Water quality analysis device

Abstract

A water quality analysis device for measuring the concentration of a target substance contained in a sample water is provided, comprising: a wall portion that transmits light; a flow cell having an internal space enclosed by said wall portion, through which the sample water passes; a light source that irradiates light toward said flow cell; a light source monitor that detects the amount of light irradiated by said light source, which is the amount of light from said light source; a transmitted light detector that detects the amount of transmitted light that passes through said flow cell, which is the amount of transmitted light; and a contamination detector that detects contamination of said wall portion of said flow cell based on said light source amount and said transmitted light amount.

Description

Technology Field

[0001] The present invention relates to a water quality analysis device. Background Technology

[0002] Conventionally, a water quality analysis device for analyzing the water quality of a sample water is known (e.g., see Patent Documents 1 and 2). Prior art literature 1. Japanese Patent Publication No. 6436266 2. Japanese Patent Publication No. 2006-194659 The problem to be solved

[0003] In a water quality analysis device, it is desirable to be able to detect contamination of the flow cell through which the sample water flows with good precision. means of solving the problem

[0004] To solve the above problem, in a first embodiment of the present invention, a water quality analysis device is provided for measuring the concentration of a target substance contained in a sample water. The water quality analysis device may include a flow cell having a wall portion that transmits light and an internal space enclosed by said wall portion, through which the sample water passes. The water quality analysis device may include a light source that irradiates light toward said flow cell. Any one of the water quality analysis devices may include a light source monitor that detects the amount of light from said light source irradiated by said light source. Any one of the water quality analysis devices may include a transmitted light detector that detects the amount of transmitted light that passes through said flow cell. Any one of the water quality analysis devices may include a contamination detector that detects contamination of said wall portion of said flow cell based on said light source amount and said transmitted light amount.

[0005] In any one of the above water quality analysis devices, the contamination detection unit may detect contamination of the wall portion based on the ratio of the light source amount to the transmitted light amount.

[0006] Any one of the above water quality analysis devices may be equipped with a cleaning unit for cleaning contamination of the wall portion of the flow cell. In any one of the above water quality analysis devices, the contamination detection unit may determine whether the cleaning of the flow cell has been completed based on the amount of light from the light source and the amount of transmitted light detected after cleaning the flow cell.

[0007] In any one of the above water quality analysis devices, the contamination detection unit may output a notification indicating that the cleaning has not been completed if the cleaning is not completed within a set period from the start of cleaning of the flow cell.

[0008] In any one of the above water quality analysis devices, the contamination detection unit may change the cleaning method in the cleaning unit if the cleaning is not completed within a set period from the start of cleaning of the flow cell.

[0009] In any one of the above water quality analysis devices, the cleaning unit may select a cleaning method of the flow cell based on at least one of the light source amount and the transmitted light amount.

[0010] In any one of the above water quality analysis devices, the cleaning unit may adjust the pH of the cleaning solution flowing into the flow cell based on the ratio of the amount of light from the light source and the amount of light transmitted.

[0011] In any one of the above water quality analysis devices, the cleaning unit may select a cleaning method of the flow cell based on the history of the sample water that was previously flowed through the flow cell.

[0012] In any one of the above water quality analysis devices, the contamination detection unit may detect contamination of the wall portion by using the amount of transmitted light when the sample water is not flowing through the flow cell.

[0013] In any one of the above water quality analysis devices, the contamination detection unit may detect contamination of the wall portion by using the amount of transmitted light while the sample water is flowing through the flow cell.

[0014] Any one of the above water quality analysis devices may be equipped with a scattered light detection unit that detects the amount of scattered light, which is the amount of scattered light from the sample water. In any one of the above water quality analysis devices, the contamination detection unit may further detect contamination of the wall portion of the flow cell based on the amount of scattered light.

[0015] Any one of the above water quality analysis devices may be provided with a turbidity measuring unit that measures the turbidity of the sample water based on at least one of the amount of scattered light detected by the scattered light detector and the amount of transmitted light detected by the transmitted light detector.

[0016] The above summary of the invention does not list all of the features of the invention. In addition, sub-combinations of these groups of features may also constitute the invention. Brief explanation of the drawing

[0017] FIG. 1 is a drawing showing an example of a water quality analysis device (100) according to one embodiment of the present invention. FIG. 2 is a diagram showing an example of light source light quantity, transmitted light quantity, and light quantity ratio (transmitted light quantity / light source light quantity). FIG. 3 is a flowchart showing an example of operation of a water quality analysis device (100). FIG. 4 is a flowchart showing another example of operation of the water quality analysis device (100). FIG. 5 is a flowchart showing another example of operation of the water quality analysis device (100). FIG. 6 is a diagram showing an example of the configuration of a measurement light detection unit (30) and a concentration measurement unit (32). Specific details for implementing the invention

[0018] The present invention will be described below through embodiments thereof, but the following embodiments do not limit the invention according to the claims. Furthermore, not all combinations of features described within the embodiments are essential to the means of solving the invention.

[0019] FIG. 1 is a diagram showing an example of a water quality analysis device (100) according to one embodiment of the present invention. The water quality analysis device (100) measures the concentration of a target substance included in a sample water. The water quality analysis device (100) of the present example comprises a light source (10), a flow cell (20), a light source monitor (50), a measurement light detection unit (30), a concentration measurement unit (32), a transmitted light detection unit (70), a contamination detection unit (40), and a cleaning unit (60). The light source monitor (50), the measurement light detection unit (30), and the transmitted light detection unit (70) are devices that detect the amount of light received using a light receiving element such as a CCD or a photodiode. In this specification, the amount of light refers to the total amount (lm / S) of light flux (light beam) passing through a predetermined surface within a predetermined unit time, and the intensity of light (cd) may be used as the amount of light. The light source monitor (50), the measurement light detector (30), and the transmitted light detector (70) output an electrical signal according to the amount of light detected. The light source monitor (50), the measurement light detector (30), and the transmitted light detector (70) may perform signal processing, such as amplification or noise removal, on the electrical signal.

[0020] A light source (10) irradiates light (91) toward a flow cell (20). The flow cell (20) has a wall portion (22) and an internal space (24). At least a portion of the wall portion (22) is formed of a material that transmits at least a portion of the components of the light (91) irradiated by the light source (10). At least a portion of the wall portion (22) is formed of, for example, glass. The wall portion (22) may have a window portion through which light is incident or emitted, and a support portion that supports the window portion. In this specification, the window portion through which light is incident or emitted may be described as the wall portion (22). The internal space (24) is surrounded by the wall portion (22). Sample water passes through the internal space (24). As an example, the wall portion (22) has a cylindrical shape. In FIG. 1, a cross-section of the wall (22) and the interior space (24) is schematically shown.

[0021] The measurement light detection unit (30) detects the measurement light (92) from the flow cell (20). The measurement light detection unit (30) measures the amount of light at at least one wavelength of the measurement light (92). The measurement light (92) is light emitted from the flow cell (20) when light (91) is irradiated from the light source (10) while the sample water is present in the flow cell (20). The measurement light (92) may include fluorescence emitted from the measurement target substance when the light (91) is irradiated onto the measurement target substance contained in the sample water. In this case, the measurement light detection unit (30) may measure the amount of light of the measurement light (92) at a wavelength different from that of the light (91).

[0022] The concentration measuring unit (32) measures the concentration of the target substance contained in the sample water based on the measurement result from the measurement light detection unit (30). The sample water is, for example, tap water, sewage water, seawater, wastewater from factories, etc., but is not limited thereto. When the sample water contains fluorescent substances such as polycyclic aromatic hydrocarbons (PAH), when ultraviolet light (91) is irradiated onto the sample water, fluorescence (measurement light (92)) of the specific wavelength of the substance is generated. Since the fluorescence intensity is proportional to the concentration of the fluorescent substance contained therein, the concentration of the fluorescent substance, which is the target substance, can be measured with good precision by measuring the amount of light of the measurement light (92) at the corresponding wavelength.

[0023] If contamination occurs on the wall (22) of the flow cell (20), the intensity of the light (91) or the measurement light (92) is attenuated due to the contamination. If the aforementioned window portion is installed on the wall (22), the contamination of the wall (22) refers to contamination of the window portion. Contamination of the wall (22) is, for example, foreign matter attached to the inner or outer surface of the wall (22). If the intensity of the light (91) or the measurement light (92) is attenuated, an error occurs in the measurement result of the concentration of the substance to be measured. Therefore, it is desirable to be able to detect with good precision whether contamination has occurred on the wall (22) of the flow cell (20).

[0024] The contamination detection unit (40) detects contamination in the wall portion (22). The contamination detection unit (40) may detect contamination in the wall portion (22) by triggering a predetermined operation in the water quality analysis device (100). For example, the contamination detection unit (40) detects contamination in the wall portion (22) after cleaning when the cleaning unit (60) cleans the wall portion (22) of the flow cell (20). The cleaning unit (60) may clean the inner surface of the wall portion (22) by flowing a cleaning liquid into the internal space (24) of the flow cell (20), or may clean the wall portion (22) by contacting a brush or the like to the inner or outer surface of the wall portion (22). The cleaning unit (60) may clean the wall portion (22) whenever a set cleaning period has elapsed. The contamination detection unit (40) may notify the cleaning unit (60) that cleaning has not been completed when the degree of contamination of the wall (22) deviates from the allowable range. Upon receiving such notification, the cleaning unit (60) may clean the wall (22) of the flow cell (20) again.

[0025] The contamination detection unit (40) may detect contamination of the wall (22) whenever a set detection period has elapsed. The contamination detection unit (40) may detect contamination of the wall (22) at predetermined detection periods, and when the degree of contamination of the wall (22) deviates from the allowable range, the cleaning unit (60) may clean the wall (22). The contamination detection unit (40) may also detect contamination of the wall (22) according to instructions from a user, etc. In this case as well, the contamination detection unit (40) may have the cleaning unit (60) clean the wall (22) when the degree of contamination of the wall (22) deviates from the allowable range.

[0026] When the contamination detection unit (40) detects contamination of the wall unit (22), the light source (10) irradiates light (91) having a predetermined wavelength component toward the flow cell (20). The wavelength of the light (91) when detecting contamination may be different from the wavelength of the light (91) when measuring the fluorescence of the target substance. The light source (10) may have a light source unit that irradiates light (91) for detecting contamination and a light source unit that irradiates light (91) for detecting fluorescence.

[0027] The transmitted light detection unit (70) detects transmitted light (94) that has passed through the flow cell (20) after light (91) is incident on the flow cell (20). For example, the transmitted light detection unit (70) may detect light emitted by the light (91) traveling straight through the interior of the flow cell (20) as transmitted light (94). The wall portion (22) may be equipped with a window portion into which light (91) is incident, a window portion into which measurement light (92) is emitted, and a window portion into which transmitted light is emitted. The transmitted light detection unit (70) detects the amount of transmitted light, which is the amount of transmitted light (94). The transmitted light detection unit (70) may detect the amount of transmitted light of a set wavelength. The transmitted light detection unit (70) outputs an electrical signal indicating the amount of transmitted light to the contamination detection unit (40).

[0028] When contamination is attached to the wall (22), the intensity of the light is attenuated due to the contamination, so the amount of transmitted light (94) is reduced. For this reason, the degree of contamination of the wall (22) can be estimated by detecting how much the amount of transmitted light (94) is attenuated relative to the amount of light (91) emitted by the light source (10). On the other hand, due to factors such as the deterioration of the light source (10), the amount of light (91) emitted from the light source (10) may change over time even if the setting value for the light source (10) is the same. If the amount of light (91) changes, the amount of transmitted light (94) also changes. For this reason, it is difficult to detect contamination of the wall (22) with good precision solely by the transmitted light (94).

[0029] The water quality analysis device (100) of the present example detects the amount of light source light, which is the amount of light (91) irradiated by the light source (10), by the light source monitor (50). The light source monitor (50) detects the amount of light source light of the light (91) before it is incident on the flow cell (20). The light source monitor (50) may receive branched light (93) which is a portion of the light (91) branched.

[0030] The contamination detection unit (40) detects contamination of the wall portion (22) of the flow cell (20) based on the amount of light source light and the amount of transmitted light. The contamination detection unit (40) corrects the amount of transmitted light based on the amount of light source light and detects contamination of the wall portion (22) based on the correction result. For example, the contamination detection unit (40) corrects the amount of transmitted light so that the amount of light source light increases as the amount of light source light decreases, and determines that the degree of contamination of the wall portion (22) is greater as the corrected amount of transmitted light decreases. As an example, the contamination detection unit (40) detects contamination of the wall portion (22) based on the ratio of the amount of light source light and the amount of transmitted light (amount of transmitted light / amount of light source light). The contamination detection unit (40) determines that the degree of contamination is greater as the corresponding ratio of light source light decreases. In this way, by detecting contamination of the wall (22) using the amount of light source light and the amount of transmitted light, the effects of deterioration of the light source (10) can be reduced, and contamination of the wall (22) can be detected with good precision. The amount of light source light and the amount of transmitted light may be measured without flowing sample water through the flow cell (20).

[0031] FIG. 2 is a diagram showing an example of light source light quantity, transmitted light quantity, and light quantity ratio (transmitted light quantity / light source light quantity). The vertical axis in FIG. 2 represents the light quantity or the light quantity ratio. FIG. 2 also shows the light source light quantity, transmitted light quantity, and light quantity ratio in multiple states A, B, C, and D. As an example, state A is the state at the time of factory shipment, in which there is no contamination of the wall (22) and no deterioration of the light source (10). State B is a state in which there is contamination of the wall (22) and the light source (10) is not deteriorated. State C is a state in which there is no contamination of the wall (22) and the light source (10) is deteriorated. State D is a state in which there is contamination of the wall (22) and the light source (10) is deteriorated. The degree of contamination of the wall portion (22) in states B and D is the same, and the degree of deterioration of the light source (10) in states C and D is the same.

[0032] FIG. 2 shows, by dashed lines, a determination criterion for detecting the presence or absence of contamination of the wall (22) based solely on the amount of transmitted light, and a determination criterion for detecting the presence or absence of contamination of the wall (22) based on the light quantity ratio (amount of transmitted light / amount of light source light). The determination criterion is pre-set by a user, etc. For example, if the amount of light or the light quantity ratio is greater than the determination criterion, it is determined as "no contamination," and if the amount of light or the light quantity ratio is less than the determination criterion, it is determined as "contamination present."

[0033] If contamination of the wall (22) is detected based solely on the amount of transmitted light, contamination in states B and D can be detected, but there are cases where contamination in state C, where there is no contamination in the wall (22), is misidentified as "contamination present." If only the amount of transmitted light is used, it is not possible to distinguish between cases where the amount of transmitted light is attenuated due to the deterioration of the light source (10) and cases where the amount of transmitted light is attenuated due to contamination of the wall (22). Therefore, contamination of the wall (22) is misidentified when the light source (10) is deteriorated. Furthermore, as with states B and D, even though the degree of contamination of the wall (22) is originally the same, the degree of contamination is detected differently due to the deterioration of the light source (10).

[0034] On the other hand, by using the light intensity ratio (transmitted light intensity / light source light intensity), the effect of deterioration of the light source (10) can be reduced. For example, as in state C, the effect of deterioration of the light source (10) can be corrected to detect contamination of the wall portion (22) with good precision. The contamination detection unit (40) may detect whether there is contamination of the wall portion (22) by comparing the light intensity ratio with the contamination judgment standard. The contamination detection unit (40) may determine the degree of contamination based on the magnitude of the discrepancy between the light intensity ratio and the contamination judgment standard.

[0035] FIG. 3 is a flowchart showing an example of operation of a water quality analysis device (100). The water quality analysis device (100) begins measuring the concentration of a target substance in a sample water according to a predetermined trigger signal. The trigger signal may be input by operation by a user, automatically input according to changes in the surrounding environment, automatically input whenever a predetermined period has elapsed, or input according to other factors.

[0036] In the measurement step (S202), the concentration measuring unit (32) measures the number of samples. The concentration measuring unit (32) measures the concentration of the substance to be measured based on the measurement light (92) measured by the measurement light detection unit (30). As described above, the measurement light (92) may be fluorescence emitted from the number of samples. In this case, the concentration measuring unit (32) can measure the concentration of the fluorescent substance based on the amount of light of the measurement light (92).

[0037] In the continuous use step (S204), the water quality analysis device (100) measures the concentration of a target substance in the sample water continuously or intermittently during a preset continuous use period. When the continuous use period has elapsed, in the cleaning step (S206), the cleaning unit (60) performs cleaning inside the flow cell (20). The cleaning unit (60) may clean the flow cell (20) by flowing clear water or a cleaning solution containing chemicals into the internal space (24) of the flow cell (20), or clean the flow cell (20) by sweeping the internal space (24) with a brush or similar material, or clean the flow cell (20) by combining these methods.

[0038] After the cleaning unit (60) performs a predetermined cleaning process, in the cleaning completion determination step (S208), the contamination detection unit (40) determines whether the cleaning of the flow cell (20) is completed. The contamination detection unit (40) may determine whether there is contamination in the wall portion (22) of the flow cell (20), and if it is determined that there is no contamination, it may determine that the cleaning is completed. The contamination detection unit (40) may determine whether there is contamination by comparing the light quantity ratio (transmitted light quantity / light source light quantity) with a predetermined contamination determination standard, as shown in FIG. 2. In the cleaning completion determination step (S208), the transmitted light quantity and light source light quantity may be measured when clear water is filled in the internal space (24) of the flow cell (20), or the transmitted light quantity and light source light quantity may be measured when no liquid is filled in the internal space (24).

[0039] In the cleaning completion determination step (S208), if it is determined that cleaning is complete, the water quality analysis device (100) may repeat the processing from the measurement step (S202) or terminate the operation. In the cleaning completion determination step (S208), if it is determined that cleaning is not complete, the cleaning unit (60) repeats the processing of the cleaning step (S206). If the contamination detection unit (40) does not end cleaning within a set period from the start of cleaning of the flow cell (20), it may output a notification indicating that cleaning has not ended. In this case, the water quality analysis device (100) may repeat the processing from the measurement step (S202) or terminate the operation.

[0040] In the cleaning step (S206), the cleaning unit (60) may select a cleaning method for the flow cell (20) based on at least one of the light source amount and the transmitted light amount. The selection of the cleaning method may be the selection of characteristics of the cleaning solution to be used for cleaning, or the selection of a tool to be used for cleaning (whether to use a brush or a cleaning solution, etc.). The cleaning unit (60) may select a cleaning method according to the degree of contamination determined by the light amount ratio (light source amount and transmitted light amount). In this case, the light amount ratio may be measured in the cleaning step (S206). The cleaning unit (60) may adjust the pH of the cleaning solution flowing through the flow cell (20) according to the degree of contamination. The greater the degree of contamination, the greater the deviation of the pH of the cleaning solution from the neutral value may be. The extent to which the pH is changed according to the degree of contamination may be determined experimentally in advance and set in the cleaning unit (60).

[0041] The cleaning unit (60) may select a cleaning method based on the history of the sample water that has flowed through the flow cell (20) in the past. In this example, the cleaning unit (60) may select a cleaning method according to the type of sample water that has flowed through the continuous use step (S204). The type of sample water may be the type of substance contained in the sample water. For example, whether to use an acidic or alkaline cleaning solution may be selected according to the type of sample water. Since the contaminants attached to the flow cell (20) can be estimated according to the type of sample water, the cleaning unit (60) may select a cleaning solution according to the type of sample water. The cleaning unit (60) may pre-set which cleaning solution to select for each substance. In the water quality analysis device (100) of this example, it is preferable that the part where the cleaning solution flows be formed of a material that does not deteriorate even when an acidic or alkaline cleaning solution flows.

[0042] The cleaning unit (60) may estimate the type of material attached to the wall (22) based on the light intensity ratio (light source light intensity and transmitted light intensity) at multiple wavelengths, and select a cleaning method according to the estimation result. The cleaning unit (60) may estimate the type of material attached to the wall (22) by comparing the shape of the spectrum of the light intensity ratio with the transmission spectrum determined according to the type of each material. By using a light intensity ratio that corrects for the deterioration of the light source (10), the type of material attached to the wall (22) can be estimated with good precision.

[0043] FIG. 4 is a flowchart showing another example of operation of a water quality analysis device (100). The operation of this example differs from the example of FIG. 3 in that it further includes a step of determining the elapsed time (S210) and a step of changing the cleaning method (S212). Other steps are the same as those of FIG. 3.

[0044] In this example, if it is determined that cleaning is not completed in the cleaning completion determination step (S208), the time elapsed determination step (S210) is performed. In the time elapsed determination step (S210), the contamination detection unit (40) determines whether a set period has elapsed since the start of cleaning of the flow cell (20). If the set period has not yet elapsed, the contamination detection unit (40) causes the cleaning unit (60) to repeat the cleaning step (S206). If cleaning is not completed within the set period, in the cleaning method change step (S212), the contamination detection unit (40) changes the cleaning method of the cleaning unit (60). If cleaning is not completed within the set period, the cleaning unit (60) may select a more powerful cleaning method. For example, if cleaning is not completed within the set period using clear water, the cleaning unit (60) may perform cleaning again using a cleaning solution containing a chemical or a surfactant. Additionally, the cleaning unit (60) may adjust the pH of the cleaning solution if cleaning is not completed within a set period using the cleaning solution.

[0045] FIG. 5 is a flowchart showing another example of operation of a water quality analysis device (100). The operation of this example differs from the example of FIG. 3 or FIG. 4 in that it further includes a contamination detection step (S205). Other steps are the same as those of FIG. 3 or FIG. 4. FIG. 5 shows an example in which a contamination detection step (S205) is added to the example of FIG. 3, but a contamination detection step (S205) may also be added to the example of FIG. 4.

[0046] The contamination detection unit (40) of the present example detects contamination of the wall (22) using the amount of transmitted light while the sample water is flowing through the flow cell (20). Specifically, it detects contamination of the wall (22) using the amount of light source light and the amount of transmitted light measured during the continuous use period in the continuous use step (S204). The contamination detection unit (40) may detect contamination of the wall (22) at a predetermined interval during the continuous use period. In the example of FIG. 5, contamination of the wall (22) is detected during the contamination detection step (S205) during the continuous use period. If it is determined that there is no contamination of the wall (22) during the contamination detection step (S205), the water quality analysis device (100) continues the processing of the continuous use step (S204). If it is determined that there is contamination on the wall (22) in the contamination detection step (S205), the water quality analysis device (100) performs treatment after the cleaning step (S206). The treatment after the cleaning step (S206) is the same as the example in FIG. 3 or FIG. 4.

[0047] FIG. 6 is a diagram showing an example of the configuration of a measurement light detection unit (30) and a concentration measurement unit (32). The measurement light detection unit (30) of the present example has a fluorescence detection unit (33) and a scattered light detection unit (31). The concentration measurement unit (32) has a signal processing unit (35) and a turbidity measurement unit (34). In addition, the water quality analysis device (100) of the present example has a light source (10-1) and a light source (10-2). The light source (10-1) is a light source that irradiates light (91-1) for measuring scattered light (measurement light (92-1)), and the light source (10-2) is a light source that irradiates light (91-2) for measuring fluorescence (measurement light (92-2)). The light (91-1) and the light (91-2) may have different wavelength components. The light (91-1) from the light source (10-1) is also used to measure the transmitted light (94). That is, some of the light (91-1) is emitted as scattered light, and other parts are emitted as transmitted light.

[0048] The water quality analysis device (100) of the present example measures the concentration of a fluorescent substance contained in the sample water based on the amount of light of the fluorescence (measurement light (92-2)). On the other hand, if the sample water contains suspended matter, the amount of light (91-2) or measurement light (92-2) may be attenuated due to the influence of light scattering or absorption from the suspended matter (particles). This phenomenon is called the inner filter effect. Due to the inner filter effect, there is a risk that the measurement accuracy of the fluorescence intensity will deteriorate in an environment where the concentration of suspended matter (hereinafter, turbidity) is high.

[0049] The water quality analysis device (100) of the present example corrects the amount of light of the measured light (92-2) based on the turbidity of the sample water in order to improve the measurement precision of the fluorescence intensity. The water quality analysis device (100) measures the turbidity of the sample water along with the fluorescence intensity. The water quality analysis device (100) measures the turbidity of the sample water from the amount of scattered light or transmitted light from the sample water. The amount of scattered light of the sample water is detected by the scattered light detection unit (31). The amount of transmitted light of the sample water may be detected by the transmitted light detection unit (70) shown in FIG. 1.

[0050] First, the measurement of turbidity of the sample water is described. A light source (10-1) irradiates light (91-1), which is infrared light, onto the sample water inside the flow cell (20). The light source (10-1) is, for example, an LED (Light Emitting Diode) or a laser irradiation device.

[0051] By irradiating the sample water inside the flow cell (20) with light (91-1), scattered light (measurement light (92-1)) or transmitted light (94) (see FIG. 1) is generated. The scattered light is generated by light scattering from suspended matter contained in the sample water. The higher the concentration of suspended matter, the greater the amount of scattered light. The transmitted light (94) is light that is not absorbed or scattered by the suspended matter in the sample water. The higher the concentration of suspended matter, the greater the amount of transmitted light (94).

[0052] The turbidity measuring unit (34) may measure the turbidity of the sample water based on at least one of the light amount of the measuring light (92-1) detected by the scattered light detection unit (31) and the light amount of the transmitted light (94) detected by the transmitted light detection unit (70). The turbidity measuring unit (34) may measure the turbidity from the light amount of either the measuring light (92-1) or the transmitted light (94). As described above, since the light amounts of the measuring light (92-1) and the transmitted light (94) change according to the turbidity, the turbidity can be estimated from these light amounts. The turbidity measuring unit (34) may calculate the turbidity using the ratio of the light amounts of the measuring light (92-1) and the transmitted light (94) (light amount of the measuring light (92-1) / light amount of the transmitted light (94)). The higher the turbidity, the greater the ratio of the corresponding light amounts.

[0053] Next, the measurement of the concentration of the fluorescent substance in the sample water is described. A light source (10-2) irradiates light (91-2) onto the sample water inside the flow cell (20). The light (91-2) is, for example, ultraviolet light. The light source (10-2) is, for example, a xenon flash lamp, an LED, or a laser irradiation device.

[0054] The light source (10-2) may include an optical filter internally. Because it includes an optical filter, the light source (10-2) can irradiate light within a predetermined wavelength range of light (91-2) onto the flow cell (20). In this example, the material to be measured is PAH. Fluorescence is emitted most efficiently when the wavelength of the excitation light is around 250 nm. Therefore, the transmission wavelength of the optical filter of the light source (10-2) is set to, for example, 200 nm or more and 300 nm or less.

[0055] By irradiating the sample water inside the flow cell (20) with light (91-2), fluorescence (measurement light (92-2)) is generated. The fluorescence detector (33) detects the amount of light of the measurement light (92-2). The fluorescence detector (33) may include an optical filter inside. Because it includes an optical filter, the fluorescence detector (33) can receive light within a predetermined wavelength range of the measurement light (92-2). In this example, the substance to be measured is PAH. For PAH, when the wavelength of the excitation light is around 250 nm, the fluorescence wavelength is around 350 nm. Therefore, the transmission wavelength of the optical filter inside the fluorescence detector (33) is set to, for example, 300 nm or more and 400 nm or less.

[0056] The signal processing unit (35) calculates the concentration of a fluorescent substance contained in the sample water from the amount of light of the measurement light (92-2) detected by the fluorescence detection unit (33). As described above, the amount of light of the measurement light (92-2) is attenuated by the turbidity of the sample water. The signal processing unit (35) calculates the concentration of the fluorescent substance by correcting the amount of light of the measurement light (92-2) based on the turbidity measured by the turbidity measurement unit (34). The relationship between the turbidity and the amount of correction may be determined experimentally in advance and set in the signal processing unit (35). Through this processing, the water quality analysis device (100) can measure the concentration of the fluorescent substance in the sample water with good precision.

[0057] As described in FIG. 5, when detecting contamination of the wall portion (22) using the amount of transmitted light while the sample water is flowing through the flow cell (20), the amount of transmitted light may be attenuated depending on the turbidity of the sample water. In this case, the detection precision of contamination of the wall portion (22) may be degraded.

[0058] The contamination detection unit (40) may detect contamination of the wall portion (22) of the flow cell (20) by using the amount of scattered light (amount of scattered light) detected by the scattered light detection unit (31) in addition to the amount of transmitted light and the amount of light source light. The contamination detection unit (40) may use the amount of transmitted light common to the turbidity measurement. The contamination detection unit (40) may use the turbidity calculated by the turbidity measurement unit (34) instead of the amount of scattered light. The contamination detection unit (40) may correct the amount of transmitted light using the amount of scattered light. That is, when the amount of scattered light is large, it is thought that the amount of transmitted light is greatly attenuated due to suspended matter, so the amount of transmitted light may be corrected to a larger value as the amount of scattered light increases. By doing so, the influence of the turbidity of the sample water is reduced, and contamination of the wall portion (22) can be detected with good precision.

[0059] In another example, the contamination detection unit (40) may determine the contamination of the wall (22) under the condition that the amount of scattered light or turbidity is below a reference value. That is, the contamination detection unit (40) may determine the contamination of the wall (22) under the condition that the attenuation of the amount of transmitted light due to the sample water is small. By doing so, the influence of the turbidity of the sample water is reduced, and the contamination of the wall (22) can be detected with good precision.

[0060] In the example of FIG. 6, the amount of transmitted light used for measuring turbidity and the amount of transmitted light used for measuring pollution can be detected by a common transmitted light detector (70). In addition, the light source (10) used for measuring turbidity and the light source (10) used for measuring pollution can be common. Because of this, the number of components of the water quality analysis device (100) can be reduced.

[0061] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the embodiments. It is obvious to those skilled in the art that various modifications or improvements can be made to the embodiments. It is evident from the claims that forms with such modifications or improvements may also be included within the technical scope of the present invention.

[0062] It should be noted that the execution order of each process, such as operations, sequences, steps, and stages, in the apparatus, system, program, and method shown in the claims, specification, and drawings is not specifically specified as “before” or “prior,” and can be realized in any order unless the output of a preceding process is used in a subsequent process. Even if the operation flow in the claims, specification, and drawings is described using terms such as “first,” or “next,” for convenience, this does not mean that it is mandatory to carry out the process in this order. Explanation of the symbols

[0063] 10: Light source, 20: Flow cell, 22: Wall section, 24: Internal space, 30: Measurement light detector, 31: Scattered light detector, 32: Concentration measuring section, 33: Fluorescence detector, 34: Turbidity measuring section, 35: Signal processing section, 40: Contamination detector, 50: Light source monitor, 60: Cleaning section, 70: Transmitted light detector, 91: Light, 92: Measurement light, 93: Branched light, 94: Transmitted light, 100: Water quality analysis device

Claims

Claim 1 A water quality analysis device for measuring the concentration of a target substance contained in a sample water, comprising: a wall portion that transmits light; a flow cell having an internal space enclosed by said wall portion, through which the sample water passes; a light source that irradiates light toward said flow cell; a light source monitor that detects the amount of light irradiated by said light source, which is the amount of light from said light source; a transmitted light detector that detects the amount of transmitted light that has passed through said flow cell, which is the amount of transmitted light; a contamination detector that detects contamination of said wall portion of said flow cell based on said light source amount and said transmitted light amount; a cleaning unit that cleans the contamination of said wall portion of said flow cell; and a scattered light detector that detects the amount of scattered light that is the amount of scattered light from said sample water, wherein the contamination detector detects contamination of said wall portion using said transmitted light amount while the sample water is flowing through said flow cell; the cleaning unit initiates cleaning of said flow cell when there is contamination of said wall portion; and the contamination detector A water quality analysis device for detecting contamination of the wall portion of the flow cell, under the condition that the turbidity of the sample water, measured based on at least one of the amount of scattered light detected by the scattered light detection unit and the amount of transmitted light detected by the transmitted light detection unit, is below a reference value. Claim 2 A water quality analysis device for measuring the concentration of a target substance contained in a sample water, comprising: a flow cell having a wall portion that transmits light and an internal space enclosed by said wall portion, through which the sample water passes; a light source that irradiates light toward said flow cell; a light source monitor that detects the amount of light irradiated by said light source, which is the amount of light from said light source; a transmitted light detector that detects the amount of transmitted light that passes through said flow cell, which is the amount of transmitted light; a contamination detector that detects contamination of said wall portion of said flow cell based on said light source amount and said transmitted light amount; a cleaning unit that cleans the contamination of said wall portion of said flow cell; and a scattered light detector that detects the amount of scattered light, which is the amount of scattered light from said sample water, wherein the contamination detector corrects said transmitted light amount when the sample water is flowing through said flow cell using said scattered light amount, and based on said light source amount and said transmitted light amount after correction, the contamination of said wall portion of said flow cell A water quality analysis device that detects, and the cleaning unit initiates cleaning of the flow cell when there is contamination of the wall. Claim 3 A water quality analysis device for measuring the concentration of a target substance contained in a sample water, comprising: a wall portion that transmits light; a flow cell having an internal space enclosed by said wall portion, through which the sample water passes; a light source that irradiates light toward said flow cell; a light source monitor that detects the amount of light irradiated by said light source, which is the amount of light from said light source; a transmitted light detector that detects the amount of transmitted light that passes through said flow cell, which is the amount of transmitted light; and a contamination detector that detects contamination of said wall portion of said flow cell based on said light source amount and said transmitted light amount, wherein the contamination detector detects contamination of said wall portion using said transmitted light amount while the sample water is flowing through said flow cell; a scattered light detector that detects the amount of scattered light, which is the amount of scattered light from said sample water; and the turbidity of said sample water based on at least one of said scattered light amount detected by said scattered light detector and said transmitted light amount detected by said transmitted light detector. A water quality analysis device further comprising a turbidity measuring unit, wherein the contamination detection unit detects contamination of the wall portion of the flow cell under the condition that the turbidity of the sample water is below a standard value. Claim 4 A water quality analysis device according to any one of claims 1 to 3, wherein the contamination detection unit detects contamination of the wall portion based on the ratio of the amount of light from the light source to the amount of light transmitted. Claim 5 In paragraph 2, the contamination detection unit is a water quality analysis device that determines whether the cleaning of the flow cell has been completed based on the amount of light from the light source and the amount of light transmitted detected after the cleaning of the flow cell. Claim 6 In paragraph 5, the above-mentioned contamination detection unit outputs a notification indicating that cleaning has not been completed if cleaning is not completed within a set period from the start of cleaning of the flow cell. Claim 7 In claim 5, the above-mentioned contamination detection unit is a water quality analysis device that changes the cleaning method in the cleaning unit when the cleaning is not completed within a set period from the start of cleaning of the flow cell. Claim 8 A water quality analysis device according to claim 5, wherein the cleaning unit selects a cleaning method of the flow cell based on at least one of the light source amount and the transmitted amount. Claim 9 In claim 8, the cleaning unit is a water quality analysis device that adjusts the pH of the cleaning solution flowing into the flow cell based on the ratio of the light source amount and the transmitted light amount. Claim 10 In claim 5, the cleaning unit is a water quality analysis device that selects a cleaning method of the flow cell based on the type of sample water that was previously flowed through the flow cell. Claim 11 delete Claim 12 delete Claim 13 delete Claim 14 delete

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