Ultraviolet irradiation device

Abstract

To provide an ultraviolet irradiation device capable of suppressing degradation of an ultraviolet LED and reducing a pressure drop accompanying cooling of an ultraviolet light source by locating the ultraviolet light source in a stream of a fluid to be treated.SOLUTION: In order to effectively cool an ultraviolet light source of an ultraviolet LED and thus suppress degradation of the ultraviolet LED, an ultraviolet irradiation device is equipped with a treatment part that is a round or square cylindrical body in which a fluid to be treated flows and has an inlet port of the fluid to be treated at one end and an outlet port of the fluid to be treated on the side wall near the other end, the ultraviolet light source having a plurality of the ultraviolet LEDs put on a substrate, and a waterproof container composed of heat transfer members for housing the ultraviolet light source. An ultraviolet transmission window facing toward the inlet port of the fluid to be treated is formed in the cylindrical vessel, supported by a block plate at the cylinder end on the outlet port side, and located in the fluid to be treated.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an ultraviolet irradiation device suitable for irradiating a fluid such as a liquid with ultraviolet rays to detoxify harmful substances in the fluid, and particularly to an ultraviolet irradiation device provided with an ultraviolet light source that generates ultraviolet rays by an ultraviolet LED (UV-Light Emitting Diode).

Background Art

[0002] In this specification, harmful substances refer to microorganisms, fungi, viruses, etc. present in the fluid, as well as harmful chemical substances such as NDMA, 1,4-dioxane, 2-MIB, geosmin, formaldehyde, haloacetic acids, etc., and disinfection by-products. Detoxification means killing, inactivating, sterilizing, disinfecting, decomposing (chemical change) harmful substances, etc. Further, the fluid to be detoxified (hereinafter referred to as the treatment fluid) includes tap water, food, beverages, etc., as well as sewage.

[0003] In such ultraviolet irradiation device technology, it has been proposed to use an ultraviolet LED that emits ultraviolet rays instead of an ultraviolet mercury lamp to achieve a mercury-free environment. Further, the ultraviolet LED is formed to emit ultraviolet rays having a wavelength suitable for the harmful substances to be detoxified.

[0004] Generally, since an ultraviolet LED has a strong directivity of ultraviolet rays and it is difficult for ultraviolet rays to diffuse, various proposals have been made regarding the arrangement of the ultraviolet light source with respect to the flow path of the treatment fluid. In particular, in order to effectively irradiate the treatment fluid with ultraviolet rays, it is desirable to arrange the ultraviolet light source such that the irradiation direction of the ultraviolet rays is opposed to the flow of the treatment fluid or parallel to the flow. According to this, it is easy to lengthen the irradiation time for the treatment fluid.

[0005] Furthermore, when ultraviolet light is irradiated either opposite to or parallel to the flow of the processing fluid, it is desirable to increase the emission intensity of the ultraviolet LEDs and increase the mounting density to increase the irradiation intensity of ultraviolet light to the cross-section of the processing fluid flow path. However, increasing the emission intensity and mounting density of the ultraviolet LEDs raises concerns about performance degradation due to heat generation of the ultraviolet LEDs.

[0006] Conventionally, in order to effectively cool ultraviolet LEDs, it has been proposed to install the ultraviolet source in the flow path at the outlet end of the processing channel and cool the ultraviolet source with a high-flow processing fluid (see Patent Document 1).

[0007] According to the ultraviolet irradiation device described in Patent Document 1, a pair of thick, disc-shaped connecting members are stacked and arranged at the connection between the discharge channel, which discharges the processed fluid processed in a straight processing channel, and the processing channel. A cylindrical recess for housing an ultraviolet source is formed in one of the connecting members on the mating surface of the connecting members, and the opening of the cylindrical recess is sealed with an ultraviolet-transmitting member. On the other connecting member, on the surface opposite the ultraviolet-transmitting member, a cylindrical recess larger than the one in the first cylindrical recess is formed, and an opening for the processed fluid to flow into the bottom of this recess is provided. Furthermore, an opening communicating with the discharge channel is formed on the back side of the bottom of the cylindrical recess of one of the connecting members. In addition, a plurality of cooling channels are formed on one of the connecting members, surrounding the outer circumference of the cylindrical recess, and these cooling channels are provided to communicate the inflow opening of the processed fluid in the other connecting member with the discharge opening of the one connecting member. The ultraviolet source is housed with the ultraviolet emission surface facing the opening into which the processing fluid flows, and the substrate of the ultraviolet LED positioned at the bottom of a cylindrical recess. As a result, the ultraviolet LED of the ultraviolet source is cooled by the processing fluid flowing through multiple cooling channels formed in a pair of connecting members.

[0008] Furthermore, Patent Document 2 describes an ultraviolet irradiation device in which an ultraviolet irradiation unit is provided on the opposite side of the inflow side of the flow path through which the processed fluid flows, and ultraviolet rays are irradiated to the inflow side through a window made of a transparent material. It also describes providing a cleaning device to clean the window of the ultraviolet source at the widened diameter section on the inflow side of the flow path. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] Patent No. 6458779 [Patent Document 2] Patent No. 6721487 [Overview of the project] [Problems that the invention aims to solve]

[0010] Patent Document 1 describes a pair of disc-shaped connecting members containing ultraviolet light sources, around which a cylindrical recess is formed on the connecting surface. Multiple cooling channels are provided to circulate the processing fluid. However, the cross-section of these cooling channels is small, and their shape is U-shaped, bending to surround the outside of the ultraviolet light sources. Manufacturing cooling channels of this shape may be complicated, and at the same time, it may lead to a large pressure loss in the processing fluid. Furthermore, specific configurations for supplying power to the ultraviolet LEDs, such as the waterproof structure of the power wiring leading to the ultraviolet light sources, are not considered.

[0011] Furthermore, in Patent Document 2, the cooling surface of the ultraviolet source is only one side of the ultraviolet transmission window facing the flow path of the processing fluid, so the cooling efficiency of the ultraviolet LED is low, and therefore the effect of suppressing the degradation of the ultraviolet LED is low.

[0012] The first problem that the present invention aims to solve is to provide an ultraviolet irradiation device that can suppress the degradation of ultraviolet LEDs by placing an ultraviolet source using ultraviolet LEDs in the flow of a processing fluid, and can also suppress pressure loss associated with the cooling of the ultraviolet source.

[0013] Furthermore, the second challenge, in addition to the first challenge, is to realize a power supply for the ultraviolet source with a simple configuration.

[0014] Furthermore, the third challenge, in addition to the first and second challenges, is to reduce short paths caused by the uneven flow of the processed fluid resulting from placing the ultraviolet source within the flow of the processed fluid. [Means for solving the problem]

[0015] To solve the above problems, a first aspect of the ultraviolet irradiation device of the present invention comprises a processing unit formed as a cylindrical body with a circular or rectangular cross-section through which a processing fluid flows, having an inlet for the processing fluid at one end and an outlet for the processing fluid on a side wall near the other end, and an ultraviolet source having a plurality of ultraviolet LEDs mounted on a substrate for irradiating the processing fluid with ultraviolet light, The processing unit has an upstream end closing plate and a downstream end closing plate that detachably close the openings at both ends of the cylindrical body by flange connection, The ultraviolet light source is housed in a waterproof container, the waterproof container having a bottomed cylindrical container formed of a heat transfer member, with the substrate of the ultraviolet LED supported on the inner surface of the bottom, and an ultraviolet light-transmitting window formed of an ultraviolet light-transmitting member fitted in a watertight manner to the opening of the cylindrical container, the ultraviolet light-transmitting window positioned in the processing fluid toward the inlet of the processing fluid, and supported by a support member on a closing plate at the end of the cylindrical body on the outlet side. The support member supports the waterproof container at a position where the processing fluid supplied from the inlet flows between the outer circumference of the waterproof container and the inner wall of the cylindrical body and is discharged from the outlet. It is characterized by.

[0016] As described above, according to the first embodiment of the ultraviolet irradiation device of the present invention, the ultraviolet source is housed in a waterproof container formed of a heat transfer member and placed in the processing fluid of the processing unit. Therefore, the processing fluid supplied from the inlet flows through the cylindrical body and, upon reaching the position of the waterproof container of the ultraviolet source, flows between the outer circumference of the waterproof container and the inner wall of the cylindrical body of the processing unit and is discharged from the outlet. In other words, since the processing fluid flows over the entire outer surface of the waterproof container housing the ultraviolet source, the heat generated by the multiple ultraviolet LEDs mounted on the substrate is transferred to the processing fluid from the outer surface of the waterproof container and the ultraviolet-transmitting window. The heat from the ultraviolet LEDs is effectively cooled by the processing fluid, and the degradation of the ultraviolet LEDs can be suppressed. Furthermore, since there are no narrow sections in the flow path around the outer circumference of the waterproof container, pressure loss of the processing fluid associated with the cooling of the ultraviolet source can be suppressed.

[0017] Furthermore, because ultraviolet light is irradiated opposite to the flow of the processing fluid, the time during which ultraviolet light is irradiated to the processing fluid flowing from the inlet towards the ultraviolet-transmitting window can be extended. This improves the efficiency of ultraviolet irradiation, allowing harmful substances in the processing fluid to be effectively neutralized.

[0018] In this first embodiment, it is preferable to have the following configuration. (1) The support member may be configured to include a plurality of support members fixed to the container wall of the waterproof container, a plurality of support members fixed to the support members, and a support member that fixes the support members to the inner surface of the closing plate at the end of the cylindrical body on the outlet side. (2) The device can be configured to have a wiring conduit through which a power supply wiring is inserted into the cylindrical body of the processing unit, passing through a watertight sealing plate at the end of the cylindrical body on the outlet side, and an inlet provided at the bottom of the cylindrical container of the waterproof container, which watertightly connects the wiring conduit and the waterproof container. This allows power to be supplied to the ultraviolet source in a watertight manner and easily. (3) Preferably, an ultraviolet reflective layer is formed on the inner surface of the processing unit on the inlet side of the ultraviolet source. (4) An ultrasonic cleaner is provided at intervals on the closing plate at the end of the cylindrical body on the inlet side, and it is preferable that the ultrasonic cleaner has its ultrasonic emission surface facing the ultraviolet light-transmitting window. (5) Preferably, an ultraviolet intensity meter is positioned on the ultraviolet transmission window side of the ultrasonic cleaner to measure the luminous intensity of ultraviolet light, and the ultraviolet intensity meter has the function of measuring the luminous intensity of ultraviolet light irradiated from the ultraviolet light source and the function of measuring the luminous intensity of ultraviolet light reflected by the reflective layer.

[0019] A second aspect of the ultraviolet irradiation device of the present invention comprises a processing unit formed in a cylindrical body with a circular or rectangular cross-section through which a processing fluid flows, having an inlet for the processing fluid at one end and an outlet for the processing fluid on a side wall near the other end, and an ultraviolet source having a plurality of ultraviolet LEDs mounted on a substrate for irradiating the processing fluid with ultraviolet light, wherein the processing unit has an upstream end closing plate and a downstream end closing plate that detachably close the openings at both ends of the cylindrical body by flange connection, the ultraviolet source is housed in a waterproof container, the waterproof container is a bottomed cylindrical container formed of a heat transfer member with the substrate of the ultraviolet LEDs supported on the bottom inner surface, and an ultraviolet transmission window formed of an ultraviolet transmission member is watertightly fitted at the opening of the cylindrical container, the cylindrical container having an outer diameter smaller than the inner dimensions of the cylindrical body of the processing unit The container is formed with a rectangular or rectangular container wall, and the ultraviolet-transmitting window is positioned in the processing fluid toward the inlet of the processing fluid and supported by the downstream end closing plate via a support member, wherein the support member comprises a cylindrical partition tube supported with its center aligned with the downstream end closing plate, an annular partition plate fixed coaxially to the opening of the free end of the partition tube, and a support tube fixed coaxially to the inlet side surface of the partition plate, the waterproof container is inserted and fixed to the open end of the free end of the support tube, and a plurality of openings for the flow of the processing fluid are formed in the cylindrical walls of the partition tube and the support tube, respectively, and the periphery of the partition plate is formed to be located on the inlet side of the discharge port and to be in contact with the cylindrical wall surface with a gap between them.

[0020] The flow of the processing fluid and the cooling effect of the ultraviolet source in this configuration will be explained in detail. First, the processing fluid flowing from the processing section to the discharge section is blocked by the ultraviolet-transmitting window of the ultraviolet source and flows into the region between the support cylinder supporting the ultraviolet source and the cylindrical wall of the discharge section. The processing fluid that has flowed into this region is blocked by the partition plate and flows into the interior of the support cylinder through multiple openings formed in the support cylinder and flows along the outer surface of the bottom of the waterproof container on which the ultraviolet LED substrate is supported. As a result, the heat generated by the ultraviolet LED is effectively cooled by the processing fluid via the ultraviolet-transmitting window, the cylindrical wall of the waterproof container, and the outer surface of the bottom.

[0021] The processing fluid that cools the ultraviolet LED flows into the interior of the partition cylinder from the opening of the partition plate opened in the support cylinder. The processing fluid flowing into the partition cylinder flows from the plurality of openings formed in the partition cylinder into the annular region formed between the partition cylinder and the cylinder body of the processing unit, and then flows into the discharge port from that region and is discharged. Further, the region from the support cylinder to the partition cylinder and the annular region formed by the partition cylinder and the cylinder body of the processing unit act as a rectification region for rectifying the processing fluid disturbed by the waterproof container of the ultraviolet source. Therefore, according to the second aspect, the configuration of arranging the ultraviolet source in the flow of the processing fluid can be simplified, and since there are no narrow portions in the flow path flowing around the outer periphery of the waterproof container, the pressure loss of the processing fluid associated with the cooling of the ultraviolet source can be kept low. In addition, it is possible to reduce a short path in which most of the main flow of the processing fluid in the processing unit is biased and flows through the gap between the ultraviolet source close to the discharge port and the cylinder body, and flows into the discharge port. As a result, it is possible to reduce the non-uniform flow of the processing fluid with respect to the ultraviolet rays irradiated from the ultraviolet source, and improve the irradiation efficiency of the ultraviolet rays on the processing fluid.

[0022] Moreover, according to the second aspect of the present invention, since the partition cylinder is fixed to the downstream side closing plate, the partition plate is fixed and supported at the other end of the partition cylinder, and the peripheral edge of the partition plate is provided with a gap with respect to the cylinder wall of the processing unit, even if the partition plate and the partition cylinder are deformed due to thermal expansion or the like, they can freely deform with respect to the cylinder wall of the processing unit, so that unexpected stress applied to both can be reduced.

[0023] Furthermore, since the partition plate is not fixed to the cylinder wall of the processing unit, when removing and maintaining the ultraviolet source, etc., the downstream side closing plate can be removed from the processing unit, and the ultraviolet source housed in the waterproof container can be separated from the processing unit together with the partition plate, so that maintenance of members such as the ultraviolet source can be easily performed.

[0024] Furthermore, a cylindrical sliding cylinder having an outer peripheral surface flush with the peripheral edge may be fixedly provided at the peripheral edge of the partition plate. According to this, the length in the cylinder axis direction of the gap formed between the peripheral edge of the partition plate and the cylinder wall of the processing unit can be increased, so that the flow of the processing fluid short-circuiting from this gap to the discharge port can be further suppressed. As a result, more processing fluid can contact the disc-shaped outer surface of the waterproof container located inside the support cylinder, so that the cooling effect of the ultraviolet light source can be enhanced.

[0025] Also, the ultraviolet irradiation device according to the second aspect of the present invention may have the cylindrical body of the processing unit arranged vertically or horizontally. When arranged vertically, it is preferable to locate the inlet of the processing fluid at the lower part and the outlet at the upper part, and install the waterproof container containing the ultraviolet light source in a state of being suspended from the downstream end closing plate. On the other hand, when arranged horizontally, the waterproof container containing the ultraviolet light source will be supported in a cantilevered manner by the downstream end closing plate via the partition cylinder, the partition plate and the support cylinder which are support members. In this case, the entire support member may be deflected by the weight of the waterproof container containing the ultraviolet light source and the support member. In that case, it is preferable to provide rollers that roll along the axial direction of the processing unit cylinder body at appropriate positions on the peripheral edge of the partition plate between the peripheral edge of the partition plate and the inner wall of the processing unit cylinder body, and provide roller receivers for supporting these rollers on the inner wall.

[0026] Also, the ultraviolet light source can be configured to include a wiring pipe through which the power supply wiring inserted into the support cylinder penetrates the downstream end closing plate in a watertight manner, and an inlet provided through the bottom of the cylindrical container of the waterproof container and connecting the wiring pipe and the waterproof container in a watertight manner. Further, in order to increase the amount of light of the ultraviolet light irradiated to the processing fluid, it is preferable to form an ultraviolet reflection layer on the inner wall surface of the processing unit on the inlet side of the ultraviolet light source.

[0027] Furthermore, an ultrasonic cleaner can be provided, suspended from the support member supported by the closing plate at the end of the cylindrical body on the outlet side. The ultrasonic cleaner is positioned with a gap between it and the closing plate at the end of the cylindrical body on the inlet side, with its ultrasonic emission surface facing the ultraviolet-transmitting window. This configuration allows for the removal of foreign matter in the processing fluid adhering to the ultraviolet-emitting surface of the ultraviolet-transmitting window and the inner surface of the cylindrical wall and reflective layer of the processing section by irradiating them with ultrasonic waves.

[0028] Furthermore, it is preferable to position an ultraviolet intensity meter on the ultraviolet transmission window side of the ultrasonic cleaner to measure the intensity of ultraviolet light, and to position the ultraviolet intensity meter to have the function of measuring the intensity of ultraviolet light irradiated from the ultraviolet light source and the function of measuring the intensity of ultraviolet light reflected by the reflective layer.

[0029] Furthermore, in order to solve the second problem, it is preferable that, similar to the first aspect of the present invention, the wiring conduit is inserted into the support cylinder, passing through the downstream end closing plate in a watertight manner, and through which power wiring is inserted, and that an inlet is provided at the bottom of the cylindrical container of the waterproof container to watertightly connect the wiring conduit and the waterproof container. This makes it possible to supply power to the ultraviolet source in a watertight manner and with a simple configuration. In the case where a structure is adopted in which the wiring conduit through which the power wiring is inserted is fixed to the downstream end closing plate, and it is necessary for the wiring conduit to absorb the thermal expansion of the support member of the waterproof container, it is preferable that the connection part of the inlet be a connecting structure such as a universal joint that can expand and contract in the direction of the pipe axis. Alternatively, it is preferable that the structure of the part in which the wiring conduit passes through the downstream end closing plate is a seal structure that allows the wiring conduit to slide in the direction of penetration. [Effects of the Invention]

[0030] The present invention provides an ultraviolet irradiation device that can suppress the degradation of ultraviolet LEDs by placing the ultraviolet source in the flow of the processing fluid, and can also suppress pressure loss associated with the cooling of the ultraviolet source. In addition, the power supply for the ultraviolet source can be realized with a simple configuration. Furthermore, it can reduce short paths caused by the uneven flow of the processing fluid resulting from placing the ultraviolet source in the flow of the processing fluid. [Brief explanation of the drawing]

[0031] [Figure 1] This is a longitudinal cross-sectional view of a first embodiment of the ultraviolet irradiation device of the present invention. [Figure 2] This is a longitudinal cross-sectional view of a second embodiment of the ultraviolet irradiation device of the present invention. [Figure 3] This is a cross-sectional view of a portion of the ultraviolet intensity meter of the second embodiment. [Figure 4] This is a longitudinal cross-sectional view of a third embodiment of the ultraviolet irradiation device of the present invention. [Modes for carrying out the invention]

[0032] (First Embodiment)

[0033] The present invention will now be described based on embodiments. Figure 1 shows a longitudinal cross-sectional view of a first embodiment of the ultraviolet irradiation device of the present invention. As shown in the figure, this embodiment is formed having a cylindrical body 1 made of stainless steel through which a processing fluid flows. Both ends of the body 1 are closed by stainless steel closure plates 2 and 3, which can be attached and detached by flange joints. An inlet 4 for the processing fluid is provided in the closure plate 2 at the upstream end (the lower end of the body 1 in the figure), and an outlet 5 is provided in the cylindrical wall of the body 1 near the closure plate 3 at the downstream end. This embodiment also includes an ultraviolet source 10 having a plurality of ultraviolet LEDs 12 mounted on a substrate 11 for irradiating the processing fluid with ultraviolet light.

[0034] The ultraviolet light source 10 is housed in a stainless steel waterproof container 13 made of a heat transfer material. The waterproof container 13 has a substrate 11 of an ultraviolet LED 12 supported on the inner bottom surface of a bottomed cylindrical container 14, and an ultraviolet light-transmitting window 15 made of an ultraviolet light-transmitting material is fitted into the opening of the cylindrical container 14. The ultraviolet light-transmitting window 15 is positioned in the processing fluid with the processing fluid inlet 4 facing the processing fluid, and is supported by a support member 20 on the closing plate 3 at the end of the cylindrical body on the outlet 5 side. The support member 20 is made of stainless steel and consists of a plurality of support members 18 fixed to the container wall of the cylindrical container 14, a plurality of plate-shaped support members 27 connected to the support members 18 with bolts or the like, and a support member 28 that fixes the support members 27 to the inner surface of the closing plate 3 with bolts or the like. In addition to stainless steel, the waterproof container 13 can be made of a metal that has better heat transfer properties and is not affected by the processing fluid, such as lead-free copper alloy (gunmetal) or copper. Furthermore, the support 27 may be constructed using a strip-shaped plate, a member made by bending the plate into an L-shape, or a round bar.

[0035] Furthermore, in this embodiment, a stainless steel wiring conduit 30 is inserted into the cylinder of the cylindrical body 1, passing through the sealing plate 3 in a watertight manner. Electrical wires, such as cables that supply power to the ultraviolet source LED 12, are inserted through the wiring conduit 30. A circular base plate 33 is welded to the portion where the wiring conduit passes through the sealing plate 3, and a sealing member such as an O-ring is interposed at the contact surface between the base plate 33 and the sealing plate 3, and the two are secured by tightening with bolts or the like.

[0036] The wiring conduit 30, inserted into the cylindrical body 1 of the processing unit, is connected via a universal joint 32 to an inlet 31 formed by penetrating the bottom of the cylindrical container 14. The universal joint 32 is used to absorb the displacement of the waterproof container 13 in the axial direction of the wiring conduit 30 when the support member 20 and support cylinder 24 expand due to heat. Alternatively, instead of the universal joint 32, the structure of the part where the wiring conduit 30 penetrates the closing plate 3 can be made into a seal structure that allows the wiring conduit 30 to slide in the penetrating direction.

[0037] In this embodiment, as is commonly practiced, an ultraviolet reflective layer 40 is provided on the inner surface of the cylindrical body 1. The reflective layer 40 is made of PTFE (polytetrafluoroethylene), which is resistant to degradation by ultraviolet light and has excellent reflectivity. As a result, even if the ultraviolet light irradiated from the ultraviolet source 10 is refracted or bent by the processing fluid, the probability of it being reflected by the reflective layer 40 and irradiated back onto the processing fluid increases. Consequently, the amount of ultraviolet light irradiated onto the processing fluid can be increased, effectively neutralizing harmful substances contained in the processing fluid.

[0038] As described above, in this embodiment, since the ultraviolet source 10 is housed in a waterproof container 13 made of a heat transfer member and placed in the processing fluid of the cylindrical body 1, the processing fluid supplied from the inlet 4 flows through the cylindrical body and, upon reaching the position of the ultraviolet source 10 in the waterproof container 13, flows between the outer circumference of the waterproof container 13 and the inner wall of the cylindrical body 1 and is discharged from the outlet 5. In other words, since the processing fluid flows around the outer circumference of the waterproof container 13 in which the ultraviolet source 10 is housed, the heat generated by the multiple ultraviolet LEDs 12 mounted on the substrate 11 is transferred to the processing fluid from the outer surface of the waterproof container 13 and the ultraviolet-transmitting window 15, and the heat of the ultraviolet LEDs 12 is effectively cooled by the processing fluid. As a result, the degradation of the ultraviolet LEDs 12 can be suppressed.

[0039] Furthermore, since ultraviolet light is irradiated opposite to the flow of the processing fluid, the irradiation time of the processing fluid flowing from the inlet 4 toward the ultraviolet-transmitting window 15 can be extended, improving the irradiation efficiency of ultraviolet light and effectively neutralizing harmful substances in the processing fluid. In addition, according to this embodiment, even if the ultraviolet source 10 is located in the processing fluid, power can be easily supplied to the ultraviolet source 10.

[0040] Furthermore, in this embodiment, by appropriately adjusting and securing the distance between the ultraviolet source 10 and the outlet 5, the influence of flow turbulence (non-uniformity) caused by the outlet 5 on the flow state inside the cylindrical body 1 can be reduced to a practically acceptable level. As a result, short paths where the main flow of the processing fluid in the processing unit is biased towards the outlet 5 side of the ultraviolet source 10 can be reduced. Consequently, it is possible to reduce the non-uniform flow of the processing fluid in response to ultraviolet light irradiated from the ultraviolet source 10 and improve the irradiation efficiency of the processing fluid with ultraviolet light. (Second Embodiment)

[0041] Next, a second embodiment of the present invention will be described with reference to Figure 2. The differences between this embodiment and the first embodiment shown in Figure 1 are that the support structure of the waterproof container 13 housing the ultraviolet source 10 is different, and that an ultrasonic cleaner 41 for cleaning the ultraviolet transmission window 15 of the ultraviolet source 10 and an ultraviolet intensity meter 50 are provided.

[0042] As shown in the figure, the ultraviolet irradiation device of this embodiment is formed having a cylindrical stainless steel treatment unit 1 through which a treatment fluid flows. Both ends of the cylindrical treatment unit 1 are closed by stainless steel closure plates 2 and 3, which can be attached and detached by flange joints. An inlet 4 for the treatment fluid is provided in the closure plate 2 at the upstream end, and an outlet 5 is provided in the cylindrical wall of the cylindrical treatment unit 1 near the closure plate 3 at the downstream end.

[0043] The ultraviolet source 10 is formed by comprising multiple ultraviolet LEDs 12 mounted on a substrate 11. The ultraviolet source 10 is watertightly housed in a stainless steel waterproof container 13. The waterproof container 13 is not limited to stainless steel; a metal with better heat conductivity than stainless steel and that is not affected by the processing fluid may be used, such as lead-free copper alloy (gunmetal), copper, etc. The waterproof container 13 is formed by having a flat, cup-shaped, bottomed cylindrical container 14, and an ultraviolet-transmitting window 15 made of quartz glass or the like, which is an ultraviolet-transmitting material, is watertightly fitted to the opening of the cylindrical container 14. For example, a sealing packing such as an O-ring is interposed between the inner surface of the cylindrical container 14 and the outer surface of the ultraviolet-transmitting window 15 to watertightly join them to the cylindrical container 14. The watertight joining of the cylindrical container 14 and the ultraviolet-transmitting window 15 is not limited to this, and various configurations can be applied. In addition, multiple heat dissipation fins 17 are provided on the outer surface of the bottom 16 of the cylindrical container 14. The outer shape of the waterproof container 13 formed in this manner is formed with a circular or rectangular container wall that is smaller than the inner dimensions of the cylindrical body 1 of the processing unit.

[0044] The ultraviolet light source 10 housed in the waterproof container 13 is supported on the closure plate 3 via a stainless steel support member 20. The support member 20 is formed by a cylindrical partition tube 21 supported with its center aligned with the closure plate 3, an annular partition plate 22 fixed to the opening at the free end of the partition tube 21, for example by welding, and a support tube 24 fixed coaxially with the partition tube 21 to the inlet 4 side surface of the partition plate 22. The partition tube 21 has an annular flange member 22 fixed to its end, facing the closure plate 3, and is fastened and secured with bolts or the like with an O-ring packing interposed between the flange member 22 and the closure plate 3. The partition plate 23 has an opening in its center corresponding to the opening of the partition tube 21, and is formed in an annular shape such that its periphery is in contact with the inner wall of the cylindrical body 1 of the processing unit. The waterproof container 13 is inserted into the open end, which is the free end of the support tube 24, and is supported, for example, via a fixing material. Furthermore, multiple openings 25 are formed in the walls of the partition cylinder 21 and the support cylinder 24, respectively, through which the processing fluid flows.

[0045] Furthermore, the periphery of the partition plate 22 is positioned on the inlet 4 side of the discharge port 5 and is formed in such a shape that it contacts the cylindrical wall surface of the cylindrical body 1 of the processing unit with a gap between them. This allows the difference in thermal expansion between the partition cylinder 21 and the partition plate 22 and the cylindrical wall of the cylindrical body 1 of the processing unit to be absorbed. In addition, in this embodiment, a cylindrical sliding cylinder 26 having an outer peripheral surface flush with the periphery is fixed to the periphery of the partition plate 22. This allows the length in the axial direction of the gap formed between the periphery of the partition plate 22 and the cylindrical wall of the cylindrical body 1 of the processing unit to be increased, thereby further suppressing the flow of processing fluid that short-passes from this gap to the discharge port 5. As a result, more processing fluid can come into contact with the disc-shaped outer surface of the waterproof container 13 located inside the support cylinder 24, thereby increasing the cooling effect of the ultraviolet source 10.

[0046] Furthermore, in this embodiment, a stainless steel wiring conduit 30 is inserted into the support cylinder 21, passing through the closure plate 3 in a watertight manner. Electrical wires, such as cables that supply power to the ultraviolet LED source, are inserted through the wiring conduit 30. A circular base plate 33 is welded to the portion of the wiring conduit 30 that penetrates the closure plate 3, and a sealing member such as an O-ring is interposed at the contact surface between the base plate 33 and the closure plate 3, and the conduit is secured by tightening with bolts or the like. The wiring conduit 30 inserted into the partition cylinder 21 is connected to an inlet 31 formed by passing through the bottom of the cylindrical container 14 via a universal joint 32. The universal joint 32 is used to absorb the displacement of the waterproof container 13 in the axial direction of the wiring conduit 30 when the support member 20 and the support cylinder 24 expand due to heat. Alternatively, instead of the universal joint 32, it is also possible to adopt a sealing structure that allows the wiring conduit 30 to slide in the penetrating direction for the portion of the wiring conduit 30 that penetrates the closure plate 3.

[0047] The reflective layer 40 in this embodiment is the same as in the first embodiment, so its description will be omitted. The ultrasonic cleaner 41 is commonly used in ultraviolet irradiation devices. The ultrasonic cleaner 41 is formed by housing an ultrasonic generator in a waterproof container having a rectangular parallelepiped or cylindrical outer shell, and is suspended by a plurality of support members 46 fixed to the lower surface of the partition plate 23, similar to the support cylinder 24 that supports the waterproof container 14. The ultrasonic cleaner 41 is positioned at a certain distance from the upstream closing plate 2 so as not to obstruct the flow of the processing fluid. Power for the ultrasonic cleaner 41 is supplied via a power cable 47. The power cable 47 is led to the outside via a universal joint 48 that penetrates the downstream closing plate 3 and connected to the power supply.

[0048] Furthermore, in this embodiment, an ultraviolet intensity meter 50 is provided to measure the amount of ultraviolet radiation irradiated onto the processing fluid. The ultraviolet intensity meter 50 is positioned so as not to obstruct the ultrasonic irradiation route from the ultrasonic cleaner 41 to the ultraviolet transmission window. Therefore, it is not shown in Figure 2, which is a cross-sectional view of the cylindrical body 1 of the processing unit, and is shown with dashed lines in that figure. Figure 3 shows a detailed cross-sectional view of the ultrasonic cleaner 41. As shown in Figure 3, the ultraviolet intensity meter 50 is housed in a cylindrical sensor sleeve 51 and is provided penetrating the cylindrical body 1 of the processing unit. The ultraviolet intensity meter 50 has a pair of sensors 53 housed in a sensor tube 55. The pair of sensors 53 consists of a sensor 53a that measures ultraviolet radiation directly irradiated from the ultraviolet source 10 and a sensor 53b that measures ultraviolet radiation reflected by the reflective layer 40. However, for the sake of simplicity, unless the difference is to be clarified, the sensors will hereinafter simply be referred to as "sensor 53 in particular." As is widely known, the sensor 53 is formed by sealing a photoconversion material that converts ultraviolet light into visible light in a glass tube. The sensor 53 and the tip of the signal line 54 are covered by the sensor cylinder 55 and slidably inserted into the protective tube 56. The measurement signal from the sensor 53 is led to the outside by the signal line 54, such as a fiberglass, and guided to a light meter (not shown).

[0049] The sensor sleeve 51 of the UV intensity meter 50, formed in this manner, is watertightly supported by a support sleeve 57 that penetrates the cylindrical wall of the processing unit's cylindrical body 1. The end opening of the support sleeve 57 is closed by a removable cover 58. The cover 58 is also provided with an outlet for the signal wire 54. By removing the cover 58, the sensor cylinder 55, including the sensor 53 and the signal wire 54, can be pulled out from the protective tube 56 to perform necessary inspections and maintenance.

[0050] The sensor cylinder 55 has measurement windows 55a and 55b that pass through along the axial direction to allow ultraviolet light from the object being measured to pass through. The measurement window 55a of one sensor 55 is shaped to allow all of the ultraviolet LEDs 12 of the ultraviolet source 10 to pass through, while the measurement window 55b of the other sensor 55b is designed to measure the amount of ultraviolet light reflected from a predetermined surface of the reflective layer 40. In other words, the shape of the measurement window 55b is shaped to allow a certain area of ​​the reflective layer 40 to pass through.

[0051] The flow of the processing fluid and the cooling effect of the ultraviolet source 10 in the characteristic configuration of this embodiment, as described above, will now be explained in detail. First, the processing fluid flowing in from the inlet 4 is blocked by the ultraviolet-transmitting window 15 of the ultraviolet source 10 and flows into the region between the support cylinder 24 that supports the ultraviolet source 10 and the cylindrical wall of the processing unit cylinder 1. The processing fluid that has flowed into this region is blocked by the partition plate 23 and flows into the interior of the support cylinder 24 through a plurality of openings 25 formed in the support cylinder 24 and flows along the outer surface of the waterproof container 13 on which the substrate 11 of the ultraviolet LED 12 is supported. Since heat-conducting fins 17 are provided on the outer surface, heat is effectively dissipated to the processing fluid. In addition, the heat generated by the ultraviolet LED 12 is effectively cooled by the processing fluid through the ultraviolet-transmitting window 15 and the cylindrical wall of the waterproof container 13.

[0052] The processing fluid cooled by the ultraviolet LED 12 flows into the partition cylinder 21 through an opening in the partition plate 23, which is opened inside the support cylinder 24. The processing fluid that flows into the partition cylinder 21 flows through a plurality of openings 25 formed in the partition cylinder 21 into an annular region formed between the partition cylinder 21 and the cylindrical body of the processing unit 1, and from that region flows into the outlet 5 and is discharged. In other words, the region from the support cylinder 24 to the partition cylinder 21, and the annular region formed between the partition cylinder 21 and the cylindrical body of the processing unit 1, act as a rectifying region that rectifies the processing fluid disturbed by the waterproof container 13 of the ultraviolet source 10. Therefore, according to this embodiment, the configuration in which the ultraviolet source 10 is placed in the flow of the processing fluid can be simplified, and pressure loss can be kept low. In addition, it is possible to reduce short paths where the main flow of the processing fluid in the processing unit is biased towards the outlet 5 side of the ultraviolet source 10. As a result, it is possible to reduce the non-uniform flow of the processing fluid in response to ultraviolet light irradiated from the ultraviolet light source 10, thereby improving the irradiation efficiency of the processing fluid with ultraviolet light.

[0053] Furthermore, according to the configuration of the support member 20 of this embodiment, the partition cylinder 21 is fixed to the closing plate 3 of the cylindrical body 1 of the processing unit, and the partition plate 23 is fixed and supported to the other end of the partition cylinder 21, with the periphery of the partition plate 23 being in contact with the cylindrical wall of the cylindrical body 1 of the processing unit via a gap. Therefore, even if the partition cylinder 21 and the partition plate 23 deform in the axial direction of the cylindrical body 1 of the processing unit due to thermal expansion or the like, they can deform freely relative to the cylindrical body of the cylindrical body 1 of the processing unit, thus reducing the stress applied to both. In addition, by minimizing the gap between the edge of the partition plate 23 and the cylindrical wall of the cylindrical body 1 of the processing unit, the flow rate of the processing fluid that short-passes through that gap to the discharge port 5 can be suppressed. Furthermore, if an annular cylinder is fixed to the edge of the partition plate 23, the flow of the processing fluid that short-passes through that gap to the discharge port 5 can be further suppressed by increasing the length in the axial direction of the gap formed between it and the cylindrical wall of the cylindrical body 1 of the processing unit.

[0054] Next, the operation of the ultraviolet irradiation device of this embodiment will be described. Basically, the processing fluid flowing in from the inlet 4 flows upward in the cylindrical body 1 of the processing unit as shown in the figure. In this embodiment, the flow is slightly obstructed by the ultrasonic cleaner 41 and the ultraviolet intensity meter 50 placed in the processing fluid, but as the fluid rises inside the cylindrical body 1 of the processing unit, ultraviolet light is irradiated from the ultraviolet transmission window 15 of the ultraviolet source 10. Since the ultraviolet light emitted from the ultraviolet LED 12 is highly directional, it is irradiated parallel to the flow of the processing fluid. Therefore, the time the processing fluid flowing toward the ultraviolet transmission window 15 is irradiated is proportional to the length from the inlet to the ultraviolet transmission window 15 and inversely proportional to the flow velocity of the processing fluid. Thus, the amount of ultraviolet light irradiated to the processing fluid can be adjusted by changing the length of the cylindrical body 1 of the processing unit and the flow velocity of the processing fluid. In addition, the amount of ultraviolet light irradiated can be adjusted by adjusting the ultraviolet irradiation intensity of the ultraviolet LED 12.

[0055] The processing fluid rising inside the cylindrical body 1 of the processing unit is blocked by the ultraviolet-transmitting window 15 of the ultraviolet source 10 and flows into the region between the support cylinder 24 supporting the ultraviolet source 10 and the cylindrical wall of the cylindrical body 1 of the processing unit, as shown by arrow 44 in the figure. This flow is blocked by the partition plate 23 and flows into the interior of the support cylinder 24 through a plurality of openings 25 formed in the support cylinder 24. The processing fluid that has flowed into the interior of the support cylinder 24 flows along the upper bottom outer surface of the waterproof container 13 in the figure, on which the substrate 11 of the ultraviolet LED 12 is supported. As a result, the processing fluid comes into contact with the heat dissipation fins 17 of the waterproof container 13 and effectively exchanges heat, cooling the heat generated by the ultraviolet LED 12. The processing fluid that has cooled the ultraviolet LED 12 flows into the interior of the partition cylinder 21 through the central opening of the partition plate 23 and flows through a plurality of openings 25 formed in the partition cylinder 21, between the partition cylinder 21 and the cylindrical wall of the cylindrical body 1 of the processing unit, as shown by arrow 45 in the figure, and is discharged from the outlet 5.

[0056] As described above, in the ultraviolet irradiation device of this embodiment, the ultraviolet source 10 is housed in a waterproof container 13 made of a heat transfer member and placed within the flow path of the processing fluid. Therefore, the heat generated by the multiple ultraviolet LEDs 12 mounted on the substrate 11 is cooled by the processing fluid via the waterproof container 13. The region formed by the partition plate 23 and the partition cylinder 21 acts as a flow straightening region for the processing fluid from the cylindrical support cylinder 24 to the outlet. Thus, according to this embodiment, the configuration in which the ultraviolet source 10 is placed in the flow of the processing fluid can be simplified, and pressure loss can be suppressed. Furthermore, compared to the first embodiment, since a large portion of the main flow of the processing fluid in the processing unit passes through the gap between the ultraviolet source 10 and the cylindrical body 1 near the outlet 5, short paths that flow unevenly towards the outlet 5 can be reduced. Therefore, it is possible to reduce the uneven flow of the processing fluid in relation to the ultraviolet light irradiated from the ultraviolet source 10 and improve the irradiation efficiency of ultraviolet light on the processing fluid.

[0057] Furthermore, according to this embodiment, the ultraviolet intensity of the ultraviolet source 10 and the ultraviolet intensity from the reflective layer 40 can be measured in real time, so the amount of ultraviolet irradiation to the processing fluid can be appropriately controlled. Moreover, if various foreign substances contained in the processing fluid adhere to the ultraviolet emission surface of the ultraviolet transmission window 15, the inner surface of the cylindrical wall of the processing unit 1, and the surface of the reflective layer 40, the ultraviolet transmittance and reflectance will decrease. Therefore, the ultrasonic cleaner 41 is operated as needed or periodically to emit ultrasonic waves from the top surface as shown in the figure, irradiating the outer surface of the ultraviolet transmission window 15 and the surface of the reflective layer 40 with ultrasonic waves, and removing foreign substances adhering to these surfaces by vibrating them with ultrasonic waves.

[0058] Furthermore, the ultraviolet source 10, waterproof container 13, and ultrasonic cleaner 41 require maintenance as needed. However, according to this embodiment, the entire ultraviolet source 10, waterproof container 13, and ultrasonic cleaner 41 can be removed from the cylindrical body 1 for maintenance by detaching the flange portion of the closing plate 3 from the cylindrical body 1 and pulling out the support member 20.

[0059] In this embodiment, considering maintenance of each part inside the cylindrical body 1, the entire ultraviolet source 10, waterproof container 13, and ultrasonic cleaner 41 can be easily pulled out by removing the flange portion of the closing plate 3 and pulling up the support member 20. Therefore, considering the ease of maintenance, it is preferable to arrange the cylindrical body of the processing unit 1 vertically. However, the cylindrical body of the processing unit 1 may also be arranged horizontally. However, if it is arranged horizontally, the waterproof container 13 containing the ultraviolet source 10 and the ultrasonic cleaner 41 will be cantilevered to the closing plate 3 via the support member 20, and the entire support member 20 may bend under the weight of the ultraviolet source 10, waterproof container 13, ultrasonic cleaner 41, and support member 20. In that case, it is preferable to provide rollers and roller supports that roll along the axial direction of the processing unit 1 at appropriate locations in the circumferential direction between the periphery of the partition plate 23 and the inner wall of the cylindrical body of the processing unit 1. (Third embodiment)

[0060] Figure 4 shows a cross-sectional view of a third embodiment of the present invention. The difference between this embodiment and the first embodiment is the addition of an ultrasonic cleaner 41 and an ultraviolet intensity meter 50. Specifically, the ultrasonic cleaner 41 is fixed to the lower end of a support member 61, which is an extension of a support member 20 that supports the waterproof container 13 containing the ultraviolet source 10, and is held inside the cylindrical body 1. In addition, an ultraviolet intensity meter 50 is provided, passing through the cylindrical body 1. The basic configuration of the ultraviolet irradiation device is the same as that of the first embodiment, and the ultrasonic cleaner 41 and ultraviolet intensity meter 50 are the same as those of the second embodiment, so the parts that are the same as those embodiments will not be described.

[0061] Although the present invention has been described above based on embodiments, it is clear that the present invention is not limited to these embodiments and can be modified in various ways, and such modifications are included within the scope of the claims of the present invention. [Explanation of Symbols]

[0062] 1 cylinder 2 Upstream blocking plate 3 Downstream blocking plate 4 Inlet 5 Outlet 10 UV source 11 circuit boards 12 UV LED 13 Waterproof container 14. Cylindrical container 15 UV-transmitting window 20 Support members 21 Bulkhead tube 23 Partition plate 24 Support tube 25 Aperture 26 Sliding tube 30 Raceway 31 Inlet 32 Universal Fittings 40 reflective layer 41 Ultrasonic cleaner 50 UV Intensity Meter 51 Sensor sleeve 53a, b Sensor 54 signal line 55 Sensor tube

Claims

1. The processing unit comprises a cylindrical body formed in a circular or rectangular cross-section through which a processing fluid flows, with an inlet for the processing fluid at one end and an outlet for the processing fluid on a side wall near the other end, and an ultraviolet light source having a plurality of ultraviolet LEDs mounted on a substrate for irradiating the processing fluid with ultraviolet light. The processing unit has an upstream end closing plate and a downstream end closing plate that detachably close the openings at both ends of the cylindrical body by flange connection, The ultraviolet light source is housed in a waterproof container. The waterproof container has a bottomed cylindrical container formed of a heat transfer member, with the substrate of the ultraviolet LED supported on the inner surface of the bottom, and an ultraviolet-transmitting window formed of an ultraviolet-transmitting member fitted in a watertight manner to the opening of the cylindrical container, with the ultraviolet-transmitting window positioned in the processing fluid toward the inlet of the processing fluid, and supported by a support member on the closing plate at the end of the cylindrical body on the outlet side. The support member supports the waterproof container at a position where the processing fluid supplied from the inlet flows between the outer circumference of the waterproof container and the inner wall of the cylindrical body and is discharged from the outlet.

2. The ultraviolet irradiation device according to claim 1, characterized in that the support member comprises a plurality of support members fixed to the container wall of the waterproof container, a plurality of support members fixed to the support members, and a support member that fixes the support members to the inner surface of the closing plate at the end of the cylindrical body on the outlet side.

3. Furthermore, the ultraviolet irradiation device according to claim 1 is characterized in that it is further provided with a wiring tube that is inserted into the cylindrical body of the processing unit, passing through a watertight closure plate at the end of the cylindrical body on the outlet side, and through which power wiring is inserted, and an inlet provided at the bottom of the cylindrical container of the waterproof container, which watertightly connects the wiring tube and the waterproof container.

4. The ultraviolet irradiation device according to claim 1, characterized in that an ultraviolet reflective layer is formed on the inner surface of the processing unit on the inlet side of the ultraviolet source.

5. The ultraviolet irradiation device according to claim 1, wherein an ultrasonic cleaner is provided at intervals on the closing plate at the end of the cylindrical body on the inlet side, and the ultrasonic cleaner has its ultrasonic emission surface facing the ultraviolet light-transmitting window.

6. The ultraviolet irradiation device according to claim 5, wherein an ultraviolet intensity meter is positioned on the ultraviolet transmission window side of the ultrasonic cleaner to measure the luminous intensity of ultraviolet light, and the ultraviolet intensity meter has the function of measuring the luminous intensity of ultraviolet light irradiated from the ultraviolet light source and the function of measuring the luminous intensity of ultraviolet light reflected by the reflective layer.

7. The processing unit comprises a cylindrical body formed in a circular or rectangular cross-section through which a processing fluid flows, with an inlet for the processing fluid at one end and an outlet for the processing fluid on a side wall near the other end, and an ultraviolet light source having a plurality of ultraviolet LEDs mounted on a substrate for irradiating the processing fluid with ultraviolet light. The processing unit has an upstream end closing plate and a downstream end closing plate that detachably close the openings at both ends of the cylindrical body by flange connection, The ultraviolet light source is housed in a waterproof container. The waterproof container has a bottomed cylindrical container made of a heat transfer member, with the substrate of the ultraviolet LED supported on the inner surface of the bottom, and an ultraviolet-transmitting window made of an ultraviolet-transmitting member fitted in a watertight manner at the opening of the cylindrical container. The cylindrical container is formed having a circular or rectangular container wall whose outer shape is smaller than the inner dimensions of the cylindrical body of the processing unit, and is supported by the downstream end closing plate via a support member, with the ultraviolet-transmitting window positioned in the processing fluid toward the inlet of the processing fluid. The support member comprises a cylindrical partition tube supported with its center aligned with the downstream end closing plate, an annular partition plate fixed coaxially to the opening at the free end of the partition tube, and a support tube fixed coaxially to the inlet side surface of the partition plate, and the waterproof container is inserted and fixed into the open end at the free end of the support tube. Multiple openings are formed in the walls of the partition cylinder and the support cylinder, respectively, through which the processing fluid flows. The peripheral edge of the partition plate is positioned on the inlet side of the outlet and is formed in such a shape that it contacts the cylindrical wall surface with a gap in between.

8. The ultraviolet irradiation device according to claim 7, characterized in that the partition plate is formed having a cylindrical sliding cylinder having an outer peripheral surface flush with the periphery.

9. The ultraviolet light source includes a wiring conduit through which the power supply wiring is inserted, which penetrates the downstream end closing plate in a watertight manner and is inserted into the support cylinder, The ultraviolet irradiation device according to claim 7, characterized in that it is provided with an inlet that penetrates the bottom of the cylindrical container of the waterproof container and connects the wiring pipe and the waterproof container in a watertight manner.

10. The ultraviolet irradiation device according to claim 7, characterized in that an ultraviolet reflective layer is formed on the inner surface of the processing unit on the inlet side of the ultraviolet source.

11. The ultrasonic cleaner is suspended and supported by the support member which is supported by the closing plate at the end of the cylindrical body on the outlet side, The ultraviolet irradiation device according to claim 7, characterized in that the ultrasonic cleaner has an ultrasonic emission surface facing the ultraviolet-transmitting window and is positioned at a distance from the closing plate at the end of the cylindrical body on the inlet side.

12. An ultraviolet intensity meter is positioned on the ultraviolet transmission window side of the ultrasonic cleaner to measure the intensity of ultraviolet light. The ultraviolet irradiation device according to claim 7, characterized in that the ultraviolet intensity meter has a function for measuring the luminous intensity of ultraviolet light irradiated from the ultraviolet light source and a function for measuring the luminous intensity of ultraviolet light reflected by the reflective layer.

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