Cryogenic refrigerator compressor and cryogenic refrigerator compressor housing

Abstract

To efficiently cool the compressor for cryogenic refrigerators. [Solution] The compressor 12 for the cryogenic refrigerator 10 comprises a compressor housing 24 having an air intake port 50 on a surface different from the front surface 24a of the compressor housing 24, and an air intake port 52 for the air intake port 50 on the edge of the front surface 24a, and an airflow generator 29 disposed inside the compressor housing 24 that generates an airflow from the air intake port 52 into the compressor housing 24 through the air intake port 50. The compressor housing 24 may have an air intake port 50 on the bottom surface 24d of the compressor housing 24 facing the compressor mounting surface 26, and an air intake port 52 between the compressor mounting surface 26 and the lower edge of the front surface 24a.

Description

Technical Field

[0001] The present invention relates to a compressor for a cryogenic refrigerator and a housing for a compressor for a cryogenic refrigerator.

Background Art

[0002] A cryogenic refrigerator can be used for cryogenic cooling of measurement elements in measurement devices in various fields, such as superconducting single photon detectors, gravitational wave detectors, voltage standards, and the like. In this case, the cryogenic refrigerator has a cold head for cooling the measurement element and a compressor for supplying and discharging a refrigerant gas such as helium gas to the cold head. The heat absorbed by the cold head is dissipated from the compressor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Measurement devices as described above may include a large number of component devices such as a cryostat equipped with a cryogenic refrigerator, a power supply, a detector, a vacuum pump, and the like. If a footprint is required for each component device for installation, a considerably large corresponding installation space may be required to install an entire set of measurement devices. Also, when installing or moving the measurement device, it is necessary to perform relatively laborious work such as removing and packing electrical wiring and gas piping from each component device, unpacking each packed component device at the site, and reconnecting the devices to each other with electrical wiring and gas piping. As one solution to such problems, the inventor proposes integrating the component devices of the measurement device into a rack. By storing the component devices in the storage shelves of the rack, the footprint of the measurement device can be reduced. Also, by transporting the entire rack with the measurement device, installation and movement become easier.

[0005] However, the inventors recognized that such measuring devices may have limitations on heat dissipation from the compressor for cryogenic refrigerators. This is because, in addition to having to be miniaturized to fit in a rack, the compressor is surrounded by the walls and floor of the rack, which can hinder heat dissipation. In particular, if the compressor is air-cooled, the direction and location of intake and exhaust are restricted, which can have a significant impact on heat dissipation capacity. A decrease in the heat dissipation capacity from the compressor is undesirable because it can lead to a decrease in the performance and lifespan of the cryogenic refrigerator.

[0006] One exemplary object of a certain aspect of the present invention is to efficiently cool a compressor for a cryogenic refrigerator. [Means for solving the problem]

[0007] According to one aspect of the present invention, a compressor for a cryogenic refrigerator comprises a compressor housing having an air intake on a surface different from the front of the compressor housing and an air intake port for the air intake on the edge of the front, and an airflow generator disposed inside the compressor housing that generates an airflow from the air intake port into the compressor housing.

[0008] According to one aspect of the present invention, a compressor for a cryogenic refrigerator comprises a compressor housing and compressor components disposed within the compressor housing and generating vibration and / or heat during operation. The compressor housing supports the compressor components and includes a support plate supported on the bottom surface of the compressor housing via vibration-damping mounts. The vibration-damping mounts are located outside the support plate in a top view.

[0009] According to one aspect of the present invention, the compressor housing for a cryogenic refrigerator comprises a front surface and a surface different from the front surface having an air intake, and has an air intake port for the air intake at the edge of the front surface. [Effects of the Invention]

[0010] According to the present invention, a compressor for a cryogenic refrigerator can be cooled efficiently. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing a cryogenic refrigerator according to an embodiment. [Figure 2] This figure schematically shows the external appearance of the compressor unit of a cryogenic refrigerator according to an embodiment. [Figure 3] This figure schematically shows the external appearance of the compressor unit of a cryogenic refrigerator according to an embodiment. [Figure 4] This figure schematically shows the external appearance of the compressor unit of a cryogenic refrigerator according to an embodiment. [Figure 5] This figure schematically shows the external appearance of the compressor unit of a cryogenic refrigerator according to an embodiment. [Figure 6] This diagram schematically shows the inside of the compressor unit of a cryogenic refrigerator according to an embodiment. [Figure 7] This diagram schematically shows the inside of the compressor unit of a cryogenic refrigerator according to an embodiment. [Figure 8] This diagram schematically shows the inside of the compressor unit of a cryogenic refrigerator according to an embodiment. [Modes for carrying out the invention]

[0012] The embodiments for carrying out the present invention will be described in detail below with reference to the drawings. In the description and drawings, identical or equivalent components, members, and processes are denoted by the same reference numerals, and redundant descriptions will be omitted as appropriate. The scale and shape of the illustrated parts are set for convenience to facilitate the explanation and are not to be interpreted restrictively unless otherwise specified. The embodiments are illustrative and do not limit the scope of the present invention in any way. Not all features or combinations thereof described in the embodiments are necessarily essential to the invention.

[0013] Figure 1 is a schematic diagram showing a cryogenic refrigerator according to an embodiment. The cryogenic refrigerator 10 is used to provide cryogenic cooling to an object or medium. For example, the cryogenic refrigerator 10 may be used as a cooling source for a measuring device. The measuring device can be a measuring device in various fields, such as a superconducting single-photon detector, a gravitational wave detector, or a voltage standard.

[0014] The cryogenic refrigerator 10 comprises a compressor 12 and a cold head 14. The compressor 12 is configured to recover refrigerant gas from the cryogenic refrigerator 10 from the cold head 14, pressurize the recovered refrigerant gas, and supply the refrigerant gas back to the cold head 14. The compressor 12 is also referred to as the compressor unit. The cold head 14 is also referred to as the expander and has a room temperature section 14a and a low-temperature section 14b, also referred to as the cooling stage. The refrigerant gas is also referred to as the working gas and is usually helium gas, but other suitable gases may be used. The compressor 12 and the cold head 14 constitute the refrigeration cycle of the cryogenic refrigerator 10, thereby cooling the low-temperature section 14b to a desired cryogenic temperature. The low-temperature section 14b can cool objects to be cooled, such as measuring elements in measuring devices.

[0015] The cryogenic refrigerator 10 is, for example, a single-stage or double-stage Gifford-McMahon (GM) refrigerator, but may also be a pulse tube refrigerator, a Stirling refrigerator, or another type of cryogenic refrigerator. The cold head 14 has different configurations depending on the type of cryogenic refrigerator 10, but the compressor 12 can be configured as described below, regardless of the type of cryogenic refrigerator 10.

[0016] Generally, the pressure of the refrigerant gas supplied from the compressor 12 to the cold head 14 and the pressure of the refrigerant gas recovered from the cold head 14 to the compressor 12 are both considerably higher than atmospheric pressure and can be called the first high pressure and the second high pressure, respectively. For convenience of explanation, the first high pressure and the second high pressure are also simply called 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, or approximately 0.8 MPa.

[0017] The compressor 12 is a compressor for an oil-lubricated cryogenic refrigerator, and includes a compressor main body 16, a refrigerant gas line 18, and an oil circulation line 20. In FIG. 1, for ease of understanding, the refrigerant gas line 18 is shown by a solid line and the oil circulation line 20 is shown by a broken line. Further, the compressor 12 includes a compressor housing 24 that houses each component of the compressor 12, such as the compressor main body 16, the refrigerant gas line 18, and the oil circulation line 20.

[0018] The compressor main body 16 is configured to compress the refrigerant gas sucked from its suction port inside and discharge it from the discharge port. Oil is used in the compressor main body 16 for cooling and lubrication, and the sucked refrigerant gas is directly exposed to this oil inside the compressor main body 16. Therefore, the refrigerant gas is sent out from the discharge port in a state where a little oil is mixed in.

[0019] The compressor main body 16 may be, for example, a scroll type, a rotary type, or any other pump that boosts the refrigerant gas. The compressor main body 16 may be configured to discharge a fixed and constant refrigerant gas flow rate. Alternatively, the compressor main body 16 may be configured to make the discharged refrigerant gas flow rate variable. The compressor main body 16 may also be referred to as a compression capsule.

[0020] 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 of the refrigerant gas installed in the compressor housing 24 for sending out the refrigerant gas boosted to a high pressure by the compressor main body 16 from the compressor 12, and the suction port 31 is an inlet of the refrigerant gas installed in the compressor housing 24 for receiving the low-pressure refrigerant gas into the compressor 12. The discharge flow path �2 and the suction flow path 33 are housed in the compressor housing 24. The discharge port of the compressor main body 16 is connected to the discharge port 30 by the discharge flow path 32, and the suction port 31 is connected to the suction port of the compressor main body 16 by the suction flow path 33.

[0021] The refrigerant gas line 18 is connected to the cold head 14. The room temperature section 14a of the cold head 14 is provided with a high-pressure port 40 and a low-pressure port 41. The high-pressure port 40 is connected to the discharge port 30 by a high-pressure pipe 42, and the low-pressure port 41 is connected to the suction port 31 by a low-pressure pipe 43.

[0022] The discharge channel 32 is equipped with an oil separator 34 and an adsorber 35. The oil separator 34 is provided to separate oil that mixes with the refrigerant gas as it passes through the compressor body 16. The adsorber 35 is provided to remove residual contaminants in the refrigerant gas, such as vaporized oil, from the refrigerant gas by adsorption. The oil separator 34 and the adsorber 35 are connected in series. In the discharge channel 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.

[0023] Meanwhile, a storage tank 36 is provided in the intake passage 33. The storage tank 36 is provided as a volume for removing pulsations contained in the low-pressure refrigerant gas returning from the cold head 14 to the compressor 12.

[0024] Furthermore, the refrigerant gas line 18 is provided with a bypass valve 38 that connects the discharge passage 32 to the suction passage 33, bypassing the compressor body 16. For example, the bypass valve 38 branches off from the discharge passage 32 between the oil separator 34 and the adsorber 35 and connects to the suction passage 33 between the compressor body 16 and the storage tank 36. The bypass valve 38 is provided for refrigerant gas flow rate control and / or for equalizing the pressure between the discharge passage 32 and the suction passage 33 when the compressor 12 is stopped.

[0025] The oil circulation line 20 connects the oil outlet of the compressor body 16 to the oil inlet in order to return the oil flowing out of the compressor body 16 back to the compressor body 16. The oil circulation line 20 may be provided with an orifice to control the flow rate of oil flowing through it. The oil circulation line 20 may also be provided with a filter to remove dust contained in the oil.

[0026] Furthermore, an oil return line 21 is provided that connects 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 an orifice to control the amount of oil returned to the compressor body 16 may be provided in the middle of the oil return line 21.

[0027] The compressor 12 also 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 provided in the cryogenic refrigerator 10 and to control various devices of the cryogenic refrigerator 10 based on the sensor outputs. Multiple electrical components, including sensors, may be housed together with the control panel 39 in the compressor housing 24. Each sensor may be connected to the control panel 39 by a communication cable. Electrical components controlled based on sensor outputs may include, for example, a compressor motor 17 that drives the compressor body 16, a bypass valve 38, and a cold head motor that drives the cold head 14.

[0028] The compressor 12 may be equipped with various sensors, such as pressure sensors and temperature sensors, to monitor its state. For example, a first pressure sensor 37a may be positioned in the discharge passage 32 to measure the pressure of the refrigerant gas flowing through the discharge passage 32. The first pressure sensor 37a is configured to output a first measured pressure signal PH, representing the measured pressure, to the control panel 39. A second pressure sensor 37b may be positioned in the suction passage 33 to measure the pressure of the refrigerant gas flowing through the suction passage 33. The second pressure sensor 37b is configured to output a second measured pressure signal PL, representing the measured pressure, to the control panel 39. Temperature sensors may include a refrigerant gas temperature sensor provided in the refrigerant gas line 18, an oil temperature sensor provided in the oil circulation line 20, and a cooling temperature sensor provided in the low-temperature section 14b of the cold head 14. The temperature sensors are configured to output a signal representing the measured temperature to the control panel 39.

[0029] Figures 2 to 4 are schematic diagrams illustrating the external appearance of the compressor unit of a cryogenic refrigerator according to an embodiment. Figure 2 schematically shows the lower front of the compressor 12. Figure 3 schematically shows the bottom of the compressor 12. Figure 4 schematically shows a perspective view of the compressor 12 seen from below.

[0030] As shown in Figures 2 to 4, the compressor housing 24 has a rectangular parallelepiped shape with six faces, comprising a front face 24a, a rear face 24b, a top face 24c, a bottom face 24d, a left side face 24e, and a right side face 24f. The rear face 24b faces away from the front face 24a. Between the front face 24a and the rear face 24b, the top face 24c is positioned above, the bottom face 24d is positioned below, and the left side face 24e and the right side face 24f are positioned to the left and right, respectively, when viewed from the front face 24a. These faces of the compressor housing 24 may be thin, plate-like panel members formed of metal such as stainless steel or other appropriate material.

[0031] The bottom surface 24d of the compressor housing 24 faces the compressor mounting surface 26. When the cryogenic refrigerator 10 is housed in a rack, the compressor mounting surface 26 may be a shelf surface of the rack. The rack may be a rack conforming to standard specifications, such as a 19-inch rack. The objects to be cooled by the cryogenic refrigerator 10, such as measuring devices, may be housed in the rack together with the cryogenic refrigerator 10.

[0032] When the compressor 12 is housed in a rack, the top surface 24c, bottom surface 24d, left side surface 24e, and right side surface 24f of the compressor housing 24 are covered by the rack's shelves and walls. On the other hand, the front surface 24a and rear surface 24b of the compressor housing 24 are not covered by the rack's shelves and walls, making them easily accessible. Therefore, various user interfaces may be provided on the front surface 24a and rear surface 24b of the compressor housing 24.

[0033] For example, the front surface 24a of the compressor housing 24 may be provided with a display panel that displays information about the cryogenic refrigerator 10, such as the operating time of the cryogenic refrigerator 10, a pressure gauge that shows 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 line 18, and a main switch for the cryogenic refrigerator 10.

[0034] The rear surface 24b of the compressor housing 24 may provide piping and power connections. For example, the rear surface 24b of the compressor housing 24 may be provided with a discharge port 30 and an intake port 31 of the refrigerant gas line 18. The rear surface 24b of the compressor housing 24 may also be provided with an input power connector, a cold head connector, and a communication cable connector. The input power connector is connected to an external power source such as commercial power, thereby powering the cryogenic refrigerator 10. The cold head connector is connected to electrical wiring for power supply to the cold head 14 and for control of the cold head 14. The communication cable connector is connected to an external device by a communication cable, thereby enabling communication between the compressor 12 and the external device.

[0035] The compressor 12 further comprises 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 heat exchange between the airflow generated in the compressor housing 24 by the airflow generator 29 and the compressor components such as the refrigerant gas line 18 and the oil circulation line 20. The airflow generator 29 may be a cooling fan that forcibly cools the refrigerant gas line 18 and the oil circulation line 20 with airflow.

[0036] The airflow generator 29 may be configured to draw in air from outside the compressor housing 24 and blow it onto the refrigerant gas line 18 and the oil circulation line 20 to cool them. Alternatively, the airflow generator 29 may be configured to cool the refrigerant gas line 18 and the oil circulation line 20 by drawing air around them out of the compressor housing 24. 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 airflow generator 29 may be configured to cool the refrigerant gas line 18 between the compressor body 16 and the oil separator 34 in the discharge passage 32.

[0037] As shown in Figures 1 to 4, in this embodiment, the compressor housing 24 has an air intake port 50, an air intake port 52 for the air intake port 50, and an exhaust port 54. The airflow generator 29 generates an airflow into the compressor housing 24 from the air intake port 52 through the air intake port 50. In Figures 1 and 4, for ease of understanding, the airflow flowing into the compressor housing 24 from the air intake port 52 through the air intake port 50 is schematically shown by arrow 56. The airflow generator 29 also discharges the airflow that has flowed into the compressor housing 24 from the air intake port 50 as exhaust air from the exhaust port 54 to the outside of the compressor housing 24. In Figures 1 and 4, for ease of understanding, the exhaust air is schematically shown by arrow 58.

[0038] The air intake 50 is located on a surface different from the front surface 24a of the compressor housing 24, in this example, on the bottom surface 24d of the compressor housing 24. The air intake 50 may be at least one opening that penetrates the compressor housing 24, for example, a plurality of slits or holes. The air intake 50 may be located in a portion of a particular surface of the compressor housing 24 (in this example, the bottom surface 24d), for example, in a portion of this surface adjacent to the air intake 52 (in this example, in a portion of the bottom surface 24d adjacent to the front surface 24a). Alternatively, the air intake 50 may be located across the entire particular surface of the compressor housing 24. To form the air intake 50, at least a portion of a particular surface of the compressor housing 24 (in this example, the bottom surface 24d) may be made of a perforated plate, such as perforated metal or wire mesh.

[0039] The air intake 52 is located at the edge of the front surface 24a of the compressor housing 24, specifically at the lower edge of the front surface 24a in this example. More specifically, the gap formed between the compressor mounting surface 26 and the lower edge of the front surface 24a acts as the air intake 52.

[0040] From the viewpoint of reducing wind noise, as described later, the total area of ​​the air intake 52 (i.e., the sum of the areas of the air intake 52 in the plane along the front surface 24a of the compressor housing 24) may be smaller than the total area of ​​the air intake 50 (i.e., the sum of the areas of the air intake 50 in the plane along the bottom surface 24d of the compressor housing 24). For example, the total area of ​​the air intake 52 may be 20% to 50% of the total area of ​​the air intake 50, taking into consideration the balance between wind noise and airflow rate.

[0041] To form an air intake 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 supports the compressor 12 somewhat above the compressor mounting surface 26. The support 60 may be provided on the bottom surface 24d of the compressor housing 24 and support the compressor 12 on the compressor mounting surface 26.

[0042] The compressor housing 24 includes at least one guide 62 that guides the airflow from the air intake 52 to the air intake port 50. The guide 62 is provided on the bottom surface 24d of the compressor housing 24. The guide 62 may constitute part of the support 60.

[0043] In this example, three guides 62 extend linearly from the lower edge of the front surface 24a to 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 intake passage from the air intake 52 to the air intake port 50 is formed between two adjacent guides 62.

[0044] As illustrated in Figure 1, a filter 68 may be installed at any position in the intake passage to separate dust from the airflow and prevent dust from entering the compressor 12.

[0045] As shown in Figure 2, the guide 62 may constitute part of a linear motion mechanism 64 that supports the compressor 12 so as to be movable relative to the compressor mounting surface 26. In the illustrated example, two guides 62 positioned on both sides of the bottom surface 24d constitute part of the linear motion mechanism 64. The linear motion mechanism 64 may be configured to move the compressor 12 linearly in the front-rear direction relative to the compressor mounting surface 26. The linear motion mechanism 64 may be, for example, a slide rail having a fixed side rail fixed to the compressor mounting surface 26, and the guide 62 may be a movable side rail fixed to the bottom surface 24d of the compressor housing 24 and movably supported by the fixed side rail. This configuration is advantageous because, when the compressor 12 is housed in a rack, the compressor 12 can be easily moved in and out of the rack using the linear motion mechanism 64.

[0046] The exhaust port 54 is located in a different place from the front 24a and bottom 24d of the compressor housing 24; in this example, it is located on the rear 24b of the compressor housing 24. The exhaust port 54 may be at least one opening that penetrates the compressor housing 24, for example, a plurality of slits or holes. The exhaust port 54 may be located in at least a portion of a particular surface of the compressor housing 24 (in this example, the rear 24b). To form the exhaust port 54, at least a portion of a particular surface of the compressor housing 24 may be formed of a perforated plate, such as perforated metal or wire mesh.

[0047] During 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 fluctuations of the refrigerant gas expansion space within the cold head 14 and the synchronized pressure fluctuations of the refrigerant gas in the expansion space, thereby cooling the low-temperature section 14b of the cold head 14 to a desired cryogenic temperature. If the cold head 14 is, for example, two-stage, the first cooling stage is cooled to a first cooling temperature, for example, in the range of about 30K to about 80K, and the second cooling stage is cooled to a second cooling temperature lower than the first cooling temperature, for example, 1K to 20K. The second cooling temperature may be about 4.2K (liquid helium temperature) or lower.

[0048] The 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 to the suction port 31 of the compressor 12. The refrigerant gas is recovered through the storage tank 36 on the suction passage 33 to the suction port of the compressor body 16. The refrigerant gas is compressed and pressurized by the compressor body 16. The refrigerant gas discharged from the discharge port of the compressor body 16 passes through the oil separator 34 and the adjuster 35, and exits the compressor 12 through the discharge port 30. The refrigerant gas is supplied to the inside of the cold head 14 through the high-pressure piping 42 and the high-pressure port 40.

[0049] During operation of the cryogenic refrigerator 10, the airflow generator 29 operates, causing an airflow (arrow 56) to flow from the air intake 52 through the air intake port 50 into the compressor housing 24. The refrigerant gas and oil, heated by the compression heat in the compressor body 16, are cooled by heat exchange with the airflow. The refrigerant gas is cooled by the compressor cooling system 28 and supplied from the compressor 12 to the cold head 14. The oil is cooled by the compressor cooling system 28 and returned to the compressor body 16. The airflow, heated by heat exchange, is discharged as exhaust air (arrow 58) from the compressor housing 24 through the exhaust port 54. In this way, the compression heat generated in the compressor body 16 is discharged outside the compressor 12 along with the airflow.

[0050] According to this embodiment, relatively cool and fresh air can be drawn into the compressor housing 24 from the space in front of the compressor 12 through the air intake 52 and the air intake port 50. This airflow can be used to promote heat dissipation from the compressor 12, allowing the compressor 12 to be cooled efficiently. This suppresses excessive temperature rise of the compressor 12 due to insufficient heat dissipation, and the resulting decrease in the performance and lifespan of the cryogenic refrigerator.

[0051] Such a cooling configuration is particularly advantageous when the compressor 12 is housed in a rack. Even if the compressor 12 is enclosed by the shelves or walls of the rack, the front 24a of the compressor 12 is typically open to the space in front of it. Cold, fresh air can be drawn into the compressor 12 from the space in front through the air intake 52 on the front 24a, allowing the compressor 12 to be cooled efficiently.

[0052] In addition, the arrangement of the air intake port 50 and the air intake port 52 according to this embodiment is also effective in reducing noise associated with airflow. In typical existing compressors, air intake ports (multiple slits, openings, etc.) may be formed on the front of the housing to take in a large amount of air. In this case, the air intake ports can become sound sources that emit wind noise due to the air passing through them. The emitted wind noise can easily propagate from the front of the housing into the surrounding space and be perceived as noise. However, in this embodiment, the air intake port 50 is not provided on the front 24a of the compressor housing 24. The air intake port 50 faces the compressor mounting surface 26. The compressor mounting surface 26 acts as a barrier, so even if wind noise is emitted from the air intake port 50, it is less likely to be transmitted to the surroundings. Therefore, noise is reduced and the quietness of the compressor 12 can be improved.

[0053] Furthermore, as shown in Figures 3 and 4, the surface of the compressor housing 24 on which the air intake port 50 is provided, in this example, the bottom surface 24d of the compressor housing 24, is configured to prevent exhaust air from flowing into the air intake port 50. Therefore, a shielding member 66 is provided. The shielding member 66 is positioned to close the gap between the surface of the compressor housing 24 on which the air intake port 50 is provided and the surface opposite it, in this example, the gap between the bottom surface 24d and the compressor mounting surface 26.

[0054] The shielding member 66 is positioned on the bottom surface 24d on the side opposite to the air intake port 52 relative to the air intake port 50. The shielding member 66 is provided 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 also be a shielding plate positioned at the rear end of the guides 62 so as to connect the guides 62 to each other.

[0055] The exhaust air coming out of the exhaust port 54 absorbs the heat from the compressor 12, so its temperature is higher than the airflow drawn in from the intake port 50. By using the shielding member 66 to prevent the exhaust air from flowing into the intake port 50, the temperature rise caused by the mixing of exhaust air into the intake airflow can be suppressed. This also contributes to the efficient cooling of the compressor 12.

[0056] Figure 5 is a schematic diagram showing the external appearance of the compressor unit of a cryogenic refrigerator according to an embodiment. Figure 5 schematically shows a perspective view of the compressor 12 as seen from the rear. As shown in the figure, 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 detachable from the compressor housing 24.

[0057] The transformer 70 is positioned on the outside of the compressor housing 24, close to the exhaust port 54. The transformer 70 may also be mounted on the compressor housing 24, for example, on the rear surface 24b of the compressor housing 24, so as to be adjacent to the exhaust port 54. In the illustrated example, the transformer 70 is positioned on one side (left side in the figure) of the rear surface 24b of the compressor housing 24, and the exhaust port 54 is provided on the other side (left side in the figure) of the rear surface 24b. In this way, the transformer 70 is positioned offset from the exhaust port 54 so as not to obstruct the flow of exhaust air coming out of the exhaust port 54.

[0058] During the operation of the cryogenic refrigerator 10, the transformer 70 generates a lot of heat and can become relatively hot. The inventors realized that the temperature of the transformer 70 can be higher than the temperature of the exhaust air, and therefore the exhaust air can be used to cool the transformer 70. By actively cooling the transformer 70 with the exhaust air, the temperature rise of the transformer 70 can be suppressed. This suppresses the deterioration of the insulation inside the transformer 70 and extends the lifespan of the transformer 70.

[0059] To facilitate the cooling of the transformer 70, the transformer 70 may have an exhaust inlet 70a for taking in exhaust air. To facilitate the intake of exhaust air, the exhaust inlet 70a may be located on the side of the transformer 70 adjacent to the exhaust port 54, as shown in the figure. The transformer 70 may also have an exhaust outlet 70b. The exhaust outlet 70b may be located on a different side of the transformer 70 from the side of the transformer 70 on which the exhaust inlet 70a is located, in the illustrated example, on the rear side of the transformer 70. The exhaust inlet 70a and the exhaust outlet 70b may each be at least one opening that penetrates the housing of the transformer 70, for example, a plurality of slits or holes.

[0060] The exhaust inlet 70a of the transformer 70 may be connected to the exhaust port 54 of the compressor 12. For example, the exhaust inlet 70a may be connected to the exhaust port 54 by a duct. In this case, the transformer 70 may be positioned facing the exhaust port 54.

[0061] Figures 6 to 8 are schematic diagrams illustrating the interior of the compressor unit of a cryogenic refrigerator according to an embodiment. Figure 6 schematically shows a portion of the cross-section shown by line AA in Figure 3. Figure 7 schematically shows a portion of the cross-section shown by line BB in Figure 6. Figure 8 schematically shows a portion of the cross-section shown by line CC in Figure 7.

[0062] As shown in Figure 6, compressor components located within the compressor housing 24 and that generate vibration and / or heat during operation may be supported by support plates 72. Such compressor components may include, for example, the compressor body 16, the airflow generator 29, the control panel 39, and various other components as described above. Note that in Figures 7 and 8, the illustration of compressor components has been omitted for the sake of clarity.

[0063] The support plate 72 is positioned inside the compressor housing 24, facing the bottom surface 24d of the compressor housing 24. The compressor housing 24 may have a double structure consisting of an outer housing and an inner housing, and the support plate 72 may form the bottom surface of the inner housing. Compressor components may be arranged inside the inner housing, and the inner housing may be arranged inside the outer housing. The outer housing may have the front surface 24a, rear surface 24b, top surface 24c, bottom surface 24d, left side surface 24e, and right side surface 24f described above.

[0064] The support plate 72 is supported on the bottom surface 24d of the compressor housing 24 via vibration-damping mounts 74. As shown in Figure 7, the vibration-damping mounts 74 are positioned outside the support plate 72 in a top view. In this example, four vibration-damping mounts 74 are provided and positioned at the four corners of the bottom surface 24d. The vibration-damping mounts 74 provide vibration-damping support to the bottom surface 24d, thereby suppressing the transmission of vibrations generated by the compressor components to the outside.

[0065] The compressor housing 24 is equipped with a fixing member 76 attached to the outer circumference of the support plate 72, and the vibration-damping mount 74 is fixed to the fixing member 76. In the illustrated example, a pair of elongated fixing pieces are used as the fixing member 76. These fixing pieces are fixed to two opposing sides of the support plate 72. As shown in Figure 8, two sides of the support plate 72 may be folded back, and the fixing pieces may be fixed to this folded portion. The cross-section of the support plate 72 has a U-shape. The folded portion also helps to increase the rigidity of the support plate 72.

[0066] As shown in Figure 7, the length of the fixing piece is longer than the length of the side of the fixed support plate 72, so that both ends of the fixing piece extend to both sides of the support plate 72. Two vibration-damping mounts 74 are fixed to each fixing piece at both ends. Each vibration-damping mount 74 is fixed to the fixing piece by an appropriate method, such as bolting, such as by sandwiching a vibration-damping material such as vibration-damping rubber between the bottom surface 24d and the fixing piece.

[0067] Since the support plate 72 is equipped with compressor components, its temperature tends to rise due to the heat generated by the compressor components. By interposing the fixing member 76 between the support plate 72 and the vibration-damping mount 74, the fixing member 76 functions as a thermal resistance. This reduces heat conduction from the support plate 72 to the vibration-damping mount 74 compared to when the vibration-damping mount 74 is directly fixed to the support plate 72. This suppresses the temperature rise of the vibration-damping mount 74, thereby reducing its deterioration and extending its lifespan.

[0068] Furthermore, since the vibration-damping mount 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 when the vibration-damping mount 74 is positioned directly below the support plate 72. In addition, the outside of the support plate 72 is located in the gap between the outer housing and the inner housing, and thus serves as a passage for the airflow drawn into the compressor housing 24 from the air intake port 50. These factors also help to suppress the temperature rise of the vibration-damping mount 74.

[0069] The present invention has been described above based on examples. Those skilled in the art will understand that the present invention is not limited to the above embodiments, that various design changes are possible, and that various modifications are possible, and that such modifications also fall within the scope of the present invention. Various features described in relation to one embodiment are applicable to other embodiments. New embodiments resulting from combinations will possess the combined effects of each of the embodiments combined.

[0070] In the above-described embodiment, the case in which the air intake port 50 is provided on the bottom surface 24d of the compressor housing 24 and the air intake port 52 is provided on the lower edge of the front surface 24a of the compressor housing 24 is described as an example, but the air intake port 50 and the air intake port 52 may be provided in other locations on the compressor housing 24.

[0071] For example, the air intake port 50 may be provided on the upper surface 24c of the compressor housing 24, and the air intake port 52 may be provided on the upper edge of the front surface 24a of the compressor housing 24. Alternatively, the air intake port 50 may be provided on the left side surface 24e of the compressor housing 24, and the air intake port 52 may be provided on the left edge of the front surface 24a of the compressor housing 24. Alternatively, the air intake port 50 may be provided on the right side surface 24f of the compressor housing 24, and the air intake port 52 may be provided on the right edge of the front surface 24a of the compressor housing 24. Similarly, the guide 62 may be provided on the surface of the compressor housing 24 on which the air intake port 50 is provided. Similarly, the shielding member 66 may be provided on the surface of the compressor housing 24 on which the air intake port 50 is provided.

[0072] If necessary, additional air intakes 50 may be provided on the front 24a or rear 24b of the compressor housing 24, in addition to the air intakes 50 provided on other sides.

[0073] In the above-described embodiment, the case in which the exhaust port 54 is provided on the rear surface 24b of the compressor housing 24 is explained as an example, but the exhaust port 54 may be provided in other locations on the compressor housing 24.

[0074] In the above-described embodiment, the case in which the compressor cooling system 28 is configured as an air-cooled heat exchanger is explained as an example. However, the compressor cooling system 28 may also include a liquid-cooled (e.g., water-cooled) heat exchanger in addition to the air-cooled heat exchanger. Therefore, the compressor cooling system 28 may include a refrigerant gas cooler that cools the refrigerant gas line 18 by 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 by heat exchange between the oil and a cooling medium. The compressor housing 24 may be provided with a cooling medium inlet and a cooling medium outlet. The cooling medium may be supplied to the compressor 12 from the outside through the cooling medium inlet, and discharged to the outside of the compressor 12 through the cooling medium outlet after passing through the refrigerant gas cooler and the oil cooler. In this way, the compression heat generated in the compressor body 16 may be removed to the outside of the compressor 12 together with the cooling medium.

[0075] In the above-described embodiment, the case in which the cryogenic refrigerator 10 is used as a cooling source for a measuring device is explained as an example, but the cryogenic refrigerator 10 may be used to cool various other objects. For example, the cryogenic refrigerator 10 may be used as a cooling source for a superconducting magnet device. A superconducting magnet device can be mounted on a high-magnetic-field device as a magnetic field source for, for example, 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 high-magnetic-field devices (not shown), and can generate the high magnetic field required for that device.

[0076] Although the present invention has been described using specific terms based on the embodiments, the embodiments only illustrate one aspect of the principle and application of the present invention, and many modifications and changes in arrangement are permitted in the embodiments, as long as they do not depart from the spirit of the present invention as defined in the claims. [Explanation of symbols]

[0077] 10 Cryogenic refrigerator, 12 Compressor, 24 Compressor housing, 24a Front, 24b Rear, 24c Top, 24d Bottom, 26 Compressor mounting surface, 29 Airflow generator, 50 Intake port, 52 Air intake port, 54 Exhaust port, 62 Guide, 64 Linear motion mechanism, 70 Transformer, 70a Exhaust intake port, 72 Support plate, 74 Vibration damping mount, 76 Fixing member.

Claims

1. A compressor housing having an air intake on a side different from the front of the compressor housing, and having an air intake port for the air intake on the edge of the front, A compressor for a cryogenic refrigerator, characterized by comprising an airflow generator disposed within the compressor housing and generating an airflow from the air intake through the air intake port into the compressor housing.

2. The compressor for cryogenic refrigerator according to claim 1, characterized in that the compressor housing has the air intake port on the bottom surface of the compressor housing facing the compressor mounting surface, and has the air intake port between the compressor mounting surface and the lower edge of the front surface.

3. The compressor for cryogenic refrigerator according to claim 2, characterized in that the compressor housing is provided with a guide on its bottom surface for guiding the airflow from the air intake to the air intake port.

4. The cryogenic refrigerator compressor according to claim 3, characterized in that the guide constitutes part of a linear motion mechanism that movably supports the cryogenic refrigerator compressor with respect to the compressor mounting surface.

5. The compressor for cryogenic refrigerator according to claim 1, characterized in that the compressor housing has an exhaust port for releasing exhaust air in a location different from the front and the other surfaces.

6. The compressor for cryogenic refrigerator according to claim 5, characterized in that the different surfaces of the compressor housing are configured to obstruct the inflow of exhaust air into the intake port.

7. The compressor for cryogenic refrigerator according to claim 5, characterized in that the compressor housing has the exhaust port on the rear surface of the compressor housing.

8. The cryogenic refrigerator compressor according to claim 5, further comprising a transformer located on the outside of the compressor housing in close proximity to the exhaust port.

9. The compressor for a cryogenic refrigerator according to claim 8, characterized in that the transformer has an exhaust inlet for taking in the exhaust air.

10. The compressor further comprises compressor components disposed within the compressor housing that generate vibration and / or heat during operation, The compressor housing supports the compressor components and is provided with a support plate supported on the bottom surface of the compressor housing via an anti-vibration mount. The compressor for a cryogenic refrigerator according to any one of claims 1 to 9, characterized in that the vibration-damping mount is positioned on the outside of the support plate when viewed from above.

11. The compressor for cryogenic refrigerator according to claim 10, characterized in that the compressor housing includes a fixing member attached to the outer circumference of the support plate, and the vibration-damping mount is fixed to the fixing member.

12. Compressor housing and The compressor housing includes a compressor component that is arranged inside the compressor housing and generates vibration and / or heat during operation, The compressor housing supports the compressor components and is provided with a support plate supported on the bottom surface of the compressor housing via an anti-vibration mount. The compressor for a cryogenic refrigerator is characterized in that the vibration-damping mount is positioned on the outside of the support plate when viewed from above.

13. Front and It has an air intake and a surface different from the front surface, A compressor housing for a cryogenic refrigerator, characterized in that it has an air intake port for the aforementioned air intake port on the edge of the front surface.

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