CN114616078A

CN114616078A - Apparatus and method for manufacturing corner structure of sealed and thermally insulated tank

Info

Publication number: CN114616078A
Application number: CN202080075380.9A
Authority: CN
Inventors: 迈克尔·埃里; 纪尧姆·萨尔蒙·勒加尼厄; 皮埃里克·吉尔曼
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2019-10-25
Filing date: 2020-10-22
Publication date: 2022-06-10
Also published as: FR3102533A1; KR20220088484A; WO2021078869A3; WO2021078869A2; FR3102533B1

Abstract

The invention relates to a method for producing a tank construction element (1), comprising the following steps: -providing a secondary insulation structure (2) comprising a support face, -providing a plurality of primary insulation blocks (3), -interposing a spacer (21) between a first primary insulation block of the plurality of primary insulation blocks (3) and a second primary insulation block of the plurality of primary insulation blocks (3) such that the spacer (21) maintains a predetermined spacing between the first primary insulation block and the second primary insulation block, -fixing the primary insulation blocks to the support surface of the secondary insulation structure (2), the maintaining spacer (21) being interposed between the first primary insulation block and the second primary insulation block so as to maintain the predetermined spacing between the first primary insulation block and the second primary insulation block when the first primary insulation block and the second primary insulation block are fixed.

Description

Apparatus and method for manufacturing corner structure of sealed and thermally insulated tank

Technical Field

The present invention relates to the field of sealed and thermally insulating cans with a film. In particular, the present invention relates to the field of sealed and thermally insulated tanks for storing and/or transporting liquefied gases at low temperatures, such as tanks for transporting liquefied petroleum gas (also called LPG) having a temperature for example comprised between-50 ℃ and 0 ℃, or for transporting Liquefied Natural Gas (LNG) at atmospheric pressure at about-162 ℃. These tanks may be installed onshore or on a floating structure. In the case of a floating structure, the tank may be used to transport liquefied gas or to receive liquefied gas for use as a fuel to propel the floating structure.

In one embodiment, the liquefied gas is LNG, i.e. a mixture with a high methane content stored at atmospheric pressure at a temperature of about-162 ℃. Other liquefied gases, in particular ethane, propane, butane or ethylene, are also conceivable. It is also possible to store the liquefied gas under pressure, for example at a relative pressure of between 2bar and 20bar, in particular at a relative pressure of approximately 2 bar. The tank can be produced according to different techniques, in particular in the form of an integrated tank with membrane or a self-supporting tank.

Background

Document FR2691520 discloses a corner structure of a sealed and thermally insulating can. The corner structure includes a secondary corner structure formed by a secondary thermal insulation barrier and a secondary sealing film. The corner structure also includes a plurality of primary insulating blocks secured in juxtaposition to the secondary corner structure. Each of the primary thermal insulation blocks comprises a primary thermal insulation barrier portion to which corner portions are anchored.

In order to secure the primary insulating block to the secondary corner structure, the positions of the different primary insulating blocks are first determined and marked on the secondary corner structure. The primary insulating block is then glued and added separately to the secondary corner structure. Then, after checking and possibly setting the position of the primary insulating block according to the markings on the secondary corner structure, pressure is applied to the primary insulating block for fixing by gluing it to the secondary corner structure.

However, the application of pressure on the primary insulating block causes a displacement of said primary insulating block with respect to the position provided by the mark. Therefore, this method is not entirely satisfactory, and requires perfect control of the pressure application step. In fact, the fixing of the primary insulating block to the secondary corner structure in the wrong position cannot be corrected without degrading the corner structure, resulting in a loss of the entire corner structure.

Disclosure of Invention

One idea on which the present invention is based is to facilitate the production of a sealed and thermally insulated tank structure comprising a secondary insulating structure to which a plurality of primary thermal insulation blocks are fixed. One idea on which the invention is based is to allow the primary insulating block to be fixed to the secondary insulating structure in a controlled positioning manner. In particular, one idea on which the invention is based is to ensure the relative positioning of different primary insulating blocks on the secondary insulating structure. The invention is therefore based on the idea of fixing the primary insulating blocks to the secondary insulating structure while maintaining a predetermined spacing between the primary insulating blocks.

According to one embodiment, the present invention provides a method for manufacturing a tank structural element, the method comprising the steps of:

-providing a secondary insulation structure comprising a support surface,

-providing a plurality of primary insulating blocks,

-positioning a spacer in an insertion position in which the spacer is inserted between a first primary insulating block of the plurality of primary insulating blocks and a second primary insulating block of the plurality of primary insulating blocks, such that the spacer keeps a spacing between the first primary insulating block and the second primary insulating block within a tolerance range,

-fixing a primary insulating block onto a supporting surface of a secondary insulating structure, maintaining a spacer in an interposed position, so that the spacing between the first and second primary insulating blocks is maintained within a tolerance range when the first and second primary insulating blocks are fixed.

By virtue of these features, it is possible to simply and quickly position the primary insulating block on the secondary insulating structure. In fact, in order to position the primary insulating blocks, it is sufficient to have the spacer enter between two primary insulating blocks without any marking on the secondary insulating structure. Furthermore, since the spacers are kept interposed between the primary insulating blocks when positioning the primary insulating blocks on the secondary insulating structure, the method can ensure a controlled spacing between the primary insulating blocks. In addition, the spacing is also controlled when pressure is applied to secure the primary insulating block to the secondary insulating structure, the spacer remaining engaged with the primary insulating block when the pressure is applied. This tolerance separating two adjacent primary insulating blocks makes it possible to overcome the manufacturing tolerances of the primary insulating blocks while ensuring that the spacing between these blocks is within a controlled interval.

According to embodiments, such a manufacturing method may include one or more of the following features.

According to one embodiment, after fixing the primary insulating block to the supporting surface, the spacer is removed from the insertion position.

According to one embodiment, a secondary insulation structure includes a secondary insulation panel and a secondary sealing film adhered to the insulation panel.

According to one embodiment, the secondary insulation panel comprises an insulation lining and an inner rigid plate. According to one embodiment, the secondary insulating plate further comprises an outer rigid plate, the insulating lining being interposed between the inner rigid plate and the outer rigid plate. According to one embodiment, the insulating lining is bonded to the inner rigid plate and/or the outer rigid plate. According to one embodiment, the inner rigid plate and/or the outer rigid plate is made of wood, plywood or a composite material.

According to one embodiment, the secondary sealing film comprises a laminated composite comprising a metal layer, for example an aluminium layer, interposed between two fibrous layers, for example a glass fibre layer and a resin layer.

According to one embodiment, the secondary insulation structure has a parallelepiped form, for example a cuboid form.

According to one embodiment, the insulation lining is an insulation foam, preferably a fibre-reinforced insulation foam, such as a glass fibre-reinforced polyurethane foam.

According to one embodiment, the method further comprises:

-applying an adhesive to the support surface and to the face of the primary insulating block intended to rest on the support surface, before fixing the block to the support surface, and

the step of securing the primary insulating block to the support surface of the secondary insulating structure comprises:

-applying a pressure on one of the primary insulating block and the secondary insulating structure towards the other of the primary insulating block and the secondary insulating structure, so as to fix said primary insulating block to the secondary insulating structure, while keeping the spacer interposed between the first primary insulating block and the second primary insulating block.

The pressure force capable of fixing the primary insulating block to the secondary insulating structure, and more particularly to the supporting surface of the secondary insulating structure, can be generated in various ways. Thus, according to one embodiment, the method comprises the step of pressing the primary insulating block against the supporting surface of the secondary insulating structure. According to one embodiment, the supporting surface of the secondary insulating structure is pressed against the primary insulating block.

According to one embodiment, the primary insulating block is fixed to the secondary insulating structure by gluing. According to one embodiment, this gluing is performed by means of a polymer glue, preferably a polyurethane glue.

According to one embodiment, the method further comprises the steps of:

-providing a positioning device comprising a frame having a bearing surface and a spacer protruding from the bearing surface of the frame such that the bearing surface has a first bearing part and a second bearing part on either side of the spacer,

-arranging the positioning means on the primary insulating block so that the first bearing portion rests on the first primary insulating block and the second bearing portion rests on the second primary insulating block, the step of exerting pressure on said first and second primary insulating blocks comprising pressing the first bearing portion on the first primary insulating block and the second bearing portion on the second primary insulating block.

By virtue of these features, a frame can be used to apply pressure to the primary insulating block in order to secure the primary insulating block to the secondary insulating structure. Thus, the primary insulating block can be simply and quickly positioned and then fixed to the secondary insulating structure, the positioning means making it possible both to position the primary insulating block and to apply pressure to fix the primary insulating block to the secondary insulating structure.

According to one embodiment, the primary insulation block comprises an insulation element and a metal plate, the length of the metal plate being greater than the length of the insulation element, the metal plate covering the insulation element in such a way that two opposite edges of the metal plate extend longitudinally beyond respective end faces of the insulation element. In other words, the primary insulating block has projecting portions formed by opposite edges of the metal plate, which extend beyond opposite surfaces of the insulating element.

The insulating element of the primary insulating block may be made of a variety of materials. For example, the insulating element may be made of wood, such as plywood, insulating foam, such as polyurethane foam, for example fibre-reinforced high-density polyurethane foam, or even of a combination of materials, such as insulating foam sandwiched between two plywood panels, or even insulating foam layers associated with plywood panels. Also, the metal plate may be made of various materials such as steel, invar, and the like.

According to one embodiment, the primary insulating block has a primary insulating plate and a metal plate having an edge protruding beyond the primary insulating plate, the method further comprising the steps of:

-providing a positioning device comprising a frame and a spacer comprising two fixing means,

and wherein the step of positioning the spacer in the insertion position comprises fixing the projecting edges of the first and second primary insulating blocks to the spacer by respective fixing means of the spacer.

The securing means may take a variety of forms. According to one embodiment, these fixing means comprise a clamp and the projecting edge of the primary insulating block is fixed by being clamped in said clamp. According to one embodiment, the spacer comprises two rails comprising grooves, said rails protruding from the frame in opposite directions, the fixing of the protruding edges of the primary insulating blocks being performed by inserting said protruding edges into the grooves of the respective rails. In other words, according to this embodiment, the fixing means are rails comprising grooves into which the projecting edges of the respective primary insulating blocks are inserted to fix said primary insulating blocks to the spacer.

Inserting the protruding edge of the metal plate into the groove allows a good fit between the spacer and the primary insulating block. In particular, such an interposition makes it possible to block the displacement of the primary insulating blocks towards each other, and also to keep the primary insulating blocks immobile in the height direction of the primary insulating blocks.

In general, in the case of a positioning device comprising a plurality of adjacent spacers formed by rails, the cooperation of the metal plate of the primary insulating block with two adjacent spacers makes it possible to lock the primary insulating block in position at the positioning device. In particular, this cooperation makes it possible to simultaneously displace a group of primary insulating blocks, each cooperating with two adjacent spacers.

According to one embodiment, the spacer comprises a support and a pair of clamps arranged on the support at a predetermined pitch, said clamps comprising two movable lugs and a setting device capable of displacing both lugs simultaneously and by the same distance in opposite directions to define the pitch of said lugs, the method further comprising the steps of:

-entering a first primary insulation block into one of the clamps, and then setting the position of the protrusion of said clamp such that said first primary insulation block is fixed in said clamp, and

-entering a second primary insulation block into another one of the clamps, and then setting the position of the protrusion of the clamp such that the second primary insulation block is fixed in the clamp and such that the mid-plane of the first primary insulation block is spaced apart from the mid-plane of the second primary insulation block by a distance within an allowable range.

Such spacers and the positioning of the projections allow manufacturing tolerances of the primary insulating blocks to be overcome while maintaining a controlled spacing between the primary insulating blocks. Thus, the male portion of the clamp may be displaced to accommodate different primary insulating blocks while positioning the primary insulating blocks centered at predetermined positions spaced apart to ensure a predetermined spacing from the primary insulating blocks.

According to one embodiment, the step of fixing the primary insulating block to the supporting surface of the secondary insulating structure comprises the step of positioning the spacer with respect to the end of the secondary insulating structure.

Such positioning means may take a variety of forms. According to one embodiment, such a positioning device comprises a locking bar extending from an end of the frame at right angles to the longitudinal direction of the frame, said locking bar forming a first abutment surface for cooperating with a second abutment surface carried by the secondary insulating structure to lock the positioning device in position relative to the secondary insulating structure. Thus, according to one embodiment, the method further comprises the step of abutting a first abutment surface fixed together with the spacer in the displaced condition against a second abutment surface carried by the secondary insulating structure to prevent displacement of the spacer relative to the secondary insulating structure, the first abutment surface being spaced from the spacer by a predetermined distance. According to one embodiment, the second abutment surface carried by the secondary insulating structure is a lateral end face of the secondary insulating structure.

According to one embodiment, the positioning device comprises a first marker for cooperating with a second marker carried by the secondary insulating structure, the matching of said markers making it possible to determine the arrangement of the positioning device with respect to the secondary insulating structure. Thus, according to one embodiment, the method further comprises the steps of: the indicia carried by the spacer and the indicia carried by the secondary insulating structure are matched to position the spacer in a predetermined position relative to the secondary insulating structure.

According to one embodiment, the method further comprises the steps of:

-providing a plurality of spacers, the spacers,

positioning each spacer in an insertion position in which each spacer is interposed between two adjacent primary insulating blocks of the plurality of primary insulating blocks such that the spacer maintains a pitch between adjacent primary insulating blocks within a tolerance range, the spacer being interposed between adjacent primary insulating blocks,

-fixing primary insulating blocks on a supporting surface of a secondary insulating structure, the spacers being held between adjacent primary insulating blocks so as to maintain a spacing between the adjacent primary insulating blocks within a tolerance range when fixing the adjacent primary insulating blocks.

According to one embodiment, the method further comprises the step of providing a positioning device comprising a frame and a plurality of spacers, the spacers of the plurality of spacers being arranged at regular intervals on the frame.

According to one embodiment, the supporting surface has a first supporting surface portion and a second supporting surface portion forming corner portions, a first spacer of the plurality of spacers is interposed between adjacent two primary insulating blocks on the first supporting surface portion, and a second spacer of the plurality of spacers is interposed between adjacent two primary insulating blocks on the second supporting surface portion, the method further comprising the step of fixing the first spacer and the second spacer together with displacement.

This method makes it possible to correctly position a set of primary insulating blocks on the corner portion secondary insulating structure. Thus, the method allows for a simple, fast and reliable production of sealed and thermally insulating tank corner structures by ensuring separation and positioning of the primary insulation blocks simultaneously on both supporting surface parts of the corner secondary insulation structures.

According to one embodiment, the positioning device further has a clamping device. Such a clamping device is particularly useful in the case of corner structures associated with spacers that block displacement of the primary insulation blocks relative to the positioning device, such as for example the rails as described above, since it is made possible to displace the corner structures as a single piece using the clamping device of the positioning device.

According to one embodiment, the method further comprises securing the one or more spacers and the primary insulating block together such that the primary insulating block and the one or more spacers form a group that is secured together with displacement.

The insulating block and the one or more spacers may be secured together in a variety of ways.

According to one embodiment, the primary insulating block comprises a stud protruding from an inner surface of the metal plate, said inner surface being opposite the insulating element. Such studs are for example studs allowing to fix clamps subsequently used in the production of cans. For example, such a clamp may absorb the load of fixing the corrugated corner portions by welding to ensure continuity of the sealing film between the two metal plates of the adjacent two primary insulating blocks, or may even fix the pressure rod to apply a fixing pressure to the intermediate primary insulating block interposed between the primary insulating blocks of the adjacent two corner structures in the can. The spacer may then be secured with the primary insulating block by mating with the stud of the primary insulating block. For example, in the case of the positioning device described above, the positioning device may include one or more through holes, and the step of inserting the spacer between the first primary insulating block and the second primary insulating block includes inserting one or more studs of the first primary insulating block and/or the second primary insulating block into the through holes, and fixing the positioning device to the one or more studs by fixing means, such as nuts or the like, provided on the studs, thereby allowing the positioning device and the studs to be fixed together.

According to one embodiment, such a through hole may be oval in shape in order to be able to adapt the position of said stud on the positioning device.

Also, these studs may be used in conjunction with a moving device, such as a hoist crane, winch, or the like, to displace the assembly formed by the spacer and the primary insulating block.

The step of fixing the spacer and the primary insulating block together is preferably performed before the step of applying the adhesive. Thus, the primary insulating blocks can be safely handled and displaced, and the application of adhesive can be performed on the individual primary insulating blocks of the assembly during the same step of applying adhesive for the set of said primary insulating blocks.

According to one embodiment, the invention also provides a device for positioning a primary insulating block of a sealed and thermally insulating tank structural element, the structural element comprising a secondary insulating block having a supporting surface and a primary insulating block intended to rest on the supporting surface, and a plurality of primary insulating blocks, the positioning device comprising a frame and a plurality of spacers arranged on the frame in the longitudinal direction of the frame, the plurality of spacers projecting from the frame in a parallel manner in a direction at right angles to the longitudinal direction of the frame, the spacers defining a predetermined spacing in the predetermined longitudinal direction of the frame and being intended to be interposed between two adjacent primary insulating blocks of the plurality of insulating blocks so as to maintain the predetermined spacing in the longitudinal direction of the frame between the two adjacent primary insulating blocks of the plurality of primary insulating blocks.

Such a positioning device enables a reliable and simple positioning of the primary insulation block on the secondary insulation structure. In particular, such positioning means make it possible to maintain a controlled spacing between the primary insulating blocks when they are positioned and fixed to the secondary insulating structure.

According to embodiments, such a positioning device may comprise one or more of the following features.

According to one embodiment, the spacers are arranged at regular intervals along the frame.

According to one embodiment, the frame has a cross section in the form of a flat, and the spacers protrude from the flat faces of the frame.

According to one embodiment, the primary insulating block has a primary insulating plate and a metal plate having an edge protruding beyond the primary insulating plate.

According to one embodiment, the spacer comprises fixing means able to fix the protruding edge of the primary insulating block to the spacer.

According to one embodiment, the primary insulating blocks have primary insulating plates and a metal plate having an edge projecting beyond the primary insulating plates, and the spacer comprises two rails comprising grooves projecting in opposite orientations from the frame, so that each of these grooves can receive the projecting edge of a respective primary insulating block.

According to one embodiment, the device further comprises means for positioning the frame on the secondary insulation structure so as to arrange the spacer at a predetermined position with respect to the secondary insulation structure.

According to one embodiment, the spacer of the plurality of spacers comprises a pair of clamps arranged on the support with a predetermined spacing between them, the support of the plurality of spacers forming a frame, said clamps comprising two movable lugs and setting means capable of shifting the two lugs simultaneously and by the same distance in opposite directions to define the spacing of said lugs.

According to one embodiment, the spacer and advantageously the plurality of spacers are made of a material selected from wood and polymeric materials, such as high density polyethylene, polytetrafluoroethylene.

According to one embodiment, the spacer is displaced in a plane defined by a gap between two primary insulating blocks, in which the spacer is interposed, in order to remove the spacer in a direction orthogonal or parallel to the supporting surface, for example, or in an oblique direction, that is to say by one component orthogonal to the supporting surface and one component parallel to the supporting surface.

Drawings

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

Fig. 1 is a schematic perspective view of a corner structure of a sealed and thermally insulated can;

fig. 2 is a schematic cross-sectional view of a positioning device according to a first embodiment cooperating with a plurality of primary insulation blocks as shown in fig. 1;

fig. 3 is a schematic perspective view of the positioning device of fig. 2 in cooperation with a plurality of primary insulating blocks;

FIG. 4 is a top view of a modified embodiment of the positioning device of FIG. 2;

FIG. 5 is a schematic perspective view of a positioning assembly including two positioning devices and cooperating with the corner structure shown in FIG. 1, according to a second embodiment;

fig. 6 is a schematic cross-sectional view of a positioning device according to a second embodiment in cooperation with a plurality of primary insulating blocks;

fig. 7 is a schematic view of a positioning device according to a third embodiment in cooperation with a plurality of primary insulating blocks.

Detailed Description

By convention, "upper" or "above" will denote a position closer to the interior of the tank to be produced, while "lower" or "below" will denote a position closer to the load-bearing structure of the tank to be produced, regardless of the orientation of the tank walls with respect to the earth's gravitational field. Likewise, "top" or "inner" will be used to define elements closer to the interior of the tank to be produced, while "bottom" or "outer" will be used to define elements closer to the load-bearing structure of the tank to be produced.

The sealed and thermally insulated tank comprises a plurality of walls, each wall being formed by at least one thermal insulation barrier and at least one sealing film. In an embodiment to be described, the tank wall includes a secondary thermal insulation barrier, a secondary sealing film supported by the secondary thermal insulation barrier, a primary thermal insulation barrier secured to the secondary sealing film, and a primary sealing film supported by the primary thermal insulation barrier.

At the corner portions of the sealed and thermally insulating tank, corner structures 1 are placed at the joints between the two walls. The corner structure 1 can ensure the continuity of different thermal insulation barriers and sealing films at the joint between a first tank wall and a second tank wall, which are inclined with respect to each other by a determined angle, for example an angle of 90 ° or an angle of 135 °.

As shown in fig. 1, such a corner structure 1 comprises a secondary corner structure 2, on which secondary corner structure 2 a plurality of primary insulation blocks 3 rest.

The secondary corner structure 2 comprises a secondary thermal insulation barrier portion to which a secondary sealing film portion is glued. More specifically, the secondary corner structure 2 includes a first secondary insulating plate 4 and a second secondary insulating plate 5. These secondary insulating

plates

4, 5 each comprise: a rigid outer panel 6, for example made of plywood; an insulating lining 7, for example made of fibre-reinforced polyurethane foam; and a rigid inner panel 8, for example made of plywood or composite material. In these secondary insulating

plates

4, 5, the inner plate 8 is parallel to the bottom plate 6.

The two secondary insulating

plates

4, 5 have a bevel 9 and are arranged edge to edge at said bevel 9 such that the first secondary insulating plate 4 extends in the plane of the first tank wall and such that the second secondary insulating plate 5 extends in the plane of the second tank wall, the first and second tank walls forming corner portions of the tank.

The secondary sealing membrane portion comprises a layer of rigid impermeable composite membrane 10 glued to the rigid inner plate 8 of each of the secondary insulating

plates

4, 5. These impermeable composite films 10 are produced, for example, in the form of a laminated composite comprising an aluminium layer interposed between a glass fibre layer and a resin layer. These impermeable composite membranes 10 are tightly joined, for example, by a flexible impermeable composite membrane 11. Such a flexible impermeable composite film 11 is for example made of a laminated composite material comprising an aluminium layer interposed between two layers of glass fibres.

The first secondary insulating plate 4 and the secondary sealing membrane portion carried by said first secondary insulating plate 4 form a first supporting surface of the secondary corner structure 2. Likewise, the second secondary insulating plate 5 and the secondary sealing membrane portion carried by said second secondary insulating plate 4 form a second supporting surface of the secondary corner structure 2. These support surfaces make it possible to fix the primary insulating block 3 to the secondary corner structure 2.

As shown in fig. 1, 3 or 6, the primary insulating block 3 comprises a metallic angle iron 14, a first primary block 12 in the form of a parallelepiped and a second primary block 13 in the form of a parallelepiped. A first wing 15 of the metal angle 14 is fixed to the first primary block 12 and a second wing 16 of the metal angle 14 is fixed to the second primary block 13. The first wing 15 and the second wing 16 extend in respective planes according to an angle corresponding to a corner of the tank. For example, metal angle bars 14 may securely fix the primary sealing membrane to the primary insulating block 3. Furthermore, the metal angle 14 can firmly fix the corrugated corner portions (not shown), thereby ensuring impermeability of the primary sealing membrane between two adjacent metal angles 14.

The first elementary block 12 and the second elementary block have the same size. Furthermore, the metal angle-bars 14 have a length dimension taken in the direction of the edge formed by said metal angle-bars 14, this length dimension of the metal angle-bars 14 being greater than the dimension of the

primary blocks

12 and 13 in said direction. The angle iron 14 is fixed to the primary blocks 12 and 13 in such a way that each

wing

15 and 16 of said angle iron 14 has two opposite projecting edges 17 extending beyond the corresponding edges of the

primary blocks

12 and 13. In other words, the projecting edges 17 of the

wings

15 and 16 extend beyond the two opposite edges of the

primary blocks

12 and 13.

Furthermore, as shown in fig. 1 and 3, each

wing

15, 16 of the metal angle 14 has an inwardly projecting stud 26 on the inner surface of the wing, i.e. on the face opposite the primary blocks 12 and 13. These studs 26 allow fixing of clamps that are subsequently used in the production of sealed and thermally insulating tanks.

As shown in fig. 1, a plurality of primary insulating blocks 3 are secured to the secondary corner structure 2 along an edge 18 formed between the secondary insulating

plates

4 and 5. Each primary insulating block 3 is fixed to the secondary corner structure 2 in such a way that the first primary block 12 is fixed on a first supporting surface of the secondary corner structure 2 and the second primary block 13 is fixed on a second supporting surface of the secondary corner structure 2.

The primary blocks 12 and 13 are secured to the support surface of the secondary corner structure 2 by adhesive. Such adhesives are, for example, polymer glues, such as polyurethane glues. In fig. 1,

primary blocks

12 and 13 are fixed on a flexible composite film portion 11, and the flexible composite film portion 11 is fixed on secondary insulating

plates

4 and 5.

In fixing the primary insulation blocks 3 to the secondary corner structure 2 it is important to control the spacing between the metal angle irons 14 of two adjacent primary insulation blocks 3. Furthermore, it is also important to control the distance between the end primary insulating blocks and the edges of the respective secondary corner structures.

For this purpose, a positioning device 19 is used. Fig. 2 to 7 show different embodiments of such positioning means 19 and the use of such positioning means 19 for satisfactorily fixing the primary insulation block 3 to the secondary corner structure 2.

Fig. 2 and 3 show a positioning device 19 according to a first embodiment. In this first embodiment, the positioning means comprise a frame 20 and a plurality of spacers 21.

The frame 20 has the form of a parallelepiped, generally in the form of a bar or plate of rectangular section. The frame 20 includes a flat exterior face 22. The spacers 21 protrude from said flat outer face 22 of the frame 20. More specifically, the spacer 21 has a rectangular-shaped cross section and extends at right angles to the outside face 22. Each spacer 21 thus has a first face 23 at right angles to the longitudinal direction of the frame 20 and a second face 24 opposite the first face 23 and also extending at right angles to the longitudinal direction of the frame 20. The first face 23 and the second face 24 of the spacer 21 are parallel and separated by a predetermined spacing 25. This spacing 25 corresponds to the minimum spacing that is desired to be maintained between two primary insulating blocks 3 when positioning and securing said primary insulating blocks 3 to the secondary corner structure 2.

In addition, the frame 20 has a plurality of through holes 27 to allow the studs 26 to pass through the frame 20.

As indicated by the arrow 28 in fig. 3, the positioning means 19 according to this first embodiment are arranged on a plurality of adjacent primary insulation blocks 3. For this purpose, the outer face 22 of the frame 20 rests against the inner face 29 of the first wing 15 of the metal angle 14 of the primary insulating block 3. Furthermore, the studs 26 of the primary insulating block 3 are received in the apertures 27 of the frame. Furthermore, the spacer 21 of the positioning device 19 is placed between the adjacent primary insulating blocks 3.

Therefore, as shown in fig. 2, when the positioning device 19 is arranged on the primary insulating blocks 3, each spacer 21 is interposed between adjacent two primary insulating blocks 3. In addition, the stud 26 passes through the through hole 27 of the frame 20. Finally, the outer surface 22 of the frame has a plurality of bearing portions 30, the bearing portions 30 bearing on the inner face 29 of the first wing 15 of the metal angle 14.

The spacers 21 can ensure a defined and fixed distance between two adjacent primary insulating blocks 3. In fact, as the spacer 21 is interposed between two adjacent primary insulating blocks 3, the opposite faces 23 and 24 of said spacer 21 form abutment surfaces, preventing said adjacent primary insulating blocks 3 from coming together. Therefore, when the positioning device is disposed on the primary insulating blocks, the minimum interval separates adjacent two primary insulating blocks 3, in which the positioning device is disposed, of the plurality of primary insulating blocks 3. A number of arrangements are possible to secure the primary insulating block 3 and the positioning means 19 together. In the embodiment shown, the positioning means 19 are fixed to all the primary insulating blocks 3 for being fixed to the two secondary insulating

plates

4, 5. However, according to other embodiments, the positioning means may be fixed only to a portion of the primary insulating blocks 3 for fixing to the two secondary insulating

plates

4, 5, i.e. the positioning means may be fixed only to at least two sets of two primary insulating blocks 3. For example, a nut (not shown) may be screwed onto the stud 26 so as to sandwich the frame 20 between the nut and the inner face 29 of the first wing 15 of the metal angle 14. After the primary insulating block 3 is fixed to the secondary corner structure 2 by gluing, these nuts are removed before the positioning means are removed.

When the positioning device 19 is arranged on the primary insulation block 3, the primary insulation block 3 can be handled as a single piece using a mobile bridge crane, a boom or any other hoisting device.

This joint displacement of the primary insulating blocks 3 makes it possible to fix the primary insulating blocks 3 to the secondary corner structures 2 in a grouped manner. Thus, the primary insulating blocks 3 fixed to the positioning means 19 are all glued together in the same gluing step. Typically, the assembly formed by the primary insulating block 3 and the positioning means 19 is moved by means of a winch, crane or any other device suitable for making all the external faces of the primary insulating block 3 accessible. For example, the primary insulating block is raised to a sufficient height to allow access to the exterior face of the primary insulating block 3, or the assembly is turned over to allow access to the exterior face. The primary insulating blocks 3 are then positioned together on the secondary corner structure 2 when the primary insulating blocks 3 are glued. When the primary insulating blocks 3 are positioned on the secondary corner structures 2, the positioning means 19 remain engaged with the primary insulating blocks 3 to maintain control of the spacing between adjacent primary insulating blocks 3.

According to a first variant, the markings are made on the secondary corner structure 2 before the primary insulating block 3 is fixed to the secondary corner structure 2. The marking may be made in a number of ways, for example by a pencil stroke, a piece of adhesive or the like. The mark indicates a desired position of the end primary insulating block 3 among the plurality of primary insulating blocks 3. The marking allows for controlling the positioning of the end primary insulating block 3 relative to the edge of the secondary corner structure 2. Furthermore, this marking also allows the positioning of the primary insulating block 3 with respect to the edge of the secondary corner structure 2, due to the cooperation of the primary insulating block 3 with the positioning means 19.

According to a second variant, the frame 20 has a projection (not shown) projecting parallel to the spacer. The protrusion allows the frame 20 to be positioned relative to a side surface of the secondary corner structure 2, such as the side surface shown with reference numeral 52 in fig. 1. Typically, the protrusion forms a first abutment surface and the side surface 52 forms a second abutment surface which cooperates with the first abutment surface to locate the protrusion, and thus the plurality of primary insulating blocks 3, relative to the secondary corner structure 2.

When positioning the primary insulating block 3 on the secondary corner structure 2, the primary insulating block is arranged on top of the supporting surface of the secondary corner structure 2 and the assembly formed by the primary insulating block 3 and the positioning means 19 is translated until the protrusions of the frame 20 come into contact with the side surface 52 of the secondary corner structure 2. A single vertical translation then makes it possible to apply the primary insulating block 3 to the secondary corner structure 2. This variant provides the advantage of avoiding contact between the primary insulating block 3 and the secondary corner structure 2 before the position of the primary insulating block 3 relative to the secondary corner structure 2 is properly determined. Furthermore, this variant can omit the step of marking the position of the end primary insulating block 3 on the secondary corner structure 2 with a marker.

In order to avoid degradation of the secondary sealing membrane, an indentation can be made on the reference joining region forming the abutment surface carried by the secondary corner structure 2.

Furthermore, it is also possible to provide second protrusions on the opposite end of the frame to wedge the frame 20 and thus all the primary insulating blocks 3 cooperating with the positioning means 19 to the opposite sides of the secondary corner structure 2. The male part is fixedly mounted on the frame 20 or adjustably mounted on the frame 20, for example by sliding. The wedging of the two opposite sides of the secondary corner structure 2 ensures that the set of primary insulating blocks 3 does not translate when positioning said primary insulating blocks 3 on the secondary corner structure 2 and that a good management of the separation between the end primary insulating blocks 3 and the edges of the secondary corner structure 2 is ensured.

When the primary insulating block 3 is positioned according to the desired arrangement on the secondary corner structure 2, a pressure is exerted on the primary insulating block 3 to ensure that the primary insulating block 3 is fixed to the secondary corner structure 2 by gluing. When this pressure is applied to the primary insulating blocks 3, the positioning means 19 remain engaged with said blocks 3 to keep the spacers 21 interposed between two adjacent blocks 3, thus ensuring that the blocks 3 are kept apart by a controlled spacing even when this pressure is applied.

This pressure is advantageously applied by the positioning means 19, the bearing portion 30 of the outer face 22 of the frame 20 being pressed against the inner surface 29 of the primary insulating block 3. Furthermore, the application of this pressure by means of the positioning means 19 allows the spacers 21 to be simply held between adjacent primary insulating blocks 3.

According to an embodiment not shown, the frame 20 is mounted, for example, so as to be movable on a support. Such a support has a load absorbing member, such as a plate, a tubular structure or any other means allowing good load absorption. The secondary corner structure 2 is arranged on and/or against the load-absorbing member. The primary insulating block 3 is arranged on the frame 20, for example in the frame portion of the frame 20, as shown in fig. 2 and 4, by screwing a nut (not shown) onto the stud 26 so as to clamp the frame 20 between said nut and the inner face 29 of the first wing 15 of the metal angle 14. The frame 20 with the primary insulating block 3 mounted thereon is then moved towards the load absorbing member to compress the primary insulating block 3 and the secondary corner structure 2 and secure the primary insulating block 3 to the secondary corner structure 2.

When the primary insulation block 3 is fixed on the secondary corner structure 2, the positioning means 19 are removed and the construction of the sealed and thermally insulated tank can be continued.

In the embodiment shown in fig. 3, to remove the positioning means, the frame 20 and the spacers 21 are displaced in such a way that the spacers 21 are each displaced in the plane of the gap between the two primary insulating blocks 3 in which said spacers 21 are interposed. This displacement may correspond in particular to a vertical translation orthogonal to the support surface and in the opposite direction to the primary insulating block 3, and to a horizontal translation or tilting translation parallel to the support surface and in the opposite direction to the primary insulating block 3, i.e. the displacement has a component orthogonal to the support surface and has a component parallel to the support surface.

In order to limit the friction between the spacer 21 and the primary insulating block 3, during this removal step, the spacer 21 is advantageously made of a material having a low friction coefficient with the contact surface of the primary element 3. Furthermore, the spacer 21 is advantageously made of a material chosen from polymeric materials such as high-density polyethylene, polytetrafluoroethylene and wood.

Fig. 4 shows a variant embodiment of the positioning device 19 shown in fig. 3. In this modification, the through-hole 27 has an oval form to allow the primary insulating block 3 to be displaced between the adjacent two spacers 21 in the longitudinal direction of the frame 20. Such through holes 27 allow better management of the tolerances in positioning the studs 26 on the metal angle 14.

Fig. 5 and 6 show a second embodiment of the positioning device 19.

According to this second embodiment, the frame 20 is a simple rod. Furthermore, each spacer 21 comprises two rails 31. These rails 31 have a "U" shaped profile to form a groove 32. The rail 31 protrudes from the frame 20 at right angles to the longitudinal direction of the frame 20. Furthermore, the two rails 31 of the spacer 21 have opposite orientations. In other words, the first groove 32 of the spacer 21 is directed towards a first end of the frame 20 and the second groove 32 of said spacer 21 is directed towards a second end of the frame 20, said second end of the frame 20 being opposite to the first end of the frame 20.

The two rails are arranged on the frame 20 such that the bottoms of the grooves 32 are separated by a desired predetermined distance to separate adjacent two primary insulating blocks 3.

In contrast to the positioning device 19 according to the first embodiment shown in fig. 2 to 4, the spacer 21 of the positioning device 19 according to this second embodiment is inserted between the metal angle pieces 14 of two adjacent primary insulation blocks 3 from one side of said primary insulation blocks 3. More specifically, the positioning means 19 are arranged on the primary insulating block 3 by embedding the projecting edge 17 of the

wing

15 or 16 of the metal angle 14 of the primary insulating block 3 in the groove 32. Thus, the grooves 32 of the two tracks 31 of the same spacer 21 each cooperate with the projecting edge of a respective primary insulating block 3, said blocks 3 being adjacent and maintained spaced apart by a predetermined distance defined by the spacing between the two tracks 31.

Inserting the protruding edges 17 of the primary insulating block 3 into the opposing grooves 32 of two adjacent spacers also makes it possible to lock the primary insulating block 3 in displacement in a direction other than the sliding direction.

Furthermore, to ensure such locking in position of the end primary insulating blocks 3, the positioning device also comprises an end rail 33 arranged at each end of the frame 20. These end rails 33 are similar to the rails 31 of the spacer 21 and project from the frame 20 in an orientation opposite to the adjacent rails 31. In other words, the groove of the end rail 33 faces and faces the groove 32 of the rail 31 of the spacer 21 adjacent to the end rail 33.

When the positioning means are arranged on the set of primary insulating blocks 3, the projecting edges 17 of said primary insulating blocks 3 all enter into the groove of the

corresponding track

31 or 33. Thus, the set of primary insulating blocks 3 can be displaced as a single piece.

To remove such positioning means, the positioning means are displaced by horizontal translation by sliding the grooves of the

tracks

31, 33 relative to the protruding edges 17 of the adjacent primary insulation blocks when the primary insulation blocks 7 have been fixed.

Fig. 6 shows an assembly which makes it possible to displace the set of primary insulating blocks 3 for mounting as a single piece on the secondary corner structure 2. In the present embodiment, the positioning means comprise a threaded rod 34 at each of the ends of the frame 20. The first positioning means 35 are arranged on the primary insulating block 3, as indicated by the arrow 36, by inserting the projecting edge 17 of the first wing 15 of the metal angle 14 of the primary insulating block 3 into the grooves of the

rails

31 and 33 of said first positioning means 35. Likewise, the second positioning means 37 are arranged on the primary insulation block 3, as indicated by the arrow 38, by inserting the projecting edge 17 of the second wing 16 of the metal angle 14 of the primary insulation block 3 into the grooves of the

rails

31 and 33 of said second positioning means 37.

The first positioning means 35 and the second positioning means 37 are fixed together by means of spacers 39. Each spacer 39 comprises a rod having a through hole 40 at its end. Spacers 39 are fixed to each end of the positioning means 35 and 37, the threaded rods 34 of the two positioning means 35 and 37 entering the through holes 40. Nuts (not shown) threaded onto the protruding portions of the threaded rods 34 allow the spacers 39 to be secured with the

positioning devices

35 and 37.

When the first and second positioning means 35, 27 are arranged on the primary insulating block 3 and fixed together by the spacer 39, the first and second positioning means 35, 27 cannot be removed from the primary insulating block 3. In fact, on the one hand, the cooperation between the

rails

31 and 33 and the projecting edge 17 makes the positioning means 35 and 37 immovable in directions other than the direction in which the projecting edge 17 is inserted into the

rails

31 and 33, and on the other hand, the spacer 39 prevents relative displacements between said positioning means 35 and 37.

Thus, the first and second positioning means 35, 37 form, with the spacer 39 and the primary insulating block 3, an assembly that can be displaced as a single piece. For this purpose, a clamping device 41 with a "U" shaped profile can be used, as shown in fig. 6. The clamping device 41 comprises a rod 42, at the centre of which rod 42 a lifting ring 43 is arranged. The clamping device 41 further comprises two protrusions 44, each protrusion 44 protruding from a respective end of the rod 42. The end of the boss 44 opposite the rod 42 has a through hole 45, the through hole 45 being able to cooperate with the threaded rod 34 of one of the positioning means 35 or 37, as exemplified by the second positioning means 37 in fig. 6, so that the clamping means is fixed to the assembly formed by the positioning means 35 and 37, the spacer 39 and the primary insulating block 3. Thus, the assembly can be displaced as a single piece to maintain the required spacing between the primary insulation blocks 3, for example by a crane attached to the lifting ring 43. In order to ensure the removal of the positioning means 35, 37, the spacer 39 is disconnected beforehand from the positioning means, and then each of the positioning means 37, 39 is displaced in translation in a direction parallel to the support surface and opposite to the primary insulating block 3, so as to slide the groove of the

track

31, 33 with respect to the projecting edge 17 of the adjacent primary insulating block 3.

Fig. 7 schematically shows a third embodiment of the positioning device 19. In this third embodiment, the positioning device 19 comprises a support 46, on which support 46 a plurality of clamps 47 are arranged.

Each clamp 47 comprises a setting device 48 and two protrusions 49. The setting device 48 allows the projection 49 to move symmetrically with respect to the centre 50 of the clamp 47. Such self-centering is produced, for example, by a self-centering mechanism of the bevel gage type. The clamping elements 47 are arranged on the support element 46 according to a determined spacing 51 of the centers 50.

Each clamp 47 is arranged such that the projection 49 sandwiches the primary insulating block 3, for example at the projecting edge 17, when the positioning means 19 is arranged on the primary insulating block 3. This sandwiching of the primary insulation block 3 is such that the center of said primary insulation block 3, for example at the stud 26, is arranged at the center 50 of the clamp 47, since the setting means 48 allows the boss 49 to self-center when setting the boss 49 in place. Therefore, the centers of the adjacent primary insulation blocks 3 are spaced by a distance 51 so that the adjacent two primary insulation blocks 3 are separated by a controlled distance.

To ensure removal of such positioning means 19, setting means acting on each clamp 47 can be foreseen.

Although the invention has been described with respect to several particular embodiments, it is clear that the invention is in no way limited thereto and that the invention comprises all technical equivalents of the means described and combinations thereof if they fall within the scope of the invention as defined in the claims.

For example, fig. 1 shows a tank corner structure for a 90 ° corner, but the invention is similarly applicable to a different tank corner, say for example a 135 ° tank corner.

Furthermore, such a method or device can also be used to ensure the positioning and fixing of one or more primary insulating blocks 3, as described above, the primary insulating block 3 straddling between two secondary insulating

plates

4, 5, one primary insulating block 3 being placed alongside the other along a corner of the tank.

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

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

Claims

1. A method for manufacturing a tank construction element (1), comprising the steps of:

-providing a secondary insulation structure (2) comprising a support surface,

-providing a plurality of primary insulation blocks (3),

-positioning a spacer (21, 46, 47) in an insertion position in which it is interposed between a first primary insulating block of the plurality of primary insulating blocks (3) and a second primary insulating block of the plurality of primary insulating blocks (3), so that the spacer (21, 46, 47) keeps the spacing between the first and the second primary insulating blocks within a tolerance range,

-fixing the primary insulating block onto the supporting surface of the secondary insulating structure (2), keeping the spacer (21, 46, 47) in the insertion position so that the spacing between the first and second primary insulating blocks is kept within the tolerance range when fixing the first and second primary insulating blocks, and

-removing the spacer (21, 46, 47) from the insertion position after fixing the primary insulating block on the supporting surface.

2. The manufacturing method according to claim 1, further comprising:

-applying an adhesive to one of the support surface and a face of the primary insulating block intended to rest on the support surface, before fixing the primary insulating block onto the support surface, and

-exerting a pressure on one of the primary insulating block and the secondary insulating structure towards the other one of the primary insulating block and the secondary insulating structure to fix the primary insulating block to the secondary insulating structure while keeping the spacer (21, 46, 47) in the interposed position.

3. The manufacturing method according to claim 2, further comprising the steps of:

-providing a positioning device (19), the positioning device (19) comprising a frame (20) and a spacer (21), the frame (20) having a bearing surface (22), the spacer (21) protruding from the bearing surface (22) of the frame (20) such that the bearing surface (22) has a first bearing part (30) and a second bearing part (30) on either side of the spacer (21),

-arranging the positioning means (19) on the primary insulating block (3) so that the first bearing portion (30) rests on the first primary insulating block and the second bearing portion (30) rests on the second primary insulating block, the step of exerting pressure on the first and second primary insulating blocks comprising pressing the first bearing portion (30) onto the first primary insulating block and the second bearing portion (30) onto the second primary insulating block.

4. A manufacturing method according to claim 1 or 2, wherein the primary insulating block has a primary insulating plate (12, 13) and a metal plate (14), the metal plate (14) having an edge (17) projecting beyond the primary insulating plate (12, 13), the method further comprising the steps of:

-providing a positioning device (19), the positioning device (19) comprising a frame (20) and the spacer (21), the spacer (21) comprising two fixing means (31),

and wherein the step of positioning the spacer (21) in the insertion position comprises fixing the projecting edge (17) of the first primary insulating block and the projecting edge (17) of the second primary insulating block to the spacer (21) by respective fixing means (31) of the spacer (21).

5. A manufacturing method according to claim 1 or 2, wherein the spacer comprises a support (46) and a pair of clamps (47) arranged on the support (46) at a predetermined pitch (51), the clamps (47) comprising a setting device (48) and two movable protrusions (49), the setting device (48) being capable of displacing both protrusions simultaneously and by the same distance in opposite directions to define the pitch of the protrusions, the method further comprising the steps of:

-entering the first primary insulation block into one of the clamps (47), then setting the position of the protrusion (49) of the clamp (47) such that the first primary insulation block is fixed in the clamp (47), and

-entering the second primary insulation block into the other one of the clamps (47), and then setting the position of the protrusion (49) of the clamp (47) such that the second primary insulation block is fixed in the clamp (47) and such that the mid-plane of the first primary insulation block is spaced apart from the mid-plane of the second primary insulation block by a spacing within a tolerance range.

6. Manufacturing method according to any one of claims 1 to 5, wherein the step of fixing the primary insulating block (3) onto the supporting surface of the secondary insulating structure (2) comprises the steps of: positioning the spacer (21, 46, 47) with respect to an end of the secondary insulation structure (2).

7. The manufacturing method according to any one of claims 1 to 6, further comprising the steps of:

-providing a plurality of spacers (21, 46, 47),

-positioning each spacer (21, 46, 47) of the plurality of spacers (21, 46, 47) in an insertion position in which each spacer is interposed between two adjacent primary insulation blocks of the plurality of primary insulation blocks (3) such that the spacers (21, 46, 47) keep the spacing between the adjacent primary insulation blocks within a tolerance range, the spacers (21, 46, 47) being interposed between the adjacent primary insulation blocks,

-fixing the primary insulating blocks to the supporting surface of the secondary insulating structure (2), keeping the spacers (21, 46, 47) in the interposed position to keep the spacing between adjacent primary insulating blocks within a tolerance range when fixing them; and

-removing the spacer (21, 46, 47) from the insertion position.

8. Manufacturing method according to claim 7, further comprising the step of providing a positioning device (19), said positioning device (19) comprising a frame (20) and a plurality of spacers (21), said spacers (21) of said plurality being arranged at regular intervals on said frame.

9. Manufacturing method according to any one of claims 6 to 8, wherein the support surface has a first support surface portion and a second support surface portion forming corner portions, a first spacer of the plurality of spacers (21, 46, 47) being positioned in the following insertion positions: in such an insertion position, the first spacer is interposed between two adjacent primary insulating blocks positioned on the first supporting surface portion, and a second spacer of the plurality of spacers (21, 46, 47) is positioned in the following insertion position: in such an insertion position, the second spacer is interposed between two adjacent primary insulating blocks positioned on the second supporting surface portion, the method further comprising the step of fixing the first and second spacers together with displacement.

10. The manufacturing method according to any one of claims 1 to 8, further comprising: -fixing the spacer and the primary insulating block (3) together such that the primary insulating block (3) and the spacer form an assembly that is fixed together in the event of a displacement.

11. Manufacturing method according to any one of claims 1 to 10, wherein the spacer (21, 46, 47) is made of a material selected from wood and polymeric materials, such as high density polyethylene, polytetrafluoroethylene.

12. Manufacturing method according to any one of claims 1 to 11, wherein the spacer (21, 46, 47) is displaced in a plane defined by a gap between two primary insulating blocks (3) in which the spacer (21, 46, 47) is interposed, in order to remove the spacer (21, 46, 47).

13. A positioning device (19) for positioning a primary insulation block of a sealed and thermally insulating tank structural element (1), the structural element comprising a secondary insulation block (2) and a plurality of primary insulation blocks (3), the secondary insulation block (2) having a support surface and the primary insulation blocks (3) being intended to rest on the support surface, the positioning device comprising a frame and a plurality of spacers (21, 46, 47), the plurality of spacers (21, 46, 47) being arranged on the frame along a longitudinal direction of the frame, the plurality of spacers (21, 46, 47) protruding from the frame in a parallel manner in a direction at right angles to the longitudinal direction of the frame, the spacers (21, 46, 47) defining a predetermined spacing in the predetermined longitudinal direction of the frame, and the spacers (21, 47), 46. 47) for being interposed between two adjacent primary insulating blocks of the plurality of insulating blocks (3) so as to maintain a predetermined spacing between two adjacent primary insulating blocks of the plurality of insulating blocks (3) in the longitudinal direction of the frame.

14. The positioning device according to claim 13, wherein the spacers (21, 46, 47) are arranged at regular intervals along the frame.

15. The positioning device according to claim 13 or 14, wherein the frame (20) has a cross section of flat shape, the spacer (21) protruding from a plane (22) of the frame (20).

16. The positioning device according to claim 14 or 15, wherein the primary insulating blocks have primary insulating plates (12, 13) and a metal plate (14), the metal plate (14) having an edge (17) protruding beyond the primary insulating plates (12, 13), and wherein the spacer (21) comprises two rails (31), the rails (31) comprising grooves (32), the rails (31) protruding in opposite orientations from the frame (20) so that each groove (32) can accommodate the protruding edge (17) of the respective primary insulating block.

17. Positioning device according to any one of claims 13 to 16, further comprising means for positioning the frame on the secondary insulating structure (2), so as to arrange the spacer (21, 46, 47) at a predetermined position with respect to the secondary insulating structure (2).

18. The positioning device according to claim 13 or 14, wherein said spacers of a plurality of said spacers comprise a pair of clamps (47), said clamps (47) being arranged on a support (46) with a predetermined spacing between said clamps (47), said supports (46) of a plurality of said spacers forming said frame, said clamps (47) comprising a setting device (48) and two movable protrusions (49), said setting device (48) being capable of displacing both said protrusions simultaneously and in opposite directions by the same distance to define the spacing of said protrusions (48).