JP2563272Y2 - Low temperature regenerator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-temperature regenerator, and more particularly to a low-temperature regenerator used for a refrigerator using a refrigerant such as helium gas.

[0002]

2. Description of the Related Art As cryogenic refrigerators, there are a Gifford McMahon (GM) cycle refrigerator, a Solvay refrigerator, a Stirling refrigerator and the like. I have.

In the refrigeration cycle, the refrigerant gas passes through a regenerator before and after a heat absorbing step of adiabatically expanding a high-pressure refrigerant gas sent from a compressor, and at that time, exchanges heat with a regenerator material. The refrigerant gas has an absolute temperature of 10 to 20 ° K.
Helium gas that does not liquefy even in the vicinity is used.

FIG. 3 shows the structure of a conventional GM cycle refrigerator equipped with a regenerator. Reference numeral 10 denotes a compressor, which compresses helium gas as a refrigerant. The compressed helium gas is cooled by a gas cooler 11 and further cooled by an oil separator 1.
In step 2, oil mist and the like mixed in the refrigerant gas are removed.

The helium gas leaving the oil separator 12 is introduced into a cold head 20 having a built-in regenerator via a pipe 14 via an intake valve 13 for opening and closing a pipe passage. The helium gas of the refrigerant that has exited the cold head 20 passes through the exhaust valve 16 that opens and closes the pipe passage from the pipe 15, passes through the surge tank 17, becomes refrigerant gas at normal temperature and normal pressure, and returns to the inlet of the compressor 10. By repeating the above cycle, the tip of the cold head 20 is cooled and reaches a very 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 disposed inside a cylinder 21 as an outer container. The displacer 22 is filled with a cold storage material 23 in its internal space.

[0007] The regenerator material 23 has a large heat capacity and a material and structure with high heat exchange efficiency, and it is necessary to allow the refrigerant gas to pass through the inside. For this reason, a copper alloy mesh is laminated or lead particles having a uniform particle size are filled. 24 and 25 are passages for the refrigerant gas to enter and exit the cold storage 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 a top dead center and a bottom dead center. The top dead center is a point at which the volume of the lower expansion chamber 28 is minimized,
That is, the point at which the displacer has moved to the bottom in the figure. FIG. 2 shows a state in which the displacer 22 is located substantially 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 an expansion chamber 28 for generating freezing is provided.
When the refrigerant gas flows in and out, the refrigerant gas is sealed so as not to move through the gap between the displacer 22 and the outer container 21.

Next, the GM refrigeration cycle will be described. First, the intake valve 13 is gradually opened with the exhaust valve 16 closed with the displacer 22 at the top dead center position. Helium refrigerant gas, which has become high pressure in the compressor 10, passes through the intake valve 13 and the pipe 14 and passes through the cold head 2.
0 is introduced.

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 passes through the cold storage material 2.
Pass 3 At that time, the refrigerant gas exchanges heat with the cold storage material 23, heat is taken by the cold storage material 23, and reaches the expansion chamber 28 through the passage 25.

Next, when the intake valve 13 is closed and the exhaust valve 16 is gradually opened while the displacer 22 is at the bottom dead center, the high-pressure refrigerant gas is brought into pressure with the inlet side of the compressor 10. Due to the difference, adiabatic expansion occurs at a stretch and the temperature decreases, and the refrigerant gas in the expansion chamber 28 absorbs heat and cools the surroundings through the flange 29.

When the displacer 22 is further lowered from the bottom dead center toward the top dead center, the cooled refrigerant gas in the expansion chamber 28 passes through the passage 25, the cold storage material 23, the passage 24, the pipe 15,
It flows to the exhaust valve 16, the surge 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 pulsating refrigerant gas is directly supplied to the displacer without passing through a valve. The displacer reciprocates out of phase with the pulsating refrigerant gas to implement a 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 cryogenic regenerators. When the spherical particles are used as a cold storage material, the filling rate is about 60% even if the particles are filled using vibration or the like.

When cryogenic temperatures are reached, many materials sharply reduce their specific heat. For example, when cooling a refrigerant gas from about 30K to about 4K, it is desired to use a regenerator material having a high specific heat in the temperature range of the gas in contact.

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

[0018]

When a limited space of a regenerator is to be filled with a regenerative material having a higher cooling capacity, it is desired to fill as much as possible. The filling rate in the case of using a regenerator material of spherical particles is limited to about 60% as described above. When it is intended to fill more regenerator material, it is desired that the regenerator material has a shape other than spherical particles.

In the case where several kinds of materials are used as a cold storage material, a partition is required if a cold storage material of spherical particles is used. The use of the partition not only complicates the assembly, but also breaks the partition during operation, causing the regenerative material to mix and lowering the reliability.

An object of the present invention is to provide a high-efficiency 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 has high reliability.

[0021]

The low-temperature regenerator according to the present invention comprises:
Both ends have a vent, and a cylindrical containers <br/> unit having a housing space therein, is accommodated in the housing space of the container, is formed by the cold storage material, contiguous to the through hole and the through hole a plurality of disc-shaped cold accumulating material having a plurality of concentric <br/> groove, adjacent
When the disc-shaped cold storage material is overlaid, one through hole and the other
There at least partially overlap each other if the projection of the groove of both
Through holes of the person and a plurality of disc-shaped cold accumulating material is arranged so as not to overlap substantially.

[0022]

By using a plurality of plate-like 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 a groove and a through hole continuous with the groove, 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 with each other, and a gas passage is secured. Therefore, a high cooling function can be realized.

[0024]

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

The plate-like cold storage material 1 has a disk shape, and has a plurality of concentric grooves 2 formed on the surface thereof. Each groove 2
Inside, through holes 3 reaching from the bottom surface of the groove to the back surface are formed in one row . The cold storage material 1 is produced by sintering a magnetic material containing, for example, a rare earth element or a transition metal.

After the thin disk-shaped cold storage material 1 is formed by sintering, at least one surface thereof is made flat.
With the flat flat surface facing downward, concentric thin grooves 2 are formed in the plate-like cold storage material 1.

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

FIG. 2 shows the structure of the displacer. FIG.
FIG. 2A is a schematic cross-sectional view showing a state in which a cool storage material is filled into a displacer, and FIGS. 2B and 2C are schematic cross-sectional views showing how a plate-like cool storage material in the displacer is stacked. .

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

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

Although the plate-like cold storage material has the structure shown in FIG. 1, the interval between the through holes 3 formed in the concentric grooves 2 is different even if the plate-like cold storage material is the same. Is also good.

FIG. 2B shows how to stack the plate-shaped cold storage materials when the pitches of the through holes are different. In this case, if the pitches of the through-holes of the adjacent plate-like cold storage materials are made different, most of the through-holes will be adjacent to the plate-like cold storage as shown in FIG. The refrigerant gas does not overlap, and the refrigerant gas flows through the groove portion 2 to the through-hole portion 3 of the adjacent plate-like cold storage material. In this way, efficient heat exchange between the plate-like cold storage material and the refrigerant gas can be realized.

When the arrangement of the holes in the plate-like cold storage material is the same,
As shown in FIG. 2 (C), adjacent plate-like cold storage materials are laminated so that the through-holes 3 do not overlap. In order to realize such an arrangement, an engaging portion that fits into a part of the plate-like cold storage material may be provided. For example, a concave portion may be provided on the front surface side of the plate-like cold storage material, a convex portion having a shape corresponding to the bottom surface side may be formed, and the concave portion and the convex portion may be engaged when laminating.

When the thermal conductivity of the plate-like cold storage material is high, high heat conduction occurs between adjacent plate-like 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-like cold storage material, the magnetic material generally has a low thermal conductivity, which is effective for restricting the heat conduction.

By using a plate-shaped regenerator having a groove and a through-hole, it is possible to secure a desired flow of the refrigerant gas and to increase the filling rate of the regenerator to 70% or more. By using more regenerative materials, it is possible to increase the heat capacity of the entire regenerator and improve the refrigerating capacity.

When a material having a specific heat peak in a low temperature region such as a magnetic material is used, an effective refrigerating capacity can be realized by stacking a plurality of materials having different specific heat peak positions. Compared to using spherical cold storage material,
Even if different kinds of materials are used, there is no need to form a partition between the different kinds of materials, the assembling is simplified, and there is no mixing of the cold storage material during use.

The shapes and distributions of the grooves and the through-holes can be variously changed in addition to those described above. For example, the grooves may be provided radially, and a groove on a disk may be combined at the center or an annular groove may be combined at the periphery. Further, a groove portion which is not continuous but may be divided on the way may be provided.

The cross-sectional shape of the groove may be not only rectangular but also triangular, semicircular, or a modification or combination thereof. Refrigerant gas flows through the adjacent plate-like cold storage material,
Any configuration may be used as long as the configuration allows effective heat exchange with the refrigerant gas passing through the respective portions of the plate-like cold storage material.

The present invention has been described with reference to the embodiment.
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.

[0040]

According to the invention, the filling rate of the cold storage material in the cold storage can be improved. In addition, even when a plurality of types of cold storage materials are used, mixing of a plurality of cold storage materials can be prevented without providing a partition.

[Brief description of the 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 regenerator according to an embodiment of the present invention.

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

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

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 plate-like cold storage material 2 groove 3 through hole 4 displacer 5 cylinder 6 cooling space 7 opening (vent) 8 lid 9 vent

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-1-142250 (JP, A) JP-A-2-130355 (JP, A) JP-A-4-268166 (JP, A) 169379 (JP, U) Actual opening Sho 62-63590 (JP, U)

Claims (4)

(57) [Scope of request for utility model registration] 1. A cylindrical container (4) having ventilation holes (7, 9) at both ends and having a housing space therein; a through-hole housed in the housing space of the container and formed of a cold storage material; Concentric circles continuous with the part (3) and the through-hole part
A plurality of disc-shaped regenerators having a groove- like portion (2),
When superimposed adjacent disc-shaped cold accumulating material (1), at least a portion of one of <br/> through-hole portion and the other groove of the projection is had <br/> overlap if one another, both the through holes (3) is almost non-overlapping
A plurality of disc-shaped cold accumulating material which is disposed so as have (1) a low-temperature regenerator with. 2. The method according to claim 1, wherein the cold storage material is a magnetic material.
Onboard low-temperature regenerator. 3. The disk-shaped cold storage material is positioned in a circumferential direction.
The low-temperature cold storage according to claim 1 or 2, further comprising:
vessel. 4. The through-hole portion is formed in each of the concentric grooves.
4. The method according to claim 1, wherein each of the rows is formed in a line.
Onboard low-temperature regenerator.