JP2003028526A - Cool storage unit and refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problems in a cool storage unit using a metal mesh as a cool storage material that a packing rate of the cool storage material is relatively low since the individual meshes themselves have openings, and that the performance of the unit is hard to improve since an ineffective space not contributing to the cool storage is relatively large. SOLUTION: The metal mesh made to have a thin wall by pressing is used as the cool storage material. This cool storage material is stacked and packed in a tubular vessel for the cool storage unit and thereby the packing rate of the cool storage material in the unit is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerator and a refrigerator, and more particularly to a regenerator using a metal mesh as a regenerator material and a refrigerator using a metal mesh as a regenerator material.

[0002]

2. Description of the Related Art Refrigerators such as Gifford-McMahon refrigerators (hereinafter abbreviated as "GM refrigerators"), Stirling refrigerators, pulse tube refrigerators, etc., use a regenerator filled with a regenerator material. Utilize to get low temperature.

For example, in a GM refrigerator, a compressed working fluid (refrigerant gas) is supplied to an expander having a displacer piston equipped with a regenerator and a cylinder into which the displacer piston is inserted, and the working fluid (refrigerant is referred to as a refrigerant). Gas) is adiabatically expanded in the expander to obtain cold.

The number of stages of the regenerator used is appropriately selected according to the temperature of cold to be obtained and the kind of regenerator material used in the regenerator is also appropriately selected. For example, in a refrigerator of a type that uses only one regenerator, a large number of metal meshes formed by thin metal wires having a circular cross section, a large number of lead balls, etc. are mainly used as a regenerator material.

[0005]

When a large number of metal meshes are used as the regenerator material, these metal meshes are filled in a tubular container for a regenerator in a state of being laminated in the longitudinal direction of the tubular container. It In order to prevent a gap from being generated between the metal meshes, these metal meshes are sequentially filled while occasionally pressing the metal mesh that has been laminated in the cylindrical container with a press or the like.

However, since the metal mesh itself has a gap in the first place, the filling rate of the regenerator material in the regenerator using the metal mesh is relatively low. For example, if the wire diameter is 0.05
When a metal mesh having a mesh size of 1 mm and a mesh size of # 180 is used, the filling rate is about 28%.

From the standpoint of improving the performance of the regenerator, it is desired to increase the filling rate of the regenerator material.

An object of the present invention is to provide a regenerator capable of increasing the filling rate of the regenerator material.

Another object of the present invention is to provide a refrigerator capable of increasing the filling rate of the regenerator material.

[0010]

According to one aspect of the present invention, a hollow cylindrical member is provided with a gas flow port at one end in the lengthwise direction or in the vicinity thereof and in the other end or in the vicinity thereof. It is composed of a container and a plurality of first metal meshes stacked and filled in the cylindrical container in the lengthwise direction of the cylindrical container, and each of the first metal meshes is pressed. A regenerator including a first regenerator material layer is provided.

According to another aspect of the present invention, there is provided a hollow cylindrical container having a gas flow port at or near one end in the length direction and at or near the other end, and the above-mentioned cylinder. Of a plurality of thin metal wires each having a circular cross section, the plurality of first metal meshes being stacked and filled in the cylindrical container in the lengthwise direction of the cylindrical container. A first regenerator material layer, which is a woven fabric, in which curved surfaces or flat surfaces having a larger radius of curvature than other locations are formed above and below in the thickness direction at the intersection of two thin metal wires in the first metal mesh. A regenerator including and is provided.

According to still another aspect of the present invention, a compressor for generating a compressed refrigerant gas and a supply of the compressed refrigerant gas from the compressor are provided, and the refrigerant gas is adiabatically expanded to cool the refrigerant. (I) a cylinder, and (i
i) a piston that is inserted into the cylinder and that reciprocates while defining a first space at one end of the cylinder and a second space at the other end of the cylinder; and A gas flow path formed between the first space and the second space;
v) a first metal mesh composed of a plurality of first metal meshes that are stacked and filled in the gas flow passage in the flowing direction of the refrigerant gas, and each of the first metal meshes is pressed. A refrigerator provided with a cold storage material layer is provided.

According to still another aspect of the present invention, a compressor for generating a compressed refrigerant gas and a supply of the compressed refrigerant gas from the compressor are provided, and the refrigerant gas is adiabatically expanded to cool the refrigerant. (I) a cylinder, and (i
i) a piston that is inserted into the cylinder and that reciprocates while defining a first space at one end of the cylinder and a second space at the other end of the cylinder; and A gas flow path formed between the first space and the second space;
v) is composed of a plurality of first metal meshes stacked and filled in the gas flow path in the flowing direction of the refrigerant gas, each of the first metal meshes having a large number of circular cross sections. A woven fabric of thin metal wires, wherein curved surfaces or flat surfaces having a larger radius of curvature than other locations are formed above and below in the thickness direction at the intersection of two thin metal wires in the first metal mesh. A refrigerator having an expander including a cold storage material layer is provided.

By using the metal mesh thinned by press processing as the regenerator material, it is possible to obtain a regenerator with an improved filling rate of the regenerator material. Since the ineffective space that does not contribute to the cold storage in the regenerator is reduced, the performance of the regenerator can be improved.

Whether or not the metal mesh has been subjected to a press treatment can be determined by observing a portion where two metal fine wires intersect each other in this metal mesh. In the pressed metal mesh, a curved surface or a flat surface having a larger radius of curvature than other portions is formed above and below in the thickness direction at the intersection of two thin metal wires.

[0016]

1 is a sectional view schematically showing a regenerator according to an embodiment. The regenerator 20 shown in the figure has a cylindrical container 7 constituted by a bottomed cylindrical main container 1 and a lid portion 5 that closes the open end side of the main container 1, and the inside of the cylindrical container 7. And the filled cold storage material layer 9.

The main container 1 is made of, for example, phenol resin, and has, for example, three gas flow holes 2a at its bottom.
And a fitting portion 3 into which one end of the piston rod is fitted when forming a displacer piston described later. A groove 4 for mounting a sealing material is formed annularly on the side wall on the bottom side of the main container 1, and a large number of gas circulation holes 2b are radially formed on the side wall on the lid part 3 side. In FIG. 1, one gas flow hole 2a and two gas flow holes 2 are provided.
b is visible.

The lid portion 5 is made of, for example, a phenol resin, and the lid portion 5 closes the open end of the main container 1 at the tip side of the location where the gas flow hole 2b is formed.

Regenerator material layer 9 filled in the cylindrical container 7.
Is, in order from the lid 5 side, (a) a # 16 mesh formed by a large number of red copper wires (copper-zinc alloy in which zinc is added to copper in an amount of 5 to 20%) having a diameter of 0.55 mm. 4 sheets of metal mesh 9a, (b) Regenerator material layer 9b composed of 320 pieces of # 200 mesh metal mesh formed by a large number of fine red copper wires having a wire diameter of 0.053 mm,
(c) Regenerator material layer 9c composed of 970 pieces of # 200 mesh metal mesh formed by a large number of fine red copper wires having a wire diameter of 0.053 mm, and (d) a large number of wire diameters of 0.55 mm. Formed by fine red copper wire #
It has two 16-mesh metal meshes 9d.

The cylindrical container 7 has an inner diameter of 72.3 mm and a depth of 145 mm, and the maximum size of each metal mesh is about 72.3 mm. The thickness of the cold storage material layer 9b is about 30 mm
The thickness of the cold storage material layer 9c is about 110 mm.

Of the metal meshes forming the four cold storage material layers (a) to (d), each metal mesh forming the cold storage material layer 9b in (b) is subjected to a press treatment. There is.

FIG. 2A is a side view schematically showing the metal mesh 10 constituting the cold storage material layer 9b.
(B) is a plan view schematically showing the metal mesh 10.

As shown in these figures, the metal mesh 1
0 is a plain woven fabric of a large number of fine red copper wires 11, and the crossing portion of two fine red copper wires 11 and the vicinity thereof are compressed in the thickness direction by a pressing process. A curved surface or a flat surface having a larger radius of curvature than other portions is formed above and below in the thickness direction at the portion compressed by the pressing process.
In FIGS. 2A and 2B, the curved surface or the flat surface is denoted by reference numeral “11a”.

The thickness of the metal mesh 10 at the intersection of the two fine red copper wires 11 is about 0.086 mm. This value is the fine copper wire 11 in the part that is not pressed.
Is about 1.5 times the wire diameter of 0.053 mm. When the pressing process is not performed, the thickness at the intersection of the two fine copper wire 11 is about 0.13 mm, which means that the pressing process reduces the thickness by about 34%.

By forming the regenerator material layer by using the metal mesh whose thickness is reduced by the press treatment, it is possible to improve the filling rate of the regenerator material as compared with the case where the metal mesh not subjected to the press treatment is used. For example, when the metal mesh 10 whose thickness is reduced by about 34% by the press treatment as described above is used, the filling rate of the regenerator material is about 1. compared to the case where the metal mesh which is not pressed is used.
It can be improved up to 5 times. The amount of ineffective space that does not contribute to cold storage in the regenerator is reduced, so that the performance of the regenerator can be improved.

The metal mesh subjected to the press treatment can be produced, for example, by rolling the original wire mesh with a pair of rolls and then punching it into a desired size. A press machine such as a hydraulic press machine or a mechanical press machine may be used instead of the pair of rolls.

In the press treatment, in other words, the maximum thickness of the wire mesh which is the source of the metal mesh (thickness at the portion where the two metal thin wires intersect) is reduced by approximately 5 to 50%. If so, the thickness at the intersection of the two thin metal wires is approximately 0. 1 of the wire diameter of the single thin metal wire in the non-pressed portion.
It is preferable to set the pressing conditions so that the pressing ratio is 95 to 0.5 times.

A metal mesh having a small warp can be obtained by punching as it is without winding the wire net after the press treatment. It is possible to obtain a metal mesh that can be easily filled into a tubular container for a regenerator.

When the regenerator is used, a working fluid (refrigerant gas) flows inside. As the filling rate of the regenerator material in the regenerator increases, it becomes difficult for the refrigerant gas to flow through the regenerator. When it becomes difficult for the refrigerant gas to flow through the regenerator,
The performance of the regenerator, and eventually the performance of the refrigerator using this regenerator, may deteriorate.

Of course, when a metal mesh is used as the regenerator material, in addition to the filling rate of the metal mesh, the roughness (mesh size) of the metal mesh also affects the flowability of the refrigerant gas in the regenerator. Exert.

On the high temperature side (the side far from the cooling stage described later) in the regenerator, the flow rate of the refrigerant gas is higher than that on the low temperature side, so that the flow of the refrigerant gas is not disturbed especially on the high temperature side. It is preferable to select the filling rate of the metal mesh and the mesh roughness (mesh size) of each metal mesh.

The cylindrical container 7 constituting the regenerator 20 shown in FIG. 1 is designed so that the lid 5 is on the low temperature side and the bottom of the main container 1 is on the high temperature side when used. The cold storage material layer 9b configured by the pressed metal mesh 10 (see FIGS. 2A and 2B) is arranged on the lid 5 side and configured by the unpressed metal mesh. The material layer 9c is arranged on the bottom side of the main container 1. In the regenerator 20, the filling rate of the metal mesh on the high temperature side where the flow rate of the refrigerant gas is high is lower than the filling rate on the low temperature side. Therefore, the circulation of the refrigerant gas in the regenerator 20 is unlikely to be hindered.

Next, the refrigerator according to the embodiment is shown in FIG.
Will be described with reference to.

FIG. 3 schematically shows the structure of the refrigerator according to the embodiment. The refrigerator 100 shown in the figure receives a compressor 30 that generates a compressed refrigerant gas (hereinafter, referred to as “compressed refrigerant gas”), and a supply of the compressed refrigerant gas from the compressor 30. This is a one-stage GM refrigerator including an expander 50 that is adiabatically expanded to obtain cold, and a power chamber 90 that is disposed on the expander 50. As the refrigerant gas, for example, helium gas is used.

The expander 50 has a cylinder 60 and a displacer piston 70 inserted in the cylinder 60.

The cylinder 60 comprises a cylindrical portion 63 made of a rigid material having a low heat conductivity and a high airtightness, such as stainless steel, a cooling stage 65 made of copper for closing one end of the cylindrical portion 63, and a cylinder. It is composed of a flange portion 67 fixed to the other end of the portion 63. The cylinder 60 has an inner diameter of 82 mm and a length (inner dimension) of 250 mm. The cylinder 60 is housed in a vacuum container (not shown).

The displacer piston 70 is, for example,
The regenerator 20 shown in FIG. 1, the piston rod 73, and the sealing material 75 are used. Piston rod 73
Is fitted into a fitting portion 3 (see FIG. 1) formed on the bottom of the main container 1 that constitutes the regenerator 20, and is fixed by a fixture (not shown). The sealing material 75 is mounted in the groove 4 (see FIG. 1) formed in the main container 1. Seal material 75
Is, for example, an annular slipper seal.

The regenerator 20 is inserted into the cylinder 60 so that the lid 5 forming the cylindrical container 7 is located on the cooling stage 65 side.

The other end of the piston rod 73 is connected to a crank (not shown), which is connected to the cylinder 6
It is connected to the rotating shaft of the motor M in the power chamber 90 arranged on the flange 67 so as to close the open end of 0. The motor M generates power for reciprocating the displacer piston 70 in the axial direction of the cylinder 50.

The displacer piston 70 is the regenerator 2
0 and the outer surface of the lid 5 and the cooling stage 65
A reciprocating motion is performed while always forming a space 80 between the inner bottom surface and the inner bottom surface. The size of the space 80 changes as the displacer piston 70 reciprocates. Hereinafter, this space 80 is referred to as a low temperature part side space 80.

Similarly, the displacer piston 70 is
The reciprocating motion is performed while always forming a space 85 between the outer bottom surface of the main container 7 constituting the regenerator 20 and the outer surface of the housing 92 defining the power chamber 90. Space 85
The width of the space changes with the reciprocating motion of the displacer piston 70. Hereinafter, this space 85 will be referred to as the high temperature part side space 8
5

Two valves V1 and V are provided in the power chamber 90.
A rotary valve device V including 2 is provided.
The rotary valve device V receives power from the motor M, for example.

A pipe 40 is connected to one end of each of the valves V1 and V2, and the other end of each of the valves V1 and V2 is discharged from a compressed refrigerant gas supply pipe 42 or an expander 50 to which compressed refrigerant gas is supplied from the compressor 30. A refrigerant gas recovery pipe 44 that receives the supply of the refrigerant gas is connected. One end of the pipe 40 is
It is connected to an opening 92a formed in the bottom of the housing 92.

The compressed refrigerant gas produced by the compressor 30 is
The compressed refrigerant gas is supplied from the opening 92a into the cylinder 60 through the compressed refrigerant gas supply pipe 42, the rotary valve device V (valve V1) and the pipe 40. The refrigerant gas supplied into the cylinder 60 reaches the high temperature side space 85, the regenerator 20 and the low temperature side space 80.

The refrigerant gas supplied into the cylinder 60 is
It is discharged from the opening 92a to the outside of the cylinder 60 at a predetermined timing. The discharged refrigerant gas is recovered by the compressor 30 via the pipe 40, the rotary valve device V (valve V2) and the refrigerant gas recovery pipe 44. The refrigerant gas recovered by the compressor 30 is reused.

The timing of supplying the compressed refrigerant gas to the inside of the cylinder 60 and the timing of discharging the refrigerant gas to the outside of the cylinder 60 are controlled by, for example, the rotary valve device V.

During operation of the refrigerator 100, the cylinder 60
The supply of the compressed refrigerant gas to the inside and the discharge of the refrigerant gas from the cylinder 60 are repeatedly performed with the reciprocating motion of the displacer piston 70 and a predetermined phase difference. As the displacer piston 70 reciprocates, heat is absorbed in the low temperature part side space 80. As the cooled refrigerant gas passes through the inside of the regenerator 20, the regenerator material is gradually cooled, and eventually reaches a substantially constant temperature. The temperature of the outer surface of the cooling stage 65 also becomes a substantially constant temperature.

In order to test the cooling capacity of the refrigerator 100, various heat loads of various sizes are applied to the cooling stage 65 while operating the refrigerator 100 under the following conditions, and the ultimate temperature of the cooling stage 65 is set to 35K. The value of the heat load that can be maintained was determined. At this time, helium gas (filling pressure 1.72 MPa) was used as the refrigerant gas, and the frequency of the reciprocating motion of the displacer piston 70 was 1.2 Hz.

As a result, even when a heat load of 63.7 W was applied, the temperature reached by the cooling stage 65 was maintained at 35K.

For comparison, the press-processed cold storage material layer 9b shown in FIG. 1 is not formed, but instead, the number of metal meshes constituting the unpressed cold storage material layer 9c is increased to 1220. The regenerator was manufactured. Refrigerator 1 except that the displacer piston 70 is configured using this regenerator
The cooling capacity of the refrigerator having the same configuration as that of No. 00 was tested under the same conditions as above.

As a result, in this refrigerator, the heat load capable of maintaining the reached temperature of the cooling stage 65 at 35K is 56.1.
It was W.

As is apparent from these tests, the performance of the refrigerator can be improved by using the regenerator in which the filling rate of the regenerator material is increased by using the metal mesh thinned by the press treatment.

Although the regenerator and refrigerator according to the embodiments have been described above, the present invention is not limited to these embodiments.

For example, the metal mesh to be pressed is
The metal mesh is not limited to red copper, but may be copper, stainless steel, phosphor bronze, or the like.

The mesh roughness (mesh size) of the metal mesh depends on the performance required for the regenerator to be manufactured,
Usage position in the regenerator (for example, low temperature side or high temperature side)
It can be appropriately selected according to the above. The same applies to the wire diameter of the metal thin wire that constitutes the metal mesh.

It is possible to construct one regenerator using only one type of metal mesh that has been pressed as a regenerator material, or to use a plurality of types of regenerator material layers that are composed of pressed metal mesh. It is also possible to form in one regenerator. "Multiple types of cold storage material layers" here
Means a plurality of cold storage material layers in which the material, wire diameter, or mesh size of the metal mesh (pressed) constituting the cold storage material layer is different for each cold storage material layer.

It is also possible to dispose a regenerator material layer composed of a pressed metal mesh and a regenerator material layer composed of a large number of granular regenerator materials in one regenerator.

The displacer piston may be a one-stage type having only one regenerator or a two-stage type having two regenerators connected to each other. It is also possible to connect three or more regenerators to form a displacer piston. When using two or more regenerators,
A regenerator using a metal mesh as a regenerator material is usually arranged on the high temperature side. The first stage displacer piston of the two-stage GM refrigerator was loaded with a metal mesh as a regenerator material, and the second stage disperser piston was filled with lead balls and a magnetic regenerator material as a regenerator material. When all the loaded metal meshes were pressed, it was possible to load 1161 metal meshes (equivalent to the metal mesh 9b shown in FIG. 1). When the pressing process was not performed, the number of loaded metal meshes (equivalent to the metal mesh 9c shown in FIG. 1) was 774. When this GM refrigerator was operated at 1.0 Hz, the cooling capacity of the first cooling stage of the GM refrigerator using the metal mesh subjected to the press treatment was 47.5W. On the other hand, the cooling capacity of the first cooling stage of the GM refrigerator using the non-pressed metal mesh is 37.
It was 5W. The second cooling stage reached 4K or less in any case. As described above, the cooling capacity can be enhanced by using the metal mesh subjected to the press treatment.

For example, a gas flow path connecting the high temperature part side space 85 and the low temperature part side space 80 shown in FIG. 3 is provided outside the cylinder 60, and a part of this gas flow path is constituted by the regenerator 20. Is also possible. In this case, a normal piston is used instead of the displacer piston 70. The regenerator 20 is arranged such that the regenerator material layer 9b is on the low temperature portion side and the regenerator material layer 9c is on the high temperature portion side.

The regenerator using the pressed metal mesh as a regenerator material can be used in, for example, a Stirling refrigerator or a pulse tube refrigerator in addition to the GM refrigerator.

It will be apparent to those skilled in the art that various other modifications, improvements, combinations and the like can be made.

[0062]

As described above, according to the present invention, the filling rate of the regenerator material can be increased and the performance of the regenerator can be improved. By using this regenerator, it becomes easy to obtain a refrigerator with high cooling capacity.

[Brief description of drawings]

FIG. 1 is a sectional view schematically showing a regenerator according to an embodiment.

FIG. 2 (A) is a side view schematically showing a pressed metal mesh, and FIG. 2 (B) is a plan view schematically showing a pressed metal mesh.

FIG. 3 is a schematic diagram showing a refrigerator according to an embodiment.

[Explanation of symbols]

7 ... Cylindrical container, 9 ... Regenerator material layer, 10 ... Pressed metal mesh, 11 ... Metal fine wire (red copper fine wire), 2
0 ... Regenerator, 30 ... Compressor, 50 ... Expander, 80 ...
Low temperature side space, 85 ... High temperature side space, 100 ... Refrigerator.

Claims (8)

[Claims] 1. A hollow cylindrical container provided with a gas flow port at one end in the lengthwise direction or in the vicinity thereof and in the other end or in the vicinity thereof, and the cylindrical container in the cylindrical container. A regenerator including a plurality of first metal meshes stacked and filled in the lengthwise direction, and each of the first metal meshes is pressed to form a first regenerator material layer. 2. A second regenerator material layer arranged in the cylindrical container adjacent to the first regenerator material layer,
The second container made up of a plurality of second metal meshes stacked in the lengthwise direction of the tubular container, each of the second metal meshes including a second cold storage material layer that has not been pressed. The regenerator described. 3. The first metal mesh is formed by pressing a woven fabric of a large number of fine metal wires, and the thickness at the intersection of the two fine metal wires is not pressed The regenerator according to claim 1 or 2, which has a diameter of 0.95 to 0.5 times the wire diameter of the thin metal wire. 4. A hollow cylindrical container provided with a gas flow port at one end or its vicinity and in the other end or its vicinity in the longitudinal direction, and the cylindrical container in the cylindrical container. A plurality of first metal meshes stacked and filled in the length direction of the first metal mesh, each of the first metal meshes being a woven fabric of a plurality of metal fine wires having a circular cross section, A regenerator including a first regenerator material layer in which a curved surface or a flat surface having a larger radius of curvature than other portions is formed above and below in a thickness direction at an intersection of two metal fine wires in a metal mesh. 5. A second regenerator material layer disposed in the cylindrical container adjacent to the first regenerator material layer,
The second cold storage material layer is composed of a plurality of second metal meshes stacked in the lengthwise direction of the tubular container, and each of the second metal meshes includes a second cold storage material layer that has not been pressed. The regenerator described. 6. The first metal mesh is a woven fabric of a large number of thin metal wires, and the thickness at the intersection of the two thin metal wires is 0. 95-0.
It is 5 times, The regenerator of Claim 4 or Claim 5. 7. A compressor that generates compressed refrigerant gas, and an expander that receives supply of the compressed refrigerant gas from the compressor and adiabatically expands the refrigerant gas to obtain cold. i) a cylinder; and (ii) a piston that is inserted into the cylinder and that reciprocates while defining a first space at one end of the cylinder and a second space at the other end. And (iii) a gas flow path formed between the first space and the second space, and (iv) a plurality of gas flow paths that are stacked and filled in the gas flow path in the flowing direction of the refrigerant gas. A refrigerator comprising: a first regenerator layer formed of a sheet of a first metal mesh, each of the first metal meshes being pressed. 8. A compressor that generates compressed refrigerant gas, and an expander that receives supply of the compressed refrigerant gas from the compressor and adiabatically expands the refrigerant gas to obtain cold. i) a cylinder; and (ii) a piston that is inserted into the cylinder and that reciprocates while defining a first space at one end of the cylinder and a second space at the other end. And (iii) a gas flow path formed between the first space and the second space, and (iv) a plurality of gas flow paths that are stacked and filled in the gas flow path in the flowing direction of the refrigerant gas. A plurality of first metal meshes, each of the first metal meshes is a woven fabric of a plurality of metal fine wires having a circular cross section, and an intersection of the two metal fine wires in the first metal mesh. On the upper and lower sides of the thickness direction of the Is an expander including a first regenerator material layer having a flat surface.