EP0706632A1 - Method for producing very low temperatures - Google Patents

Method for producing very low temperatures

Info

Publication number
EP0706632A1
EP0706632A1 EP94921676A EP94921676A EP0706632A1 EP 0706632 A1 EP0706632 A1 EP 0706632A1 EP 94921676 A EP94921676 A EP 94921676A EP 94921676 A EP94921676 A EP 94921676A EP 0706632 A1 EP0706632 A1 EP 0706632A1
Authority
EP
European Patent Office
Prior art keywords
mixture
temperature
enclosure
point
joule
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP94921676A
Other languages
German (de)
French (fr)
Other versions
EP0706632B1 (en
Inventor
Alain Daniel Benoit
Serge Pujol
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Centre National dEtudes Spatiales CNES
Original Assignee
Centre National dEtudes Spatiales CNES
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Centre National dEtudes Spatiales CNES filed Critical Centre National dEtudes Spatiales CNES
Publication of EP0706632A1 publication Critical patent/EP0706632A1/en
Application granted granted Critical
Publication of EP0706632B1 publication Critical patent/EP0706632B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/12—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point using 3He-4He dilution

Definitions

  • the present invention relates to a method and a device for obtaining very low temperatures, less than about 1 ° K, and in particular 0.1 C K.
  • the document EP-A-0327.457 which corresponds to US-A-4,991,401 and which cites as inventor one of the authors of the present invention, describes a cryostat which comprises a mixing point in which a two-phase system comprising a solution phase of 3He in 4He liquid and a liquid phase formed of pure 3He. 3He and liquid 4He are continuously introduced into a mixing point separately, and the solution is extracted from the mixing point at a speed such that 3He cannot go back to raise the 3He content of 4He and consequently making it less capable of dissolving the liquid 3He introduced.
  • a mixing point is placed in an enclosure brought to within 2 ° K.
  • the two fluids by mixing create a two-phase system comprising a phase rich in 3He and a diluted phase, the energy of dilution or dissolution being used for cooling, the succession of the two phases in the mixture outlet tube prevents the diffusion of the 3He dissolved against the current in the cold part of the system, while at higher temperature (above 0.5 K), the solubility of 3He in the 4He increases, the mixture has only one single phase and the speed must be sufficient so that the 3He cannot diffuse against the current.
  • This cryostat has the advantage of being able to operate in the absence of gravity because it does not include a distiller, which makes it particularly advantageous for space uses.
  • the cryostat can operate by rejecting into space the small amounts of mixture of 4He and 3He that it produces. In case the vehicle has to return to the ground, this mixture can also be stored in a tank, with a view to distilling it on the ground. If the cryostat is used on land, it can, of course, be coupled with a distillation installation, the assembly then operating in a closed circuit.
  • a difficulty encountered in the use of this cryostat results from the need to have a superfluid helium reservoir to maintain the enclosure at less than 2 ° K, which is a complication.
  • the present invention aims to provide a cryostat operating according to the method described in EP-A-0327.457 and which has a simple construction, is space-saving, and consumes little energy, and more especially is freed from the need to produce and / or store superfluid helium to cool the enclosure to 2 ° K or less.
  • the invention provides a process for obtaining very low temperatures according to which 4He and 3He are continuously introduced, which are cooled using heat exchangers at a temperature of the order of 0.2 ° K or less, at the point where they are mixed to absorb heat by diluting the 3He in 4He, thus cooling the closed two-phase mixture, which mixture is extracted through a conduit designed so that 3He cannot diffuse against the current and reduce the dissolution of 3He, a process in which an adjacent heat exchanger at the mixing point is used for cooling fluids going to the coldest point by the extracted mixture circulating in opposite directions, the main feature of this process being that the 4He and 3He intended to be mixed are cooled down to their temperature supply at a temperature below 2.5 ° K by exchange with the extracted mixture, the power being absorbed by the use of a Joule-Thomson expansion of this mixture, thus allowing the system to operate with a temperature of food well above 4 ° K.
  • the cooling power during the Joule-Thomson expansion depends only on the inlet and outlet pressures of the mixture. The best performances are obtained for pressures of the order of 2 to 15 bars at the inlet and from 1 to 50 millibars at the outlet.
  • FIG. 1 is a theoretical diagram of the installation of the prior art
  • FIG. 2 is a theoretical diagram of an installation in accordance with the invention
  • FIG. 3 is an enthalpy diagram of helium 4 on which the important points of the diagram of FIG. 2 have been transferred.
  • Figure 1 shows the block diagram of a practical embodiment which operates in accordance with the indications of the document EP-A-0327.457 cited above.
  • Pure 4He gas and 3He gas are injected under pressure (about 3 bars) and at room temperature, each in a heat exchanger 1, in contact with a superfluid helium reserve, symbolized in 2, which also carries the enclosure 3 of the cryostat, and are cooled to approximately 2 ° K.
  • the two fluids are then cooled in a temperature exchanger 4, then the heat absorbed by their mixing in a mixing chamber 5 makes it possible to cool a support 6 to a temperature of the order of 0.1 ° K.
  • the mixture M absorbs heat in the exchanger 4 before leaving the cryostat at an outlet pressure maintained at around 2 bars. The pressure difference with the inlet pressure is due to the pressure drop in the exchangers.
  • the exchanger 4 comprises two parts, the hot part (0.5 ° K to 2 ° K) of 1 meter in length is composed of three tubes of 0.03 mm inside diameter, welded together, while that the cold part (0.1 ° K to 0.5 ° K) is formed by three tubes of 0.02 mm in diameter and 3 meters long welded together.
  • FIG 2 is a schematic view of the device of Figure 1 modified according to the invention.
  • the same references designate the same elements.
  • Pure 4He and 3He gases are injected under pressure (between 2 and 20 bars) and at room temperature. They are then cooled to between 4 ° K and 10 ° K by exchangers 10, themselves coupled to an annex precooling machine 11. Penetrating into an external enclosure 13, the fluids are cooled to a temperature of the order of 2 ° K by the exchangers 12, themselves coupled to an intermediate enclosure 3. The interior of this enclosure is identical to that of FIG. 1.
  • the mixture At the outlet of the exchanger 4, the mixture has undergone a pressure drop and is found at low pressure in an exchanger 14 where the liquid is evaporated, providing a large cooling power which is used to cool the screen limiting the enclosure 13, as well as the fluids entering through the exchangers 12.
  • the mixture 11 then leaves the cryostat at low pressure (between 1 and 50 millibars) through a tube 15.
  • FIG. 3 which represents an enthalpy diagram of helium 4, makes it possible to understand the physical aspect of the phenomena which occur inside the apparatus.
  • This diagram relates to pure helium 4, while helium 4 and helium 3 are used either separately or as a mixture.
  • the proportion of helium 3 compared to helium 4 is relatively low, around 20%, so that the diagram in Figure 3 still gives a fairly good idea of what sits.
  • the enthalpy is 50 J / mole. If the outlet pressure is fixed at 30 millibars, the fluid retains its enthalpy and is found at point B at a temperature of 2 ° K, with a two-phase mixture half vapor, half liquid.
  • the available cooling power is given by the difference in enthalpy between points B and C, ie about 50 J / mole. For a typical flow rate of 10 ⁇ moles / s, the power available on enclosure 3 is therefore 0.5 mW. For an inlet temperature above 7 ° K, the same reasoning leads to zero available power.
  • the quantities of gas required are 1000 liters per year of helium 3 and 4000 liters per year of helium 4. If we use standard high pressure bottles (volume 5 liters, pressure 200 bars, weight 6.7 kg), the cryostat only needs one bottle of helium 3 and four bottles of helium 4 per year, which corresponds at 33.5 kg per year. This weight can be easily reduced by using high pressure cylinders made of more resistant materials.
  • the simplicity of the system allows very simple control by adjusting the flow rates of the two fluids at the inlet of the cryostat. This allows the dilution to be stopped and restarted to optimize the consumption of helium gas.

Abstract

Temperatures of 0.2 °K or lower are achieved by feeding 3He and 4He separately into a mixing chamber (5) in an enclosure (3) in which the temperature is held at around 2 °K. The endothermal dilution of 3He into 4He provides the required cold. The resulting mixture (M) passes out of the mixing chamber and the enclosure while cooling the incoming fluids by means of exchangers (1, 12, 4). To compensate for thermal losses, the mixture (M) also undergoes Joule-Thomson expansion (12) optionally followed by evaporation (13), preferably between about 1.5 and 2.5 °K, and the resulting cold is used to lower the temperature of the incoming fluids from well above 4 °K to between 1.5 and 2.5 °K, which is close to the temperature prevailing inside the enclosure (13) containing the coldest point (6) in the circuit.

Description

Procédé d'obtention de très basses températures.Process for obtaining very low temperatures.
La présente invention est relative à un procédé et un dispositif pour obtenir de très basses températures, inférieures à 1°K environ, et notamment à 0,1CK.The present invention relates to a method and a device for obtaining very low temperatures, less than about 1 ° K, and in particular 0.1 C K.
Le document EP-A-0327.457, qui correspond au brevet US-A-4.991.401 et qui cite comme inventeur un des auteurs de la présente invention, décrit un cryostat qui comprend un point de mélange dans lequel on entretien un système diphasique comprenant une phase de solution de 3He dans 4He liquide et une phase de liquide formée de 3He pur. On introduit en continu dans un point de mélange, séparément, du 3He et du 4He liquide, et on extrait la solution du point de mélange à une vitesse telle que le 3He ne puisse pas revenir en arrière pour élever la teneur en 3He du 4He et le rendre par conséquent moins apte à dissoudre le 3He liquide introduit. Un point de mélange est placée dans une enceinte portée à moins de 2°K.The document EP-A-0327.457, which corresponds to US-A-4,991,401 and which cites as inventor one of the authors of the present invention, describes a cryostat which comprises a mixing point in which a two-phase system comprising a solution phase of 3He in 4He liquid and a liquid phase formed of pure 3He. 3He and liquid 4He are continuously introduced into a mixing point separately, and the solution is extracted from the mixing point at a speed such that 3He cannot go back to raise the 3He content of 4He and consequently making it less capable of dissolving the liquid 3He introduced. A mixing point is placed in an enclosure brought to within 2 ° K.
Plus précisément, dans le point de mélange, les deux fluides en se mélangeant créent un système diphasique comprenant une phase riche en 3He et une phase diluée, l'énergie de dilution ou de mise en solution étant utilisée pour le refroidissement, la succession des deux phases dans le tube de sortie du mélange empêche la diffusion du 3He dissous à contre-courant dans la partie froide du système, tandis qu'à plus haute température (au- dessus de 0,5 K), la solubilité du 3He dans le 4He augmente, le mélange ne comporte plus qu'une seule phase et la vitesse doit être suffisante pour que le 3He ne puisse pas diffuser à contre-courant.More precisely, in the mixing point, the two fluids by mixing create a two-phase system comprising a phase rich in 3He and a diluted phase, the energy of dilution or dissolution being used for cooling, the succession of the two phases in the mixture outlet tube prevents the diffusion of the 3He dissolved against the current in the cold part of the system, while at higher temperature (above 0.5 K), the solubility of 3He in the 4He increases, the mixture has only one single phase and the speed must be sufficient so that the 3He cannot diffuse against the current.
Ce cryostat présente l'avantage de pouvoir fonctionner en 1'absence de gravité car il ne comprend pas de distillateur, ce qui le rend particulièrement avantageux pour des utilisations spatiales. Dans de telles utilisation, le cryostat peut fonctionner en rejetant dans l'espace les faibles quantités de mélange de 4He et 3He qu'il produit. Au cas où le véhicule doit revenir à terre, on peut aussi stocker ce mélange dans un réservoir, en vue de le distiller au sol. Si le cryostat est utilisé à terre, il pourra, bien entendu, être couplé avec une installation de distillation, l'ensemble fonctionnant alors en circuit fermé.This cryostat has the advantage of being able to operate in the absence of gravity because it does not include a distiller, which makes it particularly advantageous for space uses. In such use, the cryostat can operate by rejecting into space the small amounts of mixture of 4He and 3He that it produces. In case the vehicle has to return to the ground, this mixture can also be stored in a tank, with a view to distilling it on the ground. If the cryostat is used on land, it can, of course, be coupled with a distillation installation, the assembly then operating in a closed circuit.
Une difficulté rencontrée dans l'utilisation de ce cryostat résulte de la nécessité d'avoir un réservoir d'hélium superfluide pour maintenir l'enceinte à moins de 2°K, ce qui est une complication. On sait qu'un tel stockage impose des sujétions particulières, difficiles à remplir notamment à bord d'un vaisseau spatial. La présente invention a pour but de fournir un cryostat fonctionnant selon le procédé décrit dans EP-A- 0327.457 et qui présente une construction simple, soit peu encombrant, et consomme peu d'énergie, et plus spécialement soit affranchi de la nécessité de produire et/ou stocker de l'hélium superfluide pour refroidir l'enceinte à 2°K ou moins.A difficulty encountered in the use of this cryostat results from the need to have a superfluid helium reservoir to maintain the enclosure at less than 2 ° K, which is a complication. We know that such storage imposes special constraints, difficult to fill in particular on board a spacecraft. The present invention aims to provide a cryostat operating according to the method described in EP-A-0327.457 and which has a simple construction, is space-saving, and consumes little energy, and more especially is freed from the need to produce and / or store superfluid helium to cool the enclosure to 2 ° K or less.
Pour obtenir ce résultat, l'invention fournit un procédé d'obtention de très basses températures selon lequel on introduit en continu du 4He et du 3He que 1'on refroidit à l'aide d'echangeurs de chaleur à température de l'ordre de 0,2°K ou inférieure, dans le point où on les mélange pour absorber de la chaleur par la dilution du 3He dans le 4He, produisant ainsi un refroidissement du mélange diphasique fermé, lequel mélange est extrait à travers un conduit conçu pour que le 3He ne puisse pas diffuser à contre-courant et réduire la dissolution du 3He, procédé dans lequel un échangeur de chaleur adjacent au point de mélange est utilisé pour le refroidissement des fluides se dirigeant vers le point le plus froid par le mélange extrait circulant en sens opposé, la particularité principale de ce procédé étant que le 4He et le 3He destinés à être mélangés sont refroidis de leur température d'alimentation à une température inférieure à 2,5°K par échange avec le mélange extrait, la puissance étant absorbée par l'utilisation d'une expansion Joule- Thomson de ce mélange, permettant ainsi au système de fonctionner avec une température d'alimentation bien supérieure à 4°K.To obtain this result, the invention provides a process for obtaining very low temperatures according to which 4He and 3He are continuously introduced, which are cooled using heat exchangers at a temperature of the order of 0.2 ° K or less, at the point where they are mixed to absorb heat by diluting the 3He in 4He, thus cooling the closed two-phase mixture, which mixture is extracted through a conduit designed so that 3He cannot diffuse against the current and reduce the dissolution of 3He, a process in which an adjacent heat exchanger at the mixing point is used for cooling fluids going to the coldest point by the extracted mixture circulating in opposite directions, the main feature of this process being that the 4He and 3He intended to be mixed are cooled down to their temperature supply at a temperature below 2.5 ° K by exchange with the extracted mixture, the power being absorbed by the use of a Joule-Thomson expansion of this mixture, thus allowing the system to operate with a temperature of food well above 4 ° K.
La puissance de refroidissement lors de l'expansion Joule-Thomson ne dépend que des pressions d'entrée et de sortie du mélange. Les meilleures performances sont obtenues pour des pressions de l'ordre de 2 à 15 bars en entrée et de 1 à 50 millibars en sortie.The cooling power during the Joule-Thomson expansion depends only on the inlet and outlet pressures of the mixture. The best performances are obtained for pressures of the order of 2 to 15 bars at the inlet and from 1 to 50 millibars at the outlet.
L'invention résulte de la constatation que, par une utilisation judicieuse de la détente Joule-Thomson des fluides utilisés pour le procédé de refroidissement à très basse température, il est possible de pré-refroidir les fluides entrant dans le système à partir d'une température beaucoup plus élevée, de l'ordre de 4 à 10°K, permettant de s'affranchir des installations auxiliaires de pré¬ refroidissement nécessaires dans l'art antérieur, et en particulier de bain d'hélium superfluide. Les températures de 4 à 10°K sont facilement obtenues à l'aide d'une machine cryogénique Stirling suivie d'une étape Joule- Thomson classique à 4He liquide. 'invention va maintenant être expliquée de façon plus détaillée à l'aide d'exemples pratiques, illustrés à l'aide des figures, parmi lesquelles : Figure 1 est un schéma théorique de 1'installation de 1'art antérieur,The invention results from the observation that, by judicious use of the Joule-Thomson expansion of the fluids used for the very low temperature cooling process, it is possible to pre-cool the fluids entering the system from a much higher temperature, of the order of 4 to 10 ° K, making it possible to dispense with the auxiliary pre-cooling installations necessary in the prior art, and in particular of superfluid helium bath. Temperatures from 4 to 10 ° K are easily obtained using a Stirling cryogenic machine followed by a classic Joule-Thomson step with liquid 4He. The invention will now be explained in more detail with the aid of practical examples, illustrated with the aid of the figures, among which: FIG. 1 is a theoretical diagram of the installation of the prior art,
Figure 2 est un schéma théorique d'une installation conforme à l'invention, Figure 3 est un diagramme enthalpique de 1'hélium 4 sur lequel on a reporté les points importants du schéma de la figure 2.FIG. 2 is a theoretical diagram of an installation in accordance with the invention, FIG. 3 is an enthalpy diagram of helium 4 on which the important points of the diagram of FIG. 2 have been transferred.
La figure 1 montre le schéma de principe d'une réalisation pratique qui fonctionne conformément aux indications du document EP-A-0327.457 cité plus haut.Figure 1 shows the block diagram of a practical embodiment which operates in accordance with the indications of the document EP-A-0327.457 cited above.
Du gaz 4He et du gaz 3He purs sont injectés sous pression (environ 3 bars) et à température ambiante, chacun dans un échangeur de chaleur 1, en contact avec une réserve d'hélium superfluide, symbolisée en 2, qui porte aussi l'enceinte 3 du cryostat, et sont refroidis à 2°K environ. Les deux fluides sont alors refroidis dans un échangeur de température 4, puis la chaleur absorbée par leur mélange dans une chambre de mélange 5 permet de refroidir un support 6 à une température de 1'ordre de 0,1°K. Le mélange M absorbe de la chaleur dans l'echangeur 4 avant de sortir du cryostat à une pression de sortie maintenue aux environs de 2 bars. La différence de pression avec celle d'entrée est due à la perte de charge dans les échangeurs. Dans la réalisation pratique, l'echangeur 4 comprend deux parties, la partie chaude (0,5°K à 2°K) de 1 mètre de longueur est composée de trois tubes de 0,03 mm de diamètre intérieur, soudés ensembles, tandis que la partie froide (0,1°K à 0,5°K) est formée de trois tubes de 0,02 mm de diamètre et de 3 mètres de long soudés ensemble.Pure 4He gas and 3He gas are injected under pressure (about 3 bars) and at room temperature, each in a heat exchanger 1, in contact with a superfluid helium reserve, symbolized in 2, which also carries the enclosure 3 of the cryostat, and are cooled to approximately 2 ° K. The two fluids are then cooled in a temperature exchanger 4, then the heat absorbed by their mixing in a mixing chamber 5 makes it possible to cool a support 6 to a temperature of the order of 0.1 ° K. The mixture M absorbs heat in the exchanger 4 before leaving the cryostat at an outlet pressure maintained at around 2 bars. The pressure difference with the inlet pressure is due to the pressure drop in the exchangers. In the practical embodiment, the exchanger 4 comprises two parts, the hot part (0.5 ° K to 2 ° K) of 1 meter in length is composed of three tubes of 0.03 mm inside diameter, welded together, while that the cold part (0.1 ° K to 0.5 ° K) is formed by three tubes of 0.02 mm in diameter and 3 meters long welded together.
La figure 2 est une vue schématique du dispositif de la figure 1 modifié conformément à l'invention. Sur les deux figures, les mêmes références désignent les mêmes éléments.Figure 2 is a schematic view of the device of Figure 1 modified according to the invention. In the two figures, the same references designate the same elements.
Des gaz 4He et 3He purs sont injectés sous pression (entre 2 et 20 bars) et à température ambiante. Ils sont ensuite refroidis entre 4°K et 10°K par des échangeurs 10, eux-mêmes couplés à une machine annexe de prérefroidissement 11. Pénétrant dans une enceinte extérieure 13, les fluides sont refroidis à une température de l'ordre de 2°K par les échangeurs 12, eux- mêmes couplés à une enceinte intermédiaire 3. L'intérieur de cette enceinte est iàentique à celui de la figure 1.Pure 4He and 3He gases are injected under pressure (between 2 and 20 bars) and at room temperature. They are then cooled to between 4 ° K and 10 ° K by exchangers 10, themselves coupled to an annex precooling machine 11. Penetrating into an external enclosure 13, the fluids are cooled to a temperature of the order of 2 ° K by the exchangers 12, themselves coupled to an intermediate enclosure 3. The interior of this enclosure is identical to that of FIG. 1.
A la sortie de l'echangeur 4, le mélange a subi une perte de charge et se retrouve à basse pression dans un échangeur 14 où le liquide est évaporé, fournissant un grand pouvoir réfrigérant qui est utilisé pour refroidir l'écran limitant l'enceinte extérieure 13, ainsi que les fluides entrant par les échangeurs 12. Le mélange 11 quitte ensuite le cryostat à basse pression (entre 1 et 50 millibars) par un tube 15.At the outlet of the exchanger 4, the mixture has undergone a pressure drop and is found at low pressure in an exchanger 14 where the liquid is evaporated, providing a large cooling power which is used to cool the screen limiting the enclosure 13, as well as the fluids entering through the exchangers 12. The mixture 11 then leaves the cryostat at low pressure (between 1 and 50 millibars) through a tube 15.
La figure 3, qui représente un diagramme enthalpique de 1'hélium 4 permet de comprendre 1'aspect physique des phénomènes qui se produisent à l'intérieur de l'appareil. Ce diagramme est relatif à de l'hélium 4 pur, alors qu'on utilise de l'hélium 4 et de l'hélium 3 soit séparément, soit en mélange. Dans la pratique, la proportion d'hélium 3 par rapport à l'hélium 4 est relativement faible, environ 20%, si bien que le diagramme de la figure 3 donne quand même une assez bonne idée d'ensemble de ce qui se asse.FIG. 3, which represents an enthalpy diagram of helium 4, makes it possible to understand the physical aspect of the phenomena which occur inside the apparatus. This diagram relates to pure helium 4, while helium 4 and helium 3 are used either separately or as a mixture. In practice, the proportion of helium 3 compared to helium 4 is relatively low, around 20%, so that the diagram in Figure 3 still gives a fairly good idea of what sits.
Pour une pression d'entrée de 9 bars et une température de 4°K par exemple (point A), l'enthalpie est de 50 J/mole. Si la pression de sortie est fixée à 30 millibars, le fluide conserve son enthalpie et se retrouve au point B à une température de 2°K, avec un mélange diphasique moitié vapeur, moitié liquide. La puissance de refroidissement disponible est donnée par la différence d'enthalpie entre les points B et C, soit environ 50 J/mole. Pour un débit typique de 10 μmoles/s, la puissance disponible sur l'enceinte 3 est donc de 0,5 mW. Pour une température d'entrée supérieure à 7°K, le même raisonnement conduit à une puissance disponible nulle. Il faut alors ajouter un échangeur de chaleur continu entre les tubes d'entrée connectant les échangeurs 10 et 12 et le tube de sortie 15. L'utilisation d'un tel échangeur couplé à une détente Joule-Thomson est un procédé bien connu qui permet de faire fonctionner une telle détente avec une température de départ supérieure (jusqu'à 10°K ou 20°K).For an inlet pressure of 9 bars and a temperature of 4 ° K for example (point A), the enthalpy is 50 J / mole. If the outlet pressure is fixed at 30 millibars, the fluid retains its enthalpy and is found at point B at a temperature of 2 ° K, with a two-phase mixture half vapor, half liquid. The available cooling power is given by the difference in enthalpy between points B and C, ie about 50 J / mole. For a typical flow rate of 10 μmoles / s, the power available on enclosure 3 is therefore 0.5 mW. For an inlet temperature above 7 ° K, the same reasoning leads to zero available power. he must then add a continuous heat exchanger between the inlet tubes connecting the exchangers 10 and 12 and the outlet tube 15. The use of such an exchanger coupled to a Joule-Thomson expansion is a well known process which allows to operate such a trigger with a higher flow temperature (up to 10 ° K or 20 ° K).
Avec les débits utilisés ( 1,5 μmole/s de 3He et 6 μmole/s de 4He), les quantités de gaz nécessaires sont de 1000 litres par an d'hélium 3 et 4000 litres par an d'hélium 4. Si nous utilisons des bouteilles standard à haute pression (volume 5 litres, pression 200 bars, poids 6,7 kg), le cryostat n'a besoin que d'une bouteille d'hélium 3 et quatre bouteilles d'hélium 4 par an, ce qui correspond à 33,5 kg par an. Ce poids peut être réduit aisément en utilisant des bouteilles haute pression faites en des matériaux plus résistants.With the flow rates used (1.5 μmol / s of 3He and 6 μmol / s of 4He), the quantities of gas required are 1000 liters per year of helium 3 and 4000 liters per year of helium 4. If we use standard high pressure bottles (volume 5 liters, pressure 200 bars, weight 6.7 kg), the cryostat only needs one bottle of helium 3 and four bottles of helium 4 per year, which corresponds at 33.5 kg per year. This weight can be easily reduced by using high pressure cylinders made of more resistant materials.
Comme tous les fluides sont confinés dans des petits tubes et qu'il n'y a pas de surface libre de séparation de base, le système est insensible à la gravité.Since all fluids are confined in small tubes and there is no free basic separation surface, the system is insensitive to gravity.
La simplicité du système permet une commande très simple par ajustement des débits des deux fluides à l'entrée du cryostat. Cela permet d'arrêter et de faire repartir la dilution pour optimiser la consommation d'hélium gazeux.The simplicity of the system allows very simple control by adjusting the flow rates of the two fluids at the inlet of the cryostat. This allows the dilution to be stopped and restarted to optimize the consumption of helium gas.
Avec cette structure, il est possible de refroidir des détecteurs, par exemple jusqu'à une température de 0,1°K dans un satellite, utilisant un petit cryogénérateur absorbant une puissance de quelques milliwatts à une température de 5°K. Le procédé est très fiable ne comportant pas de pièces mécaniques, et son utilisation exige de l'ordre de 5000 litres de gaz par an. Le dispositif est donc bien adapté pou des expériences de longue durée, dans l'espace notamment. With this structure, it is possible to cool detectors, for example to a temperature of 0.1 ° K in a satellite, using a small cryogenerator absorbing a power of a few milliwatts at a temperature of 5 ° K. The process is very reliable with no mechanical parts, and its use requires around 5000 liters of gas per year. The device is therefore well suited for long-term experiments, especially in space.

Claims

REVENDICATIONS
1. Procédé d'obtention de très basses températures selon lequel on introduit en continu du 4He et du 3He que l'on refroidit à l'aide d'echangeurs de chaleur à température de l'ordre de 0,2°K ou inférieure, dans le point (5) où on les mélange pour absorber de la chaleur par la dilution du 3He dans le 4He, produisant ainsi un refroidissement du mélange diphasique fermé, lequel mélange (M) est extrait à travers un conduit conçu pour que le 3He ne puisse pas diffuser à contre-courant et réduire la dissolution du 3He, procédé dans lequel un échangeur de chaleur (4) adjacent au point de mélange (5) est utilisé pour le refroidissement des fluides se dirigeant vers le point le plus froid par le mélange extrait (M) circulant en sens opposé, caractérisé en ce que le 4He et le 3He destinés à être mélangés sont refroidis de leur température d'alimentation à une température inférieure à 2,5°K par échange avec le mélange extrait, la puissance étant absorbée par l'utilisation d'une expansion Joule-Thomson de ce mélange, permettant ainsi au système de fonctionner avec une température d'alimentation bien supérieure à 4°K.1. A process for obtaining very low temperatures according to which 4He and 3He are continuously introduced and which are cooled using heat exchangers at a temperature of the order of 0.2 ° K or lower, in point (5) where they are mixed to absorb heat by diluting 3He in 4He, thus producing a cooling of the closed two-phase mixture, which mixture (M) is extracted through a duct designed so that 3He does not cannot diffuse against the current and reduce the dissolution of 3He, a process in which a heat exchanger (4) adjacent to the mixing point (5) is used to cool the fluids going to the coldest point by the mixture extract (M) circulating in opposite directions, characterized in that the 4He and 3He intended to be mixed are cooled from their supply temperature to a temperature below 2.5 ° K by exchange with the extracted mixture, the power being absorbed by the use of a Joule-Thomson expansion of this mixture, thus allowing the system to operate with a supply temperature well above 4 ° K.
2. Procédé selon la revendication 1, caractérisé en ce que 1'expansion Joule-Thomson se traduit par une baisse de pression jusqu'à environ 1 à 50 mb, la pression d'alimentation de 4He et de 3He étant d'environ 2 à 15 bars2. Method according to claim 1, characterized in that the Joule-Thomson expansion results in a pressure drop up to about 1 to 50 mb, the supply pressure of 4He and 3He being about 2 to 15 bars
3. Procédé selon la revendication 1 ou 2, caractérisé en ce que l'expansion et une éventuelle vaporisation consécutive du mélange sont effectuées entre 1,5 et 2,5°K environ.3. Method according to claim 1 or 2, characterized in that the expansion and possible subsequent vaporization of the mixture are carried out between 1.5 and 2.5 ° K approximately.
4. Procédé selon 1'une des revendications 1 à 3, caractérisé en ce que le point de mélange (5) et l'echangeur adjacent (4) sont placés dans une enceinte (13) maintenue à une température inférieure à 2,5°K. 4. Method according to one of claims 1 to 3, characterized in that the mixing point (5) and the adjacent exchanger (4) are placed in an enclosure (13) maintained at a temperature below 2.5 ° K.
EP94921676A 1993-07-05 1994-07-04 Method for producing very low temperatures Expired - Lifetime EP0706632B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9308201A FR2707375B1 (en) 1993-07-05 1993-07-05 Process for obtaining very low temperatures.
FR9308201 1993-07-05
PCT/FR1994/000818 WO1995002158A1 (en) 1993-07-05 1994-07-04 Method for producing very low temperatures

Publications (2)

Publication Number Publication Date
EP0706632A1 true EP0706632A1 (en) 1996-04-17
EP0706632B1 EP0706632B1 (en) 1998-03-25

Family

ID=9448906

Family Applications (1)

Application Number Title Priority Date Filing Date
EP94921676A Expired - Lifetime EP0706632B1 (en) 1993-07-05 1994-07-04 Method for producing very low temperatures

Country Status (8)

Country Link
US (1) US5657635A (en)
EP (1) EP0706632B1 (en)
JP (1) JP3304978B2 (en)
AT (1) ATE164441T1 (en)
DE (1) DE69409236T2 (en)
FR (1) FR2707375B1 (en)
RU (1) RU2117883C1 (en)
WO (1) WO1995002158A1 (en)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB0421111D0 (en) * 2004-09-22 2004-10-27 Oxford Instr Superconductivity Cryogenic flow valve system
FR2934674A1 (en) * 2008-07-31 2010-02-05 Air Liquide REFRIGERATOR AND METHOD FOR PRODUCING VERY LOW TEMPERATURE COLD
DE102009025544B3 (en) * 2009-06-19 2010-09-23 Institut für Luft- und Kältetechnik gGmbH Solution cooling machine for cooling detector of astronomical device, has chamber comprising geometry in which middle area has large volume, where gaps between bodies and walls of chamber and/or still move phases between walls and bodies
US8991150B2 (en) 2012-07-27 2015-03-31 Board Of Trustees Of Northern Illinois University High specific impulse superfluid and nanotube propulsion device, system and propulsion method
US10240875B2 (en) * 2014-07-09 2019-03-26 The Regents Of The University Of California Active cryogenic electronic envelope

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2322337A1 (en) * 1975-08-26 1977-03-25 Air Liquide REFRIGERANT SUPPLY DEVICE FOR AN OPEN CIRCUIT REFRIGERATOR, AND REFRIGERATION SYSTEM INCLUDING SUCH A DEVICE
US4080802A (en) * 1976-07-14 1978-03-28 International Telephone And Telegraph Corporation Hybrid gas cryogenic cooler
DE3435229A1 (en) * 1984-09-26 1986-04-03 Kernforschungszentrum Karlsruhe Gmbh, 7500 Karlsruhe CRYSTATE FOR OPERATING A (ARROW UP) 3 (ARROW UP) HE (ARROW UP) 4 (ARROW UP) HE MIXING UNIT
SU1229528A1 (en) * 1984-10-15 1986-05-07 Всесоюзный научно-исследовательский институт гелиевой техники Method of starting 3he - 4he refrigerator
US4697425A (en) * 1986-04-24 1987-10-06 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Oxygen chemisorption cryogenic refrigerator
FR2626658B1 (en) * 1988-02-03 1990-07-20 Centre Nat Etd Spatiales PROCESS AND APPARATUS FOR OBTAINING VERY LOW TEMPERATURES
DE3941314A1 (en) * 1989-12-14 1991-06-20 Bodenseewerk Geraetetech COOLING DEVICE
US5063747A (en) * 1990-06-28 1991-11-12 United States Of America As Represented By The United States National Aeronautics And Space Administration Multicomponent gas sorption Joule-Thomson refrigeration
US5119637A (en) * 1990-12-28 1992-06-09 The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration Ultra-high temperature stability Joule-Thomson cooler with capability to accommodate pressure variations

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9502158A1 *

Also Published As

Publication number Publication date
US5657635A (en) 1997-08-19
WO1995002158A1 (en) 1995-01-19
JP3304978B2 (en) 2002-07-22
FR2707375A1 (en) 1995-01-13
JPH08512398A (en) 1996-12-24
DE69409236D1 (en) 1998-04-30
DE69409236T2 (en) 1998-11-05
RU2117883C1 (en) 1998-08-20
FR2707375B1 (en) 1995-09-22
EP0706632B1 (en) 1998-03-25
ATE164441T1 (en) 1998-04-15

Similar Documents

Publication Publication Date Title
US20050274142A1 (en) Cryogenically producing oxygen-enriched liquid and/or gaseous oxygen from atmospheric air
KR101585825B1 (en) Hydrogen liquefaction apparatus using dual tube type heat pipe
FR3086993A1 (en) LIQUEFIED HYDROGEN STORAGE AND DISTRIBUTION SYSTEM AND APPARATUS
EP3350501A1 (en) Liquefied-fluid storage tank
EP0706632B1 (en) Method for producing very low temperatures
WO2019215403A1 (en) Method and facility for storing and distributing liquefied hydrogen
EP0188976B1 (en) Dilution cryostat
KR102282181B1 (en) Gas liquefaction apparatus
US20140000288A1 (en) Apparatus for storing hydrogen and magnetic energy and a method for the operation of said apparatus
EP2307823B1 (en) Refrigerator, and method for producing very low temperature cold
FR2775518A1 (en) PROCESS AND INSTALLATION FOR REFRIGERATED PRODUCTION FROM A THERMAL CYCLE OF A FLUID WITH LOW BOILING POINT
EP1146300B1 (en) Thermosiphon boiler-condenser
WO2022022920A1 (en) Facility and method for refrigerating a fluid
EP0327457B1 (en) Method and equipment for producing very low temperatures
FR3125115A1 (en) Hydrogen liquefaction plant and process.
JP3720701B2 (en) Jules Thomson cooling device
KR20200073956A (en) Direct type liquefaction system and liquefaction process
FR2840971A1 (en) Storage of compressible fluid in gaseous form in storage tank involves supplying temperature and pressure lower than final conditions to obtain denser, cooled fluid, which is released as gas into storage tank to fill it
RU2193740C1 (en) Gas liquefying apparatus
Bowman Jr et al. Characterizations of prototype sorption cryocoolers for the periodic formation of liquid and solid hydrogen
FR2558578A1 (en) Evaporator for a solar refrigeration installation and refrigeration method using this evaporator.
KR20230173880A (en) CO2 liquefier
FR2793312A1 (en) COUNTER-CURRENT THERMAL EXCHANGE APPARATUS AND ITS APPLICATION TO AIR DISTILLATION INSTALLATIONS
FR2481429A1 (en) Rapid drink cooling machine - includes refrigerator with evaporator passing through water tank which also contains helical coils carrying drink
FR3136540A3 (en) Installation and process for producing a cryogenic fluid

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19960115

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

17Q First examination report despatched

Effective date: 19970527

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AT BE CH DE DK ES FR GB GR IE IT LI LU MC NL PT SE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980325

Ref country code: ES

Free format text: THE PATENT HAS BEEN ANNULLED BY A DECISION OF A NATIONAL AUTHORITY

Effective date: 19980325

Ref country code: AT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980325

REF Corresponds to:

Ref document number: 164441

Country of ref document: AT

Date of ref document: 19980415

Kind code of ref document: T

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REF Corresponds to:

Ref document number: 69409236

Country of ref document: DE

Date of ref document: 19980430

ITF It: translation for a ep patent filed

Owner name: BIANCHETTI - BRACCO - MINOJA S.R.L.

GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)

Effective date: 19980522

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980625

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980625

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 19980625

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LU

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980704

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: 79521

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980731

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19980731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19981023

REG Reference to a national code

Ref country code: IE

Ref legal event code: FD4D

Ref document number: 79521

Country of ref document: IE

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 19990131

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

26N No opposition filed
REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: NL

Payment date: 20020618

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20020628

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20020730

Year of fee payment: 9

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: BE

Payment date: 20020805

Year of fee payment: 9

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030704

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030731

BERE Be: lapsed

Owner name: *CENTRE NATIONAL D'ETUDES SPATIALES

Effective date: 20030731

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20040203

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20030704

NLV4 Nl: lapsed or anulled due to non-payment of the annual fee

Effective date: 20040201

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050704

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20130731

Year of fee payment: 20