Table type turbidity meter and water quality detection method

Abstract

The invention relates to the technical field of turbidity meters, and discloses a table type turbidity meter and a water quality detection method.The table type turbidity meter comprises a light path module, the light path module comprises a light source module, a sample detection position and a sensor module, the sensor module comprises a transmission light sensor and a scattered light sensor, and the optical axis of the light source module penetrates through the transmission light sensor; the light path module is internally provided with at least two groups of scattered light sensors, the scattered light sensors are respectively a first scattered light sensor and a second scattered light sensor, and during detection, the scattered light sensors receive scattered light at different heights, in the scheme, the at least two groups of scattered light sensors are arranged in the light path module, and the two groups of scattered light sensors are distributed at different heights; according to the technical scheme, scattered light signals of different heights can be received, and the reason, such as sedimentation or disturbance, for causing unstable turbidity is judged according to the scattered light signals of different heights, so that a user can timely eliminate the problems existing in a water sample, and a more reliable and accurate detection result is obtained.

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 desktop turbidity meter of the present invention is mainly characterized in that at least two sensors are arranged up and down on the side of a colorimetric bottle for testing a water sample, and the measured values ​​of multiple sensors are used to evaluate the stability of the water sample, so as to judge whether the water sample has disturbance and sedimentation problems, and timely eliminate the auxiliary problems, thereby obtaining more accurate detection results. The desktop turbidity meter specifically includes an optical path module, 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 tested, 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, and the scattered light sensor is arranged in at least two groups, 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 high and one low. During detection, each of the scattered light sensors receives scattered light at different heights.

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

[0009] Furthermore, the first scattered light sensor and the second scattered light sensor are respectively arranged at a height higher than the optical axis and a height lower than the optical axis, and are preferably symmetrically arranged at height positions on both sides of the optical axis with the optical axis as the center.

[0010] Furthermore, the scattered light sensor also 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, respectively arranged at two sides of the water sample to be tested.

[0011] Optionally, when the accuracy of the detection result needs to be further improved, the number of scattered light sensors may be increased to four or more.

[0012] Furthermore, the transmission light sensor is installed at an angle to reflect the light reaching the transmission light sensor to the side wall, thereby preventing the reflected light from returning along the original path and reducing stray light. It is preferably installed at an angle of 45°.

[0013] Furthermore, the desktop turbidity meter also includes a shell assembly, on which a touch screen is provided. The touch screen can be used to display information such as detection parameters and steps and to control detection operations, thereby providing a better operating experience.

[0014] Furthermore, the light source module includes a light shield, a light source, a focusing lens assembly and an aperture, the light source is installed in the light shield, the light source, the focusing lens assembly and the aperture are coaxially installed, the aperture is a light shield with a circular hole in the center, the aperture has at least one light shield, and the focusing lens assembly is provided with at least one lens.

[0015] Furthermore, the desktop turbidity meter also includes a heat dissipation mechanism, which is used to dissipate heat from the light source module. The heat dissipation mechanism can be configured as a heat dissipation fan, heat dissipation fins, heat pipe heat dissipation and other structures.

[0016] A water quality detection method, based on the above-mentioned desktop turbidity meter, comprises the following steps:

[0017] Steps to receive signal:

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

[0019] Turn on the light source module, the light beam passes through the water sample, and the transmitted light signal is received by the transmitted light sensor set 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 ;

[0020] Stability assessment steps:

[0021] when When , the signal is determined to be stable, and the turbidity value calculation step is executed;

[0022] when When the water sample is determined to have sedimentation problems, shake it evenly and measure it again;

[0023] 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.

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

[0025] Turbidity value calculation steps:

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

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

[0028] Beneficial effects of the present invention: In this solution, by setting a scattered light sensor in the optical path module, and setting at least two groups, and the two groups of scattered light sensors are distributed at different heights, it is possible to receive scattered light signals at different heights, and then judge the cause of turbidity instability, such as sedimentation or disturbance, according to the scattered light signals at different heights, so that the user can promptly eliminate the problems existing in the water sample and obtain more reliable and accurate detection results.

[0029] In addition, when calculating turbidity, the average measurement of multiple 90° scattered signals is conducive to data stability, reducing the impact of colorimetric bottle differences on turbidity and reducing the impact of water sample fluctuations on turbidity. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

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

[0032] Figure 1 It is a schematic diagram of the overall structure of a desktop turbidity meter;

[0033] Figure 2 This is a schematic diagram of the overall structure of the desktop turbidity meter after opening the cover;

[0034] Figure 3 This is the rear view of the benchtop turbidity meter;

[0035] Figure 4 Schematic diagram of the explosion of the benchtop turbidity meter;

[0036] Figure 5 Explosion diagram of the optical path module;

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

[0038] Figure 7 is a schematic diagram of the optical path;

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

[0040] Fig. 9 is a top view of the optical path module in Example 2;

[0041] Fig.10 Schematic diagram of the relationship between sedimentation threshold, disturbance threshold and water sample state. DETAILED DESCRIPTION

[0042] Combine the following Figure 1-Figure 10 The present invention is described in detail.

[0043] Embodiment 1:

[0044] A desktop turbidity meter of the present invention comprises a housing component and an optical path module 2.

[0045] like Figure 1-Figure 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 shell 1 is provided with a front acrylic plate 11, a front groove 12, a measuring groove shading cover 13, an upper acrylic plate 14, a touch display screen 15, an upper groove 16, an instrument switch 17, a switch mounting groove 18 and a display screen mounting 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 mounting groove 18; the touch display screen 15 is installed in the display screen mounting groove 19.

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

[0048] like Figure 5-Figure 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 column 26 .

[0049] A colorimetric bottle socket 231 is provided on the top of the optical path cover 23. During measurement, the colorimetric bottle 22 is inserted from the colorimetric bottle socket into the sample detection position 27. A light inlet 232 is provided at one end of the optical path cover 23. The light source module 25 emits light that is incident from the light inlet 232 to the optical measurement system installed on the base plate 24. The positioning column 26 is used to assist in the positioning and installation of the optical path cover 23 and the base plate 24.

[0050] The light source module 25 is provided with a light shield 251, a light source fixing seat 253 and a light source 254. The bottom of the light shield 251 is provided with a heat dissipation hole 252. The light source 254 is installed on the light source fixing seat 253 and then installed in the light shield 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 base 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 and is mounted inside the lens mounting seat 242 . The lens mounting seat 242 is mounted on the bottom plate 24 .

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

[0054] The 90° scattered light sensor fixing base 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 base 244 is installed on the base plate 24 .

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

[0056] The light source 254, the light inlet hole 232, the focusing lens assembly 241, and the aperture 243 are coaxially installed, with their centers on a horizontal line. The center of the 180° transmission light sensor fixing seat 247 is aligned with the above-mentioned light path, and the installation angle is 45°, so that the light reaching the transmission light sensor is reflected to the side wall to avoid the reflected light from returning along the original path, thereby reducing stray light.

[0057] The 90° scattered light sensor fixing seat 244 is installed on the side of the cuvette 22, forming an angle of 90° with the above-mentioned optical axis, and receives the 90° scattered light signal.

[0058] During detection, ideally, if the water sample is stable and meets the requirements for turbidity measurement, the distance traveled by the light signal reaching the two scattered light sensors is the same, and the measurement values ​​of the two scattered light sensors are similar; when the suspended particles in the water sample are disturbed, the signal sizes of the two sensors will be different, and the degree of disturbance of the water sample can be obtained by evaluating the difference between the signals of the two scattered light sensors; when the suspended particles in the water sample are precipitated, the signal of the sensor below will be larger than the signal of the sensor above, and the degree of precipitation of the water sample can be evaluated by evaluating the signal ratio of the upper and lower sensors; different measures should be taken for water samples with disturbance and precipitation. 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 that the problems with the water sample can be eliminated in time and more reliable and accurate detection results can be obtained.

[0059] Embodiment 2:

[0060] On the basis of Example 1, Figure 8A second 90° scattered light sensor fixing seat 245 is arranged in a mirror image opposite to the 90° scattered light sensor fixing seat 244, and a third light-transmitting window 2451 and a fourth light-transmitting window 2452 are arranged on the second 90° scattered light sensor fixing seat 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, namely, the signal of the first scattered light sensor 2443 , the signal of the second scattered light sensor 2444 , respectively, are the signals of the three scattered light sensors 2453 , the signal of the fourth scattered light sensor 2454 .

[0062] By judging the four-way 90° scattered signals, the stability assessment will be more accurate; by averaging the four-way 90° scattered signals, the turbidity data will also be more accurate.

[0063] A water quality detection method embodiment 1, based on the desktop turbidity meter in any of the above embodiments, comprises the following steps:

[0064] Step 1: Receive the signal. 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 cuvette 22. During the transmission process, the turbidity and suspended particles of the water sample in the cuvette 22 will be absorbed and scattered. The transmitted light sensor 246 arranged behind the cuvette 22 receives the 180° transmitted light signal. The first scattered light sensor 2443 disposed on the side of the cuvette 22 receives the scattered light at the upper center of the cuvette 22. The second scattered light sensor 2444 disposed on the side of the cuvette 22 receives the scattered light at the lower center of the cuvette 22. ;

[0065] According to the turbidity scattering theory, ;

[0066] ;

[0067] ;

[0068] In the formula, is the incident light intensity, K is the proportional constant, T is the turbidity, is the optical path of the projected light, usually the diameter of the cuvette; is the absorption related to the scattering function coefficient; It is the number of particles contained in the water sample above the center of the colorimetric bottle; It is the number of particles contained in the water sample below the center of the colorimetric bottle; is the optical path to the first scattered light sensor above the center of the cuvette, is the optical path to the second scattered light sensor below the center of the cuvette. Since the first scattered light sensor and the second scattered light sensor are arranged at symmetrical positions above and below the center of the cuvette, the optical paths are the same, that is, ;

[0069] Therefore, the particles above and below the bottle , The difference will cause and are different.

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

[0071] When the turbidity distribution is uneven, ,therefore ;

[0072] Step 2: Stability assessment. Suspended particles in actual water samples inevitably experience disturbance and sedimentation. Different measures need to be taken for turbidity measurement errors caused by different reasons. The patented method can determine the cause of the error. Specifically, the signal ratio of the first scattered light sensor 2443 and the second scattered light sensor 2444 is used to determine stability:

[0073] when When , the signal is considered stable, the turbidity particles are evenly distributed, and the turbidity data is true and reliable;

[0074] when When the water sample is settling, it is necessary to further determine whether it is caused by the disturbance of the water sample or the sedimentation. When the water sample is settling, the particles in the lower part of the colorimetric bottle are more than those in the upper part, that is, , determine whether it is caused by sedimentation, that is, continue to determine if , it is considered that there is settlement; usually ,therefore:

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

[0076] when ,and When the water sample is disturbed, it is considered that the water sample is disturbed and needs to be left to stand for a period of time before being measured again;

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

[0078] The disturbance threshold and settlement threshold are set as follows: Fig.10 As shown:

[0079] Set when , that is, when the number of particles below the center of the colorimetric bottle is about twice that of the particles below the center, that is, hour, , at this time, it is considered that there is sedimentation, and the water sample needs to be shaken before measurement;

[0080] When the water sample is shaken at time t1, the particles in the upper and lower parts of the colorimetric bottle are mixed and exchanged with each other, and the particles float in the whole bottle, forming a disturbance signal. When the particles float in the whole bottle, the particles in the upper and lower parts of the colorimetric bottle are almost the same, that is, and The difference is not big, but the drift of particles will cause signal disturbance, which will gradually stabilize over time, as shown in the figure from t1 to t2; The absolute value is taken here because the particles are floating, and there may be In the case of , it is more convenient to calculate by taking the absolute value. However, since the particles above and below are not much different, .

[0081] set up , that is, particles above and below the center of the colorimetric bottle ( ) is within 95%, it is considered stable. As shown in the figure, when it reaches time t2, At this time, the signal is stable, the water sample in the colorimetric bottle has little disturbance and no sedimentation, which is suitable for turbidity measurement.

[0082] A water quality detection method embodiment 2: also includes the following steps: when it is determined that there is a problem with the water sample, the user can be prompted by displaying it on the screen or emitting sound and light reminders.

[0083] Preferably, a shaking mechanism, such as a crank rocker, a cam or the like, may be provided at the sample detection position 27, which can shake the colorimetric bottle 22. When it is determined that sedimentation occurs, the shaking mechanism receives a shaking instruction from the control module to shake the colorimetric bottle 22. The shaking time and the standing time are directly proportional to 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 their purpose is to enable people familiar with the technology in this field to understand the content of the present invention and implement it, and they cannot 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 included in the protection scope of the present invention.

Claims

1. A desktop turbidity meter, characterized in that: The invention comprises an optical path module (2), wherein the optical path module (2) comprises a light source module (25), a sample detection position (27) and a sensor module. The sample detection position (27) is used to place a water sample to be detected. The sensor module comprises a transmitted light sensor (246) and a scattered light sensor. The optical axis of the light source module (25) passes through the transmitted light sensor (246). At least two groups of scattered light sensors are 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) are provided on the side of the optical axis and are arranged in sequence in the height direction. During detection, each of the scattered light sensors receives scattered light at different heights.

2. The desktop turbidity meter according to claim 1, characterized in that: The scattered light sensor is arranged at 90° to the optical axis.

3. The desktop turbidity meter according to claim 1 or 2, characterized in that: The first scattered light sensor (2443) and the second scattered light sensor (2444) are respectively arranged at a height higher than the optical axis and a height lower than the optical axis.

4. The desktop turbidity meter according to claim 3, 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).

5. The desktop turbidity meter according to claim 3, 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.

6. The desktop turbidity meter according to claim 4 or 5, characterized in that: The desktop turbidity meter also includes a housing component, on which a touch display screen (15) is provided.

7. The desktop turbidity meter according to claim 4 or 5, 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.

8. The desktop turbidity meter according to claim 7, 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).

9. A method for detecting water quality, based on the desktop turbidity meter according to any one of claims 1 to 8, comprising 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 determined to have sedimentation problems, shake it evenly and measure it again; 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.

10. The water quality detection method according to claim 9, characterized in that: In the above steps, set , .

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