JPH0640772U - Low temperature regenerator - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a low-temperature regenerator used in a refrigerator that uses a refrigerant such as helium gas to increase the filling rate of regenerator material in the regenerator and to provide a highly efficient regenerator. . A container (4) having ventilation holes (7, 9) at both ends and an accommodation space inside, and a through hole portion (3) accommodated in the accommodation space of the container and formed of a cold storage material. And a plurality of plate-shaped bodies having a groove portion (2) continuous to the through hole portion, wherein the plurality of plates are arranged such that at least a part of projections of the through hole portion and the groove portion overlap each other when superposed. A cold storage material.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a low temperature regenerator, and more particularly to a low temperature regenerator used in a refrigerator using a refrigerant such as helium gas.

[0002]

[Prior art]

 Cryogenic refrigerators include Gifford-McMahon (GM) cycle refrigerators, solvee refrigerators and Stirling refrigerators, all of which have a displacer with a regenerator in the refrigeration cycle.

In the refrigeration cycle, the refrigerant gas passes through the regenerator before and after the endothermic process of adiabatically expanding the high-pressure refrigerant gas sent from the compressor, and at that time, heat exchange is performed with the regenerator material. As the refrigerant gas, helium gas or the like that does not liquefy even at an absolute temperature of 10 to 20 ° K.

FIG. 3 shows the structure of a conventional GM cycle refrigerator provided with a regenerator. Reference numeral 10 is a compressor, which compresses helium gas as a refrigerant. The compressed helium gas is cooled by the gas cooler 11, and the oil separator 12 further removes oil mist and the like mixed in the refrigerant gas.

The helium gas discharged from the oil separator 12 is introduced into a cold head 20 having a built-in regenerator through a pipe 14 via an intake valve 13 that opens and closes a pipe passage. The helium gas of the refrigerant that has exited the cold head 20 passes from the pipe 15 through the exhaust valve 16 that opens and closes the pipe passage, passes through the surge tank 17, and then returns to the inlet of the compressor 10 as a refrigerant gas at room temperature and pressure. . By repeating the above cycle, the tip of the cold head 20 is cooled and reaches an extremely low temperature.

Next, the structure of the cold head 20 will be further described. A displacer 22 having a regenerator as an inner container is arranged inside a cylinder 21 as an outer container. The displacer 22 is filled with the regenerator material 23 in its internal space.

The cold storage material 23 needs to have a material and a structure having a large heat capacity and a high heat exchange efficiency so that the cooling medium gas can pass through the inside. For this reason, copper alloy meshes are laminated or lead particles having a uniform particle size are filled. Reference numerals 24 and 25 are passages through which the refrigerant gas enters and leaves the regenerator material 23.

The displacer 22 is driven up and down inside the outer container 21 by a power unit (not shown) so as to reciprocate linearly between the top dead center and the bottom dead center. The top dead center is the point where the volume of the lower expansion chamber 28 is minimized, that is, the displacer moves to the bottom in the figure. FIG. 2 shows that the displacer 22 is located approximately in the middle between the top dead center and the bottom dead center.

A gas seal 27 is attached to the upper outer wall of the displacer 22, and when the refrigerant gas in the expansion chamber 28 that generates freezing flows in and out, the refrigerant gas passes through the gap between the displacer 22 and the outer container 21. Has an airtight seal to prevent movement.

Next, the GM refrigeration cycle will be described. First, the displacer 22 is at the position of the top dead center, and the intake valve 13 is gradually opened while the exhaust valve 16 is closed. The high-pressure helium refrigerant gas in the compressor 10 is introduced into the cold head 20 through the intake valve 13 and the pipe 14.

Next, when the displacer 22 is moved from the top dead center to the bottom dead center, the refrigerant gas passes through the passage 24 and the cold storage material 23. At that time, the refrigerant gas exchanges heat with the regenerator material 23, the heat is removed by the regenerator material 23, and passes through the passage 25 to reach the lower expansion chamber 28.

Next, while the displacer 22 is at the bottom dead center, the intake valve 13 is closed and the exhaust valve 16 is gradually opened, so that the high-pressure refrigerant gas enters the inlet side of the compressor 10. Due to the pressure difference, the temperature of the expansion chamber 28 is adiabatically expanded and the temperature of the expansion chamber 28 is lowered.

Further, when the displacer 22 is lowered from the bottom dead center toward the top dead center, the cooled refrigerant gas in the expansion chamber 28 receives the passage 25, the regenerator material 23, the passage 24, the pipe 15, the exhaust valve 16, and the surge. It flows to the tank 17 and the compressor 10. At that time, the refrigerant gas exchanges heat with the cold storage material 23 to cool the cold storage material 23. Cooling is performed by repeating the above refrigeration cycle.

In the Stirling refrigerator, the refrigerant gas whose pressure pulsates is directly supplied to the displacer without passing through a valve. The displacer reciprocates with the pulsating refrigerant gas out of phase to perform the refrigeration cycle. The displacer may be driven by an external drive source or may be arranged as a free piston.

When performing cryogenic cooling, spherical lead particles are often used in the cryogenic-side regenerator. When spherical particles are used as the regenerator material, the filling rate is about 60% even if they are filled using vibration or the like.

When reaching cryogenic temperatures, many materials sharply reduce their specific heat. For example, when cooling the refrigerant gas from about 30K to about 4K, it is desirable to use a cold storage material having a high specific heat in the temperature range of the gas to be contacted.

When attempting to realize high specific heat over a certain temperature range, it is effective to use several kinds of materials having high specific heat in each part of the temperature range as the cold accumulating material. In this case, the displacer is filled with several kinds of materials on the stack. However, if these materials are mixed, the effect will be reduced, so a partition is necessary to prevent mixing. Is.

[0018]

When attempting to fill a limited space of a regenerator with a regenerator material having a higher cooling capacity, it is desired to replenish as much regenerator material as possible. When a cold storage material having spherical particles is used, the filling rate is limited to about 60% as described above. When it is attempted to fill more regenerator material, it is desirable that the regenerator material has a shape other than spherical particles.

In addition, when several kinds of materials are used as the cold storage material, if a cold storage material of spherical particles is used, a partition is required. The use of partitions not only complicates the assembly, but if the partitions are broken during operation, the cold storage material is mixed and reliability is reduced.

An object of the present invention is to provide a highly efficient regenerator by increasing the filling rate of the regenerator material in the regenerator. Another object of the present invention is to provide a regenerator that is easy to assemble and reliable.

[0021]

[Means for Solving the Problems]

 The low temperature regenerator of the present invention comprises a container having ventilation holes at both ends and a housing space inside, a container housed in the housing space of the container, formed of a cold storage material, and connected to the through hole portion and the through hole portion. And a plurality of plate-shaped cold storage materials arranged such that at least a part of the projections of the through-hole portion and the groove portion overlap each other when they are overlapped with each other.

[0022]

[Action]

 By using a plurality of plate-shaped cold storage materials, the filling rate can be increased as compared with the case where spherical cold storage materials are used.

By providing the plate-shaped cold storage material with the groove portion and the through-hole portion continuous to the groove portion, the contact area between the plate-shaped cold storage material and the refrigerant can be sufficiently increased. At least a part of the projection of the through hole and the projection of the groove overlap each other, and a gas passage is secured. Therefore, a high cooling function can be realized.

[0024]

【Example】

 FIG. 1 shows the configuration of a plate-shaped cold storage material. FIG. 1 (A) is a top view showing the front side structure of the plate-shaped cold storage material, FIG. 1 (B) is a sectional view showing the cross-sectional structure of the plate-shaped cold storage material, and FIG. 1 (C) is the back surface of the plate-shaped cold storage material. It is a bottom view which shows the structure of.

The plate-shaped regenerator material 1 has a disc shape, and concentric grooves 2 are formed on the surface thereof. In the groove portion 2, a through hole portion 3 reaching from the bottom surface of the groove portion to the back surface is formed. The regenerator material 1 is produced, for example, by sintering a magnetic material containing a rare earth element, a transition metal or the like.

After the thin disk-shaped plate regenerator material 1 is formed by sintering, at least one surface thereof is made flat. A flat concentric circular groove 2 is formed in the plate-shaped cold storage material 1 with the flat plane facing down.

Subsequently, a large number of small through holes 3 reaching the bottom of the plate-shaped cool storage material from the bottom of the groove are formed. For example, the plate-shaped regenerator material 1 has a thickness of about 3 mm or less, and a groove 2 having a width of about 1 mm or less and a height of about 1 mm or less is formed on one surface thereof, and the bottom surface of the groove 2 has a diameter of about 1 mm or less. Through holes are formed. The distribution of the through holes can be variously changed according to the purpose, but any part of the plate-shaped regenerator material 1 is designed so that heat exchange can be efficiently performed with the refrigerant gas passing through the groove.

FIG. 2 shows the structure of the displacer. FIG. 2 (A) is a schematic cross-sectional view showing how the cold storage material is filled into the displacer, and FIGS. 2 (B) and 2 (C) are schematic cross-sectional views showing how the plate-shaped cold storage materials are stacked in the displacer. Is.

As shown in FIG. 2A, the displacer 4 is arranged in the cylinder 5 and is filled with the laminated plate-shaped cold storage material 1. The cylinder 5 is closed at one end and defines a cooling space 6 between the cylinder 5 and the displacer 4.

The displacer 4 has a cylindrical shape having an opening (ventilation hole) 7 through which a refrigerant gas passes on the cooling space side, and a lid member 8 forming a vent hole 9 is arranged at the other end. With the lid member 8 removed, the plate-shaped cool storage material 1 is stacked on the displacer 4, and the lid member 8 is pushed in to fix the plate-shaped cool storage material 1. In addition, a vent hole 9 is provided on the cover member 8 side of the displacer 4 for allowing a refrigerant gas to pass therethrough.

The plate-shaped cold storage material has a structure as shown in FIG. 1, but the intervals of the through holes 3 formed in the concentric circular groove portions 2 may be the same or different in each plate-shaped cold storage material. Good.

FIG. 2B shows a stacking method when the pitch of the through holes of the plate-shaped cool storage material to be stacked is different. In this case, if the pitches of the through holes of the adjacent plate-shaped regenerator materials are made different, most of the through holes are adjacent to each other, regardless of how they are stacked, as shown in FIG. The refrigerant gas does not overlap in the cold storage material, and the refrigerant gas flows through the groove portion 2 to the through hole portion 3 of the adjacent plate-shaped cold storage material. In this way, efficient heat exchange between the plate-shaped regenerator material and the refrigerant gas can be realized.

When the holes of the plate-shaped regenerator material are the same, as shown in FIG. 2C, adjacent plate-shaped regenerator materials are laminated so that the through-hole portions 3 do not overlap each other. In order to realize such an arrangement, an engaging portion that fits a part of the plate-shaped cold storage material may be provided. For example, a concave portion may be provided on the front surface side of the plate-shaped cold storage material, a convex portion having a corresponding shape may be formed on the bottom surface side, and the concave portion and the convex portion may be engaged when stacked.

When the heat conductivity of the plate-shaped cold storage material is high, high heat conduction occurs between adjacent plate-shaped cold storage materials, and it may be difficult to form an effective temperature distribution. When a magnetic material is used as the material of the plate-shaped cold storage material, the magnetic material generally has a low thermal conductivity, and therefore it is effective for limiting the thermal conductivity.

By using the plate-shaped regenerator material having the groove and the through hole, it is possible to secure a desired flow of the refrigerant gas and to increase the filling rate of the regenerator material to 70% or more. By using more regenerator material, the heat capacity of the regenerator as a whole can be increased and the refrigerating capacity can be improved.

When a material having a specific heat peak in a low temperature region such as a magnetic body is used, an effective refrigerating capacity can be realized by stacking a plurality of materials having different specific heat peak positions. Compared with the case of using the spherical cold storage material, even if different materials are used, it is not necessary to form a partition between different materials, the assembly is simplified, and the cold storage material is not mixed during use.

The shapes and distributions of the grooves and the through holes can be variously modified in addition to those described above. For example, the groove portions may be provided in a radial pattern, and further, a groove portion on a disk may be combined with the central portion and an annular groove portion may be combined with the periphery. Further, a groove portion which is not continuous and may be divided in the middle may be provided.

The cross-sectional shape of the groove portion is not limited to a rectangular shape, but may be a triangular shape, a semicircular shape, or a modification or combination thereof. Any configuration may be adopted as long as the refrigerant gas flows through the adjacent plate-shaped regenerator material and each part of the plate-shaped regenerator material can effectively exchange heat with the refrigerant gas passing therethrough.

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

[0040]

[Effect of device]

 The filling rate of the regenerator material in the regenerator can be improved. Further, even when a plurality of types of cold storage materials are used, it is possible to prevent mixing of a plurality of cold storage materials without providing a partition.

[Brief description of drawings]

FIG. 1 is a plan view and a cross-sectional view showing a configuration of a cold storage material used in a low temperature cool storage device according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing the configuration of the displacer filled with the cold storage material shown in FIG.

FIG. 3 is a schematic cross-sectional view showing a configuration of a GM cycle refrigerator according to a conventional technique.

[Explanation of symbols]

 1 Plate-shaped cold storage material 2 Groove part 3 Through hole part 4 Displacer 5 Cylinder 6 Cooling space 7 Opening (vent hole) 8 Lid material 9 Vent hole

Claims (4)

[Scope of utility model registration request] 1. A container (4) having vent holes (7, 9) at both ends and having a storage space inside, and a through hole portion (4) housed in the storage space of the container and formed of a cold storage material. 3) A plurality of plate-shaped bodies having a groove portion (2) continuous with the through hole portion, and a plurality of plate-like bodies arranged so that at least a part of projections of the through hole portion and the groove portion overlap each other when they are overlapped. Low temperature regenerator having the plate-shaped regenerator material (1). 2. The container (4) has a cylindrical shape having gas circulation holes (7, 9) at both ends, the plurality of plate-shaped cold storage materials (1) have a disk shape, and the groove (2). The low temperature regenerator according to claim 1, wherein is a concentric circular groove provided in each plate-shaped regenerator material. 3. The low temperature regenerator according to claim 2, wherein the through holes (3) are arranged so as not to substantially overlap between the adjacent plate-shaped regenerator materials (1). 4. The regenerator material is a magnetic material.
The low temperature regenerator according to any one of 3 above.