FR3025122A1 - ANGLE PIECE AND FOLDING DEVICE AND METHOD FOR FORMING CORRUGATION IN AN ANGLE PIECE - Google Patents

Abstract

The invention relates to a corner piece and a bending device and method for forming a corner piece for the construction of a waterproofing membrane. the corner piece (1) has first and second flanges (2, 3) inclined with respect to each other and joining at an edge, said corner piece (1) having a corrugation (8) extending longitudinally from one end to the other of the corner piece (1) so as to allow deformation of the corner piece in a transverse direction, parallel to the edge (4) ; the corrugation (8) having a first end portion (8a), a second end portion (8b) and a central portion (8c) extending between the first and second end portions (8b, 8c), as an extension of these; the first and second end portions (8a, 8c) of the corrugation (8) protruding outwardly from the corner piece (1) and the central portion (8a) projecting towards the interior of the piece angle (1).

Description

Technical Field The invention relates to a corner piece for the construction of a sealing membrane of a fluid storage tank. The invention also relates to a folding device and method for forming a corrugation in a corner piece. The invention relates in particular to the field of tanks, waterproof and thermally insulating, with membranes, for the storage and / or transport of fluid, such as a cryogenic fluid. BACKGROUND ART In the state of the art, corrugated metal membranes are known for forming sealing barriers for liquefied natural gas storage tanks. The sealing membrane consists of a plurality of metal plates having a series of perpendicular corrugations allowing it to deform under the effect of thermal and mechanical stresses generated by the fluid stored in the tank. In FR 2 996 520, there is described a metal membrane, constituting a secondary sealing barrier, comprising a plurality of metal plates having corrugations projecting outwardly of the vessel. The secondary sealing barrier is supported by a secondary thermal insulation barrier which is composed of a plurality of insulation blocks held against the bearing structure of the vessel. The insulation blocks of the secondary thermal insulation barrier are separated by interstices within which are inserted the corrugations of the metal plates of the secondary sealing barrier.

At the junction between two walls of the metal membrane, the metal membrane has corner pieces to ensure continuity of sealing at the corner area between the two walls. Summary An idea underlying the invention is to provide a corner piece that is flexible in order to be deformed under the effect of thermal and mechanical stresses generated by the liquefied natural gas stored in the tank. An idea underlying the invention is also to provide a device and a folding method for forming a corrugation in a corner piece. According to one embodiment, the invention provides a folding device for forming a corrugation in a corner piece having first and second plane flanges inclined with respect to each other and joining together. at an edge, the corrugation to be formed being intended to extend in a longitudinal direction intersecting at the edge of the other end of the corner piece so as to allow deformation of the corner piece in a transverse direction, parallel to the edge; the corrugation to be formed having a first end portion and a second end portion disposed respectively on the first flange and the second flange on either side of the edge and protruding outwardly of the corner piece and a central portion overlapping the edge and protruding inwardly of the corner piece, said central portion extending between the first and second end portions, in the extension of said first and second end portions, the folding device comprising: - a lower frame; two lower die elements carried by the lower frame and each comprising a bearing surface, the two bearing surfaces being respectively intended to receive an outer surface of the one and the other of the wings of the piece 20 of angle and being inclined relative to each other about a horizontal edge axis corresponding to the edge of the corner piece when the wings of the corner piece are received against the bearing surfaces the two lower die members each having a groove corresponding respectively to the shape of the one and the other of the first and second end portions of the corrugation; Two upper counter-matrices which are respectively associated with one and the other of the two lower matrix elements and arranged vis-à-vis the associated lower matrix element, each upper counter-matrix having a surface clamping parallel to the bearing surface of the associated lower die member and a punch having a shape complementary to the groove 30 of the associated lower die member; each of the two upper counter-matrices being movable orthogonally to the bearing surface of the associated lower matrix element between a rest position and a folding position in which the punch of the upper counter-matrix is engaged inside the groove of the associated lower die member to form the first and second end portions of the corrugation; - A movable upper frame, in a vertical direction secant to the edge axis, relative to the lower frame between a rest position and a folding position; An upper die element disposed between the upper counter-matrices carried by the upper frame, said upper die member having a recess having a shape corresponding to the shape of the central portion of the corrugation; and a lower punch disposed between the two lower die members, facing the upper die member, and having a shape complementary to the fingerprint of the upper die member, the lower punch being movably mounted on the lower frame, in said vertical direction secant to the edge axis, between a low rest position and a high folding position, wherein, when the upper frame is in its folding position, the lower punch is engaged within the imprint of the upper die member so as to form the central portion of the corrugation. Thus, such a folding device can form, in a corner piece, in a single press stroke, a corrugation having end portions protruding outwardly and a central portion protruding inwardly of the piece 20 'angle. A corner piece having a corrugation thus produced has a flexibility to deform under the effect of thermal and mechanical stresses and is particularly suitable for connecting metal plates of a sealing membrane of a vessel having corrugations 25 protruding outwardly of the vessel. According to embodiments, such a folding device may comprise one or more of the following characteristics: the vertical direction secant to the edge axis corresponds to the bisector of the angle formed by the two bearing surfaces. The upper counter-matrices are brought back remotely from the associated lower matrix element, towards their rest position by a return member; and the upper frame is able to bear against the upper counter-matrices 3025122 4 during its stroke between its rest position and its folding position so that the movement of the upper frame from its rest position to its folding position causes the upper countermatrices to move from their rest position to their folding position. Such an arrangement makes it possible to simply exert bending forces in two distinct directions respectively orthogonal to one and the other of the wings of the corner piece. - The upper counter-matrices each comprise a roller adapted to form a support of the upper frame during its stroke between its rest position and its folding position. The upper counter-matrices are each slidably mounted on the associated lower die member via guide tubes, carried by the lower die members, and sliding in bores in the upper countermatrices. the folding device comprises a plurality of return members recalling each of the upper counter-matrices in the direction of its rest position, the return members being compression springs or gas jacks exerting a return force between the lower matrix element and the associated upper counter matrix. - The folding device comprises a mechanism for actuating the lower punch 20 adapted to automatically move the lower punch to its upper folding position when the upper frame moves down towards its folded position. Thus, such a folding device makes it possible to dispense with an independent actuator for actuating the lower punch and requiring perfect synchronization with the movement of the upper countermatrices. The actuating mechanism of the lower punch comprises two levers which are each mounted articulated on the lower frame and each comprise: a first end provided with a bearing surface, extending inside the groove of the one of the lower die members adapted to cooperate, in use, with a portion of the corner piece to be folded to form the first or the second end portion of the corrugation such that the lever pivots when the upper counter-matrix vis-à-vis moves towards its folding position; and a second end cooperating with the lower punch to move the lower punch to its upper folding position when, due to a movement of the upper counter die to its folding position, the lever pivots. The upper die member is mounted vertically movable on the upper frame, the upper die member being biased away from the upper frame by a biasing member. the upper die element comprises, on either side of its fingerprint, a wedge-shaped portion complementary to the shape of the corner piece, said wedge-shaped portion being intended to bear against the edge and against the inner surfaces of the wings of the corner piece when the upper frame is in the folding position. - The lower punch comprises a central portion having a cross section of semi-elliptical or triangular shape. The central part of the lower punch has, along the longitudinal axis of the corrugation to be formed, a concavity. - The lower punch comprises two knives arranged longitudinally on either side of the central portion and each having at least one concavity, along the longitudinal axis of the corrugation to be formed. The imprint of the upper die element has a cross-section to the axis of the corrugation to be formed, of semi-elliptical or triangular shape. - The imprint of the upper die element has, along the longitudinal axis of the corrugation to form a convexity. the upper die element has two countershades arranged longitudinally on either side of the cavity and having along the longitudinal axis of the corrugation to form at least one convexity. According to one embodiment, the invention also provides a folding method for forming a corrugation in a corner piece having two flat wings inclined with respect to one another and joining at one edge by means of 30 of a aforementioned folding device, the corrugation to be formed being intended to extend in a longitudinal direction from one end to the other of the other of the corner piece so as to allow a deformation of the corner piece in a transverse direction parallel to the edge; the corrugation to be formed having a first end portion and a second end portion projecting outwardly of the corner piece and a central portion projecting inwardly of the corner piece, said central portion extending between the first and second end portions, 5 in the extension of said first and second end portions, the folding method comprising: positioning the corner piece so that the wings of the corner piece are respectively in abutment against the bearing surface of one and the other of the lower die elements; Moving the two countermatrices toward their folding position and moving the lower punch into its upper folding position to form the first and second end portions and the central portion of the corrugation. According to one embodiment, the invention also provides a corner piece for the construction of a sealing membrane of a storage tank of a fluid, the corner piece having a first and a second wings. planes inclined relative to each other and joining at an edge, said corner piece having a corrugation extending in a longitudinal direction secant to the edge, from one end to the other the corner piece so as to allow deformation of the corner piece in a transverse direction parallel to the edge; the corrugation comprising: a first end portion disposed on the first flange, extending perpendicular to the edge, from a first edge of the corner piece towards the edge; a second end portion, disposed on the second flange, extending perpendicular to the edge, from the second edge of the corner piece, opposite said first edge, towards the edge; - A central portion, overlapping the edge, extending between the first and the second end portions, in the extension of said first and second end portions; The first and second end portions of the corrugation protruding outwardly from the corner piece and the central portion projecting inwardly of the corner piece.

According to embodiments, such a corner piece may comprise one or more of the following characteristics: the central portion of the corrugation has a semi-elliptic or triangular profile having a height which is increasing in the longitudinal direction of 5 the undulation of each of the ends of the central portion to a central section of the central portion, according to a bisecting plane at the angle formed between the first and second wings. the central portion of the corrugation is partially bordered by undulations protruding outwards from the corner piece, disposed on either side of the central portion and whose depth is decreasing in the direction of the 'fish bone. the extreme portions of the corrugation have a semi-elliptical or triangular profile. - The semi-elliptical or triangular profile of the end portions of the corrugation has a constant depth. The middle section of the central portion of the corrugation has a height equal to the depth of the end portions of the corrugation. - The geometric configuration of the corner piece is developable in plan in the form of a rectangular piece. According to one embodiment, the invention also provides a sealed and thermally insulating fluid storage tank including a secondary thermal insulation barrier retained to a supporting structure, a secondary waterproofing membrane supported by the barrier of secondary thermal insulation, a primary thermal insulation barrier and a primary waterproofing membrane supported by the primary thermal insulation barrier and intended to be in contact with the fluid contained in the tank, in which: the barrier of secondary thermal insulation comprises rectangular parallelepiped-shaped insulation blocks, juxtaposed in parallel rows and separated from each other by interstices; the secondary waterproofing membrane comprises a plurality of metal sheets comprising at least two orthogonal corrugations parallel to the sides of the thermal insulation blocks and inserted into the interstices formed between the insulation blocks or in slots provided in the blocks of insulation. insulation and a plurality of aforementioned corner pieces connecting the metal sheets of a first and second adjacent walls, at the angle formed between said first and second walls. Such a tank may be part of an onshore storage facility, for example to store LNG or be installed in a floating structure, coastal or in deep water, including a LNG tank, a floating storage and regasification unit (FSRU ), a floating production and remote storage unit (FPSO) and others. According to one embodiment, the invention relates to a vessel for the transport of a fluid comprising a double hull and a said tank disposed in the double hull. According to one embodiment, the invention also provides a method of loading or unloading such a vessel, wherein a fluid is conveyed through isolated pipes from or to a floating or land storage facility to or from the vessel. of the ship. According to one embodiment, the invention also provides a transfer system for a fluid, the system comprising the abovementioned vessel, insulated pipes arranged to connect the vessel installed in the hull of the vessel to a floating or ground storage facility. and a pump for driving a fluid through the insulated pipelines from or to the floating or land storage facility to or from the vessel vessel. BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent from the following description of several particular embodiments of the invention given only in connection with illustrative and non-limiting, with reference to the accompanying drawings. - Figure 1 is a perspective view of a corner piece for the construction of a sealing membrane of a fluid storage tank. FIG. 2 is a detailed perspective view of the outer surface of the corner piece of FIG. 1 at its edge. - Figure 3 is a detailed view, in perspective, of the inner surface of the corner piece of Figure 1, at its edge. FIG. 4 is a sectional view of FIG. 1 along a plane passing through the longitudinal axis of the corrugation. FIG. 5 is a three-quarter view of the corner piece of FIG. 1 cut along a longitudinal plane passing through the axis of the corrugation; FIG. 6 is a three-quarter view of the piece of FIG. angle of Figure 1 cut along a transverse plane passing through the edge of the corner piece. - Figures 7, 8 and 9 illustrate the folding device respectively in a high rest position, an intermediate position of contact with the corner piece and a bending position, end of stroke. FIGS. 10, 14 and 18 are front views of the folding device respectively in its high rest position, in its intermediate position of contact with the corner piece and in its folding position, at the end of the stroke. - Figures 11, 15 and 19 are side views of the folding device respectively in its upper rest position, in its intermediate position 15 of contact with the corner piece and in its folding position, at the end of the race - The FIGS. 12, 16 and 20 are cross-sectional views respectively along planes XII-XII, XVI-XVI and XX-XX of FIGS. 11, 15 and 19. FIGS. 13, 17 and 21 are cross-sectional views respectively according to FIGS. XIII-XIII, XVII-XVII and XXI-XXI of FIGS. 10, 14 and 18. FIG. 22 is a detailed view of three quarter-lowers of the folding device in section along the plane XII-XII of FIG. 11. FIG. 23 is a three quarter top detail view of the folding device in section along the plane XII-XII of FIG. 11. FIG. 24 is a cutaway schematic representation of a tank of a LNG carrier and a FIG. loading / unloading terminal of this tank. DETAILED DESCRIPTION OF EMBODIMENTS FIGS. 1 to 6 illustrate an angle piece 1 for the construction of a sealing membrane of a fluid storage vessel. Such a corner piece 1 is intended to connect two adjacent walls of a sealing membrane at the angle formed between the two walls.

The corner piece 1 is obtained by folding a sheet metal. The metal sheet may in particular be made of stainless steel, aluminum, Invar ®: that is to say an alloy of iron and nickel whose expansion coefficient is typically between 1.2.10-6 and 2.10-6 K-1, or in a high manganese iron alloy whose expansion coefficient is of the order of 7.10-6 K-1. However, other metals or alloys are also possible. For example, the metal sheet 1 has a thickness of about 0.7 mm. Other thicknesses are also conceivable, given that a thickening of the metal sheet leads to an increase in its cost and generally increases the rigidity of the corrugations. The corner piece 1 comprises a first and a second plane wings 2, 3 inclined relative to each other and joining at an edge 4. The projecting angle formed between the two wings is of 135 ° order in the embodiment shown. However, the angle may be different, of the order of 90 °, for example, when the two adjacent walls to be connected are perpendicular, or more generally between 90 ° inclusive and 180 ° excluded. Each wing 2, 3 has a rectangular parallelepipedal shape and thus comprises two opposite parallel lateral edges 5, 6 and an end edge 7 opposite to the other wing 2, 3. The corner piece 1 comprises a corrugation 8 conferring flexibility to deform under the effect of thermal and mechanical stresses generated by the liquefied natural gas stored in the tank. The corrugation 8 extends in a longitudinal direction, secant at the edge 4, from one end to the other of the corner piece 1. The corrugation 8 thus extends parallel to the opposite side edges 5, The corrugation 8 thus allows the corner piece to deform in a transverse direction, parallel to the edge 4. The corrugation 8 can be divided into three portions, a first end portion 8a, formed in the first wing 2, a second end portion 8b, formed in the second flange 3 and a central portion 8c extending between the first and the second end portions 8a, 8b in the extension thereof.

The first end portion 8a extends from the free edge 7 of the first flange 2 towards the edge 4. Symmetrically, the second end portion 8b extends from the free edge 7 of the second end portion 8a. 3, in the direction of the edge 4. The first and second end portions 8a, 8b of the corrugation project outwardly from the corner piece 1, that is to say towards the outside the projecting angle formed between the two wings 2, 3. In the embodiment shown, the end portions 8a, 8b have a triangular profile. However, according to an alternative embodiment, the end portions 8a, 8b have a semi-elliptical profile. The depth of the extreme portions 8a, 8b is constant over their entire length. For example, the end portions have a depth of between 10 and 60 mm depending on the intended applications. The central portion 8c of the corrugation 8 extends between the two wings 2, 3, in the extension of the end portions 8a, 8b and overlaps the edge 4. The central portion 8c protrudes towards the interior of the room angle 1, ie towards the inside of the projecting angle formed between the two wings 2, 3. Thus, the central portion 8c is intended to project towards the inside of the tank, when the piece angle 1 is in position, within the tank. The central portion 8 has a substantially triangular shape profile, as shown in Figure 6. However, according to another embodiment not shown, the central portion 8 has a semi-elliptical profile. The height of the central portion 8c of the corrugation is increasing by going from each of its ends towards its median section. Here, the term "middle section" of the central portion, the section of the central portion along a bisector plane passing through the edge 4 and intersecting the angle formed between the two wings 2, 3 in two equal angles. The height of the central portion 8c at its central section is substantially equal to the depth of the end portions 8a, 8b. It is also observed, for example in FIG. 3, that the central portion 8c, projecting inwards, is bordered on either side of the longitudinal axis of the corrugation 8 by corrugations 9a, 9b , outwardly projecting from the corner piece 1. The fold lines of the undulations 9a, 9b extend on either side of the central portion 8c from the ridge of the end portions 8a, 8b. The depth of the corrugations 9a, 9b decreases towards the edge 4 so that the corrugations 9a, 9b are interrupted before the axis of the edge 4.

Such a configuration of the end portions 8a, 8b, of the central portion 8c and of the corrugations 9a, 9b makes it possible to obtain a geometrical configuration of the corner piece 1 which can be developed in plan in the form of a rectangular piece. In other words, the configuration of the corner piece 1 in the corrugation zone 8 is such that the aforesaid forms do not cause any change in the material length of the metal sheet and therefore also not modifying the thickness of the metal sheet. Moreover, it can be observed, in particular in FIGS. 3 or 4, that the central portion 8c of the corrugation 8 has a series of waves transverse to the longitudinal direction of the corrugation 8. Figure 4 that the ridge line 10 of the central ripple has a series of waves. Such an arrangement makes it possible to impart flexibility to the corner piece 1 in the longitudinal direction of the corrugation 8 so as to allow a slight pivoting of the wings 2, 3 relative to each other around the edge 4 and thus allow a slight variation of the angle formed between the two wings 2, 3. In a first application, the corner piece 1, as described above, is intended for the construction of a tank of storage as described in W014057221. The general structure of such a vessel is well known and has a polyhedral shape. The wall of the tank comprises, from the outside to the inside of the tank, a supporting structure, a secondary thermal insulation barrier comprising insulation blocks held against the supporting structure and anchored to it by bodies secondary containment membrane, a secondary sealing membrane carried by the insulation blocks of the secondary thermal insulation barrier, a primary thermal insulation barrier comprising insulation blocks, anchored to the secondary waterproofing membrane by primary retaining members and a primary sealing membrane carried by the insulation blocks of the primary thermal insulation barrier and intended to be in contact with the cryogenic fluid contained in the tank.

The supporting structure may in particular be a self-supporting metal sheet or, more generally, any type of rigid partition having appropriate mechanical properties. The supporting structure may in particular be formed by the hull or the double hull of a ship. The carrying structure comprises a plurality of walls defining the general shape of the tank.

The secondary sealing barrier has a plurality of metal plates. Each metal plate has at least two orthogonal corrugations protruding outwardly of the vessel. In addition, the insulation blocks of the secondary thermal insulation barrier have a rectangular parallelepiped shape and are juxtaposed in parallel rows. According to one embodiment, the insulation blocks of the secondary thermal insulation barrier separated from each other by interstices inside which are inserted the corrugations of the metal plates. According to another embodiment, the insulation blocks of the secondary thermal insulation barrier have, on their internal surface, slots inside which the corrugations of the metal plates are inserted. At an angle zone between two adjacent walls, corner pieces 1, as described above, are arranged such that their corrugation 8 is in the extension of the corrugations of the adjacent metal plates of FIG. one and the other of the walls. The corner pieces 1 are connected to the adjacent metal plates, by welding, to ensure a continuity of sealing at the corner area. In this first application, the end portions 8a, 8b of the corrugation 8 of the corner pieces 1 protrude outwardly of the vessel while the central portion 8c protrudes into the vessel. For such an application, the end portions 8a, 8b of the corrugation typically have a depth of the order of 10 to 25 mm. According to a second application, the corner piece 1, as described above, is intended for the construction of specific areas of a primary sealing membrane of a storage tank, as described in the document FR2691520. or FR2984454, for example. Such a primary waterproofing membrane is known under the designation "Mark III". This primary waterproofing membrane has a plurality of corrugated metal plates welded to one another. Each metal plate has at least two orthogonal corrugations which project from the side of the internal face of the metal plate intended to be brought into contact with the fluid contained in the tank. In this application, the corner piece 1 can be used in a zone of interruption of the primary waterproofing membrane at a dome formed in a wall of the tank. Such domes are referred to as "liquid dome" when they serve as a point of entry for equipment for filling the tank and as a "gas dome" when used for the extraction of natural gas in the vapor phase. Such corner pieces can also be used in an area of interruption of the sealing membrane at a sump structure for housing a pump unloading the tank. In this second application, the projecting angle of the corner piece 1 is directed towards the outside of the tank. Thus, the end portions 8a, 8b of the corrugation 58 of the corner pieces 1 protrude inwardly of the vessel while the central portion 8c protrudes outwardly of the vessel. For such an application, the end portions 8a, 8b of the corrugation typically have a depth of the order of 40 to 60 mm and the projecting angle formed between the two wings of the corner piece is of the order of 90 °.

A folding device and method for forming the corrugation 8 in a corner piece 1, as described above, will now be described in connection with FIGS. 7 to 23. By convention, the "longitudinal" orientation Of the folding device is directed in the longitudinal direction of the corrugation to be formed and the "transverse" orientation is directed transversely to the longitudinal direction of the corrugation to be formed. In a first step, a metal sheet is folded beforehand so as to form the two plane wings 2, 3 inclined with respect to one another. Subsequently, the corrugation 8 is formed in the corner piece by means of the folding device 11 as described below.

The folding device 11 comprises a lower frame 12 and an upper frame 13 mounted vertically movable relative to the lower frame 12. The upper frame 13 is movable between a high rest position and a bending position of the sheet in which it it is deformed to form the corrugation 8. The upper frame 13 is thus able to exert on the corner piece 1 a pressure allowing the folding 25 of the metal sheet and the formation of the corrugation 8. The upper frame 13 is shown in its rest position in Figures 7 and 10 to 13 and in its folded position in Figures 9 and 18 to 21. The upper frame 13 here carries stopper fingers 49 bearing against the lower frame 12 so The stop fingers 49 are shown in alignment with the edge 4, but may be positioned differently. The upper frame 13 is also shown in an intermediate position of contact with the corner piece 1, just before the formation of the corrugation 8 begins, in FIGS. 8 and 14 to 17.

For example, as shown in FIG. 10, the lower frame 12 supports two lower die members 14, 15 disposed on either side of a median transverse plane. The lower die members 14, 15 each have a bearing surface 17 for receiving the outer surface of the wings 2, 5 3 of the corner piece 1. The bearing surfaces 17 are inclined about an axis d horizontal edge which is coincident with the edge 4 of the corner piece 1 when the wings 2, 3 of the corner piece 1 are received against the bearing surfaces 17. The inclination of the bearing surfaces 17 is oriented such that the inside of the corner piece 1 is directed upwards, towards the upper frame 13, when the corner piece 1 10 is positioned against the lower die elements 14, 15. The bearing surfaces are symmetrical with respect to a median vertical transverse plane. Furthermore, as shown in FIG. 11, the lower matrix elements 14, 15 comprise a groove 18 forming an imprint corresponding to the shape of the corrugation 8 to be formed at its end portions 8a, 8b. The grooves 18 extend in the longitudinal direction and have a triangular section, in the embodiment shown, or semi-elliptical, in an embodiment not shown. Returning to FIG. 10, it can be observed that the folding device 11 also comprises two upper counter-matrices 19, 20 which are each associated with a lower die element 14, 15 and arranged opposite the this one. The upper counter-matrices 19, 20 each comprise a clamping surface 21 parallel to the bearing surface 17 of the associated lower die element 14, 15. The clamping surfaces 21 are intended to press the wings 2, 3 of the corner piece 1 against the bearing surface 17 of the lower die member 14, 15 vis-a-vis when the upper countermatrices 19, 20 are in a folding position. In addition, the upper counter-matrices 19, 20 each comprise a punch 22, illustrated in FIG. 11, having a shape complementary to that of the groove 18 of the associated lower die element 14, 15. The two upper countermatrices 19, 20 are each movably mounted on the associated lower die member 14, 15 in a direction orthogonal to the bearing surface 17 of said die member 14, 15. The upper countermatrices 19 , 20 are thus movable between a high rest position, illustrated in Figures 10, 11 and 12, and a folding position, illustrated in Figures 18, 19 and 20, wherein their punch 22 is engaged within the groove 18 of the lower die member 14, 15 facing each other, so as to press the metal sheet and form the end portions 8a, 8b of the corrugation 8. Each upper counter-die 19, 20 is slidably mounted on its respective lower die member 14, 15 via a guide device, particularly illustrated in FIGS. 10 and 11, having a plurality of guide tubes 23 integral with the lower die member 14, 15. The counter matrices sup Rails 19, 20 have bores which are each engaged around one of said guide tubes 23 to guide the movement of the upper countermatrices 19, 20 relative to the associated lower die member 14, 15. By way of example, in the embodiment shown, each lower die member 14, 15 has four guide tubes 23 disposed near the four corners of the lower die member 14, 15. In addition, Compression 24 or gas cylinders are arranged between each lower die member 14, 15 and the associated upstanding die 19, 20. The compression springs 24 comprise a first end housed in a blind hole, not shown, formed in a lower die member 14, 15 and a second end housed in a blind hole, not shown, provided in the upper counter-die 19, 20 vis-à-vis. The compression springs 24 or the gas cylinders thus exert on the upper countermatrices 19, 20 a return force which tends to return them to their rest position. As shown in FIG. 10, each lower counter-matrix 19, 20 carries a roller 25 mounted to rotate about a horizontal axis 26 extending in the transverse direction. The axis of the roller 26 is carried by a roller holder 27 fixed on the lower counter-die 19, 20 and having two lateral wings which support the axis of the roller 26 and between which is disposed the roller 25. The roller 25 is able to form a support of the upper frame 13 during its stroke between its rest position and its folding position, as shown in Figures 14 and 16. Thus, during its stroke between its rest position and its position of The top frame 13 bears against the rollers 25 so as to move the upper countermatrices 19, 20 from their rest position to their folding position. Thus, the presence of the rollers 25 makes it possible to limit the frictional forces exerted between the upper frame 13 and the upper countermatrices 30, 19, 20 when the upper frame 13 bears on the upper counter-matrices 19, 20 for move them to their folding position. Furthermore, with reference to FIGS. 12 and 13, it can be seen that the folding device 11 also comprises a lower punch 28 carried by the lower frame 12 and disposed between the two lower die elements 14, 15, and one upper die member 29 carried by the upper frame 13. The lower punch 28 and the upper die member 29 allow the formation of the central portion 8c of the corrugation. To do this, as illustrated in FIG. 13, the upper die element 29 has an impression 30 corresponding to the shape of the corrugation 8 in its central portion 8c and the lower punch 28 has a shape 31 complementary to that of the impression 30 of the upper die member 29. As shown in Fig. 13, the upper die member 29 is mounted vertically movable on the upper frame 13 via a guiding device. The guide device comprises two vertical guide tubes 32 fixed to the upper frame 13, and the upper die member 29 has bores which are engaged around said guide tubes 32 to guide the movement of the upper die member. In addition, retaining plates 33, having a larger diameter than the bores of the upper die member 29, are attached to the lower end of the guide tubes 32 and thus retain the Upper die member 29 on upper frame 13. In addition, compression springs 34 exert an elastic force between upper frame 13 and upper die member 29. To do this, compression springs 34 comprise first end housed in a blind hole, formed in the upper frame 13 and a second end housed in a blind hole, formed in the die element As shown in FIG. 10, the upper die member 29 has, on either side of its fingerprint 30, wedge-shaped portions 30 having a shape complementary to the shape of the blank. The corner-shaped portions 35 have an angle substantially identical to the angle of the corner piece 1 and have two inclined surfaces 36, 37, one of which 36 is intended to come against an inner surface of the corner. one of the wings 2, 3 of the corner piece 3025122 and the other of which is intended to come against an inner surface of the other of the wings 2, 3, when the upper frame 13 moves towards its folding position . Thus, when the upper frame 13 moves towards its folding position, the upper die member 10 comes to press the corner piece 1 at the edge 4 and 5 of the inner surfaces of the wings 2, 3 (see FIGS. and 21). The lower punch 28 is movably mounted on the lower frame 12 between a low rest position, shown in Figures 10, 12, 13, 14, 16 and 17 and an upper folding position, shown in Figures 18, 20 and 21. In order to move the lower punch 28 to its upper folding position, the folding device is equipped with an actuating mechanism, illustrated in Figures 12, 16 and 20, which is adapted to move the lower punch 28 towards the top, towards its upper folding position, when the upper frame 13 moves down towards its folding position. The actuating mechanism comprises two levers 38, 39. The levers 38, 39 are mounted articulated on the lower frame 12 about a transverse horizontal axis of rotation 40, 41. The levers 38, 39 each comprise a first end 42 passing through an opening in the lower die members 14, 15 and opening into the groove 18 of said lower die members 14, 15.

Thus, the first end 42 of each lever 38, 39 is intended to cooperate, in operation with a portion of the metal sheet to be folded by the punch 22 of the upper against-matrix 19, 20 vis-à-vis . Furthermore, the levers 38, 39 have a second end 43 cooperating with the lower punch 28 to move it. The first end 42 of the levers carries a contact piece 44 which is, on the one hand, mounted articulated on the first end 42 of the levers via a ball joint and, on the other hand, has a flat bearing sole intended to cooperate with the corner piece 1. Such an arrangement makes it possible to obtain a contact surface between the lever 38, 39 and the constant corner piece 1 during the pivoting of the levers 38, 39. Moreover, the second end 43 of the The levers 38, 39 are inserted inside a housing 45 of the lower punch 28. The housing 45 has an upper flange 46 so that when the levers 38, 39 pivot, they exert on the upper rim 46 a force tending to move the lower punch 28 upwards.

The levers 38, 39 are symmetrical with respect to each other, with respect to a transverse median plane. The levers 38, 39 therefore pivot in opposite directions of rotation which ensures a balancing of efforts. In operation, when the upper frame 13 moves from its high resting position to its folding position, the upper frame 13 will pass through an intermediate contact position, illustrated in FIG. 14, until the folding starts. . In this position, the upper frame 13 is supported on the upper counter-matrices 19, 20 which are themselves in contact with the wings 2, 3 of the corner piece 1. Moreover, the corner 35 of the element the upper die 29 10 plates the corner piece 1 at its angle. Subsequently, when the punches 22 of the upper counter-matrices 19, 20 engage inside the grooves 18 of lower die elements 14, 15, the punches 22 exert on the first ends 42 of the levers 38, 39 a force to rotate them so that the second ends 43 of the levers 38, 39 act on the lower punch 28 to move it to its upper folding position in which it engages inside the impression 30 of the upper die member 29. Thus, as the end portions 8a, 8b of the corrugation 8 are formed by pressing the upper countermatrices 19, 20 against the lower die members 14, 15 the lower punch 28 moves to its upper folding position and engages inside the cavity 30 of the upper die member 29 so as to form the central portion 8c of the corrugation 8. geometry of the footprint 30 of the upper die member 29 and the lower punch geometry 28 are described below, in connection with Figs. 22 and 23. The fingerprint 30, shown in Fig. 22, has a substantially shaped cross section. triangular or semi-elliptical. Furthermore, the impression 30 has, in section along a longitudinal plane, a slight convexity making it possible to form a wave transverse to the longitudinal direction of the corrugation 8, at the level of its central portion 8c. Furthermore, the upper die element 29 comprises, longitudinally, on either side of the footprint 30 of the counter-knives 47, blade-shaped, extending in the longitudinal direction and intended to bear against the wings 2, 3 of the corner piece 1. The counter-knives 47 also have a convexity directed downwards to form waves transverse to the longitudinal direction of the corrugation 8 at its central portion 8c . The lower punch 28, illustrated in FIG. 23, has a shape 31 complementary to the shape of the cavity 30 of the upper die element 29.

Thus, the lower punch 28 has, in a central part, a cross section of substantially triangular or semi-elliptical shape. Furthermore, the lower punch 28 has in section along a longitudinal plane a slight concavity. Longitudinally on either side of its central part, the lower punch 28 comprises knives 48, in the form of a blade, arranged opposite the counter-knives 47 and intended to deform the corner piece at the ends of its central portion 8c. The folding process will now be described in detail. In a first step, a metal sheet is previously bent to form a corner piece 1 having two flanges 2, 3 inclined relative to each other around a ridge 4. Thereafter, the piece the angle of incidence 1 thus produced is positioned against the lower die elements 14, 15. The projecting angle of the corner piece is directed towards the upper frame 13 so that the outer surfaces of the wings 2, 3 rest against the bearing surfaces 17 of the lower die elements 14, 15.

When the corner piece 1 has been correctly positioned, the upper frame 13 is moved downward from its rest position, illustrated in FIGS. 7 and 10 to 13. As it moves towards its end position, the upper frame 13 bears against the upper countermatrices 19, 20 (see FIGS. 14 and 16) to move it to their folding position and the wedge-shaped portions 35 of the upper die member 29 are pressed against the inner surface of the corner piece 1, in its corner area (see Figures 14 and 17). Subsequently, when the upper frame 13 descends to its end position, the punches 22 of the upper counter-matrices 19, 20 engage inside the grooves 18 of lower die elements 14, 15, in order to forming the end portions 8a, 8b of the corrugation 8 (see Figures 18, 19 and 21). When the punches 22 engage inside the grooves 18, the metal sheet exerts a force on the actuating levers 38, 39 of the lower punch 3025122 21 28 so that the latter moves towards its upper position. folding and engages inside the imprint 30 of the upper die member 29 so as to form the central portion 8c of the corrugation 8 (see Figure 20). Although the device and method of folding has been described in connection with a particular embodiment, it is obvious that they are not limited thereto. In particular, it is obvious that if the folding device illustrated in FIGS. 7 to 23 is intended to form a corrugation in a corner piece having an angle of the order of 135 °, it can be easily modified to form a corrugation in a corner piece having any other angle, and in particular 90 °.

Referring to FIG. 24, a cut-away view of a LNG tanker 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the tank 71 comprises a primary sealed barrier intended to be in contact with the LNG contained in the tank, a secondary sealed barrier arranged between the primary sealed barrier and the double hull of the ship, 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. In a manner known per se, loading / unloading pipes 73 arranged on the upper deck of the ship can be connected by means of connectors. appropriate to a marine or port terminal for transferring a cargo of LNG to or from the tank 71. Figure 24 shows an example of a marine terminal including a loading and unloading station 75, an underwater line 76 and an installation. 77. The loading and unloading station 75 is a fixed off-shore installation 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 pipes 73. The movable arm 74 can be adapted to all the jigs of LNG. A connection pipe (not shown) extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG tank 70 from or to the shore facility 77. This comprises liquefied gas storage tanks 80 and connecting lines 81 connected by the underwater line 76 to the loading or unloading station 75. The underwater line 76 3025122 22 allows the transfer of the liquefied gas between the loading station or unloading 75 and the onshore installation 77 over a large distance, for example 5 km, which makes it possible to keep the LNG ship 70 at a great distance from the coast during the loading and unloading operations.

In order to generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps equipping the shore installation 77 and / or pumps equipping the loading and unloading station 75 are used. Although the invention has been described in connection with several particular embodiments, it is quite obvious that it is in no way limited thereto and that it comprises all the technical equivalents of the means described as well as their combinations if these These are within the scope of the invention. The use of the verb "to include", "to understand" or "to include" and its conjugate forms does not exclude the presence of other elements or steps other than those set forth in a claim. The use of the indefinite article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps. In the claims, any reference sign in parentheses can not be interpreted as a limitation of the claim. 20

Claims (27)

REVENDICATIONS1. Folding device (11) for forming a corrugation (8) in a corner piece (1) having first and second plane flanges (2, 3) inclined with respect to each other and joining at an edge (4), the undulation (8) to be formed being intended to extend in a longitudinal direction secant to the edge (4) from one end to the other of the other the corner piece (1) so as to allow a deformation of the corner piece (1) in a transverse direction, parallel to the edge (4); the corrugation to be formed comprising a first end portion (8a) and a second end portion (8b) respectively disposed on the first flange (2) and on the second flange (3) on either side of the edge (4). ) and protruding outwardly of the corner piece (1) and a central portion (8c) overlapping the edge (4) and protruding inwardly of the corner piece (1), said central portion (1c) 8c) extending between the first and the second end portions (8a, 8b), in the extension of said first and second end portions (8a, 8b), the folding device (11) comprising: - a lower frame (12) ; - two lower die elements (14, 15) carried by the lower frame (12) and each having a bearing surface (17), the two bearing surfaces (17) being respectively intended to receive an outer surface of the one and the other of the wings (2, 3) of the corner piece (1) and being inclined relative to each other about a horizontal edge axis corresponding to the edge (4). ) of the corner piece (1) when the wings (2, 3) of the corner piece (1) are received against the bearing surfaces (17), the two lower die elements (14, 15) each having a groove (18) respectively corresponding to the shape of the one and the other of the first and second end portions (8a, 8b) of the corrugation (8); two upper counter-matrices (19, 20) which are respectively associated with one and the other of the two lower matrix elements (14, 15) and arranged opposite the associated lower matrix element , each upper counter-die (19, 20) having a clamping surface (21) parallel to the bearing surface (17) of the associated lower die member (14, 15) and a punch (22) having a complementary shape to the groove (18) of the associated lower die member (14, 15); each of the two upper counter-matrices (19, 20) being movable orthogonally to the bearing surface (17) of the associated lower matrix element (14, 15) between a rest position and a folding position in wherein the punch (22) of the upper counter-matrix (19, 20) is engaged within the groove (18) of the associated lower die member (14, 15) so as to form the first and the second extreme portions of the ripple; - an upper frame (13) movable, in a vertical direction secant to the edge axis, relative to the lower frame (12) between a rest position and a folding position; an upper die element (29) disposed between the upper counter-matrices (19, 20) carried by the upper frame (13), said upper die member (29) having a cavity (30) having a shape corresponding to the shape of the central portion (8c) of the corrugation (8); and - a lower punch (31) disposed between the two lower die members (14, 15), opposite the upper die member (29), and having a shape complementary to the fingerprint ( 30) of the upper die member (29), the lower punch (31) being movably mounted on the lower frame (12), in said vertical direction intersecting with the edge axis, between a low rest position and a high folding position, in which, when the upper frame (13) is in its folding position, the lower punch (31) is engaged within the cavity (30) of the upper die element (29) to form the central portion (8c) of the corrugation (8). 2. Device (11) for folding according to claim 1, wherein the vertical direction secant to the axis of edge corresponds to the bisector of the angle formed by the two bearing surfaces (17). 25 Folding device (11) according to claim 1 or 2, wherein: - the upper counter-matrices (19, 20) are remotely removed from the associated lower matrix element (14, 15) in the direction of their rest position by a return member (24); and the upper frame (13) is able to bear against the upper counter-matrices (19, 20) during its stroke between its rest position and its folding position so that the movement of the upper frame (13 ) from its resting position to its folding position causes the upper countermatrices (19, 20) to move from their rest position to their folding position. 4. Folding device (11) according to claim 3, wherein the upper counter-matrices (19, 20) each comprise a roller (25) adapted to form a support of the upper frame (13) during its race between its rest position and its folding position. Folding device (11) according to claim 3 or 4, wherein the upper counter-matrices (19, 20) are each slidably mounted on the associated lower matrix element (14, 15) via tubes guides (23), carried by the lower die members (14, 15) and slidable in bores in the upper countermatrices (19, 20). 6. Folding device (11) according to claim 5, comprising a plurality of return members each reminding each of the upper against-matrix (19, 20) towards its rest position, the return members being springs of 15 compression (24) or gas cylinders exerting a return force between the lower die member (14, 15) and its associated upper counter-die (19, 20). Folding device (11) according to any one of claims 1 to 6, comprising an actuating mechanism of the lower punch (28) able to automatically move the lower punch (28) to its upper folding position when the upper frame (13) moves down towards its folding position. 8. Folding device (11) according to claim 7, wherein the actuating mechanism of the lower punch comprises two levers (38, 39) which are each mounted articulated on the lower frame (12) and each comprise: - a first end (42) provided with a bearing surface, extending inside the groove (18) of one of the lower die members (14, 15) and adapted to cooperate, in use, with a portion of the corner piece (1) to be folded to form the first or the second end portion (8a, 8b) of the corrugation (8) so that the lever (38, 39) pivots when the counter-upper die (19, 20) vis-à-vis moves towards its folding position; and a second end (43) cooperating with the lower punch (28) so as to move the lower punch (28) to its upper folding position when, due to displacement of the upper counter-die (28); 19, 20) to its folding position, the lever (38, 39) pivots. Folding device (11) according to any one of claims 1 to 8, wherein the upper die element (29) is mounted vertically movable on the upper frame (13), the upper die element ( 29) being remotely recalled from the upper frame (13) by a return member (34). Folding device (11) according to any one of claims 1 to 9, wherein the upper die element (29) comprises on either side of the cavity (30), a portion in the form of corner (35) complementary to the shape of the corner piece (1), said wedge-shaped portion (35) being intended to bear against the edge (4) and against the inner surfaces of the wings (2). , 3) of the corner piece (4) when the upper frame (13) is in the folding position. The folding device (11) according to any one of claims 1 to 10, wherein the lower punch (28) has a central portion having a cross-section of semi-elliptical or triangular shape. 12. Folding device (11) according to claim 11, wherein the central portion of the lower punch (28) has, along the longitudinal axis of the corrugation to be formed, a concavity. Folding device (11) according to claim 11 or 12, wherein the lower punch (28) has two knives (48) arranged longitudinally on either side of the central part and each having at least one concavity, along the longitudinal axis of the corrugation (8) to be formed. The folding device (11) according to any one of claims 1 to 13, wherein the indentation (30) of the upper die member (29) has a cross-section to the corrugation axis. (8) to form, semi-elliptical or triangular shape. The folding device (11) according to claim 14, wherein the imprint (30) of the upper die member (29) has, along the longitudinal axis of the wave to form a convexity. 30 The folding device (11) according to claim 14 or 15, wherein the upper die member (29) has two counter knives (47) disposed longitudinally on either side of the fingerprint (30). ) and having along the longitudinal axis of the corrugation to form at least one convexity. 17. Folding method for forming a corrugation (8) in a corner piece (1) having two plane flanges (2, 3) inclined relative to each other and joining at one edge (4) by means of a folding device (11), the undulation (8) to be formed being intended to extend in a longitudinal direction secant to the edge (4) from one end to the other of the other of the corner piece (1) so as to allow a deformation of the corner piece (1) in a transverse direction, parallel to the edge (4); the corrugation to be formed comprising a first end portion (8a) and a second end portion (8b) respectively disposed on the first flange (2) and on the second flange (3) on either side of the edge ( 4) and protruding outwardly from the corner piece (1) and a central portion (8c) overlapping the edge (4) and protruding inwardly from the corner piece (1), said central portion (8c) extending between the first and the second end portions (8a, 8b), in the extension of said first and second end portions (8a, 8b), the folding device (11) comprising: - a lower frame ( 12); two lower die elements (14, 15) carried by the lower frame (12) and each having a bearing surface (17), the two bearing surfaces (17) being respectively intended to receive an outer surface of one and the other of the wings (2, 3) of the corner piece (1) and being inclined with respect to one another about a horizontal edge axis corresponding to the edge ( 4) of the corner piece (1) when the wings (2, 3) of the corner piece (1) are received against the bearing surfaces (17), the two lower die elements (14, 15 ) each having a groove (18) respectively corresponding to the shape of one and the other of the first and second end portions (8a, 8b) of the corrugation (8); two upper counter-matrices (19, 20) which are respectively associated with one and the other of the two lower matrix elements (14, 15) and arranged opposite the associated lower matrix element each upper counter-die 30 (19, 20) has a clamping surface (21) parallel to the bearing surface (17) of the associated lower die member (14, 15) and a punch (22) having a shape complementary to the groove (18) of the associated lower die member (14, 15); each of the two upper counter-matrices (19, 20) being movable orthogonally to the bearing surface (17) of the associated lower matrix element (14, 15) between a rest position and a folding position in wherein the punch (22) of the upper counter-matrix (19, 20) is engaged within the groove (18) of the associated lower die member (14, 15) so as to form the first and the second extreme portions of the ripple; - an upper frame (13) movable, in a vertical direction secant to the edge axis, relative to the lower frame (12) between a rest position and a folding position; an upper die element (29) disposed between the upper counter-matrices (19, 20) carried by the upper frame (13), said upper die member (29) having a cavity (30) having a shape corresponding to the shape of the central portion (8c) of the corrugation (8); and - a lower punch (31) disposed between the two lower die members (14, 15), opposite the upper die member (29), and having a shape complementary to the fingerprint ( 30) of the upper die member (29), the lower punch (31) being movably mounted on the lower frame (12), in said vertical direction intersecting with the edge axis, between a low rest position and a high folding position, in which, when the upper frame (13) is in its folding position, the lower punch (31) is engaged within the cavity (30) of the upper die element (29) to form the central portion (8c) of the corrugation (8), said folding method comprising: - positioning the corner piece (1) so that the wings (2, 3) of the corner piece are respectively in abutment against the bearing surface (17) of one and the other of the lower die elements (14, 15); The displacement of the two countermatrices (19, 20) towards their folding position and the movement of the lower punch (28) in its upper folding position to form the first and second end portions (8a, 8b) and the central portion (8c) of the corrugation (8). 18. Corner piece (1) for the construction of a sealing membrane of a fluid storage tank, the corner piece (1) having first and second wings (2, 3) ) planes inclined relative to each other and joining at an edge (4), said corner piece (1) having a corrugation (8) extending in a longitudinal direction secant to the edge (4), from one end to the other of the corner piece (1) so as to allow a deformation of the corner piece in a transverse direction, parallel to the edge (4); the corrugation (8) comprising: a first end portion (8a) disposed on the first flange (2), extending perpendicularly to the edge (4), from a first edge (7) of the corner piece (1) towards the edge (1); a second end portion (8b) disposed on the second flange (3) extending perpendicular to the edge (4) from a second edge (7) of the corner piece (1) opposite said first edge (7) towards the edge (4); - a central portion (8c), overlapping the edge (4), extending between the first and the second end portions (8b, 8c), in the extension of said first and second end portions (8a, 8b); the first and second end portions (8a, 8c) of the corrugation (8) protruding outwardly from the corner piece (1) and the central portion (8a) projecting inwardly from the corner piece (1). Angle piece (1) according to claim 18, wherein the central portion (8c) of the corrugation (8) has a semi-elliptical or triangular profile having a height which is increasing in the longitudinal direction of 20 the undulation (8) of each of the ends of the central portion (8c) towards a median section of the central portion (8c), along a bisecting plane at the angle formed between the first and the second wings (2, 3) . Angle piece (1) according to claim 18 or 19, wherein the central portion (8c) of the corrugation (8) is partially bordered by outwardly projecting corrugations (9a, 25b). of the corner piece (1), arranged on either side of the central portion (8c) and whose depth is decreasing in the direction of the edge (4). Angle piece (1) according to any one of claims 18 to 20, wherein the end portions (8a, 8b) of the corrugation have a semi-elliptical or triangular profile of constant depth. Angle piece (1) according to claim 21 when dependent on claim 19, wherein the middle section of the central portion (8c) of the corrugation (8) has a height equal to the depth extreme portions (8a, 8b) of the corrugation (8). Angle piece (1) according to any one of claims 18 to 22, wherein the geometrical configuration of the corner piece (1) is expandable in plan in the form of a rectangular piece. 24. Watertight and thermally insulating storage tank for a fluid comprising a secondary thermal insulation barrier retained to a supporting structure, a secondary sealing membrane supported by the secondary thermal insulation barrier, a primary thermal insulation barrier and a primary sealing membrane supported by the primary thermal insulation barrier and intended to be in contact with the fluid contained in the vessel, wherein: the secondary thermal insulation barrier comprises insulation blocks in the form of parallelepiped rectangle, juxtaposed in parallel rows and separated from each other by interstices; the secondary sealing membrane comprises a plurality of metal sheets comprising at least two orthogonal corrugations parallel to the sides of the thermal insulation blocks and inserted in the interstices formed between the insulation blocks or the slots formed in the insulation blocks and a plurality of corner pieces (1) according to any one of claims 18 to 23 connecting the metal sheets of adjacent first and second walls at the angle formed between said first and second walls . 25. Vessel (70) for the transport of a fluid, the vessel having a double hull (72) and a tank (71) according to claim 24, wherein the double hull 25 forms the outer bearing structure of the vessel. A method of loading or unloading a vessel (70) according to claim 25, wherein a fluid is conveyed through insulated pipes (73, 79, 76, 81) to or from a floating or land storage facility ( 77) to or from the vessel vessel (71). 30 27. Transfer system for a fluid, the system comprising a ship (70) according to claim 25, insulated pipes (73, 79, 76, 81) arranged to connect the tank (71) installed in the hull of the ship. at a floating or land storage facility (77) and a pump for driving fluid flow through the insulated pipelines from or to the floating or land storage facility to or from the vessel vessel.