WO2021186133A1

WO2021186133A1 - Perforation means for a tank of natural gas in the liquid state

Info

Publication number: WO2021186133A1
Application number: PCT/FR2021/050444
Authority: WO
Inventors: Bertrand BUGNICOURT; Emmanuel HIVERT; Aissata SOW; Sylvestre PELTIER; Laurent Spittael; Nicolas Dupont; Alexandre DIVOT; Bruno SORREGUIETA-ADER
Original assignee: Gaztransport Et Technigaz
Priority date: 2020-03-18
Filing date: 2021-03-18
Publication date: 2021-09-23
Also published as: KR20210124231A; WO2021186133A4; CN115836177A; KR20230143628A; FR3108384A1; KR102586601B1; FR3108384B1; KR102654638B1

Abstract

The invention primarily relates to a perforating device (32) for a sealed, thermally insulating tank (2) designed to contain a fluid, characterised in that said perforating device (32) comprises an actuation means (34) and a perforating member (36) for the tank (2), the actuation means (34) being designed to produce a movement of the perforating member (36).

Description

DESCRIPTION

Title: Means of perforating a natural gas tank in the liquid state

The present invention relates to the field of natural gas tanks in the liquid state in maritime transport. More particularly, the invention refers to the devices prior to the repair of such tanks used in the event of a leak of natural gas in the liquid state from such a tank.

Natural gas in the liquid state, or liquid natural gas, is transported by sea in sealed and thermally insulating storage tanks on transport ships. Natural gas is kept in liquid form to increase the amount of liquid natural gas transported per tank, the volume of one liter of natural gas in liquid form being much less than the volume of one liter of natural gas in gaseous form. These tanks maintain the liquid natural gas at very low temperature, and more precisely at a temperature below -163 ° C, temperature at which the natural gas is in liquid form at atmospheric pressure.

Such liquid natural gas tanks can also be used as a fuel tank by some ships. In other words, ships load and store liquid natural gas in their tanks and then use the liquid natural gas as fuel for the ship's engine (s).

In addition, these tanks can be used for the terrestrial storage of liquid natural gas such as for example to recover the liquid natural gas on the docks during the unloading of the liquid natural gas transported by tanks arranged on the ships.

Liquid natural gas tanks generally have a parallelepipedal shape, the walls of which are mainly composed of a primary space and a secondary space, each of the spaces comprising a thermally insulating layer and a sealed layer, respectively ensuring the maintenance of the liquid natural gas. at -163 ° C and the capacity of liquid natural gas in the tank.

However, a liquid natural gas leak can occur at the sealed layer of the primary space, for example due to wear or due to improper assembly of the gasket. the waterproof layer of the primary space. The liquid natural gas contained in the tank then infiltrates into the primary space and invades the thermally insulating layer of the primary space. The liquid natural gas then spreads throughout the thermally insulating layer of the primary space.

To access and repair the leak in the waterproof layer, the tank containing liquid natural gas must be emptied. The liquid natural gas is thus evacuated from the tank, for example by known means which aim to discharge the liquid natural gas out of the damaged tank. After this step of emptying the vessel, a significant amount of liquid natural gas may remain in the thermally insulating layer of the primary space. Since the internal volume of the vessel is empty, there is no longer a pressure balance between the thermally insulating layer of the primary space and the internal volume. The weight of this LNG in the thermally insulating layer of the primary space pushes the sealed layer towards the internal volume of the vessel, which can damage the vessel. In addition, the nitrogen injected into the tank and at a temperature higher than the temperature of the liquid natural gas initially contained in the tank, fills the internal volume of the latter, thus increasing the temperature within the internal volume of the tank. This hotter nitrogen increases the temperature of the walls of the tank. The temperature of the liquid natural gas infiltrated into the walls of the vessel then increases, causing the state of the natural gas to change from a liquid state to a gaseous state. This vaporization of natural gas then causes an increase in the pressure on the walls of the vessel by exerting a force deforming the thermally insulating layer from the primary space towards the internal volume of the vessel. Depending on the quantity of natural gas infiltrated into the vessel walls, the vaporization of the latter at least partially damages the vessel walls, in particular by tearing off the sealed layer constituting the vessel wall.

In this context, the present invention proposes a perforation device making it possible to produce an orifice of sufficient diameter in the sealed layer of the primary space to allow the natural gas infiltrated into the thermally insulating layer to reach the internal volume of the tank very quickly. , and this while avoiding increasing the pressure exerted on the wall or walls of this tank. The object of the present invention is therefore to facilitate the evacuation of the liquid natural gas infiltrated into the thermally insulating layer of the primary space.

For this, the main object of the present invention is a perforation device for a sealed and thermally insulating tank configured to contain a fluid, characterized in that the perforation device comprises an actuating means and a perforation member of the tank, the actuating means being configured to generate movement of the perforating member.

The perforator is configured to perforate the vessel, the actuator being adapted to allow or block movement of the perforator. The actuating means comprises at least a fixed part and a movable part. The fixed part of the actuating means allowing the perforation device to be held in position in space, by fixing it to another object, for example. The mobile part helps set the perforating member in motion, the latter performing the action of perforating the tank.

The vessel is configured to contain a fluid, advantageously liquid natural gas (LNG), at a temperature of around -163 ° C at atmospheric pressure. The tank is thus thermally insulated, maintaining a cryogenic temperature being essential to maintain the fluid in the liquid state. In addition, the tank is sealed, preventing the leak and / or loss of the fluid contained in the tank.

The tank is delimited in space by a plurality of walls. These walls generally take the form of a rectangular parallelepiped. The perforation device makes it possible to partially perforate at least one of the walls of the plurality of walls of the vessel, advantageously the bottom wall of the vessel, and thus produces a sufficiently large section hole to allow the return of the infiltrated natural gas. in the thickness of the walls towards the inside of the tank.

According to an optional characteristic of the invention, the actuating means comprises at least one frame, a drum and a cable connecting the perforation member to the drum, the drum being configured to be rotated about an axis of rotation. and driving the winding or unwinding of the cable around the drum. The frame houses the drum and at least part of the cable. The frame is an element of the fixed part of the actuating means, the drum and the cable being for their part elements of the movable part of the actuating means.

The drum is advantageously cylindrical in shape and movable in rotation about an axis of rotation. The means for actuating the perforating member also includes a crank for manually driving the rotating drum.

The cable comprises a first end integral with the drum and a second end integral with the perforation member. Thus, the rotation of the drum in one direction of rotation or in the opposite direction of rotation causes the cable to be wound or unwound around the drum. The cable being integral with the perforation member, the perforation member is thus suspended at the end of the cable. The rotation of the drum causes the movement of the perforator, either to raise it, or to let it fall by gravity to perforate the waterproof layer, or to lower it and take a reference on the bottom wall of the tank.

The cable is made of metallic or synthetic material. One can also imagine that the cable is made partly of a synthetic material and partly of a metallic material.

According to another optional feature of the invention, the perforating member comprises at least one perforating head and a body, each extending longitudinally one after the other.

The perforation member includes a first portion consisting of the body by which the perforation member is integral with the cable and a second portion consisting of the perforation head configured to perform the perforation action.

The body is an element here ensuring the connection between the cable and the perforation head, the body not directly participating in the perforation of a wall of the tank. The body imparts inertia through its mass which allows the perforation member to fulfill its function of breaking through the primary sealed layer of the tank.

The perforation head is a cylinder, one of the ends of which is bevelled, so as to form a perforation point. The perforation head is the element of the perforation member performing the action of perforating the wall of the tank. The perforation head longitudinally extends the body of the perforation member. One can imagine that the body generally takes the form of a cylinder, the perforation head axially extending the cylinder forming the body at one of its ends.

According to another optional feature of the invention, the body has a first longitudinal end integral with the perforation head and a second longitudinal end integral with the cable.

The body extends between a first longitudinal end and a second longitudinal end, the body being integral with the perforation head at its first longitudinal end and integral with the cable at its second longitudinal end. In other words, the body is integral on the one hand with the cable and on the other hand with the punch head, so that the punch head is opposite the cable with respect to the body.

According to another optional feature of the invention, the body includes a plurality of wings and a shaft from which the plurality of wings emerge radially.

The shaft of the body generally takes the form of a cylinder bounded by the first and second longitudinal ends from which the plurality of wings emerge radially. It is understood that the wings each emerge in a plane in which is inscribed an axis passing through the center of the cylinder and through the two longitudinal ends of the body.

The wings are flat sides of generally rectangular shape. The body includes at least three wings distributed angularly evenly around the shaft of the body. Whether the plurality of wings include three or more wings, the angular sector separating two neighboring wings, that is to say two wings separated by a space not comprising a wing, is constant regardless of the number of wings. .

The plurality of wings extend in a star shape in a plane perpendicular to the main axis of extension of the piercing member, the center of which would be represented by the shaft of the body and of which each branch of the The star would be materialized by each wing of the plurality of wings.

According to another optional characteristic of the invention, at least one wing of the plurality of wings comprises a free end defining at least in part a circumference of the body and having a coating which promotes sliding of the body. Each wing of the plurality of wings has three free ends, a first and a second free end extending from the shaft of the body outwardly of the perforating member and a third free end extending parallel to the body shaft. body shaft between the other two ends.

The third end of each of the plurality of wings helps define a circumference of the body, the third ends being the most radially outwardly projecting elements of the body.

Each of the third ends of the plurality of wings includes a coating to help decrease the frictional forces applied between the third ends of the plurality of wings and an outer member, such as a metal tube constituting the vessel. More particularly, the coating can, according to a nonlimiting example, be made of synthetic material such as for example high density polyethylene (PE-HD) or polytetrafluoroethylene (PTFE), otherwise called Teflon. This type of coating makes it possible to reduce the frictional forces between the third ends of the plurality of wings and a metal element, for example.

According to another optional feature of the invention, the body carries a disc at its second longitudinal end.

The disc is thus integral with the body at the level of the second longitudinal end of the body.

The disc extends primarily in a plane perpendicular to the longitudinal axis of the shaft, this axis also passing through a center of the disc.

The function of the disc is to keep the cable above the perforation member, especially when the latter is installed in a tube. In this way, the cable does not come between the perforator and the tube.

According to another optional feature of the invention, the disc has at least one through opening.

A through opening is understood to mean an opening opening out on either side of the disc, a fluid thus being able to circulate through the disc by circulating through the through opening. The through opening can be closed on its periphery and formed an orifice crossing. Alternatively, the through opening can also be opened on the outer circumference of the disc and formed a through groove.

The disc can include a plurality of through openings. The through opening or the plurality of through openings are specially sized so as not to slow down the fall of the piercing member during its release. In fact, the tube may contain fluid, and the presence of a hole in the disc thus allows fluid to flow through the disc without slowing down the fall of the perforator.

The disc has at least one through groove allowing the passage of the cable.

The through groove extends from a periphery of the disc and towards the center of it. The through groove allows mounting of the disc on the perforating member once the latter is linked to the cable connecting the body to the drum. Indeed, when mounting the disc on the perforating member, the disc is mounted on the body by inserting the cable through the groove, from the periphery of the disc to the center thereof. The through groove of the disc facilitates the mounting of the disc on the body since the cable may have been previously attached to the body.

According to another optional feature of the invention, the disc is at least partly made of material which promotes the sliding of the disc.

The disc is at least partly made of synthetic material, such as for example high density polyethylene (PE-HD) or polytetrafluoroethylene (PTFE), otherwise called Teflon. It will be understood that the disc can be brought into contact with a surface at the level of its periphery, the material favoring the sliding of the disc being on this surface.

At least the periphery of the disc is of disc slip material, but the disc assembly may be of disc slip material without departing from the scope of the invention. In addition and according to another embodiment, the disc can also be made of metallic material and be covered at least on its periphery by a synthetic material, such as those described above.

According to another optional characteristic of the invention, the disc has a diameter less than or equal to a diameter in which the free ends of the plurality of wings fit. According to another optional characteristic of the invention, the actuating means comprises a means for blocking the rotation of the drum, the blocking means being configured to release the perforation member and obtain its fall.

The drum has at least one opening configured to accommodate the means for blocking the rotation of the drum. The means for blocking the rotation of the drum comprises at least one rod, the rod having a rectilinear portion surrounded at least in part by a sleeve made of material favoring the extraction of the blocking means from the opening of the drum, such as polyethylene high density (PE-HD) or polytetrafluoroethylene (PTFE), otherwise known as Teflon.

When the rod is housed in the opening of the drum, the latter cannot be rotated, the perforating member then being immobilized. The extraction of the rod from the drum frees the rotation of the drum, thus allowing the perforation member to fall.

The subject of the invention is also a sealed and thermally insulating tank configured to contain a fluid, the tank comprising a plurality of walls, characterized in that the tank comprises a tube passing through at least one of the walls of the tank and s' extending between a first end formed inside the tank and a second end formed outside the tank, the tank comprising a perforating device according to any one of the preceding characteristics.

The vessel is capable of storing a fluid, the plurality of vessel walls providing sealing and thermal insulation of said vessel. The tank also includes a perforation device comprising at least one of the features described above. It is understood here that the tank and the perforating device are two separate objects which can cooperate with each other.

The tank is thus delimited in space by the plurality of walls, the plurality of walls advantageously taking a parallelepipedal shape.

The tube passes through one of the walls of the plurality of walls of the tank, advantageously a ceiling, having a first end opening out inside the tank and a second end. end opening to the outside of the tank. The end opening inside the tank is close to a bottom wall of the tank.

The perforation device is installed at the end of the tube opening out to the outside of the tank, so that the perforating member can be in motion between the first and second ends of the tube, or even up to the wall. bottom of the tank.

According to another optional feature of the invention, the perforating member is disposed in the tube, the drum winding the cable to hoist the perforating member.

It is understood that the perforation member can be partly set in motion in the tube by virtue of the rotation of the drum, the direction of rotation of the drum winding or unwinding the cable around the drum, which has the consequence of bringing together or of move the perforation member of the drum away from the bottom wall of the tank.

According to another optional feature of the invention, the perforator and the tube are configured so that the perforator slides in the tube.

The perforator thus has a section smaller than the section of the tube, in order to avoid jamming the perforator in the tube.

It is understood that in order for the perforator to be able to move in the tube, the circumference in which the free ends of the plurality of wings are at least partially inscribed is necessarily smaller than the internal section of the tube.

According to another optional characteristic of the invention, each wall of the plurality of walls comprises successively in the direction of the thickness from the outside towards the inside of the tank, a secondary thermal insulation barrier, a membrane of secondary waterproofing, a primary thermal insulation barrier and a primary waterproofing membrane and intended to be in contact with the fluid contained in the tank, the primary waterproofing membrane having a perforation zone arranged opposite the end of the tube opening inside the tank.

The secondary thermal insulation barrier and the secondary waterproofing membrane form a secondary space of the vessel, while the primary thermal insulation barrier and the primary waterproofing membrane form a primary space of the vessel. It is also understood that the secondary waterproofing membrane is carried by the secondary thermal insulation barrier while being in contact with the primary thermal insulation barrier.

Thermal insulation barriers help maintain the temperature of the fluid stored in the tank by limiting heat exchange between the environment outside the tank and the inside of the tank. The sealing membranes prevent any leakage of fluid to the outside of the tank.

The perforation zone is characterized by a thinning of the primary waterproofing membrane facilitating the perforation of the latter by the perforation member. The tube is positioned so that the end opening inside the tank is facing the perforation area.

According to another optional feature of the invention, the primary waterproofing membrane forms a stud comprising at least one flat area at the level of the perforation area.

The stud allows the perforation area to be brought closer to the end opening inside the tank, reducing the risk that the perforator will puncture the secondary waterproofing membrane, after having perforated the primary waterproofing membrane. The perforation member perforates the flat zone of the stud, the latter advantageously facing the end opening inside the vessel of the tube.

According to another optional characteristic of the invention, the length of the perforation head following the direction of movement of the perforator is less than the thickness of the primary insulating barrier or else the thickness corresponding to the sum of the thickness of the primary insulating barrier and the height of the stud. This advantageously makes it possible to avoid perforating the secondary membrane by creating a stop via the primary membrane at the level of the plurality of wings.

The invention further relates to a vessel comprising a tank according to any one of the preceding characteristics.

The vessel comprises the vessel capable of storing a fluid, the plurality of vessel walls ensuring the sealing and thermal insulation of said vessel. The vessel also includes a perforation device comprising at least one of the features described above. The subject of the invention is also a method for perforating a tank fitted to a ship according to any one of the preceding characteristics, characterized in that a first step consists in installing the perforating device at the level of the second end.

The first step is to position the actuating means of the piercing device at the second end of the tube, the piercing member being installed in the tube also at the second end of the tube.

According to another characteristic of the invention, a second step consists in sliding the perforating member in the tube to bring it against a bottom wall of the tank.

It is understood that the second step consists in bringing, that is to say lowering in a controlled manner, the perforating member in the tube against a bottom wall of the tank. To do this, the perforator slides in the tube.

According to another characteristic of the invention, a third step consists in positioning the perforation member in the tube at a release height, then in blocking a constituent drum of the perforation device once the perforation member is positioned at said height. release.

The user positions the perforator at a certain height, such as three meters, and then blocks the rotation of the drum to accommodate the perforator at that height. To ensure that the measurement of the release height of the perforation member is correct, the perforation member is positioned on the bottom wall of the tank so as to take a reference. This position is then referred to as the measurement start point and acts as the starting reference for the release height.

According to another characteristic of the invention, a fourth step consists in releasing the perforation member.

The user releases the rotation of the drum to free the perforating member and let it crash against the bottom wall of the tank. Driven by its weight towards the perforation zone, the perforation member accumulates kinetic energy which it will transmit in the form of mechanical energy at the time of its impact on the perforation zone. The height is set so that the perforator can accumulate sufficient kinetic energy to perforate the primary waterproofing membrane. According to an optional characteristic of the invention, the second step, the third step, the fourth step are repeated until the primary waterproofing membrane is perforated.

According to an optional feature of the invention, a fourth step consists of hoisting the perforating member into the tube.

Other characteristics, details and advantages of the invention will emerge more clearly on reading the description which follows, on the one hand, and of several embodiments given by way of indication and not by way of limitation with reference to the appended schematic drawings on the other hand. share, on which:

[Fig. 1] is a sectional diagram of a tank equipped with a perforation device according to the invention;

[Fig. 2] is a cross section of a means for actuating the perforating device according to Figure 1;

[Fig. 3] is a perspective view of the perforating member of the perforating device according to Figure 1;

[Fig. 4] is a perspective view of a constituent locking means of the actuating means of the perforation device.

The characteristics, variants and the different embodiments of the invention can be associated with each other, in various combinations, as long as they are not incompatible or exclusive with respect to each other. It is in particular possible to imagine variants of the invention comprising only a selection of characteristics described below in isolation from the other characteristics described, if this selection of characteristics is sufficient to confer a technical advantage and / or to differentiate the invention. compared to the state of the prior art.

First, in Figure 1 is shown a sealed and thermally insulating tank 2 delimited in space by a plurality of walls 4, the tank 2 generally taking the form of a rectangular parallelepiped of which only four of its walls are illustrated. here. The tank 2 is configured to contain and / or store a fluid, and more particularly a cryogenic liquid, such as for example liquid natural gas or liquefied petroleum gas. According to a non-limiting example, this type of tank 2 is used in maritime transport, as tank for transporting liquid natural gas, or as a fuel tank for a ship. Furthermore, this tank 2 can also be used for onshore storage of natural gas.

Natural gas is denser in liquid form than in gaseous form, so the storage of natural gas is quantitatively more important when natural gas is in liquid form. Natural gas is in liquid form at atmospheric pressure at a temperature of -

163 ° C.

Vessel 2 is configured to maintain liquid natural gas at a temperature of no more than -163 ° C. For this, each wall of the plurality of walls 4 of the tank 2 comprises successively in the direction of the thickness from the outside to the inside of the tank 2, a secondary space 16 and a primary space 14 sealed and independent l 'from each other.

The secondary space comprises a secondary thermal insulation barrier 6 and a secondary waterproofing membrane 8 carried by the secondary thermal insulation barrier 6. The primary space comprises a primary thermal insulation barrier 10 resting against the membrane d. secondary sealing 8 and a primary sealing membrane 12 carried by the primary thermal insulation barrier 10. This primary sealing membrane 12 is intended to be in contact with the fluid contained in the tank 2.

The secondary thermal insulation barrier 6 is in contact with the external environment of the tank 2, in particular with a support structure. In the case where the tank is installed on a ship, the secondary thermal insulation barrier 6 is for example in contact with an internal hull of the ship. The secondary thermal insulation barrier 6 thus has an external face 18, turned towards the external environment of the tank 2. The secondary sealing membrane 8 is for its part in contact on the one hand with the thermal insulation barrier. secondary 6 and on the other hand with the primary thermal insulation barrier 10 which carries the primary waterproofing membrane 12. The thermal insulation barriers 6, 10 participate in maintaining the temperature inside the tank 2 while that the waterproofing membranes 8, 12 form an impermeable layer to the fluids that the tank 2 could contain. According to the invention, the tank 2 comprises a perforation device 32 comprising at least one actuating means 34 and a perforating member 36 of the vessel 2, the actuating means 34 being configured to set the actuating member in motion. perforation 36. This is how the actuating means 34 can hoist the perforation member 36, or even authorize its release.

The perforation device 32 is configured to pierce the primary waterproofing membrane 12 and form an orifice connecting the internal volume of the primary thermal insulation barrier 10 to an internal volume 15 of the tank 2, in order to be able to rapidly evacuate the fluid. infiltrated into the primary space 14 of the plurality of walls 4, during the unloading of the fluid contained in the tank 2, without causing the destruction of the plurality of walls 4 of the tank 2.

The description of the perforation device 32 and of a method for perforating the tank 2 will be made following the description to come of a tube 38 of the tank 2 guiding the perforating member 36 of the perforating device 32.

The tank 2 comprises at least one tube 38 passing through at least one of the walls of the tank 2, this wall also being referred to in the remainder of the description by the terms "tank ceiling 40". The tube 38 extends longitudinally between a first end 42 opening into the internal volume 15 of the tank 2 and a second end 44 opening out to the outside of the tank 2, the tube 38 extending substantially along an axis vertical A between these two ends. In the remainder of the description, the terms "inner end 42" will be used to also refer to the first end 42 of the tube 38 which extends inside the tank 2, these two expressions referring to the same object. Likewise, the terms "outer end 44" will be used to refer to the second end 44 of the tube 38 which is disposed outside the vessel 2, these two expressions thus referring to the same object.

The tube 38 thus comprises two portions, an outer portion 46 which extends between the outer end 44 of the tube 38 and the tank ceiling 40, and an inner portion 48 which extends between the inner end 42 of the tube 38. and the tank ceiling 40. Advantageously, the inner end 42 of the tube 38 is close to a wall opposite the tank ceiling 40 with respect to inside the tank 2, the opposite wall being referred to in the remainder of the description as "tank bottom 50". Thus, the internal portion 48 of the tube 38 extends from the top of the tank 40 through the tube 38 towards the bottom of the tank 50, without however touching the latter.

The tube 38 may include, at the level of the outer portion 46, an inlet 52 of a device for measuring the level of fluid contained by the tank 2, the measuring device not being shown in the figures. The tube 38 can therefore adapt a function of measuring the level of fluid in the tank, in addition to the function that it fulfills with regard to the perforation device 32 according to the invention.

Here, the inlet 52 is separate from the outer end 44 of the tube 38. However, a tube 38 as described above having an inlet 52 of the measuring device positioned at the outer end 44 of the tube 38 does not. would not be outside the scope of the invention.

The tube 38 is hollow between the outer end 44 and the inner end 42. In other words, the tube 38 has a recess 54 delimited by an inner face 33 of the tube 38 extending between each of its ends 42, 44, the recess 54 being terminated by an external mouth 56, at the level of the external end 44 of the tube 38, and by an internal mouth 58, at the level of the internal end 42 of the tube 38. When the perforating device 32 is installed on the tube 38, the perforating member 36 slides in the recess 54 of the tube 38 between each of the ends 42, 44 of the tube 38.

In addition, when the tank 2 contains a fluid, the tube 38 is at least partially immersed in the fluid, the latter at least partially filling the recess 54 of the internal portion 48 of the tube 38. In this way, the device measuring device can be positioned in the tube 38 at the level of the external portion 46 of the latter and reach the inside of the tank 2 to measure the level of fluid present in the tube 38, this level being assimilated to a quantity of fluid contained in the tank 2.

The interior mouth 58 of the tube 38 is opposite at least part of the bottom of the tank 50. More particularly, the interior mouth 58 is opposite a perforation zone 60 of the positioned on the bottom of the tank 50. The perforation zone 60 is defined as such because the primary waterproofing membrane 12 is of a thickness less than or equal to the level of this zone compared to the rest of the tank bottom 50, the thickness of the primary waterproofing membrane 12 being measured in a direction perpendicular to a major extension plane of the primary waterproofing membrane 12. The primary waterproofing membrane 12 can thus be perforated more easily by the perforation device 32.

The perforation of the primary waterproofing membrane 12 must not, however, affect the secondary space 16, the perforation member 36 thus not having to reach the secondary waterproofing membrane 8.

For this, the perforation zone 60 takes the form of a stud 62 which emerges from the primary waterproofing membrane 12 and which comprises a flat zone 64. The stud 62 extends towards the internal volume 15 of the tank 2 of so that the flat zone 64 is opposite the interior mouth 58 of the tube 38. In this configuration, the perforation member 36 perforates the primary sealing membrane 12 at the level of the flat zone 64 without reaching the sealing membrane secondary 8.

Furthermore, the tube comprises a means 55 for stopping the descent of the perforating member 36 at the level of the inner mouth 58 of the tube. This stop means takes, for example, the form of a welded disc extending mainly in a plane perpendicular to the vertical axis A. The disc comprises an advantageously circular hole configured so that a part of the member of perforation reaches the primary waterproofing membrane 12 without the perforation member 36 completely coming out of the tube 38.

According to the invention, the tube 38 carries the perforation device 32 disposed at the outer end 44 of this tube 38.

The perforating device 32 comprises the actuating means 34 and the perforating member 36 of the tank 2, the actuating means 34 being configured to generate a movement of the perforating member 36. The actuating means 34 allows thus to set in motion or to immobilize the perforating member 36. In other words, the movement of the perforating member 36 is placed under the control of the actuating means 34. The actuating means 34 comprises at least a frame 66, a drum 68 and a cable 70 connecting the perforating member 36 to the drum 68. The drum 68 is configured to be rotated about an axis of rotation B on all the figures. The rotation of the drum 68 around the axis of rotation B causes the winding or unwinding of the cable 70 around the drum 68. The drum 68 is rotated here manually, in particular by means of a crank 72.

As illustrated more particularly in FIG. 2, the actuating means 34 of the perforating member 36 comprises a manual system for rotating the drum 68, this manual system comprising at least the crank 72. The means for rotating the drum 68. actuation 34 of the perforation device 32 can alternatively be motorized or even automated without thereby departing from the scope of the invention.

The crank 72 extends along a transverse axis C perpendicular to the vertical axis A between the handle 74 and the inner end 76 of the crank 72. The handle 74 of the crank 72 allows the user to put in movement the actuating means 34 of the perforating device 32, in particular by rotating the crank 72 around the transverse axis C. The inner end 76 of the crank 72 comprises a toothed wheel 78 of the drum 68, and is held in place. position by a first rotation bearing 80 of the frame 66. The crank 72 is also supported in addition to the first rotation bearing 80 by a second rotation bearing 82 of the frame 66, this second rotation bearing 82 being in contact with the crank 72 between the handle 74 and the inner end 76 of the crank 72. These bearings for rotation of the crank 72 on the frame 66 ensure that the rotation of the crank 72 is maintained around the transverse axis C.

The drum 68 of the actuating means 34 comprises an element driven 84 in rotation by the toothed wheel 78 of the crank 72, the driven element 84 being for example a pinion. The driven element 84 is configured to be able to be rotated about the axis of rotation B of the drum 68. Thus, when the crank 72 is rotated about the transverse axis C by a user, the toothed wheel 78 of the crank 72 rotates around the axis of rotation B the driven element 84 of the drum 68 and the drum 68. The direction rotation of the crank 72 around the transverse axis C influences the direction of rotation of the drum 68.

The drum 68 comprises in addition to the driven element 84 a shaft 86 extending between a first side disc 85 and a second side disc 87, the side discs 85, 87 being of greater diameter than that of the shaft 86. The side discs 85, 87 are larger in diameter than that of the shaft 86. side discs 85, 87 being symmetrical to each other with respect to the shaft 86, a characteristic for one of the side discs 85, 87 can be applied to the other side disc 85, 87. The center of the drum 68, the center of the shaft 86, the center of the side discs 85, 87 and the axis of rotation B are coincident. The shaft 86 of the drum 68 secures the drum 68 to the frame 66, while allowing the rotation of the drum 68 around the axis of rotation B.

The cable 70 winds around the shaft 86 of the drum 68 between the side discs 85, 87, the latter guiding the cable 70 as it is wound up or unwound from the drum. The first side disc 85, like the second side disc 87 has at least one positioning hole 88. The positioning hole 88 is positioned here between the center of the first side disc 85 and a peripheral edge 90 of the first side disc 85, the positioning orifice 88 generally taking the form of an oblong hole, the largest dimension of which extends in a radial direction of the drum. As illustrated in FIG. 2, the first lateral disc 85 comprises a plurality of positioning orifices 88, each of the orifices 88 being formed through the first lateral disc 85 of the drum 68 and distributed angularly around the axis of rotation. B of drum 68.

The drum 68 comprises at least one advantageously colored notch 160 on one of the peripheral edges 90 of one of the lateral discs 85, 87, the notch 160 being designed to be at least partially visible by a user of the perforating device 32. Alternatively, the drum 68 includes a notch 160 on each side disc 85, 87 of the drum 68 so that the user can locate or count the revolutions of the drum while being disposed on either side.

The actuating means 34 also comprises a means 92 for blocking the rotation of the drum 68, the blocking means 92 being configured to block or release the setting. movement of the perforating member 36. More particularly, the blocking means 92 cooperates with the positioning orifice 88 to block the rotation of the drum 68 around the axis of rotation B, the blocking means 92 extending through example at least partly in the positioning hole 88.

The locking means 92, as illustrated in FIG. 4, comprises an advantageously rectangular handle 94 and a rod 96 extending from the handle 94 towards an insertion end 98 of the locking means 92 in a positioning hole 88. of the drum 68. The handle 94 is an area through which the user takes hold of the locking means 92, the rod 96 being for its part intended to be housed in the positioning orifice 88. Indeed, a portion of the rod 96 extending from the insertion end 98 towards the handle 94 fits in the positioning hole 88 of the drum 68, then blocking the rotation of the drum 68 about the axis of rotation B.

To release the rotation of the drum 68 and thus allow the fall of the perforating member, the locking means 92 is manually withdrawn from the drum 68. To facilitate its extraction from the drum 68, the locking means 92 comprises a sleeve 100 s' extending from the insertion end 98 towards the handle 94, promoting the sliding of the rod 96 in the positioning hole 88, the sleeve 100 being made at least in part of a synthetic material such as high density polyethylene ( PE-HD) or polytetrafluoroethylene (PTFE), otherwise called Teflon. This material has the characteristic of reducing the frictional forces between the locking means 92 and the drum 68. The presence of the sleeve 100 around the rod 96 at the level of the insertion end 98 facilitates the extraction of the locking means. 92 of the positioning orifice 88 of the drum 68. Taking into account the necessarily great weight of the perforating member so that it performs its mission in a liquid environment, such a sleeve 100 reduces the effort required to extract the locking means. 92 of the positioning hole 88.

As mentioned previously, the drum 68 is integral with the cable 70, the drum 68 causing during its rotation around the axis of rotation B the winding or unwinding of the cable 70 around the drum 68. When the locking means 92 is housed in the orifice of positioning 88, the winding or unwinding of the cable 70 cannot then occur.

As illustrated in Figure 2, the cable 70 of the actuating means 34 comprises a first end 102 integral with the drum 68 and a second end 104 integral with the perforating member 36. The first end 102 of the cable 70 is integral with the drum 68 at the level of the shaft 86 of the drum 68.

The actuating means 34 optionally comprises a guide element 112 of the cable 70, optimizing the winding or unwinding of the cable 70 around the drum 68.

The actuating means 34 optionally comprises a return roller 114, advantageously a shaft, around which the cable 70 can slide.

The frame 66 of the actuating means 34 comprises a plurality of sides, of which a first side 115 is in particular visible in FIG. 2, and a fixing flange 118. The fixing flange 118 of the frame 66 extends mainly in a plane. substantially perpendicular to the vertical axis A. The plurality of sides of the frame 66 and the fixing flange 118 thus delimits a space 116 in which the drum 68 and the cable 70 are housed in particular at least partially. The space 116 of the frame 66 is in communication with the external environment of the frame 66 at the level of the fixing flange 118, allowing at least part of the cable 70 to be outside the frame 66. Indeed, the first end 102 of the cable 70 connected the drum 68 is positioned inside the frame 66 in the space 116 and the second end 104 of the cable 70 is positioned outside the frame 66, the cable 70 partly passing through the space 116 of the frame 66. The second end 104 of the cable 70 is integral with the perforation 36.

The fixing flange 118 of the frame 66 is intended to be in contact with the outer end 44 of the tube 38. For this, the fixing flange 118 of the frame 66 is positioned opposite a fixing flange of the outer cover 56. of the tube 38, the fixing flange 118 of the frame 66 and the fixing flange 120 of the tube 38 being intended to cooperate with each other in order to make the frame 66 integral with the tube 38. This assembly secures the fixing device. perforation 32 on the tube 38. This assembly also provides a seal between the fixing flange 118 of the frame 66 and the fixing flange 120 of the tube 38.

Once the frame 66 is mounted on the tube 38 at the level of the outer end 44 of the tube 38, at least part of the cable 70 and the perforating member 36 is positioned in the hollow part 54 of the tube 38, this part of the cable 70 and the perforating member 36 aligning substantially along the vertical axis A, the pivot member 114 ensuring the positioning of the perforating member 36 along this axis, as illustrated in the figure 2. Positioned in this way, the perforating member 36 disposed in the tube 38 is retained in suspension at the level of the second end 104 of the cable 70. The rotation of the drum 68, causing the winding or unwinding of the cable 70 around. of the drum 68, also causes the approximation or removal of the perforating member 36 from the outer end 44 and / or the inner end 42 of the tube 38.

According to the example illustrated in Figure 3, the perforator 36 comprises at least one perforation head 122 and a body 124, each extending one after the other. More specifically, the body 124 of the perforation member 36 extends longitudinally between a first longitudinal end 126 integral with the perforation head 122 and a second longitudinal end 129 integral with the second end 104 of the cable 70. It is understood that the cable 70 is thus opposed to the perforation head 122 relative to the body 124 of the perforation member 36.

The body 124 comprises a shaft 128 delimited longitudinally by the first longitudinal end 126 and by the second longitudinal end 129 of the body 124, extending along the vertical axis A. The shaft 128 here generally takes the form of a cylinder whose center coincides with the vertical axis A. Moreover, it is more particularly the shaft 128 of the body 124 which, at each of its ends, is secured to the cable 70 and to the perforation head 122.

The shaft 128 includes a groove 130 extending from the periphery of the shaft 128 to the center of the cylinder at the second longitudinal end 129 of the body 124. This groove 130 facilitates the mounting of the cable 70 on the shaft. 128 of body 124. According to another embodiment, the shaft 128 of the perforation member 36 can comprise a fixing ring positioned more particularly at the level of the second longitudinal end 129 on which the cable 70 can be fixed.

The body 124 also carries a plurality of wings 132, each of these wings emerging radially from the shaft 128 of the body 124. Each wing of the plurality of wings 132 extends longitudinally between the first longitudinal end 126 and the second end. longitudinal 129 of the body 124 and perpendicular to the shaft 128 outwardly of the perforator 36. In other words, each wing of the plurality of wings 132 extends from the shaft 128 of the body 124. towards the outside of the perforation member 36 mainly in a plane in which the vertical axis A is inscribed.

Each wing of the plurality of wings 132 forms a rectangular flat sidewall with three free edges. A first and a second free edges 134, 136 participate in delimiting each wing at the level of the first longitudinal end 126 and of the second longitudinal end 129 of the body 124. Thus, the first and second free edges 134, 136, of each wing s 'extends substantially perpendicular to the vertical axis A. Each wing of the plurality of wings 132 comprises a third free edge 138 advantageously parallel to the vertical axis A and extending at least in part between the first edge 134 and the second edge 136 of each wing of the plurality of wings 132.

In the example illustrated in Figure 3, the plurality of wings 132 has six wings distributed so that an angular sector between each of the wings of the plurality of wings 132 is regular.

It is thus understood that the distance separating the third free edge 138 from two adjacent wings of the plurality of wings 132 is equal regardless of the adjacent wings of the plurality of wings 132 chosen to perform this measurement, the distance being measured perpendicularly to the vertical axis A. According to another embodiment, the plurality of wings 132 comprises at least three wings. When the body 124 has three wings, they are distributed around the shaft 128 of the body 124 so as to form angles of substantially 120 degrees. The third free edge 138 of each wing of the plurality of wings 132 at least partially delimits a circumference of the body 124, being inscribed in a circle which materializes this circumference.

The third free edge 138 of each wing of the plurality of wings 132 carries a coating 140 promoting the sliding of the body 124 in the tube 38. This coating 140 advantageously extends from the first edge 134 to the second edge 136 of each wing. , thus covering the whole of the third free edge 138 of each wing. The coating 140 is made of a synthetic material, such as high density polyethylene (HD-PE) or polytetrafluoroethylene (PTFE), otherwise called Teflon, in order to decrease the frictional forces between the third free edge 138 of each wing of the plurality. wings 132 of the perforation member 36 and an internal face of the tube 38. Apart from the coating 140, the perforation member 36 is advantageously made of stainless steel, so that its weight is sufficient to allow perforation of the membrane primary seal 12 at the perforation zone 60.

The body 124 carries at its second longitudinal end 129 a disc 142 preventing the passage of the cable 70 at the level of the plurality of wings 132 when the perforating member 36 is in the recess 54 of the tube 38. Indeed, when the perforating member 36 is stopped at the end of its fall, the drum 68 continues to be driven in rotation by the weight of the cable 70. A part of the cable 70 accumulates on the disc 142, the latter hindering the passage of the cable 70 between the plurality of wings 132 and the internal face 33 of the tube 38. The disc 142 extends mainly in a plane perpendicular to the vertical axis A, this axis coinciding with the center of the disc 142.

The disc 142 has an upper face 144 and a lower face, not visible in the figures, opposite to each other, the lower face facing towards the shaft 128 and towards the plurality of wings 132 of the body. 124. On the other hand, the diameter of the disc 142 is equal to or less than a diameter in which the third free edges 138 of the plurality of wings 132 fit. However, the diameter of the disc 142 must be large enough to accommodate it. preventing cable 70 from passing through a space between a peripheral edge 148 of disc 142 and an inner surface of tube 38.

The disc 142 comprises at least one through opening 146, and advantageously a plurality of through openings 146, these openings allowing fluid to flow through the disc 142 when the latter falls into the tube 38. The term “through” is understood to mean that the opening opens onto the lower face and the upper face 144 of the disc 142, thus connecting the two faces of the disc 142. The disc 142 as illustrated in FIG. 3 comprises a plurality of through openings 146 arranged close to the radially outer periphery of the disc 142. The openings of the plurality of through openings 146 can be closed on their peripheries thus constituting through orifices, or open on the outer circumference of the disc then constituting through grooves. Indeed, the disc 142 has a peripheral edge 148 which extends between the upper and lower faces of the disc 142, the plurality of through openings 146 being formed close to this peripheral edge 148 without however being in contact with the latter. here.

The peripheral edge 148 has a chamfered shape between the upper face 144 and the lower face of the disc 142. It is understood that the peripheral edge 148 advantageously has three faces: a first face extending in a plane perpendicular to the plane of extension of the faces. upper 144 and lower of the disc 142, a second face providing the connection between the upper face 144 and the first face of the peripheral edge 148 and a third face providing the connection between the lower face of the disc 142 and the first face of the peripheral edge 148.

The disc 142 includes a groove 150 extending from the peripheral edge 148 of the disc 142 to the center thereof. The groove 150 is formed so as to be aligned with the groove 130 of the shaft 128, the groove 150 allowing, similarly to the groove 130 of the shaft 128, the cable 70 to be mounted on the perforating member 36. It is possible to mount the cable 70 on the perforating member 36. can thus mount the disc 142 on the perforating member 36 after having attached it to the cable 70. According to another embodiment, the disc 142 comprises a closed through orifice, instead of the groove 150, through which the cable 70 passes.

The disc 142 has at least one fixing hole 152 and advantageously several fixing holes 152 making it possible to make the disc 142 integral with the shaft 128 of the body 124. For this, the fixing hole or holes 152 cooperate with fixing means. not shown in the figures, such as screws for example, to fix the disc 142 to the shaft 128 of the body 124.

The perforation member 36 comprises the perforation head 122 generally taking the form of a cylinder 121 extending between a connecting edge 154 and a perforation cone 156. The cylinder 121 has at least one groove 123 extending from it. the perforation cone 156 towards the connecting edge 154.

The perforation head 122 is integral with the body 124 at the level of the connecting edge 154, the latter thus being in contact with the first longitudinal end 126 of the body 124. The perforation cone 156 of the perforation head 122 has a conical shape up to 'to a piercing point 158.

We will now describe a method of perforating the tank 2 in which the perforating member 36 is set in motion to perforate one of the walls of the plurality of walls 4 of the tank 2.

When a leak of the fluid contained in the tank 2 through the primary sealing membrane 12 has been identified, a user places the perforation device 32 at the level of the inlet mouth of the tube 38 of the tank 2, thus constituting a first step of the perforation process. The perforation device 32 is positioned at the level of the outer mouth of the tube 38 so that the space 116 of the frame 66 is in contact with the outer mouth 56 of the tube 38 and that part of the cable 70 and the perforation 36 are disposed in the recess 54 of the tube 38 at the level of the outer end 44 of the tube 38. The cable 70 is then wound around the drum 68 to keep the perforator 36 at the level of the outer end 44 of tube 38. A second step consists in positioning the perforating member 36 at the level of the inner end 42 of the tube 38. For this, the user turns the crank 72 so that the drum 68 unwinds the cable 70 causing the descent of the cable. perforation member 36 in the tube 38 in the direction of the bottom wall of the tank 2. The descent of the perforation member 36 is thus controlled by the user turning the crank 72. To avoid any premature release of the member 36 during its descent into the tube 38, the drum 69 comprises a braking system limiting the rotational speed of the drum 68 and thus preventing the perforating member 36 from being released and breaking through one of the walls of the plurality of walls 4 of the tank 2. This braking system is reversible so that the user can remove it when he wishes to release the perforating member 36. The controlled descent of the perforating member 36 is carried out up to 'to this the piercing point 158 of the perforation member 36 comes into contact with the flat area 64 of the stud 62 of the tank bottom 50.

A third step of the perforation process consists of hoisting the perforating member 36 in the tube 38 to a release height and then blocking the drum 68 once the perforating member 36 is positioned at said height. Thus, the user raises the perforation member 36 to a determined height which depends on factors such as the thickness of the primary waterproofing membrane, or even the presence of fluid in the tube 38. By way of example, this height is three meters, measured along the vertical axis A.

With the notch 160, the user can count the number of revolutions that the drum 68 makes when the latter is hoisted before release. In the example shown here, the size of the drum 68 is configured so that the circumference of the drum 60 is approximately one meter, so that one turn of the rotating drum 68 causes the winding or unwinding of one meter of the drum. cable 70.

To hoist the perforating member 36 to three meters from the inner mouth 58 of the tube 38, the user drives the drum 68 in rotation thanks to the crank 72 and counts, thanks to the notch 160, the number of turns made by the drum 68 until it reaches the number of three. When the perforation member 36 has reached this height, the user accommodates the blocking means 92 in the drum 68 in order to block the rotation of the drum 68. A fourth step of the method consists in releasing the perforating member 36. The user thus releases the drum 68 from the locking means 92, the perforating member 36 being driven by its weight towards the flat area 64 of the stud 62 of the bottom. tank 50.

The weight of the perforator 36 propels at a sufficient speed the perforating tip 158 of the perforating member 158 towards the flat area 64 of the stud 62 of the tank bottom 50, thus generating kinetic energy. When the piercing tip 158 contacts the planar area 64, kinetic energy is converted into mechanical energy so that the piercing tip 158 perforates the primary waterproofing membrane 12 at the planar area 64 of the pad 62. Once the perforated primary waterproofing membrane 12, the perforation member 36 is raised by the user to the outer end 44 of the tube 38.

A fifth step of the perforation process then consists in hoisting the perforating member 36 into the tube 38. If the perforating member 36 has not sufficiently pierced the primary waterproofing membrane 12 following a first test , the user starts the perforation process again by positioning the perforation member 36 at the determined height from the interior mouth 58 of the tube 38 and again releasing from the perforation member 36 onto the primary waterproofing membrane 12, thus constituting a fifth step of the perforation process.

The user can thus start the perforation process again, and more particularly the second, third and fourth steps, until the primary waterproofing membrane 12 is perforated. In other words, the user repeats these three steps as long as the hole in the primary waterproofing membrane 12 is not of a sufficient area for the fluid to very quickly exit the primary thermal insulation layer and join the internal volume 15 of the tank 2.

Once the waterproofing membrane has been perforated, the unloading of the fluid contained in the tank 2 can be carried out without damaging the wall of the tank 2. In fact, the liquid natural gas infiltrated into at least one of the walls 4 joins the internal volume 15. of the tank 2 via the perforation produced by the perforation member 36 in the primary waterproofing membrane 12. In addition, the fluid infiltrated into the primary thermal insulation barrier 10 can thus be recovered, thus avoiding any risk of overpressure inside the wall of the tank which has been infiltrated. Once all the liquid natural gas has been discharged, repair of the leak as well as repair of the perforation can be carried out to give the vessel a new seal. The invention cannot however be limited to the means and configurations described and illustrated here, and it also extends to any equivalent means or configuration described and illustrated here, and it also extends to any equivalent means or configuration and to any combination. technique operating such means. In particular, the actuating means 34 of the perforation member can be at least partially motorized, or even fully automated without departing from the scope of the invention.

Claims

1. Perforation device (32) for a sealed and thermally insulating vessel (2) configured to contain a fluid, characterized in that the perforation device (32) comprises an actuating means (34) and a perforation member ( 36) of the tank (2), the actuating means (34) being configured to generate a movement of the perforating member (36).

2. Perforation device (32) according to claim 1, wherein the actuating means (34) comprises at least a frame (66), a drum (68) and a cable (70) connecting the perforation member ( 36) to the drum (68), the drum (68) being configured to be rotated about an axis of rotation (B) and to drive the winding or unwinding of the cable (70) around the drum (68).

3. A perforating device (32) according to any preceding claim, wherein the perforating member (36) comprises at least one perforating head (122) and a body (124), each extending longitudinally. 'one after the other.

4. Perforation device (32) according to claim 3, wherein the body (124) has a first longitudinal end (126) integral with the perforation head (122) and a second longitudinal end (128) integral with the cable (70). ).

A perforating device (32) according to any one of claims 3 or 4, wherein the body (124) comprises a plurality of wings (132) and a shaft (128) from which emerges the plurality of wings radially ( 132).

A perforating device (32) according to claim 5, wherein at least one wing of the plurality of wings (132) comprises a free end (138) defining at least in part a circumference of the body (124) and having a. coating (140) promoting sliding of the body (124).

7. Perforation device (32) according to any one of claims 4 to 6, wherein the body (124) carries a disc (142) at its second longitudinal end (128).

8. A perforation device (32) according to claim 7, wherein the disc (142) has at least one through opening (146).

9. Perforation device (32) according to any one of claims 7 or 8, wherein the disc (142) is at least partly made of material promoting its sliding.

10. A perforation device (32) according to any one of claims 7 to 9, wherein the disc (142) has a diameter less than or equal to a diameter in which the free ends (138) of the plurality of fit. 'wings (132).

11. A perforation device (32) according to any one of the preceding claims in combination with claim 2, wherein the actuating means (34) comprises means (92) for blocking the rotation of the drum (68), the locking means (92) being configured to release a drop from the puncture member (36).

12. Tank (2) sealed and thermally insulating configured to contain a fluid, the tank (2) comprising a plurality of walls (4), characterized in that the tank (2) comprises a tube (38) passing through at least the one of the walls of the tank (2) and extending between a first end (42) formed inside the tank (2) and a second end (44) formed outside the tank (2), the tank (2) comprising a perforation device (32) according to any one of the preceding claims.

13. Tank (2) according to claim 12 in combination with claim 2, wherein the perforating member (36) is disposed in the tube (38), the drum (68) winding the cable (70) to hoist the 'perforation member (36).

14. The vessel (2) according to any one of claims 12 or 13 in combination with claim 6, wherein the perforating member (36) and the tube (38) are configured so that the perforating member (36 ) slides in the tube (38).

15. Tank (2) according to any one of claims 12 to 14, wherein each wall of the plurality of walls (4) comprises successively in the direction of the thickness from the outside towards the inside of the tank ( 2), a secondary thermal insulation barrier (6), a secondary waterproofing membrane (8), a primary thermal insulation barrier (10) and a primary waterproofing membrane (12) and intended to be in contact with the fluid contained in the tank (2), the primary sealing membrane (12) having a perforation zone (60) arranged opposite the end of the tube (38) opening inside the tank (2) ).

16. Vessel comprising at least one tank (2) according to any one of claims 12 to

15.

17. A method of perforating a tank (2) fitted to a ship according to the preceding claim, characterized in that a first step consists in installing the perforating device (32) at the level of the second end (44) of the tube ( 38).

18. A method of perforating a tank (2) according to claim 17, wherein a second step consists in sliding the perforating member (36) in the tube (38) to bring it against a bottom wall (50). ) of the tank (2).

19. A method of perforating a tank (2) according to claim 18, wherein a third step consists in hoisting the perforating member (36) in the tube (38) to a release height, then in blocking a drum. (68) constituting the perforation device (32) once the perforation member (36) is positioned at said release height.

20. A method of perforating a tank (2) according to claim 17 or 19, wherein a fourth step consists in releasing the perforating member (36).

21. A method of perforating a tank (2) according to claim 20, the tank comprising successively in the direction of the thickness from the outside towards the inside of the tank (2), a thermal insulation barrier secondary (6), a secondary waterproofing membrane (8), a primary thermal insulation barrier (10) and a primary waterproofing membrane (12) and intended to wander in contact with the fluid contained in the tank (2 ), a process in which the second step, the third step, the fourth step are repeated until the primary waterproofing membrane (12) is perforated.