Double skin cryogenic tank equipped with at least one inspection device

Abstract

The invention relates to a tank comprising inner and outer skins (12, 16) separated by an interlayer zone (14) and at least one inspection device (20) comprising: - a first orifice (22) configured to communicate the inner zone (Int) of the tank and the interlayer zone (14) through the inner skin (12), which can be closed by a first plug (26), - a second orifice (24) configured to communicate the interlayer zone (14) and the outer zone (Ext) of the tank through the outer skin (16), which can be closed by a second plug (28), the first and second orifices (22, 24) being aligned in a radial direction, - an interlayer conduit (30) connecting the inner and outer skins (12, 14), communicating with the first and second orifices (22, 24) and comprising a bellows configured to deform in the radial direction.

Description

[0001] This application relates to a double-walled cryogenic tank equipped with at least one inspection device.

[0002] In one embodiment, a tank configured for storing a product at a cryogenic temperature comprises, from the inside out, a rigid inner skin, insulation such as, for example, multi-layer insulation (MLI), and a rigid outer skin. A vacuum of approximately 10⁻⁷ to 10⁻¹¹ bar is maintained between the inner and outer skins. This configuration provides excellent thermal insulation performance.

[0003] In one application, such a tank is used to store hydrogen in an aircraft and includes at least one outlet port connecting the tank's interior to an outlet pipe that supplies hydrogen to at least one piece of equipment (fuel cells, turboprops, or other). The outlet pipe is a double-walled pipe connected to the tank by a relatively complex fitting system, ensuring optimal fluid sealing and thermal insulation at the junction between the outlet pipe and the tank.

[0004] During operation, the inside of the tank must be inspected using an endoscopic camera to verify its integrity. One solution for introducing the endoscopic camera into the tank involves disconnecting the tank's outlet pipe to insert the camera through the outlet port. This solution is not entirely satisfactory because the connection system is relatively complex to disassemble and reassemble, and its position, which is not necessarily optimized for inspection, limits access to the tank's interior.

[0005] Document RU2002991 describes a tank configured for storing a product at a cryogenic temperature. It comprises a rigid inner skin with a first opening sealed by a first plug, a rigid outer skin with a second opening sealed by a second plug, and an intermediate conduit positioned between the inner and outer skins, rigidly connected to the inner and outer skins around the first and second openings. Assembling such a tank is complex.

[0006] Document RU 1 031 274 C describes another reservoir.

[0007] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0008] For this purpose, the invention relates to a reservoir comprising an inner skin, an outer skin and an intercalary zone between the inner and outer skins, the inner and outer skins delimiting an inner zone in contact with the inner skin and an outer zone in contact with the outer skin.

[0009] According to the invention, the tank includes at least one inspection device comprising: a first orifice configured to allow communication between the inner zone and the intercalated zone through the inner skin, a second orifice configured to allow communication between the intercalated zone and the outer zone through the outer skin, the first and second orifices being aligned in a radial direction, a first plug configured to occupy a first mounted state in which the first plug prevents any flow through the first orifice and a second dismounted state in which the first plug allows access through the first orifice, a second plug configured to occupy a first mounted state in which the second plug prevents any flow through the second orifice and a second dismounted state in which the second plug allows access through the second orifice, an intercalated conduit, positioned in the intercalated zone,featuring a first end section connected to the inner skin and communicating with the first orifice, a second end section connected to the outer skin and communicating with the second orifice, and an intermediate section forming a bellows configured to deform in the radial direction, , the inspection device comprising a watertight and permanent connection linking the intermediate conduit and a first support integral with the inner skin, and a removable and watertight connection linking the intermediate conduit and a second support integral with the outer skin or the outer skin, the inner skin of the tank comprising an inner face oriented towards the inner zone and an outer face oriented towards the intermediate zone, and the first support being connected by at least one watertight and permanent connection to the inner skin and comprising a first transverse face pressed against the outer face of the inner skin, a second transverse face opposite the first transverse face, a lateral surface comprising at least one section configured to cooperate with the first end section of the intermediate conduit and a first through orifice opening at the level of the first and second transverse faces,communicating with the first orifice and configured to cooperate with the first plug.

[0010] The inspection device allows for easy inspection of the tank's interior without needing to dismantle the tank's outlet pipe connection system. It also prevents damage to the tank's watertightness and thermal insulation. Finally, the bellows in the intermediate conduit compensate for dimensional variations between the inner and outer walls during operation, caused by temperature differences between them.

[0011] According to another characteristic, the inspection device includes at least one insulator positioned in a passage zone delimited by the intercalated conduit.

[0012] According to another feature, the inspection device includes a movable support, to which the insulation is attached, configured to insert the insulation into or remove it from the access area. According to another feature, the inspection device includes a detachable link configured to connect the movable support to the first plug and / or to a first support attached to the inner skin.

[0013] According to another feature, the inspection device includes a purge system configured to control the pressure present in a passage area delimited by the intercalated conduit and the first and second plugs in the first mounted state.

[0014] According to another feature, the purge system includes a valve having an inlet communicating with the passage area when the second plug occupies the first mounted state, an outlet, and a control configured to control a flow of fluid between the inlet and outlet.

[0015] According to another feature, the first through-hole comprises a first segment opening at the first transverse face, a second segment opening at the second transverse face which has a diameter greater than that of the first segment, and a transverse bearing face connecting the first and second segments. Additionally, the first plug comprises a cylindrical body extending between first and second end faces connected by a lateral face configured to cooperate with the second segment of the first through-hole of the first support. The first end face is oriented towards the transverse bearing face of the first through-hole when the first plug is in its first mounted state. The inspection device comprises an annular seal interposed between the first end face of the first plug and the transverse bearing face of the first through-hole of the first support.

[0016] According to another feature, the second section of the first through hole is tapped. In addition, the lateral face of the first plug has a first section adjacent to the first end face which has a diameter greater than the first section of the first through hole and less than the second section of the first through hole, and a second section, adjacent to the second end face, at least partially threaded and configured to screw into the second section of the first through hole.

[0017] According to another feature, the second section of the side face includes an annular groove to allow an element to be clipped in.

[0018] According to another feature, the first cap has an indentation on the second end face to allow it to be screwed into the first through hole.

[0019] According to another feature, the outer skin comprising an inner face oriented towards the intercalated zone and an outer face oriented towards the outer zone, the second support is connected by at least one permanent and watertight link to the outer skin and comprises a first transverse face pressed against the outer face of the outer skin, a second transverse face opposite the first transverse face and a second through orifice opening at the level of the first and second transverse faces and communicating with the second orifice, the second plug being configured to be pressed against the second transverse face and connected to the second support by a removable and watertight link.

[0020] According to another feature, the second through-hole has a first section at the first transverse face and a second section, with a diameter greater than that of the first section, configured to house the removable and watertight connection, as well as a transverse bearing surface connecting the first and second sections. In addition, the intermediate conduit includes a tubular extension having a tubular portion configured to fit at least partially into the second through-hole. The removable and watertight connection includes a thread on the tubular portion of the tubular extension of the intermediate conduit and a nut configured to screw onto the tubular portion of the tubular extension and bear against the transverse bearing surface of the second support.

[0021] According to another feature, the tubular extension includes a first tubular portion cooperating with the second end section of the intercalated conduit, a second tubular portion cooperating with the nut of the removable and watertight connection, and a crown configured to press against the second support, the removable and watertight connection including a gasket intercalated between the crown and the second support.

[0022] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which: There figure 1 is a perspective view showing a partial tear-off of a double-walled tank, The figure 2 is a cross-section of part of a tank equipped with an inspection device illustrating one embodiment of the invention, The figure 3 is a cross-sectional view of part of the inspection device visible on the figure 2 illustrating a first stage of assembly, The figure 4 is a cross-sectional view of part of the inspection device visible on the figure 2 illustrating a second assembly stage, The figure 5 is a cross-sectional view of part of the inspection device visible on the figure 2 illustrating a third assembly stage, The figure 6 is a cross-sectional view of the inspection device visible on the figure 2 illustrating a vacuuming step, The figure 7 is a cross-sectional view of the inspection device visible on the figure 2 illustrating a pre-inspection airing step, The figure 8 is a cross-sectional view of the inspection device visible on the figure 2 illustrating the initial stages of dismantling prior to inspection, The figure 9 is a cross-sectional view of the inspection device visible on the figure 2 illustrating a final dismantling stage prior to inspection, The figure 10 is a cross-sectional view of the inspection device visible on the figure 2 during an inspection.

[0023] According to an embodiment visible on the figures 1 et 2 A tank 10 configured to store a product at a cryogenic temperature comprises a rigid inner skin 12, an interlayer zone 14, and a rigid outer skin 16 positioned around the inner skin 12. The tank 10 delimits an inner zone Int in contact with the inner skin 12 and an outer zone Ext in contact with the outer skin 16. The inner skin 12 has an inner face F12 oriented towards the inner zone Int of the tank 10 and an outer face F12' oriented towards the interlayer zone 14. The outer skin 16 has an inner face F16 oriented towards the interlayer zone 14 and an outer face F16' oriented towards the outer zone Ext of the tank 10.

[0024] To enhance thermal insulation, at least one MLI (Multi-Layer Insulation) type insulation 18 is positioned in the interlayer zone 14. For example, the insulation 18 comprises several layers stacked one on top of the other from the inner skin 12 to the outer skin 14. The invention is not limited to this type of insulation. In addition, the interlayer zone 14 has a vacuum of approximately 10⁻⁷ to 10⁻¹¹ bar.

[0025] According to one configuration, each of the inner and outer skins 12, 16, comprises a cylindrical central part 12.1, 16.1 and two dome-shaped end walls 12.2, 12.3, 16.2, 16.3 connected in a hermetic manner at each end of the cylindrical central part 12.1, 16.1. Of course, the invention is not limited to this geometry for the tank 10.

[0026] According to one application, such a tank is used to store hydrogen in an aircraft and includes at least one outlet port allowing communication between the inside of the tank and an outlet pipe. Of course, the invention is not limited to this application.

[0027] As illustrated on the figure 2 The tank 10 is equipped with at least one inspection device 20. According to one configuration, the inspection device 20 is positioned at the cylindrical central parts 12.1, 16.1 of the inner and outer skins 12, 16. Of course, the tank 10 can include several inspection devices 20 not necessarily all positioned at the cylindrical central parts 12.1, 16.1. Thus, an inspection device can be positioned at the end walls 12.2, 12.3, 16.2, 16.3.

[0028] The inspection device 20 comprises a first orifice 22 configured to connect the inner zone Int and the intermediate zone 14 through the inner skin 12, a second orifice 24 configured to connect the intermediate zone 14 and the outer zone Ext through the outer skin 16, the first and second orifices 22, 24 being substantially aligned in a radial direction perpendicular to the inner or outer skin 12, 16, a first plug 26 configured to occupy a first mounted state in which it prevents any flow through the first orifice 22 and a second dismounted state in which it allows access through the first orifice 22, a second plug 28 configured to occupy a first mounted state in which it prevents any flow through the second orifice 24 and a second dismounted state in which it allows access through the second orifice 24, as well as an intermediate conduit 30,positioned in the intercalated zone 14, having a first end section 30.1 connected directly or indirectly to the inner skin 12 and communicating with the first orifice 22, a second end section 30.2 connected directly or indirectly to the outer skin 16 and communicating with the second orifice 24, and an intercalated section 30.3 forming a bellows configured to deform in the radial direction and possibly in a direction perpendicular to the radial direction in order to compensate for an axial offset between the first and second orifices 22, 24. Thus,The intermediate conduit 30 is configured to occupy a first state in which it has a first dimension taken along the radial direction and a second state in which it has a second dimension along a radial direction shorter than the first dimension. The bellows of the intermediate section 30.3 is configured to obtain a length reduction between the first and second dimensions of at least 20%.

[0029] According to one configuration, to reinforce the seal, a tubular insulation 31 is inserted between the intermediate conduit 30 and the layers of insulation 18 provided in the intermediate zone 14. As an example, this tubular insulation 31 is an MLI type insulation.

[0030] According to one configuration, the first state corresponds to a rest state. Thus, in the absence of stress, the intermediate conduit 30 occupies the first state. The intermediate conduit 30 is configured to deform elastically, in the presence of a compressive stress tending to compress it, to transition from the first state to the second state. As soon as the compressive stress is removed, the intermediate conduit 30 automatically returns to the first state.

[0031] According to one embodiment, the intermediate conduit 30 is metallic, such as stainless steel or titanium alloy for example.

[0032] This intermediate conduit 30, equipped with a bellows, allows for compensation of dimensional variations between the inner and outer skins 12, 16, during operation, due to temperature differences between the inner and outer skins 12, 16.

[0033] When the first and second plugs 26, 28 are in the first mounted state, they delimit with the intermediate conduit 30 a passage zone 32. When the first and second plugs 26, 28 are each in the second dismounted state, the passage zone 32 allows communication between the inner zone Int of the tank 10 and the outer zone Ext.

[0034] Since the interlayer duct 30 is directly or indirectly connected to each of the inner and outer skins 12, 16 in a sealed manner, the removal of the first and second plugs 26, 28 to carry out an inspection has no influence on the vacuum level of the interlayer area 14 outside the interlayer duct 30.

[0035] The inspection device 20 includes a first support 34, integral with the inner skin 12, configured to receive the first plug 26.

[0036] This first support 34 has a shape of revolution about an axis of revolution A34. It has a first transverse face 36 (approximately perpendicular to the axis of revolution A34) pressed against the outer face F12' of the inner skin 12, a second transverse face 38 (approximately perpendicular to the axis of revolution A34) opposite the first transverse face 36, and a first through-hole 40, opening at the level of the first and second transverse faces 36 and 38, communicating with the first hole 22 and having an axis coinciding with the axis of revolution A34. The first transverse face 36 has a curvature identical to that of the outer face F12' of the inner skin 12. The first support 34 is positioned so that the first through-hole 40 is substantially coaxial with the first hole 22.

[0037] The first support 34 includes a lateral surface 42 which has at least one section configured to cooperate with the first end section 30.1 of the intercalated conduit 30. According to one embodiment, the lateral surface 42 of the first support 34 includes first, second and third cylindrical sections 42.1, 42.2, 42.3 having stepped diameters, the first cylindrical section 42.1 adjacent to the first transverse face 36 having a diameter greater than the second cylindrical section 42.2 which itself has a diameter greater than the third cylindrical section 42.3 adjacent to the second transverse face 38.

[0038] The first through orifice 40 is configured to cooperate with the first plug 26. It comprises a first section 40.1 opening at the first transverse face 36, a second section 40.2 opening at the second transverse face 38 which has a diameter greater than that of the first section 40.1, and a transverse bearing face 40.3 connecting the first and second sections 40.1, 40.2. The first section 40.1 has a diameter less than that of the first orifice 22.

[0039] The first support 34 is connected to the inner skin 12 by at least one permanent, watertight connection 41. In one configuration, the first support 34 is connected to the inner skin 12 by a first peripheral weld bead 41 linking the first cylindrical section 42.1 of the first support 34 and the outer face F12' of the inner skin 12, and by a second peripheral weld bead 41' linking the edge of the first opening 22 and the first transverse face 36 of the first support 34. Of course, other solutions are possible for watertightly connecting the first support 34 and the inner skin 12. Alternatively, the first support 34 and the inner skin 12 form a single piece.

[0040] The first plug 26 comprises a cylindrical body extending between first and second end faces 44.1, 44.2 connected by a lateral face 46 configured to cooperate with the second section 40.2 of the first through orifice 40 of the first support 34. According to one arrangement, the first end face 44.1 is oriented towards the transverse support face 40.3 of the first through orifice 40 when the first plug is in the first mounted state.

[0041] According to one configuration, the second section 40.2 of the first through hole 40 is tapped and the side face 46 of the first plug 26 has a first section, adjacent to the first end face 44.1, which has a diameter greater than the first section 40.1 of the first through hole 40 and less than the second section 40.2 of the first through hole 40, and a second section, adjacent to the second end face 44.2, at least partially threaded and configured to screw into the second section 40.2 of the first through hole 40. According to one embodiment, the second section of the side face 46 includes an annular groove to allow an element to be clipped.

[0042] To ensure a seal between the first cap 26 and the first support 34, the inspection device includes an annular seal 48 interposed between the first end face 44.1 of the first cap 26 and the transverse bearing face 40.3 of the first through orifice 40 of the first support 34. This annular seal 48 is compatible with the product stored in the tank 10.

[0043] The first cap 26 has a recessed imprint 50 at the level of the second end face 44.2 to allow it to be screwed into the first through hole 40. Depending on one configuration, the imprint 50 has a hexagonal section.

[0044] The inspection device 20 includes a sealed and permanent connection 52 linking the first end section 30.1 of the interlayer conduit 30 and the first support 34 or the inner skin 12. According to one configuration, the first end section 30.1 of the interlayer conduit 30 is fitted around the second cylindrical section 42.2 of the first support 34 and connected to the latter by a peripheral and sealed weld.

[0045] Of course, the invention is not limited to this embodiment for the first support 34 and the first stopper 26.

[0046] The inspection device 20 includes a second support 54, integral with the outer skin 16, configured to receive the second plug 28.

[0047] This second support 54 has a shape of revolution about an axis of revolution A54. It has a first transverse face 56 (approximately perpendicular to the axis of revolution A54) pressed against the outer face F16' of the outer skin 16, a second transverse face 58 (approximately perpendicular to the axis of revolution A54) opposite the first transverse face 56, a cylindrical lateral face 60, and a second through-hole 62, opening at the level of the first and second transverse faces 56 and 58, communicating with the second hole 24 and having an axis coinciding with the axis of revolution A54. The first transverse face 56 has a curvature identical to that of the outer face F16' of the outer skin 16. The second support 54 is positioned so that the second through-hole 62 is substantially coaxial with the second hole 24.

[0048] According to one configuration, the first transverse face 56 includes a cylindrical boss 64, configured to fit into the second orifice 24, having a diameter substantially equal to that of the second orifice 24. This boss 64 allows the second support 54 to be centered relative to the second orifice 24.

[0049] The second support 54 is connected to the outer skin 16 by at least one permanent and watertight connection 66. In one configuration, the second support 54 is connected to the outer skin 16 by a first peripheral weld bead 66 linking the cylindrical side face 60 of the second support 54 and the outer face F16' of the outer skin 16, and by a second peripheral weld bead 66' interposed between the boss 64 and the second opening 24. Of course, other solutions are conceivable for watertightly connecting the second support 54 and the outer skin 16. Alternatively, the second support 54 and the outer skin 16 form a single piece.

[0050] The second through orifice 62 has a first section 62.1 at the level of the first transverse face 56, a counterbore 62.2 at the level of the second transverse face 58, a second section 62.3, between the first section and the counterbore 62.1, 62.2, having a diameter greater than that of the first section 62.1 and less than that of the counterbore 62.2 as well as a transverse bearing face 62.4 connecting the first and second sections 62.1, 62.3.

[0051] The interlayer duct 30 is connected to the second support 54 or to the outer skin 16 by a removable and watertight connection 68 housed in the second section 62.3 of the second through orifice 62. According to one configuration, the interlayer duct 30 comprises a tubular extension 70 which includes a first tubular portion 70.1 cooperating with the second end section 30.2 of the interlayer duct 30, a second tubular portion 70.2 located in the extension of the first tubular portion 70.1 as well as a crown 70.3 projecting from the outer face of the tubular portions 70.1, 70.2 and substantially perpendicular to this outer face.

[0052] According to one arrangement, the first tubular portion 70.1 is fitted inside or outside the second end section 30.2 of the intermediate conduit 30 and connected to the latter by a sealed, peripheral and permanent connection 72 such as a peripheral weld bead for example.

[0053] The crown 70.3 is configured to press against the second support 54, more particularly against its boss 64. To reinforce the seal, the removable and sealed link 68 includes an O-ring 74 interposed between the crown 70.3 and the second support 54.

[0054] The second tubular portion 70.2 is configured to be able to fit at least partially into the second through orifice 62. For this purpose, it has an outside diameter slightly smaller than that of the first section 62.1 of the second through orifice 62 of the second support 54.

[0055] According to one configuration, the detachable link 68 includes a thread 68.1 at the external face of the second tubular portion 70.2 of the tubular extension 70 of the intercalated conduit 30 and a nut 68.2 configured to screw onto the external face of the second tubular portion 70.2 of the tubular extension 70 and bear against the second support 54, in particular the transverse bearing face 62.4. The detachable link includes a system to prevent unintentional unscrewing of the nut 68.2, such as an anti-rotation ring 68.3 for example.

[0056] Of course, the invention is not limited to this embodiment for the detachable and watertight connection 68 linking the intermediate conduit 30 and the second support 54 and / or the outer skin 16. Thus, the intermediate conduit 30 and the tubular extension 70 could form only one and the same piece.

[0057] According to one embodiment, the second plug 28 is in the form of a disc having a first end face 76.1 configured to be pressed against the second transverse face 58 of the second support 54, a second end face 76.2 opposite the first end face 76.1, and a cylindrical lateral face 76.3 connecting the first and second end faces 76.1, 76.2 and having a diameter substantially equal to that of the cylindrical lateral face 60 of the second support 54. To facilitate centering the second plug 28 with respect to the second support 54, the second plug 28 includes a boss 78, projecting from the first end face 76.1, configured to fit without play into the counterbore 62.2 of the second through hole 62 of the second support 54.

[0058] The inspection device includes a removable and watertight connection 80 for linking the second plug 28 and the second support 64. Depending on one configuration, the removable connection includes several screws 80.1 that pass through the second plug 28 and screw into the second support 54. To reinforce the seal between the second plug 28 and the second support 54, the removable and watertight connection 80 includes an O-ring 82 interposed between the counterbore 62.2 of the second support 54 and the boss 78 of the second plug 28.

[0059] Regardless of the embodiment, the first and second orifices 22, 24, the first and second through orifices 40, 62 and the intercalated conduit 30 are sized to allow the passage of an endoscopic camera.

[0060] According to one configuration, the inspection device 20 includes a purge system 84 configured to control the pressure present in the passage area 32.

[0061] In one configuration, the purge system 84 is integral with the second plug 28. It includes a valve 86 having an inlet 86.1 communicating with the passage zone 32 when the second plug 28 is in its first mounted state, and an outlet 86.2 configured to be connected with a vacuum device 88 (visible on the figure 6 ) or sealed with a 90 plug (visible on the figure 2 ). According to one embodiment, the second plug 28 comprises a tubular extension 92, projecting from the second end face 76.2, having a free end 92.1 distant from the second end face 76.2 and a conduit 94 opening at the level of the first end face 76.1 of the second plug 28 and at the level of the free end 92.1 of the tubular extension 92. The conduit 94 has, at the level of the free end 92.1, a threaded end 94.1 allowing the inlet 86.1 of the valve 86 to be screwed on.

[0062] In addition, the valve 86 includes a control 86.3, such as a knob, configured to control the flow of a fluid between the inlet 86.1 and the outlet 86.2 by occupying a closed state or a more or less open state.

[0063] According to one embodiment, the inspection device 20 includes at least one insulator 96 positioned in the passage zone 32. According to one configuration, the insulator 96 comprises several disc-shaped MLI (Multi Layer Insulation) type insulating layers 96.1, each having a diameter equal to or slightly less than that of the intermediate conduit 30. In addition, the insulator 96 includes a tubular insulator 96.2, fitted into the intermediate conduit 30, sandwiched between the insulating layers 96.1 and the second plug 28.

[0064] According to one arrangement, the inspection device 20 includes a movable support 98 to which the insulation 96, more particularly the insulating layers 96.1, is connected, configured to insert the insulation 96 into the passage area 32 or to extract it from it.

[0065] This mobile support 98 has a rod 98.1 onto which the various insulating layers 96.1 are threaded, a base 98.2 attached to one end of the rod 98.1, and a head 98.3 attached to the other end of the rod 98.1. The head 98.3 is connected to the rod 98.1 by a detachable link. For example, the head 98.3 is configured to screw onto the second end of the rod 98.1. When the head 98.3 is detached from the rod 98.1, the insulating layers 96.1 are threaded onto the rod 98.1. Once the insulating layers 96.1 are positioned around the rod 98.1, the head 98.3 is screwed onto the rod 98.1.

[0066] The 98.3 head is configured to ensure a good grip to allow easy handling of the 98 support and the 96 insulation, as well as locking the 96 insulation in vertical translation.

[0067] The inspection device includes a detachable link 100 configured to connect the movable support 98 to the first plug 26 and / or the first support 34. By way of example, the base 98.2 can be clipped onto the first plug 26 and / or screwed onto the first support 34. Of course, the invention is not limited to this embodiment for obtaining the detachable link 100.

[0068] The assembly of a double-walled tank equipped with an inspection device is described with regard to the figures 3 à 6 Initially, as illustrated on the figure 3 Since the inner skin 12 is not positioned within the outer skin 16, the first support 34 is fixed to the inner skin 12, the intermediate conduit 30 is connected to the first support 34, and the first plug 26 is screwed into the first support 34. The fact that the inner skin 12 is not inserted into the outer skin 16 makes the areas where the permanent and watertight connections 41 and 52 are made more accessible. A clamping tool 102 is used to screw the first plug 26 onto the first support 34 to ensure optimal sealing between the first plug 26 and the first support 34. The tubular insulation 31 is positioned around the intermediate conduit 30.

[0069] Following, as illustrated on the figure 4 The intermediate conduit 30 is compressed using a compression tool 104 which cooperates with the first support 34 and compresses the intermediate conduit 30. In the presence of tubular insulation 31, the compression tool 104 cooperates with the tubular insulation 31 and allows its compression simultaneously with that of the tubular conduit 30. Compressing the intermediate conduit 30 and the tubular insulation 30 reduces its length in the radial direction and simplifies the insertion of the inner skin 12 into the outer skin 16.

[0070] After the inner skin 12 is placed inside the outer skin 16, the compression tool 104 is removed. Automatically, the intermediate conduit 30 and the tubular insulation 31 return to their original length, and the second tubular portion 70.2 of the tubular extension 70 of the intermediate conduit 30 partially passes through the second support 54. The removable connection 68 is assembled to link the intermediate conduit 30 and the second support 54, as illustrated in the figure. figure 5 . Next, the mobile support 98 and the insulator 96 are inserted into the passage area 32 and then the second plug 28 is connected to the second support 54 by means of the removable and watertight connection 80.

[0071] Finally, as illustrated on the figure 6 To reduce the pressure in the passage zone 32, the valve 86 is opened and its outlet 86.2 is connected to a vacuum device 88. When the passage zone 32 has a vacuum level substantially equal to that of the intermediate zone 14, on the order of 10-7 to 10-11 bar, the valve 86 is closed and the vacuum device 88 is disconnected from the outlet 86.2. The plug 90 is then positioned to close the outlet 86.2.

[0072] Tank 10 is then ready for use.

[0073] The procedure for using the inspection device 20 to perform an inspection is described with regard to the figures 7 à 10 .

[0074] Initially, as illustrated on the figure 7 , the plug 90 is removed from outlet 86.2 and the valve 86 is opened so that the passage area 32 is at atmospheric pressure.

[0075] Next, the second plug 28 is removed, then the movable support 98 and the insulator 96 are removed from the passage area 32, as illustrated in the figure 8 .

[0076] The first cap 26 is then unscrewed using the tightening tool 102, as illustrated in the figure 9 Finally, an endoscopic camera 106 can be introduced into the reservoir 10 in order to inspect, in particular, the inner skin 12, as illustrated in the figure 10 .

[0077] After inspection, the first plug 26 is screwed back on, the movable support 98 and the insulator 96 are reinserted into the passage area 32, and then the second plug 28 is reinstalled. Finally, the passage area 32 is evacuated, as previously described.

[0078] The inspection device 20 allows for easy inspection of the inside of the tank 10 without the need to dismantle the connection system of the outlet pipe of the tank 10. This inspection device 20 also ensures that the sealing and thermal insulation of the tank 10 are not compromised.

Claims

1. Tank comprising an interior skin (12), an exterior skin (16) and an intercalated zone (14) between the interior and exterior skins (12, 16), the interior and exterior skins (12,16) delimiting an interior zone (Int) in contact with the interior skin (12) and an exterior zone (Ext) in contact with the exterior skin (16), the tank comprising at least one inspection device (20) including: - a first orifice (22) configured to establish communication between the interior zone (Int) and the intercalated zone (14) via the interior skin (12), - a second orifice (24) configured to establish communication between the intercalated zone (14) and the exterior zone (Ext) via the exterior skin (16), the first and second orifices (22, 24) being aligned in a radial direction, - a first plug (26) configured to occupy a mounted first state in which the first plug (26) prevents any flow through the first orifice (22) and a demounted second state in which the first plug (26) enables access through the first orifice (22), - a second plug (28) configured to occupy a mounted first state in which the second plug (28) prevents any flow through the second orifice (24) and a demounted second state in which the second plug (28) enables access through the second orifice (24), - an intercalated pipe (30) positioned in the intercalated zone (14), having a first end section (30.1) connected to the interior skin (12) and communicating with the first orifice (22), a second end section (30.2) connected to the exterior skin (16) and communicating with the second orifice (24), and an intercalated section (30.3) forming a bellows configured to be deformed in the radial direction, the inspection device(20) comprising a permanent sealed connection (52) connecting the intercalated pipe (30) and a first support (34) fastened to the interior skin (12) or the interior skin (12) and a sealed demountable connection (68) connecting the intercalated pipe (30) and second support (54) fastened to the exterior skin (16) or the exterior skin (16), characterized in that the interior wall (12) of the tank (10) has an internal face (F12) oriented toward the interior zone (Int) and an external face (F12') oriented toward the intercalated zone (14) and in that the first support (34) is connected by at least one permanent sealed connection (41) to the interior skin (12) and has a first transverse face (36) pressed against the external face (F12') of the interior skin (12), a second transverse face (38) opposite the first transverse face (36), a lateral surface (42) including at least one section configured to cooperate with the first end section (30.1) of the intercalated pipe (30), and a first through-orifice (40) discharging on the first and second transverse faces (36, 38), communicating with the first orifice (22) and configured to cooperate with the first plug (26).

2. Tank as claimed in the preceding claim characterized in that the inspection device (20) includes insulation (96) positioned in a passage zone (32) delimited by the intercalated pipe (30).

3. Tank as claimed in the preceding claim characterized in that the inspection device (20) includes a mobile support (98) to which the insulation (96) is connected configured to insert the insulation (96) in the passage zone (32) or to extract it therefrom.

4. Tank as claimed in the preceding claim characterized in that the inspection device (20) includes a demountable connection (100) configured to connect the mobile support (98) to the first plug (26) and / or to a first support (34) fastened to the interior skin (12).

5. Tank as claimed in any one of the preceding claims characterized in that the inspection device (20) includes a purging system (84) configured to control the pressure in a passage zone (32) delimited by the intercalated pipe (30) and the first and second plugs (26, 28) in the mounted first state.

6. Tank as claimed in the preceding claim characterized in that the purging system (84) includes a valve (86) having an inlet (86.1) that communicates with the passage zone (32) when the second plug (28) occupies the mounted first state, an outlet (86.2) and a control member (86.3) configured to control a flow of fluid between the inlet (86.1) and the outlet (86.2).

7. Tank as claimed in any one of the preceding claims characterized in that the first through-orifice (40) has a first section (40.1) discharging on the first transverse face (36), a second section (40.2) discharging on the second transverse face (38) which has a diameter greater than that of the first section (40.1), and a transverse bearing face (40.3) connecting the first and second sections (40.1, 40.2), in that the first plug (26) includes a cylindrical body extending between first and second end faces (44.1, 44.2) connected by a lateral face (46) configured to cooperate with the second section (40.2) of the first through-orifice (40) of the first support (34), the first end face (44.1) being oriented toward the transverse bearing face (40.3) of the first through-orifice (40) when the first plug (26) is in the mounted first state, and in that the inspection device (20) includes an annular seal (48) intercalated between the first end face (44.1) of the first plug (26) and the transverse bearing face (40.3) of the first through-orifice (40) of the first support (34).

8. Tank as claimed in the preceding claim characterized in that the second section (40.2) of the first through-orifice (40) is threaded and in that the lateral face (46) of the first plug (26) has a first section adjacent to the first end face (44.1) that has a greater diameter than the first section (40.1) of the first through-orifice (40) and a smaller diameter than the second section (40.2) of the first through-orifice (40) and a second section adjacent to the second end face (44.2), at least partially threaded and configured to be screwed into the second section (40.2) of the first through-orifice (40).

9. Tank as claimed in the preceding claim characterized in that the second section of the lateral face (46) includes an annular groove to enable an element to be clipped on.

10. Tank as claimed in claim 8 or 9 characterized in that the first plug (26) includes an imprint (50) on the second end face (44.2) to enable it to be screwed into the first through-orifice (40).

11. Tank as claimed in any one of preceding claims characterized in that the exterior skin (16) has an internal face (F16) oriented toward the intercalated zone (14) and an external face (F16') oriented toward the exterior zone (Ext) and in that the second support (54) is connected by at least one sealed permanent connection (66) to the exterior skin (16) and has a first transverse face (56) pressed against the external face (F16') of the exterior skin (16), a second transverse face (58) opposite the first transverse face (56), and a second through-orifice (62) discharging on the first and second transverse faces (56, 58) and communicating with the second orifice (24), the second plug (28) being configured to be pressed against the second transverse face (58) and connected to the second support (54) by a sealed demountable connection (80).

12. Tank as claimed in the preceding claim characterized in that the second through-orifice (62) includes a first section (62.1) at the level of the first transverse face (56) and a second section (62.3) having a diameter greater than that of the first section (62.1) configured to accommodate the sealed and demountable connection (68) and a transverse bearing face (62.4) connecting the first and second sections (62.1, 62.3), in that the intercalated pipe (30) has a tubular extension (70) including a tubular portion (70.2) configured to be accommodated at least partially in the second orifice (62), and in that the sealed demountable connection (68) includes a thread (68.1) at the level of the tubular portion (70.2) of the tubular extension (70) of the intercalated pipe (30) and a nut (68.2) configured to be screwed onto the tubular portion (70.2) of the tubular extension (70) and to bear against the transverse bearing face (62.4) of the second support (54).

13. Tank as claimed in the preceding claim characterized in that the tubular extension (70) includes a first tubular portion (70.1) cooperating with the second end section (30.2) of the intercalated pipe (30), a second tubular portion (70.2) cooperating with the nut (68.2) of the sealed demountable connection (68), and a ring (70.3) configured to be pressed against the second support (54), and in that the sealed demountable connection (68) includes a seal (74) intercalated between the ring (70.3) and the second support (54).

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