Cryogenic refrigerator

Abstract

A cryogenic refrigerator (100) is provided with: a cold head (104) that can be mounted on a vacuum container (20); a cold head mount (106) configured to connect the cold head (104) to the vacuum container (20) so as to allow the cold head (104) to move relative to the vacuum container (20); a flexible conduit (108) connected to the cold head (104) outside the vacuum container (20); and a flexible conduit holder (110) configured so as to fix and hold the flexible conduit (108) with respect to the vacuum container (20).

Description

Technical Field

[0001] The invention relates to an ultra-low temperature refrigerator. Background Art

[0002] In order to provide ultra-low temperature cooling for various cooling objects (e.g., cooling of superconducting devices, condensation of ultra-low temperature liquids such as liquid helium, etc.), ultra-low temperature refrigerators represented by Gifford-McMahon (GM) refrigerators are often used. In the past, it was known that such an ultra-low temperature refrigerator was set on a cryostat via a bellows, and a thermal switch was used to thermally connect the ultra-low temperature refrigerator to the cooling object in the cryostat or disconnect its thermal connection by using the up and down movement of the ultra-low temperature refrigerator accompanied by the expansion and contraction of the bellows.

[0003] Previous technical literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-211803 Summary of the invention

[0006] Technical issues to be solved by the invention

[0007] When the above-mentioned form of thermal switch is turned on (i.e., the ultra-low temperature refrigerator is thermally connected to the cooling object), the ultra-low temperature refrigerator can be rigidly fixed to the cryostat, while when the thermal switch is closed (i.e., the ultra-low temperature refrigerator is temporarily separated from the cooling object), the ultra-low temperature refrigerator is usually supported on the cryostat with low rigidity, for example due to the flexibility of the bellows.

[0008] When the cryogenic refrigerator is operated on site, various pipes or wiring such as flexible hoses for supplying or discharging working gas or cables for power supply are connected to the cryogenic refrigerator and extend around the cryogenic refrigerator. As one of the risks that can be imagined in the general setting of such a cryogenic refrigerator, for example, when the feet of a worker passing near the cryogenic refrigerator are caught by these pipes and tripped, an unexpected large external force from the pipes may act on the cryogenic refrigerator, which is worrying. Such unexpected external forces may cause problems especially when the thermal switch is in the off state. Due to the external force, the position and posture of the cryogenic refrigerator will be disturbed, so it will interfere with or collide with the surrounding structures. In the worst case, the cryogenic refrigerator or its supporting structure may be damaged.

[0009] One of the exemplary purposes of an embodiment of the present invention is to protect a cryogenic refrigerator from unexpected external forces.

[0010] Means for solving technical problems

[0011] According to one embodiment of the present invention, an ultra-low temperature refrigerator comprises: a cold head capable of being mounted on a vacuum container; a cold head mounting seat configured to connect the cold head to the vacuum container in a manner allowing the cold head to move relative to the vacuum container; a flexible pipeline connected to the cold head outside the vacuum container; and a flexible pipeline retaining member configured to fix and retain the flexible pipeline relative to the vacuum container.

[0012] Effects of the Invention

[0013] According to the present invention, a cryogenic refrigerator can be protected from unexpected external forces. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a diagram schematically showing a cryogenic device according to an embodiment.

[0015] Figure 2 This is a diagram schematically showing a working gas pipeline of a cryogenic refrigerator according to a comparative example.

[0016] Figure 3 It is a rough representation of the application Figure 1 A diagram of exemplary electrical connections for a cryogenic refrigerator is shown.

[0017] Figure 4 It is a rough representation of the application Figure 1 A diagram of an exemplary drive source for a cryogenic refrigerator is shown. DETAILED DESCRIPTION

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description and the accompanying drawings, identical or equivalent components, parts, and processes are marked with the same symbols, and repeated descriptions are appropriately omitted. In each of the drawings, for the convenience of description, the scale or shape of each part is appropriately set, and unless otherwise specifically mentioned, it is not interpreted as a limitative. The embodiments are illustrative and do not limit the scope of the present invention in any way. All features or combinations thereof described in the embodiments are not necessarily the essence of the invention.

[0019] Figure 1 1 is a diagram schematically showing a cryogenic device 10 according to an embodiment. In this embodiment, the cryogenic device 10 can be used as a cryogenic liquid storage device. Therefore, the cryogenic device 10 includes, for example, a vacuum container 20 for storing liquid hydrogen or other cryogenic liquids 12 and a cryogenic refrigerator 100 for cooling the stored cryogenic liquid 12 to a cryogenic temperature below its liquefaction temperature (approximately -253°C (20K) in the case of liquid hydrogen).

[0020] The vacuum container 20 includes an outer tank 22 and an inner tank 24. A vacuum insulation layer 26 is formed between the outer tank 22 and the inner tank 24. The outer tank 22 is configured to isolate the vacuum insulation layer 26 from the surrounding environment (e.g., room temperature atmospheric pressure environment) of the ultra-low temperature device 10. In addition, the inner tank 24 is configured to isolate its internal volume from the vacuum insulation layer 26. The ultra-low temperature liquid 12 is contained in the inner tank 24. The outer tank 22 and the inner tank 24 are formed of metal materials such as stainless steel or other suitable high-strength materials to withstand the pressure difference between the inside and the outside.

[0021] In the vacuum insulation layer 26, an insulation structure 28 including an insulation support body 28a and an insulation layer 28b may be arranged. The insulation support body 28a is formed of a hard material having insulation properties, such as fiber reinforced plastic, and is configured to support the inner tank 24 on the outer tank 22. The insulation layer 28b may include a multilayer insulation material (multilayer insulation (MLI)). In addition to the insulation layer 28b, the vacuum insulation layer 28 may also include a granular or other shaped insulation material (e.g., granular perlite) filled in the vacuum insulation layer 26, or the vacuum insulation layer 28 may include a granular or other shaped insulation material (e.g., granular perlite) filled in the vacuum insulation layer 26 instead of the insulation layer 28b.

[0022] The inner tank 24 is provided with a recondensation portion 30 disposed on the tank wall thereof. The recondensation portion 30 is cooled from the outside of the inner tank 24 by the ultra-low temperature refrigerator 100. The recondensation portion 30 has a heat transfer surface 30a exposed to the outside of the inner tank 24 and in contact with the ultra-low temperature refrigerator 100. In order to increase the surface area in contact with the ultra-low temperature liquid 12 or the vaporized ultra-low temperature liquid 12, the recondensation portion 30 may have a fin-shaped protrusion or concave-convex inside the inner tank 24. The recondensation portion 30 is formed, for example, of pure copper (for example, oxygen-free copper, tough copper, etc.) or other high thermal conductivity metals.

[0023] The cryogenic refrigerator 100 includes a compressor 102 , a cold head 104 that can be mounted on a vacuum container 20 , and a cold head mounting base 106 that connects the cold head 104 to the vacuum container 20 so as to allow the cold head 104 to move relative to the vacuum container 20 .

[0024] The compressor 102 is configured to recover the working gas of the cryogenic refrigerator 100 from the cold head 104, and to supply the working gas to the cold head 104 again after increasing the pressure of the recovered working gas. The cold head 104 is also called an expander or a refrigerator. The compressor 102 and the cold head 104 constitute a refrigeration cycle of the cryogenic refrigerator 100, whereby the cryogenic refrigerator 100 provides cryogenic cooling. The working gas is also called a refrigerant gas, which is usually helium, but other suitable gases may also be used.

[0025] In this embodiment, the cryogenic refrigerator 100 is a single-stage GM refrigerator. Therefore, the cold head 104 includes a cooling stage 104a, a cylinder 104b, a drive unit 104c and a cold head flange 104d. The cooling stage 104a is formed, for example, of pure copper (for example, oxygen-free copper, tough copper, etc.) or other high thermal conductivity metals. During the operation of the cryogenic refrigerator 100, the cooling stage 104a is cooled to a desired ultra-low temperature, for example, within a temperature range below the liquefaction temperature of the cryogenic liquid 12. When the cryogenic liquid 12 is liquid hydrogen, the cooling stage 104a is cooled to a cooling temperature included in a temperature range of, for example, 10K to 30K (for example, a cooling temperature near 20K such as 20K±1K, or 20K±2K or 20K±5K).

[0026] The cylinder 104b connects the cooling stage 104a to the cold head flange 104d. Figure 1 A displacer (not shown) for controlling the volume of the expansion space of the working gas adjacent to the cooling stage 104a is configured in a manner that allows the cylinder 104b to move in the vertical direction (in the vertical direction). The cylinder 104b and the cold head flange 104d are usually formed of a suitable metal material such as stainless steel. The drive unit 104c is installed on the cold head flange 104d on the side opposite to the cylinder 104b. The drive unit 104c is provided with a cold head drive motor 104e such as an electric motor for driving the displacer in the cylinder 104b and a pressure control mechanism (not shown) such as a rotary valve for controlling the pressure of the working gas in the expansion space in the cylinder 104b.

[0027] like Figure 1 As shown, an installation port 32 for installing the cold head 104 in the vacuum container 20 is provided in the outer groove 22 of the vacuum container 20. When installing, the cold head 104 is inserted into the vacuum container 20 from the installation port 32 and detachably installed in the installation port 32 via the cold head mounting seat 106. The cold head 104 is installed in the vacuum container 20 in such a manner that the cooling stage 104a is arranged on the vacuum insulation layer 26 in the vacuum container 20 and the driving part 104c is arranged outside the vacuum container 20.

[0028] As an example, the mounting port 32 is formed on the top plate or the upper part of the vacuum container 20. The cold head 104 is arranged on the vacuum container 20 in such a manner that the central axis thereof is aligned with the vertical direction. However, the position of the mounting port 32 and the mounting posture of the cold head 104 are not limited thereto. For example, the mounting port 32 may also be formed on the bottom plate or the lower part of the vacuum container 20. The cold head 104 can be arranged in a desired posture and can be arranged on the vacuum container 20 in such a manner that the central axis thereof is aligned with the inclined direction or the horizontal direction.

[0029] The cold head mounting seat 106 includes a mounting flange 106a that can be mounted on the vacuum container 20 and a retractable airtight partition wall 106b that connects the cold head 104 to the mounting flange 106a. The mounting flange 106a is fixed to the mounting port 32 of the vacuum container 20 using, for example, fastening components such as bolts or other appropriate fixing members. In addition, the mounting flange 106a can also be fixed to the vacuum container 20 via a connecting component, instead of being directly fixed to the vacuum container 20 as shown in the figure. The retractable airtight partition wall 106b is, for example, a bellows, which connects the cold head flange 104d to the mounting flange 106a. Therefore, the mounting port 32 is closed by the mounting flange 106a, the airtight partition wall 106b and the cold head flange 104d, and the airtightness of the vacuum container 20 is maintained.

[0030] The mounting flange 106a has an opening at the center, and the telescopic airtight partition 106b is formed in a cylindrical shape. The cylinder 104b of the cold head 104 extends from the cold head flange 104d through the inside of the telescopic airtight partition 106b and the opening of the mounting flange 106a to the inside of the vacuum container 20.

[0031] In addition, the cold head mounting base 106 includes a driving source 106c, which is mounted on the cold head mounting base 106 and moves the cold head 104 relative to the vacuum container 20. The driving source 106c can be configured to move the cold head 104 using appropriate power such as air pressure, hydraulic pressure, electric motor, electromagnet, etc., or can also be configured to be able to move the cold head 104 manually.

[0032] The driving source 106c is provided on the mounting flange 106a and connected to the cold head flange 104d so as to move the cold head flange 104d along the expansion and contraction direction of the airtight partition 106b. Therefore, by operating the driving source 106c, the airtight partition 106b can be expanded and contracted while the cold head flange 104d can be moved relative to the mounting flange 106a. Figure 1 In the example shown, the driving source 106 c is capable of raising and lowering the cold head flange 104 d relative to the mounting flange 106 a (ie, the cold head 104 relative to the vacuum container 20 ).

[0033] In this way, the cold head mounting base 106 can act as a thermal switch to thermally connect the cold head 104 to the storage tank of the ultra-low temperature liquid 12 (ie, the inner tank 24 of the vacuum container 20) or to disconnect the thermal connection. Figure 1In the figure, the state in which the thermal switch is turned on is shown by a solid line, and the state in which the thermal switch is turned off is shown by a dotted line. When the thermal switch is turned on, the cooling stage 104a of the cold head 104 contacts the heat transfer surface 30a of the recondensation section 30 of the inner tank 24. Thus, the cooling stage 104a can cool the recondensation section 30 to the liquefaction temperature of the ultra-low temperature liquid 12, and can keep the ultra-low temperature liquid 12 in the inner tank 24 and can recondense the vaporized ultra-low temperature liquid 12. On the other hand, if the cold head 104 is lifted by the operation of the driving source 106c, the cooling stage 104a is separated from the heat transfer surface 30a of the recondensation section 30. Since the cooling stage 104a is arranged on the vacuum insulation layer 26, the thermal contact between the cooling stage 104a and the recondensation section 30 is released. At this time, the cold head 104 does not cool the inner tank 24.

[0034] Such a thermal switch is conducive to improving the energy saving of the ultra-low temperature device 10. As an exemplary application of the ultra-low temperature refrigerator 100, it can be considered to stop the cooling operation of the ultra-low temperature refrigerator 100 when the vacuum container 20 is fully cooled. At this time, if the cold head 104 is in contact with the inner tank 24 of the vacuum container 20, the cold head 104 will become a heat transfer path from the surrounding environment of the ultra-low temperature device 10 to the inner tank 24, which may cause unwanted heat to invade the ultra-low temperature liquid 12. In contrast, when the ultra-low temperature refrigerator 100 is stopped, the cold head 104 is disconnected from the inner tank 24 by using a thermal switch, which can shield such intrusive heat.

[0035] In order to switch the thermal switch, a sensor 34 for detecting the physical quantity of the ultra-low temperature liquid 12 can be provided on the ultra-low temperature device 10. The driving source 106c can be configured to receive an output signal representing the detected physical quantity of the ultra-low temperature liquid 12 from the sensor 34, and move the cold head 104 according to the detected physical quantity of the ultra-low temperature liquid 12.

[0036] For example, the sensor 34 may be configured to be disposed in the inner tank 24 of the vacuum container 20, and to measure the internal pressure of the inner tank 24. The sensor 34 measures the vapor pressure of the ultra-low temperature liquid 12 in the inner tank 24. The driving source 106c may operate as follows: compare the measured pressure with the pressure threshold, and when the measured pressure exceeds the pressure threshold, turn on the thermal switch, and when the measured pressure is lower than the pressure threshold, turn off the thermal switch. In this way, the internal pressure of the inner tank 24 can be maintained at an appropriate pressure equivalent to the pressure threshold.

[0037] Alternatively, the sensor 34 may also be configured to measure the temperature of the ultra-low temperature liquid 12. In this case, the sensor 34 may be disposed in the inner tank 24, or may be disposed in the recondensation portion 30 of the inner tank 24. The drive source 106c may operate as follows: the measured temperature is compared with the temperature threshold, and when the measured temperature exceeds the temperature threshold, the thermal switch is set to be turned on, and when the measured temperature is lower than the temperature threshold, the thermal switch is set to be turned off. In this way, the ultra-low temperature liquid 12 can be maintained at an appropriate temperature equivalent to the temperature threshold.

[0038] Furthermore, the cryogenic refrigerator 100 includes a flexible tube 108 connected to the cold head 104 outside the vacuum container 20 and a flexible tube holder 110 configured to fix and hold the flexible tube 108 relative to the vacuum container 20. The flexible tube 108 connects the driving unit 104c of the cold head 104 to an external element (for example, the compressor 102) arranged outside the vacuum container 20. The flexible tube holder 110 is fixed to the mounting flange 106a of the cold head mounting seat 106, and holds the flexible tube 108 on the way from the cold head 104 to the external element. In other words, the flexible tube holder 110 is equivalent to a relay point that fixes the flexible tube 108 to the vacuum container 20.

[0039] The compressor 102 may be disposed at a location away from the cold head 104 and the vacuum container 20, for example, in a room or region different from the room or region where the cold head 104 and the vacuum container 20 are disposed, and the length of the flexible pipe 108 may be, for example, more than 10 m. The flexible pipe holder 110 is fixed to the mounting flange 106 a, so that the flexible pipe 108 is held at the end of the flexible pipe 108 on the cold head 104 side (for example, the end of the flexible pipe 108 within 10% or within 5% of the total length of the flexible pipe 108).

[0040] In this embodiment, the flexible pipe 108 includes a working gas pipe for supplying working gas to the cold head 104 or discharging working gas from the cold head 104, more specifically, a gas supply pipe 112 and a gas recovery pipe 114. The gas supply pipe 112 connects the working gas discharge port 102a of the compressor 102 to the high-pressure port 116a of the cold head 104, and the gas recovery pipe 114 connects the working gas intake port 102b of the compressor 102 to the low-pressure port 116b of the cold head 104.

[0041] Therefore, the working gas of the cryogenic refrigerator 100 is supplied from the compressor 102 to the cold head 104 through the gas supply line 112, and is recovered from the cold head 104 to the compressor 102 through the gas recovery line 114. As is well known, the pressure of the working gas in the gas supply line 112 and the pressure of the working gas in the gas recovery line 114 are both much higher than the atmospheric pressure, and can be referred to as the first high pressure and the second high pressure, respectively. For ease of explanation, the first high pressure and the second high pressure are also referred to as high pressure and low pressure, respectively. Typically, the high pressure is, for example, 2 to 3 MPa. The low pressure is, for example, 0.5 to 1.5 MPa, for example, about 0.8 MPa.

[0042] The flexible pipe holder 110 may include a working gas pipe holder for holding such a working gas pipe. The flexible pipe holder 110 may include a first holder for holding a gas supply pipe 112 and a second holder for holding a gas recovery pipe 114, and these two holders may be fixed to the mounting flange 106a. The flexible pipe holder 110 may be rigidly fixed to the mounting flange 106a, for example, by screwing, welding, or other appropriate fixing methods.

[0043] The two retainers may be arranged in a horizontal row on the mounting flange 106a, or may be arranged on the mounting flange 106a to sandwich the driving portion 104c, or may be arranged at any other position on the mounting flange 106a. Figure 1 In the example shown, the flexible pipe holder 110 is mounted on the upper surface of the mounting flange 106 a , but may be mounted on the lower surface of the mounting flange 106 a or other locations.

[0044] The gas supply line 112 includes a first portion 112a extending from a high-pressure port 116a of the cold head 104 and a second portion 112b extending from a working gas discharge port 102a of the compressor 102. The flexible line holder 110 may be configured as an intermediate joint having an internal flow path through which the working gas of the cryogenic refrigerator 100 can flow. For example, the first holder may be a first intermediate joint having a first internal flow path. At this time, one end of the first portion 112a of the gas supply line 112 is connected to the first holder, and the other end is connected to the high-pressure port 116a. One end of the second portion 112b of the gas supply line 112 is connected to the first holder, and the other end is connected to the working gas discharge port 102a. In this way, the high-pressure working gas discharged from the working gas discharge port 102a flows into the cold head 104 after passing through the second portion 112b, the first holder, and the first portion 112a.

[0045] Similarly, the gas recovery line 114 includes a first portion 114a extending from the low pressure port 116b of the cold head 104 and a second portion 114b extending from the working gas suction port 102b of the compressor 102. The flexible pipe holder 110 may be configured as an intermediate joint having an internal flow path through which the working gas of the ultra-low temperature refrigerator 100 can flow. For example, the second holder may be a second intermediate joint having a second internal flow path. At this time, one end of the first portion 114a of the gas recovery line 114 is connected to the second holder, and the other end is connected to the low pressure port 116b. One end of the second portion 114b of the gas recovery line 114 is connected to the second holder, and the other end is connected to the working gas suction port 102b. In this way, the low-pressure working gas flowing out of the low pressure port 116b of the cold head 104 is recovered to the compressor 102 after passing through the first portion 114a, the second holder, and the second portion 114b.

[0046] The gas supply line 112 and the gas recovery line 114 may be flexible pipes such as flexible hoses, and may be detachable from the compressor 102, the cold head 104, and the flexible pipe 108, for example, to facilitate replacement after damage.

[0047] Figure 2 FIG. 2 is a diagram schematically showing a working gas pipeline of a cryogenic refrigerator according to a comparative example. Figure 2 As shown, the cryogenic refrigerator 200 includes a compressor 202 and a cold head 204. The compressor 202 and the cold head 204 are connected by a flexible hose 206. The cold head 204 is mounted on the vacuum container 20 in a manner that allows it to move (rise and fall) relative to the vacuum container 20. The cold head 204 can act as a thermal switch that thermally connects the cold head 204 to the object to be cooled 208 or disconnects its thermal connection by the lifting. Figure 2 , the state where the thermal switch is closed is shown, that is, the cold head 204 is separated from the object to be cooled 208.

[0048] There is a possibility that a worker passing by the ultra-low temperature refrigerator 200 may trip over his or her foot 210 being caught by the flexible hose 206. In this case, the caught foot 210 will instantly pull the flexible hose 206 with great force, and a strong lateral load 212 may act on the cold head 204. When the thermal switch is closed, the cold head 204 is supported on the vacuum container 20 by a relatively low-rigidity support structure such as a bellows. Figure 2As shown by the black arrow 214 and the dotted line in the figure, the lateral load 212 will disturb the position and posture of the cryogenic refrigerator 200, and depending on the situation, the cryogenic refrigerator 200 may collide with surrounding structures such as the vacuum container 20 or the object to be cooled 208. As a result, the cryogenic refrigerator 200 or surrounding structures may be damaged.

[0049] In contrast, according to an embodiment, the flexible tube 108 is fixed and held in the vacuum container 20 by a flexible tube holder 110. Regarding the second portion (e.g., 112b, 114b) of the flexible tube 108 on the side away from the cold head 104, there is still a risk of tripping the feet of the staff. However, even if such a situation occurs, the pulling force acting on the second portion is only borne by the mounting flange 106a and the vacuum container 20 to which the flexible tube holder 110 is fixed. The pulling force is not directly transmitted to the cold head 104, and even if the thermal switch is in the off state, it can be expected that the position and posture of the cold head 104 can be maintained. In this way, the ultra-low temperature refrigerator 100 can be protected from unexpected external forces.

[0050] Figure 3 It is a rough representation of the application Figure 1 100. The flexible tube 108 may be a power supply cable for supplying power to the cold head 104. The power supply cable connects a power supply 118 disposed outside the vacuum container 20 to a drive unit 104c (e.g., Figure 1 In the exemplary configuration, the compressor 102 may also be used as the power source 118.

[0051] The flexible conduit holder 110 may also be a cable holder that is fixed to the mounting flange 106a and holds the power supply cable. In the example shown in the figure, the flexible conduit holder 110 is mounted on the mounting flange 106a in a manner that penetrates the mounting flange 106a. Thus, the power supply cable can be guided from a surface on one side (e.g., the upper surface) of the mounting flange 106a to a surface on the opposite side (e.g., the lower surface). Compared with the case where the power supply cable is arranged only on the upper surface side of the mounting flange 106a, the degree of freedom in arranging the power supply cable can be increased.

[0052] So, also with reference Figure 1 and Figure 2 The embodiment described above can protect the cryogenic refrigerator 100 from unexpected external forces. That is, even if an unexpected external force acts on the second portion of the flexible tube 108 extending from the flexible tube holder 110 to the power source 118, the external force can be borne by the mounting flange 106a and the vacuum container 20 to which the flexible tube holder 110 is fixed. The adverse effects of the external force on the cold head 104 can be reduced.

[0053] In addition, the flexible pipe retainer 110 of the type penetrating the mounting flange 106a as described above can also be used as a reference. Figure 1 A holder for a working gas line is described.

[0054] Figure 4 It is a rough representation of the application Figure 1 FIG. 1 is a diagram of an exemplary drive source of a cryogenic refrigerator 100 shown in FIG. The drive source 106c is mounted on a plate-shaped support body 120 disposed above the cold head 104. The drive source 106c includes a movable piston 122 that penetrates the support body 120 and protrudes downward. A plurality of (e.g., four) guide rods 124 are erected on the mounting flange 106a in a manner surrounding the cold head 104, and the support body 120 is fixed to the ends of the guide rods 124. The guide rods 124 penetrate the cold head flange 104d in the up-down direction, and the cold head flange 104d can move in the up-down direction along the guide rods 124.

[0055] Furthermore, a movable frame 126 including a support column 126a and a movable plate 126b is provided on the cold head flange 104d. The support column 126a is vertically provided on the cold head flange 104d, and the movable plate 126b is fixed to the support column 126a in a manner of bridging the ends of the support column 126a. The lower end of the movable piston 122 is fixed to the movable plate 126b.

[0056] Therefore, when the movable piston 122 moves forward and backward up and down by the operation of the driving source 106c, the cold head flange 104d can also move up and down via the movable frame 126. At this time, the cold head flange 104d moves up and down along the guide rod 124 while extending and retracting the airtight partition wall 106b. In this way, the driving source 106c can provide movement of the cold head 104 relative to the vacuum container 20.

[0057] The cryogenic refrigerator 100 may include another flexible pipe 128 connected to the driving source 106c and another flexible pipe holder 130 configured to fix and hold the other flexible pipe 128 relative to the vacuum container 20. The driving source 106c may be, for example, a cylinder, and in this case, the flexible pipe 128 may be a compressed air pipe for supplying compressed air to the driving source 106c or discharging compressed air from the driving source 106c. The flexible pipe holder 130 may be a holder fixed to the mounting flange 106a and holding the compressed air pipe.

[0058] In this way, the cryogenic refrigerator 100 can also be protected from unexpected external forces. That is, even if an unexpected external force acts on the second portion of the flexible tube 128 extending from the flexible tube holder 130 to the compressed air source 132, the external force can be borne by the mounting flange 106a to which the flexible tube holder 130 is fixed and the vacuum container 20. The adverse effects of the external force on the cold head 104 can be reduced.

[0059] The present invention is described above based on the embodiments. The present invention is not limited to the above-mentioned embodiments. It should be understood by those skilled in the art that the present invention can be subjected to various design changes and various variations, and such variations are also within the scope of the present invention. Various features described in one embodiment can also be applied to other embodiments. The new embodiment generated by the combination has the effects of each of the combined embodiments.

[0060] In the above embodiment, the working gas pipeline retainer is an example of an intermediate joint, but other structures can also be used. For example, the working gas pipeline retainer can also be a suitable fixing tool such as a hose clamp for holding the working gas pipeline, and such a fixing tool can be fixed on the mounting flange 106a. In this case, it is not necessary to divide the working gas pipeline with a retainer (the working gas pipeline does not need to be divided into the first part and the second part, and can be a flexible hose).

[0061] In the above embodiment, the flexible pipe holder 110 is fixed to the mounting flange 106a of the cold head mounting seat 106, but other structures may be adopted. For example, the flexible pipe holder 110 may also be directly fixed to the vacuum container 20. For example, the flexible pipe holder 110 may also be fixed to the wall surface of the vacuum container 20 where the mounting flange 106a (i.e., the mounting port 32 is provided) is installed or other parts of the vacuum container 20.

[0062] In the above embodiment, the case where the ultra-low temperature refrigerator 100 is a single-stage GM refrigerator is illustrated, but other structures may also be used. For example, the ultra-low temperature refrigerator 100 may also be a two-stage GM refrigerator. In this case, the ultra-low temperature refrigerator 100 can provide ultra-low temperature cooling below about 4K, and the ultra-low temperature liquid 12 may be liquid helium. Alternatively, the ultra-low temperature refrigerator 100 may also be a pulse tube refrigerator, a Stirling refrigerator, or other types of ultra-low temperature refrigerators.

[0063] In the above embodiment, the cryogenic device 10 is exemplified as a storage device for the cryogenic liquid 12, but other structures may also be used. For example, the cryogenic device 10 may also be a superconducting device, and the cryogenic refrigerator 100 may be used to cool the superconducting coils disposed inside the vacuum container 20.

[0064] The present invention has been described above based on the implementation method and using specific sentences, but the implementation method only illustrates one aspect of the principle and application of the present invention. Without departing from the scope of the idea of ​​the present invention specified in the technical solution, the implementation method allows for many variations or configuration changes.

[0065] Industrial Applicability

[0066] The present invention can be used in the field of ultra-low temperature refrigerators.

[0067] Explanation of symbols

[0068] 20 - vacuum container, 100 - ultra-low temperature refrigerator, 104 - cold head, 106 - cold head mounting seat, 106a - mounting flange, 106b - airtight bulkhead, 106c - driving source, 108 - flexible pipe, 110 - flexible pipe retainer.

Claims

1. A cryogenic refrigerator, characterized in that: have: A cold head, which can be mounted in a vacuum container; a cold head mounting seat configured to connect the cold head to the vacuum container in a manner allowing the cold head to move relative to the vacuum container; a flexible pipe connected to the cold head outside the vacuum container; and The flexible tube holder is configured to fix and hold the flexible tube relative to the vacuum container.

2. The ultra-low temperature refrigerator according to claim 1, characterized in that: The flexible tube holder holds the flexible tube at an end portion of the flexible tube on the cold head side.

3. The ultra-low temperature refrigerator according to claim 1 or 2, characterized in that: The flexible pipe includes a working gas pipe for supplying working gas to the cold head or discharging working gas from the cold head. The flexible conduit holder includes a working gas conduit holder that holds the working gas conduit.

4. The ultra-low temperature refrigerator according to claim 3, characterized in that: The working gas pipeline holder includes an intermediate joint having an internal flow path through which the working gas can flow. The working gas pipeline includes a first portion connecting the cold head to the intermediate joint and a second portion connected to the intermediate joint.

5. The ultra-low temperature refrigerator according to claim 3, characterized in that: The cold head mounting seat comprises: a mounting flange that can be mounted on the vacuum container; and a retractable airtight partition that connects the cold head to the mounting flange. The working gas pipeline retainer is fixed on the mounting flange.

6. The ultra-low temperature refrigerator according to claim 1 or 2, characterized in that: The flexible pipe includes a power supply cable for supplying power to the cold head. The flexible tube holder includes a cable holder that holds the power supply cable.

7. The ultra-low temperature refrigerator according to claim 6, characterized in that: The cold head mounting seat comprises: a mounting flange that can be mounted on the vacuum container; and a retractable airtight partition that connects the cold head to the mounting flange. The cable retainer is fixed to the mounting flange.

8. The ultra-low temperature refrigerator according to any one of claims 1 to 7, characterized in that: Also available: a driving source configured to be mounted on the cold head mounting seat and to move the cold head relative to the vacuum container; another flexible pipe connected to the driving source; and The other flexible conduit holder is configured to fix and hold the other flexible conduit relative to the vacuum container.

9. The ultra-low temperature refrigerator according to claim 8, characterized in that: The cold head mounting seat comprises: a mounting flange that can be mounted on the vacuum container; and a retractable airtight partition that connects the cold head to the mounting flange. The other flexible pipe retainer is fixed to the mounting flange.

Images