Compressor for cryogenic refrigerator and compressor housing for cryogenic refrigerator

Abstract

The present invention addresses the problem of efficiently cooling a compressor for a cryogenic refrigerator. A compressor (12) for a cryogenic refrigerator (10) is provided with: a compressor housing (24) having an air inlet (50) on a surface different from a front surface (24a) of the compressor housing (24), and having an air inlet (52) for the air inlet (50) on an edge of the front surface (24a); and an air flow generator (29) that is disposed inside the compressor housing (24) and that generates an air flow into the compressor housing (24) from the air inlet (52) via the air inlet (50). The compressor housing (24) may have an air inlet (50) in a bottom surface (24d) of the compressor housing (24) opposite the compressor setting surface (26), and an air inlet (52) between the compressor setting surface (26) and a lower edge of the front surface (24a).

Description

[0001] This application claims priority based on Japanese Patent Application No. 2024-185342, filed on October 21, 2024. The entire contents of that Japanese application are incorporated herein by reference. Technical Field

[0002] The present invention relates to a compressor for an ultra-low temperature refrigeration machine and a compressor housing for an ultra-low temperature refrigeration machine. Background Technology

[0003] Cryogenic cryogenic refrigerators can be used for cryogenic cooling of measuring elements in various fields such as superconducting single-photon detectors, gravitational wave detectors, and voltage standards. In this case, the cryogenic refrigerator has a cold head for cooling the measuring elements and a compressor for supplying and discharging refrigerant gases such as helium to the cold head. The heat absorbed by the cold head is dissipated through the compressor.

[0004] Patent Document 1: Japanese Patent Publication No. 2019-505751

[0005] The measuring device described above may include multiple components such as a cryostat equipped with a cryogenic refrigerator, a power supply, a detector, and a vacuum pump. If each component requires space for installation, a considerable amount of space may be needed to set up the entire measuring device. Furthermore, installing and moving the measuring device requires a relatively strenuous task for operators, such as disconnecting and packaging electrical wires and gas pipes from each component, then unpacking the components on-site and reconnecting them with electrical wires and gas pipes. As one solution to this problem, the inventors propose integrating the components of the measuring device into a rack. By storing the components in the rack's storage compartment, the space occupied by the measuring device can be reduced. Moreover, transporting the measuring device along with the rack facilitates installation and relocation.

[0006] However, the inventors recognized that in such a measuring device, heat dissipation from the compressor of the cryogenic refrigerator could be limited. This is because, in addition to needing to be miniaturized to fit within a frame, the compressor is also surrounded by a housing such as the frame walls or base plate, which can hinder heat dissipation. In particular, in the case of an air-cooled compressor, the direction or location of intake and exhaust is restricted, which may significantly affect the heat dissipation capacity. A reduction in the compressor's heat dissipation capacity may lead to a decrease in the performance and lifespan of the cryogenic refrigerator, and therefore this is undesirable. Summary of the Invention

[0007] One of the exemplary objectives of one embodiment of the present invention is to efficiently cool the compressor used in a cryogenic refrigeration machine.

[0008] According to one embodiment of the present invention, a compressor for a cryogenic refrigeration machine comprises: a compressor housing having an air inlet on a surface different from the front surface of the compressor housing, and an air inlet for the air inlet at the edge of the front surface; and an airflow generator disposed within the compressor housing for generating an airflow from the air inlet through the air inlet into the compressor housing.

[0009] According to one embodiment of the present invention, a compressor for a cryogenic refrigeration machine includes: a compressor housing; and a compressor component disposed within the compressor housing, which generates vibration and / or heat during operation. The compressor housing includes a support plate that supports the compressor component and is supported on the bottom surface of the compressor housing via a vibration damper. The vibration damper is disposed outside the support plate when viewed from above.

[0010] According to one embodiment of the present invention, a compressor housing for an ultra-low temperature refrigeration machine includes: a front surface; and a surface different from the front surface having an air inlet, and an air intake for the air inlet having an edge of the front surface.

[0011] Invention Effects

[0012] According to the present invention, compressors used in cryogenic refrigerators can be cooled efficiently. Attached Figure Description

[0013] Figure 1 This is a diagram that schematically illustrates the cryogenic refrigerator involved in the embodiment.

[0014] Figure 2 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0015] Figure 3 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0016] Figure 4 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0017] Figure 5 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0018] Figure 6 This is a schematic diagram showing the interior of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0019] Figure 7 This is a schematic diagram showing the interior of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0020] Figure 8 This is a schematic diagram showing the interior of the compressor unit of the cryogenic refrigerator involved in the embodiment.

[0021] In the diagram: 10-Cryogenic refrigerator, 12-Compressor, 24-Compressor housing, 24a-Front surface, 24b-Rear surface, 24c-Upper surface, 24d-Bottom surface, 26-Compressor mounting surface, 29-Airflow generator, 50-Inlet, 52-Air inlet, 54-Exhaust port, 62-Guide, 64-Direct-acting mechanism, 70-Transformer, 70a-Exhaust inlet, 72-Support plate, 74-Vibration damper, 76-Fixing component. Detailed Implementation

[0022] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the specification and drawings, the same or equivalent constituent elements, components, and processes are labeled with the same symbols, and repeated descriptions are omitted where appropriate. The proportions or shapes of the illustrated parts are provided for ease of explanation and should not be interpreted as limiting unless specifically mentioned. The embodiments are illustrative and do not limit the scope of the invention in any way. All features or combinations thereof described in the embodiments are not necessarily essential to the invention.

[0023] Figure 1 This 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 measuring device. The measuring device can be, for example, a measuring device in various fields such as a superconducting single-photon detector, a gravitational wave detector, or a voltage standard.

[0024] 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 resupply it 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 it has a room temperature section 14a and a cryogenic section 14b (also referred to as a cooling platform). The refrigerant gas is also referred to as the working gas, which is 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 in a measuring device, such as measuring elements.

[0025] 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 different structures depending on the type of cryogenic refrigerator 10, but as for the compressor 12, regardless of the type of cryogenic refrigerator 10, the structure described below can be used.

[0026] 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; these 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 high pressure and low pressure, respectively. Typically, the high pressure is, for example, 2–3 MPa. The low pressure is, for example, 0.5–1.5 MPa, for example, about 0.8 MPa.

[0027] 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. Figure 1 In the diagram, for ease of understanding, the refrigerant gas line 18 is shown in solid lines, and the oil circulation line 20 is shown in dashed lines. Furthermore, the compressor 12 includes a compressor housing 24 that houses the compressor body 16, the refrigerant gas line 18, the oil circulation line 20, and other components of the compressor 12.

[0028] The compressor body 16 is configured such that refrigerant gas drawn in through its suction port is compressed internally and then discharged 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.

[0029] The compressor body 16 may be, for example, a scroll pump, a rotary pump, or other pump that pressurizes the refrigerant gas. The compressor body 16 may be configured to discharge a fixed, 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.

[0030] 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 a refrigerant gas outlet located on the compressor housing 24 for delivering refrigerant gas pressurized to high pressure by the compressor body 16 from the compressor 12. The suction port 31 is a refrigerant gas inlet located on the compressor housing 24 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 housing 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.

[0031] 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 through the high-pressure piping 42, and the low-pressure port 41 is connected to the suction port 31 through the low-pressure piping 43.

[0032] An oil separator 34 and an adsorber 35 are provided on the discharge flow path 32. The oil separator 34 is provided to separate oil from the refrigerant gas that has been mixed into the refrigerant gas through the compressor body 16. The adsorber 35 is provided 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 disposed on the compressor body 16 side, and the adsorber 35 is disposed on the discharge port 30 side.

[0033] On the other hand, a storage tank 36 is provided on the suction flow path 33. The storage tank 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.

[0034] Furthermore, a bypass valve 38 is provided on the refrigerant gas line 18, which connects the discharge path 32 and the suction path 33 by bypassing the compressor body 16. As an example, the bypass valve 38 branches off from the discharge path 32 between the oil separator 34 and the adsorber 35, and connects to the suction path 33 between the compressor body 16 and the storage tank 36. The bypass valve 38 is provided to control the refrigerant gas flow rate and / or to equalize the pressure between the discharge path 32 and the suction path 33 when the compressor 12 is stopped.

[0035] The oil circulation line 20 connects the oil outlet and oil inlet of the compressor body 16, allowing oil flowing out of the compressor body 16 to return to the compressor body 16. A throttling orifice for controlling the flow rate of oil through the oil circulation line 20 can be provided. Furthermore, a filter for removing dust contained in the oil can be provided on the oil circulation line 20.

[0036] Furthermore, an oil return line 21 is provided to connect 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 provided midway through the oil return line 21.

[0037] Furthermore, the compressor 12 includes a control panel 39. The control panel 39 is mounted on the compressor 12 as a control device for controlling the cryogenic refrigerator 10. The control panel 39 may include a control circuit configured to receive outputs from various sensors installed in 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 39 within the compressor housing 24. Each sensor can be connected to the control panel 39 via a communication cable. Electrical components controlled according to sensor outputs may include, for example, the compressor motor 17 driving the compressor body 16, a bypass valve 38, and a cold head motor driving the cold head 14.

[0038] In compressor 12, various sensors such as pressure sensors and temperature sensors can be installed to monitor the status of compressor 12. A first pressure sensor 37a can be configured in 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 39. A second pressure sensor 37b can be configured in 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 39. Temperature sensors may include: a refrigerant gas temperature sensor installed in the refrigerant gas line 18, an oil temperature sensor installed in the oil circulation line 20, and a cooling temperature sensor installed in the low-temperature section 14b of the cold head 14. The temperature sensor is configured to output a signal indicating the measured temperature to the control panel 39.

[0039] Figures 2 to 4 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment. Figure 2 The lower part of the front surface of the compressor 12 is shown in a simplified manner. Figure 3 The bottom surface of compressor 12 is roughly shown in the image. Figure 4 The image shows a simplified perspective view of the compressor 12 from below.

[0040] like Figures 2 to 4As shown, the compressor housing 24 has a cuboid shape with six faces: a front surface 24a, a rear surface 24b, an upper surface 24c, a bottom surface 24d, a left side surface 24e, and a right side surface 24f. The rear surface 24b faces the side opposite to the front surface 24a. Between the front surface 24a and the rear surface 24b, the upper surface 24c is positioned above, and the bottom surface 24d is positioned below. When viewed from the front surface 24a, the left side surface 24e and the right side surface 24f are positioned to the left and right, respectively. These faces of the compressor housing 24 can be sheet-like panel components made of stainless steel or other suitable materials.

[0041] The bottom surface 24d of the compressor housing 24 faces the compressor mounting surface 26. When the cryogenic refrigerator 10 is housed in a frame, the compressor mounting surface 26 can be a shelf surface of the frame. The frame can be, for example, a standard-sized frame, such as a 19-inch frame. Items being cooled, such as measuring devices, can be housed together with the cryogenic refrigerator 10 within the frame.

[0042] When the compressor 12 is housed in the frame, the upper surface 24c, bottom surface 24d, left side surface 24e, and right side surface 24f of the compressor housing 24 are covered by the shelves or walls of the frame. On the other hand, the front surface 24a and rear surface 24b of the compressor housing 24 are not covered by the shelves or walls of the frame and are easily accessible. Therefore, various user interfaces can be provided on the front surface 24a and rear surface 24b of the compressor housing 24.

[0043] For example, on the front surface 24a of the compressor housing 24, a display panel that displays information related to the cryogenic refrigerator 10, such as the running time of the cryogenic refrigerator 10, a pressure gauge that indicates the pressure of the refrigerant gas supplied from the compressor 12 to the cold head 14, a refrigerant gas replenishment port for replenishing refrigerant gas in the refrigerant gas pipeline 18, and the main switch of the cryogenic refrigerator 10 can be provided.

[0044] The rear surface 24b of the compressor housing 24 can provide piping and power connections. For example, the discharge port 30 and suction port 31 of the refrigerant gas line 18 can be provided on the rear surface 24b of the compressor housing 24. Furthermore, an input power connector, a cold head connector, and a communication cable connector can also be provided on the rear surface 24b of the compressor housing 24. The input power connector connects to an external power source such as a commercial power supply, thereby supplying power to the cryogenic refrigerator 10. The cold head connector is connected to wires for supplying power to the cold head 14 and for controlling the cold head 14. The communication cable connector connects to external devices via a communication cable, thereby enabling communication between the compressor 12 and external devices.

[0045] The compressor 12 also includes a compressor cooling system 28. In this embodiment, the compressor cooling system 28 is configured as an air-cooled heat exchanger and includes an airflow generator 29 housed in the compressor housing 24. The compressor cooling system 28 cools the compressor 12 by exchanging heat with compressor components such as the refrigerant gas line 18 and the oil circulation line 20 through an airflow generated by the airflow generator 29 within the compressor housing 24. The airflow generator 29 may be a cooling fan that forcibly cools the refrigerant gas line 18 and the oil circulation line 20 by means of airflow.

[0046] The airflow generator 29 can be configured to allow air to enter from outside the compressor housing 24 and blow air out onto the refrigerant gas line 18 and the oil circulation line 20, thereby cooling them. Alternatively, the airflow generator 29 can also be configured to cool the refrigerant gas line 18 and the oil circulation line 20 by drawing air around them to the outside of the compressor housing 24. To cool the high-pressure refrigerant gas heated by the heat of compression generated by the compressor body 16 compressing the refrigerant gas, the airflow generator 29 can be configured to cool the refrigerant gas line 18 between the compressor body 16 and the oil separator 34 on the discharge flow path 32.

[0047] like Figures 1 to 4 As shown, in this embodiment, the compressor housing 24 has an air inlet 50, an air intake 52 for the air inlet 50, and an exhaust port 54. An airflow generator 29 generates an airflow from the air intake 52 into the compressor housing 24 through the air intake 50. For ease of understanding, in... Figure 1 and Figure 4 Arrow 56 schematically illustrates the airflow flowing from the air inlet 52 into the compressor housing 24 through the air inlet 50. Furthermore, the airflow generator 29 discharges the airflow flowing from the air inlet 50 into the compressor housing 24 as exhaust air from the exhaust port 54 to the outside of the compressor housing 24. For ease of understanding, in... Figure 1 and Figure 4 In the image, arrow 58 schematically illustrates the exhaust airflow.

[0048] The air inlet 50 is located on a surface different from the front surface 24a of the compressor housing 24; in this example, it is located on the bottom surface 24d of the compressor housing 24. The air inlet 50 can be at least one opening penetrating the compressor housing 24, such as multiple slits or holes. The air inlet 50 can also be located in a specific area of ​​a particular surface of the compressor housing 24 (in this example, the bottom surface 24d), for example, in the area near the air inlet 52 (in this example, the area near the front surface 24a in the bottom surface 24d). Alternatively, the air inlet 50 can be located on the entire specific surface of the compressor housing 24. To form the air inlet 50, at least a portion of the specific surface of the compressor housing 24 (in this example, the bottom surface 24d) can be formed, for example, by a perforated plate such as a perforated metal sheet or a wire mesh.

[0049] An air inlet 52 is provided at the edge of the front surface 24a of the compressor housing 24, and in this example, at the lower edge of the front surface 24a. More specifically, the gap formed between the compressor mounting surface 26 and the lower edge of the front surface 24a functions as the air inlet 52.

[0050] From the viewpoint of reducing wind noise (described later), the total area of ​​the air inlet 52 (i.e., the sum of the areas of the air inlets 52 along the plane of the front surface 24a of the compressor housing 24) can be smaller than the total area of ​​the air inlet 50 (i.e., the sum of the areas of the air inlets 50 along the plane of the bottom surface 24d of the compressor housing 24). For example, the total area of ​​the air inlet 52 can be set to be more than 20% and less than 50% of the total area of ​​the air inlet 50, taking into account the balance between wind noise and airflow.

[0051] In order to form an air inlet 52 between the compressor mounting surface 26 and the lower edge of the front surface 24a, the compressor housing 24 may have a support 60 that slightly lifts the compressor 12 upward from the compressor mounting surface 26. The support 60 is provided on the bottom surface 24d of the compressor housing 24 and can support the compressor 12 on the compressor mounting surface 26.

[0052] The compressor housing 24 has at least one guide 62 that directs airflow from the air inlet 52 to the air inlet 50. The guide 62 is disposed on the bottom surface 24d of the compressor housing 24. The guide 62 may form part of the support 60.

[0053] In this example, three guides 62 extend linearly from the lower edge of the front surface 24a toward the lower edge of the rear surface 24b on the bottom surface 24d. Two guides 62 are positioned on either side of the bottom surface 24d, and the remaining guide 62 is positioned in the center of the bottom surface 24d. An air intake passage from the air inlet 52 to the air inlet 50 is formed between adjacent guides 62.

[0054] In addition, such as Figure 1 As shown, in order to separate dust from the airflow and prevent dust from entering the compressor 12, the filter 68 can be placed at any position in the intake passage.

[0055] like Figure 2 As shown, the guide member 62 can form part of a direct-acting mechanism 64 that supports the compressor 12 so that it can move relative to the compressor mounting surface 26. In the illustrated example, the two guide members 62 disposed on both sides of the bottom surface 24d are part of the direct-acting mechanism 64. The direct-acting mechanism 64 can be configured to allow the compressor 12 to move linearly relative to the compressor mounting surface 26 in the front-rear direction. The direct-acting mechanism 64 can be, for example, a slide rail having a fixed-side guide rail fixed to the compressor mounting surface 26, and the guide member 62 can be, for example, a movable-side guide rail fixed to the bottom surface 24d of the compressor housing 24 and movably supported on the fixed-side guide rail. In this way, when the compressor 12 is housed in the frame, it is advantageous to be able to easily remove and place the compressor 12 in the frame using the direct-acting mechanism 64.

[0056] The exhaust port 54 is located at a different location from the front surface 24a and bottom surface 24d of the compressor housing 24; in this example, it is located on the rear surface 24b of the compressor housing 24. The exhaust port 54 can be at least one opening penetrating the compressor housing 24, such as multiple slits or holes. The exhaust port 54 can be located in at least a portion of a specific surface of the compressor housing 24 (in this example, the rear surface 24b). To form the exhaust port 54, at least a portion of the specific surface of the compressor housing 24 can be formed, for example, by a perforated plate such as a perforated metal sheet or a wire mesh.

[0057] 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 refrigerant gas expansion space 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. In the case of a two-stage cold head 14, for example, 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, 1K to 20K. The second cooling temperature can be approximately 4.2K of liquid helium or a temperature lower than that.

[0058] 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 recovered to the suction port of the compressor body 16 via the storage tank 36 on the suction path 33. The refrigerant gas is compressed and pressurized by the compressor body 16. Refrigerant gas delivered from the discharge port of the compressor body 16 flows out of 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.

[0059] During operation of the cryogenic refrigerator 10, an airflow generator 29 operates, and an airflow (arrow 56) flows from the air inlet 52 into the compressor housing 24 via the inlet 50. The refrigerant gas and oil, heated by the compression heat of the compressor body 16, are cooled through heat exchange with the airflow. The refrigerant gas is cooled in the compressor cooling system 28 and supplied from the compressor 12 to the cold head 14. The oil is cooled in the compressor cooling system 28 and returns to the compressor body 16. The airflow, heated by heat exchange, is discharged as exhaust air (arrow 58) from the compressor housing 24 via the exhaust port 54. In this way, the compression heat generated in the compressor body 16 is discharged to the outside of the compressor 12 along with the airflow.

[0060] According to the embodiment, relatively low-temperature fresh air can be introduced into the compressor housing 24 from the space in front of the compressor 12 through the air inlet 52 and the air intake 50. This airflow can be used to promote heat dissipation of the compressor 12, thereby efficiently cooling the compressor 12. As a result, excessive heating of the compressor 12 caused by insufficient heat dissipation and the resulting reduction in the performance and lifespan of the cryogenic refrigerator can be suppressed.

[0061] This cooling structure is particularly advantageous when the compressor 12 is housed within a frame. Even when the compressor 12 is surrounded by the shelf surface or wall of the frame, the front surface 24a of the compressor 12 is typically open to the space in front of the compressor 12. The air inlet 52 on the front surface 24a draws in cool, fresh air from the space in front of the compressor 12, efficiently cooling the compressor 12.

[0062] Furthermore, the configuration of the air inlet 50 and air intake 52 involved in the embodiment is also effective in reducing noise generated by the airflow. In typical conventional compressors, an air inlet (multiple slits, openings, etc.) can be formed on the front surface of the housing to allow a large amount of air to enter. In this case, the air inlet can become a source of wind noise generated by the air passing through it. The generated wind noise easily propagates from the front surface of the housing to the surrounding space, which can be perceived as noise. However, in the embodiment, the air inlet 50 is not provided on the front surface 24a of the compressor housing 24. The air inlet 50 is opposite to the compressor mounting surface 26. The compressor mounting surface 26 acts as a barrier, so even if wind noise is generated from the air inlet 50, it is not easy to propagate to the surroundings. Therefore, noise is reduced, and the quietness of the compressor 12 can be improved.

[0063] And, as Figure 3 and Figure 4 As shown, the surface of the compressor housing 24 where the air inlet 50 is located (in this example, the bottom surface 24d of the compressor housing 24) is configured to prevent exhaust air from flowing into the air inlet 50. Therefore, a shielding member 66 is provided. The shielding member 66 is configured to block the gap between the surface of the compressor housing 24 where the air inlet 50 is located and the surface opposite to it (in this example, the gap between the bottom surface 24d and the compressor mounting surface 26).

[0064] The shielding member 66 is disposed on the side of the bottom surface 24d opposite to the air inlet 50 and the air intake 52. The shielding member 66 is disposed on the edge of the rear surface 24b of the compressor housing 24, in this example, on the lower edge of the rear surface 24b. The shielding member 66 may be a shielding plate disposed at the rear end of the guide 62 to connect the guide 62.

[0065] The exhaust air exiting from exhaust port 54 absorbs the heat discharged from compressor 12, therefore its temperature is higher than the temperature of the airflow drawn in from intake port 50. By using shielding component 66 to prevent exhaust air from flowing into intake port 50, the temperature rise caused by exhaust air mixing with intake air can be suppressed. This also contributes to the efficient cooling of compressor 12.

[0066] Figure 5 This is a diagram that schematically shows the appearance of the compressor unit of the cryogenic refrigerator involved in the embodiment. Figure 5 The figure shows a schematic perspective view of the compressor 12 from the rear. As shown, the compressor 12 may include a transformer 70. The compressor 12 may be connected to an external power source via the transformer 70. The transformer 70 may be configured to convert power (e.g., voltage) from the external power source into power suitable for the compressor 12 and supply it to the compressor 12. The transformer 70 may be detachably mounted to the compressor housing 24.

[0067] The transformer 70 is positioned on the outside of the compressor housing 24 near the exhaust port 54. The transformer 70 can be mounted on the compressor housing 24 (e.g., on the rear surface 24b of the compressor housing 24) adjacent to the exhaust port 54. In the illustrated example, the transformer 70 is positioned on one side of the rear surface 24b of the compressor housing 24 (left side in the figure), and the exhaust port 54 is located on the other side of the rear surface 24b (right side in the figure). This offsets the transformer 70 from the exhaust port 54 to avoid obstructing the flow of exhaust air exiting the exhaust port 54.

[0068] During the operation of the cryogenic refrigerator 10, the transformer 70 generates a large amount of heat, potentially reaching a relatively high temperature. The inventors discovered that the temperature of the transformer 70 may exceed the temperature of the exhaust air; therefore, the exhaust air can be used to cool the transformer 70. By actively cooling the transformer 70 with exhaust air, the temperature rise of the transformer 70 can be suppressed. This, in turn, can suppress the deterioration of the insulation within the transformer 70, thereby extending the lifespan of the transformer 70.

[0069] To facilitate cooling of the transformer 70, the transformer 70 may have an exhaust inlet 70a for drawing in exhaust air. As shown in the figure, to facilitate the entry of exhaust air, the exhaust inlet 70a may be located on the surface of the transformer 70 adjacent to the exhaust port 54. Furthermore, the transformer 70 may have an exhaust outlet 70b. The exhaust outlet 70b may be located on a different surface from the surface of the transformer 70 where the exhaust inlet 70a is located; in the illustrated example, it may be located on the rear surface of the transformer 70. The exhaust inlet 70a and the exhaust outlet 70b may each be at least one opening penetrating the casing of the transformer 70, for example, a plurality of slits or holes.

[0070] Additionally, the exhaust inlet 70a of the transformer 70 can be connected to the exhaust port 54 of the compressor 12. For example, the exhaust inlet 70a can be connected to the exhaust port 54 via a conduit. In this case, the transformer 70 can be configured to be opposite to the exhaust port 54.

[0071] Figures 6 to 8 This is a schematic diagram showing the interior of the compressor unit of the cryogenic refrigerator involved in the embodiment. Figure 6 The text roughly illustrates the basis of... Figure 3 A portion of the cross-section of line AA shown. Figure 7 The text roughly illustrates the basis of... Figure 6 A portion of the cross-section of the BB line shown. Figure 8 The text roughly illustrates the basis of... Figure 7 A portion of the cross-section of the CC line shown.

[0072] like Figure 6As shown, the compressor component, which is disposed within the compressor housing 24 and generates vibration and / or heat during operation, can be supported on the support plate 72. Such a compressor component may include, for example, the compressor body 16, airflow generator 29, control panel 39, and other components described above. Furthermore, in Figure 7 and Figure 8 For ease of understanding, the diagram of the compressor components has been omitted.

[0073] The support plate 72 is disposed within the compressor housing 24 opposite to the bottom surface 24d of the compressor housing 24. The compressor housing 24 may have a dual structure consisting of an outer housing and an inner housing, and the support plate 72 may form the bottom surface of the inner housing. The compressor components may be disposed within the inner housing, and the inner housing may be disposed within the outer housing. The outer housing may have the aforementioned front surface 24a, rear surface 24b, upper surface 24c, bottom surface 24d, left side surface 24e, and right side surface 24f.

[0074] The support plate 72 is supported on the bottom surface 24d of the compressor housing 24 via the anti-vibration seat 74. For example... Figure 7 As shown, the vibration damping seats 74 are positioned on the outer side of the support plate 72 when viewed from above. In this example, four vibration damping seats 74 are provided, positioned at the four corners of the bottom surface 24d. The support plate 72 is vibration-dampedly supported on the bottom surface 24d by the vibration damping seats 74, thereby suppressing the transmission of vibrations generated by the compressor components to the outside.

[0075] The compressor housing 24 has a fixing member 76 mounted on the outer periphery of the support plate 72, and the vibration damping seat 74 is fixed to the fixing member 76. In the illustrated example, a pair of elongated fixing plates are used as the fixing member 76. These fixing plates are fixed to two opposite sides of the support plate 72. Figure 8 As shown, the two sides of the support plate 72 can also be folded back, and the fixing piece can be fixed to the folded-back portion. The cross-section of the support plate 72 can be described as U-shaped. The folded-back portion also helps to improve the rigidity of the support plate 72.

[0076] like Figure 7 As shown, the length of the fixing plate is greater than the length of the side of the support plate 72 to which it is fixed, thus extending both ends of the fixing plate to both sides of the support plate 72. For each fixing plate, two vibration damping seats 74 are fixed to both ends of the fixing plate. Each vibration damping seat 74 is fixed to the fixing plate by means of vibration damping material such as vibration damping rubber sandwiched between the bottom surface 24d and the fixing plate, for example by bolts or other appropriate methods.

[0077] Since the compressor components are mounted on the support plate 72, the temperature tends to rise due to the heat generated by the compressor components. By clamping the fixing member 76 between the support plate 72 and the vibration damper 74, the fixing member 76 acts as a so-called thermal resistance. Therefore, compared to directly fixing the vibration damper 74 to the support plate 72, heat conduction from the support plate 72 to the vibration damper 74 can be reduced. The temperature rise of the vibration damper 74 can be suppressed, thereby suppressing the deterioration of the vibration damper 74 and extending its service life.

[0078] Furthermore, since the vibration damper 74 is positioned outside the support plate 72 when viewed from above, it can be positioned further away from the support plate 72 compared to positioning it directly below it. Moreover, the outer side of the support plate 72 is located in the gap between the outer and inner housings, thus serving as a passage for airflow from the intake port 50 into the compressor housing 24. This also helps to suppress temperature rise in the vibration damper 74.

[0079] The present invention has been described above with reference to the embodiments. The present invention is not limited to the embodiments described above. Those skilled in the art should understand that the present invention can be modified in various ways and various variations can exist, and such variations are also within the scope of the present invention. The various features described in association with one embodiment can also be applied to other embodiments. New embodiments resulting from combinations possess the effects of each of the combined embodiments.

[0080] In the above embodiment, an example is given where the air inlet 50 is provided on the bottom surface 24d of the compressor housing 24 and the air inlet 52 is provided on the lower edge of the front surface 24a of the compressor housing 24. However, the air inlet 50 and the air inlet 52 may also be provided in other parts of the compressor housing 24.

[0081] For example, the air inlet 50 can be located on the upper surface 24c of the compressor housing 24, and the air inlet 52 can be located on the upper edge of the front surface 24a of the compressor housing 24. Alternatively, the air inlet 50 can be located on the left side 24e of the compressor housing 24, and the air inlet 52 can be located on the left edge of the front surface 24a of the compressor housing 24. Alternatively, the air inlet 50 can be located on the right side 24f of the compressor housing 24, and the air inlet 52 can be located on the right edge of the front surface 24a of the compressor housing 24. The guide member 62 can also be located on the surface of the compressor housing 24 where the air inlet 50 is located. The shielding member 66 can also be located on the surface of the compressor housing 24 where the air inlet 50 is located.

[0082] If necessary, in addition to the air inlet 50 provided on other surfaces, an additional air inlet 50 may be provided on the front surface 24a or the rear surface 24b of the compressor housing 24.

[0083] In the above embodiment, the case where the exhaust port 54 is provided on the rear surface 24b of the compressor housing 24 is illustrated, but the exhaust port 54 may also be provided in other parts of the compressor housing 24.

[0084] In the above embodiments, the compressor cooling system 28 is illustrated as an example of an air-cooled heat exchanger. However, in addition to an air-cooled heat exchanger, the compressor cooling system 28 may also include a liquid-cooled (e.g., water-cooled) heat exchanger. Therefore, the compressor cooling system 28 may include a refrigerant gas cooler that 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 that cools the oil circulation line 20 through heat exchange between the oil and a cooling medium. A cooling medium inlet and a cooling medium outlet may be provided on the compressor housing 24. The cooling medium can be supplied to the compressor 12 from the outside through the cooling medium inlet, and after passing through the refrigerant gas cooler and the oil cooler, it is discharged to the outside of the compressor 12 from the cooling medium outlet. In this way, the compression heat generated in the compressor body 16 can be removed from the compressor 12 along with the cooling medium.

[0085] In the above embodiments, the use of the cryogenic refrigerator 10 as a cooling source for a measuring device is illustrated, but the cryogenic refrigerator 10 can also be used to cool various other objects. 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, for example, on a single crystal pulling device, an NMR (Nuclear Magnetic Resonance) system, an MRI (Magnetic Resonance Imaging) system, an accelerator such as a cyclotron, a nuclear fusion system, or other high magnetic field utilization equipment (not shown) as its magnetic field source to generate the high magnetic field required by the device.

[0086] According to the embodiments, the present invention has been described using specific statements. However, the embodiments are merely illustrative of one aspect of the principles and applications of the present invention. Many variations or configuration changes are permitted in the embodiments without departing from the spirit of the present invention as defined in the claims.

Claims

1. A compressor for an ultra-low temperature refrigeration machine, characterized in that, have: A compressor housing having an air inlet on a surface different from the front surface of the compressor housing, and an air intake for the air inlet at the edge of the front surface of the compressor housing; and An airflow generator, disposed within the compressor housing, is used to generate an airflow from the air inlet through the air intake port into the compressor housing.

2. The compressor for an ultra-low temperature refrigeration machine according to claim 1, characterized in that, The compressor housing has the air inlet on its bottom surface facing the compressor mounting surface, and the air intake is located between the lower edge of the compressor mounting surface and the front surface.

3. The compressor for an ultra-low temperature refrigeration machine according to claim 2, characterized in that, The compressor housing has a guide on its bottom surface that directs the airflow from the air inlet to the air intake.

4. The compressor for an ultra-low temperature refrigeration machine according to claim 3, characterized in that, The guide forms part of a direct-acting mechanism that supports the compressor for the cryogenic refrigeration machine so that it can move relative to the compressor mounting surface.

5. The compressor for an ultra-low temperature refrigeration machine according to claim 1, characterized in that, The compressor housing has an exhaust port for discharging exhaust air at a location different from the front surface and the surface different from the front surface.

6. The compressor for an ultra-low temperature refrigeration machine according to claim 5, characterized in that, The surface of the compressor housing that is different from the front surface is configured to prevent the exhaust air from flowing into the air inlet.

7. The compressor for an ultra-low temperature refrigeration machine according to claim 5, characterized in that, The compressor housing has the exhaust port on the rear surface of the compressor housing.

8. The compressor for an ultra-low temperature refrigeration machine according to claim 5, characterized in that, The compressor includes a transformer, which is located outside the compressor housing and near the exhaust port.

9. The compressor for an ultra-low temperature refrigeration machine according to claim 8, characterized in that, The transformer has an exhaust inlet for introducing the exhaust air.

10. The compressor for an ultra-low temperature refrigeration machine according to any one of claims 1 to 9, characterized in that, It also includes a compressor component, which is disposed within the compressor housing and generates vibration and / or heat during operation. The compressor housing includes a support plate that supports the compressor components and is supported on the bottom surface of the compressor housing via vibration damping seats. The vibration damping seat is positioned on the outside of the support plate when viewed from above.

11. The compressor for an ultra-low temperature refrigeration machine according to claim 10, characterized in that, The compressor housing has a fixing component installed on the outer periphery of the support plate, and the vibration damping seat is fixed to the fixing component.

12. A compressor for an ultra-low temperature refrigeration machine, characterized in that, have: Compressor housing; and The compressor component, disposed within the compressor housing, generates vibration and / or heat during operation. The compressor housing includes a support plate that supports the compressor components and is supported on the bottom surface of the compressor housing via vibration damping seats. The vibration damping seat is positioned on the outside of the support plate when viewed from above.

13. A compressor housing for an ultra-low temperature refrigeration machine, characterized in that, have: Front surface; and The surface different from the front surface has an air inlet. An air inlet for the air intake is provided at the edge of the front surface.

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