Liquid treatment device

Abstract

To provide a liquid treatment device which can detect reduction in strength of ultraviolet light for irradiating liquid, the reduction being caused by a light emitting element.SOLUTION: A liquid treatment device according to an embodiment includes: a casing which has a recess part having an opening on its one end; a light emitting element which is provided on the inside of the recess part and which emits ultraviolet light; a first detection part which is provided on the inside of the recess part and which detects the ultraviolet light emitted from the light emitting element; and a window which closes the opening of the recess part and which transmits the ultraviolet light emitted from the light emitting element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to a liquid treatment device. [Background technology]

[0002] There are liquid treatment devices that irradiate liquids such as water with ultraviolet light to sterilize the liquid or remove organic matter contained in the liquid. For example, a liquid treatment device has been proposed that has a housing, a light-emitting element (e.g., a light-emitting diode) that is provided inside the housing and emits ultraviolet light, and a window that is provided at an opening of the housing and seals the internal space of the housing in which the light-emitting element is provided.

[0003] Here, the intensity of the ultraviolet light irradiated onto the liquid may decrease. For example, since the window comes into contact with the liquid, the surface of the window may become dirty. When the window surface becomes dirty, the intensity of the ultraviolet light irradiated onto the liquid through the window decreases. Furthermore, when the ultraviolet light transmittance through the liquid decreases, the intensity of the ultraviolet light irradiated onto the liquid located away from the liquid treatment device decreases. Furthermore, when the function of the light-emitting element deteriorates or breaks down, the intensity of the ultraviolet light irradiated onto the liquid decreases. Regardless of the cause, if the intensity of the ultraviolet light irradiated onto the liquid decreases, the sterilization effect of the liquid may decrease.

[0004] For this reason, a technology has been proposed in which a detection unit for detecting the intensity of ultraviolet light is provided outside the housing. By providing a detection unit outside the housing, it is possible to detect a decrease in the intensity of ultraviolet light irradiated onto the liquid. However, since there are multiple factors that can cause a decrease in the intensity of ultraviolet light irradiated onto the liquid, even if a detection unit is provided outside the housing and the intensity of ultraviolet light is detected, it is not possible to determine whether the decrease in the intensity of ultraviolet light is caused by the light-emitting element.

[0005] Therefore, there has been a demand for the development of a liquid treatment device that can detect a decrease in the intensity of ultraviolet light irradiated onto the liquid, which is caused by the light emitting element. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2017-051290 [Patent Document 2] Japanese Patent Application Publication No. 2018-069158 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a liquid treatment device that can detect a decrease in the intensity of ultraviolet light irradiated onto a liquid, which decrease is caused by a light emitting element. [Means for solving the problem]

[0008] The liquid treatment device of the embodiment comprises a housing having a recess that opens at one end; a light-emitting element that is provided inside the recess and emits ultraviolet light; a first detection unit that is provided inside the recess and detects the ultraviolet light emitted from the light-emitting element; and a window that covers the opening of the recess and transmits the ultraviolet light emitted from the light-emitting element. [Effects of the Invention]

[0009] According to an embodiment of the present invention, it is possible to provide a liquid treatment device that can detect a decrease in the intensity of ultraviolet light irradiated onto a liquid, which decrease is caused by a light emitting element. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic perspective view illustrating a liquid treatment apparatus according to an embodiment of the present invention. [Figure 2] 2 is a schematic cross-sectional view of the liquid treatment device in FIG. 1 taken along line AA. [Figure 3] FIG. 10 is a schematic cross-sectional view illustrating a liquid treatment apparatus according to another embodiment. [Figure 4] FIG. 10 is a schematic cross-sectional view illustrating a liquid treatment apparatus according to another embodiment. [Figure 5]1A and 1B are schematic cross-sectional views illustrating a state in which a liquid treatment device is used. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be illustrated with reference to the drawings. In the drawings, like components are designated by like reference numerals and detailed descriptions thereof will be omitted where appropriate.

[0012] FIG. 1 is a schematic perspective view illustrating a liquid treatment device 1 according to the present embodiment. FIG. 2 is a schematic cross-sectional view of the liquid treatment device 1 in FIG. 1 taken along the line AA. The liquid treatment device 1 can be, for example, immersed in the liquid to be treated. As shown in FIGS. 1 and 2, the liquid treatment device 1 includes, for example, a housing 2, a light source 3, a window 4, a seal 5, a detection unit 6 (which corresponds to an example of a first detection unit), and a connector 7.

[0013] The housing 2 is block-shaped and has a recess 2a that opens at one end. The planar shape of the housing 2 can be any shape, such as a circle, an ellipse, or a polygon. However, if the shape is composed of curves such as a circle or an ellipse, it is possible to prevent turbulence in the flow of the liquid when the housing 2 is immersed in the liquid to be processed. Furthermore, even if the housing 2 collides with the inner wall of the flow path, it is possible to prevent the inner wall of the flow path from being damaged, or the housing 2 from being chipped or cracked. In this case, if the planar shape of the housing 2 is made approximately circular, as shown in FIG. 1, it becomes easier to manufacture the housing 2.

[0014] The planar dimensions and thickness of the housing 2 can be changed as appropriate depending on the size of the light source 3, the use of the liquid treatment device 1, and the like.

[0015] As shown in FIGS. 1 and 2, a light source 3 is provided inside the recess 2a. The light source 3 emits ultraviolet rays 3a1, which are incident on the inner wall of the recess 2a. For this reason, the housing 2 preferably contains a material that is highly resistant to the ultraviolet rays 3a1. For example, if the housing 2 contains a general resin, the ultraviolet rays 3a1 emitted from the light source 3 may damage the housing 2 or shorten its lifespan.

[0016] Furthermore, the housing 2 is immersed in the liquid to be treated. Therefore, it is preferable that the housing 2 contains a material that is highly corrosion-resistant to the liquid to be treated. For example, if the housing 2 contains a general metal, the liquid to be treated may corrode the housing 2 or shorten its lifespan.

[0017] For example, the housing 2 preferably contains an inorganic material. For example, the housing 2 can be formed from ceramics such as steatite or aluminum oxide. This makes it possible to obtain a housing 2 that is highly resistant to ultraviolet light 3a1 and highly resistant to corrosion by the liquid used for processing. In this case, if white ceramics such as steatite or aluminum oxide are used, the ultraviolet light 3a1 that is incident on the inner wall of the recess 2a is more likely to be reflected. This makes it possible to improve the utilization efficiency of the ultraviolet light 3a1 emitted from the light source 3.

[0018] The light source 3 is provided inside the recess 2a of the housing 2. For example, the light source 3 is provided in a space defined by the recess 2a and the window 4. For example, the light source 3 can be detachably provided on the bottom surface of the recess 2a, or can be bonded to the bottom surface of the recess 2a.

[0019] The light source 3 includes, for example, a light emitting element 3a and a substrate 3b. The light-emitting element 3a is provided on the surface of the substrate 3b opposite to the bottom side of the recess 2a. The light-emitting element 3a emits ultraviolet light 3a1. The ultraviolet light 3a1 emitted from the light-emitting element 3a is irradiated mainly to the outside of the liquid treatment device 1 through the window 4. At least one light-emitting element 3a can be provided. The light source 3 illustrated in Figures 1 and 2 is provided with multiple light-emitting elements 3a. When multiple light-emitting elements 3a are provided, the multiple light-emitting elements 3a can be connected in series. The number and arrangement of the light-emitting elements 3a can be changed as appropriate depending on the size and planar shape of the housing 2, the required processing capacity of the liquid treatment device 1, etc.

[0020] The light emitting element 3a is not particularly limited as long as it is an element that emits ultraviolet light 3a1, and may be, for example, a light emitting diode or a laser diode. The form of the light-emitting element 3a is not particularly limited. The light-emitting element 3a may be, for example, a surface-mounted light-emitting element, a bullet-shaped light-emitting element having lead wires, or a chip-shaped light-emitting element. The chip-shaped light-emitting element 3a may be any of an upper electrode type, a top and bottom electrode type, and a flip-chip type.

[0021] The peak wavelength of the ultraviolet light 3a1 emitted from the light-emitting element 3a can be changed as appropriate depending on the intended use of the liquid treatment device 1. For example, if the peak wavelength is 260 nm to 280 nm, it is possible to effectively sterilize bacteria, inactivate viruses, decompose organic matter, and so on.

[0022] The substrate 3b is plate-shaped and is provided on the bottom surface of the recess 2a. For example, the substrate 3b can be attached to the bottom surface of the recess 2a using a fastening member such as a screw. In this way, the substrate 3b (light source 3) can be detachably provided on the bottom surface of the recess 2a, thereby improving maintainability.

[0023] Furthermore, a layer of thermally conductive grease (heat dissipation grease) can be provided between the substrate 3b and the bottom surface of the recess 2a. If a layer of thermally conductive grease is provided, it is possible to prevent a gap from being formed between the substrate 3b and the bottom surface of the recess 2a. This makes it easier for heat generated in the light-emitting element 3a to be transferred to the housing 2, thereby preventing the temperature of the light-emitting element 3a from exceeding the maximum junction temperature.

[0024] Alternatively, for example, the substrate 3b can be bonded to the bottom surface of the recess 2a using an adhesive or double-sided tape. In this case, the adhesive is preferably one with high thermal conductivity. The adhesive can be, for example, an adhesive mixed with a filler using an inorganic material such as aluminum oxide.

[0025] If the substrate 3b is bonded to the bottom surface of the recess 2a, it is possible to prevent a gap from occurring between the substrate 3b and the bottom surface of the recess 2a. Therefore, it is possible to prevent the temperature of the light-emitting element 3a from exceeding the maximum junction temperature. Furthermore, since the configuration of the liquid treatment device 1 is simplified, it is possible to reduce manufacturing costs.

[0026] A wiring pattern can be provided on the surface of the substrate 3b opposite to the bottom side of the recess 2a, and the light emitting element 3a can be electrically connected to the wiring pattern.

[0027] The material of the substrate 3b may be resistant to ultraviolet light 3a1. The material of the substrate 3b may be, for example, a ceramic such as aluminum oxide. Alternatively, the substrate 3b may be, for example, a metal core substrate in which the surface of a metal plate is covered with an inorganic material.

[0028] In this case, since ceramics and metal core substrates have high thermal conductivity, if these are used to form the substrate 3b, the heat generated in the light-emitting element 3a will be easily transferred to the housing 2. Therefore, the temperature of the light-emitting element 3a can be prevented from exceeding the maximum junction temperature.

[0029] The window 4 is plate-shaped and covers the opening of the recess 2a of the housing 2. The window 4 faces the light-emitting element 3a. The window 4 is made of a material that can transmit ultraviolet light 3a1 emitted from the light-emitting element 3a and is resistant to the ultraviolet light 3a1 and the liquid used for processing. The window 4 is made of, for example, quartz or a resin (such as a fluororesin or silicone resin) that transmits ultraviolet light 3a1.

[0030] An anti-reflection film can be provided on the surface of the window 4 facing the light-emitting element 3a. If an anti-reflection film is provided, it is possible to prevent the ultraviolet light 3a1 emitted from the light-emitting element 3a from being reflected by the window 4 and making it difficult for the ultraviolet light 3a1 to be irradiated onto the liquid to be treated. In other words, it is possible to improve the utilization efficiency of the ultraviolet light 3a1 emitted from the light-emitting element 3a.

[0031] An anti-fouling film may be provided on the surface of the window 4 opposite the light-emitting element 3a side. For example, the liquid treatment device 1 may be used to sterilize bacteria, inactivate viruses, and decompose organic matter contained in seawater, groundwater, and the like. Seawater, groundwater, and the like contain foreign matter such as sand, microbial corpses, and inorganic salts, which may adhere to the surface of the window 4 opposite the light-emitting element 3a side. If foreign matter adheres to the surface of the window 4, it becomes difficult for the ultraviolet light 3a1 emitted from the light-emitting element 3a to pass through the window 4, which may reduce the sterilization effect of the liquid. The provision of an anti-fouling film can prevent foreign matter from adhering to the window 4, thereby maintaining the intensity of the ultraviolet light 3a1 irradiated onto the liquid to be treated for a long period of time and reducing the frequency of maintenance.

[0032] The seal 5 is provided between the window 4 and the housing 2. The seal 5 can be provided, for example, near the opening of the recess 2a. The liquid treatment device 1 is immersed in the liquid to be treated. Therefore, the seal 5 seals the space defined by the recess 2a and the window 4 so that it is liquid-tight. The seal 5 can be formed, for example, by hardening a softened resin. The resin can be, for example, a silicone resin. In this way, the space defined by the recess 2a and the window 4 can be sealed and the window 4 can be joined to the housing 2.

[0033] The seal 5 can also be a sealing member such as an O-ring. In this way, the window 4 can be provided detachably in the housing 2, facilitating maintenance of the light source 3. When the seal 5 is a sealing member, a metal fitting or the like for holding the window 4 can be provided at the end of the housing 2 where the recess 2a opens.

[0034] Here, the intensity of the ultraviolet light 3a1 irradiated onto the liquid may decrease. For example, as mentioned above, if foreign matter adheres to the surface of window 4, ultraviolet light 3a1 emitted from light-emitting element 3a is less likely to pass through window 4, resulting in a decrease in the intensity of ultraviolet light 3a1 irradiated onto the liquid. Furthermore, if the transmittance of ultraviolet light 3a1 through the liquid decreases, the intensity of ultraviolet light 3a1 irradiated onto a liquid located away from liquid treatment device 1 decreases. Furthermore, if the function of light-emitting element 3a deteriorates or breaks down, the intensity of ultraviolet light 3a1 irradiated onto the liquid also decreases. Regardless of the cause, a decrease in the intensity of ultraviolet light 3a1 irradiated onto the liquid may reduce the sterilization effect of the liquid.

[0035] In this case, contamination of the window 4 and a decrease in the transmittance of ultraviolet light 3a1 through the liquid can be predicted to a certain extent. However, the deterioration in performance of the light-emitting element 3a varies from one light-emitting element 3a to another. Furthermore, failure of the light-emitting element 3a is sudden. Furthermore, the deterioration in performance or failure of the light-emitting element 3a has a significant impact on the sterilization effect of the liquid. Therefore, it is important to detect a decrease in the intensity of ultraviolet light 3a1 irradiated onto the liquid that is caused by the light-emitting element 3a.

[0036] Therefore, the liquid treatment device 1 according to this embodiment is provided with a detection unit 6 that detects ultraviolet light 3a1 emitted from the light emitting element 3a. The detection unit 6 can be provided inside the recess 2a of the housing 2. The detection unit 6 detects ultraviolet light 3a1 emitted from the light-emitting element 3a inside the recess 2a of the housing 2. The light-emitting element 3a has, for example, a photodiode that detects the ultraviolet light 3a1, and a conversion unit that converts a current that depends on the intensity of the ultraviolet light 3a1 from the photodiode into an analog voltage and amplifies the current.

[0037] It is also possible to provide a photodiode inside the recess 2a of the housing 2 and provide a conversion unit in the controller 100, which will be described later. In this case, the photodiode provided inside the recess 2a of the housing 2 can be electrically connected to the conversion unit provided in the controller 100, etc., via the connector 7 and the wiring cable 101.

[0038] 1 and 2 is a photodiode that detects ultraviolet light 3a1. In this way, the detection unit 6 can be made smaller, and the liquid treatment device 1 can also be made smaller.

[0039] Furthermore, although the detection unit 6 has been described as having a photodiode that detects ultraviolet light 3a1, the detection unit 6 may also have, for example, a phosphor unit that converts ultraviolet light 3a1 into visible light and a photodiode that detects visible light. The phosphor unit may be provided, for example, on the light-receiving surface of the photodiode. In general, photodiodes that detect visible light are smaller and less expensive than photodiodes that detect ultraviolet light 3a1. Therefore, using a detection unit 6 that includes a photodiode that detects visible light allows for the liquid treatment device 1 to be made smaller and more affordable.

[0040] As shown in Fig. 2, ultraviolet light 3a1 emitted from light-emitting element 3a is irradiated onto the liquid outside liquid treatment device 1 through window 4. At this time, part of ultraviolet light 3a1 emitted from light-emitting element 3a is reflected by window 4 and the inner wall of recess 2a. Note that in Fig. 2, to avoid complexity, only part of the reflected ultraviolet light 3a1 is depicted.

[0041] In this case, if the detector 6 is provided inside the recess 2a of the housing 2, the ultraviolet light 3a1 reflected by the window 4 and the inner wall of the recess 2a can be made to enter the detector 6. Therefore, if the detection unit 6 is provided inside the recess 2a of the housing 2, it can detect a decrease in the intensity of the ultraviolet light 3a1 emitted from the light-emitting element 3a, and ultimately a decrease in the intensity of the ultraviolet light 3a1 irradiated onto the liquid caused by the light-emitting element 3a.

[0042] As shown in FIG. 2, the detection unit 6 can be provided, for example, on the bottom side of the recess 2a. As described above, a substrate 3b is provided on the bottom side of the recess 2a. Therefore, when the detection unit 6 is provided on the bottom side of the recess 2a, a hole for inserting the detection unit 6 can be provided in the substrate 3b. The position of the detection unit 6 in the direction parallel to the bottom surface of the recess 2a is not particularly limited. However, as shown in FIG. 2, if the detection unit 6 is located at the center of the bottom surface of the recess 2a, it becomes easy to provide multiple light-emitting elements 3a at positions symmetrical with respect to the central axis of the liquid treatment device 1 (housing 2). Therefore, it is possible to prevent bias in the irradiation area of the liquid treatment device 1.

[0043] 2, the distance between the surface of substrate 3b and the top (light receiving portion) of detector 6 is preferably equal to or smaller than the distance between the surface of substrate 3b and the top (emitting surface) of light emitting element 3a. This prevents ultraviolet light 3a1 emitted from light emitting element 3a from being blocked by detector 6. This improves the efficiency of extracting ultraviolet light 3a1 from liquid treatment device 1.

[0044] Furthermore, the detection unit 6 can also be provided on the surface of the substrate 3b opposite to the bottom surface of the recess 2a. If the detection unit 6 is provided on the substrate 3b, it becomes easy to electrically connect the detection unit 6 to the connector 7. In this case, there are no particular limitations on the position of the detection unit 6 on the surface of the substrate 3b. However, if the detection unit 6 is located in the center of the surface of the substrate 3b, it becomes easy to provide multiple light-emitting elements 3a in positions symmetrical with respect to the central axis of the liquid treatment device 1 (housing 2). Therefore, it is possible to prevent bias in the irradiation area of the liquid treatment device 1.

[0045] The connector 7 can be provided on the outer surface of the housing 2. For example, the connector 7 can be provided on the outer surface of the housing 2 or on the end of the housing 2 opposite to the side where the recess 2a opens. In the case of the liquid treatment device 1 illustrated in FIG. 1, the connector 7 is provided on the outer surface of the housing 2.

[0046] When the liquid treatment device 1 is immersed in the liquid to be treated, the connector 7 may be a so-called waterproof connector. The connector 7 may be, for example, a connector that complies with IP68 specified in JIS C 0920.

[0047] The connector 7 includes, for example, a plug 7a and a socket 7b. The plug 7a can be provided, for example, on the outer surface of the housing 2. The plug 7a can be provided liquid-tightly in a hole that penetrates between the outer surface of the housing 2 and the inner wall of the recess 2a. A terminal provided inside the plug 7a is electrically connected to the light-emitting element 3a provided on the substrate 3b and the detection unit 6 via wiring or the like.

[0048] The socket 7b is detachably connected to the end of the plug 7a opposite to the housing 2 side. When the socket 7b and the plug 7a are connected, the space between the socket 7b and the plug 7a is sealed liquid-tight, and a terminal provided inside the socket 7b and a terminal provided inside the plug 7a are electrically connected. The terminal provided inside the socket 7b is electrically connected to a controller 100 (described later) and the like via a wiring cable 101.

[0049] The provision of connector 7 makes it easy to connect and disconnect wiring cable 101 to and from housing 2, in which light source 3, window 4, seal 5, and detection unit 6 are provided, thereby improving the maintainability of liquid treatment device 1.

[0050] FIG. 3 is a schematic cross-sectional view illustrating a liquid treatment device 1a according to another embodiment. The liquid treatment device 1a may be configured by further providing a reflecting section 8 to the liquid treatment device 1 described above.

[0051] As shown in FIG. 3, the reflecting portion 8 can be provided inside the recess 2a. For example, the reflecting portion 8 can be provided on the light-emitting element 3a side of the window 4. The reflecting portion 8 can be provided in a position facing the detecting portion 6. The reflecting portion 8 can be made of a material that has a high reflectivity for the ultraviolet light 3a1 emitted from the light-emitting element 3a. The reflecting portion 8 can be made of a metal such as aluminum or stainless steel. The reflecting portion 8 can also be a laminate having, for example, a resin film and a metal film. The reflecting portion 8 can be, for example, adhered to the surface of the window 4 or deposited by vapor deposition on the surface of the window 4. Furthermore, although the example in FIG. 3 shows a case where the reflecting section 8 is provided on the surface of the window 4, the reflecting section 8 may be provided between the window 4 and the detecting section 6.

[0052] The detection unit 6 detects ultraviolet light 3a1 emitted from the light-emitting element 3a and reflected by the reflector 8. If the reflector 8 is provided, it is possible to increase the amount of ultraviolet light 3a1 incident on the detection unit 6. As a result, it is possible to increase the detection sensitivity of the detection unit 6. As described above, an anti-reflection film may be provided on the surface of the window 4 facing the light-emitting element 3a. In such a case, if the reflector 8 is provided, the anti-reflection film can increase the amount of ultraviolet light 3a1 that passes through the window 4, and the reflector 8 can increase the amount of ultraviolet light 3a1 that enters the detection unit 6.

[0053] FIG. 4 is a schematic cross-sectional view illustrating a liquid treatment device 1b according to another embodiment. As shown in FIG. 4, the detection unit 6 can also be provided on the side wall of the recess 2a. For example, the detection unit 6 can be embedded in the side wall of the recess 2a. As described above, part of the ultraviolet rays 3a1 emitted from the light-emitting element 3a also travels toward the side wall of the recess 2a. Therefore, even if the detection unit 6 is provided on the side wall of the recess 2a, the ultraviolet rays 3a1 emitted from the light-emitting element 3a can be incident on the detection unit 6.

[0054] In this case, it is preferable that the detector 6 does not protrude from the side wall of the recess 2a. This can prevent the ultraviolet light 3a1 emitted from the light-emitting element 3a from being blocked by the detector 6. This can improve the efficiency of extracting the ultraviolet light 3a1 from the liquid treatment device 1.

[0055] Furthermore, it is preferable that the distance between the bottom surface of the recess 2a and the end of the detecting unit 6 on the bottom side of the recess 2a is equal to or greater than the distance between the bottom surface of the recess 2a and the top (emission surface) of the light-emitting element 3a. In this way, ultraviolet light 3a1 emitted from the light-emitting element 3a can be more easily incident on the detecting unit 6, thereby increasing the detection sensitivity of the detecting unit 6.

[0056] 4, if the detection unit 6 is provided on the side wall of the recess 2a, the number of light-emitting elements 3a can be increased. Also, even if the number of light-emitting elements 3a is the same, the liquid treatment device 1b can be made smaller.

[0057] Next, the state of use of the liquid treatment device 1 will be described. Although the use state of the liquid treatment device 1 will be described as an example, the use state of the liquid treatment device 1a or the liquid treatment device 1b is similar.

[0058] FIG. 5 is a schematic cross-sectional view illustrating the liquid treatment device 1 in use. As shown in FIG. 5, the liquid treatment device 1 can be provided inside a flow path pipe 201, for example. The flow path pipe 201 is made of, for example, a material that is resistant to the liquid 200. The flow path pipe 201 can be made of, for example, a metal that is resistant to corrosion by water or seawater. Examples of metals that are resistant to corrosion by water or seawater include stainless steel (e.g., SUS304, SUS316, etc.) and titanium. The flow path pipe 201 can also be made of, for example, a resin (e.g., polypropylene, high-density polyethylene, etc.).

[0059] That is, the liquid treatment device 1 can be immersed in the flowing liquid 200 . The liquid treatment device 1 can also be immersed in the stored liquid 200. For example, the liquid treatment device 1 can also be provided inside a tank. If the liquid treatment device 1 is immersed in the liquid 200, the liquid 200 can be efficiently irradiated with ultraviolet light 3a1. In addition, since the light source 3 can be cooled by the liquid 200, the temperature of the light-emitting element 3a can be prevented from exceeding the maximum junction temperature.

[0060] 5, the controller 100 is electrically connected to the light emitting element 3a and the detection unit 6 via a wiring cable 101. The controller 100 is provided outside the flow path pipe 201, and may include, for example, a power supply, a lighting circuit, and a calculation circuit for the intensity of ultraviolet light 3a1.

[0061] The controller 100 turns on the light-emitting element 3a to irradiate the liquid 200 with ultraviolet light 3a1. When the liquid 200 is irradiated with ultraviolet light 3a1, bacteria contained in the liquid 200 are killed, viruses are inactivated, and organic matter is decomposed. For example, when the water contained in the liquid 200 is irradiated with ultraviolet light 3a1, hydroxyl radicals with strong oxidizing power are generated. Hydroxyl radicals are effective in killing bacteria and inactivating viruses. In addition, the hydroxyl radicals decompose the total organic carbon (TOC) contained in the liquid 200 into carbon dioxide via organic acids.

[0062] In addition, based on the output signal from the detection unit 6, the controller 100 can detect a decrease in the intensity of the ultraviolet light 3a1 emitted from the light-emitting element 3a, and ultimately a decrease in the intensity of the ultraviolet light 3a1 irradiated onto the liquid 200 caused by the light-emitting element 3a. Furthermore, the controller 100 can also determine, based on the output signal from the detector 6, whether the light-emitting element 3a is malfunctioning or malfunctioning.

[0063] Furthermore, a detection unit 16 (corresponding to an example of a second detection unit) may be provided outside the housing 2. The detection unit 16 is electrically connected to the controller 100 and detects ultraviolet light 3a1 emitted from the light-emitting element 3a and transmitted through the liquid 200. For example, as shown in FIG. 5, a window 16a may be provided in the wall surface of the flow path pipe 201, and the detection unit 16 may be provided outside the flow path pipe 201 at a position facing the window 16a. The detection unit 16 is electrically connected to the controller 100, for example, via a wiring cable 101. The detection unit 16 detects the intensity of the ultraviolet light 3a1 irradiated onto the liquid 200 through the window 16a. The detection unit 16 may be similar to the detection unit 6, for example.

[0064] If the detection unit 16 is provided, it is possible to detect a decrease in the intensity of ultraviolet light 3a1 due to multiple factors such as dirt on the window 4, fluctuations in the transmittance of ultraviolet light 3a1 in the liquid 200, and a decrease in the function or failure of the light-emitting element 3a.

[0065] In this case, if the controller 100 determines that there is no abnormality in the light-emitting element 3a based on the output signal from the detection unit 6, it can determine that the decrease in the intensity of the ultraviolet light 3a1 is due to factors such as dirt on the window 4 or fluctuations in the transmittance of the ultraviolet light 3a1 in the liquid 200. Furthermore, if the controller 100 determines that there is an abnormality in the light-emitting element 3a based on the output signal from the detection unit 6, it can determine that the decrease in intensity of the ultraviolet light 3a1 is at least caused by the light-emitting element 3a. That is, the controller 100 can determine the cause of the decrease in intensity of the ultraviolet light 3a1 based on the output signal from the detector 6 and the output signal from the detector 16. Therefore, if the detectors 6 and 16 are provided, it becomes easier to perform appropriate maintenance.

[0066] Although several embodiments of the present invention have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other. [Explanation of symbols]

[0067] 1 liquid treatment device, 1a liquid treatment device, 1b liquid treatment device, 2 housing, 2a recess, 3 light source, 3a light emitting element, 3a1 ultraviolet light, 3b substrate, 4 window, 5 seal, 6 detection unit, 8 reflection unit, 16 detection unit, 200 liquid, 201 liquid transfer tube

Claims

1. a housing having a recess that opens at one end; a light-emitting element provided inside the recess and emitting ultraviolet light; a first detector provided inside the recess and configured to detect the ultraviolet light emitted from the light-emitting element; a window that closes the opening of the recess and transmits the ultraviolet light emitted from the light-emitting element; A liquid treatment device comprising:

2. Further, a reflecting portion is provided inside the recess, The liquid treatment device according to claim 1 , wherein the first detection unit detects the ultraviolet light emitted from the light emitting element and reflected by the reflecting unit.

3. a controller electrically connected to the first detection unit; 3. The liquid treatment device according to claim 1, wherein the controller detects a decrease in intensity of the ultraviolet light emitted from the light-emitting element based on an output signal from the first detection unit.

4. a second detection unit that is provided outside the housing, electrically connected to the controller, and detects the ultraviolet light emitted from the light-emitting element and transmitted through the liquid; 4. The liquid treatment device according to claim 3, wherein the controller determines the cause of the decrease in intensity of the ultraviolet light based on the output signal from the first detection unit and the output signal from the second detection unit.

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