JP2000310456A - Regenerative heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To raise a thermal efficiency of a gas compression expander by preventing a reduction in an expanding work and improving heat exchanging performance of a regenerative heat exchanger. SOLUTION: In the regenerative heat exchanger 39 of a gas compression expander disposed with a cool storage material 51 having a predetermined perforating density in a cylinder to pass operating gas to the material 51 to exchange heat, the material 51 is constituted by laminating a first cool storage member 52 having a first perforating density and a second cool storage member 53 having a lower perforating density than that of the member 52.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas compression / expansion machine such as a Stirling engine used for generating power and a Stirling refrigerator used for generating low temperature, and more particularly to an improvement in heat exchange performance of a regenerative heat exchanger. Things.

[0002]

2. Description of the Related Art In recent years, there has been an urgent need to develop techniques for preserving various samples and various materials at extremely low temperatures in advanced technology fields such as the field of biotechnology and the field of electronic devices. In particular, gas compression / expansion machines such as Stirling refrigerators are attracting attention as means for achieving the extremely low temperature, and are going to be widely used for cooling, biomedical freezers, freezers, and the like for various infrared sensors, superconducting devices, and the like.

In this gas compression / expansion machine, a regenerative heat exchanger (regenerator) is provided in a working gas flow path between the expansion chamber and the compression chamber, and stores and radiates heat of the moving working gas. , A device for improving the capacity of a refrigeration system.

Hereinafter, a displacer type Stirling refrigerator having a regenerative heat exchanger disposed therein will be described.
This will be described in detail with reference to FIG.

[0005] An expansion cylinder 2 and a compression cylinder 3 are attached to the main body housing 1 at an angle difference of 90 degrees.
The displacer 6 incorporated in the expansion cylinder 2 and the compression piston 7 incorporated in the compression cylinder 3 are connected to a common crank mechanism 5 and are reciprocally driven with their phases shifted from each other.

The displacer 6 has a cylindrical body open at both ends filled with a cold storage material 14 made of a laminated member of a metal mesh member, for example.
The working gas flowing from 8 passes through the inside of the cold storage material 14,
In the process before flowing out of the other opening 19, the cold storage material 14
And heat exchange is performed.

The displacer 6 also has a function as a regenerative heat exchanger, and its heat exchange performance largely affects the coefficient of performance of the Stirling refrigerator.

As shown in FIG. 3, the expansion cylinder 2 and the compression cylinder 3 are separated from the crank chamber 12 by oil seals 8 and 9, respectively, and the base end of the expansion cylinder 2 and the base end of the compression cylinder 3 are separated from each other. Are communicated with each other by a communication pipe 4. Oil 10 is injected into the crank chamber 12.

FIG. 4 shows the operation of the Stirling refrigerator with time T on the horizontal axis and stroke S on the vertical axis.

[0010] In the Stirling refrigerator, the displacer 6 reciprocates as shown by curves B and C in FIG. 5 and the compression piston 7 reciprocates as shown by curve D in FIG. The space 11 changes in volume in a width region between the straight line A and the curve B in FIG. 5, and the compression space 13 of the compression cylinder 3 changes in volume in a width region between the curves C and D in FIG. .

As a result, in the process shown in FIG. 4, the gas in the compression space 13 is compressed and flows into the expansion cylinder 2 through the communication pipe 4 (ideally, isothermal compression). This gas passes through the cold storage material 14 in the displacer 6 in the process of FIG. 4 and exchanges heat with the cold storage material 14 to lower the temperature (constant volume cooling). The gas that has passed through the cold storage material 14 flows into the expansion space 11 of the expansion cylinder 2 in the process shown in FIG. 4, and then expands as the displacer 6 descends (ideally, isothermal expansion). Next, in the process of FIG. 4, the gas in the expansion space 11 passes through the cold storage material 14 and exchanges heat with the cold storage material 14 as the displacer 6 rises. Again flows into the compression space 13 (fixed volume heating).

As a result, the cold head 15 provided on the head of the expansion cylinder 2 is cooled.

[0013]

By the way, in the displacer 6, the cold storage material 14 made of a metal mesh member is laminated inside the cylindrical body, but the contaminant such as moisture in the refrigerator main body is used to cool the cold storage material 14. It solidified when passing through, causing clogging of the metal mesh member. And
As a result, a pressure loss occurs when the gas passes through the cold storage material 14, and the expansion work in the expansion space 11 decreases,
There is a problem in that the heat exchange efficiency in the cold storage material 14 is reduced, and thereby the coefficient of performance of the refrigerator is significantly reduced. The same applies to other gas compression / expansion machines provided with a regenerative heat exchanger, not limited to refrigerators.

An object of the present invention is to improve the heat efficiency of a gas compression expander by preventing the reduction of expansion work and improving the heat exchange performance of a regenerative heat exchanger.

[0015]

According to the present invention, a regenerative heat of a gas compression / expansion machine in which a regenerative material having a predetermined perforation density is arranged inside a cylindrical body and a heat exchange is performed by passing a working gas through the regenerative material. In the exchanger, the regenerator material is formed by laminating a first regenerative member having a first perforation density and a second regenerative member having a perforation density lower than the first regenerative member. It is characterized by the following. And, specifically, the regenerative material is composed of a laminated mesh member, and the low-temperature side end of the laminated mesh member and / or a predetermined temperature portion during continuous operation of the gas compression expander is formed by the second regenerative member. ing.

By using this configuration, the contaminant substance present inside the apparatus is solidified by the second regenerative member having a low piercing density, and the regenerator material is clogged with the solidification of the contaminant substance and the working gas passing therethrough. It is possible to suppress that the passage is closed and the expansion work is reduced and the heat exchange performance is reduced.

Preferably, the predetermined temperature portion during the continuous operation of the gas compression / expansion machine is approximately 0 degrees and / or approximately minus 80 degrees. By using this configuration, the contaminant substance formed of water or carbon dioxide generated during the continuous operation is solidified at the predetermined temperature portion.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A case where the present invention is applied to a Stirling refrigerator will be described below in detail with reference to the drawings. FIG.
1 shows a sectional view of a two-piston gas compression / expansion machine according to the present embodiment.

The two-piston gas compression / expansion machine comprises a drive unit 40 having a crank mechanism 43 composed of cranks 42a and 42b, an expansion piston lower part 31, and an expansion piston upper part 3.
9 and a compression section 20 including a compression piston 21.

The drive section 40 includes a rotor 41 for applying a rotational driving force to the crank mechanism 43, a storage tank 47 for storing oil for lubricating the crank mechanism 43, a crank 42a,
Connecting rods 44a, 44 connected to 42b
b, cross guides 45a and 45b for converting the driving force from the connecting rods 44a and 44b into linear motion.

The crank 42a and the crank 42b are eccentrically connected to the shaft 46, and the phase of the compression piston 21 is delayed by about 90 degrees with respect to the phase of the lower part 31 of the expansion piston.

The expansion portion 30 includes an expansion piston lower portion 31 and an expansion piston upper portion 3 connected to the expansion piston lower portion 31.
9, the expansion cylinder 32 (32a, 32a) that accommodates the expansion piston upper part 39 and the expansion piston upper part 31 in a reciprocating manner.
b), an expansion space 33 provided on the head side (upper side in FIG. 1) of the expansion cylinder 32, and an expansion piston lower part 31
, A buffer chamber 35 communicating with the buffer space 34, and a lower portion of the expansion piston 3
A load 62 is attached to the head of the expansion cylinder 32 and the like.

The expansion cylinder 32 is an expansion piston upper cylinder 32 in which the expansion piston upper part 39 reciprocates.
a and an expansion piston lower cylinder 32b in which an expansion piston lower part 31 reciprocates.

The upper part 39 of the expansion piston accommodates a regenerative material 51 formed by laminating a plurality of metal mesh members, and a plurality of communication holes 39 a for communicating with the expansion space 33 are provided at the upper end surface thereof.

A communication space 39b for connecting the gas flow path G2 and the upper part of the expansion piston 39 is formed at the connection between the upper part 39 of the expansion piston and the lower part 31 of the expansion piston.

Accordingly, the working gas flows into the communication space 39b from the gas flow path G2, exchanges heat with the cold storage material 51, and flows out from the communication hole 39a to the expansion space 33. When flowing from the expansion space 33 to the gas flow path G2, it flows through the reverse flow path.

Gas seals 37a and 37b are provided on the expansion piston upper portion 39 and the expansion piston lower portion 31 to increase the close contact between them and the expansion piston upper cylinder 32a and the expansion piston lower cylinder 32b.

The expansion piston rod 36 and the partition 63
An oil seal 38 is provided between the
Is prevented from entering the expansion section 30.

The compression section 20 is formed on a compression cylinder 22 for accommodating a compression piston 21, a compression space 23 provided on the head side (upper side in FIG. 1) of the compression cylinder 22, and a back pressure side of the compression cylinder 22. It has a buffer space 24, a buffer chamber 25 communicating with the buffer space 24, and the like.

A gas seal 27 is provided on the compression piston 21 so that the compression piston 21 and the compression cylinder 22
And an oil seal 28 is provided between the compression piston rod 26 and the partition 63 to prevent the oil of the drive unit 40 from entering the compression unit 20.

Further, radiating fins 64 for radiating the heat of the working gas to the outside are arranged around the compression cylinder 22 and the expansion piston lower cylinder 32b so as to cover them.

The regenerative material 51 in the upper part 39 of the expansion piston has a mesh wire diameter of 0.1 [mm], a mesh wire pitch of 0.17 [mm], and a first mesh member 52 having a mesh porosity of about 65%. (The first cold storage member), the second mesh member 53 (the second cold storage member) having a mesh wire diameter of 0.45 [mm], a mesh element wire pitch of 1.6 [mm], and a mesh porosity of about 77%. And a laminated portion of here,
As shown in FIG. 2, the mesh wire diameter and the mesh wire pitch respectively represent the diameter of the mesh wire constituting the metal mesh member and the distance between adjacent mesh wires.

Here, as shown in FIG. 1, the second mesh member 53 is connected to the low-temperature end 51a of the cold storage material 51 and to a first temperature range of approximately 0 degrees during continuous operation of the gas compression and expansion machine. A temperature section 51b and a second temperature section 51 having a temperature range of approximately minus 80 degrees during continuous operation of the gas compression / expansion machine.
The first mesh member 52 is laminated on the other cold storage material 51.

As described above, the low-temperature side end 51 of the cold storage material 51
The reason why the second mesh member 53 having a low perforation density is laminated on a is that a contaminant substance such as moisture existing inside the gas compression expander starts the operation of the apparatus, and after a lapse of a predetermined time, the low-temperature side end of the cold storage material 51. 51a is cooled to the vicinity of the freezing point temperature of the contaminant first to prevent the contaminant from solidifying on the low-temperature side end portion 51a and blocking the gas flow path.

The second mesh member 53 having a low perforation density is laminated on the first temperature portion 51b and the second temperature portion 51c of the cold storage material 51 because components such as components are continuously operated during continuous operation of the gas compression / expansion machine. The generated contaminants include:
Most of the water and carbon dioxide, the contaminant solidifies in the first temperature part 51b and the second temperature part 51c of the regenerative material 51 that is cooled to around the freezing point temperature of the contaminant during continuous operation, and the gas flow path is formed. This is to prevent blocking. Here, during continuous operation of the gas compression / expansion machine, the first
The temperature section 51b is near the freezing point temperature of water, and the second temperature section 51c is near the freezing point temperature of carbon dioxide. In FIG. 1, the low-temperature side end 51 of the cold storage material 51 is shown.
a, the second mesh member 53 is laminated on the first temperature part 51b and the second temperature part 51c, but the present invention is not limited to this, Even if the two-mesh member 53 is simply arranged, the first
An effect can be expected as compared with a member constituted only by the mesh member 52.

FIG. 1 shows a case where the radiation fins 64 are formed so as to surround the compression cylinder 22 and the expansion piston lower cylinder 32b.
The present invention is not limited to this, and the radiation fins may be formed so as to surround only the periphery of the compression cylinder 22. Of course, in this case, it goes without saying that a similar heat radiation fin may be provided around the lower cylinder of the expansion piston.

By forming the radiation fins so as to independently surround the periphery of the compression cylinder 22 and the like, the area of the radiation fins can be increased, and the heat of the working gas is transferred to the radiation fins. Since it is possible to shorten the average distance to be performed, heat can be efficiently dissipated. Therefore, when the gas compression / expansion machine is used in a refrigerator or the like, the coefficient of performance can be increased.

The description of the above embodiments is for the purpose of illustrating the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope thereof.
Further, the configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims.

For example, the cold storage material 51 is made of stainless steel, copper,
Alternatively, it may be formed from a sintered metal such as lead.

Further, the present invention is not limited to the Stirling refrigerator having the regenerative heat exchanger built in the expansion piston upper part 39 and the displacer 6 as shown in FIGS. It is needless to say that the present invention can be applied to all kinds of gas compression / expansion machines, such as those arranged in a gas compression and expansion machine.

[0041]

As described above, according to the present invention, the contaminant present inside the apparatus is solidified by the second regenerative member having a low perforation density, and the regenerative material is clogged with the solidification of the contaminant. As a result, it is possible to prevent the working gas passage passing therethrough from being blocked and the heat exchange performance from deteriorating, and to prevent a reduction in expansion work of the gas compression and expansion machine. Therefore, the thermal efficiency of the gas compression and expansion machine can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a two-piston gas compression / expansion machine according to an embodiment of the present invention.

FIG. 2 is an enlarged explanatory view of a main part of a laminated mesh member of a cold storage material 51 of the apparatus in FIG.

FIG. 3 is a sectional view of a conventional Stirling refrigerator.

FIG. 4 is a diagram illustrating a process of a Stirling refrigeration cycle.

[Explanation of symbols]

 Reference Signs List 20 compression section 21 compression piston 22 compression cylinder 23 compression space 24, 34 buffer space 25, 35 buffer chamber 28, 38 oil seal 30 expansion section 31 lower expansion piston 32a expansion piston lower cylinder 32b expansion piston lower cylinder 33 expansion space 39 expansion piston Upper part 39a Communication hole 39b Communication space 40 Drive unit 43 Crank mechanism 51 Cold storage material 52 First mesh member (first cold storage member) 53 Second mesh member (second cold storage member) 64 Radiation fin

Claims (5)

[Claims] A regenerative heat exchanger for a gas compression / expansion machine, wherein a regenerative material having a predetermined perforation density is disposed inside a cylindrical body, and a working gas is passed through the regenerative material to exchange heat. The regenerative heat exchange is characterized in that the material is formed by laminating a first regenerative member having a first perforation density and a second regenerative member having a perforation density lower than the first regenerative member. vessel. 2. The regenerative heat exchange according to claim 1, wherein the cold storage material is formed of a laminated mesh member, and at least a low-temperature side end of the laminated mesh member is formed of the second cold storage member. vessel. 3. The cold accumulating material is formed of a laminated mesh member, and at least a predetermined temperature portion of the laminated mesh member is formed by the second cold accumulating member during continuous operation of the gas compression and expansion machine. The regenerative heat exchanger according to claim 1. 4. A continuous operation of the gas compression and expansion machine,
The regenerative heat exchanger according to claim 2, wherein a predetermined temperature portion of the laminated mesh member is formed by the second regenerative member. 5. The regenerative heat exchanger according to claim 3, wherein the predetermined temperature portion is approximately 0 degrees and / or approximately −80 degrees.