Water quality analysis device

Abstract

Provided is a water quality analyzing device for measuring the concentration of a substance to be measured, contained in sample water, the water quality analyzing device comprising: a flow cell which comprises a wall portion through which light is transmitted, and an internal space enclosed by the wall portion, wherein the sample water passes through the internal space; a light source for emitting light toward the flow cell; a light source monitor for detecting a light source light intensity, which is a light intensity of the light emitted by the light source; a transmitted light detecting unit for detecting a transmitted light intensity, which is the light intensity of transmitted light that has been transmitted through the flow cell; and a dirt detecting unit for detecting dirt on the wall portion of the flow cell on the basis of the light source intensity and the transmitted light intensity.

Description

[Technical field]

[0001] The present invention relates to a water quality analyzer. [Background technology]

[0002] 2. Description of the Related Art Conventionally, water quality analyzers that analyze the quality of sample water are known (see, for example, Patent Documents 1 and 2). Patent Document 1 Patent No. 6436266 Patent Document 2: Japanese Patent Application Laid-Open No. 2006-194659 Problems to be Solved

[0003] In a water quality analyzer, it is preferable to be able to accurately detect contamination of a flow cell through which sample water flows.

[0004] In order to solve the above problems, a first aspect of the present invention provides a water quality analyzer for measuring a concentration of a measurement target substance contained in sample water. The water quality analyzer may include a flow cell having a light-transmitting wall and an internal space surrounded by the wall, the sample water passing through the internal space. The water quality analyzer may include a light source for irradiating light toward the flow cell. Any of the water quality analyzers may include a light source monitor for detecting a light source light amount, which is the amount of light irradiated by the light source. Any of the water quality analyzers may include a transmitted light detection unit for detecting a transmitted light amount, which is the amount of transmitted light that has passed through the flow cell. Any of the water quality analyzers may include a dirt detection unit for detecting dirt on a wall of the flow cell based on the light source light amount and the transmitted light amount.

[0005] In any of the water quality analysis devices described above, the dirt detection unit may detect dirt on the wall portion based on a ratio between the amount of light from the light source and the amount of transmitted light.

[0006] Any of the water quality analysis devices described above may include a cleaning unit that cleans dirt from the wall of the flow cell. In any of the water quality analysis devices described above, the dirt detection unit may determine whether 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 of the flow cell.

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

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

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

[0010] In any of the water quality analyzers described above, the cleaning unit may adjust a pH of the cleaning liquid to be caused to flow through the flow cell, based on a ratio between the amount of light from the light source and the amount of transmitted light.

[0011] In any of the water quality analyzers described above, the cleaning section may select a cleaning method for the flow cell based on a history of the sample water that has been flowed through the flow cell in the past.

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

[0013] In any of the water quality analysis devices described above, the dirt detection unit may detect dirt on the wall portion using the amount of transmitted light when the sample water is flowing through the flow cell.

[0014] Any of the water quality analyzers described above may include a scattered light detection unit that detects an amount of scattered light, which is an amount of light scattered from the sample water. In any of the water quality analyzers described above, the dirt detection unit may detect dirt on the wall of the flow cell further based on the amount of scattered light.

[0015] Any 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 detection unit and the amount of transmitted light detected by the transmitted light detection unit.

[0016] The above summary of the invention does not list all of the features of the present invention. In addition, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing an example of a water quality analysis device 100 according to an embodiment of the present invention. [Diagram 2] 4 is a diagram showing an example of a light source light amount, a transmitted light amount, and a light amount ratio (transmitted light amount / light source light amount). FIG. [Diagram 3] 4 is a flowchart showing an example of the operation of the water quality analysis device 100. [Figure 4] 13 is a flowchart showing another example of the operation of the water quality analyzer 100. [Diagram 5] 13 is a flowchart showing another example of the operation of the water quality analyzer 100. [Figure 6] 2 is a diagram showing an example of the configuration of a measurement light detection unit 30 and a concentration measurement unit 32. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0019] FIG. 1 is a diagram showing an example of a water quality analyzer 100 according to an embodiment of the present invention. The water quality analyzer 100 measures the concentration of a substance to be measured contained in a water sample. The water quality analyzer 100 of this embodiment includes a light source 10, a flow cell 20, a light source monitor 50, a measurement light detector 30, a concentration measuring unit 32, a transmitted light detector 70, a dirt detector 40, and a cleaning unit 60. The light source monitor 50, the measurement light detector 30, and the transmitted light detector 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 is the total amount (lm / S) of light flux passing through a specified surface within a specified unit time, but the light intensity (cd) may also 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 detected amount of light. 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] The light source 10 irradiates light 91 toward the flow cell 20. The flow cell 20 has a wall 22 and an internal space 24. At least a part of the wall 22 is formed of a material that transmits at least a part of the components of the light 91 irradiated by the light source 10. At least a part of the wall 22 is formed of, for example, glass. The wall 22 may have a window through which the light enters or exits, and a support that supports the window. In this specification, the window through which the light enters or exits may be described as the wall 22. The internal space 24 is surrounded by the wall 22. The sample water passes through the internal space 24. As an example, the wall 22 has a cylindrical shape. FIG. 1 shows a schematic cross section of the wall 22 and the internal space 24.

[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 in a state where the flow cell 20 contains sample water. The measurement light 92 may include fluorescence emitted from the measurement target substance when the measurement target substance contained in the sample water is irradiated with the light 91. In this case, the measurement light detection unit 30 may measure the amount of measurement light 92 at a wavelength different from that of the light 91.

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

[0023] When dirt occurs on the wall 22 of the flow cell 20, the dirt attenuates the intensity of the light 91 or the measurement light 92. When the wall 22 is provided with the window portion described above, the dirt on the wall 22 refers to dirt on the window portion. The dirt on the wall 22 is, for example, foreign matter attached to the inner or outer surface of the wall 22. When the intensity of the light 91 or the measurement light 92 attenuates, an error occurs in the measurement result of the concentration of the substance to be measured. For this reason, it is preferable to be able to accurately detect whether or not dirt has occurred on the wall 22 of the flow cell 20.

[0024] The dirt detection unit 40 detects dirt on the wall 22. The dirt detection unit 40 may detect dirt on the wall 22 by using a predetermined operation in the water quality analysis device 100 as a trigger. For example, when the cleaning unit 60 cleans the wall 22 of the flow cell 20, the dirt detection unit 40 detects dirt on the wall 22 after cleaning. The cleaning unit 60 may clean the inner surface of the wall 22 by flowing a cleaning liquid into the internal space 24 of the flow cell 20, or may clean the wall 22 by contacting a brush or the like with the inner or outer surface of the wall 22. The cleaning unit 60 may clean the wall 22 every time a set cleaning period has elapsed. When the degree of dirt on the wall 22 is outside the allowable range, the dirt detection unit 40 may notify the cleaning unit 60 that cleaning has not been completed. When the cleaning unit 60 receives the notification, it may clean the wall 22 of the flow cell 20 again.

[0025] The dirt detection unit 40 may detect dirt on the wall portion 22 every time a set detection period elapses. The dirt detection unit 40 may detect dirt on the wall portion 22 every predetermined detection period, and when the degree of dirt on the wall portion 22 falls outside the allowable range, cause the cleaning unit 60 to clean the wall portion 22. The dirt detection unit 40 may detect dirt on the wall portion 22 in response to an instruction from a user or the like. Even in this case, the dirt detection unit 40 may cause the cleaning unit 60 to clean the wall portion 22 when the degree of dirt on the wall portion 22 falls outside the allowable range.

[0026] When the dirt detection unit 40 detects dirt on the wall portion 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 dirt may be different from the wavelength of the light 91 when measuring the fluorescence of the measurement target substance. The light source 10 may have a light source unit that irradiates light 91 for detecting dirt, and a light source unit that irradiates light 91 for detecting fluorescence.

[0027] The transmitted light detection unit 70 detects transmitted light 94 that is generated when light 91 enters the flow cell 20 and transmits through the flow cell 20. For example, the transmitted light detection unit 70 may detect the light that travels straight through the inside of the flow cell 20 and exits as transmitted light 94. The wall 22 may be provided with a window through which the light 91 enters, a window through which the measurement light 92 exits, and a window through which the transmitted light exits. 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 at a set wavelength. The transmitted light detection unit 70 outputs an electrical signal indicating the amount of transmitted light to the dirt detection unit 40.

[0028] When dirt adheres to the wall 22, the dirt attenuates the light intensity, and the amount of transmitted light 94 decreases. Therefore, the degree of dirt on the wall 22 can be estimated by detecting the degree to which the amount of transmitted light 94 attenuates relative to the amount of light 91 emitted by the light source 10. On the other hand, due to factors such as 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 accurately detect dirt on the wall 22 from the transmitted light 94 alone.

[0029] The water quality analysis device 100 of this example detects the light source light amount, which is the amount of light 91 emitted by the light source 10, by the light source monitor 50. The light source monitor 50 detects the light source light amount of the light 91 before it enters the flow cell 20. The light source monitor 50 may receive branched light 93 obtained by branching a portion of the light 91.

[0030] The dirt detection unit 40 detects dirt on the wall 22 of the flow cell 20 based on the light source light amount and the transmitted light amount. The dirt detection unit 40 corrects the transmitted light amount with the light source light amount, and detects dirt on the wall 22 based on the correction result. For example, the dirt detection unit 40 corrects the transmitted light amount so that the smaller the light source light amount is, the larger the transmitted light amount is, and determines that the smaller the corrected transmitted light amount is, the larger the degree of dirt on the wall 22 is. As an example, the dirt detection unit 40 detects dirt on the wall 22 based on the light amount ratio between the light source light amount and the transmitted light amount (transmitted light amount / light source light amount). The dirt detection unit 40 determines that the smaller the light amount ratio is, the larger the degree of dirt is. In this way, by detecting dirt on the wall 22 using the light source light amount and the transmitted light amount, the influence of deterioration of the light source 10, etc. can be reduced, and dirt on the wall 22 can be detected with high accuracy. The light source light amount and the transmitted light amount may be measured in a state where the sample water is not flowed through the flow cell 20.

[0031] FIG. 2 is a diagram showing an example of the light source light amount, the transmitted light amount, and the light amount ratio (transmitted light amount / light source light amount). The vertical axis in FIG. 2 indicates the light amount or the light amount ratio. FIG. 2 also shows the light source light amount, the transmitted light amount, and the light amount ratio in a plurality of states A, B, C, and D. As an example, state A is a state at the time of shipment from the factory, in which the wall 22 is not dirty and the light source 10 is not deteriorated. State B is a state in which the wall 22 is dirty and the light source 10 is not deteriorated. State C is a state in which the wall 22 is not dirty and the light source 10 is deteriorated. State D is a state in which the wall 22 is dirty and the light source 10 is deteriorated. The degree of dirt on the wall 22 in states B and D is about the same, and the degree of deterioration of the light source 10 in states C and D is about the same.

[0032] 2 shows by dashed lines the judgment criteria when detecting the presence or absence of dirt on the wall 22 based only on the amount of transmitted light, and the judgment criteria when detecting the presence or absence of dirt on the wall 22 based on the light amount ratio (amount of transmitted light / amount of light source). The judgment criteria are set in advance by a user or the like. For example, if the light amount or the light amount ratio is greater than the judgment criteria, it is judged as "not dirty," and if the light amount or the light amount ratio is less than the judgment criteria, it is judged as "dirty."

[0033] If dirt on the wall 22 is detected based only on the amount of transmitted light, dirt in states B and D can be detected, but state C, where there is no dirt on the wall 22, may also be erroneously detected as "dirty." If only the amount of transmitted light is used, it is not possible to distinguish between a case where the amount of transmitted light is attenuated due to deterioration of the light source 10 and a case where the amount of transmitted light is attenuated due to dirt on the wall 22, and therefore dirt on the wall 22 will be erroneously detected when the light source 10 has deteriorated. Furthermore, even though the degree of dirt on the wall 22 is essentially the same in states B and D, the degree of dirt will be detected as different due to deterioration of the light source 10.

[0034] On the other hand, by using the light amount ratio (amount of transmitted light / amount of light source light), the influence of deterioration of the light source 10 can be reduced. For example, as in state C, dirt on the wall 22 can be detected with high accuracy by correcting the influence of deterioration of the light source 10. The dirt detection unit 40 may detect the presence or absence of dirt on the wall 22 by comparing the light amount ratio with a dirt determination criterion. The dirt detection unit 40 may determine the degree of dirt based on the magnitude of deviation between the light amount ratio and the dirt determination criterion.

[0035] 3 is a flowchart showing an example of the operation of the water quality analyzer 100. The water quality analyzer 100 starts measuring the concentration of a measurement target substance in a water sample in response to a predetermined trigger signal. The trigger signal may be input in response to an operation by a user or the like, may be input automatically in response to a change in the surrounding environment, may be input automatically every time a predetermined period of time has passed, or may be input in response to other factors.

[0036] In the measurement step S202, the concentration measurement unit 32 measures the water sample. The concentration measurement unit 32 measures the concentration of the measurement target substance 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 water sample. In this case, the concentration measurement unit 32 can measure the concentration of the fluorescent substance based on the amount of the measurement light 92.

[0037] In the continuous use step S204, the water quality analyzer 100 continuously or intermittently measures the concentration of the measurement target substance in the sample water for a preset continuous use period. After the continuous use period has elapsed, in the cleaning step S206, the cleaning unit 60 cleans the inside of the flow cell 20. The cleaning unit 60 may clean the flow cell 20 by flowing clean water or a cleaning solution containing a chemical or the like into the internal space 24 of the flow cell 20, or may clean the flow cell 20 by sweeping the internal space 24 with a member such as a brush, or may clean the flow cell 20 by a combination of these.

[0038] After the cleaning unit 60 performs a predetermined cleaning step, in a cleaning completion determination step S208, the dirt detection unit 40 determines whether or not cleaning of the flow cell 20 is completed. The dirt detection unit 40 may detect the presence or absence of dirt on the wall portion 22 of the flow cell 20, and may determine that cleaning is completed when it is determined that there is no dirt. As shown in FIG. 2, the dirt detection unit 40 may determine the presence or absence of dirt by comparing the light amount ratio (transmitted light amount / light source light amount) with a predetermined dirt determination standard. In the cleaning completion determination step S208, the transmitted light amount and the light source light amount may be measured in a state where the internal space 24 of the flow cell 20 is filled with clean water, or the transmitted light amount and the light source light amount may be measured in a state where the internal space 24 is not filled with liquid.

[0039] If it is determined in the cleaning completion determination step S208 that the cleaning is completed, the water quality analysis device 100 may repeat the process from the measurement step S202, or may end the operation. If it is determined in the cleaning completion determination step S208 that the cleaning is not completed, the cleaning unit 60 repeats the process of the cleaning step S206. If the cleaning is not completed within a set period from the start of cleaning of the flow cell 20, the dirt detection unit 40 may output a notification indicating that the cleaning is not completed. In this case, the water quality analysis device 100 may repeat the process from the measurement step S202, or may end 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 light amount and the transmitted light amount. The selection of the cleaning method may be the selection of the characteristics of the cleaning liquid used for cleaning, or the selection of the tool used for cleaning (whether to use a brush or a cleaning liquid, etc.). The cleaning unit 60 may select the cleaning method according to the degree of contamination determined from the light amount ratio (light source light 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 liquid to be passed 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 liquid 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 sample water 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 flowed in the continuous use stage 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 liquid may be selected according to the type of sample water. Since the substance of the dirt adhering to the flow cell 20 can be estimated according to the type of sample water, the cleaning unit 60 may select a cleaning liquid according to the type of sample water. The type of cleaning liquid to be selected for each substance may be preset for the cleaning unit 60. In the water quality analysis device 100 of this example, the part through which the cleaning liquid flows is preferably made of a material that does not deteriorate even when an acidic or alkaline cleaning liquid flows through it.

[0042] The cleaning unit 60 may estimate the type of substance adhering to the wall 22 based on the light amount ratio (light source light amount and transmitted light amount) at multiple wavelengths, and select a cleaning method according to the estimation result. The cleaning unit 60 may estimate the type of substance adhering to the wall 22 by comparing the shape of the spectrum of the light amount ratio with a transmission spectrum determined according to the type of each substance. By using the light amount ratio corrected for deterioration of the light source 10, the type of substance adhering to the wall 22 can be estimated with high accuracy.

[0043] Fig. 4 is a flowchart showing another operation example of the water quality analysis device 100. The operation of this example differs from the operation example of Fig. 3 in that it further includes a period elapse determination step S210 and a cleaning method change step S212. The other steps are the same as the example of Fig. 3.

[0044] In this example, if it is determined in the cleaning completion determination step S208 that the cleaning is not completed, the period elapse determination step S210 is performed. In the period elapse determination step S210, the dirt detection unit 40 determines whether or not a set period has elapsed since the start of cleaning of the flow cell 20. If the set period has not yet elapsed, the dirt detection unit 40 causes the cleaning unit 60 to repeat the process of the cleaning step S206. If the cleaning is not completed within the set period, the dirt detection unit 40 causes the cleaning unit 60 to change the cleaning method in the cleaning method change step S212. If the cleaning is not completed within the set period, the cleaning unit 60 may select a stronger cleaning method. For example, if the cleaning is not completed within the set period using fresh water, the cleaning unit 60 may perform cleaning again using a cleaning liquid containing a chemical or a surfactant. Also, the cleaning unit 60 may adjust the pH of the cleaning liquid if the cleaning is not completed within the set period using the cleaning liquid.

[0045] Fig. 5 is a flowchart showing another operation example of the water quality analysis device 100. The operation of this example differs from the operation example of Fig. 3 or Fig. 4 in that it further includes a dirt detection step S205. The other steps are similar to the example of Fig. 3 or Fig. 4. Fig. 5 shows an example in which the dirt detection step S205 is added to the operation example of Fig. 3, but the dirt detection step S205 may also be added to the operation example of Fig. 4.

[0046] The dirt detection unit 40 of this example detects dirt on the wall 22 using the amount of transmitted light when sample water is flowing through the flow cell 20. Specifically, the dirt on the wall 22 is detected using the amount of light from the light source and the amount of transmitted light measured during the continuous use period in the continuous use stage S204. The dirt detection unit 40 may detect dirt on the wall 22 at a predetermined cycle during the continuous use period. In the example of FIG. 5, dirt on the wall 22 is detected during the dirt detection stage S205 during the continuous use period. If it is determined that there is no dirt on the wall 22 during the dirt detection stage S205, the water quality analysis device 100 continues the process of the continuous use stage S204. If it is determined that there is dirt on the wall 22 during the dirt detection stage S205, the water quality analysis device 100 performs the process from the cleaning stage S206 onwards. The process from the cleaning stage S206 onwards is the same as the example of FIG. 3 or FIG. 4.

[0047] FIG. 6 is a diagram showing an example of the configuration of the measurement light detection unit 30 and the concentration measurement unit 32. The measurement light detection unit 30 of this 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. The water quality analysis device 100 of this example also 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, a part of the light 91-1 is emitted as scattered light, and the other part is emitted as transmitted light.

[0048] The water quality analyzer 100 of this example measures the concentration of fluorescent substances contained in the sample water based on the amount of fluorescent light (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 effects of light scattering and 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 referred to as turbidity) is high.

[0049] In order to improve the measurement accuracy of the fluorescence intensity, the water quality analysis device 100 of this example corrects the amount of measured measurement light 92-2 based on the turbidity of the sample water. 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 in the sample water is detected by the scattered light detection unit 31. The amount of transmitted light in the sample water may be detected by the transmitted light detection unit 70 shown in FIG. 1.

[0050] First, the measurement of the turbidity of the sample water will be described. The light source 10-1 irradiates the sample water inside the flow cell 20 with light 91-1, which is infrared light. 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 Figure 1) is generated. Scattered light is generated by light scattering at the suspended matter contained in the sample water. The higher the concentration of suspended matter, the greater the amount of scattered light. 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 amount of measurement light 92-1 detected by the scattered light detecting unit 31 and the amount of transmitted light 94 detected by the transmitted light detecting unit 70. The turbidity measuring unit 34 may measure the turbidity from the amount of one of the measurement light 92-1 and the transmitted light 94. As described above, the amount of measurement light 92-1 and the transmitted light 94 change depending on the turbidity, so the turbidity can be estimated from these amounts of light. The turbidity measuring unit 34 may calculate the turbidity using the ratio of the amount of measurement light 92-1 and the transmitted light 94 (amount of measurement light 92-1 / amount of transmitted light 94). The higher the turbidity, the higher the ratio of the amount of light.

[0053] Next, the measurement of the concentration of a fluorescent substance in the sample water will be described. The light source 10-2 irradiates the sample water inside the flow cell 20 with light 91-2. 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 therein. Since the light source 10-2 includes an optical filter, the light source 10-2 can irradiate the flow cell 20 with light in a predetermined wavelength range of the light 91-2. In this example, the substance to be measured is PAH. PAH emits fluorescence 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 light 91-2 onto the sample water inside the flow cell 20, fluorescence (measurement light 92-2) is generated. The fluorescence detection unit 33 detects the amount of measurement light 92-2. The fluorescence detection unit 33 may include an optical filter inside. Since it includes an optical filter, the fluorescence detection unit 33 can receive light in a predetermined wavelength range of the measurement light 92-2. In this example, the substance to be measured is PAH. When the wavelength of the excitation light for PAH is around 250 nm, the fluorescence wavelength is around 350 nm. Therefore, the transmission wavelength of the optical filter inside the fluorescence detection unit 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 the fluorescent substance contained in the sample water from the amount of measurement light 92-2 detected by the fluorescence detection unit 33. As described above, the amount of measurement light 92-2 attenuates depending on the turbidity of the sample water. The signal processing unit 35 corrects the amount of measurement light 92-2 based on the turbidity measured by the turbidity measurement unit 34 to calculate the concentration of the fluorescent substance. The relationship between the turbidity and the amount of correction may be experimentally determined in advance and set in the signal processing unit 35. Through such processing, the water quality analysis device 100 can accurately measure the concentration of the fluorescent substance in the sample water.

[0057] 5, when detecting contamination on the wall 22 using the amount of transmitted light while 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, which may result in a deterioration in the accuracy of detecting contamination on the wall 22.

[0058] The dirt detection unit 40 may detect dirt on the wall 22 of the flow cell 20 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 from the light source. The dirt detection unit 40 may use the amount of transmitted light common to turbidity measurement. The dirt detection unit 40 may use the turbidity calculated by the turbidity measurement unit 34 instead of the amount of scattered light. The dirt detection unit 40 may correct the amount of transmitted light using the amount of scattered light. In other words, when the amount of scattered light is large, it is considered that the amount of transmitted light is greatly attenuated by suspended matter, so the amount of transmitted light may be corrected to a larger value as the amount of scattered light increases. This reduces the effect of turbidity of the sample water and allows dirt on the wall 22 to be detected with high accuracy.

[0059] In another example, the dirt detection unit 40 may determine whether the wall 22 is dirty, provided that the amount of scattered light or turbidity is equal to or less than a reference value. In other words, the dirt detection unit 40 may determine whether the wall 22 is dirty, provided that the attenuation of the amount of transmitted light by the sample water is small. This reduces the effect of the turbidity of the sample water, and enables the dirt on the wall 22 to be detected with high accuracy.

[0060] In the example of Fig. 6, the amount of transmitted light used to measure turbidity and the amount of transmitted light used to measure dirt can be detected by a common transmitted light detector 70. measurement Therefore, the number of components of the water quality analyzer 100 can be reduced.

[0061] 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 claims that such modifications and improvements can also be included in the technical scope of the present invention.

[0062] It should be noted that the order of execution of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically indicated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]

[0063] 10 light source, 20 flow cell, 22 wall, 24 internal space, 30 measurement light detection section, 31 scattered light detection section, 32 concentration measurement section, 33 fluorescence detection section, 34 turbidity measurement section, 35 signal processing section, 40 dirt detection section, 50 light source monitor, 60 cleaning section, 70 transmitted light detection section, 91 light, 92 measurement light, 93 branched light, 94 transmitted light, 100 water quality analysis device

Claims

1. A water quality analyzer for measuring a concentration of a measurement target substance contained in a sample water, comprising: a flow cell having a light-transmitting wall and an internal space surrounded by the wall, the sample water passing through the internal space; A light source that irradiates light toward the flow cell; a light source monitor for detecting a light source amount, which is an amount of light emitted by the light source; a transmitted light detector for detecting an amount of transmitted light, which is an amount of light transmitted through the flow cell; a dirt detection unit that detects dirt on the wall portion of the flow cell based on the light source light amount and the transmitted light amount; a cleaning unit that cleans dirt from the wall portion of the flow cell; a scattered light detection unit for detecting an amount of scattered light, which is an amount of light scattered from the sample water; Equipped with the dirt detection unit detects dirt on the wall portion by using the amount of transmitted light in a state in which the sample water is flowing through the flow cell; the cleaning unit starts cleaning the flow cell when the wall portion is dirty, The dirt detection unit detects dirt on the wall of the flow cell on 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 equal to or lower than a reference value. Water quality analyzer.

2. A water quality analyzer for measuring the concentration of a target substance contained in sample water, comprising: a flow cell having a light-transmitting wall and an internal space surrounded by the wall, the sample water passing through the internal space; A light source that irradiates light toward the flow cell; a light source monitor for detecting a light source amount, which is an amount of light emitted by the light source; a transmitted light detector for detecting an amount of transmitted light, which is an amount of light transmitted through the flow cell; a dirt detection unit that detects dirt on the wall portion of the flow cell based on the light source light amount and the transmitted light amount; a cleaning unit that cleans dirt from the wall portion of the flow cell; a scattered light detection unit for detecting an amount of scattered light, which is an amount of light scattered from the water sample; Equipped with the contamination detection unit corrects the amount of transmitted light in a state in which the sample water is flowing through the flow cell using the amount of scattered light, and detects contamination on the wall portion of the flow cell based on the amount of light from the light source and the corrected amount of transmitted light; The cleaning unit starts cleaning the flow cell when the wall portion is dirty. Water quality analyzer.

3. A water quality analyzer for measuring a concentration of a measurement target substance contained in a sample water, comprising: a flow cell having a light-transmitting wall and an internal space surrounded by the wall, the sample water passing through the internal space; A light source that irradiates light toward the flow cell; a light source monitor for detecting a light source amount, which is an amount of light emitted by the light source; a transmitted light detector for detecting an amount of transmitted light, which is an amount of light transmitted through the flow cell; a dirt detection unit that detects dirt on the wall portion of the flow cell based on the light source light amount and the transmitted light amount; Equipped with the dirt detection unit detects dirt on the wall portion by using the amount of transmitted light in a state in which the sample water is flowing through the flow cell; a scattered light detection unit for detecting an amount of scattered light, which is an amount of light scattered from the water sample; 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 detecting unit and the amount of transmitted light detected by the transmitted light detecting unit; Further comprising: The dirt detection unit detects dirt on the wall of the flow cell on the condition that the turbidity of the sample water is equal to or lower than a reference value. Water quality analyzer.

4. The dirt detection unit detects dirt on the wall portion based on a ratio between the amount of light from the light source and the amount of transmitted light. The water quality analysis device according to any one of claims 1 to 3.

5. The dirt detection unit determines whether or not 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 of the flow cell. The water quality analysis device according to claim 2 .

6. The dirt detection unit outputs a notification indicating that cleaning is not completed when cleaning of the flow cell is not completed within a set period from the start of cleaning of the flow cell. The water quality analysis device according to claim 5.

7. The dirt detection unit changes a cleaning method in the cleaning unit when cleaning of the flow cell is not completed within a set period from the start of cleaning of the flow cell. The water quality analysis device according to claim 5.

8. The cleaning unit selects a cleaning method for the flow cell based on at least one of the amount of light from the light source and the amount of transmitted light. The water quality analysis device according to claim 5.

9. The cleaning unit adjusts a pH of a cleaning solution to be flowed through the flow cell based on a ratio between the amount of light from the light source and the amount of transmitted light. The water quality analysis device according to claim 8.

10. The cleaning unit selects a cleaning method for the flow cell based on the type of the sample water that has been flowed through the flow cell in the past. The water quality analysis device according to claim 5.

Images