Tank wall with through-duct

Abstract

To enhance the fatigue strength of a tank wall in a region where a through-duct runs through a multilayer structure.SOLUTION: A thermally insulating sealed tank comprises a tank wall, a secondary thermally insulating barrier 9, a secondary sealed membrane 8, a primary thermally insulating barrier 7, and a primary sealed membrane 6. The tank also comprises a through-duct 5 running through the tank wall. The tank wall comprises, surrounding the through-duct 5, secondary thermally insulating blocks forming the secondary thermally insulating barrier 9, a first sealing layer forming the secondary sealing membrane 8, primary thermally insulating blocks forming the primary thermally insulating barrier 6, and a closure plate tightly connected to the primary sealing membrane 6.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the manufacture of sealed insulated tanks, in particular tanks designed to contain hot or cold liquids, more particularly tanks for storing and / or transporting liquefied gases at sea in load-bearing structures. [Background technology]

[0002] Technical background Sealed insulated tanks can be used in different industries to store hot or cold products. For example, in the energy sector, such a product may be liquefied natural gas (LNG), which is a liquid that can be stored at atmospheric pressure at about -163°C in storage tanks on land or in tanks located on floating structures. Such floating structures include in particular barges, liquefied natural gas carriers for transporting the product and offshore installations, known by the acronyms FPSO and FSRU, for storing, liquefying or regasifying the product.

[0003] Such sealed insulated tanks are made of one or more sealing membranes in combination with an insulating layer. Known in particular from French patent FR 2 781 557 is a sealed insulated tank with a tank wall fixed to a load-bearing structure, said tank wall having a multi-layer structure with a primary sealing membrane intended to be in contact with the product contained in the tank, a primary insulating barrier, a secondary sealing membrane and a secondary insulating barrier in succession.

[0004] The sealing membrane is sufficiently elastic to withstand stresses arising from, for example, hydrostatic pressure, dynamic pressure during cargo movement and / or temperature changes. However, such sealing membranes and the underlying insulation are relatively fragile and cannot always withstand the weight of a pylon, for example an LNG tank loading / unloading pylon. For this purpose, support legs may be provided, as in FR 2 961 580.

[0005] Furthermore, due to the thermodynamic situation in sealed insulated tanks during the storage of such liquids, a certain amount of vapor evaporation occurs, which results in fluctuations in the internal pressure of the tank. To control the pressure in such tanks, for example, the evaporated gases are collected and conveyed to an evaporation manifold, whereby they are reliquefied or combusted in the ship's propulsion engine. For this purpose, a manifold conduit may be provided, as in patent FR 2 984 454.

[0006] Thus, there are many different functions that may require the penetration of the multi-layer structure of the tank wall by a penetration conduit. Summary of the Invention [Problem to be solved by the invention]

[0007] overview In the tanks mentioned above, when the tank is filled with a very cold liquid, for example LNG, deformations of all the elements occur due to the temperature changes that affect the tank walls when the tank is emptied and, conversely, when it returns to ambient temperature. In addition to these effects of thermal contraction and expansion, which are repeated over the service life of a sealed, insulated tank, tanks in ships are also subjected to stresses due to the deformations of the ship's hull at sea, which result in fatigue of the elements. This must be monitored over time to prevent failures.

[0008] One idea behind the present invention is to increase the fatigue strength of the tank wall in the area where the through-conduit penetrates the multi-layer structure. [Means for solving the problem]

[0009] According to one embodiment, the present invention provides a sealed insulated tank disposed within a load-bearing structure to contain a fluid, comprising: a tank wall fixed to a load-bearing structure, the tank wall having a multi-layer structure including, successively in a thickness direction from the outside to the inside of the sealed insulated tank, a secondary insulating barrier, a secondary sealing membrane supported by the secondary insulating barrier, a primary insulating barrier supported by the secondary sealing membrane, and a primary sealing membrane supported by the primary insulating barrier and intended to come into contact with a fluid contained in the sealed insulated tank, the multi-layer structure including a primary space disposed between the primary sealing membrane and the secondary sealing membrane, the primary space housing the primary insulating barrier; a through-pipe disposed through the tank wall, the primary sealing membrane being tightly connected to the through-pipe, and the tank wall being configured to surround the through-pipe; secondary insulation blocks secured to the load-bearing structure, the secondary insulation blocks forming a secondary insulation barrier surrounding the through-pipe, each of the secondary insulation blocks having at least one lateral surface extending in a thickness direction of the tank wall, the secondary insulation blocks being arranged relative to one another to define a space between the opposing lateral surfaces of two adjacent secondary insulation blocks; a sealing layer covering the secondary insulation block and forming a secondary sealing membrane; a sealing plate arranged parallel to the tank wall, the sealing plate having an inner surface facing the inside of the sealed insulated tank, the inner surface being at the same level as the sealing layer, the sealing plate being arranged to surround the through-pipe, and the secondary sealing membrane being extended up to the sealing plate; an outer conduit extending from the sealing plate to the outside of the sealed insulated tank in parallel to the through conduit so as to surround the through conduit, the outer conduit communicating with the primary space so that inert gas can flow between the primary space and the outer conduit; primary insulation blocks disposed on the secondary sealing membrane, the primary insulation blocks forming a primary insulation barrier surrounding the through-pipe, a first and a second of the primary insulation blocks having lateral faces extending in the thickness direction of the tank wall, the lateral faces having a cut-out portion intended to receive a portion of the through-pipe and at least one interface portion adjacent the cut-out portion, the interface portion of the first primary insulation block being disposed opposite the interface portion of the second primary insulation block; Equipped with The secondary insulation block and the first and second primary insulation blocks are arranged relative to each other such that an interface portion of the first primary insulation block and an interface portion of the second primary insulation block do not overlap a space between two adjacent secondary insulation blocks in a thickness direction. To provide a sealed insulated tank.

[0010] These features help to increase the fatigue resistance of the secondary sealing membrane while maintaining a flexible sealing membrane layer disposed across the secondary insulation block. Indeed, the absence of overlap in thickness between the interface portions of two adjacent primary insulation blocks and the space between adjacent secondary insulation blocks eliminates the risk of increased stress in the secondary sealing membrane due to thermal contraction or compressive forces.

[0011] According to embodiments, such a sealed insulated tank may have one or more of the following features:

[0012] According to one embodiment, the sealing layer is a first sealing layer covering a secondary insulation block, and the tank wall comprises a second sealing layer tightly fixed across the first sealing layer and the inner surface of the sealing plate to surround the through conduit, the second sealing layer extending the secondary sealing membrane to the sealing plate.

[0013] According to one embodiment, the second sealing layer comprises at least two sealing strips, each sealing strip being disposed across two adjacent secondary insulating blocks.

[0014] According to one embodiment, the second sealing layer has two sealing strips aligned with each other on either side of the through conduit so as to cover the space.

[0015] According to one embodiment, the two sealing strips of the second sealing layer are positioned perpendicular to the at least one interface portion of the first primary insulation block and the at least one interface portion of the second primary insulation block.

[0016] According to one embodiment, the tank wall comprises two prefabricated panels arranged on either side of the through-conduit, each of these prefabricated panels comprising a lower insulating block forming a secondary insulating block, a first sealing layer covering the secondary insulating block and an upper insulating block arranged in the central area between the first sealing layer and the lower insulating block without covering the peripheral area of ​​the first sealing layer, said upper insulating block being part of the primary insulating barrier, said primary insulating block being arranged on said peripheral area of ​​the first sealing layer of the two prefabricated panels and on said space between the upper insulating blocks of the two prefabricated panels.

[0017] According to one embodiment, the primary sealing membrane has a sealing plate which is tightly connected to each other at its edges, the upper insulation block of the two prefabricated panels has fastening strips to said edges of the sealing plate in order to fasten the sealing plate to said prefabricated panels, and the primary insulation block has heat protection strips to said edges of the sealing plate such that the sealing plate is not fastened to said primary insulation block.

[0018] According to one embodiment, the primary sealing membrane comprises at least one series of corrugations with corrugations extending along parallel directrixes, said corrugations protruding towards the inside of the sealed insulated tank, at least one directrix of a given corrugation of the series of corrugations is interrupted by a window, the corrugations preferably have an open end at the window, and the sealed insulated tank has at least one end piece for closing the open end of at least one said corrugation.

[0019] According to one embodiment, the window interrupts at least two directrixes of the corrugations of said at least one series of corrugations, and the through conduit is centred at a position between two of said directrixes of the interrupted corrugations.

[0020] The arrangements and features described above with respect to a series of parallel corrugations may, if desired, be applied to several series of parallel corrugations each extending in a different direction.

[0021] According to one embodiment, the primary sealing membrane has a first series of corrugations and a second series of corrugations intersecting the first series of corrugations, the window interrupts at least two directrixes of corrugations of the first series of corrugations and at least two directrixes of corrugations of the second series of corrugations, and the through conduit is centered at a position between the two interrupted directrixes of corrugations of the first series of corrugations and the two interrupted directrixes of corrugations of the second series of corrugations.

[0022] According to one embodiment, the directrix of the corrugations of the first series of corrugations is perpendicular to the directrix of the corrugations of the second series of corrugations.

[0023] The aforementioned windows may have different shapes, depending in particular on the shape of the lead-through conduit and / or the shape of the components of the primary sealing membrane.

[0024] According to one embodiment, the window is a quadrilateral having two sides parallel to the directrix of the corrugations of the first series of corrugations and two sides parallel to the directrix of the corrugations of the second series of corrugations. In particular, the window may be a square, a rectangle or a parallelogram.

[0025] According to one embodiment, the through conduit has a circular cross section and passes through the center of the window.

[0026] According to one embodiment, the outer conduit comprises a first circumferential connecting plate and a second circumferential connecting plate, the second circumferential connecting plate being tightly fixed to the first circumferential connecting plate around the entire circumference of the first circumferential connecting plate, the first circumferential connecting plate extending from the second circumferential connecting plate towards the outside of the sealed insulated tank parallel to the through-pipe, and the second circumferential connecting plate being tightly fixed to the sealing plate and protruding parallel to the through-pipe towards the load-bearing structure.

[0027] According to one embodiment, the tank wall also has at least one closing plate, which is arranged in the primary insulation block so as to surround the through-pipe and is tightly connected to the through-pipe.

[0028] According to one embodiment, the closure plate consists of a one-piece metal plate surrounding the through-conduit.

[0029] According to one embodiment, at least one of the primary insulating blocks has at least one slot and the closing plate has at least one slot covered by an end piece overlapping said slot of the primary insulating block, thereby allowing the inert gas to flow between the corrugations and the outer conduit.

[0030] According to one embodiment, the tank wall comprises a thermal barrier sheet interposed between the primary insulation block and the closing plate.

[0031] Advantageously, the heat insulating sheet is integrally wrapped around the through-pipe.

[0032] Advantageously, the thermal barrier sheet comprises at least one slot which overlaps one slot of the primary insulation block and is positioned below one slot of the closure plate.

[0033] According to one embodiment, the through conduit forms a passage between the inside of the sealed insulated tank and a steam manifold located outside said sealed insulated tank.

[0034] Such tanks may, inter alia, be part of onshore storage facilities for storing, for example, liquefied gas or may be installed in coastal or deep-sea floating structures, in particular liquefied natural gas carriers, LPG carriers, Floating Storage and Regasification Units (FSRUs), Floating Production Storage and Offloading (FPSO) installations.

[0035] According to one embodiment, the present invention also provides a vessel used for transporting cryogenic liquid products, the vessel having a double hull and a sealed insulated tank disposed within the double hull.

[0036] According to one embodiment, the invention also provides the use of a vessel for loading or unloading a cryogenic liquid product, the cryogenic liquid product being transferred through an insulating pipe from an onshore or floating storage facility to a sealed insulated tank provided on the vessel, or from a sealed insulated tank provided on the vessel to an onshore or floating storage facility through an insulating pipe.

[0037] According to one embodiment, the present invention also provides a transfer system for cryogenic liquids, comprising a vessel, an insulated pipe arranged to connect a sealed insulated tank installed within the hull of the vessel to an onshore or floating storage facility, and a pump for pumping a cryogenic liquid product stream from the onshore or floating storage facility through the insulated pipe to the sealed insulated tank installed on the vessel or from the sealed insulated tank installed on the vessel through the insulated pipe to the onshore or floating storage facility.

[0038] The present invention can be better understood and further objects, details, features and advantages thereof will be more particularly explained in the following detailed description of some particular embodiments of the invention, given by way of non-limiting examples only, with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0039] [Figure 1] FIG. 2 is a cross-sectional view of a tank wall with a fluid collection device according to one embodiment of the present invention. [Diagram 2] 2 is an enlarged cross-sectional view of region II shown in FIG. [Diagram 3] FIG. 3 is a partially exploded perspective view of the tank wall area shown in FIG. 2. [Figure 4] FIG. 3 is a plan view along the axis of the through-conduit of the region of the tank wall shown in FIG. 2, showing the secondary insulating barrier surrounding the through-conduit without the primary insulating barrier. [Diagram 5] FIG. 5 is a view similar to FIG. 4 showing the primary insulating barrier. [Figure 6] FIG. 2 is an exploded perspective view of a primary insulation block that may be used in the primary insulation barrier. [Figure 7] FIG. 6 is a view similar to FIG. 5 showing the positioning of the thermal barrier sheet and strips to the primary insulation barrier. [Figure 8] 8 is a view similar to FIG. 7 at an intermediate stage in the assembly of the primary sealing membrane; [Figure 9] 9 is a view similar to FIG. 8 at a further stage in the assembly of the primary sealing membrane. [Figure 10] FIG. 10 is a view similar to FIG. 9 showing the primary sealing membrane. [Figure 11] 11 is a perspective view of an end piece that may be used in the manufacture of the primary sealing membrane shown in FIG. 10. [Figure 12] FIG. 2 is a cutaway schematic view of a tank in a liquefied natural gas carrier and a loading / unloading terminal for the tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0040] Description of the embodiments With reference to Figure 1, a sealed insulated tank 1 has a tank wall 2. The tank wall 2 is fixed to the inner surface of a corresponding wall of a load-bearing structure 3. The load-bearing structure 3 is for example the inner hull of a double-hull ship or land structure. Figure 1 is a partial view of the sealed insulated tank 1 showing only the roof wall.

[0041] As is conventional, the terms "above", "above", "upper" and "superior" generally refer to positions toward the inside of the sealed insulated tank 1, and "below", "below", "lower" and "lower" generally refer to positions toward the outside of the sealed insulated tank 1, regardless of the orientation of the tank wall 2 relative to the Earth's gravitational field.

[0042] The sealed insulated tank 1 may have different shapes, for example a prismatic shape in the hull of a ship or a cylindrical shape on land or another shape.

[0043] The following embodiments describe a sealed insulated tank 1 intended for the storage and / or transportation of liquefied natural gas at sea. In a variant not described, such a sealed insulated tank 1 may be a tank used for storing other products at low or high temperature on land.

[0044] In figures 1 and 2 a fluid collection device 4 is shown. Such a device comprises a through-conduit 5 passing through the tank wall 2, for example the roof wall of a sealed insulated tank 1.

[0045] 1, the tank wall 2 comprises, successively in the thickness direction from the inside of the sealed insulated tank 1 towards the load-bearing structure 3, a primary sealing membrane 6 in contact with the liquefied gas, a primary insulating barrier 7, a secondary sealing membrane 8 and a secondary insulating barrier 9. The primary insulating barrier 7, the secondary sealing membrane 8 and the secondary insulating barrier 9 are essentially a set of prefabricated panels in contact with the mastic bead 11 and fixed to the load-bearing structure 3.

[0046] The fluid collection device 4 comprises a barrel 12 extending outside the load-bearing structure 3 and a through-conduit 5 fixed inside the barrel 12. The barrel 12 and the through-conduit 5 are cylindrical bodies of circular cross section. However, other shapes are possible. The load-bearing structure 3 has a circular opening 13. The barrel 12 is welded to surround the circular opening 13. The through-conduit 5 penetrates the tank wall 2 in the center of the circular opening 13. The through-conduit 5 thus penetrates the primary sealing membrane 6, the secondary sealing membrane 8, the primary insulating barrier 7 and the secondary insulating barrier 9 into the sealed insulated tank 1. In particular, the through-conduit 5 is connected to a steam manifold outside the sealed insulated tank. The steam manifold takes off steam and conveys it to the ship's propulsion system to supply the ship or to the liquefaction system, which then returns the liquefied gas to the tank.

[0047] The primary sealing membrane 6 is tightly connected to the through conduit 5. The secondary sealing membrane 8 is also tightly connected to the through conduit 5, except for a passage that allows a gas phase to flow between the primary sealing membrane 6 and the secondary sealing membrane 8 towards the two secondary conduits 14, 15. The gas phase is typically dinitrogen or another inert gas. The space between the primary sealing membrane 6 and the secondary sealing membrane 8 thus forms a primary sealing space that is connected to the two secondary conduits 14, 15.

[0048] Furthermore, the barrel 12 is tightly connected to the load-bearing structure 3. An insulating layer 16 is evenly distributed over the outside of the through-conduit 5, which has a smaller diameter than the circular opening 13. The gap between this insulating layer 16 and the circular opening 13 thus allows the gas phase to flow between the secondary insulating barrier 9 and the intermediate space between the barrel 12 and the insulating layer 16. The gas phase is typically dinitrogen or another inert gas. The intermediate space and the space between the load-bearing structure 3 and the secondary insulating barrier 9 thus form a secondary sealed space.

[0049] Two secondary conduits 14, 15 run parallel to the through conduit 5 within the insulating layer 16 from the outside of the barrel 12 to the primary sealed space. The first secondary conduit 14 provides a passage between the primary sealed space and a discharge member (not shown) which controls the gas phase in this space. The second secondary conduit 15 provides a passage between the primary space and a pressure measuring device (not shown). In particular, these two secondary conduits 14, 15 make it possible to flush the primary sealed space with an inert gas, for example nitrogen.

[0050] Two further conduits (not shown) are welded to the barrel 12 and open into a secondary sealed space inside the barrel 12, which allows for the control of the gas phase and also the measurement of the pressure in this secondary sealed space. A conduit connected to the secondary sealed space also allows for the flushing of the secondary sealed space with an inert gas, for example nitrogen.

[0051] In the following, the region II of the tank wall 2 through which the through-pipe 5 penetrates will be described in detail with reference to FIGS.

[0052] Near the through-pipe 5, two prefabricated panels 10a, 10b are arranged. Referring to Fig. 4, these prefabricated panels 10a, 10b comprise a secondary insulation block 17 secured to the load-bearing structure 3. This secondary insulation block 17 comprises a rigid lower panel 18 supported by mastic beads 11 and an insulation layer 19 made of polyurethane foam.

[0053] Attached to the entire surface of the insulating layer 19 of the secondary insulating block 17 is a first sealing layer 20 of a composite material, for example including a metal sheet and a fiberglass layer impregnated in resin. This first sealing layer 20 is a component of the secondary sealing membrane 8.

[0054] The prefabricated panels 10a, 10b also include an upper insulation block 21a, 21b having an insulation layer 22 made from polyurethane foam partially covering and partially adhering to the first sealing layer 20. A rigid upper panel 23 covers the insulation layer 22 and together with it forms an element of the primary insulation barrier 7.

[0055] As described above with reference to figure 1, the through-conduit 5 penetrates the circular opening 13, the secondary insulating barrier 9, the secondary sealing membrane 8, the primary insulating barrier 7 and the primary sealing membrane 6. A circular closure plate 24 extends beyond the load-bearing structure 3 and surrounds the through-conduit 5. This closure plate 24 has an upper surface parallel to the tank wall 2. To this upper surface the insulating layer 16 surrounding the through-conduit 5 is bonded. The closure plate 24 also has two orifices 25, 26 to which the two secondary conduits 14, 15 are welded.

[0056] The sealing between the secondary insulating barrier 9 and the through-conduit 5 is achieved by means of a closing plate 24, a first circumferential connecting plate 27, a second circumferential connecting plate 28 and a sealing plate 29. The tubular first circumferential connecting plate 27 is tightly fastened to the closing plate 24 over its entire circumference and runs parallel to the through-conduit 5 in the sealed insulated tank 1, thereby forming an outer conduit. At its end opposite the closing plate 24, said circumferential connecting plate is connected to a circular sealing plate 29 via a second circumferential connecting plate 28, also tubular. The closing plate 24, the sealing plate 29 and the circumferential connecting plates 27, 28 thus form an inner space 30 in the outer conduit adjacent to the outer wall of the through-conduit 5. A second sealing layer 31 is tightly fastened across the first sealing layer 20 and the sealing plate 29 to seal the secondary sealing membrane 8.

[0057] The sealing plate 29 has a circular passage 32 traversed by the through conduit 5. The diameter of this circular passage 32 is larger than the diameter of the through conduit 5 so as to leave a gap between the sealing plate 29 and the through conduit 5. This gap allows the gas phase to flow from the primary sealing space between the primary sealing membrane 6 and the secondary sealing membrane 8 towards the inner space 30.

[0058] To vent the steam from the inner space 30, the two secondary conduits 14, 15 are tightly connected to the closing plate 24. This construction allows flushing with an inert gas. To provide insulation, the inner space 30 is filled with a steam-permeable and gas-permeable insulator.

[0059] The second circumferential connecting plate 28 is tubular and welded to the lower surface of the sealing plate 29. The inner diameter of the second circumferential connecting plate 28 is substantially equal to the outer diameter of the first circumferential connecting plate 27. Therefore, the circumferential connecting plates 27, 28 can be fitted together and slidably cooperate at the non-welded portion. Therefore, when the second circumferential connecting plate 28 is welded to the first circumferential connecting plate 27, the gap between the sealing plate 29 and the load-bearing structure 3 can be adjusted to accurately align the sealing plate 29 with the secondary sealing membrane 8. Furthermore, by fitting the first circumferential connecting plate 27 and the second circumferential connecting plate 28 together, it is possible to center the through-pipe 5 in the opening 13 and to set the direction of the sealing plate 29. The welds between the closure plate 24 and the first circumferential connecting plate 27, the welds between this first circumferential connecting plate 27 and the second circumferential connecting plate 28, and the welds between this second circumferential connecting plate 28 and the sealing plate 29 are made to form a seal between these elements.

[0060] The closing plate 24, the sealing plate 29, the first circumferential connecting plate 27 and the second circumferential connecting plate 28 are metallic elements and are made, for example, from stainless steel.

[0061] 1, in order to reduce the stresses on the joints made around the through-conduit 5, the through-conduit is secured at a portion 33 of the through-conduit spaced away from the load-bearing structure 3 in a direction away from the inside of the sealed insulated tank 1. This reduces the stresses on the joints in the tank wall 2. The securing means comprises a frusto-conical metal element 34 extending into the barrel 12.

[0062] Referring to Figures 1 and 2, fins 40 are regularly arranged in the inner space 30 between the through conduit 5 and the first circumferential connecting plate 27 to position and fix the first circumferential connecting plate 27 relative to the through conduit 5.

[0063] 2-5, to form a primary insulation barrier 7 between the through conduit 5 and the prefabricated panels 10a, 10b, two primary insulation blocks 35 are positioned across the secondary insulation blocks 17 and the sealing plate 29 of the prefabricated panels 10a, 10b. Like the upper insulation blocks 21a, 21b, the primary insulation blocks 35 have an insulating layer 36 supported by the secondary insulation barrier 9. An upper panel 37 is positioned above the insulating layer 36.

[0064] The upper insulation blocks 21a, 21b of the prefabricated panels 10a, 10b and the primary insulation block 35 support a primary sealing membrane 6 made of metal plate with corrugations 38a, 38b which form elastic areas designed to absorb thermal contraction, static and dynamic compression forces. Such corrugated or checkered sheet metal sealing barriers are described in particular in patents FR 1 379 651, FR 1 376 525, FR 2 781 557 and FR 2 861 060.

[0065] The primary sealing membrane 6 is tightly connected to the through-conduit 5 by a flange 39 having an L-shaped cross section. The flange 39 is welded to the primary sealing membrane 6 and to the through-conduit 5.

[0066] In FIG. 3 the structure of the elements forming the tank wall 2 so as to surround the through-conduit 5 is shown in more detail.

[0067] The through-pipe 5 and the first circumferential connecting plate 27 penetrate the load-bearing structure 3 in the center of the opening 13. The first circumferential connecting plate 27 is centered in the opening.

[0068] A glass wool filling is inserted in the inner space 30. As mentioned above, this filling is porous, which allows the gas phase to flow freely in the inner space 30 between the primary sealed space and the secondary conduits 14, 15 (not shown in FIG. 3).

[0069] The sealing plate 29 is positioned so as to be precisely aligned with the secondary sealing membrane 8 by welding the second circumferential connecting plate 28 to the first circumferential connecting plate 27. To avoid the risk of burning the glass wool filling, a heat shield (not shown) is placed between the filling and the circumferential connecting plates 27, 28.

[0070] 3 to 5, the secondary insulation barrier 9, the secondary sealing membrane 8 and the primary insulation barrier 7 are made from two prefabricated panels 10a, 10b. Each of the prefabricated panels 10a, 10b surrounding the through-pipe 5 is formed in a stepped shape with a secondary insulation block 17 constituting an element of the secondary insulation barrier 9, a first sealing layer 20 completely covering the upper surface of the secondary insulation block 17, and a smaller upper insulation block 21a, 21b constituting an element of the primary insulation barrier 7. The upper insulation block 21a, 21b of the prefabricated panels 10a, 10b has a U-shaped section when viewed from above and is positioned relative to the secondary insulation block 17 so that the peripheral area of ​​the first sealing layer 20 remains exposed.

[0071] In particular, each secondary insulation block 17 has a face 41 with a semicircular cutout for receiving the first circumferential connecting plate 27 and the second circumferential connecting plate 28. The semicircle has a diameter larger than the diameter of the first circumferential connecting plate 27 and the second circumferential connecting plate 28, as shown in FIG. 2, thereby leaving a space for a glass wool filling 73 to be inserted between the first and second circumferential connecting plates 27, 28 and the secondary insulation block 17.

[0072] The two secondary insulating blocks 17 are designed to form a space between them in the form of two radial interpanel spaces 42a, 42b. To ensure the continuity of the secondary insulating barrier 9, each of the two radial interpanel spaces 42a, 42b is filled with a glass wool filling (not shown), which allows the gas phase to flow through the secondary insulating barrier 9 and in particular the tank wall to be inertized with an inert gas, for example nitrogen.

[0073] The prefabricated panels 10a, 10b may be prefabricated by combining polyurethane foam and plywood for the primary and secondary insulation barriers 7, 9. Thus, the secondary insulation block 17 comprises a lower panel 18 and an insulating foam layer 19, and the upper insulation block 21a, 21b comprises an insulating layer 22 and an upper panel 23. The upper panel 23 of the upper insulation block 21a, 21b has lateral and longitudinal countersunk surfaces designed to receive fastening strips 43 to which the primary sealing membrane 6 is welded, as described below.

[0074] The two prefabricated panels 10a, 10b are juxtaposed to surround the through-pipe 5. Each prefabricated panel 10a, 10b also has a space 44 which allows access to pins 71 pre-welded to the load-bearing structure for fastening the prefabricated panels 10a, 10b during assembly.

[0075] The second sealing layer 31 is bonded to the sealing plate 29 over the first sealing layer 20. The second sealing layer 31 also includes two radial sealing strips 31a, 31b disposed across the two secondary insulation blocks 17 above the spaces 42a, 42b.

[0076] Two primary insulation blocks 35 and two intermediate blocks 45 are positioned above the second sealing layer 31 and the first sealing layer 20 to complete the primary insulation barrier 7. The intermediate blocks 45 are assembled to the radial sealing strips 31a, 31b of the second sealing layer 31.

[0077] 6, each of the primary insulation blocks 35 has a lateral face 46 with a semicircular cutout 76 for receiving the through conduit 5 and a straight interface portion 47 adjacent the cutout 76. When the primary insulation blocks 35 are assembled, the cutouts 76 define a diameter greater than the diameter of the through conduit 5, as shown in FIG.

[0078] 5, the two primary insulation blocks 35 are designed to meet without contact at the two interface portions 47. The two primary insulation blocks 35 are positioned above the second sealing layer 31, so that the interface portions 47 do not overlap the radial inter-panel spaces 42a, 42b in the thickness direction. In FIG. 3, the direction D1 of the interface portions 47 of the primary insulation blocks 35 is perpendicular to the direction D2 of the radial inter-panel spaces 42a, 42b.

[0079] 9 and 10, the primary sealing membrane 6 is formed by a number of corrugated sealing plates 48. The inner surface of these sealing plates 48 is intended to be in contact with the fluid contained in the sealed insulated tank 1. The sealing plates 48 are thin-walled metal elements, for example stainless steel sheets. The corrugated sealing plates 48 are cut to form square windows 49 surrounding the through-conduit 5 and allowing the through-conduit 5 to pass through. In this case, the windows 49 are square, which makes it easy to cut the sealing plates 48 to the desired shape. However, the windows 49 may be of different shapes, depending in particular on the shape of the through-conduit 5.

[0080] The sealing plate 48 of the primary sealing membrane 6 has a number of corrugations 38a, 38b protruding towards the inside of the sealed insulated tank 1. More specifically, the primary sealing membrane 6 has a first series of corrugations 38a, called transverse corrugations, and a second series of corrugations 38b, called longitudinal corrugations, arranged perpendicular to one another. The first series of corrugations 38a is higher than the second series of corrugations 38b.

[0081] In figure 9 the edges of the sealing plates 48 are shown by means of a continuous line. The sealing plates 48 are welded to one another with a minimal overlap area 77 in order to seal the primary sealing membrane 6. The welding is a lap welding, the method being described in detail, for example, in patent FR 1 387 955. The sealing plates 48 can be produced in various shapes and sizes and thus the welded areas can be positioned in different positions.

[0082] Unlike the upper insulation blocks 21a, 21b of the prefabricated panels 10a, 10b, the primary insulation block 35 does not have anchor strips 43. In fact, for fabricating the primary sealing membrane 6 around the through-pipe 5, the closure plate 51, shown in Figs. 3 and 8-10, arranged on the thermal insulation sheet 72, defines a square of slightly larger size than the window 49 provided in the sealing plate 48. In the center of the closure plate 51, an opening is cut to allow the passage of the through-pipe 5. The closure plate 51 is tightly welded to the through-pipe 5 via a flange 39.

[0083] 7-9, the sealing plate 48 of the primary sealing membrane 6 is welded to the anchor strip 43 of the upper insulation block 21a, 21b and to the intermediate block 45. Welding the sealing plate 48 to the anchor strip 43 makes it possible to hold the primary sealing membrane 6 to the primary insulation barrier 7. In particular, to prevent damage to the primary insulation block 35 when the sealing plate 48 is welded, a thermal barrier strip 50 is arranged on the primary insulation block 35 against the edge of the sealing plate 48. The thermal barrier sheet 72 and the thermal barrier strip 50 are made of a heat-resistant material, for example a composite glass fiber material. In the center of the thermal barrier sheet 72, an opening is cut so that the through-conduit 5 can pass through.

[0084] The primary sealing membrane 6 surrounding the through conduit 5 is completed by first welding the edges of the sealing plate 48 that define the windows 49 to a closure plate 51 and then closing the ends of the interrupted corrugations 38a, 38b with end pieces 52. Indeed, since the diameter of the through conduit 5 is greater than the gaps between the corrugations of the first series of corrugations 38a, the parts of the transverse corrugations that have directrixes that intersect with the through conduit are interrupted by the windows 49. Similarly, since the diameter of the through conduit 5 is greater than the gaps between the corrugations of the second series of corrugations 38b, the parts of the longitudinal corrugations that have directrixes that intersect with the through conduit 5 are interrupted by the windows 49 that surround the through conduit 5.

[0085] 11, the end piece 52 comprises a two-part base plate 53, 54 designed to be tightly welded to the closure plate 51 and the sealing plate 48, respectively, and a shell 55 designed to be tightly welded to the ends of the corrugations. The recess 56 between the base plate parts 53, 54 has a width substantially equal to the thickness of the sealing plate 48.

[0086] 3, 5 and 6, the upper panel 37 of the primary insulation block 35 has four slots 57 extending through it, the closing plate 51 has slots 69 overlapping the slots 57 of the primary insulation block 35, and the thermal barrier sheet 72 has slots 70 overlapping the slots 57 of the primary insulation block 35 and positioned below the slots 69 of the closing plate 51. During installation of the primary sealing membrane 6, the end pieces 52 overlap the slots 57, 69, 70, which allows the gas phase in the corrugations 38a, 38b to flow towards the insulating layer 36 of the primary insulation block 35. The insulating layer 36 also has a connecting slot 74 positioned below the slots 57 of the upper panel 37. From this connecting slot 74, three parallel slots 75 each extend towards a semicircular notch 76 in the primary insulation block 35. Thus, the gas phase passing through the upper panel 37 can flow outside the primary insulation block 35 and into the space between the primary insulation block 35 and the through conduit 5 .

[0087] The particular structure of the primary insulating block 35, connected with the gap between the circular passage 32 and the through-conduit 5 and with the inner space 30 with the porous filling, forms circuits facilitating the flow of the gas phase in the primary sealed space, in particular from the corrugations 38a, 38b to the secondary conduits 14, 15 and vice versa. Similarly, as mentioned above, the space between the opening 13 and the first circumferential connecting plate 27 and the space between the load-bearing structure 3 and the secondary insulating block 17 form circuits facilitating the flow of the gas phase between the secondary sealed space and the barrel 12. These circuits make it possible, in particular, to inertize the tank wall 2 with an inert gas, for example dinitrogen.

[0088] 9 and 10 show that the size of the window 49 is actually larger than the diameter of the through conduit 5. Thus, the window 49 formed in the primary sealing membrane 6 may tend to interrupt the corrugation having a directrix very close to the through conduit 5 without actually intersecting the through conduit 5.

[0089] As shown in Figures 9 and 10, the centre of the through conduit 5 is positioned between the directrixes of the interrupted transverse corrugations 38a and between the directrixes of the interrupted longitudinal corrugations 38b, more precisely in the middle of these directrixes. As a result of this positioning, the directrix intersects the through conduit 5 along a chord that is in any case shorter than the diameter of the through conduit 5. As a result, taking into account the space between the edge of the window 49 and the through conduit 5, such a positioning of the through conduit 5 makes it possible to interrupt the transverse corrugations 38a or the longitudinal corrugations 38b over a shorter distance than if the directrix intersected the through conduit 5 along its maximum transverse or longitudinal dimension, i.e. its diameter, since in this case the through conduit 5 is a cylinder of circular cross section. It is beneficial to interrupt the corrugations 38a, 38b of the primary sealing membrane 6 over the shortest possible distance, since interruptions tend to locally reduce the flexibility of the primary sealing membrane 6, thereby increasing the likelihood of localized fatigue and wear.

[0090] Centering the through conduit 5 midway between the interrupted transverse corrugations 38a and the interrupted longitudinal corrugations 38b provides optimal results. However, other shapes and respectively different centerings for the through conduit 5 may be considered. In any case, one principle that can be utilized to adapt the positioning of the through conduit 5 between the corrugations 38a, 38b is to select a position that minimizes or at least reduces the dimension of the through conduit 5 that is crossed by the directrix of the interrupted corrugations 38a, 38b. If the specific shape of the primary sealing membrane 6 means that multiple corrugations 38a, 38b are interrupted over different lengths, the important parameter for optimizing the positioning of the through conduit 5 may be the longest interruption length obtained or the cumulative interruption length.

[0091] The through conduit 5 requires a window 49 that is approximately twice the size of the gap between the two corrugations 38a, 38b, which in this case are equidistant. To achieve this, two corrugations 38a, 38b of each series of corrugations are interrupted. However, this arrangement of the through conduit 5 and the nearby tank wall 2 may be adapted to other dimensions of the through conduit 5. For example, in the case of a larger through conduit, the corresponding window 49 may interrupt a larger number of corrugations 38a, 38b of one or each series of corrugations, for example three, four or more corrugations.

[0092] In the embodiment described above, the through conduit 5 passes through the ceiling wall of the sealed insulated tank 1, but in other embodiments the through conduit may pass through the tank wall 2 above the side wall of the sealed insulated tank 1 or at any other position in the sealed insulated tank 1.

[0093] The above described sealed insulated tank 1 may be used in different types of installations, for example on land or in floating structures, for example liquefied natural gas carriers or other structures.

[0094] Referring to FIG. 12, a cutaway view of a liquefied natural gas carrier 58 shows a sealed insulated tank 1 having a generally prismatic shape mounted within a double hull 59 of the liquefied natural gas carrier 58.

[0095] The tank wall 2 includes a primary sealing membrane 6 intended to come into contact with the LNG contained in the sealed insulated tank 1, a secondary sealing membrane 8 arranged between the primary sealing membrane 6 and a double hull 59 of the liquefied natural gas carrier, and two insulating barriers 7, 9 arranged respectively between the primary sealing membrane 6 and the secondary sealing membrane 8 and between the secondary sealing membrane 8 and the double hull 59 of the liquefied natural gas carrier 58.

[0096] As is known, a loading / unloading pipe 60 located on the upper deck of the liquefied natural gas carrier 58 is connected to a marine or port terminal using appropriate connectors, thereby enabling the transport of loaded liquefied gas, e.g. LNG, to or from the sealed insulated tank 1.

[0097] Also shown in FIG. 12 is a marine terminal with loading / unloading points 61 , subsea lines 62 and onshore facilities 63 .

[0098] The loading / unloading point 61 is a static offshore installation with a movable arm 64 and a support 65 that holds the movable arm 64. The movable arm 64 supports a bundle of insulated hoses 66 that can be connected to the loading / unloading pipe 60. The directionally adjustable movable arm 64 can be adapted to any size of liquefied natural gas carrier 58. A connecting line (not shown) extends inside the support 65. The loading / unloading point 61 allows the liquefied natural gas carrier 58 to be unloaded from the onshore installation 63 or the onshore installation 63 to be loaded onto the liquefied natural gas carrier 58. Such an installation has a liquefied gas storage tank 67 and a connecting line 68 connected to the loading / unloading point 61 via a subsea line 62.

[0099] The subsea line 62 allows the liquefied gas to be transferred over large distances, e.g. 5 km, between the loading / unloading point 61 and the onshore facility 63. This allows the liquefied natural gas carrier 58 to be kept far from shore during loading and unloading operations.

[0100] To generate the pressure required to transport the liquefied gas, pumps installed on board the liquefied natural gas carrier 58 and / or pumps installed at the onshore facility 63 and / or pumps installed at the loading / unloading point 61 are used.

[0101] Although the present invention has been described with respect to some specific embodiments, it is of course not limited to these embodiments, but encompasses all technical equivalents of the described means and combinations thereof that fall within the scope of the present invention.

[0102] Use of the verbs "comprise" or "include", including their conjugations, does not exclude the presence of other elements or steps in addition to those stated in a claim.

[0103] In the claims, any reference signs placed between parentheses shall not be construed as limiting any particular claim.

Claims

1. A sealed insulated tank (1) arranged within a load-bearing structure (3) to contain a fluid, a tank wall (2) fixed to the load-bearing structure (3), the tank wall (2) having a multilayer structure comprising, successively in the thickness direction from the outside to the inside of the sealed insulated tank (1), a secondary insulating barrier (9), a secondary sealing membrane (8) supported by the secondary insulating barrier (9), a primary insulating barrier (7) supported by the secondary sealing membrane (8), and a primary sealing membrane (6) supported by the primary insulating barrier (7) and intended to be in contact with the fluid contained in the sealed insulated tank (1), the multilayer structure comprising a primary space located between the primary sealing membrane (6) and the secondary sealing membrane (8), the primary space containing the primary insulating barrier (7); a through-pipe (5) arranged through the tank wall (2), the primary sealing membrane (6) being tightly connected to the through-pipe (5), the tank wall (2) surrounding the through-pipe (5); - secondary insulation blocks (17) fixed to the load-bearing structure (3), said secondary insulation blocks (17) forming the secondary insulation barrier (9) surrounding the through-pipe (5), each of said secondary insulation blocks (17) having at least one lateral surface extending in the thickness direction of the tank wall (2), said secondary insulation blocks (17) being arranged relative to one another so as to form a space (42a, 42b) between the opposing lateral surfaces of two adjacent secondary insulation blocks (17); a sealing layer (20) covering said secondary insulating block (17) and forming said secondary sealing membrane (8); a sealing plate (29) arranged parallel to the tank wall (2), the sealing plate (29) having an inner surface facing the inside of the sealed insulated tank (1), the inner surface being at the same level as the sealing layer (20), the sealing plate being arranged to surround the through-conduit (5), the secondary sealing membrane (8) extending up to the sealing plate (29); - outer conduits (27, 28) extending parallel to and surrounding said through conduit (5), and communicating with said primary space so as to allow inert gas to flow between said primary space and said outer conduits (27, 28); - primary insulation blocks (35) arranged on the secondary sealing membrane (8), the primary insulation blocks forming the primary insulation barrier (7) surrounding the through-pipe (5), the first and second of the primary insulation blocks (35) each having a lateral surface extending in the thickness direction of the tank wall (2), the lateral surface (46) having a cutout (76) intended to accommodate a portion of the through-pipe (5) and at least one interface (47) adjacent to the cutout (76), the interface (47) of the first primary insulation block (35) being arranged opposite the interface (47) of the second primary insulation block (35); Equipped with The secondary insulation block (17) and the first and second primary insulation blocks (35) are arranged relative to each other such that the interface portion (47) of the first primary insulation block (35) and the interface portion (47) of the second primary insulation block (35) do not overlap the spaces (42a, 42b) between two adjacent secondary insulation blocks (17) in the thickness direction. A sealed insulated tank (1).

2. 2. The sealed insulated tank (1) according to claim 1, wherein the sealing layer (20) is a first sealing layer covering the secondary insulating block (17), and the tank wall comprises a second sealing layer (31) tightly fixed across the first sealing layer (20) and the inner surface of the sealing plate (29) so as to surround the through-conduit (5), and the second sealing layer (31) extends the secondary sealing membrane (8) up to the sealing plate (29).

3. 3. The sealed insulated tank (1) according to claim 2, wherein the second sealing layer (31) comprises at least two sealing strips (31 a, 31 b), each of which is arranged across two adjacent secondary insulating blocks (17).

4. 4. The sealed insulated tank (1) according to claim 3, wherein the two sealing strips (31 a, 31 b) of the second sealing layer (31) are aligned with each other on both sides of the through-conduit (5) so as to cover the spaces (42 a, 42 b).

5. 5. The sealed insulated tank (1) according to claim 3 or 4, wherein the two sealing strips (31 a, 31 b) of the second sealing layer (31) are positioned perpendicular to the at least one interface portion (47) of the first primary insulation block (35) and the at least one interface portion (47) of the second primary insulation block (35).

6. The tank wall (2) comprises two prefabricated panels (10a, 10b) arranged on both sides of the through-pipe (5), each of which comprises a lower insulating block (17) forming a secondary insulating block (17), the first sealing layer (20) covering the secondary insulating block (17), and an upper insulating block (21a, 21b) arranged in the central region between the first sealing layer (20) and the lower insulating block (21a, 21b) without covering the peripheral region of the first sealing layer (20).

4. The sealed insulated tank (1) according to claim 2 or 3, further comprising an upper insulating block (21 a, 21 b) which is part of the primary insulating barrier (6), and the primary insulating block (35) is arranged between the upper insulating blocks (21 a, 21 b) of the two prefabricated panels (10 a, 10 b) on the outer periphery of the first sealing layer (20) of the two prefabricated panels (10 a, 10 b) and on the space (42 a, 42 b).

7. 7. The sealed insulated tank according to claim 6, wherein the primary sealing membrane (6) comprises sealing plates (48) tightly connected to each other at their edges (100), the upper insulating blocks (21 a, 21 b) of the two prefabricated panels (10 a, 10 b) comprise fastening strips (43) for the edges (100) of the sealing plates (48) to fasten the sealing plates (48) to the prefabricated panel (10 a), and the primary insulating block (35) comprises thermal insulation strips (50) for the edges (100) of the sealing plates (48) so that the sealing plates (48) are not fastened to the primary insulating block (35).

8. 4. The sealed insulated tank (1) according to claim 1, wherein the primary sealing membrane (6) comprises at least one series of corrugations (38 a, 38 b) extending along parallel directrixes, the corrugations (38 a, 38 b) projecting towards the inside of the sealed insulated tank (1), at least one directrix of a given corrugation (38 a, 38 b) of the series of corrugations is interrupted by a window (49), the corrugations (38 a, 38 b) preferably have an open end at the window (49), and the sealed insulated tank (1) has at least one end piece (52) for closing the open end of at least one corrugation (38 a, 38 b).

9. 4. The sealed insulated tank (1) according to claim 1, wherein the outer conduit (27, 28) comprises a first circumferential connecting plate (27) and a second circumferential connecting plate (28), the second circumferential connecting plate (28) being tightly fixed to the first circumferential connecting plate (27) around the entire periphery of the first circumferential connecting plate (27), the first circumferential connecting plate (27) extending from the second circumferential connecting plate towards the outside of the sealed insulated tank (1) parallel to the through conduit (5), and the second circumferential connecting plate (28) being tightly fixed to the sealing plate (29) and projecting towards the load-bearing structure (3) parallel to the through conduit (5).

10. 4. The sealed insulated tank (1) according to claim 1, wherein the tank wall (2) also has at least one closing plate (51), which is arranged in the primary insulating block (35) so as to surround the through-pipe (5) and is tightly connected to the through-pipe (5).

11. A sealed insulated tank (1) as claimed in claim 8, wherein the tank wall (2) also has at least one closure plate (51), which is arranged on the primary insulation blocks (35) so as to surround the through-pipe (5) and is tightly connected to the through-pipe (5), at least one of the primary insulation blocks (35) has at least one slot (57), and the closure plate (51) has at least one slot (69), which is covered by an end piece (52) and overlaps the slot (57) of the primary insulation block (35), thereby allowing inert gas to flow between the corrugations (38a, 38b) and the outer conduit.

12. 11. The sealed insulated tank (1) according to claim 10, wherein the tank wall (2) comprises a heat insulating sheet (72) interposed between the primary insulating block (35) and the closing plate (51).

13. 4. The sealed insulated tank (1) according to claim 1, wherein the through conduit (5) forms a passage between the inside of the sealed insulated tank (1) and a steam manifold arranged outside the sealed insulated tank (1).

14. 1. A ship (58) used for transporting cryogenic liquid products, the ship (58) having a double hull (59) and a sealed insulated tank (1) according to any one of claims 1 to 3 arranged inside the double hull (59).

15. 15. Use of a vessel (58) according to claim 14 for loading or unloading a cryogenic liquid product, wherein the cryogenic liquid product is transferred from an onshore or floating storage facility (63) through an insulating pipe (66) to the sealed insulated tank (1) provided on the vessel (58), or transferred from the sealed insulated tank (1) provided on the vessel (58) to an onshore or floating storage facility (63) through an insulating pipe (66).

16. 15. A transfer system for cryogenic liquids, comprising: a vessel (58) according to claim 14; an insulating pipe (66) arranged to connect the sealed insulated tank (1) installed within the hull of the vessel (58) to an onshore or floating storage facility (63); and a pump for pumping a cryogenic liquid product stream from the onshore or floating storage facility (63) through the insulating pipe (66) to the sealed insulated tank (1) installed on the vessel (58) or from the sealed insulated tank (1) installed on the vessel (58) through the insulating pipe (66) to the onshore or floating storage facility (63).

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