Fluid purification device

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 a technology related to a fluid purification device.

Background Art

[0002] Patent Document 1 discloses a technology that inactivates fungi, viruses, etc. attached to microdroplets, aerosols, etc. by using ultraviolet rays irradiated from an ultraviolet radiation unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] This specification provides a novel and useful technology capable of purifying a fluid.

Means for Solving the Problems

[0005] In a first aspect of the technology disclosed in this specification, a fluid purification device includes an inflow portion into which a fluid flows, an outflow portion from which the fluid flows out, and an introduction path provided between the inflow portion and the outflow portion. The introduction path has a discharge portion that causes particles contained in the fluid flowing through the introduction path to carry a positive or negative charge, and a swirling flow generation portion that generates a swirling flow. The collection path is provided between the introduction path and the outflow portion and has an electric field generation portion. The upstream end of the collection path is connected to the downstream end of the introduction path. The electric field generation portion generates an electric field in the collection path and applies an electrostatic force in a direction toward the first inner peripheral surface of the collection path to the particles carrying the positive or negative charge flowing into the collection path. The fluid purification device may include the collection path.

[0006] According to the above configuration, when the fluid flowing into the inlet passage passes through the discharge section, the particles in the fluid become positively or negatively charged. Furthermore, when the fluid flowing into the inlet passage passes through the swirling flow generation section, the fluid after passing through the swirling flow generation section becomes a swirling flow. Therefore, the fluid flowing into the collection passage contains positively or negatively charged particles and flows as a swirling flow. With this configuration, the distance the fluid flows through the collection passage can be increased compared to a configuration in which the fluid flows as a straight flow. In addition, as the fluid flows as a swirling flow, centrifugal force acts in a direction that presses the particles against the first inner surface of the collection passage. Also, within the collection passage, an electrostatic force acts on the positively or negatively charged particles in a direction toward the first inner surface of the collection passage. As a result, many particles are collected (adsorbed) onto the first inner surface of the collection passage. This allows many particles in the fluid to be collected within the collection passage. Therefore, the fluid flowing into the fluid purification device can be purified.

[0007] In a second embodiment, in the first embodiment, 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, in part, a narrowing passage in which the width in a third direction perpendicular to the first and second directions decreases as it moves upstream, and a connecting passage whose second inner surface, when viewed along the second direction, is circular. The connecting passage may connect the narrowing passage and the collection passage. One of the first surface of the narrowing passage in the third direction and the second surface opposite to the first surface may be connected to the connecting passage along the tangential direction of the second inner surface. The width in the third direction at the downstream end of the narrowing passage may be smaller than the diameter of the second inner surface.

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

[0009] In a third embodiment, the fluid purification device may further include at least one of a first LED that irradiates ultraviolet light from the 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 the second end side opposite to the first end toward the first inner surface.

[0010] The particles contained in the fluid may be viruses, etc. With the above configuration, ultraviolet light emitted from the LED irradiates the viruses, etc. collected on the first inner surface of the collection channel. The viruses, etc. are then inactivated by the ultraviolet light. Therefore, the fluid purification ability of the fluid purification device can be further improved.

[0011] In the fourth embodiment, in the second or third embodiment, the width in the third direction at the downstream end of the narrowing path may be 1 / 2 to 1 / 10 of the width in the third direction at the upstream end of the narrowing path.

[0012] The wider the third-direction width at the downstream end of the swirling flow generation section, the smaller the pressure loss. On the other hand, the smaller the third-direction width at the downstream end of the swirling flow generation section, the smaller the swirl number, which is an indicator of the strength of the swirl. When the flow rate pushed into the introduction passage of the fluid purification device is the same, the greater the pressure loss, the greater the output of the blower that pushes air into the introduction passage needs to be. On the other hand, the smaller the swirl number, the less particles are collected in the collection passage. With the above configuration, it is possible to ensure a sufficient amount of particles are collected in the collection passage without increasing the output of the blower.

[0013] In the fifth embodiment, in any one embodiment of the first to fourth embodiments described above, the fluid purification device may be an air curtain.

[0014] According to the above configuration, purified air can be discharged through the air curtain. [Brief explanation of the drawing]

[0015] [Figure 1] This is a front view of the air curtain 2 according to the embodiment. [Figure 2] This is a front cross-sectional view of the air curtain 2 according to the embodiment. [Figure 3] This is an upper cross-sectional view of the right side of the introduction passage 10 according to the embodiment. [Figure 4] This figure shows how positive ions PI charge particles PA in the introduction path 10 according to the embodiment. [Figure 5] This figure shows how particles PA are collected in the right-side collection path 12 according to the embodiment. [Figure 6] This graph shows the relationship between collection efficiency and inflow velocity. [Figure 7] A diagram showing the introduction path 100 of the air curtain in a comparative example. [Figure 8] This graph shows the relationship between the ratio and the pressure coefficient. [Figure 9] This graph shows the relationship between the ratio and the swirl number. [Modes for carrying out the invention]

[0016] (Examples) The air curtain 2 in Figure 1 is a device that removes viruses, bacteria, fungi, etc. from the fluid (air in this embodiment) flowing into the air curtain 2, purifying the fluid, and then blows out the purified fluid to create a curtain of wind. The air curtain 2 in this embodiment is a tabletop type 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 at the lower part of the air curtain 2. The upper right end of the introduction path 10 is connected to the lower end of the right collection path 12, and the upper left end of the introduction path 10 is connected to the lower end of the left collection path 14. As shown in FIG. 2, an inflow portion 10a is formed on the upper surface of the central portion of the introduction path 10. A plurality of fans 18 are provided at the upper part of the introduction path 10. The right collection path 12 and the left collection path 14 extend in the up-down direction. The delivery path 16 is provided at 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 outflow 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 fluid flow 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 through the inflow portion 10a of the introduction path 10. The fluid flowing into the introduction path 10 is divided in the left-right direction and flows into the right collection path 12 and the left collection path 14. The fluid that has passed through the right collection path 12 and the left collection path 14 flows into the delivery path 16 and flows out downward from the outflow portion 16a of the delivery path 16. Then, the fluid flowing out from the delivery path 16 flows into the introduction path 10 through the inflow portion 10a of the introduction path 10. Thereby, an air curtain is generated.

[0019] Next, the introduction path 10 will be described. The introduction path 10 has a bilaterally symmetric shape centered on the left-right direction of the introduction path 10. Therefore, hereinafter, only the right half of the introduction path 10 will be described, and the description of the left half of the introduction path 10 will be omitted.

[0020] As shown in FIG. 3, the introduction path 10 includes a straight path 20 and a swirling flow generation portion 22. The straight path 20 is a flow path having a constant cross-sectional shape and size perpendicular to the left-right direction. The cross-sectional shape of the straight path 20 is a quadrilateral.

[0021] The straight track 20 is provided with an upstream discharge section 30. The upstream discharge section 30 comprises a first negative electrode 32 and a plurality of first positive electrode 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 track 20. The first positive electrode discharge wires 34 extend in the vertical direction. In the front-rear direction, the first positive electrode discharge wires 34 are provided 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 swirling flow generation unit 22 includes a narrowing path 24 and a lower connecting path 26. The upstream end of the narrowing path 24 is connected to the downstream end of the straight path 20, and the downstream end of the narrowing path 24 is connected to the upstream end of the lower connecting path 26.

[0023] The cross-sectional shape of the narrowing passage 24 perpendicular to the left-right direction is rectangular. The narrowing passage 24 comprises a front wall 24a and a rear wall 24b. The front wall 24a extends along the front-rear direction. The rear wall 24b comprises 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 is directed upstream (i.e., to the right). That is, in the portion where the central rear wall 24d is provided, the width of the narrowing passage 24 in the front-rear direction decreases as it approaches the lower connecting passage 26. In this embodiment, the width L1 in the front-rear direction of the downstream end of the narrowing passage 24 is 1 / 2 of the width L2 in the front-rear direction of the upstream end of the narrowing passage 24. It is preferable that the width L1 be between 1 / 2 and 1 / 10 of the width L2.

[0024] The retraction path 24 is provided with a downstream discharge section 40. The downstream discharge section 40 comprises a second negative electrode 42, a third negative electrode 44, and a plurality of second positive electrode 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 retraction path 24. The third negative electrode 44 is provided at the central part in the front-rear direction at the upstream end of the retraction path 24. The third negative electrode 44 has a shape that curves forward as it moves to the right. The second positive electrode discharge wires 46 extend in the vertical direction. At the upstream end of the retraction path 24, the second positive electrode discharge wires 46 are 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 narrowing path 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 cross-sectional shape of the lower connecting passage 26 perpendicular to the vertical direction is circular. 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 retraction passage 24 is connected to the upstream end of the lower connecting passage 26. Specifically, the front wall 24a of the retraction 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 Figure 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 the lower wall 26b that defines the lower connecting passage 26. The lower wall 26b has a circular shape. The lower support portion 50 is provided in the center of the lower wall 26b. The lower LED 52 is positioned so that the ultraviolet light emitted from the lower LED 52 irradiates the inner surface 60a of the electric field generation path 60, which will be described later. In this embodiment, the lower LED 52 is located on the upper surface of the lower wall 26b.

[0026] Next, the right-side collection path 12 will be described. As shown in Figure 2, the right-side collection path 12 has a shape that is symmetrical to the left-side collection path 14. For this reason, the right-side collection path 12 will be described below, and the description of the left-side collection path 14 will be omitted.

[0027] The right-side collection path 12 includes an electric field generating path 60 and an upper connecting path 62. The inner circumferential surface 60a of the electric field generating path 60 is circular. That is, the cross-sectional shape of the electric field generating path 60 perpendicular to the vertical direction is circular. 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 arranged along the central axis C of the electric field generating path 60. The fourth negative electrode 72 is provided 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 arranged opposite each other. When a voltage is applied to the third positive electrode discharge wire 70, an electric field is generated within the electric field generation path 60.

[0028] The upper connecting path 62 connects the downstream end of the electric field generating path 60 to the upstream end of the discharge path 16. The inner surface of the upper connecting path 62 is circular. That is, the cross-sectional shape of the upper connecting path 62 perpendicular to the vertical direction is circular. The upper connecting 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 connecting path 62. The third positive electrode discharge wire 70 is held vertically between the lower support portion 50 and the upper support portion 80. The upper wall 62a is circular. The upper support portion 80 is provided in the center of the upper wall 62a. The upper LED 82 is positioned so that ultraviolet light emitted from the upper LED 82 irradiates the inner surface 60a of the electric field generating path 60. In this embodiment, the upper LED 82 is positioned on the lower surface of the upper wall 62a.

[0029] (Particle collection (adsorption) by air curtain 2) Referring to Figures 4 and 5, we will explain how the fluid is purified by the air curtain 2. In Figures 4 and 5, for ease of understanding, particles PA in the fluid are shown as white circles, and positive ions PI are shown as circles with a plus sign inside.

[0030] First, when the power to the air curtain 2 in Figure 2 is turned on, the fan 18 is driven. This causes the fluid outside the air curtain 2 to flow into the inlet passage 10 through the inlet section 10a of the inlet passage 10.

[0031] Furthermore, as shown in Figure 4, when the power to 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 to occur between the first negative electrode 32 and the first positive electrode discharge wire 34, generating positive ions PI. In this situation, as the fluid flowing into the introduction path 10 passes between the first negative electrode 32 and the first positive electrode discharge wire 34, the particles PA in the fluid become 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. Therefore, as the fluid passes through the upstream discharge section 30 in the straight path 20 and the downstream discharge section 40 in the narrowing path 24, the particles PA in the fluid become charged with positive ions PI. That is, the particles PA become positively charged.

[0032] The fluid that has passed through the narrowing passage 24 then flows into the lower connecting passage 26. As described above, the front wall 24a of the narrowing 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 Figure 5, the fluid that flows 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] Furthermore, when the power to 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 voltages applied to the first positive electrode discharge wire 34 and the second positive electrode discharge wire 46. Therefore, although corona discharge does not occur in the electric field generation path 60 of the right-side collection path 12, an electric field is generated. When positively charged particles PA flow into the electric field generation path 60, an electrostatic force acts radially outward on the particles PA (i.e., toward the inner surface 60a of the electric field generation path 60). In addition, as the fluid flows through the electric field generation path 60 as a swirling flow, a centrifugal force acts in the direction that pushes the particles PA against the inner surface 60a. Therefore, as the fluid flows as a swirling flow within the right-side collection channel 12, many particles PA in the fluid are collected (adsorbed) onto the inner circumferential surface 60a of the electric field generation channel 60 (more specifically, the fourth negative electrode 72 provided on the inner circumferential surface 60a).

[0034] Furthermore, the particles PA adsorbed on the inner surface 60a of the electric field generation path 60 are irradiated with ultraviolet light from the lower LED 52 and the upper LED 82. Therefore, if the particles PA are viruses or the like, they are inactivated. In this way, within the air curtain 2, the fluid is purified by the collection and inactivation of the particles PA in the fluid.

[0035] (Comparison of collection rates; Figures 6 and 7) Referring to Figure 6, we will now explain the experimental results comparing the case where the fluid flows as a swirling flow within the electric field generating path 60 and the case where the fluid flows as a straight flow along the central axis C within the electric field generating path 60. The vertical axis of Figure 6 shows the collection efficiency [%] of particles PA collected within the electric field generating path 60, and the horizontal axis of Figure 6 shows the inflow velocity [m / s] of the fluid flowing into the introduction path 10. The solid line in Figure 6 shows the collection efficiency when the fluid flows as a swirling flow within the electric field generating path 60, and the dashed line in Figure 6 shows the collection efficiency when the fluid flows as a straight flow within the electric field generating path 60.

[0036] First, referring to Figure 7, the configuration of the introduction path 100 in the comparative example, where the fluid flows as a straight flow through the electric field generation path 60, will be described. Note that components common to the introduction path 100 in the comparative example and the introduction path 10 in this embodiment are denoted by the same reference numerals and their descriptions are omitted.

[0037] As shown in Figure 7, the comparative example's introduction path 100 differs from the introduction path 10 of this embodiment in that it does not have a narrowing path 24. In the comparative example's introduction path 100, the downstream end of the straight path 120 is connected to the upstream end of the lower connecting path 26. In this configuration, the fluid flowing from the straight path 120 into the lower connecting path 26 does not become a swirling flow. The air flowing into the lower connecting path 26 collides with the wall defining the lower connecting path 26, causing its path to change upward. After that, the fluid flows through the electric field generating path 60 as a straight flow.

[0038] As shown in Figure 6, when the fluid flows as a straight flow within the electric field generating path 60, the collection efficiency is 90% or less. Furthermore, when the fluid flows as a straight flow within the electric field generating path 60, the collection efficiency decreases as the inflow velocity increases. On the other hand, when the fluid flows as a swirling flow within the electric field generating path 60, the collection efficiency is approximately 100%. Moreover, the collection efficiency when the fluid flows as a swirling flow within the electric field generating path 60 remains constant regardless of the inflow velocity. Thus, it can be seen that by configuring the fluid to flow as a swirling flow within the electric field generating path 60, the collection efficiency of particle PA can be increased, and the collection efficiency of particle PA can be maintained at a high value regardless of the inflow velocity.

[0039] (Method for setting the ratio R(L1 / L2) in the narrowing path 24; Figures 8 and 9) Referring to Figures 8 and 9, the ratio R(L1 / L2) in the narrowing passage 24 will be explained. The ratio R is the ratio of the width L1 in the longitudinal direction at the downstream end of the narrowing passage 24 to the width L2 in the longitudinal direction at the upstream end of the narrowing passage 24. The graph in Figure 8 shows the relationship between the ratio R and pressure loss. The horizontal axis of Figure 8 represents the ratio R, and the vertical axis represents the pressure coefficient Cp. The pressure coefficient Cp correlates with pressure loss.

[0040] As shown in Figure 8, the pressure coefficient Cp becomes the first pressure coefficient Cp1 when the ratio R is 1 / 10. Then, as the ratio R becomes less than 1 / 10, the pressure coefficient Cp increases, and as the ratio R becomes greater than 1 / 10, the pressure coefficient Cp decreases. Even when the ratio R is greater than 1 / 2, the pressure coefficient Cp decreases gradually.

[0041] The graph in Figure 9 shows the relationship between height z, ratio R, and swirl number S, which represents the strength of the turn. Height z is the height relative to the lower end of the lower connecting passage 26 (i.e., zero). The horizontal axis of Figure 9 shows height z [mm], and the vertical axis shows the swirl number S. In Figure 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 Figure 9, when the ratio R is 1 / 10, the swirl number S is at its maximum, the first swirl number S1, at height z1, and then gradually decreases as the height z increases. When the ratio R is 3 / 10, the swirl number S is at its maximum, the second swirl number S2, at height z2, and then gradually decreases as the height z increases. The second swirl number S2 is smaller than the first swirl number S1. Furthermore, when the ratio R is 1 / 2, the swirl number S is at its third swirl number S3 at height z3, and then 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] In Figure 8, it is desirable that the pressure coefficient Cp be smaller than the first pressure coefficient Cp1. This is because it allows the pressure loss to be kept below a predetermined value. Also, in Figure 9, it is desirable that the swirl number S has a small attenuation when the height z is high. This is to allow particles in the fluid to be collected even at relatively high height z positions. For this reason, in this embodiment, the ratio R is set to 1 / 2 in order to achieve a balance between the pressure coefficient Cp and the swirl number S. Note that if the ratio R is within the range of 1 / 10 to 1 / 2, the pressure coefficient Cp will be 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 purification device") includes an inlet 10a into which fluid flows, an outlet 16a into which fluid flows, and an introduction passage 10 provided between the inlet 10a and the outlet 16a, the introduction passage 10 having an upstream discharge section 30 (an example of a "discharge section") that imparts 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 provided between the introduction passage 10 and the outlet 16a, Furthermore, the right collection path 12 (an example of a "collection path") has an electric field generating path 60 (an example of an "electric field generating section"), the upstream end of the right collection path 12 (an example of a "collection path") is connected to the downstream end of the introduction path 10, and the electric field generating path 60 generates an electric field within the right collection path 12, causing an electrostatic force to act on the positively or negatively charged particles flowing into the right collection path 12 in a direction toward the inner surface 60a ("first inner surface") of the right collection path 12.

[0045] According to the above configuration, as the fluid flowing into the introduction channel 10 passes through the upstream discharge section 30, the particles in the fluid become positively charged. Furthermore, as the fluid flowing into the introduction channel 10 passes through the swirling flow generation section 22, the fluid after passing through the swirling flow generation section 22 becomes a swirling flow. Therefore, the right-side collection channel 12 receives fluid containing positively charged particles and flowing as a swirling flow. With this configuration, compared to a configuration in which the fluid flows as a straight flow through the right-side collection channel 12, the distance the fluid travels through the right-side collection channel 12 can be increased. In addition, as the fluid flows as a swirling flow, centrifugal force acts in a direction that presses the particles against the inner surface 60a of the right-side collection channel 12. Also, within the right-side collection channel 12, an electrostatic force acts on the positively charged particles in a direction toward the inner surface 60a of the right-side collection channel 12. As a result, many particles are adsorbed onto the inner surface 60a of the right-side collection channel 12. This allows many particles in the fluid to be collected within the right-side collection channel 12. Consequently, 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-side collection passage 12 extends along the up-down direction (an example of the "second direction"). The swirling flow generation section 22 includes, in part, a narrowing passage 24 whose width in the front-rear direction ("third direction") decreases as it moves upstream, and a lower connecting passage 26 (an example of the "connecting passage") whose inner circumferential surface 26a (an example of the "first inner circumferential surface") when viewed along the up-down direction is circular. The lower connecting passage 26 connects the narrowing passage 24 and the right-side collection passage 12. The rear surface (an example of the "first surface") of the front wall 24a of the narrowing passage 24 is connected to the lower connecting passage 26 along the tangential direction of the inner circumferential surface 26a. The front-rear width L1 at the downstream end of the narrowing passage 24 is smaller than the diameter of the inner circumferential surface 26a.

[0047] With the above configuration, the fluid flowing into the lower connecting passage 26 does not collide with the inner circumferential surface 26a of the lower connecting passage 26, but instead swirls along the inner circumferential surface 26a of the lower connecting passage 26. Therefore, a fluid flow that flows as a swirling flow can be generated with a simple configuration. Furthermore, with 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-side 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 a "first side") toward the inner circumferential surface 60a (an example of a "second inner circumferential 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 a "second side") toward the inner circumferential surface 60a.

[0049] The fluid may contain particles such as viruses. With the above configuration, ultraviolet light emitted from the lower LED 52 and the upper LED 82 irradiates the viruses and other particles collected on the inner surface 60a of the right collection passage 12. The viruses and other particles are then inactivated by the ultraviolet light. Therefore, the ability of the air curtain 2 to purify the fluid can be further improved.

[0050] In one or more embodiments, the longitudinal width L2 at the downstream end of the narrowing path 24 is 1 / 2 to 1 / 10 of the longitudinal width L1 at the upstream end of the narrowing path 24.

[0051] The larger the front-to-back width L1 at the downstream end of the narrowing passage 24, the smaller the pressure loss. On the other hand, the smaller the front-to-back width L1 at the downstream end of the narrowing passage 24, the smaller the swirl number S, which is an indicator of the strength of the swirl. When the flow rate delivered to the fluid purification device is the same, the larger the pressure loss, the greater the need to increase the output of the blower that delivers the fluid into the fluid purification device. On the other hand, the smaller the swirl number S, the smaller the amount of particles collected in the right-side collection passage 12. With the above configuration, it is possible to ensure the amount of particles collected in the right-side collection passage 12 without increasing the output of the blower.

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

[0053] The specific examples of the technology disclosed herein have been described in detail above, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples described above. The following are some examples of modifications.

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

[0055] (Second modified example) The right-side collection path 12 may be inclined at an angle other than 90° with respect to the introduction path 10.

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

[0057] (Fourth modified example) 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 modified example) The right-side collection path 12 does not need to be equipped with either the lower LED 52 or the upper LED 82.

[0059] (Sixth variation) The width L2 in the longitudinal direction at the downstream end of the narrowing path 24 may be less than 1 / 10 of the width L1 in the longitudinal direction at the upstream end of the narrowing path 24, or greater than 1 / 2 of it.

[0060] (Seventh modified example) Multiple fans may be provided near the outlet 16a of the discharge passage 16 to discharge the air inside the air curtain 2 to the outside.

[0061] (Variation 8) The upstream discharge section 30 and the downstream discharge section 40 may cause the particles in the fluid to be negatively charged.

[0062] The technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated herein or in the drawings can achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [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 Part, 32: First negative electrode, 34: First positive electrode discharge wire, 40: Downstream discharge section, 42: Second negative electrode, 44: Third negative electrode, 46: Second positive electrode discharge wire, 50: Lower support section, 52: Lower LED, 60: Electric field generation path, 60a: Inner surface, 62: Upper connection path, 62a: Upper wall, 70: Third positive electrode discharge wire, 72: Fourth negative electrode, 80: Upper support section, 82: Upper LED, 100: Introduction path, 120: Straight path, C: Central axis

Claims

1. A fluid purification device, The inlet into which the fluid flows, The outlet from which the fluid flows out, An introduction passage provided between the inlet and the outlet, the introduction passage having a discharge section that causes particles contained in the fluid flowing through the introduction passage to be charged with a positive or negative charge, and a swirling flow generating section that generates a swirling flow, A collection path provided between the introduction path and the outflow section, and having an electric field generating section, The upstream end of the collection path is connected to the downstream end of the introduction path. The electric field generating unit generates an electric field within the collection path and applies an electrostatic force to the positively or negatively charged particles flowing into the collection path in a direction toward the first inner surface of the collection path. The collection path is provided, The aforementioned access path extends along the first direction, The collection path extends along a second direction that is inclined with respect to the first direction, The swirling flow generation unit has, in part, a narrowing path in which the width in a third direction perpendicular to the first and second directions decreases as it moves upstream, and a connecting path in which the second inner surface when viewed along the second direction is circular. The aforementioned connecting path connects the aforementioned reduction path and the aforementioned collection path. One of the first surface of the narrowing path in the third direction and the second surface opposite to the first surface is connected to the connecting path along the tangential direction of the second inner surface. The width in the third direction at the downstream end of the narrowing path is smaller than the diameter of the second inner surface. Fluid purification device.

2. The fluid purification device according to claim 1, wherein the second direction is a direction perpendicular to the first direction.

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

4. The fluid purification device according to claim 2, wherein the width in the third direction at the downstream end of the narrowing passage is 1 / 2 to 1 / 10 of the width in the third direction at the upstream end of the narrowing passage.

5. The fluid purification device according to any one of claims 1 to 4, wherein the fluid purification device is an air curtain.

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