Fluid purifier

Abstract

To provide a novel and useful technology capable of purifying fluid.SOLUTION: A fluid purifier includes: an inflow part in which fluid flows; an outflow part from which fluid flows out; an introduction passage which is provided between the inflow part and the outflow part and has a discharge part that charges particles contained in the fluid flowing in the introduction passage with plus or minus electric charges and a rotating flow generating part that generates a rotating flow; a collecting passage which is provided between the introduction passage and the outflow part, and has an electric field generating part, an upstream end of the collecting passage being connected to a downstream end of the introduction passage, the electric field generating part generating an electric field in the collecting passage, and an electrostatic force in the direction heading for a first inner peripheral surface of the collecting passage acting on particles charged with the plus or minus electric charge flown into the collecting passage.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] This specification discloses technology relating to a fluid purifying device. [Background technology]

[0002] Patent Document 1 discloses a technique for inactivating bacteria, viruses, and the like attached to microdroplets, aerosols, and the like, by utilizing ultraviolet light irradiated from an ultraviolet emitting unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2023-57632 A Summary of the Invention [Problem to be solved by the invention]

[0004] Provided herein is a new and useful technique that can purify fluids. [Means for solving the problem]

[0005] In a first aspect of the technology disclosed in this specification, a fluid purifying device may include an inlet section into which a fluid flows, an outlet section from which the fluid flows out, an inlet passage provided between the inlet section and the outlet section, the inlet passage having a discharge section that charges particles contained in the fluid flowing through the inlet passage with a positive or negative electric charge, and a swirling flow generating section that generates a swirling flow, and a collection passage provided between the inlet passage and the outlet section and having an electric field generating section, the upstream end of the collection passage being connected to a downstream end of the inlet passage, the electric field generating section generating an electric field within the collection passage to apply an electrostatic force to the positively or negatively charged particles flowing into the collection passage in a direction toward a first inner circumferential surface of the collection passage.

[0006] According to the above configuration, the fluid that has flowed into the introduction passage passes through the discharge unit, so that the particles in the fluid are positively or negatively charged. Furthermore, the fluid that has flowed into the introduction passage passes through the swirling flow generating unit, so that the fluid becomes a swirling flow after passing through the swirling flow generating unit. Therefore, the fluid that contains particles that are positively or negatively charged and flows as a swirling flow flows into the collection passage. According to this configuration, the distance that the fluid flows in the collection passage can be made longer than in a configuration in which the fluid flows in the collection passage as a straight flow. Furthermore, the fluid flows as a swirling flow, so that a centrifugal force acts in a direction that presses the particles against the first inner circumferential surface of the collection passage. Furthermore, in the collection passage, an electrostatic force acts on the particles that are positively or negatively charged in a direction toward the first inner circumferential surface of the collection passage. Therefore, many particles are collected (adsorbed) on the first inner circumferential surface of the collection passage. As a result, many particles in the fluid can be collected in the collection passage. Therefore, the fluid that flows into the fluid purifying device can be purified.

[0007] In a second aspect, in the first aspect, the introduction passage may extend along a first direction, and the collection passage may extend in a second direction perpendicular to the first direction. The swirling flow generating section may have a reduction passage whose width in a third direction, which is a direction perpendicular to the first direction and the second direction, decreases toward the upstream side, and a connection passage whose second inner circumferential surface when viewed along the second direction is circular. The connection passage may connect the reduction passage and the collection passage. One of the first surface in the third direction of the reduction passage and the second surface opposite to the first surface may be connected to the connection passage along a tangential direction of the second inner circumferential surface. The size of the width in the third direction at the downstream end of the reduction passage may be smaller than the diameter of the second inner circumferential surface.

[0008] According to the above configuration, the fluid flowing into the connecting passage swirls along the second inner circumferential surface of the connecting passage without colliding with the second inner circumferential surface of the connecting passage. Therefore, a swirling flow of fluid can be generated with a simple configuration. Furthermore, according to the above configuration, the size of the fluid purifying device in the first direction can be reduced compared to a configuration in which the introduction passage and the collection passage extend in the first direction.

[0009] In a third aspect, in the second aspect described above, the fluid purification device may further include at least one of a first LED that irradiates ultraviolet light from a first end side in the second direction toward the first inner surface in the collection passage, and a second LED that irradiates ultraviolet light from a second end side opposite the first end toward the first inner surface.

[0010] The particles contained in the fluid may be viruses or the like. According to the above configuration, the ultraviolet light emitted from the LED is irradiated onto the viruses or the like collected on the first inner circumferential surface of the collection path. The viruses or the like are then inactivated by the ultraviolet light. This can further improve the ability of the fluid purifying device to purify the fluid.

[0011] In a fourth aspect, in the second or third aspect, a width in the third direction at a downstream end of the narrowed passage may be 1 / 2 to 1 / 10 of a width in the third direction at an upstream end of the narrowed passage.

[0012] The greater the width in the third direction at the downstream end of the swirling flow generating section, the smaller the pressure loss. On the other hand, the smaller the width in the third direction at the downstream end of the swirling flow generating section, the smaller the swirl number, which is an index of the strength of the swirl, can be. For the same flow rate forced into the inlet passage of the fluid purifying device, the greater the pressure loss, the greater the output of the blower that forces air into the inlet passage must be. On the other hand, the smaller the swirl number, the smaller the amount of particles captured in the collection passage. With the above configuration, it is possible to ensure the amount of particles captured in the collection passage without increasing the output of the blower.

[0013] In a fifth aspect, in any one of the first to fourth aspects, the fluid purifying device may be an air curtain.

[0014] According to the above configuration, purified air can be discharged from the air curtain. [Brief description of the drawings]

[0015] [Figure 1] FIG. 2 is a front view of the air curtain 2 according to the embodiment. [Diagram 2] FIG. 2 is a front cross-sectional view of the air curtain 2 according to the embodiment. [Diagram 3] 2 is a top cross-sectional view of the right side of an introduction passage 10 according to the embodiment. FIG. [Figure 4] 1 is a diagram showing how particles PA are charged with positive ions PI in an introduction path 10 according to the embodiment. FIG. [Diagram 5] 11 is a diagram showing how particles PA are collected in a right-side collection passage 12 according to the embodiment. FIG. [Figure 6] 1 is a graph showing the relationship between collection efficiency and inflow velocity. [Figure 7] FIG. 2 is a diagram showing an introduction path 100 of an air curtain according to a comparative example. [Figure 8] 13 is a graph showing the relationship between the ratio and the pressure coefficient. [Figure 9] 13 is a graph showing the relationship between the ratio and the swirl number. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] (Example) The air curtain 2 in Fig. 1 is a device that purifies the fluid (air in this embodiment) by removing viruses, bacteria, fungi, etc. from the fluid that flows into the air curtain 2, and also sprays the purified fluid to generate a wind curtain. The air curtain 2 in this embodiment is a tabletop device.

[0017] The air curtain 2 includes an introduction path 10, a right collection path 12, a left collection path 14, and a delivery path 16. The introduction path 10 extends in the left-right direction. The introduction path 10 is provided in the lower part of the air curtain 2. The upper end of the right side of the introduction path 10 is connected to the lower end of the right collection path 12, and the upper end of the left side of the introduction path 10 is connected to the lower end of the left collection path 14. As shown in FIG. 2, an inlet portion 10a is formed on the upper surface of the center part of the introduction path 10. A plurality of fans 18 are provided in the upper part of the introduction path 10. The right collection path 12 and the left collection path 14 extend in the vertical direction. The delivery path 16 is provided in the upper part of the air curtain 2. The right end of the delivery path 16 is connected to the upper end of the right collection path 12, and the left end of the delivery path 16 is connected to the upper end of the left collection path 14. An outlet portion 16a is formed on the lower surface of the delivery path 16. Although not shown, the delivery path 16 is provided with a nozzle for directing the fluid flowing out from the outflow portion 16a downward.

[0018] First, an outline of the flow of fluid in the air curtain 2 will be described. When the fan 18 is driven, the fluid outside the air curtain 2 flows into the introduction path 10 via the inlet portion 10a of the introduction path 10. The fluid that flows into the introduction path 10 is divided into the left and right directions and flows into the right collection path 12 and the left collection path 14. The fluid that passes through the right collection path 12 and the left collection path 14 flows into the delivery path 16 and flows downward from the outlet portion 16a of the delivery path 16. Then, the fluid that flows out of the delivery path 16 flows into the introduction path 10 via the inlet portion 10a of the introduction path 10. This generates a wind curtain.

[0019] Next, the introduction path 10 will be described. The introduction path 10 has a shape that is symmetrical about the left-right direction of the introduction path 10. Therefore, only the right half of the introduction path 10 will be described below, and a description of the left half of the introduction path 10 will be omitted.

[0020] 3, the introduction path 10 includes a straight path 20 and a swirl flow generating section 22. The straight path 20 is a flow path having a constant cross-sectional shape perpendicular to the left-right direction and a constant size. The cross-sectional shape of the straight path 20 is a rectangle.

[0021] The straight path 20 is provided with an upstream discharge section 30. The upstream discharge section 30 includes a first negative electrode 32 and a plurality of first positive discharge wires 34. The first negative electrode 32 is provided on the inner circumferential surface of the front wall 20a and the inner circumferential surface of the rear wall 20b that define the straight path 20. The first positive discharge wire 34 extends in the up-down direction. The first positive discharge wire 34 is provided in the front-rear direction between the first negative electrode 32 provided on the front wall 20a and the first negative electrode 32 provided on the rear wall 20b.

[0022] The swirl flow generating section 22 includes a reduction passage 24 and a lower connecting passage 26. The upstream end of the reduction passage 24 is connected to the downstream end of the straight passage 20, and the downstream end of the reduction passage 24 is connected to the upstream end of the lower connecting passage 26.

[0023] The shape of the cross section of the reduction passage 24 perpendicular to the left-right direction is a rectangle. The reduction passage 24 includes a front wall 24a and a rear wall 24b. The front wall 24a extends along the front-rear direction. The rear wall 24b includes an upstream rear wall 24c, a central rear wall 24d, and a downstream rear wall 24e. The upstream rear wall 24c and the downstream rear wall 24e extend along the front-rear direction. The central rear wall 24d curves forward as it moves upstream (i.e., to the right). That is, in the portion where the central rear wall 24d is provided, the front-rear width of the reduction passage 24 becomes smaller as it approaches the lower connecting passage 26. In this embodiment, the front-rear width L1 of the downstream end of the reduction passage 24 is 1 / 2 of the front-rear width L2 of the upstream end of the reduction passage 24. The width L1 may be 1 / 2 to 1 / 10 of the width L2.

[0024] The reduced passage 24 is provided with a downstream discharge section 40. The downstream discharge section 40 includes a second negative electrode 42, a third negative electrode 44, and a plurality of second positive discharge wires 46. The second negative electrode 42 is provided on the inner circumferential surface of the front wall 24a and the inner circumferential surface of the rear wall 24b of the reduced passage 24. The third negative electrode 44 is provided in the center in the front-rear direction at the upstream end of the reduced passage 24. The third negative electrode 44 has a shape that curves forward as it moves to the right. The second positive discharge wire 46 extends in the up-down direction. At the upstream end of the reduced passage 24, the second positive discharge wire 46 is provided between the second negative electrode 42 and the third negative electrode 44 provided on the front wall 24a, and between the second negative electrode 42 and the third negative electrode 44 provided on the rear wall 24b. The second positive electrode discharge wire 46 is further provided at the downstream end of the reduced passage 24, between the second negative electrode 42 provided on the front wall 24a and the second negative electrode 42 provided on the rear wall 24b.

[0025] The inner circumferential surface 26a of the lower connecting passage 26 has a circular shape. That is, the shape of the cross section of the lower connecting passage 26 perpendicular to the up-down direction is a circular shape. The diameter of the inner circumferential surface 26a is the same as the width L2. That is, the diameter of the inner circumferential surface 26a is larger than the width L1. The downstream end of the reduced passage 24 is connected to the upstream end of the lower connecting passage 26. Specifically, the front wall 24a of the reduced passage 24 is connected to the lower connecting passage 26 along the tangential direction of the inner circumferential surface 26a of the lower connecting passage 26. As shown in FIG. 2, the downstream end of the lower connecting passage 26 is connected to the upstream end of the right collection passage 12. The lower connecting passage 26 is provided with a lower support portion 50 and a lower LED 52. The lower support portion 50 extends upward from a lower wall 26b that defines the lower connecting passage 26. The lower wall 26b has a circular shape. The lower support part 50 is provided in the center of the lower wall 26b. The lower LED 52 is disposed at a position where the ultraviolet light emitted from the lower LED 52 is irradiated onto an inner circumferential surface 60a of an electric field generating path 60 described later. In this embodiment, the lower LED 52 is disposed on the upper surface of the lower wall 26b.

[0026] Next, the right-side collection passage 12 will be described. As shown in Fig. 2, the right-side collection passage 12 has a shape symmetrical with respect to the left-side collection passage 14. Therefore, in the following, the right-side collection passage 12 will be described, and a description of the left-side collection passage 14 will be omitted.

[0027] The right collection path 12 includes an electric field generating path 60 and an upper connecting path 62. An inner circumferential surface 60a of the electric field generating path 60 has a circular shape. That is, the shape of a cross section of the electric field generating path 60 perpendicular to the up-down direction is a circular shape. The upstream end of the electric field generating path 60 is connected to the downstream end of the lower connecting path 26, and the downstream end of the electric field generating path 60 is connected to the upstream end of the upper connecting path 62. The electric field generating path 60 is provided with a third positive electrode discharge wire 70 and a fourth negative electrode 72. The third positive electrode discharge wire 70 is disposed along the central axis C of the electric field generating path 60. The fourth negative electrode 72 is disposed along the inner circumferential surface 60a of the electric field generating path 60. That is, in the electric field generating path 60, the third positive electrode discharge wire 70 and the fourth negative electrode 72 are disposed opposite each other. When a voltage is applied to the third positive electrode discharge wire 70 , an electric field is generated in the electric field generating path 60 .

[0028] The upper connection path 62 connects the downstream end of the electric field generating path 60 and the upstream end of the delivery path 16. The inner circumferential surface of the upper connection path 62 has a circular shape. That is, the cross section of the upper connection path 62 perpendicular to the vertical direction has a circular shape. The upper connection path 62 is provided with an upper support portion 80 and an upper LED 82. The upper support portion 80 extends downward from the upper wall 62a that defines the upper connection path 62. The third positive electrode discharge wire 70 is sandwiched in the vertical direction by the lower support portion 50 and the upper support portion 80. The upper wall 62a has a circular shape. The upper support portion 80 is provided in the center of the upper wall 62a. The upper LED 82 is disposed at a position where the ultraviolet light emitted from the upper LED 82 is irradiated onto the inner circumferential surface 60a of the electric field generating path 60. In this embodiment, the upper LED 82 is disposed on the lower surface of the upper wall 62a.

[0029] (Particle collection (adsorption) by air curtain 2) The manner in which the fluid is purified by the air curtain 2 will be described with reference to Figures 4 and 5. For ease of understanding, in Figures 4 and 5, particles PA in the fluid are shown as white circles, and positive ions PI are shown as circles with a plus sign inside.

[0030] 2 is turned on, the fan 18 is driven, causing the fluid outside the air curtain 2 to flow into the introduction path 10 via the inlet portion 10a of the introduction path 10.

[0031] As shown in FIG. 4, when the power supply of the air curtain 2 is turned on, a high voltage is applied to the first positive electrode discharge wire 34 of the upstream discharge section 30 and the second positive electrode discharge wire 46 of the downstream discharge section 40. This causes a corona discharge between the first negative electrode 32 and the first positive electrode discharge wire 34, generating positive ions PI. In this situation, the fluid that has flowed into the introduction path 10 passes between the first negative electrode 32 and the first positive electrode discharge wire 34, and the particles PA in the fluid are charged with positive ions PI. Corona discharge also occurs between the second negative electrode 42 and the second positive electrode discharge wire 46, and between the third negative electrode 44 and the second positive electrode discharge wire 46, generating positive ions PI. For this reason, the particles PA in the fluid are charged with positive ions PI as the fluid passes through the upstream discharge section 30 in the straight path 20 and the downstream discharge section 40 in the reduced path 24. That is, the particles PA are positively charged.

[0032] Then, the fluid that has passed through the reduction passage 24 flows into the lower connecting passage 26. As described above, the front wall 24a of the reduction passage 24 is connected to the lower connecting passage 26 along the tangential direction of the inner circumferential surface 26a of the lower connecting passage 26. In this case, as shown in FIG. 5, the fluid that has flowed into the lower connecting passage 26 becomes a swirling flow that flows along the inner circumferential surface 26a of the lower connecting passage 26.

[0033] When the power supply of the air curtain 2 is turned on, a voltage is applied to the third positive electrode discharge wire 70 in the right-side collection path 12. The voltage applied to the third positive electrode discharge wire 70 is lower than the voltage applied to the first positive electrode discharge wire 34 and the second positive electrode discharge wire 46. Therefore, in the electric field generating path 60 of the right-side collection path 12, no corona discharge occurs, but an electric field is generated. When the positively charged particles PA flow into the electric field generating path 60, an electrostatic force acts on the particles PA in the radially outward direction (i.e., in the direction toward the inner circumferential surface 60a of the electric field generating path 60). In addition, as the fluid flows in the electric field generating path 60 as a swirling flow, a centrifugal force acts in the direction of pressing the particles PA against the inner circumferential surface 60a. As a result, as the fluid flows as a swirling flow within the right-side collection passage 12, many particles PA in the fluid are collected (adsorbed) on the inner surface 60a of the electric field generating passage 60 (more specifically, the fourth negative electrode 72 provided on the inner surface 60a).

[0034] Furthermore, the particles PA adsorbed to the inner circumferential surface 60a of the electric field generating path 60 are irradiated with ultraviolet light emitted from the lower LED 52 and the upper LED 82. Therefore, if the particles PA are viruses or the like, the viruses or the like are inactivated. In this way, the particles PA in the fluid within the air curtain 2 are captured and inactivated, thereby purifying the fluid.

[0035] (Comparison of capture rates: Figures 6 and 7) With reference to Fig. 6, an experimental result comparing a case where the fluid flows as a swirling flow in the electric field generating channel 60 with a case where the fluid flows as a straight flow along the central axis C in the electric field generating channel 60 will be described. The vertical axis of Fig. 6 indicates the collection efficiency [%] of particles PA collected in the electric field generating channel 60, and the horizontal axis of Fig. 6 indicates the inflow velocity [m / s] of the fluid flowing into the introduction channel 10. The solid line in Fig. 6 indicates the collection efficiency when the fluid flows as a swirling flow in the electric field generating channel 60, and the dashed line in Fig. 6 indicates the collection efficiency when the fluid flows as a straight flow in the electric field generating channel 60.

[0036] 7, a description will be given of the configuration of the introduction channel 100 of the comparative example when the fluid flows as a straight flow inside the electric field generating channel 60. Note that components common to the introduction channel 100 of the comparative example and the introduction channel 10 of the present embodiment will be denoted by the same reference numerals and description thereof will be omitted.

[0037] As shown in Fig. 7, the introduction path 100 of the comparative example differs from the introduction path 10 of the present embodiment in that it does not have a reduction path 24. In the introduction path 100 of the comparative example, the downstream end of the straight path 120 is connected to the upstream end of the lower connecting path 26. In such a configuration, the fluid that flows from the straight path 120 into the lower connecting path 26 does not become a swirling flow. Then, the air that flows into the lower connecting path 26 collides with the wall that defines the lower connecting path 26, and its course changes to an upward direction. Thereafter, the fluid flows in the electric field generating path 60 as a straight flow.

[0038] As shown in Fig. 6, when the fluid flows as a straight flow inside the electric field generating channel 60, the collection efficiency is 90% or less. When the fluid flows as a straight flow inside the electric field generating channel 60, the collection efficiency decreases as the inflow speed increases. On the other hand, when the fluid flows as a swirling flow inside the electric field generating channel 60, the collection efficiency is approximately 100%. When the fluid flows as a swirling flow inside the electric field generating channel 60, the collection efficiency is constant regardless of the inflow speed. In this way, it can be seen that by configuring the fluid to flow as a swirling flow inside the electric field generating channel 60, the collection efficiency of the particles PA can be increased and the collection efficiency of the particles PA can be maintained at a high value regardless of the inflow speed.

[0039] (Method of setting the ratio R(L1 / L2) in the narrowing passage 24; Figs. 8 and 9) The ratio R (L1 / L2) in the reduced passage 24 will be described with reference to Figures 8 and 9. The ratio R is the ratio of the width L1 in the front-to-rear direction at the downstream end of the reduced passage 24 to the width L2 in the front-to-rear direction at the upstream end of the reduced passage 24. The graph in Figure 8 shows the relationship between the ratio R and pressure loss. The horizontal axis of Figure 8 shows the ratio R, and the vertical axis shows the pressure coefficient Cp. The pressure coefficient Cp correlates with the pressure loss.

[0040] 8, when the ratio R is 1 / 10, the pressure coefficient Cp becomes a first pressure coefficient Cp1. As the ratio R becomes smaller than 1 / 10, the pressure coefficient Cp becomes larger, and as the ratio R becomes larger than 1 / 10, the pressure coefficient Cp becomes smaller. When the ratio R is larger than 1 / 2, the pressure coefficient Cp also becomes gradually smaller.

[0041] The graph in Fig. 9 shows the relationship between height z, ratio R, and swirl number S, which indicates the strength of the swirl. Height z is the height when the lower end of the lower connecting passage 26 is used as the reference (i.e., zero). The horizontal axis of Fig. 9 shows height z [mm], and the vertical axis of Fig. 9 shows swirl number S. Note that in Fig. 9, the swirl number S when the ratio R is 1 / 10 is shown by a solid line, the swirl number S when the ratio R is 3 / 10 is shown by a dashed line, and the swirl number S when the ratio R is 1 / 2 is shown by a dashed line.

[0042] As shown in FIG. 9, when the ratio R is 1 / 10, the swirl number S is a maximum first swirl number S1 at the position of height z1, and thereafter gradually decreases as the height z increases. When the ratio R is 3 / 10, the swirl number S is a maximum second swirl number S2 at the position of height z2, and thereafter gradually decreases as the height z increases. The second swirl number S2 is smaller than the first swirl number S1. When the ratio R is 1 / 2, the swirl number S is a third swirl number S3 at the position of height z3, and thereafter gradually decreases as the height z increases. The attenuation of the swirl number S when the ratio R is 1 / 2 is smaller than the attenuation of the swirl number S when the ratio R is 1 / 10 and 1 / 5.

[0043] It is desirable that the pressure coefficient Cp in FIG. 8 is smaller than the first pressure coefficient Cp1. This is because the pressure loss can be reduced to a predetermined value or less. It is also desirable that the swirl number S in FIG. 9 is reduced in attenuation when the height z increases. This is to enable particles in the fluid to be collected even at a position where the height z is relatively high. For this reason, in this embodiment, in order to achieve both the pressure coefficient Cp and the swirl number S, the ratio R is set to 1 / 2. Note that, if the ratio R is within a range of 1 / 10 to 1 / 2, the pressure coefficient Cp is lower than the first pressure coefficient Cp1, and the attenuation of the swirl number S can be made relatively small. For this reason, it is also possible to adopt a ratio R of 1 / 10 to 1 / 2.

[0044] In one or more embodiments, the air curtain 2 (an example of a "fluid purifying device") includes an inflow section 10a through which a fluid flows in, an outflow section 16a through which the fluid flows out, an introduction passage 10 provided between the inflow section 10a and the outflow section 16a, the introduction passage 10 having an upstream discharge section 30 (an example of a "discharge section") that applies a positive or negative charge to particles contained in the fluid flowing through the introduction passage 10, and a swirling flow generating section 22 that generates a swirling flow, and the introduction passage 10 is provided between the introduction passage 10 and the outflow section 16a, and a right-side collection path 12 (an example of a "collection path") having an electric field generating path 60 (an example of an "electric field generating section"), the upstream end of the right-side collection path 12 (an example of a "collection path") being connected to the downstream end of the introduction path 10, the electric field generating path 60 generating an electric field within the right-side collection path 12 to apply an electrostatic force to the positively or negatively charged particles flowing into the right-side collection path 12 in a direction toward the inner surface 60a ("first inner surface") of the right-side collection path 12.

[0045] According to the above configuration, the fluid that has flowed into the introduction passage 10 passes through the upstream discharge section 30, so that the particles in the fluid are positively charged. In addition, the fluid that has flowed into the introduction passage 10 passes through the swirling flow generating section 22, so that the fluid after passing through the swirling flow generating section 22 becomes a swirling flow. Therefore, a fluid that contains positively charged particles and flows as a swirling flow flows into the right collection passage 12. According to this configuration, the distance that the fluid flows through the right collection passage 12 can be made longer, compared to a configuration in which the fluid flows through the right collection passage 12 as a straight flow. In addition, as the fluid flows as a swirling flow, a centrifugal force acts in a direction that presses the particles against the inner circumferential surface 60a of the right collection passage 12. In addition, in the right collection passage 12, an electrostatic force acts on the positively charged particles in a direction toward the inner circumferential surface 60a of the right collection passage 12. As a result, many particles are adsorbed to the inner circumferential surface 60a of the right collection passage 12. This allows many particles in the fluid to be collected in the right collection passage 12. Therefore, the fluid flowing into the air curtain 2 can be purified.

[0046] In one or more embodiments, the introduction passage 10 extends along the left-right direction (an example of the "first direction"). The right collection passage 12 extends along the up-down direction (an example of the "second direction"). The swirling flow generating section 22 has a reduction passage 24, a part of which has a width in the front-rear direction (the "third direction") that decreases toward the upstream side, and a lower connecting passage 26 (an example of a "connecting passage") whose inner circumferential surface 26a (an example of a "first inner circumferential surface") when viewed along the up-down direction is circular. The lower connecting passage 26 connects the reduction passage 24 and the right collection passage 12. The rear surface (an example of the "first surface") of the front wall 24a of the reduction passage 24 is connected to the lower connecting passage 26 along the tangent direction of the inner circumferential surface 26a. The width L1 in the front-rear direction at the downstream end of the reduction passage 24 is smaller than the diameter of the inner circumferential surface 26a.

[0047] According to the above configuration, the fluid flowing into the lower connecting passage 26 swirls along the inner circumferential surface 26a of the lower connecting passage 26 without colliding with the inner circumferential surface 26a of the lower connecting passage 26. Therefore, a flow of fluid that flows as a swirling flow can be generated with a simple configuration. Furthermore, according to the above configuration, the size of the air curtain 2 in the left-right direction can be reduced compared to a configuration in which the introduction passage 10 and the right collection passage 12 extend in the left-right direction.

[0048] In one or more embodiments, the air curtain 2 further includes a lower LED 52 (an example of a "first LED") that irradiates ultraviolet light from the lower side (an example of the "first side") toward the inner surface 60a (an example of the "second inner surface") in the right collection passage 12, and an upper LED 82 (an example of a "second LED") that irradiates ultraviolet light from the upper side (an example of the "second side") toward the inner surface 60a.

[0049] The particles contained in the fluid may be viruses or the like. According to the above configuration, the ultraviolet light emitted from the lower LED 52 and the upper LED 82 is irradiated onto the viruses or the like collected on the inner circumferential surface 60a of the right-side collection passage 12. The viruses or the like are then inactivated by the ultraviolet light. This further improves the ability of the air curtain 2 to purify the fluid.

[0050] In one or more embodiments, the width L2 in the front-to-rear direction at the downstream end of the narrowing passage 24 is 1 / 2 to 1 / 10 of the width L1 in the front-to-rear direction at the upstream end of the narrowing passage 24.

[0051] The greater the front-rear width L1 at the downstream end of the reduction passage 24, the smaller the pressure loss. On the other hand, the smaller the front-rear width L1 at the downstream end of the reduction passage 24, the smaller the swirl number S, which is an index of the strength of the swirl, can be. For the same flow rate sent to the fluid purifying device, the greater the pressure loss, the greater the output of the blower that sends the fluid into the fluid purifying device must be. On the other hand, the smaller the swirl number S, the smaller the amount of particles collected in the right collection passage 12. With the above configuration, it is possible to ensure the amount of particles collected in the right collection passage 12 without increasing the output of the blower.

[0052] Furthermore, in the air curtain 2, purified air can be discharged.

[0053] Although specific examples of the technology disclosed in this specification have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. Modifications are listed below.

[0054] (First Modification) The introduction passage 10 and the right collection passage 12 may extend in the same direction (for example, the left-right direction).

[0055] (Second Modification) The right collection passage 12 may be inclined with respect to the introduction passage 10 at an angle other than 90°.

[0056] (Third Modification) The swirling flow generating section 22 does not have to have the reduction passage 24. In this modification, a slit for narrowing the flow path in the front-rear direction may be provided at the downstream end of the introduction passage 10, i.e., at the connection between the introduction passage 10 and the right-side collection passage 12. In another modification, a fixed vane for generating a swirling flow may be provided at the downstream end of the introduction passage 10.

[0057] (Fourth Modification) The lower end of the right-side collection passage 12 may be rounded. In this case, the pressure loss of the air curtain 2 can be reduced.

[0058] (Fifth Modification) The right-side collection passage 12 does not necessarily have to include one of the lower LED 52 and the upper LED 82.

[0059] (Sixth Modification) The width L2 in the front-rear direction of the downstream end of the reduced passage 24 may be smaller than 1 / 10 or larger than 1 / 2 the width L1 in the front-rear direction of the upstream end of the reduced passage 24.

[0060] (Seventh Modification) A plurality of fans may be provided near the outlet portion 16a of the outlet path 16 for discharging the air inside the air curtain 2 to the outside.

[0061] (Eighth Modification) The upstream discharge section 30 and the downstream discharge section 40 may negatively charge particles in the fluid.

[0062] The technical elements described in this specification or drawings have technical utility either alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technologies illustrated in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives is itself technically useful. [Explanation of symbols]

[0063] 2: Air curtain, 10: Inlet path, 10a: Inflow section, 12: Right side collection path, 14: Left side collection path, 16: Outlet path, 16a: Outflow section, 18: Fan, 20: Straight path, 20a: Front wall, 20b: Back wall, 22: Swirling flow generation section, 24: Reduction path, 24a: Front wall, 24b: Rear wall, 24c: Upstream rear wall, 24d: Center rear wall, 24e: Downstream rear wall, 26: Lower connecting path, 26a: Inner peripheral surface, 26b: Lower wall, 30: Upstream discharge portion, 32: first negative electrode, 34: first positive discharge wire, 40: downstream discharge portion, 42: second negative electrode, 44: third negative electrode, 46: second positive discharge wire, 50: lower support portion, 52: lower LED, 60: electric field generating path, 60a: inner circumferential surface, 62: upper connection path, 62a: upper wall, 70: third positive discharge wire, 72: fourth negative electrode, 80: upper support portion, 82: upper LED, 100: introduction path, 120: straight path, C: central axis

Claims

1. A fluid purification device, comprising: an inlet portion into which a fluid flows; an outlet portion through which the fluid flows out; An inlet passage provided between the inflow section and the outflow section, the inlet passage having a discharge section that charges particles contained in the fluid flowing through the inlet passage with a positive or negative electric charge, and a swirling flow generating section that generates a swirling flow; A collection channel provided between the introduction channel and the outflow section and having an electric field generating section, The upstream end of the collection passage is connected to the downstream end of the introduction passage, The electric field generating unit generates an electric field in the collection path, and applies an electrostatic force to the positively or negatively charged particles flowing into the collection path in a direction toward a first inner circumferential surface of the collection path. The collection path, Fluid purification equipment.

2. The introduction path extends along a first direction, The collection path extends along a second direction perpendicular to the first direction, a narrowing passage having a width in a third direction perpendicular to the first direction and the second direction that decreases toward an upstream side; and a connecting passage having a second inner circumferential surface that is circular when viewed along the second direction, the connection passage connects the reduction passage and the collection passage, one of a first surface of the reduction passage in the third direction and a second surface opposite to the first surface is connected to the connection passage along a tangential direction of the second inner circumferential surface, The fluid purifying apparatus according to claim 1 , wherein a width in the third direction of the downstream end of the reduced passage is smaller than a diameter of the second inner circumferential surface.

3. 3. The fluid purifying device according to claim 2, further comprising at least one of a first LED that irradiates ultraviolet light toward the first inner circumferential surface in the collection passage from a first side in the second direction, and a second LED that irradiates ultraviolet light toward the first inner circumferential surface from a second side opposite the first side.

4. 3. The fluid purifying apparatus according to claim 2, wherein a width in the third direction at the downstream end of said reduced passage is 1 / 2 to 1 / 10 of a width in the third direction at the upstream end of said reduced passage.

5. The fluid purifying device according to claim 1 , wherein the fluid purifying device is an air curtain.

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