JP2023034893A - Cryogenic device - Google Patents

Abstract

To improve a guide structure for guiding movements of a cold head with respect to a cold head storage sleeve.SOLUTION: A cryogenic device 10 comprises a sleeve 50, a cold head 22 and a guide structure 70. The guide structure 70 includes: a guide part which provided in a sleeve side flange 52; and a guided part which is provided in a cold head side flange 26 and guided by the guide part. A clearance in a lateral direction vertical to a movement direction of the cold head side flange 26 is provided between the guide part and the guided part. The clearance of the guide structure 70 is determined so as to prevent contacts of a single-step cooling stage 30, a double-step cooling stage 34 and the sleeve 50 caused by an inclination of the guided part with respect to the guide part, the inclination occurring while the single-step cooling stage 30 and the double-step cooling stage 34 of the cold head 22 are respectively separated from a single-step heat transfer stage 56 and a double-step heat transfer stage 60 of the sleeve 50.SELECTED DRAWING: Figure 1

Description

The present invention relates to cryogenic devices.

Conventionally, it is known to use a mounting structure with a sleeve to mount a cryogenic refrigerator to a cryogenic vacuum vessel such as a cryostat. An object to be cooled, such as a superconducting coil, is contained within the cryogenic vacuum vessel and is in thermal contact with the distal end of the sleeve. A cold head of the cryogenic refrigerator is mounted inside the sleeve and cools the object to be cooled through the sleeve.

During the long-term operation of a cryogenic refrigerator, maintenance of the cryogenic refrigerator may be required on a regular basis. The operator can lift the coldhead slightly from the sleeve, thereby breaking the thermal contact between the coldhead and the sleeve, and performing maintenance on the coldhead. The cold head is heated to a temperature convenient for maintenance work, such as room temperature, and then cooled again after the work is completed. By releasing the thermal contact, the object to be cooled can be kept at a low temperature. There is no need to heat up and recool the object to be cooled for maintenance of the cryogenic refrigerator. Therefore, it is possible to shorten the recooling time of the object to be cooled and shorten the time required for maintenance compared to the case where the temperature of the object to be cooled is raised to room temperature together with the cryogenic refrigerator and the maintenance is performed on the cryogenic refrigerator. be able to.

Japanese Patent Application Laid-Open No. 2005-123313

As a result of earnest research on the above-described cryogenic apparatus, the inventors of the present invention have come to recognize the following problems. A guide structure is provided for guiding movement of the coldhead relative to the coldhead receiving sleeve. The guiding structure has some clearance between the guiding part and the guided part. This clearance can cause the coldhead to tilt relative to the sleeve when the coldhead is lifted from the sleeve to break thermal contact. With tilting, the cooling stage at the end of the coldhead may contact the sleeve, possibly undesirably. Also, when the cold head is pressed against the sleeve, an unbalanced load may act on the cold head. The deformation of the cold head that can occur due to the unbalanced load affects the flow of refrigerant gas within the cold head and can reduce the refrigerating capacity of the cold head.

It is an exemplary object of some aspects of the present invention to provide improvements in guide structures for guiding movement of the coldhead relative to the coldhead-receiving sleeve.

According to one aspect of the invention, a cryogenic apparatus includes a coldhead containing sleeve comprising a sleeve side flange, a single heat transfer stage, a double heat transfer stage, a coldhead side flange, a single cooling stage, a two-stage cooling stage cooled to a lower temperature than the one-stage cooling stage, the one-stage cooling stage and the two-stage cooling stage being respectively the one-stage heat transfer stage and the two-stage heat transfer stage due to movement of the coldhead side flange relative to the sleeve side flange. and a guide structure for guiding movement of the cold head side flange with respect to the sleeve side flange. The guide structure includes a guide portion provided on the sleeve-side flange and a guided portion provided on the cold-head-side flange and guided by the guide portion, and provides a lateral clearance perpendicular to the moving direction of the cold-head-side flange. It is provided between the guide portion and the guided portion. The first cooling stage, the second cooling stage, and the cold head housing sleeve due to the inclination of the guided part with respect to the guiding part caused when the first cooling stage and the second cooling stage are separated from the first heat transfer stage and the second heat transfer stage, respectively. The clearance of the guide structure is defined so as to prevent the contact of the

According to one aspect of the invention, a cryogenic apparatus includes a coldhead containing sleeve comprising a sleeve side flange, a single heat transfer stage, a double heat transfer stage, a coldhead side flange, a single cooling stage, a two-stage cooling stage cooled to a lower temperature than the one-stage cooling stage, the one-stage cooling stage and the two-stage cooling stage being respectively the one-stage heat transfer stage and the two-stage heat transfer stage due to movement of the coldhead side flange relative to the sleeve side flange. and a guide structure for guiding movement of the cold head side flange with respect to the sleeve side flange. The guide structure includes a guide portion provided on the sleeve-side flange and a guided portion provided on the cold-head-side flange and guided by the guide portion, and provides a lateral clearance perpendicular to the moving direction of the cold-head-side flange. It is provided between the guide portion and the guided portion. The coldhead includes a dual stage cylinder connecting the single stage cooling stage to the dual stage cooling stage, and a dual stage displacer housed within the dual stage cylinder movably relative to the dual stage cylinder. The lateral gap between the two-stage cylinder and the two-stage displacer does not exceed the permissible upper limit of the gap under the unbalanced load acting on the cold head side flange when the two-stage cooling stage is pressed against the two-stage heat transfer stage. As such, the clearance of the guide structure is defined.

According to the present invention, an improvement can be provided in the guide structure for guiding movement of the coldhead relative to the coldhead receiving sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the cryogenic apparatus which concerns on embodiment. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows typically the cryogenic apparatus which concerns on embodiment. 1 is a top view schematically showing a cold head of a cryogenic refrigerator according to an embodiment; FIG. It is a figure which concerns on embodiment and shows typically the guide structure provided in the cryogenic apparatus. FIG. 4 is a schematic diagram showing a tilt that can occur in the guide structure according to the embodiment; 6(a) and 6(b) are schematic diagrams showing exemplary geometries of a two-stage cooling stage of a cold head, according to an embodiment. 7(a) and 7(b) are schematic diagrams showing an exemplary shape of a single cooling stage of a cold head, according to an embodiment. FIG. 4 is a schematic diagram showing an unbalanced load that can act on the cold head according to the embodiment; 9(a) and 9(b) are diagrams schematically showing another example of the guide structure according to the embodiment. FIGS. 10(a) and 10b) are diagrams schematically showing another example of the guide structure according to the embodiment. FIG. 5 is a diagram schematically showing another example of the guide structure according to the embodiment; FIG. 5 is a diagram schematically showing another example of the guide structure according to the 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.

1 and 2 are diagrams schematically showing a cryogenic apparatus according to an embodiment. FIG. 1 shows a state in which an object to be cooled in a cryogenic apparatus is thermally coupled with a cold head of a cryogenic refrigerator provided in the cryogenic apparatus, and FIG. A state in which the cold head and the object to be cooled are thermally decoupled is shown. FIG. 3 is a top view schematically showing the cold head of the cryogenic refrigerator according to the embodiment. FIG. 4 is a diagram schematically showing a guide structure provided in the cryogenic apparatus according to the embodiment.

The cryogenic apparatus 10 is installed in a vacuum vessel 12 , also called a cryostat, and used as a cooling source to provide a cryogenic environment within the vacuum vessel 12 . An object 14 to be cooled by the cryogenic device 10 is placed in the vacuum vessel 12 . The cryogenic apparatus 10, together with the vacuum vessel 12 and the object to be cooled 14, may form part of cryogenic equipment. Cryogenic equipment may be, for example, a single crystal puller, 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 equipment, in which case Coolant 14 may be a superconducting coil.

The cryogenic apparatus 10 comprises a cryogenic refrigerator 20 having a coldhead 22 and a compressor 24 and a coldhead containing sleeve (hereinafter simply sleeve) 50 . The sleeve 50 is installed in the vacuum vessel 12 so as to be combined with the vacuum vessel 12 to define a vacuum region 13 within the vacuum vessel 12 . The cold head 22 is attached to the sleeve 50 while being inserted into the sleeve 50 . Between the coldhead 22 and the sleeve 50 an airtight region 18 isolated from the ambient environment 16 is formed. Ambient environment 16 is, for example, a room temperature atmospheric pressure environment. The hermetic region 18 may be evacuated to a vacuum.

A compressor 24 of the cryogenic refrigerator 20 is provided for circulating a working gas (eg, helium gas) through the cryogenic refrigerator 20 . Compressor 24 is located in ambient environment 16 . The compressor 24 is configured to supply a high-pressure working gas to the cold head 22, recover from the cold head 22 a low-pressure working gas decompressed by adiabatic expansion in the expansion space in the cold head 22, and pressurize it again. ing.

Cryogenic refrigerator 20 is, by way of example, a two-stage Gifford-McMahon (GM) refrigerator. Thus, the coldhead 22 includes a coldhead side flange 26 , a single cylinder 28 , a single cooling stage 30 , a double cylinder 32 and a double cooling stage 34 . These components of coldhead 22 are arranged along the central axis of coldhead 22 in the order of this description. Coldhead flange 26 is positioned in ambient environment 16 , and single cylinder 28 , single cooling stage 30 , double cylinder 32 , and double cooling stage 34 are positioned in airtight region 18 .

A single stage cylinder 28 connects the coldhead flange 26 with a single cooling stage 30 and a dual stage cylinder 32 connects the single cooling stage 30 with a secondary cooling stage 34 . Typically, the first stage cylinder 28 and the second stage cylinder 32 are hollow cylindrical members that extend coaxially with the central axis of the coldhead 22 , with the first stage cylinder 28 having a larger diameter than the second stage cylinder 32 . The cold head side flange 26, the first stage cylinder 28 and the second stage cylinder 32 are made of metal such as stainless steel.

A first stage cooling stage 30 is secured to the end of the first stage cylinder 28 axially opposite the coldhead flange 26 and has a shorter axial length than the first stage cylinder 28 . The two-stage cooling stage 34 is fixed to the end of the two-stage cylinder 32 axially opposite to the one-stage cooling stage 30 and has a shorter axial length than the two-stage cylinder 32 . Single cooling stage 30 and dual cooling stage 34 typically have a cylindrical profile coaxial with the central axis of coldhead 22 , with single cooling stage 30 having a larger diameter than dual cooling stage 34 . The single cooling stage 30 and the double cooling stage 34 are made of a highly thermally conductive metal such as copper (eg, pure copper) or other thermally conductive material. The thermal conductivity of the thermally conductive material forming the cooling stage is higher than that of the material forming the cylinder.

The coldhead 22 further comprises a single-stage displacer 36 and a dual-stage displacer 38 connected at their ends and a drive 40 for axially driving the displacers.

A single-stage displacer 36 and a dual-stage displacer 38 extend coaxially with the central axis of the coldhead 22 and are axially movably disposed within the single-stage cylinder 28 and the dual-stage cylinder 32, respectively. The one-stage displacer 36 and the two-stage displacer 38 contain cold storage materials. A first-stage expansion space for the working gas is formed between the first-stage displacer 36 and the first-stage cooling stage 30 in the first-stage cylinder 28, and the working gas is expanded between the second-stage displacer 38 and the second-stage cooling stage 34 in the second-stage cylinder 32. A two-stage expansion space is formed.

The drive unit 40 includes an electric motor that outputs rotation and a motion conversion mechanism such as a scotch yoke mechanism that converts this rotation into linear reciprocating motion. This motion converting mechanism is connected to the single-stage displacer 36 on the side axially opposite to the double-stage displacer 38 . Therefore, by driving the electric motor, the single-stage displacer 36 and the two-stage displacer 38 can be axially reciprocated via the motion conversion mechanism.

Further, the drive unit 40 incorporates a valve that controls the pressure in the expansion space. The pressure control valve is configured to alternately switch between supplying high pressure working gas from the compressor 24 to the expansion space via the regenerator and recovering low pressure working gas from the expansion space to the compressor 24 via the regenerator. ing. The drive unit 40 is configured to appropriately synchronize the volume change of the expansion space caused by the axial reciprocating motion of the single-stage displacer 36 and the two-stage displacer 38 and the pressure change of the expansion space caused by the pressure control valve. By operating the cryogenic refrigerator 20 in this manner, the first cooling stage 30 is cooled to a first cooling temperature, such as 30K to 80K, and the second cooling stage 34 is cooled to a second cooling temperature lower than the first cooling temperature, For example, it is cooled to 3K to 20K.

The drive 40 is positioned in the environment 16 with the coldhead flange 26 and is secured to the coldhead flange 26 on the side opposite the first stage cylinder 28 by fasteners (not shown) such as bolts. When performing maintenance on the cryogenic refrigerator 20, the connection between the drive unit 40 and the cold head side flange 26 can be released. Thereby, the single-stage displacer 36 and the two-stage displacer 38 can be pulled out from the single-stage cylinder 28 and the two-stage displacer 32 respectively, and the drive section 40 can be removed from the cold head 22 integrally with the single-stage displacer 36 and the two-stage displacer 38 .

If the cryogenic refrigerator 20 is two-stage, the sleeve 50 is correspondingly configured two-stage. Thus, the sleeve 50 includes a sleeve side flange 52 , a single sleeve body 54 , a single heat transfer stage 56 , a double sleeve body 58 and a double heat transfer stage 60 . These components of sleeve 50 are arranged in the order listed along the central axis of coldhead 22 .

A single sleeve body 54 connects the sleeve side flange 52 with the single heat transfer stage 56 , and a double sleeve body 58 connects the single heat transfer stage 56 with the double heat transfer stage 60 . The single-stage sleeve body 54 and the two-stage sleeve body 58 are hollow cylindrical members extending coaxially with the central axis of the cold head 22 , and the single-stage sleeve body 54 has a larger diameter than the two-stage sleeve body 58 . The sleeve-side flange 52, the first-stage sleeve body 54, and the first-stage heat transfer stage 56 are made of metal such as stainless steel.

Single-stage sleeve body 54 and double-stage sleeve body 58 are arranged to surround single-stage cylinder 28 and double-stage cylinder 32, respectively. The diameter of the single stage sleeve body 54 is somewhat larger than the diameter of the single stage cylinder 28, and there is a gap between the single stage sleeve body 54 and the single stage cylinder 28 so that they do not contact each other. Similarly, the diameter of the double sleeve body 58 is somewhat larger than the diameter of the double cylinder 32, and there is a gap between the double sleeve body 58 and the double cylinder 32 so that they do not touch each other.

A first heat transfer stage 56 is secured to an end of the first sleeve body 54 axially opposite the sleeve-side flange 52 , and a second heat transfer stage 60 is axially opposite the first heat transfer stage 56 . It is secured to the end of the step sleeve body 58 . A through opening is formed in the center of the first-stage heat transfer stage 56 to connect the inner space of the first-stage sleeve body 54 to the inner space of the second-stage sleeve body 58 . The two-stage cylinder 32 and the two-stage cooling stage 34 of the cold head 22 are inserted into the inner space of the two-stage sleeve body 58 through this opening. Single heat transfer stage 56 and double heat transfer stage 60 are made of a highly heat conductive metal such as copper (eg, pure copper) or other heat conductive material. The thermal conductivity of the thermally conductive material forming the heat transfer stage is higher than the thermal conductivity of the material forming the sleeve body.

Single heat transfer stage 56 is thermally coupled to single cooling stage 30 by physical contact with single cooling stage 30 . Dual heat transfer stage 60 is thermally coupled with dual cooling stage 34 through physical contact with dual cooling stage 34 . In this embodiment, the contact surface between the heat transfer stage and the cooling stage is flat. However, the cooling stage may be provided with a non-flat surface such as a tapered surface, an inclined surface, or an uneven surface, and the heat transfer stage may be provided with a non-flat surface corresponding to this non-flat surface. . Also, the heat transfer stage and the cooling stage may be in direct contact, or may be in thermal contact with a soft intervening layer, such as an indium sheet, that aids in good heat transfer.

An object to be cooled other than the object to be cooled 14 (for example, a heat shield surrounding the object to be cooled 14) is attached to the outer surface of the one-stage heat transfer stage 56 exposed to the vacuum region 13, or an appropriate heat transfer member is attached. are thermally coupled via Therefore, when the first cooling stage 30 is in contact with the first heat transfer stage 56 , the first cooling stage 30 can cool the first cooling object to the first cooling temperature via the first heat transfer stage 56 . can. Also, the object to be cooled 14 is attached to the outer surface of the two-stage heat transfer stage 60 exposed to the vacuum region 13, or is thermally coupled via an appropriate heat transfer member. Thus, the object to be cooled 14 is cooled to the second cooling temperature by the two-stage cooling stage 34 via the two-stage heat transfer stage 60 when the two-stage cooling stage 34 is in contact with the two-stage heat transfer stage 60. be able to.

A sleeve-side flange 52 is positioned in the ambient environment 16 and is coupled to the coldhead-side flange 26 . As an example, the sleeve-side flange 52 is fixed to an opening formed in the top plate of the vacuum vessel 12, and the first-stage sleeve body 54 and the two-stage sleeve body 58 extend into the vacuum vessel 12 from this opening. Therefore, the cold head 22 is installed in the vacuum vessel 12 with its central axis parallel to the vertical direction, with the drive unit 40 directed upward and the cooling stage directed downward. However, the installation orientation of the cold head 22 is not limited to such vertical orientation, and may be installed in other orientations such as horizontal orientation or oblique orientation. The sleeve 50 may be formed on any surface such as the side or bottom of the vacuum vessel 12 .

As an exemplary configuration, the sleeve side flange 52 includes a first annular flange 52a to which the cold head side flange 26 is attached, a second annular flange 52b fixed to the vacuum vessel 12, and the first flange 52a. and a cylindrical outer tube portion 52c that connects the second flange 52b. The first flange 52a, the second flange 52b, and the outer cylindrical portion 52c are arranged coaxially with the central axis of the cold head 22. As shown in FIG. The second flange 52b extends radially outward from the end of the first-stage sleeve body 54, the outer cylindrical portion 52c extends from the second flange 52b in the axial direction opposite to the first-stage sleeve body 54, and the first flange 52a It extends radially outward from the end portion of the outer cylindrical portion 52c on the side opposite to the second flange 52b in the axial direction.

The coldhead flange 26 is a combination of two flanges, a main flange 42 and a transition flange 44 . A main flange 42 extends radially outwardly from an end of the first stage cylinder 28 axially opposite the first stage cooling stage 30 . The main flange 42 may be integrally formed with the first stage cylinder 28 .

A transition flange 44 is secured to the main flange 42 and mates with the sleeve-side flange 52 to form an airtight region 18 between the sleeve 50 and the coldhead 22 . The transition flange 44 has an annular flange portion 44a and a cylindrical inner cylinder portion 44b. The flange portion 44a is fixed to the lower surface of the main flange 42 (the surface on the opposite side of the driving portion 40 in the axial direction) by a fastening member (not shown) such as a bolt. facing each other with a gap in the direction. The inner cylindrical portion 44 b extends from the inner peripheral portion of the flange portion 44 a in the axial direction opposite to the main flange 42 and is inserted into the outer cylindrical portion 52 c of the sleeve-side flange 52 . The inner tubular portion 44 b surrounds the upper end of the first stage cylinder 28 .

The outer cylindrical portion 52c of the sleeve-side flange 52 is arranged immediately outside and adjacent to the inner cylindrical portion 44b of the transition flange 44. As shown in FIG. The diameter of the outer cylindrical portion 52c is larger than the diameter of the inner cylindrical portion 44b by, for example, several millimeters. . A seal member 46 for maintaining the airtightness of the airtight region 18 is arranged between the outer tubular portion 52c and the inner tubular portion 44b. The sealing member 46 is, for example, a sealing member such as an O-ring arranged in a circumferential groove formed in the inner cylindrical portion 44b. In the illustrated example, the seal member 46 is attached to the inner tubular portion 44b, but may be attached to the outer tubular portion 52c.

The cryogenic apparatus 10 also includes a guide structure 70 that guides movement of the coldhead flange 26 relative to the sleeve flange 52 . As shown in FIG. 3, the guide structures 70 are provided at a plurality of locations on the cold head side flange 26, four locations in this example. The guide structures 70 may be circumferentially arranged at equal angular intervals (for example, every 90 degrees) on the cold head side flange 26 so as to surround the driving portion 40 of the cold head 22 .

The guide structure 70 includes a guide portion provided on the sleeve-side flange 52 and a guided portion provided on the cold-head-side flange 26 and guided by the guide portion. In this embodiment, a guide pin 72 is provided on the sleeve-side flange 52 as a guide portion. As a guided portion, a guide hole 74 into which a guide pin 72 is inserted is provided in the cold head side flange 26 .

As shown in FIG. 4 , the guide pin 72 is a cylindrical projection erected on the first flange 52 a of the sleeve-side flange 52 and extending toward the cold-head-side flange 26 . The guide hole 74 is a circular through hole into which the guide pin 72 is inserted, and is provided in the transition flange 44 in this embodiment.

The guide structure 70 has a lateral clearance d _G between the guide pin 72 and the guide hole 74 perpendicular to the direction of movement of the coldhead flange 26 . That is, the clearance d _G is the radial gap between the guide pin 72 and the guide hole 74. When the diameter of the guide pin 72 is φG and the diameter of the guide hole 74 is φG _m , d _G =(φG _m −φG). /2.

In this embodiment, the clearance d _G of the guide structure 70 is greater than the clearance C ₁ in the seal member 46 , that is, the radial gap between the inner tubular portion 44 b of the transition flange 44 and the outer tubular portion 52 c of the sleeve-side flange 52 . may be smaller. According to typical O-ring designs, the O-ring crush rate is selected, for example, in the range of 8% to 30%. Therefore, if the seal member 46 is an O-ring, and the thickness of the O-ring is, for example, 3 mm, the clearance _C1 is selected from the range of 0.24 mm to 0.9 mm. The clearance _dG of the guide structure 70 may be smaller than the selected clearance _C1 (eg 0.9mm).

With this configuration, even if the transition flange 44 is displaced from the central axis of the cold head 22 and the seal member 46 is locally deformed, the inner cylindrical portion 44 b of the transition flange 44 is positioned outside the sleeve-side flange 52 . The flange portion 44a of the transition flange 44 hits the guide pin 72 through the guide hole 74 before hitting the cylindrical portion 52c. Thus, the guide structure 70 can act as a mechanical stopper against radial displacement of the cold head 22 due to deformation of the seal member 46 .

A through hole 76 that is axially continuous with the guide hole 74 is formed in the main flange 42 . The guide pin 72 is inserted from the guide hole 74 into the through hole 76 . In this embodiment, the lateral clearance C ₂ formed between the main flange 42 and the guide pin 72, i.e., the radial gap between the guide pin 72 and the through hole 76, is greater than the clearance _dG of the guide structure 70. big.

In this way, it becomes easy to align the central axis defined by the plurality of guide structures 70 with the center of the seal member 46 . In contrast, if the guide hole 74 were provided in the main flange 42 , assembly errors between the main flange 42 and the transition flange 44 would cause the center axis defined by the guide structure 70 to be displaced from the center of the seal member 46 . It is disadvantageous because

Note that the guide holes 74 may be provided in the main flange 42 if assembly errors can be sufficiently reduced by assembling the main flange 42 and the transition flange 44 accurately. In this case, the through hole formed in the transition flange 44 into which the guide pin 72 is inserted may have a larger diameter than the guide hole 74 of the main flange 42 . Alternatively, the through hole of the transition flange 44 and the guide hole 74 of the main flange 42 may have the same diameter.

The coldhead flange 26 may be provided with an alignment structure 78 to assist in the correct assembly of the main flange 42 and the transition flange 44 . As an example of the shaft alignment structure 78, as shown in FIG. 4, a convex portion provided on the outermost peripheral portion of the flange portion 44a of the transition flange 44 may be engaged with the outer peripheral surface of the main flange 42. As shown in FIG. By fitting the main flange 42 into the protrusion of the transition flange 44 during assembly, the respective centers of the main flange 42 and the transition flange 44 can be easily aligned.

As shown in FIG. 3 , flange fastening members 48 such as bolts are provided at a plurality of locations on the cold head side flange 26 so as to surround the driving portion 40 of the cold head 22 . The flange fastening member 48 is screwed into a bolt hole of the sleeve side flange 52 through an insertion hole or a notch formed in the cold head side flange 26 , and can fasten the cold head side flange 26 and the sleeve side flange 52 . . When the flange fastening member 48 is released, the coldhead flange 26 is axially movable relative to the sleeve flange 52 along the guide structure 70 .

As an exemplary arrangement, the flange fastening members 48 may be arranged on the same circumference as the guide structure 70 on the coldhead flange 26, with at least one flange fastening member 48 (two in the example shown). may be provided between circumferentially adjacent guide structures 70 . Although not shown in FIG. 3 for the sake of simplicity, the cold head side flange 26 is also provided with a fastening member for fastening the main flange 42 and the transition flange 44 together.

In the cryogenic apparatus 10 according to the embodiment, as described below, the single cooling stage 30 and the double cooling stage 34 are respectively connected to the single heat transfer stage 56 and the double cooling stage 34 by movement of the coldhead flange 26 relative to the sleeve flange 52 . It contacts or separates from the stage heat transfer stage 60 .

When the timing when the maintenance of the cryogenic refrigerator 20 is permitted arrives, the cooling operation of the cryogenic refrigerator 20 is stopped. At this time, single cooling stage 30 is in physical and thermal contact with single heat transfer stage 56, and dual cooling stage 34 is in physical and thermal contact with dual heat transfer stage 60, as shown in FIG. in contact.

First, the operator removes the flange fastening member 48 to release the fastening between the cold head side flange 26 and the sleeve side flange 52 . Cold head flange 26 is lifted from sleeve flange 52 along guide structure 70 and cold head 22 is lifted from sleeve 50 . This lifting height L _C is about several mm, for example, about 2 to 3 mm. As shown in FIG. 2, single cooling stage 30 and dual cooling stage 34 are spaced apart from single heat transfer stage 56 and dual heat transfer stage 60, respectively, to break thermal contact. A sealing member 46 is provided between the coldhead flange 26 and the sleeve flange 52 so that the isolation of the gas tight region 18 from the surrounding environment 16 is maintained. It is possible to raise the temperature of the cold head 22 while keeping the object 14 to be cooled at a low temperature.

Maintenance of the cryogenic refrigerator 20 is performed. The drive portion 40 of the coldhead 22 is removed from the coldhead 22 along with the single stage displacer 36 and the dual stage displacer 38 . Single cylinder 28 , single cooling stage 30 , double cylinder 32 , and double cooling stage 34 are mounted directly on sleeve 50 . The serviced (or new) drive and displacer are then attached to the coldhead 22 . Then, the cooling operation of the cryogenic refrigerator 20 is resumed.

The coldhead flange 26 is then pushed along the guide structure 70 into the sleeve flange 52, and the single cooling stage 30 and the double cooling stage 34 are reconnected with the single heat transfer stage 56 and the double heat transfer stage 60, respectively. Contact. Flange fastening member 48 refastens coldhead flange 26 and sleeve flange 52, and as shown in FIG. It is pressed against the heat transfer stage 60 and is in thermal contact again.

FIG. 5 is a schematic diagram showing a tilt that can occur in the guide structure 70 according to the embodiment. The guide structure 70 has a clearance _dG between the guide pin 72 of the sleeve side flange 52 and the guide hole 74 of the coldhead side flange 26 as described above. Therefore, when the cold head side flange 26 is lifted from the sleeve side flange 52 , the guide holes 74 can be inclined with respect to the guide pins 72 . The tilt angle θ at the maximum tilt is θ=tan ⁻¹ (2d _G /L _G ).

Here, _LG represents the length of the guide structure 70 and represents the depth of the guide hole 74 provided in the cold head flange 26 . When the guide hole 74 is formed in the flange portion 44a of the transition flange 44 as in the above example, the length _LG of the guide structure 70 corresponds to the thickness of the flange portion 44a of the transition flange 44. FIG.

Thus, tilting of the guide structure 70 when the coldhead flange 26 is lifted from the sleeve flange 52 causes the coldhead 22 to tilt relative to the sleeve 50 . If the angle of inclination is large, the coldhead 22 may contact or collide with the sleeve 50, which may cause inconvenience. For example, if the cooling stage of the coldhead 22 is provided with a temperature sensor, the wiring to the temperature sensor would be placed around the coldhead 22 , but such wiring would be displaced when the coldhead 22 contacts the sleeve 50 . It can get caught and damaged. Similar damage risks may exist if other sensors are placed in the airtight area 18 . Also, the cooling stage of the coldhead 22 has a contact interface that contacts the heat transfer stage of the sleeve 50 , and this contact interface may be damaged when the coldhead 22 contacts the sleeve 50 . It is desirable to avoid such concerns.

Therefore, in this embodiment, the inclination of the guide hole 74 with respect to the guide pin 72 that occurs when the single-stage cooling stage 30 and the two-stage cooling stage 34 are separated from the single-stage heat transfer stage 56 and the two-stage heat transfer stage 60 respectively. A clearance _dG of the guide structure 70 is defined to prevent contact between the cooling stage 30 and the two-stage cooling stage 34 and the sleeve 50 .

According to the study of the present inventors, one of the parts with a high risk of contact or collision due to inclination in the guide structure 70 is the two-stage cooling stage 34 and the two-stage sleeve body 58 . Therefore, the guide structure 70 is designed so that the amount of lateral movement of the two-stage cooling stage 34 due to the inclination of the guide hole 74 with respect to the guide pin 72 does not exceed the lateral distance between the two-stage cooling stage 34 and the two-stage sleeve body 58 . A clearance _dG may be defined.

The maximum amount of lateral movement of the two-stage cooling stage 34 can be expressed as L _R sin θ. Here, L _R corresponds to the axial length of the cold head 22, and is the length from the lower surface of the main flange 42 of the cold head 22 to the end surface of the two-stage cooling stage 34 (the contact surface with the two-stage heat transfer stage 60). Distance. The tilt angle θ is θ=tan ⁻¹ (2d _G /L _G ) as described above.

Note that it can be expressed as L _R =L _A +L _B. As shown in FIG. 2, L _A corresponds to the length of the two-stage cylinder 32, and is the distance from the end surface of the first-stage cooling stage 30 (the contact surface with the first-stage heat transfer stage 56) to the end surface of the two-stage cooling stage 34. is. _LB corresponds to the length of the first stage cylinder 28 and is the distance from the lower surface of the main flange 42 of the cold head 22 to the end surface of the first stage cooling stage 30 .

The lateral spacing between the dual cooling stage 34 and the dual sleeve body 58 can be expressed as (D _s −D _h2 )/2, where D _h2 is the outer diameter of the dual cooling stage 34 and D _s represents the inner diameter of the two-stage sleeve body 58 .

Therefore, the clearance _dG of the guide structure 70 may be determined so as to satisfy the following formula (1).
L _R sin(tan ⁻¹ (2d _G /L _G ))<(D _s −D _h2 )/2 (1)

6(a) and 6(b) are schematic diagrams showing exemplary shapes of the two-stage cooling stage 34 of the cold head 22 according to the embodiment. As shown in FIG. 6A, the two-stage cooling stage 34 may have a columnar shape with a constant outer diameter in the axial direction. In this case, the outer diameter _Dh2 of the two-stage cooling stage 34 is 46 mm in the commonly available cold head 22 (for example, a 4KGM refrigerator manufactured by Sumitomo Heavy Industries, Ltd.). In addition, as shown in FIG. 6(b), the two-stage cooling stage 34 may have a flange portion at its end, and this flange portion has a larger diameter than other portions of the two-stage cooling stage 34. It is In this case, in the generally available cold head 22 (for example, a 4KGM refrigerator manufactured by Sumitomo Heavy Industries, Ltd.), the outer diameter D _h2 of the two-stage cooling stage 34 (that is, the diameter of the flange portion) is 64 mm. Therefore, it can be said that the outer diameter D _h2 of the two-stage cooling stage 34 is typically in the range of 46 mm to 64 mm.

Moreover, the inner diameter _Ds of the two-stage sleeve body 58 is not desired to be excessively large from the viewpoint of reducing the amount of heat input to the two-stage cooling stage 34 due to heat conduction through the two-stage sleeve body 58 . As a guideline, the inner diameter D _s of the double sleeve body 58 may be smaller than the outer diameter of the single cooling stage 30 of the coldhead 22 . The outer diameter of the single cooling stage 30 is typically 90 mm. Therefore, the inner diameter _Ds of the two-stage sleeve body 58 may be selected from the range of 50 mm to 90 mm. Thus, the lateral spacing (D _s −D _h2 )/2 between the dual cooling stage 34 and the dual sleeve body 58 can be in the range of 2 mm to 22 mm.

The length _LG of the guide structure 70 may for example be selected from the range 5 mm to 50 mm, for example from the range 10 mm to 15 mm. The axial length L _R of the cold head 22 may be selected from the range of 360 mm to 440 mm, for example.

Considering an example where (D _s −D _h2 )/2 is 22 mm and the axial length L _R of the cold head 22 is 392.5 mm, when the length L _G of the guide structure 70 is 10 mm, the above formula (1 ) is about 0.25 _mm or less. When the length _LG of the guide structure 70 is, for example, 12 mm, the above equation (1) is satisfied if the clearance d _G of the guide structure 70 is about 0.3 mm or less. When the length _LG of the guide structure 70 is, for example, 13 mm, the above equation (1) is satisfied if the clearance d _G of the guide structure 70 is about 0.35 mm or less. When the length L _G of the guide structure 70 is 15 mm, the above equation (1) is satisfied if the clearance d _G of the guide structure 70 is about 0.4 mm or less.

Thus, the upper limit of the clearance _dG of the guide structure 70 can be determined based on the above formula (1). This prevents contact between the two-stage cooling stage 34 and the two-stage sleeve body 58 due to the inclination of the guide holes 74 with respect to the guide pins 72 that occurs when the cold head 22 is lifted from the sleeve 50 .

According to the study of the present inventors, another part where the risk of contact or collision due to tilting in the guide structure 70 is high is the single-stage cooling stage 30 and the single-stage heat transfer stage 56 . Therefore, the guide structure 70 is designed so that the amount of downward movement of the edge portion 30a of the first stage cooling stage 30 due to the inclination of the guide hole 74 with respect to the guide pin 72 does not exceed the lift height _LC of the cold head side flange 26 with respect to the sleeve side flange 52. A clearance _LG of may be defined.

FIGS. 7(a) and 7(b) are schematic diagrams showing exemplary shapes of the single-stage cooling stage 30 of the cold head 22 according to the embodiment. As shown in FIG. 7A, the single-stage cooling stage 30 may have a columnar shape with a constant outer diameter in the axial direction. In this case, the outer diameter _Dh1 of the single-stage cooling stage 30 is 90 mm in the generally readily available cold head 22 (for example, a 4KGM refrigerator manufactured by Sumitomo Heavy Industries, Ltd.).

In addition, as shown in FIG. 7B, the first-stage cooling stage 30 may have a flange portion in the axially intermediate portion, and this flange portion has a larger diameter than other portions of the first-stage cooling stage 30. It is In this case, in the generally readily available cold head 22 (for example, a 4KGM refrigerator manufactured by Sumitomo Heavy Industries, Ltd.), the outer diameter D _h1 (that is, the diameter of the flange portion) of the first-stage cooling stage 30 is about 125 mm. There are many.

The amount of downward movement of the edge portion 30a of the single-stage cooling stage 30 due to the inclination of the guide hole 74 with respect to the guide pin 72 can be expressed as (D _h1 /2) sin θ+L _B cos θ−L _B. Therefore, the clearance _dG of the guide structure 70 may be determined so as to satisfy the following formula (2).
(D _h1 /2) sin θ+L _B cos θ−L _B <L _C (2)
Here, the tilt angle θ is θ=tan ⁻¹ (2d _G /L _G ) as described above.

As an example, if the lift height L _C is 2 mm, the length L _B of the first stage cylinder 28 is 192.5 mm, and the outer diameter D _h1 of the first stage cooling stage 30 is 125 mm, then the length L _G of the guide structure 70 is is 10 mm, the clearance d _G of the guide structure 70 that satisfies the above equation (2) is about 0.15 mm or less. When the length L _G of the guide structure 70 is 15 mm, the above equation (2) is satisfied if the clearance d _G of the guide structure 70 is about 0.25 mm or less.

Thus, the upper limit of the clearance _dG of the guide structure 70 can be determined based on the above formula (2). This prevents contact between the first cooling stage 30 and the first heat transfer stage 56 due to the inclination of the guide holes 74 with respect to the guide pins 72 that occurs when the cold head 22 is lifted from the sleeve 50 .

A lower limit of the clearance _dG of the guide structure 70 may be determined from the viewpoint of allowing the guide hole 74 to slide with respect to the guide pin 72 . The clearance _dG of the guide structure 70 may for example be greater than 0.01 mm (or such as 0.04 mm or such as 0.06 mm).

By the way, unlike when the cold head 22 is lifted from the sleeve 50, when the cold head 22 is pressed against the sleeve 50, the cooling stage of the cold head 22 is in close contact with the heat transfer stage of the sleeve 50. No contact or collision with the sleeve 50 due to the tilting of the cold head 22 occurs. However, according to the study of the present inventors, there is another concern caused by an unbalanced load that may act on the cold head side flange 26 when pressing the cold head 22 against the sleeve 50 . The offset load may deform the cold head 22 and locally enlarge the gap between the two-stage cylinder 32 and the two-stage displacer 38 . As a result, the working gas flow in the two-stage cylinder 32, which should normally pass through the cold storage material in the two-stage displacer 38, bypasses the cold storage material and passes through this gap. may lower the

Therefore, the lateral gap between the two-stage cylinder 32 and the two-stage displacer 38 is affected by the offset load acting on the cold head flange 26 when the two-stage cooling stage 34 is pressed against the two-stage heat transfer stage 60. The clearance _dG of the guide structure 70 may be determined so as not to exceed the allowable upper limit of the gap.

FIG. 8 is a schematic diagram showing an unbalanced load that can act on the cold head 22 according to the embodiment. The deformation of the cold head 22 due to the lateral biased load W acting on the cold head side flange 26 can be estimated using a beam model with the two-stage cooling stage 34 as a fixed end, as shown in FIG.

dA _max is the allowable upper limit of the gap between the two-stage cylinder 32 and the two-stage displacer 38, d _i is the initial value of the gap between the two-stage cylinder 32 and the two-stage displacer 38, ) is expressed as δ _A , it is sufficient if δ _A +d _i ≦dA _max holds.

Based on the beam model of FIG. 8, δ _B =X δ _A. Here, δ _B represents the lateral displacement of the cold head flange 26 due to the unbalanced load W. The first-stage cylinder 28 and the second-stage cylinder 32 have the same Young's modulus E, and the moment of inertia I of a cylinder having an outer diameter D and an inner diameter d is I=1/64×π×(D ⁴ −d ⁴ ). Using, the factor X is calculated as X=(2β+6αβ+6α ² β+2α ³ )/(2β+3αβ). where α=L _B /L _A , β=I _B /I _A =(Φ _B ⁴ −φ _B ⁴ )/(Φ _A ⁴ −φ _A ⁴ ), where Φ _A and Φ _A are two-stage cylinders 32 and φ _B and φ _B are the outer and inner diameters of the single stage cylinder 28 .

Since the cold head flange 26 can be laterally displaced by the clearance d _G of the guide structure 70 at maximum, δB≦d _G (=(φG _m −φG)/2).

Therefore, the clearance _dG of the guide structure 70 may be determined so as to satisfy the following formula (3).
_dG /X+di≦dAmax (3)

In order to prevent the working gas of the cryogenic refrigerator 20 from flowing linearly in the axial direction through the gap between the two-stage cylinder 32 and the two-stage displacer 38, it is known that the gap is preferably 0.03 mm or less. there is Therefore, the allowable upper limit of the gap between the two-stage cylinder 32 and the two-stage displacer 38, dA _max , can be set to 0.03 mm. In addition, 0.01 mm is adopted as a typical example of the initial value of the gap _di , and the first-stage cylinder 28 and the two-stage cylinder of a commonly available cold head 22 (for example, a 4KGM refrigerator manufactured by Sumitomo Heavy Industries, Ltd.) 32 lengths L _B , L _A , outer diameters Φ _B , Φ _A , inner diameters φ _B , φ _A , the upper limit of φG _m −φG (=2d _G ) is 0. 0.1 mm.

Thus, the upper limit of the clearance _dG of the guide structure 70 can be determined based on the above formula (3). As a result, it is possible to prevent the cooling capacity of the cold head 22 from deteriorating due to an unbalanced load that may act on the cold head 22 when pressed.

FIGS. 9A and 9B are diagrams schematically showing another example of the guide structure 70 according to the embodiment. 9(a) shows a state in which the cold head side flange 26 is pressed against the sleeve side flange 52, and FIG. 9(b) shows a state in which the cold head side flange 26 is lifted from the sleeve side flange 52. is shown. That is, in FIG. 9(a), the single cooling stage 30 and the double cooling stage 34 are in contact with the single heat transfer stage 56 and the double heat transfer stage 60, respectively, and in FIG. A stage cooling stage 34 is spaced apart from the single stage 56 and dual stage 60 heat transfer stages, respectively.

The guide structure 70 has a tapered guide pin 72 on the sleeve side flange 52, the guide pin 72 having a larger diameter at the root fixed to the sleeve side flange 52 and a smaller diameter at the tip. A guide hole 74 of the cold head side flange 26 into which the guide pin 72 is inserted has a constant inner diameter.

Therefore, as shown in the figure, when the guide hole 74 is pushed all the way to the root of the guide pin 72, the clearance of the guide structure 70 has a first magnitude _dG1 and extends to the tip of the guide pin 72. With the guide hole 74 raised, the clearance of the guide structure 70 has a second magnitude _dG2 , the first magnitude _dG1 being less than the second magnitude _dG2 .

In this way, the cold head side flange 26 is pressed against the sleeve side flange 52, that is, the first cooling stage 30 and the second cooling stage 34 are brought into contact with the first heat transfer stage 56 and the second heat transfer stage 60, respectively. In the compressed state, the guide structure 70 can act as a mechanical stop against radial displacement of the cold head 22 due to deformation of the seal member 46 .

FIGS. 10(a) and 10(b) are diagrams schematically showing another example of the guide structure 70 according to the embodiment. FIG. 10(a) shows the state where the cold head side flange 26 is pressed against the sleeve side flange 52, and FIG. 10(b) shows the state where the cold head side flange 26 is lifted from the sleeve side flange 52. is shown.

In this example, a guide pin 72 is provided as a guided portion in the cold head side flange 26, and a guide hole 74 into which the guide pin 72 is inserted is provided in the sleeve side flange 52 as a guide portion. The guide pin 72 has a constant diameter in the axial direction and is inserted into the guide hole 74 . The guide hole 74 has a tapered hole shape, the inner diameter of which is smaller at the deeper part of the guide hole 74 and larger at the entrance part.

Thus, as shown, with the guide pin 72 pushed deep into the guide hole 74 , the clearance of the guide structure 70 has a first magnitude d _G1 and the guide pin 72 is positioned at the entrance of the guide hole 74 . The clearance of the guide structure 70 has a second magnitude _dG2 when lifted to the top, the first magnitude _dG1 being less than the second magnitude _dG2 .

In this way, the cold head side flange 26 is pressed against the sleeve side flange 52, i.e., the single cooling stage 30 and the double cooling stage 34 are connected to the single heat transfer stage 56 and the double cooling stage 34, respectively. While in contact with and pressed against the heat transfer stage 60 , the guide structure 70 can act as a mechanical stop against radial displacement of the cold head 22 due to deformation of the seal member 46 .

In the guide structure 70 shown in FIGS. 9 and 10, the first magnitude _dG1 of the clearance of the guide structure 70 may be determined such that the above formula (3) is satisfied. Also, the second magnitude _dG2 of the clearance of the guide structure 70 may be determined such that the above equation (1) or (2) is satisfied.

FIG. 11 is a diagram schematically showing another example of the guide structure 70 according to the embodiment. Similar to FIG. 3, FIG. 11 schematically shows a top view of the cold head 22. As shown in FIG. In this example, the guide structure 70 has a guide pin 72 as a guide portion provided on the sleeve side flange 52 and the outer peripheral surface 26a of the cold head side flange 26 as a guided portion. When the cold head side flange 26 moves in the axial direction of the cold head 22 with respect to the sleeve side flange 52 , the outer peripheral surface 26 a of the cold head side flange 26 is guided along the guide pin 72 . Therefore, the cold head side flange 26 is not provided with a guide hole into which the guide pin 72 is inserted. A clearance _dG is provided between the outer peripheral surface 26 a of the cold head side flange 26 and the guide pin 72 . The clearance _dG of the guide structure 70 may be determined such that any of the above equations (1), (2), or (3) is satisfied.

FIG. 12 is a diagram schematically showing another example of the guide structure 70 according to the embodiment. The guide structure 70 has an inner peripheral surface of the sleeve-side flange 52 as a guide portion, and a guide ring 80 provided on the inner cylindrical portion 44b of the transition flange 44 as a portion to be guided. Although the guide ring 80 is provided above the seal member 46 in this example, it may be provided below the seal member 46 . As the transition flange 44 moves in the axial direction of the cold head 22 relative to the sleeve-side flange 52 , the guide ring 80 is guided along the inner peripheral surface of the sleeve-side flange 52 . A clearance _dG is provided between the guide ring 80 and the inner peripheral surface of the sleeve-side flange 52 . The clearance _dG of the guide structure 70 may be determined such that any of the above equations (1), (2), or (3) is satisfied.

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 above embodiments, the cryogenic refrigerator 20 is a two-stage GM refrigerator, but the cryogenic refrigerator 20 may be a pulse tube refrigerator, a Stirling refrigerator, or some other type. may be a cryogenic refrigerator.

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.

Embodiments of the present invention can also be expressed as follows.

1. a coldhead containing sleeve comprising a sleeve-side flange, a single heat transfer stage, and a double heat transfer stage;
a cold head-side flange, a first-stage cooling stage, and a two-stage cooling stage cooled to a lower temperature than the first-stage cooling stage, wherein the first-stage cooling stage and the second-stage cooling stage respectively cool the cold head to the sleeve-side flange. a cold head that contacts or separates from the first-stage heat transfer stage and the second-stage heat transfer stage by movement of the head-side flange;
A guide structure for guiding movement of the cold head side flange with respect to the sleeve side flange, comprising: a guide section provided on the sleeve side flange; and a guided section provided on the cold head side flange and guided by the guide section. and a guide structure having a lateral clearance between the guide portion and the guided portion perpendicular to the direction of movement of the cold head flange,
The one-stage cooling stage and the two-stage cooling stage are separated from the one-stage heat transfer stage and the two-stage heat transfer stage, respectively. A cryogenic apparatus, wherein the clearance of the guide structure is defined to prevent contact between the cooling stage and the coldhead containing sleeve.

2. the coldhead containing sleeve comprises a two-stage sleeve body connecting the one-stage heat transfer stage to the two-stage heat transfer stage;
The guide structure is arranged such that the amount of lateral movement of the two-stage cooling stage due to the inclination of the guided portion with respect to the guide portion does not exceed the lateral distance between the two-stage cooling stage and the two-stage sleeve body. 2. The cryogenic apparatus of embodiment 1, wherein said clearance of is defined.

3. The clearance of the guide structure is such that the amount of downward movement of the edge portion of the first-stage cooling stage due to the inclination of the guided portion with respect to the guide portion does not exceed the lift height of the cold head side flange with respect to the sleeve side flange. 3. Cryogenic apparatus according to embodiment 1 or 2, characterized in that:

4. a coldhead containing sleeve comprising a sleeve-side flange, a single heat transfer stage, and a double heat transfer stage;
a cold head-side flange, a first-stage cooling stage, and a two-stage cooling stage cooled to a lower temperature than the first-stage cooling stage, wherein the first-stage cooling stage and the second-stage cooling stage respectively cool the cold head to the sleeve-side flange. a cold head that contacts or separates from the first-stage heat transfer stage and the second-stage heat transfer stage by movement of the head-side flange;
A guide structure for guiding movement of the cold head side flange with respect to the sleeve side flange, comprising: a guide section provided on the sleeve side flange; and a guided section provided on the cold head side flange and guided by the guide section. and a guide structure having a lateral clearance between the guide portion and the guided portion perpendicular to the direction of movement of the cold head flange,
The cold head comprises a two-stage cylinder connecting the first-stage cooling stage to the second-stage cooling stage, and a two-stage displacer housed in the two-stage cylinder movably relative to the two-stage cylinder,
The lateral gap between the two-stage cylinder and the two-stage displacer is under an unbalanced load acting on the cold head side flange when the two-stage cooling stage is pressed against the two-stage heat transfer stage. , wherein the clearance of the guide structure is defined so as not to exceed the allowable upper limit of .

5. The cold head side flange is fixed to a main flange and combined with the sleeve side flange to form an airtight region between the cold head receiving sleeve and the cold head, which is isolated from the surrounding environment. and a transition flange for
5. The cryogenic apparatus according to any one of Embodiments 1 to 4, wherein the guided portion is provided on the transition flange.

6. 6. Cryogenic apparatus according to embodiment 5, wherein the lateral clearance formed between the main flange and the guide portion is greater than the clearance of the guide structure.

7. The clearance of the guide structure has a first magnitude when the single cooling stage and the double cooling stage are in contact with the single heat transfer stage and the double heat transfer stage, respectively; the stage and the dual cooling stage have a second magnitude when spaced apart from the single heat transfer stage and the dual heat transfer stage, respectively, wherein the first magnitude is greater than the second magnitude; 7. A cryogenic apparatus according to any preceding embodiment, characterized in that it is small.

8. 8. The cryogenic apparatus according to any one of Embodiments 1 to 7, wherein the guide portion has a guide pin, and the guided portion has a guide hole into which the guide pin is inserted.

10 Cryogenic device 16 Ambient environment 18 Sealing area 22 Cold head 26 Cold head side flange 30 Single cooling stage 32 Double cylinder 34 Double cooling stage 38 Double displacer 42 Main flange 44 Transition Flange 50 Sleeve 52 Sleeve side flange 56 First stage heat transfer stage 60 Second stage heat transfer stage 70 Guide structure 72 Guide pin 74 Guide hole.

Claims (8)

a coldhead containing sleeve comprising a sleeve-side flange, a single heat transfer stage, and a double heat transfer stage;
a cold head-side flange, a first-stage cooling stage, and a two-stage cooling stage cooled to a lower temperature than the first-stage cooling stage, wherein the first-stage cooling stage and the second-stage cooling stage respectively cool the cold head to the sleeve-side flange. a cold head that contacts or separates from the first-stage heat transfer stage and the second-stage heat transfer stage by movement of the head-side flange;
A guide structure for guiding movement of the cold head side flange with respect to the sleeve side flange, comprising: a guide section provided on the sleeve side flange; and a guided section provided on the cold head side flange and guided by the guide section. and a guide structure having a lateral clearance between the guide portion and the guided portion perpendicular to the direction of movement of the cold head flange,
The one-stage cooling stage and the two-stage cooling stage are separated from the one-stage heat transfer stage and the two-stage heat transfer stage, respectively. A cryogenic apparatus, wherein the clearance of the guide structure is defined to prevent contact between the cooling stage and the coldhead containing sleeve. the coldhead containing sleeve comprises a two-stage sleeve body connecting the one-stage heat transfer stage to the two-stage heat transfer stage;
The guide structure is arranged such that the amount of lateral movement of the two-stage cooling stage due to the inclination of the guided portion with respect to the guide portion does not exceed the lateral distance between the two-stage cooling stage and the two-stage sleeve body. 2. The cryogenic apparatus of claim 1, wherein said clearance of is defined. The clearance of the guide structure is such that the amount of downward movement of the edge portion of the first-stage cooling stage due to the inclination of the guided portion with respect to the guide portion does not exceed the lift height of the cold head side flange with respect to the sleeve side flange. 3. Cryogenic apparatus according to claim 1 or 2, characterized in that it is defined. a coldhead containing sleeve comprising a sleeve-side flange, a single heat transfer stage, and a double heat transfer stage;
a cold head-side flange, a first-stage cooling stage, and a two-stage cooling stage cooled to a lower temperature than the first-stage cooling stage, wherein the first-stage cooling stage and the second-stage cooling stage respectively cool the cold head to the sleeve-side flange. a cold head that contacts or separates from the first-stage heat transfer stage and the second-stage heat transfer stage by movement of the head-side flange;
A guide structure for guiding movement of the cold head side flange with respect to the sleeve side flange, comprising: a guide section provided on the sleeve side flange; and a guided section provided on the cold head side flange and guided by the guide section. and a guide structure having a lateral clearance between the guide portion and the guided portion perpendicular to the direction of movement of the cold head flange,
The cold head comprises a two-stage cylinder connecting the first-stage cooling stage to the second-stage cooling stage, and a two-stage displacer housed in the two-stage cylinder movably relative to the two-stage cylinder,
The lateral gap between the two-stage cylinder and the two-stage displacer is under an unbalanced load acting on the cold head side flange when the two-stage cooling stage is pressed against the two-stage heat transfer stage. , wherein the clearance of the guide structure is defined so as not to exceed the allowable upper limit of . The cold head side flange is fixed to a main flange and combined with the sleeve side flange to form an airtight region between the cold head receiving sleeve and the cold head, which is isolated from the surrounding environment. and a transition flange for
5. The cryogenic apparatus according to claim 1, wherein the guided portion is provided on the transition flange. 6. The cryogenic apparatus of claim 5, wherein said lateral clearance formed between said main flange and said guide portion is greater than said clearance of said guide structure. The clearance of the guide structure has a first magnitude when the single cooling stage and the double cooling stage are in contact with the single heat transfer stage and the double heat transfer stage, respectively; the stage and the dual cooling stage have a second magnitude when spaced apart from the single heat transfer stage and the dual heat transfer stage, respectively, wherein the first magnitude is greater than the second magnitude; 7. Cryogenic apparatus according to any one of claims 1 to 6, characterized in that it is small. 8. The cryogenic apparatus according to claim 1, wherein the guide portion has a guide pin, and the guided portion has a guide hole into which the guide pin is inserted.

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