JP7829237B2 - Fluid purification device - Google Patents

Description

This specification discloses technology relating to fluid purification devices.

Patent Document 1 discloses a technology that uses ultraviolet light emitted from an ultraviolet radiation source to inactivate bacteria, viruses, and other microorganisms attached to microdroplets, aerosols, etc.

Japanese Patent Publication No. 2023-57632

This specification provides novel and useful technologies for purifying fluids.

In a first aspect of the technology disclosed herein, the fluid purification device may include: an inlet into which a fluid flows; an outlet outlet into which a fluid flows; an inlet provided between the inlet and the outlet, the inlet having a discharge section for imparting a positive or negative charge to particles contained in the fluid flowing through the inlet, and a swirling flow generating section for generating a swirling flow; and a collection path provided between the inlet and the outlet, having an electric field generating section, the upstream end of the collection path being connected to the downstream end of the inlet, and the electric field generating section generating an electric field within the collection path, thereby causing an electrostatic force toward the first inner surface of the collection path to act upon the positively or negatively charged particles flowing into the collection path.

According to the above configuration, as the fluid flowing into the inlet passes through the discharge section, the particles in the fluid become positively or negatively charged. Furthermore, as the fluid flowing into the inlet passes through the swirling flow generation section, the fluid becomes a swirling flow after passing through the swirling flow generation section. Therefore, the collection passage receives fluid containing positively or negatively charged particles and flowing as a swirling flow. With this configuration, compared to a configuration where the fluid flows as a straight flow through the collection passage, the distance the fluid travels through the collection passage can be increased. Also, 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. Additionally, 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 for the collection of many particles from the fluid within the collection passage. Therefore, the fluid flowing into the fluid purification device can be purified.

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 generation section may have, in part, a narrowing passage whose 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 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.

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, compared to a configuration where the introduction passage and collection passage extend in the first direction, the above configuration allows for a reduction in the size of the fluid purification device in the first direction.

In a third embodiment, the fluid purification device may further include at least one of the following: a first LED that irradiates ultraviolet light from the first end side in the second direction toward the first inner surface within 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.

The fluid may contain particles such as viruses. According to the above configuration, ultraviolet light emitted from the LED irradiates the viruses and other particles collected on the first inner surface of the collection channel. The viruses and other particles are then inactivated by the ultraviolet light. Therefore, the fluid purification ability of the fluid purification device can be further improved.

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.

The wider the third-direction width at the downstream end of the swirling flow generation section, the smaller the pressure loss. Conversely, the smaller the third-direction width at the downstream end of the swirling flow generation section, the smaller the swirl number, an indicator of the strength of the swirl. When the flow rate injected into the inlet of the fluid purification device is the same, a larger pressure loss requires a larger output from the blower that forces air into the inlet. Conversely, a smaller swirl number reduces the amount of particles collected in the collection passage. With the above configuration, it is possible to ensure a sufficient amount of particles collected in the collection passage without increasing the output of the blower.

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

According to the above configuration, purified air can be discharged through the air curtain.

This is a front view of the air curtain 2 according to the embodiment. This is a front cross-sectional view of the air curtain 2 according to the embodiment. This is an upper cross-sectional view of the right side of the introduction passage 10 according to the embodiment. This figure shows how positive ions PI become charged onto particles PA in the introduction path 10 according to the embodiment. This figure shows how particles PA are collected in the right-side collection path 12 according to the embodiment. This graph shows the relationship between collection efficiency and inflow velocity. A diagram showing the introduction path 100 of an air curtain according to a comparative example. This graph shows the relationship between the ratio and the pressure coefficient. This graph shows the relationship between the ratio and the swirl number.

(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.

The air curtain 2 comprises an inlet passage 10, a right-side collection passage 12, a left-side collection passage 14, and an outlet passage 16. The inlet passage 10 extends in the left-right direction. The inlet passage 10 is located at the bottom of the air curtain 2. The upper right end of the inlet passage 10 is connected to the lower end of the right-side collection passage 12, and the upper left end of the inlet passage 10 is connected to the lower end of the left-side collection passage 14. As shown in Figure 2, an inlet section 10a is formed on the upper surface of the central part of the inlet passage 10. Multiple fans 18 are provided at the top of the inlet passage 10. The right-side collection passage 12 and the left-side collection passage 14 extend in the vertical direction. The outlet passage 16 is located at the top of the air curtain 2. The right end of the outlet passage 16 is connected to the upper end of the right-side collection passage 12, and the left end of the outlet passage 16 is connected to the upper end of the left-side collection passage 14. An outlet section 16a is formed on the lower surface of the discharge passage 16. Although not shown in the illustration, the discharge passage 16 is equipped with a nozzle to direct the fluid discharged from the outlet section 16a downwards.

First, let's briefly explain the fluid flow within the air curtain 2. When the fan 18 is driven, fluid from outside the air curtain 2 flows into the inlet passage 10 via the inlet section 10a. The fluid flowing into the inlet passage 10 then splits into left and right sections, flowing into the right-side collection passage 12 and the left-side collection passage 14. The fluid that has passed through the right-side collection passage 12 and the left-side collection passage 14 flows into the discharge passage 16 and exits downwards from the outlet section 16a. The fluid that exits the discharge passage 16 then flows back into the inlet passage 10 via the inlet section 10a. This creates the wind curtain.

Next, the access path 10 will be described. Note that the access path 10 has a symmetrical shape with respect to its left-right direction. Therefore, in the following description, only the right half of the access path 10 will be described, and the description of the left half will be omitted.

As shown in Figure 3, the introduction channel 10 comprises a straight channel 20 and a swirling flow generation section 22. The straight channel 20 is a flow path with a constant cross-sectional shape and size perpendicular to the left-right direction. The cross-sectional shape of the straight channel 20 is rectangular.

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 surfaces of the front wall 20a and 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 on the front wall 20a and the first negative electrode 32 on the rear wall 20b.

The swirling flow generation unit 22 comprises 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.

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 approaches the upstream direction (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 at the downstream end of the narrowing passage 24 is half the width L2 in the front-rear direction at the upstream end of the narrowing passage 24. The width L1 is preferably between half and one-tenth the width L2.

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 upstream end of the retraction path 24, in the central part in the front-rear direction. 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.

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 illuminates the inner circumferential surface 60a of the electric field generation path 60, which will be described later. In this embodiment, the lower LED 52 is positioned on the upper surface of the lower wall 26b.

Next, the right-side collection path 12 will be described. As shown in Figure 2, the right-side collection path 12 has a shape symmetrical to the left-side collection path 14. Therefore, the right-side collection path 12 will be described below, and the description of the left-side collection path 14 will be omitted.

The right-side collection path 12 includes an electric field generation path 60 and an upper connection path 62. The inner circumferential surface 60a of the electric field generation path 60 has a circular shape. That is, the cross-sectional shape of the electric field generation path 60 perpendicular to the vertical direction is circular. The upstream end of the electric field generation path 60 is connected to the downstream end of the lower connection path 26, and the downstream end of the electric field generation path 60 is connected to the upstream end of the upper connection path 62. The electric field generation 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 generation path 60. The fourth negative electrode 72 is provided along the inner circumferential surface 60a of the electric field generation path 60. That is, in the electric field generation path 60, the third positive electrode discharge wire 70 and the fourth negative electrode 72 are arranged facing 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.

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 circumferential 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 circumferential 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.

(Collection (adsorption) of particles 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 with a plus sign inside the circle.

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.

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. In other words, particle PA becomes positively charged.

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.

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 (specifically, the fourth negative electrode 72 provided on the inner circumferential surface 60a).

Furthermore, 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 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 particles PA in the fluid.

(Comparison of collection efficiency; Figures 6 and 7)
Referring to Figure 6, we will now explain the experimental results comparing the case in which the fluid flows as a swirling flow within the electric field generating path 60 and the case in which 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.

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

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 then collides with the wall defining the lower connecting path 26, changing its path upward. Subsequently, the fluid flows as a straight flow within the electric field generating path 60.

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, by configuring the fluid to flow as a swirling flow within the electric field generating path 60, it is possible to increase the collection efficiency of particles PA and maintain a high collection efficiency of particles PA regardless of the inflow velocity.

(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 in Figure 8 represents the ratio R, and the vertical axis represents the pressure coefficient Cp. The pressure coefficient Cp correlates with pressure loss.

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

The graph in Figure 9 shows the relationship between height z, ratio R, and swirl number S, which represents the strength of the rotation. Height z is the height relative to the lower end of the lower connecting passage 26 (i.e., zero). The horizontal axis in Figure 9 represents height z [mm], and the vertical axis represents the swirl number S. In Figure 9, the swirl number S when ratio R is 1/10 is shown by a solid line, the swirl number S when ratio R is 3/10 is shown by a dashed line, and the swirl number S when ratio R is 1/2 is shown by a dashed line.

As shown in Figure 9, when the ratio R is 1/10, the swirl number S reaches 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 reaches 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 reaches 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.

In Figure 8, the pressure coefficient Cp is preferably smaller than the first pressure coefficient Cp1. This is because it allows the pressure loss to be kept below a predetermined value. Furthermore, in Figure 9, the swirl number S is preferably small when the height z increases. This is to enable the collection of particles in the fluid even at relatively high height z positions. Therefore, in this embodiment, the ratio R is set to 1/2 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 relatively small. Therefore, adopting a ratio R of 1/10 to 1/2 is also conceivable.

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-side 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-side 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-side collection path 12, causing an electrostatic force to act on the positively or negatively charged particles flowing into the right-side collection path 12 in a direction toward the inner circumferential surface 60a ("first inner circumferential surface") of the right-side collection path 12.

According to the above configuration, as the fluid flowing into the introduction passage 10 passes through the upstream discharge section 30, the particles in the fluid become positively charged. Furthermore, as the fluid flowing into the introduction passage 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 passage 12 receives fluid containing positively charged particles and flowing as a swirling flow. This configuration allows the fluid to travel a longer distance within the right-side collection passage 12 compared to a configuration where the fluid flows as a straight flow. Additionally, as the fluid flows as a swirling flow, centrifugal force acts on the particles in a direction that presses them against the inner circumferential surface 60a of the right-side collection passage 12. Furthermore, within the right-side collection passage 12, an electrostatic force acts on the positively charged particles in a direction toward the inner circumferential surface 60a of the right-side collection passage 12. Therefore, many particles are adsorbed onto the inner surface 60a of the right-side collection channel 12. This allows for the collection of many particles from the fluid within the right-side collection channel 12. Consequently, the fluid flowing into the air curtain 2 can be purified.

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") is circular when viewed along the up-down direction. 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.

According to 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 swirls 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-side collection passage 12 extend in the left-right direction.

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

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-side collection channel 12. The viruses and other particles are then inactivated by the ultraviolet light. Therefore, the fluid purification ability of the air curtain 2 can be further improved.

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.

The larger the front-to-back width L1 at the downstream end of the narrowing passage 24, the smaller the pressure loss. Conversely, the smaller the front-to-back width L1 at the downstream end of the narrowing passage 24, the smaller the swirl number S, an indicator of the strength of the swirl. When the flow rate to the fluid purification device is the same, a larger pressure loss requires a larger output from the blower supplying the fluid into the fluid purification device. Conversely, a smaller swirl number S reduces the amount of particles collected in the right-side collection passage 12. With the above configuration, it is possible to ensure a sufficient amount of particles collected in the right-side collection passage 12 without increasing the output of the blower.

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

The above provides a detailed description of specific examples of the technology disclosed herein; however, these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the examples exemplified above. Examples of these modifications are listed below.

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

(Second Modification) The right-side collection path 12 may be inclined at an angle other than 90° relative to the introduction path 10.

(Third Modification) The swirling flow generation unit 22 does not necessarily have a narrowing 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 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.

(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.

(Fifth Modification) The right-side collection path 12 does not necessarily have to include either the lower LED 52 or the upper LED 82.

(Sixth Modification) 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.

(Seventh Modification) Multiple fans may be provided near the outlet 16a of the discharge passage 16 to expel the air from within the air curtain 2 to the outside.

(Eighth Modification) The upstream discharge section 30 and the downstream discharge section 40 may be used to charge the particles in the fluid with a negative charge.

The technical elements described herein or in the drawings demonstrate technical utility individually or in various combinations, and are not limited to the combinations specified 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 utility.

2: Air curtain, 10: Inlet path, 10a: Inflow section, 12: Right side collection path, 14: Left side collection path, 16: Sending path, 16a: Outflow section, 18: Fan, 20: Straight path, 20a: Front wall, 20b: Rear wall, 22: Rotating Circulation generating section, 24: Reduction path, 24a: Front wall, 24b: Rear wall, 24c: Upstream rear wall, 24d: Central rear wall, 24e: Downstream rear wall, 26: Lower connecting path, 26a: Inner peripheral surface, 26b: Lower wall, 30: Upstream discharge section 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 (5)

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. The fluid purification device according to claim 1 , wherein the second direction is a direction perpendicular to the first direction . The fluid purification apparatus 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 within the collection passage, and a second LED that irradiates ultraviolet light from the second side opposite to the first side toward the first inner surface. 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. The fluid purification device is an air curtain, according to any one of claims 1 to 4.