UV irradiation device

Abstract

Provided is a UV irradiation device that can accurately and appropriately control the UV irradiation amount of UV lamps so as to satisfy a target irradiation amount while compensating for differences in UV irradiation efficiency occurring due to lighting places lit by the UV lamps. The present invention is a UV irradiation device 1 that irradiates a fluid (primary pure water W) with UV light and comprises: a plurality of UV lamps L that are disposed in a cylinder C and irradiate the fluid with UV light; a lighting place control unit 13 and a current value control unit 14 that respectively control the lighting place P and the current value VC of each UV lamp L; a correction coefficient setting unit 11 that sets a correction coefficient KUV for correcting the UV irradiation efficiency for each lighting pattern A-E defined by the number N of the UV lamps L that are lit and the positional relation between lighting places P; and a lighting condition determination unit 12 that determines the lighting place P and the current value VC of each UV lamp L such that the effective irradiation amount AUVef of the UV light satisfies a target irradiation amount AUVtg, the effective irradiation amount AUVef being calculated using the UV irradiation amount AUVa from each UV lamp L and the correction coefficient KUV.

Description

UV irradiation device

[0001] The present invention relates to a UV irradiation device that irradiates UV (ultraviolet) rays.

[0002] Conventional UV irradiation devices are known for oxidatively decomposing TOC (organic compounds) in water, for example, by arranging multiple UV lamps in a cylinder, introducing target water, and irradiating the water with UV light from the UV lamps (see, for example, Patent Document 1). In such UV irradiation devices, it is known to control the number of UV lamps turned on or the current value passed through the UV lamps to achieve an appropriate TOC decomposition effect. Furthermore, the UV irradiation device of Patent Document 1 measures the TOC concentration of the water at the outlet side of the UV irradiation device, and when the TOC concentration exceeds a set value, the current value of the UV lamps is increased to appropriately control the UV irradiation amount.

[0003] Japanese Patent Application Laid-Open No. 2002-263643

[0004] However, in the case of the above-mentioned conventional technologies, when controlling by the number of lit UV lamps, for example, reducing the number of lit lamps is likely to cause uneven UV irradiation within the cylinder, reducing the actual UV irradiation efficiency on the water in the cylinder, which may result in the expected TOC decomposition efficiency not being achieved. Furthermore, even if the number of lit lamps is the same, if the lit locations (positions) are different, the UV irradiation efficiency on the water in the cylinder will change accordingly, and the expected TOC decomposition efficiency will also not be achieved. Furthermore, UV lamps generally have the characteristic of becoming unstable as the current value decreases. Therefore, in the case of controlling by the current value of the UV lamp described above, if the current value is reduced too much, the UV lamp operation will become unstable and the expected TOC decomposition efficiency will not be achieved.

[0005] Furthermore, in a method of controlling the current value of the UV lamp according to the measurement results of the actual TOC concentration at the outlet side of the UV irradiation device, there is a time delay after the TOC concentration exceeds the set value before it returns to the expected TOC decomposition efficiency, and during that time the TOC decomposition efficiency decreases.

[0006] The present invention has been made to solve such problems, and aims to provide a UV irradiation device that can accurately and appropriately control the UV irradiation amount of the UV lamp so that the target irradiation amount is met, while compensating for differences in UV irradiation efficiency depending on the location where the UV lamp is lit.

[0007] In order to achieve this object, the invention of claim 1 is a UV irradiation device that irradiates UV light onto a fluid, comprising: a plurality of UV lamps that are arranged in a cylinder filled with fluid and that irradiate the fluid with UV light while they are turned on; a lighting location control unit that controls the lighting locations of the plurality of UV lamps; a current value control unit that controls the current values ​​of the lit UV lamps; an irradiation efficiency parameter setting unit that sets an irradiation efficiency parameter that represents the efficiency of UV irradiation onto the fluid in the cylinder for each lighting pattern defined by the number of lit UV lamps and the positional relationship between the lighting locations; and a lighting condition determination unit that determines the lighting locations and current values ​​of the UV lamps as lighting conditions for the UV lamps so that the UV irradiation amount irradiated from the UV lamps and the effective UV irradiation amount calculated using the irradiation efficiency parameters satisfy a target irradiation amount.

[0008] In this UV irradiation device, multiple UV lamps are arranged in a cylinder filled with fluid, and the lit UV lamps irradiate the fluid with UV light. The lighting locations (number and lighting positions) of the multiple UV lamps are controlled by a lighting location control unit, and the current values ​​of the lit UV lamps are controlled by a current value control unit. As described above, the UV irradiation efficiency of the fluid in the cylinder changes depending on the number and lighting positions of the UV lamps. In contrast, according to the present invention, lighting patterns are defined based on the number of lit UV lamps and the positional relationship between the lighting locations, and an irradiation efficiency parameter representing the difference in irradiation efficiency of the fluid in the cylinder is set for each lighting pattern. The lighting locations and current values ​​of the UV lamps are then determined as UV lamp lighting conditions so that the effective UV irradiation amount calculated based on the UV irradiation amount irradiated from the UV lamps and the set irradiation efficiency parameter satisfies the target irradiation amount. By determining the UV lamp lighting conditions in this manner, the UV irradiation amount can be accurately and appropriately controlled to meet the target irradiation amount while compensating for differences in irradiation efficiency depending on the number of lit UV lamps and their lighting positions.

[0009] The invention of claim 2 is characterized in that, in the UV irradiation device described in claim 1, the lighting condition determination unit selects the lighting pattern with the greater number of lighting patterns when the effective irradiation amount satisfies the target irradiation amount and there are multiple lighting patterns with different numbers of lighting patterns.

[0010] As mentioned above, the fewer the number of UV lamps that are turned on, the more likely it is that uneven UV irradiation will occur within the cylinder, and the lower the irradiation efficiency of the fluid within the cylinder. With this configuration, when there are multiple lighting patterns that satisfy the target effective irradiation amount and have different numbers of lit lamps, the lighting pattern with the largest number of lit lamps is selected, thereby achieving higher irradiation efficiency.

[0011] The invention of claim 3 is characterized in that, in the UV irradiation device of claim 1, the irradiation efficiency parameter reflects the UV irradiation efficiency and is a correction coefficient for calculating the effective irradiation amount by multiplying the UV irradiation amount.

[0012] According to this configuration, a correction coefficient that reflects the UV irradiation efficiency is set as an irradiation efficiency parameter for each lighting pattern, and by multiplying this by the UV irradiation amount of the UV lamp, it is possible to accurately calculate the effective irradiation amount that appropriately reflects differences in irradiation efficiency.

[0013] According to a fourth aspect of the present invention, in the UV irradiation device of the first aspect, the lighting condition determining unit determines the current value so that the current value does not fall below a predetermined lower limit value.

[0014] According to this configuration, by determining the current value of the UV lamp so that it does not fall below the lower limit, it is possible to prevent the operation of the UV lamp from becoming unstable and ensure a stable amount of UV irradiation.

[0015] The invention of claim 5 is characterized in that, in the UV irradiation device of claim 1, it further comprises an operation history storage unit that stores at least one of the operating time and the number of times the UV lamp has been turned on / off since installation of the UV lamp as operation history for each UV lamp, and when there are multiple selectable UV lamps or combinations of multiple UV lamps in the determined lighting pattern, the lighting condition determination unit selects the UV lamp or combination of UV lamps with the shorter operating history as the lighting location.

[0016] In this configuration, at least one of the operating (illumination) time and the number of on / off cycles since the UV lamp was installed is stored as an operating history for each UV lamp. The longer the operating history of a UV lamp (the longer the operating time or the more on / off cycles), the shorter the remaining lifespan of the UV lamp and the greater the need for replacement or maintenance. According to the present invention, when there are multiple selectable UV lamps or combinations of UV lamps in a determined lighting pattern, the UV lamp or combination of UV lamps with the shortest operating history is selected as the lighting location. This allows multiple UV lamps to be used so that their operating histories are as even as possible, thereby reducing the frequency of UV lamp replacement and maintenance.

[0017] The invention of claim 6 is characterized in that, in the UV irradiation device of claim 3, it further comprises an operation history storage unit that stores at least one of the operating time and the number of times the UV lamp has been turned on and off since installation of the UV lamp as an operation history for each UV lamp, and the irradiation efficiency parameter setting unit sets the correction coefficient to a smaller value as the operation history becomes longer.

[0018] In this configuration, similar to the fifth aspect described above, the operation history of each UV lamp is stored. As the operation history becomes longer, the performance of the UV lamp deteriorates, and the actual UV irradiation amount decreases. According to the present invention, the longer the operation history of the UV lamp, the smaller the correction coefficient is set. This compensates for the decrease in UV irradiation amount due to the operation history, and makes it possible to appropriately calculate the effective irradiation amount.

[0019] The invention of claim 7 is characterized in that, in the UV irradiation device of claim 1, it further comprises a lighting condition presentation unit that presents the lighting conditions of the UV lamp determined by the lighting condition determination unit, and a lighting condition input unit that can manually input the presented lighting conditions.

[0020] In this configuration, the lighting conditions of the UV lamp determined by the lighting condition determination unit are presented to the lighting condition presentation unit, so that, for example, an operator in charge of managing the UV irradiation device can input the lighting conditions by manually operating the lighting condition input unit while checking this presentation.

[0021] The invention according to claim 8 is the UV irradiation device according to claim 7, further comprising a target irradiation amount input unit capable of inputting a target irradiation amount of the UV lamp.

[0022] In this configuration, the operator can manually input the predetermined target irradiation amount of the UV lamp or the target irradiation amount set appropriately depending on the situation by operating the target irradiation amount input unit.

[0023] The invention of claim 9 is a UV irradiation device according to any one of claims 1 to 8, characterized in that the UV irradiation device is used as a UV oxidation device in an ultrapure water production system that produces ultrapure water with reduced organic matter, for oxidatively decomposing organic matter in the water by irradiating the water with UV.

[0024] According to this configuration, the UV irradiation device is used as a UV oxidation device in an ultrapure water production system, which oxidatively decomposes organic matter in water by irradiating the water with UV. Therefore, this UV oxidation device can achieve the same effects as those of the UV irradiation devices of claims 1 to 8, and in particular, by precisely controlling the UV irradiation amount of the UV lamp so that it meets the target irradiation amount, it can reliably achieve the expected organic matter decomposition efficiency.

[0025] Fig. 1 is a block diagram schematically showing a UV irradiation device according to a first embodiment of the present invention and an ultrapure water production system including a UV oxidation device using the same; Fig. 2 is a diagram showing the arrangement of UV lamps in a cylinder of a UV oxidation device; Fig. 3 is a diagram showing an example of calculation of an effective UV irradiation amount; Fig. 4 is a block diagram schematically showing a UV irradiation device according to a second embodiment of the present invention and an ultrapure water production system including a UV oxidation device using the same; Fig. 5 is a block diagram schematically showing a UV irradiation device according to a third embodiment of the present invention and an ultrapure water production system including a UV oxidation device using the same;

[0026] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will now be described in detail with reference to the accompanying drawings. A UV irradiation device 1 according to a first embodiment shown in FIG.

[0027] The ultrapure water production system 2 produces ultrapure water with significantly reduced TOC (organic matter) and DO (dissolved oxygen), and includes a sub-tank 2a, a UV oxidation device 2b, an ion exchange device 2c, and a use point 2d. In the ultrapure water production system 2, primary pure water sent from the sub-tank 2a is irradiated with UV light from a UV lamp L (see FIG. 2) in the UV oxidation device 2b, whereby TOC in the primary pure water is converted into organic acids and CO ２ In the ion exchange device 2c, organic acids and CO are removed from the outflow water of the UV oxidation device 2b. ２ Most of the generated ultrapure water is sent to the use point 2d, and part of the ultrapure water is returned to the sub-tank 2a.

[0028] As shown in FIG. 1, the UV irradiation device 1 includes a correction coefficient setting unit 11, a lighting condition determination unit 12, a lighting location control unit 13, and a current value control unit 14 in addition to the UV oxidation device 2b.

[0029] 2, the UV oxidation device 2b has a cylinder C filled with water (primary pure water) W and, for example, four UV lamps L (L1 to L4) installed inside the cylinder C. The UV lamps L1 to L4 are arranged at predetermined positions spaced 90 degrees apart in the circumferential direction near the peripheral wall of the cylinder C, and each extends in the same axial direction as the cylinder C (the depth direction of the page).

[0030] The on / off of the UV lamps L1 to L4 is controlled by a lighting location control unit 13, and the current values ​​of the UV lamps L1 to L4 are controlled independently of one another by a current value control unit 14, thereby controlling the amount of UV irradiation emitted from the lit UV lamps L. The UV irradiation amount AUVa means the sum of the UV irradiation amounts from each UV lamp L (total UV irradiation amount), and is expressed as an absolute amount (unit: kWh / m ３ ) and in this control, the UV irradiation amount is expressed as a relative amount (unit: %), with the UV irradiation amount when all UV lamps L are operated at full current being 100%.

[0031] Similarly, the current value VC of each UV lamp L is expressed as a relative amount (duty rate) (%), with the current value when operated at full current being 100%. When the UV irradiation amount AUVa and the current value VC are expressed as relative amounts, the UV irradiation amount AUVa is calculated using the following formula (1): AUVa = VC · (N / 4) (1) For example, when the number of lit lamps N = 3 and the current value VC of each UV lamp L = 80%, the UV irradiation amount AUVa = 80 × (3 / 4) = 60 (%).

[0032] A correction coefficient KUV is set in the correction coefficient setting unit 11. This correction coefficient KUV reflects differences in UV irradiation efficiency depending on the number and lighting positions of the UV lamps L, and is set for each lighting pattern of the UV lamps L.

[0033] The lighting patterns are defined by the number N of lit UV lamps L and the positional relationship between the lit locations, and are classified into five patterns A to E. Specifically, as shown in Figures 2 and 3, when the number N of lit UV lamps L is 1, the lighting pattern is classified as pattern A regardless of their positions within the cylinder C. When the number N of lit UV lamps L is 2 and two lit locations are adjacent in the circumferential direction (90 degrees apart in the circumferential direction), the lighting pattern is classified as pattern B regardless of their positions within the cylinder C. When N=2 and two lit locations are opposite in the radial direction (180 degrees apart in the circumferential direction), the lighting pattern is classified as pattern C regardless of their positions within the cylinder C. When the number N=3 and all UV lamps L are lit, the lighting pattern is classified as pattern D regardless of their positions within the cylinder C. When N=4 and all UV lamps L are lit, the lighting pattern is classified as pattern E.

[0034] When multiple UV lamps L are arranged within a cylinder C, if the number N of lit lamps is small, or if the number N of lit lamps is the same but the lit locations are not well balanced, uneven UV irradiation within the cylinder C is likely to occur, reducing the actual UV irradiation efficiency on the water W within the cylinder C. For this reason, as shown in Figure 3, the correction coefficient KUV is set to a maximum value for lighting pattern E, which has the highest number N of lit lamps, and is set to decrease toward lighting pattern A (KUV = 1.0, 0.95, 0.93, 0.85, 0.7 for lighting patterns E to A).

[0035] As shown in the following equation (2), the effective UV irradiation amount AUVef effectively irradiated onto the water W in the cylinder C is calculated by multiplying the UV irradiation amount AUVa by the correction coefficient KUV set as described above for correction: AUVef = AUVa·KUV (2) Figure 3 shows an example of calculating the effective irradiation amount AUVef when the UV irradiation amount AUVa is expressed as an absolute amount. Furthermore, from equation (2) and the above equation (1), when expressed as a relative amount, the effective irradiation amount AUVef can be expressed by the following equation (3) using the current value VC of the UV lamp L and the number N of lamps turned on: AUVef = VC·(N / 4)·KUV (3)

[0036] The lighting condition determination unit 12 determines the lighting location P and current value VC of the UV lamp L so that the effective irradiation amount AUVef calculated by equation (3) matches the target irradiation amount AUVtg. This target irradiation amount AUVtg is a target value of the UV irradiation amount that is effectively irradiated onto the water W in the cylinder C, and in this example, is set to a fixed value in advance.

[0037] The current value VC is calculated for each lighting pattern using the target irradiation amount AUVtg, the number of lighting lamps N, and the correction coefficient KUV according to the following equation (4): VC = AUVtg / ((N / 4)·KUV) (4) By replacing the effective irradiation amount AUVef on the left side of the above equation (3) with the target irradiation amount AUVtg, equation (4) obtains the following equation (5), which also expresses the current value VC: AUVtg = VC·(N / 4)·KUV (5)

[0038] As described above, the effective irradiation amount AUVef is controlled to match the target irradiation amount AUVtg for each lighting pattern by calculating the current value VC of the UV lamp L. In this way, the UV irradiation amount AUVa of the UV lamp L can be accurately and appropriately controlled so as to satisfy the target irradiation amount AUVtg while compensating for differences in UV irradiation efficiency due to the number N of lit UV lamps L and their lighting positions.

[0039] The lighting condition determination unit 12 determines the lighting conditions for the UV lamps L as follows. First, when there are multiple lighting patterns in which the effective UV irradiation amount AUVef matches the target irradiation amount AUVtg and the number of lamps N that are turned on is different, the lighting pattern with the largest number of lamps N is selected. For example, as shown in Figure 2, if there are four UV lamps L and a UV irradiation amount AUVa = 75% is to be achieved, there are two possible patterns: (1) a method in which the number of lamps N is 4 and each current value VC is 75% (lighting pattern E), and (2) a method in which the number of lamps N is 3 and each current value VC is 100% (lighting pattern D). Of these, pattern (1) with the largest number of lamps N is selected.

[0040] This is because, as mentioned above, the fewer the number N of lit lamps, the more likely it is that uneven UV irradiation will occur within the cylinder C, reducing the efficiency of UV irradiation on the water W within the cylinder C. Furthermore, the fewer the number N of lit lamps, the more likely it is that the operating time and frequency of use of the UV lamps L will be uneven. From this perspective, by selecting a lighting pattern with a larger number N of lit lamps, high UV irradiation efficiency can be ensured, and the operating time of the UV lamps L can be made as equal as possible, reducing the burden of maintenance.

[0041] Second, when the current value VC calculated by equation (4) is less than a predetermined lower limit LMTL, the lighting condition determination unit 12 switches to a lighting pattern with a smaller number of lit lamps N to prevent the current value VC from falling below the lower limit LMTL. This lower limit LMTL is a value below which the operation of the UV lamp L becomes significantly unstable if the current value VC falls below this value, and is set to, for example, 70%. From this perspective, by maintaining the current value VC of the UV lamp L at or above the lower limit LMTL, it is possible to prevent the operation of the UV lamp L from becoming unstable and ensure a stable UV irradiation amount AVUa and UV irradiation efficiency.

[0042] The lighting condition determination unit 12 determines the lighting conditions (lighting pattern, lighting location P, and current value VC) of the UV lamp L as described above, and outputs a signal representing the lighting conditions to the lighting location control unit 13 and the current value control unit 14.

[0043] The lighting area control unit 13 has a switch (not shown) for individually turning on / off the UV lamps L, and controls the lighting area P by controlling the on / off of each UV lamp L according to the lighting area P input from the lighting condition determination unit 12.

[0044] The current value control unit 14 has an inverter circuit (not shown) that variably controls the current passed through the UV lamps L, and by controlling the inverter circuit in accordance with the current value VC input from the lighting condition determination unit 12, the current value of each UV lamp L that is turned on is controlled to the determined current value VC, thereby controlling the UV irradiation amount AUVa.

[0045] As described above, according to the UV irradiation device 1 of this embodiment, the lighting location P of the UV lamp L and the current value VC are determined so that the effective irradiation amount AUVef calculated using the UV irradiation amount AUVa irradiated from the UV lamp L and the correction coefficient KUV matches the target irradiation amount AUVtg. This makes it possible to accurately and appropriately control the UV irradiation amount AUVa so that the target irradiation amount AUVtg is achieved while compensating for differences in UV irradiation efficiency depending on the lighting location P of the UV lamp L.

[0046] Second Embodiment Next, a UV irradiation device 21 according to a second embodiment will be described with reference to Figure 4. As is clear from a comparison with Figure 1, this UV irradiation device 21, like the UV irradiation device 1 of the first embodiment, is used in the UV oxidation device 2b of the ultrapure water production system 2, and differs mainly in that an operation history storage unit 22 is added to the UV irradiation device 1. For this reason, in Figure 4, components that are the same as or equivalent to those of the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0047] The operation history storage unit 22 stores the operation time TL and the number of on / off times NS of the UV lamp L as parameters representing the operation history for each UV lamp L. The operation time TL is the measured and accumulated operation time (lighting time) of each UV lamp L since installation, and is stored as needed in the operation history storage unit 22. The number of on / off times NS is the count of the number of on / off times (number of times of operation) of each UV lamp L since installation, and is stored as needed in the operation history storage unit 22.

[0048] In this embodiment, the operating time TL and the on / off count NS are used to set the correction coefficient KUV and select the lighting location P of the UV lamp L. First, the correction coefficient setting unit 11 sets the correction coefficient KUV according to the operating time TL and the on / off count NS read from the operating history storage unit 22. Specifically, the longer the operating time TL and the greater the on / off count NS, i.e., the longer the operating history, the smaller the correction coefficient KUV is set to.

[0049] This takes into consideration that as the operating history becomes longer, the performance of the UV lamp L deteriorates and the actual UV irradiation amount AUVa decreases. Based on this viewpoint, by setting the correction coefficient KUV as described above in accordance with the operating history of the UV lamp L, it is possible to compensate for the decrease in the UV irradiation amount AUVa in accordance with the operating history and appropriately evaluate the effective irradiation amount AUVef.

[0050] Furthermore, when there are multiple selectable UV lamps L or combinations thereof in the determined lighting pattern, the lighting condition determination unit 12 selects the UV lamp L or combinations thereof with the shorter operating history (shorter operating time TL and fewer on / off counts NS) as the lighting location P. This is because the longer the operating history, the shorter the remaining life of the UV lamp L and the greater the need for replacement or maintenance. Based on this perspective, by selecting the lighting location P as described above according to the operating history of the UV lamp L, the multiple UV lamps L can be used so that their operating histories are as uniform as possible, thereby reducing the frequency of replacement and maintenance of the UV lamps L.

[0051] Other configurations of this embodiment are the same as those of Embodiment 1. Therefore, according to this embodiment, in addition to the above-mentioned effects, the same effects as those of Embodiment 1 can be obtained.

[0052] [Third Embodiment] Next, a UV irradiation device 41 according to a third embodiment will be described with reference to Figure 5. As is clear from a comparison with Figure 4, this UV irradiation device 41, like the UV irradiation devices 1 and 21 of the first and second embodiments, is used in the UV oxidation device 2b of the ultrapure water production system 2, and differs from the UV irradiation device 21 of the second embodiment in that it adds a lighting condition presentation unit 42, a lighting condition input unit 43 for manual input by an operator OP, and a target irradiation dose input unit 44. For this reason, in Figure 5, components that are the same as or equivalent to those of the second embodiment are designated by the same reference numerals, and descriptions thereof will be omitted.

[0053] The lighting condition presentation unit 42 displays the lighting conditions (lighting pattern, lighting location P, and current value VC) of the UV lamps L determined by the lighting condition determination unit 12 on a touch panel or the like (not shown), and presents them to an operator OP who manages the UV irradiation device 41. The lighting condition input unit 43 has an operation panel (not shown), and is connected to the lighting location control unit 13 and the current value control unit 14.

[0054] With this configuration, the operator OP can input the lighting location P and the current value VC to the lighting location control unit 13 and the current value control unit 14 by manually operating the operation panel of the lighting condition input unit 43 while checking the lighting conditions of the UV lamp L presented by the lighting condition presentation unit 42. In this case, the lighting conditions may be input as presented by the lighting condition presentation unit 42, or the lighting conditions may be input with some changes based on the presentation.

[0055] The target irradiation amount input unit 44 has an operation panel (not shown) and is connected to the lighting condition determination unit 12. With this configuration, the operator OP can manually operate the operation panel of the target irradiation amount input unit 44 to input the target irradiation amount AUVtg of the UV lamp L to the lighting condition determination unit 12. In this case, the target irradiation amount AUVtg may be a predetermined constant value or may be set appropriately depending on the situation.

[0056] Other configurations of this embodiment are the same as those of Embodiment 2. Therefore, according to this embodiment, in addition to the above-mentioned effects, the same effects as those of Embodiment 2 can be obtained.

[0057] The present invention is not limited to the described embodiment and can be implemented in various forms. For example, in the embodiment, four UV lamps L are arranged at 90-degree intervals in the circumferential direction within a cylinder C having a circular cross section, and the lighting patterns are classified into five patterns taking into account UV irradiation efficiency. This configuration is merely exemplary, and the present invention can be applied to cases where the cross-sectional shape of the cylinder C or the number and arrangement of the UV lamps L are different. In such cases, the lighting patterns are appropriately set to reflect actual differences in UV irradiation efficiency. Furthermore, if the evaluation of UV irradiation efficiency becomes complicated due to the number and arrangement of the UV lamps L, the UV irradiation efficiency may be estimated using a simulation based on flow analysis or a predictive model based on machine learning, and the lighting patterns may be set based on the results.

[0058] In addition, in the second embodiment, both the operating time TL and the number of on / off times NS are used as the operating history of the UV lamp L, but it is also possible to use only one of them, or to use other appropriate parameters that represent the operating history.

[0059] Furthermore, in the third embodiment, the target irradiation amount AUVtg is set in advance and input manually. However, the present invention is not limited to this. For example, the water quality in the cylinder C may be detected while the UV lamp L is operating, and the target irradiation amount AUVtg may be automatically changed in accordance with the detection result and input to the lighting condition determination unit 12.

[0060] The lighting condition determination unit 12 may be constructed on-premise or may be set on a server. The lighting condition presentation unit 42 in the third embodiment has been described as displaying the lighting conditions on a touch panel or the like, but is not limited thereto and may be, for example, a unit that displays the lighting conditions on a browser in a web service or notifies the user via an email service.

[0061] In the embodiments, the UV irradiation device is used as a UV oxidation device in an ultrapure water production system, irradiating primary pure water with UV to oxidatively decompose TOC. The present invention is not limited to this, and can be applied to UV irradiation devices in ultrapure water subsystems, UV irradiation devices for disinfection in water purification plants, and a wide range of UV irradiation devices that require precise control of the amount of UV irradiation from a UV lamp to a fluid (liquid or gas). Furthermore, the configurations specifically shown in the embodiments are merely examples, and can be modified as appropriate within the spirit and scope of the present invention.

[0062] This application claims priority based on Japanese Patent Application No. 2024-070069, filed on April 23, 2024, and incorporates by reference all of the contents of that Japanese application.

[0063] REFERENCE SIGNS LIST 1 UV irradiation device according to first embodiment 2 Ultrapure water production device 2a UV oxidation device 11 Correction coefficient setting unit (irradiation efficiency parameter setting unit) 12 Lighting condition determination unit 13 Lighting location control unit 14 Current value control unit 21 UV irradiation device according to second embodiment 22 Operation history storage unit 41 UV irradiation device according to third embodiment 42 Lighting condition presentation unit 43 Lighting condition input unit 44 Target irradiation amount input unit UV Ultraviolet light C Cylinder W Primary pure water (fluid) L UV lamp P Lighting location of UV lamp VC Current value of UV lamp N Number of lit UV lamps AUVa UV irradiation amount of UV lamp KUV Correction coefficient (irradiation efficiency parameter) AUVef Effective UV irradiation amount AUVtg Target UV irradiation amount LMTL Lower limit of current value TL UV lamp operating time (operating history) NS UV lamp on / off count (operating history) TOC Organic matter

Claims

1. A UV irradiation device that irradiates UV light onto a fluid, comprising: a plurality of UV lamps that are placed inside a cylinder filled with the fluid and that irradiate the fluid with UV light while they are turned on; a lighting location control unit that controls the lighting locations of the plurality of UV lamps; a current value control unit that controls the current values ​​of the UV lamps that are turned on; an irradiation efficiency parameter setting unit that sets irradiation efficiency parameters that represent the efficiency of UV irradiation onto the fluid inside the cylinder for each lighting pattern defined by the number of UV lamps that are turned on and the positional relationship between the lighting locations; and a lighting condition determination unit that determines the lighting locations and current values ​​of the UV lamps as lighting conditions for the UV lamps so that the UV irradiation amount irradiated from the UV lamps and the effective UV irradiation amount calculated based on the irradiation efficiency parameters satisfy a target irradiation amount.

2. The UV irradiation device according to claim 1, characterized in that when there are a plurality of lighting patterns in which the effective irradiation amount satisfies the target irradiation amount and the number of lighting beams differs, the lighting condition determination unit selects the lighting pattern in which the number of lighting beams is greater.

3. The UV irradiation device according to claim 1, wherein the irradiation efficiency parameter reflects the UV irradiation efficiency and is a correction coefficient for calculating the effective irradiation amount by multiplying the UV irradiation amount by the parameter.

4. The UV irradiation device according to claim 1, wherein the lighting condition determining unit determines the current value so that it does not fall below a predetermined lower limit value.

5. The UV irradiation device of claim 1, further comprising an operation history storage unit that stores at least one of the operating time and the number of times the UV lamp has been turned on / off since installation of the UV lamp as an operation history for each UV lamp, and wherein when the determined lighting pattern includes a plurality of selectable UV lamps or a combination of a plurality of UV lamps, the lighting condition determination unit selects the UV lamp or combination of UV lamps with the shortest operating history as the lighting location.

6. The UV irradiation device according to claim 3, further comprising an operation history storage unit that stores, for each UV lamp, at least one of the operating time and the number of times the UV lamp has been turned on and off since installation as an operation history, and wherein the irradiation efficiency parameter setting unit sets the correction coefficient to a smaller value as the operating history becomes longer.

7. A UV irradiation device as described in claim 1, further comprising a lighting condition presentation unit that presents the lighting conditions of the UV lamp determined by the lighting condition determination unit, and a lighting condition input unit that allows the presented lighting conditions to be input by manual operation.

8. The UV irradiation device according to claim 7, further comprising a target irradiation amount input unit capable of inputting a target irradiation amount of the UV lamp.

9. A UV irradiation device according to any one of claims 1 to 8, characterized in that the UV irradiation device is used as a UV oxidation device in an ultrapure water production system that produces ultrapure water with reduced organic matter, for oxidatively decomposing organic matter in water by irradiating the water with UV light.

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