JP2003329323A - Pulse tube refrigerating machine - Google Patents

Pulse tube refrigerating machine

Info

Publication number
JP2003329323A
JP2003329323A JP2002136094A JP2002136094A JP2003329323A JP 2003329323 A JP2003329323 A JP 2003329323A JP 2002136094 A JP2002136094 A JP 2002136094A JP 2002136094 A JP2002136094 A JP 2002136094A JP 2003329323 A JP2003329323 A JP 2003329323A
Authority
JP
Japan
Prior art keywords
pulse tube
regenerator
cylinder
thickness
pressure
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
Application number
JP2002136094A
Other languages
Japanese (ja)
Inventor
Shuji Fujimoto
修二 藤本
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Daikin Industries Ltd
Original Assignee
Daikin Industries Ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Daikin Industries Ltd filed Critical Daikin Industries Ltd
Priority to JP2002136094A priority Critical patent/JP2003329323A/en
Publication of JP2003329323A publication Critical patent/JP2003329323A/en
Pending legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/14—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle
    • F25B9/145—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point characterised by the cycle used, e.g. Stirling cycle pulse-tube cycle
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/14—Compression machines, plants or systems characterised by the cycle used 
    • F25B2309/1408—Pulse-tube cycles with pulse tube having U-turn or L-turn type geometrical arrangements
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/14—Compression machines, plants or systems characterised by the cycle used 
    • F25B2309/1413—Pulse-tube cycles characterised by performance, geometry or theory
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/14—Compression machines, plants or systems characterised by the cycle used 
    • F25B2309/1414—Pulse-tube cycles characterised by pulse tube details
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/14—Compression machines, plants or systems characterised by the cycle used 
    • F25B2309/1418—Pulse-tube cycles with valves in gas supply and return lines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2309/00—Gas cycle refrigeration machines
    • F25B2309/14—Compression machines, plants or systems characterised by the cycle used 
    • F25B2309/1425—Pulse tubes with basic schematic including several pulse tubes
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B2500/00—Problems to be solved
    • F25B2500/13—Vibrations
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
    • F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
    • F25B9/00—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point
    • F25B9/10—Compression machines, plants or systems, in which the refrigerant is air or other gas of low boiling point with several cooling stages

Abstract

<P>PROBLEM TO BE SOLVED: To reduce vibration of a cooling stage and to restrain degradation of cooling performance. <P>SOLUTION: The thickness of a pulse tube cylinder 27 of a second pulse tube 4 is set larger than the thickness of a pulse tube cylinder 28 of a first pulse tube 3 (equivalent to the thickness of a normal pulse tube cylinder). By enhancing the rigidity of the cylinder 27 like this, the vibration of the cooling stage 25 caused by pulsation of pressure in the pulse tube 4 is prevented. At that time, the value of the ratio of thickness to inside diameter in the cylinder 27 is set larger than 0.05 and smaller than 0.2, so that the vibration of the cooling stage 25 is reduced to 7 μm or less, and the degradation of the refrigerating capacity is restrained. <P>COPYRIGHT: (C)2004,JPO

Description

【発明の詳細な説明】 【０００１】 【発明の属する技術分野】この発明は、パルス管冷凍機
の改良に関する。 【０００２】 【従来の技術】従来より、冷凍機として、特開２００１
‐２６３８４０号公報に開示されているようなパルス管
冷凍機がある。このパルス管冷凍機は、低温部に、ギフ
ォードマクマホン型冷凍機のディスプレーサのような可
動部分が無く構造が簡単で、振動の少ない冷凍機として
期待されている。 【０００３】上記パルス管冷凍機は、蓄冷器とパルス管
とを有している。そして、上記蓄冷器の高温端は、高圧
側バルブによって圧縮機の吐出口に接続される一方、低
圧側バルブによって上記圧縮機の吸入口に接続されてい
る。そして、この蓄冷器の低温端部には、上記パルス管
の低温端部が接続されており、上記パルス管の高温端部
にはオリフィスを介してバッファタンクが接続されてい
る。 【０００４】上記構成において、上記低圧側バルブが閉
鎖される一方、上記高圧側バルブが開放されると、上記
圧縮機から高圧の作動ガス(ヘリウムガス等)が蓄冷器に
導入されて蓄冷材と熱交換を行いつつ低温端部に至り、
パルス管の低温端部に流入する。そうすると、既にパル
ス管に存在している作動ガスが、新たに流入した作動ガ
スによって押されて高温端側に移動する。その結果、上
記パルス管内の圧力が上記バッファタンク内の圧力より
も高くなって、作動ガスがオリフィスを通ってバッファ
タンク内に流入する。 【０００５】次に、上記高圧側バルブが閉鎖される一
方、低圧側バルブが開放されると、上記蓄冷器の高温端
側の作動ガスが上記圧縮機に吸入され、それに連れてパ
ルス管内の作動ガスが蓄冷器の低温端側に流れ込み、蓄
冷材を冷却して温度上昇しつつ高温端側に移動し、圧縮
機の吸入口に戻る。その際に、上記バッファタンク内の
作動ガスがオリフィスを通ってパルス管内に戻る。 【０００６】こうして、上記パルス管内で作動ガスの圧
縮・膨張が繰り返され、その際における断熱膨張によっ
て冷熱が発生して上記蓄冷器の低温端に設けられた冷却
ステージが３０Ｋ〜８０Ｋ程度に冷却される。また、上
記蓄冷器を２段に構成し、各段夫々の蓄冷器を異なるパ
ルス管に接続した場合には、２段目の蓄冷器の冷却ステ
ージが１０Ｋ以下に冷却される。さらに、上記２段目の
蓄冷器の低温端側に極低温においても大きな比熱を有す
る磁性材料を用いた場合には、４Ｋ以下に冷却される。 【０００７】上述したように、上記従来のパルス管冷凍
機においては、パルス管内に上記ディスプレーサのよう
な可動部分は無い。したがって、振動が少なく、光学機
器等の精密機器の冷却に用いられている。 【０００８】 【発明が解決しようとする課題】しかしながら、上記従
来のパルス管冷凍機には以下のような問題がある。すな
わち、上記パルス管内では、流入・排出される作動ガス
によって圧力が低圧と高圧との間で脈動する。したがっ
て、上記パルス管の肉厚が薄い場合には数十μの範囲で
伸び縮みが生じ、パルス管の低温端に設けられた冷却ス
テージが振動することになる。このような振動は、上記
ディスプレーサの可動に起因する振動に比べて小さいと
は言うもののさらに小さいに越したことは無く、さらに
小さくすることによって、冷却対象となる精密機器によ
る計測精度の更なる向上を図ることができるのである。 【０００９】そこで、この発明の目的は、冷却ステージ
の振動をより少なくし且つ冷却性能の低下を抑制できる
パルス管冷凍機を提供することにある。 【００１０】 【課題を解決するための手段】上記目的を達成するため
に、請求項１に係る発明は、切換弁によって高圧ガス室
と低圧ガス室とに切り換え接続される蓄冷器と,この蓄
冷器に先端部が連通された１または複数のパルス管と,
各パルス管の先端部に設けられた冷却ステージを有する
パルス管冷凍機において、上記１または複数のパルス管
のうち、少なくとも最終段の蓄冷器に連通されたパルス
管におけるシリンダの肉厚と内直径との比の値を０.０
５よりも大きく且つ０.２０よりも小さくしたことを特
徴としている。 【００１１】上記構成によれば、少なくとも最終段の蓄
冷器に連通されたパルス管(以下、最終段のパルス管と
言う)におけるシリンダの肉厚と内直径との比の値が、
０.０５よりも大きくなっている。したがって、従来の
最終段のパルス管におけるシリンダよりも剛性が大きく
なって、上記最終段のパルス管内におけるガス圧の脈動
に起因する冷却ステージの振動が防止される。 【００１２】また、上記最終段のパルス管におけるシリ
ンダの肉厚と内直径との比の値が、０.２０よりも小さ
くなっている。したがって、上記最終段のパルス管にお
けるシリンダの厚肉化に伴う高温(常温)端部から低温端
部への熱伝導が抑制されて、冷凍性能の低下が防止され
る。 【００１３】 【発明の実施の形態】以下、この発明を図示の実施の形
態により詳細に説明する。図１は、本実施の形態のパル
ス管冷凍機における断面図である。 【００１４】このパルス管冷凍機は、第１蓄冷器１と、
この第１蓄冷器１の先端部に連通して直列に設けられた
第２蓄冷器２と、先端が連通管５によって第１蓄冷器１
の先端部に連通された第１パルス管３と、先端が連通管
６によって第２蓄冷器２の先端部に連通された第２パル
ス管４とを有している。そして、第１蓄冷器１,第１パ
ルス管３および第２パルス管４の基端部は、バルブ室７
の端面に取り付けられたフランジ８に挿入されて固定さ
れており、バルブ室７はモータ室９に固定されている。
ここで、第１蓄冷器１内にはメッシュ状の蓄冷材１０
(一部のみ図示)が積層されて充填され、第２蓄冷器２内
には球状の蓄冷材１１(一部のみ図示)が充填されてい
る。 【００１５】上記バルブ室７には、ロータとステータと
で構成される切換弁１２が設けられており、モータ室９
に設けられた駆動モータ１３によって切換弁１２の上記
ロータを回転駆動することによって、第１蓄冷器１の基
端部が、通路１４を介して、導入口１５を有する高圧室
１６と排出口１７を有する低圧室１８とに切り換え連通
される。尚、駆動モータ１３は高圧室１６内に収納され
ており、導入口１５は圧縮機１９の吐出口に接続されて
おり、排出口１７は圧縮機１９の吸入口に接続されてい
る。 【００１６】また、上記第１パルス管３の基端部は、第
１流路抵抗２０が介設された流路によって通路１４に連
通されている。更に、第１パルス管３の基端部は、第２
流路抵抗２１が介設された流路によってバッファタンク
２２に連通されている。尚、図１では省略されている
が、第２パルス管４の基端部も同様に、流路抵抗が介設
された流路によって通路１４とバッファタンク２２とに
連通されている。 【００１７】上記構成を有するパルス管冷凍機は、上記
駆動モータ１３によって切換弁１２を回転して、第１蓄
冷器１の基端部を高圧室１６と低圧室１８とに切り換え
接続することによって、上記従来のパルス管冷凍機の場
合と同様にして、第１パルス管３内で作動ガスが圧縮と
膨張とを繰り返し、その際における断熱膨張によって発
生する冷熱によって、第１蓄冷器１の先端部に設けられ
たシールド冷却ステージ２３および第１パルス管３の先
端部に設けられた冷却ステージ２４が３０Ｋ〜８０Ｋ程
度に冷却される。 【００１８】さらに、本パルス管冷凍機の蓄冷器は２段
に構成されているため、上記高圧室１６から第１蓄冷器
１内に導入された高圧作動ガスは、第１蓄冷器１の先端
から第２蓄冷器２の基端部に導入される。そして、第２
蓄冷器２の蓄冷材１１と熱交換を行いつつ先端部に至
り、連通管６を通って第２パルス管４の先端部に流入す
る。そうすると、既に第２パルス管４に存在している作
動ガスが、新たに流入した作動ガスによって押されて基
端側に移動し始める。同時に、第１流路抵抗を通って第
２パルス管４の基端部に作動ガスが流入し、第２パルス
管４の先端部から流入する作動ガスが抑制される。その
結果、作動ガスの移動のタイミングが第２パルス管４内
における圧力変化のタイミングに対して遅れる。その
後、第２パルス管４内の圧力がバッファタンク２２内の
圧力よりも高くなって基端側の作動ガスが第２流路抵抗
を通ってバッファタンク２２内に流入し、第２パルス管
４内の作動ガスが基端側に移動する。 【００１９】次に、上記第１蓄冷器１が低圧室１８に切
り換え接続されると、上記第１蓄冷器１内の減圧に伴っ
て第２蓄冷器２内の作動ガスが第１蓄冷器１に吸入され
始める。そうすると、既に第２パルス管４に存在してい
る作動ガスが、第２蓄冷器２に吸入され、第２パルス管
４内の作動ガスが低温端側に移動し始める。同時に、第
１流路抵抗を通って第２パルス管４の基端側の作動ガス
が流出し、第２パルス管４の先端部から流出する作動ガ
スが抑制される。その後、バッファタンク２２内の作動
ガスが第２流路抵抗を通って第２パルス管４内に戻ると
共に、第２パルス管４内の作動ガスが第２蓄冷器２の低
温端側に流れ込み、蓄冷材１１を冷却して温度上昇しつ
つ高温端側に移動し、第１蓄冷器１を介して圧縮機１９
の吸入口に戻る。 【００２０】こうして、上記第２パルス管４内におい
て、第１パルス管３によって８０Ｋ程度に冷却された作
動ガスの圧縮・膨張が繰り返され、その際における断熱
膨張によって発生した冷熱によって、第２パルス管４の
先端部に設けられた冷却ステージ２５および第２蓄冷器
２の先端部に設けられたシールド冷却ステージ２６が４
Ｋ程度に冷却されるのである。 【００２１】ここで、本実施の形態においては、上記第
２パルス管４のパルス管シリンダ２７の肉厚を、上記第
１パルス管３のパルス管シリンダ２８の肉厚(通常のパ
ルス管シリンダの肉厚と同等)よりも厚くしている。こ
うして、パルス管シリンダ２７の剛性を高めることによ
って、第２パルス管４内における圧力の脈動に起因する
冷却ステージ２５の振動を防止するのである。 【００２２】一方において、上記第２パルス管４のパル
ス管シリンダ２７の肉厚を厚くし過ぎると、パルス管シ
リンダ２７の熱伝導性が良くなり高温端(基端)部から低
温側(先端側)への伝導熱が大きくなる。そのために冷凍
性能が低下することになる。 【００２３】図２は、パルス管シリンダの肉厚と当該パ
ルス管シリンダの内直径との比(以下、肉厚/内径比と言
う)と、温度が４.２Ｋ時における冷凍能力および上記パ
ルス管シリンダ先端の変位(振動)との関係を示す。尚、
その場合にパルス管内に掛る低圧時における作動ガス圧
は１０気圧であり、高圧時における作動ガス圧は２０気
圧であり、一般的なパルス管冷凍機の場合と同等であ
る。図２から明らかなように、上記パルス管シリンダの
肉厚/内径比の値が０.０５以下になると先端の変位が急
激に増加して７μm以上になる。また、上記パルス管シ
リンダの肉厚/内径比の値が０.２以上になると、上記冷
凍能力が０.１６ワット以下に減少する。 【００２４】そこで、本実施の形態においては、上記第
２パルス管４のパルス管シリンダ２７における肉厚/内
径比の値を、０.０５よりも大きく且つ０.２よりも小さ
く設定するのである。こうすることによって、冷却ステ
ージ２５の振動を７μmよりも小さくして、従来のパル
ス管冷凍機における振動よりも大幅に低減することがで
きる。また、パルス管シリンダ２７の肉厚増加による冷
凍能力の低下を抑制することによって、第２パルス管４
における４.２Ｋ時の冷凍能力を０.１６ワットよりも大
きくすることができるのである。 【００２５】したがって、本実施の形態におけるパルス
管冷凍機によれば、冷却ステージ２５の振動を７μmよ
りも小さくすることができ、冷却ステージ２５に取り付
けられる光学機器等の精密機器に対する振動の影響を小
さくして、上記精密機器による計測精度を従来のパルス
管冷凍機よりも大幅に向上できるのである。 【００２６】尚、上記実施の形態においては、上記第２
パルス管４のパルス管シリンダ２７のみにこの発明を適
用しているが、１段目の第１パルス管３のパルス管シリ
ンダ２８にも適用しても一向に構わない。要は、少なく
とも、冷却の対象となる精密機器が直接取り付けられる
最終段のパルス管のパルス管シリンダ２７に適用されて
いれば良いのである。 【００２７】また、上記実施の形態においては、上記第
１蓄冷器１および第１パルス管３と第２蓄冷器２および
第２パルス管４とで成る２段のパルス管冷凍機の場合を
例に説明しているが、３段以上のパルス管冷凍機にも適
用できることは言うまでもない。その場合にも、少なく
とも、最終段のパルス管のパルス管シリンダにこの発明
を適用すれば良いのである。 【００２８】 【発明の効果】以上より明らかなように、請求項１に係
る発明のパルス管冷凍機は、少なくとも最終段の蓄冷器
に連通された最終段のパルス管におけるシリンダの肉厚
と内直径との比の値を、０.０５よりも大きくしてい
る。したがって、従来の最終段のパルス管におけるシリ
ンダよりも剛性を大きくして、上記最終段のパルス管内
におけるガス圧の脈動に起因する冷却ステージの振動を
従来のパルス管冷凍機よりも少なくできる。 【００２９】また、上記最終段のパルス管におけるシリ
ンダの肉厚と内直径との比の値を、０.２０よりも小さ
くしている。したがって、上記最終段のパルス管におけ
るシリンダの厚肉化に伴う高温端部から低温側への熱伝
導を抑制でき、冷凍性能の低下を防止できる。 【００３０】すなわち、この発明によれば、光学機器等
の精密機器の冷却に最適なパルス管冷凍機を提供できる
のである。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a pulse tube refrigerator. 2. Description of the Related Art Conventionally, a refrigerator has been disclosed in JP-A-2001-2001.
There is a pulse tube refrigerator as disclosed in JP-A-263840. This pulse tube refrigerator is expected to be a refrigerator having a simple structure without a movable part such as a displacer of a Gifford McMahon type refrigerator in a low temperature part and having less vibration. [0003] The pulse tube refrigerator has a regenerator and a pulse tube. The high-temperature end of the regenerator is connected to a discharge port of the compressor by a high-pressure valve, and is connected to a suction port of the compressor by a low-pressure valve. The low-temperature end of the regenerator is connected to the low-temperature end of the pulse tube, and the high-temperature end of the pulse tube is connected to a buffer tank via an orifice. In the above structure, when the low-pressure side valve is closed while the high-pressure side valve is opened, a high-pressure working gas (helium gas or the like) is introduced from the compressor into the regenerator to recharge the regenerator material. It reaches the low temperature end while performing heat exchange,
It flows into the cold end of the pulse tube. Then, the working gas already existing in the pulse tube is pushed by the newly flowing working gas and moves to the high temperature end side. As a result, the pressure in the pulse tube becomes higher than the pressure in the buffer tank, and the working gas flows into the buffer tank through the orifice. Next, when the high-pressure side valve is closed and the low-pressure side valve is opened, the working gas at the high-temperature end of the regenerator is sucked into the compressor, and the working gas in the pulse tube is accordingly operated. The gas flows into the low-temperature end of the regenerator, cools the regenerator material, moves to the high-temperature end while increasing the temperature, and returns to the suction port of the compressor. At that time, the working gas in the buffer tank returns to the pulse tube through the orifice. [0006] Thus, the compression and expansion of the working gas are repeated in the pulse tube. At that time, adiabatic expansion generates cold heat, and the cooling stage provided at the low temperature end of the regenerator is cooled to about 30K to 80K. You. Further, when the regenerator is configured in two stages and each regenerator is connected to a different pulse tube, the cooling stage of the second regenerator is cooled to 10K or less. Further, when a magnetic material having a large specific heat even at an extremely low temperature is used on the low temperature end side of the second stage regenerator, the regenerator is cooled to 4K or less. As described above, in the conventional pulse tube refrigerator, there is no movable part such as the displacer in the pulse tube. Therefore, it has little vibration and is used for cooling precision equipment such as optical equipment. However, the above-mentioned conventional pulse tube refrigerator has the following problems. That is, in the pulse tube, the pressure pulsates between a low pressure and a high pressure due to the working gas flowing in and out. Therefore, when the thickness of the pulse tube is small, the pulse tube expands and contracts in a range of several tens of microns, and the cooling stage provided at the low-temperature end of the pulse tube vibrates. Although such vibrations are smaller than the vibrations caused by the movement of the displacer, they are not much smaller, and by further reducing the vibrations, the accuracy of measurement by precision equipment to be cooled is further improved. Can be achieved. SUMMARY OF THE INVENTION It is an object of the present invention to provide a pulse tube refrigerator capable of reducing the vibration of a cooling stage and suppressing a decrease in cooling performance. [0010] In order to achieve the above object, the invention according to claim 1 is directed to a regenerator connected to a high-pressure gas chamber and a low-pressure gas chamber by a switching valve, and a regenerator for the regenerator. One or more pulse tubes, the tips of which are connected to the vessel,
In a pulse tube refrigerator having a cooling stage provided at the tip of each pulse tube, the wall thickness and inner diameter of the cylinder in at least the pulse tube connected to the last stage regenerator among the one or more pulse tubes And the value of the ratio to 0.0
It is characterized in that it is larger than 5 and smaller than 0.20. According to the above configuration, at least the value of the ratio between the wall thickness and the inner diameter of the cylinder in the pulse tube (hereinafter referred to as the last stage pulse tube) connected to the last stage regenerator is:
It is larger than 0.05. Therefore, the rigidity is higher than that of the cylinder in the conventional last stage pulse tube, and the vibration of the cooling stage due to the pulsation of the gas pressure in the last stage pulse tube is prevented. Further, the value of the ratio between the thickness and the inner diameter of the cylinder in the last-stage pulse tube is smaller than 0.20. Therefore, heat conduction from the high-temperature (normal temperature) end to the low-temperature end due to the thickening of the cylinder in the last-stage pulse tube is suppressed, and a decrease in refrigeration performance is prevented. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the illustrated embodiments. FIG. 1 is a sectional view of a pulse tube refrigerator according to the present embodiment. This pulse tube refrigerator has a first regenerator 1
A second regenerator 2 connected in series with the tip of the first regenerator 1 and a first regenerator 1 connected by a communication tube 5 at the tip.
And a second pulse tube 4 having a distal end communicated with the distal end of the second regenerator 2 by a communication tube 6. The base ends of the first regenerator 1, the first pulse tube 3, and the second pulse tube 4 are connected to the valve chamber 7
The valve chamber 7 is fixed to the motor chamber 9 by being inserted into and fixed to a flange 8 attached to the end face of the motor.
Here, a mesh-shaped cold storage material 10 is provided in the first regenerator 1.
The second regenerator 2 is filled with a spherical regenerator material 11 (only a part is shown). The valve chamber 7 is provided with a switching valve 12 composed of a rotor and a stator.
When the rotor of the switching valve 12 is rotationally driven by the drive motor 13 provided in the first regenerator 1, the base end of the first regenerator 1 is connected to the high pressure chamber 16 having the inlet 15 and the discharge port 17 through the passage 14. And is communicated to the low-pressure chamber 18 having The drive motor 13 is housed in the high-pressure chamber 16, the inlet 15 is connected to the outlet of the compressor 19, and the outlet 17 is connected to the inlet of the compressor 19. A base end of the first pulse tube 3 is communicated with the passage 14 by a flow path in which a first flow path resistance 20 is provided. Further, the base end of the first pulse tube 3 is
A flow path resistor 21 is communicated with the buffer tank 22 by a flow path provided. Although not shown in FIG. 1, the base end of the second pulse tube 4 is similarly connected to the passage 14 and the buffer tank 22 by a flow path provided with flow resistance. In the pulse tube refrigerator having the above structure, the switching valve 12 is rotated by the drive motor 13 to switch and connect the base end of the first regenerator 1 to the high-pressure chamber 16 and the low-pressure chamber 18. As in the case of the above-described conventional pulse tube refrigerator, the working gas repeatedly compresses and expands in the first pulse tube 3, and the cold generated by adiabatic expansion at that time causes the tip of the first regenerator 1. The shield cooling stage 23 provided at the section and the cooling stage 24 provided at the tip of the first pulse tube 3 are cooled to about 30K to 80K. Further, since the regenerator of the pulse tube refrigerator is configured in two stages, the high-pressure working gas introduced into the first regenerator 1 from the high-pressure chamber 16 is supplied to the tip of the first regenerator 1. From the second regenerator 2 to the base end. And the second
The heat reaches the distal end portion while performing heat exchange with the cold storage material 11 of the regenerator 2, and flows into the distal end portion of the second pulse tube 4 through the communication pipe 6. Then, the working gas already existing in the second pulse tube 4 is pushed by the newly flowing working gas and starts to move to the proximal end side. At the same time, the working gas flows into the base end of the second pulse tube 4 through the first flow path resistance, and the working gas flowing from the front end of the second pulse tube 4 is suppressed. As a result, the timing of the movement of the working gas is delayed with respect to the timing of the pressure change in the second pulse tube 4. After that, the pressure in the second pulse tube 4 becomes higher than the pressure in the buffer tank 22, and the working gas on the base end side flows into the buffer tank 22 through the second flow path resistance. The working gas inside moves to the proximal end side. Next, when the first regenerator 1 is switched and connected to the low-pressure chamber 18, the working gas in the second regenerator 2 is discharged with the pressure reduction in the first regenerator 1. Begins to be inhaled. Then, the working gas already existing in the second pulse tube 4 is sucked into the second regenerator 2, and the working gas in the second pulse tube 4 starts to move to the low-temperature end side. At the same time, the working gas at the base end of the second pulse tube 4 flows out through the first flow path resistance, and the working gas flowing out from the distal end of the second pulse tube 4 is suppressed. Thereafter, the working gas in the buffer tank 22 returns to the second pulse tube 4 through the second flow path resistance, and the working gas in the second pulse tube 4 flows into the low-temperature end of the second regenerator 2, The cool storage material 11 is cooled and moved to the high-temperature end side while increasing the temperature.
Return to the inlet. Thus, in the second pulse tube 4, the compression and expansion of the working gas cooled to about 80K by the first pulse tube 3 are repeated, and the second pulse is generated by the cold generated by the adiabatic expansion at that time. The cooling stage 25 provided at the tip of the tube 4 and the shield cooling stage 26 provided at the tip of the second regenerator 2
It is cooled to about K. In the present embodiment, the thickness of the pulse tube cylinder 27 of the second pulse tube 4 is set to the thickness of the pulse tube cylinder 28 of the first pulse tube 3 (the thickness of the ordinary pulse tube cylinder). (Equivalent to wall thickness). Thus, by increasing the rigidity of the pulse tube cylinder 27, vibration of the cooling stage 25 due to pressure pulsation in the second pulse tube 4 is prevented. On the other hand, if the thickness of the pulse tube cylinder 27 of the second pulse tube 4 is too large, the heat conductivity of the pulse tube cylinder 27 is improved, and the high temperature end (base end) is shifted to the low temperature side (distal end side). ) Increases the conduction heat. Therefore, the refrigerating performance is reduced. FIG. 2 shows the ratio between the thickness of the pulse tube cylinder and the inner diameter of the pulse tube cylinder (hereinafter referred to as the thickness / inner diameter ratio), the refrigerating capacity at a temperature of 4.2 K, and the pulse tube. This shows the relationship with the displacement (vibration) of the cylinder tip. still,
In this case, the working gas pressure at low pressure applied to the pulse tube is 10 atm, and the working gas pressure at high pressure is 20 atm, which is equivalent to that of a general pulse tube refrigerator. As is apparent from FIG. 2, when the value of the thickness / inner diameter ratio of the pulse tube cylinder becomes 0.05 or less, the displacement of the tip sharply increases and becomes 7 μm or more. Also, when the value of the thickness / inner diameter ratio of the pulse tube cylinder becomes 0.2 or more, the refrigeration capacity decreases to 0.16 watts or less. Therefore, in this embodiment, the value of the thickness / inner diameter ratio of the second pulse tube 4 in the pulse tube cylinder 27 is set to be larger than 0.05 and smaller than 0.2. . By doing so, the vibration of the cooling stage 25 can be made smaller than 7 μm, and can be significantly reduced as compared with the vibration in the conventional pulse tube refrigerator. Further, by suppressing a decrease in the refrigerating capacity due to an increase in the thickness of the pulse tube cylinder 27, the second pulse tube 4
The refrigerating capacity at 4.2K in the above can be made larger than 0.16 watts. Therefore, according to the pulse tube refrigerator of the present embodiment, the vibration of the cooling stage 25 can be made smaller than 7 μm, and the influence of the vibration on the precision equipment such as the optical equipment attached to the cooling stage 25 can be reduced. By reducing the size, the precision of measurement by the precision equipment can be greatly improved as compared with the conventional pulse tube refrigerator. In the above embodiment, the second
Although the present invention is applied only to the pulse tube cylinder 27 of the pulse tube 4, it may be applied to the pulse tube cylinder 28 of the first pulse tube 3 of the first stage. In short, it is sufficient that the present invention is applied to at least the pulse tube cylinder 27 of the last stage pulse tube to which the precision equipment to be cooled is directly attached. In the above-described embodiment, a two-stage pulse tube refrigerator including the first regenerator 1 and the first pulse tube 3 and the second regenerator 2 and the second pulse tube 4 is exemplified. However, it goes without saying that the present invention can also be applied to a pulse tube refrigerator having three or more stages. In such a case, at least, the present invention may be applied to the pulse tube cylinder of the last stage pulse tube. As is apparent from the above description, the pulse tube refrigerator according to the first aspect of the present invention has at least the thickness and inner thickness of the cylinder in the last pulse tube connected to the last regenerator. The value of the ratio to the diameter is set to be larger than 0.05. Therefore, the rigidity of the cylinder in the conventional last stage pulse tube is made larger than that of the cylinder, and the vibration of the cooling stage caused by the pulsation of the gas pressure in the last stage pulse tube can be reduced as compared with the conventional pulse tube refrigerator. The value of the ratio between the wall thickness and the inner diameter of the cylinder in the last stage pulse tube is set to be smaller than 0.20. Therefore, heat conduction from the high-temperature end to the low-temperature side due to the thickening of the cylinder in the last-stage pulse tube can be suppressed, and a decrease in refrigeration performance can be prevented. That is, according to the present invention, it is possible to provide a pulse tube refrigerator optimal for cooling precision equipment such as optical equipment.

【図面の簡単な説明】 【図１】 この発明のパルス管冷凍機における断面図で
ある。 【図２】 パルス管シリンダの肉厚/内径比と冷凍能力
および先端変位との関係を示す図である。 【符号の説明】 １…第１蓄冷器、 ２…第２蓄冷器、 ３…第１パルス管、 ４…第２パルス管、 ５,６…連通管、 ８…フランジ、 １０,１１…蓄冷材、 １２…切換弁、 １３…駆動モータ、 １６…高圧室、 １８…低圧室、 １９…圧縮機、 ２０,２１…流路抵抗、 ２２…バッファタンク、 ２４,２５…冷却ステージ、 ２７,２８…パルス管シリンダ。BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a pulse tube refrigerator according to the present invention. FIG. 2 is a diagram showing a relationship between a thickness / inner diameter ratio of a pulse tube cylinder, a refrigerating capacity and a tip displacement. [Description of Signs] 1 ... first regenerator, 2 ... second regenerator, 3 ... first pulse tube, 4 ... second pulse tube, 5,6 ... communication tube, 8 ... flange, 10,11 ... cool storage material , 12 switching valve, 13 drive motor, 16 high pressure chamber, 18 low pressure chamber, 19 compressor, 20, 21 flow path resistance, 22 buffer buffer, 24, 25 cooling stage, 27, 28 Pulse tube cylinder.

Claims (1)

【特許請求の範囲】 【請求項１】 切換弁(１２)によって高圧ガス室(１６)
と低圧ガス室(１８)とに切り換え接続される蓄冷器(１,
２)と、この蓄冷器(１,２)に先端部が連通された１また
は複数のパルス管(３,４)と、各パルス管(３,４)の先端
部に設けられた冷却ステージ(２４,２５)を有するパル
ス管冷凍機において、 上記１または複数のパルス管(３,４)のうち、少なくと
も最終段の蓄冷器(２)に連通されたパルス管(４)におけ
るシリンダ(２７)の肉厚と内直径との比の値を０.０５
よりも大きく且つ０.２０よりも小さくしたことを特徴
とするパルス管冷凍機。Claims: 1. A high-pressure gas chamber (16) by a switching valve (12).
And a regenerator (1,
2), one or a plurality of pulse tubes (3, 4) whose tips communicate with the regenerators (1, 2), and a cooling stage (3, 4) provided at the tip of each pulse tube (3, 4). 24, 25), wherein the cylinder (27) in the pulse tube (4) communicated with at least the last stage regenerator (2) of the one or more pulse tubes (3, 4). The value of the ratio of the wall thickness to the inner diameter is 0.05
A pulse tube refrigerator characterized by being larger than 0.20 and smaller than 0.20.
JP2002136094A 2002-05-10 2002-05-10 Pulse tube refrigerating machine Pending JP2003329323A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002136094A JP2003329323A (en) 2002-05-10 2002-05-10 Pulse tube refrigerating machine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2002136094A JP2003329323A (en) 2002-05-10 2002-05-10 Pulse tube refrigerating machine

Publications (1)

Publication Number Publication Date
JP2003329323A true JP2003329323A (en) 2003-11-19

Family

ID=29698243

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2002136094A Pending JP2003329323A (en) 2002-05-10 2002-05-10 Pulse tube refrigerating machine

Country Status (1)

Country Link
JP (1) JP2003329323A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013175168A2 (en) * 2012-05-25 2013-11-28 Oxford Instruments Nanotechnology Tools Limited Apparatus for reducing vibrations in a pulse tube refrigerator such as for magentic resonance imaging systems

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013175168A2 (en) * 2012-05-25 2013-11-28 Oxford Instruments Nanotechnology Tools Limited Apparatus for reducing vibrations in a pulse tube refrigerator such as for magentic resonance imaging systems
WO2013175168A3 (en) * 2012-05-25 2014-01-30 Oxford Instruments Nanotechnology Tools Limited Apparatus for reducing vibrations in a pulse tube refrigerator such as for magentic resonance imaging systems
JP2015523533A (en) * 2012-05-25 2015-08-13 オックスフォード インストルメンツ ナノテクノロジー ツールス リミテッド Device for reducing vibration of pulse tube refrigerators used in magnetic resonance diagnostic imaging equipment
US10162023B2 (en) 2012-05-25 2018-12-25 Oxford Instruments Nanotechnology Tools Limited Apparatus for reducing vibrations in a pulse tube refrigerator such as for magnetic resonance imaging systems

Similar Documents

Publication Publication Date Title
JP4147697B2 (en) Pulse tube refrigerator
JP4617251B2 (en) Coaxial multistage pulse tube for helium recondensation.
TW201226704A (en) Cryopump and cryogenic refrigerator
JP3702964B2 (en) Multistage low temperature refrigerator
JPH0611200A (en) Cryogenic refrigerating machine
JP2003329323A (en) Pulse tube refrigerating machine
JP2609327B2 (en) refrigerator
JP2003194428A (en) Cooling device
JP3793481B2 (en) Pulse tube refrigerator
EP1503154B1 (en) Stirling/pulse tube hybrid cryocooler with gas flow shunt
JP2000035253A (en) Cooler
US7305835B2 (en) Pulse tube cooling by circulation of buffer gas
JP2001248927A (en) Low-temperature device using pulse tube refrigeration unit
JP2723342B2 (en) Cryogenic refrigerator
JP3883903B2 (en) Pulse tube refrigerator
JP2003329325A (en) Cold storage unit mounting structure of pulse tube refrigerating machine
JP2001317827A (en) Cryogenic refrigerating machine
JPH0674584A (en) Cryogenic refrigerator and operating method thereof
JP2003329321A (en) Pulse tube refrigerating machine
KR101421045B1 (en) Pulse tube refrigerator having gas storage unit to which heat exchanger is attached
JPH08313095A (en) Cold storage type refrigerating machine
JP2001248930A (en) Cryogenic refrigeration unit
JP2002286312A (en) Pulse tube refrigerating machine
KR100571128B1 (en) Pulse tube refrigerator using two-way linear compressor
JP2880154B1 (en) Pulse tube refrigerator

Legal Events

Date Code Title Description
A711 Notification of change in applicant

Effective date: 20040329

Free format text: JAPANESE INTERMEDIATE CODE: A711

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A821

Effective date: 20040819

A621 Written request for application examination

Free format text: JAPANESE INTERMEDIATE CODE: A621

Effective date: 20040819

RD02 Notification of acceptance of power of attorney

Free format text: JAPANESE INTERMEDIATE CODE: A7422

Effective date: 20040819

A977 Report on retrieval

Effective date: 20060130

Free format text: JAPANESE INTERMEDIATE CODE: A971007

A131 Notification of reasons for refusal

Free format text: JAPANESE INTERMEDIATE CODE: A131

Effective date: 20060207

A521 Written amendment

Free format text: JAPANESE INTERMEDIATE CODE: A523

Effective date: 20060404

A02 Decision of refusal

Effective date: 20060905

Free format text: JAPANESE INTERMEDIATE CODE: A02