Fluid sterilizer

Abstract

To provide a fluid sterilizer having enhanced sterilization effect.SOLUTION: A fluid sterilizer includes: a flow passage pipe 100, which is formed shaped like a cylinder defining a flow passage space for fluid passage and which has an inlet 101 formed near a first end and an outlet 102 formed near a second end; a first light source unit 110A located near the inlet 101 and emitting ultraviolet light toward the second end side; and a second light source unit 110B located near the outlet 102 and emitting ultraviolet light toward the first end side. The flow passage pipe 100 is shaped to be narrow in the middle along the axial direction of the flow passage space.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 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, when using a mercury lamp, there is also a problem that the sterilization device becomes large. Therefore, the replacement of the mercury lamp with an ultraviolet LED is in progress.

[0003] As a fluid sterilization device using an ultraviolet LED, there is Patent Document 1. Patent Document 1 discloses a configuration in which a columnar light source portion protruding from one end of a flow path tube toward the other end side and a columnar light source portion protruding from the other end of the flow path tube toward the one end side are provided, and these two light source portions are arranged facing each other with the internal space of the flow path tube interposed therebetween. It is described that the sterilization efficiency of running water is improved by sterilizing the running water flowing through the internal space of the flow path tube with the two light source portions.

[0004] Further, Patent Document 1 also describes that by forming the flow path tube of polytetrafluoroethylene, the ultraviolet rays irradiated from the light source are repeatedly reflected on the inner wall surface of the flow path tube to improve the sterilization efficiency of running water.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the structure of Patent Document 1, a flow path tube is formed of polytetrafluoroethylene having a high ultraviolet reflectance. However, when attempting to improve the sterilization efficiency of running water by increasing the reflectance of the flow path tube itself, the materials that can be selected as the material of the flow path tube are limited, and the degree of freedom in selecting the material of the flow path tube is reduced. Further, even if the reflectance of the flow path tube itself is increased, if dirt contained in the running water adheres to the inside of the flow path tube, the reflectance will decrease. In particular, when polytetrafluoroethylene is machined, irregularities of several micrometers are formed on the inner surface, so dirt easily adheres. For these reasons, there is a demand to improve the sterilization efficiency of running water without using a material having a high ultraviolet reflectance for the flow path tube.

[0007] The present invention has been made in view of such a background, and aims to provide a fluid sterilization device with an improved sterilization effect.

Means for Solving the Problems

[0008] One aspect of the present invention is a flow path tube formed in a cylindrical shape that forms a flow path space through which a fluid flows, having an inlet formed near the first end and an outlet formed near the second end; a first light source unit disposed near the inlet and irradiating ultraviolet light toward the second end side; a second light source unit disposed near the outlet and irradiating ultraviolet light toward the first end side, and the flow path tube is formed such that an intermediate portion in the axial direction of the flow path space is constricted and narrowed, in a fluid sterilization device.

Effects of the Invention

[0009] In the fluid sterilization device of the above aspect, since the fluid concentrates and flows in the constricted and narrowed portion of the flow path space, ultraviolet light can be effectively irradiated to the fluid in the constricted and narrowed portion of the flow path space. Therefore, the sterilization effect can be improved.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0011] The fluid sterilization device includes a flow path pipe formed in a cylindrical shape that forms a flow path space through which the fluid flows, and has an inlet formed near the first end and an outlet formed near the second end. It also includes a first light source unit disposed near the inlet that irradiates ultraviolet light toward the second end side, and a second light source unit disposed near the outlet that irradiates ultraviolet light toward the first end side. The flow path pipe is formed such that an intermediate portion in the axial direction of the flow path space is constricted and becomes narrower.

[0012] According to this, since the fluid concentrates and flows in the constricted and narrower portion of the flow path space, ultraviolet light can be effectively irradiated to the fluid at the constricted and narrower portion of the flow path space. Therefore, the sterilization effect can be improved.

[0013] In the above fluid sterilization device, the flow path pipe has a first large-diameter portion located near the first end where the inlet is formed, a second large-diameter portion located near the second end where the outlet is formed, and a small-diameter portion formed between the first large-diameter portion and the second large-diameter portion and having a smaller diameter than the first large-diameter portion and the second large-diameter portion. This forms a constricted and narrower portion in the middle of the flow path space.

[0014] In the above fluid sterilization device, since the first large-diameter portion, the second large-diameter portion, and the small-diameter portion are coaxially arranged with each other, the fluid can be effectively concentrated and flowed through the constricted and narrower portion of the flow path space.

[0015] In the above-described fluid sterilization device, the small-diameter portion has a first tapered portion that gradually decreases in diameter from the first large-diameter portion side toward the second large-diameter portion side, and a second tapered portion that gradually decreases in diameter from the second large-diameter portion side toward the first large-diameter portion side. Thereby, even if the middle of the flow path space is constricted and becomes narrow, the flow of the fluid in the flow path space can be made smooth.

[0016] In the above-described fluid sterilization device, the optical axis of the first light source portion and the optical axis of the second light source portion pass through the small-diameter portion without intersecting the inner wall of the flow path tube. Thereby, since ultraviolet light can be concentrated and irradiated on the constricted and narrow portion of the flow path space, the sterilization effect can be further improved.

[0017] In the above-described fluid sterilization device, the inlet is arranged such that the inflow direction of the inflowing fluid is offset with respect to the center of the flow path tube. Thereby, since the fluid flowing in from the inlet forms a spiral flow, 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. As a result, the sterilization efficiency can be improved.

[0018] In the above-described fluid sterilization device, the flow path tube is formed of a material including one selected from the group consisting of stainless steel, titanium, polyvinyl chloride, polyethylene, and quartz. When a material with a high reflectivity of ultraviolet light is not used for the flow path tube in this way, it is difficult for the intensity of ultraviolet light to be uniform over the entire flow path space. However, by constricting and narrowing the middle of the flow path space, both the fluid and ultraviolet light can be concentrated on the constricted and narrow portion. Therefore, the sterilization effect can be improved even if a material with a high reflectivity of ultraviolet light is not used for the flow path tube.

[0019] (Embodiment) 1. Outline of the configuration of the fluid sterilization device 1 FIG. 1 is a diagram schematically showing the configuration of the fluid sterilization device 1 in the present embodiment. As shown in FIG. 1, the fluid sterilization device in the present embodiment has a flow path tube 100 and a light source portion 110. Further, the light source portion 110 has an LED package 140, a column portion 120, and a storage portion 130.

[0020] In the fluid sterilization device 1 of the present embodiment, fluid is flowed from the inlet 101 of the flow path pipe 100 into the flow path space inside the flow path pipe 100, the fluid is irradiated with ultraviolet light from the light source unit 110 to sterilize the fluid, and the sterilized fluid is discharged 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, water, oil, alcohol, a solution using these as a solvent, etc.

[0021] 2. Details of each component of the fluid sterilization device 1 Next, each component of the fluid sterilization device 1 will be described in detail.

[0022] 2-1. Configuration of the flow path pipe 100 The flow path pipe 100 is cylindrical and has a cylindrical space inside. This space is the flow path space through which the fluid to be sterilized flows. The material of the flow path pipe 100 is a metal such as stainless steel, titanium, aluminum, iron, a resin material such as polyvinyl chloride, polyethylene, or PTFE (polytetrafluoroethylene), or a glass such as quartz glass.

[0023] Stainless steel, titanium, iron, and polyvinyl chloride are materials with a high absorption rate of ultraviolet light and a low reflectivity of ultraviolet light compared to materials with a high reflectivity of ultraviolet light such as aluminum and PTFE (polytetrafluoroethylene). Stainless steel and titanium are materials with high corrosion resistance to seawater. Glass is, for example, quartz glass, soda-lime glass, borosilicate glass, lead glass, etc., and is a material that is transparent to ultraviolet light and has a low reflectivity of ultraviolet light. In the case of a material with a low reflectivity of ultraviolet light as the material of the flow path pipe 100, for example, the reflectivity of ultraviolet light on the surface in contact with the fluid to be sterilized is 35% or less.

[0024] One light source unit 110 is provided at each of both ends of the flow path tube 100. Further, an inlet 101 is provided in a side wall on one (left side in FIG. 1) end side in the axial direction of the flow path tube 100, and an outlet 102 is provided in a side wall on the other (right side in FIG. 1) end side. Hereinafter, the end on the inlet 101 side of the flow path tube 100 is referred to as the first end, and the end on the outlet 102 side of the flow path tube 100 is referred to as the second end.

[0025] Of the light source units 110 arranged at both ends of the flow path tube 100, the light source unit arranged closer to the inlet 101 is the first light source unit 110A, and the light source unit arranged closer to the outlet is the second light source unit 110B. Hereinafter, the first light source unit 110A and the second light source unit 110B are simply referred to as the light source unit 110 without distinguishing their names.

[0026] FIG. 2(a) is a diagram showing the position of the inlet 101, and FIG. 2(b) is a diagram showing the position of the outlet 102. FIGS. 2(a) and 2(b) are cross-sectional views of a cross-section cut along a plane perpendicular to the central axis of the flow path tube 100, viewed from the first end side toward the second end side.

[0027] As shown in FIG. 2(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 center O of the flow path tube 100. That is, the central axis L1 of the inlet 101 is displaced so as not to pass through the center 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 in the flow path tube 100 as shown in FIG. 3. The tangential direction of the spiral flow on the central axis L1 of the inlet 101 is the direction of the central axis L1 of the inlet 101.

[0028] The outlet 102 is also arranged such that the outflow direction is offset with respect to the center O of the flow path tube 100, as shown in FIG. 2(b). That is, the central axis L2 of the outlet 102 is displaced so as not to pass through the center 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 on the central axis L2 of the outlet 102 is the direction of the central axis L2 of the outlet 102.

[0029] As shown in Fig. 1, the flow path tube 100 has a shape with a constriction in the middle in the axial direction (the left - right direction in Fig. 1), becoming thinner. Specifically, the flow path tube 100 has a first large - diameter portion 103, a second large - diameter portion 104, and a small - diameter portion 105. The first large - diameter portion 103 is located near the first end of the flow path tube 100. An inlet 101 is formed in the first large - diameter portion 103. The second large - diameter portion 104 is located near the second end of the flow path tube 100. An outlet 102 is formed in the second large - diameter portion 104.

[0030] The small - diameter portion 105 is formed between the first large - diameter portion 103 and the second large - diameter portion 104, and has a smaller diameter than the first large - diameter portion 103 and the second large - diameter portion 104. The first large - diameter portion 103, the second large - diameter portion 104, and the small - diameter portion 105 are coaxially arranged with each other.

[0031] The small - diameter portion 105 has a minimum - diameter portion 105a, a first tapered portion 105b, and a second tapered portion 105c. The minimum - diameter portion 105a is the portion with the smallest diameter among the small - diameter portion 105. The first tapered portion 105b is formed between the first large - diameter portion 103 and the minimum - diameter portion 105a, and gradually reduces in diameter from the first large - diameter portion 103 toward the minimum - diameter portion 105a. The second tapered portion 105c is formed between the second large - diameter portion 104 and the minimum - diameter portion 105a, and gradually reduces in diameter from the second large - diameter portion 104 toward the minimum - diameter portion 105a.

[0032] Since the wall thickness of the flow path tube 100 is configured to be substantially constant, the flow path space also has a shape with a constriction in the middle in the axial direction, becoming thinner. In other words, a constricted portion 106 that is constricted and thinned is formed in the middle of the flow path space in the axial direction.

[0033] In this embodiment, the small - diameter portion 105 of the flow path tube 100 has a shape that is symmetric with respect to the axial direction of the flow path tube 100 (left - right symmetric in Fig. 1). Therefore, the constricted portion 106 of the flow path space also has a shape that is symmetric with respect to the axial direction of the flow path tube 100 (left - right symmetric in Fig. 1).

[0034] 2 - 2. Configuration of the light source unit 110 The light source unit 110 has a column part 120, a storage part 130, and an LED package 140. The storage part 130 stores the LED package 140. Hereinafter, the light source unit 110 provided on the first end side will be described, but the light source unit 110 provided on the second end side has the same configuration.

[0035] As shown in FIG. 1, the column part 120 protrudes in the axial direction of the flow path pipe 100 from the first end side to the second end side of the flow path pipe 100 and has a frustum-shaped portion. The central axis of the column part 120 coincides with the central axis of the flow path pipe 100. That is, the central axis of the column part 120 is arranged coaxially with the central axis of the flow path pipe 100.

[0036] The inclination angle (angle with respect to the bottom surface) of the side surface of the frustum is, for example, 30 to 70°. The end on the larger diameter side of the column part 120 is connected to the first end of the flow path pipe 100, and the end on the smaller diameter side is connected to the storage part 130.

[0037] 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 frustum of a 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 portion of the column part 120 connected to the storage part 130 may be cylindrical, and the base side portion connected to the first end of the flow path pipe 100 may be frustum-shaped.

[0038] As shown in FIG. 4, the storage part 130 that stores the LED package 140 has a glass plate 132, a pedestal part 133, and a mounting substrate 135.

[0039] The pedestal portion 133 is a bottomed cylindrical member with an open front end surface, and the bottom surface is connected to the tip of the column portion 120. The central axis of the pedestal portion 133 coincides with the central axis of the column portion 120. That is, the central axis of the pedestal portion 133 is arranged coaxially with the central axis of the column portion 120. As described above, the central axis of the column portion 120 is arranged coaxially with the central axis of the flow path pipe 100. Therefore, the central axis of the pedestal portion 133 is also arranged coaxially with the central axis of the flow path pipe 100.

[0040] In the internal space of the pedestal portion 133, a mounting substrate 135 is arranged at the bottom, and an LED package 140 is mounted on the mounting substrate 135. A glass plate 132 is provided on the front end surface of the pedestal portion 133 to seal the internal space of the pedestal portion 133. The glass plate 132 is a material that transmits ultraviolet light from the LED package 140, for example, quartz or sapphire. By providing a photocatalyst film that transmits ultraviolet light on the surface of the glass plate 132, it is possible to suppress the propagation of germs on the glass plate 132 and 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.

[0041] 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. That is, the outer diameter of the pedestal portion 133 is larger than the outer diameter of the tip of the column portion 120. Therefore, the bottom surface of the pedestal portion 133 is exposed to the flow path space except for the region connected to the column portion 120.

[0042] A peripheral wall 136 protruding toward the first end side is formed at the outer edge portion of the bottom surface of the pedestal portion 133. As a result, a recessed portion 134 recessed more than the peripheral wall 136 is formed in the portion of the bottom surface of the pedestal portion 133 surrounded by the peripheral wall 136. The recessed portion 134 is provided to retain fluid as much as possible near the bottom surface of the pedestal portion 133. The pedestal portion 133 can be cooled by the fluid staying near the bottom surface of the pedestal portion 133. That is, the heat-generating LED package 140 can be cooled via the pedestal portion 133.

[0043] In this embodiment, the peripheral wall 136 is provided over the entire circumference of the bottom surface of the pedestal portion 133, but it may be provided only on a part of the bottom surface of the pedestal portion 133. By providing the peripheral wall 136 only on a part of the bottom surface of the pedestal portion 133, the formation of an air pocket in the recess 134 can be suppressed and the cooling efficiency can be improved.

[0044] 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, when viewed in the central axis direction of the flow path pipe 100, it is preferable that the recess 134 is located at a position overlapping the LED package 140. The fluid staying near the bottom surface of the pedestal portion 133 can cool the pedestal portion 133 more efficiently. That is, the heat-generating LED package 140 can be cooled more efficiently via the pedestal portion 133.

[0045] In this embodiment, the pedestal portion 133 is a bottomed cylindrical member, but any member having a bottomed cylindrical shape may be used. For example, it may be a bottomed square cylindrical (polygonal box-shaped) member. However, from the viewpoint of generating a spiral flow, it is preferable to have a bottomed cylindrical shape as in this embodiment.

[0046] The materials of the column portion 120 and the pedestal portion 133 are preferably metal materials with high thermal conductivity such as stainless steel and aluminum. Titanium may be used as the material of the column portion 120 and the pedestal portion 133, and the surface may be oxidized to form a photocatalytic film. According to this, the propagation of germs on the column portion 120 and the pedestal portion 133 can be suppressed.

[0047] The LED package 140 is mounted on the mounting substrate 135. A plurality of LED packages 140 may be mounted on one mounting substrate 135, and two are mounted in FIGS. 1 and 4. As shown in FIG. 4, the LED package 140 includes an LED 141, an LED substrate 142 on which the LED 141 is mounted, and a lens 143 that seals the LED 141.

[0048] LED141 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. In FIG. 4, one LED141 is shown in one LED package 140, but a plurality of LED141s may be provided in one LED package 140. The configuration of LED141 is not limited, and it may be either a face-up type or a flip-chip type.

[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 fluid can be brought into contact with the region on the axial extension of the LED package 140 on the bottom surface of the pedestal portion 133, the storage portion 130 can be efficiently cooled. That is, the heat-generating LED package 140 can be efficiently cooled.

[0050] In this embodiment, the LED package 140 having the LED141 is mounted on the mounting substrate 135, but the LED141 may be directly mounted on the mounting substrate 135.

[0051] A hole 111 penetrating in the axial direction is provided in the central portions of the column portion 120 and the storage portion 130. The 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 135 passes. The wiring cable is drawn into the mounting substrate 135 through the hole 111.

[0052] The mounting substrate 135 is a substrate on which the LED package 140 is mounted. In this embodiment, the mounting substrate 135 is formed of aluminum. The mounting substrate 135 may be a glass epoxy substrate such as FR-4 or CEM3, or a flexible substrate made of polyimide or the like. Various processes such as drilling may be performed on the mounting substrate 135.

[0053] As shown in FIG. 4, the mounting surface of the mounting substrate 135 on which the LED package 140 is mounted is formed in a planar shape perpendicular to the central axis of the pedestal portion 133. In the present embodiment, on the mounting surface of the mounting substrate 135, two LED packages 140 are arranged at equal intervals along a virtual circle centered on the central portion of the mounting surface.

[0054] A circuit forming member (not shown) electrically connected to the LED package 140 is mounted on the mounting substrate 135. The circuit forming member is a drive circuit for causing the LED 141 to emit light, a connector header for connecting the drive circuit and a power cable, and the like. As other electronic components (not shown), a thermistor for measuring the temperature of the mounting substrate 135, a connector header for connecting the thermistor and a power cable, and the like are provided on the mounting substrate 135.

[0055] 2-3. Optical axis 144 of LED141 The optical axis 144 of the LED 141 is, in the ultraviolet light emitted by the LED 141, the axis in the stacking direction of the semiconductor layers for emitting ultraviolet light, that is, the axis perpendicular to the main surface of the element substrate on which the semiconductor layers are stacked. The optical axis 144 is, for example, an axis located at the center in the irradiation range of the ultraviolet light of the LED 141 having a predetermined light distribution characteristic.

[0056] The optical axis 144 may be a virtual line extending in the direction in which the luminous intensity of the ultraviolet light is maximized from the LED 141 in the irradiation range of the ultraviolet light, but is not limited to this depending on the configuration of the LED 141. In the present embodiment, the optical axis 144 of the LED 141 is on the perpendicular line to the portion of the mounting surface where the LED 141 is mounted.

[0057] As described above, the mounting surface of the mounting substrate 135 is formed in a planar shape perpendicular to the central axis of the pedestal portion 133. Therefore, the optical axis 144 of the LED 141 is parallel to the central axis of the pedestal portion 133.

[0058] As described above, the central axis of the pedestal portion 133 is arranged coaxially with the central axis of the flow path tube 100. Therefore, the optical axis 144 of the LED 141 is parallel to the central axis of the flow path tube 100.

[0059] In the present embodiment, as shown in FIG. 1, the position of the light source unit 110 is set so that the optical axis 144 of the LED 141 passes through the small-diameter portion 105 of the flow path tube 100 without intersecting the inner wall of the flow path tube 100. Specifically, the position of the light source unit 110 is set so that the LED 141 overlaps with the constriction portion 106 of the flow path space when viewed from the axial direction (the left-right direction in FIG. 1) of the flow path tube 100.

[0060] 3. Regarding the flow path of the fluid Next, the flow path of the fluid in the flow path space will be described. FIG. 3 is a diagram schematically showing the flow path of the fluid in the vicinity of the first end of the flow path tube 100. As shown in FIG. 3, the fluid that has entered the flow path space in the flow path tube 100 from the inlet 101 hits the side surface of the frustum-shaped portion of the column portion 120. However, since the side surface is inclined, it is reflected in the axial direction, and a flow 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.

[0061] Since the outer diameter of the pedestal portion 133 is larger than the outer diameter of the tip of the column portion 120, the fluid can be brought into contact with the bottom surface of the pedestal portion 133 (the left side surface in FIG. 3). In particular, among the bottom surface of the pedestal portion 133, the fluid contacts the region on the axial extension of the LED package 140. Therefore, the pedestal portion 133 can be efficiently cooled.

[0062] Since the peripheral wall 136 is provided on the bottom 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 bottom surface of the pedestal portion 133 to the fluid, and the cooling efficiency can be improved.

[0063] Since the inflow port 101 is offset, as shown in FIG. 3, a flow that swirls around the column portion 120 is formed. Since the column portion 120 has a shape that becomes thinner from the first end side to the second end side, the fluid flows axially from the first end side to the second end side while swirling around the column portion 120. Therefore, a spiral flow is formed in the flow path space. By making it a spiral flow, 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.

[0064] Moreover, a constricted portion 106 that is constricted and becomes thinner is formed in the middle of the flow path space, and the optical axes 144 of the respective LEDs 141 are set to face the constricted portion 106. Therefore, the fluid in the flow path space flows concentratedly into the constricted portion 106, and ultraviolet light is concentratedly irradiated on the fluid in the constricted portion 106. That is, both the fluid and the ultraviolet light are concentrated in the constricted portion 106. Therefore, since the fluid in the flow path space is efficiently irradiated with ultraviolet light, the sterilization efficiency can be improved.

[0065] Furthermore, when the material of the flow path tube 100 is glass, due to the difference in refractive index between air and glass, the ultraviolet light from the light source unit 110 is totally reflected by the flow path tube 100 (particularly the first tapered portion 105b and the second tapered portion 105c). Therefore, the ultraviolet light is further concentrated in the constricted portion 106, and a further improvement in sterilization efficiency can be achieved.

[0066] In the light source unit 110 on the side of the outflow port 102, since the column portion 120 has a shape that becomes thinner from the second end side to the first end side, the fluid flowing from the first end side to the second end side can be reflected in the radial direction of the flow path tube 100 by the column portion 120. Therefore, the residence time of the fluid can be lengthened in the vicinity of the storage portion 130 on the side of the outflow port 102, so that the storage portion 130 can be efficiently cooled.

[0067] 5. Summary of Effects As described above, according to the fluid sterilization device in the present embodiment, in the flow path tube 100, the constriction 106 in the middle of the flow path space is constricted and narrowed, so that the fluid concentrates and flows through the constriction 106. Therefore, ultraviolet light can be effectively irradiated to the fluid at the constriction 106, improving the sterilization effect.

[0068] Specifically, the flow path tube 100 has a first large-diameter portion 103 near the first end, a second large-diameter portion 104 near the second end, and a small-diameter portion 105 between the first large-diameter portion 103 and the second large-diameter portion 104, thereby forming a constriction 106 in the flow path space.

[0069] Since the first large-diameter portion 103, the second large-diameter portion 104, and the small-diameter portion 105 are coaxially arranged with each other, the fluid can be effectively concentrated and flowed through the constriction 106.

[0070] The small-diameter portion 105 has a first tapered portion 105b that gradually reduces in diameter from the first large-diameter portion 103 side toward the second large-diameter portion 104 side, and a second tapered portion 105c that gradually reduces in diameter from the second large-diameter portion 104 side toward the first large-diameter portion 103 side. Thereby, even if a constriction 106 that is constricted and narrowed is formed in the middle of the flow path space, the flow of the fluid in the flow path space can be made smooth.

[0071] According to the fluid sterilization device in the present embodiment, the optical axis 144 of the light source unit 110 passes through the small-diameter portion 105 without intersecting the inner wall of the flow path tube 100. Thereby, ultraviolet light can be concentrated and irradiated to the constriction 106 of the flow path space, further improving the sterilization effect.

[0072] According to the fluid sterilization device in the present embodiment, the inlet 101 is arranged such that the inflow direction of the inflowing fluid is offset with respect to the center of the flow path tube 100. Thereby, the fluid flowing in from the inlet 101 forms a spiral flow, so that 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. As a result, the sterilization efficiency can be improved.

[0073] According to the fluid sterilization device in this embodiment, even if the flow path tube 100 is formed of a material with an ultraviolet light reflectance of 35% or less, ultraviolet light can be concentrated and irradiated on the constricted portion 106 of the flow path space, so that the sterilization effect can be improved.

[0074] According to the fluid sterilization device in this embodiment, the flow path tube 100 is formed of a material including one selected from the group consisting of stainless steel, titanium, polyvinyl chloride, polyethylene, and quartz. In this way, when a material with a high reflectance of ultraviolet light is not used for the flow path tube 100, it is difficult for the intensity of ultraviolet light to be uniform throughout the flow path space. However, by forming the constricted portion 106 in the flow path space, both the fluid and ultraviolet light can be concentrated on the constricted portion 106. Therefore, the sterilization effect can be improved even if a material with a high reflectance of ultraviolet light is not used for the flow path tube.

[0075] (Other deformation forms) In the above embodiment, the constricted portion 106 is formed in the flow path space inside the flow path tube 100 because the flow path tube 100 itself has a constricted and narrowed shape. However, the method of forming the constricted portion 106 is not limited to this. For example, the outer diameter of the flow path tube 100 may be constant, and the constricted portion 106 may be formed in the flow path space by the inner diameter changing from large diameter, small diameter, and large diameter from the first end side to the second end side.

[0076] In the above embodiment, the light source unit 110 is 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 110 may be provided only on the inlet 101 side. In this case, a reflecting member that reflects ultraviolet light is arranged on the end face on the second end side, and the sterilization efficiency can be improved by irradiating the fluid with the reflected light of ultraviolet light by this reflecting member. Also, 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 a reflecting member on the end face on the first end side. As the reflecting member, PTFE (polytetrafluoroethylene), stainless steel, titanium, etc. can be used.

[0077] In the above-described embodiment, the light source unit 110 is disposed within the flow path space, but the light source unit 110 may be disposed outside the flow path space. For example, a glass plate 132 may be disposed at an end of the flow path tube 100, and the light source unit 110 may be disposed so as not to protrude into the flow path space. Further, in the light source unit 110, the peripheral wall 136 may not be provided, and the concave portion 134 may not be formed.

Explanation of Signs

[0078] 100 Flow path tube 101 Inlet 102 Outlet 103 First large-diameter portion 104 Second large-diameter portion 105 Small-diameter portion 105b First tapered portion 105c Second tapered portion 106 Narrow portion 110 Light source unit 110A First light source unit 110B Second light source unit 144 Optical axis

Claims

1. A flow path tube formed in a cylindrical shape that forms a flow path space through which a fluid flows, having an inlet formed near the first end and an outlet formed near the second end; A first light source unit disposed near the inlet and irradiating ultraviolet light toward the second end side; A second light source unit disposed near the outlet and irradiating ultraviolet light toward the first end side, comprising: The flow path tube is formed such that an intermediate portion in the axial direction of the flow path space is constricted and narrowed, a fluid sterilization device.

2. The flow path tube is A first large diameter portion located near the first end and having the inlet formed therein; A second large diameter portion located near the second end and having the outlet formed therein; Formed between the first large diameter portion and the second large diameter portion, and having a small diameter portion smaller in diameter than the first large diameter portion and the second large diameter portion, the fluid sterilization device according to claim 1.

3. The first large diameter portion, the second large diameter portion, and the small diameter portion are arranged coaxially with each other, the fluid sterilization device according to claim 2.

4. The small diameter portion has a first tapered portion that gradually decreases in diameter from the first large diameter portion side toward the second large diameter portion side, and a second tapered portion that gradually decreases in diameter from the second large diameter portion side toward the first large diameter portion side, the fluid sterilization device according to claim 2.

5. The optical axis of the first light source unit and the optical axis of the second light source unit pass through the small diameter portion without intersecting the inner wall of the flow path tube, the fluid sterilization device according to claim 2.

6. The inlet is arranged such that the inflow direction of the inflowing fluid is offset with respect to the center of the flow path tube, the fluid sterilization device according to claim 1.

7. The flow path tube is formed of a material having an ultraviolet light reflectance of 35% or less, the fluid sterilization device according to any one of claims 1 to 6.

8. The flow path tube is formed of a material containing one selected from the group consisting of stainless steel, titanium, polyvinyl chloride, polyethylene, and quartz, the fluid sterilization device according to claim 7.

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