JP7497137B2 - Sealed and insulated tank - Google Patents

Description

The present invention relates to the field of sealed insulated tanks. In particular, the present invention relates to the field of sealed insulated tanks for the storage or transportation of cryogenic liquids, such as tanks for ships carrying liquefied petroleum gas (also called LPG) at temperatures between -50°C and 0°C, or tanks for carrying liquefied natural gas (LNG) at approximately -162°C at atmospheric pressure.

Sealed, insulated tanks for ships are known, for example, from WO 2017064413 A1. That document describes a tank for a propane or methane tanker comprising a number of tank walls. Each wall of the tank comprises at least one sealing membrane and one insulating barrier.

JP2009079736 proposes an on-land tank for cryogenic liquids with a support structure made of concrete and an insulating barrier including an M-shaped element, which is designed to match the thickness of the insulating barrier by changing the height of the M-shaped element. However, the M-shaped element requires complex molding.

International Publication No. 2017064413 JP 2009079736 A

One object of the present invention is to propose a corner structure capable of supporting one or more sealing membranes at the corner between two walls of a tank and capable of adapting to various thicknesses of the insulating barrier.

The present invention provides a sealed insulated tank for storing a fluid, comprising a first wall and a second wall, each of which comprises, in a thickness direction, a support wall, an insulating barrier fixed to the support wall, and a sealing membrane parallel to the support wall and fixed to the insulating barrier, the sealed insulated tank comprising a corner structure at an edge corner between the support wall of the first wall and the support wall of the second wall, the corner structure comprising a first fixing flange fixed to the support wall of the second wall, a second fixing flange fixed to the support wall of the first wall, and a sealing corner member fixed to the first fixing flange via a first connecting member on the one hand and to the second fixing flange via a second connecting member on the other hand. The sealing corner member is sealingly connected to the sealing membrane of the first wall and the sealing membrane of the second wall, the sealing corner member comprising a first flat branch extending in the plane of the sealing membrane of the second wall and a second flat branch extending in the plane of the sealing membrane of the first wall, the first connecting member comprising a first flat branch parallel to the first fixing flange and a second flat branch parallel to the sealing membrane of the second wall, and the second connecting member comprising a first flat branch parallel to the second fixing flange and a second flat branch parallel to the sealing membrane of the first wall. The first flat branch of the first connecting member is welded to the first fixed flange, the first flat branch of the second connecting member is welded to the second fixed flange, the first flat branch of the sealing corner member is welded to the second flat branch of the first connecting member, the second flat branch of the sealing corner member is welded to the second flat branch of the second connecting member, the sealing membrane of the first wall is welded to the second flat branch of the sealing corner member, and the sealing member of the second wall is welded to the first flat branch of the sealing corner member.

This corner structure allows the position of the corner sealing membrane to be adjusted by adapting the position of the fixing of the connecting member on the fixing flange to suit the desired position of the sealing corner member. By adjusting the position of the sealing corner member in this way, it is easily possible to adapt the corner structure to suit the thickness of the insulating barrier of the tank wall. In particular, the position of the first flat branch of the first connecting member on the first fixing flange makes it possible to adjust the distance between the second flat branch of the first connecting member and the supporting wall of the second wall, and therefore between the first flat branch of the sealing corner member and the supporting wall of the second wall. Similarly, the position of the second flat branch of the second connecting member on the second fixing flange makes it possible to adjust the distance between the second flat branch of the second connecting member and the supporting wall of the first wall, and therefore between the second flat branch of the sealing corner member and the supporting wall of the first wall.

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

According to some embodiments, the first fixing flange is also fixed to the support wall of the first wall, and the second fixing flange is fixed to the support wall of the second wall. In other words, the first fixing flange and the second fixing flange are in this case fixed to the junction of the support walls of the first wall and the second wall.

According to a particular embodiment, the sealing corner member includes a plurality of sections, two adjacent sections are sealingly connected to each other via a corrugated coupling protruding toward the inside of the tank, and the sealing membranes of the first wall and the second wall each include a set of corrugations protruding toward the inside of the tank and developing in a direction perpendicular to the edge corner, and each corrugation of the first wall and the second wall is aligned with the corrugation coupling of the sealing corner member. Such a corrugated coupling is simple to manufacture and can fit over the corrugations of the first wall and over the corrugations of the second wall, thereby ensuring the continuity of the sealing between the sealing corner member and the sealing membrane, while at the same time deforming with the sealing membrane.

According to a particular embodiment, the sealing corner member includes a plurality of sections, two adjacent sections are sealingly connected to each other via a corrugated coupling protruding toward the inside of the tank, and each of the sealing membranes of the first wall and the second wall includes a set of corrugations protruding toward the outside of the tank and extending in a direction perpendicular to the edge corner, and each corrugation of the first wall and the second wall is aligned with the corrugated coupling of the sealing corner member.

According to a particular embodiment, the corrugated coupling comprises a central part, a first bent end and a second bent end, the first bent end fitting on the corrugations of the sealing membrane of the first wall on the one hand and on the central part on the other hand, and the second bent end fitting on the corrugations of the sealing membrane of the second wall on the one hand and on the central part on the other hand. The fact that the corrugated coupling is three-part simplifies the connection with the sealing membrane and makes it possible to correct misalignments between the corrugations.

According to a particular embodiment, the first fixing flange extends parallel to the support wall of the first wall and the second fixing flange extends parallel to the support wall of the second wall.

According to a particular embodiment, at the edge corner, the support wall of the first wall and the support wall of the second wall together form a convex angle on the inside of the tank, the first fixing flange extends continuously with the support wall of the first wall, and the second fixing flange extends continuously with the support wall of the second wall.

According to a particular embodiment, at the edge corner, the support wall of the first wall and the support wall of the second wall together form a re-entrant angle on the inside of the tank, the first fixing flange extends parallel to the support wall of the first wall and at some distance therefrom, and the second fixing flange extends parallel to the support wall of the second wall and at some distance therefrom.

According to a particular embodiment, the insulating barrier of the first wall and/or the second wall comprises a plurality of lagging elements, each lagging element comprising a cover panel facing the inside of the tank, the inner surface of the lagging element bounding the edge corner comprises a discontinuity facing the sealing member, and a connecting plate is received within this discontinuity and lies flush with the inner surface of the lagging element and with the inner surface of the flat branch of the sealing corner member to which the sealing membrane is fixed, thereby forming a continuous flat support surface for the sealing membrane.

According to a particular embodiment, slots are formed in the first and/or second fixing flange, the slots being located at the height of the corrugated coupling. These slots make it possible to at least partially limit the mechanical stresses to which the weld between the corrugated coupling and the cross section of the sealing corner element is subjected.

According to a particular embodiment, the insulating barrier fixed to the supporting wall is a secondary insulating barrier, the sealing membrane fixed to the secondary insulating barrier is a secondary sealing membrane, the sealing corner member sealingly connected to the secondary sealing membrane of the first wall and the secondary sealing membrane of the second wall is a secondary sealing corner member, the first wall and the second wall further comprise, in the thickness direction of the tank from the outside to the inside, on top of the secondary insulating barrier and the secondary sealing membrane, a primary insulating barrier and a primary sealing membrane intended to be in contact with the liquid contained in the tank, and the corner structure further comprises a primary sealing corner member sealingly connected to the primary sealing membrane of the first wall and the primary sealing membrane of the second wall.

According to certain embodiments, the primary sealing corner member is secured to the secondary sealing corner member via one or more spacers.

According to a particular embodiment, the outer surface of the primary sealing corner member has a primary stud, each spacer includes at least one orifice through which the primary stud passes, the spacers are held against the outer surface of the primary sealing corner member by a primary nut mounted on the primary stud, the inner surface of the secondary sealing corner member has a secondary stud, the spacers have fixing tabs, the secondary studs are disposed between the fixing tabs of two adjacent spacers, a support plate including an orifice is mounted on the secondary studs, and the two adjacent spacers are held against the inner surface of the secondary sealing corner member mounted on the secondary studs by the secondary nut, by said support plate.

According to a particular embodiment, the secondary sealing membrane is a composite membrane and the secondary sealing corner member includes a plurality of sections, two adjacent sections being sealingly connected to each other via a composite sealing strip.

According to certain embodiments, a composite sealing strip is bonded between the corner members.

Such tanks may form part of an onshore storage facility, for example for storing liquefied gas, or may be located within floating coastal or offshore structures, in particular methane tankers, LPG carriers, floating storage and regasification units (FSRUs), floating product storage and offloading (FPSO) units, etc.

According to one embodiment, a vessel for transporting cryogenic liquid products comprises a hull and the aforementioned tank disposed within the hull.

According to one embodiment, the invention also provides a method for offloading such a vessel, in which the cryogenic liquid product is transferred from a floating or onshore storage facility to the vessel's hull or from the vessel's hull to the floating or onshore storage facility via insulated pipes.

According to one embodiment, the present invention also provides a transfer system for cryogenic liquid products, comprising a vessel as described above, a thermally insulated pipe arranged to connect a tank installed within the vessel's hull to a floating or onshore storage facility, and a pump for driving a flow of the cryogenic liquid product through the thermally insulated pipe from the floating or onshore storage facility to the vessel's tank or from the vessel's tank to the floating or onshore storage facility.

FIG. 1 is a perspective view of a tank according to one embodiment of the present invention. FIG. 2 is a perspective view of a portion of the tank of FIG. 1 showing the tank dome as viewed from inside the tank. 1A-1D are perspective views of a salient corner structure during one stage of its construction, according to one embodiment of the present invention. 1A-1C are perspective views of a salient corner structure during different stages of its construction, according to one embodiment of the present invention. 1A-1C are perspective views of a salient corner structure during different stages of its construction, according to one embodiment of the present invention. 1A-1C are perspective views of a salient corner structure during different stages of its construction, according to one embodiment of the present invention. FIG. 7 is a cross-sectional view of the corner structure of FIG. 6 . FIG. 13 is a cross-sectional view of a corner structure of a tank including two sealing membranes with two insulating barriers inserted therein according to an alternative form of embodiment of the present invention. FIG. 2 is a cross-sectional view in a plane of two studs secured to a secondary sealing corner member, illustrating one particular embodiment for securing the primary sealing corner member to the secondary sealing corner member. FIG. 2 is a cross-sectional view in a plane of two studs secured to a primary sealing corner member, illustrating one particular embodiment for securing the primary sealing corner member to a secondary sealing corner member. 1 is a cross-sectional view in a plane perpendicular to the primary sealing corner member and parallel to the edge corner, illustrating one step of one particular embodiment for mounting the primary sealing corner member onto the secondary sealing corner member. 1 is a cross-sectional view in a plane perpendicular to the primary sealing corner member and parallel to the edge corner, illustrating another step of one particular embodiment for mounting the primary sealing corner member onto the secondary sealing corner member. 1 is a cross-sectional view in a plane perpendicular to the primary sealing corner member and parallel to the edge corner, illustrating another step of one particular embodiment for mounting the primary sealing corner member onto the secondary sealing corner member. 1 is a cross-sectional view in a plane perpendicular to the primary sealing corner member and parallel to the edge corner, illustrating another step of one particular embodiment for mounting the primary sealing corner member onto the secondary sealing corner member. 1 is a cross-sectional view in a plane perpendicular to the primary sealing corner member and parallel to the edge corner, illustrating another step of one particular embodiment for mounting the primary sealing corner member onto the secondary sealing corner member. 13 illustrates an alternative embodiment for fastening the primary sealing corner member to the secondary sealing corner member. FIG. 4 is a cross-sectional view of a re-entrant corner structure according to another embodiment of the present invention. FIG. 1 is a cutaway view of a methane or propane tanker equipped with a tank according to one embodiment of the present invention. FIG. 2 is a partial perspective view of a salient corner structure in accordance with a particular embodiment of the present invention;

The invention will be better understood during the course of the following description of some particular embodiments of the invention, given by way of non-limiting example only with reference to the accompanying drawings, in which further objects, details, features and advantages thereof will become more clearly apparent.

The drawings are described below in the context of a support structure made up of the inner walls of a double hull of a ship for carrying liquefied gas. Such a support structure may in particular exhibit a polyhedral shape, for example a prismatic shape. Figure 1 shows such a support structure, whose longitudinal walls, comprising the upper wall 104, the lower wall 105 and the side walls 106, 107, 108, 109, 110, 111, run parallel to the longitudinal direction of the ship and form a polygonal cross section in a plane perpendicular to the longitudinal direction of the ship. The general orientation of a ship equipped with such a polyhedral tank is described, for example, with reference to figure 1 of patent FR 3008765.

The longitudinal walls 104, 105, 106, 107, 108, 109, 110, 111 are interrupted in the longitudinal direction of the vessel by transverse support walls 101, 103 that are perpendicular to the longitudinal direction of the vessel. The longitudinal walls 104, 105, 106, 107, 108, 109, 110, 111 and the transverse walls 101, 103 meet at re-entrant edge corners.

Each wall of the support structure supports a respective tank wall. In Figures 2-7, each tank wall is comprised of an insulating barrier that supports a sealing membrane in contact with the fluid stored in the tank, e.g., liquefied petroleum gas containing butane, propane, propene, etc., and having an equilibrium temperature between -50°C and 0°C.

The upper wall 104 includes a space called a tank dome 112, which is, for example, a rectangular parallelepiped-shaped space that protrudes upward.

As shown in more detail in FIG. 2, the tank dome 112 is defined by two transverse walls, front 113 and rear 114, and two side walls 115, 116 that extend vertically and project upward from the top wall 104. The tank dome 112 further comprises a horizontal cover, not shown in FIG. 2, intended to cover an opening formed between the front wall 113, rear wall 114 and side walls 115, 116 of the tank dome 112. The horizontal cover passes a series of tubes intended for the loading and unloading of the aforementioned liquids and gases. The upper longitudinal wall 104 and the wall of the tank dome 112 meet at a convex corner 100. The walls of the front wall 113 and side walls 115, 116 of the tank dome 112 meet at a concave corner 201.

Figure 3 is a view from inside the tank of the tank corner in the region of the tongue corner 100 between the first support wall 5 and the second support wall 25, which support the first tank wall 1 and the second tank wall 2, respectively. The first support wall 5 and the second support wall 25 form an angle α between them. The first tank wall 1 and the second tank wall 2 meet at the corner structure 10 of the tank.

In particular, as will be explained in relation to Figures 3 to 6, the corner structure 10 may be a convex corner structure (the angle α towards the inside of the tank between the two support walls is between 180° and 360°, which means that the edge corner is convex when viewed from inside the tank), which is the case, for example, of an edge corner between the upper longitudinal wall 104 and one of the front wall 113, the rear wall 114 and the side walls 115, 116 of the tank dome 112. Figures 3 to 6 show the particular case of the angle α measuring 270°.

As will be explained in relation to FIG. 13, the corner structure 10 may be a re-entrant corner structure (angle α is comprised between 0° and 180°), whereby the edge corner is concave when viewed from inside the tank, which is the case, for example, for edge corners between the longitudinal walls 104, 105, 106, 107, 108, 109, 110, 111 and the transverse walls 101, 103. FIG. 13 shows the particular case of angle α measuring 90°.

As shown in FIG. 6, the first tank wall 1 includes, in the thickness direction, a support wall 5, an insulating barrier 6 fixed to the support wall 5, and a sealing membrane 27 parallel to the support wall 5. The second tank wall 2 includes, in the thickness direction, a support wall 25, an insulating barrier 26 fixed to the support wall 25, and a sealing membrane 7 parallel to the support wall 25.

As shown in FIG. 3, the insulating barrier 6 of the first tank wall 1 is made up of a number of lagging elements 61 fixed to the first support wall 5. These lagging elements 61 together form a flat surface to which the sealing membrane 27 is fixed. Similarly, the insulating barrier 26 of the second tank wall 2 is made up of a number of lagging elements 61 fixed to the second support wall 25. These lagging elements 61 together form a flat surface to which the sealing membrane 7 is fixed. The lagging elements 61 are fixed to the support structure by any suitable means.

In one embodiment, the lagging element 61 is manufactured in the form of a box section fixed to the supporting wall by means of studs, as described in WO2017064413.

As shown in FIG. 6, the sealing membrane 7, 27 is composed of several metal plates juxtaposed to one another in an overlapping manner. These metal plates are preferably rectangular in shape. The metal plates are welded together to ensure the sealing of the sealing membrane. The metal plates are made, for example, of stainless steel or iron-based alloys with a high content of nickel or manganese, with a thickness of 0.5 to 1.5 mm.

In order to allow the sealing membrane to deform in response to the various stress loads to which the tank is subjected, in particular in response to thermal contraction resulting from the filling of the tank with liquefied gas, the metal plate comprises a number of corrugations 71, 72 oriented towards the inside of the tank. More specifically, the sealing membrane 7 comprises a first set of corrugations 71 and a second set of corrugations 72 forming a regular rectangular pattern. The first set of corrugations 71 are perpendicular to the edge corner 100 and the second set of corrugations 72 are parallel to the edge corner 100. Preferably, the corrugations 71, 72 run parallel to the edge of the rectangular metal plate. The distance between two successive corrugations 71, 72 of a set of corrugations is, for example, of the order of 300 mm to 800 mm, ideally 600 mm.

As shown in FIG. 3, the corner structure 10 includes a first fixing flange 11 extending from and continuous with the support wall 5 of the first tank wall 1, and a second fixing flange 211 extending from and continuous with the support wall 25 of the second tank wall 2.

It is also possible that the first fixing flange 11 does not extend continuously into the support wall 5 of the first tank wall 1 if it extends in a direction that is not parallel to the support wall 25 of the second wall 2. In other words, the first fixing flange 11 extends from the support wall 25 in a direction that is not parallel to said support wall 25. As shown in the figures, the first fixing flange 11 preferentially extends in a direction perpendicular to said support wall 25. In Figs. 1 to 10 and 11, the first fixing flange 11 extends from the junction of the support walls 5 and 25 in a direction parallel to the support wall 5. The row of lagging elements 61 of the insulating barrier 6 that bounds the edge corner 100 is arranged to form a space between the row of lagging elements 61 that bounds the edge corner 100 and the second fixing flange 211.

Similarly, the second fixing flange 211 may not extend continuously to the support wall 25 of the second tank wall 2 if it extends in a direction that is not parallel to the support wall 5 of the first wall 1. In other words, the second fixing flange 211 extends from the support wall 5 in a direction that is not parallel to said support wall 5. As shown in the figures, the second fixing flange 211 preferentially extends in a direction perpendicular to the support wall 5. In Figs. 1 to 10 and 11, the second fixing flange 211 extends from the junction of the support walls 5 and 25 in a direction parallel to the support wall 25. The row of lagging elements 61 of the insulating barrier 26 that bounds the edge corner 100 is arranged to form a space between the row of lagging elements 61 that bounds the edge corner 100 and the first fixing flange 11.

As shown in FIG. 4, the corner structure 10 comprises a first connecting member 12 and a second connecting member 212. The first connecting member 12 comprises a first flat branch 122 fixed to the fixing flange 11 and extending continuously therefrom, and a second flat branch 121 extending parallel to the support wall 25 in a space formed between the first fixing flange 11 and the row of lagging elements 61 of the insulating barrier 26 that bounds the edge corner 100. The first connecting member 12 may in particular be composed of a plurality of continuous sections 125. The second connecting member 212 comprises a first flat branch 2122 fixed to the fixing flange 211 and extending continuously therefrom, and a second flat branch 2121 extending parallel to the support wall 5 in a space formed between the second fixing flange 211 and the row of lagging elements 61 of the insulating barrier 6 that bounds the edge corner 100. The second connecting member 212 may in particular consist of a number of continuous sections 215. The connecting member 12, 212 is welded to the face of the fixing flange 11, 211 facing the insulating block 61 of the tank wall 1 or 2, although this is not a preference. As shown in FIG. 7, the connecting members 12 and 212 may be provided with a reinforcement between their two flat branches to increase their rigidity.

The space formed between the first fixing flange 11, the row of lagging elements 61 of the insulating barrier 26 that bounds the edge corner 100, the second flat branch 121 and the support wall 25 is advantageously filled with a lagging material such as glass wool or polyurethane foam. The space formed between the second fixing flange 211, the row of lagging elements 61 of the insulating barrier 6 that bounds the edge corner 100, the second flat branch 121 and the support wall 5 is advantageously filled with a lagging material such as glass wool or polyurethane foam.

As shown in FIG. 5, the corner structure 10 further includes a sealing corner member 13 fixed to the first fixed flange 11 via a first connecting member 12 on the one hand and to the second fixed flange 211 via a second connecting member 212 on the other hand.

The sealing corner member 13 is a plate, for example a metal plate, of a thickness greater than the thickness of the sealing membrane 7, 27. The sealing corner member 13 has a thickness, for example, between 3 mm and 10 mm. This thickness gives it sufficient rigidity to be self-supporting, although this is not necessarily the case for the sealing membrane 7, 27.

The sealing corner member 13 comprises a first flat branch 131 extending in the plane of the sealing membrane 7 of the second tank wall 2 and a second flat branch 132 extending in the plane of the sealing membrane 27 of the first tank wall 1. The first flat branch 131 is fixed to the first connecting member 12 (more specifically, welded to the second flat branch 121 of the first connecting member 12), and the second flat branch 132 is welded to the second connecting member 212 (more specifically, welded to the second flat branch 2121 of the second connecting member 212). As shown in FIG. 12, the sealing corner member 13 can have a reinforcement 134 on its outer surface.

Such a corner structure makes it possible to adjust the position of the sealing corner element 13, on the one hand, by adapting the fixing position of the first flat branch 122, 2122 of the connecting element 12, 212 on the fixing flange 11, 211, and, on the other hand, by adapting the fixing position of the flat branch 131, 132 of the sealing corner element 13 relative to the second flat branch 121, 2121 of the connecting element 12, 212. This adjustment of the position of the sealing corner element 13 makes it easily possible to adapt the corner structure to suit the thickness of the lagging element 61 of the insulating barrier 6, 26.

The first branch 131 of the sealing corner member forms a flat support for the sealing membrane 7 of the second tank wall 2, and the second branch 132 of the sealing corner member forms a flat support for the sealing membrane 27 of the first tank wall 1.

As shown in FIG. 6, the second wall sealing membrane 7 rests on the first branch 131 of the sealing corner member 13. The first wall sealing membrane 27 rests on the second branch 132 of the sealing corner member 13. To ensure continuity between the second wall sealing membrane 7 and the first wall sealing membrane 27 in the area of the corner structure 10, the sealing corner member 13 is sealingly connected to the second wall sealing membrane 7 and the first wall sealing membrane 27. For example, the second wall sealing membrane 7 may be welded to the first branch 131 of the sealing corner member 13 on which it rests, and the first wall sealing membrane 27 may be welded to the second branch 132 of the sealing corner member on which it rests.

5, the sealing corner member 13 may include multiple sections 135. The sections 135 of the sealing corner member may be overlappingly fixed to, for example, two adjacent sections 125 of the first connecting member 12 and two adjacent sections 215 of the second connecting member 212.

As shown in FIG. 6, two adjacent sections 135 can be sealingly connected to each other via a corrugated coupling 15. Each corrugation of the first set of corrugations 71 of the first and second walls is aligned with a corrugated coupling 15 of the sealing corner member. The corrugated coupling 15 fits over the corrugations 71 of the sealing membrane 27 of the first wall and over the corrugations 71 of the sealing membrane 7 of the second wall. The corrugated coupling 15 allows the sealing corner member 13 to deform together with the sealing membranes 7, 27.

As better seen in FIG. 7, the corrugated coupling 15 comprises a central portion 153, a first bent end 151 and a second bent end 152. The central portion 153 comprises two lateral tabs, one of which is welded to the central portion 133 of one section 155 of the sealing corner member and the other lateral tab is welded to the central portion of the adjacent section 155 of the sealing corner member. The first bent end 151 fits on the one hand onto the corrugation 71 of the first wall and on the other hand onto the central portion 153. The first bent end 151 comprises two lateral tabs, one of which is welded to one section 155 of the sealing corner member and the other lateral tab is welded to the adjacent section 155 of the sealing corner member, covering the overlapping area between the sealing corner member 13 and the sealing membrane 7 of the second tank wall 2. Similarly, the second bent end 152 has two lateral tabs, one of which is welded to a section 155 of the sealing corner member and the other lateral tab is welded to an adjacent section 155 of the sealing corner member, covering the overlap area between the sealing corner member 13 and the sealing membrane 27 of the first tank wall 1.

Such a corrugated coupling 15 is easy to manufacture and to fit over the corrugations 71 of the first wall and over the corrugations 71 of the second wall, thereby ensuring the continuity of the sealing between the sealing corner member 13 and the sealing membranes 7, 27 and at the same time being able to deform together with the sealing membranes 7, 27. The fact that the corrugated coupling 15 is in three parts simplifies the connection with the sealing membranes 7, 27 and makes it possible to correct the misalignment between the corrugations 71.

15, a slot 119 is optionally formed in the first fixing flange 11. Similarly, a slot 2119 is optionally formed in the second fixing flange 211. The slots 119 and/or 2119 can extend from the end of the fixing flange 11, 211 in particular in a direction perpendicular to the edge corner 100, in particular over a distance between 1/2 and 2/3 of the dimension of the fixing flange 11, 211 in that direction. The slots 119 and/or 2119 may be arranged in particular in the area of the corrugated coupling 15, i.e. typically every 600 mm. These slots 119, 2119 make it possible to relieve the mechanical stresses to which the weld between the corrugated coupling 15 and the cross section 135 of the sealing corner member 13 is subjected.

As shown in FIG. 5, each lagging element 61 comprises a cover panel facing the inside of the tank. By convention, regardless of the orientation of the tank wall with respect to the Earth's gravitational field, the adjectives "inside" or "interior" when applied to an element of the tank refer to the part of this element facing the inside of the tank, and the adjectives "outside" or "exterior" refer to the part of this element oriented towards the outside of the tank. On the side of the lagging element 61 immediately adjacent to the corner structure 10, the inner surface of the cover panel has a discontinuity 62 facing the connecting member 12, 212. As shown in FIG. 6, the connecting plate 63 is housed in the discontinuity 62 and is flush with the inner surface of the lagging element 61 and with the inner surface of the flat branch 132 of the sealing corner member to which the sealing membrane 27 is fixed, thereby forming a continuous support surface for the sealing membrane 27. Furthermore, the connecting plate 63 makes it possible to compensate for construction play that may occur during the construction of the tank. The connecting plate 63 may also have a discontinuity on its outer surface, such that the first branch 2122 of the connecting member 212, to which the flat branch 132 of the sealing corner member is fixed, rests within the discontinuity of the connecting plate 63. Thus, the connecting plate 63 bears against both the inner surface of the lagging element 61 and the inner surface of the first branch 2122 of the connecting member 212. Although the connecting plate 63 is described in relation to the first tank wall 1, it will be understood that a similar connecting plate may be provided on the second tank wall 2.

The above-described technique for forming a tank with a single sealing membrane can be used for various types of tanks, for example for constructing double membrane tanks for liquefied natural gas (LNG) in onshore facilities or floating structures such as methane tankers. In this context, it can be considered that the sealing membrane shown in the previous figure is a secondary sealing membrane, to which a primary insulating barrier and a primary sealing membrane also need to be added. In this way, the technique can also be applied to tanks with multiple insulating barriers and sealed membranes superimposed on one another.

Figure 8 shows two walls of a tank at an edge corner 100 according to an alternative form of embodiment, in which, in the thickness direction of the tank from outside to inside, the first tank wall 1 comprises a secondary insulating barrier 6 corresponding to the insulating barrier 6 described in relation to the previous figure, a secondary sealing membrane 27 corresponding to the sealing membrane 27 described in relation to the previous figure, a primary insulating barrier 6 and a primary sealing membrane 9 intended to be in contact with the liquid contained in the tank. Similarly, the second tank wall 2 comprises, in the thickness direction of the tank from outside to inside, a secondary insulating barrier 26 corresponding to the insulating barrier 26 described in relation to the previous figure, a secondary sealing membrane 7 corresponding to the sealing membrane 7 described in relation to the previous figure, a primary insulating barrier 26 and a primary sealing membrane 29 intended to be in contact with the liquid contained in the tank.

The primary insulating barrier 6, 26 and primary sealing membrane 29, 9 can be similar to the secondary insulating barrier 6, 26 and secondary sealing membrane 27, 7 and will not be described in further detail.

In a version not shown, the primary sealing membrane 9, 29 may be different from the secondary sealing membrane 7, 27, for example the corrugations of the secondary sealing membrane 7, 27 may face the outside of the tank wall.

In other versions not shown, the primary sealing membranes 9, 29 and the secondary sealing membranes 7, 27 have corrugations facing the outside of the tank wall.

In another version, not shown, the secondary sealing membrane 7, 27 is a composite sealing barrier. A composite connecting strip is joined on one side to the secondary sealing corner member 13 on the second flat branch 132 and on the other side to the composite sealing barrier present on top of the insulation block 61. Alternatively, the composite connecting strip may be joined on one side to the second connecting member 212 and on the other side to the composite sealing barrier present on top of the insulation block 61. To ensure the sealing of the secondary barrier, the composite sealing strip is bonded between the corner members 13. The composite sealing barrier may in particular be made of a composite material comprising three layers. The two outer layers are glass fiber cloth and the middle layer is a thin metal foil, for example an aluminum foil with a thickness of about 0.1 mm. This metal foil constitutes the secondary sealing barrier and is bonded to the insulation block 61 of the insulation barrier 6, 26. The composite connecting strip and the composite sealing strip may in particular be bonded using a polyurethane or epoxy adhesive.

A primary sealing corner member 913 is fixed to the secondary sealing corner member 13, which corresponds to the sealing corner member 13 described in relation to Figures 3 to 6. The primary sealing corner member 913 is similar to the sealing corner member 13 described in relation to Figures 3 to 6 and will not be described in detail. The primary sealing corner member 913 is sealingly connected to the primary sealing membrane 29 of the first tank wall 1 and the primary sealing membrane 9 of the second tank wall 2.

There are various possible ways to fasten the primary sealing corner member 913 to the secondary sealing corner member 13. As shown in Figures 9 to 11, the primary sealing corner member 913 can be fastened to the secondary sealing corner member 13, in particular, by a fastening member 30.

As shown in Figures 9 and 10, the fixing member 30 can include one or more spacers 32 secured to a primary sealing corner member 913, after which the assembly formed from the spacers 32 and the primary sealing corner member 913 is secured to the secondary sealing corner member 13.

As shown in FIG. 9, the inner surface of the secondary sealing corner member 13 may have secondary studs 31 fixed thereto by welding and/or screwing. FIG. 9 is a cross-sectional view in a plane of two studs 31 fixed to the secondary sealing corner member 13. In particular, each cross-section 135 of the secondary sealing corner member 13 may include two studs 31. Each stud 31 extends toward the inside of the tank perpendicular to the central portion 133 of the secondary sealing corner member 13.

As shown in FIG. 10, the outer surface of the primary sealing corner member 913 may have primary studs 35 fixed thereto by welding and/or screwing. FIG. 10 is a cross-sectional view in a plane of two studs 35 fixed to the primary sealing corner member 913. In particular, each cross-section of the primary sealing corner member 913 may include two studs 35. Each stud 35 extends perpendicular to the central portion of the primary sealing corner member toward the outside of the tank.

Next, one method of attaching the primary sealing corner member 913 to the secondary sealing corner member 13 will be described with reference to Figures 10b to 10f.

As shown in FIG. 10b, each cross section 9135 of the primary sealing corner member 913 includes one or more primary studs 35. The ends of the studs opposite the primary sealing corner member 913 include threads. Each spacer 32 includes one or more orifices 322 extending from its inner surface. In particular, each spacer 32 can include two orifices 322 extending from its inner surface.

As shown in FIG. 10c, each spacer 32 is mounted on one or more studs 35 such that each orifice 322 of the spacer allows a stud 35 to pass therethrough.

As shown in FIG. 10d, a nut 351 is fitted onto the threaded end of each stud 35. The inner surface of the spacer 32 is thus held pressed against the outer surface of the primary sealing corner member 913 by said nut 351. The holes 321 formed in the spacer 32 along the orifices through which the studs 31 pass are filled with insulating material after the nuts 351 are screwed onto the studs.

As shown in Figures 10e and 10f, the outer surface of the spacer 32 (i.e., the surface of the spacer 32 opposite the primary sealing corner member 913) is then secured to the inner surface of the secondary sealing corner member 13 by any means, such as bonding, riveting or screwing.

As shown in FIG. 10e, each cross section 135 of the secondary sealing corner member 13 includes one or more studs 31. The ends of the studs 31 opposite the secondary sealing corner member 13 are threaded. The spacers 32 have locking tabs 323 that extend in alignment with the outer surface of the spacer. The studs 31 are disposed between the locking tabs 323 of two adjacent spacers 32.

As shown in FIG. 10f, a support plate 33 including an orifice is attached to the stud 31. A nut 311 is attached to the threaded end of the stud 31. Thus, two adjacent spacers 32 are held pressed against the inner surface of the secondary sealing corner member 13 by said support plate 33.

Alternatively, according to an alternative form not shown, the stud 31 extending from the secondary sealing corner member 13 passes through a hole in the primary sealing corner member 913 and a nut is fitted onto the inner surface of the primary sealing corner member 913, the primary sealing corner member 913 being thus held by said nut against the inner surface of the spacer 32, the spacer 32 itself being held by said nut against the inner surface of the secondary sealing corner member 13.

11, the primary sealing corner member 913 may alternatively comprise two flat branches that form between them an angle equal to the angle α between the supporting walls of the edge corner, i.e. 90° in the case shown in FIG. 11. The primary sealing corner member 913 is therefore fixed to a support 37 that forms an angle equal to the angle α. Such a support 37 may be, for example, a beam with an isosceles triangular cross section, the base of the triangle being fixed to the outer surface of the spacer 32.

A similar corner structure can also be used for a re-entrant edge corner 201 of a tank. Figure 13 shows a tank edge corner between two tank walls forming an internal angle α of the order of 90°. Such a tank edge corner comprises a corner structure 510 similar to the corner structure 10 described in relation to Figures 2 to 6, with the difference that the first fixing flange 11 extends parallel to and at some distance from the support wall 5 of the first tank wall 1, and the second fixing flange 211 extends parallel to and at some distance from the support wall 25 of the second tank wall 2.

With reference to FIG. 14, a cutaway view of a methane or propane tanker 1070 shows a sealed insulated tank 1000 of prismatic general shape mounted within the vessel's double hull 1072. The tank's walls comprise at least one sealed barrier intended to be in contact with the liquefied gas contained within the tank and at least one insulating barrier disposed between the sealed barrier and the double hull 1072.

In a manner known per se, the off-loading pipe 1073 located on the upper deck of the vessel can be connected by suitable connectors to an offshore or port terminal for transferring the cargo of liquefied gas from or to the tank 1000.

14 shows an example of a marine terminal with a loading/unloading station 1075, an underwater pipe 1076, and an onshore facility 1077. The loading/unloading station 1075 is a fixed offshore facility with a movable arm 1074 and a tower 1078 supporting the movable arm 1074. The movable arm 1074 has a bundle of insulated flexible pipes 1079 that can be connected to the loading/unloading pipe 1073. The orientable movable arm 1074 is adapted to suit methane tankers of all sizes. A connecting pipe, not shown, extends inside the tower 1078. The loading/unloading station 1075 allows loading/unloading from the onshore facility 1077 to the vessel 1070 or from the vessel to the onshore facility 1077. The facility includes a liquefied gas storage tank 1080 and a connecting pipe 1081 connected to the loading/unloading station 1075 by an underwater pipe 1076. The underwater pipes 1076 allow the liquefied gas to be transferred between the offloading station 1075 and the onshore facility 1077 over long distances, such as 5 km, thereby allowing the vessel 1070 to remain off shore during offloading operations.

Pumps on board the vessel 1070 and/or pumps provided by the onshore facility 1077 and/or pumps provided by the loading/unloading station 1075 are used to generate the pressure required to transport the liquefied gas.

Although the present invention has been described with reference to some specific embodiments, it is very clear that the invention is not limited thereto but encompasses all technical equivalents of the described means and combinations thereof, provided that these are included within the scope of the present invention.
The use of the verbs "comprise", "have" and "include" and their conjugated forms does not exclude the presence of elements or steps other than those listed in a claim. The use of the indefinite article "a" or "an" in reference to an element or step does not exclude the presence of a plurality of such elements or steps, unless stated otherwise.

In the claims, any reference signs placed between parentheses shall not be construed as imposing a limitation on the claim.

LIST OF REFERENCE NUMERALS 1 first tank wall 2 second tank wall 5 first support wall 6 thermal insulation barrier, primary thermal insulation barrier, secondary thermal insulation barrier 7, 27 sealing membrane, secondary sealing membrane 9, 29 primary sealing membrane 10 corner structure 11 first fixing flange 12 first connecting element 13 sealing corner element, secondary sealing corner element 15 corrugated coupling 25 second support wall 25 support wall 26 primary thermal insulation barrier, secondary thermal insulation barrier 27 sealing membrane, secondary sealing membrane 29 primary sealing membrane 30 fixing element 31 stud, secondary stud 32 spacer 33 support plate 35 stud, primary stud 37 support 61 lagging element 62 discontinuity 63 connecting plate 71, 72 corrugation 100 tongue corner 101, 103 transverse support wall 104 upper wall 105 lower wall 106, 107, 108, 109, 110, 111 Side wall 112 Tank dome 113 Front wall 114 Rear wall 115, 116 Side wall 119 Slot 121 Second flat branch 122 First flat branch 125 Section 131 First flat branch 132 Second flat branch 133 Central portion 134 Stiffener 135 Cross section 151 First bent end 152 Second bent end 153 Central portion 155 Section 201 Re-entrant edge corner 211 Second fixing flange 212 Second connecting member 215 Section 311 Nut 321 Hole 322 Orifice 323 Fixing tab 351 Nut 510 Corner structure 913 Primary sealing corner member 1000 Insulated tank 1070 Ship 1072 Hull 1073 Pipe 1074 Movable arm 1075 Loading/unloading station 1076 Underwater pipe 1077 Onshore facility 1078 Tower 1079 Flexible pipe 1080 Liquefied gas storage tank 1081 Connecting pipe 2119 Slot 2121 Second flat branch 2122 First flat branch 9135 Cross section α Interior angle α Angle

Claims (12)

A sealed insulated tank (1000) for storing a fluid comprising a first wall (1) and a second wall (2), each of the first (1) and second (2) walls comprising, in a thickness direction, a support wall (5, 25), a thermal insulation barrier (6, 26) fixed to the support wall (5, 25), and a sealing membrane (7, 27) parallel to the support wall (5, 25) and fixed to the thermal insulation barrier (6, 26), the sealed insulated tank (1000) comprising, at an edge corner (100, 201) between the support wall (5) of the first wall (1) and the support wall (25) of the second wall (2), a corner structure (10), comprising: a first fixing flange (11) fixed to the support wall (5) of the second wall (2); a second fixing flange (211) fixed to the support wall (25) of the first wall (1);
a sealing corner element (13) fixed on the one hand to the first fixing flange (11) via a first connecting element (12) and on the other hand to the second fixing flange (211) via a second connecting element (212), the sealing corner element (13) being sealingly connected to the sealing membrane (27) of the first wall and to the sealing membrane (7) of the second wall,
said sealing corner element (13) comprises a first flat branch (131) extending in the plane of said sealing membrane (7) of said second wall (2) and a second flat branch (132) extending in the plane of said sealing membrane (27) of said first wall (1);
the first connecting member (12) comprises a first flat branch (122) parallel to the first fixing flange (11) and a second flat branch (121) parallel to the sealing membrane (7) of the second wall (2);
the second connecting member (212) comprises a first flat branch (2122) parallel to the second fixing flange (211) and a second flat branch (2121) parallel to the sealing membrane (27) of the first wall (1);
the first flat branch (122) of the first connecting member (12) is welded to the first fixing flange (11);
the first flat branch (2122) of the second connecting member (212) is welded to the second fixing flange (211);
the first flat branch (131) of the sealing corner member (13) is welded to the second flat branch (121) of the first connecting member (12), and the second flat branch (132) of the sealing corner member (13) is welded to the second flat branch (2121) of the second connecting member (212);
the sealing membrane (27) of the first wall (1) is welded to the second flat branch (132) of the sealing corner member (13);
the sealing membrane (7) of the second wall (2) is welded to the first flat branch (131) of the sealing corner member (13);
A sealed insulated tank, wherein at said edge corner (100), said supporting wall (5) of said first wall and said supporting wall (25) of said second wall together form a convex angle (α) on the inside of the tank, said first fixing flange (11) extending continuously into said supporting wall (5) of said first wall (1) and said second fixing flange (211) extending continuously into said supporting wall (25) of said second wall (2). The tank (1000) according to claim 1, wherein the sealing corner member (13) comprises a plurality of sections (135), two adjacent sections (135) are sealingly connected to each other via a corrugated coupling (15) protruding toward the inside of the tank, the sealing membranes (27, 7) of the first wall and the second wall each comprise a set of corrugations (71, 271) protruding toward the inside of the tank and extending in a direction perpendicular to the edge corner (100, 201), and each corrugation (71) of the first wall and the second wall is aligned with the corrugated coupling (15) of the sealing corner member. The tank (1000) according to claim 2, wherein the corrugated coupling (15) comprises a central portion (153), a first bent end (151) and a second bent end (152), the first bent end (151) fitting on the one hand onto the corrugations (71) of the sealing membrane (27) of the first wall and on the other hand onto the central portion (153), and the second bent end (152) fitting on the one hand onto the corrugations (71) of the sealing membrane (7) of the second wall and on the other hand onto the central portion (153). A tank (1000) according to any one of claims 1 to 3, wherein the first fixing flange (11) extends parallel to the support wall (5) of the first wall (1) and the second fixing flange (211) extends parallel to the support wall (25) of the second wall (2). The tank (1000) according to any one of claims 1 to 4, wherein the insulating barrier (6, 26) of the first wall (1) and/or the second wall (2) comprises a plurality of lagging elements (61), each of which comprises a cover panel facing the inside of the tank, the inner surface of the lagging elements (61) which bound the edge corner (100) comprises a discontinuity (62) which faces the sealing membrane (27), and a connecting plate (63) is housed in the discontinuity (62) and lies flush with the inner surface of the lagging elements (61) and with the inner surface of the flat branch (132) of the sealing corner member (13) to which the sealing membrane (27) is fixed, thereby forming a continuous flat support surface for the sealing membrane (27). The insulating barrier (6, 26) fixed to the supporting wall (5, 25) is a secondary insulating barrier, the sealing membrane (7, 27) fixed to the secondary insulating barrier (6, 26) is a secondary sealing membrane, the sealing corner member (13) sealingly connected to the secondary sealing membrane (27) of the first wall and the secondary sealing membrane (7) of the second wall is a secondary sealing corner member, and the first (1) and second (2) walls are further formed in a thickness direction of the tank from the outside to the inside. The tank (1000) according to any one of claims 1 to 5, comprising, on top of the secondary insulating barrier (6, 26) and the secondary sealing (7, 27), a primary insulating barrier (8, 28) and a primary sealing membrane (9, 29) intended to be in contact with the liquid contained in the tank, and the corner structure (10) further comprises a primary sealing corner member (913) sealingly connected to the primary sealing membrane (9) of the first wall and the primary sealing membrane (29) of the second wall. The tank (1000) of claim 6, wherein the primary sealing corner member (913) is fixed to the secondary sealing corner member (13) via one or more spacers (32). The tank (1000) according to claim 7, wherein the outer surface of the primary sealing corner member (913) has a primary stud (35), each spacer (32) includes at least one orifice through which the primary stud (35) passes, the spacers (32) are held against the outer surface of the primary sealing corner member (913) by a primary nut mounted on the primary stud (35), the inner surface of the secondary sealing corner member (13) has a secondary stud (31), the spacers (32) have fixing tabs (323), the secondary stud (31) is disposed between the fixing tabs (323) of two adjacent spacers (32), a support plate (33) including an orifice is mounted on the secondary stud (31), and the two adjacent spacers (32) are held against the inner surface of the secondary sealing corner member (13) by the support plate (33) by a secondary nut (311) mounted on the secondary stud (31). The tank (1000) according to any one of claims 6 to 8, wherein the secondary sealing membrane (27, 7) is a composite membrane, the secondary sealing corner member (13) includes a plurality of sections (135), and two adjacent sections (135) are sealingly connected to each other via a composite sealing strip. A vessel (1070) for transporting cryogenic liquid products, comprising a hull (1072) and a tank (1000) according to any one of claims 1 to 9 arranged within the hull. A transfer system comprising a vessel (1070) according to claim 10, a thermally insulated pipe (1073, 1079, 1076, 1081) arranged to connect the tank (1071) installed within the hull of the vessel to a floating or land-based storage facility (1077), and a pump for driving a flow of a cryogenic liquid product through the thermally insulated pipe from the floating or land-based storage facility to the vessel tank or from the vessel tank to the floating or land-based storage facility. A method for loading and unloading a vessel (1070) as described in claim 10, in which a cryogenic liquid product is transported from a floating or onshore storage facility (1077) to the hull of the vessel or from the hull of the vessel to a floating or onshore storage facility via a thermally insulated pipe (1073, 1079, 1076, 1081).