Multi-parameter liquid detection experiment device based on photoelectric effect

Abstract

The invention relates to the technical field of liquid detection, in particular to a photoelectric effect-based multi-parameter liquid detection experimental device, which comprises a photoelectric detection module, a multi-parameter measurement module, an intelligent data processing module and an environment control module. Synchronous measurement of liquid concentration, refractive index and conductivity is realized through the same optical path system, and a multi-parameter correlation model (concentration c =-2.96 ig + 5.69, refractive index n =-0.058 ig + 1.663, and conductivity sigma =-5.20 ig + 30.56) and goodness of fit R2gt are established based on light current signals; 0.99, the relative error lt is measured; 1%. The device is high in integration level and simple and convenient to operate, can be widely applied to the fields of teaching, scientific research and industrial detection, and provides an innovative solution for multi-parameter liquid detection.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of liquid detection, and specifically relates to a multi-parameter liquid detection experimental device integrating photoelectric effect principles. BACKGROUND

[0002] Liquid detection technology has wide application requirements in college experimental teaching, scientific research detection and industrial quality control, especially in the synchronous measurement of multiple physical parameters. However, the existing liquid detection methods have many deficiencies, which are difficult to meet the requirements of efficiency and accuracy in actual application. Traditional detection methods such as spectral analysis method, refractometer method and fluorescence spectroscopy method can only realize the measurement of a single parameter, and cannot simultaneously obtain multiple key indicators such as concentration, refractive index and conductivity. The limitation of such single parameter detection makes users need to perform multiple independent operations to complete comprehensive detection, which not only is low in efficiency, but also increases the experimental complexity and the risk of error accumulation. In addition, the existing devices are often difficult to balance between operation convenience and measurement accuracy. For example, the equipment using the grating light intensity method needs precise optical adjustment, and high-end spectrometers and other instruments are expensive, which significantly increases the experimental cost. These factors limit the widespread application of the devices in teaching and industrial scenarios.

[0003] The lack of multi-parameter integrated detection devices based on the same physical principle in the market also makes it difficult to realize the collaborative measurement and correlation analysis of parameters such as concentration, refractive index and conductivity. Current conductivity measurement methods mostly rely on contact electrodes, which can easily contaminate the liquid to be measured, especially in the detection of corrosive liquids. At the same time, the traditional detection methods have very high requirements for the precision of optical elements, which further increases the manufacturing difficulty and use threshold of the equipment. These problems show that developing a device that can integrate multi-parameter detection functions, is easy to operate and has reasonable cost has become a technical problem to be solved in the field of liquid detection.

[0004] In view of the above problems, the application provides a multi-parameter liquid detection experimental device based on photoelectric effect, which aims to realize the synchronous measurement of liquid concentration, refractive index and conductivity through the same optical system. The device not only solves the problems of single detection parameter, complex operation and high cost in the prior art, but also realizes high-precision and high-reliability multi-parameter detection through non-contact conductivity measurement and intelligent data fusion algorithm. This innovative design provides a new solution for liquid detection technology, and has important teaching and scientific research value and industrial application prospect. SUMMARY

[0005] The present application aims at the problems of single parameter detection limitation, operation complexity and precision contradiction, and the lack of multi-parameter detection equipment in existing liquid detection technology, and provides a multi-parameter liquid detection experimental device based on photoelectric effect.

[0006] The present application provides a multi-parameter liquid detection experimental device based on photoelectric effect, which comprises a photoelectric detection module, a multi-parameter measurement module, an intelligent data processing module and an environment control module. Among them: the photoelectric detection module uses a wavelength adjustable high-pressure mercury lamp as a light source, the characteristic wavelength of which contains 577nm, and a grating and color filter composite light path system is used to realize the wavelength accuracy of monochromatic light ±1nm. Further, the photoelectric tube dark box integrates a low-noise transimpedance amplifier, and the photoelectric current detection resolution reaches 10 -11 A. The light path system is provided with an adjustable diaphragm, and the aperture range is 0.5-10mm to adapt to the light intensity adjustment requirements under different liquid layer thicknesses.

[0007] The multi-parameter measurement module comprises a transparent water tank, a non-contact electromagnetic electrode and a laser collimator. In particular, the transparent water tank is made of quartz glass material, the optical path error is ≤0.1mm, the laser incidence port and the refraction angle sensor are arranged on the two sides respectively, and the non-contact electromagnetic induction electrode is integrated at the bottom. The concentration detection unit is based on the Lambert-Beer law, and the concentration-photoelectric current mapping relationship is established through the photoelectric current signal; the refractive index detection unit measures the refractive angle offset by using the laser collimator and the angle sensor, calculates the refractive index, and the accuracy reaches ±0.0005; the conductivity detection unit adopts the four-electrode method to avoid the electrode polarization effect, and the measurement range is 0.01-1000S / m.

[0008] The intelligent data processing module integrates an FPGA data acquisition system, the sampling frequency is 10kHz, and the photoelectric current, the refraction angle and the voltage current signals are synchronously acquired. Further, an Origin algorithm engine is built-in, the linear equations of photoelectric current and various parameters are fitted in real time, including the concentration-photoelectric current model (c=-2.96i_g+5.69), the refractive index-photoelectric current model (n=-0.058i_g+1.663) and the conductivity-photoelectric current model (σ=-5.20i_g+30.56), and the goodness of fit R 2 is greater than 0.99. In addition, USB / Bluetooth dual-mode data transmission is supported, and the PC end software is matched to realize dynamic display of parameter curves and historical data tracing.

[0009] The environment control module comprises a temperature adjusting and shading system. A PTC heating element and a PT100 temperature sensor are integrated at the bottom of the water tank, the temperature control precision is ±0.5 DEG C, and the influence of the environment is corrected through a temperature compensation algorithm, and the specific compensation formula is P=P0(1+kDeltaT), wherein k=0.002 / DEG C. The shading box adopts a double-layer aluminum alloy structure, the inner wall is plated with a light absorption coating, and the stray light suppression ratio is >1000:1.

[0010] Further, the working principle of the present application is based on photoelectric effect basic measurement, the light intensity attenuation after monochromatic light transmits through the liquid to be measured, and the phototube generates a photoelectric current signal proportional to the remaining light intensity. In particular, the mapping relationship between the photoelectric current and the concentration is established through the Lambert-Beer law, and the photoelectric current-concentration-refractive index mapping relationship is established: c=k*n+b (k=0.042, b=1.332, obtained through pre-calibration), the refractive index is inversely calculated through the concentration, and the double-path calibration is carried out by using the refractive angle measurement. The conductivity measurement is carried out by applying a 100Hz sinusoidal alternating voltage at both ends of the water tank, measuring the current value and combining the liquid geometric parameters (L / S), and calculating the conductivity sigma=(I*L) / (U*S), wherein L=water tank length (50.0±0.1mm), S=electrode cross-sectional area (12.56mm 2 ) square. The intelligent data fusion algorithm corrects the influence of the environment through a temperature compensation mechanism, realizes multi-parameter cross verification through a multivariate linear regression, and improves the measurement reliability.

[0011] In particular, the innovation points of the present application are as follows:

[0012] Firstly, the multi-parameter integrated detection integrates the concentration, refractive index and conductivity detection on the same photoelectric effect platform for the first time, realizes the cooperative measurement of multiple physical quantities through the photoelectric current signal, and improves the detection efficiency by 300%. Secondly, the non-contact conductivity measurement adopts an electromagnetic induction electrode to replace the traditional contact electrode, avoids solution pollution, and is suitable for corrosive liquid detection. Thirdly, the intelligent data fusion algorithm is based on a multi-parameter correlation model (R 2 >0.99) fitted by Origin, combines a temperature compensation mechanism, realizes the measurement error <1% (based on NaCl solution experimental data) in the full range, and has strong expansibility.

[0013] The technical effect of the present application is realized in the following ways: first, through the high-precision optical path system of the photoelectric detection module and the low-noise signal amplification circuit, the high-resolution detection of the photoelectric current signal is ensured. Secondly, the transparent water tank of the multi-parameter measurement module is made of quartz glass material, the optical path error is ≤0.1mm, combined with the non-contact electromagnetic induction electrode, the solution pollution is avoided and the detection accuracy is improved. Thirdly, the intelligent data processing module realizes real-time data processing and multi-parameter cross verification through the FPGA data acquisition system and the multi-linear fitting algorithm, and improves the measurement reliability. Finally, the temperature regulation and light shielding system of the environmental control module reduces the influence of external interference on the measurement results through accurate temperature control and efficient stray light suppression.

[0014] Particularly, the beneficial effects of the present application are embodied in the following aspects: first, the photoelectric effect, Lambert-Beer law, electromagnetic induction and other multi-physical principles are integrated into a single device, providing a multi-parameter correlation analysis teaching platform for college physics experiments. Second, the multi-parameter synchronous measurement time is <5 minutes / sample, which is 4 times more efficient than the traditional method, suitable for batch detection. Third, the core device is modified from a commercial photoelectric effect experiment instrument, reducing the hardware cost by 60% compared with professional multi-parameter detectors. Fourth, the application scenarios are wide, which can be used for chemical raw material purity detection, medical dialysis liquid concentration monitoring, environmental water conductivity monitoring and other fields, compatible with transparent / colored (such as adding 0.1% methylene blue solution) / mixed liquid (such as ethanol-water mixed liquid), and the verification data table is as follows:

[0015]

[0016] In summary, the present application realizes the efficient, accurate and multifunctional integration of the multi-parameter liquid detection experiment device based on photoelectric effect through modular design and intelligent data fusion algorithm, providing an innovative solution for the liquid detection technology field. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 It is a schematic diagram of the overall structure of the present application, showing the layout of the photoelectric detection module, the multi-parameter measurement module, the intelligent data processing module and the environmental control module;

[0018] Figure 2 It is a sectional view of the multi-parameter measurement module, showing the specific structure of the transparent water tank, the non-contact electromagnetic electrode, the laser collimator and the angle sensor;

[0019] Figure 3 It is a data processing flowchart, including signal acquisition, temperature compensation algorithm and multi-linear fitting algorithm processing steps;

[0020] The reference signs are as follows: 1, photoelectric detection module; 2, multi-parameter measurement module; 3, intelligent data processing module; 4, environment control module; 5, wavelength tunable high-pressure mercury lamp; 6, grating-filter composite light path system; 7, photoelectric tube dark box; 8, low-noise transimpedance amplifier; 9, adjustable diaphragm; 10, transparent water tank; 11, non-contact electromagnetic induction electrode; 12, laser collimator; 13, angle sensor; 14, FPGA data acquisition system; 15, Origin algorithm engine; 16, temperature regulation system; 17, light shielding box; 18, PTC heating element; 19, PT100 temperature sensor. DETAILED DESCRIPTION

[0021] The present application provides a multi-parameter liquid detection experimental device based on photoelectric effect, and the specific embodiments of the device are described in detail in the Figure 1 to the Figure 3 , the detailed description of the device. The device includes a photoelectric detection module 1, a multi-parameter measurement module 2, an intelligent data processing module 3 and an environment control module 4, each module cooperates through a standardized interface to realize the synchronous measurement of liquid concentration, refractive index and conductivity. In actual operation, first, the wavelength tunable high-pressure mercury lamp 5 is started, and its characteristic wavelength includes 577 nm, which generates a monochromatic light source in cooperation with the grating-filter composite light path system 6. After the monochromatic light passes through the light path system, the wavelength accuracy of the light reaches ±1 nm. Before the monochromatic light enters the transparent water tank 10, the light intensity is adjusted by the adjustable diaphragm 9 to adapt to the needs of different liquid layer thicknesses. The transparent water tank 10 is made of quartz glass material, and the optical path error is ≤0.1 mm, which ensures the stability of the light path and high-precision measurement. After the monochromatic light transmits through the liquid to be measured, the remaining light intensity is converted into a photocurrent signal by the phototube in the photoelectric tube dark box 7, and the photocurrent is amplified by the low-noise transimpedance amplifier 8. The detection resolution can reach 10 -11 A.

[0022] The transparent water tank 10 in the multi-parameter measurement module 2 is provided with a laser collimator 12 and an angle sensor 13 on both sides, which are used to measure the refractive index of the liquid. The laser collimator 12 emits a laser beam through the liquid in the transparent water tank 10, and the angle sensor 13 receives the refracted laser and records the refraction angle offset. According to the refraction angle offset and the known incident angle, the refractive index of the liquid is calculated, and the accuracy reaches ±0.0005. At the same time, the non-contact electromagnetic induction electrode 11 is integrated at the bottom of the transparent water tank 10, a 100 Hz sinusoidal alternating voltage is applied by using the four-electrode method, and the conductivity is calculated by measuring the current value combined with the liquid geometric parameters L / S. The conductivity measurement range is 0.01-1000 S / m. The non-contact electromagnetic induction electrode 11 avoids the solution pollution problem that may be caused by the traditional contact electrode, and is especially suitable for the detection of corrosive liquid.

[0023] The intelligent data processing module 3 integrates an FPGA data acquisition system 14 with a sampling frequency of 10 kHz, which can collect the photocurrent signal, the refraction angle signal, and the voltage and current signal in real time. The Origin algorithm engine 15 is built-in, which uses the multiple linear fitting algorithm to establish the linear relationship model between the photocurrent and the concentration, the refractive index, and the conductivity. The specific models are as follows: the concentration-photocurrent model c = -2.96i_g + 5.69, the refractive index-photocurrent model n = -0.058i_g + 1.663, and the conductivity-photocurrent model σ = -5.20i_g + 30.56. The goodness of fit R 2 of all the models is greater than 0.99.

[0024] The intelligent data processing module 3 supports USB and Bluetooth dual-mode data transmission, and the matching PC software can dynamically display the parameter curve and trace the historical data. In actual operation, the intelligent data processing module 3 corrects the environmental influence through the temperature compensation algorithm, and the temperature compensation formula is P = P0(1 + kΔT), where k = 0.002 / ℃, which ensures that the measurement error of the full range is less than 1%.

[0025] The environmental control module 4 includes a temperature regulation system 16 and a light shielding box 17. The PTC heating element 18 and the PT100 temperature sensor 19 are integrated at the bottom of the water tank, and the temperature control accuracy reaches ±0.5℃. The PT100 temperature sensor 19 monitors the liquid temperature in the water tank in real time, and the PTC heating element 18 performs accurate temperature control. The light shielding box 17 adopts a double-layer aluminum alloy structure, the inner wall is coated with a light-absorbing coating, the stray light suppression ratio is greater than 1000:1, which effectively reduces the external light interference and improves the measurement accuracy.

[0026] The working principle of the device is as follows: S1, the wavelength adjustable high-pressure mercury lamp 5 generates monochromatic light, which enters the transparent water tank 10 after adjusting the wavelength through the grating-filter composite light path system 6; S2, the monochromatic light attenuates after transmitting through the liquid, and the phototube in the phototube dark box 7 converts the remaining light intensity into a photocurrent signal; S3, the photocurrent signal is amplified by the low-noise transimpedance amplifier 8 and transmitted to the intelligent data processing module 3; S4, the laser collimator 12 emits a laser beam through the liquid, and the angle sensor 13 records the refraction angle offset and transmits it to the intelligent data processing module 3; S5, the non-contact electromagnetic induction electrode 11 applies a 100Hz sinusoidal alternating voltage, measures the current value, and transmits it to the intelligent data processing module 3; S6, the intelligent data processing module 3 synchronously collects the photocurrent signal, the refraction angle signal, and the voltage and current signal through the FPGA data acquisition system 14; S7, the Origin algorithm engine 15 uses the multiple linear fitting algorithm to establish the linear relationship model between the photocurrent and the concentration, the refractive index, and the conductivity, and generates a dynamic calibration model in real time; S8, the environmental influence is corrected through the temperature compensation algorithm, and the multiple linear regression is combined to realize the multi-parameter cross-validation, and the final measurement result is output.

[0027] In a specific application scenario, taking college physics experiment teaching as an example, teachers can use the device to demonstrate the practical application of multiple physical principles such as photoelectric effect, Lambert-Beer law and electromagnetic induction for students. For example, in an experiment, configure NaCl solutions with different concentrations, the concentration range is 0-25%, use an electronic balance and a measuring cylinder to ensure the accuracy of the concentration. After preheating the device for 30 minutes, adjust the light path system so that the 577nm monochromatic light is perpendicular to the center of the water tank, and the aperture of the diaphragm is set to 8mm. After calibrating the temperature sensor, control the water temperature of the water tank to be 23±0.5℃. Then, measure the photocurrent values of different concentrations of the solution, the range is 5.67×10 -10 A to 4.94×10 -10 A, substitute the equation c=-2.96i_g+5.69 to calculate the concentration. At the same time, start the laser collimator 12, measure the refractive angle offset, and combine the photocurrent-concentration model to deduce the refractive index, or directly calibrate through the Abbe refractometer. For conductivity measurement, apply a 2.896V alternating voltage at both ends of the water tank, measure the current value, such as the current is 21.670mA when the concentration is 2%, calculate the conductivity by the formula σ=IL / US, the result is 1.18562S / m. Randomly select the solution with known parameters for verification, the relative error is less than 0.776%.

[0028] In addition, the device can also be widely used in chemical raw material purity detection, medical dialysis fluid concentration monitoring, environmental water conductivity monitoring and other fields. For example, in chemical raw material detection, the device is used to quickly measure the concentration and conductivity of the raw material liquid to determine whether it meets the production requirements. In the medical field, the device can be used to monitor the concentration change of dialysis fluid in real time to ensure the safety of the patient treatment process. In environmental monitoring, the device can detect the conductivity of water in batches to evaluate the water quality.

[0029] In summary, through the cooperative work of the photoelectric detection module 1, the multi-parameter measurement module 2, the intelligent data processing module 3 and the environmental control module 4, the device realizes efficient and accurate measurement of liquid concentration, refractive index and conductivity. The device adopts modular design, supports wavelength expansion and multiple solute detection models, has good scalability and compatibility. Through intelligent data fusion algorithm and temperature compensation mechanism, the measurement reliability and accuracy are significantly improved, which meets the diversified needs of teaching and scientific research and industrial detection fields.

Claims

1. A multi-parameter liquid detection experimental device based on photoelectric effect, comprising a photoelectric detection module (1), a multi-parameter measurement module (2), an intelligent data processing module (3) and an environmental control module (4), characterized in that: The photoelectric detection module (1) comprises a wavelength-adjustable high-pressure mercury lamp (5), a grating-filter composite optical path system (6), a photoelectric tube dark box (7), a low-noise transimpedance amplifier (8), and an adjustable light diaphragm (9); the multi-parameter measurement module (2) comprises a transparent water tank (10), a non-contact electromagnetic induction electrode (11), a laser collimator (12), and an angle sensor (13); the intelligent data processing module (3) comprises an FPGA data acquisition system (14) and an Origin algorithm engine (15); and the environmental control module (4) comprises a temperature regulation system (16) and a light shielding box (17).

2. The multi-parameter liquid detection laboratory device of claim 1, wherein: The characteristic wavelength of the wavelength-adjustable high-pressure mercury lamp (5) comprises 577 nm, and the grating-filter composite optical path system (6) achieves a monochromatic light wavelength accuracy of ±1 nm.

3. The multi-parameter liquid detection laboratory device of claim 2, wherein: The aperture range of the adjustable light diaphragm (9) is 0.5 mm to 10 mm, which is used for adjusting the light intensity to adapt to the needs of different liquid layer thicknesses.

4. The multi-parameter liquid detection laboratory device of claim 1, wherein: The transparent water tank (10) is made of quartz glass, and the optical path error is less than or equal to 0.1 mm, and a laser incident port and a refraction angle sensor (13) are arranged on the two sides, respectively.

5. The multi-parameter liquid detection laboratory device of claim 4, wherein: The non-contact electromagnetic induction electrode (11) adopts a four-electrode method to apply a 100 Hz sinusoidal alternating voltage, and the measurement range is 0.01 S / m to 1000 S / m.

6. The multi-parameter liquid detection laboratory device of claim 1, wherein: The sampling frequency of the FPGA data acquisition system (14) is 10 kHz, which is used for synchronously collecting the photoelectric current signal, the refraction angle signal, and the voltage and current signal.

7. The multi-parameter liquid detection laboratory device of claim 6, wherein: The Origin algorithm engine (15) uses a multivariate linear fitting algorithm to establish a linear relationship model of the photoelectric current and the concentration, the refractive index, and the conductivity, the model coefficients are calibrated by a standard solution and stored in a memory, and the concentration model calibrated by the standard solution is stored.

8. The multi-parameter liquid detection laboratory device of claim 1, wherein: The temperature regulation system (16) comprises a PTC heating element (18) and a PT100 temperature sensor (19), and the temperature control accuracy is ±0.5℃.

9. The multi-parameter liquid detection laboratory device of claim 8, wherein: The temperature regulation system (16) corrects the environmental influence through a temperature compensation formula P=P0(1+kΔT), wherein k=0.002 / ℃.

10. The multi-parameter liquid detection laboratory device of claim 1, wherein: The light shielding box (17) adopts a double-layer aluminum alloy structure, the inner wall is plated with a light-absorbing coating, and the stray light suppression ratio is greater than 1000:1.

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