JP2001141320A - Pulse tube refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the optimum phase of gas in a capillary. SOLUTION: A capillary 5 is designed so that an inner diameter D1 at a side of the same and connected to a pulse tube is larger than another diameter D2 at a side of the same connected to a buffer tank.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse tube refrigerator, and more particularly, to a regenerator for a compressor.
The present invention relates to a pulse tube refrigerator in which a pulse tube, a capillary, and a buffer tank are connected in series in this order.

[0002]

2. Description of the Related Art Conventionally, there is no moving part in a low temperature part,
Pulse tube refrigerators have been proposed, focusing on advantages such as little vibration in the refrigeration unit, high reliability for long-term operation, and easy operation and maintenance.

FIG. 1 is a schematic view showing an example of a pulse tube refrigerator.

In this pulse tube refrigerator, a regenerator 3, a pulse tube 4, a capillary (narrow tube) 5, and a buffer tank 6 are connected in series to a compressor 1 via a connecting tube 2.

[0005] Therefore, the capillary 5 and the buffer tank 6 function as a phase shifter, so that the phase difference between the pressure wave and the flow velocity wave can be controlled, and good refrigeration performance can be exhibited.

[0006]

However, since the inside diameter of the capillary 5 is kept constant over the entire length range, the gas in the capillary 5 does not always have an optimum phase, and the refrigeration capacity is sufficiently increased. Cannot be increased.

In addition, since the capillary 5 utilizes the resistance during the movement of the gas and the mass of the gas inside the capillary 5, it is necessary to considerably lengthen the entire length. Specifically, for example, it is necessary to set the length to about 4 m. Therefore, processing of the capillary 5 is difficult,
There is also the inconvenience of being in the way.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and a first object of the present invention is to provide a pulse tube refrigerator capable of setting a gas in a capillary to an optimum phase. It is a second object of the present invention to provide a pulse tube refrigerator that can be easily processed out of the way.

[0009]

According to a first aspect of the present invention, there is provided a pulse tube refrigerator in which a regenerator, a pulse tube, a capillary, and a buffer tank are connected in series to a compressor in this order. A tapered capillary having a large diameter on the pulse tube side and a small diameter on the buffer tank side is adopted.

According to a second aspect of the present invention, the ratio of the large diameter portion to the small diameter portion of the capillary is set to about 1.1.

According to a third aspect of the present invention, the capillary is wound around a compressor.

[0012]

According to the pulse tube refrigerator of the first aspect, a tapered capillary having a large diameter on the pulse tube side and a small diameter on the buffer tank side is adopted as the capillary.
The gas in the capillary can be set to the optimum phase, and the refrigeration capacity can be sufficiently increased. Further, since the resistance can be increased, the length of the capillary can be shortened.

According to the pulse tube refrigerator of the second aspect, since the ratio of the large diameter portion to the small diameter portion of the capillary is set to about 1.1, the same operation as the first aspect can be achieved. it can.

According to the pulse tube refrigerator of the third aspect, since the capillary is wound around the compressor, not only does the capillary not interfere, but also the capillary is cooled when the compressor is cooled. In addition, the same operation as the first or second aspect can be achieved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a pulse tube refrigerator according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic diagram showing an example of the configuration of a pulse tube refrigerator to which the present invention is applied.

In this pulse tube refrigerator, a regenerator 3, a pulse tube 4, a capillary (narrow tube) 5, and a buffer tank 6 are connected in series to a compressor 1 via a connection tube 2. The capillary 5 is set so that the inner diameter D1 on the side connected to the pulse tube 4 is larger than the inner diameter D2 on the side connected to the buffer tank 6, as schematically shown in FIG. The regenerator 3 and the pulse tube 4 are connected by a communication line formed in the cold block 8.
They are connected so as to be folded back. Also,
The cold end of the regenerator 3 and the cold end of the pulse tube 4 are supported by a wall 9 of a vacuum case.

The operation of the pulse tube refrigerator having the above configuration is as follows.

In this pulse tube refrigerator, the compressor 1
Is operated to generate a pressure wave, whereby the virtual fluid displacer in the pulse tube 4 reciprocates, and the capillary 5 and the buffer tank 6 control the phase difference between the pressure wave and the flow velocity wave. Then, cold can be generated at the low temperature end (the end on the regenerator side) and stored in the regenerator 3.

During the above-described operation, the capillary 5 has a tapered shape with a small diameter on the buffer tank 6 side, so that the resistance when the gas moves can be increased. It is possible to improve the refrigeration capacity by setting the gas inside to the optimum phase.
Further, due to the increased resistance, the overall length of the capillary 5 can be shortened, and the compact pulse tube refrigerator as a whole can be achieved.

Here, when the capillary 5 is replaced with an electric circuit, the PU phase angle θ (the phase difference between the pressure wave and the velocity wave) is tan θ = ｛(ω / ω0) ² (ωL / R )｝ / ｛1+
(ΩL / R) ² − (ω / ω0) ² ｝. Here, ω0 = 1 / (L
C) ^1/2 , ω is angular frequency, L is inductance, R is resistance, and C is capacitance.

The condition for θ> 90 ° is R ² C / L> 1.

Here, by making the capillary 5 tapered, C can be made large.

Therefore, R for satisfying R ² C / L> 1 can be reduced. In other words, the total length of the capillary 5 can be shortened.

FIG. 3 is a diagram showing a change in refrigeration capacity when the ratio of the inner diameter D1 to the inner diameter D2 is changed.
It can be seen that by setting the ratio D1 / D2 larger than 1 and smaller than 1.12, the refrigerating capacity can be increased as compared with the conventional pulse tube refrigerator.

FIG. 4 is a schematic view showing another embodiment of the pulse tube refrigerator of the present invention.

This pulse tube refrigerator differs from the pulse tube refrigerator of FIGS. 1 and 2 only in that the capillary 5 is wound around the compressor 1.

However, it is preferable that the distance from the normal temperature end of the pulse tube 4 to the start of the winding of the capillary 5 is set to a predetermined distance or more, so that the gas flow can be made smooth.

When the pulse tube refrigerator having the above configuration is employed, the same operation as that of the pulse tube refrigerator of FIGS. 1 and 2 can be achieved, and the storage space for the capillary 5 is specially prepared. This eliminates the necessity and achieves compactness as a whole. Further, since the compressor 1 is usually forcibly air-cooled, the capillary 5 can also be cooled without providing a special cooling mechanism.

[0030]

According to the first aspect of the present invention, the gas in the capillary can be set to the optimum phase, the refrigeration capacity can be sufficiently increased, and the resistance can be increased. It has a specific effect that it can be performed.

The second aspect of the invention has the same effect as the first aspect.

According to the third aspect of the present invention, not only does the capillary not interfere, but also the capillary can be cooled at the same time when the compressor is cooled, and the same effect as in the first or second aspect is obtained. Play.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a configuration of a pulse tube refrigerator to which the present invention is applied.

FIG. 2 is a nest schematically showing a configuration of a capillary.

FIG. 3 is a diagram showing a change in refrigeration capacity when the ratio of the inner diameter D1 to the inner diameter D2 is changed.

FIG. 4 is a schematic view showing another embodiment of the pulse tube refrigerator of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 3 Regenerator 4 Pulse tube 5 Capillary 6 Buffer tank 8 Cold block 9 Wall

Claims (3)

[Claims] 1. A regenerator (3) for a compressor (1),
A pulse tube refrigerator comprising a pulse tube (4), a capillary (5), and a buffer tank (6) connected in series in this order, wherein the capillary (5) has a large diameter on the pulse tube side and a small diameter on the buffer tank side. A pulse tube refrigerator characterized by being a capillary (5). 2. The pulse tube refrigerator according to claim 1, wherein the ratio of the large diameter portion to the small diameter portion of the capillary (5) is set to about 1.1. 3. The compressor (1), wherein the capillary (5) is a compressor (1).
The pulse tube refrigerator according to claim 1, wherein the pulse tube refrigerator is wound around a coil.