Water quality measuring device and measuring method

Abstract

This application discloses a water quality measuring device and method, belonging to the field of analytical testing technology. The water quality measuring device includes a light source, a first signal receiver, and a buffer tank. The buffer tank has an inlet and an outlet. The inlet is used to continuously input the sample to be tested, and the outlet is used to continuously output the sample to be tested, forming a stable liquid column from the water flow at the outlet of the buffer tank. The light source is positioned on the first side of the liquid column, and the first signal receiver is positioned on the second side. The light emitted by the light source passes through the liquid column and is received by the first signal receiver, which measures the intensity of the received light. This non-contact method tests the analyte in the water sample. The light emitted by the light source passes through the liquid column, and the change in signal is detected by the first signal receiver, which can be converted into the content / value of the analyte in the water sample. This method can meet the requirements of long-term reliable, accurate, and stable water quality testing in various scenarios, solving a key technical problem that urgently needs to be overcome in the current field of water quality monitoring.

Description

Technical Field

[0001] This application relates to the field of analytical testing technology, and in particular, to a water quality measuring device. Furthermore, this application also relates to a measuring method including the aforementioned water quality measuring device. Background Technology

[0002] In the field of water quality measurement technology, optical water quality detection has become one of the mainstream technologies for online water quality monitoring due to its advantages such as no need for human intervention and strong anti-interference ability.

[0003] Taking pH detection as an example, current mainstream analytical methods can be divided into three main categories: electrochemical methods, chemical indicator methods, and optical methods. These methods are based on different principles and have their own characteristics in terms of response speed, maintenance cost, and environmental adaptability, making them suitable for different scenarios. Among them, the electrochemical method uses a glass electrode as the indicator electrode, combined with a reference electrode to form a galvanic cell system. The glass membrane of the glass electrode (such as silicate glass) has a selective response to hydrogen ions. The potential difference generated across the membrane due to the difference in hydrogen ion activity follows the Nernst equation, thus obtaining the pH value. This method has advantages such as high sensitivity, wide measurement range, and fast response, but it also has significant limitations: the glass membrane has low mechanical strength and is easily damaged, requiring regular calibration; it is prone to sodium error (sodium ion interference) in strongly alkaline environments (pH>12); and it has poor adaptability to organic solvents or high-concentration electrolytes. The chemical indicator method uses the color change of acid-base indicators (such as phenolphthalein, litmus, and methyl orange) within a specific pH range to determine pH. The pH-based method, while simple and low-cost, suffers from low accuracy and subjectivity, making it primarily suitable for imprecise measurements like rapid screening with test strips. The optical method, on the other hand, measures pH based on the changes in the spectral characteristics (including color, absorbance, and fluorescence intensity) of pH-sensitive substances (such as fluorescent dyes and optical probes) under different pH conditions. Its core principle utilizes the protonation / deprotonation reactions of pH-sensitive dyes (such as bromocresol green and phenol red) under different pH conditions, leading to changes in molecular structure and consequently, significant changes in the maximum absorption wavelength or absorbance. The biggest advantage of this method is that it eliminates the need for electrodes to contact the test solution, making it particularly suitable for monitoring toxic and corrosive solutions, and enabling remote continuous monitoring. However, it's crucial to note that the cleanliness of the optical detection window directly affects the light transmission effect and must be kept clean and uncontaminated.

[0004] In tap water treatment, sewage pipe network operation and maintenance, and water environment management, pH (acidity / alkalinity) monitoring is a core indicator of water quality analysis. Its monitoring data directly affects key aspects such as water treatment process optimization, pipe network safety maintenance, sewage treatment efficiency improvement, and environmental risk early warning. The currently widely used glass electrode method faces significant challenges:

[0005] 1. Wastewater has a complex composition and is not a simple, stable solution. The mud, grease and other substances it contains can easily form an adhesion layer on the surface of the pH electrode sensitive membrane (such as a glass membrane). After blocking the membrane pores, it will hinder the effective contact between hydrogen ions and the electrode, resulting in response delay or reading drift.

[0006] 2. Long-term operation in a relatively clean tap water environment can lead to the deposition of minerals and organic matter on the membrane surface, causing electrode contamination or scaling. This can result in decreased measurement accuracy and affect the reliability of monitoring data, potentially causing a chain reaction: decreased coagulation efficiency → incomplete disinfection → substandard effluent.

[0007] 3. Electrodes need to be calibrated regularly to maintain measurement accuracy, and their service life is usually only 6 months. As consumables, they need to be replaced frequently, which not only leads to high operating costs, but also makes manual calibration operations complicated and difficult to achieve periodic standardized calibration management.

[0008] Therefore, there is an urgent need for a water quality measurement device to solve the above problems and achieve long-term stable monitoring and accurate measurement of water quality parameters. Summary of the Invention

[0009] In view of at least one of the above technical problems, this application provides a water quality measuring device that can form a "liquid column" of the sample under gravity and constant pressure in a non-contact manner. The light emitted by the light source passes through the "liquid column", and the change of the signal is detected by the first signal receiver. The result can be converted into the content / value of the sample's analyte. This device can meet the requirements of long-term reliable, accurate and stable monitoring in various scenarios and solves the key technical problems that urgently need to be solved in the current water quality monitoring field.

[0010] This application also provides a water quality measurement method using the above-mentioned water quality measuring device.

[0011] According to one aspect of this application, a water quality measuring device is provided, comprising a light source, a first signal receiver, and a buffer tank;

[0012] The buffer tank has an inlet and an outlet. The inlet is used to continuously input the sample to be tested, while the outlet is used to continuously output the sample to be tested, so as to keep the liquid level in the buffer tank stable and to make the water flow at the outlet of the buffer tank form a stable liquid column. The light source is set on the first side of the liquid column, and the first signal receiver is set on the second side of the liquid column. The light emitted by the light source passes through the liquid column and is received by the first signal receiver. The first signal receiver is used to measure the light intensity of the received light.

[0013] In some embodiments of this application, the mass measurement device further includes a beam splitter and a second signal receiver. The beam splitter and the second signal receiver are disposed on the first side of the liquid column, and the beam splitter is located between the light source and the liquid column. The beam splitter is used to transmit a portion of the light emitted by the light source through the liquid column and be received by the first signal receiver, while reflecting another portion of the light emitted by the light source to the second signal receiver for reception.

[0014] In some embodiments of this application, the water quality measuring device further includes a first optical focusing component, a second optical focusing component, and a third optical focusing component. The first and third optical focusing components are disposed on opposite sides of the liquid column. The light emitted by the light source is focused by the first optical focusing component, passes through the liquid column, is focused by the third optical focusing component, and is then transmitted to the first signal receiver. The second optical focusing component is disposed between the second signal receiver and the beam splitter. The second optical focusing component is used to focus the light reflected by the beam splitter and transmit it to the second signal receiver.

[0015] In some embodiments of this application, the water quality measuring device further includes an inlet pipe and an overflow pipe. The inlet pipe is connected to the inlet of the buffer tank and is equipped with an inlet pump. The overflow pipe is connected to a pre-set overflow port on the side wall of the buffer tank.

[0016] According to another aspect of this application, a water quality measurement method is also provided, which employs the above-mentioned water quality measurement device, and the water quality measurement method includes the following steps:

[0017] S100: The sample to be tested is continuously input through the inlet of the buffer tank and continuously output through the outlet of the buffer tank to keep the liquid level in the buffer tank stable and to make the water flow at the outlet of the buffer tank form a stable liquid column. The light emitted by the light source passes through the liquid column and is received by the first signal receiver to obtain the real-time transmitted light intensity I of the sample to be tested.

[0018] S200: Absorbance A is calculated using the following formula:

[0019] A = lg(I0 / I) 1

[0020] In the formula, I0 is the incident light intensity, and I is the transmitted light intensity obtained in real time by the first signal receiver when the liquid column contains the sample to be tested.

[0021] S300: Calculate the content / value of the parameter to be measured in the water sample based on the absorbance A of the parameter to be measured in the water sample.

[0022] In some embodiments of this application, before step S100, a standard working curve calibration of the parameter to be tested is performed: various standard samples of the parameter to be tested with known content / values ​​are prepared; standard samples of different content / values ​​are continuously input through the inlet of the buffer tank; standard samples of different content / values ​​are continuously output from the outlet of the buffer tank to keep the liquid level in the buffer tank stable and to form a stable liquid column from the outlet of the buffer tank; the absorbance A of each standard sample is measured and calculated; the content / value of each standard sample is fitted one-to-one with the absorbance A to obtain the standard working curve of the parameter to be tested, and the linear function equation of the standard working curve is obtained.

[0023] A = a * C + M 2

[0024] In the formula, a is a proportionality constant, C represents the content / value of the parameter to be measured, and M is a constant.

[0025] In some embodiments of this application, before step S100, the incident light intensity I0 of the parameter to be measured in the water sample is obtained: pure water is continuously input through the inlet of the buffer tank and pure water is continuously output through the outlet of the buffer tank to keep the liquid level in the buffer tank stable and to make the water flow at the outlet of the buffer tank form a stable liquid column. The light emitted by the light source passes through the liquid column and is received by the first signal receiver to obtain the incident light intensity I0.

[0026] In some embodiments of this application, a beam splitter and a second signal receiver are disposed on the first side of the liquid column, and the beam splitter is located between the light source and the liquid column. The beam splitter is used to transmit a portion of the light emitted by the light source through the liquid column and be received by the first signal receiver, while reflecting the other portion of the light to the second signal receiver for reception. During the process of acquiring the incident light intensity I0 of the parameter to be measured in the water sample, the initial value K of the light intensity received by the second signal receiver is recorded. When the sample to be measured is measured, the light intensity value Kn received by the second signal receiver is recorded for each water sample measurement. The ratio of Kn / K is calculated as the I0 variation coefficient, and the following formula is obtained by combining with Formula 1:

[0027] A = lg[I] 0* K n / K) / I] 3

[0028] In some embodiments of this application, before step S300, the method further includes: obtaining a turbidity or color curve of the water sample;

[0029] By changing the incident wavelength of the light source and recording the different absorbance values ​​of the same sample at different wavelengths, the wavelength-absorbance absorption spectrum curve of the sample is obtained through fitting. Points where the measured parameter does not absorb are selected on the wavelength-absorbance absorption spectrum of the sample, and turbidity or colorimetric curves are obtained through fitting. This can be expressed by a linear function formula:

[0030] A L2 =F*X+B 4

[0031] In the formula, A L2 The absorbance represents the turbidity or chromaticity, where X represents the incident wavelength of the light source in nm, F is a proportionality constant, and B is a constant.

[0032] At the same wavelength, the absorbance A corresponding to the wavelength-absorbance absorption spectrum curve of the sample under test. L1 The absorbance A obtained by subtracting the wavelength-absorbance absorption spectrum curve of turbidity or chromaticity in Formula 4 is... L2 The true absorbance A of the parameter to be measured in the water sample was obtained. L3 , will A L3 Substitute the values ​​into step S300 to calculate the water quality measurement values ​​after eliminating turbidity and / or color interference.

[0033] In some embodiments of this application, a window is provided next to the liquid column, and the window is heated to a preset temperature to avoid the generation of water mist.

[0034] This application has the following beneficial effects:

[0035] This application discloses a water quality measuring device with an inlet and an outlet in a buffer tank. The sample to be tested is continuously input through the inlet and continuously output through the outlet, maintaining a stable liquid level in the buffer tank and forming a stable liquid column at the outlet. Light emitted from a light source passes through the liquid column and is received by a first signal receiver. The intensity of the emitted light is obtained, and the corresponding absorbance value can be calculated, thus determining the content / value of the analyte in the water sample. In this water quality measuring device, the sample to be tested forms a stable liquid column under gravity and constant pressure. The light source and the first signal receiver are located on opposite sides of the liquid column. Light emitted from the light source passes through the liquid column and is received by the first signal receiver. By detecting changes in the light signal, the content / value of the analyte in the water sample can be calculated. During this measurement process, the sample does not need to contact the detection window, avoiding contamination of the detection window. This application provides a water quality measuring device that can meet the needs of various scenarios with long-term reliability, accuracy, and stability, solving a key technical problem that urgently needs to be overcome in the current water quality monitoring field.

[0036] The water quality measurement method of this application also possesses the aforementioned beneficial effects. It employs a non-contact + optical method to detect the content / value of the analyte in a water sample. Under the influence of gravity and constant pressure, the sample forms a stable liquid column. The light source and the first signal receiver are located on opposite sides of the liquid column. The light emitted by the light source passes through the liquid column and is received by the first signal receiver. By detecting changes in the light signal, the content / value of the analyte in the water sample can be calculated. The overall operation of this method is more streamlined and efficient, and the sample does not need to contact the detection window, avoiding contamination of the detection window by the sample. This enables long-term, reliable, accurate, and stable monitoring of the analyte in the water sample.

[0037] In obtaining the incident light intensity I0 for the detection of the parameter to be measured in a water sample, a liquid column is formed using pure water. The light emitted by the light source passes through the liquid column and is received by the first signal receiver, thus obtaining the incident light intensity I0, which can improve the accuracy of detection. During the detection stage, the transmitted light intensity I of the sample to be measured is detected in real time by the first signal receiver, and the absorbance A can be calculated using the formula, thereby calculating the content / value of the parameter to be measured in the water sample after light source attenuation compensation.

[0038] This application addresses the shortcomings of electrode methods in practical applications, such as the need for regular calibration and the potential impact of substances like grease and particles in water samples on the accuracy of electrode method detection. Furthermore, the sample to be tested in this application does not need to contact the detection window, avoiding the need for regular cleaning / replacement of cuvettes / detection cells in existing optical water quality detection methods, thus reducing maintenance and operating costs.

[0039] Of course, any product implementing this application does not necessarily need to achieve all the advantages described above simultaneously. In addition to the purposes, features, and advantages described above, this application also has other purposes, features, and advantages. The following will provide a more detailed description of this application with reference to figures. Attached Figure Description

[0040] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0041] Figure 1 This is a schematic diagram of the overall structure of the water quality measuring device according to a preferred embodiment of this application;

[0042] Figure 2 This is a graph showing the relationship between absorbance and wavelength in a preferred embodiment of this application;

[0043] Figure 3 This is a pH standard working curve obtained by fitting various pH standard solutions according to a preferred embodiment of this application.

[0044] Legend: 1. Light source; 2. Spectrometer; 3. First optical focusing assembly; 4. Liquid column; 5. First signal receiver; 6. Second signal receiver; 7. Window; 8. Second optical focusing assembly; 9. Inlet pump; 10. Buffer tank; 11. Detection reagent; 12. Inlet pipe; 13. Overflow pipe; 14. Third optical focusing assembly. Detailed Implementation

[0045] The embodiments of this application are described in detail below with reference to the accompanying drawings; however, this application may be implemented in a variety of different ways as defined and covered below.

[0046] Figure 1 This is a schematic diagram of the overall structure of the water quality measuring device according to a preferred embodiment of this application; Figure 2 This is a graph showing the relationship between absorbance and wavelength in a preferred embodiment of this application; Figure 3 This is a pH standard working curve obtained by fitting various pH standard solutions according to a preferred embodiment of this application.

[0047] like Figure 1 As shown, a water quality measuring device according to this embodiment includes a light source 1, a first signal receiver 5, and a buffer tank 10;

[0048] The buffer tank 10 has an inlet and an outlet. The inlet of the buffer tank 10 is used to continuously input the sample to be tested, and the outlet is used to continuously output the sample to be tested, so that the liquid level in the buffer tank 10 is kept stable and the water flow at the outlet of the buffer tank 10 forms a stable liquid column 4. The light source 1 is set on the first side of the liquid column 4, and the first signal receiver 5 is set on the second side of the liquid column 4. The light emitted by the light source 1 passes through the liquid column 4 and is received by the first signal receiver 5. The first signal receiver 5 is used to measure the light intensity of the received light.

[0049] The water quality measuring device of this application has an inlet and an outlet on a buffer tank 10. The sample to be tested is continuously input through the inlet and continuously output through the outlet, thus maintaining a stable liquid level in the buffer tank 10 and forming a stable liquid column 4 at the outlet. Light emitted by a light source 1 passes through the liquid column 4 and is received by a first signal receiver 5. By measuring the intensity of the received light by the first signal receiver 5, the corresponding absorbance value can be calculated, thereby obtaining the content / value of the parameter to be tested in the water sample. In this water quality measuring device, the sample to be tested forms a stable liquid column 4 under the action of gravity and constant pressure. The light source 1 and the first signal receiver 5 are located on opposite sides of the liquid column 4. The light emitted by the light source passes through the liquid column 4 and is received by the first signal receiver 5. By detecting the change in the light signal, the content / value of the parameter to be tested in the water sample can be calculated. During this measurement process, the sample to be tested does not need to contact the detection window, avoiding contamination of the detection window by the sample. This application provides a water quality measurement device that can meet the needs of various scenarios for long-term reliability, accuracy and stability, and solves the key technical problems that urgently need to be solved in the current water quality monitoring field.

[0050] It is understood that the sample to be tested is either a water sample or a combination of a water sample and a test reagent 11. When the sample to be tested is a water sample and a test reagent, the water sample and the test reagent can be mixed in the buffer tank, or they can be mixed and then introduced into the buffer tank.

[0051] Preferably, please refer to Figure 1 As shown, the water quality measuring device also includes a beam splitter 2 and a second signal receiver 6. The beam splitter 2 and the second signal receiver 6 are disposed on the first side of the liquid column 4, and the beam splitter 2 is located between the light source 1 and the liquid column 4. The beam splitter 2 is used to transmit a portion of the light emitted by the light source 1 through the liquid column 4 and be received by the first signal receiver 5, while reflecting another portion of the light emitted by the light source 1 to the second signal receiver 6 and being received by the second signal receiver 6.

[0052] Here, "beam splitter 2" refers to an optical element in the prior art, a special lens that can simultaneously reflect light and allow light to pass through. In some embodiments, the beam splitter 2 is a semi-reflective mirror, which is usually composed of an optical glass substrate coated with a semi-reflective film. Optionally, the semi-reflective mirror 2 is set at a preset angle with the vertical liquid column 4. The second signal receiver 6 is set in the reflected light path of the semi-reflective mirror 2 to receive the reflected light from the semi-reflective mirror 2.

[0053] By setting up a beam splitter 2 and a second signal receiver 6 to construct a reference detection optical path for the light source 1, it can be used to detect the dynamic changes in the intensity of the emitted light source in real time, thereby effectively compensating for the detection error caused by the attenuation of the light source 1 and significantly improving the long-term stability and data reliability of the device.

[0054] Preferably, please refer to Figure 1 As shown, the water quality measuring device also includes a window 7, which is positioned next to the liquid column 4.

[0055] Understandably, to improve the stability of the liquid column 4, a window 7 is placed next to the liquid column 4 to reduce the influence of external environmental factors on the liquid column 4, such as reducing the influence of airflow on the liquid column 4. Optionally, the window 7 is an integrated heating window; heating the window to a preset temperature can effectively suppress the formation of water mist and reduce the interference of water mist on the detection optical path. Optionally, the window 7 is a glass plate made of sapphire, which has strong thermal stability and corrosion resistance, and can effectively prevent water vapor from the sample from corroding the surface of the window.

[0056] Preferably, please refer to Figure 1 As shown, the water quality measuring device also includes a first optical focusing component 3, a second optical focusing component 8, and a third optical focusing component 14. The first optical focusing component 3 and the third optical focusing component 14 are arranged on opposite sides of the liquid column 4. The light emitted by the light source 1 is focused by the first optical focusing component 3, passes through the liquid column 4, is focused by the third optical focusing component 14, and is then transmitted to the first signal receiver 5. The second optical focusing component 8 is arranged between the second signal receiver 6 and the beam splitter 2. The second optical focusing component 8 is used to focus the light reflected by the beam splitter 2 and transmit it to the second signal receiver 6.

[0057] It is understandable that the first optical focusing component 3, the second optical focusing component 8, and the third optical focusing component 14 are all light-focusing lenses. The first optical focusing component 3 effectively focuses the light, which then passes through the liquid column 4 in a very small spot. The light is then refocused by the second optical focusing component 8 and received by the first signal receiver 5. The third optical focusing component 14 focuses the light reflected from the semi-transparent mirror 2 and transmits it to the second signal receiver 6. This configuration helps to enhance the light signal intensity and improve the sensitivity of the first and second signal receivers 5 and 6.

[0058] Preferably, please refer to Figure 1 As shown, the water quality measuring device also includes an inlet pipe 12 and an overflow pipe 13. The inlet pipe 12 is connected to the inlet of the buffer tank 10, and an inlet pump 9 is installed on the inlet pipe 12. The overflow pipe 13 is connected to the overflow port preset on the side wall of the buffer tank 10.

[0059] Understandably, the sample to be tested enters the buffer tank 10 under pressure via the inlet pump 9, and flows out by siphon. The liquid level in the buffer tank 10 remains stable due to the continuous replenishment of the sample by the inlet pump 9. At this time, the water flowing out of the outlet by siphon can be regarded as free outflow from the orifice under a constant head. If the buffer tank 10 is connected to tap water, since tap water itself is pressurized, there is no need to use the inlet pump 9 for pressurization, thereby reducing energy consumption.

[0060] According to another aspect of this application, a water quality measurement method is also provided, which employs the above-mentioned water quality measurement device, and the water quality measurement method includes the following steps:

[0061] S100: The sample to be tested is continuously input through the inlet of the buffer tank 10 and continuously output through the outlet of the buffer tank 10 to keep the liquid level in the buffer tank 10 stable and to make the water flow at the outlet of the buffer tank 10 form a stable liquid column 4. The light emitted by the light source 1 passes through the liquid column 4 and is received by the first signal receiver 5 to obtain the real-time transmitted light intensity I of the sample to be tested.

[0062] S200: Absorbance A is calculated using the following formula:

[0063] A = lg(I0 / I) 1

[0064] In the formula, I0 is the incident light intensity, and I is the transmitted light intensity obtained in real time by the first signal receiver 5 when the liquid column 4 contains the sample to be tested.

[0065] S300: Based on the absorbance A of the parameter to be measured in the water sample, the content / value of the parameter to be measured in the water sample is calculated by combining the standard working curve of absorbance-concentration of the parameter to be measured.

[0066] It should be noted that the turbidity of wastewater is usually defined as the degree to which water contains mud, silt, or fine organic matter, causing the water to become cloudy. The unit of turbidity is usually NTU (scattered turbidity), and turbidity can be measured using a turbidimeter. On the other hand, the color of wastewater refers to the intensity of the color that water exhibits due to the presence of colored substances, and it is usually measured using colorimetric methods or dilution methods.

[0067] Preferably, the water quality measurement method includes the following steps: before step S100, standard working curve calibration of the parameter to be measured is performed:

[0068] Prepare various standard samples with known content / values ​​for the analyte parameters. Continuously input standard samples with different content / values ​​into the inlet of buffer tank 10, and continuously output standard samples with different content / values ​​from the outlet of buffer tank 10 to maintain a stable liquid level within buffer tank 10 and to form a stable liquid column 4 at the outlet of buffer tank 10. Measure and calculate the absorbance A of each standard sample. Fit the content / value of each standard sample to the absorbance A to obtain a standard working curve for the analyte parameter, and obtain the linear function equation of the standard working curve:

[0069] A = a * C + M 2 where a is a proportionality constant, C represents the content / value of the parameter to be measured, and M is a constant.

[0070] Substitute the absorbance A calculated by Formula 1 into Formula 2 to calculate the content / value of the parameter to be measured in the water sample.

[0071] It is understood that the standard sample to be tested is either the standard solution to be tested, or the standard sample to be tested is a standard solution to be tested and the test reagent 11. When the standard sample to be tested is a standard solution to be tested and the test reagent 11, the standard solution to be tested and the test reagent 11 can be mixed in the buffer tank, or they can be mixed and then added to the buffer tank.

[0072] It should be noted that the calibration of the standard working curve for the parameter to be tested is completed before the water sample test. Furthermore, the standard working curve does not need to be recalibrated for every water sample test; recalibration is only required when there are significant changes in the testing environment or abnormal test results, in order to ensure the accuracy of the test.

[0073] In some embodiments, the standard working curve calibration of pH is taken as an example:

[0074] Prepare a series of standard solutions with known pH values; add detection reagent 11 (identical to the detection reagent 11 used for measuring water samples) to each standard solution to obtain the standard samples to be tested. Continuously input the standard samples to be tested with different pH values ​​through the inlet of buffer tank 10, and continuously output the standard samples to be tested with different pH values ​​through the outlet of buffer tank 10 to maintain a stable liquid level in buffer tank 10 and to form a stable liquid column 4 at the outlet of buffer tank 10. Fit the content / value of each standard sample to the absorbance A to obtain a pH standard working curve, thus obtaining the standard working curve equation. Please refer to [reference needed]. Figure 3 As shown; measure the absorbance A of pH in the water sample, substitute it into the linear function equation of the pH standard working curve, and the pH value of the water sample can be obtained.

[0075] Please refer to Table 1 below. Table 1 shows the absorbance A of each pH standard solution with pH values ​​of 4.92, 5.91, 6.81, 7.73, and 8.34, measured at a wavelength of 550 nm.550nm The pH value of each pH standard solution was fitted one-to-one with the absorbance A to obtain the pH standard working curve, and the equation of the standard working curve was obtained as A = -0.64555 + 0.13868 * pH.

[0076] Table 1. Absorbance of pH standard solutions with different known pH values.

[0077]

[0078] Preferably, before step S100, the incident light intensity I0 of the parameter to be measured in the water sample is obtained by continuously inputting pure water through the inlet of the buffer tank 10 and continuously outputting pure water through the outlet of the buffer tank 10 to keep the liquid level in the buffer tank 10 stable and to make the water flow at the outlet of the buffer tank 10 form a stable liquid column 4. The light emitted by the light source 1 passes through the liquid column 4 and is received by the first signal receiver 5 to obtain the incident light intensity I0.

[0079] This application's water quality measurement method employs a non-contact + optical method to measure the content / value of the analyte in a water sample. During the measurement process, the sample does not need to contact the detection window, avoiding contamination of the detection window by the sample. It can meet the requirements of long-term reliable, accurate, and stable water quality measurement in various scenarios. The sample forms a liquid column 4 under gravity and constant pressure. The light source 1 and the first signal receiver 5 are located on opposite sides of the liquid column 4. The light emitted by the light source passes through the liquid column 4 and is received by the first signal receiver 5. By detecting the change in the light signal, the content / value of the analyte in the water sample can be calculated. To obtain the incident light intensity I0 for the analyte detection in the water sample, pure water forms the liquid column 4. The light emitted by the light source passes through the liquid column and is received by the first signal receiver 5, thus obtaining the incident light intensity I0, which improves the accuracy of the detection. During the detection stage, the transmitted light intensity I of the sample is detected in real time by the first signal receiver 5. The absorbance A of the sample can then be calculated using formula 1, thereby calculating the content / value of the analyte in the water sample. The method described in this application is more streamlined and efficient in its overall operation, and the sample to be tested does not need to come into contact with the detection window, thus avoiding contamination of the detection window by the sample. It can achieve long-term, reliable, accurate and stable monitoring of the parameters to be tested in water samples.

[0080] This application addresses the shortcomings of electrode methods in practical applications, such as the need for regular calibration and the potential impact of substances like grease and particles in water samples on the accuracy of electrode detection. Furthermore, the method described in this application eliminates the need for the sample to come into contact with the detection window, avoiding the need for regular cleaning and replacement of cuvettes / detection cells in existing optical water quality detection methods, thus reducing maintenance requirements.

[0081] Preferably, a beam splitter 2 and a second signal receiver 6 are disposed on the first side of the liquid column 4, and the beam splitter 2 is located between the light source 1 and the liquid column 4. The beam splitter 2 is used to transmit a portion of the light emitted by the light source 1 through the liquid column 4 and be received by the first signal receiver 5, while reflecting the other portion of the light to the second signal receiver 6 for reception. During the process of acquiring the incident light intensity I0 of the parameter to be measured in the water sample, the initial value K of the light intensity received by the second signal receiver 6 is recorded. During water sample measurement, the value K of the light intensity received by the second signal receiver 6 at each water sample measurement is recorded. n Calculate K n The ratio of / K is used as the coefficient of change of I0. Combined with Formula 1, we get the following formula:

[0082] A = lg[I] 0* K n / K) / I] 3

[0083] It should be noted that changes in the light source will affect the I0 value. The intensity of the reflected light received by the second signal receiver 6 should be recorded in each measurement. During the process of acquiring the incident light intensity I0 of the parameter to be measured in the water sample, the initial value K of the light intensity received by the second signal receiver 6 should be recorded. During each water sample measurement, the light intensity value K received by the second signal receiver 6 should be recorded. n The ratio of Kn / K is calculated as the coefficient of I0 variation, which expands Formula 1 to Formula 3, thereby improving the accuracy of absorbance calculation for the measured parameter in the water sample. By setting up the spectrophotometer 2 and the second signal receiver 6 to construct the control detection optical path for the light source 1, it can be used to detect the dynamic changes in the emitted light intensity in real time, thereby effectively compensating for the detection error caused by the attenuation of the light source 1 and significantly improving the long-term stability and data reliability of the device.

[0084] Preferably, before step S300, the method further includes: obtaining a turbidity or color curve of the water sample;

[0085] By changing the incident wavelength of light source 1, the absorbance of the same sample at different wavelengths is recorded. The wavelength-absorbance absorption spectrum curve of the sample is then fitted. Points where the measured parameter does not absorb are selected on the wavelength-absorbance absorption spectrum of the sample, and the turbidity or colorimetric curve is fitted. This can be expressed by a linear function formula:

[0086] A L2 =F*X+B 4

[0087] In the formula, A L2 The absorbance corresponding to turbidity or chromaticity is represented by X, which represents the incident wavelength of light source 1 in nm, F is a proportionality constant, and B is a constant.

[0088] Optionally, the test reagent 11 is added to the water sample to obtain the test sample. The incident wavelength of the light source 1 is changed, and the different absorbances corresponding to the same test sample at different wavelengths are recorded. The wavelength-absorbance absorption spectrum curve of the test sample is obtained by fitting. The numerical points of the test parameter that are not absorbed are selected on the wavelength-absorbance absorption spectrum curve of the test sample and the turbidity / or color curve is obtained by fitting.

[0089] At the same wavelength, the absorbance A corresponding to the wavelength-absorbance absorption spectrum curve of the sample under test. L1 Subtract the absorbance A calculated from the turbidity or chromaticity curve in Formula 4. L2 The true absorbance A of the parameter to be measured in the water sample was obtained. L3 , will A L3 Substitute the values ​​into step S300 to calculate the water quality measurement values ​​after eliminating turbidity and / or color interference.

[0090] In one embodiment, taking pH detection as an example, a detection reagent 11 is added to a water sample to obtain a pH test sample. The incident wavelength of the light source 1 is changed, and the light signal is measured by the first signal receiver 5. The different absorbances corresponding to the same pH test sample at different wavelengths are calculated, and the wavelength-absorbance absorption spectrum curve of the pH test sample is obtained by fitting. The value points where pH is not absorbed are selected on the wavelength-absorbance absorption spectrum curve of the pH test sample, and the turbidity or color curve is obtained by fitting.

[0091] It should be noted that, generally, the absorbance of the same pH sample at different wavelengths is measured within the wavelength range of 425–650 nm, and the wavelength-absorbance absorption spectrum curve of the pH sample is obtained by fitting. pH detection generally selects a wavelength range of 500 nm–620 nm, where absorption is relatively strong. For turbidity or color detection in water samples, wavelengths ≥455 nm and / or ≤620 nm can be selected to obtain turbidity or color curves. In this wavelength range, pH has almost no absorption. The signal values ​​(absorbance) of turbidity and / or color at 500 nm–620 nm are obtained by back-calculating from the turbidity or color curve. Subtracting the signal values ​​of turbidity and / or color yields the true pH signal value in the water sample.

[0092] Please refer to Figure 2 The solid black dots represent the degree of absorption in the visible region corresponding to the same turbidity, as indicated by A. L2 This represents its absorbance, while the turbidity in this range is approximately a straight line, which can be fitted to a linear function to obtain A. L2 =F*X+B; The "hollow circle ○" symbol represents the absorption in the visible region after the pH and turbidity mixture is added to test reagent 11, as determined by A. L1Indicates its absorbance; the "triangle △" symbol represents the absorption in the visible region after adding test reagent 11 to the pH standard solution alone, as shown by A. L3 This represents the true absorbance of the sample at its pH value. From... Figure 2 It can be seen that in the wavelength range of 425nm to 455nm and the wavelength range of 620nm to 650nm, the turbidity or color curve and the wavelength-absorbance absorption spectrum curve of the pH test sample after adding the turbidity plus pH and the turbidity or color mixture to the detection reagent 11 are basically the same. Therefore, based on the points between 425nm to 455nm and 620nm to 650nm, the wavelength and absorbance can be matched one-to-one to fit the turbidity or color curve. This curve is consistent with the curve fitted using the same concentration of turbidity or color standard solution in this wavelength range.

[0093] By measuring the absorbance of a sample at the same pH at different wavelengths and fitting the wavelength-absorbance absorption spectrum curve of the pH sample, the turbidity or color curve of the water sample can be obtained simultaneously. Based on the turbidity or color curve equation, A can then be obtained. L2 In A L1 Given that A L2 A can be obtained by dynamically obtaining and calculating the absorption spectrum of the sample under test. L3 A L3 This represents the true absorbance of the pH value of the sample being tested.

[0094] It should be noted that the turbidity and / or color subtraction method in this embodiment is not affected by the water substrate. The turbidity or color curve is generated synchronously with the wavelength-absorbance absorption spectrum curve of the sample to be tested and is obtained dynamically. By using this turbidity and / or color subtraction method, dynamic subtraction of turbidity and / or color of water sample can be achieved, which can meet the water quality measurement needs in different scenarios and has wide applicability.

[0095] Optionally, the light source 1 can be a deuterium-tungsten lamp or a composite light source, which can provide a variety of detection wavelengths to meet different detection needs.

[0096] Optionally, the first signal receiver 5 and the second signal receiver 6 may employ a CCD sensor or an area array detector, thereby enabling the acquisition of light intensity at multiple wavelengths.

[0097] Preferably, a window 7 is provided next to the liquid column 4, and the window 7 is heated to a preset temperature to avoid the generation of water mist. This reduces the impact of airflow on the liquid column 4 and reduces the interference of water mist on the detection optical path.

[0098] Preferably, the cross-section of the outlet of the buffer tank 10 is circular.

[0099] Understandably, to enhance the stability of the liquid column 4 flow, the outlet of the buffer tank 10 is designed with a circular cross-section to effectively avoid water flow turbulence. Furthermore, the edge of the outlet of the buffer tank 10 needs to be smoothly polished (roughness ≤ 0.02 mm), and the outlet direction is vertically downward to prevent the liquid column 4 from dispersing too quickly due to gravity during horizontal spraying. These multiple measures effectively increase the stability of the liquid column 4, which is beneficial for achieving measurement repeatability and effectively improving measurement accuracy.

[0100] It should be noted that, in this document, the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0101] This document uses specific examples to illustrate the principles and implementation methods of this application. The examples are merely for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, and the existence of an infinite number of specific structures, those skilled in the art can make various improvements, modifications, or variations without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, variations, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered as protected by this application.

Claims

1. A water quality measuring device, characterized in that, It includes a light source (1), a first signal receiver (5), and a buffer pool (10); The buffer tank (10) is provided with an inlet and an outlet. The inlet of the buffer tank (10) is used to continuously input the sample to be tested, while the outlet is used to continuously output the sample to be tested so that the liquid level in the buffer tank (10) remains stable and the water flow at the outlet of the buffer tank (10) forms a stable liquid column (4). The light source (1) is set on the first side of the liquid column (4), and the first signal receiver (5) is set on the second side of the liquid column (4). The light emitted by the light source (1) passes through the liquid column (4) and is received by the first signal receiver (5). The first signal receiver (5) is used to measure the light intensity of the received light. The water quality measuring device also includes a beam splitter (2) and a second signal receiver (6). The beam splitter (2) and the second signal receiver (6) are disposed on the first side of the liquid column (4), and the beam splitter (2) is located between the light source (1) and the liquid column (4). The beam splitter (2) is used to transmit a portion of the light emitted by the light source (1) through the liquid column (4) and be received by the first signal receiver (5), while reflecting another portion of the light emitted by the light source (1) to the second signal receiver (6) for reception. The water quality measuring device also includes a first optical focusing assembly (3) and a second optical focusing assembly (4). The focusing component (8) and the third optical focusing component (14) are arranged on opposite sides of the liquid column (4). The light emitted by the light source (1) is focused by the first optical focusing component (3), passes through the liquid column (4), is focused by the third optical focusing component (14), and is transmitted to the first signal receiver (5). The second optical focusing component (8) is arranged between the second signal receiver (6) and the beam splitter (2). The second optical focusing component (8) is used to focus the light reflected by the beam splitter (2) and transmit it to the second signal receiver (6).

2. The water quality measuring device according to claim 1, characterized in that, The water quality measuring device also includes an inlet pipe (12) and an overflow pipe (13). The inlet pipe (12) is connected to the inlet of the buffer tank (10). An inlet pump (9) is installed on the inlet pipe (12). The overflow pipe (13) is connected to the overflow port preset on the side wall of the buffer tank (10).

3. A water quality measurement method, characterized in that, Using the water quality measuring device as described in any one of claims 1-2, the water quality measuring method includes the following steps: S100: The sample to be tested is continuously input through the inlet of the buffer tank (10), and the sample to be tested is continuously output through the outlet of the buffer tank (10) to keep the liquid level in the buffer tank (10) stable and to make the water flow at the outlet of the buffer tank (10) form a stable liquid column (4). The light emitted by the light source (1) passes through the liquid column (4) and is received by the first signal receiver (5) to obtain the real-time transmitted light intensity of the sample to be tested. I ; S200: Absorbance A is calculated using the following formula: A = log ( I 0 / I ) 1; In the formula, I 0 The incident light intensity I The transmitted light intensity is obtained in real time by the first signal receiver (5) when the liquid column (4) contains the sample to be tested; S300: Calculate the content / value of the parameter to be measured in the water sample based on the absorbance A of the parameter to be measured in the water sample.

4. The water quality measurement method according to claim 3, characterized in that, Before step S100, the standard working curve calibration of the parameter to be tested is performed: prepare a variety of standard samples of the parameter to be tested with known content / value, continuously input the standard samples of the parameter to be tested with different content / value through the inlet of the buffer tank (10), and continuously output the standard samples of the parameter to be tested with different content / value through the outlet of the buffer tank (10) to keep the liquid level in the buffer tank (10) stable and to make the water flow at the outlet of the buffer tank (10) form a stable liquid column (4), measure and calculate the absorbance A of each standard sample to be tested, fit the content / value of each standard sample to be tested with the absorbance A one-to-one to obtain the standard working curve of the parameter to be tested, and obtain the linear function equation of the standard working curve: A = a * C + M 2; In the formula, a is a proportionality constant, C represents the content / value of the parameter to be measured, and M is a constant.

5. A water quality measurement method according to claim 3, characterized in that, Before step S100, the incident light intensity of the parameter to be measured in the water sample is obtained. I 0 Pure water is continuously supplied through the inlet of the buffer tank (10), and pure water is continuously discharged from the outlet of the buffer tank (10) to keep the liquid level in the buffer tank (10) stable and to form a stable liquid column (4) from the water flow at the outlet of the buffer tank (10). The light emitted by the light source (1) passes through the liquid column (4) and is received by the first signal receiver (5) to obtain the incident light intensity. I 0 .

6. The water quality measurement method according to claim 5, characterized in that, A beam splitter (2) and a second signal receiver (6) are provided on the first side of the liquid column (4). The beam splitter (2) is located between the light source (1) and the liquid column (4). The beam splitter (2) is used to transmit a portion of the light emitted by the light source (1) through the liquid column (4) and be received by the first signal receiver (5), while reflecting the other portion of the light to the second signal receiver (6) for reception. The beam splitter (2) is used to detect the incident light intensity of the parameters to be measured in the water sample. I 0 During the process, the initial light intensity value K received by the second signal receiver (6) is recorded. When measuring the sample, the light intensity value K received by the second signal receiver (6) is recorded for each water sample measurement. n Calculate K n The ratio of / K is used as I 0 The coefficient of variation, combined with Formula 1, yields the following formula: A = log[ I 0* K n / K) / I] 3.

7. The water quality measurement method according to claim 3, characterized in that, Before step S300, the method also includes: obtaining the turbidity or color curve of the water sample; Change the incident wavelength of the light source (1), record the different absorbances of the same sample under different wavelengths, fit the wavelength-absorbance absorption spectrum curve of the sample, select the value points of the parameter to be measured that are not absorbed on the wavelength-absorbance absorption spectrum of the sample, and fit the turbidity or color curve, which can be expressed by a linear function formula as follows: A L2 =F*X+B 4; In the formula, A L2 X represents the absorbance corresponding to turbidity or chromaticity, X represents the incident wavelength of the light source (1) in nm, F is a proportionality constant, and B is a constant. At the same wavelength, the absorbance A corresponding to the wavelength-absorbance absorption spectrum curve of the sample under test. L1 The absorbance A obtained by subtracting the wavelength-absorbance absorption spectrum curve of turbidity or chromaticity in Formula 4 is... L2 The true absorbance A of the parameter to be measured in the water sample was obtained. L3 , will A L3 Substitute the values ​​into step S300 to calculate the water quality measurement values ​​after eliminating turbidity and / or color interference.

8. A water quality measurement method according to claim 3, characterized in that, A window plate (7) is provided next to the liquid column (4). The window plate (7) is heated to a preset temperature to avoid the generation of water mist.

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