Waterproof and thermally insulating tank

Abstract

The invention relates to a sealed and thermally insulating tank (71) comprising a tank wall (1) and a through-member (5) passing through the tank wall (1). A sealing membrane (4) has a polygonal window (24) surrounding the through-member (5) to allow the through-member (5) to pass through. The sealing membrane (4) comprises a plurality of membrane portions juxtaposed and welded to each other, the plurality of membrane portions comprising at least one regular membrane portion (68, 69), the regular membrane portion (68, 69) having a series of parallel first corrugations (11) and a series of parallel second corrugations (12). Two corrugations (16, 18) among the second corrugations (12) are absent from singular rectangular metal sheets (51, 251, 61) arranged on either side of the window (24). Figure for abstract: Fig. 3

Description

Title of the invention: Sealed and thermally insulating tank Technical field

[0001] The invention relates to the field of sealed and thermally insulating membrane tanks. In particular, the invention relates to the field of sealed and thermally insulating tanks for the storage and / or transport of low-temperature liquefied gas, such as tanks for the transport of Liquefied Petroleum Gas (also called LPG) having, for example, a temperature between -50°C and 0°C, or for the transport of Liquefied Natural Gas (LNG) at approximately -162°C at atmospheric pressure. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank can 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

[0002] It is known from document WO 2011 / 157915 A1 sealed and thermally insulating tanks for the storage and / or transport of liquefied gas comprising at least one sealing membrane which is in contact with the liquefied gas. These tanks can be equipped with a loading / unloading tower or more simply with loading and unloading pipes passing through the ceiling wall of the tank to reach the internal space of the tank in order to load or unload the tank with liquefied gas.

[0003] In the case of a loading / unloading tower, this comprises a structure formed of several masts connected at a lower end to each other using a base. The loading / unloading tower further comprises a guide device which is fixed against the lower face of the base and which cooperates with a support foot which passes through the bottom wall of the tank and is fixed to the supporting structure.

[0004] Pumps, in particular unloading pumps, are fixed inside the tank to the loading / unloading tower, to the loading and unloading pipes or to the support foot. In order to limit the volume of liquid that cannot be discharged from the tank, the lower end of the unloading pump is located as close as possible to the sealing membrane at a predefined distance, of the order of a few centimeters.

[0005] Furthermore, in WO 2011 / 157915 A1, the sealing membrane in contact with the liquefied gas is a corrugated metal sealing membrane having a first series of parallel corrugations in a first direction and a second series of parallel corrugations in a second direction.

[0006] In document WO 2023 / 094330 A1, it was proposed to have on the waterproofing membrane an area devoid of one of the series of undulations at the right of the unloading pump, the absence of the undulations of this series of undulations in this area allowing the spacing between the sealing membrane and the internal element to be adapted in order to optimize the pumped volume.

[0007] However, the design of the waterproofing membrane in the document WO 2023 / 094330 A1 leads to the production of corrugated metal sheets on which a corrugation of this series of corrugations remains. Such corrugated metal sheets are difficult and expensive to produce. Summary

[0008] An idea behind the invention is to ensure that the waterproofing membrane can be manufactured simply and at a moderate cost, thanks to the arrangement of the corrugated metal sheets.

[0009] According to one embodiment, the invention provides a sealed and thermally insulating tank integrated in a supporting structure comprising a supporting wall, said tank comprising a tank wall fixed to the supporting wall of the supporting structure, in which the tank wall comprises, in a thickness direction from the outside to the inside of the tank, a thermally insulating barrier and a sealing membrane supported by the thermally insulating barrier and intended to be in contact with a fluid contained in the tank, the sealing membrane comprising a plurality of membrane portions juxtaposed and welded to each other, the plurality of membrane portions comprising at least one regular membrane portion, the regular membrane portion having a series of first parallel undulations extending in a first direction and spaced apart by a first wave pitch in a second direction, the second direction being orthogonal to the first direction, and a series of second parallel undulations extending in the second direction and spaced apart by a second wave pitch in the first direction, the tank comprising a through element passing through the tank wall, the through element being centered on the intersection between a first guideline extending in the first direction and located between directors of two of said first corrugations and a second guideline extending in the second direction and located between a first and a second of said second corrugations, the second guideline dividing the plane of the load-bearing wall into a first half-plane and a second half-plane, the first of said second corrugations being located in the first half-plane and the second of said second corrugations being located in the second half-plane, the plurality of membrane portions being interrupted at a polygonal window surrounding the through-element to allow the through-element to pass through, the window interrupting the directors of the two said first undulations and in interrupting the directors of the first of said second undulations and of the second of said second undulations, the sealing membrane comprising at least one closure plate sealingly connecting the plurality of membrane portions to the through-member, the plurality of membrane portions comprising, around the window, a plurality of corrugated metal sheets, the corrugated metal sheets having sides parallel to the first direction and the second direction respectively, the plurality of corrugated metal sheets comprising, in the second half-plane: - a first rectangular metal sheet having a width greater than or equal to 4 times the first wave pitch in the second direction, the first rectangular metal sheet being arranged on the first guideline and symmetrical with respect to the first guideline, the first rectangular metal sheet having a first notched edge facing the through element, - two second singular rectangular metal sheets having a width greater than or equal to 2 times the first wave pitch in the second direction and a length of 1 time the second wave pitch in the first direction, and - two third singular rectangular metal sheets having a width greater than or equal to 3 times the first wave pitch in the second direction and a length of 1 time the second wave pitch in the first direction, and symmetrical to each other with respect to the first guideline, the second singular rectangular metal sheets being arranged on either side of the window and each welded to the first rectangular metal sheet, the third singular rectangular metal sheets being arranged on either side of the first metal sheet and each welded to one of the second singular rectangular metal sheets and to the first rectangular metal sheet, in which the first rectangular metal sheet extends the two said first corrugations to the at least one closing plate, wherein the first rectangular metal sheet, the second singular rectangular metal sheets and the third singular rectangular metal sheets extend other of said first corrugations on either side of the window, wherein the second of said second corrugations is absent from the second singular rectangular metal sheets, and a third of said second corrugations is absent from the third singular rectangular metal sheets.

[0010] Thanks to these characteristics, it is possible to obtain on the sealing membrane two zones adjacent to the through element and devoid of second undulations. An internal element such as an unloading pump can thus be arranged in line with and at a distance from each of these zones in an internal space of the tank. The absence of the second undulations makes it possible to adapt the spacing between the sealing membrane and the unloading pump to optimize the volume of cargo that can be pumped, as described in WO 2023 / 094330 Al.

[0011] Furthermore, due to their dimensions along the first direction, the second singular rectangular metal sheets and the third singular rectangular metal sheets are entirely devoid of the second corrugations. Consequently, either a corrugated metal sheet is provided with the second corrugations spaced apart by the second wave pitch over its entire length along the first direction, or a corrugated metal sheet is entirely devoid of second corrugations. This is advantageous from an economic and industrial point of view, since manufacturing corrugated metal sheets provided with the second corrugations over only a portion of their length along the first direction is difficult and expensive.

[0012] In summary, the sealed and thermally insulating tank makes it possible to adapt the spacing between the sealing membrane and an internal element such as an unloading pump while ensuring that the sealing membrane can be manufactured simply and at a moderate cost.

[0013] According to embodiments, such a sealed and thermally insulating tank may comprise one or more of the following characteristics.

[0014] According to one embodiment, the first wave pitch and the second wave pitch are equal.

[0015] According to one embodiment, the first rectangular metal sheet has a width of NI times the first wave pitch in the second direction, where NI is an integer greater than or equal to 4. Preferably, NI is an even integer, which allows the first rectangular metal sheet both to be arranged symmetrically with respect to the first direction line and to extend first corrugations on either side of the window, without a deviation of these first corrugations in the first half-plane being necessary. More preferably, NI = 4.

[0016] According to one embodiment, the first rectangular metal sheet has a length of Ml times the second wave pitch in the first direction, where Ml is a non-zero integer.

[0017] According to one embodiment, the third singular rectangular metal sheets have a width of N3 times the first wave pitch in the second direction, where N3 is an integer greater than or equal to 3.

[0018] By providing that the sheets have dimensions equal to integer multiples of the first wave pitch and the second wave pitch, the sheets can be manufactured at moderate cost.

[0019] According to one embodiment, the two second singular rectangular metal sheets have a width of between 2 times and 4 times the first wave pitch in the second direction, and N3 = 3.

[0020] Thus, the second singular rectangular metal sheets and the third singular rectangular metal sheets are of small dimensions along the first direction and the second direction, so that they retain sufficient flexibility to thermal contraction / expansion despite the absence of the second corrugations.

[0021] According to one embodiment, the first directrix is equidistant from the directors of the two said first undulations.

[0022] According to one embodiment, the second directrix is equidistant from the directors of the two said second undulations.

[0023] According to one embodiment, an edge of the second singular rectangular metal sheets parallel to the second direction and an edge of the third singular rectangular metal sheets parallel to the second direction delimit a first overlap zone, said first overlap zone being anchored to the thermally insulating barrier over only part of its length.

[0024] According to one embodiment, an internal surface of the thermally insulating barrier forms a support surface for the sealing membrane and carries metal anchoring plates intended to be welded to the membrane portions to retain said plurality of membrane portions against said support surface, and the metal anchoring plates comprise first metal anchoring plates located in the second half-plane in line with the first overlap zone, the first overlap zone being welded to the first metal anchoring plates.

[0025] According to one embodiment, the thermally insulating barrier comprises a plurality of juxtaposed insulating panels each having an internal face which forms the support surface for the sealing membrane, the insulating panels having rectangular parallelepiped shapes whose sides are parallel to the first direction and the second direction of the plane of the load-bearing wall respectively and whose dimensions in projection in the plane of the load-bearing wall are substantially equal to whole multiples of the first wave pitch in the second direction and to whole multiples of the second wave pitch in the first direction.

[0026] The first metal anchoring plates allow the second singular rectangular metal sheets and the third singular rectangular metal sheets to be anchored by welding to the thermally insulating barrier, without risking damage to the insulating panels. The absence of the second corrugations by means of the second singular rectangular metal sheets and the third singular rectangular metal sheets whose length in the first direction is 1 times the second wave pitch does not pose any difficulty with regard to the manufacture of the tank.

[0027] According to one embodiment, the metal anchoring plates comprise second metal anchoring plates located in the second half-plane, an edge of the first rectangular metal sheet parallel to the second direction and opposite the first notched edge of the first rectangular metal sheet along the first direction being welded to the second metal anchoring plates.

[0028] According to one embodiment, the plurality of corrugated metal sheets comprises, in the first half-plane, a notched rectangular metal sheet having a width greater than or equal to 6 times the first wave pitch in the second direction and a length greater than or equal to 3 times the second wave pitch in the first direction, the notched rectangular metal sheet having a notched edge facing the through element, the second singular rectangular metal sheets are each welded to the notched rectangular metal sheet, and the notched rectangular metal sheet extends the two said first corrugations and the first of said second corrugations to the at least one closing plate, and extends the others of said first corrugations on either side of the window.

[0029] According to one embodiment, the notched rectangular metal sheet has a width of N4 times the first wave pitch in the second direction, where N4 is an integer greater than or equal to 6.

[0030] According to one embodiment, the notched rectangular metal sheet has a length of M4 times the second wave pitch in the first direction, where M4 is an integer greater than or equal to 3.

[0031] Preferably, N4 = 6 or 7 and M4 = 3, which makes it possible to manufacture the notched rectangular metal sheet without excessive additional cost.

[0032] According to one embodiment, an edge of the notched rectangular metal sheet parallel to the second direction and an edge of the second singular rectangular metal sheets parallel to the second direction delimit a second overlap zone, the second overlap zone being anchored to the thermally insulating barrier over part of its length.

[0033] According to one embodiment, the metal anchoring plates further comprise third metal anchoring plates arranged on the second guideline, the second overlap zone being welded to the third metal anchoring plates.

[0034] According to one embodiment, the first rectangular metal sheet has a length of 2 times the second wave pitch in the first direction (in other words, Ml = 2) and comprises a corrugation portion extending said third of said second corrugations between the two third rectangular metal sheets sin regular, each third singular rectangular metal sheet being tightly connected to the corrugation portion.

[0035] According to one embodiment, the first rectangular metal sheet is a first singular rectangular metal sheet, said third of said second corrugations being absent from the first singular rectangular metal sheet.

[0036] According to one embodiment, the first singular rectangular metal sheet has a length of 1 times the second wave pitch in the first direction (in other words, Ml = 1) in the first direction.

[0037] According to one embodiment, the second singular rectangular metal sheets each comprise a second notched edge facing the through element and extending the first notched edge of the first rectangular metal sheet.

[0038] According to one embodiment, the first singular rectangular metal sheet has a length of 2 times the second wave pitch in the first direction (in other words, Ml = 2) in the first direction and is welded to each of the second singular rectangular metal sheets at a distance from the window.

[0039] According to one embodiment, the first corrugations have a height in the thickness direction of the tank wall less than a height in the thickness direction of the tank wall of the second corrugations.

[0040] According to one embodiment, the sealing membrane comprises a first closure plate in the first half-plane and a second closure plate in the second half-plane, the first closure plate and the second closure plate surrounding the through-member. According to one embodiment in this case, the first notched edge of the first rectangular metal sheet is sealed welded to the second closure plate, and the second notched edge of the notched rectangular metal sheet is sealed welded to the first closure plate. The notched rectangular metal sheet may extend the two said first corrugations and the first of the two said second corrugations to first end pieces sealedly connected to the first closure plate.The first rectangular metal sheet may extend the two said first corrugations to second end pieces connected in a sealed manner to the second closing plate.

[0041] According to one embodiment, the tank comprises an internal space delimited by the sealing membrane, the tank comprising an internal element located in the internal space of the tank, the internal element being located in line with and at a distance in the thickness direction of the tank wall from a said second singular rectangular metal sheet and from a said third singular rectangular metal sheet adjacent to said second metal sheet. singular rectangular metal sheet.

[0042] According to one embodiment, the tank comprises a loading / unloading tower and an unloading pump fixed to the loading / unloading tower, the through element being a support foot for the loading / unloading tower that the tank comprises.

[0043] According to one embodiment, the loading / unloading tower comprises a plurality of masts connected at a lower end to each other using a base, the base comprising a guide device cooperating with the support foot, the support foot being configured to ensure vertical translational guidance of the loading / unloading tower.

[0044] According to one embodiment, the internal element located at right angles to and at a distance in the thickness direction from the tank wall of a said second singular rectangular metal sheet and of a said third singular rectangular metal sheet adjacent to said second singular rectangular metal sheet is formed by the unloading pump.

[0045] As mentioned above, the absence of the second corrugations on the second singular rectangular metal sheets and the third singular rectangular metal sheets allows the spacing between the sealing membrane and the unloading pump to be adapted to optimize the volume of cargo that can be pumped.

[0046] According to one embodiment, the internal element is connected to the support foot.

[0047] In one embodiment, the liquefied gas is LNG, namely a high- methane content stored at a temperature of approximately -162°C at atmospheric pressure. Other liquefied gases may also be considered, including ethane, propane, butane, or ethylene. Liquefied gases may also be stored under pressure, for example at a relative pressure of between 2 and 20 bar, and in particular at a relative pressure of around 2 bar. The tank may be constructed using various techniques, including an integrated membrane tank or a self-supporting tank.

[0048] Such a tank may be part of a land-based storage facility, for example for storing LNG, or may be installed in a floating, coastal, or deep-water structure, including an LNG carrier, a floating storage and regasification unit (FSRU), a floating production and remote storage unit (FPSO), and others. Such a tank may also serve as a fuel tank in any type of vessel.

[0049] According to one embodiment, a ship for transporting a liquefied gas comprises a double hull and a aforementioned tank arranged in the double hull.

[0050] According to one embodiment, the invention also provides a transfer system for a liquefied gas, the system comprising the aforementioned vessel, insulated pipes arranged to connect the vessel's tank to a floating or land-based storage facility and a pump for driving a flow of liquefied gas through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

[0051] According to one embodiment, the invention also provides a method for loading or unloading such a ship, in which a liquefied gas is conveyed through insulated pipes from or to a floating or land-based storage facility to or from the tank of the ship. Brief description of the figures

[0052] The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes, with reference to the appended drawings.

[0053] [Fig-1] [Fig. 1] is a partial schematic cross-sectional representation of a tank waterproof and thermally insulating in the area of a support foot.

[0054] [Fig.2] [Fig.2] is a view of detail II of [Fig.l].

[0055] [Fig.3] [Fig.3] is a partial top view of a back wall at a support foot and according to a first embodiment.

[0056] [Fig.4] [Fig.4] is a partial top view of a thermally insulating material placed under the waterproofing membrane visible in [Fig.3].

[0057] [Fig.5] [Fig.5] is a partial top view of a back wall at a support foot and according to a second embodiment.

[0058] [Fig.6] [Fig.6] is a partial top view of a thermally insulated barrier insulating material placed under the waterproofing membrane visible in [Fig.5].

[0059] [Fig.7] [Fig.7] is a partial top view of a back wall at a support foot and according to a third embodiment.

[0060] [Fig.8] [Fig.8] is a partial top view of a thermally insulated barrier insulating material placed under the waterproofing membrane visible in [Fig.7].

[0061] [Fig.9] [Fig.9] is a schematic cutaway representation of a ship's tank LNG tanker and a loading / unloading terminal for this tank. Description of the embodiments

[0062] In [Fig.l], a sealed and thermally insulating tank 71 intended for the storage and / or transport of liquefied gas is partially seen, consisting of a bottom wall 1 fixed to the inner surface of a supporting structure 2. The supporting structure 2 is, for example, the inner hull of a double-hulled ship or a construction located on land. To contain a cold liquid such as LNG, the tank walls comprise at least at least one sealing membrane 4 and at least one thermally insulating barrier 3 located between the sealing membrane 4 and the supporting structure 2. As a safety measure, it is possible to provide a secondary sealing membrane and a secondary thermally insulating barrier, not shown, between the supporting structure and the thermally insulating barrier 3, which is called primary in this case.

[0063] The liquefied gas intended to be stored in the tank 71 may in particular be a liquefied natural gas (LNG), that is to say a gas mixture comprising mainly methane and one or more other hydrocarbons. The liquefied gas may also be ethane or a liquefied petroleum gas (LPG), that is to say a mixture of hydrocarbons resulting from the refining of petroleum comprising essentially propane and butane.

[0064] The tank 71 can be made according to various well-known geometries, for example a prismatic geometry in the hull of a ship or a cylindrical geometry on land or the like. Furthermore, numerous methods are available for making the thermally insulating barriers and the sealing membranes, for example from prefabricated elements.

[0065] In the bottom wall 1 of the tank, an elongated rigid element is shown, constituting a support foot 5, which extends through the thermally insulating barrier 3 and the sealing membrane 4, so that a part of the support foot 5 bears against the supporting structure 2 and another part projects into the tank at a distance from the sealing membrane 4. The support foot 5 can for example be used to support equipment 7 to be immersed in the tank. For example, to support an unloading pump 7, a loading / unloading tower 6 can be arranged in the tank as shown schematically in [Fig.l]. Instead of a loading / unloading tower 6, the tank 71 can have loading and unloading pipes which are not connected to each other and guided by means of the support foot 5.

[0066] In the case of a loading / unloading tower 6, the latter comprises a structure formed of several masts connected at a lower end to each other by means of a base. The loading / unloading tower 6 further comprises a guide device which is fixed against the lower face of the base and which cooperates with the support foot 5.

[0067] The support foot 5 is configured to provide vertical translational guidance of the loading / unloading tower 6 (or only of the loading and unloading pipes), the unloading pump 7 being fixed to the loading / unloading tower 6 or directly to the support foot 5.

[0068] The support foot 5 here has a shape of revolution with a circular section, with a truncated lower part 8 which connects at its end to more small diameter to a cylindrical upper part 9. The larger diameter base of the truncated conical part 8 bears against the supporting structure 2. The truncated conical part 8 extends through the thickness of the bottom wall 1 beyond the level of the waterproofing membrane 4.

[0069] In a manner not shown in [Fig. 1] and [Fig. 2], the thermally insulating barrier 3 comprises a plurality of rectangular parallelepiped insulating blocks juxtaposed with each other. These insulating blocks will be described in more detail below.

[0070] With reference to [Fig.2] and [Fig.3], the sealing membrane 4 comprises a plurality 10 of corrugated metal sheets. The corrugated metal sheets have an internal face intended to be in contact with the fluid contained in the tank. The corrugated metal sheets may be made in particular of stainless steel or of an iron and nickel alloy called Invar® and are welded together at overlapping zones. The welds are of the overlap weld type. The corrugated metal sheets may be designed in various ways as to their shapes and dimensions, so that the weld zones may be variously positioned. Some of the corrugated metal sheets (hereinafter referred to as “the sheets” for convenience) are shown in [Fig.3] and will be described in more detail below.

[0071] Regular sheets 68, 69 comprise, on their internal face, a series of first corrugations 11 and a series of second corrugations 12 (see [Fig.2], [Fig.3]). With reference to [Fig.3], the first corrugations 11 are parallel to each other and extend in a first direction DI and the second corrugations 12 are parallel to each other and extend in a second direction D2. The second direction D2 is orthogonal to the direction DI.

[0072] The first corrugations 11 have a height greater than the second corrugations 12. The height of a corrugation is measured between the crest of the corrugation and the level of the flat portion 19. With reference to [Fig. 2], the sealing membrane 4 further comprises corrugation nodes 15 formed at the intersection between a first corrugation 11 and a second corrugation 12. Each corrugation node 15 has a height greater than the height of the second corrugations 12. The corrugation nodes 15 are not shown in Figures 3, 5, 7 so as not to overload the drawing. The corrugations 11, 12 project towards the inside of the tank 71.

[0073] Still referring to [Fig. 3], the first undulations 11 are spaced apart by a first wave pitch PI in the second direction D2, and the second undulations 12 are spaced apart by a second wave pitch P2 in the first direction DI. The first wave pitch PI and the second wave pitch P2 are measured between the crests of two adjacent undulations. The first wave pitch PI and the second wave pitch P2 may be identical as shown, or be different. The sheets of the plurality 10 comprise flat portions 19 located between the first corrugations 11 and between the second corrugations 12 so that the flat portions 19 rest against the thermally insulating barrier 3.

[0074] A first embodiment will now be described with reference to Figures 1 to 4.

[0075] [Fig. 3] is a partial top view of the bottom wall 1 from the inside of the tank 71, in other words from the internal space of the tank delimited by the sealing membrane 4 and in which the fluid is contained. In [Fig. 3], the support foot 5 and some of the sheets arranged around or in the vicinity of the support foot 5 are shown.

[0076] The support foot 5 is centered on the intersection X between a first guideline Al (represented in dotted lines in [Fig.3]) and a second guideline A2 (represented in dotted lines and in solid lines in [Fig.3]). The first guideline A1 extends in the first direction D1 and is equidistant from two adjacent first corrugations 13 among the first corrugations 11. The second guideline A2 extends in the second direction D2 and is equidistant from two adjacent first corrugations 14, 16 among the second corrugations 12. Alternatively, the first guideline A1 may extend between the corrugations 13 and not be equidistant from the corrugations 13, and / or the second guideline A2 may extend between the corrugations 14, 16 and not be equidistant from the corrugations 14, 16.

[0077] The second guideline A2 divides the plane of the load-bearing wall into a first half-plane PA, at the top of the drawing in [Fig.3], and a second half-plane PF, at the bottom of the drawing in [Fig.3]. The corrugation 14 is located in the half-plane PA, and the corrugation 16 is in the half-plane PF.

[0078] The plurality 10 of corrugated metal sheets is interrupted at a polygonal window 24 (hereinafter referred to as "the window 24" for convenience). The window 24 surrounds the through-member 5 to allow the through-member 5 to pass through. In the example shown, the window 24 has the shape of a regular octagon centered on the intersection X. Alternatively, other polygonal shapes are conceivable for the window 24, in particular a square, a rectangle, etc.

[0079] The window 24 interrupts the G directors of the two undulations 13 in the DI direction and interrupts the H directors of the two undulations 14, 16 in the D2 direction. The G and H directors are partially represented in dot-and-dash lines in [Fig.3].

[0080] To extend the sealing membrane 4 and thus ensure the sealing of the tank around the support foot 5, two closing plates 25, 26 are arranged in the window 24. The closing plates 25, 26 connect the plurality 10 of corrugated metal sheets to the support foot 5 in a sealed manner. The closing plate 25 is located in the half-plane PA and the closing plate 26 is located in the half-plane PF. The closure plates 25, 26 may for example be symmetrical with respect to the second guideline A2 as shown. In the half-plane PA, the corrugations 13 and the corrugation 14 are connected in a sealed manner to the closure plate 25 by end pieces 27. In the half-plane PF, the corrugations 13 are connected in a sealed manner to the closure plate 26 by end pieces 28. On the other hand, the corrugation 16 is not connected to the closure plate 26 as will be detailed below. The support foot 5, the closure plates 25, 26, and the end pieces 27, 28 may in particular be produced according to the teaching of the document WO 2011 / 157915 A1 or WO 2016 / 170254 A1 Alternatively, other constructions are possible. In particular, a different number of closure plates may be provided and / or the closure plates may have different geometries.

[0081] The sheets shown in [Fig. 3] have rectangular shapes whose sides are parallel to, respectively, the first direction DI and the second direction D2. The dimensions of the sides of the sheets in the first direction DI and the second direction D2 are substantially equal to, respectively, integer multiples of the second wave pitch P2 and the first wave pitch PL. It should be noted that some of the sheets have been omitted in [Fig. 3], in particular sheets located far from the window 24.

[0082] We now describe the sheets shown in [Fig.3] which are located in the half-plane PF.

[0083] A sheet 41 is arranged on the first guideline A1 and symmetrical with respect to the first guideline A1. The sheet 41 has a notched edge 42 facing the support foot 5. The notched edge 42 is welded in a sealed manner to the closing plate 26.

[0084] In the example shown, the sheet 41 has a width of 4 times the first wave pitch PI in the second direction D2. Alternatively, the sheet 41 has a width greater than 4 times PI in the second direction D2, preferably a width of NI times PI where NI is an integer greater than 4. More preferably, NI is even.

[0085] Two singular sheets 51 having a length of 1 times the second wave pitch P2 in the first direction DI are arranged on either side of the first direction line AL. Each singular sheet 51 has a notched edge 52 facing the support foot 5 and extending the notched edge 42 to the sheet 31 described below in the half-plane PA. The notched edges 52 are welded in a sealed manner to the closing plate 26. On each side of the window 24, the singular sheet 51 and the sheet 41 are welded at their overlapping zones 54 parallel to the second direction D2.

[0086] In the example shown, the singular sheets 51 have a width of between 3 times and 4 times the first wave pitch PI in the second direction D2. More particularly, one of the singular sheets 51 (on the right in [Fig.3]) has a width of 4 times PI and the other of the singular sheets 51 (on the left in [Fig.3]) has a smaller width, strictly less than 4 times PI. Alternatively, the singular sheets 51 could be symmetrical to each other with respect to the first guideline Al.

[0087] Two singular sheets 61 having a length of 1 times the second wave pitch P2 in the first direction DI are arranged on either side of the sheet 41. More precisely, the singular sheets 61 are symmetrical to each other with respect to the first direction line A1. On each side of the window 24, the singular sheet 61 and the sheet 41 are welded at their overlapping zones 64 parallel to the first direction D1, the singular sheet 61 and the singular sheet 51 are welded at their overlapping zones 65 parallel to the second direction D2, and the singular sheet 61 and an adjacent regular sheet 69 are welded at their overlapping zones 66 parallel to the second direction D2.

[0088] In the example shown, the singular sheets 61 have a width of 3 times the first wave pitch PI in the second direction D2. Alternatively, the singular sheets 61 have a width greater than 3 times PI in the second direction D2, preferably a width of N3 times P2 where N3 is an integer.

[0089] As can be seen in [Fig. 3], the sheet 41 extends the corrugations 13 to the closing plate 26, the corrugations 13 being connected in a sealed manner to the closing plate 26 by end pieces 28 as mentioned above. In addition, the sheet 41 and the singular sheets 51, 61 extend other corrugations 11 on either side of the window 24.

[0090] On the other hand, the corrugation 16 is absent from the sheets 51, so that the corrugation 16 is not extended to the closing plate 26. In addition, the corrugation 18 of the series of second corrugations 12 closest to the corrugation 16 in the half-plane PF is absent from the sheets 61. It is thus possible to obtain on the sealing membrane 4 two zones close to the support foot 5 and devoid of the second corrugations 12. An unloading pump 7 (shown in dotted lines in [Fig. 3]) can thus be arranged in line with and at a distance from each of these zones in the internal space of the tank 71. With reference to [Fig.2], the absence of the second corrugations 12 on the sheets 51, 61 makes it possible to ensure that the minimum spacing 22 under the unloading pump 7 is increased by a spacing gain 23, which makes it possible to adapt the spacing between the sealing membrane 4 and the unloading pump 7 to optimize the volume of cargo that can be pumped, as described in document WO 2023 / 094330 Al.

[0091] The corrugations 16, 18 can be sealed by end pieces 48 similar to the end pieces 27, 28 which are welded at the level of the overlap zone between the sheets 51, 61 and an adjacent regular sheet 69.

[0092] The sheet 41 here has a corrugation portion 18U extending the corrugation 18 between the singular sheets 61. The corrugation portion 18U is closed in a sealed manner by end pieces 49 similar to the end pieces 27, 28, 48 at the level of each overlap zone between the sheet 41 and a singular sheet 61.

[0093] Finally, the sheet 41 having a length of 2 times the second wave pitch P2 in the first direction D1, the sheet 41 extends a second corrugation 12 on the side opposite the window 24.

[0094] Regular sheets 69 are arranged around the sheets 41, 51, 61 in the half-plane PF and are welded to the sheets 41 and / or 51 and / or 61. The regular sheets 69 can be sized in a large number of ways according to requirements. The dimensions of the regular sheets 69 shown in [Fig.3] are therefore only an example.

[0095] We now describe the sheets shown in [Fig.3] which are located in the half-plane PA.

[0096] A notched sheet 31 has a notched edge 32 facing the support foot 5. The notched edge 32 is welded in a sealed manner to the closing plate 25. On each side of the window 24, the singular sheet 51 and the notched sheet 31 are welded at their overlapping zones 53 parallel to the second direction D2 and located on the second guideline A2.

[0097] The notched sheet 31 here has a width of 7 times the first wave pitch PI in the second direction D2 and a length of 3 times the second wave pitch P2 in the first direction D1, which makes it possible to manufacture the notched sheet 31 without excessive additional cost. As a variant, the notched sheet 31 has a width greater than or equal to 6 times PI in the second direction D2, preferably a width of N4 times PI where N4 is an integer, and / or a length greater than 3 times P2 in the first direction D1, preferably a length of M4 times P2 where M4 is an integer.

[0098] As can be seen in [Fig.3], the notched sheet 31 extends the corrugations 13 to the closing plate 25, in a similar manner to the sheet 4L. Furthermore, the notched sheet 31 extends other corrugations 11 on either side of the window 24, to the singular sheets 51. Finally, the notched sheet 31 extends the corrugation 14 to the closing plate 25.

[0099] Regular sheets 68 are arranged around the notched sheet 31 in the half-plane PF and are welded to the notched sheet 31. A single regular sheet 68 is shown in [Fig. 3] for the sake of simplicity. The regular sheets 68 can be sized in a large number of ways as required. The dimensions of the regular sheet 68 shown in [Fig. 3] are therefore only an example.

[0100] Finally, it is specified that the sheets constituting the sealing membrane 4 which are not shown in [Fig.3] can also be sized in a large number of ways according to requirements.

[0101] As mentioned above, the thermally insulating barrier 3 comprises a plurality of rectangular parallelepiped insulating blocks juxtaposed with each other. In [Fig. 4], which is a view of the thermally insulating barrier 3 arranged below the sealing membrane 4 shown in [Fig. 3], three of said insulating blocks 80 are shown together with the support foot 5. The insulating blocks 80 comprise a cover panel facing towards the inside of the tank, an upper face of the cover panel carrying a metal anchoring plate. Bridging elements 81 are arranged in gaps between the insulating blocks 80 and also comprise a cover panel facing towards the inside of the tank, an upper face of the cover panel being able to carry a metal anchoring plate. Such insulating blocks 80 and bridging elements 81 are for example described in document US6035795.The upper faces of the cover panels together form a support surface for the waterproofing membrane 4. The metal anchor plates are, for example, riveted to the upper faces of the cover panels.

[0102] It can also be seen in [Fig.4] that the support foot 5 is surrounded by corner blocks and anchoring plates produced according to the teaching of document WO 2011 / 157915 A1 or document WO 2016 / 170254 A1

[0103] The references 91 in [Fig. 4] designate thermal protections (symbolized by hatched areas), i.e. strips of glass wool or other thermal insulation. The thermal protections 91 are arranged on the cover panels under edges of the corrugated metal sheets or under the end pieces 27, 28, 48, 49, which makes it possible to weld these edges of the corrugated metal sheets and these end pieces 27, 28, 48, 49 without anchoring them to the insulating blocks 80 and without burning the cover panels of the insulating blocks 80. The reference 800 in [Fig. 4] designates similar thermal protections around the support foot 5.

[0104] Still with reference to [Fig.4], the aforementioned metal anchoring plates comprise anchoring plates 95, 96, 97.

[0105] With reference to [Fig.3] and [Fig.4], the anchoring plates 96 are located in the half-plane PF and extend in the second direction D2, and the overlap zones 65 (see [Fig.3]) are welded to the anchoring plates 96 (see [Fig.4]). Thus, the singular sheets 51, 61 are not only welded to each other at the overlap zone 65, but also anchored by welding to the anchoring plates 96 carried by the thermally insulating barrier 3. Thus, the absence of the corrugations 12 on the singular sheets 51, 61 does not pose any difficulty with regard to the manufacture of the tank.

[0106] The anchoring plates 95 are located on the second guideline A2 and extend in the second direction D2. The overlap zones 53 (see [Fig.3]) are welded to the anchor plates 95 (see [Fig.4]). Thus, the singular sheets 51 are not only welded to the sheet 31, but also anchored to the thermally insulating barrier 3.

[0107] The anchoring plates 97 are located in the half-plane PF and extend in the second direction D2. With reference to [Fig.3] and [Fig.4], the edge 43 (see [Fig.3]) of the sheet 41 parallel to the second direction D2 and opposite the notched edge 42 is welded to the anchoring plates 97 (see [Fig.4]). Thus, the sheet 41 is not only welded to an adjacent regular sheet 69, but also anchored to the thermally insulating barrier 3. Alternatively, the edge 43 may not be anchored to the thermally insulating barrier 3. In this case, the anchoring plates 97 are replaced by thermal protections 91 to protect the thermally insulating barrier 3 when welding the edge 43 to the adjacent regular sheet 69.

[0108] A second embodiment is now described with reference to Figures 5 and 6. In these figures, elements similar or identical to those described with reference to Figures 1 to 4 bear the same reference signs and are not described again.

[0109] With reference to [Fig.5], in the second embodiment, the sheet 41 of the first embodiment is replaced by a sheet 141 with a length of 1 times PI in the second direction D2. The corrugations 12 and 18 are absent from the sheet 141, and the sheet 141 is furthermore devoid of the corrugation portion 18U extending the corrugation 18.

[0110] Like the edge 43 in the first embodiment, the edge 143 (see [Fig.5]) of the sheet 141 parallel to the second direction D2 and opposite the notched edge 42 can be welded to anchoring plates 197 (see [Fig.6]). Alternatively, the edge 143 may not be anchored to the thermally insulating barrier 3. In this case, the anchoring plates 197 are replaced by thermal protections 91.

[0111] The second embodiment is otherwise identical to the first embodiment and is therefore not described further for the sake of brevity.

[0112] A third embodiment is now described with reference to Figures 7 and 8. In these figures, elements similar or identical to those described with reference to Figures 1 to 4 bear the same reference signs and are not described again.

[0113] With reference to [Fig.7], in the third embodiment, the sheet 141 of the second embodiment is replaced by a sheet 241 with a length of 2 times PI in the first direction DI. The corrugations 12 and 18 are absent from the sheet 241, and the sheet 241 is furthermore devoid of the corrugation portion 18U extending the corrugation 18.

[0114] Furthermore, the singular sheets 51 are replaced by singular sheets 251 with a width of between 2 times and 3 times PI in the second direction D2. More particularly, one of the singular sheets 251 (on the right in [Fig.3]) has a width of 3 times PI and the other of the singular sheets 251 (on the left in [Fig.3]) has a smaller width, strictly less than 3 times PI. Alternatively, the singular sheets 251 could be symmetrical to each other with respect to the first direction line A1. On each side of the window 24, the singular sheet 251 and the sheet 241 are welded at their overlapping zones 256 parallel to the first direction D1, the singular sheet 251 and the sheet 31 are welded at their overlapping zones 253 facing parallel to the second direction D2 and located on the second direction line A2, and the singular sheet 251 and the singular sheet 61 are welded at their overlapping zones 265 parallel to the second direction D2.

[0115] The sheet 241 has a notched edge 242 similar to the notched edge 42 and extending to the sheet 31. On each side of the window 24, the sheet 241 and the sheet 31 are welded at their overlapping zones 255 parallel to the second direction D2 and located on the second guideline A2.

[0116] Thanks to this geometry of the sheet 241, one of the singular sheets 251 has the same dimensions as the singular sheets 61, or possibly the two singular sheets 251 if these are symmetrical to each other with respect to the first directrix A1.

[0117] Referring now to [Fig.7] and [Fig.8], the overlapping areas 265 are welded to the anchoring plates 96. Similarly, the overlapping areas 253 are welded to the anchoring plates 95.

[0118] Like the edge 143 in the second embodiment, the edge 243 (see [Fig.7]) of the sheet 241 parallel to the second direction D2 and opposite the notched edge 242 can be welded to the anchoring plates 197 (see [Fig.8]). Alternatively, the edge 243 may not be anchored to the thermally insulating barrier 3. In this case, the anchoring plates 197 are replaced by thermal protections 91.

[0119] The third embodiment is otherwise identical to the second embodiment and is therefore not described further for the sake of brevity.

[0120] The invention has been described in connection with an unloading pump 7. However, it obviously applies to any element internal to the tank 71 located near the sealing membrane 4.

[0121] With reference to [Fig.9], a cutaway view of an LNG carrier ship 70 shows a sealed and thermally insulating tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary sealing membrane intended to be in contact with the LNG contained in the tank, a secondary sealing membrane arranged between the primary sealing membrane and the double hull 72 of the ship, and two thermally insulating barriers arranged respectively between the primary sealing membrane and the sealing membrane secondary and between the secondary waterproofing membrane and the double shell 72.

[0122] In a manner known per se, loading / unloading pipes 73 arranged on the upper deck of the ship can be connected, by means of appropriate connectors, to a maritime or port terminal to transfer a cargo of LNG from or to the tank 71.

[0123] [Fig.9] represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an onshore installation 77. The loading and unloading station 75 is a fixed offshore installation comprising a mobile arm 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipelines 73. The orientable mobile arm 74 adapts to all sizes of LNG carriers. A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore installation 77. The latter comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 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 installation 77 over a long distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a great distance from the coast during loading and unloading operations.

[0124] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the onshore installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0125] Although the invention has been described in connection with several particular embodiments, it is quite obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0126] The use of the verb “comprise”, “comprise” or “include” and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim.

[0127] In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims

Claims

1. A sealed and thermally insulating tank (71) integrated in a supporting structure (2) comprising a supporting wall, said tank comprising a tank wall (1) fixed to the supporting wall of the supporting structure (2), wherein the tank wall (1) comprises, in a thickness direction from the outside to the inside of the tank, a thermally insulating barrier (3) and a sealing membrane (4) supported by the thermally insulating barrier (3) and intended to be in contact with a fluid contained in the tank, the sealing membrane (4) comprising a plurality of membrane portions juxtaposed and welded to each other, the plurality of membrane portions comprising at least one regular membrane portion (68, 69), the regular membrane portion (68, 69) having a series of first parallel undulations (11) extending in a first direction (D1) and spaced apart by a first wave pitch (PI) in a second direction (D2),the second direction (D2) being orthogonal to the first direction (D1), and a series of second parallel corrugations (12) extending in the second direction (D2) and spaced apart by a second corrugation pitch (P2) in the first direction (D1), the tank (71) comprising a through element (5) passing through the tank wall (1), the through element (5) being centered on the intersection (X) between a first guideline (A1) extending in the first direction (D1) and located between the directors of two (13) of said first corrugations (11) and a second guideline (A2) extending in the second direction (D2) and located between a first (14) and a second (16) of said second corrugations (12), the second guideline (A2) dividing the plane of the load-bearing wall into a first half-plane (PA) and a second half-plane (PF),the first (14) of said second undulations being located in the first half-plane (PA) and the second (16) of said second undulations being located in the second half-plane (PF), the plurality of membrane portions being interrupted at a polygonal window (24) surrounding the through-element (5) to allow the through-element (5) to pass, the window (24) interrupting the directors (G) of the two said first undulations (13) and interrupting, the directors (H) of the first (14) of said second undulations and of the second (16) of said second undulations, the sealing membrane (4) comprising at least one closure plate (25, 26) sealingly connecting the plurality of membrane portions to the through-element (5), the plurality of membrane portions comprising, around the window (24), a plurality of corrugated metal sheets, the corrugated metal sheets having sides parallel to the first direction (D1) and the second direction (D2) respectively, the plurality of corrugated metal sheets comprising, in the second half-plane (PF): - a first rectangular metal sheet (41, 141, 241) having a width greater than or equal to 4 times the first wave pitch (PI) in the second direction (D2), the first rectangular metal sheet (41, 141, 241) being arranged on the first guideline (A1) and symmetrical with respect to the first guideline (A1), the first rectangular metal sheet (41, 141, 241) having a first notched edge (42, 242) facing the through-element (5), - two second singular rectangular metal sheets (51, 251) having a width greater than or equal to 2 times the first wave pitch (PI) in the second direction (D2) and a length of 1 time the second wave pitch (P2) in the first direction (Dl), and - two third singular rectangular metal sheets (61) having a width greater than or equal to 3 times the first wave pitch (PI) in the second direction (D2) and a length of 1 time the second wave pitch (P2) in the first direction (Dl), and symmetrical to each other with respect to the first guideline (A1), the second singular rectangular metal sheets (51, 251) being arranged on either side of the window (24) and each welded to the first rectangular metal sheet (41, 141, 241), the third singular rectangular metal sheets (6 ... other of the first metal sheet (41, 141,241) and each welded to one of the second singular rectangular metal sheets (51, 251) and to the first rectangular metal sheet (41, 141, 241), in which the first rectangular metal sheet (41, 141, 241) extends the two said first corrugations (13) up to the at least one closing plate (25, 26), in which the first rectangular metal sheet (41, 141, 241), the second singular rectangular metal sheets (51, 251) and the third singular rectangular metal sheets (61) extend other of said first corrugations (11) on either side of the window (24), in which the second (16) of said second corrugations is absent from the second singular rectangular metal sheets (51), and a third (18) of said second corrugations is absent from the third singular rectangular metal sheets (61).

2. A sealed and thermally insulating tank (71) according to claim 1, wherein an edge of the second singular rectangular metal sheets (51, 251) parallel to the second direction (D2) and an edge of the third singular rectangular metal sheets (61) parallel to the second direction (D2) delimit a first overlap zone (65, 265), said first overlap zone (65, 265) being anchored to the thermally insulating barrier (3) over only part of its length.

3. A sealed and thermally insulating tank (71) according to claim 2, wherein an internal surface of the thermally insulating barrier (3) forms a support surface for the sealing membrane and carries metal anchoring plates intended to be welded to the membrane portions to retain said plurality of membrane portions against said support surface, wherein the metal anchoring plates comprise first metal anchoring plates (96) located in the second half-plane (PF) at right angles to the first overlap zone (65, 265), the first overlap zone (65, 265) being welded to the first metal anchoring plates (96).

4. A sealed and thermally insulating tank (71) according to claim 3, wherein the metal anchoring plates comprise second metal anchoring plates (97, 197) located in the second half-plane (PF), an edge (43, 143, 243) of the first rectangular metal sheet (41, 141, 241) parallel to the second direction (D2) and opposite the first notched edge (42, 242) of the first rectangular metal sheet (41, 141, 241) along the first direction (D2) being welded to the second metal anchoring plates (97, 197).

5. A sealed and thermally insulating tank (71) according to any one of claims 1 to 4, wherein the plurality of corrugated metal sheets comprises, in the first half-plane (PA), a metal sheet- notched rectangular metal sheet (31) having a width greater than or equal to 6 times the first wave pitch (PI) in the second direction (D2) and a length greater than or equal to 3 times the second wave pitch (P2) in the first direction (Dl), the notched rectangular metal sheet (31) having a notched edge (32) facing the through element (5), in which the second singular rectangular metal sheets (51, 251) are each welded to the notched rectangular metal sheet (31), and in which the notched rectangular metal sheet (31) extends the two said first corrugations (13) and the first (14) of said second corrugations to the at least one closing plate (25, 26), and extends the others of said first corrugations (11) on either side of the window (24).

6. A sealed and thermally insulating tank (71) according to claim 5, wherein an edge of the notched rectangular metal sheet (31) parallel to the second direction (D2) and an edge of the second singular rectangular metal sheets (51, 251) parallel to the second direction (D2) delimit a second overlap zone (53, 253), the second overlap zone (53, 253) being anchored to the thermally insulating barrier (3) over only part of its length.

7. A sealed and thermally insulating tank (71) according to claim 6 taken in combination with claim 3 or claim 4, wherein the metal anchor plates further comprise third metal anchor plates (95) arranged on the second guideline (A2), the second overlap zone (53, 253) being welded to the third metal anchor plates (95).

8. A sealed and thermally insulating tank (71) according to any one of claims 1 to 7, wherein the first rectangular metal sheet (41) has a length of 2 times the second wave pitch (P2) in the first direction (D1) and comprises a corrugation portion (18U) extending said third (18) of said second corrugations between the two third singular rectangular metal sheets (61), each third singular rectangular metal sheet (61) being connected in a sealed manner to the corrugation portion (18U).

9. A sealed and thermally insulating tank (71) according to any one of claims 1 to 7, wherein the first metal sheet rec- tangular is a first singular rectangular metal sheet (141, 241), said third (18) of said second corrugations being absent from the first singular rectangular metal sheet (141, 241).

10. A sealed and thermally insulating tank (71) according to claim 9, wherein the first singular rectangular metal sheet (141) has a length of 1 times the second wave pitch (P2) in the first direction (D1).

11. A sealed and thermally insulating tank according to any one of claims 8 to 10, in which the second singular rectangular metal sheets (51) each comprise a second notched edge (52) facing the through element (5) and extending the first notched edge (42) of the first singular rectangular metal sheet (41, 141).

12. A sealed and thermally insulating tank (71) according to claim 9, wherein the first singular rectangular metal sheet (241) has a length of 2 times the second wave pitch (P2) in the first direction (D1) and is welded to each of the second singular rectangular metal sheets (251) at a distance from the window (24).

13. A sealed and thermally insulating tank (71) according to any one of claims 1 to 12, wherein the first corrugations (11) have a height in the thickness direction of the tank wall (1) less than a height in the thickness direction of the tank wall (1) of the second corrugations (12).

14. A sealed and thermally insulating tank (71) according to any one of claims 1 to 13, wherein the sealing membrane (4) comprises a first closure plate (25) in the first half-plane (PA) and a second closure plate (26) in the second half-plane (PF), the first closure plate (25) and the second closure plate (26) surrounding the through-element (5).

15. A sealed and thermally insulating tank (71) according to any one of claims 1 to 14, wherein the tank (71) comprises a loading / unloading tower (6) and an unloading pump (7) fixed to the loading / unloading tower (6), the through member (5) being a support foot for the loading / unloading tower (6).

16. A vessel (70) for transporting a liquefied gas, the vessel comprising a double hull (72) and a tank (71) according to any one of claims 1 to 15 disposed in the double hull.

17. A transfer system for a liquefied gas, the system comprising a A vessel (70) according to claim 16, insulated pipes (73, 79, 76, 81) arranged to connect the vessel tank (71) to a floating or land-based storage facility (77) and a pump for driving a flow of liquefied gas through the insulated pipes from or to the floating or land-based storage facility to or from the vessel tank.

18. A method of loading or unloading a vessel (70) according to claim 16, wherein a liquefied gas is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or land-based storage facility (77) to or from the tank (71) of the vessel (70).

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