KR20240038593A - Anchoring strip and method for manufacturing such an anchoring strip - Google Patents

Abstract

The present invention relates to a fixing strip (20), wherein the fixing strip (20)
- a lower surface (21) extending in the first plane (P1),
- on the first plane P1 along an axis Z extending in a second plane P2 generally parallel to the first plane P1 and generally perpendicular to the first plane P1 and the second plane P2. a disposed upper surface (22);
- passes through the fixing strip between a first orifice (24) and a second orifice (25), which extends around the axis (Z) and is arranged in a second plane (P2), at least one through hole (23) of increasing cross-section between the first orifice (24) and the intermediate orifice (26) disposed between the orifices (25);
Including,
The fixing strip is such that the second orifice 25 lies in a third plane P3 generally parallel to the first plane P1 and the second plane P2, with the third plane P3 being aligned with the axis Z. It is characterized in that it is arranged below the second plane (P2).

Description

Fixing strip and method of manufacturing such fixing strip {ANCHORING STRIP AND METHOD FOR MANUFACTURING SUCH AN ANCHORING STRIP}

The present invention relates to a retaining strip and a manufacturing method for manufacturing the retaining strip.

The fastening strip is particularly intended for use in sealed, insulated tanks for transporting and/or storing liquefied gases.

Hereinafter it is customary to use the terms “external” and “internal” to determine the relative position of one element with respect to the inside and outside of the tank.

Each tank wall has at least one sealing membrane, an insulating barrier and a load-bearing structure disposed continuously in the thickness direction from the inside of the tank to the outside of the tank, in contact with the fluid contained in the tank. Alternatively, the wall may also include two levels of sealing and insulation.

Figure 1 shows an insulating panel 1 designed for sealed insulated tanks known from the prior art. In this case, the panel 1 is generally rectangular. The panel comprises a layer of insulating packing (2) sandwiched between a rigid inner plate (3) and a rigid outer plate (4). The rigid inner plate (3) and the outer rigid outer plate (4) are for example plywood plates bonded to the insulating packing (2) layer. The insulating packing layer may be an insulating polymer foam, especially a polyurethane-based foam. Polymer foams can advantageously be reinforced using glass fibres, thereby helping to reduce heat shrinkage. The panel 1 may have a shape other than a rectangular parallelepiped.

For example, the panel 1 is 3 meters long and 1 meter wide. The plywood inner plate 3 may be 12 mm thick, the plywood outer plate 4 may be 9 mm thick and the insulating packing layer 2 may be 200 mm thick. Naturally, the above dimensions and thicknesses are provided as a reference and will vary depending on the intended use and required thermal insulation performance. Additionally, other insulating materials may form the insulating packing of the panel.

The inner surface of the panel 1 includes fastening strips or metal plates 5, 6 for fixing the metal plate 7 (an example of which is shown in Figure 2) forming a sealing membrane. For example, the fastening strips 5 extend longitudinally along the inner plate 3 of the panel 1 and the fastening strips 6 extend transversely. The fastening strips 5, 6 are usually riveted to the inner plate 3 of the panel 1. The fastening strips 5, 6 can in particular be made of stainless steel or Invar ^® , an iron-nickel alloy whose main property is a very low coefficient of expansion. The thickness of the fixing strips 5 and 6 of the prior art is, for example, about 2 mm. The metal plate 7 is fixed to the fixing strips 5, 6 by intermittent welding. The fastening strips 5, 6 are therefore usually riveted to the panel 1. The metal plate 7 is welded to the fastening strip, thereby securing the metal plate 7 to the panel 1.

The sealing membrane is obtained by assembling a number of metal plates 7 welded together along their edges. The metal plate (7) generally comprises a series of first parallel corrugations, called low corrugations (8), extending in the y-direction and a series of second parallel corrugations, called high corrugations (9), extending in the x-direction. there is. The x and y directions of the series of wrinkles (8, 9) are perpendicular. The wrinkles 8 and 9 protrude from the inner surface of the metal plate 7. The edge of the metal plate 7 is in this case parallel to the corrugations 8, 9. The metal plate 7 has a plurality of flat surfaces 11 between the corrugations 8 and 9. The expressions “high” and “low” are relative and mean that the first series of pleats (8) is not as high as the second series of pleats (9). At the intersection (10) between the low corrugation (8) and the high corrugation (9), the low corrugation is discontinuous. In other words, it is interrupted by a fold extending the upper edge of the higher pleats (9) which protrude above the upper edge of the lower pleats (8). The corrugations 8, 9 provide considerable flexibility and allow the sealing membrane to be deformed under the influence of stresses generated by the (very low temperature) fluid stored in the tank, especially thermal stresses.

The metal plate 7 is made of a stainless steel or aluminum plate formed by bending or drawing. Other metals and alloys may also be used. For example, the metal plate 7 has a thickness of approximately 1.2 mm. Other thicknesses are possible, and it should be borne in mind that thickening the metal plate (7) increases the cost and generally increases the stiffness of the corrugation.

A metal plate (7) is placed on the insulating panel (1). The metal plates 7 can be arranged, for example, by half the length and half the width with respect to the insulating panel 1 . The wall may therefore comprise a plurality of insulating panels 1 and a plurality of metal plates 7 , each of which extends over four adjacent insulating panels 1 .

One of the longitudinal edges 12 of the metal plate 7 is fixed to the insulation panel 1 by welding the longitudinal edge 12 to the fastening strip 5. Likewise, one of the transverse edges 13 is fixed to the insulation panel 1 by welding the transverse edge 13 to the fixing strip 6. The fastening zones between the metal plate (7) and the insulation panel (1) are arranged on both sides of the corrugations (8, 9). In other words, the fixing zone is formed at the interface between the fixing strips 5, 6 and the flat portions 11 of the edges 12, 13 of the metal plate 7 extending on both sides of the corrugations 8, 9. .

Fixing strips 5, 6 are placed in slots of the panel 1 in a generally rigid inner plate 3 (usually a plywood plate). Each fastening strip is fastened to a rigid inner plate by at least one rivet. Typically, the fastening strip has two through holes which make it possible to fasten it to the panel with two rivets.

Figure 3 is a cross-sectional view of the assembly of the fastening strips 5 to the panel 1 (i.e. to the plate 3) using rivets 14 as in the prior art. Through holes in the fastening strip to receive the rivets are formed by piercing or machining. Typically, the fastening strip includes two through holes each for receiving a rivet for fastening the fastening strip to the panel 1.

The cross section in Figure 3 shows that once placed the rivets do not protrude beyond the fastening strips 5, which are placed in slots in the panel 1. The top of the rivet 14 is arranged at a distance d from the upper surface of the fastening strip. In other words, the shape of the rivet allows it to be positioned below the fastening strip. Rivets are thus integrated into the panel (1). This assembly therefore has no protrusions that could damage the sealing membrane in terms of positioning and possibly scratching.

Although overall satisfactory, this solution has one drawback: the rivets 14 make conical contact with the fastening strips 5 and the top of the panel. As a result, the assembly of fastening strips and rivets is subjected to excessive stresses due to the geometry of the assembly: conical-conical contact and precise placement of the rivets in the through holes. As a result, the assembly is not properly controlled. This may cause assembly defects. For example, this assembly geometry can lead to rivet extrusion issues, especially if rivets are misplaced due to manufacturing tolerances.

The present invention seeks to overcome some or all of the above problems by proposing a novel anchoring strip geometry that allows integration of different types of rivets. The proposed fixing strip ensures easy assembly without excessive geometrical stress.

For this purpose, the invention relates to a fastening strip, said fastening strip comprising:

- a lower surface extending in a first plane,

- an upper surface extending in a second plane generally parallel to the first plane and disposed above the first plane along an axis generally perpendicular to the first and second planes,

- extends around said axis and passes through said fixing strip between a first orifice and a second orifice arranged in a second plane, and has a cross-section between the first orifice and an intermediate orifice arranged between the first and second orifices. at least one increasing through hole,

Including,

The securing strip is characterized in that the second orifice lies in a third plane generally parallel to the first and second planes, and the third plane is arranged below the second plane along the axis.

Advantageously, said at least one through hole has a generally constant cross-section between the second orifice and the intermediate orifice.

In one embodiment, the retaining strip according to the invention further comprises a bearing surface generally perpendicular to the axis and extending around the perimeter of the intermediate orifice.

Advantageously, the support surface is arranged at a distance from the upper surface, the distance being preferably greater than 0.7 mm, more preferably greater than 2 mm.

In one embodiment, the intermediate orifice is in the first plane.

Advantageously, the fastening strip according to the invention is made of metal, preferably stainless steel.

The invention also relates to a method for manufacturing such fastening strips, comprising the following steps:

- supplying strips,

And, simultaneously or sequentially in any order:

- a piercing step of piercing the strip along said axis using a piercing punch to form at least one through hole,

- a drawing step in which the strip is drawn into a cone using a drawing punch with a conical tip,

It includes.

In one embodiment of the method according to the invention, the drawing step comprises forming a support surface that is generally perpendicular to the axis and extends around the perimeter of the intermediate orifice.

In one embodiment of the present invention, the manufacturing method according to the present invention may further include cutting the strip to obtain a fixing strip.

In one embodiment of the invention, the drawing step is performed after the piercing step.

In one embodiment of the invention, the piercing and drawing steps of the method are performed sequentially at two different stations: a first station comprising a piercing punch and a first die and a second station comprising a drawing punch and a second die. It contains a die, and at each step there is a transfer operation from one station to the next.

In another embodiment of the invention, the piercing and drawing steps of the method are performed continuously at the same station containing punch and die tools, changing the punch at each step.

The present invention also relates to a wall for a sealed and insulated storage tank for liquefied gas, the wall being continuous in the thickness direction from the outside to the inside.

- at least one insulating panel designed to be supported directly or indirectly on a load-bearing structure,

- a sealing membrane supported on the insulating panel and brought into contact with the liquefied gas contained in the tank,

Including,

The insulation panel comprises at least one fastening zone on which the fastening strip according to the invention is disposed, the at least one fastening zone conforming to the shape of the fastening strip rigidly fixed to the heat insulating panel, and the sealing membrane It is secured to the upper surface of at least one fastening strip.

The invention also relates to a sealed insulated tank on board a ship for containing liquefied gas comprising at least one such wall.

Finally, the invention also relates to a ship comprising a hull forming a load-bearing structure and these tanks fixed to said load-bearing structure.

The invention also relates to a computer program comprising computer-executable instructions that, when executed by the processor, cause the processor to control an additive manufacturing device to manufacture a retaining strip as described above.

As an alternative to the above-described method, the present invention also relates to a method for manufacturing fastening strips by additive manufacturing, said method comprising:

- obtaining an electronic file showing the geometry of said fastening strip, and

- controlling an additive manufacturing device to manufacture, in one or more additive manufacturing steps, a fastening strip according to the geometry specified in the electronic file,

Includes.

As used herein, the term "additive manufacturing" generally refers to a manufacturing process in which successive layers of material(s) are placed on top of each other to "stack" layer by layer, or to "stack" a fastening strip. it means.

This may be compared to a stock-removal manufacturing method (eg, milling or drilling) in which material is continuously removed to produce a retaining strip. Successive layers are typically fused together to form an integral component that may include various integrated subcomponents.

In particular, the above manufacturing method can form the fixing strip as an integrated piece, and can have more diverse features than when using previous manufacturing methods.

Significant changes can be made to the characteristics of the retaining strip, for example, changes in the flared portion between the intermediate orifice and the first orifice, which may be difficult to achieve with conventional manufacturing techniques.

A common example of additive manufacturing is 3D printing. However, other additive manufacturing methods can be used.

The terms rapid prototyping or rapid manufacturing are also terms that can be used to describe additive manufacturing methods.

Additive manufacturing makes it possible to manufacture materials of any suitable size and shape with a variety of characteristics that may not be possible with previous manufacturing methods.

Additive manufacturing can create complex geometries without using tools, molds or fixtures of any kind and with little or no waste. When machining fastening strips from metal coils, a portion of the metal coils is cut/machined and discarded, whereas in additive manufacturing the only materials used are those needed to form the part. Accordingly, fastening strips can be manufactured for specific applications. In other words, the fixing strip can be manufactured to suit a specific environment.

Suitable additive manufacturing techniques according to the invention include, for example, fused deposition modeling (FDM), selective laser sintering (SLS), 3D printing such as inkjet and laserjet, stereolithography (SLA), direct selective laser sintering (DSLS), Electron beam sintering (EBS), electron beam melting (EBM), laser engineered net shaping (LENS), electron beam additive manufacturing (EBAM), laser net shape manufacturing (LNSM), and direct metal deposition (DMD). ), digital light processing (DLP), continuous digital light processing (CDLP), direct selective laser melting (DSLM), selective laser melting (SLM), direct metal laser melting (DMLM), direct metal laser sintering (DMLS), material jetting. (MJ), nanoparticle jetting (NPJ), drop on demand (DOD), binder jetting (BJ), multi jet fusion (MJF), laminated object manufacturing ( LOM: laminated object manufacturing) and other known methods.

The additive manufacturing methods described herein can be used to form components using any suitable material.

For example, the material may be a plastic, metal, composite, ceramic, polymer, epoxy or any other suitable material that may be in a solid, liquid, powder, sheet, wire or other form.

More specifically, the fastening strips described herein may be pure metal, nickel alloy, chromium alloy, titanium, titanium alloy, magnesium, magnesium alloy, aluminum, aluminum alloy, iron, iron alloy, stainless steel and nickel or cobalt based. It may be formed in part, in whole or in combination, of materials including, but not limited to, superalloys (e.g., sold under the name ^Inconel® by Special Metals Corporation). These materials are examples of materials suitable for use in additive manufacturing processes that may be suitable for manufacturing the fastening strips described herein. Preferably stainless steel is used in instances where it is used as fastening strips for sealing membranes on plywood panels.

As noted above, the additive manufacturing methods described herein allow a single component, such as a fastening strip, to be formed from multiple materials.

Accordingly, the fastening strips described herein may be formed from any suitable combination of the materials described above. For example, a component may include multiple layers, segments, or parts formed using various materials, methods, and/or various additive manufacturing machines. Therefore, components can be manufactured from a variety of materials and material properties to meet the requirements of specific applications.

Forming fastening strips by additive manufacturing reduces waste compared to conventional material removal manufacturing techniques or machining processes that cut parts from larger blocks of material.

The structure of the product (fixing strip) can be represented digitally in the form of a design file.

A design file or computer-aided design (CAD) file is a configuration file that encodes one or more of the surface configuration or volume configuration of the shape of a product. In other words, a design file represents the geometric layout or shape of the product.

Design files can be in existing or future file formats. For example, the design file may be in the "standard tessellation language" (.stl) format developed for the Stereolithography or Stereolithography CAD programs from 3D Systems, or in the "standard tessellation language" (.stl) format developed for the Stereolithography CAD program by any CAD software. Additive manufacturing file (.amf) from the American Society of Mechanical Engineers (ASME), a format based on Extensible Markup Language (XML) designed to describe the shape and configuration of arbitrary three-dimensional objects to be manufactured by an additive manufacturing printer. It can be in the form

Other examples of design file formats include AutoCAD files (.dwg), Blender files (.blend), Parasolid files (.x_t), 3D Manufacturing Format files (.3mf), Autodesk files (3ds), Collada files (.dae), and Includes Wavefront files (.obj), but many other file formats exist.

The design file may be created using modeling (e.g., CAD modeling) and/or scanning the surface of the product to determine its surface layout.

Once the design file is obtained, the design file can be converted into a series of computer-executable instructions that, when executed by a processor, cause the processor to control the additive manufacturing device to produce the product according to the geometric layout specified in the design file.

Conversion allows design files to be converted into slices or layers to be sequentially formed by an additive manufacturing device.

Instructions (also called geometric codes or “G-codes”) can be calibrated for a specific additive manufacturing device and can specify the exact location and amount of material to be formed at each step of the manufacturing process.

As noted above, formation may be performed by deposition, sintering, or any other form of additive manufacturing method.

The code or command may be translated, if necessary, between different formats, converted to a set of data signals and transmitted, received as a set of data signals, converted to code, and stored.

Commands may be input to the additive manufacturing system and may come from a part designer, intellectual property provider, design firm, operator or owner of the additive manufacturing system, or other sources.

An additive manufacturing system can execute instructions to manufacture a product using the techniques or methods described herein.

The design file or computer executable instructions may be stored in a computer-readable storage medium (transitory or non-transitory) (e.g., memory, storage system, etc.) that stores computer-readable code or instructions representing the product to be manufactured. there is.

As noted above, computer-readable code or instructions that define a product may be used to physically create an object when the code or instructions are executed by an additive manufacturing system.

For example, the instructions may include a precisely defined 3D model of the product and may be generated from a variety of well-known computer-aided design (CAD) software systems, such as ^AutoCAD® , ^TurboCAD® , DesignCAD 3D Max, etc.

Alternatively, a model or prototype of the component can be scanned to obtain three-dimensional data about the component.

Accordingly, an additive manufacturing device can be instructed to print a product by controlling the additive manufacturing device with computer-executable instructions.

In light of the above, embodiments of the present invention include manufacturing methods using additive manufacturing.

This includes obtaining a design file representing the product and instructing the additive manufacturing device to manufacture the product in assembled or unassembled form according to the design file.

The additive manufacturing device may have a processor configured to automatically convert the design file into computer-executable instructions to control manufacturing of the product.

In this embodiment, the design file can be entered into an additive manufacturing device and automatically cause the product to be manufactured.

Accordingly, in this embodiment, a design file can be considered computer-executable instructions that cause an additive manufacturing device to manufacture a product.

Alternatively, the design file may be converted to instructions by an external computer system, resulting in computer-executable instructions being supplied to the additive manufacturing device.

In view of the foregoing, the design and manufacture of objects utilizing the methods according to the invention and the operations described herein may not utilize digital electronic circuitry, computer software, firmware or the structures described herein and their structural equivalents. This can be achieved using hardware comprising: or a combination of one or more of the above.

For example, the hardware may include a processor, microprocessor, electronic circuit, electronic component, integrated circuit, etc.

An object may use a method according to the subject matter of the invention using one or more computer programs, i.e. one or more computer program instruction modules, encoded on a computer storage medium for execution by a data processing device or to control the operation of the data processing device. It can be made using

Alternatively or additionally, the program instructions may be propagated by an artificially generated radio signal, such as a machine-generated electrical signal, an optical signal, or an electromagnetic signal, which is generated to encode information to be transmitted to an appropriate receiving device for execution by a data processing device. signal).

A computer storage medium may be or include a computer-readable storage device, a computer-readable storage substrate, a random access or serial memory array or device, or a combination of one or more thereof.

Additionally, although the computer storage medium is not a radio signal, the computer storage medium may be a source or destination of computer program instructions encoded with artificially generated radio signals.

Computer storage media may also be or include one or more individual components or physical media (eg, several CDs, disks, or other storage devices).

Although additive manufacturing techniques are described herein as enabling the manufacture of complex objects by stacking the objects layer by layer, generally in a vertical direction, other manufacturing methods are possible and fall within the scope of the present invention.

For example, although the description herein describes stacking materials to form continuous layers, those skilled in the art will recognize that the methods and structures described herein can be implemented with any additive manufacturing technique or other manufacturing technique. You will be able to find out.

Embodiments of the invention described may include one or more examples, embodiments, or features individually or in various combinations, whether or not specifically described (or claimed), in any combination.

These and other features and advantages of the present invention will become more apparent from the following description given by way of non-limiting example and in conjunction with the accompanying drawings.
Figure 1 shows an insulating panel 1 designed for a sealed insulated tank known from the prior art,
Figure 2 shows an example of a metal plate forming a sealing membrane in the prior art;
Figure 3 is a cross-sectional view of an assembly in which a fixing strip is assembled to a panel using rivets as in the prior art;
Figure 4 is a cross-sectional view of a first embodiment of the fixing strip according to the invention;
Figure 5 shows a second embodiment of the fixing strip according to the invention,
Figure 6 is a cross-sectional view of a second embodiment of the fixing strip according to the invention;
Figure 7 is a cross-sectional view of a third embodiment of the fixing strip according to the invention;
Figure 8 is a cross-sectional view of an assembly in which a fixing strip according to the present invention is assembled to a panel portion;
Figure 9 schematically shows the manufacturing method of the fixing strip according to the present invention.

For clarity, like elements are indicated by like reference numerals in all drawings.

Figure 1 shows an insulating panel 1 designed for sealed insulated tanks known from the prior art. This drawing has already been described above.

Figure 2 shows an example of a metal plate forming a sealing membrane in the prior art, as described above.

Figure 3 is a cross-sectional view of an assembly in which fixing strips are assembled to a panel using rivets as in the prior art. This drawing has already been described above.

Hereinafter, the term "anchoring strip", also known as anchoring plate, refers to an anchoring strip disposed in a panel, preferably in a dedicated slot in the panel corresponding to the shape of the anchoring strip, and attaching the strip to the panel. Refers to a strip fixed to the panel to ensure a firm connection. The fastening strips form the fastening supports and fasten the sealing membrane to the panel, usually by welding.

Figure 4 is a cross-sectional view of a first embodiment of the fixing strip 20 according to the invention. The fastening strip 20 comprises a lower surface 21 extending in a first plane P1. The terms “lower” and “upper” refer to the relative position of one element relative to another, along an axis perpendicular to the lower surface 21. The fastening strip 20 extends in a second plane P2 generally parallel to the first plane P1 and has a first axis along an axis Z generally perpendicular to the first plane P1 and the second plane P2. It includes an upper surface 22 disposed on a plane P1. In other words, moving along axis Z in the direction shown in Figure 4, the upper surface 22 is positioned above the lower surface 21.

The fastening strip 20 extends around the axis Z and has at least one through hole 23 passing through the fastening strip between the first orifice 24 and the second orifice 25 arranged in the second plane P2. ), wherein the at least one through hole 23 has an increased cross-section between the first orifice 24 and the intermediate orifice 26 disposed between the first orifice 24 and the second orifice 25. do. In other words, the through hole 23 has a flared shape from the middle orifice toward the first orifice.

According to the invention, the second orifice 25 lies in a third plane P3 generally parallel to the first plane P1 and the second plane P2, the third plane P3 being along the axis Z. It is arranged below the second plane (P2). In other words, the fastening strip mainly extends between the lower surface 21 and the upper surface 22 of the fastening strip and has a protrusion extending below the lower surface 21 at the through hole 23.

The fastening strip according to the invention advantageously comprises two through holes 23 spaced apart from each other, as shown in FIG. 5 .

It should be noted that the fastening strips 20 are fastened to the associated panels by rivets placed in the respective through holes 23. The panel (or panel slot) is therefore positioned below the fastening strip 20 and in contact with the lower surface 21 . A rivet is placed in the through hole (23). The flared portion between the middle orifice 26 and the first orifice 24 is designed to receive the rivet head to prevent the rivet head from protruding. The present invention is described using a rivet as an example. The same principle applies to other fastening elements with heads, such as screws.

The specific geometry of the fastening strip according to the invention with protrusions below the lower surface allows the fastening strip to come into contact with the panel so that the fastening strip 20 can be riveted to the panel. Additionally, the rivet head does not make conical-conical contact with the panel-anchoring strip assembly. This fixed strip layout allows new assembly methods that were not previously feasible.

Figure 5 shows a second embodiment of the fixing strip 30 according to the invention. As shown, the fastening strip preferably comprises two through holes 23. This second embodiment is described in detail below.

Figure 6 is a cross-sectional view of a second embodiment of the fixing strip 30 according to the invention. This fixing strip 30 is the same as the fixing strip 20 described above. The fastening strip 30 also includes a support surface 31 generally perpendicular to the axis Z, extending around the perimeter 32 of the intermediate orifice 26.

The support surface 31 provides a support surface for the head of a fastening element such as a rivet or screw. The advantage of providing a support surface 31 around the intermediate orifice is that the positioning function can be separated from the support function. This will prevent excessive stress from being applied to the part. Additionally, other types of fastening elements can be used to fasten the fastening strips to the panel.

Advantageously, the support surface is arranged at a distance from the top surface 22, and the distance between the support surface and the top surface 22 is preferably at least 0.7 mm, or at least 1 mm, more preferably at least 2 mm. This distance ensures that the rivet head is fully integrated into the retaining strip in a fixed position. The rivets do not extend beyond the top surface 22. This will ensure that there are no protrusions that could damage the sealing membrane.

In the figures provided, at least one through hole 23 has a generally constant cross-section between the second orifice 25 and the intermediate orifice 26. This portion of the through hole 23 is designed to receive the shank of a rivet. However, although less advantageous from an industrial point of view, this part of the fastening strip according to the invention may have a variable cross-section.

Figure 7 is a cross-sectional view of a third embodiment of the fixing strip 40 according to the present invention. This fixing strip is the same as the fixing strip 30 described above. In the embodiment of the fastening strip 40 shown in Figure 7, the intermediate orifice 26 is arranged in the first plane. Therefore, in this layout, the distance between the top surface 22 and the support surface 31 corresponds to the main thickness of the fastening strip. This feature makes it easy to manage the protrusion of the rivet head. In practice, the thickness of the fastening strip can be used to determine the maximum permissible height of the rivet head, i.e. so that it does not extend beyond the top surface 22.

Advantageously, the fastening strip according to the invention is made of metal, preferably stainless steel. However, other metals suitable for the purpose of use of the fastening strip (welding to metal membranes) can also be used. For example, the fastening strips may be made of Invar ^® (an iron-nickel alloy with a low coefficient of expansion).

Figure 8 is a cross-sectional view of an assembly 50 of fastening strips 40 according to the invention on a part of a panel 1. The fastening strips according to the invention are placed in slots of the panel 1 provided for this purpose. The slot in the panel 1 thus has a surface that matches the shape of the lower surface 21 of the fastening strip 40 and the lower protrusion. The contact area between the fastening strip and the slot in the panel is marked with reference numeral 52. When fastening the fastening strip 40 to the panel 1, rivets (not shown) are placed in the through holes 23. More specifically, the shank of the rivet slides into a through hole 23 in the fastening strip 40 and into a through hole in the panel 1 aligned with the through hole 23. This assembly allows for manufacturing tolerances unlike the prior art (see Figure 3) due to the presence of clearances. This optimizes the rivet-anchoring strip assembly, meeting assembly standards more efficiently.

Figure 9 schematically shows a method for manufacturing a fastening strip according to the invention. The method of manufacturing the fastening strips involves the following steps:

- a lower surface 21 extending in a first plane P1 and extending in a second plane P2 generally parallel to the first plane P1 and in the first plane P1 and the second plane P2. supplying a strip comprising an upper surface (22) disposed on a first plane (P1) along a generally vertical axis (Z) (step 100);

And, simultaneously or sequentially in any order:

- piercing to form at least one (preferably two) through holes 23 passing through the fastening strip between the first orifice 24 and the second orifice 25 arranged in the second plane P2. a piercing step (step 110) wherein a punch (typically a drill) is used to pierce the strip along the Z-axis;

- at least one through hole (23) increases in cross-section towards the first orifice (24) from the intermediate orifice (26) arranged between the first orifice (24) and the second orifice, and the second orifice (25) The strip is formed using a drawing punch with a conical tip so that it lies in a third plane (P3) that is generally parallel to the first plane (P1) and the second plane (P2) and located below the second plane (P2) along the Z-axis. A drawing step of drawing into a cone (step 120),

Includes.

Preferably, step 110 and step 120 are performed simultaneously, and the piercing step is performed by drawing. In other words, only one press step is required to create the through hole and bottom protrusion of the fastening strip.

The manufacturing method according to the invention by piercing and drawing produces a lower projection of the fastening strip. Moreover, the material of the fastening strip is not usually processed by milling but is deformed during manufacturing. This manufacturing method does not generate chips. Additionally, since it does not involve milling, no lubrication is required. Another advantage of not requiring lubrication is that it eliminates the need for special cleaning, which is typically done using various chemicals and ultrasonic baths.

Finally, the use of controlled punches increases quality levels. This helps control maintenance and reduce quality control requirements.

In another embodiment of the manufacturing method according to the invention, the drawing step 120 comprises a step 125 for forming a support surface 31 generally perpendicular to axis Z extending around the perimeter 32 of the intermediate orifice 26. . In this embodiment, the tip of the punch used is shaped like a cone and its top is cut flat. In other words, the tip of the used punch is shaped like a truncated cone.

If the strip is supplied in coil form in step 100, the manufacturing method according to the present invention also includes a cutting step 130 of cutting the strip. This cutting step 130 may occur before or after the piercing step 110, or before or after the drawing step 120. This cutting step 130 provides the fastening strip with an appropriate length and width.

If the strip is supplied in coil form in step 100, the method may optionally include flattening the coil to obtain a plate of desired thickness.

In one embodiment of the manufacturing method according to the invention, the drawing step 120 is performed after the piercing step 110.

In one embodiment of the manufacturing method according to the invention, the piercing and drawing steps 110, 120 of the method are carried out sequentially in two different stations: a first station comprising a piercing punch and a first die; The second station contains a drawing punch and a second die, and at each step there is a transfer operation from one station to the next. For example, referring to Figure 5, a piercing step is performed to form hole 23 (zone A). At this stage, Zone B has not yet been processed. The retaining strip is then moved to allow drilling of the second hole 23 (zone B). Zone A, further along the line, can now undergo the drawing phase.

In an alternative embodiment of the manufacturing method according to the invention, the piercing and drawing steps 110, 120 of the method are performed continuously at the same station comprising punch and die tools, changing the punch at each step.

Each time the tool moves (preferably vertically), the retaining strip moves by the amount corresponding to one tool. For example, referring to Figure 5, a piercing step is performed to form hole 23 (zone A). At this stage, Zone B has not yet been processed. A drawing step is then performed in the hole 23 in zone A by performing a tool change (from piercing punch to drawing punch). A piercing step is then performed by moving the fixing strip to form a hole 23 in area B, etc. Alternatively, the fixing strip can remain fixed and the tool moves from zone A to zone B. If necessary, this may include cutting of the coil using the same principles. This allows one machine to perform all steps simultaneously.

This new manufacturing method according to the invention can help to significantly reduce the cost of fastening strips. In practice, the production speed is reduced from approximately 10 seconds (excluding the wash bath) to approximately 3 seconds per holding strip (with 2 or 8 through holes, depending on the mold used). The direct result is a reduction in production costs. Additionally, as explained above, different types of rivets are suitable for fastening strips according to the invention, allowing a wider variety of rivet suppliers to be used.

The present invention also relates to a wall for a sealed and insulated storage tank for liquefied gas, the wall being continuous in the thickness direction from the outside to the inside.

- at least one insulating panel (1) designed to be directly or indirectly supported on a load-bearing structure,

- a sealing membrane (7) supported on the insulating panel (1) and brought into contact with the liquefied gas contained in the tank,

Including,

The insulating panel 1 includes at least one fixing zone 52 in which the fixing strips are disposed, and the at least one fixing area 52 is one of the fixing strips firmly fixed to the insulating panel 1. conforms to the shape, and the sealing membrane 7 is fixed to the upper surface 22 of at least one fastening strip.

The invention also relates to a sealed insulated tank on board a ship for containing liquefied gas comprising at least one wall as described above.

Finally, the invention relates to a ship comprising a hull forming a load-bearing structure and such tanks fixed to the load-bearing structure.

It will be more generally apparent to those skilled in the art, in light of the above disclosure, that various modifications may be made to the above-described embodiments. In the claims below, the terminology used should not be construed as limiting the claims to the embodiments described herein, but rather includes all equivalents that the claim language is intended to encompass and that come within the common knowledge of those skilled in the art. It should be interpreted as

Claims (8)

A wall for a sealed and insulated storage tank for liquefied gas, arranged continuously in the thickness direction from the outside to the inside.
- at least one insulating panel (1) designed to be directly or indirectly supported on a load-bearing structure,
- a sealing membrane (7) supported on the insulating panel (1) and brought into contact with the liquefied gas contained in the tank,
Including,
The insulating panel (1) includes at least one fastening zone (52) in which fastening strips (20, 30, 40) are arranged,
The fixing strip is
- a lower surface (21) extending in the first plane (P1),
- on the first plane P1 along an axis Z extending in a second plane P2 generally parallel to the first plane P1 and generally perpendicular to the first plane P1 and the second plane P2. a disposed upper surface (22);
- passes through the fixing strip between a first orifice (24) and a second orifice (25), which extends around the axis (Z) and is arranged in a second plane (P2), at least one through hole (23) of increasing cross-section between the first orifice (24) and the intermediate orifice (26) disposed between the orifices (25);
Including,
The second orifice 25 lies in a third plane P3 generally parallel to the first plane P1 and the second plane P2, the third plane P3 being in the second plane along the axis Z. arranged below the plane P2, wherein the at least one fastening zone 52 corresponds to the shape of the fastening strips 20, 30, 40 rigidly fixed to the insulating panel 1, and the sealing membrane ( 7) A wall for a sealed and insulated storage tank for liquefied gas, characterized in that the at least one fastening strip (20, 30, 40) is fixed to the upper surface (22). 2. Wall for a sealed insulated storage tank for liquefied gas according to claim 1, characterized in that the at least one through hole (23) has a substantially constant cross-section between the second orifice (25) and the intermediate orifice (26). 3. Use according to claim 1 or 2, further comprising a support surface (31) generally perpendicular to the axis (Z) extending around the circumference (32) of the intermediate orifice (26). Walls for sealed insulated storage tanks. 4. Sealed insulated storage for liquefied gas according to claim 3, characterized in that the support surface is arranged at a distance from the upper surface (22), the distance being preferably at least 0.7 mm, more preferably at least 2 mm. Wall for tank. 5. The wall of any one of claims 1 to 4, wherein the intermediate orifice is in the first plane. 6. A wall for a sealed and insulated storage tank for liquefied gas according to any one of claims 1 to 5, characterized in that it is made of metal, preferably stainless steel. A sealed and insulated tank on a ship for accommodating liquefied gas, comprising at least one wall according to any one of claims 1 to 6. A vessel comprising a hull forming a load-bearing structure and a tank according to claim 7 fixed to the load-bearing structure.