JP2633581B2 - Heat exchanger for refrigerator - Google Patents
Heat exchanger for refrigeratorInfo
- Publication number
- JP2633581B2 JP2633581B2 JP62241354A JP24135487A JP2633581B2 JP 2633581 B2 JP2633581 B2 JP 2633581B2 JP 62241354 A JP62241354 A JP 62241354A JP 24135487 A JP24135487 A JP 24135487A JP 2633581 B2 JP2633581 B2 JP 2633581B2
- Authority
- JP
- Japan
- Prior art keywords
- low
- heat exchanger
- heat
- pipe
- 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.)
- Expired - Lifetime
Links
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- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
Description
【発明の詳細な説明】 ［発明の目的］ （産業上の利用分野） 本発明は、小型ヘリウム冷凍機に用いるのに好適な冷
凍機用熱交換器に係り、特に、圧力損失を抑制した状態
で低圧側の熱伝達を向上させた冷凍機用熱交換器に関す
る。Description: Object of the Invention (Industrial application field) The present invention relates to a heat exchanger for a refrigerator suitable for use in a small helium refrigerator, and particularly to a state in which pressure loss is suppressed. The present invention relates to a heat exchanger for a refrigerator having improved heat transfer on the low pressure side.
（従来の技術） MRI等の超電導マグネットを冷却するには小型のヘリ
ウム冷凍機が必要である。小型ヘリウム冷凍機は、通
常、予冷用のヘリウム冷凍機とジュール・トムソン（J
T）ラインとを備えており、5K近くまで冷却された高圧
のガスヘリウムをJT弁で膨脹して液体ヘリウム温度を得
ている。JTラインには、高圧のガスヘリウムと膨脹した
ガスヘリウムとを熱交換させる熱交換器が複数個備えら
れている。(Conventional technology) A small helium refrigerator is required to cool a superconducting magnet such as an MRI. Small helium refrigerators are usually pre-cooled helium refrigerators and Joule Thomson (J
T) line, and high-pressure gas helium cooled to near 5K is expanded by a JT valve to obtain liquid helium temperature. The JT line is provided with a plurality of heat exchangers for exchanging heat between high-pressure gas helium and expanded gas helium.
ところで、このように極低温で用いられる冷凍機用熱
交換器には非常に高い熱交換効率（95％以上）が要求さ
れる。すなわち、熱交換器の損失分は予冷用のヘリウム
冷凍機によって冷却せねばならない。したがって損失の
増大は予冷用冷凍機の大型化を招き、ひいてはシステム
全体の大型化につながる。また、それに伴い入力のパワ
ーも増大してしまう。したがって冷凍機の小型化と高効
率化を図るには、熱交換器の高効率化と小型化を図る必
要がある。By the way, extremely high heat exchange efficiency (95% or more) is required for a heat exchanger for a refrigerator used at such a very low temperature. That is, the loss of the heat exchanger must be cooled by a helium refrigerator for pre-cooling. Therefore, an increase in loss leads to an increase in the size of the pre-cooling refrigerator, which in turn leads to an increase in the size of the entire system. In addition, the input power also increases accordingly. Therefore, in order to reduce the size and efficiency of the refrigerator, it is necessary to increase the efficiency and size of the heat exchanger.
今、熱交換器のNTU（Number of Transfer Unit）と熱
交換器の温度効率εとの関係を簡略化すると、 で表される。ここで、 m:質量流量、Cp:定圧比熱、U:熱通過率、 A:伝熱面積 である。第２図にNTUとεとの関係を示す。図から明ら
かなように、εが上がるにつれ、NTUを大きくする必要
があり、しかも要求される範囲（ε＞95％）ではNTUを
著しく大きくしなければならない。Now, if the relationship between the heat exchanger NTU (Number of Transfer Unit) and the heat exchanger temperature efficiency ε is simplified, It is represented by here, m: mass flow rate, Cp: constant pressure specific heat, U: heat transmittance, A: heat transfer area. FIG. 2 shows the relationship between NTU and ε. As is clear from the figure, the NTU needs to be increased as ε increases, and the NTU must be significantly increased in the required range (ε> 95%).
NTUの中で、ｍ及びCpは不変であるから、熱通過率Ｕ
及び伝熱面積Ａを大きくすることが必要である。Ｕは簡
単に hi:高圧側熱伝達率、ho:低圧側熱伝達率 λ：母材の熱伝導率、δ：母材の厚さ と表わせる。右辺の３項の内、δ／λは通常他の２項に
比べて十分小さいため、NTUを増やすには、高・低圧の
熱伝達率及び伝熱面積を増やさなければならない。しか
し、伝熱面積の増加は一般に圧力損失の増大を引起こ
す。熱交換器に生じる圧力損失は、システム全体の性能
に大きな影響を与える。特に、低圧側の圧力損失はJT膨
脹した後のガスヘリウム温度の上昇を招く。たとえば、
コンプレッサの低圧側吸入口の圧力が1atmとして、熱交
換器低圧側の圧力損失が０とすると、JT膨脹後の圧力は
1atmであり、そこでの温度は1atmの飽和温度4.224Kとな
る。しかしながら、圧力損失が0.2あるいは0.4atmと増
加するとJT膨脹後の圧力は、それぞれ1.2および1.4atm
となり、それに伴い温度も4.424および4.602Kと上昇し
てしまう。したがって、低圧側の圧力損失を極力抑える
ことが必要である。In the NTU, m and Cp are invariable, so that the heat transfer rate U
In addition, it is necessary to increase the heat transfer area A. U is easy hi: heat transfer coefficient on high pressure side, ho: heat transfer coefficient on low pressure side λ: thermal conductivity of base material, δ: thickness of base material Of the three terms on the right-hand side, δ / λ is usually much smaller than the other two terms, so to increase the NTU, the heat transfer coefficient and the heat transfer area at high and low pressures must be increased. However, an increase in the heat transfer area generally causes an increase in pressure loss. The pressure loss that occurs in the heat exchanger has a significant effect on the performance of the entire system. In particular, the pressure loss on the low pressure side causes the gas helium temperature to rise after JT expansion. For example,
Assuming that the pressure on the low pressure side suction port of the compressor is 1 atm and the pressure loss on the low pressure side of the heat exchanger is 0, the pressure after JT expansion is
It is 1 atm, and the temperature there is a saturation temperature of 1 atm of 4.224K. However, when the pressure loss increases to 0.2 or 0.4 atm, the pressure after JT expansion becomes 1.2 and 1.4 atm, respectively.
And the temperature rises accordingly to 4.424 and 4.602K. Therefore, it is necessary to minimize the pressure loss on the low pressure side.
第３図は従来の冷凍機用熱交換器を模式的に示すもの
である。図中１は熱交換器外筒を示し、２は高圧側配管
を示している。高圧側配管２は銅などで形成されてお
り、スパイラル状に巻かれて熱交換器外筒１に収められ
ている。熱交換器外筒１の両端面には端板1aが溶接され
ており、これから高圧側配管入口３、出口４と低圧側配
管入口５、出口６とが導かれている。高圧のガスヘリウ
ムは高圧側配管入口３から入り、高圧側配管２内を通っ
て高圧側配管出口４から出る。低圧のガスヘリウムは低
圧側入口５から入り、熱交換器外筒１と高圧側配管２の
間を通り低圧側配管出口６から出る。このとき、高低圧
のガスヘリウムはそれぞれ高圧側配管２の管壁を介して
熱交換する。FIG. 3 schematically shows a conventional heat exchanger for a refrigerator. In the drawing, reference numeral 1 denotes a heat exchanger outer cylinder, and reference numeral 2 denotes a high-pressure side pipe. The high-pressure side pipe 2 is formed of copper or the like, and is wound in a spiral shape and housed in the heat exchanger outer cylinder 1. End plates 1 a are welded to both end surfaces of the heat exchanger outer cylinder 1, and lead to a high-pressure side pipe inlet 3 and an outlet 4 and a low-pressure side pipe inlet 5 and an outlet 6. The high-pressure gas helium enters through the high-pressure pipe inlet 3, passes through the high-pressure pipe 2, and exits through the high-pressure pipe outlet 4. Low-pressure gas helium enters through the low-pressure side inlet 5, passes between the heat exchanger outer cylinder 1 and the high-pressure side pipe 2, and exits through the low-pressure side pipe outlet 6. At this time, the high and low pressure gas helium exchanges heat via the pipe wall of the high pressure side pipe 2 respectively.
このような冷凍機用熱交換器において、前述した理由
で、低圧側の圧力損失を極力低減するために、低圧側の
流路断面積を増して流速を落とすと低圧側の熱伝達率は
減少してしまうことになる。そこで、低圧側の伝熱面積
を増加させるために高圧側配管２の外面にフィン等を設
けることが考えられるが、このようにすると、熱交換器
の大型化につながることになる。このように、従来の小
型の冷凍機用熱交換器においては、低圧側の圧力損失を
抑えて熱伝達を高めることが非常に困難であった。In such a heat exchanger for a refrigerator, the heat transfer coefficient on the low-pressure side decreases when the cross-sectional area of the flow path on the low-pressure side is increased and the flow velocity is decreased to minimize the pressure loss on the low-pressure side for the reason described above. Will be done. Therefore, it is conceivable to provide fins or the like on the outer surface of the high-pressure side pipe 2 in order to increase the heat transfer area on the low-pressure side. However, this leads to an increase in the size of the heat exchanger. As described above, in the conventional small heat exchangers for refrigerators, it has been extremely difficult to suppress the pressure loss on the low pressure side and enhance the heat transfer.
（発明が解決しようとする問題点） 上述のように、従来の冷凍機用熱交換器にあっては、
所定の性能を発揮させようとする低圧側の熱伝達を増加
させねばならず、そのためには圧力損失の増大や熱交換
器本体の大型化を招く欠点があった。(Problems to be solved by the invention) As described above, in the conventional heat exchanger for refrigerators,
It is necessary to increase the heat transfer on the low-pressure side in order to achieve a predetermined performance, and this has the disadvantage of increasing the pressure loss and increasing the size of the heat exchanger body.
そこで本発明は簡単な構成であるにも拘らず、圧力損
失を抑えたまま低圧側の伝熱面積と熱伝達率を飛躍的に
増加させ、もって高効率で小型化を図れる冷凍機用熱交
換器を提供することを目的としている。Therefore, despite the simple structure of the present invention, the heat transfer area and heat transfer coefficient on the low-pressure side are drastically increased while suppressing the pressure loss, thereby achieving a high-efficiency and compact heat exchanger for a refrigerator. The purpose is to provide a vessel.
［発明の構成］ （問題点を解決するための手段） 上記目的を達成するために、本発明は、低圧の冷媒ガ
スが流れる配管内に高圧の冷媒ガスが流れる配管を配置
し、高圧の冷媒ガスが流れる配管の管壁を介して両冷媒
ガスを熱交換させるようにした冷凍機用熱交換器におい
て、前記低圧の冷媒ガスが流れる配管内に互いが部分的
に接合状態で、かつ前記高圧の冷媒ガスが流れる配管と
も接合状態にある良熱伝導材製球体の集合層を前記低圧
の冷媒ガスの流れ方向に断熱層を介在させて複数設けて
いる。[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, the present invention provides a high-pressure refrigerant by arranging a pipe through which a high-pressure refrigerant gas flows within a pipe through which a low-pressure refrigerant gas flows. In a heat exchanger for a refrigerator in which both refrigerant gases are heat-exchanged through a pipe wall of a pipe through which gas flows, the refrigerant is partially joined to each other in a pipe through which the low-pressure refrigerant gas flows, and A plurality of aggregated layers of spheres made of a good heat conductive material that are also joined to a pipe through which the refrigerant gas flows are provided with a heat insulating layer interposed in the flow direction of the low-pressure refrigerant gas.
（作用） 低圧の冷媒ガスは、集合層を構成している球体と球体
との増を流れる。このとき、流速の増加によって低圧の
冷媒ガスと球体との熱伝達は非常に高く、また伝熱面積
も全ての球体の表面積の和となり非常に大きいものとな
る。また、球体を用いているので、圧力損失は低く抑え
られる。さらに、低圧の冷媒ガスの流れ方向に断熱層を
介在させて集合層を複数分離配置しているので、集合層
を通して熱伝導で熱交換器の両端間に熱が伝わるのを抑
制できる。したがって、集合層を設けたことによって熱
伝導損失が増加するのを抑制できる。(Operation) The low-pressure refrigerant gas flows through the spheres constituting the aggregated layer. At this time, the heat transfer between the low-pressure refrigerant gas and the spheres is extremely high due to the increase in the flow velocity, and the heat transfer area is also the sum of the surface areas of all the spheres, which is very large. Further, since a sphere is used, the pressure loss can be kept low. Furthermore, since a plurality of aggregated layers are arranged separately with the heat insulating layer interposed in the flow direction of the low-pressure refrigerant gas, it is possible to suppress the transfer of heat between the two ends of the heat exchanger by heat conduction through the aggregated layers. Therefore, an increase in heat conduction loss due to the provision of the aggregate layer can be suppressed.
（実施例） 以下、図面を参照しながら実施例を説明する。(Example) Hereinafter, an example is described, referring to drawings.
第１図は本発明の一実施例に係るヘリウム冷凍機用の
熱交換器を示す断面図で、第３図と同一部分は同符号で
示してある。従って、重複する部分の詳しい説明は省略
する。FIG. 1 is a sectional view showing a heat exchanger for a helium refrigerator according to one embodiment of the present invention, and the same parts as those in FIG. 3 are denoted by the same reference numerals. Therefore, a detailed description of the overlapping part will be omitted.
この実施例が従来のものと異なる点は、低圧側流路に
ある。すなわち、低圧側流路内には0.2から10mm程度の
銅製の球体７を集合させた集合層８が流れ方向に数ケ所
50〜200メッシュ程度のステンレス金網を複数枚を重ね
た断熱層９を介して装着されている。球体７は低圧側配
管入口５から低圧側配管出口６に向かうにしたがって直
径の大きなものが使われている。また、球体７と銅製の
高圧側配管２および球体７どうしは拡散接合によって互
いに部分的に接合されている。This embodiment differs from the conventional one in the flow path on the low pressure side. That is, in the low-pressure side flow path, an aggregate layer 8 in which copper spheres 7 of about 0.2 to 10 mm are gathered at several places in the flow direction.
A stainless steel mesh of about 50 to 200 mesh is mounted via a heat insulating layer 9 in which a plurality of layers are stacked. The sphere 7 has a larger diameter from the low-pressure side pipe inlet 5 to the low-pressure side pipe outlet 6. The sphere 7, the copper high-pressure side pipe 2 and the sphere 7 are partially joined to each other by diffusion bonding.
このような構成であると、低圧のガスヘリウムは集合
層８を構成している球体７の間を通って流れ、球体７と
熱交換を行う。このとき、ガスヘリウムの流速が増すの
でガスヘリウムと集合層８との間には高い熱伝達が得ら
れ、伝熱面積も球体７の表面積の総和となり非常に大き
くなる。また、球体７間には約40％もの通流スペースが
あるため圧力損失も低い値に抑えられる。高圧のガスヘ
リウムの熱は高圧側配管２の管壁で熱交換し、球体７へ
と伝わる。高圧側配管２と球体７とは接合しているため
熱抗抵も小さい。このため効率よく低圧のガスヘリウム
へ熱が伝わる。極低温熱交換器の場合、両端の温度差が
大きくなる場合が多く、流れ方向の熱伝導によって引起
こされる損失も無視できない。しかしながら、流れ方向
に断熱層９が設けられているため、十分熱伝導損失を減
少させることができる。このため、従来の熱交換器に比
べ、小型で高性能な熱交換器を実現できる。With such a configuration, the low-pressure gas helium flows between the spheres 7 constituting the collecting layer 8 and exchanges heat with the spheres 7. At this time, since the flow rate of gas helium increases, high heat transfer is obtained between gas helium and the aggregate layer 8, and the heat transfer area becomes the sum of the surface areas of the spheres 7 and becomes extremely large. Further, since there is a flow space of about 40% between the spheres 7, the pressure loss can be suppressed to a low value. The heat of the high-pressure gas helium exchanges heat on the wall of the high-pressure side pipe 2 and is transmitted to the sphere 7. Since the high pressure side pipe 2 and the sphere 7 are joined, the thermal resistance is also small. For this reason, heat is efficiently transmitted to low-pressure gas helium. In the case of a cryogenic heat exchanger, the temperature difference between both ends is often large, and the loss caused by heat conduction in the flow direction cannot be ignored. However, since the heat insulating layer 9 is provided in the flow direction, the heat conduction loss can be sufficiently reduced. For this reason, a small-sized and high-performance heat exchanger can be realized as compared with the conventional heat exchanger.
なお、本発明は上述した実施例に限定されるものでは
ない。例えば、球体は銅製に限られるものではなく、ア
ルミニウム等の良熱伝導性のものを使用してもよい。ま
た、断熱層も金網に限らず、メタルウール、グラスウー
ルを使用してもよい。また、その使用例もヘリウム冷凍
機用に限定されるものではない。The present invention is not limited to the embodiments described above. For example, the spheres are not limited to those made of copper, but may be made of a material having good heat conductivity such as aluminum. Further, the heat insulating layer is not limited to the wire mesh, and metal wool or glass wool may be used. Further, the usage example is not limited to the helium refrigerator.
［発明の効果］ 以上述べたように本発明によれば、低圧側の圧力損失
を抑えたまま、伝熱面積と熱伝達率を増大させることが
できるため、小型で高効率の冷凍機用熱交換器を提供で
きる。[Effects of the Invention] As described above, according to the present invention, it is possible to increase the heat transfer area and the heat transfer coefficient while suppressing the pressure loss on the low pressure side. Exchanger can be provided.
第１図は本発明の一実施例に係る熱交換器の縦断面図、
第２図は温度効率とNTUの関係を表す図、第３図は従来
の熱交換器の模式図である。 １……熱交換器外筒、２……高圧側配管、３……高圧側
配管入口、４……高圧側配管出口、５……低圧側配管入
口、６……低圧側配管出口、７……球体、８……集合
層、９……断熱層。FIG. 1 is a longitudinal sectional view of a heat exchanger according to one embodiment of the present invention,
FIG. 2 is a diagram showing the relationship between temperature efficiency and NTU, and FIG. 3 is a schematic diagram of a conventional heat exchanger. 1 ... heat exchanger outer cylinder, 2 ... high pressure side piping, 3 ... high pressure side piping inlet, 4 ... high pressure side piping outlet, 5 ... low pressure side piping inlet, 6 ... low pressure side piping outlet, 7 ... ... sphere, 8 ... assembly layer, 9 ... insulation layer.
Claims (3)
媒ガスが流れる配管を配置し、高圧の冷媒ガスが流れる
配管の管壁を介して両冷媒ガスを熱交換させるようにし
た冷凍機用熱交換器において、前記低圧の冷媒ガスが流
れる配管内に互いが部分的に接合状態で、かつ前記高圧
の冷媒ガスが流れる配管とも接合状態にある良熱伝導材
製球体の集合層を前記低圧の冷媒ガスの流れ方向に断熱
層を介在させて複数設けてなることを特徴とする冷凍機
用熱交換器。1. A refrigerator in which a pipe through which a high-pressure refrigerant gas flows is disposed in a pipe through which a low-pressure refrigerant gas flows, and heat exchange is performed between the two refrigerant gases through a pipe wall of the pipe through which the high-pressure refrigerant gas flows. In the heat exchanger, the aggregate layer of the sphere made of a good heat conductive material, which is partially joined to each other in a pipe through which the low-pressure refrigerant gas flows, and also joined to a pipe through which the high-pressure refrigerant gas flows, A heat exchanger for a refrigerator comprising a plurality of heat insulating layers interposed in the flow direction of a low-pressure refrigerant gas.
とを特徴とする特許請求の範囲第１項記載の冷凍機用熱
交換器。2. The heat exchanger for a refrigerator according to claim 1, wherein said sphere has a diameter of 0.2 mm to 10 mm.
球体の大きさが前記低圧の冷媒ガスの流れ方向に異なっ
ていることを特徴とする特許請求の範囲第１項記載の冷
凍機用熱交換器。3. The refrigeration system according to claim 1, wherein the size of the spheres constituting each of the collective layers differs in the flow direction of the low-pressure refrigerant gas. Heat exchanger.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62241354A JP2633581B2 (en) | 1987-09-26 | 1987-09-26 | Heat exchanger for refrigerator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP62241354A JP2633581B2 (en) | 1987-09-26 | 1987-09-26 | Heat exchanger for refrigerator |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6484094A JPS6484094A (en) | 1989-03-29 |
| JP2633581B2 true JP2633581B2 (en) | 1997-07-23 |
Family
ID=17073050
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP62241354A Expired - Lifetime JP2633581B2 (en) | 1987-09-26 | 1987-09-26 | Heat exchanger for refrigerator |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2633581B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007176729A (en) * | 2005-12-27 | 2007-07-12 | Sumitomo Heavy Ind Ltd | Ozone gas transfer device |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5187849A (en) * | 1975-01-31 | 1976-07-31 | Inoue Japax Res | NETSUKOKANKISEIZOHOHO |
| FR2436953A1 (en) * | 1978-09-21 | 1980-04-18 | Saint Gobain | THERMAL EXCHANGE DEVICE BETWEEN SOLID PARTICLES AND A GAS STREAM |
-
1987
- 1987-09-26 JP JP62241354A patent/JP2633581B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6484094A (en) | 1989-03-29 |
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