deux panneaux préfabriqués.
• La figure 3 est une vue analogue à la figure 2 montrant la zone de la paroi de cuve à l'état assemblé.
• La figure 4 est une vue analogue à la figure 2 montrant un autre mode de réalisation de la zone de paroi située à l'interface entre deux panneaux préfabriqués.
• La figure 5 est une courbe de fatigue représentant l'effort à la rupture de la membrane secondaire en fonction d'un nombre de cycles de refroidissement-réchauffage, pour différents modes de réalisation du pavé isolant.
• La figure 6 est une représentation schématique écorchée d'une cuve de navire méthanier et d'un terminal de chargement/déchargement de cette cuve.

The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly in the course of the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes. with reference to the accompanying drawings.

• The figure 1 is a partially exploded perspective view of a vessel wall according to one embodiment.
• The figure 2 is an exploded flat view of an area of the tank wall of the figure 1 located at the interface between two prefabricated panels.
• The figure 3 is a view similar to the figure 2 showing the area of the tank wall in the assembled state.
• The figure 4 is a view similar to the figure 2 showing another embodiment of the wall area at the interface between two prefabricated panels.
• The figure 5 is a fatigue curve representing the breaking force of the secondary membrane according to a number of cooling-heating cycles, for different embodiments of the insulating pad.
• The figure 6 is a cutaway schematic representation of a tank of LNG tanker and a loading / unloading terminal of this tank.

Detailed description of embodiments

With reference to the figure 1 an embodiment of a tank wall in which the secondary insulating barrier, the secondary waterproofing membrane and the primary insulating barrier are made from prefabricated panels 54 is now described.

Such a wall structure can be used to make substantially all the walls of a polyhedral vessel. In this respect, the terms 'on', 'above', 'upper' and 'high' generally refer to a position located inwardly of the vessel and therefore do not necessarily coincide with the notion of high in the terrestrial gravitational field. Similarly, the terms 'sub', 'below', 'lower' and 'lower' generally refer to a position located outside the vessel and therefore do not necessarily coincide with the notion of low in the gravitational field. earthly.

The prefabricated panels 54 are fixed on the supporting structure juxtaposed in a repeated pattern. A panel 54 each comprises an element of the secondary insulating barrier 51, an element of the secondary sealed barrier and an element of the primary insulating barrier 53.

A panel 54 has substantially the shape of a rectangular parallelepiped. It consists of a first plate 9 mm plywood 9 mm thick surmounted by a first layer of thermal insulation 56, itself surmounted by a rigid waterproof coating 52 including an aluminum sheet of 0, 07 mm thick sandwiched between two glass fiber fabrics impregnated with a polyamide resin. The waterproof coating 52 is bonded to the thermal insulation layer 56, for example using a two-component polyurethane adhesive.

A second layer of thermal insulation 57 is adhered to the waterproof coating 52 and itself carries a second plywood plate 58 of 12 mm thickness. The subassembly 55-5E constitutes the secondary insulation barrier element 51. The subassembly 57-58 constitutes the insulation barrier element primary 53 and has, in plan, a rectangular shape whose sides are parallel to those of the secondary insulation barrier element 51. The two insulation barrier elements have, seen in plan, the shape of two rectangles having the same center. The member 53 reveals a peripheral rim surface 59 of the impervious liner 52 all around the member 53. The impervious liner 52 forms the secondary sealing membrane member.

The panel 54, which has just been described, may be prefabricated to form an assembly in which the various components are glued to one another in the arrangement indicated above. This set therefore forms the secondary barriers and the primary insulation barrier. The thermal insulation layers 56 and 57 may be constituted by a cellular plastic material such as a polyurethane foam. Preferably, glass fibers are embedded in the polyurethane foam to reinforce it.

To ensure the fixing of the panels 54 on the carrier structure 99, wells 60 are regularly distributed over the two longitudinal edges of the panel to cooperate with studs fixed on the supporting structure 99 according to the known technique.

The carrying structure 99, especially in the case of a ship, has deviations from the theoretical surface provided for the bearing structure simply because of manufacturing inaccuracies. In a known manner, these gaps are made up by placing the panels 54 in abutment against the supporting structure by means of polymerizable resin strands 61, which make it possible, from a surface of imperfectly bearing structure, to obtain a covering consisting of by adjacent panels 54 having second plates 58 which, as a whole, define a surface substantially devoid of the desired theoretical surface.

The wells 60 are closed by inserting plugs of thermal insulating material 62, these plugs flush with the first layer of thermal insulation 56 of the panel 54. In addition, it is possible to place in the interstices which separate the elements 51. two adjacent panels 54, a heat insulating material 63 consisting of, for example, a sheet of plastic foam or glass wool inserted into the gap.

To constitute a continuous secondary waterproofing membrane, a flexible waterproof strip 65 is placed on the peripheral rims 59 adjacent to two adjacent panels 54, and the sealing strip 65 is bonded to the peripheral rims 59 so as to seal the perforations located at the right of each well 60 and covering the gap between the two panels 54. The waterproof strip 65 is made of a composite material called triplex® flexible comprising three layers: the two outer layers are fiberglass fabrics and the intermediate layer is a thin metal sheet, for example an aluminum foil with a thickness of about 0.1 mm. This metal sheet ensures the continuity of the secondary waterproofing membrane. Its flexural flexibility, because of the flexible nature of the binder between the aluminum foil and the glass fibers, allows it to follow the deformations of the panels 54 due to the deformation of the hull to the swell or the cold setting of the tank. Flexibility in bending means the ability of the material to be bent to form waves without breaking.

Between the elements 53 of two adjacent panels 54 remains a depressed zone located at the right of the peripheral rims 59, this depression having substantially the depth of the thickness of the primary insulation barrier. These areas of depression are filled by putting in place insulating pavers 66 each consisting of a thermal insulation layer 67 coated with a rigid plywood plate 68 on an upper surface of the insulating pad 66 and a sheet reinforcement on the lower surface of the insulating pad 66. The reinforcing ply not visible on the figure 1 will be described with reference to Figures 2 to 4 .

The insulating pavers 66 have a dimension such that they completely fill the area located above the peripheral rims 59 of two adjacent panels 54. The insulating blocks 66 are glued on the sealing strips 65. After being put in place, the plate 68 provides a relative continuity between the plates 58 of two adjacent panels 54 for supporting the primary waterproofing membrane.

These insulating pavers 66 have a width equal to the distance between two elements 53 of two adjacent panels 54 and may have a greater or lesser length. A reduced length allows, if necessary, an easier implementation in the event of a slight misalignment of two panels 54 adjacent. The blocks 66 are glued to the sealing strip 65 and resting on it.

The primary sealing membrane is formed of an embossed sheet membrane 69 having two series of intersecting corrugations to give it sufficient flexibility in both directions of the plane of the vessel wall.

On the figure 1 , the insulating pavers 66, the watertight strip 65 and the thermal insulation materials 62 and 63 are shown in an exploded form and thus appear above their actual position in the assembled end-wall of the tank. The final positions of these elements are better visible on the figure 3 which will be described below.

With reference to Figures 2 and 3 a first embodiment of the vessel wall at the junction between two prefabricated panels 54 will now be described. figure 2 partially represents the two prefabricated panels 54 fixed on the supporting structure 99 in their final position, while the insulating pad 66, the reinforcing ply 1 of the insulating pad 66 and the sealing strip 65 are shown in the disassembled state above their final position. The figure 3 represents all the elements in their final assembled position. The thicknesses of the watertight coating 52, the watertight strip 65, the reinforcing ply 1 and the corresponding glue layers have been exaggerated for the sake of visibility.

The reinforcing ply 1 is bonded to the lower surface 2 of the thermal insulating layer 67 by means of a glue layer 3. This gluing can be done in prefabrication in order to deliver to the assembly site of the tank a insulating pad 66 already comprising the reinforcing ply 1. The glue 3 is for example an epoxy or polyurethane glue.

• Une couche de colle 4 est disposée sur la surface de bordure périphérique 59 du revêtement étanche 52 des deux panneaux préfabriqués 54.
• La bande étanche 65 est ensuite appliquée et pressée sur la couche de colle 4 jusqu'à ce que la colle soit prise. La colle 4 est par exemple une colle époxy ou polyuréthane. Comme visible sur la figure 3, la bande étanche 65 n'est pas collée au niveau d'une portion centrale 6 de sa surface inférieure qui enjambe l'interstice entre les deux panneaux 54, lequel mesure environ 30mm.
• Une deuxième couche de colle 5 est ensuite disposée, soit sur la surface inférieure de la nappe de renforcement 1 du pavé isolant 66, soit sur la surface supérieure de la bande étanche 65.
• Enfin le pavé isolant 66 est appliqué et pressé contre la surface supérieure de la bande étanche 65 jusqu'à ce que la colle 5 soit prise.

The assembly process is as follows:

• An adhesive layer 4 is disposed on the peripheral edge surface 59 of the impervious coating 52 of the two prefabricated panels 54.
• The sealing strip 65 is then applied and pressed onto the adhesive layer 4 until the adhesive is set. The glue 4 is for example an epoxy glue or polyurethane. As visible on the figure 3 , the watertight strip 65 is not glued at a central portion 6 of its lower surface which spans the gap between the two panels 54, which measures about 30mm.
• A second layer of adhesive 5 is then placed either on the lower surface of the reinforcing ply 1 of the insulating block 66 or on the upper surface of the impervious strip 65.
• Finally the insulating pad 66 is applied and pressed against the upper surface of the sealing strip 65 until the adhesive 5 is taken.

The glue 5 is for example a relatively viscous epoxy or polyurethane glue, which makes it possible to apply a layer that is thick enough to take up the surface irregularities of the reinforcing ply 1. It is indeed important that, in the assembled state, the Rigid plates 68 and 58 generally provide a flat surface support surface for uniformly supporting the primary waterproofing membrane 69, which is made of a thin and relatively brittle material.

Preferably, it is avoided to apply the layer of adhesive 5 in line with the central portion 6 of the sealing strip 65, so as to preserve the elasticity and mobility of this central portion 6 by not sticking any of its two faces.

The figure 4 represents a second embodiment of the vessel wall at the junction between two prefabricated panels 54 in which the insulating pad has been modified to avoid applying the adhesive layer 5 to the plumb with the central portion 6 of the 65. The elements identical or similar to those of the previous embodiment have the same reference numeral.

On the figure 4 , the insulating pad 66 additionally carries a non-adhesive pad 10, made for example of polymer foam or thick paper, which is bonded to the lower surface of the reinforcing ply 1, at a central line of the insulating pad 66 intended to to cover the central portion 6 of the sealing strip 65. The gluing of the pad 10 to the reinforcing ply 1 can be made in different ways, for example by means of a glue line 11 or a double-sided tape or by providing the pad 10 with an adhesive tape. The pad 10 can also be assembled in prefabrication to minimize the operations to be performed on the assembly site of the tank.

For fastening the insulating pad 66 to the tank wall, the lower surface of the reinforcement ply 1 is glued with the adhesive layer 5 on either side of the non-adhesive pad 10, without adhering the non-adhesive pad 10. Thus, once the final assembly is made, the upper surface of the central portion 6 of the strip waterproof 65 is in contact with the non-adhesive pad 10 without being glued, which promotes its flexibility and mobility to absorb displacement of thermal origin.

In a mode not shown on the figure 4 but constituting a variant, the shoe 10 is fixed, not on the reinforcing ply 1, but on the flexible ply 65, for example with a double-sided tape or an adhesive tape to ensure its positioning.

Exemplary embodiments of the vessel wall will now be described for illustrative purposes and their mechanical properties of resistance to fatigue will be described with reference to the figure 5 . The figure 5 represents the breaking force of the sealing strip 65 expressed in kilo Newton (kN) as a function of the average service life of the vessel wall, expressed as an average number of cold-running cycles.

Example 1

The thermal insulation of the layers 56, 57 and 67 is a polyurethane foam reinforced with glass fibers with a density of 130 kg / m ³ . The thickness of the primary insulating barrier is 150 mm. The thickness of the secondary insulating barrier is 250 mm. The operating temperature of the secondary membrane is approximately - 80 ° C.

The watertight strip 65 is a flexible triplex® with a thickness equal to 0.6 mm (aluminum, resin, fiberglass) supplied by the company Hutchinson. The width of this band is of the order of 250 mm. Its tensile Young modulus is E = 10 GPa and its coefficient of thermal expansion at 23 ° C is α = 0.9.10 ^-5 K ^{- 1} . The tensile stress at break, measured at 23 ° C, is about 200 MPa. This material is usually packaged in rolls because of its flexibility.

Glue 4 is a two-component polyurethane glue provided by Bostik under the reference XPU 18411 A / 3B.

The reinforcement ply 1 is a rigid triplex with a thickness of 0.6 mm (aluminum, fiberglass, polyamide resin) supplied by Hankuk. Its tensile Young's modulus is E = 15 GPa and its coefficient of thermal expansion at 23 ° C is α = 10 ^-5 K ^-1 . The tensile stress at break, measured at 23 ° C, is about 210 MPa. The central portion of the reinforcing ply 1 is also bonded to the waterproof band 65. This material is usually packaged in flat plates, because of its relative rigidity.

The adhesive 3 is a two-component polyurethane adhesive supplied by Henkel under the reference Macroplast 8202/5400.

The adhesive 5 is an epoxy resin supplied by the company Unitech under the reference UEA 100/300.

An endurance test is performed in the form of a series of cold-reheat cycles between the ambient temperature and the LNG temperature (-162 ° C). The watertight strip 65 holds 70000 cycles before crossing a threshold of reference effort shown by the line 12 of the figure 5 . This threshold corresponds to the breakage of a material of the whole of the insulation.

Curve 14 of the figure 5 is an average fatigue curve for the watertight strip 65.

Moreover, in this configuration, a numerical simulation of the tank wall at the operating temperature predicts a tension stress in the sealing strip 65 of the order of 63 MPa, which is very largely below the stress of rupture of the flexible triplex®, close to 200 MPa.

Comparative Example 1

The reinforcing ply 1 and the glue layer 3 are removed. For the rest, the data of example 1 are retained. The watertight strip 65 holds 35000 cycles before crossing the reference stress threshold shown by the line 12 of the figure 5 .

Curve 15 of the figure 5 is an average fatigue curve for the watertight strip 65 resulting from the extrapolation of Comparative Example 1. The service life of the watertight strip 65 obtained in Comparative Example 1 is less than 50% of the service life obtained. in example 1.

Furthermore, in this configuration, a numerical simulation of the tank wall at the operating temperature predicts a voltage stress in the sealed band 65 of the order of 117 MPa.

Example 2

The reinforcing ply 1 is a triplex® flexible thickness equal to 0.6 mm (aluminum, fiberglass) provided by the company Hutchinson. Its tensile Young's modulus is E = 10 GPa and its coefficient of thermal expansion at 23 ° C is α = 0.9.10 ^-5 K ^-1 . The tensile stress at break, measured at 23 ° C, is about 200 MPa.

For the rest, the data of example 1 are retained.

A numerical simulation of the tank wall at the operating temperature predicts a tension stress in the sealing strip 65 of the order of 74 MPa, which is also very largely below the breaking stress of the flexible triplex®, close to 200 MPa.

The technique described above for producing a tank wall can be used in different types of tanks, for example to form an LNG tank in a land installation or in a floating structure such as a LNG tank or other.

With reference to the figure 6 , a cutaway view of a LNG tanker 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary waterproof membrane intended to be in contact with the LNG contained in the tank, a secondary sealed membrane arranged between the primary waterproof membrane and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary waterproof membrane and the secondary waterproof membrane and between the secondary waterproof membrane and the double shell 72.

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

The figure 6 represents an example of a marine terminal comprising a loading and unloading station 75, an underwater pipe 76 and an onshore installation 77. The loading and unloading station 75 is an off-shore fixed installation comprising a movable arm 74 and a tower 78 which supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 that can connect to the loading / unloading pipes 73. The movable arm 74 can be adapted to all gauges LNG carriers. A conduct of link 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 onshore installation 77. This includes storage tanks of liquefied gas 80 and connecting lines 81 connected by the underwater line 76 to the loading or unloading station 75. The underwater line 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the installation on land 77 over a large distance, for example 5 km, which keeps the LNG tanker 70 at a great distance from the coast during the loading and unloading operations.

In order to generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the shore installation 77 and / or pumps equipping 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 not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention as defined by the claims. The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps other than those set out in a claim. The use of the indefinite article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps.

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

Claims (16)

1. A sealed insulating tank having a tank wall fixed on a supporting structure (99), in which the tank wall has a multilayer structure which comprises, successively, a primary sealing membrane (69) intended to be in contact with a product contained in the tank, a primary insulating barrier, a secondary sealing membrane, and a secondary insulating barrier,
   in which the secondary insulating barrier, the secondary sealing membrane, and the primary insulating barrier essentially consist of a set of prefabricated panels (54) fixed on the supporting structure, each prefabricated panel comprising, successively, a rigid base board (55), a first layer of thermal insulation (56) carried by the base board and forming, with the base board, an element of the secondary insulating barrier, a leaktight lining (52) which completely covers the first layer of thermal insulation, being glued to the first layer of thermal insulation, and which forms an element of the secondary sealing membrane, a second layer of thermal insulation (57) which covers a central zone of the first layer and of the leaktight lining, and a rigid cover board (58) covering the second layer of thermal insulation and forming, with the second layer of thermal insulation, an element of the primary insulating barrier,
   in which the base board, the first layer of thermal insulation and the leaktight lining of the prefabricated panel have a first rectangular contour, whilst the second layer of thermal insulation and the cover board have a second rectangular contour with smaller dimensions than the first rectangular contour, with the result that the second layer of thermal insulation and the cover board do not cover an edge zone (59) of the leaktight lining along the four edges of the first rectangular contour,
   and in which the prefabricated panels are juxtaposed on the supporting structure, parallel to one another, so that the edge zone of the leaktight lining of a first prefabricated panel each time adjoins the edge zone of the leaktight lining of a second prefabricated panel,
   the wall of the tank furthermore has sealing strips (65) made from a flexible composite laminate material comprising at least one metal sheet bound to at least one fibrous layer, the sealing strips being arranged so that they overlap the adjoining edge zones (59) of the leaktight linings of the prefabricated panels (54) and glued leaktightly to the leaktight linings (52) of the prefabricated panels in order to complete the secondary sealing membrane between the prefabricated panels, the wall of the tank furthermore has insulating blocks (66) arranged on the sealing strips, an insulating block being each time arranged between the second layers of thermal insulation of two adjoining prefabricated panels so as to complete the primary insulating barrier between the two prefabricated panels, the insulating block having a layer of thermal insulation (67) covered with a rigid board (68), with the result that the rigid boards of the insulating blocks and the cover boards of the prefabricated panels form a substantially continuous wall capable of supporting the primary sealing membrane,
   in which the insulating block has a reinforcing mat (1) comprising a layer of fibers, the reinforcing mat being glued to the layer of thermal insulation on a face of the layer of thermal insulation (67) opposite the rigid board (68), the insulating block being each time fixed to the prefabricated panels by gluing the reinforcing mat (1) to the underlying sealing strip (65),
   characterized in that the reinforcing mat consists of a composite laminate material comprising at least one metal sheet sandwiched between two layers of glass fibers bound together by a polymeric resin, and in that the reinforcing mat has a stiffness under tension which is greater than or equal to the stiffness under tension of the sealing strips (65).
2. The tank as claimed in claim 1, in which the material of the reinforcing mat has a coefficient of thermal expansion α and a Young's modulus under tension E, measured at 23°C, such that the following is true of their product: 7.10⁴ Pa. K ^-1 < E.α < 10⁶ Pa.K ^-1 .
3. The tank as claimed in claim 1 or 2, in which the composite laminate material forming the reinforcing mat (1) is flexible.
4. The tank as claimed in claim 1 or 2, in which the composite laminate material forming the reinforcing mat (1) is flexurally rigid, the said layers of glass fibers being impregnated with a rigid polymeric resin.
5. The tank as claimed in one of claim 1 to 4 in which the sealing strip (65) consists of a flexible composite laminate material comprising a metal sheet sandwiched between two layers of glass fibers, and
   in which the leaktight lining (52) of the prefabricated panels consists of a flexible composite laminate material comprising a metal sheet sandwiched between two
   layers of glass fibers, the two layers of glass fibers being impregnated with a rigid polymeric resin,
   the reinforcing mat being made from the same material as the sealing strip (65) or the leaktight lining (52).
6. The tank as claimed in one of claims 1 to 5, in which the tank wall has a gap located between the first layers of thermal insulation of two adjoining prefabricated panels (54) and a blocking strip of material (63) arranged in the gap, the sealing strip (65) which completes the secondary sealing membrane between the prefabricated panels has a central portion (6) which bridges the gap above the blocking strip of material, the central portion of the sealing strip not being glued to the blocking strip of material
   and in which the reinforcing mat (1) has a central portion covering the central portion of the sealing strip and not being glued to the central portion (6) of the sealing strip.
7. The tank as claimed in claim 6, in which the insulating block furthermore has a central pad (10) made from non-adhesive material fixed so that it projects from a surface of the reinforcing mat opposite the layer of thermal insulation of the insulating block, the insulating block being arranged on the sealing strip in such a way that the central pad covers the central portion (6) of the sealing strip (65).
8. The tank as claimed in claim 6, in which the sealing strip furthermore has a central pad (10) made from non-adhesive material fixed so that it projects from a surface of the sealing strip facing the insulating block, the insulating block being arranged on the sealing strip in such a way that the central portion of the reinforcing mat (1) covers the central pad without being glued to the central pad.
9. The tank as claimed in one of claims 1 to 8, in which the first layer of thermal insulation of the prefabricated panel, the second layer of thermal insulation of the prefabricated panel, and the layer of thermal insulation of the insulating block are made from a polyurethane foam having a density greater than 130 kg/m³, for example between 130 and 210 kg/m³.
10. A vessel (70) for transporting a cold liquid product, the vessel having a double hull (72) and a tank (71) as claimed in one of claims 1 to 9 arranged in the double hull.
11. A method for loading or unloading a vessel (70) as claimed in claim 10, in which a cold liquid product is conveyed through insulated pipelines (73, 79, 76, 81) from or to a floating or onshore storage installation (77) to or from the tank of the vessel (71).
12. A transfer system for a cold liquid product, the system comprising a vessel (70) as claimed in claim 10, insulated pipelines (73, 79, 76, 81) arranged so as to connect the tank (71) installed in the hull of the vessel to a floating or onshore storage installation (77) and a pump for forcing a flow of cold liquid product through the insulated pipelines from or to the floating or onshore storage installation to or from the tank of the vessel.
13. A method for manufacturing a sealed insulating tank, the method comprising:

    providing a set of prefabricated panels (54), each prefabricated panel comprising, successively, a rigid base board (55), a first layer of thermal insulation (56) carried by the base board and forming, with the base board, an element of the secondary insulating barrier, a leaktight lining (52) which completely covers the first layer of thermal insulation being glued to the first layer of thermal insulation and which forms an element of the secondary sealing membrane, a second layer of thermal insulation (57) which covers a central zone of the first layer and the leaktight lining, and a rigid cover board (58) covering the second layer of thermal insulation and

    forming, with the second layer of thermal insulation, an element of the primary insulating barrier, the base board, the first layer of thermal insulation and the leaktight lining of the prefabricated panel having a first rectangular contour, whilst the second layer of thermal insulation and the cover board have a second rectangular contour of smaller dimensions than the first rectangular contour, with the result that the second layer of thermal insulation and the cover board do not cover an edge zone (59) of the leaktight lining along the four edges of the first rectangular contour,

    juxtaposing and fixing the prefabricated panels parallel to one another on the supporting structure (99) in such a way that the edge zone of the leaktight lining of a first prefabricated panel each time adjoins the edge zone of the leaktight lining of a second prefabricated panel,

    arranging sealing strips (65) so that they overlap the adjoining edge zones of the leaktight linings of the prefabricated panels, the sealing strips (65) being made from a flexible composite laminate material comprising at least one metal sheet bound to at least one fibrous layer and gluing the sealing strips (65) leaktightly to the leaktight linings (52) of the prefabricated panels in order to complete the secondary sealing membrane between the prefabricated panels,

    providing insulating blocks (66), the insulating panel having a layer of thermal insulation (67), a rigid board (68) fixed to an upper face of the layer of thermal insulation and a reinforcing mat (1) glued to a lower face of the layer of thermal insulation opposite the rigid board, the reinforcing mat (1) being made from a composite laminate material comprising at least one metal sheet sandwiched between two layers of glass fibers bound together by a polymeric resin, the reinforcing mat having a stiffness under tension which is greater than or equal to the stiffness under tension of the sealing strips (65),

    arranging the insulating blocks (66) on the sealing strips (65), an insulating block being each time arranged between the second layers of thermal insulation of two adjoining prefabricated panels in such as way as to complete the primary insulating barrier between the two prefabricated panels and to form a support wall which is substantially continuous with the rigid boards of the insulating blocks and the cover boards of the prefabricated panels,

    fixing the insulating blocks to the prefabricated panels by gluing the reinforcing mat of the insulating block to the underlying sealing strip, and

    fixing a primary sealing membrane (59) to the substantially continuous support wall.
14. The method as claimed in claim 13, furthermore comprising:

    arranging a blocking strip of material (63) in a gap located between the first layers of thermal insulation of two adjoining prefabricated panels,

    arranging the sealing strip which completes the secondary sealing strip between the prefabricated panels without gluing to the blocking strip of material a central portion of the sealing strip which bridges the gap above the blocking strip of material, and fixing the insulating block having the reinforcing mat without gluing a central portion (6) of the reinforcing mat to the sealing strip (65).
15. The method as claimed in claim 14, in which the insulating block furthermore has a central pad (10) made from non-adhesive material fixed so that it projects from a surface of the reinforcing mat opposite the layer of thermal insulation of the insulating block,
    the method furthermore comprising the step of gluing the reinforcing mat (1) of the insulating block on either side of the central pad without gluing the central pad (10), and of arranging the insulating block on the sealing strip in such a way that the central pad covers the central portion (6) of the sealing strip without adhering to it.
16. The method as claimed in claim 14, in which the sealing strip furthermore has a central pad (10) made from non-adhesive material fixed so that it projects from a surface of the sealing strip facing the insulating block,
    the method furthermore comprising the step of gluing the sealing strip on either side of the central pad without gluing the central pad (10), and of arranging the insulating block on the sealing strip in such a way that the central portion of the reinforcing mat (1) covers the central pad without being glued to the central pad.

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