JP2699939B2 - Regenerator refrigerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a regenerator-type refrigerator such as a Stirling refrigerator or a pulse tube refrigerator that obtains a refrigerating action (extremely low temperature) by repeatedly compressing and expanding a working gas. It is suitable for cooling sensors such as superconductors and infrared sensors.

[0002]

2. Description of the Related Art Conventionally, various types of pulse tube refrigerators, which are a kind of regenerator refrigerators, have been proposed in Japanese Patent Application Laid-Open No. Hei 3-2866967 and the like, and the basic structure thereof is shown in FIG. It comprises a unit 1, a regenerator 2, a pipe 3 connecting them, a pulse tube 5, a throttle valve 6, a buffer tank 7, and a cooling unit 8.

[0003] A pulse tube refrigerator has a working gas (He, N).
₂ , H ₂ , Ar, Ne, etc.)
a), the working gas is repeatedly expanded and compressed by the compression unit 1, whereby the working gas vibrates minutely in the flow path, and the working gas displacement vibrated by the regenerator 2 and the throttle valve 6. The working gas is made to work by controlling the phase of pressure and pressure displacement, and a low temperature is generated in the cooling unit (cold head) 8.

Here, the working principle of refrigeration will be briefly described. For convenience, the working gas in the flow path is regarded as a set of small units (elements). Is added, the element of the working gas slightly advances and retreats in the flow path according to the fluctuation of the pressure. As the working gas element moves forward, it is adiabatically compressed and its temperature rises. Therefore, the working gas element transfers the heat to the flow channel tube wall to lower the temperature. In this state, when the element of the working gas recedes, the element undergoes adiabatic expansion, and the temperature of the element further decreases. The element then removes heat from the channel wall. The heat of the channel wall is 1
The previous element was left during compression. In this way, heat is transferred between the elements of the working gas like a bucket brigade. The regenerator 2 ideally realizes heat exchange between the element and the flow channel wall, and finally generates a low temperature in the cooling unit 8.

[0005] In this type of refrigerator, the heat of compression generated in the compression section 1 in the compression process flows into the cooling section 8 of the refrigerator through the pipe 3 and the regenerator 2 to cause deterioration of the refrigerating performance. Had become one. Then, as a prior art, Japanese Patent Publication No. 2-52191 proposes a Stirling refrigerator having a configuration shown in FIG. In this publication, the heat of compression of the working gas compressed by the compression unit 100 is radiated to the cooler 101, and the working gas passing through the cooler 101 is cooled by the regenerator 102, passes through the pipe 103, and expands. It flows into the regenerator 105 on the part 104 side. The working gas is further cooled by the regenerator 105 and thereafter flows into the space 107 above the expansion piston 106 of the expansion section 104. This space 1
As 07 expands as the expansion piston 106 descends, the working gas expands to a low temperature.

[0006] According to the latter publication, the heat of compression of the working gas generated in the compression unit 100 is reduced by additionally installing the regenerator 102 between the cooler 101 and the pipe 103 of the compression unit 100. Heat can be radiated at the inlet of the pipe 103.

[0007]

However, in the conventional configuration described in the above-mentioned publication, even if the heat of compression by the compression section 100 can be removed by the cooler 101 and the regenerator 102, the working gas flows more thereafter. There is a problem that the gas flows into the pipe 103 having a small road cross-sectional area and is further compressed in the pipe 103 to generate heat.

Further, since the flow path diameter of the pipe 103 is small,
Heat generation due to viscous dissipation of working gas cannot be ignored. Further, by disposing the heat storage unit 102 on the compression unit 100 side, the dead volume incompressible by the compression unit 100 increases, and the compression ratio of the refrigerator decreases, which leads to a decrease in refrigeration performance. become.

In view of the above, it is an object of the present invention to provide a regenerative refrigerator that can effectively radiate the heat of the working gas in the pipe itself connecting the compression section and the expansion section.

[0010]

In order to achieve the above object, the present invention employs a technical means in which a regenerator is provided in a pipe connecting a compression section and an expansion section. Specifically, the following technical means are adopted. That is, in the first aspect of the present invention, the compression section (1) for compressing the working gas, the expansion section (A) for expanding the working gas compressed in the compression section (1), and the expansion section (A) And a regenerator (2) for accumulating cryogenic cold generated by the expansion of the working gas in the expansion section (A), and a cooling section provided in the expansion section (A) for cooling an object to be cooled. (8), in the regenerator-type refrigerator having a refrigerating action by repeatedly compressing and expanding the working gas between the compression section (1) and the expansion section (A), A regenerator (4) is provided in a pipe (3) that connects between the (1) and the expansion section (A) and allows the working gas to flow, and the regenerator (4) is provided through the regenerator (4). It is characterized by a regenerative refrigerator that releases the heat of the working gas to the outside.

According to a second aspect of the present invention, in the regenerative refrigerator according to the first aspect, the heat accumulator is provided only in the pipe (3) immediately after the compression section (1) among the pipes (3). (4) is provided. According to a third aspect of the present invention, in the regenerator refrigerator of the first aspect, the pipe (3) is provided between the compression unit (1) and the regenerator (2) of the expansion unit (A). That combine
The heat storage (4) is provided only in the pipe (3) immediately before the regenerator (2) in the pipe (3).

According to a fourth aspect of the present invention, in the regenerator of the first aspect, the regenerator (4) is divided into a plurality of portions in the pipe (3). Features. According to a fifth aspect of the present invention, in the regenerator-type refrigerator according to any one of the first to fourth aspects, the compression unit (1) and the expansion unit (A) each include a compression unit of a pulse tube refrigerator. And an expansion portion.

According to a sixth aspect of the present invention, in the regenerator-type refrigerator according to any one of the first to fourth aspects, the compression section (1) and the expansion section (A) are each a Stirling refrigerator. And a compression section and an expansion section. Note that the reference numerals in parentheses of the above-mentioned units indicate the correspondence with specific units described in the embodiments described later.

[0014]

According to the first to sixth aspects of the present invention,
The sensible heat of the working gas generated in the compression section and the pipe during the compression process is stored by the regenerator arranged in the pipe, and the regenerator is cooled by the cooler working gas flowing in the expansion process to remove the compression heat. And improve heat dissipation in the piping. Moreover, since the regenerator is arranged in the pipe without changing the inner diameter of the pipe, the dead volume does not increase.

That is, according to the present invention, the heat generated in the compression section and the pipe section is effectively radiated in the pipe without causing a decrease in the refrigerating performance due to a reduction in the compression ratio due to an increase in the dead volume, thereby cooling the refrigerator. Can prevent heat from entering the
The performance of the refrigerator can be improved. According to the second aspect of the present invention, when the pipe (3) is short as shown in FIG. 4 and heat generation due to viscous dissipation in the pipe can be neglected, the regenerator (4) is disposed immediately after the compression section (1). By doing so, by suppressing the length of the heat storage device (4), pressure loss due to the heat storage device can be prevented, and heat generated by the compression section (1) can be effectively removed.

According to the third aspect of the present invention, as shown in FIG. 5, when the pipe (3) is long and the heat generated by viscous dissipation in the pipe cannot be ignored, the heat accumulator (2) immediately before the regenerator (2). By disposing 4), it is possible to prevent the pressure loss due to the heat storage device by suppressing the length of the heat storage device (4), and to effectively remove heat generated in the compression section (1) and the pipe (3).

According to the fourth aspect of the present invention, when the shape of the pipe (3) is bent or complicated as shown in FIG. 6, the regenerator (4) is divided into a plurality of pieces in the pipe (3). By arranging, the pressure loss can be prevented as much as possible, and the heat generated in the compression section (1) and the pipe (3) can be effectively removed. As described above, according to the present invention, the cooling unit can be cooled by effectively radiating the heat generated in the compression unit and the pipe section in the pipe without causing a decrease in the refrigerating performance due to a reduction in the compression ratio due to the increase in the dead volume. It is possible to prevent heat from entering the section and to improve the performance of the refrigerator.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. (First Embodiment) FIG. 1 shows a first embodiment, and shows a configuration of a pulse tube refrigerator as an example.
By transmitting a driving force from a driving source (not shown) to a piston or the like and operating the piston or the like, the working gas (He, He,
N ₂ , H ₂ , Ar, Ne, etc.).

Reference numeral 2 denotes a regenerator which is made up of an appropriate regenerator material (specific material may be the same as the regenerator material of the regenerator 4 described later) so that the working gas can flow therethrough. It is to store cold. Reference numeral 3 denotes a pipe connecting the compression unit 1 and the regenerator 2 to allow the working gas to flow, and 4 denotes a regenerator disposed inside the pipe 3, which absorbs the heat of compression of the working gas and stores the heat. The heat is radiated to the outside through the pipe wall of the pipe 3.

Reference numeral 5 denotes a pulse tube made of a metal tube, 6 denotes a throttle valve (a throttle means for a working gas passage), 7 denotes a buffer tank, and the cross-sectional area of the passage between the pulse tube 5 and the buffer tank 7 is a throttle valve 6 To restrict the amount to a predetermined amount. Reference numeral 8 denotes a cooling unit (cold head) for cooling an object to be cooled (such as a superconductor), and has a tubular shape disposed on the end face of the regenerator 2 on the side of the pulse tube 5. The cooling section 8 is made of a metal material having a high thermal conductivity such as copper or indium, and is cooled by directly bringing an object to be cooled into contact with its outer wall surface. In addition. In this example, the regenerator 2 to the buffer tank 7
Constitutes an expansion section A of the pulse tube refrigerator.

In the first embodiment, the heat storage 4
Is characterized by the fact that. As the pipe 3, for example, a stainless steel pipe having an outer diameter of φ6 and a thickness of 1 mm is used. And the heat storage device 4 disposed in the pipe 3
As a heat storage material, nickel, a foam metal in which an innumerable number of channels are formed with a nickel-chromium alloy or the like, or a laminated wire mesh made of stainless steel, bronze, or the like, or a sphere-filled layer of a metal or ceramic is used. It is configured.

Here, the regenerator 4 fills the entire cross section of the pipe 3 (for example, the pipe 3 in the above specific example has a circular cross section having an inner diameter of 4 mm), and also extends in the longitudinal direction of the pipe 3. , Between the compression unit 1 and the regenerator 2. In the first embodiment, since it is configured as described above, the working gas compressed by the compression unit 1 in the compression process passes through the heat storage unit 4 arranged in the pipe 3. At this time, the compression heat, which is the sensible heat of the working gas, is absorbed by the regenerator 4, and the heat generated by viscous dissipation of the working gas in the pipe 3 is also absorbed by the regenerator 4.

In the expansion process in which the compression space of the compression section 1 expands, the working gas whose temperature has dropped passes from the regenerator 2 to the regenerator 4 in the pipe 3 to cool the regenerator 4 and then to the compression section. 1 is sucked into the compression space. Therefore, finally, in one cycle of compression and expansion, the heat of compression is absorbed and radiated by the regenerator 4.

In the first embodiment, as shown in FIG.
By disposing the regenerator 4 throughout the inside, heat is prevented from flowing into the regenerator 2 and the cooling unit 8 due to heat generated in the compression unit 1 and the pipe 3. In the first embodiment, as a specific means for promoting heat radiation from the pipe 3 to the outside, for example, as shown in FIG.
And a structure in which a cooling pipe 3b through which cooling water 3c circulates is wound around the outer peripheral surface of the pipe 3, as shown in FIG. (Second Embodiment) FIG. 4 shows a second embodiment. In a pulse tube refrigerator similar to the first embodiment, a pipe 3 is used.
In particular, the heat storage device 4 is arranged only in the portion immediately after the compression section 1. This example is effective when the pipe 3 is short and the heat generation due to the viscous dissipation of the working gas in the pipe 3 is negligible, and is effective in reducing the pressure loss in the heat storage unit 4. The length of the heat storage device 4 is preferably selected to be long enough to secure a necessary heat radiation amount and to minimize the pressure loss. (Third Embodiment) FIG. 5 shows a third embodiment.
In a pulse tube refrigerator similar to that of the second embodiment, a heat storage device 4 is arranged only in a portion immediately before the regenerator 2 in the pipe 3. In the present example, when the pipe 3 is long and the heat generated by viscous dissipation in the pipe 3 cannot be ignored, etc., the heat generated by viscous dissipation can be effectively absorbed by the regenerator 4 disposed immediately before the regenerator 2. . In addition, suppressing the length of the regenerator 4 is effective in reducing pressure loss. The length of the regenerator 4 may be determined as in the second embodiment. (Fourth Embodiment) FIG. 6 shows a fourth embodiment.
In the same pulse tube refrigerator as in the third embodiment,
And the regenerator 4 is arranged. When the pipe 3 is bent as shown in FIG. 6 or has a complicated shape, it is effective in reducing the pressure loss in the pipe 3. (Fifth Embodiment) FIG. 7 shows a fifth embodiment in which the present invention is applied to a Stirling refrigerator. This example is a Stirling refrigerator generally referred to as a displacer type, and includes a compression unit 1, a regenerator 2, a pipe 3, a rotor 9 eccentrically rotating with respect to a rotation center P of a drive mechanism, and a compression piston 1.
0, the cylinder 13 of the expansion section A.

In the case of the present embodiment, the regenerator 2 is connected to the rotor 9 by a first connecting rod 11 and is called a displacer which reciprocates in a cylinder 13 and plays a role of an expansion piston. The compression piston 10 is connected to the rotor 9 and the second
The regenerator 2 is connected by a connecting rod 12 and operates with a phase difference of approximately 90 ° with respect to the displacer constituted by the regenerator 2.

In this embodiment, a cooling section 8 for cooling an object to be cooled is provided at the tip of the cylinder 13 of the expansion section A. In the fifth embodiment, since the structure is as described above, the reverse Stirling cycle is performed by rotating the rotor 9 of the drive mechanism clockwise, and the compression and expansion of the working gas are repeated in the compression unit 1 and the expansion unit A. Thus, the cooling unit 8 operates as a refrigerator to obtain a low temperature.

In the Stirling refrigerator of the fifth embodiment, as in the pulse tube refrigerators of the first to fourth embodiments,
By arranging the regenerator 4 in the pipe 3 connecting the compression part 1 and the regenerator 2 of the expansion part A, the compression heat can be satisfactorily removed. The specific material and the like of the heat storage unit 4 may be the same as those of the first to fourth embodiments.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a pulse tube refrigerator showing a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view illustrating a heat radiation structure in a pipe 3 of FIG. 1;

FIG. 3 is an enlarged cross-sectional view showing another example of the heat radiation structure in the pipe 3 of FIG. 1;

FIG. 4 is an overall configuration diagram of a pulse tube refrigerator showing a second embodiment of the present invention.

FIG. 5 is an overall configuration diagram of a pulse tube refrigerator showing a third embodiment of the present invention.

FIG. 6 is an overall configuration diagram of a pulse tube refrigerator showing a fourth embodiment of the present invention.

FIG. 7 is an overall configuration diagram of a Stirling refrigerator showing a fifth embodiment of the present invention.

FIG. 8 is an overall configuration diagram of a conventional pulse tube refrigerator.

FIG. 9 is an overall configuration diagram of a conventional Stirling refrigerator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Compression part, 2 ... Cold storage, 3 ... Piping, 4 ... Heat storage, 5 ...
Pulse tube, 6: throttle valve, 7: buffer tank, 8: cooling unit, 9: rotor, 10: compression piston, 13: expansion cylinder, A: expansion unit.

Claims (6)

(57) [Claims] 1. A compression section for compressing a working gas, an expansion section for expanding the working gas compressed by the compression section, and a cryogenic temperature generated by expansion of the working gas in the expansion section. A regenerator that accumulates cold heat, and a cooling unit that is provided in the expansion unit and cools an object to be cooled, between the compression unit and the expansion unit, repeatedly compresses and expands the working gas, In a regenerator refrigerator exhibiting a refrigerating action, a regenerator is provided in a pipe that connects between the compression section and the expansion section and allows the working gas to flow therethrough. A regenerative refrigerator that releases heat of a working gas to the outside. 2. The regenerator according to claim 1, wherein the regenerator is provided only in the pipe immediately after the compression section in the pipe. 3. The pipe connects the compression section and the regenerator of the expansion section, and the regenerator is disposed only in the pipe immediately before the regenerator among the pipes. The regenerative refrigerator according to claim 1, wherein: 4. The regenerator according to claim 1, wherein the regenerator is divided into a plurality of portions in the pipe. 5. The regenerator according to claim 1, wherein the compression section and the expansion section are configured as a compression section and an expansion section of a pulse tube refrigerator, respectively. refrigerator. 6. The compressor according to claim 1, wherein the compression section and the expansion section are configured as a compression section and an expansion section of a Stirling refrigerator, respectively.
4. A regenerator-type refrigerator according to any one of the above.