A desktop turbidimeter and a water quality detection method

Abstract

The present invention relates to the technical field of turbidimeters, and discloses a desktop turbidimeter and a water quality detection method. The desktop turbidimeter includes an optical path module, and the optical path module includes a light source module, a sample detection position and a sensor module. The sensor module includes a transmitted light sensor and a scattered light sensor. The optical axis of the light source module passes through the transmitted light sensor. At least two groups of scattered light sensors are provided, namely a first scattered light sensor and a second scattered light sensor. During detection, each scattered light sensor receives scattered light at different heights. In this solution, by setting scattered light sensors in the optical path module, and at least two groups are provided, and the two groups of scattered light sensors are distributed at different heights, scattered light signals at different heights can be received, and then the reasons for unstable turbidity, such as sedimentation or disturbance, can be judged according to the scattered light signals at different heights, so that users can timely eliminate the problems existing in the water sample and obtain more reliable and accurate detection results.

Description

Technical Field

[0001] The invention relates to the technical field of turbidity meters, in particular to a desktop turbidity meter and a water quality detection method. Background Art

[0002] Water turbidity is one of the important indicators to measure the cleanliness of water. By measuring the turbidity of water, impurities and pollutants in water can be found in time, changes in water quality can be found in time, and the adjustment and optimization of water treatment processes can be guided, the quality of effluent can be improved, people can be prevented from drinking harmful substances, and people's health can be protected. Therefore, monitoring water turbidity is of great significance for protecting people's health, guiding water treatment, evaluating water quality and ecological protection.

[0003] There are many instruments that can monitor the turbidity index of water quality. According to different occasions of use, they can be roughly divided into three categories: portable turbidity meters, online monitoring turbidity meters, and desktop turbidity meters. Among them, the range, accuracy, and repeatability of desktop turbidity meters are the best. Desktop turbidity meters are widely used in laboratories. When different types of turbidity meters have measurement errors, the data of desktop turbidity meters are often used as the judgment standard.

[0004] When a desktop turbidity meter is used to test water quality, if there is disturbance and sedimentation in the water sample, it will affect the test results. However, the commonly used turbidity meters currently have difficulty in judging whether there is disturbance or sedimentation in the water sample during the test process, and it is also difficult to process the water sample in a targeted manner, which leads to the problem that subsequent test results are easily distorted. In response to the above problems, this application is proposed. Summary of the invention

[0005] The purpose of the present invention is to provide a desktop turbidity meter and a water quality detection method, which are used to overcome the problem that the existing desktop turbidity meter is difficult to judge the state of water samples, thereby making it difficult to obtain accurate and reliable detection results.

[0006] The present invention is achieved through the following technical solutions.

[0007] A bench-top turbidimeter of the present invention is mainly characterized in that at least two sensors are arranged vertically on the side of the colorimetric bottle for testing water samples, and the measured values of multiple sensors are used to evaluate the stability of the water samples, so as to judge whether there are disturbances and sedimentation problems in the water samples, assist in the timely elimination of problems, and thus obtain more accurate detection results. The bench-top turbidimeter specifically includes an optical path module, and the optical path module includes a light source module, a sample detection position and a sensor module. The sample detection position is used to place the water sample to be detected, and the sensor module is arranged around the sample detection position. The sensor module includes a transmitted light sensor and a scattered light sensor. The optical axis of the light source module passes through the transmitted light sensor. At least two groups of scattered light sensors are provided, namely a first scattered light sensor and a second scattered light sensor. The first scattered light sensor and the second scattered light sensor are arranged on the side of the optical axis, which is also the side of the sample detection position, and are arranged in sequence in the height direction, that is, one is higher and the other is lower. During detection, each of the scattered light sensors receives scattered light at different heights.

[0008] Further, the scattered light sensor is arranged at a 90° angle to the optical axis.

[0009] Further, the installation heights of the first scattered light sensor and the second scattered light sensor are respectively set higher and lower than the height of the optical axis, and preferably are symmetrically arranged on the upper and lower sides of the optical axis with the optical axis as the center.

[0010] Further, the scattered light sensor further includes a third scattered light sensor and a fourth scattered light sensor, and the third scattered light sensor and the fourth scattered light sensor are arranged opposite to the first scattered light sensor and the second scattered light sensor, that is, are respectively arranged on both sides of the water sample to be detected.

[0011] Optionally, when it is necessary to further improve the accuracy of the detection result, the number of scattered light sensors can be increased to more than four groups.

[0012] Further, the transmitted light sensor is installed obliquely to reflect the light reaching the transmitted light sensor to the side wall, avoiding the reflected light returning along the original path and reducing stray light. Preferably, it is installed at an angle of 45°.

[0013] Further, the bench-top turbidimeter further includes a housing assembly, and a touch display screen is arranged on the housing assembly. The touch display screen can be used to display information such as detection parameters and steps, as well as control operations such as the progress of detection, which can bring a better operation experience.

[0014] Further, the light source module includes a light-shielding cover, a light source, a focusing lens assembly and a diaphragm. The light source is installed in the light-shielding cover, and the light source, the focusing lens assembly and the diaphragm are coaxially installed. The diaphragm is a light-blocking sheet with a circular hole in the center. There is at least one light-blocking sheet for the diaphragm, and at least one lens is provided for the focusing lens assembly.

[0015] Furthermore, the desktop turbidimeter further includes a heat dissipation mechanism for dissipating heat from the light source module, and the heat dissipation mechanism can be configured as a heat dissipation fan, heat dissipation fins, a heat pipe heat dissipation structure, etc.

[0016] A water quality detection method, based on the above desktop turbidimeter, includes the following steps:

[0017] Signal receiving step:

[0018] Place the water sample at the sample detection position;

[0019] Turn on the light source module, the light beam passes through the water sample, and the transmitted light sensor arranged behind the water sample is used to receive the transmitted light signal , and at least two scattered light sensors at different heights arranged on the side of the water sample are used to receive the scattered light signals at the upper position and the scattered light signals at the lower position ;

[0020] Stability evaluation step:

[0021] When , it is determined that the signal is stable, and the turbidity value calculation step is executed;

[0022] When , it is determined that there is a sedimentation problem with the water sample, and after performing the action of shaking evenly, measure again;

[0023] When , and , it is determined that there is a disturbance problem with the water sample, and the static step is executed, and after standing for a set time, measure again;

[0024] When it is determined that there is a problem with the water sample, the user can be reminded by displaying on the screen or emitting sound and light;

[0025] Turbidity value calculation step:

[0026] According to the theory of turbidity, the ratio of scattered light to transmitted light is proportional to turbidity. Therefore, using the data determined to be stable, the scattered light signals of two or four or several 90° sensors are averaged, and then the ratio to the 180° transmitted light signal is obtained. By measuring this data, the turbidity of the sample can be calculated; taking the two scattered light signals as an example, the calculation formula is: , and the turbidity of the sample can be calculated by measuring this data.

[0027] Furthermore, in the above steps, set , .

[0028] Advantages of the present invention: In this solution, by setting scattering light sensors in the optical path module, with at least two groups, and the two groups of scattering light sensors being distributed at different heights, scattered light signals at different heights can be received. Then, based on the scattered light signals at different heights, the reasons causing turbidity instability, such as sedimentation or disturbance, can be judged, enabling users to timely eliminate problems existing in the water sample and obtain more reliable and accurate detection results.

[0029] Moreover, when calculating turbidity, averaging the measurements of multiple 90° scattered signals is beneficial to data stability, reducing the influence of the difference in cuvettes on turbidity and the influence of water sample fluctuations on turbidity. Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0031] The present invention will be further described below in conjunction with the drawings and embodiments.

[0032] Figure 1 It is a schematic diagram of the overall structure of a bench-top turbidimeter;

[0033] Figure 2 It is a schematic diagram of the overall structure of the bench-top turbidimeter after opening the cover;

[0034] Figure 3 It is a rear view of the bench-top turbidimeter;

[0035] Figure 4 It is a schematic diagram of the bench-top turbidimeter disassembled and exploded;

[0036] Figure 5 It is a schematic diagram of the optical path module disassembled and exploded;

[0037] Figure 6 It is a schematic diagram of the optical path module;

[0038] Figure 7 It is an optical path schematic diagram;

[0039] Figure 8 It is a schematic diagram of the optical path module in Embodiment 2;

[0040] Figure 9 It is a top view of the optical path module in Embodiment 2;

[0041] Figure 10 It is a schematic diagram of the relationship between the sedimentation threshold, the disturbance threshold, and the water sample state. Detailed Embodiments

[0042] The following will Figures 1 - 10 describe the present invention in detail.

[0043] Embodiment 1:

[0044] A desktop turbidimeter of the present invention includes a housing assembly and an optical path module 2.

[0045] As Figures 1 - 4 , the housing assembly includes an upper housing 1 and a lower housing 3. The upper and lower housings are modularly designed, with a simple and stable structure.

[0046] The upper housing 1 is provided with a front acrylic plate 11, a front groove 12, a measuring groove light-shielding cover 13, an upper acrylic plate 14, a touch display screen 15, an upper groove 16, an instrument switch 17, a switch installation groove 18, and a display screen installation groove 19; the front acrylic plate 11 is installed at the front groove 12 for instrument identification display; the front acrylic plate 14 is installed at the upper groove 16, also for instrument identification display; the instrument switch 17 is installed in the switch installation groove 18; the touch display screen 15 is installed in the display screen installation groove 19.

[0047] The lower housing 3 is provided with an optical path installation boss 31, a control circuit board 32, a rear cover 33, and a rear heat dissipation plate 34; the rear cover 33 is provided with an instrument nameplate installation area 331, a circuit board interface 332, and an antenna 333; the circuit board interface 332 is provided with interfaces such as power supply and communication; there is at least one antenna 333 for wireless signal connection such as 4G, WIFI, and Bluetooth, and the data can be uploaded to the data center after the measurement is completed.

[0048] As Figures 5 - 7 , the optical path module 2 includes an optical path upper cover 23, a bottom plate 24, a light source module 25, and a positioning post 26.

[0049] The top of the optical path upper cover 23 is provided with a colorimetric bottle socket 231. During measurement, the colorimetric bottle 22 is inserted from the colorimetric bottle socket to the sample detection position 27; one end of the optical path upper cover 23 is provided with a light incident hole 232, and the light emitted by the light source module 25 is incident into the optical measurement system installed on the bottom plate 24 from the light incident hole 232. The positioning post 26 is used to assist in the positioning and installation of the optical path upper cover 23 and the bottom plate 24.

[0050] The light source module 25 is provided with a light-shielding cover 251, a light source fixing seat 253, and a light source 254. The bottom of the light-shielding cover 251 is provided with heat dissipation holes 252. The light source 254 is installed on the light source fixing seat 253 and then installed in the light-shielding cover 251 together with the light source fixing seat 253 to complete the assembly of the light source module 25. The light source module 25 is installed on the bottom plate 24.

[0051] The heat dissipation holes 252 and the rear heat dissipation plate 34 constitute a heat dissipation mechanism.

[0052] A focusing lens assembly 241 and a lens mounting seat 242 are provided on the bottom plate 24. The focusing lens assembly 241 is provided with at least one lens, which is installed inside the lens mounting seat 242, and the lens mounting seat 242 is installed on the bottom plate 24.

[0053] The diaphragm 243 is a light-shielding sheet with a circular hole in the center. The diaphragm 243 has at least one light-shielding sheet and is installed on the bottom plate 24.

[0054] The 90° scattered light sensor fixing seat 244 is provided with a first light-transmitting window 2441 and a second light-transmitting window 2442. The first scattered light sensor 2443 is installed at the position of the first light-transmitting window 2441, and the second scattered light sensor 2444 is installed at the position of the second light-transmitting window 2442. The 90° scattered light sensor fixing seat 244 is installed on the bottom plate 24.

[0055] The transmitted light sensor 246 is installed on the 180° transmitted light sensor fixing seat 247; the 180° transmitted light sensor fixing seat 247 is installed on the bottom plate 24.

[0056] The light source 254, the light inlet hole 232, the focusing lens assembly 241, and the diaphragm 243 are coaxially installed, and their centers are on the same horizontal line. The center of the 180° transmitted light sensor fixing seat 247 is aligned with the above optical path, and the installation angle is 45°. The light reaching the transmitted light sensor is reflected to the side wall to avoid the reflected light returning along the original path and reduce stray light.

[0057] The 90° scattered light sensor fixing seat 244 is installed on the side of the colorimetric bottle 22, forming a 90° angle with the above optical axis to receive the 90° scattered signal.

[0058] During detection, ideally, if the water sample is stable and meets the turbidity measurement requirements, the optical signals reaching the two scattered light sensors travel the same distance, and the measurement values of the two scattered light sensors are similar; when the suspended matter particles in the water sample are disturbed, the signals of the two sensors will be different. The degree of disturbance of the water sample can be obtained by evaluating the difference in the signals of the two scattered light sensors; when there is precipitation of suspended matter particles in the water sample, the signal of the lower sensor will be larger than that of the upper sensor. The degree of precipitation of the water sample can be evaluated by evaluating the signal ratio of the upper and lower sensors; for the situations of disturbance and precipitation in the water sample, different measures need to be taken respectively. When there is disturbance, it is necessary to wait for the water sample to stabilize; when there is precipitation, it is necessary to shake the water sample to make it more uniform, so as to timely eliminate the problems existing in the water sample and obtain more reliable and accurate detection results.

[0059] Embodiment 2:

[0060] Based on Embodiment 1, as Figure 8, a second 90° scattered light sensor fixing base 245 is mirror - set opposite to the 90° scattered light sensor fixing base 244. A third light - transmitting window 2451, a fourth light - transmitting window 2452 are provided on the second 90° scattered light sensor fixing base 245. A third scattered light sensor 2453 is installed at the position of the third light - transmitting window 2451, and a fourth scattered light sensor 2454 is installed at the position of the fourth light - transmitting window 2452.

[0061] In this embodiment, four 90° scattered light signals can be obtained in one measurement, which are the signals of the first scattered light sensor 2443 , the signals of the second scattered light sensor 2444 , which are the signals of the third scattered light sensor 2453 , and the signals of the fourth scattered light sensor 2454 .

[0062] By judging the four 90° scattered signals, the stability evaluation will be more accurate; by calculating the average of the four 90° scattered signals, the turbidity data will also be more accurate.

[0063] An embodiment 1 of a water quality detection method, based on the desktop turbidimeter in any of the above - mentioned embodiments, includes the following steps:

[0064] Step 1: Receive signals. The light beam emitted by the light source 254 becomes a focused light beam after passing through the focusing lens assembly 241. The focused light beam passes through the colorimetric bottle 22. During the transmission process, when encountering the turbidity and suspended matter particles in the water sample in the colorimetric bottle 22, it will be absorbed and scattered. The transmitted light sensor 246 arranged behind the colorimetric bottle 22 receives the 180° transmitted light signal , the first scattered light sensor 2443 arranged on the side of the colorimetric bottle 22 receives the scattered light at a position slightly above the center of the colorimetric bottle 22 , the second scattered light sensor 2444 arranged on the side of the colorimetric bottle 22 receives the scattered light at a position slightly below the center of the colorimetric bottle 22 ;

[0065] According to the turbidity scattering theory, ;

[0066] ;

[0067] ;

[0068] In the formula, is the luminous intensity of the incident light, K is a proportionality constant, T is the turbidity, is the optical path of the transmitted light, usually the diameter of the colorimetric bottle; is the absorption related to the scattering function coefficient; is the number of particles contained in the water sample above the center of the colorimetric bottle; is the number of particles contained in the water sample below the center of the colorimetric bottle; is the optical path of the first scattered light sensor reaching above the center of the colorimetric bottle, is the optical path of the second scattered light sensor reaching below the center of the colorimetric bottle. Since the first scattered light sensor and the second scattered light sensor are arranged symmetrically above and below the center of the colorimetric bottle, the optical paths are the same, that is ;

[0069] Therefore, the difference in the number of particles above and below the colorimetric bottle 、 will cause differences in and .

[0070] When the turbidity distribution is uniform, , so ;

[0071] When the turbidity distribution is non-uniform, , so ;

[0072] Step 2, Stability evaluation. Suspended matter particles in the actual water sample inevitably have disturbances and sedimentation phenomena. Different measures need to be taken for turbidity measurement errors caused by different reasons. The method of this patent can judge the reasons for the errors. Specifically, the signal ratio of the first scattered light sensor 2443 and the second scattered light sensor 2444 is used to judge the stability:

[0073] When , the signal is considered stable, the turbidity particle distribution is uniform, and the turbidity data is true and reliable;

[0074] When , it is necessary to further judge whether it is caused by the disturbance or sedimentation of the water sample. When the water sample sediments, there are more particles in the lower position of the colorimetric bottle than in the upper position, that is , judge whether it is caused by sedimentation, that is, continue to judge if , it is considered that there is sedimentation; usually , so:

[0075] When , it can be considered that there is sedimentation, and the user is reminded to shake the water sample evenly before use;

[0076] When , and , it is considered that the water sample has disturbances and needs to be left standing for a while before measuring again;

[0077] Step 3: Turbidity value calculation. According to the theory of turbidity, the ratio of scattered light to incident light is proportional to turbidity. Therefore, the signals of the two 90° sensors can be averaged and then compared with the 180° signal to obtain data , and the turbidity of the sample can be calculated by measuring this data.

[0078] The disturbance threshold and sedimentation threshold are set as Figure 10 shown below:

[0079] It is set that when , that is, when the particles below the center of the colorimetric bottle are about twice as many as those below the center, that is, when , it is considered that there is a sedimentation phenomenon at this time, and the water sample needs to be shaken and then measured;

[0080] When the water sample is shaken at time t1, the upper and lower particles in the colorimetric bottle are mixed and exchanged with each other, and the particulate matter flutters in the whole bottle, forming a disturbance signal. When the particulate matter flutters in the whole bottle, the upper and lower particles in the colorimetric bottle are not much different, that is and are not much different, but the fluttering of the particulate matter will cause signal disturbance, and it will gradually tend to be stable as time increases, as shown from time t1 to t2 in the figure; at this time , taking the absolute value here is because of the fluttering of the particles, and there may be a situation of , and taking the absolute value is more convenient for calculation. But because the upper and lower particulate matters are not much different, .

[0081] Set , that is, the difference between the particulate matter above and below the center of the colorimetric bottle ( ) is within 95%, which is considered stable. As shown in the figure when reaching time t2, at this time , the signal is stable at this time, and the disturbance of the water sample in the colorimetric bottle is small and there is no sedimentation, which is suitable for turbidity measurement.

[0082] Example 2 of a water quality detection method: It further includes the following steps: when it is determined that there is a problem with the water sample, the user can be reminded by displaying on the screen or emitting sound and light.

[0083] Preferably, a shaking mechanism, such as a crank-rocker mechanism, a cam mechanism, etc., can be provided at the sample detection position 27, which can shake the colorimetric bottle 22. When it is determined that there is a sedimentation phenomenon, the shaking mechanism receives the shaking instruction sent by the control module and shakes the colorimetric bottle 22. The shaking time and the standing time are in a proportional relationship with the sedimentation and disturbance degree of the water sample.

[0084] The above embodiments are only for illustrating the technical concept and features of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it, and it should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.

Claims

1. A water quality detection method, characterized in that: The detection is carried out using a desktop turbidity meter, the desktop turbidity meter comprising an optical path module (2), the optical path module (2) comprising a light source module (25), a sample detection position (27) and a sensor module, the sample detection position (27) being used to place a water sample to be detected, the sensor module comprising a transmitted light sensor (246) and a scattered light sensor, the optical axis of the light source module (25) passing through the transmitted light sensor (246), at least two groups of the scattered light sensors being provided, namely a first scattered light sensor (2443) and a second scattered light sensor (2444), the first scattered light sensor (2443) and the second scattered light sensor (2444) being provided on the side of the optical axis and being arranged in sequence in the height direction, and during detection, each of the scattered light sensors receives scattered light at a different height; the first scattered light sensor (2443) and the second scattered light sensor (2444) are provided at a height higher than the optical axis and a height lower than the optical axis, respectively, and the scattered light sensors are arranged at 90 degrees to the optical axis; The water quality testing method includes the following steps: Steps to receive signal: Place the water sample at the sample detection position (27); The light source module (25) is turned on, the light beam passes through the water sample, and the transmitted light signal is received by the transmitted light sensor (246) arranged behind the water sample. At least two scattered light sensors at different heights are arranged on the side of the water sample to receive scattered light signals at the upper position respectively. and the scattered light signal at the lower position ; Stability assessment steps: when When , the signal is determined to be stable, and the turbidity value calculation step is executed; when When the water sample is shaken evenly, it is judged that there is a sedimentation problem, and the water sample is measured again; When the water sample is shaken, the upper and lower particles in the water sample mix and exchange with each other, and the particles float in the entire water sample, forming a disturbance signal. When the particles float in the entire water sample, the upper and lower particles in the water sample are almost the same, but the floating of the particles will cause signal disturbance, so when ,and When the water sample is disturbed, it is determined that the water sample has a disturbance problem, and the static step is performed. After the static step lasts for a set time, the water sample is measured again. Turbidity value calculation steps: using the data determined as stable signals, calculate the ratio of the average value of at least two scattered light signals to the transmitted light signal, the calculation method is: By measuring this data, the turbidity of the water sample can be calculated.

2. The water quality detection method according to claim 1, characterized in that: The scattered light sensor further comprises a third scattered light sensor (2453) and a fourth scattered light sensor (2454), wherein the third scattered light sensor (2453) and the fourth scattered light sensor (2454) are arranged opposite to the first scattered light sensor (2443) and the second scattered light sensor (2444).

3. The water quality detection method according to claim 1, characterized in that: The transmission light sensor (246) is installed at an angle, and is used to reflect light reaching the transmission light sensor (246) to the side wall.

4. The water quality detection method according to claim 2 or 3, characterized in that: The desktop turbidity meter also includes a housing component, on which a touch display screen (15) is provided.

5. The water quality detection method according to claim 2 or 3, characterized in that: The light source module (25) comprises a light shield (251), a light source (254), a focusing lens assembly (241) and an aperture (243); the light source (254) is installed in the light shield (251); and the light source (254), the focusing lens assembly (241) and the aperture (243) are coaxially installed.

6. The water quality detection method according to claim 5, characterized in that: The desktop turbidity meter also includes a heat dissipation mechanism, which is used to dissipate heat from the light source module (25).

7. The water quality detection method according to claim 1, characterized in that: In the above steps, set , .

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