AIRPORT FACILITY COMPRISING A PLURALITY OF DIHYDROGEN STORAGE TANKS
The airport facility with multiple tanks at varying saturation pressures addresses inefficiencies in supplying different aircraft by using transfer and filling systems to match saturation pressures, enhancing efficiency and reducing hydrogen loss.
Patent Information
- Application Number
- FR2023010199
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-09-26
- Publication Date
- 2025-10-17
- Estimated Expiration
- 2043-09-26
AI Technical Summary
Existing airport facilities face inefficiencies in supplying different types of aircraft with dihydrogen due to mismatched saturation pressures in storage tanks, leading to energy consumption or hydrogen loss during filling and venting processes.
An airport installation with multiple storage tanks at different saturation pressures, each designed to supply specific aircraft types, along with transfer and filling systems to manage dihydrogen efficiently, ensuring compatible saturation pressures and minimizing losses.
Enables efficient filling of different aircraft types while reducing energy consumption and hydrogen loss by matching saturation pressures across tanks, optimizing the airport's hydrogen supply infrastructure.
Smart Images
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Abstract
Description
Title of the invention: AIRPORT FACILITY COMPRISING A PLURALITY OF DIHYDROGEN STORAGE TANKS Technical field
[0001] The present invention relates to an airport installation comprising a plurality of storage tanks at different saturation pressures in order to be able to supply different types of aircraft, as well as a method for managing such an airport installation. STATE OF THE PRIOR ART
[0002] In the context of reducing kerosene consumption in aircraft engines, it is known to use dihydrogen as fuel. To do this, the aircraft has a dihydrogen tank and the airport has a dihydrogen storage tank and a tanker truck travels between the two to fill the storage tank and the tank to fill the latter.
[0003] The hydrogen is stored at low temperature in the airport storage tank and the aircraft tank. The storage temperature of the hydrogen depends, among other things, on the saturation pressure inside the tank, and the higher the temperature, the higher the saturation pressure.
[0004] Each aircraft tank is designed to operate with a particular saturation pressure which ensures a particular balance between liquid dihydrogen and gaseous dihydrogen.
[0005] If the saturation pressure of the storage tank is lower than the saturation pressure of the aircraft tank, it is necessary to heat the dihydrogen to increase its saturation pressure, which results in additional energy consumption.
[0006] If the saturation pressure of the storage tank is higher than the saturation pressure of the aircraft tank, it is necessary to vent the aircraft tank by allowing dihydrogen to escape, which results in a loss of dihydrogen.
[0007] To limit losses, it is therefore necessary to find a port facility that can meet the requirements related to the storage of dihydrogen in aircraft tanks. Statement of the invention
[0008] An object of the present invention is to provide an airport installation which comprises a plurality of hydrogen storage tanks at different saturation pressures in order to be able to supply different types of aircraft.
[0009] For this purpose, an airport installation is proposed comprising:
[0010] - a plurality of aircraft types where each aircraft of a type comprises a tank intended to contain dihydrogen at a saturation pressure included in a first interval among a plurality of first intervals, where each first interval is different from the other first intervals,
[0011] - for each type of aircraft, a storage tank at a saturation pressure included in a second interval different from the other second intervals, and
[0012] - for each storage tank, filling means intended to fill from said storage tank, the aircraft tank corresponding to said storage tank.
[0013] With such an installation, it is possible to fill the tanks of different types of aircraft while limiting losses.
[0014] Advantageously, there are three types of aircraft. For a first type of aircraft, the first saturation pressure interval of the tank is [1.2 bars, 2 bars] and the second interval P' 1 of a first storage tank is [1.05 bars, 1.2 bars], for a second type of aircraft, the first interval is [2 bars, 4 bars] and the second interval of a second storage tank is [2 bars, 3 bars] and for a third type of aircraft, the first interval is [4 bars, 6 bars] and the second interval of a third storage tank is [4 bars, 5 bars].
[0015] Advantageously, the airport installation comprises a first transfer system intended to ensure the transfer of dihydrogen from the tank of the first type of aircraft to the tank of the second type of aircraft, and a second transfer system intended to ensure the transfer of dihydrogen from the tank of the second type of aircraft to the tank of the third type of aircraft.
[0016] Advantageously, the airport installation comprises a first filling system intended to ensure the transfer of dihydrogen from the tank of the first type of aircraft to the second storage tank, and a second filling system intended to ensure the transfer of dihydrogen from the tank of the second type of aircraft to the third storage tank.
[0017] According to a particular embodiment, the airport installation comprises a first discharge system intended to ensure the transfer of dihydrogen from the first storage tank to the second storage tank, and a second discharge system intended to ensure the transfer of dihydrogen from the second storage tank to the third storage tank.
[0018] Advantageously, the airport installation comprises a fourth storage tank at a saturation pressure greater than 5 bars, and a third discharge system intended to ensure the transfer of dihydrogen from the third tank of storage to the fourth storage tank.
[0019] Advantageously, the airport installation comprises a third filling system intended to ensure the transfer of dihydrogen from the tank of the third type of aircraft to the fourth storage tank.
[0020] According to a particular embodiment, the storage tanks are fluidically independent of each other.
[0021] Advantageously, the airport installation comprises a fourth storage tank fluidically independent of the other storage tanks.
[0022] The invention also proposes a method for managing an airport facility according to the preceding variant, in which, from a situation where the first storage tank is at a first degree of filling such that it is at a saturation pressure in the second interval of [1.05 bars, 1.2 bars], where the second storage tank is at a second degree of filling such that it is at a saturation pressure in the second interval of [2 bars, 3 bars], where the third storage tank is at a third degree of filling such that it is at a saturation pressure in the second interval of [4 bars, 5 bars], where the fourth storage tank is at a fourth degree of filling such that it is at a saturation pressure greater than 5 bars, each storage tank passes successively and in parallel from the first degree of filling with a saturation pressure in the second interval of [1.05 bars, 1,2 bars] to the second degree of filling with a saturation pressure in the second interval of [2 bars, 3 bars] to the third degree of filling with a saturation pressure in the second interval of [4 bars, 5 bars] to the fourth degree of filling with a saturation pressure greater than 5 bars and to the first degree of filling with a saturation pressure in the second interval of [1.05 bars, 2 bars] and so on. Brief description of the drawings
[0023] The above-mentioned features of the invention, as well as others, will appear more clearly on reading the following description of an exemplary embodiment, said description being made in relation to the attached drawings, among which:
[0024] [Fig.l] is a schematic representation of an airport installation according to a first embodiment of the invention, and
[0025] [Fig.2] is a schematic representation of an airport installation according to a second embodiment of the invention.
[0026] DETAILED DESCRIPTION OF EMBODIMENTS
[0027] [Fig.l] shows an airport installation 100 according to a first embodiment of the invention and [Fig.2] shows an airport installation 200 according to a second embodiment of the invention.
[0028] The airport installation 100, 200 makes it possible to supply dihydrogen to different types of aircraft 102a-c, which are here of three types. Each aircraft 102a-c comprises a tank 104a-c which contains dihydrogen at a particular saturation pressure depending on the type of aircraft 102a-c.
[0029] Thus, each tank 104a-c of an aircraft 102a-c of a particular type contains dihydrogen at a saturation pressure comprised in a first interval PI, P2, P3 among a plurality of first intervals PI, P2, P3.
[0030] According to a particular embodiment of the invention, the saturation pressure for an aircraft of the first type 102a is included in the first interval PI equal to [1.2 bars, 2 bars], the saturation pressure for an aircraft of the second type 102b is included in the first interval P2 equal to [2 bars, 4 bars] and the saturation pressure for an aircraft of the third type 102c is included in the first interval P2 equal to [4 bars, 6 bars].
[0031] Each first interval PI, P2, P3 is different from the other first intervals PI, P2, P3, that is to say that the first intervals PI, P2, P3 do not overlap, although they may have common limits.
[0032] For each type of aircraft 102a-c and therefore for each first interval P1, P2, P3, the airport installation 100, 200 comprises a storage tank 106a-c which is at a saturation pressure included in a second interval P' 1, P'2, P'3 where, for each type, the second interval P' 1, P'2, P'3 is different from the other second intervals P'1, P'2, P'3, that is to say that the second intervals P'1, P'2, P'3 do not overlap, although they may have common limits.
[0033] In the embodiment of the invention presented here, for the first type of aircraft 102a, a first storage tank 106a is at a saturation pressure which is in the second interval P' 1 equal to [1.05 bars, 1.2 bars], for the second type of aircraft 102b, a second storage tank 106b is at a saturation pressure which is in the second interval P'2 equal to [2 bars, 3 bars] and for the third type of aircraft 102c, a third storage tank 106c is at a saturation pressure which is in the second interval P'3 equal to [4 bars, 5 bars].
[0034] Thus, in the embodiment of the invention presented here, two of the second intervals, namely P'2 and P'3 are included in the first interval P2 and P3 associated with the aircraft type 102b-c.
[0035] Even if the interval P'1 [1.05 bar, 1.2 bar] is not included in the interval PI [1.2 bar, 2 bar], during its transfer from the storage tank 106a to the tank 104a of the aircraft 102a, the dihydrogen heats up, which causes an increase in the saturation pressure and the dihydrogen arrives in the tank 104a of the aircraft 102a with a saturation pressure of at least 1.2 bar. Thus, the saturation pressure of the dihydrogen is included in the first interval PI.
[0036] Thus, in general, the dihydrogen is stored in a storage tank 106a-c at a saturation pressure included in a second interval P' 1, P'2, P'3 which is such that the saturation pressure of the dihydrogen which arrives in the tank 104a-c of the aircraft 102a-c is included in the first interval P1, P2, P3 corresponding to the aircraft 102a-c.
[0037] To supply each type of aircraft 102a-c from the storage tank 106a-c whose saturation pressure is compatible with the saturation pressure of the tank 104a-c of the type considered, the airport installation 100, 200 also comprises, for each storage tank 106a-c, filling means 108a-c which ensure the filling, from the storage tank 106a-c considered, of the tank 104a-c of the aircraft 102a-c of the compatible type.
[0038] There are thus filling means 108a for filling the tank 104a of the aircraft 102a of the first type corresponding to the first interval P1 from the first tank 106a corresponding to the second interval P'1, filling means 108b for filling the tank 104b of the aircraft 102b of the second type corresponding to the first interval P2 from the second tank 106b corresponding to the second interval P'2, and filling means 108c for filling the tank 104c of the aircraft 102c of the third type corresponding to the first interval P3 from the third tank 106c corresponding to the second interval P'3.
[0039] The filling means 108a-c are for example tank trucks which ensure the transport of dihydrogen from a storage tank 106a-c to a tank 104a-c of aircraft 102a-c. The tank of the tank truck can be adapted to operate with all the second intervals P' 1, P'2, P'3 provided or only for one of them and there is then a tank truck for each second interval P' 1, P'2, P'3.
[0040] The filling means 108a-c can also be pipes equipped with pumps.
[0041] In the embodiments of the invention presented here, the dihydrogen is delivered into the first storage tank 106a from a liquefaction system 50 which ensures the liquefaction of the dihydrogen at the saturation pressure corresponding to the second interval P'1 with the lowest pressures, i.e. here the second interval [1.05 bar, 1.2 bar]. The transport of the dihydrogen from the liquefaction system 50 to the first storage tank 106a is carried out by any suitable first transport means 52, such as a tanker truck or a pipeline with a pump.
[0042] In a first variant of the first embodiment, as the temperature of the dihydrogen present in the storage tank 106c at the saturation pressure corresponding to the highest pressures increases, then the pressure of saturation of said storage tank 106c also increases and to prevent it from leaving the second interval (here P'3), the dihydrogen is partly evacuated towards a fuel cell 54 or towards the liquefaction system 50 by second 56, respectively third 58 suitable means of transport such as a tanker truck or a pipeline with a pump.
[0043] The fuel cell 54 can electrically power the liquefaction system 50 or any other electrical system 60.
[0044] In a second variant of the first embodiment of the invention and in the second embodiment, the airport installation 100, 200 comprises a fourth storage tank 106d which is at a saturation pressure greater than 5 bars.
[0045] In these cases, to limit heating of the dihydrogen in the fourth storage tank 106d, the dihydrogen is partly evacuated to the fuel cell 54 or to the liquefaction system 50 by fourth 62, respectively fifth 64 suitable means of transport such as a tanker truck or a pipeline with a pump.
[0046] According to a particular embodiment, the airport installation 100, 200 comprises a first transfer system 112a which ensures the transfer of dihydrogen from the tank 104a of an aircraft 102a of the first type of aircraft 102a to the tank 104b of an aircraft 102b of the second type of aircraft 102b, and a second transfer system 112b which ensures the transfer of dihydrogen from the tank 104b of the aircraft 102b of the second type of aircraft 102b to the tank 104c of the aircraft 102c of the third type of aircraft 102c.
[0047] With such an arrangement, when the temperature of the dihydrogen present in the tank 104a-b of an aircraft 102a-b increases, it is transferred to the tank 104b-c of the aircraft 102b-c whose first interval has pressures higher than that of the first interval of the original aircraft 102a-b.
[0048] Each transfer system 112a-b is for example a tanker truck or a pipeline with a pump.
[0049] According to a particular embodiment of the invention, the airport installation 100, 200 comprises a first filling system 114a which ensures the transfer of dihydrogen from the tank 104a of the aircraft 102a of the first type of aircraft 102a to the second storage tank 106b, and a second filling system 114b which ensures the transfer of dihydrogen from the tank 104b of the aircraft 102b of the second type of aircraft 102b to the third storage tank 106c.
[0050] When there is the fourth storage tank 106d, the airport installation 100, 200 comprises a third filling system 114c intended to ensure the transfer of dihydrogen from the tank 104c of the aircraft 102c of the third type. aircraft 102c to the fourth storage tank 106d.
[0051] Thus, when the temperature of the dihydrogen present in the tank 104a-c of an aircraft 102a-c increases, it is transferred to the storage tank 106b-d whose second interval or whose saturation pressure has pressures higher than those of the first interval of the original aircraft 102a-c.
[0052] Each filling system 114a-c is for example a tanker truck or a pipeline with a pump.
[0053] In the first embodiment of the invention, the airport installation 100 comprises a first discharge system 110a which ensures the transfer of dihydrogen from the first storage tank 106a to the second storage tank 106b, and a second discharge system 110b which ensures the transfer of dihydrogen from the second storage tank 106b to the third storage tank 106c, and when there is the fourth storage tank 106d, a third discharge system 110c which ensures the transfer of dihydrogen from the third storage tank 106c to the fourth storage tank 106d.
[0054] Thus, when the temperature of the dihydrogen present in a storage tank 106a increases, it is transferred to the storage tank 106b-d whose second interval or whose saturation pressure has pressures higher than those of the second interval of the original storage tank.
[0055] Each discharge system 110a-c is for example a tanker truck or a pipeline with a pump.
[0056] In the second embodiment of the invention, the storage tanks 106a-d are fluidically independent of each other, i.e. there is no transfer of dihydrogen between them.
[0057] In the second embodiment of the invention, to compensate for the absence of the discharge systems, each storage tank 106a-d regularly changes saturation pressure due to the fact that it empties or that the dihydrogen heats up. There is then a cyclical change of the second intervals and of the saturation pressure greater than 5 bars.
[0058] Thus, in the example of [Fig. 2], the saturation pressure of the first storage tank 106a is between [1.05 bars, 1.2 bars], the saturation pressure of the second storage tank 106b is between [2 bars, 3 bars], the saturation pressure of the third storage tank 106c is between [4 bars, 5 bars] and the saturation pressure of the fourth storage tank 106d is greater than 5 bars. Each storage tank 106a-d supplies the aircraft type 102a-c corresponding to its saturation pressure, which corresponds for example for the first storage tank 106a to a complete filling, for the second storage tank 106b to a 2 / 3 filling, for the third storage tank 106c to a filling to 1 / 3 and for the fourth storage tank 106d to an almost empty filling. These filling values are given for information purposes only. They may vary in particular in the event of prolonged non-use of the airport facility. Indeed, in such a case, the saturation pressure in a storage tank 106a-d increases over time, even in the absence of hydrogen sampling from the storage tank 106a-d.
[0059] The first storage tank 106a is supplied with dihydrogen by the liquefaction system 50 and the fourth storage tank 106d supplies the liquefaction system 50 or the fuel cell 54 by ventilation.
[0060] When the fourth storage tank 106d is practically empty, it is filled from the liquefaction system 50. It is then at a complete filling with a saturation pressure between [1.05 bars, 1.2 bars].
[0061] At the same time, the other storage tanks 106a-c are emptied or heated.
[0062] The first storage tank 106a is then 2 / 3 full with a saturation pressure between [2 bars, 3 bars], and it can be supplied by the tanks 104a of the aircraft 102a of the first type by a suitable filling system.
[0063] The second storage tank 106b is then 1 / 3 full with a saturation pressure between [4 bars, 5 bars], and it can be supplied by the tanks 104b of the aircraft 102b of the second type by a suitable filling system.
[0064] The third storage tank 106c is then practically empty with a saturation pressure greater than 5 bars, and it can be supplied by the tanks 104c of the aircraft 102c of the third type by a suitable filling system. If necessary, the dihydrogen ventilated from the third storage tank 106c supplies the liquefaction system 50 or the fuel cell 54.
[0065] When the third storage tank 106c is practically empty, it is filled from the liquefaction system 50. It is then at a complete filling with a saturation pressure between [1.05 bars, 1.2 bars].
[0066] At the same time, the other storage tanks are emptying or heating up.
[0067] The first storage tank 106a is then 1 / 3 full with a pressure of its turation between [4 bars, 5 bars], and it can be supplied by the tanks 104b of the aircraft 102b of the second type by a suitable filling system.
[0068] The second storage tank 106b is then practically empty with a saturation pressure greater than 5 bars and it can be supplied by the tanks 104c of the aircraft 102c of the third type by a suitable filling system. If necessary, the dihydrogen ventilated from the second storage tank 106b supplies the liquefaction system 50 or the fuel cell 54.
[0069] The fourth storage tank 106d is 2 / 3 full with a pressure of its turation between [2 bars, 3 bars], and it can be supplied by the tanks 104a of the aircraft 102a of the first type by a suitable filling system.
[0070] When the second storage tank 106b is practically empty, it is filled from the liquefaction system 50. It is then at a complete filling with a saturation pressure between [1.05 bars, 1.2 bars].
[0071] At the same time, the other storage tanks are emptied or heated.
[0072] The first storage tank 106a is then practically empty with a saturation pressure greater than 5 bars, and it can be supplied by the tanks 104c of the aircraft 102c of the third type by a suitable filling system. If necessary, the dihydrogen vented from the first storage tank 106a supplies the liquefaction system 50 or the fuel cell 54.
[0073] The third storage tank 106c is then 2 / 3 full with a higher saturation pressure between [2 bars, 3 bars] and it can be supplied by the tanks 104a of the aircraft 102a of the first type by a suitable filling system.
[0074] The fourth storage tank 106d is 1 / 3 full with a saturation pressure between [4 bars, 5 bars], and it can be supplied by the tanks 104b of the aircraft 102b of the second type by a suitable filling system.
[0075] The first reservoir 106a is then refilled and the cycle begins again.
[0076] Each storage tank 106a-d therefore performs a permutation and takes success sively the position of first storage tank with a saturation pressure between [1.05 bar, 1.2 bar], second storage tank with a saturation pressure between [2 bar, 3 bar], third storage tank with a saturation pressure between [4 bar, 5 bar] and fourth storage tank with a saturation pressure greater than 5 bar and so on. The filling means are adapted as and when to allow the supply of the type of aircraft corresponding to the saturation pressure. In the same way, the transfer systems are modified accordingly.
[0077] Thus, from a situation where the first storage tank 106a is at a first degree of filling (full) such that it is at a saturation pressure in the second interval P'1 of [1.05 bars, 1.2 bars], where the second storage tank 106b is at a second degree of filling (2 / 3 full) such that it is at a saturation pressure in the second interval P'2 of [2 bars, 3 bars], where the third storage tank 106c is at a third degree of filling (1 / 3 full) such that it is at a saturation pressure in the second interval P'3 of [4 bars, 5 bars], and where the fourth storage tank 106d is at a fourth degree of filling (practically empty) such that it is at a saturation pressure greater than 5 bars, a method for managing the airport facility 200 consists in that each storage tank 106a-d passes successively and in parallel with the first degree of filling with a saturation pressure in the second interval P'1 of [1.05 bar, 1.2 bar] to the second degree of filling with a saturation pressure in the second interval P'2 of [2 bar, 3 bar] to the third degree of filling with a saturation pressure in the second interval P'3 of [4 bar, 5 bar] to the fourth degree of filling with a saturation pressure greater than 5 bar and to the first degree of filling with a saturation pressure in the second interval P' 1 of [1.05 bar, 2 bar] and so on.
Claims
Claims
1. Airport installation (100, 200) comprising: - a plurality of aircraft types (102a-c) where each aircraft (102a-c) of a type comprises a tank (104a-c) intended to contain di-hydrogen at a saturation pressure included in a first interval (PI, P2, P3) among a plurality of first intervals (PI, P2, P3), where each first interval (PI, P2, P3) is different from the other first intervals (PI, P2, P3), - for each aircraft type (102a-c), a storage tank (106a-c) at a saturation pressure included in a second interval (P' 1, P'2, P'3) different from the other second intervals (P' 1, P'2, P'3), and - for each storage tank (106a-c), filling means (108a-c) intended to fill from said tank storage tank (106a-c), the tank (104a-c) of the aircraft (102a-c) corresponding to said storage tank (106a-c).
2. Airport installation (100, 200) according to claim 1, characterized in that there are three types of aircraft (102a-c), in that for a first type of aircraft (102a), the first interval (P1) is [1.2 bar, 2 bar] and the second interval (P' 1) of a first storage tank (106a) is [1.05 bar, 1.2 bar], in that for a second type of aircraft (102b), the first interval (P2) is [2 bar, 4 bar] and the second interval (P'2) of a second storage tank (106b) is [2 bar, 3 bar] and in that for a third type of aircraft (102c), the first interval (P3) is [4 bar, 6 bar] and the second interval (P'3) of a third storage tank (106c) is [4 bars, 5 bars].
3. Airport installation (100, 200) according to claim 2, characterized in that it comprises a first transfer system (112a) intended to ensure the transfer of dihydrogen from the tank (104a) of the first type of aircraft (102a) to the tank (104b) of the second type of aircraft (102b), and a second transfer system (112b) intended to ensure the transfer of dihydrogen from the tank (104b) of the second type of aircraft (102b) to the tank (104c) of the third type of aircraft (102c).
4. Airport installation (100, 200) according to one of claims 2 or 3, characterized in that it comprises a first filling system (114a) intended to ensure the transfer of dihydrogen from the tank (104a) of the first type of aircraft (102a) to the second tank of storage (106b), and a second filling system (114b) intended to ensure the transfer of dihydrogen from the tank (104b) of the second type of aircraft (102b) to the third storage tank (106c).
5. Airport installation (100) according to one of claims 2 to 4, characterized in that it comprises a first discharge system (110a) intended to ensure the transfer of dihydrogen from the first storage tank (106a) to the second storage tank (106b), and a second discharge system (110b) intended to ensure the transfer of dihydrogen from the second storage tank (106b) to the third storage tank (106c).
6. Airport installation (100) according to claim 5, characterized in that it comprises a fourth storage tank (106d) at a saturation pressure greater than 5 bars, and a third discharge system (110c) intended to ensure the transfer of dihydrogen from the third storage tank (106c) to the fourth storage tank (106d).
7. Airport installation (100) according to claim 6, characterized in that it comprises a third filling system (114c) intended to ensure the transfer of dihydrogen from the tank (104c) of the third type of aircraft (102c) to the fourth storage tank (106d).
8. Airport installation (200) according to one of claims 2 to 4, characterized in that the storage tanks (106a-c) are fluidically independent of each other.
9. Airport installation (200) according to claim 8, characterized in that it comprises a fourth storage tank (106d) fluidically independent of the other storage tanks (106a-c).
10. A method for managing an airport facility (200) according to claim 9, wherein from a situation where the first storage tank (106a) is at a first degree of filling such that it is at a saturation pressure in the second interval (P' 1) of [1.05 bar, 1.2 bar], where the second storage tank (106b) is at a second degree of filling such that it is at a saturation pressure in the second interval (P'2) of [2 bar, 3 bar], where the third storage tank (106c) is at a third degree of filling such that it is at a saturation pressure in the second interval (P'3) of [4 bar, 5 bar], where the fourth storage tank (106d) is at a fourth degree of filling such that it is at a saturation pressure greater than 5 bar, each storage tank (106a-d) passes successfully- sively and in parallel from the first degree of filling with a saturation pressure in the second interval (P' 1) of [1.05 bars, 1.2 bars] to the second degree of filling with a saturation pressure in the second interval (P'2) of [2 bars, 3 bars] to the third degree of filling with a saturation pressure in the second interval (P'3) of [4 bars, 5 bars] to the fourth degree of filling with a saturation pressure greater than 5 bars and to the first degree of filling with a saturation pressure in the second interval (P' 1) of [1.05 bars, 2 bars] and so on.