JP2002206816A - Cold heat storage unit and cryogenic freezer machine using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a manufacturing work for a heat storage plate and a laminating work for it in a cold heat storage unit in which several cold heat storage plates made of metallic fiber are laminated in a case. SOLUTION: Some metallic fibers 4 are laminated in a random manner, compressed and sintered to each other to manufacture a cold heat storage plate 3. This cold heat storage plate 3 is manufactured more easily than that of the prior art product comprised of metallic fibers and at the same time a thickness of one cold heat storage plate can be substantially increased. As a result, a handling of the cold heat storage plate 3 can be facilitated and the number of laminated plates becomes low, so that the laminating work becomes simple and the cold heat storage unit of high quality having a less degree of bending of the cold heat storage plate 3 can be attained at a low cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a regenerator used for a cryogenic refrigerator such as a pulse tube refrigerator.

[0002]

2. Description of the Related Art FIG. 4 is a longitudinal sectional view showing a conventional structure of this type of regenerator, and FIG. 5 is a perspective view of a regenerator used in the regenerator.
FIG. 5A is a partially enlarged view. 4 and 5,
The regenerator 1 is configured by stacking a plurality of regenerator plates 3 in a cylindrical case 2 having both ends opened. The cold storage plate 3 is formed by circularly punching a metal mesh woven with metal fibers 4, and has a wire diameter of about 15 to 50 μm and a mesh size of about 200 to 500 mesh. Hundreds to thousands of the cold storage plates 3 are stacked so as to be orthogonal to the axial direction of the case 2. The laminated body of the cold storage plates 3 has a small thermal resistance in the radial direction, but a large and uniform number of air passages in the axial direction due to point contact between the metal fibers, so that the fluid resistance is uniform. Constitutes a regenerator 1 having a high regenerative efficiency.

[0003]

In such a regenerator 1, since the regenerator plate 3 has a small thickness of about several tens of microns, the regenerator plate 3 is prevented from being bent and the insertion pressure is made uniform. The laminating operation, which is performed manually and carefully while visually confirming, takes a great deal of time, for example, it takes more than half a day for each layer. Further, as the strand diameter of the metal fiber decreases, the cost of weaving the metal fiber increases rapidly, while the number of the cold storage plates 3 increases. It was difficult to obtain the characteristics.

An object of the present invention is to facilitate the production and lamination work of a regenerator plate to reduce the cost of a regenerator and stabilize its characteristics.

[0005]

In order to solve the above-mentioned problems, the present invention provides a regenerator in which a plurality of regenerator plates are stacked in a cylindrical case by compressing and joining metal fibers randomly stacked. A sheet is formed, and the cold storage plate is cut out from the sheet (claim 1). This claim 1
According to the method, the thickness per one regenerator can be made much larger than before, so that lamination is facilitated, and bending and variation in lamination pressure are reduced. The metal fibers are preferably joined by sintering (claim 2) or joined by diffusion bonding (claim 3).

On the other hand, the thermal resistance of the regenerator is required to be large in the axial direction of the cold storage plate laminate and small in the radial direction.
The cold storage plate flattened by the pressure bonding has an increased contact area of the lamination surface, and the axial thermal resistance in the lamination state decreases. Therefore, when it is desired to increase the thermal resistance appropriately, it is preferable to interpose the thermal storage plate between the cold storage plates on which the thermal resistance plate for increasing the thermal resistance is laminated. A mesh plate made of a metal fiber fabric can be used as the heat resistance plate (claim 5).

[0007]

FIG. 1 is a longitudinal sectional view of a regenerator according to an embodiment of the present invention, FIG. 2 is a perspective view of a regenerator plate used in the regenerator, and FIG. 2A is a partially enlarged view. is there. Note that the same reference numerals are used for the portions corresponding to the conventional example. In FIG. 1, a regenerator 1 is configured by stacking a plurality of regenerator plates 3 in a cylindrical case 2 having both ends opened as in the conventional case. The size of the case 2 is, for example, 20 mm inside diameter.
It is about 80mm and height is about 100mm. Here, the cold storage plate 3 is configured by randomly cutting metal fibers and then cutting out a sheet formed by compression bonding.
A specific example of the manufacturing method will be described below.

That is, for example, a metal fiber made of stainless steel, copper, copper alloy or the like having a wire diameter of 30 μm is bundled, cut into an appropriate length, for example, about 40 mm to 50 mm, and then uniformly unraveled, and the direction of the fiber is adjusted. Are randomly intricately formed into a cotton-like shape, and then stacked into a certain thickness, for example, 20 mm to 100 mm, to form a plate shape. Then, it is heated while compressing it with a press, and the metal fibers are joined to each other by sintering or diffusion bonding, and the thickness having a required aperture ratio and density is, for example, 0.6 mm.
A sheet having a size of about 3 mm and a size of about several tens cm to 100 cm square is formed. As shown in FIG. 2, a disc having a diameter corresponding to the inner diameter of the case 2 is punched from the sheet to form a cold storage plate 3. The flocculation of the metal fibers may be performed by blowing the cut metal fibers by, for example, wind power.

The cold storage plate 3 thus manufactured can be formed, for example, 10 to 50 times as thick as a conventional product made of a metal fiber fabric, and the number of laminations is 1/10 to 10 times that of a conventional product having the same strand diameter. It becomes 1/50. Accordingly, the lamination time can be shortened at this ratio, and the rigidity per sheet is increased, so that the handling is facilitated and lamination errors such as bending are reduced.

[0010] The cold storage plate 3 formed by compression bonding of the metal fibers has a flat laminated surface, so that the thermal resistance of the laminated contact surface is reduced. As a result, the thermal resistance of the laminated body in the axial direction is reduced. Therefore, when it is desired to increase the thermal resistance appropriately, a thermal resistance plate for increasing the thermal resistance is inserted between the stacked cold storage plates 3. FIG.
1 is a longitudinal sectional view of a regenerator 1 showing the embodiment. That is, in FIG. 3, the cold storage plates 3 and the heat resistance plates 5 are alternately stacked in the case 2. The thermal resistance plate 5 includes
It is preferable to use a mesh plate, which is a metal fiber fabric similar to that of the related art, so that the contact area of the interposed surface with the cold storage plate 3 can be reduced and the thermal resistance can be increased. The heat resistance plate 5 may be made of a non-metallic material.
It is also possible to use a sheet made of a material having higher thermal resistance and having many holes. In the illustrated embodiment,
Although the example in which the cold storage plates 3 and the heat resistance plates 5 are alternately laminated is shown, the insertion of the heat resistance plates 5 does not necessarily have to be performed alternately with the cold storage plates 3, and the heat resistance is appropriately adjusted by increasing or decreasing the number of the inserted heat storage plates. Can be adjusted.

FIG. 6 is a system configuration diagram showing a pulse tube refrigerator using the regenerator 1. As shown in FIG. In FIG.
6 is a compressor having a piston 7, 8 is a high-temperature side heat exchanger having one end connected to one end of the compressor 6 and the other end connected to one end of the regenerator 1, and 9 is a low-temperature end 10 connected to the other end of the regenerator 1. The high-temperature end portion 11 is a pulse tube that communicates with the buffer tank 12 via the inertance tube 13. In this pulse tube refrigerator, for example, helium gas is used as a refrigerant, and the refrigerant gas compressed by the piston 7 of the compressor 6 is cooled while passing through the high-temperature side heat exchanger 8 and the regenerator 1 to form the pulse tube 9. Flows into. At this time, due to the phase control action of the refrigerant gas flowing through the inertance tube 13 and flowing out to the buffer tank 12, the refrigerant gas flowing into the pulse tube 9 performs expansion work and cools the low-temperature end portion 10. On the other hand, heat corresponding to the expansion work is radiated from the high-temperature end 11 of the pulse tube 9. When the piston 7 operates in the suction direction, the low-temperature refrigerant gas is supplied to the low-temperature end 1.
0 and the regenerator 1 are cooled and returned to the compressor 6, and by repeating this reciprocating operation, an extremely low temperature of 100 ° K or less is obtained at the low temperature end portion 10.

[0012]

As described above, according to the present invention, a cold storage plate is cut out from a sheet formed by compressively joining metal fibers that are randomly stacked, thereby forming the same wire as the conventional cold storage plate made of a wire mesh. Using metal fibers of the same diameter, the thickness per cold storage plate is increased to about 10 to 50 times, while ensuring the same heat exchange area and ventilation path opening as before, and the manufacturing cost per unit thickness is reduced. It is possible to greatly reduce the number of laminating steps and improve the laminating quality while greatly reducing the number of laminating operations, and to obtain a low-cost, high-quality regenerator.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a regenerator showing an embodiment of the present invention.

FIG. 2 is a perspective view of a cold storage plate used in the cold storage device of FIG.

FIG. 3 is a longitudinal sectional view of a regenerator showing a different embodiment of the present invention.

FIG. 4 is a system configuration diagram showing a pulse tube refrigerator using the regenerator of FIG. 1;

FIG. 5 is a longitudinal sectional view of a regenerator showing a conventional example.

6 is a perspective view of a cold storage plate used in the cold storage device of FIG.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 regenerator 2 case 3 regenerator plate 4 metal fiber 5 heat resistance plate 9 pulse tube

Claims (6)

[Claims] In a regenerator in which a plurality of cold storage plates are stacked in a cylindrical case, a sheet is formed by compressively joining metal fibers that are randomly stacked, and the cold storage plate is cut out from the sheet. Characteristic regenerator. 2. The regenerator according to claim 1, wherein said metal fibers are joined to each other by sintering. 3. The regenerator according to claim 1, wherein said metal fibers are bonded to each other by diffusion bonding. 4. The regenerator according to claim 1, wherein a heat resistance plate for increasing the thermal resistance in the axial direction of the stacked cold storage plates is interposed between the cold storage plates. 5. The regenerator according to claim 4, wherein said heat resistance plate is a mesh plate made of a metal fiber fabric. 6. A regenerator for storing cold heat by exchanging heat between a low-temperature fluid flowing from one end and a cold storage plate and cooling the high-temperature fluid by exchanging heat between the high-temperature fluid flowing from the other end and the cold storage plate. A cryogenic refrigerator comprising the regenerator according to claim 1 as the regenerator.