WO2013151089A1

WO2013151089A1 - Thermoacoustic pump

Info

Publication number: WO2013151089A1
Application number: PCT/JP2013/060192
Authority: WO
Inventors: 阿部　誠; 山本　康; 博文黒澤
Original assignee: いすゞ自動車株式会社
Priority date: 2012-04-03
Filing date: 2013-04-03
Publication date: 2013-10-10
Also published as: JP2013213459A; JP6051565B2

Abstract

In order to obtain a required pressure without using a movable part such as a piston, and with high durability and without increasing the heat source temperature when a thermoacoustic engine is used, this thermoacoustic pump (10) is equipped with: multiple thermoacoustic engines (11) wherein a heating unit (21), a stack (22) and a cooling unit (23) are provided on a resonance tube (20) filled with an operating fluid; a connecting pipe (12) connecting the resonance tubes (20) of the multiple thermoacoustic engines (11) in multiple stages; a suction pipe (13) connected to the resonance tube (20) of the thermoacoustic engine (11) located at the uppermost stage; a suction-use check valve (14) attached to the suction pipe (13); a connection-use check valve (15) attached to the connecting pipe (12); a discharge pipe (16) connected to the resonance tube (20) of the thermoacoustic engine (11) located at the lowermost stage; and a discharge-use check valve (17) attached to the discharge pipe (16). The resonant frequency of the sound waves generated in the resonance tube (20) of the thermoacoustic engine (11) located at a lower stage is set so as to be lower than the resonant frequency of the sound waves generated in the resonance tube (20) of the thermoacoustic engine (11) located at an upper stage.

Description

Thermoacoustic pump

The present invention relates to a thermoacoustic pump that supplies a working fluid using a thermoacoustic engine.

Conventionally, an actuator driven by compressed air has been employed in various applications for vehicles such as trucks, and as such an actuator, for example, an auto clutch or the like is known. An air compressor is used to supply compressed air to the auto clutch or the like. For example, a piston pump is used as such an air compressor (see, for example, Patent Document 1).

Conventional piston pumps generally have moving parts such as pistons and cylinders.

JP 2005-315212 A

In the conventional piston pump, the piston and the cylinder are sealed with a piston seal, but since the seal is a normal contact seal, there is a problem that the durability of the seal is low. In order to increase the durability of the seal, it is necessary to lubricate the seal with oil. However, it is necessary to pay attention to the circulation of the oil and the mixing of oil into the compressed air, and it is necessary to remove the oil with a filter or air dryer. was there.

In recent years, research and development of so-called thermoacoustic engines having no mechanical moving parts has been actively carried out (see, for example, Japanese Patent Application Laid-Open No. 2011-208911), and pressure fluctuations generated inside the thermoacoustic engine are utilized. Thus, a pump having no moving parts such as a piston can be realized. However, the pressure amplitude that can be generated inside the thermoacoustic engine increases in proportion to the temperature difference between the heating unit and the cooling unit, but when the heat source temperature is low, a large pressure amplitude cannot be obtained, and the necessary air pressure (pressure) ) May not be obtained.

Accordingly, an object of the present invention is to provide a pump that has no moving parts such as a piston, has high durability, and can obtain a necessary pressure without increasing the heat source temperature when using a thermoacoustic engine. There is.

In order to achieve the above-described object, a thermoacoustic pump according to the present invention includes a plurality of thermoacoustic engines in which a heating unit, a stack, and a cooling unit are disposed in a resonance tube filled with a working fluid. A connection pipe for connecting the resonance pipes of the thermoacoustic engine in multiple stages, a suction pipe connected to the resonance pipe of the thermoacoustic engine located in the uppermost stage, and attached to the suction pipe and located in the uppermost stage A suction check valve for allowing a flow toward the thermoacoustic engine and blocking a reverse flow; and the thermoacoustic mounted on the connecting pipe and positioned on the lower side from the thermoacoustic engine side A check valve for connection that allows a flow toward the engine side and prevents a flow in the reverse direction, a discharge pipe connected to the resonance pipe of the thermoacoustic engine located at the lowest stage, and attached to the discharge pipe Toward the thermoacoustic engine located at the bottom A discharge check valve that prevents flow and allows reverse flow, and the resonance tube has a resonance frequency of sound waves generated in the resonance tube of the thermoacoustic engine located in the lower stage in the upper stage It is set to be lower than the resonance frequency of the sound wave generated in the resonance tube of the thermoacoustic engine.

By making the pipe length of the resonance tube longer as the thermoacoustic engine on the lower stage side, the resonance tube has the resonance frequency of the sound wave generated in the resonance tube of the thermoacoustic engine located in the lower stage on the upper stage. You may set so that it may become lower than the resonant frequency of the sound wave produced in the said resonance tube of a thermoacoustic engine.

The thermoacoustic pump may further include a tank that is disposed in the discharge pipe downstream of the discharge check valve and stores the working fluid that has passed through the discharge check valve.

The thermoacoustic pump may further include a surge tank disposed in the connection pipe.

According to the present invention, there is provided a pump that has no moving parts such as a piston, has high durability, and can obtain a necessary pressure without increasing a heat source temperature when using a thermoacoustic engine. There is an excellent effect of being able to.

It is a block diagram of the thermoacoustic pump which concerns on one Embodiment of this invention. It is a figure explaining the working principle of the thermoacoustic pump which concerns on one Embodiment of this invention. It is a block diagram of the thermoacoustic pump which concerns on other embodiment of this invention. It is a block diagram of the thermoacoustic pump which concerns on other embodiment of this invention. (A) And (b) is a block diagram of the thermoacoustic pump which concerns on other embodiment of this invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows the structure of a thermoacoustic pump according to an embodiment of the present invention.

As shown in FIG. 1, a thermoacoustic pump 10 according to this embodiment includes a plurality of (in this embodiment, two) thermoacoustic engines 11, a connection pipe 12, a suction pipe 13, and a first check valve ( An intake check valve 14, a second check valve (connection check valve) 15, a discharge pipe 16, a third check valve (discharge check valve) 17, and a tank (air tank) 18. I have.

Each thermoacoustic engine 11 is configured by arranging a heating unit (heater) 21, a stack (regenerator) 22, and a cooling unit (cooler) 23 in a resonance tube 20 filled with a working fluid. . When the working fluid in the resonance tube 20 is locally heated in the heating unit 21 and cooled in the cooling unit 23, part of the thermal energy is converted into acoustic energy, which is mechanical energy, and the working fluid in the resonance tube 20 is converted. A self-excited vibration is generated, and an acoustic vibration, that is, a sound wave is generated in the resonance tube 20.

The resonance tube 20 includes a loop tube portion 24 formed in a loop shape (rectangular loop) and a straight tube portion 25 formed in a straight line shape and connected to the loop tube portion 24. In the present embodiment, the heating unit 21, the stack 22, and the cooling unit 23 are disposed in the loop pipe unit 24. As the working fluid, it is preferable to use a gas (compressible fluid) such as air, helium, nitrogen, or argon.

In the thermoacoustic pump 10 according to the present embodiment, the resonance tube 20 is provided in the resonance tube 20 of the thermoacoustic engine 11 in which the resonance frequency of sound waves generated in the resonance tube 20 of the thermoacoustic engine 11 located in the lower stage is located in the upper stage. It is set to be lower than the resonance frequency of the generated sound wave. The resonance tube 20 can set the resonance frequency of the sound wave generated in the resonance tube 20 by appropriately changing the tube length of the resonance tube 20 and the tube thickness of the resonance tube 20. In the present embodiment, the resonance tube 20 resonates sound waves generated in the resonance tube 20 of the thermoacoustic engine 11 located at the lower stage by increasing the length of the straight pipe section 25 as the lower thermoacoustic engine 11. The frequency is set to be lower than the resonance frequency of the sound wave generated in the resonance tube 20 of the thermoacoustic engine 11 located in the upper stage.

Here, the heat exchange performed inside the stack 22 is determined by ωτ defined by the product of the angular velocity ω (omega) of the working fluid and the thermal relaxation time τ (tau) of the working fluid. Further, the angular velocity ω of the working fluid is obtained by ω = 2πf. Here, f is the frequency of the working fluid (resonant frequency of sound waves). Furthermore, the thermal relaxation time τ of the working fluid represents a time until the temperature of the flow path wall (a skeleton material of the metal mesh material 27 described later) and the temperature of the working fluid in the flow path become equilibrium, and τ = It is obtained by r ² / (2α). However, r is a flow path diameter (refer to AA cross section in FIG. 1), and α is a thermal diffusion coefficient of the working fluid. The resonance frequency is preferably set so that ωτ in the stack 22 of the thermoacoustic engine 11 located in the upper stage is equal to ωτ in the stack 22 of the thermoacoustic engine 11 located in the lower stage.

The heating unit 21 performs heat exchange with a high-temperature heat source. The heating unit 21 has a plurality of internal fins 26 arranged in the heating unit 21 so as to be parallel to the flow path (longitudinal direction of the loop tube portion 24). In addition, it is preferable to use waste heat (vehicle waste heat, factory waste heat, etc.) generated in other systems as the high-temperature heat source.

The stack 22 maintains a temperature gradient between the heating unit 21 and the cooling unit 23. The stack 22 includes a metal mesh material (for example, a wire mesh) 27 that is stacked in plural in the stack 22 so as to cross the flow path (longitudinal direction of the loop tube portion 24).

The cooling unit 23 performs heat exchange with a low-temperature heat source. The cooling unit 23 has a plurality of internal fins 28 arranged in the cooling unit 23 so as to be parallel to the flow path (longitudinal direction of the loop tube portion 24).

The connection tube 12 is for connecting the resonance tubes 20 (in the present embodiment, the straight tube portion 25) of the plurality of thermoacoustic engines 11 in multiple stages. The connecting pipe 12 is a thin pipe having a sufficiently smaller diameter than the loop pipe section 24 and the straight pipe section 25. The connecting pipe 12 is preferably connected to each thermoacoustic engine 11 at a location where the pressure fluctuation in the resonance pipe 20 is greatest. Further, the connecting pipe 12 is preferably connected to each thermoacoustic engine 11 at a location away from the engine portion (the heating unit 21, the stack 22, the cooling unit 23) of the thermoacoustic engine 11.

The suction pipe 13 is connected to the resonance pipe 20 (in the present embodiment, the straight pipe section 25) of the thermoacoustic engine 11 located at the uppermost stage, and the working fluid is inside the resonance pipe 20 of the thermoacoustic engine 11 located at the uppermost stage. For inhalation. The suction pipe 13 is composed of a thin pipe having a diameter sufficiently smaller than that of the loop pipe section 24 and the straight pipe section 25. The downstream end of the suction pipe 13 is preferably connected to a location where the pressure fluctuation in the resonance pipe 20 is the largest with respect to the thermoacoustic engine 11 located at the uppermost stage. In addition, the downstream end of the suction pipe 13 is connected to a location away from the engine portion (the heating unit 21, the stack 22, the cooling unit 23) of the thermoacoustic engine 11 with respect to the thermoacoustic engine 11 located at the uppermost stage. Is preferred. In the present embodiment, the upstream end of the suction pipe 13 is open to the atmosphere.

The first check valve 14 is attached to the suction pipe 13 so that the working fluid flows toward the resonance pipe 20 of the thermoacoustic engine 11 located at the uppermost stage. In other words, the first check valve 14 allows the flow toward the thermoacoustic engine 11 located at the uppermost stage and blocks the flow in the opposite direction. The valve opening pressure (set load) of the first check valve 14 is set so as to open when the upstream pressure of the first check valve 14 becomes larger than the downstream pressure, for example.

The second check valve 15 is attached to the connection pipe 12 so that the working fluid flows from the resonance pipe 20 of the thermoacoustic engine 11 located in the upper stage toward the resonance pipe 20 of the thermoacoustic engine 11 located in the lower stage. In other words, the second check valve 15 allows a flow from the thermoacoustic engine 11 located in the upper stage toward the thermoacoustic engine 11 located in the lower stage, and blocks the flow in the opposite direction. For example, the valve opening pressure (set load) of the second check valve 15 is set to open when the upstream pressure of the second check valve 15 becomes larger than the downstream pressure.

The discharge pipe 16 is connected to the resonance pipe 20 (in this embodiment, the straight pipe section 25) of the thermoacoustic engine 11 located at the lowest stage, and the working fluid is inside the resonance pipe 20 of the thermoacoustic engine 11 located at the lowest stage. It is for discharging from. The discharge pipe 16 is composed of a thin pipe having a diameter sufficiently smaller than that of the loop pipe section 24 and the straight pipe section 25. The upstream end of the discharge pipe 16 is preferably connected to a location where the pressure fluctuation in the resonance pipe 20 is the largest with respect to the thermoacoustic engine 11 located at the lowest stage. Further, the upstream end of the discharge pipe 16 is connected to a location away from the engine portion (heating unit 21, stack 22, cooling unit 23) of the thermoacoustic engine 11 with respect to the thermoacoustic engine 11 located at the lowest stage. Is preferred. In the present embodiment, the downstream end of the discharge pipe 16 is connected to the tank 18.

The third check valve 17 is attached to the discharge pipe 16 so that the working fluid flows from the resonance pipe 20 of the thermoacoustic engine 11 located at the lowermost stage toward the tank 18. That is, the third check valve 17 blocks the flow from the tank 18 side toward the thermoacoustic engine 11 located at the lowest stage and allows the flow in the opposite direction. The valve opening pressure (set load) of the third check valve 17 is set so as to open when the upstream pressure of the third check valve 17 becomes larger than the downstream pressure, for example.

The tank 18 is disposed in the discharge pipe 16 downstream of the third check valve 17 and stores the working fluid that has passed through the third check valve 17. The tank 18 is detachably connected to the discharge pipe 16 in order to use the working fluid stored in the tank 18 in another system. In this embodiment, the tank 18 is connected to the downstream end of the discharge pipe 16, but the tank 18 is connected to the discharge pipe 16 and a stop valve is provided on the discharge pipe 16 downstream of the tank 18. Also good.

The operation principle of the thermoacoustic pump 10 according to the present embodiment will be described with reference to FIG. In FIG. 2, the pressure in the resonance tube 20 of the first-stage thermoacoustic engine 11 located in the upper stage is indicated by a thin line, and the pressure in the resonance tube 20 of the second-stage thermoacoustic engine 11 located in the lower stage is indicated by a thick line. Is shown.

Suppose that the working fluid is air. Further, it is assumed that the pressure in the resonance tube 20 of the thermoacoustic engine 11 is atmospheric pressure in the initial state. When the thermoacoustic engine 11 starts self-oscillation from this initial state, periodic pressure fluctuations are generated in the resonance tube 20 of the thermoacoustic engine 11. At this time, in a negative pressure region where the pressure in the resonance pipe 20 of the first stage thermoacoustic engine 11 is lower than atmospheric pressure (at the time of negative pressure), outside air passes from the outside through the suction pipe 13 and the first check valve 14. It flows into the resonance tube 20 of the first stage thermoacoustic engine 11. This is because the upstream pressure (external pressure, that is, atmospheric pressure) of the first check valve 14 becomes higher than the downstream pressure (pressure in the resonance tube 20 of the first stage thermoacoustic engine 11).

Next, when the pressure in the resonance tube 20 of the thermoacoustic engine 11 increases, the pressure in the resonance tube 20 becomes atmospheric pressure or higher. At this time, if the pressure in the resonance pipe 20 of the second stage thermoacoustic engine 11 is lower than the pressure in the resonance pipe 20 of the first stage thermoacoustic engine 11, the compressed air is connected to the connection pipe 12 and the second check valve 15. And flows from the resonance tube 20 of the first-stage thermoacoustic engine 11 to the resonance tube 20 of the second-stage thermoacoustic engine 11. Further, in the positive pressure region (at the time of positive pressure) in which the pressure in the resonance tube 20 of the second stage thermoacoustic engine 11 is equal to or higher than atmospheric pressure, the pressure in the tank 18 is the resonance tube of the second stage thermoacoustic engine 11. When the pressure is lower than 20, the compressed air flows from the resonance pipe 20 of the second stage thermoacoustic engine 11 to the tank 18 through the discharge pipe 16 and the third check valve 17.

When such a cycle is repeated, the average pressure in the resonance tube 20 of the thermoacoustic engine 11 gradually increases, and the pressure amplitude in the resonance tube 20 also increases accordingly. When the pressure state finally reaches the right end in FIG. 2, the upper limit (maximum generated pressure) of the pressure that can be generated by the thermoacoustic pump 10 according to the present embodiment is reached. In the pressure state as shown in the right end of FIG. 2, the pressure in the resonance tube 20 of the first stage thermoacoustic engine 11 does not become lower than the atmospheric pressure, and the first check valve 14 resonates with the first stage thermoacoustic engine 11. This is because the outside air is not sucked into the tube 20. However, if the heating temperature in the heating unit 21 of the thermoacoustic engine 11 is increased, higher pressure can be generated in the resonance tube 20 and the tank 18 of the thermoacoustic engine 11.

That is, the thermoacoustic pump 10 according to the present embodiment uses pressure vibration generated in the resonance tube 20 of the thermoacoustic engine 11, and the outside air when the pressure in the resonance tube 20 of the thermoacoustic engine 11 becomes low. Is sucked into the resonance tube 20 of the thermoacoustic engine 11, and when the pressure in the resonance tube 20 of the thermoacoustic engine 11 becomes high, compressed air is discharged from the resonance tube 20 of the thermoacoustic engine 11 to the tank 18. Functions as a compressor (air compressor) with no moving parts such as pistons.

Note that the tank 18 is not necessarily connected to the discharge pipe 16. That is, if the compressed air is simply flowed without being stored in the tank 18, the thermoacoustic pump 10 functions as a pump (air pump) having no moving parts such as a piston.

In the thermoacoustic pump 10 according to the present embodiment, the resonance tube 20 of the second-stage thermoacoustic engine 11 uses compressed air in a state where the pressure is increased in the resonance tube 20 of the first-stage thermoacoustic engine 11. Since the suction is performed through the connection pipe 12 and the second check valve 15, the average pressure in the resonance pipe 20 of the second-stage thermoacoustic engine 11 is higher than the average pressure in the resonance pipe 20 of the first-stage thermoacoustic engine 11. High pressure. Therefore, the pressure of the compressed air flowing through the discharge pipe 16 and the third check valve 17 to the tank 18 can also be increased. In the second-stage thermoacoustic engine 11, the average pressure in the resonance tube 20 is higher than that in the first-stage thermoacoustic engine 11, so that the pressure amplitude in the resonance tube 20 is also higher than that in the first-stage thermoacoustic engine 11. And higher pressure can be obtained.

By the way, in the thermoacoustic engine 11, when the working fluid filled in the resonance tube 20 is the same, when the pressure in the resonance tube 20 increases, the heat capacity per unit volume of the working fluid increases, and the working fluid is heated and cooled. It will take time. That is, in order to perform efficient pressurization with a configuration in which the thermoacoustic engines 11 are arranged in multiple stages, it is necessary to select the resonance tube 20 that matches the internal pressure of the thermoacoustic engine 11. For this reason, in the present embodiment, as described above, the resonance frequency of the sound wave generated in the resonance tube 20 by increasing the pipe length of the straight tube portion 25 as much as the lower thermoacoustic engine 11 is set to the lower thermoacoustic. The lower the engine 11, the slower the working fluid flow rate is as the lower thermoacoustic engine 11.

In short, according to the thermoacoustic pump 10 according to the present embodiment, the plurality of thermoacoustic engines 11 in which the heating unit 21, the stack 22, and the cooling unit 23 are disposed in the resonance tube 20 filled with the working fluid. A connection pipe 12 for connecting the resonance tubes 20 of the plurality of thermoacoustic engines 11 in multiple stages, a suction pipe 13 connected to the resonance pipe 20 of the thermoacoustic engine 11 located at the uppermost stage, and a suction pipe 13. A suction check valve 14 for allowing a flow toward the thermoacoustic engine 11 located at the uppermost stage and blocking a flow in the reverse direction, and attached to the connecting pipe 12 and from the thermoacoustic engine 11 located at the upper stage to the lower stage. The connection check valve 15 that allows the flow toward the thermoacoustic engine 11 located at the side and blocks the flow in the reverse direction, and the discharge pipe 16 connected to the resonance pipe 20 of the thermoacoustic engine 11 located at the lowermost stage. And attached to the discharge pipe 16 And a discharge check valve 17 that prevents the flow toward the thermoacoustic engine 11 located at the lowermost stage and allows the flow in the reverse direction, and the resonance tube 20 resonates with the thermoacoustic engine 11 located at the lower stage. Since the resonance frequency of the sound wave generated in the tube 20 is set to be lower than the resonance frequency of the sound wave generated in the resonance tube 20 of the thermoacoustic engine 11 located in the upper stage, there is no movable part such as a piston, and durability is improved. When using the thermoacoustic engine 11 which is high, it is possible to provide a pump capable of obtaining a necessary pressure without increasing the heat source temperature.

Also, the thermoacoustic pump 10 according to the present embodiment does not require oil, and no oil is mixed into the compressed air.

In addition, by heating the thermoacoustic engine 11 (heating unit 21) with waste heat (vehicle waste heat, factory waste heat, etc.) generated by another system, a pump that requires almost no maintenance cost is realized.

Furthermore, by using the resonance tube 20 having a resonance frequency corresponding to the operating pressure for each thermoacoustic engine 11, more efficient pressurization and high pressure can be generated.

The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various other embodiments can be adopted.

For example, in the embodiment of FIG. 1, an example is shown in which the number of stages of the thermoacoustic engine 11 is two, but naturally the pressure is further increased by increasing the number of stages of the thermoacoustic engine 11 to three stages and four stages. It is possible to continue. That is, the number of stages of the thermoacoustic engine 11 is not limited to two, but may be three or more. The required pressure can be obtained by changing (adding) the number of stages of the thermoacoustic engine 11 without increasing the heat source temperature of the thermoacoustic engine 11.

Further, as shown in FIG. 3, the resonance pipe 20 is positioned at the lower stage by making the pipe length of the loop pipe portion 24 (that is, the pipe length of the resonance pipe 20) longer as the lower thermoacoustic engine 11. The resonance frequency of the sound wave generated in the resonance tube 20 of the thermoacoustic engine 11 may be set to be lower than the resonance frequency of the sound wave generated in the resonance tube 20 of the thermoacoustic engine 11 located in the upper stage. In FIG. 3, the pipe length in the long side direction of the loop pipe portion 24 having a rectangular loop is increased. However, the pipe length in the short side direction of the loop pipe portion 24 having a rectangular loop may be increased. good.

Further, as shown in FIG. 4, a surge tank 19 for temporarily storing the working fluid may be provided in the connection pipe 12. In FIG. 4, the second check valves 15 are arranged in the connection pipes 12 upstream and downstream of the surge tank 19.

Further, the structure of the thermoacoustic engine 11 is not limited to that of the embodiment of FIG. A modification of the thermoacoustic engine 11 is shown in FIG. As shown in FIG. 5A, the resonance tube 31 has a loop tube portion 32 formed in a loop shape, and the heating portion 21, the stack 22, and the cooling portion 23 are arranged in the loop tube portion 32. In addition, the connecting pipe 12, the suction pipe 13 and the discharge pipe 16 are connected to the loop pipe portion 32. Further, as shown in FIG. 5B, the resonance tube 33 has a straight tube portion 34 formed in a straight line, and the heating portion 21, the stack 22, and the cooling portion 23 are provided on the straight tube portion 34. The connecting pipe 12, the suction pipe 13, and the discharge pipe 16 are connected to the straight pipe portion 34.

In the embodiment of FIG. 1, the resonance frequency of the sound wave generated in the resonance tube 20 is set to be lower as the lower thermoacoustic engine 11 by appropriately changing the pipe length of the resonance tube 20. This is not limited. For example, it is conceivable that the pipe thickness of the resonance tube 20 is appropriately changed (generally, the resonance frequency decreases as the pipe thickness decreases). Although the influence of the change in the pipe thickness of the resonance tube 20 on the resonance frequency is small compared to the case where the pipe length of the resonance pipe 20 is changed, the resonance can be obtained by appropriately changing the pipe thickness of the resonance pipe 20. It is possible to set the resonance frequency of the sound wave generated in the tube 20 to be lower for the thermoacoustic engine 11 on the lower side.

DESCRIPTION OF SYMBOLS 10 Thermoacoustic pump 11 Thermoacoustic engine 12 Connection pipe 13 Intake pipe 14 Inhalation check valve (first check valve)
15 Check valve for connection (second check valve)
16 Discharge pipe 17 Discharge check valve (third check valve)
18 Tank 19 Surge Tank 20 Resonance Tube 21 Heating Unit 22 Stack 23 Cooling Unit

Claims

A plurality of thermoacoustic engines in which a heating unit, a stack, and a cooling unit are disposed in a resonance tube filled with a working fluid; a connection tube that connects the resonance tubes of the plurality of thermoacoustic engines in multiple stages; A suction pipe connected to the resonance pipe of the thermoacoustic engine located in the upper stage, and attached to the suction pipe, allowing a flow toward the thermoacoustic engine side located in the uppermost stage and preventing a reverse flow. And a check valve for suction that is attached to the connecting pipe and that allows a flow from the thermoacoustic engine side located in the upper stage toward the thermoacoustic engine side located in the lower stage and prevents a reverse flow A check valve, a discharge pipe connected to the resonance pipe of the thermoacoustic engine located at the lowermost stage, and attached to the discharge pipe to prevent a flow toward the thermoacoustic engine located at the lowermost stage; A discharge check valve that allows reverse flow For example,
The resonance tube is set so that a resonance frequency of sound waves generated in the resonance tube of the thermoacoustic engine located in the lower stage is lower than a resonance frequency of sound waves generated in the resonance tube of the thermoacoustic engine located in the upper stage. A thermoacoustic pump characterized by that.
By making the pipe length of the resonance tube longer as the thermoacoustic engine on the lower stage side, the resonance tube has the resonance frequency of the sound wave generated in the resonance tube of the thermoacoustic engine located in the lower stage on the upper stage. The thermoacoustic pump according to claim 1, wherein the thermoacoustic pump is set to be lower than a resonance frequency of a sound wave generated in the resonance tube of the thermoacoustic engine.
The thermoacoustic pump according to claim 1 or 2, further comprising a tank that is disposed in the discharge pipe downstream of the discharge check valve and stores the working fluid that has passed through the discharge check valve.
The thermoacoustic pump according to any one of claims 1 to 3, further comprising a surge tank disposed in the connection pipe.