BRPI0920667B1 - WATERPROOF CUBA AND FLOATING CONSTRUCTION - Google Patents

Abstract

watertight vat and floating construction the present invention relates to a watertight and thermally insulated vat, from which at least one wall comprises a watertight membrane intended to be in contact with the product contained in the vat and a thermally insulating layer adjacent to the membrane, in which the membrane comprises at least one plate (1) with at least one corrugation (2, 3), characterized by the fact that it comprises a reinforcement element (5), inserted under the corrugation, between the membrane and the thermally insulating layer.

Description

Descriptive Report of the Invention Patent for WATERPROOF CUBA AND FLOATING CONSTRUCTION.

Technical domain of the invention [0001] The present invention relates to a watertight tank. In particular, the present invention relates to a watertight and thermally insulated tank for the transportation of liquefied natural gas (LNG) by ship.

State of the art [0002] FR 2 781 557 describes a tank integrated in the structure of a ship, which allows the transport of LNG. The vat walls successively comprise, from the inside of the vat to the outside, a primary watertight barrier, a primary thermally insulating barrier, a secondary watertight barrier and a thermally secondary barrier. The primary watertight barrier is a membrane made of corrugated metal plates, made of stainless steel. More precisely, each plate has a series of waves parallel to the ship's axis and another series of waves perpendicular to the ship's axis.

[0003] In operation, mechanical stresses are generated on the membrane. These efforts have several sources: the thermal retraction when the tank is cold placed, the effect of the ship's beam, the hydrostatic pressure due to the loading, as well as the dynamic pressure due to the movement of the loading, notably due to the wave.

[0004] The waves predicted on the metal plates of the membrane are intended to allow the membrane to deform to limit the efforts generated by the thermal retraction and the effect of the ship's beam.

[0005] It was found that the dynamic pressure could cause plastic deformations of the waves. However, in use, these deformations can lead to degradation of the flexibility of the plates and damage to the stan

Petition 870190091678, of 9/13/2019, p. 3/21

2/10 quality of the membrane, notably at the level of the junctions between plates.

[0006] To increase the pressure resistance of the membrane and limit plastic deformations, FR 2 861 060 proposes to provide reinforcement ribs over the corrugations.

[0007] However, it may be interesting to further increase the pressure resistance of the membrane.

Summary of the invention [0008] A problem that the present invention proposes to solve is to provide a bowl that does not present at least certain pre-mentioned drawbacks of the prior art. In particular, one purpose of the invention is to improve the pressure resistance of the membrane, in order to prevent or limit plastic deformations.

[0009] The solution proposed by the invention is a watertight tub, of which at least one wall comprises a watertight membrane intended to be in contact with the product contained in the tub and a support adjacent to the membrane, in which the membrane comprises at least one plate which has at least one corrugation, characterized by the fact that it comprises a reinforcement element inserted under the corrugation, between the membrane and the support.

[00010] It was found that this reinforcement element allows to limit the efforts generated in the membrane. Naturally, the membrane can comprise several plates, the plate can have several waves, and a reinforcement element can be arranged under one or more waves of one or more plates. The support can be, for example, a thermally insulating layer, and more precisely a counter-placed panel of a technically insulating layer.

[00011] According to an embodiment, the reinforcement element has an internal passage that allows the gas to circulate

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3/10 between the corrugation and the support, crossing the reinforcement element. [00012] According to an embodiment, an external passage allows the gas to circulate between the corrugation and the support bypassing the reinforcement element.

[00013] Advantageously, the reinforcement element is made of a material chosen from: the backplate, polyethylene, polycarbonate, glass fiber reinforced polycarbonate, polyether imide, and expanded polystyrene.

[00014] According to an embodiment, the reinforcement element comprises an external envelope, the shape of which corresponds substantially to the shape of the corrugation.

[00015] Preferably, the reinforcement element comprises at least one reinforcement mesh within that wrap.

[00016] Advantageously, in the absence of product contained in the vat, the minimum distance between the reinforcement element and the corrugation is between 0% and 5% of the height of the corrugation.

[00017] Preferably, the plate has a first series of corrugations parallel to each other, and a second series of corrugations parallel to each other and transversal to the corrugations of the first series, the reinforcement element being inserted under a corrugation of the first series. Naturally, several reinforcement elements can be inserted under several corrugations of the first series.

[00018] According to an embodiment, the reinforcement element has a length corresponding to the distance between two corrugations in the second series. As a variant, this length can be shorter or longer.

[00019] Advantageously, the reinforcement element is inserted under the corrugation, in a sliding way, in relation to the membrane and the support. In this case, the manufacture of the vat does not require a step for fixing the reinforcement element.

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4/10 [00020] In a variant, the reinforcement element is fixed to the membrane or the support. This makes it possible to ensure that the reinforcement element remains positioned in the desired location.

[00021] According to one embodiment, the membrane has a counter spoil, the reinforcement element being clipped on, or sheared, against spoil.

[00022] According to an embodiment, at least two reinforcement elements are arranged respectively under two adjacent corrugations of the membrane, one of these two reinforcement elements forming a stop for the other of these two reinforcement elements. Thus, one reinforcement element is held captive by the other and is therefore held in place.

[00023] Advantageously, the reinforcement element has at least one weak point capable of deforming or breaking if it is subjected to an effort above a determined limit.

[00024] This allows to know, through controlled plastic deformations of the membrane, the pressures suffered by the membrane and to identify possible risks of damage to the underlying support.

[00025] Preferably, the distance from the corrugation, the membrane is in contact with the support.

[00026] The invention also provides a floating construction comprising a tank, according to the invention, above. It may be a ship or another type of floating installation.

Brief description of the figures [00027] The invention will be better understood, and other purposes, details, characteristics and advantages of it will appear more clearly during the following description of a particular embodiment of the invention, given only by way of illustration and not limitation, with reference to the attached drawings. In these drawings:

- figure 1 represents a perspective view of a

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5/10 corrugated plate of a vat, according to an embodiment of the invention;

figure 2 represents a perspective and sectional view of a corrugation of the corrugated plate of figure 1, and of a reinforcement element, according to a first variant;

- Figures 3 to 9 represent, in perspective, different variants of the reinforcement element, and

figures 10 and 11 represent, in cross-section, other variants of the reinforcement element;

figure 12 shows a top view of the plate in figure 1, at the level of a corrugation crossing, as well as a perspective and partial section view of a reinforcement element fixed by clipping under a corrugation;

- figure 13 represents a reinforcement element intended to be placed simultaneously under several corrugations; and

figure 14 represents, in an exploded perspective, the reinforcing elements cooperating with each other.

Detailed description of an embodiment of the invention [00028] A vat, according to an embodiment of the invention, can have a multilayer structure in a similar way to the vats of documents FR 2 781 557 and FR 2 861 060 mentioned in the introduction. In particular, the tank has a primary watertight membrane made of corrugated metal plates that rest on a counter-placed panel of a primary thermally insulating layer. The general aspects of this multilayer structure, being known, are described below the particularities of the tank, according to an embodiment of the invention.

[00029] The plate 1 shown in figure 1 is a corrugated plate, made of stainless steel, with a globally rectangular shape. The tank's primary watertight membrane is made by welding edge to edge several times

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6/10 plates of this type.

[00030] As shown in figure 1, plate 1 comprises three large corrugations 2 that extend according to the length of plate 1 and 9 small full corrugations 3 that extend according to the width of plate 1. There is talk of large corrugations 2 and small corrugations 3, because the height of the large corrugations 2 is higher than that of the small corrugations 3.

[00031] As a variant, plate 1 could have a different number of large corrugations 2 and / or small corrugations 3. As a variant, plate 1 corrugations could have reinforcement ribs as described in FR 2 861 060. The waves of plate 1 could also have other configurations, for example, according to documents FR 2 735 847 or KR - 10 - 2005 - 0050170.

[00032] In figure 2, it is seen that the plate 1 rests on the counterplate 4 of the underlying thermally insulating layer. As a variant, plate 1 could rest on another type of support. It can also be seen in this figure that a reinforcement element 5 is arranged under the major corrugation 2, between the plate 1 and the counterplate 4. Within the scope of this description, under means that the reinforcement element 5 is covered by the corrugation, but not it necessarily means that he is lower. In effect, on the vertical walls of the tank, the reinforcement element 5 is located in the horizontal of the corrugation it covers.

[00033] In the example of figure 2, the length of the reinforcement element 5 corresponds to the distance between two small corrugations 3.

[00034] Several reinforcement elements 5 can be arranged, each under a large corrugation 2 between 2 small corrugations 3. The number and distribution of the reinforcement elements 5 can be determined according to the distribution of the foreseen efforts in operationPetition 870190091678, of 09/13/2019, p. 8/21

7/10 ment on the tank membrane.

[00035] As a variant, the length of the reinforcement element 5 can be less than the distance between two small corrugations 3 or, if the geometry of the crossing between corrugations allows, greater than that distance. As a variant, reinforcement elements 5 can be provided under the small corrugations 3.

[00036] The reinforcement element 5 is placed as shown in figure 2, without being fixed either on the plate 1, nor on the counterplate 4. It can, therefore, eventually slide under the great corrugation 2. The manufacture of the bowl does not, therefore, need of step of fixing the reinforcement elements 5. As a variant, the reinforcement element 5 can be fixed on the membrane or on the backplate 4.

[00037] Numerous shapes can be convenient for the reinforcement element 5. Figures 3 to 11 represent different shapes that can be convenient. The views of figures 3 to 9 represent perspective views of the section of the reinforcement element 5, the length of which may be greater than that shown. The views in figures 10 and 11 represent sectional views. In these different figures, the same reference signs are used to designate similar elements.

[00038] The reinforcement element 5 of figure 3 has a full section. Its two side faces 6 are curved and corresponding to that of the corrugation 2. However, the side faces 6 do not extend to the top of the corrugation 2 and the reinforcement element 5 has a flat top face 7. Gas can circulate between the top of the corrugation 2 and the top face 7.

[00039] The reinforcement element 5 of figure 4 has a wrap, the external shape of which corresponds to the shape of the corrugation 2. A circular passage 9 allows the gas to pass through the reinforcement element 5. In the variant of figure 5, the passage 9 has a color shape

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8/10 responding to the external shape of the wrap, in order to offer a larger passage surface.

[00040] The reinforcement element 5 of figure 6 also has a wrap, the external shape of which corresponds to the shape of the corrugation 2 and a passage 9. In order to improve the mechanical resistance of the reinforcement element 5, internal screens 10 pass through the passage 9 Figures 7 to 9 represent alternative configurations of screens 10.

[00041] The reinforcing elements of figures 3 to 9 can be made, for example, in one of the following materials: polyethylene, polycarbonate, glass fiber reinforced polycarbonate, polyether imide, and expanded polystyrene. They can be manufactured by any appropriate technique (injection, molding, extrusion, machining, ...).

[00042] The reinforcement elements 5 of figures 10 and 11 have a full section. Its side faces 6 each have two flat straps. As for the reinforcement element of figure 3, the gas can pass between the upper face 7 and the top of the corrugation. The reinforcement elements 5 of figures 10 and 11 can, for example, be made in counterplate, by machining.

[00043] The reinforcement element 5 of figure 11 has a tongue 22 attached to its lower face 23. Language 23 allows to fix the reinforcement element 5 on the counterplate 4, for example, at the level of the junction between two counter plates.

[00044] Figure 12 shows, on the left, the geometry of the corrugations at the level of an intersection between a large corrugation 2 and a small corrugation 3. It can be seen that the membrane present at that level is a counter-spoil 20. The right part of Figure 12 shows that the reinforcement element 5 disposed under a large corrugation 2 has, at the level of its end, claws 21 that allow the reinforcement element 5 to be fixed on the membrane by clipping at the level of the counter-spoil 20. As a variant, the claws 21 could be blockadePetition 870190091678, of 9/13/2019, p. 10/21

9/10.

[00045] Figure 13 represents, in perspective, a reinforcement element 5 that is intended to be arranged simultaneously under several large corrugations 2 and small corrugations 3. Its shape corresponds to those of the corrugations, understood there at the level of intersections. Internal passages 9 are foreseen both in the parts located under the small corrugations 3 and under the large corrugations 2.

[00046] Figure 14 represents two reinforcement elements 5, one being intended to be placed under a large corrugation 2 and the other under a small corrugation 3, crossing at the level of the crossing of the corrugations. At this level, the reinforcing elements 5 each have a notch 24 allowing them to be positioned in relation to each other. As seen in this figure, the reinforcement elements 5 have a rectangular section.

[00047] The different forms of reinforcement element 5 proposed above allow the corrugations to deform, in case of thermal contraction, and offer support to the corrugations in case of deformation due to hydrostatic and dynamic pressures. To achieve this purpose, it can be predicted that when the tank is empty (therefore, in the absence of thermal loading and hydrostatic or dynamic pressure), the minimum distance between the reinforcement element 5 and the corrugation under which it is found to be included between 0 and 5% of the height of the corrugation.

[00048] The different forms of reinforcement element 5 each have particular properties: cost and ease of manufacture, mechanical strength, quantity of form, ... Depending on the applications, the most appropriate form can be chosen.

[00049] Numerical simulations were carried out to verify the effect of reinforcement element 5 on the efforts generated in memPetition 870190091678, of 9/13/2019, p. 11/21

10/10 white without reinforcement element. These simulations showed that:

- in case of thermal loading (shrinkage of the membrane due to cold), the presence of a reinforcement element 5 does not introduce undesirable stresses on the membrane;

- in case of thermal loading and loading at uniform pressure (corresponding to the hydrostatic pressure of the loading), the presence of a reinforcing element 5 allows to reduce the efforts on the membrane; and

- in case of thermal loading and loading in asymmetric pressure (corresponding to the dynamic loading pressure), the presence of a reinforcement element 5 allows to reduce the efforts on the membrane.

[00050] Although the invention has been described in relation to a particular embodiment, it is evident that it is by no means limited and that it comprises all the technical equivalents of the described means, as well as their combinations, if they enter the scope of the invention.

Claims (16)

1. Watertight tub, of which at least one wall comprises a watertight membrane intended to be in contact with the product contained in the tub and a support adjacent to the membrane, in which the membrane comprises at least one plate (1) with at least one corrugation (2, 3), characterized by the fact that it comprises a reinforcement element (5), inserted under the corrugation, between the membrane and the support. 2. Cuba, according to claim 1, characterized by the fact that the reinforcement element has an internal passage (9) that allows the gas to circulate between the corrugation and the support, which passes through the reinforcement element. 3. Cuba, according to any of the preceding claims, characterized by the fact that an external passage allows the gas to circulate between the corrugation and the support bypassing the reinforcement element. 4. Cuba, according to any one of the preceding claims, characterized by the fact that the reinforcement element is made of a material chosen from: the backplate, polyethylene, polycarbonate, glass fiber reinforced polycarbonate, imide polyether , and expanded polystyrene. 5. Cuba, according to any one of the preceding claims, characterized by the fact that the reinforcement element comprises an external envelope, the shape of which corresponds substantially to the shape of the corrugation. 6. Cuba, according to claim 5, characterized by the fact that the reinforcement element comprises at least one reinforcement fabric (10) inside that wrap. 7. Cuba, according to any of the preceding claims, characterized by the fact that in the absence of product Petition 870190091678, of 9/13/2019, p. 13/21 2/3 contained in the vat, the minimum distance between the reinforcement element and the corrugation is between 0% and 5% of the height of the corrugation. 8. Cuba, according to any of the preceding claims, characterized by the fact that the plate is a rectangular plate and has a first series of corrugations (2) parallel to each other that run the entire length of the rectangular plate and a second series of corrugations (3) parallel to each other and transverse to the corrugations of the first series across a width of the rectangular plate, the reinforcement element (5) being inserted under a corrugation (2) of the first series. 9. Cuba, according to claim 8, characterized by the fact that the reinforcement element has a length corresponding to the distance between two corrugations of the second series. 10. Cuba, according to any of the preceding claims, characterized by the fact that the reinforcement element is inserted under the corrugation in a sliding manner in relation to the membrane and the support. 11. Cuba according to any one of claims 1 to 9, characterized by the fact that the reinforcement element is fixed on the membrane or on the support. 12. Cuba, according to claim 11, characterized by the fact that the membrane has a counter spoil (20), the reinforcement element being clipped on or blocked in the counter spoil. 13. Cuba, according to any of the preceding claims, characterized by the fact that at least two reinforcement elements are arranged respectively under two adjacent corrugations of the membrane, one of these two reinforcement elements forming a stop for the other of these two reinforcement elements reinforcement. Petition 870190091678, of 9/13/2019, p. 14/21 3/3 14. Cuba, according to any of the preceding claims, characterized by the fact that the reinforcement element has at least one weak point capable of deforming or breaking if subjected to an effort above a certain limit. 15. Cuba, according to any of the preceding claims, characterized by the fact that the plate comprises flat parts arranged between the corrugations, in which the flat parts of the plate are in contact with the support. 16. Floating construction, characterized by the fact that it comprises a vat, as defined in any of the preceding claims.