Fluid device

Abstract

To provide a fluid device which utilizes acoustic convergence to condense fine particles in a liquid and enables easy operation control.SOLUTION: A fluid device includes: a convergence part which has a passage for causing a liquid containing particles to flow and converges the particles on a cross section of the passage while causing the liquid to flow; and a control unit which controls operation of the convergence part. The convergence part includes: a passage member having a first passage and a second passage serving as passages in which the fluid flows; and a vibration part which causes the passage member to vibrate. The vibration part has: a diaphragm in which the passage member is attached to a major surface; and a vibrator which causes the diaphragm to vibrate in a thickness direction of the diaphragm. The control unit causes the vibrator to generate composite vibration of first ultrasonic vibration having a first frequency and causing standing waves in the first passage and second ultrasonic vibration having a second frequency and causing standing waves in the second passage.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a fluid device.

Background Art

[0002] Conventionally, a fluid device for acoustically converging fine particles in a fluid (liquid) has been known (see, for example, Patent Document 1). The fluid device described in Patent Document 1 includes a flow path member through which a fluid flows and an ultrasonic element provided in the flow path. By applying ultrasonic vibration to the fluid flowing in the flow path from the ultrasonic element, fine particles dispersed in the fluid can be converged (concentrated) near the center of the flow path.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The fluid device using acoustic convergence as described in Patent Document 1 above has the following problems. For example, in a fluid device using acoustic convergence, when the size of the flow path member is increased, the ultrasonic element that applies ultrasonic vibration to the inside of the flow path also needs to be increased in size, and it is likely to be difficult to manufacture the device. Therefore, when increasing the throughput in a fluid device using acoustic convergence, usually, increasing the number of flow paths and performing parallel processing are considered.

[0005] On the other hand, in a fluid device using acoustic convergence, usually, each flow path has an ultrasonic element, and the frequency of the ultrasonic wave applied from the ultrasonic element for each flow path is adjusted. Therefore, in order to increase the number of fluid devices and control a plurality of fluid devices simultaneously, the adjustment of each ultrasonic element tends to be complicated, and improvement has been demanded.

[0006] The present invention has been made in view of such circumstances, and an object thereof is to provide a fluid device that uses acoustic focusing to concentrate fine particles in a liquid and is easy to control the operation.

Means for Solving the Problems

[0007] In order to solve the above problems, the inventor considered that by applying ultrasonic vibrations from a single ultrasonic element (vibrator) to a plurality of flow paths, the number of vibrators that need to be adjusted is reduced and the control becomes easier. However, as the study progressed, it was found that the appropriate ultrasonic vibrations are different for each flow path, and even if ultrasonic vibrations of a single frequency are applied to a plurality of flow paths, they do not show the desired behavior.

[0008] For example, even if flow paths having the same shape and the same size are prepared as a plurality of flow paths, the actual dimensions of the flow paths are different due to manufacturing errors. Due to this difference in actual dimensions, it is considered that the appropriate frequencies for ultrasonic vibrations for acoustic focusing are different for each flow path. In addition, due to various influences such as the arrangement (relative position) of each flow path with respect to the vibrator and the change in the liquid temperature of the liquid flowing inside, it was considered difficult to set an appropriate frequency.

[0009] As a result of intensive studies on the above problems, the inventor found that by applying ultrasonic vibrations of a plurality of appropriately set frequencies to a plurality of flow paths instead of a single ultrasonic vibration, appropriate acoustic focusing can be achieved in each flow path, and completed the invention.

[0010] In order to solve the above problems, one aspect of the present invention includes the following aspects.

[0011] [1] A fluid device includes a flow path for flowing a liquid containing particles, a converging section for converging the particles in a cross-section of the flow path while flowing the liquid, and a control section for controlling the operation of the converging section. The converging section includes a flow path member having a first flow path and a second flow path through which the liquid flows as the flow path, and a vibrating section for vibrating the flow path member. The vibrating section includes a diaphragm to which the flow path member is attached on a main surface, and a vibrator for vibrating the diaphragm in a thickness direction of the diaphragm. The control section causes a combined vibration of a first ultrasonic vibration having a first frequency and generating a standing wave in the first flow path and a second ultrasonic vibration having a second frequency and generating a standing wave in the second flow path to occur in the vibrator.

[0012] [2] The fluid device according to [1], wherein the control section causes an ultrasonic vibration of a combined waveform of a vibration waveform of the first ultrasonic vibration and a vibration waveform of the second ultrasonic vibration to occur in the vibrator.

[0013] [3] The fluid device according to [1], wherein the control section changes a frequency of vibration caused in the vibrator between the first frequency and the second frequency within a unit time.

[0014] [4] The fluid device according to any one of [1] to [3], wherein the cross-section of the first flow path is circular.

[0015] [5] The fluid device according to any one of [1] to [3], wherein the cross-section of the first flow path is rectangular, and the control section uses, as the first ultrasonic vibration, a combined vibration of a first component that is an ultrasonic vibration having a half wavelength equal to a length of a long side of the rectangle and a second component that is an ultrasonic vibration having a half wavelength equal to a length of a short side of the rectangle.

[0016] [6] The control unit includes a storage unit that stores the correspondence between the dimensions of the first flow path and the first frequency, an input means for inputting the actual dimensions of the first flow path, a determination unit that determines the first ultrasonic vibration based on the actual dimensions and the correspondence, and a signal creation unit that creates a drive signal for causing the combined vibration to occur in the vibrator. The fluid device according to any one of [1] to [5].

[0017] [7] The fluid device according to any one of [1] to [6], further comprising a detection means for detecting the temperature of the liquid flowing through the first flow path, wherein the control unit includes a measurement unit that obtains the temperature from a signal transmitted from the detection means, a storage unit that stores the correspondence between the temperature and the first frequency, a determination unit that determines the first ultrasonic vibration based on the temperature and the correspondence, and a signal creation unit that creates a drive signal for causing the combined vibration to occur in the vibrator.

[0018] [8] The control unit includes a storage unit that stores the correspondence between the upper limit temperature of the temperature range in which the liquid flowing through the first flow path can change in temperature and the first frequency, and the correspondence between the lower limit temperature of the temperature range and the first frequency, a determination unit that determines, as the first ultrasonic vibration, a combined vibration of a high-temperature ultrasonic vibration determined based on the correspondence between the upper limit temperature and the first frequency and a low-temperature ultrasonic vibration determined based on the correspondence between the lower limit temperature and the first frequency, and a signal creation unit that creates a drive signal for causing the combined vibration to occur in the vibrator. The fluid device according to any one of [1] to [7].

[0019] [9] On the downstream side of the vibration unit, the first flow path has a first branch flow path through which a first liquid component that flows through the central portion of the cross section and in which the particles are concentrated flows in, and a second branch flow path through which a second liquid component that flows through the peripheral portion of the cross section flows in. The fluid device according to any one of [1] to [8].

Advantages of the Invention

[0020] According to the present invention, there is provided a fluid device that utilizes acoustic focusing to concentrate fine particles in a liquid, and can provide a fluid device that is easy to control in operation.

Brief Description of the Drawings

[0021]

Figure 1

Figure 2

Figure 3

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Figure 10

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Figure 12

Figure 13

Figure 14

Figure 15

Embodiments for Carrying Out the Invention

[0022] Hereinafter, with reference to FIGS. 1 to 6, the fluid device according to this embodiment will be described. In all the following drawings, for ease of viewing the drawings, the dimensions, ratios, etc. of each component are appropriately different.

[0023] 《Fluid Device》 FIG. 1 is an explanatory diagram showing the fluid device 100 of this embodiment. As shown in FIG. 1, the fluid device 100 of this embodiment includes a supply unit 10, a converging unit 20A, and a control unit 30. The fluid device 100 has a function of converging the fine particles P in a cross section orthogonal to the flow direction of the liquid L while flowing the liquid L containing the fine particles P.

[0024] [Supply Unit] The supply unit 10 stores the liquid L containing the fine particles P and supplies it to the downstream side. The supply unit 10 includes a storage unit 11, a pipe 12, and a pump 13.

[0025] The storage unit 11 is a container for storing the liquid L. Although only one storage unit 11 is shown in FIG. 1, the present invention is not limited to this, and a plurality of storage units 11 may be prepared so that the discharge source can be switched according to the remaining amount of the liquid L.

[0026] The pipe 12 is a pipeline through which the liquid L discharged from the storage unit 11 flows inside. The pipe 12 includes a main pipe 120 having one end connected to the storage unit 11, branch pipes 121, 122, 123 branching from the main pipe 120 on the downstream side of the main pipe 120, and a branch unit 125 for branching the liquid L from the main pipe 120 to the branch pipes 121, 122, 123. In this embodiment, it is assumed that the liquid L branches into three branch pipes 121, 122, 123 at the branch unit 125, but the present invention is not limited to this, and a configuration in which the liquid L branches into two branch pipes or a configuration in which the liquid L branches into four or more branch pipes may be used.

[0027] The other end of the pipe 12 (the other ends of the branch pipes 121, 122, 123) is connected to the converging unit 20A.

[0028] The pump 13 is provided in the flow path of the pipe 12 and causes the liquid L in the pipe 12 to flow downstream. The pump 13 preferably has a structure in which the fine particles P contained in the liquid L are less likely to be blocked. As such a pump 13, for example, a tube pump or a diaphragm pump can be preferably used.

[0029] [Converging section] The converging section 20A has a flow path for flowing the liquid L supplied from the supply section 10, and has a function of converging the fine particles P in the cross section of the flow path while the liquid L is flowing. Note that the "cross section of the flow path" refers to the cross section on a virtual plane orthogonal to the extending direction of the flow path.

[0030] The converging section 20A includes a flow path member 21 and a vibrating section 22.

[0031] (Flow path member) The flow path member 21 has a flow path through which the liquid L flows. In the fluid device 100 of the present embodiment, the flow path member 21 includes three members: a first flow path member 211, a second flow path member 212, and a third flow path member 213. The first flow path member 211 has a first flow path 211a through which the liquid L flows. Similarly, the second flow path member 212 has a second flow path 212a, and the third flow path member 213 has a third flow path 213a. A branch pipe 121 is connected to the first flow path member 211. Similarly, a branch pipe 122 is connected to the second flow path member 212, and a branch pipe 123 is connected to the third flow path member 213.

[0032] That is, in the fluid device 100, three flow paths are connected in parallel. In FIG. 1, the first flow path member 211, the second flow path member 212, and the third flow path member 213 are arranged substantially in parallel.

[0033] FIG. 2 is a cross-sectional view of the converging section 20A. As shown in FIG. 2, in the first flow path member 211 and the second flow path member 212 included in the flow path member 21, the cross-sectional shapes of the respective flow paths (the first flow path 211a and the second flow path 212a) are circular. Also in the third flow path member 213 (not shown), the cross-sectional shape of the third flow path 213a is preferably circular.

[0034] (Vibrating part) The vibrating part 22 is provided commonly for each flow path connected in parallel, and by vibrating the flow path member 21, ultrasonic vibration is supplied to each flow path. The vibrating part 22 has a diaphragm 221 and a vibrator 222.

[0035] The diaphragm 221 is a plate-like member presenting a rectangle when viewed from the normal direction of the diaphragm 221, and the flow path member 21 is attached to the main surface 221a. The "main surface" is the surface of the diaphragm 221 facing the outside of the vibrating part 22 and is the surface exposed in the field of view from the normal direction.

[0036] The flow path member 21 is attached to the diaphragm 221 via an adhesive layer 223. In the field of view in the normal direction of the diaphragm 221, the diaphragm 221 overlaps a part of the flow path member 21. The length of the portion where the diaphragm 221 and the flow path member 21 are in contact (the length in the flow direction of the flow path member 21 in contact with the diaphragm 221) is preferably relatively long to promote acoustic convergence. For example, when using a SUS tube with an inner diameter of about 1 mm as the flow path member, it is preferable that the diaphragm 221 and the flow path member 21 (SUS tube) are in contact for 20 mm or more, and more preferably 40 mm or more.

[0037] The vibrator 222 vibrates the diaphragm 221 in the thickness direction of the diaphragm 221. Thereby, the vibrating part 22 can vibrate the flow path member 21 in the thickness direction of the diaphragm 221.

[0038] As the vibrator 222, a known vibrator can be used as an ultrasonic vibrator that converts high-frequency power into ultrasonic vibration. As ultrasonic vibrators, two types, electrostrictive vibrators and magnetostrictive vibrators, are known. In the vibrator 222, an electrostrictive vibrator capable of generating relatively high-frequency ultrasonic vibration is preferable. Examples of electrostrictive vibrators include piezo elements using lead zirconate titanate (PZT) and vibrators using lithium niobate (LiNbO3).

[0039] Similar to known fluid devices based on the principle of acoustic focusing, in the fluid device 100, the vibrator 222 (vibrating portion 22) emits ultrasonic vibrations that generate a standing wave W in the flow path by controlling the vibration state of the vibrating portion 22 by a control unit 30 described later. As a result, an acoustic radiation force F directed from the inner wall of the flow path toward the center of the flow path is applied to the fine particles P dispersed in the liquid L in the flow path member 21, converging (acoustic focusing) the fine particles P near the center of the cross-section of the flow path.

[0040] At this time, in the flow path member 21 having a circular flow path shape, the standing wave W is generated isotropically in the cross-sections of the first flow path 211a, the second flow path 212a, and the third flow path 213a. Therefore, in the flow path member 21, it is easy to converge the fine particles P to the center of the flow path.

[0041] The "ultrasonic vibrations that generate a standing wave W in the flow path" may be obtained theoretically or experimentally through preliminary experiments.

[0042] [Control Unit] The control unit 30 controls the operation of the converging portion 20A. Specifically, the control unit 30 controls the operation of the vibrator 222 by creating a drive signal for operating the vibrator 222 of the vibrating portion 22 and supplying it to the vibrator 222. As a result, the above-described acoustic focusing occurs in the converging portion 20A, and the fine particles P dispersed in the liquid L are converged. Note that the control unit 30 may control the pump 13 included in the supply unit 10.

[0043] Here, through the inventor's research, it has been found that the above-mentioned "ultrasonic vibration that generates a standing wave W in the flow path" varies depending on various conditions, such as the shape and size of the flow path, the temperature of the liquid L flowing in the flow path, and the relative position of the flow path with respect to the vibrator 222. For example, as shown in FIG. 1, when applying ultrasonic vibration from a single vibrator to a plurality of flow paths, even if flow paths of the same shape and the same size are prepared as the plurality of flow paths, the actual dimensions of the flow paths are different due to manufacturing errors. Due to this difference in actual dimensions, it is considered that the appropriate frequency for the ultrasonic vibration for acoustic convergence is different for each flow path. In addition, due to various influences such as the arrangement (relative position) of each flow path with respect to the vibrator and the change in the liquid temperature of the liquid flowing inside, it has been considered difficult to set an appropriate frequency.

[0044] Therefore, in the fluid device 100, the control unit 30 determines the ultrasonic vibration that generates a standing wave for each flow path, and causes the vibrator to generate a combined vibration of the ultrasonic vibrations that generate standing waves in each flow path. In the relationship between the first flow path 211a and the second flow path 212a, the control unit 30 creates a drive signal that causes the vibrator to generate a combined vibration of a first ultrasonic vibration having a first frequency and generating a standing wave in the first flow path 211a and a second ultrasonic vibration having a second frequency and generating a standing wave in the second flow path 212a, and supplies it to the vibrator 222.

[0045] FIG. 3 is a block diagram for explaining the configuration of the control unit 30. The control unit 30 includes an input means 31, a temperature sensor (detection means) 32, and a control device 33.

[0046] The input means 31 can include an input device for inputting an instruction to the control device 33, a power switch of the control device 33, and the like. Examples of the instruction input from the input means 31 include · The actual dimensions of each flow path · The width of the manufacturing error with respect to the design value of the flow path (the upper limit value and the lower limit value assumed as the dimensions of the flow path) · The correspondence relationship between the dimensions of the first flow path 211a and the frequency of the first ultrasonic vibration (the first frequency) that generates a standing wave in the first flow path 211a · The temperature range in which the liquid L can undergo temperature changes (the upper limit value and the lower limit value assumed as the temperature of the liquid L) · The correspondence between the temperature of the liquid L and the frequency of the first ultrasonic vibration that generates a standing wave in the first flow path 211a (the first frequency) · The same correspondence as described above for the second and third flow paths can be mentioned.

[0047] Also, when the frequency of the first ultrasonic vibration has been confirmed by a preliminary experiment, the frequency of the first ultrasonic vibration may be input from the input means 31.

[0048] The temperature sensor 32 detects the temperature of the liquid L flowing in the flow path. In FIG. 1, one temperature sensor 32 is provided in the main pipe 120 of the pipe 12, and it is assumed to detect the temperature of the liquid L in the main pipe 120. In this case, it is considered that the liquid L flowing through the first flow path 211a, the second flow path 212a, and the third flow path 213a all has the same temperature.

[0049] Also, the temperature sensor 32 may be provided in each of the branch pipes 121, 122, and 123. Furthermore, the temperature sensor 32 may be provided in the flow path member 21. At this time, the temperature sensor 32 may be provided upstream of the vibration part 22, or may be provided downstream of the vibration part 22.

[0050] The control device 33 creates a drive signal for the vibrator 222 based on the detection result by the temperature sensor 32 and the instruction input from the input means 31, and supplies it to the vibrator 222. The control device 33 includes a measurement unit 331, a storage unit 332, a determination unit 333, and a signal creation unit 334. For the sake of convenience of explanation, the measurement unit 331, the storage unit 332, the determination unit 333, and the signal creation unit 334 are separately illustrated, but these are processing blocks and do not necessarily need to be physically separated within the control device 33.

[0051] The measurement unit 331 receives the detection result detected by the temperature sensor 32 as an electrical signal, and calculates and obtains the temperature of the liquid L from the received electrical signal. The measurement unit 331 may receive the detection results continuously detected by the temperature sensor 32 without interruption and continuously obtain the temperature of the liquid L, or may receive the detection results intermittently and obtain the temperature of the liquid L intermittently.

[0052] The storage unit 332 stores the above correspondence relationship input from the input means 31. The correspondence relationship may be stored in advance. In FIG. 3, the storage unit 332 is described as a component of the control device 33, but it is not limited to this. An external storage medium may be used as the storage unit 332. The above correspondence relationship can be stored in the form of a mathematical formula or a look-up table.

[0053] The determination unit 333 receives information related to at least one of "the dimensions of the flow path" and "the temperature of the liquid", such as the temperature of the liquid L obtained by the measurement unit 331, the actual dimensions of the flow path input from the input means 31, the width of the manufacturing error with respect to the design value of the flow path stored in the storage unit 332, and the temperature range in which the liquid L can change in temperature. The determination unit 333 determines the ultrasonic vibration that generates a standing wave in the flow path based on these information and the correspondence relationship stored in the storage unit 332. Specifically, the determination unit 333 determines a first ultrasonic vibration having a first frequency and generating a standing wave in the first flow path 211a, a second ultrasonic vibration having a second frequency and generating a standing wave in the second flow path 212a, and a third ultrasonic vibration having a third frequency and generating a standing wave in the third flow path 213a.

[0054] When the determination unit 333 obtains information on the temperature range in which the liquid L can change in temperature, the determination unit 333 may determine the combined vibration of the high-temperature ultrasonic vibration determined based on the correspondence relationship between the upper limit temperature of the temperature range and the first frequency and the low-temperature ultrasonic vibration determined based on the correspondence relationship between the lower limit temperature and the first frequency as the first ultrasonic vibration. The combined vibration can be created by the method described later.

[0055] The signal generation unit 334 creates a drive signal that causes the combined vibration of the first to third ultrasonic vibrations determined by the determination unit 333 to occur in the vibrator 222.

[0056] The signal generation unit 334 may obtain a composite waveform of the vibration waveforms of the first ultrasonic vibration, the second ultrasonic vibration, and the third ultrasonic vibration, and create a drive signal that causes the ultrasonic vibration having the composite waveform to occur in the vibrator 222.

[0057] FIG. 4 is an explanatory diagram for explaining the composite waveform. FIG. 4(a) is a graph showing the waveforms of the ultrasonic vibrations UV1 to UV3 of three frequencies generated in the vibrator 222, and FIG. 4(b) is a graph showing the result of Fourier-transforming the waveforms of the ultrasonic vibrations UV1 to UV3.

[0058] As shown in FIGS. 4(a) and 4(b), for example, the waveforms of three ultrasonic vibrations (the first ultrasonic vibration UV1, the second ultrasonic vibration UV2, and the third ultrasonic vibration UV3) with different frequencies are Fourier-transformed respectively, and after creating a peak by overlapping the obtained transformed peaks, an inverse Fourier transform is performed to obtain a composite waveform CW.

[0059] Here, even if a single-frequency ultrasonic vibration UV1 is generated in the vibrator 222, as shown by the waveform after Fourier transform, the ultrasonic vibration UV1 has a frequency spread (peak width PW) of a certain width. Also, even if the frequencies of the ultrasonic vibrations that cause standing waves differ due to manufacturing errors during the production of the flow path or temperature changes in the liquid L, these differences are minute. Therefore, it is considered that large differences are unlikely to occur in the frequencies of the ultrasonic vibrations before synthesis, and the peaks after the above Fourier transform often overlap with each other.

[0060] Thus, it can be considered that the synthesized waveform CW includes, in addition to the frequencies of the peaks of the three original ultrasonic vibrations, the vibration components of the frequencies between the peaks of the three ultrasonic vibrations. By causing the ultrasonic vibration having the thus obtained synthesized waveform CW to occur in the vibrator 222, a standing wave can be generated in the flow path even if there are manufacturing errors in the flow path or temperature changes in the liquid L.

[0061] In order to appropriately generate a standing wave in the flow path, when obtaining the synthesized waveform CW, the amplitudes of the three ultrasonic vibrations that are the basis of the synthesis may be appropriately adjusted.

[0062] In addition to the process of obtaining the synthesized waveform CW by combining the ultrasonic vibrations as described above, the signal generation unit 334 may create a drive signal that changes the frequency of the vibration generated in the vibrator 222 between a first frequency, a second frequency, and a third frequency within a unit time. Here, the "unit time" is a time of 100 milliseconds or less, and can be set within the range of 0.001 milliseconds or more and 100 milliseconds or less.

[0063] The unit time for changing the frequency as described above can be set in consideration of the time during which the fine particles exist in the flow path. For example, when the liquid in the flow path forms a laminar flow, it is known that the flow velocity at the center of the laminar flow is about twice the average flow velocity. Considering such a difference in the flow velocity of the liquid, if it is calculated that the liquid near the center of the flow path passes through the flow path member in 240 milliseconds, in order to apply two types of ultrasonic vibrations, the unit time is preferably 100 milliseconds or less. Thereby, it is possible to surely acoustically converge the fine particles flowing with the fastest liquid in the flow path with two types of ultrasonic vibrations.

[0064] Furthermore, it is preferable to set the unit time obtained as described above even shorter to average the effects of the plurality of types of ultrasonic vibrations to be applied. In the above example, by setting the unit time for vibration switching to 10 milliseconds, two types of ultrasonic vibrations can be applied to the fine particles passing through the flow path 10 times or more each. From the same concept, the unit time is preferably, for example, 1 millisecond.

[0065] The lower limit value of the unit time may be set from the period of the ultrasonic vibration to be applied. For example, since one period of ultrasonic vibration of 1 MHz (1000 kHz) is 0.001 milliseconds, it is conceivable to set the unit time to 0.001 milliseconds or more.

[0066] When creating a drive signal that changes the vibration frequency over time as described above, the drive signal handled by the control device 33 is always of one type. Therefore, compared with the case where the control device 33 handles a plurality of drive signals simultaneously and creates a drive signal of the composite waveform CW, the power consumption can be reduced, and the drive heat generation of the device can be suppressed.

[0067] Also, when vibrating a plurality of flow path members 21 with one vibrator 222, even if the same material is used as the plurality of flow path members, it is conceivable that the ultrasonic vibrations that generate standing waves in the pipe are different due to manufacturing errors. Furthermore, when the thickness of the vibrator 222 varies due to manufacturing errors, there is a possibility that the same vibration cannot be supplied to the flow path members commonly attached to the vibrator 222. In such a case, it is likely to be difficult to obtain the composite waveform CW and supply the ultrasonic vibration corresponding to the composite waveform CW to the flow path members.

[0068] On the other hand, when changing the vibration frequency over time as described above, it is easy to find conditions that enable appropriate acoustic convergence in all flow path members, and the control becomes easy.

[0069] As an example, when applying vibrations of two types of vibration frequencies to a plurality of flow path members 21, the vibration frequencies can be set as follows.

[0070] First, calculate the theoretical resonance frequency of the flow path member 21 by a known analysis method such as finite element analysis. Next, while flowing a liquid containing fine particles through a plurality of flow path members 21, perform a preliminary experiment of applying vibrations at frequencies within ±10% of the obtained resonance frequency to determine a plurality (for example, two types) of vibration frequencies at which the fine particles converge appropriately. By changing the vibration of the frequency obtained in this way over time, for example, in 1 millisecond, and commonly applying it from one vibrator 222 to a plurality of flow path members 21, it becomes possible to preferably cause acoustic convergence in the plurality of flow path members 21.

[0071] The control unit 30 supplies the drive signal created as described above to the vibrator 222 and drives the vibrator 222. As shown in FIG. 2, the vibrator 222 generates ultrasonic vibrations corresponding to the composite waveform CW and vibrates the flow path member. In each flow path, standing waves W1, W2 are generated by ultrasonic components included in the composite waveform CW and having frequencies corresponding to each flow path. Thereby, in the fluid device 100, acoustic convergence can be realized.

[0072] FIG. 5 is an explanatory diagram showing the configuration on the downstream side of the flow path member 21. Inner pipes 215 are inserted into the first flow path member 211, the second flow path member 212, and the third flow path member 213, respectively, on the downstream side of the flow path member 21, forming a branch structure.

[0073] One end opening of the inner pipe 215 is arranged at the center of the cross section of the flow path of each flow path member, forming a double pipe structure with each flow path member. The inner pipe 215 is drawn out to the outside through a through hole 215a that penetrates the pipe wall of each flow path member.

[0074] In the liquid L flowing in the flow path member 21, the fine particles P are acoustically converged by the vibration unit 22. As a result, the liquid L flows downstream in a state generally divided into a first liquid component L1 in which the fine particles P are concentrated and flowing through the central portion of the cross section of the flow path and a second liquid component L2 flowing through the peripheral portion of the cross section.

[0075] By disposing the inner tube 215 in such a liquid L, the first liquid component L1 efficiently flows into the inner tube 215 and is separated from the second liquid component L2 that does not flow into the inner tube 215. The flow path inside the inner tube 215 corresponds to the "first branched flow path" in the present invention, and the flow path outside the inner tube 215 where the second liquid component L2 flows corresponds to the "second branched flow path" in the present invention.

[0076] Note that the fluid device 100 as described above may be used alone or a plurality of them may be connected and used. A fluid device obtained by abstracting the above-described supply unit is prepared on the downstream side, and the first liquid component L1 discharged from the first branched flow path of the upstream fluid device 100 is supplied to the first flow path member on the downstream side, whereby the upstream fluid device can be treated as the supply unit of the downstream fluid device. Thereby, an apparatus configuration in which fluid devices are connected in series can be achieved, and the concentration of particles can be advanced exponentially.

[0077] For example, in the converging portion 20A, the fine particles P dispersed in the liquid L are converged in a region that is one-tenth of the flow path cross-section to form the first liquid component L1, and the first liquid component L1 is drawn into the inner tube 215. As a result, the fine particles P in the liquid L are concentrated 10 times. Therefore, in an apparatus in which three fluid devices are connected in series, the fine particles P in the liquid L can be concentrated 1000 times by passing the entire apparatus once.

[0078] In the fluid device 100 configured as described above, ultrasonic vibration is applied from the common vibration unit 22 to a plurality of flow paths connected in parallel, and the ultrasonic vibration is set as the synthetic vibration as described above. Thereby, the apparatus configuration is simplified, and a standing wave can be appropriately generated in each flow path to enable acoustic convergence.

[0079] Therefore, in the fluid device 100 configured as described above, when concentrating the fine particles P in the liquid L using acoustic convergence, the operation control becomes easy.

[0080] In addition, in the present embodiment, the flow path member is a pipe having a circular cross section, but the present invention is not limited to this. The cross-sectional shape of the flow path of the flow path member may be various shapes such as a rectangle and an ellipse in addition to a circle.

[0081] In addition, in the present embodiment, the flow path member 21 has the first flow path member 211, the second flow path member 212, and the third flow path member 213, but the present invention is not limited to this. FIG. 6 is an explanatory view of a fluid device according to a modified example, and is a view corresponding to FIG. 2.

[0082] The converging portion 20B included in the fluid device 110 shown in FIG. 6 has a flow path for flowing the liquid L supplied from the supply portion 10 (see FIG. 1), and has a function of converging the fine particles P in the cross section of the flow path while flowing the liquid L. The converging portion 20B has a flow path member 25 and a vibrating portion 22.

[0083] The flow path member 25 is a plate-like member having a first flow path 251a and a second flow path 252a. The flow path member 25 is formed by processing a single substrate 250 to form the first flow path 251a and the second flow path 252a, and a plurality of flow paths are provided in one flow path member. The flow path member 25 may further have a flow path.

[0084] Branching pipes of the supply portion 10 are respectively connected to the respective flow paths. Such a configuration can be understood by referring to FIG. 1. That is, in the fluid device 110, a plurality of flow paths are connected in parallel.

[0085] The cross-sectional shapes of the first flow path 251a and the second flow path 252a are rectangular.

[0086] In such a fluid device 110, the control unit 30 (see FIG. 3) creates a composite vibration that is a first ultrasonic vibration that generates a standing wave in the first flow path 251a, which is a first component that is an ultrasonic vibration having a half wavelength equal to the length of the long side of the rectangle that is the cross-sectional shape of the first flow path 251a, and a second component that is an ultrasonic vibration having a half wavelength equal to the length of the short side of the rectangle.

[0087] Information on the long side and short side of the rectangle may be input from the input means 31 or may be stored in the storage unit 332 in advance.

[0088] In the determination unit 333, the lengths of the long side and short side of the rectangle are respectively treated as the actual dimensions of the first flow path 251a, and the first component and the second component are determined by the above-described processing. The signal generation unit 334 obtains the combined vibration of the obtained first component and second component and uses it as the first ultrasonic vibration.

[0089] Similarly, in the second flow path 252a, processing is performed to obtain the combined vibration of the first component and the second component as the second ultrasonic vibration.

[0090] In the signal generation unit 334, using the obtained first ultrasonic vibration and second ultrasonic vibration, a drive signal that generates a combined vibration by the above-described processing is created. By supplying the obtained drive signal to the vibrator 222, also in the fluid device 110, a standing wave W corresponding appropriately to the first component and the second component is generated in each flow path, making acoustic focusing possible.

[0091] Note that when creating the above drive signal, after obtaining the first component and the second component of each flow path and first obtaining the combined vibration of only the first components (first combined vibration) and the combined vibration of the second components (second combined vibration), the combined vibration of the first combined vibration and the second combined vibration may be obtained to obtain the combined vibration to be generated in the vibrator. Since the obtained combined vibration includes a component of vibration that generates a standing wave in the flow path, by creating a drive signal that generates such a combined vibration and inputting it to the vibrator, it becomes possible to suitably generate a standing wave in the flow path.

[0092] In FIG. 6, the standing wave corresponding to the first component generated in the first flow path 251a is denoted by reference sign W11, and the standing wave corresponding to the second component is denoted by reference sign W12. Also, the standing wave corresponding to the first component generated in the second flow path 252a is denoted by reference sign W21, and the standing wave corresponding to the second component is denoted by reference sign W22.

[0093] Therefore, even in the fluid device 110 configured as described above, when concentrating the fine particles P in the liquid L by utilizing acoustic focusing, it becomes possible to easily control the operation.

[0094] Also, in the present embodiment, the flow path member has the first flow path 211a, the second flow path 212a, and the third flow path 213a, and the combined vibration of the first to third ultrasonic vibrations that generate standing waves in each flow path is generated in the vibrator 222. However, the present invention is not limited to this. When the flow path member has even more flow paths, the ultrasonic vibrations that generate standing waves in each flow path are obtained, and the combined vibration of all the obtained ultrasonic vibrations is generated in the vibrator. Thus, similar to the above description, concentration using acoustic focusing can be performed in each flow path.

[0095] Also, in the above embodiment, it has been described as a configuration in which a plurality (three) of flow paths are provided in one vibrator and each flow path is connected in parallel. However, the present invention is not limited to this.

[0096] Explaining using the reference numeral of the fluid device 100, for example, a configuration in which the first flow path member 211, the second flow path member 212, and the third flow path member 213 provided in one vibrating unit 22 are connected in series may be adopted. In a fluid device having such a configuration, the downstream end portion of the first flow path member 211 and the upstream end portion of the second flow path member 212 are connected by a pipe (not shown), and the downstream end portion of the second flow path member 212 and the upstream end portion of the third flow path member 213 are connected by a pipe (not shown).

[0097] In the above fluid device, the liquid L is acoustically focused in the first flow path member 211 and discharged as the first liquid component L1 from the inner pipe 215 of the first flow path member 211. The discharged first liquid component L1 is supplied from the upstream side of the second flow path member 212 and discharged as the first liquid component L1 that is further acoustically focused in the second flow path member 212. Similarly, the first liquid component L1 discharged from the second flow path member 212 is further acoustically focused and discharged in the third flow path member 213.

[0098] As a result, in the above fluid device, the device configuration can be such that the flow paths for acoustic focusing are connected in series, and the concentration of particles can be advanced exponentially.

[0099] Even in such a fluid device with this device configuration, by applying the above-described combined vibration from a common vibrating part to a plurality of flow paths, the device configuration can be simplified, and appropriate standing waves can be generated in each flow path to enable acoustic focusing. Therefore, even in a fluid device with the above configuration, when concentrating fine particles in a liquid using acoustic focusing, the operation control becomes easy.

[0100] As described above, the preferred embodiments of the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to such examples. The various shapes, combinations, etc. of the constituent members shown in the above examples are merely examples, and various modifications can be made based on design, specifications, etc. without departing from the gist of the present invention.

Example

[0101] Hereinafter, the present invention will be described by way of examples, but the present invention is not limited to these examples.

[0102] (Evaluation 1) In Evaluation 1, cylindrical pipes with different inner diameters were used as flow path members, and a PZT element was used as a vibrator. The following three types of pipes were commonly attached to the PZT element, and ultrasonic vibration was applied from the PZT element in a state where the following liquid was supplied, and the state of acoustic focusing was observed. The experimental conditions were as follows. (Conditions) Fine particles: Fluorescent polystyrene particles (diameter 15 μm) Liquid: Aqueous dispersion of polystyrene particles (concentration 1.0×10 4 particles / mL) Flow rate of liquid: 10 mL / min Vibrator: PZT element (70×40 mm, thickness 2 mm, manufactured by Fuji Ceramics Co., Ltd.) Drive voltage: 30 Vpp Pipes: SUS tubes with inner diameters of 0.75 mm (flow path member 1), 0.8 mm (flow path member 2), and 0.9 mm (flow path member 3)

[0103] Prior to the experiment, the ultrasonic vibration that generates standing waves in the pipe was experimentally determined in advance. Flow path member 1: 980 kHz, Flow path member 2: 1080 kHz, Flow path member 3: 1200 kHz

[0104] Figure 7 is an explanatory diagram showing the method for confirming the effect in Evaluation 1. In Evaluation 1, a glass tube G was connected to the downstream side of the above-mentioned pipe (i.e., the downstream type of the vibrator), and a moving image of the liquid L (fine particles P) flowing in the glass tube G was captured. At that time, together with the image from the front view field A, the image reflected by the mirror M for the 90° side view field B was captured together. (Imaging conditions) Frame rate: 60 Gain: 37 dB

[0105] Figures 8 to 11 are composite photos showing the results of Evaluation 1, and are partial cut-out photos of an image created by superimposing all the frames (600 frames) of a 10-second moving image.

[0106] In the photo, the image that appears white is the polystyrene particles. The more the polystyrene particles converge to the center of the flow path due to acoustic focusing, the clearer the polystyrene particles appear as a white line. Conversely, when the polyester particles are dispersed in the liquid, they are difficult to see in the photo and appear as a blurred image. Therefore, it is possible to determine whether the polystyrene particles are converging or not from each of the photos shown in Figures 8 to 11.

[0107] Figures 8 to 10 are the results when ultrasonic vibrations of a single wavelength that generate standing waves in any of the three flow path members are applied to each flow path member. Figure 8 shows the result of flow path member 1, Figure 9 shows the result of flow path member 2, and Figure 10 shows the result of flow path member 3. In Figures 8 to 10, (a) shows the result of flow path member 1, (b) shows the result of flow path member 2, and (c) shows the result of flow path member 3.

[0108] As shown in FIGS. 8 to 10, when ultrasonic vibration of a single wavelength was applied, it was confirmed that polyester particles were acoustically focused in the flow path member where standing waves were generated by the applied ultrasonic vibration. On the other hand, when ultrasonic vibration not corresponding to the inner diameter of the flow path member was applied, it was confirmed that acoustic focusing did not occur.

[0109] FIG. 11 shows the results when a combined vibration of ultrasonic vibrations that generate standing waves in three flow path members is applied to each of the flow path member 1 (FIG. 11(a)), the flow path member 2 (FIG. 11(b)), and the flow path member 3 (FIG. 11(c)). The combined vibration was created by combining three ultrasonic vibrations of 984 kHz (19 Vpp), 1093 kHz (60 Vpp), and 1202 kHz (61.2 Vpp).

[0110] As shown in FIG. 11, when the combined vibration was applied, it was confirmed that acoustic focusing occurred in all the flow path members.

[0111] (Evaluation 2) In Evaluation 2, the influence of the temperature of the liquid to be processed was confirmed. In Evaluation 2, the flow path member 2 was used, and by changing the temperature of the liquid, the relationship between the temperature of the liquid and the frequency of the ultrasonic vibration that generates standing waves was confirmed.

[0112] FIG. 12 is a photograph showing the results when ultrasonic vibration of a single wavelength is applied to the flow path member. FIG. 12(a) shows the results at a liquid temperature of 20°C and an ultrasonic vibration frequency of 1076 kHz, FIG. 12(b) shows the results at a liquid temperature of 30°C and an ultrasonic vibration frequency of 1076 kHz, and FIG. 12(c) shows the results at a liquid temperature of 30°C and an ultrasonic vibration frequency of 1085 kHz.

[0113] As shown in FIG. 12, in the flow path member 2, appropriate acoustic focusing was confirmed under the conditions of FIG. 12(a). On the other hand, when the liquid temperature was increased while the frequency of the ultrasonic vibration was fixed, acoustic focusing did not progress as shown in FIG. 12(b), and it became difficult to concentrate the particles. Furthermore, when the frequency of the ultrasonic vibration was increased while maintaining the same liquid temperature, appropriate acoustic focusing occurred.

[0114] Therefore, it was confirmed that when the liquid temperature changes, it is possible to appropriately converge sound by changing the frequency of ultrasonic vibration according to the liquid temperature.

[0115] Figure 13 is a photograph showing the result when a composite vibration of ultrasonic vibration with a frequency of 1076 kHz and ultrasonic vibration with a frequency of 1085 kHz is applied to the flow path member. As shown in Figure 13, when the composite vibration was applied to the flow path member, it was possible to appropriately converge sound under both conditions of a liquid temperature of 20°C (Figure 13(a)) and a liquid temperature of 30°C (Figure 13(b)).

[0116] Therefore, when the liquid temperature of the liquid flowing in the fluid device is controlled in the temperature range of 20°C to 30°C, it was confirmed that it is possible to appropriately converge sound by generating a composite vibration of ultrasonic vibration (low-temperature ultrasonic vibration) that generates a standing wave at 20°C (lower limit temperature) and ultrasonic vibration (high-temperature ultrasonic vibration) that generates a standing wave at 30°C (upper limit temperature) in the vibrator.

[0117] (Evaluation 3) In Evaluation 3, the effect when the vibration frequency of the flow path member was changed with time was confirmed. In Evaluation 3, ten flow path members were attached in parallel to the PZT element, and the following liquid was branched at the upstream side and supplied evenly. While supplying the liquid, ultrasonic vibration was applied from the PZT element, and the state of sound convergence was observed. The experimental conditions were as follows. (Conditions) Particles: Fluorescent polystyrene particles (diameter 10 μm) Liquid: Polystyrene particle aqueous dispersion (concentration 1.0×10 4 pieces / mL) Liquid temperature: 25°C Flow rate of liquid: 100 mL / min before branching, 10 mL / min after branching (per flow path member) Vibrator: PZT element (49.5×40 mm, thickness 2 mm, manufactured by Fuji Ceramics Co., Ltd.) Drive voltage: 90 Vpp Pipe: SUS pipe with an inner diameter of 0.8 mm, an outer diameter of 1.59 mm, and a length of 200 mm

[0118] In Evaluation 3, vibrations (1) to (3) below were generated from the oscillator, and the effects were confirmed. (1) Single frequency 1067 kHz (2) Single frequency 1077 kHz (3) Alternately generate two frequencies of 1066 kHz and 1076 kHz for 1 millisecond each

[0119] For each of the respective pipes, a glass tube G was connected to the downstream side of the pipe, and the moving image of the liquid flowing in the pipe was captured by the method shown in FIG. 7. Still images at different imaging times were extracted from the captured moving image, and by overlapping the extracted still images, the trajectories of the fine particles acoustically converged near the center of the glass tube were linearly represented.

[0120] In the evaluation, the width of the trajectory of the fine particles linearly represented was measured as the "convergence width". Evaluation was performed with a convergence width of 181 μm or less, which is required for 10-fold concentration and recovery, being considered as passing, and a convergence width exceeding 181 μm being considered as failing. Note that when the liquid in the pipe forms a laminar flow, it is known that the flow velocity at the center of the laminar flow is about twice the average flow velocity. Since this difference in flow velocity affects the efficiency of fine particle concentration, the above "convergence width required for 10-fold concentration and recovery" is set in consideration of the flow velocity of the liquid together with the cross-sectional area of the pipe (that is, the cross-sectional area of the liquid in the pipe).

[0121] FIGS. 14 and 15 are graphs showing the results of Evaluation 3. FIG. 14 is a graph showing the convergence width in the field of view A in FIG. 7, and FIG. 15 is a graph showing the convergence width in the field of view B in FIG. 7. For the 10 pipes arranged on the PZT element, numbers were assigned from No. 1 to No. 10 from one end side to the other end side, and the numbers are shown on the horizontal axis of the graph. The vertical axis of the graph indicates the convergence width. Also, the passing criterion of "convergence width 181 μm" is shown by a broken line.

[0122] As shown in FIGS. 14 and 15, under the conditions of (1) and (2), the convergence widths of some pipes greatly exceeded the standard. On the other hand, under the condition of (3), except for the field of view A of the No. 8 pipe, the convergence widths of all pipes met the passing criterion, and an obvious improvement was seen.

[0123] From the above results, it was confirmed that the present invention is useful.

Explanation of Reference Numerals

[0124] 1, 2, 3, 21, 25... flow path members, 20A, 20B... converging portions, 22... vibrating portion, 30... control portion, 31... input means, 32... temperature sensor (detection means), 100, 110... fluid devices, 211a, 251a... first flow paths, 212a, 252a... second flow paths, 221... diaphragm, 221a... main surface, 222... vibrator, 331... measurement portion, 332... storage portion, 333... determination portion, 334... signal generation portion, CW... composite waveform, L... liquid, L1... first liquid component, L2... second liquid component, UV1... first ultrasonic vibration, UV2... second ultrasonic vibration, W, W1, W2, W11, W12, W21, W22... standing waves

Claims

1. a converging section having a flow path through which a liquid containing particles flows and converging the particles at a cross section of the flow path while causing the liquid to flow; A control unit that controls an operation of the convergence unit, The converging portion includes a flow path member having a first flow path and a second flow path through which the liquid flows, as the flow path. a vibration unit that vibrates the flow path member, The vibration section includes a vibration plate having a main surface to which the flow path member is attached; a vibrator that vibrates the diaphragm in a thickness direction of the diaphragm, The control unit is a fluid device that causes the transducer to generate a composite vibration of a first ultrasonic vibration having a first frequency and generating a standing wave in the first flow path, and a second ultrasonic vibration having a second frequency and generating a standing wave in the second flow path.

2. The fluidic device according to claim 1 , wherein the control unit causes the transducer to generate ultrasonic vibration having a composite waveform of a vibration waveform of the first ultrasonic vibration and a vibration waveform of the second ultrasonic vibration.

3. The fluidic device according to claim 1 , wherein the control unit changes a frequency of the vibration generated in the oscillator between the first frequency and the second frequency within a unit time.

4. The fluidic device according to claim 1 , wherein the cross section of the first flow path is circular.

5. The cross section of the first flow path is rectangular, A fluid device described in any one of claims 1 to 3, wherein the control unit uses as the first ultrasonic vibration a composite vibration of a first component, which is an ultrasonic vibration whose half wavelength is equal to the length of the long side of the rectangle, and a second component, which is an ultrasonic vibration whose half wavelength is equal to the length of the short side of the rectangle.

6. The control unit includes a storage unit that stores a correspondence relationship between a dimension of the first flow path and the first frequency; An input means for inputting an actual size of the first flow path; A determination unit that determines the first ultrasonic vibration based on the actual size and the correspondence relationship; The fluidic device according to claim 1 , further comprising a signal generating unit that generates a drive signal for causing the oscillator to produce the composite vibration.

7. a detection means for detecting a temperature of the liquid flowing through the first flow path; The control unit includes a measurement unit that determines the temperature from a signal transmitted from the detection unit; a storage unit that stores a correspondence relationship between the temperature and the first frequency; A determination unit that determines the first ultrasonic vibration based on the temperature and the correspondence relationship; The fluidic device according to claim 1 , further comprising a signal generating unit that generates a drive signal for causing the oscillator to produce the composite vibration.

8. the control unit includes a storage unit configured to store a correspondence relationship between an upper limit temperature of a temperature range in which the liquid flowing through the first flow path can change and the first frequency, and a correspondence relationship between a lower limit temperature of the temperature range and the first frequency; A determination unit that determines, as the first ultrasonic vibration, a composite vibration of a high-temperature ultrasonic vibration determined based on a correspondence relationship between the upper limit temperature and the first frequency and a low-temperature ultrasonic vibration determined based on a correspondence relationship between the lower limit temperature and the first frequency; The fluidic device according to claim 1 , further comprising a signal generating unit that generates a drive signal for causing the oscillator to produce the composite vibration.

9. downstream of the vibration unit, the first flow path includes a first branch flow path into which a first liquid component that flows through a center portion of the cross section and in which the particles are concentrated flows; The fluidic device according to claim 1 , further comprising: a second branch flow path into which a second liquid component flowing along a peripheral portion of the cross section flows.

Images