Tank wall

Abstract

The invention relates to a tank wall for forming a sealed and thermally insulating tank for storing liquefied gas, the tank wall resting against a support surface and comprising a sealing membrane and a thermally insulating barrier arranged between the sealing membrane and the support surface, the thermally insulating barrier comprising a row of standard insulating blocks and a row of end boxes spaced from the row of standard insulating blocks in a longitudinal direction of the tank wall by an inter-block space;The row of standard insulating blocks and the row of end boxes extending in a transverse direction of the tank wall perpendicular to the longitudinal direction, the tank wall further comprising a metal structure extending between the sealing membrane and the support surface in the thickness direction to hermetically seal a space between the sealing membrane and the support surface, the metal structure extending along the end boxes and terminating the tank wall in the longitudinal direction; the metal structure being hermetically fixed on one side to the support surface and, on the other side, to the sealing membrane; the tank wall further comprising at least one wedge positioned in the inter-block space; at least one wedge extending along the longitudinal direction of the tank wall, between a standard insulating block and an end box. Figure for the abbreviation: 2;

Description

Title of the invention: Tank wall technical field

[0001] The invention relates to the field of tank walls to form a sealed and thermally insulated tank for the storage of liquefied gas.

[0002] In particular, the invention relates to the field of tank walls for forming leak-proof and thermally insulated tanks for the storage and / or transport of low-temperature liquids, such as tanks for transporting Liquefied Petroleum Gas (also called LPG) with a temperature between -50°C and 0°C, or for transporting Liquefied Natural Gas (LNG) at approximately -162°C at atmospheric pressure. These tanks can be installed on land or on a floating structure.

[0003] In the case of a floating structure, the tank may be intended for the transport of liquefied gas or for receiving liquefied gas used as fuel for the propulsion of the floating structure. Technological background

[0004] A sealed and thermally insulated liquefied natural gas storage tank arranged in a supporting structure has a multilayer structure, namely from the outside to the inside of the tank, a secondary thermally insulating barrier anchored against the supporting structure, a secondary sealing membrane which rests on the secondary thermally insulating barrier, a primary thermally insulating barrier which rests on the secondary sealing membrane and a primary sealing membrane which rests on the primary thermally insulating barrier and which is intended to be in contact with the liquefied natural gas stored in the tank.

[0005] During the manufacture of the tank, tests are carried out to ensure the tightness of the secondary sealing membrane or the primary sealing membrane.

[0006] For example, during the manufacture of a methane tanker, a lateral opening is sealed at the end of the tank manufacturing process by adding a section of the supporting structure onto which a section of the tank is mounted. It is then common practice to independently check the watertightness of the sealing membrane of the section of the tank outside the area of ​​the lateral opening, and then of the entire sealing membrane, including the added section of the tank.

[0007] However, such a leak test of the sealing membrane of a section of the tank is complex and requires numerous manipulations and checks. In particular, because this test is only carried out on an unfinished section of the tank, the sealing membrane does not form a closed, airtight space allowing for a simple and direct leak test.

[0008] To form such a sealed closed space in the portion of the tank to be tested, it is known to position temporary insulation panels at the end of the insulating barrier on which rests the sealing membrane for which a leak test is carried out.

[0009] For example, document KR10-2015-0067685 describes, in [Fig.3], a temporary insulation panel for the LNG side opening comprising a first insulation panel, a second insulation panel, an upper deck panel, insulation material and a temporary heat dissipation panel.

[0010] Then, a sealing structure, for example a metal structure, is fixed in a watertight manner along the temporary insulation panels, on the one hand, to a support surface of the insulating barrier of the portion of the tank to be tested and, on the other hand, to the sealing membrane of the portion of the tank to be tested.

[0011] During the leak test, the portion of the tank to be tested is depressurized. A force is then exerted on the temporary insulation panels. This force is due to the depressurization of the sealed enclosed space. This force is therefore exerted on the walls of the insulation panels inside the sealed enclosed space and is directed towards the interior of the sealed enclosed space, i.e., towards the current insulation blocks of the insulating barrier.

[0012] This force can cause the temporary insulation panels to tip towards the regular insulation blocks and damage the waterproof membrane resting on the insulating barrier.

[0013] Generally, the insulation material positioned between the current insulation blocks of the insulating barrier and the temporary insulation panels prevents or limits such tipping.

[0014] However, once the leak test has been carried out, the removal of the temporary insulation panels often renders unusable the insulation material placed between the temporary insulation panels and the regular insulation blocks.

[0015] This therefore results in a loss of insulating material.

[0016] The invention aims, in particular, to prevent damage to the waterproof membrane during its leak test while avoiding the loss of insulating material. The invention also aims to simplify the installation of the insulation in the temporary zone, thereby saving time during installation. Summary of the invention

[0017] One idea underlying the invention is to provide an element for taking back the stresses suffered by the common insulating blocks when the closed sealed space is depressurized, other than the insulating material.

[0018] Another idea underlying the invention is to save insulation material when depressurizing the sealed enclosed space.

[0019] Another idea underlying the invention is to simplify and reduce the assembly and disassembly time of the temporary area.

[0020] For this purpose, according to one embodiment, the invention provides a tank wall to form a sealed and thermally insulated tank for storing liquefied gas, the tank wall resting against a support surface and comprising a sealing membrane and a thermally insulating barrier arranged between the sealing membrane and the support surface, the thermally insulating barrier comprising a row of standard insulating blocks and a row of end boxes spaced from the row of standard insulating blocks in a longitudinal direction of the tank wall by an inter-block space; the row of standard insulating blocks and the row of end boxes extending in a transverse direction of the tank wall perpendicular to the longitudinal direction;the tank wall further comprising a metal structure extending between the sealing membrane and the support surface in a direction corresponding to the thickness of the tank wall in order to hermetically seal a space between the sealing membrane and the support surface, the metal structure extending along the end boxes and terminating the tank wall in the longitudinal direction; the metal structure being hermetically fixed on one side to the support surface and, on the other side, to the sealing membrane; the tank wall further comprising at least one wedge positioned in the inter-block space; at least one wedge extending along the longitudinal direction of the tank wall, between a standard insulating block and an end box.

[0021] Thanks to these characteristics, the wedge protects the standard insulating blocks by withstanding the stresses generated on them during the leak test. Thus, the standard insulating blocks are not damaged during the leak test.

[0022] Furthermore, the shim eliminates the need to install insulating material between the standard insulating blocks and the end boxes during the leak test. This prevents the loss of insulating material and saves on assembly time.

[0023] According to embodiments, such a tank may include one or more of the following characteristics.

[0024] According to one embodiment, the metal structure delimits an opening interrupting the tank wall in the longitudinal and transverse direction.

[0025] The end boxes are then positioned around the opening, for example a breach in the side of the tank under construction.

[0026] According to one embodiment, a dimension of the end boxes along the longitudinal direction is smaller than a dimension of the standard insulating blocks along the longitudinal direction. For example, the dimension of the end boxes along the longitudinal direction is less than or equal to one-quarter of the dimension of the standard insulating blocks along the longitudinal direction.

[0027] In this case, the dimensions of the end boxes along the thickness direction of the tank wall can be three to five times greater than the dimensions of the end boxes along the longitudinal direction. Thus, a tilting of the end boxes within the inter-block space is more likely to occur. The shim is therefore all the more important to prevent such a tilting.

[0028] According to one embodiment, an upper surface, along the thickness direction of the tank wall, of which at least one wedge is flush with an upper surface of said current insulating block or an upper surface of said end box.

[0029] The wedge is thus located at the upper end of the inter-block space along the thickness direction of the tank wall. For example, the wedge is against the end cap of a standard insulating block. The reaction force exerted by the wedge is therefore at its maximum. Tilting of the end block against which the wedge rests is thus more easily prevented during the leak test.

[0030] According to one embodiment, at least one wedge is fixed to said end box and abutted against said current insulating block.

[0031] The wedge can then be fixed to the end box prior to the placement of the end box opposite the current insulating block.

[0032] According to one embodiment, the at least wedge comprises a wedge foot and a wedge body, the wedge foot being fixed to said end box and the wedge body being abutted against said current insulating block, for example abutted against a cover of a current insulating block (not shown).

[0033] According to one embodiment, the bilge body has a smaller dimension than the bilge foot in the thickness direction of the tank wall so as to form a clearance adjacent to an upper portion of the bilge foot;

[0034] The clearance allows an operator to secure the wedge against the end box.

[0035] Alternatively, it is also possible that the wedge foot is fixed to said insulating block and the wedge body is abutted against said current end box.

[0036] According to one embodiment, the clearance defines a free space between the sealing membrane and the bilge body.

[0037] The wedge can be made in different ways and in different geometric shapes. For example, an inverted L of 90° or 180° by rotation, a cube or even a rectangular prism.

[0038] According to one embodiment, the wedge is formed from a single block comprising both the wedge foot and the wedge body. In other words, the wedge comprises only one single part comprising both the wedge foot and the wedge body.

[0039] According to one embodiment, the wedge foot is a first part of the wedge and the wedge body is a second part distinct from the first part; the first part and the second part being fixed to each other.

[0040] According to one embodiment, at least one wedge is only fixed to said end box.

[0041] Thus, the current insulating block is not altered by the placement of the wedge between a current insulating block and an end box.

[0042] According to one embodiment, the sealing membrane comprises a continuous sheet of metal strakes with raised edges; a longitudinal direction of the metal strakes with raised edges corresponding to the longitudinal direction of the tank wall.

[0043] According to one embodiment, the sealing membrane comprises a continuous sheet of metal strakes with at least one undulation; a longitudinal direction of the metal strakes with at least one undulation corresponding to the longitudinal direction of the tank wall.

[0044] According to one embodiment, the tank wall further comprises a plurality of anchoring devices retaining the current insulating blocks and the end boxes against the support surface; the anchoring devices being positioned in the inter-block space, at least one wedge being disposed between said anchoring devices in the transverse direction.

[0045] According to one embodiment, the tank wall comprising a plurality of wedges positioned between the anchoring devices in the transverse direction.

[0046] According to one embodiment, the inter-block space includes at least one free space extending along the transverse direction of the tank wall between a said wedge and one of said anchoring devices.

[0047] The shim does not extend over the entire thickness of the inter-block space. Generally, the inter-block space is filled with insulating material. The shim allows the space between the shim and one of the anchoring devices to remain free. This represents a saving of time during assembly and disassembly, as well as of insulating material.

[0048] According to one embodiment, the inter-block space includes at least one free space which extends between at least one wedge and the support surface along the thickness direction of the tank wall.

[0049] According to one embodiment, the inter-block space comprises at least one free space extending between at least one wedge and the tank support surface. This free space is devoid of insulating material.

[0050] Similarly, the space between the blocks is generally filled with insulating material. The shim allows the space between at least one shim and the support surface to remain free. This saves time during assembly and disassembly and reduces the need for insulating material.

[0051] According to one embodiment, the thermally insulating barrier is a secondary thermally insulating barrier, the sealing membrane is a secondary sealing membrane, the tank wall further comprising a primary sealing membrane intended to delimit an interior space of the tank and a primary thermally insulating barrier arranged between the primary sealing membrane and the secondary sealing membrane.

[0052] According to one embodiment, the support surface is a load-bearing wall of the tank. According to another embodiment, the support surface is a secondary sealing membrane.

[0053] According to one embodiment, the support surface is a load-bearing wall and the load-bearing structure has an opening, the tank wall being terminated by the metal structure near the opening.

[0054] According to another aspect, the invention provides a sealed and thermally insulating liquefied gas storage tank, comprising a tank wall according to one of the embodiments.

[0055] According to another aspect, the invention provides a vessel for the transport of a cold liquid product, the vessel comprising a double hull and a sealed and thermally insulated tank according to one of the embodiments arranged in the double hull.

[0056] According to another aspect, the invention provides a transfer system for a cold liquid product, the system comprising a vessel according to one of the embodiments, insulated pipes arranged to connect the vessel's tank to a floating or land-based storage facility and a pump to drive a flow of cold liquid product through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

[0057] According to another aspect, the invention provides a method for loading or unloading a ship according to one of the embodiments, in which a cold liquid product is conveyed through insulated pipes from or to a floating or land-based storage facility to or from the ship's tank. Brief description of the figures

[0058] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent in the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the attached drawings.

[0059] Fig. 1 schematically represents a perspective view of one end of a tank wall.

[0060] Fig. 2 schematically represents a perspective view of one end of a tank wall according to Fig. 1 in which the sealing membrane is omitted.

[0061] The [Fig.3] is seen in section along plane AA of the [Fig.2].

[0062] [Fig.4] is an enlarged view of area IV of [Fig.3].

[0063] The [Fig.5] is seen in section along plane BB of the [Fig.2].

[0064] Figure 6 is a schematic cutaway representation of a ship's tank LNG carrier and a loading / unloading terminal for this tank. Description of the implementation methods

[0065] By convention, the terms "lower" and "upper" are used to define the relative position of one element with respect to another, respectively in the direction of the outside or the inside of the tank, i.e. along a thickness direction of the tank, as in the horizontal wall shown in [Fig. 1]. However, the following description is applicable to any wall regardless of its orientation in the Earth's gravitational field.

[0066] In [Fig. 1], a tank wall 1 is shown to form a sealed and thermally insulated tank for storing liquefied gas. The tank wall 1 extends in a longitudinal direction L of the wall between at least two longitudinal ends and in a transverse direction T, perpendicular to the longitudinal direction L, between at least two transverse ends.

[0067] By convention, the longitudinal direction L of the tank wall 1 is perpendicular to a transverse direction T of the tank wall 1. A thickness direction e is orthogonal to the transverse direction T and longitudinal direction L and defines the thickness of the wall from the outside of the tank to the inside of the tank.

[0068] [Fig.1] illustrates an area of ​​the tank wall 1 to which a longitudinal end L1 is reached by the tank wall 1. Similarly, in [Fig.1], a transverse end T1 is reached by the tank wall.

[0069] Furthermore, [Fig. 1] illustrates an opening 1000 in the tank. This opening 1000 is a particular example where the tank wall 1 reaches a longitudinal end L1 and a transverse end TL. However, there are other areas of the tank wall 1 - not shown - in which the tank wall 1 reaches a longitudinal end and / or a transverse end.

[0070] The opening 1000 is thus delimited by a longitudinal end of the tank wall and / or a transverse end of the tank wall.

[0071] For example, opening 1000 corresponds to a lateral portion of the corresponding tank, left open to allow the passage of tools necessary for the tank's construction. This opening 1000, generally called a hull breach, is closed to finalize the tank's construction by attaching a portion of the tank's load-bearing structure onto which a corresponding tank wall is mounted. As another example, opening 1000 corresponds to a portion of the corresponding tank's ceiling, left open to allow the passage of a loading / unloading mast structure.

[0072] The tank wall 1 rests against a support surface 100. The support surface 100 may be a load-bearing wall of the tank, as illustrated in the figures. However, if the tank comprises a primary layer and a secondary layer, the support surface 100 may then be a sealing membrane for the secondary layer.

[0073] The tank wall includes a sealing membrane 3 and a thermally insulating barrier 2 arranged between the sealing membrane 3 and the support surface 100.

[0074] As illustrated in [Fig. 1], the sealing membrane 3 comprises a continuous sheet of metal strakes with raised edges 800. A longitudinal direction of the metal strakes with raised edges corresponds to the longitudinal direction of the tank wall 1. The metal strakes with raised edges 800 are periodically spaced along the tank wall 1 in the transverse direction of the tank wall 1.

[0075] The thermally insulating barrier 2 comprises a plurality of common insulating blocks 21 extending in successive rows in the longitudinal and transverse directions of the tank wall 1. The common insulating blocks 21 each form the elementary unit of the wall repeating in the longitudinal and transverse directions of the tank wall 1.

[0076] According to an exemplary embodiment illustrated in [Fig. 3], each common insulating block 21 comprises a lower block 211, resting against the support surface 100 by means of a base plate 2111, and an upper block 212 resting against a cover 2112 of the lower block 211 by means of a base plate 2121. The upper block 212 comprises a cover 2122 forming a cover for the common insulating block 21. The upper block 212 does not completely cover the upper surface of the lower block 211, so that a shoulder 2110 is left free and protrudes in the longitudinal direction relative to the upper block 212.

[0077] Alternatively, and not shown, one or more of the current insulating blocks 21 may be monolithic, i.e., comprise only a single block extending between the base plate 2111 and the cover 2122. This single block comprises an insulating material, for example, polyurethane foam. In this case, the base plate 2121 and the cover 2112 are omitted.

[0078] Furthermore, in [Fig.3], strips of sealant 214 are arranged between the lower block 211 and the support surface 100.

[0079] According to another embodiment illustrated in Figures 1 and 2, the common insulating blocks 21 may comprise a single block made with a composite structure or of wood plywood. The structure may include an internal stiffener structure as shown in publication FR2867831.

[0080] The standard insulating blocks 21 are filled with an insulating lining, for example glass wool or perlite or polyurethane foam.

[0081] The thermally insulating barrier 2 also includes a plurality of end boxes 22 positioned at the longitudinal and transverse ends of the tank wall 1. Each end box 22 is a rectangular block extending between a bottom wall 221 and a lid 222. Two side walls 225 connect the bottom wall 221 and the lid 222. A larger dimension of the common insulating blocks 21 extends in the longitudinal direction.

[0082] If the longitudinal and transverse ends of the tank wall 1 define an opening 1000 in the tank wall, then the end boxes 22 being positioned near the longitudinal end of the tank wall defining the opening, the end boxes 22 are positioned near the opening 1000, for example at a distance corresponding to one fifth or one quarter of a longitudinal or transverse dimension of a standard insulating block 21.

[0083] In [Fig. 1], an end box 22 is positioned opposite two current insulating blocks 21 at the longitudinal end LL. A larger dimension of the end boxes 22 extends in the transverse direction.

[0084] Thus, by generalization along the transverse direction of the tank wall 1, at the longitudinal end Ll, a row of standard insulating blocks 21 extends in the transverse direction of the tank wall 1 opposite a row of end boxes 22 also extending in the transverse direction of the tank wall 1.

[0085] Similarly, in [Fig. 1], an end box 22 is positioned opposite a current insulating block 21 at the transverse end TL

[0086] As illustrated in Figures 1 and 2, one dimension, along the longitudinal direction of the tank wall 1, of the end boxes 22 is less than one dimension, along the longitudinal direction of the tank wall 1, of the common insulating blocks 22. The ratio between the dimension D, along the longitudinal direction of the tank wall 1, of the end boxes 22 and the dimension d, along the longitudinal direction of the tank wall 1, of the common insulating blocks 22 is between one tenth (1 / 10) and one quarter (1 / 4).

[0087] As illustrated in [Fig. 1] and 2, the common insulating blocks 21 and the end boxes are fixed to the support surface 100 by anchoring devices 6. The anchoring devices 6 bear on cleats 200 fixed to the common insulating blocks 21 and the end boxes 22.

[0088] In addition, the end boxes 22 are spaced from the current insulating blocks 21 in a longitudinal direction of the tank wall by an inter-block space 60.

[0089] The inter-block space 60 extends, in the longitudinal direction, from a longitudinal end of the row of common insulating blocks 21 to a longitudinal end of the row of end boxes 22. In the transverse direction, the inter-block space 60 extends along the smallest dimension of the common insulating blocks 21.

[0090] The sealing membrane 3 covers the inter-block space 60 and rests on both the row of common insulating blocks 21 and the row of end boxes 22. With respect to the common insulating block 21, the sealing membrane 3 rests on a cover of each common insulating block 21. Similarly, the sealing membrane 3 rests on a cover 222 of an end box 22.

[0091] The anchoring devices 6 are positioned in the inter-block space 60 at regular intervals.

[0092] Outside the end zone illustrated in [Fig. 1], according to one embodiment, the anchoring devices 6 are positioned at the four corners of the standard insulating blocks 21. Each standard insulating block 21 is anchored to the support surface 100 by means of four anchoring devices 6. In addition, each anchoring device 6 cooperates with the corners of four adjacent insulating blocks 21. As shown in [Fig. 5], a rod of an anchoring device 6 is then inserted into an insulating piece 90. This embodiment is described in FR2005545 according to several possible variations.

[0093] Within the inter-block space 60, the anchoring devices 6 are preferably positioned at the corners of two adjacent common insulating blocks 21 and of an end box 22 opposite these two common insulating blocks 21. Each anchoring device 6 is also inserted into an insulation piece 90.

[0094] According to an embodiment illustrated in [Fig.5], each anchoring device 6 is supported against the shoulder of the block 2110 on one side and, on the other side, against the cleat 200 of the end box 22.

[0095] During the manufacture of the tanks, it is necessary to test the leak-tightness of the sealing membrane during the manufacturing process. Therefore, in order for the tank wall 1 to form a sealed, enclosed space allowing for a simple and direct leak-tightness test, the tank wall 1 further comprises a metal structure 4 extending between the sealing membrane 3 and the support surface bearing the thermally insulating barrier 2 in the thickness direction. The membrane sealing 3, covering the inter-block space 60, and the metal structure 4 allow a sealed closed space to be formed in the tank wall 1.

[0096] The metal structure 4 extends along the end boxes 22 and is fixed in a watertight manner on one side to the support surface 100 and, on the other side, to the sealing membrane 3.

[0097] The metal structure 4 thus makes it possible to seal in a watertight manner a space between the sealing membrane 3 and the support surface 100.

[0098] As illustrated in the figures, the metal structure 4 comprises a central portion 41 from which upper extremity portions 42 and lower extremity portions 43 extend perpendicularly. The central portion 41 extends against a lateral wall 225 of each end box 22 along the thickness direction e. The upper extremity portions 42 and lower extremity portions 43 extend in opposite directions along the longitudinal direction L. The upper extremity portion 42 is fixed watertight along the sealing membrane 3 and the lower extremity portion 43 is fixed watertight along the support surface 100.

[0099] The enclosed sealed space is thus delimited by the support surface 100, the sealing membrane 3 and the metal structure 4.

[0100] With reference to figures 2 and 3, the tank wall 1 further includes at least one wedge 5 positioned in the inter-block space 60.

[0101] The wedge 5 extends along the longitudinal direction of the tank wall 1, between a common insulating block 21 of the row of common insulating blocks and an end box 22 of the row of end boxes.

[0102] As illustrated in [Fig. 2], the wedge 5 is positioned in the inter-block space between two consecutive anchoring devices 6. Furthermore, several wedges 5 can be positioned between two consecutive anchoring devices 6. For example, two wedges 5 are positioned between two consecutive anchoring devices 6.

[0103] With reference to [Fig.3], the wedge 5 is fixed to said end box 22 and abutted against said current insulating block 21. Thus, the wedge 5 prevents the end box 22 from tilting towards the insulating block 21, in the longitudinal direction L, under the effect of the forces resulting from the depressurization of the sealed space during the leak test.

[0104] The wedge 5 is fixed by any means to the end box 22. For example, two rows of two screws or staples or nails, i.e. four screws, staples or nails, fix the wedge 5 to the end box 22.

[0105] In one embodiment, the wedge 5 is only fixed to the end box 22.

[0106] The wedge 5 has a general inverted L shape at 90°. It comprises a wedge foot 51 and a wedge body 52 forming an inverted L at 90°. The wedge body 52 has a smaller dimension than the wedge foot 51 in the thickness direction. of the tank wall 1 so as to form a clearance adjacent to an upper portion of the foot of the bilge 51.

[0107] The wedge foot 51 being fixed to said end box 22 and the wedge body 52 being abutted against said current insulating block 21.

[0108] As illustrated in [Fig. 4], the wedge foot 51 is a first part and the wedge body 52 is a second part distinct from the first part. The first part 51 and the second part 52 are fixed to each other.

[0109] However, the wedge 5 can be formed from a block having, for example, a general L-shape.

[0110] In addition, in [Fig.3], the wedge foot 51 is fixed to the end box 22 and the wedge body 52 is abutted against the said current insulating block 21.

[0111] The wedge 5 can be positioned at any height of the inter-block space, for example in contact with the cover 2122 of the upper block 212. However, in the embodiment illustrated in [Fig.4], an upper surface 500 of the wedge 5 is flush with an upper surface 220 of the end box 22.

[0112] Thus, a clearance 63 is left free between the sealing membrane 3 and the bilge body 52.

[0113] Furthermore, the positioning of the wedge 5 between two anchoring devices 6 in the inter-block space 60 delimits a plurality of first free spaces 61 and a plurality of second free spaces 62.

[0114] Each of the first free space 61 and second free space 62 is said to be free in that it does not contain insulating material, anchoring device 6 or wedge 5.

[0115] As illustrated in [Fig.2], the first free spaces 61 extend on either side of the wedge 5 in the transverse direction of the tank wall 1. In other words, the first free spaces 1 extend between the wedge 5 and each of the two consecutive anchoring devices 6 located on either side of the wedge 5 in the transverse direction of the tank wall 1.

[0116] As illustrated in [Fig.3], the second free spaces 62 extend vertically from the wedge 5, i.e. in the thickness direction e of the tank wall 1, from a lower surface 501 of the wedge 5 to the support surface 100.

[0117] The tank wall 1 described above may comprise a single thermally insulating barrier 2 and a single sealing membrane 3. In this case, the support surface is a load-bearing wall of the tank and the sealing membrane 3 is intended to be in contact with the liquefied natural gas contained in the tank.

[0118] The sealed enclosed space is thus delimited by the load-bearing wall of the tank, the sealing membrane 3 and the metal structure 4.

[0119] It is also possible that the tank has a multilayer structure. In this case, the tank wall 1 comprises successively, in the thickness direction, from from the outside to the inside of the tank, a secondary thermally insulating barrier held to a load-bearing wall, a secondary airtight membrane resting against the secondary thermally insulating barrier, a primary thermally insulating barrier resting against the secondary airtight membrane and a primary airtight membrane intended to be in contact with the liquefied natural gas contained in the tank.

[0120] In this case, the thermally insulating barrier 2 is the secondary thermally insulating barrier, the sealing membrane 3 is the secondary sealing membrane, the common insulating blocks are secondary common insulating blocks; the end boxes are secondary end boxes and the wedge is a secondary wedge and the inter-block space is a secondary inter-block space, the thermally insulating barrier 2 and the sealing membrane 3 then form the secondary layer of the tank.

[0121] The support surface 100 is then a load-bearing structure of the tank wall 1 to which the tank wall 1 is fixed.

[0122] The primary layer includes the primary thermally insulating barrier resting against the secondary sealing membrane and the primary sealing membrane intended to be in contact with the liquefied natural gas contained in the tank.

[0123] The primary layer can be constructed in a manner analogous to the secondary layer or be constructed differently.

[0124] Leak test and advantages of wedge 5

[0125] The above description is indicated for testing the tightness of a sealing membrane, i.e. the tightness of the closed sealed space formed as just described.

[0126] In order to test the leak tightness of the sealing membrane 3 to be tested, the sealed enclosed space is connected to a vacuum means. Such a vacuum means is, for example, a vacuum pump connected to the sealed enclosed space or any other vacuum means capable of reducing the pressure in the sealed enclosed space.

[0127] Activating the vacuum device reduces the pressure within the sealed enclosure relative to the external environment. This vacuum is, for example, on the order of -200 to -500 mbar absolute. The test is performed for 10 to 48 hours, and the pressure variation is recorded to determine if any leaks are present.

[0128] When the sealed enclosed space is depressurized, the end box 22 is subjected to a force directed towards the current insulating block 21 due to the pressure difference between the sealed enclosed space and the environment outside said sealed enclosed space. This force may not be completely compensated by the weight of the end box 22 given the small size of the end box 22 in the longitudinal direction L.

[0129] The wedge 5 resting against the current insulating block 21 and fixed against the end box 22 so that the end box 22 is prevented from tilting towards the current insulating block 21 in the inter-block space 60.

[0130] In addition, the wedge 5 makes it possible not to fill the inter-block space 60 with insulating material to ensure the retention of the end box 22 during the leak test.

[0131] In short, wedge 5 allows for a saving of time and a saving of insulating material.

[0132] Other

[0133] With reference to [Fig. 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 vessel. The wall of the tank 71 comprises a primary watertight barrier intended to be in contact with the LNG contained in the tank, a secondary watertight barrier arranged between the primary watertight barrier and the double hull 72 of the vessel, 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.

[0134] In a manner known per se, loading / unloading pipelines 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a marine or port terminal or to an LNG bunker ship to transfer an LNG cargo to or from the tank 71.

[0135] Figure 6 shows an example of a marine terminal comprising a loading and unloading berth 75, a subsea pipeline 76 and an onshore installation 77. The loading and unloading berth 75 is a fixed offshore installation comprising a movable arm 74 and a tower 78 which supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipelines 73. The steerable movable arm 74 is suitable for all LNG carrier sizes. An unshown connecting pipeline extends inside tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore facility 77. This facility includes liquefied gas storage tanks 80 and connecting pipelines 81 linked by the subsea pipeline 76 to the loading or unloading station 75.The subsea pipeline 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore facility 77 over a long distance, for example 5 km, which allows the LNG carrier 70 to be kept a long distance from the coast during loading and unloading operations.

[0136] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the land installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0137] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0138] The use of the verb "comprise", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

[0139] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

Demands

1. Tank wall (1) for forming a sealed and thermally insulating liquefied gas storage tank, the tank wall resting against a support surface and comprising a sealing membrane (3) and a thermally insulating barrier arranged between the sealing membrane and the support surface, the thermally insulating barrier comprising a row of standard insulating blocks (21) and a row of end boxes (22) spaced from the row of standard insulating blocks (21) in a longitudinal direction of the tank wall by an inter-block space;the row of standard insulating blocks (21) and the row of end boxes (22) extending in a transverse direction of the tank wall perpendicular to the longitudinal direction, the tank wall further comprising a metal structure (4) extending between the sealing membrane and the support surface in a thickness direction of the tank wall in order to hermetically enclose a space between the sealing membrane and the support surface, the metal structure (4) extending along the end boxes and terminating the tank wall in the longitudinal direction; the metal structure being hermetically fixed on one side to the support surface and, on the other side, to the sealing membrane; the tank wall further comprising at least one wedge (5) positioned in the inter-block space;at least one wedge extending along the longitudinal direction of the tank wall, between a standard insulating block (21) and an end box (22).

2. Tank wall (1) according to the preceding claim, wherein the metal structure delimits an opening (1000) interrupting the tank wall in the longitudinal and transverse direction.

3. Tank wall (1) according to any one of the preceding claims, wherein a dimension (d) of the end boxes along the longitudinal direction is less than a dimension (D) of the current insulating blocks along the longitudinal direction.

4. Tank wall (1) according to any one of the preceding claims, wherein an upper surface (500), according to the direction of thickness of the tank wall, of the at least one shim (5) is flush with an upper surface (213) of said current insulating block or an upper surface (220) of said end box.

5. Tank wall (1) according to any one of the preceding claims, wherein at least one wedge (5) is fixed to said end box (22) and abutted against said current insulating block (21).

6. Tank wall (1) according to claim 5, wherein the at least one wedge (5) comprises a wedge foot (51) and a wedge body (52), the wedge foot (51) being fixed to said end box (22) and the wedge body (52) abutting said current insulating block (21). Tank wall (1) according to the preceding claim, wherein the wedge foot (51) is a first part (51) of the wedge (5) and the wedge body (52) is a second part (52) distinct from the first part; the first part (51) and the second part (52) being fixed to each other.

7. Tank wall (1) according to any one of the preceding claims, wherein at least one wedge (5) is only fixed to said end box.

8. Tank wall (1) according to any one of the preceding claims, wherein the sealing membrane comprises a continuous sheet of metal strakes with raised edges (800); a longitudinal direction of the metal strakes with raised edges corresponding to the longitudinal direction of the tank wall.

9. Tank wall (1) according to any one of the preceding claims, further comprising a plurality of anchoring devices (6) retaining the current insulating blocks (21) and the end boxes (22) against the support surface; the anchoring devices being positioned in the inter-block space, at least one wedge being disposed between said anchoring devices (6) in the transverse direction.

10. Tank wall (1) according to the preceding claim, wherein the inter-block space (60) comprises at least one free space (61) extending along the transverse direction of the tank wall between said wedge and one of said anchoring devices.

11. Tank wall (1) according to any one of the preceding claims, wherein the inter-block space (60) comprises at less a free space (62) which extends between at least one wedge and the support surface along the thickness direction of the tank wall.

12. Tank wall (1) according to any one of the preceding claims, wherein the thermally insulating barrier (2) is a secondary thermally insulating barrier, the sealing membrane (3) is a secondary sealing membrane, the tank wall further comprising a primary sealing membrane intended to delimit an interior space of the tank and a primary thermally insulating barrier arranged between the primary sealing membrane and the secondary sealing membrane.

13. Tank wall (1) according to any one of the preceding claims, wherein the support surface is a load-bearing tank wall or a secondary sealing membrane.

14. Tank wall (1) according to any one of the preceding claims, wherein the support surface is a load-bearing wall, and wherein the load-bearing structure has an opening, the tank wall being terminated by the metal structure near the opening.

15. A sealed and thermally insulating liquefied gas storage tank comprising a tank wall according to any one of claims 1 to 15.

16. Vessel (70) for the transport of a cold liquid product, the vessel comprising a double hull (72) and a watertight and thermally insulating tank according to claim 16 disposed in the double hull.

17. Transfer system for a cold liquid product, the system comprising a vessel (70) according to claim 17, insulated pipes (73, 79, 76, 81) arranged to connect the vessel's tank (71) to a floating or land-based storage facility (77) and a pump to drive a flow of cold liquid product through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

18. A method of loading or unloading a ship (70) according to claim 17, wherein a cold liquid product is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or land-based storage facility (77) to or from the ship's tank.

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