WO2004088217A1

WO2004088217A1 - Pulse tube refrigerator

Info

Publication number: WO2004088217A1
Application number: PCT/JP2004/004253
Authority: WO
Inventors: Yoichi Matsubara; Hiroyuki Sugita; Akihiro Kushino
Original assignee: Japan Aerospace Exploration Agency; Nihon University
Priority date: 2003-03-28
Filing date: 2004-03-26
Publication date: 2004-10-14
Also published as: EP1610075A1; CN100371657C; JPWO2004088217A1; CN1768238A; JP4362632B2; US20060277925A1

Abstract

A pulse tube refrigerator that is small in size and free from vibration and electric noise. A pulse tube refrigerator (1) has a pulse tube, a cool storage unit connected to the low- temperature side of the pulse tube, a vibration generator connected to the high-temperature side of the cool storage unit, and a reservoir with an orifice, connected to the high-temperature side of the pulse tube. The vibration generator is a thermally driven pressure wave generator having thermal drive tubes (heat exchangers (4-4a) for heat radiation), a phase shifter (7), and a return path (6). Sufficiently heating a heat exchanger (3) for heating causes self-exciting vibration to be generated in a work transmission tube (5), and work is returned to the thermal drive tubes through the phase shifter (7) and the return path (6) arranged on the work output side of the work transmission tube (5). The work is amplified by the thermal drive tubes, and is then outputted from the work transmission tube (5) and fed to the pulse tube refrigerator (1). A vibration generator for a pulse tube refrigerator that is small in size and free from vibration and noise can be realized.

Description

Description Pulse tube refrigerator Technical field

The present invention relates to a pulse tube refrigerator, and more particularly, to a pulse tube refrigerator provided with a pressure vibration generator that generates pressure vibration by heat. Background art

The pulse tube refrigerator is a 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. Pulse tube refrigerators have no low-temperature moving parts. In a pulse tube refrigerator using a motor-driven compressor, a high-pressure valve and a low-pressure valve provided between the compressor and the regenerator are alternately opened and closed to generate pressure oscillation in the pulse tube. Gifford's basic pulse tube refrigerator utilizes the surface heat-pumping effect. In the orifice type pulse tube refrigerator, a buffer (reservoir tank) is connected to the high temperature side of the pulse tube via an orifice. The cooling action occurs based on the phase difference between the pressure oscillation in the pulse tube and the displacement of the gas column (virtual gas piston formed in the pulse tube) in the pulse tube. In the double inlet type, the flow path between the orifice and the pulse pipe and the flow path between the regenerator and the compressor are connected via a bypass path having another orifice.

For a heat engine such as a Stirling engine, Fig. 9 shows the energy flow pattern in a device that converts thermal energy into gas pressure energy using a regenerator. It shows what the energy flow looks like by changing the boundary conditions at both ends of the regenerator. Of these patterns, (b) and (C) do not require input work at the cold end of the regenerator. On the other hand, a large sweep volume is required on the low temperature side. (C) is a more realistic condition, and (b) is an ideal condition. A conventional orifice type pulse tube refrigerator will be described with reference to FIG. The pulse tube refrigerator has a pulse tube and a regenerator connected to the low-temperature side of the pulse tube. And a buffer tank connected to the high-temperature end of the pulse tube. A compressor is connected to the high temperature side (room temperature side) of the regenerator. A cold station that generates extremely low temperatures is formed between the pulse tube and the regenerator. The regenerator is made by punching a mesh of braided copper wire into a disk shape, and stacking a plurality of such disk-shaped nets in a metal cylinder. If necessary, additional spheres such as lead may be added.

By assuming a 'gas piston' as shown by the dotted line in the pulse tube, its basic operating principle can be easily explained. A gas piston is a gas that is always present in a pulse tube, and it is named after it acts as a solid biston that expands and contracts. Note the energy flow change caused by the gas passing through the orifice due to the pressure oscillation. When the pressure inside the pulse tube is high, the entropy increases because the pressure drops and the fluid flows into the buffer in an equal-enthalpy manner. Even when the pressure inside the pulse tube is low, the entropy also increases because it flows out of the buffer with a pressure drop in an isenthalpic manner.

In other words, the entropy continues to increase as long as the vibration continues, so that continuous work is absorbed (or consumed) in this part. However, the enthalpy flow in the orifice is zero on the cycle average. As a result, a certain amount of work passes through the pulse tube, and gas biston acts like an expander, lowering the temperature of the junction between the pulse tube and the regenerator, and as a refrigerator. Function. Therefore, the mechanism of refrigeration generation is different from that of the basic pulse tube refrigerator, but rather follows that of the GM cycle or Stirling cycle.

Since the orifice type pulse tube refrigerator is not restricted in principle by the critical temperature gradient, it is possible to achieve a low temperature that could not be reached with the basic type pulse tube refrigerator. However, there is a problem with efficiency. Since all expanded work is converted to heat, it cannot be recovered as work and is not suitable for large-capacity refrigeration systems. Compared with the stirrer cycle and GM cycle, the large amount of enthalby flows through the regenerator and the refrigeration efficiency is poor, requiring a large regenerator.

An ideal regenerator is an infinite space with limited heat and infinite heat transfer surface area. A structure that has a thermal conductivity of infinity in the axial direction of the flow and infinity in the radial direction. For example, if the temperature of the gas flowing in from both ends of the regenerator is 300K and 30 それぞれ, respectively, and if the regenerator keeps a constant temperature gradient, the gas flowing in at 300 流出 will flow out at 30Κ and the gas flowing at 30Κ will flow at 300Κ. Leaked at That is, the gas at any position in the flow direction does not oscillate in temperature.

On the other hand, the most popular type of actual regenerator is a thin stainless steel tube with many fine-grained wire meshes laminated in a circle. Of course, far from the ideal state, the gas oscillates with temperature, resulting in enthalpy flow, reducing the actual refrigeration. The enthalpy flow is the value obtained by integrating the product of the low pressure specific heat of the fluid, the temperature, and the flow rate for one cycle, and is indicated by <Η>. The only way to improve the efficiency of a given regenerator, in other words to reduce Η, is to reduce the flow rate. However, a decrease in flow rate also leads to a reduction in work load. The key is how to increase the work per unit flow.

Since the basic pulse tube assumes an ideal regenerator, the enthalpy flowing H> _R in the regenerator is zero. The suffix R of the energy flow is inside the regenerator and P is inside the pulse tube. Figure 10 also shows how the inefficiency of the regenerator contributes to the reduction of the actual amount of refrigeration. First, focusing on the energy flow in the pulse tube, there is no right-sided heat flow Q> p, which is the source of freezing, unlike the basic type pulse tube. If the inner wall of the pulse tube is completely insulated, there is no heat flow, Q> p = 0, and thus W> p = <H> p, but in fact, it is rather slightly leftward Q> P exists.

Nevertheless, the reason for lowering the temperature better than a basic pulse tube is that the work absorbed by the orifice is significantly greater than the direct heat transport through the pulse tube wall. In other words, the surface heat-pumping effect is limited by the compression ratio, but in the case of the orifice type, even at a low compression ratio, the flow rate can be controlled by adjusting the orifice opening to increase the work absorption. That's why. Entropy increases because the enthalpy flow through the orifice is zero, and the work flow decreases. The increased entropy is released as heat in the heat exchanger. In other words, work was converted to heat. On the other hand, the actual amount of refrigeration is, as evident from Fig. 10, the difference between H> P passing through the pulse tube and H> _R passing through the regenerator. The minimum temperature reached in the refrigerator is that if the input is constant, H> p decreases as the temperature decreases, く> κ increases at the same time, and finally the refrigeration amount Q increases Η> This is because ρ—H> R = 0. Therefore, if it is desired to lower the minimum temperature at least, it is important to reduce the flow rate while keeping the work flow passing through the pulse tube constant, and to reduce H> R.

Fig. 11 shows a pressure vibration generator proposed in Japanese Patent Application No. 2002-179141. In this pressure vibration generator, the heat input section is heated to generate self-excited vibration in the work transmission tube. When the resonator is resonated and work is input to the heat exchanger, this work is amplified through the heat exchanger. The work is transmitted to the work transmission tube and output to the output unit. The output work can be larger than the input work. A part of the output work is used as energy for driving the cylinder. By simply heating, the pressure vibration generator can be driven continuously. The pressure vibration generator can be made much smaller.

The “pulse tube refrigerator” disclosed in Japanese Patent Application Laid-Open No. 11-182958 is a pulse tube refrigerator that is reduced in size and size by shortening the length of a resonance tube of a heat driven compressor. A self-excited vibration is generated in the working gas by heating and cooling the working gas sealed in the resonance tube of the heat driven compressor. The pressure amplitude of the working gas from the heat-driven compressor is applied to the pulse tube and regenerator of the refrigerator to cool and liquefy the fluid in the container such as hydrogen. Use a mixed gas of helium gas and another rare gas as the working gas sealed in the resonance tube to shorten the length of the resonance tube. In particular, a mixed gas of He and Xe is used as the mixed gas.

However, conventional pulse tube refrigerators have a problem that when using a compressor driven by a motor, vibration is large and electric noise is generated. Compressors that use a Stirling vitality, for example, have a problem that the size of the resonance tube increases. In the case of using a cavity resonator, there is a problem that vibration is large. Even the heat-driven compressor of the pulse tube refrigerator disclosed in Patent Document 1 cannot solve such a problem. An object of the present invention is to solve the conventional problems described above and to realize a compact pulse tube refrigerator free from vibration and electric noise. Disclosure of the invention

In order to solve the above problems, the present invention provides a pulse tube, a regenerator connected to a low-temperature side of the pulse tube, a vibration generator connected to a high-temperature side of the regenerator, and a high-temperature side of the pulse tube. A vibration generator for a pulse tube refrigerator equipped with a connected orifice-equipped reservoir is provided by a heat drive tube comprising a heat storage unit, a heat exchanger for heating, a heat exchanger for heat dissipation, and a work transfer tube; and a heat drive tube. The heat-driven pressure wave generator is provided with a phase shifter having one end connected to the output end of the heat-driven tube, and a return path connecting the other end of the phase shifter and the input end of the heat-driven tube. With this configuration, a compact pulse tube refrigerator free from vibration and noise can be realized.

In other words, by using a solid displacer for the resonator and phase shifter of the vibration generator and making it a facing type, vibration can be reduced and the size can be reduced. The conventional resonance tube-type heat-driven pressure wave generator would have to be large because it would not resonate if it was small. Attempting to reduce the size made the efficiency extremely low due to friction between the operating gas and the pipe wall, making it impractical. The use of a solid-state displacer resonator or phase shifter makes it possible to realize a compact and efficient heat-driven pressure wave generator. For the same reason, by providing a solid displacer resonator and phase shifter on the side that absorbs work, a compact and efficient pulse tube refrigerator can be realized. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a conceptual diagram of a heat-driven pressure wave generator used for a pulse tube refrigerator in a first embodiment of the present invention,

FIG. 2 is a conceptual diagram of a heat-driven pressure wave generator used for a pulse tube refrigerator according to a second embodiment of the present invention,

FIG. 3 is a conceptual diagram of a heat-driven pressure wave generator used in a pulse tube refrigerator according to a third embodiment of the present invention, FIG. 4 is a conceptual diagram of a heat-driven pressure wave generator used in a pulse tube refrigerator according to a fourth embodiment of the present invention,

FIG. 5 is a conceptual diagram of a resonator used in a pulse tube refrigerator according to a fifth embodiment of the present invention,

FIG. 6 is a conceptual diagram of a phase shifter used in a pulse tube refrigerator according to a sixth embodiment of the present invention,

FIG. 7 is a conceptual diagram of a leaky phase shifter used in a pulse tube refrigerator according to a seventh embodiment of the present invention,

FIG. 8 is a diagram showing an operation experiment result of the heat-driven pressure wave generator used in the pulse tube refrigerator in the third and fourth embodiments of the present invention,

FIG. 9 is a diagram showing an energy flow pattern in a heat-driven pressure wave generator, FIG. 10 is a diagram showing an energy flow pattern in a conventional pulse tube refrigerator,

FIG. 11 is a conceptual diagram of a heat-driven pressure wave generator used in a conventional pulse tube refrigerator. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 to 8.

(First Embodiment)

A first embodiment of the present invention is a pulse tube refrigerator driven by a heat driven pressure wave generator including a heat driven tube, a phase shifter, and a return path.

FIG. 1 is a conceptual diagram showing a configuration of a pulse tube refrigerator according to a first embodiment of the present invention. In FIG. 1, a pulse tube refrigerator 1 is an orifice type pulse tube refrigerator. This pulse tube refrigerator has a pulse tube, a regenerator connected to the low temperature side of the pulse tube, a vibration generator connected to the high temperature side of the regenerator, and an orifice connected to the high temperature side of the pulse tube. And a reservoir. Although illustration is omitted, it is the same as that shown in FIG. The regenerator 2 is a means for forming an isothermal space having a constant temperature gradient. It is also called a regenerator. Addition The heat exchanger for heat 3 is a means for supplying heat to the high-temperature side of the regenerator 2. The heat exchanger 4 for heat radiation is a means for cooling the low temperature side of the heat storage unit 2 to about room temperature. The work transmission pipe 5 is an adiabatic space, and is a pipe that transmits work by the pressure wave of the working gas. The return path 6 is a tube that returns work from the phase shifter 7 to the regenerator 2. The phase shifter 7 is means for delaying the phase shift of the pressure wave of the working gas by a piston that freely reciprocates in the cylinder. The heat-exchanging heat exchanger 4a is a means for cooling the work output side of the work transfer pipe 5 to about room temperature. The heat exchanger 4 for heat dissipation, the heat storage unit 2, the heat exchanger 3 for heating, the work transfer tube 5, and the heat exchanger 4 for heat dissipation constitute a heat driven tube. The heat drive tube is a device that heats the high-temperature part of the regenerator 2 and cools the low-temperature part to form a constant temperature gradient in the regenerator 2 and amplify the work due to the pressure wave of the working gas. is there. The heat driven tube, the return path 6 and the phase shifter 7 constitute a heat driven pressure wave generator.

The operation of the pulse tube refrigerator according to the first embodiment of the present invention configured as described above will be described. When the phase shifter 7 (displacer) installed symmetrically vibrates symmetrically, the working gas vibrates. As a result, a heat flow is generated from the heating heat exchanger 3 heated to the temperature Th to the heat dissipation heat exchanger 4 cooled to the temperature Ta. As a result, pressure oscillations occur in the system. There is a specific phase difference between this pressure oscillation and the displacement of the working gas, which becomes the work flow. The energy of this work flow is due to the conversion of a part of the heat energy taken into the system to the work energy. Evidence suggests that heat energy emitted from the system is less than heat energy captured.

The work flow goes from the heat-dissipating heat exchanger 4 at the temperature Ta to the heating heat exchanger 3 at the temperature Th. In other words, it is characterized by flowing in the opposite direction to the heat flow. The work flow is amplified in the process of passing through the regenerator 2. A part of the amplified work flow is supplied from the return path 6 to the heat exchanger 4 for radiating the temperature Ta via the phase shifter 7 (displacer). The remaining work is supplied as a drive source for the pulse tube refrigerator 1. Initially, the vibration of the phase shifter 7 (displacer) was assumed, but if the temperature difference between the heating temperature Th and the heat radiation temperature Ta is sufficiently large, it is necessary to drive the phase shifter 7 (displacer) continuously. Even if work is consumed, work to be supplied to the pulse tube refrigerator 1 is left, so self-excited vibration is obtained, and work required for driving is supplied from outside Need not be. .

When part of the work output from the work transfer pipe 5 is returned to the phase shifter 7 (displacer), the piston in the cylinder vibrates. The returned work is converted into a pressure wave having a phase different from that of the input pressure wave in the phase shifter 7 (displacer), and is returned to the low temperature side of the regenerator 2. The returned work is amplified by the regenerator 2, transmitted to the work transfer pipe 5, and output as a traveling wave. The heat driven tube functions as an amplifier that amplifies and outputs the input work. A part of the output work is returned to the phase shifter 7 (displacer) again, and the heat driven tube continuously generates a pressure wave. This heat-driven pressure wave generator can be applied to an inertance type pulse tube refrigerator, and can also be used as a generator.

As described above, in the first embodiment of the present invention, the pulse tube refrigerator is driven by the heat driven pressure wave generator including the heat driven tube, the phase shifter, and the return path. A compact pulse tube refrigerator free from vibration and electrical noise can be realized, and cooling efficiency can be increased with a simple configuration.

(Second embodiment)

The second embodiment of the present invention is a pulse tube refrigerator driven by a heat driven pressure wave generator including a heat driven tube, a resonator, a phase shifter, and a return path. The heat-driven pressure wave generator is a Stirling engine type.

FIG. 2 is a conceptual diagram showing a configuration of a pulse tube refrigerator according to a second embodiment of the present invention. In FIG. 2, a resonator 8 is a gas spring resonator provided on the work output side of the heat driven tube. Other configurations are the same as those of the first embodiment. The basic configuration of this pulse tube refrigerator is the same as the conventional pulse tube refrigerator shown in FIG. The difference is that the piston of the phase shifter can reciprocate freely. The heat-driven pressure wave generator is composed of the heat-driven tube, the return path 6, the phase shifter 7, and the resonator 8.

The operation of the pulse tube refrigerator according to the second embodiment of the present invention configured as described above will be described. When the heating heat exchanger 3 is sufficiently heated, self-excited vibration occurs in the work transfer tube 5, and the resonator 8 resonates with a predetermined phase difference with respect to the self-excited vibration. The pressure wave of the working gas resonates in the resonator 8 provided on the output side of the heat drive tube, and a standing wave is generated. Since the pressure wave generated by the resonance in the resonator 8 is a standing wave, it cannot be taken out as work. The exchange of work with the resonator 8 is zero in one cycle. The amplitude of the working gas moving in the heat driven tube increases, and the work amplified by the heat driven tube is sent to the pulse tube refrigerator 1. The work generated in the regenerator 2 flows in the opposite direction to the heat flow. The operation of the phase shifter 7 is the same as in the first embodiment.

This heat-driven pressure wave generator is a gas-driven self-excited Stirling engine. The state of the energy flow of the Stirling cycle engine is as shown in Fig. 9 (a). The heat Q in is supplied from the high temperature side of the regenerator 2 and is removed from the low temperature side of the regenerator 2 as heat Q out. The phase shifter 7 is used as the acoustic inertia of the return path. The phase shifter 7 and the resonator 8 are symmetrically arranged to reduce mechanical vibration. A flexible bearing is used to support the piston in a floating state. The diameter of the piston is 52 mm. The movable mass is 1.85kg. The size of the regenerator 2 is 52 mm in diameter. It is 57mm long and is filled with a 200 mesh screen. The clearance between the piston and cylinder is about 15 μιη. The heating temperature is 580580, the average pressure is 1.5Mpa, the driving frequency is 24.5Hz, and the minimum work amplification factor is 1.57. The driving frequency is higher than the resonance frequency of the piston, 23.5 Hz. This heat-driven pressure wave generator can be applied to an inertance type pulse tube refrigerator, and can also be used for a generator.

As described above, in the second embodiment of the present invention, the pulse tube refrigerator is driven by the heat driven pressure wave generator including the heat driven tube, the resonator, the phase shifter, and the return path. As a result, a compact pulse tube refrigerator free from vibration and electrical noise can be realized, and the cooling efficiency can be increased with a simple configuration.

(Third embodiment)

The third embodiment of the present invention is a pulse tube refrigerator driven by a heat driven pressure wave generator including a heat driven tube and a resonator. The heat-driven pressure wave generator is a standing wave type. FIG. 3 is a conceptual diagram showing a configuration of a pulse tube refrigerator according to a third embodiment of the present invention. In FIG. 3, a regenerator 2 is a means for forming an isothermal space having a constant temperature gradient. The heat exchanger for heating 3 is a means for supplying heat to the high-temperature side of the regenerator 2. The heat radiation heat exchanger 4 is means for cooling the low temperature side of the heat storage unit 2 to about room temperature. The high temperature buffer 16 is a tube that reflects a pressure wave and generates a standing wave in the heat driven tube. The heat storage tube 2, the heat exchanger 3 for heating, the heat exchanger 4 for heat radiation, and the high-temperature buffer 16 constitute a heat driven tube. The resonator 8 is a gas spring resonator provided at a connection between the heat driven tube and the pulse tube refrigerator 1. The thermally driven tube and the resonator 8 constitute a thermally driven pressure wave generator.

The operation of the pulse tube refrigerator according to the third embodiment of the present invention configured as described above will be described. The pressure wave of the working gas resonates in the resonator 8, and a standing wave is generated.

The closed end of the high-temperature puffer 16 is the node of the standing wave gas displacement. The connection of the resonator 8 is the antinode of the standing wave. The amplitude of the working gas moving in the heat driven tube increases, and the work amplified by the heat driven tube is sent to the pulse tube refrigerator 1. The exchange of work with the resonator 8 is zero in one cycle. This heat-driven pressure wave generator is a standing wave thermoacoustic engine. A rough net regenerator 2 called a stack is used. In this heat driven tube, unlike the first and second embodiments, the direction of work flow is the same as the direction of heat flow. As shown in Fig. 9 (d), energy flows. The work by the pressure wave enters from the cold side of the heat driven tube, is reflected by the high temperature buffer 16, is amplified by the regenerator 2, and exits from the cold side of the heat driven tube. Therefore, the low temperature side of the heat driven tube is the work input / output end. The resonator 8 increases the amplitude of the antinode of the standing wave even when the length of the thermally driven tube is short, so that the pressure wave can be generated efficiently even in a small size. This heat-driven pressure wave generator can be applied to an inertance-type pulse tube refrigerator, and can also be used as a generator.

As described above, in the third embodiment of the present invention, the pulse tube refrigerator is driven by the heat-driven pressure wave generator including the heat-driven tube and the resonator. A pulse tube refrigerator without electric noise can be realized, and the cooling efficiency can be increased with a simple configuration. (Fourth embodiment)

The fourth embodiment of the present invention is a pulse tube refrigerator driven by a heat driven pressure wave generator having a resonator on the side opposite to the output side of the heat driven tube.

FIG. 4 is a conceptual diagram showing a configuration of a pulse tube refrigerator according to a fourth embodiment of the present invention. In FIG. 4, a pulse tube refrigerator 1 is an orifice type pulse tube refrigerator. The heat storage unit 2 is a means for forming an isothermal space having a constant temperature gradient. The heating heat exchanger 3 is a means for supplying heat to the high-temperature side of the regenerator 2. The heat-dissipating heat exchanger 4 is means for cooling the low-temperature side of the heat storage unit 2 to about room temperature. The work transmission pipe 5 is an adiabatic space, and is a pipe that transmits work by a pressure wave of the working gas. The heat-exchanging heat exchanger 4a is means for cooling the work output side of the work transfer pipe 5 to about room temperature. The heat-dissipating heat exchanger 4, the heat storage unit 2, the heating heat exchanger 3, the work transfer tube 5, and the heat-dissipating heat exchanger 4 constitute a heat driven tube. The heat drive tube is a device that heats a high-temperature portion of the heat storage device 2 and cools the low-temperature portion, thereby forming a constant temperature gradient in the heat storage device 2 and amplifying work due to the pressure wave of the working gas. Resonator 8 is a gas spring resonator provided on the opposite side of the connection between the heat driven tube and pulse tube refrigerator 1. The heat driven tube and the resonator 8 constitute a heat driven pressure wave generator. The operation of the pulse tube refrigerator according to the fourth embodiment of the present invention configured as described above will be described. A pair of left and right opposed resonators 8 (displacers) is mounted on the heat exchanger 4 for heat radiation at the temperature Ta. Part of the heat flow from the heating heat exchanger 3 at the temperature Th is converted to a work flow. Further, a part thereof is taken out from the heat-radiating heat exchanger 4 side at the temperature Ta and used to drive the resonator 8 (displacer). The remaining work is taken out from the heating heat exchanger 3 at the temperature Th and supplied to the pulse tube refrigerator 1 via the work transfer pipe 5. Since no loop is formed, there is no need to worry about instability due to circulation.

The pressure wave of the working gas resonates by the resonator 8, and a standing wave is generated in the resonator 8. The amplitude of the working gas moving in the heat driven tube increases, and the work amplified by the heat driven tube is sent to the pulse tube refrigerator 1. The exchange of work with the resonator 8 is 0 in one cycle. In the experiment of the heat-driven pressure wave generator, oscillation was performed at a resonance frequency of 31.5 Hz using the working gas as the healing gas. With an average pressure of 2.3 Mpa suitable for driving a pulse tube refrigerator, a pressure ratio of 1.1 or more was obtained. The heating temperature Th is 723 K and the cooling temperature Ta is 290 K. Once the pressure oscillation started, the oscillation continued until the heating temperature fell below 450 K. The experimental results are shown in FIG. This heat-driven pressure wave generator can be applied to an inertance type pulse tube refrigerator, and can also be used for a generator.

As described above, in the fourth embodiment of the present invention, the pulse tube refrigerator is driven by the heat driven pressure wave generator including the resonator on the side opposite to the output side of the heat driven tube. Therefore, a compact pulse tube refrigerator free from vibration and electric noise can be realized, and the cooling efficiency can be increased with a simple configuration.

(Fifth embodiment)

The fifth embodiment of the present invention is a pulse tube refrigerator including a gas spring resonator between a pulse tube and an orifice.

FIG. 5 is a conceptual diagram showing a configuration of a pulse tube refrigerator according to a fifth embodiment of the present invention. In FIG. 5, a resonator 8a is a resonator in which biston reciprocates using a closed gas as a spring. The reservoir 13 is a buffer tank for storing the working gas. The orifice 14 is a passage through which the working gas passes with resistance. Other configurations are the same as those of the fourth embodiment.

The operation of the pulse tube refrigerator according to the fifth embodiment of the present invention configured as described above will be described. In general, as an efficient phase control mechanism of a pulse tube refrigerator, an “inertance phase control mechanism” in which a long tube called an inertance tube and a reservoir container are connected in series is used. However, this mechanism cannot be efficiently applied to small pulse tube refrigerators. The reason is that it is necessary to reduce the diameter of a long tube, and as a result, the pressure loss of the gas oscillating inside the tube increases, and at the same time, the mass of the gas existing there decreases, so that the ideal resonance This is because the condition no longer holds.

If you use a control system that uses both a solid piston and an orifice, Even if the size is reduced, the ideal resonance condition is satisfied. The ideal resonance condition means that the phase difference between the gas displacement and the pressure oscillation at the hot end of the pulse tube exceeds 90 degrees. With the recent advances in micromechanical technology, the production of ultra-small bistons is not difficult, which is another factor that makes this technology closer to realization. This type of phase control mechanism is important for miniaturizing the pulse tube refrigerator.

Due to the resonator 8a provided between the pulse tube 15 and the orifice 14, even a short pulse tube can resonate. Since the resonator 8a is the antinode of the vibration, the working gas can be exchanged with the orifice 14 with a large amplitude. A compact and efficient phase control mechanism can be created. The pressure vibration generator can be of any type.

As described above, in the fifth embodiment of the present invention, the pulse tube refrigerator is provided with the gas spring resonator between the pulse tube and the orifice, so that a long resonance tube is not used. A compact pulse tube refrigerator free from vibration and electrical noise can be realized, and the cooling efficiency can be increased with a simple configuration.

(Sixth embodiment)

A sixth embodiment of the present invention is a pulse tube refrigerator including a phase shifter between a pulse tube and an orifice.

FIG. 6 is a conceptual diagram showing a configuration of a pulse tube refrigerator according to a sixth embodiment of the present invention. In FIG. 6, a phase shifter 7 is means for delaying the moving phase of the working gas. Other configurations are the same as those of the fourth embodiment.

The operation of the pulse tube refrigerator according to the sixth embodiment of the present invention configured as described above will be described. The phase shifter 7 provided between the pulse tube 15 and the orifice 14 delays the moving phase of the working gas, thereby increasing the cooling efficiency. Compared with the case where only the orifice 14 is used, the phase shifter 7 can increase the amount of phase shift of the gas displacement with respect to the pressure wave, thereby increasing the cooling efficiency. Assuming that the phase without the orifice 14 is 0 degrees, the phase difference becomes 90 degrees when the orifice 14 is provided. Further, when the phase shifter 7 is provided, the phase difference becomes about 110 degrees. In addition, since the characteristics of the phase shifter 7 can be designed according to the purpose, optimal operation characteristics can be realized. Any type of pressure vibration generator for driving the pulse tube refrigerator can be used.

As described above, in the sixth embodiment of the present invention, the pulse tube refrigerator is provided with the phase shifter between the pulse tube and the orifice. It is possible to realize a pulse tube refrigerator that does not have a simple configuration and increase the cooling efficiency with a simple configuration.

(Seventh embodiment)

A seventh embodiment of the present invention is a pulse tube refrigerator including a leakage phase shifter between a pulse tube and a reservoir.

FIG. 7 is a conceptual diagram showing a configuration of a pulse tube refrigerator according to a seventh embodiment of the present invention. In FIG. 7, the leak phase shifter 12 is a displacer having a gap through which a working gas passes between the cylinder and the piston. There are no orifices.

The operation of the pulse tube refrigerator according to the seventh embodiment of the present invention configured as described above will be described. The leaky phase shifter 12 provided between the pulse tube 15 and the reservoir 13 has a function of both a displacer and an orifice. Functionally, it is almost the same as the sixth embodiment. In the sixth embodiment, the phase shifter and the orifice are connected in series, whereas in this example, the phase shifter and the orifice are functionally connected in parallel. By using the gap between the cylinder and the piston of the leak phase shifter 12 as an orifice, it is not necessary to separately provide an orifice, and the device can be downsized. The pressure vibration generator may be of any type.

As described above, in the seventh embodiment of the present invention, the pulse tube refrigerator has the configuration in which the leakage phase shifter is provided between the pulse tube and the reservoir. realizable. Industrial applicability

As is apparent from the above description, the present invention provides a pulse tube, a regenerator connected to the low-temperature side of the pulse tube, a vibration generator connected to the high-temperature side of the regenerator, and a pulse generator. The vibration generator of the pulse tube refrigerator equipped with a reservoir with an orifice connected to the high-temperature side of the heat pipe is a heat-driven pipe consisting of a heat storage unit, a heat exchanger for heating, a heat exchanger for heat dissipation, and a work transfer tube. A phase shifter having one end connected to the output end of the heat driven tube, and a feedback path connecting the other end of the phase shifter and the input end of the heat driven tube. Therefore, a compact pulse tube refrigerator free from vibration and noise can be realized.

Claims

The scope of the claims

1. A pulse tube, a regenerator connected to a low temperature side of the pulse tube, a vibration generator connected to a high temperature side of the regenerator, and a reservoir with an orifice connected to a high temperature side of the pulse tube. A pulse tube refrigerator comprising: a heat drive tube including a heat storage unit, a heat exchanger for heating, a heat exchanger for heat dissipation, and a work transfer tube; and an output end of the heat drive tube. A pulse tube refrigeration device comprising: a phase shifter having one end connected to the heat transfer pressure generator; and a return path connecting the other end of the phase shifter and an input end of the heat drive tube. Machine.

2. A pulse tube, a regenerator connected to the low-temperature side of the pulse tube, a vibration generator connected to the high-temperature side of the regenerator, and a reservoir with an orifice connected to the high-temperature side of the pulse tube A pulse tube refrigerator comprising: a vibration generator, a heat drive tube including a heat storage device, a heat exchanger for heating, a heat exchanger for heat radiation, and a high-temperature puffer; and a low-temperature portion of the heat drive tube. A pulse tube refrigerator characterized by being a thermally driven pressure wave generator having a resonator connected to an end.

3. A pulse tube, a regenerator connected to a low temperature side of the pulse tube, a vibration generator connected to a high temperature side of the regenerator, and a reservoir with an orifice connected to a high temperature side of the pulse tube. A pulse tube refrigerator comprising: a heat drive tube including a heat storage device, a heat exchanger for heating, a heat exchanger for heat radiation, and a work transfer tube; and an input end of the heat drive tube. A pulse tube refrigerator characterized by being a heat driven pressure wave generator comprising a resonator connected to a pulse tube refrigerator.

4. A pulse tube, a regenerator connected to a low temperature side of the pulse tube, a vibration generator connected to a high temperature side of the regenerator, and a reservoir with an orifice connected to a high temperature side of the pulse tube. A pulse tube refrigerator comprising: a pulse tube refrigerator including a gas spring resonator between the pulse tube and the orifice.

5. A pulse tube, a regenerator connected to a low temperature side of the pulse tube, a vibration generator connected to a high temperature side of the regenerator, and a reservoir with an orifice connected to a high temperature side of the pulse tube. A pulse tube refrigerator comprising: the pulse tube; A pulse tube refrigerator characterized by having a phase shifter between the refill and the orifice.

6. A pulse tube, a regenerator connected to a low temperature side of the pulse tube, a vibration generator connected to a high temperature side of the regenerator, and a reservoir connected to a high temperature side of the pulse tube. A pulse tube refrigerator comprising: a leakage phase shifter between the pulse tube and the reservoir.