JP3529608B2 - Sample temperature variable device for magnetic resonance equipment - Google Patents
Sample temperature variable device for magnetic resonance equipmentInfo
- Publication number
- JP3529608B2 JP3529608B2 JP32607497A JP32607497A JP3529608B2 JP 3529608 B2 JP3529608 B2 JP 3529608B2 JP 32607497 A JP32607497 A JP 32607497A JP 32607497 A JP32607497 A JP 32607497A JP 3529608 B2 JP3529608 B2 JP 3529608B2
- Authority
- JP
- Japan
- Prior art keywords
- heater
- liquid nitrogen
- dewar
- magnetic resonance
- sample temperature
- 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.)
- Expired - Fee Related
Links
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は、磁気共鳴装置にお
いて用いられる試料温度可変装置に関する。
【０００２】
【従来の技術】図１は、従来の磁気共鳴装置用試料温度
可変装置のヒータ過熱断線防止機構を示したものであ
る。図中、液体窒素１が入った液体窒素デュワー２内に
ヒータ３が挿入されている。ヒータ３に電流が流れると
熱が発生し、液体窒素１が気化して低温の窒素ガス４が
発生し、このガスが、図示しない試料測定部における室
温以下の温度コントロール用ガスとして使用される。
【０００３】液体窒素デュワー２内に挿入されたヒータ
３は、過熱による断線を防止するために、抵抗器５、
６、及び可変抵抗器７と組み合わせてブリッジ回路を形
成している。そして、液体窒素１がデュワー２内にある
場合は、ブリッジ回路がバランスするように可変抵抗器
７の抵抗値が調整されている。このため、ブリッジ回路
のｂ−ｄ間に電圧は発生しない。
【０００４】ところが、液体窒素１がなくなって、ヒー
タ３が空だき状態になると、ヒータ３の温度が上昇し、
ヒータ３の抵抗値が増加することによってブリッジ回路
のバランスが崩れ、ブリッジ回路のｂ−ｄ間に電圧Ｖd
が発生する。その結果、差動増幅器８の出力電圧は、比
較器９の電圧Ｖsよりも大きくなり、リレー１１を制御
するドライバー１０が作動して、ヒータ電源電圧Ｖhが
自動的にオフとなり、過熱によるヒータ３の断線が未然
に防止される。
【０００５】
【発明が解決しようとする課題】ところで、１つの磁気
共鳴装置に複数個の液体窒素デュワー（例えば１０リッ
トルデュワーと３０リットルデュワー）が付属されてい
る場合、それぞれの液体窒素デュワー用ヒータの抵抗値
は必ずしも同じ値ではないため、過熱防止用のブリッジ
回路を組んだ場合、一方のヒータでバランスを取れるよ
うに可変抵抗器７を調整すると、他方のヒータではブリ
ッジのバランスが取れず、液体窒素がなくなってもリレ
ーが作動せず、ヒータの過熱・断線を引き起こしたり、
あるいは液体窒素がデュワー内にあるのにリレーが作動
して、ヒータ電源電圧が切れ、温度制御ができなくなる
という問題があった。
【０００６】本発明の目的は、上述した点に鑑み、抵抗
値の異なるヒータを用いて温度制御を行なっても、ヒー
タが過熱してヒータ切れを起こしたり、ヒータ電源が切
れて温度制御ができなくなったりしない試料温度可変装
置を提供することにある。
【０００７】
【課題を解決するための手段】この目的を達成するた
め、本発明の磁気共鳴用試料温度可変装置は、デュワー
に蓄えられた液体窒素中でヒータを加熱することによっ
て低温の窒素ガスを気化・発生させ、そのガスを試料管
に吹き付けることによって試料温度を制御するように構
成すると共に、デュワー内の液体窒素が消費されてなく
なると、前記ヒータを構成要素として含むブリッジ回路
でヒータの温度が上昇して抵抗値が変化することに由来
するバランスの崩れを検出して、ヒータへの電力供給を
断つように構成した磁気共鳴装置用試料温度可変装置に
おいて、ヒータに直列に接続される可変抵抗器を設けた
ことを特徴としている。
【０００８】
【発明の実施の形態】以下、図面を参照して、本発明の
実施の形態を説明する。図２は、本発明にかかる磁気共
鳴装置用試料温度可変装置のデュワー部分である。図
中、液体窒素１が入った液体窒素デュワー２内にヒータ
３が挿入されている。ヒータ３に電流が流れると熱が発
生し、液体窒素１が気化して低温の窒素ガス４が発生
し、このガスが、図示しない試料測定部における室温以
下の温度コントロール用ガスとして使用される。これら
は図１と同じである。図２では、さらに、デュワー２内
のヒータ３と直列になるように、ヒータ抵抗調整用可変
抵抗器１２がデュワー２外の回路部分に挿入されてい
る。このヒータ抵抗調整用可変抵抗器１２の使用方法は
次の通りである。
【０００９】まず、使用される複数のヒータの中で、最
も高い抵抗値を持つヒータを図１のように接続し、デュ
ワー内に液体窒素を充填した後、ブリッジ回路がバラン
スするように可変抵抗器７を調整する。
【００１０】次に、図２に示すようなヒータ抵抗調整用
可変抵抗器１２を付加した他のヒータを図１のように接
続し、ブリッジ回路がバランスするようにヒータ抵抗調
整用可変抵抗器１２を調整する。これによって、個々の
ヒータごとの抵抗値の違いがヒータ抵抗調整用可変抵抗
器１２で補正され、どのヒータを使用しても、同じよう
にブリッジ回路のバランスが取れるようになる。
【００１１】尚、図２では、液体窒素デュワー２の外部
にヒータ抵抗調整用可変抵抗器１２が設けられている
が、これは液体窒素デュワー２と一体型であってもよ
い。
【００１２】その場合は、使用されるヒータの中で、最
も高い抵抗値を持つヒータと組み合わされる液体窒素デ
ュワーに付属するヒータ抵抗調整用可変抵抗器の値をゼ
ロに調整し、デュワー内に液体窒素を充填した後、ブリ
ッジ回路がバランスするように試料温度可変装置内の可
変抵抗器を調整する。
【００１３】次に、他の液体窒素デュワー及びヒータで
ブリッジ回路を構成し、デュワー内に液体窒素を充填し
た後、ブリッジ回路がバランスするように、液体窒素デ
ュワー付属のヒータ抵抗調整用可変抵抗器を調整する。
【００１４】
【発明の効果】以上述べたごとく、本発明の磁気共鳴装
置用試料温度可変装置を用いれば、ヒータごとに抵抗値
の違いがあっても、その違いを補正することができ、ブ
リッジ回路のバランスを取ることができるので、液体窒
素がデュワー内にある場合にはヒータが正しく稼動し、
液体窒素がなくなった場合にはヒータの過熱をくい止め
るリレー回路が正しく作動するようなヒータ保護機構を
提供することができる。Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a sample temperature variable device used in a magnetic resonance apparatus. FIG. 1 shows a heater overheating disconnection prevention mechanism of a conventional sample temperature variable device for a magnetic resonance apparatus. In the figure, a heater 3 is inserted into a liquid nitrogen dewar 2 containing liquid nitrogen 1. When an electric current flows through the heater 3, heat is generated, and the liquid nitrogen 1 is vaporized to generate a low-temperature nitrogen gas 4. This gas is used as a temperature control gas at room temperature or lower in a sample measuring unit (not shown). [0003] The heater 3 inserted into the liquid nitrogen dewar 2 is provided with a resistor 5 and a resistor 5 to prevent disconnection due to overheating.
6 and the variable resistor 7 to form a bridge circuit. When the liquid nitrogen 1 is in the dewar 2, the resistance of the variable resistor 7 is adjusted so that the bridge circuit is balanced. Therefore, no voltage is generated between b and d of the bridge circuit. However, when the liquid nitrogen 1 runs out and the heater 3 becomes empty, the temperature of the heater 3 rises,
When the resistance value of the heater 3 increases, the balance of the bridge circuit is broken, and the voltage V d is applied between b and d of the bridge circuit.
Occurs. By a result, the output voltage of the differential amplifier 8 is greater than the voltage V s of the comparator 9, and the driver 10 is actuated to control the relay 11, the heater power supply voltage V h is automatically turned off, overheating Disconnection of the heater 3 is prevented beforehand. [0005] When a plurality of liquid nitrogen dewars (for example, 10 liter dewar and 30 liter dewar) are attached to one magnetic resonance apparatus, each liquid nitrogen dewar heater is provided. Are not necessarily the same value. Therefore, when a bridge circuit for preventing overheating is formed, if the variable resistor 7 is adjusted so as to balance with one heater, the bridge cannot be balanced with the other heater. Even if liquid nitrogen runs out, the relay will not operate, causing overheating and disconnection of the heater,
Alternatively, there is a problem that the relay is activated even though liquid nitrogen is in the dewar, the heater power supply voltage is cut off, and the temperature cannot be controlled. SUMMARY OF THE INVENTION In view of the above, it is an object of the present invention to control the temperature by using heaters having different resistance values, the heater may be overheated and the heater may be cut off, or the heater power may be cut off to control the temperature. An object of the present invention is to provide a sample temperature variable device which does not disappear. In order to achieve this object, a magnetic resonance sample temperature varying apparatus according to the present invention comprises a nitrogen heater at a low temperature by heating a heater in liquid nitrogen stored in a dewar. Is vaporized and generated, and the gas is blown to the sample tube to control the sample temperature.When the liquid nitrogen in the dewar is no longer consumed, the bridge circuit including the heater as a component serves as a heater for the heater. In a sample temperature variable device for a magnetic resonance apparatus configured to detect an imbalance caused by a change in resistance value due to a rise in temperature and to cut off power supply to the heater, the device is connected in series to the heater. A variable resistor is provided. Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a dewar section of the sample temperature variable device for a magnetic resonance apparatus according to the present invention. In the figure, a heater 3 is inserted into a liquid nitrogen dewar 2 containing liquid nitrogen 1. When an electric current flows through the heater 3, heat is generated, and the liquid nitrogen 1 is vaporized to generate a low-temperature nitrogen gas 4. This gas is used as a temperature control gas at room temperature or lower in a sample measuring unit (not shown). These are the same as FIG. In FIG. 2, a variable resistor 12 for adjusting the heater resistance is inserted in a circuit portion outside the dewar 2 so as to be in series with the heater 3 in the dewar 2. The method of using the heater resistance adjusting variable resistor 12 is as follows. First, a heater having the highest resistance value among a plurality of heaters to be used is connected as shown in FIG. 1, and after filling the dewar with liquid nitrogen, the variable resistor is adjusted so that the bridge circuit is balanced. Adjust the vessel 7. Next, another heater to which the heater resistance adjusting variable resistor 12 as shown in FIG. 2 is added is connected as shown in FIG. 1, and the heater resistance adjusting variable resistor 12 is adjusted so that the bridge circuit is balanced. To adjust. As a result, the difference in the resistance value of each heater is corrected by the variable resistor 12 for adjusting the heater resistance, so that the bridge circuit can be similarly balanced regardless of which heater is used. In FIG. 2, the variable resistor 12 for adjusting the heater resistance is provided outside the liquid nitrogen dewar 2, but it may be integrated with the liquid nitrogen dewar 2. In this case, among the heaters used, the value of the variable resistor for adjusting the heater resistance attached to the liquid nitrogen dewar combined with the heater having the highest resistance value is adjusted to zero, and the liquid is stored in the dewar. After filling with nitrogen, the variable resistor in the sample temperature variable device is adjusted so that the bridge circuit is balanced. Next, a bridge circuit is constituted by another liquid nitrogen dewar and a heater, and after filling the dewar with liquid nitrogen, a variable resistor for adjusting the heater resistance attached to the liquid nitrogen dewar is provided so that the bridge circuit is balanced. To adjust. As described above, the use of the sample temperature variable device for a magnetic resonance apparatus of the present invention makes it possible to correct a difference in resistance value between heaters even if the heater has a difference. Since the circuit can be balanced, the heater operates correctly when liquid nitrogen is in the dewar,
It is possible to provide a heater protection mechanism in which a relay circuit for stopping overheating of the heater when liquid nitrogen runs out operates properly.
【図面の簡単な説明】
【図１】 従来の実施例を示す図である。
【図２】 本発明の一実施例を示す図である。
【符号の説明】
１・・・液体窒素、２・・・液体窒素デュワー、３・・・ヒー
タ、４・・・窒素ガス、５・・・抵抗器、６・・・抵抗器、７・・・
可変抵抗器、８・・・差動増幅器、９・・・比較器、１０・・・
ドライバー、１１・・・リレー、１２・・・ヒータ抵抗調整用
可変抵抗器、Ｖd・・・ブリッジ回路のｂ−ｄ間の電圧、Ｖ
h・・・ヒータ電源電圧、Ｖs・・・基準電圧。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a conventional example. FIG. 2 is a diagram showing one embodiment of the present invention. [Description of Signs] 1 ... Liquid nitrogen, 2 ... Liquid nitrogen dewar, 3 ... Heater, 4 ... Nitrogen gas, 5 ... Resistor, 6 ... Resistor, 7 ...・
Variable resistor, 8 ... Differential amplifier, 9 ... Comparator, 10 ...
Driver, 11 ... relay 12 ... heater resistance adjusting variable resistor, the voltage between b-d of V d ... bridge circuit, V
h ··· heater power supply voltage, V s ··· reference voltage.
───────────────────────────────────────────────────── フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) G01R 33/00 - 33/64 G01N 25/00 - 25/72 F25D 3/10 H05B 3/00 310 ──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. 7 , DB name) G01R 33/00-33/64 G01N 25/00-25/72 F25D 3/10 H05B 3/00 310
Claims (1)
を加熱することによって低温の窒素ガスを気化・発生さ
せ、そのガスを試料管に吹き付けることによって試料温
度を制御するように構成すると共に、デュワー内の液体
窒素が消費されてなくなると、前記ヒータを構成要素と
して含むブリッジ回路でヒータの温度が上昇して抵抗値
が変化することに由来するバランスの崩れを検出して、
ヒータへの電力供給を断つように構成した磁気共鳴装置
用試料温度可変装置において、ヒータに直列に接続され
る可変抵抗器を設けたことを特徴とする磁気共鳴装置用
試料温度可変装置。(57) [Claims] [Claim 1] A low temperature nitrogen gas is vaporized and generated by heating a heater in liquid nitrogen stored in a dewar, and the gas is blown to a sample tube to thereby obtain a sample temperature. When the liquid nitrogen in the dewar is no longer consumed, the bridge circuit that includes the heater as a component raises the temperature of the heater and changes the resistance value, causing a loss of balance. To detect
A sample temperature variable device for a magnetic resonance apparatus, wherein a variable resistor connected in series to the heater is provided in a sample temperature variable device for a magnetic resonance apparatus configured to cut off power supply to a heater.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32607497A JP3529608B2 (en) | 1997-11-27 | 1997-11-27 | Sample temperature variable device for magnetic resonance equipment |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP32607497A JP3529608B2 (en) | 1997-11-27 | 1997-11-27 | Sample temperature variable device for magnetic resonance equipment |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH11160405A JPH11160405A (en) | 1999-06-18 |
| JP3529608B2 true JP3529608B2 (en) | 2004-05-24 |
Family
ID=18183827
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP32607497A Expired - Fee Related JP3529608B2 (en) | 1997-11-27 | 1997-11-27 | Sample temperature variable device for magnetic resonance equipment |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3529608B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007212381A (en) * | 2006-02-13 | 2007-08-23 | Jeol Ltd | Temperature control device |
-
1997
- 1997-11-27 JP JP32607497A patent/JP3529608B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH11160405A (en) | 1999-06-18 |
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