Fluid device

Abstract

The present invention provides a fluid device capable of efficiently collecting fine particles from a fluid. The fluid device captures particles contained in a fluid using ultrasonic waves, and is provided with: a main body having a flow path through which the fluid flows; and an ultrasonic wave applying unit that is provided on a flow path wall that forms a flow path of the main body and that transmits ultrasonic waves in the Z direction to form standing waves, the main body having a portion in which the ultrasonic element is disposed as a capture unit, the main body having: an inflow unit that causes a fluid to flow into the capture unit in an X direction that intersects the Z direction; a first outflow unit that causes a concentrated fluid containing the particles captured by the standing waves to flow out from the capturing unit; and a second outflow part that causes a diluted fluid having a lower concentration of particles than the concentrated fluid to flow out from the capturing part, the inflow part being provided on the negative side of the capturing part in the X direction, the first outflow part being provided on the positive side of the capturing part in the X direction, and the second outflow part being provided on the negative side of the capturing part in the X direction at a position different from the inflow part.

Description

Technical Field

[0001] The present invention relates to fluid devices. Background Art

[0002] At present, there are known fluid devices that acoustically gather particles in a fluid. For example, the fluid device disclosed in non-patent document 1 sends ultrasonic waves from an ultrasonic element into a flow channel to form standing waves. As a result, particles contained in the fluid flowing in the flow channel are captured at the node position of the standing wave by the pressure gradient of the standing wave. The captured particles flow to one outlet of the flow channel (the concentrated fluid outlet), and the diluted fluid flows to the other outlet (the diluted fluid outlet).

[0003] Non-patent document 1: E. Benes et al., "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

[0004] However, in an existing fluid device such as 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 dilute 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 not only increases in velocity component relative to the X direction, but also increases in velocity component relative to the Z direction orthogonal to the X direction, that is, the direction in which the standing wave is formed by the ultrasonic element. Here, in the case where the force involved in the particles in the fluid, caused by the velocity component relative to the Z direction, is greater than the force caused by the acoustic radiation force of the standing wave, the particles captured at the nodes of the standing wave overcome the acoustic radiation force and move, and the number of particles flowing out of the dilute fluid outlet increases. Therefore, in the existing fluid device, it is necessary to further connect the fluid device to the dilute fluid outlet to form a multi-stage structure to improve the capture efficiency of the particles. Accordingly, there are technical problems of increased cost and larger device as a whole. Summary of the invention

[0005] A first mode of the fluid device disclosed herein uses ultrasound to capture particles contained in a fluid, and comprises: a main body having a flow channel for the fluid to flow; and an ultrasonic element, which is arranged on a flow channel wall of the flow channel forming the main body and transmits ultrasound in a first direction to form a standing wave in the flow channel, wherein the main body is provided with a portion of the ultrasonic element as a capturing portion, and comprises: an inflow portion, which allows the fluid to flow into the capturing portion along a second direction intersecting the first direction; a first outflow portion, which allows a concentrated fluid containing the particles captured by the standing wave to flow out of the capturing portion; and a second outflow portion, which allows a diluted fluid having a lower concentration of the particles than the concentrated fluid to flow out of the capturing portion, wherein the inflow portion is arranged on the negative side of the second direction of the capturing portion, the first outflow portion is arranged on the positive side of the second direction of the capturing portion, and the second outflow portion is arranged on the negative side of the second direction of the capturing portion at a position different from the inflow portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 1 is a cross-sectional view schematically showing the fluid device according to the first embodiment and the flow of particles and fluid in the fluid device.

[0007] Figure 2 It is a perspective view showing the main body of the fluid device according to the first embodiment.

[0008] Figure 3 3D are three-view diagrams of the main body of the fluid device according to the first embodiment.

[0009] Figure 4 is along Figure 3 A cross-sectional view of the main body when cut along line AA.

[0010] Figure 5 This is a schematic cross-sectional view showing an example of the ultrasonic applying unit according to the first embodiment.

[0011] Figure 6 It is a diagram showing the flow velocity and flow direction of the fluid flowing in the fluid device according to the first embodiment.

[0012] Figure 7 It is shown Figure 6 A graph of the Z component of flow velocity at each X coordinate position of line BB.

[0013] Figure 8 It is shown Figure 6 A graph of the X-component of the flow velocity at each X-coordinate position of the BB line.

[0014] Fig. 9 1 is a diagram showing a schematic diagram of a fluid device according to a comparative example and the flow of a fluid.

[0015] Fig.10It is a perspective view showing a fluid device according to a second embodiment.

[0016] Fig.11 It is a perspective view showing a main body of a fluid device according to Modification 1.

[0017] Fig.12 This is a diagram showing the distribution of the flow velocity and flow direction of the fluid when the fluid is allowed to flow into the main body of the fluid device according to Modification 1.

[0018] Fig.13 1 is a diagram showing a flow velocity Z component in an extension of an inflow portion of a fluid device according to Modification 1 in the X direction.

[0019] Fig.14 It is a perspective view showing a main body of a fluid device according to Modification 2.

[0020] Fig.15 It is a perspective view showing a main body of a fluid device according to Modification 2.

[0021] Fig.16 It is a perspective view showing a main body of a fluid device according to Modification 2.

[0022] Description of Reference Numerals

[0023] 10, 10A: fluid device; 20, 20A, 20B, 20C, 20D, 20E: main body; 21: central part; 21S: capturing part; 22: negative side wall part; 23: positive side wall part; 24: inflow part; 25: first outflow part; 26: second outflow part; 30: ultrasonic wave applying part; 30A: second ultrasonic wave applying part; 40: flow channel wall part; SW: standing wave. DETAILED DESCRIPTION

[0024] First embodiment

[0025] Hereinafter, a fluid device according to a first embodiment will be described.

[0026] Composition of fluid device

[0027] Figure 1 1 is a cross-sectional view schematically showing the fluid device 10 according to the first embodiment and the flow of particles and fluid in the fluid device 10 . Figure 2 is a perspective view showing only the main body 20 of the fluid device 10, Figure 3 It is the three views (front view, top view, side view) of the main body 20. Figure 4 is along Figure 3 A cross-sectional view of the main body 20 when cut along line AA.

[0028] The fluid device 10 includes a block-shaped main body 20 , an ultrasonic wave applying unit 30 (ultrasonic wave element) fixed to the main body 20 , and a flow path wall 40 fixed to the main body 20 .

[0029] like Figures 2 to 4 As shown, 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 set as the X direction, the direction intersecting the X direction (orthogonal in this example) is set as the Z direction, and the direction intersecting the X direction and the Z direction (orthogonal in this example) is set as the Y direction. In addition, the axis passing through the center point (center of gravity) when the central portion 21 is cut by the ZY plane and parallel to the X direction is set as the X axis. In addition, the Z direction is equivalent to the first direction of the present disclosure, the X direction is equivalent to the second direction, and the Y direction is equivalent to the third direction.

[0030] The central portion 21 of the main body 20 is composed of four cross-linked portions 211 connecting the surface of the negative side wall portion 22 on the +X side and the surface of the positive side wall portion 23 on the -X side. Specifically, the mutually opposing surfaces (surfaces orthogonal to the X-axis) of the negative side wall portion 22 and the positive side wall portion 23 have a substantially rectangular shape, and four cross-linked portions 211 are provided in a manner of cross-linking these rectangular corners. Openings 211A are formed at positions opposing in the Y direction and positions opposing in the Z direction in the central portion 21 by these cross-linked portions 211, the negative side wall portion 22, and the positive side wall portion 23. The ultrasonic applying portion 30 or the flow channel wall portion 40 is respectively arranged in these openings 211A. For example, in the present embodiment, the ultrasonic wave applying 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 channel wall 40 parallel to the ultrasonic wave applying unit 30 is disposed on the -Z side of the central portion 21 to close the opening 211A on the -Z side. In addition, the flow channel wall 40 is disposed in each of the openings 211A on the ±Y sides of the central portion 21 to close the openings 211A.

[0031] Furthermore, the negative side wall portion 22 and the positive side wall portion 23 arranged across the central portion 21 of the main body 20 have wall surfaces orthogonal to the X-axis and are opposed to each other. Therefore, the central portion 21 is surrounded by an ultrasonic applying portion 30, three flow channel walls 40, the wall surface on the +X side of the negative side wall portion 22, and the wall surface on the -X side of the positive side wall portion 23, thereby forming a rectangular space in a cross-sectional view on the YZ plane. This space becomes a capture portion 21S constituting a part of the flow channel for the introduced fluid. By utilizing the ultrasonic wave emitted from the ultrasonic applying portion 30 to form a standing wave SW (refer to Figure 1 ) to capture particles in the fluid flowing in the capture section 21S, as will be described in detail later.

[0032] In addition, in the present embodiment, the flow path wall portion 40 is provided as a separate member from the main body 20 at the three openings 211A of the main body 20, but the flow path wall portion 40 may be formed integrally with the main body 20. That is, it is also possible to form a structure in which a wall corresponding to the flow path wall portion 40 is provided between the central portion 21 and the cross-linked portion 211 continuously with the cross-linked portion 211 without forming the openings 211A.

[0033] The ultrasonic applying unit 30 is not particularly limited as long as it is a device that can send ultrasonic waves to the capturing unit 21S to form standing waves. For example, it can be a block-type ultrasonic device that sends ultrasonic waves by vibrating the piezoelectric body itself, or it can be a thin ultrasonic device (MUT: Micromachined Ultrasonic Transducer) that sends ultrasonic waves by vibrating a vibration plate. In order to promote the miniaturization of the fluid device 10, it is more preferable to use an MUT, and more preferably a pMUT (Piezoelectric Micromachined Ultrasonic Transducer) with low power consumption involved in the output of ultrasonic waves.

[0034] Figure 5 It is a schematic cross-sectional view showing an example of the ultrasonic wave applying unit 30 according to the present embodiment.

[0035] For example, in this embodiment, a pMUT is used as the ultrasonic applying unit 30. Specifically, Figure 5 As shown, the ultrasonic wave applying unit 30 includes a vibration plate 31 , a piezoelectric element 32 , a suppressing unit 33 , and a reinforcing plate 34 .

[0036] The vibration plate 31 is composed of a flat first substrate and a flat second substrate. The first substrate is formed of, for example, Si, and the second substrate is laminated on the +Z side of the first substrate and is formed of, for example, SiO. 2 or ZrO 2 The surface on the -Z side of the vibration plate 31 serves as an ultrasonic wave transmitting surface facing the capturing portion 21S.

[0037] The piezoelectric element 32 is provided on the +Z side (on the second substrate) of the vibration plate 31, and is formed by stacking a first electrode 321, a piezoelectric layer 322, and a second electrode 323 in the Z direction. The piezoelectric layer 322 is composed of, for example, a perovskite-type transition metal oxide containing Pb, and in this embodiment, is PZT containing Pb, Zr, and Ti.

[0038] The suppression part 33 is a component provided on the +Z side of the vibration plate 31, and is composed of, for example, a permanent resist or the like. Specifically, the suppression part 33 is formed in a frame shape that surrounds the outer periphery of the piezoelectric element 32 when viewed from the Z direction. The suppression part 33 suppresses the vibration of the vibration plate 31 by connecting the other end on the opposite side of the vibration plate 31 to the reinforcing plate 34. Thus, the vibration area (vibration part 311) of the vibration plate 31 that is vibrated by the piezoelectric element 32 is defined. That is, in the present embodiment, the vibration part 311 surrounded by the suppression part 33 in the vibration plate 31 vibrates to output ultrasonic waves.

[0039] The reinforcing plate 34 has a sufficiently larger thickness in the Z direction than the vibration plate 31 , is bonded to the vibration plate 31 via the restraining portion 33 to reinforce the vibration plate 31 , and restrains the restraining portion 33 from vibrating together with the vibration plate 31 .

[0040] In such an ultrasonic wave applying unit 30 , by applying a periodic driving voltage between the first electrode 321 and the second electrode 323 , the vibration unit 311 of the vibration plate 31 vibrates, and ultrasonic waves are transmitted toward the −Z side.

[0041] also, Figure 5 The example is an example of forming the vibration part 311 by dividing the vibration plate 31 by the suppression part 33, but it is not limited to this. For example, a substrate may be bonded to the -Z side (ultrasonic wave transmission side) of the vibration plate 31, and an opening window for dividing the vibration part 311 may be formed on the substrate.

[0042] return Figures 1 to 4 The flow channel wall 40 is a plate-shaped member forming the capture portion 21S, and is respectively provided at the openings 211A on the -Z side and the ±Y side of the central portion 21 of the main body 20. The materials of each flow channel wall 40 may be different, but at least the flow channel wall 40 disposed at a position opposite to the ultrasonic applying portion 30 is formed of a material that reflects ultrasonic waves.

[0043] In the present embodiment, the distance L between the ultrasonic wave applying unit 30 and the flow path wall 40 facing the ultrasonic wave applying unit 30 in the Z direction is Z The relationship between the wavelength λ of the ultrasonic wave is L Z =nλ / 2 (n is an integer greater than or equal to 2). The distance L can be appropriately set according to the wavelength λ of the ultrasonic wave that can be output by the ultrasonic wave applying unit 30. Z , or according to the distance L Z The wavelength (frequency) of the ultrasonic wave of the ultrasonic wave applying unit 30 is adjusted.

[0044] In addition, as described above, the flow channel wall portion 40 may be formed integrally with the main body 20 .

[0045] In such a configuration, when ultrasonic waves are transmitted from the ultrasonic wave applying section 30 to the fluid in the capturing section 21S, a standing wave SW is formed between the ultrasonic wave transmitting surface of the ultrasonic wave applying section 30 and the flow channel wall section 40 facing the ultrasonic wave applying section 30 (see FIG. Figure 1 ).

[0046] In addition, Figure 1 In the figure, the standing wave SW is illustrated at a part of the position in the X direction, but in the present embodiment, the ultrasonic wave transmitting surface of the ultrasonic wave applying unit 30 is the entire surface on the +Z side of the capturing unit 21S, and the standing wave SW is formed in the entire area of ​​the capturing unit 21S. In addition, in the present embodiment, in order to simplify the description, an example of forming a standing wave SW of a first-order mode by the ultrasonic wave applying unit 30 is shown, but it may also be a standing wave SW of a higher-order mode (a standing wave SW having a plurality of nodes).

[0047] Furthermore, in the fluid device 10 of the present embodiment, the main body 20 includes the inflow portion 24 communicating with the capture portion 21S, the first outflow portion 25 , and the second outflow portion 26 .

[0048] The inflow portion 24 and the second outflow 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 outflow portion 25 is provided on the positive side wall portion 23 of the main body 20 and communicates with the capture portion 21S.

[0049] More specifically, the inflow portion 24 is an inlet for introducing a fluid containing microparticles into the capture portion 21S. In the present embodiment, when the main body 20 is viewed along the X-axis, the inflow portion 24 is formed on the negative side wall portion 22 in such a manner that the center of the inflow portion 24 coincides with the center of the capture portion 21S. That is, in the present embodiment, the inflow center axis of the inflow portion 24 provided parallel to the X-direction coincides with the X-axis.

[0050] In the present embodiment, the inflow portion 24 has a circular cross section (a cross section cut along the YZ plane) and a hole diameter W1 thereof is smaller than the hole diameter W2 of the first outflow portion 25 and the hole diameter W3 of the second outflow portion 26 .

[0051] In this embodiment, the inlet portion 24 has a flow path extending from the capture portion 21S to the -X side end surface of the negative side wall portion 22 in parallel with the X axis, and an inlet connection portion 241 (see Figure 3 , Figure 4 ) is connected to an inlet pipe (not shown) for conveying fluid to the fluid device 10.

[0052] The first outflow portion 25 is provided on the +X side of the capture portion 21S, that is, the positive side wall portion 23, and communicates with the capture portion 21S. The first outflow portion 25 is provided at a position opposite to the inflow portion 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.

[0053] For example, in this embodiment, Figure 1 As shown, a standing wave SW of the first-order mode is formed by the ultrasonic applying unit 30. In this case, there is only one node, which appears at the center of the capture unit 21S in the Z direction. Therefore, when viewed from the X direction, the first outflow portion 25 is arranged at a position overlapping with the center of the capture unit 21S or the inflow portion 24, that is, on the X axis.

[0054] In addition, the aperture W2 of the first outflow portion 25 is larger than the aperture W1 of the inflow portion 24, and smaller than the aperture W3 of the second outflow portion 26. When the aperture W2 of the first outflow portion 25 is smaller than the aperture W1 of the inflow portion 24, the concentrated fluid does not properly flow out from the first outflow portion 25, and the particle concentration of the fluid flowing out from the second outflow portion 26 becomes high. In addition, when the aperture W2 of the first outflow portion 25 is larger than the aperture W3 of the second outflow portion 26, the amount of fluid flowing out from the first outflow portion 25 also increases, and the particle concentration of the fluid flowing out from the first outflow portion 25 decreases. In contrast, by setting W3>W2>W1 as described above, the fluid containing many particles captured at the node position of the standing wave SW in the capturing portion 21S, that is, the concentrated fluid with a high particle concentration can be appropriately flowed out from the first outflow portion 25.

[0055] In this embodiment, the first outflow portion 25 has a flow path extending from the capture portion 21S to the +X side end surface of the positive side wall portion 23 in parallel with the X axis, and a first outflow connection portion 251 (see Figure 3 , Figure 4 ) is connected to a first outflow pipe (not shown) for sending the concentrated fluid out of the fluid device 10. Thus, the concentrated fluid containing many particles (high concentration) can be recovered from the fluid device 10.

[0056] The second outflow portion 26 is disposed on the -X side of the capture portion 21S, that is, the negative side wall portion 22, and is connected to the capture portion 21S. The second outflow portion 26 is provided in plurality, and is preferably provided at a position symmetrical with respect to the inflow portion 24. For example, in the present embodiment, two second outflow portions 26 are provided, one second outflow portion 26 is located on the +Z side of the inflow portion 24, and the other second outflow portion 26 is located on the -Z side of the inflow portion 24. Therefore, it is provided at a position that is point-symmetrical with respect to the center (X-axis) of the inflow portion 24. In other words, in the XZ plane passing through the X-axis, a pair of second outflow portions 26 are linearly symmetrical with respect to the X-axis, and in the YZ plane orthogonal to the X-axis, a pair of second outflow portions 26 are linearly 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 is symmetrical with respect to the X-axis on the +Z side and -Z side of the capture portion 21S. The Z direction is the direction in which the standing wave SW is formed, and by making the flow velocity distribution symmetrical on the ±Z sides with respect to the X axis, there is no imbalance in the flow velocity Z component. This can suppress an increase in the flow velocity Z component.

[0057] In addition, as described above, the aperture W3 of the second outflow portion 26 is larger than the aperture W1 of the inflow portion 24. When the aperture W3 of the second outflow portion 26 is smaller than the aperture W1 of the inflow portion 24, the dilution fluid does not properly flow out from the second outflow portion 26, and the flow rate of the first outflow portion 25 increases. In this case, the particle concentration of the fluid flowing out of the first outflow portion 25 becomes lower. In addition, when the aperture W3 of the second outflow portion 26 is smaller than the aperture W1 of the inflow portion 24, the flow velocity in the second outflow portion 26 increases, and the flow velocity Z component may also increase. In contrast, by setting W3>W1, the flow rate and flow velocity of the fluid flowing out of the second outflow portion 26 can be properly controlled, and the concentration of the concentrated fluid flowing out of the first outflow portion 25 can be increased.

[0058] Furthermore, in this embodiment, the second outflow portion 26 has a flow channel extending from the capture portion 21S to the -X side end surface of the negative side wall portion 22 in parallel with the X axis, and a second outflow connection portion 261 (see Figure 3 , Figure 4 ) is connected to a second outflow pipe (not shown) for sending the dilution fluid out of the fluid device 10. Thus, the dilution fluid with less particles (low concentration) can be recovered from the fluid device 10.

[0059] Relationship between flow rate and particle capture in fluid devices

[0060] Figure 6 1 is a diagram showing the flow velocity and flow direction of the fluid flowing in the fluid device 10 according to the present embodiment. Figure 7 It is shown Figure 6 A graph of the Z component of the flow velocity at each X coordinate position on the BB line, Figure 8 It is shown Figure 6 FIG. 5 is a graph of the X component of the flow velocity (flow velocity X component) at each X coordinate position on the BB line.

[0061] also, Figure 7 and Figure 8 It is simulation data when the distance L in the X direction of the capture portion 21S (the distance from the negative side wall portion 22 to the positive side wall portion 23) is set to L=10 mm, the aperture W1 of the inlet portion 24 is set to W1=1.2 mm, the aperture W2 of the first outflow portion 25 is set to W2=1.8 mm, the aperture W3 of the second outflow portion 26 is set to W3=2.0 mm, the velocity of the fluid in the inflow portion 24 is set to 0.015 m / s, and the first outflow portion 25 and the second outflow portion 26 are opened to the atmosphere.

[0062] and then, Fig. 9 It is a graph showing the flow velocity in the fluid device of the comparative example.

[0063] exist Fig. 9 In the fluid device 90 of the comparative example, an inflow portion 92 is provided at the -X side and -Z side end of the capture portion 91S, a first outflow portion 93 (an outflow portion for recovering concentrated fluid) is provided at the +X side and -Z side end of the capture portion 91S, and a second outflow portion 94 (an outflow portion for recovering diluted fluid) is provided at the +X side and +Z side end of the capture portion 91S. In addition, an ultrasonic wave applying portion 95 is provided at the +Z side of the capture portion 91S, and a standing wave of a high-order mode along the Z direction is formed in the capture portion 91S.

[0064] In the fluid device 10 of this embodiment, the fluid flows from the inlet 24 with a small pore size into the capture part 21S with a rapidly increasing pore size. Figure 6 When the XZ cross section is observed as shown, the fluid generates vortices on the +Z side and the -Z side of the capturing portion 21S, and the capturing portion 21S is filled with the fluid.

[0065] More specifically, in the present embodiment, only the first outflow portion 25 along the X-axis is provided in the positive side wall portion 23, and no other outflow ports are provided in the positive side wall portion 23. On the other hand, in the negative side wall portion 22, second outflow portions 26 are provided on the ±Z sides of the inflow portion 24, respectively. In such the present embodiment, in the XZ cross-section observation through the X-axis, the center of the vortex appears at a position approximately symmetrical with respect to the X-axis in the approximate center of the X direction of the capture portion 21S. Moreover, on the +Z side of the capture portion 21S, at a position closer to the +Z side than the center of the vortex, and on the -Z side of the capture portion 21S, at a position closer to the -Z side than the center of the vortex, the fluid flows in a manner toward the second outflow portion 26 provided on the -X side.

[0066] As a result, if Figure 6As shown, the flow velocity X component of the fluid flowing in from the inflow portion 24 along the X axis becomes dominant, and the flow velocity Z component becomes sufficiently smaller than the flow velocity X component. The flow velocity Z component appears at a position closer to the -X side than the center of the vortex, but it is in the direction of the X axis, so the particles do not flow back to the second outflow portion 26. At a position closer to the +X side than the center of the vortex, the flow velocity Z component appears, but it is sufficiently smaller than the flow velocity X component.

[0067] In addition, in the present embodiment, a pair of second outflow portions 26 are arranged in the Z direction across the inflow portion 24, and are respectively arranged at positions that are point-symmetrical with respect to the X-axis. Therefore, the flow velocity distribution of the region closer to the +Z side than the X-axis and the flow velocity distribution of the region closer to the -Z side than the X-axis become symmetrical shapes, and the two achieve dynamic balance. Therefore, the disturbance of the vortex shape caused by the difference between the flow velocity distribution on the +Z side and the flow velocity distribution on the -Z side and the increase of the flow velocity Z component accompanying this can be suppressed.

[0068] Although not shown in the drawings, the fluid device 10 of the present embodiment also generates vortices that are symmetrical about the X-axis in the XY plane.

[0069] However, since the second outflow portion 26 is not provided on the ±Y sides of the inflow portion 24, even if the fluid dispersed in the Y direction contains particles, the particles do not flow out from the second outflow portion 26. In addition, on the +X side of the capture portion 21S, the flow velocity Y component is distributed toward the X axis, so even if the fluid dispersed in the Y direction contains particles, the particles move along the X axis due to the flow of the fluid.

[0070] On the other hand, Fig. 9 In the comparative example shown, particles can be captured at each node of the standing wave, and a large number of particles can be captured at the node on the -Z side where the inflow portion 92 is arranged. These particles can flow to the +X side due to the flow of the fluid and flow out from the first outflow portion 93.

[0071] However, in the fluid device 90 of the comparative example, a second outflow portion 94 is further provided on the +X side of the capture portion 91S. Fig. 9 As shown, the flow toward the second outflow portion 94 also increases, and the center of the vortex is generated near the corner of the -X side and +Z side of the capture portion 91S. In such a comparative example fluid device 90, in addition to the flow velocity X component from the inflow portion 92 toward the first outflow portion 93, the flow velocity Z component also increases. That is, in the comparative example fluid device 90, a large flow velocity Z component is generated in the Z direction where the acoustic radiation force of the standing wave acts, so the number of particles that overcome the acoustic radiation force and move in the Z direction increases.

[0072] Whether particles can be efficiently captured at the node position of the standing wave SW depends on the acoustic radiation force Fs of the standing wave SW and the fluid viscosity force Fu. The acoustic radiation force Fs is expressed by the following equation (1), and the fluid viscosity force Fu is expressed by equation (2).

[0073] Mathematical formula 1

[0074]

[0075] Fu=-6πηaZ…(2)

[0076] Here, V represents the volume of the fluid (the volume of the capturing portion 21S), P represents the sound pressure of the ultrasonic wave, and ρ 0 represents the density of the fluid, c n represents the speed of sound in the fluid, k represents the wave number of the ultrasonic wave (the inverse of the wavelength λ of the ultrasonic wave), z represents the position coordinate in the Z direction, Z represents the Z component of the flow velocity, η represents the viscosity of the fluid, and a represents the diameter of the particle. In addition, B = 3 (ρ-ρ 0 ) / (2ρ+ρ 0 ), ρ represents the density of the particles.

[0077] The allowable value |Z| of the flow velocity Z component at which the particles do not move in the Z direction relative to the sound pressure P of the ultrasonic wave applied by the ultrasonic wave applying unit 30 is expressed by the following equation (3).

[0078] Mathematical formula 2

[0079]

[0080] For example, when P=550kPa, |Z| is approximately 0.01m / s. By making the Z component of the fluid flow velocity less than 0.01m / s, the acoustic radiation force of the standing wave SW can be used to gather the particles at the node position and suppress movement in the Z direction due to the fluid flow velocity.

[0081] exist Fig. 9 In the comparative example shown, as described above, the fluid flowing from the inflow portion 92 into the capture portion 91S flows not only to the first outflow portion 93 but also to the second outflow portion 94, and the flow velocity Z component becomes larger. In this case, sometimes at a lower flow rate, the flow velocity Z component exceeds 0.01 m / s, and the particles overcome the acoustic radiation force of the standing wave and flow in the Z direction, and the capture efficiency of the standing wave on the particles is reduced. Therefore, in order to improve the capture efficiency of the particles, it is necessary to connect other fluid devices 90 to the second outflow portion 94, and the device is enlarged. Alternatively, the driving voltage of the ultrasonic application portion 95 can also be increased to increase the acoustic radiation force, but in this case, the increase in power consumption becomes a technical problem.

[0082] In contrast, in this embodiment, if Figure 7 and Figure 8 As shown in FIG. 1 , the maximum flow velocity Z component is 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, the flow velocity X component is sufficiently larger than the flow velocity Z component, so that the particles can be moved to the +X side in a state captured at the node position of the standing wave SW. Therefore, in the fluid device 10 of this embodiment, a concentrated fluid with a high particle concentration can be made to flow out from the first outflow portion 25 using a single fluid device 10 and a smaller driving power.

[0083] also, Figure 7 The flow velocity Z component with a negative value is flowing toward the X axis (center), so it will not be a problem. Figure 8 The reason why the flow velocity X component at the position of x=0 is low is that it represents the flow velocity at the boundary position between the inflow portion 24 and the wall surface of the negative-side wall portion 22 .

[0084] Effects of this embodiment

[0085] The fluid device 10 of this embodiment includes a main body 20 and an ultrasonic wave applying part 30. The main body 20 has a flow channel for fluid flow. The ultrasonic wave applying part 30 is provided on the flow channel wall forming the flow channel of the main body 20, and transmits ultrasonic waves in the Z direction to form a standing wave SW in the flow channel. The main body 20 has a portion where the ultrasonic wave applying part 30 is arranged as a capture part 21S, and has an inflow part 24 for allowing fluid to flow into the capture part 21S in the X direction, a first outflow part 25 for allowing concentrated fluid containing a large number of particles captured by the standing wave SW to flow out, and a second outflow part 26 for allowing a diluted fluid having a lower concentration of particles than the concentrated fluid to flow out from the capture part 21S. The inflow part 24 is provided on the negative side wall part 22 on the -X side of the capture part 21S, the first outflow part 25 is provided on the positive side wall part 23 on the +X side of the capture part 21S, and the second outflow part 26 is provided on the negative side wall part 22 at a position different from the inflow part 24.

[0086] In such a configuration, the fluid flowing from the inlet 24 into the capture portion 21S forms a vortex due to the rapidly expanding flow channel width, and has a velocity component not only in the X direction but also in the Z direction. However, in the present embodiment, only the first outflow portion 25 is provided on the +X side, and the second outflow portion 26 is provided on the -X side. Therefore, in the flow velocity of the fluid flowing from the inflow portion 24 into the capture portion 21S along the X-axis, the velocity X component toward the first outflow portion 25 becomes dominant, and the velocity Z component becomes sufficiently small. Therefore, it is possible to suppress the undesirable situation that the particles overcome the acoustic radiation force of the standing wave SW and move in the Z direction. Therefore, for example, it is possible to make a high-concentration concentrated fluid flow out from the first outflow portion 25 without connecting a plurality of fluid devices 10 or increasing the driving voltage of the ultrasonic application portion 30.

[0087] In the present embodiment, the first outflow portion 25 is disposed at a position facing the inflow portion 24 with the trapping portion 21S interposed therebetween. That is, the inflow portion 24 and the first outflow portion 25 are respectively provided along the X-axis. Thus, the fluid flows from the inflow portion 24 toward the first outflow portion 25 along the X-axis, and an increase in the flow velocity component in the Z direction can be suppressed.

[0088] In the present embodiment, the aperture diameter W2 of the first outflow portion 25 is larger than the aperture diameter W1 of the inflow portion 24.

[0089] 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, the fine particles that have not flowed out from the first outflow portion 25 may move in the Z direction and then flow out from the second outflow portion 26. In contrast, in the present embodiment, since the aperture diameter W2 of the first outflow portion 25 is sufficiently large, the concentrated fluid with a high fine particle concentration can flow out from the first outflow portion 25 by causing the fine particles trapped (aggregated) at the node positions of the standing wave SW to directly flow in the X-axis direction.

[0090] 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.

[0091] Therefore, the amount of fluid flowing out from the second outflow portion 26 can be increased, and thus 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, resulting in a decrease in the concentration of the fine particles in the concentrated fluid. In addition, since the flow velocity near the second outflow portion 26 increases, a flow directly from the vicinity of the inflow portion 24 toward the second outflow portion 26 is generated, thereby increasing the Z-direction component of the flow velocity. In contrast, 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 near the second outflow portion 26 does not become significantly fast, and an increase in the Z-direction component of the flow velocity is also suppressed, and an improvement in the trapping efficiency of the fine particles can be achieved.

[0092] In addition, the aperture diameter W3 of the second outflow portion 26 is larger than the aperture diameter W2 of the first outflow portion 25.

[0093] 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. Therefore, compared with the case of W2 < W3, the concentration of the fine particles in the concentrated fluid flowing out from the first outflow portion 25 becomes lower. In contrast, by setting W2 < W3, an adverse situation in which the concentration in the concentrated fluid becomes lower can be suppressed.

[0094] In the present embodiment, a pair of second outflow 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 inflow portion 24. More specifically, the pair of second outflow portions 26 are arranged in the Z direction and are provided at positions symmetrical with respect to the X axis in the YZ plane.

[0095] Thus, the flow of the fluid can be made symmetrical in the area on the +Z side and the area on the -Z side of the capture portion 21S. That is, the positions and flow channel distributions of the vortices formed by the flow of the fluid are roughly the same, so the flow velocities on the +Z side and the -Z side are balanced, and the undesirable situation that the Z-direction component of the flow velocity increases can be suppressed.

[0096] In the present embodiment, when the capturing portion 21S is viewed along the X direction, the ultrasonic wave applying unit 30 forms a standing wave SW in which the position of the node overlaps with the first outflow portion 25 .

[0097] That is, in the present embodiment, the position of the node of the standing wave SW is set on the X-axis, and the center of the first outflow portion 25 is set on the X-axis.

[0098] As described above, in this embodiment, the X-direction component of the flow velocity along the X-axis is large, and the particles captured at the node position of the standing wave SW can be pushed by the flow velocity to flow toward the first outflow portion 25 and flow out. As a result, a concentrated fluid with a high concentration of particles can flow out from the first outflow portion 25.

[0099] Second embodiment

[0100] Next, a second embodiment will be described.

[0101] The first embodiment described above is an example in which the ultrasonic wave applying unit 30 is arranged on the +Z side of the capturing unit 21S and a standing wave SW is formed in the Z direction. In this case, the acoustic radiation force of the standing wave SW acts to gather the particles in the XY plane passing through the X axis, and the particles can be suppressed from overcoming the acoustic radiation force and moving in the Z direction. On the other hand, the acoustic radiation force does not act in the Y direction. Therefore, assuming that the particles diffuse in the Y direction, the particles retained in the capturing unit 21S increase, and the concentration of the particles flowing out of the first outflow unit 25 decreases. In addition, since the X-direction component of the flow velocity along the X axis is large enough, the particles diffuse in the Y direction are small, and even if the particles diffuse in the Y direction, as described in the first embodiment, the particles move in a manner returning to the X axis. Therefore, it is possible to suppress the particles from flowing out of the second outflow unit 26.

[0102] The second embodiment is different from the first embodiment described above in that a standing wave is also formed in the Y direction.

[0103] Fig.10It is a perspective view showing a fluid device 10A according to a second embodiment.

[0104] exist Fig.10 In the embodiment, the first outflow portion 25 is concealed by the front side wall portion 23 , but is provided at a position opposite to the inflow portion 24 on the X-axis and connected to the capture portion 21S as in the first embodiment.

[0105] In addition, in this embodiment, if Fig.10 As shown, four second outflow portions 26 are arranged on the periphery of the inflow portion 24 in the negative side wall portion 22. Two of the four second outflow portions 26 are arranged along the Z direction as in the first embodiment, and each is equidistant from the X axis. That is, two of the four second outflow portions 26 are arranged along the Z direction and are arranged at positions that are point-symmetrical with respect to the X axis (inflow portion 24). On the other hand, the other two of the four second outflow portions 26 are arranged along the Y direction and are arranged at positions that are point-symmetrical with respect to the X axis (inflow portion 24). That is, the four second outflow portions 26 are arranged rotationally symmetrically with the X axis (inflow portion 24) as the center.

[0106] Furthermore, in this embodiment, in addition to the ultrasonic wave applying unit 30 that forms the standing wave SW in the Z direction, a second ultrasonic wave applying unit 30A (second ultrasonic element) is provided that transmits ultrasonic waves in the Y direction and forms the standing wave in the Y direction. The second ultrasonic wave applying unit 30A is provided in any one of the openings 211A (the second ultrasonic element) that are opposite in the Y direction in the central portion 21 of the main body 20. Fig.10 In addition, the specific structure of the second ultrasonic applying unit 30A is the same as that of the ultrasonic applying unit 30.

[0107] In such a fluid device 10A, in the capture section 21S, particles are collected and captured at the intersection of the node of the standing wave formed in the Z direction and the node of the standing wave formed in the Y direction. When each standing wave is a first-order standing wave, the intersection of each node coincides with the X-axis, so the particles are collected along the X-axis and captured.

[0108] Therefore, in the present embodiment, by suppressing the dispersion of the particles in the Y direction, it is possible to suppress the accumulation of the particles in the capturing portion 21S, and it is possible to discharge a concentrated fluid having a higher particle concentration from the first outflow portion 25 .

[0109] Effects of this embodiment

[0110] The fluid device 10A of this embodiment further includes a second ultrasonic wave applying unit 30A that transmits ultrasonic waves in the Y direction of the capture unit 21S of the body 20A to form standing waves in the Y direction. The second outflow units 26 are provided at positions rotationally symmetrical with respect to the inflow unit 24 in the negative side wall 22 of the capture unit 21S.

[0111] Thus, in this embodiment, the particles contained in the fluid flowing in from the inflow section 24 can be gathered on the X-axis and captured. That is, the particles are not dispersed not only in the Z direction but also in the Y direction, and the particles flowing in from the inflow section 24 can be more efficiently transported to the first outflow section 25 located on the X-axis, and the particle concentration of the concentrated fluid flowing out from the first outflow section 25 can be further increased.

[0112] Modifications

[0113] The present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention and configurations obtained by appropriately combining the embodiments are included in the present invention.

[0114] Modification 1

[0115] In the first embodiment and the second embodiment, the configuration in which a plurality of second outflow portions 26 are provided is exemplified, but the present invention is not limited thereto.

[0116] Fig.11 1 is a perspective view showing a schematic structure of a main body 20B of a fluid device according to Modification 1. Fig.12 1 is a diagram showing the distribution of the flow velocity and flow direction of the fluid when the fluid is allowed to flow into the main body 20B of the fluid device. Fig.13 1 is a diagram showing a flow velocity Z component in an extension of the inflow portion 24 of the fluid device in the X direction.

[0117] The main body 20B of the fluid device according to the first modification example includes a central portion 21, a negative side wall portion 22, and a positive side wall portion 23, similarly to the first and second embodiments. The capture portion 21S is formed by fixing an ultrasonic applying portion 30 and a flow channel wall portion 40 (not shown) to the central portion 21. Fig.13 In the figure, the ultrasonic wave applying unit 30 and the flow channel wall portion 40 are omitted.

[0118] Furthermore, in the fluid device of Modification 1, a second outflow portion 26 connected to the capture portion 21S is provided in the negative side wall portion 22. Specifically, when the ultrasonic wave is transmitted to the capture portion 21S along the Z direction by the ultrasonic wave applying portion 30 to form a standing wave, the second outflow portion 26 is arranged on the +Z side (or -Z side) of the inflow portion 24 in the negative side wall portion 22.

[0119] In addition, when there is only one second outflow portion 26, the inflow portion 24 is preferably provided at the end of the negative side wall portion 22 in the Z direction from the perspective of balancing the flow velocity distribution of the fluid flowing in the capture portion 21S. Fig.11In the example of , 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 to the inflow portion 24 across the capture portion 21S. Preferably, it is provided on the -Z side of the positive side wall portion 23.

[0120] Furthermore, as a standing wave formed by the ultrasonic applying part 30, a second-order or higher standing wave is formed. In the standing wave of the first-order mode, the position of the node becomes the center of the capturing part 21S in the Z direction, and becomes a position that is not opposite to the first outflow part 25 (a position deviated from the center). In this case, a part of the particles captured at the node position of the standing wave may move to the +Z side. In contrast, a second-order or higher standing wave is formed, and at least one node is formed at a position overlapping with the first outflow part 25 when viewed from the X direction.

[0121] Therefore, if Fig.12 and Fig.13 As shown, the particles can be moved to the +X side by the flow of the fluid and flow out from the first outflow portion 25 .

[0122] In addition, in this example, a main body 20B is illustrated that has an inflow portion 24 at the -Z side end of the capture portion 21S, a first outflow portion 25 at the -Z side end of the capture portion 21S, and a second outflow portion 26 at the +Z side end of the capture portion 21S, but the positions of the inflow portion 24, the first outflow portion 25, and the second outflow portion 26 may be moved toward the vicinity of the center of the capture portion 21S in the Z direction. However, in this case, the flow channel distribution in the capture portion 21S, that is, the distribution of the flow velocity Z component, may be complicated. Therefore, in the case where only one second outflow portion 26 is provided as in Modification Example 1, it is preferred to adopt a configuration in which the inflow portion 24 and the first outflow portion 25 are provided at the -Z side end, and the second outflow portion 26 is provided at the +Z side end.

[0123] In the fluid device of modification example 1, since there is only one second outflow portion 26, the number of tubes connected to the fluid device can be reduced compared to the first embodiment or the second embodiment. That is, when the fluid device is assembled in a particle recovery device that recovers particles from a fluid, for example, the inflow portion 24, the first outflow portion 25, and the second outflow portion 26 each require a tube for the fluid to circulate. Therefore, if the number of tubes connected in the particle recovery device increases, the structure becomes more complicated and the device becomes larger. In contrast, in the fluid device of modification example 1, the number of second outflow portions 26 is small, and the structure of the particle recovery device can be simplified and miniaturized accordingly.

[0124] Modification 2

[0125] In the first embodiment described above, by Figure 2An example of the main body 20 is shown, but as long as the positions of the inlet portion 24, the first outflow portion 25 and the second outflow portion 26 relative to the capture portion 21S are the same, the flow path shape of the inlet portion 24 and the second outflow portion 26 in the negative side wall portion 22 and the flow path shape of the first outflow portion 25 in the positive side wall portion 23 are not particularly limited.

[0126] Figures 14 to 16 It is a perspective view showing an example of main bodies 20C, 20D, and 20E of a fluid device according to Modification 2.

[0127] For example, in Fig.14 In the main body 20C shown, the second outflow portion 26 on the +Z side has a flow path shape that extends from the capture portion 21S along the -X side in parallel with the X axis in the negative side wall portion 22, and has a bent portion 262 bent from its front end (-X side end) toward the +Z side, and further extends from the bent portion 262 to the -X side end surface of the negative side wall portion 22. The second outflow portion 26 on the -Z side also has a flow path shape that has a bent portion 262 bent toward the -Z side, and further extends from the bent portion 262 to the -X side end surface of the negative side wall portion 22.

[0128] In addition, Fig.15 In the main body 20D shown, the second outflow portion 26 on the +Z side has a flow path shape as follows: in the negative side wall portion 22, there is an inclined portion 263 that is inclined toward the +Z side as it moves away from the capture portion 21S, and then extends from the inclined portion 263 to the -X side end surface of the negative side wall portion 22. The second outflow portion 26 on the -Z side also has a flow path shape as follows: there is an inclined portion 263 that is inclined toward the -Z side as it moves away from the capture portion 21S, and then extends from the inclined portion 263 to the -X side end surface of the negative side wall portion 22.

[0129] In these main bodies 20C and 20D, since the distance between the inflow connection part 241 corresponding to the inflow part 24 and the second outflow connection part 261 can be increased, when connecting the inflow pipe or the second outflow pipe to the main body 20C and 20D, the connection work can be reduced.

[0130] exist Fig.16 In the main body 20E shown, the second outflow portion 26 on the +Z side is extended from the capture portion 21S toward the -X side in the negative side wall portion 22, and has a bent portion 264 bent toward the +Z side and the +X side at its front end, and the second outflow portion 26 is extended to the +X side end surface of the positive side wall portion 23 through the bent portion 264. The second outflow portion 26 on the -Z side is also extended to the +X side end surface of the positive side wall portion 23 through the bent portion 264. Thus, the first outflow connection portion 251 of the first outflow portion 25 and the second outflow connection portion 261 of the second outflow portion 26 are provided on the +X side of the main body 20E.

[0131] Therefore, in the fluid device using the main body 20E of this example, an inflow pipe for introducing fluid can be connected to the -X side end face, and a first outflow pipe and a second outflow pipe for discharging the concentrated fluid and the diluted fluid can be connected to the +X side end face. That is to say, the outflow connection ports flowing out from the fluid device can be concentrated in the same direction.

[0132] Modification Example 3

[0133] In the first embodiment, an example is shown in which the cross-section of the capture part 21S observed in the YZ plane is rectangular, but it is not limited thereto. For example, the flow path wall parts 40 on the ±Y sides that do not participate in the formation of the standing wave may not be planar but curved. In addition, as the flow path wall parts 40 on the ±Y sides, they may also be formed of a material with low ultrasonic reflection efficiency or sound absorption properties.

[0134] In addition, in the second embodiment, an example is shown in which the cross-section of the capture part 21S in the YZ plane is rectangular in order to form a standing wave with respect to the Y direction and the Z direction. However, for example, it may also be formed in a polygonal shape such as a hexagon, and standing waves may be formed respectively in combinations of a pair of surfaces that face each other across the capture part 21S and are parallel. For example, in the case where the cross-section is hexagonal when observed, standing waves may also be formed on each axis that is orthogonal to the X axis and spaced 120 degrees apart.

[0135] Modification Example 4

[0136] In the first embodiment and the second embodiment, examples of forming a standing wave of the first order mode are shown. However, as described above, as long as there is one or more nodes overlapping at a position overlapping with the first outflow part 25 when observed from the X direction, a standing wave of a higher order may also be formed.

[0137] Modification Example 5

[0138] In the first embodiment, an example is shown in which the aperture diameters W1, W2, and W3 of the inflow part 24, the first outflow part 25, and the second outflow part 26 are in the relationship of W1 < W2 < W3, but it is not limited thereto.

[0139] For example, as long as the total cross-sectional area of the second outflow part 26 is larger than that of the first outflow part 25, it may be set to W2 = W3, or it may also be set to W2 > W3.

[0140] Summary of the present disclosure

[0141] The first mode of the fluid device involved in the present disclosure uses ultrasound to capture particles contained in a fluid, and comprises: a main body, having a flow channel for the fluid to flow; and an ultrasonic element, which is arranged on a flow channel wall of the flow channel forming the main body, and transmits ultrasound in a first direction to form a standing wave in the flow channel, the main body uses a portion where the ultrasonic element is configured as a capturing portion, and comprises: an inflow portion, which allows the fluid to flow into the capturing portion along a second direction intersecting the first direction; a first outflow portion, which allows a concentrated fluid containing the particles captured by the standing wave to flow out of the capturing portion; and a second outflow portion, which allows a diluted fluid with a lower concentration of the particles than the concentrated fluid to flow out of the capturing portion, the inflow portion being arranged on the negative side of the second direction of the capturing portion, the first outflow portion being arranged on the positive side of the second direction of the capturing portion, and the second outflow portion being arranged on the negative side of the second direction of the capturing portion at a position different from the inflow portion.

[0142] In such a fluid device, the fluid flowing from the inlet into the capture part forms a vortex due to the rapidly expanding flow channel width. Therefore, there is a velocity component not only in the X direction but also in the Z direction. However, in this embodiment, only the first outflow part is provided on the positive side of the second direction, and the second outflow part is provided on the negative side. Therefore, on the axis of the inflow part of the fluid flowing from the inflow part into the capture part, the velocity component in the second direction toward the first outflow part becomes dominant, and the velocity component in the first direction can be made sufficiently small. Therefore, it is possible to suppress the undesirable situation that the particles overcome the acoustic radiation force of the standing wave and move along the first direction. Therefore, for example, it is possible to make a high-concentration concentrated fluid flow out from the first outflow part without connecting a plurality of fluid devices or increasing the driving voltage of the ultrasonic element. That is, it is possible to provide a small-sized fluid device that has high efficiency in capturing particles at a low cost.

[0143] In the fluid device of this aspect, it is preferable that the first outflow portion is provided at a position facing the inflow portion across the capture portion.

[0144] Thus, the nodes of the standing wave formed coaxially with the inflow portion can be used to capture particles contained in the fluid flowing in from the inflow portion. In addition, as described above, the flow velocity component in the first direction becomes dominant on the axis of the inflow portion, so the particles captured at the node position of the standing wave can be moved to the first outflow portion by the flow of the fluid, and a high-concentration concentrated fluid can be discharged from the first outflow portion 25.

[0145] In the fluid device of this aspect, it is preferable that the hole diameter of the first outflow portion is larger than the hole diameter of the inflow portion.

[0146] If the aperture of the first outflow portion is smaller than the aperture of the inflow portion, the amount of fluid flowing out of the first outflow portion becomes smaller. In this case, the particles that have not flowed out of the first outflow portion may flow out of the second outflow portion after moving in the first direction. In contrast, in this method, since the aperture of the first outflow portion is large enough, the particles captured at the node position of the standing wave are directly made to flow in the second direction, and the concentrated fluid with a high particle concentration can be made to flow out of the first outflow portion.

[0147] In the fluid device of this aspect, it is preferable that the hole diameter of the second outflow portion is larger than the hole diameter of the inflow portion.

[0148] Assuming that the aperture of the second outflow portion is smaller than the aperture of the inflow portion, the fluid that cannot flow out of the second outflow portion flows out of the first outflow portion, so the concentration of particles in the concentrated fluid is reduced. In addition, since the flow velocity near the second outflow portion increases, a flow directly from the vicinity of the inflow portion toward the second outflow portion is generated, resulting in an increase in the Z-direction component of the flow velocity. In contrast, in this method, the fluid can be appropriately caused to flow out from the second outflow portion. Furthermore, the flow velocity near the second outflow portion will not become significantly faster, and the increase in the flow velocity component toward the first direction is also suppressed, thereby achieving an improvement in the capture efficiency of particles.

[0149] In the fluid device of this aspect, it is preferable that the hole diameter of the second outflow portion is larger than the hole diameter of the first outflow portion.

[0150] Assuming that the pore size of the first outflow portion is larger than the pore size of the second outflow portion, the outflow amount of the fluid from the second outflow portion decreases, and the outflow amount of the fluid from the first outflow portion increases. Therefore, the particle concentration of the concentrated fluid flowing out of the first outflow portion decreases. In contrast, in this method, the concentration reduction of the concentrated fluid can be suppressed.

[0151] In the fluid device of this aspect, it is preferable that the inflow portion is provided at the center of the capturing portion when the capturing portion is viewed along the second direction.

[0152] Thus, the velocity distribution of the fluid flowing in from the inflow portion is symmetrical with respect to the axis of the inflow portion (axis parallel to the second direction). Therefore, the stress acting on the particles by the velocity is balanced, and the increase of the velocity component in the first direction can be suppressed.

[0153] In the fluid device of this aspect, it is preferable that a plurality of second outflow portions are provided, and the second outflow portions are provided at positions symmetrical with respect to the inflow portion on the negative side of the capture portion in the second direction.

[0154] Thus, similar to the above method, the velocity distribution of the fluid flowing in from the inlet portion can be made symmetrical with respect to the axis of the inlet portion (the axis parallel to the second direction), and the stress acting on the particles by the flow velocity is balanced, thereby suppressing the increase of the velocity component in the first direction.

[0155] In the fluid device of this aspect, the second outflow portions are respectively provided at positions that are point-symmetrical with respect to the center of the inflow portion along the first direction.

[0156] In this embodiment, the second outflow portion is point-symmetrical along the first direction in which the standing wave is formed by the ultrasonic application portion. Therefore, the velocity distribution of the fluid in the first direction can be symmetrical with respect to the axis of the inflow portion (the axis parallel to the second direction), and the increase of the velocity component in the first direction can be suppressed.

[0157] In the fluid device of this embodiment, there is a second ultrasonic element, which is arranged on the flow channel wall of the flow channel forming the main body, and transmits ultrasonic waves along a third direction orthogonal to the first direction and the second direction of the capturing portion to form a standing wave along the third direction. The second outflow portion is respectively arranged on the negative side of the capturing portion at a position that is rotationally symmetrical with respect to the inflow portion.

[0158] In this method, by forming standing waves along the first direction and the third direction, particles can be captured at the central axis of the capture portion where the nodes of these standing waves overlap, that is, the axis of the inflow portion. Therefore, even if a second outflow portion that clamps the inflow portion is provided not only at the position of the inflow portion along the first direction but also at the position of the inflow portion along the third direction, the movement of particles in the first direction and the third direction can be restricted. As a result, a concentrated fluid with a higher concentration can flow out from the first outflow portion.

[0159] In the fluid device of this aspect, it is preferable that the ultrasonic element forms the standing wave in which a node position overlaps with the first outflow portion when the capturing portion is viewed along the second direction.

[0160] In this embodiment, the flow velocity component along the second direction is large, and the particles captured at the node position of the standing wave can be pushed toward the first outflow portion by the flow velocity to flow out. Thus, concentrated fluid with a high concentration of particles can flow out from the first outflow portion.

Claims

1. A fluid device, characterized in that: Using ultrasound to capture particles contained in fluids, it has: a main body having a flow channel for the fluid to flow; and an ultrasonic element, which is disposed on a flow channel wall of the flow channel forming the main body and transmits ultrasonic waves in a first direction to form standing waves in the flow channel, The main body has a portion where the ultrasonic element is disposed as a capture portion, and has: an inflow portion, causing the fluid to flow into the capture portion along a second direction intersecting the first direction; a first outflow portion that causes a concentrated fluid containing the particles captured by the standing wave to flow out from the capturing portion; as well as a second outflow portion for causing a dilution fluid having a lower concentration of the particles than the concentrated fluid to flow out from 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 disposed on the positive side of the capture portion in the second direction. The second outflow portion is provided at a position different from the inflow portion on the negative side of the capturing portion in the second direction.

2. The fluid device according to claim 1, wherein: The first outflow portion is provided at a position facing the inflow portion across the capture portion.

3. The fluid device according to claim 1, wherein: The aperture of the first outflow portion is larger than the aperture of the inflow portion.

4. The fluid device according to claim 1, wherein: The aperture of the second outflow portion is larger than the aperture of the inflow portion.

5. The fluid device according to claim 1, wherein: The aperture of the second outflow portion is larger than the aperture of the first outflow portion.

6. The fluid device according to claim 1, wherein: The inflow portion is provided at a center of the capturing portion when the capturing portion is viewed along the second direction.

7. The fluid device according to claim 1, wherein: A plurality of second outflow portions are provided, and the second outflow portions are provided at positions symmetrical with respect to the inflow portion on the negative side of the capture portion in the second direction.

8. The fluid device according to claim 7, wherein: The second outflow portions are respectively arranged at positions that are point-symmetrical with respect to a center of the inflow portion along the first direction.

9. The fluid device according to claim 7, wherein: The fluid device includes a second ultrasonic element, which is disposed on the flow channel wall of the flow channel forming the main body, transmits ultrasonic waves along a third direction orthogonal to the first direction and the second direction of the capture portion, and forms a standing wave along the third direction. The second outflow portions are respectively provided at positions which are rotationally symmetrical with respect to the inflow portion on the negative side of the capture portion.

10. The fluid device according to claim 1, wherein: When the capturing portion is viewed along the second direction, the ultrasonic element forms the standing wave in which the position of the node overlaps with the first outflow portion.

Images