Fluid device

Abstract

To provide a fluid device capable of improving concentration efficiency of fine particles.SOLUTION: A fluid device 10 separates microparticles in a fluid using ultrasonic waves. The fluid device 10 includes an inflow flow path 20 through which the fluid flows; a separation flow path 30 into which the fluid flows from the inflow flow path 20; a first outflow flow path 40 that causes the fluid to flow out from the separation flow path 30; a second outflow flow path 50 that causes the fluid to flow out from the separation flow path 30; and an ultrasonic transmitter 60 that transmits the ultrasonic waves to the separation flow path 30 and at least one of the inflow flow path 20 and the first outflow flow path 40, and forms a standing wave along a first direction in each flow path to which the ultrasonic waves were transmitted.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, in the fluidic device disclosed in Patent Document 1, an ultrasonic element transmits ultrasonic waves to form standing waves in the fluid in a separation channel, and particles in the fluid are trapped at the nodes of the standing waves due to the pressure gradient of the standing waves. The trapped particles are then discharged from the separation channel to a concentrated fluid outlet, and the diluted fluid is then discharged from the separation channel to a diluted fluid outlet. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-122480 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the fluidic device disclosed in Patent Document 1 is unable to control the behavior of microparticles immediately before they are trapped by a node of the standing wave in the separation channel or immediately after they are released from the node of the standing wave in the separation channel, and therefore the efficiency of concentrating microparticles is not sufficiently improved. [Means for solving the problem]

[0005] A fluidic device according to one aspect of the present disclosure is a fluidic device that separates microparticles in a fluid using ultrasound, and includes an inlet flow path through which a fluid flows, a separation flow path into which the fluid flows from the inlet flow path, a first outlet flow path through which the fluid flows out of the separation flow path, a second outlet flow path through which the fluid flows out of the separation flow path, and an ultrasound transmitting unit that transmits ultrasound to at least one of the inlet flow path or the first outlet flow path and the separation flow path, and forms standing waves along one direction in each flow path to which the ultrasound is transmitted. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a cross-sectional view schematically showing a fluidic device according to a first embodiment. [Figure 2] 6 is a graph showing a simulation result of sound pressure applied to particles in the first embodiment. [Figure 3] FIG. 10 is a cross-sectional view schematically showing a fluidic device according to a second embodiment. [Figure 4] FIG. 10 is a cross-sectional view schematically showing a fluidic device according to a third embodiment. [Figure 5] FIG. 10 is a cross-sectional view schematically showing a fluidic device according to a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, several embodiments of the present invention will be described with reference to the drawings. In the second and subsequent embodiments, the same components as those in the first embodiment will be denoted by the same reference numerals as those in the first embodiment, and the description thereof will be omitted or simplified.

[0008] [First embodiment] 1 is a cross-sectional view schematically illustrating a fluidic device 10 according to the present embodiment. As shown in FIG. 1, the fluidic device 10 includes an inlet channel 20, a separation channel 30, a first outlet channel 40, a second outlet channel 50, and an ultrasonic transmitter 60.

[0009] The fluidic device 10 of this embodiment acoustically focuses particles in a fluid flowing from the inlet channel 20 to the separation channel 30, and allows the fluid with concentrated particles to flow out from the first outlet channel 40, while allowing the fluid with diluted or removed particles to flow out from the second outlet channel 50. The fluid is not particularly limited, and may be any liquid such as water. The particles are not particularly limited, and may be, for example, microfibers or microplastics.

[0010] In this embodiment, the inlet flow channel 20, the separation flow channel 30, the first outlet flow channel 40, and the second outlet flow channel 50 are arranged along an arbitrary direction, and fluid flows along that direction. Here, the flow direction of the fluid in each flow channel is defined as the X direction, the upstream side of the flow direction of the fluid is defined as the -X side, and the downstream side of the flow direction of the fluid is defined as the +X side. Furthermore, the direction perpendicular to the X direction and in which standing waves SW1 to SW3 (described below) are formed is defined as the Z direction, with one side of the Z direction defined as the +Z direction and the other side of the Z direction defined as the -Z direction. Furthermore, the direction perpendicular to the Z direction and the X direction and the Z direction, respectively, is defined as the Y direction.

[0011] In this embodiment, the entire flow path including the inlet flow path 20, the separation flow path 30, the first outlet flow path 40, and the second outlet flow path 50 is mainly formed by the flow path member 11. The flow path member 11 is made of a material that can reflect ultrasonic waves in the fluid, for example, a material that has an acoustic impedance different from that of the fluid.

[0012] The inflow channel 20 is a channel that allows a fluid containing fine particles to flow into the separation channel 30. An inlet pipe (not shown) that introduces a fluid into the fluidic device 10 is connected to the −X side end of the inflow channel 20, and the +X side end of the inflow channel 20 is connected to the −X side end of the separation channel 30. The channel width L1 in the Z direction of the inflow channel 20 is defined by a pair of flat wall surfaces 21 and 22 that face each other in the Z direction.

[0013] The separation channel 30 is an intermediate channel that allows the fluid that has flowed in from the inlet channel 20 to flow out to each of the first outlet channel 40 and the second outlet channel 50. The channel width L2 of the separation channel 30 in the Z direction is determined by a pair of flat wall surfaces 31, 32 that face each other in the Z direction. The channel width L2 of the separation channel 30 is greater than the channel width L1 of the inlet channel 20. Furthermore, the wall surface 31 on the -Z side of the separation channel 30 is continuous with the wall surface 21 on the -Z side of the inlet channel 20 in the X direction.

[0014] The first outlet channel 40 and the second outlet channel 50 are channels for discharging fluid from the separation channel 30, and are connected in parallel to each other in the Z direction with respect to the +X side end of the separation channel 30.

[0015] The first outlet flow path 40 is disposed at a position opposite to the inlet flow path 20 in the Z direction across the separation flow path 30. In other words, the Z direction range in which the inlet flow path 20 is disposed is included in the Z direction range in which the first outlet flow path 40 is disposed. Furthermore, the +X side end of the first outlet channel 40 forms a concentration port 43 through which the fluid that has flowed in from the separation channel 30 flows out. The channel width L3 of the first outlet channel 40 in the Z direction is determined by a pair of flat wall surfaces 41, 42 that face each other in the Z direction. The channel width L3 of the first outlet channel 40 is greater than the channel width L1 of the inflow channel 20 and is smaller than the channel width L2 of the separation channel 30. Furthermore, the -Z side wall surface 41 of the first outlet channel 40 is continuous with the -Z side wall surface 31 of the separation channel 30 in the X direction.

[0016] The second outlet flow path 50 is disposed on the +Z side of the first outlet flow path 40. The +X side end of the second outlet flow path 50 forms a purification port 53 through which the fluid that has flowed in from the separation flow path 30 flows out. The flow path width L4 of the second outlet flow path 50 is defined by a pair of flat wall surfaces 51, 52 that face each other in the Z direction.

[0017] The first outflow flow path 40 and the second outflow flow path 50 are separated by a partition 112. In other words, the flow path member 11 has a partition 112 that separates the first outflow flow path 40 and the second outflow flow path 50. This partition 112 forms a wall surface 42 on the +Z side of the first outflow flow path 40 and a wall surface 51 on the -Z side of the second outflow flow path 50. In this embodiment, the total dimension of the flow path width L3 of the first outflow flow path 40, the flow path width L4 of the second outflow flow path 50, and the Z-direction dimension of the partition section 112 is equal to the flow path width L2 of the separation flow path 30.

[0018] The ultrasonic transmitter 60 is disposed across the inlet flow channel 20, the separation flow channel 30, and the first outlet flow channel 40, and transmits ultrasonic waves to these flow channels. Specifically, the ultrasonic transmitter 60 of this embodiment is configured with one ultrasonic element, and this ultrasonic element is provided in the flow channel member 11 so as to form each of the wall surfaces 21, 31, 41 of the inlet flow channel 20, the separation flow channel 30, and the first outlet flow channel 40. The ultrasonic transmitter 60 does not have to be disposed over the entire length of the inflow channel 20, but only needs to be disposed so as to overlap at least a region of the inflow channel 20 that is adjacent to the separation channel 30. Similarly, the ultrasonic transmitter 60 does not have to be disposed over the entire length of the first outflow channel 40, but only needs to be disposed so as to overlap at least a region of the first outflow channel 40 that is adjacent to the separation channel 30.

[0019] The specific configuration of the ultrasonic element that constitutes the ultrasonic transmission unit 60 is not particularly limited. The ultrasonic element of this embodiment may be a bulk ultrasonic element or a thin-film ultrasonic element. A thin-film ultrasonic element comprises a substrate on which one or more openings are formed, a thin-film vibration unit that covers each opening of the substrate, and a piezoelectric element disposed in each vibration unit, and the combination of the vibration unit and the piezoelectric element constitutes an ultrasonic transducer. For example, the thin-film ultrasonic element may comprise one ultrasonic transducer, or may comprise multiple ultrasonic transducers arranged in an array.

[0020] In this embodiment, the ultrasonic waves transmitted from the ultrasonic transmitter 60 have a frequency capable of forming Z-direction standing waves SW1 to SW3 in each of the inlet channel 20, the separation channel 30, and the first outlet channel 40. In other words, the inlet channel 20, the separation channel 30, and the first outlet channel 40 each have channel widths L1, L2, L3 such that the ultrasonic waves transmitted from the ultrasonic transmitter 60 are reflected in the Z direction to form the Z-direction standing waves SW1 to SW3. In Fig. 1, the nodes of the standing waves SW1 to SW3 are shown as dotted lines (lines parallel to the X direction), and the particles in the fluid are shown as black circles.

[0021] Here, the widths L (L1, L2, L3) of the inlet flow channel 20, the separation flow channel 30, and the first outlet flow channel 40 are designed to satisfy the following formula (1): f is the frequency of the ultrasonic waves transmitted from the ultrasonic transmitter 60, C0 is the speed of sound in the fluid, and n is the order of the standing waves SW1 to SW3 in each flow channel.

number

[0022] Converting the above (1), the flow path widths L (L1, L2, L3) of the inlet flow path 20, the separation flow path 30, and the first outlet flow path 40 satisfy the following formula (2). That is, each flow path width L is designed to be an integer multiple of half the wavelength (λ / 2) of the ultrasonic wave transmitted from the ultrasonic transmitter 60.

number

[0023] Furthermore, in this embodiment, the frequencies of the standing waves SW1 to SW3 formed in the inlet flow path 20, the separation flow path 30, and the first outlet flow path 40 are equal to one another, so the following equation (3) holds: n1 is the order of the standing wave SW1 in the inlet flow path 20, n2 is the order of the standing wave SW2 in the separation flow path 30, and n3 is the order of the standing wave SW3 in the first outlet flow path 40.

number

[0024] According to the above formula (3), the channel width L1 of the inflow channel 20, the channel width L2 of the separation channel 30, and the channel width L3 of the first outflow channel 40 satisfy the relationships of the following formulas (4) and (5).

number

[0025] In this embodiment, the channel width L2 of the separation channel 30 and the channel width L3 of the first outlet channel 40 are each designed to be an integer multiple of the channel width L1 of the inlet channel 20. Therefore, n2 / n1 and n3 / n1 in the above formulas (4) and (5) are each an integer. According to this flow channel design, a node of standing wave SW1 in inflow channel 20 is positioned at the same position in the Z direction as any node of standing wave SW2 in separation channel 30 and any node of standing wave SW3 in first outlet channel 40. In other words, the standing waves SW1 to SW3 formed in inflow channel 20, separation channel 30 and first outlet channel 40 have nodes positioned at the same positions in the Z direction as one another.

[0026] For example, in this embodiment, the order n1 of the standing wave SW1 formed in the inflow channel 20 is 1, the order n2 of the standing wave SW2 formed in the separation channel 30 is 4, and the order n3 of the standing wave SW3 formed in the first outflow channel 40 is 2. For this reason, the node of the standing wave SW1 in the inflow channel 20 is positioned at a position equal in the Z direction to the first node from the -Z side of the standing wave SW2 in the separation channel 30 (specifically, the first node counting in the +Z direction from the wall surface 31 on the -Z side of the separation channel 30) and the first node from the -Z side of the standing wave SW3 in the first outflow channel 40 (specifically, the first node counting in the +Z direction from the wall surface 41 on the -Z side of the first outflow channel 40).

[0027] Note that the number of nodes of the standing waves SW1 to SW3 formed in each of the inflow channel 20, the separation channel 30, and the first outflow channel 40 is not particularly limited. However, each of the standing waves SW2 in the separation channel 30 and the standing wave SW3 in the first outflow channel 40 preferably has a plurality of nodes.

[0028] [Operation of the fluid device 10] In the fluid device 10 of the present embodiment, when the ultrasonic transmitter 60 starts transmitting ultrasonic waves, standing waves SW1 to SW3 are formed in each of the inflow channel 20, the separation channel 30, and the first outflow channel 40 as shown in FIG. 1.

[0029] The inflow channel 20 is supplied with a fluid containing fine particles from an arbitrary supply source (not shown), and the supplied fluid flows through the inflow channel 20 along the X direction. The fine particles in the fluid flowing through the inflow channel 20 are captured at the node positions of the standing wave SW1 in at least the region immediately before the separation channel 30, and while being captured, they move toward the separation channel 30 along the flow of the fluid.

[0030] Since the channel width is expanded from the inflow channel 20 to the separation channel 30 (L1 < L2), the fluid flowing from the inflow channel 20 into the separation channel 30 flows so as to spread in the +Z direction. At this time, most of the fine particles in the fluid are released from the state of being captured at the node positions of the standing wave SW1 in the inflow channel 20, and before spreading in the +Z direction, they are captured at the first node from the -Z side of the standing wave SW2 in the separation channel 30 (specifically, the first node counted from the wall surface 31 on the -Z side of the separation channel 30 in the +Z direction), and move along the flow of the fluid toward the first outflow channel 40. Among the fine particles in the fluid, the fine particles that have spread in the +Z direction together with the fluid are captured at the second node from the -Z side of the standing wave SW2 (specifically, the second node counted from the wall surface 31 on the -Z side of the separation channel 30 in the +Z direction), and move along the flow of the fluid toward the first outflow channel 40. That is, in the separation channel 30, the fine particles in the fluid behave differently from the fluid, and their movement in the +Z direction is suppressed.

[0031] Most of the fine particles in the fluid flowing from the separation channel 30 into the first outlet channel 40 are immediately captured at the first or second node from the -Z side of the standing wave SW2 (specifically, the first or second node counting in the +Z direction from the -Z side wall surface 41 of the first outlet channel 40) as soon as they are released from the state where they were captured at the first or second node from the -Z side of the standing wave SW3. Then, they flow along with the fluid through the first outlet channel 40 in the X direction and head toward the concentration port 43. Therefore, the concentration port 43 discharges a concentrated fluid, which is a fluid in which the fine particles are concentrated.

[0032] On the other hand, the fluid that flows from the separation channel 30 into the second outlet channel 50 flows through the second outlet channel 50 in the X direction and heads toward the purification port 53. As described above, the particulates in the separation channel 30 are prevented from moving in the +Z direction, so the fluid that flows from the separation channel 30 into the second outlet channel 50 contains almost no particulates. For this reason, the purification port 53 discharges a diluted fluid, which is a fluid from which the particulates have been diluted or removed.

[0033] [Effects of this embodiment] The fluidic device 10 of this embodiment is a fluidic device 10 that separates fine particles in a fluid using ultrasound, and is equipped with an inlet flow path 20 through which the fluid flows, a separation flow path 30 into which the fluid flows from the inlet flow path 20, a first outlet flow path 40 through which the fluid flows out of the separation flow path 30, a second outlet flow path 50 through which the fluid flows out of the separation flow path 30, and an ultrasound transmitting unit 60 that transmits ultrasound to the inlet flow path 20, the separation flow path 30 and the first outlet flow path 40, and forms standing waves along one direction (Z direction) in each flow path to which the ultrasound is transmitted.

[0034] In this configuration, standing waves SW1 to SW3 are formed in the inlet channel 20, the separation channel 30, and the first outlet channel 40, so that sound pressure can be applied appropriately to the particles not only in each channel but also at the boundary between adjacent channels. This allows the particles in the fluid to remain trapped at any node of the standing wave in each channel while they flow through the inlet channel 20, the separation channel 30, and the first outlet channel 40. Therefore, the behavior of the particles can be controlled immediately before they are trapped at the node of the standing wave SW2 in the separation channel 30 and immediately after they are released from the node of the standing wave SW2 in the separation channel 30, and the particles can be guided to the first outlet channel 40. Therefore, according to the fluidic device 10 of this embodiment, the efficiency of capturing fine particles is improved, and a concentrated fluid with a high concentration of fine particles can be discharged from the first outlet channel 40.

[0035] In this embodiment, the flow path width L1 of the inlet flow path 20 in one direction, the flow path width L2 of the separation flow path 30, and the flow path width L3 of the first outlet flow path 40 are each an integer multiple of half the wavelength of the ultrasonic waves transmitted from the ultrasonic transmitter 60. With this configuration, the standing waves SW1 to SW3 can be suitably formed in the inflow channel 20, the separation channel 30, and the first outflow channel 40, respectively.

[0036] In this embodiment, the channel width L2 of the separation channel 30 and the channel width L3 of the first outlet channel 40 are each an integer multiple of the channel width L1 of the inlet channel 20. With this configuration, the Z-direction position (Z position) of the node of standing wave SW1 in inflow channel 20 coincides with the Z position of any node of standing wave SW2 in separation channel 30 and the Z position of any node of standing wave SW3 in first outlet channel 40. This stabilizes the flow of fine particles from inflow channel 20 until they reach first outlet channel 40, thereby achieving high concentration efficiency.

[0037] Furthermore, the ultrasonic transmission unit 60 of this embodiment includes ultrasonic elements arranged across the inflow channel 20, the separation channel 30, and the first outflow channel 40. This allows the ultrasonic transmission unit 60 to be configured from a single ultrasonic element, thereby reducing the cost of the fluidic device 10.

[0038] 2 is a graph showing the results of a simulation to explain the effects of this embodiment. This simulation measures the sound pressure applied to the particles at the boundary between the separation channel 30 and the first outlet channel 40. In the simulation of the example, the sound pressure applied to the particles was measured when ultrasonic waves were transmitted to each of the separation channel 30 and the first outlet channel 40, while in the simulation of the comparative example, the sound pressure applied to the particles was measured when ultrasonic waves were transmitted only to the separation channel 30. In each of the example and comparative example, measurements were taken each time the channel width L2 of the separation channel 30 was increased by a predetermined interval until it reached a value (e.g., 5.0 mm) that satisfied the above formula (1) from a predetermined value (e.g., 4.7 mm).

[0039] 2, when the channel width L2 of the separation channel 30 satisfies the above formula (2) (for example, when it is 5.0 mm), in the example, a significantly larger sound pressure is applied to the particles than in the comparative example. That is, it is clear that in the example, sound pressure is suitably applied to the particles at the boundary between the separation channel 30 and the first outlet channel 40.

[0040] In this embodiment, the condition of the above formula (2) is such that a slight error is permissible as long as it is within a range in which fine particles can be captured. 2, the effect of the embodiment is achieved when the wavelength of the ultrasonic waves transmitted from the ultrasonic transmitter 60 is 1 mm and the channel width L2 of the separation channel 30 is 4.9 mm to 5.0 mm. Therefore, it is considered that an error of about 1 / 10 of the wavelength of the ultrasonic waves transmitted from the ultrasonic transmitter 60 is acceptable.

[0041] [Second embodiment] The second embodiment will be described with reference to Fig. 3. A fluidic device 10A of the second embodiment includes an ultrasonic wave transmitting section 60A having a different configuration from that of the first embodiment.

[0042] The ultrasonic transmitter 60A includes a plurality of ultrasonic elements, including a first ultrasonic element 61 arranged from the inflow channel 20 to the separation channel 30, and a second ultrasonic element 62 arranged from the separation channel 30 to the first outflow channel 40. Specifically, the first ultrasonic element 61 is provided on the channel member 11 so as to form a partial area of ​​the wall surface 21 of the inflow channel 20 (an area adjacent to the separation channel 30) and a partial area on the -X side of the wall surface 31 of the separation channel 30. The second ultrasonic element 62 is provided on the channel member 11 so as to form a partial area on the +X side of the wall surface 31 of the separation channel 30 and the wall surface 41 of the first outflow channel 40. Here, it is desirable that the first ultrasonic element 61 and the second ultrasonic element 62 are adjacent to each other in the X direction, but a gap in the X direction (i.e., a wall surface due to the flow path member 11) may exist between the first ultrasonic element 61 and the second ultrasonic element 62.

[0043] Each of the first ultrasonic element 61 and the second ultrasonic element 62 may be a bulk type ultrasonic element or a thin film type ultrasonic element, similar to the first embodiment.

[0044] In this embodiment, the first ultrasonic element 61 and the second ultrasonic element 62 preferably transmit ultrasonic waves of the same frequency, and form standing waves SW1 to SW3 in each of the inlet flow channel 20, the separation flow channel 30, and the first outlet flow channel 40. In the fluidic device 10A of the second embodiment described above, the efficiency of capturing fine particles can be improved, similarly to the first embodiment.

[0045] [Third embodiment] The third embodiment will be described with reference to Fig. 4. A fluidic device 10B of the third embodiment includes an ultrasonic wave transmitting section 60B having a different configuration from that of the first embodiment.

[0046] The ultrasonic transmitter 60B includes a plurality of ultrasonic elements, including a first ultrasonic element 63 provided in the inflow channel 20, a second ultrasonic element 64 provided in the separation channel 30, and a third ultrasonic element 65 provided in the first outflow channel 40. Specifically, the first ultrasonic element 63 is provided in the channel member 11 so as to form a partial region of the wall surface 21 of the inflow channel 20, specifically an area adjacent to the separation channel 30. The second ultrasonic element 64 is provided in the channel member 11 so as to form the wall surface 31 of the separation channel 30. The third ultrasonic element 65 is provided in the channel member 11 so as to form the wall surface 41 of the first outflow channel 40. Here, it is desirable that the first ultrasonic element 63 and the second ultrasonic element 64 are adjacent to each other in the X direction, but a gap in the X direction (i.e., a wall surface due to the flow path member 11) may exist between the first ultrasonic element 63 and the second ultrasonic element 64. The same applies to the positional relationship between the second ultrasonic element 64 and the third ultrasonic element 65.

[0047] Each of the first ultrasonic element 63, the second ultrasonic element 64, and the third ultrasonic element 65 may be a bulk type ultrasonic element or a thin film type ultrasonic element.

[0048] In this embodiment, the first ultrasonic element 63, the second ultrasonic element 64, and the third ultrasonic element 65 preferably transmit ultrasonic waves of the same frequency, forming standing waves SW1 to SW3 within each of the inlet flow path 20, the separation flow path 30, and the first outlet flow path 40. In the fluidic device 10B of the third embodiment described above, the efficiency of capturing fine particles can be improved, similarly to the first embodiment.

[0049] [Fourth embodiment] The fourth embodiment will be described with reference to Fig. 5. A fluidic device 10C of the fourth embodiment includes an ultrasonic wave transmitting section 60C that is arranged differently from that of the first embodiment.

[0050] In this embodiment, the ultrasonic wave transmitting unit 60C is disposed across the inflow channel 20, the separation channel 30 and the first outflow channel 40, as in the first embodiment, and transmits ultrasonic waves to these channels. However, in this embodiment, the wall surfaces 21, 31, 41 of the inflow channel 20, the separation channel 30, and the first outflow channel 40 are formed by a channel member 11, and the ultrasonic transmitter 60C is provided on a wall portion 111 of the channel member 11 that forms the wall surfaces 21, 31, 41. Therefore, the ultrasonic transmitter 60C transmits ultrasonic waves to the inflow channel 20, the separation channel 30, and the first outflow channel 40 via the wall portion 111, and forms standing waves SW1 to SW3 in each channel. In the fluidic device 10C of this embodiment, like the first embodiment, the efficiency of capturing fine particles can be improved.

[0051] Although the ultrasonic wave transmitting unit 60C in the fourth embodiment is configured with one ultrasonic element, it may be configured with a plurality of ultrasonic elements as in the second or third embodiment.

[0052] [Fifth embodiment] The fluidic device of the fifth embodiment basically has the same configuration as the fluidic device 10 of the first embodiment shown in Figure 1, but the material that constitutes the partition 112 between the first outflow flow path 40 and the second outflow flow path 50 is different from that of the first embodiment.

[0053] Specifically, the flow path member 11, except for the partition portion 112, is made of a material capable of reflecting ultrasonic waves in the fluid, similar to the first embodiment. On the other hand, the partition 112 is made of a material that allows the ultrasonic waves in the fluid to pass through (ultrasound-transmitting material). Specific examples of the ultrasound-transmitting material are not particularly limited, but a material with an acoustic impedance close to that of the fluid can be used.

[0054] In this embodiment, the efficiency of capturing fine particles can be improved, similarly to the first embodiment. Furthermore, in this embodiment, standing waves can be stably formed in the first outlet flow path 40 without being limited by the flow path width L3 of the first outlet flow path 40. The fifth embodiment has the same ultrasonic wave transmitting section 60 as the first embodiment, but may have any of the ultrasonic wave transmitting sections 60A to 60C of the second to fourth embodiments.

[0055] [Variations] The present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifications, improvements, and appropriate combinations of the embodiments within the scope that can achieve the object of the present invention.

[0056] In each of the above embodiments, the ultrasonic transmission unit 60, 60A to 60C has one to three ultrasonic elements, but the present invention is not limited to this, and the ultrasonic transmission unit 60, 60A to 60C may have more ultrasonic elements. For example, in each of the above embodiments, the ultrasonic transmission unit 60, 60A to 60C may have a plurality of ultrasonic elements arranged continuously or intermittently along at least one of the X direction and the Y direction.

[0057] In each of the above embodiments, for the sake of simplicity, the number of nodes of the standing wave formed in the inflow channel 20 is one, but it may be plural.

[0058] In each of the above embodiments, the channel width L2 of the separation channel 30 and the channel width L3 of the first outlet channel 40 are each an integer multiple of the channel width L1 of the inlet channel 20, and the standing waves SW1 to SW3 formed in the inlet channel 20, the separation channel 30, and the first outlet channel 40 have nodes that are located at the same positions in the Z direction, but the present invention is not limited to this. For example, the Z positions of the nodes in each channel may be shifted so that the particles move to the -Z position as they flow between the channels in the X direction.

[0059] In each of the above embodiments, the inlet channel 20, the separation channel 30, the first outlet channel 40, and the second outlet channel 50 are arranged along the X direction, and the fluid flows along the X direction, but the present invention is not limited to this. For example, the inlet channel 20, the separation channel 30, the first outlet channel 40, and the second outlet channel 50 may each be arranged along a direction intersecting the Z direction (the direction in which standing waves are formed), such as the Y direction, and the fluid may flow along that direction.

[0060] In the second and third embodiments, the frequencies of the ultrasonic waves transmitted by the ultrasonic elements constituting the ultrasonic transmission units 60A, 60B are the same, but the present invention is not limited to this. For example, if the standing waves SW1 to SW3 formed in the inlet flow path 20, the separation flow path 30, and the first outlet flow path 40 have nodes located at the same positions in the Z direction, the ultrasonic elements may transmit ultrasonic waves of the same frequency.

[0061] As a modification of the third embodiment, the wall surfaces 21, 31, 41 on the -Z side of the inlet channel 20, the separation channel 30, and the first outlet channel 40 may be disposed at different positions in the Z direction. In other words, the first ultrasonic element 63, the second ultrasonic element 64, and the third ultrasonic element 65 may be disposed at different positions in the Z direction.

[0062] The ultrasonic transmitting units 60, 60A to 60C in each of the above embodiments transmit ultrasonic waves to the inlet flow path 20, the separation flow path 30, and the first outlet flow path 40, but the present invention is not limited to this, and ultrasonic waves may be transmitted to either the inlet flow path 20 or the first outlet flow path 40, and the separation flow path 30. For example, in the second embodiment, either the first ultrasonic element 61 or the second ultrasonic element 62 may be omitted, and the wall surface may instead be formed by the flow path member 11. Also, in the third embodiment, either the first ultrasonic element 63 or the third ultrasonic element 65 may be omitted, and the wall surface may instead be formed by the flow path member 11. In these modified examples, the behavior of the microparticles can be controlled either just before the microparticles are trapped by the node of the standing wave SW2 in the separation channel 30, or just after they are released from the node of the standing wave SW2 in the separation channel 30, thereby improving the efficiency of concentrating the microparticles compared to conventional technology. In these modified examples, the width of either the inflow channel 20 or the first outflow channel 40 through which the ultrasonic waves are not transmitted does not have to be an integral multiple of half the wavelength of the ultrasonic waves.

[0063] Summary of this disclosure A fluidic device according to a first aspect of the present disclosure is a fluidic device that separates fine particles in a fluid using ultrasound, and includes an inlet flow path through which a fluid flows, a separation flow path into which the fluid flows from the inlet flow path, a first outlet flow path through which the fluid flows out of the separation flow path, a second outlet flow path through which the fluid flows out of the separation flow path, and an ultrasound transmitting unit that transmits ultrasound to at least one of the inlet flow path or the first outlet flow path and the separation flow path, and forms standing waves along one direction in each flow path through which the ultrasound is transmitted. According to the fluidic device of this embodiment, the behavior of microparticles can be controlled just before they are captured by a node of a standing wave in the separation channel, or just after they are released from a node of a standing wave in the separation channel, thereby improving the efficiency of capturing microparticles.

[0064] In the fluidic device of this embodiment, it is preferable that the flow path width of the inlet flow path in the one direction, the flow path width of the separation flow path, and the flow path width of the first outlet flow path are each an integer multiple of half the wavelength of the ultrasonic wave transmitted from the ultrasonic transmitter. This makes it possible to preferably form standing waves in each of the inflow channel, the separation channel, and the first outflow channel.

[0065] In the fluidic device of this aspect, it is preferable that the channel width of the separation channel and the channel width of the first outlet channel are each an integer multiple of the channel width of the inlet channel. This stabilizes the flow of fine particles from the inflow channel to the first outflow channel, thereby achieving high concentration efficiency.

[0066] In the fluidic device of this aspect, the ultrasonic transmitter may include ultrasonic elements arranged across the inflow channel, the separation channel, and the first outflow channel.

[0067] In the fluidic device of this aspect, the ultrasonic transmission unit may include a plurality of ultrasonic elements. For example, in the fluidic device of this aspect, the ultrasonic transmitting unit may include a first ultrasonic element arranged from the inlet flow path to the separation flow path, and a second ultrasonic element arranged from the separation flow path to the first outlet flow path. Furthermore, in the fluidic device of this aspect, the ultrasonic transmitting unit may include a first ultrasonic element arranged in the inlet flow path, a second ultrasonic element provided in the first outlet flow path, and a third ultrasonic element provided in the separation flow path.

[0068] The fluidic device of this aspect may further include a partition that separates the first outflow channel and the second outflow channel, and the partition may be made of a material that transmits the ultrasonic waves. [Explanation of symbols]

[0069] 10, 10A to 10C...fluidic device, 11...flow path member, 111...wall portion, 112...partition portion, 20...inlet flow path, 21, 22...wall surface, 30...separation flow path, 31, 32...wall surface, 40...first outlet flow path, 41, 42...wall surface, 50...second outlet flow path, 51, 52...wall surface, 60, 60A to 60C...ultrasonic transmitting unit, 61, 63...first ultrasonic element, 62, 64...second ultrasonic element, 65...third ultrasonic element, SW1 to SW3...standing wave.

Claims

1. A fluidic device that separates particles in a fluid using ultrasound, an inlet flow channel through which the fluid flows; a separation channel into which the fluid flows from the inlet channel; a first outlet flow path for causing the fluid to flow out from the separation flow path; a second outlet flow path for causing the fluid to flow out from the separation flow path; A fluidic device comprising: an ultrasonic transmitting unit that transmits ultrasonic waves to at least one of the inlet flow path or the first outlet flow path and the separation flow path, and forms standing waves along one direction in each flow path to which the ultrasonic waves are transmitted.

2. The fluidic device of claim 1, wherein the flow path width of the inlet flow path, the flow path width of the separation flow path, and the flow path width of the first outlet flow path in the one direction are each an integer multiple of half the wavelength of the ultrasonic wave transmitted from the ultrasonic transmitter.

3. The fluidic device according to claim 2 , wherein the channel width of the separation channel and the channel width of the first outlet channel are each an integer multiple of the channel width of the inlet channel.

4. The fluidic device according to claim 2 , wherein the ultrasonic transmitting unit includes ultrasonic elements arranged across the inlet channel, the separation channel, and the first outlet channel.

5. The fluidic device according to claim 2 , wherein the ultrasonic transmitting unit comprises a plurality of ultrasonic elements.

6. The fluidic device according to claim 5 , wherein the ultrasonic transmitting unit comprises a first ultrasonic element arranged from the inlet channel to the separation channel, and a second ultrasonic element arranged from the separation channel to the first outlet channel.

7. The fluidic device according to claim 5, wherein the ultrasonic transmitting unit comprises a first ultrasonic element arranged in the inlet flow path, a second ultrasonic element arranged in the first outlet flow path, and a third ultrasonic element arranged in the separation flow path.

8. a partition portion that separates the first outflow channel and the second outflow channel in the one direction, the ultrasonic wave transmitter transmits the ultrasonic wave to at least the separation channel and the first outflow channel; The fluidic device according to claim 1 , wherein the partition is made of a material that transmits the ultrasonic waves.

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