Sterilization device

Abstract

To provide a sterilization device that can sterilize liquids uniformly and efficiently. [Solution] The sterilization device comprises a dropping section 10 that drops liquid in a film or linear manner, and a light source section 12 that irradiates the dropping liquid with ultraviolet light and has a planar light-emitting surface. The light source section 12 comprises a plurality of ultraviolet light-emitting elements 14 and a diffuser plate 13 that diffuses the ultraviolet light emitted by each element 14 in a planar manner.

Description

Technical Field

[0001] The present invention relates to a sterilization device.

Background Art

[0002] There is known a sterilization device that sterilizes and inactivates bacteria and viruses in a liquid by irradiating ultraviolet light. A mercury lamp is widely used as a light source.

[0003] Patent Document 1 describes a sterilization device that drops a liquid through a slit and irradiates ultraviolet light emitted by a mercury lamp onto the liquid during the fall. According to the sterilization device of Patent Document 1, a liquid with a low transmittance of ultraviolet light can be efficiently sterilized.

[0004] Patent Document 2 describes a sterilization device that drops a liquid linearly and arranges a plurality of light-emitting elements that emit ultraviolet light in the circumferential direction of the falling liquid, and irradiates the liquid with ultraviolet light emitted by the light-emitting elements.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, since the sterilization device of Patent Document 1 uses a mercury lamp, it takes time to light up and it is difficult to control the light amount. In addition, although the mercury lamp can be adjusted by ON / OFF if there are multiple lamps, basically the light amount cannot be adjusted. Further, since the light-emitting element of the sterilization device of Patent Document 2 is a point-like light source, unevenness occurs in the irradiation intensity. Therefore, it has been difficult for the sterilization devices of Patent Documents 1 and 2 to uniformly and efficiently sterilize a liquid with a low transmittance of ultraviolet light.

[0007] This invention was made in view of the above background, and aims to provide a sterilization device that can sterilize liquids uniformly and efficiently. [Means for solving the problem]

[0008] One aspect of the present invention is, A dropping part that drops the liquid in a film or line, The device includes a light source unit that irradiates the falling liquid with ultraviolet light and whose light-emitting surface has a planar shape, The light source unit is a sterilization device having a plurality of ultraviolet light-emitting elements and a diffuser plate that diffuses the ultraviolet light emitted by each of the light-emitting elements in a planar manner. [Effects of the Invention]

[0009] In the above embodiment, ultraviolet light emitted from the light source unit is irradiated onto the liquid falling from the dropping section to sterilize and inactivate the liquid. Here, the light source unit diffuses the ultraviolet light emitted by multiple light-emitting elements using a diffuser plate to create a planar light source. Therefore, ultraviolet light can be irradiated onto the liquid uniformly.

[0010] As described above, according to the above embodiment, a sterilization device capable of uniformly and efficiently sterilizing liquids can be provided. [Brief explanation of the drawing]

[0011] [Figure 1] A cross-sectional view showing the configuration of the sterilization device in Embodiment 1, the view showing the cross-section in the direction of gravity. [Figure 2] A view of the sterilization device in Embodiment 1 from above. [Figure 3] A cross-sectional view showing the configuration of the sterilization device in Embodiment 2, the view showing the cross-section in the direction of gravity. [Figure 4] A view of the sterilization device in Embodiment 2 from above. [Modes for carrying out the invention]

[0012] The sterilization device comprises a dropping section that drops liquid in a film or linear manner, and a light source section that irradiates the dropping liquid with ultraviolet light and has a planar light-emitting surface. The light source section comprises a plurality of ultraviolet light-emitting elements and a diffuser plate that diffuses the ultraviolet light emitted by each element in a planar manner.

[0013] In the above sterilization device, the light intensity of the light-emitting surface of the light source may be controlled to differ in the direction of gravity according to the rate at which the liquid falls. This allows for more uniform sterilization of the liquid. The light intensity of the light-emitting surface of the light source may be made to differ in the direction of gravity by changing the number of light-emitting elements. The light intensity of the light-emitting surface of the light source may be made to differ in the direction of gravity by changing the light intensity of each individual light-emitting element. The light intensity of the light-emitting surface of the light source may be made to differ in the direction of gravity by controlling the current value of the light-emitting elements.

[0014] In the above-described fluid sterilization apparatus, the light intensity of the light-emitting surface of the light source may be made stronger as it moves downward in the direction of gravity. This allows for more efficient sterilization and inactivation of liquids.

[0015] In the above-described fluid sterilization apparatus, the light intensity of the light-emitting surface of the light source may be made stronger as it moves upward in the direction of gravity. This allows for more uniform sterilization and inactivation of the liquid.

[0016] In the above-described sterilization device, the dropping part allows the liquid to fall in a flat film-like manner, and the light source may have a flat light-emitting surface, positioned so that the light-emitting surface is parallel to the liquid surface. This allows for uniform and efficient sterilization of the liquid.

[0017] In the above-described sterilization device, the dropping part may drop the liquid in a linear fashion, and the light source may be positioned so that the light-emitting surface is on the inner circumference of the cylinder, and the liquid line is aligned with the central axis of the cylinder. This allows for uniform and efficient sterilization of the liquid.

[0018] In the above-described sterilization device, the diffusion plate may be made of quartz or a fluororesin. It can efficiently diffuse ultraviolet light.

[0019] In the above-described sterilization device, furthermore, it may have a sensor for measuring the liquid transmittance or flow rate, and based on the transmittance or flow rate measured by the sensor, the on / off or light quantity of each light-emitting element may be adjusted. It can be adjusted to an appropriate light quantity according to the turbidity and flow rate of the liquid.

[0020] (Embodiment 1) FIG. 1 is a diagram showing the configuration of the sterilization device 1 in Embodiment 1, and is a cross-sectional view in the gravitational direction. Also, FIG. 2 is a diagram of the sterilization device 1 in Embodiment 1 as viewed from above. As shown in FIGS. 1 and 2, the sterilization device 1 in Embodiment 1 has a dripping part 10, a light source part 12, and a tray 15.

[0021] The dripping part 10 is a device for dripping the liquid L. The dripping part 10 passes the liquid flowing in from the inlet 16 through the slit 17 and drops it. Here, as shown in FIGS. 1 and 2, the slit 17 is formed linearly with a predetermined width. Therefore, the liquid L drops in a flat film shape. The width of the slit 17 is set so that the liquid L can sufficiently transmit the ultraviolet light emitted by the light source part 12 in a thin film shape. A plurality of inlets 16 are provided. The plurality of inlets 16 are arranged in a row above the slit 17. The arrangement direction thereof is parallel to the linear direction of the slit 17. Thereby, the liquid L flows into the slit 17 evenly.

[0022] The light source unit 12 is a planar light source that irradiates ultraviolet light onto the liquid L dropped from the dropping section 10. Two light source units 12 are arranged facing each other with the liquid L in between. The light source unit 12 has a diffuser plate 13 and a plurality of light-emitting elements 14. The light source unit 12 achieves planar light emission by diffusing the ultraviolet light emitted by the plurality of light-emitting elements 14 with the diffuser plate 13. In Embodiment 1, two light source units 12 are provided to irradiate both sides of the flat, film-like liquid L with ultraviolet light, but only one may be used. Alternatively, one of the two light source units 12 may be replaced with a reflector plate. Since the ultraviolet light that has passed through the liquid L can be reflected by the reflector plate and irradiated back onto the liquid L, the sterilization efficiency can be improved.

[0023] The light-emitting element 14 is a device made of a group III nitride semiconductor that emits ultraviolet light. Its emission wavelength is, for example, 200 to 300 nm, and is particularly preferably 250 to 280 nm. Multiple light-emitting elements 14 are arranged in a planar manner as shown in Figures 1 and 2. The light-emitting elements 14 may be mounted on a submount to constitute a light-emitting device. Alternatively, the light-emitting device may be mounted on a drive circuit board. Alternatively, the light-emitting elements 14 may be directly mounted on the drive circuit board.

[0024] The number and arrangement of the light-emitting elements 14 are arbitrary, as long as they are set so that ultraviolet light is emitted in a planar direction due to scattering of ultraviolet light by the diffuser plate 13. For example, multiple light-emitting elements 14 can be arranged in a triangular lattice pattern or a square lattice pattern when viewed from the horizontal direction.

[0025] The diffuser plate 13 has a flat plate shape. The diffuser plate 13 is made of a material that transmits ultraviolet light. For a diffuser plate that diffuses ultraviolet light, it is important to select a material with a low ultraviolet absorption rate as the constituent material. For example, the light absorption rate of the diffuser plate 13 should be 5% or less. The diffuser plate 13 can be made of materials such as quartz, sapphire, ultraviolet-transmitting glass, acrylic, fluororesins such as PTFE and PFA, etc.

[0026] Generally, a diffuser plate 13 is a component that diffuses light by creating minute irregularities or small curves at the interface formed by materials with different refractive indices, thereby obstructing the straight-line propagation of light. This makes it possible to create a uniform light source, where even point light sources placed at intervals on a plane become a surface light source across the entire plane. Specifically, one method is to arrange irregularities with random or directional shapes in a random or regular pattern on the surface of a transparent plate. In the case of materials such as resin, this can be achieved by dispersing spherical particles called diffusers within the transparent plate, or by incorporating air like bubbles. The diffusers are not limited to spherical shapes; they may also have elliptical or nearly spherical shapes.

[0027] As shown in Figures 1 and 2, the diffuser plate 13 is positioned so that one surface faces the liquid L, and that the other surface is parallel to the surface of the liquid L that falls in a film-like manner. Also, as shown in Figures 1 and 2, multiple light-emitting elements 14 are arranged on the other surface of the diffuser plate 13, and ultraviolet light is emitted from that other surface. The ultraviolet light emitted by the multiple light-emitting elements 14 is diffused in a planar manner by the diffuser plate 13. In this way, a planar light source with a planar light-emitting surface is realized by the combination of the light-emitting elements 14 and the diffuser plate 13.

[0028] In Embodiment 1, as shown in Figures 1 and 2, there is a gap between the light-emitting element 14 and the diffuser plate 13, but the light-emitting element 14 and the diffuser plate 13 may be in contact. When there is a gap between the light-emitting element 14 and the diffuser plate 13, air exists between the light-emitting element 14 and the diffuser plate 13.

[0029] The receiving tray 15 is a container that receives the liquid that falls from the dripping part 10 vertically downwards. The receiving tray 15 has a discharge port (not shown), and the liquid received by the receiving tray 15 is discharged from the discharge port.

[0030] In Embodiment 1, two light sources 12 are provided to irradiate both sides of the film-like liquid L with ultraviolet light. However, it is also possible to use only one light source 12 and irradiate only one side of the film-like liquid L with ultraviolet light.

[0031] Next, the operation of the sterilization device 1 in Embodiment 1 will be described.

[0032] The liquid L that flows into the dripping section 10 from the inlet 16 falls as a thin film through the slit 17. The fallen liquid L is collected in the receiving tray 15 located vertically below the dripping section 10 and discharged from the outlet.

[0033] Here, the falling liquid L is irradiated with ultraviolet light emitted from the light source unit 12. Since the liquid L is in the form of a sufficiently thin flat film, the ultraviolet light passes through the liquid L. Therefore, even if the transmittance of the liquid L to ultraviolet light is low, it can be efficiently sterilized and inactivated.

[0034] Furthermore, the light source unit 12 diffuses the ultraviolet light emitted by the light-emitting element 14 using the diffuser plate 13, and the light-emitting surface has a planar shape. The main surface of the liquid L falling in a film is parallel to this light-emitting surface. Therefore, the liquid L can be sterilized uniformly and efficiently. In addition, since the light source unit 12 is positioned opposite the liquid L, ultraviolet light can be irradiated onto both sides of the liquid L, which has a flat film shape, allowing for more efficient sterilization and inactivation of the liquid L.

[0035] Furthermore, since the light source unit 12 uses a light-emitting element 14 to generate ultraviolet light, it is easy to control the on / off state and light intensity adjustment, and it can save power compared to conventional mercury lamps.

[0036] A sensor may be installed to detect the transmittance and flow rate of the liquid L, and the on / off status and light intensity of each light-emitting element 14 may be adjusted based on the detected information. This allows for the selection of an appropriate light intensity according to the turbidity and volume of the liquid L.

[0037] Furthermore, since the liquid L is simply dropped, there are no components to form a flow path for the liquid L. Therefore, the configuration of the sterilization device can be simplified and costs can be reduced. In addition, since there is no absorption of ultraviolet light by the flow path forming components, ultraviolet light can be directly irradiated onto the liquid L, thus improving sterilization efficiency.

[0038] Furthermore, the light intensity of the light-emitting surface of the light source unit 12 may be controlled to differ in the direction of gravity according to the falling speed of the liquid L. When liquid L is dropped, the greater the distance it falls, the faster its speed. Also, the sterilization efficiency depends on the light intensity and irradiation time, and the shorter the irradiation time, the lower the sterilization efficiency. Therefore, by making the light intensity of the light-emitting surface stronger towards the downward direction of gravity, sterilization can be performed more uniformly. In addition, the power consumption of the light-emitting device can be reduced. The distribution of light intensity can be formed by changing the number of light-emitting elements 14 or the light intensity of each individual light-emitting element 14. The light intensity of the light-emitting elements 14 can be controlled by the current value, etc.

[0039] Furthermore, when liquid L is dropped, variations in the shape of liquid L may occur in the direction of gravity. Therefore, by increasing the light intensity in the direction of gravity, sterilization and inactivation can be efficiently achieved even if there are variations in the shape of liquid L.

[0040] Furthermore, when liquid L is dropped, the shape of liquid L is less varied and more stable the higher it is in the direction of gravity. Therefore, by increasing the light intensity in the direction of gravity, more uniform sterilization and inactivation can be achieved.

[0041] (Embodiment 2) Figure 3 is a cross-sectional view in the direction of gravity showing the configuration of the sterilization device 2 in Embodiment 2. Figure 4 is a view of the sterilization device 2 in Embodiment 2 from above. As shown in Figures 3 and 4, the sterilization device 2 in Embodiment 2 has a dripping part 20, a light source part 22, and a receiving tray 25.

[0042] The dropping section 20 is a device for dropping liquid L, similar to the dropping section 10 in Embodiment 1. The dropping section 20 causes liquid L flowing in from the inlet 26 to fall through the slit 27. As shown in Figure 2, the slit 27 has the shape of a small circle. Therefore, the liquid L falls in a straight line. The diameter of the slit 27 is set to be a straight line that is narrow enough to allow sufficient ultraviolet light emitted by the light source 12 to pass through the liquid L. The fallen liquid L is caught by the receiving tray 25 and discharged from an outlet (not shown).

[0043] The light source unit 22 is a planar light source that irradiates ultraviolet light onto the liquid L dropped from the dropping section 20. The light source unit 22 has a diffuser plate 23 and a plurality of light-emitting elements 24. The light source unit 22 achieves light emission on the inner surface of the cylinder by diffusing the ultraviolet light emitted by the plurality of light-emitting elements 24 with the diffuser plate 23.

[0044] The light-emitting element 24 is the same as the light-emitting element 14 of Embodiment 1. That is, it is an element using a group III nitride semiconductor that emits ultraviolet light, and its emission wavelength is, for example, 200 to 300 nm. Multiple light-emitting elements 24 are arranged in a circumferential plane.

[0045] The diffuser plate 23 is cylindrical. The diffuser plate 23 is made of the same material as the diffuser plate 13 of Embodiment 1, and is made of a material that transmits ultraviolet light. For example, quartz or fluororesins such as PTFE and PFA can be used. The diffuser plate 23 is arranged so that the liquid L falling in a straight line becomes the central axis of the diffuser plate 23. In addition, a plurality of light-emitting elements 24 are arranged on the outer circumferential surface of the cylinder of the diffuser plate 23, and are arranged so that ultraviolet light is incident on the outer circumferential surface of the diffuser plate 23.

[0046] The ultraviolet light emitted by the multiple light-emitting elements 24 is diffused by the diffuser plate 23, and the ultraviolet light is emitted from the inner surface of the diffuser plate 23. This realizes a planar light source in which the light-emitting surface has the shape of the inner surface of a cylinder.

[0047] In Embodiment 2, the diffuser plate 23 is cylindrical, but it may also be rectangular. Alternatively, it may be rectangular with a cross-section of an equilateral triangle, square, or regular hexagon, arranged in a pattern that fills a plane, with a dripping portion 20 at the center of each.

[0048] The sterilization device 2 in Embodiment 2, like the sterilization device in Embodiment 1, can sterilize liquids uniformly and efficiently, and can sterilize even liquids with low transparency efficiently.

[0049] (Other variations) In Embodiment 1, the liquid L was dropped in a flat shape, and in Embodiment 2, it was dropped in a straight line, but the invention is not limited to these, and any shape that makes the liquid L thin is acceptable. For example, the liquid L may be in the form of a cylindrical or rectangular film. The shape of the light-emitting surface of the light source should be opposite to the surface of the film-like liquid L. The falling liquid L may widen towards the bottom, but the shape of the light-emitting surface may be controlled to match the widening shape. Specifically, it is preferable to make the surface that widens towards the bottom and the light-emitting surface parallel. The light-emitting surface of the light source can be any planar or curved shape depending on the shape of the diffuser plate. In this way, by selecting the optimal light-emitting surface shape according to the shape of the falling liquid L, even more uniform sterilization and inactivation can be achieved. Also, the liquid L does not need to be completely continuous in the direction of gravity, and may be intermittent.

[0050] The sterilization apparatus of Embodiments 1 and 2 is suitable when the permeability of the liquid L is low. For example, it is suitable for sterilizing milk, juice, tea, etc. [Explanation of Symbols]

[0051] 10, 20: Dripping part 12, 22: Light source section 13, 23: Diffuser 14, 24: Light-emitting elements 15, 25: Saucer 16:Inlet 17: Slit

Claims

1. A dropping part that drops the liquid in a film or line, The device includes a light source unit that irradiates the falling liquid with ultraviolet light and whose light-emitting surface has a planar shape, The sterilization device comprises a plurality of ultraviolet light-emitting elements and a diffuser plate that diffuses the ultraviolet light emitted by each of the light-emitting elements in a planar manner.

2. The sterilization apparatus according to claim 1, wherein the light intensity of the light-emitting surface of the light source differs in the direction of gravity according to the rate at which the liquid falls.

3. The sterilization apparatus according to claim 2, wherein the number of light-emitting elements is changed so that the light intensity of the light-emitting surface of the light source differs in the direction of gravity.

4. The sterilization apparatus according to claim 2, wherein the light intensity of each of the light-emitting elements is changed so that the light intensity of the light-emitting surface of the light source differs in the direction of gravity.

5. The sterilization apparatus according to claim 2, wherein the current value of the light-emitting element is controlled so that the light intensity of the light-emitting surface of the light source differs in the direction of gravity.

6. The sterilization apparatus according to claim 2, wherein the light intensity of the light-emitting surface of the light source unit increases as it moves downward in the direction of gravity.

7. The sterilization apparatus according to claim 2, wherein the light intensity of the light-emitting surface of the light source unit increases as it moves upward in the direction of gravity.

8. The dropping part causes the liquid to fall in a flat film-like manner. The sterilization apparatus according to claim 1 or claim 2, wherein the light source unit has a planar shape for the light-emitting surface and is arranged so that the surface of the liquid and the light-emitting surface are parallel.

9. The system has two of the aforementioned light source units, The sterilization apparatus according to claim 8, wherein the two light sources are arranged to face each other with the falling liquid in between.

10. The dropping part causes the liquid to fall in a linear fashion. The sterilization apparatus according to claim 1 or claim 2, wherein the light source unit has a shape in the form of the inner circumferential surface of a cylinder, and the liquid line is arranged to be the central axis of the cylinder.

11. The sterilization apparatus according to claim 1 or claim 2, wherein the diffusion plate is made of quartz or a fluorine-based resin.

12. Furthermore, it has a sensor for measuring the permeability or flow rate of the liquid, The sterilization apparatus according to claim 1 or claim 2, wherein each of the light-emitting elements is turned on or off, or the light intensity is adjusted, based on the transmittance or flow rate measured by the sensor.

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