EP4019388B1 - Vessel comprising a tank - Google Patents

Description

Technical area

The invention relates to the field of ships comprising tanks, and in particular waterproof and thermally insulating tanks with membranes. In particular, the invention relates to the field of ships comprising 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). ) presenting for 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. The tank can be intended for the transport of liquefied gas or to receive liquefied gas serving as fuel for the propulsion of the ship.

Technology background

It is known from the prior art so-called double-hulled ships, namely comprising an internal hull and an external hull. These ships may contain one or more tanks containing fuel whether for its transport or for its use as fuel for the propulsion of the ship. These tanks are placed in the internal shell and are fixed to it. These tanks can for example be waterproof and thermally insulating membrane tanks for the storage of a liquefied gas. In this case, the walls of such a tank comprise a multilayer structure superimposed in a thickness direction and comprising at least one sealing membrane and at least one thermally insulating barrier located between the internal shell and the sealing membrane.

For the proper functioning of these tanks, through elements pass through a plurality of orifices made in the internal shell and in the tank walls. These through elements can, for example, be loading/unloading pipes or a sump structure.

The internal shell has on its external surface a network of stiffeners making it possible to stiffen the structure in order to support in particular the pressure of the fluid contained in the tank(s). This network of stiffeners is interrupted all around the orifices made in the internal shell, for example by interrupting or diverting the stiffeners of said network all around the orifice.

However, it has been noted that the beam of a ship which includes such tanks is caused to bend in the longitudinal direction of the ship due to different factors. Indeed, for example, the bending of the ship beam is caused by the passage of the hull from its dry dock state to its floating state, or by variations in the temperature of the hull between the temperature during its manufacture and the temperature during use, or by the forces exerted on the ship by the swell.

By way of example, such vessels are described in particular in patent applications US 2017/219166 A1 , FR 3 035 175 A1 , WO 2016/166481 A2 And FR 3 083 843 A1 .

Summary

The invention starts from the hypothesis that during these bending phenomena, the internal shell is subjected to strong mechanical stresses which are caused to concentrate at the level of the orifices made therein. These stress concentrations can cause deformation of said orifice, called “ovalization” in the case of a circular orifice, which can damage the internal shell and the tank.

An idea underlying the invention is to limit the risk of deformation of an orifice made in the internal shell which could damage it.

• le navire comprenant au moins un élément traversant passant au travers d'une ouverture réalisée dans la coque interne et dans la paroi de la cuve, au moins une tôle de coque bordant ladite ouverture ;
• dans lequel le navire comporte au moins une plaque métallique comprenant au moins un orifice à travers duquel passe l'élément traversant, la plaque métallique ayant une épaisseur supérieure à l'épaisseur de ladite au moins une tôle de coque bordant l'ouverture, la plaque métallique étant soudée à ladite au moins une tôle de coque bordant l'ouverture, la plaque métallique s'étendant autour de l'ouverture (3).

According to one embodiment, the invention provides a ship comprising a metallic internal hull comprising an internal surface and an external surface, an external hull arranged outside the internal hull facing the external surface, and at least one tank arranged in the internal shell and supported against the internal surface of the internal shell, the tank comprising at least one tank wall, the internal shell comprising a plurality of shell sheets welded to each other,

• the ship comprising at least one through element passing through an opening made in the internal hull and in the wall of the tank, at least one hull plate bordering said opening;
• in which the ship comprises at least one metal plate comprising at least one orifice through which the through element passes, the metal plate having a thickness greater than the thickness of said at least one hull plate bordering the opening, the plate metal being welded to said at least one shell sheet bordering the opening, the metal plate extending around the opening (3).

Thanks to these characteristics, the metal plate of the ship, due to its greater thickness than the internal hull, makes it possible to stiffen the structure all around the orifice in order to limit its deformation during bending of the ship's beam.

According to embodiments, such a vessel may include one or more of the following characteristics.

The thickness of the metal plate and the shell plates is measured in a direction orthogonal to the outer surface of the inner shell.

According to one embodiment, the ship comprises a plurality of through elements passing through said opening made in the internal hull and in said tank wall, the metal plate comprising an orifice for each through element.

According to one embodiment, the vessel comprises a plurality of through elements passing through a plurality of openings made in the internal shell and in said tank wall, and the vessel comprises a plurality of metal plates each comprising at least one orifice through which one of the through elements passes, the metal plates being spaced from each other by at least one shell sheet.

According to one embodiment, the thickness of the metal plate is greater than or equal to 1.2 times the thickness of the at least one shell sheet bordering the opening.

Thus, the metal plate is thick enough to diffuse the stresses and stiffen the structure all around the orifice, without making the welding operation between the two elements too complex and limiting the deformations linked to welding.

According to one embodiment, the metal plate is made of stainless steel and the hull sheets are made of carbon steel.

According to one embodiment, the orifice is circular and the through element has a circular section.

According to one embodiment, the ship comprises a first network of stiffeners welded to an external surface of the metal plate, and a second network of stiffeners welded to the external surface of the internal hull; And
in which the first network of stiffeners comprises internal stiffeners and external stiffeners, the external stiffeners being arranged so as to form a stiffener frame all around the internal stiffeners, stiffeners of the second network of stiffeners being welded to the external stiffeners.

Thus, just like the thickness of the metal plate, the first network of stiffeners makes it possible to stiffen the structure all around the orifice so as to limit any deformation thereof due, for example, to the bending of the ship beam. In addition, the first network of stiffeners ensures mechanical continuity with the second network of stiffeners.

According to one embodiment, each external stiffener is made in the form of a plate.

According to one embodiment, the stiffeners of the first network of stiffeners are made of stainless steel, and the stiffeners of the second network of stiffeners are made of carbon steel.

According to one embodiment, the internal stiffeners are distributed regularly all around the through element.

Here we mean “regularly distributed” as being spaced from each other according to a constant pitch, here a constant angular pitch.

According to one embodiment, the internal stiffeners are distributed irregularly all around the through element.

Here we mean “irregularly distributed” as being spaced from each other according to a variable pitch, here a variable angular pitch.

According to one embodiment, the second network of stiffeners comprises primary stiffeners and secondary stiffeners, each primary stiffener being formed essentially in a plane orthogonal to the external surface of the internal shell and being welded on the one hand to the internal shell and on the other hand to the external shell, and each secondary stiffener being arranged essentially in a plane orthogonal to the external surface of the internal shell and being welded to the internal shell and formed at a distance from the external shell.

According to one embodiment, the tank wall is a ceiling wall of the tank and the through element is a pipe.

According to one embodiment, the internal stiffeners are welded on the one hand to the metal plate and on the other hand to the external stiffeners.

According to one embodiment, the internal stiffeners are made in the form of a gusset and have an increasing thickness of the pipe towards the external stiffeners.

The thickness of the stiffeners is measured in a direction orthogonal to the external surface of the internal shell

According to one embodiment, the growth in the thickness of the internal stiffeners is linear, quadratic or exponential, until reaching a thickness equal to the distance between the metal plate and the external shell.

The thickness of the internal stiffeners is measured in the same way as for the metal plate, that is to say in a direction orthogonal to the external surface of the internal shell.

According to one embodiment, the first network of stiffeners comprises at least three internal stiffeners, preferably eight internal stiffeners, being preferably distributed regularly all around the orifice.

According to one embodiment, each internal stiffener is fixed on a portion of an external stiffener, a stiffener of the second series of stiffeners being fixed in said portion of an external stiffener.

According to one embodiment, the ceiling wall comprises a thermally insulating barrier supported by the internal shell, and a sealing membrane supported by the thermally insulating barrier, the thermally insulating barrier and the sealing membrane being interrupted at a distance from the pipe, the sealing membrane being fixed to the metal plate via a connection ring all around the pipe, the connection ring comprising a portion projecting from the external surface of the metal plate so as to form a circular stiffener.

According to one embodiment, at least one end of the internal stiffeners is welded to the circular stiffener.

According to one embodiment, the external stiffeners are formed in a plane orthogonal to the external surface of the internal shell, the external stiffeners being welded on the one hand to the metal plate and on the other hand to the external shell.

According to one embodiment, the internal stiffeners have a lower surface in contact with the metal plate, said surface extending from the circular stiffener to the external frame.

According to one embodiment, the internal stiffeners have a lateral surface in contact with one of the external stiffeners, said surface extending from the metal plate to the external shell.

According to one embodiment, the tank wall is a bottom wall of the tank and the through element is a sump structure or a support foot for a loading/unloading mast.

According to one embodiment, the stiffener frame is an external stiffener frame, the internal stiffeners comprise a first group of stiffeners, and a second stiffener group, the first stiffener group forming an internal stiffener frame all around the orifice and inside the external stiffener frame, the internal stiffener frame being welded to the external stiffener frame, the second stiffener group comprising at least two junction stiffeners, the junction stiffeners being on the one hand welded to the sump structure and on the other hand welded to the internal stiffener frame.

According to one embodiment, the stiffener frame is an external stiffener frame, the internal stiffeners comprise a first stiffener group, a second stiffener group and a third stiffener group, the first stiffener group forming a first stiffener frame all around the orifice and inside the outer stiffener frame, the first stiffener frame being welded to the outer stiffener frame, the second stiffener group forming a second stiffener frame all around the orifice and at the inside the first stiffener frame, the second stiffener frame being welded to the first stiffener frame, the third stiffener group comprising at least two junction stiffeners, the junction stiffeners being on the one hand welded to the sump structure and on the other hand welded to the second stiffener frame.

According to one embodiment, the junction stiffeners are distributed regularly all around the sump structure.

According to one embodiment, the third group of stiffeners comprises four junction stiffeners.

According to one embodiment, the sump structure comprises a sump bottom and the vessel comprises two sump stiffeners, the sump stiffeners being welded to an external surface of the sump bottom.

According to one embodiment, the sump stiffeners intersect in the center of the sump bottom and are oriented relative to each other at 90°.

According to one embodiment, each sump stiffener is oriented at 45° relative to one of the junction stiffeners.

According to one embodiment, the tank is a waterproof and thermally insulating membrane tank intended for the storage of a liquefied gas.

According to one embodiment, the tank wall comprises a multilayer structure formed in a thickness direction from the outside towards the inside of the tank of a secondary thermally insulating barrier supported by the internal shell, of a membrane of secondary sealing supported by the secondary thermally insulating barrier, of a primary thermally insulating barrier supported by the membrane secondary sealing, and a primary sealing membrane supported by the primary thermally insulating barrier and intended to be in contact with the liquefied gas.

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 internal hull of the vessel to a storage installation floating or terrestrial and a pump for driving a flow of cold liquid product through the insulated pipes from or to the floating or terrestrial storage installation to or from the vessel tank.

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

Brief description of the figures

• [Fig. 1] La figure 1 représente une vue de côté écorchée d'un navire à double coque comprenant une pluralité de cuves.
• [Fig. 2] La figure 2 est une vue en perspective du détail II de la figure 1, la coque interne du navire étant traversée par deux conduites.
• [Fig. 3] La figure 3 est une vue de dessus schématique du détail II de la figure 1, la coque interne du navire étant traversée par une conduite.
• [Fig. 4] La figure 4 est une vue en coupe schématique du détail IV de la figure 1, la coque interne étant traversée par une structure de puisard.
• [Fig. 5] La figure 5 est une vue de dessous schématique du détail IV de la figure 1.
• [Fig. 6] La figure 6 est une représentation schématique écorchée d'un navire méthanier comprenant une pluralité de cuve et d'un terminal de chargement/déchargement de cette cuve.

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

• [ Fig. 1 ] There figure 1 represents a cutaway side view of a double-hulled ship comprising a plurality of tanks.
• [ Fig. 2 ] There figure 2 is a perspective view of detail II of the figure 1 , the internal hull of the ship being crossed by two pipes.
• [ Fig. 3 ] There Figure 3 is a schematic top view of detail II of the figure 1 , the internal hull of the ship being crossed by a pipe.
• [ Fig. 4 ] There Figure 4 is a schematic sectional view of detail IV of the figure 1 , the internal shell being crossed by a sump structure.
• [ Fig. 5 ] There Figure 5 is a schematic bottom view of detail IV of the figure 1 .
• [ Fig. 6 ] There Figure 6 is a cut-away schematic representation of an LNG ship comprising a plurality of tanks and a loading/unloading terminal for this tank.

Description of embodiments

In the description below, a ship 70 will be described comprising an internal hull 1, an external hull 2, and a plurality of storage tanks 71.

There figure 1 represents more particularly a 70 methane tanker vessel for the storage and transport of liquefied gas. However, the invention is not limited to this type of ship and concerns any ship 70 with a double hull 1, 2 equipped with at least one tank comprising a fuel whether for its transport or its use as fuel.

Thus, the ship 70 represented on the figure 1 comprises four tanks arranged in the internal shell 1 and fixed to it. The internal shell 1 is produced by assembling a plurality of shell sheets 16 to each other. For the proper functioning of these tanks, openings 3 are provided through the internal shell 1 in order to pass equipment from the tank. Through elements, such as for example a sump structure 9 shown in particular on the figures 4 and 5 or a pipe 20 represented in particular on the figures 2 And 3 , are thus arranged inside these openings 3 in the internal shell 1.

In relation to the figure 2 , we observe that the ship 70 includes a metal plate 30 in order to make the connection between the through element 9, 20 and the internal hull 1 at the level of the opening 3. The metal plate 30 is thus welded to the hull plates while around the opening 3 and has an orifice 31 through which the through element 9, 20 passes. The through element 9, 20 is fixed to the metal plate 30 all around the orifice 31. The metal plate 30 is flat and arranged substantially in the plane of the shell plates of the internal shell 1 bordering the opening 3.

As presented above, it is advantageous at the level of the orifices 31 to stiffen the structure formed by the internal shell 1 and the metal plate 30 in order to limit any deformation of the orifice 31.

For this, the thickness of the metal plate 30 has been increased compared to the thickness of the shell sheets 16 of the internal shell 1 bordering the opening 3. For example, the thickness of the metal plate 30 is thus 1, 5 times greater than the thickness of the shell sheets 16 bordering the opening 3. In order to further improve the rigidity of the metal plate 30 without too significantly increasing the thickness of the metal plate 30, a first network stiffener 32 is welded to the metal plate 30. The first stiffener network 32 will be described in more detail below according to several embodiments depending on the type of through element.

The internal shell 1 has on its external surface a second network of stiffeners 17, as visible in particular on the figure 2 . The second stiffener network makes it possible to stiffen the internal shell 1 so as to support the pressure of the fluid contained in the tank. The second stiffener network 17 comprises primary stiffeners 18 and secondary stiffeners 19 alternating with each other. THE Primary stiffeners 18 and secondary 19 develop in a first series in the longitudinal direction of the ship and also in a second series in the transverse direction of the ship for the upper and lower walls of the internal hull 1.

In another embodiment, the primary stiffeners 18 develop in the longitudinal direction and the secondary stiffeners 19 develop in the transverse direction.

Each primary stiffener 18 is formed in a plane orthogonal to the external surface of the internal shell 1 and is welded on the one hand to the internal shell 1 and on the other hand to the external shell 2 so as to make the junction between the shells 1, 2. Each secondary stiffener 19 is also in a plane orthogonal to the external surface of the internal shell 1, however these are smaller than the primary stiffeners 18 and are therefore welded only to the internal shell 1 and consequently, arranged at a distance from the outer shell 2. The primary stiffeners 18 are in the form of a plate and are advantageously provided with orifices in order to allow the free circulation of operators or of the air present in the space between the inner shell 1 and the outer shell 2.

THE figure 2 And 3 represent embodiments in which the through element is a pipe 20 which passes through the upper wall of the internal shell 1 and the ceiling wall of the tank 71, the figure 2 being a particular case where two pipes 20 pass through the internal shell 1 while being close to each other.

In the embodiments of figure 2 And 3 , the ceiling wall 4 comprises a multilayer structure not shown and comprising at least one thermally insulating barrier supported by the internal surface of the internal shell 1, and at least one sealing membrane supported by the thermally insulating barrier. The thermally insulating barrier and the sealing membrane are interrupted at a distance from the pipe 20. The sealing membrane is fixed to the metal plate 30 via a connection ring (not shown) all around the pipe 20. The connection ring comprises a portion projecting from the external surface of the metal plate 30 so as to form a circular stiffener 21 formed all around the pipe 20 at a distance therefrom. The circular stiffener 21 makes it possible to stiffen the fixing zone of the sealing membrane in order to prevent the metal plate 30 from bending in this zone because of the stresses exerted by the sealing membrane.

On the figures 2 And 3 , the arrangement of the first stiffener network 32 formed on the external surface of the metal plate 30 in the case of a pipe 20 is shown. The first stiffener network 32 comprises internal stiffeners 34 and stiffeners external stiffeners 33. The external stiffeners 33 are made in the form of a plate and arranged so as to form a stiffener frame all around the internal stiffeners 34. The external stiffeners 33 are arranged in a plane orthogonal to the external surface of the upper wall of the internal shell 1. The external stiffeners 33 are welded on the one hand to the metal plate 30 and on the other hand to the external shell 2. In addition, stiffeners of the second network of stiffeners 17 are welded to the external stiffeners 33. In the embodiments shown, primary stiffeners 18 of the second stiffener network 17 are fixed in the extension of the external stiffeners 33.

As shown on the figures 2 And 3 , the internal stiffeners 34 are eight in number and are distributed regularly all around the pipe 20. Indeed, in this example, the internal stiffeners 34 are oriented radially with respect to the axis of the pipe 20 and distributed every 45 ° taking as reference the axis of pipe 20, as visible in Figure 3 . However, the number of internal stiffeners 34 may vary in particular depending on the diameter of the pipe 20 so that their number may be less or greater, as long as they are regularly distributed all around the pipe 20.

The internal stiffeners 34 have a gusset shape and are welded to one of the external stiffeners 33, to the metal plate 30 and to the circular stiffener 21. Thus, the internal stiffeners 34 have a lower surface in contact with the metal plate 30 and welded to it. This upper surface extends from the circular stiffener 21 to the external stiffener 33. In addition, the internal stiffeners 34 have a lateral surface in contact with the external stiffener 33 and welded to it. This lateral surface extends from the metal plate 30 to the external shell 2. Thus, in this configuration, two internal stiffeners 34 are welded to each external stiffener 33. Each internal stiffener 34 is therefore fixed on a portion of a external stiffener 33 and a stiffener of the second series of stiffeners 17 is fixed at this portion of the external stiffener 33 so as to be located in the extension of the internal stiffener 34, as shown in the Figure 3 .

This arrangement of the circular stiffener 21, the internal stiffeners 34, the external stiffeners 33 and the second stiffener network 17 makes it possible to ensure continuity of the mechanical recovery of the forces and a homogeneous distribution of these forces in order to limit the deformation of the orifice 31 of the metal plate 30.

The internal stiffeners 34 have an increasing thickness from the circular stiffener 21 towards the external stiffener 33 in order to best absorb the forces exerted around the orifice 31 of the metal plate 30 and to transfer them homogeneously from the circular stiffener 21 to the external stiffeners 33. In the embodiment shown, this growth is exponential starting from a value less than the height of the circular stiffener 21 to reach a thickness equal to the distance between the metal plate 30 and the external shell 2.

In the particular case of the figure 2 where two pipes 20 pass through the internal shell 1 while being close to each other, the first stiffener network 32 of the first pipe 20 and the first stiffener network 32 of the second pipe 20 share the same external stiffener 33. Thus, on the figure 2 , two pipes 20 pass through the same opening 3 so that only one metal plate 30 is necessary. This metal plate 30 is therefore provided with two orifices 31 and two first stiffener networks 32 are fixed thereon. As shown on the figure 2 , the metal plate 30 can have a rectangular shape, this shape can vary depending on the number of through elements 9, 20. For example, in the case of three through elements 9, 20 passing through the same metal plate 30, that -this can have an L shape.

In the case, not shown, where the two or more through elements 9, 20 are spaced apart from each other and it is necessary to have a plurality of openings 3 in the internal shell 1 and in the tank wall 4 , it is planned to have a metal plate 30 for each of the openings 3. Each of these metal plates 30 is also provided with the necessary number of orifices 31 depending on the number of through elements 9,20 passing through said opening 3 .

THE figures 4 and 5 represent an embodiment in which the through element is a sump structure 9 which passes through the bottom wall of the tank and the lower wall of the internal shell 1.

On the Figure 4 , the multilayer structure of the bottom wall 4 of the tank has been schematically represented in the case where the tank is a sealed and thermally insulating tank with membranes for the storage of liquefied gas. Thus in this embodiment, the walls 4 of the tank are formed by a multilayer structure fixed to the supporting walls of the internal shell 1 and including two waterproof membranes 5, 7 alternating with two thermally insulating barriers 6, 8. As For example, such membrane tanks are described in particular in patent applications WO14057221 , FR2691520 And FR2877638 respectively targeting the Mark V ^© , Mark III ^© and NO96 ^© products developed by the applicant.

The tank wall 4 is mounted on the internal hull 1 of a double-hulled ship 70. The tank wall 4 has a multilayer structure successively including a secondary thermal insulation barrier 8 fixed on the internal shell 1, a membrane secondary sealing membrane 7 supported by the secondary thermal insulation barrier 8, a primary thermal insulation barrier 6 covering the secondary sealing membrane 7 and a primary sealing membrane 5 supported by the primary thermal insulation barrier 6 .

The sump structure 9 comprises a first container 10 in communication with the interior of the tank, and a second container 11 containing the first container 10. The first container 10 is connected continuously to the primary sealing membrane 5, which it thus completes in a watertight manner. Likewise, the second container 11 is connected continuously to the secondary sealing membrane 7, which it thus completes in a watertight manner. The connection between the first container 10 and the primary sealing membrane 5 is made using a first collar 13 while the connection between the second container and the secondary sealing membrane 7 is made using a second collar 14.

The sump structure 9 is also provided with a rigid container 12 which is fixed all around the metal plate 30 at the orifice 31. The first and second containers 10, 11 are located inside the container rigid 12. The rigid container 12, the first container 10 and the second container 11 are for example coaxial cylindrical containers as shown in Figure 4 . The second container 11 is fixed using fixing wings 15 to the metal plate 30. The fixing wings 15 can advantageously have a degree of freedom in translation corresponding to a radial direction of the second container 11 so as to allow contraction and thermal expansion thereof.

In the embodiment of figures 4 and 5 , and in the same way as for the embodiments of the figures 2 And 3 , the first stiffener network 32 comprises internal stiffeners 35, 36, 37 and external stiffeners 33. The external stiffeners 33 are made in the form of a plate and arranged so as to form an external stiffener frame all around the internal stiffeners 35, 36, 37. The external stiffeners 33 are arranged in a plane orthogonal to the external surface of the upper wall of the internal shell 1. The external stiffeners 33 are welded on the one hand to the metal plate 30 and on the other hand to the outer shell 2. In addition, stiffeners of the second network of stiffeners 17 are welded to the external stiffeners 33. In the embodiments shown, primary stiffeners 18 of the second network of stiffeners 17 are fixed in the extension of the external stiffeners 33. Thus, the external stiffeners 33 are arranged in the same way as for the embodiments of the figures 2 And 3 . However, the arrangement of the primary stiffeners 35, 36, 37 for the embodiment of the figures 4 and 5 differs.

As illustrated in Figure 5 in particular, the internal stiffeners 35, 36, 37 comprise a first group of stiffener 35, a second group of stiffener 36 and a third group of stiffener 37. The first group of stiffener 35 forms a first stiffener frame 35 all around the orifice 31 and inside the external stiffener frame 33. The first stiffener frame 35 is welded to the external stiffener frame 33 by extending the stiffeners 35 to attach to the external stiffeners 33. The second group of stiffener 36 forms also a second stiffener frame 36 all around the orifice 31 and inside the first stiffener frame 35. In the same way as the first frame 35, the second stiffener frame 36 is welded to the first stiffener frame 35 by extending the stiffeners 36.

Finally, the third group of stiffeners 37 comprises two junction stiffeners 37. The junction stiffeners 37 are on the one hand welded to the rigid container 12 of the sump structure 9 and on the other hand welded to the second stiffener frame 36. junction stiffeners 37 are located on either side of the rigid container 12. In the same way as for the internal stiffeners 34 of the figure 2 , the junction stiffeners 37 can advantageously have an increasing thickness of the rigid container 12 towards the second stiffener frame 36 in order to best absorb the forces exerted around the orifice 31 of the metal plate 30 and transfer them homogeneously from the rigid container 12 to the external stiffeners 33 passing through the different groups of internal stiffeners 35, 36, 37.

The sump structure 9 comprises a sump bottom 38 to which two sump stiffeners 39 are welded. The sump stiffeners 39 are welded to an external surface of the sump bottom 38. The sump stiffeners 39 are arranged in a plane orthogonal to the external surface of the sump bottom 38. In the embodiment shown on the figure 5 , the sump stiffeners 39 intersect in the center of the sump bottom 38 and are oriented relative to each other at 90°. In addition, each sump stiffener 39 is oriented at 45° relative to the junction stiffeners 37.

In reference to the Figure 6 , a cutaway view of an LNG ship 70 shows a watertight and insulated tank 71 of generally prismatic shape mounted in the double hull 72 of the ship. The double hull 72 comprises an internal shell 1 and an external shell 2. The wall of the tank 71 comprises a primary waterproof barrier intended to be in contact with the LNG contained in the tank, 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 primary waterproof barrier and the secondary waterproof barrier and between the secondary waterproof barrier and the double hull 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 appropriate connectors, to a maritime or port terminal to transfer a cargo of LNG from or to the tank 71.

There Figure 6 represents an example of a maritime terminal comprising a loading and unloading station 75, an underwater pipeline 76 and an onshore installation 77. The loading and unloading station 75 is a fixed off-shore installation comprising a movable arm 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 connect to the loading/unloading pipes 73. The adjustable mobile arm 74 adapts to all LNG carrier templates. A connection pipe not shown extends inside the tower 78. The loading and unloading station 75 allows the loading and unloading of the LNG tanker 70 from or to the onshore installation 77. This includes 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 onshore installation 77 over a long distance, for example 5 km, which makes it possible to keep the LNG ship 70 at a long distance from the coast during loading and unloading operations.

To generate the pressure necessary for the transfer of the liquefied gas, pumps on board the ship 70 and/or pumps fitted to the on-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 and that it includes all the means described as well as their combinations if these fall within the scope of the invention. scope of the invention as described in the claims.

The use of the verb “include”, “understand” or “include” and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

In the claims, any parenthetical reference sign shall not be construed as a limitation of the claim.

Claims (20)

1. Ship (70) including a metal inner hull (1) having an internal surface and an external surface, an outer hull (2) disposed outside the inner hull (1) facing the external surface, and at least one tank (71) disposed in the inner hull (1) and supported against the internal surface of the inner hull (1), the tank including at least one tank wall (4), the inner hull (1) including a plurality of hull plates (16) welded to one another,

   the ship (70) including at least one traversing element (9, 20) passing through an opening (3) produced in the inner hull (1) and in the wall (4) of the tank, at least one hull plate (16) bordering said opening (3);

   in which the ship (70) includes at least one metal plate (30) including at least one orifice (31) through which the traversing element (9, 20) passes, the metal plate (30) having a thickness greater than the thickness of said at least one hull plate (16) bordering the opening (3), the metal plate (30) being welded to said at least one hull plate (16) bordering the opening (3), the metal plate (30) extending around the opening (3).
2. Ship (70) according to Claim 1, in which the thickness of the metal plate (30) is greater than or equal to 1.2 times the thickness of the at least one hull plate (16) bordering the opening (3).
3. Ship (70) according to Claim 1 or Claim 2, in which the metal plate (30) is made of stainless steel and the hull plates (16) are made of carbon steel.
4. Ship (70) according to any one of Claims 1 to 3, in which the orifice (31) is circular and the traversing element (9, 20) has a circular section.
5. Ship (70) according to any one of Claims 1 to 4, in which the ship (70)

   includes a first array of stiffeners (32) welded to an external surface of the metal plate (30) and a second array of stiffeners (17) welded to the external surface of the inner hull (1); and

   in which the first array of stiffeners (32) includes internal stiffeners (34, 35, 36, 37) and external stiffeners (33), the external stiffeners (33) being arranged so as to form a stiffener frame all around the internal stiffeners (34, 35, 36, 37), stiffeners of the second array of stiffeners (17) being welded to the external stiffeners (33).
6. Ship (70) according to Claim 5, in which the stiffeners of the first array of stiffeners (32) are made of stainless steel and the stiffeners of the second array of stiffeners (17) are made of carbon steel.
7. Ship (70) according to Claim 5 or Claim 6, in which the internal stiffeners (34, 35, 36, 37) are regularly distributed all around the traversing element (9, 20).
8. Ship according to Claim 5 or Claim 6, in which the internal stiffeners (34, 35, 36, 37) are irregularly distributed all around the traversing element (9, 20).
9. Ship (70) according to any one of Claims 5 to 8, in which the second array of stiffeners (17) includes primary stiffeners (18) and secondary stiffeners (19), each primary stiffener (18) being formed essentially in a plane orthogonal to the external surface of the inner hull (1) and being welded on the one hand to the inner hull (1) and on the other hand to the outer hull (2), and each secondary stiffener (19) being formed essentially in a plane orthogonal to the external surface of the inner hull (1) and being welded to the inner hull (1) and disposed at a distance from the outer hull (2).
10. Ship (70) according to any one of Claims 5 to 9, in which the internal stiffeners (34) are welded on the one hand to the metal plate (30) and on the other hand to the external stiffeners (33).
11. Ship (70) according to any one of Claims 5 to 10, in which the internal stiffeners (34) are made in gusset plate form and have a thickness increasing from the traversing element (20) toward the external stiffeners (33).
12. Ship (70) according to any one of Claims 5 to 11, in which the first array of stiffeners (32) includes at least three internal stiffeners (34) regularly distributed all around the orifice (31).
13. Ship (70) according to any one of Claims 5 to 12, in which each internal stiffener (34) is fixed to a portion of an external stiffener (33), a stiffener of the second array of stiffeners (17) being fixed to the same said portion of external stiffener (33).
14. Ship (70) according to any one of Claims 1 to 13, in which the tank wall (4) is a ceiling wall of the tank and the traversing element is a pipe (20).
15. Ship (70) according to Claim 14, in which the ceiling wall (4) includes a thermally insulating barrier (8) supported by the inner hull (1) and a sealing membrane (7) supported by the thermally insulating barrier (8), the thermally insulating barrier (8) and the sealing membrane (7) being interrupted at a distance from the pipe (20), the sealing membrane being fixed to the metal plate (30) by means of a connecting ring all around the pipe (20), the connecting ring including a portion projecting from the external surface of the metal plate (30) so as to form a circular stiffener (21).
16. Ship (70) according to Claim 15 prise in combination with any one of Claims 5 to 13, in which at least one end of the internal stiffeners (34) is welded to the circular stiffener (21).
17. Ship (70) according to any one of Claims 1 to 13, in which the tank wall (4) is a bottom wall of the tank and the traversing element is a sump structure (9).
18. Ship (70) according to any one of Claims 1 to 17, in which the tank (71) is a sealed and internally insulating membrane tank intended for the storage of a liquefied gas.
19. Transfer system for a cold liquid product, the system including a ship (70) according to any one of Claims 1 to 18, insulated pipes (73, 79, 76, 81) arranged in such a manner as to connect the tank (71) installed in the inner hull (1) of the ship (70) to a floating or terrestrial storage installation (77) and a pump for driving a flow of cold liquid product through the insulated pipes from or to the floating or terrestrial storage installation to or form the tank of the ship (70).
20. Method for loading or offloading a ship (70) according to any one of Claims 1 to 18, in which a cold liquid product is routed through insulated pipes (73, 79, 76, 81) from or to a floating or terrestrial storage installation (77) to or from the tank (71) of the ship.

Images