Watertight and thermally insulated tank with a corrugated connecting strip

Abstract

The invention relates to a tank in which at least one first tank wall (1) comprises at least one watertight membrane (9) and an insulating barrier (8) arranged between the watertight membrane (9) and a first load-bearing wall (5), in which the watertight membrane (9) comprises a plurality of strakes (15), a strake (15) comprising a flat portion (15B) and two longitudinal raised edges (15A), the strakes (15) being welded together in a watertight manner at the level of said raised edges (15A) to form expansion bellows (S), the tank wall (1) comprising a connecting strip (50) adapted to connect in a watertight manner at least one strake (15) to a portion of the membrane. According to the invention, said joining strip (50) comprises at least one corrugation (51) covering said expansion bellows (S) and a flat portion (52) applied against the flat portion (15B) of said at least one strake (15). Figure for the abbreviation: 1

Description

Title of the invention: Watertight and thermally insulating tank comprising a corrugated connecting strip. Technical field

[0001] The invention relates to the field of leak-proof and thermally insulated membrane tanks. In particular, the invention relates to the field of leak-proof and thermally insulated tanks for the storage and / or transport of low-temperature liquids, such as tanks for transporting Liquefied Natural Gas (LNG) at approximately -162°C at atmospheric pressure, ammonia (NH3) at -30°C at atmospheric pressure, or Liquefied Petroleum Gas (also called LPG) with a temperature, for example, between -50°C and 0°C. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank can be used for transporting liquefied gas or for receiving liquefied gas to serve as fuel for the propulsion of the floating structure. In the case of an onshore tank or a port storage structure, it can rest on the ground or the seabed and can be partially or completely buried. Technological background

[0002] For example, a sealed and thermally insulating tank integrated into a load-bearing structure is known from document WO2012072906. The tank comprises a first tank wall fixed to a first load-bearing wall and a second tank wall fixed to a second load-bearing wall joining the first load-bearing wall at an edge of the load-bearing structure. Each of the first and second tank walls comprises at least one sealed membrane and an insulating barrier arranged between the sealed membrane and the load-bearing wall. The sealed membrane comprises a plurality of flanges made of a low-expansion alloy. Each flange has a flat central portion resting on an upper surface of the insulating barrier and two raised edges projecting inward from the central portion of the tank. The flanges are juxtaposed and welded together in a sealed manner at the raised edges.

[0003] The tank wall further comprises a metal corner beam arranged parallel to the edge and anchored to the first and second load-bearing walls. The corner beam comprises a first flat flange parallel to the first load-bearing wall and a second flat flange parallel to the second load-bearing wall. The two flat flanges are rigidly connected to each other at a watertight bonding zone forming an angle of the watertight membrane. The strakes of the watertight membrane of each tank walls are connected in a watertight manner to the lateral wing of the beam extending parallel to this wall.

[0004] At one of the two walls, the watertight membrane further comprises a row of receiving strips welded to each of the first and second flat flanges. An end portion of the strakes of the watertight membrane is watertightly welded to a distal portion of the row of receiving strips.

[0005] The row of receiving strips is formed from a plurality of receiving strips comprising a flat central portion resting on the flat central portion of one of the strakes and two raised edges projecting inwards from the central portion of the tank. The receiving strips are juxtaposed and welded together watertight along each raised edge and welded to the strakes watertight along an edge weld. These welds are performed manually.

[0006] One disadvantage of this arrangement is that it requires a large number of manual edge welds which represent long and costly steps in the manufacture of the tank. Summary of the invention

[0007] One idea underlying the invention is to provide a sealed and thermally insulating tank in which the number of manual edge welds to be made is limited.

[0008] According to one embodiment, the invention provides a sealed and thermally insulating tank, integrated into a load-bearing structure comprising a first load-bearing wall and a second load-bearing wall joining the first load-bearing wall at an edge of the load-bearing structure, the tank comprising a first tank wall fixed to the first load-bearing wall and a second tank wall fixed to the second load-bearing wall, in which at least the first tank wall comprises at least one sealed membrane and an insulating barrier arranged between the sealed membrane and the first load-bearing wall, in which the sealed membrane comprises a plurality of strakes extending in a longitudinal direction perpendicular or oblique to the edge,a strake comprising a flat portion resting on an internal surface of the insulating barrier and two raised edges extending along the longitudinal direction of the strakes and projecting into the interior of the tank relative to the flat portion of the strake, the strakes being juxtaposed in a transverse direction perpendicular to the longitudinal direction and welded together watertight at said raised edges to form expansion bellows, the watertight membrane further comprising a portion of membrane disposed parallel to the edge and at a distance from a longitudinal end of the strakes and a connecting strip adapted to connect watertight the longitudinal end of at least one strake to said portion of membrane, in which said connecting strip, includes at least one corrugation covering said expansion bellows and at least one flat part applied against the flat portion of said at least one strake and against the membrane part.

[0009] Thanks to these characteristics, the number of edge welds is limited. The tank's construction requires a limited number of manual welds because the connecting strip can be lap-welded, without an edge weld, to an adjacent connecting strip. Furthermore, each connecting strip can have several corrugations and flat sections between the corrugations. The row of connecting strips is then no longer composed of as many receiving strips with raised edges as there are strakes, as is the case in the prior art. In addition, the flexibility of the watertight membranes, necessary for their mechanical resistance during thermal contraction and expansion, is preserved.

[0010] According to embodiments, such a tank may include one or more of the following characteristics.

[0011] According to one embodiment, said part of membrane is flat.

[0012] According to one embodiment, the tank further comprises a corner beam metallic arranged parallel to the edge of the load-bearing structure and anchored to the first and second load-bearing walls, the corner beam having a first lateral wing parallel to the first load-bearing wall and a second lateral wing parallel to the second load-bearing wall, the two lateral wings being connected to each other at a watertight bonding zone, in which said part of membrane comprises at least one of the first and second lateral wings of the corner beam.

[0013] According to one embodiment, said at least one or each corrugation of the joining strip has a first corrugation portion whose height relative to the flat parts of the joining strip is uniform, the first corrugation portion being located on the side of the strakes, and a second corrugation portion extending from the first corrugation portion and whose height relative to the flat parts of the joining strip gradually decreases until it reaches said flat parts, sealing said corrugation.

[0014] According to one embodiment, the joining strip is in the form of an elongated plate along a principal direction parallel to the edge, said at least one or each corrugation being formed by stamping or folding said elongated plate, and in which said at least one or each corrugation extends along the longitudinal direction, from an external principal edge of the elongated plate located on the side of the strakes.

[0015] Each connecting strip is thus formed from a single piece.

[0016] According to one embodiment, said at least one or each undulation extends to an internal principal edge of the elongated plate opposite the external principal edge.

[0017] According to one embodiment, the joining strip has at least two corrugations, for example three or four corrugations.

[0018] According to one embodiment, the waterproof membrane comprises a row of connecting strips, each connecting strip comprising at least one corrugation covering, or corrugations each covering, a said expansion bellows and at least one flat portion, or flat portions arranged between the corrugations, the connecting strips being juxtaposed along the direction of the edge and being lap-welded to each other.

[0019] According to one embodiment, the joining strip is welded in a watertight manner to the longitudinal end of the strakes and to the part of the membrane.

[0020] According to one embodiment, the insulating barrier of the first tank wall consists of parallelepiped-shaped heat-insulating boxes which are juxtaposed in a regular pattern.

[0021] According to one embodiment, the heat-insulating box comprises a load-bearing structure, for example made of plywood, and insulation, for example glass wool, wadding, rock wool, synthetic foams with a density of less than 70 kg / m3.

[0022] According to one embodiment, the heat-insulating box comprises a base panel and a lid panel with a polyurethane foam block preferably reinforced with fiberglass.

[0023] According to one embodiment, the first tank wall further comprises anchoring elements which anchor the heat-insulating boxes to the first load-bearing wall, each anchoring element comprising a base fixed to the first load-bearing wall and a coupler retained by the base and extending through the thickness of the insulating barrier and through the connecting strip.

[0024] The invention also proposes a vessel for the transport of a cold liquid product, the vessel comprising a double hull and a sealed and thermally insulated tank, as described above, disposed in the double hull.

[0025] The invention also proposes a transfer system for a cold liquid product, the system comprising a vessel as described above, insulated pipes arranged to connect the vessel's tank to a floating or land-based storage facility and a pump to drive a flow of cold liquid product through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

[0026] The invention finally proposes a method for loading or unloading a ship as described above, in which a cold liquid product is conveyed to through insulated pipelines to or from a floating or land-based storage facility to or from the ship's tank. Brief description of the figures

[0027] The invention will be better understood, and other objects, details, features and advantages thereof will become more apparent from the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation, with reference to the accompanying drawings.

[0028] The [Fig. 1] is a partial cutaway perspective view which schematically represents a sealed and thermally insulating tank at the level of a junction between two tank walls.

[0029] Fig. 2 is a perspective view of part of the tank of Fig. 1.

[0030] [Fig.3] is an enlarged view of part of [Fig.2].

[0031] Figure 4 is a perspective view of a joining element of a strip of connection of the tank of the [Fig.l].

[0032] [Fig.5] is a perspective view of a variant of the connecting element of [Fig.4],

[0033] Fig. 6 is a cross-sectional view of a corrugation of the connecting element of Fig. 4.

[0034] Fig. 7 is a schematic cutaway representation of a tank of a methane tanker and a loading / unloading terminal for this tank. Description of the implementation methods

[0035] The attached figures present a particular embodiment of a sealed and thermally insulating tank.

[0036] Figures 1 to 6 show a partial view of an embodiment of a sealed and thermally insulated tank for the storage and / or transport of a low-temperature liquid, 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 about -162°C at atmospheric pressure.

[0037] The fluid is in particular a cryogenic fluid transported at low temperatures. It may be a liquefied gas, in particular a liquefied natural gas (LNG), that is to say a gaseous mixture consisting mainly of methane as well as one or more other hydrocarbons, such as ethane, propane, n-butane, i-butane, n-pentane, i-pentane, neopentane, and nitrogen in small proportion.

[0038] The liquefied gas can also be ethane or liquefied petroleum gas (LPG), that is to say a mixture of hydrocarbons from the refining of petroleum consisting essentially of propane and butane.

[0039] Alternatively, the liquefied gas can be ammonia (NH3) stored at -30°C at atmospheric pressure.

[0040] The sealed and thermally insulating tank is integrated into a load-bearing structure. The load-bearing structure comprises a plurality of load-bearing walls 5, 25 defining the general shape of the tank, usually a polyhedral shape. It notably includes a first load-bearing wall 5 and a second load-bearing wall 25 joining the first load-bearing wall at an edge 101 of the load-bearing structure, forming a dihedral angle that could have different values. Here, an angle of 90° is shown.

[0041] Edge 101 extends along a direction z.

[0042] The load-bearing structure of the tank is here constituted by the inner hull of a double-hulled vessel. The first load-bearing wall 5 is, for example, a bottom wall of the vessel, while the second load-bearing wall 25 is, for example, a transverse bulkhead, which partially defines a compartment in the inner hull of the vessel.

[0043] The tank comprises a first tank wall 1 fixed to the first load-bearing wall 5 and a second tank wall 2 fixed to the second load-bearing wall 25.

[0044] Each of the tank walls 1, 2 extends parallel to the corresponding load-bearing wall.

[0045] Each of the first and second tank walls 1, 2 comprises a multilayer structure.

[0046] In relation to [Fig. 1], the multilayer structure of each of the first and second tank walls 1, 2 is now described.

[0047] The first tank wall 1 comprises, in the thickness direction XI of the first tank wall 1, from the outside to the inside, a first secondary thermally insulating barrier 6 resting against the first load-bearing wall 5, a first secondary waterproof membrane 7, a first primary thermally insulating barrier 8 and a first primary waterproof membrane 9 intended to be in contact with the fluid stored in the tank.

[0048] Similarly, the second tank wall 2 comprises, in the thickness direction X2 of the second tank wall 2, from the outside to the inside, a second secondary thermally insulating barrier 26 resting against the second load-bearing wall 25, a second secondary waterproof membrane 27, a second primary thermally insulating barrier 28 and a second primary waterproof membrane 29 intended to be in contact with the fluid stored in the tank.

[0049] The first and second primary thermally insulating barriers 8, 28 and the first and second secondary thermally insulating barriers 6, 26 are each made up of heat-insulating elements and more particularly of parallelepiped heat-insulating boxes 10 which are juxtaposed in a regular pattern.

[0050] These heat-insulating boxes 10 constitute insulating blocks.

[0051] These insulating blocks generally have a parallelepiped shape with two main faces parallel to the load-bearing wall 1, 2 on which the corresponding tank wall is fixed.

[0052] Each thermal insulation box 10 is held on the first or second load-bearing wall 5, 25 by means of anchoring devices 20 which can be made in many ways according to known technique and for example as described in publication FR2973098. The anchoring devices 20 may include retaining devices arranged at the corners of the insulating blocks which anchor four adjacent insulating blocks in the corresponding load-bearing wall 5, 25.

[0053] Such retaining devices can be made in different ways and are described for example in more detail in document WO2019 / 110894.

[0054] In the example described and illustrated, the anchoring members 20 anchor the heat-insulating panels 10 of the secondary insulating barrier and the heat-insulating panels 10 of the primary insulating barrier to the underlying load-bearing wall. Each anchoring member 20 comprises a base 97 fixed to the load-bearing wall, a secondary coupler 99 retained by the base and extending through the thickness of the secondary insulating barrier to retain the heat-insulating panels 10 of the secondary insulating barrier, and a primary coupler 98 surmounting the secondary coupler 99 and extending into the thickness of the primary insulating barrier to retain the heat-insulating panels 10 of the primary insulating barrier.

[0055] Each connecting strip 55 has an opening for this purpose, intended to allow the passage of the primary coupler 98 of the anchoring member 20 (not shown in Figures 4 and 5). The primary coupler 98 has a flange welded tightly around the opening to restore the seal of the connecting strip 55.

[0056] The main faces of the heat-insulating boxes 10 facing the interior of the tank form the internal surface of the primary or secondary insulating barrier.

[0057] Various techniques are known for making such heat-insulating elements. For example, here, each heat-insulating box 10 constitutes a box formed from plywood panels assembled together using a known technique to form a load-bearing structure and filled with heat-insulating material.

[0058] The heat-insulating box 10 includes a bottom panel 11 and a lid panel 12. Side panels 13 and internal walls 14 extend between the bottom panel 11 and the lid panel 12 in the thickness direction of the tank wall.

[0059] The side panels 13, bottom panel 11 and lid panel 12, and the internal walls 14 define spaces in which the heat-insulating lining made of a thermally insulating material is installed. Different materials Thermally insulating materials such as glass wool, wadding, rock wool, expanded perlite, expanded polystyrene or synthetic polymer foams with a density of less than 70 kg / m3 can be used as insulating lining.

[0060] Such insulating blocks are described in more detail in document WO2021239767.

[0061] According to another specific embodiment of the insulating blocks, a plywood-thermally insulating foam-plywood sandwich structure can be used. One or more layers of foam are arranged between a cover panel and a base panel made of plywood.

[0062] The lid panels 12 and bottom panel 11 are glued onto the foam layer(s).

[0063] The thermally insulating foam is, for example, a polyurethane foam, optionally reinforced with glass fibers, having, for example, a density of the order of, or even greater than, 130 kg.m3.

[0064] The foam layer has at each of its corners a recess intended to receive the retaining element.

[0065] The heat-insulating boxes 10 of the first primary thermally insulating barriers 8 and secondary 6 respectively carry the first primary membrane 9 and the first secondary membrane 7 of the first tank wall 1.

[0066] The heat-insulating boxes 10 of the second primary thermally insulating barriers 28 and secondary 26 respectively carry the second primary membrane 29 and the second secondary membrane 27 of the second tank wall 2.

[0067] As shown in [Fig.1], the heat-insulating boxes 10 forming the first and second secondary insulating barriers 6, 26 are here arranged in alignment with the heat-insulating boxes forming the first and second primary insulating barriers 8, 28.

[0068] Alternatively, the thermal insulation panels of the primary insulating barrier can be arranged in a staggered pattern, straddling four thermal insulation panels of the adjacent secondary insulating barrier. In this case, the fixing elements protruding from the secondary insulating barrier are provided.

[0069] The first and second secondary membranes 7, 27 and primary membranes 9, 29 are, for example, made up of a series of elongated metal plates along a longitudinal direction L1, L2 and called strakes 15. The longitudinal direction L1, L2 of the strakes extends perpendicularly or obliquely to the edge 101. Each strake 15 comprises a flat central portion 15B delimited by two raised longitudinal edges 15A extending parallel to the longitudinal direction L1, L2 of the strake 15 and by two end edges extending perpendicularly to the direction Longitudinal L1, L2. The strakes 15 are juxtaposed parallel to each other in a transverse direction perpendicular to the longitudinal direction. They are arranged alternately with weld supports 16 in the form of elongated flat metal strips.

[0070] Each strake 15 typically extends over several tens of meters along its longitudinal direction L1, L2.

[0071] The weld supports 16 are arranged so as to extend in a plane substantially perpendicular to the plane in which the central flat portion 15B of the strakes 15 extends.

[0072] The strakes 15 and the weld supports 16 are made of an alloy with a low coefficient of expansion. The strakes 15 and the weld supports 16 are, for example, made of Invar®, i.e. an iron and nickel alloy whose coefficient of expansion is typically less than or equal to 2.106 K1, preferably between 0.5.106 and 2.106 K1 or for example made of an iron and manganese alloy whose coefficient of expansion is typically on the order of 7.106 K1 to 9.106 K1. In this case, the strakes may have, for example, a thickness on the order of 0.5 to 1.5 millimeters (mm), for example.

[0073] The first and second secondary membranes 7, 27 and primary membranes 9, 29 typically have a thickness between 0.5 and 1.5 mm, and preferably 0.7 mm.

[0074] The central flat portion 15B of each strake 15 rests on an internal surface of the insulating barrier and the two longitudinal raised edges 15A protrude towards the inside of the tank relative to the central flat portion 15B of the strake 15. More precisely, here, the central flat portions 15B of the strakes 15 rest against the cover panels 12 of the heat-insulating boxes 10 of the corresponding insulating barrier.

[0075] The longitudinal raised edges 15A of the strakes 15 extend substantially perpendicularly to the central flat portion 15B.

[0076] The strakes 15 and the weld supports 16 are welded together in a watertight manner at the level of said raised longitudinal edges 15A to form expansion bellows S between each pair of two neighboring strakes 15.

[0077] Over these long lengths, watertight welds between the raised longitudinal edges 15A of the strakes 15 and the weld supports 16 interposed between them can be made in the form of straight weld beads parallel to the wall using an electric welding machine described, for example, in FR-A-2172837 or FR-A-2140716. Such a welding machine, of relatively significant weight, moves along the weld line while being held against the plates whose raised longitudinal edges it is welding. This holding is achieved Thanks to the forward tilt of the machine's drive roller axis in its direction of travel, the welding machine is adapted to perform welds on all walls of the tank, including the vertical walls and the ceiling, while remaining constantly and firmly pressed against the metal sheet whose raised longitudinal edges it is welding.

[0078] The weld support 16, interposed between two strakes 15, terminates at or slightly before the longitudinal end edge 15C of the strakes 15. However, from an end point 16A of the weld support 16, the upper portion of this support is trimmed flush so that the height of the weld support 16 is the same as the height of the raised longitudinal edges 15A, which facilitates the creation of a watertight edge weld between them.

[0079] Along the entire central portion of the tank wall, and up to near the longitudinal end edge 15C of the strakes, the watertight connection between the upturned longitudinal edges 15A of the strakes 15 and the weld supports 16 is achieved by straight weld beads, which extend approximately halfway up the upturned longitudinal edges 15A on either side of the weld support 16. These weld beads extend strictly parallel to the support surface on which the watertight barrier rests, because the welding machine that produces them advances by rolling on this surface and is firmly pressed against it. However, due to insufficient space, the roller welding machine must be stopped before reaching the corner of the tank.

[0080] At the longitudinal end edge 15C of the strakes 15, the raised longitudinal edges 15A and the weld support 16 are welded together by an edge weld, along the top of the two raised longitudinal edges 15A.

[0081] In order to create a watertight connection between the mid-height weld bead and the edge weld, a rounded cut 151 is made in the raised longitudinal edges 15A of the strakes 15 to lower their upper edge until it meets the mid-height weld bead. It is then possible to extend the edge weld into the bottom of this rounded cut 151 until it continuously joins the weld bead. This is achieved as described in more detail in document WO 2012072906.

[0082] The weld supports 16 are each retained to the underlying thermally insulating barrier 6, 8, for example by being housed in grooves, in the shape of an inverted T or a J, provided in the cover panels 12 of the heat-insulating boxes 10. Further details on the realization of such a membrane can be found in publication FR2968284.

[0083] As can be seen in [Fig. 1], the striations 15 of the first primary membrane 9 and secondary membrane 7 of the first tank wall 1 are oriented such that their longitudinal direction L1 extends orthogonally to the edge 101, while that the struts 15 of the second primary membranes 29 and secondary membranes 27 of the second wall of tank 2 are oriented in such a way that their longitudinal direction L2 extends parallel to the edge 101.

[0084] We now describe in more detail a corner area of ​​the tank. [Fig. 1] is a perspective view of a junction area 100 between the first tank wall 1 (extending in a yz plane) and the second tank wall 2 (extending in an xz plane).

[0085] At the junction 100, the load-bearing wall 5 of the first wall 1 and the load-bearing wall 25 of the second wall 2 meet at the edge 101 and the first and second secondary membranes 7, 27 and primary membranes 9, 29 of the two tank walls 1, 2 are connected by an anchoring device allowing the first and second secondary sealing membranes 7, 27 and primary membranes 9, 29 to be anchored on the one hand to the load-bearing wall 5 of the first tank wall 1 and on the other hand to the load-bearing wall 25 of the second tank wall 2. The first and second secondary sealing membranes 7, 27 of the two tank walls 1, 2 and the first and second primary sealing membranes 9, 29 of the two tank walls are connected in a watertight manner by the corner beam 17.

[0086] More particularly, the first secondary membranes 7 and primary membranes 9 of the first wall 1 are anchored perpendicularly on the first load-bearing wall 25 of the second wall of the tank 2. Similarly, the second secondary membranes 27 and primary membranes 29 of the second wall 2 are anchored perpendicularly on the first load-bearing wall 5 of the first wall of the tank 1.

[0087] The anchoring device allows the tensile forces resulting from the thermal contraction of the first and second secondary membranes 7, 27 and primary membranes 9, 29 to be absorbed. The anchoring device also allows the forces resulting from the deformation of the hull and in particular from the bending of the longitudinal wall of a ship corresponding to the beam effect of the ship.

[0088] The anchoring device comprises the elongated angle beam 17 having a hollow central core with a parallelogram cross-section, here square. The first and second load-bearing walls 5, 25 form a right angle. Like the waterproof membranes, the angle beam 17 can be made of an alloy with a low coefficient of expansion, for example, with sheets with a thickness between 1 and 1.5 mm.

[0089] To hold the corner beam 17 on each side of the edge 101, each of the first and second load-bearing walls 5, 25 has a primary anchor plate 30 and a secondary anchor plate 31. The distance from the secondary anchor plates 31 to the edge 101 corresponds to the thickness of the secondary insulation barrier. The distance between the anchor plates 30 and 31 corresponds to the thickness of the primary insulation barrier. The For example, primary anchor plates 30 and secondary anchor plates 31 have a thickness between 6 and 12 mm and preferably 8 mm.

[0090] In the embodiment of [Fig. 1], the corner beam 17 comprises, for example, four metal cross profiles connected by metal plates to form a square-section tube 36. This square-section tube 36 is connected by first anchoring flanges 37A, 37B to the first load-bearing wall 1 and by second anchoring flanges 37C, 37D to the second load-bearing wall 2. The first anchoring flanges 37A, 37B extend parallel to the second load-bearing wall 2 and the second anchoring flanges 37C, 37D extend parallel to the first load-bearing wall 1. The first and second anchoring flanges anchor the corner beam 17 to the load-bearing structure.

[0091] To make the angle beam 17 all along the edge 101, it is preferable to use several successive segments, the length of which is adapted to the handling conditions, for example 1 to 3 meters per segment.

[0092] In addition, preferably insulating pieces 40, 41 are provided, housed between the load-bearing walls and the corner beam and / or inside the corner beam when the latter is in the form of a square-section tube.

[0093] The corner beam 17 further comprises two first primary lateral wings 18A and secondary 18B parallel to the first load-bearing wall 1 and two second primary lateral wings 19A and secondary 19B parallel to the second load-bearing wall 2.

[0094] The first primary and secondary lateral wings 18A, 18B of the first tank wall 1 allow the attachment of the first primary 9 and secondary 7 sealing membranes.

[0095] The second primary and secondary lateral wings 19A, 19B of the second tank wall 2 allow the attachment of the second primary 29 and secondary 27 sealing membranes.

[0096] The two primary side wings 18A, 19A on the one hand, and the two secondary side wings 18B, 19B allowing the attachment of the first and second secondary sealing membranes 7, 27 on the other hand, are linked to each other at the level of a sealing connection zone of the corner beam 17.

[0097] In the case of the embodiment shown in the figures, the sealed connection area has a stepped shape, comprising the metal plates of the corner beam 17 forming the internal angle of the corner beam oriented towards the center of the tank.

[0098] Each lateral wing 18A, 18B, 19A, 19B of the angle beam 17 extends in line with one of the anchor wings 37A, 37B, 37C, 37D.

[0099] The first primary and secondary lateral wings 18A, 18B of the angle beam 17 form a membrane portion arranged parallel to the edge 101 and at a distance from a longitudinal end 15C of the strakes 15 along the longitudinal ends of the strakes 15 of the first primary and secondary membranes of the first tank wall 1. The first lateral wings 18A, 18B are here entirely flat. Their free edges do not include any notches.

[0100] Each of the first and second lateral wings 18A, 18B, 19A, 19B of the angle beam 17 here includes a connecting part constituted by the free edge of each of the first and second lateral wings 18A, 18B, 19A, 19B of the angle beam 17.

[0101] In the embodiment shown in the figures, the first primary and secondary sealing membranes 9, 7 of the first tank wall 1 further include a connecting strip 55 adapted to connect in a watertight manner the longitudinal end 15C of the strakes 15 of the first primary and secondary sealing membranes 9, 7 to the corresponding first primary and secondary lateral wings 18A, 18B of the corner beam 17.

[0102] This connecting strip 55 includes corrugations 51 each covering a said expansion bellows S formed by two adjacent strakes 15 and flat parts 52 arranged between the corrugations 51 and applied against the central flat portions 15B of the strakes 15 ([Fig.2]).

[0103] The arrangement of the first secondary membrane 7 is described below. The arrangement of the first primary membrane 9 is similar here.

[0104] The connecting strip 55 is in the form of an elongated plate along a main direction DP. It has two main edges 54A, 53A parallel to the main direction DP and two transverse end edges 56, 57 located at the ends of the connecting element 55 along this main direction DP.

[0105] Each connecting strip 55 further has two flat end portions 60 which extend longitudinally between the corrugation 51 nearest to an end edge and that end edge (Figures 4 and 5).

[0106] The connecting strip 55 is formed from a single piece.

[0107] The internal main edge 53A is close to the angle beam 17, while the external main edge 54A is oriented towards the strakes 15.

[0108] Each corrugation 51 of the connecting strip 55 extends along a transverse direction T to the main direction DP of the connecting strip 55, from one main edge to another main edge of the plate forming the connecting strip 55, i.e. here between the inner main edge 53A and the outer main edge 54A. This is visible for example in [Fig.2].

[0109] The connecting strip 55 is fixed to the insulating blocks of the underlying insulating barrier by the anchoring elements 20 ([Fig.3]) which pass through it.

[0110] The connecting strip 55 is continuously and tightly welded to the connecting part of the first secondary side wing 18B of the angle beam 17 along its internal main edge 53A and is welded to an end portion of the strakes 15 of the first secondary membrane 7 along its external main edge 54A.

[0111] The weld follows the outer main edge 54A all the way along, including along the undulations 51.

[0112] The flat part 52 of the connecting strip 55 extends parallel to the connecting part of the secondary lateral wing 18B of the angle beam 17 and parallel to the central flat portion 15B of the strakes 15 of the secondary membrane 7.

[0113] For this purpose, the main external edge 54A of the connecting strip 55 covers an end edge 15C of each strut 15 ([Fig.3]).

[0114] Similarly, the inner longitudinal edge 53A of the connecting strip 55 covers the free edge of the secondary lateral wing 18B of the angle beam 17.

[0115] In practice, the first secondary waterproof membrane 7 comprises a row 50 of connecting strips 55.

[0116] The row of connecting strips 55 has two longitudinal edges 53, 54 formed by the main internal and external edges 53A and 54A of the connecting strips 55.

[0117] The connecting strips 55 are welded to each other along their transverse end edges 56, 57 to form the row 50 of connecting strips 55. One of the transverse end edges 57 of each connecting strip 55 is clinched welded to the other transverse end edge 56 of another adjacent connecting strip 55.

[0118] For this purpose, the transverse end edge 57 here forms a sidewalk in order to cover the other transverse end edge 56 of the neighboring connecting element (figures 4 and 5) while allowing the adjacent flat end parts 60 of two successive connecting elements 55 to extend in the same plane.

[0119] This weld is made manually. It is a classic lap weld.

[0120] Each connecting strip 55 of the row 50 of connecting strips 55 comprises at minus two corrugations 51, as is the case in the example of Figures 1 to 4, preferably at least three corrugations 51, as shown for example in the variant of [Fig. 5]. The number of connecting strips needed to form the row 50 of connecting strips 55 is thus limited, as is the number of welds required to manufacture the row 50 of connecting strips 55.

[0121] Alternatively, it may be envisaged that at least one joining strip comprises a single corrugation and at least one flat part, or two flat parts located on either side of the corrugation.

[0122] When the connecting strip has two corrugations, its length is equal to the dimension of each heat-insulating box along the main direction DP.

[0123] On the examples of connecting strips 55 shown in figures 4, 5 and 6, the dimensions are as follows: - the gap DI between two successive corrugations 51 is equal to 500 mm to the nearest 20 mm, - the thickness El of the plate forming the joining strip 55 is equal to 1.5 mm to the nearest 0.5 mm, - the height H1 between the inner face of a flat part of the connecting strip 55 and the end of the straight part of the corrugation 51 is equal to 20 mm to the nearest 3 mm, - the radius of curvature RI of the base of the corrugation 51 is equal to 3.5 mm to the nearest 0.5 mm, - the radius of curvature R2 of the crest of the undulation 51 is equal to 1.2 mm to within 0.5 mm, - the width D2 of the interior space delimited by the undulation is equal to 2.4 mm to within 0.5 mm.

[0124] The [Fig.6] is a profile view of the corrugation 51 seen from the outer main edge 54A of the connecting strip, along the transverse direction T of the connecting strip 55.

[0125] The end edge 15C of each strake 15 has a complex profile because each raised longitudinal edge 15A of the strake 15 extends to this end edge 15C. The raised longitudinal edge 15A has a constant height over its entire length.

[0126] The main direction DP of the connecting strip 55 is perpendicular to the longitudinal direction L1 of the strakes 15, such that the transverse direction T of the undulations 51 of the connecting strip 55 is parallel to the longitudinal direction L1 of the strakes 15 ([Fig.5]).

[0127] This main direction is parallel to edge 101.

[0128] The undulations 51 of the joining strip 55 are spaced by the distance separating two expansion bellows S of the secondary membrane 7, i.e. approximately the distance between two raised longitudinal edges 15A of the welt 15.

[0129] The undulations 51 of the connecting strip 55 are thus arranged in alignment with the raised longitudinal edges of the strakes 15 to terminate the expansion bellows S, at a distance from the watertight connection zone of the corner beam 17.

[0130] Each corrugation 51 of the connecting strip 55 extends from the corresponding strake 15 towards the connecting part of the angle beam 17, over a distance preferably greater than 300 mm and less than 600 mm, for example equal to 400 mm. This distance is here equal to the width of the connecting strip 55 because the corrugations 51 extend from the outer main edge 54A to the inner main edge 53A of the connecting strip.

[0131] Alternatively, the undulations may extend over a length less than the width of the joining strip measured between its main internal and external edges.

[0132] Each corrugation 51 has a shape adapted to cover the longitudinal end of an expansion bellows and to extend it onto the connecting strip 55, in the direction of the connection area of ​​the angle beam 17.

[0133] Each undulation 51 is here formed by two lateral walls 511,512 ([Fig.6]) which rise perpendicularly to the flat part 52 of the connecting strip 55. They are connected to the flat part 52 by rounded elbows 513 and connected to each other at the top by a rounded ridge 514.

[0134] More specifically, as is particularly visible in [Fig.6], each undulation 51 of the connecting strip 55 is formed with the connecting strip 55. It is for example produced by stamping or folding the metal plate forming each connecting strip 55 of the row 50 of connecting strip 55.

[0135] The receiving strip is for example made of one of the iron and nickel alloys described above.

[0136] A first stamping tool is used to make the corrugations 51 of the connecting element 55, and a second tool is used to ensure the accuracy of the internal dimensions of each corrugation 51, here 2.4 mm wide over the entire height of the straight part of the corrugation, with an accuracy of 0.5 mm.

[0137] Each corrugation 51 of the connecting strip 55 has a first portion of corrugation 51A whose height relative to the flat parts of the connecting strip 55 is uniform, this first portion of corrugation 51A being located on the side of the strakes 15, and a second portion of corrugation 51B whose height relative to the flat parts decreases progressively towards the corner beam 17 until it joins said flat parts 52 by sealing said corrugation 51.

[0138] The first part 51A of the corrugation 51 internally delimits a housing having a shape adapted to conform to the contour of the expansion bellows S formed between two adjacent strakes 15 when they are covered by the connecting strip 55. The second part 51B of the corrugation 51 extends the first portion of the corrugation 51A and continuously connects the first part 51A of the corrugation 51 to the main internal edge 53A of the connecting strip 55. The second part 51B of the corrugation 51 extends, for example, over a distance of between 50 and 90 mm.

[0139] If the corrugation is shorter than the width of the connecting strip, the second part of the corrugation continuously connects the first part of the corrugation to the flat part of the connecting strip. The free end of the second part of the corrugation, along the longitudinal direction of the corrugation, may gradually reach, along an inclined direction, the level of an inner face, oriented towards the inside of the tank, of the flat part 52, or gradually reach, along an inclined direction, a height of between 1 and 5 millimeters above the flat part 52. above the inner face of the flat part 52 and join this inner face along a direction perpendicular to the flat part.

[0140] The second part 5IB of the corrugation 51 can be formed by cutting the corrugation profile obtained after stamping, pinching the two lateral walls 511, 512 of the corrugation, and welding their crests together. Adding material can also be considered to weld the free edges of the lateral walls of the corrugation along the second part of the corrugation 51.

[0141] This second part 51B of the undulation 51 closes the expansion bellows S near the angle beam 17.

[0142] As mentioned previously, the first primary membrane 9 of the first tank wall 1 here has a row 50 of connecting strips 55 in every respect similar to that described above for the first secondary membrane 7. The row 50 of connecting strips of the first primary membrane is welded on one side to the longitudinal ends of the strakes of the first primary membrane and on the other side to the free edge of the first primary lateral wing 18 A.

[0143] A corner portion of a tank has been described here, the two tank walls of which each comprise two primary and secondary insulating barriers and two primary and secondary sealing membranes. Alternatively, the first tank wall may comprise only one insulating barrier and one sealing membrane such as that described above.

[0144] To manufacture the sealed and thermally insulating tank described above, the following steps are carried out, for example: - the connecting strips 55 are hermetically welded together by a lap weld of a transverse end edge 57 of a connecting strip 55 forming a ledge which overlaps on the transverse end edge 56 of a flat end part 60 of another neighbouring connecting strip 55, so as to form the row 50 of connecting strips 55, - the connecting strip 55 is positioned so as to accommodate the expansion gussets S formed by the strakes 15 in the undulations 51 of the connecting strip 55, - the outer main edge 54A of each connecting strip 55 is hermetically welded to a longitudinal end 15C of the strakes 15, - the main internal edge 53A of each connecting strip 55 is hermetically welded to the free edge of the lateral wing 18A, 18B of the corresponding angle beam 17.

[0145] These steps can be carried out in this order or in another order, for example: - The connecting strip 55 is positioned so as to house the expansion gussets S formed by the strakes 15 in the undulations 51 of the connecting strip 55, - the outer main edge 54A of each connecting strip 55 is hermetically welded to a longitudinal end 15C of the strakes 15, - the main internal edge 53A of each connecting strip 55 is hermetically welded to the free edge of the lateral wing 18A, 18B of the corresponding angle beam 17, - the connecting strips 55 are hermetically welded together by a lap weld of a transverse end edge 57 of a connecting strip 55 forming a sidewalk which covers on the transverse end edge 56 of a flat end part 60 of another neighbouring connecting strip 55, so as to form the row 50 of connecting strips 55.

[0146] The manufacture of the tank according to the invention requires a limited number of welds. In addition, the flexibility of the tank walls necessary for their mechanical resistance during thermal contractions and expansions is preserved.

[0147] In the embodiment shown, the value of the angle between the load-bearing walls 1 and 2 is 90°. Other angle values ​​are also possible, for example 135°.

[0148] In the described embodiment, the primary stage of each tank wall, comprising the primary insulating barrier, the primary waterproof membrane and the structural elements for fixing them to the corresponding corner beam, is here identical to the secondary stage of each tank wall comprising the secondary insulating barrier, the secondary waterproof membrane and the structural elements for fixing them to the corresponding corner beam.

[0149] Alternatively, it may be envisaged that only the primary or secondary stage of the tank wall has the characteristics described below, and that the other stage has different characteristics, for example, in accordance with the prior art. The primary waterproof membrane and the primary insulating barrier are optional. The tank wall may comprise only one waterproof membrane and one insulating barrier.

[0150] As a further alternative, it may be envisaged that the waterproof membrane of the primary or secondary stage having the preceding characteristics comprises a waterproof membrane having corrugations, with raised longitudinal edges.

[0151] We will not describe in more detail the second wall of the tank of the example shown in [Fig.1], the structure of which is already known.

[0152] With reference to [Fig. 7], a cutaway view of an LNG carrier 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the vessel. The wall of the tank 71 comprises a primary watertight barrier intended to be in contact with the LNG contained in the tank, a secondary watertight barrier arranged between the primary watertight barrier and the double hull 72 of the vessel, and two insulating barriers arranged respectively between the primary watertight barrier and the secondary watertight barrier and between the secondary watertight barrier and the double hull 72.

[0153] In a manner known per se, loading / unloading pipelines 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a marine or port terminal or to an LNG bunker ship to transfer an LNG cargo to or from the tank 71.

[0154] Figure 7 shows an example of a marine terminal comprising a loading and unloading berth 75, a subsea pipeline 76 and an onshore facility 77. The loading and unloading berth 75 is a fixed offshore facility comprising a movable arm 74 and a tower 78 which supports the movable arm 74. The movable arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipelines 73. The steerable movable arm 74 is suitable for all LNG carrier sizes. An unshown connecting pipeline extends inside tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore facility 77. This facility includes liquefied gas storage tanks 80 and connecting pipelines 81 linked by the subsea pipeline 76 to the loading or unloading station 75.The subsea pipeline 76 allows the transfer of liquefied gas between the loading or unloading station 75 and the onshore facility 77 over a long distance, for example 5 km, which allows the LNG carrier 70 to be kept a long distance from the coast during loading and unloading operations.

[0155] To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the land installation 77 and / or pumps equipping the loading and unloading station 75 are used.

[0156] Although the invention has been described in connection with several particular embodiments, it is clearly evident that it is by no means limited to them and that it includes all technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[0157] The invention applies to ship tanks 71 and also to land-based reservoirs and port structures.

[0158] The use of the verb "comprise", "comprendre" or "include" and its conjugated forms does not exclude the presence of other elements or steps than those stated in a claim.

[0159] In the claims, any reference sign in parentheses shall not be interpreted as a limitation of the claim.

Claims

1. Demands A watertight and thermally insulating tank, integrated into a load-bearing structure comprising a first load-bearing wall (5) and a second load-bearing wall (25) joining the first load-bearing wall (5) at an edge (101) of the load-bearing structure, the tank comprising a first tank wall (1) fixed to the first load-bearing wall (5) and a second tank wall (2) fixed to the second load-bearing wall (25), in which at least the first tank wall (1) comprises at least one watertight membrane (7, 9) and an insulating barrier (6, 8) arranged between the watertight membrane (9) and the first load-bearing wall (5), in which the watertight membrane (7, 9) comprises a plurality of strakes (15) extending in a longitudinal direction perpendicular or oblique to the edge (101), a strake (15) comprising a flat portion (15B) resting on an internal surface of the insulating barrier (6,8) and two raised edges (15A) extending along the longitudinal direction and projecting inwards from the flat portion (15B) of the strake (15), the strakes (15) being juxtaposed in a transverse direction perpendicular to the longitudinal direction and welded together watertight at said raised edges (15A) to form expansion bellows (S), the watertight membrane (7, 9) comprising a metal corner beam (17) arranged parallel to the edge (101) of the supporting structure and anchored to the first and second supporting walls (5, 25), the corner beam (17) comprising a first lateral flange (18A, 18B) parallel to the first supporting wall (5) and a second lateral flange (19A, 19B) parallel to the second supporting wall (25), the two lateral flanges being joined to each other at the level of a sealed bond zone, in which at least one of the first and second lateral wings (18A, 18B, 19A,19B) of the corner beam is flat and extends parallel to the edge (101) and at a distance from a longitudinal end (15C) of the strakes (15), the watertight membrane (7, 9) further comprising a connecting strip (55, 50) adapted to watertightly connect the longitudinal end (15C) of at least one strake (15) to said at least one of the first and second lateral flanges (18A, 18B, 19A, 19B) of the corner beam, in which said connecting strip (50, 55) comprises at least one corrugation (51) covering said expansion bellows (S) of said at least one strake and at least one flat portion (52) applied against the flat portion (15B) of said at least one strake (15) and against said at least one of the first and second lateral flanges (18A, 18B, 19A, 19B) of the corner beam.

2. A sealed and thermally insulating tank according to claim 1, wherein said at least one corrugation (51) of the connecting strip (50, 55) has a first portion of corrugation (51A) whose height relative to the flat parts (52) of the connecting strip (50, 55) is uniform, the first portion of corrugation (51A) being located on the side of the strakes (15), and a second portion of corrugation (51B) extending the first portion of corrugation (51A) and whose height relative to the flat parts (52) of the connecting strip (50, 55) decreases in the direction of said flat parts (52) by sealing said corrugation (51).

3. A watertight and thermally insulating tank according to any one of the preceding claims, wherein the connecting strip (55) is in the form of an elongated plate along a principal direction (DP) parallel to the edge, said at least one corrugation being formed by stamping or folding said elongated plate, and wherein said at least one corrugation (51) extends along the longitudinal direction of the strakes, from an external principal edge (54A) of the elongated plate located on the side of the strakes (15).

4. A sealed and thermally insulating tank according to claim 3, wherein said at least one corrugation (51) extends to an internal principal edge (53A) of the elongated plate opposite the external principal edge (54A).

5. A watertight and thermally insulating tank according to any one of claims 1 to 4, wherein the connecting strip (50, 55) has at least two corrugations (51), preferably three corrugations.

6. A watertight and thermally insulating tank according to any one of claims 1 to 5, wherein the watertight membrane (9) comprises a row (50) of connecting strips (55), each connecting strip (55) comprising at least one corrugation (51) covering each of said expansion bellows (S) and at least one flat portion (52), the connecting strips (55) being juxtaposed along the direction of the edge (101) and being clinched welded to each other.

7. Watertight and thermally insulating tank according to any one of claims 1 to 5, in which the connecting strip (55) is hermetically welded to the longitudinal end (15C) of the strakes (15) and to said at least one of the first and second lateral wings (18A, 18B, 19A, 19B) of the beam.

8. A sealed and thermally insulating tank according to any one of the preceding claims, wherein the insulating barrier (6, 8) of the first tank wall (1) is made up of parallelepiped-shaped heat-insulating boxes (10) which are juxtaposed in a regular pattern.

9. A sealed and thermally insulating tank according to claim 8, wherein the first tank wall (1) further comprises anchoring members (20) which anchor the heat-insulating boxes to the first load-bearing wall (5), each anchoring member (20) comprising a base fixed to the first load-bearing wall and a coupler retained by the base and extending through the thickness of the insulating barrier and through the connecting strip (55).

10. Vessel (70) for the transport of a cold liquid product, the vessel comprising a double hull (72) and a watertight and thermally insulating tank according to any one of claims 1 to 9 disposed in the double hull.

11. Transfer system for a cold liquid product, the system comprising a vessel (70) according to claim 10, insulated pipes (73, 79, 76, 81) arranged to connect the vessel's tank (71) to a floating or land-based storage facility (77) and a pump to drive a flow of cold liquid product through the insulated pipes from or to the floating or land-based storage facility to or from the vessel's tank.

12. A method of loading or unloading a ship (70) according to claim 10, wherein a cold liquid product is conveyed through insulated pipes (73, 79, 76, 81) from or to a floating or land-based storage facility (77) to or from the ship's tank.

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