JP2022124111A - Cryogenic refrigerator and thermal switch for cryogenic device - Google Patents

Abstract

To shorten initial cooling time of a cryogenic device.SOLUTION: A cryogenic refrigerator 20 comprises a first cooling stage 22a, a second cooling stage 22b cooled to a lower temperature than that of the first cooling stage 22a, a first heat transfer terminal part 51 thermally connected to the first cooling stage 22a, a second heat transfer terminal part 52 thermally connected to the second cooling stage 22b, and a movable heat transfer element 54 movable between a connection position and a release position, and in which thermal connection between the first heat transfer terminal part 51 and the second heat transfer terminal part 52 is mediated when it is located at the connection position, and thermal connection with each of the first heat transfer terminal part 51 and the second heat transfer terminal part 52 is released when it is located at the release position.SELECTED DRAWING: Figure 1

Description

The present invention relates to cryogenic refrigerators and thermal switches for cryogenic devices.

It is conventionally known to provide a thermal switch in the heat transfer path from the cryogenic refrigerator to the superconducting coil. A pressurizing device for activating the thermal switch is provided outside the vacuum vessel containing the superconducting coil and extends through the vacuum vessel to the contacts of the thermal switch. Pressurization from the pressurizing device closes the thermal switch, which thermally couples the cryogenic refrigerator with the superconducting coil. Releasing the pressurizing device opens the thermal switch and breaks the thermal connection between the cryogenic refrigerator and the superconducting coil.

JP 2012-209381 A

In general, in the above-described cryogenic apparatus that cools an object to be cooled such as a superconducting coil using a cryogenic refrigerator, initial cooling is performed to cool the object to be cooled from room temperature to a target cooling temperature at the time of startup. . Use of the object to be cooled becomes possible after the initial cooling is completed. Therefore, it is desired that the time required for initial cooling be as short as possible.

One exemplary objective of certain aspects of the invention is to reduce the initial cooling time of cryogenic equipment.

According to one aspect of the invention, a cryogenic refrigerator includes a first cooling stage, a second cooling stage cooled to a lower temperature than the first cooling stage, and a first cooling stage thermally coupled to the first cooling stage. A heat transfer terminal portion, a second heat transfer terminal portion thermally coupled to the second cooling stage, and a coupling position and a release position are movable, and when in the coupling position, the first heat transfer terminal portion and the second heat transfer terminal portion are movable. 2 a movable heat transfer element that mediates thermal coupling of the heat transfer terminal portions and releases the thermal coupling between the first heat transfer terminal portion and the second heat transfer terminal portion when in the release position; Prepare.

According to one aspect of the invention, a cryogenic refrigerator includes a first cooling stage, a second cooling stage cooled to a lower temperature than the first cooling stage, and a moving transmission stage thermally coupled to the first cooling stage. A thermal element and a heat transfer terminal thermally coupled to the second cooling stage. the movable heat transfer element is movable between a coupling position and a standby position, has a side surface extending along the direction of movement thereof, and is thermally coupled to the heat transfer terminal portion at the side surface when in the coupling position; At the standby position, the thermal connection with the heat transfer terminal portion is released.

According to one aspect of the invention, a thermal switch for a cryogenic device comprises a first heat transfer terminal positionable on one of the cooling side or the cooled side of the cryogenic device; a second heat transfer terminal portion that can be installed on the other side, and a second heat transfer terminal portion that can be moved between a coupling position and a release position, and thermally couples the first heat transfer terminal portion and the second heat transfer terminal portion when in the coupling position. and a movable heat transfer element through which thermal coupling between the first heat transfer terminal portion and the second heat transfer terminal portion is released when in the release position.

According to one aspect of the invention, a thermal switch for a cryogenic device comprises a first heat transfer terminal positionable on one of the cooling side or the cooled side of the cryogenic device; a second heat transfer terminal portion that can be installed on the other side of the heat transfer terminal portion; a movable element that couples and releases the thermal coupling between the first heat transfer terminal portion and the second heat transfer terminal portion when in the released position.

ADVANTAGE OF THE INVENTION According to this invention, the initial cooling time of a cryogenic apparatus can be shortened.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the cryogenic apparatus which concerns on embodiment. 1 is a perspective view schematically showing a thermal switch according to an embodiment; FIG. 1 is a partially cutaway perspective view schematically showing a thermal switch according to an embodiment; FIG. 4 schematically shows an off state of the thermal switch according to the embodiment; 4 schematically shows an ON state of the thermal switch according to the embodiment; 4 is a perspective view schematically showing a movable heat transfer element of the thermal switch according to the embodiment; FIG. FIG. 4 is a partial cross-sectional view schematically showing part of a vertical cross section of a movable heat transfer element and an operation portion of the thermal switch according to the embodiment; It is a perspective view which shows an example of a heat-transfer terminal. It is a perspective view which shows an example of a terminal support member. FIG. 4 is a schematic diagram showing a thermal switch according to a comparative example; 4 schematically shows a standby state of the thermal switch according to the embodiment; 12(a) and 12(b) are diagrams schematically showing a thermal switch according to another embodiment. 13(a) and 13(b) are diagrams schematically showing a thermal switch according to still another embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, 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 denoted by the same reference numerals, and overlapping descriptions are omitted as appropriate. The scales and shapes of the illustrated parts are set for convenience in order to facilitate explanation, and should not be construed as limiting unless otherwise specified. The embodiment is an example and does not limit the scope of the present invention. All features and combinations thereof described in the embodiments are not necessarily essential to the invention.

FIG. 1 is a diagram schematically showing a cryogenic apparatus according to an embodiment. FIG. 2 is a perspective view schematically showing the thermal switch according to the embodiment, and FIG. 3 is a partially cutaway perspective view thereof. FIG. 3 shows a longitudinal section of the thermal switch shown in FIG. FIG. 4 schematically shows the OFF state of the thermal switch according to the embodiment, and FIG. 5 schematically shows the ON state of the thermal switch according to the embodiment.

The cryogenic apparatus 10 includes an object 12 to be cooled, a cryogenic refrigerator 20 that cools the object 12 to be cooled, and a vacuum vessel 30 in which the object 12 to be cooled is housed and in which the cryogenic refrigerator 20 is installed.

In this embodiment, the cryogenic device 10 is a superconducting magnet device and the object to be cooled 12 is a superconducting coil. A superconducting magnet device is used as a magnetic field source for, for example, a single crystal pulling device, an NMR system, an MRI system, an accelerator such as a cyclotron, a high energy physical system such as a nuclear fusion system, or other high magnetic field utilization equipment (not shown). It is installed in a magnetic field utilization device and can generate a high magnetic field required for the device. The cryogenic device 10 may be various devices that utilize a cryogenic environment, and the object to be cooled 12 may be various devices such as sensors that are used in the cryogenic environment, and furthermore, a device that cools such devices such as It may also be a cryogenic refrigerant such as helium.

The cryogenic refrigerator 20 includes a refrigerant gas (for example, helium gas) compressor (not shown) and an expander also called a cold head. The compressor and the expander constitute a refrigeration cycle of the cryogenic refrigerator 20. , thereby providing cryogenic cooling. Cryogenic refrigerator 20 is, by way of example, a two-stage Gifford-McMahon (GM) refrigerator. The cryogenic refrigerator 20 includes a first cooling stage 22a and a second cooling stage 22b as low-temperature portions that are cooled to cryogenic temperatures. These cooling stages are arranged in a vacuum vessel 30 . The first cooling stage 22a and the second cooling stage 22b are made of, for example, metallic materials such as copper or other materials with high thermal conductivity. During operation of the cryogenic refrigerator 20, the first cooling stage 22a is cooled to a first cooling temperature, such as 30K-80K, and the second cooling stage 22b is cooled to a second cooling temperature, such as 3K, which is lower than the first cooling temperature. Cooled to ~20K.

The cryogenic refrigerator 20 also includes a first cylinder 24 a , a second cylinder 24 b , and a drive section 26 . A first cylinder 24a connects the drive 26 to the first cooling stage 22a, and a second cylinder 24b connects the first cooling stage 22a to the second cooling stage 22b. The first cooling stage 22a, the second cooling stage 22b, the first cylinder 24a, and the second cylinder 24b are inserted into the vacuum vessel 30 through the opening of the vacuum vessel 30, and the driving section 26 is attached to the opening. A cryogenic refrigerator 20 is installed in a vacuum vessel 30 . In the illustrated example, the cryogenic refrigerator 20 is installed vertically in the vacuum vessel 30 with the drive section 26 facing upward and the low temperature section facing downward, but other orientations are also possible. is.

The first cylinder 24a and the second cylinder 24b are, for example, cylindrical members, and the second cylinder 24b has a smaller diameter than the first cylinder 24a. The first cylinder 24a and the second cylinder 24b are arranged coaxially, and the lower end of the first cylinder 24a is rigidly connected to the upper end of the second cylinder 24b. When the cryogenic refrigerator 20 is a GM refrigerator, the first cylinder 24a and the second cylinder 24b accommodate a first displacer and a second displacer containing a cold storage material, respectively. The first displacer and the second displacer are connected to each other and reciprocable along the first cylinder 24a and the second cylinder 24b, respectively.

The drive unit 26 includes a motor and a coupling mechanism that couples the motor to the first displacer and the second displacer so as to convert the rotational motion output by the motor into reciprocating motion of the displacer. The drive unit 26 also includes a pressure switching valve that periodically switches the pressure inside the first cylinder 24a and the second cylinder 24b between high and low pressures, and this pressure switching valve is also driven by the same motor.

In addition, although one cryogenic refrigerator 20 is shown as an example in FIG. A plurality of cryogenic refrigerators 20 may be provided to cool the . Cryogenic refrigerator 20 may also be a pulse tube refrigerator, a Stirling refrigerator, or some other type of cryogenic refrigerator.

Vacuum vessel 30 is configured to separate vacuum region 32 from external environment 14 . Vacuum vessel 30 may be, for example, a cryostat. A vacuum region 32 is defined within the vacuum vessel 30 and the external environment 14 may be an atmospheric region. The object to be cooled 12 and the cryogenic portion of the cryogenic refrigerator 20 are located in a vacuum region 32 and are vacuum insulated from the external environment 14 . Insulating material may be provided along the surfaces of, or within the wall members of the vacuum vessel 30 that separate the vacuum region 32 from the external environment 14 to enhance thermal insulation.

A radiant heat shield 40 is disposed in the vacuum region 32 along with the cold section of the cryogenic refrigerator 20 and the object 12 to be cooled. The radiation heat shield 40 is thermally coupled with the first cooling stage 22a and cooled to the first cooling temperature. The radiation heat shield 40 is directly attached to the first cooling stage 22a and is thermally coupled with the first cooling stage 22a. Alternatively, the radiation heat shield 40 may be attached to the first cooling stage 22a via a flexible or rigid heat transfer member. The radiant heat shield 40 is made of a metallic material such as copper or other material with high thermal conductivity. The radiation heat shield 40 is arranged so as to surround the object 12 to be cooled to the second cooling temperature, the second cooling stage 22b of the cryogenic refrigerator 20, and other low temperature parts, and protects these low temperature parts from external radiant heat. can be thermally protected.

The object 12 to be cooled is thermally coupled to the second cooling stage 22b via the heat transfer member 42 and cooled to the second cooling temperature. Heat transfer member 42 may be a flexible or rigid heat transfer member and is formed of a metallic material such as copper or other material with high thermal conductivity, for example. The object 12 to be cooled may be directly attached to the second cooling stage 22b.

Cryogenic refrigerator 20 includes a thermal switch 50 . The thermal switch 50 includes a first heat transfer terminal portion 51 thermally coupled to the first cooling stage 22a and a second heat transfer terminal portion 52 thermally coupled to the second cooling stage 22b. The first heat transfer terminal portion 51 is attached to the radiation heat shield 40 and is thermally coupled to the first cooling stage 22 a through the radiation heat shield 40 . The second heat transfer terminal portion 52 is attached to the heat transfer member 42 and is thermally coupled to the second cooling stage 22b via the heat transfer member 42 . The first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 are spaced apart and are not in contact with each other.

The first heat transfer terminal portion 51 may be attached to a heat transfer member different from the radiation heat shield 40, and may be thermally coupled to the first cooling stage 22a via this heat transfer member. The second heat transfer terminal portion 52 may be attached to a heat transfer member different from the heat transfer member 42, and may be thermally coupled to the second cooling stage 22b via this heat transfer member.

Thermal switch 50 also includes a movable heat transfer element 54 and an operating portion 56 . The movable heat transfer element 54 is movable between a coupled position and a released position, mediates thermal coupling between the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 when in the coupled position, and moves to the released position. , the thermal coupling between the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 is released. That is, thermal switch 50 is turned on when movable heat transfer element 54 is in the coupled position, and thermal switch 50 is turned off when movable heat transfer element 54 is in the released position. The operation unit 56 enables the thermal switch 50 to be turned on and off from outside the vacuum vessel 30 . Operation of the operating portion 56 moves the movable heat transfer element 54 from the unlocked position to the coupled position or from the coupled position to the unlocked position to turn the thermal switch 50 on and off. In FIG. 1, the moveable heat transfer element 54 is shown in solid lines in the disengaged position, and for clarity the moveable heat transfer element 54 in the coupled position is shown in dashed lines.

FIG. 6 is a perspective view schematically showing the movable heat transfer element 54 of the thermal switch 50 according to the embodiment. FIG. 7 is a partial cross-sectional view schematically showing part of the longitudinal cross-section of the movable heat transfer element 54 and the operating portion 56 of the thermal switch 50 according to the embodiment.

2, 6 and 7, the moveable heat transfer element 54 has a hollow cylindrical shape and is made of a metallic material such as copper or other material with high thermal conductivity. The direction of the central axis of the movable heat transfer element 54 corresponds to the movement direction of the movable heat transfer element 54 . The moveable heat transfer element 54 has a side surface 54a extending along its direction of movement. The side surface 54 a corresponds to the cylindrical outer peripheral surface of the movable heat transfer element 54 . As will be described later, when the movable heat transfer element 54 is in the coupled position, the side surface 54a is in contact with each of the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52, whereby the movable heat transfer element 54 is , mediate the thermal coupling between the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 . A thread groove 54 b is formed on the inner peripheral surface of the movable heat transfer element 54 . Also, as shown, the movable heat transfer element 54 has a slit 54c extending axially along its length in the side surface 54a.

A tapered surface 54 d may be formed at the tip of the movable heat transfer element 54 to facilitate insertion of the movable heat transfer element 54 into the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 .

In this embodiment, the manipulator 56 is rotatable about the central axis of the movable heat transfer element 54, and the movable heat transfer element 54 is manipulated to move along the central axis when the manipulator 56 is rotated. It is connected with the part 56 .

The operating portion 56 has a rotating shaft 56a. The rotating shaft 56a is supported by the vacuum vessel 30 so as to be rotatable about its axis. The rotating shaft 56a may be made of a metal material such as stainless steel, or may be made of a heat insulating material such as a synthetic resin material. The rotating shaft 56a is provided through the wall of the vacuum vessel 30 from the outside to the inside of the vacuum vessel 30, and can be rotated by operating the rotating shaft 56a from outside the vacuum vessel 30. As shown in FIG.

A rotary shaft seal 56b is provided at a portion of the vacuum vessel 30 through which the rotary shaft 56a penetrates in order to maintain airtightness. The rotary shaft seal 56b may be, for example, a general-purpose sealing member such as a Wilson seal. By using the rotating shaft seal 56b, it is possible to eliminate a structure that greatly protrudes outside the vacuum vessel 30. FIG.

A threaded portion 56c that engages with the threaded groove 54b of the movable heat transfer element 54 is provided at the tip of the rotating shaft 56a within the vacuum vessel 30 . When the rotary shaft 56a rotates around the axis, the threaded portion 56c rotates around the axis together with the rotary shaft 56a. The screw groove 54b and the threaded portion 56c are provided as a motion converting portion that converts the rotation of the rotating shaft 56a into axial linear movement of the movable heat transfer element 54. As shown in FIG.

Further, the operation portion 56 has a rotation restricting member 56d. The rotation restricting member 56 d extends close to and parallel to the rotating shaft 56 a and has its tip end inserted into the slit 54 c of the movable heat transfer element 54 . The rotation restricting member 56d may be made of a metal material such as stainless steel, or may be made of a heat insulating material such as a synthetic resin material. The movable heat transfer element 54 can move between the coupled position and the released position while the tip of the rotation restricting member 56d is inserted into the slit 54c. The tip of the rotation restricting member 56d inserted into the slit 54c is not connected to the rotating shaft 56a. The opposite end of the rotation restricting member 56d is fixed to the vacuum vessel 30 in the vicinity of the rotating shaft seal 56b.

Therefore, the rotation restricting member 56d allows the axial movement of the movable heat transfer element 54 while restricting the rotating shaft 56a and the movable heat transfer element 54 from rotating together. When the rotating shaft 56a rotates about its axis, the movable heat transfer element 54 can move axially along the rotation restricting member 56d due to the engagement between the thread groove 54b and the threaded portion 56c.

In addition, the movable heat transfer element 54 may be provided with a fall prevention structure 54e. As illustrated, the rotating shaft 56a may have a smaller diameter than the threaded portion 56c, and the end portion of the movable heat transfer element 54 may be formed with a radially inward projection. The engagement between the convex portion and the threaded portion 56 c can prevent the movable heat transfer element 54 from falling off from the operation portion 56 .

Referring to FIGS. 1 to 5 again, the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 each have a shape into which the movable heat transfer element 54 can be inserted. When in position, it is inserted into the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 and thermally coupled with these heat transfer terminal portions. Since the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 have substantially the same structure, the first heat transfer terminal portion 51 will be described below as a representative.

The first heat transfer terminal portion 51 has a heat transfer terminal 60 . The heat transfer terminals 60 are in contact with the side surfaces 54a of the movable heat transfer element 54 when the movable heat transfer element 54 is in the coupled position and are out of contact with the side surfaces 54a of the movable heat transfer element 54 when the movable heat transfer element 54 is in the released position. come into contact.

The heat transfer terminal 60 has a hollow cylindrical shape and is made of a metal material such as copper or other materials with high thermal conductivity. A heat transfer terminal 60 is arranged coaxially with the movable heat transfer element 54 . The inner peripheral surface of the heat transfer terminal 60 defines an insertion opening 60a into which the movable heat transfer element 54 is inserted. The inner peripheral surface of the heat transfer terminal 60 may have a tapered surface at the entrance of the insertion opening 60a to facilitate reception of the movable heat transfer element 54 to be inserted. When the movable heat transfer element 54 is inserted into the insertion opening 60a of the heat transfer terminal 60 and is in the coupling position, the side surface 54a of the movable heat transfer element 54 is in surface contact with the inner peripheral surface of the heat transfer terminal 60, and the movable heat transfer element 54 is thermally coupled with the heat transfer terminal 60 .

FIG. 8 is a perspective view showing an example of the heat transfer terminal 60. FIG. The heat transfer terminal 60 may be formed by cylindrically arranging a plurality of members obtained by dividing a single cylindrical member in the circumferential direction. For example, as illustrated, the heat transfer terminal 60 may be formed by arranging eight members in a cylindrical shape. Alternatively, the heat transfer terminal 60 may have two semi-cylindrical members.

The first heat transfer terminal portion 51 also includes a terminal support member 62 that supports the heat transfer terminal 60 . The terminal support member 62 has a hollow cylindrical shape and is made of a metal material such as stainless steel. The terminal support member 62 is positioned coaxially with the heat transfer terminals 60 (ie, coaxially with the moveable heat transfer element 54). The terminal support member 62 has a larger diameter than the heat transfer terminal 60 and is arranged inside the terminal support member 62 . In the case of the first heat transfer terminal portion 51, the terminal support member 62 includes, at its end (e.g., the end opposite to the entrance side into which the movable heat transfer element 54 is inserted) a heat transfer material such as a radiant heat shield 40, for example. It is fixed to the thermal element. In the case of the second heat transfer terminal portion 52 , the terminal support member 62 is fixed to the heat transfer member 42 .

The heat transfer terminals 60 are elastically supported by the terminal support members 62 so as to be radially displaceable with respect to the terminal support members 62 while their axial and circumferential displacements are restrained. Specifically, the heat transfer terminal 60 is elastically supported by the terminal support member 62 by a plurality of elastic members 64 . There is a radial gap between the outer peripheral surface of the heat transfer terminal 60 and the inner peripheral surface of the terminal support member 62, and the elastic member 64 is arranged in this radial gap. Each elastic member 64 connects the outer peripheral surface of the heat transfer terminal 60 and the inner peripheral surface of the terminal support member 62 and elastically biases the heat transfer terminal 60 against the terminal support member 62 in the radial direction. The elastic member 64 may be, for example, a spring member such as a coil spring, or other elastic member.

Further, restraining portions are provided for restraining displacement of the heat transfer terminals 60 in the axial direction and the circumferential direction with respect to the terminal supporting member 62 . As an example, this restraint has a plurality of support pins 66 . The plurality of support pins 66 may be arranged at regular intervals in the axial and circumferential directions. An elastic member 64 may be provided for each support pin 66 .

FIG. 9 is a perspective view showing an example of the terminal support member 62. As shown in FIG. The terminal support member 62 is provided with a plurality of pin holes 62a penetrating the terminal support member 62 in the radial direction. Each support pin 66 is inserted through the corresponding pin hole 62a, and the tip of the support pin 66 is fixed to the heat transfer terminal 60 as shown in FIGS. For example, the tip of the support pin 66 may be a screw, a screw hole 60b corresponding to the outer peripheral surface of the heat transfer terminal 60 is formed (see FIG. 8), and the support pin 66 is screwed to the heat transfer terminal 60. good too.

Therefore, the heat transfer terminal 60 can be radially displaced along the support pin 66 with respect to the terminal support member 62 while being elastically supported by the terminal support member 62 via the elastic member 64 . At this time, the support pin 66 restricts axial and circumferential displacement of the heat transfer terminal 60 with respect to the terminal support member 62 .

The heat transfer terminal 60 is connected and thermally coupled with the heat transfer member via the flexible heat transfer member 68 . The flexible heat transfer member 68 may be formed as a flexible bundle of wires or a laminate of foils, for example, and may be formed of a highly thermally conductive material such as copper. In the case of the first heat transfer terminal portion 51 , the heat transfer terminal 60 may be connected to the radiation heat shield 40 via the flexible heat transfer member 68 . In the case of the second heat transfer terminal portion 52 , the heat transfer terminal 60 may be connected to the heat transfer member 42 via the flexible heat transfer member 68 .

A flexible heat transfer member 68 may be connected to the end of the heat transfer terminal 60 as shown. In order to avoid interference with the flexible heat transfer member 68, the terminal support member 62 may be provided with a notch 62b for passing the flexible heat transfer member 68 (see FIG. 9).

Next, the on/off switching operation of the thermal switch 50 will be described with reference to FIGS. 4 and 5. FIG. First, as shown in FIG. 4 , when the thermal switch 50 is off, the movable heat transfer element 54 is in the release position and away from the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 . The movable heat transfer element 54 is arranged between the first heat transfer terminal portion 51 and the vacuum vessel 30 and held by the operation portion 56 (see FIG. 1). The heat transfer terminal 60 of each of the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 is at a position pushed radially inward by the elastic member 64 . At this time, the diameter D1 of the insertion opening 60 a of the heat transfer terminal 60 is slightly smaller than the outer diameter D2 of the movable heat transfer element 54 .

A worker operates the operation unit 56 from outside the vacuum vessel 30 . The operator rotates the rotating shaft 56a around the axis manually or using an appropriate electric device. When the rotating shaft 56a rotates about its axis, the movable heat transfer element 54 moves axially along the rotation restricting member 56d due to the engagement between the thread groove 54b and the threaded portion 56c (see FIG. 7). ), toward the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 . The movable heat transfer element 54 is first inserted into the insertion opening 60a of the heat transfer terminal 60 of the first heat transfer terminal portion 51, and then moved in the axial direction until the heat transfer terminal 60 of the second heat transfer terminal portion 52 is inserted. It is inserted into mouth 60a. In this way, the moveable heat transfer element 54 is moved from the unlocked position to the coupled position and the thermal switch 50 is switched from off to on.

As shown in FIG. 5 , when the thermal switch 50 is on, the side surface 54 a of the movable heat transfer element 54 is in surface contact with the inner peripheral surface of the heat transfer terminal 60 of the first heat transfer terminal portion 51 . At this time, the movable heat transfer element 54 pushes the heat transfer terminal 60 radially outward toward the terminal support member 62 and compresses the elastic member 64 . Therefore, the heat transfer terminal 60 is elastically pressed against the side surface 54a of the movable heat transfer element 54 when the movable heat transfer element 54 is in the coupled position.

Thus, the movable heat transfer element 54 is thermally coupled to the first cooling stage 22a via the heat transfer terminals 60, the flexible heat transfer member 68, and the radiant heat shield 40. FIG. Similarly, the movable heat transfer element 54 is thermally coupled to the second cooling stage 22b via the heat transfer terminal 60 of the second heat transfer terminal portion 52, the flexible heat transfer member 68, and the heat transfer member 42. It will be. In this manner, the movable heat transfer element 54 mediates the thermal coupling between the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 when in the coupled position. Thermal switch 50 thereby thermally couples first cooling stage 22a and second cooling stage 22b.

Conversely, by rotating the rotating shaft 56a in the opposite direction around the axis, the movable heat transfer element 54 is pulled out from the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52, and the first heat transfer terminal portion 51 is pulled out. and away from the second heat transfer terminal portion 52 . In this way, the moveable heat transfer element 54 is moved from the coupled position to the released position and the thermal switch 50 is switched from on to off. The thermal coupling between the first cooling stage 22a and the second cooling stage 22b is released.

The thermal switch 50 may also be provided with a shutter 70, as shown in FIGS. The shutter 70 is provided between the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52, is opened when the movable heat transfer element 54 is in the coupling position, and is opened when the movable heat transfer element 54 is in the release position. close up. The shutter 70 may be connected to the radiation heat shield 40 or the first heat transfer terminal portion 51 via a spring or an elastic member (not shown) and biased by the elastic member so as to be closed. The shutter 70 may be opened by the moveable heat transfer element 54 pushing the shutter 70 apart and sliding outward when the moveable heat transfer element 54 hits the shutter 70 . In order to facilitate the outward sliding of the shutter 70 along with the axial movement of the movable heat transfer element 54, the tip of the shutter 70 may be provided with a tapered surface 70a against which the tip of the movable heat transfer element 54 abuts. good.

By providing the shutter 70, when the thermal switch 50 is turned off, radiant heat that may enter the second heat transfer terminal portion 52 from the movable heat transfer element 54 through the insertion opening 60a of the first heat transfer terminal portion 51 is shielded. can be done.

In the illustrated example, the shutter 70 is installed on the radiation heat shield 40 or the first heat transfer terminal portion 51 and arranged on the exit side of the insertion opening 60 a of the first heat transfer terminal portion 51 . Alternatively, the shutter 70 may be installed on the heat transfer member 42 or the second heat transfer terminal portion 52 and arranged on the inlet side of the insertion opening 60 a of the second heat transfer terminal portion 52 .

Thermally coupling first cooling stage 22a and second cooling stage 22b via thermal switch 50 is advantageous for initial cooling of cryogenic apparatus 10 upon start-up. In initial cooling, the cryogenic refrigerator 20 is cooled from ambient temperature (eg, room temperature) to a target cryogenic temperature. Generally, the refrigerating capacity in the first cooling stage 22a of the cryogenic refrigerator 20 is greater than the refrigerating capacity in the second cooling stage 22b. When the second cooling stage 22b is at a high temperature, such as ambient temperature, the time required for initial cooling can be reduced by utilizing the refrigerating capacity of the first cooling stage 22a to assist in cooling the second cooling stage 22b. .

After the second cooling stage 22b has been cooled to the first cooling temperature, the thermal switch 50 is switched from on to off by operating the operating portion 56 . The second cooling stage 22b is disconnected from the first cooling stage 22a and cooled to a second cooling temperature. Once the initial cooling of the cryogenic refrigerator 20 is completed in this way, the operation of the cryogenic apparatus 10 can be started.

Since the movable heat transfer element 54 is connected to an operating portion 56 having a portion exposed to the outside of the vacuum vessel 30, the heat input from the external environment 14 through the operating portion 56 causes heat to be generated during operation of the cryogenic apparatus 10. , the cooling stages of the cryogenic refrigerator 20 and the object to be cooled 12 can be hot. If the movable heat transfer element 54 is in contact with the first heat transfer terminal portion 51 (or the second heat transfer terminal portion 52), the first heat transfer terminal portion 51 is transferred from the movable heat transfer element 54 by heat conduction. (or the second heat transfer terminal portion 52), and furthermore, the cryogenic cooling of the object 12 to be cooled can be affected. However, when the movable heat transfer element 54 is in the released position, the movable heat transfer element 54 is disconnected from both the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 . Therefore, during operation of the cryogenic apparatus 10, heat input to the object to be cooled 12 due to heat conduction from the movable heat transfer element 54 can be suppressed.

FIG. 10 is a schematic diagram showing a thermal switch 80 according to a comparative example. This thermal switch 80 is composed of a heat transfer body 81 and a heat transfer plate 82 . The heat transfer body 81 is movable with respect to the heat transfer plate 82, and the heat transfer body 81 and the heat transfer plate 82 have surfaces facing each other. Heat transfer body 81 approaches heat transfer plate 82, the two surfaces momentarily contact, and thermal switch 80 is turned on. The interface between the heat transfer body 81 and the heat transfer plate 82 is perpendicular to the relative movement direction 83 of the heat transfer body 81 . The contact surface pressure acting between the heat transfer body 81 and the heat transfer plate 82 is generated by pressing the heat transfer body 81 against the heat transfer plate 82 , and the direction of this force coincides with the relative movement direction 83 .

In the configuration of the thermal switch 80 according to the comparative example, the contact surface pressure between the heat transfer body 81 and the heat transfer plate 82 and thus the thermal resistance are closely correlated with the pressing force. In other words, the thermal resistance between the heat transfer body 81 and the heat transfer plate 82 sensitively fluctuates due to slight changes in the pressing force. In order to precisely achieve the desired thermal resistance, it is necessary to precisely adjust the pressing force each time the thermal switch 80 is turned on. However, this is not always easy. In addition, in order to sufficiently reduce the thermal resistance, it is required to considerably increase the contact surface pressure, that is, the force that presses the heat transfer body 81 and the heat transfer plate 82 against each other. . In other words, the thermal switch 80 according to the comparative example lacks reproducibility of thermal resistance when the thermal switch is turned on, and there is a limit to the reduction in thermal resistance that can be achieved.

Therefore, in the thermal switch 80 according to the comparative example, the contact surface pressure is insufficient, the thermal resistance is increased, and a temperature difference is likely to occur between the heat transfer body 81 and the heat transfer plate 82 . As a result, the cooling temperature of the object to be cooled, such as the superconducting coil connected to the heat transfer plate 82, may not drop sufficiently to the temperature that the cryogenic refrigerator can achieve. In order to avoid poor cooling of the object to be cooled, it may be necessary to consider adopting a cryogenic refrigerator with a larger cooling capacity or installing an additional cryogenic refrigerator.

In contrast, according to the thermal switch 50 according to the embodiment, the movable heat transfer element 54 has the side surface 54a extending along the direction of movement thereof. Each of the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 is in contact with the side surface 54a of the movable heat transfer element 54 when the movable heat transfer element 54 is in the coupling position, and the movable heat transfer element 54 is in the release position. A heat transfer terminal 60 is provided that is out of contact with the side surface 54a of the movable heat transfer element 54 when the heat transfer element 54 is in contact.

By using the side surface 54 a of the movable heat transfer element 54 , a wider contact area between the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 is ensured compared to the comparative example, and the heat of the thermal switch 50 is increased. It becomes easier to reduce the resistance.

By installing a plurality of thermal switches 50 according to the embodiment, it is also possible to widen and secure the contact area.

Further, according to the thermal switch 50 according to the embodiment, the heat transfer terminal 60 is elastically pressed against the side surface 54a of the movable heat transfer element 54 when the movable heat transfer element 54 is in the coupling position. Since the contact surface pressure between the movable heat transfer element 54 and the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 can be determined by designing the elastic member 64, a desired magnitude of thermal resistance can be determined. easier to implement.

What should be noted here is that the contact surface pressure is generated in a direction different from the direction of relative movement, for example, in a direction substantially perpendicular to the direction. Therefore, the contact surface pressure and thermal resistance are independent or hardly dependent on the magnitude of the force causing the relative movement. As long as the movable heat transfer element 54 can be inserted and removed, the force in the moving direction may be small. Therefore, the operation unit 56 can employ a simple configuration.

The contact surface pressure acting between the movable heat transfer element 54 and the heat transfer terminal 60, that is, the thermal resistance, mainly depends on the design of these heat transfer parts, such as the shape, size, and material of the movable heat transfer element 54 and the heat transfer terminal 60. can be determined. As with the thermal switch 80 of the comparative example, dynamic factors such as push force have little or no role in determining thermal resistance. Therefore, by using the thermal switch 50 according to the embodiment, the thermal resistance can be easily managed and the reproducibility can be improved.

Thermal switch 50 can also accommodate thermal contraction due to cooling. When the first heat-transfer terminal portion 51 and the second heat-transfer terminal portion 52 are cooled, there is a concern that the center axis of each of them may be displaced with respect to the movable heat-transfer element 54 due to thermal contraction. However, since the heat transfer terminal 60 is elastically supported, when the movable heat transfer element 54 is inserted into the heat transfer terminal 60, even if there is axial misalignment, it can be elastically absorbed. . The thermal switch 50 can self-adjust for misalignment between the movable heat transfer element 54 and the heat transfer terminals due to thermal contraction or assembly accuracy.

Further, in the thermal switch 50 according to the embodiment, the operating portion 56 is rotatable about the rotation axis 56a, and the movable heat transfer element 54 is arranged to move along the rotation axis 56a when the operating portion 56 is rotated. is connected to the operation unit 56 at the . Therefore, the first stage and the second stage of the cryogenic refrigerator 20 can be thermally detached by a simple operation.

By the way, if the cryogenic device 10 is a superconducting magnet device, countermeasures against loss of superconductivity, also called quenching, are important. When a quench occurs, a rapid temperature rise can occur in the superconducting coil. In some cases, the superconducting coil can be heated from the second cooling temperature of approximately 4K to a temperature above the first cooling temperature of the radiant heat shield 40 (eg, 50K) in a very short time.

The cryogenic device 10 and thermal switch 50 according to the embodiments can also be used to quickly return to the original cooling state from an increase in temperature due to an unforeseen event such as a quench. That is, by moving the movable heat transfer element 54 from the released position to the coupled position, the first cooling stage 22a and the second cooling stage 22b are thermally coupled via the thermal switch 50, thereby cooling the first cooling stage 22a. The capacity can be used to re-cool the second cooling stage 22b and the object 12 to be cooled.

Also, in order to re-cool the second cooling stage 22b and the object to be cooled 12 in a shorter time, the movable heat transfer element 54 is pre-thermally coupled to the first cooling stage 22a and maintained at the first cooling temperature. may be Alternatively, the movable heat transfer element 54 may be permanently thermally coupled with the first cooling stage 22a and maintained at the first cooling temperature. Such an embodiment is described below with reference to FIGS. 11, 12(a) and 12(b).

In addition to the coupled and uncoupled positions, the moveable heat transfer element 54 may also be movable into a "parking position." The standby position corresponds to an intermediate position between the coupling position and the release position.

As shown in FIG. 11, when the movable heat transfer element 54 is in the standby position, the side surface 54a of the movable heat transfer element 54 is thermally coupled to the first heat transfer terminal portion 51, and the second heat transfer terminal portion The thermal coupling with 52 is released. Further, as described above, the movable heat transfer element 54 is thermally connected to the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 at the side surface 54a of the movable heat transfer element 54 when it is in the connection position. (See FIG. 5), when it is in the release position, it is separated from both the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 (see FIG. 4).

By operating the operating portion 56, the movable heat transfer element 54 is moved from the standby position to the coupling position or from the coupling position to the standby position. Similarly, by operating the operating portion 56, the movable heat transfer element 54 is moved from the standby position to the release position or from the release position to the standby position.

During operation of the cryogenic apparatus 10 (ie, after initial cooling is completed), the moveable heat transfer element 54 waits in the standby position. Thereafter, if an unforeseen event such as a quench occurs and the heat transfer member 42 is heated, the movable heat transfer element 54 is moved from the standby position to the coupled position, and the radiant heat shield 40 and the heat transfer member 42 are thermally switched. 50 are thermally coupled. In this case, unlike the case where the movable heat transfer element 54 is at the release position, the movable heat transfer element 54 has already been cooled to the first cooling temperature at the standby position, so the movable heat transfer element 54 is cooled from normal temperature to the first cooling temperature. The time required for cooling to the cooling temperature is eliminated. Therefore, cooling of the second cooling stage 22b and the object to be cooled 12 can be started quickly by the first cooling stage 22a via the thermal switch 50. FIG.

After the second cooling stage 22b and the object to be cooled 12 are recooled to the first cooling temperature, the movable heat transfer element 54 is again returned to the standby position shown in FIG. Alternatively, the moveable heat transfer element 54 may be moved to the unlocked position shown in FIG. The second cooling stage 22b is disconnected from the first cooling stage 22a and recooled to the second cooling temperature. When the re-cooling of the second cooling stage 22b and the object to be cooled 12 is completed in this manner, the operation of the cryogenic apparatus 10 can be resumed.

12(a) and 12(b) are diagrams schematically showing a thermal switch 50 according to another embodiment. Figure 12(a) shows the thermal switch 50 in the standby position and Figure 12(b) shows the thermal switch 50 in the coupled position.

Thermal switch 50 includes a moveable heat transfer element 54 thermally coupled to first cooling stage 22a and a second heat transfer terminal portion 52 thermally coupled to second cooling stage 22b. In this embodiment, the first heat transfer terminal portion 51 is not provided, and only the second heat transfer terminal portion 52 is provided.

As with the previous embodiments, the moveable heat transfer element 54 has side surfaces 54a extending along its direction of movement. Movable heat transfer element 54 is connected via flexible heat transfer member 68 to radiant heat shield 40 or other portion that is thermally coupled to first cooling stage 22a. Movable heat transfer element 54 may be connected to first cooling stage 22 a via flexible heat transfer member 68 . Thus, the movable heat transfer element 54 is constantly thermally coupled with the first cooling stage 22a and maintained at the first cooling temperature.

The movable heat transfer element 54 is movable between a coupling position and a standby position, and is thermally coupled to the second heat transfer terminal portion 52 at the side surface 54a of the movable heat transfer element 54 at the coupling position, and moves to the standby position. At some point, the thermal coupling with the second heat transfer terminal portion 52 is released. The thermal switch 50 includes an operating portion 56, and operation of the operating portion 56 moves the movable heat transfer element 54 from the standby position to the coupling position or from the coupling position to the standby position, turning the thermal switch 50 on and off. be done.

The thermal switch 50 may be provided with a shutter 70 . The shutter 70 is provided between the second heat transfer terminal portion 52 and the movable heat transfer element 54 at the standby position. Shutter 70 is open when moveable heat transfer element 54 is in the coupled position and closed when moveable heat transfer element 54 is in the standby position.

According to the embodiment shown in FIGS. 12(a) and 12(b), similar to the embodiments described above, during initial cooling, the movable heat transfer element 54 is moved to the coupled position and the first stage of cooling is performed. 22 a and second cooling stage 22 b may be thermally coupled via thermal switch 50 . Therefore, the time required for initial cooling can be shortened by using the refrigerating capacity of the first cooling stage 22a to assist the cooling of the second cooling stage 22b.

Even when the temperature of the heat transfer member 42 rises due to the occurrence of quench, the movable heat transfer element 54 is moved from the standby position to the coupling position, and the first cooling stage 22a and the second cooling stage 22b are connected via the thermal switch 50. thermally coupled. Since the movable heat transfer element 54 is cooled to the first cooling temperature in the standby position, the first cooling stage 22a can immediately begin cooling the second cooling stage 22b and the object to be cooled 12 via the thermal switch 50. can. After the second cooling stage 22b and the object to be cooled 12 are recooled to the first cooling temperature, the movable heat transfer element 54 is returned to the standby position again. The second cooling stage 22b is disconnected from the first cooling stage 22a and recooled to the second cooling temperature.

13(a) and 13(b) are diagrams schematically showing a thermal switch 50 according to still another embodiment. Figure 13(a) shows the thermal switch 50 in the disengaged position and Figure 13(b) shows the thermal switch 50 in the coupled position.

The first heat transfer terminal portion 51 is coaxially arranged radially inside the second heat transfer terminal portion 52 . When the thermal switch 50 is at the release position, the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 are radially separated from each other. The second heat transfer terminal portions 52 are in contact with each other.

Thermal switch 50 includes a moveable element 154 instead of moveable heat transfer element 54 . Movable element 154 may have the same shape and structure as movable heat transfer element 54 . Thus, operation of the operating portion 56 moves the movable element 154 from the unlocked position to the coupled position or from the coupled position to the unlocked position to turn the thermal switch 50 on and off. The operating portion 56 is rotatable about the central axis of the movable element 154, and the movable heat transfer element 54 is coupled with the operating portion 56 so as to move along the central axis when the operating portion 56 is rotated. While the moveable heat transfer element 54 is made of a highly thermally conductive material such as copper, the moveable element 154 need not be responsible for heat transfer as described below and may be made of a heat insulating material or other suitable material. good.

The first heat transfer terminal portion 51 includes a heat transfer terminal 60 having a shape into which the movable element 154 can be inserted, and a terminal support member 62 that supports the heat transfer terminal 60 . The heat transfer terminal 60 is connected to the radiant heat shield 40 by a flexible heat transfer member 68 , and the terminal support member 62 is fixed to the radiant heat shield 40 . An elastic member 64 is interposed between the heat transfer terminal 60 and the terminal support member 62 so that the heat transfer terminal 60 can elastically move radially with respect to the terminal support member 62 . The elastic member 64 is for reliably turning off the thermal switch 50, and may be a light load spring. The elastic member 64 also helps absorb displacement of the first heat transfer terminal portion 51 due to thermal contraction of the radiation heat shield 40 . The terminal support member 62 may be pipe-shaped.

The second heat transfer terminal portion 52 is similar to the above-described embodiment, and includes heat transfer terminals 60 , terminal support members 62 , elastic members 64 , support pins 66 and flexible heat transfer members 68 .

Movable element 154 is movable between a coupled position and a released position and has a side surface 154a extending along its direction of movement. The side surface 154 a corresponds to the cylindrical outer peripheral surface of the movable element 154 . The movable element 154 is inserted into the first heat transfer terminal portion 51 when moved from the released position to the coupled position. At this time, the movable element 154 comes into contact with the heat transfer terminal 60 of the first heat transfer terminal portion 51 at the side surface 154a, and spreads the heat transfer terminal 60 radially outward. Thereby, the heat transfer terminal 60 of the first heat transfer terminal portion 51 contacts the heat transfer terminal 60 of the second heat transfer terminal portion 52 . In this manner, the movable element 154 thermally couples the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 to each other when in the coupled position. The first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 are not thermally coupled via the movable element 154, but are directly thermally coupled by the contact of the respective heat transfer terminals 60. .

On the other hand, the movable element 154 is pulled out from the first heat transfer terminal portion 51 when moved from the coupled position to the released position. At this time, the heat transfer terminal 60 of the first heat transfer terminal portion 51 moves radially inward with respect to the terminal support member 62 due to the elastic restoring force of the elastic member 64 and is returned to the initial position. As a result, the heat transfer terminal 60 of the first heat transfer terminal portion 51 is separated from the heat transfer terminal 60 of the second heat transfer terminal portion 52 . In this way, the movable element 154 releases the thermal coupling between the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 when in the release position.

In the above-described embodiment described with reference to FIGS. 1 to 10, the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 are spaced apart in the axial direction (moving direction of the movable element 154). However, in the embodiment shown in FIGS. 13(a) and 13(b), the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 can be arranged at the same position in the axial direction. Thereby, a compact thermal switch 50 can be realized.

1 to 10, there are two thermal contact interfaces (the contact surface between the movable heat transfer element 54 and the first heat transfer terminal portion 51, and the movable heat transfer terminal portion 51). 13(a) and 13(b), only one contact surface (first heat transfer terminal 51 and only the contact surface of the second heat transfer terminal portion 52). This leads to improved heat transfer efficiency of the thermal switch 50 .

Furthermore, the embodiment shown in Figures 13(a) and 13(b) not only allows for a shorter initial cooling time, but is also advantageous for re-cooling after quenching. Since the movable element 154 can be thin and lightweight, the heat capacity can be reduced. Therefore, even if the movable element 154 is at room temperature when the thermal switch 50 is turned off, the heat input from the movable element 154 to the low temperature portion when the thermal switch 50 is turned on is small, and there is little effect on recooling.

The thermal switch 50 may be provided with a shutter 70 . Since thermal switch 50 is provided inside radiant heat shield 40 , shutter 70 may be provided outside radiant heat shield 40 . Shutter 70 is open when movable element 154 is in the coupled position and closed when movable element 154 is in the released position.

In the embodiment shown in FIGS. 13(a) and 13(b), the first heat transfer terminal portion 51 is thermally coupled with the first cooling stage 22a, and the second heat transfer terminal portion 52 is the second cooling stage 22a. Although it is thermally coupled to stage 22b, the reverse connection is also possible. That is, the first heat transfer terminal portion 51 may be thermally coupled to the second cooling stage 22b, and the second heat transfer terminal portion 52 may be thermally coupled to the first cooling stage 22a. In this case, the heat transfer terminal 60 of the first heat transfer terminal portion 51 is connected to the heat transfer member 42 by the flexible heat transfer member 68, and the heat transfer terminal 60 of the second heat transfer terminal portion 52 is connected by the flexible heat transfer member 68 to radiant heat. It may be connected to the shield 40 .

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

In the embodiment described above, the movable heat transfer element 54 is housed between the vacuum vessel 30 and the first heat transfer terminal portion 51 when the movable heat transfer element 54 is at the release position. Alternatively, for example, when the free space on the first heat transfer terminal portion 51 side is limited, the movable heat transfer element 54 is arranged on the second heat transfer terminal portion 52 side, and the movable heat transfer element It may be housed between the vacuum vessel 30 and the second heat transfer terminal portion 52 when 54 is in the released position.

In the above-described embodiment, both the first heat transfer terminal portion and the second heat transfer terminal portion are provided with the heat transfer terminal 60, but only one of the heat transfer terminal portions (for example, the first heat transfer terminal portion 51) is provided with the heat transfer terminal portion. A thermal terminal 60 may be provided. In this case, the other heat transfer terminal portion (for example, the second heat transfer terminal portion 52) is such that the tip of the movable heat transfer element 54 abuts against the heat transfer terminal portion as in the thermal switch 80 according to the comparative example. may be thermally coupled with the moveable heat transfer element 54 by a.

In some embodiments, thermal switch 50 may be provided separately from cryogenic refrigerator 20 . The thermal switch 50 for the cryogenic device 10 includes a first heat transfer terminal portion 51 that can be installed on either the cooling side or the cooled side of the cryogenic device 10 and the other of the cooling side or the cooled side of the cryogenic device 10. and the second heat transfer terminal portion 52 that can be installed in the joint position and the release position, and the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 are thermally connected when they are in the joint position. and a movable heat transfer element 54 that releases thermal coupling between the first heat transfer terminal portion 51 and the second heat transfer terminal portion 52 when in the release position.

Although the present invention has been described using specific terms based on the embodiment, the embodiment only shows one aspect of the principle and application of the present invention, and the embodiment does not include the claims. Many variations and rearrangements are permissible without departing from the spirit of the invention as defined in its scope.

10 cryogenic device 20 cryogenic refrigerator 22a first cooling stage 22b second cooling stage 50 thermal switch 51 first heat transfer terminal 52 second heat transfer terminal 54 moveable heat transfer element 54a Side surface 56 Operation unit 56a Rotation shaft 60 Heat transfer terminal 70 Shutter.

Claims (9)

a first cooling stage;
a second cooling stage cooled to a lower temperature than the first cooling stage;
a first heat transfer terminal thermally coupled to the first cooling stage;
a second heat transfer terminal thermally coupled to the second cooling stage;
It is movable between a coupling position and a releasing position, mediates thermal coupling between the first heat transfer terminal portion and the second heat transfer terminal portion when in the coupling position, and releases the second heat transfer terminal portion when in the releasing position. A cryogenic refrigerator, comprising: a movable heat transfer element with which thermal coupling between the first heat transfer terminal portion and the second heat transfer terminal portion is released. the moveable heat transfer element has a side surface extending along its direction of movement;
At least one of the first heat transfer terminal portion and the second heat transfer terminal portion is in contact with the side surface of the movable heat transfer element when the movable heat transfer element is in the coupled position, and the movable heat transfer element is 2. The cryogenic refrigerator of claim 1, further comprising heat transfer terminals that are out of contact with said side surfaces of said movable heat transfer element when in said released position. 3. The cryogenic refrigerator of claim 2, wherein the heat transfer terminals are resiliently pressed against the side surfaces of the moveable heat transfer element when the moveable heat transfer element is in the coupled position. It further has an operation part that can rotate around the rotation axis,
The cryogenic temperature according to any one of claims 1 to 3, wherein the movable heat transfer element is connected to the operating part so as to move along the axis of rotation when the operating part is rotated. refrigerator. A shutter provided between the first heat transfer terminal portion and the second heat transfer terminal portion, which is opened when the movable heat transfer element is in the coupling position and closed when the movable heat transfer element is in the release position. 5. A cryogenic refrigerator according to any one of claims 1 to 4, further comprising: The movable heat transfer element is also movable to a standby position, and is thermally coupled to the first heat transfer terminal portion and thermally coupled to the second heat transfer terminal portion when in the standby position. 6. The cryogenic refrigerator according to any one of claims 1 to 5, wherein is released. a first cooling stage;
a second cooling stage cooled to a lower temperature than the first cooling stage;
a movable heat transfer element thermally coupled with the first cooling stage;
a heat transfer terminal portion thermally coupled to the second cooling stage;
The movable heat transfer element is movable between a coupling position and a standby position, has a side surface extending along the movement direction, and is thermally connected to the heat transfer terminal portion at the side surface when in the coupling position. and is released from thermal coupling with the heat transfer terminal portion when in the standby position. A thermal switch for cryogenic equipment, comprising:
a first heat transfer terminal portion that can be installed on either the cooling side or the cooled side of the cryogenic device;
a second heat transfer terminal portion that can be installed on the other of the cooling side and the cooled side of the cryogenic device;
It is movable between a coupling position and a releasing position, mediates thermal coupling between the first heat transfer terminal portion and the second heat transfer terminal portion when in the coupling position, and releases the second heat transfer terminal portion when in the releasing position. A thermal switch for a cryogenic apparatus, comprising: a first heat transfer terminal portion and a movable heat transfer element that is thermally decoupled from each of the second heat transfer terminal portions. A thermal switch for cryogenic equipment, comprising:
a first heat transfer terminal portion that can be installed on either the cooling side or the cooled side of the cryogenic device;
a second heat transfer terminal portion that can be installed on the other of the cooling side and the cooled side of the cryogenic device;
It is movable between a coupling position and a releasing position, thermally couples the first heat transfer terminal portion and the second heat transfer terminal portion when in the coupling position, and thermally couples the first heat transfer terminal portion when in the releasing position. A thermal switch for a cryogenic apparatus, comprising: a movable element for releasing thermal coupling between a heat transfer terminal portion and the second heat transfer terminal portion.

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