High-precision turbidity meter detection method based on light scattering and absorption spectrum fusion

Abstract

The invention provides a turbidity meter high-precision detection method based on light scattering and absorption spectrum fusion, relates to the technical field of turbidity meter detection, and aims to solve the problems that complex pretreatment operation is needed, time is consumed, and a large number of chemical reagents are consumed in a traditional method. The method comprises the following steps: S1, firstly, carrying out light scattering detection: measuring light scattering intensity by a turbidity detector and detecting the turbidity of a water sample to be detected according to the intensity; s2, absorption spectrum detection: measuring the absorption spectrum intensity of the water sample to be detected by a turbidity detector, and detecting the turbidity of the water sample to be detected according to the intensity; respectively measuring the absorbance of the water sample to be detected and the measured value when the water sample to be detected does not exist by adopting a continuous light source and a white board; detecting the turbidity of the water sample to be detected according to the detection absorption spectrum intensity; the absorbance of the detected water sample is a measured value when the detected water sample exists, and the absorbance of the white board is a measured value when the detected water sample does not exist. The system can well adapt to severe environments of water environment monitoring and drinking water detection, can effectively guarantee the reliability of water quality monitoring, and is beneficial to water quality improvement.

Description

Technical Field

[0001] The invention belongs to the technical field of turbidity meter detection, and more specifically, particularly relates to a high-precision turbidity meter detection method based on the fusion of light scattering and absorption spectra. Background Art

[0002] Turbidity is an important optical property of water. It characterizes the light scattering characteristics of water and is a comprehensive indicator of suspended particles in various types of water. The turbidity of water not only affects the transparency and color of the water, but also reflects the degree of pollution of the water, which is closely related to the water quality. Excessive turbidity will cause turbidity in the water, resulting in abnormal optical properties and self-purification ability of the water, thereby destroying the water ecological environment and seriously affecting people's production and life. Therefore, accurate detection of turbidity is very important.

[0003] In water environment monitoring, the main methods for detecting turbidity include earth dam spectrophotometer method, colorimetric method, photoelectric perspective method, turbidity meter, etc. These methods can detect turbidity caused by suspended particles, but they are still limited by measurement methods, theoretical basis, etc., and have great defects.

[0004] The main manifestations are: traditional methods often require complex pretreatment operations, which are time-consuming and consume a lot of chemical reagents; some methods require the use of special instruments, which are costly and difficult to operate; and there are differences in the detection accuracy of turbidity meters based on different principles. At present, turbidity data is mainly characterized by absorbance detection, and the conventional detection accuracy can reach 0.1NTU, 0.01NTU, or even 0.001NTU; but for higher turbidity values, the detection accuracy still needs to be improved.

[0005] The existing turbidity meter detection methods mainly use light scattering and absorption spectroscopy. Among them: (1) Forward light scattering turbidimeter, which mainly uses the principle of forward scattering of light to measure turbidity. Its measurement is simple, but it is usually only suitable for measuring low turbidity values, with a large detection limit and an accuracy within 3NTU; (2) Absorption spectrum turbidimeter mainly uses the absorption spectrum of light to measure turbidity. Its measurement is more accurate and has a wide range of applications, but the optical path, water sample concentration and operation method will affect the accuracy of turbidity detection; and when the turbidity is extremely high, the absorption spectrum method will have an error that the turbidity data is significantly smaller, its standard deviation is large, and the accuracy is within 5NTU.

[0006] In order to solve the limitations of the existing turbidity meter detection method and achieve high-precision turbidity detection, the present invention discloses a new turbidity meter detection method. Summary of the invention

[0007] In order to solve the above technical problems, the present invention provides a high-precision turbidity meter detection method based on the fusion of light scattering and absorption spectra to solve the following deficiencies of the existing turbidity detection methods: 1. Traditional methods require complex pretreatment operations, which is time-consuming and consumes a lot of chemical reagents.

[0008] 2. Some methods require the use of special instruments, which are costly and difficult to operate.

[0009] 3. There are differences in the detection accuracy of turbidity meters based on different principles.

[0010] 4. Forward light scattering turbidimeters are usually only suitable for measuring low turbidity values, with a large detection limit and an accuracy within 3NTU.

[0011] 5. Although the absorption spectrum turbidimeter has a relatively accurate measurement and a wide range of applications, the optical path, water sample concentration and operating method will affect the accuracy of turbidity detection; and when the turbidity is extremely high, there will be an error in the turbidity data that is significantly smaller, the standard deviation is large, and the accuracy is within 5NTU.

[0012] The high-precision detection method of the turbidity meter based on the fusion of light scattering and absorption spectrum of the present invention is achieved by the following specific technical means: The high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum includes the following steps: S1. First, light scattering detection is performed: the turbidity detector measures the light scattering intensity and detects the turbidity of the water sample to be tested according to the intensity; S2. Absorption spectrum detection: The turbidity detector measures the absorption spectrum intensity of the water sample to be tested and detects the turbidity of the water sample to be tested based on the intensity: a continuous light source and a white board are used to measure the absorbance of the water sample to be tested, as well as the measured value when there is no water sample to be tested, respectively. The measuring wavelength is between 400nm and 1200nm, and the wavelength interval is less than 3nm; the turbidity of the water sample to be tested is detected based on the absorption spectrum intensity; the absorbance of the water sample to be tested is the measured value when there is a water sample to be tested, and the absorbance of the white board is the measured value when there is no water sample to be tested; S3. Data processing and calibration: Calculate the average value of the light scattering intensity detection value and the absorbance detection value of the measured water sample, record them as the average value of Y1 and Y2 respectively, and obtain the correction factor C according to the following formula; the correction factor C is the slope ratio of the light scattering and absorbance of the water sample of known concentration, and the known concentrations are I1, I2, I3, I4, B1 and C are the light scattering intensity detection value of the water sample of known concentration, the absorbance detection value of the measured water sample and the average light scattering intensity detection value and the average absorbance detection value of the measured water sample respectively; According to the correction coefficient C, the linear relationship between the light scattering detection turbidity Y1 and the absorption spectrum detection turbidity Y2 is obtained, and the correlation coefficient R of the linear regression equation is calculated, and R is recorded as the correlation coefficient between Y1 and Y2; for the light scattering and absorption spectrum detection turbidities Y1 and Y2 with correlation coefficients R less than 0.8, it is necessary to readjust the optical path to obtain an optical path that satisfies the linear correlation, and then re-measure and calculate the correlation coefficient R; for the light scattering and absorption spectrum detection turbidities Y1 and Y2 with correlation coefficients R greater than 0.8, execute step S4; S4. Turbidity value output and display: The turbidity meter detects water samples of unknown concentration and outputs the corresponding turbidity value and turbidity value display.

[0013] Wherein, the step S1 specifically comprises: the turbidity detector measures the light scattering intensity of the water sample to be tested at different angles and detects the turbidity of the water sample to be tested according to the intensity; When the concentration of the water sample to be tested is lower than 500NTU, a fixed light source and detection device are used to measure the light scattering intensity once, and the turbidity Y1 of the water sample to be tested is detected using the following formula; Y1=A×L×∑F; Y1 is the turbidity value detected by light scattering intensity; A is the light scattering coefficient; L is the response area of ​​light scattering intensity; ∑F is the value of light scattering intensity at all angles; When the concentration of the water sample to be tested is higher than 500NTU, a fixed light source and a detection device are used to sequentially measure the light scattering intensity in 360 degrees, and each direction is measured once to obtain the light scattering intensity values ​​at 360 different angles. Then the following formula is used to detect the turbidity Y1 of the water sample to be tested; Y1=A×L×∑F; Y1 is the turbidity value detected by light scattering intensity; A is the light scattering coefficient; L is the response area of ​​the light scattering intensity; ∑F is the value of the light scattering intensity at all angles.

[0014] Among them, the step S1 is specifically: the turbidity detector detects the turbidity Y1 of the water sample to be tested by simultaneously measuring the light scattering intensity at multiple angles.

[0015] Wherein, the step S1 specifically comprises: measuring the multi-angle light scattering intensity of the water sample to be tested and the reference water sample at the same time, and then using the following formula to detect the turbidity Y1 of the water sample to be tested; Y1=(A-Y0)×L×(CA) / (C-Y0)×((∑Ff×f0+∑Ff); Y1 is the turbidity value of light scattering intensity detection; A is the light scattering coefficient; Y0 is the light scattering coefficient of the reference water sample; L is the response area of ​​the light scattering intensity; ∑F is the value of the light scattering intensity of the tested water sample at all angles; ∑Ff is the average of the light scattering intensities of the tested water sample and the reference water sample; f is the reference factor of the tested water sample; f0 is the reference factor of the reference water sample.

[0016] Among them, step S2 is specifically: using a continuous light source and a white board to measure, testing the absorbance at distances of 1 cm, 2 cm, 3 cm, 4 cm and 5 cm respectively, and testing 3 times at each absorbance, and calculating the average of the 3 tests to obtain the average of 5 different absorbances.

[0017] Wherein, the step S3 is specifically as follows: in the linear detection area of ​​low concentration water samples of 500NTU and below 500NTU, the linear regression equation is: (1) Measure the absorbance B1 of a water sample with a known concentration; (2) Measure the light scattering intensity Y1 of a water sample with a known concentration; (3) Obtaining the slope ratio C of the light scattering and absorption spectra of a water sample of known concentration; (4) If the correlation coefficient R of the linear detection area of ​​low-concentration water samples of 500 NTU and below is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; In the linear detection area of ​​high concentration water samples above 500 NTU, the linear regression equation is: (1) Measure the absorbance B2 of a water sample of known concentration; (2) Measure the light scattering intensity Y2 of a water sample with a known concentration; (3) Obtaining the slope ratio C of the light scattering and absorption spectra of high-concentration water samples; (4) If the correlation coefficient R of the linear detection area of ​​high-concentration water samples above 500 NTU is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; In the 500NTU concentration water sample detection area, the linear regression equation is: (1) Measure the absorbance B3 of a water sample of known concentration; (2) Measure the light scattering intensity Y3 of a water sample of known concentration; (3) Obtain the slope ratio C of the light scattering and absorption spectra of medium-concentration water samples; (4) If the correlation coefficient R of the linear detection area of ​​high-concentration water samples above 500 NTU is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; (5) According to the slope ratio C, the linear regression equations of the three turbidity detection areas are obtained, where C1 represents the slope ratio of (1), C2 represents the slope ratio of (2), and C3 represents the slope ratio of (3).

[0018] Wherein, the step S4 is specifically as follows: (1) Measure the absorbance B of the water sample of unknown concentration and substitute it into three linear regression curves to obtain the concentration values ​​of the three turbidity detection areas; (2) Substituting the concentration values ​​of the three turbidity detection areas into the corresponding linear regression equations respectively, and obtaining the turbidity values ​​Y1, Y2, and Y3 of the three turbidity detection areas; (3) Find the average value of Y1, Y2, and Y3, which is the true value of the water sample of unknown concentration.

[0019] Wherein, the step S4 is specifically as follows: (1) Measure the absorbance B of the water sample of unknown concentration and substitute it into three linear regression curves to obtain the concentration values ​​of the three turbidity detection areas; (2) Substituting the concentration values ​​of the three turbidity detection areas into the corresponding linear regression equations respectively, and obtaining the turbidity values ​​Y1, Y2, and Y3 of the three turbidity detection areas; (3) Find the average value of Y1, Y2, and Y3, which is the true value of the water sample of unknown concentration.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects: 1. The present invention overcomes the limitations of single-principle detection methods by integrating the two turbidity detection principles of light scattering and absorption spectroscopy, effectively improves the turbidity detection accuracy, effectively avoids the defects of single-principle detection methods, and meets the requirements for turbidity detection accuracy in fields such as water environment monitoring and drinking water testing.

[0021] 2. The present invention is particularly aimed at high turbidity water samples. Due to their poor light transmittance, accurate turbidity values ​​are often unable to be obtained in absorption spectroscopy. By integrating the light scattering detection principle, the turbidity value can be corrected more accurately, greatly improving the detection reliability.

[0022] 3. The turbidity detection device used in the present invention can simultaneously measure the absorbance and light scattering intensity of the water sample to be tested, which can effectively reduce the error of turbidity detection and ensure extremely high accuracy regardless of whether it is a low-concentration or high-concentration water sample.

[0023] 4. The fusion method adopted in the present invention can effectively provide a more reliable and stable turbidity detection method.

[0024] 5. The present invention can well adapt to the harsh environment of water environment monitoring and drinking water testing, can effectively ensure the reliability of water quality monitoring, and is conducive to improving water quality.

[0025] 6. The present invention provides key technical support for water quality monitoring and water environment protection, and is of great significance to health.

[0026] 7. The method proposed in the present invention can be widely used in fields such as water environment monitoring and drinking water testing, and has broad prospects for market application and industrialization. DETAILED DESCRIPTION

[0027] The embodiments of the present invention are described in further detail below. Example

[0028] The high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum includes the following steps: S1. First, perform light scattering detection: the turbidity detector measures the light scattering intensity and detects the turbidity of the water sample to be tested based on the intensity; in more detail, between the light source, collimating lens, sample chamber and photodetector, light is emitted at a certain incident angle α (generally selected from 30° to 80°) and the scattered light intensity is detected. The backscattering coefficient β of the sample can be obtained through the functional relationship between the light intensity and the detection parameters (incident light intensity, sample cell diameter, incident angle). The backscattering coefficient is converted into a turbidity value T1 using the calibrated related parameters.

[0029] S2. Absorption spectrum detection: The turbidity detector measures the absorption spectrum intensity of the water sample to be tested and detects the turbidity of the water sample to be tested based on the intensity: a continuous light source and a white board are used to measure the absorbance of the water sample to be tested and the measured value when there is no water sample to be tested, respectively. The measuring wavelength is between 400nm and 1200nm, and the wavelength interval is less than 3nm; the turbidity of the water sample to be tested is detected based on the detected absorption spectrum intensity; the absorbance of the water sample to be tested is the measured value when there is a water sample to be tested, and the absorbance of the white board is the measured value when there is no water sample to be tested; light is set to enter between the light source, monochromator, sample chamber, photodetector and spectral data processing equipment in sequence to obtain the absorption peak spectral data of the spectral transmission curve, and the absorption coefficient γ is obtained based on the functional relationship between the absorption coefficient γ at the absorption peak position and the spectral transmittance T(λ); the turbidity value T2, that is, the absorption coefficient within the unit optical path and wavelength range, is obtained using the calibrated parameters and related detection parameters (sample cell diameter, detection band range).

[0030] S3. Data processing and calibration: Calculate the average values ​​of the light scattering intensity detection value and the absorbance detection value of the tested water sample, record them as the average values ​​of Y1 and Y2 respectively, and obtain the correction coefficient C according to the following formula; the correction coefficient C is the slope ratio of the light scattering and absorbance of the water sample with known concentration, and the known concentrations I1, I2, I3, I4, B1 and C are the light scattering intensity detection value of the water sample with known concentration, the absorbance detection value of the tested water sample and the average light scattering intensity detection value and the average absorbance detection value of the tested water sample respectively; use the data fusion algorithm to fuse the detection parameters, absorption coefficient, light intensity and other data to obtain the turbidity value T, and use the calibrated parameters to obtain the corrected turbidity value T0.

[0031] According to the correction coefficient C, the linear relationship between the light scattering detection turbidity Y1 and the absorption spectrum detection turbidity Y2 is obtained, and the correlation coefficient R of the linear regression equation is calculated, and R is recorded as the correlation coefficient between Y1 and Y2; for the light scattering and absorption spectrum detection turbidities Y1 and Y2 with correlation coefficients R less than 0.8, it is necessary to readjust the optical path to obtain an optical path that satisfies the linear correlation, and then re-measure and calculate the correlation coefficient R; for the light scattering and absorption spectrum detection turbidities Y1 and Y2 with correlation coefficients R greater than 0.8, execute step S4; S4. Turbidity value output and display: The turbidity meter detects water samples of unknown concentration and outputs the corresponding turbidity value and turbidity value display. T0 is intuitively displayed as a turbidity value through the display instrument and transmitted to the data storage device for storage, which is convenient for subsequent analysis and processing.

[0032] Further, step S1 is specifically as follows: the turbidity detector measures the light scattering intensity of the water sample to be tested at different angles and detects the turbidity of the water sample to be tested according to the intensity; When the concentration of the water sample to be tested is lower than 500NTU, a fixed light source and detection device are used to measure the light scattering intensity once, and the turbidity Y1 of the water sample to be tested is detected using the following formula; Y1=A×L×∑F; Y1 is the turbidity value detected by light scattering intensity; A is the light scattering coefficient; L is the response area of ​​light scattering intensity; ∑F is the value of light scattering intensity at all angles; When the concentration of the water sample to be tested is higher than 500NTU, a fixed light source and a detection device are used to sequentially measure the light scattering intensity in 360 degrees, and each direction is measured once to obtain the light scattering intensity values ​​at 360 different angles. Then the following formula is used to detect the turbidity Y1 of the water sample to be tested; Y1=A×L×∑F; Y1 is the turbidity value detected by light scattering intensity; A is the light scattering coefficient; L is the response area of ​​the light scattering intensity; ∑F is the value of the light scattering intensity at all angles.

[0033] Furthermore, step S1 is specifically as follows: the turbidity detector detects the turbidity Y1 of the water sample to be tested by simultaneously measuring the light scattering intensity at multiple angles.

[0034] Further, step S1 is specifically: measuring the multi-angle light scattering intensity of the water sample to be tested and the reference water sample at the same time, and then using the following formula to detect the turbidity Y1 of the water sample to be tested; Y1=(A-Y0)×L×(CA) / (C-Y0)×((∑Ff×f0+∑Ff); Y1 is the turbidity value of light scattering intensity detection; A is the light scattering coefficient; Y0 is the light scattering coefficient of the reference water sample; L is the response area of ​​the light scattering intensity; ∑F is the value of the light scattering intensity of the tested water sample at all angles; ∑Ff is the average of the light scattering intensities of the tested water sample and the reference water sample; f is the reference factor of the tested water sample; f0 is the reference factor of the reference water sample.

[0035] Furthermore, step S2 is specifically as follows: using a continuous light source and a white board for measurement, testing the absorbance at distances of 1 cm, 2 cm, 3 cm, 4 cm and 5 cm respectively, and testing 3 times at each absorbance, and calculating the average of the 3 tests to obtain the average of 5 different absorbances.

[0036] Further, step S3 is specifically as follows: in the linear detection area of ​​low concentration water samples of 500 NTU and below 500 NTU, the linear regression equation is: (1) Measure the absorbance B1 of a water sample with a known concentration; (2) Measure the light scattering intensity Y1 of a water sample with a known concentration; (3) Obtaining the slope ratio C of the light scattering and absorption spectra of a water sample of known concentration; (4) If the correlation coefficient R of the linear detection area of ​​low-concentration water samples of 500 NTU and below is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; In the linear detection area of ​​high concentration water samples above 500 NTU, the linear regression equation is: (1) Measure the absorbance B2 of a water sample of known concentration; (2) Measure the light scattering intensity Y2 of a water sample with a known concentration; (3) Obtaining the slope ratio C of the light scattering and absorption spectra of high-concentration water samples; (4) If the correlation coefficient R of the linear detection area of ​​high-concentration water samples above 500 NTU is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; In the 500NTU concentration water sample detection area, the linear regression equation is: (1) Measure the absorbance B3 of a water sample of known concentration; (2) Measure the light scattering intensity Y3 of a water sample of known concentration; (3) Obtain the slope ratio C of the light scattering and absorption spectra of medium-concentration water samples; (4) If the correlation coefficient R of the linear detection area of ​​high-concentration water samples above 500 NTU is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; (5) According to the slope ratio C, the linear regression equations of the three turbidity detection areas are obtained, where C1 represents the slope ratio of (1), C2 represents the slope ratio of (2), and C3 represents the slope ratio of (3).

[0037] Further, step S4 is specifically: (1) Measure the absorbance B of the water sample of unknown concentration and substitute it into three linear regression curves to obtain the concentration values ​​of the three turbidity detection areas; (2) Substituting the concentration values ​​of the three turbidity detection areas into the corresponding linear regression equations respectively, and obtaining the turbidity values ​​Y1, Y2, and Y3 of the three turbidity detection areas; (3) Find the average value of Y1, Y2, and Y3, which is the true value of the water sample of unknown concentration.

[0038] Further, step S4 is specifically: (1) Measure the absorbance B of the water sample of unknown concentration and substitute it into three linear regression curves to obtain the concentration values ​​of the three turbidity detection areas; (2) Substituting the concentration values ​​of the three turbidity detection areas into the corresponding linear regression equations respectively, and obtaining the turbidity values ​​Y1, Y2, and Y3 of the three turbidity detection areas; (3) Find the average value of Y1, Y2, and Y3, which is the true value of the water sample of unknown concentration.

[0039] More specifically, in S1, the calibrated light scattering detection related parameters are used, specifically: The backscattering coefficient β of the sample at the detection wavelength is obtained using the following formula (1), specifically: In the formula, Iλ is the light intensity in the sample cell, I0 is the light intensity in the reference cell, α is the incident light angle, ε is the absorption coefficient, β is the backscattering coefficient, and r is the radius of the sample cell; The backscattering coefficient is converted into the turbidity value T1 using the following formula (2): In the formula, T1 is the turbidity value converted from the backscattering coefficient, β is the backscattering coefficient, l is the optical path length, and k is the correction coefficient.

[0040] The absorption coefficient γ of the sample at the detection wavelength is obtained using the following formula (3), specifically: In the formula, A(λ) is the absorption spectrum, T(λ) is the transmission spectrum, n is the attenuation constant, l is the optical path length, β is the backscattering coefficient, α is the incident light angle, and T1 is the turbidity value; The turbidity value T2 is obtained by the detection using the following formula (4), specifically: In the formula, T2 is the turbidity value obtained by absorption spectrum detection, α is the incident light angle, β is the backscattering coefficient, l is the optical path length, k is the correction coefficient, ε is the absorption coefficient, and d is the sample cell diameter.

[0041] In S3, the fused data is as follows: The corrected turbidity value T0 is obtained by using the data fusion algorithm using the following formula (5), specifically: In the formula, T0 is the turbidity value based on the fused data, T1 and T2 are the light scattering and absorption spectrum values, α is the incident light angle, β is the backscattering coefficient, l is the optical path length, k is the correction coefficient, ε is the absorption coefficient, d and δ are the sample cell diameter and correction parameter, respectively, and θ is the correction parameter.

[0042] The present invention is based on the high-precision detection method of the turbidity meter based on the fusion of light scattering and absorption spectrum, which adopts the detection principle of light scattering and absorption spectrum. The specific process is as follows: 1) At a certain incident angle, light is emitted from the light source, collimating lens, sample chamber and photodetector, and the scattered light intensity is detected to obtain a light scattering curve. The absorption coefficient can be obtained based on the functional relationship between light intensity and detection parameters (incident light intensity, sample cell diameter, incident angle). The calibrated parameters are used to calculate the corresponding turbidity value.

[0043] 2) Light is set between the light source, monochromator, sample chamber, photodetector and spectral data processing equipment, and the absorption coefficient is obtained according to the functional relationship between the absorption coefficient at the absorption peak position and the spectral transmittance. The turbidity value is obtained using the calibrated parameters and related detection parameters (sample cell diameter, detection band range).

[0044] 3) Establish a fusion algorithm based on the experimental calibration data and obtain more accurate turbidity values ​​through data fusion.

[0045] 4) The data is stored in a data storage device of the turbidity meter, and the turbidity values ​​obtained in the above steps are intuitively displayed as turbidity values ​​through a display instrument to facilitate subsequent processing and analysis.

[0046] 5) The present invention provides a technical solution that integrates the light scattering and absorption spectrum detection principles, which can effectively improve the detection accuracy of the turbidity meter and is beneficial to water quality monitoring and control.

[0047] The present invention is suitable for detecting the turbidity value of turbid liquids, and is particularly suitable for detecting high-concentration turbid water samples, such as turbidity value detection in sewage treatment processes, water environment detection, and beverage preparation processes.

[0048] Based on the light scattering detection principle, the present invention integrates light absorption spectroscopy technology, which can effectively solve the problem of inaccurate detection results for high-concentration turbid water samples and ensure detection accuracy for low-concentration turbid water samples, which is helpful for fields such as water environment monitoring and environmental governance that have high requirements for turbidity value detection accuracy.

[0049] During specific implementation, relevant technical parameters of light scattering and absorption spectrum detection, such as the diameter of the sample cell, etc., can be appropriately adjusted according to the requirements of turbidity detection.

[0050] In order to verify the detection accuracy of the light scattering and absorption spectrum fusion detection method proposed in the present invention, the light scattering detection method, the absorption spectrum detection method and the light scattering and absorption spectrum fusion detection method of the present invention are compared for water samples of different concentrations.

[0051] Detection method: The diameter of the sample cell is 3 cm, the incident angle is 0°, and the light scattering curve of the water sample is measured.

[0052] The spectral transmission curve is obtained by absorption spectrum detection, and the position of the spectral absorption peak is obtained. The absorption coefficient γ is calculated according to formula (3). The absorption coefficient is calculated to be 2.01cm-1 at a wavelength of 650nm and within a unit optical path and wavelength range. According to the relevant parameters obtained by absorption spectrum detection, such as formula (4), the turbidity value is detected at around 2000NTU to obtain the turbidity value T2 of the water sample.

[0053] Through the data fusion algorithm, that is, the turbidity value T0 of formula (5), the turbidity values ​​of light scattering detection and absorption spectrum detection are fused, and the fused turbidity value is compared with the traditional turbidity value to obtain the result. It is found that the detection result of the present invention is closer to the true value than the detection result of the traditional method.

[0054] In practical applications, the present invention was used to compare various turbid water samples based on actual test data, and the following test results were obtained: A. In the actual sample detection process, if the turbidity detection result is inaccurate, the detection method of the present invention can be used to effectively correct it, so as to obtain the correct turbidity detection result, which can effectively avoid the wrong judgment caused by the wrong turbidity value detection result.

[0055] B. During the turbidity detection process, the detection method proposed in the present invention is used to more accurately detect the turbidity of the water sample, effectively ensuring that the turbidity detection data can accurately reflect the water quality of the water sample, improve the detection accuracy, and facilitate water quality monitoring and control.

[0056] C. The present invention effectively reduces the error of turbidity value detection by integrating light absorption spectrum and light scattering detection, which is beneficial to water environment monitoring and analysis and provides support for environmental protection and water quality improvement.

[0057] The present invention proposes a detection method for turbidity value by integrating light scattering and absorption spectrum, which can effectively correct the detection results of high-concentration turbid water samples and reduce the turbidity value error, which is beneficial to water environment monitoring and drinking water testing, etc. This method combines light scattering detection and absorption spectroscopy detection to achieve high-precision turbidity detection through the following steps: Light scattering detection: Use a laser beam to illuminate the water sample to be tested, obtain the forward scattered and backscattered light intensities through a light intensity detector, convert them into electrical signals, and calculate the forward scattering ratio and backscattering ratio.

[0058] Absorption spectrum detection: Using a tunable light source or a broadband light source, the transmission spectrum of the water sample is collected through a spectral detector, and the absorption spectrum is obtained through rapid spectral filtering.

[0059] Data processing and calibration: Combine the scattering coefficient and extinction coefficient to estimate the turbidity coefficient of the water sample, and compare it with the turbidity calibration curve to calculate the turbidity value.

[0060] Turbidity value output and display: The calculated turbidity value is output to the turbidity meter host through communication transmission and displayed.

[0061] As described above, the present invention solves the problem of inaccurate detection results of the traditional single turbidity principle detection method when detecting high-concentration water samples by integrating the two turbidity detection principles of light scattering and absorption spectroscopy, thereby effectively improving the turbidity detection accuracy. The present invention has a wide market space and practical application value, and can be widely used in water quality monitoring and treatment, beverage preparation and other fields, providing key technical support for environmental protection and environmental governance.

[0062] The present invention has many specific application paths. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements can be made without departing from the principle of the present invention. These improvements should also be regarded as the protection scope of the present invention.

[0063] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

[0064] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A high-precision turbidity meter detection method based on the fusion of light scattering and absorption spectra, characterized in that: The steps include: S1. First, light scattering detection is performed: the turbidity detector measures the light scattering intensity and detects the turbidity of the water sample to be tested according to the intensity; S2. Absorption spectrum detection: The turbidity detector measures the absorption spectrum intensity of the water sample to be tested and detects the turbidity of the water sample to be tested based on the intensity: a continuous light source and a white board are used to measure the absorbance of the water sample to be tested, as well as the measured value when there is no water sample to be tested, respectively. The measuring wavelength is between 400nm and 1200nm, and the wavelength interval is less than 3nm; the turbidity of the water sample to be tested is detected based on the absorption spectrum intensity; the absorbance of the water sample to be tested is the measured value when there is a water sample to be tested, and the absorbance of the white board is the measured value when there is no water sample to be tested; S3. Data processing and calibration: Calculate the average value of the light scattering intensity detection value and the absorbance detection value of the measured water sample, record them as the average value of Y1 and Y2 respectively, and obtain the correction factor C according to the following formula; the correction factor C is the slope ratio of the light scattering and absorbance of the water sample of known concentration, and the known concentrations are I1, I2, I3, I4, B1 and C are the light scattering intensity detection value of the water sample of known concentration, the absorbance detection value of the measured water sample and the average light scattering intensity detection value and the average absorbance detection value of the measured water sample respectively; According to the correction coefficient C, the linear relationship between the light scattering detection turbidity Y1 and the absorption spectrum detection turbidity Y2 is obtained, and the correlation coefficient R of the linear regression equation is calculated, and R is recorded as the correlation coefficient between Y1 and Y2; for the light scattering and absorption spectrum detection turbidities Y1 and Y2 with correlation coefficients R less than 0.8, it is necessary to readjust the optical path to obtain an optical path that satisfies the linear correlation, and then re-measure and calculate the correlation coefficient R; for the light scattering and absorption spectrum detection turbidities Y1 and Y2 with correlation coefficients R greater than 0.8, execute step S4; S4. Turbidity value output and display: The turbidity meter detects water samples of unknown concentration and outputs the corresponding turbidity value and turbidity value display.

2. The high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum according to claim 1 is characterized in that: The step S1 specifically comprises: the turbidity detector measures the light scattering intensity of the water sample to be tested at different angles and detects the turbidity of the water sample to be tested according to the intensity; When the concentration of the water sample to be tested is lower than 500NTU, a fixed light source and detection device are used to measure the light scattering intensity once, and the turbidity Y1 of the water sample to be tested is detected using the following formula; Y1=A×L×∑F; Y1 is the turbidity value detected by light scattering intensity; A is the light scattering coefficient; L is the response area of ​​light scattering intensity; ∑F is the value of light scattering intensity at all angles; When the concentration of the water sample to be tested is higher than 500NTU, a fixed light source and a detection device are used to sequentially measure the light scattering intensity in 360 degrees, and each direction is measured once to obtain the light scattering intensity values ​​at 360 different angles. Then the following formula is used to detect the turbidity Y1 of the water sample to be tested; Y1=A×L×∑F; Y1 is the turbidity value detected by light scattering intensity; A is the light scattering coefficient; L is the response area of ​​the light scattering intensity; ∑F is the value of the light scattering intensity at all angles.

3. The high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum according to claim 2 is characterized in that: The step S1 is specifically as follows: the turbidity detector detects the turbidity Y1 of the water sample to be tested by simultaneously measuring the light scattering intensity at multiple angles.

4. The high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum according to claim 3 is characterized in that: The step S1 specifically comprises: measuring the multi-angle light scattering intensity of the water sample to be tested and the reference water sample at the same time, and then using the following formula to detect the turbidity Y1 of the water sample to be tested; Y1=(A-Y0)×L×(CA) / (C-Y0)×((∑Ff×f0+∑Ff); Y1 is the turbidity value of light scattering intensity detection; A is the light scattering coefficient; Y0 is the light scattering coefficient of the reference water sample; L is the response area of ​​the light scattering intensity; ∑F is the value of the light scattering intensity of the measured water sample at all angles; ∑Ff is the average value of the light scattering intensity of the measured water sample and the reference water sample; f is the reference factor of the measured water sample; f0 is the reference factor of the reference water sample.

5. The high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum according to claim 1 is characterized in that: The step S2 is specifically as follows: using a continuous light source and a white board for measurement, testing the absorbance at distances of 1 cm, 2 cm, 3 cm, 4 cm and 5 cm respectively, and testing 3 times at each absorbance, and calculating the average of the 3 tests to obtain the average of 5 different absorbances.

6. According to claim 1, the high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum is characterized in that: The step S3 is specifically as follows: in the linear detection region of low concentration water samples of 500 NTU and below, the linear regression equation is: (1) Measure the absorbance B1 of a water sample with a known concentration; (2) Measure the light scattering intensity Y1 of a water sample with a known concentration; (3) Obtaining the slope ratio C of the light scattering and absorption spectra of a water sample of known concentration; (4) If the correlation coefficient R of the linear detection area of ​​low-concentration water samples of 500 NTU and below is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; In the linear detection area of ​​high concentration water samples above 500 NTU, the linear regression equation is: (1) Measure the absorbance B2 of a water sample of known concentration; (2) Measure the light scattering intensity Y2 of a water sample with a known concentration; (3) Obtaining the slope ratio C of the light scattering and absorption spectra of high-concentration water samples; (4) If the correlation coefficient R of the linear detection area of ​​high-concentration water samples above 500 NTU is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; In the 500NTU concentration water sample detection area, the linear regression equation is: (1) Measure the absorbance B3 of a water sample of known concentration; (2) Measure the light scattering intensity Y3 of a water sample of known concentration; (3) Obtain the slope ratio C of the light scattering and absorption spectra of medium-concentration water samples; (4) If the correlation coefficient R of the linear detection area of ​​high-concentration water samples above 500 NTU is less than 0.8, the optical path needs to be recalibrated and steps (1) to (3) need to be measured again under the new optical path until R is greater than 0.8; (5) According to the slope ratio C, the linear regression equations of the three turbidity detection areas are obtained, where C1 represents the slope ratio of (1), C2 represents the slope ratio of (2), and C3 represents the slope ratio of (3).

7. The high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum according to claim 1 is characterized in that: The step S4 is specifically: (1) Measure the absorbance B of the water sample of unknown concentration and substitute it into three linear regression curves to obtain the concentration values ​​of the three turbidity detection areas; (2) Substituting the concentration values ​​of the three turbidity detection areas into the corresponding linear regression equations respectively, and obtaining the turbidity values ​​Y1, Y2, and Y3 of the three turbidity detection areas; (3) Find the average value of Y1, Y2, and Y3, which is the true value of the water sample of unknown concentration.

8. The high-precision detection method of turbidity meter based on the fusion of light scattering and absorption spectrum according to claim 1 is characterized in that: The step S4 is specifically: (1) Measure the absorbance B of the water sample of unknown concentration and substitute it into three linear regression curves to obtain the concentration values ​​of the three turbidity detection areas; (2) Substituting the concentration values ​​of the three turbidity detection areas into the corresponding linear regression equations respectively, and obtaining the turbidity values ​​Y1, Y2, and Y3 of the three turbidity detection areas; (3) Find the average value of Y1, Y2, and Y3, which is the true value of the water sample of unknown concentration.