CN115508311A - Transparent solution concentration measuring device and method based on hollow triangular prism lens - Google Patents
Transparent solution concentration measuring device and method based on hollow triangular prism lens Download PDFInfo
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Abstract
The invention discloses a transparent solution concentration measuring device and a transparent solution concentration measuring method based on a hollow triangular prism lens, wherein the measuring method comprises the following steps: positioning identification, device assembly, CCD sensor adjustment, initial position measurement, theoretical deviation value measurement, standard sample solution preparation, actual deviation value measurement, concentration scale fitting, sample deviation value measurement and sample concentration calculation. The measuring device comprises a light path forming unit and an image acquisition unit; the light path forming unit comprises a machine-organ emitter, a convex lens and a hollow triangular prism lens which are arranged according to a light path to form refraction light; the image acquisition unit comprises an optical screen arranged on the refraction light projection surface and a CCD sensor used for acquiring images of the optical screen, and the CCD sensor is electrically connected with the image acquisition card to acquire and store the images. The method has the characteristics of simple and rapid measurement, capability of measuring the concentration of the solution in real time, small error of a measurement result and good repeatability.
Description
Technical Field
The invention relates to the technical field of liquid concentration measuring devices, in particular to a transparent solution concentration measuring device based on a hollow triangular prism lens.
Background
Concentration is an important physical quantity for characterizing the solution, and high-precision measurement of the solution concentration plays an important role in the industrial production and processing processes. For example: in the chemical field, chemicals such as petroleum reagents and the like need to be measured to determine the concentration value of the solution. In the field of food, the quality of food can be judged according to the concentration of a solution in the food. In the agricultural field, it is often necessary to detect the concentration of a pesticide or the residual rate of a pesticide. In the environmental field, the water quality condition of a water area can be judged by measuring the water quality concentration.
The conventional solution concentration measurement method includes: hydrometric, sonic and spectroscopic methods. The hydrometric method measures the specific gravity of the liquid to be measured by utilizing a liquid specific gravity balance, and determines the corresponding solution concentration according to the specific gravity of the liquid, but the operation steps are more complicated; the acoustic wave method indirectly measures the concentration of a solution by using reflected wave characteristics, amplitude characteristics, phase difference characteristics, wave spectrum characteristics and the like of acoustic waves, but the measurement result is easily influenced by environmental factors. Spectroscopy is the indirect measurement of solution concentration mainly by using the properties of light such as refraction, interference, diffraction, etc.
Disclosure of Invention
The invention aims to provide a transparent solution concentration measuring device based on a hollow triangular prism lens, which has the characteristics of simple and rapid measurement, capability of measuring the concentration of a solution in real time, small error of a measurement result and good repeatability.
The invention can be realized by the following technical scheme:
the invention discloses a method for measuring the concentration of a transparent solution based on a hollow triangular prism lens, which comprises the following steps:
(1) And positioning identification: the specific positions of a laser emitter, a convex lens, a horizontal table, a hollow triangular prism lens, an optical screen (containing checkered paper) and a CCD sensor are marked on the horizontal plate table and are placed on a horizontal plane;
(2) And assembling the device: the method comprises the following steps that the position of a laser emitter is taken as an initial point, a convex lens is arranged away from the laser emitter, a horizontal table is arranged at the other side away from the convex lens, the position where a hollow triangular prism lens is arranged is determined on the horizontal table, a fixing support is arranged, so that a light beam of the laser emitter is converted into a parallel light beam through the convex lens, the parallel light beam can correspondingly refract after passing through the hollow triangular prism lens filled with solution, an optical screen capable of moving left and right is arranged away from the horizontal table, a CCD sensor is not fixed in the position and can be arranged according to specific conditions, and the CCD sensor is connected through an image acquisition card to acquire and store data;
(3) And adjusting the CCD sensor: adjusting the focal length and the brightness of the CCD sensor to enable the picture displayed by the CCD on a computer to be clear;
(4) And measuring an initial position: starting a laser emitter, adjusting the parallel light beams passing through the convex lens to coincide with the longitudinal edge of the checkered paper in the light screen, and recording the position of the edge as y 1 ;
(5) And measuring a theoretical offset position: distilled water is poured into the triangular prism, the volume of the poured solution is controlled to be half of the volume of the triangular prism, the triangular prism must be placed at the same position, the position of each face of the triangular prism cannot be changed, and at the moment, y is arranged on the light screen 1 Offset below, the offset ray is denoted as y ', is captured by a CCD sensor and y' -y is read out 1 This operation was repeated 2 times, and readings of a total of 3 offsets were recorded and averaged;
(6) Preparing a standard sample solution: selecting a proper concentration gradient of the transparent liquid, and calculating the mass of a sample required by the corresponding concentration; accurately weighing the mass of the sample in the weighing paper by using a balance; pouring the weighed sample into a beaker, and adding a small amount of distilled water to dissolve the sample; pouring the solution in the beaker into a volumetric flask, adding a small amount of distilled water into the beaker for cleaning, pouring the cleaning solution into the volumetric flask, repeating the operation for 3 times, dripping distilled water by using a rubber-tipped dropper to fix the volume of the solution in the volumetric flask to a constant volume, and uniformly mixing the solution in the volumetric flask;
(7) Actual offset value measurement: pouring a small amount of prepared solution into the triangular prism for rinsing for 2 to 3 times, and after rinsing, pouring the solution into the triangular prismAdding the prepared solution, pouring the solution to the prism, and controlling the volume of the solution to be half of that of the prism, wherein y is arranged on the light screen 1 The light ray with the deviation is marked as y 2 Taken by CCD sensor and read out y 2 -y 1 Repeat this operation 2 times, record readings of a total of 3 offsets and take the average;
(8) And fitting a concentration scale: repeating the steps (6) - (7) until the designed concentration gradient is measured, and fitting a relation between the concentration C and the offset y 2 -y 1 Making a concentration scale according to the fitted function;
(9) And measuring the sample deviation value: preparing a sample solution with unknown concentration as a to-be-tested solution of an experiment, pouring a small amount of to-be-tested sample solution into the triangular prism for 2 to 3 times of rinsing, adding the to-be-tested sample solution into the triangular prism after rinsing is finished, pouring the solution with the volume controlled to be half of the volume of the triangular prism, shooting by a CCD (charge coupled device) sensor, reading the value of y2-', repeating the operation for 2 times, recording readings of 3 offsets in total and taking an average value;
(10) And calculating the concentration of the sample: according to the distance y' between the offset of the distilled water and the initial position 1 And the distance y between the offset of the sample and the initial position can be obtained by subtracting the distance y 2-between the offset of the distilled water and the offset of the sample 2 - 1 And combining the fitted concentration scale to obtain the concentration of the sample.
Further, since during calibration, y is actual 2 Position of (a) and theory y 2 The positions of the scales are not completely consistent, and in order to improve the accuracy of measurement, the calibrated scales need to be calibrated correspondingly. And (4) measuring the solution with known concentration by using the calibrated solution concentration graduated scale, designing a plurality of sample concentration intervals, selecting 1 concentration in each interval to calibrate the concentration graduated scale in different intervals, repeating the steps (6) to (9), and obtaining a corresponding calibration value according to the actual value of the solution concentration and the measured value of the solution concentration.
Further, a sample solution with a known concentration is prepared, the concentration of the sample solution is measured through a concentration scale, data is recorded, an average value is calculated, corresponding solution concentration is measured, and corresponding measurement relative uncertainty and relative error are calculated.
Another aspect of the present invention is to protect a transparent solution concentration measuring apparatus based on a hollow triangular prism lens, wherein a hollow inner cavity of the hollow triangular prism lens forms a liquid containing cavity containing a transparent solution, and the liquid containing cavity comprises a light path forming unit and an image collecting unit; the light path forming unit comprises a machine-organ emitter, a convex lens and a hollow triangular prism lens which are arranged according to a light path, a light beam emitted by the machine-organ emitter is converted into a parallel light beam through the convex lens, and the parallel light beam can be correspondingly refracted after passing through the hollow triangular prism lens filled with the solution; the image acquisition unit comprises an optical screen arranged on the refraction light projection surface and a CCD sensor used for acquiring images of the optical screen, and the CCD sensor is electrically connected with the image acquisition card to acquire and store the images.
Further, the convex lens is disposed on a height-adjustable fixing frame.
Further, the hollow triangular prism lens is arranged on the horizontal table.
Further, the hollow triangular prism lens had dimensions of 41mm × 35.5mm × 49.8mm and a thickness of 2.491mm.
Furthermore, the laser emitter is a red light linear laser emitter, and the parameters of the laser emitter are 650nm and 5mV.
Furthermore, the model of the image acquisition card is MV-U2000.
Further, the focal length of the convex lens is 30cm.
The invention relates to a transparent solution concentration measuring device based on a hollow triangular prism lens, which has the following beneficial effects:
the invention provides a device for directly obtaining the concentration of a solution by measuring the deviation of refracted rays of a transparent liquid. The method adopts a parallel light source to irradiate a hollow triangular prism lens containing a solution, the refracted light rays generate corresponding deviation due to the fact that the refractive indexes of air and the solution are different, the deviation amount of the refracted light rays is measured, and the concentration of the liquid to be measured is determined according to the function relation between the deviation amount of the solution and the concentration of the solution. The device has the advantages of simple and quick measurement, capability of measuring the concentration of the solution in real time, small error of a measurement result, good repeatability and important application potential in the real-time dynamic measurement of the concentration of the transparent solution.
Drawings
FIG. 1 is a schematic composition diagram of a transparent solution concentration measuring device based on a hollow triangular prism lens according to the present invention;
FIG. 2 is a schematic diagram showing the relationship between the concentration of a solution and an offset when a hollow triangular prism lens is irradiated with parallel light;
FIG. 3 is a schematic view of an offset measurement;
FIG. 4 is a graph showing the relationship between the concentration of the transparent solution and the amount of shift;
FIG. 5 is a solution concentration scale in which (a) is a sodium chloride solution and (b) is a glucose solution;
FIG. 6 is a graph showing the measurement of the concentration of a clear solution, wherein (a) is a sodium chloride solution and (b) is a glucose solution;
the reference numbers in the drawings include: 1. a laser transmitter; 2. a convex lens; 3. a horizontal table; 4. a hollow triangular prism lens; 5. a light screen; 6. a CCD sensor.
Detailed Description
In order to make those skilled in the art better understand the technical solution of the present invention, the following detailed description will be made with reference to the embodiments and the accompanying drawings.
Another aspect of the present invention provides a method for directly deriving the concentration of a solution by measuring the amount of refraction shift of a transparent liquid. The method adopts a parallel light source to irradiate a hollow triangular prism lens containing a solution, the refracted light rays generate corresponding deviation due to the fact that the refractive indexes of air and the solution are different, the deviation amount of the refracted light rays is measured, and the concentration of the liquid to be measured is determined according to the function relation between the deviation amount of the solution and the concentration of the solution. The steps are as follows:
(1) A flat plastic plate or a wood plate or a metal plate is taken, a red light linear laser emitter, a convex lens, a horizontal table, a hollow triangular prism lens, a light screen (containing checkered paper) and specific positions for placing a CCD sensor are marked on the flat plastic plate or the wood plate or the metal plate, and the flat plastic plate or the wood plate or the metal plate is placed on a horizontal plane.
(2) The method comprises the following steps of taking the position of a red light linear laser emitter as a starting point, enabling a convex lens to be 30cm away from the red light linear laser emitter, enabling a horizontal table to be 10cm away from the convex lens, determining the position of a hollow triangular prism lens on the horizontal table, and installing a fixed support, enabling the light beam of the red light linear laser emitter to be parallel light beams after passing through the convex lens, enabling the parallel light beams to be correspondingly refracted after passing through the hollow triangular prism lens filled with a solution, enabling an optical screen to be 40cm away from the horizontal table, enabling the optical screen to move left and right, enabling the position of a CCD sensor to be unfixed and to be placed according to specific conditions, enabling the CCD sensor to be connected with a computer through an MV-U2000 image acquisition card, and enabling the positions of the red light linear laser emitter, the convex lens, the horizontal table and the hollow triangular prism lens to be located on a straight line.
(3) And adjusting the focal length and the brightness of the CCD sensor to ensure that the picture displayed by the CCD on a computer is clear.
(4) Starting a red light linear laser emitter, adjusting the parallel light beams passing through the convex lens to coincide with the longitudinal edge of the checkered paper in the light screen, and recording the position of the edge as y 1 。
(5) Pouring distilled water into the triple prism, controlling the volume of the poured solution to be half of the volume of the triple prism, wherein the triple prism must be placed at the same position, the position of each face of the triple prism cannot be changed, and at the moment, y is arranged on the light screen 1 The light ray with the deviation is marked as y 2 Is shot by CCD sensor and read out y 2 -y 1 Repeat this operation 2 times, record readings of a total of 3 offsets and take the average;
(6) Designing a proper transparent liquid concentration gradient, and calculating the sample mass required by the corresponding concentration; accurately weighing the sample mass in the weighing paper by using a high-sensitivity balance; pouring the weighed sample into a beaker, and adding a small amount of distilled water to dissolve the sample; pouring the solution in the beaker into a 100mL volumetric flask, adding a small amount of distilled water into the beaker for cleaning, pouring the cleaning solution into the volumetric flask, repeating the operation for 3 times, dripping distilled water by using a rubber dropper to fix the volume of the solution in the volumetric flask to 100mL, and uniformly mixing the solution in the volumetric flask. (7) Pouring a small amount of prepared solution into the triangular prism for rinsing2 to 3 times, after rinsing, adding the prepared solution into the triple prism, pouring the solution with the volume controlled to be half of the volume of the triple prism, and controlling the volume of the solution to be y on the light screen 1 The light ray with the deviation is marked as y 2 Is shot by CCD sensor and read out y 2 -y 1 This operation was repeated 2 times, and readings of 3 offsets were recorded and averaged in total, and the prism had to be placed at the same position, and the position of each face of the prism could not be changed.
(8) And (6) repeating the steps (6) to (7) until the designed concentration gradient is measured, and fitting a target concentration C and an offset y 2 -y 1 And (4) making a concentration scale according to the fitted function.
(9) Preparing a solution with unknown concentration as a solution to be tested for an experiment, pouring a small amount of sample solution to be tested into the prism for 2 to 3 times of rinsing, adding the sample solution to be tested into the prism after rinsing, pouring the solution with the volume controlled to be half of the volume of the prism, shooting by a CCD sensor, and reading y' -y 1 Repeat this operation 2 times, record readings of a total of 3 offsets and take the average;
(10) And a distance y' -y from the initial position according to the amount of the distilled water deviation 1 And the distance y of the offset of the distilled water and the offset of the sample 2 Y', the distance y between the sample offset and the initial position at the concentration of the liquid to be measured can be obtained 2 -y 1 And combining the fitted concentration scale to obtain the concentration of the sample.
Further, since during calibration, y is actual 2 Position of (a) and theory y 2 The positions of the scales are not completely consistent, and in order to improve the accuracy of measurement, the calibrated scales need to be calibrated correspondingly. And (4) measuring the solution with known concentration by using the calibrated solution concentration graduated scale, designing a plurality of sample concentration intervals, selecting 1 concentration in each interval to calibrate the concentration graduated scale in different intervals, repeating the steps (6) to (9), and obtaining a corresponding calibration value according to the actual value of the solution concentration and the measured value of the solution concentration.
Further, a sample solution with a known concentration is prepared, the concentration of the sample solution is measured through a concentration scale, data is recorded to calculate an average value, corresponding solution concentration is measured, and corresponding measurement relative uncertainty and relative error are calculated.
As shown in figure 1, the invention discloses a transparent solution concentration measuring device based on a hollow triangular prism lens.A hollow inner cavity of the hollow triangular prism lens 4 forms a liquid containing cavity containing transparent solution, and the liquid containing cavity comprises a light path forming unit and an image acquisition unit; the light path forming unit comprises a trap emitter 1, a convex lens 2 and a hollow triangular prism lens 4 which are arranged according to a light path, wherein a light beam emitted by the trap emitter 1 is converted into a parallel light beam through the convex lens 2, and the parallel light beam is correspondingly refracted after passing through the hollow triangular prism lens 4 filled with a solution; the image acquisition unit comprises a light screen 5 arranged on the refraction light projection surface and a CCD sensor 6 used for acquiring the image of the light screen, the CCD sensor 6 is electrically connected with the image acquisition card to realize the acquisition and storage of the image
Further, the convex lens is arranged on a fixed frame with adjustable height.
As shown in fig. 1, a hollow triangular prism lens 4 is disposed on a horizontal stage 3.
Further, the hollow triangular prism lens had dimensions of 41mm × 35.5mm × 49.8mm and a thickness of 2.491mm.
Furthermore, the laser emitter is a red light linear laser emitter, and the parameters of the laser emitter are 650nm and 5mV.
Furthermore, the model of the image acquisition card is MV-U2000.
Further, the focal length of the convex lens is 30cm.
The principle of the measuring device of the invention is as follows:
from the empirical formula of the relationship between the solution concentration and the refractive index, it can be known that the refractive index of the solution increases with the increase of the solution concentration, and the refractive index n of the liquid and the concentration C of the liquid are in a linear relationship, and the functional relationship can be expressed as:
n=a+bC (1)
a and b are constants associated with the instrument used.
In the present invention, the relationship between the concentration of the solution and the amount of deviation when the hollow triangular prism lens is irradiated with parallel light is as followsAs shown in fig. 2, when a beam of parallel light enters the prism containing the solution, the refracted light deviates from the original light path and generates a certain offset. The emergent light has a deflection angle delta relative to the incident light, and the minimum deflection angle delta min The relationship between the refractive index n of the solution and the prism apex angle α is:
when the deflection angle is changed, the offset on the light screen is changed, and the offset y 2 -y 1 Satisfies the following conditions with the deflection angle:
y 2 -y 1 =L tanδ min (3)
y 1 for the non-deflected position of the parallel light, y 2 The position where the parallel light is deflected and L is the distance from the exit point to the light screen, it can be seen from equation (2) that when the refractive index n increases, δ min And also increases. y = tan δ is a monotonically increasing function, and when δ is found in formula (3) min At increasing time, y 2 -y 1 And also increases. Let the amount of change in deflection angle due to a change in concentration be θ:
θ=δ min -δ 0 (4)
δ 0 in the case of a deflection angle of C =0, the concentration C and the deflection angle change amount θ satisfy:
C=aθ-b (5)
a and b are constants associated with the instrument used. When the refractive index n increases, δ min Increasing theta increases therewith; from the formula (5), the solution concentration increases as θ increases. Since the amount of shift is related to the refractive index and the refractive index is related to the concentration, the amount of shift y 2 -y 1 And the concentration C satisfies:
due to the fact thatWhen delta is caused by concentration min When uniformly changed, it corresponds toThe solution concentration is a linear function of the amount of shift, since it varies uniformly in synchronism, as can be seen from equation (6).
The measurement of the amount of refracted ray deviation is the key to the present invention. When the hollow triangular prism lens is filled with the solution, the height of the solution is about half of that of the hollow triangular prism lens, the lower half part of the solution is the solution, and the upper half part of the solution is the air. As shown in FIG. 3, for the upper part of air, the refractive index of the light in the air is 1, and the position of the light screen projected by the parallel light through the air at the upper half part of the hollow triangular prism lens is y 1 . For the lower part of the solution (e.g. clear water, concentration C) 0 In terms of the light screen, the refractive index of the clean water is not 1, so that the position of the same beam of parallel light projected on the light screen by the clean water passing through the lower half part of the hollow triangular prism lens is y'. When the measured solution concentrations are different (e.g. sodium chloride solution, concentration C) 1 In the meantime), the refractive index of the solution is different from that of clear water, and the position of the projection of the parallel light rays on the light screen through the solution at the lower half part of the hollow triangular prism lens is y 2 . Since the view range of the CCD sensor is limited, in order to ensure the measurement accuracy, the view unit area of the CCD sensor should contain the largest number of pixels, and therefore, as shown in fig. 3, the dashed square box is the shooting range of the CCD sensor during the measurement operation. During measurement, the position of the CCD sensor is adjusted to ensure that y' is a reference line in the view range of the CCD sensor on the light screen, and a precision steel ruler is used for measuring y 1 Distance y' -y to y 1 For y 'and y' in the view range of the CCD sensor 2 Distance y therebetween 2 -y', accurate measurements can be made. From y' -y 1 And y 2 -y' available y 1 To y 2 Distance y therebetween 2 -y 1 。
The following describes a measurement process and method for measuring the concentration of a transparent liquid based on a hollow triangular prism lens, taking a sodium chloride solution and a glucose solution as examples.
And researching the rule between the concentration of the transparent solution and the offset, and determining the functional relation between the concentration of the transparent solution and the offset. 20 sets of sodium chloride solutions with different concentrations and 15 sets of glucose solutions with different concentrations were prepared, and the offset was measured at different solution concentrations. As shown in FIGS. 4 (a) and (b), the amounts of shift increase monotonically with the increase in the concentration of the clear solution for both the sodium chloride solution and the glucose solution, and the concentration of the clear solution has a clear linear relationship with the amount of shift. Further, the measurements in FIG. 4 were fitted and the concentration of the clear solution was determined as a function of the amount of shift. For sodium chloride solutions, the measurements are uniformly distributed around the fitted curve, which is a binary first-order function: y is 2 -y 1 =0.5349C +12.18471, wherein R 2 =0.99, close to 1, means a high degree of linearity. For glucose solutions, all measurements were on the fitted curve, and the fitted binary linear function was: y is 2 -y 1 =1.24739C +12.36975, wherein R 2 =1, means that the degree of linearity is high, and the concentration C and offset y of the available sodium chloride solution and glucose solution 2 -y 1 With a linear relationship, these measurements are consistent with the inference of equation (6).
According to the functional relationship between the solution concentration and the offset of the sodium chloride solution and the glucose solution, a series of different solution concentrations (such as 0.25mol/L,0.50mol/L,0.75mol/L,1.00mol/L and the like) along with corresponding theoretical values of the deviation of the refracted ray can be determined, and a corresponding concentration scale can be obtained by calibrating on an optical screen according to the theoretical values of the deviation of the refracted ray.
As shown in fig. 5, for the same group of solutions, the scales in the concentration scale are uniform, and the offset amount is uniformly increased along with the uniform increase of the concentration; however, the solution concentration graduated scales of different groups of solutions are inconsistent, and the offset synchronously changes by 0.027cm along with the change of the sodium chloride concentration by 0.05 mol/L; with a 0.05mol/L change in glucose concentration, the offset also changed synchronously by 0.063cm.
Furthermore, since during calibration, y is actually 2 Position of (a) and theory y 2 In order to improve the measurementThe accuracy of the measurement needs to be calibrated correspondingly to the calibrated scale. Measuring the solution with known concentration by using a calibrated solution concentration graduated scale according to the actual value C of the solution concentration Actual value With measured value C of solution concentration Measured value The corresponding calibration value C can be obtained Calibration value :
C Calibration value =C Actual value -C Measured value (7)
As shown in tables 1 and 2, the sodium chloride solution and the glucose solution had an average calibration value of 0.02mol/L and 0.01mol/L. Therefore, the calibrated solution concentration graduated scale is adopted to measure the concentration, and more accurate measurement data can be obtained.
TABLE 1 calibration values for sodium chloride solution concentration scales
TABLE 2 calibration values for glucose solution concentration scales
Randomly selecting a group of sodium chloride solution to be detected and glucose solution to be detected with unknown concentration, respectively measuring for 10 times, recording the offset by using a CCD (charge coupled device), and determining the measured value of the concentration of the solution to be detected by using a calibrated solution concentration graduated scale. The measured data are shown in fig. 6, and the measured values are distributed around the actual values. For a sodium chloride solution with the actual concentration of 1.87mol/L, the measurement data of 10 groups are in the range of 1.84mol/L to 1.90mol/L, the measurement average value is 1.86mol/L, the measurement relative error is 0.6 percent, and the measurement result obtained by calculation is (1.86 +/-0.04) mol/L; for the glucose solution with actual concentration of 0.65mol/L, 10 groups of measurement data range from 0.64mol/L to 0.67mol/L, and the measurement average value is: 0.66mol/L, the relative error of measurement is 1.6%, the measurement result obtained by calculation is (0.66 +/-0.04) mol/L, the measurement result shows that the error of measuring the concentration of the solution by using the hollow triangular prism is small, the repeatability is good, and the measurement of the concentration of the transparent liquid by using the hollow triangular prism lens is feasible.
The measuring device for measuring the concentration of the solution by using the hollow prism determines the linear relation between the offset of the refracted ray and the concentration of the solution to be measured by shooting and measuring the offset of the refracted ray through the CCD, and calibrates the corresponding solution concentration graduated scale. Random measurement is carried out on the sodium chloride solution with the actual concentration of 1.87mol/L, and the result is (1.86 +/-0.04) mol/L; the glucose solution with the actual concentration of 0.65mol/L was randomly measured, and the result was (0.66. + -. 0.04) mol/L. The error of measuring the concentration of the solution by using the hollow triangular prism is small, the repeatability is good, and the method has important application potential in real-time dynamic measurement of the concentration of the transparent solution.
The above embodiments are only specific embodiments of the present invention, and the description thereof is specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that various changes and modifications as would be obvious to one having the ordinary skill in this art may be made without departing from the spirit and scope of the invention, and such obvious alternatives are intended to be included within the scope of the invention.
Claims (10)
1. A transparent solution concentration measuring method based on a hollow triangular prism lens is characterized by comprising the following steps:
(1) And positioning identification: the specific positions of a laser emitter, a convex lens, a horizontal table, a hollow triangular prism lens, an optical screen (containing checkered paper) and a CCD sensor are marked on the horizontal plate table and are placed on a horizontal plane;
(2) And assembling the device: the method comprises the following steps that the position of a laser emitter is taken as an initial point, a convex lens is arranged away from the laser emitter, a horizontal table is arranged at the other side away from the convex lens, the position where a hollow triangular prism lens is arranged is determined on the horizontal table, a fixing support is arranged, so that a light beam of the laser emitter is converted into a parallel light beam through the convex lens, the parallel light beam can correspondingly refract after passing through the hollow triangular prism lens filled with solution, an optical screen capable of moving left and right is arranged away from the horizontal table, a CCD sensor is not fixed in the position and can be arranged according to specific conditions, and the CCD sensor is connected through an image acquisition card to acquire and store data;
(3) And adjusting the CCD sensor: adjusting the focal length and the brightness of the CCD sensor to enable the picture displayed by the CCD on a computer to be clear;
(4) And measuring an initial position: starting the laser emitter, adjusting the parallel light beams passing through the convex lens to coincide with the longitudinal edge of the checkered paper in the light screen, and recording the position of the edge as y 1 ;
(5) And measuring a theoretical offset position: distilled water is poured into the triangular prism, the volume of the poured solution is controlled to be half of the volume of the triangular prism, the triangular prism must be placed at the same position, the position of each face of the triangular prism cannot be changed, and at the moment, y is arranged on the light screen 1 The light beam is shifted to y 'below, and is captured by CCD sensor to read out y' -y 1 This operation was repeated 2 times, and readings of a total of 3 offsets were recorded and averaged;
(6) Preparing a standard sample solution: selecting a proper concentration gradient of the transparent liquid, and calculating the mass of a sample required by the corresponding concentration; accurately weighing the sample mass in the weighing paper by using a balance; pouring the weighed sample into a beaker, and adding a small amount of distilled water to dissolve the sample; pouring the solution in the beaker into a volumetric flask, adding a small amount of distilled water into the beaker for cleaning, pouring the cleaning solution into the volumetric flask, repeating the operation for 3 times, dripping distilled water by using a rubber-tipped dropper to fix the volume of the solution in the volumetric flask to a constant volume, and uniformly mixing the solution in the volumetric flask;
(7) Actual offset value measurement: pouring a small amount of prepared solution into the triple prism for rinsing for 2-3 times, adding the prepared solution into the triple prism after rinsing, pouring the solution with a volume controlled to be half of that of the triple prism, and then, y is arranged on the light screen 1 The light ray with the deviation is marked as y 2 Is shot by CCD sensor and read out y 2 -y 1 Repeat this operation 2 times, record readings of a total of 3 offsets and take the average;
(8) And fitting a concentration scale: repeating the steps (6) - (7) until the designed concentration gradient is measured, and fitting a relation between the concentration C and the offset y 2 -y 1 As a function of (a) or (b),manufacturing a concentration scale according to the fitted function;
(9) And measuring the sample deviation value: preparing a solution with unknown concentration as a solution to be tested, pouring a small amount of sample solution to be tested into the triple prism for 2-3 times, adding the sample solution to be tested into the triple prism after the rinsing is finished, pouring the solution with a volume controlled to be half of the volume of the triple prism, shooting by a CCD sensor, and reading y 2 -y 1 This operation was repeated 2 times, and readings of a total of 3 offsets were recorded and averaged;
(10) And calculating the concentration of the sample: y is 1 As starting point, based on the distance y' -y of the offset of the distilled water from the initial position 1 And the distance y of the offset of the distilled water and the offset of the sample 2 Y' add up to the distance y between the sample offset and the initial position 2 -y 1 And combining the fitted concentration scale to obtain the concentration of the sample.
2. The method for measuring concentration of transparent solution based on hollow triangular prism lens according to claim 1, wherein: further comprising a calibration step: and (3) measuring the solution with known concentration by using the calibrated solution concentration graduated scale, designing a plurality of sample concentration intervals, selecting 1 concentration in each interval to calibrate the concentration graduated scale in different intervals, repeating the steps (6) to (9), and obtaining a corresponding calibration value according to the actual value of the solution concentration and the measured value of the solution concentration.
3. The method for measuring the concentration of a transparent solution based on a hollow triangular prism lens according to claim 1, wherein: further comprising the step of uncertainty measurement: preparing a sample solution with known concentration, measuring the concentration of the sample solution through a concentration scale, recording data, calculating an average value, measuring the corresponding solution concentration, and calculating to obtain the corresponding measurement relative uncertainty and relative error.
4. A measuring device used in the method for measuring the concentration of a transparent solution based on a hollow triangular prism lens according to any one of claims 1 to 3, wherein: comprises an optical path forming unit and an image acquisition unit; the light path forming unit comprises a machine-organ emitter, a convex lens and a hollow triangular prism lens which are arranged according to a light path, a light beam emitted by the machine-organ emitter is converted into a parallel light beam through the convex lens, and the parallel light beam can be correspondingly refracted after passing through the hollow triangular prism lens filled with the solution; the image acquisition unit is including being used for setting up the light screen at refraction light projection plane and being used for gathering the CCD sensor of light screen image, the CCD sensor is connected the collection and the storage that realize the image with the image acquisition card electricity.
5. The transparent solution concentration measuring device based on the hollow triangular prism lens according to claim 1, wherein: the convex lens is arranged on the fixing frame with adjustable height.
6. The transparent solution concentration measuring device based on the hollow triangular prism lens according to claim 2, wherein: the hollow triangular prism lens is arranged on the horizontal table.
7. The transparent solution concentration measuring device based on the hollow triangular prism lens according to claim 3, wherein: the hollow triangular prism lens has the dimensions of 41mm multiplied by 35.5mm multiplied by 49.8mm and the thickness of 2.491mm.
8. The transparent solution concentration measuring device based on the hollow triangular prism lens according to claim 7, wherein: the laser emitter is a red light linear laser emitter, and the parameters of the laser emitter are 650nm and 5mV.
9. The transparent solution concentration measuring device based on the hollow triangular prism lens according to claim 8, wherein: the model of the image acquisition card is MV-U2000.
10. The transparent solution concentration measuring device based on the hollow triangular prism lens according to claim 9, wherein: the focal length of the convex lens is 30cm.
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