JP2001153479A - Refrigerating plant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the decline of the refrigerating efficiency of a refrigerating plant by reducing the pressure loss of a working medium when the medium is passed through a cold storage material due to an impurity, such as the moisture, etc. SOLUTION: A refrigerating plant is provided with an expansion section 30 which houses a displacer 31 containing a cold storage material 33 in such a way that the displacer 31 can make reciprocating motions in an expansion cylinder 32 and a driving section 20 which houses a driving mechanism 22 for moving the displacer 31 forward and backward and generates cold heat by expanding the working medium in an expanded space 34 formed in the cylinder 32 by moving the displacer 31 forward and backward in the cylinder 32. The refrigerating plant is also provided with a heating means 41 provided on the cooled section-side outer peripheral surface of the cylinder 32 and a control means 42 which controls the heating means 41. The control means 42 controls the heating means 41 to make heating operation for a fixed period of time after the refrigerating plant is actuated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration system comprising a gas compression / expansion machine such as a Stirling refrigerator used for generating a low temperature.

[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, refrigerating devices such as Stirling refrigerating machines have attracted attention as means for achieving the extremely low temperatures, and are now being widely used for cooling various types of infrared sensors, superconducting devices and the like, and for freezers and freezers for biomedical applications.

Here, the structure of a conventional displacer type Stirling refrigerator will be described with reference to FIG.

[0005] The refrigeration apparatus shown in FIG.
2, an expansion section 130 having a displacer 131, a compression section 150 having a compression piston 151, and the like.

The expansion section 130 includes an expansion cylinder 132 for accommodating a displacer 131 and an expansion space 13 provided on the head side (upper side in FIG. 5) of the expansion cylinder 132.
4. Insertion hole 1 for transmitting driving force to displacer 131
A cold head 112 serving as a part to be cooled is attached to the head of the expansion cylinder 132, having a displacer rod 135 inserted through 59 a and a cold storage material 133 provided in the displacer 131. Displacer 1
31, a cold storage material 133 made of, for example, a metal mesh member is laminated inside a cylindrical body having both ends opened, and a working gas flowing from one opening of the cylindrical body passes through the inside of the cold storage material 133, The heat exchange with the cold storage material 133 is performed in the process until it flows out of the opening of the heat storage material 133.

The compression section 150 includes a compression piston 15
1, a compression cylinder 152 for storing
The compression piston 153 is inserted through the compression space 153 and the insertion hole 159b provided on the head side (the left side in FIG.
And a compression piston rod 158 for transmitting a driving force to the motor.

[0007] On the upper side surface of the compression cylinder 152, a gas flow path G communicating with the insertion hole 159a is formed.

In such a configuration, when the motor 121 is driven and the crank mechanism 122 rotates, the rotational power is transmitted to the compression piston 151 and the displacer 131, and the phase of the compression piston 151 is shifted with respect to the displacer 131. The reciprocating motion is delayed by about 90 degrees.

[0009] When the compression piston 151 moves from the bottom dead center to the top dead center, the working gas in the compression space 153 is compressed. During this time, the displacer 131 moves upward and reaches the top dead center, and then moves downward.

The working gas compressed along with the upward movement of the compression piston 151 flows through the gas flow path G and is sent to the expansion section 130 side. When the displacer 131 moves down, the working gas passes through the cold storage material 133 and cools. The heat is exchanged with the material 133 and sent to the expansion space 134.

As the displacer 131 reaches the bottom dead center, the compression piston 151 moves from the top dead center to the bottom dead center, and the working gas expands and cools down. Since the expansion process at this time is an isothermal expansion process, external heat is absorbed as much as the temperature is reduced by the expansion. That is, heat can be taken from the cold head 112.

As the compression piston 151 approaches the bottom dead center, the displacer 131 starts moving upward, and the working gas passes through the displacer 131, absorbs heat from the cold storage material 133 and returns to the compression space 153.

By such a cycle, the compression space 15
The working gas compressed in 3 is supplied to the gas flow path G and the insertion hole 159a.
, Flows into the displacer 131, passes through the mesh-like cold storage material 133 provided in the displacer 131, flows into the expansion space 134, and expands.

The working gas expanded in the expansion space 134 follows the same path, and the displacer 131 and the insertion hole 159
a, flows into the compression space 153 via the gas flow path G.

By repeating the above cycle, the cold head 112 provided at the head of the expansion cylinder 132 is provided.
Is cooled.

[0016]

In the refrigerating apparatus having the above structure, moisture and impurity gas (for example, carbon dioxide, etc.) mixed during production and assembly, or generated from working gas and components during continuous operation. Contamination (impurities) cannot be completely removed. For this reason, the contaminants in the refrigeration apparatus body accumulate and solidify when passing through the cold storage material 133 made of a metal mesh member or the like, causing clogging of the metal mesh member or the like. Then, as a result, a pressure loss occurs when the working gas passes through the cold storage material 133, the expansion work in the expansion space 134 is reduced, and the heat exchange efficiency in the cold storage material 133 is reduced. There is a problem that the coefficient of performance of the system is greatly reduced.

Therefore, the present invention reduces the pressure loss of the working gas when passing through the cold storage material due to the impurities such as moisture.
It is an object of the present invention to provide a refrigeration apparatus that suppresses a decrease in refrigeration efficiency.

[0018]

According to the present invention, there is provided an expansion section for accommodating a displacer having a cold storage material therein in a reciprocating manner in an expansion cylinder, and a driving section for accommodating a driving mechanism for reciprocating the displacer. A refrigerating device that reciprocates the displacer in an expansion cylinder to generate cold heat by an expansion stroke of a working gas in an expansion space formed in the expansion cylinder; Heating means provided on the side surface, comprising a control means for controlling the heating means, by the control means,
The heating by the heating means is performed for a fixed time after the start of the refrigerating apparatus.

By using this configuration, the temperature of the cold storage material on the cooled part side is prevented from lowering for a certain period of time after the start of the refrigerating apparatus, and impurities (contaminants) such as moisture vapor mixed in the working gas are removed. It solidifies in the cold storage material part, and after heating, it will solidify in the cold storage material part on the part to be cooled,
It is possible to disperse the impurity solidification portions of the cold storage material and reduce the pressure loss of the working gas when passing through the cold storage material.

More specifically, a compression piston reciprocatingly reciprocatingly shifted in phase by approximately 90 degrees from the display is provided in the compression cylinder, and a compression space formed by the compression cylinder and the compression piston is provided. A refrigerating apparatus having a compression unit for compressing a working gas in the inside, wherein the compressed working gas from the compression unit flows into the expansion space, expands the working gas, and generates cold heat. With this configuration, the above-described effects can be obtained in a gas compression / expansion machine such as a Stirling refrigerator.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of the Stirling refrigerator according to the present embodiment.

The Stirling refrigerator has a crank 22a,
A drive unit 20 including a crank mechanism 22 composed of 22b;
It has an expansion section 30 provided with a displacer 31, a compression section 50 provided with a compression piston 51, and the like. The expansion section 30 and the compression section 50 are provided side by side and provided above the drive section 20.

The drive section 20 includes a motor 21 for applying a rotational driving force to the crank mechanism 22, an oil tank 23 for storing oil for lubricating the crank mechanism 22, and a crank 22.
a, connecting rod 24a connected to 22b,
24b, and cross guides 25a and 25b connected to the connecting rods 24a and 24b.

The cranks 22a and 22b are connected eccentrically to the shaft 22c, and the mounting angles of the cranks 22a and 22b are set so that the phase of the compression piston 51 is delayed by about 90 degrees with respect to the phase of the displacer 31. Is set.

The expansion section 30 includes an expansion cylinder 32 for accommodating the displacer 31, an expansion space 34 provided on the head side (upper side in FIG. 1) of the expansion cylinder 32, and a displacer rod 35 for transmitting a driving force to the displacer 31. , A cold storage material 33 provided in the displacer 31
The cold head 12 serving as a portion to be cooled is attached to the head of the expansion cylinder 32.

FIG. 2 is a detailed view showing the configuration of the expansion section 30.
A heater 41 as a heating means is wound around the outer peripheral side on the head side (upper side in FIG. 1) of the expansion cylinder 32.
Off control is being performed.

Conventionally, after the start of the refrigerating apparatus, the temperature of the regenerative material 33 in the displacer 31 decreases gradually from the cold head 12 side to have a predetermined temperature gradient. For this reason, in the conventional apparatus, the cold storage material 33 is
The second-side regenerator material portion 33a is cooled to the vicinity of the freezing point temperature of the contaminants such as moisture mixed in the working gas, but the heater 41 is energized for a certain period of time after the start of the refrigerating apparatus, thereby displacing the displacer 31. Of the working gas in the expansion space 34 on the head side of the cold storage material 3
3, the temperature of the cold head 12 is suppressed, and the other cold storage material portion 33b of the cold storage material 34 (the lower side in FIG. 2).
However, it is cooled to around the freezing point temperature of the contamination. As a result, a certain period of time after the start of the refrigerating device,
Contaminants (impurities) such as water vapor mixed in working gas
Is solidified in the cold storage material portion 33b, and after the heating by the heater 41, is solidified in the cold storage material portion 33a on the side to be cooled, dispersing the impurity solidification locations in the cold storage material 33 and passing through the cold storage material 33. The pressure loss of the working gas at the time can be reduced.

In the control circuit 42, the cold storage material portion 33a has a temperature higher than the freezing point of the contaminant for a certain period of time after the start of activation, and a portion lower than the freezing temperature of the contaminant is generated in the other cold storage material portion 33b. The energizing time and energizing voltage of the heater 41 are controlled.

In a gas compression / expansion machine such as a Stirling refrigerating machine, most of the contaminants generated from components and the like during continuous operation are water and carbon dioxide. Is such that the cold storage material portion 33a becomes 0 ° C. or higher, which is higher than the freezing point of water (about 0 ° C.) and the freezing point of carbon dioxide (about −80 ° C.), and a portion of −80 ° C. or less occurs in the other cold storage material portion 33b. The heating of the heater 41 is controlled.

The compression section 50 covers a compression cylinder 52 for accommodating a compression piston 51, a compression space 53 provided on the head side (upper side in FIG. 1) of the compression cylinder 52, and an outer surface of the compression cylinder 52. Fins 54 for dissipating the heat of the working gas generated by the compression to the outside, the partition wall 55 provided on the drive section 20 side of the compression cylinder 52, and the insertion holes 59b formed in the partition wall 55. And a compression piston rod 58 for transmitting a driving force to the compression piston 51.

An insertion hole 59a is formed in the compression cylinder 52 and the partition wall 55 in parallel with the insertion hole 59b, and the displacer rod 35 is inserted through the insertion hole 59a.

Thus, the compression section 50 and the expansion section 30 can be arranged in the same direction, and the space occupied by the gas compression / expansion machine can be reduced.

A seal member 71 is inserted into an insertion hole 59b through which the compression piston rod 58 is inserted, and a seal member 73 is inserted into an insertion hole 59a through which the displacer rod 35 is inserted, so that oil is compressed. It does not enter the part 50 or the inflatable part 30.

Further, a gas passage G communicating with the insertion hole 59a is formed on the upper side surface of the compression cylinder 52, and gas seals 72 and 74 are provided in the compression cylinder 52 and the displacer 31, respectively.

Next, the operation of the refrigeration system based on the above configuration will be described. When the crank mechanism 22 rotates, the rotational power is transmitted to the compression piston 51 and the displacer 31 via the connecting rods 24a, 24b, etc., and the compression piston 51 reciprocates with a phase delayed by about 90 degrees with respect to the displacer 31. Get to exercise.

When the compression piston 51 moves from the bottom dead center to the top dead center, the working gas in the compression space 53 is compressed. During this time, the displacer 31 moves upward and reaches the top dead center, and then moves downward.

The working gas compressed along with the upward movement of the compression piston 51 flows through the gas flow path G and is sent to the expansion section 30 while being radiated by the radiation fins 54. When the displacer 31 moves down, the working gas passes through the cold storage material 33, exchanges heat with the cold storage material 33, and is sent to the expansion space 34.

As the displacer 31 reaches the bottom dead center, the compression piston 51 moves from the top dead center to the bottom dead center, and the working gas expands and cools down. Since the expansion process at this time is an isothermal expansion process, external heat is absorbed as much as the temperature is reduced by the expansion. That is, heat can be taken from the cold head 12.

As the compression piston 51 approaches the bottom dead center, the displacer 31 starts moving upward, the working gas passes through the displacer 31, absorbs heat from the cold storage material 33, returns to the compression space 53, and one cycle is completed.

In this cycle, the heater 41
When the heating by the control circuit 42 is not performed, the contamination P such as moisture and impurity gas mixed in the working gas flowing into the expansion space 34 is concentrated and solidified on the cold storage material portion 33 a of the cold storage material 33 on the cold head 12 side. Then, clogging occurs (see FIG. 4).

Therefore, in the present invention, a heater 41 is provided on the outer peripheral side surface of the expansion cylinder 32 on the side of the portion to be cooled, and heating is performed by the heater 41 for a certain time after the start of the refrigerating apparatus, and the working gas is contained. Contamination P with cold storage material part 3
3b, and after the heating by the heater 41 is completed, it solidifies in the cold storage material portion 33a on the part to be cooled,
The locations where impurities solidify in the cold storage material 33 are dispersed (FIG. 3).
reference).

At this time, the contaminants P dispersed and solidified in the cold storage material 33 do not significantly block the flow path of the working gas flowing between the expansion space 34 and the cold storage material 33, and Can be suppressed from increasing the pressure loss when passing through the cold storage material 33.

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.

[0044]

As described above, according to the present invention, the pressure loss of the working gas when passing through the cold storage material is prevented from increasing due to the solidification of the impurities mixed in the working gas in the cold storage material, and the refrigeration efficiency is reduced. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a Stirling refrigerator according to one embodiment of the present invention.

FIG. 2 is a detailed view of an expansion portion of FIG.

FIG. 3 is an explanatory diagram for explaining the operation of the expansion section in FIG. 1;

FIG. 4 is an explanatory diagram for explaining the operation of the expansion section in FIG. 1;

FIG. 5 is a schematic sectional view of a Stirling refrigerator applied to the description of the conventional technique.

[Explanation of symbols]

 REFERENCE SIGNS LIST 30 expansion section 31 displacer 32 expansion cylinder 33 cold storage material 34 expansion space 41 heater (heating means) 42 control circuit (control means) 50 compression section 51 compression piston 52 compression cylinder 53 compression space

Claims (2)

[Claims] 1. An expansion unit for accommodating a displacer having a cold storage material therein in a reciprocating manner in an expansion cylinder, and a driving unit for accommodating a drive mechanism for reciprocating the displacer, wherein the displacer is an expansion cylinder. A refrigerating device that reciprocates within the expansion cylinder to generate cold heat by an expansion stroke of a working gas in an expansion space formed in the expansion cylinder, wherein a heating unit provided on an outer peripheral side surface of a portion to be cooled of the expansion cylinder is provided. Control means for controlling the heating means, the control means, for a certain time after the start of the refrigerating apparatus,
A refrigerating apparatus, wherein heating is performed by the heating means. 2. A compression piston reciprocatingly reciprocatingly shifted by approximately 90 degrees with respect to the display is provided inside a compression cylinder, and a working gas in a compression space formed by the compression cylinder and the compression piston is provided. 2. The refrigerating apparatus according to claim 1, further comprising a compression section for compressing, wherein the working gas compressed from the compression section flows into the expansion space, expands the working gas, and generates cold heat.