JP2002048425A - Pulse tube refrigerating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pulse tube refrigerating machine having economical predominance. SOLUTION: An upper part side of a cold storage unit 20 for constituting a compressor 30, a cylinder 31 and a second pulse tube 33 are connected in series with each other. An end of a second pulse tube 33 at the unit 20 side is cooled by a cooler 34, a piston 32 in the cylinder 31 is driven to function the overall compressor 30 as a thermal compressor. Accordingly, a load to be received at a reciprocating time of the piston 32 in the cylinder 31 can be set to only a contact resistance with the cylinder 31 receiving via a sealing member 321. Thus, a power consumption of a motor for driving the piston 32 can be extremely reduced, a wear of the component for driving the piston 32 is suppressed, and thus a labor hour for frequently conducting a maintenance can be omitted, and hence is economic.

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, for example, a pulse tube refrigerator used for a cryopump or the like.

[0002]

2. Description of the Related Art Conventionally, a pulse tube refrigerator including a pulse tube, a regenerator connected to a low temperature side of the pulse tube, and a compressor connected to a high temperature side of the regenerator has been known. . In such a pulse tube refrigerator, a high-pressure valve and a low-pressure valve provided between the regenerator and the compressor are opened and closed substantially alternately to generate pressure oscillation in the pulse tube. A buffer (reservoir tank) is connected to the high-temperature side of the pulse tube via an orifice. In addition, a flow path between the orifice and the pulse pipe and a flow path between the regenerator and the compressor are connected to another orifice. By connecting via a bypass flow path having a (double inlet type), the phase difference between the pressure vibration in the pulse tube and the displacement of the gas column (virtual gas piston formed in the pulse tube) in the pulse tube is improved. To improve the refrigeration efficiency.

[0003]

However, as a compressor used in a conventional pulse tube refrigerator, there is a compressor having a drive unit driven by a motor, such as a reciprocating type, a screw type, a rotary type, and a scroll type. Because of the large load on the drive unit during the operation of the pulse tube refrigerator, the power consumption of the motor is large, and the drive unit is liable to wear out, requiring frequent maintenance. There is a problem that there is.

An object of the present invention is to provide a pulse tube refrigerator which is economically superior.

[0005]

A pulse tube refrigerator according to the present invention has a pulse tube, a regenerator connected to a low temperature side of the pulse tube, and a regenerator connected to a high temperature side (room temperature side) of the regenerator. A pulse tube refrigerator including a compressor, wherein the compressor has another pulse tube and another regenerator each having one end connected in parallel to the regenerator, and these other pulse tubes and A cylinder connected in series between the other ends of the other regenerators, and a mechanically driven piston is provided in the cylinder, and the one end of the another pulse tube is provided. Is maintained at a lower temperature than the one end of the cylinder.

According to this invention, another pulse tube, another regenerator and a cylinder constituting the compressor are connected in series, and one end of the another pulse tube on the regenerator side is connected to the cylinder. This compressor functions as a thermal compressor by driving a piston in a cylinder to make the temperature lower than one end of the compressor. Therefore, the load that the piston receives when reciprocating in the cylinder is only the contact resistance with the cylinder, and the power consumption of, for example, a motor that drives the piston is extremely small. It is suppressed and maintenance is not required frequently, so that it is more economical than before.

[0007] In the pulse tube refrigerator of the present invention, it is desirable that the regenerator and another regenerator constituting the compressor be provided integrally. In such a configuration, the arrangement space is smaller than when each regenerator is individually arranged, and the miniaturization of the pulse tube refrigerator is promoted.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, a pulse tube refrigerator 1
Is a first pulse tube 10, a regenerator 20 connected to the low temperature side of the pulse tube 10, and a high temperature end (room temperature end) of the regenerator 20.
A cylinder 31 having one end connected to the side thereof;
A second pulse tube 33 having one end connected to the middle of the regenerator 20;
And a buffer tank 40 connected to the high-temperature end of the first pulse tube 10.
A cold (heat) station that generates an extremely low temperature is formed by the portion of the flow path 81 that connects the pulse tube 10 and the regenerator 20.

In this embodiment, the high-temperature side of the regenerator 20 (high-temperature side with respect to a connecting portion of a flow path 82 described later), the cylinder 31, the piston 32, and the second pulse tube 3
3, and the cooling device 34 form the compressor 30 according to the present invention.

In the first pulse tube 10, a gas column 11 (gas column: shown by a dotted line) is virtually formed by a working gas such as helium. This gas column 11 is a pulse tube 1
It reciprocates up and down in FIG.

The regenerator 20 is formed, for example, by punching a mesh made of a copper wire in a mesh shape into a disk shape and stacking a plurality of such disk-shaped nets in a metal cylinder. In some cases, spheres such as lead may be additionally filled as necessary. In the regenerator 20, one end of the second pulse tube 33, that is, the low-temperature end cooled by the cooling device 34 is connected via a flow path 82 in the middle of the flow direction of the working gas.

In the compressor 30, the cylinder 31, the pulse tube 33, and the high-temperature side of the regenerator 20 communicate with the flow paths 82, 8.
3, 84 in series, of which the lower end side of the pulse tube 33 in the figure and the high temperature side of the regenerator 20 are:
The regenerator 20 is connected in parallel to the low-temperature side (the low-temperature side with the connecting portion of the flow path 82 as a boundary).

In the cylinder 31, a pulse tube side communication chamber 311 is formed on the side of the flow path 84, ie, on the side of the second pulse tube 33, with the piston 32 as a boundary, and on the side of the flow path 83, ie, on the side of the regenerator 20. A regenerator-side communication chamber 312 is formed. The cylinder 31 has a piston 3 (not shown).
There is provided a seal member for ensuring airtightness with the rod connected to 2.

The piston 32 is driven by a motor, such as a rod and a crank (not shown). A seal member 321 such as an O-ring is attached to an outer peripheral portion of the piston 32 to reliably block leakage of working gas between the communication chambers 311 and 312 in the cylinder 31. In such a piston 32, each of the communication chambers 311 and 312 has a flow path 83,
Since the working gas is communicated with the other through the communication valve 84, the working gas can reciprocate without being compressed in the communication chambers 311 and 312, and reciprocates except for frictional resistance generated between the seal member 321 and the cylinder 31. The displacer receives almost no load during operation.

The second pulse tube 33 has a larger diameter than the first pulse tube 10 but a smaller length. A gas column 331 (gas column: shown by a dotted line) is virtually formed in the second pulse tube 33 by the working gas. This gas column 331 reciprocates up and down in the drawing in the pulse tube 33. The lower end of the pulse tube 33 is cooled by the cooling device 34, but the upper end is maintained at, for example, about room temperature.

As the cooling device 34, a cooling device in which a tube in which a refrigerant or the like circulates is brought into contact with the lower end of the pulse tube 33 or the like or a cooling device having any other structure can be used.

The buffer tank 40 is generally used for a pulse tube refrigerator. The buffer tank 40 communicates with the first pulse tube 10 via a flow path 85, and an orifice 851 is provided in the flow path 85. I have. Also, this orifice 8
On the pulse tube 10 side of 51, the flow path 85 and the flow path 83 communicate with each other via a bypass flow path 86, and an orifice 861 is provided in the middle of the flow path 86. That is, the buffer tank 40, the orifices 851 and 861, the first pulse tube 1
0 and the regenerator 20 have substantially the same structure as that of a conventional so-called double inlet type pulse tube refrigerator.

The pulse tube refrigerator 1 according to the present embodiment as described above.
In the above, refrigeration occurs as follows. First, in the cylinder 31 of the compressor 30, when the piston 32 is at the end on the flow path 84 side, the gas column 331 in the second pulse tube 33 is located on the lower cooling end side, and the first pulse Tube 1
The gas column 11 in 0 is also located on the low temperature side at the lower end. And
The working gas in the regenerator-side communication chamber 312 of the cylinder 31 has a high pressure.

In this state, when the piston 32 is moved to the flow path 83 and the high-pressure working gas is sent out from the regenerator-side communication chamber 312, most of the working gas passes through the upper part of the regenerator 20 and then passes through the flow path. The second larger diameter through the second 82
Into the lower end of the pulse tube 33. At this time, the working gas is cooled by the cooling device 34 to a low pressure, and the gas column 331 is pushed upward by the low-pressure working gas, and the room temperature level working gas originally existing above the gas column 331 is removed. It enters the pulse tube side communication chamber 311 in the cylinder 31 via the flow path 84.

On the other hand, the remaining working gas sent out from the regenerator-side communication chamber 312 passes through the regenerator 20 to the end, and then enters the low-temperature side of the pulse tube 10 through the flow path 81 and passes through the gas column 11. At the same time as being pushed upward, the flow path 86
The flow rate is adjusted by the orifice 861 from the
Flows into the hot side of. Accordingly, the working gas originally present on the higher temperature side than the gas column 11 in the pulse tube 10 and the working gas flowing from the orifice 861 are mixed, and the flow rate is adjusted by the orifice 851 through the flow path 85. Into the buffer tank 40.

Next, at this time, the piston 32 is
The working gas at the room temperature level in the pulse tube side communication chamber 311 returns to the second pulse tube 33 side and returns to the second pulse tube 33 side.
The low-pressure and low-temperature working gas that has entered the pulse tube 33 through the flow path 82 is deprived of cold heat at the upper side of the regenerator 20 and then gradually increases in pressure to become a regenerator in the cylinder 31. It returns to the inside of the side communication room 312. That is, the cylinder 31,
The compressor 30 formed including the piston 32 and the second pulse tube 33 functions as a thermal compressor.

In the process in which the piston 32 returns to the flow path 84, the working gas that has entered the buffer tank 40 is discharged, and a part of the working gas returns to the flow path 83 through the flow path 86.
The remainder returns to the pulse tube 10 as the high-temperature side gas of the gas column 11. At this time, the gas column 1 in the first pulse tube 10
The high-pressure working gas that has entered the low-temperature side than 1 adiabatically expands to generate refrigeration, cools the flow path 81, and cools the regenerator 20.
, Low heat is stored in the regenerator 20.
Then, the working gas, which has become low pressure after being adiabatically expanded, gradually rises in temperature after passing through the regenerator 20, and the regenerator-side communication chamber 31
Return to 2.

Thus, one cycle of the pulse tube refrigerator 1 is completed. Then, in the next cycle, the high-pressure working gas that has passed through the regenerator 20 to the first pulse tube 10 and has received the low heat stored in the regenerator 20 has a lower temperature. Get into it. After this,
The low-temperature working gas adiabatically expands to generate lower-temperature refrigeration, thereby further lowering the temperature of the flow path 81. By repeating such a cycle, the flow path 8
The cold station formed in 1 finally reaches a very low temperature.

According to this embodiment, the following effects can be obtained. That is, the upper side of the regenerator 20 constituting the compressor 30, the cylinder 31, and the second pulse tube 33 are connected in series, and the end of the second pulse tube 33 on the regenerator 20 side is a cooling device. Since the cooling is performed at 34, the entire compressor 30 can function as a thermal compressor by driving the piston 32 in the cylinder 31. Therefore, the load that the piston 32 receives when reciprocating in the cylinder 31 can be limited to the contact resistance with the cylinder 31 that is received via the seal member 321, and the power consumption of, for example, a motor that drives the piston 32 is extremely small. In addition to this, it is possible to save the trouble of frequently performing maintenance by suppressing wear of parts for driving the piston 32, and the cost is more economical than that of the related art.

In the pulse tube refrigerator 1, the compressor 30
Since the regenerator and the regenerator directly required for generating refrigeration are integrally provided by the regenerator 20, the arrangement space can be made smaller than when each regenerator is individually arranged, and the pulse tube The refrigerator 1 can be downsized.

It should be noted that the present invention is not limited to the above-described embodiment, but includes other configurations that can achieve the object of the present invention, and the following modifications are also included in the present invention.
For example, in the above-described embodiment, the lower end of the second pulse tube 33 is cooled by the cooling device 34. However, the present invention that cools one end of the second pulse tube 33 includes a case where the flow path 82 is cooled. Is also included. Further, in addition to cooling the end portion of the second pulse tube 33, a temperature difference from the second pulse tube 33 may be generated by heating the end portion of the cylinder 31 on the flow channel 83 side. Even in such a case, the compressor 30 functions as a thermal compressor, and the object of the present invention can be achieved.

Further, in the above-described embodiment, the structure on the side of the first pulse tube 10 is a conventional double-inlet type.
And the buffer tank 40 may be simply connected to each other by the flow path 85, and the structure is arbitrary.

[0028]

As described above, according to the present invention,
There is an effect that an economically advantageous pulse tube refrigerator can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a pulse tube refrigerator according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pulse tube refrigerator 10 First pulse tube which is a pulse tube 20 Regenerator 30 Compressor 31 Cylinder 32 Piston 33 Second pulse tube which is another pulse tube

Claims (2)

[Claims] 1. A pulse tube refrigerator comprising: a pulse tube; a regenerator connected to a low temperature side of the pulse tube; and a compressor connected to a high temperature side of the regenerator. Is a pulse tube and another regenerator with one end connected in parallel to the regenerator, and a cylinder connected in series between the other end of the other pulse tube and another regenerator. And a mechanically driven piston is provided in the cylinder, and the one end of the another pulse tube is maintained at a lower temperature than the one end of the cylinder. A pulse tube refrigerator. 2. The pulse tube refrigerator according to claim 1, wherein the regenerator and another regenerator constituting the compressor are provided integrally.