Method for manufacturing metallic strip and bench

Abstract

To provide a method for manufacturing a metallic strip (10).SOLUTION: The end (13) of a first metallic strip element (11) and the end (14) of a second metallic strip element (12) placed side by side in a longitudinal direction are arranged on a flat support. Each of the first and second metallic strip elements (11 and 12) includes two opposite main surfaces (11A and 12A) connected by two longitudinal side surfaces (11B and 12B). Each of the end (13) of the first metallic strip element (11) and the end (14) of the second metallic strip element (12) is terminated on a horizontal end surface. The longitudinal side surfaces of the first and second metallic strip elements are aligned so as to extend linearly. The first and second metallic strip elements are butted and welded, and a continuous weld bead is formed along the horizontal end surface over the entire width of the elements.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the field of manufacturing metal strips for the construction of hermetic membranes, in particular for hermetic insulating tanks.

[0002] The present invention is particularly directed to liquefied natural gas (LNG), which is about −162° C. at atmospheric pressure, and liquid hydrogen (LH 2 ), and ammonia (NH 3 ), or for example tanks for transporting liquefied petroleum gas (LPG) at temperatures between -50°C and 0°C. These tanks can be installed on land or on floating structures. In the case of floating structures, the tanks are used for the transport of liquefied gas or for receiving liquefied gas to be used as propulsion fuel for the floating structures. In the case of land-based tanks or port storage structures, they can be installed on land or on the seabed and can be partially or completely buried. [Background technology]

[0003] For the construction of a sealed insulating tank membrane, a method is known for producing metal strips with a longitudinal length of 30-40 meters.

[0004] The production of such metal strips is described, for example, in patent application FR 2 148 366. The production of hermetically insulating tank membranes places great demands on the straightness of the metal strips.

[0005] The metal strip is stored wound around an axis perpendicular to its longitudinal direction. To prevent "sabre edge" deformations, it is unwound and straightened on a straightening bench and then placed on a shear bench where the longitudinal edges of the metal strip are cut and straightened.

[0006] The length of each straightening and shear bench is such that it can accommodate metal strips of about 30 to 40 meters in length. Summary of the Invention

[0007] One idea behind the present invention is to provide a manufacturing method which allows very long metal strips, for example lengths of 50 to 80 meters, to be produced in a small space.

[0008] In particular, it is problematic to produce very long metal strips using production benches that are shorter than the length of the metal strip to be produced, for example production benches that are less than 40 metres in length.

[0009] One embodiment of the present invention comprises: 1. A method for producing a metal strip, comprising the steps of: - placing an end of a first metal strip element and an end of a second metal strip element on a planar support, the end of the first metal strip element and the end of the second metal strip element being longitudinally juxtaposed, each of the first and second metal strip elements having two opposite main faces connected by two longitudinal sides, the first and second metal elements having the same width, the end of the first metal strip element and each of the end of the second metal strip element being terminated by a corresponding lateral end face, whereby each of the main faces of the first and second metal strip elements rests at least partially on the planar support and the lateral end face of the end of the first metal strip element extends in the vicinity of the lateral end face of the end of the second metal strip element; - aligning the longitudinal sides of the first and second metal strip elements so that they extend in line with one another; - butt welding the first and second metal strip elements to form a continuous weld bead along the lateral end faces across the entire width of the metal strip elements; The present invention provides a method comprising:

[0010] These features allow the production of very long metal strips by welding several metal strip elements together. Moreover, the method allows the use of a production bench of a length that is completely capable of accommodating a single metal strip element, and therefore does not require the provision of a straightening and / or shear bench capable of accommodating the final length of metal strip obtained according to the production method.

[0011] The longitudinal edges of the resulting metal strip are preferably cut at least along a region extending in the longitudinal direction of the metal strip from one side of the weld bead to the other side of the weld bead.

[0012] Thus, the longitudinal edges of the portion of the metal strip containing the weld bead are cut off after said weld has been made, which has the advantage of removing initial and final areas of the weld that may contain weld defects.

[0013] Embodiments of such methods may have one or more of the following features.

[0014] In one embodiment, the ends are positioned such that the lateral end face of the end of the first metal strip element extends from the lateral end face of the end of the second metal strip element a distance of less than half the thickness of one of the metal strip elements.

[0015] In another embodiment, the ends are positioned such that the lateral end face of the end of the second metal strip element overlaps the end of the first metal strip element over a distance of less than or equal to three times the thickness of one of the metal strip elements.

[0016] In practice, therefore, the ends of the first and second metal strip elements are arranged with their lateral end faces extending towards each other and are separated from each other by a space whose longitudinal dimension of the metal strip elements is not more than half the thickness of one of the metal strip elements, for example not more than half the thickness of the thicker of the two metal strip elements, or such that the end of the second metal strip element overlaps the end of the first metal strip element over a distance measured in the longitudinal direction of the metal strip element that is not more than half the thickness of one of the metal strip elements, for example not more than three times the thickness of the thicker of the two metal strip elements.

[0017] An embodiment of the method further comprises: - unwinding a roll carrying said first metal strip element Includes.

[0018] An embodiment of the method further comprises: - partially cutting the first metal strip element along its longitudinal sides using two tools arranged on a path for feeding the end of the first metal strip element to a cutting stop position located away from the lateral end face of the first metal strip element intended to be located adjacent to the second metal strip element, Includes.

[0019] Thus, the longitudinal edges of the first metal strip element can be partially cut before welding to the second metal strip element, which allows the mechanical strength of the welded metal strip to be improved by cutting the start and end of the welded area along the longitudinal sides after welding to eliminate weld defects.

[0020] In one embodiment, the two cutting tools are arranged opposite each other and are not movable. The metal strip element is driven and moved in the longitudinal direction. The planar support includes a conveyor which may be equipped with a device for moving the metal strip element, for example a suction system for obtaining a suction effect to hold the metal strip element or an attachment system fixed to the ends of the metal strip element.

[0021] In one embodiment, the two cutting tools are arranged opposite each other and are movable in the longitudinal direction, for example the cutting tools being movably mounted on guide rails parallel to the longitudinal axis of the production bench.

[0022] In one embodiment, the method further comprises: - winding the cut ends of the first metal strip element around a winding axis perpendicular to the longitudinal direction. Includes.

[0023] This step frees the planar support to receive the second metal strip element.

[0024] In one embodiment, prior to the welding step, a portion of the second metal strip element is also cut along the longitudinal side, the cut portion of the second metal strip element extending from a lateral end face of the second metal strip element to a cut stop position located away from the lateral end face of the second metal strip element intended to be placed adjacent to the first metal strip element.

[0025] In one embodiment, the planar support comprises a metal plate, and the lateral end faces of the first and second metal strip elements arranged adjacent to one another extend facing the metal plate during the welding step.

[0026] In one embodiment, the method further comprises: - pressing the ends of the first and second metal strip elements against the planar support by abutting the opposite main faces of the planar support on either side of the lateral end faces arranged adjacent to one another. Includes.

[0027] In one embodiment, the step of pressing the ends of the first and second metal strip elements against the planar support employs a clamping device, the clamping device including metal abutments abutting the main surfaces of the metal strip elements on either side of the lateral end faces of the metal strip elements arranged adjacent to each other.

[0028] In one embodiment, the method further comprises: - performing spot welding before generating the continuous weld bead Includes.

[0029] In one embodiment, the continuous weld bead is produced by a method selected from TIG arc welding, microplasma welding, spallation seam welding, and mastication friction welding.

[0030] In one embodiment, each metal strip element is greater than 25 meters in length.

[0031] In one embodiment, the thickness of each metal strip element is constant.

[0032] In one embodiment, the first and second metal strip elements have the same thickness.

[0033] In one embodiment, the cutting stop position is located at a distance of 1 meter to 3 meters from the lateral end face of the cut first or second metal strip element.

[0034] In one embodiment, the metal strip element is made using an alloy of iron and nickel, the coefficient of expansion of which is typically 1×10 -6 More than 2×10 -6 K -1or the metal strip element is made using an alloy of iron and manganese, the coefficient of expansion of which is 7×10 -6 K -1 More than 9×10 -6 K -1 The following is the result.

[0035] In one embodiment, each of said metal strip elements has a thickness of 0.5 to 1 mm.

[0036] In one embodiment, the method of manufacture further comprises bending the longitudinal edges of the metal strip.

[0037] In one embodiment, the present invention further comprises: A bench for manufacturing metal strip, comprising: a planar support adapted to receive an end of a first metal strip element and an end of a second metal strip element, said end of the first metal strip element and said end of the second metal strip element being longitudinally juxtaposed, each of said first and second metal strip elements having two opposite main faces connected by two longitudinal sides, each of said end of the first metal strip element and each of said end of the second metal strip element being terminated by a corresponding lateral end face, said lateral end face of said first metal strip element extending in the vicinity of said lateral end face of said second metal strip element; an alignment device for aligning the relative positions of the longitudinal sides of the first and second metal strip elements so that they extend in line with one another; a welding gantry for butt-welding the two metal strip elements with a continuous weld bead extending along the lateral end faces over the entire width of the metal strip elements; To provide a bench comprising:

[0038] The bench preferably includes two cutting tools adapted to cut the resulting cut longitudinal edges of the metal strip at least along an area extending in the longitudinal direction of the metal strip from one side of the weld bead to the other side of the weld bead.

[0039] In one embodiment, the planar support includes a groove adapted to receive an end of the metal strip element.

[0040] In one embodiment, the alignment device comprises, on the one hand, a fixed main part including a bottom wall and a first longitudinal side wall bounding the groove, and, on the other hand, a movable side part including a second side wall facing the first side wall, the movable side part of the alignment device being adapted to clamp an end of a metal strip element arranged in the groove in a transverse direction perpendicular to the longitudinal direction.

[0041] In one embodiment, the movable side of the alignment device is now adapted to slide laterally within the main part of the alignment device between an open position and a clamped position, where in the open position the second side wall is positioned at a distance from the first side wall strictly greater than the width of the metal strip element, and where in the clamped position the second side wall is positioned at a distance from the first side wall less than or equal to the width of the metal strip element.

[0042] In one embodiment, the production bench includes a clamping device adapted to press two metal strip elements against a main surface opposite the support surface, on either side of lateral end faces arranged adjacent to one another, against a planar support.

[0043] In one embodiment, the clamping device takes the form of a first metal plate with through slots intended to extend laterally facing the mutually adjacently arranged lateral end faces of a metal strip element received on a planar support.

[0044] In one embodiment, the production bench comprises a second plate forming part of the planar support and intended to be placed facing the lateral end face arranged close to the metal strip element.

[0045] In one embodiment, the second plate is made of ceramic or metal, more specifically copper and its alloys, or stainless steel.

[0046] In one embodiment, the welding gantry includes a welding head and a guide rail, the welding head configured to slide along the rail such that the welding head moves within the slot of the first metal plate.

[0047] An embodiment of the present invention also comprises: A metal strake suitable for producing a sealing membrane for a sealed insulated tank, comprising: A metal strip obtained by the above method from two metal strip elements each having a constant thickness over their entire length Equipped with The metal strake has a planar central portion in the width direction thereof and two lateral limbs bent substantially perpendicularly to the planar central portion, the two lateral limbs having a small width compared to the planar central portion.

[0048] An embodiment of the present invention further comprises: A sealing membrane for a sealed insulated tank, comprising: a repeating structure including alternating metal strakes and elongated weld flanges connected to the support surface of the sealing membrane and projecting toward the sealing membrane; Equipped with the weld flange extends parallel to the metal strake for at least a portion of the length of the metal strake; the planar central portion of the metal strake is placed on the support surface and the lateral edges of the metal strake are placed against the adjacent weld flanges and hermetically welded to the weld flanges; Provide a sealing membrane.

[0049] An embodiment of the present invention further comprises: 1. A sealed, insulated tank integrated into a support structure, comprising: the support structure includes a plurality of support walls; the tank includes a plurality of tank walls, each of which is secured to a corresponding one of the support walls; the tank wall includes an insulating barrier supported on the support wall; the insulating barrier comprises a planar support surface parallel to the corresponding support wall and the sealing membrane; Provide a sealed insulated tank.

[0050] An embodiment of the present invention further comprises: 1. A vessel for transporting a fluid, comprising: Double hull and The tank disposed within the double hull; The present invention provides a ship equipped with:

[0051] An embodiment of the present invention further comprises a fluid transfer system, comprising: Ships and an insulated pipe arranged to connect the vessel's tank to a floating or land-based storage facility; a pump for pumping fluid from the floating or onshore storage facility to the tank on the ship or from the tank on the ship to the floating or onshore storage facility through the insulated pipe; The present invention provides a system including:

[0052] An embodiment of the present invention further provides a method of loading or unloading a ship, in which fluid is supplied from a floating or land-based storage facility to the ship's tanks or from the ship's tanks to the floating or land-based storage facility through insulated pipes.

[0053] The invention will be better understood and other objects, details, features and advantages of the invention will become more apparent from the following description of certain embodiments thereof, given by way of non-limiting example only and with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0054] [Figure 1]FIG. 1 is a schematic, partially transparent view of a bench for producing metal strip. [Diagram 2] FIG. 2 is a schematic view of a bench for manufacturing the metal strip of FIG. 1, taken along the line AA. [Diagram 3] FIG. 3 is a schematic enlarged view of detail B of FIG. [Figure 4] FIG. 4 is a schematic top view of a portion of the manufacturing bench of FIG. [Diagram 5] FIG. 5 illustrates diagrammatically four steps of a method for manufacturing a metal strip. [Figure 6] FIG. 6 diagrammatically represents a profile diagram of the configuration of the ends of a metal strip element during seam welding and a cross section of the metal strip obtained after such welding. [Figure 7] FIG. 7 is a schematic cross-sectional view of a methane tanker ship's tank and a terminal for loading / unloading the tank. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] The attached figures show part of a bench for manufacturing metal strips and the various steps of their manufacture, in which identical or corresponding elements shown are referred to by the same reference numerals and will not each time be described in detail.

[0056] 1, 2 and 3, a partial view of one embodiment of a bench 20 for manufacturing a metal strip 10 is shown.

[0057] This production bench 20 allows the use of the method to produce very long metal strips 10, for example lengths of 50 meters or more.

[0058] In the method of manufacturing a metal strip described herein, a metal strip 10 is manufactured from a plurality of metal strip elements 11, 12, for example at least two metal strip elements.

[0059] In the following, the situation will be described where a metal strip 10 is produced from a first metal strip 11 and a second metal strip element 12 .

[0060] Each metal strip element 11, 12 is in the form of a ribbon elongated in a longitudinal direction D1, D2 and has a linear profile in a direction perpendicular to the longitudinal direction.

[0061] It comprises two opposing main faces 11A, 12A which are connected by two longitudinal side faces 11B, 12B and by two lateral end faces 11C, 12C (Figures 1 and 6).

[0062] Each metal strip element 11, 12 typically has a length in the longitudinal direction D1, D2 of about 25 to 40 meters, for example 35 meters, and a width slightly greater than 540 millimeters in a direction perpendicular to the longitudinal direction and extending parallel to the main faces 11A, 12A of the metal strips 11, 12. The width of the metal strip element is, for example, greater than 540 millimeters and less than 560 millimeters.

[0063] The nominal thickness of the metal strip elements 11, 12 is about 0.7 mm, for example, greater than or equal to 0.5 and less than or equal to 1 mm.

[0064] Each metal strip element has a uniform and constant thickness over its entire length, which is equal to its nominal thickness and has a tolerance strictly less than 5%, i.e. less than 0.035 mm for a nominal thickness of 0.7 mm. The thickness of each metal strip element therefore varies locally by less than 5% of the nominal thickness of the metal strip element. Here, it is preferred that the thickness of each metal strip element varies locally by less than 4%, 3%, 2% or 1% of the nominal thickness.

[0065] The first and second metal strip elements preferably have the same width and thickness. Their lengths may be the same or different.

[0066] The first and second metal strip elements are each made of a metal, for example an alloy of iron and nickel, whose coefficient of expansion is typically 2×10 -6 K -1 Less than, for example, 1×10 -6 ~2×10 -6 K -1 This is, for example, the "Invar" alloy. In another embodiment, each metal strip element is made of an alloy of iron and manganese, whose expansion coefficient is 7×10 -6 K -1 More than 9×10 -6 K -1 This alloy generally allows for cost savings.

[0067] The method for producing the metal strip 10 comprises: - placing the end 13 of the first metal strip element 11 and the end 14 of the second metal strip element 12 on a planar support 21; - aligning the longitudinal sides 11B, 12B of the first metal strip element 11 and the second metal strip element 12 so that they extend in a straight line with each other; - butt-welding the first metal strip element 11 and the second metal strip element 12 to form a continuous weld bead extending along the entire width of the first metal strip element and the lateral end faces 11C, 12C of the second metal strip element; It is equipped with.

[0068] In practice, each metal strip element 11, 12 is initially stored in the form of a roll in which the metal strip element is wound up about an axis extending across the width of the metal strip element.

[0069] The method therefore includes a preliminary step in which a roll carrying a first metal strip element 11 is unwound.

[0070] Immediately after being unwound, the metal strip element 11 may exhibit a so-called "sabre blade" deformation, in which both longitudinal edges of the metal strip element are curved in the same direction. The use of such metal strip elements without correcting this deformation makes it impossible to produce a metal strip with straightness and dimensional accuracy that meets the level of accuracy required for the production of hermetic membranes.

[0071] In practice, the required accuracy is of the order of 0.5 mm per metre (not cumulative), i.e. over the entire length of the metal strip, no longitudinal edge of the metal strip may deviate more than 0.5 mm from a theoretically ideal straight line extending between the two longitudinal ends of that longitudinal edge.

[0072] To correct this deformation, the method of manufacturing the metal strip includes a step of stretching the first metal strip element 11 .

[0073] The first metal strip element 12 is therefore preferably stretched under tension in a straightening device, which is known to those skilled in the art and will not be described in detail here. The straightening device comprises, for example, two self-clamping jaws, one fixedly fixed to a fixed frame of the straightening device and the other one movable since it is part of a slidable part on the frame. The end 13 of the first metal strip element 11 is placed in the self-clamping jaw, which slides so as to apply a longitudinal traction force to the first metal strip element 11. This longitudinal traction force is slightly greater than the elastic deformation limit of the metal strip element.

[0074] The stretched and straightened first metal strip element 11 is laid flat on a planar support 21 of a production bench 20 (see schematic diagram a in FIG. 5 ). After leaving the straightening device, the first metal strip element may be unwound and transported to the production bench 20, where it is straightened and laid flat on the planar support 21 of the production bench 20.

[0075] The planar support 21 comprises a planar receiving surface capable of receiving the first or second metal strip element spread out completely flat (schematic representation a in FIG. 5).

[0076] The planar support 21 extends along a longitudinal axis L. The metal strip elements are placed on the planar support 21 such that the longitudinal directions D1, D2 of the metal strip elements 11, 12 extend along the longitudinal axis L of the planar support.

[0077] The manufacturing method preferably comprises a step of partially cutting the first metal strip element 11 along its longitudinal side 11B up to a cutting stop position AD located away from a lateral end face 11C of the first metal strip element 11 intended to be placed in the vicinity of the second metal strip element 12.

[0078] This cleavage step is shown diagrammatically in FIG. 5, diagram b.

[0079] The longitudinal edges of the first metal strip element 11 are cut by two cutting tools 22 arranged on the path along which the ends 13 of the first metal strip element 11 are fed.

[0080] In the example shown in Fig. 5, two cutting tools 22 are arranged opposite each other and cannot be moved. Each cutting tool 22 comprises, for example, a shear tool with two circular cutters. The cutting tools 22 are arranged at the longitudinal ends of a planar support 21 of the production bench.

[0081] Here, the first metal strip element 11 is moved by a conveyor which may be equipped with a suction system to obtain a suction effect holding the metal strip element or with attachments fixed to the ends of the metal strip element, and thus moves in a translational longitudinal direction along the longitudinal axis L of the planar support 21 parallel to the longitudinal direction D1 of the first metal strip element 11, until the cutting tool reaches a cutting stop position AD (schematic diagram c in FIG. 5).

[0082] The cutting stop position AD is, for example, located at a distance of 1 meter to 3 meters from the lateral end face 11C of the first metal strip element 11.

[0083] For this purpose, the cutting tool is arranged downstream of the welding gantry 50 in the longitudinal direction L of the production bench, in the direction of movement of the first metal strip element.

[0084] Alternatively, the two cutting tools may be arranged opposite each other and be movable in the longitudinal direction. The two cutting tools 22 are mounted on a frame which can translate along rails which extend along a planar support along the longitudinal axis L of the support surface 21, for example. They can translate in the longitudinal direction L of the production bench, in one or both directions of this longitudinal direction.

[0085] In this case, the bench may or may not include a device for moving the metal strip elements: if it does not include such a device, the two cutting tools are at least movable between the two ends on either side of the welding gantry.

[0086] Once the longitudinal edge of the first metal strip element 11 has been cut, the cut portion of the first metal strip element is preferably unwound about a winding axis perpendicular to the longitudinal direction D1 of the first metal strip element 11. This is shown in schematic diagram c of Figure 5.

[0087] Thus, at the end of this cutting step, the first metal strip element 11 comprises the unwound cut portion and a part of the first metal strip element 11 between the cutting stop position AD and the nearest lateral end face 11C, said part of the first metal strip element 11 having an uncut longitudinal edge and located on the main support 21. Said part of the first metal strip element 11 constitutes the end 13 of the first metal strip element 11.

[0088] The space occupied by the first metal strip element 11 on the planar support 21 is limited to its ends 13. This allows the second metal strip element 12 to be placed flat on the planar support 21 (schematic representation c in FIG. 5).

[0089] The method preferably includes a preliminary step in which a roll formed by the second metal strip element 12 is unwound.

[0090] The method of manufacturing the metal strip preferably further comprises the step of stretching the second metal strip element 12 to prevent "sabre blade" type deformation.

[0091] Therefore, the second metal strip element 12 is preferably stretched under tension in a straightening device, as described above.

[0092] The stretched and straightened second metal strip element 12 is placed on a planar support 21 of a production bench 20 (see schematic diagram c in FIG. 5). After leaving the straightening device, the second metal strip element 12 may be unwound and transported to the production bench 20, where it may then be straightened and placed on the planar support 21.

[0093] The second metal strip element 12 is placed alongside the first metal strip element such that the end 13 of the first metal strip element and the end 14 of the second metal strip element 12 are aligned longitudinally. In this case, the longitudinal direction D1 of the first metal strip element 11 and the longitudinal direction D2 of the second metal strip element 12 are parallel.

[0094] One of the main faces 11A, 12A of each of the first and second metal strip elements 11, 12 rests at least partially on a receiving surface of a production bench 20. The parts of these main faces 11A, 12A which belong to the ends of the first and second metal strip elements rest in particular on a planar support 21.

[0095] A lateral end 11C of the end 13 of the first metal strip element 11 extends close to a lateral end face 12C of the end 14 of the second metal strip element 12.

[0096] More precisely, two configurations are envisaged in which the lateral end faces 11C, 12C of the first and second metal strip elements extend close to one another.

[0097] In a first possible configuration, the lateral end face 11C of the end of the first metal strip element is located at a distance extending from the lateral end face 11C of the end of the second metal strip element by a distance equal to or less than half the thickness of each metal strip element.

[0098] More precisely, the lateral end face 11C of the first metal strip element 11 faces and extends towards the lateral end face 12C of the second metal strip element 12, either in contact with it or spaced therefrom by a distance not greater than half the thickness of each metal strip element. This first configuration is shown in FIG.

[0099] In a second possible configuration, the end 14 of the second metal strip element 12 slightly overlaps the end 13 of the first metal strip element over a distance of no more than three times the thickness of each metal strip element. This second configuration is shown in Figure 6. In this second configuration, the lateral end faces 11C, 12C of the first and second metal strip elements are separated by a distance measured in the longitudinal direction of the metal strip elements that is no more than three times the thickness of one of the metal strip elements.

[0100] The lateral end faces 11C, 12C of the two metal strip elements are preferably straight, i.e. perpendicular to the main faces of the metal strip elements, as shown in Figures 3 and 6. Furthermore, in the two configurations envisaged, the lateral end faces 11C, 12C of the first and second metal strip elements 11, 12 are separated by a distance measured in the longitudinal direction of the metal strip elements that is no greater than three times the thickness of one of the metal strip elements.

[0101] The lateral end faces 11C, 12C of the two metal strip elements are preferably arranged in contact with each other.

[0102] This configuration is used, for example, in TIG, plasma, or mastication friction welding.

[0103] The planar support 21 further comprises grooves 24 adapted to receive the ends 13,14 of the metal strip elements 11,12.

[0104] In order to position the ends of the first and second metal strip elements 11, 12 precisely in line with each other, the method includes aligning the longitudinal sides 11B, 12B of the first and second metal strip elements so that they extend in line with each other.

[0105] To this end, the manufacturing apparatus 20 includes an alignment device 30 for adjusting the relative positions of the longitudinal sides 11B, 12B of the first and second metal strip elements 11, 12 so that they extend in line with one another.

[0106] In figure 4 there is shown a portion of the planar support 21 which is intended to extend under the ends 13, 14 of the first and second metal strip elements 11, 12. This portion of the planar support includes two complementary portions 31, 32 which together form an alignment device 30.

[0107] More precisely, here the alignment device 30 comprises, on the one hand, a fixed main part 31 including a first side wall 31A and a bottom wall 31B, the first side outer surface 33 and the central outer surface 34 of which define the groove 24, and, on the other hand, the alignment device 30 comprises a movable side part 32 including a second side wall 32A and a second outer surface 35, the second outer surface 35 facing the first side outer surface 33 of the first side wall 31A defining the groove 24.

[0108] The movable side 32 of the alignment device 30 is configured to clamp the ends 13, 14 of the metal strip elements 11, 12 disposed in the grooves 24 in a transverse direction perpendicular to the longitudinal direction L of the production bench.

[0109] The movable side part 32 of the alignment device 30 is here adapted to slide laterally within the fixed main part 31 of the alignment device 30. To this end, the movable side part 32 comprises a series of pins 36 which project from the second side wall 32A towards the fixed main part 31, which comprises in its bottom wall 31B a housing 37 which is open towards the pins 36 and which is adapted to receive the pins 36 sliding therein.

[0110] The movable side 32 is thus adapted to slide between an open position and a clamped position, in which the second side wall is located at a distance from the first side wall strictly greater than the width of the metal strip element, and in which the second side wall is located at a distance from the first side wall equal to the width of the metal strip element.

[0111] To align the ends of the first and second metal strip elements, the movable part 32 of the alignment device 30 is slid to sandwich the longitudinal side surfaces 11B, 12B of the two metal strip elements between the outer side surfaces 33, 35 (between the outer side surface 33 of the side wall 31A of the fixed main part 31 of the alignment device 30 and the outer side surface 35 of the second side wall 32A of the movable part 32). This causes the longitudinal side surfaces 11B, 12B of the two metal strip elements to extend in a straight line with each other, and the ends 13, 14 of the two metal strip elements to be perfectly aligned.

[0112] The step of butt-welding the first and second metal strip elements 11, 12 can be carried out in various ways. This step is represented diagrammatically by the arrow W in the schematic diagram c of figure 5.

[0113] The continuous weld bead is produced by a process selected from, for example, TIG (tungsten inert gas) arc welding, plasma or microplasma welding, seam welding by spallation, mastication friction welding.

[0114] In the examples shown in Figures 1 to 3, the welding is TIG arc welding or plasma welding.

[0115] To ensure accurate welding of the two metal strip elements, the method includes a step of pressing the ends 13, 14 of the first and second metal strip elements 11, 12 against the planar support 21 by abutting them against opposite main surfaces 11A, 12A of the planar support 21 on both sides of their lateral end faces 11C, 12C arranged closely to one another.

[0116] This step allows for proper positioning of the ends of the metal strip elements during welding and prevents defects associated with thermal deformation of the metal strip elements due to heating of the material during welding.

[0117] In practice, the step of pressing the ends of the first and second metal strip elements against the planar support is carried out using a clamping device 40, which includes metal abutment portions 41 abutting the main surfaces of the metal strip elements 11, 12 on both sides of the lateral end faces of the metal strip elements arranged adjacent to each other.

[0118] An example of such a clamping device 40 is shown diagrammatically in Figures 1 and 3. The metal abutment is formed by a first plate with a central slot 42.

[0119] The first plate has a length which is greater than the length of the metal strip elements 11, 12 measured in the transverse direction.

[0120] The ends of the first plate of the clamping device 40 rest on the first and second side walls 31A, 32A of the alignment device 30 and are pressed against them by a cylinder system, not shown, which is rigidly fixed to the alignment device 30 or to the welding gantry 50. The depth of the grooves 24 formed by the alignment device 30 is preferably equal to or greater than the thickness of each strip element.

[0121] Thus, when the first plate of the clamping device 40 is pressed against the alignment device after the alignment step, the first plate clamps the ends 13,14 of the metal strip elements 11,12 against the bottom of the groove 24.

[0122] The slot 42 in the first plate extends beyond the outer faces of the first and second side walls 31A, 32A of the alignment device 30 and therefore beyond the longitudinal sides 11B, 12B of the metal strip elements 11, 12, allowing completely free access to the lateral end faces 11C, 12C of the metal strip elements 11, 12. The slot 42 preferably has lateral edges that diverge away from the support surface.

[0123] The first plate is a metal plate, preferably made of a metal with high thermal conductivity, such as copper or its alloys, which facilitates the evacuation of heat and limits the heating of the ends of the metal strip element.

[0124] The welding is performed using a welding gantry 50. The welding gantry 50 includes a welding head 53 and a guide rail 51.

[0125] The guide rail 51 extends facing the slot 42 of the first plate 41 of the clamping device 40. The guide rail 51 is supported, for example, by an erected wall 54 which rises from the first side wall 31A of the fixed main part 31 and the second side wall 32A of the movable side part 32 of the alignment device 30. The welding head 53 is, for example, composed of an electrode 52 for a TIG or plasma torch used for welding. The welding head 53 and its electrode 52 are configured to slide along the rail 51, and the electrode 52 moves in the slot 42 of the first metal plate 41 (FIG. 3).

[0126] Prior to producing the continuous weld bead, the method may include a spot welding step, preferably performed every maximum of 5 centimeters.

[0127] This step makes it possible to limit deformation of the ends 13, 14 of the metal strip elements 11, 12 during the final welding.

[0128] For welding the metal strip elements 11, 12, the planar support 21 of the production bench 20 preferably comprises a second plate 60. The second plate 60 is, for example, part of the bottom wall 31B of the fixed main part 31 of the alignment device 30 (FIG. 3).

[0129] The second plate 60 is received within this bottom wall 31B and is flush with the central outer surface 34 of the groove 24. The second plate 60 is positioned facing the slot 42 of the first plate 41 and the guide rail 51 of the welding gantry 50.

[0130] Thus, the lateral end faces of the first and second metal strip elements 11, 12 arranged adjacent to one another extend facing the metal plate during the welding step.

[0131] The second plate may be made of ceramic or metal, preferably a metal with high thermal conductivity such as copper or a copper alloy, which will help to dissipate heat during welding and limit heating of the ends of the metal strip elements. If copper or a copper-based alloy is used, the second plate must be provided with grooves (not shown) to accommodate the areas to be welded.

[0132] The weld beads are formed by melting a portion of each metal strip element adjacent its lateral end face, with or without the addition of filler metal.

[0133] Once the two metal strip elements 11, 12 have been welded to form the metal strip 10, the longitudinal edges of the resulting metal strip are cut at least along a region extending from one side of the weld bead to the other side of the weld bead in the longitudinal direction of the metal strip 10. This step is represented diagrammatically in diagram d of FIG.

[0134] Cutting the longitudinal edge of the metal strip 10 at the level of the weld bead after the weld bead has the advantage that weld defects occurring at the beginning and end of the welding step, i.e. in the immediate vicinity of the longitudinal sides 11B, 12B of the metal strip element, can be eliminated. The remaining longitudinal edge of the second metal strip element is then cut. This cutting is carried out using the cutting tool 22 described above.

[0135] In the embodiment described here, the longitudinal edge of the metal strip is cut from the cutting stop location of the first metal strip element to a location opposite the weld bead, for example to the free end of the metal strip element 10 .

[0136] Alternatively, prior to the welding step, a longitudinal edge of a portion of the second metal strip element is also cut along its longitudinal side, the cut portion of the second metal strip element extending from a lateral end face of this second metal strip element to a cut stop position located away from the lateral end face of the second metal strip element intended to be placed in the vicinity of the first metal strip element, the stop position also being located at a distance preferably between 1 meter and 3 meters from the lateral end face of the second metal strip element intended to be placed in the vicinity of the first metal strip element.

[0137] In this case, after welding the metal strip elements, the longitudinal edges of the resulting metal strip are cut between a cutting stop position of the first metal strip element and a cutting stop position of the second metal strip element.

[0138] The metal strip 10 obtained is, for example, wound about a transverse axis perpendicular to its longitudinal directions D1, D2.

[0139] The resulting thickness of the metal strip 10 is uniform and constant over its entire length, except for possible slight local thickening due to the weld beads.

[0140] In a further step of the manufacturing method, a bending of the longitudinal edges of the metal strip can be carried out directly inside the tank, in order to form strakes which can be used to manufacture the sealing membrane of the tank, as explained at the beginning.

[0141] The above described manufacturing method has the advantage of being simple and economical. Moreover, the chemical strength test of the 40 mm wide and 0.7 mm thick metal strip obtained after the above described butt welding showed a mechanical strength of 13 kN, which is more than 20 percent higher than the mechanical strength of the 40 mm wide metal strip obtained by 1 mm / 0.7 mm fillet welding.

[0142] Furthermore, plasma welding tests using a high current of 50 A, a low current of 30 A, a low current / high current time ratio of 70%, a speed of 35 cm / min and a frequency of 4 Hz produce a high quality weld bead with little excess thickness and no deformation at the weld joint level between the first and second metal strip elements.

[0143] TIG welding tests using a high current of 45 A, a low current of 20 A, a low / high current time ratio of 45%, a speed of 20 cm / min and a frequency of 10 Hz also produce a high quality weld bead with almost no excess thickness and no deformation at the joint level of the first and second metal strip elements.

[0144] In another embodiment of the manufacturing method, the welding is butt welding and crimping, for example performed by seam welding and crimping. Figure 6 shows diagrammatically the ends 13, 14 of the first and second metal strip elements and two electrodes 70 in the form of wheels (copper disks or knurling wheels) rotating in opposite directions. The two electrodes are capable of heating the longitudinal edges by passing a high frequency current as well as applying a crimping force to the longitudinal edges to perform a continuous weld. The planar support comprises a passage through which the electrodes pass, located under the metal strip elements.

[0145] By butt welding with crimping, a metal strip 10 as shown in FIG. 6 can be obtained.

[0146] The metal strip 10 produced by this method is intended to be used for the construction of a hermetic membrane for a hermetic insulating tank.

[0147] For this purpose, the metal strip obtained by the method described above is used to form metal strakes with raised edges intended for the production of sealing membranes inside the tank.

[0148] A metal strake is a metal strip obtained by the method described above from two metal strip elements each having a constant thickness over their entire length.

[0149] The metal strake has a planar central portion across its width and two lateral limbs bent substantially perpendicular to the planar central portion, the two lateral limbs being narrower than the planar central portion.

[0150] The raised edges of the metal strakes are obtained from the metal strip using a bending device with three rollers on either side of the metal strip. The rollers apply pressure to the metal strip, deforming it to produce the raised edges. The finished sealing membrane contains a continuous layer of metal strakes with raised edges.

[0151] The raised edges of the metal strakes are welded to parallel weld supports fixed within the underlying insulating barrier.

[0152] The successive layers therefore have a repeating structure which includes alternating metal strakes as described above and elongated weld flanges which form the weld supports.

[0153] A surface of the underlying insulating barrier facing the sealing membrane forms a surface for supporting the sealing membrane. Each weld flange is connected to and projects relative to the support surface.

[0154] The sealed, insulated tank is integrated into a support structure that includes a plurality of support walls, and the tank includes a plurality of tank walls each secured to a corresponding support wall.

[0155] The support wall is in particular formed by the hull or double hull of the ship and typically forms part of a support structure comprising a number of walls defining the overall shape of the tank, usually a polyhedral shape.

[0156] The sealed and insulated tank is formed by assembling a number of tank walls, which in the case of LNG typically comprise, in succession from the outside to the inside of the tank in the thickness direction, a secondary insulating barrier held by a support wall, a secondary sealing membrane in contact with the secondary insulating barrier, a primary insulating barrier in contact with the secondary sealing membrane, and a primary sealing membrane intended to be in contact with the liquefied natural gas in the tank.

[0157] When there are two sealing membranes, the primary sealing membrane can be the same as the secondary sealing membrane or can be different. Each of the two sealing membranes in the tank wall can be manufactured as described above.

[0158] At the height of the corner between the two tank walls, the secondary sealing membranes of the two tank walls and / or the primary sealing membranes of the two walls may be connected by a connecting ring in the form of a square tube. The connecting ring forms a structure that is able to absorb tension forces caused in particular by thermal contraction of the metal elements forming the sealing membranes, by deformations of the ship's hull at sea and by cargo movements. One possible structure of the connecting ring is explained in more detail in patent application FR 2 549 575 A1.

[0159] The secondary insulation barrier includes a plurality of secondary insulation blocks and the primary insulation barrier includes a plurality of primary insulation blocks, which may have the general shape of, for example, a parallelepiped and may be fixed to the supporting wall in various ways, for example by anchor members.

[0160] The support surface of the sealing membrane of each insulating barrier is planar and parallel to its respective supporting wall.

[0161] Such membranes can withstand liquefied natural gas (LNG), which is about -162°C at atmospheric pressure, and liquid hydrogen (LH 2 ), and ammonia (NH 3 ) or cryogenic liquids, e.g. liquefied petroleum gas (LPG) at temperatures between -50°C and 0°C. These tanks can be located on land or on floating structures. In the case of floating structures, the tanks are used for the transportation of liquefied gas or for receiving liquefied gas to be used as a propulsion fuel for the floating structure. In the case of onshore tanks or port storage structures, they are located on land or on the seabed and are partially or completely buried.

[0162] The tank wall may consist of only one sealing membrane and one insulating barrier, for example when storing LPG.

[0163] Referring to Figure 7, a cross-section of a methane tanker ship 70 shows a prismatic sealed insulated tank 71 mounted on the ship's double hull 72. The walls of the tank 71 include a primary containment barrier intended to be in contact with the LNG in the tank, a secondary containment barrier arranged between the primary containment barrier and the ship's double hull 72, and two insulating barriers arranged respectively between the primary containment barrier and the secondary containment barrier and between the secondary containment barrier and the double hull 72.

[0164] In a manner known per se, a loading / unloading pipe 73 arranged on the upper deck of the ship can be connected by suitable connectors to an offshore or port terminal, or to an LNG bunkering vessel, to transfer a cargo of liquefied natural gas to or from the tanks 71.

[0165] FIG. 7 shows an example of a marine terminal including a loading and unloading station 75, an underwater pipe 76, and an onshore facility 77. The loading and unloading station 75 is a fixed offshore facility including a moving arm 74 and a tower 78 supporting the moving arm 74. The moving arm 74 carries a bundle of insulated flexible tubes 79 that can be connected to a loading / unloading pipe 73. The rotatable moving arm 74 accommodates methane tankers of any size. A connecting pipe, not shown, extends into the tower 78. The loading and unloading station 75 allows the methane tanker 70 to be loaded from or unloaded to the onshore facility 77. The onshore facility 77 includes a liquefied gas storage tank 80 and a connecting pipe 81 connected to the loading or unloading station 75 through the underwater pipe 76. Underwater pipes 76 allow liquefied gas to be transported over long distances, for example 5 km, between the loading or unloading station 75 and the onshore facility 77, allowing the methane tanker vessel 70 to remain away from shore during loading and unloading operations.

[0166] Pumps on board the ship 70 and / or pumps provided at the onshore facility 77 and / or pumps provided at the loading and unloading stations 75 are used to generate the pressure required to transport the liquefied gas.

[0167] The invention applies to ship tanks 71, but also to land-based tanks and harbour structures.

[0168] Although the present invention has been described with reference to several specific embodiments, it is clear that the invention is not limited thereto, but encompasses all technical equivalents and combinations of the described means so long as they fall within the scope of the invention.

[0169] Use of the verb "to include" or "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim.

[0170] In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims

1. A method for manufacturing a metal strip (10), comprising the steps of: - placing an end (13) of a first metal strip element (11) and an end (14) of a second metal strip element (12) on a planar support (21), said end (13) of said first metal strip element (11) and said end (14) of said second metal strip element (12) being longitudinally juxtaposed, each of said first and second metal strip elements (11, 12) having two opposite main faces (11A, 12A) connected by two longitudinal sides (11B, 12B), said first and second metal elements having the same width, said first metal strip element (11) and said end (14) of said second metal strip element (12) being longitudinally juxtaposed, said end (13) of element (11) and said end (14) of said second metal strip element (12) are each terminated by a corresponding lateral end face (11C, 12C), such that the respective main faces (11A, 12A) of said first and second metal strip elements (11, 12) rest at least partially on said planar support (21) and said lateral end face (11C) of said end (13) of said first metal strip element (11) extends adjacent to said lateral end face (12C) of said end (14) of said second metal strip element (12); - aligning said longitudinal sides (11B, 12B) of said first and second metal strip elements (11, 12) so that they extend in a straight line relative to one another; - butt welding said first and second metal strip elements (11, 12) to form a continuous weld along said lateral end faces (11C, 12C) over the entire width of said metal strip elements (11, 12); - cutting the longitudinal edges of the metal strip (10) obtained at least along a region extending in the longitudinal direction of the metal strip (10) from one side of the weld bead to the other side of the weld bead; A method for providing the above.

2. the ends (13, 14) are arranged such that the lateral end face (11C) of the end (13) of the first metal strip element (11) is located at a position extending from the lateral end face (12C) of the end (14) of the second metal strip element (12) by a distance not greater than half the thickness of one of the metal strip elements (11, 12); The method of claim 1.

3. the ends (13, 14) are arranged such that the end (14) of the second metal strip element (12) overlaps the end (13) of the first metal strip element (11) over a distance not greater than three times the thickness of one of the metal strip elements (11, 12); The method of claim 1.

4. - unwinding the roll carrying said first metal strip element (11), The method according to any one of claims 1 to 3.

5. - partially cutting the first metal strip element (11) along the longitudinal side (11B) using two tools (22) arranged on a path for feeding the end (13) of the first metal strip element (11) up to a cutting stop position (AD) located away from the lateral end face (11C) of the first metal strip element (11) intended to be placed in the vicinity of the second metal strip element (12), The method according to any one of claims 1 to 3.

6. The two cutting tools (22) are arranged opposite each other and are not movable. The method according to claim 5.

7. The two cutting tools are disposed opposite each other and are movable in the longitudinal direction. The method according to claim 5.

8. - further comprising the step of winding the cut portion of said first metal strip element (11) around a winding axis perpendicular to said longitudinal direction, The method according to claim 5.

9. Prior to the welding step, portions of the second metal strip element are also cut along the longitudinal sides; the cut portion of the second metal strip element extends from a lateral end face of the second metal strip element to a cut stop position located away from the lateral end face of the second metal strip element intended to be located adjacent to the first metal strip element, The method according to any one of claims 1 to 3.

10. The planar support (21) comprises a metal plate (60); the lateral end faces (11C, 12C) of the first and second metal strip elements (11, 12) arranged adjacent to one another extend facing the metal plate (60) during the welding step; The method according to any one of claims 1 to 3.

11. - pressing the ends (13, 14) of the first and second metal strip elements (11, 12) against the planar support (21) by abutting on both sides of the lateral end faces (11C, 12C) arranged adjacent to one another against the opposite main faces (11A, 12A) of the planar support, The method according to any one of claims 1 to 3.

12. the step of pressing the ends of the first and second metal strip elements (11, 12) against the planar support (21) employs a clamping device (40); the clamping device (40) includes metal abutting portions (41) abutting the main surfaces (11A, 12A) of the metal strip elements (11, 12) on both sides of the lateral end faces of the metal strip elements arranged adjacent to each other, The method of claim 11.

13. - further comprising the step of performing spot welding before generating the continuous weld bead, The method according to any one of claims 1 to 3.

14. The continuous weld bead is produced by a method selected from TIG arc welding, microplasma welding, spallation seam welding, and mastication friction welding. The method according to any one of claims 1 to 3.

15. the cutting stop position (AD) is located at a distance of 1 meter to 3 meters from the lateral end face (11C, 12C) of the cut first or second metal strip element (11, 12); The method according to claim 5.

16. The metal strip elements (11, 12) are made using an alloy of iron and nickel, the coefficient of expansion of which is typically 1×10 －６ Above 2 x 10 －６ K －１ is equal to or less than The metal strip elements are made using an alloy of iron and manganese, the coefficient of expansion of which is 7×10 －６ K －１ Above 9 x 10 －６ K －１ Below is the The method according to any one of claims 1 to 15.

17. Each of the metal strip elements (11, 12) has a thickness of 0.5 to 1 mm. The method according to any one of claims 1 to 16.

18. The method according to any one of the preceding claims, further comprising bending the longitudinal edges of the metal strip (10).

19. A bench for manufacturing metal strip, comprising: a planar support (21) adapted to receive an end (13) of a first metal strip element (11) and an end (14) of a second metal strip element (12), said end of the first metal strip element and said end of the second metal strip element being longitudinally juxtaposed, each of said first and second metal strip elements having two opposite main faces (11A, 12A) connected by two longitudinal sides (11B, 12B), each of said end of the first metal strip element and each of said end of the second metal strip element being terminated by a corresponding lateral end face (11C, 12C), said lateral end face (11C) of said first metal strip element (11) extending in the vicinity of said lateral end face (12C) of said second metal strip element (12); an alignment device (30) for aligning the relative positions of the longitudinal sides of said first and second metal strip elements so that they extend in line with one another; a working gantry (50) for butt-welding said two metal strip elements with a continuous weld bead extending along said lateral end faces over the entire length of said metal strip elements; - two cutting tools adapted to cut the longitudinal edges of the metal strip (10) obtained at least along an area extending in the longitudinal direction of the metal strip (10) from one side of the weld bead to the other side of the weld bead; A bench equipped with

20. A metal strake suitable for manufacturing a sealing membrane for a sealed insulated tank, comprising: A metal strip (10) obtained by the method according to any one of claims 1 to 3 from two metal strip elements (11, 12) each having a constant thickness over its entire length, 1. A metal strake having in its width direction a planar central portion and two lateral limbs bent substantially perpendicularly to said planar central portion, said two lateral limbs having a small width compared to said planar central portion.

21. A sealing membrane for a sealed insulated tank, comprising: A repeating structure including alternating metal strakes according to claim 20 and elongated weld flanges connected to a support surface of the sealing membrane and projecting relative to the sealing membrane. Equipped with the weld flange extends parallel to the metal strake for at least a portion of the length of the metal strake; the planar central portion of the metal strake is placed on the support surface and the lateral edges of the metal strake are placed against the adjacent weld flanges and hermetically welded to the weld flanges; Sealing membrane.

22. 1. A sealed, insulated tank integrated into a support structure, comprising: the support structure includes a plurality of support walls; the tank includes a plurality of tank walls, each of which is secured to a corresponding one of the support walls; the tank wall includes an insulating barrier supported on the support wall; The insulating barrier comprises a planar support surface parallel to the corresponding support wall and a sealing membrane according to claim 21. Sealed insulated tank.

23. A vessel (70) for transporting a fluid, comprising: Double hull (72) and A tank (71) according to claim 22, arranged within the double hull (72); A ship equipped with.

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