JP6284788B2 - Displacer - Google Patents

Description

  The present invention relates to a displacer, and more particularly to a displacer used for a cryogenic refrigerator that generates cold by expanding a high-pressure refrigerant gas supplied from a compression device by Simon.

  There exists a thing of patent document 1 as a displacer type cryogenic refrigerator, for example. This cryogenic refrigerator generates cold by expanding the refrigerant gas in the expansion space while reciprocating the displacer inside the cylinder. A cooling stage is provided adjacent to the expansion space, and the cooling target connected to the cooling stage is cooled by the cooling of the refrigerant gas generated in the expansion space. For example, helium gas is used as the refrigerant gas.

  The displacer contains a cold storage material. When the compressor supplies high-temperature and high-pressure refrigerant gas to the displacer, the cool storage material cools the refrigerant gas. When the displacer exhausts the low-temperature and low-pressure refrigerant gas to the compressor, the regenerator material is cooled by the refrigerant gas. Thus, the cold storage material and the refrigerant gas exchange heat during operation of the cryogenic refrigerator.

JP 2008-224161 A

  In order to increase the amount of heat exchanged between the cold storage material and the refrigerant gas, it is better to lengthen the contact time between the cold storage material and the refrigerant gas. On the other hand, in order to sufficiently expand the refrigerant gas in the expansion space in order to obtain sufficient coldness, it is preferable that the refrigerant gas is exhausted from the displacer containing the cold storage material to the compressor in a short time. The heat exchange efficiency between the refrigerant gas and the cold storage material and the ease of expansion of the refrigerant gas affect the stabilization of the refrigeration performance of the cryogenic refrigerator. For this reason, in order to stabilize the refrigerating performance of the cryogenic refrigerator, it is considered that there is room for adjusting the balance of the flow velocity during intake and exhaust of the refrigerant gas.

  An object of this invention is to provide the technique which stabilizes the refrigerating performance of a cryogenic refrigerator.

  In order to solve the above problems, a displacer for a cryogenic refrigerator according to an aspect of the present invention has a high-temperature end and a low-temperature end, a container for circulating a refrigerant gas, a cold storage material filled in the container, and a container The insertion member inserted in the area | region filled with the cool storage material among these. The insertion member is configured such that the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the container is larger than the flow resistance of the refrigerant gas from the low temperature end to the high temperature end of the container.

  According to the present invention, the refrigeration performance of the cryogenic refrigerator can be stabilized.

It is a figure which shows typically an example of the cryogenic refrigerator which concerns on embodiment. It is a figure which shows an example of the temperature gradient of the 2nd regenerator which concerns on embodiment. 3A to 3B are cross-sectional views schematically showing an example of the shape of the insertion member according to the embodiment. It is a figure which shows typically another example of the shape of the insertion member which concerns on embodiment. It is a figure which shows typically another example of the shape of the insertion member which concerns on embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

  Drawing 1 is a figure showing typically an example of cryogenic refrigerator 1 concerning an embodiment. The cryogenic refrigerator 1 according to the embodiment is a Gifford-McMahon (GM) type cryogenic refrigerator using helium gas as a refrigerant gas, for example. As shown in FIG. 1, the cryogenic refrigerator 1 includes a first displacer 2 and a second displacer 3 connected to the first displacer 2 in the longitudinal direction. The first displacer 2 and the second displacer 3 are connected via, for example, a pin 4, a connector 5, and a pin 6.

  The first cylinder 7 and the second cylinder 8 are integrally formed, and each has a high temperature end and a low temperature end. The low temperature end of the first cylinder 7 and the high temperature end of the second cylinder 8 are connected at the bottom of the first cylinder 7. The second cylinder 8 is formed in a form extending in the same axial direction as the first cylinder 7 and is a cylindrical member having a smaller diameter than the first cylinder 7. The 1st cylinder 7 is a container which accommodates the 1st displacer 2 so that reciprocation is possible in a longitudinal direction. The second cylinder 8 is a container for accommodating the second displacer 3 so as to be reciprocally movable in the longitudinal direction.

  For example, stainless steel is used for the first cylinder 7 and the second cylinder 8 in consideration of strength, thermal conductivity, helium blocking ability, and the like. The outer peripheral portion of the second displacer 3 is a cylinder made of metal such as stainless steel. On the outer peripheral surface of the second displacer 3, a film of an abrasion resistant resin such as a fluororesin may be formed.

  A scotch yoke mechanism (not shown) that reciprocates the first displacer 2 and the second displacer 3 is provided at the high temperature end of the first cylinder 7. The first displacer 2 and the second displacer 3 reciprocate along the first cylinder 7 and the second cylinder 8, respectively. The first displacer 2 and the second displacer 3 each have a high temperature end and a low temperature end.

  The first displacer 2 is a container having a cylindrical outer peripheral surface. For the first displacer 2, for example, a phenol resin with cloth is used from the viewpoint of specific gravity, strength, thermal conductivity, and the like. The inside of the first displacer 2 is filled with a first cold storage material in which, for example, metal (metal mesh) processed into a mesh shape is stacked. The internal volume of the first displacer 2 functions as the first regenerator 9. A rectifier 10 is installed in the upper part of the first regenerator 9, and a rectifier 11 is installed in the lower part. A first opening 13 through which refrigerant gas flows from the room temperature chamber 12 to the first displacer 2 is formed at the high temperature end of the first displacer 2.

  The room temperature chamber 12 is a space formed by the first cylinder 7 and the high temperature end of the first displacer 2. The room temperature chamber 12 changes in volume as the first displacer 2 reciprocates. The room temperature chamber 12 is connected to a common supply / exhaust pipe among the pipes connecting the intake and exhaust systems including the compressor 14, the supply valve 15, and the return valve 16. In addition, a seal 17 is attached between the portion of the first displacer 2 from the high temperature end and the first cylinder 7.

  A second opening 19 is formed at the low temperature end of the first displacer 2 for introducing the refrigerant gas into the first expansion space 18 via the first clearance C1. The first expansion space 18 is a space formed by the first cylinder 7 and the first displacer 2. The volume of the first expansion space 18 changes as the first displacer 2 reciprocates. A first cooling stage 20 that is thermally connected to an object to be cooled (not shown) is disposed at a position corresponding to the first expansion space 18 in the outer periphery of the first cylinder 7. The first cooling stage 20 is cooled by the refrigerant gas passing through the first clearance C1.

The second displacer 3 is a container having a cylindrical outer peripheral surface. The inside of the second displacer 3 is divided into two stages in the axial direction with a rectifier 21 at the upper end, a rectifier 22 at the lower end, and a partition member 23 located in the middle between the upper and lower sides. Of the internal volume of the second displacer 3, the high temperature side region 24 higher than the partition member 23 is filled with a second cold storage material made of a nonmagnetic material such as lead or bismuth. The low temperature side region 25 on the low temperature (lower stage) side of the partition member 23 is filled with a third cold storage material made of a magnetic material such as HoCu ₂ that is different from the high temperature side region 24. Lead, bismuth, HoCu _{2 and the} like are formed in a spherical shape, and a plurality of spherical formations are gathered to form a cold storage material. The partition member 23 prevents the cold storage material in the high temperature side region 24 and the cold storage material in the low temperature side region 25 from mixing. The high temperature side region 24 and the low temperature side region 25, which are internal volumes of the second displacer 3, function as the second regenerator 34. The first expansion space 18 and the high temperature end of the second displacer 3 are communicated with each other through a communication path around the connector 5. Refrigerant gas flows from the first expansion space 18 to the second regenerator 34 through this communication path.

  In the second displacer 3, an insertion member 35 having a refrigerant gas flow path resistance that differs depending on the direction in which the refrigerant gas flows is inserted. More specifically, the insertion member 35 is configured such that the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the second displacer 3 is larger than the flow resistance of the refrigerant gas from the low temperature end to the high temperature end. Has been. Details of the insertion member 35 will be described later.

  A third opening 27 is formed at the low temperature end of the second displacer 3 for allowing the refrigerant gas to flow through the second expansion space 26 via the second clearance C2. The second expansion space 26 is a space formed by the second cylinder 8 and the second displacer 3. The volume of the second expansion space 26 changes as the second displacer 3 reciprocates. The second clearance C <b> 2 is formed by the low temperature end of the second cylinder 8 and the second displacer 3.

  A second cooling stage 28 that is thermally connected to the object to be cooled is disposed at a position corresponding to the second expansion space 26 on the outer periphery of the second cylinder 8. The second cooling stage 28 is cooled by the refrigerant gas passing through the second clearance C2.

  The first displacer 2 and the second displacer 3 may include a lid portion 29 and a lid portion 30 at the low temperature end, respectively. The lid portion 29 and the lid portion 30 have a two-stage cylindrical shape from the viewpoint of joining with the displacer body. The lid portion 29 is fixed to the first displacer 2 by a press-fit pin 31, and the lid portion 30 is fixed to the second displacer 3 by a press-fit pin 32.

  Next, the cooling cycle of the cryogenic refrigerator 1 according to the embodiment will be described. At a certain point in the refrigerant gas supply process, the first displacer 2 and the second displacer 3 are located at the bottom dead center of the first cylinder 7 and the second cylinder 8. When the supply valve 15 is opened at the same time or at a slightly shifted timing, high-pressure helium gas (for example, 2.2 MPa helium gas) is supplied into the first cylinder 7 from the supply / discharge common pipe via the supply valve 15. Then, the air flows into the first regenerator 9 inside the first displacer 2 from the first opening 13 located at the upper part of the first displacer 2. The high-pressure helium gas that has flowed into the first regenerator 9 is cooled by the first regenerator material and enters the first expansion space 18 via the second opening 19 and the first clearance C1 that are located below the first displacer 2. Supplied.

  The high-pressure helium gas supplied to the first expansion space 18 flows into the second regenerator 34 inside the second displacer 3 through the communication passage around the connector 5. The high-pressure helium gas that has flowed into the second regenerator 34 is supplied to the second expansion space 26 through the third opening 27 and the second clearance that are positioned below the second displacer 3 while being cooled by the second regenerator material. Is done.

  In this way, the first expansion space 18 and the second expansion space 26 are filled with the high-pressure helium gas, and the supply valve 15 is closed. At this time, the first displacer 2 and the second displacer 3 are located at the top dead center in the first cylinder 7 and the second cylinder 8. The above is the refrigerant gas supply process.

  When the first displacer 2 and the second displacer 3 open the return valve 16 at the top dead center in the first cylinder 7 and the second cylinder 8 at the same time as the position or slightly shifted, the first expansion space 18 The refrigerant gas in the second expansion space 26 is depressurized and expanded to become low-pressure helium gas (for example, 0.8 MPa helium gas). At this time, cold is generated by the expansion of the refrigerant gas. The helium gas in the first expansion space 18 that has become low temperature due to expansion absorbs the heat of the first cooling stage 20 through the first clearance C1. The helium gas in the second expansion space 26 absorbs the heat of the second cooling stage 28 through the second clearance C2.

  The first displacer 2 and the second displacer 3 move toward the bottom dead center, and the volumes of the first expansion space 18 and the second expansion space 26 decrease. The helium gas in the second expansion space 26 is returned to the first expansion space 18 via the second clearance C2, the third opening 27, the second regenerator 34, and the communication path. Further, the helium gas in the first expansion space 18 is returned to the suction side of the compressor 14 through the second opening 19, the first regenerator 9, and the first opening 13. In that case, the 1st cool storage material, the 2nd cool storage material, and the 3rd cool storage material are cooled with refrigerant gas. That is, the 1st cool storage material, the 2nd cool storage material, and the 3rd cool storage material accumulate cold produced by expansion of refrigerant gas. The above is the exhaust process of the refrigerant gas. The cryogenic refrigerator 1 cools the first cooling stage 20 and the second cooling stage 28 by repeating a cooling cycle in which the process of combining the air supply process and the exhaust process is one cycle.

  Next, the insertion member 35 according to the embodiment will be described in more detail.

  As described above, the cooling cycle in the cryogenic refrigerator 1 includes an operation in which helium gas, which is a refrigerant gas, repeatedly flows in and out to the second regenerator 34 in the second displacer 3. During the operation of the cryogenic refrigerator 1, the regenerator material of the second regenerator 34 has a temperature gradient along the axis of the second regenerator 34.

  FIG. 2 is a diagram illustrating an example of the temperature gradient of the second regenerator 34 according to the embodiment, and the second case where the distance from the high temperature end to the low temperature end of the second regenerator is normalized as 1. FIG. It is a graph which shows the temperature gradient of the cool storage device. As shown in FIG. 2, the temperature gradient of the second regenerator 34 does not decrease linearly from the high temperature end toward the low temperature end. As shown in FIG. 2, the temperature of the second regenerator 34 is about 40K at the high temperature end (normalized distance is 0), and the temperature is about 5K at the low temperature end (normalized distance is 1).

  In the air supply process of the cooling cycle described above, refrigerant gas having a temperature of about 40 K flows from the high temperature end of the second displacer 3. The refrigerant gas flowing into the high temperature end of the second displacer 3 moves toward the low temperature end while being cooled by the cold storage material in the second regenerator 34. For this reason, if the refrigerant gas that has flowed into the high temperature end of the second displacer 3 in the air supply process flows without being sufficiently cooled, the relatively high temperature refrigerant gas will flow into the second expansion space 26, resulting in an extremely low temperature. It becomes a factor which reduces the refrigerating performance of the refrigerator 1.

  On the other hand, in the exhaust process of the cooling cycle described above, the refrigerant gas that is decompressed and expanded in the second expansion space 26 flows from the low temperature end of the second displacer 3, passes through the cold storage material in the second regenerator 34, and reaches the high temperature end. Spill from. For this reason, if the refrigerant gas flowing into the low temperature end of the second displacer 3 cannot pass through the second displacer 3 quickly in the exhaust process, the refrigerant gas cannot be sufficiently expanded in the second expansion space 26.

  By lengthening the time for which the refrigerant gas contacts the cold storage material, heat exchange between the refrigerant gas and the cold storage material can be sufficiently performed. This can be realized by reducing the flow rate of the refrigerant gas flowing in the regenerator material. On the other hand, in order to sufficiently expand the refrigerant gas in the second expansion space 26, the flow rate of the refrigerant gas flowing through the cold storage material may be increased. However, in general, the regenerator material has a mesh shape or a grain shape. These shapes are isotropic in the direction from the high temperature end to the low temperature end of the second displacer 3 and the direction from the low temperature end to the high temperature end. Therefore, the regenerator material accommodated in the second displacer 3 is substantially equal to the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the second displacer 3 and the flow resistance of the refrigerant gas from the low temperature end to the high temperature end. Are equal.

  Therefore, the second displacer 3 according to the embodiment includes an insertion member 35 having anisotropy in flow path resistance in a region filled with the cold storage material.

  3A to 3B are cross-sectional views schematically showing an example of the shape of the insertion member 35 according to the embodiment. FIG. 3A is a view showing a cross section when the insertion member 35 is a so-called Borda's mouthpiece. The base of the boulder has a funnel shape having a first opening 35a and a second opening 35b at both ends, and the area of the first opening 35a is smaller than the area of the second opening 35b. The insertion member 35 is inserted into the region of the second displacer 3 filled with the cold storage material such that the first opening 35a faces the high temperature end and the second opening 35b faces the low temperature end.

  In the insertion member 35, the flow path area of the refrigerant gas continuously decreases from the second opening 35b toward the first opening 35a. For this reason, when the refrigerant gas flows from the low temperature end toward the high temperature end of the second displacer 3, the refrigerant gas flows into the insertion member 35 from the second opening 35b. On the other hand, when the refrigerant gas flows from the high temperature end to the low temperature end of the second displacer 3, the refrigerant gas flows into the insertion member 35 from the first opening 35a. Therefore, the area of the inlet of the insertion member 35 when the refrigerant gas flows from the low temperature end to the high temperature end of the second displacer 3 is the same as that when the refrigerant gas flows from the high temperature end of the second displacer 3 toward the low temperature end. It is larger than the area of the inlet of the insertion member 35. Therefore, in the insertion member 35, the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the second displacer 3 is larger than the flow resistance of the refrigerant gas from the low temperature end to the high temperature end. As a result, the flow rate of the refrigerant gas when going from the high temperature end to the low temperature end of the second displacer 3 in the air supply process of the cooling cycle is smaller than the flow rate when going from the low temperature end to the high temperature end in the exhaust process. Therefore, the refrigerant gas is easily cooled by the cold storage material in the air supply process, and the refrigerant gas is easily expanded in the second expansion space 26 in the exhaust process.

  As shown in FIG. 3A, the cross section of the base of the boulder is a curve. For this reason, when it goes to the 1st opening part 35a from the 2nd opening part 35b, the flow-path area of the insertion member 35 changes nonlinearly. More specifically, the change rate of the flow channel area at both ends of the insertion member 35, that is, in the vicinity of the first opening 35 a and the second opening 35 b is smaller than the change rate of the central portion of the insertion member 35.

  In addition, the insertion member 35 may have a linear taper shape in which the flow path area changes linearly. FIG. 3B is a diagram showing a cross section when the insertion member 35 has a linear taper. Similarly to the insertion member 35 shown in FIG. 3A, the insertion member 35 shown in FIG. 3B also includes a first opening 35a and a second opening 35b at both ends. The area of the first opening 35a of the insertion member 35 is smaller than the area of the second opening 35b. The insertion member 35 is inserted into the region of the second displacer 3 filled with the cold storage material such that the first opening 35a faces the high temperature end and the second opening 35b faces the low temperature end. Thereby, also in the insertion member 35 shown in FIG. 3B, the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the second displacer 3 is higher than the flow resistance of the refrigerant gas from the low temperature end to the high temperature end. growing.

  FIGS. 4A to 4B are diagrams schematically illustrating another example of the shape of the insertion member 35 according to the embodiment. The insertion member 35 is a disc-shaped punching plate having a plurality of refrigerant gas flow paths. 4A is a top view of the insertion member 35, and FIG. 4B is a cross-sectional view taken along line A-A 'in FIG. 4A.

  The insertion member 35 shown in FIG. 4 is inserted in the area | region with which the cool storage material of the 2nd displacer 3 is filled. The insertion member 35 is made of, for example, a metal such as stainless steel, and a plurality of refrigerant gas flow paths are formed by punching. Each of the refrigerant gas flow paths includes a first opening 35 a directed to the high temperature end side of the second displacer 3 and a second opening 35 b directed to the low temperature end side.

  As shown in FIG. 4B, the area of the first opening 35a is configured to be smaller than the area of the second opening 35b in each refrigerant gas flow path. Thereby, when the refrigerant gas flows from the low temperature end of the second displacer 3 toward the high temperature end, the area of the inlet for passing through the insertion member 35 is larger than the area when the refrigerant gas flows from the high temperature end toward the low temperature end. growing. Therefore, in the insertion member 35, the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the second displacer 3 is larger than the flow resistance of the refrigerant gas from the low temperature end to the high temperature end. As a result, the flow rate of the refrigerant gas when going from the high temperature end to the low temperature end of the second displacer 3 in the air supply process of the cooling cycle is smaller than the flow rate when going from the low temperature end to the high temperature end in the exhaust process. Therefore, the refrigerant gas is easily cooled by the cold storage material in the air supply process, and the refrigerant gas is easily expanded in the second expansion space 26 in the exhaust process.

  Fig.5 (a)-(b) is a figure which shows typically another example of the shape of the insertion member 35 which concerns on embodiment. The insertion member 35 is a circular plate-like member having a plurality of refrigerant gas flow paths. FIG. 5A is a top view of the insertion member 35, and FIG. 5B is a cross-sectional view taken along line A-A 'in FIG.

  Similarly to the insertion member 35 shown in FIG. 4, the insertion member 35 shown in FIG. 5 is also inserted into the region where the cold storage material of the second displacer 3 is filled. The insertion member 35 is, for example, a resin such as phenol with cloth, and one surface is embossed. For this reason, the insertion member 35 shown in FIG. 5 includes a plurality of cone-shaped convex portions on the surface on which embossing is performed. Here, the apex of the cone in each cone-shaped convex portion and the other surface of the insertion member 35 penetrate, and a flow path for the refrigerant gas is formed. Each of the flow paths includes a first opening 35a on the apex side of the cone and a second opening 35b on the other side, and the area of the first opening 35a is the area of the second opening 35b. Is smaller than The insertion member 35 is fitted into the second displacer 3 so that the first opening 35a faces the high temperature end side of the second displacer 3 and the second opening 35b faces the low temperature end side.

  Thereby, when the refrigerant gas flows from the low temperature end of the second displacer 3 toward the high temperature end, the area of the inlet for passing through the insertion member 35 is larger than the area when the refrigerant gas flows from the high temperature end toward the low temperature end. growing. Therefore, in the insertion member 35, the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the second displacer 3 is larger than the flow resistance of the refrigerant gas from the low temperature end to the high temperature end. As a result, the flow rate of the refrigerant gas when going from the high temperature end to the low temperature end of the second displacer 3 in the air supply process of the cooling cycle is smaller than the flow rate when going from the low temperature end to the high temperature end in the exhaust process. Therefore, the refrigerant gas is easily cooled by the cold storage material in the air supply process, and the refrigerant gas is easily expanded in the second expansion space 26 in the exhaust process.

  Here, in the insertion member 35 shown in FIGS. 4 and 5, a plurality of refrigerant gas flow paths are distributed on the surface of the insertion member 35. For this reason, compared with the insertion member 35 shown in FIG. 3, the refrigerant gas can pass through the insertion member 35 in a wide range in the second displacer 3. Therefore, the area where the refrigerant gas contacts the cold storage material after passing through the insertion member 35 shown in FIGS. 4 and 5 is also wider than that of the insertion member 35 shown in FIG. Therefore, the insertion member 35 shown in FIGS. 4 and 5 can improve the heat exchange efficiency between the refrigerant gas that has passed through the insertion member 35 and the cold storage material, as compared with the insertion member 35 shown in FIG. 3.

  On the other hand, the insertion member 35 shown in FIGS. 4 and 5 is thicker than the insertion member 35 shown in FIG. Therefore, when inserted into the second displacer 3, the insertion member 35 shown in FIG. 3 has a smaller dead volume than the insertion member 35 shown in FIGS. Therefore, when inserted into the second displacer 3, the insertion member 35 shown in FIG. 3 can be filled with a larger amount of cold storage material than the insertion member 35 shown in FIGS.

  As described above, the second displacer 3 according to the embodiment includes the insertion member 35 shown in FIG. 3, FIG. 4, or FIG. 5, so that the refrigerant gas traveling from the high temperature end to the low temperature end of the second displacer 3. Is greater than the flow path resistance of the refrigerant gas from the low temperature end toward the high temperature end. Thereby, the time for which the refrigerant gas comes into contact with the cold storage material in the air supply process is lengthened, and the refrigerant gas is sufficiently cooled by the cold storage material. In the exhaust process, the refrigerant gas is quickly discharged from the second displacer 3, so that the refrigerant gas easily expands in the second expansion space 26. As a result, the refrigeration performance of the cryogenic refrigerator 1 can be stabilized.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions are made to the above-described embodiments without departing from the scope of the present invention. be able to.

Although in the above-mentioned cryogenic refrigerator showing a case number is two-stage, the number of stages may be single-stage, it may be appropriately selected in three or more stages. Moreover, although the cryogenic refrigerator demonstrated the example of the displacer-type GM refrigerator with embodiment, it is not restricted to this. The present invention can be applied to any refrigerating machine in which refrigerant gas reciprocates inside the regenerator. For example, the present invention can also be applied to a Stirling refrigerating machine, a Solvay refrigerating machine, and the like.

  The case where the insertion member 35 is inserted into the cold storage material accommodated in the second displacer 3 has been mainly described above. The insertion member 35 may be inserted into the first displacer 2 instead of or in addition to the second displacer 3. By inserting the insertion member 35 into the first displacer 2, the flow rate of the refrigerant gas when going from the high temperature end to the low temperature end of the first displacer 2 in the air supply process of the cooling cycle is changed from the low temperature end to the high temperature end in the exhaust process. It becomes smaller than the flow velocity when heading. Therefore, the refrigerant gas is easily cooled by the cool storage material in the first displacer 2 in the air supply process, and the refrigerant gas is easily expanded in the first expansion space 18 in the exhaust process. Thereby, the refrigerating performance of the cryogenic refrigerator 1 can be further stabilized.

  Here, as described above, the regenerator material accommodated in the first displacer 2 is a laminate of metals processed in a mesh shape. Therefore, when inserting the insertion member 35 shown in FIG. 3 into the 1st displacer 2, you may insert between the meshes which are cold storage materials.

  On the other hand, the cool storage material accommodated in the second displacer 3 is a metal processed into a spherical shape having a diameter of about 0.5 mm, for example. For this reason, when the insertion member 35 shown in FIG. 3 is inserted into the cold storage material accommodated in the second displacer 3, the insertion member 35 is held by the cold storage material and its shape is also maintained. Therefore, the insertion member 35 shown in FIG. 3 is preferably inserted into the second displacer 3. When the cryogenic refrigerator 1 is a multi-stage refrigerator having three or more displacers, the insertion member 35 shown in FIG. 3 is preferably inserted into a displacer provided in the final stage.

  1 Cryogenic refrigerator, C1 first clearance, 2 first displacer, C2 second clearance, 3 second displacer, 4 pin, 5 connector, 6 pin, 7 first cylinder, 8 second cylinder, 9 first regenerator 10, 11 Rectifier, 12 Room temperature chamber, 13 First opening, 14 Compressor, 15 Supply valve, 16 Return valve, 17 Seal, 18 First expansion space, 19 Second opening, 20 First cooling stage, 21, 22 23 rectifiers, 23 materials, 24 high temperature side region, 25 low temperature side region, 26 second expansion space, 27 third opening, 28 second cooling stage, 29, 30 lid, 31, 32 press-fit pin, 34 second regenerator, 35 insert member, 35a first opening, 35b second opening.

Claims (4)

A cryogenic refrigerator displacer,
A container having a high temperature end and a low temperature end for circulating refrigerant gas;
A cold storage material filled in the container;
An insertion member inserted in the region filled with the cold storage material of the container,
The insertion member is configured such that the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the container is larger than the flow resistance of the refrigerant gas from the low temperature end to the high temperature end of the container ,
Said insert member, the displacer, characterized in die der Rukoto the Borda. The insertion member is
Comprising a refrigerant gas flow path having a first opening directed toward the high temperature end of the container and a second opening directed toward the low temperature end of the container;
The displacer according to claim 1, wherein the flow path is configured such that an area of the first opening is smaller than an area of the second opening. The cryogenic refrigerator is a multi-stage refrigerator having a plurality of displacers,
The displacer according to claim 1 or 2 , wherein the displacer is a displacer provided in a final stage of the cryogenic refrigerator. A cryogenic refrigerator displacer,
A container having a high temperature end and a low temperature end for circulating refrigerant gas;
A cold storage material filled in the container;
An insertion member inserted in the region filled with the cold storage material of the container,
The insertion member is configured such that the flow resistance of the refrigerant gas from the high temperature end to the low temperature end of the container is larger than the flow resistance of the refrigerant gas from the low temperature end to the high temperature end of the container,
The insertion member is a plate having a plurality of cone-shaped projections on the surface on the high temperature end side of the container, and the apex of the cone in each cone-shaped projection and the surface on the low temperature end side of the insertion member A refrigerant gas flow path is formed between
The channel, the area of the opening at the apex of the cones, features and to Lud Isupuresa is smaller than the area of the opening in the plane of the cold end side of the insertion member.

Images