WO2020193584A1

WO2020193584A1 - Method for manufacturing mastic beads

Info

Publication number: WO2020193584A1
Application number: PCT/EP2020/058234
Authority: WO
Inventors: Pierre LANDRU
Original assignee: Gaztransport Et Technigaz
Priority date: 2019-03-25
Filing date: 2020-03-24
Publication date: 2020-10-01
Also published as: FR3094477A1; CN113710950B; FR3094477B1; KR20210154144A; CN113710950A

Abstract

The invention relates to a method for manufacturing mastic beads intended for installing a sealed, thermally insulating vessel in a supporting structure, which comprises the steps of: - determining a plurality of deviations (27) between a plurality of measurement points distributed on an external surface of the vessel and the internal surface of the supporting structure, said deviations (27) being determined parallel to a thickness direction of the vessel at said measurement points, said deviations (27) being determined as a function of an implantation position of the vessel in the internal space of the supporting structure and of three-dimensional dimensions of said vessel and of said internal space of the supporting structure, - manufacturing mastic beads intended for being applied between the internal surface of the supporting structure and the external surface of the vessel, said beads having cross-sectional dimensions defined as a function of said determined deviations (27).

Description

Mastic bead manufacturing process

The invention relates to the field of sealed and thermally insulating tanks with membranes. In particular, the invention relates to the field of sealed and thermally insulating tanks for the storage and / or transport of liquefied gas at low temperature, such as tanks for the transport of Liquefied Petroleum Gas (also called LPG) exhibiting by example 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.

In one embodiment, the liquefied gas is LNG, which is a mixture with a high methane content stored at a temperature of about -162 ° C at atmospheric pressure. Other liquefied gases can also be considered, including ethane, propane, butane or ethylene, but also hydrogen. Liquefied gases can also be stored under pressure, for example at a relative pressure between 2 and 20 bar, and in particular at a relative pressure close to 2 bar. The tank can be produced using different techniques, in particular in the form of an integrated membrane tank or a self-supporting tank.

Technological background

A sealed and thermally insulating tank for liquefied natural gas storage arranged in a supporting structure has a multilayer structure, namely from the outside to the inside of the tank, a secondary thermally insulating barrier anchored against the supporting structure, a waterproof membrane secondary which rests on the secondary thermally insulating barrier, a primary thermally insulating barrier which rests on the secondary waterproof membrane and a primary waterproof membrane which rests on the primary thermally insulating barrier and which is intended to be in contact with the liquefied natural gas stored in tank.

According to an exemplary embodiment of such a tank, each thermally insulating barrier, primary and secondary, comprises a set of insulating blocks, respectively primary and secondary (according to other embodiments, the tank has only one barrier thermally insulating), of generally parallelepipedal shape which are juxtaposed and which thus form a support surface for the respective waterproof membrane. This support surface must have good flatness in order to provide a continuous and flat support for the waterproof membranes. In fact, the walls of tanks are subject to numerous thermal, hydrostatic and hydrodynamic constraints when the tank contains LNG. A flat and continuous bearing surface avoids the generation of stress concentration areas in the waterproof membrane, these stress concentration areas potentially causing degradation of the waterproof membrane.

However, although the insulating blocks have a flat internal surface to form the support surface of the waterproof membrane, the supporting structure on which said blocks are anchored does not always have sufficient flatness for the blocks anchored on said supporting structure to form a continuous and flat support surface. For example in the context of a supporting structure formed by the double hull of a ship, the junction zones between the various portions of the double hull form irregularities with respect to the general plane of the corresponding supporting wall, these irregularities being by example related to the weld between said two portions of double shell.

In order to make up for these flatness defects, beads of mastic are usually interposed between the insulating blocks and the supporting structure, as described in FR-A-2259008. In particular, the beads of mastic can be deposited on a lower surface of the insulating blocks in a plastic state, then pressed against the bearing wall to flow until exactly filling the gap between the bearing wall and the insulating blocks when the latter are in their final position. Such cords of mastics are for example also described in documents FR2909356, FR2877638 or WO14057221 which describe different structures of sealed and thermally insulating tanks integrated in different types of load-bearing structures.

summary

An idea underlying the invention is to provide a method of manufacturing cords of mastics intended to be interposed between a sealed and thermally insulating tank and a supporting structure. In particular, an idea underlying the invention is to manufacture cords of sealants having a satisfactory thickness dimension to allow the formation of a support surface for the waterproof membranes having a satisfactory flatness. An idea underlying the invention is also to avoid excessive consumption of putty during the manufacture of the mastic beads.

According to one embodiment, the invention provides a method of manufacturing cords of mastics intended to install a sealed and thermally insulating tank in a supporting structure, the supporting structure comprising an internal surface delimiting an internal space,
the process comprising the steps of:
- determining a plurality of differences between a plurality of measurement points distributed on an external surface of the tank and the internal surface of the supporting structure, said differences being determined parallel to a thickness direction of the tank at the level of said points of measurement, said deviations being determined as a function of an implantation position of the tank in the internal space of the supporting structure and of three-dimensional dimensions of said tank and of said internal space of the supporting structure,
- Manufacturing mastic beads intended to be applied between the internal surface of the supporting structure and the external surface of the tank, said beads having cross-sectional dimensions defined as a function of said determined deviations.

Thanks to these characteristics, it is possible to manufacture cords of mastics making it possible to compensate for the defects of flatness of the internal surface of the supporting structure. In addition, cords of mastics produced by such a process make it possible to provide a thermally insulating barrier having satisfactory flatness for the support of the waterproof membrane.

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

A bead of mastic can be made by depositing an amount of polymerizable mastic in a plastic state on a surface selected from the internal surface of the supporting structure and the external surface of the vessel. The cross-sectional shape of the bead of mastic thus deposited may be more or less irregular, for example approximately circular. This shape is then modified into a substantially rectangular section by crushing between the internal surface of the supporting structure and the external surface of the tank during the installation of the tank in the supporting structure, then the bead hardens by polymerization in this shape. substantially rectangular. The cross section of the bead during the deposition of the polymerizable mastic is preferably sufficient so that the section of the bead of finally cured mastic has a width greater than or equal to a predefined constant. This predefined constant (i.e. minimum admissible width) can be obtained in an earlier phase by a sizing calculation.

According to one embodiment, the bead of mastic is produced continuously over a length corresponding to the length of application of said bead of mastic on the external surface of the tank or the internal surface of the supporting structure.

According to one embodiment, such a method may further comprise:
- providing a plurality of sizes of cross section, said plurality of sizes comprising an integer t of sizes, the plurality of sizes having an upper limit, said upper limit being greater than a rectangular section associated with the maximum deviation of the a plurality of gaps, the associated rectangular section having a predefined width and a height equal to the maximum gap of the plurality of gaps.
In this method, the sealant beads are made with cross-sectional dimensions selected from said plurality of sizes.

According to one embodiment, the integer t is less than a total number of said deviations of the plurality of deviations.

Thanks to these characteristics, it is possible to limit the number of different sizes of sealant beads to be manufactured. Such a manufacturing process thus allows simple and rapid manufacturing of the sealant beads to make up for the flatness defects of the supporting structure. If the deviation distribution is very heterogeneous, especially if a few very high values are isolated from the remainder of the distribution, it may be advantageous to treat the few larger deviations separately, for example by building custom mastic beads for these isolated points, and determine the plurality of sizes only to cover the remaining deviation distribution.

The invention is not limited to the production of a limited number of sizes of cords optimized to compensate for the flatness defects of the supporting structure, it makes it possible to offer a flexible choice to the operators, in charge of the assembly / assembly of each tank in a supporting structure, with regard to two key parameters, namely:
- a limited number of sizes of mastic beads adapted to the flatness defects of the supporting structure, and
- perfect optimization of the quantity of mastic necessary for adequate assembly / assembly (with regard to all the structural and mechanical strength requirements) and perennial of the tank in the supporting structure.

Thus, depending on the step of determining a plurality of differences between a plurality of measurement points distributed over an external surface of the tank and the internal surface of the supporting structure, that is to say essentially in depending on the precision or the number of measurement points during such a determination step, the operators, thanks to the method according to the invention, have the possibility of favoring the choice of a limited number of sizes of mastic beads, for example a number of sizes of mastic beads desired between 3 and 8, or to favor the perfect optimization of the quantity of mastic necessary for the assembly / assembly operation of the tank.

Indeed, the management of a large number of sizes of mastic beads can be problematic for operators or simply impossible given the unsuitable manufacturing equipment of said beads.

In the latter case, the invention nevertheless not only makes it possible to optimize the size of the mastic beads with the flatness defects of the supporting structure in order to reduce the non-technically useful quantity of mastic but also offers the operators the possibility of choosing the number sizes of cords that they desire or that they can use as part of the tank assembly / assembly operation.

In a reverse situation where operators have putty bead making equipment that allows them to fabricate an unlimited number of sizes of putty beads and these operators choose or are willing to use as many sizes of putty bead as they can. 'it will be useful or necessary to reduce the amount of mastic not technically useful, the invention allows the best possible optimization of the amount of mastic.

un choix d’un nombre de tailles de cordons de mastic, prédéterminé ou déterminable dans un domaine de nombre de tailles de cordons de mastic suite à l’étape de de détermination d’une pluralité d’écarts entre une pluralité de points de mesure distribués sur une surface externe de la cuve et la surface interne de la structure porteuse,
les caractéristiques de l’équipement de fabrication de cordons de mastic (en particulier ses capacités de fabrication et sa localisation),
la nature et les caractéristiques du mastic (à l’heure actuelle de type époxy incorporant un taux élevé de charges et/ou de microsphères),
les caractéristiques des opérateurs (nombre, qualification etc.) en charge du montage/assemblage de la cuve dans la structure porteuse.

For all the intermediate situations between the two extreme situations described above, the method according to the invention provides an optimized technical solution, taking into account in particular, but not exclusively, the parameters relating to:

a choice of a number of sizes of mastic beads, predetermined or determinable in a range of number of sizes of mastic beads following the step of determining a plurality of differences between a plurality of distributed measurement points on an external surface of the tank and the internal surface of the supporting structure,
the characteristics of the mastic bead manufacturing equipment (in particular its manufacturing capabilities and location),
the nature and characteristics of the mastic (currently epoxy type incorporating a high rate of fillers and / or microspheres),
the characteristics of the operators (number, qualification, etc.) in charge of mounting / assembling the tank in the supporting structure.

According to one embodiment, for a deviation of the plurality of deviations, a bead of mastic is manufactured, the cross-sectional dimension of which is equal to a minimum size among the sizes which is greater than or equal to a rectangular section associated with said deviation, the associated rectangular section having said predefined width and a height equal to said gap.

By virtue of these characteristics, the cords of mastics produced make it possible to correct the flatness defects of the supporting structure satisfactorily without excessive consumption of mastic.

According to one embodiment, the step of providing the plurality of cross section sizes comprises:
- calculate a frequency of occurrence of the deviations of the plurality of deviations,
- calculating the plurality of sizes of sealant beads as a function of the frequency of occurrence of the deviations and the determined deviations so that each deviation of the plurality of deviations can be associated with a size of the plurality of sizes which is immediately greater than the rectangular section associated with said gap, and so as to limit an accumulated difference between the rectangular sections associated with said gaps of the plurality of gaps and said sizes with which said gaps are associated.

In addition to what has been explained previously, the fixing of the number t of different sizes and / or the calculation of the t sizes are operations which can be carried out according to different strategies. For example, the fixing of the number t of different sizes and / or the calculation of the t sizes can be carried out for a larger or smaller construction unit, for example for a plurality of tanks, for a single tank or for a portion of the tank, in particular for a flat wall of a polyhedral tank, or even for a portion of a flat wall. It is necessary to reconfigure the mastic bead production tool more often than the construction unit for which the calculation was made is small.

If the number t is very high, for example close to the total number of bead of sealants to be manufactured in the building unit, the process amounts to manufacturing each bead of sealant to measure, which very substantially eliminates any overconsumption of sealant, but Significantly increases operational constraints when installing the tank, since each bead of sealant will have to be manufactured and routed to a precisely localized location. Conversely, a relatively low number t makes it possible to standardize the manufacture of mastic beads, at least for one construction unit, and to reduce operational constraints. According to one embodiment, the whole number t of sizes is less than or equal to 10, preferably less than or equal to 5.

According to one embodiment, such a method may further comprise:
- carry out a three-dimensional measurement of the internal space of the supporting structure,
- defining dimensions and a shape of the tank as a function of said three-dimensional measurement so as to allow the insertion of said tank into the internal space of the supporting structure,
- Define the installation position of the tank in the internal space of the supporting structure as a function of the three-dimensional measurement of the internal space of the supporting structure and the dimensions and shape of the defined tank.

Thanks to these characteristics, it is possible to know the gaps to be made up precisely, thus allowing a more precise manufacture of the sealant beads.

According to one embodiment, the tank comprises a plurality of insulating blocks comprising bottom panels defining said outer surface of the tank, and in which defining an implantation position of the tank comprises defining an anchoring position for the plurality of insulating blocks on the internal surface of the supporting structure.

According to one embodiment, one or more or each of the insulating blocks has a parallelepipedal shape, for example rectangular parallelepiped.

According to one embodiment, the measurement points comprise, for each insulating block, a point of a bottom panel of said insulating block when said insulating block is in the anchoring position.

According to one embodiment, the supporting structure comprises at least one flat supporting wall, the tank comprising a tank wall comprising a plurality of insulating blocks intended to be anchored on the supporting wall, said insulating blocks having an internal surface parallel to the control panel. bottom, said internal surface forming a support surface for a sealed membrane of the vessel wall, the method further comprising:
- determine a reference plane for the load-bearing wall,
and the anchoring position of the insulating blocks is defined so that the internal surface of said insulating block has, when said insulating block is in the anchoring position, an inclination less than a threshold angle with respect to the reference plane.

According to one embodiment, a tank wall comprises a plurality of insulating blocks juxtaposed in a regular pattern.

According to one embodiment, the sealed and thermally insulating tank further comprises a sealed membrane resting on the internal surface of the insulating blocks.

According to one embodiment, the threshold angle is less than Arctan (10 ^- ²), preferably less than Arctan (6.10 ^-3 ).

According to one embodiment, the cords of sealants are manufactured so that the internal surface of the insulating block has an inclination less than said threshold angle with respect to the internal surface of an insulating block having an adjacent anchoring position on the load-bearing wall.

According to one embodiment, the sealant beads are made with a length less than or equal to a dimension of the bottom panel of an insulating block.

According to one embodiment, the internal space of the supporting structure has a longitudinal direction, a transverse direction and a height direction, the method comprising the steps of
- defining a longitudinal central axis of the tank, said longitudinal central axis being parallel to the longitudinal axis of the internal space of the supporting structure,
- defining a transverse central axis of the tank, said transverse central axis being parallel to the transverse axis of the internal space of the supporting structure, and
- Define a central height axis of the tank, said central height axis being parallel to the height axis of the internal space of the supporting structure.

According to one embodiment, the step of positioning the tank in the internal space of the supporting structure comprises a step of defining a plurality of first positioning lines and a plurality of second positioning lines, the first positioning lines being parallel to each other, the second positioning lines being parallel to each other, the first positioning lines being perpendicular to the second positioning lines, the first positioning lines being spaced by a first spacing step equal to the dimension on a first side of the outer surface of an insulating block, the second positioning lines being spaced apart by a second spacing pitch equal to the dimension of a second side of the outer surface of said insulating block.

According to one embodiment, at least one of the longitudinal central axis of the tank, the transverse central axis of the tank and the central height axis of the tank defines a first or a second positioning line of the tank. vessel wall and / or an axis of symmetry of the first or second positioning lines of said vessel wall.

According to one embodiment, the invention also provides a storage installation comprising a supporting structure and a sealed and thermally insulating tank installed in an internal space of the supporting structure, said storage installation comprising cords of sealants produced according to the aforementioned methods. and applied between an internal surface of the internal space of the supporting structure and an external surface of the vessel.

Such a tank can be part of an onshore storage installation, for example to store LNG or be installed in a floating, coastal or deep water structure, in particular an LNG vessel, a floating storage and regasification unit (FSRU). , a floating production and storage unit (FPSO) and others. Such a tank can also serve as a fuel tank in any type of vessel.

According to one embodiment, the invention also provides such a storage facility in the form of a vessel for the transport of a cold liquid product comprising a double hull forming said supporting structure.

According to one embodiment, the invention also provides a method for loading or unloading such a ship, in which a cold liquid product is conveyed through isolated pipes from or to a floating or land storage installation to or from the vessel tank.

According to one embodiment, the invention also provides a transfer system for a cold liquid product, the system comprising the aforementioned vessel, insulated pipes arranged so as to connect the tank installed in the hull of the vessel to a floating storage installation. or terrestrial and a pump for driving a flow of cold liquid product through the insulated pipes from or towards the floating or terrestrial storage installation towards or from the vessel of the vessel.

Brief description of the figures

. 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.

FIG. 1 is a cutaway view of a supporting structure intended to receive a sealed and thermally insulating tank.

FIG. 2 is a schematic representation of the transverse wall of the supporting structure of FIG. 1 illustrating the position of installation of the insulating blocks of the sealed and thermally insulating tank wall intended to be anchored to said transverse supporting wall.

FIG. 3 is a sectional view of the transverse bearing wall of FIG. 2 illustrating the defects of flatness of an internal surface of said transverse bearing wall.

Figure 4 is a sectional view of the transverse load-bearing wall of Figure 3 illustrating an optimum reference plane.

FIG. 5 is a view similar to FIG. 4 illustrating an interpolation of the reference plane of FIG. 4 by linear sections corresponding to the dimensions of the insulating blocks of the vessel wall intended to be anchored on said transverse bearing wall.

Figure 6 is a view similar to Figure 3 on which are anchored insulating blocks of the sealed and thermally insulating tank wall.

FIG. 7 is a graph illustrating the dimensions of the sealant beads as a function of the frequency of occurrence of the gaps to be made up between the external surface of the sealed and thermally insulating tank and the internal surface of the supporting structure and manufactured according to different methods of production.

FIG. 8 is a cut-away schematic representation of an LNG tanker tank comprising a sealed and thermally insulating tank and of a loading / unloading terminal for this tank.

In the remainder of the description, the terms “external” and “internal” will be used to designate, according to the definitions given in the description, the relative position of an element with respect to another, by reference inside the tank. Thus, an element close to or facing the interior of the tank is referred to as internal as opposed to an external element located close to or facing the outside of the tank.

In relation to Figure 1, there is a supporting structure 1 intended to receive the walls of a sealed and thermally insulating tank. The supporting structure 1 is formed by the double hull of a ship. The supporting structure 1 has a general polyhedral shape. The supporting structure 1 has transverse walls 2, typically front and rear, here octagonal in shape. In Figure 1, the front transverse wall 2 is only partially shown in order to allow visualization of an internal space 9 of the supporting structure 1. The transverse walls 2 are cofferdam walls of the ship and extend transversely to the longitudinal direction of the ship. The supporting structure 1 also comprises an upper wall 3, a lower wall 4 and side walls 5. The upper wall 3, the lower wall 4 and the side walls 5 extend in the longitudinal direction of the ship and connect the transverse walls 2 front and rear.

The upper wall 3 comprises, near the rear transverse wall 2, a space, of rectangular parallelepiped shape, projecting upwards, called the liquid dome 6. The liquid dome 6 defines an opening 7 of the upper wall 3 allowing passage. of liquid transfer pipes from or to the tank when the latter is mounted in the supporting structure 1.

The supporting

walls

2, 3, 4, 5 of the supporting structure have an internal surface 10 defining the internal space 9 in which the tank is housed. The tank comprises a plurality of tank walls, each tank wall being anchored to a respective supporting

wall

2, 3, 4, 5 of the supporting structure 1.

In the example chosen here to illustrate, the tank is a membrane tank having a multilayer structure. Also, each wall of the tank has successively, from the outside to the inside, according to the thickness direction of the corresponding tank wall, a secondary thermally insulating barrier anchored on the corresponding

bearing wall

2, 3, 4, 5 , a secondary waterproof membrane resting on the secondary thermally insulating barrier, a primary thermally insulating barrier resting against the secondary waterproof membrane and a primary waterproof membrane resting on the primary thermally insulating barrier and intended to be in contact with the fluid contained in the tank.

By way of example, the walls of the tank can be manufactured according to different techniques described in FR-A-2691520, FR-A-2877638, or WO-A-14057221. In these different embodiments, each tank wall comprises a plurality of insulating blocks 11 forming at least the secondary thermally insulating barrier. These insulating blocks 11 are prefabricated outside the internal space and have standardized dimensions.

According to an embodiment such as for example described in document FR2877638, the insulating blocks 11 are of parallelepiped shape. The primary and secondary thermally insulating barriers are formed by a plurality of these juxtaposed parallelepipedal insulating blocks 11.

According to another embodiment for example described in document FR2691520, the insulating blocks 11 comprise a portion of a secondary thermally insulating barrier and a portion of a primary thermally insulating barrier superimposed. A waterproof layer forming a portion of the secondary waterproof membrane being interposed between these two portions of thermally insulating barrier. In this embodiment, the portions of the primary and secondary insulating barriers have parallelepipedal shapes and the portion of the primary thermally insulating barrier has dimensions smaller than the dimensions of the portion of the secondary thermally insulating barrier.

In all these cases, the insulating blocks 11 have a bottom panel forming a rectangular outer surface 12, this outer surface 12 being intended to rest against the inner surface 10 of the inner space 9. Similarly, these insulating blocks 11 have a flat internal surface forming a support surface for receiving a waterproof membrane.

However, the supporting structure 1 has in practice dimensions which may vary from the theoretical dimensions. It is therefore necessary to take into account the variations in the dimensions of the supporting structure 1 linked for example to construction tolerances to integrate a sealed and thermally insulating tank in the internal space 9.

For this, a three-dimensional measurement of the internal space 9 of the supporting structure 1 is carried out. This three-dimensional measurement of the internal space 9 is carried out by any suitable means, for example by using laser rangefinders or laser emitters and sensors positioned in the internal space 9 in order to measure the dimensions and the arrangement of the various bearing walls. 2, 3, 4, 5.

From this three-dimensional measurement of the internal space 9, a position and dimensions of the tank to be installed in the supporting structure are calculated.

More particularly, the vessel walls are dimensioned and their position determined on the one hand as a function of the dimensions of the insulating blocks 11, and more particularly of the outer surface 12 of said insulating blocks 11, and on the other hand of the three-dimensional measurement of the 'internal space 9. The insulating blocks 11 being anchored juxtaposed in a regular mesh on each

bearing wall

2, 3, 4, 5, anchoring positions of the insulating blocks 11 on the

bearing wall

2, 3, 4, 5 corresponding values are determined for each tank wall.

For each tank wall, a mesh 15 of the insulating blocks 11 is thus calculated. FIG. 2 illustrates an example of a mesh 15 on a transverse carrying wall 2. This mesh 15 comprises a plurality of first positioning lines 16 and a plurality of second positioning lines 17. The first positioning lines 16 are mutually parallel. Likewise, the second positioning lines 17 are mutually parallel. The first positioning lines 16 and the second positioning lines 17 are perpendicular to each other. The first positioning lines 16 are spaced according to a first regular spacing step 18, this first spacing step 18 corresponding to the dimension of a first side of the external surface 12 of an insulating block 11. Likewise, the second positioning lines 17 are spaced apart by a second regular spacing pitch 19, this second spacing pitch 19 corresponding to the dimension of a second side of the outer surface 12 of the insulating blocks 11. These first positioning lines 16 and these second positioning lines 17 correspond to lines along which said insulating blocks 11 are anchored to the transverse bearing wall 2, for example by means of anchoring members, not shown, such as studs. The mesh 15 thus makes it possible to determine the positions of the insulating blocks 11 on the transverse supporting wall 2.

According to one embodiment, a longitudinal central axis (not illustrated), a transverse central axis 13 (see FIG. 2) and a central height axis 14 (see FIG. 2) of the tank are calculated. These central axes are determined according to the three-dimensional measurement of the internal space 9. These central axes are possibly adjusted according to the position of the liquid dome 6 in the supporting structure 1 and make it possible to determine the arrangement of the mesh 15. By example, as illustrated in FIG. 2, the mesh 15 determined for anchoring the insulating blocks 11 on a transverse load-bearing wall 2 can be symmetrical on either side of the central axis of height 14. In addition, the transverse central axis 13 can determine a first positioning line 16.

In the context of a sealed and thermally insulating tank having at least one corrugated waterproof membrane, for example as described in document FR-A-2691520, the meshes 15 on the

various bearing walls

2, 3, 4, 5 are preferably determined so as to ensure continuity in the corrugations between the different walls of the tank. Typically, the positioning of the insulating blocks 11 on two

adjacent bearing walls

2, 3, 4, 5 are modulated so as to form support surfaces allowing installation of the waterproof membrane so that the corrugations can be continuous between the walls of tanks.

However, the internal surface 10 formed by the supporting

walls

2, 3, 4, 5 may have imperfect flatness due, for example, to construction tolerances or even to the assembly of the various elements forming said supporting

walls

2, 3, 4 5 Thus, for example, the welds made between two portions of a double shell assembled together can constitute zones of irregularity in the flatness of the internal surface 10. Likewise, the zones comprising stiffeners arranged between the two walls forming the double shell. of a ship can also form areas of irregularity in the flatness of the internal surface 10.

These defects in the flatness of the internal surface 10 must be remedied during the installation of the insulating blocks 11. In fact, the vessel walls are subject to significant stresses in use, for example under the effect of deformations of the supporting structure 1 linked to navigation, under the effect of thermal stresses or even under the effect of movements of liquid in the tank. To avoid degradation of the seal of the tank, the waterproof membranes are arranged as flat as possible. It is therefore important that the primary and secondary thermally insulating barriers form flat and continuous support surfaces for the waterproof membranes. The flatness defects in the internal surface 10 must therefore be remedied in order to provide a satisfactory support surface for the insulating blocks 11 on which the waterproof membranes of the tank rest.

FIG. 3 illustrates a transverse load-bearing wall 2 exhibiting such flatness defects. These flatness defects generate more or less significant differences between the points of the internal surface 10 and a flat mean line of the bearing wall.

In order to make up for these deviations 20, a reference plane 21 is determined corresponding to an ideal position of the waterproof membrane, that is to say an ideal position of the internal surface 22 of the insulating blocks 11. This reference plane 21 illustrated in FIG. 4 is substantially parallel to a mean plane of the transverse load-bearing wall 2, that is to say it corresponds to a plane parallel to the transverse load-bearing wall 2, apart from the aforementioned flatness defects. In this figure 4 are also illustrated the first positioning lines 16.

The reference plane 21 is an optimal theoretical plane. It can be tolerated that the insulating blocks 11 have an internal surface 22, that is to say a support surface for a primary or secondary waterproof membrane, exhibiting a slight inclination with respect to this reference plane 21. Each insulating block 11 has an internal surface 22 exhibiting with the optimum reference plane 21 an angle less than Arctan (10 ^-2 ), and preferably less than Arctan (6.10 ^-3 ). In addition, the internal surface 22 of two adjacent insulating blocks 11 must not form an angle that is too large and preferably less than Arctan (10 ^-2 ), and preferably less than Arctan (6.10 ^-3 ). These angles correspond to a limit beyond which the support surface of the waterproof membrane would have insufficient flatness and likely to generate in use one or more areas of stress concentration on the waterproof membrane.

As illustrated in FIG. 5 showing a sectional view perpendicular to the first positioning lines 16, a reference line 23 is interpolated by linear portions 24 from the reference plane 21 for each second positioning line 17. Each linear portion 24 has a dimension corresponding to the first spacing step, in other words, each linear portion corresponds to the side dimension of an insulating block 11. This interpolation is carried out in a similar manner for each first positioning line with linear portions corresponding to the second step spacing.

In order to ensure the anchoring of the insulating blocks 11 in a position corresponding to the corresponding linear portion 24 of the reference line 23, shims 25 are arranged on or near the anchoring members intended to cooperate with the insulating blocks 11. These wedges 25 are dimensioned so as to have a constant gap, equal to the thickness of an insulating block 21, between the internal surface of said wedges 25 and the reference line 23.

In addition, as illustrated in Figure 6, beads of mastic 26 are interposed between the outer surface 12 of the insulating blocks 11 and the inner surface 10. These cords of mastic 26 are made by mixing a polymerizable resin and a hardener on the site of manufacture of the tank in order to be applied immediately, before curing by polymerization, on the insulating blocks 11. This manufacture on site is necessary if the curing time of the mastic is relatively short, for example about 1 hour or less.

These beads of mastic 26 make it possible to make up for the defects of flatness of the internal surface 10 and to provide a support for the insulating blocks 11 between the shims 25. For this, the cords of mastic 26 are dimensioned to fill the gaps 27 between the external surface 12 of the insulating blocks 11 and the internal surface 10 while having a surface of cooperation with, on the one hand, the insulating blocks 11 on which they are applied and, on the other hand, the internal surface 10 of the supporting structure sufficient to support said insulating blocks 11 and transmit the forces between the insulating blocks 11 and the supporting structure 1. In other words, these beads of mastic 26 are dimensioned according to the distances 27 measured between the outer surface 12 of the insulating blocks 11 and the internal surface 10 and as a function of a predefined width of said cooperation surface.

Thus, the quantity of mastic deposited in a malleable state to form a bead of mastics 26 is therefore dimensioned with a sufficient cross section so that, in the final state, after crushing of said bead of mastic 26 between the outer surface 12 of the insulating block 11 and the internal surface 10 when placing said insulating block 11 on the supporting structure 1, an application surface of said bead of mastic 26 on the insulating block 11 and on the internal surface 10 has a width greater than or equal to a width minimum predefined.

The dimensioning of the cross section of the mastic beads is therefore determined from the predefined minimum width and the positions of the mastic beads, since the thickness dimension of a bead depends on the gap 27 to be filled at its precise location. . These positions (and therefore the number of mastic beads 26 to be laid) as well as this predefined width result from a preliminary calculation taking into account the mechanical bending strength of the insulating blocks 11.

The deviations 27 are measured on the one hand on the reference lines 23 and on the other hand on the three-dimensional measurement of the internal surface 10 carried out previously. More particularly, for the anchoring position of each insulating block 11 determined by the mesh 15, a plurality of gaps 27 between the outer surface 12 of said insulating block 11 and the inner surface 10 of the supporting structure 1. In the example illustrated in Figure 6, three cords of mastic 26 are interposed between each insulating block 11 and the internal surface 10 of the supporting structure 1, these cords of mastic developing over the entire length of the insulating block 11. Thus, one or more gaps 27 are measured along each line of the outer surface 12 of the insulating blocks at which the sealant beads 26 are to be applied. Furthermore, these deviations 27 are measured in a direction of thickness of the corresponding tank wall. In other words, the deviation is measured at one or more measuring points, for example three measuring points, for each bead of sealant. If several measurement points are associated with the same bead of mastic, the sizing of the bead of mastic can be carried out variably in the length of the bead of mastic, or uniformly over the entire length of the bead of mastic at an average value. of the deviations obtained at these measurement points.

According to one embodiment, such cords of mastic 26 are produced continuously by means of a mastic extruder. Various techniques can be used to adjust the cross section of the sealant beads 26 during manufacture.

Adjustment of the cross section can be achieved by adjusting the flow rate of sealant through the dispensing head of the extruder. This flow rate adjustment can optionally be accompanied by an adjustment of the outlet section of the extruder dispensing head. This adjustment of the outlet section can be carried out in different ways, for example by means of an adjustable section distribution head or by means of interchangeable distribution heads, having different fixed sections.

Another way to adjust the cross section of the bead of mastic, especially if the mastic is sufficiently thixotropic, is to adjust a relative feed rate between the dispensing head of the extruder and the surface on which the bead of mastic is deposited. , that is to say for example by adjusting the travel speed of the insulating blocks in the technique described by the publication FR-A-2259008.

A first method of dimensioning the sealant beads consists in dimensioning the cross section of each bead of mastic 26 to measure, as a function of the distance 27 measured at the location that the bead of mastic must occupy on the supporting structure 1. However, , such a sizing method has the drawback of having to permanently modify the setting of the production tool. Thus, the sealant beads cannot be made uniformly.

To remedy this drawback, another method of dimensioning the sealant beads consists in providing a determined number t of discrete sizes. This embodiment, although it results in a greater consumption of mastic than the embodiment described above in which each bead of mastic 26 is manufactured individually according to its location in the tank, makes it possible to simplify the manufacture of the mastic. bead of sealants 26 by defining uniform sizes thus not requiring an adaptation of the production tool for each bead of sealant 26 manufactured. For this, several methods will be described with reference to Figure 7.

FIG. 7 illustrates a distribution 28 of the deviations 27 measured as described above. The ordinate represents the dimension of the gap 27 in the direction of thickness of the vessel wall. This dimension can be multiplied by the predefined width to obtain the ideal cross-sectional area of the bead of sealant. The abscissa represents the population of the measurement points, reduced to a percentage. The distribution has been ordered in ascending order of deviations 27 and thus provides the frequency of occurrence of each deviation in the distribution. The more frequent a deviation, the more it occupies a large place in the distribution 28.

According to this embodiment, cords of sealants 26 are produced in different sizes for all of the distances 27 measured between the internal surface 10 and the external surface of the tank, typically the external surface 12 of the insulating blocks 11. This distribution deviations could however be determined at the scale of a building unit other than a whole tank, for example a flat wall of the tank.

In this figure, the distribution 28 of the deviations can be increased by a certain safety coefficient, for example increased by approximately 8%, relative to the actual measured value. This increase makes it possible to slightly oversize the sections of the sealant beads 26 to guarantee a satisfactory cooperation surface, that is to say in particular to obtain by creep a final width greater than or equal to the predefined width. A second curve 29 corresponds to a polynomial interpolation of the distribution 28 of the deviations.

In a first variant of this embodiment, the sizes of the sealant beads 26 are determined equally. In the example illustrated in figure 7, five sizes (ie t = 5) of sealant beads 26, designated by the numbers 31 to 35, are determined so that each size of the sealant beads allows to cover 20% of the distribution 28 of the deviations. A curve of equally distributed sizes 30 illustrates in dotted lines the different sizes 31 to 35. Thus, on this curve 30, a first evenly distributed size 31 has a thickness of 5.7mm, a second equally distributed size 32 has a thickness of 8.4mm, a third size evenly distributed 33 has a thickness of 10.3mm, a fourth evenly distributed size 34 has a thickness of 12.9mm and a fifth evenly distributed size 35 has a thickness of 23mm. Corresponding cross sections can be obtained by multiplying these thicknesses by the predefined width.

Accordingly, in the example of evenly distributed sizes shown in dotted lines in Figure 7, an equal number of beads of sealant is used in each of sizes 31 to 35. At locations where the gaps 27 are less than 5.7mm, that is. i.e. the smallest 20% measured deviations, sealant beads 26 of the first evenly distributed size 31 are used. At locations where the gaps 27 are between 5.7mm and 8.4mm, i.e. also 20% of the measured gaps, sealant beads 26 according to the second size evenly distributed 32 are used, etc.

Such evenly distributed

sizes

31, 32, 33, 34 and 35 facilitate the manufacture of the sealant beads 26 and make it possible to make up all of the measured deviations 27 simply, quickly and reliably.

However, these evenly distributed sizes are not suitable for the manufacture of all tanks. The flatness defects of the internal surface 10 being different from one tank to another, these evenly distributed sizes can generate an excessive consumption of mastic when the deviations 27 are mainly far from the dimensions of the equally distributed

sizes

31, 32, 33, 34 and 35. For example, with respect to curve 30, the fifth evenly distributed size 35 of sealant beads 26 is very significantly greater than the difference 27 measured for a large part of the measurement points which will be associated with said fifth size 35 of beads. of mastic 26, causing a significant excess consumption of mastic, that is to say in particular an excess width due to excessive creep of the bead of mastic. In an extreme case, the resulting excess width could completely fill the gap between the bead of mastic 26 and an adjacent bead of mastic, and thus create an air pocket trapped in the mastic. In the event that the tank must contain flammable materials, such an air pocket may be prohibited by regulations.

According to a second variant of this embodiment, the discrete sizes of the sealant beads are determined as a function of the frequency of occurrence of the measured deviations 27, so as to limit an accumulated difference between the deviations 27 and said associated sizes.

The term “limiting a cumulative difference” is understood to mean the fact of obtaining a better dimensioning of the beads of mastic compared with the evenly distributed sizes. For this, it is necessary to minimize the area 37 located between the distribution 28 of the deviations and the notched curve 36 representing the discrete sizes of the beads, that is to say the integral value of the difference between the two curves. This problem can be solved with numerical optimization methods. .

It is possible to increase the number t of sizes of beads so as to limit the losses of mastic during the manufacture of the beads of mastic 26. Likewise, it is possible to take out certain measuring points in order to truncate the distribution 38, and thus handle exceptional deviations manually. For example, custom sealant beads can be used for a portion of up to 2% of the measured deviations (larger sealant beads). In this case, the t sizes of mastic beads determined as above are used for the remainder of the measured deviations.

The technique described above for producing a sealed and thermally insulating tank can be used in various types of tanks, for example to constitute an LNG tank in an onshore installation or in a floating structure such as an LNG or other vessel.

Referring to Figure 8, a cutaway view of an LNG carrier 70 shows a sealed and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The wall of the vessel 71 comprises a primary waterproof barrier intended to be in contact with the LNG contained in the vessel, a secondary waterproof barrier arranged between the primary waterproof barrier and the double hull 72 of the ship, and two insulating barriers arranged respectively between the vessel. primary watertight barrier and the secondary watertight barrier and between the secondary watertight barrier and the double shell 72.

In a manner known per se, loading / unloading pipes 73 arranged on the upper deck of the ship can be connected, by means of suitable connectors, to a maritime or port terminal for transferring a cargo of LNG from or to the tank 71.

FIG. 8 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipe 76 and an onshore installation 77. The loading and unloading station 75 is a fixed off-shore installation comprising an arm. mobile 74 and a tower 78 which supports the mobile arm 74. The mobile arm 74 carries a bundle of insulated flexible pipes 79 which can be connected to the loading / unloading pipes 73. The mobile swivel arm 74 adapts to all sizes of LNG carriers . A connecting pipe, not shown, extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG carrier 70 from or to the onshore installation 77. The latter comprises liquefied gas storage tanks 80 and connecting pipes 81 connected by the underwater pipe 76 to the loading or unloading station 75. The underwater pipe 76 allows the transfer of the liquefied gas between the loading or unloading station 75 and the shore installation 77 over a great distance, for example 5 km, which makes it possible to keep the LNG carrier 70 at a great distance from the coast during loading and unloading operations.

In order to generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and / or pumps fitted to the shore installation 77 and / or pumps fitted to the loading and unloading station 75 are used.

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 includes all the technical equivalents of the means described as well as their combinations if these come within the scope of the invention.

The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or other steps than those stated in a claim. The use of the indefinite article "a" or "a" for an element or a stage does not exclude, unless otherwise indicated, the presence of a plurality of such elements or stages.

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

Claims

Method of manufacturing cords of mastics (26) intended to install a sealed and thermally insulating tank in a supporting structure (1), the supporting structure (1) comprising an internal surface (10) defining an internal space (9),
the process comprising the steps of:
- determining a plurality of gaps (27) between a plurality of measurement points distributed over an external surface of the tank and the internal surface (10) of the supporting structure (1), said gaps (27) being determined parallel to a direction of thickness of the tank at the level of said measuring points, said distances (27) being determined as a function of an implantation position of the tank in the internal space (9) of the supporting structure (1) and of three-dimensional dimensions of said tank and said internal space (9) of the supporting structure (1),
- providing a plurality of sizes (31, 32, 33, 34, 35, 36) of cross section, said plurality of sizes (31, 32, 33, 34, 35, 36) comprising an integer t of sizes (31, 32, 33, 34, 35, 36), the integer t being less than a total number of said gaps of the plurality of gaps (27), the plurality of sizes (31, 32, 33, 34, 35, 36) having an upper bound, said upper bound being greater than a rectangular section associated with the maximum deviation of the plurality of deviations (27), the associated rectangular section having a predefined width and a height equal to the maximum deviation of the plurality of deviations (27),
- manufacturing beads of mastic (26) intended to be applied between the internal surface (10) of the supporting structure (1) and the external surface of the tank, said beads having dimensions of cross section defined as a function of said gaps (27 ) determined, the cords of sealants (26) being fabricated with cross-sectional dimensions selected from said plurality of sizes (31, 32, 33, 34, 35, 36).
A manufacturing method according to claim 1, wherein for one deviation of the plurality of deviations (27), a bead of mastic (26) is produced having a cross-sectional dimension equal to a minimum size among the sizes (31). , 32, 33, 34, 35, 36) which is greater than or equal to a rectangular section associated with said gap, the associated rectangular section having said predefined width and a height equal to said gap.
The manufacturing method according to claim 1 or 2, wherein the step of providing the plurality of cross-sectional sizes (36) comprises:
- calculating a frequency of occurrence of the deviations of the plurality of deviations (27),
- calculating the plurality of sizes (36) of sealant beads as a function of the frequency of occurrence of the deviations and the deviations (27) determined so that each deviation of the plurality of deviations (27) can be associated with a size of the plurality of sizes (36) which is immediately greater than the rectangular section associated with said gap, and so as to limit an accumulated difference between the rectangular sections associated with said gaps of the plurality of gaps (27) and said sizes ( 36) to which said deviations are associated.
Manufacturing process according to one of claims 1 to 3, wherein the fixing of the integer t and / or the calculation of the plurality of sizes is carried out for a construction unit chosen from a plurality of tanks, a single tank, a flat wall of a polyhedral tank, and a portion of a flat wall.
Manufacturing process according to one of claims 1 to 4, wherein the whole number t of sizes is less than or equal to 10, preferably less than or equal to 5.
Manufacturing process according to one of claims 1 to 5, further comprising:
- carry out a three-dimensional measurement of the internal space (9) of the supporting structure (1),
- defining dimensions and a shape of the tank as a function of said three-dimensional measurement so as to allow the insertion of said tank into the internal space (9) of the supporting structure (1),
- define the installation position of the tank in the internal space (9) of the supporting structure (1) according to the three-dimensional measurement of the internal space (9) of the supporting structure (1) and the dimensions and the shape of the tank defined.
The manufacturing method according to claim 6, wherein the vessel comprises a plurality of insulating blocks (11) comprising bottom panels defining said outer surface of the vessel, and wherein defining an implantation position of the vessel comprises defining a position anchoring of the plurality of insulating blocks (11) on the internal surface (10) of the supporting structure (1).
Manufacturing method according to claim 6, wherein the measuring points comprise, for each insulating block (11), a point of a bottom panel of said insulating block (11) when said insulating block (11) is in position d 'anchoring.
Manufacturing process according to claim 8, wherein the supporting structure comprises at least one flat supporting wall (2, 3, 4, 5), the vessel comprising a vessel wall comprising a plurality of insulating blocks (11) intended to be anchored on the supporting wall (2, 3, 4, 5), said insulating blocks (11) having an inner surface (22) parallel to the bottom panel, said inner surface (22) forming a support surface for a waterproof membrane of the vessel wall, the method further comprising:
- determine for the load-bearing wall a reference plane (21),
and wherein the anchoring position of the insulating blocks (11) is defined such that the inner surface (22) of said insulating block (11) has, when said insulating block (11) is in the anchoring position, an inclination less than a threshold angle with respect to the reference plane (21).
Manufacturing process according to claim 9, in which the threshold angle is less than Arctan (10 - ²), preferably less than Arctan (6.10 -3 ).
Manufacturing process according to one of claims 7 to 10, wherein the sealant beads (26) are produced with a length less than or equal to a dimension of the bottom panel of an insulating block (11).
Storage installation comprising a supporting structure and a sealed and thermally insulating tank installed in an internal space of the supporting structure, said storage installation comprising cords of sealants (26) manufactured according to one of claims 1 to 11 applied between a surface internal space of the supporting structure and an external surface of the vessel.
Storage facility according to claim 12, in the form of a vessel (70) for transporting a cold liquid product, the vessel comprising a double hull forming said supporting structure.
Transfer system for a cold liquid product, the system comprising a storage installation according to claim 13, insulated pipes (73, 79, 76, 81) arranged so as to connect the tank (71) installed in the hull of the ship to a floating or terrestrial storage facility (77) and a pump for driving a flow of cold liquid product through insulated pipelines from or to the floating or terrestrial storage facility to or from the vessel's tank.
A method of loading or unloading a storage facility according to claim 34, wherein a cold liquid product is conveyed through insulated pipelines (73, 79, 76, 81) from or to a floating or land storage facility (77 ) to or from the vessel's tank (71).