WO2022124162A1 - Cryogenic refrigerator and heat flow meter - Google Patents

Cryogenic refrigerator and heat flow meter Download PDF

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Publication number
WO2022124162A1
WO2022124162A1 PCT/JP2021/044121 JP2021044121W WO2022124162A1 WO 2022124162 A1 WO2022124162 A1 WO 2022124162A1 JP 2021044121 W JP2021044121 W JP 2021044121W WO 2022124162 A1 WO2022124162 A1 WO 2022124162A1
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WO
WIPO (PCT)
Prior art keywords
heat transfer
transfer member
low temperature
temperature side
side heat
Prior art date
Application number
PCT/JP2021/044121
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French (fr)
Japanese (ja)
Inventor
健太 出村
Original Assignee
住友重機械工業株式会社
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Publication date
Application filed by 住友重機械工業株式会社 filed Critical 住友重機械工業株式会社
Priority to CN202180079250.7A priority Critical patent/CN116584180A/en
Publication of WO2022124162A1 publication Critical patent/WO2022124162A1/en

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    • 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
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N60/00—Superconducting devices
    • H10N60/80—Constructional details
    • H10N60/81—Containers; Mountings

Definitions

  • the present invention relates to an ultra-low temperature refrigerator incorporating a heat flow meter and an ultra-low temperature device including the ultra-low temperature refrigerator.
  • the present invention also relates to a heat flow meter installed in a heat transfer path from the ultra-low temperature refrigerator to the object to be cooled, and an ultra-low temperature device including the heat flow meter.
  • Cryogenic refrigerators are used to cool a variety of objects to be cooled, such as superconducting equipment such as superconducting coils, other equipment operating in cryogenic environments, and cryogenic refrigerants that cool these equipment.
  • the ultra-low temperature refrigerator has a cooling stage that is thermally coupled to the object to be cooled and cools it, and the cooling stage is installed in the cryostat so that it is placed together with the object to be cooled in an adiabatic vacuum vessel also called a cryostat. Can be used. If the temperature of the cryogenic refrigerator or the object to be cooled is monitored during operation and the temperature rises above the standard, it is considered that something has gone wrong.
  • Aged deterioration can be considered as one of the causes of cooling failure in ultra-low temperature equipment.
  • the refrigerating capacity of the cryogenic refrigerator gradually decreases, the cryostat gradually deteriorates, and the heat insulation performance becomes insufficient, so that the cooling temperature gradually decreases. It tends to increase.
  • Anomaly detection based on temperature rise merely indicates that an abnormality has occurred somewhere in the cryogenic device, and does not identify the cause. For example, it is not possible to immediately know whether the abnormality occurred in the ultra-low temperature freezer or the cryostat. Further studies will be required to take measures to eliminate the abnormality, and recovery will take time.
  • One of the exemplary objects of an aspect of the present invention is to effectively deal with poor cooling of cryogenic devices or its signs.
  • the ultra-low temperature refrigerator connects the low temperature side heat transfer member and the high temperature side heat transfer member, the low temperature side heat transfer member and the high temperature side heat transfer member, and the low temperature side heat transfer member.
  • a cooling stage having a heat resistance member that mediates the thermal contact between the member and the high temperature side heat transfer member, a low temperature side temperature sensor attached to the low temperature side heat transfer member and measuring the temperature of the low temperature side heat transfer member, and a high temperature side. It is equipped with a high temperature side temperature sensor attached to the heat transfer member and measuring the temperature of the high temperature side heat transfer member.
  • the ultra-low temperature refrigerator connects the low temperature side heat transfer member and the high temperature side heat transfer member, the low temperature side heat transfer member and the high temperature side heat transfer member, and the low temperature side heat transfer member.
  • the low-temperature side heat transfer member is provided with a low-temperature side temperature sensor mounting portion
  • the high-temperature side heat transfer member is provided with a cooling stage having a member and a heat resistance member that mediates thermal contact between the high-temperature side heat transfer member.
  • a high temperature side temperature sensor mounting portion is provided.
  • a heat flow meter installed in a heat transfer path from a cryogenic refrigerator to an object to be cooled is provided.
  • the heat transfer meter is provided on the low temperature side heat transfer member provided on the heat transfer path on the extremely low temperature refrigerator side and on the high temperature side provided on the cooled side on the heat transfer path and separated from the low temperature side heat transfer member.
  • a heat transfer member a heat resistance member arranged between the low temperature side heat transfer member and the high temperature side heat transfer member, and mediating the heat contact between the low temperature side heat transfer member and the high temperature side heat transfer member, and a low temperature
  • a low-temperature side temperature sensor attached to the side heat transfer member to measure the temperature of the low-temperature side heat transfer member
  • a high-temperature side temperature sensor attached to the high-temperature side heat transfer member to measure the temperature of the high-temperature side heat transfer member.
  • FIG. 1 is a diagram schematically showing an ultra-low temperature device 10 according to an embodiment.
  • the cryogenic device 10 is configured to cool the superconducting coil 12 as an example of the object to be cooled from room temperature to a cryogenic temperature, and to maintain the superconducting coil 12 at a cryogenic temperature during use of the superconducting coil 12. ..
  • the superconducting coil 12 is highly used as a magnetic field source for, for example, a single crystal pulling device, an NMR system, an MRI system, an accelerator such as a cyclotron, a high energy physical system such as a nuclear fusion system, or other high magnetic field utilization equipment (not shown). It is mounted on a magnetic field utilization device and can generate the high magnetic field required for the device.
  • the superconducting coil 12 is configured to generate a strong magnetic field by energizing the superconducting coil 12 in a state of being cooled to an extremely low temperature equal to or lower than the superconducting transition temperature.
  • the cryogenic device 10 includes a cryogenic refrigerator 20, a vacuum container 30, and a radiant heat shield 40.
  • the cryogenic device 10 is not a dip cooling type in which the superconducting coil 12 is immersed in a cryogenic liquid refrigerant such as liquid helium to cool it, but the superconducting coil 12 is directly cooled by the cryogenic refrigerator 20. It is configured as a conduction cooling type.
  • the cryogenic refrigerator 20 is thermally coupled to the superconducting coil 12 so as to cool the superconducting coil 12 by conduction cooling.
  • one cryogenic refrigerator 20 is shown as an example in FIG. 1, the cryogenic device 10 may be one and the same object to be cooled, if necessary, for example, when the superconducting coil 12 is large. May be provided with a plurality of cryogenic refrigerators 20 for cooling.
  • the ultra-low temperature refrigerator 20 includes a cooling stage 22 for cooling an object by conduction cooling, more specifically, a first cooling stage 22a and a second cooling stage 22b.
  • the ultra-low temperature refrigerator 20 is installed in the vacuum container 30, and the first cooling stage 22a and the second cooling stage 22b are arranged in the vacuum container 30.
  • the first cooling stage 22a and the second cooling stage 22b are formed of, for example, a metal material such as copper or other material having a high thermal conductivity.
  • the cryogenic refrigerator 20 includes a first cylinder 24a, a second cylinder 24b, a drive unit 26, and a mounting flange 28.
  • the first cylinder 24a connects the mounting flange 28 to the first cooling stage 22a
  • the second cylinder 24b connects the first cooling stage 22a to the second cooling stage 22b.
  • the drive unit 26 is attached to the mounting flange 28 on the side opposite to the first cylinder 24a.
  • the first cylinder 24a and the second cylinder 24b are, for example, members having a cylindrical shape, and the second cylinder 24b has a smaller diameter than the first cylinder 24a.
  • the first cylinder 24a and the second cylinder 24b are coaxially arranged, and the lower end of the first cylinder 24a is rigidly connected to the upper end of the second cylinder 24b.
  • the cryogenic refrigerator 20 is a Gifford-McMahon (GM) refrigerator
  • the first cylinder 24a and the second cylinder 24b contain a first displacer and a second displacer having a cold storage material, respectively. ing.
  • the first displacer and the second displacer are connected to each other and can reciprocate along the first cylinder 24a and the second cylinder 24b, respectively.
  • the drive unit 26 includes a motor and a connecting mechanism for connecting the motor to the displacers so as to convert the rotational motion output by the motor into the reciprocating motion of the first displacer and the second displacer. Further, the drive unit 26 includes a pressure switching valve that periodically switches the pressure inside the first cylinder 24a and the second cylinder 24b between high pressure and low pressure, and this pressure switching valve is also driven by the motor.
  • the first cylinder 24a, the first cooling stage 22a, the second cylinder 24b, and the second cooling stage 22b are inserted into the vacuum vessel 30 through the opening of the vacuum vessel 30, and the second cooling stage 22b is inserted into the opening.
  • the mounting flange 28 is mounted and mounted on the vacuum vessel 30.
  • the drive unit 26 is arranged outside the vacuum container 30. In this way, the ultra-low temperature refrigerator 20 can be installed in the vacuum container 30 so that the first cooling stage 22a and the second cooling stage 22b are arranged in the vacuum container 30.
  • the cryogenic refrigerator 20 includes a compressor (not shown) for working gas (for example, helium gas) and an expander also called a cold head, and the refrigerator and the expander constitute a refrigerating cycle of the cryogenic refrigerator 20.
  • the first cooling stage 22a and the second cooling stage 22b are each cooled to a desired cryogenic temperature.
  • the first cooling stage 22a is cooled to a first cooling temperature, for example, 30K to 80K
  • the second cooling stage 22b is cooled to a second cooling temperature, for example, 3K to 20K, which is lower than the first cooling temperature.
  • the second cooling temperature is lower than the superconducting transition temperature of the superconducting coil 12.
  • the cryogenic refrigerator 20 is, for example, a two-stage GM refrigerator, but may be a pulse tube refrigerator, a sterling refrigerator, or another type of cryogenic refrigerator.
  • the cryogenic refrigerator 20 may be a single-stage GM refrigerator or another type of cryogenic refrigerator as long as it can provide a desired cooling temperature.
  • the vacuum container 30 is configured to separate the vacuum region 32 from the external environment 14.
  • the vacuum region 32 is defined in the vacuum container 30.
  • the vacuum vessel 30 may be, for example, a cryostat.
  • the superconducting coil 12, the cooling stage 22 of the cryogenic refrigerator 20, and the radiant heat shield 40 are arranged in the vacuum region 32 and are vacuum-insulated from the external environment 14.
  • the heat insulating material may be provided along the surface of the wall member of the vacuum container 30 that separates the vacuum region 32 from the external environment 14, or inside the wall member.
  • the radiant heat shield 40 is thermally coupled to the first cooling stage 22a and cooled to the first cooling temperature.
  • the radiant heat shield 40 is directly attached to the first cooling stage 22a and is thermally coupled to the first cooling stage 22a.
  • the radiant heat shield 40 may be attached to the first cooling stage 22a via a flexible or rigid heat transfer member.
  • the radiant heat shield 40 is formed of a metal material such as copper or other material having a high thermal conductivity.
  • the radiant heat shield 40 is arranged so as to surround the superconducting coil 12 cooled to the second cooling temperature, the second cooling stage 22b of the ultra-low temperature refrigerator 20, and other low-temperature parts, and these low-temperature parts are arranged from the radiant heat from the outside. Can be thermally protected.
  • the superconducting coil 12 is thermally coupled to the second cooling stage 22b via the heat transfer member 42 and cooled to the second cooling temperature.
  • the heat transfer member 42 may be a flexible or rigid heat transfer member, and is formed of a metal material such as copper or other material having a high thermal conductivity.
  • the superconducting coil 12 may be directly attached to the second cooling stage 22b.
  • a heat flow meter is incorporated in the first cooling stage 22a of the ultra-low temperature refrigerator 20.
  • the first cooling stage 22a connects the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, and the low temperature side heat transfer member 50. It has a heat resistance member 54 that mediates the heat contact of the high temperature side heat transfer member 52.
  • the low temperature side heat transfer member 50 is provided at the low temperature end of the first cylinder 24a.
  • the high temperature side heat transfer member 52 is arranged in a non-contact manner with a gap from the low temperature side heat transfer member 50 and the first cylinder 24a, and is thermally connected to the low temperature side heat transfer member 50 only through the thermal resistance member 54.
  • the high temperature side heat transfer member 52 is thermally coupled to the radiant heat shield 40 which is the object to be cooled of the first cooling stage 22a.
  • the high temperature side heat transfer member 52 may be provided as a flange for fastening the first cooling stage 22a to the radiant heat shield 40.
  • the radiant heat shield 40 is cooled from the low temperature side heat transfer member 50 via the thermal resistance member 54 and the high temperature side heat transfer member 52.
  • FIG. 2 is a partially cutaway perspective view schematically showing the heat flow meter according to the embodiment.
  • the first cooling stage 22a is shown with the second cylinder 24b on the upper side and the first cylinder 24a on the lower side, upside down from the ultra-low temperature refrigerator 20 shown in FIG.
  • the low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the heat resistance member 54 are annular, and the heat resistance member 54 is along the circumferences of the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, respectively. It is joined to the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52.
  • the low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the thermal resistance member 54 are arranged coaxially with the central axis of the ultra-low temperature refrigerator 20 (that is, the central axis of the first cylinder 24a and the second cylinder 24b). There is. In this way, the first cooling stage 22a incorporating the heat flow meter is arranged so as to surround the first cylinder 24a.
  • the low temperature side heat transfer member 50 is a circular short cylinder-shaped block, and its inner peripheral surface is joined to the low temperature end of the first cylinder 24a by brazing.
  • the high temperature side heat transfer member 52 is a ring member having a larger diameter than the low temperature side heat transfer member 50, and has a gap of, for example, several mm in the central axis direction of the cryogenic refrigerator 20 from the low temperature side heat transfer member 50. Is arranged.
  • the high temperature side heat transfer member 52 is arranged on the second cylinder 24b side with respect to the low temperature side heat transfer member 50.
  • the thermal resistance member 54 connects the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 in the axial direction.
  • the thermal resistance member 54 is a circular thin-walled short cylinder (for example, in the shape of a pipe), and its diameter is substantially equal to the inner diameter of the high temperature side heat transfer member 52 and the outer diameter of the low temperature side heat transfer member 50.
  • the thermal resistance member 54 is joined to the low temperature side heat transfer member 50 by brazing at one end in the axial direction over the entire circumference, and is joined to the high temperature side heat transfer member 52 over the entire circumference at the other end in the axial direction.
  • the brazing may be, for example, placing brazing using silver brazing. Alternatively, a joining method other than brazing may be used.
  • the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 generated by the heat resistance member 54 The temperature difference is preferably at least 0.5K, or at least 1K. Further, in order to cool the object to be cooled well, the temperature difference between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 generated by the thermal resistance member 54 shall be at most 5K or at most 3K. Is preferable.
  • the heat resistance member 54 has a higher thermal conductivity than the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 in order to generate a temperature difference between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52.
  • the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 are materials suitable as a cooling stage 22 of the ultra-low temperature refrigerating machine 20, for example, copper (for example, pure copper such as tough pitch copper and oxygen-free copper) as described above. It is made of metal material or other material with high thermal conductivity. Therefore, the heat resistance member 54 may be formed of an iron-based material such as stainless steel, brass or another copper alloy, aluminum, or a metal material having a lower thermal conductivity than copper, such as an aluminum alloy.
  • the heat resistance member 54 is more than this. It may be formed of a copper material having a low thermal conductivity (for example, phosphorus deoxidized copper).
  • the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 are typically formed of the same material, but may be formed of different materials.
  • the ultra-low temperature device 10 includes a low temperature side temperature sensor 56 and a high temperature side temperature sensor 58.
  • the low temperature side temperature sensor 56 is attached to the low temperature side heat transfer member 50 and measures the temperature of the low temperature side heat transfer member 50.
  • the high temperature side temperature sensor 58 is attached to the high temperature side heat transfer member 52 and measures the temperature of the high temperature side heat transfer member 52.
  • the temperature sensor wiring 60 extending from each of the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 is pulled out of the vacuum container 30 through the vacuum feedthrough 62.
  • the vacuum feedthrough 62 is provided, for example, on the mounting flange 28 of the cryogenic refrigerator 20. Alternatively, the vacuum feedthrough 62 may be provided on the wall member of the vacuum container 30.
  • the low temperature side heat transfer member 50 is provided with the low temperature side temperature sensor mounting portion 64
  • the high temperature side heat transfer member 52 is provided with the high temperature side temperature sensor mounting portion 66.
  • These temperature sensor mounting portions are, for example, through holes or non-through holes, and the temperature sensor can be mounted.
  • the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 are inserted and attached to the low temperature side temperature sensor mounting portion 64 and the high temperature side temperature sensor mounting portion 66, respectively (for example, they may be bonded).
  • the ultra-low temperature refrigerator 20 may be provided in a state where the temperature sensor is not attached, and the ultra-low temperature refrigerator 20 is placed in the vacuum container 30 after the temperature sensor is attached to the attachment portion at the assembly stage of the ultra-low temperature device 10. It may be assembled. Alternatively, the temperature sensor may be attached at the manufacturing stage of the ultra-low temperature refrigerator 20, and the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 may be attached in advance to the first cooling stage 22a.
  • the ultra-low temperature device 10 is arranged outside the vacuum container 30 and includes a diagnostic device 100 for diagnosing the ultra-low temperature device 10.
  • the diagnostic device 100 includes a calculation unit 110 and an abnormality detection unit 120.
  • the diagnostic device 100 is connected to the low temperature side temperature sensor 56 so as to receive the first measurement temperature signal indicating the measurement temperature Ta of the low temperature side heat transfer member 50 from the low temperature side temperature sensor 56, and is connected to the high temperature side temperature sensor 58 to the high temperature side. It is connected to the high temperature side temperature sensor 58 so as to receive the second measured temperature signal indicating the measured temperature Tb of the heat transfer member 52.
  • the diagnostic device 100 may be mounted on a compressor that supplies and discharges working gas to the cryogenic refrigerator 20.
  • the internal configuration of the diagnostic apparatus 100 is realized by elements and circuits such as a computer CPU and memory as a hardware configuration, and is realized by a computer program or the like as a software configuration, but in the figure, it is appropriately linked by them. It is drawn as a functional block to be realized. It is understood by those skilled in the art that these functional blocks can be realized in various forms by combining hardware and software.
  • FIG. 3 is a flowchart showing a diagnostic method of the ultra-low temperature device 10 according to the embodiment.
  • the temperature is measured by the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 (S10).
  • the diagnostic device 100 receives the first measured temperature signal from the low temperature side temperature sensor 56, and acquires the measured temperature Ta of the low temperature side heat transfer member 50. Further, the diagnostic apparatus 100 receives the second measured temperature signal from the high temperature side temperature sensor 58 and acquires the measured temperature Tb of the high temperature side heat transfer member 52.
  • the calculation unit 110 calculates the heat flow rate from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50 based on the measured temperature Ta of the low temperature side heat transfer member 50 and the measured temperature Tb of the high temperature side heat transfer member 52. (S12).
  • This heat flow calculation can be performed using a known method. For example, the calculation unit 110 first calculates the measured temperature difference (that is, Tb-Ta) between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, and is based on the obtained measured temperature difference and a known relationship. And calculate the heat flow.
  • This known relationship shows the relationship between the temperature difference between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 and the heat flow rate flowing through the thermal resistance member 54 when this temperature difference occurs, and is acquired in advance. It is stored in the calculation unit 110.
  • the abnormality detection unit 120 compares the heat flow rate calculated by the calculation unit 110 with the heat flow rate threshold value Qth (S14).
  • the heat flow threshold value Qth is set to a value equal to or smaller than the upper limit value Qmax of the heat flow rate at which the operation of the ultra-low temperature device 10 is allowed to continue.
  • the heat flow rate upper limit value Qmax may be a value of the heat flow rate at which the ultra-low temperature device 10 is considered to have failed (insulation performance has been significantly deteriorated). Therefore, when the calculated heat flow rate exceeds the heat flow rate upper limit value Qmax, it is considered that the ultra-low temperature device 10 has failed, and the operation of the ultra-low temperature device 10 may be stopped.
  • the heat flow rate threshold value Qth is set to a value smaller than the heat flow rate upper limit value Qmax, when the calculated heat flow rate exceeds the heat flow rate threshold value Qth and is smaller than the heat flow rate upper limit value Qmax, the ultra-low temperature device 10 It is permissible to continue the operation of.
  • the heat flow threshold value Qth is set in advance and stored in the diagnostic device 100 or the abnormality detection unit 120.
  • the heat flow threshold Qth can be appropriately set based on the empirical knowledge of the designer or experiments and simulations by the designer.
  • the abnormality detection unit 120 determines, for example, whether or not the calculated heat flow rate exceeds the heat flow rate threshold value Qth, and when the calculated heat flow rate exceeds the heat flow rate threshold value Qth (Y in S14), vacuum. Deterioration of the heat insulating performance of the container 30 is detected (S16). In this case, due to the deterioration of the heat insulating performance of the vacuum container 30, heat enters the radiant heat shield 40 from the outside of the vacuum container 30, and as a result, the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50. This is because it is considered that the heat input through the thermal resistance member 54 of the above is increased.
  • the abnormality detection unit 120 compares the measured temperature Ta of the low temperature side heat transfer member 50 with the temperature threshold value Tth (S18). ..
  • the temperature threshold value Tth is set to a value equal to or lower than the upper limit temperature Tmax at which the cooling operation of the ultra-low temperature refrigerator 20 is allowed to continue.
  • the upper limit temperature Tmax may be a temperature value at which the ultra-low temperature refrigerator 20 is considered to have failed (the refrigerating performance is significantly deteriorated). Therefore, when the measured temperature Ta reaches the upper limit temperature Tmax, it is considered that the ultra-low temperature refrigerator 20 has failed, and the operation of the ultra-low temperature refrigerator 20 may be stopped.
  • the temperature threshold value Tth is set to a value smaller than the upper limit temperature Tmax, when the measurement temperature Ta exceeds the temperature threshold value Tth and is lower than the upper limit temperature Tmax, the operation of the ultra-low temperature refrigerator 20 can be continued. Permissible.
  • the temperature threshold value Tth is set in advance and stored in the diagnostic device 100 or the abnormality detection unit 120.
  • the temperature threshold value Tth can be appropriately set based on the empirical knowledge of the designer or experiments and simulations by the designer.
  • the abnormality detection unit 120 determines, for example, whether or not the measured temperature Ta of the low temperature side heat transfer member 50 is higher than the temperature threshold Tth, and when the measured temperature Ta is higher than the temperature threshold Tth (Y in S18). A decrease in the refrigerating capacity of the ultra-low temperature refrigerating machine 20 is detected (S20). In this case, although the calculated heat flow rate (that is, heat input from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50 through the heat resistance member 54) is lower than the heat flow rate threshold Qth, the low temperature side Since the measured temperature Ta of the heat transfer member 50 is higher than the temperature threshold value Tth, it is considered that the refrigerating capacity of the ultra-low temperature refrigerator 20 has decreased.
  • the abnormality detection unit 120 determines that the extremely low temperature device 10 is normal (S22). In this case, since the measured temperature Ta of the low temperature side heat transfer member 50 does not exceed the temperature threshold Tth and the calculated heat flow rate is lower than the heat flow rate threshold Qth, the heat insulating performance of the vacuum vessel 30 is also extremely low temperature refrigeration.
  • the refrigerating capacity of the machine 20 can also be regarded as normal.
  • the abnormality detection unit 120 saves the determination result (and the measurement result of temperature and heat flow rate) and outputs it as necessary.
  • the abnormality detection unit 120 may notify the user that an abnormality has been detected, for example, by lighting a warning light provided in the diagnostic apparatus 100, or by other visual method, or by voice or other notification means.
  • the diagnostic apparatus 100 periodically (for example, once a month) repeatedly executes such a diagnostic process.
  • the ultra-low temperature device 10 operates as follows.
  • the first cooling stage 22a of the ultra-low temperature refrigerator 20 is cooled to the first cooling temperature
  • the second cooling stage 22b is cooled to the second cooling temperature.
  • the radiant heat shield 40 is cooled to the first cooling temperature by the first cooling stage 22a.
  • the cooling temperature of the radiant heat shield 40 is slightly higher (for example, about several K) than that of the first cooling stage 22a due to the heat flow meter incorporated in the first cooling stage 22a, but this is a practical problem. It does not become.
  • the superconducting coil 12 is cooled to the second cooling temperature by the second cooling stage 22b. By energizing the superconducting coil 12 from a power source (not shown), the superconducting coil 12 can generate a strong magnetic field. In this way, the ultra-low temperature device 10 can be operated.
  • the ultra-low temperature device During long-term operation of the ultra-low temperature device, for example, aged deterioration may cause a failure in the ultra-low temperature device.
  • the operation of the ultra-low temperature device has to be stopped until it is restored.
  • the time required for recovery tends to be relatively long.
  • the failure can be predicted and dealt with in advance in a planned manner, the impact can be minimized.
  • the cooling temperature of the ultra-low temperature refrigerator With existing technology, there is an attempt to predict the failure of the ultra-low temperature device by monitoring the cooling temperature of the ultra-low temperature refrigerator. This is based on the fact that the cryogenic device becomes harder to cool with long-term use, and the cooling temperature can gradually increase over the long term.
  • the cooling temperature depends not only on the cumulative operating time but also on the ambient environment of the ultra-low temperature device such as heat input from the outside or the operating conditions of the ultra-low temperature device.
  • the cooling temperature does not always change linearly according to the cumulative operating time, but may fluctuate to some extent.
  • the cooling temperature of the first stage is relatively susceptible to seasonal fluctuations in temperature. It is not always easy to distinguish the temperature rise due to such changes in the surrounding environment from the temperature rise due to aging deterioration. In reality, there are only a limited number of situations where failure prediction based on cooling temperature works well.
  • a heat flow meter is incorporated in the first cooling stage 22a of the ultra-low temperature refrigerator 20.
  • the heat flow rate from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50 can be measured. Since the heat flow rate is based on the temperature difference between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, it is less susceptible to the influence of the surrounding environment than the existing temperature monitoring. Further, based on the measured heat flow rate, it is possible to identify whether the cause of the temperature rise is the vacuum vessel 30 or the ultra-low temperature refrigerator 20. In this way, it is possible to grasp the precursor of the failure of the ultra-low temperature device 10 and issue a warning to the user. You can take necessary measures in advance. Therefore, poor cooling or its signs can be effectively dealt with.
  • the temperature threshold value Tth may depend on the heat flow rate from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50. If the heat input increases, the measured temperature Ta of the low temperature side heat transfer member 50 can also increase. Therefore, the larger the calculated heat flow rate, the more the temperature threshold value Tth may be increased. This will lead to a more accurate diagnosis.
  • FIG. 4 shows an example of the heat flow threshold Qth and the temperature threshold Tth.
  • the vertical axis of FIG. 4 represents the cooling temperature of the ultra-low temperature refrigerator 20, and the horizontal axis represents the heat flow rate to the ultra-low temperature refrigerator 20.
  • the ultra-low temperature refrigerator 20 has a relationship between heat input and cooling temperature, which is also called a capacity curve 80, as a unique performance.
  • the capacity curve 80 shows that the cooling temperature increases as the heat input to the ultra-low temperature refrigerator 20 (for example, the first cooling stage 22a) increases. Therefore, the permissible width 82 may be set above and below the capacity curve, and the upper limit value of the permissible width 82 may be used as the temperature threshold value Tth.
  • each measurement result (combination of the calculated heat flow rate and the measured temperature Ta of the low temperature side heat transfer member 50) is illustrated by an arrow.
  • the combination of the heat flow rate and the measurement temperature Ta deviates upward from the allowable width 82 even though the heat flow rate is lower than the heat flow rate threshold value Qth, the freezing of the ultra-low temperature refrigerator 20 is performed. It can be considered that the ability has decreased.
  • the heat flow rate exceeds the heat flow rate threshold value Qth, it is considered that the heat insulating performance of the vacuum container 30 has deteriorated as described above.
  • FIG. 5 is a partial perspective view schematically showing another example of the heat flow meter according to the embodiment.
  • the low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the thermal resistance member 54 may be C-shaped.
  • the thermal resistance member 54 may be joined to the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 along the circumferences of the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, respectively.
  • the gap 68 between both ends of the C-shape is, for example, about several mm, and may be used for passing the temperature sensor wiring 60.
  • the edges and corners of the low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the thermal resistance member 54 may be rounded.
  • the gap 68 may be provided on the side opposite to the low temperature side temperature sensor mounting portion 64 and the high temperature side temperature sensor mounting portion 66 described with reference to FIG.
  • FIG. 6 is a diagram schematically showing a heat flow meter according to an embodiment.
  • This heat flow meter is installed in the heat transfer path from the ultra-low temperature refrigerator 20 (first cooling stage 22a of the ultra-low temperature refrigerator 20) to the object to be cooled (for example, the radiant heat shield 40).
  • the heat flow meter is detachably attached from the first cooling stage 22a of the cryogenic refrigerator 20.
  • the low temperature side heat transfer member in this example, the first cooling stage 22a is provided on the extremely low temperature refrigerator 20 side on the heat transfer path.
  • the high temperature side heat transfer member in this example, the radiant heat shield 40 is provided on the heat transfer path on the cooled side and is arranged away from the first cooling stage 22a.
  • the thermal resistance member 54 is arranged in a state of being sandwiched between the first cooling stage 22a and the radiant heat shield 40, and mediates the thermal contact between the first cooling stage 22a and the radiant heat shield 40.
  • the first cooling stage 22a and the radiant heat shield 40 may be fastened to each other by a fastening member such as a bolt, whereby the thermal resistance member 54 may be sandwiched between the two.
  • the thermal resistance member 54 may be an annular or C-shaped ring-shaped thin plate (for example, a thickness of 0.3 mm to 1 mm), or may be a shim ring, for example. As shown in FIG. 7, the thermal resistance member 54 may have a ring shape having a relatively thick radial width in order to increase the area of thermal contact, and the through hole 70 for the fastening member. May have.
  • the low temperature side temperature sensor 56 is attached to the first cooling stage 22a and measures the temperature of the first cooling stage 22a.
  • the high temperature side temperature sensor 58 is attached to the radiant heat shield 40 and measures the temperature of the radiant heat shield 40.
  • the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 may be connected to the diagnostic device 100 in the same manner as in the above-described embodiment. Even in this way, the heat flow meter can be configured in the same manner as in the above-described embodiment.
  • the thermal resistance member 54 is sandwiched between another low temperature side heat transfer member connected to the first cooling stage 22a and another high temperature side heat transfer member connected to a object to be cooled such as the radiant heat shield 40.
  • a heat transfer meter may be configured.
  • the heat flow meter is incorporated in the first cooling stage 22a of the two-stage ultra-low temperature refrigerator 20, but instead of or together with this, the heat flow meter is incorporated in the second cooling stage 22b. You may. Alternatively, the heat flow meter according to the embodiment may be incorporated in a cooling stage of a single-stage ultra-low temperature refrigerator.
  • the cryogenic device 10 includes a diagnostic device 100 and is configured to automatically perform temperature measurement, heat flow calculation, and abnormality detection based on the temperature measurement, but in one embodiment.
  • the ultra-low temperature device 10 does not have to include the diagnostic device 100.
  • the heat flow rate may be manually calculated from the temperature measurement results of the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58, and the presence or absence of an abnormality may be manually determined.
  • the present invention can be used in the field of an ultra-low temperature refrigerator incorporating a heat flow meter and an ultra-low temperature device equipped with the refrigerator. Further, the present invention can be used in the field of a heat flow meter installed in a heat transfer path from an ultra-low temperature refrigerator to an object to be cooled, and an ultra-low temperature device including the heat flow meter.

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Abstract

This cryogenic refrigerator (20) comprises: a first cooling stage (22a) that has a low temperature-side heat transfer member (50) and a high temperature-side heat transfer member (52) which are disposed separately from one another and a thermal resistance member (54) which connects the low temperature-side heat transfer member (50) and the high temperature-side heat transfer member (52) and mediates the thermal contact between the low temperature-side heat transfer member (50) and the high temperature-side heat transfer member (52); a low temperature-side temperature sensor (56) that is attached to the low temperature-side heat transfer member (50) and measures the temperature of the low temperature-side heat transfer member (50); and a high temperature-side temperature sensor (58) that is attached to the high temperature-side heat transfer member (52) and measures the temperature of the high temperature-side heat transfer member (52).

Description

極低温冷凍機および熱流計Very low temperature freezer and heat flow meter
　本発明は、熱流計を組み込んだ極低温冷凍機、およびこれを備える極低温装置に関する。また、本発明は、極低温冷凍機から被冷却物への伝熱経路に設置される熱流計、およびこれを備える極低温装置に関する。 The present invention relates to an ultra-low temperature refrigerator incorporating a heat flow meter and an ultra-low temperature device including the ultra-low temperature refrigerator. The present invention also relates to a heat flow meter installed in a heat transfer path from the ultra-low temperature refrigerator to the object to be cooled, and an ultra-low temperature device including the heat flow meter.
　極低温冷凍機は、例えば、超伝導コイルなどの超伝導機器、極低温環境で動作するその他の機器、さらにはこうした機器を冷却する極低温冷媒など、様々な被冷却物を冷却するために利用されている。極低温冷凍機は、被冷却物と熱的に結合されこれを冷却する冷却ステージを有し、クライオスタットとも呼ばれる断熱真空容器の中に冷却ステージが被冷却物とともに配置されるようにしてクライオスタットに設置されて使用されうる。動作中に極低温冷凍機または被冷却物の温度が監視され、その温度が基準を超えて上昇した場合、何らかの異常が起きたものとみなされる。 Cryogenic refrigerators are used to cool a variety of objects to be cooled, such as superconducting equipment such as superconducting coils, other equipment operating in cryogenic environments, and cryogenic refrigerants that cool these equipment. Has been done. The ultra-low temperature refrigerator has a cooling stage that is thermally coupled to the object to be cooled and cools it, and the cooling stage is installed in the cryostat so that it is placed together with the object to be cooled in an adiabatic vacuum vessel also called a cryostat. Can be used. If the temperature of the cryogenic refrigerator or the object to be cooled is monitored during operation and the temperature rises above the standard, it is considered that something has gone wrong.
特開２０１２－２０９３８１号公報Japanese Unexamined Patent Publication No. 2012-209381
　極低温装置における冷却不良の原因の一つとして、経年劣化が考えられる。極低温装置を長期的に運用するなかで、例えば、極低温冷凍機の冷凍能力が徐々に低下したり、クライオスタットが徐々に劣化し断熱性能が不十分となったりすることにより、冷却温度は徐々に高まる傾向となる。温度上昇に基づく異常検出は、極低温装置のどこかに異常が起きたことを示すにすぎず、その原因を特定するものではない。例えば、異常が起きたのが、極低温冷凍機なのか、あるいはクライオスタットなのかを直ちに知ることはできない。異常を解消する対策をとるために更なる検討を要することとなり、復旧に時間がかかってしまう。 Aged deterioration can be considered as one of the causes of cooling failure in ultra-low temperature equipment. During the long-term operation of the cryogenic device, for example, the refrigerating capacity of the cryogenic refrigerator gradually decreases, the cryostat gradually deteriorates, and the heat insulation performance becomes insufficient, so that the cooling temperature gradually decreases. It tends to increase. Anomaly detection based on temperature rise merely indicates that an abnormality has occurred somewhere in the cryogenic device, and does not identify the cause. For example, it is not possible to immediately know whether the abnormality occurred in the ultra-low temperature freezer or the cryostat. Further studies will be required to take measures to eliminate the abnormality, and recovery will take time.
　本発明のある態様の例示的な目的のひとつは、極低温装置の冷却不良またはその兆候に効果的に対処することにある。 One of the exemplary objects of an aspect of the present invention is to effectively deal with poor cooling of cryogenic devices or its signs.
　本発明のある態様によると、極低温冷凍機は、離間配置された低温側伝熱部材および高温側伝熱部材と、低温側伝熱部材と高温側伝熱部材を接続し、低温側伝熱部材と高温側伝熱部材の熱接触を媒介する熱抵抗部材とを有する冷却ステージと、低温側伝熱部材に取り付けられ、低温側伝熱部材の温度を測定する低温側温度センサと、高温側伝熱部材に取り付けられ、高温側伝熱部材の温度を測定する高温側温度センサと、を備える。 According to an aspect of the present invention, the ultra-low temperature refrigerator connects the low temperature side heat transfer member and the high temperature side heat transfer member, the low temperature side heat transfer member and the high temperature side heat transfer member, and the low temperature side heat transfer member. A cooling stage having a heat resistance member that mediates the thermal contact between the member and the high temperature side heat transfer member, a low temperature side temperature sensor attached to the low temperature side heat transfer member and measuring the temperature of the low temperature side heat transfer member, and a high temperature side. It is equipped with a high temperature side temperature sensor attached to the heat transfer member and measuring the temperature of the high temperature side heat transfer member.
　本発明のある態様によると、極低温冷凍機は、離間配置された低温側伝熱部材および高温側伝熱部材と、低温側伝熱部材と高温側伝熱部材を接続し、低温側伝熱部材と高温側伝熱部材の熱接触を媒介する熱抵抗部材とを有する冷却ステージを備え、低温側伝熱部材には、低温側温度センサ取付部が設けられ、高温側伝熱部材には、高温側温度センサ取付部が設けられている。 According to an aspect of the present invention, the ultra-low temperature refrigerator connects the low temperature side heat transfer member and the high temperature side heat transfer member, the low temperature side heat transfer member and the high temperature side heat transfer member, and the low temperature side heat transfer member. The low-temperature side heat transfer member is provided with a low-temperature side temperature sensor mounting portion, and the high-temperature side heat transfer member is provided with a cooling stage having a member and a heat resistance member that mediates thermal contact between the high-temperature side heat transfer member. A high temperature side temperature sensor mounting portion is provided.
　本発明のある態様によると、極低温冷凍機から被冷却物への伝熱経路に設置される熱流計が提供される。熱流計は、伝熱経路上で極低温冷凍機側に設けられる低温側伝熱部材と、伝熱経路上で被冷却側に設けられ、低温側伝熱部材から離間して配置される高温側伝熱部材と、低温側伝熱部材と高温側伝熱部材の間に挟み込まれた状態で配置され、低温側伝熱部材と高温側伝熱部材の熱接触を媒介する熱抵抗部材と、低温側伝熱部材に取り付けられ、低温側伝熱部材の温度を測定する低温側温度センサと、高温側伝熱部材に取り付けられ、高温側伝熱部材の温度を測定する高温側温度センサと、を備える。 According to an aspect of the present invention, a heat flow meter installed in a heat transfer path from a cryogenic refrigerator to an object to be cooled is provided. The heat transfer meter is provided on the low temperature side heat transfer member provided on the heat transfer path on the extremely low temperature refrigerator side and on the high temperature side provided on the cooled side on the heat transfer path and separated from the low temperature side heat transfer member. A heat transfer member, a heat resistance member arranged between the low temperature side heat transfer member and the high temperature side heat transfer member, and mediating the heat contact between the low temperature side heat transfer member and the high temperature side heat transfer member, and a low temperature A low-temperature side temperature sensor attached to the side heat transfer member to measure the temperature of the low-temperature side heat transfer member, and a high-temperature side temperature sensor attached to the high-temperature side heat transfer member to measure the temperature of the high-temperature side heat transfer member. Be prepared.
　本発明によれば、極低温装置の冷却不良またはその兆候に効果的に対処することができる。 According to the present invention, it is possible to effectively deal with the cooling failure of the ultra-low temperature device or its sign.
実施の形態に係る極低温装置を模式的に示す図である。It is a figure which shows typically the ultra-low temperature apparatus which concerns on embodiment. 実施の形態に係る熱流計を模式的に示す一部切り欠き斜視図である。It is a partially cutaway perspective view schematically showing the heat flow meter according to the embodiment. 実施の形態に係る極低温装置の診断方法を示すフローチャートである。It is a flowchart which shows the diagnosis method of the ultra-low temperature apparatus which concerns on embodiment. 熱流量しきい値と温度しきい値の一例を示す。An example of the heat flow threshold and the temperature threshold is shown. 実施の形態に係る熱流計の他の一例を模式的に示す部分斜視図である。It is a partial perspective view schematically showing another example of the heat flow meter which concerns on embodiment. 実施の形態に係る熱流計を模式的に示す図である。It is a figure which shows typically the heat flow meter which concerns on embodiment. 熱抵抗部材の一例を示す。An example of a thermal resistance member is shown.
　以下、図面を参照しながら、本発明を実施するための形態について詳細に説明する。説明および図面において同一または同等の構成要素、部材、処理には同一の符号を付し、重複する説明は適宜省略する。図示される各部の縮尺や形状は、説明を容易にするために便宜的に設定されており、特に言及がない限り限定的に解釈されるものではない。実施の形態は例示であり、本発明の範囲を何ら限定するものではない。実施の形態に記述されるすべての特徴やその組み合わせは、必ずしも発明の本質的なものであるとは限らない。 Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description and drawings, the same or equivalent components, members, and processes are designated by the same reference numerals, and duplicate description will be omitted as appropriate. The scales and shapes of the illustrated parts are set for convenience of explanation and are not limitedly interpreted unless otherwise specified. The embodiments are exemplary and do not limit the scope of the invention in any way. Not all features and combinations thereof described in the embodiments are essential to the invention.
　図１は、実施の形態に係る極低温装置１０を模式的に示す図である。極低温装置１０は、被冷却物の一例としての超伝導コイル１２を室温から極低温に冷却するとともに、超伝導コイル１２の使用中、超伝導コイル１２を極低温に維持するように構成される。 FIG. 1 is a diagram schematically showing an ultra-low temperature device 10 according to an embodiment. The cryogenic device 10 is configured to cool the superconducting coil 12 as an example of the object to be cooled from room temperature to a cryogenic temperature, and to maintain the superconducting coil 12 at a cryogenic temperature during use of the superconducting coil 12. ..
　超伝導コイル１２は、例えば単結晶引き上げ装置、ＮＭＲシステム、ＭＲＩシステム、サイクロトロンなどの加速器、核融合システムなどの高エネルギー物理システム、またはその他の高磁場利用機器（図示せず）の磁場源として高磁場利用機器に搭載され、その機器に必要とされる高磁場を発生させることができる。超伝導コイル１２は、超伝導転移温度以下の極低温に冷却された状態で超伝導コイル１２に通電することにより強力な磁場を発生するように構成される。 The superconducting coil 12 is highly used as a magnetic field source for, for example, a single crystal pulling device, an NMR system, an MRI system, an accelerator such as a cyclotron, a high energy physical system such as a nuclear fusion system, or other high magnetic field utilization equipment (not shown). It is mounted on a magnetic field utilization device and can generate the high magnetic field required for the device. The superconducting coil 12 is configured to generate a strong magnetic field by energizing the superconducting coil 12 in a state of being cooled to an extremely low temperature equal to or lower than the superconducting transition temperature.
　極低温装置１０は、極低温冷凍機２０と、真空容器３０と、輻射熱シールド４０とを備える。この実施の形態では、極低温装置１０は、超伝導コイル１２を液体ヘリウムなどの極低温液体冷媒に浸して冷却する浸漬冷却式ではなく、超伝導コイル１２を極低温冷凍機２０で直接冷却する伝導冷却式として構成される。極低温冷凍機２０は、超伝導コイル１２を伝導冷却により冷却するように超伝導コイル１２と熱的に結合されている。なお、図１では例として、１台の極低温冷凍機２０を示しているが、例えば超伝導コイル１２が大型の場合など、必要に応じて、極低温装置１０は、一つの同じ被冷却物を冷却する複数台の極低温冷凍機２０を備えてもよい。 The cryogenic device 10 includes a cryogenic refrigerator 20, a vacuum container 30, and a radiant heat shield 40. In this embodiment, the cryogenic device 10 is not a dip cooling type in which the superconducting coil 12 is immersed in a cryogenic liquid refrigerant such as liquid helium to cool it, but the superconducting coil 12 is directly cooled by the cryogenic refrigerator 20. It is configured as a conduction cooling type. The cryogenic refrigerator 20 is thermally coupled to the superconducting coil 12 so as to cool the superconducting coil 12 by conduction cooling. Although one cryogenic refrigerator 20 is shown as an example in FIG. 1, the cryogenic device 10 may be one and the same object to be cooled, if necessary, for example, when the superconducting coil 12 is large. May be provided with a plurality of cryogenic refrigerators 20 for cooling.
　極低温冷凍機２０は、物体を伝導冷却により冷却する冷却ステージ２２、より具体的には、第１冷却ステージ２２ａと第２冷却ステージ２２ｂを備える。極低温冷凍機２０は、真空容器３０に設置され、第１冷却ステージ２２ａと第２冷却ステージ２２ｂは、真空容器３０の中に配置される。第１冷却ステージ２２ａおよび第２冷却ステージ２２ｂは、例えば、銅などの金属材料またはその他の高い熱伝導率をもつ材料で形成される。 The ultra-low temperature refrigerator 20 includes a cooling stage 22 for cooling an object by conduction cooling, more specifically, a first cooling stage 22a and a second cooling stage 22b. The ultra-low temperature refrigerator 20 is installed in the vacuum container 30, and the first cooling stage 22a and the second cooling stage 22b are arranged in the vacuum container 30. The first cooling stage 22a and the second cooling stage 22b are formed of, for example, a metal material such as copper or other material having a high thermal conductivity.
　また、極低温冷凍機２０は、第１シリンダ２４ａと、第２シリンダ２４ｂと、駆動部２６と、装着フランジ２８とを備える。第１シリンダ２４ａは、装着フランジ２８を第１冷却ステージ２２ａに接続し、第２シリンダ２４ｂは、第１冷却ステージ２２ａを第２冷却ステージ２２ｂに接続する。駆動部２６は、第１シリンダ２４ａとは反対側で装着フランジ２８に取り付けられている。 Further, the cryogenic refrigerator 20 includes a first cylinder 24a, a second cylinder 24b, a drive unit 26, and a mounting flange 28. The first cylinder 24a connects the mounting flange 28 to the first cooling stage 22a, and the second cylinder 24b connects the first cooling stage 22a to the second cooling stage 22b. The drive unit 26 is attached to the mounting flange 28 on the side opposite to the first cylinder 24a.
　第１シリンダ２４ａと第２シリンダ２４ｂは、一例として、円筒形状を有する部材であり、第２シリンダ２４ｂが第１シリンダ２４ａよりも小径である。第１シリンダ２４ａと第２シリンダ２４ｂは同軸に配置され、第１シリンダ２４ａの下端が第２シリンダ２４ｂの上端に剛に連結されている。極低温冷凍機２０がギフォード・マクマホン（Gifford-McMahon；ＧＭ）冷凍機である場合、第１シリンダ２４ａと第２シリンダ２４ｂにはそれぞれ、蓄冷材を内蔵した第１ディスプレーサと第２ディスプレーサが収容されている。第１ディスプレーサと第２ディスプレーサは互いに連結され、それぞれ第１シリンダ２４ａと第２シリンダ２４ｂに沿って往復動可能である。 The first cylinder 24a and the second cylinder 24b are, for example, members having a cylindrical shape, and the second cylinder 24b has a smaller diameter than the first cylinder 24a. The first cylinder 24a and the second cylinder 24b are coaxially arranged, and the lower end of the first cylinder 24a is rigidly connected to the upper end of the second cylinder 24b. When the cryogenic refrigerator 20 is a Gifford-McMahon (GM) refrigerator, the first cylinder 24a and the second cylinder 24b contain a first displacer and a second displacer having a cold storage material, respectively. ing. The first displacer and the second displacer are connected to each other and can reciprocate along the first cylinder 24a and the second cylinder 24b, respectively.
　駆動部２６は、モータと、モータの出力する回転運動を第１ディスプレーサと第２ディスプレーサの往復動に変換するようにモータをこれらディスプレーサに連結する連結機構とを備える。また、駆動部２６は、第１シリンダ２４ａと第２シリンダ２４ｂの内部の圧力を高圧と低圧に周期的に切り替える圧力切替弁を備え、この圧力切替弁もモータによって駆動される。 The drive unit 26 includes a motor and a connecting mechanism for connecting the motor to the displacers so as to convert the rotational motion output by the motor into the reciprocating motion of the first displacer and the second displacer. Further, the drive unit 26 includes a pressure switching valve that periodically switches the pressure inside the first cylinder 24a and the second cylinder 24b between high pressure and low pressure, and this pressure switching valve is also driven by the motor.
　極低温冷凍機２０は、第１シリンダ２４ａ、第１冷却ステージ２２ａ、第２シリンダ２４ｂ、および第２冷却ステージ２２ｂが、真空容器３０の開口部から真空容器３０内に挿入され、この開口部に装着フランジ２８が装着され、真空容器３０に取り付けられる。駆動部２６は、真空容器３０の外に配置される。このようにして、極低温冷凍機２０は、第１冷却ステージ２２ａと第２冷却ステージ２２ｂが真空容器３０内に配置されるようにして真空容器３０に設置することができる。 In the ultra-low temperature refrigerator 20, the first cylinder 24a, the first cooling stage 22a, the second cylinder 24b, and the second cooling stage 22b are inserted into the vacuum vessel 30 through the opening of the vacuum vessel 30, and the second cooling stage 22b is inserted into the opening. The mounting flange 28 is mounted and mounted on the vacuum vessel 30. The drive unit 26 is arranged outside the vacuum container 30. In this way, the ultra-low temperature refrigerator 20 can be installed in the vacuum container 30 so that the first cooling stage 22a and the second cooling stage 22b are arranged in the vacuum container 30.
　極低温冷凍機２０は、作動ガス（たとえばヘリウムガス）の圧縮機（図示せず）と、コールドヘッドとも呼ばれる膨張機とを備え、圧縮機と膨張機により極低温冷凍機２０の冷凍サイクルが構成され、それにより第１冷却ステージ２２ａおよび第２冷却ステージ２２ｂがそれぞれ所望の極低温に冷却される。第１冷却ステージ２２ａは、第１冷却温度、例えば３０Ｋ～８０Ｋに冷却され、第２冷却ステージ２２ｂは、第１冷却温度よりも低い第２冷却温度、例えば３Ｋ～２０Ｋに冷却される。第２冷却温度は、超伝導コイル１２の超伝導転移温度より低い温度である。 The cryogenic refrigerator 20 includes a compressor (not shown) for working gas (for example, helium gas) and an expander also called a cold head, and the refrigerator and the expander constitute a refrigerating cycle of the cryogenic refrigerator 20. The first cooling stage 22a and the second cooling stage 22b are each cooled to a desired cryogenic temperature. The first cooling stage 22a is cooled to a first cooling temperature, for example, 30K to 80K, and the second cooling stage 22b is cooled to a second cooling temperature, for example, 3K to 20K, which is lower than the first cooling temperature. The second cooling temperature is lower than the superconducting transition temperature of the superconducting coil 12.
　極低温冷凍機２０は、一例として、二段式のＧＭ冷凍機であるが、パルス管冷凍機、スターリング冷凍機、またはそのほかのタイプの極低温冷凍機であってもよい。所望の冷却温度を提供できるのであれば、極低温冷凍機２０は、単段式のＧＭ冷凍機またはそのほかのタイプの極低温冷凍機であってもよい。 The cryogenic refrigerator 20 is, for example, a two-stage GM refrigerator, but may be a pulse tube refrigerator, a sterling refrigerator, or another type of cryogenic refrigerator. The cryogenic refrigerator 20 may be a single-stage GM refrigerator or another type of cryogenic refrigerator as long as it can provide a desired cooling temperature.
　真空容器３０は、真空領域３２を外部環境１４から隔てるように構成される。真空領域３２は、真空容器３０内に定められる。真空容器３０は、例えばクライオスタットであってもよい。超伝導コイル１２、極低温冷凍機２０の冷却ステージ２２、輻射熱シールド４０は、真空領域３２に配置され、外部環境１４から真空断熱される。断熱性能を高めるために、真空領域３２を外部環境１４から隔てる真空容器３０の壁部材の表面に沿って、または壁部材の内部に、断熱材料が設けられていてもよい。 The vacuum container 30 is configured to separate the vacuum region 32 from the external environment 14. The vacuum region 32 is defined in the vacuum container 30. The vacuum vessel 30 may be, for example, a cryostat. The superconducting coil 12, the cooling stage 22 of the cryogenic refrigerator 20, and the radiant heat shield 40 are arranged in the vacuum region 32 and are vacuum-insulated from the external environment 14. In order to enhance the heat insulating performance, the heat insulating material may be provided along the surface of the wall member of the vacuum container 30 that separates the vacuum region 32 from the external environment 14, or inside the wall member.
　輻射熱シールド４０は、第１冷却ステージ２２ａと熱的に結合され第１冷却温度に冷却される。輻射熱シールド４０は、第１冷却ステージ２２ａに直接取り付けられ、第１冷却ステージ２２ａと熱的に結合される。あるいは、輻射熱シールド４０は、可撓性または剛性をもつ伝熱部材を介して第１冷却ステージ２２ａに取り付けられてもよい。輻射熱シールド４０は、例えば銅などの金属材料またはその他の高い熱伝導率をもつ材料で形成される。輻射熱シールド４０は、第２冷却温度に冷却される超伝導コイル１２、極低温冷凍機２０の第２冷却ステージ２２ｂ、およびその他の低温部を囲むように配置され、外部からの輻射熱からこれら低温部を熱的に保護することができる。 The radiant heat shield 40 is thermally coupled to the first cooling stage 22a and cooled to the first cooling temperature. The radiant heat shield 40 is directly attached to the first cooling stage 22a and is thermally coupled to the first cooling stage 22a. Alternatively, the radiant heat shield 40 may be attached to the first cooling stage 22a via a flexible or rigid heat transfer member. The radiant heat shield 40 is formed of a metal material such as copper or other material having a high thermal conductivity. The radiant heat shield 40 is arranged so as to surround the superconducting coil 12 cooled to the second cooling temperature, the second cooling stage 22b of the ultra-low temperature refrigerator 20, and other low-temperature parts, and these low-temperature parts are arranged from the radiant heat from the outside. Can be thermally protected.
　超伝導コイル１２は、伝熱部材４２を介して第２冷却ステージ２２ｂと熱的に結合され第２冷却温度に冷却される。伝熱部材４２は、可撓性または剛性をもつ伝熱部材であってもよく、例えば銅などの金属材料またはその他の高い熱伝導率をもつ材料で形成される。超伝導コイル１２は、第２冷却ステージ２２ｂに直接取り付けられてもよい。 The superconducting coil 12 is thermally coupled to the second cooling stage 22b via the heat transfer member 42 and cooled to the second cooling temperature. The heat transfer member 42 may be a flexible or rigid heat transfer member, and is formed of a metal material such as copper or other material having a high thermal conductivity. The superconducting coil 12 may be directly attached to the second cooling stage 22b.
　この実施の形態では、極低温冷凍機２０の第１冷却ステージ２２ａに熱流計が組み込まれている。第１冷却ステージ２２ａは、離間配置された低温側伝熱部材５０および高温側伝熱部材５２と、低温側伝熱部材５０と高温側伝熱部材５２を接続し、低温側伝熱部材５０と高温側伝熱部材５２の熱接触を媒介する熱抵抗部材５４とを有する。低温側伝熱部材５０は、第１シリンダ２４ａの低温端に設けられている。高温側伝熱部材５２は、低温側伝熱部材５０および第１シリンダ２４ａから隙間をあけてこれらとは非接触に配置され、熱抵抗部材５４のみを介して低温側伝熱部材５０と熱的に結合される。高温側伝熱部材５２が、第１冷却ステージ２２ａの被冷却物である輻射熱シールド４０と熱的に結合される。高温側伝熱部材５２は、第１冷却ステージ２２ａを輻射熱シールド４０と締結するためのフランジとして設けられていてもよい。輻射熱シールド４０は、低温側伝熱部材５０から熱抵抗部材５４および高温側伝熱部材５２を介して冷却される。 In this embodiment, a heat flow meter is incorporated in the first cooling stage 22a of the ultra-low temperature refrigerator 20. The first cooling stage 22a connects the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, and the low temperature side heat transfer member 50. It has a heat resistance member 54 that mediates the heat contact of the high temperature side heat transfer member 52. The low temperature side heat transfer member 50 is provided at the low temperature end of the first cylinder 24a. The high temperature side heat transfer member 52 is arranged in a non-contact manner with a gap from the low temperature side heat transfer member 50 and the first cylinder 24a, and is thermally connected to the low temperature side heat transfer member 50 only through the thermal resistance member 54. Combined with. The high temperature side heat transfer member 52 is thermally coupled to the radiant heat shield 40 which is the object to be cooled of the first cooling stage 22a. The high temperature side heat transfer member 52 may be provided as a flange for fastening the first cooling stage 22a to the radiant heat shield 40. The radiant heat shield 40 is cooled from the low temperature side heat transfer member 50 via the thermal resistance member 54 and the high temperature side heat transfer member 52.
　図２は、実施の形態に係る熱流計を模式的に示す一部切り欠き斜視図である。図２では、説明の便宜上、図１に示す極低温冷凍機２０とは上下逆に、第２シリンダ２４ｂを上側、第１シリンダ２４ａを下側として、第１冷却ステージ２２ａが示されている。 FIG. 2 is a partially cutaway perspective view schematically showing the heat flow meter according to the embodiment. In FIG. 2, for convenience of explanation, the first cooling stage 22a is shown with the second cylinder 24b on the upper side and the first cylinder 24a on the lower side, upside down from the ultra-low temperature refrigerator 20 shown in FIG.
　低温側伝熱部材５０、高温側伝熱部材５２、および熱抵抗部材５４は、環状であり、熱抵抗部材５４は、低温側伝熱部材５０と高温側伝熱部材５２それぞれの周に沿って低温側伝熱部材５０と高温側伝熱部材５２に接合されている。低温側伝熱部材５０、高温側伝熱部材５２、および熱抵抗部材５４は、極低温冷凍機２０の中心軸（すなわち第１シリンダ２４ａおよび第２シリンダ２４ｂの中心軸）と同軸に配置されている。このようにして、熱流計が組み込まれた第１冷却ステージ２２ａが第１シリンダ２４ａを囲むように配置されている。 The low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the heat resistance member 54 are annular, and the heat resistance member 54 is along the circumferences of the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, respectively. It is joined to the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52. The low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the thermal resistance member 54 are arranged coaxially with the central axis of the ultra-low temperature refrigerator 20 (that is, the central axis of the first cylinder 24a and the second cylinder 24b). There is. In this way, the first cooling stage 22a incorporating the heat flow meter is arranged so as to surround the first cylinder 24a.
　より具体的には、低温側伝熱部材５０は、円形短筒状のブロックであり、その内周面がろう付けにより第１シリンダ２４ａの低温端に接合されている。高温側伝熱部材５２は、低温側伝熱部材５０に比べて大径の円環部材であり、低温側伝熱部材５０から極低温冷凍機２０の中心軸方向に例えば数ｍｍの隙間をあけて配置されている。高温側伝熱部材５２は、低温側伝熱部材５０に対して第２シリンダ２４ｂ側に配置されている。熱抵抗部材５４は、低温側伝熱部材５０と高温側伝熱部材５２を軸方向に接続する。熱抵抗部材５４は、円形の薄肉短筒（例えばパイプ状）であり、その径が高温側伝熱部材５２の内径および低温側伝熱部材５０の外径とほぼ等しい。熱抵抗部材５４は、軸方向一端で全周にわたり低温側伝熱部材５０とろう付けにより接合され、軸方向他端で全周にわたり高温側伝熱部材５２とろう付けにより接合されている。ろう付けは、例えば、銀ろうを用いた置きろう付けであってもよい。あるいは、ろう付け以外の接合方法が用いられてもよい。 More specifically, the low temperature side heat transfer member 50 is a circular short cylinder-shaped block, and its inner peripheral surface is joined to the low temperature end of the first cylinder 24a by brazing. The high temperature side heat transfer member 52 is a ring member having a larger diameter than the low temperature side heat transfer member 50, and has a gap of, for example, several mm in the central axis direction of the cryogenic refrigerator 20 from the low temperature side heat transfer member 50. Is arranged. The high temperature side heat transfer member 52 is arranged on the second cylinder 24b side with respect to the low temperature side heat transfer member 50. The thermal resistance member 54 connects the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 in the axial direction. The thermal resistance member 54 is a circular thin-walled short cylinder (for example, in the shape of a pipe), and its diameter is substantially equal to the inner diameter of the high temperature side heat transfer member 52 and the outer diameter of the low temperature side heat transfer member 50. The thermal resistance member 54 is joined to the low temperature side heat transfer member 50 by brazing at one end in the axial direction over the entire circumference, and is joined to the high temperature side heat transfer member 52 over the entire circumference at the other end in the axial direction. The brazing may be, for example, placing brazing using silver brazing. Alternatively, a joining method other than brazing may be used.
　熱流計として高温側伝熱部材５２から低温側伝熱部材５０に入る熱流量を良好に測定するために、熱抵抗部材５４によって生成される低温側伝熱部材５０と高温側伝熱部材５２の温度差は、少なくとも０．５Ｋ、または少なくとも１Ｋであることが好ましい。また、被冷却物を良好に冷却するために、熱抵抗部材５４によって生成される低温側伝熱部材５０と高温側伝熱部材５２の温度差は、多くとも５Ｋ、または多くとも３Ｋであることが好ましい。極低温装置１０の正常な動作中にこのような温度差を実現するように、低温側伝熱部材５０、高温側伝熱部材５２、および熱抵抗部材５４の材料の組み合わせ、及び／または各部材の寸法、形状が定められてもよい。 In order to satisfactorily measure the heat flow rate from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50 as a heat flow meter, the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 generated by the heat resistance member 54 The temperature difference is preferably at least 0.5K, or at least 1K. Further, in order to cool the object to be cooled well, the temperature difference between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 generated by the thermal resistance member 54 shall be at most 5K or at most 3K. Is preferable. A combination of materials of the low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the thermal resistance member 54, and / or each member so as to realize such a temperature difference during the normal operation of the ultra-low temperature device 10. Dimensions and shapes may be determined.
　熱抵抗部材５４は、低温側伝熱部材５０と高温側伝熱部材５２との間に温度差を生成するために、低温側伝熱部材５０と高温側伝熱部材５２に比べて熱伝導率の低い材料で形成される。低温側伝熱部材５０と高温側伝熱部材５２は、極低温冷凍機２０の冷却ステージ２２として適する材料、上述のように、例えば、銅（例えば、タフピッチ銅、無酸素銅などの純銅）などの金属材料またはその他の高い熱伝導率をもつ材料で形成される。よって、熱抵抗部材５４は、例えば、ステンレス鋼などの鉄系材料、真鍮または他の銅合金、アルミニウムまたアルミニウム合金など、銅よりも熱伝導率の低い金属材料で形成されてもよい。あるいは、低温側伝熱部材５０と高温側伝熱部材５２が、タフピッチ銅や無酸素銅のような高純度で高熱伝導率の銅材料で形成される場合、熱抵抗部材５４は、これよりも熱伝導率の低い銅材料（例えばリン脱酸銅）で形成されてもよい。なお、低温側伝熱部材５０と高温側伝熱部材５２は、典型的には同じ材料で形成されるが、異なる材料で形成されてもよい。 The heat resistance member 54 has a higher thermal conductivity than the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 in order to generate a temperature difference between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52. Formed of low material. The low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 are materials suitable as a cooling stage 22 of the ultra-low temperature refrigerating machine 20, for example, copper (for example, pure copper such as tough pitch copper and oxygen-free copper) as described above. It is made of metal material or other material with high thermal conductivity. Therefore, the heat resistance member 54 may be formed of an iron-based material such as stainless steel, brass or another copper alloy, aluminum, or a metal material having a lower thermal conductivity than copper, such as an aluminum alloy. Alternatively, when the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 are formed of a high-purity and high thermal conductivity copper material such as tough pitch copper or oxygen-free copper, the heat resistance member 54 is more than this. It may be formed of a copper material having a low thermal conductivity (for example, phosphorus deoxidized copper). The low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 are typically formed of the same material, but may be formed of different materials.
　図１に示されるように、極低温装置１０は、低温側温度センサ５６と高温側温度センサ５８を備える。低温側温度センサ５６は、低温側伝熱部材５０に取り付けられ、低温側伝熱部材５０の温度を測定する。高温側温度センサ５８は、高温側伝熱部材５２に取り付けられ、高温側伝熱部材５２の温度を測定する。低温側温度センサ５６と高温側温度センサ５８それぞれから延びる温度センサ配線６０は、真空フィードスルー６２を通じて真空容器３０外に引き出される。真空フィードスルー６２は、例えば、極低温冷凍機２０の装着フランジ２８に設けられている。あるいは、真空フィードスルー６２は、真空容器３０の壁部材に設けられてもよい。 As shown in FIG. 1, the ultra-low temperature device 10 includes a low temperature side temperature sensor 56 and a high temperature side temperature sensor 58. The low temperature side temperature sensor 56 is attached to the low temperature side heat transfer member 50 and measures the temperature of the low temperature side heat transfer member 50. The high temperature side temperature sensor 58 is attached to the high temperature side heat transfer member 52 and measures the temperature of the high temperature side heat transfer member 52. The temperature sensor wiring 60 extending from each of the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 is pulled out of the vacuum container 30 through the vacuum feedthrough 62. The vacuum feedthrough 62 is provided, for example, on the mounting flange 28 of the cryogenic refrigerator 20. Alternatively, the vacuum feedthrough 62 may be provided on the wall member of the vacuum container 30.
　また、図２に示されるように、低温側伝熱部材５０には、低温側温度センサ取付部６４が設けられ、高温側伝熱部材５２には、高温側温度センサ取付部６６が設けられている。これら温度センサ取付部は、例えば、貫通穴または非貫通穴であり、温度センサを取付可能である。低温側温度センサ５６と高温側温度センサ５８がそれぞれ、低温側温度センサ取付部６４と高温側温度センサ取付部６６に差し込まれて取り付けられる（例えば、接着されてもよい）。 Further, as shown in FIG. 2, the low temperature side heat transfer member 50 is provided with the low temperature side temperature sensor mounting portion 64, and the high temperature side heat transfer member 52 is provided with the high temperature side temperature sensor mounting portion 66. There is. These temperature sensor mounting portions are, for example, through holes or non-through holes, and the temperature sensor can be mounted. The low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 are inserted and attached to the low temperature side temperature sensor mounting portion 64 and the high temperature side temperature sensor mounting portion 66, respectively (for example, they may be bonded).
　極低温冷凍機２０は、温度センサが取り付けられていない状態で提供されてもよく、極低温装置１０の組立段階において温度センサを取付部に取り付けたうえで極低温冷凍機２０を真空容器３０に組み付けてもよい。あるいは、温度センサの取付は極低温冷凍機２０の製造段階で行われ、第１冷却ステージ２２ａに低温側温度センサ５６と高温側温度センサ５８が予め取り付けられていてもよい。 The ultra-low temperature refrigerator 20 may be provided in a state where the temperature sensor is not attached, and the ultra-low temperature refrigerator 20 is placed in the vacuum container 30 after the temperature sensor is attached to the attachment portion at the assembly stage of the ultra-low temperature device 10. It may be assembled. Alternatively, the temperature sensor may be attached at the manufacturing stage of the ultra-low temperature refrigerator 20, and the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 may be attached in advance to the first cooling stage 22a.
　図１を再び参照すると、極低温装置１０は、真空容器３０の外に配置され、極低温装置１０を診断する診断装置１００を備える。診断装置１００は、演算部１１０と異常検出部１２０を備える。診断装置１００は、低温側温度センサ５６から低温側伝熱部材５０の測定温度Ｔａを示す第１測定温度信号を受信するように低温側温度センサ５６と接続され、高温側温度センサ５８から高温側伝熱部材５２の測定温度Ｔｂを示す第２測定温度信号を受信するように高温側温度センサ５８と接続されている。診断装置１００は、極低温冷凍機２０に作動ガスを給排する圧縮機に搭載されてもよい。 Referring to FIG. 1 again, the ultra-low temperature device 10 is arranged outside the vacuum container 30 and includes a diagnostic device 100 for diagnosing the ultra-low temperature device 10. The diagnostic device 100 includes a calculation unit 110 and an abnormality detection unit 120. The diagnostic device 100 is connected to the low temperature side temperature sensor 56 so as to receive the first measurement temperature signal indicating the measurement temperature Ta of the low temperature side heat transfer member 50 from the low temperature side temperature sensor 56, and is connected to the high temperature side temperature sensor 58 to the high temperature side. It is connected to the high temperature side temperature sensor 58 so as to receive the second measured temperature signal indicating the measured temperature Tb of the heat transfer member 52. The diagnostic device 100 may be mounted on a compressor that supplies and discharges working gas to the cryogenic refrigerator 20.
　診断装置１００の内部構成は、ハードウェア構成としてはコンピュータのＣＰＵやメモリをはじめとする素子や回路で実現され、ソフトウェア構成としてはコンピュータプログラム等によって実現されるが、図では適宜、それらの連携によって実現される機能ブロックとして描いている。これらの機能ブロックはハードウェア、ソフトウェアの組合せによっていろいろなかたちで実現できることは、当業者には理解されるところである。 The internal configuration of the diagnostic apparatus 100 is realized by elements and circuits such as a computer CPU and memory as a hardware configuration, and is realized by a computer program or the like as a software configuration, but in the figure, it is appropriately linked by them. It is drawn as a functional block to be realized. It is understood by those skilled in the art that these functional blocks can be realized in various forms by combining hardware and software.
　図３は、実施の形態に係る極低温装置１０の診断方法を示すフローチャートである。まず、低温側温度センサ５６と高温側温度センサ５８による温度測定が行われる（Ｓ１０）。診断装置１００は、低温側温度センサ５６から第１測定温度信号を受信し、低温側伝熱部材５０の測定温度Ｔａを取得する。また、診断装置１００は、高温側温度センサ５８から第２測定温度信号を受信し、高温側伝熱部材５２の測定温度Ｔｂを取得する。 FIG. 3 is a flowchart showing a diagnostic method of the ultra-low temperature device 10 according to the embodiment. First, the temperature is measured by the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 (S10). The diagnostic device 100 receives the first measured temperature signal from the low temperature side temperature sensor 56, and acquires the measured temperature Ta of the low temperature side heat transfer member 50. Further, the diagnostic apparatus 100 receives the second measured temperature signal from the high temperature side temperature sensor 58 and acquires the measured temperature Tb of the high temperature side heat transfer member 52.
　演算部１１０は、低温側伝熱部材５０の測定温度Ｔａと高温側伝熱部材５２の測定温度Ｔｂに基づいて、高温側伝熱部材５２から低温側伝熱部材５０に入る熱流量を演算する（Ｓ１２）。この熱流量の演算は、既知の方法を用いて行うことができる。例えば、演算部１１０は、低温側伝熱部材５０と高温側伝熱部材５２の測定された温度差（すなわち、Ｔｂ－Ｔａ）をまず演算し、得られた測定温度差と既知の関係に基づいて熱流量を演算する。この既知の関係は、低温側伝熱部材５０と高温側伝熱部材５２の温度差とこの温度差が生じているとき熱抵抗部材５４を流れる熱流量との関係を示すものであり、予め取得され、演算部１１０に保存されている。 The calculation unit 110 calculates the heat flow rate from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50 based on the measured temperature Ta of the low temperature side heat transfer member 50 and the measured temperature Tb of the high temperature side heat transfer member 52. (S12). This heat flow calculation can be performed using a known method. For example, the calculation unit 110 first calculates the measured temperature difference (that is, Tb-Ta) between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, and is based on the obtained measured temperature difference and a known relationship. And calculate the heat flow. This known relationship shows the relationship between the temperature difference between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 and the heat flow rate flowing through the thermal resistance member 54 when this temperature difference occurs, and is acquired in advance. It is stored in the calculation unit 110.
　異常検出部１２０は、演算部１１０によって演算された熱流量を熱流量しきい値Ｑｔｈと比較する（Ｓ１４）。熱流量しきい値Ｑｔｈは、極低温装置１０の運転を継続することが許容される熱流量の上限値Ｑｍａｘまたはそれより小さい値に設定される。この熱流量上限値Ｑｍａｘは、極低温装置１０が故障した（断熱性能が著しく劣化した）ものとみなされる熱流量の値であってもよい。よって、演算された熱流量がこの熱流量上限値Ｑｍａｘを超える場合には、極低温装置１０が故障したものとみなされるので、極低温装置１０の運転が停止されてもよい。熱流量しきい値Ｑｔｈが熱流量上限値Ｑｍａｘより小さい値に設定される実施形態では、演算された熱流量が熱流量しきい値Ｑｔｈを超え熱流量上限値Ｑｍａｘより小さい場合、極低温装置１０の運転を継続することが許容される。熱流量しきい値Ｑｔｈは、予め設定され、診断装置１００または異常検出部１２０に保存されている。熱流量しきい値Ｑｔｈは、設計者の経験的知見または設計者による実験やシミュレーション等に基づき適宜設定することが可能である。 The abnormality detection unit 120 compares the heat flow rate calculated by the calculation unit 110 with the heat flow rate threshold value Qth (S14). The heat flow threshold value Qth is set to a value equal to or smaller than the upper limit value Qmax of the heat flow rate at which the operation of the ultra-low temperature device 10 is allowed to continue. The heat flow rate upper limit value Qmax may be a value of the heat flow rate at which the ultra-low temperature device 10 is considered to have failed (insulation performance has been significantly deteriorated). Therefore, when the calculated heat flow rate exceeds the heat flow rate upper limit value Qmax, it is considered that the ultra-low temperature device 10 has failed, and the operation of the ultra-low temperature device 10 may be stopped. In the embodiment in which the heat flow rate threshold value Qth is set to a value smaller than the heat flow rate upper limit value Qmax, when the calculated heat flow rate exceeds the heat flow rate threshold value Qth and is smaller than the heat flow rate upper limit value Qmax, the ultra-low temperature device 10 It is permissible to continue the operation of. The heat flow threshold value Qth is set in advance and stored in the diagnostic device 100 or the abnormality detection unit 120. The heat flow threshold Qth can be appropriately set based on the empirical knowledge of the designer or experiments and simulations by the designer.
　異常検出部１２０は、例えば演算された熱流量が熱流量しきい値Ｑｔｈを超えるか否かを判定し、演算された熱流量が熱流量しきい値Ｑｔｈを超える場合（Ｓ１４のＹ）、真空容器３０の断熱性能の劣化を検出する（Ｓ１６）。この場合、真空容器３０の断熱性能の劣化に起因して、真空容器３０の外から輻射熱シールド４０へと熱が侵入し、その結果として、高温側伝熱部材５２から低温側伝熱部材５０への熱抵抗部材５４を通じた入熱が増加したものと考えられるからである。 The abnormality detection unit 120 determines, for example, whether or not the calculated heat flow rate exceeds the heat flow rate threshold value Qth, and when the calculated heat flow rate exceeds the heat flow rate threshold value Qth (Y in S14), vacuum. Deterioration of the heat insulating performance of the container 30 is detected (S16). In this case, due to the deterioration of the heat insulating performance of the vacuum container 30, heat enters the radiant heat shield 40 from the outside of the vacuum container 30, and as a result, the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50. This is because it is considered that the heat input through the thermal resistance member 54 of the above is increased.
　演算された熱流量が熱流量しきい値Ｑｔｈを超えない場合（Ｓ１４のＮ）、異常検出部１２０は、低温側伝熱部材５０の測定温度Ｔａを温度しきい値Ｔｔｈと比較する（Ｓ１８）。温度しきい値Ｔｔｈは、極低温冷凍機２０の冷却運転を継続することが許容される上限温度Ｔｍａｘまたはそれより低い値に設定される。この上限温度Ｔｍａｘは、極低温冷凍機２０が故障した（冷凍性能が著しく低下した）ものとみなされる温度値であってもよい。よって、測定温度Ｔａが上限温度Ｔｍａｘに達した場合には、極低温冷凍機２０が故障したものとみなされるので、極低温冷凍機２０の運転が停止されてもよい。温度しきい値Ｔｔｈが上限温度Ｔｍａｘより小さい値に設定される実施形態では、測定温度Ｔａが温度しきい値Ｔｔｈを超え上限温度Ｔｍａｘより低い場合、極低温冷凍機２０の運転を継続することが許容される。温度しきい値Ｔｔｈは、予め設定され、診断装置１００または異常検出部１２０に保存されている。温度しきい値Ｔｔｈは、設計者の経験的知見または設計者による実験やシミュレーション等に基づき適宜設定することが可能である。 When the calculated heat flow rate does not exceed the heat flow rate threshold value Qth (N in S14), the abnormality detection unit 120 compares the measured temperature Ta of the low temperature side heat transfer member 50 with the temperature threshold value Tth (S18). .. The temperature threshold value Tth is set to a value equal to or lower than the upper limit temperature Tmax at which the cooling operation of the ultra-low temperature refrigerator 20 is allowed to continue. The upper limit temperature Tmax may be a temperature value at which the ultra-low temperature refrigerator 20 is considered to have failed (the refrigerating performance is significantly deteriorated). Therefore, when the measured temperature Ta reaches the upper limit temperature Tmax, it is considered that the ultra-low temperature refrigerator 20 has failed, and the operation of the ultra-low temperature refrigerator 20 may be stopped. In the embodiment in which the temperature threshold value Tth is set to a value smaller than the upper limit temperature Tmax, when the measurement temperature Ta exceeds the temperature threshold value Tth and is lower than the upper limit temperature Tmax, the operation of the ultra-low temperature refrigerator 20 can be continued. Permissible. The temperature threshold value Tth is set in advance and stored in the diagnostic device 100 or the abnormality detection unit 120. The temperature threshold value Tth can be appropriately set based on the empirical knowledge of the designer or experiments and simulations by the designer.
　異常検出部１２０は、例えば低温側伝熱部材５０の測定温度Ｔａが温度しきい値Ｔｔｈより高いか否かを判定し、測定温度Ｔａが温度しきい値Ｔｔｈより高い場合（Ｓ１８のＹ）、極低温冷凍機２０の冷凍能力の低下を検出する（Ｓ２０）。この場合、演算された熱流量（すなわち高温側伝熱部材５２から低温側伝熱部材５０への熱抵抗部材５４を通じた入熱）が熱流量しきい値Ｑｔｈを下回るにもかかわらず、低温側伝熱部材５０の測定温度Ｔａが温度しきい値Ｔｔｈより高いことから、極低温冷凍機２０の冷凍能力が低下したものと考えられる。 The abnormality detection unit 120 determines, for example, whether or not the measured temperature Ta of the low temperature side heat transfer member 50 is higher than the temperature threshold Tth, and when the measured temperature Ta is higher than the temperature threshold Tth (Y in S18). A decrease in the refrigerating capacity of the ultra-low temperature refrigerating machine 20 is detected (S20). In this case, although the calculated heat flow rate (that is, heat input from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50 through the heat resistance member 54) is lower than the heat flow rate threshold Qth, the low temperature side Since the measured temperature Ta of the heat transfer member 50 is higher than the temperature threshold value Tth, it is considered that the refrigerating capacity of the ultra-low temperature refrigerator 20 has decreased.
　低温側伝熱部材５０の測定温度Ｔａが温度しきい値Ｔｔｈを超えない場合（Ｓ１８のＮ）、異常検出部１２０は、極低温装置１０は正常であると判定する（Ｓ２２）。この場合、低温側伝熱部材５０の測定温度Ｔａが温度しきい値Ｔｔｈを超えず、かつ演算された熱流量が熱流量しきい値Ｑｔｈを下回るので、真空容器３０の断熱性能も極低温冷凍機２０の冷凍能力も正常であるとみなすことができる。 When the measured temperature Ta of the low temperature side heat transfer member 50 does not exceed the temperature threshold value Tth (N in S18), the abnormality detection unit 120 determines that the extremely low temperature device 10 is normal (S22). In this case, since the measured temperature Ta of the low temperature side heat transfer member 50 does not exceed the temperature threshold Tth and the calculated heat flow rate is lower than the heat flow rate threshold Qth, the heat insulating performance of the vacuum vessel 30 is also extremely low temperature refrigeration. The refrigerating capacity of the machine 20 can also be regarded as normal.
　異常検出部１２０は、判定結果（および温度と熱流量の測定結果）を保存し、必要に応じて出力する。異常検出部１２０は、例えば診断装置１００に設けられた警告灯の点灯、またはその他の視覚的方法により、あるいは音声その他の報知手段により、異常を検出したことをユーザーに知らせてもよい。診断装置１００は、このような診断処理を定期的に（例えば月に一度）繰り返し実行する。 The abnormality detection unit 120 saves the determination result (and the measurement result of temperature and heat flow rate) and outputs it as necessary. The abnormality detection unit 120 may notify the user that an abnormality has been detected, for example, by lighting a warning light provided in the diagnostic apparatus 100, or by other visual method, or by voice or other notification means. The diagnostic apparatus 100 periodically (for example, once a month) repeatedly executes such a diagnostic process.
　実施の形態に係る極低温装置１０は、次のように動作する。極低温冷凍機２０が起動されると、極低温冷凍機２０の第１冷却ステージ２２ａは第１冷却温度に冷却され、第２冷却ステージ２２ｂは第２冷却温度に冷却される。輻射熱シールド４０は、第１冷却ステージ２２ａによって第１冷却温度に冷却される。正確には、第１冷却ステージ２２ａに組み込まれた熱流計のために、輻射熱シールド４０の冷却温度は第１冷却ステージ２２ａに比べて若干（例えば数Ｋ程度）高くなるが、これは実用上問題とはならない。超伝導コイル１２は、第２冷却ステージ２２ｂによって第２冷却温度に冷却される。図示されない電源から超伝導コイル１２に通電することにより、超伝導コイル１２は、強力な磁場を発生することができる。このようにして、極低温装置１０を運転することができる。 The ultra-low temperature device 10 according to the embodiment operates as follows. When the ultra-low temperature refrigerator 20 is started, the first cooling stage 22a of the ultra-low temperature refrigerator 20 is cooled to the first cooling temperature, and the second cooling stage 22b is cooled to the second cooling temperature. The radiant heat shield 40 is cooled to the first cooling temperature by the first cooling stage 22a. To be precise, the cooling temperature of the radiant heat shield 40 is slightly higher (for example, about several K) than that of the first cooling stage 22a due to the heat flow meter incorporated in the first cooling stage 22a, but this is a practical problem. It does not become. The superconducting coil 12 is cooled to the second cooling temperature by the second cooling stage 22b. By energizing the superconducting coil 12 from a power source (not shown), the superconducting coil 12 can generate a strong magnetic field. In this way, the ultra-low temperature device 10 can be operated.
　極低温装置を長期的に運用するなかで、例えば経年劣化により、極低温装置に故障が発生しうる。復旧するまで極低温装置の稼動は停止せざるを得ない。突然の故障の場合、復旧までにかかる時間は比較的長くなりがちである。しかし、もし、故障を予知し計画的にあらかじめ対処できたとすれば、影響を最小限にすることができる。 During long-term operation of the ultra-low temperature device, for example, aged deterioration may cause a failure in the ultra-low temperature device. The operation of the ultra-low temperature device has to be stopped until it is restored. In the case of a sudden failure, the time required for recovery tends to be relatively long. However, if the failure can be predicted and dealt with in advance in a planned manner, the impact can be minimized.
　既存技術では、極低温冷凍機の冷却温度をモニタすることによって極低温装置の故障を予知する試みがある。これは、極低温装置が長期の使用につれてだんだんと冷えにくくなり、冷却温度が長期的に少しずつ高まりうることに基づく。しかしながら、冷却温度は、累積の運転時間だけでなく、外部からの入熱など極低温装置の周囲環境、あるいは極低温装置の運転条件にも依存する。また、冷却温度は、累積の運転時間に応じて線形に変化するとは限らず、ある程度変動しうる。例えば、二段式の極低温冷凍機では、一段部の冷却温度は気温の季節変動の影響を比較的受けやすい。このような周囲環境の変化による温度上昇を、経年劣化による温度上昇と判別するのは必ずしも容易でない。現実には、冷却温度に基づく故障予知がうまく機能する場面は限定的である。 With existing technology, there is an attempt to predict the failure of the ultra-low temperature device by monitoring the cooling temperature of the ultra-low temperature refrigerator. This is based on the fact that the cryogenic device becomes harder to cool with long-term use, and the cooling temperature can gradually increase over the long term. However, the cooling temperature depends not only on the cumulative operating time but also on the ambient environment of the ultra-low temperature device such as heat input from the outside or the operating conditions of the ultra-low temperature device. Further, the cooling temperature does not always change linearly according to the cumulative operating time, but may fluctuate to some extent. For example, in a two-stage ultra-low temperature refrigerator, the cooling temperature of the first stage is relatively susceptible to seasonal fluctuations in temperature. It is not always easy to distinguish the temperature rise due to such changes in the surrounding environment from the temperature rise due to aging deterioration. In reality, there are only a limited number of situations where failure prediction based on cooling temperature works well.
　長期的に冷却温度が徐々に高まる主な原因は２つあり、１つは、真空容器の断熱性能が劣化したことによる入熱増加であり、もう１つは、極低温冷凍機の冷凍能力の低下である。ところが、温度上昇に基づく異常検出は、極低温装置のどこかに異常が起きたことを示すにすぎず、その原因となった異常発生箇所（例えば、極低温冷凍機で異常が起きたのか、あるいは真空容器で起きたのか）を直ちに特定するものではない。異常を解消する対策をとるために更なる検討を要することとなり、復旧に時間がかかってしまう。 There are two main causes for the gradual increase in cooling temperature over the long term, one is the increase in heat input due to the deterioration of the heat insulation performance of the vacuum vessel, and the other is the refrigerating capacity of the ultra-low temperature refrigerator. It is a decline. However, the abnormality detection based on the temperature rise only indicates that an abnormality has occurred somewhere in the ultra-low temperature device, and the location of the abnormality that caused the abnormality (for example, did the abnormality occur in the ultra-low temperature refrigerator? Or did it happen in a vacuum container?) Is not immediately specified. Further studies will be required to take measures to eliminate the abnormality, and recovery will take time.
　実施の形態に係る極低温装置１０によると、極低温冷凍機２０の第１冷却ステージ２２ａに熱流計が組み込まれている。これにより、高温側伝熱部材５２から低温側伝熱部材５０に入る熱流量を測定することができる。熱流量は、低温側伝熱部材５０と高温側伝熱部材５２の温度差に基づくので、既存の温度監視に比べて、周囲環境の影響を受けにくい。また、測定された熱流量に基づいて、温度上昇の原因が真空容器３０にあるのか、それとも極低温冷凍機２０にあるのかを特定することができる。このようにして、極低温装置１０の不具合の前兆を把握し、ユーザーに警告を出すことができる。必要な対処を事前にとることができる。したがって、冷却不良またはその兆候に効果的に対処することができる。 According to the ultra-low temperature device 10 according to the embodiment, a heat flow meter is incorporated in the first cooling stage 22a of the ultra-low temperature refrigerator 20. Thereby, the heat flow rate from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50 can be measured. Since the heat flow rate is based on the temperature difference between the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, it is less susceptible to the influence of the surrounding environment than the existing temperature monitoring. Further, based on the measured heat flow rate, it is possible to identify whether the cause of the temperature rise is the vacuum vessel 30 or the ultra-low temperature refrigerator 20. In this way, it is possible to grasp the precursor of the failure of the ultra-low temperature device 10 and issue a warning to the user. You can take necessary measures in advance. Therefore, poor cooling or its signs can be effectively dealt with.
　なお、温度しきい値Ｔｔｈは、高温側伝熱部材５２から低温側伝熱部材５０に入る熱流量に依存してもよい。入熱が増加すれば、低温側伝熱部材５０の測定温度Ｔａも増加しうる。よって、演算された熱流量が大きいほど、温度しきい値Ｔｔｈが増加されてもよい。このようにすれば、より正確な診断につながる。 The temperature threshold value Tth may depend on the heat flow rate from the high temperature side heat transfer member 52 to the low temperature side heat transfer member 50. If the heat input increases, the measured temperature Ta of the low temperature side heat transfer member 50 can also increase. Therefore, the larger the calculated heat flow rate, the more the temperature threshold value Tth may be increased. This will lead to a more accurate diagnosis.
　図４には、熱流量しきい値Ｑｔｈと温度しきい値Ｔｔｈの一例を示す。図４の縦軸は、極低温冷凍機２０の冷却温度を表し、横軸は、極低温冷凍機２０への熱流量を示す。極低温冷凍機２０は、固有の性能として、能力曲線８０とも呼ばれる入熱と冷却温度の関係を有する。能力曲線８０は、極低温冷凍機２０（例えば第１冷却ステージ２２ａ）への入熱が増えるほど冷却温度も高まることを示す。そこで、この能力曲線の上下に許容幅８２を設定し、この許容幅８２の上限値を温度しきい値Ｔｔｈとして用いてもよい。同じ図上に、毎回の測定結果（演算された熱流量と低温側伝熱部材５０の測定温度Ｔａの組み合わせ）の履歴を矢印で例示する。図示されるように、熱流量が熱流量しきい値Ｑｔｈを下回るにもかかわらず、熱流量と測定温度Ｔａの組み合わせが許容幅８２から上方に逸脱した場合には、極低温冷凍機２０の冷凍能力が低下したとみなすことができる。なお、熱流量が熱流量しきい値Ｑｔｈを超える場合には、上述のように、真空容器３０の断熱性能が劣化したとみなされる。 FIG. 4 shows an example of the heat flow threshold Qth and the temperature threshold Tth. The vertical axis of FIG. 4 represents the cooling temperature of the ultra-low temperature refrigerator 20, and the horizontal axis represents the heat flow rate to the ultra-low temperature refrigerator 20. The ultra-low temperature refrigerator 20 has a relationship between heat input and cooling temperature, which is also called a capacity curve 80, as a unique performance. The capacity curve 80 shows that the cooling temperature increases as the heat input to the ultra-low temperature refrigerator 20 (for example, the first cooling stage 22a) increases. Therefore, the permissible width 82 may be set above and below the capacity curve, and the upper limit value of the permissible width 82 may be used as the temperature threshold value Tth. On the same figure, the history of each measurement result (combination of the calculated heat flow rate and the measured temperature Ta of the low temperature side heat transfer member 50) is illustrated by an arrow. As shown in the figure, when the combination of the heat flow rate and the measurement temperature Ta deviates upward from the allowable width 82 even though the heat flow rate is lower than the heat flow rate threshold value Qth, the freezing of the ultra-low temperature refrigerator 20 is performed. It can be considered that the ability has decreased. When the heat flow rate exceeds the heat flow rate threshold value Qth, it is considered that the heat insulating performance of the vacuum container 30 has deteriorated as described above.
　以上、本発明を実施例にもとづいて説明した。本発明は上記実施形態に限定されず、種々の設計変更が可能であり、様々な変形例が可能であること、またそうした変形例も本発明の範囲にあることは、当業者に理解されるところである。ある実施の形態に関連して説明した種々の特徴は、他の実施の形態にも適用可能である。組合せによって生じる新たな実施の形態は、組み合わされる実施の形態それぞれの効果をあわせもつ。 The present invention has been described above based on examples. It will be understood by those skilled in the art that the present invention is not limited to the above embodiment, various design changes are possible, various modifications are possible, and such modifications are also within the scope of the present invention. By the way. The various features described in relation to one embodiment are also applicable to other embodiments. The new embodiments resulting from the combination have the effects of each of the combined embodiments.
　図５は、実施の形態に係る熱流計の他の一例を模式的に示す部分斜視図である。低温側伝熱部材５０、高温側伝熱部材５２、および熱抵抗部材５４は、Ｃ字状であってもよい。熱抵抗部材５４は、低温側伝熱部材５０と高温側伝熱部材５２それぞれの周に沿って低温側伝熱部材５０と高温側伝熱部材５２に接合されてもよい。Ｃ字状の形状の両端間の隙間６８は、例えば数ｍｍ程度とされ、温度センサ配線６０を通すために利用されてもよい。配線被覆の損傷を防ぐために、低温側伝熱部材５０、高温側伝熱部材５２、および熱抵抗部材５４のエッジや角は丸くしてもよい。この隙間６８は、図２を参照して説明した低温側温度センサ取付部６４および高温側温度センサ取付部６６とは反対側に設けられてもよい。 FIG. 5 is a partial perspective view schematically showing another example of the heat flow meter according to the embodiment. The low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the thermal resistance member 54 may be C-shaped. The thermal resistance member 54 may be joined to the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52 along the circumferences of the low temperature side heat transfer member 50 and the high temperature side heat transfer member 52, respectively. The gap 68 between both ends of the C-shape is, for example, about several mm, and may be used for passing the temperature sensor wiring 60. In order to prevent damage to the wiring coating, the edges and corners of the low temperature side heat transfer member 50, the high temperature side heat transfer member 52, and the thermal resistance member 54 may be rounded. The gap 68 may be provided on the side opposite to the low temperature side temperature sensor mounting portion 64 and the high temperature side temperature sensor mounting portion 66 described with reference to FIG.
　図６は、実施の形態に係る熱流計を模式的に示す図である。この熱流計は、極低温冷凍機２０（極低温冷凍機２０の第１冷却ステージ２２ａ）から被冷却物（例えば輻射熱シールド４０）への伝熱経路に設置される。図６に示される実施形態では、図１に示される実施形態とは異なり、熱流計が極低温冷凍機２０の第１冷却ステージ２２ａから取り外し可能に取り付けられる。 FIG. 6 is a diagram schematically showing a heat flow meter according to an embodiment. This heat flow meter is installed in the heat transfer path from the ultra-low temperature refrigerator 20 (first cooling stage 22a of the ultra-low temperature refrigerator 20) to the object to be cooled (for example, the radiant heat shield 40). In the embodiment shown in FIG. 6, unlike the embodiment shown in FIG. 1, the heat flow meter is detachably attached from the first cooling stage 22a of the cryogenic refrigerator 20.
　低温側伝熱部材、この例では第１冷却ステージ２２ａは、伝熱経路上で極低温冷凍機２０側に設けられる。高温側伝熱部材、この例では輻射熱シールド４０は、伝熱経路上で被冷却側に設けられ、第１冷却ステージ２２ａから離間して配置される。熱抵抗部材５４は、第１冷却ステージ２２ａと輻射熱シールド４０の間に挟み込まれた状態で配置され、第１冷却ステージ２２ａと輻射熱シールド４０の熱接触を媒介する。第１冷却ステージ２２ａと輻射熱シールド４０は、ボルトなどの締結部材によって互いに締結され、それにより、熱抵抗部材５４が両者間に挟み込まれてもよい。熱抵抗部材５４は、環状またはＣ字状のリング形状の薄板（例えば厚さ０．３ｍｍから１ｍｍ）であってもよく、例えばシムリングであってもよい。図７に示されるように、熱抵抗部材５４は、熱接触する面積を増加させるために、径方向に比較的厚い幅をもつリング形状を有してもよく、締結部材のための通し穴７０を有してもよい。 The low temperature side heat transfer member, in this example, the first cooling stage 22a is provided on the extremely low temperature refrigerator 20 side on the heat transfer path. The high temperature side heat transfer member, in this example, the radiant heat shield 40 is provided on the heat transfer path on the cooled side and is arranged away from the first cooling stage 22a. The thermal resistance member 54 is arranged in a state of being sandwiched between the first cooling stage 22a and the radiant heat shield 40, and mediates the thermal contact between the first cooling stage 22a and the radiant heat shield 40. The first cooling stage 22a and the radiant heat shield 40 may be fastened to each other by a fastening member such as a bolt, whereby the thermal resistance member 54 may be sandwiched between the two. The thermal resistance member 54 may be an annular or C-shaped ring-shaped thin plate (for example, a thickness of 0.3 mm to 1 mm), or may be a shim ring, for example. As shown in FIG. 7, the thermal resistance member 54 may have a ring shape having a relatively thick radial width in order to increase the area of thermal contact, and the through hole 70 for the fastening member. May have.
　低温側温度センサ５６は、第１冷却ステージ２２ａに取り付けられ、第１冷却ステージ２２ａの温度を測定する。高温側温度センサ５８は、輻射熱シールド４０に取り付けられ、輻射熱シールド４０の温度を測定する。低温側温度センサ５６と高温側温度センサ５８は、上述の実施の形態と同様に、診断装置１００に接続されてもよい。このようにしても、上述の実施の形態と同様に、熱流計を構成することができる。 The low temperature side temperature sensor 56 is attached to the first cooling stage 22a and measures the temperature of the first cooling stage 22a. The high temperature side temperature sensor 58 is attached to the radiant heat shield 40 and measures the temperature of the radiant heat shield 40. The low temperature side temperature sensor 56 and the high temperature side temperature sensor 58 may be connected to the diagnostic device 100 in the same manner as in the above-described embodiment. Even in this way, the heat flow meter can be configured in the same manner as in the above-described embodiment.
　なお、熱抵抗部材５４は、第１冷却ステージ２２ａに接続された他の低温側伝熱部材と、輻射熱シールド４０などの被冷却物に接続された他の高温側伝熱部材との間に挟み込まれ、熱流計を構成してもよい。 The thermal resistance member 54 is sandwiched between another low temperature side heat transfer member connected to the first cooling stage 22a and another high temperature side heat transfer member connected to a object to be cooled such as the radiant heat shield 40. A heat transfer meter may be configured.
　上述の実施の形態では、二段式の極低温冷凍機２０の第１冷却ステージ２２ａに熱流計を組み込んでいるが、これに代えてまたはこれとともに、第２冷却ステージ２２ｂに熱流計が組み込まれてもよい。あるいは、実施の形態に係る熱流計は、単段式の極低温冷凍機の冷却ステージに組み込まれてもよい。 In the above-described embodiment, the heat flow meter is incorporated in the first cooling stage 22a of the two-stage ultra-low temperature refrigerator 20, but instead of or together with this, the heat flow meter is incorporated in the second cooling stage 22b. You may. Alternatively, the heat flow meter according to the embodiment may be incorporated in a cooling stage of a single-stage ultra-low temperature refrigerator.
　上述の実施の形態では、極低温装置１０は、診断装置１００を備え、温度測定と熱流量演算、およびそれに基づく異常検出を自動的に実行するように構成されているが、ある実施の形態では、極低温装置１０は、診断装置１００を備えなくてもよい。この場合、低温側温度センサ５６と高温側温度センサ５８の温度測定結果から熱流量を手計算で求め、異常の有無を人手で判断してもよい。 In the above-described embodiment, the cryogenic device 10 includes a diagnostic device 100 and is configured to automatically perform temperature measurement, heat flow calculation, and abnormality detection based on the temperature measurement, but in one embodiment. The ultra-low temperature device 10 does not have to include the diagnostic device 100. In this case, the heat flow rate may be manually calculated from the temperature measurement results of the low temperature side temperature sensor 56 and the high temperature side temperature sensor 58, and the presence or absence of an abnormality may be manually determined.
　実施の形態にもとづき、具体的な語句を用いて本発明を説明したが、実施の形態は、本発明の原理、応用の一側面を示しているにすぎず、実施の形態には、請求の範囲に規定された本発明の思想を逸脱しない範囲において、多くの変形例や配置の変更が認められる。 The present invention has been described using specific terms and phrases based on the embodiments, but the embodiments show only one aspect of the principles and applications of the present invention, and the embodiments are claimed. Many modifications and arrangement changes are permitted within the range not deviating from the idea of the present invention defined in the scope.
　本発明は、熱流計を組み込んだ極低温冷凍機、およびこれを備える極低温装置の分野における利用が可能である。また、本発明は、極低温冷凍機から被冷却物への伝熱経路に設置される熱流計、およびこれを備える極低温装置の分野における利用が可能である。 The present invention can be used in the field of an ultra-low temperature refrigerator incorporating a heat flow meter and an ultra-low temperature device equipped with the refrigerator. Further, the present invention can be used in the field of a heat flow meter installed in a heat transfer path from an ultra-low temperature refrigerator to an object to be cooled, and an ultra-low temperature device including the heat flow meter.
　１０　極低温装置、　２０　極低温冷凍機、　２２　冷却ステージ、　３０　真空容器、　５０　低温側伝熱部材、　５２　高温側伝熱部材、　５４　熱抵抗部材、　５６　低温側温度センサ、　５８　高温側温度センサ、　６４　低温側温度センサ取付部、　６６　高温側温度センサ取付部、　１１０　演算部、　１２０　異常検出部。 10 ultra-low temperature device, 20 ultra-low temperature refrigerator, 22 cooling stage, 30 vacuum container, 50 low temperature side heat transfer member, 52 high temperature side heat transfer member, 54 heat resistance member, 56 low temperature side temperature sensor, 58 high temperature side temperature sensor, 64 Low temperature side temperature sensor mounting unit, 66 High temperature side temperature sensor mounting unit, 110 Calculation unit, 120 Abnormality detection unit.

Claims (17)

  1. 　離間配置された低温側伝熱部材および高温側伝熱部材と、前記低温側伝熱部材と前記高温側伝熱部材を接続し、前記低温側伝熱部材と前記高温側伝熱部材の熱接触を媒介する熱抵抗部材とを有する冷却ステージと、
    　前記低温側伝熱部材に取り付けられ、前記低温側伝熱部材の温度を測定する低温側温度センサと、
    　前記高温側伝熱部材に取り付けられ、前記高温側伝熱部材の温度を測定する高温側温度センサと、を備えることを特徴とする極低温冷凍機。     The low temperature side heat transfer member and the high temperature side heat transfer member, the low temperature side heat transfer member and the high temperature side heat transfer member are connected to each other, and the low temperature side heat transfer member and the high temperature side heat transfer member are in thermal contact with each other. With a cooling stage having a heat resistance member that mediates
    A low temperature side temperature sensor attached to the low temperature side heat transfer member and measuring the temperature of the low temperature side heat transfer member,
    An ultra-low temperature refrigerator provided with a high temperature side temperature sensor attached to the high temperature side heat transfer member and measuring the temperature of the high temperature side heat transfer member.
  2. 　前記低温側温度センサによって測定される前記低温側伝熱部材の温度と前記高温側温度センサによって測定される前記高温側伝熱部材の温度に基づいて、前記高温側伝熱部材から前記低温側伝熱部材に入る熱流量を演算する演算部をさらに備えることを特徴とする請求項１に記載の極低温冷凍機。 From the high temperature side heat transfer member to the low temperature side heat transfer member based on the temperature of the low temperature side heat transfer member measured by the low temperature side temperature sensor and the temperature of the high temperature side heat transfer member measured by the high temperature side temperature sensor. The ultra-low temperature refrigerator according to claim 1, further comprising a calculation unit for calculating the heat flow rate entering the heat member.
  3. 　前記極低温冷凍機は、前記冷却ステージが真空容器内に配置されるようにして前記真空容器に設置可能であり、
    　前記演算部によって演算された前記熱流量を熱流量しきい値と比較し、前記熱流量が前記熱流量しきい値を超える場合に前記真空容器の断熱性能の劣化を検出する異常検出部をさらに備えることを特徴とする請求項２に記載の極低温冷凍機。     The cryogenic refrigerator can be installed in the vacuum vessel so that the cooling stage is arranged in the vacuum vessel.
    An abnormality detection unit that compares the heat flow rate calculated by the calculation unit with the heat flow rate threshold value and detects deterioration of the heat insulation performance of the vacuum vessel when the heat flow rate exceeds the heat flow rate threshold value is further provided. The ultra-low temperature refrigerator according to claim 2, wherein the refrigerator is provided.
  4. 　前記異常検出部は、前記熱流量を前記熱流量しきい値より大きい熱流量上限値と比較し、前記熱流量が前記熱流量しきい値を超え前記熱流量上限値より小さい場合、前記極低温冷凍機の運転を継続することを特徴とする請求項３に記載の極低温冷凍機。 The abnormality detection unit compares the heat flow rate with a heat flow rate upper limit value larger than the heat flow rate threshold value, and when the heat flow rate exceeds the heat flow rate threshold value and is smaller than the heat flow rate upper limit value, the extremely low temperature The ultra-low temperature refrigerator according to claim 3, wherein the operation of the refrigerator is continued.
  5. 　前記異常検出部は、前記熱流量が前記熱流量上限値を超える場合、前記極低温冷凍機の運転を停止することを特徴とする請求項４に記載の極低温冷凍機。 The ultra-low temperature refrigerator according to claim 4, wherein the abnormality detection unit stops the operation of the ultra-low temperature refrigerator when the heat flow rate exceeds the heat flow upper limit value.
  6. 　前記異常検出部は、前記低温側温度センサによって測定される前記低温側伝熱部材の温度を温度しきい値と比較し、前記低温側伝熱部材の温度が前記温度しきい値より高くかつ前記熱流量が前記熱流量しきい値を下回る場合に前記極低温冷凍機の冷凍能力の低下を検出することを特徴とする請求項３から５のいずれかに記載の極低温冷凍機。 The abnormality detecting unit compares the temperature of the low temperature side heat transfer member measured by the low temperature side temperature sensor with the temperature threshold value, and the temperature of the low temperature side heat transfer member is higher than the temperature threshold value and said. The ultra-low temperature refrigerating machine according to any one of claims 3 to 5, wherein a decrease in the refrigerating capacity of the ultra-low temperature refrigerating machine is detected when the heat flow rate is lower than the heat flow rate threshold value.
  7. 　前記演算部によって演算された前記熱流量を熱流量しきい値と比較し、前記低温側温度センサによって測定される前記低温側伝熱部材の温度を温度しきい値と比較し、前記低温側伝熱部材の温度が前記温度しきい値より高くかつ前記熱流量が前記熱流量しきい値を下回る場合に前記極低温冷凍機の冷凍能力の低下を検出する異常検出部をさらに備えることを特徴とする請求項２に記載の極低温冷凍機。 The heat flow rate calculated by the calculation unit is compared with the heat flow rate threshold value, the temperature of the low temperature side heat transfer member measured by the low temperature side temperature sensor is compared with the temperature threshold value, and the low temperature side heat transfer is performed. It is further provided with an abnormality detecting unit for detecting a decrease in the refrigerating capacity of the ultra-low temperature refrigerator when the temperature of the heat member is higher than the temperature threshold and the heat flow rate is lower than the heat flow rate threshold. The ultra-low temperature refrigerator according to claim 2.
  8. 　前記異常検出部は、前記低温側伝熱部材の温度を前記温度しきい値より高い上限温度と比較し、前記低温側伝熱部材の温度が前記温度しきい値より高く前記上限温度より低い場合、前記極低温冷凍機の運転を継続することを特徴とする請求項６または７に記載の極低温冷凍機。 The abnormality detection unit compares the temperature of the low temperature side heat transfer member with the upper limit temperature higher than the temperature threshold, and when the temperature of the low temperature side heat transfer member is higher than the temperature threshold and lower than the upper limit temperature. The ultra-low temperature refrigerating machine according to claim 6 or 7, wherein the operation of the ultra-low temperature refrigerating machine is continued.
  9. 　前記異常検出部は、前記低温側伝熱部材の温度が前記上限温度に達した場合、前記極低温冷凍機の運転を停止することを特徴とする請求項８に記載の極低温冷凍機。 The ultra-low temperature refrigerator according to claim 8, wherein the abnormality detecting unit stops the operation of the ultra-low temperature refrigerator when the temperature of the low temperature side heat transfer member reaches the upper limit temperature.
  10. 　前記温度しきい値は、前記高温側伝熱部材から前記低温側伝熱部材に入る熱流量に依存することを特徴とする請求項６から９のいずれかに記載の極低温冷凍機。 The ultra-low temperature refrigerator according to any one of claims 6 to 9, wherein the temperature threshold depends on the heat flow rate from the high temperature side heat transfer member to the low temperature side heat transfer member.
  11. 　前記低温側伝熱部材、前記高温側伝熱部材、および前記熱抵抗部材は、環状またはＣ字状であり、前記熱抵抗部材は、前記低温側伝熱部材と前記高温側伝熱部材それぞれの周に沿って前記低温側伝熱部材と前記高温側伝熱部材に接合されていることを特徴とする請求項１から１０のいずれかに記載の極低温冷凍機。 The low temperature side heat transfer member, the high temperature side heat transfer member, and the heat resistance member are annular or C-shaped, and the heat resistance member is each of the low temperature side heat transfer member and the high temperature side heat transfer member. The ultra-low temperature refrigerator according to any one of claims 1 to 10, wherein the low temperature side heat transfer member and the high temperature side heat transfer member are joined along the circumference.
  12. 　前記低温側伝熱部材、前記高温側伝熱部材、および前記熱抵抗部材は、Ｃ字状であり、前記低温側温度センサまたは前記高温側温度センサから延びる温度センサ配線が前記Ｃ字状の形状の両端間の隙間に挿通されることを特徴とする請求項１１に記載の極低温冷凍機。 The low temperature side heat transfer member, the high temperature side heat transfer member, and the heat resistance member are C-shaped, and the temperature sensor wiring extending from the low temperature side temperature sensor or the high temperature side temperature sensor has the C shape. The ultra-low temperature refrigerating machine according to claim 11, wherein the ultra-low temperature refrigerating machine is inserted into a gap between both ends of the above.
  13. 　真空容器に装着される装着フランジをさらに備え、
    　前記装着フランジは、前記低温側温度センサまたは前記高温側温度センサから延びる温度センサ配線を前記真空容器の外に引き出す真空フィードスルーを備えることを特徴とする請求項１から１２のいずれかに記載の極低温冷凍機。     Further equipped with a mounting flange to be mounted on the vacuum container,
    13. Very low temperature freezer.
  14. 　前記冷却ステージは、前記低温側伝熱部材と前記高温側伝熱部材の温度差が０．５Ｋから５Ｋの範囲にあるように構成されることを特徴とする請求項１から１３のいずれかに記載の極低温冷凍機。 The cooling stage according to any one of claims 1 to 13, wherein the cooling stage is configured such that the temperature difference between the low temperature side heat transfer member and the high temperature side heat transfer member is in the range of 0.5K to 5K. The ultra-low temperature refrigerator described.
  15. 　前記熱抵抗部材は、前記低温側伝熱部材および前記高温側伝熱部材に比べて熱伝導率の低い材料で形成されることを特徴とする請求項１から１４のいずれかに記載の極低温冷凍機。 The ultra-low temperature according to any one of claims 1 to 14, wherein the thermal resistance member is made of a material having a lower thermal conductivity than the low temperature side heat transfer member and the high temperature side heat transfer member. refrigerator.
  16. 　離間配置された低温側伝熱部材および高温側伝熱部材と、前記低温側伝熱部材と前記高温側伝熱部材を接続し、前記低温側伝熱部材と前記高温側伝熱部材の熱接触を媒介する熱抵抗部材とを有する冷却ステージを備え、
    　前記低温側伝熱部材には、低温側温度センサ取付部が設けられ、前記高温側伝熱部材には、高温側温度センサ取付部が設けられていることを特徴とする極低温冷凍機。     The low temperature side heat transfer member and the high temperature side heat transfer member, the low temperature side heat transfer member and the high temperature side heat transfer member are connected to each other, and the low temperature side heat transfer member and the high temperature side heat transfer member are in thermal contact with each other. Equipped with a cooling stage with a heat resistance member that mediates
    An ultra-low temperature refrigerator characterized in that the low temperature side heat transfer member is provided with a low temperature side temperature sensor mounting portion, and the high temperature side heat transfer member is provided with a high temperature side temperature sensor mounting portion.
  17. 　極低温冷凍機から被冷却物への伝熱経路に設置される熱流計であって、
    　前記伝熱経路上で極低温冷凍機側に設けられる低温側伝熱部材と、
    　前記伝熱経路上で被冷却側に設けられ、前記低温側伝熱部材から離間して配置される高温側伝熱部材と、
    　前記低温側伝熱部材と前記高温側伝熱部材の間に挟み込まれた状態で配置され、前記低温側伝熱部材と前記高温側伝熱部材の熱接触を媒介する熱抵抗部材と、
    　前記低温側伝熱部材に取り付けられ、前記低温側伝熱部材の温度を測定する低温側温度センサと、
    　前記高温側伝熱部材に取り付けられ、前記高温側伝熱部材の温度を測定する高温側温度センサと、を備えることを特徴とする熱流計。     It is a heat flow meter installed in the heat transfer path from the ultra-low temperature freezer to the object to be cooled.
    A low-temperature side heat transfer member provided on the ultra-low temperature refrigerator side on the heat transfer path,
    A high-temperature side heat transfer member provided on the cooled side on the heat transfer path and arranged apart from the low-temperature side heat transfer member.
    A heat resistance member which is arranged in a state of being sandwiched between the low temperature side heat transfer member and the high temperature side heat transfer member and mediates the thermal contact between the low temperature side heat transfer member and the high temperature side heat transfer member.
    A low temperature side temperature sensor attached to the low temperature side heat transfer member and measuring the temperature of the low temperature side heat transfer member,
    A heat flow meter including a high temperature side temperature sensor attached to the high temperature side heat transfer member and measuring the temperature of the high temperature side heat transfer member.
PCT/JP2021/044121 2020-12-11 2021-12-01 Cryogenic refrigerator and heat flow meter WO2022124162A1 (en)

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JP2000097512A (en) * 1998-09-25 2000-04-04 Hitachi Building Equipment Engineering Co Ltd Method for increasing heating capacity of absorption- water cooled/warmer and increasing load absorption water cooler/warmer
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02282667A (en) * 1989-04-24 1990-11-20 Matsushita Electric Ind Co Ltd Control device for multi-heat pump
JP2000097512A (en) * 1998-09-25 2000-04-04 Hitachi Building Equipment Engineering Co Ltd Method for increasing heating capacity of absorption- water cooled/warmer and increasing load absorption water cooler/warmer
JP2005121323A (en) * 2003-10-17 2005-05-12 Sharp Corp Stirling engine and heat exchange system
JP2006038314A (en) * 2004-07-26 2006-02-09 Sharp Corp Stirling refrigerating machine, and cooler mounted therewith
JP2012209381A (en) * 2011-03-29 2012-10-25 Toshiba Corp Superconductive magnet device
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