JPH08320164A - Stirling refrigeration equipment - Google Patents

Abstract

(57) [Summary] [Purpose] Even when outside air enters the freezer, the temperature rise is avoided. [Structure] A Stirling engine 1 has a thermal cycle process including at least an expansion process of a working gas introduced from a compression chamber 3 formed in a front part of a compression cylinder part 2a to an expansion chamber 5 formed in a front part of an expansion cylinder part 4a. Generates cold heat. The heat conducting portion 18 is formed at the tip of the expansion cylinder portion 4a connected to the expansion chamber 5 and conducts the heat of cold generated in the expansion chamber 5. The freezing box 10A forms a freezing compartment 15 in which the inner wall 12 is covered with a heat conduction plate to accommodate a refrigeration load, and a heat conduction part 18 is projectingly provided in the freezing compartment 15 while a refrigeration load is placed on the mounting shelf. Are installed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a Stirling refrigerating apparatus for realizing an ultra-low temperature state in a freezer box by using a Stirling engine.

[0002]

2. Description of the Related Art A refrigeration system using a Stirling engine is relatively easy to maintain, and absorbs heat when the working gas expands to cool the interior of the refrigeration box from -60 ° C to an ultra-low temperature of about -200 ° C to freeze blood, chemicals, etc. It is suitable for cooling products to ultra-low temperature and is about to be widely used in various fields.

FIG. 3 is a partial cross-sectional view showing the inside of a Stirling refrigerating apparatus of this type.
Has a compression chamber 3 for compressing the working gas in front of the first piston 2 fitted in the compression cylinder part 2a, while expanding the working gas in front of the second piston 4 fitted in the expansion cylinder part 4a. The compression chamber 3 and the expansion chamber 5 are connected to each other through a gas flow path with a heat regenerator and a radiator (not shown) interposed therebetween, and the first piston 2 and the second piston 4 is configured to reciprocate by a crank mechanism 7 powered by a prime mover with a certain phase difference.

On the other hand, the freezing box 10 is arranged above the Stirling engine 1, and a heat insulating material 13 such as urethane is filled between the box-shaped outer box 11 and the inner box 12, and the inner peripheral wall of the inner box 12 is filled. Is attached to the side wall as the heat conducting plate 14a while having a good heat conduction, while the bottom wall is provided with the heat conducting plate 14b.
A freezing chamber 15 for accommodating an item to be frozen as a refrigerating load is formed on the inner side surrounded by the heat conduction plates 14a and 14b. A lid 16 for taking in and out is provided.

Further, the freezing box 10 has a heat conducting portion 18 connected to the tip of the expansion cylinder portion 4a at the bottom thereof,
One end of the heat conducting portion 18 is connected to the tip of the expansion cylinder portion 4a, while the other end thereof is joined to the bottom surface of the heat conducting plate 14b.

With the above construction, when the prime mover is driven, the crank mechanism 7 causes the first piston 2 and the second piston 4 to reciprocate with a certain phase difference.

First, the first piston 2 moves and the compression chamber 3
The working gas, such as helium, which fills the space is compressed, and the compressed and heated working gas is radiated by a radiator (not shown) and further cooled by a heat regenerator (not shown) before being introduced into the expansion chamber 5. After that, the working gas in the expansion chamber 5 expands due to the lowering of the second piston 4, the working gas expands to lower the working gas temperature, cools the heat conducting portion 18, and subsequently, the second piston 4 Expansion chamber 5
The low-temperature working gas is extruded and introduced into the compression chamber 3 while cooling the heat regenerator.

The above steps are repeated in sequence, and the working gas in the expansion chamber 5 expands when the heat conducting portion 18 of the expansion cylinder portion 4a is expanded.
The heat conduction part 18 to cool the heat conduction plate 14
The freezing chamber 15 of the freezing box 10 is gradually lowered in temperature via a and 14b, and by repeating this, the upper portion of the heat conducting portion 18 of the expansion cylinder portion 4a is brought to a temperature of about -200 ° C. In the freezer compartment 15, freezing heat is transmitted from the heat conducting portion 18 via the heat conducting plate 14b, and the central portion thereof has a temperature of about -180 ° C.
And Further, the freezing heat is transmitted from the heat conducting portion 18 through the heat conducting plate 14b to the periphery of the freezing chamber 15 by the heat conducting plate 14a, and is set to about -170 ° C lower than the central portion.
As a result, frozen objects such as blood, drugs and various bacteria can be stored in the freezer compartment 15 at an ultralow temperature.

[0009]

By the way, in the conventional Stirling refrigerating apparatus shown in FIG. 3, when the lid 16 is opened to take out the refrigerating load from the freezing chamber 15 or put the refrigerating load into the freezing chamber 15, the inside of the freezing chamber 15 is closed. There is a problem that the temperature rises sharply and it takes a lot of time to return to the freezing temperature again.

That is, the freezing temperature is normally about -180.degree. C. in the lowest part of the freezing chamber 15 in normal times, and if the lid 16 is opened, warm air of about 20.degree. The freezing heat in the chamber 15 is removed and the freezing chamber 1
Although the temperature in 5 rapidly rises, it is quite necessary to return the freezing chamber 15 to the freezing temperature again by heat conduction from the heat conducting portion 18 through the heat conducting plates 14b and 14a by the action of the Stirling engine 1. However, the refrigeration load may be affected during this period.

Therefore, an object of the present invention is to provide a Stirling refrigerating apparatus which prevents the temperature in the freezing chamber from rapidly rising and always maintains the internal temperature.

[0012]

According to a first aspect of the present invention, an expansion stroke of a working gas introduced from a compression chamber formed in a front portion of a compression cylinder portion to an expansion chamber formed in a front portion of an expansion cylinder portion is controlled. A Stirling engine that generates cold heat by a heat cycle process that includes at least a heat conducting portion that is formed at the tip of the expansion cylinder portion and that conducts the cold heat generated in the expansion chamber, and a refrigerating load whose inner wall is covered with a heat conducting plate. In a Stirling refrigerating device having a freezing box forming a freezing chamber for storing the heat, a heat conduction part for liquefying the gas in the freezing chamber is projected into the freezing chamber, while a mounting shelf for mounting a refrigeration load is thermally conducted. It is arranged above the part.

[0013]

According to the structure of the present invention, the freezing heat from the heat conducting portion projecting in the freezing chamber gradually liquefies the air in the freezing chamber so that the liquid air stays at the bottom of the freezing chamber.
In this state, if the outside air is temporarily mixed into the freezing compartment, the liquid air in the freezing compartment is vaporized by the outside air, rises, and is gradually released to the outside. During this time, it is possible to avoid affecting the refrigerating load of the loading rack without causing the freezing room temperature to rise sharply.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are schematic sectional views of a Stirling refrigerating apparatus showing an embodiment of the present invention, in which the same reference numerals as those of FIG. 3 showing a conventional example indicate the same or corresponding portions, and FIG. 2 is equipped with a freezing box 10A having a different configuration from the freezing box 10 shown in FIG.

Specifically, the freezing box 10A is arranged above the Stirling engine 1, and a heat insulating material 13 such as urethane is filled between the box-shaped outer box 11 and the inner box 12 to form the inner box 12. On the inner peripheral wall, a plate having a predetermined thickness with good heat conduction is attached to the side wall as the heat conducting plate 14b, while the bottom wall is attached with the heat conducting plate 14a, and the inner side surrounded by the heat conducting plates 14a and 14b is provided. Is formed with a freezer compartment 15 having a placing shelf 17 on which the frozen goods as a refrigerating load are placed, and a lid 16 for loading and unloading the frozen goods is provided at the front opening of the freezing compartment 15. In addition, 6 shown in FIG. 2 is a prime mover for driving the crank mechanism 7.

Further, in the freezing box 10A, a tip of a heat conducting portion 18, which is a cold head for conducting cold heat from the Stirling engine 1, is provided at a lower portion of the freezing box 10A so as to project from a bottom portion of the freezing chamber 15. The end is the expansion cylinder 4a
Connected to the tip of

With the above construction, first, the first piston 2 moves to compress the working gas such as helium which fills the compression chamber 3. The compressed and heated working gas is radiated by a radiator (not shown). It is further cooled by a heat regenerator (not shown) and then introduced into the expansion chamber 5. After that, the working stroke of the working gas in the expansion chamber 5 is expanded by the lowering of the second piston 4, and the working gas is cooled by the expansion of the working gas,
The heat conducting portion 18 is cooled, and subsequently, the rise of the second piston 4 pushes out the low-temperature working gas in the expansion chamber 5 and guides it to the compression chamber 3 while cooling the heat regenerator. The above process is sequentially repeated so that the working gas in the expansion chamber 5 cools the heat conducting portion 18 of the expansion cylinder portion 4a during expansion.

At this time, the radiation fins 18 of the heat conducting portion 18
The cold heat is released from a into the freezing compartment 15, and the entire interior is gradually cooled through the heat conducting plates 14a and 14b to lower the temperature inside the freezing compartment 15. Further, as time passes, the air in the freezer compartment 15 is liquefied, and the liquefied liquid air is retained at the bottom of the freezer compartment 15.
In this state, a refrigerating load is placed on the placing shelf 17 to store blood, drugs, various bacteria and the like.

On the other hand, the lid 16 is used when the refrigerating load placed on the placing shelf 17 is taken out or is newly stored.
Is opened. As a result, warm outside air is mixed into the freezer compartment 15 all at once through the opening, but the liquid air staying at the bottom of the freezer compartment 15 is vaporized and moves to the upper part via the net-shaped mounting shelf 17. While the liquid air is gradually vaporizing, the freezer compartment 15
The temperature inside does not rise and is maintained at the freezing temperature. Therefore, the refrigerating load placed on the placing shelf 17 is not adversely affected, and there is no need to wait for the recovery time to reach the freezing temperature as in the conventional case. further,
There is no need to replenish the freezing chamber 15 with liquid nitrogen from the cylinder as in the conventional case.

[0021]

As described above, according to the present invention, the heat conducting portion is provided in the freezing chamber so that the air in the freezing chamber is liquefied and the liquid air is retained in the freezing chamber. Even if the outside air is temporarily mixed, it is possible to avoid affecting the refrigerating load of the mounting shelf without causing the temperature of the freezing room to rise sharply.

[Brief description of drawings]

FIG. 1 is a front sectional view of a Stirling refrigerating apparatus showing an embodiment of the present invention.

FIG. 2 is a side sectional view of a Stirling refrigeration system showing an embodiment of the present invention.

FIG. 3 is a front sectional view of a Stirling refrigerating apparatus showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stirling engine 2 1st piston 3 Compression chamber 4 2nd piston 5 Expansion chamber 6 Motor 7 Crank mechanism 10A Refrigerating box 11 Outer box 12 Inner box 13 Insulating material 14a, 14b Heat conduction plate 15 Freezing room 16 Lid 17 Mounting shelf 18 Heat conduction part

Claims (1)

[Claims] 1. A Stirling device that generates cold heat by a heat cycle process including at least an expansion process of a working gas introduced from a compression chamber formed in a front part of a compression cylinder part to an expansion chamber formed in a front part of an expansion cylinder part. An engine, a heat conduction part formed at the tip of the expansion cylinder part for thermally conducting the cold heat generated in the expansion chamber, and a freezing box forming a freezing chamber in which an inner wall is covered with a heat conduction plate to accommodate a refrigeration load. In a Stirling refrigerating apparatus including: a heat conduction part for liquefying a gas in the freezing chamber is provided to project into the freezing chamber, and a mounting shelf for mounting the refrigeration load is arranged above the heat conduction part. A Stirling refrigerating device.