Fluid device

Abstract

To provide a fluid device capable of efficiently recovering a fine particle from fluid.SOLUTION: A fluid device is provided which captures a fine particle included in fluid using supersonic waves. The fluid device incudes: a main body having a flow path in which fluid flows; and an ultrasonic wave application portion which is provided on a flow path wall forming the flow path of the main body and forms a stationary wave by transmitting ultrasonic wave in a Z direction, the main body use as a capture portion, a portion in which an ultrasonic element is disposed, and includes: an inflow portion causing fluid to flow in the capture portion along X direction orthogonal to Z direction; a first outflow portion for flowing concentrated fluid including a fine particle captured by a stationary wave out from the capture portion; and a second outflow portion for flowing dilute fluid having a lower fine particle concentration than that of the concentrated fluid from the capture portion, the inflow portion is provided at a negative side in X direction, of the capture portion, the first outflow portion is provided at a positive side in X direction, of the capture portion, and the second outflow portion is provided at a negative side in X direction, of the capture portion and a position different from the inflow portion.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fluidic device. [Background technology]

[0002] Conventionally, fluidic devices that acoustically focus particles in a fluid are known. For example, a fluidic device disclosed in Non-Patent Document 1 transmits ultrasonic waves from an ultrasonic element into a flow path to form a standing wave. As a result, particles contained in the fluid flowing through the flow path are captured at the node positions of the standing wave due to the pressure gradient of the standing wave. The captured particles are made to flow to one outlet (concentrated fluid outlet) of the flow path, and the diluted fluid is made to flow to the other outlet (diluted fluid outlet). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] E. Benes, and 10 others, “ULTRASONIC SEPARATION OF SUSPENDED PARTICLES”, Reprint Proc. of the 2001 IEEE International Ultrasonics Symposium, a Joint Meeting with the World Congress on Ultrasonics, Atlanta, Georgia, USA, Oct. 7-10, 2001, p649-659. Summary of the Invention [Problem to be solved by the invention]

[0004] However, in a conventional fluid device such as that described in Non-Patent Document 1, a fluid inlet is provided on one side (-X side) of the fluid device, and both a concentrated fluid outlet and a diluted fluid outlet are provided on the other side (+X side). In this case, the fluid flowing into the fluid device from the fluid inlet toward the +X side has a large velocity component not only in the X direction but also in the Z direction perpendicular to the X direction, that is, in the direction in which the ultrasonic element forms a standing wave. Here, when the force due to the velocity component in the Z direction as the force on the particles in the fluid is larger than the force due to the acoustic radiation force of the standing wave, the number of particles captured at the nodes of the standing wave moves against the acoustic radiation force, and the number of particles flowing out from the diluted fluid outlet increases. Therefore, in the conventional fluid device, it is necessary to connect another fluid device to the diluted fluid outlet to form a multi-stage configuration to improve the efficiency of capturing particles, which leads to problems such as high costs and large size of the entire device. [Means for solving the problem]

[0005] A fluidic device of a first aspect of the present disclosure is a fluidic device that captures microparticles contained in a fluid using ultrasound, and comprises a main body having a flow path through which the fluid flows, and an ultrasonic element provided on a flow path wall that forms the flow path of the main body, and transmits ultrasonic waves in a first direction to form a standing wave in the flow path, wherein the main body has an inflow portion that flows the fluid into the capture portion along a second direction intersecting the first direction, with the portion where the ultrasonic element is located as a capture portion, a first outflow portion through which a concentrated fluid containing the microparticles captured by the standing wave flows out of the capture portion, and a second outflow portion through which a diluted fluid having a lower concentration of microparticles than the concentrated fluid flows out of the capture portion, wherein the inflow portion is provided on the negative side of the capture portion in the second direction, the first outflow portion is provided on the positive side of the capture portion in the second direction, and the second outflow portion is provided on the negative side of the capture portion in the second direction at a position different from the inflow portion. [Brief description of the drawings]

[0006] [Figure 1]1 is a cross-sectional view illustrating a fluidic device according to a first embodiment, and the flow of fine particles and a fluid in the fluidic device. [Diagram 2] FIG. 2 is a perspective view showing a main body of the fluidic device according to the first embodiment. [Diagram 3] FIG. 2 is a three-view diagram of the main body of the fluidic device according to the first embodiment. [Figure 4] 4 is a cross-sectional view of the main body taken along line AA in FIG. 3. [Diagram 5] FIG. 2 is a schematic cross-sectional view showing an example of an ultrasonic wave application unit of the first embodiment. [Figure 6] FIG. 4 is a diagram showing the flow velocity and flow direction of a fluid flowing through the fluidic device of the first embodiment. [Figure 7] FIG. 7 is a diagram showing the Z component of flow velocity at each X coordinate position of the line BB in FIG. [Figure 8] FIG. 7 is a diagram showing the X component of flow velocity at each X coordinate position of the line BB in FIG. [Figure 9] 1A and 1B are diagrams showing an outline of a fluidic device of a comparative example and a flow of a fluid; [Figure 10] FIG. 4 is a perspective view showing a fluidic device according to a second embodiment. [Figure 11] FIG. 13 is a perspective view showing a main body of a fluidic device according to a first modified example. [Figure 12] 13 is a diagram showing the distribution of flow velocity and flow direction of a fluid when the fluid is made to flow into the main body of the fluidic device of the first modification. FIG. [Figure 13] 13 is a diagram showing the Z component of flow velocity on an extension in the X direction of an inflow portion of a fluidic device according to the first modification. FIG. [Figure 14] FIG. 11 is a perspective view showing a main body of a fluidic device according to a second modified example. [Figure 15] FIG. 11 is a perspective view showing a main body of a fluidic device according to a second modified example. [Figure 16] FIG. 11 is a perspective view showing a main body of a fluidic device according to a second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007] [First embodiment] The fluidic device of the first embodiment will be described below. (Configuration of Fluid Device) Fig. 1 is a cross-sectional view that illustrates a fluidic device 10 of a first embodiment and the flow of fine particles and a fluid in the fluidic device 10. Fig. 2 is a perspective view that illustrates only a main body 20 of the fluidic device 10, Fig. 3 is a three-view diagram (front view, plan view, and side view) of the main body 20, and Fig. 4 is a cross-sectional diagram of the main body 20 taken along line AA in Fig. 3. The fluidic device 10 includes a block-shaped main body 20, an ultrasonic wave application unit 30 (ultrasonic element) fixed to the main body 20, and a flow path wall unit 40 fixed to the main body 20.

[0008] 2 to 4, the main body 20 includes a central portion 21, a negative side wall portion 22 provided on one side of the central portion 21, and a positive side wall portion 23 provided on the other side of the central portion 21. Here, the direction from the negative side wall portion 22 toward the positive side wall portion 23 is the X direction, the direction intersecting the X direction (perpendicular in this example) is the Z direction, and the direction intersecting the X direction and the Z direction (perpendicular in this example) is the Y direction. In addition, the axis passing through the center point (center of gravity point) when the central portion 21 is cut in the ZY plane and parallel to the X direction is the X axis. Note that the Z direction corresponds to the first direction of this disclosure, the X direction corresponds to the second direction, and the Y direction corresponds to the third direction.

[0009] The central portion 21 of the main body 20 is configured by four bridges 211 connecting the +X side surface of the negative side wall portion 22 and the -X side surface of the positive side wall portion 23. Specifically, the mutually opposing surfaces (surfaces perpendicular to the X-axis) of the negative side wall portion 22 and the positive side wall portion 23 have a substantially rectangular shape, and the four bridges 211 are provided so as to bridge these rectangular corners. These bridges 211, the negative side wall portion 22, and the positive side wall portion 23 form openings 211A at positions opposing each other in the Y direction and at positions opposing each other in the Z direction in the central portion 21. The ultrasonic wave application portion 30 or the flow path wall portion 40 is disposed in each of these openings 211A. For example, in this embodiment, the ultrasonic wave application unit 30 is disposed on the +Z side of the central portion 21 to close the opening 211A on the +Z side, and the flow path wall portion 40 parallel to the ultrasonic wave application unit 30 is disposed on the -Z side of the central portion 21 to close the opening 211A on the -Z side. Also, the flow path wall portion 40 is disposed on each of the openings 211A on the ±Y sides of the central portion 21 to close the opening 211A.

[0010] Furthermore, the negative side wall 22 and the positive side wall 23, which are disposed on either side of the central portion 21 of the main body 20, have wall surfaces perpendicular to the X-axis and face each other. Therefore, the central portion 21 is surrounded by one ultrasonic wave application unit 30, three flow path walls 40, the +X side wall surface of the negative side wall 22, and the -X side wall surface of the positive side wall 23, forming a space whose cross section in the YZ plane is rectangular. This space becomes the capture unit 21S that constitutes a part of the flow path into which the fluid is introduced. Although details will be described later, a standing wave SW (see FIG. 1) is formed by the ultrasonic waves transmitted from the ultrasonic wave application unit 30, and thus fine particles in the fluid flowing through the capture unit 21S are captured. In this embodiment, the flow path wall 40, which is a separate member from the main body 20, is provided at each of the three openings 211A of the main body 20, but the flow path wall 40 may be integrally formed with the main body 20. That is, the openings 211A may not be formed, and a wall corresponding to the flow path wall 40 may be provided in the central portion 21 so as to extend between the bridging portions 211 and continue to the bridging portions 211.

[0011] The ultrasonic wave application unit 30 is not particularly limited as long as it is a device capable of transmitting ultrasonic waves to the capture unit 21S to form a standing wave. For example, it may be a bulk type ultrasonic device that transmits ultrasonic waves by vibrating a piezoelectric body itself, or a thin ultrasonic device (MUT: Micromachined Ultrasonic Transducer) that transmits ultrasonic waves by vibrating a diaphragm. In order to promote miniaturization of the fluid device 10, it is more preferable to use an MUT, and more preferably, a pMUT (Piezoelectric Micromachined Ultrasonic Transducer) that consumes less power for ultrasonic output.

[0012] FIG. 5 is a schematic cross-sectional view showing an example of the ultrasonic wave application unit 30 of the present embodiment. For example, in this embodiment, a pMUT is used as the ultrasound application section 30. Specifically, the ultrasound application section 30 includes a vibration plate 31, a piezoelectric element 32, a suppression section 33, and a reinforcing plate 34, as shown in FIG.

[0013] The diaphragm 31 is composed of a flat first substrate made of, for example, Si, and a flat second substrate made of, for example, a metal oxide such as SiO2 or ZrO2, which is laminated on the +Z side of the first substrate. The -Z side surface of the diaphragm 31 is an ultrasonic transmission surface facing the capture unit 21S. The piezoelectric element 32 is provided on the +Z side (on the second substrate) of the vibration plate 31, and is configured by laminating a first electrode 321, a piezoelectric layer 322, and a second electrode 323 in the Z direction. The piezoelectric layer 322 is configured of a perovskite transition metal oxide containing, for example, Pb, and in this embodiment, is PZT containing Pb, Zr, and Ti.

[0014] The suppression section 33 is a member provided on the +Z side of the vibration plate 31, and is made of, for example, a permanent resist. Specifically, the suppression section 33 is formed in a frame shape surrounding the outer periphery of the piezoelectric element 32 when viewed from the Z direction. The suppression section 33 suppresses the vibration of the vibration plate 31 by connecting the other end opposite to the vibration plate 31 to the reinforcing plate 34. This defines a vibration region (vibration section 311) of the vibration plate 31 that is vibrated by the piezoelectric element 32. That is, in this embodiment, the vibration section 311 of the vibration plate 31 that is surrounded by the suppression section 33 vibrates, and an ultrasonic wave is output. The reinforcing plate 34 has a thickness in the Z direction that is sufficiently larger than that of the vibration plate 31, and is joined to the vibration plate 31 via the suppression section 33, thereby reinforcing the vibration plate 31 and suppressing the suppression section 33 from vibrating together with the vibration plate 31.

[0015] In such an ultrasonic wave applying section 30, by applying a periodic driving voltage between the first electrode 321 and the second electrode 323, the vibration section 311 of the vibration plate 31 vibrates, and ultrasonic waves are transmitted to the -Z side. 5, the vibration plate 31 is partitioned by the suppression section 33 to form the vibration section 311, but the present invention is not limited to this. For example, a separate substrate may be bonded to the -Z side (transmission side of ultrasonic waves) of the vibration plate 31, and an opening window that partitions the vibration section 311 may be formed in the substrate.

[0016] 1 to 4, the flow path wall 40 is a plate-like member that forms the capture section 21S, and is provided at each of the openings 211A on the -Z side and ±Y side of the central section 21 of the main body 20. The material of each flow path wall 40 may be different, but at least the flow path wall 40 disposed at a position opposite the ultrasonic wave application section 30 is made of a material that reflects ultrasonic waves. In this embodiment, the distance L between the ultrasonic wave application unit 30 and the flow path wall unit 40 facing the ultrasonic wave application unit 30 in the Z direction is Z The relationship between the wavelength of the ultrasonic wave and the Z = nλ / 2 (n is an integer equal to or greater than 2). Distance L Z may be appropriately set according to the wavelength λ of the ultrasonic wave that can be output by the ultrasonic wave application unit 30, and the distance L Z The wavelength (frequency) of the ultrasonic wave from the ultrasonic application unit 30 may be adjusted depending on the situation. As described above, the flow path wall portion 40 may be integrally formed with the main body 20.

[0017] In such a configuration, when ultrasonic waves are transmitted from the ultrasonic application section 30 to the fluid in the capture section 21S, a standing wave SW (see Figure 1) is formed between the ultrasonic transmission surface of the ultrasonic application section 30 and the flow path wall section 40 facing the ultrasonic application section 30. 1, the standing wave SW is illustrated at a portion of the X-direction, but in this embodiment, the ultrasonic transmission surface of the ultrasonic application unit 30 is the entire surface on the +Z side of the capture unit 21S, and the standing wave SW is formed in the entire area of ​​the capture unit 21S. Also, in this embodiment, for the sake of simplicity, an example is shown in which a first-order mode standing wave SW is formed by the ultrasonic application unit 30, but a higher-order mode standing wave SW (standing wave SW with multiple node positions) may also be used.

[0018] In the fluidic device 10 of this embodiment, the main body 20 includes an inlet portion 24, a first outlet portion 25, and a second outlet portion 26, which communicate with the capture portion 21S. The inlet portion 24 and the second outlet portion 26 are provided on the negative side wall portion 22 of the main body 20 and communicate with the capture portion 21S. The first outlet portion 25 is provided on the positive side wall portion 23 of the main body 20 and communicates with the capture portion 21S.

[0019] More specifically, the inlet 24 is a fluid inlet for introducing a fluid containing fine particles into the capture unit 21S. In this embodiment, the inlet 24 is formed in the negative side wall 22 so that the center of the inlet 24 coincides with the center of the capture unit 21S when the main body 20 is viewed along the X-axis. That is, in this embodiment, the inlet central axis of the inlet 24, which is provided parallel to the X-direction, coincides with the X-axis. In this embodiment, the cross section of the inlet portion 24 (cross section when cut along the YZ plane) is circular, and the hole diameter W1 thereof is smaller than the hole diameter W2 of the first outlet portion 25 and the hole diameter W3 of the second outlet portion 26. In this embodiment, the inflow section 24 has a flow path extending parallel to the X-axis from the capture section 21S to the -X side end face of the negative side wall section 22, and an inflow tube (not shown) for sending fluid to the fluid device 10 is connected to the inflow connection section 241 (see Figures 3 and 4) at the -X side end.

[0020] The first outlet 25 is provided on the +X side of the capture portion 21S, i.e., on the front side wall portion 23, and communicates with the capture portion 21S. The first outlet 25 is provided at a position facing the inlet 24 across the capture portion 21S, and at a position overlapping with a node of the standing wave SW when viewed from the X direction. For example, in this embodiment, as shown in Fig. 1, a first mode standing wave SW is formed by the ultrasonic wave application unit 30. In this case, there is one node position, which appears at the center of the capture unit 21S in the Z direction. Therefore, the first outlet unit 25 is disposed at a position overlapping with the center of the capture unit 21S and the inlet unit 24 when viewed from the X direction, that is, on the X axis.

[0021] Moreover, the hole diameter W2 of the first outflow section 25 is larger than the hole diameter W1 of the inflow section 24 and smaller than the hole diameter W3 of the second outflow section 26. When the hole diameter W2 of the first outflow section 25 is smaller than the hole diameter W1 of the inflow section 24, the concentrated fluid does not flow out of the first outflow section 25 appropriately, and the fine particle concentration of the fluid flowing out of the second outflow section 26 becomes high. When the hole diameter W2 of the first outflow section 25 is larger than the hole diameter W3 of the second outflow section 26, the amount of fluid flowing out of the first outflow section 25 also increases, and the fine particle concentration of the fluid flowing out of the first outflow section 25 decreases. On the other hand, by making W3>W2>W1 as described above, the fluid containing a large amount of fine particles captured at the node position of the standing wave SW in the capture section 21S, that is, the concentrated fluid with a high fine particle concentration, can be appropriately discharged from the first outflow section 25.

[0022] In this embodiment, the first outflow section 25 has a flow path extending parallel to the X-axis from the capture section 21S to the +X side end face of the positive side wall section 23, and a first outflow tube (not shown) for sending out the concentrated fluid from the fluidic device 10 is connected to a first outflow connection section 251 (see FIGS. 3 and 4) at the +X side end. This makes it possible to recover a concentrated fluid containing a large amount of fine particles (having a high concentration) from the fluidic device 10.

[0023] The second outflow section 26 is provided on the -X side of the capture section 21S, that is, on the negative side wall section 22, and communicates with the capture section 21S. It is preferable that a plurality of second outflow sections 26 are provided, and the second outflow sections 26 are provided at positions symmetrical with respect to the inflow section 24. For example, in this embodiment, two second outflow sections 26 are provided, one of the second outflow sections 26 is located on the +Z side of the inflow section 24, and the other second outflow section 26 is located on the -Z side of the inflow section 24. Thus, the second outflow sections 26 are provided at positions point-symmetrical with respect to the center (X axis) of the inflow section 24. In other words, in the XZ plane passing through the X axis, the pair of second outflow sections 26 are line-symmetrical with respect to the X axis, and in the YZ plane perpendicular to the X axis, the pair of second outflow sections 26 are line-symmetrical with respect to a virtual line passing through the X axis and parallel to the Y direction. In such a configuration, the flow velocity distribution of the fluid on the +Z side and -Z side of the capture section 21S is symmetrical with respect to the X axis. The Z direction is the direction in which the standing wave SW is formed, and the flow velocity distribution is symmetrical on the ±Z side with respect to the X axis, so that no imbalance in the flow velocity Z component occurs. This makes it possible to suppress an increase in the flow velocity Z component.

[0024] As described above, the hole diameter W3 of the second outflow section 26 is larger than the hole diameter W1 of the inflow section 24. If the hole diameter W3 of the second outflow section 26 is smaller than the hole diameter W1 of the inflow section 24, the diluted fluid does not flow out of the second outflow section 26 appropriately, and the flow rate of the first outflow section 25 increases. In this case, the concentration of fine particles in the fluid flowing out of the first outflow section 25 becomes low. If the hole diameter W3 of the second outflow section 26 is smaller than the hole diameter W1 of the inflow section 24, the flow rate in the second outflow section 26 increases, and the flow rate Z component may increase. In contrast, by making W3>W1, the flow rate and flow rate of the fluid flowing out of the second outflow section 26 can be appropriately controlled, and the concentration of the concentrated fluid flowing out of the first outflow section 25 can be increased.

[0025] Furthermore, in this embodiment, the second outflow section 26 has a flow path extending parallel to the X-axis from the capture section 21S to the -X side end face of the negative side wall section 22, and a second outflow tube (not shown) for sending out the diluted fluid from the fluidic device 10 is connected to a second outflow connection section 261 (see FIGS. 3 and 4) at the -X side end. This makes it possible to recover diluted fluid with fewer particles (low concentration) from the fluidic device 10.

[0026] [Relationship between flow rate and particle capture in fluidic devices] Fig. 6 is a diagram showing the flow velocity and flow direction of a fluid flowing through the fluidic device 10 of this embodiment. Fig. 7 is a diagram showing the Z component of the flow velocity at each X coordinate position on the line BB in Fig. 6, and Fig. 8 is a diagram showing the X component of the flow velocity (flow velocity X component) at each X coordinate position on the line BB in Fig. 6. 7 and 8 show simulation data in which the distance L in the X direction of the capture section 21S (the distance from the negative side wall section 22 to the positive side wall section 23) is L = 10 mm, the hole diameter W1 of the inlet section 24 is W1 = 1.2 mm, the hole diameter W2 of the first outlet section 25 is W2 = 1.8 mm, the hole diameter W3 of the second outlet section 26 is W3 = 2.0 mm, the fluid velocity in the inlet section 24 is 0.015 m / s, and the first outlet section 25 and the second outlet section 26 are open to the atmosphere.

[0027] Furthermore, FIG. 9 is a diagram showing the flow rate in the fluidic device of the comparative example. 9, an inlet 92 is provided at the -X and -Z ends of the capture unit 91S, a first outlet 93 (outlet for recovering concentrated fluid) is provided at the +X and -Z ends of the capture unit 91S, and a second outlet 94 (outlet for recovering diluted fluid) is provided at the +X and +Z ends of the capture unit 91S. An ultrasonic wave application unit 95 is provided at the +Z side of the capture unit 91S, and forms a high-order mode standing wave along the Z direction in the capture unit 91S.

[0028] In the fluidic device 10 of this embodiment, the fluid flows from the inlet 24, which has a small pore size, into the capturing section 21S, which has a rapidly increasing pore size. Therefore, when viewed in an XZ cross-sectional view as shown in Fig. 6, the fluid generates vortices on the +Z side and -Z side of the capturing section 21S, and the fluid fills the capturing section 21S.

[0029] More specifically, in this embodiment, only the first outlet 25 along the X-axis is provided in the positive side wall 23, and no other outlets are provided in the positive side wall 23. Meanwhile, in the negative side wall 22, the second outlet 26 is provided on the ±Z side of the inlet 24. In this embodiment, in an XZ cross-sectional view passing through the X-axis, the center of the vortex appears at a position approximately symmetrical with respect to the X-axis at approximately the center in the X-direction of the capture unit 21S. Then, on the +Z side of the capture unit 21S, the fluid flows toward the second outlet 26 provided on the -X side on the +Z side of the vortex center, and on the -Z side of the capture unit 21S, the fluid flows toward the second outlet 26 provided on the -X side on the -Z side of the vortex center. 6, the fluid flowing in from inlet 24 along the X-axis has a dominant flow velocity X component, and the flow velocity Z component is sufficiently smaller than the flow velocity X component. On the -X side of the vortex center, the flow velocity Z component appears, but since it is in the direction toward the X-axis, the fine particles do not flow against the flow toward second outlet 26. On the +X side of the vortex center, the flow velocity Z component appears, but it is sufficiently smaller than the flow velocity X component.

[0030] In this embodiment, the pair of second outlets 26 are arranged side by side in the Z direction with the inlet 24 in between, and are provided at positions that are point symmetrical with respect to the X axis. Therefore, the flow velocity distribution in the region on the +Z side of the X axis and the flow velocity distribution in the region on the -Z side of the X axis are symmetrical, and the power balance between the two is balanced. Therefore, it is possible to suppress the disturbance of the vortex shape due to the difference between the flow velocity distribution on the +Z side and the flow velocity distribution on the -Z side, and the associated increase in the flow velocity Z component.

[0031] Although not shown in the drawings, the fluidic device 10 of this embodiment also generates vortices symmetrical about the X-axis in the XY plane. However, since the second outlet section 26 is not provided on either of the ±Y sides of the inlet section 24, even if the fluid dispersed in the Y direction contains fine particles, the fine particles will not flow out from the second outlet section 26. Moreover, on the +X side of the capture section 21S, the flow velocity Y component is distributed so as to move toward the X axis, so that even if the fluid dispersed in the Y direction contains fine particles, the fine particles will be moved toward the X axis by the flow of the fluid.

[0032] 9, particles can be captured at each node of the standing wave, and many particles are captured at the node on the -Z side where the inlet 92 is located. These particles are swept to the +X side by the flow of the fluid and can be discharged from the first outlet 93. However, in the comparative fluidic device 90, a second outlet 94 is also provided on the +X side of the capture unit 91S. Therefore, as shown in Fig. 9, the fluid flowing toward the second outlet 94 also increases, and a vortex center occurs near the corner of the capture unit 91S on the -X side and +Z side. In this comparative fluidic device 90, in addition to the flow velocity X component from the inlet 92 to the first outlet 93, the flow velocity Z component also increases. That is, in the comparative fluidic device 90, a large flow velocity Z component occurs in the Z direction in which the acoustic radiation force of the standing wave acts, and therefore the number of particles moving in the Z direction against the acoustic radiation force increases.

[0033] Incidentally, whether or not a particle can be efficiently captured at the node position of the standing wave SW is determined by the acoustic radiation force Fs of the standing wave SW and the viscous force Fu of the fluid. The acoustic radiation force Fs is given by the following formula (1), and the fluid viscous force Fu is given by formula (2).

[0034]

number

[0035] Here, V is the volume of the fluid (the volume of the capture section 21S), P is the sound pressure of the ultrasound, ρ0 is the density of the fluid, and c n is the speed of sound in the fluid, k is the ultrasonic wave number (the reciprocal of the ultrasonic wavelength λ), z is the position coordinate in the Z direction, Z is the Z component of the flow velocity, η is the viscosity of the fluid, and a is the diameter of the microparticle. Also, B is B=3(ρ-ρ0) / (2ρ+ρ0), and ρ is the density of the microparticle. The allowable value |Z| of the flow velocity Z component at which the particles do not move in the Z direction with respect to the sound pressure P of the ultrasonic waves applied by the ultrasonic application unit 30 is expressed by the following formula (3).

[0036]

number

[0037] For example, when P = 550 kPa, |Z| is approximately 0.01 m / s, and by making the Z component of the fluid flow velocity less than 0.01 m / s, the particles can be converged to the node position by the acoustic radiation force of the standing wave SW, and movement in the Z direction due to the fluid flow velocity can be suppressed.

[0038] In the comparative example shown in FIG. 9, as described above, the fluid flowing from the inlet 92 into the capture section 91S flows not only toward the first outlet 93 but also toward the second outlet 94, and the flow velocity Z component becomes large. In this case, the flow velocity Z component may exceed 0.01 m / s at a smaller flow rate, and the particles flow in the Z direction against the acoustic radiation force of the standing wave, decreasing the capture efficiency of the particles by the standing wave. For this reason, in order to increase the capture efficiency of the particles, it is necessary to connect another fluid device 90 to the second outlet 94, which increases the size of the device. Alternatively, the drive voltage of the ultrasonic wave application section 95 may be increased to increase the acoustic radiation force, but in this case, an increase in power consumption becomes an issue.

[0039] In contrast, in the present embodiment, as shown in Fig. 7 and Fig. 8, the flow velocity Z component is at most about 0.005 m / s, and it can be confirmed that the flow velocity Z component is less than the allowable value |Z| of the flow velocity Z component at which the particles do not move in the Z direction. In addition, since the flow velocity X component is sufficiently larger than the flow velocity Z component, the particles can be moved to the +X side while being captured at the node position of the standing wave SW. Therefore, in the fluidic device 10 of the present embodiment, a concentrated fluid with a high particle concentration can be discharged from the first outlet 25 with a single fluidic device 10 and with a smaller driving power. 7, the portion where the flow velocity Z component is a negative value is not a problem because the flow is directed toward the X-axis (center). Also, in FIG. 8, the reason why the X-component flow velocity at the position of x=0 is low is because it shows the flow velocity at the boundary position between the inlet portion 24 and the wall surface of the negative side wall portion 22.

[0040] [Effects of this embodiment] The fluid device 10 of this embodiment includes a main body 20 having a flow path through which a fluid flows, and an ultrasonic wave application unit 30 that is provided on a flow path wall that forms the flow path of the main body 20 and transmits ultrasonic waves in the Z direction to form a standing wave SW in the flow path. The main body 20 has a trapping section 21S at a portion where the ultrasonic wave application unit 30 is provided, an inflow section 24 that causes a fluid to flow into the trapping section 21S along the X direction, a first outflow section 25 that causes a concentrated fluid containing a large amount of fine particles captured by the standing wave SW to flow out, and a second outflow section 26 that causes a diluted fluid having a lower concentration of fine particles than the first fluid to flow out from the trapping section 21S. The inflow section 24 is provided on the negative side wall section 22 on the -X side of the trapping section 21S, the first outflow section 25 is provided on the positive side wall section 23 on the +X side of the trapping section 21S, and the second outflow section 26 is provided at a position different from the inflow section 24 on the negative side wall section 22.

[0041] In such a configuration, the fluid flowing into the capture section 21S from the inlet section 24 forms a vortex due to the sudden expansion of the flow path width, and has a flow velocity component not only in the X direction but also in the Z direction. However, in this embodiment, only the first outlet section 25 is provided on the +X side, and the second outlet section 26 is provided on the -X side, so that the flow velocity of the fluid flowing into the capture section 21S from the inlet section 24 at a position along the X axis is dominated by the flow velocity X component toward the first outlet section 25, and the flow velocity Z component is sufficiently small. Therefore, it is possible to suppress the inconvenience of the particles moving in the Z direction against the acoustic radiation force of the standing wave SW. Therefore, for example, it is possible to discharge a concentrated fluid with a high concentration from the first outlet section 25 without connecting multiple fluidic devices 10 or increasing the driving voltage at the ultrasonic wave application section 30.

[0042] In this embodiment, the first outlet section 25 is provided at a position facing the inlet section 24 across the capture section 21S. That is, the inlet section 24 and the first outlet section 25 are each provided along the X-axis. This allows the fluid to flow from the inlet section 24 toward the first outlet section 25 along the X-axis, suppressing an increase in the flow velocity component in the Z direction.

[0043] In this embodiment, the hole diameter W2 of the first outflow portion 25 is larger than the hole diameter W1 of the inflow portion 24. When the aperture diameter W2 of the first outflow portion 25 is smaller than the aperture diameter W1 of the inflow portion 24, the amount of fluid flowing out from the first outflow portion 25 becomes smaller. In this case, there is a possibility that the fine particles that did not flow out from the first outflow portion 25 move in the Z direction and then flow out from the second outflow portion 26. On the other hand, in the present embodiment, since the aperture diameter W2 of the first outflow portion 25 is sufficiently large, by flowing the fine particles captured (converged) at the node position of the standing wave SW as it is in the X-axis direction, a concentrated fluid with a high fine particle concentration can be made to flow out from the first outflow portion 25.

[0044] In the present embodiment, the aperture diameter W3 of the second outflow portion 26 is larger than the aperture diameter W1 of the inflow portion 24. For this reason, the amount of fluid flowing out from the second outflow portion 26 can be increased, and the dilution fluid can be appropriately made to flow out. That is, when the aperture diameter W3 of the second outflow portion 26 is smaller than the aperture diameter W1 of the inflow portion 24, the fluid that cannot flow out from the second outflow portion 26 flows out from the first outflow portion 25, and the concentration of the fine particles in the concentrated fluid decreases. Also, by the flow velocity increasing in the vicinity of the second outflow portion 26, a flow directly from the vicinity of the inflow portion 24 toward the second outflow portion 26 is generated, and the Z-direction component of the flow velocity increases. On the other hand, in the present embodiment, with the above-described configuration, the fluid can be appropriately made to flow out from the second outflow portion 26. Furthermore, the flow velocity in the vicinity of the second outflow portion 26 does not become extremely high, the increase in the Z-direction component of the flow velocity is also suppressed, and the capture efficiency of the fine particles can be improved.

[0045] Also, the aperture diameter W3 of the second outflow portion 26 is larger than the aperture diameter W2 of the first outflow portion 25. When the relationship between the aperture diameter W2 of the first outflow portion 25 and the aperture diameter W3 of the second outflow portion 26 is W2 > W3, the amount of fluid flowing out from the second outflow portion 26 decreases, and the amount of fluid flowing out from the first outflow portion 25 increases. For this reason, the concentration of the fine particles in the concentrated fluid flowing out from the first outflow portion 25 becomes thinner than when W2 < W3. On the other hand, by setting W2 < W3, the inconvenience of the concentration becoming thinner in the concentrated fluid can be suppressed.

[0046] In this embodiment, a pair of second outlet portions 26 are provided, and are provided on the negative side of the capture portion 21S in the X direction, at positions symmetrical with respect to the inlet portion 24. More specifically, the pair of second outlet portions 26 are arranged side by side in the Z direction, and are provided at positions point-symmetrical with respect to the X axis in the YZ plane. This allows the fluid flow to be targeted in the +Z side area and the -Z side area of ​​the capture unit 21S. In other words, the positions of vortices formed by the fluid flow and the flow path distribution are approximately the same, so the flow speed is balanced between the +Z side and the -Z side, and the inconvenience of an increase in the Z direction component of the flow speed can be suppressed.

[0047] In this embodiment, the ultrasonic wave application section 30 forms a standing wave SW whose node position overlaps with the first outlet section 25 when the capture section 21S is viewed along the X direction. That is, in this embodiment, the node position of the standing wave SW is located on the X-axis, and the center of the first outflow portion 25 is located on the X-axis. As described above, in this embodiment, the X-direction component of the flow velocity along the X-axis is large, and the fine particles captured at the node position of the standing wave SW can be pushed out by the flow velocity to the first outflow section 25. This allows a concentrated fluid with a high concentration of fine particles to flow out from the first outflow section 25.

[0048] [Second embodiment] Next, a second embodiment will be described. In the first embodiment, the ultrasonic wave application unit 30 is disposed on the +Z side of the trapping unit 21S to form a standing wave SW in the Z direction. In this case, the acoustic radiation force of the standing wave SW acts so that the particles are converged on the XY plane passing through the X axis, and the particles are suppressed from moving in the Z direction against the acoustic radiation force. On the other hand, the acoustic radiation force does not act in the Y direction. Therefore, if the particles are diffused in the Y direction, the number of particles remaining in the trapping unit 21S increases, and the concentration of the particles flowing out from the first outflow section 25 decreases. Note that, since the X-direction component of the flow velocity along the X axis is sufficiently large, the number of particles diffusing in the Y direction is small, and even if the particles are diffused in the Y direction, the particles move so as to return to the X axis as described in the first embodiment. Therefore, the outflow of the particles from the second outflow section 26 is suppressed. The second embodiment differs from the first embodiment in that a standing wave is also formed in the Y direction.

[0049] FIG. 10 is a perspective view showing a fluidic device 10A of the second embodiment. In FIG. 10, the position of the first outlet portion 25 is hidden by the front side wall portion 23, but similar to the first embodiment, it is provided at a position facing the inlet portion 24 on the X axis and connected to the capture portion 21S. In this embodiment, as shown in FIG. 10, the negative side wall portion 22 is provided with four second outlet portions 26 on the outer periphery of the inlet portion 24. Two of the four second outlet portions 26 are arranged in the Z direction, as in the first embodiment, and are equidistant from the X axis. That is, two of the four second outlet portions 26 are arranged in the Z direction and are provided at positions that are point symmetric with respect to the X axis (inlet portion 24). On the other hand, the other two of the four second outlet portions 26 are arranged in the Y direction and are provided at positions that are point symmetric with respect to the X axis (inlet portion 24). That is, the four second outlet portions 26 are provided rotationally symmetric with respect to the X axis (inlet portion 24).

[0050] Furthermore, in this embodiment, in addition to the ultrasonic wave application unit 30 that forms a standing wave SW in the Z direction, a second ultrasonic wave application unit 30A (second ultrasonic element) that transmits ultrasonic waves along the Y direction and forms a standing wave in the Y direction is provided. This second ultrasonic wave application unit 30A is provided in one of the openings 211A facing each other in the Y direction in the central portion 21 of the main body 20 (the -Y side in FIG. 10). The specific configuration of the second ultrasonic wave application unit 30A is the same as that of the ultrasonic wave application unit 30.

[0051] In such a fluidic device 10A, in the capture section 21S, the particles are converged and captured at the intersection of a node of a standing wave formed in the Z direction and a node of a standing wave formed in the Y direction. When each standing wave is a first-order standing wave, the intersection of the respective nodes coincides with the X-axis, so that the particles are converged and captured along the X-axis. Therefore, in this embodiment, by suppressing the dispersion of the microparticles in the Y direction, the retention of the microparticles in the capture section 21S is suppressed, and it is possible to discharge a concentrated fluid having a higher concentration of microparticles from the first outlet section 25.

[0052] [Effects of this embodiment] The fluidic device 10A of the present embodiment further includes a second ultrasonic wave application unit 30A that transmits ultrasonic waves along the Y direction of the capture unit 21S of the main body 20A and forms standing waves along the Y direction. The second outlets 26 are provided at positions rotationally symmetrical with respect to the inlet 24 on the negative side wall 22 of the capture unit 21S. As a result, in this embodiment, the fine particles contained in the fluid flowing in from the inlet portion 24 can be converged and captured on the X-axis. In other words, the fine particles are not dispersed not only in the Z direction but also in the Y direction, and the fine particles flowing in from the inlet portion 24 can be transported more efficiently to the first outlet portion 25 on the X-axis, and the concentration of fine particles in the concentrated fluid flowing out from the first outlet portion 25 can be increased.

[0053] [Variations] The present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifying, improving, and appropriately combining the embodiments within the scope that can achieve the object of the present invention.

[0054] (Variation 1) In the first and second embodiments, a configuration in which a plurality of second outflow portions 26 are provided has been illustrated, but the present invention is not limited to this. Fig. 11 is a perspective view showing a schematic configuration of a main body 20B of a fluidic device according to Modification 1, Fig. 12 is a diagram showing the distribution of the flow velocity and flow direction of a fluid when the fluid is made to flow into the main body 20B of the fluidic device, and Fig. 13 is a diagram showing the flow velocity Z component on an extension of the inlet portion 24 of the fluidic device in the X direction.

[0055] The main body 20B of the fluidic device according to the first modification includes a central portion 21, a negative side wall portion 22, and a positive side wall portion 23, similar to the first and second embodiments. An ultrasonic wave application portion 30 and a flow path wall portion 40 (not shown) are fixed to the central portion 21 to form a capture portion 21S. Note that the ultrasonic wave application portion 30 and the flow path wall portion 40 are not shown in FIG. 13.

[0056] In the fluid device of the first modification, one second outlet 26 connected to the capture portion 21S is provided on the negative side wall portion 22. Specifically, when the ultrasonic application unit 30 transmits ultrasonic waves in the Z direction to the capture portion 21S to form a standing wave, the second outlet 26 is disposed on the +Z side (or -Z side) of the inlet 24 on the negative side wall portion 22.

[0057] Furthermore, when there is one second outflow portion 26, in terms of the balance of the flow velocity distribution of the fluid flowing through the capture portion 21S, it is preferable that the inflow portion 24 be provided at the end of the negative side wall portion 22 in the Z direction. For example, in the example of Fig. 11, the inflow portion 24 is provided on the -Z side of the negative side wall portion 22. Accordingly, the first outflow portion 25 is located opposite the inflow portion 24 across the capture portion 21S. It is preferable that the first outflow portion 25 be provided at a position on the -Z side of the positive side wall portion 23.

[0058] Furthermore, secondary or higher order standing waves are formed as standing waves formed by the ultrasonic wave application unit 30. In the primary mode standing wave, the node position is the center of the capture unit 21S in the Z direction, and is a position that does not face the first outlet portion 25 (a position offset from the center). In this case, some of the particles captured at the node position of the standing wave may move to the +Z side. In response to this, secondary or higher order standing waves are formed so that at least one node is formed at a position that overlaps with the first outlet portion 25 when viewed from the X direction. This makes it possible to move the fine particles to the +X side by the flow of the fluid and cause them to flow out from the first outflow portion 25, as shown in FIGS.

[0059] In this example, the main body 20B has the inlet 24 at the -Z end of the capture part 21S, the first outlet 25 at the -Z end of the capture part 21S, and the second outlet 26 at the +Z end of the capture part 21S, but the positions of the inlet 24, the first outlet 25, and the second outlet 26 may be moved toward the center in the Z direction of the capture part 21S. However, in this case, the flow path distribution in the capture part 21S, i.e., the distribution of the flow velocity Z component, may become complicated. Therefore, in the case where only one second outlet 26 is provided as in the first modification, it is preferable to provide the inlet 24 and the first outlet 25 at the -Z end and the second outlet 26 at the +Z end.

[0060] In the fluidic device of the first modification, there is only one second outlet portion 26, so the number of tubes connected to the fluidic device can be reduced compared to the first and second embodiments. In other words, when the fluidic device is incorporated into, for example, a particle collection device that collects particles from a fluid, tubes are required to circulate the fluid through the inlet portion 24, the first outlet portion 25, and the second outlet portion 26. Therefore, if the number of tube connections in the particle collection device increases, the configuration becomes more complex and the device becomes larger. In contrast, in the fluidic device of the first modification, the number of second outlet portions 26 is smaller, so the configuration of the particle collection device can be simplified and made smaller.

[0061] (Variation 2) In the first embodiment described above, an example of the main body 20 is shown in Figure 2, but as long as the positions of the inlet portion 24, the first outlet portion 25, and the second outlet portion 26 relative to the capture portion 21S are the same, the flow path shape of the inlet portion 24 and the second outlet portion 26 in the negative side wall portion 22 and the flow path shape of the first outlet portion 25 in the positive side wall portion 23 are not particularly limited. 14 to 16 are perspective views showing examples of main bodies 20C, 20D, and 20E of a fluidic device according to the second modification. 14, second outlet portion 26 on the +Z side extends parallel to the X-axis from capture portion 21S along the -X side in negative side wall portion 22, has a bent portion 262 bent from its tip (-X side end portion) to the +Z side, and further has a flow path shape extending from bent portion 262 to the -X side end face of negative side wall portion 22. Second outlet portion 26 on the -Z side is similar, has a bent portion 262 bent to the -Z side, and further has a flow path shape extending from bent portion 262 to the -X side end face of negative side wall portion 22.

[0062] 15, second outlet portion 26 on the +Z side has, in negative side wall portion 22, an inclined portion 263 that inclines toward the +Z side as it moves away from capture portion 21S, and further has a flow path shape that extends from inclined portion 263 to the -X side end face of negative side wall portion 22. Second outlet portion 26 on the -Z side is similar, and has an inclined portion 263 that inclines toward the -Z side as it moves away from capture portion 21S, and has a flow path shape that extends from inclined portion 263 to the -X side end face of negative side wall portion 22.

[0063] In these main bodies 20C, 20D, the distance between the inlet connection portion 241 corresponding to the inlet portion 24 and the second outlet connection portion 261 can be made longer, thereby reducing the connection work when connecting an inlet tube or a second outlet tube to the main body 20C, 20D.

[0064] 16, second outflow portion 26 on the +Z side is extended from capture portion 21S to the -X side in negative side wall portion 22, and has a folded portion 264 at its tip that is folded toward the +Z side and the +X side, and second outflow portion 26 is extended to the +X side end face of positive side wall portion 23 by folded portion 264. The same is true for second outflow portion 26 on the -Z side, which is extended to the +X side end face of positive side wall portion 23 via folded portion 264. As a result, first outflow connection portion 251 of first outflow portion 25 and second outflow connection portion 261 of second outflow portion 26 are provided on the +X side of main body 20E. Therefore, in a fluidic device using the main body 20E of this example, an inflow tube through which fluid is introduced can be connected to the -X end face, and a first outflow tube and a second outflow tube through which concentrated fluid and diluted fluid flow out can be connected to the +X end face. In other words, the outflow connection ports from which fluid flows out of the fluidic device can be grouped together in the same direction.

[0065] (Variation 3) In the first embodiment, the trapping portion 21S has a rectangular cross section in the YZ plane, but is not limited thereto. For example, the ±Y side flow path wall 40 that is not involved in the formation of standing waves may be curved rather than flat. In addition, the ±Y side flow path wall 40 may be made of a material that has low ultrasonic reflection efficiency or is sound absorbing.

[0066] In the second embodiment, the cross section of the capturing unit 21S in the YZ plane is rectangular to form standing waves in the Y and Z directions, but the cross section may be polygonal, such as a hexagon, and a standing wave may be formed by each combination of a pair of parallel faces that face each other across the capturing unit 21S. For example, when the cross section is hexagonal, standing waves may be formed on each axis that is perpendicular to the X axis and spaced 120 degrees apart.

[0067] (Variation 4) In the first and second embodiments, examples of forming a first-order mode standing wave have been shown, but as described above, a higher-order standing wave may be formed as long as the standing wave has one or more nodes overlapping with a position overlapping with first outflow portion 25 when viewed from the X direction.

[0068] (Modified Example 5) In the first embodiment, an example was shown in which the pore diameters W1, W2, and W3 of the inflow portion 24, the first outflow portion 25, and the second outflow portion 26 satisfy the relationship W1 < W2 < W3, but the present invention is not limited thereto. For example, if the total cross-sectional area of the second outflow portion 26 is larger than that of the first outflow portion 25, W2 = W3 or W2 > W3 may be used.

[0069] [Summary of the Present Disclosure] The fluid device according to the first aspect of the present disclosure is a fluid device that captures fine particles contained in a fluid using ultrasonic waves, and includes a main body having a flow path through which the fluid flows, and an ultrasonic element provided on a flow path wall that forms the flow path of the main body and transmits ultrasonic waves in a first direction to form a standing wave in the flow path. The main body uses a portion where the ultrasonic element is disposed as a capture portion, and includes an inflow portion that allows the fluid to flow into the capture portion along a second direction intersecting the first direction, a first outflow portion through which a concentrated fluid containing the fine particles captured by the standing wave flows out of the capture portion, and a second outflow portion through which a diluted fluid having a lower concentration of the fine particles than the concentrated fluid flows out of the capture portion. The inflow portion is provided on the negative side of the capture portion in the second direction, the first outflow portion is provided on the positive side of the capture portion in the second direction, and the second outflow portion is provided at a position different from the inflow portion on the negative side of the capture portion in the second direction.

[0070] In such a fluid device, the fluid flowing from the inlet into the capture section forms a vortex due to the widening of the flow path width. Therefore, it has a flow velocity component not only in the X direction but also in the Z direction. However, in this embodiment, only the first outlet is provided on the positive side of the second direction, and the second outlet is provided on the negative side. Therefore, on the axis of the inlet, the flow velocity component in the second direction toward the first outlet becomes dominant, and the flow velocity component in the first direction can be sufficiently reduced. Therefore, the inconvenience of the particles moving in the first direction against the acoustic radiation force of the standing wave can be suppressed. Therefore, for example, a concentrated fluid with a high concentration can be discharged from the first outlet without connecting multiple fluid devices or increasing the driving voltage of the ultrasonic element. In other words, a fluid device with high particle capture efficiency can be provided at low cost and in a small size.

[0071] In the fluidic device of this aspect, the first outlet portion is preferably provided at a position facing the inlet portion with the capture portion therebetween. As a result, the fine particles contained in the fluid flowing in from the inlet can be captured at the node of the standing wave formed coaxially with the inlet. Also, as described above, the flow velocity component in the first direction is dominant on the axis of the inlet, so the fine particles captured at the node of the standing wave can be moved to the first outlet by the flow of the fluid, and a highly concentrated fluid can be discharged from the first outlet 25.

[0072] In the fluidic device of this aspect, the hole diameter of the first outlet portion is preferably larger than the hole diameter of the inlet portion. If the pore size of the first outlet is smaller than that of the inlet, the amount of fluid flowing out of the first outlet will be small. In this case, there is a risk that the fine particles that have not flowed out of the first outlet will flow in the first direction and then flow out of the second outlet. In contrast, in this embodiment, the pore size of the first outlet is sufficiently large, so that the fine particles captured at the node position of the standing wave can be directly flowed in the second direction, thereby allowing a concentrated fluid with a high fine particle concentration to flow out of the first outlet.

[0073] In the fluidic device of this aspect, the hole diameter of the second outlet portion is preferably larger than the hole diameter of the inlet portion. If the pore size of the second outlet is smaller than that of the inlet, the fluid that cannot flow out of the second outlet flows out of the first outlet, and the concentration of fine particles in the concentrated fluid decreases. In addition, the flow velocity increases near the second outlet, causing a flow from the inlet to the second outlet directly, and the Z-direction component of the flow velocity increases. In contrast, in this embodiment, the fluid can be appropriately discharged from the second outlet. Furthermore, the flow velocity near the second outlet does not increase significantly, and the increase in the flow velocity component in the first direction is suppressed, improving the efficiency of capturing fine particles.

[0074] In the fluidic device of this aspect, the hole diameter of the second outflow portion is preferably larger than the hole diameter of the first outflow portion. If the pore size of the first outlet 25 is larger than the pore size of the second outlet 26, the amount of fluid flowing out from the second outlet decreases and the amount of fluid flowing out from the first outlet increases. Therefore, the concentration of fine particles in the concentrated fluid flowing out from the first outlet decreases. In contrast, in this embodiment, the decrease in the concentration of the concentrated fluid can be suppressed.

[0075] In the fluidic device of this aspect, the inflow portion is preferably provided in the center of the capture portion when the capture portion is viewed along the second direction. As a result, the flow velocity distribution of the fluid flowing in from the inlet becomes symmetrical with respect to the axis of the inlet (the axis parallel to the second direction). Therefore, the balance of the stress acting on the particles due to the flow velocity is balanced, and the increase in the flow velocity component in the first direction can be suppressed.

[0076] In the fluidic device of this aspect, it is preferable that a plurality of the second outflow portions are provided, and are provided at positions symmetrical with respect to the inflow portion on the negative side of the capture portion in the second direction. As a result, similar to the above-described embodiment, the flow velocity distribution of the fluid flowing in from the inlet can be made symmetrical with respect to the axis of the inlet (axis parallel to the second direction), the balance of the stress acting on the microparticles due to the flow velocity can be balanced, and an increase in the flow velocity component in the first direction can be suppressed.

[0077] In the fluidic device of this aspect, the second outlet portions are provided at positions that are point-symmetric with respect to the center of the inlet portion along the first direction. In this embodiment, the second outlet is point-symmetrical along the first direction in which the ultrasonic wave application unit forms a standing wave, so that the flow velocity distribution of the fluid in the first direction can be made symmetrical with respect to the axis of the inlet (axis parallel to the second direction), and an increase in the flow velocity component in the first direction can be suppressed.

[0078] In the fluid device of this embodiment, a second ultrasonic element is provided on the flow path wall forming the flow path of the main body, transmits ultrasonic waves along a third direction perpendicular to the first direction and the second direction of the capture portion, and forms a standing wave along the third direction, and the second outflow portion is provided on the negative side of the capture portion at a position that is rotationally symmetrical with respect to the inflow portion. In this embodiment, by forming standing waves along the first and third directions, the nodes of these standing waves overlap, and the particles can be captured at the central axis of the capture section, i.e., the axis of the inlet section. Therefore, even if a second outlet section is provided between the inlet section and the first direction, not only at a position along the first direction of the inlet section but also at a position along the third direction of the inlet section, the movement of the particles in the first and third directions is restricted. This allows a concentrated fluid with a higher concentration to flow out from the first outlet section.

[0079] In the fluid device of this aspect, it is preferable that the ultrasonic element forms a standing wave whose node position overlaps with the first outlet portion when the capture portion is viewed along the second direction. In this embodiment, the flow velocity component along the second direction is large, and the fine particles captured at the node position of the standing wave can be pushed and discharged into the first outlet by the flow velocity, thereby allowing a concentrated fluid having a high concentration of fine particles to flow out from the first outlet. [Explanation of symbols]

[0080] 10,10A...Fluid device, 20,20A,20B,20C,20D,20E...Body, 21...Central part, 21S...Catching part, 22...Negative side wall part, 23...Positive Side wall section, 24...Inflow section, 25...First outflow section, 26...Second outflow section, 30...Ultrasonic application section, 30A...Second ultrasonic application section, 40...Channel wall section, SW...Standing wave.

Claims

1. A fluidic device that captures particles contained in a fluid using ultrasound, A body having a flow path through which the fluid flows; an ultrasonic element provided in a flow path wall that forms the flow path of the main body, the ultrasonic element transmitting an ultrasonic wave in a first direction to form a standing wave in the flow path; The main body has a capturing portion in which the ultrasonic element is disposed, an inlet portion that allows the fluid to flow into the capture portion along a second direction intersecting the first direction; a first outlet through which a concentrated fluid containing the fine particles captured by the standing wave flows out from the capture section; a second outlet through which a dilute fluid having a lower concentration of the particles than the concentrated fluid flows out from the capture section; The inflow portion is provided on the negative side of the capture portion in the second direction, The first outlet portion is provided on the positive side of the capture portion in the second direction, A fluidic device, wherein the second outlet portion is provided at a position different from the inlet portion on the negative side of the capture portion in the second direction.

2. The first outlet portion is provided at a position facing the inlet portion across the capture portion. The fluidic device according to claim 1 .

3. The hole diameter of the first outlet portion is larger than the hole diameter of the inlet portion. The fluidic device according to claim 1 .

4. The hole diameter of the second outlet portion is larger than the hole diameter of the inlet portion. The fluidic device according to claim 1 .

5. The hole diameter of the second outlet portion is larger than the hole diameter of the first outlet portion. The fluidic device according to claim 1 .

6. The inlet portion is provided at the center of the capture portion when the capture portion is viewed along the second direction. The fluidic device according to claim 1 .

7. The second outflow portion is provided in plurality, and is provided at a position symmetrical with respect to the inflow portion on the negative side of the capture portion in the second direction. The fluidic device according to claim 1 .

8. The second outflow portions are provided at positions that are point symmetrical with respect to a center of the inflow portion along the first direction, The fluidic device according to claim 7 .

9. a second ultrasonic element provided in the flow path wall that forms the flow path of the main body, transmitting ultrasonic waves along a third direction perpendicular to the first direction and the second direction of the capture portion, and forming a standing wave along the third direction; The second outflow portion is provided at a position rotationally symmetrical with respect to the inflow portion on the negative side of the capture portion, The fluidic device according to claim 7 .

10. The ultrasonic element forms the standing wave whose node position overlaps with the first outflow portion when the capture portion is viewed along the second direction. The fluidic device according to claim 1 .

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