Aviation Gas Distribution Equipment

Abstract

The present invention relates to an aviation gas distribution device 1 for distributing gas between at least one liquefied gas source 2 and at least one gas consumer 3 in an aircraft, comprising at least one on-off controlled first valve 11 provided at the outlet of each liquefied gas source 2, a cryogenic distributor 5 connected to each first valve 11 for supplying liquid, a plurality of on-off controlled second valves 12 connected in parallel to the cryogenic distributor 5, a two-phase buffer tank 7 provided for supplying liquid via each second valve 12 and for supplying gas, a third valve 13 controllably provided at the outlet of each buffer tank 7 for supplying gas, a pressure reducing valve 9 provided at the outlet of the third valve 13, and a manifold 10 provided for supplying the gas supplied via the pressure reducing valve 9 to at least one gas consumer 3.

Description

[Technical field]

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

[0002] In the aviation industry, high-octane gasoline engines were used in the early days. After 1945, with the development of jet engines and turbines, kerosene came to be 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, hydrogen, methane, ethane, ethylene, acetylene, and oxygen are typically stored in containers under very high pressure (such containers have too much volume and pressure energy to be loaded onto aircraft) or in welded and / or bonded cryogenic tanks. Cryogenic storage has a limited storage time proportional to the amount stored.

[0006] Furthermore, gas stored in a liquid state cannot be used in internal combustion engines, external combustion engines, or fuel cells, as final consumption requires gas at a temperature and pressure range specified by the fuel consuming part manufacturer.

[0007] Thus, a need has arisen for gas to be stored on-board the aircraft for consumption on board the aircraft. Summary of the Invention

[0008] The present invention provides an aviation gas distribution device for distributing gas between at least one liquefied gas source and at least one gas consumer in an aircraft. The aviation gas distribution device according to the invention comprises at least one on-off controlled first valve at the outlet of each of the liquefied gas sources, a cryogenic distributor connected to each of the first valves for the supply of liquid, a number of on-off controlled second valves connected in parallel to the cryogenic distributor, a two-phase buffer tank (a buffer tank for temporarily storing two-phase fuel of gas and liquid) arranged to supply liquid via each of the second valves and to supply gas, a third valve controllably arranged at the outlet of each of the buffer tanks for the supply of gas, a pressure reducing valve at the outlet of the third valve, and a manifold arranged to supply the gas supplied via the pressure reducing valve to the at least one gas consumer. According to the present invention, the aviation gas distribution device can provide the aircraft with the required autonomy independent of the state of the liquefied gas source via the volumes in the multiple buffer tanks. The buffer tank may be configured to accommodate gas pressures of several hundred bar, so that a desired gas pressure can be supplied to the gas consumer.

[0009] Unlike the space field, where a cryogenic valve does not need to be closed again once it has been used, in the present invention a valve, for example a solenoid valve, is provided that can be opened and closed.

[0010] In one embodiment, the aviation gas distribution device comprises a fourth valve controllably arranged at the outlet of each of the pressure reducing valves to supply gas to any one of the gas consumers (e.g. engines or auxiliary devices for generating electrical energy on board the aircraft) which may be supplied with gas from any one of the buffer tanks.

[0011] In one embodiment, the aviation gas distribution device comprises at least one compressor supplied with gas from at least one of the buffer tanks and at least one fifth valve controllably arranged between the compressor and the buffer tank. Gas can be sufficiently discharged from the buffer tank to increase the amount of gas available to the gas consumers and such that the pressure in the buffer tank at the end of the discharge is lower at this point than the normal pressure of the cryogenic tank designated for filling. The normal pressure in the cryogenic tank is equal to the pressure in the cryogenic distributor when the corresponding first valve is open and, if necessary, the other first valve is closed. The buffer tank is then filled with gas by operating the cryogenic valve under the influence of a pressure difference. The omission of a cryogenic pump reduces weight and the risk of accidents.

[0012] In one embodiment, the aviation gas distribution device comprises a control unit for controlling the at least one first valve for sequential filling and sequential draining of the buffer tanks by pressure difference. The sequential operation allows the number of cryogenic tanks and the number of buffer tanks to be independent of each other. At least one cryogenic tank is provided. At least two, preferably three, buffer tanks are provided.

[0013] When two buffer tanks are provided, one buffer tank is in the discharging process and the other buffer tank is in the filling process or in the gasification process by heating the gas.

[0014] If more than two buffer tanks are provided, the first one is in the process of being discharged, the second one is in the process of being filled, and the third one is in the process of being gasified by heating the gas or is already filled with gas at a given pressure. The time required for gasification depends inter alia on the amount of liquid pumped into the buffer tank, the external temperature, which may be in the range of -55°C (at high altitude) to +60°C (on the ground), and on the aircraft speed. The duration of gasification and the amount of liquid pumped into the buffer tanks may be subject to estimated predictions.

[0015] During gasification, if the corresponding buffer tank exceeds the maximum pressure, the control unit may request a switchover to vent the excess pressure from the buffer tank and temporarily suspend venting from the other buffer tank, and then resume previous operation at the detected excess pressure.

[0016] In one embodiment, the control unit controls the third valve to allow gas flow, first by pressure difference and then by compressor operation, for the discharge of one of the buffer tanks, until the pressure in the buffer tank is lower than the pressure in the cryogenic distributor, the operating time of the compressor being limited, which leads to energy savings.

[0017] In one embodiment, the at least one first valve and the second valve are cryogenic. Other valves may pass gas at less cold temperatures (e.g., about -55°C at high altitudes).

[0018] In one embodiment, the aviation gas distribution system comprises a flow meter arranged at the outlet of each of the liquefied gas sources. Measuring the flow rate of liquid makes it possible to manage the opening times of the first and second valves, as well as the aviation gas distribution system, to deliver the required amount of gas.

[0019] In one embodiment, it is preferred that a further flow meter is disposed at the inlet of the buffer tank.

[0020] An assembly according to an embodiment includes an aviation gas distribution apparatus configured as described above and at least one single source of cryogenic liquefied gas. When one cryogenic tank is in the process of being discharged for filling the buffer tank, the other cryogenic tank may be configured not to be activated. In the event of excessive pressure in the cryogenic tank, priority may be given to discharging to the aviation gas distribution apparatus.

[0021] In one embodiment, an aviation gas distribution method for distributing gas between at least one liquefied gas source and at least one gas consumer in an aircraft comprises: a filling step of filling one of at least two buffer tanks with liquefied gas via at least one on-off controlled first valve provided at an outlet of each of the liquefied gas sources, a cryogenic distributor connected to each of the first valves so as to supply liquid, and one of a plurality of on-off controlled second valves connected in parallel to the cryogenic distributor, wherein the second valve connected to one of the buffer tanks is open, the other second valve is closed, and a third valve controllably provided at the outlet of one of the buffer tanks is closed; and a draining step of the buffer tank, wherein the second valve is closed, the third valve is open, and the gas supplied to the at least one gas consumer flows via a pressure reducing valve provided at the outlet of the third valve. The use of an on-off controlled valve allows the amount of liquid passing through the valve to be controlled by the amount of time the valve is open.

[0022] In one embodiment, in normal operation, the first buffer tank is in the process of being filled with liquid by pressure balance through at least one of the first valve and the second valve corresponding to the first buffer tank (filling process) with the third valve corresponding to the first buffer tank closed, and the second buffer tank is in the process of supplying pressurized gas (draining process) with the second valve corresponding to the second buffer tank closed and the third valve corresponding to the second buffer tank open. Such a mode is adapted for two buffer tanks.

[0023] In one embodiment, in the normal operation described above, the third buffer tank is in the process of gasifying with the second valve corresponding to the third buffer tank closed and the third valve corresponding to the third buffer tank closed. Such a mode is adapted for more than two buffer tanks.

[0024] In one embodiment, the draining step comprises a first sub-step of draining gas from the buffer tank by means of the pressure reducing valve so as to reduce the pressure of the gas to the pressure required by the gas consumer, and a second sub-step subsequent to the first sub-step of draining gas from the buffer tank with the assistance of a pump so as to reduce the pressure of the gas to the pressure required by the gas consumer and to reduce the pressure in the buffer tank at the end of the draining step to a value lower than the pressure present in the cryogenic distributor, thereby obtaining a more complete draining of the buffer tank.

[0025] In one embodiment, the capacity of the buffer tanks is calculated to ensure the flight range of the aircraft according to current standards in the event of an accident affecting the energy reserves (particularly in the event of an accident affecting one of the two buffer tanks and in the event of an accident affecting two of the three buffer tanks).

[0026] 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]

[0027] [Figure 1] FIG. 1 shows a schematic diagram of an apparatus according to one embodiment of the invention with two cryogenic tanks and three buffer tanks. [Diagram 2] FIG. 1 shows a schematic diagram of an apparatus according to one embodiment of the invention with one cryogenic tank and three buffer tanks. [Diagram 3] FIG. 1 shows a schematic diagram of an apparatus according to one embodiment of the invention with one cryogenic tank and three buffer tanks. [Figure 4] FIG. 1 shows a schematic diagram of an apparatus according to one embodiment of the invention with two cryogenic tanks and three buffer tanks. [Diagram 5] FIG. 1 shows a schematic diagram of an apparatus according to one embodiment of the invention with one cryogenic tank and two buffer tanks.

[0028] 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

[0029] The aviation gas distribution device is configured to be mounted on an aircraft (e.g., airplane, drone, helicopter, etc.). The aviation gas distribution device is supplied with a liquid, and the aviation gas distribution device supplies the gas at a selected pressure. In other words, the fuel or oxidizer is stored in a liquid state at a very low temperature in a cryogenic tank. For example, gaseous hydrogen at 0° C. and 1 atmosphere has about 800 times lower density, i.e. about 800 times larger volume, than liquid hydrogen at −253° C. Cryogenic tanks are not configured to withstand high pressures, especially above 10 bar.

[0030] The gases stored are selected from hydrogen, methane, ethane, ethylene, acetylene, and oxygen.

[0031] 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 field.

[0032] 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.

[0033] Aviation gas distribution equipment is therefore subject to the requirements set forth above.

[0034] Applicant has recognized a need to distribute gas from aviation cryogenic tanks, whether the tanks are structurally connected to the aircraft structure, installed within the aircraft, or carried by the aircraft.

[0035] From another perspective, aircraft are now subject to regulations that stipulate the maximum distance from the runway in flight hours according to ETOPS certification, which varies depending on the type of aircraft.

[0036] 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.

[0037] The aviation storage system (aviation tank system) is intended to meet the complex requirements analysed above by the applicant.

[0038] As shown in Fig. 1, an aviation gas distribution device 1 installed in an aircraft is supplied with liquefied gas from a liquefied gas source 2, and supplies the gas to one or more gas consumers 3. Two gas consumers 3 (e.g., two engines and an electric energy generator or an air heating device) are shown in Fig. 1. A flow meter 22 is arranged at the outlet of each liquefied gas source 2.

[0039] The liquefied gas source 2 consists of two cryogenic tanks arranged in parallel, each equipped with an outlet conduit 4. Note that the terms "upstream" and "downstream" refer to the direction of flow of fluids, liquids and gases during normal operation.

[0040] Each cryogenic tank is insulated to store purified gas (e.g., liquid hydrogen at -253°C). Each cryogenic tank is constructed to withstand a maximum operating pressure of approximately 6 to 10 bar.

[0041] The aviation gas distribution device 1 comprises a first valve 11 for each cryogenic tank (liquefied gas source 2). The first valve 11 is attached to the outlet conduit 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 that the first valve 11 passes through said intermediate positions during movement. In other words, the first valve 11 is configured for on-off control. The first valve 11 may be arranged immediately downstream of a flow meter 22. Optionally, the flow meter 22 may be arranged downstream of the first valve 11.

[0042] The first valve 11 can be in communication with a cryogenic distributor 5. The cryogenic distributor 5 may include a common pipe 6 connecting the outlets of a number of the first valves 11. The cryogenic distributor 5 is cryogenic in that it passes liquefied gas.

[0043] 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 that the second valve 12 passes through the intermediate position during movement. In other words, the second valve 12 is configured to be of an on-off control type. In the illustrated example, three second valves 12 are provided.

[0044] A buffer tank (buffer tank, temporary storage tank) 7 is attached downstream of each second valve 12. In this embodiment, three buffer tanks 7 are provided. Each buffer tank 7 also functions as a gasifier. No insulation is required. Each buffer tank 7 receives liquid and supplies gas downstream. In each buffer tank 7, a pressure increase step, i.e., a gasification step, occurs between filling and discharging. Each buffer tank 7 can withstand a maximum operating pressure of about 300 to 1000 bar. Each buffer tank 7 is configured to operate in a temperature range of -253°C to +60°C. In some operating steps, the buffer tank 7 is in a gas-liquid two-phase state, and in other operating steps, it is in a gas single-phase state. Each buffer tank 7 may be equipped with a heating element (heater) 8.

[0045] A third valve 13 for supplying gas is provided downstream of each buffer tank 7, and a pressure reducing valve 9 is provided downstream of the third valve 13. The pressure reducing valve 9 reduces the pressure to supply gas at a consumption pressure specified by the manufacturer of the gas consuming part 3. The pressure reducing valve 9 operates when the pressure in the buffer tank 7 is higher than the consumption pressure, and does not operate otherwise. The consumption pressure is lower than the maximum pressure of the buffer tank 7. The consumption pressure is independent of the maximum pressure of the cryogenic tank. The third valve 13 is configured as an on-off control type.

[0046] A controllable fourth valve 14 may be provided downstream of each pressure reducing valve 9. The fourth valve 14 is configured to be of an on-off control type.

[0047] The fourth valve 14 (i.e. pressure reducing valve 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 several fourth valves 14 (i.e. pressure reducing valves 9). The manifold 10 may allow gas to pass through. The manifold 10 is connected downstream to supply conduits 23 to the gas consumers 3. Typically, one supply conduit 23 is provided per gas consumer 3. Each supply conduit 23 may be provided with a controllable supply valve 24. The supply valves 24 have a variable flow rate.

[0048] The aviation gas distribution device 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).

[0049] A fifth valve 15 for supplying gas is provided downstream of each buffer 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 buffer tank 7 from the compressor 20. The fifth valve 15 is controllable. The fifth valve 15 is configured as an on-off control type.

[0050] 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 consumer 3, which is lower than the maximum pressure of the buffer tank 7. The compressor 20 takes gas from the buffer tank 7 at a pressure lower than the consumption pressure so that it can be supplied to the manifold 10 and the gas consumer 3. As the buffer tank 7 becomes more completely emptied, this results in an increase in the autonomy (supply range) provided by the gas contained in the buffer tank 7 or a decrease in the volume of the buffer tank 7.

[0051] Once the buffer tank 7 is sufficiently emptied such that the internal pressure of the buffer tank 7 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 tank to the buffer tank 7. This draws liquid from the cryogenic tank into the buffer tank 7 until pressure equilibrium is reached. The elimination of a cryogenic pump is possible, thus reducing weight and energy consumption.

[0052] The aviation gas distribution device 1 provides a combination of individual states for each cryogenic tank, for each buffer tank 7 and for each gas consumer 3. Several gas consumers 3 can be operated simultaneously. In normal mode, one cryogenic tank is emptied while the other tanks are closed without being operated. However, in certain circumstances, a specific mode can be provided in which several cryogenic tanks are emptied, for example to reduce the pressure in the several cryogenic tanks. The buffer tank 7 has a filling mode, a gasification mode, a gas storage mode and an emptied mode.

[0053] 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.

[0054] When one buffer tank 7 is in the filling mode, the second valve 12 connected to said buffer tank 7 is open and at least one first valve 11 is open. The other second valves 12 are closed except when two buffer tanks 7 are filling simultaneously. The third valve 13 connected to said buffer tank 7 is closed. The fifth valve connected to said buffer tank 7 is closed.

[0055] When a buffer tank 7 is in gasification mode, the second valve 12 connected to this buffer tank 7, the third valve 13 connected to this buffer tank 7 and the fifth valve 15 connected to this buffer tank 7 are closed. The gasification mode lasts for a short time, especially if the ambient atmosphere is warm and / or the buffer tank 7 is heated.

[0056] When one buffer tank 7 is in the discharge mode, the second valve 12 connected to that buffer tank 7 is closed. At the beginning of the discharge mode, the pressure in the buffer tank 7 is higher than the consumption pressure. The third valve 13 connected to that buffer tank 7 is open, the corresponding fourth valve 14 is open, and the fifth valve connected to the buffer tank 7 is closed. The gas is depressurized in the pressure reducing valve 9 and supplied to the manifold 10 at the consumption pressure. The gas is then consumed by the gas consumer 3.

[0057] At any given time, of the three buffer tanks 7, one buffer tank 7 is in the filling mode, another buffer tank 7 is in the gasification mode and then in the storage mode, and the remaining buffer tank 7 is in the discharge mode. Due to the different durations of the modes, it is also possible that two buffer tanks 7 are in the filling mode and the remaining buffer tank 7 is in the discharge mode, and it is also possible that two buffer tanks 7 are in the discharge mode and the remaining buffer tank 7 is in the filling mode. It is also possible that two buffer tanks 7 are in the storage mode and the remaining buffer tank 7 is in the discharge mode, and it is also possible that two buffer tanks 7 are in the discharge mode and the remaining buffer tank 7 is in the storage mode.

[0058] In this embodiment, a flow meter 22 is arranged at the outlet of each liquefied gas source 2. The flow meter 22 makes it possible to know with sufficient accuracy the amount of liquid supplied to the buffer tank 7 as described above.

[0059] In this embodiment, the aviation gas distribution device 1 comprises a control unit 25 which receives external commands, for example from the gas consumer 3 or the aircraft's central control unit, 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.

[0060] In a variant, the first valve 11 may be replaced by at least one multi-way valve having several 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 simultaneous discharge from two or more liquefied gas sources 2 to reduce pressure while preventing losses to the atmosphere.

[0061] In a variant, the second valve 12 may be replaced by at least one multi-way valve having one inlet and several outlets, one for each buffer tank 7. The multi-way valve forms a distributor.

[0062] In a variant, the multiple pressure reducing valves 9 may be replaced by a single pressure reducing valve 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 reducing valve 9. The multiple fourth valves 14 are thus replaced by a single fourth valve 14 which is not controlled where appropriate.

[0063] In a variant, the fifth valve 15 may be replaced by at least one multi-way valve having several inlets (one inlet for each buffer tank 7) and one outlet to one or several compressors 20. The multi-way valve forms a manifold 10.

[0064] In the embodiment shown in Fig. 2, the aviation gas distribution device 1 is associated with a liquefied gas source 2 for filling three buffer tanks 7 supplying gas to two gas consumers 3. The first valve 11 may be omitted, since a second valve 12 is sufficient to direct the flow of liquid from the liquefied gas source 2 to one buffer tank 7.

[0065] Furthermore, only one pressure reducing valve 9 is provided. Also, only one fourth valve 14 is provided. The pressure reducing valve 9 is connected downstream of the third valve 13 (three in the example of FIG. 2). Thereby, the pressure reducing valve 9 receives pressurized gas from the buffer tank 7 corresponding to the open third valve 13. This configuration is similarly applied to the embodiment shown in FIG. 5 (embodiment in which two buffer tanks 7 are provided instead of three). The provision of a single pressure reducing valve 9 can be similarly applied to other embodiments, regardless of the number of liquefied gas sources 2 and the number of gas consumers 3.

[0066] The flow meter 22 is disposed between the second valve 12 and the buffer tank 7. Optionally, the flow meter 22 is disposed upstream of the second valve 12.

[0067] The compressor 20 is wirelessly and remotely controlled by a control unit 25 .

[0068] In the embodiment shown in FIG. 3, the aviation gas distribution device 1 is associated with a liquefied gas source 2 for filling three buffer tanks 7 that supply gas to the gas consumers 3 (for example, the engines). For reasons similar to those of the embodiment of FIG. 2, the first valve 11 may be omitted. The flow meter 22 is arranged at the outlet of the liquefied gas source 2. The presence of three buffer tanks 7 increases the autonomy for the aircraft in case of failure of the liquefied gas source 2 (for example, in an event that may require the liquefied gas source 2 to be emptied). Furthermore, the provision of three buffer tanks 7 provides redundancy in that the aviation gas distribution device 1 can be fully operated even with only two buffer tanks 7. The cryogenic distributor 5 may comprise a valve with one inlet and three outlets (one for each buffer tank 7). In particular, if the valve associated with the compressor 20 is controlled, the supply valve 24 associated with the gas consumers 3 may be omitted.

[0069] The embodiment of Fig. 3 is suitable for an aircraft with two assemblies, each having an aviation gas distribution device 1 and at least one source of cryogenic liquefied gas, each of which may be mounted symmetrically in the aircraft (e.g. inside or under the left and right wings).

[0070] In the embodiment shown in FIG. 4, the aviation gas distribution device 1 is associated with two liquefied gas sources 2 for filling three buffer tanks 7 supplying gas consumers 3 .

[0071] In the embodiment shown in FIG. 5, the aviation gas distribution device 1 is associated with one liquefied gas source 2 for filling two buffer tanks 7 supplying the gas consumers 3. For the same reasons as in the embodiment of FIG. 2, the first valve 11 can be omitted. The operation is then adapted. The duration of the gasification phase can be shortened, in particular by a heating element 8 for each or several buffer tanks 7. Furthermore, while the discharge from one buffer tank 7 takes place via the third valve 13 and then via the fifth valve 15, the other buffer tank 7 is in the gasification phase after being filled with liquid. The timing of the switch between the third valve 13 and the fifth valve 15 is independent of the timing of the closing of the second valve 12.

[0072] In general, the number X of cryogenic tanks, the number Y of buffer tanks 7, and the number Z of gas consumers are independent of each other. The number X of cryogenic tanks is 1 or more, the number Y of buffer tanks 7 is 2 or more, and the number Z of gas consumers is 1 or more.

[0073] The volume of each buffer tank 7 is equal to or greater than 10% and equal to or less than 20% of the volume of each liquefied gas source 2 .

[0074] Since the cryogenic tank (liquefied gas source 2) is subject to evaporation of the liquefied gas, a gas collection circuit may be provided on top of the cryogenic tank (liquefied gas source 2). 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).

[0075] Optionally, additional flow meters may be placed at the inlet of each buffer tank, providing redundancy in liquid flow measurement.

[0076] The first valve 11 may be of the monostable or bistable type. The first valve 11 may be controlled to open for a duration corresponding to the filling of one buffer tank 7 or by pulse width modulation. The second valve 12 may be of the monostable or bistable type. The second valve 12 may be controlled to open for a duration corresponding to the filling of one buffer tank 7 or by pulse width modulation.

Claims

1. An aviation gas distribution device (1) for distributing gas between at least one liquefied gas source (2) and at least one gas consumer (3) in an aircraft, comprising: at least one on-off controlled first valve (11) at the outlet of each of said liquefied gas sources (2); a cryogenic distributor (5) connected to each of said first valves (11) for the supply of liquid; a plurality of on-off controlled second valves (12) connected in parallel to the cryogenic distributor (5); a two-phase buffer tank (7) arranged to be supplied with liquid and with gas via each of said second valves (12); a third valve (13) controllably provided at the outlet of each of said buffer tanks (7) for supplying gas; a pressure reducing valve (9) provided at the outlet of the third valve (13); a manifold (10) provided to supply the gas supplied via the pressure reducing valve (9) to the at least one gas consuming unit (3); 1. An aviation gas distribution device comprising:

2. a fourth valve (14) controllably arranged at the outlet of each of said pressure reducing valves (9) for supplying gas; 2. An aviation gas distribution apparatus as claimed in claim 1.

3. at least one compressor (20) supplied with gas from at least one said buffer tank (7); and at least one fifth valve (15) controllably arranged between the compressor (20) and the buffer tank (7).

3. An aviation gas distribution device according to claim 1 or 2.

4. a control unit for controlling said at least one first valve (11) for sequential filling and sequential draining of said buffer tank (7) by pressure difference. An aviation gas distribution device according to any one of claims 1 to 3.

5. said control unit controls said third valve to allow gas flow, first by pressure difference and then by operation of a compressor (20), for discharge from one of said buffer tanks (7), until the pressure in said buffer tank (7) is lower than the pressure in said cryogenic distributor (5); 5. An aviation gas distribution device according to claim 3 or claim 4.

6. the at least one first valve (11) and the second valve (12) are cryogenic; A flow meter (22) is disposed at the outlet of each of the liquefied gas sources (2); Preferably, a further flow meter is arranged at the inlet of the buffer tank (7). An aviation gas distribution device according to any one of claims 1 to 3.

7. 7. An assembly comprising an aviation gas distribution device according to any one of claims 1 to 6 and at least one source of cryogenic liquefied gas.

8. A method for distributing gas in an aircraft between at least one liquefied gas source (2) and at least one gas consumer (3), comprising: a filling step of filling one of the at least two buffer tanks (7) with liquefied gas via at least one on-off controlled first valve (11) at the outlet of each of the liquefied gas sources (2), a cryogenic distributor (5) connected to each of the first valves (11) so as to supply liquid, and one of a plurality of on-off controlled second valves (12) connected in parallel to the cryogenic distributor (5), wherein the second valve (12) connected to one of the buffer tanks (7) is open, the other second valve (12) is closed, and a third valve (13) controllably provided at the outlet of one of the buffer tanks (7) is closed; a discharge step from the buffer tank (7), in which the second valve (12) is closed, the third valve (13) is open, and the gas supplied to the at least one gas consumer (3) flows through a pressure reducing valve (9) provided at the outlet of the third valve (13); 1. A method for distributing gas for an aviation vehicle comprising:

9. The at least two buffer tanks (7) include a first buffer tank (7), a second buffer tank (7) and a third buffer tank (7); During normal operation, the first buffer tank (7) is in the process of being filled with liquid by pressure balancing through at least one of the first valve (11) in an open state and the second valve (12) corresponding to the first buffer tank (7) while the third valve (13) corresponding to the first buffer tank (7) is closed; the second buffer tank (7) is in the process of supplying pressurized gas with the second valve (12) corresponding to the second buffer tank (7) closed and the third valve (13) corresponding to the second buffer tank (7) open; the third buffer tank (7) is in the process of undergoing gasification with the second valve (12) corresponding to the third buffer tank (7) closed and the third valve (13) corresponding to the third buffer tank (7) closed; 9. The method of claim 8 for dispensing gas for an aviation application.

10. The discharge step includes: a first sub-step of discharging gas from the buffer tank (7) by means of the pressure reducing valve (9) to reduce the gas pressure to the pressure required for the gas consumer (3); said first sub-step is followed by a second sub-step of evacuating gas from said buffer tank (7) with the aid of a pump, so as to reduce the pressure of the gas to the pressure required for said gas consumer (3) and to reduce the pressure in said buffer tank (7) at the end of said evacuating step to a value lower than the pressure present in the cryogenic distributor (5); 10. The method of claim 8 or claim 9, comprising:

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