EP2740987B1 - Isolating and sealing vessel comprising a support leg - Google Patents

Description

The invention relates to the field of the construction of a sealed and insulating tank arranged in a supporting structure, in particular to the construction of a wall of such a tank to accommodate a support foot.

Sealed and thermally insulating tanks can be used in different industries to store hot or cold products. For example, in the field of energy, liquefied natural gas (LNG) is a liquid which can be stored at atmospheric pressure at approximately - 163 ° C in terrestrial storage tanks or in tanks on board floating structures. Such floating structures are in particular LNG carriers for the transport of the product and off-shore installations, known in particular by the acronyms FPSO and FSRU, for the storage, liquefaction or regasification of the product.

In membrane tanks, a layer of corrugated metal sheet is used to make a watertight barrier which also has sufficient elasticity to withstand forces resulting for example from hydrostatic pressure, dynamic pressure in the event of movement of the cargo, and / or temperature variations. However, such a tight barrier and the underlying thermal insulation material are relatively fragile and cannot necessarily support heavy equipment to be submerged at the bottom of the tank, for example a pump.

KR20080072387 discloses a sealed and insulating tank as defined in the preamble of claim 1.

According to one embodiment, the invention provides a sealed and insulating tank as defined in claim 1.

According to other advantageous embodiments, such a tank may have one or more of the following characteristics.

According to one embodiment, the support foot is centered at a position situated between the guiding lines (A) of the two parallel corrugations of the plurality of parallel corrugations.

The support foot can have various shapes, in particular depending on the characteristics of the equipment to be supported. According to one embodiment, the support foot has at least one convex lateral side, and the guideline of said two corrugations between which the support foot is centered intersects the convex lateral side of the support foot. According to one embodiment, the support foot has a circular section.

According to one embodiment, the window interrupts the guidelines of an even number of parallel corrugations of said at least one series, for example of two parallel corrugations of said at least one series.

According to one embodiment, the support foot is centered substantially in the middle of the guidelines of the two corrugations. As a variant, the support foot can be offset from the middle, so as to be closer to one corrugation than the other, for example if such a positioning makes it possible to reduce the length of interruption of the corrugations given the shape of the support leg.

According to one embodiment, said at least one series of parallel corrugations is distributed equidistantly. Alternatively, the series of corrugations may have, at least locally, a less even distribution.

According to one embodiment, the corrugations project from the side of an internal face of the sealing barrier intended to be in contact with a fluid.

According to one embodiment, the connecting pieces comprise a plurality of end pieces arranged at a distance from the support foot so as to close the interrupted ends of the two corrugations between the guidelines of which the support foot is centered. By such end pieces, it is possible to close all the corrugations, the window of which interrupts the guidelines, so as to re-establish the continuity of the watertight barrier.

According to one embodiment, the support foot comprises a hollow casing of generally tubular shape, the longitudinal axis of which is substantially perpendicular to the tank wall and a transverse closing wall closing the casing in a leaktight manner. to achieve the continuity of the sealing barrier at the level of the support foot. Such a hollow shape may in particular be preferred in order to limit the effective section of the support foot capable of creating a thermal bridge.

The connecting pieces intended to connect the support foot in a sealed manner to a marginal portion of the layer of corrugated metal sheet can have many shapes.

According to one embodiment, the connecting pieces comprise an annular plate connected to a peripheral wall of the support foot at the level of the corrugated metal sheet layer. Such a plate can be pre-assembled to the support leg.

According to one embodiment, the connecting pieces comprise an intermediate plate having a first edge welded to the annular plate and a second edge welded to the marginal portion of the corrugated metal sheet layer delimiting the window.

Such a tank may have a single sealing barrier or multiple successive sealing barriers, for example for reliability and safety reasons. According to a corresponding embodiment, the thermal insulation barrier comprises a primary thermal insulation barrier arranged on the side of the sealing barrier, called the primary sealing barrier, and a secondary thermal insulation barrier arranged on the side of the supporting structure, the vessel wall comprising a secondary sealing barrier arranged between the primary and secondary thermal insulation barriers, the secondary sealing barrier being connected in a sealed manner to a peripheral wall of the support foot.

According to one embodiment, the connecting parts comprise:
a link plate having a corrugation parallel to said at least one series of parallel corrugations and disposed on a line offset laterally at a distance from the support foot with respect to one of the corrugation guidelines interrupted by the window and
deflection pieces arranged so as to connect each time one end of the corrugation of the connecting plate to an end portion of the corrugation whose direct line is interrupted by the window, so that the corrugation of the connecting plate and the two deflection pieces extend the corrugation, the guideline of which is interrupted in a sealed manner through the window by following the line offset laterally at a distance from the support foot. The production of one or more corrugations offset in this way makes it possible to limit the number of corrugations made discontinuous by the support foot, and therefore to further preserve the elasticity of the waterproof barrier, in particular in the case where a support foot of relatively large diameter must be put in place.

The arrangements and characteristics stated above with respect to a series of parallel corrugations can, where appropriate, be applied with respect to several series of parallel corrugations having different directions. According to a corresponding embodiment, the corrugated metal sheet layer has a first series of parallel corrugations and a second series of parallel corrugations which intersects the first series of parallel corrugations at the level of crossings, the window interrupting the lines. guiding a first plurality of the parallel corrugations of the first series and / or the guiding lines of a second plurality of the parallel corrugations of the second series, the support foot being centered at a position between the guiding lines of two parallel corrugations of the first plurality and / or between the guidelines of two parallel corrugations of the second plurality.

According to a preferred embodiment, the first series of parallel corrugations is perpendicular to the second series of parallel corrugations. Thus the elasticity of the waterproof membrane can be well balanced in different directions.

The aforementioned window can have different shapes, in particular depending on the shape of the support foot and / or the shape of the constituent elements of the corrugated metal sheet layer. According to one embodiment, the window is a quadrilateral, for example rectangle or square or parallelogram, comprising two sides parallel to the first series of corrugations and two sides parallel to the second series of corrugations.

According to one embodiment, the support foot is arranged at the base of a mast for unloading the tank, for example to support a pump.

An idea at the basis of the invention is to support equipment to be immersed in a tank on a foot bearing directly or indirectly on the supporting structure, to avoid or limit a force exerted on a relatively fragile corrugated waterproofing membrane. Another idea at the basis of the invention is to have such a support foot in a way which does not jeopardize the essential mechanical properties of the corrugated waterproofing membrane, in particular its tightness and its resistance to thermal contraction. or to pressure efforts. Certain aspects of the invention are based on the idea of interrupting undulations of a corrugated waterproofing membrane at the level of a passage zone of a support foot, and of positioning this support foot at a location which makes it possible to limit the length of these interruptions, in order to limit the loss of elasticity of the membrane which may result from such interruptions. Other aspects of the invention start from the idea of locally displacing corrugations in order to bypass the zone of passage of the support foot without interrupting these undulations.

The invention will be better understood, and other aims, details, characteristics and advantages thereof will emerge more clearly during the following description of several particular embodiments of the invention, given solely by way of illustration and not by way of limitation. , with reference to the accompanying drawings.

• La figure 1 est une représentation schématique partielle en coupe d'une cuve étanche et isolante selon un mode de réalisation,
• La figure 2 est une représentation en perspective, en section transversale selon la ligne II-II de la figure 3, d'un pied de support et d'une structure de paroi de cuve ne représentant pas l'invention pouvant être utilisés dans la cuve de la figure 1,
• La figure 3 est une vue de dessus du pied de support de la figure 2 et d'une zone de la paroi de cuve ne représentant pas l'invention autour du pied de support,
• La figure 4 est une représentation analogue à la figure 2 à un stade intermédiaire de montage de la paroi de cuve,
• La figure 5 est une vue de détail agrandie de la zone V de la figure 4,
• La figure 6 est une vue de dessus de la zone de paroi de cuve de la figure 4 montrant la réalisation de la barrière d'étanchéité secondaire,
• La figure 7 est une vue analogue à la figure 6 montrant un stade intermédiaire de montage de la barrière d'étanchéité primaire,
• La figure 8 est une vue en perspective d'une pièce de bout pouvant être utilisée dans la fabrication de la barrière d'étanchéité primaire,
• La figure 9 est une vue analogue à la figure 3 représentant un mode de réalisation selon l'invention de la barrière d'étanchéité primaire autour du pied de support,
• La figure 10 est une vue en perspective d'une pièce de dévoiement pouvant être utilisée dans la fabrication de la barrière d'étanchéité primaire de la figure 9.

On these drawings:

• The figure 1 is a partial schematic representation in section of a sealed and insulating tank according to one embodiment,
• The figure 2 is a perspective representation, in cross section along the line II-II of the figure 3 , a support foot and a vessel wall structure not representing the invention that can be used in the vessel of the figure 1 ,
• The figure 3 is a top view of the support leg of the figure 2 and a zone of the tank wall not representing the invention around the support foot,
• The figure 4 is a representation analogous to the figure 2 at an intermediate stage of assembly of the tank wall,
• The figure 5 is an enlarged detail view of zone V of the figure 4 ,
• The figure 6 is a top view of the vessel wall area of the figure 4 showing the construction of the secondary waterproofing barrier,
• The figure 7 is a view similar to the figure 6 showing an intermediate stage of assembly of the primary waterproofing barrier,
• The figure 8 is a perspective view of an end piece that may be used in the manufacture of the primary sealing barrier,
• The figure 9 is a view similar to the figure 3 showing an embodiment according to the invention of the primary sealing barrier around the support foot,
• The figure 10 is a perspective view of an offset piece that may be used in the fabrication of the primary sealing barrier of the figure 9 .

On the figure 1 , we partially see a sealed and thermally insulating tank 1 consisting of tank walls 2 and 3 fixed to the inner surface of corresponding walls 4 and 5 of a supporting structure. The supporting structure is for example the inner hull of a double-hull ship or a construction located on land. To contain a cold liquid such as LNG, the walls of the tank include at least one sealing barrier 6 and at least one thermal insulation barrier 7. For safety reasons, it is possible to provide a secondary sealing barrier. , not shown, between the supporting structure and the sealing barrier 6, which is called primary in this case.

The tank 1 can be produced according to various well-known geometries, for example a prismatic geometry in the hull of a ship or a cylindrical geometry on land or the like. Furthermore, many methods are available for producing thermal insulation and sealing barriers, for example from prefabricated elements.

In the bottom wall 3 of the tank, there is shown an elongated rigid element, constituting a support foot 10, which extends through the thermal insulation barrier 7 and the sealing barrier 6, so that one end rests against the bottom wall 5 of the supporting structure and the other end projects into the tank at a distance from the sealing barrier 6. The support foot 10 can for example be used to support equipment 9 in front of be submerged in the tank. For example, to support an unloading pump, it can be placed at the base of a pump mast of the tank, not shown. Although the support foot is here shown on a bottom wall of the tank, a similar rigid element can be arranged in the same way at other locations in the tank, for example as a support or spacer element to hold any object at a distance from the tank wall.

To achieve the sealing barrier 6, it is possible to use thin metal sheet plates having corrugations which form elastic zones to absorb thermal contraction and static and dynamic pressure forces. Such corrugated or embossed sheet metal sealing barriers have in particular been described in FR-A-1379651 , FR-A-1376525 , FR-A-2781557 and FR-A-2861060 . This possibility will now be developed with reference to figures 2 and 3 .

With reference to the figure 3 , the sealing barrier 6 consists of a plurality of corrugated sealed plates 11, the so-called internal face of which is intended to be in contact with the fluid. The waterproof plates 11 are thin elements made of metal such as stainless steel or aluminum sheet and are welded together at the level of marginal overlap areas 12. The welds are of the overlap weld type, the process of which is described. in detail for example in the patent FR-A-1387955 . The sealing plates 11 can be designed in various ways as to their shapes and dimensions, so that the weld areas can be variously positioned.

The sealed plates 11 comprise, on their internal face, a first series of so-called longitudinal corrugations 15 and a second series of so-called transverse corrugations 16, the respective directions of which are perpendicular. The first series of corrugations 15 has a height less than the second series of corrugations 16. Thus, the corrugations 15 are discontinuous at their crossings 18 with the corrugations 16 which are. continues. The longitudinal 15 and transverse 16 corrugations project towards the interior of the tank 1.

The support foot 10 has here a shape of revolution with a circular section, with a frustoconical lower part 13 which connects at its end of smaller diameter 17 to a cylindrical upper part 14. The base of larger diameter of the part frustoconical 13 bears against the wall 5 of the supporting structure. The frustoconical part 13 extends through the thickness of the vessel wall beyond the level of the sealing barrier 6. The cylindrical part 14 is closed in a sealed manner by a circular plate 19, which may for example be welded to an inner rim, not shown, of the cylindrical part 14.

To allow the passage of the support foot 10, the corrugated waterproof plates 11 forming the waterproofing barrier 6 are cut so as to delimit a square window 25 around the support foot 10. To achieve the continuity of the waterproofing barrier 6 at the level of the window 25, a sealed assembly of connecting pieces is produced between the support foot 10 and the waterproof plates 11. As the diameter of the support foot 10 is greater than the spacing between the corrugations of the first series 15 , some of the longitudinal corrugations indicated in numeral 20 and whose direct line A intersects the support foot 10 have been interrupted at the level of the window 25. Likewise, as the diameter of the support foot 10 is greater than the spacing between the supports. corrugations of the second series 16, some of the transverse corrugations indicated in numeral 21 and of which the guideline B intersects the support foot 10 have been interrupted at the level of the window surrounding the pi support ed.

Moreover, as visible on the figure 3 , the size of the window 25 is in practice larger than the diameter of the support foot 10, so that the fitting of the connecting pieces is relatively easy. Thus, the window 25 formed in the layer of corrugated sheet would be capable of similarly interrupting undulations, the guideline of which, without actually cutting the support foot, would be located too close to the support foot to allow the installation. connecting pieces between them and the support foot.

The center C of the support foot 10 is positioned between the guidelines A of the interrupted undulations 20 and between the guidelines B of the interrupted undulations 21, and more precisely in the middle of these guidelines on the figure 3 . The result of this positioning is that the directing line A or B each time cuts the support foot 10 along a chord shorter than the diameter of the support foot 10. As a result, and taking into account the space that must exist between the edge of the window 25 and the support foot 10 for allow the establishment of the connecting pieces, this positioning of the support foot makes it possible to interrupt each of the corrugations 20 and 21 over a shorter distance than in the case where the guideline A or B would cut the support foot according to its most large transverse dimension, that is to say its diameter in the case of a circular section. It is advantageous to interrupt the corrugations of the sealing barrier over the shortest possible distance, given that these interruptions are liable to locally reduce the flexibility of the sealing barrier and therefore locally promote its fatigue and wear. .

In the case of a circular section, the centering of the support foot halfway between the interrupted corrugations 20 and halfway between the interrupted corrugations 21 offers an optimal result. However, other forms of section and other positioning of the foot can also be considered. A principle that can be used to adapt the positioning of the support foot between the corrugations each time is to choose a position which minimizes, or at least decreases, the transverse dimension of the support foot cut by the guideline of the interrupted corrugation. In the event that the particular geometry of the support foot and / or the particular distribution of the corrugations of the membrane involves interrupting several undulations over different lengths, a relevant optimization parameter to adapt the positioning of the support foot may be the length of the longest interrupt or the cumulative length of the interrupts obtained.

On the figure 3 , the window 25 has a square shape which facilitates the cutting of the waterproof plates 11 to the desired shape. However, other forms of windows can also be implemented, depending in particular on the geometry of the support foot.

With reference to figures 4 to 8 , we will now describe a detailed embodiment of the tank wall in the area of the support foot 10. This embodiment is particularly suitable for a tank whose walls have two sealing barriers and two insulation barriers. thermal. The barrier 6 will therefore be qualified as a primary sealing barrier. Only the vicinity of the support foot 10 will be described, the vessel walls also being able to be produced in accordance with the teaching of the application. FR-A-2781557 .

The figure 4 is a half-sectional view of the support foot 10 and an area of the substantially square vessel wall around it at an intermediate stage of assembly. The right part is shown before the installation of the elements of the secondary sealing barrier and of the primary insulation barrier, the left part after the installation of these elements.

To connect to the secondary sealing barrier, the support foot 10 comprises a secondary plate 23 of square shape fixed around the frustoconical part 13 to a height corresponding to the upper surface of the secondary thermal insulation barrier 22 and of the secondary waterproof barrier which is very thin. To connect to the primary waterproofing barrier, the support foot 10 comprises a primary plate 24 of round shape fixed around the frustoconical part 13 at a height corresponding to the upper surface of the primary thermal insulation barrier 26. The plates 23 and 24 can be made in one piece with the support foot 10.

Below the secondary tray 23, the secondary insulation barrier 22 has a glass wool stuffing 27 which also has a square outer contour. Below the primary tray 24, the primary insulation barrier 26 has a glass wool stuffing 28 which also has a circular outer contour.

Around the stuffing 27 and the plate 23, the secondary insulation barrier, the secondary waterproofing barrier and the primary insulation barrier are made by means of four corner panels, one of which is visible on the right side. of the figure 4 at number 30. A panel 30 has an overall shape of L-shaped steps with a lower L-shaped insulating block 31 constituting an element of the secondary insulation barrier 22, a flexible waterproof covering 32 completely covering the upper surface in L-shaped block 31, and a smaller L-shaped upper insulating block 33 constituting an element of the primary insulation barrier 26. The upper block 33 is aligned with the outer sides of the lower block 31, so as to leaving uncovered an area of the waterproof covering 32 located on an inner rim and on end rims of the lower block 31. The panel 30 may be prefabricated by gluing with materials similar to those taught in the application. FR-A-2781557 including polyurethane foam and plywood for the insulation barriers and a composite material of aluminum foil and fiberglass for the secondary waterproofing barrier.

The four corner panels 30 border on their inner sides the contour of the stuffing 27 and of the plate 23. The dimensions of the blocks 31 are designed to leave spaces between them in the form of four radial chimneys 34 located each time between the faces. end of two neighboring lower blocks 31. To ensure continuity of the primary insulation barrier 22, each of the chimneys 34 is stuffed with a sheet of fiberglass 35. The porosity of the fiberglass of the sheets 35 and of the stuffing 27 makes it possible to circulate gas through it. through the primary insulation barrier 22, in particular for inerting the tank wall with nitrogen.

The figure 6 shows the construction of the secondary sealing barrier in the area of the support foot 10 in top view. To achieve the continuity of the barrier secondary sealing around the support foot 10, four strips 36 of the waterproof composite material of aluminum foil and fiberglass are glued on the secondary plate 27 and on the waterproof coating 32 of the panels 30. A strip 36 is positioned at each time so as to overlap one side of the secondary plate 27 and the inner edges uncovered of two lower blocks 31. The bands 36 overlap at the level of end zones 37. To achieve the continuity of the secondary sealing barrier at the same time. above the chimneys 35, four strips 38 of waterproof composite material made of aluminum foil and fiberglass are glued to the waterproof covering 32 of the panels 30, each time so as to overlap the end edges of two lower blocks 31.

The figure 7 represents the same area of the tank wall after installation of the primary insulation barrier. This is completed between the upper insulating blocks 33 and the support foot 10 by means of four corner blocks 40 and four middle blocks 41, the inner side of which each time matches the rounded contour of the primary plate 24 and of the jam 28. These blocks 40 and 41 are also represented on the left part of the figure 4 .

As visible on the detail of the figure 5 , the upper surface of the median blocks 41 has in each case a rebate 44 delimited by a recess 43. The rebates 44 are precisely at the level of the primary plate 24 to provide a flat support surface for metal closure plates 45 intended to achieve the primary sealing barrier around the support leg 10.

As visible on the figure 7 , two closure plates 45 are arranged around the primary plate 24 and sealed to the latter over its entire periphery. For this, the plates 45 are cut in a semicircle at their inner edge 46, while their outer edge 47 defines a square with a dimension slightly greater than the window 25 formed in the corrugated waterproof plates 11. The two closure plates 45 overlap at areas 48 where they are welded together. The closure plates 45 are fixed to the blocks 40 and 41 of the primary insulation barrier by means of wood screws or rivets 49 arranged near their outer edge 47 in order to firmly press the closure plates 45 against these blocks, in particular because it is necessary to avoid that they do not rise while they are welded on the primary plate 24.

Back on the figures 2 and 3 , it can be seen that the primary sealing barrier 6 in the area of the support foot 10 is completed, on the one hand by welding the edges of the sealing plates 11 delimiting the window 25 on the closure plates 45, and on the other hand by sealingly closing the ends of the interrupted corrugations 20 and 21 with end pieces 50. The sealing plates 11 are cut so as to cover the edge of the closure plates 45 comprising the screws 49.

An exemplary embodiment of an end piece 50 is shown in figure 8 . The end piece 50 comprises a sole in two parts 51 and 52 intended to be welded in a sealed manner respectively on the closure plate 45 and on the waterproof plate 11, and a shell 54 intended to be welded in a sealed manner at the end. of the corrugation 20 or 21. A recess 53 between the parts 51 and 52 of the sole has an amplitude substantially equal to the thickness of the waterproof plate 11.

The cutting of the insulating blocks and other prefabricated elements shown on the figures 2 , 4 , 6 and 7 to constitute the secondary insulation barrier, the secondary sealing barrier and the primary insulation barrier is purely illustrative. Similar elements can be cut and prefabricated in other shapes so that the mounting of the tank wall involves a higher or lower number of elementary parts. According to other corresponding embodiments, the four L-shaped corner panels 30 are replaced by two U-shaped panels or a single panel having the shape of a square frame.

As best seen on the figure 3 , the support foot considered above requires a window of size approximately equal to twice the spacing 55 between two corrugations 15 or 16, which are equidistant here. For this, two waves of each series were interrupted. However, this arrangement of the support foot and of the tank wall in its vicinity can be adapted to other dimensions of the support foot. For example, for a wider support leg, the corresponding window may interrupt a greater number of corrugations in one or each series, for example three or four or more corrugations. In addition, it is also possible to locally move the path of certain corrugations to limit the number of corrugations to be interrupted, and thus preserve a higher level of elasticity of the waterproofing membrane. This possibility is illustrated by the embodiment of the figure 9 .

On the figure 9 , the elements identical or similar to those of the figure 3 bear the same reference number increased by 100. The transverse dimension of the support foot 110 being greater, for example greater than or equal to approximately three times the spacing 155 between the corrugations 115 or 116, the window 125 formed in the metal membrane corrugated for the passage of the foot 110 interrupts in this case the guidelines of four respective corrugations in each series. However, instead of interrupting four waves in each series, this embodiment provides for interrupting two corrugations 120, respectively 121, of each series as in the previous embodiment, while the other two corrugations 158, respectively 159 of each series are locally offset at a distance from the support foot 110 with respect to their original guideline, but not are ultimately not interrupted.

For this, the sealing barrier 106 is modified at the level of two concentric square windows 125 and 160. Outside the window 160, the sealing barrier 106 consists of sealed plates 111 carrying longitudinal 115 and transverse corrugations. 116 distributed equidistantly. Between window 160 and window 125, sealing barrier 106 is continued with other corrugated sealing plates, i.e. two generally C-shaped plates 161 in the present case, which carry distributed corrugations. differently, that is to say less spaced in this case. The corrugations of the plates 161 in particular constitute a central segment 162, respectively 163, offset at a distance from the support foot 110, for each of the corrugations 158, respectively 159. Finally, the structure of the sealing barrier 106 at the level of the window 125 and inside thereof is similar to the embodiment of the figure 3 .

To make the junction at the level of the window 160 between the central segment 162 or 163 of the corrugation 158 or 159 and the portions of the corrugations located outside the window 160, offset pieces 170 are used.

An exemplary embodiment of an offset part 170 is shown in figure 10 . The offset part 170 comprises a flange in two parts 171 and 172 intended to be welded in a sealed manner respectively to a plate 111 or 161 of the sealing barrier 106 and to an adjacent offset part 170, and an angled corrugation 174 of which the guideline forms a chosen angle, for example 135 °. The bent corrugation 174 is intended to be connected in a sealed manner to the adjacent end of the corrugation 158 or 159 and to the bent corrugation of the adjacent deflection part. A step 173 between the parts 171 and 172 of the sole has an amplitude substantially equal to the thickness of the sheet used to make the waterproof plates 111 or 161 or the offset pieces 170. Preferably, a sheet of the same thickness is used. for these different parts.

In another embodiment not shown, suitable for example for a support foot of smaller diameter, all the corrugations of which the window interrupts the guideline, for example two corrugations of each series as on the figure 3 , are extended through the window in an offset path, similar to the undulations 158 and 159 of the figure 9 . In this embodiment, the flexibility of the membrane can be improved since no ripple is ultimately interrupted by an end piece at the support leg.

In the embodiments described above, the primary sealing barrier is made of sheet metal comprising two series of mutually perpendicular corrugations. However, other types of corrugated metal membranes with less or more corrugations and / or a different arrangement of the corrugations can be similarly employed.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it comprises all the technical equivalents of the means described as well as their combinations if these come within the scope of the invention as defined by the claims.

The use of the verb “comprise”, “understand” or “include” and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim. The use of the indefinite article "a" or "a" for an element or a stage does not exclude, unless otherwise stated, the presence of a plurality of such elements or stages. Several means or modules can be represented by the same hardware element.

In the claims, any reference sign in parentheses cannot be interpreted as a limitation of the claim.

Claims (19)

1. Sealed and insulative tank disposed in a support structure, the tank including a tank wall (3) disposed along the support structure (4), the tank wall including:

   a sealing barrier (6, 106),

   a thermal insulation barrier (7, 22, 26) disposed between the sealing barrier and the support structure and having a support surface for the sealing barrier, and

   a pedestal (10, 110) for equipment immersed in the sealed tank,

   the sealing barrier including a layer of corrugated sheet metal (11, 111) having at least one series of parallel corrugations (15; 115), the layer of corrugated sheet metal being interrupted by a window (25, 125) around the pedestal,

   the pedestal extending longitudinally through the window in the layer of corrugated sheet metal and having a first end portion bearing against the support structure and a second end portion projecting into the tank to support the equipment at a distance from the sheet metal layer,

   the sealing barrier including connecting parts (24, 45, 50) disposed in the window around the pedestal to join the pedestal in sealed manner to a marginal portion of the layer of corrugated sheet metal delimiting the window,

   wherein the window (25, 125) interrupts the directrices of a plurality (20, 120, 158, 159) of the parallel corrugations of said at least one series, the tank being characterized in that said plurality of parallel corrugations includes two corrugations (158,159) offset locally at a distance from the pedestal (10) relative to their directrices such that said two corrugations were not interrupted by the pedestal (10)
2. Tank according to Claim 1, wherein the pedestal is centred at a position situated between the directrices (A) of two parallel corrugations of said plurality (20, 120, 158, 159) of parallel corrugations.
3. Tank according to Claim2, wherein the pedestal has at least one convex lateral side (13),
   the directrices of the two corrugations (20, 120) between which the pedestal is centred intersecting the convex lateral side of the pedestal.
4. Tank according to any of Claims 1 to 3, wherein the plurality (20, 120, 158, 159) of parallel corrugations, the directrices of which are interrupted by the window (25,125), includes at least three corrugations.
5. Tank according to Claim 3, wherein the plurality (20, 120, 158, 159) of parallel corrugations, the directrices of which are interrupted by the window (25,125), includes at least a corrugation interrupted by the pedestal (110).
6. Tank according to any of Claims 1 to 5, wherein the pedestal is centred substantially in the middle of the directrices of the two corrugations.
7. Tank according to any of Claims 1 to 6, wherein the pedestal has a circular cross section.
8. Tank according to any of Claims 1 to 7, wherein said at least one series of parallel corrugations (15, 115) is equidistantly distributed.
9. Tank according to any of Claims 1 to 8, wherein the corrugations (15; 115) project on the side of an internal face of the sealing barrier intended to be in contact with a fluid.
10. Tank according to any of Claims 1 to 9, wherein the connecting parts include a plurality of end parts (50, 150) disposed at a distance from the pedestal in such as manner as to close interrupted ends of the corrugations (20, 120) interrupted by the pedestal.
11. Tank according to any of Claims 1 to 10, wherein the pedestal includes a hollow envelope (13, 14) of generally tubular shape the longitudinal axis of which is substantially perpendicular to the tank wall and a transverse closure wall (19) closing the envelope in sealed manner to produce the continuity of the sealing barrier at the level of the pedestal.
12. Tank according to any of Claims 1 to 11, wherein the connecting parts include an annular plate (24) joined to a peripheral wall of the pedestal at the level of the layer of corrugated sheet metal (11, 111).
13. Tank according to any of Claims 1 to 12, wherein the connecting parts include an intermediate plate (45, 145) having a first edge welded to the annular plate and a second edge welded to the marginal portion of the corrugated sheet metal layer (11, 161) delimiting the window.
14. Tank according to any of Claims 1 to 13, wherein the thermal insulation barrier includes a primary thermal insulation barrier (26) disposed on the side of the sealing barrier (6), referred to as the primary sealing barrier, and a secondary thermal insulation barrier (22) disposed on the side of the support structure, the tank wall including a secondary sealing barrier (23, 32, 36, 38) disposed between the primary and secondary thermal insulation barriers, the secondary sealing barrier being joined in sealed manner to a peripheral wall (13) of the pedestal.
15. Tank according to any of Claims 1 to 14, wherein the connecting parts include:
    a connecting plate (161) having a corrugation (162) parallel to said at least one series of parallel corrugations (115) and disposed on a line offset laterally from the pedestal relative to one of the directrices interrupted by the window, and bend parts (170) disposed in such a manner that each joins one end of the corrugation of the connecting plate to an end portion of the corrugation (158) the directrix of which is interrupted by the window so that the corrugation (162) of the connecting plate and the two bend parts extend the corrugation (158) the directrix of which is interrupted in sealed manner across the window along the line offset laterally from the pedestal (110).
16. Tank according to any of Claims 1 to 15, wherein the corrugated sheet metal layer includes a first series of parallel corrugations (15, 115) and a second series of parallel corrugations (16, 116) that intersects the first series of parallel corrugations at crossing points, the window interrupting the directrices of a first plurality of parallel corrugations of the first series and/or the directrices of a second plurality of parallel corrugations of the second series, each of the plurality of parallel corrugations of the first and of the second series includes two corrugations (158,159) offset locally at a distance from the pedestal (10) relative to one of their directrices such that said two corrugations were not interrupted by the pedestal (10).
17. Tank according to Claim 16, wherein the first series of parallel corrugations is perpendicular to the second series of parallel corrugations.
18. Tank according to Claim 16 or 17, wherein the window (25, 125) is a quadrilateral having two sides parallel to the first series of corrugations and two sides parallel to the second series of corrugations.
19. Tank according to any of Claims 1 to 18, wherein the pedestal (10, 110) is disposed at the base of a mast for discharging the tank.

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