Fluid sterilization device

Abstract

This fluid sterilization device comprises: a flow path part; an inflow part; an outflow part; a light-source storage cassette including a light-source storage part, a light-transmission part, an optical cassette opening part, and a cassette-side joining part; and a light source. At least the inflow part or the outflow part has: a body opening part for inserting the light-source storage cassette into the inflow part or the outflow part; and a body-side joining part for sealing the inflow part or the outflow part by joining with the cassette-side joining part in a state in which the light source storage cassette is inserted into the inflow part or the outflow part.

Description

fluid sterilizer

[0001] This application claims priority from Japanese Patent Application No. 2024-76453, filed May 9, 2024, the contents of which are incorporated herein by reference.

[0002] There is known a technology for sterilizing a fluid using the sterilizing power of light emitted from a light source. Patent Document 1 discloses 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 a watertight flow path.

[0003] Patent No. 6458779

[0004] However, when the fluid sterilization device is configured so that the light source can be removably inserted into the main body of the fluid sterilization device, the quartz glass through which the light from the light source passes is installed inside the main body of the fluid sterilization device. In this configuration, it is necessary to provide the fluid sterilization device with an access port for removing the quartz glass from the inside of the fluid sterilization device when cleaning or replacing the quartz glass.

[0005] If the light source and quartz glass are integrated and separated from the main body of the fluid sterilizer, the main body of the fluid sterilizer must be drained even when replacing the light source, which is relatively frequent, which takes time.Furthermore, when the fluid sterilizer is used for purified water that requires sanitary conditions, the exposure to the atmosphere can lead to contamination by common bacteria and other bacteria.

[0006] The present invention aims to provide a fluid sterilizer that allows replacement of a light source while the interior of the fluid sterilizer is sealed, and that also facilitates cleaning and replacement of the light-transmitting part.

[0007] (1) A fluid sterilization device for sterilizing a fluid using ultraviolet light includes a cylindrical flow path, an inlet, an outlet, a light source emitting ultraviolet light within the flow path, and a light source housing cassette. The light source housing cassette is removably installed in at least one of the inlet or outlet, and includes a light source housing for housing the light source, a light-transmitting portion for transmitting ultraviolet light emitted by the light source, a cassette opening for inserting the light source into the light source housing, and a cassette-side joint for sealing the inlet or outlet when attached to the inlet or outlet. At least one of the inlet or outlet has a main body opening for inserting the light source housing cassette into the inlet or outlet, and a main body-side joint that joins with the cassette-side joint to seal the inlet or outlet when the light source housing cassette is inserted into the inlet or outlet.

[0008] The above-described fluid sterilization device allows replacement of the light source while the interior of the fluid sterilization device is sealed, and furthermore, it is possible to provide a fluid sterilization device that facilitates cleaning and replacement of the light-transmitting portion. Specifically, when the cassette-side joint of the light source-accommodating cassette is joined to the main-body-side joint of the inlet or outlet portion, the inlet or outlet portion is sealed. In this state, the light source can be removed or inserted through the cassette opening. In other words, the light source can be replaced while the inlet or outlet portion is sealed. Furthermore, by removing the light source-accommodating cassette from the inlet or outlet portion, the light-transmitting portion can also be removed. Therefore, cleaning and replacement of the light-transmitting portion is facilitated.

[0009] (2) In the fluid sterilization device, the light source-accommodating cassette further includes a window opening in which the light-transmitting portion is provided, and the light-transmitting portion includes quartz glass and a mounting portion that removably mounts the quartz glass to the window opening. According to the fluid sterilization device, the quartz glass is removably mounted to the window opening by the mounting portion, so that the quartz glass can be easily removed from the window opening. This makes it easy to clean and replace the quartz glass.

[0010] (3) In the fluid sterilization device, when the direction in which the light source accommodating cassette is inserted into the inlet or outlet is defined as an insertion direction and the direction in which the fluid flows through the flow path is defined as a flow direction, the insertion direction is a direction intersecting the flow direction. The light source accommodating cassette further includes flow path forming portions formed at both ends opposite to the direction intersecting the insertion direction, which form a fluid flow path between the light source accommodating cassette and the inner wall of the inlet or outlet when the light source accommodating cassette is inserted into the inlet or outlet. According to the above-described fluid sterilization device, the fluid flows by dividing into two flow paths formed by the light source accommodating cassette. In other words, the fluid flows in a manner that envelops the light source accommodating cassette, thereby effectively cooling the light source accommodating cassette. Furthermore, the light source can be effectively cooled.

[0011] (4) The fluid sterilization device further includes at least one of an inlet, which is disposed upstream of the inlet portion where the light source-accommodating cassette is inserted, and which opens in a direction intersecting the flow direction, through which the fluid flows into the inlet portion, or an outlet, which is disposed downstream of the outlet portion where the light source-accommodating cassette is inserted, and which opens in a direction intersecting the flow direction, through which the fluid flows out of the outlet portion. When the direction in which the fluid flows from the inlet to the inlet portion is defined as the inlet direction and the direction in which the fluid flows out of the outlet portion is defined as the outlet direction, at least one of the inlet direction and the outlet direction is a direction along the insertion direction. According to the above-described fluid sterilization device, since the inlet direction is aligned with the insertion direction, the fluid that flows into the inlet portion changes direction in a direction intersecting the inlet direction and then flows on both sides of the light source-accommodating cassette. This makes it easier for the fluid to flow in a manner that envelops the light source-accommodating cassette, thereby effectively cooling the light source.

[0012] (5) The fluid sterilization device further includes a cover member removably attached to the cassette opening, a power supply that supplies power to the light source, and a power control unit that cuts off the power supply to the light source when the cover member is removed from the cassette opening. With the above fluid sterilization device, ultraviolet light is not emitted when the light source is exposed to the outside, thereby increasing safety.

[0013] According to the present invention, it is possible to provide a fluid sterilization device in which the light source can be replaced while the interior of the fluid sterilization device is sealed, and further, the light-transmitting part can be easily cleaned and replaced.

[0014] FIG. 8 is a perspective view showing the appearance of the fluid sterilization device according to the first embodiment. FIG. 9 is an exploded perspective view showing a state in which a lid member of a light source accommodating cassette has been removed from a light source accommodating section. FIG. 10 is an exploded perspective view showing a state in which a light source accommodating section of the light source accommodating cassette has been removed from an irradiation flow path section. FIG. 11 is an exploded perspective view showing a light source, a cassette body and a lid member of the light source accommodating cassette. FIG. 12 is an exploded perspective view showing a state in which a light transmitting section has been removed from a cassette body of the light source accommodating cassette. FIG. 13 is a cross-sectional view showing the internal structure of the fluid sterilization device. FIG. 14 is a cross-sectional view showing the internal structure of the fluid sterilization device. FIG. 15 is a partial enlarged view of FIG. 7. FIG. 16 is a cross-sectional view showing the internal structure of the fluid sterilization device. FIG. 17 is a partial enlarged view of FIG. 6. FIG. 18 is a schematic cross-sectional view showing the positional relationship of ultraviolet sensors in a fluid sterilization device according to a second embodiment. FIG. 19 is a block diagram showing the power supply control configuration of a light source.

[0015] 1. First Embodiment (1) Overview of the Fluid Sterilization Device A fluid sterilization device 1 according to a first embodiment will be described using Figures 1 to 9. 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 direction, Y direction, and Z direction are strictly perpendicular to each other. The XYZ coordinate system is shown to indicate that the X direction, Y direction, and Z direction intersect with each other so as to be approximately perpendicular to each other. Furthermore, both sides of the X direction are defined as the X1 side and X2 side, both sides of the Y direction are defined as the Y1 side and Y2 side, and both sides of the Z direction are defined as 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, as 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 treatment fluid in the treatment 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 the 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 within 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 through which a treatment fluid flows from the outside into the irradiation flow path section 10. In FIG. 1 , the flow path of the inflowing treatment fluid is indicated by reference numeral 71. The outlet section 20B is a section through which the treatment fluid flows out of the irradiation flow path section 10. In FIG. 1 , the flow path of 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. That is, 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 therebetween. The irradiation flow path section 10, the inlet section 20A, and the outlet section 20B constitute one flow path member.

[0021] The inlet section 20A has an internal space 21A. The inlet section 20A is provided with an inlet 22A. 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 below) where the first light source housing cassette 32A is inserted. When viewed in the Y direction, the X2-side edge of the inlet 22A coincides with the rear surface 33B of the first light source housing cassette 32A. However, when viewed in the Y direction, the X2-side edge of the inlet 22A may be offset toward the X1 side or the X2 side relative to the rear surface 33B of the first light source housing cassette 32A. A first circulation pipe 26A is connected to the inlet 22A. The first circulation pipe 26A extends in the Y direction from the inlet 22A.

[0022] The outflow section 20B has an internal space 21B. The outflow section 20B is provided with an outlet 22B. 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 below) where the second light source accommodating cassette 32B is inserted. When viewed in the Y direction, the X1-side edge of the outlet 22B coincides with the rear surface 33B of the second light source accommodating cassette 32B. However, when viewed in the Y direction, the X1-side edge of the outlet 22B may be offset toward the X1 side or the X2 side relative to the rear surface 33B of the light source accommodating cassette 32B. A second circulation pipe 26B is connected to the outflow section 22B. The second circulation 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 allows the first light source housing 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 allows the second light source housing 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 . A component that combines the light sources 31 and the wiring board 41 on which the light sources 31 are mounted (which may further include other components) is called a surface light source module 42. The surface light source module 42 is removably mounted within the light source housing section 33 of the light source housing cassette 32 and is positioned by, for example, a leaf spring 43.

[0026] (4) Light Source Storage Cassette (4-1) Structure of the Light Source Storage Cassette The fluid sterilization device 1 has a pair of light source storage cassettes 32 (32A, 32B). The light source storage cassettes 32 are members that store light sources 31 and can be attached to the irradiation flow path section 10. Each light source storage 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 cover 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 33B of the light source housing 33. Therefore, the rear surface 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 Figures 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 portion 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, facilitating cleaning and replacement of the quartz glass 37. The quartz glass 37 is generally flush with the front portion 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 includes 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. An annular 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 the attachment member 39 to thread 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] 3, 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. The cassette insertion direction (Y direction) is the direction along the inflow direction of the treatment fluid.

[0037] 3, 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. 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 Housing Cassette As shown in Figure 2, the surface light source module 42 can be replaced by removing the cover member 34 of the light source housing cassette 32 from the light source housing portion 33. During this operation, there is no need to drain the water from the irradiation flow path portion 10. Furthermore, contamination does not occur in the irradiation flow path portion 10 due to exposure to the atmosphere.

[0040] 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. This cleaning and replacement work does not require disassembly of 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) State in which the light source accommodating cassette is attached to the irradiation flow path section (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 arranged to irradiate ultraviolet light toward the irradiation flow path P3. Specifically, the light sources 31 are arranged in the internal spaces 21A and 21B to emit light toward the irradiation flow path section 10. 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) State when the first light source accommodating cassette is inserted into the inflow section The front surface 33A of the light source accommodating section 33 of the first light source accommodating cassette 32A faces the irradiation flow path P3. In other words, the 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 communicating flow paths P2 between itself and the side wall surface portion 51 of the inlet portion 20A. The pair of communicating flow paths P2 extend in the direction along the flow direction (X direction). The pair of communicating flow paths P2 face each other in the Z direction. Here, "the pair of communicating flow paths P2 face each other in the Z direction" means that the lengths and positions of the two communicating 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 section 33 accommodating the light source 31 and the light transmitting section 36 are integrally and detachably formed, forms a pair of communication flow paths P2.

[0045] (5-3) State in which the second light source accommodating cassette is inserted into the outlet portion: The front surface 33A of the light source accommodating portion 33 of the second light source accommodating cassette 32B faces the irradiation flow path P3. In other words, the back surface 33B of the second light source accommodating cassette 32B in the outlet portion 20B faces the downstream side (X2 side) in the flow direction. In the internal space 21B of the outlet portion 20B, the X2 side of the second light source accommodating cassette 32B is the outlet flow path P5. The outlet flow path P5 has a length in the X direction sufficient to allow the treatment fluid to flow around after hitting the terminal 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 at 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 outlet portion 20B. The pair of communication flow paths P4 extend in 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 55. The terminal surface 55 is a flat surface formed on the inner wall downstream of the second light source accommodating cassette 32B, and faces the rear surface 33B of the second light source accommodating cassette 32B in the X direction. The terminal surface 55 is parallel to the rear surface 33B. The space between the rear surface 33B and the terminal surface 55 forms an outflow flow path P5. The provision of the terminal surface 55 makes it easier for the processing fluid to flow toward the rear surface 33B, thereby improving the effectiveness of cooling the light source 31.

[0048] As shown in the X-Z cross section of FIG. 10 , the inner wall surface of the outlet portion 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 surfaces formed on both sides of the outlet portion 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 56 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, thereby preventing the processing fluid from stagnating around the rear surface portion 33B (the flow rate of the processing fluid around the rear surface portion 33B is sufficiently high). In other words, the circulation of the processing fluid in the outlet flow path P5 is promoted, thereby improving the cooling effect of the light source 31.

[0049] (6) Effect 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 cleaning and replacement of the light-transmitting portion 36. Specifically, as shown in Fig. 5, the light-source-accommodating cassette 32 can be removed from the inlet portion 20A or the outlet portion 20B, thereby also removing the light-transmitting portion 36. This facilitates 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 of Processing Fluid The flow of processing fluid in the fluid sterilization device 1 will be explained briefly using Figure 6. First, the processing fluid flows from the outside through the inlet 22A into the inlet flow path P1 of the inlet 20A along the Y direction. At this time, since the inlet 22A faces the Y direction, the processing fluid flows parallel to the entire rear surface 33B of the first light source housing cassette 32A, i.e., it hits the rear surface 33B evenly. Therefore, the light source 31 is cooled almost uniformly throughout.

[0054] Next, the treatment 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. More specifically, after flowing through the communication flow path P2 in the X direction, the treatment 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 treatment fluid flows in a rectified state, enveloping the first light source accommodating cassette 32A, thereby effectively cooling the light source 31. In the above, the front surface 33A, side surface 33D, and rear 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 the front and rear positions 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 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 section 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 then 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 exiting 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 A 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) Ultraviolet Light (1-1) Function of the Ultraviolet Light Sensor As shown in Fig. 11, the fluid sterilization device 1 includes an ultraviolet light sensor 91. The ultraviolet light sensor 91 is a sensor for detecting the illuminance of the light source 31 around the inner surface of the irradiation flow path section 10. Note that Fig. 11 illustrates only the first light source accommodating cassette 32A among 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 storage 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 illuminance 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 radiation from the light source 31 so that the measured ultraviolet illuminance remains constant, thereby allowing the treatment fluid in the irradiation flow path P3 to be irradiated with ultraviolet radiation of a 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) Position of the UV Sensor As shown in FIG. 11 , the UV sensor 91 is located on or near the inner surface of the inner tube 14 of the irradiation flow path unit 10. By locating the UV sensor 91 in this position, it can receive reflected light from the inner tube 14 (shown as an example by the symbol RL in FIG. 11 ). 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, the appropriate sterilization performance of the fluid sterilization device 1 can be ensured.

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

[0069] More specifically, the UV 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 of the UV sensor 91 when UV light is incident at an angle is less than 50% of the sensitivity when UV light is incident from the front. This configuration makes it difficult for direct light from the light source 31 to affect the UV sensor 91, so the UV sensor 91 can detect changes in the amount of light while reducing the influence of direct light (shown by the symbol DL in FIG. 11 , for example). In other words, the UV 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 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 is incident on the ultraviolet sensor 91, the illuminance of the reflected light can be detected with some degree of accuracy if the degree of 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, if the half-value angle of the light source is 2θ, the inner radius of the irradiation flow path P3 in the inner tube 14 of the irradiation flow path section 10 is r, and the distance between the light source 31 and the UV sensor 91 in the extension direction (X direction) of the irradiation flow path section 10 is L, then L < r / tan θ or L ≥ 3r / tan θ holds. According to this configuration, if L < r / tan θ, the UV sensor 91 is positioned to avoid an area where it can receive direct light irradiated within the half-value angle 2θ. Furthermore, if L ≥ 3r / tan θ holds, the UV sensor 91 is positioned in a position where it can receive reflected light that has been reflected at least once. As a result, direct light from the light source 31 is less likely to affect the UV sensor 91, and therefore the UV sensor 91 can detect changes in the amount of light with reduced influence from direct light. In other words, the UV sensor 91 can accurately detect the illuminance of reflected light.

[0073] As shown in Figure 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 in a position facing the ultraviolet sensor 91. The calibration light source 96 irradiates ultraviolet light within a certain light intensity range toward the ultraviolet sensor 91. The calibration light source 96 is turned on only during calibration.

[0074] While the present invention has been described above with reference to the preferred embodiments, it is not limited to the preferred embodiments and various modifications, variations, and combinations are possible. The number of light sources may be one instead of two.

[0075] The inlet and outlet portions may not have sloped surfaces. The inlet and outlet portions may have different structures.

[0076] 4. Contribution to the United Nations-led Sustainable Development Goals (SDGs) This disclosure includes matters that contribute to achieving SDG (Sustainable Development Goals) Goal 6, "Clean water and sanitation," and Goal 9, "Industry, innovation and infrastructure."

[0077] DESCRIPTION OF SYMBOLS 1: Fluid sterilization device 10: Irradiation flow path section 20A: Inflow section 20B: Outflow section 21A: Internal space 22A: Inflow port 22B: Outflow port 24A: Main body opening 24B: Main body opening 25A: Main body side joint section 25B: Main body side joint section 31: Light source 32: Light source accommodating cassette 32A: First light source accommodating cassette 32B: Second light source accommodating cassette 33: Light source accommodating section 33B: Back section 33D: Side section 34: Lid member 35: Cassette opening 36: Light transmitting section 37: Quartz glass 39: Mounting member 40: Cassette side joint section 51: Side wall surface section 52: Side wall surface section

Claims

1. A fluid sterilization device for sterilizing a fluid with ultraviolet light, comprising: a cylindrical flow path portion; an inlet portion arranged at one end of the flow path portion; an outlet portion arranged at the other end of the flow path portion; a light source that emits ultraviolet light into the flow path portion; and a light source accommodating cassette that is removably installed in at least one of the inlet portion or the outlet portion and that includes a light source accommodating portion that accommodates the light source, a light transmission portion that transmits ultraviolet light emitted by the light source, a cassette opening for inserting the light source into the light source accommodating portion, and a cassette-side joint for sealing the inlet portion or the outlet portion when attached to the inlet portion or the outlet portion, wherein the light source is accommodated in the light source accommodating portion from the cassette opening and emits ultraviolet light into the flow path portion via the light transmission portion, and at least one of the inlet portion or the outlet portion has: a main body opening for inserting the light source accommodating cassette into the inlet portion or the outlet portion; and a main body-side joint that joins with the cassette-side joint when the light source accommodating cassette is inserted into the inlet portion or the outlet portion, to seal the inlet portion or the outlet portion.

2. The fluid sterilization device according to claim 1, wherein the light source accommodating cassette further comprises a window opening in which the light transmitting portion is provided, and the light transmitting portion comprises quartz glass and an attachment portion for removably attaching the quartz glass to the window opening.

3. A fluid sterilization device as described in claim 1 or 2, wherein, when the direction in which the light source accommodating cassette is inserted into the inlet or outlet portion is defined as an insertion direction and the direction in which the fluid flows through the flow path portion is defined as a flow direction, the insertion direction is a direction intersecting the flow direction, and the light source accommodating cassette further has flow path forming portions formed on both end portions opposite to each other in a direction intersecting the insertion direction, which form a flow path for the fluid between the light source accommodating cassette and the inner wall of the inlet or outlet portion when the light source accommodating cassette is inserted into the inlet or outlet portion.

4. A fluid sterilization device as described in claim 3, further comprising at least one of: an inlet provided upstream of the position at the inlet where the light source accommodating cassette is inserted, opening in a direction intersecting the flow direction, and through which the fluid flows into the inlet; or an outlet provided downstream of the position at the outlet where the light source accommodating cassette is inserted, opening in a direction intersecting the flow direction, and through which the fluid flows out of the outlet; wherein when the direction in which the fluid flows from the inlet to the inlet part is defined as the inlet direction and the direction in which the fluid flows out of the outlet part is defined as the outlet direction, at least one of the inlet direction and the outlet direction is a direction along the insertion direction.

5. A fluid sterilization device as described in claim 1 or 2, further comprising: a cover member that is removably attached to the cassette opening; a power source that supplies power to the light source; and a power control unit that cuts off the power supply from the power source to the light source when the cover member is removed from the cassette opening.

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