Water quality analysis device
The water quality analysis device addresses contamination issues by adjusting ultraviolet light intensity and flow rate to prevent biofilm formation and maintain optical window clarity, ensuring accurate and reliable analysis results.
Patent Information
- Application Number
- JP2023094698
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2023-06-08
- Publication Date
- 2024-12-19
AI Technical Summary
In water quality analyzers, the internal container in contact with liquid is prone to contamination, which can lead to errors in analysis due to the formation of biofilms and stains on optical windows.
A water quality analysis device that includes a dirt calculation control section to adjust ultraviolet light intensity based on a dirt index, intermittently irradiates ultraviolet light to prevent biofilm formation, and controls the flow rate of water to remove dirt, using a configuration with scattered and ultraviolet light windows and a light shielding part to minimize contamination.
Effectively prevents contamination of the liquid-contacted container, maintaining accurate analysis by reducing biofilm formation and maintaining optical window clarity, thus extending the life of the device and ensuring reliable measurement results.
Smart Images
Figure 2024176264000001_ABST
Abstract
Description
[Technical field]
[0001] The present invention relates to a water quality analyzer. [Background technology]
[0002] Conventionally, in a water quality analyzer for analyzing the quality of a sample water, a cleaning method using ultrasonic waves, a gas-liquid jet nozzle, or a wiper is known (see, for example, Patent Documents 1 to 3). Also, a measuring device equipped with two types of light sources is known (see, for example, Patent Document 4). [Prior art document] [Patent documents] [Patent Document 1] Special Publication No. 2015-500461 [Patent Document 2] JP 2008-2956 A [Patent Document 3] Japanese Patent Application Laid-Open No. 9-54076 [Patent Document 4] JP 2022-59278 A Summary of the Invention [Problem to be solved by the invention]
[0003] In a water quality analyzer, it is preferable to prevent the inside of a liquid-contacting container from becoming dirty. [Means for solving the problem]
[0004] In an embodiment of the present invention, there is provided a water quality analysis device for analyzing water to be measured. The water quality analysis device may include a liquid-contacting container having an internal space through which the water to be measured flows. Any of the above water quality analysis devices may include a measurement light irradiating optical system that irradiates measurement light into the internal space. Any of the above water quality analysis devices may include an ultraviolet light irradiating optical system that irradiates ultraviolet light into the internal space. Any of the above water quality analysis devices may include a detection optical system that analyzes the water to be measured based on the measured light from the liquid-contacting container. Any of the above water quality analysis devices may include a contamination calculation control unit that calculates a contamination index that indicates the degree of contamination of the liquid-contacting container based on an analysis result of the detection optical system. In any of the above water quality analysis devices, the contamination calculation control unit may control the intensity of the ultraviolet light depending on the result of the contamination index.
[0005] In any of the water quality analyzing devices described above, the contamination calculation control unit may increase the intensity of the ultraviolet light when the contamination index value becomes greater than a predetermined value.
[0006] In any of the water quality analyzers described above, the predetermined value may be determined according to the type of the measurement target water.
[0007] In any of the water quality analysis devices described above, the ultraviolet light irradiation optical system may intermittently irradiate the ultraviolet light while the water quality analysis device is analyzing the measurement target water.
[0008] In any of the water quality analyzing devices described above, the ultraviolet light may have a greater degree of diffusion than the measurement light.
[0009] In any of the above water quality analysis devices, the liquid-contacting container may have a scattered light window through which the light to be measured passes.In any of the above water quality analysis devices, the liquid-contacting container may have an ultraviolet light window through which the ultraviolet light passes.In any of the above water quality analysis devices, the ultraviolet light window may be disposed in a position facing the scattered light window with the internal space therebetween.
[0010] Any of the water quality analysis devices described above may further include a flow rate control unit that controls the flow rate of the measurement target water to remove the contaminants.
[0011] In any of the above-mentioned water quality analysis devices, the pollution calculation control unit calculates the pollution index, and if the pollution index is greater than a predetermined value, the pollution calculation control unit increases the light intensity and duty ratio of the ultraviolet light, and the flow rate control unit repeatedly performs an operation of increasing the flow rate of the water to be measured.
[0012] In any of the above water quality analysis devices, the liquid-contacting container may have a scattered light window through which the light to be measured passes. In any of the above water quality analysis devices, the liquid-contacting container may have an ultraviolet light window through which the ultraviolet light passes. In any of the above water quality analysis devices, the liquid-contacting container may have a light-shielding section provided in the internal space and guiding the ultraviolet light from the ultraviolet light window to the scattered light window. In any of the above water quality analysis devices, an inner wall of the light-shielding section may reflect the ultraviolet light.
[0013] The above summary of the invention does not list all of the necessary features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]
[0014] [Figure 1] FIG. 1 is a diagram showing a water quality analysis device 100 according to an embodiment of the present invention. [Diagram 2] 2 is a diagram showing an example of the configuration of a liquid contact container 10 and an optical system. FIG. [Diagram 3] 13 is a diagram for explaining the effect of irradiation with ultraviolet light 52. FIG. [Figure 4] FIG. 13 is a diagram showing an example of a flowchart for controlling ultraviolet light 52 using a contamination index and for controlling the flow rate of water to be measured. [Diagram 5] 4 is a diagram showing an example of the arrangement of a light shielding portion 70 provided in the liquid contact container 10. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0015] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. In this specification, the same parts in each figure are given the same reference numerals, and the description may be omitted. In addition, some configurations may not be illustrated for convenience of explanation.
[0016] In this specification, technical matters may be explained using an orthogonal coordinate system of X, Y, and Z axes. The orthogonal coordinate system merely specifies the relative positions of components, and does not limit a specific direction. For example, the Z-axis direction does not limit the height direction relative to the ground. In this specification, when something is referred to as "vertical" or "parallel," it may include a deviation of, for example, about 5°.
[0017] FIG. 1 is a diagram showing a water quality analysis device 100 in an embodiment of the present invention. The water quality analysis device 100 analyzes the water to be measured. The water quality analysis device 100 measures the turbidity of the water to be measured and the concentration of specific components contained in the water to be measured. The water to be measured is seawater, for example. Since seawater contains a relatively large number of microorganisms, this embodiment will be described using seawater as the water to be measured, but the water to be measured may be freshwater, wastewater, or other liquid.
[0018] The water quality analyzer 100 comprises a liquid-contacting container 10, a contamination calculation control unit 14, a measurement light irradiating optical system 20, a scattered light detecting optical system 30 (see FIG. 2), a transmitted light detecting optical system 40, an ultraviolet light irradiating optical system 50, a flow rate control unit 60, and a liquid flow pipe 62. The flow rate control unit 60 controls the flow rate of the measurement target water to flow into the liquid-contacting container 10. The flow rate control unit 60 may control the flow rate by controlling a pump, or may control the flow rate by controlling a valve. The measurement target water flows into the liquid-contacting container 10 through the liquid flow pipe 62.
[0019] The water to be measured is analyzed in the liquid contact container 10. The liquid contact container 10 has an optical window that transmits light between the inside and outside of the liquid contact container 10. Although FIG. 1 shows a transmitted light window 44 and an ultraviolet light window 54, the liquid contact container 10 may have other optical windows. The liquid contact container 10 and its surrounding optical system will be described with reference to FIG. 2. The water quality analyzer 100 is an optical analyzer that irradiates the water to be measured with light and analyzes the water to be measured from the scattered light or the like. The water quality analyzer 100 in this example is a continuous type in which the water to be measured passes through the liquid contact container 10, but is not limited to this. The water quality analyzer 100 may perform measurements in a state in which the water to be measured remains in the liquid contact container 10 without passing through it. In FIG. 1 and the following figures, the direction in which the water to be measured flows through the inside of the liquid contact container 10 is the positive Z-axis direction, and the plane perpendicular to the Z-axis direction is the XY plane.
[0020] The dirt calculation control unit 14 is connected to the scattered light detection optical system 30 via a scattered light detection signal line 36, to the transmitted light detection optical system 40 via a transmitted light detection signal line 46, to the ultraviolet light irradiation optical system 50 via an ultraviolet light detection signal line 56, and to the flow velocity control unit 60 via a flow velocity control signal line 66. The dirt calculation control unit 14 may calculate the dirt of the liquid contact container 10 based on the analysis results of one or both of the scattered light detection optical system 30 and the transmitted light detection optical system 40 as described below. The dirt calculation control unit 14 may control the ultraviolet light irradiation optical system 50 based on the result of the calculation to change the intensity of the ultraviolet light. The dirt calculation control unit 14 may control the flow velocity control unit 60 based on the result of the calculation to change the flow velocity of the measurement target water and remove the dirt from the liquid contact container 10.
[0021] Fig. 2 is a diagram showing an example of the configuration of the liquid-contacting container 10 and the optical system. The liquid-contacting container 10 in Fig. 2 shows a cross section in the XY plane. The liquid-contacting container 10 has an internal space 12 through which the water to be measured flows. In Fig. 2, the water to be measured flows toward the front of the page (positive direction of the Z axis).
[0022] The liquid contact vessel 10 has a measurement light window 24, a scattered light window 34, a transmitted light window 44, and an ultraviolet light window 54. The measurement light window 24, the scattered light window 34, the transmitted light window 44, and the ultraviolet light window 54 are optical windows provided to allow light to pass between the internal space 12 of the liquid contact vessel 10 and the outside. In this specification, the measurement light window 24, the scattered light window 34, the transmitted light window 44, and the ultraviolet light window 54 may be collectively referred to as optical windows. In FIG. 2, the optical windows are provided in the internal space 12, but they may be provided outside the liquid contact vessel 10 or embedded in the wall of the liquid contact vessel 10.
[0023] The measurement light irradiating optical system 20 irradiates the internal space 12 with measurement light 22. The measurement light irradiating optical system 20 may irradiate the measurement light 22 from outside the liquid-contacting container 10 toward the measurement target water in the internal space 12. The measurement light irradiating optical system 20 includes a lamp or an LED as a light source. The measurement light 22 may be white light or monochromatic light. The measurement light irradiating optical system 20 is provided at a position where the measurement light 22 is irradiated from the measurement light window 24 toward the internal space 12 of the liquid-contacting container 10.
[0024] When the measurement water is irradiated with the measurement light 22, part of the measurement light 22 is scattered or absorbed by the components and suspended matter contained in the measurement water, and the other part is transmitted without being scattered or absorbed. When the measurement light 22 with a short wavelength is irradiated onto the measurement water containing a specific chemical substance, fluorescence specific to the chemical substance is generated.
[0025] The scattered light detection optical system 30 detects scattered light 32 from the target water. The scattered light 32 may be scattered light, fluorescent light, or ultraviolet light, which will be described later. The scattered light detection optical system 30 is provided at a position where it can detect the scattered light 32 emitted from the scattered light window 34.
[0026] The transmitted light detection optical system 40 detects transmitted light 42 from the water to be measured. The transmitted light 42 may include fluorescence, and may also include ultraviolet light, which will be described later. The transmitted light detection optical system 40 is provided at a position to detect the transmitted light 42 emerging from a transmitted light window 44. The scattered light detection optical system 30 and the transmitted light detection optical system 40 are equipped with light receiving elements such as photodiodes and photomultiplier tubes, and detect the intensities of the scattered light 32 and the transmitted light 42.
[0027] When the turbidity of the water to be measured increases, the intensity of the scattered light 32 increases. When the turbidity of the water to be measured increases, the amount of light absorption, which is the intensity of the measurement light 22 minus the intensity of the transmitted light 42, also increases. When the concentration of the substance to be measured increases, the intensity of the scattered light 32 and the fluorescence increases, and the amount of light absorption also increases. Therefore, by detecting the intensity of at least one of the scattered light 32, the fluorescence, and the transmitted light 42, it is possible to calculate the turbidity of the water to be measured and the concentration of the substance to be measured. In this specification, the scattered light 32 and the transmitted light 42 may be collectively referred to as the measured light 48. Also, the scattered light detection optical system 30 and the transmitted light detection optical system 40 may be collectively referred to as the detection optical system 58. The scattered light detection optical system 30 and the transmitted light detection optical system 40 may be connected by a signal line (not shown), and may communicate the intensity values detected by each of them. The scattered light detection optical system 30 and the transmitted light detection optical system 40 may include a calculation unit.
[0028] The detection optical system 58 may analyze the target water based on the measured light 48 from the liquid-contacting container 10. The detection optical system 58 may calculate the above-mentioned turbidity or concentration. The detection optical system 58 may include at least one of the scattered light detection optical system 30 and the transmitted light detection optical system 40. As an example, the detection optical system 58 may include only the scattered light detection optical system 30, and calculate the turbidity of the target water based on the intensity of the detected scattered light 32.
[0029] When microorganisms are present in the water to be measured, the microorganisms may adhere to the optical window of the liquid-contacting container 10 and form stains. The above-mentioned stains are, for example, biofilms. A biofilm is an aggregate of bacteria that adheres to and grows on the surface of a material that comes into contact with a solution in which the microorganisms exist, due to extracellular polymers (EPS) produced by cells. In this specification, stains mainly refer to biofilms. When stains form on the optical window, they block the light that passes through the optical window, making the analysis results more susceptible to errors.
[0030] The ultraviolet light irradiation optical system 50 irradiates the internal space 12 with ultraviolet light 52. The ultraviolet light irradiation optical system 50 may irradiate the ultraviolet light 52 from the outside of the liquid-contacting container 10 toward an optical window in the internal space 12. Since ultraviolet light has a sterilizing effect, it can sterilize microorganisms present in the measurement target water and prevent the formation of dirt. The ultraviolet light irradiation optical system 50 is provided at a position where it irradiates the ultraviolet light 52 from the ultraviolet light window 54 toward the internal space 12 of the liquid-contacting container 10.
[0031] The ultraviolet light irradiation optical system 50 includes a lamp or an LED as a light source. The wavelength of the ultraviolet light 52 may be UV-C (up to 280 nm). As an example, the intensity of the ultraviolet light 52 is 0.2 mW / cm at the center at full power. 2 , the radiation intensity in the peripheral area is 0.12 mW / cm 2 The central portion is a portion of the light source exit surface that intersects with the optical axis, and the peripheral portion is a portion of the light source exit surface that is furthest from the optical axis.
[0032] The ultraviolet light 52 may be diffused light. The ultraviolet light 52 may have a greater degree of diffusion than the measurement light 22. The degree of diffusion may be the degree to which light spreads while it travels a predetermined distance. This makes it easier for the ultraviolet light 52 irradiated into the internal space 12 to reach multiple optical windows. The ultraviolet light irradiation optical system 50 may irradiate the ultraviolet light 52 into the internal space 12 so that the ultraviolet light 52 reaches all optical windows provided in the liquid contact container 10.
[0033] The ultraviolet light window 54 may be disposed in a position facing the scattered light window 34 across the internal space 12. In FIG. 2, the ultraviolet light window 54 is disposed in a position facing the scattered light window 34 in the Y-axis direction. The optical axis of the ultraviolet light 52 may be parallel to the Y-axis direction. As described above, the intensity of the ultraviolet light 52 is stronger in the center than in the peripheral portion. Therefore, by disposing the ultraviolet light window 54 and the scattered light window 34 opposite each other, the amount of ultraviolet light irradiated onto the scattered light window 34 can be increased. This makes it possible to prevent the scattered light window 34, through which the scattered light 32 that is directly related to the measured value passes, from becoming dirty.
[0034] The ultraviolet light irradiation optical system 50 may intermittently irradiate the ultraviolet light 52 while the water quality analysis device 100 is analyzing the measurement target water. As an example, the measurement light irradiation optical system 20 and the ultraviolet light irradiation optical system 50 alternately irradiate the measurement light 22 and the ultraviolet light 52 while the water quality analysis device 100 is analyzing the measurement target water. In this example, while the measurement target water is being analyzed refers to a period during which the measurement light 22 is intermittently irradiated to analyze the same measurement target water. The period during which the measurement target water is being analyzed does not need to include a period for cleaning or calibrating the water quality analysis device 100. Specifically, the measurement light irradiation optical system 20 may irradiate the measurement light 22 for half of the unit time, and the ultraviolet light irradiation optical system 50 may irradiate the ultraviolet light 52 for the other time. In other words, half of the unit time may be a time for irradiating the measurement light 22, and the other time may be a time for irradiating the ultraviolet light 52. The above unit time is repeated while the measurement target water is being analyzed. The unit time may be one second, one minute, or twice the time required to receive the amount of measured light 48 required for analysis. This makes it possible to extend the life of the light source and to suppress the influence of ultraviolet light 52 on the analysis of the target water.
[0035] The contamination calculation control unit 14 calculates a contamination index that indicates the degree of contamination of the liquid contact container 10 based on the analysis result of the detection optical system 58. The contamination index is expressed by the following formula, for example. Soil index=1−(intensity of scattered light 32+intensity of transmitted light 42) / (intensity of initial scattered light+intensity of initial transmitted light) The contamination index ranges from 0 to 1. A high contamination index value means that the liquid contact vessel 10 is contaminated. The contamination index may be calculated using only either the scattered light 32 or the transmitted light 42.
[0036] The dirt calculation control unit 14 may control the intensity of the ultraviolet light 52 according to the result of the dirt index. The dirt calculation control unit 14 may change the intensity of the ultraviolet light 52 by controlling the ultraviolet light irradiation optical system 50. The dirt calculation control unit 14 may increase the intensity of the ultraviolet light 52 when the dirt index value becomes larger than a predetermined value. The predetermined value is 0.2, for example. This makes it possible to further suppress the formation of dirt.
[0037] During the biofilm formation stage, bacteria attached to the surface of a material produce EPS, which forms microcolonies and clumps, promoting the formation of the biofilm. In other words, the production of EPS causes the biofilm to grow rapidly. UV light 52 inhibits the production of the EPS, and therefore can suppress the formation of the biofilm.
[0038] Since the grown biofilm strongly adheres to the surface of the material and is difficult to remove, it is desirable to stop the biofilm formation stage before the EPS production stage by adjusting the intensity of the ultraviolet light 52.
[0039] The stage where the biofilm grows rapidly due to EPS production appears as a sudden increase in the contamination index over time. Therefore, it is preferable to experimentally obtain in advance the contamination index value at which the contamination index starts to increase rapidly (called the critical contamination index value). The contamination calculation control unit 14 may use the critical contamination index value as the predetermined value, or may use a value 0.8 times the critical contamination index value, or may use a value 0.5 times the critical contamination index value.
[0040] The critical contamination index value also differs depending on the type of the measurement target water. The predetermined value may be determined according to the type of the measurement target water. This makes it possible to effectively prevent the formation of contamination for each measurement target water.
[0041] By preventing the formation of a biofilm by irradiating with ultraviolet light, dirt does not adhere strongly to the optical window. Therefore, most of the dirt is removed by flowing the measurement target water through the internal space 12. The flow rate control unit 60 may remove the dirt by controlling the flow rate of the measurement target water. Since the formation of a biofilm is prevented by irradiating with ultraviolet light, dirt can be removed by a light cleaning method such as controlling the flow rate of the measurement target water. In this specification, control of the flow rate of the measurement target water is used as a method for removing dirt, but other cleaning methods may also be used.
[0042] FIG. 3 is a diagram for explaining the effect of irradiation with ultraviolet light 52. The inventors conducted a comparative experiment to verify the effect of ultraviolet light 52 in preventing fouling. In the experiment, the state and transmittance of the optical window were measured 20 days after the measurement water was passed through. The measurement water was seawater. The upper row of FIG. 3 shows examples, and the lower row shows comparative examples. The second column from the left in FIG. 3 shows whether or not ultraviolet light 52 was irradiated. In the examples, the above-mentioned ultraviolet light 52 was irradiated continuously, and in the comparative examples, ultraviolet light 52 was not irradiated.
[0043] The third column from the left in Fig. 3 shows stains on the optical window. The diagrams of the optical window shown in the third column are visual images. In the example, small stains (black ovals in the figure) were partially formed, but most of the stains were not formed. On the other hand, in the comparative example, a thin stain (hatched in the figure) was formed on one surface of the optical window, and a dark stain (black ovals in the figure) was formed within it.
[0044] The fourth column from the left in Fig. 3 shows the light transmittance. The standard for the transmittance is the initial transmittance before the measurement water is passed through, which is set to 100%. In the working example, a transmittance of 98% was measured, while in the comparative example, a transmittance of 74%, which is lower than that of the working example, was measured. In other words, it was confirmed that contamination can be significantly prevented by irradiating with ultraviolet light 52.
[0045] 4 is a diagram showing an example of a flowchart for controlling the ultraviolet light 52 and the flow rate of the measurement target water using the contamination index. In step S100, the contamination calculation control unit 14 calculates the contamination index described above. In step S102, the contamination calculation control unit 14 determines whether the contamination index is greater than a predetermined value. In this example, the predetermined value is 0.2. If the contamination index value is not greater than the predetermined value, subsequent processing does not need to be performed, and the contamination index may be calculated again.
[0046] If the dirt index is greater than a predetermined value, in step S104, the dirt calculation control unit 14 increases the light amount and duty ratio of the ultraviolet light 52. Increasing the light amount of the ultraviolet light 52 may mean increasing the output of the ultraviolet light irradiation optical system 50, or may mean increasing the drive current. In FIG. 4, the light amount and duty ratio of the ultraviolet light 52 are increased by 10%.
[0047] In step S106, the contamination calculation control unit 14 determines whether the amount of light and the duty ratio of the ultraviolet light 52 have reached 100%. The amount of the ultraviolet light 52 being 100% may mean that the output of the ultraviolet light irradiation optical system 50 is at its maximum.
[0048] When both the light amount and the duty ratio of the ultraviolet light 52 are 100%, in step S108, the contamination calculation control unit 14 determines whether the contamination index value is greater than a predetermined value. The predetermined value in step S108 may be greater than the predetermined value in step S102. In this example, the predetermined value is 0.7.
[0049] In step S108, if the value of the contamination index is greater than a predetermined value, the contamination calculation control unit 14 determines that maintenance or part replacement of the water quality analysis device 100 is necessary. In this case, the contamination calculation control unit 14 may notify the outside that maintenance or part replacement is necessary. In step S108, if the value of the contamination index is less than a predetermined value, the contamination calculation control unit 14 may not need to perform any particular process. In this case, the contamination calculation control unit 14 may continue to periodically check whether the value of the contamination index is greater than a predetermined value.
[0050] If both the light intensity and duty ratio of the ultraviolet light 52 are not 100% in step S106, the flow rate control unit 60 increases the flow rate of the measurement target water in step S110. As an example, the flow rate is increased once an hour for several tens of seconds, and the increased flow rate is 200% to 300% of the normal flow rate. The contamination calculation control unit 14 may send a command to the flow rate control unit 60 to increase the flow rate of the measurement target water.
[0051] In step S112, the contamination calculation control unit 14 maintains the delay time, the light intensity and duty ratio of the ultraviolet light 52, and the flow rate of the water to be measured increased. The delay time is the period until the contamination reduction effect appears. In this example, the delay time is set to a period of 1 to 3 days.
[0052] In step S114, the contamination calculation control unit 14 judges whether the delay time has elapsed. If the delay time has not elapsed, the contamination calculation control unit 14 continues to maintain the increased light intensity and duty ratio of the ultraviolet light 52 and the increased flow rate of the measurement target water. If the delay time has elapsed, the operation of step S100 is performed again. The water quality analysis device 100 may repeat the operation of FIG. 4.
[0053] 5 is a diagram showing an example of the arrangement of a light-shielding part 70 provided in the liquid-contacting container 10. The liquid-contacting container 10 of this example has a light-shielding part 70 provided in the internal space 12. When ultraviolet light 52 is irradiated into the internal space 12, the liquid-contacting container 10 may be deteriorated by the ultraviolet light 52. By providing the light-shielding part 70, the ultraviolet light 52 irradiated onto the inner wall of the liquid-contacting container 10 can be reduced, and deterioration of the liquid-contacting container 10 can be prevented. Furthermore, by providing the light-shielding part 70, the effect of stray light on measurement can be reduced.
[0054] The light-shielding part 70 may be provided so as to block at least a part of a straight line connecting the ultraviolet light window 54 and the inner wall of the liquid-contacting container 10. The light-shielding part 70 may be provided so as to block the entire straight line connecting the ultraviolet light window 54 and the inner wall of the liquid-contacting container 10. The light-shielding part 70 guides the ultraviolet light 52 from the ultraviolet light window 54 to the scattered light window 34. The light-shielding part 70 may guide the ultraviolet light 52 from the ultraviolet light window 54 to the measurement light window 24 or to the transmitted light window 44. The inner wall of the light-shielding part 70 may reflect the ultraviolet light 52. The inner wall of the light-shielding part 70 may be a wall surface of the light-shielding part 70 that faces the light path through which the measurement light 22, the scattered light 32, the transmitted light 42, or the ultraviolet light 52 passes, a wall surface that does not face the inner wall of the liquid-contacting container 10, or a wall surface that faces other parts of the light-shielding part 70. This allows the ultraviolet light 52 to be directed to all of the optical windows.
[0055] The outer wall of the light-shielding part 70 may absorb the ultraviolet light 52. The outer wall of the light-shielding part 70 may be a wall surface of the light-shielding part 70 that does not face the optical path through which the measurement light 22, the scattered light 32, the transmitted light 42, or the ultraviolet light 52 passes, may be a wall surface that faces the inner wall of the liquid-contacting container 10, or may be a wall surface that does not face other parts of the light-shielding part 70. This makes it possible to further reduce the ultraviolet light 52 irradiated to the inner wall of the liquid-contacting container 10. The inner wall of the light-shielding part 70 may be coated with a material that has a high reflectance to the ultraviolet light 52. The outer wall of the light-shielding part 70 may be coated with a material that has a low reflectance to the ultraviolet light 52. The inner wall of the light-shielding part 70 may have a higher reflectance to the ultraviolet light 52 than the outer wall of the light-shielding part 70.
[0056] The light-shielding part 70 may be fixed to the liquid-contacting container 10 by screws, adhesive, or the like. The adhesive used may be one that softens at a temperature lower than the heat resistance temperature of the light-shielding part 70 and the liquid-contacting container 10. The light-shielding part 70 may be fixed mechanically by matching its shape and dimensions with the wall surface of the liquid-contacting container 10. The light-shielding part 70 may be fixed to the liquid-contacting container 10 by heating or other methods. Maintenance can be facilitated by replacing only the light-shielding part 70, which is easily deteriorated by irradiation with ultraviolet light 52.
[0057] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the description of the claims that such modifications and improvements can also be included in the technical scope of the present invention. [Explanation of symbols]
[0058] 10...liquid-contacting vessel, 12...internal space, 14...dirt calculation control section, 20...measurement light irradiating optical system, 22...measurement light, 24...measurement light window, 30...scattered light detection optical system, 32...scattered light, 34...scattered light window, 36...scattered light detection signal line, 40...transmitted light detection optical system, 42...transmitted light, 44...transmitted light window, 46...transmitted light detection signal line, 48...measured light, 50...ultraviolet light irradiating optical system, 52...ultraviolet light, 54...ultraviolet light window, 56...ultraviolet light detection signal line, 58...detection optical system, 60...flow rate control section, 62...liquid flow pipe, 66...flow rate control signal line, 70...light shielding section, 100...water quality analysis device
Claims
1. A water quality analyzer for analyzing measurement target water, a liquid-contacting vessel having an internal space through which the water to be measured flows; a measurement light irradiation optical system that irradiates the internal space with measurement light; an ultraviolet light irradiation optical system that irradiates the internal space with ultraviolet light; a detection optical system for analyzing the measurement target water based on the measured light from the liquid contact container; a dirt calculation control unit that calculates a dirt index that represents a degree of dirt of the liquid contact container based on the analysis result of the detection optical system; Equipped with The dirt calculation control unit controls the intensity of the ultraviolet light in accordance with the result of the dirt index. Water quality analyzer.
2. The dirt calculation control unit increases the intensity of the ultraviolet light when the dirt index value becomes greater than a predetermined value. The water quality analysis device according to claim 1 .
3. The predetermined value is determined according to the type of the water to be measured. The water quality analysis device according to claim 2.
4. The ultraviolet light irradiation optical system intermittently irradiates the ultraviolet light while the water quality analyzer is analyzing the measurement target water. The water quality analysis device according to claim 1 .
5. The ultraviolet light irradiation optical system and the measurement light irradiation optical system alternately irradiate the ultraviolet light and the measurement light while the water quality analysis device is analyzing the measurement target water. The water quality analysis device according to claim 4.
6. The ultraviolet light has a greater degree of diffusion than the measurement light. The water quality analysis device according to claim 1 .
7. The liquid-contacting container includes: a scattered light window through which the light to be measured passes; an ultraviolet light window through which the ultraviolet light passes; having The ultraviolet light window is disposed at a position facing the scattered light window across the internal space. The water quality analysis device according to claim 1 .
8. The flow rate control unit controls the flow rate of the measurement target water to remove the contaminants. The water quality analysis device according to claim 1 .
9. The water quality analysis device is The dirt calculation control unit calculates the dirt index, and when the dirt index is greater than a predetermined value, The dirt calculation control unit increases the amount of light and the duty ratio of the ultraviolet light, The flow rate control unit repeatedly performs an operation of increasing the flow rate of the measurement target water. The water quality analysis device according to claim 8.
10. The liquid-contacting container includes: a scattered light window through which the light to be measured passes; an ultraviolet light window through which the ultraviolet light passes; having the liquid contact container has a light shielding portion provided in the internal space and configured to guide the ultraviolet light from the ultraviolet light window to the scattered light window; The inner wall of the light-shielding portion reflects the ultraviolet light. The water quality analysis device according to any one of claims 1 to 9.