JP2002286311A - Cryogenic refrigerator - Google Patents

Abstract

(57) [Summary] (Modifications) [Problem] To prevent a gap between a cylinder and a lid or a sorting member from increasing even when the temperature of a regenerator falls to a very low temperature level, and to prevent the refrigerator from operating during operation. The present invention suppresses the occurrence of drift of the refrigerant gas in the regenerator, increases the heat exchange efficiency between the regenerator material and the gas, and improves the cooling performance of the cryogenic refrigerator. A regenerator (3) in a cryogenic refrigerator includes a cylinder (34), lids (35H, 35L) for closing the ends thereof, and three types of granular cold storage materials (36H to 36L) filled in a layer inside the cylinder (34). And separating members 37H and 37L arranged at the boundary between the different types of cold storage materials 36H to 36L, and the lids 35H and 35L of the regenerator 3 and the respective separating members 37H and 37L are negative with respect to temperature. And a lid 35H, 35L during operation of the refrigerator.
The outer diameters of the partition members 37H and 37L are relatively increased with respect to the cylinder 34.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic refrigerator that generates cold heat (cold) by repeatedly compressing and expanding a refrigerant gas, and more particularly, to a structure of a regenerator (regenerative heat exchanger). Belongs to.

[0002]

2. Description of the Related Art A cryogenic refrigerator of this type has been generally known. For example, a compressor for compressing a refrigerant gas such as helium gas and a high-pressure refrigerant gas from the compressor and a compressor are returned. A switching valve for switching low-pressure refrigerant gas,
A regenerator connected to the switching valve for accumulating cold heat when the refrigerant gas expands, and one or more cooling stages connected to the regenerator; The compression wave and the expansion are repeated by the pressure wave of the refrigerant gas added through the vessel to generate cold heat.

[0003] As the regenerator, for example, a regenerator is used in which a granular regenerative material is filled in a cylinder, and after filling, the end of the cylinder is closed by a lid through which refrigerant gas can flow. And one end of the cylinder in the regenerator is
A cryogenic level (e.g., 4.
The low-temperature end where the temperature falls to 2K), and the other end becomes a high-temperature end having a higher temperature (for example, 50K) than the low-temperature end.

On the other hand, as the cold storage material, a magnetic cold storage material having a characteristic of having a sufficient heat capacity in a temperature range at an extremely low temperature level is used. This magnetic regenerator material has a specific temperature at which the specific heat is maximum, and the temperature at which the specific heat peaks differs for each type of regenerative material. Therefore, when the same type of cold storage material having the maximum specific heat in the temperature range of, for example, the low-temperature end (or high-temperature end) side of the cylinder in the regenerator is filled over the entire regenerator, the high-temperature end Part side (or low temperature end side)
In this temperature range, the temperature deviates from the peak temperature of the specific heat of the cold storage material, and the cold storage efficiency of the cold storage device becomes insufficient.

[0005]

Therefore, a plurality of types of cold storage materials, each having a different specific heat peak temperature, are used, and the plurality of types of cold storage materials are filled in layers in the regenerator to correspond to different temperature ranges. In addition to disposing them, at the boundary between these different types of cold storage materials, if a separating member capable of flowing refrigerant gas is arranged so that both types of cold storage materials do not mix with each other, the specific heat of each type of cold storage material is effective. To increase the cool storage efficiency of the cool storage device.

When manufacturing a regenerator having such a partitioning member or a regenerator without such a partitioning member, one of the lids is fitted into one end of the cylinder and then the lid is used as a bottom wall for the regenerator material. For those having a sorting member, after the fitting of the sorting member is filled with another type of cold storage material, and finally, the other end of the cylinder is fitted with the other lid, thereby storing the cold storage material. A vessel is manufactured.

In this case, the gap generated between the inner peripheral surface of the cylinder and each outer peripheral portion of the lid or the partitioning member for inserting the lid or the partitioning member into the cylinder is set to a minimum necessary. However, when manufacturing the regenerator at room temperature, even if the gap between the inner peripheral surface of the cylinder and the outer peripheral portion of the lid or the partitioning member is set to a minimum, the regenerator is operated at extremely low temperature during operation of the refrigerator. When the temperature drops to the level, it is inevitable that the above-mentioned gap increases accordingly. For this reason, the refrigerant gas, which should originally flow through the lid and the separating member, flows through the increased gap, and the gas flow inside the regenerator and inside and outside the regenerator becomes deviated and the gas flow rate increases. Is not uniform (see FIG. 5), and as a result, there arises a problem that the heat exchange efficiency between the cold storage material and the gas is reduced and the cooling performance of the refrigerator is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to specify a material of a lid and a partition member to be inserted into a cylinder of a regenerator, as described above, to thereby determine the temperature of the regenerator. Even if the temperature drops to a cryogenic level, the gap between the lid and the sorting member and the cylinder is prevented from increasing, and the occurrence of drift of the refrigerant gas in the regenerator during operation of the refrigerator is suppressed. It is an object of the present invention to improve the efficiency of heat exchange between gas and gas and improve the cooling performance of a cryogenic refrigerator.

[0009]

In order to achieve the above object, according to the present invention, the lid and / or the partition member of the regenerator are made of a material having a negative expansion coefficient which expands as the temperature decreases.

Specifically, in the first aspect of the present invention, the pressure wave generating means (24) for generating a pressure wave of the refrigerant gas, and the pressure wave of the refrigerant gas by the pressure wave generating means (24) is used to generate the refrigerant gas. A cryogenic refrigerator having at least one cooling stage (9, 11) for generating cold heat by repeating compression and expansion, and a regenerator (2, 3) for storing cold heat during expansion of the refrigerant gas. And

The regenerator (3) is inserted into a cylinder (34) and an end of the cylinder (34).
A lid (35H, 35L) through which the refrigerant gas can flow, and a cylinder (34) closed by the lid (35H, 35L)
And a regenerator material (36H to 36L) filled in the inside of the container, and the lid (35H, 35L) is made of a material having a zero or negative expansion coefficient with respect to temperature.

According to a second aspect of the present invention, in the cryogenic refrigerator similar to the premise of the first aspect of the invention, the regenerator (3) includes a cylinder (34) and the cylinder (34).
The lid (35) is inserted into the end of the
H, 35L) and at least two kinds of cold storage materials (36H to 36L) filled in layers in the axial direction of the cylinder (34) inside the cylinder (34) closed by the lid (35H, 35L). ), And a partition member (37H, 37L) which is inserted into the cylinder (34) so as to be located at a boundary between the different types of cold storage materials (36H to 36L) and through which refrigerant gas can flow. The sorting member (37
H, 37L) is made of a material having a zero or negative expansion coefficient with respect to temperature.

According to a third aspect of the present invention, in the cryogenic refrigerator according to the second aspect, the lid (3) of the regenerator (3) is provided.
5H, 35L) is made of a material having a zero or negative expansion coefficient with respect to temperature.

According to the constitution of each of these inventions, the lid (35H, 35L) and / or the partition member (37H, 37L) of the regenerator (3) are made of a material having a zero or negative expansion coefficient with respect to temperature. So these lids (35H, 35L)
The partition members (37H, 37L) expand when their temperature decreases to a cryogenic level during operation of the refrigerator, and their outer diameters increase relatively to the cylinder (34).
For this reason, when manufacturing the regenerator (3) at room temperature, the lid (3)
5H, 35L) and the outer diameter of the sorting members (37H, 37L) are smaller than the inner diameter of the cylinder (34) so as to have a clearance required for insertion into the cylinder (34). The refrigerator enters the operating state, and its lid (35)
H, 35L) and the partition members (37H, 37L) drop in temperature, the expansion of the lids (35H, 35L) and the partition members (37H, 37L) causes the outer peripheral surface and the inner peripheral surface of the cylinder (34) to move. The gap between them becomes sufficiently small or zero (0). As a result, no drift of the refrigerant gas occurs between the inside and the outside of the regenerator (3) or inside the regenerator, the flow distribution of the refrigerant gas becomes uniform, and the cooling performance of the refrigerator can be improved and maintained.

According to a fourth aspect of the present invention, in the cryogenic refrigerator according to the second aspect of the present invention, when a plurality of sorting members (37H, 37L) are provided, the temperature of the plurality of sorting members (37H, 37L) is increased. Is made different depending on the cooling temperature position of the regenerator (3).

According to a fifth aspect of the present invention, in the cryogenic refrigerator according to the first or third aspect of the present invention, the expansion rates of the lids (35H, 35L) located at both ends of the cylinder (34) with respect to the temperature are determined. Make them different.

In this case, the lid (35H, 35L) and the partitioning member (37H, 35H) can be selected according to the temperature range in the regenerator (3).
37L), the lid (35H, 35L) and the separating member (37H, 37L) during operation of the refrigerator.
L) and the gap between the cylinder (34) can be kept substantially constant.

According to a sixth aspect of the present invention, the pressure wave generating means (24) includes a compressor (16) for compressing the refrigerant gas, a high-pressure refrigerant gas from the compressor (16) and the compressor (1).
And a switching valve (17) for switching the low-pressure refrigerant gas returning to 6). Thus, a desirable pressure wave generating means (24) can be embodied.

[0019]

FIG. 4 shows an entire configuration of a cryogenic refrigerator (R) according to an embodiment of the present invention.
Comprises a two-stage pulse tube refrigerator using, for example, helium gas as a refrigerant gas. (1) is a vacuum chamber in which the inside is kept in a vacuum adiabatic state, in which a first and second stage regenerators (2, 3) composed of regenerative heat exchangers, and first and second stages are stored. Two-stage pulse tubes (5, 6) are accommodated, and these are suspended and supported on the upper wall of the vacuum chamber (1) in an insulated state.

Each of the regenerators (2, 3) is disposed substantially at the center of the vacuum tank (1), and the upper end of the first-stage regenerator (2) is located outside the upper wall of the vacuum tank (1). At the high temperature end (normal temperature end). The outer diameter of the first-stage regenerator (2) (the outer diameter of a cylinder (34) described later in detail) is larger than that of the second-stage regenerator (3), and both regenerators (2, 3) are mutually connected. The refrigerant gas is communicated so as to be able to flow.

The lower end of the first stage regenerator (2)
The first stage cooling stage (9), whose temperature drops to a cryogenic level (for example, 50K or less) due to the expansion of the refrigerant gas in the expansion space inside the first stage pulse tube (5), and the second stage regenerator (3) The lower end of the second stage pulse tube (6)
Due to the expansion of the refrigerant gas in the internal expansion space, a temperature level lower than that of the first cooling stage (9) (for example, 4.2K)
The first cooling stage (9) is connected to the entire second stage cooling stage (11) and the low temperature of the second stage regenerator (3). A shield part (14) for radiation shielding the end from the surroundings, and a cooling object (not shown) are in contact with the second cooling stage (11) so as to be able to conduct heat.

On the other hand, the first-stage and second-stage pulse tubes (5, 6) are respectively arranged at different peripheral positions of the vacuum chamber (1), and the upper end of each pulse tube (5, 6) is placed in a vacuum chamber. (1) It is located outside the upper wall and is a hot end. These pulse tubes (5, 6) reciprocate the virtual piston of the refrigerant gas inside by the pressure wave of the refrigerant gas by the pressure wave generating means (24) described later, and the refrigerant gas is cooled by the cooling stage (9, 11). The low-temperature end of the lower end of the first-stage pulse tube (5) and the lower end of the first-stage regenerator (2) are connected to the first-stage communication pipe by repeating the compression and expansion of By (12), the refrigerant gas is communicated so as to be able to flow. The low-temperature end of the lower end of the second-stage pulse tube (6) and the lower end of the second-stage regenerator (3) are connected by a second-stage communication tube (13) so that refrigerant gas can flow.

One end (lower end) of a gas supply / discharge pipe (15) is connected to the high temperature end of the first stage regenerator (2), and the other end (upper end) of the gas supply / discharge pipe (15). Part) is provided with a rotary valve (17) to a compressor (16) that compresses a refrigerant gas such as helium and constantly generates a high-pressure refrigerant gas.
Connected through. This rotary valve (17)
Are a fixed valve body (18) and a rotary valve body (19) which are in contact with each other.
A supply / discharge port (20) which is always in communication with the gas supply / discharge pipe (15) (the high-temperature end of the first-stage regenerator (2)) on a contact surface of the fixed valve body (18); A low pressure port (21) constantly communicating with the suction portion of (16), and a high pressure port (22) constantly communicating with the discharge portion of the compressor (16) on the contact surface of the rotary valve body (19). The rotary valve element (19) is relatively rotated with respect to the fixed valve element (18), and the discharge or suction part of the compressor (16) is connected to the supply / discharge port (20). When the high pressure port (22) of the rotary valve body (19) is connected to the supply / discharge port (20) of the fixed valve body (18) by switching and communicating with each other,
The high-pressure refrigerant gas from the compressor (16) is supplied to the high-pressure port (2
2) or regenerator (2, 3) via supply / discharge port (20)
And the pulse tubes (5, 6), while the rotary valve body (1
The communication part (23) is rotated by the rotation of 9) to supply and discharge the port (2).
0), the refrigerant gas is supplied from the pulse tubes (5, 6) and the regenerators (2, 3) to the compressor via the supply / discharge port (20), the communication part (23), and the low pressure port (21). It returns to the suction part of (16). Therefore,
The compressor (16) and the rotary valve (17) constitute a pressure wave generating means (24) for generating a pressure wave of the refrigerant gas in a predetermined cycle.

At the high-temperature end of each of the pulse tubes (5, 6), the phase of the refrigerant gas pressure with respect to the high-temperature end is controlled to reciprocate the virtual piston of the refrigerant gas in the pulse tubes (5, 6). Phase control means (26a, 26b) for producing a phase difference with respect to switching of supply / discharge of high-pressure or low-pressure refrigerant gas by the rotary valve (17) is provided.

Each of the phase control means (26a, 26b)
Are connected to the high-temperature end of each pulse tube (5, 6) by a pipe (27a,
A buffer space (not shown) communicated via the buffer tank (28a, 28b) is provided inside the pipe (27a, 27b). Adjustment valves (29a, 29b) are connected. This flow control valve (29a, 29b)
(27) and the high-temperature end of each pulse tube (5, 6).
a, 27b) have branch pipes (30a, 30b) respectively.
Is branched and connected to each branch pipe (30a, 3a).
0b) is connected to a gas supply / discharge pipe (15) between the first-stage regenerator (2) and the rotary valve (17), and is fixed in the middle of the branch pipe (30a, 30b). A second flow control valve (31a, 31b) having an opening is connected. Each of the flow control valves (29a, 29)
b, 31a, 31b) are pipes (27a, 27b, 30).
a, 30b) has a function of giving a flow resistance to the refrigerant gas flowing in the inside. Then, the pressure wave of the refrigerant gas generated by the rotary valve (17) is transmitted to the second flow control valve (31a, 3a).
Each pulse tube (5, 6) while applying flow resistance in 1b)
And supplying and discharging the refrigerant gas from the high temperature end to the buffer space in the buffer tanks (28a, 28b) while imparting flow resistance by the first flow control valves (29a, 29b). And the pulse tube (5, 6)
The virtual piston of the refrigerant gas is reciprocated in the pulse tube (5, 6) by controlling the phase of the refrigerant gas pressure with respect to the high-temperature end of the cooling stage (9, 11). The refrigerant gas is expanded in the expansion space to generate cryogenic heat at an extremely low temperature in the cooling stage (9, 11). The phase control means (26
a, 26b) are buffer tanks (28a, 28a).
b), the first flow control valve (29a, 29b) and the second
It is constituted by a flow control valve (31a, 31b).

In each regenerator (2, 3), the rotary valve (17) is switched so that the gas supply / discharge pipe (15) communicates with the suction part (low pressure side) of the compressor (16). , Refrigerant gas from each corresponding pulse tube (5, 6) is supplied to the corresponding regenerator (2, 3) and gas supply / discharge pipe (1).
When the refrigerant gas is returned to the suction section of the compressor (16) via 5), the cold heat of the refrigerant gas generated in the expansion space in the cooling stage (9, 11) is stored in a cold storage material described later by heat exchange, Conversely, the rotary valve (1) is connected so that the gas supply / discharge pipe (15) communicates with the discharge section (high pressure side) of the compressor (16).
7) is switched so that when the high-pressure refrigerant gas is supplied to each pulse tube (5, 6) via the gas supply / discharge pipe (15) and the corresponding regenerator (2, 3), the refrigerant gas In this case, the stored cold heat is given by heat exchange.

Although not shown, the first-stage regenerator (2) includes a plurality of cold storage materials obtained by punching a copper alloy or stainless steel wire net into a circular shape inside a cylindrical cylinder made of, for example, stainless steel. It is configured by laminating and filling.

On the other hand, the second stage regenerator (3)
As shown in FIG. 7, a cylindrical cylinder (34) made of, for example, stainless steel is inserted into and locked at both ends of the cylinder (34), and the high-temperature side and the low-temperature side are closed respectively. Each lid (35H, 35L) is provided. As shown in FIG. 2 by enlarging the low-temperature side lid (35L) (the high-temperature side lid (35H) has the same configuration), each of the lids (35H, 35L) has a bottom (35L).
a) and a side wall (35b) extending cylindrically from the periphery of the bottom (35a), at least the bottom (35a).
Is composed of a perforated plate having a large number of penetrating circular pores (not shown) formed thereon, and a metal mesh (not shown) made of copper alloy is adhered to the perforated plate. Part (35
H, 35L) sends the refrigerant gas inside and outside the cylinder (34),
That is, in the low temperature side lid (35L), the cylinder (3
4) between the interior and the expansion space, and the high temperature side lid (35).
In the case of H), it is possible to flow between the inside of the cylinder (34) and the expansion space or the gas supply / discharge pipe (15).

In the cylinder (34) closed by the lids (35H, 35L), three types of cold storage materials (36H, 36M, 36) of a high temperature side, a medium temperature side, and a low temperature side are provided.
L) are arranged in layers in the axial direction of the cylinder (34). Each of the cold storage materials (36H to 36L) is made of, for example, a granular lead alloy or a magnetic cold storage material having a particle size of about 0.5 mm, and has a different specific heat peak temperature.
The high-temperature side regenerator (36H) has a peak specific heat higher than that of the medium-temperature regenerator (36M), and the medium-temperature side regenerator (36M) has a low specific heat peak temperature of the low-temperature side regenerator (3M).
6L).

Further, in the cylinder (34), two dividing members (37H, 37L) on the high temperature side and the low temperature side are arranged so as to be located at the boundaries between the three different types of cold storage materials (36H to 36L). It is fitted and locked. Each of the partition members (37H, 37L) is illustrated as an enlarged example of the low-temperature partition member (37L) in FIG. 1 (the high-temperature partition member (37H) has the same configuration). 35H, 35L), the bottom (37a) and the side wall (3) extending cylindrically from the periphery of the bottom (37a).
7b), at least a bottom portion (37a) of which is constituted by a perforated plate having a large number of circular pores (not shown) formed therethrough. A copper alloy wire mesh (not shown) is attached to this perforated plate. The partitioning member (37
H, 37L) can flow the refrigerant gas in the spaces on both sides thereof.

When the second stage regenerator (2) is manufactured, a low-temperature side lid (35L) is connected to a side wall (35b) of a cylinder (34) from one end which is a low-temperature end thereof. Place and insert so that it faces the end side (hot end side), then
After the low-temperature side cold storage material (36L) is filled into the cylinder (34) from the other end opening which is the high-temperature end so as to be stacked on the low-temperature side lid (35L), the other end which becomes the same high-temperature end From the opening into the cylinder (34), the low temperature side sorting member (37
L) is oriented in the same direction as the low-temperature side lid (35L) and is fitted so as to be in contact with the low-temperature side cold storage material (36L). Similarly, the medium-temperature side cold storage material (36M) is filled, and the high-temperature side sorting member (37H) After inserting the high temperature side cold storage material (36H) in order, the high temperature side lid (35H) is attached to the other end opening of the cylinder (34) by the side wall (35b) at one end side (low temperature end). ), That is, in the opposite direction to the low temperature side lid (35L) and the sorting members (37H, 37L).

The lids (35H, 35L) and the dividing members (37H, 37L) are made of a material having zero (0) or a negative expansion coefficient with respect to temperature. Further, two lids (35H, 35L) and a separating member (3
7H, 37L) differs depending on the cooling temperature position of the regenerator (3). When the magnitudes of the expansion rates in the regenerator (3) are arranged, the low temperature side lid (35L)> low temperature In this order, the side partition member (37L)> the high temperature side partition member (37H)> the high temperature side lid (35H).

Specifically, the lid (35H, 35L)
The material of the sorting members (37H, 37L) is, for example, Dyneema fiber FRP (trade name of Toyobo Co., Ltd.), aramid fiber FRP, carbon fiber FRP, or the like, all of which have negative expansion in the fiber length direction. Having a rate. However,
These fibers have a positive coefficient of expansion in the radial direction orthogonal to their length direction, so that the length direction of the fibers is changed to the lid (35H,
35L) and the sorting members (37H, 37L) need to be arranged along the radial direction. The expansion rate with respect to temperature is changed by changing the content of these fibers, and the expansion rate increases as the fiber content increases.

Next, the cryogenic refrigerator (R) of the above embodiment is described.
The operation of will be described. During the operation of the refrigerator (R), the rotation of the rotary valve (17) is switched, and by the switching of the rotary valve (17), the high-pressure refrigerant gas discharged from the compressor (16) returns to the compressor (16). The low pressure refrigerant gas is alternately switched to generate a pressure wave of the refrigerant gas in a predetermined cycle, and the pressure wave is generated by the gas supply / discharge pipe (15),
The first and second stage regenerators (2, 3) and the communication pipe (1
2, 13), the first and second stage pulse tubes (5, 5)
6) is transmitted to the inside from the low temperature end. Further, the phase of the refrigerant gas pressure with respect to the high-temperature end of each pulse tube (5, 6) is controlled by the phase control means (26), and the virtual piston of the refrigerant gas in each pulse tube (5, 6) is set to a predetermined position. Reciprocates periodically. Due to the reciprocating motion of the virtual piston of the refrigerant gas, the refrigerant gas expands in the expansion space in the cooling stage (9, 11) below each regenerator (2, 3), and the expansion of the refrigerant gas generates cold heat. The first cooling stage (9) is at a cryogenic level, and the second cooling stage (1)
1) is cooled to a cryogenic level lower than that of the first cooling stage (9), and its second cooling stage (1) is cooled.
The cooling object arranged so as to be able to conduct heat in 1) is cooled and held at the same cryogenic level set temperature.

During this time, the rotary valve (17) is switched so that the gas supply / discharge pipe (15) communicates with the suction section of the compressor (16), and the refrigerant gas is cooled and stored from each pulse pipe (5, 6). When the refrigerant gas is returned to the suction part of the compressor (16) through the coolers (2, 3), the refrigerant gas is stored in the cold storage material inside the cylinders of the regenerators (2, 3). Specifically, in the second stage regenerator (3), the refrigerant gas enters the cylinder (34) from the low temperature side lid (35L), and the low temperature side cold storage material (36L) in the cylinder (34). Between the low-temperature side partition member (37L) and the medium-temperature side cold storage material (36L).
M), and after passing through the space between the high-temperature side sorting member (37H) and the high-temperature side cold storage material (36H), it flows out of the cylinder (34) from the high-temperature side lid (35H), and the above-mentioned cold storage material ( While passing through the space between 36H-36L), the cold heat of the refrigerant gas is stored in the cold storage material (36H-36L) by heat exchange.

On the other hand, on the other hand, the rotary valve (1) is connected so that the gas supply / discharge pipe (15) communicates with the discharge section of the compressor (16).
7) is switched, and when high-pressure refrigerant gas is supplied to each pulse tube (5, 6), contrary to the above cold storage,
The refrigerant gas is supplied with the cold stored in the regenerators (2, 3) by heat exchange, and in the second stage regenerator (3), the refrigerant gas is transferred from the high temperature side lid (35H) to the cylinder (34). And the high temperature side cold storage material (36H) in the cylinder (34)
After passing through the space between the high-temperature side partition member (37H) and the medium-temperature side cold storage material (36M), and the space between the low-temperature side partition member (37L) and the low-temperature side cold storage material (36L). 35L), flows out of the cylinder (34), and passes through the space between the cold storage materials (36H to 36L), whereby the stored cold heat is given by heat exchange.

In the second-stage regenerator (3), three types of regenerative materials (36H) having different temperatures at which specific heat peaks are obtained.
To 36L) are filled in a layered manner in the cylinder (34) so as to correspond to the temperature range where each specific heat peaks, and both types of cold storage materials are provided at the boundary between these different types of cold storage materials (36H to 36L). (36H-36L) so that the refrigerant gas can be prevented from being mixed with each other.
7L), each type of cold storage material (36H
To 36 L) can be used effectively to increase the cool storage efficiency of the cool storage device (3).

The lid (35H, 35L) and the partitioning members (37H, 37L) in the second stage regenerator (3).
Are made of a material having a zero or negative expansion coefficient with respect to the temperature, so that these lids (35H, 35L) and the separating member (37
H, 37L), even when the temperature of the refrigerator (R) decreases to a cryogenic level during operation of the refrigerator (R), the respective outer diameters increase relatively to the cylinder (34). For this reason, at the time of manufacturing the regenerator (3) at room temperature, the lid (35H, 35L) and the partitioning members (37H, 37L) can be inserted into the cylinder (34) in order to enable the lid (35H, 35L) to be inserted into the cylinder (34). , 37b) and the inner wall surface of the cylinder (34), the outer diameter of the side wall portions (35b, 37b) is set smaller than the inner diameter of the cylinder (34) so that a gap necessary for insertion is created. However, when the refrigerator (R) is in the operating state, the lid (35H, 35H)
L) and the expansion of the partitioning members (37H, 37L) due to the temperature drop, the gap between the outer peripheral surface of the side wall (35b, 37b) and the inner peripheral surface of the cylinder (34) becomes sufficiently small or zero (0). The outer peripheral surface of the side wall (35b, 37b) and the inner peripheral surface of the cylinder (34) are substantially in close contact. as a result,
As shown in FIG. 5, the gap (d) between the outer peripheral surface of the side wall (35b) of the sorting member (37H, 37L) (or the side wall (37b) of the lid (35H, 35L)) and the inner peripheral surface of the cylinder (34). ) Becomes large, the flow of the refrigerant gas through the gap (d) is suppressed or prevented, and the refrigerant gas passes only through the pores at the bottom (35a) (or (37a)). Thereby, the drift of the refrigerant gas does not occur between and inside or inside the regenerator (3), the flow rate distribution of the refrigerant gas becomes uniform, and the cooling performance of the refrigerator (R) can be improved and maintained.

In addition, the two lids (35H, 35H)
L) and the partitioning members (37H, 37L) have different expansion rates depending on the cooling temperature position of the regenerator (3), and the lid (35L) and the separating member (37) on the low-temperature side of the regenerator (3). 37L) is higher than the expansion rates of the lid (35H) and the sorting member (37H) on the high-temperature side, respectively. 35L) and sorting members (37H,
37L), the gap between the cylinder (34) and the lid (35H, 35L) or the partitioning members (37H, 37L) during operation of the refrigerator (R) is made approximately corresponding to the expansion coefficient with respect to the temperature of the refrigerator (R). Can be kept constant.

In the above embodiment, the compressor (16) for compressing the refrigerant gas and the rotary valve (17) for switching between the high-pressure refrigerant gas from the compressor (16) and the low-pressure refrigerant gas returning to the compressor (16). ) And pressure wave generating means (2)
Although 4) is configured, a reciprocating piston type compressor that periodically compresses refrigerant gas by reciprocating a piston in a cylinder may be used.

In the above embodiment, the lids (35H, 35L) and the separating members (37) of the second stage regenerator (3) are used.
H, 37L) is made of a material having a zero or negative expansion coefficient with respect to temperature, but a material selected from these materials may be made of the same material. In this case, it is preferable that the lid (35L) and the partitioning member (37L) on the lower temperature side than on the higher temperature side are made of a material having a negative coefficient of expansion.

In the above embodiment, three kinds of cold storage materials (36H to 36L) are used.
More than one kind of cold storage material can be used. However, when one kind of cold storage material is used, the sorting member is unnecessary,
Only the lid (35H, 35L) may be made of a material having a negative coefficient of expansion.

In the above embodiment, the cryogenic refrigerator (R) comprises a two-stage pulse tube refrigerator.
INDUSTRIAL APPLICABILITY The present invention is applicable to a cryogenic refrigerator including one or three or more stages of pulse tube refrigerators, and further includes a Stirling refrigerator including a displacer type expander that reciprocates a displacer in a cylinder, and a Gifford McMahon. The present invention can be applied to a regenerator such as a GM refrigerator having a cycle.

[0044]

As described above, according to the first aspect of the present invention, the pressure wave of the refrigerant gas is generated by the pressure wave generating means, and the compression and expansion of the refrigerant gas are repeated by the pressure wave of the refrigerant gas to generate cold heat. In a cryogenic refrigerator including at least one cooling stage to be generated and a regenerator storing cold heat when the refrigerant gas expands, the regenerator is configured to close an end of a cylinder so that refrigerant gas can flow therethrough. And a cold storage material filled inside the cylinder, and the lid thereof is
It consisted of a material having a zero or negative expansion coefficient with respect to temperature.
According to the second aspect of the present invention, the regenerator has a lid that closes an end of the cylinder so that refrigerant gas can flow therethrough, and at least two types of granular material that are filled in a layer in the cylinder in the axial direction of the cylinder. A cold storage material, and a partition member that is inserted into the cylinder so as to be located at the boundary between the different types of cold storage material and that allows refrigerant gas to flow therethrough. Of a material having an expansion coefficient of. Further, in the invention of claim 3, the lid of the regenerator in the cryogenic refrigerator of the invention of claim 2 is made of a material having a zero or negative expansion coefficient with respect to temperature. According to each of these inventions, even during the operation of the refrigerator, even when the outer diameter of the lid portion and the sorting member is reduced so as to have a clearance necessary to be inserted into the cylinder during manufacture of the regenerator, The outer diameter of the lid and the partitioning member is relatively increased with respect to the cylinder, and the gap between the outer peripheral surface of the lid and the partitioning member and the inner peripheral surface of the cylinder becomes sufficiently small or zero. It is possible to suppress the occurrence of the drift of the refrigerant gas inside and improve and maintain the cooling performance of the refrigerator.

According to the fourth aspect of the present invention, the expansion coefficients of the plurality of sorting members with respect to the temperature are made different depending on the cooling temperature position of the regenerator. Further, in the invention of claim 5, the lids located at both ends of the cylinder have different expansion rates with respect to the temperature. Therefore, according to these inventions, the expansion coefficient of the lid and the partitioning member appropriately corresponds to the temperature range in the regenerator, and the gap between the cylinder and the lid or the partitioning member during operation of the refrigerator. The gap can be kept substantially constant.

According to the sixth aspect of the present invention, the pressure wave generating means includes a compressor for compressing the refrigerant gas, and a switching valve for switching between the high-pressure refrigerant gas from the compressor and the low-pressure refrigerant gas returning to the compressor. Thus, a desirable pressure wave generating means can be embodied.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a state in which a refrigerant gas passes through a separating member of a regenerator during operation of a refrigerator in an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a state in which a refrigerant gas passes through a lid of a regenerator during operation of a refrigerator.

FIG. 3 is a sectional view of a regenerator.

FIG. 4 is a diagram illustrating an overall configuration of a cryogenic refrigerator according to an embodiment of the present invention.

FIG. 5 is a diagram corresponding to FIG. 1 showing a state of passage of the refrigerant gas in a state where the gap between the partitioning member of the regenerator and the cylinder is increased during operation of the refrigerator.

[Description of Signs] (R) Cryogenic refrigerator (2, 3) Regenerator (5, 6) Pulse tube (9, 11) Cooling stage (16) Compressor (17) Rotary valve (switching valve) (24) Pressure wave generating means (34) Cylinder (35H, 35L) Lid (36H to 36L) Cold storage material (37H, 37L) Sorting member

Claims (6)

[Claims] 1. A pressure wave generating means (24) for generating a pressure wave of a refrigerant gas, and the refrigerant gas is repeatedly compressed and expanded by pressure waves of the refrigerant gas by the pressure wave generating means (24) to generate cold heat. At least one cooling stage (9, 11); and a regenerator (2, 11) for accumulating cold energy when the refrigerant gas expands.
3), the regenerator (3) is inserted into a cylinder (34) and an end of the cylinder (34), and a lid (35H, 35H, 35L) and the cylinder (3) closed by the lid (35H, 35L).
4) a regenerator material (36H to 36L) filled in the interior of (4), wherein the lid (35H, 35L) is made of a material having a zero or negative expansion coefficient with respect to temperature. Low temperature refrigerator. 2. A pressure wave generating means (24) for generating a pressure wave of the refrigerant gas, and the pressure wave of the refrigerant gas by the pressure wave generating means (24) repeats compression and expansion of the refrigerant gas to generate cold heat. At least one cooling stage (9, 11); and a regenerator (2, 11) for accumulating cold energy when the refrigerant gas expands.
3), the regenerator (3) is inserted into a cylinder (34) and an end of the cylinder (34), and a lid (35H, 35H, 35L) and the cylinder (3) closed by the lid (35H, 35L).
4) At least two kinds of cold storage materials (36H to 36L) filled in layers in the axial direction of the cylinder (34).
And the different types of cold storage material (3) in the cylinder (34).
6H to 36L), and a partition member (37H, 37L) through which the refrigerant gas can flow, wherein the partition member (37H, 37L) is zero or negative with respect to temperature. A cryogenic refrigerator characterized by being made of a material having an expansion coefficient of: 3. The cryogenic refrigerator according to claim 2, wherein the lid (35H, 35L) of the regenerator (3) is made of a material having a zero or negative expansion coefficient with respect to the temperature. Cryogenic refrigerator. 4. The cryogenic refrigerator according to claim 2, wherein a plurality of partitioning members (37H, 37L) are provided, and a coefficient of expansion of the plurality of partitioning members (37H, 37L) with respect to a temperature is a regenerator (3). A cryogenic refrigerator characterized by being different depending on a cooling temperature position of the cryogenic refrigerator. 5. The cryogenic refrigerator according to claim 1, wherein the lids (3) located at both ends of the cylinder (34), respectively.
(5H, 35L) at different temperatures. 6. The cryogenic refrigerator according to any one of claims 1 to 5, wherein the pressure wave generating means (24) comprises: a compressor (16) for compressing a refrigerant gas; High-pressure refrigerant gas and compressor (1
Switching valve (17) for switching between low-pressure refrigerant gas returning to 6)
And a cryogenic refrigerator comprising: