Compressor for cryogenic refrigerating machine

Abstract

To easily perform a control panel detaching work in a compressor for a cryogenic refrigerating machine.SOLUTION: A compressor 12 for a cryogenic refrigerating machine 10 includes a control panel 50, and a compressor housing 24 including a front panel 24a and housing the control panel 50. The front panel 24a includes: a first panel part 28 providing pipe connection; and a second panel part 29 detachably connected to the first panel part 28 and loading the control panel 50. The control panel 50 may be drawn out forward from the compressor housing 24 with the second panel part 29.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a compressor for a cryogenic refrigerator. [Background technology]

[0002] Generally, a cryogenic refrigerator such as a Gifford-McMahon (GM) refrigerator has a refrigerant gas compressor to supply high-pressure refrigerant gas to the cold head. The compressor has components such as a compressor body, an oil separator, an adsorber, a storage tank, and a control device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2001-74326 A Summary of the Invention [Problem to be solved by the invention]

[0004] In existing cryogenic refrigerator compressors, the front panel of the compressor housing may be connected to the cold head supply and return piping for refrigerant gas. Additionally, the front panel may also be connected to the supply and return piping for coolant liquid to a heat exchanger located within the compressor housing to cool the compressor. The compressor control panel may be located within the compressor housing behind the front panel.

[0005] In a compressor with such a housing design, when removing the control panel, the worker must first remove the front panel from the compressor housing. However, before removing the front panel, it is necessary to drain the refrigerant gas from the refrigerant gas pipes and the coolant from the coolant liquid pipes, and then remove these pipes from the front panel. In addition, other compressor components such as an adsorber may be fastened to the front panel, and in that case, they must be removed from the front panel in advance. Therefore, in the existing design, the removal of the control panel from the compressor requires a preliminary process, as if the compressor was disassembled into individual parts, which is quite time-consuming.

[0006] An exemplary object of an embodiment of the present invention is to facilitate removal of a control panel in 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 includes a control panel and a compressor housing including a front panel and housing the control panel. The front panel includes a first panel portion providing piping connections and a second panel portion removably coupled to the first panel portion and mounting the control panel. Effect of the Invention

[0008] According to the present invention, the removal operation of a control panel in a compressor for a cryogenic refrigerator can be facilitated. [Brief description of the drawings]

[0009] [Figure 1] 1 is a diagram illustrating a schematic diagram of a cryogenic refrigerator according to an embodiment; [Diagram 2] 1 is a schematic perspective view showing an appearance of a compressor according to an embodiment; [Diagram 3] FIG. 2 is a schematic perspective view showing an arrangement of equipment inside a compressor according to an embodiment. [Figure 4] FIG. 2 is a schematic perspective view showing an arrangement of equipment inside a compressor according to an embodiment. [Diagram 5] FIG. 2 is a plan view illustrating a schematic view of a portion of a front panel of a compressor housing in the embodiment. [Figure 6] FIG. 2 is a side view illustrating a schematic view of a portion of a front panel of a compressor housing in the embodiment. [Figure 7] FIG. 2 is a schematic plan view showing the rear surface of the control panel in the embodiment. [Figure 8] FIG. 2 is a schematic top view showing a passband of a control panel according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, the embodiments for carrying out the present invention will be described in detail with reference to the drawings. In the description and drawings, the same or equivalent components, members, and processes are given the same reference numerals, and duplicated descriptions are omitted as appropriate. The scale and shape of each part shown in the drawings are set for convenience in order to facilitate the description, and are not to be interpreted as being limiting unless otherwise specified. The embodiments are merely examples, and do not limit the scope of the present invention in any way. All features and combinations thereof described in the embodiments are not necessarily essential to the invention.

[0011] FIG. 1 is a schematic diagram of a cryogenic refrigerator 10 according to an embodiment. The cryogenic refrigerator 10 is utilized to provide cryogenic cooling to an object or medium. For example, the cryogenic refrigerator 10 may be used as a cooling source for a superconducting magnet device. The superconducting magnet device is mounted in a high magnetic field device as a magnetic field source for, for example, a single crystal pulling device, a nuclear magnetic resonance (NMR) system, a magnetic resonance imaging (MRI) system, an accelerator such as a cyclotron, a high energy physics system such as a nuclear fusion system, or other high magnetic field device (not shown), and can generate a high magnetic field required for the device.

[0012] The cryogenic refrigerator 10 includes a compressor 12 and a cold head 14. The compressor 12 is configured to recover the refrigerant gas of the cryogenic refrigerator 10 from the cold head 14, pressurize the recovered refrigerant gas, and supply the refrigerant gas to the cold head 14 again. The compressor 12 is also called a compressor unit. The cold head 14 is also called an expander and has a room temperature section 14a and a low temperature section 14b, also called a cooling stage. The refrigerant gas is also called a working gas, and is typically helium gas, but other suitable gases may be used. The compressor 12 and the cold head 14 form a refrigeration cycle of the cryogenic refrigerator 10, thereby cooling the low temperature section 14b to a desired cryogenic temperature. The low temperature section 14b can cool an object to be cooled, such as a superconducting magnet.

[0013] Cryogenic refrigerator 10 is, by way of example, a single-stage or two-stage Gifford-McMahon (GM) refrigerator, but may also be a pulse tube refrigerator, a Stirling refrigerator, or other type of cryogenic refrigerator. Cold head 14 has a different configuration depending on the type of cryogenic refrigerator 10, but compressor 12 may have the configuration described below regardless of the type of cryogenic refrigerator 10.

[0014] Generally, the pressure of the refrigerant gas supplied from the compressor 12 to the cold head 14 and the pressure of the refrigerant gas recovered from the cold head 14 to the compressor 12 are both significantly higher than atmospheric pressure and can be 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 the high pressure and the low pressure, respectively. Typically, the high pressure is, for example, 2 to 3 MPa. The low pressure is, for example, 0.5 to 1.5 MPa, e.g., about 0.8 MPa.

[0015] The compressor 12 is an oil-lubricated compressor for a cryogenic refrigerator, and includes a compressor body 16, a refrigerant gas line 18, and an oil circulation line 20. In order to facilitate understanding, the refrigerant gas line 18 is indicated by a solid line, and the oil circulation line 20 is indicated by a dashed line in Fig. 1. The compressor 12 also includes a compressor housing 24 that houses each of the components of the compressor 12, such as the compressor body 16, the refrigerant gas line 18, and the oil circulation line 20.

[0016] The compressor body 16 is configured to compress the refrigerant gas drawn in from its suction port and discharge it from its discharge port. The compressor body 16 uses oil for cooling and lubrication, and the drawn refrigerant gas is directly exposed to this oil inside the compressor body 16. Therefore, the refrigerant gas is discharged from the discharge port with a small amount of oil mixed in.

[0017] The compressor body 16 may be, for example, a scroll, rotary, or other pump that pressurizes the refrigerant gas. The compressor body 16 may be configured to deliver a fixed, constant flow rate of refrigerant gas. Alternatively, the compressor body 16 may be configured to deliver a variable flow rate of refrigerant gas. The compressor body 16 may also be referred to as a compression capsule.

[0018] The refrigerant gas line 18 includes a discharge port 30, a suction port 31, a discharge passage 32, and a suction passage 33. The discharge port 30 is an outlet port of the refrigerant gas provided in the compressor housing 24 for sending out the refrigerant gas pressurized to a high pressure by the compressor body 16 from the compressor 12, and the suction port 31 is an inlet port of the refrigerant gas provided in the compressor housing 24 for receiving the low-pressure refrigerant gas into the compressor 12. The discharge passage 32 and the suction passage 33 are housed in the compressor housing 24. The discharge port of the compressor body 16 is connected to the discharge port 30 by the discharge passage 32, and the suction port 31 is connected to the suction port of the compressor body 16 by the suction passage 33.

[0019] The refrigerant gas line 18 is connected to the cold head 14. A high-pressure port 40 and a low-pressure port 41 are provided in the room-temperature section 14a of the cold head 14. The high-pressure port 40 is connected to the discharge port 30 by a high-pressure pipe 42, and the low-pressure port 41 is connected to the suction port 31 by a low-pressure pipe 43.

[0020] An oil separator 34 and an advertiser 35 are provided in the discharge flow path 32. The oil separator 34 is provided to separate oil that is mixed into the refrigerant gas as it passes through the compressor body 16 from the refrigerant gas. The advertiser 35 is provided to remove contaminants remaining in the refrigerant gas, such as vaporized oil, from the refrigerant gas by adsorption. The oil separator 34 and the advertiser 35 are connected in series. In the discharge flow path 32, the oil separator 34 is disposed on the compressor body 16 side, and the advertiser 35 is disposed on the discharge port 30 side.

[0021] An oil return line 21 is provided to connect the oil separator 34 to the compressor body 16. The oil recovered in the oil separator 34 can be returned to the compressor body 16 through the oil return line 21. A filter for removing dust contained in the oil separated in the oil separator 34 and an orifice for controlling the amount of oil returned to the compressor body 16 may be provided midway in the oil return line 21.

[0022] On the other hand, a storage tank 36 is provided in the suction passage 33. The storage tank 36 is provided as a volume for removing pulsation contained in the low-pressure refrigerant gas returning from the cold head 14 to the compressor 12.

[0023] In addition, the refrigerant gas line 18 is provided with a bypass valve 38 that connects the discharge passage 32 to the suction passage 33 so as to bypass the compressor body 16. As an example, the bypass valve 38 branches off from the discharge passage 32 between the oil separator 34 and the adsorber 35, and is connected to the suction passage 33 between the compressor body 16 and the storage tank 36. The bypass valve 38 is provided for controlling the flow rate of the refrigerant gas and / or for equalizing the pressure in the discharge passage 32 and the suction passage 33 when the compressor 12 is stopped.

[0024] The oil circulation line 20 connects an oil outlet of the compressor body 16 to an oil inlet so as to return the oil flowing out from the compressor body 16 to the compressor body 16. The oil circulation line 20 may be provided with an orifice that controls the flow rate of oil flowing therethrough. The oil circulation line 20 may also be provided with a filter that removes dust contained in the oil.

[0025] The compressor 12 further includes a heat exchanger 22 that is housed in a compressor housing 24 and cools the compressor 12. The heat exchanger 22 includes a refrigerant gas cooler 22a that cools the refrigerant gas line 18 by heat exchange between the refrigerant gas and a cooling medium, and an oil cooler 22b that cools the oil circulation line 20 by heat exchange between the oil and the cooling medium.

[0026] The refrigerant gas cooler 22a is disposed between the compressor body 16 and the oil separator 34 in the discharge passage 32, and cools the high-pressure refrigerant gas heated by the heat of compression generated by the compression of the refrigerant gas in the compressor body 16. The refrigerant gas cooler 22a cools the refrigerant gas by heat exchange between the refrigerant gas and a cooling medium. The cooled refrigerant gas is purified by the oil separator 34 and the absorber 35. The oil cooler 22b cools the oil by heat exchange between the oil flowing out from the oil outlet of the compressor body 16 to the oil circulation line 20 and the cooling medium. The cooled oil is returned to the compressor body 16 from the oil inlet of the compressor body 16. The cooling medium is supplied to the compressor 12 from the outside through the cooling medium intake port 44, passes through the refrigerant gas cooler 22a and the oil cooler 22b, and is discharged to the outside of the compressor 12 from the cooling medium discharge port 45. The cooling medium may be a cooling liquid, for example, water. In this manner, the heat of compression generated in the compressor body 16 is removed together with the cooling medium to the outside of the compressor 12. Note that the cooling medium may be cooled, for example, by a chiller (not shown) and supplied again.

[0027] In this embodiment, the heat exchanger 22 is a double-tube type heat exchanger. Thus, the heat exchanger 22 has an outer tube and an inner tube inserted therein. A cooling medium is supplied to one of the outer tube and the inner tube, and a fluid to be cooled is supplied to the other, whereby heat exchange between the cooling medium and the target fluid is performed, and the fluid can be cooled. For example, in the refrigerant gas cooler 22a, cooling water may be supplied to the outer tube, and refrigerant gas may be supplied to the inner tube. In the oil cooler 22b, cooling water may be supplied to the outer tube, and oil may be supplied to the inner tube.

[0028] During operation of the cryogenic refrigerator 10, refrigerant gas is supplied from the compressor 12 to the cold head 14, and a refrigeration cycle (e.g., a GM cycle) is formed by periodic volume fluctuations in the expansion space of the refrigerant gas in the cold head 14 and pressure fluctuations of the refrigerant gas in the expansion space synchronized therewith, and the low-temperature section 14b of the cold head 14 is cooled to a desired cryogenic temperature. When the cold head 14 is, for example, of a two-stage type, the first cooling stage is cooled to a first cooling temperature in the range of, for example, about 30 K to about 80 K, and the second cooling stage is cooled to a second cooling temperature lower than the first cooling temperature, for example, 1 K to 20 K. The second cooling temperature may be the liquid helium temperature of about 4.2 K or a temperature lower than that.

[0029] 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 into the suction port 31 of the compressor 12. The refrigerant gas passes through the storage tank 36 on the suction passage 33 and is recovered to the suction port of the compressor body 16. The refrigerant gas is compressed and pressurized by the compressor body 16. At this time, the temperature of the refrigerant gas is raised by the heat of compression. The refrigerant gas discharged from the discharge port of the compressor body 16 is cooled by the refrigerant gas cooler 22a of the heat exchanger 22, and then passes through the oil separator 34 and the adsorber 35 to leave the compressor 12 from the discharge port 30. The refrigerant gas is supplied to the inside of the cold head 14 through the high pressure piping 42 and the high pressure port 40.

[0030] Fig. 2 is a schematic perspective view showing the appearance of the compressor 12 according to the embodiment. Figs. 3 and 4 are schematic perspective views showing the arrangement of internal equipment of the compressor 12 according to the embodiment. Figs. 2 and 3 show a perspective view of the compressor 12 seen from the front, and Fig. 4 shows a perspective view of the compressor 12 seen from the rear. Figs. 3 and 4 show a state in which some panels of the compressor housing 24 have been removed in order to show the arrangement of the internal equipment of the compressor 12.

[0031] 2, the compressor housing 24 of the compressor 12 has a rectangular parallelepiped shape with six faces, and includes a front panel 24a, a rear panel 24b, a top panel 24c, a bottom panel 24d, and two side panels 24e and 24f. The rear panel 24b faces the opposite side to the front panel 24a. Between the front panel 24a and the rear panel 24b, the top panel 24c is disposed above, the bottom panel 24d is disposed below, and the side panels 24e and 24f are disposed on the left and right.

[0032] The front panel 24a includes two panel portions that combine to form the front panel 24a, specifically a first panel portion 28 and a second panel portion 29. The first panel portion 28 provides plumbing connections and the second panel portion 29 provides a user interface and electrical connections. The second panel portion 29 is removably coupled to the first panel portion 28 as described below with reference to FIG.

[0033] The first panel portion 28 and the second panel portion 29 have a vertically elongated shape with a total length corresponding to the height of the compressor 12, and are adjacent to each other on the left and right in a front view. The first panel portion 28 corresponds to the right half of the front panel 24a, and the second panel portion 29 corresponds to the left half of the front panel 24a. These panel portions are thin plate-like members made of a metal such as stainless steel or other appropriate material.

[0034] 2 and 3, the first panel portion 28 is provided with the discharge port 30, the suction port 31, the cooling medium intake port 44, and the cooling medium discharge port 45. In this manner, the inlets and outlets for fluids such as refrigerant gas in the compressor 12 are concentrated in the first panel portion 28. The second panel portion 29 is not provided with such fluid inlets and outlets.

[0035] An operation panel 25 is provided on the front surface of the second panel portion 29 (the surface facing outside the compressor housing 24) for receiving inputs from a user of the cryogenic refrigerator 10 for controlling the cryogenic refrigerator 10 and / or for displaying information regarding the cryogenic refrigerator 10.

[0036] In addition, a power breaker 54 and a cold head connector 55 are provided on the front surface of the second panel portion 29. The power breaker 54 is connected to an external power source such as a commercial power source, thereby supplying power to the cryogenic refrigerator 10. Electrical wiring is connected to the cold head connector 55 for supplying power from the compressor 12 to the cold head 14 and for controlling the cold head 14 by the control panel 50. This electrical wiring establishes an electrical connection between the compressor 12 and the cold head 14.

[0037] The power breaker 54 is provided with a main switch 56. The main switch 56 is a switch for switching on and off the cryogenic refrigerator 10. When the main switch 56 is on, the compressor 12 and the cold head 14 are operated, and when the main switch 56 is off, the operation of the compressor 12 and the cold head 14 is stopped.

[0038] A control panel 50 is mounted on the second panel portion 29. The control panel 50 is attached to a rear surface of the second panel portion 29 (the surface facing the inside of the compressor housing 24) and is housed in the compressor housing 24. As will be described in detail later, the control panel 50 can be pulled out forward from the compressor housing 24 together with the second panel portion 29, as indicated by arrow A in Figures 3 and 4.

[0039] The control panel 50 is a control device that controls the compressor 12. The control panel 50 may include a control circuit configured to receive outputs from various sensors provided in the cryogenic refrigerator 10 and control various devices of the cryogenic refrigerator 10 based on the sensor outputs. A plurality of electrical components including sensors such as a temperature sensor and a pressure sensor may be housed in the compressor housing 24. Each sensor may be connected to the control panel 50 by a communication cable.

[0040] The 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, a coolant temperature sensor provided in the coolant piping of the heat exchanger 22, a cooling temperature sensor provided in the low-temperature section 14b of the cold head 14, and the like.

[0041] For example, as shown in FIG. 1, the first temperature sensor 46 is provided upstream of the heat exchanger 22 on the discharge flow passage 32 of the refrigerant gas line 18, and measures the temperature of the refrigerant gas flowing from the compressor body 16 to the heat exchanger 22. The second temperature sensor 47 is provided downstream of the heat exchanger 22 on the refrigerant gas line 18, and measures the temperature of the refrigerant gas flowing from the heat exchanger 22 to the oil separator 34. The third temperature sensor 48 is provided upstream of the heat exchanger 22 on the oil circulation line 20, and measures the temperature of the oil flowing from the compressor body 16 to the heat exchanger 22. The fourth temperature sensor 49 is provided downstream of the heat exchanger 22 on the oil circulation line 20, and measures the temperature of the oil flowing from the heat exchanger 22 to the compressor body 16. The temperature sensor is configured to output a signal representing the measured temperature to the control panel 50. The temperature sensor may be, for example, a thermistor. The temperature sensor may be attached to the outer surface of the piping constituting the refrigerant gas line 18 and the oil circulation line 20.

[0042] Also, a first pressure sensor 37a may be disposed 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 50. The second pressure sensor 37b is disposed 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 50.

[0043] The electrical components controlled based on the sensor output may include, for example, a compressor motor that drives the compressor main body 16, the bypass valve 38, and a cold head motor that drives the cold head 14. The control panel 50 may include a compressor inverter for controlling the rotation speed of the compressor motor and / or a cold head inverter for controlling the rotation speed of the cold head motor.

[0044] Referring again to FIG. 2 to FIG. 4, casters 52 are attached to the bottom panel 24d to facilitate the movement and transportation of the compressor 12. Four casters 52 are provided at the four corners of the bottom panel 24d. As shown in FIG. 3 and FIG. 4, a caster fixing portion 52a is provided at the upper end of the bottom panel 24d for each caster 52 in order to fix the caster 52 to the bottom panel 24d. As an example, the caster fixing portion 52a may include a nut that fixes the caster 52 to the bottom panel 24d. The caster 52 is provided with a bolt portion extending upward from the caster 52, and this bolt portion extends above the bottom panel 24d through a receiving hole penetrating the bottom panel 24d, and is fixed to the bottom panel 24d by the nut.

[0045] As shown in Fig. 3 and Fig. 4, the compressor housing 24 includes a frame structure 26 that supports the above-mentioned panels and provides structural strength. The panels are removably attached to the frame structure 26. When the panels are attached to the frame structure 26, the equipment inside the compressor 12 is covered and hidden by the panels, as shown in Fig. 2. The panels may be attached to the frame structure 26 by an appropriate method, such as by screw fastening. When the panels are removed from the frame structure 26, a user or worker can easily access the equipment inside the compressor 12 through the openings in the frame structure 26, and can efficiently perform maintenance or manufacturing work on the compressor 12.

[0046] For example, a rectangular rear outer frame 26a is provided on the rear surface of the compressor housing 24 so as to surround the rear surface and constitute a part of the frame structure 26. The rear panel 24b has four rectangular sides that are removably attached to the rear outer frame 26a. The upper ends of the rear outer frame 26a are connected to the upper end of the front panel 24a by two side frames 26b, and the lower part of the rear outer frame 26a is connected to the rear edge of the bottom panel 24d. The lower edge of the front panel 24a is connected to the front edge of the bottom panel 24d. The upper panel 24c has four sides that are removably attached to the rear outer frame 26a and the upper part of the front panel 24a and the two side frames 26b. The side panel 24e has four sides that are removably attached to the rear outer frame 26a, the side of the first panel portion 28, the side frames 26b, and the bottom panel 24d. The side panel 24f has its four sides removably attached to the rear outer frame 26a, the sides of the second panel portion 29, the side frame 26b, and the bottom panel 24d.

[0047] In existing compressors, the panels that form each side of the compressor housing are designed to provide structural strength, so the panels tend to be thick and heavy. Therefore, it is not easy to install the panels during the manufacturing process or to remove the panels during maintenance, which is one of the factors that reduces workability for workers. In contrast, according to the embodiment, the compressor housing 24 includes a frame structure 26 that provides structural strength, so that each panel, such as the back panel 24b attached to the frame structure 26, can be made thinner and lighter. Such a housing structure also contributes to improving workability.

[0048] As described above, the main components of the compressor 12, such as the compressor body 16, the heat exchanger 22, the oil separator 34, the adder 35, the storage tank 36, and the control panel 50, are housed in the compressor housing 24. The oil separator 34, the adder 35, and the storage tank 36 are installed on the bottom panel 24d in close proximity to one side panel 24e, and are arranged in the compressor housing 24. The adder 35, the storage tank 36, and the oil separator 34 are arranged in this order from the first panel portion 28 of the front panel 24a toward the rear panel 24b. The compressor body 16 and the control panel 50 are also arranged in close proximity to the other side panel 24f in the compressor housing 24. As described above, the control panel 50 is attached to the second panel portion 29 of the front panel 24a, and the compressor body 16 is installed on the bottom panel 24d between the control panel 50 and the rear panel 24b.

[0049] As shown in FIG. 4, the heat exchanger 22 is arranged in a spirally bent state along the rear surface of the compressor housing 24. This allows the double tubes of the heat exchanger 22, which have a relatively long overall length, to be compactly arranged and space-savingly arranged. The spiral shape of the heat exchanger 22 is formed so as to leave the center of the rear surface of the compressor housing 24 open. That is, an internal access opening 62 in which the heat exchanger 22 is not arranged is formed in the center of the rear surface of the compressor housing 24. In the manufacturing process of the compressor 12 or in maintenance work on the compressor 12 at the site where the compressor 12 is used, a worker can easily access the equipment inside the compressor 12 from the internal access opening 62. For example, manufacturing work such as pipe welding and joint fastening, and various maintenance work (for example, replacement of consumables such as filters, replacement of equipment such as broken sensors, repairs, etc.) can be performed through the internal access opening 62.

[0050] Fig. 5 is a plan view showing a schematic view of a portion of the front panel 24a according to the embodiment, and Fig. 6 is a side view showing a schematic view of a portion of the front panel 24a according to the embodiment.

[0051] As described above, the front panel 24a includes the first panel portion 28 and the second panel portion 29 that are removably connected to each other. The upper rear portions of these two panel portions are shown in Fig. 5. Note that Fig. 5 shows a state in which the remaining portions of the compressor housing 24, such as the frame structure 26 and the top panel 24c, have been removed from the front panel 24a, and the control panel 50 has been removed from the second panel portion 29.

[0052] The first panel portion 28 and the second panel portion 29 are removably connected by a connector 58. The connector 58 may be, for example, a fastener such as a screw, or a bolt and nut, or any other suitable removable connecting part. The first panel portion 28 has a first panel side surface 28a and a second panel side surface 28b, and the second panel portion 29 has a first panel side surface 29a and a second panel side surface 29b. The first panel side surface 28a of the first panel portion 28 and the first panel side surface 29a of the second panel portion 29 are in contact with each other and are connected by the connector 58. In this embodiment, the first panel portion 28 and the second panel portion 29 have a vertically elongated shape, and therefore may be connected by a plurality of connectors 58, for example, three connectors 58, along the longitudinal direction.

[0053] The second panel side surface 28b of the first panel portion 28 is the side opposite to the first panel side surface 28a, and faces the side panel 24e shown in Fig. 2. The second panel side surface 29b of the second panel portion 29 is the side opposite to the first panel side surface 29a, and faces the side panel 24f shown in Fig. 2.

[0054] The first panel portion 28 has an opening 60 that allows access to the connector 58 from outside the compressor housing 24. Specifically, this opening 60 is provided in the second panel side surface 28b of the first panel portion 28. A plurality of openings 60 may be provided in the second panel side surface 28b corresponding to a plurality of connectors 58. Since the connector 58 and the opening 60 are provided at the same position in the longitudinal direction (i.e., the height direction) of the panel, the opening 60 functions as a peephole, so to speak.

[0055] 6 shows an opening 60 and its vicinity in the second panel side surface 28b of the first panel portion 28. When looking into the opening 60 from outside the compressor housing 24, as shown in the figure, the connector 58 can be seen in the opening 60. In this example, the diameter of the opening 60 is slightly larger than the diameter of the connector 58, and the entire head of the connector 58 can be seen through the opening 60.

[0056] Thus, the opening 60 can be used to access the connector 58 from outside the compressor housing 24. As shown in FIG. 5, a tool 64 having a length that matches the width of the first panel portion 28 (the lateral dimension in FIG. 5) can be inserted into the compressor housing 24 through the opening 60 to reach the connector 58. If the connector 58 is a screw, the tool 64 can be, for example, a screwdriver. In this manner, the opening 60 and the tool 64 can be used to operate the connector 58 to connect or disconnect the first panel portion 28 and the second panel portion 29.

[0057] As described above, the compressor 12 includes various electrical components such as various sensors (for example, pressure sensors 37a, 37b and temperature sensors 46-49) and the bypass valve 38. These electrical components are housed in the compressor housing 24 and connected to the control panel 50. For electrical connection between the electrical components and the control panel 50, the control panel 50 includes a plurality of connectors 66, as shown in Figs. 4 and 7. Connectors of electrical wiring (not shown) extending from the electrical components are connected to these connectors 66.

[0058] FIG. 7 is a schematic plan view showing the rear face of the control panel 50 according to the embodiment. Referring to FIG. 4 and FIG. 7, a plurality of connectors 66 are provided on the rear face of the control panel 50. These connectors may be arranged in a concentrated manner at a specific location on the rear face of the control panel 50. For example, as shown in the figure, a large number of connectors 66 may be arranged in a concentrated manner at a location on the rear face of the control panel 50 near the outer side of the compressor housing 24 (e.g., a location close to the panel of the compressor housing 24). In this way, the connectors 66 are exposed near the opening of the frame structure 26 when a panel (e.g., the side panel 24f) is removed from the compressor housing 24. An operator can easily access these connectors 66 from outside the compressor housing 24, and can easily perform the operation of connecting (or disconnecting) electrical components to the connectors 66.

[0059] As shown in the figure, the rear surface of the control panel 50 is provided with a number of fasteners 68 (e.g., tie anchors) for removably fixing the electrical wiring that connects the electrical components to the connectors 66 to the control panel 50. The fasteners 68 are provided so as to define a wiring route 70 (an example is shown by a dashed line in FIG. 7) on the rear surface of the control panel 50. By using these fasteners 68, the electrical wiring can be arranged in an organized manner on the rear surface of the control panel 50.

[0060] Fig. 8 is a schematic top view showing the pass zone 72 of the control panel 50 according to the embodiment. As described above, the control panel 50 can be pulled out forward from the compressor housing 24 together with the second panel portion 29. When the control panel 50 is pulled out, it is taken out forward from the compressor housing 24 along the arrow A. Note that in Fig. 8, components of the compressor 12 other than the control panel 50 are omitted from the illustration.

[0061] A caster fixing portion 52a is provided at the top end of the bottom panel 24d of the compressor housing 24. In this embodiment, a pass area 72 of the control panel 50 when the control panel 50 is pulled forward from the compressor housing 24 together with the second panel portion 29 is determined to be inside the caster fixing portion 52a. In other words, the width (horizontal dimension) W1 of the bottom surface of the control panel 50 is narrower than the width W2 of the second panel portion 29. This prevents interference between the control panel 50 and the caster fixing portion 52a when the control panel 50 is pulled forward, and allows the control panel 50 to be smoothly removed.

[0062] An exemplary procedure for removing the control panel 50 according to the embodiment from the compressor 12 is as follows. First, the side panels 24e, 24f and the top panel 24c are removed from the compressor housing 24. The second panel portion 29 of the front panel 24a is released from the frame structure 26 and the bottom panel 24d. A long tool 64, such as a screwdriver, is inserted through the opening 60 of the first panel portion 28 of the front panel 24a to remove the connector 58 and release the fastening between the first panel portion 28 and the second panel portion 29. In this manner, the structural connection between the compressor 12 and the control panel 50 is released.

[0063] It is not necessary to remove the main components of the compressor 12, such as the compressor body 16, the oil separator 34, the adsorber 35, and the storage tank 36, which are installed on the bottom panel 24d.

[0064] Next, the compressor 12 is electrically disconnected from the control panel 50. The electrical wiring connected to the multiple connectors 66 on the rear surface of the control panel 50 is removed. These wirings are also removed from the fasteners 68 on the rear surface of the control panel 50. In addition, the electrical cable connecting the compressor main body 16 to the control panel 50 is also removed.

[0065] Then, the second panel portion 29 and the control panel 50 are pulled out from the compressor housing 24 along the arrow A. In this manner, the control panel 50 can be removed from the compressor 12 together with the second panel portion 29. The removed control panel 50 can be subjected to maintenance work such as repair or replacement.

[0066] As mentioned at the beginning of this document, existing compressors for cryogenic refrigerators typically use a single panel on the front of the compressor housing. The single front panel can be connected to the refrigerant gas supply and return piping to the cold head. In addition, the front panel can also be connected to the coolant supply and return piping to a heat exchanger installed in the compressor housing to cool the compressor. The compressor control panel can be located behind the front panel in the compressor housing. In compressors of this design, an operator must first remove the front panel from the compressor housing to remove the control panel. However, before removing the front panel, the refrigerant gas must be drained from the refrigerant gas piping and the coolant must be drained from the coolant liquid piping, and then these pipings must be removed from the front panel. In some cases, other compressor components, such as an addor, are fastened to the front panel, and in that case, they must also be removed from the front panel first. Therefore, in existing designs, the removal of the control panel from the compressor requires a preliminary process, as if the compressor were disassembled into individual parts, which is quite time-consuming.

[0067] In contrast, according to the embodiment, the first panel portion 28 of the front panel 24a provides the piping connection, and the control panel 50 is mounted on the second panel portion 29. This allows the second panel portion 29 to be removed without removing the first panel portion 28 from the compressor housing 24, with the piping for the refrigerant gas and the cooling liquid remaining connected to the first panel portion 28. This makes it unnecessary to remove the piping when removing the control panel 50. This makes it easier to remove the control panel 50 from the compressor 12 for the cryogenic refrigerator 10.

[0068] In addition, the first panel portion 28 is provided with an opening 60 that allows access to the connector 58 from outside the compressor housing 24. This allows a tool 64 to reach the connector 58 from outside the compressor housing 24 and release the connection between the first panel portion 28 and the second panel portion 29 without removing various devices, such as the adsorber 35, installed inside the compressor housing 24. This also helps to facilitate the removal of the control panel 50.

[0069] A plurality of connectors 66 connected to a plurality of electrical components are provided on the rear surface of the control panel 50. Preferably, the plurality of connectors 66 are concentrated in a specific location on the rear surface of the control panel 50. This allows the control panel 50 and the electrical components to be disconnected by removing the wiring from the connectors 66.

[0070] In addition, the control panel 50 can be pulled out forward from the compressor housing 24 together with the second panel portion 29. The passage area 72 of the control panel 50 is defined inside the caster fixing portion 52a. This allows the control panel 50 to be pulled out forward without interfering with the caster fixing portion 52a.

[0071] The present invention has been described above based on examples. It will be understood by those skilled in the art that the present invention is not limited to the above-described embodiments, that various design changes are possible, that various modifications are possible, and that such modifications are also within the scope of the present invention. Various features described in relation to one embodiment can also be applied to other embodiments. A new embodiment resulting from a combination has the combined effects of each of the combined embodiments.

[0072] In the above embodiment, the front panel 24a is formed from two panel parts adjacent to the left and right, but the front panel 24a may have other configurations. For example, the front panel 24a may be formed from two panel parts adjacent to each other vertically. In this case, the first panel part 28 and the second panel part 29 may have a horizontally elongated shape having a total length corresponding to the width of the compressor 12 and may be adjacent to each other vertically when viewed from the front. The first panel part 28 (or the second panel part 29) may correspond to the upper half of the front panel 24a, and the second panel part 29 (or the first panel part 28) may correspond to the lower half of the front panel 24a.

[0073] The front panel 24a may be divided into three or more panel portions, including a first panel portion 28 and a second panel portion 29. These panel portions may be connected to each other to form the front panel 24a.

[0074] The present invention has been described using specific terms based on the embodiments, but the embodiments merely show one aspect of the principles and applications of the present invention, and many modifications and changes in arrangement are permitted to the embodiments without departing from the spirit of the present invention as defined in the claims. [Explanation of symbols]

[0075] 10 cryogenic refrigerator, 12 compressor, 24 compressor housing, 24a front panel, 24d bottom panel, 28 first panel portion, 28a first panel side surface, 28b second panel side surface, 29 second panel portion, 50 control panel, 52 caster, 52a caster fixing portion, 58 connecting device.

Claims

1. A control panel and a compressor housing having a front panel and housing the control panel; The front panel comprises a first panel portion providing piping connections, and a second panel portion removably connected to the first panel portion and mounting the control panel.

2. the second panel portion is removably connected to the first panel portion by a connector; 2. The compressor for a cryogenic refrigerator according to claim 1, wherein the first panel portion has an opening that allows access to the connector from outside the compressor housing.

3. 3. The compressor for a cryogenic refrigerator according to claim 2, wherein the first panel portion includes a first panel side surface to which the connector is attached and a second panel side surface having the opening.

4. 2. The compressor for a cryogenic refrigerator according to claim 1, wherein the control panel can be pulled out forward from the compressor housing together with the second panel portion.

5. The compressor housing includes a bottom panel, and a caster fixing portion is provided on an upper end portion of the bottom panel, The compressor for a cryogenic refrigerator according to claim 4, characterized in that a passage area of ​​the control panel when the control panel is pulled forward together with the second panel portion from the compressor housing is defined inside the caster fixing portion.

6. The compressor further includes a plurality of electrical components housed in the compressor housing, 6. The compressor for a cryogenic refrigerator according to claim 1, wherein the control panel is provided on a rear surface thereof with a plurality of connectors for connection to the plurality of electrical components.

7. 7. The compressor for a cryogenic refrigerator according to claim 6, wherein the plurality of connectors are collectively arranged at a specific location on the rear surface of the control panel.

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