Method for testing the tightness of a high-pressure tank
The method of liquefying and vaporizing gas in a buffer tank for high-pressure tank tightness testing addresses energy inefficiencies and safety concerns, providing a cost-effective and safer alternative to traditional methods.
Patent Information
- Application Number
- FR2023012970
- Authority / Receiving Office
- FR · FR
- Patent Type
- Patents
- Current Assignee / Owner
- Filing Date
- 2023-11-23
- Publication Date
- 2025-10-24
- Estimated Expiration
- 2043-11-23
AI Technical Summary
Existing methods for checking the tightness of high-pressure tanks are energy-intensive, expensive, and complex, requiring multiple gas compressors, heat exchangers, and valves, and pose safety risks due to the use of flammable tracer gases like hydrogen.
A method involving liquefaction and vaporization of gas followed by mixing in a buffer tank to create a gas mixture, which is then used to test the tank's tightness, eliminating the need for separate compressors and heat exchangers, and reducing safety risks by managing tracer gas in a centralized system.
This approach reduces energy consumption, lowers costs, simplifies the process, and enhances safety by minimizing the need for complex equipment and handling hazardous gases, allowing for efficient and secure tightness testing.
Smart Images
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Abstract
Description
Title of the invention: Method for checking the tightness of a high-pressure tank
[0001] The invention relates to a method for checking the tightness of a high-pressure tank at the end of a production line, in particular for motor vehicles, as well as an installation for checking the tightness of said high-pressure tank at the end of a production line.
[0002] It is mandatory to check the leaktightness of all high-pressure tanks before commissioning. These leaktightness checks are carried out during a gas leak test, at the end of the production line. During this test, the tank is placed in an administration chamber to be filled with a gas up to a test pressure. The test pressure, i.e. the pressure in the tank to carry out the check, is generally greater than or equal to the maximum operating pressure, also called nominal pressure, of the tank. The administration chamber is equipped with sensors to detect any possible gas leak. The leak test is carried out at a filling temperature which must be less than 85°C and greater than -40°C.The gas used is generally a mixture of 5% by weight of H2 (dihydrogen, commonly called hydrogen) and 95% by weight of N2 (dinitrogen, commonly called nitrogen), in which hydrogen is used as a tracer gas. Hydrogen can be replaced by helium. The tracer gas is used to detect a leak using a spectrometer.
[0003] A gas leak test is already known in the prior art, in which a nitrogen gas source and a hydrogen gas source are used. Such a test requires the use of series of gas compressors, series of heat exchangers to control the inlet temperature in the compressors, and valves to control the compressor inlet pressure. Such a test therefore consumes a lot of energy and is very expensive. Its management is also complex because it involves many steps.
[0004] The invention aims in particular to propose a method for checking the tightness of a high-pressure tank which consumes less energy.
[0005] To this end, the invention relates to a method for checking the tightness of a high-pressure tank. The method comprises the following steps: (a) pumping and compressing a liquefied gas by means of a pump from a source of liquefied gas, so as to obtain a compressed liquefied gas at a pressure ranging from 500 to 1000 bar, then b) vaporizing the compressed liquefied gas obtained in step a) so as to obtain a vaporized liquefied gas, (c) compressing a tracer gas so as to obtain a compressed tracer gas at a pressure ranging from 500 to 1000 bar, d) mixing the vaporized liquefied gas obtained in step b) with the compressed tracer gas obtained in step c) in a buffer tank so as to obtain a gas mixture, e) filling the high pressure tank to be controlled with the gas mixture obtained in step d), then f) look for a tracer gas leak on the high pressure tank to be checked.
[0006] By pumping and vaporizing gas in liquefied form rather than in gaseous form, the use of series of gas compressors, series of heat exchangers and series of valves to control pressure is avoided. Thus, a less energy-consuming and less expensive process is provided.
[0007] It will be noted that a buffer tank is advantageously used to mix the vaporized liquefied gas with the compressed tracer gas, whereas it could have been imagined to administer the tracer gas directly into the tank to be controlled, and to mix the vaporized liquefied gas with the tracer gas in the tank to be controlled. However, although compression of the tracer gas would not have been necessary, and it would not have been necessary to use a buffer tank, the proposed method is particularly safe.
[0008] The term "buffer tank" preferably means a tank whose volume is such that it can fill several high-pressure tanks to be controlled. Thus, with the buffer tank, it is possible to make only one gas mixture to control several high-pressure tanks. Without the buffer tank, it would be necessary to make as many gas mixtures as there are tanks, which is more restrictive.
[0009] Furthermore, by multiplying the number of separate mixtures to be made, the difficulty in obtaining each time a mixture which has the quality required for the leak test is multiplied.
[0010] The quality of the gas mixture is determined by the proportion of each gas present in the gas mixture. A gas mixture that has the required quality is a gas mixture in which the proportion of each gas present in the gas mixture conforms to a target proportion. Thus, thanks to the buffer tank, it is not necessary to equip each tank to be controlled with means for controlling the quality of the gas mixture. This results in a simpler installation and a process that takes less time to implement.
[0011] Furthermore, in the case where the tracer gas is hydrogen, this gas being flammable, it is necessary to manage the risk of fire or explosion, which complicates the leak test. By mixing the hydrogen with the liquefied gas in the buffer tank, it is possible to avoid having to manage these risks at each high-pressure tank to be tested.
[0012] This provides a test requiring less complex and more secure installation.
[0013] According to other optional characteristics of the leak testing method, taken alone or in combination:
[0014] - The pump includes a cold head. The cold head of the pump is the part of the pump which serves as an inlet-outlet for liquefied gas.
[0015] - The pump is a cryogenic pump, also called a cryopump.
[0016] Thus, it is possible to compress a liquefied gas having a negative temperature.
[0017] - The cryogenic pump is a piston cryogenic pump.
[0018] - The high pressure tank is a tank intended to be filled with a gas at a maximum filling pressure of 875 bar. For example, it is a type IV high-pressure tank, composed of an internal envelope called a "liner" surrounded by a reinforcing structure, whose maximum operating pressure, also called nominal pressure, is 700 bar.
[0019] - The high pressure tank is intended to contain hydrogen at high pressure.
[0020] - Mixing the vaporized liquefied gas with the compressed tracer gas in the tank buffer is carried out at a pressure ranging from 500 to 1000 bar.
[0021] - The test pressure is between 350 and 700 bar.
[0022] - Liquefied gas is liquid nitrogen. This gas has the advantage of being low expensive, and its use does not involve the same risks as hydrogen, such as the risk of generating an explosive atmosphere.
[0023] - Liquefied nitrogen is pumped from a source of liquefied nitrogen at a pressure of about 10 bar, for example a liquefied nitrogen storage tank pressurized to a pressure below 15 bar, for example 10 bar.
[0024] - Liquefied nitrogen is pumped and compressed using a cryogenic pump capable of working at temperatures as low as -253°C.
[0025] - The tracer gas can be hydrogen or helium, helium being more expensive than hydrogen but less dangerous. Advantageously, the mixture of liquefied gas vaporized with the tracer gas is a mixture containing a proportion ranging from 95% to 96% by weight of nitrogen and from 4 to 5% by weight of hydrogen. Alternatively, the gas mixture is a mixture containing a proportion ranging from 95 to 98% by weight of nitrogen and from 2 to 5% by weight of helium.
[0026] - The liquefied gas is pumped and compressed so as to obtain a liquefied gas compressed to a pressure ranging from 900 to 1000 bar, preferably about 1000 bar, and the tracer gas is compressed so as to obtain a tracer gas compressed to a pressure ranging from 900 to 1000 bar, preferably about 1000 bar. Thus, it is not necessary to compress the gas mixture before filling the tank to be controlled, it is directly at the desired pressure.
[0027] - The liquefied gas is pumped and compressed so as to obtain a liquefied gas compressed to a pressure of approximately 500 bar, the tracer gas is compressed so as to obtain a tracer gas compressed to a pressure of approximately 500 bar, the method comprises before step e) of filling the high pressure tank to be controlled with the gas mixture obtained in step d): - a step of compressing the gas mixture obtained in step d) so as to bring it to a pressure of approximately 1000 bar.
[0028] - The method comprises, before step e), filling the tank to be checked with the gas mixture obtained in step d), a step of cooling said gas mixture, preferably via a heat exchanger itself cooled by liquefied gas circulating from the liquefied gas source. This controls the temperature of the gas mixture required for filling the high-pressure tank, which must remain between -40°C and 85°C. This makes it possible to use the liquefied gas source to cool the gas mixture.
[0029] - The process comprises after step b) of vaporization of the liquefied gas and before step d) of mixing gas in the buffer tank, a step of cooling the vaporized liquefied gas, preferably by injecting liquefied gas from the liquefied gas source into the vaporized liquefied gas. This cools the vaporized liquefied gas.
[0030] - Liquefied gas flows from the liquefied gas source to a cold head of the pump. This makes advantageous use of the liquefied gas source for cooling the pump. The circulation of liquefied gas to the cold head of the pump can be implemented by a thermosyphon system.
[0031] - The method comprises before step d) of mixing gas in the buffer tank, a step of dosing each gas obtained in steps b) and c) so as to control the proportion of each gas in the gas mixture. Preferably, this control is carried out continuously. To obtain a gas mixture of the required quality, the proportion of each gas is controlled during the injection of each gas into the buffer tank. Preferably, the proportion of each gas is controlled by a mass flow meter which measures the mass flow rate of each gas during its injection into the buffer tank. A metering device for each gas is also provided. The metering device is controlled by the mass flow meters according to the mass flow rate measurements recorded. The proportion of each gas present in the gas mixture obtained in step d) is thus controlled, preferably continuously.
[0032] The invention also relates to an installation for implementing a method for checking the tightness of a high-pressure tank, comprising: - an administration chamber, - a pump configured to pump and compress a liquefied gas to a pressure ranging from 500 to 1000 bars, - a vaporizer, - a compressor configured to compress a tracer gas to a pressure ranging from 500 to 1000 bars, - a buffer tank. We understand that the installation includes at least one pump, at least one vaporizer, at least one compressor. This means that maintenance operations can be carried out without requiring the production line to be stopped.
[0033] According to other optional characteristics of the installation taken alone or in combination:
[0034] - The installation comprises two pumps configured to pump and compress the liquefied gas at a pressure ranging from 500 to 1000 bars, and / or comprises two compressors configured to compress the tracer gas to a pressure ranging from 500 to 1000 bars, and / or comprises two vaporizers. This means that maintenance operations can be carried out without requiring the production line to be stopped.
[0035] - A cold head of the pump comprises a device for circulating gas liquefied from the liquefied gas source.
[0036] - The installation further comprises a gas analyzer arranged downstream of the tank buffer and upstream of the high pressure tank to be checked. In this way, the proportion of each gas present in the gas mixture leaving the buffer tank is continuously monitored.
[0037] - The installation further comprises a pipe for injecting liquefied gas from from the liquefied gas source into the vaporized liquefied gas, which is preferably a vaporizer bypass line. This cools the vaporized liquefied gas. A cooled liquefied gas is then injected into the buffer tank, thus lowering the temperature of the gas mixture to be injected into the tank to be controlled. Brief description of the figures
[0038] The invention will be better understood on reading the following description, given solely by way of example and with reference to the appended drawings in which:
[0039] [Fig-1] is a schematic view of an installation according to the invention for the implementation implementation of a leak testing process.
[0040] [Fig.2] schematically shows the circulation of fluids in the process for controlling the sealing according to a first embodiment of the invention.
[0041] [Fig.3] schematically shows the circulation of fluids in the method for controlling the tightness according to a second embodiment of the invention. Detailed description
[0042] In the figures, elements similar to those of the other figures are designated by identical references.
[0043] [Fig. 1] shows a schematic view of an installation for implementing a leak testing method, designated by the general reference 10. In the installation 10 shown, the leak testing of a high-pressure tank 12 can be carried out. The installation 10 comprises an administration chamber 14 in which the high-pressure tank 12 is placed to be filled with a gas up to a test pressure. The administration chamber 14 is equipped with sensors, not shown, so as to detect a possible gas leak. [Fig. 1] also shows a source 16 of liquefied gas, as well as a source 18 of a tracer gas. The installation 10 also comprises a pump 20 configured to pump and compress the liquefied gas to a pressure ranging from 500 to 1000 bars, a vaporizer 22, a compressor 24 configured to compress the tracer gas to a pressure ranging from 500 to 1000 bars, and a buffer tank 26.The liquefied gas is stored at a pressure of 10 bar in the liquefied gas source 16. In one example, the liquefied gas source 16 is a tank containing liquefied gas. Thus, the pump 20 pumps liquefied gas at a pressure of 10 bar, and compresses it to a pressure ranging from 500 to 1000 bar. The pump 20 is a cryogenic pump comprising a cold head, not shown.
[0044] The control method according to the invention comprises the following steps: a) pumping and compressing the liquefied gas by means of the pump 20 from the source 16 of liquefied gas, so as to obtain a liquefied gas compressed at a pressure ranging from 500 to 1000 bar, b) vaporizing the compressed liquefied gas obtained in step a) so as to obtain a vaporized liquefied gas, (c) compressing the tracer gas so as to obtain a compressed tracer gas at a pressure ranging from 500 to 1000 bar, d) mixing the vaporized liquefied gas obtained in step b) with the compressed tracer gas obtained in step c) in the buffer tank 26 so as to obtain a gas mixture, e) fill the high pressure tank 12 to be checked with the gas mixture obtained in step d), then f) look for a tracer gas leak on the high pressure tank 12 to be checked.
[0045] In the installation 10 shown diagrammatically in [Fig.l]: - step a) is carried out at the pump 20, - step b) is carried out at the vaporizer 22, - step c) is carried out at the compressor 24, - the search for the gas leak from step f) is carried out in the administration enclosure 14.
[0046] Preferably, step c) is carried out after steps a) and b), however, it could be carried out before or at the same time as step a) and / or step b).
[0047] In the example shown in [Fig.l], the high-pressure tank 12 is intended to contain hydrogen at high pressure. The mixing of the vaporized liquefied gas with the compressed tracer gas in the buffer tank 26 is for example carried out at a pressure ranging from 500 to 1000 bar. The liquefied gas is for example nitrogen. The mixture of vaporized liquefied gas with the tracer gas may be a mixture containing a proportion ranging from 95% to 96% by weight of nitrogen and from 4 to 5% by weight of hydrogen.
[0048] In general, before step d) of mixing gases in the buffer tank (26), a step of dosing each gas obtained in steps b) and c) so as to control the proportion of each gas in the gas mixture. Preferably, this control is carried out by a mass flow meter 28, preferably this control is carried out continuously.
[0049] [Fig. 2] schematically shows the circulation of fluids in the method for checking the tightness according to a first embodiment of the invention. In this embodiment, the pump 20 is configured to pump and compress the liquefied gas to a pressure ranging from 900 to 1000 bar, and the compressor 24 is configured to pump and compress the tracer gas to a pressure ranging from 900 to 1000 bar. The liquefied gas is pumped and compressed so as to obtain a compressed liquefied gas at a pressure ranging from 900 to 1000 bar, and the tracer gas is compressed so as to obtain a compressed tracer gas at a pressure ranging from 900 to 1000 bar. Thus in this embodiment, the mixing of the vaporized liquefied gas with the compressed tracer gas in the buffer tank 26 is carried out at a pressure ranging from 900 to 1000 bar. The installation 10 partially shown in [Fig.2] also comprises a gas analyzer 50 arranged downstream of the buffer tank 26 and upstream of the high-pressure tank to be controlled, not shown in [Fig. 2]. Thus, after step d) of mixing gas in the buffer tank 26 and before step e) of filling the tank to be controlled 12 with the gas mixture obtained in step d), the quality of the gas mixture obtained in step d) is controlled. The gas analyzer 50 is for example a chromatograph. The control of the gas proportion is managed at the level of a gas mixture control panel 30. Also shown in [Fig. 2] is a heat exchanger 32 located near the installation 10. The heat exchanger . heat exchanger 32 is itself cooled by liquefied gas circulating from the source 16 of liquefied gas, which is represented by the arrow 33. Thus, the method according to this embodiment comprises, before step e) of filling the tank to be controlled 12 with the gas mixture obtained in step d), a step of cooling the gas mixture via the heat exchanger 32. The temperature of the gas mixture required for filling the high-pressure tank is thus controlled, a temperature which must remain between -40°C and 85°C. The source 16 of liquefied gas is thus advantageously used for cooling the gas mixture.
[0050] The installation 10 shown in [Fig. 2] comprises two pumps 20 configured to pump and compress the liquefied gas so as to bring it to a pressure ranging from 900 to 1000 bar, two compressors 24 configured to compress the tracer gas to a pressure ranging from 900 to 1000 bar, two vaporizers 22. The pumps 20 are arranged on a pump support 34 (also called a “pump skid” in English) and the two compressors 24 are arranged on a compressor support 36 (also called a “compressor skid” in English). A control panel 38 for the vaporizers 22 is also shown. Thanks to the presence of the two pumps 20, the two compressors 24, and the two vaporizers 22, maintenance operations can be carried out without requiring the production line to be stopped. In fact, in each pair of devices, one of the two devices is redundant, in other words, one is used while the other is stopped.Thus, when a device must be stopped for a maintenance operation for example, the redundant device is put into service to take over from the stopped device, this makes it possible to avoid stopping the production line during a maintenance operation.
[0051] In [Fig. 2], the source 16 of liquefied gas comprises an earth connection 35, a 3G connection 37 and a power supply 39. The earth connection 35 relates to the installation 10 as a whole. In the example where the source 16 of liquefied gas is a tank containing liquefied gas, the level of liquefied gas in the tank is measured by a sensor, for example a pressure sensor. The 3G connection is a mobile Internet connection which allows the supplier of the liquefied gas to be informed of the level of liquefied gas in the tank in order to plan a filling of the tank when the level reaches a predetermined threshold, for example when the level reaches 20% of the nominal capacity of the tank.
[0052] When the installation 10 is started, the cold head of the pump 20 is at ambient temperature. To ensure proper operation of the pump 20, the cold head is brought to its optimum operating temperature (-196°C for liquid nitrogen). To do this, the cold head is supplied with subcooled liquefied gas (in the case of liquid nitrogen, this is liquid nitrogen brought to a temperature below -196°C) by means of a subcooling device, not shown. The source of liquefied gas is thus advantageously used to sub-cool the cold head of the pump 20 in order to ensure proper operation of the pump 20 when starting the installation 10.
[0053] The installation 10 of [Fig. 2] further comprises a pipe, not shown, for injecting liquefied gas from the source 16 of liquefied gas into the vaporized liquefied gas. Thus in this example, after step b) of vaporizing the liquefied gas and before step d) of mixing gas in the buffer tank 26, the method comprises a step of cooling the vaporized liquefied gas, by injecting liquefied gas from the source 16 of liquefied gas into the vaporized liquefied gas.
[0054] The installation 10 shown in [Fig.2] further comprises a gas analyzer 40 at the outlet of the compressor 24. The analyzer 40 makes it possible to detect the presence of hydrocarbons in the compressed gas, for example oil in the case where the compressor 24 is lubricated.
[0055] [Fig. 3] schematically shows the circulation of fluids in the method for checking the tightness according to a second embodiment of the invention. In this embodiment, the pump 20 is configured to pump and compress the liquefied gas to a pressure of approximately 500 bar, and the compressor 24 is configured to pump and compress the tracer gas to a pressure of approximately 500 bar. The liquefied gas is pumped and compressed so as to obtain a compressed liquefied gas at a pressure of approximately 500 bar, and the tracer gas is compressed so as to obtain a compressed tracer gas at a pressure of approximately 500 bar. Thus, in this embodiment, the mixing of the vaporized liquefied gas with the compressed tracer gas in the buffer tank 26 is carried out at a pressure of approximately 500 bar. The installation of [Fig.3] also comprises a compressor 44 capable of compressing the gas mixture stored in the buffer tank 26 so as to bring it to a pressure of approximately 1000 bar. In this embodiment, the method in fact also comprises, before step e) of filling the high-pressure tank 12 to be controlled with the gas mixture obtained in step d), a step of compressing the gas mixture obtained in step d) so as to obtain a compressed gas mixture at a pressure of approximately 1000 bar. The compressed gas mixture at approximately 1000 bar is then stored in a storage tank 46. From this storage tank 46, step e) of filling the high-pressure tank to be controlled is carried out. The installation 10 shown in [Fig. 3] comprises two compressors 44, one of which is redundant, like the two compressors 24. One of the compressors 44 is used while the other is stopped.
[0056] The installations 10 of figures 2 and 3 also include particle and oil filters 48 to allow maintenance of the installation.
[0057] The invention is not limited to the embodiments presented and other embodiments implementation will be clear to those skilled in the art. In particular, it is possible to use a tracer gas other than hydrogen, such as helium. It is also possible to use another liquefied gas. List of references
[0058] 10: installation 12: high pressure tank 14: administration enclosure 16: source of liquefied gas 18: tracer gas source 20: pump 22: vaporizer 24: compressor 26: buffer tank 28: mass flow meter 30: Gas mixture control panel 32: heat exchanger 33: circulation of liquefied gas 34: pump support 35: grounding 36: compressor support 37: 3G connection 38: Vaporizer control panel 39: power supply 40: gas analyzer 44: compressor from 400 to 1000 bar 46: storage tank 48: particulate and oil filter 50: gas analyzer
Claims
Claims
1. A method for testing the leaktightness of a high-pressure tank (12), wherein the method comprises the following steps: a) pumping and compressing a liquefied gas by means of a pump (20) from a source (16) of liquefied gas, so as to obtain a compressed liquefied gas at a pressure ranging from 500 to 1000 bar, b) vaporizing the compressed liquefied gas obtained in step a) so as to obtain a vaporized liquefied gas, c) compressing a tracer gas so as to obtain a compressed tracer gas at a pressure ranging from 500 to 1000 bar, d) mixing the vaporized liquefied gas obtained in step b) with the compressed tracer gas obtained in step c) in a buffer tank (26) so as to obtain a gas mixture e) filling the high-pressure tank (12) to be tested with the gas mixture obtained in step d), then f) look for a tracer gas leak on the high pressure tank (12) to be checked.
2. A method of testing leak tightness according to the preceding claim, wherein the liquefied gas is pumped and compressed so as to obtain a compressed liquefied gas at a pressure ranging from 900 to 1000 bar, preferably about 1000 bar, and the tracer gas is compressed so as to obtain a compressed tracer gas at a pressure ranging from 900 to 1000 bar, preferably about 1000 bar.
3. A method of testing the leaktightness according to claim 1, wherein the liquefied gas is pumped and compressed so as to obtain a compressed liquefied gas at a pressure of approximately 500 bar, the tracer gas is compressed so as to obtain a compressed tracer gas at a pressure of approximately 500 bar, the method comprises before step e) of filling the high pressure tank (12) to be tested with the gas mixture obtained in step d): - a step of compressing the gas mixture obtained in step d) so as to obtain a compressed gas mixture at a pressure of approximately 1000 bar.
4. Method for checking the leaktightness according to any one of the preceding claims, comprising before step e) of filling the high pressure tank (12) to be checked with the gas mixture obtained in step d), a step of cooling said gas mixture, preferably via a heat exchanger (32) itself cooled by liquefied gas circulating (33) from the source (16) of liquefied gas.
5. A method of testing leak tightness according to any one of the preceding claims, comprising after step b) of vaporizing the liquefied gas and before step d) of mixing gas in the buffer tank (26), a step of cooling the vaporized liquefied gas, preferably by injecting liquefied gas from the source (16) of liquefied gas into the vaporized liquefied gas.
6. A method of leak testing according to any preceding claim, wherein liquefied gas flows from the liquefied gas source (16) to a cold head of the pump.
7. A method of controlling the leaktightness according to any one of the preceding claims, comprising before step d) of mixing gases in the buffer tank (26), a step of dosing each gas obtained in steps b) and c) so as to control the proportion of each gas in the gas mixture.
8. Installation (10) for implementing a method for checking the tightness of a high-pressure tank (12) according to any one of the preceding claims, comprising: - an administration chamber (14), - a pump (20) configured to pump and compress a liquefied gas to a pressure ranging from 500 to 1000 bars, - a vaporizer (22), - a compressor (24) configured to compress a tracer gas to a pressure ranging from 500 to 1000 bars, - a buffer tank (26).
9. Installation (10) according to the preceding claim, comprising two pumps (20) configured to pump and compress the liquefied gas to a pressure ranging from 500 to 1000 bars, and / or comprising two compressors (24) configured to compress the tracer gas to a pressure ranging from 500 to 1000 bars, and / or comprising two vaporizers (22).
10. Installation (10) according to any one of claims 8 and 9, in which a cold head of the pump (20) comprises a device for the circulation of the liquefied gas from the source (16) of liquefied gas.
11. Installation (10) according to any one of claims 8 to 10, further comprising a gas analyzer (50) arranged downstream of the buffer tank (26) and upstream of the high pressure tank (12) to be controlled.
12. An installation (10) according to any one of claims 8 to 11, further comprising a conduit for injecting liquefied gas from the source (16) of liquefied gas into the vaporized liquefied gas.