JPH10332458A - Cryogenic refrigerant liquid level gage - Google Patents
Cryogenic refrigerant liquid level gageInfo
- Publication number
- JPH10332458A JPH10332458A JP13662197A JP13662197A JPH10332458A JP H10332458 A JPH10332458 A JP H10332458A JP 13662197 A JP13662197 A JP 13662197A JP 13662197 A JP13662197 A JP 13662197A JP H10332458 A JPH10332458 A JP H10332458A
- Authority
- JP
- Japan
- Prior art keywords
- liquid level
- detecting element
- liquid
- heater
- cryogenic refrigerant
- 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.)
- Pending
Links
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、超電導磁石やその
他の機器を保冷する極低温容器に使用される極低温冷媒
液面計に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic refrigerant level gauge used for a cryogenic vessel for keeping superconducting magnets and other equipment cool.
【０００２】[0002]
【従来の技術】極低温容器内の液体ヘリウムなどの極低
温冷媒の液面を計測する方法として、超電導体の超電導
−常電導遷移を利用したものがある。この方法を用いた
極低温冷媒液面計について図２を用いて説明する。図２
において、１は貯液冷媒の温度で超電導状態になる超電
導線からなる液面検出素子、２は液面検出素子１の上部
に設けられたヒーター線、３ａ、３ｂ、４ａ、４ｂは銅
線からなるリード線である。５は極低温容器で、この極
低温容器５の上部には、リード線３ａ、３ｂ、４ａ、４
ｂを導入するとともに、極低温冷媒を注入するための注
入口６が設けられている。液面検出素子１は超電導線が
略垂直になるように極低温容器５内に設置されている。
なお、液面検出素子１、ヒーター線２、リード線３ａ、
３ｂ、４ａ、４ｂの線径は、極低温容器５内への熱流入
をできるだけ小さくするため、できるだけ細くなってい
る。ヒーター線２は、例えばコンスタンタン線からな
り、その一端は液面検出素子１の上端に接続され、その
上部に螺旋状に巻き付けられている。ヒーター線２の他
端はリード線３ｂを介して電流源７に接続している。ま
た、リード線３ａは一端が液面検出素子１の下端に接続
し、他端が電流源７に接続している。さらに、リード線
４ａは一端が液面検出素子１の下端に接続し、他端が電
圧計８に接続している。なお、液面検出素子１の上端か
らはリード線４ｂが電圧計８に接続している。2. Description of the Related Art As a method for measuring the liquid level of a cryogenic refrigerant such as liquid helium in a cryogenic container, there is a method utilizing a superconducting-normal conducting transition of a superconductor. A cryogenic refrigerant level gauge using this method will be described with reference to FIG. FIG.
In the drawing, 1 is a liquid level detecting element composed of a superconducting wire which is brought into a superconducting state at the temperature of the liquid refrigerant, 2 is a heater wire provided above the liquid level detecting element 1, 3a, 3b, 4a and 4b are copper wires. Lead wire. Reference numeral 5 denotes a cryogenic container, and lead wires 3a, 3b, 4a, 4
Injection port 6 for introducing b and introducing a cryogenic refrigerant is provided. The liquid level detecting element 1 is installed in the cryogenic vessel 5 so that the superconducting wire is substantially vertical.
The liquid level detecting element 1, the heater wire 2, the lead wire 3a,
The wire diameters of 3b, 4a, and 4b are as small as possible in order to minimize the heat flow into the cryogenic vessel 5. The heater wire 2 is made of, for example, a constantan wire, one end of which is connected to the upper end of the liquid level detecting element 1 and spirally wound around the upper portion. The other end of the heater wire 2 is connected to a current source 7 via a lead wire 3b. One end of the lead wire 3 a is connected to the lower end of the liquid level detecting element 1, and the other end is connected to the current source 7. Further, one end of the lead wire 4 a is connected to the lower end of the liquid level detecting element 1, and the other end is connected to the voltmeter 8. A lead wire 4 b is connected to the voltmeter 8 from the upper end of the liquid level detecting element 1.
【０００３】この極低温冷媒液面計は以下のように作動
する。図２において、液面検出素子１の途中、レベルＡ
まで液状極低温冷媒が存在しており、液面検出素子１は
その液状極低温冷媒の温度で超電導状態になっている。
この状態で電流源７よりヒーター線２および液面検出素
子１に電流を流すと、液面検出素子１のレベルＡよりも
上側の部分（極低温冷媒が気化している）はヒーター線
２により加熱され、超電導状態が破壊されて常電導状態
になる。液面検出素子１は極低温冷媒の液面レベルＡを
境にして超電導状態と常電導状態に明確に分かれるの
で、液面検出素子１のレベルＡよりも上側の部分には通
電により電圧が発生する。この電圧と極低温冷媒の液面
レベルＡの間には一対一に対応する一定の関係があるた
め、この電圧値から極低温冷媒の液面レベルを精度よく
計測することができる。なお、図２においては、液面検
出素子１は垂直に配置された直線状の超電導線で構成さ
れている例について説明したが、極低温冷媒の液面レベ
ルＡとそのレベルより上側の液面検出素子１の長さが一
対一に対応するようにして、液面検出素子１を種々の直
線に配置した例がある。また、液面検出素子は直線に配
置されるとは限らない。例えば、核磁気共鳴用円筒形コ
イルには垂直に設置されるリング状の極低温容器が用い
られ、線状の液面検出素子は上下方向に円弧をなして極
低温容器内に配置される。[0003] This cryogenic refrigerant level gauge operates as follows. In FIG. 2, in the middle of the liquid level detecting element 1, the level A
The liquid cryogenic refrigerant is present up to this point, and the liquid level detecting element 1 is in a superconducting state at the temperature of the liquid cryogenic refrigerant.
In this state, when a current flows from the current source 7 to the heater wire 2 and the liquid level detecting element 1, a portion above the level A of the liquid level detecting element 1 (the cryogenic refrigerant is vaporized) is heated by the heater line 2. When heated, the superconducting state is destroyed and becomes a normal conducting state. Since the liquid level detecting element 1 is clearly divided into a superconducting state and a normal conducting state at the liquid level level A of the cryogenic refrigerant, a voltage is generated by energizing a portion above the level A of the liquid level detecting element 1. I do. Since there is a one-to-one correspondence between the voltage and the liquid level A of the cryogenic refrigerant, the liquid level of the cryogenic refrigerant can be accurately measured from this voltage value. In FIG. 2, the example in which the liquid level detecting element 1 is constituted by a linear superconducting wire arranged vertically is described, but the liquid level A of the cryogenic refrigerant and the liquid level above the level are described. There are examples in which the liquid level detecting elements 1 are arranged in various straight lines such that the lengths of the detecting elements 1 correspond one-to-one. Further, the liquid level detecting elements are not always arranged in a straight line. For example, a vertically arranged ring-shaped cryogenic vessel is used for the cylindrical coil for nuclear magnetic resonance, and the linear liquid level detecting element is arranged inside the cryogenic vessel in a vertical arc.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、上述の
極低温冷媒液面計には次のような問題があった。即ち、
極低温冷媒を補給するために極低温容器５の注入口６を
開くと、常温の大気中の水分が極低温容器５内に流入
し、この水分が液面検出素子１の極低温冷媒液面よりも
上側の部位に氷結することがある。そうすると、ヒータ
ー線２を加熱して極低温冷媒の液面レベルを計測する際
に、ヒーター線２の発熱がこの氷結体１０に吸熱され、
液面検出素子１の氷結体１０と極低温冷媒の液面レベル
Ａ間の部分が超電導状態から常電導状態に転移せず、液
面レベルを計測することが出来なくなる。この様子を図
３（ａ）、（ｂ）を用いて説明する。図３（ａ）は、極
低温冷媒液面が時間とともに低下する様子を示し、極低
温冷媒液面計が正常に作動しているときは、この液面に
対応した電圧を発生する。しかしながら、例えば、液面
検出素子１に上述の氷結体１０が付着した異常時には、
液面が時間とともに低下し、氷結体１０の付着した液面
検出素子１の部位よりも低下しても、液面検出素子１の
氷結体１０が付着した部位よりも下側の部分は超電導状
態のままになっている。このため、通電により液面検出
素子１に発生する電圧は、氷結体１０が付着した部位に
液面があるような値となる。従って、極低温冷媒液面計
は、図３（ｂ）に示すように、氷結体１０よりも液面が
下がっても液面が、見かけ上、氷結体１０の位置にある
ような電圧を発生する。However, the cryogenic refrigerant level gauge described above has the following problems. That is,
When the inlet 6 of the cryogenic container 5 is opened to replenish the cryogenic refrigerant, moisture in the normal-temperature atmosphere flows into the cryogenic container 5, and the moisture is supplied to the cryogenic refrigerant level of the liquid level detecting element 1. Freezing may occur in areas above. Then, when the heater wire 2 is heated to measure the liquid level of the cryogenic refrigerant, the heat generated by the heater wire 2 is absorbed by the frozen body 10,
The portion between the frozen body 10 of the liquid level detecting element 1 and the liquid level A of the cryogenic refrigerant does not change from the superconducting state to the normal conducting state, and the liquid level cannot be measured. This situation will be described with reference to FIGS. FIG. 3A shows how the cryogenic refrigerant liquid level decreases with time. When the cryogenic refrigerant liquid level gauge operates normally, a voltage corresponding to this liquid level is generated. However, for example, when the above-mentioned frozen matter 10 adheres to the liquid level detecting element 1,
Even if the liquid level decreases with time and becomes lower than the portion of the liquid level detecting element 1 to which the frozen body 10 has adhered, the portion of the liquid level detecting element 1 below the portion to which the frozen body 10 has adhered is in a superconducting state. Remains. For this reason, the voltage generated in the liquid level detecting element 1 by energization has a value such that there is a liquid level at the site where the frozen matter 10 has adhered. Therefore, as shown in FIG. 3B, the cryogenic refrigerant level gauge generates a voltage such that the liquid level is apparently at the position of the frozen body 10 even if the liquid level falls below the frozen body 10. I do.
【０００５】このような極低温容器５内に超電導マグネ
ットを設置し、この超電導マグネットを各種の目的のた
めに稼動させる場合には、一旦、上記氷結体１０が形成
された後、再び液面レベルの計測が可能な状態に戻すた
めには、極低温容器５内の温度を常温まで上げて、氷結
体１０を融解、除去する必要があるので、超電導マグネ
ットの稼働率が低下する。[0005] When a superconducting magnet is installed in such a cryogenic vessel 5 and the superconducting magnet is operated for various purposes, once the above-mentioned frozen body 10 is formed, the liquid level is changed again. In order to return to the state where measurement of the temperature is possible, it is necessary to raise the temperature in the cryogenic vessel 5 to normal temperature and to melt and remove the frozen body 10, so that the operating rate of the superconducting magnet decreases.
【０００６】[0006]
【課題を解決するための手段】本発明は上記問題点を解
決すべくなされたもので、上下方向に配置される超電導
線からなる液面検出素子と、前記液面検出素子の上端部
を加熱する加熱手段（第１加熱手段とする）とを有する
極低温冷媒液面計において、前記液面検出素子の測定し
ようとする極低温冷媒液面よりも上側の所望の部位を加
熱する加熱手段（第２加熱手段とする）を設けたことを
特徴とするものである。ここで、液面検出素子の超電導
線が配置される上下方向とは、直線状とは限らず、円弧
などの曲線状をなして両端部が上端、下端に位置するよ
うに配置される場合も含むものとする。また、第２加熱
手段が加熱する液面検出素子の所望の部位とは、測定し
ようとする極低温冷媒液面よりも上側に位置し、液面検
出素子に付着した氷結体を解氷する部位を指す。この液
面検出素子の氷結体を解氷する部位は、常に極低温冷媒
液面よりも上側に位置しているのではなく、少なくとも
測定時点で極低温冷媒液面よりも上側に位置していれば
よい。なお、第１加熱手段は液面検出素子の極低温冷媒
液面より上部を常電導化するに要する最低限の熱量を発
生するとともに、液状極低温冷媒の損失をできるだけ少
なくするようにするのに対して、第２加熱手段は上記氷
結体を解氷するに必要な熱量を発生するので、第２加熱
手段の発熱量は通常、第１加熱手段の発熱量よりも大き
くなる。SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and includes a liquid level detecting element comprising a superconducting wire arranged in a vertical direction and an upper end of the liquid level detecting element. A heating means (hereinafter referred to as a first heating means) for heating a desired portion above a cryogenic refrigerant liquid level to be measured by the liquid level detecting element. (Referred to as second heating means). Here, the vertical direction in which the superconducting wires of the liquid level detecting element are arranged is not limited to a straight line, and may be arranged in a curved shape such as an arc so that both ends are located at the upper end and the lower end. Shall be included. Further, the desired portion of the liquid level detecting element heated by the second heating means is a portion located above the liquid level of the cryogenic refrigerant to be measured, and for freezing the frozen matter attached to the liquid level detecting element. Point to. The portion of the liquid level detecting element that defrosts the frozen body is not always located above the cryogenic refrigerant liquid level, but is located at least at the measurement time point above the cryogenic refrigerant liquid level. I just need. The first heating means generates the minimum amount of heat required to make the upper part of the liquid level detecting element above the cryogenic refrigerant liquid level normal-conducting, and minimizes the loss of the liquid cryogenic refrigerant. On the other hand, since the second heating means generates an amount of heat required to defrost the frozen matter, the heat value of the second heating means is generally larger than the heat value of the first heating means.
【０００７】上述のように本発明によれば、第２加熱手
段を設けて液面検出素子を加熱すると、液面検出素子に
付着した氷結体を解氷することができるので、極低温冷
媒液面レベルの計測が妨げられることがない。また、極
低温容器内の温度を常温まで上げることなく、氷結体を
融解、除去することができるので、極低温容器内に設置
された超電導マグネットなどの機器の稼働率が向上す
る。[0007] As described above, according to the present invention, when the second heating means is provided to heat the liquid level detecting element, the icy matter attached to the liquid level detecting element can be thawed. Surface level measurement is not hindered. In addition, since the frozen matter can be melted and removed without raising the temperature in the cryogenic container to room temperature, the operating rate of devices such as superconducting magnets installed in the cryogenic container is improved.
【０００８】[0008]
【発明の実施の形態】以下、図面に基づいて本発明の実
施の形態を詳細に説明する。図１は、本発明にかかる極
低温冷媒液面計の一実施形態の説明図である。図１にお
いて、図２に関して説明した部分と同部分は同符号で指
示してある。本実施形態において、上下方向に配置され
た超電導線からなる液面検出素子１は、液状極低温冷媒
の液面がゼロで、言い換えると、全体が常電導体になっ
ている状態で数１０Ωの抵抗を有している。また、ヒー
ター線２はコンスタンタンなどの低温での温度による抵
抗変化の小さい線材から構成されている第１加熱手段で
ある。ヒーター線２の一端は液面検出素子１の上端に電
気的に直列に接続し、液面検出素子１の上端部に数ｃｍ
の長さで螺旋状に接触して巻き付けられており、その他
端はリード線３ｂを介して電流源７に接続している。ま
た、液面検出素子１の下端は２本の銅線からなるリード
線３ａ、４ａに接続しており、リード線３ａは電流源７
に接続し、リード線４ａは電圧計８に接続している。ま
た、液面検出素子１の上端はリード線４ｂで電圧計８に
接続している。１１ａ、１１ｂ、１１ｃは氷結体を融解
するための第２加熱手段となるヒーターであり、液面検
出素子１の氷結体の付着を防止する部位に設けられてい
る。即ち、もっとも高い位置に設けられたヒーター１１
ａは液面のもっとも高くなる位置の上方近傍とし、もっ
とも低い位置に設けられたヒーター１１ｃは液面のもっ
とも低くなる位置の上方近傍とする。これらのヒーター
１１ａ、１１ｂ、１１ｃは、第１加熱手段のヒーター線
２と同様にコンスタンタン線を液面検出素子１に巻き付
けて構成するが、氷結体を融解するために必要な熱容量
をもたせるために、ヒーター線２とは形状、線径を異に
し、別の電流源１２に接続して、通電量も大きくする。Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an explanatory diagram of one embodiment of a cryogenic refrigerant level gauge according to the present invention. 1, the same parts as those described with reference to FIG. 2 are indicated by the same reference numerals. In the present embodiment, the liquid level detecting element 1 composed of vertically arranged superconducting wires has a liquid level of the liquid cryogenic refrigerant of zero, in other words, several tens of ohms when the whole is a normal conductor. Has resistance. The heater wire 2 is a first heating means made of a wire such as constantan which has a small resistance change due to a low temperature. One end of the heater wire 2 is electrically connected in series to the upper end of the liquid level detecting element 1, and several cm
And is wound spirally in contact with the length of, and the other end is connected to a current source 7 via a lead wire 3b. The lower end of the liquid level detecting element 1 is connected to lead wires 3a and 4a made of two copper wires.
, And the lead wire 4 a is connected to the voltmeter 8. The upper end of the liquid level detecting element 1 is connected to a voltmeter 8 by a lead wire 4b. Reference numerals 11a, 11b, and 11c denote heaters serving as second heating means for melting the frozen matter, and are provided at portions of the liquid level detecting element 1 where the frozen matter is prevented from adhering. That is, the heater 11 provided at the highest position
“a” is near the position above the highest level of the liquid surface, and the heater 11c provided at the lowest position is near the above position where the liquid level is lowest. These heaters 11a, 11b, and 11c are configured by winding a constantan wire around the liquid level detecting element 1 in the same manner as the heater wire 2 of the first heating means, but in order to have a heat capacity necessary for melting the frozen matter. The heater wire 2 is different in shape and wire diameter from the heater wire 2 and is connected to another current source 12 to increase the amount of current.
【０００９】これらのヒーター１１ａ、１１ｂ、１１ｃ
は、以下のように操作する。即ち、極低温冷媒液面が当
初の最も高い位置（ヒーター１１ａの近傍下側）から低
下しはじめて、極低温冷媒液面計が示す液面の位置が時
間とともに変化しなくなり、見かけ上、液面が一定にな
った場合（ヒーター１１ａと液面間に氷結体が付着され
たことを示す）には、ヒーター１１ａを加熱し、液面が
低下すること（氷結体が融解したこと）を確認する。ま
た、液面がヒーター１１ｂよりも下側で極低温冷媒液面
計が示す液面の位置が時間とともに変化しなくなった時
点で、ヒーター１１ｂを加熱し、液面が低下することを
確認する。ヒーター１１ｃについても同様である。These heaters 11a, 11b, 11c
Operates as follows. That is, the cryogenic refrigerant liquid level starts to decrease from the initial highest position (lower side near the heater 11a), and the liquid level position indicated by the cryogenic refrigerant liquid level meter does not change with time, and apparently the liquid level Is constant (indicating that frozen matter has adhered between the heater 11a and the liquid level), the heater 11a is heated to confirm that the liquid level has dropped (the frozen matter has melted). . Further, when the liquid level is lower than the heater 11b and the position of the liquid level indicated by the cryogenic refrigerant liquid level gauge does not change with time, the heater 11b is heated to confirm that the liquid level decreases. The same applies to the heater 11c.
【００１０】なお、上記実施形態では、液面検出素子１
がほぼ直線状の場合を示したが、液面検出素子１は必ず
しも直線状である必要はなく、円弧の一部など、曲線状
であっても差し支えない。また、上記実施形態では、第
２加熱手段としてのヒーター１１ａ、１１ｂ、１１ｃは
線状としたが、ブロック状でもよい。また、第２加熱手
段として３個のヒーター１１ａ、１１ｂ、１１ｃを設け
たが、３個に限定されることはなく、解氷しようとする
氷結体の位置に応じて必要な数のヒーターを設けること
ができる。さらに、第２加熱手段として１個のヒーター
を液面検出素子１にそって上下に移動可能に設けてもよ
い。In the above embodiment, the liquid level detecting element 1
Is substantially linear, but the liquid level detecting element 1 is not necessarily required to be linear, but may be curved such as a part of an arc. In the above embodiment, the heaters 11a, 11b, and 11c as the second heating means are linear, but may be block-shaped. Although three heaters 11a, 11b, and 11c are provided as the second heating means, the number of heaters is not limited to three, and a necessary number of heaters may be provided according to the position of the iced body to be thawed. be able to. Further, one heater may be provided as the second heating means so as to be vertically movable along the liquid level detecting element 1.
【００１１】[0011]
【発明の効果】本発明によれば、大気中の水分が極低温
容器内に流入し、液面検出素子の極低温冷媒の液面より
も上側の部位に氷結しても、極低温容器内全体を温める
ことなく液面レベルを計測することができるという優れ
た効果がある。従って、極低温容器内に超電導マグネッ
トなどの機器を設置した場合には、その稼働率を向上さ
せることができる。According to the present invention, even if moisture in the atmosphere flows into the cryogenic container and freezes on a portion of the liquid level detecting element above the liquid surface of the cryogenic refrigerant, the liquid in the cryogenic container can be cooled. There is an excellent effect that the liquid level can be measured without warming the whole. Therefore, when equipment such as a superconducting magnet is installed in the cryogenic container, the operating rate can be improved.
【図１】本発明に係る極低温冷媒液面計の一実施形態の
説明図である。FIG. 1 is an explanatory diagram of one embodiment of a cryogenic refrigerant level gauge according to the present invention.
【図２】従来の極低温冷媒液面計の説明図である。FIG. 2 is an explanatory diagram of a conventional cryogenic refrigerant level gauge.
【図３】（ａ）、（ｂ）は、従来の極低温冷媒液面計の
問題点の説明図である。FIGS. 3 (a) and 3 (b) are explanatory diagrams of problems of a conventional cryogenic refrigerant level gauge.
１ 液面検出素子 ２ ヒーター線 ３ａ、３ｂ、４ａ、４ｂ リード線 ５ 極低温容器 ６ 注入口 ７、１２ 電流源 ８ 電圧計 １０ 氷結体 １１ａ、１１ｂ、１１ｃ ヒーター DESCRIPTION OF SYMBOLS 1 Liquid-level detection element 2 Heater wire 3a, 3b, 4a, 4b Lead wire 5 Cryogenic vessel 6 Inlet 7, 12 Current source 8 Voltmeter 10 Freezing 11a, 11b, 11c Heater
Claims (1)
液面検出素子と、前記液面検出素子の上端部を加熱する
加熱手段を有する極低温冷媒液面計において、前記液面
検出素子の測定しようとする極低温冷媒液面よりも上側
の所望の部位を加熱する加熱手段を設けたことを特徴と
する極低温冷媒液面計。1. A cryogenic refrigerant level gauge having a liquid level detecting element comprising a superconducting wire arranged vertically and a heating means for heating an upper end of the liquid level detecting element, wherein: A cryogenic refrigerant level gauge provided with heating means for heating a desired portion above a cryogenic refrigerant liquid level to be measured.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13662197A JPH10332458A (en) | 1997-05-27 | 1997-05-27 | Cryogenic refrigerant liquid level gage |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13662197A JPH10332458A (en) | 1997-05-27 | 1997-05-27 | Cryogenic refrigerant liquid level gage |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH10332458A true JPH10332458A (en) | 1998-12-18 |
Family
ID=15179592
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13662197A Pending JPH10332458A (en) | 1997-05-27 | 1997-05-27 | Cryogenic refrigerant liquid level gage |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH10332458A (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005246066A (en) * | 2004-03-05 | 2005-09-15 | Ge Medical Systems Global Technology Co Llc | System and method for defrosting re-condensing device for liquid cooling zero boil off type mr magnet |
| JP2008175640A (en) * | 2007-01-17 | 2008-07-31 | Mitsubishi Electric Corp | Refrigerant liquid level measuring device, refrigerant liquid level measuring method, and superconductive magnet device using it |
| CN100451571C (en) * | 2003-05-16 | 2009-01-14 | Ge医疗系统环球技术有限公司 | Liquid helium level sensor for use in a cryogenic environment and method for assembling same |
| US8225653B2 (en) | 2006-03-06 | 2012-07-24 | Magna Steyr Fahrzeugtechnik Ag & Co. Kg | Level sensor for cryogenic liquids, and receptacle comprising such a level sensor |
| JP2013156036A (en) * | 2012-01-26 | 2013-08-15 | Toshiba Corp | Liquid level detecting device and method |
| JP6108508B1 (en) * | 2016-06-10 | 2017-04-05 | 大陽日酸株式会社 | Liquid level detector, cryopreservation container, and liquid level detection method |
-
1997
- 1997-05-27 JP JP13662197A patent/JPH10332458A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100451571C (en) * | 2003-05-16 | 2009-01-14 | Ge医疗系统环球技术有限公司 | Liquid helium level sensor for use in a cryogenic environment and method for assembling same |
| JP2005246066A (en) * | 2004-03-05 | 2005-09-15 | Ge Medical Systems Global Technology Co Llc | System and method for defrosting re-condensing device for liquid cooling zero boil off type mr magnet |
| JP4745687B2 (en) * | 2004-03-05 | 2011-08-10 | ジーイー・メディカル・システムズ・グローバル・テクノロジー・カンパニー・エルエルシー | System and method for deicing a recondenser for a liquid cooled zero boil-off MR magnet |
| US8225653B2 (en) | 2006-03-06 | 2012-07-24 | Magna Steyr Fahrzeugtechnik Ag & Co. Kg | Level sensor for cryogenic liquids, and receptacle comprising such a level sensor |
| JP2008175640A (en) * | 2007-01-17 | 2008-07-31 | Mitsubishi Electric Corp | Refrigerant liquid level measuring device, refrigerant liquid level measuring method, and superconductive magnet device using it |
| JP2013156036A (en) * | 2012-01-26 | 2013-08-15 | Toshiba Corp | Liquid level detecting device and method |
| JP6108508B1 (en) * | 2016-06-10 | 2017-04-05 | 大陽日酸株式会社 | Liquid level detector, cryopreservation container, and liquid level detection method |
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