JP6021791B2 - Permanent current switch and superconducting device equipped with it - Google Patents

Description

The present invention relates to a permanent current switch that forms a closed circuit through which a permanent current flows by superconductivity, and a superconducting device including the permanent current switch.

For example, in a device that needs to generate a static magnetic field, such as an MRI (magnetic resonance imaging) device or an NMR (nuclear magnetic resonance) device, a superconducting magnet (superconducting magnet) is operated in a permanent current mode to generate a static magnetic field. Permanent current mode means exciting a superconducting magnet with a permanent current, and in order to operate a superconducting magnet in the permanent current mode, a permanent current is passed through a closed circuit composed of superconducting wires and incorporating the superconducting magnet. Must-have.

In order to pass a permanent current through a closed circuit in which a superconducting magnet is incorporated, first, a current is supplied to the superconducting magnet from an external power source of the cut closed circuit, and after the current value flowing through the superconducting magnet reaches the rating, the closed circuit Is connected to confine the supplied current in a closed circuit composed of superconducting wires. This confined current flows through the closed circuit as a permanent current, and the disconnection and connection of the closed circuit is switched by the permanent current switch connected to the superconducting magnet in the closed circuit. This permanent current switch is a member necessary for forming a closed circuit including a superconducting magnet. As the permanent current switch, a thermal type, a magnetic type, a mechanical type, or the like has been devised, but it is easy to manufacture. Therefore, "thermal permanent current switches" are mainly used.

Specifically, the thermal type permanent current switch controls the energization of the heater incorporated inside the permanent current switch itself to bring the superconducting wires constituting the permanent current switch into a superconducting state (switch ON state). Or switch to the normal conduction state (switch OFF state). If the superconducting wire is put into the superconducting state (switch ON state) by this switching, a closed circuit incorporating the superconducting magnet is formed, so that the current supplied from the external power supply is confined in the closed circuit and the superconducting magnet is permanently currented. Can be excited in mode. On the contrary, if the superconducting wire of the permanent current switch is set to the normal conduction state (switch OFF state), the closed circuit is disconnected and the permanent current mode is eliminated.

Such a permanent current switch is already well known, but the configuration and operation thereof have been devised in various ways as shown in Patent Documents 1 to 3.
The permanent current switch disclosed in Patent Document 1 is a switch in a permanent current switch that is connected in parallel with a superconducting coil that is conducted and cooled by a refrigerating machine and that switches the current that is conducted and cooled by the refrigerating machine and flows through the superconducting coil. A cooling member that includes a winding portion around which a superconducting wire is wound, a heater that heats the winding portion, and a heat insulating material that abuts on the winding portion, and conducts and cools the winding portion via the heat insulating material. Is characterized by the arrangement of.

Further, the permanent current switch disclosed in Patent Document 2 is connected to a superconducting coil that is cooled by a cooling source and becomes a superconducting state, and is cooled by conduction from the cooling source to switch the current flowing through the superconducting coil. In the switch, the switch portion having the switch winding portion in which the superconducting wire for the switch connected to the superconducting coil is wound around the winding frame, the heating means for heating the switch winding portion, and the switch portion are fixed. The heat for thermally short-circuiting and disconnecting the switch support member for conducting and cooling the switch winding portion, the low-temperature stage cooled by conduction from the cooling source, and the switch support member and the low-temperature stage. It is characterized by having a switch.

Further, the permanent current switch disclosed in Patent Document 3 is a permanent current switch including a coil composed of a superconducting wire and a heater wire wound on a winding frame, and a cylindrical member is separated from the outside of the coil. It is characterized in that one side of the cylindrical gap formed between the coil and the cylindrical member is opened and the other side is closed, and a plurality of through holes are provided in the closed portion. To do.

Japanese Unexamined Patent Publication No. 10-189324 Japanese Unexamined Patent Publication No. 8-138928 Japanese Unexamined Patent Publication No. 63-81874

By the way, in the permanent current switch disclosed in Patent Document 1, a superconducting wire functioning as a switch is provided so as to be sandwiched between a heat insulating material having a high thermal resistance and a cooling member. The permanent current switch of Patent Document 1 having such a configuration may be able to reduce the load on the refrigerator due to the heat of the heater wire, but it stops the heat generation of the heater wire and returns the superconducting wire to the superconducting state. In this case, excessive time may be required to cool the superconducting wire sandwiched between the heater wire and the heat insulating material.

Further, the permanent current switch disclosed in Patent Document 2 physically separates the refrigerator and the permanent current switch when the switch is turned off, that is, when the temperature of the heater which is the heating means is high, and thermally. Avoid contact. Further, this permanent current switch physically reconnects the refrigerator and the permanent current switch when the switch is turned on, that is, when it is necessary to cool the superconducting wire for the switch.

In such a permanent current switch of Patent Document 2, it is difficult to keep the accuracy of the physical connection (that is, the mechanical connection) in the thermal switch constant in the repeated connection and disconnection, and the connection is made. The accuracy of the connection will be different each time. In addition, the accuracy of the physical connection is greatly affected by individual differences in the thermal switch. Further, by repeating the connection and disconnection, the heat transfer characteristic (that is, the cooling characteristic) may be deteriorated due to the wear of the mechanical connection portion of the heat switch.

Further, the permanent current switch disclosed in Patent Document 3 is provided with a tubular void portion so as to surround the outer periphery of the coil by the superconducting wire, and is immersed in liquid helium. Since the tubular gap portion is open on one side and a through hole is formed on the other side, as long as the permanent current switch is immersed in liquid helium, the tubular gap portion has an open portion on one side. Liquid helium always flows in from the water. That is, even if the liquid helium evaporates due to the heating of the heater wire, the permanent current switch does not have a means for suppressing the inflow of the liquid helium because the helium that has become a gas escapes from the through hole. Liquid helium continues to flow into the part. Therefore, although the tubular void portion can always act as a cooling portion, it is very difficult to act as a heat insulating portion.

As described above, in the conventional permanent current switch, it is difficult to stably and freely switch the connection and disconnection of the switch at a desired timing, and the heat of the heater for disconnecting the switch causes the superconducting coil. It puts a heavy load on the refrigerator for cooling and causes unnecessary evaporation of liquid helium.
Therefore, the present invention can stably and freely switch the connection and disconnection of the switch at a desired timing, and the load and liquid applied to the refrigerator for cooling the superconducting coil by the heat of the heater for disconnecting the switch. It is an object of the present invention to provide a permanent current switch capable of suppressing the amount of evaporation of helium.

In order to achieve the above object, the following technical measures have been taken in the present invention.
The permanent current switch according to the present invention includes a winding frame for winding a coil, a heater wire wound in a coil shape around the winding frame, and a superconducting wire wound in a coil shape so as to overlap the heater wire. A permanent current switch that includes a conducting wire and a housing that supports the winding frame and that interrupts a superconducting circuit including a superconducting coil provided in a superconducting device that is cooled by a refrigerator. It is characterized by having an introduction port for communicating the inside and the outside of the housing and supplying a gas and / or liquid refrigerant inside the housing.

Here, it is preferable that the housing is configured to be thermally connected to the refrigerator.
Further, it is preferable that the housing has a condensing portion that condenses the gaseous refrigerant existing inside the housing into a liquid.
Further, it is preferable that the winding frame is supported on the cooling member of the refrigerator via a heat transfer limiting member that limits the amount of heat transfer.

Further, the winding frame may be supported on the cooling member so that the heat transfer limiting member forms a space between the winding frame and the cooling member.
Here, the winding frame is vertically placed with respect to the cooling member with the axial direction facing up and down, and the heat transfer limiting member supports the upper end side or the lower end side of the winding frame. The space may be formed on the lower end side of the winding frame.

Further, the heat transfer limiting member may be configured to also serve as the housing.
The superconducting device according to the present invention is characterized by having any of the above-mentioned permanent current switches and having a refrigerant supply source for supplying a refrigerant from the outside of the housing of the permanent current switch to the introduction port of the housing. To do.
Here, it is preferable to have a discharge means for discharging the refrigerant inside the housing from the introduction port of the housing to the outside of the housing.

Further, the superconducting device may have a liquid helium for cooling the superconducting coil, and the refrigerant supply source may be the liquid helium.
The most preferable form of the permanent current switch according to the present invention is a winding frame for winding a coil, a heater wire wound in a coil shape around the winding frame, and a coil shape so as to overlap the heater wire. It is a permanent current switch that has a superconducting wire wound around it and a housing that supports the winding frame, and interrupts a superconducting circuit including a superconducting coil provided in a superconducting device cooled by a refrigerator. The permanent current switch has an introduction port that communicates the inside and the outside of the housing and supplies a gas and / or liquid refrigerant to the inside of the housing, and the winding frame limits the amount of heat transfer. It is characterized in that it is supported on the cooling member of the refrigerator via a heat transfer limiting member.

According to the permanent current switch according to the present invention, the connection and disconnection of the switch can be stably and freely switched at a desired timing, and the refrigerator for cooling the superconducting coil by the heat of the heater for disconnecting the switch. It is possible to suppress the load applied to the liquid helium and the amount of evaporation of liquid helium.

It is a figure which shows the structure of the superconducting apparatus provided with the permanent current switch of 1st Embodiment. It is a figure which shows the cross section of a permanent current switch. It is a figure which shows the cross section of the permanent current switch provided with the condensing part. It is a figure which shows the structure of the superconducting apparatus provided with the permanent current switch of 2nd Embodiment. It is sectional drawing which shows the internal structure of the permanent current switch by 3rd Embodiment. It is sectional drawing which shows the internal structure of the permanent current switch by 4th Embodiment. It is sectional drawing which shows the internal structure of the permanent current switch by 5th Embodiment. It is sectional drawing which shows the internal structure of the permanent current switch by 6th Embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the embodiments described below are examples that embody the present invention, and the specific examples do not limit the configuration of the present invention. Therefore, the technical scope of the present invention is not limited to the contents disclosed in the present embodiment. Further, in each of the embodiments described below, the same constituent members will be given the same reference numerals and the same names. Therefore, the same description will not be repeated for the components having the same reference numerals and the same names.

[First Embodiment]
The permanent current switch 1A according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a diagram showing a schematic configuration of a superconducting device 10 which is a magnetic field generator used in an MRI (magnetic resonance imaging) device, an NMR (nuclear magnetic resonance) device, and the like. FIG. 2 is a cross-sectional view showing the internal configuration of the permanent current switch 1A.

First, the configuration of the superconducting device 10 provided with the permanent current switch 1A will be described with reference to FIG.
The superconducting device 10 includes a storage container 2, a superconducting coil 3 stored in the storage container 2, a vacuum container 4 that holds the storage container 2 inside so that the outer surface of the storage container 2 does not come into contact with the air at room temperature, and the like. It has a cooling means 5 for cooling the superconducting coil 3 to a temperature equal to or lower than the superconducting transition temperature.

The storage container 2 is a hollow container made of a material having excellent mechanical strength and corrosion resistance, such as thin-walled stainless steel. The storage container 2 stores the superconducting coil 3 described in detail later and also stores the cooling means 5, whereby the superconducting coil 3 in the storage container 2 is cooled to the superconducting transition temperature or lower.
The superconducting transition temperature is an extremely low temperature of several K (Kelvin) in terms of thermodynamic temperature. Therefore, when the storage container 2 made of a material having high thermal conductivity such as stainless steel is placed at room temperature, heat enters the storage container 2 from the room temperature, so that the inside of the storage container 2 is kept below the superconducting transition temperature. Is difficult. Therefore, the storage container 2 is held in a vacuum container 4, which will be described later, in which the inside is evacuated so that the outer surface does not come into contact with the atmosphere at room temperature.

The superconducting coil 3 is a coil obtained by winding a wire rod made of a superconductor (superconducting substance), and is housed in a storage container 2. When a current is supplied to the superconducting coil 3 below the superconducting transition temperature, the supplied current continues to flow through the superconducting coil having an electric resistance of almost zero as a so-called permanent current. The superconducting coil 3 generates a magnetic field by electromagnetic induction caused by this permanent current.

Further, a power supply unit (external power supply) that supplies a current to the superconducting coil 3 can be connected to the superconducting coil 3, and in order to form a closed circuit through which a permanent current flows, a permanent power supply unit, which will be described later, is formed. The current switch 1A is connected to the superconducting coil 3. By switching ON (connection) and OFF (disconnection) of the permanent current switch 1A, it is possible to switch the formation and elimination of a closed circuit through which a permanent current flows. If the permanent current switch 1A is connected, a closed circuit is formed and disconnection. If this is done, the closed circuit will be eliminated. At this time, the cable forming the closed circuit is formed from the superconductor like the superconducting coil 3.

Like the storage container 2, the vacuum container 4 is a hollow container made of a material having excellent mechanical strength and corrosion resistance, such as stainless steel, and holds the storage container 2 for storing the superconducting coil 3 inside. To do. The vacuum container 4 holds the storage container 2 in a vacuum so that the outer surface of the storage container 2 having an extremely low temperature such as the superconducting transition temperature or lower does not come into contact with the air at room temperature. In other words, the vacuum container 4 holds the storage container 2 across the vacuum space. That is, the storage container 2 and the vacuum container 4 form a so-called thermos structure, and the storage container 2 and the room temperature are insulated from each other by separating the vacuum space by the vacuum container 4.

The cooling means 5 is, for example, a cryogenic refrigerator (hereinafter, simply referred to as a refrigerator) such as a GM (Gifford McMahon) refrigerator. The refrigerator (hereinafter referred to as the refrigerator 5) which is the cooling means 5 is rod-shaped and long, has a drive unit 50 including a compressor or the like on one end side, and further goes from the drive unit 50 to the other end. It has a two-stage configuration with a first-stage stage 51 for heat exchange in the middle and a second-stage stage 52 on the other end side. The first stage stage 51 is a heat exchange unit that can be cooled to, for example, about 30 K, and the second stage stage 52 is a heat exchange unit that can be cooled to about 4 K.

As shown in FIG. 1, the refrigerator 5 penetrates the vacuum container 4 and the storage container 2 from the outside of the vacuum container 4 and holds the second stage stage 52 inside the storage container 2. The drive unit 50 of the refrigerator 5 is airtightly held around the through hole of the vacuum container 4, the first stage stage 51 is tightly connected to the storage container 2, and the second stage stage 52 is inside the storage container 2. It is connected to the superconducting coil 3 via a plate-shaped cooling member 6 having a low thermal resistance (for example, a copper member). Here, the cooling member 6 can be seen as an extension of the second stage stage 52. As shown in FIG. 1, by connecting the superconducting coil 3 to the second stage stage 52, the superconducting coil 3 can be cooled to a temperature below the superconducting transition temperature of, for example, 4K.

The superconducting device 10 having the above configuration further includes a permanent current switch 1A. Hereinafter, the permanent current switch 1A will be described with reference to FIGS. 1 and 2.
As described above, the permanent current switch 1A is connected to the superconducting coil 3 by a conducting wire (cable) in order to form a closed circuit through which a permanent current flows, and the winding frame 11, the heater wire 12, and the switch portion 13 are connected. , And a housing (outer cylinder member) 14 for storing these inside.

The winding frame 11 is, for example, a member having a cylindrical body portion M having an outer diameter of about 15 mm, and in order to suppress heat transfer of heat generated by the heater wire 12 described later, for example, heat of GFRP (glass fiber reinforced plastic) or the like is used. It is made of a material with high resistance. The winding frame 11 has disc-shaped flat plates (flange) F1 and F2 at both ends of a cylindrical body portion M, and is configured as a so-called bobbin. One flange F1 of the winding frame 11 is provided with an introduction port (through hole T) along the longitudinal direction of the body portion M at a position not overlapping with the body portion M.

The heater wire 12 is a conductive member such as a constantan wire that generates heat when energized. For example, the heater wire 12 is wound around a winding frame having an outer diameter of 15 mm in a coil shape with a winding width of about 100 mm and a length corresponding to 100 Ω.
The switch unit 13 is a superconducting wire composed of a superconductor such as CuNi / NbTi, so that the length at which the resistance at both ends at room temperature is 100Ω overlaps with the heater wire 12 wound around the winding frame 11. It is wound in a coil shape with no induction winding. When the switch unit 13 is cooled below the superconducting transition point, the electric resistance becomes almost zero 0, so that the switch unit 13 is turned on (connected). If the heat generated by the heater wire 12 exceeds the superconducting transition point, electric resistance is generated. Therefore, it is in the OFF (disconnect) state.

The outer cylinder member 14 is a cylindrical member made of a material having a low thermal resistance such as copper, and the winding frame 11 around which the heater wire 12 and the switch portion 13 are wound is enclosed in the cylinder and wound. The winding frame 11 is held by airtightly connecting to the flanges F1 and F2 of the frame 11. At this time, the outer cylinder member 14 has an inner diameter sufficient to secure a space S at a predetermined interval from the switch portion 13.

As described above, by holding the winding frame 11 around which the heater wire 12 and the switch portion 13 are wound in the outer cylinder member 14, the permanent current switch 1A having the cross-sectional configuration as shown in FIG. 2 is configured. The ends of the heater wire 12 and the switch portion 13 are drawn out of the permanent current switch 1A, and the heater wire 12 is connected to an external power source of the superconducting device 10.
Further, the permanent current switch 1A is provided with a copper conduit P for communicating the inside and the outside of the permanent current switch 1A in the through holes T formed in the flanges F1 and F2 of the winding frame 11. By this conduit P, a gas and / or liquid refrigerant can be supplied to the inside of the permanent current switch 1A, and the inside of the permanent current switch 1A can be exhausted. The supply and exhaust of the refrigerant will be described later as the operation of the permanent current switch 1A.

The arrangement of the permanent current switch 1A in the superconducting device 10 will be described with reference to FIG. 1 again. In the permanent current switch 1A, the outer cylinder member (housing) 14 physically contacts the plate-shaped cooling member (for example, a copper member) 7 having a low thermal resistance at a position where the influence of the magnetic field generated by the superconducting coil 3 is small. The cooling member 7 is physically connected to the second stage 52 of the refrigerator 5. Here, the cooling member 7 can be seen as an extension of the second stage stage 52. In this way, since the permanent current switch 1A is thermally connected to the second stage 52 of the refrigerator 5, it is cooled to the vicinity of 4.2K, which is the superconducting transition point of the switch unit 13.

On top of that, the exhaust pump 8 provided outside the superconducting device 10 and the refrigerant supply source 9 are connected to the copper conduit P provided on the flange F1 of the winding frame 11. The exhaust pump 8 is a pump (exhaust means) that exhausts the inside of the permanent current switch 1A, and the refrigerant supply source 9 is a supply source that supplies helium gas to the inside of the permanent current switch 1A. The pipe connecting the refrigerant supply source 9 and the conduit P provided on the flange F1 is connected to the cooler 5 inside the storage container 2 so that the helium gas reaches the permanent current switch 1A as close to 4.2K as possible. On the other hand, it has a structure that takes a heat anchor. Further, an on-off valve V1 or V2 is provided in the piping of the exhaust pump 8 and the refrigerant supply source 9, respectively.

The operation of the permanent current switch 1A having the above configuration will be described below.
First, the operation of the permanent current switch 1A will be explained while explaining the process of exciting the superconducting coil 3 by passing a permanent current through the superconducting coil 3 from a state in which the superconducting coil 3 is cooled below the superconducting transition point by the refrigerator 5 and not excited. To do.
First, in the superconducting device 10, in a state where the superconducting coil 3 is cooled below the superconducting transition point such as 4.2K, the heater wire 12 of the permanent current switch 1A is energized to raise the temperature of the switch unit 13 above the superconducting transition point. Maintaining. As a result, the permanent current switch 1A is in a state in which the switch unit 13 is turned off (disconnected) and the closed circuit for passing the permanent current through the superconducting coil 3 is eliminated. At this time, the inside of the permanent current switch 1A is almost evacuated by the exhaust pump 8, and the heater wire 12 and the outer cylinder member 14 of the permanent current switch 1A are in the vacuum space S.
Insulated by. Therefore, the outer cylinder member 14 of the permanent current switch 1A is cooled by the refrigerator 5 and kept at a temperature equal to or lower than the superconducting transition point.

From this state, a current is supplied to the superconducting coil 3 from an external power source of the superconducting device 10 by a well-known method to excite the superconducting coil 3. After the current flowing through the superconducting coil 3 reaches the rating, the energization of the heater wire 12 is stopped, the on-off valve V1 on the exhaust pump 8 side is closed, and the on-off valve V2 on the refrigerant supply source 9 side is opened to permanently release the helium gas. It flows into the current switch 1A. The temperature of the outer cylinder member 14 of the permanent current switch 1A rises slightly due to the inflowing helium gas, and the heat load of the refrigerator 5 rises. However, at this time, the superconducting coil 3 has already generated a rated magnetic field, and the AC heat generated by the superconducting coil 3 which is the main heat source during the excitation operation is contained, so that the heat load of the inflowing helium gas is transferred to the refrigerator 5. Even if it is added, it does not become a large load. However, in order to further reduce the load on the refrigerator 5, the helium gas may be cooled in advance by the refrigerant supply source 9.

The helium gas flowing into the permanent current switch 1A is cooled to 4.2 K or less by touching the inner wall of the outer cylinder member 14, recondensed in liquid helium, and stored in the outer cylinder member 14. In this way, the heater wire 12 is cooled by the helium gas and liquid helium existing in the permanent current switch 1A, and the switch portion 13 is cooled below the superconducting transition point. At this time, it is more preferable that the helium gas supplied from the refrigerant supply source 9 is cooled so as to be liquefied before reaching the permanent current switch 1A.

When the switch unit 13 is cooled below the superconducting transition point, the switch unit 13 of the permanent current switch 1A is turned on (connected), and a closed circuit for passing a permanent current through the superconducting coil 3 is formed. The external power supply to which the current is supplied is disconnected from the superconducting coil 3. Through this series of operations, the superconducting coil 3 is operated in a permanent current mode in which a permanent current flows, and can continue to generate a magnetic field.

To stop the operation of the superconducting coil 3, the on-off valve V2 on the refrigerant supply source 9 side is closed and the on-off valve V1 on the exhaust pump 8 side is opened to exhaust the inside of the permanent current switch 1A to a vacuum. The heater wire 12 is energized at the same time as or after the exhaust, and the temperature of the switch unit 13 is raised to a temperature exceeding the superconducting transition point. When the temperature of the switch unit 13 exceeds the superconducting transition point, the switch unit 13 is turned off (disconnected), and the closed circuit in which the permanent current flows through the superconducting coil 3 is eliminated, so that the permanent current does not flow through the superconducting coil 3. , The superconducting coil 3 stops the generation of the magnetic field. At this time, the space S in the permanent current switch 1A is filled with helium gas having a high thermal resistance vaporized by the heat of the heater wire 12 for the liquid helium stored inside, so that the heater wire 12, the switch portion 13, and the outer cylinder The member 14 is substantially insulated by the space S.

As described above, since liquid helium is accumulated inside the permanent current switch 1A, in order to efficiently use the liquid helium such as enhancing the cooling effect of the switch portion 13 by the liquid helium, FIGS. 1 and 2 are shown. As shown, the permanent current switch 1A is placed horizontally so that the longitudinal direction of the body M of the winding frame 11 is substantially perpendicular to the direction of gravity (that is, the body M is horizontal). Is preferable.

When the permanent current switch 1A described in the present embodiment is used, when the permanent current switch 1A is turned off, the inside of the permanent current switch 1A can be filled with helium gas having high thermal resistance or exhausted to a vacuum state. It can be held in a heat-insulated state. As a result, the thermal resistance between the heat generating portion of the permanent current switch 1A and the refrigerator 5 can be increased, and the load on the refrigerator 5 can be reduced. Further, when the permanent current switch 1A is turned on, the heat of the heater wire 12 can be absorbed by the liquid helium condensed in the liquid inside the permanent current switch 1A, and the switch unit 13 can be kept in the superconducting state. .. With such a configuration, the permanent current switch 1A can hold the inside of the permanent current switch 1A in a heat-insulated state in the OFF state (the switch unit 13 is in the normal conduction state), so that the heater wire 12 is energized. The heat generated by the above is hardly transmitted to the refrigerator 5 side. Further, in the permanent current switch 1A, in the ON state (the switch unit 13 is in the superconducting state), the switch unit 13 can be cooled by a refrigerant such as liquid helium to maintain the superconducting state, so that stable switching operation can be realized. ..

Finally, it was explained that the helium gas introduced into the permanent current switch 1A is cooled to 4.2 K or less by touching the inner wall of the outer cylinder member 14 and recondensed into liquid helium. In order to raise the current, a permanent current switch 1B having a condensing portion 15 formed on the inner wall of the outer cylinder member (housing) 14 may be used as shown in FIG. Specifically, the condensing portion 15 is a groove formed on the inner wall of the outer cylinder member, and by forming such a groove, the surface area of the inner wall of the outer cylinder member 14 can be increased, and the helium gas and the outer surface can be increased. Heat exchange between the inner walls of the tubular member 14 becomes easy.

[Second Embodiment]
A second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a diagram showing a schematic configuration of a superconducting device 20 which is a magnetic field generator used in an MRI (magnetic resonance imaging) device, an NMR (nuclear magnetic resonance) device, and the like. In the present embodiment, the superconducting device 20 has substantially the same configuration as the superconducting device 10 described in the first embodiment, and is provided with the permanent current switch 1A or 1B also described in the first embodiment.

The configuration of the superconducting device 20 provided with the permanent current switch 1A will be described with reference to FIG.
In the superconducting device 20, the superconducting coil 3 is immersed in liquid helium H. Further, the second stage 52 of the refrigerator 5 is provided with fins 53 for recondensing the helium gas vaporized in the storage container 2 without being immersed in the liquid helium H. Further, between the storage container 2 and the vacuum container 4, a shielding shield 16 for shielding heat due to radiation entering the storage container 2 from the outside of the superconducting device 20 is provided.

In the superconducting device 20 having such a configuration, the permanent current switch 1A is supported by the cooling member 7 as in the first embodiment, and is thermally connected to the second stage 52 of the refrigerator 5 to be cooled. ing. On top of that, the conduit P provided on the flange F1 of the winding frame 11 of the permanent current switch 1A is arranged so that an opening is arranged in the vicinity of the fin 53 provided on the second stage 52 of the refrigerator 5. It is piped.

Even if the permanent current switch 1A is used in the superconducting device 20 as in the present embodiment, the same effect as that of the permanent current switch 1A in the first embodiment can be obtained. That is, when the permanent current switch 1A in the present embodiment is turned off, the heater wire 12 generates heat, so that the inside of the permanent current switch 1A is filled with helium gas having a relatively high temperature, and the outer cylinder member 14 and the outer cylinder member 14. The thermal insulation between the heater wire 12 and the switch portion 13 can be improved. At this time, the pressure inside the permanent current switch 1A rises as the temperature rises due to the heat generated by the heater wire 12, and the helium gas inside is discharged from the permanent current switch 1A. However, since the discharged helium gas is discharged in the vicinity of the recondensing fin 53 provided in the second stage 52 of the refrigerator 5, the fin 53 recondenses the discharged helium gas into liquid helium.

Further, when the permanent current switch 1A is turned on, the heater wire 12 does not generate heat, so that the permanent current switch 1A is cooled to 4.2 K or less by the refrigerator 5. Due to this cooling, the pressure inside the permanent current switch 1A becomes lower than that outside the permanent current switch 1A. Therefore, due to this pressure difference, a relatively low temperature helium gas near the fins 53 provided in the second stage stage 52. Is introduced into the permanent current switch 1A through the conduit P provided in the flange F1. The helium gas introduced into the permanent current switch 1A is cooled to 4.2 K or less by touching the inner wall of the outer cylinder member 14, recondensed in liquid helium, and stored inside the permanent current switch 1A.

As described in the present embodiment, in the case of the superconducting device 20 having a configuration in which the superconducting coil 3 is immersed in the liquid helium H and cooled, the exhaust pump 8 as described in the first embodiment for the permanent current switch 1A. And the refrigerant supply source 9 need not be connected. If the conduit P of the permanent current switch 1A is configured so that the liquid helium H in the storage container 2 or the helium gas evaporated from the liquid helium H is used instead of the refrigerant supply source 9, for example, the permanent current switch 1A is in the OFF state. At this time, the inside of the permanent current switch 1A can be maintained in a heat-insulated state such as being filled with helium gas or the like having a high thermal resistance. As a result, the thermal resistance between the heat generating portion of the permanent current switch 1A and the refrigerator 5 can be increased, and the load on the refrigerator 5 can be reduced. Further, when the permanent current switch 1A is turned on, the heat of the heater wire 12 can be absorbed by the liquid helium condensed in the liquid inside the permanent current switch 1A, and the switch unit 13 can be kept in the superconducting state. .. With such a configuration, the permanent current switch 1A can hold the inside of the permanent current switch 1A in a heat-insulated state in the OFF state (the switch unit 13 is in the normal conduction state), so that the heater wire 12 is energized. The heat generated by the above is hardly transmitted to the refrigerator 5 side. Further, in the permanent current switch 1A, in the ON state (the switch unit 13 is in the superconducting state), the switch unit 13 can be cooled by a refrigerant such as liquid helium to maintain the superconducting state, so that stable switching operation can be realized. ..

[Third Embodiment]
A third embodiment of the present invention will be described with reference to FIG.
FIG. 5 is a cross-sectional view showing the internal configuration of the permanent current switch 1C according to the present embodiment. The permanent current switch 1C according to the present embodiment is a permanent current switch used in a superconducting device such as the superconducting device 10 according to the first embodiment and the superconducting device 20 according to the second embodiment, and is the same as the above-mentioned permanent current switches 1A and 1B. By switching between ON (connection) and OFF (disconnection), it is possible to switch the formation and elimination of a closed circuit through which a permanent current flows. In the following description, as an example, a case where the permanent current switch 1C is provided in the superconducting device 10 will be described.

The configuration of the permanent current switch 1C will be described with reference to FIG. In each embodiment after this embodiment, the direction in which the cooling member 7 is substantially perpendicular to the mounting surface, which is the surface on which the permanent current switch is mounted, is referred to as an upper direction, and vice versa. The direction approaching is called downward. When the permanent current switch 1C of FIG. 5 is arranged like the superconducting device 10 shown in FIG. 1, the lower part corresponds to the direction of gravity.

As described above, the permanent current switch 1C is connected to the superconducting coil 3 by a conducting wire (cable) in order to form a closed circuit through which a permanent current flows. The permanent current switch 1C includes a winding frame 11, a heater wire 12, a switch portion 13, a housing 14A for storing these, a support portion 17 for supporting the winding frame 11 in the housing 14A, and a housing. It includes a conduit P1 that introduces helium gas into the body 14A and discharges helium gas from the housing 14A, and a temperature sensor 18 that measures the temperature of the helium gas introduced into the housing 14A. In the present embodiment, the winding frame 11 is made of copper, but may be made of a metal such as stainless steel or GFRP.

The winding frame 11, the heater wire 12, and the switch unit 13 have substantially the same configurations as those in the permanent current switches 1A and 1B described in the first embodiment. However, in the present embodiment, the flange F1 of the winding frame 11 is not provided with the through hole T.
The housing 14A has a shape that can be arranged on the cooling member 7 of the refrigerator 5, such as a rectangular parallelepiped shape, a cubic shape, and a cylindrical shape, and is a winding frame 11 around which the heater wire 12 and the switch portion 13 are wound. It is a hollow container having a size capable of storing a switch, and is made of a material having excellent mechanical strength and corrosion resistance, such as thin-walled stainless steel. As shown in FIG. 5, the housing 14A arranged on the cooling member 7 is an airtight container, but the through hole T1 connecting the inside and the outside of the housing 14A and connecting the conduit P1 described later is formed. It is formed at a position sufficiently distant from the cooling member 7 so that the liquid helium accumulated inside does not leak to the outside of the housing 14A.

As shown in FIG. 5, the support portion 17 supports the winding frame 11 in the housing 14A so as not to come into contact with the housing 14A and positions the winding frame 11 with respect to the housing 14A. It is a columnar or block-shaped member having strength to support 11. The support portion 17 is made of a resin such as GFRP, which has a lower thermal conductivity than metal.
The support portion 17 positions the winding frame 11 by supporting the flanges F1 and F2 of the winding frame 11 arranged so that the body portion M is substantially parallel to the cooling member 7 in the housing 14A. The support portion 17 is arranged above and below the flange F1 so as to be sandwiched between the flange F1 and the housing 14A, and supports the flange F1 with respect to the housing 14A. The support portion 17 supports and positions the entire winding frame 11 in the housing 14A by supporting the flange F2 as well as the flange F1. At this time, the support portion 17 has the winding frame 11 in the housing 14A so as to have a substantially equal space (space) from the upper and lower wall surfaces of the housing 14A and a substantially equal space (space) from the left and right wall surfaces. It is preferable to support it near the center of the.

Such a support portion 17 supports, for example, two points below the circumferential surfaces of the disc-shaped flanges F1 and F2 by the two support portions 17, and also above the circumferential surfaces of the flanges F1 and F2. The two points of the above are supported by two support portions 17. That is, each of the flanges F1 and F2 is supported at four points by using four support portions 17 in which the circumferential surfaces of the flanges F1 and F2 are vertically combined. At this time, it is preferable that the support portion 17 is formed in a shape in contact with the flanges F1 and F2 and the housing 14A in an area as small as the strength allows. By making the area of contact between the flanges F1 and F2 and the housing 14A as small as possible, the amount of heat transfer between the flanges F1 and F2 and the housing 14A can be made as small as possible.

The support portion 17 having the above-described configuration is also a heat transfer limiting member that limits the amount of heat transfer between the flanges F1 and F2 and the housing 14A, and the winding frame 11 is passed through the support portion 17 that is the heat transfer limiting member. It can be supported on the cooling member 7 of the refrigerator 5 in the housing 14A. The support portion 17, which is a heat transfer limiting member, supports the winding frame 11 on the cooling member 7 as described above, and forms a space S between the winding frame 11 and the cooling member 7. When the space S between the winding frame 11 and the cooling member 7 is evacuated by exhausting the inside of the housing 14A to a vacuum, a vacuum heat insulating layer is formed between the winding frame 11 and the housing 14A (cooling member 7). It is formed. Therefore, the heat transfer between the winding frame 11 and the housing 14A is substantially limited to the heat transfer via the heat transfer limiting member between the flanges F1 and F2 and the housing 14A. It is possible to effectively insulate the space between (cooling members 7).

As shown in FIG. 5, the conduit P1 is a pipe body made of stainless steel that is connected to a through hole T1 provided above the housing 14A and for communicating the inside and the outside of the housing 14A. The conduit P1 is connected to an exhaust pump 8 provided outside the superconducting device and a refrigerant supply source 9 as in the conduit P according to the first embodiment. By connecting the conduit P1 that communicates the inside and the outside of the housing 14A to the exhaust pump 8 and the refrigerant supply source 9, helium gas and / or liquid helium is inside the housing 14A, that is, inside the permanent current switch 1C. Can be supplied, and the inside of the permanent current switch 1C can be exhausted.

However, since it is difficult to smoothly supply a liquid refrigerant such as liquid helium to the inside of the permanent current switch 1C through the conduit P1, a gaseous helium gas is usually supplied to the conduit P1. The helium gas that has flowed into the housing 14A through the conduit P1 is cooled and liquefied by the housing 14A in contact with the cooling member 7, becomes liquid helium, and accumulates inside the housing 14A (inside the permanent current switch 1C). ..

Therefore, in order to prevent the helium gas flowing through the conduit P1 from being liquefied, the conduit P1 needs to be kept at a predetermined temperature, and a heater wire 19 that generates heat by an electric current is wound around the conduit P1 like the heater wire 12. There is. If the conduit P1 is maintained at a predetermined temperature by the heat generated by the heater wire 19, it is possible to prevent the helium gas flowing through the conduit P1 from liquefying in the middle of the conduit P1 and becoming a plug that closes the conduit P1.

If the conduit P1 is made of copper having a high thermal conductivity, helium gas is likely to be liquefied in the conduit P1. Therefore, it is preferable to construct the conduit P1 using stainless steel having a low thermal conductivity among metals.
The temperature sensor 18 is a sensor that measures the temperature of the helium gas flowing through the conduit P1. As shown in FIG. 5, the temperature sensor 18 is provided in the vicinity of the through hole T1 which is the joint portion between the conduit P1 and the housing 14A in the housing 14A, and immediately before flowing into the housing 14A through the conduit P1. Alternatively, measure the temperature of the helium gas immediately after the inflow.

The position where the temperature sensor 18 is provided is not limited to the position shown in FIG. 5, and may be on the conduit P1.
In FIG. 5, the conduit P1 is provided above the flange F1 side of the winding frame 11 in the housing 14A, but the conduit P2 shown by the broken line similar to the conduit P1 is shown on the flange F2 side of the winding frame 11 in the housing 14A. It may be provided above. That is, in the housing 14A, the conduit P2 for exhausting the helium gas in the housing 14A is provided on the side opposite to the conduit P1 with the winding frame 11 interposed therebetween.

A check valve is provided in the middle of the path of the conduit P2 to allow the outflow from the housing 14A to the outside but restrict the inflow from the outside to the housing 14A, and the conduit P2 having this check valve is connected to the exhaust pump 8. Then, a one-way flow path can be formed in which the helium gas that has flowed into the housing 14A from the conduit P1 is discharged from the housing 14A to the conduit P2, and the helium gas can be smoothly introduced and discharged. it can.

When the permanent current switch 1C according to the present embodiment is used, the high heat insulating property between the heat switch, which is the winding frame 11 around which the heater wire 12 and the switch portion 13 are wound, and the cooling member 7 of the refrigerator 5 is provided, and the support portion 17 is provided. Since it is obtained by the space S between the winding frame 11 and the cooling member 7, the heat generated by the heater wire 12 hardly escapes to the cooling member 7. As a result, the permanent current switch 1C can be turned off (cut off) by generating less heat from the heater wire 12.

In the above description, the case where the permanent current switch 1C is provided in the superconducting device 10 has been described. However, similarly to the permanent current switch 1B, the permanent current switch 1C is not provided with the exhaust pump 8 and the refrigerant supply source 9. It can also be provided at 20.
[Fourth Embodiment]
A fourth embodiment of the present invention will be described with reference to FIG.

FIG. 6 is a cross-sectional view showing the internal configuration of the permanent current switch 1D according to the present embodiment. The permanent current switch 1D according to the present embodiment is a permanent current switch used in a superconducting device such as the superconducting device 10 according to the first embodiment and the superconducting device 20 according to the second embodiment, and is the same as the above-mentioned permanent current switches 1A to 1C. By switching between ON (connection) and OFF (disconnection), it is possible to switch the formation and elimination of a closed circuit through which a permanent current flows. In the following description, as an example, a case where the permanent current switch 1D is provided in the superconducting device 10 will be described.

The configuration of the permanent current switch 1D will be described with reference to FIG.
As shown in FIG. 6, the permanent current switch 1D includes a winding frame 11A having substantially the same configuration as the winding frame 11 described in the above embodiment, and a winding frame 11A around which the heater wire 12 and the switch portion 13 are wound. It is provided with a support portion 17A that supports the heat switch) on the cooling member 7. The permanent current switch 1D has a configuration in which the winding frame 11A is vertically placed on the mounting surface on which the permanent current switch 1D is mounted in the cooling member 7. That is, the winding frame 11A is arranged so that the axis of the winding frame 11A is substantially perpendicular to the mounting surface along the vertical direction, and is supported on the cooling member 7 by the support portion 17A.

The winding frame 11A has substantially the same structure as the winding frame 11, and includes a body portion M and flanges F1a and F2 which are two disc-shaped flat plates. The structure of the winding frame 11A that differs from that of the winding frame 11 is the shape of the flange F1a.
The flange F1a is a disc-shaped flat plate having a diameter larger than that of the flange F2, is concentric with the body portion M and the flange F2, and is above the flange F2 when the winding frame 11A is arranged on the cooling member 7. Is placed in. By supporting the flange F1a having a diameter larger than that of the flange F2 from below while ensuring a space S between the flange F2 and the cooling member 7, the winding frame 11A is vertically placed with respect to the cooling member 7.

As shown in FIG. 6, the support portion 17A is a member that supports the flange F1a of the winding frame 11A (that is, the upper end side of the winding frame 11A) from below, and is formed in a cylindrical shape having substantially the same diameter as the flange F1a. It is a stainless steel cylinder. The support portion 17A is a thin-walled tubular body having a total length larger than the axial length of the winding frame 11A, and the permanent current switch 1D in the cooling member 7 opens an opening at one end of the tubular body (support portion 17A). A winding frame that is airtightly fixed to the mounting surface, which is the surface on which the cylinder is mounted, and is inserted into the cylinder (support portion 17A) from the flange F2 side at the opening side of the other end of the cylinder (support portion 17A). The flange F1a of 11A is supported. If the opening side of the other end of the support portion 17A and the flange F1a of the winding frame 11A are hermetically bonded or joined, the winding frame 11A can be hermetically held in the cylindrical support portion 17A.

The support portion 17A having the above-described configuration is formed as thin as possible in order to minimize the amount of heat transfer between the flange F1a and the cooling member 7, and acts as a heat transfer limiting member. Due to the support portion 17A having such a configuration, the flange F2 of the winding frame 11A is separated from the cooling member 7 by a length longer than the length along the axial direction of the winding frame 11A in the total length of the support portion 17A, and the flange F2 A space S is formed below (that is, on the lower end side of the winding frame 11A).

In addition to storing and supporting the winding frame 11A inside the support portion 17A, the inside of the support portion 17A is exhausted to a vacuum, so that the winding frame 11A is between the support portion 17A and the cooling member 7. Since the vacuum layer (heat insulating layer) including the space S is formed in the space S, in addition to the function as a heat transfer limiting member, the function of the housing 14A in the third embodiment is also realized. Therefore, it can be said that the support portion 17A, which is a heat transfer limiting member, is configured to also serve as a housing.

Here, as shown in FIG. 6, a through hole T1 and a conduit P1 described in the third embodiment are provided above the support portion 17A, connected to the exhaust pump 8 and the refrigerant supply source 9, and into the support portion 17A. Helium gas can be introduced and exhausted.
At this time, the conduit P1 is preferably in the vicinity of the portion where the flange F1a and the support portion 17A are bonded or joined. The heater wire 19 may be wound around the conduit P1 as in the third embodiment. Further, the support portion 17A may be provided with the conduit P2 described in the third embodiment and connected to the exhaust pump 8. Further, a temperature sensor 18 may be provided in the vicinity of the through hole T1 and the conduit P1 to measure the temperature of the helium gas immediately before or immediately after the inflow into the support portion 17A.

If the permanent current switch 1D having the above configuration is used, the amount of heat transfer to the thin-walled support portion 17A having low thermal conductivity is very small, so that the heat path is transferred from the flange F1a through the support portion 17A to the cooling member 7. The amount of heat can be kept very small. In addition to this, the high heat insulating property between the winding frame 11A around which the heater wire 12 and the switch portion 13 are wound and the cooling member 7 of the refrigerator 5 is provided between the supporting portion 17A and the winding frame 11A and the cooling member 7. Since it is obtained by the space S, the heat generated by the heater wire 12 hardly escapes to the cooling member 7. As a result, the permanent current switch 1D, which can turn off (cut) the switch operation by generating less heat from the heater wire 12, has a simple configuration using a support portion 17A that also serves as a heat transfer limiting member and a housing. It can be realized.

In the above description, the case where the permanent current switch 1D is provided in the superconducting device 10 has been described. However, similarly to the permanent current switch 1B, the permanent current switch 1D is not provided with the exhaust pump 8 and the refrigerant supply source 9. It can also be provided at 20.
[Fifth Embodiment]
A fifth embodiment of the present invention will be described with reference to FIG. 7.

FIG. 7 is a cross-sectional view showing the internal configuration of the permanent current switch 1E according to the present embodiment. The permanent current switch 1E according to the present embodiment is a permanent current switch used in a superconducting device such as the superconducting device 10 according to the first embodiment and the superconducting device 20 according to the second embodiment, and is the same as the above-mentioned permanent current switches 1A to 1D. By switching between ON (connection) and OFF (disconnection), it is possible to switch the formation and elimination of a closed circuit through which a permanent current flows. In the following description, as an example, a case where the permanent current switch 1E is provided in the superconducting device 10 will be described.

The configuration of the permanent current switch 1E will be described with reference to FIG. 7.
As shown in FIG. 7, in the permanent current switch 1E, the winding frame 11 described in the above-described embodiment and the winding frame 11 (heat switch) around which the heater wire 12 and the switch portion 13 are wound are placed on the cooling member 7. It is provided with a support portion 17B for supporting. Similar to the permanent current switch 1D, the permanent current switch 1E has a configuration in which the winding frame 11 is vertically placed on the mounting surface on which the permanent current switch 1E is mounted in the cooling member 7. .. That is, the winding frame 11 is arranged so that the axis of the winding frame 11 is substantially perpendicular to the mounting surface along the vertical direction, and is cooled via the support portion 17B, that is, across the support portion 17B. It is supported on the member 7. In FIG. 7, the winding frame 11 is vertically arranged so that the flange F1 is upward, but the winding frame 11 may be vertically arranged so that the flange F2 is upward.

The support portion 17B is fixed to a flange (for example, flange F2) below the vertically placed winding frame 11 (that is, the lower end side of the winding frame 11), and is fixed on the cooling member 7 to wind the support portion 17B. The lower end side of the winding frame 11 is supported with respect to the cooling member 7 while securing a space S between the frame 11 and the cooling member 7. The support portion 17B is, for example, a member having a cylindrical shape having a bottom surface having substantially the same size and shape as the disk-shaped flange F2 and having a hollow inside, and is made of a metal such as stainless steel.

The cylindrical support portion 17B having such a configuration is in contact with the flange F2 on the lower end side of the winding frame 11 on one bottom surface (end face) and in contact with the cooling member 7 on the other bottom surface (end face). At this time, the hollow portion inside the support portion 17B forms a space S that separates the flange F2 of the winding frame 11 from the cooling member 7, and when this space S is exhausted to a vacuum, between the flange F2 and the cooling member 7. A vacuum insulation layer is formed on the floor. With this heat insulating layer, the space between the winding frame 11 and the cooling member 7 can be effectively heat-insulated. In order to effectively obtain the heat insulating effect of the vacuumed space S, it is preferable to use stainless steel having a lower thermal conductivity than copper for the support portion 17B, and the support portion 17B is configured to be as thin as possible. It is good to do.

Here, as shown in FIG. 7, a through hole T1 and a conduit P1 described in the third embodiment are provided above the support portion 17B to connect to the exhaust pump 8 and the refrigerant supply source 9, and enter the support portion 17B. Helium gas can be introduced and exhausted.
At this time, the conduit P1 is preferably in the vicinity of the portion where the support portion 17B and the flange F2 are bonded or joined. The heater wire 19 may be wound around the conduit P1 as in the third embodiment. Further, the support portion 17B may be provided with the conduit P2 described in the third embodiment and connected to the exhaust pump 8. Further, a temperature sensor 18 may be provided in the vicinity of the through hole T1 and the conduit P1 to measure the temperature of the helium gas immediately before or immediately after the inflow into the support portion 17B.

If the permanent current switch 1E having the above configuration is used, high heat insulation between the winding frame 11 and the cooling member 7 of the refrigerator 5 can be obtained by the space S in the support portion 17B, and a thin wall having a low thermal conductivity can be obtained. Since the heat transfer amount of the support portion 17B is very small, the heat transfer amount of the heat path from the flange F2 to the cooling member 7 through the support portion 17B can be suppressed to be very small. As a result, the heater wire 12 which is a heat switch and the winding frame 11 around which the switch portion 13 is wound do not need a housing for airtightly covering, and the switch operation is turned off (disconnected) by the heat generation of the heater wire 12 which is less. ) Can be realized with a simple configuration.

In the above description, the case where the permanent current switch 1E is provided in the superconducting device 10 has been described. However, similarly to the permanent current switch 1B, the permanent current switch 1E is not provided with the exhaust pump 8 and the refrigerant supply source 9. It can also be provided at 20.
[Sixth Embodiment]
A sixth embodiment of the present invention will be described with reference to FIG.

FIG. 8 is a cross-sectional view showing the internal configuration of the permanent current switch 1F according to the present embodiment. The permanent current switch 1F according to the present embodiment is a modification of the permanent current switch 1E according to the fifth embodiment. Therefore, it can be used in superconducting devices such as the superconducting device 10 according to the first embodiment and the superconducting device 20 according to the second embodiment, and it is possible to switch the formation and elimination of a closed circuit through which a permanent current flows. In the following description, as an example, a case where the permanent current switch 1F is provided in the superconducting device 10 will be described.

The configuration of the permanent current switch 1F will be described with reference to FIG.
As shown in FIG. 8, the permanent current switch 1F has substantially the same configuration as the winding frame 11 described in the above-described embodiment, has a through hole inside, and has a winding frame 11B vertically installed, and a heater wire. A support portion 17C for supporting the winding frame 11B (heat switch) around which the 12 and the switch portion 13 are wound is provided on the cooling member 7. Similar to the permanent current switch 1E, the permanent current switch 1F has a configuration in which the winding frame 11B is vertically placed on the mounting surface on which the permanent current switch 1F is mounted in the cooling member 7. .. That is, the winding frame 11B is arranged so that the axis of the winding frame 11B is substantially perpendicular to the mounting surface along the vertical direction, and is cooled via the support portion 17C, that is, across the support portion 17C. It is supported on the member 7. In FIG. 8, the winding frame 11B is vertically placed so that the flange F1 faces upward, but may be vertically placed so that the flange F2 faces upward.

The winding frame 11B is composed of a flange F1, a body portion M, and a flange F2, similarly to the winding frame 11 described in the above embodiment. The flange F1, the body portion M, and the flange F2 are the axial centers of the winding frame 11. It has a through hole that penetrates at the position. The winding frame 11B is made of a metal such as copper.
The support portion 17C is fixed to the flange (for example, the flange F2) below the vertically placed winding frame 11B (that is, the lower end side of the winding frame 11B), and is fixed on the cooling member 7 to wind the support portion 17C. The lower end side of the winding frame 11B is supported with respect to the cooling member 7 while securing a space S between the frame 11B and the cooling member 7. The support portion 17C has, for example, a cylindrical shape having a bottom surface having substantially the same size and shape as the disk-shaped flange F2, and is formed at the axial position of the winding frame 11B and the first support portion having a hollow inside. It is a member that has a cylindrical shape corresponding to the through hole and is integrated with a second support portion having a hollow inside, and is made of a metal such as stainless steel. The first support portion corresponds to the support portion 17B according to the fifth embodiment, and the hollow portion in the first support portion corresponds to the space S. The cylindrical second support portion is integrated with the first support portion so as to be substantially coaxial with the cylindrical first support portion, and the space between the hollow portion of the second support portion and the first support portion. S is communicating.

The second support portion of the support portion 17C has a length substantially the same as the length along the axial direction of the winding frame 11B, and is inserted into the through hole of the winding frame 11B from the flange F2 side. The second support portion is in close contact with the through hole of the winding frame 11B and supports the winding frame 11B together with the first support portion.
Here, as shown in FIG. 8, a through hole T1 and a conduit P1 described in the third embodiment are provided above the second support portion of the support portion 17C and connected to the exhaust pump 8 and the refrigerant supply source 9. Helium gas can be introduced and exhausted into the support portion 17C.

At this time, the through hole T1 and the conduit P1 are provided in a portion where the second support portion is exposed from the upper end surface of the flange F1. The heater wire 19 may be wound around the conduit P1 as in the third embodiment. Further, a temperature sensor 18 may be provided in the vicinity of the through hole T1 and the conduit P1 to measure the temperature of the helium gas immediately before or immediately after the inflow into the support portion 17C.
According to the permanent current switch 1F having the winding frame 11B and the supporting portion 17C having the above-described configuration, the amount of metal constituting the winding frame 11B is reduced by the amount of the through hole into which the second supporting portion of the supporting portion 17C is inserted. Therefore, the heat capacity of the winding frame 11B and, by extension, the permanent current switch 1F can be reduced. Further, the winding frame 11B having a small heat capacity easily rises in temperature due to the heat generated by the smaller heater wire 12, and is effectively cooled by the helium gas introduced into the second support portion inserted into the through hole. , The permanent current switch 1F capable of quickly switching between ON (connection) and OFF (disconnection) of the switch operation can be realized with a simple configuration.

In the above description, the case where the permanent current switch 1F is provided in the superconducting device 10 has been described. However, similarly to the permanent current switch 1B, the permanent current switch 1F is not provided with the exhaust pump 8 and the refrigerant supply source 9. It can also be provided at 20.
By the way, it should be considered that the embodiments disclosed this time are exemplary in all respects and are not restrictive. In particular, in the embodiments disclosed this time, matters not explicitly disclosed, for example, operating conditions, measurement conditions, various parameters, dimensions, weights, volumes of components, etc., deviate from the range normally implemented by those skilled in the art. A value that can be easily assumed by a person skilled in the art is adopted.

Specifically, in the first embodiment and the second embodiment described above, in the permanent current switches 1A and 1B, one flange F1 of the winding frame 11 is located at a position not overlapping with the body portion M in the longitudinal direction of the body portion M. Although it has been explained that the introduction port (through hole T) is provided along the above, the number of the through holes T is not limited to one. One through hole T may be provided in each of the flange F1 and the flange F2, or a plurality of through holes T may be provided in either the flange F1 and the flange F2. In this way, even when a plurality of through holes T are provided, gas and / or liquid refrigerant can be supplied into the permanent current switches 1A and 1B through the through holes T, and the permanent current switches 1A and 1A and The inside of 1B can be exhausted.

1A ~ 1F Permanent current switch 2 Storage container 3 Superconducting coil 4 Vacuum container 5 Refrigerator 6,7 Cooling member 8 Exhaust pump 9 Refrigerant supply source 10,20 Superconducting device 11,11A, 11B Winding frame 12,19 Heater wire 13 Switch part 14,14A housing (outer cylinder member)
15 Condensing part 16 Shielding shield 17, 17A to 17C Support part 18 Temperature sensor 50 Driving part 51 First stage stage 52 Second stage stage 53 Fins F1, F1a, F2 Flange H Liquid helium T, T1 Through hole P, P1, P2 Conduit M Body S Space V1, V2 Open / Close Valve

Claims (9)

Supports a winding frame for winding a coil, a heater wire wound in a coil shape around the winding frame, a superconducting wire wound in a coil shape so as to overlap the heater wire, and the winding frame. It is a permanent current switch that interrupts the superconducting circuit including the superconducting coil provided in the superconducting device cooled by the refrigerator.
It said persistent current switch is to have a feed port for supplying a gas and / or liquid coolant in the interior of the housing inside and outside and the housing communicates with the,
A permanent current switch , wherein the winding frame is supported on a cooling member of the refrigerator via a heat transfer limiting member that limits the amount of heat transfer. The permanent current switch according to claim 1, wherein the housing is configured to be thermally connected to the refrigerator. The permanent current switch according to claim 1 or 2, wherein the housing has a condensing portion that condenses a gaseous refrigerant existing inside the housing into a liquid. The heat transfer limiting member is said to form a space between the spool and the cooling member, the permanent current switch according to claim 1, characterized in that for supporting the reel on the cooling member .. The winding frame is vertically placed with respect to the cooling member with the axial direction facing up and down.
The permanent current switch according to claim 4 , wherein the heat transfer limiting member forms the space on the lower end side of the winding frame by supporting the upper end side or the lower end side of the winding frame. The permanent current switch according to claim 4 or 5 , wherein the heat transfer limiting member is configured to also serve as the housing. The permanent current switch according to any one of claims 1 to 6 is provided.
A superconducting device comprising a refrigerant supply source for supplying a refrigerant from the outside of the housing of the permanent current switch to the introduction port of the housing. The superconducting device according to claim 7 , further comprising a discharge means for discharging the refrigerant inside the housing from the introduction port of the housing to the outside of the housing. The superconducting device has a liquid helium that cools the superconducting coil.
The superconducting device according to claim 7 , wherein the refrigerant supply source is the liquid helium.