JPH10189324A - Permanent current switch - Google Patents
Permanent current switchInfo
- Publication number
- JPH10189324A JPH10189324A JP8292649A JP29264996A JPH10189324A JP H10189324 A JPH10189324 A JP H10189324A JP 8292649 A JP8292649 A JP 8292649A JP 29264996 A JP29264996 A JP 29264996A JP H10189324 A JPH10189324 A JP H10189324A
- Authority
- JP
- Japan
- Prior art keywords
- current switch
- permanent current
- cooling
- heater
- insulating material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Containers, Films, And Cooling For Superconductive Devices (AREA)
- Thermally Actuated Switches (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、冷凍機により冷却
され、永久電流モードで運転される超電導マグネットの
スイッチングを行う永久電流スイッチに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a permanent current switch for switching a superconducting magnet which is cooled by a refrigerator and operated in a permanent current mode.
【０００２】[0002]
【従来の技術】従来、永久電流モードで運転される超電
導マグネットおよび該超電導マグネットのスイッチング
を行う永久電流スイッチは、断熱された液体ヘリウム槽
等に浸漬されるなどして冷却されていた。しかし、液体
ヘリウムが高価であるとともに、槽構造乃至操作が複雑
であるため、構造乃至操作が簡単な、冷凍機による冷却
タイプに変わりつつある。2. Description of the Related Art Hitherto, a superconducting magnet operated in a permanent current mode and a permanent current switch for switching the superconducting magnet have been cooled by being immersed in an insulated liquid helium tank or the like. However, since liquid helium is expensive and the structure and operation of the tank are complicated, it is changing to a cooling type using a refrigerator, which has a simple structure and operation.
【０００３】図５に、冷凍機によって伝導冷却されるタ
イプの超電導マグネットの構成を示す。同図において、
超電導コイル５、永久電流スイッチ１は、真空容器１１
内に配置され、外界から断熱された状態となっている。
また、超電導コイル５と永久電流スイッチ１を包囲する
ように配置された輻射シールド１３は、真空容器からの
熱輻射を遮断する。さらに、超電導コイル５に電流を導
入する電流リード（銅リード１５）の一部に、酸化物超
電導リード１４を採用し、熱の侵入を軽減している。１
２は冷却源としての冷凍機であり、冷却ステージ１７、
冷却ブスバー（冷却板）１６を介して、超電導コイル５
や永久電流スイッチ１を伝導により冷却する。FIG. 5 shows a configuration of a superconducting magnet of a type which is conductively cooled by a refrigerator. In the figure,
The superconducting coil 5 and the permanent current switch 1 are
It is located inside and is insulated from the outside world.
Further, a radiation shield 13 arranged so as to surround superconducting coil 5 and persistent current switch 1 blocks thermal radiation from the vacuum vessel. Further, an oxide superconducting lead 14 is employed as a part of a current lead (copper lead 15) for introducing a current into the superconducting coil 5, thereby reducing heat penetration. 1
Reference numeral 2 denotes a refrigerator as a cooling source, and a cooling stage 17,
The superconducting coil 5 is connected via a cooling bus bar (cooling plate) 16.
And the permanent current switch 1 is cooled by conduction.
【０００４】一方、液体ヘリウムによって伝導冷却され
るタイプの超電導マグネットに使用されていた従来の永
久電流スイッチの構造を説明する。図６は、この従来の
永久電流スイッチの基本的な構造を示す断面図である。
図６において、６は巻枠であり、ヒータ線２および、ス
イッチ用超電導線３、断熱材４が同心円状に、巻枠６上
に捲回されている。On the other hand, the structure of a conventional permanent current switch used for a superconducting magnet of a type that is cooled by conduction with liquid helium will be described. FIG. 6 is a sectional view showing a basic structure of the conventional permanent current switch.
In FIG. 6, reference numeral 6 denotes a bobbin, in which a heater wire 2, a switch superconducting wire 3, and a heat insulating material 4 are concentrically wound around the bobbin 6.
【０００５】この永久電流スイッチを、冷凍機によって
伝導冷却されるタイプの超電導マグネットに適用し、超
電導コイル（マグネット）に流れる電流をスイッチング
する際の動作を図７により説明する。図７は、永久電流
スイッチと超電導コイル（マグネット）との結線図であ
る。同図において、５は永久電流スイッチのスイッチリ
ードに接続された超電導コイルであり、点線内で囲われ
た部分が永久電流スイッチ１である。２は超電導線巻線
部を加熱するためのヒータ、３はスイッチ用超電導線巻
線部、９は超電導コイルに電流を供給する主電源、１０
はヒータに加熱用の電流を供給するヒータ用電源であ
る。The operation of switching the current flowing through a superconducting coil (magnet) by applying this permanent current switch to a superconducting magnet of a type that is cooled by conduction by a refrigerator will be described with reference to FIG. FIG. 7 is a connection diagram of a permanent current switch and a superconducting coil (magnet). In the figure, reference numeral 5 denotes a superconducting coil connected to a switch lead of the permanent current switch, and a portion surrounded by a dotted line is a permanent current switch 1. 2 is a heater for heating the superconducting wire winding portion, 3 is a superconducting wire winding portion for a switch, 9 is a main power supply for supplying current to the superconducting coil, 10
Is a heater power supply for supplying a heating current to the heater.
【０００６】次に、永久電流モードで運転する際の励磁
手順を図７により説明する。主電源９から超電導コイル
５に電流を流す際に、ヒータ用電源１０からもヒータ２
に通電し、通電発熱したヒータ２により、スイッチ用超
電導線巻線部３を加熱する。加熱された超電導線巻線部
３は、常電導状態（オフ状態）に転移して、温度に応じ
た有限の抵抗値を持つ。そのため、主電源９から超電導
コイル５に電流を供給すると、永久電流スイッチ１はオ
フ状態となっているため、主電源９からの電流は、超電
導コイル５に流れ、その電流は増加することになる。Next, an excitation procedure when operating in the permanent current mode will be described with reference to FIG. When a current is supplied from the main power supply 9 to the superconducting coil 5, the heater 2 is also supplied from the heater power supply 10.
The superconducting wire winding 3 for a switch is heated by the heater 2 which is energized and generates heat. The heated superconducting wire winding unit 3 transitions to a normal conducting state (off state) and has a finite resistance value according to the temperature. Therefore, when a current is supplied from the main power supply 9 to the superconducting coil 5, the permanent current switch 1 is in the off state, so that the current from the main power supply 9 flows through the superconducting coil 5 and the current increases. .
【０００７】この超電導コイル５に流れる電流値が所定
の値になったところで、ヒータ２への通電（ヒータによ
る加熱）を停止すると、図示しない冷却部と熱的に短絡
している超電導線巻線部３の温度は低下して超電導状態
（オン状態）に転移する。そして、超電導線巻線部３が
オン状態に転移したあと、主電源９の電流を下げていく
と、超電導コイル５に流れる電流は一定のまま、主電源
９の電流低下分を補うように永久電流スイッチ１に電流
が流れ込む。つまり、電流は超電導コイル５と永久電流
スイッチの超電導線巻線部３の間をループして流れる。
その後、主電源９の電流を下げて超電導コイル５に供給
する電流をゼロにしても、超電導コイル５の電流は永久
電流スイッチ１を経由して流れ、所定の電流値を保った
ままとなる。このような状態を永久電流モードでの運転
という。When the value of the current flowing through the superconducting coil 5 reaches a predetermined value, when the power supply to the heater 2 (heating by the heater) is stopped, the superconducting wire winding thermally short-circuited with a cooling section (not shown). The temperature of the part 3 is lowered and transits to a superconducting state (ON state). When the current of the main power supply 9 is reduced after the superconducting wire winding section 3 is turned on, the current flowing through the superconducting coil 5 is kept constant while the current of the main power supply 9 is kept constant to compensate for the current decrease. A current flows into the current switch 1. That is, the current flows in a loop between the superconducting coil 5 and the superconducting wire winding portion 3 of the permanent current switch.
After that, even if the current of the main power supply 9 is reduced to zero the current supplied to the superconducting coil 5, the current of the superconducting coil 5 flows through the permanent current switch 1 and keeps a predetermined current value. Such a state is called operation in a permanent current mode.
【０００８】液体ヘリウム伝導冷却タイプの超電導マグ
ネットに使用されていた、永久電流スイッチを、冷凍機
によって伝導冷却されるタイプの超電導マグネットに適
用した場合、液体ヘリウムによる冷却される永久電流ス
イッチのヒータは、液体ヘリウムの冷却能力に見合っ
て、比較的大きい発熱能力を持っている。これに対し
て、前記冷凍機による冷却タイプの超電導マグネットシ
ステムでは、冷凍機の冷却能力が、液体ヘリウムより小
さいため、液体ヘリウムによる冷却タイプと同じ永久電
流スイッチ（ヒータ）を用いると、ヒータの熱負荷が大
きいことにより、システム全体を冷却する冷凍機の負担
が増し、システム全体の温度が上昇しやすくなる。When the permanent current switch used for the liquid-helium conduction cooling type superconducting magnet is applied to the superconducting magnet of the type that is conduction-cooled by a refrigerator, the heater of the liquid-helium-cooled permanent current switch is It has a relatively large heat generation capacity in proportion to the cooling capacity of liquid helium. On the other hand, in the superconducting magnet system of the cooling type using the refrigerator, the cooling capacity of the refrigerator is smaller than that of liquid helium. Due to the large load, the load on the refrigerator that cools the entire system increases, and the temperature of the entire system easily rises.
【０００９】即ち、超電導線巻線部３は冷却部と熱的に
短絡しているため、永久電流スイッチ１をオフ状態とす
るために、ヒータ２により、超電導線巻線部３を加熱し
た場合、低温ステージに熱が逃げやすく、ヒータ２によ
る超電導線巻線部３の加熱時に、低温ステージへの熱侵
入が生じて、システム全体の温度が上昇し、超電導コイ
ルの温度も上昇して、超電導コイルがクエンチ（常電導
転移）しやすくなるという問題点がある。That is, since the superconducting wire winding portion 3 is thermally short-circuited with the cooling portion, the heater 2 heats the superconducting wire winding portion 3 to turn off the permanent current switch 1. The heat easily escapes to the low-temperature stage, and when the superconducting wire winding section 3 is heated by the heater 2, heat enters the low-temperature stage, so that the temperature of the entire system increases and the temperature of the superconducting coil also increases. There is a problem that the coil is easily quenched (normal conduction transition).
【００１０】この問題を解決するため、従来から特開平
8-138928号公報や特表平8-505493公報などに示すような
対策が採られている。特開平8-138928号公報では、永久
電流スイッチと冷凍機冷却ステージとを熱的に短絡およ
び切り離しするための機構を備えている。この機構は、
ヒーターが永久電流スイッチ部を加熱している時には、
冷凍機冷却ステージと永久電流スイッチとの熱的な接続
を切り離し、ヒーターが永久電流スイッチ部を加熱して
いない時には、冷凍機冷却ステージと永久電流スイッチ
を熱的に短絡する。このことにより、永久電流スイッチ
をオフする際に、ヒーターで永久電流スイッチ部の加熱
を行っても熱が低温ステージに入りにくいものとし、超
電導コイルの温度上昇を防止してクエンチの発生を抑制
している。In order to solve this problem, Japanese Patent Laid-Open Publication No.
The countermeasures shown in JP-A-8-138928 and JP-T-Hei 8-505493 have been adopted. JP-A-8-138928 has a mechanism for thermally short-circuiting and separating a permanent current switch and a refrigerator cooling stage. This mechanism is
When the heater is heating the permanent current switch,
The thermal connection between the refrigerator cooling stage and the permanent current switch is disconnected, and when the heater is not heating the permanent current switch section, the refrigerator cooling stage and the permanent current switch are thermally short-circuited. This makes it difficult for the heat to enter the low-temperature stage even when the permanent current switch is heated by the heater when the permanent current switch is turned off, prevents the temperature rise of the superconducting coil, and suppresses the occurrence of quench. ing.
【００１１】また、特表平8-505493号公報では、永久電
流スイッチと冷凍機とを結ぶ冷却ブスバーに、温度が上
昇するにつれて熱伝導率が低下する材料を用いている。
これにより、永久電流スイッチと冷凍機冷却ステージと
を熱的に短絡しにくくし、前記特開平8-138928号公報と
同様に、超電導コイルの温度上昇を防止してクエンチの
発生を抑制している。In Japanese Patent Publication No. 8-505493, a cooling busbar connecting a permanent current switch and a refrigerator is made of a material whose thermal conductivity decreases as the temperature rises.
This makes it difficult to thermally short-circuit the permanent current switch and the refrigerator cooling stage, and, similarly to the above-mentioned JP-A-8-138928, prevents the temperature rise of the superconducting coil and suppresses the occurrence of quench. .
【００１２】[0012]
【発明が解決しようとする課題】しかし、これら従来技
術、特に特開平8-138928号公報の永久電流スイッチは、
冷凍機冷却ステージと熱的に短絡および切り離しするた
めの機構を備えているため、構造が複雑となり、製作に
時間とコストがかかるという問題点があった。また、長
期間使用していると、熱的に短絡したときの熱接触が劣
化し、安定して作動しないことがあるといった問題点も
あった。However, these prior arts, especially the permanent current switch disclosed in Japanese Patent Application Laid-Open No. H8-138928,
Since a mechanism for thermally short-circuiting and separating from the refrigerator cooling stage is provided, the structure becomes complicated, and there is a problem that the production takes time and costs. In addition, when used for a long period of time, there is a problem that thermal contact when a thermal short circuit occurs is deteriorated and the device may not operate stably.
【００１３】更に、構造が比較的単純である特表平8-50
5493号公報においても、温度が上昇するにつれて低下す
る熱伝導率を有する材料は、稀少であり、かつ高価であ
るという問題点がある。[0013] Furthermore, Japanese Patent Application Laid-Open No. Hei 8-50, whose structure is relatively simple.
Also in Japanese Patent No. 5493, there is a problem that a material having a thermal conductivity that decreases as the temperature rises is rare and expensive.
【００１４】したがって、本発明の目的は、冷凍機冷却
ステージと安定して熱的に切り離すことができるととも
に、構造が単純で、かつ短時間、低コストで作成できる
機構を有する永久電流スイッチを提供することである。Accordingly, an object of the present invention is to provide a permanent current switch having a mechanism that can be stably thermally separated from a refrigerator cooling stage, has a simple structure, and can be manufactured in a short time and at low cost. It is to be.
【００１５】[0015]
【課題を解決するための手段】この目的のため、本発明
の要旨は、超電導コイルとともに真空容器内に配置さ
れ、かつ電源に超電導コイルと並列に接続されるととも
に、冷凍機によって伝導冷却されて前記超電導コイルに
流れる電流のスイッチングを行う永久電流スイッチの構
造を、スイッチ用超電導線が巻回された巻き線部と、巻
き線部を加熱するヒータと、巻き線部に当接する断熱材
とを含むとともに、巻き線部を断熱材を介して伝導冷却
する冷却部材を配置した構造とすることである。SUMMARY OF THE INVENTION For this purpose, the gist of the present invention is to arrange a superconducting coil together with a superconducting coil in a vacuum vessel, connect the power supply in parallel with the superconducting coil, and conduct conduction cooling by a refrigerator. The structure of the permanent current switch that performs switching of the current flowing through the superconducting coil, a winding portion around which the switching superconducting wire is wound, a heater that heats the winding portion, and a heat insulating material that contacts the winding portion. In addition, a cooling member that conducts conductive cooling of the winding portion via a heat insulating material is provided.
【００１６】前記した通り、液体ヘリウム冷却タイプの
永久電流スイッチを、そのまま、冷凍機による冷却タイ
プの永久電流スイッチに適用しようとすると、永久電流
スイッチ内のヒータの発熱量が大きすぎ、超電導コイル
自体の温度上昇を引き起こし、超電導コイルがクエンチ
（常電導転移）することとなる。このため、前記従来技
術では、この事態を避けるために、ヒータの過剰な発熱
を超電導コイルに伝えないようにするための工夫をしよ
うとしていた。この場合、ヒータの発熱量自体を下げ
て、ヒータの過剰な発熱を超電導コイルに伝えないよう
にすることも考えられるが、これでは、永久電流スイッ
チの常温状態（オフ状態）の移行に時間を要することに
なるからである。As described above, if the liquid helium cooling type permanent current switch is applied to a cooling type permanent current switch using a refrigerator as it is, the heating value of the heater in the permanent current switch is too large, and the superconducting coil itself is not used. , Causing the superconducting coil to quench (normal conduction transition). For this reason, in the above-mentioned prior art, in order to avoid this situation, an attempt was made to prevent excessive heat generation of the heater from being transmitted to the superconducting coil. In this case, it is conceivable to reduce the amount of heat generated by the heater so that excessive heat generated by the heater is not transmitted to the superconducting coil. However, in this case, it takes time for the transition of the permanent current switch to the normal temperature state (off state). It is necessary.
【００１７】しかし、本発明では、永久電流スイッチの
超電導線巻き線部に、適切な熱通過率を有する断熱材を
当接させるとともに、超電導線巻き線部をこの断熱材を
介して伝導冷却する冷却部材を配置すれば、前記従来技
術のような、特別に複雑乃至高価な構造を有さずとも、
冷凍機冷却ステージと安定して熱的に切り離すことがで
き、しかも、永久電流スイッチの伝導冷却能力を一段と
高め、スイッチ用超電導線の超電導状態（オン状態）へ
の転移などを早めるのが可能となることを知見したもの
である。However, according to the present invention, a heat insulating material having an appropriate heat transmittance is brought into contact with the superconducting wire winding portion of the permanent current switch, and the superconducting wire winding portion is conductively cooled through the heat insulating material. If the cooling member is arranged, even if it does not have a specially complicated or expensive structure as in the prior art,
It can be thermally separated from the refrigerator cooling stage stably, and the conduction cooling capacity of the permanent current switch can be further increased, and the transition of the superconducting wire for the switch to the superconducting state (ON state) can be accelerated. It was found that it became.
【００１８】したがって、本発明では、冷却部材や熱通
過率を考慮した断熱材を除いて、従来の液体ヘリウムで
使われていた永久電流スイッチの基本構造を、そのまま
使用することが可能である。このため、本発明永久電流
スイッチでは、前記従来の永久電流スイッチ同様、ヒー
タおよび超電導線、断熱材、冷却部材は、永久電流スイ
ッチ自体のコンパクト化や冷却乃至断熱効率上、各々同
心円状に配置されていることが好ましい。Therefore, in the present invention, it is possible to use the basic structure of the permanent current switch used for the conventional liquid helium as it is, except for the cooling member and the heat insulating material in consideration of the heat transmittance. For this reason, in the permanent current switch of the present invention, similarly to the conventional permanent current switch, the heater, the superconducting wire, the heat insulating material, and the cooling member are arranged concentrically in terms of the compactness of the permanent current switch itself and the cooling or heat insulating efficiency. Is preferred.
【００１９】なお、従来の液体ヘリウムで使われていた
永久電流スイッチでも、永久電流スイッチが固定される
図５に示す冷却ブスバーと、図６に示す巻枠６の底部を
介して、伝導冷却されており、本発明でもこの点は同じ
である。しかし、本発明では、更にこれに加えて、巻き
線部に当接する断熱材の外側（図１の場合）乃至内側
（図２の場合）に、超電導線巻き線部乃至断熱材周囲を
囲う形で冷却部材を配置し、伝導冷却能力を一段と高
め、スイッチ用超電導線の超電導状態（オン状態）への
転移を早めている。In the conventional permanent current switch used for liquid helium, conduction cooling is performed via the cooling bus bar shown in FIG. 5 to which the permanent current switch is fixed and the bottom of the bobbin 6 shown in FIG. This is the same in the present invention. However, in the present invention, in addition to the above, a shape surrounding the periphery of the superconducting wire winding portion or the heat insulating material is provided outside (in the case of FIG. 1) or inside (in the case of FIG. 2) of the heat insulating material in contact with the winding portion. The cooling member is arranged to further increase the conduction cooling capacity, and hasten the transition of the superconducting wire for the switch to the superconducting state (ON state).
【００２０】また、冷却部材は、永久電流スイッチを冷
凍機によって伝導冷却するため、銅、またはアルミ等の
良熱伝導金属材料からなり、後述するごとく、超電導線
巻き線部を囲む乃至包囲する形で伝導冷却することが望
ましい。The cooling member is made of a good heat conducting metal material such as copper or aluminum for conducting and cooling the permanent current switch by a refrigerator, and surrounds or surrounds the superconducting wire winding portion as described later. It is desirable to conduct conduction cooling.
【００２１】更に、断熱材の熱通過率は、図１、２のよ
うに、ヒータおよび超電導線、断熱材、冷却部材が各々
同心円状に配置されている場合、冷凍機の３〜８K にお
ける冷却能力をαW としたとき、断熱材の同心円の径方
向の熱通過率が最大で５０αW/(m2 ・K)以下であること
が望ましい。熱通過率が前記５０αW/(m2 ・K)を超える
と、ヒータによる加熱効率が悪くなり、超電導線の常温
状態（オフ状態）への転移が遅くなるとともに、低温ス
テージに熱が逃げやすく、ヒータの容量を大きくする必
要があるばかりか、ヒータによる加熱時に、低温ステー
ジへの熱侵入が生じて、システム全体の温度が上昇し、
超電導コイルの温度も上昇して、超電導コイルがクエン
チ（常電導転移）しやすくなるという問題点がある。Further, as shown in FIGS. 1 and 2, when the heater and the superconducting wire, the heat insulating material, and the cooling member are arranged concentrically, as shown in FIGS. Assuming that the capacity is αW, it is desirable that the heat transfer coefficient in the radial direction of the concentric circle of the heat insulating material is 50 αW / (m 2 · K) or less at maximum. When the heat transmission rate exceeds the above 50αW / (m 2 · K), the heating efficiency by the heater deteriorates, the transition of the superconducting wire to the normal temperature state (off state) becomes slow, and the heat easily escapes to the low temperature stage, In addition to the need to increase the capacity of the heater, when the heater heats up, heat enters the low-temperature stage, increasing the temperature of the entire system,
There is a problem that the temperature of the superconducting coil also increases, and the superconducting coil is easily quenched (normal conduction transition).
【００２２】また断熱材の最小熱通過率は、超電導線の
冷却効率の点から決まり、小さすぎると、超電導線の冷
却効率が悪くなり、超電導状態（オン状態）への転移が
遅くなるで、０．５αW/(m2 ・K)以上であることがより
望ましい。Further, the minimum heat transmission rate of the heat insulating material is determined in terms of the cooling efficiency of the superconducting wire. If it is too small, the cooling efficiency of the superconducting wire becomes poor, and the transition to the superconducting state (on state) becomes slow. More preferably, it is 0.5αW / (m 2 · K) or more.
【００２３】また、この熱通過率を確保するため、断熱
材の材質としては、パテ、テフロン、ナイロン、ＦＲ
Ｐ、ベークライト、エポキシ樹脂、ワックス、またはこ
れらの複合材の内から選択されることが望ましい。In order to secure this heat transmission rate, the material of the heat insulating material is putty, Teflon, nylon, FR, or the like.
Desirably, it is selected from P, bakelite, epoxy resin, wax, or a composite material thereof.
【００２４】[0024]
【発明の実施の形態】永久電流スイッチの１実施態様
を、図１に示す。同図において、永久電流スイッチ１の
構造は、図１に示した従来の永久電流スイッチ構造と同
様であり、この永久電流スイッチ１を冷却ホルダー７の
中に装入し、図１における永久電流スイッチの側面と底
部を、冷却ホルダー７の胴部８とフランジ部９により囲
む形とする。このフランジ部９は、図５の冷却ブスバー
１６上に取り付けられ、冷凍機からの伝導により、図５
の冷却ブスバー１６を介し、かつ冷却ホルダー７の胴部
８とフランジ部９を介して、永久電流スイッチ１が冷却
される。DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a permanent current switch is shown in FIG. 1, the structure of the permanent current switch 1 is the same as that of the conventional permanent current switch shown in FIG. 1, and the permanent current switch 1 is inserted into the cooling holder 7, and the permanent current switch shown in FIG. Of the cooling holder 7 are surrounded by the body 8 and the flange 9. This flange portion 9 is mounted on the cooling bus bar 16 of FIG.
The permanent current switch 1 is cooled via the cooling bus bar 16 and the body 8 and the flange 9 of the cooling holder 7.
【００２５】この永久電流スイッチ１を、冷却ホルダー
７に装入する実施態様では、永久電流スイッチ１と冷却
ホルダー７の内面とに、必然的に隙間が発生し、この隙
間は真空であるので（雰囲気は真空容器内で真空に保持
されているので）、隙間があると、熱の伝導が無くな
り、冷却ホルダー７の冷却効果が無くなる。したがっ
て、該隙間には、アピエゾングリースを挿入し、隙間を
作らないようにした。In the embodiment in which the permanent current switch 1 is inserted into the cooling holder 7, a gap is inevitably formed between the permanent current switch 1 and the inner surface of the cooling holder 7, and this gap is a vacuum. Since the atmosphere is kept in a vacuum in the vacuum vessel), if there is a gap, heat conduction is lost, and the cooling effect of the cooling holder 7 is lost. Therefore, Apiezon grease was inserted into the gap so that no gap was formed.
【００２６】[0026]
【実施例】図１に示す永久電流スイッチ１、図５に示す
超電導マグネット装置を用いて、永久電流モードでの運
転による励磁試験を行った。励磁試験は、永久電流スイ
ッチに、断熱材、冷却部材、形状、常電導抵抗値等が異
なる５種類を用い、この永久電流スイッチの条件を変え
た以外は、すべて同じシステム構成乃至条件として行っ
た。EXAMPLE An excitation test was performed by operating in the permanent current mode using the permanent current switch 1 shown in FIG. 1 and the superconducting magnet device shown in FIG. Excitation tests were performed with the same system configuration and conditions, except that the permanent current switch used five types having different heat insulating materials, cooling members, shapes, and normal conduction resistance values, and the conditions of the permanent current switch were changed. .
【００２７】〔実施例１〕超電導コイルの仕様は、イン
ダクタンス；59.6H 、定格磁場；5T、定格電流；52.5A
、外径；280mm 、ボア内径；150mm 、巻長さ；295mm
、使用線材；マルチフィラメントNbTiとした。また、
冷凍機の仕様は、最低到達温度；3K、冷凍能力；1.0W/
(4.2K時) とした。永久電流スイッチは、冷却部材を銅
製の冷却ホルダー７とし、断熱材は厚さ10.6mmのパテを
使用し、熱通過率；5.3W/(m2・K)、常電導抵抗値； 5
Ω、ヒータ抵抗は、抵抗値；100 Ω、外径；12mm、長
さ；38mmのものを用いた。[Example 1] The specifications of the superconducting coil are as follows: inductance: 59.6H, rated magnetic field: 5T, rated current: 52.5A
, Outer diameter: 280mm, Bore inner diameter: 150mm, Roll length: 295mm
, Wire used: multifilament NbTi. Also,
Refrigerator specifications are: minimum temperature: 3K, refrigeration capacity: 1.0W /
(At 4.2K). The permanent current switch uses a cooling member 7 made of copper as a cooling member, uses a putty having a thickness of 10.6 mm as a heat insulating material, a heat transmission rate: 5.3 W / (m2 · K), and a normal conduction resistance value;
Ω, heater resistance, resistance value: 100 Ω, outer diameter: 12 mm, length: 38 mm were used.
【００２８】システムを冷凍機により冷却し、永久電流
スイッチ、超電導コイルともに、温度を４Ｋの状態とし
た。次に、永久電流スイッチのヒーター用電源を入れ、
ヒーターに20mAを通電した。約1 分後、永久電流スイッ
チの温度は10K となり、常電導状態になることが確認で
きた。このとき、超電導コイルは、約4Kのままであり、
冷却ステージと安定して熱的に切り離せていることが確
認できた。The system was cooled by a refrigerator, and the temperature of both the permanent current switch and the superconducting coil was kept at 4K. Next, turn on the heater power of the permanent current switch,
20 mA was supplied to the heater. After about one minute, the temperature of the permanent current switch reached 10K, confirming that it was in the normal conduction state. At this time, the superconducting coil remains at about 4K,
It was confirmed that it was thermally separated stably from the cooling stage.
【００２９】続いて、0.020A/ 秒のスピードで、電源電
流Ｃを定格電流まで上げて、超電導コイルの励磁を行っ
た。この時の、超電導コイルと永久電流スイッチの温度
変化を、図３に示す。図３から、永久電流スイッチ温度
Ｂは約30K まで、超電導コイル温度Ａは5.2Kまで温度上
昇していることが分かる。しかし、励磁中、永久電流ス
イッチへの分流による発熱は、370mW と見積もられる
が、クエンチを起こすことなく、発生磁場Ｄは定格の５
T （テスラ）まで励磁することが可能であった。このこ
とから、本発明永久電流スイッチは十分な断熱機構を有
していることがわかる。励磁終了後ヒータを切り、約13
分後に、永久電流スイッチがオン状態に転移し、永久電
流モードに移行したことが確認できた。Subsequently, the power supply current C was increased to the rated current at a speed of 0.020 A / sec to excite the superconducting coil. FIG. 3 shows temperature changes of the superconducting coil and the permanent current switch at this time. From FIG. 3, it can be seen that the permanent current switch temperature B has increased to about 30K and the superconducting coil temperature A has increased to 5.2K. However, during the excitation, the heat generated by the shunt to the permanent current switch is estimated to be 370 mW.
It was possible to excite up to T (Tesla). This indicates that the permanent current switch of the present invention has a sufficient heat insulating mechanism. After excitation, turn off the heater and
Minutes later, it was confirmed that the permanent current switch transited to the ON state and transited to the permanent current mode.
【００３０】〔実施例２〕次に、永久電流スイッチの常
電導抵抗値を40Ω、ヒータ外径を18mmとした以外は、実
施例１と同じ条件にて、同様の励磁試験を行った。シス
テムを冷凍機により冷却し、永久電流スイッチ、超電導
コイルともに温度は４Ｋの状態とした。その後、ヒータ
ーに20mAを通電した約1 分後には、永久電流スイッチの
温度は10K となり、常電導状態になることが確認でき
た。このとき、超電導コイルは、4Kのままであり、冷却
ステージと安定して熱的に切り離せていることが確認で
きた。Example 2 Next, a similar excitation test was performed under the same conditions as in Example 1, except that the normal current resistance of the permanent current switch was set to 40Ω and the outer diameter of the heater was set to 18 mm. The system was cooled by a refrigerator, and the temperature of both the permanent current switch and the superconducting coil was kept at 4K. Then, about 1 minute after the heater was supplied with 20 mA, it was confirmed that the temperature of the permanent current switch was 10 K and the state was normal conduction. At this time, it was confirmed that the superconducting coil remained at 4K and was thermally separated stably from the cooling stage.
【００３１】続いて、実施例１より速い0.049A/ 秒のス
ピードで、電源電流Ｃを定格電流まで上げて、超電導コ
イルの励磁を行った。この時の、超電導コイルと永久電
流スイッチの温度変化を、図４に示す。図４から分かる
通り、永久電流スイッチの温度Ｂは、約19K まで上昇し
ている。しかし、超電導コイル温度Ａは5.2Kまでしか温
度上昇せず、クエンチを起こすことなく、発生磁場Ｄは
定格の５T （テスラ）まで励磁することが可能であっ
た。励磁終了後ヒータを切り、約7 分後に、永久電流ス
イッチがオン状態に転移し、永久電流モードに移行した
ことが確認できた。Subsequently, the power supply current C was increased to the rated current at a speed of 0.049 A / sec, which was higher than that in Example 1, and the superconducting coil was excited. FIG. 4 shows temperature changes of the superconducting coil and the permanent current switch at this time. As can be seen from FIG. 4, the temperature B of the persistent current switch has increased to about 19K. However, the superconducting coil temperature A increased only to 5.2 K, and the generated magnetic field D could be excited to the rated 5T (tesla) without causing quench. After the excitation was completed, the heater was turned off. After about 7 minutes, it was confirmed that the permanent current switch was turned on and the mode was changed to the permanent current mode.
【００３２】〔実施例３〕次に、永久電流スイッチの、
断熱材の厚さを0.7mm 、熱通過率；53W/(m2 ・K)、常電
導抵抗値を40Ω、ヒータ外径を7.6mm とした以外は、実
施例１と同じ条件にて、同様の励磁試験を行った。シス
テムを冷凍機により冷却し、永久電流スイッチ、超電導
コイルともに温度は４Ｋの状態とした。その後、ヒータ
ーに65mAを通電した約30秒後には、永久電流スイッチの
温度は10K となり、常電導状態になることが確認でき
た。このとき、超電導コイルは、4.4Kであった。[Embodiment 3] Next, the permanent current switch
The same conditions as in Example 1 were used except that the thickness of the heat insulating material was 0.7 mm, the heat transmission rate was 53 W / (m2 · K), the normal conduction resistance was 40 Ω, and the outer diameter of the heater was 7.6 mm. An excitation test was performed. The system was cooled by a refrigerator, and the temperature of both the permanent current switch and the superconducting coil was kept at 4K. Then, about 30 seconds after the heater was supplied with 65 mA, it was confirmed that the temperature of the permanent current switch was 10 K and the state was normal conduction. At this time, the superconducting coil was 4.4K.
【００３３】続いて、実施例１と同じ0.049A/ 秒のスピ
ードで、超電導コイルの励磁を行ったが、このときの、
超電導コイルは5.6Kまで温度上昇し、クエンチを起こし
た。これは、永久電流スイッチをオフ状態にするのに、
約420mW のヒータ負荷が必要であったため、システム全
体の温度が上昇したことがクエンチの原因である。この
場合には、断熱材の熱通過率が高すぎるのが問題であ
り、断熱材の熱通過率をもっと下げる、或いは断熱材の
熱通過率はそのままにして、超電導コイルの励磁をもっ
と遅いスピードで行えば、クエンチを防止することがで
きる。Subsequently, the superconducting coil was excited at the same speed of 0.049 A / sec as in the first embodiment.
The temperature of the superconducting coil rose to 5.6K, causing quench. This turns off the persistent current switch,
A quench was caused by an increase in the temperature of the entire system, which required a heater load of about 420 mW. In this case, the problem is that the heat transfer rate of the heat insulating material is too high, and the heat transfer rate of the heat insulating material is further reduced, or the heat transfer rate of the heat insulating material is kept as it is, and the excitation of the superconducting coil is performed at a lower speed. Quench can be prevented.
【００３４】〔実施例４〕次に、永久電流スイッチは、
銅製の冷却ホルダーとし、断熱材は厚さ31mmのテフロン
を使用し、熱通過率；0.48W/(m2 ・K)、常電導抵抗値；
40Ω、ヒータ抵抗は、抵抗値；100 Ω、外径；39mm、長
さ；38mmのものを用い、実施例１と同じ条件にて、同様
の励磁試験を行った。システムを冷凍機により冷却し、
永久電流スイッチ、超電導コイルともに温度は４Ｋの状
態とした。その後、ヒーターに2mA を通電した約1 分後
には、永久電流スイッチの温度は10K となり、常電導状
態になることが確認できた。このとき、超電導コイル
は、4.0Kであった。Embodiment 4 Next, a permanent current switch is
A cooling holder made of copper, using a Teflon with a thickness of 31 mm for the heat insulating material, a heat transmission rate: 0.48 W / (m2 · K), a normal conduction resistance value;
The same excitation test was performed under the same conditions as in Example 1 using a heater resistance of 40 Ω, a resistance value of 100 Ω, an outer diameter of 39 mm, and a length of 38 mm. The system is cooled by a refrigerator,
The temperature of both the permanent current switch and the superconducting coil was 4K. Then, about 1 minute after the 2 mA was supplied to the heater, the temperature of the permanent current switch reached 10 K, confirming that it was in the normal conduction state. At this time, the superconducting coil was at 4.0K.
【００３５】続いて、実施例２と同じ0.049A/ 秒のスピ
ードで、超電導コイルの励磁を行った。この結果、永久
電流スイッチの温度は、約18K まで上昇した。しかし、
超電導コイルは5.2Kまでしか温度上昇せず、クエンチを
起こすことなく定格の５テスラまで励磁することが可能
であった。励磁終了後ヒータを切り３時間経過後、永久
電流スイッチがオン状態に転移し、永久電流モードに移
行した。この例の場合は、断熱材の熱通過率が小さす
ぎ、永久電流スイッチのオン状態への転移に長い時間を
要している。したがって、断熱材の熱通過率を高くすれ
ば時間短縮が可能である。Subsequently, the superconducting coil was excited at the same speed of 0.049 A / sec as in Example 2. As a result, the temperature of the persistent current switch rose to about 18K. But,
The temperature of the superconducting coil rose only to 5.2K, and it was possible to excite it to the rated 5 Tesla without causing quench. After completion of the excitation, the heater was turned off, and after elapse of 3 hours, the permanent current switch was turned on, and the mode was shifted to the permanent current mode. In this case, the heat transfer rate of the heat insulating material is too small, and it takes a long time to transition the permanent current switch to the ON state. Therefore, the time can be reduced by increasing the heat transmission rate of the heat insulating material.
【００３６】〔実施例５〕次に、図２に示す、別の実施
態様の永久電流スイッチを用いて、実施例１と同様の励
磁試験を行った。図５の永久電流スイッチ１では、冷却
部材１８を、永久電流スイッチ１の内側に持ってきてお
り、かつ冷却部材１８が、超電導線３などの巻枠を兼用
している点が前記実施態様と異なる点である。この場
合、断熱材４、超電導線３、ヒータ線２が、冷却部材１
８側から順に、同心円状に、冷却部材１８上に捲回され
ている。Example 5 Next, an excitation test similar to that of Example 1 was performed using a permanent current switch of another embodiment shown in FIG. In the permanent current switch 1 of FIG. 5, the cooling member 18 is brought inside the permanent current switch 1, and the cooling member 18 also serves as a winding frame of the superconducting wire 3 or the like. It is different. In this case, the heat insulating material 4, the superconducting wire 3, and the heater wire 2
It is wound on the cooling member 18 concentrically in order from the 8 side.
【００３７】図２の永久電流スイッチとして、アルミ製
の冷却部材とし、断熱材は厚さ3mmのパテを使用し、熱
通過率；5.3W/(m2・K)、常電導抵抗値；40Ω、ヒータ抵
抗は、抵抗値；100 Ω、外径；5.3mm 、長さ；38mmのも
のを用い、実施例１と同じ条件にて、同様の励磁試験を
行った。システムを冷凍機により冷却し、永久電流スイ
ッチ、超電導コイルともに温度は４Ｋの状態とした。そ
の後、ヒーターに20mAを通電した約1 分後には、永久電
流スイッチの温度は約10K となり、常電導状態になるこ
とが確認できた。このとき、超電導コイルは、4.0Kであ
った。As a permanent current switch shown in FIG. 2, a cooling member made of aluminum was used, a putty having a thickness of 3 mm was used as a heat insulating material, a heat transmission rate: 5.3 W / (m 2 · K), a normal conduction resistance value: 40 Ω, The same excitation test was performed under the same conditions as in Example 1 by using a heater resistor having a resistance value of 100 Ω, an outer diameter of 5.3 mm, and a length of 38 mm. The system was cooled by a refrigerator, and the temperature of both the permanent current switch and the superconducting coil was kept at 4K. Then, about 1 minute after applying 20 mA to the heater, the temperature of the permanent current switch became about 10 K, confirming that the heater was in the normal conduction state. At this time, the superconducting coil was at 4.0K.
【００３８】続いて、実施例２と同じ0.049A/ 秒のスピ
ードで、超電導コイルの励磁を行った。永久電流スイッ
チの温度は、約19K まで上昇した。しかし、超電導コイ
ルは5.2Kまでしか温度上昇せず、クエンチを起こすこと
なく定格の５T(テスラ) まで励磁することが可能であっ
た。励磁終了後ヒータを切り、約7 分後に、永久電流ス
イッチがオン状態に転移し、永久電流モードに移行した
ことが確認できた。Subsequently, the superconducting coil was excited at the same speed of 0.049 A / sec as in Example 2. The temperature of the persistent current switch rose to about 19K. However, the temperature of the superconducting coil rose only to 5.2K, and it was possible to excite it to the rated 5T (tesla) without causing quench. After the excitation was completed, the heater was turned off. After about 7 minutes, it was confirmed that the permanent current switch was turned on and the mode was changed to the permanent current mode.
【００３９】[0039]
【発明の効果】以上説明した通り、本発明では、冷凍機
によって冷却される永久電流スイッチにおいて、従来の
永久電流スイッチに比して、断熱材の熱通過率を特定
し、冷却部を設けるという簡単な構造により、短時間、
低コストで作成でき、かつ安定して作動る永久電流スイ
ッチを提供することができる。As described above, according to the present invention, in the permanent current switch cooled by the refrigerator, the heat transmission rate of the heat insulating material is specified and the cooling unit is provided as compared with the conventional permanent current switch. Simple structure, short time,
A permanent current switch that can be manufactured at low cost and operates stably can be provided.
【図１】本発明の永久電流スイッチの１実施態様を示
す、斜視図である。FIG. 1 is a perspective view showing one embodiment of a permanent current switch of the present invention.
【図２】本発明の永久電流スイッチの他の実施態様を示
す、断面図である。FIG. 2 is a sectional view showing another embodiment of the permanent current switch of the present invention.
【図３】本発明の１実施例を示し、超電導コイルの励磁
を行った時の、超電導コイルと永久電流スイッチの温度
変化を示す説明図である。FIG. 3 is an explanatory diagram showing a temperature change of the superconducting coil and the permanent current switch when the superconducting coil is excited according to the embodiment of the present invention.
【図４】本発明の他の実施例を示し、超電導コイルの励
磁を行った時の、超電導コイルと永久電流スイッチの温
度変化を示す説明図である。FIG. 4 shows another embodiment of the present invention, and is an explanatory diagram showing temperature changes of the superconducting coil and the permanent current switch when the superconducting coil is excited.
【図５】冷凍機冷却型超電導マグネットシステムの概略
を示す、断面図である。FIG. 5 is a sectional view schematically showing a refrigerator-cooled superconducting magnet system.
【図６】従来の液体ヘリウム伝導冷却タイプの永久電流
スイッチの実施態様を示す、断面図である。FIG. 6 is a sectional view showing an embodiment of a conventional liquid helium conduction cooling type permanent current switch.
【図７】従来の永久電流スイッチの動作を示す、結線図
である。FIG. 7 is a connection diagram showing the operation of a conventional permanent current switch.
１：永久電流スイッチ ２：ヒータ線 ３：超電導線 ４：断熱材 ５：超電導マグネット ６：巻枠 ７：冷却部材 ８：胴部 ９：主電源 10：ヒータ用電源 11：真空容器 12：冷凍機 13：輻射シールド 14：酸化物超電導リード 15：銅リード 16：冷却ブスバー 17：冷凍機冷却ステージ 18：冷却部材 19：フランジ 20：超電導マグネットシステム 1: Permanent current switch 2: Heater wire 3: Superconducting wire 4: Heat insulation material 5: Superconducting magnet 6: Reel 7: Cooling member 8: Body 9: Main power supply 10: Heater power supply 11: Vacuum container 12: Refrigerator 13: Radiation shield 14: Oxide superconducting lead 15: Copper lead 16: Cooling bus bar 17: Refrigerator cooling stage 18: Cooling member 19: Flange 20: Superconducting magnet system
───────────────────────────────────────────────────── フロントページの続き (72)発明者 林 征治 神戸市西区高塚台１丁目５−５ 株式会社 神戸製鋼所神戸総合技術研究所内 ────────────────────────────────────────────────── ─── Continued on front page (72) Inventor Seiji Hayashi 1-5-5 Takatsukadai, Nishi-ku, Kobe Kobe Steel, Ltd. Kobe Research Institute
Claims (6)
イルと並列に接続され、前記冷凍機によって伝導冷却さ
れて前記超電導コイルに流れる電流のスイッチングを行
う永久電流スイッチにおいて、スイッチ用超電導線が巻
回された巻き線部と、該巻き線部を加熱するヒータと、
巻き線部に当接する断熱材とを含むとともに、巻き線部
を断熱材を介して伝導冷却する冷却部材を配置したこと
を特徴とする永久電流スイッチ。1. A permanent current switch connected in parallel with a superconducting coil conductively cooled by a refrigerator and switching a current flowing through the superconducting coil after conduction cooling by the refrigerator, wherein a switching superconducting wire is wound. Winding part, and a heater for heating the winding part,
A permanent current switch, comprising: a heat insulating material in contact with the winding portion; and a cooling member for conducting and cooling the winding portion through the heat insulating material.
材、冷却部材が、各々同心円状に配置されている請求項
１に記載の永久電流スイッチ。2. The permanent current switch according to claim 1, wherein the heater, the superconducting wire winding portion, the heat insulating material, and the cooling member are respectively arranged concentrically.
伝導金属材料からなる請求項１または２に記載の永久電
流スイッチ。3. The permanent current switch according to claim 1, wherein said cooling member is made of a good heat conductive metal material such as copper or aluminum.
をαW としたとき、断熱材の同心円の径方向の熱通過率
が５０αW/(m2 ・K)以下である請求項２または３に記載
の永久電流スイッチ。4. The heat transfer material according to claim 2 , wherein a heat transfer coefficient in a radial direction of a concentric circle of the heat insulating material is 50 αW / (m 2 · K) or less, where αW is a cooling capacity at 3 to 8 K of the refrigerator. A permanent current switch as described.
・K)以上である請求項４に記載の永久電流スイッチ。5. The heat transmission rate of the heat insulating material is 0.5 αW / (m 2
The permanent current switch according to claim 4, wherein K is not less than K).
ン、ＦＲＰ、ベークライト、エポキシ樹脂、ワックス、
またはこれらの複合材の内から選択されるものである請
求項１乃至５のいずれか１項に記載の永久電流スイッ
チ。6. The heat insulating material is putty, Teflon, nylon, FRP, bakelite, epoxy resin, wax,
The permanent current switch according to any one of claims 1 to 5, wherein the permanent current switch is selected from among these composite materials.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29264996A JP3382794B2 (en) | 1996-11-01 | 1996-11-05 | Permanent current switch |
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8-291771 | 1996-11-01 | ||
| JP29177196 | 1996-11-01 | ||
| JP29264996A JP3382794B2 (en) | 1996-11-01 | 1996-11-05 | Permanent current switch |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10189324A true JPH10189324A (en) | 1998-07-21 |
| JP3382794B2 JP3382794B2 (en) | 2003-03-04 |
Family
ID=26558695
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29264996A Expired - Lifetime JP3382794B2 (en) | 1996-11-01 | 1996-11-05 | Permanent current switch |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3382794B2 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104579280A (en) * | 2014-11-18 | 2015-04-29 | 中国科学院电工研究所 | Superconductive switch for conducting cooling superconductive magnet |
| CN106920633A (en) * | 2017-04-26 | 2017-07-04 | 国家电网公司 | Bushing shell for transformer raises holder structure and its installation method |
-
1996
- 1996-11-05 JP JP29264996A patent/JP3382794B2/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104579280A (en) * | 2014-11-18 | 2015-04-29 | 中国科学院电工研究所 | Superconductive switch for conducting cooling superconductive magnet |
| CN106920633A (en) * | 2017-04-26 | 2017-07-04 | 国家电网公司 | Bushing shell for transformer raises holder structure and its installation method |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3382794B2 (en) | 2003-03-04 |
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