JP4360020B2 - Regenerative refrigerator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a regenerative refrigerator.
[0002]
[Prior art]
As a regenerative refrigerator that generates cold by reciprocating a working gas in a regenerator and transporting heat, a pulse tube refrigerator, a GM refrigerator, a Stirling refrigerator, and the like are known. Such a regenerator type refrigerator typically uses a regenerator having a low temperature end and a high temperature end, and pumps heat from the low temperature end side to the high temperature end side when the working gas reciprocates the regenerator, Cold is generated at the cold end of the regenerator. Accordingly, the cold generated at the low temperature end portion of the regenerator is thermally coupled to the cooled object to cool the cooled object.
[0003]
In a normal regenerative refrigerator, if the required coldness is relatively high and one, a single-stage regenerative refrigerator is sufficient, but the required coldness is around the liquid helium temperature range. When there are two or more cooling locations, a two-stage regenerative refrigerator is used. For example, a regenerative refrigerator that is used for a single cooling target that needs to be cooled in a liquid nitrogen temperature range (about 77K) is usually a single-stage refrigerating refrigerator that is obtained at the low temperature end of the regenerator. What is necessary is just to couple | bond the cold of about 77K to the said cooling target object thermally. On the other hand, when a regenerative refrigerator is used for a cooling target that needs to be cooled in the liquid helium temperature range (about 4.2 K), the liquid nitrogen tank or the first first so as to surround the outer periphery of the cooling target. A means for reducing the radiant heat to the cooling target is provided by providing a radiant heat shield plate. Therefore, in order to use the regenerative refrigerator in such a liquid helium temperature range, it is necessary to cool the object to be cooled by about 4K and cool the liquid nitrogen tank or the first radiant heat shield plate by about 77K. is there. In this case, usually a two-stage regenerative refrigerator is used, and the cold of about 77K obtained at the low-temperature end of the first-stage regenerator is thermally coupled to the liquid nitrogen tank or the first radiant heat shield plate, The cold of about 4K obtained at the cold storage cold end is thermally coupled to the object to be cooled.
[0004]
[Problems to be solved by the invention]
As described above, conventionally, when there are a plurality of places where refrigeration at different temperature levels is necessary, a multi-stage type regenerative refrigerator having a number of regenerators corresponding to the temperature is stacked. However, as the number of multi-stages increases, the configuration becomes more complicated, time is required for design, the entire apparatus becomes larger, and the space becomes disadvantageous. Furthermore, the increase in the number of stages naturally increases the cost, which is not preferable economically.
[0005]
For example, when a regenerative refrigerator is used for a cooling target that needs to be cooled in the liquid helium temperature range as shown in the above prior art, usually a two-stage regenerative refrigerator is used as described above. The low-temperature end of the second stage regenerator is thermally coupled to the object to be cooled, and the low-temperature end of the second regenerator is thermally coupled to the liquid nitrogen tank or the first radiant heat shield plate. When heat intrusion into the object is significant, a second radiant heat shield plate with a temperature of about 20K is provided between the object to be cooled and the liquid nitrogen tank or the first radiant heat shield plate to completely shut out the radiant heat from the outside. There is a need to. In this case, usually a three-stage regenerative refrigerator is used, and the cold of about 77 K obtained at the low-temperature end of the first-stage regenerator is thermally coupled to the liquid nitrogen tank or the first radiant heat shield plate. The cold of about 20K obtained at the low temperature end of the regenerator at the stage is thermally coupled to the second radiant heat shield plate, and the cold of about 4K obtained at the low end of the regenerator at the third stage is used as the object to be cooled. Thermally bond.
[0006]
However, the three-stage regenerative refrigerator is much more complicated in configuration than the two-stage regenerative refrigerator, and the lead time required for the design is increased. In addition, the three-stage regenerative refrigerator is inevitably large in overall configuration due to the complexity of its configuration, which is disadvantageous in terms of space. Further, the three-stage regenerative refrigerator is disadvantageous in terms of cost as compared with the two-stage regenerative refrigerator.
[0007]
This invention is made | formed in view of the said situation, and makes it a technical subject to eliminate the said malfunction accompanying multi-stage in a cool storage type refrigerator.
[0008]
[Means for Solving the Problems]
  The present invention made to solve the above technical problem uses a regenerator having a low temperature end and a high temperature end, and heat is transferred from the low temperature end side to the high temperature end side when the working gas reciprocates the regenerator. In the regenerative refrigerator that generates cold by pumping, the regenerator is thermally coupled to a first stage regenerator having a low temperature end and a high temperature end, and a low temperature end and a low temperature end of the first stage regenerator A second-stage regenerator having a high-temperature end, an intermediate heat exchanger interposed between the low-temperature end and the high-temperature end of the second-stage regenerator, and using helium gas as the working gas The regenerative refrigerator is operated so that the temperature at the low temperature end of the second stage regenerator is 2 to 10 K, and the heat loss due to the non-ideality of the helium gas is absorbed from the intermediate heat exchanger. And the intermediate heat exchanger is included in the second stage regenerator. An inner intermediate heat exchanger, and an outer intermediate heat exchanger disposed outside the second-stage regenerator, the inner intermediate heat exchanger and the outer intermediate heat exchanger. And a displacer incorporating the second-stage regenerator and the intermediate heat exchanger, and a second-stage cylinder in which the displacer reciprocates, respectively.WithA gap is formed between a side surface of the displacer and a side inner wall of the second-stage cylinder, and the working gas in the space on the high-temperature end side of the second-stage cold storage material enters the gap, and the gap To the space on the low-temperature end side of the second-stage regenerator material.
[0009]
  According to the present invention, in the regenerator used in the regenerator type refrigerator, when the non-ideality of the working gas at the low temperature end appears remarkably, an intermediate between the low temperature end and the high temperature end of the regenerator is present. A heat exchanger is interposed, and the heat loss due to the non-ideality of the working gas is absorbed from the heat exchanger.
  Therefore, in addition to the low temperature end of the regenerator, heat is also absorbed from the intermediate heat exchanger interposed between the low temperature end and the high temperature end, and the cold generated in this part can be efficiently provided to the object to be cooled. Therefore, it is possible to provide two or more cold take-out portions with one regenerator, and it is possible to cool an object to be cooled having a plurality of refrigerating points without using multiple stages of regenerative refrigerators. For this reason, the said malfunction accompanying multi-stage can be eliminated.
  When the gas can be approximated as an ideal gas, 1−T (∂V / ∂T) P / V = 0 holds from the ideal gas equation of state. On the other hand, when | 1-T (∂V / ∂T) P / V |> 0.01, gas non-ideality appears. This is a state where the virial coefficient is so large that it cannot be ignored when the state equation of the real gas is approximated by, for example, the virial equation. In such a state, that is, when the gas non-ideality appears to be approximately 1% or more, the effect when the present invention is applied is great.
  In addition, the cold storage refrigerator is a two-stage cold storage refrigerator, and an intermediate heat exchanger is interposed between the low temperature end and the high temperature end of the second stage cold storage device. When a two-stage regenerative refrigerator is used, extremely low coldness can be obtained at the low temperature end of the second-stage regenerator. For example, if helium is used as the working gas, it is possible to obtain a chill of about 4K at the low temperature end of the second stage regenerator. In this temperature range, the working gas is significantly non-ideal. Accordingly, an intermediate heat exchanger is interposed between the low-temperature end and the high-temperature end of the second-stage regenerator where the non-ideality of the working gas appears remarkably, and heat is absorbed from the intermediate heat exchanger, so that the two-stage type In the regenerator, there are three cold take-out parts, that is, a cold take-out part at the low temperature end of the first stage regenerator, a cold take out part at the intermediate heat exchanger, and a cold take out at the low temperature end of the second stage regenerator. The part can be obtained efficiently. For this reason, the to-be-cooled body which has three freezing locations can be cooled, without making a cool storage type refrigerator into 3 steps | paragraphs, and the malfunction accompanying 3 steps | paragraphs can be eliminated.
  In addition, if helium gas is used as the working gas and the regenerator is operated so that the temperature at the low temperature end of the second stage regenerator is about 2 to 10 K, the working gas is notable in the second stage regenerator. Showing non-ideality. Therefore, in such a case, if an intermediate heat exchanger is interposed between the low-temperature end and the high-temperature end of the second-stage regenerator, the temperature (for example, 60K) and the low-temperature end of the second-stage regenerator The cold can be efficiently taken out at a temperature in the region between the first temperature (for example, 4K), for example, in a temperature region of about 10-20K.
  Also, the intermediate heat exchanger is divided into an inner intermediate heat exchanger and an outer intermediate heat exchanger, the inner intermediate heat exchanger is disposed inside the second stage regenerator, and the outer intermediate heat exchanger is arranged as the second stage regenerator. It is arranged on the outer periphery of the vessel. Therefore, the cold generated in the second stage regenerator is first transferred to the inner intermediate heat exchanger, and then transferred to the outer intermediate heat exchanger. And a to-be-cooled body is made to contact | abut to this outer side intermediate heat exchanger, and a to-be-cooled body is cooled. In this way, it is possible to easily take out the cold from the middle part of the regenerator.
  Further, the working gas in the space on the high temperature end side of the second-stage regenerator material enters the gap and is introduced from the gap into the space on the low-temperature end side of the second-stage regenerator material. Since the gap is located at the facing portion between the outer intermediate heat exchanger and the inner intermediate heat exchanger, the working gas enters and exits the gap during the operation of the refrigerator, so forced convection occurs in this portion. For this reason, convective heat transfer is promoted, the heat transfer coefficient between the inner intermediate heat exchanger and the outer intermediate heat exchanger is increased, and the refrigeration output (heat absorption amount) in the outer intermediate heat exchanger can be improved. it can.
[0010]
  The present invention also provides:In a regenerative refrigerator that uses a regenerator having a low temperature end and a high temperature end, and generates cold by pumping heat from the low temperature end side to the high temperature end side when the working gas reciprocates through the regenerator, The regenerator has a first stage regenerator having a low temperature end and a high temperature end, and a second stage regenerator having a low temperature end and a high temperature end thermally coupled to the low temperature end of the first stage regenerator, An intermediate heat exchanger is interposed between the low temperature end and the high temperature end of the second stage regenerator, helium gas is used as the working gas, and the temperature at the low temperature end of the second stage regenerator is 2 to 2 The regenerative refrigerator is operated so as to be 10K, the heat loss due to the non-ideality of the helium gas is absorbed from the intermediate heat exchanger, and the intermediate heat exchanger is the second stage regenerator An inner intermediate heat exchanger disposed inside, and the second stage cold storage An outer intermediate heat exchanger disposed on the outer periphery of the outer intermediate heat exchanger, wherein the inner intermediate heat exchanger and the outer intermediate heat exchanger are respectively disposed in a substantially facing positional relationship, and the second stage cold storage A displacer for reciprocating the working gas between the heat exchanger and the intermediate heat exchanger, wherein the second-stage regenerator and the intermediate heat exchanger are provided on an outer periphery of the displacer, and the high-temperature end side of the second-stage regenerator material The working gas in the space is introduced into the space on the low temperature end side of the second-stage cold storage material through the inner intermediate heat exchanger.
[0011]
  According to the present invention, in the regenerator used in the regenerator type refrigerator, when the non-ideality of the working gas at the low temperature end appears remarkably, an intermediate between the low temperature end and the high temperature end of the regenerator is present. A heat exchanger is interposed, and the heat loss due to the non-ideality of the working gas is absorbed from the heat exchanger.
  Therefore, in addition to the low temperature end of the regenerator, heat is also absorbed from the intermediate heat exchanger interposed between the low temperature end and the high temperature end, and the cold generated in this part can be efficiently provided to the object to be cooled. Therefore, it is possible to provide two or more cold take-out portions with one regenerator, and it is possible to cool an object to be cooled having a plurality of refrigerating points without using multiple stages of regenerative refrigerators. For this reason, the said malfunction accompanying multi-stage can be eliminated.
  When the gas can be approximated as an ideal gas, 1−T (∂V / ∂T) P / V = 0 holds from the ideal gas equation of state. On the other hand, when | 1-T (∂V / ∂T) P / V |> 0.01, gas non-ideality appears. This is a state where the virial coefficient is so large that it cannot be ignored when the state equation of the real gas is approximated by, for example, the virial equation. In such a state, that is, when the gas non-ideality appears to be approximately 1% or more, the effect when the present invention is applied is great.
  In addition, the cold storage refrigerator is a two-stage cold storage refrigerator, and an intermediate heat exchanger is interposed between the low temperature end and the high temperature end of the second stage cold storage device. When a two-stage regenerative refrigerator is used, extremely low coldness can be obtained at the low temperature end of the second-stage regenerator. For example, if helium is used as the working gas, it is possible to obtain a chill of about 4K at the low temperature end of the second stage regenerator. In this temperature range, the working gas is significantly non-ideal. Accordingly, an intermediate heat exchanger is interposed between the low-temperature end and the high-temperature end of the second-stage regenerator where the non-ideality of the working gas appears remarkably, and heat is absorbed from the intermediate heat exchanger, so that the two-stage type In the regenerator, there are three cold take-out parts, that is, a cold take-out part at the low temperature end of the first stage regenerator, a cold take out part at the intermediate heat exchanger, and a cold take out at the low temperature end of the second stage regenerator. The part can be obtained efficiently. For this reason, the to-be-cooled body which has three freezing locations can be cooled, without making a cool storage type refrigerator into 3 steps | paragraphs, and the malfunction accompanying 3 steps | paragraphs can be eliminated.
  In addition, if helium gas is used as the working gas and the regenerator is operated so that the temperature at the low temperature end of the second stage regenerator is about 2 to 10 K, the working gas is notable in the second stage regenerator. Showing non-ideality. Therefore, in such a case, if an intermediate heat exchanger is interposed between the low-temperature end and the high-temperature end of the second-stage regenerator, the temperature (for example, 60K) and the low-temperature end of the second-stage regenerator The cold can be efficiently taken out at a temperature in the region between the first temperature (for example, 4K), for example, in a temperature region of about 10-20K.
  Also, the intermediate heat exchanger is divided into an inner intermediate heat exchanger and an outer intermediate heat exchanger, the inner intermediate heat exchanger is disposed inside the second stage regenerator, and the outer intermediate heat exchanger is arranged as the second stage regenerator. It is arranged on the outer periphery of the vessel. Therefore, the cold generated in the second stage regenerator is first transferred to the inner intermediate heat exchanger, and then transferred to the outer intermediate heat exchanger. And a to-be-cooled body is made to contact | abut to this outer side intermediate heat exchanger, and a to-be-cooled body is cooled. In this way, it is possible to easily take out the cold from the middle part of the regenerator.
  In addition, since the gap between the inner intermediate heat exchanger and the outer intermediate heat exchanger can be eliminated, heat transfer between the outer intermediate heat exchanger and the inner intermediate heat exchanger is improved, and the outer intermediate heat exchanger The amount of heat absorbed by the vessel can be increased.
[0020]
  Also,BookThe invention
  in frontThe cooling object of the regenerative refrigerator is a main cooling object that needs to be cooled in the liquid helium temperature range, a second radiant heat shield plate disposed around the main cooling object, and the second radiant heat. A cooling system comprising a liquid nitrogen tank or a first radiant heat shield plate disposed around the shield plate, and the cold generated at the low temperature end of the second stage regenerator is used for cooling the main cooling object. The cold generated at the low temperature end of the first stage regenerator is used for cooling the liquid nitrogen tank or the first radiant heat shield plate, and the cold generated in the intermediate heat exchanger is used for the second radiant heat shield plate. It is characterized by being used for cooling.
[0021]
  BookAccording to the invention, the object to be cooled includes a main cooling object that needs to be cooled in the liquid helium temperature range, a second radiant heat shield plate disposed around the main cooling object, and a second radiant heat shield plate. In the case of a cooling system including a liquid nitrogen tank or a first radiant heat shield plate arranged around the liquid nitrogen tank, the main cooling object is cooled by the cold generated at the low temperature end of the second-stage regenerator. Alternatively, the second radiant heat shield plate is cooled by cold generated at the low temperature end of the first stage regenerator, and the second radiant heat shield plate is cooled by cold generated by the intermediate heat exchanger. For this reason, it becomes possible to cool the cooling system having the three cooling points with a two-stage regenerative refrigerator using the present invention, and a device having this type of cooling system, for example, a superconducting magnet device for MRI. Can be efficiently cooled.
[0022]
The main cooling object is not limited in its purpose and mode as long as it is an object that requires cooling in the liquid helium temperature range. Parts that originally function in the liquid helium temperature range, such as electronic elements, have been used by being immersed in liquid helium in the past. Therefore, in such a case, the main cooling object is liquid helium or a liquid helium tank, and its purpose is to prevent evaporation of liquid helium. However, due to recent advances in refrigeration technology, it has become possible to obtain a predetermined output in the liquid helium temperature range even in the cold generation part of the refrigerator, so the above electronic elements etc. are directly coupled to the refrigerator. (I.e. without using liquid helium). Therefore, in such a case, the main cooling object is the electronic element or the like, and the purpose is cooling the electronic element or the like. As described above, the “main cooling object” in the present specification is appropriately determined depending on the configuration of the cooling system to be applied, regardless of the purpose or mode.
[0023]
  Also,BookThe invention
  in frontThe regenerative refrigerator is a pulse tube refrigerator. By applying the present invention as a pulse tube refrigerator, it is possible to reduce the vibration applied to the object to be cooled, realize maintenance-free operation at a low temperature part, and facilitate the operation of the refrigerator in a magnetic field.
[0024]
  Also,BookThe invention
  in frontThe regenerative refrigerator is a GM refrigerator or a Stirling refrigerator. By applying the present invention as a GM refrigerator or a Stirling refrigerator, high efficiency and high reliability can be ensured.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
First, the principle of the present invention will be described.
[0026]
If the working gas used in the regenerator can be approximated as an ideal gas and the regenerator regenerative action is complete, the enthalpy flow from the high temperature end of the regenerator to the low temperature end can be regarded as almost zero, and the low temperature end of the regenerator Thus, almost the same amount of heat (endothermic amount) as the PV illustrated work performed by the working gas is absorbed at the low temperature end. For example, consider the regenerator 10 shown in FIG. In FIG. 1, the regenerator 10 includes a low temperature end 10L and a high temperature end 10H, and a low temperature end heat exchanger 11L and a high temperature end heat exchanger 11H are attached to the respective ends. Further, assuming that the working gas is helium gas, the working gas has a variable pressure range of 0.7 MPa to 2.0 MPa, the temperature at the regenerator low temperature end 10L is 60K, and the temperature at the regenerator high temperature end 10H is 300K, the regenerator 10 The ideality of the working gas is maintained over the entire region from the low temperature end 10L to the high temperature end 10H. In other words, the working gas can be regarded as an ideal gas approximately, 1-T (∂V / ∂T)_P/ V = 0 holds. In this case, assuming that the regenerative operation of the regenerator is complete, no enthalpy flow from the high temperature end 10H to the low temperature end 10L of the regenerator 10 occurs, and the amount of heat equal to the PV illustrated work of the working gas at the low temperature end 10L. Is absorbed from the low temperature end heat exchanger 11L attached to the low temperature end 10L. For example, when the PV illustrated work of the working gas at the low temperature end 10L is 40 W, the endothermic amount at the low temperature end heat exchanger 11L is also 40 W.
[0027]
Next, consider the regenerator 20 shown in FIG. In FIG. 2, the basic configuration of the regenerator 20, the type of working gas, and the fluctuating pressure are the same as those of the regenerator 10 of FIG. 1. That is, the regenerator 20 includes a low temperature end 20L and a high temperature end 20H, and a low temperature end heat exchanger 21L and a high temperature end heat exchanger 21H are attached to the respective ends. The working gas is helium, and the working pressure range of the working gas is 0.7 MPa to 2.0 MPa. However, the temperature at the regenerator cold end 20L is 4.2K, and the temperature at the regenerator high temperature end 20H is 60K, which is different from the regenerator 10 of FIG. In this case, the non-ideality of the working gas is prominent in the vicinity of the cold storage cold end 20L, and | 1-T (∂V / ∂T)_P/V|>0.01. In such a state, even when the regenerative action of the regenerator 20 is complete, an enthalpy flow from the high temperature end 20H to the low temperature end 20L of the regenerator 20 is generated, and the PV illustrated in FIG. The amount of heat corresponding to the work is not absorbed from the low temperature end heat exchanger 21L. For example, when the PV illustrated work of the working gas at the low temperature end 20L is 10 W, the endothermic amount at the low temperature end 20L is about 2 W. As described above, when the PV illustrated work of the working gas does not coincide with the endothermic amount, and there is a difference, the difference must be compensated for somewhere on the energy balance, but the side surface 20a of the regenerator 20 is adiabatic. When the regenerator 20 is formed of a material or when the regenerator 20 is disposed in an adiabatic environment, the difference (8 W) is the high temperature end heat exchanger 21H attached to the high temperature end 20H of the regenerator 20. Must absorb heat.
[0028]
In contrast, a regenerator 30 according to the present invention is shown in FIG. The regenerator 30 includes a low temperature end 30L and a high temperature end 30H, and a low temperature end heat exchanger 31L and a high temperature end heat exchanger 31H are attached to the respective ends. And the intermediate heat exchanger 50 is interposing between the cool storage low temperature end 30L and the cool storage high temperature end 30H. The type of the working gas, the fluctuating pressure, and the temperature at the end are the same as in the case of the regenerator 20 of FIG. That is, the working gas is helium gas, the fluctuating pressure is 0.7 MPa to 2.0 MPa, the temperature at the regenerator low temperature end 30L is 4.2K, and the temperature at the regenerator high temperature end 30H is 60K. In this case, similarly to the regenerator 20 of FIG. 2, the non-ideality of the working gas appears remarkably in the vicinity of the regenerator low temperature end 30L, and | 1-T (∂V / ∂T)_P/V|>0.01. In such a state, even if the regenerative operation of the regenerator 30 is complete, an enthalpy flow from the high temperature end 30H to the low temperature end 30L of the regenerator 30 is generated, and the PV illustrated in FIG. The same amount of heat for work cannot be absorbed from the low temperature end heat exchanger 31L. For example, when the PV illustrated work of the working gas at the low temperature end 30L is 10 W, the endothermic amount at the low temperature end 30L is about 2 W. However, unlike the case of FIG. 2, in the regenerator 30 of FIG. 3, the intermediate heat exchanger 50 is interposed between the low temperature end 30L and the high temperature end 30H. Therefore, a part of the difference (8 W) between the PV illustrated work of the working gas at the low temperature end 30L and the heat absorption amount at the low temperature end heat exchanger 31L is also absorbed by the intermediate heat exchanger 50. How much heat absorption is possible depends on the non-ideal nature of the working gas at that temperature and pressure. Since the intermediate heat exchanger 50 is interposed between the low temperature end and the high temperature end as described above, the temperature is also the temperature at the low temperature end (4.2K) and the temperature at the high temperature end (60K). Between the temperatures. For example, if the temperature of this part is set to a temperature of 10 to 20 K, and the working gas can be regarded as an ideal gas in this temperature range and pressure, a low temperature of 10 to 20 K at the output of 8 W at the part of this heat exchanger. It can be taken out. When the working gas is non-ideal in this temperature range and pressure, it is affected by the non-ideality, so that a low temperature of 10 to 20 K can be taken out with an output of 6 W, for example, in the heat exchanger. .
[0029]
Comparing the regenerator 20 shown in FIG. 2 with the regenerator 30 shown in FIG. 3, the regenerator 20 shown in FIG. 2 has an enthalpy component that cannot absorb heat at the low temperature end 20L due to non-ideality of the working gas. However, the regenerator 30 shown in FIG. 3 has an enthalpy component that cannot absorb heat at the low temperature end 30L due to non-ideality of the working gas. The heat absorption from the intermediate heat exchanger 50 interposed between the high temperature end 30H and the low temperature end 30L can be supplemented. Can be used as
[0030]
On the other hand, consider the regenerator 40 shown in FIG. The regenerator 40 has an intermediate heat exchanger 51 interposed between the low temperature end 40L and the high temperature end 40H in addition to the configuration of the regenerator 10 shown in FIG. Also, the type of working gas, the fluctuating pressure, the temperature at the low temperature end and the high temperature end are the same as in FIG. That is, the type of working gas is helium gas, the fluctuating pressure is 0.7 MPa to 1.0 MPa, the temperature at the low temperature end is 60K, and the temperature at the high temperature end is 300K. In this case, as in the regenerator 10 of FIG. 1, the ideality of the working gas is maintained over the entire region from the low temperature end 40L to the high temperature end 40H, and the working gas can be regarded as an ideal gas approximately. V / ∂T)_P/ V = 0 holds. In this case, assuming that the regenerative action of the regenerator 40 is complete, an enthalpy flow from the high temperature end 40H to the low temperature end 40L does not occur, and the amount of heat equivalent to the PV illustrated work of the working gas at the low temperature end 40L is low. Heat should be absorbed from the low temperature end heat exchanger 41L attached to the end 40L. For example, when the PV illustrated work of the working gas at the low temperature end 40L is 40W, the heat absorption amount at the low temperature end heat exchanger 41L should be 40W. However, in the case of FIG. 4, since the intermediate heat exchanger 51 is interposed between the low temperature end 40 </ b> L and the high temperature end 40 </ b> H of the regenerator 40, heat absorption also occurs from this intermediate heat exchanger 51 portion. For example, if the temperature of the intermediate heat exchanger 61 is 100K, an endothermic heat of 10 W occurs in this portion. For this reason, the endothermic amount at the intermediate heat exchanger 51 is subtracted from the endothermic amount at the low temperature end 40L, and the endothermic amount at the low temperature end 40L becomes 30W. Therefore, even if a heat exchanger is interposed between the low temperature end and the high temperature end of the regenerator as long as the ideality of the working gas is maintained, the heat absorption at the low temperature end is reduced.
[0031]
When comparing the regenerator 40 shown in FIG. 4 and the regenerator 30 shown in FIG. 3, the ideality of the working gas at the low temperature end is maintained in the case of FIG. 4, and the non-ideality is noticeable in the case of FIG. It differs in the point that it appears. In this case, in the regenerator 40 of FIG. 4, the heat absorption amount obtained by the intermediate heat exchanger 61 is obtained by separating a part of the heat absorption amount that should originally be obtained by the low temperature end heat exchanger 41L into the intermediate heat exchanger 51. In contrast, in the regenerator 30 of FIG. 3, heat absorption is obtained by the intermediate heat exchanger 50 regardless of the amount of heat absorption obtained by the low-temperature end heat exchanger 31L. That is, even when the intermediate heat exchanger 50 is removed from the regenerator 30 of FIG. 3 or attached as shown in FIG. 3, the amount of heat absorbed by the low temperature end heat exchanger 31L does not change. For this reason, in the regenerator 30 of FIG. 3, it is possible to efficiently obtain heat absorption by the intermediate heat exchanger 50 without affecting the amount of heat absorption obtained by the low temperature end heat exchanger 30L.
[0032]
FIG. 5 shows a two-stage pulse tube refrigerator when the present invention is applied to a second-stage regenerator. In the figure, the two-stage pulse tube refrigerator 60 includes a first-stage regenerator 71, a second-stage regenerator 72, a first-stage pulse tube 81, and a second-stage pulse tube 82. The first stage regenerator 71 includes a high temperature end 71H and a low temperature end 71L, and the second stage regenerator 72 includes a high temperature end 72H and a low temperature end 72L. The first stage pulse tube 81 includes a high temperature end 81H and a low temperature end 81L, and the second stage pulse tube 82 includes a high temperature end 82H and a low temperature end 82L. A high temperature end heat exchanger 71 a is attached to the high temperature end 71 </ b> H of the first stage regenerator 71. The low temperature end 81L of the first stage pulse tube 81 and the low temperature end 71L of the first stage regenerator 71 are in thermal communication, and the low temperature end 82L of the second stage pulse tube 82 and the low temperature end of the second stage regenerator 72 are connected. 72L is in thermal communication. A first stage heat exchanger 91 is attached to the low temperature end 81L of the first stage pulse tube 81, and a second stage heat exchanger 92 is attached to the low temperature end 82L of the second stage pulse tube 82, respectively. Further, an intermediate heat exchanger 93 is interposed between the high temperature end 72H and the low temperature end 72L of the second stage regenerator 72. A pressure vibration generator 94 is provided on the high temperature end 71H side of the first stage regenerator 71, and a first stage phase adjusting mechanism 95 is provided on the high temperature end 81H side of the first stage pulse tube 81. A second-stage phase adjusting mechanism 96 is connected to the high temperature end 82H side of the tube 82, respectively.
[0033]
In the above configuration, the working gas flowing through the inside is helium, the working gas has a variable pressure of 0.7 MPa to 2.0 MPa, the temperature at the high temperature end heat exchanger 71a is 300K, and the temperature at the first stage heat exchanger 91 is 60K. The two-stage pulse tube refrigerator 60 is operated so that the temperature in the second-stage heat exchanger 92 is 4.2K. In this case, the working gas inside the first-stage regenerator 71 can be approximated by an ideal gas, but the non-ideality of the working gas appears remarkably at the low temperature end portion of the second-stage regenerator 72. Cannot be approximated.
[0034]
In the above case, for example, if the input work input from the pressure vibration generator 94 is 600 W, the high-temperature end heat exchanger 71a dissipates 600 W of heat, and the regeneration operation of the first-stage regenerator 71 is complete, the low-temperature end The PV illustrated work of the working gas at 71L is 120W. Of the 120 W illustrated work, 100 W is branched into input work to the second-stage regenerator 72 and 20 W is branched into illustrated work on the first-stage pulse tube 81 side. This indicates that the work taken out from the first-stage regenerator 71 is 20 W. In the first stage regenerator 71, the working gas can be regarded as an ideal gas, so 1-T (∂V / ∂T)_P/ V = 0 holds. In this case, since the regeneration action of the first-stage regenerator 71 is complete, an enthalpy flow from the high-temperature end 71H to the low-temperature end 71L of the first-stage regenerator 71 does not occur, and the first-stage regenerator 71 externally The same amount of heat (20 W) as the PV illustrated work taken out is absorbed from the first stage heat exchanger 91. For this reason, the first stage heat exchanger 91 can obtain 20 W of heat absorption.
[0035]
The second stage regenerator 72 is supplied with 100 W of the working gas PV illustrated work (120 W) at the low temperature end 71L of the first stage regenerator 71 that has not been taken out to the outside. Assume that the PV illustrated work of the working gas at the cold end 72L of the vessel 72 is 7W. At the low temperature end 72L of the second stage regenerator 72, the non-ideality of the working gas appears remarkably, so the working gas cannot be approximated to an ideal gas, so | 1-T (∂V / ∂T)_P/V|>0.01. In such a state, even if the regeneration operation of the second-stage regenerator 72 is complete, an enthalpy flow from the high-temperature end 72H to the low-temperature end 72L of the second-stage regenerator 72 occurs, and the low-temperature end 72L The same amount of heat as the PV illustrated work performed by the working gas cannot be absorbed from the second stage heat exchanger 92. For example, when the PV illustrated work of the working gas at the low temperature end 72L is 7 W, the heat absorption amount in the second stage heat exchanger 92 is about 2 W. However, the intermediate heat exchanger 93 is interposed between the low temperature end 72L and the high temperature end 72H of the second stage regenerator 72. Therefore, all or part of the difference (5 W) between the PV illustrated work (7 W) of the working gas at the low temperature end 72L of the second stage regenerator 72 and the heat absorption amount (2 W) in the second stage heat exchanger 92 is The intermediate heat exchanger 93 absorbs heat. Since the intermediate heat exchanger 93 is interposed between the low temperature end 72L and the high temperature end 72H of the second-stage regenerator 72 as described above, the temperature thereof is also the temperature at the low temperature end 72L (4.2K). It is a temperature between the temperature at the high temperature end 72H (60K). For example, when the temperature of this part is set to a temperature of 10 to 20 K, and the working gas can be approximated to an ideal gas by the temperature range and pressure of this part, the low temperature of 10 to 20 K is efficient at the output of 5 W in the part of the intermediate heat exchanger 93. Can be taken out.
[0036]
A two-stage regenerative refrigerator having a two-stage regenerator as described above is, for example, a liquid helium bath in which an object to be cooled, for example, an electronic element, which needs to be cooled in a liquid helium temperature range, It can be used for cooling an electronic device or the like immersed in a liquid helium tank (hereinafter, a cooling object that needs to be cooled in the liquid helium temperature range is called a main cooling object in this paragraph). In addition, in order to prevent heat penetration due to external heat radiation to the main cooling object, a liquid nitrogen tank or a first radiant heat shield plate is provided around the main cooling object to shield external heat intrusion. Yes. However, in order to prevent heat penetration even more reliably, a second radiant heat shield plate may be provided between the main cooling object and the liquid nitrogen tank or the first radiant heat shield plate. In this case, the temperature required for cooling the main cooling object is 4.2K, the temperature required for cooling the liquid nitrogen tank or the first radiant heat shield plate is 60K, and the second radiant heat shield plate is cooled. The required temperature is 10-20K. Therefore, in order to cool such a cooling system, the second stage heat exchanger is used for cooling the main cooling object, and the first stage heat exchanger is used for cooling the liquid nitrogen tank or the first radiant heat shield plate. Then, an intermediate heat exchanger is used for cooling the second radiant heat shield plate. Thereby, it becomes possible to cool the cooling system which needs cooling of three places with a two-stage regenerative refrigerator.
[0037]
The intermediate heat exchanger as described above may be in any position as long as it is between the low temperature end and the high temperature end of the regenerator. By appropriately changing the mounting location of the heat exchanger according to the required temperature range, it is possible to provide a cooling system that meets the required specifications.
[0038]
Further, two or more intermediate heat exchangers as described above may be attached at different positions with respect to one regenerator. A cooling system that meets the required specifications can be provided by appropriately changing the number of installed heat exchangers according to the required temperature range and the number of cooling points.
[0039]
In addition, the regenerator in which the intermediate heat exchanger is interposed only needs to perform the function as a regenerator, and the regenerator may be combined with other components. For example, a piston with a regenerator or a displacer with a built-in regenerator in which a regenerator material is contained in a piston or a displacer has been proposed. Can be thought of as In this case, the high temperature end of the regenerator corresponds to the high temperature end of the regenerator built-in piston or the regenerator built-in displacer, and the low temperature end of the regenerator corresponds to the low temperature end of the regenerator built-in piston or the regenerator built-in displacer. .
[0040]
【Example】
(First embodiment)
FIG. 6 is a cross-sectional view showing a refrigeration generating portion of a two-stage pulse tube refrigerator. In the figure, a refrigeration generating portion 101 of a two-stage pulse tube refrigerator includes a first-stage regenerator 110, a second-stage regenerator 120, a first-stage pulse tube 130, and a second-stage pulse tube 140.
[0041]
The first-stage regenerator 110 includes a first-stage regenerator casing 111 having a space inside, and a first-stage regenerator material 112 filled in the internal space of the first-stage regenerator casing 111. Yes. In this example, a laminated body of copper mesh is used as the first-stage cold storage material 112. The first-stage regenerator 110 includes a low temperature end 110L and a high temperature end 110H. The low temperature end 110L is the lower end of the first stage regenerator 110 in the figure, and the high temperature end 110H is the upper end of the first stage regenerator 110 in the figure. A first passage 113 is formed on the high temperature end 110H side as shown in the figure. One end of the first passage 113 communicates with the upper end portion of the first-stage regenerator material 112 shown in the figure, and the other end opens at the end surface portion of the high temperature end 110H. This opening portion communicates with a pressure vibration generator (not shown). A second passage 114 is also formed on the low temperature end 110L side as shown in the figure. One end of the second passage 114 communicates with the illustrated lower end portion of the first-stage regenerator material 112, and the other end opens to the end surface portion of the low temperature end 110L.
[0042]
The second-stage regenerator 120 includes a second-stage regenerator casing 121 having a space inside. An inner intermediate heat exchanger 125 is attached to the inner space of the second-stage regenerator casing 121, and the inner space of the second-stage regenerator casing 121 is divided into two by the inner intermediate heat exchanger 125. Yes. Of the bisected internal space, the upper space in the drawing is filled with the second-stage high-temperature side cold storage material 122a, and the lower space in the drawing is filled with the second-stage low-temperature side cold storage material 122b. In this example, lead grains are used as the second stage high temperature side cold storage material 122a, and Er is used as the second stage low temperature side cold storage material 122b.₃Ni grains are used. Further, as shown in the figure, a communication passage 126 is formed in the inner intermediate heat exchanger 125, and the communication space 126 allows communication of the divided internal space in the second-stage regenerator casing 121. Has been.
[0043]
An outer intermediate heat exchanger 127 is attached to the outer periphery of the second-stage regenerator casing 121 as shown in the figure. The outer intermediate heat exchanger 127 is attached so as to face the position where the inner intermediate heat exchanger 125 is disposed.
[0044]
The second-stage regenerator 120 includes a low temperature end 120L and a high temperature end 120H. The low temperature end 120 </ b> L is the lower end of the second stage regenerator 120, and the high temperature end 120 </ b> H is the upper end of the second stage regenerator 120. A third passage 123 is formed on the high temperature end 120H side as shown in the figure. One end of the third passage 123 communicates with the illustrated upper end portion of the second-stage high-temperature side cold storage material 122a, and the other end opens at the end surface portion of the high-temperature end 120H. A fourth passage 124 is also formed on the low temperature end 120L side as shown in the figure. One end of the fourth passage 124 communicates with the lower end portion of the second-stage low-temperature side regenerator material 122b, and the other end opens on the side surface of the second-stage regenerator 120 on the low-temperature end 120L side.
[0045]
As shown in the drawing, the opening portion of the second passage 114 formed on the low temperature end 110L side of the first stage regenerator 110 and the third passage 123 formed on the high temperature end 120H side of the second stage regenerator 120 are shown. Both regenerators 110 and 120 are disposed so as to face each other with the opening. Therefore, the high-temperature end 120H of the second-stage regenerator 120 is thermally coupled to the low-temperature end 110L of the first-stage regenerator 110, and the internal space of the first-stage regenerator casing 111 and the second-stage regenerator The internal space of the vessel casing 121 can communicate with the third passage 114 and the fourth passage 123.
[0046]
The third passage 123 formed at the high temperature end 120H of the second stage regenerator 120 is connected to the branch passage 128 from the middle thereof. This branch passage 128 opens on the side surface of the second stage regenerator 120 on the high temperature end 120H side.
[0047]
The first stage pulse tube 130 is a hollow cylindrical tube formed of stainless steel or the like. The first stage pulse tube 130 includes a low temperature end 130L and a high temperature end 130H. The low temperature end 130L is the lower end of the first stage pulse tube 130 in the figure, and the high temperature end 130H is the upper end of the first stage pulse tube 130 in the figure. As shown in the figure, rectifying plates 131 and 131 are attached to both ends 130L and 130H, and the rectifying plates 131 and 131 rectify the working gas flowing into the first-stage pulse tube 130.
[0048]
A first high temperature side heat exchanger 132 is attached to the first stage pulse tube 130 so as to cover the high temperature end 130H. The first high temperature end heat exchanger 132 plays a role of cooling the portion of the high temperature end 130H of the first stage pulse tube 130 by making thermal contact with the outside air or exchanging heat with the cooling water. A fifth passage 133 is formed in the first high temperature heat exchanger 132. One end of the fifth passage 133 communicates with the high temperature end 130H of the first-stage pulse tube 130, and the other end opens at the end surface portion of the first high temperature heat exchanger 132 as shown in the figure. This opening portion communicates with a phase adjusting mechanism (not shown).
[0049]
A first-stage heat exchanger 134 is attached to the low-temperature end 130L side of the first-stage pulse tube 130 so as to cover the low-temperature end 130L. The first stage heat exchanger 134 plays a role of cooling the object to be cooled by being in thermal contact with the object to be cooled, and can generate a low temperature of about 60K in this example. In the first stage heat exchanger 134, as shown in the figure, a sixth passage 135 is formed. One end of the sixth passage 135 communicates with the low temperature end 130 </ b> L of the first stage pulse tube 130, and the other end opens on the side surface of the first stage heat exchanger 134.
[0050]
The sixth passage 135 opened on the side surface of the first stage heat exchanger 134 and the branch passage 128 opened on the side surface on the high temperature end 120H side of the second stage regenerator 120 are connected by a communication pipe 136. Therefore, the working gas in the first-stage regenerator 110 can communicate with the first-stage pulse tube 130 through the second passage 114, the third passage 123, the branch passage 128, the communication pipe 136, and the sixth passage 135. It is said that.
[0051]
Like the first-stage pulse tube 130, the second-stage pulse tube 140 is a hollow cylindrical tube formed of stainless steel or the like. The second stage pulse tube 140 includes a low temperature end 140L and a high temperature end 140H. The low temperature end 140L is the lower end of the second stage pulse tube 140 in the figure, and the high temperature end 140H is the upper end of the second stage pulse tube 140 in the figure. As shown in the drawing, rectifying plates 141 and 141 are attached to both ends 140L and 140H, and the working gas flowing into the second-stage pulse tube 140 is rectified by these rectifying plates 141 and 141.
[0052]
A second high temperature side heat exchanger 142 is attached to the second stage pulse tube 140 so as to cover the high temperature end 140H. The second high-temperature end heat exchanger 142 plays a role of cooling the portion of the high-temperature end 140H of the second-stage pulse tube 140 by making thermal contact with outside air or exchanging heat with cooling water. A seventh passage 143 is formed inside the second high-temperature heat exchanger 142. One end of the seventh passage 143 communicates with the high temperature end 140H of the second stage pulse tube 140, and the other end opens to the end surface portion of the second high temperature heat exchanger 142 as shown in the figure. This opening portion communicates with a phase adjusting mechanism (not shown).
[0053]
A second-stage heat exchanger 144 is attached to the low-temperature end 140L side of the second-stage pulse tube 140 so as to cover the low-temperature end 140L. The second-stage heat exchanger 144 plays a role in cooling the object to be cooled by being in thermal contact with the object to be cooled, and can generate a low temperature of about 4.2 K in this example. As shown in the drawing, an eighth passage 145 is formed in the second stage heat exchanger 144. One end of the eighth passage 145 communicates with the low temperature end 140L of the second stage pulse tube 140, and the other end opens to the side surface of the second stage heat exchanger 144.
[0054]
The eighth passage 145 opened on the side surface of the second stage heat exchanger 144 and the fourth passage 124 opened on the side surface on the low temperature end 120L side of the second stage regenerator 120 are connected by a communication pipe 146. Therefore, the working gas in the second-stage regenerator 120 can communicate with the second-stage pulse tube 140 through the fourth passage 124, the communication pipe 146, and the eighth passage 145.
[0055]
In the two-stage pulse tube refrigerator having the refrigeration generating portion 101 having the above configuration, helium gas is used as the working gas, and a pressure vibration generator (not shown) is driven. Then, in this pressure vibration generator, low pressure and high pressure are alternately generated to cause pressure vibration. Since the pressure vibration generator communicates with the first passage 113 as described above, this pressure vibration is The generated portion 101 is transmitted. Further, along with such pressure vibration, the working gas reciprocates inside the refrigeration generating portion 101. At this time, a phase difference is generated between the displacement of the working gas in the first-stage pulse tube 130 and the second-stage pulse tube 140 and the pressure fluctuation by a phase adjusting mechanism (not shown). By setting this phase difference to about 90 ° at the low temperature ends 130L and 140L of the pulse tubes 130 and 140, the working gas adiabatically expands at the low temperature ends 130L and 140L of the pulse tubes 130 and 140, thereby Is generated. Due to this pressure fluctuation and displacement, heat is pumped up from the low temperature ends 110L, 120L of the regenerators 110, 120 toward the high temperature ends 110H, 120H. For this reason, cold is generated at the low temperature ends 130L and 140L of the pulse tubes 130 and 140, respectively. This cold is transmitted to the first stage heat exchanger 134 and the second stage heat exchanger 144 to cool the object to be cooled which is thermally coupled to the heat exchangers 134 and 144.
[0056]
In the first stage heat exchanger 134, a chill of about 60K is obtained. Further, in the second stage heat exchanger 144, a cooling of about 4.2K is obtained. In this case, the temperature range of the working gas in the first stage regenerator 110 is about 300 K (normal temperature) to 60 K, and the ideality of the working gas is maintained within this temperature range. In other words, the working gas can be regarded as an ideal gas approximately, 1-T (∂V / ∂T)_P/ V = 0 holds. Therefore, if the enthalpy flow from the high temperature end 110H of the first stage regenerator 110 to the low temperature end 110L does not occur and the regeneration action of the first stage regenerator 110 is complete, the first stage branched from the low temperature end 110L. The same amount of heat as the PV illustrated work of the working gas to the low temperature end 130L of the pulse tube 130 is absorbed by the first stage heat exchanger 134 attached to the low temperature end 130L of the first stage pulse tube 130. For example, when the PV illustrated work of the working gas branched from the low temperature end 110L of the first stage regenerator 110 to the first stage pulse tube 130 is 20 W, the heat absorption amount in the first stage heat exchanger 134 is also 20 W. Therefore, the first stage heat exchanger 134 can obtain a refrigeration output of 60K and 20W.
[0057]
On the other hand, the temperature at the low temperature end 120L of the second stage regenerator 120 is 4.2K, and the temperature at the high temperature end 120H is about 60K. In this case, the non-ideality of the working gas is prominent in the vicinity of the low temperature end 120L, and | 1-T (∂V / ∂T)_P/V|>0.01. In such a state, even if the regeneration action of the second-stage regenerator 120 is complete, an enthalpy flow from the high-temperature end 120H to the low-temperature end 120L of the second-stage regenerator 120 is generated. The same amount of heat as the PV illustrated work performed by the working gas cannot be absorbed from the second stage heat exchanger 144. For example, when the PV illustrated work of the working gas at the low temperature end 120L is 7 W, the heat absorption amount in the second stage heat exchanger 144 is about 2 W. Therefore, the second stage heat exchanger 144 can obtain a refrigeration output of 4.2K and 2W.
[0058]
In this case, the endothermic heat can also be obtained by the outer intermediate heat exchanger 127 and the inner intermediate heat exchanger 125 interposed between the low temperature end 120L and the high temperature end 120H. The endothermic amount is influenced by the non-ideality of the working gas in that part, but if the working gas in this part can be approximated as an ideal gas, an endotherm of 5 W can be expected. Therefore, when the temperature in the heat exchangers 125 and 127 is 20K and the working gas is ideal, a refrigeration output of 20K and 5W can be obtained in this portion.
[0059]
(Second embodiment)
FIG. 7 is a cross-sectional view showing a refrigeration generating portion of the two-stage GM refrigerator. In the figure, the refrigeration generating part 201 of the two-stage GM refrigerator includes a first-stage cylinder 210, a first-stage regenerator built-in displacer 220, a second-stage cylinder 230, and a second-stage regenerator built-in displacer 240.
[0060]
The first-stage cylinder 210 is formed in a cylindrical shape, and a communication hole 211 for introducing and discharging working gas and an insertion hole 212 for inserting a rod are formed on the upper end surface in the figure. The communication hole 211 communicates with a pressure vibration generator (not shown). A rod described below is inserted through the insertion hole 212.
[0061]
The first-stage regenerator built-in displacer 220 is disposed inside the first-stage cylinder 210 so as to reciprocate. The first-stage regenerator built-in displacer 220 includes a first-stage displacer case 221 having an internal space and a first-stage regenerator material 222 filled in the internal space of the first-stage displacer case 221. Yes. The material of the first-stage regenerator material 222 is the same as that in the first embodiment.
[0062]
The first-stage regenerator built-in displacer 220 includes a low temperature end 220L and a high temperature end 220H. The low temperature end 220L is a lower end of the first stage displacer 220 in the figure, and the high temperature end 220H is an upper end of the first stage displacer 220 in the figure. As shown in the figure, a back space S is formed between the high-temperature end 220H of the first-stage regenerator built-in displacer 220 and the illustrated upper inner wall of the first-stage cylinder 210, and the low-temperature of the first-stage regenerator built-in displacer 220 is low. A first-stage expansion space V <b> 1 is formed between the end 220 </ b> L and the illustrated lower inner wall of the first-stage cylinder 210.
[0063]
One end of a rod 229 is connected to the high temperature end 220H of the first stage regenerator built-in displacer 220. The rod 229 protrudes from the high temperature end 220H of the first stage displacer 220 through the insertion hole 212 formed in the first stage displacer case 221. The other end of the rod 229 is connected to a reciprocating drive means (not shown).
[0064]
As shown in the figure, a first communication path 223 is formed on the high temperature end 220H side of the first-stage regenerator built-in displacer 220. One end of the first communication path 223 communicates with the upper end portion of the first-stage regenerator material 222 and the other end opens at the end surface portion of the high temperature end 220H and communicates with the back space S. On the other hand, a second communication path 224 is formed on the low temperature end 220L side. One end of the second communication path 224 communicates with the lower end edge portion of the first-stage regenerator material 222 and the other end opens to the side surface of the first-stage displacer case 221 to enter the first-stage expansion space V1. Communicate. A displacer ring 225 is attached to the outer periphery of the first stage displacer case 221. The displacer ring 225 is for filling a gap between the first-stage displacer case 221 and the inner wall of the first-stage cylinder 210 and preventing the working gas from flowing through the gap. It is attached to the position which shields the direct communication with the opening part of this, and the opening part of the 2nd communicating path 224. Accordingly, the working gas introduced into the back space V1 from the communication hole 211 enters the space filled with the first stage regenerator material 222 from the high temperature end 220H side of the first stage regenerator built-in displacer 220 through the first communication path 223. Enter and pass through the second communication passage 224 to reach the first-stage expansion space V2. At this time, due to the presence of the displacer ring 225, the working gas in the back space V1 cannot escape to the first-stage expansion space V2 through the gap between the first-stage displacer case 221 and the inner wall of the first-stage cylinder 210. Therefore, the working gas in the back space V1 does not escape directly to the first stage expansion space V2 without passing through the first stage regenerator material 222.
[0065]
The illustrated lower end portion of the first-stage cylinder 210 is opened in a circular shape. The upper end opening of the second stage cylinder 230 is connected to the opening edge.
[0066]
The second-stage cylinder 230 is formed in a cylindrical shape having a smaller diameter than the first-stage cylinder 210. The upper end surface of the second-stage cylinder 230 is opened and connected to the lower end opening edge of the first-stage cylinder 210 as described above. Yes. Moreover, the lower end surface shown in the figure is closed.
[0067]
The second-stage regenerator built-in displacer 240 is disposed inside the second-stage cylinder 230 so as to be able to reciprocate. The second-stage displacer 240 includes a second-stage displacer case 241 having a space inside. An inner intermediate heat exchanger 246 is attached to the inner space of the second stage displacer case 241, and the inner space of the second stage displacer case 241 is divided into two by this inner intermediate heat exchanger 246. Of the bisected internal space, the upper space in the drawing is filled with the second-stage high-temperature side cold storage material 242a, and the lower space in the drawing is filled with the second-stage low-temperature side cold storage material 242b. These regenerator materials are the same as in the first embodiment. Further, the inner intermediate heat exchanger 246 is formed with a communication path 247 as shown in the figure, and the communication path 247 enables communication between the divided internal space in the second-stage displacer case 241. ing.
[0068]
An outer intermediate heat exchanger 248 is attached to the outer periphery of the second stage cylinder 230 as shown in the figure. The outer intermediate heat exchanger 248 is attached so as to substantially face the position where the inner intermediate heat exchanger 247 is disposed.
[0069]
The second-stage regenerator built-in displacer 240 includes a low temperature end 240L and a high temperature end 240H. The low temperature end 240 </ b> L is the lower end of the second stage regenerator built-in displacer 240 and the high temperature end 240 </ b> H is the upper end of the second stage displacer 240. The high-temperature end 240H side portion of the second-stage regenerator built-in displacer 240 is fitted into the low-temperature end 220L side portion of the first-stage displacer 220, whereby the high-temperature end 240H and the low-temperature end 220L are thermally connected. In addition, both displacers 220 and 240 are made to operate as a unit. A second-stage expansion space V <b> 2 is formed between the low-temperature end 240 </ b> L of the second-stage regenerator built-in displacer 240 and the illustrated lower wall of the second-stage cylinder 230.
[0070]
As shown in the drawing, a third communication path 243 is formed on the high temperature end 240H side. One end of the third communication path 243 communicates with the upper end portion of the second-stage high-temperature regenerator material 242a shown in the figure, and the other end opens to the side surface portion of the second-stage displacer case 221 to open the first-stage expansion space V2. Communicating with On the other hand, a fourth communication passage 244 is formed on the low temperature end 240L side. One end of the fourth communication path 244 communicates with the lower end portion of the second-stage low-temperature regenerator material 242b, and the other end opens to the side surface of the second-stage displacer case 241 to enter the second-stage expansion space V3. Communicate. A displacer ring 245 is attached to the outer periphery of the second-stage displacer case 241. The displacer ring 245 fills the gap between the second-stage displacer case 241 and the inner wall of the second-stage cylinder 230 and prevents the working gas from flowing through the gap. Are attached to a position between the opening portion of the fourth communication path 244 and the opening portion of the fourth communication passage 244. Accordingly, the working gas in the first-stage expansion space V2 enters the space filled with the second-stage high-temperature regenerator material 242a via the third communication path 243, and further passes through the communication path 247 of the inner intermediate heat exchanger 246 to 2 It enters the space filled with the stage low-temperature regenerator material 242b, and reaches the second stage expansion space V3 through the fourth communication passage 244 therefrom. At this time, due to the presence of the displacer ring 245, the working gas in the first stage expansion space V2 passes through the gap between the second stage displacer case 241 and the inner wall of the second stage cylinder 230 and escapes to the second stage expansion space V3. Therefore, the working gas in the first stage expansion space V2 does not go directly to the second stage expansion space V3 without passing through the second stage high temperature side cold storage material 242a and the second stage low temperature side cold storage material 242b.
[0071]
A first stage heat exchanger 254 is attached to the outer periphery of the first stage cylinder 210 so as to cover the first stage expansion space V <b> 2 inside the cylinder 210. The first-stage heat exchanger 254 plays a role of cooling the object to be cooled by being in thermal contact with the object to be cooled, and can generate a low temperature of about 60K in this example. A second-stage heat exchanger 255 is attached to the outer periphery of the second-stage cylinder 230 so as to cover the second-stage expansion space V3 inside the cylinder 230. The second stage heat exchanger 255 plays a role of cooling the object to be cooled by being in thermal contact with the object to be cooled, and can generate a low temperature of about 4.2K in this example.
[0072]
In the two-stage GM refrigerator having the refrigeration generating portion 201 having the above configuration, helium gas is used as the working gas, and a pressure vibration generator (not shown) is driven. Then, in this pressure vibration generator, low pressure and high pressure are alternately generated to cause pressure vibration. However, since the pressure vibration generator communicates with the communication hole 211 as described above, this pressure vibration is generated by freezing. Transmitted to portion 201. Along with the driving of the pressure vibration generator, a reciprocating driving means (not shown) is also driven. Then, the driving force from the reciprocating driving means is transmitted to the rod 229, and the first-stage regenerator built-in displacer 220 connected to the rod 229 and the second-stage regenerator connected to the first-stage regenerator built-in displacer 220. The built-in displacer 240 reciprocates in the first-stage cylinder 210 and the second-stage cylinder 230 in the direction indicated by the arrows. At this time, by operating the pressure oscillation of the working gas and the reciprocating driving of both displacers 220 and 240 so as to have a phase difference of 90 °, the working gas is adiabatically expanded in each of the expansion spaces V2 and V3, thereby And the heat is pumped from the low temperature ends 220L and 240L of the displacers 220 and 240 toward the high temperature ends 220H and 240H. Therefore, the first-stage heat exchanger 254 and the second-stage heat exchanger 255 attached so as to cover the expansion spaces V2 and V3 are cooled, and the heat exchangers 254 and 255 are thermally coupled to the heat exchangers 254 and 255. Cool the cooling body.
[0073]
In the first stage heat exchanger 254, a chill of about 60K is obtained. Further, in the second stage heat exchanger 255, a cooling of about 4.2K is obtained. In this case, the temperature range of the working gas in the first-stage regenerator built-in displacer 220 is about 300 K (normal temperature) to 60 K, and the ideality of the working gas is maintained within this temperature range. In other words, the working gas can be regarded as an ideal gas approximately, 1-T (∂V / ∂T)_P/ V = 0 holds. Therefore, if the regenerator regeneration action of the first-stage regenerator built-in displacer 220 is complete, the enthalpy flow from the high-temperature end 220H to the low-temperature end 220L of the first-stage regenerator built-in displacer 220 does not occur. The same amount of heat as the PV illustrated work of the working gas in the expansion space V2 is absorbed by the first stage heat exchanger 254. For example, when the PV illustrated work of the working gas in the first stage expansion space V2 is 20 W, the heat absorption amount in the first stage heat exchanger 254 is also 20 W. Therefore, the first-stage heat exchanger 254 can obtain a refrigeration output of 60K and 20W.
[0074]
On the other hand, the temperature range of the working gas in the second-stage regenerator built-in displacer 240 is 60K on the high temperature end 240H side and 4.2K on the low temperature end 240L side. In this case, the working gas significantly exhibits non-ideality on the low temperature end 240L side, and | 1-T (∂V / ∂T)_P/V|>0.01. In such a state, an enthalpy flow from the high-temperature end 240H of the second-stage regenerator built-in displacer 240 to the low-temperature end 240L occurs, and the regenerator regeneration operation of the second-stage regenerator built-in displacer 240 is complete. However, the second stage heat exchanger 255 cannot absorb the same amount of heat as the PV illustrated work performed by the working gas in the second stage expansion space V3. For example, when the PV illustrated work of the working gas in the second stage expansion space V3 is 7 W, the heat absorption amount in the second stage heat exchanger 255 is about 2 W. Therefore, in the second stage heat exchanger 255, 4.2K, 2W refrigeration output can be obtained.
[0075]
In this case, heat absorption is also obtained in the outer intermediate heat exchanger 248 and the inner intermediate heat exchanger 246 interposed between the low-temperature end 240L and the high-temperature end 240H of the second-stage regenerator built-in displacer 240. The endothermic amount is influenced by the non-ideality of the working gas in that part, but if the working gas in this part can be approximated as an ideal gas, an endotherm of 5 W can be expected. Therefore, if the temperature in the heat exchangers 246 and 248 is 20K and the working gas is ideal, a refrigeration output of 20K and 5W can be obtained in this portion.
[0076]
The two-stage GM refrigerator as described above has fewer components than the two-stage pulse tube refrigerator shown in the first embodiment. For example, the pulse tube shown in the first embodiment and the connection piping for connecting it are not required. Therefore, the present invention can be realized with a simple configuration, and a highly efficient and reliable refrigerator can be provided.
[0077]
(Third embodiment)
In the two-stage GM refrigerator shown in the second embodiment, the above-mentioned output can be obtained in theory, but actually, it is more than the two-stage pulse tube refrigerator shown in the first embodiment. Refrigeration output is inferior. As is apparent from FIG. 7, the reason is that between the inner intermediate heat exchanger 246 and the outer intermediate heat exchanger 248, the side surface of the displacer 240 with the second-stage regenerator and the inner peripheral wall on the second-stage cylinder side are provided. Since there is a gap (gap) L between them, and heat transfer through the gas layer in the gap L is poor, the cold obtained by the inner intermediate heat exchanger 246 is reliably transmitted to the outer intermediate heat exchanger 248. This is because the desired refrigeration output cannot be taken out.
[0078]
This example shows such a two-stage GM refrigerator with improved defects.
[0079]
FIG. 8: is sectional drawing of the freezing generation | occurrence | production part of the two-stage GM refrigerator concerning 3rd Example. The refrigeration generating portion 261 is basically the same as the refrigeration generating portion 201 shown in FIG. 7, and the only difference is the portion of the displacer with a built-in second-stage regenerator. The following description will focus on the different parts, and the same parts will be denoted by the same reference numerals as those shown in FIG.
[0080]
In FIG. 8, two displacer rings, a first displacer ring 245a and a second displacer ring 245b, are attached to the outer periphery of the displacer 240 with a built-in second-stage regenerator. For this reason, in the gap L between the side surface of the second-stage regenerator built-in displacer 240 and the inner peripheral wall of the second-stage cylinder 230, the portion sandwiched between the displacer rings 245a and 245b is defined as a sealed space K. Yes.
[0081]
The space filled with the second-stage high-temperature side cold storage material 242a in the second-stage regenerator built-in displacer 240 communicates with the sealed space K through the third communication path 247a. A second communication path 247b is formed in the inner intermediate heat exchanger 246. One end of the second communication path 247b communicates with the upper end of the second-stage low-temperature regenerator material 242b, and the other end of the second communication path 247b. The second-stage displacer case 241 opens to the side surface and communicates with the sealed space K. Accordingly, the working gas in the space filled with the second-stage high-temperature side cold storage material 242a enters the sealed space K through the first communication path 247a and passes through the second communication path 247b from the sealed space K. It will be introduced into the space filled with the second stage low temperature side cold storage material 242b.
[0082]
Therefore, when the area of the sealed space K is designed to be located at the facing portion between the outer intermediate heat exchanger 248 and the inner intermediate heat exchanger 246, the working gas enters and exits the sealed space K during the operation of the refrigerator. Therefore, forced convection occurs in this part. For this reason, convective heat transfer is promoted, the heat transfer coefficient between the inner intermediate heat exchanger 246 and the outer intermediate heat exchanger 248 is increased, and the refrigeration output (heat absorption amount) in the outer intermediate heat exchanger 248 is improved. Can be made.
[0083]
(Fourth embodiment)
FIG. 9: is sectional drawing which shows the freezing generation | occurrence | production part of the two-stage type GM refrigerator concerning 4th Example of this invention. This example is a configuration that prevents a decrease in heat transfer due to the presence of a gap between the side surface of the displacer and the inner peripheral wall of the cylinder, as seen in the second and third embodiments. 9, the first stage cylinder and the first stage regenerator built-in displacer are basically the same as those shown in FIG. 7, except for the second stage cylinder and the second stage cylinder. This is the configuration of the stage displacer. The following description will focus on the differences, and the same components as those in FIG.
[0084]
In FIG. 9, the refrigeration generating part 301 of the two-stage GM refrigerator includes a first-stage cylinder 210, a first-stage regenerator built-in displacer 220, a second-stage cylinder 230, a second-stage displacer 260, and a second-stage regenerator 270. It comprises.
[0085]
The first stage cylinder 210 is basically the same as the first stage cylinder 210 shown in FIGS. However, it differs from the case of FIG.7 and FIG.8 in that the communication hole 213 is formed in the illustrated lower end surface of the first stage cylinder 210 as shown in the figure. The other parts that are the same as those in FIGS.
[0086]
The first-stage regenerator built-in displacer 220 is disposed so as to reciprocate within the first-stage cylinder 210. Then, the back space S is formed by the high temperature end 220H of the first stage displacer 220 and the upper inner wall surface of the first stage cylinder, and the low temperature end 220L of the first stage cooler built-in displacer 220 and the lower inner wall surface of the first stage cylinder. And the first-stage expansion space V1 are respectively defined. The basic configuration of the first-stage regenerator built-in displacer 220 is the same as that of the first-stage regenerator built-in displacer 220 shown in FIGS. Description is omitted.
[0087]
The configuration of the second stage cylinder 230 is basically the same as that of the second stage cylinder 230 shown in FIGS. However, the second stage cylinder 230 differs from the second stage cylinder 230 shown in FIGS. 7 and 8 in that a communication hole 231 is formed on the side surface of the second stage cylinder 230 as shown in the figure. Other parts that are the same as those shown in FIGS.
[0088]
The second stage displacer 260 is disposed inside the second stage cylinder 230 so as to be able to reciprocate. The second-stage displacer 260 is formed of a cylindrical solid member, and unlike the second-stage displacer 230 shown in FIGS. 7 and 8, does not incorporate a regenerator material therein. The upper end of the second stage displacer 260 is connected to the low temperature end 220L of the first stage displacer 220. Accordingly, the second-stage displacer 260 operates integrally with the first-stage displacer 220. A second-stage expansion space V <b> 2 is defined between the illustrated lower end of the second-stage displacer 260 and the illustrated lower inner wall surface of the second-stage cylinder 230. The second stage displacer 260 is a solid member in this example, but may be a hollow member as long as the working gas does not flow into and out of the inside. From the viewpoint of weight reduction, a hollow one is preferable.
[0089]
A second-stage regenerator 270 is disposed on the outer periphery of the second-stage cylinder 230. The second-stage regenerator 270 includes a regenerator case 271, a second-stage high-temperature side regenerator material 272a, and a second-stage low-temperature side regenerator material 272b. The regenerator case 271 is formed in a ring shape so as to surround the outer periphery of the second-stage cylinder 230. In addition, an inner intermediate heat exchanger 273 is disposed in a space between the regenerator case 271 and the second-stage cylinder 230, and the inner intermediate heat exchanger 273 divides the space into two. . Of the divided space, the upper space in the drawing is filled with the second-stage high-temperature side cold storage material 272a, and the lower space in the drawing is filled with the second-stage low-temperature side cold storage material 242b. The inner intermediate heat exchanger 273 has a communication passage 274 as shown in the figure. The communication passage 274 bisects the space, that is, the space filled with the second-stage high-temperature side regenerator material. And a space filled with the second-stage low-temperature side regenerator material can be communicated with each other.
[0090]
An outer intermediate heat exchanger 275 is attached to the outer periphery of the regenerator case 271 as shown in the figure. The outer intermediate heat exchanger 275 is attached so as to substantially face the position where the inner intermediate heat exchanger 274 is disposed.
[0091]
The second stage regenerator 270 includes a low temperature end 270L and a high temperature end 270H. The low temperature end 270L is the lower end of the second stage regenerator 270 in the figure, and the high temperature end 270H is the upper end of the second stage regenerator 270 in the figure. The high temperature end 270H faces a communication hole 213 formed at the lower end of the first stage cylinder 210 in the figure, and is thermally connected to the low temperature end 220L of the first stage regenerator built-in displacer 220 through the first stage expansion space V1. Is bound to. On the other hand, the portion near the low temperature end 270L communicates with a communication hole 231 formed in the second-stage cylinder 230 as shown in the figure. Therefore, the working gas in the first-stage expansion space V1 enters the space filled with the second-stage high-temperature regenerator material 272a through the communication hole 213, and further passes through the communication passage 274 of the inner intermediate heat exchanger 273 to form the second stage. It can enter the space filled with the low-temperature cold storage material 272b, and can reach the second-stage expansion space V2 through the communication hole 231 therefrom. In this case, since the displacer ring 275 is attached to the gap between the second-stage displacer 260 and the inner wall of the second-stage cylinder 230, the presence of the displacer ring 275 causes the first-stage expansion space V1 to The working gas cannot escape through the gap between the second stage displacer 260 and the inner wall of the second stage cylinder 230 into the second stage expansion space V2. Therefore, the working gas in the first-stage expansion space V1 does not escape directly to the second-stage expansion space V2 without passing through the second-stage high-temperature side cold storage material 272a and the second-stage low-temperature side cold storage material 272b.
[0092]
A first stage heat exchanger 254 is attached to the outer periphery of the first stage cylinder 210 so as to cover the first stage expansion space V <b> 1 inside the cylinder 210. The first-stage heat exchanger 254 plays a role of cooling the object to be cooled by being in thermal contact with the object to be cooled, and can generate a low temperature of about 60K in this example. A second-stage heat exchanger 255 is attached to the outer periphery of the second-stage cylinder 230 so as to cover the second-stage expansion space V2 inside the cylinder 230. The second stage heat exchanger 255 plays a role of cooling the object to be cooled by being in thermal contact with the object to be cooled, and can generate a low temperature of about 4.2K in this example.
[0093]
In this example, as apparent from the above configuration, the second-stage displacer 260 and the second-stage regenerator 270 are separated, and the separated second-stage regenerator 270 is ring-shaped around the outer periphery of the second-stage displacer 260. The inner intermediate heat exchanger 273 is formed inside the ring-shaped second-stage regenerator 270 and the outer intermediate heat exchanger 275 is attached to the outer periphery thereof. A gap with the exchanger 275 can be eliminated. For this reason, compared with the said 2nd and 3rd Example, the heat transfer between the outer side intermediate heat exchanger 275 and the inner side intermediate heat exchanger 273 becomes favorable, and the heat absorption amount obtained with the outer side intermediate heat exchanger 275 Can be increased.
[0094]
As mentioned above, although the Example of this invention was described, this invention is not limited to the said Example. For example, in the above-described embodiments, the two-stage type regenerative refrigerator has been described, but an intermediate heat exchanger is interposed between the low-temperature end and the high-temperature end of the third-stage regenerator of the three-stage regenerative refrigerator. It is also possible to use a configuration. Even in the case of a single-stage regenerative refrigerator, if the non-ideality of the working gas appears remarkably inside the regenerator, an intermediate heat exchanger is installed between the low temperature end and the high temperature end of the regenerator. An intervening configuration may be used. If it is intended to obtain a cold of about 4K using helium gas, it is difficult to obtain 4K with a single-stage regenerative refrigerator at this stage, but if this is possible, Even if an intermediate heat exchanger is interposed between the low temperature end and the high temperature end of the regenerator of such a single-stage regenerative refrigerator, it is possible to efficiently obtain heat absorption.
[0095]
【The invention's effect】
As described above, according to the present invention, the problems caused by the multistage refrigerating type refrigerator, for example, the increase in design time due to the complexity of the configuration, and the space problem due to the increase in the size of the entire apparatus. It is possible to eliminate the cost problem and efficiently obtain the heat absorption.
[Brief description of the drawings]
FIG. 1 is a regenerator with a cold end temperature of 60K and a hot end temperature of 300K, and when an intermediate heat exchanger is not installed, the PV illustrated work of the working gas at the cold end and the absorption at the cold end heat exchanger It is a schematic diagram which shows the relationship with a calorie | heat amount.
[Fig. 2] A regenerator with a low temperature end temperature of 4.2K and a high temperature end temperature of 60K, with PV illustrated work of the working gas at the low temperature end and a low temperature end heat exchanger when no intermediate heat exchanger is installed. It is a schematic diagram which shows the relationship with the amount of heat absorption.
FIG. 3 shows the PV illustrated work of the working gas at the low temperature end and the low temperature end when the intermediate heat exchanger is installed in the regenerator having the low temperature end temperature of 4.2K and the high temperature end temperature of 60K. It is a schematic diagram which shows the relationship between the heat absorption in a heat exchanger and an intermediate heat exchanger.
FIG. 4 is a regenerator with a low temperature end temperature of 60K and a high temperature end temperature of 300K, and when an intermediate heat exchanger is installed, the PV illustrated work of the working gas at the low temperature end, the low temperature end heat exchanger, and the intermediate heat It is a schematic diagram which shows the relationship with the heat absorption amount in an exchanger.
FIG. 5 shows a PV illustrated work of a working gas and a low-temperature end heat exchanger at a low-temperature end of each regenerator in a first-stage regenerator and a second-stage regenerator of a two-stage pulse tube refrigerator to which the present invention is applied. It is a schematic diagram which shows the relationship with the endothermic amount in an intermediate heat exchanger.
FIG. 6 is a cross-sectional view of a refrigeration generating portion of a two-stage pulse tube refrigerator in the first embodiment of the present invention.
FIG. 7 is a cross-sectional view of a refrigeration generating portion of a two-stage GM refrigerator in a second embodiment of the present invention.
FIG. 8 is a cross-sectional view of a refrigeration generating portion of a two-stage GM refrigerator in a third embodiment of the present invention.
FIG. 9 is a cross-sectional view of a portion where freezing occurs in a two-stage GM refrigerator in a fourth embodiment of the present invention.
[Explanation of symbols]
30 ... Regenerator, 30L ... Low temperature end, 30H ... High temperature end
31L ... low temperature end heat exchanger, 31L ... low temperature end heat exchanger
50 ... Intermediate heat exchanger
Pulse tube, 30L ... Pulse tube cold end (cold end), 30H ... Pulse tube hot end (hot end)
60 ... Two-stage pulse tube refrigerator (regenerative refrigerator)
71 ... 1st stage regenerator, 71L ... low temperature end, 71H ... high temperature end
72 ... second stage regenerator, 72L ... low temperature end, 72H ... high temperature end
81: first stage pulse tube, 81L: low temperature end, 81H: high temperature end
82 ... second stage pulse tube, 82L ... low temperature end, 82H ... high temperature end
91 ... 1st stage heat exchanger
92 ... 2nd stage heat exchanger
93 ... Intermediate heat exchanger
101 ... Two-stage pulse tube refrigerator
110 ... first stage regenerator, 110L ... low temperature end, 110H ... high temperature end
120 ... second stage regenerator, 120L ... low temperature end, 120H ... high temperature end
125, 246, 273 ... Inner intermediate heat exchanger
127, 248, 275 ... Outer intermediate heat exchanger
130 ... 1st stage pulse tube
140 ... 2nd stage pulse tube
134, 254 ... 1st stage heat exchanger
144, 255 ... 2nd stage heat exchanger
201, 261, 301 ... Two-stage GM refrigerator
220 ... Displacer with built-in first stage regenerator (first stage regenerator), 220L ... low temperature end, 220H ... high temperature end
240 ... Displacer with built-in second stage regenerator (second stage regenerator), 240L ... low temperature end, 240H ... high temperature end
270 ... second stage regenerator, 270L ... low temperature end, 270H ... high temperature end

Claims (5)

In a regenerative refrigerator that uses a regenerator having a low temperature end and a high temperature end, and generates cold by pumping heat from the low temperature end side to the high temperature end side when the working gas reciprocates the regenerator,
The regenerator has a first stage regenerator having a low temperature end and a high temperature end, and a second stage regenerator having a low temperature end and a high temperature end thermally coupled to the low temperature end of the first stage regenerator, An intermediate heat exchanger is interposed between the low temperature end and the high temperature end of the second stage regenerator,
The helium gas is used as the working gas, and the regenerative refrigerator is operated so that the temperature at the low temperature end of the second-stage regenerator is 2 to 10 K, and heat loss due to the non-ideality of the helium gas Heat is absorbed from the intermediate heat exchanger,
The intermediate heat exchanger includes an inner intermediate heat exchanger disposed inside the second-stage regenerator, and an outer intermediate heat exchanger disposed outside the second-stage regenerator. The inner intermediate heat exchanger and the outer intermediate heat exchanger are respectively arranged in a substantially facing positional relationship,
Comprising a displacer which incorporates the intermediate heat exchanger and the second-stage regenerator, and a second-stage cylinder in which the displacer reciprocates,
Forming a gap between the side surface of the displacer and the inner peripheral wall of the second stage cylinder;
The working gas in the space on the high temperature end side of the second-stage regenerator material enters the gap and is introduced into the space on the low-temperature end side of the second-stage regenerator material from the gap. Type refrigerator. In a regenerative refrigerator that uses a regenerator having a low temperature end and a high temperature end, and generates cold by pumping heat from the low temperature end side to the high temperature end side when the working gas reciprocates the regenerator,
The regenerator has a first stage regenerator having a low temperature end and a high temperature end, and a second stage regenerator having a low temperature end and a high temperature end thermally coupled to the low temperature end of the first stage regenerator, An intermediate heat exchanger is interposed between the low temperature end and the high temperature end of the second stage regenerator,
The helium gas is used as the working gas, and the regenerative refrigerator is operated so that the temperature at the low temperature end of the second-stage regenerator is 2 to 10 K, and heat loss due to the non-ideality of the helium gas Heat is absorbed from the intermediate heat exchanger,
The intermediate heat exchanger includes an inner intermediate heat exchanger disposed inside the second-stage regenerator, and an outer intermediate heat exchanger disposed outside the second-stage regenerator. The inner intermediate heat exchanger and the outer intermediate heat exchanger are respectively arranged in a substantially facing positional relationship,
A displacer for reciprocating the working gas between the second-stage regenerator and the intermediate heat exchanger; the second-stage regenerator and the intermediate heat exchanger are provided outside the displacer;
The working gas in the space on the high temperature end side of the second stage cold storage material is introduced into the space on the low temperature end side of the second stage cold storage material through the inner intermediate heat exchanger. Cold storage refrigerator. In claim 1 or 2,
The cooling object of the regenerative refrigerator includes a main cooling object that needs to be cooled in a liquid helium temperature range, a second radiant heat shield plate disposed around the main cooling object, and the second radiant heat. A cooling system comprising a liquid nitrogen tank or a first radiant heat shield plate disposed around the shield plate, and the cold generated at the low temperature end of the second stage regenerator is used for cooling the main cooling object. The cold generated at the low temperature end of the first stage regenerator is used for cooling the liquid nitrogen tank or the first radiant heat shield plate, and the cold generated in the intermediate heat exchanger is used for the second radiant heat shield plate. A regenerative refrigerator that is used for cooling. In any one of Claims 1-3,
The regenerative refrigerator is a pulse tube refrigerator. In any one of Claims 1-3,
The regenerative refrigerator is a GM refrigerator or a Stirling refrigerator.

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