FR3110952A1 - Self-supporting body suitable for the support and thermal insulation of a waterproof membrane - Google Patents

Abstract

A self-supporting box has at least one groove (30) in the cover panel and opening on an upper surface of the cover panel to receive a welding support. At least one load-bearing partition (26) extends longitudinally above the groove (30). Fasteners (35) perpendicularly engaged in the bottom plate (22) and the top surface of the load-bearing partition (26) fasten the load-bearing partition to the cover panel. The upper surface of the load-bearing partition (26) is wider than the bottom part (32) of the groove (30) and the clips (35) are engaged in an area of the lower plate (22) offset laterally with respect to the bottom part (32) of the groove. The primary insulating barrier of a tank essentially consists of boxes filled with a thermal insulation. The primary waterproof membrane is retained on the cover panels by weld brackets inserted into the grooves (30). Fig. 3

Description

Self-supporting box suitable for the support and thermal insulation of a waterproof membrane

The invention relates to the field of sealed and thermally insulating tanks integrated into a supporting structure to contain a fluid, in particular to membrane tanks to contain liquefied gases, in particular combustible gases. In particular, the invention also relates to self-supporting wooden boxes suitable for supporting and thermally insulating the membranes of such tanks.

Sealed and thermally insulating tanks can be used in different industries to store fluids. For example, in the field of energy, liquefied natural gas (LNG) is a liquid with a high methane content that can be stored at atmospheric pressure at approximately -163°C in onshore storage tanks or in onboard tanks. in floating structures. Liquefied Petroleum Gas (LPG) can be stored at a temperature between -50°C and 0°C.

In the case of a floating structure, the tank may be intended for the transport of liquefied gas or to receive liquefied gas used as fuel for the propulsion of the floating structure.

We know, for example in FR-A-2867831, a self-supporting wooden box suitable for the support and thermal insulation of a sealed membrane intended to contain a fluid, the box comprising:
a back panel,
side sails fixed to the bottom panel and projecting perpendicularly from one side of the bottom panel to delimit the contour of an interior space of the body,
a cover panel supported and fixed on an upper edge of the side panels parallel to the bottom panel and at a distance from the bottom panel to close the interior space of the box, the cover panel comprising a top plate and a bottom plate superimposed and attached to each other,
at least one groove formed in the cover panel and opening onto an upper surface of the cover panel to receive a welding support intended to retain a waterproof membrane on the cover panel,
at least one load-bearing partition extending longitudinally in line with the or each groove parallel to the groove, the load-bearing partition being arranged perpendicular to the bottom panel and to the cover panel, the load-bearing partition extending between the said side walls of so as to divide the interior space into a plurality of compartments intended to receive a thermal insulation, the load-bearing partition having an upper surface in contact with the lower plate of the cover panel and a lower surface in contact with the bottom panel,
and fasteners perpendicularly engaged in the bottom plate and the top surface of the load-bearing bulkhead to attach the load-bearing bulkhead to the cover panel.

In FR-A-2867831 this self-supporting box is used to produce a primary thermally insulating barrier supporting a primary waterproof membrane. The primary waterproof membrane is welded to a weld backing which forms a slip joint with a tack strip stapled into the groove. For this, the longitudinal groove passes through the two boards of the cover panel and the upper part of the underlying load-bearing partition between two rows of staples.

It is also known, for example in FR-A-2867831 or WO-A-8909909, to use a secondary self-supporting box which comprises a simple grooved cover plate with grooves having a T-shaped section to receive a support of welding in the form of a wing bent at a right angle. In FR-A-2867831, there is no load-bearing partition directly above the groove. In WO-A-8909909, the cover plate is fixed to an underlying load-bearing partition by screws housed in the bottom of the groove.

An object of the invention is to provide a resistant self-supporting box to be able to be used to produce a primary insulating barrier in a tank, likely to be subjected to dynamic pressures and impacts due to the sloshing of the cargo. Another object of the invention is to allow the use of a welding support in the form of a wing bent at right angles also in a primary waterproof membrane, for example with a view to simplifying or standardizing manufacturing and reduce parts inventory.

For this, the invention provides a self-supporting case mentioned above, characterized in that the groove has a section comprising, successively in a direction of thickness of the upper plate, a wider bottom part and a narrower mouth part. ,
and that the upper surface of the load-bearing partition is wider than the bottom part of the groove, the fasteners being engaged in an area of the lower plate offset laterally with respect to the bottom part of the groove.

Thanks to these characteristics, the fasteners engaged in the lower plate to attach the load-bearing partition to the cover panel do not weaken the cover panel directly above the groove. This arrangement therefore makes it possible to reliably fix the load-bearing partition while having an increased mechanical resistance of the cover panel compared to a box of the prior art.

According to embodiments, such a self-supporting crate may include one or more of the following arrangements.

Preferably, the groove is made only in the top plate of the cover panel.

Preferably, the clips attach the load-bearing bulkhead to the cover panel independently of the top plate. Thus, the upper plate of the cover panel is not weakened by the presence of the fasteners.

According to one embodiment, the groove has a T-shaped section, in which the bottom part of the groove corresponds to the horizontal bar of the T and the mouth part corresponds to the vertical bar of the T.

According to one embodiment, the bottom part of the groove has a width of between 20 and 30 mm.

According to one embodiment, a difference between the width of the bottom part of the groove and the width of the upper surface of the supporting partition is greater than 10 mm.

According to one embodiment, a median line of the bottom part of the groove is located plumb with a median plane of the load-bearing partition.

According to one embodiment, the fasteners are arranged on either side of a median plane of the load-bearing partition.

According to one embodiment, the load-bearing partition is made of wood, plywood or composite.

According to one embodiment, the supporting partition has a uniform width wider than the bottom part of the groove.

According to another embodiment, the internal partition has an upper flange arranged parallel against the lower plate and a central portion arranged under the upper flange, the upper flange being wider than the bottom part of the groove, the central portion having a width equal to or narrower than the bottom portion of the groove.

According to one embodiment, the load-bearing partition has a multilayer structure in a width direction, the multilayer structure comprising a core of insulating material and two side plates that are more rigid than the insulating material, the fasteners being engaged in the side plates. For example, the insulating material is selected from polymer foams, in particular polyurethane foam, mineral fibers, in particular glass wool, wadding and expanded polystyrene.

According to one embodiment, two parallel grooves are made in the cover panel and a respective internal partition extends directly above each groove.

According to one embodiment, the body has the general shape of a rectangular parallelepiped.

According to one embodiment, the invention also provides a sealed and thermally insulating tank for storing a fluid, said tank comprising a tank wall fixed to a supporting wall,
wherein the vessel wall comprises, in the thickness direction from the exterior to the interior of said vessel, a secondary insulating barrier retained on said load-bearing wall, a secondary waterproof membrane retained on said secondary insulating barrier, a barrier primary insulating barrier retained on the said secondary waterproof membrane and a primary waterproof membrane retained on the said primary insulating barrier, characterized in that the said primary insulating barrier consists essentially of the aforementioned boxes, juxtaposed and filled with a heat-insulating gasket, the primary waterproof membrane being retained on the cover panels of said boxes by welding supports inserted in said grooves.

According to one embodiment, the fluid is a liquefied gas, such as liquefied natural gas, liquefied petroleum gas, liquefied ethylene.

Such a tank can be part of an onshore storage facility, a storage facility placed on the seabed, for example to store LNG, or be installed in a floating, coastal or deep-water structure, in particular an LNG carrier, a floating storage and regasification unit (FSRU), 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 aforementioned tank placed in the double hull. According to one embodiment, the double shell comprises an inner shell forming the carrier wall of the tank.

According to one embodiment, the invention also provides a method for loading or unloading such a ship, in which a fluid is routed through insulated pipes from or to a floating or terrestrial storage installation to or from the tank of the ship.

According to one embodiment, the invention also provides a transfer system for a fluid, the system comprising the aforementioned vessel, insulated pipes arranged so as to connect the tank installed in the hull of the vessel to a floating or terrestrial storage installation and a pump for driving a fluid through the insulated pipes from or to the floating or terrestrial storage installation to or from the tank of the ship.

The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation. , with reference to the accompanying drawings.

Figure 1 is a cutaway perspective view of a sealed and thermally insulating vessel wall in which self-supporting boxes can be used.

Figure 2 is a side view of a self-supporting box suitable for a primary insulating barrier of the vessel wall of FIG. 1.

[Fig.3-5] Figures 3 to 5 are enlarged views of Zone III of Fig. 2 illustrating three embodiments of a load-bearing partition.

FIG. 6 is a cutaway schematic representation of an LNG carrier tank and a loading/unloading terminal for this tank.

The general structure of a vessel wall 1, sealed and thermally insulating, integrated and anchored to a load-bearing wall 2, is illustrated in FIG. 1. The vessel wall 1 can be part of a vessel having different geometries, for example a polyhedral shape. Fig. 1 shows the vessel wall 1 seen in perspective from above with a cutaway to show the structure of this wall. Such a structure can be implemented on extended surfaces having various orientations, for example to cover bottom, ceiling and side walls of a polyhedral tank. The orientation of Fig. 1 is therefore not limiting in this respect. By convention, we will call "above" a position located closer to the inside of the tank and "below" a position located closer to the bearing wall 2, regardless of the orientation of the vessel wall with respect to to the earth's gravity field.

The vessel wall 1 is composed successively in its thickness of a secondary insulating barrier 3 which is formed of boxes juxtaposed on the carrier wall 2 and retained thereon by secondary retaining members; then a secondary waterproof membrane 4 carried by a secondary insulating barrier 3; then a primary insulating barrier formed of boxes 5 juxtaposed and retained on the secondary sealed membrane 4 by primary retaining members themselves fixed to the secondary retaining members 4 and, finally, a primary sealed membrane 6 carried by the boxes 5. Secondary and primary retainers are for example described in FR-A-2798902.

The primary waterproof membrane 6 may consist of a continuous sheet of steel strakes 10 with a high nickel content, for example 37%, known as invar, whose expansion coefficient is typically between 1.2.10 ^{- 6} and 2.10 ^-6 K ^-1 . It is also possible to use alloys of iron and manganese whose coefficient of expansion is typically of the order of 7 to 9.10 ^-6 K ^-1 . The strakes 10 are welded in a sealed manner by their raised side edges to parallel weld supports 8 retained in the grooves of the cover panels 7 of the boxes 5. The secondary waterproof membrane 4 can be made identically, as illustrated in FIG. 1, or differently. The number 9 designates a groove to receive a welding support of the secondary waterproof membrane 4.

The box 5 partially visible in FIG. 1 has an overall parallelepipedic shape. Fig. 2 shows a side plan view along the arrow II of FIG. 1.

With reference to FIG. 2, a lower plate 22 and an upper plate 21 fixed rigidly to each other, for example by screwing, gluing and/or stapling, together constitute the cover plate. The attachment of the upper 21 and lower 22 plates to each other is carried out for example on the periphery of the load-bearing partitions 26, 126 or 226 and plumb with the secondary partitions 25 while securing the upper 21 and lower 22 plates with the secondary partitions 25. The bottom panel 23 and cover panel 7 have a rectangular outline and are spaced from each other by two longitudinal end webs 27 and two lateral end webs 24 together forming the outline of the interior space of the body 5. This interior space is compartmentalized by two load-bearing partitions 26 located directly above the grooves 30 and possibly secondary partitions 25 which may be narrower than the load-bearing partitions 26. The load-bearing partitions 26 and secondary partitions 25 extend longitudinally perpendicular to the two longitudinal end sails 27 and parallel to the two lateral end sails 24. All these elements are f fixed as necessary by stapling, screwing and/or gluing. By way of example, the secondary partitions 25 have a width of 12 mm and the longitudinal 27 and lateral 24 end webs have a width of between 12 and 24 mm.

To perform the function of thermal insulation of the box 5, the compartments are filled with a heat-insulating lining, for example in a material chosen from among expanded perlite, airgel materials in a particulate or fibrous form, expanded polystyrene, wool glass, cellulose wadding, low density polymer foams, for example polyethylene, polyurethane or others.

The dimensions of the box 5 can of course be different from the example shown in Figure 2. In its width, the box 5 has a single load-bearing partition 26 and a single groove 30 or, on the contrary, a number of load-bearing partitions 26 and grooves 30 higher than two.

As best seen in Fig. 3, the groove 30 has an inverted T-shaped section, comprising a horizontal and wide bottom part 32 and a vertical and narrow mouth part 31, in order to receive a welding wing bent at right angles, according to the known technique . Alternatively, the bottom part 32 could extend from one side only of the mouth part, so that the groove has an L-shaped section.

The load-bearing partition 26 is a plywood plate which has a width W greater than the width of the bottom part 32. This extra width makes it possible to place rows of staples 35 offset laterally with respect to the bottom part 32 , that is to say outside the zone located directly above the groove 30, to fix the load-bearing partition 26 to the lower plate 22. This arrangement makes it possible to preserve the rigidity of the cover panel 7 despite the relatively large width of the groove 30, the bottom part 32 of which is for example 24mm wide. Indeed, even if the staples 35 can locally reduce the rigidity of the lower plate 22 of the cover panel, this weakening does not occur at the same place as the thinning resulting from the groove 30. Preferably, the over-width of the load-bearing partition 26 is greater than 10mm. For example the width W is 36 mm or more and preferably 42 mm.

In Fig.3, the rigidity of the cover panel 7 is further improved by the following measures:
- The groove 30 is provided only in the upper plate 21 of the cover panel. Thus, the groove 30 does not affect the rigidity of the bottom plate 22.
- the fasteners 35 do not affect the rigidity of the upper plate 21.
- The carrier partition 26 is centered under the groove 30 and symmetrical with respect to a median plane.
- The fasteners 35 are arranged on either side of the median plane of the load-bearing partition.

Fig. 4 shows another embodiment of the load-bearing partition 126, which has a multilayer structure in the direction of its width, with a core 41 of insulating material and two side plates 42 more rigid than the insulating material on either side of the core 41. The fasteners 35 are engaged in the side plates 42, which are for example made of plywood. This construction makes it possible to limit the weight and the thermal bridge with respect to the load-bearing partition 26. By way of example, the side plates 42 have a width of 12 mm.

Fig. 5 shows another embodiment of the load-bearing partition 226, which has, successively in the thickness direction of the body 5, an upper flange 52 disposed parallel against the lower plate 22 and a central portion 51 disposed under the upper flange 52 The upper sole 52 has the width W greater than the width of the bottom part 32. Conversely, the central portion 51 can be equal to or narrower than the bottom part 32 of the groove 30. The upper sole 52 and the central portion 51 are for example made of plywood. This construction makes it possible to limit the weight and the thermal bridge with respect to the load-bearing partition 26. By way of example, the central portion 51 has a width of between 18 and 30 mm, preferably 24 mm. By way of example, the upper flange 52 has a width greater than 24 mm, for example 42 mm.

Figure 2 also shows other features of the self-supporting box 5, which can be used as needed:
- to circulate an inert gas in the primary insulating barrier, holes 28 are formed in the webs 27 of the body 5.
- A gas-permeable stopper 17, made of fiberglass fabric, is glued in front of each hole 28 on the inner surface of the veil 27 to prevent leakage of the thermal insulation.
- fixing tenons 19 serving as a bearing surface for the primary retaining members are fixed against the sails 27 on the edges of the bottom panel 23.
- a stiffening comb 16 perpendicular to the load-bearing partitions 26 and secondary partitions 25 extends between the webs 24 perpendicular to the bottom panel 23. At its intersection with the load-bearing partitions 26 and secondary partitions 25, it has notches to form a interlocking with the load-bearing partitions 26 and secondary partitions 25.
- grooves 18 made in the bottom panel 23 and the load-bearing partitions 26 make it possible to accommodate the projecting portions of the secondary waterproof membrane 4.

Instead of plywood, composite materials can be used to make all or part of the self-supporting box. For example, suitable composite materials are taught in WO-A-2015079135.

A primary insulating barrier can be constructed with the boxes 5 described above in their entirety or only in certain parts of the vessel. For example, the boxes 5 described above can be used close to the edges of the vessel while other insulating blocks are used in other portions of the vessel walls. Such an arrangement is described for example in WO-A-2019077253.

Referring to Figure 6, a cutaway view of an LNG carrier 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary tight barrier intended to be in contact with the liquefied gas contained in the tank, a secondary tight barrier arranged between the primary tight barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the primary watertight barrier and the secondary watertight barrier and between the secondary watertight barrier and the double hull 72. In a simplified variant, the ship comprises a single hull.

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

FIG. 6 represents an example of a maritime 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 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading/unloading pipes 73. The orientable mobile arm 74 adapts to all sizes of LNG carriers . A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the shore installation 77. This comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75. The underwater pipe 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the shore installation 77 over a great distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a great distance from the coast during loading and unloading operations.

To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and/or pumps fitted to the shore installation 77 and/or pumps fitted to the loading and unloading station 75 are used.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

The use of the verb "to comprise", "to understand" or "to include" and of its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

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

Claims (17)

Self-supporting box (5) suitable for supporting and thermally insulating a sealed membrane (6) intended to contain a fluid, the box (5) comprising:
a bottom panel (23),
side panels (24, 27) fixed to the bottom panel and projecting perpendicularly from one side of the bottom panel to delimit the contour of an interior space of the body,
a cover panel (7) supported and fixed on an upper edge of the side panels parallel to the bottom panel and at a distance from the bottom panel to close the interior space of the box, the cover panel comprising a top plate (21) and a lower plate (22) superposed and fixed to each other,
at least one groove (30) formed in the cover panel and opening onto an upper surface of the cover panel to receive a welding support (8) intended to retain a waterproof membrane (6) on the cover panel,
at least one load-bearing partition (26, 126, 226) extending longitudinally above the groove (30) parallel to the groove, the load-bearing partition being arranged perpendicular to the bottom panel (23) and to the cover panel ( 7), the load-bearing partition extending between the said side walls (27) so as to divide the interior space into a plurality of compartments intended to receive a heat-insulating lining, the load-bearing partition (26, 126, 226) presenting an upper surface in contact with the bottom plate (22) of the cover panel and a bottom surface in contact with the bottom panel,
and clips (35) perpendicularly engaged in the bottom plate (22) and the top surface of the load-bearing bulkhead (26, 126, 226) for attaching the load-bearing bulkhead to the cover panel,
characterized in that the groove (30) has a section comprising, successively in a thickness direction of the upper plate, a wider bottom part (32) and a narrower mouth part (31),
and that the upper surface of the load-bearing wall (26, 126, 226) is wider than the bottom part (32) of the groove, the clips (35) being engaged in an area of the lower plate (22) offset laterally relative to the bottom portion (32) of the groove. Crate according to Claim 1, in which the groove (30) is made only in the upper plate (21) of the lid panel. Crate according to Claim 1 or 2, in which the fasteners (35) fasten the load-bearing partition (26, 126, 226) to the lid panel independently of the top plate (21). Body according to one of Claims 1 to 3, in which the groove (30) has a T-shaped section, in which the bottom part (32) of the groove corresponds to the horizontal bar of the T and the mouth (31) corresponds to the vertical bar of the T. Case according to one of Claims 1 to 4, in which the bottom part (32) of the groove has a width of between 20 and 30 mm. Body according to one of Claims 1 to 5, in which a difference between the width of the bottom part (32) of the groove and the width (W) of the upper surface of the load-bearing partition is greater than 10 mm. Body according to one of Claims 1 to 6, in which a center line of the bottom part (32) of the groove is located perpendicular to a center plane of the load-bearing partition (26, 126, 226). Body according to one of Claims 1 to 7, in which the attachments (35) are arranged on either side of a median plane of the load-bearing partition. Body according to one of Claims 1 to 8, in which the load-bearing partition (26, 126, 226) is made of wood, plywood or composite. Body according to one of Claims 1 to 9, in which the supporting partition (26, 126) has a uniform width wider than the bottom part of the groove. Body according to one of Claims 1 to 9, in which the internal partition (226) has an upper flange (52) arranged parallel against the lower plate (22) and a central portion (51) arranged under the upper flange, the flange upper part (52) being wider than the bottom part (32) of the groove, the central portion (51) having a width equal to or narrower than the bottom part (32) of the groove. Body according to one of Claims 1 to 10, in which the load-bearing partition (126) has a multilayer structure in a width direction, the multilayer structure comprising a core (41) of insulating material and two more rigid side plates (42). than the insulating material, the fasteners (35) being engaged in the side plates (42). Box according to one of Claims 1 to 12, comprising two parallel grooves (30) made in the lid panel and a respective internal partition (26, 126, 226) extending directly above each groove. Sealed and thermally insulating tank for storing a fluid, said tank comprising a tank wall (1) fixed to a bearing wall (2),
wherein the vessel wall comprises, in the thickness direction from the outside to the inside of said vessel, a secondary insulating barrier (3) retained on said supporting wall (2), a secondary waterproof membrane (4) retained on the said secondary insulating barrier, a primary insulating barrier retained on the said secondary waterproof membrane and a primary waterproof membrane (6) retained on the said primary insulating barrier, characterized in that the said primary insulating barrier consists essentially of boxes (5) according one of claims 1 to 13 juxtaposed and filled with a thermal insulation, the primary waterproof membrane (6) being retained on the cover panels of said boxes by welding supports (8) inserted in said grooves (30). Vessel (70) for the transport of a fluid, the vessel comprising a double hull (72) and a tank (71) according to claim 14 arranged in the double hull (72). Transfer system for a fluid, the system comprising a vessel (70) according to claim 15, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) of the vessel to a floating storage installation or land (77) and a pump for driving a fluid through the insulated pipes from or to the floating or land storage facility to or from the ship's tank. Method of loading or unloading a ship (70) according to claim 15, in which a fluid is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or terrestrial storage installation (77) to or from the tank (71) of the ship.