JPH06207754A - Regenerator in freezer and its manufacturing method - Google Patents

Abstract

PURPOSE:To prevent an unbalanced state of a heat exchanging operation from being produced while a loss of heat transfer caused by a partition wall being prevented and to improve an efficiency of a regenerator. CONSTITUTION:A regenerator performs a heat accumulation as well as a heating of gaseous refrigerant through a heat exchanging operation with gaseous refrigerant supplied or discharged from expansion spaces 20 and 21. Caps 36 and 37 having helium gas flowing holes 38 and 39 are fixed to both opening ends of a case 32 which is formed into a cylinder. In addition, within the case 32 piled up are in a radial direction of the case 32 and filled a column-like cold heat accumulation material layer 34 located at a center of the case 32 and a cylindrical cold heat accumulation material layer 35 located outside the column-like cold heat accumulation layer 34. In addition, each of the cold heat accumulation layers 34 and 35 is formed such that a rate of clearance of the cylindrical cold heat accumulation layer 35 located outside the layer 34 is larger than that of the column-like cold heat accumulation material layer 34. As a result, helium gas flows substantially in a uniform manner within the case 32, resulting in that the partition wall can be eliminated and an unbalanced state in heat exchanging operation can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerator (regenerative heat exchanger) used in a refrigerator and a method for manufacturing the regenerator, and more particularly to a regenerator material.

[0002]

2. Description of the Related Art Conventionally, a compressor for compressing a refrigerant gas and a compressor for compressing the refrigerant gas have been used as a cryogenic refrigerator for expanding a high pressure refrigerant gas such as helium gas to generate a cryogenic level of refrigeration. A GM refrigerator that is combined with an expander for expanding the refrigerant gas, reciprocates the displacer in the cylinder of the expander, and adiabatically expands the refrigerant gas in the expansion space to generate cold, A Stirling refrigerator is known in which a displacer of an expander is reciprocated by pulsating gas discharged from a linear motor compressor to generate cold by expansion of a refrigerant gas in an expansion space. The expander in such a cryogenic refrigerator has a built-in regenerative heat exchanger called a regenerator, and this regenerator is usually filled in a case as a displacer through which gas can flow. A matrix comprising a large number of granular lead particles, that is, a type in which a cold storage material is provided and heat is stored and heated by exchanging heat with a gas refrigerant passing through the cold storage material is generally adopted. .

However, in the above regenerator, as shown in FIG. 4, gas refrigerant flow holes (94, 95) are formed in the central portions of caps (92, 93) attached to both ends of the case (91). While being formed, the regenerator material (9
Since the porosity of 6) is formed uniformly throughout, the flow velocity V1 of the gas refrigerant flowing through the center is fast, the flow velocity V2 of the gas refrigerant flowing outside is slow, and the heat exchange becomes excessive in the center. There was a problem that the capacity was insufficient, and conversely, there was little heat exchange on the outside and the capacity was excessive, resulting in an overall imbalance in heat exchange. Therefore, in the past, Japanese Patent Laid-Open No. 2-309158
As shown in the publication, a cylindrical partition wall is provided in the case, and the inside and the outside of the partition wall are filled with a cold storage material having different porosity so that the gas refrigerant is entirely filled in the case. It has been proposed to ensure uniform flow and to prevent heat exchange imbalance.

[0004]

However, in the above-mentioned regenerator, since the partition wall is provided, there is a problem that heat conduction loss occurs. That is, since a temperature difference of about 200 ° C. occurs at both ends of the regenerator material, there is a problem that even if the partition wall is made thin, heat conduction loss occurs and the regenerator efficiency decreases.

The present invention has been made in view of the above problems. A first object of the present invention is to prevent heat conduction loss due to a partition wall and prevent unbalance of heat exchange to improve regenerator efficiency. Especially. A second object of the present invention is to realize a method capable of manufacturing the above regenerator.

[0006]

In order to achieve the above object, the means taken by the present invention is to form a plurality of cold storage material layers having different porosities so as to be in direct contact with each other. That is, as shown in FIG. 2 and FIG. 3, in order to achieve the first object, the means taken by the invention according to claim 1 is a gas refrigerant which is first supplied to and discharged from the expansion space (20, 21). It is premised on a regenerator of a refrigerator that stores heat and heats a gas refrigerant by exchanging heat with. Then, the gas refrigerant flow holes (38, 3
Caps (36, 37) with 9) are fitted. Furthermore, in the case (32), a columnar cold storage material layer (34) located on the center of the case (32) and one or more tubular shapes located outside the columnar cold storage material layer (34) Cooling material layer (35) and case (3
It is stacked and filled in the radial direction of 2). In addition, each of the cold storage material layers (34, 35) is formed from the columnar cold storage material layer (34) to the case (3
2) The structure is formed such that the porosity increases as it goes to the tubular cold storage material layer (35) located on the outer side of the inside.

In order to achieve the second object, the means taken by the invention according to claim 2 is, as a method for manufacturing a regenerator for a cryogenic refrigerator according to claim 1, first of all, a case (32) The columnar cold storage material layer (34) located on the center and the columnar cold storage material layer (3
One or more tubular cold storage material layers (35) located outside 4) and the tubular cold storage material layers (35) located outside the columnar cold storage material layer (34) inside the case (32). The inner wall surface of the case (32) and the cylindrical regenerator material layer (35) are longer than the effective filling length of the case (32) and formed so that the porosity increases as
And a space between the cold storage material layers (34, 35). Then, with the cap (37) attached to one end of the case (32), the cold storage material layers (34, 35) are inserted from the opening end of the other end. After that, the opening end of the case (32) is closely contacted between the inner peripheral surface of the case (32) and the tubular cold storage material layer (35) and between the cold storage material layers (34, 35). The cold storage material layers (34, 35) are compressed in the longitudinal direction, a cap (36) is attached, and the cold storage material layers (34, 35) are filled in the case (32).

[0008]

With the above construction, in the invention according to claim 1,
The gas refrigerant supplied to and exhausted from the expansion spaces (20, 21) passes through the inside of the regenerator case (32), and each regenerator material layer (3) in the case (32) is discharged.
4, 35) exchanges heat with the other to store heat and heat the gas refrigerant. In this case (32), a plurality of cool storage material layers (34, 35) are laminated in the radial direction, and the columnar cool storage material layer (34) at the central portion goes to the outer cylindrical cool storage material layer (35). Since it is formed so that the porosity increases according to
(38, 39) flows into the case (32) from the columnar cold storage material layer (34) into the case (32): Since the columnar cold storage material layer (34) has a small porosity, the outer tubular cold storage material layer ( It will also be dispersed in 35). From this, the gas refrigerant, each cold storage material layer (34,
35) will flow almost uniformly. As a result, the heat exchange between the cold storage material layers (34, 35) and the gas refrigerant is performed almost uniformly, and the regenerator efficiency is improved.

According to the second aspect of the invention, the cold storage material layers (34, 35) are formed to be slightly longer than the effective filling length of the case (32), and the cold storage material layers (34, 35) are formed as cases. After inserting it into the (32), compress each cold storage material layer (34, 35) in the longitudinal direction and
Since it is filled in 2), each of the cold storage material layers (34, 35) bulges slightly outward, and each of the cold storage material layers (34, 35) are in close contact with each other,
Since the case (32) and the tubular cold storage material layer (35) are in close contact with each other, there is no gap between the cold storage material layers (34, 35) and the like, and blow-through of the gas refrigerant is prevented.

[0010]

Therefore, according to the invention of claim 1,
A plurality of cool storage material layers (34, 35) are laminated in the radial direction, and the porosity increases from the columnar cool storage material layer (34) at the center to the outer cylindrical cool storage material layer (35). In addition, the gas refrigerant is added to the outer cylindrical regenerator material layer (35).
Will also be dispersed. As a result, each cold storage material layer (3
Since the flow rate of the gas refrigerant flowing through the cooling medium can be made substantially uniform, the heat exchange between each of the cold storage material layers (34, 35) and the gas refrigerant can be carried out almost uniformly. Since it is possible to reliably prevent the generation of the insufficient portion and the excessive portion of the exchange capacity, it is possible to improve the regenerator efficiency. Furthermore, since the cold storage material layers (34, 35) are closely contacted without providing a partition wall between the cold storage material layers (34, 35), heat conduction loss can be reduced. It is possible to improve the efficiency of the regenerator.

According to the second aspect of the invention, the regenerator material layers (34, 35) are formed to be slightly longer than the effective filling length of the case (32), and the regenerator material layers (34, 35) are formed. After inserting into the case (32), compress each cold storage material layer (34, 35) in the longitudinal direction.
In order to fill the (32), each of the cold storage material layers (34, 3
The cold storage material layers (34, 35) can be brought into close contact with each other by the bulging of 5), and the case (32) and the tubular cold storage material layer (35)
And can be close to each other. As a result, it is possible to reliably prevent a gap between the cold storage material layers (34, 35) and the like, and prevent blow-through of the gas refrigerant.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a helium refrigerator having a GM cycle as a cryogenic refrigerator according to an embodiment of the present invention, (1)
Is an expander that expands helium gas as a refrigerant gas compressed by a compressor (not shown), and this expander (1)
Are connected to the compressor by high-pressure and low-pressure gas pipes (both not shown) to form a closed circuit. The expander (1) has a high pressure gas inlet (2) to which the high pressure gas pipe is connected and a low pressure gas outlet to which the low pressure gas pipe is connected.
A valve housing (4) having (3) and a large diameter portion on the upper side, which is integrally airtightly joined to the lower portion of the valve housing (4).
Cylinder with two-stage structure consisting of (5a) and lower small diameter part (5b)
(5) and the inside of the valve housing (4) is
A motor chamber (6) communicating with the high pressure gas inlet (2), a vertical through hole (7) communicating with the motor chamber (6), and an auxiliary orifice (8) at the low pressure gas outlet (3). And a surge volume (9) communicating therewith is formed.

A valve stem (10) constituting the upper closed end of the cylinder (5) is provided at the joint between the valve housing (4) and the cylinder (5). ) Is a valve seat part (10a) that is airtightly fitted in the through hole (7) of the valve housing (4) and a hanging part (10b) that hangs above the cylinder large diameter part (5a). A through hole (7) provided above the valve seat (10a)
The interior of the is formed in a valve chamber (11) communicating with the high-pressure gas pipe via the motor chamber (6). Further, the valve stem (10) has two branch flow passages (12a, 12a) in the upper half.
The first gas flow path (12) which is branched into the first chamber and communicates with the valve chamber (11) and the cylinder (5), and one end of which is connected to the first low pressure port (27) of the rotary valve (24) which will be described later. Gas flow path (12)
And a second gas flow path (13) which is connected to the low pressure gas outlet (3) through the communication passage (14) formed in the valve housing (4) at the other end. Then, the second gas flow path (13) is provided at the center of the upper surface of the valve stem (10).
The branch passages (12a, 12a) of the first gas passage (12) are opened at symmetrical positions with respect to the opening of the second gas passage (13) on the upper surface of the valve stem (10).

On the other hand, the large diameter portion (5
At the upper end of (a), a substantially cup-shaped slack piston (16) for partitioning and forming a drive space (15) in the upper part of the cylinder large diameter part (5a) is formed on the inner surface of the upper end of the valve stem (10). ) Is fitted to the hanging part (10b) in an airtight manner so as to be able to reciprocate.
The surge volume (9) in (4) is in constant communication with the orifice (17). The slack piston (16) is the bottom wall
The bottom wall (16a) has a central hole (16b) and a communication hole (16c) communicating with the inside and outside of the piston (16). Also, inside the cylinder (5), the displacer (1
8) is fitted so that it can reciprocate. The displacer (1
8) is a closed cylindrical large diameter portion (18a) that slides in the lower half of the large diameter portion (5a) of the cylinder (5) and is integrally formed at the lower end of the large diameter portion (18a). It consists of a closed cylindrical small diameter part (18b) that slides in the small diameter part (5b) of (5), and this displacer (18) allows the space inside the cylinder (5) below the slack piston (16) to be on the upper side. It is divided into an intermediate space (19), a first-stage expansion space (20) and a second-stage expansion space (21) in this order.
The space in the large diameter portion (18a) of the displacer (18) is always communicated with the first stage expansion space (20) through the lower circulation hole (18c), and also in the small diameter portion (18b). The space is always communicated with both the first-stage and second-stage expansion spaces (20, 21) through the upper circulation hole (18d) and the lower circulation hole (18e).

Further, the large diameter portion (1) of the displacer (18) is
8a), the upper cap (3
6) is provided, and the upper cap (36) has a large diameter portion (18a).
An upper flow hole (3 that communicates the internal space with the intermediate space (19)
8) is drilled and a tubular locking piece (22) is integrally projected. The locking piece (22) penetrates through the center hole (16b) of the slack piston bottom wall (16a) and extends to the inside of the piston (16) by a predetermined dimension, and the piston bottom wall (16
A flange-shaped locking portion (22a) that engages with (a) is integrally formed. Then, when the slack piston (16) moves upward, the locking portion (22a) engages with the bottom wall (16a) of the piston (16) when the piston (16) moves upward by a predetermined stroke, and the displacer (18) moves the piston (16) The displacer (18) is moved to follow the piston (16) with a delay of a predetermined stroke so that the displacer (18) is driven by the drive mechanism (16) to start rising.

Further, in the valve chamber (11) of the valve housing (4), the valve motor (2) arranged in the motor chamber (6) is
A rotary valve (24) rotationally driven by 3) is provided, and a switching operation of the rotary valve (24) causes a valve chamber (11) communicating with the high pressure gas pipe and a communication passage (communicating passage communicating with the low pressure gas pipe). 14) and the intermediate space (19) in the cylinder (5), the first
And the second stage expansion spaces (20, 21) are alternately communicated. That is, the rotary valve (24)
Is non-rotatably and slidably connected to the output shaft (23a) of the valve motor (23). Further, a spring (25) is compressed between the upper surface of the valve (24) and the motor (23), and the spring force of this spring (25) and the high-pressure helium gas introduced into the valve chamber (11). Rotary valve by pressure
The lower surface of (24) is pressed against the upper surface of the valve stem (10) with a constant pressing force.

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 central direction from the outer peripheral edges facing each other in the radial direction,
The high pressure ports (26, 26) are arranged at an angular interval of approximately 90 ° in the rotational direction of the rotary valve (24), 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. When the rotary valve (24) is rotated by the drive of the valve motor (23) while pressing its lower surface against the upper surface of the valve stem (10) to perform the switching operation, the slack is changed according to the switching operation of the rotary valve (24). Piston (16) and Displacer (18)
Reciprocate in the cylinder (5). And valves (24)
When the inner ends of the high pressure ports (26, 26) on the lower surface match the first gas flow passages (12), the valve chamber (11) is moved to the high pressure port.
These spaces are communicated with the intermediate space (19) in the cylinder (5) and the first and second expansion spaces (20, 21) through the (26, 26) and the first gas flow path (12). By introducing and filling high-pressure helium gas into (19-21), the slack piston (16) and the displacer (18) driven by the piston (16)
Raise. On the other hand, when the outer end of the low pressure port (27), which is in constant communication with the second gas flow path (13), matches the first gas flow path (12), each space (19 to 21) in the cylinder (5). ) Is the first gas flow path (12), low pressure port (27), second gas flow path (13)
And the low-pressure gas outlet (3) through the communication passage (14) to discharge the helium gas filled in each space (19 to 21) into the low-pressure gas pipe.
(16) and displacer (18) are lowered, and the expansion space (20,
Cold is generated by the expansion of the helium gas in 21).

Further, the large diameter portion (1
In the space inside 8a) there is a first stage regenerator (30) consisting of a heat storage type heat exchanger, and in the space inside the small diameter part (18b) there is a similar second stage regenerator (31). Each is fitted. As shown in FIG. 2, each of the regenerators (30, 31) has a case (32) filled with a regenerator material (33), and voids in the regenerator material (33) serve as gas passages. There is. Then, when the displacer (18) is in the intake stroke in which it rises in the cylinder (5), the regenerators (30, 30,
The regenerator material (33) of (31) is brought into contact with the helium gas at room temperature which goes from the intermediate space (19) to the first or second expansion space (20, 21), and the heat exchange between the two makes the gas extremely low temperature. Cool to near level. On the other hand, during the exhaust stroke in which the displacer (18) descends, each regeneration is performed while 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). The regenerator (3) is brought into contact with the regenerator material (33) of the regenerator (30, 31) by heat exchange between them.
0, 31) is recooled to near the cryogenic level.

As shown in FIG. 2, each of the regenerators (30, 31) has a cylindrical case (32) having a columnar cold storage material layer (34) and a tubular cold storage material layer (35). It is formed by filling the material (33). An upper cap (36) and a lower cap (37) are attached to both open ends of the case (32), and the upper cap (36) has a through hole (38) on the center thereof.
Is formed over both upper and lower surfaces, and the lower cap (37) has an inverted T-shaped through hole (39) having an inner end on the center of the inner surface and an outer end on both side surfaces. There is. Each of the circulation holes (38, 39) communicates the outside and the inside of the case (32) with each other.
The circulation hole (39) of the lower cap (37) in the first-stage regenerator (30) is, as described above, formed in the lower circulation hole (18c) of the large diameter portion (18a) of the displacer (18). The flow hole (38) of the upper cap (36) is an upper flow hole (38) in the large diameter portion (18a) of the displacer (18), and the locking piece (22) is attached to the upper cap (36). Are formed. still,
In the second-stage regenerator (31), the locking piece (22) in the first-stage regenerator (30) is not formed, and the flow hole (38) of the upper cap (36) has the displacer (18). Communicating with the upper flow hole (18d) in the small diameter portion (18b) of the lower cap (37), the flow hole (39) of the lower cap (37) is
It is a lower flow hole (18e) in the small diameter part (18b) of 8), and other configurations are the same as those of the first stage regenerator (30).

The columnar cool storage material layer (34) and the tubular cool storage material layer (3
5) is a feature of the present invention, and the case (32)
The first stage regenerator (30) is formed of a fiber mesh such as copper fiber, and the second stage regenerator is
In (31), it is formed of a fiber mesh such as lead fiber. The columnar cold storage material layer (34) is formed in a cylindrical shape having a smaller diameter than the case (32) and is provided on the center of the case (32).
The tubular cold storage material layer (35), the outer diameter is the inner diameter of the case (32),
The inner wall surface of the case (32) and the columnar cold storage material layer are formed in a cylindrical shape whose inner diameter matches the outer diameter of the columnar cold storage material layer (34).
The cylindrical cold storage material layer is provided between the outer peripheral surface of (34) and
The outer peripheral surface of (35) is in close contact with the inner peripheral surface of the case (32), and the inner peripheral surface of the tubular regenerator material (35) is in close contact with the outer peripheral surface of the columnar regenerator material layer (34). Furthermore, the columnar cold storage material layer (34) and the tubular cold storage material layer (3
5) and is formed so that the porosity of the central columnar cold storage material layer (34) is smaller than the void rate of the outer cylindrical cold storage material layer (35), specifically, for example, the columnar cold storage material The porosity of the layer (34) is 8
The porosity of the cylindrical regenerator material layer (35) is set to 0% and 85%.

Therefore, a method of manufacturing the regenerator (30, 31) will be described next. First, the columnar cold storage material layer (34) and the tubular cold storage material layer (35) are formed into a cylindrical shape and a cylindrical shape, respectively, with a fiber mesh such as copper fiber or lead fiber. At that time, the lengths X1 and X2 of the columnar cold storage material layer (34) and the tubular cold storage material layer (35) are formed to be slightly longer than the effective filling length X of the case (32), and the columnar shape of the central portion The length X1 of the cold storage material layer (34) is set to the outer cylindrical cold storage material layer (3
The same length as the length X2 of 5) or the columnar cold storage material layer (34)
The length X1 is made slightly longer (X <X2 ≦ X1). Furthermore, the outer diameter of the tubular cold storage material layer (35) is slightly smaller than the inner diameter of the case (32), and the outer diameter of the columnar cold storage material layer (34) is set to the tubular cold storage material layer (35).
Each of them is formed to have a diameter slightly smaller than the inner diameter of the cylindrical regenerator material layer, and the cylindrical regenerator material layer (35) is simply inserted into the case (32), and the columnar regenerator material layer (34) is formed into the tubular regenerator material layer (35). In the inserted state,
Between the case (32) and the tubular regenerator material layer (35), between the tubular regenerator material layer (35) and the columnar regenerator material layer (34), the columnar regenerator material layer has a diameter in which a small gap exists. (34) and the tubular cold storage material layer (35) are formed.

Then, one of the caps (36, 37) is attached to one end of the case (32), and, for example, the lower cap (3
7) is attached, and the cylindrical regenerator material layer (35) and the columnar regenerator material layer (34) are inserted from the opening end at the other end of the case (32). In this state, as described above, between the case (32) and the tubular cold storage material layer (35), the tubular cold storage material layer (35) and the columnar cold storage material layer (34)
There is a gap between and. Then, the cold storage material layers (34, 35) are compressed in the longitudinal direction and the upper caps (36) are attached to the open ends of the case (32). This Top Cap (36)
By mounting, the cold storage material layers (34, 35) swell in the radial direction, and the inner peripheral surface of the case (32) and the outer peripheral surface of the tubular cold storage material layer (35) and the tubular cold storage material layer ( Inner peripheral surface of 35) and columnar cold storage material layer (34)
Each regenerator material layer in the case (32) in close contact with the outer peripheral surface of
(34, 35) are filled, and the production of the regenerators (30, 31) is completed.

Next, the operation of the above embodiment will be described. The operation of the refrigerator is basically the same as that of a normal refrigerator. That is, first, the cylinder (5) in the expander (1)
When the internal pressure is low and the slack piston (16) and displacer (18) are in the lower end position, the rotary valve (24) is rotated by the drive of the valve motor (23), and its high pressure port ( 26, 26) is the valve stem (10)
A rotary valve (24) matching the first gas flow path (12) on the upper surface
Opens to the high pressure side. Along with this, the high-pressure helium gas at room temperature supplied from the compressor to the valve chamber (11) through the high-pressure gas pipe and the motor chamber (6) of the expander (1) becomes the high pressure of the rotary valve (24). Port (26, 26) and first gas flow path (1
It is introduced into the intermediate space (19) via 2). Further, this helium gas is sequentially filled from the intermediate space (19) through the regenerators (30, 31) of the displacer (18) into the expansion spaces (20, 21), and the regenerators (30, 31) are filled with the helium gas. While passing, it is cooled to near cryogenic levels by heat exchange with the regenerators (30, 31) that were cooled in the previous exhaust stroke. Further, the piston (16) rises due to the pressure difference between the drive space (15) above the piston (16) and the intermediate space (19) below. And this piston (16)
When the rising stroke of the piston reaches a predetermined value, the piston (16)
The bottom wall (16a) of the displacer engages with the locking piece (22) at the upper end of the displacer (18), and the displacer (18) is pulled up by the piston (16) with a delay relative to the pressure change. The upward movement of (18) causes the expansion space (20,
21) is further filled with high-pressure gas (intake stroke).

After this, when the rotary valve (24) is closed, the displacer (18) also rises due to inertial force thereafter, and accordingly, the intermediate space (1) above the displacer (18) is increased.
9) Helium gas in the first and second expansion space (20, 21)
Move to. Then, after the displacer (18) reaches the rising end position, the low pressure port (27) of the rotary valve (24) matches the first gas flow path (12), and the valve (24) opens to the low pressure side. Along with this valve opening, the helium gas in the expansion spaces (20, 21) below the displacer (18) adiabatically expands, and the expansion of the helium gas produces cold (expansion stroke).

The helium gas in this cryogenic state is
Contrary to the time of introducing the gas, the regenerator (18) passes through the regenerators (30, 31) to return to the intermediate space (19), during which each regenerator layer (30, 31) has a regenerator material layer. While cooling (34, 35) to the cryogenic level, it can be warmed to room temperature. The room temperature helium gas is further expanded together with the helium gas in the intermediate space (19) through the first gas flow path (12), the low pressure port (27) of the valve (24) and the communication path (14). (1) It is discharged to the outside and drawn into the compressor through the low-pressure gas pipe. With this gas discharge, the gas pressure in the intermediate space (19) decreases, and the slack piston (16) descends due to the pressure difference between the driving space (15) and the bottom wall (16a) of the piston (16). ) Contacts the upper surface of the displacer (18),
(18) is pressed and descends, and the downward movement of this displacer (18) causes the gas refrigerant in the expansion spaces (20, 21) to expand.
(1) Further discharged to the outside (exhaust stroke). The rotary valve (24) then closes, but after this the displacer (18)
Falls to the lower end position, and the helium gas in the expansion space (20, 21) is discharged to return 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.

In this embodiment, each of the regenerators (30, 31), which is a feature of the present invention, has a columnar cold storage material layer (34) inside a case (32).
And the cylindrical regenerator material layer (35) are laminated in the radial direction to reduce the porosity of the columnar regenerator material layer (34) at the center and increase the porosity of the outer tubular regenerator material layer (35). Therefore, the helium gas flows into the case (32) from one of the circulation holes (38, 39) toward the columnar cold storage material layer (34).
Since the porosity of 4) is small, the outer cylindrical cold storage material layer (35)
Will also be dispersed. From this, the helium gas flows in the cold storage material layers (34, 35) almost uniformly. As a result, the heat exchange between the cold storage material layers (34, 35) and the helium gas is carried out almost uniformly. Also,
The lengths X1 and X2 of the cold storage material layers (34, 35) are formed to be slightly longer than the effective filling length X of the case (32), and the cold storage material layers (34, 3) are formed.
After inserting (5) into the case (32), compress the cold storage material layers (34, 35) in the longitudinal direction and fill the case (32) with each regenerator (30, 3).
Since 1) is manufactured, the cold storage material layers (34, 35) bulge slightly outward so that the cold storage material layers (34, 35) are in contact with each other and the case (3
2) and the tubular cold storage material layer (35) are in close contact with each other without a gap.

Therefore, according to this embodiment, the columnar regenerator material layer (34) and the tubular regenerator material layer (35) are laminated in the radial direction, and the central columnar regenerator material layer (34) is formed. ) Has a small porosity and the outer cylindrical cold storage material layer (35) has a large porosity.Helium gas is also dispersed in the outer cylindrical cold storage material layer (35). It will be. As a result, since the flow rate of the helium gas flowing through the cold storage material layers (34, 35) can be made substantially uniform, the heat exchange between the cold storage material layers (34, 35) and the helium gas can be made almost uniform. Can be done evenly,
Since it is possible to reliably prevent the generation of the insufficient portion and the excessive portion of the heat exchange capacity, it is possible to improve the regenerator efficiency. Furthermore, each cold storage material layer (3) is provided without providing a partition wall between the columnar cold storage material layer (34) and the tubular cold storage material layer (35).
4, 35) are in close contact with each other, so that heat conduction loss can be reduced and regenerator efficiency can be improved. Further, according to the manufacturing method of the regenerator (30, 31), each cold storage material layer (34, 35) is formed to be slightly longer than the effective filling length X of the case (32), and each cold storage material layer (34 (34, 35) are inserted into the case (32), the respective cold storage material layers (34, 35) are compressed in the longitudinal direction so as to be filled in the case (32). 3
The cold storage material layers (34, 35) can be brought into close contact with each other by bulging (4, 35), and the case (32) and the tubular cold storage material layer
(35) and can be in close contact with each other. As a result, it is possible to surely prevent the gaps between the cold storage material layers (34, 35) and the like, so that it is possible to prevent blow-through of the helium gas.

In this embodiment, the regenerator material (33) is used.
Although the columnar cold storage material layer (34) and the tubular cold storage material layer (35) are formed in two layers, the present invention may be formed in three or more layers. At that time, the porosity is formed so as to increase toward the outer layer of the cold storage material layer. Further, the present invention is not limited to the helium refrigerator having the GM cycle as in the above embodiment, but uses a regenerator in a heat pump device such as a Stirling refrigerator or a Bilmeier heat pump device, or a refrigerant gas other than helium gas. Of course, it can also be applied to those that do.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view showing the overall configuration of a cryogenic refrigerator.

FIG. 2 is an enlarged cross-sectional view showing a regenerator.

FIG. 3 is a perspective view of a main part of the regenerator showing a state in which each cold storage material layer is inserted into a case.

FIG. 4 is an enlarged cross-sectional view showing a conventional regenerator.

[Explanation of symbols]

 1 Expander 5 Cylinder 18 Displacer 20,21 Expansion space 30,31 Regenerator 32 Case 34 Columnar regenerator material layer 35 Cylindrical regenerator material layer 36,37 Cap 38,39 Circulation hole

Claims (2)

[Claims] 1. A regenerator of a refrigerator in which heat is stored and gas refrigerant is heated by exchanging heat with the gas refrigerant supplied to and discharged from the expansion space (20, 21), and a cylindrical case ( While the caps (36, 37) having the gas refrigerant circulation holes (38, 39) are attached to both open ends of (32), the columnar shape located on the center of the case (32) is provided in the case (32). The cool storage material layer (34) and one or more tubular cool storage material layers (35) located outside the columnar cool storage material layer (34) are stacked in the radial direction of the case (32) and filled. The respective cold storage material layers (34, 35) are formed such that the porosity increases from the columnar cold storage material layer (34) to the tubular cold storage material layer (35) located outside the case (32). Refrigerator regenerator characterized by being 2. The method for manufacturing a regenerator for a refrigerator according to claim 1, wherein the columnar cold storage material layer (34) is located on the center of the case (32), and the outside of the columnar cold storage material layer (34). And one or more tubular cold storage material layers (35) located at the column-shaped cold storage material layer (34) to the case (32).
The cylindrical cold storage material layer (35) located on the outer side of the inside is formed so that the porosity increases, and the case (3
It is longer than the effective filling length of 2) and has an outer shape with a small gap between the inner peripheral surface of the case (32) and the tubular cold storage material layer (35) and between each cold storage material layer (34, 35). , With the cap (37) attached to one end of the case (32), insert each of the cold storage material layers (34, 35) from the open end of the other end, and then open the open end of the case (32). Between the inner peripheral surface of the case (32) and the cylindrical regenerator material layer (35) and each regenerator material layer (34, 35).
The cold storage material layers (34, 35) are compressed in the longitudinal direction so that the spaces are closely attached, and the caps (36) are attached, and the cold storage material layers (34, 35) are filled in the case (32). A method of manufacturing a regenerator of a refrigerator, which is characterized by the above.