JPH0894197A - Pulse tube refrigerating machine - Google Patents

Abstract

PURPOSE: To restrain the transfer of inflow heat, entering into at least one piece of pulse tube to a cold head connected to the pulse tube, and reduce the refrigerating temperature of the cold head by contacting the second cold head of the main body of second pulse tube refrigerating machine thermally with a first pulse tube of the main body of a first pulse tube refrigerating machine. CONSTITUTION: One part of a first refrigerating machine main body 1 is constituted of a double-tube structure substantially and the inner tube thereof is constituting a first pulse tube 18 while the outer tube thereof constitutes a first cool storage device 16 and a first cold head 17 is connected to a connecting site between the first pulse tube 18 and the first cool storage device 16. On the other hand, the second cool storage device 32 of a second refrigerating machine main body 30 is arranged around the lower part of the first cool storage device 16 while a second cold head 33a is connected to the upper end of a first cool storage device 32. In this case, the second cold head 33a is contacted thermally with the substantially central outer wall of the first cool storage device 16 directly and is contacted thermally with the substantially central outer wall of the first pulse tube 18 indirectly through a heat exchanger 38 arranged in the substantially central part of the first cool storage device 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-cylinder pulse tube refrigerator having two or more refrigeration cycles.

[0002]

2. Description of the Related Art In order to cool a plurality of objects to be cooled, 2
It is desired to use a multi-cylinder refrigerator having a refrigeration cycle of a system or more. Further, in recent years, from the viewpoint of improving reliability, attention has been paid to a pulse tube refrigerator in which a low temperature part has no moving parts.

Therefore, as a pulse tube refrigerator having two refrigeration cycles, one disclosed in Japanese Patent Laid-Open No. 5568/1993 is known. The structure of this product will be described with reference to FIG.

The pulse tube refrigerator 100 shown in FIG. 4 is composed of a first refrigerator body 1 and a second refrigerator body 3 having the same refrigeration temperature. The first refrigerator main body 1 includes a compression cylinder 11 and a compression piston 14 that is reciprocally disposed in the compression cylinder 11 and forms a first compression space 12 and a second compression space 13 between the compression cylinder 11. A first regenerator 16 connected to the first compression space 12 via a flexible pipe 15 having a radiator 15a; a first cold head 17 coupled to a low temperature end of the first regenerator 16; The first pulse tube 18 connected to the cold head 17, the expansion cylinder 19 in a room temperature atmosphere, and the high temperature end of the first pulse tube 18 between the expansion cylinder 19 and the expansion cylinder 19 which are reciprocally movable. And an expansion piston 23 which forms a first expansion space 21 and a second expansion space 22 which are connected to each other via a flexible pipe 20. The compression piston 14 is connected to a crankshaft 25 that is a drive source via a rod 24, and the expansion piston 23 is also connected to the crankshaft 25 via a rod 26. here,
The expansion piston 23 leads the compression piston 14 by a predetermined phase difference (for example, 30 °). Also, the compression piston 14
Between the side of the compression cylinder 11 and the expansion piston 23
Piston rings 27 and 28 are arranged between the side portions of the expansion cylinder 19 and the expansion cylinder 19, respectively.

On the other hand, the second refrigerator main body 3 has a second regenerator 32 connected to the second compression space 13 via a flexible pipe 31 having a radiator 31a, and a low temperature end of the second regenerator 32. The second cold head 33 is connected to the second cold head 33, and the second pulse tube 34 is connected to the second cold head 33 and has a high temperature end connected to the second expansion space 22 via the flexible pipe 35. .

In the above refrigerator 100, one compression cylinder, compression piston or the like also serves as the compression portion of two refrigeration cycles, and one expansion cylinder or expansion piston or the like also serves as the expansion portion (ie, phase adjustment mechanism). As a result, the number of parts can be reduced, which is advantageous in terms of cost.

[0007]

However, in the above refrigerator 100, the first refrigerator main body 1 and the second refrigerator main body 3 are not in thermal contact with each other, so that the first refrigerator main body is not in contact. The first freezing temperature of the first cold head 17 is equal to the freezing temperature of the second cold head 33 of the second refrigerator main body 3, and the temperature is not yet low.

Further, focusing attention on the first refrigerator body 1,
As described above, the expansion cylinder 19 and the expansion piston 2
3 is present at room temperature, and the cryogenic first cold head 17
Since they are connected to each other via the first pulse tube 18, various kinds of heat flow in through the first pulse tube 18.
Here, this inflow heat is due to heat convection (that is, a phenomenon in which cold heat moves from the upper part to the lower part: a phenomenon peculiar to the pulse tube refrigerator), and is accompanied by the compression and expansion of the working fluid in the first pulse tube 18. Inflow heat (a phenomenon peculiar to the pulse tube refrigerator), conduction heat of the working fluid from the room temperature side to the low temperature side, etc. are considered.
These various types of inflow heat enter the first cold head 17 that generates refrigeration, and the refrigeration temperature is unlikely to decrease.

Therefore, the present invention relates to a multi-cylinder pulse tube refrigerator having two or more refrigeration cycles, and a cold head to which heat flowing into at least one of the two or more pulse tubes is connected. It is a technical object of the present invention to provide a pulse tube refrigerator capable of suppressing the transmission of the cold head to further lower the freezing temperature of the cold head and lower than the freezing temperatures of other cold heads. Is.

[0010]

The technical means (hereinafter referred to as the first technical means) taken in the invention of claim 1 in order to solve the above technical problems changes the pressure of the working fluid inside. A first pressure oscillation source, a first regenerator connected to the first pressure oscillation source, a first cold head coupled to the low temperature end of the first regenerator, and a first cold head coupled to the first cold head. A first pulse tube refrigerator main body having a pulse tube and a first phase adjusting mechanism connected to a high temperature end of the first pulse tube and adjusting a phase between a pressure fluctuation of the working fluid and a movement of the working fluid; A second pressure vibration source for changing the pressure of the working fluid, a second regenerator connected to the second pressure vibration source, and a second cold head coupled to the low temperature end of the second regenerator,
A second pulse tube connected to the second cold head, and a second
A pulse tube refrigerator having a second pulse tube refrigerator main body, which is connected to the high temperature end of the pulse tube and has a second phase adjusting mechanism for adjusting the phase between the pressure fluctuation of the working fluid and the movement of the working fluid. , The second cold head was in thermal contact with the first pulse tube.

In order to solve the above technical problems, a second aspect is provided.
The technical means taken in the invention (hereinafter referred to as the second technical means) is a first working space between the first cylinder and the first cylinder, which is reciprocally movable in the first cylinder and the first working space. A first piston forming a second working space, a first regenerator connected to the first working space, a first cold head coupled to the low temperature end of the first regenerator, and a first cold head A first pulse tube, a second cylinder, a third working space connected to the high temperature end of the first pulse tube between the second cylinder and the second cylinder, and a fourth working space. A first pulse tube refrigerator main body having a second piston forming a space; a second regenerator connected to the second working space; a second cold head coupled to the low temperature end of the second regenerator; It is connected to the second cold head and its hot end is in the fourth working space. In the pulse tube refrigerator comprising a second pulse tube refrigerator body having a second pulse tube which is continued, is that obtained by thermal contact with the second cold head to the first pulse tube.

In the first and second technical means, in order to further lower the freezing temperature of the first cold head,
It is preferable that the second cold head is also in thermal contact with the first regenerator.

In the above first and second technical means, in order to prevent the radiant heat from entering the low temperature portion of the first pulse tube refrigerator main body and further reduce the freezing temperature of the first cold head, It is preferable that the first cold head, a radiation shield container covering the vicinity of the low temperature end of the first regenerator and the vicinity of the low temperature end of the pulse tube are provided, and the second cold head is also brought into thermal contact with the radiation shield container.

[0014]

According to the first and second technical means, the second cold head of the second pulse tube refrigerator main body is brought into thermal contact with the first pulse tube of the first pulse tube refrigerator main body. Due to convection, inflow heat accompanying compression and expansion of the working fluid in the first pulse tube, conduction heat of the working fluid from the room temperature side (that is, the phase adjustment mechanism or the second cylinder) to the low temperature side, and the like flowing into the first pulse tube It is possible to suppress heat transfer to the first cold head connected to the first pulse tube as much as possible. As a result, the freezing temperature of the first cold head can be lowered, and the freezing temperature of the first cold head can be made lower than that of the second cold head.

Further, since it becomes possible to make a difference in freezing temperature between the cold heads, it is effective when it is desired to cool the two objects to be cooled to different temperatures.

In the first and second technical means, when the second cold head is brought into thermal contact with the first regenerator as well, the freezing temperature of the first cold head can be further lowered and at the same time, 2 It is possible to further increase the temperature difference from the freezing temperature of the cold head.

Further, a radiation shield container covering the first cold head, the vicinity of the low temperature end of the first regenerator and the vicinity of the low temperature end of the pulse tube is provided, and when the second cold head is brought into thermal contact with the radiation shield container, Since the radiant heat can be prevented from entering the low temperature portion of the pulse tube refrigerator main body, the refrigeration temperature of the first cold head can be further lowered, and the temperature difference from the refrigeration temperature of the second cold head can be further increased. be able to.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

The configuration of the pulse tube refrigerator according to the first embodiment will be described with reference to FIGS. 1 and 2. In FIGS. 1 and 2, the same components as those in the conventional technique (FIG. 4) are designated by the same reference numerals.

The pulse tube refrigerator 10 has two refrigeration cycles, and includes a first refrigerator body (first pulse tube refrigerator body) 1 and a second refrigerator body (second pulse tube refrigerator body). It is composed of 30 and.

The first refrigerator body 1 has the same structure as in the prior art.
The compression cylinder 11 and the first compression space (first working space) 1
2, a compression piston 14, a flexible pipe 15 having a radiator 15a, a first regenerator 16, and a first cold head 1
7, a first pulse tube 18, a flexible pipe 20, an expansion cylinder 19, a first expansion space (third working space) 21, an expansion piston 23, rods 24, 26, a crankshaft 25, It is composed of a motor (not shown) that rotationally drives the crankshaft, and piston rings 27 and 28. Here, the compression cylinder 11 and the compression piston 14 configure the pressure vibration source of claim 1, and the expansion cylinder 19 and the expansion piston 23 configure the phase adjustment mechanism of claim 1. In addition to the piston type shown in the figure, a valve type or the like can be applied to the pressure vibration source, and the phase adjustment mechanism uses an orifice type using an orifice and a buffer tank in addition to the piston type shown in the figure. , Valve type, etc. are also applicable.

On the other hand, the second refrigerator main body 30 includes a second compression space (second working space) 13, a flexible pipe 31 having a radiator 31a, a second regenerator 32, and a second cold head 3.
3a, a second pulse tube 34, a flexible pipe 35, and a second expansion space (fourth working space) 22.

The above-mentioned first and second refrigerator main bodies 1 and 3
A working fluid (for example, helium, argon, nitrogen, hydrogen, air, or a mixed gas thereof) having a predetermined pressure (for example, 15 atm) is enclosed in 0. Also, the first and second regenerator 1
6, 32 are composed of metal mesh, metal sphere, lead, rare earth, and other materials.

In the above-mentioned refrigerator 10, one compression cylinder 11 and one compression piston 14 also serve as the compression parts of the two refrigerator main bodies 1 and 30, and one expansion cylinder 19 and one expansion piston 23 expand the same. Since it also serves as a part, the number of parts can be reduced, which is advantageous in terms of cost.

The main part of the present invention will now be described.

The second cold head 33a of the second refrigerator main body 30 includes the first regenerator 16 and the first cold regenerator 16 of the second refrigerator main body 1.
It is in thermal contact with the pulse tube 18, and it is possible to cool the substantially central portion thereof. Also, the second cold head 33a is
A radiation shield container 36 covering the low temperature part of the first regenerator 16, the first cold head 17 and the low temperature part of the first pulse tube 18.
Is also in thermal contact.

The first regenerator 16, the first cold head 17, the first pulse tube 18, the second regenerator 32, the second cold head 33a, the second pulse tube 34 and the radiation shield container 36 are the vacuum case 37. It is covered by and is kept adiabatic.

Next, the specific construction of the essential parts of the pulse tube refrigerator shown in FIG. 1 will be described with reference to FIG.

As shown in the figure, a part of the first refrigerator main body 1 has a substantially double tube structure, an inner tube of which constitutes a first pulse tube 18 and an outer tube thereof comprises a first regenerator. 16 are configured. A first cold head 17 is connected to a connecting portion of the first pulse tube 18 and the first regenerator 16 at an upper end in the drawing.

On the other hand, the second regenerator 3 of the second refrigerator main body 30.
2 is arranged around the lower part of the first regenerator 16, and the second cold head 33a is coupled to the upper end of the second regenerator 32. A spiral passage 33b is formed in the second cold head 33a and communicates with a second pulse tube 34 wound around the second regenerator 32.

Here, the second cold head 33a is in direct thermal contact with the outer wall at the substantially center of the first regenerator 16, and the heat exchange disposed inside the substantially center of the first regenerator 16 is performed. The outer wall at the substantially center of the first pulse tube 18 is indirectly in thermal contact via the container 38. A radiation shield container 36 is provided above the second cold head 33a so as to cover the central portion of the first regenerator 16 to the low temperature portion and the central portions of the first cold head 17 and the first pulse tube 18 to the low temperature portion. It is fixed by bolts (not shown) and is in thermal contact with the second cold head 33a via the mounting portion.

Pulse tube refrigerator 10 constructed as described above
The operation of will be described.

In the first refrigerator body 1, when the compression piston 14 and the expansion piston 23 move toward the top dead center (that is, in the compression stroke), the pressure of the working fluid in the first refrigerator body 1 rises. However, the working fluid vibrates at the respective positions of the first radiator 15a, the first regenerator 16, the first cold head 17 and the first pulse tube 18 and discharges heat. On the other hand, when the compression piston 14 and the expansion piston 23 move toward the bottom dead center (that is, when they enter the expansion stroke), the pressure of the working fluid decreases, and the working fluid becomes the first radiator 15a, the first regenerator 16, the 1 cold head 17 and first pulse tube 1
It vibrates at each position of 8 and absorbs heat. By such an operation, the working fluid in the first regenerator 16 mainly absorbs heat from the regenerator material existing at that position when it moves from the current position to one side, and moves to the other side to the regenerator material existing at that position. It can be realized to exhale heat.

That is, the working fluid distributed in the first regenerator 16 sucks and discharges heat from the regenerator material while reciprocating at each position, so that the heat is stored in the first regenerator 16. Is pumped up like a bucket of heat.
As a result, the temperature of the first cold head 17 coupled to the low temperature end of the first regenerator 16 is lowered to generate freezing, and the heat is transported to the high temperature side and released to the outside. In this way, by reciprocating the compression piston 14 and the expansion piston 23 with a predetermined phase difference, the phase between the pressure change of the working fluid and the movement of the working fluid can be adjusted, and heat can be efficiently transferred from the low temperature side. It is possible to pump to the high temperature side.

The operation of the second refrigerator main body 30 is substantially the same as the operation of the first refrigerator main body 1 described above, and therefore its explanation is omitted.

Here, since the first pulse tube 18 is usually arranged so as to extend in the vertical direction, there is a possibility that cold heat may move from the upper part of the pulse tube to the lower part of the pulse tube during the above operation.

In other words, a thermal convection phenomenon may occur.
Further, there is a possibility that heat accompanying the compression and expansion of the working fluid in the first pulse tube 18 during the above operation may move to the low temperature portion of the first pulse tube 18. Furthermore, the first expansion space 2 at room temperature
The conduction heat of the working fluid may flow from the first to the first pulse tube 18.

The inflow heat or the generated heat may be transferred from the first pulse tube 18 to the first cold head 17, but in the first embodiment, the second cold head 3 is used.
Since 3a is in thermal contact with the first pulse tube 18, it is possible to prevent the inflow heat or generated heat from being transmitted to the first cold head 17.

Further, the first compression space 1 is also provided in the first regenerator 16.
Although the conduction heat transmitted from 2 is generated, in the first embodiment, since the second cold head 33a is also in thermal contact with the first regenerator 16, the conduction heat is transmitted to the first cold head 17. Can be suppressed.

Next, a pulse tube refrigerator according to the second embodiment will be described with reference to FIG.

As shown in the figure, in the pulse tube refrigerator 10a according to the second embodiment, the first pulse tube 18a is wound around the first regenerator 16, and the straight line portion of the first pulse tube 18a. The second cold head 33a is in direct thermal contact with 18aa, and the radiation shield container is abolished, which is the difference from the first embodiment.

In the second embodiment, the second cold head 3 is used.
Since 3a is brought into direct thermal contact with the first pulse tube 18a, the first pulse tube 18a is connected to the first pulse tube 18a in comparison with the first embodiment.
It is possible to further suppress heat from entering the cold head 17.

[0043]

The inventions of claims 1 and 2 have the following effects.

Since the second cold head of the second pulse tube refrigerator main body is brought into thermal contact with the first pulse tube of the first pulse tube refrigerator main body, it is due to thermal convection, the compression expansion of the working fluid in the first pulse tube. First cold head in which the inflow heat due to the flow of heat, the inflow heat of the working fluid from the room temperature side (that is, the phase adjustment mechanism or the second cylinder) to the low temperature side, and the like into the first pulse tube are connected to the first pulse tube. Can be suppressed as much as possible. As a result, the freezing temperature of the first cold head can be lowered, and the freezing temperature of the first cold head can be made lower than that of the second cold head.

Since it is possible to make a difference in freezing temperature between the cold heads, it is effective when it is desired to cool the two objects to be cooled to different temperatures.

The invention of claim 3 has the following effects.

Since the second cold head is also brought into thermal contact with the first regenerator, the freezing temperature of the first cold head can be further lowered and a temperature difference from the freezing temperature of the second cold head can be further increased. be able to.

The invention of claim 4 has the following effects.

The first cold head, the radiation shield container covering the vicinity of the low temperature end of the first regenerator and the vicinity of the low temperature end of the pulse tube are provided, and when the second cold head is brought into thermal contact with the radiation shield container, the first pulse tube Since the radiant heat can be prevented from entering the low temperature part of the refrigerator body, the refrigeration temperature of the first cold head can be further reduced, and
The temperature difference from the freezing temperature of the second cold head can be further increased.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a pulse tube refrigerator according to a first embodiment.

FIG. 2 is a partial cross-sectional view of the pulse tube refrigerator according to the first embodiment.

FIG. 3 is a partial sectional view of a pulse tube refrigerator according to a second embodiment.

FIG. 4 is an overall configuration diagram of a pulse tube refrigerator according to the related art.

[Explanation of symbols]

 10, 10a Pulse tube refrigerator 11 Compression cylinder (first cylinder) 12 First compression space (first working space) 13 Second compression space (second working space) 14 Compression piston (first piston) 16 First regenerator 17 1st Cold Head 18 1st Pulse Tube 19 Expansion Cylinder (2nd Cylinder) 21 1st Expansion Space (3rd Working Space) 22 2nd Expansion Space (4th Working Space) 23 Expansion Piston (2nd Piston) 32nd 2 Regenerator 33a Second cold head 34 Second pulse tube 36 Radiation shield container

Claims (4)

[Claims] 1. A first for changing the pressure of an internal working fluid
A pressure vibration source, a first regenerator connected to the first pressure vibration source, a first cold head coupled to a low temperature end of the first regenerator, and a first cold head coupled to the first cold head. A first pulse tube refrigerator main body having a pulse tube and a first phase adjusting mechanism which is connected to a high temperature end of the first pulse tube and adjusts a phase between a pressure fluctuation of the working fluid and a movement of the working fluid; A second pressure vibration source for changing the pressure of the working fluid inside, and a second regenerator connected to the second pressure vibration source,
A second cold head connected to the low temperature end of the second regenerator, a second pulse tube connected to the second cold head, and a pressure fluctuation of the working fluid connected to the high temperature end of the second pulse tube. Second to adjust the phase between the movement of the working fluid
A pulse tube refrigerator provided with a second pulse tube refrigerator main body having a phase adjusting mechanism, wherein the second cold head is in thermal contact with the first pulse tube. 2. A first cylinder, a first piston which is reciprocally disposed in the first cylinder and which forms a first working space and a second working space between the first cylinder, and the first piston. A first regenerator connected to one working space, a first cold head coupled to the low temperature end of the first regenerator, a first pulse tube connected to the first cold head, and a second
A second working space that is connected to the high temperature end of the first pulse tube between the cylinder and the second cylinder so as to be reciprocally movable, and forms a third working space and a fourth working space. A first pulse tube refrigerator main body having a piston; a second regenerator connected to the second working space; and a second regenerator
A second cold head coupled to the cold end of the regenerator; and a second pulse tube connected to the second cold head and having a hot end connected to the fourth working space
A pulse tube refrigerator provided with a pulse tube refrigerator main body, wherein the second cold head is in thermal contact with the first pulse tube. 3. The pulse tube refrigerator according to claim 1, wherein the second cold head is also in thermal contact with the first regenerator. 4. The radiation shield container according to claim 1, further comprising a radiation shield container that covers the vicinity of the low temperature end of the first cold accumulator, the vicinity of the low temperature end of the pulse regenerator, and the second cold head. Is also in thermal contact with the radiation shield container, a pulse tube refrigerator.