JP2003329325A - Cold storage unit mounting structure of pulse tube refrigerating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce vibration of a cooling stage. <P>SOLUTION: Hot ends of a cold storage unit cylinder 34 and pulse tube cylinders 35 and 36 are inserted into and fixed to holes formed in a cylinder flange 8. After a mesh-like cold storage material 10 is filled in the cylinder 34, plugs 38 and 41 provided with holes communicating with a passage 14 are fitted, mounted and fixed to openings of the cylinder 34 and the cylinders 35 and 36 by freeze fitting or screwing. By increasing the rigidity of the cylinder flange 8 like this, deformation of the cylinder flange 8 caused by pulsation of pressure in the cylinders 35 and 36 is restrained and the vibration of the cooling stage 25 is prevented. After the cylinder 34 is fixed to the cylinder flange 8, the storage material 10 is filled in the cylinder 34 to prevent thermal influence on the storage material 10 in freeze fitting. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a regenerator mounting structure of a pulse tube refrigerator.

[0002]

2. Description of the Related Art Conventionally, as a refrigerator, Japanese Patent Laid-Open No. 2001-2001
There is a pulse tube refrigerator as disclosed in Japanese Patent Publication No. 263840. This pulse tube refrigerator has no moving parts like the displacer of the Gifford McMahon type refrigerator in the low temperature part, has a simple structure, and is expected as a refrigerator with less vibration.

The pulse tube refrigerator has a regenerator and a pulse tube. The high temperature end of the regenerator is connected to the discharge port of the compressor by the high pressure side valve, and is connected to the suction port of the compressor by the low pressure side valve. The low temperature end of the regenerator is connected to the low temperature end of the pulse tube, and the high temperature end of the pulse tube is connected to the buffer tank via an orifice.

In the above structure, when the low-pressure side valve is closed while the high-pressure side valve is opened, high-pressure working gas (helium gas or the like) is introduced from the compressor into the regenerator to serve as a regenerator material. Reaching the low temperature end while exchanging heat,
It flows into the cold end of the pulse tube. Then, the working gas already present in the pulse tube is pushed by the newly introduced working gas and moves to the high temperature end side. As a result, the pressure in the pulse tube becomes higher than the pressure in the buffer tank, and the working gas flows into the buffer tank through the orifice.

Next, when the high pressure side valve is closed while the low pressure side valve is opened, the working gas on the high temperature end side of the regenerator is sucked into the compressor, and along with it, the operation in the pulse tube. The gas flows into the low temperature end side of the regenerator, cools the regenerator material, moves to the high temperature end side while increasing the temperature, and returns to the suction port of the compressor. At that time, the working gas in the buffer tank returns to the pulse tube through the orifice.

In this way, the working gas is repeatedly compressed and expanded in the pulse tube, and adiabatic expansion at that time produces cold heat to cool the cooling stage provided at the low temperature end of the regenerator to about 30K to 80K. It When the regenerator is configured in two stages and each regenerator of each stage is connected to a different pulse tube, the cooling stage of the second regenerator is cooled to 10K or less. Further, when a magnetic material having a large specific heat even at an extremely low temperature is used on the low temperature end side of the second-stage regenerator, it is cooled to 4K or less.

As described above, in the above conventional pulse tube refrigerator, there is no movable part in the pulse tube like the above displacer. Therefore, it has little vibration and is used for cooling precision equipment such as optical equipment.

[0008]

However, the above-mentioned conventional pulse tube refrigerator has the following problems.

FIG. 4 shows an example of a mounting structure of a regenerator and a pulse tube in a conventional pulse tube refrigerator having the above-mentioned structure. The high temperature end of the regenerator cylinder 101 forming the regenerator and the high temperature end of the pulse tube cylinder 102 forming the pulse tube are connected to the cylinder flange 10.
3 are inserted into holes 104 and 105 having inner diameters substantially the same as the outer diameters of both cylinders 101 and 102,
It is fixed by welding or the like.

Then, in the pulse tube cylinder 102, the pressure pulsates between a low pressure and a high pressure due to the working gas flowing in and out. Therefore, the pulse tube cylinder 1
Cylinder flange 103 in synchronization with the pressure fluctuation in 02.
Is deformed, which causes a problem that a cooling stage (not shown) provided at the low temperature end of the pulse tube cylinder 102 vibrates. In addition, as described above, when the regenerator is configured in two stages and each stage regenerator is connected to a different pulse tube cylinder, the cylinder flange 103 is provided with three pulse tube cylinders including three. The above cylinders are connected and fixed, and the cylinder flange 103
Since the rigidity of the cylinder is further reduced, the cylinder flange 10
The deformation of 3 becomes larger.

Although the vibration of the cooling stage as described above is smaller than the vibration caused by the movement of the displacer, it is still smaller than that. It is possible to further improve the measurement accuracy of the device.

Therefore, an object of the present invention is to provide a regenerator mounting structure for a pulse tube refrigerator in which deformation of the cylinder flange can be suppressed and vibration of the cooling stage can be further reduced.

[0013]

In order to achieve the above object, the invention according to claim 1 is directed to a regenerator which is switched and connected to a high pressure gas chamber and a low pressure gas chamber by a switching valve, and a tip portion of the regenerator. A regenerator mounting structure for a pulse tube refrigerator having a pulse tube communicating with the pulse tube and a cooling stage provided at the tip of the pulse tube, which is attached to the main body and the base ends of the regenerator and the pulse tube. And a plug having a hole that fills at least the inner side of the base end of the regenerator and has a hole, and is integrally mounted and fixed to the cylinder flange via the base end of the regenerator. It is characterized by having.

According to the above construction, at least the base end of the regenerator is provided with the plug having the hole filled therein and having the hole, and is integrally fixed to the cylinder flange through the base end of the regenerator. ing. Therefore, the rigidity of the cylinder flange becomes greater than that without the plug, and the periodic deformation of the cylinder flange due to the pulsation of gas pressure in the pulse tube attached to the cylinder flange is reduced. In this way, vibration of the cooling stage provided at the tip of the pulse tube is prevented.

Further, after the regenerator is fixedly attached to the cylinder flange, the base end of the regenerator is closed by the plug. Therefore, it becomes possible to fill the regenerator material with the regenerator after attaching and fixing the regenerator to the cylinder flange, and the thermal effect on the regenerator when attaching and fixing the regenerator to the cylinder flange. Disappears.

According to a second aspect of the present invention, in the regenerator mounting structure of the pulse tube refrigerator according to the first aspect of the invention, the inside of the base end portion of the pulse tube is filled and has a hole, It is characterized in that it has a plug integrally attached and fixed to the cylinder flange via the base end portion of the pulse tube.

According to the above construction, the base end of the pulse tube is provided with a plug that fills the inside and has a hole, and is integrally fixed to the cylinder flange through the base end of the pulse tube. ing. Therefore, the rigidity of the cylinder flange becomes larger than that of the invention according to claim 1, and the periodic deformation of the cylinder flange is further reduced.

According to a third aspect of the present invention, in the regenerator mounting structure of the pulse tube refrigerator according to the first aspect of the invention, the base end of the pulse tube is attached to the mounting surface of the pulse tube on the cylinder flange. Is provided in the groove surrounded by the groove, and the pulse tube has a hole formed in the region. It is characterized by being attached and fixed to the flange.

According to the above construction, the base end portion of the pulse tube is fitted and fixed in the groove provided in the cylinder flange. Therefore, the cylinder flange is not formed with a hole into which the proximal end portion of the pulse tube is inserted, and the rigidity of the cylinder flange becomes larger than that of the inventions according to claim 1 and claim 2. The cyclic deformation of the cylinder flange is further prevented.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a sectional view of a pulse tube refrigerator to which the cool storage tube mounting structure of the pulse tube refrigerator of the present embodiment is applied.

This pulse tube refrigerator comprises a first regenerator 1 and
The second regenerator 2 is provided in series with the tip of the first regenerator 1 and communicates with the tip of the first regenerator 1.
Has a first pulse tube 3 communicated with the tip of the second regenerator 2 and a second pulse tube 4 having a tip communicated with the tip of the second regenerator 2 by a communication tube 6. Then, the base ends of the first regenerator 1, the first pulse tube 3 and the second pulse tube 4 are connected to the valve chamber 7
It is inserted and fixed in a cylinder flange 8 attached to the end surface of the valve chamber 7, and the valve chamber 7 is fixed in the motor chamber 9. Here, a mesh-shaped regenerator material 10 (only part of which is shown) is stacked and filled in the first regenerator 1, and a spherical regenerator material 11 (only part of which is shown) is filled in the second regenerator 2. It is stacked and filled.

A switching valve 12 composed of a rotor and a stator is provided in the valve chamber 7, and a motor chamber 9 is provided.
By rotating and driving the rotor of the switching valve 12 by the drive motor 13 provided in the, the base end portion of the first regenerator 1 is provided with the high pressure chamber 16 having the introduction port 15 and the discharge port 17 via the passage 14. Is connected to the low pressure chamber 18 having The drive motor 13 is housed in the high pressure chamber 16, the introduction port 15 is connected to the discharge port of the compressor 19, and the discharge port 17 is connected to the suction port of the compressor 19.

Further, the base end portion of the first pulse tube 3 is communicated with the passage 14 by the flow path in which the first flow path resistor 20 is provided. Furthermore, the base end of the first pulse tube 3 is
The flow path resistor 21 is connected to the buffer tank 22 through the flow path. Although not shown in FIG. 1, the base end portion of the second pulse tube 4 is also communicated with the passage 14 and the buffer tank 22 by a flow passage having a flow passage resistance.

In the pulse tube refrigerator having the above structure, the switching valve 12 is rotated by the drive motor 13 to switch and connect the base end portion of the first regenerator 1 to the high pressure chamber 16 and the low pressure chamber 18. Similarly to the conventional pulse tube refrigerator, the working gas is repeatedly compressed and expanded in the first pulse tube 3, and the tip end of the first regenerator 1 is generated by the cold heat generated by the adiabatic expansion at that time. The shield cooling stage 23 provided in the section and the cooling stage 24 provided at the tip of the first pulse tube 3 are cooled to about 30K to 80K.

Furthermore, since the regenerator of this pulse tube refrigerator is constructed in two stages, the high pressure working gas introduced from the high pressure chamber 16 into the first regenerator 1 is the tip of the first regenerator 1. Is introduced into the base end portion of the second regenerator 2. And the second
The heat reaches the tip portion while exchanging heat with the regenerator material 11 of the regenerator 2, passes through the communication tube 6, and flows into the tip portion of the second pulse tube 4. Then, the working gas already present in the second pulse tube 4 is pushed by the newly introduced working gas and starts to move to the base end side. At the same time, the working gas flows into the base end portion of the second pulse tube 4 through the first flow path resistance, and the working gas flowing from the tip end portion of the second pulse tube 4 is suppressed. As a result, the timing of movement of the working gas lags behind the timing of pressure change in the second pulse tube 4. After that, the pressure in the second pulse tube 4 becomes higher than the pressure in the buffer tank 22, and the working gas on the proximal side flows into the buffer tank 22 through the second flow path resistance. The working gas inside moves to the base end side.

Next, when the first regenerator 1 is switched and connected to the low pressure chamber 18, the working gas in the second regenerator 2 is changed to the first regenerator 1 as the pressure in the first regenerator 1 is reduced. Begins to be inhaled. Then, the working gas already present in the second pulse tube 4 is sucked into the second regenerator 2, and the working gas in the second pulse tube 4 starts to move to the low temperature end side. At the same time, the working gas on the proximal end side of the second pulse tube 4 flows out through the first flow path resistance, and the working gas flowing out from the tip end portion of the second pulse tube 4 is suppressed. Then, the working gas in the buffer tank 22 returns to the second pulse tube 4 through the second flow path resistance, and the working gas in the second pulse tube 4 flows into the low temperature end side of the second regenerator 2, The regenerator material 11 is cooled and moves to the high temperature end side while increasing the temperature, and passes through the first regenerator 1 to the compressor 19
Return to the intake port of.

Thus, in the second pulse tube 4, the working gas cooled to about 30K to 80K by the first pulse tube 3 is repeatedly compressed and expanded, and the cold heat generated by the adiabatic expansion at that time causes The cooling stage 25 provided at the tip of the 2-pulse tube 4 is cooled to about 4K.

FIG. 2 shows an example of a structure for mounting the first regenerator 1, the first pulse tube 3 and the second pulse tube 4 on the cylinder flange 8. The high temperature ends of the regenerator cylinder 34 of the first regenerator 1, the pulse tube cylinder 35 of the first pulse tube 3 and the pulse tube cylinder 36 of the second pulse tube 4 are formed in the cylinder flange 8 as shown in FIG. The cylinders 34, 35, 36 are inserted into the holes 31, 32, 33 having an inner diameter substantially the same as the outer diameter of the cylinders 34, 35, 36, and fixed by welding or the like. Then, the mesh-shaped regenerator material 10 is stacked and filled in the regenerator cylinder 34.

After that, the opening of the regenerator cylinder 34 has an outer diameter substantially the same as the inner diameter of the regenerator cylinder 34, and a hole 37 communicating with the passage 14 formed in the valve chamber 7 at the center. The first plug 38 provided with is fitted and fixed by cold fitting or screwing. In addition, the opening of the pulse tube cylinder 35 has an outer diameter substantially the same as the inner diameter of the pulse tube cylinder 35, and a hole communicating with a flow path resistance channel 39 formed in the valve chamber 7 in the center. The second plug 41 provided with 40 is fitted and fixed by cold fitting or screwing. Similarly, although not shown, the pulse tube cylinder 3
A third plug similar to the second plug 41 is fitted in the opening 6 and is fixedly attached by cold fitting, screwing or the like.

In this way, the cylinder flange 8
Three holes 31, 32, 33 for inserting the regenerator cylinder 34 and the pulse tube cylinders 35, 36 formed in the
The regenerator cylinder 34 and the pulse tube cylinder 35,
36 and small holes 37, 40 (only two shown) 3
The first, second, and third plugs 38, 41 (only two of which are shown) are covered and integrated by cold fitting to increase the rigidity of the cylinder flange 8. Therefore, the deformation of the cylinder flange 8 due to the pulsation of pressure in the pulse tube cylinders 35, 36 is suppressed.

As described above, in the present embodiment,
The regenerator cylinder 34 and the pulse tube cylinder 35,
The high temperature end of 36 is inserted into the holes 31, 32, 33 for the cylinders 34, 35, 36 formed in the cylinder flange 8 and fixed by cold fitting. After the mesh-shaped regenerator material 10 is filled in the regenerator cylinder 34, the regenerator cylinder 34 and the pulse tube cylinder 3 are filled.
Plugs 38 and 41 (only two are shown) provided with holes communicating with the passage of the valve chamber 7 are fitted in the openings of 5, 36,
It is attached and fixed by cold fitting or screwing.

Therefore, the rigidity of the cylinder flange 8 can be increased, the deformation of the cylinder flange 8 due to the pulsation of pressure in the regenerator cylinder 34 and the pulse tube cylinders 35, 36 can be suppressed, and the cooling stage 25
The vibration of can be prevented. Further, after the high temperature end of the regenerator cylinder 34 is fixed to the cylinder flange 8, the regenerator material 10 can be filled in the regenerator cylinder 34. Therefore, the cold storage material 1 at the time of cold fitting
The thermal effect on 0 can be eliminated. Further, when the plugs 38 and 41 are fixed by screws, the plug 38 can be removed and the regenerator material 10 can be replaced, and maintenance can be easily performed.

That is, according to the pulse tube refrigerator of the present embodiment, the vibration of the cooling stage 25 can be made smaller than that of the conventional pulse tube refrigerator, and the precision of optical equipment etc. attached to the cooling stage 25 can be improved. The influence of vibration on the equipment can be reduced, and the measurement accuracy of the precision equipment can be greatly improved as compared with the conventional pulse tube refrigerator.

In the above embodiment, all of the regenerator cylinder 34, pulse tube cylinder 35 and pulse tube cylinder 36 are plugged.
This is not always necessary. The plug is closed on the cylinder because it is necessary to insert and fill the regenerator material into the cylinder after fixing the cylinder to the cylinder flange 8. Therefore, the pulse tube cylinders 35 and 36, which originally do not need to be filled with the cold storage material, do not necessarily need to be plugged.

Therefore, the pulse tube cylinders 35 and 36 are
In this case, the rigidity of the cylinder flange 8 can be further increased by making the mounting structure as follows. That is, a circular groove into which the high temperature ends of the pulse tube cylinders 35 and 36 are fitted is formed in the cylinder flange 8 at the position where the pulse tube cylinders 35 and 36 are attached, and a circular groove is formed in the center of the groove. A hole communicating with the flow channel 39 for flow channel resistance is provided. Then, the high temperature ends of the pulse tube cylinders 35 and 36 are fitted into the circular grooves formed in the cylinder flange 8 and fixed by welding. By doing so, it is sufficient to form only one hole for inserting the regenerator cylinder 34 in the cylinder flange 8, and the rigidity of the cylinder flange 8 can be further increased.

[0036]

As is apparent from the above, the regenerator mounting structure of the pulse tube refrigerator of the invention according to claim 1 has at least the base end of the regenerator with the base end fixed to the cylinder flange. Since the plug that fills the inner side and has the hole is provided and integrally fixed to the cylinder flange through the base end portion of the regenerator, the rigidity of the cylinder flange can be increased as compared with the case without the plug. Therefore, it is possible to prevent the deformation of the cylinder flange due to the pulsation of the gas pressure in the pulse tube attached to the cylinder flange, and to prevent the vibration of the cooling stage provided at the tip of the pulse tube. it can.

Further, since the base end of the regenerator is closed by the plug after the regenerator is mounted and fixed on the cylinder flange, the regenerator is mounted and fixed on the cylinder flange and then the regenerator is stored in the regenerator. The material can be filled. Therefore, it is possible to eliminate the thermal influence on the regenerator material when the regenerator is attached and fixed to the cylinder flange.

That is, according to the present invention, it is possible to provide a pulse tube refrigerator that is optimal for cooling precision equipment such as optical equipment.

Further, in the regenerator mounting structure of the pulse tube refrigerator of the invention according to claim 2, the inside of the pulse tube whose base end is fixedly attached to the cylinder flange is filled with a hole and has a hole. A plug having the same is provided, and is integrally fixed to the cylinder flange via the base end portion of the pulse tube. Therefore, the rigidity of the cylinder flange can be made higher than in the case of the invention according to the first aspect, and the deformation of the cooling stage can be further prevented.

Further, in the regenerator mounting structure of the pulse tube refrigerator of the invention according to claim 3, the base end of the pulse tube is
It is fitted and fixed in the groove provided in the cylinder flange. Therefore, it is not necessary to form a hole for inserting the base end portion of the pulse tube in the cylinder flange, and the rigidity of the cylinder flange can be improved by the method of claim 1.
It is possible to prevent the deformation of the cooling stage more by making it larger than the case of the invention according to claim 2.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a pulse tube refrigerator to which a cool storage tube mounting structure of a pulse tube refrigerator of the present invention is applied.

FIG. 2 is a diagram showing an example of a mounting structure of a first regenerator, a first pulse tube and a second pulse tube in FIG. 1 to a cylinder flange.

FIG. 3 is a plan view of a cylinder flange in FIG.

FIG. 4 is a diagram showing an example of a mounting structure of a regenerator and a pulse tube in a conventional pulse tube refrigerator.

[Explanation of symbols]

1 ... the first regenerator, 2 ... second regenerator, 3 ... the first pulse tube, 4 ... second pulse tube, 5, 6 ... Communication pipe, 8 ... Cylinder flange, 10,11 ... Regenerator material, 12 ... switching valve, 13 ... Drive motor, 16 ... High pressure chamber, 18 ... Low pressure chamber, 19 ... Compressor, 20,21 ... Flow resistance, 22 ... buffer tank, 24,25 ... Cooling stage, 31, 32, 33 ... holes, 34 ... Regenerator cylinder, 35, 36 ... Pulse tube cylinder, 38, 41 ... Plug.

Claims (3)

[Claims] 1. A high pressure gas chamber (16) provided by a switching valve (12).
And a low pressure gas chamber (18) are connected to the regenerator (1,
2), a pulse tube (3, 4) whose tip communicates with the regenerator (1, 2), and a cooling stage (24, 25) provided at the tip of the pulse tube (3, 4). A structure for mounting a regenerator of a pulse tube refrigerator having a cylinder flange (8), which is mounted on a main body and to which base ends of the regenerators (1, 2) and the pulse tubes (3, 4) are fixed. ) And at least fills the inner side of the base end of the regenerator (1) and has a hole (37), and is integrated with the cylinder flange (8) through the base end of the regenerator (1). A regenerator mounting structure for a pulse tube refrigerator, comprising a plug (38) fixedly mounted. 2. The regenerator mounting structure for a pulse tube refrigerator according to claim 1, wherein the pulse tube (3, 4) is filled with an inner side at a base end portion and has a hole (40), A regenerator mounting structure for a pulse tube refrigerator, comprising a plug (41) integrally mounted and fixed to the cylinder flange (8) through the base ends of the tubes (3, 4). 3. The regenerator mounting structure for a pulse tube refrigerator according to claim 1, wherein the pulse tube (3,
The mounting surface of (4) is provided with a groove into which the base ends of the pulse tubes (3, 4) are fitted, and a hole is formed in a region surrounded by the groove. , 4) are attached and fixed to the cylinder flange (8) by fitting the base end into the groove of the cylinder flange (8). Construction.