US20240125548A1 - Oil-lubricated cryocooler compressor and operation method thereof - Google Patents
Oil-lubricated cryocooler compressor and operation method thereof Download PDFInfo
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- US20240125548A1 US20240125548A1 US18/488,987 US202318488987A US2024125548A1 US 20240125548 A1 US20240125548 A1 US 20240125548A1 US 202318488987 A US202318488987 A US 202318488987A US 2024125548 A1 US2024125548 A1 US 2024125548A1
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Images
Classifications
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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
- F25B9/14—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
-
- 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
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
- F25J1/0279—Compression of refrigerant or internal recycle fluid, e.g. kind of compressor, accumulator, suction drum etc.
- F25J1/0298—Safety aspects and control of the refrigerant compression system, e.g. anti-surge control
-
- 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
- F25B31/00—Compressor arrangements
- F25B31/002—Lubrication
- F25B31/004—Lubrication oil recirculating arrangements
-
- 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
- F25B31/00—Compressor arrangements
- F25B31/006—Cooling of compressor or motor
-
- 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
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
- F25B9/14—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
- F25B9/145—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle pulse-tube cycle
-
- 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
- F25J—LIQUEFACTION, SOLIDIFICATION OR SEPARATION OF GASES OR GASEOUS OR LIQUEFIED GASEOUS MIXTURES BY PRESSURE AND COLD TREATMENT OR BY BRINGING THEM INTO THE SUPERCRITICAL STATE
- F25J1/00—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures
- F25J1/02—Processes or apparatus for liquefying or solidifying gases or gaseous mixtures requiring the use of refrigeration, e.g. of helium or hydrogen ; Details and kind of the refrigeration system used; Integration with other units or processes; Controlling aspects of the process
- F25J1/0243—Start-up or control of the process; Details of the apparatus used; Details of the refrigerant compression system used
- F25J1/0244—Operation; Control and regulation; Instrumentation
- F25J1/0254—Operation; Control and regulation; Instrumentation controlling particular process parameter, e.g. pressure, temperature
-
- 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
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/004—Gas cycle refrigeration machines using a compressor of the rotary type
Abstract
An oil-lubricated cryocooler compressor that compresses a refrigerant gas of a cryocooler includes a liquid-cooled heat exchanger that cools the refrigerant gas and/or an oil through heat exchange with a coolant and a cooling controller that is configured to acquire a supply temperature of the coolant supplied to the liquid-cooled heat exchanger and to control a flow rate of the coolant of the liquid-cooled heat exchanger and/or an exhaust heat amount of the cryocooler compressor based on the acquired supply temperature of the coolant.
Description
- This application claims priority to Japanese Patent Application No. 2022-167002, filed on Oct. 18, 2022, which is incorporated by reference herein in its entirety.
- A certain embodiment of the present invention relates to an oil-lubricated cryocooler compressor and an operation method thereof.
- An oil-lubricated helium compressor with a dual aftercooler is proposed (for example, refer to the related art). Two aftercoolers that cool helium and an oil, that is, a water-cooled aftercooler and an air-cooled aftercooler are incorporated in the compressor. The air-cooled aftercooler is disposed in series or in parallel with the water-cooled aftercooler. By operating a fan of the air-cooled aftercooler, redundancy in a case where a cooling water circuit of the water-cooled aftercooler is blocked is provided.
- According to an embodiment of the present invention, there is provided an oil-lubricated cryocooler compressor that compresses a refrigerant gas of a cryocooler. The cryocooler compressor includes a liquid-cooled heat exchanger that cools the refrigerant gas and/or an oil through heat exchange with a coolant and a cooling controller that is configured to acquire a supply temperature of the coolant supplied to the liquid-cooled heat exchanger and to control a flow rate of the coolant of the liquid-cooled heat exchanger and/or an exhaust heat amount of the cryocooler compressor based on the acquired supply temperature of the coolant.
- According to another embodiment of the present invention, there is provided an operation method of an oil-lubricated cryocooler compressor that compresses a refrigerant gas of a cryocooler. The cryocooler compressor includes a liquid-cooled heat exchanger that cools the refrigerant gas and/or an oil through heat exchange with a coolant. The method includes acquiring a supply temperature of the coolant supplied to the liquid-cooled heat exchanger and controlling a flow rate of the coolant of the liquid-cooled heat exchanger and/or an exhaust heat amount of the cryocooler compressor based on the acquired supply temperature of the coolant.
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FIG. 1 is a diagram schematically showing a cryogenic device according to an embodiment of the present invention. -
FIG. 2 is a diagram schematically showing a cryocooler according to the embodiment. -
FIG. 3 is a diagram schematically showing another example of a cooling controller according to the embodiment. -
FIG. 4 is a diagram schematically showing still another example of the cooling controller according to the embodiment. -
FIG. 5 is a diagram schematically showing still another example of the cooling controller according to the embodiment. - A cryocooler is often used in cryogenic cooling for a cryogenic device that operates at a cryogenic temperature, such as a superconducting magnet. The cryogenic device can include various devices that generate heat, like a compressor of the cryocooler. Such heat generating devices are frequently cooled by a common cooler attached to the cryogenic device. The cooler can typically take a form of supplying a coolant to each heat generating device, such as an air-cooled chiller.
- The cooling capacity of the cooler can be affected by an external factor such as an environment temperature. For example, in a case where the environment temperature is high such as in summer, the cooling capacity can be significantly decreased compared with a case where the temperature is low such as in winter (for example, in the case of the air-cooled chiller, the decrease reaches several tens of % in some cases). There is a concern about a risk of the cooling capacity of the cooler becoming tight or insufficient due to such an external factor or a variety of factors such as an increase in heat generation attributable to an operation situation of the cryogenic device. In a case where the temperature of the heat generating device rises excessively due to cooling capacity insufficiency, there is a concern that a deterioration in the performance of the device or an abnormal operation occurs. This can undesirably prevent the cryogenic device from operating.
- It is desirable to provide a cryocooler compressor that makes load reduction of a cooler possible.
- Any combination of the components described above and a combination obtained by switching the components and expressions of the present invention between methods, devices, and systems are also effective as an embodiment of the present invention.
- With the present invention, the cryocooler compressor that makes load reduction of the cooler possible can be provided.
- Hereinafter, an embodiment 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 processing will be assigned with the same reference symbols, and redundant description thereof will be omitted as appropriate. The scales and shapes of shown parts are set for convenience in order to make the description easy to understand and are not to be understood as limiting unless stated otherwise. The embodiment is merely an example and does not limit the scope of the present invention. All characteristics and combinations to be described in the embodiment are not necessarily essential to the invention.
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FIG. 1 is a diagram schematically showing acryogenic device 100 according to the embodiment. Thecryogenic device 100 may be, for example, a superconducting magnet device. The superconducting magnet device is mounted on, for example, a high magnetic field using device as a magnetic field source of an accelerator such as a single crystal pulling device, a nuclear magnetic resonance (NMR) system, a magnetic resonance imaging (MRI) system, and a cyclotron, a high energy physical system such as a nuclear fusion system, or other high magnetic field using devices (not shown) and can generate a high magnetic field required for the devices. - The
cryogenic device 100 includes acryocooler 10 for cryogenic cooling of the superconducting magnet. Thecryocooler 10 includes an oil-lubricated cryocooler compressor (hereinafter, also simply referred to as a compressor) 12 and acold head 14. - The
compressor 12 generates compression heat when a refrigerant gas is compressed. In addition, thecryogenic device 100 can include at least one of devices 102_1 to 102_n that can generate heat, in addition to thecompressor 12. For example, in a case where thecryogenic device 100 is an MRI system (or a part thereof), the device 102 can include a gradient magnetic field coil, a gradient magnetic field amplifier, and an RF amplifier. - In order to cool the device 102 that can generate heat, the
cryogenic device 100 is provided with acooler 110 configured to control the temperature of a coolant and to circulate the coolant, including thecompressor 12. Thecooler 110 is shared by thecompressor 12 and the device 102. The cooler 110 is, for example, a chiller and may be, for example, an air-cooled or other cooling type chiller. As an exemplary configuration, thecooler 110 is configured to supply a coolant (for example, cooling water) to aheat exchanger 104 provided at thecryogenic device 100. In addition, thecooler 110 is configured to collect the coolant used in cooling from theheat exchanger 104 and to cool again. - A
coolant line 106 of each of thecompressor 12 and the device 102 is connected to theheat exchanger 104. Heat exchange between a coolant supplied and cooled from the cooler 110 and a coolant of thecoolant line 106 is performed by theheat exchanger 104, and thereby the coolant of thecoolant line 106 is cooled. The coolant is supplied to thecompressor 12 and the device 102 and cools thecompressor 12 and the device 102. The coolant used in cooling is collected to theheat exchanger 104 through thecoolant line 106 and is again cooled. -
FIG. 2 is a diagram schematically showing thecryocooler 10 according to the embodiment. - The
compressor 12 is configured to collect a refrigerant gas of thecryocooler 10 from thecold head 14, to pressurize the collected refrigerant gas, and to supply the refrigerant gas to thecold head 14 again. Thecompressor 12 is also referred to as a compressor unit. Thecold head 14 is also referred to as an expander and includes aroom temperature section 14 a and a low-temperature section 14 b which is also referred to as a cooling stage. The refrigerant gas is also referred to as a working gas, and other suitable gases may be used although a helium gas is typically used. Thecompressor 12 and thecold head 14 configure a refrigeration cycle of thecryocooler 10, and thereby the low-temperature section 14 b is cooled to a desired cryogenic temperature. The low-temperature section 14 b can cool an object to be cooled such as a superconducting magnet. - Although the
cryocooler 10 is, for example, a single-stage or two-stage Gifford-McMahon (GM) cryocooler, thecryocooler 10 may be a pulse tube cryocooler, a Stirling cryocooler, or other types of cryocoolers. Although thecold head 14 has a different configuration depending on the type of thecryocooler 10, thecompressor 12 can use the configuration described below regardless of the type of thecryocooler 10. - In general, both a pressure of a refrigerant gas supplied from the
compressor 12 to thecold head 14 and a pressure of a refrigerant gas collected from thecold head 14 to thecompressor 12 are considerably higher than the atmospheric pressure, and can be called a first high pressure and a second high pressure, respectively. For convenience of description, the first high pressure and the second high pressure are also simply called a high pressure and a low pressure, respectively. Typically, the high pressure is, for example, 2 to 3 MPa. The low pressure is, for example, 0.5 to 1.5 MPa and is, for example, approximately 0.8 MPa. - The
compressor 12 includes a compressormain body 16, arefrigerant gas line 18, anoil circulation line 20, and acompressor cooling system 22. InFIG. 2 , in order to facilitate understanding, therefrigerant gas line 18 is shown by a solid line, and theoil circulation line 20 is shown by a broken line. Although details will be described later, thecompressor cooling system 22 is configured to include a liquid-cooledheat exchanger 24 and an air-cooledheat exchanger 26 and to cool therefrigerant gas line 18 and theoil circulation line 20. In addition, thecompressor 12 includes acompressor casing 28 that accommodates each of components of thecompressor 12, such as the compressormain body 16, therefrigerant gas line 18, theoil circulation line 20, and thecompressor cooling system 22. - The compressor
main body 16 is configured to internally compress a refrigerant gas sucked from a suction port thereof and to discharge the refrigerant gas from a discharge port. An oil is used in the compressormain body 16 for the sake of cooling and lubrication, and the sucked refrigerant gas is directly exposed to the oil in the compressormain body 16. Accordingly, the refrigerant gas is delivered from the discharge port in a state where the oil is slightly mixed. - The compressor
main body 16 may be, for example, a scroll type pump, a rotary type pump, or other pumps that pressurize a refrigerant gas. The compressormain body 16 may be configured to discharge the refrigerant gas at a fixed and constant flow rate. Alternatively, the compressormain body 16 may be configured to have a variable flow rate of the refrigerant gas to be discharged. The compressormain body 16 is called a compression capsule in some cases. - The
refrigerant gas line 18 includes adischarge port 30, asuction port 31, adischarge flow path 32, and asuction flow path 33. Thedischarge port 30 is an outlet of a refrigerant gas that is provided in thecompressor casing 28 in order to deliver the refrigerant gas, which is pressurized to a high pressure by the compressormain body 16, from thecompressor 12, and thesuction port 31 is an inlet of the refrigerant gas that is provided in thecompressor casing 28 in order for thecompressor 12 to receive the low-pressure refrigerant gas. Thecompressor casing 28 accommodates thedischarge flow path 32 and thesuction flow path 33. The discharge port of the compressormain body 16 is connected to thedischarge port 30 by thedischarge flow path 32, and thesuction port 31 is connected to the suction port of the compressormain body 16 by thesuction flow path 33. - The liquid-cooled
heat exchanger 24 and the air-cooledheat exchanger 26 that configure thecompressor cooling system 22 are provided at thedischarge flow path 32. In addition, anoil separator 34 and anadsorber 35 are provided downstream of thecompressor cooling system 22 at thedischarge flow path 32. - The
oil separator 34 is provided in order to separate an oil, which is mixed in a refrigerant gas as passing through the compressormain body 16, out from the refrigerant gas. Theadsorber 35 is provided in order to remove, for example, a vaporized oil and other contaminants remaining in the refrigerant gas from the refrigerant gas through adsorption. Theoil separator 34 and theadsorber 35 are connected in series. In thedischarge flow path 32, theoil separator 34 is disposed on a compressormain body 16 side, and theadsorber 35 is disposed on adischarge port 30 side. - An
oil return line 21 that connects theoil separator 34 to the compressormain body 16 is provided. An oil collected by theoil separator 34 can return to the compressormain body 16 through theoil return line 21. In the middle of theoil return line 21, a filter that removes dust included in the oil separated out by theoil separator 34 and an orifice that controls the amount of the oil returning to the compressormain body 16 may be provided. - On the other hand, a
storage tank 36 is provided at thesuction flow path 33. Thestorage tank 36 is provided as a volume for removing pulsation included in a low-pressure refrigerant gas returning from thecold head 14 to thecompressor 12. - In addition, a refrigerant
gas bypass valve 38 that connects thedischarge flow path 32 to thesuction flow path 33 to bypass the compressormain body 16 is provided at therefrigerant gas line 18. For example, the refrigerantgas bypass valve 38 branches off from thedischarge flow path 32 between theoil separator 34 and theadsorber 35 and is connected to thesuction flow path 33 between the compressormain body 16 and thestorage tank 36. The refrigerantgas bypass valve 38 is provided in order to control a flow rate of a refrigerant gas and/or in order to equalize thedischarge flow path 32 and thesuction flow path 33 when thecompressor 12 is stopped. - The
refrigerant gas line 18 of thecompressor 12 is connected to thecold head 14. A high-pressure port 40 and a low-pressure port 41 are provided in theroom temperature section 14 a of thecold head 14. The high-pressure port 40 is connected to thedischarge port 30 by a high-pressure pipe 42, and the low-pressure port 41 is connected to thesuction port 31 by a low-pressure pipe 43. - The
oil circulation line 20 connects an oil outlet to an oil inlet of the compressormain body 16 via the compressor cooling system 22 (that is, the liquid-cooledheat exchanger 24 and the air-cooled heat exchanger 26). Accordingly, an oil flowing out from the compressormain body 16 can be cooled by thecompressor cooling system 22 and flow into the compressormain body 16 again. - In the embodiment, the
oil circulation line 20 branches into a plurality of (two in the example) oil flow paths at thecompressor cooling system 22 as will be described later. The branched oil flow paths merge between thecompressor cooling system 22 and the oil inlet of the compressormain body 16 again. - An orifice that controls a flow rate of an oil flowing inside may be provided at the
oil circulation line 20. In addition, a filter that removes dust included in the oil may be provided at theoil circulation line 20. Such an orifice and such a filter may be provided, for example, on a downstream side of theoil circulation line 20, that is, between thecompressor cooling system 22 and the oil inlet of the compressormain body 16. - As described above, the
compressor cooling system 22 includes the liquid-cooledheat exchanger 24 and the air-cooledheat exchanger 26. The liquid-cooledheat exchanger 24 and the air-cooledheat exchanger 26 are connected in series, and the liquid-cooledheat exchanger 24 is provided upstream of the air-cooledheat exchanger 26. Accordingly, an oil heated by compression heat generated with compression of a refrigerant gas in the compressormain body 16 and a high-pressure refrigerant gas initially flow from the compressormain body 16 into the liquid-cooledheat exchanger 24 to be cooled and then flow into the air-cooledheat exchanger 26. - In the embodiment, the liquid-cooled
heat exchanger 24 is mounted on thecompressor 12 as a main cooling device of thecompressor 12, and the air-cooledheat exchanger 26 is mounted on thecompressor 12 as a backup cooling device of thecompressor 12. Accordingly, the liquid-cooledheat exchanger 24 operates at all times during an operation of thecompressor 12, and the air-cooledheat exchanger 26 does not operate when the liquid-cooledheat exchanger 24 operates normally, but may operate when the liquid-cooledheat exchanger 24 does not operate due to a failure or when a cooling capacity thereof has decreased. Thus, the air-cooledheat exchanger 26 may be configured to switch on or off based on an output of a sensor provided at thecompressor 12, such as a temperature sensor for an oil or a refrigerant gas. - The liquid-cooled
heat exchanger 24 includes afirst portion 24 a that cools a refrigerant gas through heat exchange between the refrigerant gas and a coolant and asecond portion 24 b that cools an oil through heat exchange between the oil and the coolant. Thefirst portion 24 a is disposed between the compressormain body 16 and theoil separator 34 at thedischarge flow path 32, more specifically, between the discharge port of the compressormain body 16 and the air-cooledheat exchanger 26 and cools the refrigerant gas flowing in thedischarge flow path 32. Thesecond portion 24 b is disposed between the oil outlet of the compressormain body 16 and the air-cooledheat exchanger 26 at theoil circulation line 20 and cools the oil flowing in theoil circulation line 20. - Although water (for example, tap water and industrial water) is typically used as a coolant, other suitable coolants may be used. A supply side of the
coolant line 106 is connected to acoolant inlet port 60 of thecompressor 12, and a collection side of thecoolant line 106 is connected to acoolant outlet port 61 of thecompressor 12. Accordingly, the coolant is supplied from the supply side of thecoolant line 106 to thecompressor 12 through thecoolant inlet port 60. The coolant from thecoolant inlet port 60 is supplied to thefirst portion 24 a and thesecond portion 24 b of the liquid-cooledheat exchanger 24 in order to cool a refrigerant gas and an oil. The coolant used in cooling at the liquid-cooledheat exchanger 24 is discharged from thecompressor 12 to the collection side of thecoolant line 106 through thecoolant outlet port 61. In this manner, compression heat generated by the compressormain body 16 is removed to the outside of thecompressor 12 together with the coolant. The coolant may be cooled by a coolant circulation device (for example, the cooler 110 shown inFIG. 1 ), such as a known water chiller, and be supplied to thecompressor 12 through thecoolant line 106 again. - In addition, the air-cooled
heat exchanger 26 includes a coolingfan 50, afirst oil line 46 that is disposed to be forcibly cooled by the coolingfan 50, and asecond oil line 48 that bypasses thefirst oil line 46 and that is disposed to be forcibly cooled by the coolingfan 50. - The
first oil line 46 and thesecond oil line 48 are a portion of theoil circulation line 20 disposed in the air-cooledheat exchanger 26. Thesecond oil line 48 branches off from theoil circulation line 20 upstream of the air-cooledheat exchanger 26, that is, between the liquid-cooledheat exchanger 24 and the air-cooledheat exchanger 26 and merges with thefirst oil line 46 again downstream of the air-cooledheat exchanger 26, that is, between the air-cooledheat exchanger 26 and the oil inlet of the compressormain body 16. - As an exemplary configuration, the cooling
fan 50 is provided in thecompressor casing 28 to exhaust air from the air-cooledheat exchanger 26 to the outside as the coolingfan 50 operates. Twoair intakes 52 are provided at a portion of thecompressor casing 28 surrounding the air-cooledheat exchanger 26, and air is taken into the air-cooledheat exchanger 26 through the air intakes 52 from the outside as the coolingfan 50 operates. An airflow that blows from oneair intake 52 into the air-cooledheat exchanger 26 is used in forced cooling of therefrigerant gas line 18 and thefirst oil line 46, and another airflow that blows from theother air intake 52 into the air-cooledheat exchanger 26 is used in forced cooling of thesecond oil line 48. InFIG. 2 , for the sake of understanding, the airflows are schematically shown by thick arrows. - The cooling
fan 50 of the air-cooledheat exchanger 26 may be configured such that the cooling fan may generate an airflow in a direction opposite to the example described above and blow air from the outside into the air-cooledheat exchanger 26. The coolingfan 50 may be configured to blow air to therefrigerant gas line 18, thefirst oil line 46, and thesecond oil line 48. - During an operation of the
cryocooler 10, a refrigerant gas collected from thecold head 14 to thecompressor 12 flows from the low-pressure port 41 into thesuction port 31 of thecompressor 12 through the low-pressure pipe 43. The refrigerant gas is collected to the suction port of the compressormain body 16 via thestorage tank 36 on thesuction flow path 33. The refrigerant gas is compressed and pressurized by the compressormain body 16. The refrigerant gas delivered from the discharge port of the compressormain body 16 is cooled by the liquid-cooledheat exchanger 24 and the air-cooledheat exchanger 26 and exits thecompressor 12 from thedischarge port 30 via theoil separator 34 and theadsorber 35. The refrigerant gas is supplied into thecold head 14 via the high-pressure pipe 42 and the high-pressure port 40. - An oil flowing out from the oil outlet of the compressor
main body 16 flows into the liquid-cooledheat exchanger 24 through theoil circulation line 20 and is cooled through heat exchange between the oil and a coolant at the liquid-cooledheat exchanger 24. The cooled oil flows from the liquid-cooledheat exchanger 24 into the air-cooledheat exchanger 26. The oil branches off and flows to thefirst oil line 46 and thesecond oil line 48 in the air-cooledheat exchanger 26. In a case where the coolingfan 50 operates, the oil is cooled with air when flowing in thefirst oil line 46 and thesecond oil line 48. The oil flowing out from the air-cooledheat exchanger 26 returns to the oil inlet of the compressormain body 16 through theoil circulation line 20. - In the embodiment, the
compressor 12 includes a coolingcontroller 70 that is configured to acquire a supply temperature of a coolant supplied to the liquid-cooledheat exchanger 24 and to control a flow rate of the coolant of the liquid-cooledheat exchanger 24 based on the acquired supply temperature of the coolant. The coolingcontroller 70 is configured to compare the acquired supply temperature of the coolant with a temperature threshold value and to control the flow rate of the coolant of the liquid-cooledheat exchanger 24 in a case where the supply temperature exceeds the temperature threshold value. - The cooling
controller 70 includes atemperature sensor 72 that measures a supply temperature of a coolant supplied to the liquid-cooledheat exchanger 24. Thetemperature sensor 72 is provided on the supply side of thecoolant line 106 and in this example, between thecoolant inlet port 60 and the liquid-cooledheat exchanger 24 in thecompressor 12. Thetemperature sensor 72 may be provided at thecoolant inlet port 60. The temperature sensor may be, for example, a thermistor. - In addition, the cooling
controller 70 includes acoolant bypass valve 74 that is connected in parallel with the liquid-cooledheat exchanger 24 and avalve controller 76 that is configured to open thecoolant bypass valve 74 or to increase an opening degree thereof in a case where a supply temperature of a coolant exceeds the temperature threshold value. - The cooling
controller 70 and/or thevalve controller 76 is realized by an element or a circuit including a CPU and a memory of a computer as a hardware configuration and is realized by a computer program as a software configuration, but is shown in the drawings as appropriate as a functional block realized in cooperation therewith. It is clear for those skilled in the art that the functional blocks can be realized in various manners in combination with hardware and software. - The
valve controller 76 may be a valve drive circuit (valve driver) or may be incorporated in thecoolant bypass valve 74 or other valves. Alternatively, thevalve controller 76 may be provided outside the valve or may be connected to the valve. - The cooling
controller 70 operates, for example, as follows. First, a supply temperature of a coolant supplied to the liquid-cooledheat exchanger 24 is acquired. The coolant temperature is measured by thetemperature sensor 72. A signal indicating the measurement temperature is output from thetemperature sensor 72 and is transmitted to thevalve controller 76. Thevalve controller 76 receives the measurement temperature signal from thetemperature sensor 72. In this manner, thevalve controller 76 can acquire the supply temperature of the coolant supplied to the liquid-cooledheat exchanger 24. - The
valve controller 76 controls a flow rate of a coolant of the liquid-cooledheat exchanger 24 based on an acquired supply temperature of the coolant. Specifically, for example, thevalve controller 76 compares the acquired supply temperature of the coolant with the temperature threshold value. Thecoolant bypass valve 74 may be an on/off valve. In this case, thevalve controller 76 opens and closes thecoolant bypass valve 74 based on the comparison result. Alternatively, thecoolant bypass valve 74 may be a flow rate control valve. In this case, thevalve controller 76 may open and close thecoolant bypass valve 74 based on the comparison result or adjust an opening degree thereof. - The temperature threshold value may be set based on an upper limit temperature (for example, approximately 30° C.) on the specification of a coolant temperature at which the cooler 110 supplies a coolant and may be equal to, for example, the upper limit temperature. It is possible to set the temperature threshold value as appropriate based on empirical knowledge of a designer or experiments and simulations by the designer. The temperature threshold value may be set in advance and be stored in the
valve controller 76. - When a supply temperature of a coolant falls below the temperature threshold value, the
valve controller 76 closes thecoolant bypass valve 74. In this case, the coolant supplied from thecoolant line 106 flows into the liquid-cooledheat exchanger 24. Accordingly, the coolant is used in cooling of a refrigerant gas and an oil at the liquid-cooledheat exchanger 24. - On the other hand, when a supply temperature of a coolant exceeds the temperature threshold value, the
valve controller 76 opens thecoolant bypass valve 74. In this case, the coolant supplied from thecoolant line 106 can flow to both thecoolant bypass valve 74 and the liquid-cooledheat exchanger 24. However, since a flow path resistance of the liquid-cooledheat exchanger 24 is generally high, in reality, most or substantially all of the coolant flows to thecoolant bypass valve 74 instead of the liquid-cooledheat exchanger 24. - In a case where the
coolant bypass valve 74 is a type of which an opening degree can be controlled, thevalve controller 76 may increase the opening degree of thecoolant bypass valve 74 when a supply temperature of a coolant exceeds the temperature threshold value. When the supply temperature of the coolant falls below the temperature threshold value, thevalve controller 76 may decrease the opening degree of thecoolant bypass valve 74. Even in this manner, when a temperature of the coolant supplied to the liquid-cooledheat exchanger 24 is high, cooling of the liquid-cooledheat exchanger 24 can be limited. In addition, when the coolant temperature decreases, the limitation can be alleviated or lifted. - As described above, the cooling capacity of the cooler 110 is insufficient due to an external factor such as an environment temperature or other factors, and a situation in which a rise in a supply temperature of a coolant from the cooler 110 to the
compressor 12 can be caused. According to the embodiment, the coolingcontroller 70 can limit a flow rate of the coolant of the liquid-cooledheat exchanger 24 using thecoolant bypass valve 74. The coolant bypasses the liquid-cooledheat exchanger 24 through thecoolant bypass valve 74. As a result, the coolant is mostly (or entirely) not supplied to the liquid-cooledheat exchanger 24, and cooling action of the liquid-cooledheat exchanger 24 is limited or practically eliminated. Thecompressor 12 can reduce the amount of heat dissipation to the cooler 110 and that is, can reduce a load on thecooler 110. - The remaining capacity of the cooler 110 generated in this manner can be used in cooling of another device 102 in the
cryogenic device 100 that requires heat dissipation. In this manner, it is possible to respond to a cooling capacity insufficiency and a problem attributable thereto, which can occur in the cooler 110, and to continue operation of thecryogenic device 100. - Further, the cooling
controller 70 may be configured to operate the air-cooledheat exchanger 26 in a case where a supply temperature of a coolant supplied to the liquid-cooledheat exchanger 24 exceeds the temperature threshold value. In this manner, in spite of supply limitation of the coolant to the liquid-cooledheat exchanger 24 described above, thecompressor 12 can be maintained cool using the air-cooledheat exchanger 26 or a combination of the liquid-cooledheat exchanger 24 and the air-cooledheat exchanger 26. - In this case, for example, the
valve controller 76 may be configured to control not only thecoolant bypass valve 74 but also the coolingfan 50. Thevalve controller 76 may operate the coolingfan 50 in an interlocking manner with an operation of thecoolant bypass valve 74 described above based on a supply temperature of a coolant. - That is, when a supply temperature of a coolant exceeds the temperature threshold value, the
valve controller 76 opens thecoolant bypass valve 74 and operates the air-cooled heat exchanger 26 (turns the coolingfan 50 on). On the other hand, when the supply temperature of the coolant falls below the temperature threshold value, thevalve controller 76 closes thecoolant bypass valve 74 and does not operate the air-cooled heat exchanger 26 (turns the coolingfan 50 off). The temperature threshold value may be the same value as the temperature threshold value that is used in order to open and close thecoolant bypass valve 74 and that is described above. - By operating the air-cooled
heat exchanger 26, heat generated by thecompressor 12 is released to the periphery of thecompressor 12 together with an airflow of the air-cooledheat exchanger 26. In some cases, this causes an excessive rise in an ambient temperature, and there is a concern that peripheral devices are adversely affected. - In order to respond to this, the cooling
controller 70 may be configured to acquire an ambient temperature and to stop the air-cooledheat exchanger 26 based on the acquired ambient temperature. In addition thereto or instead thereof, the coolingcontroller 70 may be configured to acquire the ambient temperature and to release limitation of a flow rate of a coolant of the liquid-cooledheat exchanger 24 based on the acquired ambient temperature. - In order to acquire an ambient temperature, the cooling
controller 70 may include anambient temperature sensor 54 that measures the ambient temperature. Theambient temperature sensor 54 may be disposed, for example, at thecompressor casing 28 in the vicinity of the air-cooledheat exchanger 26. Theambient temperature sensor 54 may be provided at the coolingfan 50. - For example, the cooling controller 70 (for example, the valve controller 76) acquires an ambient temperature measured by the
ambient temperature sensor 54 and compares the ambient temperature with a predetermined ambient temperature threshold value. When the ambient temperature falls below the ambient temperature threshold value, the coolingcontroller 70 operates the air-cooledheat exchanger 26. In addition thereto or instead thereof, the coolingcontroller 70 limits a flow rate of a coolant of the liquid-cooledheat exchanger 24 as described above (for example, opens the coolant bypass valve 74). On the other hand, when the ambient temperature exceeds the ambient temperature threshold value, the coolingcontroller 70 does not operate the air-cooledheat exchanger 26. In addition thereto or instead thereof, the coolingcontroller 70 releases the limitation of the flow rate of the coolant of the liquid-cooled heat exchanger 24 (for example, closes the coolant bypass valve 74). -
FIG. 3 is a diagram schematically showing another example of the coolingcontroller 70 according to the embodiment. In addition to thetemperature sensor 72 and thevalve controller 76 that are described above, the coolingcontroller 70 may include acontrol valve 75 that is connected to the liquid-cooledheat exchanger 24 in series. Thecontrol valve 75 may be an on/off valve. Alternatively, thecontrol valve 75 may be a flow rate control valve. The coolingcontroller 70 may be configured to open and close thecontrol valve 75 or to adjust an opening degree thereof based on a supply temperature of a coolant acquired from thetemperature sensor 72 and thereby to control a flow rate of the coolant of the liquid-cooledheat exchanger 24. - For example, the
valve controller 76 compares a supply temperature of a coolant acquired from thetemperature sensor 72 with the temperature threshold value. When the supply temperature of the coolant falls below the temperature threshold value, thevalve controller 76 opens thecontrol valve 75. In this case, the coolant supplied from thecoolant line 106 flows into the liquid-cooledheat exchanger 24. Accordingly, the coolant is used in cooling of a refrigerant gas and an oil at the liquid-cooledheat exchanger 24. On the other hand, when the supply temperature of the coolant exceeds the temperature threshold value, thevalve controller 76 closes thecontrol valve 75. In this case, the coolant supplied from thecoolant line 106 is shut off. Accordingly, the coolant is not used in cooling at the liquid-cooledheat exchanger 24. - Even in this manner, the
compressor 12 can reduce the amount of heat dissipation to the cooler 110 as a countermeasure to a temperature rise of a coolant and reduce a load on thecooler 110. - In a case where the
control valve 75 is a type of which an opening degree can be controlled, thevalve controller 76 may decrease the opening degree of thecontrol valve 75 when a supply temperature of a coolant exceeds the temperature threshold value. When the supply temperature of the coolant falls below the temperature threshold value, thevalve controller 76 may increase the opening degree of thecontrol valve 75. Even in this manner, when a temperature of the coolant supplied to the liquid-cooledheat exchanger 24 is high, cooling of the liquid-cooledheat exchanger 24 can be limited. In addition, when the coolant temperature decreases, the limitation can be alleviated or lifted. - In addition, as shown by a broken line in
FIG. 3 , thecoolant bypass valve 74 described above may be used in combination with thecontrol valve 75. The coolingcontroller 70 may be configured to interlock thecoolant bypass valve 74 and thecontrol valve 75 based on a supply temperature of a coolant. For example, thevalve controller 76 may control both thecoolant bypass valve 74 and thecontrol valve 75. Thevalve controller 76 may control thecontrol valve 75 in an interlocking manner with an operation of thecoolant bypass valve 74 described above based on the supply temperature of the coolant. That is, when the supply temperature of the coolant exceeds the temperature threshold value, thevalve controller 76 may open thecoolant bypass valve 74 or close thecontrol valve 75. On the other hand, when the supply temperature of the coolant falls below the temperature threshold value, thevalve controller 76 may close thecoolant bypass valve 74 or open thecontrol valve 75. -
FIG. 4 is a diagram schematically showing still another example of the coolingcontroller 70 according to the embodiment. The coolingcontroller 70 includes asecond temperature sensor 73 and aflow rate sensor 78 on a collection side, in addition to thefirst temperature sensor 72 on a supply side. Thesecond temperature sensor 73 measures a discharge temperature of a coolant discharged from the liquid-cooledheat exchanger 24. Thesecond temperature sensor 73 may be provided between thecoolant outlet port 61 and the liquid-cooledheat exchanger 24 or at thecoolant outlet port 61. Theflow rate sensor 78 measures a flow rate of the coolant of the liquid-cooledheat exchanger 24. Theflow rate sensor 78 is provided on the supply side of thecoolant line 106 and in this example, between thefirst temperature sensor 72 and thecontrol valve 75. - As will be described below, the cooling
controller 70 may be configured to acquire a supply temperature of a coolant supplied to the liquid-cooledheat exchanger 24, a discharge temperature of the coolant discharged from the liquid-cooledheat exchanger 24, and a flow rate of the coolant of the liquid-cooledheat exchanger 24, to calculate the amount of heat dissipation to the liquid-cooledheat exchanger 24 based on the acquired supply temperature, the acquired discharge temperature, and the acquired flow rate of the coolant, and to limit the flow rate of the coolant of the liquid-cooledheat exchanger 24 such that the calculated amount of heat dissipation is equal to or smaller than an allowable amount of heat dissipation. - For example, the
valve controller 76 first acquires a supply temperature of a coolant supplied to the liquid-cooledheat exchanger 24 from thefirst temperature sensor 72, acquires a discharge temperature of the coolant discharged from the liquid-cooledheat exchanger 24 from thesecond temperature sensor 73, and acquires a flow rate of the coolant of the liquid-cooledheat exchanger 24 from theflow rate sensor 78. - Next, the
valve controller 76 calculates the amount of heat dissipation to the liquid-cooledheat exchanger 24 based on the acquired supply temperature, the acquired discharge temperature, and the acquired coolant flow rate. The amount of heat dissipation from thecompressor 12 to the liquid-cooledheat exchanger 24 can be calculated, through a known method, from a temperature difference between the outlet and the inlet of the liquid-cooledheat exchanger 24 and the flow rate of the coolant flowing in the liquid-cooledheat exchanger 24. - Then, the
valve controller 76 limits the flow rate of the coolant of the liquid-cooledheat exchanger 24 such that the calculated amount of heat dissipation is equal to or smaller than the allowable amount of heat dissipation. The allowable amount of heat dissipation is an amount of heat dissipation that is allowed to be dissipated from thecompressor 12 to the cooler 110 by the liquid-cooledheat exchanger 24, and for example, may be a value correlated with the supply temperature of the coolant or may be a constant value. It is possible to set the allowable amount of heat dissipation as appropriate based on empirical knowledge of the designer or experiments and simulations by the designer. - The
valve controller 76 compares the calculated amount of heat dissipation with the allowable amount of heat dissipation. When the calculated amount of heat dissipation falls below the allowable amount of heat dissipation, thevalve controller 76 opens thecontrol valve 75. In this case, the coolant supplied from thecoolant line 106 flows into the liquid-cooledheat exchanger 24. Accordingly, the coolant is used in cooling of a refrigerant gas and an oil at the liquid-cooledheat exchanger 24. On the other hand, when the calculated amount of heat dissipation exceeds the allowable amount of heat dissipation, thevalve controller 76 closes thecontrol valve 75. In this case, the coolant supplied from thecoolant line 106 is shut off. Accordingly, the coolant is not used in cooling at the liquid-cooledheat exchanger 24. - Even in this manner, the
compressor 12 can reduce the amount of heat dissipation to the cooler 110 and reduce a load on thecooler 110. - In a case where the
control valve 75 is a type of which an opening degree can be controlled, thevalve controller 76 may decrease the opening degree of thecontrol valve 75 when the calculated amount of heat dissipation exceeds the allowable amount of heat dissipation. When the calculated amount of heat dissipation falls below the allowable amount of heat dissipation, thevalve controller 76 may increase the opening degree of thecontrol valve 75. Even in this manner, when the amount of heat dissipation from thecompressor 12 to the liquid-cooledheat exchanger 24 is large, cooling by the liquid-cooledheat exchanger 24 can be limited. In addition, when the amount of heat dissipation decreases, the limitation can be alleviated or lifted. - In addition, also in the embodiment of
FIG. 4 , thecoolant bypass valve 74 described above may be used in combination with thecontrol valve 75 as in the embodiment ofFIG. 3 . The coolingcontroller 70 may be configured to interlock thecoolant bypass valve 74 and thecontrol valve 75 based on the calculated amount of heat dissipation. For example, thevalve controller 76 may control both thecoolant bypass valve 74 and thecontrol valve 75. Thevalve controller 76 may control thecoolant bypass valve 74 in an interlocking manner with an operation of thecontrol valve 75 described above based on the calculated amount of heat dissipation. That is, when the calculated amount of heat dissipation exceeds the allowable amount of heat dissipation, thevalve controller 76 may open thecoolant bypass valve 74 or close thecontrol valve 75. On the other hand, when the calculated amount of heat dissipation falls below the allowable amount of heat dissipation, thevalve controller 76 may close thecoolant bypass valve 74 or open thecontrol valve 75. -
FIG. 5 is a diagram schematically showing still another example of the coolingcontroller 70 according to the embodiment. Thecompressor 12 includes acompressor motor 80 that has a variable operation frequency (that is, a rotation speed), and the compressormain body 16 is driven by thecompressor motor 80. Thecompressor motor 80 may be, for example, an electric motor or any other suitable type of motor. A discharge flow rate of the compressormain body 16 is increased by increasing the operation frequency of thecompressor motor 80. In this case, an exhaust heat amount of thecompressor 12 also increases. Conversely, the discharge flow rate of the compressormain body 16 is decreased by decreasing the operation frequency of thecompressor motor 80. In this case, the exhaust heat amount of thecompressor 12 also decreases. - The cooling
controller 70 includes aninverter 82 that controls an operation frequency of thecompressor motor 80. Thecompressor motor 80 and theinverter 82 are supplied with power from an external power source such as a commercial power source (three-phase alternating current power source). Theinverter 82 is configured to adjust a frequency of power input from the external power source and to output any frequency to thecompressor motor 80 under control by the coolingcontroller 70 as will be described later. The operation frequency of thecompressor motor 80 corresponds to an output frequency of theinverter 82 and can be adjusted within, for example, a range of 30 Hz to 100 Hz or a range of 40 Hz to 70 Hz. - The cooling
controller 70 is configured to acquire a supply temperature of a coolant supplied to the liquid-cooledheat exchanger 24 and to control an exhaust heat amount of thecompressor 12 based on the acquired supply temperature of the coolant. The coolingcontroller 70 is configured to compare the acquired supply temperature of the coolant with the temperature threshold value and to control an operation frequency of thecompressor motor 80 in a case where the supply temperature exceeds the temperature threshold value. - For example, the cooling
controller 70 compares a supply temperature of a coolant acquired from thetemperature sensor 72 with the temperature threshold value. When the supply temperature of the coolant falls below the temperature threshold value, the coolingcontroller 70 maintains an operation frequency of thecompressor motor 80. Alternatively, the coolingcontroller 70 allows an increase in the operation frequency of thecompressor motor 80. That is, an exhaust heat amount of thecompressor 12 is allowed to increase. - On the other hand, when a supply temperature of a coolant exceeds the temperature threshold value, the cooling
controller 70 decreases an operation frequency of thecompressor motor 80. A decreased amount of the operation frequency may be a constant value or may be determined depending on a difference between the supply temperature of the coolant and the temperature threshold value. In this case, an exhaust heat amount of thecompressor 12 can be decreased. - Even in this manner, the
compressor 12 can decrease the amount of heat generated by thecompressor 12 and can reduce a load on thecooler 110. - The embodiment described above, in which an operation frequency of the compressor motor is limited, may be used in combination with the embodiment which is described with reference to
FIGS. 1 to 4 and in which a flow rate of a coolant of the liquid-cooledheat exchanger 24 is limited. - The present invention has been described hereinbefore based on the examples. It is clear for those skilled in the art that the present invention is not limited to the embodiment, various design changes are possible, various modification examples are possible, and such modification examples are also within the scope of the present invention. Various characteristics described in relation to one embodiment are also applicable to other embodiments. A new embodiment generated through combination also has the effects of each of the combined embodiments.
- In the embodiment described above, the liquid-cooled
heat exchanger 24 and the air-cooledheat exchanger 26 are connected in series in thecompressor cooling system 22, and the liquid-cooledheat exchanger 24 is provided upstream of the air-cooledheat exchanger 26. However, thecompressor cooling system 22 can have other configurations. For example, the liquid-cooledheat exchanger 24 and the air-cooledheat exchanger 26 may be connected in series, and the air-cooledheat exchanger 26 may be provided upstream of the liquid-cooledheat exchanger 24. Alternatively, the liquid-cooledheat exchanger 24 and the air-cooledheat exchanger 26 may be connected in parallel. - In addition, the liquid-cooled
heat exchanger 24 may be configured to cool only one of a refrigerant gas and an oil. Alternatively, the liquid-cooledheat exchanger 24 may include a first liquid-cooled heat exchanger that cools the refrigerant gas and a second liquid-cooled heat exchanger that cools the oil. Similarly, the air-cooledheat exchanger 26 may be configured to cool only one of the refrigerant gas and the oil. Alternatively, the air-cooledheat exchanger 26 may include a first air-cooled heat exchanger that cools the refrigerant gas and a second air-cooled heat exchanger that cools the oil. - In the embodiment described above, the cooling
controller 70 is provided in thecompressor 12, that is, in thecompressor casing 28 of thecompressor 12. Instead thereof, the coolingcontroller 70 may be provided outside thecompressor 12. For example, the coolingcontroller 70 may be accommodated in a casing different from thecompressor casing 28 or may be disposed adjacent to or close to thecompressor casing 28 or away from thecompressor 12. - The
temperature sensor 72 for measuring a supply temperature of a coolant may be disposed at a location different from that of thecompressor 12. For example, thetemperature sensor 72 may be provided at the cooler 110. Alternatively, thetemperature sensor 72 may be provided at a coolant line to the other device 102. The coolingcontroller 70 may acquire the supply temperature of the coolant from thetemperature sensor 72 provided at the cooler 110 and/or the other device 102. - In order to alleviate or prevent a sudden change in a flow rate of a coolant of the liquid-cooled
heat exchanger 24 in response to an operation of thecoolant bypass valve 74 and/or thecontrol valve 75, the coolingcontroller 70 may include an orifice or a constant flow rate valve that is provided in series with thecoolant bypass valve 74 and/or in series with thecontrol valve 75. - Although the present invention has been described using specific phrases based on the embodiment, the embodiment merely shows one aspect of the principles and applications of the present invention, and many modification examples and changes in disposition are allowed without departing from the concept of the present invention specified in the claims.
- It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the invention. Additionally, the modifications are included in the scope of the invention.
Claims (9)
1. An oil-lubricated cryocooler compressor that compresses a refrigerant gas of a cryocooler, the cryocooler compressor comprising:
a liquid-cooled heat exchanger that cools the refrigerant gas and/or an oil through heat exchange with a coolant; and
a cooling controller that is configured to acquire a supply temperature of the coolant supplied to the liquid-cooled heat exchanger and to control a flow rate of the coolant of the liquid-cooled heat exchanger and/or an exhaust heat amount of the cryocooler compressor based on the acquired supply temperature of the coolant.
2. The cryocooler compressor according to claim 1 ,
wherein the cooling controller is configured to compare the acquired supply temperature of the coolant with a temperature threshold value and to limit the flow rate of the coolant of the liquid-cooled heat exchanger when the supply temperature exceeds the temperature threshold value.
3. The cryocooler compressor according to claim 2 ,
wherein the cooling controller comprises:
a control valve that is connected in series with the liquid-cooled heat exchanger, and
a valve controller that is configured to close the control valve or to decrease an opening degree of the control valve when the supply temperature of the coolant exceeds the temperature threshold value.
4. The cryocooler compressor according to claim 2 ,
wherein the cooling controller comprises:
a bypass valve that is connected in parallel with the liquid-cooled heat exchanger, and
a valve controller that is configured to open the bypass valve or to increase an opening degree of the bypass valve when the supply temperature of the coolant exceeds the temperature threshold value.
5. The cryocooler compressor according to claim 2 , further comprising:
an air-cooled heat exchanger that cools the refrigerant gas and/or the oil,
wherein the cooling controller is configured to operate the air-cooled heat exchanger when the supply temperature exceeds the temperature threshold value.
6. The cryocooler compressor according to claim 5 ,
wherein the cooling controller is configured to acquire an ambient temperature and to stop the air-cooled heat exchanger and/or to release a limitation of the flow rate of the coolant based on the acquired ambient temperature.
7. The cryocooler compressor according to claim 1 ,
wherein the cooling controller is configured to:
acquire a discharge temperature of the coolant discharged from the liquid-cooled heat exchanger and the flow rate of the coolant of the liquid-cooled heat exchanger,
calculate an amount of heat dissipation to the liquid-cooled heat exchanger based on the acquired supply temperature, the acquired discharge temperature, and the acquired flow rate of the coolant, and
limit the flow rate of the coolant of the liquid-cooled heat exchanger such that the calculated amount of heat dissipation is equal to or smaller than an allowable amount of heat dissipation.
8. The cryocooler compressor according to claim 1 , further comprising:
a compressor main body that compresses the refrigerant gas; and
a compressor motor that drives the compressor main body and that has a variable operation frequency,
wherein the cooling controller is configured to compare the acquired supply temperature of the coolant with a temperature threshold value and to limit the operation frequency of the compressor motor when the supply temperature exceeds the temperature threshold value.
9. An operation method of an oil-lubricated cryocooler compressor that compresses a refrigerant gas of a cryocooler, the cryocooler compressor including a liquid-cooled heat exchanger that cools the refrigerant gas and/or an oil through heat exchange with a coolant, the method comprising:
acquiring a supply temperature of the coolant supplied to the liquid-cooled heat exchanger; and
controlling a flow rate of the coolant of the liquid-cooled heat exchanger and/or an exhaust heat amount of the cryocooler compressor based on the acquired supply temperature of the coolant.
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JP2022-167002 | 2022-10-18 | ||
JP2022167002 | 2022-10-18 |
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US18/488,987 Pending US20240125548A1 (en) | 2022-10-18 | 2023-10-17 | Oil-lubricated cryocooler compressor and operation method thereof |
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US (1) | US20240125548A1 (en) |
EP (1) | EP4357696A1 (en) |
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2023
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