Aviation tank system for storing hydrogen at cryogenic temperatures for transportation by aircraft

Abstract

The present invention provides a removable aviation tank system 30 with cryogenic storage capability for transportation by aircraft. The aviation tank system 30 according to the present invention comprises a forward cryogenic tank 36, an aft cryogenic tank 37 and at least one temporary storage central tank 7 for pressurization of gas supplied by the forward cryogenic tank 36 and the aft cryogenic tank 37.

Description

[Technical field]

[0001] The present invention relates to the aviation industry. [Background technology]

[0002] In the early days of aviation, high-octane gasoline engines were used. After 1945, with the development of jet engines and turbines, kerosene was used. Kerosene has a higher molecular weight, higher energy density, higher efficiency, and lower flammability than gasoline. These fuels are usually stored in tanks located in the wings, at the fuselage-wing joints, or in the tail.

[0003] The drive to reduce carbon dioxide emissions has led to the development of engines with lower fuel consumption. However, as certain technologies (especially blade tip speeds) develop, the effect of reducing carbon dioxide emissions is diminishing. This break with the past is increasingly desirable.

[0004] This led to the development of gas-powered aircraft. Gases with short or no carbon chains can be burned with oxygen when necessary with little or no pollution. On the other hand, H2, O2, C1 and C2 gases are difficult to store and prone to leaks due to their small gas molecules.

[0005] On the ground, such gases are typically stored in pressurized cases (such cases have too much weight, volume, and pressure energy to be carried on an aircraft) or in welded or bonded cryogenic tanks. Cryogenic storage of such gases has a limited storage time proportional to the amount stored.

[0006] Furthermore, hydrogen, methane, ethane, ethylene, acetylene and oxygen stored in liquid form cannot be used in internal or external combustion engines or fuel cells - they require a gaseous state for ultimate consumption.

[0007] There is therefore a need to store propellant gas on-board aircraft for consumption while applying aviation maintenance know-how and avoiding the need for new standardization. Indeed, establishing new standards is a lengthy process that risks delaying the market launch of gas-powered aircraft. Learning new maintenance know-how also takes time and is costly, which may lead to resistance. Summary of the Invention

[0008] The present invention proposes a removable aviation tank arrangement with cryogenic storage capacity for transportation by aircraft. The aviation tank arrangement according to the invention comprises a front cryogenic tank, an aft cryogenic tank and at least one central tank for temporary storage for the pressure build-up of gas supplied by the front and aft cryogenic tanks. The invention allows the aviation tank arrangement to have an elongated shape so that it can be installed on an aircraft with a high ratio of stored energy to the size of the aviation tank arrangement. Storage and gasification are carried out separately and close to each other. The above-mentioned "detachable" means that the aviation tank arrangement can be installed and removed from the aircraft very quickly, with or without tools, on the runway of the airport. The installation of the aviation tank arrangement is advantageously of the "plug and play" type.

[0009] Unlike the aerospace industry, where parts are used for only a few seconds or even tens of seconds, the aviation industry requires parts to have long life spans of tens of thousands of hours and tens of thousands of cycles.

[0010] In one embodiment, each of the front and rear cryogenic tanks has a convex outer shape, each of the front and rear cryogenic tanks comprises an inner casing defining a storage chamber, an outer casing housing the inner casing, an insulating chamber defined between the inner and outer casings, a removable manifold sealingly penetrating the outer and inner casings, and a pipe through which gas is supplied by the manifold, and the central tank for temporary storage has a quasi-(near) toroidal or quasi-(near) annular shape, which facilitates the utilization of the available space.

[0011] In one embodiment, each of the front and rear cryogenic tanks is vacuum insulated against conduction, convection, and radiation, thereby reducing natural evaporation.

[0012] In one embodiment, the aviation tank arrangement comprises a forward cryogenic tank and an aft cryogenic tank having an elongated shape along a common axis, thereby providing an elongated profile for the aviation tank arrangement.

[0013] In one embodiment, the aviation tank system comprises at least two spherical forward cryogenic tanks and at least two spherical aft cryogenic tanks, which promotes the utilization of the available space relative to the contained weight.

[0014] In one embodiment, the aviation tank system comprises a number of temporary storage tanks each arranged between two cryogenic tanks (between the two forward cryogenic tanks and between the two aft cryogenic tanks), thereby increasing the temporary storage capacity.

[0015] In one embodiment, the central temporary storage tank forms a gasification member, to which an upstream valve and a downstream valve are provided. The upstream valve is provided for liquid flow during a filling phase of the central temporary storage tank and is closed outside the filling phase. The downstream valve is provided for gas flow during a draining phase of the central temporary storage tank and is closed outside the draining phase. The upstream and downstream valves are closed during the gasification phase. Such a system ensures that the volume of the temporary storage tank gives the aircraft the required autonomy, regardless of the state of the cryogenic tank. The temporary storage tank may be configured to accommodate gas pressures of several hundred bar, while the gas consumers are supplied with the desired gas pressure.

[0016] In one embodiment, the upstream valve and the downstream valve are controlled in an on-off manner. Such valves are highly reliable.

[0017] In one embodiment, the aviation tank arrangement comprises a compressor arranged downstream of the downstream valve and a pressure regulator arranged downstream of the downstream valve, the compressor being activated at the end of the discharge phase to bring the pressure in the central temporary storage tank to a value lower than the minimum of the pressures in the front and rear cryogenic tanks, the pressure regulator being activated at the beginning of the discharge phase to bring the pressure of gas at the outlet of the central temporary storage tank to a value lower than the pressure in the central temporary storage tank. The discharge from the temporary storage tank can be sufficient to increase the amount of gas available to the gas consumer and to bring the pressure in the temporary storage tank at the end of the discharge to a value lower than the pressure in the current cryogenic tank designated for filling. The filling of the temporary storage tank is carried out by the operation of the cryogenic valve under the influence of a pressure difference. The omission of a cryogenic pump reduces weight and reduces the risk of accidents.

[0018] In one embodiment, each of the forward and aft cryogenic tanks is configured to accommodate a working pressure of less than 8 bar and the central temporary storage tank is configured to accommodate a working pressure of more than 500 bar, thereby reducing the empty weight of the cryogenic tanks.

[0019] Other features and advantages of the present invention will become apparent from the following detailed description and accompanying drawings, in which: [Brief description of the drawings]

[0020] [Figure 1] 1 is a side view showing a schematic diagram of an aviation cryogenic tank apparatus according to one embodiment of the present invention; [Diagram 2] 1 is a longitudinal sectional view showing an aviation cryogenic tank device according to an embodiment of the present invention; [Diagram 3] FIG. 1 is an exploded view showing a schematic diagram of an aviation cryogenic tank apparatus according to an embodiment of the present invention. [Figure 4] FIG. 2 is a longitudinal sectional view showing an aviation cryogenic tank device according to another embodiment of the present invention. [Diagram 5] FIG. 2 is a longitudinal sectional view showing an aviation cryogenic tank device according to another embodiment of the present invention. [Figure 6] FIG. 1 is a diagram illustrating a schematic diagram of a distribution circuit according to an embodiment of the present invention.

[0021] The accompanying drawings may serve not only to supplement the invention but also to contribute to its definition, if desired. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The aviation gas storage device is configured to be transported by an aircraft (e.g., airplane, drone, helicopter, etc.). The aviation gas storage device contains a liquid and supplies the gas. In other words, the gas is stored in a cryogenic tank in a liquid state at a very low temperature. The cryogenic tank cannot withstand high pressures, especially above 10 bar.

[0023] Furthermore, gas stored in a liquid state cannot be used in internal or external combustion engines or fuel cells, as final consumption requires gas within the temperature and pressure ranges specified by the manufacturer of the consumer component.

[0024] The gases stored are selected from hydrogen, methane, ethane, ethylene, acetylene, and oxygen.

[0025] Applicants also consider that gasification is a rapid phenomenon that occurs at high altitudes in ambient air at -55° C. For example, gaseous hydrogen at 0° C. and 1 atmosphere pressure has about 800 times lower density, i.e., about 800 times larger volume, than liquid hydrogen at -253° C.

[0026] Furthermore, aircraft maintenance regulations require that most parts of an aircraft can be removed and repaired or replaced. This allows an aircraft to land anywhere that is compatible with the weight and landing requirements of the aircraft (airfields for airplanes, airfields for helicopters) without having to have maintenance equipment specific to the aircraft model. If damage is detected, the aircraft is configured so that it can be repaired permanently or temporarily, or disassembled to replace or repair the faulty parts, according to the manufacturer's manuals and documents approved by the aviation safety authorities. It is desirable that aircraft parts can be easily accessed by maintenance personnel. It is desirable that parts to be replaced are configured as small as possible to facilitate handling and transportation. It is desirable that parts to be repaired can be repaired by proven tools and methods commonly used in the aviation industry.

[0027] Aircraft are inspected, for example daily or weekly, and therefore remain on the ground for a period of time inversely proportional to the inspection frequency.

[0028] The applicant has identified a need for storage using aviation cryogenic tanks on board aircraft, particularly for the storage of hydrogen, methane, ethane, ethylene, acetylene or oxygen.

[0029] From another perspective, airplanes are now subject to regulations that stipulate the maximum distance from the runway according to ETOPS certification, which varies depending on the type of airplane.

[0030] In order to provide a high level of safety and to ensure that this safety is perceived by users, the Applicant has recognized that it is necessary to fly even if the cryogenic tank is damaged and the gases contained therein are released into the atmosphere.

[0031] The aviation tank system (aviation fuel tank system) 30 is intended to meet the complex requirements analyzed above by the applicant of the present application.

[0032] The aviation tank system 30 with cryogenic storage is adapted to be transported on an aircraft. The aviation tank system 30 is filled with liquid and supplies gas under a selected pressure. In other words, the fuel or oxidizer is stored in liquid state at very low temperatures in the cryogenic tank. The cryogenic tank cannot withstand high pressures, especially above 10 bar.

[0033] The aviation tank device 30 has a shape of a fuel tank. The aviation tank device 30 is provided with an attachment mechanism 31 for quickly attaching it to the wing of an aircraft.

[0034] In the embodiment shown in Figs. 1 to 3, the aviation tank device 30 has an elongated shape. The aviation tank device 30 comprises a central body 32, a front end 33 and an aft end 34. The front end 33 and the aft end 34 each have a shell to ensure an aerodynamic shape. The central body 32 comprises one or more generally cylindrical sections. In this embodiment, three sections are provided: a central section 35, a forward section and an aft section. The shells of the front end 33 and the aft end 34 and the sections of the central body 32 are detachable. The shells of the front end 33 and the aft end 34 and the sections of the central body 32 provide mechanical protection against impacts, in particular bird strikes at the front end and impacts during handling.

[0035] The mounting mechanism 31 is designed for rapid assembly and disassembly. This allows the aviation tank device 30 to be mounted on the aircraft in a short time (particularly a few minutes or tens of minutes) simultaneously with other work being performed on the runway. The short time is shorter than the minimum layover time. The mounting mechanism 31 is provided approximately in the center of the length of the aviation tank device 30 or at or near the center of gravity of the aviation tank device 30 in the length direction. In this embodiment, the mounting mechanism 31 is integrated with the center section 35 of the center body 32. The mounting mechanism 31 is provided with a quick connector for the gas line. The center section 35 supports the forward section and the aft section. The forward section supports the forward end 33 and the aft section supports the aft end 34.

[0036] As shown in FIG. 1, the center body 32, the forward end 33, and the aft end 34 each have an exterior surface (particularly an aerodynamic surface) adapted to the air flow at the speed of the aircraft. These exterior surfaces form a fairing. Joints may be provided between the center body 32 and the forward end 33 and between the center body 32 and the aft end 34. Vents are provided in the center body 32, the forward end 33, and / or the aft end 34 for pressure balance and ventilation, thereby preventing condensation and frost.

[0037] The central body 32 supports components disposed within and at its ends. The central body 32 may include at least one layer of material that absorbs shock and vibration. The central body 32 acts as a shock absorber to limit stress on the attachment mechanism 31 and other components of the apparatus described below. The central body 32 forms a free-standing fairing.

[0038] The aviation tank system 30 includes a forward cryogenic tank 36 and an aft cryogenic tank 37. The center section 35 supports the forward cryogenic tank 36 and the aft cryogenic tank 37.

[0039] The forward and aft cryogenic tanks 36, 37 are mounted inside a section of the center body 32. The forward and aft cryogenic tanks 36, 37 have a generally similar configuration, but may have slightly different shapes to maximize the use of available space. The forward and aft cryogenic tanks 36, 37 are mounted along the entire length of the aviation tank arrangement 30 (from one end of the length to the other). In the illustrated example, the forward and aft cryogenic tanks 36, 37 are aligned along the longitudinal axis, although this feature is optional.

[0040] The front cryogenic tank 36 and the rear cryogenic tank 37 may have an elongated shape along a common axis or along two axes. The front cryogenic tank 36 and the rear cryogenic tank 37 may each have a convexly curved front portion, a convexly curved rear portion, and a cylindrical center portion of revolution.

[0041] The forward section of the center body 32 covers substantially the entire forward cryogenic tank 36. The aft section of the center body 32 covers substantially the entire aft cryogenic tank 37. The central section 35 of the center body 32 substantially covers the aft end of the forward cryogenic tank 36, the forward end of the aft cryogenic tank 37, and a central space 38. The central space 38 has a generally annular shape. The central space 38 is at atmospheric pressure. The central space 38 is configured to be ventilated.

[0042] The aviation tank system 30 comprises at least one central tank 7 for temporary storage. In the illustrated example, two central tanks 7 are shown. These central tanks 7 are installed in parallel. The central tanks 7 are managed by a distribution circuit (regulation circuit) 1 shown in FIG. 6. The central tank 7 is alternately filled with liquid from at least one of the front cryogenic tank 36 and the rear cryogenic tank 37, and after gasification, gas is discharged from the central tank 7. The two central tanks 7 are operated alternately so that one is filled and the other is empty during most of the operating time. However, it may be set so that the two central tanks 7 take off with full.

[0043] Each central tank 7 forms a gasifier (gasification means). Each central tank 7 forms a heat exchanger. Each central tank 7 has at least one inlet for the cryogenic liquid and at least one outlet for the gas. The central tank 7 is not provided with insulation. The central tank 7 consists of a simple casing. The central tank 7 is made of metal and / or composite material. The central tank 7 is made entirely or partly of an electrically conductive material. The central tank 7 is resistant to cryogenic temperatures. The central tank 7 is resistant to high operating pressures compared to the front and rear cryogenic tanks 36 and 37, which are at low pressures. The central tank 7 has a short shelf life compared to the front and rear cryogenic tanks 36 and 37, which have a long shelf life.

[0044] The central tank 7 is mounted in the central space 38, for example on the side opposite the mounting mechanism 31. In the embodiment of Figure 2, the central tank 7 has a cylindrical shape with a vertical axis and rounded ends.

[0045] The central space 38 is compact, limiting the length of the liquid and gas lines, and optimizing the weight of the device.

[0046] In the embodiment shown in FIG. 4, the aviation tank arrangement 30 comprises two front cryogenic tanks 36 and two rear cryogenic tanks 37. The front cryogenic tanks 36 and the rear cryogenic tanks 37 are each spherical. The front cryogenic tanks 36 and the rear cryogenic tanks 37 are arranged in a row in the illustrated example, but this feature is optional. The shape of the temporary storage central tank 7 is annular, in particular toroidal. Furthermore, temporary storage cryogenic tanks 39 are arranged between the two front cryogenic tanks 36 and between the two rear cryogenic tanks 37, respectively, as additional temporary storage tanks (buffer tanks). The shape of the temporary storage cryogenic tanks 39 is annular, in particular toroidal.

[0047] Each cryogenic tank (forward cryogenic tank 36, aft cryogenic tank 37, and temporary storage cryogenic tank 39) is insulated to accommodate liquid fuel or oxidizer at −253° C. Each cryogenic tank (forward cryogenic tank 36, aft cryogenic tank 37, and temporary storage cryogenic tank 39) can withstand a maximum operating pressure of approximately 6 to 10 bar.

[0048] In the embodiment shown in Fig. 5, a number of temporary storage cryogenic tanks (additional buffer tanks) 39 are arranged in the shape of a regular polygon between the two front cryogenic tanks 36. Each temporary storage cryogenic tank 39 has a cylindrical body and rounded ends. The axes of the bodies of the multiple temporary storage cryogenic tanks 39 are arranged, for example, to define a hexagon.

[0049] Between the two rear cryogenic tanks 37, a number of temporary storage cryogenic tanks (additional buffer tanks) 39 are arranged parallel to one another. Each temporary storage cryogenic tank 39 has a cylindrical body and rounded ends. The longitudinal axis of the aviation tank arrangement 30 and the axes of the temporary storage cryogenic tanks 39 are arranged parallel to one another. In a cross-sectional view, the axes of the bodies of the temporary storage cryogenic tanks 39 are arranged to define the vertices of a regular polygon. The temporary storage cryogenic tanks 39 are arranged like the chambers of a barrel.

[0050] 5 shows two embodiments simultaneously for the sake of simplicity, specifically a polygonal embodiment at the front of the aviation tank arrangement 30 and a parallel embodiment at the rear of the aviation tank arrangement 30. In practice, the aviation tank arrangement 30 only has one of these embodiments (either the embodiment in which all the temporary storage cryogenic tanks 39 are arranged in a polygonal shape, or the embodiment in which all the temporary storage cryogenic tanks 39 are arranged parallel to each other). In either embodiment, the configuration of the temporary storage cryogenic tanks 39 is very robust due to its shape adapted to high pressures and manufacturing constraints.

[0051] In one embodiment, at least one temporary storage cryogenic tank 39 is provided with a cylindrical body and rounded ends.

[0052] [Gas distribution circuit]

[0053] The distribution circuit 1 will be described with reference to FIG.

[0054] The distribution circuit 1 for an aircraft is supplied with fuel by cryogenic tanks 36, 37 for supplying gas to one or more gas consumers of the aircraft. At the outlet of each cryogenic tank 36, 37 a flow meter 22 is arranged.

[0055] Each cryogenic tank 36, 37 is fitted with an outlet pipe 4. It should be noted that the terms "upstream" and "downstream" refer to the direction of flow of fluids, liquids or gases during normal operation.

[0056] The distribution circuit 1 comprises a first valve 11 for each cryogenic tank 36, 37. The first valve 11 is attached to the outlet pipe 4. The first valve 11 is switchably controlled between an open position and a closed position. The intermediate positions of the first valve 11 are dynamic in the sense that the first valve 11 passes through said intermediate positions during its movement. In other words, the first valve 11 is configured to be on-off controlled. The first valve 11 may be arranged immediately downstream of the flow meter 22.

[0057] The first valves 11 can be in communication with a cryogenic distributor 5. The cryogenic distributor 5 may comprise a common pipe 6 connecting the outlets of a number of the first valves 11. The cryogenic distributor 5 is cryogenic in the sense that liquid fuel and / or oxidant pass through it.

[0058] The cryogenic distributor 5 has a plurality of outlets, specifically, for example, three outlets. A second valve 12 is attached to each outlet of the cryogenic distributor 5. The second valve 12 is switchably controlled between an open position and a closed position. The intermediate position of the second valve 12 is dynamic in the sense that the second valve 12 passes through the intermediate position during movement. In other words, the second valve 12 is configured to be controlled to be on and off. In the illustrated example, three second valves 12 are provided.

[0059] The central tank 7 is mounted downstream of each second valve 12. In this embodiment, three central tanks 7 are provided. Each central tank 7 also functions as a gasifier (gasification means). No insulation is required. Each central tank 7 receives liquid and supplies gas downstream. In each central tank 7, a pressure build-up phase, i.e. a gasification phase, occurs between filling and discharging. Each central tank 7 can withstand a maximum operating pressure of about 300 to 1000 bar. Each central tank 7 is configured to operate in a temperature range of -253°C to +60°C. In some operating phases, the central tank 7 is in a gas-liquid two-phase state, and in other operating phases, it is in a gas single-phase state. Each central tank 7 may be equipped with a heating element (heater) 8.

[0060] A third valve 13 for supplying gas is provided downstream of each central tank 7, and a pressure regulator 9 is provided downstream of the third valve 13. The pressure regulator 9 reduces the pressure to supply gas at a consumption pressure specified by the manufacturer of the gas consuming part 3. The pressure regulator 9 operates when the pressure in the central tank 7 is higher than the consumption pressure, and does not operate otherwise. The consumption pressure is lower than the maximum pressure of the central tank 7. The consumption pressure is independent of the maximum pressure of the cryogenic tanks 36, 37. The third valve 13 is configured to be controlled to be on and off.

[0061] A controllable fourth valve 14 may be provided downstream of each pressure regulator 9. The fourth valve 14 is arranged to be controlled to be on and off.

[0062] The fourth valve 14 (i.e. pressure regulator 9) can be in communication with a manifold 10 depending on the selected option. The manifold 10 may consist of a single conduit connecting the outlets of multiple fourth valves 14 (i.e. pressure regulators 9). Gas flows through the manifold 10. The manifold 10 is connected downstream to supply lines (supply pipes) 23 to the gas consumers 3. Typically, one supply line 23 is provided per gas consumer 3. Each supply line 23 may be provided with a controllable supply valve 24. The supply valves 24 have a variable flow rate.

[0063] The distribution circuit 1 comprises at least one compressor 20 connected to a manifold 10. Usually, two compressors 20 are provided in parallel for redundancy. The compressors 20 are of the electric type. The compressors 20 may be provided with a controllable upstream valve. The compressors 20 feed gas into the manifold 10. In particular, in the case of one gas consumer 3, the manifold 10 consists of one pipe (conduit).

[0064] A fifth valve 15 for supplying gas is provided downstream of each central tank 7, and a second manifold is provided downstream of the fifth valve 15. The second manifold is connected to a compressor 20. The fifth valve 15 can separate the central tank 7 from the compressor 20. The fifth valve 15 is controllable. The fifth valve 15 is configured to be on / off controlled.

[0065] The compressor 20 increases the pressure so as to supply gas at a pressure equal to the consumption pressure specified by the manufacturer of the gas consumers 3, which is lower than the maximum pressure of the central tank 7. The compressor 20 takes gas from the central tank 7 at a pressure lower than the consumption pressure so that it can be supplied to the manifold 10 and the gas consumers 3. As the central tank 7 becomes more completely emptied, this results in an increase in the autonomy (supply range) provided by the gas contained in it, or a decrease in the volume of the central tank 7.

[0066] Once the central tank 7 is sufficiently emptied so that its internal pressure is lower than the pressure in one of the cryogenic tanks, the pressure difference during filling after emptying allows liquid to be transferred from the cryogenic tanks to the central tank 7. This draws liquid in the cryogenic tanks into the central tank 7 until pressure equilibrium is reached. This allows the elimination of a cryogenic pump, thereby reducing weight and energy consumption.

[0067] The distribution circuit 1 provides a combination of individual states for each cryogenic tank, for each central tank 7 and for each gas consumer 3. Several gas consumers 3 can be in operation at the same time. In normal mode, one cryogenic tank is emptied while the others are closed without being activated. However, in certain circumstances, specific modes can be provided in which several cryogenic tanks are emptied, for example to reduce their pressure. The central tank 7 has a filling mode, a gasification mode, a gas storage mode and an emptied mode.

[0068] When one cryogenic tank is being drained, the corresponding first valve 11 is open and the other first valve 11 is closed. When one gas consumer 3 is being supplied with gas, the corresponding supply valve 24 is open.

[0069] When one central tank 7 is in the filling mode, the second valve 12 connected to said central tank 7 is open and at least one first valve 11 is open. The other second valves 12 are closed except when two central tanks 7 are filled simultaneously. The third valve 13 connected to said central tank 7 is closed. The fifth valve connected to said central tank 7 is closed.

[0070] When one central tank 7 is in gasification mode, the second valve 12 connected to this central tank 7, the third valve 13 connected to this central tank 7 and the fifth valve 15 connected to this central tank 7 are closed. The gasification mode lasts for a short time, especially if the ambient atmosphere is warm and / or the central tank 7 is heated.

[0071] When one central tank 7 is in the discharge mode, the second valve 12 connected to that central tank 7 is closed. At the beginning of the discharge mode, the pressure in the central tank 7 is higher than the consumption pressure. The third valve 13 connected to that central tank 7 is open, the corresponding fourth valve 14 is open, and the fifth valve connected to the central tank 7 is closed. The gas is reduced in pressure regulator 9 and supplied to manifold 10 at the consumption pressure. The gas is then consumed by gas consumer 3.

[0072] At any given time, of the three central tanks 7, one central tank 7 is in the fill mode, another central tank 7 is in the gasification mode and then in the storage mode, and the remaining central tank 7 is in the discharge mode. Due to the different durations of the modes, it is also possible that two central tanks 7 are in the fill mode and the remaining central tank 7 is in the discharge mode, and it is also possible that two central tanks 7 are in the discharge mode and the remaining central tank 7 is in the fill mode. It is also possible that two central tanks 7 are in the storage mode and the remaining central tank 7 is in the discharge mode, and it is also possible that two central tanks 7 are in the discharge mode and the remaining central tank 7 is in the storage mode.

[0073] In this embodiment, a flow meter 22 is arranged at the outlet of each liquid fuel source (oxidizer source), which provides sufficiently accurate information about the amount of liquid being supplied to the central tank 7 as described above.

[0074] In this embodiment, the distribution circuit 1 comprises a control unit 25 which receives external commands, for example from an external gas consumer 3 of the aviation tank device 30 or from a central control unit of the aircraft, and liquid flow rate data from the flow meter 22. The control unit 25 generates and sends commands to the above-mentioned controllable valves (the first, second, third, fourth and fifth valves as well as the supply valve 24). The commands may be commands to "open" or to "close". The control unit 25 manages the combination of the individual states.

[0075] Alternatively, the first valve 11 may be replaced by at least one multi-way valve having multiple inlets and one outlet, in which case it is advantageous to provide a multi-way valve with a mixing position, in particular at least one position for simultaneously draining two or more cryogenic tanks to reduce pressure while preventing losses to the atmosphere.

[0076] Alternatively, the second valve 12 may be replaced by at least one multi-way valve having one inlet and multiple outlets, one for each central tank 7. The multi-way valve forms a distributor.

[0077] Alternatively, the multiple pressure regulators 9 may be replaced by a single pressure regulator 9 with which the third valve 13 can communicate. In this case, the third valve 13 may be replaced by at least one multi-way valve having multiple inlets and one outlet to the pressure regulator 9. The multiple fourth valves 14 are thus replaced by a single uncontrolled fourth valve 14 where appropriate.

[0078] Alternatively, the fifth valve 15 may be replaced by at least one multi-way valve having multiple inlets (one inlet for each central tank 7) and one outlet to one or more compressors 20. The multi-way valve forms a manifold 10.

[0079] Since the cryogenic tank is subject to evaporation of liquid, a gas collection circuit may be provided at the top of the cryogenic tank. The gas collection circuit may be activated when a threshold pressure is exceeded via a calibrated pressure valve. The gas collection circuit comprises a compressor for reinjecting gas downstream (e.g. between the fifth valve 15 and the compressor 20).

[0080] Optionally, additional flow meters may be placed at the inlet of each buffer tank, providing redundancy in liquid flow measurement.

Claims

1. A removable aviation tank device (30) with cryogenic storage capabilities for transportation by aircraft, comprising: a forward cryogenic tank (36); an aft cryogenic tank (37); at least one central tank (7) for temporary storage for the pressure build-up of gas supplied by the front cryogenic tank (36) and the rear cryogenic tank (37); An aviation tank device comprising:

2. each of the front cryogenic tank (36) and the rear cryogenic tank (37) has a convex profile; Each of the front cryogenic tank (36) and the rear cryogenic tank (37) comprises: an inner casing defining a storage chamber; an outer casing that houses the inner casing; an insulating chamber defined between the inner casing and the outer casing; a removable manifold that passes through the outer casing and the inner casing in a sealed state; a pipe to which gas is supplied by the manifold; the central tank (7) for temporary storage has a semi-annular or semi-annular shape, An aviation tank system as claimed in claim 1.

3. Each of the front cryogenic tank (36) and the rear cryogenic tank (37) is insulated under vacuum against conduction, convection, and radiation. An aviation tank apparatus as claimed in claim 1 or 2.

4. The front cryogenic tank (36) and the rear cryogenic tank (37) have an elongated shape along a common axis. An aviation tank apparatus according to any one of claims 1 to 3.

5. at least two spherical front cryogenic tanks (36) and at least two spherical rear cryogenic tanks (37), An aviation tank apparatus according to any one of claims 1 to 3.

6. a plurality of temporary storage tanks (39) disposed between the two front cryogenic tanks (36) and between the two rear cryogenic tanks (37), An aviation tank apparatus according to any one of claims 1 to 5.

7. The temporary storage central tank (7) constitutes a gasification means, For the central tank (7) for temporary storage, an upstream valve (12) arranged to open to allow liquid to flow during the filling stage of the central temporary storage tank (7) and to close outside said filling stage; a downstream valve (13, 15) adapted to open to allow gas flow during the discharge phase of the central tank (7) for temporary storage and to close at other times, The upstream valve (12) and the downstream valve (13, 15) are arranged to be closed during the gasification stage. An aviation tank apparatus according to any one of claims 1 to 6.

8. The upstream valve (12) and the downstream valve (13, 15) are on / off controlled. An aviation tank system as claimed in claim 7.

9. a compressor (20) arranged downstream of the downstream valve (15); and a pressure regulator (9) arranged downstream of the downstream valve (13), said compressor (20) is configured to operate in such a way that, at the end of the discharge phase, the pressure in the central temporary storage tank (7) is lower than the minimum of the pressures in the front cryogenic tank (36) and the rear cryogenic tank (37); the pressure regulator (9) is adapted to operate so that, at the start of the discharge phase, the pressure of the gas at the outlet of the central temporary storage tank (7) is lower than the pressure in the central temporary storage tank (7); An aviation tank apparatus according to any one of claims 1 to 8.

10. each of the front cryogenic tank (36) and the rear cryogenic tank (37) is adapted for a working pressure of less than 8 bar; said central tank for temporary storage (7) is adapted to accommodate a working pressure of more than 500 bar; An aviation tank apparatus according to any one of claims 1 to 9.

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