Cryogenic fluid storage unit and corresponding production method

Abstract

The cryogenic fluid storage unit comprises: an inner tank (3); an outer tank (7); -a proximal suspension (23P) connecting a proximal end (22D) of the inner tank to the outer tank, the proximal suspension comprising an outer tube (25) rigidly attached to the proximal end (22P) of the inner tank, an inner tube (27) arranged in the outer tube and connected to the outer tank, and a stopper (29) connecting the inner tube to the outer tube; the proximal suspension comprises a proximal insulating body (53P) radially interposed between the outer tube and the inner tube, the proximal insulating body comprising an insulating sleeve (57) and at least one blocking element (59) having a central axis (C) and resiliently biasing the sleeve (57) on an inner surface of the outer tube (25) or an outer surface of the inner tube (27).

Description

Technical Field

[0001] The present invention generally relates to a cryogenic fluid storage unit. Background Art

[0002] Such a storage unit typically includes an inner tank that defines an accommodation volume for cryogenic fluid inwardly, and an outer tank in which the inner tank is housed.

[0003] The storage unit further includes a suspension having a proximal suspension that connects the proximal end of the inner tank to the outer tank and a distal suspension that connects the distal end of the inner tank to the outer tank.

[0004] It may be provided that the proximal suspension includes an outer tube rigidly attached to the proximal end of the inner tank, an inner tube disposed in the outer tube and connected to the outer tank, and a plug that connects the inner tube to the outer tube.

[0005] The outer tube has a first end rigidly attached to the peripheral edge of an opening disposed in the proximal end of the inner tank. The outer tube extends inside the inner tank. The outer tube is in contact with the cryogenic fluid stored in the accommodation volume. The plug closes the second end of the outer tube.

[0006] The inner tube has a first end that exits through an opening disposed at the proximal end of the inner tank and a second end directly connected to the plug. The second end is also closed by the plug.

[0007] To limit the radiative heat transfer between the outer tank and the inner tank, a layer of insulating material is placed above the inner tank and completely wraps the inner tank.

[0008] To complete the thermal insulation, it is also necessary to reduce the radiative transfer between the outer tube and the inner tube of the proximal suspension. Mounting an insulator between the two tubes is particularly tricky because the space available for inserting the insulator is extremely limited. Summary of the Invention

[0009] In this context, the present invention aims to provide a cryogenic fluid storage unit in which the insulator of the proximal suspension is particularly good.

[0010] To this end, the present invention relates to a cryogenic fluid storage unit, which includes:

[0011] - an inner tank that defines an accommodation volume for cryogenic fluid inwardly, the inner tank having a proximal end and a distal end opposite to the proximal end;

[0012] - an outer tank in which the inner tank is housed;

[0013] - A suspension, the suspension including a proximal suspension connecting the proximal end of the inner tank to the outer tank, the proximal suspension including an outer tube rigidly attached to the proximal end of the inner tank, an inner tube disposed in the outer tube and connected to the outer tank, and a plug connecting the inner tube to the outer tube;

[0014] The proximal suspension includes a proximal thermal insulator radially interposed between the outer tube and the inner tube, the proximal thermal insulator including a thermal insulation sleeve and at least one interception element, the at least one interception element having a central axis and elastically biasing the sleeve against the inner surface of the outer tube or the outer surface of the inner tube.

[0015] The proximal thermal insulator radially interposed between the outer tube and the inner tube restricts radiative transfer between the outer tube and the inner tube. The proximal thermal insulator is pressed against the outer tube or the inner tube by the interception element.

[0016] Therefore, the proximal insulator is held in place without the risk of the thermal insulation sleeve forming a thermal bridge between the outer tube and the inner tube.

[0017] If the sleeve deforms and has a part contacting the outer tube and a part contacting the inner tube, the sleeve may constitute a thermal bridge. This risk is eliminated by the presence of the interception tube.

[0018] Therefore, the thermal insulator at the proximal suspension is improved.

[0019] The cryogenic fluid storage unit may further have one or more of the following features considered individually or in any technically possible combination:

[0020] - The interception element has a lug facing the plug at one axial end;

[0021] - The interception element has the form of an interception tube having a specific outer surface area, and the interception tube is preferably perforated in its outer surface area in a proportion between 50% and 99%;

[0022] - The interception tube has a slot defined by two opposite axial edges, the slot extending throughout the axial length of the interception tube, the interception tube including a fastener that can be selectively locked or released, and the two axial edges of the interception tube move away from each other when the fastener is released and are attached to each other when the fastener is locked;

[0023] - The outer tube has an inner diameter, the sleeve has a sleeve thickness, the interception tube has a rest diameter at rest when the fastener is released, and twice the sleeve thickness plus the rest diameter of the interception tube is greater than the inner diameter of the outer tube;

[0024] - When the fastener is locked, the interception tube has a reduced diameter greater than the outer diameter of the inner tube, and the sum of the reduced diameter of the interception tube and twice the sleeve thickness is less than the inner diameter of the outer tube;

[0025] - The interception element presses against the radially inner surface of the sleeve, and the protection tube presses against the radially outer surface of the sleeve;

[0026] - The sleeve is disengaged from contact with the inner tube and / or with the plug.

[0027] According to a second aspect, the present invention relates to a method for producing a storage unit having the foregoing characteristics, the method comprising the following steps:

[0028] - Obtaining the inner tank, the inner tube, the outer tube, the plug and the interception tube;

[0029] - Assembling the inner tank, the inner tube, the outer tube and the plug to each other;

[0030] - Fitting the sleeve around the interception tube;

[0031] - Locking the fastener;

[0032] - Inserting the sleeve and the interception tube between the inner tube and the outer tube;

[0033] - Releasing the fastener.

[0034] The production method may further have the following characteristics:

[0035] - In the step of fitting the sleeve around the interception tube, the interception tube is constrained to an intermediate diameter, which is equal to the inner diameter of the outer tube plus twice the sleeve thickness plus or minus 10%. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Other features and advantages of the present invention will become apparent from the following detailed description given in a non-limiting illustrative manner with reference to the accompanying drawings, in which:

[0037] - Figure 1 is an axial sectional view of a cryogenic fluid storage unit;

[0038] - Figure 2 is Figure 1 an enlarged sectional view of the suspension of the proximal end of the inner tank of; and

[0039] - Figure 3 is Figure 2 a perspective view of the interception tube of the thermal insulator of the suspension of. DETAILED DESCRIPTION

[0040] Figure 1The storage unit 1 shown is intended to store cryogenic fluids. Cryogenic fluids are understood to be fluids at very low temperatures, which can be at least partially in a liquid state inside the storage unit.

[0041] This fluid is typically hydrogen. Alternatively, the fluid is helium, nitrogen, natural gas such as methane CH4, air, or any other suitable fluid.

[0042] The storage unit is typically intended to be installed on a vehicle (such as a motor vehicle, a train, a ship, or any other vehicle) having an electric propulsion motor.

[0043] The motor vehicle is, for example, a car, a multi-purpose vehicle, a truck, etc.

[0044] The storage unit 1 is typically designed to supply power to a fuel cell. The fuel cell is configured to generate electricity and supply power to the electric propulsion motor of the vehicle.

[0045] The storage unit 1 includes an inner tank 3 that defines an accommodation volume 5 for the cryogenic fluid, an outer tank 7 in which the inner tank 3 is received, and a suspension 9.

[0046] The suspension 9 is intended to attach the inner tank 3 to the outer tank 7.

[0047] In the example shown, the inner reservoir 3 has a horizontal central axis C.

[0048] The inner reservoir includes a housing 11 that is closed at both axial ends by a bottom 13.

[0049] The housing 11 is cylindrical about the central axis C.

[0050] The outer reservoir 7 also has a horizontal axis.

[0051] The outer reservoir includes a housing 15 that surrounds the housing 11 of the inner tank, and the housing 15 is closed at both ends by a bottom 17 that is placed opposite to the bottom 13 of the inner tank 3.

[0052] The housing 15 is cylindrical about the central axis C.

[0053] The inner tank 3 and the outer tank 7 define an intermediate space 19 therebetween that is maintained at a high vacuum. This vacuum is typically on the order of 10-5 mbar in order to strongly limit convective heat transfer from the outer tank 7 to the inner tank 3.

[0054] An insulator 21 is interposed between the inner reservoir 3 and the outer reservoir 7. The insulator 21 is typically placed on the outer surface of the inner reservoir 3.

[0055] The insulator 21 includes, for example, a plurality of metal sheets stacked on top of each other, with fiber layers interposed therebetween.

[0056] The suspension 9 is arranged such that the entire weight of the inner reservoir 3 is borne by the outer reservoir 7 via the suspension 9.

[0057] The weight of the inner tank 3 is here understood to include the weight of the cryogenic fluid stored in the inner tank 3.

[0058] The acceleration experienced by the inner tank 3 and the cryogenic fluid contained in the inner tank 3 is also transmitted via the suspension 9 to the outer tank 7.

[0059] When the storage unit 1 is installed in a vehicle, these accelerations are caused by a change in the direction of the vehicle, braking applied to the vehicle, acceleration of the vehicle, unevenness or irregularities of the road, or even an impact on the vehicle.

[0060] The inner tank 3 has a proximal end 22P and a distal end 22D opposite the proximal end 22P.

[0061] In the example shown, the proximal end and the distal end correspond to the two bottoms 13 of the inner tank 3.

[0062] The suspension 9 includes a proximal suspension 23P that connects the proximal end 22P of the inner tank 3 to the outer tank 7.

[0063] Similarly, the suspension 9 includes a distal suspension 23D that connects the distal end 22D of the inner tank 3 to the outer tank 7.

[0064] Generally, the proximal suspension 23P and the distal suspension 23D are identical to each other. Only the proximal suspension 23P will be described below.

[0065] As Figure 2 The proximal suspension 23P shown includes an outer tube 25 rigidly attached to the proximal end 22P of the inner tank 3, an inner tube 27 disposed within the outer tube 25 and connected to the outer tank 7, and a plug 29 that connects the inner tube 27 to the outer tube 25.

[0066] The outer tube 25 is generally coaxial with the central axis C.

[0067] This outer tube has a first end 31 rigidly attached to a ring 33 that is itself integral with the edge of an opening 35 disposed at the proximal end 22P of the inner tank 3.

[0068] The outer tube 25 has a second end 36 opposite the first end 31 that is rigidly attached to the plug 29.

[0069] The cross-section of the outer tube 25 perpendicular to the central axis C is generally circular.

[0070] This outer tube has a substantially constant cross-section throughout its axial length.

[0071] The outer tube 25 extends inwardly from the proximal end 22P into the inner tank 3. Thus, the plug 29 is also located inside the inner tank 3.

[0072] The inner tube 27 is coaxial with the central axis C.

[0073] The inner tube has a first end 37 rigidly attached to the ring 39. The ring 39 is connected to the outer tank 7 via the cup-shaped member 41. The ring 39 is rigidly attached to the edge of the opening 43 disposed in the cup-shaped member 41.

[0074] The inner tube 27 has a second end 45 rigidly attached to the plug 29.

[0075] The plug 29 seals both the outer tube 25 and the inner tube 27. The plug includes a solid bottom 47 carrying two concentric annular ribs 49, 51.

[0076] The outer tube 25 is rigidly attached to the radially outer rib 49.

[0077] The inner tube 27 is rigidly attached to the radially inner rib 51.

[0078] As Figure 2 can be shown, the proximal suspension 23P includes a proximal thermal insulator 53P radially interposed between the outer tube 25 and the inner tube 27.

[0079] The proximal thermal insulator 53P slides into the cylindrical gap 55 between the outer tube 25 and the inner tube 27.

[0080] The proximal thermal insulator 53P includes a thermal insulating sleeve 57 and an intercepting element 59.

[0081] The intercepting element 59 elastically biases the sleeve 57 against the inner surface 61 of the outer tube 25.

[0082] The sleeve 57 is tubular and coaxial with the central axis C.

[0083] The sleeve is constructed in substantially the same manner as the thermal insulator 21 assembled on the inner tank 3.

[0084] Thus, the sleeve includes a plurality of metal sheets radially stacked on one another, with fiber layers interposed therebetween.

[0085] The metal layers are substantially cylindrical, coaxial with the central axis C, and radially stacked on top of one another, with fiber layers interposed therebetween.

[0086] Alternatively, the sleeve 57 is obtained by laminating fiber layers on metal sheets and by winding the metal sheets and fiber layers together in a spiral around a mandrel. The metal layer and the fiber layer can be wound from a single roll, or one roll of metal sheets and one roll of fiber layers can be unwound in parallel.

[0087] The metal layer is made of aluminum or an aluminum alloy. Each layer is particularly thin and has a thickness of approximately 7 μm.

[0088] The fibers in the fiber layer are, for example, glass fibers. These fibers are in the form of a paper-like material.

[0089] The total number of radially stacked metal layers and fiber layers is typically between 10 and 40.

[0090] The interception element 59 is preferably an interception tube.

[0091] The interception element 59 is typically coaxial with the central axis C. This interception element bears against the radially inner surface of the sleeve 57.

[0092] The interception element 59 has a substantially circular cross-section that is constant throughout its length perpendicular to its central axis C.

[0093] Figure 3 The interception element 59 is shown in more detail in. The interception element 59 is made of metal, preferably a metal with low or medium thermal conductivity.

[0094] For example, the interception element 59 is made of stainless steel to prevent corrosion.

[0095] For example, the interception element is made of 316L stainless steel.

[0096] The interception tube 59 is perforated to limit conductive heat transfer therein.

[0097] The interception tube has a specific outer surface area and is perforated in 50% to 99% of its outer surface area. The interception element 59 is preferably perforated in 60% to 95% of its outer surface area, and even more preferably in 70% to 90% of its outer surface area.

[0098] The outer surface area is the surface area of the radially outer surface of the interception element 59.

[0099] As Figure 3 shown, the wall of the interception element 59 has a large number of openings 62. The cumulative surface area of the openings 62 is between 50% and 99% of the outer surface area of the interception tube 59.

[0100] In the example shown, the openings 62 are substantially rhombic. Alternatively, these openings are rectangular, circular, or have any other suitable shape.

[0101] The interception element 59 is defined by substantially circular edges 63 at its two axial ends.

[0102] The interception element has lugs 65 at its axial ends that face the plug 29. The lugs 65 point axially from the circular edge 63.

[0103] These lugs point towards the plug 29.

[0104] The sleeve 57 extends continuously around the interception element 59. In other words, the sleeve covers the entire radial outer surface of the interception element 59. The sleeve extends axially from one circular edge 63 to another circular edge. Generally, the sleeve 57 does not axially protrude beyond the circular edge 63 of the interception element 59.

[0105] Therefore, the lugs 65 also axially protrude relative to the sleeve 57.

[0106] Therefore, the lugs 65 prevent any contact between the sleeve 57 and the plug 29.

[0107] This is particularly advantageous because the sleeve 57 is anisotropic. The sleeve has a particularly low thermal conductivity in the radial direction. The thermal conductivity is on the order of 0.02 mW / m.K.

[0108] On the other hand, the axial thermal conductivity of the sleeve is much higher. The axial conductivity is on the order of 6000 mW / m.K. This is because the aluminum foil has a particularly high thermal conductivity.

[0109] Therefore, it is crucial to avoid any axial contact between the sleeve 57 and the plug 29 because the plug 29 is in direct contact with the cryogenic fluid filling the inner tank 3.

[0110] As Figure 3 shown, the interception element 59 has a slot 67 defined by two opposite axial edges 69.

[0111] The slot 67 extends along the entire axial length of the interception element 59. The slot opens at the two circular edges 63 of the interception tube 59.

[0112] The interception element 59 further includes a fastener 71 that can be selectively locked or released.

[0113] When the fastener 71 is released, the two axial edges 69 of the interception element 59 move away from each other.

[0114] These axial edges are spaced apart, as Figure 3 shown.

[0115] Conversely, when the fastener 71 is locked, the two axial edges 69 of the interception element 59 are attached to each other.

[0116] Generally, these axial edges then extend closely adjacent to each other or even against each other.

[0117] Therefore, when the fastener 71 is locked, the interception tube 59 is not prone to radial expansion.

[0118] Conversely, when the fastener 71 is released, the interception tube 59 may expand radially.

[0119] In the example shown, the fastener 71 includes a hook 73 carried by one of the axial edges 69 of the interception element 59 and a tongue 75 arranged in the other axial edge 69 of the interception element 59. In the locked position, the hook 73 engages with the tongue 75. In the released position, the hook 73 does not engage with the tongue 75.

[0120] Alternatively, the fastener 71 can be of any other type and includes, for example, two hooks 73 carried by two opposite axial edges 69 of the interception element 59, and a shaft that can be engaged in and withdrawn from the hooks 73.

[0121] When the fastener 71 is released, the interception element 59 has a rest diameter Dr at rest. "At rest" in this context means in the absence of external constraints.

[0122] When the fastener 71 is released, the interception element 59 is radially elastic. In other words, if the interception element is forced by an external force to a diameter smaller than its rest diameter Dr, it resists the elastic restoring force in the radially expanding direction. If the external force is removed, the interception element elastically returns to its rest diameter Dr.

[0123] Twice the rest diameter Dr of the interception element 59 plus the thickness Em of the sleeve is greater than or equal to the inner diameter Di of the outer tube 25. In other words:

[0124] Dr + 2Em ≥ Di

[0125] This means that when the fastener 71 is released, the interception element 59 will spontaneously press the sleeve 57 against the inner surface of the outer tube 25 due to the selection of its rest diameter Dr.

[0126] According to another aspect, when the fastener 71 is locked, the interception element 59 has a reduced diameter Dd that is greater than the outer diameter De of the inner tube 27. The maximum outer diameter of the inner tube 57 is considered herein. In the example shown, the outer diameter reaches its maximum value at both ends of the inner tube 27.

[0127] Furthermore, twice the thickness Em of the sleeve plus the reduced diameter Dd of the interception element 59 is less than or equal to the inner diameter Di of the outer tube 25. In other words:

[0128] Dd > De and Dd + 2Em ≤ Di

[0129] These conditions reflect the fact that when the fastener 71 is locked, the proximal thermal insulator 53P can axially slide into the gap 55 between the inner tube 27 and the outer tube 25.

[0130] In this case, the diameter of the interception element 59 remains greater than the outer diameter De of the inner tube 27. On the other hand, the reduced diameter Dd is chosen to be small enough so that the proximal thermal insulator 53P does not impede the outer tube 25 when it is inserted into the gap 55.

[0131] To facilitate the axial insertion of the proximal thermal insulator 53P into the gap 55, the protective tube 77 is pressed against the radially outer surface of the sleeve 53.

[0132] The protective tube 77 is made of PTFE or is a metal tube. If the tube 77 remains in place after insertion, the protective tube can be perforated.

[0133] The protective tube has a low coefficient of friction with respect to the material forming the outer tube 25.

[0134] The protective tube is thin and made of a low-rigidity material so as not to impede the expansion of the interception element 59 and the elastic pressing of the sleeve 57 against the inner surface of the outer tube 25.

[0135] The protective tube 77 protects the sleeve 57 and prevents any damage to the sleeve during insertion into the gap 55.

[0136] As shown previously, the sleeve 57 is composed of particularly thin metal sheets and fiber layers, which also have very low mechanical strength. Thus, any physical contact between the sleeve 57 and the outer tube 25 may cause tearing of the outer layer of the sleeve 57 and the formation of bumps on the outer surface of the sleeve 57.

[0137] As Figure 2 shown, after insertion into the gap 55, the sleeve 57 is disengaged from the inner tube 27 and from the plug 29.

[0138] Example embodiments will now be briefly described.

[0139] The outer diameter De of the inner tube 27 is approximately 114.3 millimeters. The inner diameter Di of the outer tube 25 is approximately 149.2 millimeters.

[0140] The sleeve 57 has a thickness Em of approximately 10 millimeters.

[0141] The interception element 59 is a 316L type stainless steel blank, approximately 0.5 millimeters thick. The blank is made of wire mesh. The blank is cut by stamping or die-cutting.

[0142] The blank is then rolled and assumes its rest diameter. The rest diameter Dr is approximately 133 millimeters.

[0143] The width of the slot 67 at rest is approximately 15 millimeters.

[0144] The reduced diameter Dd of the interception element 59 is approximately 118 millimeters.

[0145] A method of manufacturing the aforementioned storage unit 1 will now be described.

[0146] The method includes steps of obtaining the inner tank 3, the inner tube 27, the outer tube 25, the plug 29, and the interception element 59.

[0147] The interception element 59 is obtained from a blank of wire mesh as previously described. The blank is then rolled to a cylindrical shape.

[0148] The method further includes steps of assembling the inner tank 3, the inner tube 27, the outer tube 25, and the plug 29 to each other.

[0149] The method then includes a step of fitting the sleeve 57 around the interception element 59. The method then includes the following steps:

[0150] - Locking the fastener 71;

[0151] - Inserting the sleeve 57 and the interception element 59 between the inner tube 27 and the outer tube 25;

[0152] - Releasing the fastener 71.

[0153] In the assembly step, the interception element 59 is advantageously constrained to an intermediate diameter Dm which is equal to the inner diameter Di of the outer tube 25 plus twice the sleeve thickness Em plus or minus 10%.

[0154] To achieve this, the interception element 59 is mounted on a mandrel and pressed against the mandrel. The mandrel has the aforementioned intermediate diameter Dm. Then the sleeve 57 is positioned around the interception element 59 which is constrained to the intermediate diameter Dm. The sleeve is wound or formed or threaded around the interception element 59.

[0155] In other words, at the assembly step, the sleeve 57 and the interception element 59 substantially have the final diameter which the sleeve and the interception element will assume once they are disposed inside the outer tube 25 against the inner surface of the outer tube 25.

[0156] The sleeve 57 and the interception element 59 are axially inserted through the ring 33 and the first end 31 of the outer tube 25.

[0157] Then the fastener 71 is released by slightly deforming the interception element 59 so as to disengage the hook 73 from the lug 75.

[0158] Once the fastener has been released, the diameter of the interception element 59 elastically expands until the interception element substantially returns to the intermediate diameter Dm.

[0159] The previously disclosed storage unit has several advantages.

[0160] Designing the interception element in the form of a tube makes it easy to assemble the interception element onto the sleeve and ensures that the sleeve is firmly held.

[0161] Since between 50% and 99% of the outer surface area of the interception element is perforated, the conductive heat transfer in the interception element is extremely low.

[0162] The fact that the interception element has a lug at one axial end facing the plug of the plug prevents contact between the sleeve and the plug. This is particularly important for restricting heat transfer in the axial direction through the metal layer constituting the sleeve.

[0163] The fact that the interception element has a slot extending along its entire length and a fastener capable of interlocking the two axial edges defining the slot allows the diameter of the interception element and thus the diameter of the proximal thermal insulator to be temporarily reduced. This makes it easier to axially insert the proximal thermal insulator into the gap between the inner tube and the outer tube. Once the proximal thermal insulator is axially in place, the fastener can be released, allowing the interception element to elastically expand radially and press the sleeve against the inner surface of the outer tube. This is carried out in a particularly convenient manner.

[0164] The risk of interference between the sleeve and the outer tube is reduced, as is the risk of damage to the upper layer of the sleeve.

[0165] The fact that the interception element has a rest diameter at rest when the fastener is released (the rest diameter is selected such that the rest diameter plus twice the thickness of the sleeve is greater than the inner diameter) allows the sleeve to be elastically pressed against the inner surface of the outer tube.

[0166] The fact that the interception element has a reduced diameter greater than the outer diameter of the inner tube when the fastener is locked (the reduced diameter plus twice the sleeve thickness is less than the inner diameter of the outer tube) allows the proximal thermal insulator to be axially inserted between the inner tube and the outer tube, where the risk of the proximal thermal insulator interfering with the outer tube or the inner tube is reduced.

[0167] The fact that the interception element presses against the radially inner surface of the sleeve and the protective tube presses against the radially outer surface of the sleeve allows the radially outer surface of the sleeve to be protected during insertion between the inner tube and the outer tube.

[0168] The fact that the sleeve is disengaged from the inner tube without contacting the plug limits heat transfer.

[0169] The fact that the sleeve is not free in the space between the inner face of the outer tube and the outer face of the inner tube ensures that the sleeve does not move during the entire use of the tank, and in particular ensures that its ends can contact the plug. If the metal parts of the multi-layer insulation were to contact the plug, the insulation performance would be severely affected.

[0170] The storage unit and the production method can take many forms.

[0171] The examples described above include a sleeve elastically pressed against the inner surface of the outer tube by an interception element. In a variant, the sleeve is placed on the outer surface of the inner tube and is elastically biased against this outer surface by the interception element. Thus, the sleeve can be pressed against the outer face of the inner tube of the suspension, where the interception element attaches the multi-layer insulation on the other side. In this case, the interception element has a smaller free diameter and opens to allow insertion. This variant is particularly advantageous because the outer tube of the suspension is at a very low temperature, and thus its radiation amount is very low. However, the inner tube of the suspension is hotter and thus radiates more. Therefore, it is very useful to very quickly limit this radiation by placing the multi-layer insulation on this hot component. The last layer of the insulation is at a temperature much lower than the temperature of the outer surface of the inner tube of the suspension. This lower temperature limits the radiation from this last layer towards the inner surface of the outer tube of the suspension. The heat radiated depends on the temperature to the fourth power.

[0172] In this case, the interception element is arranged on the radially outer surface of the sleeve.

[0173] Generally, the distal suspension includes the same distal insulation as the proximal insulation. Alternatively, the distal insulation is different.

[0174] The interception element is not a tube, but can include, for example, a plurality of rings distributed along the sleeve.

Claims

1. A cryogenic fluid storage unit, the storage unit (1) comprising: - An inner tank (3) that defines internally a volume (5) for containing a cryogenic fluid, the inner tank (3) having a proximal end (22P) and a distal end (22D) opposite the proximal end (22P); - An outer tank (7) in which the inner tank (3) is housed; - A suspension (9), the suspension comprising a proximal suspension (23P) connecting the proximal end (22D) of the inner tank (3) to the outer tank (7), the proximal suspension (23P) comprising an outer tube (25) rigidly attached to the proximal end (22P) of the inner tank (3), an inner tube (27) disposed in the outer tube (25) and connected to the outer tank (7), and a plug (29) connecting the inner tube (27) to the outer tube (25); The proximal suspension (S23P) comprises a proximal thermal insulator (53P) radially interposed between the outer tube (25) and the inner tube (27), the proximal thermal insulator (53P) comprising a thermal insulation sleeve (57) and at least one interception element (59), the at least one interception element having a central axis (C) and elastically biasing the sleeve (57) against the inner surface of the outer tube (25) or the outer surface of the inner tube (27).

2. The cryogenic fluid storage unit according to claim 1, wherein the interception element (59) has a lug (65) facing the plug (29) at an axial end.

3. The cryogenic fluid storage unit according to claim 1 or 2, wherein the interception element (59) is in the form of an interception tube having a specific outer surface area, the interception tube being preferably perforated in 50% to 99% of its outer surface area.

4. The cryogenic fluid storage unit according to claim 3, wherein the interception tube (59) has a slot (67) defined by two opposite axial edges (69), the slot (67) extending throughout the axial length of the interception tube (59), the interception tube (59) comprising a fastener (71) that can be selectively locked or released, the two axial edges (69) of the interception tube (59) moving away from each other when the fastener (71) is released and attaching to each other when the fastener (71) is locked.

5. The cryogenic fluid storage unit according to claim 4, wherein the outer tube (25) has an inner diameter (Di), the sleeve (57) has a sleeve thickness (Em), the interception tube (59) has a rest diameter (Dr) at rest when the fastener (71) is released, and twice the sleeve thickness (Em) plus the rest diameter (Dr) of the interception tube (59) is greater than the inner diameter (Di) of the outer tube (25).

6. The cryogenic fluid storage unit according to claim 5, wherein the intercepting tube (59) has a reduced diameter (Dd) greater than the outer diameter (De) of the inner tube (27) when the fastener (71) is locked, and twice the sum of the reduced diameter (Dd) of the intercepting tube (59) and the sleeve thickness (Em) is less than the inner diameter (Di) of the outer tube (25).

7. The cryogenic fluid storage unit according to any one of the preceding claims, wherein the intercepting element (59) is pressed against the radially inner surface of the sleeve (57), and the protective tube (77) is pressed against the radially outer surface of the sleeve (57).

8. The cryogenic fluid storage unit according to any one of the preceding claims, wherein the sleeve (57) is disengaged from the inner tube (27) and / or from the plug (29).

9. A method for producing a storage unit according to any one of claims 4 to 6, the method comprising the following steps: - obtaining the inner tank (3), the inner tube (27), the outer tube (25), the plug (29) and the intercepting tube (59); - assembling the inner tank (3), the inner tube (27), the outer tube (25) and the plug (29) to each other; - fitting the sleeve (57) around the intercepting tube (59); - locking the fastener (71); - inserting the sleeve (57) and the intercepting tube (59) between the inner tube (27) and the outer tube (25); - releasing the fastener (71).

10. The production method according to claim 9, wherein in the step of fitting the sleeve (57) around the intercepting tube (59), the intercepting tube (59) is constrained to an intermediate diameter (Dm), the intermediate diameter being equal to the inner diameter (Di) of the outer tube (25) plus twice the sleeve thickness (Em) plus or minus 10%.

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