WO2021058917A1

WO2021058917A1 - Method for repairing a wall of a tank for transporting and/or storing liquefied natural gas

Info

Publication number: WO2021058917A1
Application number: PCT/FR2020/051670
Authority: WO
Inventors: Gaël TOS; Jean-Louis LEVEILLARD; Patrick Martin; Alexandre LEPRONT; Bruno Deletre
Original assignee: Gaztransport Et Technigaz
Priority date: 2019-09-26
Filing date: 2020-09-25
Publication date: 2021-04-01
Also published as: KR20220065047A; FR3101337A1; FR3101337B1; CN114502875B; CN114502875A; JP2022550346A; EP4034800A1

Abstract

The invention relates to a method for repairing a wall (4) of a tank for transporting and/or storing liquefied natural gas, the tank wall (4) comprising at least one membrane (6) and a plurality of reinforcements (12), the membrane (6) comprising a plurality of undulations (7), in at least one of which at least one reinforcement (12) is disposed, the method comprising at least one step of cutting the reinforcement (12), a step of substituting portions (23) of the reinforcement with replacement portions (27), and a step of inserting a sleeve (28) into said replacement portions (27).

Description

Title: Repair process for the wall of a liquefied natural gas transport and / or storage tank

The present invention relates to the field of transport tanks with corrugated membrane, for the storage and / or transport of a fluid, and in particular sealed and thermally insulating tanks for liquefied gas.

The invention relates to the field of sealed and thermally insulating tanks for the storage and / or transport of liquid at low temperature, such as tanks for the transport of Liquefied Petroleum Gas (LPG), for example having a temperature between -50 ° C and 0 ° C, or for the transport of Liquefied Natural Gas (LNG), at approximately -162 ° C at atmospheric pressure. These tanks can be installed on land or on a floating structure. In the case of a floating structure, the tank may be intended for the transport of liquefied gas or to receive liquefied gas serving as fuel for the propulsion of the floating structure. The sealed and thermally insulating tanks used for the storage of these liquids at low temperature are usually composed of an insulating block and a membrane composed of a plurality of waves coming into contact with the liquid cargo. Between the insulating mass and the membrane, reinforcements compatible with the shape of the waves of said membrane can be imbricated in the waves of the membrane. The reinforcements then have the function of mechanically supporting the waves of the membrane, in the presence of mechanical stress applied to the tank. The reinforcements are for example assembled by connecting pieces in order to form an integral whole.

A drawback of such a tank wall lies in its repair and more particularly the repair of a reinforcement which may or may not be inserted into one of the waves of the membrane. Indeed, the elements of the tank wall being superimposed and nested on each other, access to each of the elements of said tank wall usually requires dismantling at least part of the tank wall. The object of the invention is therefore to overcome this drawback by proposing an optimized repair method, which does not require excessive dismantling of the vessel wall.

The subject of the invention is therefore a method for repairing a wall of a liquefied natural gas transport and / or storage tank, the tank wall comprising at least one membrane and a plurality of reinforcements, the membrane comprises a plurality of 'waves in at least one of which is disposed at least one reinforcement, the reinforcement extends in a main direction of elongation and comprises at least one outer wall which delimits a cavity of the reinforcement, repair process during which, at least one step, the reinforcement is cut in a direction secant to its main direction of elongation so as to form at least a first reinforcement portion and a second reinforcement portion which can be separated from the tank wall, in another step, it is substituted the first reinforcing portion and the second reinforcing portion by at least two replacement portions and in another step, a sleeve is inserted into the cavity of the at least two replacement portions.

The tank can in particular be the tank of a liquefied natural gas transport vessel and said vessel can then include several tanks for its storage and / or transport.

The vessel wall then comprises at least one insulating block which provides the thermal insulation of the vessel necessary for the transport of liquid natural gas and may in particular comprise at least one insulation layer. The membrane comprises the plurality of waves distributed over its surface. Such a configuration of the membrane gives it greater resistance to the stresses generated on the tank, in particular the thermal shrinkage when the tank is cold, the hydrostatic pressure due to the loading of the liquid cargo, as well as the dynamic pressure due to to the movement of the cargo, in particular due to the swell. The waves on the membrane then allow it to deform to overcome these constraints.

More precisely, the plurality of waves of the membrane are arranged in first series of waves and second series of waves, perpendicular to each other and the crossing of which forms nodes. The plurality of reinforcements of the tank wall is then arranged in first series of reinforcements and second series of reinforcements, which extend perpendiculairemenr one of the aurre and respectively in the first series of waves and second series of waves. Cross-shaped connecting pieces are then arranged between each of the reinforcements of the first series of reinforcements and second series of reinforcements, and more precisely under the nodes of the membrane. It will then be understood that the cross-connecting pieces arranged under the nodes have the function of connecting the reinforcements of the first series of reinforcements and second series of reinforcements to each other and thus extend into the lower part of the cavities of each of the reinforcements.

The invention aims to cut a reinforcement of the tank wall, for example damaged, in order to form at least two reinforcement portions distributed between the first reinforcement portion and the second reinforcement portion. The reinforcing portions are then separable, in that they are adorned with the vessel wall. The sleeve threaded into the cavity of the replacement portions allows said replacement portions to be aligned along the main direction of elongation of the reinforcement. The sleeve is positioned more parriculièremenr in the upper part of the cavity of the replacement portions and forms a mechanical link between the two replacement portions. It is then understood that the replacement portions used during the process have the objective of replacing a single damaged reinforcement, that is to say a unit reinforcement before it is cut.

The invention finds an advantageous application in that it makes it possible to repair at least one of the reinforcements of the vessel wall without requiring the latter to be dismantled. Alternatively, the invention finds an advantageous application in that it allows the repair of at least one of the reinforcements during the assembly of the vessel wall. The characteristics listed below relating to a single reinforcement apply mutatis mutandis to the plurality of reinforcements which make up the tank wall.

According to the method of repairing the vessel wall, the plurality of reinforcements comprises a reinforcement adjacent to the cut reinforcement, the adjacent reinforcement being aligned along the main direction of elongation, in which method the sleeve is threaded into the adjacent reinforcement. prior to the positioning of the replacement portions. The plurality of reinforcements of the tank wall is organized as a first series of reinforcements and second series of reinforcements. Thus, by adjacent reinforcement is meant that which is arranged next to the reinforcement cut out from the same first series of reinforcements or from the same second series of reinforcements. The adjacent reinforcement therefore has the same structural characteristics as the plurality of reinforcements and the sleeve is then inserted into the cavity of the adjacent reinforcement. It is also understood that the adjacent reinforcement is separate from the damaged reinforcement and that thus, said adjacent reinforcement is not intended to be replaced by the replacement portions.

According to the process for repairing the tank wall, the sleeve is blocked in the adjacent reinforcement.

More precisely, the sleeve is temporarily blocked in the adjacent reinforcement before the implementation of the subsequent steps of the repair process. This locking of the sleeve in the adjacent reinforcement is advantageous in that it keeps the elements together and thus easy repairs to the tank wall. The locking of the sleeve in the adjacent reinforcement can be implemented by a locking means of the sleeve in the form of a screw or a washer, for example made of Teflon.

According to the process for repairing the vessel wall, the sleeve is inserted into the cavity of the replacement portions after the positioning of these replacement portions on the vessel wall.

According to an alternative of the process for repairing the vessel wall, the sleeve is translated in the direction of the main elongation of the reinforcement, from the adjacent reinforcement into the cavities of the replacement portions.

According to the process for repairing the tank wall, the sleeve is blocked in the cavities of the replacement portions.

More precisely, the sleeve is permanently blocked in the cavities of the replacemenr portions. The sleeve is locked in the cavities of the replacemenr portions by the locking means which may be a screw or a washer, for example made of Teflon. Alternatively, blocking the sleeve in the cavities replacement portions fear wanders implemented by tightening the sleeve by deformation of one end of one of the replacement portions. Still alternatively, the locking of the sleeve in the cavities of one of the replacement portions can be carried out by forming a stop on one of the replacement portions by adding an external metallic material, via a welding operation.

According to the method of repairing the vessel wall, a cavity of the adjacent reinforcement is closed to prevent the sleeve from translating therein.

Otherwise, the cavity of the adjacent reinforcement is partially closed off at its end opposite the cut out reinforcement, this operation being able to be implemented prior to the definitive locking of the sleeve in the cavities of the replacemenr portions. To this end, a closure device which may take the form for example of an adhesive can be wandered so that it at least partially closes the cavity of the reinforcement according to the conditions mentioned above.

According to the process for repairing the tank wall, prior to the step of cutting the reinforcement, a portion of membrane positioned facing the reinforcement is removed.

Otherwise, the reinforcement which is the object of the implementation of the process for repairing the vessel wall is bare sea, this step being necessary for the implementation of the subsequent steps of the process. The removal of the portion of the membrane afraid is carried out for example by a mechanical or laser cutting of said membrane.

According to the process for repairing the tank wall, a repair role of the membrane facing the reinforcement is secured.

Otherwise, the final step of the process for repairing the tank wall consists of the installation of the repair role of the membrane facing the at least one reinforcement which has been the subject of the implementation of the process. repair. It is then understood that the securing of the repair role of the membrane takes place after the placement of the replacement portions on the tank wall. To say otherwise, the role of repair is placed in substitution for the portion of the membrane which has been previously removed during the repair process. The invention also relates to a repair kit for a tank wall for transporting and / or storing liquefied natural gas, comprising at least two replacement portions intended to replace at least one reinforcement of the tank wall and at least a sleeve intended to mechanically connect the two replacement portions. The repair kit may also include a repair plate for covering the replacement portions.

The repair kit participates in the implementation of the repair process for the tank wall. It is thus understood that the two replacement portions of the repair kit are intended to both replace all or part of one and the same damaged reinforcement of the tank wall. In other words, the replacement kit according to the invention is used for the replacement of a single reinforcement of the tank wall.

According to one aspect of this kit, the sleeve is configured to fit into an upper part of a cavity of the replacement portions, the upper part of the cavity being triangular in shape.

According to another aspect, the sleeve is of circular section.

According to one characteristic of the invention, the repair kit comprises at least one means for locking the sleeve with respect to the replacement portions.

According to a feature of the invention, the repair kit comprises at least one closure device configured to close the cavity of a reinforcement adjacent to one of the replacement portions.

More specifically, the adjacent backing is aligned with the main elongation direction of the backing being the subject of the repair process, that is, the cut backing. The cut reinforcement then includes the replacement portion.

The invention also relates to a tank for transporting and / or storing liquefied natural gas for a ship, comprising a tank wall and at least one repair kit according to any one of the preceding characteristics, in which the replacement portions are made integral with the tank wall by the sleeve, the replacement portions being covered by at least one repair plate. Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows, on the one hand, and of several embodiments given by way of indication and not by way of limitation with reference to the appended schematic drawings on the other hand. share, on which:

[Fig.1] is a side perspective view of a liquid gas transport vessel with four tanks comprising the invention;

[Fig.2] is a close-up view of a tank wall showing an insulating block, a plurality of reinforcements as well as part of the membrane;

[Fig.3] is a close-up view of one of the reinforcements of the tank wall cut into a first reinforcing portion, a second reinforcing portion and a third reinforcing portion;

[Fig.4] is a close-up view of the reinforcement of Figure 3 comprising three replacement portions;

[Fig.5] is a perspective view of a sleeve according to the invention;

[Fig.6] is a close-up view of the reinforcement of Figure 4 in which the sleeve of Figure 5 is inserted;

[Fig.7] is a close-up view of a repair sheet disposed on the reinforcement of Figure 6;

[Fig.8] is a close-up view of the reinforcement of FIG. 3 where the first reinforcing portion, the second reinforcing portion and the third reinforcing portion have been removed and where an adjacent reinforcement is visible in which the sleeve is threaded. FIG. 5 according to a second embodiment of the invention;

[Fig.9] is a close-up view of the adjacent reinforcement of Figure 8 in which has been inserted the sleeve of Figure 5 and on which is visible a locking means.

[Fig.10] is a close-up view of the reinforcement of FIG. 8 in which the replacement portions have been integrated, and within which the sleeve has been translated previously inserted into the adjacent reinforcement of FIG. 7. The features, variants and different embodiments of the invention may be associated with each other, in various combinations, as long as they are not incompatible or exclusive to each other. It is in particular possible to imagine variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage or to differentiate the invention from the invention. in the state of the prior art.

In the remainder of the description, the longitudinal or transverse names refer to the orientation of the membrane according to the invention. A longitudinal direction L corresponds to the axis of the membrane in which it predominantly extends, while the transverse orientations correspond to concurrent straight lines, that is to say which intersect the longitudinal direction, in particular perpendicular to the longitudinal direction L of the membrane, as regards the transverse direction T. One of the directions, illustrated by the arrow referenced V, corresponds to a thickness of the membrane.

The directions mentioned above are visible in an orthonormal LVT frame shown in the figures.

In FIG. 1 is shown a ship 1, for example an LNG carrier, which comprises four tanks 2 for the storage of gas in the liquid state, in particular liquid natural gas. The tanks 2 are separated from each other by double transverse partitions 3, otherwise called "cofferdam". Each of the tanks 2 is formed by a tank wall 4 comprising, among other things, an insulating block 5, visible in FIG. 2, partly forming the thermal insulation of the tank wall 4, and at least one membrane 6 intended for wanders in contact with the liquid cargo and anchored to the insulating block 5.

The membrane 6, visible in FIG. 2, is a plate made of an anti-corrosion material, in particular stainless steel, with a thickness, for example between 0.5 mm and 1.5 mm, advantageously 1.2 mm, measured in the vertical direction V membrane 6. The membrane can also include a length of 680 mm and 3060 mm, measured in the longitudinal direction L of the membrane 6. Finally, the membrane 6 can include a width between 680 mm and 1030 mm, measured in the transverse direction T of the membrane 6.

The membrane 6 comprises a plurality of waves 7 distributed in a plurality of first series of waves 8 parallel to each other and extending in the longitudinal direction L of the membrane and a plurality of second series of waves 9 parallel to each other and extending in the transverse direction T of the membrane 6.

The first wave series 8 and the second wave series 9 extend mainly along directions which are perpendicular to each other, and form nodes 10 at their intersection. The nodes 10 emerge vertically from a plane AB in which The membrane 6. The wave 7 is understood to mean a deformation of the surface of the membrane 6 in the vertical direction V.

The membrane 6 also comprises flat portions 11 in the shape of a quadrilateral, of which the two cores which extend in the longitudinal direction L of the membrane 6 are delimited by two first series of waves 8, and the two cores which extend in the transverse direction T of the membrane 6 are delimited by two second series of waves 9. The set of flat portions 11 then define the undeformed surface of the membrane 6 extending along the plane AB of the membrane 6 and coming into contact with the insulating block 5 of the tank wall 4, when the membrane is mounted against the insulating block 5.

FIG. 2 also shows the presence of reinforcements 12, distributed among first reinforcements 13 and second reinforcements 14. In the remainder of the derailed description, the first reinforcements 13 and the second reinforcements 14 will be grouped together under the term reinforcement 12, when the characteristics mentioned apply both to the first reinforcements 13 and to the second reinforcements 14. The invention is nevertheless not limited to a plurality of reinforcements 12 and applies as soon as it is necessary to implement the repair process on at least one reinforcement 12 of the tank wall 4.

The first reinforcements 13 are aligned to form at least a first series of reinforcements 15 extending in the longitudinal direction L of the membrane 6. The second reinforcements 14 are aligned to form at least a second series of reinforcements 16 extending in the transverse direction T of the membrane 6. The first series of reinforcements 15 and the second series of reinforcements 16 therefore intersect, in particular perpendiculairemenr. The first reinforcements 13 are arranged in the first series of waves 8 of the membrane 6. It is understood that the first reinforcements 13 are positioned so as to wander nested in the deformation of the wave 7, the shape of the first reinforcements 13 being complementary. the shape of the waves of the first wave series 8 of the membrane 6.

The second reinforcements 14 are arranged in the second series of waves 9 of the membrane 6. It is then understood that the second reinforcements 14 are positioned so as to wander nested in the deformation of the wave 7, the shape of the second reinforcements 14 being complementary to the shape of the waves 7 of the second series of waves 9 of the membrane 6.

It is also understood that the intersection between the first series of reinforcements 15 and the second series of reinforcements 16 is positioned under a node 10 of the membrane 6.

The reinforcements 12 comprise an outer wall 17 which delimits a cavity 18. It is then understood from the above that the outer wall 17 provides a shape to the reinforcements 12 so that they are after wandering arranged in the waves 7 of the membrane 6 according to the previous characteristics. Connecting pieces 21, are arranged in the first reinforcements 13 and in the second reinforcements 14 of the membrane 6, so that they are connected together under the series of waves 8, 9 of the membrane 6. The parts connection 21 are thus placed in line with a node 10 of the membrane 6 and inserted into each of the cavities 18 of the reinforcements 12. The connection pieces 21 can wander, for example and without limitation, in the form of a cross 22. It will then be understood that the set of reinforcements 12 making up the first series of reinforcements 15 and the second series of reinforcements 16 form an integral assembly arranged between the membrane 6 and the insulating block 5 of the tank wall 4 as has been described. previously. A method of repairing the vessel wall 4 will now be described in connection with FIGS. 3 to 10. More specifically, the repair method allows the implementation of a simplified repair of the vessel wall 4, for example the repair. repair of at least one of the reinforcements 12 of said tank wall 4. In the remainder of the description, it will be understood that the method can be implemented on at least one of the reinforcements 12 of the first series of reinforcements 15 and / or on at least one of the reinforcements 12 of the second series of reinforcements 16. Thus one defines and groups together under the term of the main direction of elongation of the reinforcement, the longitudinal direction L of the membrane 6 for the first reinforcements 13 and the transverse direction T membrane 6 for the second reinforcements

14.

A first step in the repair process for the tank 2 consists in providing access to the reinforcement 12 making the repair process object to the operator. To this end, a portion P, visible in FIG. 2, of the membrane 6 located opposite the reinforcement 12 is removed, for example by means of laser or mechanical cutting.

It should be considered that alternatively and not illustrated, the repair process can be implemented during the assembly of the tank wall, before the membrane is arranged to cover the reinforcements that make up the tank wall, and that 'thus the first step of removing the membrane portion is not implemented.

Once the reinforcement 12 has been exposed, a second step of the repair process consists in cutting the reinforcement 12 in a direction secant to its main direction of elongation, so as to form portions of reinforcement 23, and more precisely at least a first reinforcing portion 24 and a second reinforcing portion 25. In the example illustrated, a third reinforcing portion 26 is also formed, but it is understood that the method can be applied to more or less reinforcing portions 23.

It is also understood that during the second step of the process, a single and same reinforcement 12 is cut out of the tank wall 4, so that this same reinforcement 12 becomes the first reinforcement portion 24, the second reinforcement portion 25 and the third reinforcement portion 26 after cutting the reinforcement 12. Thus, according to the example illustrated in FIG. 3, the first reinforcing portion 24, the second reinforcing portion 25 and the third reinforcing portion 26 are obtained, which are intended to be separated from the vessel wall 4. The term " separable from the vessel wall 4 that the reinforcing portions 24, 25, 26 are intended to be permanently removed from the vessel wall 4 in order to be replaced by replacement portions 27.

Alternatively and not illustrated, at least one of the reinforcing portions 24, 25, 26 may be removable, in that it may be reinstalled on the vessel wall following the substitution of at least one of the portions. reinforcements 24, 25, 26 by at least one replacement portion 27.

According to a first embodiment of the method visible in FIG. 4, after the removal of the first reinforcing portion 24, of the second reinforcing portion 25 and of the third reinforcing portion 26, the replacement portions are placed. 27, such that they replace said first reinforcing portion 24, second reinforcing portion 25 and third reinforcing portion 26. It is then understood that the replacement portions 27 are all three aligned in the direction of elongation of the reinforcement 12. It is also understood that the replacement portions 27 have the function of replacing one and the same reinforcement 12 of the tank wall 4.

Subsequently, in an additional step, a sleeve 28 is threaded, visible in FIG. 5, at least in two cavities 18 of two replacement portions 27. In the example illustrated in FIG. 6, the sleeve 28 is threaded into the three cavities 18 of the three replacement portions 27.

The sleeve 28 has an elongated shape as well as a first end 29 and a second end 30, opposite each other on either side of the sleeve 28. The insertion of the sleeve 28 as previously mentioned, s 'mainly carried out by a translatory movement, following the main direction of elongation of the reinforcement 12, from the second end 30 to the first end 29, which is then referred to as the first direction of insertion II. The function of the sleeve 28 is then to block at least the movements between the replacement portions 27 in directions perpendicular to the direction of elongation of said reinforcement 12. Still in this first embodiment, provision can be made for inserting the sleeve 28 according to the preceding insertion characteristics, in turn leaving the second end 30 of the sleeve 28 outside a volume defined by the cavity 18 of the sleeve. one of the replacement portions 27 located at one end of the alignment of the replacement portions 27. In this way, a locking means 31 is allowed for the sleeve 28 at its second end 30. The means of blocking 31 fear wanders for example and without limitation a screw or a Teflon washer. The blocking means 31 has the function of blocking the movement of the sleeve 28, here definitively, following the translatory movement described above, at least in the first direction of insertion 11 by forming a stop against the replacement portion 27. De alternatively, the locking means 31 fear a deformation of one of the replacement portions 27 so that it prevents the movements of the sleeve 28, or an addition of a metallic material on one of the replacement portions 27 in order to to form a stop means and to connect so that the sleeve 28 is left free.

Subsequently, there is a repair role 32 of membrane 6, visible in FIG. 7, covering the replacement portions 27. It is then understood that the repair role 32 has dimensions in the longitudinal direction L and transverse T of the membrane 6 substantially identical to the dimensions in these same directions, of the portion P removed during the first step.

The repair role 32 can then be welded to the rest of the membrane 6 in order to restore the leakage thereof.

According to a second embodiment of the invention, after removing the first reinforcing portion 24, the second reinforcing portion 25 and the third reinforcing portion 26 from the vessel wall, in an additional step , the sleeve 28 is threaded into the cavity 18 of a reinforcement 33 adjacent to the cutout reinforcement 12, that is to say that which is the object of the repair process. By adjacent reinforcement 33 is meant the reinforcement arranged alongside the reinforcement 12 cut out and aligned along the direction of elongation of the reinforcement 12. The adjacent reinforcement 33 is also distinguished in that it is not intended to be replaced. by the replacement portions 27, the latter being used exclusively for the sole reinforcement 12 object of the repair. In other words, the cut out reinforcement 12 and the adjacent reinforcement 33 are separate but form part of the same first series of reinforcements 15 or second series of reinforcements 16, and are directly connected to each other by one of the connecting pieces. 21 of said series of reinforcements 15, 16.

The sleeve 28 is then inserted into the cavity 18 of the adjacent reinforcement 33 by a translational movement along the main direction of elongation of the reinforcement 12, in a second direction of insertion 12 going from the first end 29 towards the second end 30, to connect so that the first end 29 emerges outside a volume defined by the cavity 18 of the adjacent reinforcement 33, opposite the first reinforcement portion 24.

According to an example of the invention, visible in FIG. 9, it is possible to have the locking means 31 of the sleeve 28 at its first end 29. In this configuration, the locking means 31 temporarily prevents the movement of the sleeve 28. following the translatory movement previously described in the second direction of insertion 12. The locking means 31 can then be here, the screw or the Teflon washer.

Another step of the method according to this second embodiment, consists as for the first embodiment, in replacing the first reinforcing portion 24, the second reinforcing portion 25 and the third reinforcing portion 26 by the replacement portions 27, and connects so that the three replacement portions 27 are aligned in the main direction of elongation of the reinforcement 12 as can be seen in FIG. 10.

As illustrated in Figure 10, following this step, we rerire the locking means 31 of the sleeve 28 positioned at its first end 29 and said sleeve 28 is translated in the main direction of elongation of the reinforcement 12, according to the first direction of insertion II connects so that it fits at least into the cavities 18 of two replacement portions 27. According to an example of the invention, the second end 30 can remain outside the cavity 18 of a replacement portions 27 located in look at the adjacent reinforcement 33, so that the locking means 31 of the sleeve 28 are placed on said second end 30 of the sleeve 28. Thus, the translatory movement of the sleeve 28 is definitively blocked in the first direction of insertion II and according to the second direction of insertion 12, the locking means 31 forming a stop against the replacement portion 27 and the adjacent reinforcement 33.

An additional step of this second embodiment of the method, perhaps the closing of the cavity 18 of the adjacent reinforcement 33 at the level of its end facing the cut-out reinforcement 12, by means of a closure device 34. In other words, the end of the cavity 18 of the adjacent reinforcement 33 located opposite the second end 30 of the sleeve 28 carrying the locking means 31 is closed off. In this way, the locking means 31 are allowed to be removed from the second end 30 of the sleeve 28, the closure device 34 preventing the sleeve 28 from translating into the cavity 18 of the adjacent reinforcement 33 along the second direction of insertion 12.

According to one example, the closure means 34 may take the form of an adhesive strip. According to another example of the invention, the closure means 34 can comprise at least one synthetic insert having a shape complementary to the cavity 18 of the adjacent reinforcement 33. The closure means 34 can then be placed inside the cavity. 18 of the adjacent reinforcement 33 or outside the latter.

Also, this closure means 34 can be assembled by force around the adjacent reinforcement 33 or in the cavity 18 of said adjacent reinforcement 33, the closure means 34 then being able to be crenellated to ensure a mechanical strength of said closure means 34 on or in the adjacent reinforcement 33.

Alternatively, the closure device 34 can be put in place prior to the definitive locking of the sleeve 28 in the cavities 18 of the replacement portions 27 by the locking means 31.

Finally and in a manner common to the first embodiment of the invention, the repair plate 32 of the membrane 6, visible in FIG. 7, is placed in the covering of the replacement portions 27. The repair role 32 then has structural characteristics. identical as in the first embodiment of the invenrion. The present invention should not however be limited to the means and configurations described and illustrated here, and it also extends to any equivalent means and configuration and to any technically operative combination of such means.

Claims

1. A method of repairing a tank wall (4) for transporting and / or storing liquefied natural gas, the tank wall (4) comprising at least one membrane (6) and a plurality of reinforcements (12), the membrane (6) comprises a plurality of waves (7) in at least one of which is disposed at least one reinforcement (12), the reinforcement (12) extends in a main direction of elongation and comprises at least one wall external (17) which delimits a cavity (18) of the reinforcement (12), repair process during which, in at least one step, the reinforcement (12) is cut in a direction secant to its main direction of elongation of connects so as to form at least a first reinforcing portion (24) and a second reinforcing portion (25) separable from the tank wall (4), in another step, the first reinforcing portion (24) and the second are replaced reinforcement portion (25) by at least two replacement portions (27) and at another stage, a sleeve (28) is inserted into the cavity (18) at least two replacement portions (27). 2. The method of repair according to claim 1, wherein the plurality of reinforcements (12) comprises a reinforcement (33) adjacent to the reinforcement (12) cut away, the adjacent reinforcement (33) being aligned along the main direction of elongation. , Process during which the sleeve (28) is threaded into the adjacent reinforcement (33) prior to the posirionnemenr of the replacement portion (27). 3. Repair method according to claim 2, during which the sleeve (28) is blocked in the adjacent reinforcement (33).

4. Repair method according to claim 1 or 3, during which the sleeve (28) is inserted into the cavity (18) of the replacement portions (27) after the posirionnemenr of these replacement portions (27) on the wall of tank (4). 5. Repair method according to the preceding claim, during which the sleeve (28) is translated in the direction of the main elongation of the reinforcement (12), from the adjacent reinforcement (33) into the cavities (18) of the portions of replacement

(27).

6. Repair method according to the preceding claim, during which the sleeve (28) is blocked in the cavities (18) of the replacement portions (27).

7. Repair method according to claim 2 and 6, during which a cavity (18) of the adjacent reinforcement (33) is closed to prevent the sleeve (28) from translating therein.

8. Repair method according to any one of the preceding claims, during which, prior to the step of cutting the reinforcement (12), a portion (P) of membrane (6) positioned opposite the reinforcement (12) is removed. .

9. A repair method according to claim 7, during which a repair role (32) of the membrane (6) facing the reinforcement (12) is secured.

10. Repair kir of a tank wall (4) for transporting and / or storing liquefied natural gas, comprising at least two replacement portions (27) intended to replace at least one reinforcement (12) of the wall of tank (4), at least one sleeve (28) intended to mechanically connect the two replacement portions (27) and at least one closure device (34) configured to close a cavity (18) of an adjacent reinforcement (33) to one of the replacement portions (27).

11. Repair Kir according to claim 10, comprising at least one locking means (31) of the sleeve (28) relative to the replacement portions (27).

12. Liquefied natural gas transport and / or storage tank for a ship, comprising a tank wall (4) and at least one repair kir according to any one of claims 10 or 11, wherein the replacement portions (27) are made integral with the tank wall (4) by the sleeve (28), the replacement portions (27) being covered by at least one repair role (32).