EP3938698A2

EP3938698A2 - Vessel wall comprising improved insulation around a bushing

Info

Publication number: EP3938698A2
Application number: EP20725887.2A
Authority: EP
Inventors: Amaury Mange; Romain DENOIX
Original assignee: Gaztransport et Technigaz SA
Current assignee: Gaztransport et Technigaz SA
Priority date: 2019-03-15
Filing date: 2020-03-12
Publication date: 2022-01-19
Also published as: SG11202109793VA; CN113748292B; FR3093786B1; FR3093786A1; CN113748292A; KR20210134978A; WO2020188195A2; WO2020188195A3

Abstract

The present invention relates to a vessel wall comprising a primary insulation layer (224) extending mainly in a primary plane (P1) and a secondary insulation layer (226) extending mainly in a secondary plane (P2). The vessel wall (22) comprises a bushing (3) which is provided in an upper wall of the vessel (22b) and around which a peripheral area (229) extends in the secondary plane (P2) of the secondary insulation layer (226).

Description

Title: Tank wall including improved insulation around a crossing

The field of the present invention is that of transport tanks with corrugated sealed membranes, for the storage and / or transport of a liquid, and in particular sealed and thermally insulating tanks for transporting a gas in the liquid state.

The invention relates to the field of sealed and thermally insulating tanks for the storage and / or transport of liquid at low temperature, such as tanks for the transport of Liquefied Petroleum Gas (LPG), for example having a temperature between -50 ° C and 0 ° C, or for the transport of Liquefied Natural Gas (LNG), at approximately -162 ° C and 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.

Usually, the tanks used for the storage of liquid at low temperature comprise several passages for the passage of the pipes which can be intended for example for the loading or the unloading of the liquid, or else for the capture of gases in the tank head. All of these pipes are surrounded by a coaming, that is, a vertical structural element that frames the pipes.

In certain situations where the number of pipes or their dimensions are limited, the use of a coaming can be avoided. It is nevertheless necessary to provide openings which allow the pipes to pass through the wall of the tank.

These openings are however not suitable for the passage of the

unloading of the cargo present in the tank, the latter involving making an opening in the wall of the tank of significant size.

The size of this opening thus generates difficulties at the level of the secondary insulation layer of the tank, because there are significant temperature differences between the secondary insulation layer and the element arranged in the opening and which passes through the wall.

The object of the present invention is to respond to the drawbacks mentioned above by eliminating the coaming, by grouping several pipes of the tank in a single passage and by managing the temperature differences between the passage and the secondary insulation layer.

The subject of the invention is therefore a wall of a tank capable of containing liquid cargo and intended to be installed in a transport vessel, the wall comprising at least one primary insulation layer extending mainly in a primary plane and a secondary insulation layer extending mainly in a secondary plane, the primary insulation layer and the secondary insulation layer being superimposed in a direction transverse to the insulation planes of the layers, the tank wall comprising at least one bushing taking the form of a hollow cylinder passing through the layers as well as a pipe extending into the bushing, characterized in that the primary insulation layer comprises a peripheral zone which extends around the bushing and into the secondary plane of the secondary insulation layer.

It is understood here that part of the primary insulation layer rises along the crossing and crosses the general extension plane of the secondary insulation layer, such a part being defined by the peripheral zone.

According to the invention, the vessel may contain liquefied gas, in particular liquid natural gas, liquefied petroleum gas and generally any liquefied hydrocarbon. The transport vessel can then include several tanks, able to store and transport gas in the liquid state.

The primary insulation layer and the secondary insulation layer are sets of parts for thermally insulating the tank, and they may have different thicknesses. The primary plane and the secondary plane are then defined as the planes passing respectively through the middle of the thickness of the primary insulation layer and through the middle of the thickness of the secondary insulation layer. The crossing has a cylindrical shape, in particular circular. The passage takes the form of a duct of circular section which passes right through the wall of the tank which is the subject of the invention. The passage then makes it possible to pass a pipe, the latter possibly being a pipe for unloading the liquid cargo or a pipe for discharging the gas phase of the liquid cargo. In order to discharge the maximum of the liquid cargo, the discharge pipe extends from the outside of the tank to the immediate vicinity of a bottom of the tank. The evacuation tube extends from the outside of the tank to the tank top. The bushing according to the invention can of course comprise an unloading tube and at least one evacuation tube.

According to the invention, the peripheral zone is in communication with the portion of the primary insulation layer extending in the primary plane, so that they form one and the same volume. This feature makes it possible to sweep with one and the same inert gas the portion of the primary insulation layer which is located in the primary plane and the part of this primary insulation layer which extends in the secondary plane.

According to one characteristic of the invention, the peripheral zone accommodates at least one peripheral part which extends in the secondary plane of the secondary insulation layer over a radius of between 400mm and 1000mm around an axis through which the bushing passes. . It is then understood that the portion of the primary insulation layer located in the primary plane and the peripheral part are swept by the same flow of inert gas.

The room or zone is peripheral in the sense that it surrounds the crossing. It can be an annular or polygonal part or area. Although constituting the primary insulation layer, the peripheral part is separated from the insulation panels of the primary insulation layer and which extend in the primary plane.

According to one characteristic of the invention, a thickness of the peripheral zone is identical to a thickness of the secondary insulation layer. This characteristic guarantees the absence of coaming around the crossing. The thicknesses are measured along a line parallel to an axis of revolution of the feed-through and the thickness of the part device is also identical or substantially identical to the thickness of the secondary insulation layer, except for manufacturing and assembly tolerances.

According to one characteristic of the invention, a partition extends at least around the passage, between the secondary insulation layer and the peripheral zone. Such a partition separates an internal volume of the secondary insulation layer from an internal volume of the peripheral zone which is part of the primary insulation layer. The partition may be cylindrical and may be formed of an assembly consisting of a circular ring and an insulating material which may for example be glass wool.

According to one characteristic of the invention, the partition provides a seal between the primary insulation layer and the secondary insulation layer. This partition therefore separates the volume of the primary insulation layer from the volume of the secondary insulation layer, in the vicinity of the peripheral zone.

According to a characteristic of the invention, at least one gas discharge tube extends into the passage and has an outer end which opens out outside the vessel and an internal end which opens into a head of the vessel. The tank top includes the gases resulting from the evaporation of the liquid cargo and is therefore close to the top wall of the tank. The gas evacuation tube then makes it possible to suck the gases present in the tank top so as to supply a thermal machine which equips the transport vessel or to adapt the pressure in the tank top.

According to another aspect, the pipe is a pipe for unloading the liquid cargo, comprising in particular a first end which opens out of the internal volume of the tank and a second end which opens into the tank, in the vicinity of a bottom wall of the tank. tank.

The invention also covers a wall which has several feedthroughs as described above.

The invention also covers a transport vessel, for example an LNG carrier, comprising at least one vessel wall which has the above characteristics. According to one characteristic of the transport vessel, the latter comprises at least one bridge of the transport vessel, one edge of the bridge being at a non-zero distance from the crossing.

The deck of the transport vessel extends at a non-zero distance from the crossing in order to allow movements which result from thermal expansions between the crossing, which may be in contact with the cargo in the liquid state, and the bridge which is isolated from this cargo by at least the primary insulation layer and the secondary insulation layer.

According to one aspect, the non-zero distance which separates the crossing from the edge of the bridge is filled by a thermally insulating part.

According to one characteristic of the transport vessel, the edge of the bridge extends at least partially axially to the right of the peripheral zone along a straight line parallel to the crossing axis.

According to one characteristic of the transport vessel, a cylinder arranged around the crossing is supported by an external face of the bridge and defines with the crossing a space containing a thermally insulating material, the space being closed by a plate. The cylinder insulation can be made, for example, of glass wool, expanded foam or perlite. It is then understood that the cylinder reinforces the insulation around the bushing and that the plate allows to hermetically seal the space of the cylinder.

According to one characteristic of the transport vessel, the edge of the deck is radially disposed between the crossing and an internal face of the cylinder. Such an organization makes it possible to use the bridge so that it takes up the axial forces which come from the pressure inside the vessel around the crossing and which the primary insulation layer is subjected to.

Still according to a characteristic of the transport vessel, a pipe passes through the cylinder, the peripheral zone and opens into the primary insulation layer, the pipe being configured to be connected to an inert gas supply device. A first pipe opening, a second pipe opening and a third pipe opening are formed at least respectively in the cylinder, in the deck of the transport vessel and through the peripheral part, in order to to allow the passage of the pipe through a cylinder insulation and the primary insulation layer. Preferably, the inert gas is nitrogen.

The invention also covers a transport vessel comprising a wall of a tank capable of containing liquid cargo and intended to be installed in a transport vessel, the wall comprising at least one primary insulation layer extending mainly in a primary plane and a secondary insulation layer extending predominantly in a secondary plane, the primary insulation layer and the secondary insulation layer being superimposed in a direction transverse to the insulation planes of the layers, the tank wall comprising at least one crossing in the form of a hollow cylinder passing through the layers as well as a pipe extending into the crossing, the transport vessel including at least one deck of the transport vessel, one edge of the bridge being spaced apart non-zero crossing, the edge of the bridge is radially disposed between the crossing and an internal face of a cylinder arranged around the crossing and supported by an external face of the bridge.

According to one aspect of the transport vessel, the edge of the bridge extends at least partially axially to the right of the peripheral zone in a straight line parallel to the crossing axis.

The invention also relates to a method for loading or unloading liquid natural gas from a vessel comprising a wall according to the preceding characteristics or from a liquid natural gas transport vessel according to one of the preceding characteristics.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description given below by way of indication in relation to the drawings in which:

[Fig. 1] is a side view of a transport vessel showing at least one tank for transporting liquid cargo as well as a passageway entering the tank;

[Fig. 2] is a sectional view, in a vertical direction of the tank, of an upper wall of the tank in which the passage is formed; [Fig. 3] is a close-up view in section along the vertical direction of the vessel of the peripheral zone of penetration of the bushing into the upper wall of the vessel in FIG. 2.

It should first be noted that the figures set out the invention in detail to implement the invention, said figures can of course serve to better define the invention, if necessary.

In Figure 1 is shown a transport vessel 1, for example an LNG carrier, which comprises four tanks 2 for the transport or storage of liquefied natural gas. At least one of the tanks 2 comprises a tank wall 22 which defines an internal cavity 20 in which the liquefied gas is stored. The vessel wall 22 comprises a vessel bottom wall 22a, an upper vessel wall 22b, opposite the vessel bottom wall 22a in a vertical direction V of the vessel 2, and side walls 22c which extend between the vessel bottom wall 22a and the vessel top wall 22b.

Figure 2 illustrates a sectional view of the tank 2 and of the passage 3 formed in the upper wall of the tank 22b, in the vertical direction V of the tank illustrated in Figure 1. This passage 3 takes the form of a hollow cylinder, a first end of which is located in an external environment of the tank 2 while the other end is arranged in a cap 21 of tank 2 corresponding to a part of the internal cavity 20 close to the upper wall 22b of the wall of tank 22, that is to say a portion of tank 2 where gas in the liquid state is not present in normal conditions of use.

The feed-through 3 extends around and along an axis of revolution, called the feed-through axis R and comprises a feed-through wall which extends peripherally around the feed-through axis R of the feed-through 3 and which defines a passage through the upper wall of the tank 22b. The passage 3 then allows the passage of at least one pipe 31, in particular a pipe for unloading the liquefied gas and / or a gas discharge pipe 32. The passage 3 also comprises a cover 33 covering the pipe. part outside the tank 2 and allowing the passage 3 to be sealed off once the pipe 31 and / or the gas discharge pipe 32 have been installed. The pipe 31, in the case of a pipe for discharging gas in the liquid state, extends in the liquid portion of the cargo to the immediate vicinity of the bottom wall of the vessel 22a, to discharge the maximum amount of liquefied gas outside the tank 2. The gas discharge tube 32 extends from the outside of the tank to the inside of the tank 2, and opens into the part of the tank 2 called the top 21 of tank 2, where the natural gas is in the gaseous state. The top 21 of tank 2 is a space near the top wall of tank 22b which contains a gas phase of the liquid cargo which results from its

evaporation. The gas evacuation tube 32 then makes it possible to suck the gaseous phase of the liquid cargo to supply a thermal machine (not shown) which equips the transport vessel, or to allow the pressure in the sky 21 to be adapted from tank 2.

The upper tank wall 22b is composed of a superposition of an insulating and waterproof layer, in order to thermally insulate the internal cavity 20 and to ensure its tightness. The upper wall of the tank 22b then comprises, respectively from the internal cavity 20 towards an environment outside the tank 2, at least one primary insulation layer 224 and a secondary insulation layer 226. The other walls of the tank can also comprising such primary insulation layer 224 and secondary insulation layer 226.

The primary insulation layer 224 consists of a primary membrane 222, made up of a plurality of plates welded together and comprising waves 2221, and a plurality of primary insulation panels 221. The primary membrane 222 constitutes a face in direct contact with the liquefied gas contained in the internal cavity 20.

The secondary insulation layer 226 consists of several secondary insulation panels 220 and a secondary membrane 225, facing the primary insulation layer 224. The secondary insulation layer 226 of the upper wall of the tank 22b is then surmounted by a bridge 228 in contact with the outside of the tank 2.

According to one characteristic of the invention, the primary insulation layer 224 defines a volume which is swept by an inert gas, and is delimited on one side by the membrane primary 222 and on the other hand by the secondary membrane 225. Equivalently, the secondary insulation layer 226 defines a volume, distinct from the volume of the primary insulation layer 224, which is swept by an inert gas, and which is delimited on one side by the secondary membrane 225 and on the other side by the bridge 228.

The circulation of inert gas in the primary insulation layer 224 and in the secondary insulation layer 226 allows for example the detection of leaks of the cargo outside the internal cavity 20 of the tank 2. The leak detection occurs. then performs separately for the primary insulation layer 224 and for the secondary insulation layer 226. Advantageously, the inert gas used is nitrogen.

The upper vessel wall 22b also comprises a cylinder 233 extending radially around the bushing 3. This cylinder 233 has an axis of revolution which coincides with the bushing axis R.

FIG. 3 shows a close-up view in section along the vertical direction V of the vessel, of the passage 3 and of its peripheral zone. In the following description, “superposition” is understood to mean a superposition in the vertical direction V of the tank, going from the internal cavity 20 of the tank to the outside of the tank.

The passage 3 defines a passage in the upper wall of the vessel 22b for the pipe 31, in particular the pipe for unloading the liquid cargo, and / or for the gas discharge pipe 32, for the suction of gases from the air 21 tank.

The top wall of the vessel 22b comprises the primary insulation layer 224 consisting in part of the primary membrane 222 on which the primary insulation panel 221 is superimposed. The primary membrane 222 is in contact with the liquefied gas stored in the internal cavity. 20 of the tank. The primary membrane 222 is composed of a plurality of plates comprising waves 2221 distributed over its surface and it surrounds the passage 3, nevertheless remaining at a non-zero distance from this passage 3. Such a configuration of the primary membrane 222 gives it provides greater resistance to the stresses generated on the tank, in particular to thermal shrinkage during the cooling of the tank, the hydrostatic pressure due to the loading of the liquid cargo, as well as the dynamic pressure due to the movement of the cargo, especially in because of the swell. The waves 2221 on the primary membrane 222 then allow it to deform to overcome these stresses. The primary membrane 222 is

preferably stainless steel.

A bracket 236 is placed in the internal cavity 20 of the tank, so that it is in contact with the primary membrane 222 and with the bushing 3. Only the ends of the bracket 236 are welded respectively to the primary membrane 222. and to the feed-through 3. Such a configuration of the bracket 236 allows it both to close the space between the primary membrane 222 and the feed-through 3, and also to give flexibility in this area to absorb the dynamic stresses of the. tank. Indeed, the crossing 3 can cut several waves 2221 so that it is necessary to restore flexibility in the passage area of the crossing 3. This flexibility is for example given by the fact that the square 236 is welded only. at its ends.

The primary insulation panel 221 is made of an insulating material and contributes to the thermal insulation of the tank, necessary for the storage of liquid natural gas at low temperature (-163 ° Celsius).

The primary insulation layer 224 is defined by a thickness Tl measured along a line parallel to the traverse axis R and this thickness extends from the primary membrane to the secondary membrane. The primary insulation layer 224 extends around the bushing 3 to a non-zero distance DI, in order to adapt to the expansion and shrinkage of the bushing 3 caused by temperature variations during loading or unloading of the tank. The primary insulation layer 224 has the function of forming a first thermal insulation barrier of the tank.

A primary plate 223 extends between the primary membrane 222 and the primary insulation panel 221. The primary plate 223 is a wood plywood which may include stainless steel strips (not shown) allowing the edges of the plates to be welded. primary membrane 222.

The secondary insulation layer 226 comprises the secondary membrane 225, otherwise called triplex, superimposed on the primary insulation layer 224 and which extends in the vicinity of the passage 3, up to a distance D2 which is not zero and strictly greater than the DI distance mentioned above. The secondary membrane 225 is a material comprising three layers, namely two outer layers of fiberglass fabrics and an intermediate layer of thin metal foil, for example an aluminum foil with a thickness of about 0.1 mm. The secondary membrane 225 has flexibility in bending, allowing it to follow the deformations of the tank due to the deformation of the shell by the swell or by the cooling of the tank. By flexural flexibility is meant the ability of the material to be bent to form curves without breaking.

The secondary insulation panel 220 is superimposed on the secondary membrane 225.

The secondary insulation panel 220 is made of a thermally insulating material and participates together with the primary insulation panel 221 in the thermal insulation of the tank. The secondary insulation layer 226 is then defined by a thickness T2 measured along a straight line parallel to the crossing axis R between the secondary membrane and a secondary plate 227 glued against the bridge.

The secondary insulation layer 226 extends around the passage 3 up to the non-zero distance D2, this distance D2 being strictly greater than the distance referenced Dl. The secondary insulation layer 226 comprises a first face 2261, facing the bridge 228 and a second face 2262, facing the secondary membrane 225.

A secondary plate 227 extends between the bridge 228 and the secondary insulation panel 220. The secondary plate 227 stiffens the secondary insulation panel 220 and may in particular be made of wood plywood.

According to one aspect of the invention, a peripheral part 240 extends in a peripheral zone 229, which is defined as the zone which extends in the insulation plane P2 of the secondary insulation layer 226 and radially between the secondary insulation layer 226 and the bushing 3, at least over a radial distance equivalent to the distance D2 mentioned above. The peripheral part 240 has a thickness T3 measured along a straight line parallel to the feed-through axis R which is the same or similar to the thickness T2 of the secondary insulation layer 226, with manufacturing and / or manufacturing tolerances. fitting close. This thickness T3 also defines the part of the layer of primary insulation 224 which extends around the passage 3 and which is in the secondary plane P2 of the secondary insulation layer 226. In the present description, this part is the peripheral zone 229.

The peripheral part 240 is a part participating in the thermal insulation of the tank and may be made of materials identical to the insulating panels of the primary insulation layer 224. The peripheral part 240 is housed in the peripheral zone 229.

According to the invention, the peripheral part 240 is in communication with the volume of the primary insulation layer 224 at least by virtue of a passage space 242 defined by the distance DI between the primary insulation layer 224, the peripheral part 240 , and the feedthrough 3. This feedthrough space 242 can be filled with a feedthrough thermal insulator 241, preferably glass wool which allows, by virtue of its flexibility, to take up the cold effects of the feedthrough 3, while allowing circulation of inert gas. It is then understood that the peripheral zone 229 is swept by the inert gas circulating in the volume of the primary insulation layer 224. This characteristic is considered to be that the peripheral part 240 forms part of the primary insulation layer 224.

The secondary insulation layer 226 thus comprises a counterbore which surrounds the passage 3, this counterbore being formed by the peripheral zone 229 and filled in by the peripheral part 240.

Preferably and in a non-limiting manner, the peripheral part 240 extends in the secondary plane P2 of the secondary insulation layer 226 over a radius of between 400mm and 1000mm around the axis of passage R of the passage 3.

A first annular plate 2291 extends between the peripheral part 240 and the bridge 228. A second annular plate 2292 may be disposed between the primary insulation panel 221 and the peripheral part 240. The first annular plate 2291 and the second annular plate 2292 can be, without limitation, made of densified wood or of polyurethane and their function is to stiffen the peripheral part 240. Finally, the upper wall of the tank 22b comprises the bridge 228 of the transport vessel which covers the secondary plate 227 and which extends at least partially axially in line with the peripheral part 240, that is to say along a line parallel to the traverse axis R.

The bridge 228 therefore at least partially covers the first annular plate 2291. In addition, the bridge 228 extends to a non-zero distance from the crossing 3 and comprises an edge 2280 disposed radially between the crossing 3 and an internal face. 2334 of the cylinder 233. The edge 2280 thus delimits a passage 2332 between the bridge 228 and the passage 3. Such a configuration of the bridge 228 makes it possible to authorize the thermal expansions due to loading or unloading of the liquid cargo. The passage 2332 can be filled with a thermal insulator, the latter then being disposed between the edge 2280 and the passage 3.

The bridge 228 comprises an outer face 2281, facing the exterior environment of the tank, and an inner face 2282, facing the secondary plate 227 and the first annular plate 2291. An adhesive 230 can be positioned between the face. internal 2282 of the bridge 228, the first annular plate 2291 and the secondary plate 227. The adhesive 230 may for example be in the form of spots of adhesive and enables the first annular plate 2291 and the secondary plate 227 to be secured to the bridge 228.

A partition 232 extends parallel to the crossing axis R, radially at least between the peripheral part 240 and the secondary insulation layer 226. The partition 232 emerges perpendicularly from the interior face 2282 of the deck 228 until it is at contact of the secondary membrane 225. The partition 232 is composed of a ring 2321 and an insulating material 2322, for example glass wool. According to the invention, the ring 2321 of the partition 232 has a profile of a right circular cylinder. It is then understood that the partition 232 has the function of thermally insulating and sealingly separating the peripheral part 240 from the secondary insulating layer 226, so that the inert gas circulating respectively in each of the volumes does not mix. According to this characteristic, the junction between the ring 2321 and the secondary membrane 225 may for example be the subject of welding in order to make this junction waterproof. So In general, it is considered that the partition 232 separates the volume of the secondary layer 226 from the volume of the peripheral zone 229.

The upper wall of the vessel 22b comprises the cylinder 233 positioned resting on the outer face 2281 of the bridge 228. The cylinder 233 extends radially around the passage 3 and axially in line with the peripheral part 240. The cylinder 233 comprises a space 2331 fills with a thermally insulating material called cylinder insulating layer 242 and which can be for example glass wool, expanded foam or perlite. The function of the cylinder 233 is to increase the thermal insulation around the passage 3. The space 2331 of the cylinder 233 is delimited by the passage 3, the cylinder 233, a part of the bridge 228 with its edge 2280 and a circular plate 234. The circular plate 234 overlaps the space 2331, opposite the bridge 228 and extends perpendicular to the crossing axis R and from the crossing 3 to the cylinder 233. The space 2331 of the cylinder 233 is therefore

communicating with the volume of the primary insulation layer 224 and the volume occupied by the peripheral part 240, by means of the passage 2332 formed between the edge 2280 of the bridge 228 and the crossing 3.

It is understood from the previous characteristic that the primary insulation layer 224, the peripheral part 240 and the cylinder insulating layer 242 communicate and form a single volume, swept by the same flow of inert gas.

A pipe 235, taking the form of a tube, partly extends into the primary insulation layer 224. To this end, several openings are formed in the upper wall of the tank 22b, including a first pipe opening 2351 formed. through the cylinder 233, a second pipe opening 2352 formed through the bridge 228, close to its edge 2280, and a third pipe opening 2353 formed through the second annular plate 2292. It is then understood that the pipe 235 circulates from the outside of the tank to the primary insulation layer 224, in particular via the cylinder insulating layer 242 and the peripheral part 240, by means of the pipe openings 2351, 2352, 2353 mentioned above. The pipe 235 is configured to be connected to an inert gas supply device (not shown) and its function is to participate in a gas sweep of the primary insulation layer 224. The injection of inert gas into the layer d The primary insulation 224 makes it possible, by means of an external analysis device (not shown), to verify the absence of invasion of the primary insulation layer 224. The same applies to the secondary insulation layer 226 which is also connected to an inert gas supply device and to an external analysis device verifying the flooding of the secondary insulation layer 226.

The invention thus achieves the object that it had set itself by eliminating the coaming and by grouping together several pipes of the tank in the same passage, while improving the thermal insulation and the tightness of this passage, by means of the peripheral zone and of the cylinder extending radially around the bushing.

The invention cannot however be limited to the means and configurations exclusively described and illustrated, and also applies to all equivalent means or configurations and to any combination of such means or configurations. In particular, it goes without saying that it applies to any shape and / or dimension of crossing.

Claims

1. Wall (22) of a tank (2) suitable for containing liquid cargo and intended to be installed in a transport vessel (1), the wall (22) comprising at least one primary insulation layer (224) extending mainly in a primary plane (PI) and a secondary insulation layer (226) extending mainly in a secondary plane (P2), the primary insulation layer (224) and the secondary insulation layer ( 226) being superimposed in a direction transverse to the insulation planes (PI, P2) of the layers (224, 226), the tank wall (22) comprising at least one passage (3) in the form of a hollow cylinder passing through the layers (224, 226) as well as a pipe (31) which extends in the passage (3), characterized in that the primary insulation layer (224) comprises a peripheral zone (229) which extends around the passage (3) and in the secondary plane (P2) of the secondary insulation layer (226).

2. Wall (22) of a tank (2) according to the preceding claim, wherein the peripheral zone (229) accommodates at least one peripheral part (240) which extends in the secondary plane (P2) of the layer of 'secondary insulation (226) over a radius of between 400mm and 1000mm around a bushing axis (R) of the bushing (3).

3. Wall (22) of a tank (2) according to any one of the preceding claims, in which a thickness (T3) of the peripheral zone (229) is identical to a thickness (T2) of the insulation layer. secondary (226).

4. Wall (22) of a tank (2) according to any one of the preceding claims, in which a partition (232) extends at least around the passage (3) between the secondary insulation layer (226 ) and the peripheral zone (229).

5. Wall (22) of the tank (2) according to the preceding claim, wherein the partition (232) provides a seal between the primary insulation layer (224) and the secondary insulation layer (226).

6. Wall (22) of the tank (2) according to any one of the preceding claims, in which at least one discharge tube (32) of the gases extends into the passage (3) and has an outer end (322) which opens outside the tank (2) and an internal end (321) which opens into a ceiling (21) of the tank (2).

7. A vessel wall (22) (2) according to any preceding claim, wherein the pipe (31) is a liquid cargo discharge pipe.

8. Transport vessel (1) comprising at least one wall (22) of the tank (2) according to any one of the preceding claims.

9. Transport vessel (1) according to the preceding claim, comprising at least one bridge (228) of the transport vessel (1), one edge (2280) of the bridge (228) being at a non-zero distance from the crossing (3). ).

10. Transport vessel (1) according to the preceding claim, wherein the edge (2280) of the bridge (228) extends at least partially axially to the right of the peripheral zone (229) along a straight line parallel to the axis. crossing (R).

11. Transport vessel (1) according to claim 9 or 10, wherein a cylinder (233) disposed around the crossing (3) is supported by an outer face (2281) of the bridge (228) and delimits with the crossing ( 3) a space (2331) containing a thermally insulating material, the space (2331) being closed by a plate (234).

12. Transport vessel (1) according to the preceding claim, wherein the edge (2280) of the bridge (228) is radially disposed between the crossing (3) and an internal face (2334) of the cylinder (233).

13. Transport vessel (1) according to any one of claims 10, wherein a pipe (235) passes through the cylinder (233), the peripheral zone (229) and opens into the primary insulation layer (224), the pipe (235) being configured to be connected to an inert gas supply device.

14. Transport vessel (1) comprising a wall (22) of a tank (2) capable of containing liquid cargo and intended to be installed in a transport vessel (1), the wall (22) comprising at least one primary insulation layer (224) extending predominantly in a primary plane (PI) and a secondary insulation layer (226) extending predominantly in a secondary plane (P2), the primary insulation layer (224) and the secondary insulation layer (226) being superimposed in a direction transverse to the insulation planes (PI, P2) of the layers (224, 226), the tank wall (22) comprising at least one passage ( 3) taking the form of a hollow cylinder crossing the layers (224, 226) as well as a pipe (31) which extends into the passage (3), the transport vessel (1) comprising at least one bridge ( 228) of the transport vessel (1), an edge (2280) of the bridge (228) being at a non-zero distance from the crossing (3), the edge (2280) of the bridge (228) is radially disposed between the crossing ( 3) and an internal face (2334) of a cylinder (233) arranged around the bushing (3) and supported by an external face (2281) of the bridge (228).

15. A method of loading or unloading a liquid natural gas from a vessel (2) comprising a wall (22) according to claims 1 to 7 or from a transport vessel (1) for liquid natural gas according to claims. 8 to 12.