JP2010016025A - Superconducting device - Google Patents

Abstract

A superconducting coil is firmly supported in a heat insulating container of a superconducting device to prevent occurrence of shaking.
In a superconducting apparatus that houses a coil case containing a superconducting coil in a heat insulating container, a support material having heat insulation properties at opposite positions on both the upper and lower sides, the left and right sides, and the front and rear sides of the box-shaped heat insulating container. The inner ends of these supporting members are fixed to the coil case, and the coil case is sandwiched between the supporting members in the vertical direction, the horizontal direction, and the front-rear direction, and the inner surface of the heat insulating container The coil case is supported and fixed with a gap.
[Selection] Figure 1

Description

  The present invention relates to a superconducting device, and in particular, when the superconducting device is mounted on a vibrating body or a moving body, the heat-conducting container and the superconducting coil are arranged so as not to cause the superconducting coil housed in the heat-insulating container (cryostat) to shake or bend. The superconducting coil is fixed.

The superconducting coil needs to be cooled to a superconducting temperature of about 77 K (Kelvin) even when a high-temperature superconducting material is used, and is usually housed in a heat insulating container called a cryostat or a cryocooler having a heat insulating structure. .
The cooling of the superconducting coil in the heat insulation container can be done by filling the heat insulation container with a refrigerant (liquid nitrogen, liquid neon, liquid hydrogen, liquid helium, etc.) or by inserting the cold head of the refrigerator into the heat insulation container. It may be cooled by a cold heat transfer type.

As described above, since it is necessary to keep the superconducting coil cooled to the superconducting temperature in the heat insulating container, the superconducting coil is not fixed to the wall surface of the heat insulating container and is often supported by being suspended using a support material. .
For example, in Japanese Patent Application Laid-Open No. 2003-178912 shown in FIG. 6, the superconducting coil 101 is suspended from the lid 102 by the support member 104 inside the container 100 surrounded by the double wall of the outer wall 100a and the inner wall 100b. It is immersed in liquid nitrogen 103 that is accommodated and filled inside the container.

  When the cooling container is installed on a stationary fixed base, it is not necessary to consider external vibrations. As described above, the cooling container is suspended from the upper wall using a minimum of high heat insulation material. There is no problem even if it is lowered.

  However, when a superconducting device is used in a nuclear magnetic resonance imaging apparatus (MRI) and the MRI is mounted on a vehicle for traveling examination, a superconducting device may be mounted on a moving body or a vibrating body such as a train or a ship. is there. As described above, in an environment subject to intense vibration from the outside, it is necessary to firmly support the superconducting coil in the heat insulating container, and as shown in FIG. 5, the superconducting coil is suspended from the lid via the support material. As a result, the superconducting coil is likely to sway or bend in the heat insulating container. In that case, there is a problem that the superconducting coil is damaged, deteriorated or deformed, and accordingly, quenching is likely to occur.

  Furthermore, the superconducting coil is often housed in a heat insulating container built in a coil case for shielding. In this case, when the coil case is cooled from the normal temperature to the superconducting temperature, heat shrinkage occurs. Even if the support material is fixed to the coil case at normal temperature, the coil case is between the tip of the support material and the mounting portion of the coil case. A gap is generated, and the coil case cannot be integrated with the heat insulating container. If it will be in this state, a coil case will vibrate easily and the superconducting coil in this coil case will deteriorate easily.

JP 2003-178912 A

  This invention is made | formed in view of the said problem, and makes it a subject to fix a superconducting coil firmly to a heat insulation container so that a superconducting coil may not shake and bend within a heat insulation container.

In order to solve the above-mentioned problem, the present invention is a superconducting device for accommodating a coil case containing a superconducting coil in a heat insulating container,
A heat-insulating support material is supported so as to be able to be pushed in and attached to opposite positions on both the upper and lower sides, the left and right sides, and the front and rear sides of the box-shaped heat insulation container, and the inner ends of these support materials are fixed to the coil case. The superconducting device is characterized in that the coil case is sandwiched between the support material in the up-down direction, the left-right direction, and the front-rear direction, and the coil case is supported and fixed with a clearance from the inner surface of the heat insulating container. is doing.

In the superconducting device of the present invention, a coil case containing a superconducting coil is supported in a heat insulating container (cryostat) by suspending from above, and sandwiched by support materials from the left, right, up, down, and front and back directions. It is firmly fixed. Therefore, it is possible to prevent quenching from occurring without causing the coil case to sway or bend in the heat insulating container, and not to cause damage, deterioration, or deformation to the superconducting coil in the coil case.
Even if the superconducting device is mounted on a vibrating body or a moving body and the heat insulating container vibrates, it is possible to reliably prevent the superconducting coil in the coil case from shaking in the heat insulating container.

  The heat insulating container preferably has a high heat insulating performance as a double wall composed of an outer wall and an inner wall with a vacuum layer interposed therebetween. In this heat insulation container comprising a double wall, the inside of the inner wall is evacuated and a coil case containing a superconducting coil is accommodated in the evacuated interior.

The heat insulating container is composed of an outer wall and an inner wall sandwiching a vacuum layer,
The support material is a pipe or rod;
The inner end of the support bar is pushed into an insertion hole opened on the outer surface of the coil case, while the outer end of the support bar whose position changes between normal temperature and cooling is sandwiched between the outer wall and the inner wall. Located in a vacuum layer,
A support material pushing device provided with a bellows (intervening tray) pressed against the outer end of the support material and a push rod to be pushed in from the outside of the outer wall is attached to the outer wall, and the support rod is inserted through the bellows by the push rod. It is preferable that the heat insulating container and the coil case are integrated by eliminating the gap between the inner end of the support bar and the tip of the insertion hole.

In the present invention, as described above, the coil case is sandwiched from the left-right direction, the up-down direction, and the front-rear direction by the support member protruding from the heat-insulating container, so that the coil case is not shaken in the heat-insulating container. Although it can be firmly fixed, if the coil case is loosened by the support material, the coil case may be shaken by vibration even if it is fixed via the support material as described above. It becomes.
The assembly for supporting the coil case in the heat insulating container via the support material is performed at room temperature before the operation of the superconducting device. Therefore, even if the tip of the support member is brought into contact with the insertion hole of the coil case in the normal temperature state and connected, if the inside of the coil case is lowered to the superconducting temperature during operation of the superconducting device, thermal contraction occurs in the coil case. A gap will be generated between the insertion hole of the coil case and the tip of the support material.
In the present invention, after the assembly at room temperature, when the shrinkage occurs due to the heat shrinkage in the coil case cooled at the superconducting temperature, the support material is coiled through the bellows by being pushed into the push rod from the outside of the heat insulating container. The gap is eliminated by pushing into the insertion hole of the case to compensate for heat shrinkage, and the support material is integrated with the coil case.

  The support material is preferably formed of a glass fiber reinforced resin or a Kepler fiber reinforced resin having high insulating properties, low thermal conductivity, and high strength.

  When the superconducting coil is a horizontally long racetrack type, a plurality of the support members attached to the coil case from the heat insulating container are arranged at intervals in the top, bottom, left and right, and front and rear, and the outer walls on both the front and rear sides that are horizontally long It is preferable to attach a stay for holding the gap therebetween.

The outer wall and inner wall of the heat insulating container are formed of a metal such as stainless steel or aluminum or FRP.
When the superconducting device is mounted on a moving body, weight reduction is required, and therefore the outer wall is preferably made of lightweight aluminum. When the outer wall is formed of thin aluminum, if the inner surface side is a vacuum layer and atmospheric pressure is applied to the outer surface, the outer wall is likely to be deformed. In particular, the front and rear outer walls having a large area in the lateral length are easily deformed. However, when the stay for maintaining the distance is provided to reinforce the outer wall, the outer wall can be formed of thin aluminum, and as a result, the heat insulating container can be reduced in weight and size. Therefore, when a superconducting device is mounted on a moving body, the load on the superconducting device can be reduced.

Further, when the outer wall is formed of a metal material such as aluminum or aluminum alloy, natural cooling or cooling with cooling water can be easily performed.
On the other hand, when the inner wall is formed of FRP, even if an alternating current is passed through the superconducting coil, an induced current does not flow through the heat insulating container to generate heat, and the heat loss of the entire superconducting device is reduced and the cooling efficiency can be increased.
Further, the superconducting coil is housed in a vacuum case inside a coil case made of a shield case filled with resin.

  In the superconducting device of the present invention, a refrigerator is fixed to the upper surface or the lower surface of the outer wall of the heat insulating container, and a cold head connected to the refrigerator protrudes from the inside of the inner wall or the inside of the coil case. It is preferable to cool to superconducting temperature by heat conduction cooling brought into contact with a heat transfer material protruding from the inner core of the superconducting coil.

That is, instead of cooling the superconducting coil by immersing the superconducting coil in liquid nitrogen filled in the heat insulating container, the cold head of the refrigerator is brought into contact with the superconducting coil for cooling.
This is because liquid nitrogen can only exist as a liquid at temperatures above the freezing point of 64K (Kelvin), so the critical current flowing through the high-temperature superconductor at 68K to 77K is low, the maximum magnetic field is 1T or less, and a high magnetic field is generated. There is a problem that cannot be done.
On the other hand, when the superconducting coil is cooled by the direct cooling heat transfer method using the refrigerator, the superconducting coil can be cooled to 10K to 50K, and the critical current can be increased without lengthening the superconducting wire.

Furthermore, when the heat insulating container of the superconducting device is mounted on a moving body or a vibrating body, it is preferable to place the heat insulating container via a vibration-proof mount rubber.
As described above, when the mount rubber is interposed, the mount rubber becomes a shock absorber and absorbs the vibration, thereby attenuating the vibration of the heat insulating container itself.

  In the superconducting device of the present invention having the above-described configuration, the coil case containing the superconducting coil is sandwiched between the left and right sides, the top and bottom sides, and the front and back sides, respectively, with a heat-insulating support material and fixed in the heat insulating container. It is possible to prevent the coil case from being shaken or bent in the heat insulating container. As a result, the superconducting coil inside the coil case can be prevented from being damaged, deteriorated, or deformed, and the occurrence of quenching can be suppressed based on the damage.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
An embodiment of the superconducting device of the present invention will be described with reference to FIGS.
The superconducting device 1 is mounted on a train or ship which is a moving body and a vibrating body, and a heat insulating container (cryostat) 2 is fixed on a base 3 with a mautra bar 10 interposed.

The heat insulating container 2 has a double-walled sealed box shape in which an outer wall 4 and an inner wall 5 are provided with a vacuum layer 6 interposed therebetween.
The outer wall 4 is formed from a thin aluminum alloy plate, and the inner wall 5 is formed from a copper plate. The vacuum layer 6 sandwiched between the outer wall 4 and the inner wall 5 serves as a heat insulating space. The vacuum layer 6 accommodates multiple radiation films (not shown) in which a reflective material is attached to a resin film.
The inside 7 of the inner wall 5 is also evacuated, and the superconducting coil 8 is housed in a coil case 9 made of a shield case made of metal such as aluminum. The coil case 9 is filled with a resin 11 and a superconducting coil 8 is molded in the resin 11 and is built therein. The superconducting coil 8 is a racetrack coil formed of a bismuth or yttrium high temperature superconducting wire.

A two-stage refrigerator 12 is mounted on the upper surface of the outer wall 4, a second stage 12 b of the refrigerator 12 is projected from the inner wall 5, and a cold head (copper cooling path) 12 c is provided at the tip. On the other hand, a copper cooling plate 40 is disposed between the superconducting coils 8 stacked in parallel inside the coil case 9, and protrusions 40 a are provided at three locations at intervals on the upper ends of the copper cooling plates 40. The upper surface of the portion 40a is connected by a silver square bar 41, and the silver square bar 41 is connected to the cold bed 12c. Thereby, the superconducting coil 8 is cooled to the superconducting temperature by the direct cooling heat transfer method.
Further, the lead wire (not shown) of the superconducting coil 8 is also drawn from the upper surface of the coil case 9 through the heat insulating container 2 and connected to an AC power source (not shown).

  The coil case 9 is supported by a support member 20 made of a heat insulating material attached to the heat insulating container 2 in the vacuumed inner portion 7 of the inner wall 5 of the heat insulating container 2, and a gap is formed between the inner wall 5 and the inner surface. Contained without contact.

Specifically, as shown in FIG. 1, two support members 20 are attached to the left side with an interval in the vertical direction, and the two support members 20 are similarly attached to the left side and opposite positions on the right side. Further, the left and right outer surfaces of the coil case 9 are sandwiched by a total of four support members 20.
Two support members 20 are attached to the upper side with a space in the left-right direction, and the two support members 20 are similarly attached to the lower side so as to face the upper side. The upper and lower outer surfaces of the case 9 are clamped.
Further, as shown in FIG. 2, the front and rear surfaces having the maximum area are each six, and a total of twelve support members 20 are attached to sandwich the front and rear surfaces of the coil case 9. Specifically, the upper and lower left and right corners of the front and rear surfaces, the lower left and right corners, and the central part surrounded by the inner periphery of the superconducting coil are provided at the top and bottom, and six support members 20 are attached in total. .
In this way, the coil case 9 is sandwiched and fixed inside the heat insulating container 2 by using a total of 20 support members 20.

The support material 20 is a round bar formed of glass fiber reinforced resin (GERP) or Kepler FRP having high insulation and strength.
Each support member 20 is fixed to a bellows 23 of a support member pushing device 22 in which an outer end 20a is fixed to the outer surface of the outer wall 4 as shown in FIG. The bellows-equipped device 22 fixes the case 24 to the outer wall 4, the outer end of the coil spring 25 is fixed to the lid 24 a of the case 24, the bellows 23 is fixed to the inner end of the coil spring 25, and the bellows 23 is fixed by the coil spring 25. Is biased toward the inner wall 5 side (inward).
The outer end 20a of the support member 20 is fixed to the inner surface of the bellows 23, while the screw rod 26 is fixed to the inner end of the bellows 23, and the outer end of the screw rod 26 projects outward from the lid 24a. Yes. By screwing a nut 27 into the screw rod 26, the screw rod 26 is moved inward to deform the bellows 23 inward, and the support member 20 is moved by the deformation of the bellows 23 to move the inner end. The fixed portion 20b is moved to the coil case 9 side.

  The coil case 9 is provided with an insertion hole 30 into which the fixing portion 20b on the inner end side of the support member 20 is inserted. As shown in FIG. 4A, the end surface 20c of the fixing portion 20b of the support member 20 is fixed to the bottom surface 30a of the insertion hole 30 by pressure contact.

  Further, as shown in FIG. 2, four spacing holding stays 33 are attached between the front and rear outer walls 4 in the central region surrounded by the inner periphery of the superconducting coil 8, and the inward bending of the outer wall 4 is performed. Support to prevent. The interval holding stay 33 is made of a vacuum double heat insulating vip and is thermally insulated.

  The coil case 9 is assembled into the heat insulating container 2 at normal temperature, and the end surface 20c of the fixing portion 20b of the support member 20 is pressed against the bottom surface 30a of the insertion hole 30 of the coil case 9 at normal temperature. Thus, the coil case 9 can be fixed in the heat insulating container 2 so as not to move by sandwiching the left and right surfaces, the upper and lower surfaces, and the front and rear surfaces of the coil case 9 with the support material 20.

When the superconducting coil 8 is cooled to an extremely low temperature (20 Kelvin) by the refrigerator 12, the coil case 9 is thermally contracted, and the bottom surface 30a of the insertion hole 30 of the coil case 9 is shown in FIG. And a gap S between the fixed portion end surface 20c of the support member 20 is generated. Therefore, looseness occurs at the end 20a of the support material 20 on the normal temperature side.
At that time, the nut 27 is screwed into the screw rod 26 protruding outward, the screw rod 26 is moved inward, the support member 20 is pushed into the insertion hole 30 through the bellows 23, and is inserted into the bottom surface 30a. The gap S is eliminated by pressure-contacting the fixed portion end surface 20c.
Thus, the coil case 9 can be fixed and integrated with the support member 20 without backlash.

  In the superconducting device having the above-described configuration, the coil case 9 can be integrated and fixed so as not to move inside the heat insulating container 2, so that the coil case 9 can be prevented from being shaken or deformed by vibration inside the heat insulating container 2. . As a result, it is possible to prevent the superconducting coil 8 in the coil case 9 from being damaged, deteriorated, or deformed, and to suppress the occurrence of quenching in the superconducting coil 8.

  Further, since the outer wall 4 of the heat insulating container 2 is vacuum on the inner surface side and external atmospheric pressure is applied to the outer surface side, the front and rear outer walls 4 having a large area are easily bent inward. Since the outer wall is supported from the inside, deformation can be prevented. Thus, since the outer wall 4 is reinforced, the thickness of the outer wall 4 can be reduced and the weight can be reduced.

This invention is not limited to the said embodiment, The support material pushing-in apparatus attached to the said heat insulation container is good also as a structure shown in FIG.
In the support material pushing device 22, a bolt hole 23 x is provided in a peripheral portion of an intervening tray (bellows) 23 whose inner surface side is a pressing contact surface with the support rod 20, and the bolt hole 23 x is provided on the shaft portion 50 a of the bolt 50. The front end of the bolt shaft portion is fixed to a lid portion 24 a fixed to the outer wall 4. A gap C is provided between the head 50 b of the bolt 50 and the interposition tray 23. A push rod 53 is fixed to the outer surface of the intervening tray 23, and the push rod 53 penetrates the lid portion 24a and protrudes outward.
In the above configuration, when the room temperature is set, the support member 20 is fixed in a state in which the push bar 53 on the outer surface side of the interposition tray 23 and the support member 20 on the inner surface side are pressed against each other. When the coil case is cooled and contracts, and a gap is generated between the support member 20 and the interposition tray 23, the interposition tray 23 is pushed by the push rod 53, and the interposition tray 23 is advanced by the dimension of the gap C, so that the bolt The interposition tray 23 is abutted against the head 50b. By the advancement of the intervening tray 23, the gap between the intervening tray 23 and the support member 20 is eliminated, and the support member 20 is pushed and supported by the intervening tray 23.

Further, the inner end of the support member and the coil case may be fixed by screw fixing instead of a method of inserting the tip fixing portion of the support member into the insertion hole provided in the coil case.
Further, the superconducting coil may be cooled by a direct cooling heat transfer system using a cold head, and the superconducting coil may be cooled by filling liquid nitrogen into the coil case. Furthermore, although the superconducting device is mounted on a ship in the above-described embodiment, it can also be suitably used when mounted on a moving body such as an automobile or a train.
That is, the present invention is not limited to the above-described embodiments, and includes embodiments that do not depart from the gist of the present invention.

It is a whole lineblock diagram showing the superconducting device of the embodiment of the present invention. It is the II-II sectional view taken on the line of FIG. It is an enlarged view which shows the attachment state by the outer wall side of a support material. (A) (B) is an enlarged view which shows the state which fixes a support material to the insertion hole of a coil case. It is drawing which shows the modification of the attachment structure of a support material and an outer wall. It is drawing which shows a prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Superconducting device 2 Thermal insulation container 4 Outer wall 5 Inner wall 6 Vacuum layer 8 Superconducting coil 9 Coil case 12 Refrigerator 20 Support material 20b Fixed part 20c End surface 22 Support material pushing-in device 23 Bellows (intervening dish)
24 Case 25 Coil spring 26 Screw rod 27 Nut 30 Insertion hole

Claims (6)

A superconducting device that houses a coil case containing a superconducting coil in a heat insulating container,
A heat-insulating support material is supported so as to be able to be pushed in and attached to opposite positions on both the upper and lower sides, the left and right sides, and the front and rear sides of the box-shaped heat insulation container, and the inner ends of these support materials are fixed to the coil case. The superconducting device is characterized in that the coil case is sandwiched between the support members in the up-down direction, the left-right direction, and the front-rear direction, and the coil case is supported and fixed with a clearance from the inner surface of the heat insulating container. The heat insulating container is composed of an outer wall and an inner wall sandwiching a vacuum layer,
The support material is a pipe or rod;
The inner end of the support bar is pushed into an insertion hole opened on the outer surface of the coil case, while the outer end of the support bar whose position changes between normal temperature and cooling is sandwiched between the outer wall and the inner wall. Located in a vacuum layer,
A support material pushing device provided with a bellows (intervening tray) pressed against the outer end of the support material and a push rod to be pushed in from the outside of the outer wall is attached to the outer wall, and the support rod is inserted through the bellows by the push rod. The superconducting device according to claim 1, wherein the heat insulating container and the coil case are integrated by pushing inwardly and eliminating a gap between the inner end of the support bar and the tip of the insertion hole.   The superconducting device according to claim 1, wherein the support material is made of glass fiber reinforced resin or Kepler fiber reinforced resin.   When the superconducting coil is a horizontally long racetrack type, a plurality of the support members attached to the coil case from the heat insulating container are arranged at intervals in the top, bottom, left and right, and front and rear, and the outer walls on both the front and rear sides that are horizontally long The superconducting device according to any one of claims 1 to 3, further comprising a stay for holding a gap therebetween.   A moving body on which the superconducting device according to any one of claims 1 to 4 is mounted.   A vibrating body on which the superconducting device according to any one of claims 1 to 4 is mounted.

Images