WO2023088607A1

WO2023088607A1 - Cryogenic pumping system and innovative integration for sub-kelvin cryogenics below 1.5k

Info

Publication number: WO2023088607A1
Application number: PCT/EP2022/077908
Authority: WO
Inventors: Simon CRISPEL; Alain Ravex
Original assignee: L'air Liquide, Societe Anonyme Pour L'etude Et L'exploitation Des Procedes Georges Claude
Priority date: 2021-11-16
Filing date: 2022-10-07
Publication date: 2023-05-25
Also published as: FR3129201B1; FR3129201A1

Abstract

The invention relates to a refrigeration device (1) comprising a first working circuit (10) for the circulation of a first working fluid (11), the first working circuit (10) comprising the following elements connected in series by a first network of pipes (70): - a first compressor (20); - a cooling unit (300); - a third heat exchanger (30); - a first expansion device (40) of the Joule-Thompson type; - a first reservoir (50) configured so as to exchange heat with an object to be cooled; the device (1) also comprising a thermally insulated chamber (5) and the first working circuit (10) comprising a first pumping member (80) connected to the first network of pipes (70).

Description

Cryogenic pumping system and innovative integration for Sub Kelvin cryogenics below 1.5K

The present invention relates to the field of refrigeration at very low temperatures and more particularly to the field of refrigeration devices at temperatures approaching the Kelvin.

BACKGROUND OF THE INVENTION

A refrigeration device is known comprising a working fluid circulation circuit comprising a working fluid compressor, a first heat exchanger comprising a first hot channel in which circulates a first flow of working fluid to be cooled and a first cold channel in which circulates a second flow of working fluid to cool the first flow, a first pressure reducer of the Joule-Thompson type and a first separation tank. The refrigeration device also comprises a first network of ducts connecting the elements to put in fluid communication a first outlet of the compressor from which the first working fluid is discharged with a first inlet of the first hot channel, a second outlet of the first hot channel with a second inlet of the first expander, a third outlet of the first expander with a third inlet of the first reservoir, a fourth outlet of the first reservoir with a fourth inlet of the first cold channel, a fifth outlet of the first cold channel with a fifth inlet of the first compressor through which the first working fluid is sucked. The refrigeration device also includes a second heat exchanger that includes a second hot channel in heat exchange with the first tank. Such a circuit supplies cold temperatures to the second cold channel of the second exchanger. However, the pressure of the working fluid after it has been cooled to very low temperatures (below the Kelvin) is low, of the order of 0.1 mbar. It is thus necessary, in order to be able to have a large cooling capacity, to introduce a large flow of fluid into the first circuit, which, at low pressures, requires a large volumetric pumping capacity and pipes dimensioned accordingly. This generally leads to the installation of a compression device that consumes a lot of energy, resulting in a bulky refrigeration device that is difficult and costly to operate.

OBJECT OF THE INVENTION

The aim of the invention is in particular to increase the cooling capacity of a refrigeration device incorporating a Joule-Thompson type expansion valve.

un premier organe de transfert du fluide de travail ;

une unité de refroidissement comprenant un premier échangeur thermique comportant un premier canal chaud et un premier canal froid reliés au premier circuit de travail, l’unité de refroidissement comportant également un deuxième échangeur thermique comprenant un deuxième canal chaud relié au premier circuit de travail et un deuxième canal froid relié à une première source froide;

un troisième échangeur thermique comprenant un troisième canal chaud et un troisième canal froid;
un premier détendeur de type Joule-Thompson ;
un premier réservoir configuré pour être en échange thermique avec un objet à refroidir .

To this end, provision is made for a refrigeration device comprising a first working circuit for circulating a first working fluid, the first working circuit comprising the following elements connected in series by a first network of pipes:

a first working fluid transfer member;

a cooling unit comprising a first heat exchanger comprising a first hot channel and a first cold channel connected to the first working circuit, the cooling unit also comprising a second heat exchanger comprising a second hot channel connected to the first working circuit and a second cold channel connected to a first cold source;

a third heat exchanger comprising a third hot channel and a third cold channel;
a first Joule-Thompson type regulator;
a first reservoir configured to be in heat exchange with an object to be cooled .

According to the invention, the device also comprises a thermally insulated enclosure inside which there is at least some of the elements, the first transfer member being located outside the enclosure. The first working circuit also comprises a first pumping member located inside the enclosure and connected to the first network of pipes.

A device capable of circulating a larger quantity of working fluid in the second heat exchanger without modifying the first transfer member is thus obtained, thus allowing improved performance for a given device volume and/or miniaturization of the refrigeration device .

une première sortie de l’organe de transfert de laquelle est refoulé le premier fluide de travail avec une première entrée du premier canal chaud ;
une deuxième sortie du premier canal chaud avec une deuxième entrée du deuxième canal chaud;
une troisième sortie du canal chaud à une troisième entrée du troisième canal chaud;
une quatrième sortie du troisième canal chaud (31) avec une quatrième entrée du premier détendeur;
une cinquième sortie du premier détendeur avec une cinquième entrée du premier réservoir ;
une sixième sortie du premier réservoir avec une sixième entrée du troisième canal froid ;
une septième sortie du troisième canal froid avec une huitième entrée du premier organe de transfert par laquelle le premier fluide de travail est aspiré ;

According to a particular embodiment, the first pipe network is arranged to connect:

a first outlet of the transfer member from which the first working fluid is discharged with a first inlet of the first hot runner;
a second hot runner second output with a second hot runner second input;
a third hot runner output to a third hot runner third input;
a fourth output of the third hot runner (31) with a fourth input of the first expander;
a fifth outlet from the first regulator with a fifth inlet from the first tank;
a sixth outlet from the first reservoir with a sixth inlet from the third cold channel;
a seventh outlet of the third cold channel with an eighth inlet of the first transfer member through which the first working fluid is sucked;

the first pumping member being located between the sixth outlet and the eighth inlet.

Advantageously, the first pumping member is directly connected to the eighth inlet.

Advantageously again, the first pumping member is located downstream of the seventh outlet.

The coldest temperature produced by the device is improved when the device comprises a second Joule-Thompson type regulator and a second reservoir, the second regulator comprising a tenth inlet in fluid communication with the first circuit downstream of the third outlet and a tenth outlet in fluid communication with an eleventh inlet of the second reservoir, the second reservoir comprising an eleventh outlet in fluid communication with the eighth inlet, the second reservoir also comprising a first withdrawal of working fluid in liquid phase in fluid communication with the first circuit upstream of the third entry.

The coldest temperature produced by the device is further improved when the device comprises a third Joule-Thompson type expander, a third reservoir and a fifth heat exchanger comprising a fifth hot channel and a fifth cold channel, the third expander comprising a twelfth inlet in fluid communication with the first circuit downstream of the third outlet and a twelfth outlet in fluid communication with a thirteenth inlet of the third tank, the third tank comprising a thirteenth outlet in fluid communication with the eighth inlet, the third separation tank also comprising a second withdrawal of working fluid in the liquid phase in fluid communication with a fourteenth inlet of the fifth hot runner, a fourteenth outlet of the fifth hot runner being in fluid communication with the first circuit upstream of the third inlet, a fifteenth inlet and a fifteenth output of the third cold channel being in fluid communication with the first circuit downstream of the seventh output.

Preferably, the refrigeration device comprises a sixth heat exchanger comprising a sixth hot channel and a sixth cold channel, a fourth Joule-Thompson type expander and a fourth tank, the sixth hot channel comprising a sixteenth inlet in fluid communication with the first work circuit between the first output and the third input and the sixth cold channel includes a sixteenth output in fluid communication with the first work circuit downstream of the fifth output.

Advantageously, the first working fluid comprises a volume proportion of Helium 4 greater than 99.9%.

Advantageously, again, the device comprises a second working circuit for circulating a second working fluid by means of a second transfer member and a second cryogenic pump, the second working circuit comprising at least a first pipe portion in heat exchange with the first tank.

Preferably, the second transfer member is located outside the enclosure. A notable improvement is obtained when the second circuit comprises at least a second pipe portion in heat exchange with the second reservoir and/or when the second working circuit also comprises a fifth Joule Thompson type regulator. The second working fluid may comprise a volume proportion of Helium 3 greater than 99.9%.

The invention also relates to a refrigeration method using a device as described above, the method comprising the following steps:

– compression of the first working fluid;

- cooling of the first working fluid,

- isenthalpic expansion of the first working fluid;

- separation of the first working fluid into a first liquid phase and a second gaseous phase;

– heating of the first fluid;

- Pumping the first fluid.

In addition, the step of isenthalpic expansion of the first working fluid is carried out so as to bring the first working fluid to a temperature between five hundred millikelvins and 4.5 Kelvins before the separation step.

Advantageously, the method comprises the following steps:

– compression of the second working fluid;

- cooling of the second working fluid,

- isenthalpic expansion of the second working fluid;

- separation of the second working fluid into a first liquid phase and a second gaseous phase;

– heating of the second fluid;

- Pumping of the second fluid.

Advantageously again, the step of isenthalpic expansion of the second working fluid is carried out so as to bring the second working fluid to a temperature of between three hundred and seven hundred millikelvin before the separation step.

Other characteristics and advantages of the invention will become apparent on reading the following description of a particular and non-limiting embodiment of the invention.

Reference will be made to the accompanying drawings, among which:

is a schematic representation of a first embodiment of the invention;

is a schematic representation of a second embodiment of the invention;

is a schematic representation of a third embodiment of the invention;

is a schematic representation of a fifth embodiment of the invention;

is a schematic representation of a sixth embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

With reference to the , the refrigeration device according to the invention, and generally designated 1, comprises a first working circuit 10 for circulating a first working fluid 11 - here a fluid comprising a volume proportion of helium 4 isotope equal to 99, 9%. The circuit 10 also comprises the following thermodynamic effectors: a first compressor 20 of the fluid 11, a first cooling unit 300 comprising a first heat exchanger 310- here a counter-current exchanger comprising a first hot channel 311 and a first cold channel 312 The cooling unit 300 also comprises a second heat exchanger 320 comprising a second hot channel 321 and a second cold channel 322. The circuit 10 also comprises a third heat exchanger 30, here a counter-current exchanger comprising a third hot channel 31 and a third cold channel 32, a first pressure reducer 40 of the Joule-Thompson type and a first reservoir 50 for phase separation. The device 1 also comprises a fourth heat exchanger 60 which comprises a fourth hot channel 61 in heat exchange with the first tank 50.

As seen in , the cold channel 322 is connected to an external cold source 330 according to known methods. For example, the external cold source cools a working fluid to the desired temperature and this cooled fluid then flows through channel 322.

une première sortie 21 du compresseur 20, de laquelle est refoulé le fluide 11, avec une première entrée 313 du canal chaud 311 ;
une deuxième sortie 314 du canal chaud 311 avec une deuxième entrée 323 du canal chaud 321 ;
une troisième sortie 324 du canal chaud 321 à une troisième entrée 33 du canal chaud 31 ;
une quatrième sortie 34 du canal chaud 31 avec une quatrième entrée 41 du détendeur 40 ;
une cinquième sortie 42 du détendeur 40 avec une cinquième entrée 51 du réservoir 50 ;
une sixième sortie 52 du réservoir 50 avec une sixième entrée 35 du canal froid 32;
une septième sortie 36 du canal froid 32 avec une septième entrée 315 du canal froid 312 ;
une huitième sortie 316 du canal froid 312 avec une huitième entrée 22 du compresseur 20.

The device 1 also comprises a first network 70 of pipes connecting the thermodynamic effectors to the working circuit 10 to put in fluidic communication:

a first outlet 21 of the compressor 20, from which the fluid 11 is discharged, with a first inlet 313 of the hot channel 311;
a second output 314 of the hot runner 311 with a second input 323 of the hot runner 321;
a third output 324 of the hot runner 321 to a third input 33 of the hot runner 31;
a fourth outlet 34 of the hot channel 31 with a fourth inlet 41 of the expander 40;
a fifth outlet 42 from the regulator 40 with a fifth inlet 51 from the reservoir 50;
a sixth outlet 52 from reservoir 50 with a sixth inlet 35 from cold channel 32;
a seventh output 36 of the cold channel 32 with a seventh input 315 of the cold channel 312;
an eighth output 316 of the cold channel 312 with an eighth input 22 of the compressor 20.

The device 1 also comprises a first cryogenic pump 80 located in the circuit 10 between the sixth output 52 and the eighth input 22. More specifically, the ninth input 81 of the pump 80 is connected to the output 36 and the ninth output 82 of the Pump 80 is connected to the seventh inlet 315. Pump 80 is then downstream from outlet 36 and upstream from inlet 22.

Finally, the device 1 comprises a thermally insulated enclosure 5 and inside which are located the circuit 10 and all the effectors listed above of the device 1 with the exception of the compressor 20.

In operation, the compressor 20 draws in the fluid 11 through the eighth inlet 22 and discharges it through the first outlet 21 after having subjected it to a preferably isothermal compression (the compressed fluid 11 is at the same temperature as the fluid 11 before compression) . For example purposes, illustrative values will be used. The fluid 11 therefore enters through the eighth inlet 22 at a temperature close to ambient temperature (i.e. approximately three hundred Kelvins) and a pressure close to atmospheric pressure (i.e. approximately one bar). The fluid 11 leaves the compressor 20 at a pressure of between ten and twenty-five bars, preferably between fifteen and twenty bars, and a temperature close to ambient temperature (that is to say about three hundred Kelvins). The compressed fluid 11 then enters the cooling unit 300 and comes out at a temperature of about fifteen Kelvins.

The fluid 11 then enters the hot channel 31 in which it is cooled by heat exchange with the flow circulating in the cold channel 32. The fluid 11 then undergoes isenthalpic expansion in the expander 40 before entering the reservoir 50. The tank 50 then comprises two phases at very low temperature of the fluid 11: a first liquid phase 12 and a second gaseous phase 13. The temperature of the fluid 11 present in the tank 50 is between 1.8 and 4.5 Kelvins for a pressure suction of the pump 80 of between fifteen millibars and one bar respectively. Reservoir 50 constitutes the fourth cold channel of fourth exchanger 60 which can be used for direct or indirect cooling, for example, of a quantum computer or superconducting electronic components.

After having yielded cold temperatures to the hot channel 61 of the exchanger 60, the fluid 11 exits from the tank 50 to enter the cold channel 32. On leaving the cold channel 32, the fluid 11 is pumped by the cryogenic pump 80 before be sucked up by the compressor 20. The cryogenic pump 80 then acts on the fluid 11 when the latter has a high volumetric density of Helium isotope 4 (corresponding to the working temperatures and pressures) and thus considerably increases the total flow rate of Helium isotope 4 in the circuit 10 which makes it possible to provide significant cooling power to cool the hot channel 61. The pump 80 is called "cryogenic" because it operates at temperatures below fifty Kelvins.

To this end, the thermally insulated enclosure 5 is configured to contain all the elements of the device at a temperature below ambient temperature when the device is in operation.

Elements similar or analogous to those previously described will bear a numerical reference identical to these in the following description of the second, third, fourth, fifth and sixth embodiments of the invention.

According to a second embodiment shown in , the device 1 comprises, in addition to the elements previously described in relation to the first embodiment, a second regulator 90 of the Joule-Thompson type and a second phase separation reservoir 100 which are both connected to the circuit 10 by the network 70. As illustrated, the two

reservoirs

100, 50 are arranged in series in the circuit. Similarly, the two

regulators

90, 40 are arranged in series in the circuit. The regulator 90 comprises a tenth inlet 91 in fluid communication with the circuit 10 downstream of the first outlet 21 and a tenth outlet 92 in fluid communication with an eleventh inlet 101 of the second reservoir 100. An eleventh outlet 102 of the second reservoir 100 is in fluid communication with the eighth inlet 22. The second reservoir 100 comprises, here, a first withdrawal 103 of fluid 11 in the liquid phase which is in fluid communication with the first circuit 10 upstream of the inlet 33 of the exchanger 30. The regulator 90 and the second tank 100 are both located inside the enclosure 5.

The assembly formed by the second regulator 90 and the second reservoir 100 allows the device 1 to achieve a first drop in temperature of the fluid 11 which will then, after passing through the regulator 40, be at a temperature of the order of 1.8 Kelvins in the first tank 50. That is to say that, compared to the previous embodiment, the example of the provides two

separation tanks

100, 50 in series, the cryogenic pump 80 being configured to maintain a pressure of between 10 mbar and 20 mbar, typically 15 mbar, in the vapor phase of the first tank 50 in order to obtain a temperature of the phase liquid in the first reservoir 50 which is lower than the temperature of the second reservoir 100 and typically this temperature of the liquid phase in the first reservoir 50 is between 1.6 K and 3 K, typically 1.8 K.

According to a third embodiment shown in , the device 1 comprises a third Joule-Thompson type expansion valve 110, a third tank 120 and a fifth heat exchanger 130 (comprising a fifth hot channel 131 and a fifth cold channel 132) which are both connected to the circuit 10 by the network 70. The third regulator 110 comprises a twelfth inlet 111 which is in fluid communication with the circuit 10 downstream of the first outlet 21 and a twelfth outlet 112 which is in fluid communication with a thirteenth inlet 121 of the third tank 120. The third reservoir 120 comprises a thirteenth outlet 122 in fluid communication with the eighth inlet 22. The third reservoir 120 also comprises a second withdrawal 123 of fluid 11 in liquid phase in fluid communication with a fourteenth inlet 133 of the hot channel 131. The fourteenth outlet 134 of the hot runner 131 is in fluid communication with the first circuit 10 upstream of the third inlet 33. More precisely, and in this particular embodiment comprising three expanders in series and three reservoirs in series, the outlet 134 of the hot runner 131 is connected at the inlet 91 of the second regulator 90.

The fifteenth input 135 and the fifteenth output 136 of the cold channel 132 are in fluid communication with the circuit 10 downstream of the output 36.

More precisely, and in this particular embodiment, the inlet 135 of the cold channel 132 is connected to the outlet 82 of the pump 80. The third regulator 110, the third tank 120 and the fifth exchanger 130 are located inside of enclosure 5.

The assembly formed by the third regulator 110 and the third tank 120 allows the device 1 to achieve an additional drop in temperature of the fluid 11 which will then, after passing through the regulator 90, then the second tank 100 and then in the regulator 40 at a temperature of the order of 0.8 to 1 Kelvin in the tank 50.

According to a fourth embodiment shown in broken lines on the , a second cryogenic pump 140, optional, is connected to the circuit 10 between the output 82 and the input 22 (in series with the first pump 80). More precisely, the pump 140 is connected to the outlet 136 of the exchanger 130. That is to say that, compared to the previous embodiments, the example of the provides three separation tanks in series, the cryogenic pump 80 being configured to maintain a pressure of between 0.015 millibar and 0.15 millibar in the vapor phase of the first tank 50 in order to obtain a temperature of the liquid phase lower than the temperature of the

other tanks

120 and 100, this temperature in the first tank 50 being for example between 0.8 Kelvin and 1 Kelvin.

According to a fifth embodiment shown in , the device 1 comprises a sixth heat exchanger 150 comprising a sixth hot channel 151 and a sixth cold channel 152, a fourth expansion valve 160 of the Joule-Thompson type and a fourth reservoir 170.

Hot runner 151 includes a sixteenth inlet 153 in fluid communication with first circuit 10 between outlet 21 and inlet 33. In the particular embodiment shown in , the inlet 153 is connected to the circuit 10 by a connection made between the withdrawal 103 and the inlet 33. The cold channel 152 comprises a sixteenth outlet 156 in fluid communication with the circuit 10 downstream of the outlet 36. The outlet 154 of the hot runner 151 is connected to a seventeenth inlet 161 of the expander 160. The eighteenth outlet 162 of the expander 160 is connected to the eighteenth inlet 171 of the fourth reservoir 170 and the nineteenth outlet 172 of the fourth reservoir 170 is connected to the nineteenth inlet 155 of the cold channel 152. The fourth tank 170 serves as a cold source to cool the hot channel 61.1 of a fourth additional exchanger 60.1. Other exchangers, expanders and additional reservoirs can also be installed in parallel with the exchanger 150, the expander 160, the reservoir 170 and the additional exchanger 60.1 as shown in broken lines on the .

It is thus possible to have a plurality of heat exchangers which distribute the cold power of the device 1 at several distinct points.

That is to say, compared to the previous embodiments, the example of the provides several sets each comprising a heat exchanger 60, 60.1, a

phase separation tank

50, 170, an

expansion valve

40, 160, and a

heat exchanger

30, 150. These sets being supplied in parallel with working fluid by a same outlet 103 of tank 100 and being connected in parallel to the same cryogenic pump 80.

According to a sixth embodiment shown in , the device 1 comprises a second working circuit 180 for circulating a second working fluid 181—here a fluid comprising a volume proportion of helium 3 isotope greater than or equal to 99.9%. The circuit 180 also comprises, in addition to the effectors of the second embodiment, the following thermodynamic effectors: a second compressor 190 of the fluid 181, a fifth expansion valve 200 of the Joule-Thompson type, a fifth tank 210 for phase separation, a third cryogenic pump 220, a seventh heat exchanger 230 and an eighth heat exchanger 240. The second compressor 190 is connected to a second cooling unit 250, identical to the cooling unit 300 and which is connected to the cold source 330.

une vingtième sortie 191 du deuxième compresseur 190 de laquelle est refoulé le fluide 181 avec une vingtième entrée 251 de l’unité de refroidissement 250 ;
une vingt-et-unième sortie 252 de l’unité de refroidissement 250 avec une vingt-et-unième entrée 231 d’un canal chaud 232 de l’échangeur 230;
une vingt-deuxième sortie 233 du canal chaud 232 avec une vingt-deuxième entrée 241 d’un canal chaud 242 de l’échangeur 240;
une vingt-troisième sortie 243 du canal chaud 242 avec une vingt-troisième entrée 201 du cinquième détendeur 200;
une vingt-quatrième sortie 202 du cinquième détendeur 200 avec une vingt-quatrième entrée 211 du cinquième réservoir 210;
une vingt-cinquième sortie 212 du cinquième réservoir 210 avec une vingt-cinquième entrée 244 d’un canal froid 245 de l’échangeur 240 ;
une vingt-sixième sortie 246 du canal froid 245 avec une vingt-septième entrée 221 de la troisième pompe 220;
une vingt-septième sortie 222 de la troisième pompe 220 avec une vingt-septième entrée 234 d’un canal froid 235 de l’échangeur 230 ;
une vingt-huitième sortie 236 du canal froid 235 avec une vingt-huitième entrée 253 de l’unité de refroidissement 250;
une vingt-neuvième sortie 254 de l’unité de refroidissement 250 avec une vingt-neuvième entrée 192 du deuxième compresseur 190.

The device 1 also comprises a second network 260 of pipes connecting the thermodynamic effectors to put in fluidic communication:

a twentieth outlet 191 of the second compressor 190 from which the fluid 181 is discharged with a twentieth inlet 251 of the cooling unit 250;
a twenty-first outlet 252 of the cooling unit 250 with a twenty-first inlet 231 of a hot runner 232 of the exchanger 230;
a twenty-second outlet 233 of the hot runner 232 with a twenty-second inlet 241 of a hot runner 242 of the exchanger 240;
a twenty-third outlet 243 of the hot runner 242 with a twenty-third inlet 201 of the fifth expander 200;
a twenty-fourth outlet 202 of the fifth regulator 200 with a twenty-fourth inlet 211 of the fifth reservoir 210;
a twenty-fifth outlet 212 of the fifth tank 210 with a twenty-fifth inlet 244 of a cold channel 245 of the exchanger 240;
a twenty-sixth outlet 246 of the cold channel 245 with a twenty-seventh inlet 221 of the third pump 220;
a twenty-seventh outlet 222 of the third pump 220 with a twenty-seventh inlet 234 of a cold channel 235 of the exchanger 230;
a twenty-eighth outlet 236 from the cold channel 235 with a twenty-eighth inlet 253 from the cooling unit 250;
a twenty-ninth outlet 254 of the cooling unit 250 with a twenty-ninth inlet 192 of the second compressor 190.

All the effectors of circuit 180 except for the second compressor 190 are located inside enclosure 5.

As seen in , the network 260 comprises a first portion 261 of conduit which extends into the first reservoir 50, a second portion 262 of conduit which extends into the second reservoir 100 and a third portion 263 of conduit which extends into the third reservoir 120. The

portions

261, 262 and 263 can be provided with radial fins in order to improve the heat exchanges respectively with the fluid contained in the first reservoir 50, the second reservoir 100 and the third reservoir 120.

The

portions

261, 262 and 263 are located between the outlet 191 of the second compressor 190 and the inlet 201 of the fifth regulator 200 and contribute to cooling the fluid 181 before its expansion in the fifth regulator 200.

The cooling, using the circuit 10, of the fluid 181 present in the circuit 180 and which itself undergoes an isenthalpic expansion in the fifth regulator 200, makes it possible to further lower the temperature of the cold channel in connection with the hot channel 61 The assembly formed by the fifth regulator 200 and the fifth tank 210 achieves an additional drop in temperature of the fluid 181 which will then, after passing through the fifth regulator 200, be at a temperature of the order of 0.3 Kelvin or lower in the fifth tank 210.

Of course, the invention is not limited to the embodiments described but encompasses any variant falling within the scope of the invention as defined by the claims.

bien qu’ici le premier fluide comprenne une proportion d’isotope 4 d’Hélium supérieure à 99,9 %, l’invention s’applique également à d’autres types de premier fluide comme par exemple un premier fluide comprenant une proportion de l’isotope 3 d’hélium supérieure à 99,9% et avec une température adaptée de pré-refroidissement par la source 330 ;
bien qu’ici les échangeurs soient des échangeurs à tubes à contre-courant, l’invention s’applique également à d’autres types d’échangeurs thermiques, comme par exemple un échangeur à plaques, ou à tubes, les flux chaud et froid pouvant être à contre-courant ou non ;
la pompe cryogénique peut être une pompe de type turbo moléculaire, « Holweck », à roue centrifuge ou toute combinaison de ces technologies;
bien qu’ici la troisième pompe ait été représentée entre deux réservoirs de séparation, l’invention s’applique également à d’autres implantations de la deuxième pompe en aval de la vingtième sortie ;
bien qu’ici on ait décrit un troisième détendeur, un troisième réservoir et un troisième échangeur thermique dans le cadre d’un troisième mode de réalisation qui comprend un deuxième détendeur et un deuxième réservoir, l’invention s’applique également à un troisième détendeur, un troisième réservoir et un troisième échangeur thermique couplés à un circuit dépourvu de deuxième détendeur et de deuxième réservoir ;
le deuxième échangeur thermique peut être du type échangeur à fluide ou à conduction, par exemple un réservoir comprenant au moins une paroi thermiquement conductrice sur laquelle est rapporté un élément à refroidir, ou sur laquelle est fixée une tresse thermiquement conductrice ;
bien qu’ici le dispositif comprenne un deuxième échangeur thermique, l’invention s’applique également à d’autres types d’objets à refroidir, comme par exemple une puce électronique directement en échange thermique avec le premier réservoir par conduction ou bien encore indirectement en échange thermique avec le premier réservoir à l’aide d’un fluide caloporteur ou d’un milieu caloporteur solide pouvant être métallique ;
bien qu’ici l’unité de refroidissement comprenne un unique premier échangeur pour transférer des calories depuis un premier canal chaud vers un premier canal froid qui sont reliés au circuit de travail ainsi qu’un unique deuxième échangeur thermique comprenant un deuxième canal chaud relié au premier circuit de travail et un deuxième canal froid relié à une source froide externe, l’invention s’applique également à une unité de refroidissement comprenant deux ou plus premiers échangeurs pour échanger des calories entre deux portions du premier circuit et/ou deux ou plus deuxièmes échangeurs reliés à une ou plusieurs sources froides externes ;
La source froide 330 peut être comprise en tout ou partie dans l’enceinte 5.
La source froide 330 peut être un réfrigérateur à gaz de cycle, un tube à gaz pulsé, ou toute autre source froide appropriée ;
le canal froid 322 peut être remplacé par un bain de liquide cryogénique, à la température d'évaporation souhaitée, dans lequel baigne le canal chaud 321.
le canal froid 322 peut être remplacé par un lien thermique souple (cuivre ou autre métal conducteur thermique) pour connecter mécaniquement la source froide au canal chaud 321 et le refroidir par conduction.
les compresseurs 20 et 190 peuvent être des organes de transfert quelconque, tel qu’une conduite, une pompe, un échangeur de chaleur, ou une autre machine adaptée ;
bien qu’ici, un compresseur assure la circulation du fluide de travail dans le circuit, l’invention s’applique également à d’autres types d’organes de transfert comme par exemple un simple tuyau ou un échangeur de chaleur. En effet, la pompe cryogénique 80 peut être suffisante pour pomper le fluide dans l’ensemble des conduites du circuit. Cette configuration peut être obtenue après un démarrage du dispositif qui comporte un organe de transfert chaud tel qu’un compresseur. C’est à dire que le dispositif est démarré grâce au compresseur 20 ( ou 190) puis le compresseur est mis hors circuit ou by-passé par un échangeur froid qui peut être configuré pour échanger thermiquement avec une source froide en vue d’un pré-refroidissement ;
bien qu’ici la première et la deuxième unités de refroidissement utilisent une unique source froide , l’invention s’applique également à des unités de refroidissement utilisant des sources froides dédiées ;
bien qu’ici le fluide 11 ressorte de l’unité de refroidissement 300 à une température d’environ 15 K, l’invention s’applique également à une température de sortie du fluide 11 de 10 K, ou comprise entre 5 K et 10 K, notamment entre 6 K et 7 K.

Especially,

although here the first fluid comprises a proportion of Helium 4 isotope greater than 99.9%, the invention also applies to other types of first fluid such as for example a first fluid comprising a proportion of isotope 3 of helium greater than 99.9% and with an adapted temperature of pre-cooling by the source 330;
although here the exchangers are counter-current tube exchangers, the invention also applies to other types of heat exchangers, such as for example a plate or tube exchanger, the hot and cold flows may or may not be countercurrent;
the cryogenic pump can be a pump of the turbomolecular, “Holweck” or centrifugal impeller type or any combination of these technologies;
although here the third pump has been represented between two separation tanks, the invention also applies to other locations of the second pump downstream of the twentieth outlet;
although here a third expansion valve, a third reservoir and a third heat exchanger have been described in the context of a third embodiment which comprises a second expansion valve and a second reservoir, the invention also applies to a third expansion valve , a third reservoir and a third heat exchanger coupled to a circuit devoid of a second expansion valve and a second reservoir;
the second heat exchanger can be of the fluid or conduction exchanger type, for example a tank comprising at least one thermally conductive wall on which is attached an element to be cooled, or on which is fixed a thermally conductive braid;
although here the device comprises a second heat exchanger, the invention also applies to other types of objects to be cooled, such as for example an electronic chip directly in heat exchange with the first reservoir by conduction or even indirectly in heat exchange with the first reservoir using a heat transfer fluid or a solid heat transfer medium which may be metallic;
although here the cooling unit comprises a single first heat exchanger for transferring calories from a first hot channel to a first cold channel which are connected to the working circuit as well as a single second heat exchanger comprising a second hot channel connected to the first working circuit and a second cold channel connected to an external cold source, the invention also applies to a cooling unit comprising two or more first exchangers for exchanging calories between two portions of the first circuit and/or two or more second exchangers connected to one or more external cold sources;
The cold source 330 can be included in whole or in part in the enclosure 5.
The cold source 330 can be a cycle gas refrigerator, a pulsed gas tube, or any other suitable cold source;
the cold channel 322 can be replaced by a bath of cryogenic liquid, at the desired evaporation temperature, in which the hot channel 321 bathes.
the cold channel 322 can be replaced by a flexible thermal link (copper or other thermally conductive metal) to mechanically connect the cold source to the hot channel 321 and cool it by conduction.
the compressors 20 and 190 can be any transfer device, such as a pipe, a pump, a heat exchanger, or another suitable machine;
although here, a compressor ensures the circulation of the working fluid in the circuit, the invention also applies to other types of transfer members such as for example a simple pipe or a heat exchanger. Indeed, the cryogenic pump 80 may be sufficient to pump the fluid in all the conduits of the circuit. This configuration can be obtained after starting the device which comprises a hot transfer member such as a compressor. That is to say that the device is started thanks to the compressor 20 (or 190) then the compressor is switched off or bypassed by a cold exchanger which can be configured to exchange heat with a cold source for a pre - cooling;
although here the first and second cooling units use a single cold source, the invention also applies to cooling units using dedicated cold sources;
although here the fluid 11 leaves the cooling unit 300 at a temperature of approximately 15 K, the invention also applies to an outlet temperature of the fluid 11 of 10 K, or between 5 K and 10 K, especially between 6 K and 7 K.

Claims

Refrigeration device (1) comprising a first working circuit (10) for circulating a first working fluid (11), the first working circuit (10) comprising the following elements connected in series by a first network of pipes (70 ):

a first transfer member (20) of the working fluid (11);

a cooling unit (300) comprising a first heat exchanger (310) comprising a first hot channel (311) and a first cold channel (312) connected to the first working circuit (10), the cooling unit (300) comprising also a second heat exchanger (320) comprising a second hot channel (321) connected to the first working circuit (10) and a second cold channel (322) connected to a first cold source (330);

a third heat exchanger (30) comprising a third hot channel (31) and a third cold channel (32);

a first regulator (40) of the Joule-Thompson type;

a first tank (50) configured to be in heat exchange with an object to be cooled ;

characterized in that the device (1) also comprises an enclosure (5), thermally insulated, inside which is located at least part of the elements, the first transfer member (20) being located outside of the enclosure (5); and in that the first working circuit (10) comprises a first pumping unit (80) located inside the enclosure (5) and connected to the first network of pipes (70).
Device according to claim 1, wherein
the first pipe network (70) is arranged to connect:

a first outlet (21) of the transfer member (20) from which the first working fluid (11) is discharged with a first inlet (313) of the first hot runner (311);

a second output (314) of the first hot runner (311) with a second input (323) of the second hot runner (321);

a third outlet (324) of the hot runner (321) to a third inlet (33) of the third hot runner (31);

a fourth outlet (34) of the third hot runner (31) with a fourth inlet (41) of the first expander (40);

a fifth outlet (42) from the first regulator (40) with a fifth inlet (51) from the first tank (50);

a sixth outlet (52) from the first reservoir (50) with a sixth inlet (35) from the third cold channel (32);

a seventh outlet (36) of the third cold channel (32) with an eighth inlet (22) of the first compressor (20) through which the first working fluid (11) is sucked;

the first pumping member (80) being located between the sixth outlet (52) and the eighth inlet (22).
A refrigeration device (1) according to claim 2, wherein the first pumping member (80) is directly connected to the eighth inlet (22).
A refrigeration device (1) according to claim 2 or 3, wherein the first pumping member (80) is located downstream of the seventh outlet (36).
Refrigeration device (1) according to any one of Claims 2 to 4, comprising a second expansion valve (90) of the Joule-Thompson type and a second reservoir (100), the second expansion valve (90) comprising a tenth inlet (91) in fluid communication with the first circuit (10) downstream of the third outlet (324) and a tenth outlet (92) in fluid communication with an eleventh inlet (101) of the second reservoir (100), the second reservoir (100) comprising an eleventh outlet (102) in fluid communication with the eighth inlet (22), the second reservoir (100) also comprising a first withdrawal (103) of working fluid (11) in liquid phase in fluid communication with the first circuit (10 ) upstream of the third inlet (33).
Refrigeration device according to any one of Claims 2 to 5, comprising a third expansion valve (110) of the Joule-Thompson type, a third tank (120) and a fifth heat exchanger (130) comprising a fifth hot channel (131) and a fifth cold channel (132), the third expander (110) comprising a twelfth inlet (111) in fluid communication with the first circuit (10) downstream of the third outlet (324) and a twelfth outlet (112) in communication with a thirteenth inlet (121) of the third reservoir (120), the third reservoir (120) comprising a thirteenth outlet (122) in fluid communication with the eighth inlet (22), the third reservoir (120) also comprising a second draw-off (123) of working fluid (11) in the liquid phase in fluid communication with a fourteenth inlet (133) of the fifth hot runner (131), a fourteenth outlet (134) of the fifth hot runner (131) being in fluid communication with the first circuit (10) upstream of the third inlet (33), a fifteenth inlet (135) and a fifteenth outlet (136) of the fifth cold channel (132) being in fluid communication with the first circuit (10) downstream of the seventh exit (36).
Refrigeration device (1) according to any one of Claims 2 to 6, comprising a sixth heat exchanger (150) comprising a sixth hot channel (151) and a sixth cold channel (152), a fourth expansion valve (160) of Joule-Thompson type and a fourth reservoir (170), the sixth hot runner (151) comprising a sixteenth inlet (153) in fluid communication with the first working circuit (10) between the first outlet (21) and the third inlet ( 33) and the sixth cold channel (152) includes a sixteenth outlet (156) in fluid communication with the first working circuit (10) downstream of the fifth outlet (42).
Refrigeration device (1) according to any one of the preceding claims, in which the first working fluid (11) comprises a volume proportion of Helium 4 greater than or equal to 99.9%.
Refrigeration device (1) according to any one of the preceding claims, comprising a second working circuit (180) for circulating a second working fluid (181) by means of a second transfer member (190) and a second cryogenic pump (220), the second working circuit (180) comprising at least a first portion ( 261 ) of pipe in heat exchange with the first tank (50).
Refrigeration device (1) according to Claim 9, in which the second transfer member (190) is located outside the enclosure (5).
Refrigeration device (1) according to Claims 9 and 5, in which the second working circuit (180) comprises at least a second portion (2 6 2) of pipe in heat exchange with the second tank (100).
Refrigeration device (1) according to any one of Claims 9 to 11, in which the second working circuit (180) also comprises a fifth expansion valve (200) of the Joule Thompson type.
Refrigeration device (1) according to any one of Claims 9 to 12, in which the second working fluid (181) comprises a volume proportion of Helium 3 greater than or equal to 99.9%.
Refrigeration method using a device according to any one of the preceding claims comprising the following steps:
– compression of the first working fluid;
- cooling of the first working fluid,
- isenthalpic expansion of the first working fluid;
- Separation of the first working fluid into a first liquid phase and a second gaseous phase;
– heating of the first fluid;
- Pumping the first fluid.
A method according to claim 14, wherein the step of isenthalpic expansion of the first working fluid is carried out so as to bring the first working fluid to a temperature between five hundred millikelvins and 4.5 Kelvins before the separation step.
Refrigeration method using a device according to any one of claims 9 to 13 comprising the following steps:
– compression of the second working fluid;
- cooling of the second working fluid,
- isenthalpic expansion of the second working fluid;
- Separation of the second working fluid into a first liquid phase and a second gaseous phase;
– heating of the second fluid;
- Pumping of the second fluid.
A method according to claim 16, wherein the step of isenthalpic expansion of the second working fluid is carried out so as to bring the second working fluid to a temperature between three hundred and seven hundred millikelvin before the separation step.