JPS61291872A - Refrigerator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a Stirling refrigerator that cools an infrared detection element to an extremely low temperature.

[Conventional technology]

FIG. 2 shows an example of the configuration of a conventional Stirling refrigerator. The Stirling refrigerator shown in the figure is called a split type Stirling refrigerator, and is a typical example of a Stirling refrigerator.

In FIG. 2, the split type Stirling refrigerator is broadly divided into (1) a compressor, (2) a cold finger, and a connecting pipe (3) that connects the straw.

The compressor (1) includes a cylinder (4) and a piston (5).

The piston (5) is driven by an electric motor (not shown in the figure) through a connecting rod (6) and a crank (71) to reciprocate inside the cylinder (4). ) is the cylinder head (
8) is attached, and the internal space defined by the cylinder (4), the piston (51, and the cylinder head (8) is called a compression chamber (9). The piston (5) such as the crank (71) The mechanical member to be driven is housed in the housing αO of (II), and the space inside the housing aa partitioned from the compression chamber (9) by the piston (51) is called the compression chamber αU. 41, the cylinder head (8) and the nousing (1 (I) are joined together to maintain airtightness with the outside, and the compression chamber (9) and the bulk chamber I inside are filled with, for example, helium.

It is filled with high-pressure working gas such as hydrogen. A piston ring t1 is installed on the side surface of the piston (5) to prevent the working gas from passing through the gap between the piston (5) and the cylinder (4).
z is attached. Furthermore, fins 0 are provided on the outer surface of the cylinder (4) to improve heat dissipation to the outside. The above is the configuration of the compressor (1). On the other hand, the cold finger (2) has a cylindrical low-temperature cylinder I, and has a displacer port 9 that reciprocates slidably within the low-temperature cylinder α knob.

The space inside the low temperature cylinder 0 is divided into two by the displacer port 9, and the space above the displacer haze is called a low temperature room αe, and the space below is called a high temperature room aη. A regenerator and a gas passage hole σ9 are provided inside the displacer (L), and the low temperature chamber aS and the high temperature chamber ση pass through the regenerator a8 through the gas passage hole α, and the The regenerator αυ is filled with a cold storage material such as a copper wire mesh.A seal ring is installed on the side of the displacer so that the working gas does not pass through the gap between the low temperature cylinder I and the displacer envelope S. Qυ is fitted. Front and cold finger (2
) is provided with a control cylinder and a control base, and is attached to the lower end of the front light displacer 119.
The control piston is in the high temperature chamber! ) 7) and the control cylinder @ are passed through and protrude into the control chamber (to). A seal ring (c) is attached to the control cylinder so that working gas does not pass through the gap between the control cylinder and the control piston. Each chamber of the cold finger (2) described above is filled with a high-pressure working gas such as helium or hydrogen, similarly to the pressure generator (1). The above is the configuration of the cold finger (2), and the compressor (
The compression chamber (9) of 1) and the high temperature chamber αη of the cold finger (2) communicate with each other via the connecting pipe (3).

Further, the compression chamber (9), the space inside the connecting pipe (3), the low temperature room αe, the high temperature room a, the regenerator αa, and the gas passage hole C19 are in communication with each other, and the The entire chamber is collectively called the working chamber ■.

The operation of the conventional refrigerator configured as described above will be explained. By reciprocating inside the cylinder (4), the piston (5) gives a sinusoidal wave to the gas pressure in the working chamber (2) extending from the compression chamber (9) to the cold room αe. On the other hand, since the volume of the parque chamber αD is sufficiently larger than the stroke volume of the piston (5), the internal gas pressure does not change much even when the piston (5) reciprocates.

The sealing ring attached to the control cylinder of the cold finger (2) provides almost complete sealing against short-period pressure changes such as the pressure waves in the gas in the working chamber (2), but it does not last long. Since the seal is incomplete, the gas pressure in the control chamber is maintained at approximately the average value of the gas pressure in the working chamber.

FIGS. 3 to 5 explain the operating principle of the conventional device in the order of the refrigeration cycle.

In one process of the cycle shown in Figure 3, the compressor (1
The piston (5) of No. 1 is located below in the cylinder (4), and the displacer a9 of the cold finger (2) is located above the low temperature cylinder α4. During the transition from FIG. 3 to FIG. 4, the piston (5) rises and compresses the gas in the working chamber (2). The heat generated by this compression is transferred to the cylinder (5
) is emitted to the outside from the fin α3 on the outer periphery. At the time shown in FIG. 4, the gas pressure in the working chamber (2) is greater than the gas pressure in the control chamber inlet.

The downward force generated on the control piston CI'41 by this differential pressure overcomes the static friction force of the seal rings all and (c) and begins to move the displacer α9 downward.

As shown in FIG. 5, it is moved to the lower part of the low temperature cylinder α core. With the movement of this displacer (Is), the high temperature chamber αη
The gas passes through the regenerator α boiler and moves to the cold room II3.

At this time, the cold storage material (2) filled in the regenerator αa absorbs heat from the gas passing therethrough and lowers the temperature of the gas. In the process from Figure 5 to Figure 6, the piston (5) of the compressor (1)
falls and expands the gas in the working chamber (2), and this expansion causes the temperature of the gas in the cold room αθ to further drop, absorbing heat from the surroundings of the upper part of the cold finger. This endothermic action plays a role in cooling the object to be cooled as a refrigerator. Since the pressure in the working chamber (2) decreases due to the expansion of the gas, at the time of FIG. 6, the gas pressure is higher in the control chamber @ than in the working chamber (to). The force applied upward to the control piston @ by this differential pressure overcomes the vibration and vibration force of the seal ring Qυ and @, and begins to move the displacer chamber upward, as shown in Fig. 3. Move it to the top. This displacer a! 9, the low temperature gas in the cold room aS passes through the regenerator aS, and the regenerator all
Cold heat is stored in the cold storage material (2) inside, and the gas itself flows into the high temperature room a71 while increasing in temperature. By repeating the above cycle.

Refrigeration operation is performed.

[Problem that the invention seeks to solve]

The conventional device as described above has the following problems. Since the gas-tightness of the piston rings az attached to the piston (5) of the compressor (1) is generally incomplete, leakage occurs little by little during operation of the refrigerator. That is, when the piston (5) rises and the gas pressure in the compression chamber (9) becomes higher than the gas pressure in the bulk chamber a11, the compression chamber (
9) to the bulk chamber, and conversely the piston descends to the compression chamber (
9) When the pressure in the bulk chamber is lower than the bulk chamber aυ, the bulk chamber αυ
Gas leaks from the compressor into the compression chamber (9). Here, the compression chamber (
The gas leaking from 9) to the bulk chamber 1111 has a higher density than the gas leaking from the bulk chamber to the compression chamber (9).
・For this reason, the mass flow rate of gas is larger when leaking from the compression chamber (9) to the bulk chamber (111).As a result, the pressure of the entire working chamber ■ and the bulk chamber lIυ during operation is
It shows the behavior as shown in the figure.

In the figure, (a) is the pressure in the working chamber ■, (b) is its time average value, (/ indicates the pressure in the bulk chamber T1B, and 9 is the time average value of the pressure in the working chamber @6:I) is the bulk chamber ( The pressure (c) of 111 becomes a value lower than the pressure (c) of 111, and the balance between the two is maintained.As mentioned above, the volume of the bulk chamber a9 is generally sufficiently large compared to the stroke volume of the piston (5), The pressure (c) in the bulk chamber (Ill) is almost constant or slightly pulsating, and is almost equal to the gas pressure before operation. Therefore, the time average value of the gas pressure in the working chamber (d) during operation of the cold 6IL machine. (b) is a value lower than the gas charging pressure before operation.If the compression ratio of the compressor (1) is the same, the higher the time average value of the pressure in the 9 working chambers, the more the refrigeration occurring in the cold room (le Since the amount of refrigeration increases, in order to obtain the required amount of refrigeration, it is necessary to fill the refrigerator with gas at a pressure higher than the average gas pressure in the working chamber (to) during operation. However.

If the gas filling pressure is increased, it is necessary to increase the pressure resistance of the housing α0, etc., resulting in an increase in weight. Furthermore, helium gas, which is commonly used as zero working gas, has small molecules, so it is difficult to keep it sealed at high pressure for long periods of time. Requires more frequent gas refills when used or stored.

This leads to the problem of deteriorating the maintenance and operability of the refrigerator.

The present invention was made to solve this problem, and proposes a refrigerator in which the time average pressure in the working chamber (to) is high during operation even when the gas filling pressure is low.

[Means for solving problems]

The refrigerator according to the present invention has a gas passage that communicates the nine working chambers with the bulk chamber of the compressor, and a check valve that allows gas to flow only from the bulk chamber toward the working chamber in the middle of the gas passage. It is prepared.

[Effect]

In this invention, when the gas pressure in the bulk chamber is higher than that in the first working chamber during refrigeration operation, gas flows from the bulk chamber into the working chamber through the check valve.

Ultimately, operation is always performed with the gas pressure in the working chamber higher than in the bulk chamber, so it is possible to lower the gas filling pressure than in conventional devices.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention.

In the figure, (l) to (2) are exactly the same as the conventional device shown in FIG. The fin is a gas flow path, and the gas flow path connects the working chamber (to) and the bulk chamber ttn.

A check valve (c) is provided in the middle of the gas flow path (c). The check valve (■) connects the bulk chamber aυ to the working chamber (■).
It is equipped to allow gas to pass in one direction, but not to pass gas in the opposite direction.

In the refrigerator of the present invention constructed as described above, the principle of generating refrigeration is exactly the same as that of the conventional apparatus shown in FIGS. 2 to 6. However, during operation, if the gas pressure in the working chamber ω is lower than the gas pressure in the bulk chamber αB, the reverse valve ■ opens and gas flows from the bulk chamber (Ill) into the working chamber (to). When the gas pressure in chamber (2) is higher than that in bulk chamber a11, the check valve (to) is closed, so that no gas movement occurs.

Therefore, ultimately, as shown in Figure 8, one working chamber ■
The gas pressure q) repeats sinusoidal wave motion at a position always higher than the pressure (c) in the bulk chamber a11.

The pressure (c) in bulk chamber I during operation is the same as that of the conventional device.

Almost equal to the gas filling pressure before starting operation. therefore,
This is because the refrigerator according to the present invention can obtain the same pressure wave with a lower gas filling pressure than the conventional device.

Since the pressure resistance of the housing (Ie, etc.) is relatively unnecessary, the weight of the compressor (1) can be reduced.Furthermore, the lower the gas filling pressure, the less the amount of gas leaking from the refrigerator to the outside, so it can be used for a long period of time. When using or storing a refrigerator,
There is an advantage in terms of maintenance and operation that the frequency of gas refilling can be reduced.

Incidentally, in the above description, the present invention has been described with respect to a split type Stirling refrigerator, but it goes without saying that the present invention can also be applied to other known Stirling refrigerators.

〔Effect of the invention〕

This invention has a simple structure that includes a gas flow path connecting the working chamber and the bulk chamber, and a check valve in the middle of the gas flow path. Since an average pressure can be obtained, it is possible to reduce the weight of parts that require pressure-resistant strength such as the housing, and at the same time, the lower the gas sealing pressure, the less gas leaks to the outside of the refrigerator, so it can be used for a long time. This has the effect of reducing the need for replenishment of one working gas during storage, and significantly improving the maintainability and operability of the refrigerator.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIGS.
The figure shows a conventional refrigerator, FIG. 7 shows temporal changes in working chamber pressure and bulk chamber pressure in a conventional refrigerator, and FIG. 8 shows working chamber pressure in a refrigerator according to the present invention. and FIG. 7 is a diagram showing temporal changes in pressure in the bulk chamber. In the figure, (4) is a cylinder, (5) is a piston, (
8) is the cylinder head, (9) is the compression chamber, and αυ is the housing. αυ is the bulk chamber, (Ie is the cold chamber, ag is the regenerator, c!
n is a cold storage material, ■ is an operating chamber, @ is a gas flow path, and (to) is a check valve.In addition, the same or equivalent parts in Figure 1 are indicated with the same reference numerals.

Claims (1)

[Claims] a cylinder having a cylindrical inner peripheral surface; a housing to which the cylinder is attached and having a space therein; a cylinder head that closes one end surface of the cylinder; a piston that reciprocates within the cylinder; A compression chamber partitioned by the cylinder head and the piston, a bulk chamber partitioned by the cylinder, the housing, and the piston, a cold room that generates refrigeration and absorbs heat from the outside, and a cold storage material inside. a storage regenerator; a working chamber containing the compression chamber, the regenerator, and the cold room; a gas passage connecting the working chamber and the bulk chamber; and a check valve provided in the gas passage. A refrigerator characterized by comprising: