Compressor unit of cryogenic refrigerator

Abstract

The utility model aims to improve the energy-saving performance of a cryogenic refrigerator. The utility model provides a compressor unit of a cryogenic refrigerator. The compressor unit comprises a compressor motor; an inverter (60) that converts alternating current input from an external power source to the compressor unit into a drive power source for the compressor motor; a transformer (62) for converting the alternating current into a driving power source for the cold head of the cryogenic refrigerator having a voltage different from the voltage of the alternating current; and a control panel (50) on which the inverter (60) and the transformer (62) are mounted. The transformer (62) may be disposed below the inverter (60).

Description

[0001] This application claims priority based on Japanese Patent Application No. 2024-011966, filed January 30, 2024. The entire contents of that Japanese application are incorporated herein by reference. Technical Field

[0002] This utility model relates to a compressor unit for an ultra-low temperature refrigeration machine. Background Technology

[0003] Typically, cryogenic refrigerators such as Gifford-McMahon (GM) refrigerators have a refrigerant gas compressor to supply high-pressure refrigerant gas to the cold head. The compressor consists of components such as the compressor body, oil separator, adsorber, storage tank, and control device.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2001-74326

[0005] In the aforementioned cryogenic refrigeration unit, the motor driving the compressor operates at a constant speed. Summary of the Invention

[0006] One of the exemplary objectives of one embodiment of this utility model is to improve the energy efficiency of cryogenic refrigerators.

[0007] According to one embodiment of the present invention, the compressor unit of the cryogenic refrigeration machine includes: a compressor motor; a frequency converter that converts AC power input from an external power source into the compressor unit into a drive power source for the compressor motor; a transformer that converts AC power into a drive power source for the cold head of the cryogenic refrigeration machine having a voltage different from that of the AC power; and a control panel equipped with the frequency converter and the transformer.

[0008] According to this embodiment, since the compressor motor speed can be adjusted using a frequency converter, the energy efficiency of the compressor unit of the cryogenic refrigeration unit can be improved. Furthermore, although the input AC power may have different voltages depending on the country or region where the cryogenic refrigeration unit is used, it can be converted to a voltage suitable for the cold head using a transformer, and the compressor unit can be used as a power source for the cold head.

[0009] The frequency converter may have a frequency converter exhaust port, which serves as an outlet for cooling air from the frequency converter, and the frequency converter is mounted on the control panel such that the frequency converter exhaust port is positioned above the transformer.

[0010] The transformer can be positioned lower than the frequency converter.

[0011] The compressor unit can also be equipped with a switching power supply that converts AC to DC power. The control panel can be equipped with a switching power supply.

[0012] The frequency converter may have a frequency converter exhaust port, which serves as an outlet for cooling air from the frequency converter, and the frequency converter is mounted on a control panel such that the frequency converter exhaust port is positioned above the switching power supply.

[0013] The compressor unit may also include a noise filter and a DC reactor connected to the frequency converter. The control panel may also be equipped with a noise filter and a DC reactor.

[0014] The frequency converter may have a frequency converter exhaust port, which serves as an outlet for cooling air from the frequency converter, and the frequency converter is mounted on a control panel such that the frequency converter exhaust port is positioned above the noise filter and DC reactor.

[0015] The noise filter and the DC reactor can be positioned below the frequency converter and above the transformer.

[0016] The frequency converter may have a frequency converter exhaust port, which serves as the outlet for cooling air from the frequency converter. The compressor unit may also have a compressor unit housing with a housing exhaust port serving as the outlet for cooling air from the compressor unit, and housing the compressor motor and control panel. The control panel may have an exhaust passage defining a flow path for cooling air from the frequency converter exhaust port to the housing exhaust port. The exhaust passage has a passage inlet component adjacent to the frequency converter exhaust port and a passage outlet component adjacent to the housing exhaust port; the passage inlet component can be detached from the passage outlet component and the frequency converter.

[0017] The compressor unit housing may have a housing air inlet, which is positioned below the housing exhaust port and serves as the inlet for cooling air to reach the compressor unit.

[0018] Compared to transformers, frequency converters can be configured closer to the exhaust port of the housing, while transformers can be configured closer to the air inlet of the housing.

[0019] The compressor unit can be placed in an area with a width of less than 600mm and a length of less than 500mm.

[0020] Invention Effects

[0021] According to this utility model, the energy efficiency of ultra-low temperature refrigeration machines can be improved. Attached Figure Description

[0022] Figure 1 This is a diagram that roughly illustrates the cryogenic refrigerator involved in the implementation method.

[0023] Figure 2This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0024] Figure 3 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0025] Figure 4 This is a schematic top view showing the equipment configuration within the compressor unit of the cryogenic refrigerator according to the embodiment.

[0026] Figure 5 This is a block diagram that roughly represents the control panel of the compressor unit involved in the implementation method.

[0027] Figure 6 This is a diagram that roughly shows the appearance of the compressor unit involved in the embodiment.

[0028] Figure 7 This is a diagram that roughly illustrates the device configuration on the control panel of the compressor unit involved in the embodiment.

[0029] Figure 8 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0030] Figure 9 This is a diagram that roughly illustrates the device configuration on the control panel of the compressor unit involved in the embodiment.

[0031] Figure 10 This is a diagram that schematically illustrates another example of an exhaust passage mounted on a control panel according to an embodiment.

[0032] In the diagram: 10-Cryogenic Refrigeration Unit, 12-Compressor, 14-Cold Head, 24-Compressor Unit Frame, 28-Compressor Motor, 50-Control Panel, 60-Inverter, 62-Transformer, 64-Noise Filter, 66-DC Reactor, 68-Switching Power Supply, 72-Frame Air Inlet, 74-Frame Exhaust Port, 78-Inverter Exhaust Port, 80-Exhaust Channel. Detailed Implementation

[0033] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings. In the following description and drawings, identical or equivalent constituent elements, components, and processes are labeled with the same symbols, and repeated descriptions are omitted where appropriate. In the drawings, for ease of explanation, scales or shapes of various parts are appropriately shown, which are not intended to be limiting unless specifically mentioned otherwise. The embodiments are illustrative and do not limit the scope of this utility model in any way. All features or combinations thereof described in the embodiments are not necessarily the essence of the utility model.

[0034] Figure 1This is a schematic diagram illustrating the cryogenic refrigerator involved in the embodiment. The cryogenic refrigerator 10 is used to provide cryogenic cooling to an object or medium. For example, the cryogenic refrigerator 10 can be used as a cooling source for a superconducting magnet device. The superconducting magnet device can be mounted on a strong magnetic field utilization device, for example, as a magnetic field source for a single crystal pulling device, an NMR (Nuclear Magnetic Resonance) system, an MRI (Magnetic Resonance Imaging) system, an accelerator such as a cyclotron, a high-energy physics system such as a nuclear fusion system, or other strong magnetic field utilization device (not shown), thereby generating the strong magnetic field required by the device.

[0035] The cryogenic refrigerator 10 includes a compressor 12 and a cold head 14. The compressor 12 is configured to recover refrigerant gas from the cold head 14, pressurize the recovered refrigerant gas, and then supply it 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 cryogenic section 14b, the cryogenic section 14b being also referred to as a cooling platform. The refrigerant gas is also referred to as the working gas, typically helium, but other suitable gases can also be used. The compressor 12 and the cold head 14 constitute the refrigeration cycle of the cryogenic refrigerator 10, thereby cooling the cryogenic section 14b to the desired cryogenic temperature. The cryogenic section 14b can, for example, cool objects such as superconducting magnets.

[0036] As an example, the cryogenic refrigerator 10 is a single-stage or two-stage Gifford-McMahon (GM) refrigerator, but it can also be a pulse tube refrigerator, a Stirling refrigerator, or other types of cryogenic refrigerators. The cold head 14 has a different structure depending on the type of cryogenic refrigerator 10, but the compressor 12 can use the structure described below regardless of the type of cryogenic refrigerator 10.

[0037] Furthermore, the pressure of the refrigerant gas supplied from compressor 12 to cold head 14 and the pressure of the refrigerant gas returned from cold head 14 to compressor 12 are typically much 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 will be simply referred to as high pressure and 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, for example, about 0.8 MPa.

[0038] The compressor 12 is an oil-lubricated compressor for cryogenic refrigeration, comprising a compressor body 16, a refrigerant gas pipeline 18, and an oil circulation pipeline 20. For ease of understanding, in... Figure 1In the diagram, the refrigerant gas line 18 is represented by a solid line, and the oil circulation line 20 is represented by a dashed line. Furthermore, the compressor 12 includes a compressor unit frame 24 that houses the compressor body 16, the refrigerant gas line 18, and the oil circulation line 20, among other components of the compressor 12.

[0039] The compressor body 16 is configured to internally compress refrigerant gas drawn in through its suction port and discharge it through its discharge port. Oil is used in the compressor body 16 for cooling and lubrication, and the drawn-in refrigerant gas is directly exposed to this oil within the compressor body 16. Therefore, the refrigerant gas is discharged from the discharge port with a small amount of oil mixed in.

[0040] The compressor body 16 may employ, for example, a scroll pump, a rotary pump, or other pump that increases the pressure of the refrigerant gas. The compressor body 16 may be configured to discharge a constant flow rate of refrigerant gas. Alternatively, the compressor body 16 may be configured to allow for a variable flow rate of discharged refrigerant gas. The compressor body 16 is also referred to as a compression chamber.

[0041] The refrigerant gas line 18 includes a discharge port 30, a suction port 31, a discharge flow path 32, and a suction flow path 33. The discharge port 30 is an outlet for refrigerant gas on the compressor unit frame 24, provided for discharging refrigerant gas pressurized to high pressure by the compressor body 16 from the compressor 12. The suction port 31 is an inlet for refrigerant gas on the compressor unit frame 24, provided for receiving low-pressure refrigerant gas into the compressor 12. The discharge flow path 32 and the suction flow path 33 are housed within the compressor unit frame 24. The discharge port of the compressor body 16 is connected to the discharge port 30 via the discharge flow path 32, and the suction port 31 is connected to the suction port of the compressor body 16 via the suction flow path 33.

[0042] A 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 through a high-pressure pipe 42, and the low-pressure port 41 is connected to the suction port 31 through a low-pressure pipe 43.

[0043] An oil separator 34 and an adsorber 35 are provided on the discharge flow path 32. The purpose of the oil separator 34 is to separate oil from the refrigerant gas that has been mixed in with the refrigerant gas as it passes through the compressor body 16. The purpose of the adsorber 35 is to remove residual components such as vaporized oil or other contaminants from the refrigerant gas by adsorption. The oil separator 34 and the adsorber 35 are connected in series. On the discharge flow path 32, the oil separator 34 is located on the compressor body 16 side, and the adsorber 35 is located on the discharge port 30 side.

[0044] An oil return line 21 is provided, connecting the oil separator 34 to the compressor body 16. Through the oil return line 21, the oil recovered by the oil separator 34 can be returned to the compressor body 16. A filter to remove dust contained in the oil separated by the oil separator 34 and a throttling orifice to control the amount of oil returning to the compressor body 16 can be installed along the oil return line 21.

[0045] On the other hand, a reservoir 36 is provided on the suction flow path 33. The reservoir 36 is configured to remove the pulsating volume contained in the low-pressure refrigerant gas returning from the cold head 14 to the compressor 12.

[0046] Furthermore, a bypass valve 38 is provided on the refrigerant gas line 18, connecting the discharge flow path 32 to the suction flow path 33 in a manner that bypasses the compressor body 16. As an example, the bypass valve 38 branches off from the discharge flow path 32 between the oil separator 34 and the adsorber 35, and connects to the suction flow path 33 between the compressor body 16 and the storage tank 36. The purpose of the bypass valve 38 is to control the refrigerant gas flow rate and / or to equalize the pressure between the discharge flow path 32 and the suction flow path 33 when the compressor 12 stops.

[0047] The oil circulation line 20 connects the oil outlet of the compressor body 16 to the oil inlet, so that the oil flowing out of the compressor body 16 returns to the compressor body 16. A throttling orifice for controlling the flow rate of oil through the interior can be provided on the oil circulation line 20. Furthermore, a filter for removing dust contained in the oil can be provided on the oil circulation line 20.

[0048] Furthermore, the compressor 12 also includes a heat exchanger 22, which is housed within the compressor unit housing 24 and cools the compressor 12. The heat exchanger 22 includes: a refrigerant gas cooler 22a, which cools the refrigerant gas line 18 through heat exchange between the refrigerant gas and a cooling medium (e.g., cooling water); and an oil cooler 22b, which cools the oil circulation line 20 through heat exchange between the oil and a cooling medium.

[0049] A refrigerant gas cooler 22a is disposed between the compressor body 16 and the oil separator 34 on the discharge flow path 32 to cool the high-pressure refrigerant gas heated by the heat of compression generated during the compression of the refrigerant gas in the compressor body 16. The refrigerant gas cooler 22a cools the refrigerant gas through heat exchange between the refrigerant gas and the cooling medium. The cooled refrigerant gas is purified in the oil separator 34 and the adsorber 35. Furthermore, the oil cooler 22b cools the oil through heat exchange between the oil flowing from the oil outlet of the compressor body 16 to the oil circulation line 20 and the cooling medium. The cooled oil returns to the compressor body 16 from the oil inlet. The cooling medium is supplied to the compressor 12 from the outside through the cooling medium inlet 44 and is discharged to the outside of the compressor 12 from the cooling medium outlet 45 after passing through the refrigerant gas cooler 22a and the oil cooler 22b. The cooling medium can be a coolant, such as water. Thus, the heat of compression generated in the compressor body 16 is discharged to the outside of the compressor 12 along with the cooling medium. Alternatively, the cooling medium can be cooled by a chiller (not shown) and then resupplyed.

[0050] Furthermore, the cryogenic refrigerator 10 includes a control panel 50. The control panel 50 is mounted on the compressor 12 as a control device for controlling the cryogenic refrigerator 10. The control panel 50 may include a control circuit configured to receive outputs from various sensors installed on the cryogenic refrigerator 10 and control various devices of the cryogenic refrigerator 10 based on the sensor outputs. Multiple electrical components, including sensors, can be housed together with the control panel 50 within the compressor unit housing 24. Each sensor can be connected to the control panel 50 via a communication cable. Electrical components that control based on sensor outputs may include, for example, a compressor motor 28 driving the compressor body 16, a bypass valve 38, and a cold head motor driving the cold head 14.

[0051] Various sensors, such as pressure sensors and temperature sensors, can be installed on the compressor 12 to monitor its status. For example, a first pressure sensor 37a can be configured on the discharge path 32 to measure the pressure of the refrigerant gas flowing through the discharge path 32. The first pressure sensor 37a is configured to output a first measured pressure signal PH, indicating the measured pressure, to the control panel 50. Furthermore, a second pressure sensor 37b can be configured on the suction path 33 to measure the pressure of the refrigerant gas flowing through the suction path 33. The second pressure sensor 37b is configured to output a second measured pressure signal PL, indicating the measured pressure, to the control panel 50.

[0052] Temperature sensors may include a refrigerant gas temperature sensor installed on the refrigerant gas line 18, an oil temperature sensor installed on the oil circulation line 20, a coolant temperature sensor installed on the coolant piping of the heat exchanger 22, and a cooling temperature sensor installed on the low-temperature section 14b of the cold head 14. The temperature sensors are configured to output a signal indicating the measured temperature to the control panel 50.

[0053] For example, such as Figure 1 As shown, the first temperature sensor 46 is located upstream of the heat exchanger 22 on the discharge path 32 of the refrigerant gas line 18, measuring the temperature of the refrigerant gas flowing from the compressor body 16 into the heat exchanger 22. The second temperature sensor 47 is located downstream of the heat exchanger 22 on the refrigerant gas line 18, measuring the temperature of the refrigerant gas flowing from the heat exchanger 22 into the oil separator 34. The third temperature sensor 48 is located upstream of the heat exchanger 22 on the oil circulation line 20, measuring the temperature of the oil flowing from the compressor body 16 into the heat exchanger 22. The fourth temperature sensor 49 is located downstream of the heat exchanger 22 on the oil circulation line 20, measuring the temperature of the oil flowing from the heat exchanger 22 into the compressor body 16.

[0054] During the operation of the cryogenic refrigerator 10, refrigerant gas is supplied from the compressor 12 to the cold head 14. A refrigeration cycle (e.g., a GM cycle) is formed by the periodic volume changes of the expansion space of the refrigerant gas within the cold head 14 and the synchronous pressure changes of the refrigerant gas within the expansion space. The cryogenic section 14b of the cold head 14 is cooled to the desired cryogenic temperature. For example, in the case of a two-stage cold head 14, the first-stage cooling stage is cooled to a first cooling temperature in the range of approximately 30K to approximately 80K, and the second-stage cooling stage is cooled to a second cooling temperature lower than the first cooling temperature, for example, to 1K to 20K. The second cooling temperature can be approximately 4.2K of liquid helium or a temperature lower than that.

[0055] 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 is then returned to the suction port of the compressor body 16 after passing through the storage tank 36 on the suction path 33. The refrigerant gas is compressed and pressurized by the compressor body 16. At this time, the refrigerant gas heats up due to the heat of compression. The refrigerant gas discharged from the discharge port of the compressor body 16 is cooled in the refrigerant gas cooler 22a of the heat exchanger 22, and leaves the compressor 12 from the discharge port 30 after passing through the oil separator 34 and the adsorber 35. The refrigerant gas is supplied to the interior of the cold head 14 via the high-pressure piping 42 and the high-pressure port 40.

[0056] Figure 2 and Figure 3This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment. Figure 2 The image shown is a perspective view taken from the rear of the compressor 12. Figure 3 The front of compressor 12 is shown in the image.

[0057] like Figure 2 As shown, the compressor unit frame 24 is a cuboid with six sides, namely, it has a front panel 24a, a back panel 24b, a top panel 24c, a bottom panel 24d, and two side panels 24e and 24f. The back panel 24b faces the opposite side to the front panel 24a. Between the front panel 24a and the back panel 24b, the top panel 24c is positioned above, the bottom panel 24d is positioned below, and the side panels 24e and 24f are positioned on the left and right sides, respectively. These panels are sheet-like components made of stainless steel or other suitable materials.

[0058] The front panel 24a is configured to provide a user interface. For example... Figure 3 As shown, the front panel 24a is provided with an outlet port 30, an intake port 31, a cooling medium inlet 44, and a cooling medium outlet 45. Furthermore, the front panel 24a is also provided with an input power connector 51, a communication cable connector 52, a cold head connector 53, and a main switch 54.

[0059] As an example structure, the front panel 24a may have two panel portions that are combined to form the front panel 24a. Specifically, it may have a first panel portion 24a1 and a second panel portion 24a2. The second panel portion 24a2 is mounted on the first panel portion 24a1. Figure 3 As shown, the second panel portion 24a2 can be located on the left side of the front panel 24a.

[0060] In this example, the first panel portion 24a1 provides piping connections. Specifically, the discharge port 30, suction port 31, cooling medium inlet 44, and cooling medium outlet 45 are located on the first panel portion 24a1. The discharge port 30 and suction port 31 are positioned at the upper part of the first panel portion 24a1, while the cooling medium inlet 44 and cooling medium outlet 45 are positioned at the lower part of the first panel portion 24a1. Thus, the inlet and outlet of fluids such as refrigerant gas in the compressor 12 are concentrated in the first panel portion 24a1. No such fluid inlet and outlet are provided on the second panel portion 24a2.

[0061] Considering the operability of connecting the high-pressure piping 42 and the low-pressure piping 43 to the discharge port 30 and the suction port 31 respectively, the discharge port 30 and the suction port 31 are configured as follows: the distance between the centers of the discharge port 30 and the suction port 31 is, for example, an interval of 5cm to 20cm.

[0062] The cooling medium inlet 44 and the cooling medium outlet 45 are in the height direction ( Figure 3 It is positioned lower than the input power connector 51 and the communication cable connector 52 in the vertical direction.

[0063] Furthermore, a communication cable connector 52 is provided on the first panel portion 24a1. The communication cable connector 52 is connected to an external device via a communication cable, thereby enabling communication between the compressor 12 and the external device. The communication cable connector 52 is positioned on the first panel portion 24a1 above the discharge port 30 and the suction port 31.

[0064] Furthermore, the second panel portion 24a2 provides a power connection. An input power connector 51, a cold head connector 53, and a main switch 54 are located on the second panel portion 24a2. The input power connector 51 connects to an external power source, such as a commercial power supply, thereby powering the cryogenic refrigerator 10. Electrical wiring is connected to the cold head connector 53 for powering and controlling the cold head 14. This electrical wiring establishes an electrical connection between the compressor 12 and the cold head 14. The main switch 54 is used to switch the cryogenic refrigerator 10 on and off. When the main switch 54 is on, the compressor 12 and the cold head 14 operate; when the main switch 54 is off, the compressor 12 and the cold head 14 stop operating. The cold head connector 53 is located on the upper part of the second panel portion 24a2, while the input power connector 51 and the main switch 54 are located on the lower part of the second panel portion 24a2.

[0065] like Figure 2 As shown, casters 26 can be installed on the bottom panel 24d to facilitate the movement or transport of the compressor 12. Four casters 26 can be respectively installed at the four corners of the bottom panel 24d.

[0066] Figure 4 This is a schematic top view showing the equipment configuration within the compressor unit of the cryogenic refrigerator according to the embodiment. Figure 4 The figure shows the top panel 24c removed from the compressor unit frame 24. Furthermore, for convenience, the piping connecting the components of the compressor 12 is omitted from the figures.

[0067] As described above, the compressor 12 includes a compressor body 16, a heat exchanger 22, an oil separator 34, an adsorber 35, a storage tank 36, and a control panel 50, all of which are housed within the compressor unit frame 24. The front panel 24a of the compressor unit frame 24 has a first panel portion 24a1 and a second panel portion 24a2.

[0068] like Figure 4As shown, the oil separator 34, the adsorber 35, and the storage tank 36 are disposed on the side panel 24e between the front panel 24a and the rear panel 24b. In other words, the oil separator 34, the adsorber 35, and the storage tank 36 are disposed between the first panel portion 24a1 of the front panel 24a and the rear panel 24b. Furthermore, the compressor body 16 and the control panel 50 are disposed on the side panel 24f between the front panel 24a and the rear panel 24b. The compressor body 16 and the control panel 50 are disposed between the second panel portion 24a2 of the front panel 24a and the rear panel 24b.

[0069] The control panel 50 is mounted on the second panel portion 24a2 of the front panel 24a and is supported by the compressor unit frame 24. The control panel 50 may also be mounted on the side panel 24f. The compressor body 16, oil separator 34, adsorber 35 and storage tank 36 are disposed on the bottom panel 24d and are supported by the compressor unit frame 24.

[0070] The heat exchanger 22 is positioned near the rear panel 24b. The heat exchanger 22 is positioned along the rear panel 24b behind the compressor body 16 and the oil separator 34. Alternatively, as another configuration example, the heat exchanger 22 can be configured to surround components of the compressor 12, such as the storage tank 36, which are housed within the compressor unit frame 24. For example, the heat exchanger 22 can be wound around the storage tank 36.

[0071] Figure 5 This is a block diagram that schematically represents the control panel of the compressor unit involved in the embodiment. The control panel 50 is equipped with a frequency converter 60, a transformer 62, a noise filter 64, a DC reactor 66, a switching power supply 68, and a controller 70.

[0072] The inverter 60 converts the AC power input from an external power source into the compressor 12 into a drive power source for the compressor motor 28. As described above, the external power source is connected to the input power connector 51. The inverter 60 converts the AC power input from the input power connector 51 into AC power with a voltage and frequency suitable for driving the compressor motor 28. The frequency can be selected, for example, from the range of 30Hz to 78Hz. The inverter 60 can be used to adjust the speed of the compressor motor 28, thereby improving the energy efficiency of the compressor 12.

[0073] To reduce high-frequency noise in inverter 60, a noise filter 64 can be connected to inverter 60. The noise filter 64 is connected between the input power connector 51 and inverter 60. Furthermore, to suppress harmonic currents in inverter 60, a DC reactor 66 can also be connected to inverter 60.

[0074] Transformer 62 converts the AC power input from an external power source to the compressor 12 into a driving power source for the cold head 14. As described above, the cold head 14 is connected to the cold head connector 53. Depending on the country or region using the cryogenic refrigeration unit, the AC power input to the compressor 12 can have different voltages (e.g., any of several voltage values ​​in the range of 380V to 480V). Transformer 62 is capable of converting the AC power input from the input power connector 51 into AC power with a voltage suitable for driving the cold head 14 (e.g., 200V). Transformer 62 is also referred to as a voltage conversion transformer. By incorporating transformer 62, the compressor 12 can be used as a power source for the cold head 14. Furthermore, transformer 62 also helps to insulate the cold head 14 from power supply noise.

[0075] The switching power supply 68 converts the alternating current (AC) input to the compressor 12 from the external power source into direct current (DC). For example... Figure 5 As shown, the switching power supply 68 can be connected between the transformer 62 and the controller 70. The switching power supply 68 can convert the AC power output from the transformer 62 into DC power and supply the DC power to the controller 70.

[0076] In this embodiment, the switching power supply 68 and the transformer 62 are separate components. Alternating current (AC) is output from the transformer 62, and direct current (DC) is output from the switching power supply 68. The switching power supply 68 can be separately configured on the control panel 50 from the transformer 62. Therefore, compared to using a transformer capable of outputting both AC and DC, the transformer 62 can internally ensure insulation distance, thereby improving insulation performance.

[0077] The controller 70 can accept the outputs from various sensors such as the pressure sensor and temperature sensor installed on the cryogenic refrigerator 10, and control the frequency converter 60 according to the sensor outputs.

[0078] Figure 6 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment. Figure 6 The side panel 24f of the compressor unit frame 24 is shown. Furthermore, for ease of understanding, in Figure 6 In the diagram, the control panel 50, located on the inner side of the side panel 24f, is indicated by a dashed line.

[0079] like Figure 6As shown, the compressor unit housing 24 includes a housing inlet 72 and a housing outlet 74. The housing inlet 72 is the inlet for cooling air from the surrounding environment to the compressor 12, and the housing outlet 74 is the outlet for cooling air from the compressor 12 to the surrounding environment. The components of the compressor 12 housed within the compressor unit housing 24 are cooled by the air entering the compressor unit housing 24 through the housing inlet 72. The air heated by cooling the compressor 12 is discharged to the outside of the compressor 12 through the housing outlet 74.

[0080] The frame inlet 72 is positioned lower than the frame outlet 74. Therefore, by utilizing the natural convection of air heated as the compressor 12 cools, an airflow from the frame inlet 72 to the frame outlet 74 can be generated, effectively cooling the compressor 12. In this example, the frame inlet 72 and the frame outlet 74 are located on the side panel 24f of the compressor unit frame 24. The frame inlet 72 and the frame outlet 74 are positioned on the side panel 24f close to the front panel 24a.

[0081] The frame inlet 72 is formed on the lower part of the side panel 24f, and the frame exhaust port 74 is formed on the upper part of the side panel 24f. As described above, the control panel 50 is disposed adjacent to the side panel 24f within the compressor unit frame 24. Therefore, the frame inlet 72 is adjacent to the lower part of the control panel 50, and the frame exhaust port 74 is adjacent to the upper part of the control panel 50.

[0082] Figure 7 This is a diagram that schematically illustrates the equipment configuration on the control panel of the compressor unit involved in the embodiment. Figure 7 The diagram shows the configuration of the equipment on the control panel 50 when viewed from the front with the front panel 24a removed from the compressor unit housing 24, and the flow of cooling air is indicated by arrows for ease of understanding.

[0083] As described above, the control panel 50 is equipped with a frequency converter 60, a transformer 62, a noise filter 64, a DC reactor 66, a switching power supply 68, and a controller 70.

[0084] In this embodiment, transformer 62 is positioned lower than inverter 60. Noise filter 64 and DC reactor 66 are positioned lower than inverter 60 and higher than transformer 62. Therefore, among inverter 60, transformer 62, noise filter 64, and DC reactor 66, inverter 60 is positioned at the highest point on control panel 50. Among inverter 60, transformer 62, noise filter 64, and DC reactor 66, transformer 62 is positioned at the lowest point on control panel 50. Switching power supply 68 and controller 70 are positioned next to inverter 60, i.e., at the same height as inverter 60.

[0085] The inverter 60 includes an inverter housing 60a and an inverter circuit 60b, with the inverter circuit 60b housed within the inverter housing 60a. The inverter circuit 60b operates by converting alternating current input from an external power source into the compressor 12 into drive power for the compressor motor 28.

[0086] The inverter housing 60a has an inverter air inlet 76 and an inverter exhaust port 78. The inverter air inlet 76 is the inlet for cooling air from the control panel 50 to the inverter 60, and the inverter exhaust port 78 is the outlet for cooling air from the inverter 60 to the control panel 50.

[0087] The inverter air inlet 76 is positioned lower than the inverter exhaust outlet 78. As shown in the attached diagram, the inverter air inlet 76 is located at the lower part of the inverter housing 60a, and the inverter exhaust outlet 78 is located at the upper part of the inverter housing 60a. Therefore, the inverter air inlet 76 is positioned higher than the transformer 62, noise filter 64, and DC reactor 66. The inverter exhaust outlet 78 is positioned higher than the transformer 62, noise filter 64, DC reactor 66, switching power supply 68, and controller 70.

[0088] Furthermore, the control panel 50 includes an exhaust passage 80 that defines the flow path of cooling air from the inverter exhaust port 78 to the frame exhaust port 74. The exhaust passage 80 is mounted on the control panel 50 above the inverter 60. Therefore, the exhaust passage 80 is located at the top of the control panel 50. The exhaust passage 80 has a passage inlet adjacent to the inverter exhaust port 78 and a passage outlet adjacent to the frame exhaust port 74.

[0089] As described above, the frame air inlet 72 is positioned lower than the frame exhaust outlet 74, and the transformer 62 is positioned lower than the frequency converter 60. Therefore, compared to the transformer 62, the frequency converter 60 is positioned closer to the frame exhaust outlet 74. Compared to the frequency converter 60, the transformer 62 is positioned closer to the frame air inlet 72. The frame air inlet 72 is adjacent to the transformer 62, which is located at the lower part of the control panel 50.

[0090] Therefore, as Figure 7 As shown by the dashed arrow, cooling air enters the control panel 50 inside the compressor unit frame 24 from outside the compressor 12 through the frame inlet 72 and first cools the transformer 62. The cooled air then rises within the control panel 50, cooling the noise filter 64 and the DC reactor 66. Furthermore, the cooling air rises further and enters the inverter frame 60a from the inverter inlet 76, cooling the inverter circuit 60b. The air that has cooled the inverter 60 then flows out of the inverter frame 60a from the inverter exhaust port 78 and into the exhaust passage 80 from the passage inlet. Within the exhaust passage 80, the airflow is guided to the passage outlet and discharged from the frame exhaust port 74 to the outside of the compressor 12.

[0091] In this embodiment, the inverter 60 generates significantly more heat during operation compared to the equipment on the control panel 50, such as the transformer 62, noise filter 64, DC reactor 66, switching power supply 68, and controller 70. The air passing through and cooling the inverter 60 may reach temperatures as high as, for example, 50°C. When this high-temperature air from the inverter 60 comes into contact with other equipment, it may not cool that equipment; instead, it may heat it. However, according to this embodiment, the inverter 60 is positioned downstream of the cooling airflow, and the air cooling the inverter 60 is directly discharged from the housing exhaust port 74 to the outside of the compressor 12. Therefore, the problem that the high-temperature air from the inverter 60 might hinder the cooling of other equipment can be avoided.

[0092] Furthermore, since the exhaust passage 80 defines the flow path of cooling air from the inverter exhaust port 78 to the housing exhaust port 74, air from the inverter 60 is guided to the outside of the compressor 12 through the exhaust passage 80. The exhaust passage 80 helps prevent high-temperature air output from the inverter 60 from leaking into the control panel 50.

[0093] Assume that the heat generated by transformer 62 is second only to that of inverter 60. Transformer 62 is adjacent to the air inlet 72 of the housing, thus it can be effectively cooled by fresh air from the air inlet 72. Furthermore, since transformer 62 is heavy, its placement below the control panel 50 lowers the center of gravity of compressor 12, thereby improving stability.

[0094] In this embodiment, the space occupied by the compressor 12 falls within an area with a width of 600 mm or less and a length of 500 mm or less. Here, as... Figure 2As shown, the width of the space occupied by the compressor 12 corresponds to the width W of the compressor unit frame 24. The length of the space occupied by the compressor 12 corresponds to the length L of the compressor unit frame 24. In this way, the space occupied by the compressor 12 can be set to be the same as that of the compressor used in conventional cryogenic refrigeration machines.

[0095] Furthermore, the height H of the compressor 12 can be less than 700mm. In this way, when the heat exchanger 22 of the compressor 12 is water-cooled, the height H of the compressor 12 can be set to be the same as that of the compressor used in conventional cryogenic refrigeration machines.

[0096] The present invention has been described above with reference to the embodiments. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments, and various design changes and modifications are possible, and such modifications are also within the scope of the present invention. Various features described in one embodiment can also be applied to other embodiments. New embodiments resulting from combinations possess the effects of the combined embodiments.

[0097] In the above embodiment, the case where the compressor 12 has a water-cooled heat exchanger 22 was described as an example, but as... Figure 8 As shown, the compressor 12 may also be equipped with an air-cooled heat exchanger 90, either together with or in place of the water-cooled heat exchanger 22. The air-cooled heat exchanger 90 may be mounted on the compressor unit frame 24. In this case, the height H of the compressor 12 may be less than 1000 mm. In this way, the height H of the compressor 12 can be set to be the same as that of compressors used in conventional cryogenic refrigeration machines.

[0098] Figure 9 This is a diagram showing the equipment configuration on the control panel 50 of the compressor unit involved in the embodiment. Figure 9 It shows Figure 7 The schematic internal structure of the inverter 60 and exhaust passage 80 on the control panel 50 is shown.

[0099] To effectively cool the frequency converter 60, an air-cooled fan 60c can be installed on the control panel 50. The air-cooled fan 60c is mounted on the frequency converter 60 to generate airflow within the frequency converter housing 60a for cooling the frequency converter circuitry 60b. For ease of understanding, [the following is a more detailed explanation:] ... Figure 7 Similarly, in Figure 9 Arrows are used to indicate the flow of cooling air within the exhaust passage 80.

[0100] The air-cooled fan 60c can be configured inside the inverter housing 60a adjacent to the inverter exhaust port 78 of the inverter housing 60a, for example, it can be configured between the inverter circuit 60b and the inverter exhaust port 78 of the inverter housing 60a. Alternatively, the air-cooled fan 60c can also be mounted on the outer surface of the inverter housing 60a and configured between the inverter exhaust port 78 and the exhaust passage 80. The air-cooled fan 60c can also be a unit that can be detached from the inverter 60.

[0101] exist Figure 7 and Figure 9 In this example, the exhaust passage 80 is a single passage component. As described above, the exhaust passage 80 is mounted on the inverter housing 60a with its inlet side adjacent to the inverter exhaust port 78. Furthermore, the exhaust passage 80 is mounted on the side panel 24f with its outlet side adjacent to the housing exhaust port 74. Thus, the inverter exhaust port 78 is connected to the housing exhaust port 74 via the exhaust passage 80, and the air cooled by the inverter 60 is discharged from the housing exhaust port 74 to the outside of the compressor 12 through the exhaust passage 80.

[0102] To prevent high-temperature exhaust gas from the inverter exhaust port 74 from leaking into the control panel 50, the inlet of the exhaust channel 80 can be tightly fitted to the inverter frame 60a. For example, the inlet of the exhaust channel 80 can be threaded onto the inverter frame 60a. Alternatively, the inlet of the exhaust channel 80 can be installed onto the inverter frame 60a using adhesive tape such as aluminum tape. Alternatively, a sealing material such as rubber can be sandwiched between the inlet of the exhaust channel 80 and the inverter frame 60a. Similarly, to prevent high-temperature exhaust gas from the outlet of the exhaust channel 80 from leaking into the control panel 50, the outlet of the exhaust channel 80 can be tightly fitted to the side panel 24f. For example, the outlet of the exhaust channel 80 can be threaded onto the side panel 24f.

[0103] The air-cooled fan 60c in the various devices mounted on the control panel 50 is more prone to malfunctions such as unstable rotation of the drive motor, which occur with prolonged use, compared to other electrical components. In the event of a malfunction, maintenance work such as replacement or repair of the air-cooled fan 60c is performed. Typically, the frame panels, such as the side panel 24f, which constitute the compressor unit frame 24, have a bend 82 at at least one edge (the upper edge in the illustrated example) to improve structural strength or for mounting on other panels. The bend 82 is positioned above the mounting portion, acting like an eaves covering and concealing the mounting portion of the exhaust passage 80 on the side panel 24f.

[0104] When accessing the air-cooled fan 60c for maintenance, the top panel 24c must first be removed and the exhaust passage 80 taken out. However, if the outlet of the exhaust passage 80 is covered and hidden by the bend 82, the mounting portion is difficult to access even after the operator removes the top panel 24c, making it difficult to remove the exhaust passage 80 from the side panel 24f. Furthermore, even if one tries to remove the exhaust passage 80 upwards, the outlet of the exhaust passage 80 may interfere with the bend 82, making it impossible to remove the exhaust passage 80. With various components densely arranged inside the compressor unit housing 24, interference not only occurs with the bend 82 but also with these components, making the disassembly of the exhaust passage 80 even more difficult.

[0105] To address this issue, one approach could be to remove the control panel 50 itself from the compressor unit housing 24, then disconnect the exhaust passage 80 from the control panel 50 and access the air-cooled fan 60c. However, such a large-scale disassembly of the compressor 12 would complicate maintenance and increase working hours, making it an undesirable option.

[0106] Therefore, as described below, in order to improve maintainability, the exhaust channel 80 can be composed of multiple channel components.

[0107] Figure 10 This is a schematic diagram illustrating another example of an exhaust passage 80 mounted on a control panel 50 according to an embodiment. The exhaust passage 80 includes a passage inlet component 80a and a passage outlet component 80b. The passage inlet component 80a is mounted adjacent to the inverter exhaust port 78 on the inverter housing 60a. The passage inlet component 80a can be detached from the passage outlet component 80b and the inverter 60. For example, the passage inlet component 80a can be detachably mounted to the passage outlet component 80b by means of a threaded fastener. The passage outlet component 80b is mounted adjacent to the housing exhaust port 74 on the side panel 24g.

[0108] The channel inlet component 80a can be a cover that covers the end of the channel outlet component 80b, which is opposite to the exhaust port 74 of the frame, and the inverter exhaust port 78. Through Figure 9 and Figure 10 The comparison shows that the length of the channel inlet component 80a in the channel length direction is greater than that of the channel entrance component 80a. Figure 9 The exhaust passage 80 (a single passage component) is short. Here, the passage length direction refers to the extending direction of the exhaust passage 80 (left-right direction in the figure). The passage length direction corresponds to the extending direction from the bend 82 of the side panel 24f.

[0109] The length of the channel inlet component 80a in the channel length direction is determined as follows: when the channel inlet component 80a is installed on the channel outlet component 80b, the end of the channel inlet component 80a on the channel outlet component 80b side does not overlap with the bend 82. That is, the channel inlet component 80a is not covered and hidden by the bend 82.

[0110] The channel outlet component 80b may be a (e.g., rectangular) cylinder extending from the side panel 24f along the length of the channel. The length of the channel outlet component 80b in this direction is greater than... Figure 9 The exhaust passage 80 (a single passage component) is short. To facilitate the installation of the passage inlet component 80a onto the passage outlet component 80b and to facilitate the removal of the passage inlet component 80a from the passage outlet component 80b, as shown in the figure, the length of the passage outlet component 80b can be longer than the length of the bend 82. Furthermore, to prevent the passage outlet component 80b from blocking the inverter exhaust port 78, the length of the passage outlet component 80b can be determined so that it does not overlap with the inverter exhaust port 78.

[0111] Therefore, the inverter exhaust port 78 is connected to the frame exhaust port 74 via the channel inlet component 80a and the channel outlet component 80b, and the air that has cooled the inverter 60 is discharged from the frame exhaust port 74 through the exhaust channel 80 to the outside of the compressor. Figure 10 In the example shown, it is also related to Figure 9 Similarly, in the example shown, to prevent the high-temperature exhaust gas from the inverter exhaust port 78 from leaking into the control panel 50, the channel inlet component 80a can be attached tightly to the inverter frame 60. Furthermore, the channel outlet component 80b can be attached tightly to the side panel 24f.

[0112] To maintain the air-cooled fan 60c, first remove the top panel 24c. Next, remove the channel inlet component 80a from the channel outlet component 80b and the inverter 60. Figure 9 The examples are different, in Figure 10 In the example shown, the channel entrance component 80a is not covered and hidden by the bend 80. Therefore, as... Figure 10 As indicated by the upward-pointing arrow, the channel inlet component 80a can be removed upwards without interfering with the bending portion 82. Thus, it is possible to... Figure 9 The single-channel component makes it easier to remove the channel inlet component 80a. Although the channel outlet component 80b remains on the side panel 24f, removing the channel inlet component 80a ensures sufficient space for accessing the air-cooled fan 60c. Therefore, the maintainability of the air-cooled fan 60c is improved.

[0113] In the above embodiment, the case where the frame inlet 72 and frame outlet 74 are provided on the side panel 24f of the compressor unit frame 24 is illustrated. However, the frame inlet 72 and frame outlet 74 can also be provided on other panels of the compressor unit frame 24. For example, the frame inlet 72 and frame outlet 74 can also be provided on the front panel 24a. In this case, similarly to the above embodiment, the control panel 50 can also have an exhaust passage 80 that defines the flow path of cooling air from the inverter outlet 78 to the frame outlet 74. The exhaust passage 80 can be a single passage component or it can have multiple passage components.

[0114] The present invention has been described above according to the embodiments and using specific terminology. However, the embodiments only show one aspect of the principle and application of the present invention. In the embodiments, various modifications and configuration changes are allowed without departing from the spirit of the present invention as specified in the technical solution.

Claims

1. A compressor unit, which is a compressor unit of an ultra-low temperature refrigerating machine, characterized by, Possessing: a compressor motor; an inverter that converts alternating current input from an external power source into a driving power source for the compressor motor; a transformer that converts the alternating current into a driving power source for a cold head of the ultra-low temperature refrigerator having a voltage different from that of the alternating current; and a control panel on which the inverter and the transformer are mounted.

2. The compressor unit according to claim 1, wherein the inverter has an inverter exhaust port that becomes an outlet for cooling air from the inverter, and the inverter is mounted on the control panel in such a manner that the inverter exhaust port is located higher than the transformer.

3. The compressor unit according to claim 1, wherein the transformer is disposed lower than the inverter.

4. The compressor unit according to any one of claims 1 to 3, further comprising a switching power source that converts the alternating current into direct current, wherein the control panel has the switching power source mounted thereon.

5. The compressor unit according to claim 4, wherein the inverter has an inverter exhaust port that becomes an outlet for cooling air from the inverter, and the inverter is mounted on the control panel in such a manner that the inverter exhaust port is located higher than the switching power source.

6. The compressor unit according to any one of claims 1 to 3, further comprising a noise filter and a direct current reactor connected to the inverter, wherein the control panel has the noise filter and the direct current reactor mounted thereon.

7. The compressor unit according to claim 6, wherein the inverter has an inverter exhaust port that becomes an outlet for cooling air from the inverter, and the inverter is mounted on the control panel in such a manner that the inverter exhaust port is located higher than the noise filter and the direct current reactor.

8. The compressor unit according to claim 6, wherein the noise filter and the direct current reactor are disposed lower than the inverter and higher than the transformer.

9. The compressor unit according to any one of claims 1 to 3, wherein the inverter has an inverter exhaust port that becomes an outlet for cooling air from the inverter, and the compressor unit further comprises a compressor unit housing that has a housing exhaust port that becomes an outlet for the cooling air from the compressor unit and accommodates the compressor motor and the control panel, and the control panel has an exhaust passage that defines a flow path of the cooling air from the inverter exhaust port to the housing exhaust port.

10. The compressor unit according to claim 9, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The compressor unit frame has a frame air inlet configured at a position lower than the frame air outlet and serving as an entrance for the cooling air to the compressor unit.

11. The compressor unit according to claim 10, wherein The frequency converter is configured closer to the frame air outlet than the transformer, The transformer is configured closer to the frame air inlet than the frequency converter.

12. The compressor unit according to claim 9, wherein The exhaust passage has a passage inlet member adjacent to the frequency converter air outlet and a passage outlet member adjacent to the frame air outlet, and the passage inlet member is detachable from the passage outlet member and the frequency converter.

13. The compressor unit according to any one of claims 1 to 3, wherein The compressor unit occupies a space falling within a region having a width of 600 mm or less and a length of 500 mm or less.

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