JPH05118684A - Pulse tube refrigerator - Google Patents

Abstract

PURPOSE:To improve the refrigerating capacity of a pulse tube refrigerator by a simple structure. CONSTITUTION:A compressor 10 is connected to a cold heat accumulator 14, a low-temperature end heat exchanger 18, a pulse tube 19 and a phase regulating unit 20 sequentially while gaseous refrigerant is moved reciprocally between the phase regulating unit 20 and the compressor 10 whereby the low-temperature end heat exchanger 18 is cooled to an ultralow temperature. The compressor 10 is constituted of a linear motor 22, a driving piston 12 driven by the linear motor 22 and the like while the phase regulating unit 20 is constituted of a power absorbing cylinder 23, an absorbing piston 24 received in the cylinder 23, a power absorbing spring 25, attached to the back surface of the absorbing piston 24, and the like. The absorbing piston 24 is moved reciprocally on the same axial line with respect to the driving piston 12 while the spring 25 of the absorbing piston 24 is connected to the back surface of the driving piston 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse tube refrigeration system which uses a pulse tube to generate an extremely low temperature in a low temperature end heat exchanger and uses this extremely low temperature for cooling various infrared sensors and high temperature superconducting devices. Regarding the machine.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication No. 1-116767 prior to the present invention
In the conventional pulse tube refrigerator described in Japanese Patent Publication No. 0, as shown in FIG. 2, a compressor 1 is sequentially connected to a radiator 2, a regenerator 3, a low temperature end heat exchanger 4 and a pulse tube 5, By moving the gaseous refrigerant back and forth between the high temperature end 5a of the pulse tube 5 and the compressor 1, heat is radiated at the high temperature end 5a and the low temperature end heat exchanger 4 is cooled by that amount of heat. ing. Further, in the pulse tube refrigerator, the high temperature end portion 5a of the pulse tube 5 is connected to the buffer tank 7 through the orifice valve 6 to adjust the flow rate and the phase difference of the circulating refrigerant, thereby improving the refrigeration efficiency. I am trying to improve my ability.

However, in the conventional pulse tube refrigerator of this kind, it is difficult to adjust the flow rate and the phase difference of the refrigerant mutually to the optimum values independently, and it is difficult to adjust the power at the time of this adjustment. There is a drawback that the refrigerating capacity cannot be sufficiently improved because the energy becomes heat and is discarded and the refrigerating efficiency is reduced accordingly.

Further, as shown in FIG. 3, when the piston 8 is arranged at the high temperature end portion 5a of the pulse tube 5 and is moved, the flow rate and phase difference of the circulating refrigerant are adjusted to appropriate values and the freezing is performed. Although the efficiency and capacity can be adjusted appropriately, there is a drawback in that the mechanism section 9 of the piston is required and the refrigerator becomes larger accordingly.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks and improves the refrigerating capacity of a pulse tube refrigerator with a simple structure.

[0006]

According to the present invention, a compressor is sequentially connected to a regenerator, a low temperature end heat exchanger, a pulse tube and a phase adjusting unit, and a gas state is provided between the phase adjusting unit and the compressor. By moving the refrigerant back and forth, the low temperature end heat exchanger is cooled to an extremely low temperature, the compressor is composed of a linear motor and a driving piston or the like driven by the linear motor, and the phase The adjusting unit is composed of a power absorbing cylinder, an absorbing piston housed in the cylinder, and a power absorbing spring attached to the back surface of the absorbing piston, and the absorbing piston is used as the driving piston. On the other hand, while reciprocating on the same axis, the spring of the absorbing piston is connected to the back surface of the driving piston.

[0007]

According to the present invention, the spring of the phase adjusting unit is set to have an appropriate spring constant, so that the absorbing piston of the phase adjusting unit moves with an optimum phase difference and amplitude with respect to the driving piston. By this large movement of the absorbing piston, it becomes possible to independently adjust the gas flow rate and the phase difference to the optimum values in the phase adjusting section, and the power for phase adjustment by the phase adjusting section. Energy is returned to the compressor via the springs, thus increasing the refrigeration efficiency and capacity of the pulse tube refrigerator. Further, the position adjusting section does not require a dedicated mechanism for exerting a damping force or a load on the absorbing piston, and the structure of the pulse tube refrigerator is correspondingly simplified.

[0008]

Next, an embodiment of the present invention will be described.

Reference numeral 10 is a compressor, which is a cylinder 11
A reciprocating type compression piston 12 is housed inside. A ring-shaped sealing material 1 is provided on the outer circumference of the compression piston 12.
3 is fitted. 14 is a pipe for the compressor 10
The regenerator connected at 5 accommodates the regenerator material 16 made of lead, copper, or the like. Reference numeral 17 is a radiating fin provided at the high temperature side end of the regenerator 14, 18 is a low temperature end heat exchanger communicating with the regenerator 14, and 19 is a pulse made of a stainless steel bent tube communicating with the low temperature end heat exchanger 18. It is a tube. The low temperature end heat exchanger 18 and the pulse tube 19 share a case. The low temperature end heat exchanger 18 cools them by applying the cryogenic heat to various infrared sensors and high temperature superconducting devices. Further, the pulse tube 19 causes a pulse-like pressure change therein, and radiates the compression heat generated in the compression process of the compressor 10 from the high temperature end portion 19a and the like. With respect to the pulse tube 19, the thermoacoustic theory teaches that a large refrigerating capacity can be obtained when the displacement of the fluid is large in amount called a traveling wave component which is a component in phase with the pressure.

Reference numeral 20 denotes a high temperature end portion 19 of the pulse tube 19.
The phase adjusting unit communicating with a adjusts the pressure fluctuation and the displacement state of the gaseous refrigerant in the pulse tube 19 so as to have an appropriate phase difference with respect to the compressor 10. Details of the phase adjusting unit 20 will be described later.

The compressor 10 is provided with a linear motor 21, and the linear motor 21 drives the compression piston 12. Although not particularly shown, the linear motor 21 has a coil head attached to the compression piston 12 and intermittently supplies a current to the coil head to intermittently generate an electromagnetic force between the coil head and the magnet 22. Then, the compression piston 12 is reciprocated in the axial direction of the cylinder 11.

The phase adjusting unit 20 includes a cylinder 23 for absorbing the power of the gaseous refrigerant, an absorbing piston 24 housed in the cylinder 23, and the absorbing piston 24.
It is composed of a spring 25 for absorbing power attached to the back surface of the.

Further, the phase adjuster 20 casings the absorbing piston 25 in common with the driving piston 12 to reciprocate on the same axis, and drives the spring 25 of the absorbing piston 24 to drive the absorbing piston 25. It is connected to the back of the working piston 12.

In the pulse tube refrigerator, when the compressor 10 is compressed during the compression process, the compressed refrigerant radiates the compression heat through the radiation fins 17 and the regenerator 14 and flows into the pulse tube 19, which then flows into the pulse tube 19. The residual refrigerant is compressed to transfer the heat of compression to the high temperature end portion 19a.
The heat is radiated from the above and further flows into the phase adjusting unit 20 to push in the absorbing piston 24, so that the motive energy thereof is released to the absorbing spring 25 and cooled by the amount of the energy released. After that, when the compressor 10 is sucked in the expansion process, the gaseous refrigerant returns from the phase adjusting unit 20 at a high speed to move to the pulse tube 19
Adiabatic expansion is performed therein to further lower the temperature, cool the low temperature end heat exchanger 18 and the regenerator 14, and return to the compressor 10. By repeating such a reciprocating movement cycle, the cryogenic temperature of 100 to 20 K (-173 to 253 ° C.) can be obtained in the low temperature end heat exchanger 18.

In the pulse tube refrigerator, the spring 25 of the phase adjusting unit 20 is set to have an appropriate spring constant so that the spring 25 allows the phase adjusting unit 20 to operate.
The absorbing piston 24 moves with an optimum phase difference and amplitude with respect to the driving piston 12, and the large movement of the absorbing piston 24 causes the phase adjusting portion 2 to move.
At 0, the gas flow rate and the phase difference can be independently adjusted to optimum values, and the power energy is adjusted by the spring 25 when the phase is adjusted by the phase adjusting unit 20.
And is reduced to the compressor 10 via the slag to improve the work efficiency of the kinetic system, and thus the refrigeration efficiency and capacity of the pulse tube refrigerator. Further, the position adjusting unit 20 does not require a dedicated mechanism for exerting a damping force or a load on the absorbing piston 24, and the structure of the pulse tube refrigerator is simplified and the size thereof is reduced.

[0016]

Since the present invention is configured as described above, the spring of the phase adjusting portion has an appropriate spring constant,
The spring allows the absorbing piston of the phase adjusting unit to move with an optimum phase difference and amplitude with respect to the driving piston, and due to the large movement of the absorbing piston, the gas flow rate and the phase difference in the phase adjusting unit are increased. Can be independently adjusted to the optimum value, and the energy released during the phase adjustment by the phase adjusting unit can be reduced to the compressor via the spring, and thus the refrigeration efficiency of the pulse tube refrigerator. In addition, the position adjusting section does not require a dedicated mechanism for applying a damping force or load to the absorbing piston, and the structure of the pulse tube refrigerator can be simplified accordingly. The refrigeration capacity of the pulse tube refrigerator can be improved with a simple structure.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional example.

FIG. 3 is a configuration diagram of another conventional example.

[Explanation of symbols]

 10 Compressor 12 Driving Piston 14 Regenerator 18 Low Temperature End Heat Exchanger 19 Pulse Tube 20 Phase Adjuster 21 Linear Motor 23 Cylinder 24 Absorption Piston 25 Spring

Claims (1)

[Claims] 1. A compressor is sequentially connected to a regenerator, a low temperature end heat exchanger, a pulse tube and a phase adjusting unit, and a gaseous refrigerant is reciprocally moved between the phase adjusting unit and the compressor, The low temperature end heat exchanger is cooled to an extremely low temperature, the compressor is composed of a linear motor and a driving piston driven by the linear motor, and the phase adjusting unit is a cylinder for absorbing power. And an absorption piston housed in the cylinder and a power absorption spring attached to the back surface of the absorption piston, and the absorption piston is reciprocally moved on the same axis with respect to the drive piston. In addition, the pulse tube refrigerator is characterized in that the spring of the absorbing piston is connected to the back surface of the driving piston.