JP2000018744A - Pulse-pipe-type refrigerator and magnetic-shielding-type refrigeration system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the formation of a current loop caused by thermoelectromotive force being generated due to the material difference and temperature difference of each part. SOLUTION: An insulation cylinder 1 is provided at the inner periphery of a cold storage equipment pipe 11 of a pulse-pipe-type refrigerating machine 10 so that it surrounds a cold storage material 10. The through-hole of a refrigerant gas Gr is punched at both ends of the cold storage device pipe 11 and spacers 2a and 2b made of an insulation material are provided, thus reducing noise caused by the formation of a current loop and accurately measuring a weak physical quantity such as magnetism.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a pulse tube refrigerator and a magnetically shielded refrigeration system. More specifically, a pulse tube refrigerator that has been improved to suppress the formation of a current loop caused by a thermoelectromotive force generated by a material difference and a temperature difference in each part, and has been improved to be able to reduce the evaporation amount of a coolant. The present invention relates to a magnetic shield type refrigeration system. In particular,
SQUID (Superconducting QUantum Interference D
It is useful for cooling sensors such as evices (superconducting quantum interferometer) elements.

[0002]

2. Description of the Related Art FIG. 9 is a block diagram showing an example of a conventional pulse tube refrigerator. This pulse tube refrigerator 900
A regenerator tube 11 filled with a regenerator material 10, a pulse tube 12 having a cavity V therein, and a connection hole C connecting an upper end of the regenerator tube 10 and an upper end of the pulse tube 12 are formed. A connecting block 13, a flange 16 for positioning one end of a gas pipe 14 inside the pipe wall at the lower end of the regenerator tube 11, and an end of an orifice 15 inside the pipe wall for the lower end of the pulse tube 12, and the orifice 15. And a heat radiating case 17 having a buffer B connected to the other end.

[0003] The cold storage material 10 is, for example, a copper net (copper wire woven in a net shape). The material of the regenerator tube 11 and the pulse tube 12 is a metal material that is mechanically strong and has high heat insulation performance, for example, stainless steel. The material of the connection block 13 and the heat radiation case 17 is a metal material having high thermal conductivity, for example, copper.

The connecting block 13 is connected to the regenerator tube 1.
The refrigerant gas Gr is pulsed into and out of the pulse tube 1 and the pulse tube 12 to be cooled to an extremely low temperature (for example, about -200 ° C.). The refrigerant gas Gr is, for example, helium gas. A cooling target M is mounted on the upper surface of the connection block 13. The cooled object M is, for example,
This is a sensor unit having a built-in SQUID element for detecting a weak magnetic field.

From the viewpoint of preventing the leakage of the refrigerant gas Gr from the ends of the regenerator tube 11 and the pulse tube 12, a highly airtight seal portion α1 is provided between the regenerator tube 11 and the connection block 13. The gap between the regenerator tube 11 and the flange 16 is sealed by a highly airtight seal portion α2, and the pulse tube 12 and the connection block 1 are sealed.
3 is sealed by a highly airtight seal portion α3,
The space between the pulse tube 12 and the flange 16 is sealed by a highly airtight seal portion α4.

FIG. 10 shows a pulse tube refrigerator 900 of FIG.
It is a lineblock diagram of a refrigeration system including. This refrigeration system 910 is provided with a flange 16 of the pulse tube refrigerator 900.
And the heat radiation case 17 to the outside and other parts (the cold storage material 10, the cold storage tube 11, the pulse tube 12, the connecting block 1
3, a vacuum vessel 91 for containing the object to be cooled M) in a vacuum;
A compressor 92 having a high-pressure terminal H for sending the refrigerant gas Gr at a high pressure and a low-pressure terminal L for collecting the refrigerant gas Gr;
A high-pressure gas pipe 93 and a low-pressure gas pipe 94 derived from the high-pressure terminal H and the low-pressure terminal L, and a gas pipe 95 connected to the gas pipe 14 of the pulse-tube refrigerator 900.
And a motor drive having an internal valve connected to the compressor 92 via an electric wiring 96 and alternately connecting the high-pressure gas pipe 93 and the low-pressure gas pipe 94 to the gas pipe 95 at a constant period of, for example, 1 to 20 Hz. The switching valve 97 is provided.

During the period in which the motor drive switching valve 97 switches the internal valve to the high pressure gas pipe 93, that is, the high pressure terminal H, the regenerator tube 11 and the connection hole C of the connection block 13 (FIG. 9). Then, the refrigerant gas Gr flows into the pulse tube 12 in a pulsed manner. At this time, the refrigerant gas Gr at the lower end (buffer B side) of the pulse tube 12
Are compressed to generate heat, and the heat is radiated from the heat radiation case 17. On the other hand, while the motor switching valve 65 is switching the internal valve to the low-pressure gas pipe 94, that is, the low-pressure terminal L, the connection hole C of the connection block 13
The refrigerant gas Gr in the pulse tube 12 flows out in a pulse manner via the regenerator tube 11. At this time, since the refrigerant gas Gr flows out while adiabatically expanding at the upper end (the regenerator tube 11 side) of the pulse tube 12, the vicinity of the upper end becomes cold, and the cool air is absorbed by the cold storage material 10, and The temperature of the connection block 14 decreases. Therefore, by continuously switching the internal valve of the motor drive switching valve 97, the temperature of the connection block 13 can be reduced to an extremely low temperature, and the object to be cooled M can be cooled.

FIG. 11 is a block diagram showing an example of a conventional magnetically shielded refrigeration system. This magnetically shielded refrigeration system 920 includes a magnetically shielded device 51 having an inner space magnetically shielded from the outside, a container-like outer wall Wo, and an inner wall Wi.
A heat insulating device 53 in which a coolant 52 is held in a space surrounded by the inner wall Wi, the outer wall Wo and the inner wall W
i, a heat shield plate 54 provided in the vacuum layer between the inner wall W, a sensor 55 disposed at the bottom of the inner wall Wi, and the inner wall W
and a heat insulator 56 provided on the top of i. The coolant 52 is, for example, liquid helium. The sensor 55 is a magnetic detection element such as a SQUID element. The low-temperature gas g vaporized by the coolant 52 is discharged through a gap between the inner wall Wi of the heat insulating device 53 and the heat insulator 56. At this time, the inner wall Wi and the heat shielding plate 54 receive heat from the gas g and are cooled.

[0009]

In the conventional pulse tube refrigerator 900, as shown in FIG. 12, a thermoelectromotive force is generated due to a material difference and a temperature difference between the regenerator material 10 and the regenerator tube 11. A current loop i-1 transmitted through the cold storage material 10 and the cold storage tube 11 is easily formed by the thermoelectromotive force.
Similarly, the regenerator tube 11, the connecting block 13, and the pulse tube 1
2, a current loop i-2 due to the thermoelectromotive force is easily formed. However, such a current loop i-1,
Since i-2 is a factor that generates the magnetic noise N, there is a problem that an error in measuring a weak magnetic field increases.

In the conventional magnetically shielded refrigeration system 920, since the coolant 52 is liable to evaporate due to the invasion of heat from the outside, the coolant 52 needs to be replenished frequently, and the operating cost increases. There is a problem.

Accordingly, a first object of the present invention is to provide a pulse tube refrigerator capable of suppressing the formation of a current loop due to a thermoelectromotive force generated by a material difference or a temperature difference in each part. A second object of the present invention is to provide a magnetically shielded refrigeration system that can reduce the amount of evaporation of a coolant.

[0012]

According to a first aspect of the present invention, there is provided a regenerator having a regenerator tube filled with a regenerator material and a pulse tube having a cavity therein substantially parallel to each other. A flange is attached to one end of the tube and one end of the pulse tube, and the other end of the regenerator tube and the other end of the pulse tube are connected by a connection block. A pulse tube refrigerator of a type that cools the connection block by pulsing refrigerant gas into and out of the regenerator tube, wherein an insulating cylinder is provided on the inner periphery of the regenerator tube so as to surround the regenerator material. A pulse tube refrigerator is provided. In the pulse tube refrigerator according to the first aspect, the insulating tube is provided so as to surround the regenerator material on the inner periphery of the regenerator tube, so that the regenerator material and the regenerator tube can be electrically insulated. The formation of a current loop due to the generation of a thermoelectromotive force during the period can be suppressed. As a result, generation of a noise magnetic field can be suppressed, and errors in measuring a weak magnetic field can be reduced.

According to a second aspect of the present invention, a regenerator tube filled with a regenerator material and a pulse tube having a cavity therein are arranged substantially in parallel, and one end of the regenerator tube and the regenerator tube are arranged in parallel. A flange is attached to one end of the pulse tube, and the other end of the regenerator tube and the other end of the pulse tube are connected by a connecting tube made of a conductive material. A pulse tube refrigerator of a type that cools a low-temperature generating portion that covers a part or the entirety of the connection pipe by pulsating refrigerant gas into and out of the connection pipe, and in the middle of the connection pipe,
Provided is a pulse tube refrigerator including an insulating member for interrupting a current transmitted through the connection tube. In the pulse tube refrigerator according to the second aspect, since the insulating member is provided in the middle of the connecting tube, the regenerator tube and the pulse tube can be electrically insulated. It is possible to suppress the formation of a current loop due to generation of a thermoelectromotive force in between. As a result, generation of a noise magnetic field can be suppressed, and errors in measuring a weak magnetic field can be reduced.

According to a third aspect, the present invention provides a metal tube for functioning as a regenerator tube, a pulse tube coaxially provided on the inner periphery of the metal tube, and a pulse tube having the metal tube as an outer wall. A cold storage material filled in a cylindrical space having a pipe as an inner wall,
An insulating cylinder provided on the inner periphery of the metal tube so as to surround the cold storage material, a flange attached to one end of the metal tube and one end of the pulse tube, and the other end of the metal tube; A connection block for connecting the other end of the pulse tube to the other end of the pulse tube, wherein the connection block is cooled by pulsating refrigerant gas into and out of the cylindrical space and the pulse tube to cool the connection block. Provide a container. In the pulse tube refrigerator according to the third aspect, since the insulating tube is provided on the inner periphery of the metal tube so as to surround the cold storage material, the cold storage material and the metal tube can be electrically insulated. The formation of a current loop due to the generation of a thermoelectromotive force during the period can be suppressed. As a result, generation of a noise magnetic field can be suppressed, and errors in measuring a weak magnetic field can be reduced. In addition, since the pulse tube is provided coaxially on the inner periphery of the metal tube for functioning as a regenerator tube, leakage of the refrigerant gas can be prevented only by sealing two places corresponding to both ends of the coaxial structure. Can be simplified. Further, by providing the metal tube and the pulse tube coaxially, mechanical strength can be increased, and the wall thickness of each tube can be reduced. Furthermore, the size can be reduced as compared with a case where a regenerator tube and a pulse tube are separately provided.

According to a fourth aspect, the present invention provides the pulse tube refrigerator according to any one of the first to third aspects, wherein at least one of the regenerator tube and the pulse tube is provided. A pulse tube refrigerator having a spacer provided on one end side and made of an insulating material and provided with a passage hole for the refrigerant gas. In the pulse tube refrigerator according to the fourth aspect, a spacer made of an insulating material is provided on at least one end side of the regenerator tube or the pulse tube. The noise can be further increased, and the generation of a noise magnetic field due to the formation of the current loop can be further suppressed.

According to a fifth aspect of the present invention, there is provided a magnetic shielding device having an inner space magnetically shielded from the outside, and a container-shaped outer wall and an inner wall provided in the inner space and surrounded by the inner wall. A heat insulating device capable of holding a coolant in the space defined, a cooled object to be cooled by the coolant, and at least one heat shield plate interposed in a layer between the outer wall and the inner wall. A magnetically shielded refrigeration system comprising:
A compressor for thermally coupling a low-temperature generating portion of the pulse tube refrigerator to the heat shield plate and sending refrigerant gas to the pulse tube refrigerator; and a compressor for the pulse tube refrigerator and the compressor. A magnetically-shielded refrigeration system, characterized in that a switching valve for switching a valve so as to reciprocate refrigerant gas between pulses is installed outside the magnetically shielded device. In the magnetically shielded refrigeration system according to the fifth aspect, the heat shield plate of the heat insulating device installed inside the magnetic shield device is cooled by the pulse tube refrigerator, so that the heat insulating performance of the heat insulating device is improved and the coolant is cooled. The consumption can be reduced and the operating costs can be saved. In addition, since a compressor and a switching valve, which are likely to be noise sources, are installed outside the magnetic shielding device, the intrusion of noise into the magnetic shielding device can be suppressed.
It is possible to obtain a measurement environment suitable for precise measurement of a weak measurement target (such as magnetism).

According to a sixth aspect of the present invention, there is provided a magnetic shielding apparatus having an inner space magnetically shielded from the outside, and a container-shaped outer wall and an inner wall provided in the inner space and surrounded by the inner wall. A heat insulating device capable of holding a coolant in the space defined, a cooled object to be cooled by the coolant, and at least one heat shield plate interposed in a layer between the outer wall and the inner wall. A magnetically shielded refrigeration system comprising:
A heat insulator is provided on the upper portion of the inner wall, and a heat transfer plate thermally connected to the heat shield plate is buried or fixed in the heat insulator, and the heat transfer plate heats the low-temperature generating section of the pulse tube refrigerator. A compressor that sends refrigerant gas to the pulse tube refrigerator and a switching valve that switches a valve so that the refrigerant gas reciprocates in a pulsed manner between the pulse tube refrigerator and the compressor. A magnetic shield type refrigeration system is provided outside the magnetic shield device. In the magnetically shielded refrigeration system according to the sixth aspect, a heat insulator is provided above the heat insulator installed inside the magnetic shield, and the heat insulator is thermally coupled to the heat shield plate of the heat insulator. Since the heat plate is buried (or fixed) and the heat transfer plate is cooled by a pulse tube refrigerator, the temperature of the gas layer in which the coolant has been vaporized should be reduced by the gap between the heat transfer plate and the heat shield plate. Can be done. Thereby, the heat insulating performance of the heat insulating device can be improved, the consumption of the coolant can be reduced, and the operating cost can be reduced. In addition, since a compressor and a switching valve, which are likely to be noise sources, are installed outside the magnetic shielding device, the intrusion of noise into the magnetic shielding device can be suppressed, making it suitable for precision measurement of weak measurement targets (such as magnetism). Measurement environment can be obtained.

In a seventh aspect, the present invention provides the magnetically shielded refrigeration system according to the fifth aspect or the sixth aspect, wherein the pulse tube refrigerator comprises the fourth aspect from the first aspect. A magnetically shielded refrigeration system characterized by being a pulse tube refrigerator of any one of the aspects. In the magnetically shielded refrigeration system according to the seventh aspect, the pulse tube refrigerator according to any one of the first to fourth aspects is embedded in a heat shield plate or a heat insulator of a heat insulating device. Since the fixed heat transfer plate is cooled, the same operation as the operation of the pulse tube refrigerator according to any one of the first to fourth aspects is obtained from the first aspect, and the heat insulating performance of the heat insulating device is improved. Coolant consumption can be reduced and operating costs can be saved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited by this.

First Embodiment FIG. 1 is a configuration diagram showing a pulse tube refrigerator according to a first embodiment of the present invention. This pulse tube refrigerator 100
Comprises a regenerator tube 11 filled with a regenerator material 10, a pulse tube 12 having a cavity V therein,
An insulating cylinder 1 provided on the inner periphery of the cold storage material 10 so as to surround the cold storage material 10, an upper end of the cold storage tube 11 and the pulse tube 12;
A connection block 13 formed with a connection hole C for connecting the upper end of the regenerator tube 11 and one end of a gas pipe 14 to which the refrigerant gas Gr is supplied inside the lower wall of the regenerator tube 11 are located. Orifice 15 inside tube wall at lower end
A flange 16 for positioning one end of the orifice 1
Radiation case 17 having buffer B connected to the other end of 5
Are provided. The refrigerant gas Gr is, for example, helium gas. At the lower end of the regenerator tube 11, a through hole for the refrigerant gas Gr is provided, and a spacer 2a made of an insulating material is provided. Further, at the upper end of the regenerator tube 11, a through hole for the refrigerant gas Gr is formed, and a spacer 2b made of an insulating material is provided. The material of the spacers 2a, 2b is, for example, glass fiber reinforced plastic (FRP; Fiber glass Reinforc).
ed Plastic). A shunt 3 made of a conductive material is provided between the regenerator tube 11 and the pulse tube 12.
1, 3-2,... Are provided. The shunt 3-
The material of 1,3-2,... Is, for example, copper.

The cold storage material 10 is, for example, a copper net (copper wire woven in a net shape). The material of the regenerator tube 11 and the pulse tube 12 is a non-magnetic metal material that is mechanically strong and has high heat insulation performance, for example, stainless steel, or desirably titanium or a titanium alloy. The material of the insulating cylinder 1 is, for example, an insulating plastic film such as polyester or polyimide. The material of the connection block 13 and the heat radiation case 17 is a metal material having high thermal conductivity, for example, copper.

The connecting block 13 includes the regenerator tube 1.
The refrigerant gas Gr is pulsed into and out of the pulse tube 1 and the pulse tube 12 to be cooled to an extremely low temperature (for example, about -200 ° C.). The refrigerant gas Gr is, for example, helium gas. A cooling target M is mounted on the upper surface of the connection block 13. The cooled object M is, for example,
This is a sensor unit having a built-in SQUID element for detecting a weak magnetic field.

From the viewpoint of preventing leakage of the refrigerant gas Gr from the ends of the regenerator tube 11 and the pulse tube 12, a highly airtight seal portion α1 is provided between the regenerator tube 11 and the connection block 13. The gap between the regenerator tube 11 and the flange 16 is sealed by a highly airtight seal portion α2, and the pulse tube 12 and the connection block 1 are sealed.
3 is sealed by a highly airtight seal portion α3,
The space between the pulse tube 12 and the flange 16 is sealed by a highly airtight seal portion α4. These sealing methods are welding or brazing.

FIG. 2 is a configuration diagram of a refrigeration system including the pulse tube refrigerator 100 of FIG. This refrigeration system 1
Reference numeral 10 denotes a flange 16 and a heat radiating case 17 of the pulse tube refrigerator 100 which are exposed to the outside and other portions (the cold storage material 10, the cold storage tube 11, the insulating tube 1, the pulse tube 12, the connecting block 13, the cooling target). M) in a vacuum, a compressor 92 having a high-pressure terminal H for sending the refrigerant gas Gr at a high pressure and a low-pressure terminal L for collecting the refrigerant gas Gr, the high-pressure terminal H and the low-pressure terminal L And a high-pressure gas pipe 93 and a low-pressure gas pipe 94, a gas pipe 95 connected to the gas pipe 14 of the pulse tube refrigerator 100, and an electric wiring 96 connected to the compressor 92. A motor drive switching valve 97 having an internal valve for alternately connecting the gas pipe 93 and the low-pressure gas pipe 94 with the gas pipe 95 at a constant cycle is provided.

According to the pulse tube refrigerator 100 described above,
Since the insulating cylinder 1 is provided on the inner periphery of the regenerator tube 11 so as to surround the regenerator material 10 and the spacers 2a and 2b made of insulating material are provided at both ends of the regenerator tube 11, the regenerator material 10 and the regenerator tube 11 are provided. Can be electrically insulated from each other, and the formation of a current loop due to generation of a thermoelectromotive force therebetween can be suppressed. The regenerator tube 11 and the pulse tube 12
, A large number of shunts 3-1, 3-2,.
A current loop of a large current is not formed between the first, the connecting block 13 and the pulse tube 12. As a result, generation of a noise magnetic field can be suppressed, and errors in measuring a weak magnetic field can be reduced.

Second Embodiment FIG. 3 is a block diagram showing a pulse tube refrigerator according to a second embodiment of the present invention. This pulse tube refrigerator 200
Comprises a regenerator tube 11 filled with a regenerator material 10, a pulse tube 12 having a cavity V therein,
Tube 2 connecting the upper end of the pulse tube 12 and the upper end of the pulse tube 12
1, an insulating joint 22 interposed between the connecting pipes 21 and made of an insulating material, a low-temperature generating part 23 covering the connecting pipe 21, and a refrigerant at a lower end of the regenerator pipe 11 inside the pipe wall. A heat radiation case 17 having a flange 16 for positioning one end of a gas pipe 14 to which gas Gr is supplied and an end of an orifice 15 inside a tube wall at a lower end of the pulse tube 12, and a buffer B connected to the other end of the orifice 15 Are provided. The material of the insulating joint 22 is, for example, an insulating plastic such as polyester or polyimide or a ceramic body. According to the pulse tube refrigerator 200 described above, since the insulating joint 22 is provided in the middle of the connecting tube 21, the regenerator tube 11 and the pulse tube 12 can be electrically insulated, and between the two. The formation of a current loop due to the generation of thermoelectromotive force can be suppressed. As a result, generation of a noise magnetic field can be suppressed, and errors in measuring a weak magnetic field can be reduced.

Third Embodiment FIG. 4 is a configuration diagram showing a pulse tube refrigerator according to a third embodiment of the present invention. This pulse tube refrigerator 300
Is a metal tube 31 functioning as a regenerator tube, and a pulse tube 32 coaxially provided on the inner periphery of the metal tube 31.
A cold storage material 33 filled in a cylindrical space having the metal tube 31 as an outer wall and the pulse tube 32 as an inner wall; and an insulating tube provided on the inner periphery of the metal tube 31 so as to surround the cold storage material 33. 41, a connection block 34 having a concave portion connecting the upper end of the metal tube 31 and the upper end of the pulse tube 32, and a gas pipe 14 at the lower end of the cylindrical space inside the tube wall.
And one end of the orifice 15 inside the tube wall at the lower end of the pulse tube 32
6 and a buffer B connected to the other end of the orifice 15
And a heat radiating case 17 having the following.
The material of the insulating cylinder 41 is, for example, a glass fiber reinforced epoxy resin. The material of the metal tube 31 is, for example, phosphor bronze or a titanium alloy. The material of the pulse tube 32 is a glass fiber reinforced resin or a ceramic body. At the lower end of the cylindrical space, there is provided a spacer 45a formed with a through hole for the refrigerant gas Gr and made of an insulating material. At the upper end of the pulse tube 32, a through hole for the refrigerant gas Gr is formed, and a spacer 45b made of an insulating material is provided.
Is provided. The metal tube 31 and the pulse tube 32
From the viewpoint of preventing leakage of the refrigerant gas Gr from the end of
The space between the metal tube 31 and the pulse tube 32 and the connection block 34 is sealed by a highly airtight seal portion α11, and the space between the metal tube 31 and the pulse tube 32 and the flange 16 is highly airtight. Sealed by the seal portion α12. According to the above-described pulse tube refrigerator 300, the insulating cylinder 41 is provided on the inner periphery of the metal tube 31 so as to surround the cold storage material 33, and the spacers 45 a and 45 b made of an insulating material are provided on both ends of the cold storage material 33. So cold storage material 3
3 and the metal tube 31 can be electrically insulated, and the formation of a current loop due to generation of a thermoelectromotive force therebetween can be suppressed. As a result, generation of a noise magnetic field can be suppressed, and errors in measuring a weak magnetic field can be reduced. In addition, the leakage of the refrigerant gas Gr from both ends of the metal tube 31 functioning as a cold storage tube and the pulse tube 32 can be prevented by merely providing the two seal portions α11 and α12, so that the structure can be simplified and the manufacturing cost can be reduced. Can be reduced. Further, by providing the metal tube 31 and the pulse tube 32 coaxially, mechanical strength can be increased,
The wall thickness of each tube can be reduced. Furthermore, the size can be reduced as compared with the case where the regenerator tube and the pulse tube are separately provided.

Fourth Embodiment FIG. 5 is a configuration diagram showing a magnetically shielded refrigeration system according to a fourth embodiment of the present invention. The magnetically shielded refrigeration system 400 includes a magnetically shielded device 51 having an inner space magnetically shielded from the outside, a container-shaped outer wall Wo and an inner wall Wi, and cooling in a space surrounded by the inner wall Wi. Agent 5
2, a heat shield plate 54 provided in a vacuum layer between the outer wall Wo and the inner wall Wi, and a sensor 55 such as a SQUID element provided at the bottom of the inner wall Wi. The pulse tube refrigerator 900 (FIG. 9) in which the low-temperature generating portion, that is, the connecting block 13 is brought into contact with the heat shielding plate 54, and the heat radiation case 17 is extended out of the heat insulating device 53.
), And a heat insulator 56 provided above the inner wall Wi.
A compressor 92 for sending a refrigerant gas Gr such as helium gas to the pulse tube refrigerator 900; and a refrigerant gas Gr between the pulse tube refrigerator 900 and the compressor 92.
And a motor drive switching valve 97 for switching the valve so that the pulse is reciprocated. The coolant 52 is, for example, liquid helium. The material of the wall surface of the heat insulating device 53 is, for example, glass fiber reinforced plastic (FRP). The material of the heat insulator 56 is, for example, porous polystyrene. The material of the heat shielding plate 54 is, for example, copper or aluminum, an insulated copper wire or a copper net, or a material obtained by integrating them with a resin sheet. The compressor 92 and the motor drive switching valve 97
Is installed outside the magnetic shielding device 51. The low-temperature gas g vaporized by the coolant 52 is discharged through a gap between the inner wall Wi of the heat insulating device 53 and the heat insulator 56. At this time, the inner wall Wi and the heat shielding plate 5
4 is cooled by the heat taken by the gas g.
In addition, the gas pipe 95 connecting the pulse tube refrigerator 900 and the motor drive switching valve 97 is made as short as possible from the viewpoint of preventing intrusion of noise into the magnetic shield device 51 and is provided with a magnetic shield device. It is preferable that the inside and the outside of 51 are electrically insulated. In addition, gas piping 95
Is made of a conductive material, it is preferable to make the gas pipe 95 the same potential as the wall surface of the magnetic shielding device 51. According to the magnetic shield type refrigeration system 400 described above, since the heat shield plate 54 is cooled by bringing the connection block 13 of the pulse tube refrigerator 900 into contact with the heat shield plate 54, the heat insulation performance is improved and the coolant 52 Reduce consumption,
Operation costs can be reduced. Further, the compressor 92 which is likely to be a noise source and the motor drive switching valve 9
Since the device 7 is installed outside the magnetic shielding device 51, it is possible to suppress noise from entering the magnetic shielding device 51 and accurately measure weak magnetism.

Fifth Embodiment FIG. 6 is a configuration diagram showing a magnetically shielded refrigeration system according to a fifth embodiment of the present invention. This magnetically shielded refrigeration system 500 has a magnetically shielded device 51 having an inner space magnetically shielded from the outside, a container-shaped outer wall Wo and an inner wall Wi, and cooling in a space surrounded by the inner wall Wi. Agent 5
2, a heat shield plate 54 provided in a vacuum layer between the outer wall Wo and the inner wall Wi, and a sensor 55 such as a SQUID element provided at the bottom of the inner wall Wi. A heat insulator 56 buried (or fixed) with a heat transfer plate 61 provided above the inner wall Wi and having both end faces facing the heat shield plate 54;
Tube-type refrigerator 900 (see FIG. 9) in which a low-temperature generating unit, that is, a connecting block 13 is brought into contact with the compressor, a compressor 92 that sends refrigerant gas Gr such as helium gas to the pulse-tube refrigerator 900, and the pulse tube. A motor drive switching valve 97 that switches a valve so as to reciprocate the refrigerant gas Gr between the refrigerator 92 and the compressor 92 in a pulsed manner is provided. The material of the heat transfer plate 61 is
For example, copper. The compressor 92 and the motor drive switching valve 97 are installed outside the magnetic shielding device 51. Since both end surfaces of the heat transfer plate 61 are thermally connected to the heat shielding plate 54 via a layer of the gas g in which the coolant 52 is vaporized, the gas g is connected to the heat transfer plate 61 with the heat transfer plate 61. It is cooled in the gap with the heat shielding plate 54. According to the above magnetically shielded refrigeration system 500, the gas g in which the coolant 52 is vaporized
Since the heat insulation performance can be improved by further lowering the temperature of the fuel cell, the consumption of the coolant 52 can be reduced, and the operating cost can be reduced. In addition, the compressor 92 which is likely to be a noise source
In addition, since the motor drive switching valve 97 is provided outside the magnetic shielding device 51, it is possible to suppress the intrusion of noise into the magnetic shielding device 51 and accurately measure weak magnetism.

Sixth Embodiment FIG. 7 is a configuration diagram showing a magnetically shielded refrigeration system according to a sixth embodiment of the present invention. The magnetic shield refrigeration system 600 cools the heat shield plate 54 by bringing the connection block 13 of the pulse tube refrigerator 100 (see FIG. 1) according to the first embodiment into contact with the heat shield plate 54. It is a configuration to do. According to the magnetic shielding type refrigeration system 600 described above, the connection block 13 of the pulse tube refrigerator 100 is brought into contact with the heat shielding plate 54 to cool the heat shielding plate 54, so that the consumption of the coolant 52 is reduced. , Operation costs can be reduced. Further, since the pulse tube refrigerator 100 according to the first embodiment is used, the regenerator tube (FIG. 1) is used.
11) and the cold storage material filled therein (1 in FIG. 1)
0) can be electrically isolated from each other, and the generation of magnetic noise due to the formation of a current loop can be reduced.

Seventh Embodiment FIG. 8 is a configuration diagram showing a magnetically shielded refrigeration system according to a seventh embodiment of the present invention. In this magnetically shielded refrigeration system 700, the connection block 13 of the pulse tube refrigerator 100 (see FIG. 1) according to the first embodiment is brought into contact with the heat transfer plate 61 embedded in the heat insulator 56, The heat transfer plate 61 is cooled. According to the magnetic shielding type refrigeration system 700 described above, the coolant 52 evaporates the gas g.
Since the heat insulation performance can be improved by further lowering the temperature of the fuel cell, the consumption of the coolant 52 can be reduced, and the operating cost can be reduced. In addition, since the pulse tube refrigerator 100 according to the first embodiment is used, a regenerator tube (11 in FIG. 1) is used.
And the cold storage material (10 in FIG. 1) filled therein can be electrically insulated, and the generation of magnetic noise due to the formation of a current loop can be reduced.

[0032]

According to the pulse tube refrigerator of the present invention, the regenerator tube and the regenerator material are insulated by the insulating cylinder provided on the inner periphery of the regenerator tube, or the regenerator tube and the pulse tube are connected. Since insulation is provided by the insulating member provided in the tube, noise due to the formation of a current loop can be reduced, and a weak physical quantity (such as magnetism) can be accurately measured. Further, according to the magnetic shield type refrigeration system of the present invention, the heat shield plate of the heat insulating device in the magnetic shield device is cooled by the pulse tube type refrigerator, or the heat transfer plate embedded or fixed in the heat insulator. Since the plate is cooled by the pulse tube refrigerator to lower the temperature of the gas layer between the heat transfer plate and the heat shield plate, the heat insulation performance can be improved, and the consumption of the coolant can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a pulse tube refrigerator according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a refrigeration system including the pulse tube refrigerator of FIG. 1;

FIG. 3 is a configuration diagram illustrating a pulse tube refrigerator according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a pulse tube refrigerator according to a third embodiment of the present invention.

FIG. 5 is a configuration diagram of a magnetically shielded refrigeration system according to a fourth embodiment of the present invention.

FIG. 6 is a configuration diagram of a magnetically shielded refrigeration system according to a fifth embodiment of the present invention.

FIG. 7 is a configuration diagram of a magnetically shielded refrigeration system according to a sixth embodiment of the present invention.

FIG. 8 is a configuration diagram of a magnetically shielded refrigeration system according to a seventh embodiment of the present invention.

FIG. 9 is a configuration diagram showing an example of a conventional pulse tube refrigerator.

FIG. 10 is a configuration diagram illustrating a refrigeration system including the pulse tube refrigerator of FIG. 9;

FIG. 11 is a configuration diagram showing a conventional magnetically shielded refrigeration system.

FIG. 12 is an explanatory diagram of a current loop formed in each part of the pulse tube refrigerator of FIG. 9;

[Explanation of symbols]

100, 200, 300 Pulse tube refrigerator 400, 500, 600, 700 Magnetically shielded refrigeration system 1, 41 Insulation cylinder 2a, 2b, 45a, 45b Spacer 3-1, 3-2,3-3,3-4 Shunt 10,33 Cold storage material 11 Cold storage tube 12,32 Pulse tube 13 Connecting block 22 Insulating joint 31 Metal tube 51 Magnetic shield device 52 Coolant 53 Heat insulation device 54 Heat shield plate 55 Sensor 56 Heat insulator 61 Heat transfer plate 92 Compressor 97 Motor drive switching valve

Claims (7)

[Claims] 1. A regenerator tube filled with a regenerator material,
A pulse tube having a cavity therein is arranged substantially in parallel, a flange is attached to one end of the regenerator tube and one end of the pulse tube, and the other end of the regenerator tube and the other end of the pulse tube A pulse tube refrigerator of a type that cools the connection block by pulsating refrigerant gas into and out of the regenerator tube and the pulse tube. A pulse tube refrigerator having an insulating cylinder provided on the inner periphery so as to surround the cold storage material. 2. A regenerator tube filled with a regenerator material,
A pulse tube having a cavity therein is arranged substantially in parallel, a flange is attached to one end of the regenerator tube and one end of the pulse tube, and the other end of the regenerator tube and the other end of the pulse tube Is connected by a connecting pipe made of a conductive material, and a low-temperature generating portion that covers a part or the whole of the connecting pipe by cooling / cooling the refrigerant gas into and out of the regenerator pipe and the pulse pipe is cooled. A pulse tube refrigerator of the type, characterized in that an insulating member for interrupting a current flowing through the connection tube is provided in the middle of the connection tube. 3. A metal tube for functioning as a regenerator tube, a pulse tube provided coaxially on the inner periphery of the metal tube, and a cylindrical space having the metal tube as an outer wall and the pulse tube as an inner wall. Cold storage material filled in, an insulating cylinder provided on the inner periphery of the metal tube so as to surround the cold storage material, a flange attached to one end of the metal tube and one end of the pulse tube, A connecting block for connecting the other end of the metal tube and the other end of the pulse tube, and cooling the connection block by pulsing refrigerant gas into and out of the cylindrical space and the pulse tube. A pulse tube refrigerator. 4. The pulse tube refrigerator according to claim 1, wherein at least one of one or both of the regenerator tube and the pulse tube is made of an insulating material. A pulse tube refrigerator having a spacer provided with a passage hole for the refrigerant gas. 5. A magnetic shielding device having an inner space magnetically shielded from the outside world, and a coolant installed in the inner space and having a container-like outer wall and an inner wall and surrounded by the inner wall, and containing a coolant therein. A magnetically shielded refrigeration system including a heat insulating device that can be held, a cooled object to be cooled by the coolant, and at least one heat shield plate interposed in a layer between the outer wall and the inner wall. A compressor for thermally coupling a low-temperature generating section of a pulse tube refrigerator to the heat shield plate, and for sending a refrigerant gas to the pulse tube refrigerator; and the pulse tube refrigerator. A magnetically shielded refrigeration system, wherein a switching valve for switching a valve to reciprocate the refrigerant gas between the compressors in a pulsed manner is provided outside the magnetically shielded device. 6. A magnetic shielding device having an internal space magnetically shielded from the outside world, and a coolant installed in the internal space and having a container-like outer wall and an inner wall and surrounded by the inner wall, A magnetically shielded refrigeration system including a heat insulating device that can be held, a cooled object to be cooled by the coolant, and at least one heat shield plate interposed in a layer between the outer wall and the inner wall. A heat insulator is provided above the inner wall, and a heat transfer plate thermally connected to the heat shield plate is embedded or fixed in the heat insulator, and a low temperature of a pulse tube refrigerator is provided on the heat transfer plate. A compressor that thermally couples the generator and sends refrigerant gas to the pulse tube refrigerator, and a valve that causes the refrigerant gas to reciprocate in a pulsed manner between the pulse tube refrigerator and the compressor. A switching valve for switching is installed outside the magnetic shielding device Magnetic shielding type refrigeration system, characterized in that the. 7. The magnetically shielded refrigeration system according to claim 5, wherein the pulse tube type refrigerator includes:
A magnetically shielded refrigeration system, comprising the pulse tube refrigerator according to any one of claims 1 to 4.