Fluid sterilizer

Abstract

To provide a fluid sterilizer in which stains of a light source part are suppressed.SOLUTION: A fluid sterilizer has a flow channel part which forms a flow channel space for flowing fluid, and in which an inflow port and an outflow port are formed; and a light source part which is arranged in the flow channel space, and radiates ultraviolet light into the flow channel space, where the light source part has an ultraviolet light emitting element which emits ultraviolet light; a housing part which houses the ultraviolet light emitting element; and a window part which seals the housing part, and transmits ultraviolet light from the ultraviolet light emitting element, where an ultraviolet light photocatalyst film which is excited by ultraviolet light to exert a photocatalytic effect is provided on a surface of the housing part contacting fluid.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] There is known a sterilization device that sterilizes and inactivates bacteria and viruses in running water by irradiating ultraviolet light. A mercury lamp is widely used as a light source. Since the mercury lamp uses mercury, it has a problem of strong toxicity and a large environmental load. In addition, there is also a problem that the sterilization device becomes large when using a mercury lamp. Therefore, the replacement of the mercury lamp with an ultraviolet LED is in progress.

[0003] As fluid sterilization devices using ultraviolet LEDs, there are Patent Documents 1 and 2. Patent Documents 1 and 2 disclose a configuration in which a columnar light source portion that protrudes from one end of a flow path tube toward the other end side is provided.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in a configuration where the light source portion is in contact with the fluid to be sterilized as in Patent Documents 1 and 2, dirt adheres to the light source portion.

[0006] The present invention has been made in view of such a background, and aims to provide a fluid sterilization device in which dirt on the light source portion is suppressed.

Means for Solving the Problems

[0007] One aspect of the present invention is a fluid sterilization device having a flow path portion that forms a flow path space through which a fluid flows and has an inlet and an outlet, and a light source portion that is disposed in the flow path space and emits ultraviolet light into the flow path space, wherein the light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a housing portion that houses the ultraviolet light emitting element, and a window portion that seals the housing portion and transmits ultraviolet light from the ultraviolet light emitting element, and an ultraviolet photocatalyst film that is excited by ultraviolet light and exhibits a photocatalytic effect is provided on a surface of the housing portion that contacts the fluid.

[0008] Another aspect of the present invention is a fluid sterilization device having a flow path portion that forms a flow path space through which a fluid flows and has an inlet and an outlet, and a light source portion that is disposed in the flow path space and emits ultraviolet light and visible light into the flow path space, wherein the light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a visible light emitting element that emits visible light, a housing portion that houses the ultraviolet light emitting element and the visible light emitting element, and a window portion that seals the housing portion and transmits ultraviolet light from the ultraviolet light emitting element and visible light from the visible light emitting element, and a visible photocatalyst film that is excited by visible light and exhibits a photocatalytic effect is provided on a surface of the housing portion that contacts the fluid.

[0009] Another aspect of the present invention is a fluid sterilization device having a flow path tube that forms a flow path space through which a fluid flows and has an inlet and an outlet, a light source portion that is disposed in the flow path space and emits ultraviolet light into the flow path space, and a second light source portion that emits visible light into the flow path space, wherein the light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a housing portion that houses the ultraviolet light emitting element, It has a window portion that seals the storage portion and transmits ultraviolet light from the ultraviolet light emitting element. The second light source unit includes a visible light emitting element that emits visible light, a second storage portion that houses the visible light emitting element, and has a second window portion that seals the second storage portion and transmits visible light from the visible light emitting element. A visible light photocatalyst film that is excited by visible light and exhibits a photocatalytic effect is provided on the surface of the storage portion that contacts the fluid. In the fluid sterilization device, an ultraviolet light photocatalyst film that is excited by ultraviolet light and exhibits a photocatalytic effect is provided on the surface of the second storage portion that contacts the fluid.

Advantages of the Invention

[0010] In the above aspect, a photocatalyst film is provided on the surface of the storage portion that contacts the fluid, and it is excited by ultraviolet light or visible light to exhibit a photocatalytic effect. Therefore, the adhesion of dirt to the storage portion can be suppressed.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0012] The first fluid sterilization device includes a flow path portion that forms a flow path space through which a fluid flows and has an inlet and an outlet, and a light source portion that is disposed in the flow path space and emits ultraviolet light into the flow path space. The light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a storage portion that houses the ultraviolet light emitting element, and a window portion that seals the storage portion and transmits the ultraviolet light from the ultraviolet light emitting element. An ultraviolet photocatalyst film that is excited by ultraviolet light and exhibits a photocatalytic effect is provided on the surface of the storage portion that contacts the fluid.

[0013] The second fluid sterilization device includes a flow path portion that forms a flow path space through which a fluid flows and has an inlet and an outlet, and a light source portion that is disposed in the flow path space and emits ultraviolet light and visible light into the flow path space. The light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a visible light emitting element that emits visible light, a storage portion that houses the ultraviolet light emitting element and the visible light emitting element, and a window portion that seals the storage portion and transmits the ultraviolet light from the ultraviolet light emitting element and the visible light from the visible light emitting element. A visible light photocatalyst film that is excited by visible light and exhibits a photocatalytic effect is provided on the surface of the storage portion that contacts the fluid.

[0014] The third fluid sterilization device includes a flow path tube that forms a flow path space through which a fluid flows and has an inlet and an outlet, a light source portion that is disposed in the flow path space and emits ultraviolet light into the flow path space, and a second light source portion that emits visible light into the flow path space. The light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a storage portion that houses the ultraviolet light emitting element, and a window portion that seals the storage portion and transmits the ultraviolet light from the ultraviolet light emitting element. The second light source portion includes a visible light emitting element that emits visible light, a second storage portion that houses the visible light emitting element, and a second window portion that seals the second storage portion and transmits the visible light from the visible light emitting element. A visible light photocatalyst film that is excited by visible light and exhibits a photocatalytic effect is provided on the surface of the storage portion that contacts the fluid, and an ultraviolet photocatalyst film that is excited by ultraviolet light and exhibits a photocatalytic effect is provided on the surface of the second storage portion that contacts the fluid.

[0015] In the first fluid sterilization device or the third fluid sterilization device, the flow path space may have an ultraviolet light reflecting film that reflects ultraviolet light and irradiates the ultraviolet photocatalyst film.

[0016] In the second fluid sterilization device or the third fluid sterilization device, the flow path space may have a visible light reflecting film that reflects visible light and irradiates the visible light photocatalyst film.

[0017] In the second fluid sterilization device or the third fluid sterilization device, the flow path space may have a reflecting film that reflects ultraviolet light and visible light and irradiates the visible light photocatalyst film.

[0018] A second ultraviolet photocatalyst film that is excited by ultraviolet light and exhibits a photocatalytic effect may be provided on the surface of the ultraviolet light reflecting film.

[0019] A photocatalyst film that is excited by ultraviolet light or visible light and exhibits a photocatalytic effect may be provided on the surface of the visible light reflecting film.

[0020] A photocatalyst film that is excited by ultraviolet light or visible light and exhibits a photocatalytic effect may be provided on the surface of the reflecting film.

[0021] (Embodiment 1) 1. Outline of the Configuration of the Fluid Sterilization Device 1 FIG. 1 is a perspective view showing the configuration of the fluid sterilization device 1 in Embodiment 1. As shown in FIG. 1, the fluid sterilization device in Embodiment 1 has a flow path tube 100 and two light source units 110 inside it. In FIG. 1, an X-axis is taken in the direction of the central axis O of the flow path tube 100, a Y-axis is taken in a direction perpendicular to the X-axis and parallel to the central axis L1 of the inlet, and a Z-axis is taken in a direction perpendicular to the X-axis and the Y-axis.

[0022] FIG. 2 is a cross-sectional view showing the configuration of the fluid sterilization apparatus according to Embodiment 1, which is a cross-section (ZX plane) taken along line II-II in FIG. 1. As shown in FIG. 2, inside the flow path tube 100, light source units 110 are respectively arranged at both ends of the flow path tube 100. Further, FIG. 3 is a cross-sectional view showing the configuration of the fluid sterilization apparatus according to Embodiment 1, which is a view showing a part (the first end portion 100a side) of the cross-section (XY plane) taken along line III-III in FIG. 1. Further, FIG. 4 is a cross-sectional view showing the configuration of the fluid sterilization apparatus according to Embodiment 1, where FIG. 4(a) is a cross-section (YZ plane) taken along line IVa-IVa in FIG. 1, and FIG. 4(b) is a cross-section (YZ plane) taken along line IVb-IVb in FIG. 1.

[0023] The fluid sterilization apparatus 1 according to Embodiment 1 is an apparatus that flows a fluid from the inlet 101 of the flow path tube 100 into the flow path space inside the flow path tube 100, irradiates the fluid with ultraviolet light from the light source unit 110 to sterilize the fluid, and discharges the sterilized fluid from the outlet 102. The fluid to be sterilized may be a gas or a liquid, and may be a mixture of a gas and a liquid, a mixture of a gas and a powdery solid, etc., as long as it has fluidity. In the case of a liquid, for example, it is water, oil, alcohol, a solution using these as solvents, etc.

[0024] 2. Details of each component of the fluid sterilization apparatus 1 Next, each component of the fluid sterilization apparatus 1 according to Embodiment 1 will be described in detail.

[0025] 2-1. Configuration of the flow path tube 100 The flow path tube 100 is cylindrical and has a cylindrical space inside. This space is the flow path space through which the fluid to be sterilized flows. Light source units 110 are provided at both ends. Here, one end of the flow path tube 100 is the first end portion 100a, the other end is the second end portion 100b, the one provided on the first end portion 100a side among the two light source units 110 is the light source unit 110a, and the one provided on the second end portion 100b side is the light source unit 110b. Further, an inlet 101 is provided on the side wall of the first end portion 100a side of the flow path tube 100, and an outlet 102 is provided on the side wall of the second end portion 100b side. The inlet 101 and the outlet 102 are cylindrical and have a flow path region through which the fluid flows.

[0026] The material of the flow path tube 100 is SUS (stainless steel), titanium, PTFE (polytetrafluoroethylene), etc. It may also be a resin material resistant to ultraviolet light with its inner wall surface covered with a material having a high reflectivity of ultraviolet light. The resin material resistant to ultraviolet light is, for example, vinyl chloride. Also, the material having a high reflectivity of ultraviolet light is aluminum, PTFE, etc. Further, it may be a structure in which the outer wall surface of a material that transmits ultraviolet light is covered with a material having a high reflectivity of ultraviolet light. The material that transmits ultraviolet light is, for example, sapphire, ultraviolet-transmitting glass, fluororesin, acrylic resin, etc.

[0027] The inner wall surface of the flow path tube 100 preferably has an arithmetic mean roughness Ra of 0.2 nm to 10 μm. This reduces the resistance of the inner wall surface and makes it easier to maintain the flow. More preferably, it is 0.2 nm to 3 μm, and even more preferably, it is 0.2 nm to 1 μm.

[0028] As shown in Fig. 4(a), the inlet 101 is arranged such that the inflow direction of the fluid flowing in from the inlet 101 is offset with respect to the central axis O of the flow path tube 100. That is, the flow path central axis (hereinafter simply referred to as the central axis of the inlet 101) L1, which is the central axis of the flow path region of the inlet 101, coincides with a direction parallel to the line intersecting the central axis O of the flow path tube 100 and not intersecting the central axis O of the flow path tube 100. When viewed in cross-section as in Fig. 4(a), the central axis L1 of the inlet 101 is displaced by Y1 in the Y direction so as not to pass through the central axis O of the flow path tube 100. By offsetting the position of the inlet 101 in this way, a spiral flow can be formed in the flow path space within the flow path tube 100, and the tangential direction of the spiral flow is the direction of the central axis L1 of the inlet 101. Also, as shown in Fig. 2, the angle formed by the central axis L1 of the inlet 101 and the central axis O is 90 degrees. It does not necessarily have to be 90 degrees, but 80 to 100 degrees is preferred.

[0029] The outlet 102 is also arranged such that the outflow direction is offset with respect to the central axis O of the flow path tube 100, as shown in Fig. 4(b). That is, the central axis of the flow path region of the outlet 102 (hereinafter simply referred to as the central axis of the outlet 102) L2 is in a direction parallel to the line intersecting the central axis O of the flow path tube 100 and does not coincide with the direction intersecting the central axis O of the flow path tube 100. When viewed in cross-section as in Fig. 4(b), the central axis L2 of the outlet 102 is displaced by Y2 in the Y direction so as not to pass through the central axis O of the flow path tube 100. As a result, a spiral flow can be maintained also on the outlet 102 side, and the tangential direction of the spiral flow is the direction of the central axis L2 of the outlet 102. Y1 and Y2 may be different, but it is preferably as close as possible, and particularly preferably the same value.

[0030] 2-2. Configuration of the light source unit 110 The light source unit 110 has an LED package 140, a column part 120, and a storage part 130. Hereinafter, the light source unit 110a provided on the first end part 100a side will be described, but the light source unit 110b provided on the second end part 100b side has the same configuration.

[0031] As shown in Fig. 2, the column part 120 protrudes from the first end to the second end side of the flow path tube 100 and has a frustum-shaped part. The central axis of the column part 120 coincides with the central axis of the flow path tube 100. The inclination angle (angle with respect to the bottom surface) of the side surface of the frustum is, for example, 30 to 70°. One end with a thicker diameter of the column part 120 is connected to the first end of the flow path tube 100, and one end with a thinner diameter is connected to the storage part 130.

[0032] Note that the shape of the column part 120 is not limited to a frustum shape, and any shape may be used as long as it becomes thinner toward the second end side. A stepwise-thinning shape may be used, but a continuously-thinning shape is preferred. For example, a truncated pyramid shape may be used. However, a frustum shape is preferred for forming a spiral flow. Also, the entire column part 120 does not have to be a frustum, and a part may be a frustum and the other part may be a cylinder. For example, as shown in Fig. 1, the tip side connected to the storage part 130 may be cylindrical and the other part may be frustum-shaped.

[0033] The storage part 130 is connected to the tip of the column part 120. The storage part 130 stores the LED package 140. The storage part 130 has a glass plate 132, a pedestal part 133, and a substrate 135.

[0034] The pedestal part 133 is a cylindrical box shape with an open top surface, and the outer bottom surface is connected to the tip of the column part 120. The substrate 135 is arranged on the bottom surface inside the box, and the LED package 140 is mounted on the substrate 135. The glass plate 132 is provided on the top surface of the box, sealing the inside of the box. The glass plate 132 is a material that transmits ultraviolet light from the LED package 140, such as quartz or sapphire. A photocatalytic film that transmits ultraviolet light may be provided on the surface of the glass plate 132 to suppress the growth of miscellaneous bacteria on the glass plate 132 or prevent organic matter stains. The glass plate 132 is not limited to a flat plate and may be lens-shaped. For example, it may be a TIR lens, a fly-eye lens, a Fresnel lens, etc.

[0035] As shown in FIG. 2, the pedestal part 133 is formed so as to extend radially outward from the tip of the column part 120 over the entire circumference of the tip of the column part 120. Therefore, the back surface of the pedestal part 133 will be in contact with the flow path space except for the region connected to the column part 120.

[0036] The pedestal part 133 has a peripheral wall 136 that protrudes toward the first end side in the outer peripheral region of its back surface, and has a recess 134 surrounded by the back surface of the pedestal part 133 and the peripheral wall 136. In Embodiment 1, it is not necessary to provide the peripheral wall 136 over the entire circumference, and it is preferably provided partially. If it is provided over the entire circumference, an air pocket will form in the recess 134 and the cooling efficiency will deteriorate. Also, the peripheral wall 136 is preferably provided outside the LED package 140 when viewed in the central axis direction of the flow path pipe 100. That is, it is preferable that the LED package 140 is located within the region of the recess 134. The pedestal part 133 can be cooled more efficiently.

[0037] In Embodiment 1, the pedestal portion 133 is formed in a cylindrical box shape, but any shape may be used as long as it is box-shaped. For example, it may be a box shape with a square prism shape (a square box). However, from the viewpoint of generating a spiral flow, it is preferable to use a cylindrical box shape as in Embodiment 1.

[0038] The materials of the column portion 120 and the pedestal portion 133 are titanium. As shown in FIG. 3, a photocatalytic film 150 is provided in a region that contacts the fluid on the surfaces of the column portion 120 and the pedestal portion 133. Specifically, the regions that contact the fluid are, for example, the upper surface, side surfaces, back surface of the pedestal portion 133, and the side surface of the column portion 120.

[0039] The photocatalytic film 150 is made of titanium oxide. This is formed by subjecting the surfaces of the column portion 120 and the pedestal portion 133 made of titanium to an oxidation treatment. Since the ultraviolet light from the light source portion 110b on the second end side irradiates the photocatalytic film 150 of the light source portion 110a on the first end side, the photocatalytic film 150 exhibits a photocatalytic effect. As a result, it is possible to suppress the propagation of germs and the adhesion of dirt in the regions of the column portion 120 and the pedestal portion 133 that contact the fluid.

[0040] The materials of the column portion 120 and the pedestal portion 133 are not limited to titanium, and the photocatalytic film 150 is not limited to a surface oxide film. For example, a metal material with high thermal conductivity such as SUS or aluminum, or a high heat dissipation resin mixed with a thermal conductive filler can be used. Further, the photocatalytic film 150 may be formed by sputtering or the sol-gel method. Further, titanium oxide may be mixed with a fluororesin or the like and applied. Further, the material of the photocatalytic film 150 is not limited to titanium oxide, and iron oxide, zinc oxide, tungsten oxide, etc. can be used.

[0041] Further, some of the plurality of mounted LED packages 140 may be replaced with those for exciting the photocatalytic film 150. For example, as the material of the photocatalytic film 150, a material (for example, copper) that is excited by visible light and exhibits a photocatalytic effect may be used, and one of the plurality of LED packages 140 may be a package equipped with a light emitting element that emits visible light.

[0042] For the light-emitting element that emits visible light, for example, an LED package 140 with an emission wavelength of 385 nm or more may be used. Since the LED package 140 with an emission wavelength of 385 nm or more has a higher luminous efficiency than ultraviolet light emission, the photocatalytic effect of the photocatalytic film 150 made of Cu can be more efficiently exerted. Of course, in this case, the glass plate 132 is made of a material that transmits both ultraviolet light and visible light. Also, since the material of the reflection film 160 described later only needs to be a material that reflects visible light, the range of material selection is widened.

[0043] Also, on the end face of the first end side of the flow path tube 100, a reflection film 160 that reflects ultraviolet light from the light source part 110b on the second end side is provided. By providing the reflection film 160, the irradiation amount of ultraviolet light to the photocatalytic film 150 can be increased, and the photocatalytic effect of the photocatalytic film 150 can be more effectively exerted. Also, the irradiation amount of ultraviolet light to the fluid can be increased, and further improvement in sterilization efficiency can be achieved. The material of the reflection film 160 only needs to be a material that can reflect ultraviolet light, for example, aluminum, magnesium, SUS, PTFE, titanium, resins such as fluorine-coated vinyl chloride, etc.

[0044] In addition, when the photocatalytic film 150 is a material that can be excited by visible light, a material that reflects visible light may be used for the reflection film 160. In particular, a material that reflects both visible light and ultraviolet light is preferable. In addition to increasing the irradiation amount of visible light to the photocatalytic film 150, the irradiation amount of ultraviolet light to the fluid can be increased. For example, aluminum is suitable because it has a high reflectivity for both visible light and ultraviolet light.

[0045] A photocatalyst film may be provided on the surface of the reflective film 160. Since the reflective film 160 also comes into contact with the fluid, dirt may adhere to it, but this can be suppressed by providing the photocatalyst film. The material and formation method of the photocatalyst film formed on the reflective film 160 are the same as those of the reflective film 160. When a material excited by ultraviolet light is used as the photocatalyst film 150, the photocatalyst film on the reflective film 160 uses a material excited by ultraviolet light. When a material excited by visible light is used as the photocatalyst film 150, the photocatalyst film on the reflective film 160 may be a material excited by ultraviolet light or a material excited by visible light.

[0046] In addition, in Embodiment 1, the light source units 110a and 110b have the same configuration. However, the photocatalyst film 150 of the light source unit 110a is a material excited by ultraviolet light, and the photocatalyst film 150 of the light source unit 110b is a material excited by visible light. The light source unit 110a may be configured to mount the LED package 140 that emits visible light, and the light source unit 110b may not mount the LED package 140 that emits visible light. Alternatively, the reverse configuration may be used.

[0047] The LED package 140 is mounted on the substrate 135. A plurality of LED packages 140 may be mounted, and in FIG. 2, two are mounted. The LED package 140 has an LED, a substrate on which the LED is mounted, and a lens that seals the LED.

[0048] The LED is a light-emitting element that emits ultraviolet light. The wavelength of the ultraviolet light is preferably 250 to 285 nm, which is a wavelength with high sterilization efficiency. A plurality of LEDs may be provided in one LED package 140.

[0049] The LED package 140 is preferably mounted in a region outside the column portion 120 when viewed from the central axis direction of the flow path tube 100. Since the fluid can be brought into contact with the region directly below the LED package 140 on the back surface of the pedestal portion 133, the storage portion 130 can be efficiently cooled.

[0050] In Embodiment 1, the packaged LED package 140 is mounted on the substrate 135, but the LED may be directly mounted on the substrate 135.

[0051] A continuous through-hole 111 is provided in the center of the column portion 120 and the storage portion 130. This hole 111 is a hole through which a wiring cable that supplies power to the LED package 140 and circuit components on the mounting substrate passes. The wiring cable is drawn into the mounting substrate through this hole 111.

[0052] 3. Regarding the fluid flow path The fluid flow path flowing in the flow path tube 100 will be described with reference to FIG. 5. FIG. 5(a) is a diagram schematically showing the flow path on the first end portion 100a side (the inlet 101 side) of the flow path tube 100, and FIG. 5(b) is a diagram schematically showing the flow path on the second end portion 100b side (the outlet 102 side) of the flow path tube 100.

[0053] As shown in FIG. 5(a), the fluid that has entered the flow path space in the flow path tube 100 from the inlet 101 flows around the column portion 120 of the light source portion 110a. This is because the inlet 101 is offset from the central axis O of the flow path tube 100, and the position, shape, and size of the inlet 101 are set to go around the periphery of the column portion 120. When looking in the direction of the central axis O of the flow path tube 100, in the direction from the first end portion 100a to the second end portion 100b, the fluid flows in a counterclockwise rotation.

[0054] The fluid flowing around the column portion 120 hits the side surface of the frustum-shaped portion of the column portion 120. Therefore, the fluid is reflected in the axial direction due to the inclination of the side surface, and a flow path toward the storage portion 130 is formed. Therefore, the fluid can be efficiently brought into contact with the storage portion 130, and the cooling efficiency can be improved.

[0055] In addition, since the pedestal portion 133 is formed so as to extend radially outward from the tip of the column portion 120 over the entire circumference of the tip of the column portion 120, the back surface of the pedestal portion 133 can be brought into contact with the fluid. In particular, the fluid comes into contact with the region of the back surface of the pedestal portion 133 that lies directly below the LED package 140. Therefore, the pedestal portion 133 can be efficiently cooled.

[0056] Also, since a peripheral wall 136 is provided on the back surface of the pedestal portion 133 and there is a recess 134 surrounded by the peripheral wall 136, the fluid tends to stay on the back surface of the pedestal portion 133. Therefore, heat can be efficiently conducted from the back surface of the pedestal portion 133 to the fluid, and the cooling efficiency can be improved.

[0057] Thereafter, the fluid flows in the central axis direction while rotating around the central axis O in the ring-shaped region between the storage portion 130 and the inner wall surface of the flow path pipe 100. As a result, a spiral flow F1 is formed. By making it the spiral flow F1, the residence time of the fluid in the flow path space becomes longer and the irradiation time of ultraviolet light to the fluid becomes longer, so that the sterilization efficiency can be improved.

[0058] On the other hand, on the second end portion 100b side, as shown in FIG. 5(b), the spiral flow F2 is maintained. This is because a clean spiral flow F1 is formed on the first end portion 100a side, and there is little breakdown of the spiral flow F1 even at a distance. Therefore, also on the second end portion 100b side, the irradiation time of ultraviolet light becomes longer, and the sterilization efficiency can be improved.

[0059] Also, on the second end portion 100b side as well, in the ring-shaped region between the housing portion 130 of the light source portion 110b and the inner wall surface of the flow path tube 100, fluid passes in the direction of the central axis O while rotating around the central axis O. Then, the fluid flows out from the outlet 102 while circulating around the column portion 120 of the light source portion 110b. The outlet 102 is also offset from the central axis O of the flow path tube 100, similar to the inlet 101, and the position, shape, and size of the outlet 102 are set to circulate around the column portion 120. Therefore, the fluid can flow out smoothly from the outlet 102, and the pressure loss can be reduced.

[0060] Also, a part of the fluid circulating around the column portion 120 of the light source portion 110b is reflected by the side surface of the column portion 120, and a flow path F0 is formed that heads toward the housing portion 130 of the light source portion 110b. Therefore, the housing portion 130 of the light source portion 110b can be efficiently cooled.

[0061] 5. Summary As described above, in the fluid sterilization device according to Embodiment 1, a photocatalytic film 150 that is excited by the light from the light source portion 110 and exhibits a photocatalytic effect is provided in the region of the surface of the column portion 120 and the surface of the pedestal portion 133 that comes into contact with the fluid. Therefore, it is possible to suppress the adhesion of dirt to the column portion 120 and the pedestal portion 133.

[0062] (Modification 1 of Embodiment 1) FIG. 6 is a diagram schematically showing the configuration of the light source portion 210 of the fluid sterilization device according to Modification 1 of Embodiment 1. As shown in FIG. 6(a), the light source portion 210 has a column portion 220 and a housing portion 230. The column portion 220 has the same configuration as the column portion 120 in Embodiment 1. The housing portion 230 has a configuration in which the pedestal portion 133 of the housing portion 130 in Embodiment 1 is replaced with a pedestal portion 233, and the other configurations are the same as those of the housing portion 130. The pedestal portion 233 has a configuration in which the peripheral wall 136 is removed from the pedestal portion 133, and the outer peripheral region of the back surface of the pedestal portion 233 is flat.

[0063] A photocatalytic film 231 is provided on the surfaces of the pedestal portion 233 and the column portion 220 that come into contact with the fluid. The photocatalytic film 231 is made of the same material as the photocatalytic film 150 in Embodiment 1. This photocatalytic film 231 can suppress the adhesion of dirt to the pedestal portion 233 and the column portion 220.

[0064] Also, in Modification 1 of Embodiment 1, although the effect of retaining the fluid on the back surface of the storage portion 230 by the peripheral wall 136 cannot be obtained, other effects can be obtained in the same manner as in Embodiment 1.

[0065] In Modification 1 of Embodiment 1, in the light source portion 210 on the inlet 101 side, a groove 237 may be provided on the back surface of the storage portion 230 (the back surface of the pedestal portion 233) so as to guide the fluid from the center side to the outer peripheral side of the back surface of the storage portion. Alternatively, a wall-like protrusion may be provided instead of the groove 237.

[0066] Figures 6(b) and (c) are cross-sectional views showing the cross-section at VI-VI in Figure 6(a). Figure 6(b) shows the case where a spiral groove 237 is provided on the back surface of the pedestal portion 233. The center of the spiral is the center of the column portion 220. By providing such a spiral groove 237, the contact time between the fluid and the storage portion 230 becomes longer, so that efficient cooling can be achieved. In addition, a spiral flow path can be formed toward the outer periphery of the back surface of the storage portion 230, and the fluid passing between the inner wall of the flow path tube 100 and the storage portion 230 is likely to form a spiral flow.

[0067] Figure 6(c) shows the case where a radial groove 237 is provided on the back surface of the pedestal portion 233. By providing such a groove 237, the fluid can be guided to the outer periphery.

[0068] Also, in the light source portion 210 on the outlet 102 side, a groove 237 may be provided as shown in Figures 6(b) and (c). The storage portion 230 can be efficiently cooled. In addition, the fluid that has passed between the inner wall of the flow path tube 100 and the storage portion 230 can be guided to the column portion 220 side, and then a smooth flow path can be formed toward the outlet 102 side by reflection by the column portion 220.

[0069] (Modification 2 of Embodiment 1) The column portion 120 may be cylindrical. Although there is no effect of directing the fluid toward the storage portion 430, other effects can be obtained in the same manner as in Embodiment 1. Also, the storage portion 130 may be the same as in Embodiment 1.

[0070] (Modification 3 of Embodiment 1) The back surface of the pedestal portion 133 may be made to coincide with the tip of the column portion 120, and there may be no portion protruding radially outward from the column portion 120. Although the fluid cannot be brought into contact with the back surface of the storage portion 130 for cooling, other effects can be obtained in the same manner as in Embodiment 1.

[0071] (Modification 4 of Embodiment 1) A light intensity sensor may be provided at the central portion of the flow path tube 100. The light intensity sensor is a sensor that detects the intensity of ultraviolet light at the central portion within the flow path tube 100. For example, the outputs of the two light source portions 110 are controlled so that the intensity of ultraviolet light at the central portion becomes a predetermined value or more.

[0072] Also, the light intensity sensor may also serve as a rectifying plate. The light intensity sensor is provided on the inner wall of the flow path tube 100 and is a wall-like protrusion protruding toward the central axis side of the flow path tube 100. The light intensity sensor is wall-like along the direction of the spiral flow, and thereby the spiral flow can be maintained at the central portion of the flow path tube 100.

[0073] (Modification 5 of Embodiment 1) Spiral grooves may be provided on the inner wall of the flow path tube 100. By providing spiral grooves 700 in the flow path tube 100, it becomes easy to maintain a spiral flow in the flow path space, and the sterilization efficiency can be improved.

[0074] (Other Modifications) In the fluid sterilization device according to the embodiment, light source units 110a and 110b are provided on each of the inlet 101 side and the outlet 102 side. However, when the flow path tube 100 is short, etc., the light source unit 110a may be provided only on the inlet 101 side. In this case, it is preferable to dispose a reflection film 160 that reflects the light from the light source unit 110a on the end face on the second end side. The reflection film 160 can reflect the light from the light source unit 110a, and the sterilization efficiency can be improved by irradiating the fluid with the reflected light. Further, the reflected light can be irradiated onto the photocatalyst film 150 of the light source unit 110a, and the photocatalytic effect can be further enhanced.

[0075] Alternatively, the light source unit 110 may be provided only on the outlet 102 side. Also in this case, the sterilization efficiency can be improved by providing the reflection film 160 on the end face on the first end side. Further, the photocatalytic effect of the photocatalyst film 150 of the light source unit 110b can be further enhanced.

[0076] In Embodiment 1, the flow path tube 100 is straight, but other shapes may be used, such as other tubular shapes like a U-shaped tube, or a spherical shape, etc. Also, the positions of the inlet 101 and the outlet 102 may be arbitrary. Further, the light source unit 110 may be at an arbitrary position as long as it is within the flow path space.

Explanation of Reference Numerals

[0077] 100: Flow path tube 101: Inlet 102: Outlet 110, 110a, 110b, 210: Light source unit 111: Hole 120: Column portion 130: Storage portion 132: Glass plate 133: Base portion 134: Concave portion 135: Substrate 136: Peripheral wall 140: LED package 150, 231: Photocatalyst film 160: Reflection film

Claims

1. A fluid sterilization device having a flow path portion that forms a flow path space for flowing a fluid and has an inlet and an outlet, and a light source portion disposed in the flow path space and emitting ultraviolet light into the flow path space, wherein the light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a housing portion that houses the ultraviolet light emitting element, and a window portion that seals the housing portion and transmits ultraviolet light from the ultraviolet light emitting element, and an ultraviolet photocatalyst film that is excited by ultraviolet light and exhibits a photocatalytic effect is provided on a surface of the housing portion that contacts the fluid. The fluid sterilization device.

2. A fluid sterilization device having a flow path portion that forms a flow path space for flowing a fluid and has an inlet and an outlet, and a light source portion disposed in the flow path space and emitting ultraviolet light and visible light into the flow path space, wherein the light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a visible light emitting element that emits visible light, a housing portion that houses the ultraviolet light emitting element and the visible light emitting element, and a window portion that seals the housing portion and transmits ultraviolet light from the ultraviolet light emitting element and visible light from the visible light emitting element, and a visible light photocatalyst film that is excited by visible light and exhibits a photocatalytic effect is provided on a surface of the housing portion that contacts the fluid. The fluid sterilization device.

3. A fluid sterilization device having a flow path tube that forms a flow path space for flowing a fluid and has an inlet and an outlet, a light source portion disposed in the flow path space and emitting ultraviolet light into the flow path space, and a second light source portion that emits visible light into the flow path space, wherein the light source portion includes an ultraviolet light emitting element that emits ultraviolet light, a housing portion that houses the ultraviolet light emitting element, and a window portion that seals the housing portion and transmits ultraviolet light from the ultraviolet light emitting element, wherein the second light source portion includes a visible light emitting element that emits visible light, a second housing portion that houses the visible light emitting element, and a second window portion that seals the second housing portion and transmits visible light from the visible light emitting element, and a visible light photocatalyst film that is excited by visible light and exhibits a photocatalytic effect is provided on a surface of the housing portion that contacts the fluid, and an ultraviolet photocatalyst film that is excited by ultraviolet light and exhibits a photocatalytic effect is provided on a surface of the second housing portion that contacts the fluid. The fluid sterilization device.

4. The fluid sterilization device according to claim 1 or claim 3, further comprising an ultraviolet light reflecting film in the flow path space for reflecting ultraviolet light and irradiating the ultraviolet photocatalyst film.

5. The fluid sterilization device according to claim 2 or claim 3, having a visible light reflecting film that reflects visible light and irradiates the visible light photocatalyst film.

6. The fluid sterilization device according to claim 2 or claim 3, having a reflecting film that reflects ultraviolet light and visible light and irradiates the visible light photocatalyst film.

7. The fluid sterilization device according to claim 4, wherein a second ultraviolet light photocatalyst film that is excited by ultraviolet light and exhibits a photocatalytic effect is provided on the surface of the ultraviolet light reflecting film.

8. The fluid sterilization device according to claim 5, wherein a photocatalyst film that is excited by ultraviolet light or visible light and exhibits a photocatalytic effect is provided on the surface of the visible light reflecting film.

9. The fluid sterilization device according to claim 6, wherein a photocatalyst film that is excited by ultraviolet light or visible light and exhibits a photocatalytic effect is provided on the surface of the reflecting film.

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