JPH08334273A - Cold-storing device, and extremely low temperature refrigerator using same device - Google Patents

Abstract

PURPOSE: To improve the performance as an overall cold-storing device, and improve the refrigerating capability by improving the material and the shape of a cold-storing material which is filled on a high temperature side of the cold-storing device, for an extremely low temperature refrigerator. CONSTITUTION: A refrigerant gas is expanded in an expansion space 20 by the reciprocating motion of a displacer 18 in a cylinder 5 to lower the temperature of the refrigerant gas for an extremely low temperature refrigerator. In such a refrigerator, for a cold-storing device 28 which is housed in the displacer 18, the high temperature side is constituted of a copper granular matrix 31a, and the low temperature side is constituted of a lead granular matrix 31b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cryogenic refrigerator,
In particular, the present invention relates to an improvement in the material and shape of a regenerator material provided in a regenerator for accumulating cold heat.

[0002]

2. Description of the Related Art Conventionally, as a cryogenic refrigerator having an expander that expands a high-pressure refrigerant gas in a cylinder to generate cold, for example, as disclosed in Japanese Patent Laid-Open No. 58-214758, A compressor that compresses helium gas as a refrigerant gas, and an expander that expands the compressed gas are connected to a closed circuit by high-pressure piping and low-pressure piping, and the switching valve provided in the expander described above The high-pressure and low-pressure pipes are alternately communicated with the cylinder of the expander, and the slack piston is reciprocated in the cylinder according to the switching operation of this switching valve, and the displacer is reciprocally driven by this piston to expand the helium gas. By doing so, G- that was designed to generate cold
M cycle (Gifford McMahon cycle) helium refrigerator is known.

The structure of the peripheral portion of the expansion space in this type of refrigerator will be described. As shown in FIG. 6, a displacer (b) is reciprocally fitted in a cylinder (a) whose one end is closed. The expansion space (c) is formed between the cylinder (a) and the displacer (b). In addition, inside the displacer (b), a regenerator (e) composed of a regenerator material (d) is housed.
The expansion space side (lower side in FIG. 6) in (e) is formed on the low temperature side, and the anti-expansion space side (upper side in FIG. 6) is formed on the high temperature side. Conventionally, as the regenerator material (d) filled in the regenerator (e), a granular matrix of Ni is provided on the high temperature side (region A in FIG. 6) and Pb is provided on the low temperature side (region B in FIG. 6). It is known that a granular matrix of No. 2 is adopted, a Cu mesh matrix is adopted on the high temperature side, and a Pb granular matrix is adopted on the low temperature side.

[0004]

However, the above-mentioned cold accumulating material has the following problems. First, in the former case where the high temperature side is filled with the Ni granular matrix, since the thermal conductivity of Ni is low,
It is not possible to store cold heat even inside the particles, and it is not possible to secure a sufficient amount of heat storage on the high temperature side. Therefore, there is a limit to improving the performance of the regenerator as a whole. Further, in the latter case where the high temperature side is filled with a Cu mesh matrix, the ineffective volume inside the regenerator tends to be large, and the volume of the heat-storable portion inside the regenerator is small. Even in this case, there was a limit to improving the performance of the regenerator as a whole.

As described above, in particular, on the high temperature side of the regenerator, a heat storage material for securing a sufficient amount of heat storage has not yet been obtained.

The present invention has been made in view of the above circumstances, and improves the performance of the regenerator as a whole by improving the material and shape of the regenerator material constituting the high temperature side of the regenerator, thereby improving the performance of the refrigerator. The purpose is to improve the refrigeration capacity of.

[0007]

[Means for Solving the Problems] To achieve the above object,
In the present invention, the regenerator material filled in the regenerator is set to have a high thermal conductivity as a material and a shape that can reduce the ineffective volume in the regenerator.

Specifically, the invention according to claim 1 is a regenerator material.
The cold storage material (3) is formed by performing heat exchange between the cold storage material (31) and the cold storage material (31) introduced from one end.
It is premised on a regenerator that cools the high temperature fluid by performing heat exchange between the high temperature fluid introduced from the other end and the regenerator material (31) while storing cold heat in 1). And, the regenerator material (31a) of the portion where the high temperature fluid is introduced,
The structure is made of a copper granular matrix.

The invention according to claim 2 is a cryogenic refrigerator using the regenerator according to the invention according to claim 1. Specifically, the cold storage material (31) is formed, and by exchanging heat between the low temperature fluid introduced from one end and the cold storage material (31), cold heat is stored in the cold storage material (31). , It is premised on a cryogenic refrigerator equipped with a regenerator (28) configured to cool the high temperature fluid by performing heat exchange between the high temperature fluid introduced from the other end and the regenerator material (31). . Further, the regenerator material (31a) of the portion into which the high temperature fluid is introduced is made of a copper granular matrix.

According to a third aspect of the present invention, in the cryogenic refrigerator according to the second aspect, the regenerator (28) includes a cylinder (5).
The displacer (18) is housed in a displacer (18) that is reciprocally fitted therein, and the displacer (18) expands a space between the cold fluid introduction side of the regenerator (28) and the cylinder (5) ( 20) is partitioned and is reciprocated to expand the fluid in the expansion space (20) to lower the temperature and generate cold heat in the expansion space (20).

According to a fourth aspect of the present invention, in the cryogenic refrigerator according to the second or third aspect, the regenerator material (31b) of the portion into which the cryogenic fluid is introduced is made of a lead granular matrix. .

[0012]

According to the present invention, the following effects can be obtained in the present invention. In the inventions of claims 1 and 2, when the low temperature fluid is introduced from one end of the regenerator, heat exchange is performed between the low temperature fluid and the regenerator material (31), and the regenerator material (31) Cold heat is stored in. On the other hand, when the high temperature fluid is introduced from the other end of the regenerator, this high temperature fluid and the regenerator material (3
Heat is exchanged with 1) to cool the hot fluid. In the regenerator that exchanges heat with the fluid as described above, the regenerator material (31a) in the portion into which the high-temperature fluid is introduced is made of a granular copper matrix. Copper that constitutes the cold storage material (31a) has both high specific heat and high thermal conductivity in a high temperature region, and is suitable as a cold storage material for the portion into which the high temperature fluid is introduced. Further, by using the cold storage material (31a) as a granular matrix, it is possible to secure a large amount of cold heat storage while reducing the porosity in the regenerator as compared with a conventionally known mesh matrix.

According to the third aspect of the invention, when the low temperature fluid introduced from one end of the regenerator (28) is generated, the expansion space (2) is generated by the reciprocating motion of the displacer (18) in the cylinder (5).
The fluid in 0) is expanded to lower its temperature, thereby producing a cryogenic fluid in the expansion space (20).

In the invention according to claim 4, since lead having a large thermal conductivity at low temperature is used as the cold storage material (31b) of the portion into which the low temperature fluid is introduced as a granular matrix capable of reducing the porosity, this low temperature is used. It is possible to secure a sufficient amount of heat storage on the side.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Further, in this example, the cryogenic refrigerator according to the present invention is G-
The case of application to a helium refrigerator having M cycles will be described. FIG. 1 shows the internal structure of the expander (1) of the refrigerator. The expander (1) is connected to the compressor by a high-pressure gas pipe and a low-pressure gas pipe (both not shown) so that the helium gas as a refrigerant gas compressed by a compressor not shown can be expanded. And forms a closed circuit with the compressor.

The structure of the expander (1) will be described below. The expander (1) includes a motor housing (4) having a high-pressure side adapter (2) connected to the high-pressure gas pipe and a low-pressure side adapter (3) connected to the low-pressure gas pipe, and the motor housing (4). A cylinder (5) integrally and airtightly connected to a lower portion via a first flange (5c). The cylinder (5) includes a first cylinder portion (5a) having a relatively large diameter joined to the first flange (5c), and the first cylinder portion (5a).
And a small diameter second cylinder portion (5b) integrally arranged on the lower side with a second flange (5d) interposed. Then, inside the motor housing (4), there is a motor chamber (6) communicating with the high-voltage side adapter (2) and a through hole (7) communicating with the motor chamber (6) and extending in the vertical direction. A surge volume (9) communicating with the low-pressure side adapter (3) via an auxiliary orifice (8) is formed.

A valve stem (10) constituting the upper closed end of the cylinder (5) is fitted over the inside of the motor housing (4) and the inside of the cylinder (5).
This valve stem (10) has a valve seat (10a) that is airtightly fitted in the through hole (7) of the motor housing (4).
A drooping part (10b) formed to have a diameter smaller than the inner diameter of the first cylinder part (5a) and hanging down in the upper part of the first cylinder part (5a).
And the upper surface of the valve seat (10a) and the through hole.
The space surrounded by the wall surface of (7) forms a valve chamber (11) communicating with the high-pressure gas pipe through the motor chamber (6).

A first gas passage (12) and a second gas passage (13) extending vertically are provided inside the valve stem (10).
Are formed. The first gas flow path (12) is formed in the upper half of the valve stem (10) and has an upper end formed in the valve seat portion (1).
It has a small diameter communication passage (12a) on the upper surface of (0a) and the lower end is open inside the cylinder (5). Also,
The upper end of the second gas flow path (13) can communicate with the first gas flow path (12) via a low pressure port (27) of the rotary valve (24) described later, and the lower end of the second gas flow path (13) has the low pressure. Side adapter
It communicates with (3) through a horizontally extending communication passage (14) formed in the motor housing (4). The two gas flow passages (12) and (13) are located at the center of the valve stem (10) in the second gas flow passage (13) with respect to the valve chamber (11) on the upper surface of the valve stem (10). Further, in the communication passages (12a) of the first gas flow passage (12), they are opened to the outer periphery of the valve stem (10).

On the other hand, at the upper end of the first cylinder portion (5a) of the cylinder (5), a cup-shaped slack piston for partitioning and forming a drive space (15) at the upper end of the first cylinder portion (5a) is formed. The (16) is reciprocally fitted such that its inner surface is in sliding contact with the hanging portion (10b) of the valve stem (10) in an airtight manner. The drive space (15) is in constant communication with the surge volume (9) in the motor housing (4) via the orifice (17) formed in the valve stem (10). The slack piston (16) has a bottom wall (16a), and the bottom wall (16a) has a central hole formed in the center thereof.
(16b) and a pressure introducing hole (not shown) formed around the central hole (16b) are formed so as to penetrate therethrough, and the inner space (19a) of the slack piston (16) and the lower intermediate space are formed by each hole.
It is in communication with (19b).

A displacer (18) is reciprocally fitted in the cylinder (5). The displacer (18) is integrally formed with a closed cylindrical first body (18a) that slides in the lower half of the first cylinder portion (5a) of the cylinder (5) and the lower end of the first body (18a). And a second cylindrical body that is slid in the second cylinder part (5b) of the cylinder (5).
(18b) and the displacer (18) allows the inner space of the cylinder (5) below the slack piston (16) to be an intermediate space (19b) and a first stage expansion space (20) in order from the upper side.
And the second stage expansion space (21). Then, a first through hole of the displacer (18) is formed by a communication hole not shown.
The space in the body (18a) is the first stage expansion space (20), and the space in the second body (18b) is the second stage expansion space (21).
Is always in communication. In addition, in FIG. 1, each expansion space (20, 2
It shows the state where the volume of 1) is minimum.

Further, at the upper end of the first body (18a) of the displacer (18), a tubular slack cup for communicating the space inside the first body (18a) with the internal space (19a) of the slack piston (16). The ring (22) is integrally projected through the adapter (18c). This Slack Coupling (22)
Is the center hole (1) of the bottom wall (16a) of the slack piston (16).
6b) through the internal space (19a) of the slack piston (16)
To the top of the piston bottom wall (16a)
A flange-shaped locking portion (22a) that can be engaged with is integrally formed. Therefore, when the slack piston (16) moves upward, when the piston (16) moves upward by a predetermined stroke, the bottom wall (16a) and the locking portion of the slack coupling (22) are locked.
By engaging with (22a), displacer (18) is
The displacer (18) is configured to follow the slack piston (16) with a delay of a predetermined stroke so that the displacer (18) is driven by the (16) to start rising. In addition, a through hole (18d) communicating with the central hole (22b) of the slack coupling (22) is formed in the center of the adapter (18c).
Is formed so as to penetrate vertically, so that the space inside the first body (18a) is the inner space of the slack piston (16).
It communicates with (19a).

The inner space of the first body (18a) and the second space
The inner space of the body (18b) is defined by a coupling (25) arranged at a connecting portion between the two and a through hole (18e) formed at an upper end of the second body (18b) and vertically penetrating each other. It is in communication.

Further, in the valve chamber (11) of the motor housing (4), the valve motor (2) disposed in the motor chamber (6) is
A rotary valve (24) as a switching valve that is rotationally driven by 3) is provided, and by the switching operation of the rotary valve (24), the valve chamber (11) communicating with the high pressure gas pipe and the low pressure gas pipe are communicated. Connect the slack piston (1
6) Internal space (19a), first and second expansion spaces (20), (2
It is configured to communicate with 1) alternately.

That is, the rotary valve (24) is non-rotatably and slidably connected to the output shaft (23a) of the valve motor (23). Further, the lower surface of the rotary valve (24) is pressed against the upper surface of the valve stem (10) with a constant pressing force by the pressure of the high-pressure helium gas introduced into the valve chamber (11).

On the other hand, on the lower surface of the rotary valve (24), a pair of high pressure ports (26, 26) are formed by cutting a predetermined length in the center direction from the outer peripheral edges facing each other in the radial direction,
The rotary valve (24) is arranged at an angular interval of approximately 90 ° with respect to the high pressure ports (26, 26), and the valve (2
4) A low pressure port (27) is formed by cutting out in the diameter direction from the center of the lower surface toward the vicinity of the outer peripheral edge. Then, the rotary valve (24) is driven by driving the valve motor (23).
When the lower side of the valve stem (10) is rotated while being pressed against the upper surface of the valve stem (10) for switching operation, the slack piston (16) and displacer (1
When 8) is reciprocated in the cylinder (5) and the inner ends of the high pressure ports (26) on the lower surface of the valve (24) match the first gas flow passages (12) opening on the upper surface of the valve stem (10), respectively. , The valve chamber (11) through the high pressure port (26) and the first gas flow path (12), the internal space (19a) of the slack piston (16), the first and second
Communicate with the stepped expansion spaces (20) and (21) so that these spaces (19
By introducing and filling high pressure helium gas into a) to (21), the slack piston (16) and the displacer (18) driven by the piston (16) are raised. On the other hand, when the outer end of the low-pressure port (27), which is in constant communication with the second gas channel (13) opening on the upper surface of the valve stem (10) at the center, matches the first gas channel (12), The spaces (19a) to (21) in the cylinder (5) are connected to the first gas flow path (12) and the low pressure port (2
7), the helium gas filled in each space (19a) to (21) is connected to the low pressure gas outlet (3) through the second gas flow path (13) and the communication passage (14), The slack piston (16) and the displacer (18) are lowered by discharging the slack piston (16) into the pipe.

In addition, heat conduction is performed on the outer periphery of the lower end of each cylinder (5a, 5b) so that the cold heat generated in each expansion space (20, 21) can be efficiently transferred to an object to be cooled (not shown). A high rate copper heat station (30) is installed.

Further, a first-stage regenerator (28) is provided in the space inside the first body (18a) of the displacer (18), and a second-stage regenerator (28) is provided in the space inside the second body (18b). 29) are housed respectively. And the displacer (18) is the cylinder (5)
In the intake stroke that rises in the inside, inside the regenerators (28,29) whose temperature has dropped to the cryogenic level in the previous exhaust stroke, from the internal space (19a) of the slack piston (16) to the first or second
Helium gas at room temperature flows into the stage expansion space (20, 21) and cools the gas to near the cryogenic level by heat exchange between the two. On the other hand, during the exhaust stroke in which the displacer (18) descends, each regenerator is in the process of discharging the helium gas whose temperature has dropped to the cryogenic level due to expansion in each expansion space (20, 21) to the outside of the cylinder (5). It flows into the inside of (28,29), and by heat exchange of both, the regenerator (28,29) is cooled again to near the cryogenic level.

As a characteristic configuration of this example,
It is in the regenerator material (31, 32) that constitutes each of the regenerators (28, 29). The cold storage material (31, 32) will be described below. First, the first-stage regenerator material (31) constituting the first-stage regenerator (28), which is a feature of this example, will be described. This first stage cold storage material
(31) is provided with different cold storage materials (31a, 31b) in the upper half and the lower half of the space in the first body (18a). Specifically, the cool storage material (31a) that constitutes the upper half (high temperature side) is made up of substantially spherical copper particles packed in a matrix, and constitutes the lower half (low temperature side). The regenerator material (31b) is formed by filling substantially spherical lead particles in a matrix. That is, when the helium gas flows through the inner space of the first body (18a) from the inner space (19a) of the slack piston (16) toward the inner space of the second body (18b), the helium gas is Copper particles (31a, 31a,
After flowing through the voids between them as gas passages, the voids between the lead particles (31b, 31b,…) flow as gas passages, and when flowing through these gas passages, each particle (31a, 31b) While exchanging heat with the inner space of the first body (18a),
From the inner space of the second body (18b) to the slack piston (16)
When the helium gas flows toward the internal space (19a) of the helium gas, the helium gas flows through the voids between the lead particles (31b, 31b, ...) As gas passages, and then the copper particles (31a , 31
The gap between a, ...) Flows as a gas passage, and heat is exchanged with each particle (31b, 31a) when flowing through this gas passage. The specific particle size of each particle is, for example, 0.4 mm, and this particle size can be set arbitrarily.

On the other hand, the second-stage regenerator material (32) constituting the second-stage regenerator (29) is made up of lead particles, which are substantially spherical in shape, filled in a matrix. And the lead particles (32,32,
A space between them is used as a gas passage, and heat exchange is performed between the helium gas flowing through the gas passage and the second stage regenerator material (32). Further, of the second-stage cold storage material (32), the cold storage material that constitutes half (high temperature side) is a Cu granular matrix, and the cold storage material that constitutes the lower half (low temperature side) is Er3 Ni. May be a granular matrix.

Next, the operation of the expander (1) configured as described above will be described. The operation of the refrigerator is basically the same as that of a normal refrigerator. That is, first, when the pressure in the cylinder (5) of the expander (1) is low and the slack piston (16) and displacer (18) are at the lower end position, the valve motor (23) is driven. Due to the rotation of the rotary valve (24), the high pressure port (26) matches the first gas flow path (12) on the upper surface of the valve stem (10), and the rotary valve (24) opens to the high pressure side. Along with this, room temperature high pressure helium gas supplied from the compressor to the valve chamber (11) through the high pressure gas pipe and the motor chamber (6) of the expander (1) is supplied to the high pressure port () of the rotary valve (24). 26) and the first gas flow path
Via the (12), the intermediate space (19
It is introduced in b). Also, the gas in the internal space (19a) of the slack piston (16) is stored in each regenerator (2) inside the displacer (18).
Each of the expansion spaces (20), (21) is sequentially filled through
When passing around the regenerator material (31, 32) inside the regenerator (28, 29), the regenerator material (31, 32) has been cooled in the previous exhaust stroke, so this regenerator material (31, 32) ) And is cooled to near the cryogenic level. That is, the gas flowing through the first-stage regenerator (28) is cooled by the regenerator material (31a) made of a copper particle matrix and then cooled by the regenerator material (31b) made of a lead particle matrix. The gas flowing through the two-stage regenerator (29) is cooled by the regenerator material (32) made of a lead particle matrix. Also, the above piston (16)
The piston (16) rises due to the pressure difference between the upper drive space (15) and the lower intermediate space (19b). Then, when the rising stroke of the piston (16) reaches a predetermined value, the bottom wall (16a) of the piston (16) and the slack coupling (22) at the upper end of the displacer (18) are engaged with each other to displace ( 18)
Is pulled up by the slack piston (16) with a delay relative to the pressure change, and the upward movement of the displacer (18) causes the expansion space (20, 21) below it to be further filled with high-pressure gas (intake stroke).

After that, when the rotary valve (24) is closed, the displacer (18) also rises by the inertial force thereafter, and accordingly, the internal space (19) of the slack piston (16) is increased.
a) Helium gas in the first and second expansion space (20,21)
Go to

After the displacer (18) reaches the rising end position, the low pressure port (27) of the rotary valve (24) is aligned with the first gas passage (12) on the upper surface of the valve stem (10). The valve (24) opens to the low pressure side, and with this opening, the helium gas in each expansion space (20, 21) below the displacer (18) expands by Simon, and the expansion of this helium gas produces cold. (Expansion process).

The helium gas in this cryogenic state is
Contrary to the above gas introduction, the regenerator material in each regenerator (28,29)
(31,32) It returns to the above-mentioned internal space (19a) through the surroundings, during which it cools each regenerator material (31,32) to an extremely low temperature level while warming itself to room temperature. In other words, the second stage regenerator (29)
The gas flowing through the regenerator material (3
While cooling 2), the gas flowing through the first-stage regenerator (28) is
After cooling the regenerator material (31b) composed of a lead particle matrix, the regenerator material (31a) composed of a copper particle matrix is cooled. Then, this room temperature helium gas is further combined with the gas in the internal space (19a) in the first gas flow path (12) and the valve (24).
Low-pressure side adapter via low-pressure port (27) and communication passage (14)
(3) is discharged from the expander (1), flows through the low-pressure gas pipe to the compressor, and is sucked into the compressor. With this gas discharge, the gas pressure in the intermediate space (19b) decreases, and the slack piston (16) descends due to the pressure difference between the driving space (15) and the bottom wall (16a) of this piston (16). ) Comes into contact with the upper surface of the displacer (18), the displacer (18) is pressed and descends, and the downward movement of the displacer (18) causes the gas in the expansion space (20, 21) to expand. ) Further discharge to the outside (exhaust stroke).

Then, the rotary valve (24) is closed,
After this, the displacer (18) descends to the lower end position,
The gas in the expansion space (20, 21) is discharged and returns to the initial state. With the above, one cycle of the operation of the expander (1) is completed, and thereafter, the same operation as described above is repeated.

Next, as described above, the first stage regenerator (28)
The reason why the high temperature side of the cold storage materials (31a, 31b) constituting the above is constituted by the granular matrix (31a) of copper (Cu) and the low temperature side is constituted by the granular matrix (31b) of lead (Pb) will be explained. . FIG. 2 shows the characteristic of specific heat with respect to the temperatures of Cu and Ni. In FIG. 3, Cu, Al,
The characteristic of the thermal conductivity with respect to the temperature of Ni and Pb is shown. In addition, type 1 of Cu indicates annealed high-purity copper, and type 2 indicates oxygen-free copper. As shown in these figures, Cu has a high specific heat at high temperature as high as that of Ni (FIG. 2), and also has a higher thermal conductivity at high temperature than other materials (at 100 K, the thermal conductivity is about 5% of that of Ni). Times). Therefore, it can be seen that this Cu has excellent properties as a cold storage material particularly on the high temperature side in terms of the specific heat and the thermal conductivity. Further, FIG. 4 shows the results of analysis of the refrigerating capacity and the differential pressure in each stroke when the refrigerator is driven, when the cold storage material is a particle matrix and when it is a mesh matrix. Expansion space (In this example, the second body (18b)
(Corresponding to the internal space of the) of the total volume (Vexp) to the ratio of the invalid volume (volume part that does not store heat: Vvoid) on the horizontal axis, and considering the invalid volume with respect to the refrigerating capacity (Qideal) when there is no invalid volume. Refrigerating capacity (Qvoid) ratio,
And the above-mentioned differential pressure (ΔP) is plotted on the vertical axis. And
30% porosity when using a cold storage material as a particle matrix
And the porosity of a mesh matrix is 70
The analysis was performed as%. The porosity was previously obtained by an experiment. As a result, as shown in FIG.
Both the refrigerating capacity and the differential pressure gradually decrease with the increase of the ineffective volume of the expansion space. Especially, in the region where the ineffective volume is small, the reducing rate of the refrigerating capacity and the differential pressure with respect to the increase of the ineffective volume is remarkable. It is getting bigger. The region I has a porosity of 30%, and a porosity of 70.
Areas II show the cases of%. in this way,
Both the refrigerating capacity and the differential pressure are secured higher when the particle matrix is used than when the cold storage material is the mesh matrix. In consideration of such a point, in this example, the regenerator material (31a, 31b) constituting the first-stage regenerator (28)
The high temperature side of these is constituted by a granular copper matrix (31a).

As described above, in this example, the cool storage material (31a) is made of Cu, which has both high specific heat and high thermal conductivity at high temperature, and has the shape of the particle matrix capable of ensuring high refrigerating capacity and high differential pressure. By adopting on the high temperature side of the one-stage regenerator (28), it is possible to improve the performance of the entire refrigerator as compared with the conventional case where Ni is used as the material and the case where the mesh matrix is used as the shape. You can

Further, by adopting Pb, which has a large thermal conductivity at low temperature, as the cold storage material constituting the low temperature side of the first stage regenerator (28) (see FIG. 3), It is possible to secure a sufficient amount of heat storage, which also improves the performance of the refrigerator as a whole.

The effect of this example will be described with reference to the energy flow diagram of the refrigerator shown in FIG. 5. Motor loss such as Joule loss and iron loss and mechanical loss with respect to “electric input” (I) to the refrigerator. (Illustration work) (I)
The work amount for the original drive of the refrigerator called II) is obtained, and the non-reversible work (IV) such as adiabatic loss, leakage loss and regenerator pressure loss is subtracted from this illustrated work (III). A reversible work ”(V) (corresponding to Qideal in FIG. 4 above) is obtained. Further, a work amount as a refrigerator called "illustrated refrigerating capacity" (VIII) is obtained by subtracting the loss (VI) due to heat dissipation and the heat loss (VII) of the regenerator from the reversible work (V). Then, for this indicated refrigeration capacity (VIII), shuttle loss, pumping loss, heat conduction loss, radiant heat loss and TH
The T-loss etc. (IX) gives us the work that actually produces the cold, called the "net refrigeration capacity" (X). In such an energy flow, according to the configuration of the present example, the loss subtracted from the reversible work (V) (in particular, the heat loss VII of the regenerator) becomes small, and as a result, the net refrigerating capacity is reduced.
It is possible to secure a large (X).

The operation of the first-stage regenerator (28) at the time of manufacture is as follows: the first body (18a), the adapter (18c)
It is performed by pouring a certain amount of lead particles (31b, 31b, ...) before mounting the and then pouring copper particles (31a, 31a, ...). A complicated work such as stacking the meshes on each other is not required, and the first-stage regenerator (28) can be easily and quickly manufactured. The same applies to the case where the second-stage regenerator (29) is manufactured.

Incidentally, the present invention is not limited to the helium refrigerator having the GM cycle as in the above embodiment, but it is needless to say that the present invention can be applied to those using a refrigerant gas other than helium gas.

The cold storage material on the low temperature side is not limited to Pb, and gadolinium particles, gadolin erbium rhodium particles, or the like may be used.

[0042]

As described above, according to the present invention,
The following effects are exhibited. According to the invention described in claim 1, in the regenerator, copper having high specific heat and high thermal conductivity in a high temperature range is used as a material of the regenerator material of a portion into which the high temperature fluid is introduced. By using a granular matrix that can reduce the porosity in the regenerator as compared with the mesh matrix, a large amount of cold heat can be stored. As a result, the performance of the regenerator can be significantly improved.

According to the invention described in claim 2, since it is a cryogenic refrigerator provided with the regenerator that exhibits the effect according to the invention described in claim 1, the refrigeration performance can be improved. it can.

According to the third aspect of the invention, the structure of the cryogenic refrigerator in which the regenerator is adopted can be specifically obtained, and the low temperature fluid to be introduced into the regenerator can be reliably generated. . In addition, as the operation during the production of the regenerator, since it is performed by pouring the copper particles into the displacer, it is not necessary to perform the complicated work such as laminating the mesh like when producing the mesh matrix,
A regenerator can be manufactured easily and quickly.

According to the fourth aspect of the present invention, lead, which has a high thermal conductivity at low temperature, is used as the granular matrix capable of reducing the porosity in the regenerator material into which the low temperature fluid is introduced. A sufficient amount of heat storage can be ensured, and the performance of the entire refrigerator can be improved in combination with the effect exerted by the cold storage material on the high temperature side described above.

[Brief description of drawings]

FIG. 1 is a sectional view of an expander in a refrigerator according to an embodiment of the present invention.

FIG. 2 is a diagram showing characteristics of specific heat with respect to temperatures of Cu and Ni.

FIG. 3 is a diagram showing characteristics of thermal conductivity with respect to temperature of various metal materials.

FIG. 4 is a diagram showing characteristics of a refrigerating capacity and a differential pressure with respect to an ineffective volume ratio of an expansion space.

FIG. 5 is an energy flow diagram of a refrigerator.

FIG. 6 is a cross-sectional view showing a structure of a peripheral portion of an expansion space of a refrigerator in a conventional example.

[Explanation of symbols]

 (5) Cylinder (18) Displacer (20) 1st stage expansion space (expansion space) (28) 1st stage regenerator (regenerator) (31) 1st stage regenerator material (regenerator material) (31a) Copper granules Matrix (31b) Lead granular matrix

Claims (4)

[Claims] 1. The cold storage material (31) is formed by a cold storage material (31) and heat is exchanged between the cold storage material (31) and the cold storage material (31) to store cold heat in the cold storage material (31). In the regenerator configured to cool the high temperature fluid by performing heat exchange between the high temperature fluid introduced from the other end and the regenerator material (31), the regenerator material of the portion where the high temperature fluid is introduced ( 31a) is a regenerator characterized by being made of a granular matrix of copper. 2. The cold storage material (31) is formed of a cold storage material (31), and heat is exchanged between the cold storage material (31) and the cold storage material (31), whereby cold heat is stored in the cold storage material (31). , A regenerator (2) configured to cool the high temperature fluid by performing heat exchange between the high temperature fluid introduced from the other end and the regenerator material (31).
In the cryogenic refrigerator including 8), the regenerator material (31a) in the portion into which the high temperature fluid is introduced is made of a granular matrix of copper. 3. A regenerator (28) is housed inside a displacer (18) fitted in a cylinder (5) so as to be able to reciprocate, and the displacer (18) is regenerator (28). ), The expansion space (20) is defined between the low temperature fluid introduction side and the cylinder (5), and the fluid in the expansion space (20) is expanded by reciprocating to lower the temperature. The cryogenic refrigerator according to claim 2, wherein cold heat is generated in the inside of 20). 4. A regenerator material (31) for a portion into which a low temperature fluid is introduced.
Cryogenic refrigerator according to claim 2 or 3, characterized in that b) consists of a granular matrix of lead.