JP5606744B2 - Pulse tube refrigerator - Google Patents

Description

  The present invention relates to a pulse tube refrigerator.

  2. Description of the Related Art A pulse tube refrigerator is used for cooling an apparatus that requires a cryogenic environment, such as a nuclear magnetic resonance diagnostic apparatus (MRI).

  In a pulse tube refrigerator, refrigerant gas (for example, helium gas), which is a working fluid compressed by a compressor, flows into the cold storage tube and the pulse tube, and the refrigerant gas is discharged from the pulse tube and the cold storage tube. By repeating the operation collected in the above, cold is formed at the low temperature ends of the regenerator tube and the pulse tube.

  The regenerator tube of the pulse tube refrigerator is composed of a cylindrical member (cylinder) having a regenerator material inside, and the pulse tube is composed of a hollow tubular member (cylinder). The low temperature ends of both cylinders communicate with each other through a communication path, and a cooling stage to which the object to be cooled is connected is installed at this position.

  Generally, a heat exchanger is installed on the low temperature end side of the pulse tube, and the inside of the heat exchanger is filled with a copper wire mesh (Patent Document 1).

Japanese Patent Laid-Open No. 2002-235932

  In the conventional pulse tube refrigerator, the heat exchanger portion on the low temperature end side of the pulse tube is filled with a copper wire mesh. The metal mesh is used in order to prevent a large difference in the velocity of the refrigerant gas when the refrigerant gas flows into the pulse tube from the cold storage tube, that is, to enhance the rectifying effect of the refrigerant gas.

  However, with a copper wire mesh, there is a problem that it is difficult to manufacture a large mesh (fine mesh) due to processing technology and cost constraints. Therefore, in usual cases, the mesh of the copper wire mesh is less than # 100 (for example, # 80).

  However, such a mesh metal mesh may not provide a sufficient rectifying effect for the refrigerant gas. In addition, when the rectifying effect is insufficient, the flux (gas piston) of the gas flowing in the pulse tube may be disturbed, resulting in a problem that the refrigeration performance of the pulse tube refrigerator is deteriorated.

  This invention is made | formed in view of such a background, and it aims at providing the pulse tube refrigerator which has a favorable rectification | straightening function between a cool storage tube and a pulse tube compared with the past in this invention. To do.

In the present invention, a pulse tube refrigerator in which the low temperature end of the pulse tube and the low temperature end of the regenerator tube are communicated by a communication path,
On the low temperature end side of the pulse tube of the communication path, a heat exchanger is installed,
The heat exchanger has a laminate composed of at least two layers of a first wire mesh and a second wire mesh,
The first wire mesh is made of a metal different from copper or a copper alloy, and the second wire mesh is made of copper or a copper alloy,
The interface between the two wire meshes is diffusion bonded,
The mesh of the first wire mesh is smaller than the mesh of the second wire mesh,
There is provided a pulse tube refrigerator, wherein the heat exchanger is installed in the communication path so that the first wire mesh side of the laminated body is furthest away from the low temperature end of the regenerator. The

In the pulse tube refrigerator according to the present invention, the laminate further includes a third wire mesh on the opposite side of the second wire mesh from the first wire mesh, A fourth wire mesh is laminated on the side opposite to the second wire mesh,
The third wire mesh is made of a metal different from copper or a copper alloy, and the fourth wire mesh is made of copper or a copper alloy,
The interface between the metal meshes may be diffusion bonded.

Moreover, in the pulse tube refrigerator according to the present invention, the laminated body is composed of an alternating repeating structure of a wire mesh made of a metal different from copper or copper alloy and a wire mesh made of copper or copper alloy throughout. ,
The interface between the metal meshes may be diffusion bonded.

Further, in the pulse tube refrigerator according to the present invention, the laminated body has a portion in which a plurality of copper or copper alloy wire meshes are directly laminated on the opposite side of the second wire mesh to the first wire mesh. Have
The size of the mesh of the plurality of copper or copper alloy wire meshes in the portion may increase continuously or stepwise along the stacking direction of the laminate from the first wire mesh side. .

  Moreover, in the pulse tube refrigerator according to the present invention, the mesh size of the wire mesh made of a metal different from the copper or copper alloy may be in the range of 0.02 mm to 0.58 mm.

  In the pulse tube refrigerator according to the present invention, the size of the mesh of the copper or copper alloy wire mesh may be in the range of 0.05 mm to 1.14 mm.

  In the pulse tube refrigerator according to the present invention, at least one of the metal meshes made of a metal different from the copper or the copper alloy may be made of stainless steel or nickel.

  Moreover, in the pulse tube refrigerator according to the present invention, the wire mesh made of a metal different from each copper or copper alloy may be made of the same material.

  Moreover, in the pulse tube refrigerator according to the present invention, the side surface of the laminate may be diffusion bonded to a wall constituting the communication path.

Alternatively, the laminate is housed in a case made of copper or copper alloy,
The side surface of the laminate may be diffusion bonded to the inner wall of the housing.

  According to the present invention, it is possible to provide a pulse tube refrigerator having a better rectification function between a regenerator tube and a pulse tube as compared with the prior art.

It is the figure which showed roughly an example of the pulse tube refrigerator by this invention. It is a schematic exploded block diagram of an example of the laminated body 150 for heat exchangers. It is a schematic exploded block diagram of an example of another laminated body 150A for heat exchangers. It is typical sectional drawing near the groove | channel 189 of the cooling stage 180 in which the heat exchanger 149b-2 is arrange | positioned. It is typical sectional drawing of the groove | channel 189 vicinity of the cooling stage 180 in which another heat exchanger 149b-3 is arrange | positioned.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 schematically shows an example of a pulse tube refrigerator according to the present invention.

  As shown in FIG. 1, the pulse tube refrigerator 100 according to the present invention includes a compressor 110, a regenerator tube 120, a pulse tube 140, a cooling stage 180, and a buffer tank 190. The regenerative tube 120 has a high temperature end 125a and a low temperature end 125b, and the pulse tube 140 has a high temperature end 145a and a low temperature end 145b.

  An exhaust valve 110 a and an intake valve 110 b are connected to the compressor 110. The compressor 110 is connected to the high temperature end 125 a of the regenerator tube 120 via the gas flow path 112.

  The regenerator tube 120 is configured by a hollow cylinder 121, and the regenerator material 122 is filled therein. The cylinder 121 is made of, for example, stainless steel.

  The pulse tube 140 is constituted by a hollow cylinder 141 made of stainless steel, for example. A heat exchanger 149 a is provided on the high temperature end 145 a side of the pulse tube 140, and a heat exchanger 149 b is provided on the low temperature end 145 b side of the pulse tube 140.

  The low temperature end 125b of the regenerator tube 120 and the low temperature end 145b of the pulse tube 140 are in contact with and fixed to a cooling stage 180 made of copper. Further, the low temperature end 125 b of the regenerator tube 120 and the low temperature end 145 b of the pulse tube 140 are communicated with each other through a communication path 182 provided in the cooling stage 180. The cooling stage 180 is thermally connected to an object to be cooled (not shown), and the object to be cooled is cooled.

  The buffer tank 190 is connected to the high temperature end 145 a of the pulse tube 140 through the gas flow path 192 and the orifice 194.

  The regenerator tube 120 and the pulse tube 140 have their high temperature ends 125a and 145a connected to the flange 115, and are fixed thereby.

  Next, operation | movement of the pulse tube refrigerator comprised in this way is demonstrated easily.

  First, in a state where the exhaust valve 110a is opened and the intake valve 110b is closed, high-pressure refrigerant gas is supplied from the gas compressor 110 to the regenerator pipe 120 via the exhaust valve 110a and the gas flow path 112. The refrigerant gas that has flowed into the cold storage tube 120 passes through the communication path 182 from the low temperature end 125b of the cold storage tube 120 while being cooled by the cold storage material 122 to lower the temperature. The refrigerant gas is further cooled by the heat exchanger 149 b provided at the low temperature end 145 b of the pulse tube 140 and flows into the pulse tube 140.

  At this time, the low-pressure refrigerant gas existing in advance inside the pulse tube 140 is compressed by the high-pressure refrigerant gas that has flowed in. Thereby, the pressure of the refrigerant gas in the pulse tube 140 becomes higher than the pressure in the buffer tank 190, and the refrigerant gas flows into the buffer tank 190 through the orifice 194 and the gas flow path 192.

  Next, when the exhaust valve 110a is closed and the intake valve 110b is opened, the refrigerant gas in the pulse tube 140 passes through the low temperature end 145b and flows into the low temperature end 125b of the regenerator tube 120. Further, the refrigerant gas passes through the regenerator tube 120 while cooling the regenerator material 122, and is collected by the compressor 110 from the high temperature end 125a through the gas flow path 112 and the intake valve 110b.

  Here, the pulse tube 140 is connected to the buffer tank 190 via the orifice 194. For this reason, the phase of the pressure fluctuation of the refrigerant gas and the phase of the volume change of the refrigerant gas change with a constant phase difference. Due to this phase difference, cold occurs due to expansion of the refrigerant gas at the low temperature end 145 b of the pulse tube 140. The pulse tube refrigerator 100 can cool the object to be cooled connected to the cooling stage 180 by repeating the above operation.

  In the pulse tube refrigerator 100 as described above, the movement of the refrigerant gas that periodically flows up and down in the pulse tube 140 while maintaining a certain pressure is often referred to as a “gas piston”.

  By the way, in the conventional pulse tube refrigerator, the heat exchanger installed on the low temperature end side of the pulse tube is made of copper or a copper alloy (hereinafter, both are simply referred to as “copper (made)”). Wire mesh is filled and used. The reason for using such a wire mesh is to prevent a large difference in the speed of the refrigerant gas when the refrigerant gas flows into the pulse tube from the regenerator, that is, to obtain a rectifying effect of the refrigerant gas. .

  However, with a copper wire mesh, there is a problem that it is difficult to manufacture a large mesh (fine mesh) due to processing technology and cost constraints. Therefore, in usual cases, the mesh of the copper wire mesh is less than # 100 (for example, # 80). This is equivalent to about 0.134 mm or more (for example, about 0.138 mm to about 0.218 mm) in terms of the mesh of the wire mesh.

  In this application, “mesh” means the number of meshes between 1 inch (25.4 mm), and “mesh” means the distance between adjacent wire portions of the wire mesh (the length of the gap). Means.

  However, such a mesh or mesh wire mesh may not provide a sufficient rectifying effect for the refrigerant gas. In addition, when the rectifying effect is insufficient, the above-described gas piston is disturbed, and as a result, there may be a problem that the refrigeration performance of the pulse tube refrigerator is deteriorated.

  On the other hand, in the pulse tube refrigerator according to the present invention, the heat exchanger 149b on the low temperature end 145b side of the pulse tube 140 is a wire mesh (hereinafter referred to as “non-copper-made” made of a metal different from copper or copper alloy). And a laminated body 150 having a copper wire mesh. The non-copper wire mesh has a larger mesh than that of the copper wire mesh, and the laminated body 150 has a non-copper wire mesh at a position farthest from the low temperature end 125b of the regenerator tube 120. And installed in the communication path 182. For this reason, in this invention, the rectification | straightening effect of refrigerant gas can be heightened compared with the conventional heat exchanger comprised by laminating | stacking only a copper metal mesh.

  Hereinafter, the features of the present invention will be described in more detail.

  In FIG. 2, the schematic block diagram of an example of the laminated body 150 for the heat exchanger 149b used for this invention is shown.

  In the laminated body 150, the first wire mesh 152A, the second wire mesh 152B, the third wire mesh 152C, the fourth wire mesh 152D, and the nth wire mesh 152N are laminated in this order to form an assembly 151. Thereafter, this assembly 151 is formed by diffusion bonding.

  In the example of FIG. 2, the first wire mesh 152A is made of a non-copper metal or alloy. The second metal mesh 152B to the nth metal mesh 152N are made of copper. For example, the first wire mesh 152A may be stainless steel (SUS304, 316, etc.) or nickel. Stainless steel and nickel are more rigid than copper. Therefore, when the first wire net 152A is made of stainless steel or nickel, the rigidity of the finally obtained laminate 150 can be increased, and the laminate 150 is deformed by the pressure of the refrigerant gas during use. Less likely.

  The first wire mesh 152A has a larger mesh, that is, a smaller mesh than other wire meshes. For example, the mesh of the first wire net 152A is in the range of # 30 to # 500, and preferably in the range of # 60 to # 400. This corresponds to about 0.577 mm to about 0.026 mm and about 0.253 mm to about 0.034 mm, respectively, in terms of mesh. On the other hand, the meshes of the second wire mesh 152B to the nth wire mesh 152N are in the range of # 16 to # 300, and preferably in the range of # 60 to # 150. This corresponds to about 1.14 mm to about 0.05 mm and about 0.303 mm to about 0.104 mm, respectively, in terms of mesh.

  The second metal mesh 152B to the n-th metal mesh 152N may be the same or different in mesh or mesh. When the meshes or meshes of the respective metal meshes 152B to 152N are different, the meshes may be increased in order from the second metal mesh 152B to the nth metal mesh 15N in a continuous or stepwise manner (for example, in a step shape). In this case, when the refrigerant gas flows from the regenerator tube 120 to the pulse tube 140, a large fluctuation in the flow rate of the refrigerant gas is less likely to occur, and a more significant rectification effect is obtained.

  The total number of wire meshes varies depending on the thickness of each wire mesh, but may be in the range of 2 to 200 (for example, 100).

  As described above, the laminated body 150 is formed by stacking the metal meshes to form the assembly 151 and then subjecting the assembly 151 to diffusion bonding. “Diffusion bonding treatment” is a general term for a method in which atomic interdiffusion occurs at the interface between metal meshes by heating, and thereby interface bonding is performed. Usually, the diffusion bonding process is performed in a range of 800 ° C. to 1080 ° C. (eg, 1000 ° C.).

  Due to the diffusion bonding process, the interfaces between the metal meshes are brought into close contact and bonded. Therefore, the thermal contact property at each interface is increased and the thermal resistance is decreased.

  When the laminate 150 is used, the side of the first wire mesh 152A is located on the side far from the low temperature end 125b of the regenerator tube 120 (in the example of FIG. 1, it is on the upper side). It is installed in 182. Thereby, a high rectification effect is obtained for the refrigerant gas reciprocating between the regenerator tube 120 and the pulse tube 140. This also makes it possible to provide the pulse tube refrigerator 100 with improved cooling performance.

  In FIG. 3, the schematic block diagram of an example of another laminated body 150A used for the heat exchanger 149b of this invention is shown.

  In the example of this figure, the laminated body 150A includes a first wire mesh 153A, a second wire mesh 153B, a third wire mesh 153C, a fourth wire mesh 153D, a fifth wire mesh 153E, a sixth wire mesh 153F ... The n-1 wire mesh 153N-1 and the nth wire mesh 153N are stacked in this order, and the obtained assembly 151A is diffusion bonded.

  The second wire mesh 153B, the fourth wire mesh 153D, and the sixth wire mesh 153F to the n-th wire mesh 153N are made of copper. In contrast, the first wire mesh 153A, the third wire mesh 153C, and the fifth wire mesh 153E are made of a non-copper metal or alloy. For example, the first wire mesh 153A, the third wire mesh 153C, and the fifth wire mesh 153E are made of stainless steel (SUS304, 316, etc.) or nickel. The first wire mesh 153A, the third wire mesh 153C, and the fifth wire mesh 153E may be made of the same material or different materials.

  In the configuration of this figure, the cycle C in which the non-copper wire mesh and the copper wire mesh are alternately laminated is repeated three times.

  The first wire mesh 153A, the third wire mesh 153C, and the fifth wire mesh 153E have larger meshes (that is, smaller meshes) than the other wire meshes. For example, the meshes of the first wire mesh 153A, the third wire mesh 153C, and the fifth wire mesh 153E are in the range of # 30 to # 500 (in terms of mesh, about 0.577 mm to about 0.026 mm). A range of 60 to # 400 (in terms of mesh, about 0.253 mm to about 0.034 mm) is preferable. On the other hand, the meshes of the remaining copper metal meshes 153B, 153D, and 153F to 153N are in the range of # 16 to # 300 (about 1.14 mm to about 0.05 mm in terms of mesh), and # 60 to # 150 (mesh) It is preferably in the range of about 0.303 mm to about 0.104 mm in terms of conversion. The copper wire mesh may have the same or different mesh size. When the sizes of the meshes of the copper metal meshes 153B to 153N are different, the meshes may increase continuously or stepwise from the second metal mesh 153B to the nth metal mesh 153N.

  The total number of wire meshes may be in the range of 2 to 200 (for example, 100), depending on the thickness of each wire mesh.

  When the laminate 150A shown in FIG. 3 is used, the side of the first wire mesh 153A is located on the side far from the low temperature end 125b of the regenerator 120 (in the example of FIG. ) And installed in the communication path 182.

  In the example of FIG. 3, the laminated body 150 </ b> A including three non-copper wire meshes and having a cycle number C of 3 has been described. However, in the laminate 150 </ b> A, the number of non-copper wire meshes and the cycle number C are Not particularly limited. The number of non-copper wire meshes may be two, four, six or more, for example. Further, the number of repetitions C may be two times, four times, or six times or more. For example, the alternate arrangement of the non-copper and copper wire meshes may be repeated from the first wire mesh to the nth wire mesh (that is, over the entire laminated body 150A).

  Next, another heat exchanger 149b-2 will be described with reference to FIG. FIG. 4 schematically shows a cross section near the groove 189 of the cooling stage 180 to which the low temperature end 145b of the pulse tube 140 is connected. This figure shows a schematic cross section of an example of the heat exchanger 149b-2 used in the present invention.

  As shown in FIG. 4, the heat exchanger 149b-2 has a laminated body 150A installed in the groove 189, and this laminated body 150A has the same structure as the laminated body 150A shown in FIG. Have. However, the heat exchanger 149b-2 has a feature that the side surface of the multilayer body 150A is diffusion bonded to the inner wall 184 of the groove 189.

  In such a heat exchanger 149b-2, compared with the case where the laminated body 150A is filled in the groove 189 later, the thermal contact property between the laminated body 150A and the cooling stage 180 can be improved. The thermal resistance of can be significantly suppressed.

  The laminated body 150A can be easily formed by filling the groove 151A of the cooling stage 180 with the assembly 151A of the metal meshes 153A to 153N and then performing diffusion bonding processing together with the cooling stage 180. That is, by diffusion bonding, the metal meshes are diffusion bonded together, and at the same time, the side surface of the laminate 150A is diffusion bonded to the inner wall 184 of the groove 189.

  In the example of FIG. 4, the laminated body 150A has the same configuration as the laminated body 150A shown in FIG. 3, that is, has three non-copper wire meshes 153A, 153C, and 153E. However, this is an example, and it will be apparent that the configuration of the laminate is not limited to this. The configuration of the stacked body may be another configuration such as the stacked body 150 of FIG.

  In the example of FIG. 4, the side surface of the stacked body 150 </ b> A is diffusion bonded to the inner wall 184 of the structure 189 of the cooling stage 180. However, the embodiment of the present invention is not limited to this. For example, the side surface of the laminated body 150A may be diffusion bonded to the inner wall on the low temperature end 145b side of the cylinder 141 that constitutes the pulse tube 140.

  Next, still another heat exchanger 149b-3 will be described with reference to FIG. FIG. 5 schematically shows a cross section near the groove 189 of the cooling stage 180 to which the low temperature end 145b of the pulse tube 140 is connected. This figure shows a schematic cross section of an example of the heat exchanger 149b-3 used in the present invention.

  As shown in FIG. 5, the heat exchanger 149 b-3 has a stacked body 150 </ b> A installed in the groove 189. This laminated body 150A has the same structure as the laminated body 150A shown in FIG. However, the heat exchanger 149b-3 further has a feature of including a housing 159 that accommodates the stacked body 150A.

  The housing 159 is made of copper or a copper alloy. The housing 159 has an upper surface and a lower surface that are open, and has a side surface dimension (in this case, an outer diameter) that substantially matches the inner diameter of the groove 189. The side surface of the laminated body 150 </ b> A is diffusion bonded to the inner wall of the side surface of the housing 159.

  Such a heat exchanger 149b-3 can be formed by filling the casing 151A with the assembly 151A of the wire meshes 153A to 153N and then performing diffusion bonding processing on the entire casing. Thereafter, the housing 159 is installed in the groove 189 of the cooling stage 180. Thereafter, the housing 159 may be brazed to the inner wall 184 of the groove 189 of the cooling stage 180.

  Even in such a configuration, the thermal contact between the laminated body 150A (more precisely, the housing 159) and the cooling stage 180 can be improved as compared with the case where the laminated body is simply filled into the groove 189 later. And the thermal resistance between the two can be significantly suppressed.

  The example of the embodiment according to the present invention has been described above with reference to the drawings. However, it will be apparent to those skilled in the art that the present invention is not limited to the above-described configuration. For example, in the above-described example, the pulse tube refrigerator 100 is a single stage type. However, the present invention can also be applied to a two-stage or three-stage multi-stage pulse tube refrigerator.

  Next, examples of the present invention will be described.

  Actually, a pulse tube refrigerator having the heat exchanger 149b-2 as shown in FIG. 4 formed in the groove of the cooling stage was operated under normal conditions, and the temperature of the cooling stage was measured. As the laminate, the laminate 150 having the configuration shown in FIG. 2 was used. As the uppermost wire mesh 152A, a wire mesh made of SUS304 having a mesh of # 250 was used. Further, a copper wire mesh having a mesh of # 80 was used for the second and subsequent wire meshes.

  As a result of the measurement, the temperature of the cooling stage was about 36.4K (Kelvin). On the other hand, in a pulse tube refrigerator equipped with a conventional heat exchanger configured by filling the groove of the cooling stage with a # 80 copper laminate, the temperature of the cooling stage was measured. Was about 40.2 K (Kelvin).

  From this result, it was confirmed that the cooling capacity of the pulse tube refrigerator according to the present invention is improved as compared with the conventional case.

  The present invention can be applied to a single-stage or multi-stage pulse tube refrigerator applied to a low-temperature system such as a nuclear magnetic resonance diagnostic apparatus, a superconducting magnet apparatus, or a cryopump.

DESCRIPTION OF SYMBOLS 100 Pulse tube refrigerator 110 Compressor 110a Exhaust valve 110b Intake valve 112 Gas flow path 115 Flange 120 Regenerator tube 121 Cylinder 122 Regenerator material 125a High temperature end of regenerator tube 125b Cold end of regenerator tube 140 Pulse tube 141 Cylinder 145a High temperature of pulse tube End 145b Cold end of pulse tube 149a Heat exchanger 149b, 149b-2, 149b-3 Heat exchanger according to the present invention 150 Laminate 150A Another laminate 151, 151A Assembly 152A, 153A First wire mesh 152B, 153B First Second wire mesh 152C, 153C Third wire mesh 159 Housing 180 Cooling stage 182 Communication path 184 Inner wall 189 Groove 190 Buffer tank 192 Gas flow path 194 Orifice.

Claims (9)

A pulse tube refrigerator in which the low temperature end of the pulse tube and the low temperature end of the regenerator tube are communicated by a communication path,
On the low temperature end side of the pulse tube of the communication path, a heat exchanger is installed,
The heat exchanger has a laminate composed of at least two layers of a first wire mesh and a second wire mesh,
The first wire mesh is made of a metal different from copper or a copper alloy, and the second wire mesh is made of copper or a copper alloy,
The interface between the first wire mesh and the second wire mesh is diffusion bonded,
The mesh of the first wire mesh is smaller than the mesh of the second wire mesh,
The first wire mesh is made of stainless steel or nickel, and the heat exchanger is arranged such that the side of the first wire mesh of the laminate having the smaller mesh is farthest from the cold end of the regenerator tube, A pulse tube refrigerator, wherein the pulse tube refrigerator is installed in the communication path, thereby increasing the rigidity of the laminate . The laminate further includes a third wire mesh on a side of the second wire mesh opposite to the first wire mesh, and the third wire mesh is opposite to the second wire mesh. On the side, a fourth wire mesh is laminated,
The third wire mesh is made of a metal different from copper or a copper alloy, and the fourth wire mesh is made of copper or a copper alloy,
The pulse tube refrigerator according to claim 1, wherein an interface between the metal meshes is diffusion bonded. The laminate is composed of an alternating repeating structure of a wire mesh made of a metal different from copper or a copper alloy and a wire mesh made of copper or a copper alloy throughout,
The pulse tube refrigerator according to claim 1 or 2, wherein an interface between the metal meshes is diffusion bonded. The laminate has a portion in which a plurality of copper or copper alloy wire meshes are directly laminated on the opposite side of the second wire mesh to the first wire mesh,
The size of the mesh of the plurality of copper or copper alloy wire meshes in the portion increases continuously or stepwise along the stacking direction of the laminate from the side of the first wire mesh. The pulse tube refrigerator according to claim 1 or 2. The pulse tube refrigerator according to any one of claims 1 to 4, wherein a mesh size of the first wire mesh is in a range of 0.02 mm to 0.58 mm.   The pulse tube refrigerator according to any one of claims 1 to 5, wherein a mesh size of the copper or copper alloy wire mesh is in a range of 0.05 mm to 1.14 mm. Each copper or wire mesh made of a different metal than the copper alloy, the pulse tube refrigerator according to any one of claims 1 to 6, characterized in that it is made of the same material. The pulse tube refrigerator according to any one of claims 1 to 7 , wherein a side surface of the laminate is diffusion-bonded to a wall constituting the communication path. The laminate is housed in a case made of copper or copper alloy,
The pulse tube refrigerator according to any one of claims 1 to 7 , wherein a side surface of the laminate is diffusion bonded to an inner wall of the housing.

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