JP3484926B2 - Superconducting magnet device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting magnet device formed by axially connecting superconducting magnets provided with a cooling container for accommodating the superconducting coil so that the superconducting coil has a superconducting destruction. The present invention relates to a superconducting magnet device that can be excited and demagnetized stably without generating noise.

[0002]

2. Description of the Related Art As a typical example of a conventional superconducting magnet device,
Cylindrical magnetic resonance imaging device (MR
There is a superconducting magnet device for I). This generates a highly uniform and strong magnetic field at the center of a cylindrical device. On the other hand, in a superconducting magnet device for a magnetic resonance imaging apparatus, an open-type superconducting magnet device that reduces a patient's feeling of oppression, as is known, for example, in JP-A-62-026052 and JP-A-04-007808. Has been applied. In such a device, for example, as shown in the perspective view of FIG. 5, it is common to connect two superconducting magnets 1 by a plurality of connecting pipes 2.

In recent years, for example, Japanese Patent Laid-Open No. 58-0745.
As described in Japanese Patent Application Laid-Open No. 94, Japanese Patent Application Laid-Open No. 59-203793, Japanese Patent Application Laid-Open No. 60-036391, and the like,
MCZ (Magnetic Field)
The application of the s-applied Czochrski) method is expanding. When a lateral magnetic field is applied to a large pulling furnace, two superconducting magnets are installed and the magnets are connected by a plurality of connecting pipe devices, as in the superconducting magnet device of FIG. In general, a pulling furnace is placed between two superconducting magnets.

The structure of the superconducting magnet device as described above will be described in more detail with reference to FIGS. 5 is a perspective view of the superconducting magnet device, FIG. 6 is a cross-sectional view, and FIG. 7 is an enlarged cross-sectional view showing a part A of the cross-section in FIG. 6 in an enlarged manner. In these figures, the superconducting magnet 1
Is configured as follows. The vacuum vessel 11 is formed by welding a stainless steel plate into an annular shape having a rectangular cross section. The cooling container 12 has an inner cylinder 12a and side plates 12b on both sides, and is formed in an annular shape having a rectangular cross section. A portion of the side plate 12b on the inner cylinder 12a side is used as a flange portion 12c. A part of the cooling container 12 is also used as an annular winding frame portion 12d having a U-shaped cross section, which is composed of the inner cylinder 12a and the flange portion 12c.

The superconducting coil 13 is wound around the winding frame portion 12d in an annular shape having a rectangular cross section, has a side surface portion 13a, and is housed in the cooling container 12. A coil positioning member 14 is provided on the other side surface of the superconducting coil 13 for supporting the superconducting coil 13 in the Z-axis direction and for coil positioning during winding. The coil positioning member 14 is previously fixed to the inner cylinder 12a of the cooling container before the winding work. The superconducting coil 13 is wound at room temperature so that there is no gap in the winding frame portion 12d formed by the coil positioning member 14 and the one flange portion 12c on the right side. However, in the state where the superconducting coil 13 is cooled to the superconducting state, the contraction rate of the superconducting conductor is larger than that of stainless steel, so that the superconducting coil 13 contracts to a greater extent, so that the coil positioning member 14 and the one flange portion 12c are There is a small gap between them.

Between the vacuum container 11 and the cooling container 12,
A two-layer heat shield 15 and a super insulation (not shown) are provided around the periphery. Although not shown, the cooling container 12 and the heat shield 15 are supported by the vacuum container 11 via a heat insulating support material. In addition, as shown in FIG. 6, liquid helium 16 is filled in the vacuum container 11 up to the liquid level B. The superconducting magnet 1 configured as described above is connected in the Z-axis direction in FIG. 6 by the two connecting pipe devices 2.

The connecting pipe device 2 includes a vacuum container connecting pipe 21 for connecting the vacuum containers 11 of the two superconducting magnets 1 and a cooling container connecting pipe 2 for connecting the cooling containers 12 in a fixed state.
2 and a two-layer connecting member 2 for connecting the heat shields 15 to each other.
It is composed of 3 layers and 4 layers. The cooling container connecting pipe 22 is
As shown in FIG. 7, it is formed as a hollow pipe, and serves as a flow path for liquid helium or gas helium and as a passage for leads that electrically connect a plurality of superconducting coils 13. In addition, in FIG. 7, the two-layer connecting member 2
3 is omitted in the figure.

Further, as shown in FIG. 5, a service port 3 for injecting liquid helium and exhausting helium gas, a shield refrigerator 4 for cooling the heat shield layer, and the like are installed. The service port 3 also serves as an exciting lead takeout port of the superconducting coil 13.

When the superconducting magnet 1 shown in FIG. 6 is excited, each superconducting coil 13 receives an electromagnetic force in the direction of arrow C. This electromagnetic force is transmitted to the flange portion 12c of the cooling container 12 and receives a reaction force from the cooling container connecting pipe 22. Therefore, the cooling device 12 is generally provided with the connecting portion between the side plate 12b and the cooling container connecting pipe 22 as a fixed point. It deforms as shown by the broken line in FIG. When this deformation occurs, the side surface portion 13a (see FIG. 7) of the superconducting coil 13 is the flange portion 12 of the cooling container 12.
It receives local concentrated stress from c. In addition, the superconducting coil 13
In the state in which the superconducting coil is cooled to the superconducting state, there is a slight gap in the Z-axis direction between the superconducting coil 13 and the one flange portion 12c or the coil positioning member 14 as described above. Deforms in the Z-axis direction and collides with the deformed flange portion 12c.

For this reason, there is a possibility of local collapse and superconducting breakdown (hereinafter referred to as quench). In particular,
In the case of local collapse, quenching is repeated with each excitation. In addition, when the superconducting coil 13 is deformed, the diameter of the superconducting coil is much larger than that of its cross section, and the superconducting coil 13 has considerable flexibility, so that each portion in the circumferential direction of the superconducting coil undulates in the axial direction. Deformed into a flange 12
Since it collides with c, the local concentrated stress is further increased. For this reason, the frequency of quenching upon excitation increases.

[0011]

As described above, in a superconducting magnet device having a structure in which a plurality of superconducting magnets 1 are installed and these are connected by a connecting pipe device 2, because of mutual electromagnetic force between the superconducting magnets 1. The cooling container 12 was deformed, and the device became unstable with respect to the quench. In order to prevent this, it is conceivable to increase the plate thickness of the cooling container 12 to increase the strength. However, there is a problem that cost and weight increase.

Further, for example, the superconducting magnets 1 are firmly fixed to a foundation by a supporting device so as to withstand the electromagnetic force of the superconducting magnets, and a flexible pipe is inserted in a part of the cooling container connecting pipe 22. The cooling container connecting pipe 22 may be configured so as not to be directly affected by the reaction force, but it has a drawback that the cost is increased and the device becomes bulky. An object of the present invention is to solve the above problems and to obtain a superconducting magnet device having a lightweight and compact structure and capable of improving quenching resistance.

[0013]

A superconducting magnet device according to the present invention has a rectangular cross section, is formed in an annular shape by a plate-like member, and the inner peripheral side is a winding frame portion around which a superconducting coil is wound. Two superconducting magnets each having a cooling container supported and housed via a heat insulating member and arranged to face each other in the axial direction of the superconducting coil, a connecting pipe device having a cooling container connecting pipe for fixedly connecting the cooling containers to each other, Further, the cooling container is provided with an unbalanced load suppressing member that suppresses an unbalanced load from being applied to the superconducting coil by the electromagnetic force generated when the superconducting coil is excited.

Further, the winding frame portion is formed in a U-shaped cross section by the cylindrical portion and the pair of flange portions, and the unbalanced load suppressing member is connected to the cooling container connecting pipe of the cooling container with one plate thickness of the flange portion. The thick flange is made thicker than the plate thickness of the portion, and the electromagnetic force of the superconducting coil is received by the thick flange.

Further, the eccentric load suppressing member is an eccentric load suppressing flange provided inside one of the flange portions, and the eccentric load suppressing flange receives the electromagnetic force of the superconducting coil.

Further, the unbalanced load suppressing member is a cylindrical reinforcing member arranged in the cooling container so as to be coaxial with the cylindrical portion and on the outer peripheral side of the superconducting coil.

[0017]

DETAILED DESCRIPTION OF THE INVENTION

Embodiment 1. FIG. 1 shows an embodiment of the present invention and is a cross-sectional view of a main part corresponding to FIG. 7 showing a conventional one. In FIG. 1, the annular electromagnet 100 is configured as follows. The vacuum container 11 is formed by welding a non-magnetic stainless steel plate into an annular shape having a rectangular cross section.

The cooling container 112 has an inner cylinder 12a which is a cylindrical portion on the inner peripheral side, a left side plate 12b in FIG. 1, a thick flange 112c thicker than the side plate 12b and provided on the right side, and this thick flange. It has a right side plate 12b welded to 112c, and is formed into an annular shape having a rectangular cross section by welding a nonmagnetic stainless steel plate. The thick flange 112c has an outer diameter slightly larger than the diameter of the superconducting coil 13, contacts the superconducting coil 13, and receives an electromagnetic force. The other side plate 12b (on the left side in FIG. 1) is used as a flange portion 12c at a portion near the inner cylinder 12a. The inner cylinder 12a, the flange portion 12c, and the thick flange portion 112c form an annular winding frame portion 112d having a U-shaped cross section. That is, a part of the cooling container 112 is also used as the winding frame portion 112d. The inner cylinder 12 that constitutes the cooling container 12
The a and the side plates 12b are made of non-magnetic thin stainless steel plate.

The superconducting coil 13 is wound around the winding frame 112d in an annular shape having a rectangular cross section, has a side surface 13a, and is housed in the cooling container 112. In addition, the superconducting coil 13
A coil positioning member 14 is installed on the other side surface of the superconducting coil 13 for supporting the superconducting coil 13 in the Z-axis direction and for positioning the coil during winding. Coil positioning member 14
Is fixed to the inner cylinder 12a of the cooling container 112 in advance before starting the winding. The superconducting coil 13 is wound around the winding frame portion 112d formed by the coil positioning member 14 and the thick flange portion 112c at room temperature without any gap in the axial direction. However, when cooled to the superconducting state, the shrinkage rate of the superconducting conductor of the superconducting coil 13 is larger than that of the stainless steel bobbin portion 112d, so that the superconducting coil 13 has a coil positioning member 14 and a thick flange portion 112c. And has a minute axial gap.

Between the vacuum container 11 and the cooling container 112, two layers of heat shield and super insulation (not shown) are provided in the periphery, but they are not shown. Although not shown, the cooling container 112 and the heat shield are supported by the vacuum container 11 via a heat insulating support material. Liquid helium is placed in the vacuum container 11 as in the conventional one shown in FIG. The superconducting magnet 100 configured as described above is connected in the Z-axis direction in FIG. 1 by the two connecting pipe devices 2 (see also FIG. 6).

The connecting pipe device 2 includes two superconducting magnets 100.
Vacuum container connecting pipe 21 for connecting the vacuum containers 11 of the above, a cooling container connecting pipe 22 for connecting the cooling containers 12 in a fixed state, and a two-layer connecting member for connecting heat shields (not shown) (see FIG. 6). (See the connecting member 23) and four layers. The cooling container connecting pipe 22 has a thick flange portion 1
The side plates 12b, which are thinner than 12c, are fixedly connected to each other. The cooling container connecting pipe 22 is a hollow pipe as shown in FIG. 1, and serves as a flow path for liquid helium or gas helium and as a lead passage for electrically connecting a plurality of superconducting coils 13. Playing a role.

A liquid helium injection, a service port for helium gas exhaust, a shield refrigerator for cooling the heat shield layer, and the like, which are the same as the conventional ones, are installed, but they are not shown. By adopting such a structure, even if the cooling container 112 is deformed as shown by the broken line due to the electromagnetic force during excitation, the thick flange portion 112c is hardly deformed, so that the corners of the superconducting coil 13, especially the side surface portion 13a are not deformed. Local concentrated stress acting on the part is reduced. In addition, the superconducting coil 13, the coil positioning member 14, and the thick flange portion 1
Even if the superconducting coil 13 is deformed so as to undulate in the axial direction due to a small axial gap between the superconducting coil 13 and 12c,
Since the thick flange portion 112c is hardly deformed, the local concentrated stress received by the superconducting coil 13 at this time is relaxed.

Embodiment 2. FIG. 2 is a cross-sectional view of essential parts showing another embodiment of the present invention. In the figure, inside the cooling container 212 of the superconducting magnet 200, as shown in the drawing,
The inner flange 220 is fixed to the flange portion 12c (side plate 12b) with a predetermined gap in the Z-axis direction. The inner flange 220 receives the electromagnetic force of the superconducting coil 13. Since other configurations are similar to those of the first embodiment shown in FIG. 1, the corresponding components are designated by the same reference numerals and the description thereof will be omitted. The inner flange 220 is
Since it is provided separately from the flange portion 12c and apart from it, it is not directly affected by the deformation of the cooling container 212. The inner flange 220 is the superconducting coil 1.
Since it abuts on one side surface portion 13a of No. 3, even if the cooling container 212 is deformed as shown by the broken line by the electromagnetic force at the time of excitation, local concentrated stress acting on the superconducting coil 13, particularly on the corner portion of the side surface portion 13a is reduced. be able to.

Even if the superconducting coil 13 and the coil positioning member 14 and the inner flange 220 have a small axial gap and the superconducting coil 13 is deformed so as to undulate in the axial direction, Sometimes superconducting coil 13
The ability to relieve local concentrated stress on
It is similar to that shown in the embodiment of FIG. Note that the cooling container 212 shown in FIG. 2 is different from that shown in FIG.
The superconducting coil 13 is wound between the inner cylinder 12a and the coil positioning members 14 and the inner flanges 220 on both sides, and then the side plates 12b on both sides are welded to the inner cylinder 12a.
Since d can be formed, there is an advantage that the work of winding the superconducting coil 13 becomes easy.

Embodiment 3. 3 and 4 are a fragmentary cross-sectional view and a perspective view of a reinforcing member showing still another embodiment of the present invention. In these figures, the superconducting magnet 30
Reference numeral 0 denotes a reinforcing member 320 provided inside the cooling container 12 of the conventional superconducting electromagnet shown in FIG. Reinforcement member 320
4, has a plurality of plate-shaped reinforcing plates 322 radially welded at predetermined intervals on the outer periphery of a cylindrical member 321 which is a cylindrical reinforcing member.
The cylindrical member 321 and the reinforcing plate 322 are both made of non-magnetic stainless steel plate. The cylindrical member 321 and the reinforcing plate 322 are fixed to the side plate 12b of the cooling container by welding.

By thus forming the reinforcing member 320 in a cylindrical shape, uniform force can be received from the superconducting coil 13. Further, the reinforcing member 320 that supports the side plate 12b that receives the reaction force from the cooling container connecting pipe 22 is welded to the side plate 12b to be integrated with the side plate 12b to form a strong beam. Therefore, the cooling container 12 is prevented from being largely deformed by the electromagnetic force transmitted from the superconducting coil 13.

In this embodiment, the reinforcing member 32
By providing 0, it is not necessary to increase the plate thickness of the flange portion 12c, so that there is an advantage that the axial length of the entire device can be prevented from increasing.

Fourth Embodiment By combining the above-mentioned respective embodiments, with a lightweight and compact structure while comprehensively suppressing an increase in size, weight or cost,
Moreover, it is possible to obtain a superconducting magnet device with improved quenching resistance. Further, in each of the above embodiments,
Although the case where two superconducting magnets are connected by two connecting devices is shown, the same effect can be obtained even when two or more superconducting magnets are connected by two or more connecting devices.

Furthermore, in order to reduce the leakage magnetic field to the outside of the superconducting magnet, the superconducting magnet may be surrounded by a shield made of a ferromagnetic material. In this case, the value and direction of the electromagnetic force at the time of excitation change due to the influence of the ferromagnetic material, but the same effect is obtained. Further, the vacuum container is not limited to an annular one having a rectangular cross section, and may have another shape, for example, a cylindrical shape.

[0030]

Since the present invention is configured as described above, it has the following effects.

A thick-walled flange is formed by making one plate thickness of the flange portion of the winding frame thicker than the plate thickness of the portion connected to the cooling container connecting pipe of the cooling container, and the electromagnetic force of the superconducting coil is generated by this thick-walled flange. Since the cooling container receives the electromagnetic force of the superconducting coil and deforms with the connecting part with the cooling container connecting pipe as a fixed point, the thick flange does not deform so much that the superconducting coil is biased. The load is suppressed.
Since it is possible to suppress the unbalanced load of the superconducting coil with a thick flange without forming the entire cooling container with a thick wall, it is possible to reduce an increase in the weight of the device.

Further, an inner flap is provided on one inner side of the flange portion.
Since the inner flange is designed to receive the electromagnetic force of the superconducting coil by this inner flange, even if the cooling container receives the electromagnetic force of the superconducting coil and deforms with the connecting part with the cooling container connecting pipe as a fixed point, the inner flange Deformation of the superconducting coil is suppressed, and the superconducting coil is prevented from receiving an unbalanced load. Further, since the inner flange is provided separately from one of the flange portions, the superconducting coil can be wound without using the pair of flange portions, and the work of winding the superconducting coil is facilitated.

[0033] Then, both ends are fixed to the side plate of the cooling vessel at the outer side of the superconducting coil and the circular cylindrical portion coaxially
Since the cylindrical reinforcing member is arranged in the cooling container as described above, the cooling container is reinforced by the cylindrical reinforcing member, and the deformation due to the electromagnetic force is reduced, so that the superconducting coil is prevented from receiving an unbalanced load. Further, since the deformation of the cooling container is suppressed by the cylindrical reinforcing member without forming the entire cooling container to be thick, it is possible to reduce the increase in the weight of the device.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an essential part showing another embodiment of the present invention.

FIG. 3 is a cross-sectional view of an essential part showing another embodiment of the present invention.

FIG. 4 is a perspective view of the reinforcing member of FIG.

FIG. 5 is a perspective view showing a conventional superconducting magnet device.

FIG. 6 is a sectional view showing the conventional superconducting magnet of FIG.

FIG. 7 is an enlarged cross-sectional view showing a part A of the cross-section in FIG. 6 in an enlarged manner.

[Explanation of symbols]

11: vacuum container, 12, 112, 212: cooling container, 1
2c: flange part, 112c: thick flange part, 12
d, 112d: reel part, 13: superconducting coil, 13a:
Side part, 2: Connection pipe device, 22: Cooling container connection pipe, 22
0: inner flange, 320: reinforcing member, 321: cylindrical member.

Front page continuation (72) Inventor Kazuki Moritsu 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. (56) Reference JP-A-1-205507 (JP, A) JP-A-2-237101 ( JP, A) JP-A-8-102416 (JP, A) JP-A-6-244026 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01F 6/00-6/06 A61B 5/05 H01L 39/02-39/04 H01L 39/14-39/16 H01L 39/20 H01L 21/208 H01L 21/368

Claims (3)

(57) [Claims] 1. A rectangular cross section, which is formed in an annular shape by a plate-like member, and the inner cylindrical portion and a pair of flanges have a U-shaped cross section.
-Shaped winding frame part and one plate thickness of the flange part is the cooling capacity.
Plate of the part that is connected to the cooling container connecting pipe that fixes the vessels
It is a thick flange that is thicker than the
To the support housing cooling vessel via a heat insulating member, the winding frame portion wound with the accommodated in the cooling vessel each have the superconducting coil and the superconducting coil, the to be maintained at a temperature indicating superconductivity two superconducting magnets are oppositely disposed axially, and a connecting tube device having a cooling container connection pipe fixedly connected cooling container with each other above each superconducting magnet, said
The thick flange portion suppresses the superconducting coil from receiving an unbalanced load from the cooling container due to the electromagnetic force when the superconducting coil is excited , and supports the electromagnetic force of the superconducting coil.
A superconducting magnet device, which is characterized in that 2. A plate-shaped member formed into an annular shape having a rectangular cross section.
The inner cylindrical part and the pair of flanges are U-shaped in cross section
-Shaped winding frame part, and the flange is placed inside one of the flange parts.
It has an internal flange provided separately from the lunge section
A cooling container supported and housed in the container via a heat insulating member,
It is wound around the winding frame and housed in the cooling container,
And a superconducting coil that is maintained at a temperature
Having two of the above-mentioned superconducting coils arranged to face each other in the axial direction.
Secure the superconducting magnet and the cooling containers of the above superconducting magnets together.
A connecting pipe device having a cooling container connecting pipe for constant connection is provided,
The inner flange is when the superconducting coil is excited.
The superconducting coil is unbalanced from the cooling container due to electromagnetic force.
Suppresses the load and supports the electromagnetic force of the superconducting coil
A superconducting magnet device characterized by
Place 3. A plate-shaped member having a rectangular cross section and formed into an annular shape.
The inner cylindrical part and the pair of flanges are U-shaped in cross section
-Shaped winding frame is supported and stored in the vacuum container via a heat insulating member.
The cooling container that has been placed and the
Superconductivity stored in a container and maintained at a temperature that exhibits superconducting properties
Conducting coil and the superconducting coil coaxial with the cylindrical portion
Both sides on the outer peripheral side are opposite to the cooling container
Cylindrical reinforcing part arranged in the cooling container so as to be fixed to the plate
And a material, respectively, and face each other in the axial direction of the superconducting coil.
The two superconducting magnets arranged and the above-mentioned superconducting magnets
A connection having a cooling container connecting pipe for fixedly connecting the cooling containers to each other.
A cylindrical connecting member is provided, and the cylindrical reinforcing member is provided with the superconducting coil.
The above superconducting coil is
It suppresses the unbalanced load from the cooling container.
A superconducting magnet device.