EP3004719A2

EP3004719A2 - Method for manufacturing a freestanding body for thermal insulation of a vessel for storing a fluid and freestanding body produced thereby

Info

Publication number: EP3004719A2
Application number: EP14734867.6A
Authority: EP
Inventors: Bruno Deletre; Olivier Perrot; Sébastien DELANOE; Florent OUVRARD; Benoît CAPITAINE; Nicolas WALKER; Gery Canler
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2013-06-07
Filing date: 2014-06-02
Publication date: 2016-04-13
Anticipated expiration: 2034-06-02
Also published as: JP2016524679A; FR3006661B1; KR20160016866A; CN105263826A; KR102263150B1; EP3004719B1; WO2014195614A2; AU2014276646A1; FR3006661A1; CN105263826B; ES2785383T3; WO2014195614A3; AU2014276646B2; JP6336051B2

Abstract

The invention relates to a method for manufacturing a freestanding body intended for thermal insulation of a vessel, with moisture barrier, for storing a fluid, said method comprising: providing a plurality of supporting webs (14) made of a composite material comprising a thermoplastic matrix reinforced by fibres; providing a bottom panel (10) and a cover panel (11); inserting the supporting webs (14) between the bottom panel (10) and the cover panel (11), such that the bottom panel (10) and the cover panel (11) are separated in the thickness direction of the body and that the supporting webs (14) extend vertically in the thickness direction; attaching the supporting webs (14) to the bottom panel (10) and to the cover panel (11); filling a plurality of compartments (15) arranged between the supporting webs (14) with a heat-insulating filler; wherein the bottom panel (10) and the cover panel (11) each comprise at least one thermoplastic element (21, 22) for attaching the supporting webs (14); and wherein the supporting webs (14) are attached to the bottom panel and to the cover panel by a thermoplastic welding operation performed at the interface areas (25) between the supporting webs (14) and the thermoplastic elements (21, 22) of the bottom panel (10) and the cover panel (11). The invention also relates to a body manufactured thereby, and to a sealed, thermally insulating vessel comprising a thermal-insulation barrier including a plurality of bodies such as mentioned above.

Description

Method of manufacturing a self-supporting body for the thermal insulation of a fluid storage tank and self-supporting body thus produced

Technical area

The invention relates to the field of sealed and thermally insulating tanks, with membranes, for storing and / or transporting fluid, such as a cryogenic fluid.

Watertight and thermally insulated membrane tanks are used in particular for the storage of liquefied natural gas (LNG), which is stored at atmospheric pressure at about -162 ° C. These tanks can be installed on the ground or on a floating structure. In the case of a floating structure, the tank may be intended for the transport of liquefied natural gas or to receive liquefied natural gas used as fuel for the propulsion of the floating structure.

Technological background

The document FR 2 877 639 describes a sealed and thermally insulating tank comprising a tank wall, fixed to the supporting structure of a floating structure and having successively, in the direction of the thickness, from the inside to the outside of the vessel, a primary sealed barrier for contacting the liquefied natural gas, a primary insulating barrier, a secondary watertight barrier and a secondary insulating barrier anchored to the supporting structure.

The insulating barriers consist of a plurality of juxtaposed parallelepiped heat insulating boxes. The parallelepipedic boxes include a plywood bottom panel, a plywood cover panel and a plurality of carrier webs interposed between the bottom panel and the cover panel. The carrier webs are corrugated so as to ensure good resistance to compressive forces, in the direction perpendicular to the bottom and cover panels, and thus withstand the hydrostatic pressure exerted by the liquid contained in the tank. The boxes are, in addition, filled with insulating linings extending in the compartments between the carrier webs. This document provides for machining grooves in the inner face of the bottom panels and cover to assemble the carrier webs to the bottom and cover panels by interlocking. However, such an assembly requires additional machining operations.

It is also known to assemble the carrier webs to the bottom and cover panels by staples. However, such staples are not appropriate when the carrier webs are made of composite material. Indeed, the attachment of the composite material sails to the bottom and cover panels by staples tends to weaken the sails.

summary

An idea underlying the invention is to propose a method of manufacturing a self-supporting body for the thermal insulation of a storage tank of a fluid in which the fixing of the carrier sails to the bottom panel and / or to the cover panel is carried out in a simple and reliable way.

According to one embodiment, the invention provides a method of manufacturing a self-supporting body for the thermal insulation of a tank, with a sealed membrane, for storing a fluid, said method comprising:

providing a plurality of carrier webs made of a composite material comprising a fiber reinforced thermoplastic matrix;

- provide a bottom panel and a cover panel;

interposing the carrier webs between the bottom panel and the cover panel, such that the bottom panel and the cover panel are spaced in a thickness direction of the body and the load-bearing sails rise in the direction thick;

- attach the load-bearing sails to the bottom panel and the cover panel; filling a plurality of compartments formed between the load-bearing sails with a heat-insulating lining;

wherein the bottom panel and the cover panel each comprise at least one thermoplastic element for attaching the carrier webs; and wherein the carrier webs are attached to the bottom panel and the cover panel by a thermoplastic welding operation performed at the interface areas between the carrier webs and the thermoplastic elements of the bottom panel and the cover panel. Thus, the carrier webs can be assembled to the bottom panel and / or the cover panel in a simple and reliable manner since the fasteners do not degrade the structural integrity of the carrier webs so that the latter are not weakened by their fixing on the bottom panel and / or on the cover panel.

According to embodiments, a method may include one or more of the following features:

the bottom panel and the cover panel each have an inner side facing the inside of the box and an outer face, the inner faces of the bottom panel and the cover panel being coated with thermoplastic film for attaching the carrier webs the inner face of the bottom panel and / or the cover panel is integrally coated with thermoplastic film.

the method comprises a step of disposing removable protective masks on the inner face of the bottom panel and / or cover between the interface areas, prior to the welding operation. Thus, it provides film protection outside the securing areas of the carrier veils.

the outer face of the bottom panel and / or the cover panel is also coated with thermoplastic film. Thus, the thermal bending of the panels is balanced during the cold setting of the tank,

the inner face of the bottom panel and / or the cover panel is partially coated with thermoplastic film, a plurality of thermoplastic film strips each being disposed in an interface area with a carrier web.

the bottom panel and / or the cover panel has a plywood body, the thermoplastic film being adhered to the plywood body.

the thermoplastic film is a composite material comprising a thermoplastic matrix reinforced with fibers. Such a thermoplastic film makes it possible to increase the bending stiffness and the punching behavior of the bottom panel and / or cover.

the bottom panel and / or the cover panel comprises a body made of a composite material comprising a thermoplastic matrix reinforced by fibers and forming a thermoplastic element for fastening the carrier webs.

the bottom panel and / or the cover panel comprises a wooden body impregnated with a thermoplastic matrix for fixing the load-bearing sails.

the thermoplastic elements are thermoplastic pins inserted inside bores formed in the bottom and / or cover panels and inside bores formed in the load-bearing sails, the thermoplastic elements for fastening the load-bearing sails comprise a thermoplastic matrix identical to the thermoplastic matrix of the carrier webs. Thus, the welding operations are facilitated.

the thermoplastic welding is performed by a method selected from infrared radiation welding, ultrasonic welding, induction heating, friction welding, melt welding, hot air jet welding and flame.

The manufacturing process provides that:

o the load-bearing sails have an upper end, intended to support a cover panel, provided with a fastening strip for anchoring a welding support for welding metal strakes of a waterproof membrane intended to come to rest against the self-supporting body, said fastening strip comprising a folded longitudinal edge intended to cooperate with a folded longitudinal edge of the welding support;

the cover panel has parallel grooves extending the full thickness of the cover panel;

the carrier webs are disposed between the bottom panel and the cover panel such that the fastening strips each extend within a groove of the cover panel.

the fastening strips are made in the mass of the carrier webs, during their forming.

a carrier web has a main body having an upper end provided with a housing and an insert comprising material thermoplastic overmolded on a fastening strip, said insert being positioned in the housing of the upper end of the main body of the carrier web and fixed to said main body by a thermoplastic welding operation.

According to one embodiment, the invention also provides a self-supporting body for the thermal insulation of a tank, with a sealed membrane, for storing a fluid, said box comprising:

a bottom panel and a cover panel spaced in a thickness direction of the body;

a plurality of carrier webs, interposed between said bottom and cover panels, and extending in the thickness direction so as to define a plurality of compartments, said carrier webs being made of a composite material comprising a reinforced thermoplastic matrix; by fibers; and

a heat-insulating lining extending inside said compartments formed between the load-bearing webs,

in which :

the bottom panel and the cover panel each comprise at least one thermoplastic element; and

- The carrier webs are attached to the bottom panel and the cover panel by thermoplastic welding in interface areas between the carrier webs and the thermoplastic elements of the bottom panel and the cover panel.

According to embodiments, such a box may include one or more of the following features:

the carrier webs have load distribution flanges extending along two edges of said carrier webs respectively disposed opposite the bottom panel and the cover panel.

- The carrier webs have a plurality of corrugations whose axis extends perpendicularly to the bottom panels and cover.

According to one embodiment, the invention also provides a method of manufacturing a self-supporting body intended for the thermal insulation of a tank, with a sealed membrane, for storing a fluid, said method comprising: providing a plurality of carrier webs made of a composite material comprising a fiber-reinforced thermoplastic matrix; said carrier webs having an upper end, for supporting a cover panel, provided with a fastening strip for anchoring a welding support for welding metal strakes of a waterproof membrane intended to rest against the self-supporting body, said fastening strip having a folded longitudinal edge intended to cooperate with a folded longitudinal edge of the welding support;

providing a bottom panel and a cover panel, the cover panel having parallel grooves extending the full thickness of the cover panel;

interposing the carrier webs between the bottom panel and the cover panel, such that the bottom panel and the cover panel are spaced in a thickness direction of the body and the load-bearing sails rise in the direction of thickness such that the fastening strips each extend within a groove of the cover panel;

- Filling a plurality of compartments formed between the carrier webs with a heat insulating lining;

- attach the load-bearing sails to the bottom panel and the cover panel.

According to embodiments, a method of manufacturing a self-supporting body may comprise one or more of the following features: the supporting webs are made by forming a composite material comprising a fiber-reinforced thermoplastic matrix and the fastening strips are taken in the mass of the carrier sails, during their forming.

a step of manufacturing a wearing sail comprises:

o the provision, in a mold, of a composite material comprising a thermoplastic matrix reinforced with fibers;

o the insertion of strips of fasteners, for anchoring a welding support for welding metal strakes of a sealed membrane, inside the mold; o the forming of the composite material during which the fastening strips are taken in the mass of said carrier web, the forming of the composite material is achieved by thermoforming or thermocompression.

According to other embodiments, a method of manufacturing a self-supporting body may comprise one or more of the following features:

a carrier web has a main body having an upper end provided with a housing and an insert comprising thermoplastic material overmolded on a fastening strip, said insert being positioned in the housing of the upper end of the main body of the carrier web and attached to said main body by a thermoplastic welding operation.

a step of manufacturing a wearing sail comprises:

forming a main carrier body having an upper end provided with a housing;

o forming an insert by overmoulding thermoplastic material on a fastening strip;

o positioning said insert in the housing of the main carrier body and fixing said insert on the main body by a thermoplastic welding operation.

The invention also relates to a self-supporting body having such carrier webs having an upper end, for supporting a cover panel, provided with a fastening strip for anchoring a welding support for welding metal strakes a waterproof membrane.

According to one embodiment, the invention also provides a sealed and thermally insulating tank for storing a fluid comprising a thermal insulation barrier comprising a plurality of aforementioned boxes, juxtaposed, and a sealing membrane resting against the barrier. 'thermal insulation.

Such a tank can be part of an onshore storage facility, for example to store LNG or be installed in a floating structure, coastal or deepwater, including a LNG carrier, a floating unit of Storage and Regasification (FSRU), a floating production and remote storage unit (FPSO) and others.

According to one embodiment, a vessel for transporting a fluid comprises a double hull and a said tank disposed in the double hull.

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

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

Brief description of the figures

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.

· Figure 1 is a perspective view, cut away, of a vessel wall according to one embodiment.

• Figure 2 is a top view, cut away of an insulating box of the tank wall of Figure 1.

• Figure 3 is a side view of a carrier web.

FIG. 4 is a sectional view along the plane IV-IV of FIG. 3.

• Figures 5 and 6 illustrate the steps of manufacturing a carrier web according to one embodiment.

• Figure 7 is a schematic sectional view of a self-supporting body according to a first embodiment. • Figure 8 is a schematic sectional view of a self-supporting body according to a second embodiment.

• Figure 9 is a schematic sectional view of a self-supporting body according to a third embodiment.

"Figure 10 is a detailed view of the assembly between a carrier web and bottom panel according to a fourth embodiment.

FIG. 11 is a sectional view of a cover panel and a carrier web, according to one embodiment, equipped with a fastening strip cooperating with a welding support for welding metal strakes of a waterproof membrane.

FIG. 12 is a perspective view illustrating the carrier web and the fastening strip according to the embodiment of FIG. 12.

FIG. 13 is a sectional view of a cover panel and a carrying web, according to another embodiment, equipped with a fastening strip designed to cooperate with a welding support for welding metal strakes. a waterproof membrane.

FIG. 14 is a perspective view illustrating the carrier web and the fastening strip according to the embodiment of FIG. 13.

• Figure 15 is a schematic cutaway representation of a tank LNG tank and a loading / unloading terminal of the tank.

Detailed description of embodiments

In Figure 1, a wall of a sealed and thermally insulating tank is shown. The general structure of such a tank is well known and has a polyhedral shape. It will therefore focus only to describe a wall zone of the tank, it being understood that all the walls of the tank may have a similar general structure.

The wall of the tank comprises, from the outside to the inside of the tank, a supporting structure 1, a secondary heat-insulating barrier 2 which is formed of heat-insulating boxes 3 juxtaposed on the supporting structure 1 and anchored thereto by secondary retaining members 4, a waterproofing membrane secondary 5 carried by the boxes 3, a primary heat-insulating barrier 6 formed of heat-insulating boxes 7 juxtaposed and anchored to the secondary sealing membrane 5 by primary retaining members 8 and a primary sealing membrane 9, carried by the boxes 7 and intended to be in contact with the cryogenic fluid contained in the tank.

The supporting structure 1 may in particular be a self-supporting metal sheet or, more generally, any type of rigid partition having suitable mechanical properties. The supporting structure may in particular be formed by the hull or the double hull of a ship. The carrying structure comprises a plurality of walls defining the general shape of the tank.

The primary 9 and secondary 5 waterproofing membranes are, for example, constituted by a continuous sheet of metal strakes with raised edges, said strakes being welded by their raised edges to parallel welding supports held on the boxes 3, 7. The metal strakes are, for example, made of Invar ®: that is to say an alloy of iron and nickel whose expansion coefficient is typically between 1, 2.10 ^"6 and 2.10 ^{" 6} K ^"1 .

The boxes 3 of the secondary thermally insulating barrier 2 and the boxes 7 of the primary thermally insulating barrier 6 can equally well have identical or different structures and equal or different dimensions.

Referring to Figure 2, we describe the general structure of a box 3, 7 of the secondary thermally insulating barrier 2 and / or the primary thermally insulating barrier 6. The box 3, 7 has substantially a rectangular parallelepiped shape. The box 3, 7 has a bottom panel 10 and a cover panel 11 parallel. The bottom panels 10 and cover 11 are, for example, made of plywood.

A plurality of spacers are interposed between the bottom panel 10 and the cover panel 1-1, perpendicular to them. The plurality of spacer elements comprises, on the one hand, two opposite lateral walls 12, 13, and, on the other hand, a plurality of carrying webs 14. The carrying webs 14 are arranged parallel to each other between the two side walls 12, 13, in a direction perpendicular to said side walls 12, 13. The carrier webs 14 rise in the thickness direction of the body 3, 7. In one embodiment, the cover panel 11 has, on its inner face, grooves for the housing of the welding supports metal strakes of waterproofing membrane. In other embodiments, which will be described hereinafter with reference to FIGS. 11 to 14, the welding supports 31 are held by fastening strips 30 integral with the load-bearing webs 14 of the boxes 3, 7 and the cover panel. 1 1 cover has through grooves 32 for hanging the welding supports 31 to the fastening strips 30.

Compartments 15 for accommodating a heat-insulating lining are provided between the supporting webs 14. The heat-insulating lining may be made of any material having appropriate thermal insulation properties. By way of example, the heat-insulating lining is chosen from materials such as perlite, glass wool, polyurethane foam, polyethylene foam, polyvinyl chloride foam, aerogels or others.

The carrier webs 14 are wavy and oscillate on either side of their longitudinal general direction. Each corrugation thus extends along an axis perpendicular to the bottom panels 10 and cover 11. In the embodiment shown, the corrugations are substantially sinusoidal. However, other forms of undulations are also possible. For example, the corrugations may in particular have shapes of triangular teeth or rectangular crenellations. Due to their shape, such corrugated carrier webs 14 have a high buckling resistance without the need to give them much thickness. It should be noted that if corrugations having a periodic structure make it possible to ensure good uniformity of the compressive strength, it is also possible to provide non-periodic corrugations in order to meet certain localized mechanical requirements.

Figures 3 and 4 illustrate a carrier web 14. Along its edges extending opposite the bottom panel 10 and the cover panel 11, the carrier web 14 has flanges 16a, 16b distribution of loads. The upper flange 16a has a flat surface intended to face the cover panel 1 1 while the lower flange 16b has a flat surface which is intended to face the bottom panel 10. The flanges 16a, 16b have a width which is greater than the thickness of the wall of the carrier web 14 in its main part, extending between the two flanges 16a, 16b. Thus, the load distribution flanges 16a, 16b prevent stress concentration on a particular area by providing a greater bearing surface between the carrier web 14 and the bottom panels 10 and cover 11. The flanges 16a, 16b load distribution may have a parallelepiped shape, as shown in Figures 3 or 4. In this case, the width of the flanges 16a, 16b may be equal to the amplitude of the corrugations. In other embodiments, the load distribution flanges 16a, 16b may themselves have corrugations.

The carrier webs 14 are made of composite material comprising a thermoplastic matrix reinforced with fibers. A method of manufacturing the carrier webs 14 is described in connection with FIGS. 5 and 6.

In a first phase, as shown in FIG. 5, an intermediate product is produced in the form of composite material plates. For this purpose, a double-band press 17 is supplied with fiberglass 18 and thermoplastic resin 19, for example polypropylene-based. The thermoplastic resin 19 can be loaded on the double-band press 17 in the form of extruded films or in powder form. The glass fibers 18 are provided as coils of glass yarn, cut to the desired length. The thermoplastic resin 19 and the glass fibers 18 are co-laminated in the double-web press 17. At the outlet of the double-band press 17, a cutting device makes it possible to obtain a plurality of plates.

Such plates have a composite structure comprising a thermoplastic matrix and a mat or fiberglass felt. Such composite structures are designated by the acronym GMT, for "glass fiber mat reinforced thermoplastics" in English.

In a second step, the plates of composite material are shaped, as shown in FIG. 5. To do this, the plates of composite material are heated in an oven 20, then placed in a mold 21 in which they are going to be shaped by applying pressure. The carrier webs 14 thus formed are then cooled. The carrier webs 14 are thus shaped by thermocompression, by heating the composite material plates and then stamping them on the press. In another embodiment, the carrier webs 14 can also be made by thermoforming, that is to say by creep of the composite material plates under temperature conditions and under vacuum.

We note that the method of producing a carrier web 14 is described above only by way of example and that the invention is not limited to carrier webs 14 thus produced. In particular, the carrier webs 14 can also be obtained by injection molding, extrusion or pultrusion. In addition, the thermoplastic matrix may comprise any suitable thermoplastic material, such as polypropylene (PP), polyethylene (PE), polyamides (PA), polyetherimide (PEI), polyvinyl chloride (PVC), poly (terephthalate) ethylene (PET), polybutylene terephthalate (PBT), acrylonitrile-butadiene-styrene copolymer (ABS), etc. It is also possible to reinforce the thermoplastic matrix with carbon fibers or with a mixture of fibers. carbon and fiberglass.

Figure 7 illustrates the assembly of carrier webs 14 and bottom panels 10 and cover 11 according to one embodiment. The bottom panels 10 and cover 11 have a plywood body. The inner faces of the bottom panels 10 and the lid 11, turned towards the inside of the body, are covered with thermoplastic film 21, 22. In order to allow the attachment of the load-bearing webs to the panels 10, 11, an plastic welding operation in the interface areas 25 between the thermoplastic films 21, 22 and the carrier webs 14 of composite material.

The welding operation is, for example, carried out by infrared radiation. However, it is possible to use any other suitable plastic welding method, such as ultrasonic welding, induction heating, friction welding, fusion welding, hot air jet welding or the flaming. Note that in the case of induction welding, it is necessary to have the metal inserts on the carrier webs and / or on the bottom panels 10 and / or cover 11, at the interface between the carrier webs 14 and the bottom panels 0 and lid 11 so as to allow heating of the thermoplastic material.

In one embodiment, before welding operations, protective masks are previously arranged on the inner faces of the bottom panels 10 and cover 11 between the interface areas. Between the carrier webs 14 and the panels 10, 11. When the welding operations have been performed, the protective masks can then be removed. Thus, the thermoplastic films 21, 22 are not deteriorated during welding operations. Such protective masks are, for example, made of metal, ceramic and / or glass materials. Such masks are advantageously equipped with a cooling circuit in which a fluid circulates, such as water, air or oil in order to regulate the temperature of said masks.

In the embodiment shown, the outer face of the bottom panels 10 and lid 11 is also covered with thermoplastic films

23, 24. Such an arrangement makes it possible to balance the bending of the cover panels 11 and the bottom panels 10, in particular when they are under considerable thermal stress when the tank is cold.

In the embodiment shown in FIG. 8, the thermoplastic films 21, 22 only partly cover the inner faces of the bottom panels 10 and the cover panels 11. In this case, strips 29 of thermoplastic films are arranged in the zones interface 25 with the carrier webs 14.

The thermoplastic films 21, 22, 23, 24, 29 are for example made of a composite material comprising a thermoplastic matrix reinforced with fibers. Thus, such thermoplastic films 21, 22, 23, 24, 29 contribute to increasing the mechanical strength of the bottom and cover panels, increasing their bending stiffness and improving their punching resistance. Such thermoplastic films 21, 22, 23, 24, 29 typically have a thickness of the order of 0.5 to 5 mm.

In one embodiment, the thermoplastic films 21, 22, 23, 24, 29 are attached to the body of the bottom and cover panels 11 by gluing. The glue used is for example an acrylic glue, a polyurethane glue, or an epoxy glue.

In another embodiment, the thermoplastic films 21, 22, 23,

24, 29 are fixed to the body of the panels by a hot pressing process. In such a case, it is conceivable to integrate the fixing of the thermoplastic films directly to the plywood manufacturing process. To do this, we superimposed wood plies, previously glued, and thermoplastic films, then subjecting the stack thus obtained to a hot pressing. For example, for such a hot pressing, the or subjecting the stack to a temperature of the order of 190 to 200 ° C and a pressure of the order of 0.2 MPa for a period of 5 minutes.

In order to facilitate the welding operations, the thermoplastic films 21, 22, 23, 24, 29 comprise a thermoplastic matrix identical to the thermoplastic matrix of the carrier webs 14.

In the embodiment shown in FIG. 9, it is the body of the bottom panels 10 and the cover 11, as such, which forms the thermoplastic element for fastening the carrier webs 14. According to a first variant, the bottom panels 10 and cover 11 comprise a body made of a composite material comprising a thermoplastic matrix, identical to that of the carrier webs 14, reinforced by fibers.

According to a second variant, the bottom panels 10 and lid 11 are made of a wooden body, impregnated with a thermoplastic matrix, of the same nature as that of the carrier webs. The body may be manufactured by agglomeration of previously impregnated fibers. a thermoplastic matrix. Alternatively, the body may be made of plywood whose inner ply, and optionally the outer ply, are made of a wood sufficiently porous to diffuse the plastic matrix hot and under pressure within said plies. Such wood is for example selected from birch, fir, beech or others.

Figure 10 shows the assembly of carrier webs 14 and bottom panels 10 and cover 11 according to another embodiment. In this embodiment, the bottom panels 10 and cover 10 have, in their interface areas 25 with the carrier webs 14, through bores, through which are inserted thermoplastic pins 26. The thermoplastic pins 26 are equipped of heads 27 resting against the outer face of the bottom panels 10 and cover 11 and distal ends 28 extending inside bores formed in the edges of the carrier webs 14. The welding of the thermoplastic pins 26 to the the interior of the bores formed in the load-bearing sails 14 makes it possible to secure the load-bearing sails 14 to the In one embodiment, the welding operations are carried out by friction by driving the thermoplastic pins 26 in rotation. The movement of the thermoplastic pins 26 with respect to the load-bearing webs 14 leads to a heating of the interface up to 50.degree. to local plasticization of the thermoplastic material and welding.

The positioning of the heat-insulating lining in the compartments 15 formed between the load-bearing webs 14 can be done after the fixing of the load-bearing sails 14 on the cover panels 11 and bottom panels 10. However, the order in which this step is carried out is indifferent. In particular, it is also possible to pre-assemble the heat-insulating packing and the carrying sails 14 and then to fix the carrying sails 14 to the bottom panels 10 and the cover 11. In another embodiment, it is also possible to fix the carrier webs 14 to one of the bottom panels 10 or cover 11, to fill the compartments 15 formed between the carrier webs 14, for example by foam projection, then to close the self-supporting body by fixing the other of the panels of bottom 10 or cover 11 on the carrier webs 14.

In the embodiment illustrated in FIGS. 11 and 12, the carrier web 14 has at its upper end a fastening strip 30 for holding a solder support 31, illustrated only in FIG. 11, for welding metal strakes. a waterproof membrane. The cover panel 11, illustrated in FIG. 11, has a plurality of grooves 32 coming opposite the upper ends of the supporting webs 14. The fastening strips 30 thus extend inside the grooves 32. in order to allow the attachment of the welding supports 31 to the fastening strips 32. The welding support 31 and the fastening strip 30 are both made of invar ® sheet and constitute a sliding seal. To do this, the fastening strip 30 has a longitudinal edge folded U to form a hook 33. Similarly, the solder support 31 has a longitudinal border folded U to form a hook 34. The two hooks 33, 34 are fitted into each other so that the welding support 31 is retained on the carrier web 14 by means of the fastening strip 30. A sliding joint thus formed allows a sliding of the welding support 31 relative to at self-supporting box 3, 7 in the longitudinal direction. In FIGS. 11 and 12, the fastening strip 30 is integrated in an insert 35 made by overmolding thermoplastic material on the fastening strip 30. The strip fixing device 30 comprises an anchoring wing 36 extending substantially perpendicular to the direction of thickness of the body 3, 7 self-supporting and to ensure a strong anchoring of the fastening strip 30 in the insert 35. insert 35 is positioned in a housing formed at the upper sole 16a of load distribution and then fixed on the main body of the carrier web 14 by heat sealing. The heat sealing operation can be carried out by any one of the welding methods described above. Such integration of the fastening strip 30 in the carrier web 14 avoids the need for staples, which can degrade the structure of the carrier webs 14 causing cracks. In addition, such integration via an insert of thermoplastic material heat-sealed on the main body of the carrier web 14 facilitates the production and demolding of the carrier web 14.

In another embodiment detailed in Figures 13 and 14, the fastening strip 30 is taken in the mass of the carrier web 14, during its thermoforming. The fastening strip also has an anchoring wing 36 extending substantially perpendicular to the direction of thickness of the body 3, 7. The fastening strip 30 is disposed inside the mold 21 and is embedded in the mass of the carrier web 14 during its thermoforming. Such integration of the fastening strip 30 in the carrier web 14 is simple.

The technique described above for producing a self-supporting box can be used in different types of tanks, for example to produce the primary thermal insulation barrier and / or the secondary thermal insulation barrier of an LNG tank in an installation. land or in a floating structure such as a LNG tanker or other.

Referring to Figure 15, a cutaway view of a LNG tank 70 shows a sealed and insulated tank 71 of general prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary sealed barrier intended to be in contact with the LNG contained in the tank, a secondary sealed barrier arranged between the primary waterproof barrier and the double hull 72 of the ship, and two thermal insulation barriers arranged respectively between the primary watertight barrier and the secondary watertight barrier and between the secondary watertight barrier 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.

FIG. 15 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 a fixed off-shore installation comprising an arm mobile 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 of LNG carriers . A connection pipe (not shown) extends inside the tower 78. The loading and unloading station 75 enables the loading and unloading of the LNG tank 70 from or to the shore facility 77. liquefied gas storage tanks 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 onshore installation 77 over a large distance, for example 5 km, which makes it possible to keep the tanker vessel 70 at 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.

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 could be construed as a limitation of the claim.

Claims

1. A method of manufacturing a self-supporting body (3, 7) intended for the thermal insulation of a tank, with a sealed membrane, for storing a fluid, said method comprising:

providing a plurality of carrier webs (14) made of a composite material comprising a fiber-reinforced thermoplastic matrix;

providing a bottom panel (10) and a cover panel (1 1);

interposing the carrier webs (14) between the bottom panel (10) and the cover panel (11), so that the bottom panel (10) and the cover panel (1 1) are spaced in a direction d the thickness of the box (3, 7) and that the carrier webs (14) rise in the direction of thickness;

attaching the carrier webs (14) to the bottom panel (10) and the cover panel (1 1);

filling a plurality of compartments (15) formed between the carrier webs (14) with a heat insulating lining;

wherein the bottom panel (10) and the cover panel (11) each comprise at least one thermoplastic element (21, 22, 26, 29) for attaching the carrier webs (14); and wherein the carrier webs (14) are attached to the bottom panel and the cover panel by a thermoplastic welding operation performed at the interface areas (25) between the carrier webs (14) and the thermoplastic elements (21). , 22, 26, 29) of the bottom panel (10) and the cover panel (1 1).

2. Manufacturing method according to claim 1, wherein the bottom panel (10) and the cover panel (1 1) each have an inner face facing the inside of the body and an outer face, the inner faces of the bottom panel (10) and cover panel (1 1) being coated with thermoplastic film (21, 22, 29) for fixing the carrier webs (14).

3. Manufacturing method according to claim 2, wherein the inner face of the bottom panel (10) and / or the cover panel (11) is integrally coated with thermoplastic film (21, 22).

4. Manufacturing method according to claim 3 comprising a step of disposing removable protective masks on the inner face of the panel bottom (10) and / or cover (11) between the interface areas (25) prior to the welding operation.

5. The manufacturing method according to claim 3 or 4, wherein the outer face of the bottom panel (10) and / or the cover panel (1 1) is also coated with thermoplastic film (23, 24).

The manufacturing method according to claim 2, wherein the inner face of the bottom panel (10) and / or the cover panel (11) is partially coated with thermoplastic film, a plurality of strips (29) of thermoplastic film being each disposed in an interface zone (25) with a carrier web (14).

The manufacturing method according to any one of claims 2 to 6, wherein the bottom panel (10) and / or the cover panel (11) comprises a plywood body and wherein the thermoplastic film (21, 22, 29) is glued to the plywood body or assembled to the body by hot pressing.

8. Manufacturing process according to any one of claims 2 to 7, wherein the thermoplastic film (21, 22, 23, 24) is a composite material comprising a thermoplastic matrix reinforced with fibers.

9. The manufacturing method according to claim 1, wherein the bottom panel (10) and / or the cover panel (11) comprises a body made of a composite material comprising a thermoplastic matrix reinforced with fibers, said body forming a thermoplastic element for fixing the carrier webs (14).

10. The manufacturing method according to claim 1, wherein the bottom panel (10) and / or the cover panel (11) comprises a wooden body impregnated with a thermoplastic matrix for fixing the carrier webs, said body forming a thermoplastic element for fixing the carrier webs (14).

11. The manufacturing method according to claim 1, wherein the thermoplastic elements are thermoplastic pins (26) inserted inside bores formed in the bottom panels (10) and / or cover (11) and in interior of bores formed in the load-bearing sails (14).

12. Manufacturing process according to any one of claims 1 to 1 1, wherein the thermoplastic elements for fixing the carrier sails. comprise a thermoplastic matrix identical to the thermoplastic matrix of the carrier webs (14).

13. The manufacturing method according to any one of claims 1 to 12, wherein the thermoplastic welding is performed by a method selected from infrared radiation welding, ultrasonic welding, induction heating, friction welding, fusion welding, hot air jet welding and flaming.

14. The manufacturing method according to any one of claims 1 to 13, wherein:

- the carrier webs (14) have an upper end for supporting a cover panel, provided with a fastening strip (30) for anchoring a welding support (31) for welding metal strakes a waterproof membrane (5, 9) intended to rest against the self-supporting body (3, 7), said fastening strip (30) having a folded longitudinal edge (33) intended to cooperate with a folded longitudinal edge (34) solder support (31);

the cover panel (11) has parallel grooves (32) extending over the entire thickness of the cover panel;

the carrier webs (14) are arranged between the bottom panel (10) and the cover panel (1 1) so that the fastening strips (30) each extend inside a groove (32) of the cover panel (11).

15. The manufacturing method according to claim 14, wherein the fastening strips (30) are made in the mass of the carrier webs (14), during their forming.

16. The manufacturing method according to claim 14, wherein a carrier web (14) comprises a main body having an upper end provided with a housing and an insert (35) comprising thermoplastic material overmolded onto a fastening strip (30). ), said insert (35) being positioned in the housing of the upper end of the main body of the carrier web (14) and attached to said main body by a thermoplastic welding operation.

17. Self-supporting box (3, 7) for the thermal insulation of a tank, with a sealed membrane, for storing a fluid, said box (3, 7) comprising: a bottom panel (10) and a cover panel (11) spaced in a thickness direction of the box (3, 7);

a plurality of carrier webs (14), interposed between said bottom (10) and cover (1 1) panels, and extending in the thickness direction to define a plurality of compartments (15), said sails carriers

(14) being made of a composite material comprising a thermoplastic matrix reinforced with fibers; and

a heat insulating lining extending within said compartments (15) formed between the carrier webs (14);

in which :

the bottom panel (10) and the cover panel (11) each comprise at least one thermoplastic element (21, 22, 26); and

the carrier webs (14) are fixed to the bottom panel (10) and to the cover panel (11) by thermoplastic welding in interface areas (25) between the carrier webs (14) and the thermoplastic elements (21). , 22, 26) of the bottom panel (10) and the cover panel (11).

18. Case (3, 7) according to claim 17, wherein the carrier webs (14) have load distribution flanges (16a, 16b) extending along two edges of said carrier webs (14) respectively disposed in vis-à-vis the bottom panel (10) and the cover panel (10).

19. Box (3, 7) according to claim 17 or 18, wherein the carrier webs (14) have a plurality of corrugations whose axis extends perpendicularly to the bottom panels (10) and cover (11). .

20. A sealed and thermally insulating storage tank for a fluid comprising a thermal insulation barrier (2, 6) comprising a plurality of boxes (3, 7) according to any one of claims 17 to 19, juxtaposed, and a sealing membrane (5, 9) resting against the thermal insulation barrier.

21. Vessel (70) for the transport of a fluid, the vessel having a double hull (72) and a tank (71) according to claim 20 disposed in the double hull.

A method of loading or unloading a vessel (70) according to claim 21, wherein a fluid is conveyed through pipelines. isolated (73, 79, 76, 81) from or to a floating or land storage facility (77) to or from the vessel (71).

23. Transfer system for a fluid, the system comprising a ship (70) according to claim 21, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) installed in the hull of the ship. at a floating or land storage facility (77) and a pump for driving fluid through the insulated pipelines from or to the floating or land storage facility to or from the vessel vessel.