Cryogenic refrigeration system

Abstract

A cryogenic refrigeration installation comprising a refrigerator (5) containing a cryogenic cycle fluid, an enclosure (2) defining a sealed vacuum volume, at least one thermally conductive tray (3, 4) housed within the enclosure (2), at least one heat exchanger (6) separate from the tray(s) and associated with one of the tray(s) (3, 4), the exchanger (6) having a volume defined by a working surface (61), an attachment surface (62), and a fluid connection surface (63), a cooling circuit (50) ensuring circulation of the cycle fluid within the volume of the exchanger(s) (6) for heat exchange of the cycle fluid with the tray(s) (3, 4) via the exchangers (6), the working surface (61) of the exchangers being configured to accommodate at least part of a device (7) to be thermalized. (Shorthand figure: Fig. 1)

Description

Title of the invention: Cryogenic refrigeration installation

[0001] The present invention relates to a cryogenic refrigeration installation adapted to provide cooling power at temperatures below 100 K and in particular adapted to cool or pre-cool the different levels of a subkelvin refrigerator.

[0002] Subkelvin refrigerators are refrigerators capable of reaching temperatures below 1 K. Examples include dilution refrigerators, Joule-Thomson refrigerators using Helium-4 or Helium-3, and adiabatic demagnetization refrigerators. They allow temperatures to be reached on the order of 10 mK or lower.

[0003] Subkelvin refrigerators, and in particular dilution refrigerators, require cooling capacities of at least 4.2 K to operate. This cooling capacity is usually supplied either from pulsed gas tubes (or "pump tubes"), Gifford MacMahon cryo-refrigerators, or other equivalent devices, or from cryogenic or liquid helium. In the first case, this is referred to as "dry" dilution, while in the second case, it is referred to as "wet" dilution.

[0004] Typically, subkelvin refrigerators comprise a thermally insulated enclosure, such as a cryostat or a cold box, in which the coldest part of the process is housed, and in which one or more trays are cooled to decreasing temperatures. For this purpose, one or more tube feeders or equipment for supplying cryogenic or liquid helium are installed in the enclosure and connected to the trays.

[0005] With the evolution of technology, users of subkelvin refrigerators require more and more cooling power at temperatures below 20 mK, which necessitates also increasing the cooling power supplied up to 4.2 K. The power levels supplied by tube pumps are limited and will soon no longer be suitable for the needs of subkelvin refrigerators, and in particular dilution refrigerators.

[0006] A known solution for increasing the cooling power supplied up to 4.2 K is to increase the number of tube feeders installed in the chamber. However, this approach requires increasing the size of the chamber (to accommodate all the tube feeders), while reducing the experimental area, i.e., the surface area of ​​the trays available to house devices to be cooled, since the combination of tube feeders and trays requires a significant surface area. Furthermore, the tube feeders generate unacceptable mechanical vibrations, which necessitates the installation of a system of decoupling, copper braids for example, which further reduces the available surface area and penalizes thermal performance even more.

[0007] On the other hand, the use of "wet" dilutions requires significant cooling and heating times for the refrigerators, which is no longer suitable for current uses of dilution refrigerators. Furthermore, the transfer of liquid helium to recharge the chamber causes thermal disturbances throughout the chamber, thus reducing the refrigerators' operating time.

[0008] This technology allows for significant cooling capacities combined with large heat exchange surfaces and efficient thermalization. However, the volume of Helium-4 to be stored inside the enclosure can be problematic in terms of handling cryogenic liquid and manufacturing complexity.

[0009] For high-capacity dilution refrigerators, one of the critical requirements is to pre-cool several thousand components. This power can be supplied via heat exchange structures installed at the edge of the trays. The thermalization of the components can also be achieved using heat pipes connected to the tray to be thermalized by copper or graphene braids. In both cases, the thermal connection device (braid, exchange structure, or other) can occupy a significant surface area which consequently remains unused and unusable; that is, the tray surface occupied by the connection device cannot be used to accommodate components to be thermalized.

[0010] In a refrigeration installation including a subkelvin refrigerator, the following problems are not currently solved or not satisfactorily solved.

[0011] Providing cooling power at a plurality of different temperatures in the range between 2 K and 300 K, in particular at temperatures less than or equal to 150 K, less than or equal to 77 K, less than or equal to 50 K, less than or equal to 6 K, less than or equal to 5 K, less than or equal to 3 K or 2.8 K, less than or equal to 2 K or 1.8 K.

[0012] Cool the refrigerator quickly. That is to say, the step of cooling the enclosure, necessary to start the subkelvin refrigeration process, still requires very long times.

[0013] Optimize the experimental surface available in the refrigerator, i.e. increase the surface area of ​​the trays actually usable to accommodate devices to be cooled and reduce the surface area occupied by thermal connection devices.

[0014] To allow the exchange of a quantity of energy much greater than conventional solutions, in particular compared to pulsed gas tubes.

[0015] Replace mechanical cooling systems of the tube pump or Gifford MacMahon type with more efficient, more powerful and less bulky systems.

[0016] Limit the handling of cryogenic liquid and the transfer of cryogenic liquid between the outside and the enclosure, and vice versa.

[0017] The present invention aims to effectively remedy these drawbacks by proposing a cryogenic refrigeration installation comprising a refrigerator including a cryogenic cycle fluid, an enclosure delimiting a sealed vacuum volume, at least one thermally conductive tray sheltered in the enclosure, at least one heat exchanger separate from the tray(s) and associated with one of the trays, the exchanger having a volume delimited by a working surface, an attachment surface and a fluidic connection surface, a cooling circuit ensuring circulation of the cycle fluid inside the volume of the exchanger(s) for heat exchange of the cycle fluid with the trays via the exchangers, the working surface of the exchangers being configured to accommodate at least part of a device to be thermalized.

[0018] The invention thus makes it possible to improve the overall energy efficiency of the system, while simplifying the user experience and increasing the available experimental area.

[0019] According to one embodiment, the cooling circuit includes one or more channels integrated into the volume of the exchangers and configured to distribute the cycle fluid in the volume of the exchangers.

[0020] According to one embodiment, the area of ​​the working surface is greater than the area of ​​the fluidic connection surface, in particular the area of ​​the working surface is at least five times greater than the area of ​​the fluidic connection surface.

[0021] According to one embodiment, the installation includes fastening elements associated with each exchanger and configured to establish and maintain contact between a device to be cooled and the exchanger.

[0022] According to one embodiment, the fastening members comprise one or more attachment structures configured to cooperate with conjugate structures of a device to be cooled, to allow removable attachment of the device to be cooled on the exchanger, the attachment structure being in particular chosen from: a tap, a thread, an orifice, a groove, a stud, a pressure system, a frog clamp.

[0023] According to one embodiment, the fastening members include at least one housing cut into the working surface and configured to accommodate at least part of a device to be cooled.

[0024] According to one embodiment, the working surface comprises a first part equipped with fixing members and a second part without fixing members and configured to be in direct contact with a device to be cooled when the latter is held in contact with the exchanger by the fixing members, the thickness of the wall of the exchanger being greater at the level of the first part than at the level of the second part.

[0025] According to one embodiment, the refrigerator is configured to cool the cycle fluid outside the enclosure and the cooling circuit is configured to bring the cooled cycle fluid inside the enclosure and extract the heated cycle fluid from the enclosure.

[0026] According to one embodiment, the tray(s) are horizontal in the operating configuration and the heat exchangers are fixed on the upper face and / or on the lower face of the trays.

[0027] According to one embodiment, the attachment surface of the exchangers is substantially flat and fixed to the corresponding plate so as to be in direct contact with the surface of the plate.

[0028] According to one embodiment, the working surface of the exchanger comprises one or more planes parallel to the attachment surface and each arranged at a different respective distance from the attachment surface.

[0029] According to one embodiment, the working surface of the exchanger comprises one or more inclined planes relative to the attachment surface.

[0030] According to one embodiment, the cooling circuit comprises pipes including a first portion which extends from the fluidic connection surface of an exchanger in a direction orthogonal or oblique to said surface.

[0031] According to one embodiment, the pipes comprise a second portion parallel to the fluidic connection surface of the exchanger, the first and second pipe portions being connected to each other by an elbow.

[0032] According to one embodiment, the installation includes at least one thermal screen attached to one of the platforms, the thermal screen defining a thermalized volume at a predetermined temperature.

[0033] According to one embodiment, the installation comprises at least two platforms and the cooling circuit includes pipes connecting the heat exchangers together, the pipes being configured to supply the exchangers with cryogenic cycle fluid in series or in parallel.

[0034] According to one embodiment, the cooling circuit includes pipes which pass through at least one of the plates or at least one of the thermal screens, in particular through openings including point contacts.

[0035] According to one embodiment, the installation includes at least one subkelvin refrigerator, in particular a dilution refrigerator, attached to at least one of the trays.

[0036] According to one embodiment, the heat exchangers include fluidic fittings allowing them to be connected to the cooling circuit and have a relatively greater height at the level of these fittings compared to the height of the heat exchangers at the level of the free surface.

[0037] According to one embodiment, a section of the exchanger in a plane parallel to the attachment surface has a rectangular, rhombic, round, elliptical or polygonal shape.

[0038] According to one embodiment, the area of ​​the attachment surface is greater than the area of ​​the fluidic connection surface, in particular the area of ​​the attachment surface is at least five times greater than the area of ​​the fluidic connection surface.

[0039] The invention further relates to a method of cooling a heat-dissipating device to be evacuated, the method using an installation as described in the present application, and comprising a step of fixing at least a part of the power-dissipating device to the working surface of a heat exchanger in order to evacuate the power dissipated by the device via the exchanger.

[0040] The invention may also relate to any alternative device or method comprising any combination of the above or below features, particularly within the scope of the claims.

[0041] The invention will be better understood upon reading the following description and examining the accompanying figures. These figures are given only by way of illustration and in no way limit the invention.

[0042] [Fig. 1] is a schematic and partial representation of an implementation of an installation according to the invention.

[0043] [Fig.2] is a schematic and partial representation of a detail of the embodiment of a installation according to the invention.

[0044] [Fig.3] is a schematic and partial representation of a detail of the embodiment of a installation according to the invention.

[0045] [Fig.4] is a schematic and partial representation of a first mode of construction of a heat exchanger according to the invention.

[0046] [Fig.5] is a schematic and partial representation of a second mode of construction of a heat exchanger according to the invention.

[0047] [Fig.6] is a schematic and partial representation of a third mode of construction of a heat exchanger according to the invention.

[0048] [Fig.7] is a schematic and partial representation of a fourth mode of construction of a heat exchanger according to the invention.

[0049] [Fig.8] is a schematic and partial representation of a fourth mode of construction of a heat exchanger according to the invention.

[0050] [Fig.9] is a schematic and partial representation of a detail of a first mode of the implementation of an installation according to the invention.

[0051] [Fig. 10] is a schematic and partial representation of a detail of a first embodiment of an installation according to the invention.

[0052] [Fig. 11] is a schematic and partial representation of a fifth embodiment of a heat exchanger according to the invention.

[0053] [Fig. 12] is a schematic and partial representation of a detail of a first embodiment of an installation according to the invention.

[0054] [Fig. 13] is a schematic and partial representation of a detail of a first embodiment of an installation according to the invention.

[0055] [Fig. 14] is a schematic and partial representation of a detail of a first embodiment of an installation according to the invention.

[0056] [Fig. 15] is a schematic and partial representation of a detail of a first embodiment of an installation according to the invention.

[0057] [Fig. 16] is a schematic and partial representation of a detail of a first embodiment of an installation according to the invention.

[0058] [Fig. 17] is a schematic and partial representation of a detail of the realization of an installation according to the invention.

[0059] [Fig. 18] is a schematic and partial representation of a detail of the realization of an installation according to the invention.

[0060] [Fig. 19] is a schematic and partial representation of a detail of the realization of an installation according to the invention.

[0061] With reference to [Fig. 1], the cryogenic refrigeration installation 1 according to a first embodiment comprises a refrigerator 5 and an enclosure 2 defining a sealed volume under vacuum and preferably closed by a lid. The refrigerator 5 contains a cryogenic cycle fluid and may be housed, wholly or partially, inside or outside the enclosure. The refrigerator 5 may, in particular, be of the type subjecting a cycle fluid to a sequence of compression, heat exchange, and expansion.

[0062] For example, the refrigerator 5 may include a refrigeration cycle of a cycle fluid. The refrigerator 5 then includes a cycle circuit composed of the following elements arranged in series: a compression mechanism for the cycle fluid, at least one cooling element for the cycle fluid, an expansion mechanism for the cycle fluid and at least one heating element for the expanded cycle fluid.

[0063] The cycle fluid may comprise at least one of the following: helium, hydrogen, nitrogen, neon, argon. The cycle circuit is configured to submit the cycle fluid to a thermodynamic cycle bringing the cycle fluid to at least one end of the cycle circuit at a determined cold temperature.

[0064] The installation 1 includes at least one thermally conductive platform 3, 4 housed in the enclosure 2, and at least one heat exchanger 6 separate from the platform(s) and associated with one of the platforms 3, 4.

[0065] In [Fig.1] an exchanger 6 is associated with each plate 3, 4. At least one of the plates 3, 4 could be associated with at least two exchangers 6.

[0066] The cycle fluid flow is in heat exchange with the trays 3, 4 via the heat exchanger(s) 6 and includes the cycle fluid at the cold temperature. The installation includes a set of pipe(s) 50 supplying at least a portion of the cycle fluid from the cycle circuit to the heat exchanger 6 and returning said fluid from the heat exchanger 6 to the refrigerator cycle circuit 5.

[0067] The cycle circuit can be configured to subject the cycle fluid to a thermodynamic cycle bringing the cycle fluid to several distinct cold temperatures at several ends of the cycle circuit. Several distinct flows of the cycle fluid at said distinct cold temperatures are then put into heat exchange with at least two distinct trays 3, 4 via at least two respective heat exchangers 6.

[0068] The cycle fluid is or preferably contains predominantly helium, the cycle circuit being configured to bring the cycle fluid to at least one cold temperature among: about 80 K, between 20 and 70 K, between 1.5 K and 5 K, and / or into a supercritical and / or two-phase state.

[0069] The refrigerator 5 may include a reservoir of liquefied cryogenic gas, for example liquid nitrogen and / or liquid helium and / or liquid hydrogen and / or liquid neon and / or a mixture of the preceding. This reservoir of liquefied cryogenic gas is preferably located outside the enclosure 2. The installation 1 then includes a set of supply lines for the liquefied cryogenic gas from the reservoir to the heat exchanger(s) 6.

[0070] As illustrated in [Fig. 2] and [Fig. 3], the heat exchanger 6 has a volume delimited by a working surface 61, an attachment surface 62, and a fluidic connection surface 63. The working surface 61 is understood to be all the surfaces exposed to the atmosphere of the enclosure and available to the user of the installation for cooling devices to be thermalized. The attachment surface 62 is all the surfaces of the heat exchanger in contact with the trays 3, 4 and used in particular to mechanically attach the heat exchanger to the tray. The fluidic connection surface 63 is all the surfaces where there is an interface with the cooling circuit as defined below. The attachment surface 62 and the fluidic connection surface 63 do not are not available for, nor usable by the user of the installation to cool devices to be thermalized.

[0071] The heat exchanger 6 is detachable, meaning that it can be attached to or installed on a platform 3, 4 and then detached or removed from the platform 3, 4. The heat exchanger 6 allows for greater flexibility in the design of the installation, in the selection of the positions where the cooling power is supplied or the areas to be cooled. The dimensions and shape of the heat exchanger 6 can therefore be chosen more freely during the design phase of the installation.

[0072] The installation 1 includes a cooling circuit 50 ensuring circulation of the cycle fluid within the volume of the exchanger(s) 6 for heat exchange of the cycle fluid with the trays 3, 4 via the exchangers 6.

[0073] The working surface 61 of the heat exchangers 6 is configured to accommodate at least part of a device 7 to be thermalized (i.e., cooled to a predetermined temperature). This may include a heat-dissipating device to be dissipated. For example, the device 7 may be an electronic device such as an amplifier, an attenuator, a sensor, or any other electronic or microelectronic circuit, or even part of an electrical cable.

[0074] This allows for a reduction in the size of the trays and optimizes the use of the installation's volume and footprint. With a constant tray size, this increases the work surface available to the user.

[0075] This solution also offers the flexibility to be able to evolve the installation over time and / or to adapt and improve existing installations.

[0076] The exchanger 6 can also be used to cool a device in which a fluid to be cooled circulates, in particular Helium-3, Helium-4 or a mixture of the two.

[0077] It is understood that the exchanger 6 thermalizes, via the attachment surface 62, the plate 3, 4. The plate(s) 3, 4 are part of the installation 1 and are not considered, within the meaning of the invention, as devices 7 to be thermalized.

[0078] According to one embodiment, the cooling circuit 50 comprises one or more channels or chambers 56 integrated into the volume of the exchangers 6 and configured to distribute the cycle fluid into the volume of the exchangers 6. Examples are illustrated in [Fig.4], [Fig.5], [Fig.6], [Fig.7], [Fig.8] and [Fig.11].

[0079] According to one embodiment, the area of ​​the working surface 61 is greater than the area of ​​the fluidic connection surface 63. In particular, the area of ​​the working surface 61 is at least five times greater than the area of ​​the fluidic connection surface 63, preferably at least ten times, even more preferably at least twenty times.

[0080] According to one embodiment, the area of ​​the attachment surface 62 is greater than the area of ​​the fluidic connection surface 63, in particular the area of ​​the attachment surface 62 is at least five times greater than the area of ​​the fluidic connection surface 63, preferably at least ten times, even more preferably at least twenty times.

[0081] Thus, installation 1 makes available as much space as possible for the user's needs.

[0082] According to one embodiment, the installation 1 includes fastening elements 70 associated, for example mechanically (fastener or otherwise), with each heat exchanger 6 and configured to establish and maintain contact between a device 7 to be cooled and the heat exchanger 6. The fastening elements 70 may be located on and / or may be included in the heat exchanger 6; they may also be separate from it, for example a clamp or a vise-like structure.

[0083] This establishes thermal contact between the device to be cooled and the heat exchanger. Preferably, the mounting is removable, allowing the device to be changed and / or removed, for example, for replacement or maintenance.

[0084] According to one embodiment, the fastening members 70 comprise one or more fastening structures configured to cooperate with conjugate structures of a device 7 to be cooled, to allow removable fastening of the device 7 to be cooled on the exchanger 6. The fastening structure can for example be chosen from: a tapping, a thread, an orifice, a groove, a stud, a pressure system, a frog clamp.

[0085] When the attachment structure is a thread or tapped hole, several of these may be present. They may be arranged in a uniform grid or sieve over all or part of the working surface, for example as shown in [Fig. 4] and [Fig. 5]. For example, one or more screws or threaded rods 70, or equivalent solutions, may then be used to attach the device 7.

[0086] A clamp-like hanging structure can be made using two plates held together by one or more rods.

[0087] Any other means of exerting pressure orthogonal to the working surface can be used as a clamping structure. Figure 6 gives an example of such a structure.

[0088] According to one embodiment, the fastening members 70 include at least one housing 64 cut into the working surface 61 and configured to accommodate at least part of a device 7 to be cooled.

[0089] This makes it easier to install the device to be cooled, for example by forcing the device in or by pushing it into the housing.

[0090] According to one embodiment, the work surface 61 comprises a first part 611 equipped with fastening members and a second part 612 without fastening members. The second part 612 is configured to be in direct contact with a device 7 to be cooled when the latter is held in contact with the heat exchanger by the fastening members.

[0091] The thickness of the exchanger wall can be greater at the first part 611 than at the second part 612 of the working surface 61.

[0092] This improves heat exchange through the thinner wall of part 612, while ensuring effective attachment to a thicker wall of part 611.

[0093] According to one embodiment, the refrigerator 5 is configured to cool the cycle fluid outside the enclosure 2 and the cooling circuit 50 is configured to bring the cooled cycle fluid inside the enclosure 2 and extract the heated cycle fluid from the enclosure 2 after circulating through the exchanger 6.

[0094] This allows the production of cold to be separated from its use, and optimizes the use of the internal volume of the enclosure. This also makes it possible to reduce or eliminate vibrations generated by the refrigerator that can be transmitted via the heat exchanger 6 to the tray(s) 3, 4.

[0095] The installation is thus configured to reduce or eliminate the transmission within the enclosure of vibrations generated by the refrigerator.

[0096] According to one embodiment, the tray(s) 3, 4 are horizontal in the operating configuration and the heat exchangers 6 are fixed on an upper face 31 and / or on an lower face 32 of the trays.

[0097] This maximizes the usable surface area for the user of the installation.

[0098] According to one embodiment, as illustrated for example in [Fig.3], at least one of the platforms 3, 4 may include a housing 33 intended to accommodate a heat exchanger 6, so that the working surface 61 of the exchanger 6 is at the same level as the surface 31, 32 of the platform.

[0099] As illustrated in [Fig.3], [Fig.9], [Fig.10], [Fig.12], [Fig.13], [Fig.14], [Fig.15] and [Fig.16], threads or tapped holes 70 can also be provided on the upper surface 31 or lower surface 32 of the plates 3, 4.

[0100] This allows, where appropriate, a thermalizing device 7 to be fixed “straddling” between the exchanger 6 and the platform 3, 4. That is to say, the thermalizing device 7 can be installed so that one part is in direct contact with the exchanger 6 while another part is in direct contact with the platform 3, 4.

[0101] It should be noted that, in other configurations, the device 7 to be thermalized can be installed so that one part is in direct contact with the exchanger 6 while another part is in direct contact with the plate 3, 4, by providing attachment structures 70 only at the level of the interchange 6 or only at the level of the platform 3, 4.

[0102] According to one embodiment, the attachment surface 62 of the exchangers 6 is substantially flat and fixed to the corresponding plate 3, 4 so as to be in direct contact with the surface of the plate 3, 4.

[0103] This creates an efficient thermal contact, allowing the cold power to be transferred to the plate.

[0104] In one embodiment, the working surface 61 of the exchanger 6 comprises one or more planes 613, 614 parallel to the attachment surface 62 and each arranged at a different respective distance from the attachment surface 62.

[0105] This allows for the accommodation of thermalizing devices 7 which have parts to be positioned at different levels.

[0106] In one embodiment, the working surface 61 of the exchanger 6 comprises one or more planes 615 inclined with respect to the attachment surface 62.

[0107] This allows for the accommodation of thermalizing devices 7 which need to be operated on one or more slopes.

[0108] According to one embodiment, the cooling circuit 50 comprises pipes 53 including a first portion extending from the fluidic connection surface 63 of an exchanger 6 in a direction orthogonal or oblique to said fluidic connection surface 63.

[0109] The conduits 53 may include a second portion parallel to the fluidic connection surface 63 of the exchanger 6, the first and second portion of the conduit being connected to each other by an elbow.

[0110] This ensures a controlled distance between the pipe 53 and the working surface 61 of the exchanger 6 and allows the surface available to the user of the installation to be increased to accommodate devices 7 to be cooled.

[0111] It is understood that different orientations of the pipe 53 could also make it possible to achieve the effect of moving the pipe 53 away from the surface of the exchanger 6 and thus increase the working area available to the user.

[0112] According to one embodiment, the installation includes at least one thermal screen 9 attached to one of the plates 3, 4, the thermal screen 9 defining a thermalized volume at a predetermined temperature.

[0113] According to one embodiment, the installation comprises at least two trays 3, 4 and the cooling circuit 50 comprises pipes 51 connecting the heat exchangers to each other. The pipes 51 can be configured to supply the exchangers 6 with cryogenic cycle fluid in series or in parallel. The exchangers can be located on the same tray 3, 4 or on different trays 3, 4.

[0114] According to one embodiment, the cooling circuit 50 comprises conduits 51, 52 which pass through at least one of the trays 3, 4 or at least one of the heat shields 9. The conduits 51, 52 may pass through the trays 3, 4 and / or the shields 9 through openings 8 comprising point contacts 80. This limits heat losses by conduction.

[0115] According to one embodiment, the installation includes at least one subkelvin refrigerator 10 attached to at least one of the trays 3, 4. The subkelvin refrigerator may be a dilution refrigerator, a Joule-Thomson refrigerator with Helium-3 or Helium-4, an adiabatic demagnetization refrigerator, or any other device capable of producing cold at a temperature below 1 K, preferably below 100 mK.

[0116] In the case of a dilution refrigerator, it can in particular be configured to produce cooling power at temperatures below 20 mK, preferably below 10 mK.

[0117] According to one embodiment, the heat exchangers 6 include fluid connections allowing them to be connected to the cooling circuit 50. The fluid connections are located at the level of the fluid connection surface 63.

[0118] The heat exchangers 6 may have a relatively greater height at the fluidic connections compared to the height of the heat exchangers at the working surface. That is to say, the total height of the heat exchanger measured on a line orthogonal to the fluidic connection surface 63 is greater than the total height of the heat exchanger measured on a line orthogonal to an adjacent working surface 61.

[0119] This allows for better distribution of the cycle fluid and better homogenization of its flow rate.

[0120] According to one embodiment, a section of the exchanger 6 in a plane parallel to the attachment surface 63 may have a rectangular, rhombic, round, elliptical or polygonal shape.

[0121] The invention also relates to a method for cooling a device 7 to be thermalized. The method uses an installation according to one or more of the embodiments described above and includes a step of fixing at least a part of the device 7 to be thermalized to the working surface 61 of a heat exchanger 6.

[0122] According to one embodiment, the device 7 to be thermalized is fixed “straddling” between the exchanger 6 and the platform 3, 4. That is to say, the device 7 to be thermalized is installed so that one part is in direct contact with the exchanger 6 while another part is in direct contact with the platform 3, 4.

[0123] The device 7 to be thermalized may in particular be a heat-dissipating device to be dissipated, and the process makes it possible to dissipate the power dissipated by the device 7 via exchanger 6. For example, device 7 can be an electronic device such as an amplifier, an attenuator, a sensor, or any other electronic or microelectronic circuit, or even part of an electrical cable.

Claims

Demands

1. Cryogenic refrigeration installation comprising - a refrigerator (5) comprising a cryogenic cycle fluid, - an enclosure (2) delimiting a sealed vacuum volume, - at least one thermally conductive tray (3, 4) sheltered in the enclosure (2), - at least one heat exchanger (6) separate from the tray(s) and associated with one of the tray(s) (3, 4), the exchanger (6) having a volume delimited by a working surface (61), an attachment surface (62) and a fluidic connection surface (63), - a cooling circuit (50) ensuring circulation of the cycle fluid within the volume of the exchanger(s) (6) for heat exchange of the cycle fluid with the tray(s) (3, 4) via the exchangers (6), the working surface (61) of the exchangers being configured to accommodate at least part of a device (7) to be thermalized.

2. Installation according to claim 1, characterized in that the cooling circuit (50) comprises one or more channels (56) integrated into the volume of the exchangers (6) and configured to distribute the cycle fluid in the volume of the exchangers (6).

3. Installation according to any one of claims 1 or 2, characterized in that the area of ​​the working surface (61) is greater than the area of ​​the fluidic connection surface (63), in particular the area of ​​the working surface (61) is at least five times greater than the area of ​​the fluidic connection surface (63).

4. Installation according to any one of claims 1 to 3, characterized in that it comprises fastening members (70) associated with each heat exchanger (6) and configured to establish and maintain contact between a device (7) to be cooled and the heat exchanger (6).

5. Installation according to claim 4, characterized in that the fastening members comprise one or more (70) attachment structures configured to cooperate with structures combined with a device (7) to be cooled, to allow removable fixing of the device (7) to be cooled on the exchanger (6), the attachment structure (70) being chosen in particular from: a tapping, a thread, an orifice, a groove, a stud, a pressure system, a frog clamp.

6. Installation according to claim 4, characterized in that the fixing members comprise at least one housing (64) cut into the working surface (61) and configured to accommodate at least a part of a device (7) to be cooled.

7. Installation according to any one of claims 4 to 6, characterized in that the working surface (61) comprises a first part (611) having fastening members and a second part (612) without fastening members and configured to be in direct contact with a device (7) to be cooled when the latter is held in contact with the exchanger by the fastening members, the thickness of the wall of the exchanger being greater at the level of the first part than at the level of the second part.

8. Installation according to any one of claims 1 to 7, characterized in that the refrigerator (5) is configured to cool the cycle fluid outside the enclosure (2) and the cooling circuit (50) is configured to bring the cooled cycle fluid inside the enclosure (2) and extract the heated cycle fluid from the enclosure (2).

9. Installation according to any one of claims 1 to 8, characterized in that the tray(s) (3, 4) are horizontal in operating configuration and the heat exchangers (6) are fixed to the upper face (31) and / or the lower face (32) of the trays.

10. Installation according to any one of claims 1 to 9, characterized in that the attachment surface (62) of the exchangers (6) is substantially flat and fixed to the corresponding plate (3, 4) so ​​as to be in direct contact with the surface of the plate (3,4).

11. Installation according to claim 10, characterized in that the working surface (61) of the exchanger (6) comprises one or more planes (613, 614) parallel to the attachment surface (62) and each arranged at a different respective distance from the attachment surface (62).

12. Installation according to claim 10, characterized in that the working surface (61) of the exchanger (6) comprises one or more planes (615) inclined with respect to the attachment surface (62).

13. Installation according to any one of claims 1 to 12, characterized in that the cooling circuit (50) comprises pipes (53) including a first portion extending from the fluidic connection surface (63) of an exchanger (6) in a direction orthogonal or oblique to said surface (63).

14. Installation according to claim 13, characterized in that the pipes (53) comprise a second portion parallel to the fluidic connection surface (63) of the exchanger (6), the first and second pipe portions being connected to each other by an elbow.

15. Installation according to any one of claims 1 to 14, characterized in that it comprises at least one thermal screen (9) attached to one of the trays, the thermal screen (9) defining a thermalized volume at a predetermined temperature.

16. Installation according to any one of claims 1 to 15, characterized in that it comprises at least two trays (3, 4) and in that the cooling circuit (50) comprises pipes (51) connecting the heat exchangers together, the pipes (51) being configured to supply the exchangers (6) with cryogenic cycle fluid in series or in parallel.

17. Installation according to any one of claims 15 or 16, characterized in that the cooling circuit (50) comprises conduits (51, 52) which pass through at least one of the trays (3, 4) or at least one of the heat shields (9), in particular through openings (8) comprising point contacts (80).

18. Installation according to any one of claims 1 to 16, characterized in that it comprises at least one subkelvin refrigerator (10), in particular a dilution refrigerator, attached to at least one of the trays.

19. A method for cooling a heat-dissipating device (7) to be evacuated, the method using an installation according to any one of claims 1 to 18, and comprising a step of fixing at least a part of the power-dissipating device (7) to the working surface (61) of a heat exchanger (6) in order to evacuate the power dissipated by the device (7) via the exchanger (6).