JP2001263841A - Pulse tube refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse tube refrigerator capable of performing a high refrigerating capability. SOLUTION: A double-tube structure has an inner cylinder and an outer cylinder formed with low-temperature ends and high-temperature ends. An internal space is formed at an inside of the inner cylinder, and an external space is formed between the inner cylinder and the outer cylinder. The internal space communicates with the external space at the lower-temperature ends. A cool storage material is filled in one of the internal and external spaces. A heat insulation layer is disposed between the internal space and the external space. A gas supply means repeats a supply of the gas to the high-temperature end of the space filled with the storage material of the internal and external spaces and a recovery of the gas from the high-temperature end of the space.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse tube refrigerator, and more particularly, to a pulse tube refrigerator having a double structure.

[0002]

2. Description of the Related Art Referring to FIG.
A conventional double-tube pulse tube refrigerator disclosed in Japanese Patent Application Laid-Open Publication No. H10-26095 will be described.

[0003] A conventional pulse tube refrigerator having a double tube structure has a double tube comprising an inner tube 100 and an outer tube 101, and a heat absorbing section 10.
3. It is configured to include the gas compressor 104 and the gas flow path 105. The space inside the inner cylinder 100 is filled with a cold storage material 102. The space 106 between the inner tube 100 and the outer tube 101 acts as a cavity in the pulse tube.

[0004] A heat absorbing section 103 communicates the low-temperature end of the space 106 with the low-temperature end of the internal space of the inner cylinder 100. A gas compressor 104 is connected to a high-temperature end of a space in the inner cylinder 100 via a gas flow path 105. The gas compressor 104
When the supply and the recovery of the refrigerant gas are repeated periodically, heat is absorbed at the low temperature end as in the case of a normal folded pulse tube refrigerator.

[0005]

It has been found that the conventional double-tube pulse tube refrigerator shown in FIG. 3 may not be able to exhibit the desired refrigerating capacity.

An object of the present invention is to provide a double-tube pulse tube refrigerator capable of exhibiting a high refrigeration capacity.

[0007]

According to one aspect of the present invention, there is provided an inner cylinder defined by a low temperature end and a high temperature end, an outer cylinder, an inner space defined inside the inner cylinder, and the inner cylinder. And an outer space defined between the outer tube and the outer tube, a double-pipe structure communicating with the low-temperature end, a cold storage material filled in one of the inner space and the outer space, A heat insulating layer disposed between a space and an outer space; supply of a working gas to a high-temperature end of a space filled with the cold storage material in the inner space and the outer space; and a working gas from the high-temperature end And a gas supply unit that repeats the recovery of the pulse tube refrigerator.

The inner space and the outer space, which are not filled with the regenerator material, act as cavities in the pulse tube of a typical pulse tube refrigerator. The heat insulation layer suppresses heat conduction between the cavity in the pulse tube and the cold storage material. This allows
Improvement of refrigeration capacity is expected.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A pulse tube refrigerator having a double tube structure according to a first embodiment of the present invention will be described with reference to FIG.

FIG. 1A is a schematic sectional view of a pulse tube refrigerator according to a first embodiment, and FIG.
FIG. 3A is a cross-sectional view taken along a dashed-dotted line B1-B1. An inner cylinder 1 and an outer cylinder 2 made of stainless steel are arranged coaxially. An inner space 5 is defined inside the inner cylinder 1, and a cylindrical outer space 6 is defined between the inner cylinder 1 and the outer cylinder 2. The low temperature end 1a of the inner cylinder 1 is open, and the high temperature end 1b is closed. The low temperature end 2a of the outer cylinder 2 is closed, and the high temperature end 2b is open. The low temperature end 1a of the inner cylinder 1 is
The inner space 5 and the outer space 6 communicate with each other at a low temperature end.

The heat insulating layer 3 covers the outer peripheral surface of the inner cylinder 1. The heat insulating layer 3 is formed of a material having a lower thermal conductivity than that of the inner cylinder 1, for example, a phenol resin. The thickness of the heat insulating layer 3 is, for example, 1 to 5 mm.

The inner space 5 is partitioned by a partition wall 10 near the hot end 1b, a buffer tank 5b is defined on the hot end 1b side, and a pulse tube cavity 5a is defined on the cold end 1a side. . Orifice 11 on partition 10
Is provided, and the pulse tube cavity 5a and the buffer tank 5b communicate with each other through the orifice 11. The orifice 11 acts as a flow resistance to the flow of the working gas (helium gas) transported between the two spaces on both sides thereof.

A cold storage material 4 is filled in a cylindrical outer space 6. The cold storage material 4 is, for example, a stainless steel wire mesh. The portion that connects the inner space 5 and the outer space 6 is also filled with the cold storage material 4.

A flange 9 closes the high temperature end 2b of the outer cylinder 2. A through hole 15 is formed in the flange 9 to allow the outer space 6 to communicate with the outside. The gas supply device 20 is connected to the through hole 15.

The gas supply device 20 includes a gas compressor 21, a high pressure side on-off valve 22, and a low pressure side on-off valve 23. The high pressure side on-off valve 22 is inserted into a gas flow path connecting the discharge hole of the gas compressor 21 and the through hole 15, and the low pressure side on / off valve 23 connects the intake port of the gas compressor 21 and the through hole 15. Into the gas flow path.

When the high-pressure side on-off valve 22 is opened and the low-pressure side on-off valve 23 is closed, the gas compressor 21 enters the outside space 6.
A compressed working gas is supplied. This working gas passes through the outer space 6 and flows into the pulse tube cavity 5a. The working gas exchanges heat with the cold storage material 4 when passing through the outer space 6. When the working gas flows into the inner space 5, the working gas already existing in the pulse tube cavity 5a is pushed by the newly flowing working gas and moves toward the high temperature end 1b.

As a result, the pressure in the pulse tube cavity 5a becomes higher than the pressure in the buffer tank 5b, and the working gas flows into the buffer tank 5b through the orifice 11. At this time, heat is generated at the high temperature end of the pulse tube cavity 5a. This heat is radiated to the outside via the flange 9 and the like.

Next, the high pressure side on / off valve 22 is closed and the low pressure side on / off valve 23 is opened. The working gas in the pulse tube cavity 5 a flows into the outer space 6, cools the cold storage material 4, rises in temperature, and returns to the intake port of the gas compressor 21. At this time, the working gas in the buffer tank 5b instantaneously flows into the pulse tube cavity 5a through the orifice 11.

Although the principle of the occurrence of cold due to the flow of the working gas is not clear, the pulse tube cavity 5
It is considered that when the pressure and volume of the working gas in a fluctuate with a phase difference, cold occurs at the low temperature end 1a.

According to experiments by the present inventors, it has been found that the temperature distribution of the inner cylinder 1 in the axial direction is not necessarily equal to the temperature distribution of the cold storage material 4. In the pulse tube refrigerator according to the first embodiment, the heat insulating layer 3 includes the inner cylinder 1 and the cold storage material 4.
Hinders heat conduction between them. For this reason, it is considered that a temperature distribution close to an ideal state occurs in the inner cylinder 1 and the cold storage material 4, and a decrease in refrigeration capacity is prevented.

Next, a pulse tube refrigerator according to a second embodiment will be described with reference to FIG. The first shown in FIG.
In the pulse tube refrigerator according to the embodiment, the inner space of the double tube structure acts as a pulse tube cavity, and the outer space is filled with a cold storage material. In the second embodiment, conversely, the inner space is filled with the cold storage material, and the outer space acts as a pulse tube cavity.

FIG. 2A is a schematic sectional view of a pulse tube refrigerator according to a second embodiment, and FIG.
(A) is a cross-sectional view taken along dashed-dotted line B2-B2. The configurations of the inner cylinder 1, the outer cylinder 2, the heat insulating layer 3, and the flange 9 are the same as those in the first embodiment.

An inner space 5 defined inside the inner cylinder 1
Is filled with a cold storage material 4A. The cold storage material 4 </ b> A is also filled in a portion on the low-temperature end side that connects the inner space 5 and the outer space 6.

The high temperature end 1b of the inner cylinder 1 is
Is connected. The gas supply device 20 periodically repeats the supply of the working gas to the inner space 5 and the collection of the working gas from the inner space 5. The outer space 6 is connected to a buffer tank 31 via a through hole 15 provided in the flange 9 and an orifice 30.

Also in the case of the second embodiment, the heat insulating layer 3 prevents heat conduction between the outer space 6 acting as a pulse tube cavity and the cold storage material 4A. For this reason, a decrease in the refrigerating capacity can be prevented.

In the above two embodiments, a phenol resin is used as the heat insulating layer. However, other heat insulating materials such as urethane foam and fiber reinforced resin (FRP) may be used. Also,
As the heat insulating layer, a vacuum layer that is sealed off may be used.

The present invention has been described in connection with the preferred embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0028]

As described above, according to the present invention,
The heat insulation layer arranged between the inner space and the outer space of the double pipe structure suppresses heat conduction between the two. For this reason, an ideal temperature distribution is likely to be generated in the inner space and the outer space, and a decrease in refrigeration capacity can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a pulse tube refrigerator according to a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of a pulse tube refrigerator according to a second embodiment of the present invention.

FIG. 3 is a schematic sectional view of a conventional double-tube pulse tube refrigerator.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 inner cylinder 2 outer cylinder 3 heat insulating layer 4, 4A cold storage material 5 inner space 5 a pulse tube cavity 5 b buffer tank 6 outer space 9 flange 10 partition 11 orifice 15 through hole 20 gas supply device 21 gas compressor 22 high-pressure side on-off valve 23 Low pressure on-off valve 30 Orifice 31 Buffer tank

Claims (2)

[Claims] 1. An inner space defined between a low-temperature end and a high-temperature end and an outer cylinder, and an inner space defined inside the inner cylinder and an outer space defined between the inner cylinder and the outer cylinder. And a double-pipe structure communicating with each other at a low-temperature end, a cold storage material filled in one of the inner space and the outer space, and heat insulation disposed between the inner space and the outer space. A pulse having gas supply means for repeating supply of a working gas to a high-temperature end of the space filled with the cold storage material and recovery of the working gas from the high-temperature end of the inner space and the outer space. Tube refrigerator. 2. The pulse tube refrigerator according to claim 1, wherein the heat insulating layer is a layer filled with a heat insulating material or a vacuum layer.