JP2000283581A - Cold storage refrigerator and refrigerating unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress influence onto the peripheral field by forming the core of a first piston of a specific material and filling a first gas channel formed in the side wall of a first cylinder with a first cold storage material for exchanging heat with refrigerant gas. SOLUTION: A first stage piston 31 inserted into a first stage cylinder 30 defines a first stage expansion chamber 35 at the end of a second stage cylinder 40 and couples the high temperature end of the second stage piston 48 with the first stage piston 31 through a coupling member 32. The columnar core part 48a of the second stage piston 48 is formed of a material selected from a group of polyether etherketone, polyamideimide, polyetherimide, and glass fiber reinforced epoxy. The gas channel 43 of a cold head 41 interconnects a gas channel 45 and a second stage expansion chamber 50 and the gas channel 44 of a stop ring 46 interconnects the first stage expansion chamber 35 and the gas channel 45. The gas channel 45 is filled with cold storage materials 51, 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a regenerator refrigerator, and more particularly to a regenerator refrigerator in which a piston reciprocates in a cylinder and absorbs heat at a low temperature end of the cylinder.

[0002]

2. Description of the Related Art FIG. 2 is a sectional view of a conventional two-stage GM refrigerator. The helium compressor 10 compresses helium gas to a pressure of about 20 kgf / cm ² and supplies high-pressure helium gas. High pressure helium gas is supplied to the intake valve V1,
The gas is supplied into the first-stage cylinder 11 through the gas passage 16. The first-stage cylinder 11 includes the second-stage cylinder 1
2 are connected.

[0003] A first-stage displacer 13 and a second-stage displacer 14 that are connected to each other are inserted into the first-stage cylinder 11 and the second-stage cylinder 12, respectively. The first-stage displacer 13 defines an expansion space 21 on the second-stage cylinder 12 side in the first-stage cylinder 11, and defines a high-temperature side space 27 on the opposite side. The shaft member S extends from the end of the first-stage piston 13 on the high-temperature-side space 27 side to the outside of the first-stage cylinder 11. The shaft member S is connected to a crank mechanism 15 driven by a driving motor M. The second-stage displacer 14 defines an expansion space 22 at an end of the second-stage cylinder 12 that is not connected to the first-stage cylinder 11.

[0004] Cavities 17 and 18 are formed in the first stage displacer 13 and the second stage displacer 14, respectively. The cavities 17 and 18 are filled with cold storage materials 25 and 26, respectively. The cavity 17 communicates with the high-temperature side space 27 via the gas flow path 23a,
It communicates with the expansion space 21 via 3b. Cavity 18
Communicates with the expansion space 21 via the gas flow path 24a and communicates with the expansion space 22 via the gas flow path 24b.

Usually, the first-stage cylinder 11 and the second-stage cylinder 12 are made of stainless steel (for example, SU) having sufficient strength, low thermal conductivity, and sufficient helium gas shielding ability.
S304) and the like. The first-stage displacer 13 and the second-stage displacer 14 are formed of phenol (bakelite) containing cloth having a low specific gravity, sufficient abrasion resistance, relatively high strength, and low thermal conductivity.

Although not shown, a seal ring is arranged between the outer peripheral surface of the first stage displacer 13 and the inner peripheral surface of the first stage cylinder 11, and helium gas is transported through this gap. Is preventing that. Similarly, a similar seal ring is arranged between the second stage displacer 14 and the second stage cylinder 12.

A first-stage heat station 19 is thermally connected to the end of the first-stage cylinder on the side of the expansion space 21. A second-stage heat station 20 is thermally connected to an end of the second-stage cylinder 12 on the expansion space 22 side.

The high-pressure helium gas supplied from the helium compressor 10 through the intake valve V 1 is introduced into the high-temperature space 27 in the first-stage cylinder 11 through the gas passage 16. The helium gas introduced into the high-temperature side space 27 is
The gas is transported into the first-stage expansion space 21 through the gas flow path 23a, the cavity 17, and the gas flow path 23b. When the helium gas moves in the space 17, heat exchange is performed between the cold storage material 25 and the helium gas.

The helium gas in the first-stage expansion space 21 is further supplied to the gas passage 24 a, the cavity 18, and the gas passage 2.
4b, and is transported into the second-stage expansion space 22.
As the helium gas moves through the cavity 18, heat exchange occurs between the cold storage material 26 and the helium gas. The gas flow paths 23 and 24 shown in FIG. 2 are functionally described for explaining the flow of the refrigerant gas, and are different from the actual structure.

When the intake valve V1 is closed and the exhaust valve V2 is opened, the high-pressure helium gas in the second-stage cylinder 12 and the first-stage cylinder 11 flows along a path reverse to that in the case of intake. The gas is recovered by the helium compressor 10 via the passage 16 and the exhaust valve V2.

During operation of the GM type refrigerator, the first stage displacer 13 and the second stage displacer 14 are reciprocally driven in the axial direction of the cylinder as indicated by arrows in the figure by the rotation of the drive motor M. You. When the first-stage displacer 13 and the second-stage displacer 14 are driven downward, the intake valve V1 opens, and high-pressure helium gas is supplied into the first-stage cylinder 11 and the second-stage cylinder 12.

When the first-stage displacer 13 and the second-stage displacer 14 are driven upward by the drive motor M, the intake valve V1 is closed and the exhaust valve V2 is opened.
Helium gas is collected by the helium compressor 10. Thereby, the first-stage cylinder 11 and the second-stage cylinder 1
The pressure in the expansion space in 2 becomes low. At this time, the expansion space 21,
In 22, the helium gas expands to cause cold. The cooled helium gas is supplied to the cavities 18 and 17
When moving inside, the cool storage materials 26 and 25 are cooled.

The high-pressure helium gas supplied in the next intake step is cooled by exchanging heat with the cold storage materials 17 and 18 and is introduced into the expansion spaces 21 and 22. In the next exhaust process,
The expansion of the cooled helium gas further promotes cooling. In the steady state, the first cylinder 1
One expansion space 21 is maintained at a temperature of, for example, about 40K to 70K, and the expansion space 22 of the second stage cylinder 12 is maintained at a temperature of about several K to 20K.

[0014]

In order to enhance the refrigerating performance, a magnetic regenerator is disposed near the low-temperature end of the cavity 18 in the second stage displacer 14. The magnetic regenerator also reciprocates following the reciprocating motion of the displacer. For this reason, the magnetic field around the low-temperature end fluctuates with time. Therefore, this GM refrigerator cannot be used for applications where the magnetic field must not fluctuate over time.

An object of the present invention is to provide a regenerator-type refrigerator capable of reducing the influence on the peripheral magnetic field.

[0016]

According to one aspect of the present invention, a first cylinder having an inner peripheral surface composed of a columnar surface and a first cylinder inserted into a space defined by the inner peripheral surface of the first cylinder. A first piston defining a first space between a first end of the first cylinder and a tip of the first piston, at least a core of which is a polyetheretherketone; The first piston formed of one material selected from the group consisting of polyamide imide, polyether imide, and glass fiber reinforced epoxy; and the first piston formed in a side wall of the first cylinder; A first gas flow path that communicates with the space and supplies the refrigerant gas into the first space, or recovers the refrigerant gas from the first space, and is filled in the first gas flow path; Refrigerant moving in the first gas flow path Regenerator refrigerator having a first cold accumulating material to perform a scan and heat exchange is provided.

Since the first cold storage material is disposed in the first cylinder, the cold storage material does not move even if the first piston reciprocates. For this reason, even if a magnetic regenerator material is used, the influence on an external magnetic field can be reduced. Further, since the first gas passage is formed in the side wall of the first cylinder,
The cross-sectional area can be increased as compared with the case where the piston is formed in the piston. When the cross-sectional area of the gas passage filled with the regenerator material is increased, the flow rate of the refrigerant gas is reduced, and the heat exchange efficiency can be increased. Since the linear expansion coefficient of the above material is relatively close to that of stainless steel, when the cylinder is formed of a material having a linear expansion coefficient close to that of stainless steel, the gap between the piston and the cylinder can be kept almost constant even at low temperatures. .

[0018]

FIG. 1 shows a G according to an embodiment of the present invention.
The sectional view of the 2nd stage of the M type refrigerator is shown. That is, FIG.
2 corresponds to the second-stage cylinder 12 and the second-stage displacer 14 of the conventional refrigerator shown in FIG. The first stage portion of the GM refrigerator according to the embodiment is the same as that shown in FIG. 2, and therefore is not shown in FIG.

A second-stage cylinder 40 having a smaller diameter than the first-stage cylinder 30 is connected to the cylindrical first-stage cylinder 30. The end of the second stage cylinder 40 that is connected to the first stage cylinder 30 is called a high temperature end, and the other end is called a low temperature end. The second stage cylinder 40 includes an outer cylindrical member 40a and an inner cylindrical member 40b. The outer cylindrical member 40a and the inner cylindrical member 40b are formed of, for example, stainless steel. A flange 42 is formed at one end of the outer cylindrical member 40 a, and its outer peripheral surface is in close contact with the inner peripheral surface of the first stage cylinder 30. Outer cylindrical member 40a
Is closed by a cold head 41.

The inner cylindrical member 40b is disposed within the outer cylindrical member 40a and coaxially therewith. A cylindrical gas flow path 45 is defined between the inner cylindrical member 40b and the outer cylindrical member 40a. The low temperature end of the inner cylindrical member 40 b is supported by the cold head 41.
At the high temperature end, a retaining ring 46 is loaded between the outer cylindrical member 40a and the inner cylindrical member 40a, and the position of the inner cylindrical member 40b is fixed.

A second stage piston 48 is inserted into the inner cylindrical member 40b. At the low-temperature end of the second-stage cylinder 40, a second-stage piston 48, a second-stage cylinder 40,
And second-stage expansion space 5 surrounded by cold head 41
0 is defined.

A first stage piston 31 is inserted into the first stage cylinder 30. The first-stage piston 31 is provided in the cavity of the first-stage cylinder 30 in the second-stage cylinder 40.
A first-stage expansion space 35 is defined at the side end. The high-temperature end of the second-stage piston 48 is connected to the first-stage piston 31 via the connection member 32.

The second stage piston 48 includes a solid cylindrical core portion 48a and a coating film 48b covering the column surface. The core 48a is formed of, for example, polyetheretherketone. The polyetheretherketone material is marketed by, for example, Japan Polypenco Co., Ltd. under the trade name of Polypenco PEEK. Coating film 48b
Is formed of a wear-resistant resin such as a Teflon-based coating agent. A spiral groove is provided on the surface of the coating film 48b. By providing the spiral groove, the gas flowing in the gap between the second stage piston 48 and the inner cylindrical member 40b flows along the spiral groove. Thereby, the refrigerating performance can be improved. The effect of providing a helical groove is described in
No. 59684 describes this in detail.

A gas passage 43 is formed in the cold head 41. The gas passage 43 communicates the gas passage 45 with the second-stage expansion space 50. Gas flow path 4 in retaining ring 46
4 are formed. The gas flow path 44 connects the first-stage expansion space 35 to the gas flow path 45. When viewed along the axis of the cylinder, the gas flow paths 43 and 44 are configured by, for example, about eight through holes arranged at equal intervals.

The first cold storage material 51 is filled in the vicinity of the low-temperature end of the gas passage 45, and the second cold storage material 52 is filled in other portions. The first regenerative material 51 is, for example, a magnetic regenerative material whose specific heat increases at a temperature of about 4K, and the second regenerative material 52 is, for example, a lead ball. The boundary between the portion filled with the first cool storage material 51 and the portion filled with the second cool storage material 52 is separated by felt 55 so that the two are not mixed. The boundary between the gas flow paths 45 and 43 is partitioned by a felt 54 and a wire mesh 53, and the boundary between the gas flow paths 45 and 44 is partitioned by a felt 57 and a wire mesh 56. Thereby, the first cool storage material 51 and the second cool storage material 52 are held in the gas flow passage 45.

In the embodiment shown in FIG. 1, helium gas is supplied from the first-stage expansion space 35 to the gas passages 44, 45 and 43.
Is supplied into the second-stage expansion space 50, and is recovered from the second-stage expansion space 50 into the first-stage expansion space 35 by following the reverse flow path. Even if the second stage piston 48 reciprocates, the first cold storage material 51 having magnetism does not move.
Therefore, the influence on the external magnetic field can be reduced.

The regenerator material is generally formed of a heavy metal. When the cold storage material is filled in the displacer (piston) as shown in the conventional example of FIG. 2, the piston becomes heavy. In the case of the present embodiment, it is not necessary to fill the piston with cold storage material, so that the piston can be made lighter.
For this reason, even if the piston is reciprocated, the amount of movement of the center of gravity of the entire refrigerator becomes small, and vibration can be reduced. Further, the load applied to the movable part is reduced, which leads to improvement in reliability.

The core 48a of the second stage piston 48
Is relatively close to the linear expansion coefficient of stainless steel. The heat contraction amounts of the cylinder and the piston become substantially equal, and the gap between them can be kept constant. Similar effects can be expected by using polyamide imide, polyether imide, or glass fiber reinforced epoxy in addition to polyether ether ketone.

Furthermore, in this embodiment, since the cylinder has a double structure, even if the outer peripheral surface of the cylinder is deformed by an external impact, the inner cylinder surface can be prevented from being deformed.

Further, by adopting the structure of this embodiment, it becomes possible to increase the cross-sectional area of the gas flow passage in which the cold storage material is disposed. Increasing the cross-sectional area of the gas flow path decreases the moving speed of the refrigerant gas. Therefore, the heat exchange efficiency between the refrigerant gas and the cold storage material can be increased.
When the cross-sectional area of the gas flow path is increased, the flow path resistance is reduced, and the pressure loss can be reduced. For this reason, it is possible to increase the PV work.

In FIG. 1, the diameter of the second stage piston 48 is 25 mm, and the outer diameter of the inner cylindrical member 40b is 32 m.
m, the case where the inner diameter of the outer cylindrical member 40a is 45.5 mm is considered. At this time, the cross-sectional area of the gas passage 45 is about 8
22 mm ² . On the other hand, the second stage piston 48
Has a cross-sectional area of 491 mm ² . When the second stage piston is filled with the cold storage material as in the conventional example shown in FIG.
The cross-sectional area of the gas passage cannot be made larger than 491 mm ² . By providing the gas flow path in the side wall of the cylinder as in this embodiment, the cross-sectional area of the gas flow path can be increased without depending on the cross-sectional area of the piston. In order to obtain a sufficient effect of increasing the cross-sectional area of the gas flow path,
It is preferable that the cross-sectional area of the gas passage 45 be larger than the cross-sectional area of the piston.

In the embodiment shown in FIG. 1, the second stage piston and cylinder of the two-stage GM refrigerator have been described. However, the first stage piston and cylinder may have the structure shown in the embodiment of FIG. Good. More generally, some or all of the stages of the n-stage GM refrigerator may have the structure shown in FIG.

In the above embodiment, the GM refrigerator has been described as an example. However, the structure of the above embodiment can be applied to a refrigerator having a cylinder, a piston, and a regenerator, for example, a Stirling refrigerator.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0035]

As described above, according to the present invention,
By filling the cold storage material not in the movable piston but in the side wall of the fixed cylinder, a highly reliable cold storage device can be obtained. When a magnetic material is used as the cold storage material, the influence on the external magnetic field can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a second stage of a GM refrigerator according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional GM refrigerator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Helium compressor 11 1st stage cylinder 12 2nd stage cylinder 13 1st stage displacer 14 2nd stage displacer 15 Crank mechanism 16,23,24 Gas flow path 17,18 Cavity 19,20 Heat station 21, 22 Expansion space 25, 26 Cold storage material 27 High temperature side space 30 First stage cylinder 31 First stage piston 32 Connecting member 35 First stage expansion space 40 Second stage cylinder 41 Cold head 42 Flange 43, 44, 45 Gas flow path 48 Second stage piston 50 Second stage expansion space 51 First cold storage material 52 Second cold storage material 53, 56 Wire mesh 54, 55, 57 Felt

Claims (7)

[Claims] A first cylinder having an inner peripheral surface formed of a columnar surface; and a first piston inserted into a space defined by an inner peripheral surface of the first cylinder, wherein the first piston is inserted in a space defined by the inner peripheral surface of the first cylinder. Between the first end of the cylinder and the tip of the first piston.
At least the core is a polyetheretherketone, a polyamideimide, a polyetherimide,
And a first piston formed of one material selected from the group consisting of: a glass fiber reinforced epoxy, and a first piston formed in a side wall of the first cylinder, communicating with the first space, A first gas flow path for supplying a refrigerant gas into the first space or collecting the refrigerant gas from the first space; and a first gas flow path filled in the first gas flow path. A regenerator-type refrigerator having a refrigerant gas moving inside and a first regenerator material performing heat exchange. 2. The first cylinder includes an inner cylindrical member and an outer cylindrical member, and the first cylinder is disposed between an outer peripheral surface of the inner cylindrical member and an inner peripheral surface of the outer cylindrical member. The regenerative refrigerator according to claim 1, wherein one refrigerating refrigerator is defined. 3. The first cylinder of claim 1, further comprising:
A second cylinder coupled to a second end opposite to the end of the second cylinder and defining an internal cavity communicating with the first space via the first gas flow path; A second piston inserted into the cylinder, the tip of which defines a second space communicating with the first gas flow path; and a second piston communicating with the second space, A second gas flow path for supplying the refrigerant gas into the second space or recovering the refrigerant gas from the second space; and a second gas filled in the second gas flow path, 3. The regenerator according to claim 1, further comprising a refrigerant gas moving in the flow path and a second regenerator material that exchanges heat. 4. 4. The first gas flow path formed on an outer peripheral surface of the first piston and between an outer peripheral surface of the first piston and an inner peripheral surface of the first cylinder. The regenerator according to any one of claims 1 to 3, further comprising a spiral groove that defines a spiral gas flow path connected in parallel. 5. The regenerator according to claim 1, wherein the first cylinder is formed of stainless steel. 6. A first cylinder having an inner peripheral surface formed of a columnar surface, and a first piston inserted into a space defined by an inner peripheral surface of the first cylinder, wherein the first piston is provided in the first cylinder. Between the first end of the cylinder and the tip of the first piston.
The first piston defining a space, and formed in a side wall of the first cylinder and communicating with the first space to supply a refrigerant gas into the first space; or A first gas flow path for recovering the refrigerant gas from the space, and a first regenerative cooler which is charged in the first gas flow path and exchanges heat with the refrigerant gas moving in the first gas flow path Material, the area of the cross section of the first gas flow path orthogonal to the axis of the first cylinder, the area of the cross section of the first piston orthogonal to the axis of the first cylinder Larger regenerator refrigerator. 7. A cylinder made of stainless steel, and inserted into the cylinder, at least a core of which is made of one material selected from the group consisting of polyetheretherketone, polyamideimide, polyetherimide, and glass fiber reinforced epoxy. A device having a piston formed.