Tank comprising internal and external enclosures as well as at least one duct passing through said enclosures and along a curved path between said enclosures

Abstract

The invention relates to a tank comprising an outer casing (32), an inner casing (34) positioned within the outer casing (32), and at least one conduit (46) passing through first and second walls (42.1, 42.2) respectively integral with the outer and inner casings (32, 34). The tank (30) comprises, for each conduit (46), first and second rigid connections linking the conduit (46) to the first and second walls (42.1, 42.2), respectively. Each conduit (46) includes an intermediate section (52), located between the first and second walls (42.1, 42.2), which has a curved axis (A46) such that the intermediate section (52) has an excess length between said first and second walls (42.1, 42.2).

Description

[0001] The present application relates to a tank comprising internal and external enclosures as well as at least one conduit passing through said enclosures.

[0002] Such a reservoir is known from US7344045 B2.

[0003] According to an embodiment visible on the figure 1 , a hydrogen tank 10 comprises an external enclosure 12, an internal enclosure 14 positioned in the external enclosure 12, thermal insulation between the external and internal enclosures 12, 14 and two diametrically opposed connecting systems 16, 16' connecting the external and internal enclosures 12, 14. In operation, due to the temperature and pressure of storage of the hydrogen in the cryogenic state, the internal enclosure 14 may, depending on the situation, contract or expand more than the external enclosure 12. Consequently, at least one of the two connecting systems 16' is configured to allow movement of the internal enclosure 14 relative to the external enclosure 12 in a direction of movement. According to one arrangement, the first connecting system 16 (the one on the left in the figure 1 ) is substantially rigid and does not allow any relative movement between the external and internal enclosures 12, 14 while a second connecting system 16' (the one on the right on the figure 1 ) allows relative movement between the external and internal enclosures 12, 14.

[0004] According to an embodiment visible on the figure 2 , the first connection system 16 comprises a tubular interface 18 passing through the external and internal enclosures 12, 14 and having a first end 18.1 opening outside the external tank 12 and a second end 18.2 opening inside the internal tank 14, each of the external and internal enclosures 12, 14 comprising a through hole 12.1, 14.1 to allow the passage of the tubular interface 18. The first connection system 16 comprises a first rigid connection 20 connecting the tubular interface 18 and the external enclosure 12 as well as a second rigid connection 20' connecting the tubular interface 18 and the internal enclosure 14. According to one configuration, one of the first and second connections 20, 20' comprises at least one flange comprising a first wing pressed against the external or internal enclosure 12, 14 and connected to the latter as well as a second wing pressed against the tubular interface 18 and connected to the latter.In addition, the first connection system 16 comprises a first closure plate 22.1 closing the first end 18.1 of the tubular interface 18 as well as a second closure plate 22.2 closing the second end 18.2 of the tubular interface 18.

[0005] The hydrogen tank 10 comprises several conduits 24, 24' which pass through the first and second closure plates 22.1, 22.2 and each comprise a first end 24.1, 24.1' opening into the internal enclosure 14. All these conduits 24, 24' are rectilinear between the first and second closure plates 22.1, 22.2.

[0006] Each of the first and second closure plates 22.1, 22.2 comprises, for each conduit 24, 24', an orifice 26 to allow the conduit 24, 24' to pass through said first or second closure plate 22.1, 22.2. At each orifice 26, each conduit 24, 24' is connected to the first or second closure plate 22.1, 22.2 by a weld bead 28 which connects the conduit 24, 24' to the first or second closure plate 22.1, 22.2 in a sealed manner around the entire perimeter of the conduit 24, 24'.

[0007] In one embodiment, the materials of the different elements (enclosures, conduits, closing plates, connection systems) may be different: for example metallic / composite.

[0008] In operation, taking into account: the pressure in the internal enclosure 14, the difference in thermal expansion between the materials of the conduits 24, 24' and of the connection system 16, the very significant temperature difference between on the one hand the external enclosure 12 and the first closing plate 22.1 and on the other hand the internal enclosure 14 and the second closing plate 22.2, the conduits 24, 24', the welding beads 28 as well as the internal and external enclosures are subjected to significant stresses which can damage them. STATEMENT OF THE INVENTION:

[0009] The present invention aims to overcome all or part of the drawbacks of the prior art. To this end, the subject of the invention is a tank comprising an external enclosure, an internal enclosure positioned in the external enclosure, first and second connecting systems connecting the external and internal enclosures, a first wall integral with or forming part of the external enclosure, a second wall integral with or forming part of the internal enclosure and at least one conduit passing through the first and second walls. In addition, the first and second walls comprise, for each conduit, respectively first and second orifices to allow the conduit to pass through them; the tank comprising, for each conduit, first and second rigid connections connecting the conduit and respectively the first and second walls, each conduit comprising an intermediate section located between the first and second walls.

[0010] According to the invention, the intermediate section has a curved axis such that the intermediate section has an excess length between said first and second walls.

[0011] The excess length of the intermediate section makes it possible to compensate for a dimensional variation between the first and second walls and to limit the stresses on the first and second connections in order to reduce the risks of damage to the conduits and said first and second connections.

[0012] According to another characteristic, the intermediate section has an axis which follows a trajectory in the form of a circular helix.

[0013] According to another characteristic, the first and second walls are substantially parallel to each other and angularly offset by approximately 180°.

[0014] According to another characteristic, the tank comprises several conduits passing through the first and second walls and comprising intermediate sections which follow trajectories in the form of a circular helix having approximately the same helix axis. According to another characteristic, the first connection system comprises: a tubular interface passing through the external and internal enclosures, connected to the latter and having a first end opening outside the external enclosure and a second end opening inside the internal enclosure, a first closing plate closing the first end of the tubular interface and forming the first wall, a second closing plate closing the second end of the tubular interface and forming the second wall.

[0015] The invention also relates to an aircraft comprising at least one tank according to one of the preceding characteristics.

[0016] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which: There figure 1 is a longitudinal section of a tank illustrating an embodiment of the prior art, The figure 2 is a longitudinal section of a connection system, connecting external and internal enclosures of the tank visible on the figure 1 , illustrating an embodiment of the prior art, The figure 3 is a longitudinal section of a connecting system, connecting external and internal enclosures of a tank, illustrating an embodiment of the invention, The figure 4 is a perspective view of a connecting system, connecting external and internal enclosures of a tank, illustrating an embodiment of the invention, The figure 5 is a front view of a first closure plate illustrating an embodiment of the invention, The figure 6 is a front view of a second closure plate illustrating an embodiment of the invention.

[0017] According to an embodiment visible on the figures 3 And 4 , a tank 30 comprises an external enclosure 32, an internal enclosure 34 positioned in the external enclosure 32 as well as two diametrically opposed connection systems 36, connecting the external and internal enclosures 32, 34. According to one configuration, the tank 30 may comprise thermal insulation between the external and internal enclosures 32, 34.

[0018] According to one arrangement, the first connecting system 36 is substantially rigid while the second connecting system (not shown) allows relative movement between the external and internal enclosures 32, 34. The second connecting system is configured to allow relative movement between the external and internal enclosures 32, 34, oriented in a longitudinal direction.

[0019] According to one application, an aircraft comprises at least one tank 30 used to store a fluid in a cryogenic state, such as hydrogen. Of course, the invention is not limited to this application.

[0020] The first connecting system 36 comprises a tubular interface 38 passing through the external and internal enclosures 32, 34, connected to the latter and having a first end 38.1 opening outside the external enclosure 32 as well as a second end 38.2 opening inside the internal enclosure 34, each of the external and internal enclosures 32, 34 comprising a through hole 32.1, 34.1 to allow the passage of the tubular interface 38. The tubular interface 38 has an axis of revolution A38 parallel to the longitudinal direction.

[0021] According to one configuration, the first connecting system 36 comprises, for the internal enclosure 34, two L-shaped flanges 40, 40' positioned on either side of the internal enclosure 34, each flange 40, 40' comprising a first wing 40.1, 40.1' pressed against the internal enclosure 34 and connected to the latter as well as a second wing 40.2, 40.2' pressed against the tubular interface 38 and connected to the latter. The first connecting system 36 also comprises, for the external enclosure 32, a flange 40 positioned outside the external enclosure 32, comprising a first wing 40.1 pressed against the external enclosure 32 and connected to the latter as well as a second wing 40.2 pressed against the tubular interface 38 and connected to the latter. Of course, the invention is not limited to this configuration for the connections between the tubular interface 38 and the external and internal enclosures 32, 34.

[0022] The first connecting system 36 comprises a first closing plate 42.1 closing the first end 38.1 of the tubular interface 38 and a second closing plate 42.2 closing the second end 38.2 of the tubular interface 38. According to one configuration, the tubular interface 38 comprises a first collar 44.1 at its first end 38.1 and a second collar 44.2 at its second end 38.2, each of the first and second collars 44.1, 44.2 having a contact face F44.1, F44.2, positioned in a transverse plane perpendicular to the axis of revolution A38, against which the corresponding closing plate 42.1, 42.2 is pressed. Of course, the invention is not limited to this embodiment for the tubular interface 38.

[0023] The hydrogen tank 30 comprises at least one conduit 46 which passes through the first and second closure plates 42.1, 42.2 and has a first end 46.1 opening outside the external enclosure 32 as well as a second end 46.2 opening into the internal enclosure 32.

[0024] For each conduit 46, the first closure plate 42.1 comprises a first orifice 48.1 to allow the conduit 46 to pass through said first closure plate 42.1. In addition, the reservoir 30 comprises a first connection 50.1 connecting the conduit 46 and the first closure plate 42.1.

[0025] For each conduit 46, the second closure plate 42.2 comprises a second orifice 48.2 to allow the conduit 46 to pass through said second closure plate 42.2. In addition, the reservoir 30 comprises a second connection 50.2 connecting the conduit 46 and the second closure plate 42.2.

[0026] The first and second connections 50.1, 50.2 are rigid connections. Each of them is a sealed connection ensuring a fluid seal between the conduit 46 and the first or second closure plate 42.1, 42.2. For example, each of the first and second connections 50.1, 50.2 comprises at least one weld bead surrounding the conduit 46 and ensuring a seal between the latter and the closure plate 42.1, 42.2. Of course, the invention is not limited to this embodiment for the first and second rigid connections 50.1, 50.2. For example, the first or second connection 50.1, 50.2 could be in the form of a flange.

[0027] The tubular interface 38 and the closure plates 42.1, 42.2 are not further described because they may be identical to those of the prior art.

[0028] Each conduit 46 comprises an intermediate section 52 located between the first and second closing plates 42.1, 42.2.

[0029] According to a characteristic of the invention, the intermediate section 52 has a curved axis A46. Thus, unlike the prior art, the axis A46 is not rectilinear between the first and second closure plates 42.1, 42.2 so that the intermediate section 52 of the conduit 46 has an excess length between said first and second closure plates 42.1, 42.2. This excess length corresponds to the difference in length between, on the one hand, the length of the intermediate section 52 considered along its curved axis A46 and, on the other hand, the distance between the closure plates 42.1 and 42.2 considered along the axis of revolution A38.

[0030] In operation, the outer enclosure 34 and the first closure plate 42.1 are in contact with an environment at room temperature while the inner enclosure 34, the second closure plate 42.2 and the section of the conduit 46 located in the inner enclosure 34 are in contact with a fluid at a cryogenic temperature, significantly lower than the room temperature. This temperature difference causes deformations of unequal values ​​for at least two elements among the inner and outer enclosures 32, 34, the conduit 46 as well as the first and second closure plates 42.1, 42.2. This tends to modify the spacing between the first and second closure plates 42.1, 42.2 at the first and second orifices 48.1, 48.2 and consequently to generate significant stresses in at least one of the aforementioned elements.The excess length of the intermediate section 52 of the conduit 46 makes it possible to compensate for this dimensional variation between the first and second closure plates 42.1, 42.2, to limit the stresses on the first and second connections 50.1, 50.2 and to reduce the risks of damage to said first and second connections 50.1, 50.2.

[0031] According to one configuration, the axis A46 of the intermediate section 52 follows a trajectory in the form of a circular helix at least between the first and second closure plates 42.1, 42.2. According to one arrangement, the first and second closure plates 42.1, 42.2 are substantially parallel to each other and angularly offset by approximately 180°. Consequently, if the first orifice 48.1 of the first closure plate 42.1 is located at 6 o'clock, as illustrated in the figure 5 , the second hole 48.2 of the second closing plate 42.1 is located at 12 o'clock, as illustrated in the figure 6 .

[0032] According to one embodiment, the tank 30 comprises several conduits 46, 46', 46" which pass through the first and second closure plates 42.1, 42.2, each of them comprising an intermediate section 52, 52', 52" which has a curved axis A46, A46', A46" . According to a configuration visible on the figure 4 , all the intermediate sections 52, 52', 52" follow trajectories in the form of a circular helix having approximately the same helix axis, at least between the first and second closing plates 42.1, 42.2.

[0033] Of course, the invention is not limited to the embodiments previously described. The first and second closure plates 42.1, 42.2 could be positioned in line with the walls of the external and internal enclosures 32, 34 respectively. Whatever the embodiment, the tank 30 comprises a first wall 42.1 integral with or forming part of the external enclosure 32, a second wall 42.2 integral with or forming part of the internal enclosure 34 as well as at least one conduit 46 passing through the first and second walls 42.1, 42.2. For each conduit 46, the first and second walls 42.1, 42.2 respectively comprise first and second orifices 48.1, 48.2 to allow the conduit 46 to pass through the first and second walls 42.1, 42.2. In addition, the reservoir 30 comprises, for each conduit 46, first and second rigid connections 50.1, 50.2 connecting the conduit 46 and respectively the first and second walls 42.1, 42.2.

Claims

1. Tank comprising an outer enclosure (32), an inner enclosure (34) positioned in the outer enclosure (32), first and second connection systems (36) connecting the outer and inner enclosures (32, 34), a first wall (42.1) fastened to or forming part of the outer enclosure (32), a second wall (42.2) fastened to or forming part of the inner enclosure (34), and at least one duct (46) passing through the first and second walls (42.1, 42.2); the first and second walls (42.1, 42.2) comprising, for each duct (46), respectively first and second orifices (48.1, 48.2) to allow the duct (46) to pass through them; the tank (30) comprising, for each duct (46), first and second rigid connections (50.1, 50.2) connecting the duct (46) and respectively the first and second walls (42.1, 42.2); each duct (46) comprising an intermediate segment (52) situated between the first and second walls (42.1, 42.2); the intermediate segment (52) having a curved axis (A46) such that the intermediate segment (52) has an excess length between said first and second walls (42.1, 42.2), characterized in that the intermediate segment (52) has an axis (A46) which follows a trajectory in the form of a circular helix.

2. Tank according to the preceding claim, characterized in that the first and second walls (42.1, 42.2) are substantially parallel to each other and angularly offset by about 180°.

3. Tank according to either of the preceding claims, characterized in that the tank comprises a plurality of ducts (46, 46', 46'') passing through the first and second walls (42.1, 42.2) and comprising intermediate segments (52, 52', 52'') which follow trajectories in the form of a circular helix having approximately the same helix axis.

4. Tank according to one of the preceding claims, characterized in that the first connection system comprises: - a tubular interface (38) passing through the outer and inner enclosures (32, 34), connected thereto and having a first end (38.1) opening out to the outside of the outer enclosure (32), and a second end (38.2) opening out to the inside of the inner enclosure (34), - a first closure plate closing the first end (38.1) of the tubular interface (38) and forming the first wall (42.1), - a second closure plate closing the second end (38.2) of the tubular interface (38) and forming the second wall (42.2).

5. Aircraft comprising at least one tank according to one of the preceding claims.

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