Cryocooler maintenance support device, cryocooler maintenance support method, and cryocooler

Abstract

To provide a technique for supporting determination of a maintenance plan of a cryogenic refrigerator.SOLUTION: The maintenance support device 70 for the cryocooler 10 includes the processor 72 configured to acquire the operation history-data D1 of the cryocooler 10 and to determine the maintenance plan of the cryocooler 10 based on the operation history-data D1. The operation history-data D1 of the cryocooler 10 includes the measured operation time of the cryocooler 10 and the operation state of the cryocooler 10 at the measured operation time. The processor 72 is configured to calculate the corrected operation time of the cryocooler 10 by increasing or decreasing the measured operation time based on the operation state of the cryocooler 10 in the measured operation time, and to determine the maintenance plan of the cryocooler 10 based on the corrected operation time of the cryocooler 10.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a cryogenic refrigerator maintenance support device, a cryogenic refrigerator maintenance support method, and a cryogenic refrigerator. [Background technology]

[0002] Cryogenic refrigerators, such as the Gifford-McMahon (GM) refrigerator, are used for various cryogenic cooling applications, such as superconducting equipment and liquefied gas storage. It is recommended that cryogenic refrigerators undergo regular maintenance at regular intervals specified by the manufacturer. The management of such maintenance schedules is typically left to the user of the cryogenic refrigerator. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-324010 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the appropriate maintenance intervals may differ depending on how the cryogenic refrigerator is used, so an efficient maintenance plan that is tailored to the actual operating conditions is desirable.

[0005] It is an exemplary object of an embodiment of the present invention to provide a technique for supporting the determination of a maintenance plan for a cryogenic refrigerator. [Means for solving the problem]

[0006] According to one aspect of the present invention, a cryogenic refrigerator maintenance support device includes a processor configured to acquire operation history data of a cryogenic refrigerator and determine a maintenance plan for the cryogenic refrigerator based on the operation history data. The operation history data of the cryogenic refrigerator includes measured operation times of the cryogenic refrigerator and operating states of the cryogenic refrigerator during the measured operation times. The processor is configured to calculate a corrected operation time of the cryogenic refrigerator by increasing or decreasing the measured operation time based on the operating states of the cryogenic refrigerator during the measured operation times, and to determine a maintenance plan for the cryogenic refrigerator based on the corrected operation time of the cryogenic refrigerator.

[0007] According to one aspect of the present invention, a cryogenic refrigerator maintenance support method includes acquiring a measured operating time of a cryogenic refrigerator and an operating state of the cryogenic refrigerator during the measured operating time, calculating a corrected operating time of the cryogenic refrigerator by increasing or decreasing the measured operating time based on the operating state of the cryogenic refrigerator during the measured operating time, and determining a maintenance plan for the cryogenic refrigerator based on the corrected operating time of the cryogenic refrigerator.

[0008] According to one aspect of the present invention, a cryogenic refrigerator includes a timer that measures an operating time of the cryogenic refrigerator, at least one sensor that measures an operating state of the cryogenic refrigerator, and a processor configured to acquire the measured operating time of the cryogenic refrigerator and the operating state of the cryogenic refrigerator at the measured operating time, and calculate a corrected operating time of the cryogenic refrigerator by increasing or decreasing the measured operating time based on the operating state of the cryogenic refrigerator at the measured operating time.

[0009] Any combination of the above components, and conversion of the present invention between methods, devices, systems, recording media, computer programs, etc. are also valid aspects of the present invention. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a technique for supporting the determination of a maintenance plan for a cryogenic refrigerator. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a diagram schematically illustrating a cryogenic refrigerator according to an embodiment. [Figure 2] 1 is a block diagram illustrating a maintenance support system for a cryogenic refrigerator according to an embodiment. [Figure 3] 3 is a flowchart showing a maintenance support method for a cryogenic refrigerator according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description and drawings, identical or equivalent components, parts, and processes are designated by the same reference numerals, and redundant explanations will be omitted as appropriate. The scale and shape of each part shown in the drawings are set for convenience to facilitate explanation, and should not be interpreted as limiting unless otherwise specified. The embodiments are merely examples and do not limit the scope of the present invention in any way. All features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0013] 1 is a diagram schematically illustrating a cryogenic refrigerator 10 according to an embodiment. The cryogenic refrigerator 10 includes a compressor 12 and a cold head 14.

[0014] The cryogenic refrigerator 10 is used to provide cryogenic cooling to an object or medium. For example, the cryogenic refrigerator 10 may be used as a cooling source for a superconducting magnet device. The superconducting magnet device is installed in a high-magnetic field device (not shown) as a magnetic field source for, for example, a single crystal pulling device, a nuclear magnetic resonance (NMR) system, a magnetic resonance imaging (MRI) system, an accelerator such as a cyclotron, a high-energy physics system such as a nuclear fusion system, or other high-magnetic field device, and can generate the high magnetic field required for the device.

[0015] The compressor 12 is configured to recover refrigerant gas from the cryogenic refrigerator 10 through the cold head 14, pressurize the recovered refrigerant gas, and then supply the refrigerant gas back to the cold head 14. The compressor 12 is also referred to as a compressor unit. The cold head 14 is also referred to as an expander and has a room-temperature section 14a and a low-temperature section 14b, also referred to as a cooling stage. The refrigerant gas, also referred to as a working gas, is typically helium gas, although other suitable gases may be used. The compressor 12 and the cold head 14 form the refrigeration cycle of the cryogenic refrigerator 10, thereby cooling the low-temperature section 14b to a desired cryogenic temperature. The low-temperature section 14b can cool an object to be cooled, such as a superconducting magnet.

[0016] Cryogenic refrigerator 10 is, by way of example, a single-stage or two-stage Gifford-McMahon (GM) refrigerator, but may also be a pulse tube refrigerator, a Stirling refrigerator, or other types of cryogenic refrigerator. While cold head 14 has a different configuration depending on the type of cryogenic refrigerator 10, compressor 12 may have the configuration described below regardless of the type of cryogenic refrigerator 10.

[0017] Generally, the pressure of the refrigerant gas supplied from the compressor 12 to the cold head 14 and the pressure of the refrigerant gas recovered from the cold head 14 to the compressor 12 are both significantly higher than atmospheric pressure and can be referred to as the first high pressure and the second high pressure, respectively. For ease of explanation, the first high pressure and the second high pressure are also simply referred to as the high pressure and the 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, e.g., approximately 0.8 MPa.

[0018] The compressor 12 is an oil-lubricated compressor for a cryogenic refrigerator, and includes a compressor main body 16, a refrigerant gas line 18, an oil circulation line 20, and a compressor cooling system 22. In FIG. 1 , for ease of understanding, the refrigerant gas line 18 is indicated by a solid line, and the oil circulation line 20 is indicated by a dashed line. As will be described in detail later, the compressor cooling system 22 includes a water-cooled heat exchanger 24 and an air-cooled heat exchanger 26, and is configured to cool the refrigerant gas line 18 and the oil circulation line 20. The compressor 12 also includes a compressor housing 28 that houses each of the components of the compressor 12, such as the compressor main body 16, the refrigerant gas line 18, the oil circulation line 20, and the compressor cooling system 22.

[0019] The compressor body 16 is configured to compress the refrigerant gas drawn in through its suction port and discharge it from its discharge port. The compressor body 16 uses oil for cooling and lubrication, and the drawn refrigerant gas is directly exposed to this oil inside the compressor body 16. Therefore, the refrigerant gas is discharged from the discharge port with a small amount of oil mixed in.

[0020] The compressor body 16 may be, for example, a scroll type, a rotary type, or any other pump that pressurizes the refrigerant gas. Therefore, the compressor body 16 may include a compressor motor 16a that drives the compressor body 16. The compressor body 16 may be configured to vary the flow rate of the refrigerant gas discharged, and the compressor motor 16a may be an electric motor that varies the operating frequency (i.e., rotation speed). The compressor body 16 may also be referred to as a compression capsule.

[0021] The refrigerant gas line 18 includes a discharge port 30, a suction port 31, a discharge passage 32, and a suction passage 33. The discharge port 30 is a refrigerant gas outlet provided in the compressor housing 28 for sending refrigerant gas pressurized to a high pressure by the compressor body 16 from the compressor 12, and the suction port 31 is a refrigerant gas inlet provided in the compressor housing 28 for receiving low-pressure refrigerant gas into the compressor 12. The discharge passage 32 and the suction passage 33 are housed in the compressor housing 28. The discharge port of the compressor body 16 is connected to the discharge port 30 by the discharge passage 32, and the suction port 31 is connected to the suction port of the compressor body 16 by the suction passage 33.

[0022] The refrigerant gas line 18 is connected to the cold head 14. A high-pressure port 40 and a low-pressure port 41 are provided in the room-temperature section 14a of the cold head 14. The high-pressure port 40 is connected to the discharge port 30 by a high-pressure pipe 42, and the low-pressure port 41 is connected to the suction port 31 by a low-pressure pipe 43.

[0023] A water-cooled heat exchanger 24 and an air-cooled heat exchanger 26, which constitute the compressor cooling system 22, are provided in a discharge flow path 32 within the compressor 12. In addition, an oil separator 34 and an advertiser 35 are provided in the discharge flow path 32 downstream of the compressor cooling system 22.

[0024] The oil separator 34 is provided to separate oil from the refrigerant gas that becomes mixed with the refrigerant gas as it passes through the compressor body 16. The advertiser 35 is provided to remove remaining contaminants in the refrigerant gas, such as vaporized oil, from the refrigerant gas by adsorption. The oil separator 34 and advertiser 35 are connected in series. In the discharge flow path 32, the oil separator 34 is located on the compressor body 16 side, and the advertiser 35 is located on the discharge port 30 side.

[0025] An oil return line 21 is provided to connect the oil separator 34 to the compressor body 16. The oil recovered in the oil separator 34 can be returned to the compressor body 16 through the oil return line 21. A filter for removing dust contained in the oil separated in the oil separator 34 and an orifice for controlling the amount of oil returned to the compressor body 16 may be provided midway along the oil return line 21.

[0026] On the other hand, a storage tank 36 is provided in the suction passage 33. The storage tank 36 is provided as a volume for removing pulsation contained in the low-pressure refrigerant gas returning from the cold head 14 to the compressor 12.

[0027] The refrigerant gas line 18 is also provided with a refrigerant gas bypass valve 38 that connects the discharge passage 32 to the suction passage 33 so as to bypass the compressor body 16. As an example, the refrigerant gas bypass valve 38 branches off from the discharge passage 32 between the oil separator 34 and the adsorber 35, and is connected to the suction passage 33 between the compressor body 16 and the storage tank 36. The refrigerant gas bypass valve 38 is provided for refrigerant gas flow rate control and / or for equalizing the pressures in the discharge passage 32 and the suction passage 33 when the compressor 12 is stopped.

[0028] The oil circulation line 20 connects the oil outlet of the compressor body 16 to the oil inlet so as to pass through a compressor cooling system 22 (i.e., a water-cooled heat exchanger 24 and an air-cooled heat exchanger 26). Thus, oil flowing out of the compressor body 16 can be cooled by the compressor cooling system 22 and then flow back into the compressor body 16. The oil circulation line 20 may be provided with an orifice that controls the amount of oil flowing therethrough. The oil circulation line 20 may also be provided with a filter that removes dust particles contained in the oil. Such an orifice and filter may be provided, for example, downstream of the oil circulation line 20, i.e., between the compressor cooling system 22 and the oil inlet of the compressor body 16.

[0029] As described above, the compressor cooling system 22 includes the water-cooled heat exchanger 24 and the air-cooled heat exchanger 26 that cool the compressor 12. In this embodiment, the water-cooled heat exchanger 24 and the air-cooled heat exchanger 26 are connected in series, and the water-cooled heat exchanger 24 is provided upstream of the air-cooled heat exchanger 26. Therefore, oil and high-pressure refrigerant gas heated by heat of compression generated as the refrigerant gas is compressed in the compressor body 16 first flow from the compressor body 16 into the water-cooled heat exchanger 24 to be cooled, and then flow into the air-cooled heat exchanger 26. The water-cooled heat exchanger 24 may be provided downstream of the air-cooled heat exchanger 26 or may be provided in parallel with the air-cooled heat exchanger 26.

[0030] The water-cooled heat exchanger 24 includes a first portion 24a that cools the refrigerant gas through heat exchange between the refrigerant gas and the cooling water, and a second portion 24b that cools the oil through heat exchange between the oil and the cooling water. The first portion 24a is disposed in the discharge flow path 32 between the compressor body 16 and the oil separator 34, more specifically, between the discharge port of the compressor body 16 and the air-cooled heat exchanger 26, and cools the refrigerant gas flowing through the discharge flow path 32. The second portion 24b is disposed in the oil circulation line 20 between the oil outlet of the compressor body 16 and the air-cooled heat exchanger 26, and cools the oil flowing through the oil circulation line 20.

[0031] The air-cooled heat exchanger 26 includes a cooling fan 26a that forcibly cools the refrigerant gas line 18 and the oil circulation line 20 with airflow. In this embodiment, the air-cooled heat exchanger 26 is provided downstream of the water-cooled heat exchanger 24 as described above. Therefore, the cooling fan 26a is installed in the compressor housing 28 so as to apply airflow to the portion of the refrigerant gas line 18 between the first portion 24a of the water-cooled heat exchanger 24 and the oil separator 34, and to the portion of the oil circulation line 20 between the second portion 24b of the water-cooled heat exchanger 24 and the oil inlet of the compressor main body 16. The cooling fan 26a may be configured to take in air from outside the compressor housing 28 and blow the air onto the refrigerant gas line 18 and the oil circulation line 20, thereby cooling them. Alternatively, the cooling fan 26a may be configured to cool the refrigerant gas line 18 and the oil circulation line 20 by sucking air around them out of the compressor housing 28.

[0032] During operation of the cryogenic refrigerator 10, refrigerant gas is supplied from the compressor 12 to the cold head 14, and a refrigeration cycle (e.g., a GM cycle) is formed by periodic volume fluctuations in the expansion space of the refrigerant gas in the cold head 14 and synchronized pressure fluctuations of the refrigerant gas in the expansion space, thereby cooling the low-temperature section 14b of the cold head 14 to a desired cryogenic temperature. If the cold head 14 is, for example, a two-stage system, the first cooling stage is cooled to a first cooling temperature in the range of, for example, about 30 K to about 80 K, and the second cooling stage is cooled to a second cooling temperature lower than the first cooling temperature, for example, 1 K to 20 K. The second cooling temperature may be the liquid helium temperature of about 4.2 K or a temperature lower than that.

[0033] Refrigerant gas recovered from the cold head 14 to the compressor 12 flows from the low-pressure port 41 through the low-pressure piping 43 into the suction port 31 of the compressor 12. The refrigerant gas passes through the storage tank 36 on the suction passage 33 and is recovered to the suction port of the compressor body 16. The refrigerant gas is compressed and pressurized by the compressor body 16. At this time, the refrigerant gas is heated by the heat of compression. The refrigerant gas discharged from the discharge port of the compressor body 16 is cooled by the water-cooled heat exchanger 24 and the air-cooled heat exchanger 26, passes through the oil separator 34 and the adsorber 35, and leaves the compressor 12 from the discharge port 30. The refrigerant gas is supplied to the inside of the cold head 14 through the high-pressure piping 42 and the high-pressure port 40.

[0034] The oil flowing out from the oil outlet of the compressor body 16 flows through the oil circulation line 20 into the water-cooled heat exchanger 24, where it is cooled by heat exchange between the oil and cooling water. The cooled oil flows from the water-cooled heat exchanger 24 into the air-cooled heat exchanger 26. When the cooling fan 26a is operating, the oil is cooled by air. The oil flowing out from the air-cooled heat exchanger 26 is returned to the oil inlet of the compressor body 16 through the oil circulation line 20.

[0035] The compressor 12 may include at least one temperature sensor 50 that measures the temperature of the compressor 12. As an example, the temperature sensor 50 may include an oil temperature sensor that measures the oil temperature in the oil circulation line 20, as shown in the figure. This oil temperature sensor may be disposed, for example, downstream of the water-cooled heat exchanger 24, more specifically, between the second portion 24b of the water-cooled heat exchanger 24 and the air-cooled heat exchanger 26, in which case it can measure the temperature of the oil cooled by the water-cooled heat exchanger 24. The temperature sensor 50 may be any known temperature sensor, such as a thermistor.

[0036] Additionally or instead of this, another oil temperature sensor may be provided as the temperature sensor 50. For example, the other oil temperature sensor may be disposed upstream of the water-cooled heat exchanger 24 in the oil circulation line 20, i.e., between the oil outlet of the compressor body 16 and the second portion 24b of the water-cooled heat exchanger 24, and may measure the temperature of the oil after it is discharged from the compressor body 16 (i.e., immediately after it is heated by the heat of compression of the refrigerant gas in the compressor body 16). In this way, the temperature of the oil before it is cooled by the water-cooled heat exchanger 24 can be measured.

[0037] Additionally or alternatively, a further oil temperature sensor may be arranged downstream of the air-cooled heat exchanger 26 in the oil circulation line 20, i.e., between the air-cooled heat exchanger 26 and the oil inlet of the compressor body 16, to measure the temperature of the oil cooled by the air-cooled heat exchanger 26.

[0038] In addition to or instead of the oil temperature sensor, at least one refrigerant gas temperature sensor may be provided as the temperature sensor 50. The refrigerant gas temperature sensor may be disposed in the discharge flow path 32 between the compressor body 16 and the water-cooled heat exchanger 24, between the water-cooled heat exchanger 24 and the air-cooled heat exchanger 26, or between the air-cooled heat exchanger 26 and the oil separator 34, and may measure the refrigerant gas temperature at the installation location.

[0039] The cryogenic refrigerator 10 may also include at least one pressure sensor, such as a first pressure sensor 52a and a second pressure sensor 52b, that measures the pressure of the refrigerant gas. The first pressure sensor 52a is configured to measure the pressure of the refrigerant gas supplied from the compressor 12 to the cold head 14. The first pressure sensor 52a is connected to the discharge passage 32 to measure the pressure of the refrigerant gas flowing through the discharge passage 32. Alternatively, the first pressure sensor 52a may be connected to the high-pressure pipe 42. The second pressure sensor 52b is configured to measure the pressure of the refrigerant gas recovered from the cold head 14 to the compressor 12. The second pressure sensor 52b is connected to the suction passage 33 to measure the pressure of the refrigerant gas flowing through the suction passage 33. Alternatively, the second pressure sensor 52b may be connected to the low-pressure pipe 43. Therefore, the first pressure sensor 52a and the second pressure sensor 52b may also be referred to as a high-pressure sensor and a low-pressure sensor, respectively.

[0040] The cryogenic refrigerator 10 may include a controller 60. The controller 60 is configured to acquire measurement data from at least one sensor of the cryogenic refrigerator 10 and control the cryogenic refrigerator 10 (i.e., the compressor 12 and / or the cold head 14) based on the measurement data. The sensor may be, for example, a temperature sensor 50, a first pressure sensor 52a, a second pressure sensor 52b, and / or at least one sensor provided in the cold head 14 (e.g., a temperature sensor measuring the temperature of the low-temperature section 14b). As illustrated in FIG. 1 , the controller 60 may be installed in the compressor housing 28 and mounted on the compressor 12.

[0041] The controller 60 may include an inverter 62 that controls the compressor motor 16a. The inverter 62 is configured to convert input power supplied from an external power source such as a commercial power source (e.g., a three-phase AC power source) into output power that drives the compressor motor 16a and output the power to the compressor motor 16a. The frequency of the output power from the inverter 62, i.e., the operating frequency of the compressor motor 16a, can be changed within a range of 30 Hz to 100 Hz or a range of 40 Hz to 70 Hz depending on the inverter 62. The compressor motor 16a can operate at a rotation speed that corresponds to the output frequency of the inverter 62.

[0042] The controller 60 may control the output frequency of the inverter 62 so as to maintain the differential pressure between the high pressure of the cryogenic refrigerator 10 measured by the first pressure sensor 52a and the low pressure of the cryogenic refrigerator 10 measured by the second pressure sensor 52b at a differential pressure target value. For example, the controller 60 may compare the differential pressure with the differential pressure target value, and control the inverter 62 to increase the operating frequency of the compressor motor 16a when the differential pressure exceeds the target value, and decrease the operating frequency of the compressor motor 16a when the differential pressure is below the target value.

[0043] Alternatively, the controller 60 may control the output frequency of the inverter 62 so as to maintain the high pressure of the cryogenic refrigerator 10 measured by the first pressure sensor 52a at a high pressure target value. Alternatively, the controller 60 may control the output frequency of the inverter 62 so as to maintain the low pressure of the cryogenic refrigerator 10 measured by the second pressure sensor 52b at a low pressure target value.

[0044] The compressor 12 may be provided with another motor (e.g., a motor that drives the cooling fan 26a) whose operating frequency is variable. The controller 60 may further include an inverter that controls the other motor provided in the compressor 12. For example, the controller 60 may control this inverter so as to maintain the temperature measured by the temperature sensor 50 at a target temperature. The cold head 14 may also be provided with a cold head drive motor whose operating frequency is variable. The controller 60 may further include an inverter that controls the cold head drive motor. For example, the controller 60 may control the inverter for the cold head drive motor so as to maintain the temperature measured by a temperature sensor provided in the low-temperature section 14b of the cold head 14 at a target temperature.

[0045] The cryogenic refrigerator 10 may include a timer 64. The timer 64 may be provided in, for example, the controller 60. The timer 64 is configured to measure the operating time of the cryogenic refrigerator 10 (i.e., the elapsed time from when the cryogenic refrigerator 10 started operating to the present). Thus, the timer 64 can measure the time from when the cryogenic refrigerator 10 is turned on (i.e., when operation starts) to when it is turned off (i.e., when operation stops).

[0046] The timer 64 may also be configured to measure the downtime during which the cryogenic refrigerator 10 is not in operation (i.e., the elapsed time from when the cryogenic refrigerator 10 stopped operating to the present). Thus, the timer 64 can measure the time from when the cryogenic refrigerator 10 was turned off to when it was turned on.

[0047] The cryogenic refrigerator 10 may be provided with a main switch 66. The main switch 66 is a switch for switching the cryogenic refrigerator 10 on and off. When the main switch 66 is on, the compressor 12 and the cold head 14 operate, and when the main switch 66 is off, the operation of the compressor 12 and the cold head 14 is stopped. The timer 64 may measure the time that the main switch 66 is on as the operating time of the cryogenic refrigerator 10, and may measure the time that the main switch 66 is off as the rest time of the cryogenic refrigerator 10.

[0048] The controller 60 may be configured to acquire operation history data of the cryogenic refrigerator 10. The operation history data of the cryogenic refrigerator 10 may include a measured operation time of the cryogenic refrigerator 10 and an operation state of the cryogenic refrigerator 10 during the measured operation time.

[0049] The controller 60 may obtain from the timer 64 the operation time of the cryogenic refrigerator 10 measured by the timer 64. In addition to this, or instead, the controller 60 may obtain from the timer 64 the rest time of the cryogenic refrigerator 10 measured by the timer 64.

[0050] The operating state of the cryogenic refrigerator 10 may include the operating frequency of a motor (e.g., compressor motor 16a) provided in the cryogenic refrigerator 10. Additionally or alternatively, the operating state of the cryogenic refrigerator 10 may include the temperature measured by a temperature sensor (e.g., temperature sensor 50) provided in the cryogenic refrigerator 10. Additionally or alternatively, the operating state of the cryogenic refrigerator 10 may include the pressure measured by a pressure sensor (e.g., first pressure sensor 52a and / or second pressure sensor 52b) provided in the cryogenic refrigerator 10.

[0051] The controller 60 may periodically acquire the operating state of the cryogenic refrigerator 10 while the cryogenic refrigerator 10 is operating (i.e., while the operating time is being measured by the timer 64), and associate the measured operating time with the acquired operating state during this operating time. In this way, the controller 60 may acquire operating history data of the cryogenic refrigerator 10 during this operating time.

[0052] For example, the controller 60 may obtain the operating frequency of a motor (e.g., compressor motor 16a) from the motor or an inverter (e.g., inverter 62) controlling the motor. The controller 60 or the inverter may be considered as a sensor measuring the operating frequency of the motor. The controller 60 may obtain the measured temperature of the cryogenic refrigerator 10 from a temperature sensor (e.g., temperature sensor 50). The controller 60 may obtain the measured pressure of the cryogenic refrigerator 10 from a pressure sensor (e.g., first pressure sensor 52a and / or second pressure sensor 52b).

[0053] 2 is a block diagram showing a schematic configuration of a maintenance support system 100 for a cryogenic refrigerator 10 according to an embodiment. The maintenance support system 100 includes at least one cryogenic refrigerator 10 and a maintenance support device 70 including a processor 72.

[0054] The processor 72 is configured to acquire operation history data D1 of the cryogenic refrigerator 10, and determine a maintenance plan for the cryogenic refrigerator 10 based on the operation history data D1. As will be described in detail later, the processor 72 may be configured to calculate a corrected operation time for the cryogenic refrigerator 10 by increasing or decreasing the measured operation time based on the operating state of the cryogenic refrigerator 10 during this measured operation time, and to determine a maintenance plan for the cryogenic refrigerator 10 based on the calculated corrected operation time of the cryogenic refrigerator 10.

[0055] In this embodiment, the maintenance support device 70 is located remotely from the cryogenic refrigerator 10 and is communicatively connected to the cryogenic refrigerator 10 (for example, the controller 60) via, for example, the Internet or any other suitable communication network 80.

[0056] The cryogenic refrigerator 10 may be configured to output the operation history data D1 to a communication network 80, and the maintenance support device 70 may be configured to receive the operation history data D1 from the cryogenic refrigerator 10 via the communication network 80. Furthermore, the maintenance support device 70 may be configured to output maintenance plan data D2 representing a determined maintenance plan for the cryogenic refrigerator 10, and the cryogenic refrigerator 10 may be configured to receive the maintenance plan data D2 from the maintenance support device 70 via the communication network 80.

[0057] The cryogenic refrigerator 10 may be provided with a notification unit 68 that visually notifies information indicating the determined maintenance plan for the cryogenic refrigerator 10, and the notification unit 68 may include, for example, a display or a warning light. The notification unit 68 may also notify the maintenance plan audibly, for example, via a speaker. The notification unit 68 may be configured to notify the maintenance plan based on maintenance plan data D2 acquired from the maintenance support device 70. In addition to or instead of providing the notification unit 68 in the cryogenic refrigerator 10, the notification unit 68 may also be provided in the maintenance support device 70.

[0058] The maintenance support system 100 may include an external storage 82 connected to the cryogenic refrigerator 10 and the maintenance support device 70 via a communication network 80. The external storage 82 may receive the operation history data D1 from the cryogenic refrigerator 10 via the communication network 80 and store the received operation history data D1. The maintenance support device 70 may acquire the operation history data D1 from the external storage 82 via the communication network 80. The external storage 82 may also receive the maintenance plan data D2 from the maintenance support device 70 via the communication network 80 and store the received maintenance plan data D2. The cryogenic refrigerator 10 may acquire the maintenance plan data D2 from the external storage 82 via the communication network 80.

[0059] In an exemplary usage scenario, the maintenance support device 70 may be under the control of the manufacturer of the cryogenic refrigerator 10 or a service provider that provides maintenance services such as repairs for the cryogenic refrigerator 10. The external storage 82 may be under the control of the manufacturer of the cryogenic refrigerator 10, a service provider, or a third party. Meanwhile, the cryogenic refrigerator 10 may be under the control of a user of the cryogenic refrigerator 10.

[0060] The internal configuration of the controller 60 of the cryogenic refrigerator 10 and the processor 72 of the maintenance support device 70 is realized as a hardware configuration using elements and circuits such as a computer's CPU (Central Processing Unit) and memory, and as a software configuration using a computer program, etc., but in the figure they are depicted as functional blocks realized by the cooperation of these elements. Those skilled in the art will understand that these functional blocks can be realized in various ways by combining hardware and software.

[0061] 3 is a flowchart showing a maintenance support method for the cryogenic refrigerator 10 according to the embodiment. This method includes acquiring operation history data D1 of the cryogenic refrigerator 10 (S10), calculating a corrected operation time of the cryogenic refrigerator 10 based on the operation history data D1 (S20), and determining a maintenance plan for the cryogenic refrigerator 10 based on the corrected operation time of the cryogenic refrigerator 10 (S30).

[0062] In S10, operation history data D1 is acquired from the cryogenic refrigerator 10. The maintenance support device 70 may periodically acquire the operation history data D1 from the cryogenic refrigerator 10. As described above, the operation history data D1 may include the measured operation time of the cryogenic refrigerator 10 and the operation state of the cryogenic refrigerator 10 during the measured operation time (e.g., the operation frequency of the compressor motor 16a, the temperature of the compressor 12, the refrigerant gas pressure in the compressor 12, etc.).

[0063] In S20, the corrected operating time of the cryogenic refrigerator 10 is calculated by increasing or decreasing the measured operating time of the cryogenic refrigerator 10 based on the operating state of the cryogenic refrigerator 10 during this measured operating time.

[0064] In one example of calculating the corrected operating time of the cryogenic refrigerator 10, the operating frequency of the compressor motor 16a may be used as the operating state of the cryogenic refrigerator 10. In this case, the processor 72 may be configured to calculate the corrected operating time of the cryogenic refrigerator 10 by increasing or decreasing the measured operating time based on the operating frequency of the compressor motor 16a.

[0065] For example, the processor 72 may be configured to calculate a corrected operating time of the cryogenic refrigerator 10 by comparing the acquired operating frequency of the motor with a reference operating frequency and increasing or decreasing the measured operating time based on the comparison. A load factor may be determined based on the comparison of the operating frequency of the motor with the reference operating frequency, and the corrected operating time of the cryogenic refrigerator 10 may be calculated by multiplying the measured operating time by the load factor. The larger the difference between the operating frequency of the motor and the reference operating frequency, the larger the load factor may be. When the operating frequency of the motor is higher than the reference operating frequency, the load factor may be greater than 1, and when the operating frequency of the motor is lower than the reference operating frequency, the load factor may be less than 1.

[0066] As an example, the reference operating frequency may be 60 Hz, and the load coefficient may be a value obtained by dividing the operating frequency of the compressor motor 16a by 60. In this example, if the cryogenic refrigerator 10 is operated for one hour with the operating frequency of the compressor motor 16a set to 60 Hz, the corrected operating time is one hour, which is the product of the measured operating time (one hour) and the load coefficient (1 = 60 / 60). In other words, in this case, since the actual operating frequency is equal to the reference operating frequency, the corrected operating time is also equal to the actually measured operating time. On the other hand, if the cryogenic refrigerator 10 is operated for one hour with the operating frequency of the compressor motor 16a set to 30 Hz, the corrected operating time is 0.5 hours, which is the product of the measured operating time (one hour) and the load coefficient (0.5 = 30 / 60). The corrected operating time is shorter than the actually measured operating time because the operating load of the cryogenic refrigerator 10 is lighter than the reference. Conversely, when the cryogenic refrigerator 10 is operated at an operating frequency higher than the reference operating frequency, the corrected operating time is longer than the actually measured operating time. In this way, the corrected operating time is an index that reflects the operating load of the cryogenic refrigerator 10.

[0067] The operating frequency of another variable frequency motor provided in the cryogenic refrigerator 10 may be used to calculate the corrected operating time. For example, instead of the compressor motor 16a, the operating frequency of a motor that drives the cooling fan 26a of the air-cooled heat exchanger 26 may be used to calculate the corrected operating time. Alternatively, the operating frequency of the cold head drive motor may be used to calculate the corrected operating time.

[0068] In calculating the corrected operating time of the cryogenic refrigerator 10, a measured temperature (e.g., the measured temperature of the compressor 12) may be used as the operating state of the cryogenic refrigerator 10. This is because a high temperature indicates that the operating load of the cryogenic refrigerator 10 is high. In this case, the processor 72 may be configured to calculate the corrected operating time of the cryogenic refrigerator 10 by increasing or decreasing the measured operating time based on the measured temperature. A load coefficient may be determined based on a comparison between the measured temperature and a reference temperature, and the corrected operating time of the cryogenic refrigerator 10 may be calculated by multiplying the measured operating time by the load coefficient. The measured temperature for determining the load coefficient may be an average value of the measured temperatures during the actually measured operating time. A predetermined reference temperature may be used as the reference temperature. Alternatively, the average value of the measured temperatures during past operations may be used as the reference temperature.

[0069] The greater the difference between the measured temperature and the reference temperature, the greater the load factor may be. When the measured temperature is above the reference temperature, the load factor may be greater than 1, and when the measured temperature is below the reference temperature, the load factor may be less than 1. For example, when the measured temperature is 10% or more above the reference temperature, the load factor may be 1.1, and when the measured temperature is 10% or more below the reference temperature, the load factor may be 0.9.

[0070] Similarly, when calculating the corrected operating time of the cryogenic refrigerator 10, a measured pressure (e.g., a differential pressure between the high pressure and the low pressure of the cryogenic refrigerator 10) may be used as the operating state of the cryogenic refrigerator 10. In this case, the processor 72 may be configured to calculate the corrected operating time of the cryogenic refrigerator 10 by increasing or decreasing the measured operating time based on the measured pressure. A load factor may be determined based on a comparison between the measured pressure and a reference pressure, and the corrected operating time of the cryogenic refrigerator 10 may be calculated by multiplying the measured operating time by the load factor. The larger the difference between the measured pressure and the reference pressure, the larger the load factor may be. When the measured pressure is higher than the reference pressure, the load factor may be greater than 1, and when the measured pressure is lower than the reference pressure, the load factor may be less than 1.

[0071] When the cryogenic refrigerator 10 is started, a so-called cool-down is performed in which the cryogenic refrigerator 10 is rapidly cooled from an initial temperature (usually an ambient temperature such as room temperature) to a desired cryogenic temperature. During the cool-down, the operating pressure of the cryogenic refrigerator 10 (for example, the differential pressure between the high pressure and the low pressure of the cryogenic refrigerator 10) may be higher than that during steady operation after the cool-down. Therefore, for the time when the cool-down is performed, the load coefficient may be set to a value greater than 1 (for example, a relatively large value such as 1.2).

[0072] In S30, an integrated value of the corrected operating time (hereinafter also referred to as the integrated corrected operating time) may be calculated. Then, the integrated value of the corrected operating time may be compared with a preset maintenance interval, and a maintenance plan for the cryogenic refrigerator 10 may be determined based on this comparison. The preset maintenance interval may be, for example, tens of thousands of hours. Calculating the integrated corrected operating time may include updating the integrated corrected operating time, for example, by adding the corrected operating time calculated in S20 to a previously calculated integrated corrected operating time. When maintenance is performed, the count of the integrated corrected operating time may be reset.

[0073] The processor 72 may determine whether maintenance of the cryogenic refrigerator 10 is required based on a comparison between the updated accumulated corrected operating time and a preset maintenance interval. If the updated accumulated corrected operating time exceeds the maintenance interval, the processor 72 may determine that maintenance of the cryogenic refrigerator 10 is required. If the updated accumulated corrected operating time does not exceed the maintenance interval, the processor 72 may determine that maintenance of the cryogenic refrigerator 10 is not currently required. Alternatively, if the difference between the accumulated corrected operating time and the maintenance interval is less than a predetermined threshold time, the processor 72 may determine that the maintenance interval is about to expire (i.e., the time for the next maintenance is approaching).

[0074] Comparing the accumulated corrected operating time with the preset maintenance interval may include calculating a remaining maintenance time, which is the difference between the preset maintenance interval and a previously calculated accumulated corrected operating time, and comparing the calculated remaining maintenance time with the corrected operating time calculated in S20. The remaining maintenance time is the time remaining from the current time until the next maintenance due date determined from the maintenance interval. Processor 72 may update the remaining maintenance time by subtracting the corrected operating time from the remaining maintenance time.

[0075] In this case, the processor 72 may determine whether maintenance of the cryogenic refrigerator 10 is necessary based on a comparison between the remaining maintenance time and the corrected operating time. If the corrected operating time exceeds the remaining maintenance time, the processor 72 may determine that maintenance of the cryogenic refrigerator 10 is necessary. If the corrected operating time does not exceed the remaining maintenance time, the processor 72 may determine that maintenance of the cryogenic refrigerator 10 is not currently necessary. Alternatively, if the remaining maintenance time is below a predetermined threshold time, the processor 72 may determine that the maintenance interval is about to expire (i.e., the time for the next maintenance is approaching).

[0076] The maintenance plan data D2 may include information indicating the necessity of maintenance of the cryogenic refrigerator 10 thus determined. The maintenance support device 70 can provide the information indicating the necessity of maintenance of the cryogenic refrigerator 10 to the user of the cryogenic refrigerator 10 using the notification unit 68. Because the maintenance plan data D2 is determined based on the corrected operating time that reflects the operating load of the cryogenic refrigerator 10, the maintenance support device 70 can support the determination of an efficient maintenance plan according to the actual operating status of the cryogenic refrigerator 10.

[0077] The maintenance support device 70 also helps the manufacturer or service provider of the cryogenic refrigerator 10 to remotely determine whether maintenance is required for the cryogenic refrigerator 10. This allows the manufacturer or service provider of the cryogenic refrigerator 10 to support the user of the cryogenic refrigerator 10 in performing appropriate maintenance.

[0078] The maintenance interval of the cryogenic refrigerator 10 is determined by the manufacturer of the cryogenic refrigerator 10 to suit the relatively severe operating conditions of the cryogenic refrigerator 10 (for example, applications in which the cryogenic refrigerator 10 is operated continuously at all times). Therefore, for example, if the operating rate of the cryogenic refrigerator 10 is relatively low, such as applications in which the cryogenic refrigerator 10 is repeatedly operated and stopped, a longer maintenance interval may be acceptable.

[0079] Therefore, the operation history data D1 may include downtime of the cryogenic refrigerator 10 in addition to the measured operation time of the cryogenic refrigerator 10. The processor 72 may be configured to determine a maintenance plan for the cryogenic refrigerator 10 by taking into account the ratio of operation time to the sum of operation time and downtime (i.e., the operation rate of the cryogenic refrigerator 10). For example, the processor 72 may be configured to increase or decrease the corrected operation time of the cryogenic refrigerator 10 depending on the operation rate of the cryogenic refrigerator 10, and to determine a maintenance plan for the cryogenic refrigerator 10 based on the corrected operation time thus obtained. In this way, the maintenance support device 70 can support the determination of a more efficient maintenance plan.

[0080] For example, if the calculated remaining maintenance time is one month, this may mean that the next maintenance should be performed one month from the present time if the cryogenic refrigerator 10 is operated at 100% availability (i.e., 24 hours a day). Therefore, if the actual availability of the cryogenic refrigerator 10 is lower than this, a longer remaining maintenance time may be acceptable. For example, if the cryogenic refrigerator 10 is operated at 50% availability (e.g., 12 hours a day), the next maintenance may be performed two months from the present time.

[0081] The processor 72 may also be configured to calculate an index indicating the degree of wear of replacement parts of the cryogenic refrigerator 10 based on the operation history data D1 of the cryogenic refrigerator 10, and to determine a maintenance plan for the cryogenic refrigerator 10 based on this index. Examples of replacement parts include the adsorber 35 in the compressor 12, bearings in a motor (e.g., compressor motor 16a), and oil in the compressor 12. The processor 72 may compare the calculated index with a threshold value and determine whether or not replacement of the replacement part is necessary based on this comparison. In this way, the replacement timing for each replacement part can be determined individually, which can be used to determine a maintenance plan.

[0082] For example, the index for the advertiser 35 in the compressor 12 may be the amount of oil accumulated in the advertiser 35. This amount of accumulated oil can be calculated based on the operating conditions of the cryogenic refrigerator 10 (for example, the operating frequency of the compressor motor 16a, the temperature of the compressor 12, and the refrigerant gas pressure in the compressor 12). In addition, a threshold value for determining whether replacement is necessary can be given as a specification of the advertiser 35.

[0083] The processor 72 may also be configured to diagnose the cryogenic refrigerator 10 based on the operation history data D1 of the cryogenic refrigerator 10, and to determine a maintenance plan for the cryogenic refrigerator 10 based on the diagnosis results. An existing diagnostic method can be used to diagnose the cryogenic refrigerator 10 based on the operating state of the cryogenic refrigerator 10. In this way, the maintenance support device 70 can monitor the health of the cryogenic refrigerator 10 (for example, detect an abnormality in the cryogenic refrigerator 10 or predict the occurrence of an abnormality) based on the operating state of the cryogenic refrigerator 10, and reflect the results in the maintenance plan. In addition to regular maintenance based on the maintenance interval, additional maintenance can be performed to address an abnormality in the cryogenic refrigerator 10.

[0084] 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-described embodiments, and that various design changes and modifications are possible, and that such modifications are also within the scope of the present invention. Various features described in relation to one embodiment can also be applied to other embodiments. A new embodiment created by combining embodiments will have the combined effects of the respective combined embodiments.

[0085] In the above-described embodiment, an example has been described in which the processor 72 of the maintenance support device 70 calculates the corrected operating time of the cryogenic refrigerator 10. However, other configurations are also possible. For example, the cryogenic refrigerator 10 may include a processor configured to acquire the measured operating time of the cryogenic refrigerator 10 and the operating state of the cryogenic refrigerator 10 during the measured operating time, and calculate the corrected operating time of the cryogenic refrigerator 10 by increasing or decreasing the measured operating time based on the operating state of the cryogenic refrigerator 10 during the measured operating time. The controller 60 may be configured to operate as such a processor. In this case, the processor 72 of the maintenance support device 70 may be configured to acquire the calculated corrected operating time of the cryogenic refrigerator 10 (e.g., via the communication network 80), and determine a maintenance plan for the cryogenic refrigerator based on the acquired corrected operating time of the cryogenic refrigerator.

[0086] In the above embodiment, an example has been described in which the maintenance support device 70 is located remotely from the cryogenic refrigerator 10, but other configurations are also possible. For example, the cryogenic refrigerator 10 and the maintenance support device 70 may be located close to each other. Alternatively, the cryogenic refrigerator 10 and the maintenance support device 70 may be integrated. In this case, both the cryogenic refrigerator 10 and the maintenance support device 70 may be under the control of the user of the cryogenic refrigerator 10.

[0087] The present invention has been described using specific terms based on the embodiments, but the embodiments merely illustrate one aspect of the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiments as long as they do not deviate from the concept of the present invention as defined in the claims. [Explanation of symbols]

[0088] 10 cryogenic refrigerator, 16a compressor motor, 50 temperature sensor, 52a first pressure sensor, 52b second pressure sensor, 60 controller, 64 timer, 70 maintenance support device, 72 processor, 80 communication network, 100 maintenance support system, D1 operation history data.

Claims

1. a processor configured to acquire operating history data of a cryogenic refrigerator and determine a maintenance plan for the cryogenic refrigerator based on the operating history data; the operation history data of the cryogenic refrigerator includes a measured operation time of the cryogenic refrigerator and an operation state of the cryogenic refrigerator during the measured operation time; The processor: calculating a corrected operating time of the cryogenic refrigerator by increasing or decreasing the measured operating time based on an operating state of the cryogenic refrigerator during the measured operating time; A cryogenic refrigerator maintenance support device configured to determine a maintenance plan for the cryogenic refrigerator based on a corrected operation time of the cryogenic refrigerator.

2. The processor: Calculating an integrated value of the corrected operating time, 2. The cryogenic refrigerator maintenance support device according to claim 1, configured to determine a maintenance plan for the cryogenic refrigerator based on a comparison between the integrated value of the corrected operating time and a preset maintenance interval.

3. the operation history data includes a measured operation time of the cryogenic refrigerator as well as a downtime of the cryogenic refrigerator; 3. The cryogenic refrigerator maintenance support device according to claim 1, wherein the processor is configured to determine a maintenance plan for the cryogenic refrigerator by taking into account a ratio of the operating time to the sum of the operating time and the downtime.

4. The cryogenic refrigerator includes a motor with a variable operating frequency, the operating state of the cryogenic refrigerator includes an operating frequency of the motor; 3. The cryogenic refrigerator maintenance support device according to claim 1, wherein the processor is configured to calculate a corrected operation time of the cryogenic refrigerator by increasing or decreasing the measured operation time based on an operation frequency of the motor.

5. The processor: calculating an index indicating a degree of wear of a replacement part of the cryogenic refrigerator based on operation history data of the cryogenic refrigerator; 3. The cryogenic refrigerator maintenance support device according to claim 1, wherein the cryogenic refrigerator maintenance support device is configured to determine a maintenance plan for the cryogenic refrigerator based on the index.

6. The processor: Diagnosing the cryogenic refrigerator based on operation history data of the cryogenic refrigerator; 3. The cryogenic refrigerator maintenance support device according to claim 1, wherein the cryogenic refrigerator maintenance support device is configured to determine a maintenance plan for the cryogenic refrigerator based on a diagnosis result.

7. 3. The cryogenic refrigerator maintenance support device according to claim 1, wherein the cryogenic refrigerator maintenance support device is disposed remotely from the cryogenic refrigerator and configured to receive the operation history data via a communication network.

8. Obtaining a measured operating time of a cryogenic refrigerator and an operating state of the cryogenic refrigerator during the measured operating time; calculating a corrected operating time of the cryogenic refrigerator by increasing or decreasing the measured operating time based on an operating state of the cryogenic refrigerator during the measured operating time; determining a maintenance plan for the cryogenic refrigerator based on the corrected operating time of the cryogenic refrigerator.

9. A timer that measures the operating time of the cryogenic refrigerator, at least one sensor for measuring the operating state of the cryogenic refrigerator; a processor configured to acquire a measured operating time of the cryogenic refrigerator and an operating state of the cryogenic refrigerator during the measured operating time, and to calculate a corrected operating time of the cryogenic refrigerator by increasing or decreasing the measured operating time based on the operating state of the cryogenic refrigerator during the measured operating time.

Images