Fluid sterilizer

Abstract

To provide a low-cost fluid sterilizer having a flow path tube with high reflectance.SOLUTION: A fluid sterilizer comprises a cylindrical flow path tube 100 through which a fluid flows, and a light source unit 110 for irradiating inside the flow path tube 100 with ultraviolet light. The flow path tube 100 comprises a transparent tube 105 that transmits ultraviolet light, and an aluminum film 106 wound on the outer peripheral surface of the transparent tube 105. The aluminum film 106 is arranged in a manner so as not in close contact with at least part of the outer peripheral surface of the transparent tube 105, and so as to have a first air layer (air layer 104).SELECTED DRAWING: Figure 1

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] Patent Document 1 shows a sterilization device having a flow path tube through which a fluid flows and a light source that irradiates ultraviolet light toward the fluid in the flow path tube from one end side of the flow path tube. Further, Patent Document 1 shows a configuration in which a reflective film is provided on the outer peripheral surface of a transparent quartz tube as the flow path tube, and it is described that the reflective film is an aluminum vapor deposition film.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, since the reflective film is formed by vapor deposition, it is time-consuming and costly.

[0006] The present invention has been made in view of such a background, and an object thereof is to provide a fluid sterilization device including a flow path tube with low cost and high reflectivity.

Means for Solving the Problems

[0007] One aspect of the present invention is A fluid sterilization device having a cylindrical flow path tube through which a fluid flows and a light source unit that irradiates ultraviolet light inside the flow path tube. The flow path tube A transparent tube that transmits the ultraviolet light, And an aluminum film wound around the outer peripheral surface of the transparent tube. In the fluid sterilization device, the aluminum film is arranged so as not to be in close contact with at least a part of the outer peripheral surface of the transparent tube and to have a first air layer.

Effect of the Invention

[0008] In the above aspect, the aluminum film is arranged so as not to be in close contact with at least a part of the outer peripheral surface of the transparent tube and to have a first air layer. Therefore, reflection can be caused at the interface between the transparent tube and the first air layer and at the interface between the first air layer and the aluminum film. Therefore, a fluid sterilization device having a flow path tube with a high reflectance at low cost can be realized.

Brief Description of the Drawings

[0009]

Figure 1

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Figure 10

Mode for Carrying Out the Invention

[0010] The fluid sterilization device includes a cylindrical flow path tube through which fluid flows inside, and a light source unit that irradiates ultraviolet light inside the flow path tube. The flow path tube includes a transparent tube that transmits ultraviolet light, and an aluminum film wound around the outer peripheral surface of the transparent tube. The aluminum film is arranged so as not to be in close contact with at least a part of the region of the outer peripheral surface of the transparent tube and has a first air layer.

[0011] In the fluid sterilization device, the aluminum films may be wound so that the aluminum films overlap each other, and an adhesive layer may be provided between the aluminum films.

[0012] In the fluid sterilization device, the aluminum film may be arranged so as to have a first air layer between the entire outer peripheral surface of the transparent tube. The reflectivity of the flow path tube can be further increased.

[0013] In the fluid sterilization device, a part of the inner surface region of the aluminum film has an adhesive layer, the transparent tube and the aluminum film are adhered by the adhesive layer, and a first air layer may exist around the adhesive layer. In this case, the adhesive layer may be a periodic pattern. While adhering the transparent tube and the aluminum film, the adhesive layer can function as a spacer to form a first air layer.

[0014] In the fluid sterilization device, the flow path tube may further include a light-shielding tube that covers the outer periphery of the aluminum film and shields ultraviolet light from the light source unit. Leakage of ultraviolet light from the flow path tube to the outside can be suppressed.

[0015] In the fluid sterilization device, a second air layer may be provided between the aluminum film and the light-shielding tube. The reflectance can be further increased.

[0016] In the fluid sterilization device, the aluminum film is wound in a C-shaped cylindrical form, and the light-shielding tube has a convex portion protruding inward on its inner peripheral surface, and the convex portion may be fitted into the gap of the aluminum film in a C-shape. The displacement of the aluminum film can be suppressed.

[0017] (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 the direction perpendicular to the X-axis and perpendicular to the central axis L1 of the inlet, and a Z-axis is taken in the direction perpendicular to the X-axis and the Y-axis.

[0018] FIG. 2 is a cross-sectional view showing the configuration of the fluid sterilization device in Embodiment 1, which is a cross-section (ZX plane) at II-II in FIG. 1. As shown in FIG. 2, inside the flow path tube 100, the light source units 110 are respectively arranged at both ends of the flow path tube 100. Further, FIG. 3 is a diagram schematically showing a cross-section of the central portion of the flow path tube 100, which is a cross-section (YZ plane) at III-III in FIG. 1. Further, FIG. 4 is a cross-sectional view showing the configuration of the fluid sterilization device in Embodiment 1, which shows a part (the first end portion 100a side) of the cross-section (XY plane) at IV-IV in FIG. 1. Further, FIG. 5 is a cross-sectional view showing the configuration of the fluid sterilization device in Embodiment 1, where FIG. 5(a) is a cross-section (YZ plane) at Va-Va in FIG. 1, and FIG. 5(b) is a cross-section (YZ plane) at Vb-Vb in FIG. 1.

[0019] The fluid sterilization device 1 in Embodiment 1 is a device that allows fluid to flow 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 within the range of having fluidity, it may be a mixture of gas and liquid, a mixture of gas and powdered solid, etc. In the case of a liquid, for example, it is water, oil, alcohol, a solution using these as solvents, etc.

[0020] 2. Details of each component of the fluid sterilization device 1 Next, each component of the fluid sterilization device 1 in Embodiment 1 will be described in detail.

[0021] 2-1. Structure 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 100a, the other end is the second end 100b, and among the two light source units 110, the one provided on the first end 100a side is the light source unit 110a, and the one provided on the second end 100b side is the light source unit 110b. Also, an inlet 101 is provided on the side wall of the first end 100a side of the flow path tube 100, and an outlet 102 is provided on the side wall of the second end 100b side. The inlet 101 and the outlet 102 are cylindrical and have a flow path region through which the fluid flows.

[0022] As shown in FIGS. 2 and 3, the central part of the flow path tube 100 is composed of a transparent tube 105, an aluminum film 106, and a light-shielding tube 107.

[0023] The transparent tube 105 is a cylindrical tube made of quartz. One end of the transparent tube 105 is connected to the first end 100a of the flow path tube 100, and the other end is connected to the second end 100b of the flow path tube 100. Therefore, the cylindrical flow path space is continuous from the first end 100a to the second end 100b through the transparent tube 105.

[0024] The material of the transparent tube 105 is not limited to quartz, and any material that can transmit ultraviolet light and has a low absorption rate is acceptable. For example, sapphire, ultraviolet-transmitting glass, fluororesin, acrylic resin, etc. may be used. In particular, a material with a small refractive index difference from water is preferred, and quartz in Embodiment 1 is suitable in this regard. For example, a material with a refractive index of 1.3 to 1.5 is preferred.

[0025] The thickness of the transparent tube 105 can be arbitrary as long as it has the strength to withstand water pressure and ultraviolet light transmittance. For example, it is 0.4 to 3.0 mm. For a material with a thickness where the ultraviolet light transmittance is 80% or more in the case of perpendicular incidence, it is preferred.

[0026] The inner peripheral surface of the transparent tube 105 is preferably as flat as possible. For example, the RMS (root mean square height) is preferably 1 μm or less. Bacteria are less likely to adhere to the unevenness of the inner peripheral surface, dirt is less likely to adhere to the inner peripheral surface, and a decrease in the sterilization efficiency can be suppressed. Also, the resistance of the inner wall surface decreases, and it becomes easier to maintain the flow. More preferably, it is 0.2 nm to 1.0 μm.

[0027] By forming a water-repellent film such as fluororesin on the inner peripheral surface of the transparent tube 105, the inner peripheral surface of the transparent tube 105 can be made to repel water, and dirt on the inner peripheral surface of the transparent tube 105 can be prevented. Also, a photocatalytic film that is excited by ultraviolet light and exhibits a photocatalytic effect can be formed on the inner peripheral surface of the transparent tube 105, and dirt on the inner peripheral surface of the transparent tube 105 can be suppressed by the photocatalytic film effect.

[0028] The aluminum film 106 is a strip-shaped flat film, which is wound cylindrically around the outer peripheral surface of the transparent tube 105 as shown in FIGS. 2 and 3, covering the entire outer peripheral surface of the transparent tube 105. Further, the aluminum films 106 are wound such that they partially overlap each other. In the overlapping region, the aluminum films 106 are adhered to each other by the adhesive layer 109, maintaining the cylindrical shape. Also, the aluminum film 106 is adhered to the first end portion 100a, the second end portion 100b of the flow path tube 100, the light shielding tube 107, etc. by the adhesive layer 109, and the position of the aluminum film 106 is fixed. In this way, since the adhesion of the aluminum film 106 is performed in a region not irradiated with ultraviolet light, it is possible to suppress the deterioration of the adhesive due to ultraviolet light. Note that the aluminum film 106 may be wound in multiple layers.

[0029] Further, the aluminum film 106 is made of aluminum or an alloy mainly composed of aluminum. Since aluminum is a material with a high reflectivity of ultraviolet light, by winding the aluminum film 106 around the transparent tube 105, the reflectivity of ultraviolet light can be easily increased.

[0030] Also, the aluminum film 106 is arranged so as not to be in contact with the entire outer peripheral surface of the transparent tube 105, and an air layer 104 exists between the transparent tube 105 and the aluminum film 106. By providing the air layer 104 in this way, reflection can be caused at the interface between the transparent tube 105 and the air layer 104 and at the interface between the air layer 104 and the aluminum film 106. As a result, the irradiation intensity of ultraviolet light on the fluid flowing inside the transparent tube 105 can be increased, and the sterilization efficiency can be improved.

[0031] The thickness of the aluminum film 106 is preferably 3 μm or more and 1 mm or less. Within this range, the reflectivity can be sufficiently improved, and it is also easy to wind around the transparent tube 105.

[0032] The thickness of the air layer 104 (the distance between the transparent tube 105 and the aluminum film 106) is preferably 0.1 μm or more and 1 mm or less. By setting it within this range, reflection can be efficiently caused at the interface between the transparent tube 105 and the air layer 104 and at the interface between the air layer

[0033] In Embodiment 1, the entire outer peripheral surface of the transparent tube 105 is not in contact with the aluminum film 106. However, at least a partial region does not need to be in contact with the aluminum film 106. It is preferable that 70% or more of the area of the outer peripheral surface of the transparent tube 105 is not in contact.

[0034] The light-shielding tube 107 is a cylindrical tube and is arranged to coaxially enclose the outside of the transparent tube 105. Further, the aluminum film 106 and the light-shielding tube 107 are arranged with a gap therebetween, and an air layer 108 exists. The light-shielding tube 107 is made of a material that does not transmit ultraviolet light. By providing the light-shielding tube 107 to shield ultraviolet light, leakage of ultraviolet light from the flow path tube 100 to the outside can be suppressed. Further, since the air layer 108 can cause reflection due to the refractive index difference, leakage of ultraviolet light can be further suppressed.

[0035] The light-shielding tube 107 is made of a material that absorbs ultraviolet light. For example, it is a material in which a carbon material such as carbon black, graphite, or carbon nanotube is mixed with a resin such as polypropylene, ABS, polyphenylene ether, polycarbonate, polyvinyl chloride, or polyacetal.

[0036] The materials of the first end portion 100a and the second end portion 100b of the flow path tube 100 are SUS (stainless steel), titanium, PTFE (polytetrafluoroethylene), etc. It may also be a structure in which the inner wall surface of a resin material resistant to ultraviolet light is covered with a material having a high ultraviolet light reflectance. The resin material resistant to ultraviolet light is, for example, vinyl chloride. Further, the material having a high ultraviolet light reflectance is aluminum, PTFE, etc. Also, 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 ultraviolet light reflectance. The material that transmits ultraviolet light is, for example, sapphire, ultraviolet light transmitting glass, fluororesin, acrylic resin, etc.

[0037] As shown in FIG. 5(a), the inlet 101 is disposed such that the inflow direction of the fluid flowing in through the inlet 101 is offset from the central axis O of the flow path pipe 100. That is, the flow path central axis L1 (hereinafter simply referred to as the central axis of the inlet 101), which is the central axis of the flow path region of the inlet 101, is parallel to a line intersecting the central axis O of the flow path pipe 100 and coincides with a direction that does not intersect the central axis O of the flow path pipe 100. When viewed in cross section as in FIG. 5(a), the central axis L1 of the inlet 101 is offset by Y1 in the Y direction so as not to pass through the central axis O of the flow path pipe 100. By offsetting the position of the inlet 101 in this manner, a spiral flow can be formed in the flow path space within the flow path pipe 100, and the tangential direction of the spiral flow is the central axis L1 of the inlet 101. Furthermore, as shown in FIG. 2, the angle between the central axis L1 of the inlet 101 and the central axis O is 90 degrees. Although it does not necessarily have to be 90 degrees, an angle of 80 to 100 degrees is preferable.

[0038] As shown in FIG. 5(b), the outlet 102 is also disposed such that its outflow direction is offset from the central axis O of the flow path pipe 100. That is, the flow path central axis L2 (hereinafter simply referred to as the central axis of the outlet 102), which is the central axis of the flow path region of the outlet 102, is parallel to a line intersecting the central axis O of the flow path pipe 100 and coincides with a direction that does not intersect the central axis O of the flow path pipe 100. When viewed in cross section as in FIG. 5(b), the central axis L2 of the outlet 102 is offset by Y2 in the Y direction so as not to pass through the central axis O of the flow path pipe 100. This allows the spiral flow to be maintained even 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 are preferably as close as possible, and are particularly preferably the same.

[0039] 2-2. Configuration of the light source unit 110 The light source unit 110 has an LED package 140, a pillar portion 120, and a storage portion 130. The light source unit 110a provided on the first end portion 100a side will be described below, but the light source unit 110b provided on the second end portion 100b side has the same configuration.

[0040] As shown in FIG. 2, the column portion 120 protrudes from the first end of the flow path pipe 100 toward the second end side and has a frustum-shaped portion. The central axis of the column portion 120 coincides with the central axis of the flow path pipe 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 of the column portion 120 on the thicker diameter side is connected to the first end of the flow path pipe 100, and one end of the column portion 120 on the thinner diameter side is connected to the storage portion 130.

[0041] Note that the shape of the column portion 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 frustum of a pyramid shape may be used. However, a frustum shape is preferred for forming a spiral flow. Also, the entire column portion 120 does not have to be a frustum, and a part of it 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 portion 130 may be cylindrical, and the other part may be frustum-shaped.

[0042] The storage portion 130 is connected to the tip of the column portion 120. The storage portion 130 stores the LED package 140. The storage portion 130 includes a glass plate 132, a pedestal portion 133, and a substrate 135.

[0043] The pedestal portion 133 is a cylindrical box shape with an open top surface, and the outer bottom surface is connected to the tip of the column portion 120. The substrate 135 is disposed 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 contamination. The glass plate 132 is not limited to a flat plate and may be lens-shaped. For example, a TIR lens, a fly-eye lens, a Fresnel lens, etc. may be used.

[0044] 2, the base portion 133 is formed so as to extend from the tip of the pillar portion 120 to the outside in the radial direction of the pillar portion 120, around the entire circumference of the tip of the pillar portion 120. Therefore, the back surface of the base portion 133 comes into contact with the flow path space, except for the region connected to the pillar portion 120.

[0045] The base portion 133 has a peripheral wall 136 that protrudes toward the first end in the outer peripheral region of its back surface, and has a recess 134 that is surrounded by the back surface of the base portion 133 and the peripheral wall 136. In the first embodiment, the peripheral wall 136 does not need to be provided around the entire circumference, and it is preferable to provide it partially. If it is provided around the entire circumference, air will accumulate in the recess 134, reducing cooling efficiency. Furthermore, it is preferable that the peripheral wall 136 be provided outside the LED package 140 when viewed from the central axis direction of the flow path pipe 100. In other words, it is preferable that the LED package 140 is located within the region of the recess 134. This allows the base portion 133 to be cooled more efficiently.

[0046] In the first embodiment, the base 133 is a cylindrical box, but any box shape is acceptable. For example, it may be a square prism-shaped box (box-shaped). However, in order to generate a spiral flow, it is preferable to use a cylindrical box shape as in the first embodiment.

[0047] Titanium is used as the material for the column portion 120 and the base portion 133. Other than titanium, for example, metal materials with high thermal conductivity such as SUS and aluminum, or high heat dissipation resins mixed with thermally conductive fillers can be used.

[0048] The LED package 140 is mounted on the substrate 135. A plurality of LED packages 140 may be mounted, and two are mounted in Fig. 2. The LED package 140 has an LED, a substrate on which the LED is mounted, and a lens that seals the LED.

[0049] 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 that has high sterilization efficiency. A single LED package 140 may be provided with a plurality of LEDs.

[0050] When viewed from the central axis direction of the flow path tube 100, the LED package 140 is preferably mounted in a region outside the pillar portion 120. 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.

[0051] In the first embodiment, the packaged LED package 140 is mounted on the substrate 135, but the LED may be directly mounted on the substrate 135.

[0052] A continuous through hole 111 is provided at the center of the pillar portion 120 and the storage portion 130. This hole 111 is a hole through which a wiring cable for supplying 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.

[0053] 3. Regarding the fluid flow path The flow path of the fluid flowing in the flow path tube 100 will be described with reference to FIG. 6. FIG. 6(a) is a diagram schematically showing the flow path on the first end portion 100a side (inlet 101 side) of the flow path tube 100, and FIG. 6(b) is a diagram schematically showing the flow path on the second end portion 100b side (outlet 102 side) of the flow path tube 100.

[0054] As shown in FIG. 6(a), the fluid that has entered the flow path space in the flow path tube 100 from the inlet 101 flows around the pillar 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 pillar portion 120. When viewed in the direction of the central axis O of the flow path tube 100, from the first end portion 100a toward the second end portion 100b, the fluid flows in a counterclockwise rotation.

[0055] The fluid that circulates around the column portion 120 hits the side surface of the frustum-shaped portion of the column portion 120. Therefore, due to the inclination of the side surface, the fluid is reflected in the axial direction, and a flow path is formed toward the storage portion 130. As a result, the fluid can be efficiently brought into contact with the storage portion 130, and the cooling efficiency can be improved.

[0056] Further, 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 contacts the region of the back surface of the pedestal portion 133 that hits directly below the LED package 140. Therefore, the pedestal portion 133 can be efficiently cooled.

[0057] In addition, since a peripheral wall 136 is provided on the back surface of the pedestal portion 133 and a recess 134 surrounded by the peripheral wall 136 exists, 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.

[0058] 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 tube 100. As a result, a spiral flow F1 is formed. By forming the spiral flow F1, the residence time of the fluid in the flow path space becomes longer, and the irradiation time of ultraviolet light on the fluid becomes longer, so that the sterilization efficiency can be improved.

[0059] On the other hand, on the second end portion 100b side, as shown in FIG. 6(b), a 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.

[0060] Also, also on the second end portion 100b side, 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, the 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 so as 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.

[0061] 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 leading to 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.

[0062] 5. Summary As described above, in the fluid sterilization device according to Embodiment 1, the flow path tube 100 has the transparent tube 105 and the aluminum film 106 wound around the transparent tube 105. Therefore, the ultraviolet light reflectance of the inner wall surface of the flow path tube 100 can be improved simply and at low cost.

[0063] (Modification 1 of Embodiment 1) FIG. 7 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. 7(a), the light source portion 210 has a column portion 120 and a housing portion 230. The column portion 120 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.

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

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

[0066] FIGS. 7(b) and 7(c) are cross-sectional views showing the cross-section at VI-VI in FIG. 7(a). FIG. 7(b) shows the case where a spiral groove 237 is provided on the back surface of the pedestal unit 233. The center of the spiral is the center of the column unit 220. By providing such a spiral groove 237, the contact time between the fluid and the storage unit 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 unit 230, and the fluid passing between the inner wall of the flow path tube 100 and the storage unit 230 is likely to form a spiral flow.

[0067] FIG. 7(c) shows the case where a radial groove 237 is provided on the back surface of the pedestal unit 233. By providing such a groove 237, the fluid can be guided to the outer periphery.

[0068] In the light source unit 210 on the outlet 102 side as well, a groove 237 may be provided as shown in FIGS. 7(b) and 7(c). The storage unit 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 unit 230 can be guided to the column unit 220 side, and then a smooth flow path can be formed toward the outlet 102 side by reflection by the column unit 220.

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

[0070] (Third modification 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 back surface of the storage portion 130 cannot be cooled by contacting it with a fluid, 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 center of the flow path tube 100. The light intensity sensor is a sensor that detects the intensity of ultraviolet light at the center of 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 center 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 center of the flow path tube 100.

[0073] (Modification 5 of Embodiment 1) A spiral groove may be provided on the inner wall of the flow path tube 100. By providing the spiral groove 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] (Modification 6 of Embodiment 1) Modification 6 of Embodiment 1 is obtained by modifying the flow path tube 100 in Embodiment 1 as follows. FIG. 8 is a cross-sectional view of the flow path tube 100 in Modification 6 of Embodiment 1, and FIG. 9 is a plan view of the aluminum film 106 in a flat state before being wound around the transparent tube 105.

[0075] As shown in FIG. 9, an adhesive layer 209 is provided on the inner surface of the aluminum film 106 (the main surface that faces the transparent tube 105 when the aluminum film 106 is wrapped around the transparent tube 105). The adhesive layer 209 is not provided over the entire surface, but has a periodic pattern. In other words, the pattern is one in which areas where the adhesive layer 209 is provided and areas where the adhesive layer 209 is not provided appear alternately. The periodic pattern may be a one-dimensional periodic pattern or a two-dimensional periodic pattern, such as a striped pattern as shown in FIG. 9(a) or a pattern in which dots are arranged in a grid pattern as shown in FIG. 9(b). The dots may have any shape, such as a circle or a regular polygon.

[0076] The pattern of the adhesive layer 209 does not necessarily have to be periodic, but may be a pattern having regions where the adhesive layer 209 is provided and regions where the adhesive layer 209 is not provided.

[0077] The aluminum film 106 is wrapped cylindrically around the entire outer surface of the transparent tube 105, and the transparent tube 105 and the aluminum film 106 are bonded together via an adhesive layer 209. Here, because the adhesive layer 209 has a periodic pattern, there are areas on the surface of the aluminum film 106 where the adhesive layer 209 is not present, and in these areas the transparent tube 105 and the aluminum film 106 do not come into contact, creating an air layer 104. In other words, the air layer 104 exists around the adhesive layer 209. By forming the adhesive layer 209 in this periodic pattern, the aluminum film 106 can be bonded to the transparent tube 105 while the adhesive layer 209 functions as a spacer to form the air layer 104.

[0078] The pattern of the adhesive layer 209 is preferably such that the ratio of the area of the adhesive layer 209 to the surface area of the aluminum film 106 is 3 to 30%. By using such a pattern, the aluminum film 106 can be bonded to the transparent tube 105 with sufficient strength, and the area of the air layer 104 can also be made sufficiently large.

[0079] Note that an adhesive layer 209 with a similar pattern may also be provided on the outer surface of the aluminum film 106 (the main surface on the light-shielding tube 107 side when the aluminum film 106 is wound around the transparent tube 105), and the aluminum film 106 and the inner peripheral surface of the light-shielding tube 107 may be adhered via the adhesive layer 209. While forming an air layer 108 between the aluminum film 106 and the light-shielding tube 107, the position of the aluminum film 106 with respect to the light-shielding tube 107 can be fixed.

[0080] (Modification 7 of Embodiment 1) Modification 7 of Embodiment 1 is obtained by modifying the flow path tube 100 in Embodiment 1 as follows. FIG. 10 is a cross-sectional view of the flow path tube 100 in Modification 7 of Embodiment 1. As shown in FIG. 10, the aluminum film 106 is wound in a cylindrical shape such that it is C-shaped in a cross-section perpendicular to the axis, the transparent tube 105 and the aluminum film 106 are arranged at a predetermined interval, and an air layer 104 exists. Further, the inner peripheral surface of the light-shielding tube 107 has a convex portion 107a that protrudes inward. This convex portion 107a is fitted into the gap of the aluminum film 106. The displacement of the aluminum film 106 can be suppressed by the convex portion 107a.

[0081] (Other Modifications) In the fluid sterilization device in the embodiment, light source units 110a and 110b are provided on the inlet 101 side and the outlet 102 side, respectively. 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 arrange a reflective film 160 that reflects the light from the light source unit 110a on the end surface on the second end side. The light from the light source unit 110a can be reflected by the reflective film 160, and the sterilization efficiency can be improved by irradiating the fluid with the reflected light.

[0082] Alternatively, the light source unit 110 may be provided only on the outlet 102 side. Similarly in this case, the sterilization efficiency can be improved by providing the reflective film 160 on the end surface on the first end side.

Description of Reference Numerals

[0083] 100: Flow path tube 101: Inlet 102: Outlet 105: Transparent tube 106: Aluminum film 107: Light-shielding tube 108, 108a, 108b: Air layer 110, 110a, 110b, 210: Light source part 111: Hole 120: Column part 130: Storage part 132: Glass plate 133: Base part 134: Concave part 135: Substrate 136: Peripheral wall 140: LED package

Claims

1. A fluid sterilization device having a cylindrical flow path tube through which a fluid flows and a light source unit that irradiates ultraviolet light inside the flow path tube, wherein the flow path tube, comprises a transparent tube that transmits the ultraviolet light, and an aluminum film wound around the outer peripheral surface of the transparent tube, wherein the aluminum film is arranged so as not to be in close contact with at least a partial region of the outer peripheral surface of the transparent tube and has a first air layer. Fluid sterilization device.

2. The fluid sterilization device according to claim 1, wherein the aluminum films are wound so as to overlap each other and have an adhesive layer between the aluminum films.

3. The fluid sterilization device according to claim 1 or claim 2, wherein the aluminum film is arranged so as to have the first air layer between the entire outer peripheral surface of the transparent tube.

4. The fluid sterilization device according to claim 1, wherein a partial region of the inner surface of the aluminum film has an adhesive layer, the transparent tube and the aluminum film are adhered by the adhesive layer, and the first air layer exists around the adhesive layer.

5. The fluid sterilization device according to claim 4, wherein the adhesive layer has a periodic pattern.

6. The fluid sterilization device according to claim 1, wherein the flow path tube further comprises a light-shielding tube that covers the outer periphery of the aluminum film and shields the ultraviolet light from the light source unit.

7. The fluid sterilization device according to claim 6, having a second air layer between the aluminum film and the light-shielding tube.

8. The aluminum film is wound in a C-shaped cylindrical shape in a cross-section perpendicular to the axis, the light-shielding tube has a convex portion protruding inward on its inner peripheral surface, and the convex portion is fitted into the gap of the aluminum film in the shape of C. The fluid sterilization device according to claim 6 or claim 7.

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