Fluid sterilizer

Abstract

To provide a fluid sterilizer in which an ultraviolet sensor is capable of accurately detecting illuminance of reflected light.SOLUTION: A fluid sterilizer includes a cylindrical flow path part, a light source that irradiates ultraviolet light into the flow path part, and an ultraviolet sensor disposed in the flow path part. The ultraviolet sensor is disposed so that light receiving angle characteristic value becomes less than 0.5.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] There is known a technology for sterilizing a fluid using the sterilizing power of light emitted from a light source. Patent Document 1 describes a fluid sterilization device that sterilizes a fluid flowing through a flow path by irradiating the fluid with ultraviolet light, in which a light source is disposed inside the flow path that is formed watertight. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-501122 Summary of the Invention [Problem to be solved by the invention]

[0004] The fluid sterilization device described in Patent Document 1 detects the intensity of the light source by installing a UV sensor facing the light source. This allows for early detection of UV sensor deterioration. However, fluid sterilization devices such as those described in Patent Document 1 use UV light reflected from a reflective surface in addition to UV light directly emitted from the light source for sterilization. Therefore, even if the light intensity of the light source itself has not decreased, the sterilization efficiency may decrease due to a decrease in reflected light caused by dirt or scratches on the reflective surface. Therefore, to ensure the appropriate sterilization performance of the fluid sterilization device, it is desirable to detect changes in light intensity caused by changes in the condition of the light-reflecting surface. However, currently, both direct light and reflected light are incident on the ultraviolet sensor, so it is not possible to accurately detect the illuminance of reflected light.

[0005] An object of the present invention is to provide a fluid sterilizing device in which an ultraviolet sensor can accurately detect the illuminance of reflected light. [Means for solving the problem]

[0006] (1) The fluid sterilization device is a fluid sterilization device that sterilizes a fluid using the sterilizing power of ultraviolet rays, and includes a cylindrical flow path portion, a light source that irradiates ultraviolet rays into the flow path portion, and an ultraviolet sensor provided in the flow path portion. The ultraviolet sensor has a light receiving angle characteristic of less than 0.5. Note that "the light receiving angle characteristic is less than 0.5" means that the sensitivity when ultraviolet rays are incident obliquely on the ultraviolet sensor is less than 50% of the sensitivity when incident from the front.

[0007] According to the above fluid sterilization device, direct light from the light source is less likely to affect the ultraviolet sensor, and therefore the ultraviolet sensor can detect changes in the light amount in a state where the influence of direct light is reduced. In other words, the ultraviolet sensor can accurately detect the illuminance of the reflected light.

[0008] (2) In the fluid sterilization device, the ultraviolet sensor is provided on the inner surface of the flow path portion or in the vicinity of the inner surface, and further includes a shielding portion for shielding ultraviolet rays directly incident from the ultraviolet sensor.

[0009] According to the above fluid sterilization device, direct light from the light source is less likely to enter the ultraviolet sensor. Therefore, the ultraviolet sensor can accurately detect the illuminance of the reflected light.

[0010] (3) In the fluid sterilization device, when the half-value angle of the light source is 2θ, the inner radius of the flow path in the tube of the flow path portion is r, and the distance between the light source and the ultraviolet sensor in the extending direction of the flow path portion is L, then L < r / tanθ or L ≧ 3r / tanθ.

[0011] According to the above fluid sterilization device, if L < r / tanθ, the ultraviolet sensor is arranged to avoid the region capable of receiving the direct light irradiated within the half-value angle 2θ. Further, if L ≥ 3r / tanθ, the ultraviolet sensor is arranged at a position where it can receive the reflected light that has been reflected at least once. From the above, the direct light from the light source is less likely to affect the ultraviolet sensor, and therefore the ultraviolet sensor can detect the change in the light amount in a state where the influence of the direct light is reduced. In other words, the ultraviolet sensor can accurately detect the illuminance of the reflected light.

[0012] (4) The fluid sterilization device further includes a calibration light source provided at a position facing the light source in the irradiation flow path portion for calibrating the ultraviolet sensor. According to the above fluid sterilization device, the calibration of the ultraviolet sensor becomes possible.

Effects of the Invention

[0013] According to the present invention, the ultraviolet sensor can accurately detect the illuminance of the reflected light.

Brief Description of the Drawings

[0014] [Figure 1] It is a perspective view showing the appearance of the fluid sterilization device according to the first embodiment. [Figure 2] It is an exploded perspective view showing a state where the lid member of the light source housing cassette is removed from the light source housing portion. [Figure 3] It is an exploded perspective view showing a state where the light source housing portion of the light source housing cassette is removed from the irradiation flow path portion. [Figure 4] It is an exploded perspective view showing the light source, as well as the cassette body and the lid member of the light source housing cassette. [Figure 5] It is an exploded perspective view showing a state where the light transmission portion is removed from the cassette body of the light source housing cassette. [Figure 6] It is a cross-sectional view showing the internal structure of the fluid sterilization device. [Figure 7] It is a cross-sectional view showing the internal structure of the fluid sterilization device. [Figure 8] It is a partially enlarged view of FIG. 7. [Figure 9] FIG. 2 is a cross-sectional view showing the internal structure of the fluid sterilization device. [Figure 10] FIG. 7 is a partially enlarged view of FIG. [Figure 11] FIG. 10 is a schematic cross-sectional view showing the positional relationship of ultraviolet sensors in a fluid sterilization device according to a second embodiment. [Figure 12] FIG. 2 is a block diagram showing a configuration for controlling power supply to a light source. DETAILED DESCRIPTION OF THE INVENTION

[0015] 1. First embodiment (1) Overview of the fluid sterilization device A fluid sterilizing device 1 according to a first embodiment will be described with reference to FIGS. The fluid sterilization device 1 is a device that sterilizes a fluid. The fluid sterilization device 1 sterilizes the fluid by irradiating the fluid with ultraviolet light. The fluid to be sterilized by the fluid sterilization device 1 is referred to as a treatment fluid.

[0016] An XYZ coordinate system is shown in each figure. Note that the XYZ coordinate system is not shown to indicate that the X, Y, and Z directions are strictly perpendicular to each other. The XYZ coordinate system is shown to indicate that the X, Y, and Z directions intersect at approximately right angles. Furthermore, both sides of the X direction are the X1 side and X2 side, both sides of the Y direction are the Y1 side and Y2 side, and both sides of the Z direction are the Z1 side and Z2 side.

[0017] In this embodiment, the X direction is the direction in which the treatment fluid flows through the irradiation flow path section 10 (flow path section) described below. The Y direction is the direction in which the light source accommodating cassette 32 (described below) is inserted into the inlet section 20A (described below) or the outlet section 20B (described below). Furthermore, the Y direction is the direction in which the treatment fluid flows into the fluid sterilization device 1 and the direction in which the treatment fluid flows out of the fluid sterilization device 1. In the following description, where necessary, the light source accommodating cassette 32 inserted into the inlet section 20A will be referred to as the first light source accommodating cassette 32A, and the light source accommodating cassette 32 inserted into the outlet section 20B will be referred to as the second light source accommodating cassette 32B. In this embodiment, the flow of the processing fluid in the processing fluid flow path is indicated by an outline arrow, but this is a schematic representation and is not limiting.

[0018] (2) Irradiation flow path section As shown in FIG. 1, the fluid sterilization device 1 has an irradiation flow path section 10. The irradiation flow path section 10 is a sterilization device main body that sterilizes the treatment fluid therein. The irradiation flow path section 10 is composed of a tubular member extending along the X direction. The interior of the irradiation flow path section 10 serves as a flow path for the treatment fluid. The flow path inside the irradiation flow path section 10 is referred to as irradiation flow path P3 (FIGS. 6 and 7).

[0019] Specifically, the irradiation flow path section 10 has an outer tube 12. The outer tube 12 is a member that defines the outer shape of the irradiation flow path section 10. The outer tube 12 has a round tube shape. The outer tube 12 is made of metal. The irradiation flow path section 10 has an inner tube 14. The inner tube 14 is disposed inside the outer tube 12. The inner tube 14 has a round tube shape. The inner tube 14 is made of a fluorine material, for example, a fluorine resin. An example of a fluorine resin is PTFE (Poly tetra fluoro ethylene).

[0020] The fluid sterilization device 1 has an inlet section 20A and an outlet section 20B. The inlet section 20A is a section that allows the treatment fluid to flow into the irradiation flow path section 10 from the outside. In FIG. 1, the flow path for the inflowing treatment fluid is indicated by reference numeral 71. The outlet section 20B is a section that allows the treatment fluid to flow out from the irradiation flow path section 10. In FIG. 1, the flow path for the outflowing treatment fluid is indicated by reference numeral 72. Specifically, the inlet section 20A is disposed at the X1 side end of the irradiation flow path section 10, and the outlet section 20B is disposed at the X2 side end of the irradiation flow path section 10. In other words, the inlet section 20A and the outlet section 20B are disposed opposite each other in the X direction, with the irradiation flow path section 10 sandwiched between them. The irradiation flow path section 10, the inlet section 20A, and the outlet section 20B form one flow path member.

[0021] The inlet section 20A has an internal space 21A. An inlet 22A is provided in the inlet section 20A. The inlet 22A is an opening for allowing the treatment fluid to flow into the internal space 21A of the inlet section 20A. As shown in FIG. 6, the inlet 22A has a circular cross section and opens in the Y direction. The inlet 22A is provided on the X1 side of a position (described later) where the first light source accommodating cassette 32A is inserted. When viewed in the Y direction, the edge of the inlet 22A on the X2 side coincides with the rear surface part 33B of the first light source accommodating cassette 32A. However, when viewed in the Y direction, the edge of the inlet 22A on the X2 side may be shifted toward the X1 side or the X2 side with respect to the rear surface part 33B of the first light source accommodating cassette 32A. A first flow pipe 26A is connected to the inlet 22A. The first flow pipe 26A extends in the Y direction from the inlet 22A.

[0022] The outflow section 20B has an internal space 21B. An outlet 22B is provided in the outflow section 20B. The outlet 22B is an opening for discharging the treatment fluid from the internal space 21B of the outflow section 20B. As shown in FIG. 6, the outlet 22B has a circular cross section and opens in the Y direction. The outlet 22B is provided on the X2 side of a position (described later) where the second light source accommodating cassette 32B is inserted. When viewed in the Y direction, the edge of the outlet 22B on the X1 side coincides with the rear surface part 33B of the second light source accommodating cassette 32B; however, when viewed in the Y direction, the edge of the outlet 22B on the X1 side may be shifted toward the X1 side or the X2 side with respect to the rear surface part 33B of the light source accommodating cassette 32B. A second flow pipe 26B is connected to the outlet 22B. The second flow pipe 26B extends in the Y direction from the outlet 22B.

[0023] The inlet portion 20A is provided with a main body opening 24A. As shown in FIG. 3, the main body opening 24A connects the internal space 21A of the inlet portion 20A with the external space, and is a portion that allows the first light source accommodating cassette 32A to be inserted into the internal space 21A. The main body opening 24A has a rectangular cross section and opens in the Y direction. The inlet portion 20A is provided with a main body side joint 25A. The main body side joint 25A is a flange provided around the main body opening 24A.

[0024] The outlet portion 20B is provided with a main body opening 24B. As shown in FIG. 3, the main body opening 24B connects the internal space 21B of the outlet portion 20B with the external space, and is a portion that allows the second light source accommodating cassette 32B to be inserted into the internal space 21B. The main body opening 24B has a rectangular cross section and opens in the Y direction. The outlet portion 20B is provided with a main body side joint 25B. The main body side joint 25B is a flange provided around the main body opening 24B.

[0025] (3) Light source The fluid sterilization device 1 has a pair of light sources 31 that emit ultraviolet light within the irradiation flow path section 10. The light sources 31 are components that emit ultraviolet light. The light sources 31 are, for example, UV (Ultraviolet)-LEDs (Light Emitting Diodes). In this embodiment, the UV-LEDs that are the light sources 31 are mounted on a wiring board 41, as shown in FIG. 4. The light sources 31 and the wiring board 41 on which the light sources 31 are mounted are combined to form a surface light source module 42 (which may further include other components). The surface light source module 42 is removably mounted in the light source accommodating section 33 of the light source accommodating cassette 32 and is positioned by, for example, a leaf spring 43 .

[0026] (4) Light source housing cassette (4-1) Structure of the light source housing cassette The fluid sterilization device 1 has a pair of light source accommodating cassettes 32 (32A, 32B). The light source accommodating cassettes 32 are members that accommodate light sources 31 and can be attached to the irradiation flow path section 10. Each light source accommodating cassette 32 is removably installed in the inlet section 20A and the outlet section 20B. This structure makes it easy to replace the light source 31.

[0027] As shown in FIGS. 3 to 5, the light source accommodating cassette 32 has a light source accommodating section 33 that accommodates the light source 31, and a lid member 34 for closing the light source accommodating section 33.

[0028] The light source accommodating unit 33 is a flat housing having a front surface 33A, a rear surface 33B, a tip surface 33C, and a pair of side surfaces 33D. The front surface 33A and the rear surface 33B are flat surfaces facing each other and having a predetermined area. Hereinafter, the direction extending along the plane of the front surface 33A and the rear surface 33B is referred to as the cassette horizontal direction, and the direction perpendicular to the cassette horizontal direction is referred to as the cassette perpendicular direction. The tip surface 33C is a curved surface connecting the tip of the front surface 33A to the tip of the rear surface 33B. The pair of side surfaces 33D are flat surfaces connecting both sides of the front surface 33A and the rear surface 33B. The light source accommodating cassette 32 has a cassette opening 35 on the side opposite the tip surface 33C. The cassette opening 35 is a structure that allows the light source 31 to be inserted into and removed from the light source accommodating unit 33 along the cassette horizontal direction.

[0029] The cover member 34 has an attachment portion 46 that is detachably joined to a cassette-side joint portion 40 (described later). The attachment portion 46 is a flange, and is joined to the cassette-side joint portion 40 by a plurality of bolts 73.

[0030] The surface light source module 42 is in contact with or close to the inside of the rear surface portion 33B of the light source housing portion 33. Therefore, the rear surface portion 33B serves as a light source cooling surface that is cooled by the processing fluid. With this structure, heat from the light source 31 can be efficiently released into the processing fluid (described later).

[0031] As described above, the light source 31 is disposed inside the light source accommodating section 33. Therefore, when the light source accommodating cassette 32 is disposed in the inflow section 20A or the outflow section 20B as shown in FIGS. 1 and 2, the light source 31 does not come into contact with the processing fluid.

[0032] The light source accommodating cassette 32 has a light transmitting section 36 that transmits ultraviolet light emitted by the light source 31. The light transmitting section 36 has quartz glass 37.

[0033] The front surface 33A of the light source accommodating cassette 32 has a window opening 38 in which a light-transmitting portion 36 is provided. The light-transmitting portion 36 has an attachment member 39 that removably attaches the quartz glass 37 to the window opening 38. Therefore, as shown in FIG. 5 , the quartz glass 37 of the light-transmitting portion 36 can be easily removed from the window opening 38, making it easy to clean and replace the quartz glass 37. The quartz glass 37 is generally flush with the front surface 33A. The light-transmitting portion 36 may be made of any material that has a high transmittance of ultraviolet light, such as sapphire.

[0034] Specifically, the quartz glass 37 is in the shape of a disk having a predetermined thickness, as shown in Fig. 5. The mounting member 39 is an annular member, and mainly has a ring portion 81 and a plurality of claw portions 82. The ring portion 81 is fitted onto the outer periphery of the quartz glass 37. The plurality of claw portions 82 extend from the ring portion 81 and support the outer surface of the quartz glass 37.

[0035] As shown in FIG. 8 , the ring portion 81 has a ring portion main body 84 and a protruding portion 85. The protruding portion 85 extends inward from the ring portion main body 84 and has a threaded portion 86 on its outer circumferential surface. The threaded portion 86 is threadedly engaged with a threaded portion 87 provided on the window opening 38. A first seal member 89 is disposed between the outer periphery of the inner surface of the quartz glass 37 and the support portion 88 of the window opening 38. A ring-shaped second seal member 90 is disposed between the outer periphery of the quartz glass 37 and the inner circumferential surface of the ring portion 81. With the above configuration, the interior of the light source housing cassette 32 is sealed off from the processing fluid. Furthermore, when attaching the quartz glass 37 to the window opening 38, the attachment member 39 is rotated with the quartz glass 37 fitted into it, thereby threading the threaded portion 86 into the threaded portion 87 of the window opening 38. When removing the quartz glass 37 from the window opening 38, the mounting member 39 is rotated to release the threaded portion 86 from the threaded portion 87. With the above structure, the quartz glass 37 can be inserted into the window opening 38 from the vertical direction of the cassette and easily fixed using the mounting member 39.

[0036] The light source accommodating portion 33 of the first light source accommodating cassette 32A is removably inserted into the internal space 21A through the main body opening 24A, as shown in Fig. 3. The cassette insertion direction (Y direction) is the direction along the inflow direction of the treatment fluid.

[0037] The light source accommodating portion 33 of the second light source accommodating cassette 32B is removably inserted into the internal space 21B through the main body opening 24B, as shown in Fig. 3. The cassette insertion direction (Y direction) is the direction along the outflow direction of the treatment fluid.

[0038] The light source accommodating cassette 32 has a cassette-side joint 40. The cassette-side joint 40 is a member that seals the inlet 20A or outlet 20B when attached to the inlet 20A or outlet 20B. Specifically, when the light source accommodating cassette 32 is inserted into the inlet 20A, the cassette-side joint 40 joins with the main body-side joint 25A to seal the inlet 20A. When the light source accommodating cassette 32 is inserted into the outlet 20B, the cassette-side joint 40 joins with the main body-side joint 25B to seal the outlet 20B. The cassette-side joint 40 is a flange, and is joined to the main body-side joints 25A, 25B with a plurality of bolts 74.

[0039] (4-2) Effect of the light source storage cassette 2, the surface light source module 42 can be replaced by removing the cover member 34 of the light source accommodating cassette 32 from the light source accommodating section 33. During this operation, there is no need to drain water from the irradiation flow path section 10. Furthermore, contamination does not occur in the irradiation flow path section 10 due to exposure to the atmosphere.

[0040] As shown in Figure 3, the quartz glass 37 can be cleaned and replaced by removing the light source accommodating cassette 32 from the irradiation flow path section 10. When carrying out the above work, there is no need to disassemble the irradiation flow path section 10. As a result, the structure, work, and maintenance space required for disassembling the irradiation flow path section 10 are no longer required.

[0041] (5) The light source cassette is attached to the irradiation flow path. (5-1) Overview When the light source accommodating cassette 32 is attached to the irradiation flow path section 10, each of the pair of light sources 31 is disposed so as to irradiate ultraviolet light toward the irradiation flow path P3. Specifically, the light sources 31 are disposed in the internal spaces 21A and 21B so as to emit light toward the irradiation flow path section 10. The light from the light sources 31 is irradiated onto the irradiation flow path section 10 via the quartz glass 37. Therefore, the treatment fluid flowing through the irradiation flow path section 10 is sterilized by ultraviolet irradiation from the X1 side and ultraviolet irradiation from the X2 side in the X direction. Specifically, the treatment fluid is sterilized by direct light from the light sources 31 and light reflected by the inner circumferential surface of the inner tube 14.

[0042] (5-2) The first light source housing cassette is inserted into the inlet. A front surface 33A of the light source accommodating section 33 of the first light source accommodating cassette 32A faces the irradiation flow path P3. That is, a back surface 33B of the first light source accommodating cassette 32A in the inflow section 20A faces the upstream side (X1 side) in the flow direction (X direction). In the internal space 21A of the inflow section 20A, the X1 side of the first light source accommodating cassette 32A is the inflow flow path P1.

[0043] The light source accommodating section 33 is disposed approximately in the center of the internal space 21A in the Z direction. The tip surface portion 33C of the light source accommodating section 33 abuts or is close to the inner surface of the internal space 21A. As shown in FIG. 6, the side surface portion 33D of the first light source accommodating cassette 32A forms a pair of communication flow paths P2 between itself and the side wall surface portion 51 of the inlet portion 20A. The pair of communication flow paths P2 extend in the direction along the flow direction (X direction). The pair of communication flow paths P2 face each other in the Z direction. Here, "the pair of communication flow paths P2 face each other in the Z direction" means that the lengths and positions of the two communication flow paths P2 in the X direction are the same or correspond to each other.

[0044] As described above, the first light source accommodating cassette 32A, in which the light source accommodating portion 33 accommodating the light source 31 and the light transmitting portion 36 are integrally and detachably formed, forms a pair of communication flow paths P2.

[0045] (5-3) The second light source storage cassette is inserted into the outlet. The front surface 33A of the light source accommodating section 33 of the second light source accommodating cassette 32B faces the irradiation flow path P3 side. In other words, the back surface 33B of the second light source accommodating cassette 32B in the outflow section 20B faces the downstream side (X2 side) in the flow direction. In the internal space 21B of the outflow section 20B, the X2 side of the second light source accommodating cassette 32B is the outflow flow path P5. The outflow flow path P5 has a length in the X direction sufficient to allow the treatment fluid to flow around after hitting an end surface portion 55 (described below) and then flow toward the second light source accommodating cassette 32B.

[0046] The light source accommodating section 33 is disposed approximately in the center of the internal space 21B in the Z direction. As shown in FIG. 9, the tip surface portion 33C of the light source accommodating section 33 abuts or is close to the inner surface of the internal space 21B. As shown in FIGS. 6, 9, and 10, the side surface portion 33D of the second light source accommodating cassette 32B forms a pair of communication flow paths P4 between itself and the side wall surface portion 52 of the outflow section 20B. The pair of communication flow paths P4 extend in the direction along the flow direction (X direction). The pair of communication flow paths P4 face each other in the Z direction. Here, "the pair of communication flow paths P4 face each other in the Z direction" means that the lengths and positions of the two communication flow paths P4 in the X direction are the same or correspond to each other.

[0047] As shown in Fig. 10, the inner wall surface of the outflow section 20B has a terminal surface portion 55. The terminal surface portion 55 is a flat surface formed on the inner wall on the downstream side of the second light source accommodating cassette 32B, and faces the back surface portion 33B of the second light source accommodating cassette 32B in the X direction. The terminal surface portion 55 is parallel to the back surface portion 33B. The space between the back surface portion 33B and the terminal surface portion 55 forms the outflow flow path P5. The provision of the terminal surface portion 55 makes it easier for the processing fluid to flow toward the back surface portion 33B, thereby improving the effectiveness of cooling the light source 31.

[0048] As shown in the XZ cross section of FIG. 10 , the inner wall surface of the outflow section 20B has an inclined surface portion 56. The inclined surface portion 56 is inclined so that the flow path inner diameter decreases toward the X2 side (downstream side) of the second light source housing cassette 32B. Specifically, the inclined surface portion 56 is a pair of inclined surface portions formed on both sides of the outflow section 20B in the Z direction. The inclined surface portion 56 extends between the side wall surface portion 52 and the terminal surface portion 55. The inclined surface portion is curved so that the middle portion is concave in the Y direction. The inclined surface portion 56 facilitates the flow of the processing fluid toward the rear surface portion 33B, and as a result, the processing fluid does not stagnate around the rear surface portion 33B (the flow velocity of the processing fluid around the rear surface portion 33B is sufficiently high). In other words, circulation of the processing fluid is promoted in the outflow flow path P5, thereby improving the cooling effect of the light source 31.

[0049] (6) Effects According to the above configuration, the light source 31 can be replaced while the interior of the fluid sterilization device 1 is sealed. Specifically, as shown in Fig. 2, when the cassette-side joint 40 of the light source storage cassette 32 is joined to the main body-side joint 25A, 25B of the inlet portion 20A or the outlet portion 20B, the inlet portion 20A or the outlet portion 20B is sealed. In this state, the light source 31 can be removed from or inserted into the main body openings 24A, 24B. In other words, the light source 31 can be replaced while the inlet portion 20A or the outlet portion 20B is sealed.

[0050] The above configuration facilitates the cleaning and replacement of the light-transmitting portion 36. Specifically, as shown in Fig. 5, by removing the light source accommodating cassette 32 from the inlet portion 20A or the outlet portion 20B, the light-transmitting portion 36 can also be removed. This facilitates the cleaning and replacement of the light-transmitting portion 36.

[0051] Unlike the present embodiment, if the light source is directly inserted into the irradiation flow path section, the quartz glass will be installed in the irradiation flow path section, and therefore a separate outlet will need to be provided for maintenance such as cleaning or replacing the quartz glass.

[0052] Furthermore, unlike the present embodiment, if the light source and quartz glass are constructed as separate structures from the irradiation flow path section, it will be necessary to drain the water from the irradiation flow path section even when replacing the light source, which is relatively frequent, and this will require time for the work.In addition, when used for purified water applications where sanitation is required, the exposure to the atmosphere will result in contamination by common bacteria and the like.

[0053] (7) Flow behavior of the processing fluid The flow of the fluid to be treated in the fluid sterilization device 1 will be explained briefly with reference to FIG. First, the processing fluid flows from the outside through the inlet 22A into the inlet flow path P1 of the inlet section 20A along the Y direction. At this time, since the inlet 22A faces the Y direction, the processing fluid flows parallel to the entire back surface 33B of the first light source accommodating cassette 32A, that is, the processing fluid hits the back surface 33B evenly. Therefore, the light source 31 is cooled almost uniformly throughout.

[0054] Next, the processing fluid flows through the pair of communication flow paths P2 from the X1 side to the X2 side in the X direction, and flows into the irradiation flow path P3 of the irradiation flow path section 10. In detail, after flowing through the communication flow path P2 in the X direction, the processing fluid hits the wall surface 61 of the inlet section 20A facing the X1 side, changes direction radially inward (Z direction), and then flows into the irradiation flow path P3. Therefore, the processing fluid flows in a rectified state, enveloping the first light source accommodating cassette 32A, and the light source 31 can be effectively cooled. In the above, the front surface 33A, the side surface 33D, and the back surface 33B of the first light source accommodating cassette 32A serve as rectifying surfaces.

[0055] In contrast to this, unlike the present embodiment, when the fluid flowing into the inlet portion is split into two flow paths at a front and rear position in the inflow direction, the flow rate of the fluid flowing through the front flow path is less than the flow rate of the fluid flowing through the rear flow path. In other words, an imbalance in the flow rates occurs between the two flow paths, making it difficult for a flow to envelop the light source housing cassette. As a result, it is difficult to improve the cooling effect of the light source.

[0056] Next, the treatment fluid flows through the irradiation flow path P3 of the irradiation flow path section 10 in the X direction from the X1 side to the X2 side. The treatment fluid is sterilized by being irradiated with ultraviolet light in the irradiation flow path P3. At this time, the ultraviolet light includes direct light from the light source 31 and light reflected from the inner tube 14.

[0057] Next, the treatment fluid flows from the irradiation flow path P3 into the pair of communication flow paths P4. Specifically, after hitting the front surface 33A of the second light source accommodating cassette 32B, the treatment fluid turns radially outward (in the Z direction) and then flows into the pair of communication flow paths P4. The treatment fluid flows through the pair of communication flow paths P4 from the X1 side to the X2 side in the X direction and flows into the outflow flow path P5 of the outflow portion 20B. Therefore, the treatment fluid flows in a rectified state, enveloping the second light source accommodating cassette 32B, thereby effectively cooling the light source 31. In the above, the front surface 33A, side surface 33D, and rear surface 33B of the second light source accommodating cassette 32B serve as rectifying surfaces.

[0058] In the outlet flow path P5, the processing fluid flows toward the X2 side while being rectified along the inclined surface portion 56 of the outlet portion 20B, and further reaches the terminal surface portion 55. Thereafter, the processing fluid changes direction and flows toward the X1 side, i.e., toward the back surface portion 33B. As a result, the light source 31 can be efficiently cooled.

[0059] As described above, the processing fluid changes its flow direction (specifically, the flow on the X2 side becomes the flow on the X1 side) before being discharged from the outlet 22B downstream of the second light source housing cassette 32B in the outflow section 20B, making it easier to flow toward the rear surface section 33B. In other words, the processing fluid mainly hits the rear surface section 33B before flowing out from the outlet 22B. As a result of the above, the light source 31 can be efficiently cooled. In other words, wear and tear on the light source 31 can be reduced.

[0060] In the outlet flow path P5, the processing fluid finally flows out through the outlet 22B to the outside.

[0061] 2. Second embodiment The second embodiment will be described with reference to Figures 11 and 12. The basic configuration and basic operation of the second embodiment are the same as those of the first embodiment. Therefore, the following description will focus on the differences.

[0062] (1) UV sensor (1-1) Function of UV sensor As shown in Figure 11, the fluid sterilization device 1 includes an ultraviolet sensor 91. The ultraviolet sensor 91 is a sensor for detecting the illuminance of the periphery of the inner surface of the irradiation flow path section 10 by the light source 31. Note that Figure 11 shows only the first light source accommodating cassette 32A of the light source accommodating cassettes 32 in which the light source 31 and the quartz glass 37 are provided.

[0063] 12, the fluid sterilization device 1 has a power supply unit 27 that supplies power to the light source 31, a control unit 28, and a lid opening / closing sensor 29. The ultraviolet sensor 91 can send detection results to the control unit 28. The lid opening / closing sensor 29 is a sensor that detects when the lid member 34 of the first light source accommodating cassette 32A has been removed from the cassette opening 35. For example, the lid opening / closing sensor 29 is a microswitch that turns on and off depending on whether the lid member 34 is opened or closed relative to the cassette opening 35.

[0064] The control unit 28 controls the operation of the power supply unit 27 based on the ultraviolet irradiance detected by the ultraviolet sensor 91. When the fluid sterilization device 1 is operating, that is, when the treatment fluid is being supplied to the irradiation flow path P3, the control unit 28 controls the power supply unit 27 to increase or decrease the amount of ultraviolet irradiation from the light source 31 so that the measured ultraviolet irradiance is constant, thereby allowing the treatment fluid in the irradiation flow path P3 to be irradiated with ultraviolet light of the desired intensity.

[0065] The control unit 28 can determine whether the light source 31 has failed or deteriorated based on the ultraviolet illuminance detected by the ultraviolet sensor 91.

[0066] When the control unit 28 determines that the cover member 34 has been removed from the cassette opening 35 based on a detection signal from the cover open / close sensor 29, it cuts off the power supply from the power supply unit 27 to the light source 31. With the above configuration, even when the light source 31 is exposed to the outside, as shown in Figure 2, for example, the light source 31 does not irradiate ultraviolet light. This increases the safety of the worker.

[0067] (1-2) UV sensor position As shown in FIG. 11 , the ultraviolet sensor 91 is provided on or near the inner surface of the inner tube 14 of the irradiation flow path unit 10. By providing the ultraviolet sensor 91 at this location, it can receive reflected light from the inner tube 14 (shown by the symbol RL in FIG. 11 as an example). As a result, it is possible to not only monitor the decrease in the light intensity of the light source 31 itself, but also detect overall changes in the light intensity, including the effects of changes in the condition of the inner tube 14 due to contamination (e.g., deposition, etc.) or scratches. As a result, the control unit 28 can more reliably detect whether the light intensity is sufficient for the required sterilization performance. In other words, the control unit 28 can quickly detect a decrease in sterilization efficiency. As a result, by appropriately replacing the light source 31 or cleaning the irradiation flow path unit 10, it is possible to ensure appropriate sterilization performance in the fluid sterilization device 1.

[0068] The ultraviolet sensor 91 is disposed at the center of the irradiation flow path section 10 in the X direction. That is, the ultraviolet sensor 91 is located at the same distance L from the pair of light sources 31. The central axis 93 of the light receiving surface 92 of the ultraviolet sensor 91 is perpendicular to the optical axis 94 of the light source 31 .

[0069] More specifically, the ultraviolet sensor 91 has a light-receiving angle characteristic of less than 0.5. Note that "a light-receiving angle characteristic of less than 0.5" means that the sensitivity when ultraviolet light is incident on the ultraviolet sensor 91 at an angle is less than 50% of the sensitivity when the light is incident from the front. With this configuration, direct light from the light source 31 is less likely to affect the ultraviolet sensor 91, and therefore the ultraviolet sensor 91 can detect changes in the amount of light in a state where the influence of direct light (shown by the symbol DL as an example in FIG. 11) is reduced. In other words, the ultraviolet sensor 91 can accurately detect the illuminance of reflected light.

[0070] More specifically, the light-receiving surface 92 of the ultraviolet sensor 91 is located further back than the inner circumferential surface of the inner tube 14 to prevent direct light from the light source 31 from entering. Furthermore, the fluid sterilization device 1 includes a shielding portion 95 for blocking ultraviolet light directly incident on the ultraviolet sensor 91. Specifically, the shielding portion 95 is a cylindrical member that holds the ultraviolet sensor 91 inside and is fixed to the outer tube 12. The tip surface of the shielding portion 95 extends to the inner circumferential surface of the inner tube 14. This configuration reduces the likelihood of direct light DL from the light source 31 being received by the ultraviolet sensor 91. In other words, no or very little direct light is incident on the ultraviolet sensor 91. Therefore, the ultraviolet sensor 91 can accurately detect the illuminance of the reflected light. As a result, the control unit 28 can determine whether the inner circumferential surface of the inner tube 14 is dirty or damaged. Even when only a small amount of direct light enters the ultraviolet sensor 91, the illuminance of the reflected light can be detected with some degree of accuracy if the extent of the influence of the direct light is known.

[0071] The light receiving surface of the ultraviolet sensor 91 may be flush with the inner circumferential surface of the inner tube 14, or may protrude from the inner circumferential surface of the inner tube 14. Furthermore, the tip surface of the shielding portion 95 may be located deeper than the inner circumferential surface of the inner tube 14, or may protrude from the inner circumferential surface of the inner tube 14. The shielding function may be achieved by another structure instead of the shielding portion 95.

[0072] More specifically, when the half-value angle of the light source is 2θ, the inner radius of the irradiation channel P3 in the inner tube 14 of the irradiation channel portion 10 is r, and the distance between the light source 31 and the ultraviolet sensor 91 in the extension direction (X direction) of the irradiation channel portion 10 is L, then L < r / tanθ or L ≧ 3r / tanθ. According to this configuration, if L < r / tanθ, the ultraviolet sensor 91 is arranged avoiding the region capable of receiving the direct light irradiated within the half-value angle 2θ. Also, if L ≧ 3r / tanθ, the ultraviolet sensor 91 is arranged at a position where it can receive the reflected light that has been reflected at least once. From the above, the direct light from the light source 31 hardly affects the ultraviolet sensor 91, and therefore the ultraviolet sensor 91 can detect the change in the light quantity in a state where the influence of the direct light is reduced. In other words, the ultraviolet sensor 91 can accurately detect the illuminance of the reflected light.

[0073] As shown in FIG. 11, the fluid sterilization device 1 further includes a calibration light source 96. The calibration light source 96 is a light source for calibrating the ultraviolet sensor 91. The calibration light source 96 is provided at a position facing the ultraviolet sensor 91. The calibration light source 96 irradiates the ultraviolet sensor 91 with ultraviolet rays within a certain light quantity range. The calibration light source 96 lights up only during calibration.

[0074] 3. Other Embodiments and Variations As described above, the embodiments of the present invention have been explained, but the present invention is not limited to the above-described embodiments, and various changes, modifications, and combinations are possible. The number of light sources may be one instead of two.

[0075] There may be no inclined surface portion in the inflow portion and the outflow portion. The structure of the inflow portion and the structure of the outflow portion may be different from each other.

[0076] 4. Contribution to the Sustainable Development Goals (SDGs) Led by the United Nations This disclosure includes matters contributing to the achievement of Goal 6, "Ensure availability and sustainable management of water and sanitation for all," and Goal 9, "Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation," of the SDGs (Sustainable Development Goals). [Explanation of symbols]

[0077] 1:Fluid sterilizer 10: Irradiation flow path section 12:Outer tube 14: Inner tube 31:Light source 32: Light source housing cassette 32A: First light source housing cassette 37: Quartz glass 38: Window opening 91: UV sensor 92: Light receiving surface 93: Central axis 94: Optical axis 95: Shielding part 96: Calibration light source DL: Direct light RL: Reflected light

Claims

1. A fluid sterilization device that sterilizes a fluid using the sterilizing power of ultraviolet light, A cylindrical flow path portion; a light source that irradiates ultraviolet light into the flow path portion; an ultraviolet sensor provided in the flow path portion, A fluid sterilization device, wherein the ultraviolet sensor is provided so that the light-receiving angle characteristic is less than 0.

5.

2. the ultraviolet sensor is provided on an inner surface of the flow path portion or in the vicinity of the inner surface, The fluid sterilization device according to claim 1 , further comprising a shielding portion for blocking ultraviolet light directly incident from the ultraviolet sensor.

3. When the half-value angle of the light source is 2θ, the inner radius of the flow path in the pipe of the flow path portion is r, and the distance between the light source and the ultraviolet sensor in the extension direction of the flow path portion is L, 3. The fluid sterilizing device of claim 1 or 2, wherein L<r / tan θ or L≧3r / tan θ.

4. The fluid sterilization device according to claim 1 or 2, further comprising a calibration light source for calibrating the ultraviolet sensor, the calibration light source being provided in the irradiation flow path section at a position facing the light source.

Images