JPH01147263A - Refrigerator - Google Patents

Abstract

PURPOSE: To judge instantly a cause of poor performance by checking whether a movement of a displacer is appropriate when an abnormality occurs in the performance of a refrigerating machine. CONSTITUTION: A magnet 26 installed on an end section of a control piston 24 is integrated with a displacer 15. Thus, it is possible to know a position and a movement of the displacer 15 by providing a magnetic sensor 27 on the outside of a control room 23. Namely, magnetism generated by the magnet 26 is strong when the displacer is positioned on the side of a high temperature room 17, and magnetism generated by the magnet 26 is weak when the displacer 15 is positioned on the side of a low temperature room. By detecting the intensity of the magnetism by the magnetic sensor 27, the position and the movement of the displacer 15 are detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a Stirling refrigerator that cools, for example, an infrared detection element or a superconductor 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 roughly divided into (1) a compressor, (2) cold fingers, and a connecting pipe (3) that connects them.

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

Although not shown in the drawings, the piston (5) is driven by an electric motor to reciprocate inside the cylinder (4) via a connecting rod (6) and a crank (7). A cylinder head (
The internal space partitioned by the cylinder (4), the piston (51 and the cylinder head (8)) is called a compression chamber (9). 5) is housed in a housing (10), and the housing (10) is partitioned from the compression chamber (9) by the piston (5).
The space within 1 is called the bulk chamber circle. the cylinder (4);
The cylinder head (8) and the housing (10
) if: They are joined to each other so as to maintain airtightness with the outside, and the compression chamber (9) and the bulk chamber circle inside are filled with, for example, helium.

It is filled with high-pressure working gas such as hydrogen. A piston ring (1) is provided on the side surface of the piston (5) to prevent working gas from passing through the gap between the piston (5) and the cylinder (4).
2) is installed. Furthermore, fins (13) are provided on the outer surface of the cylinder (4) to enhance heat dissipation to the outside. The above is the configuration of the compressor (υ). On the other hand, the cold finger (2) has a cylindrical low-temperature cylinder ring, and has a displacer a51' that reciprocates slidably around the low-temperature cylinder.

The space inside the low temperature cylinder circle is the displacer α
The space above the displacer (151 is called a low temperature room a6) and the space below is called a high temperature room aη. A regenerator α mark and a gas passage hole α0 are provided inside the displacer Q51, and the low temperature chamber 1
6), the high temperature chamber α71U, the regenerator, and the gas passage hole α9). The low temperature cylinder circle and the displacer (15
A seal ring (211) is fitted into the side of the displacer so that the working gas does not pass through the gap 1. A control chamber (c) is provided at the bottom of the cold finger (21) for the control cylinder. , the control piston attached to the lower end of the displacer (15) connects the high temperature chamber aη and the control cylinder (221').
The through hole protrudes into the control room. A seal ring is attached to the control cylinder to prevent working gas from passing 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, similar to the compressor (υ).The above is the configuration of the cold finger (2), and the compressor (1
) and the high temperature chamber (17) 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 chamber +161, the high temperature chamber aη, the regenerator αQ, and the gas passage hole α91I′i communicate with each other, and these chambers The whole is collectively called the working chamber (4).

The operation of the conventional refrigerator configured as described above will be explained. By reciprocating inside the hash ring (4), the piston (5) gives a sinusoidal wave to the gas pressure in the working chamber (□□□) from the compression chamber (9) to the cold room. On the other hand, the volume of the bulk chamber UU is sufficiently larger than the stroke volume of the piston (5), so the internal gas pressure is lower than that of the piston (5).
Even if it makes a reciprocating motion, it does not change much.

The seal ring (25) attached to the control cylinder of the cold finger (2) is connected to the aforementioned working chamber (support).
) The control room c! 3) The gas pressure in the working chamber (5) is maintained at approximately the average value of the gas pressure in the working chamber (5).

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 the cold finger (2) is located below in the cylinder (4), and the displacer a5 of the cold finger (2) is located above the low temperature cylinder Q41. Figures 3 to 4
While reaching the figure, the piston (5) rises and the working chamber (support)
compress the gas. The heat generated by this compression is released to the outside from the fins on the outer periphery of the cylinder (4). At the time of FIG. 4, the gas pressure in the working chamber (26) is greater than the gas pressure in the control chamber (23).

The downward force generated on the control piston due to this differential pressure overcomes the static friction force of the seal ring and (c) and begins to move the displacer α51 downward.

As shown in FIG. 5, the gas in the high temperature chamber 0η is moved to the lower part of the low temperature cylinder circle. As the displacer αω moves, the gas in the high temperature chamber 0η passes through the regenerator 18) and moves to the low temperature chamber Q61.

At this time, the regenerator ugI is filled with cold storage material (a)
absorbs heat from the passing gas and lowers the overall gas temperature.

In the process from Fig. 5 to Fig. 6, the piston (5) of the compressor (1) descends and expands the gas in the working chamber (□□□), and this expansion causes the gas in the cold room (16) to further rise in temperature. It descends and absorbs heat from the surrounding area above 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 (support) decreases due to the expansion of the gas, the gas pressure is lower in the control chamber (23) than in the working chamber (06) at the time of FIG. The force applied upward to the control piston due to this differential pressure overcomes the static frictional force of the seal ring (211 and (a)) and begins to move the displacer 05 completely upward, causing the third
As shown in the figure, move it to the upper part of low temperature cylinder a (a). As this displacer Q powder moves, the cold room (1
The low-temperature gas (6) passes through the regenerator (11, and stores cold heat in the cold storage material (1) in the regenerator α8), and the gas itself flows into the high temperature room aη while increasing its 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. That is, the displacer (151).

Since there is no mechanical connection with the drive source, the displacer α5)
It is not possible to know the position of the displacer 09 or the movement of the displacer 09 during operation of the refrigerator. The problem is that, for example, the displacer α9 does not move properly due to damage or wear of the seal ring (211 or (support)).

If the refrigerator no longer provides the specified performance.

This means that there is no way to determine the cause of the lack of performance.

The present invention has been made to solve such problems,
A means is provided for determining whether or not the displacer (151) is moving appropriately.

[Means for solving problems]

In the refrigerator according to the present invention, at the end of the control piston (to),
A magnet is attached to detect the position of the displacer α9.

[For production]

The refrigerator according to the present invention has a display laser α5 by attaching a magnet to the end of the control piston.
) can be known by attaching a magnetic sensor to the outside of the cold finger (2). As a result, if there is an abnormality in the performance of the refrigerator, it is checked whether the movement of the displacer (15) is appropriate, and if there is an abnormality in this, the cause of the poor performance can be immediately determined.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

In the figure, all parts of the refrigerator are the same as the conventional device except that a magnet is attached to the end of the control piston.

The magnet (support) in the present invention is integrated with the displacer (15). Therefore, by installing a magnetic sensor @ outside the control room (c), the displacer 0
5) The position and movement of the object can be known. That is,
When the displacer is located on the αη side of the high temperature room, the magnetism generated by the magnet □□□) is strong, and the displacer 05)
When the is located on the side of the cold room, the magnetism emitted by the magnet is weak. By detecting the strength of this magnetism with a magnetic sensor @, the position and movement of the displacer α5) can be detected.

〔Effect of the invention〕

As described above, according to the present invention, the movement of the displacer a9 can be detected. As a result, if an abnormality occurs in the performance of the refrigerator, it can be immediately determined whether the movement of the displacer α clause is appropriate, and the work to investigate the cause of the abnormality in the performance of the refrigerator can be carried out efficiently. can.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIGS. 2 to 6 are diagrams showing a conventional refrigerator. In the figure, (1) is the compressor, and (2) is the cold finger. (3) C connecting pipe, (151 is displacer, Foundation)
indicates the control piston, @) indicates the magnet, and @ indicates the magnetic sensor. Note that the same or corresponding parts in FIG. 9 are designated by 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 inside, a cylinder head that closes one end surface of the cylinder, a piston that reciprocates in the cylinder, and 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 low-temperature cylinder that absorbs heat from the outside at one end; and a displacer that reciprocates within the low-temperature cylinder. a low temperature chamber partitioned by one end of the low temperature cylinder and the displacer to generate refrigeration; a high temperature chamber partitioned by the other end of the low temperature cylinder and the displacer; and one end of the high temperature side of the displacer. a control piston that receives a gas pressure difference and transmits it as a driving force to the displacer;
A refrigerator characterized in that a magnet for detecting the position of the displacer is provided at an end of the control piston.