Water turbidity detection method and device

Abstract

The invention discloses a water turbidity detection method and device, and aims to solve the problems that a photoelectric sensor of an existing portable water turbidity meter is usually made of a semiconductor material, has photosensitivity, has dark current, is sensitive to external environment light and has large test errors. Respectively recording the output frequencies f0 and f1 of the high-precision QCM sensor when the light beam passes through the standard water body of the standard sample tube and the water body to be detected of the detected sample tube and then irradiates the high-precision QCM sensor, then converting the output frequencies f0 and f1 into corresponding illumination intensities I1 and I2, and finally obtaining a turbidity value S according to a turbidity value calculation formula. The sampled QCM sensor does not generate dark current and is not easily influenced by external environment light, so that the problem that the detection precision is influenced due to the fact that a photoelectric sensor based on a PN junction is sensitive to the external environment light is solved. The frequency (time) is a physical quantity with the highest test precision at present, and the method has higher precision.

Description

Technical Field

[0001] The present invention belongs to the technical field of water quality detection, and more specifically, relates to a method and device for detecting water turbidity. Background Art

[0002] Water turbidity detection (measurement) is an important indicator in the fields of water quality detection, water treatment, environmental protection, etc. It is related to people's life and health, and is also closely related to public health, environmental ecology, water resources management, social stability, etc. Therefore, it is of great significance to detect water turbidity.

[0003] The quartz resonant chip is connected to the crystal oscillation circuit as an inductor. The water quality turbidity detection method uses a water quality turbidity detection device, and the steps are as follows: I. The sensor probe is placed on the surface of the water body to be tested; II. The frequency value generated by the sensor probe in the water body to be tested is obtained from the frequency acquisition detection circuit; III. The water quality turbidity is judged. When the corresponding frequency of the measured water body is less than or equal to the corresponding frequency of qualified tap water, the turbidity of this water is qualified. The present invention can quickly and conveniently monitor water quality in real time to ensure water safety; it has stable performance, high sensitivity, and is not easily affected by the environment; it can be used for turbidity detection of water outlet from a tap water filter. This invention simply judges whether the water turbidity is qualified, and cannot accurately detect the turbidity of water quality.

[0004] The main methods for water turbidity detection (measurement) are:

[0005] Turbidimetry: Compare the water sample with the standard solution to measure the turbidity. This method is simple and intuitive, but is greatly affected by subjective factors.

[0006] Scattered light method: Use the turbidity meter to emit light, pass through the water sample and detect the scattered light intensity at 90 degrees. This method has high sensitivity and is suitable for measuring the turbidity of a variety of liquids.

[0007] Light transmittance measurement method: Turbidity is estimated by measuring the attenuation of light transmittance.

[0008] The transmittance measurement method is as follows: a beam of parallel light propagates in a transparent water body. If there are no suspended particles in the liquid, the light beam will not change direction when propagating in a straight line; if there are suspended particles in the water body, regardless of whether the particles are transparent or not, the light beam will change direction when encountering the particles, forming scattered light in all directions. The more particles there are, the higher the turbidity, and the greater the scattering effect on the light beam. Therefore, the turbidity information of the measured water body can be obtained by detecting the light intensity after passing through the standard water sampling tube and the measured water sampling tube. The turbidity of the measured water body is defined as S, the light intensity after passing through the standard water sampling tube is I1, the light intensity after passing through the measured water sampling tube is I2, the inherent parameter of the test instrument is k1, the optical path length of the sample cell is b, and the particles C in the sample have the following relationship:

[0009] S=-lg(I2 / I1)=k1bC (2)

[0010] Obviously, when light enters the water sample, the particles that make up the turbidity scatter the light, and the intensity of the scattered light is related to the turbidity of the water sample. In essence, the turbidity information can be obtained by calculating the light intensity after the light passes through the standard water sampling tube and the measured water sampling tube.

[0011] The existing portable turbidity meter using the transmittance measurement method generates emitted light through a photodiode or laser tube, and obtains turbidity information through a photoelectric sensor sensing the light intensity of the emitted light after passing through the measured water body. The photoelectric sensor of this portable turbidity meter is usually made of semiconductor materials, which is photosensitivity and has dark current. It is also sensitive to external ambient light and has large test errors. Summary of the invention

[0012] The purpose of the present invention is to overcome the deficiencies of the prior art and provide a method and device for detecting water turbidity to avoid the problem that the photoelectric sensor based on the PN junction is sensitive to the external ambient light and affects the detection accuracy.

[0013] To achieve the above-mentioned object of the invention, the water turbidity detection method of the present invention is characterized by comprising the following steps:

[0014] (1) First, use a standard sample tube to collect standard water, and use a sample tube to collect water to be tested. Then, place the standard sample tube and the sample tube to be tested in a sample tube storage bin, and close the sample tube storage bin to prevent external light from interfering with the detection.

[0015] (2) Use a high-precision QCM sensor as a sensor for sensing light intensity, use a QCM sensor driving circuit to drive the QCM sensor to oscillate and output a frequency signal, collect the output frequency of the high-precision QCM sensor without any light, record it as f0, irradiate the incident light beam generated by the light source to the standard sample tube, and then irradiate the light beam to the high-precision QCM sensor after passing through the standard water body of the standard sample tube, and record the output frequency of the high-precision QCM sensor, record it as f1, switch the incident light beam generated by the light source to irradiate the sample tube to be tested, and then irradiate the incident light beam to the high-precision QCM sensor after passing through the water body to be tested in the sample tube to be tested, and record the output frequency of the high-precision QCM sensor, record it as f2;

[0016] (3) Calculate the light intensity I1 of the incident light beam after it passes through the standard water in the standard sample tube:

[0017]

[0018] Among them, C Pf is the light intensity-frequency conversion coefficient of the QCM sensor;

[0019] Calculate the light intensity I2 after the incident light beam passes through the water body of the sample tube under test:

[0020]

[0021] (4) Calculate the turbidity value S of the measured water body:

[0022] S=-lg(I2 / I1) (4)

[0023] Based on the above water turbidity detection method, the present invention also constructs a water turbidity detection device, including:

[0024] a light source for generating an incident light beam;

[0025] Standard sample tube, used to store standard water;

[0026] The sample tube to be tested is used to store the water to be tested;

[0027] The sample tube storage bin is used to store standard sample tubes and sample tubes to be tested: the standard sample tubes and the sample tubes to be tested are placed on a rotating device with a roller in the sample tube storage bin, and the incident light beam generated by the light source is irradiated to the standard sample tube or switched to irradiate to the sample tube to be tested by means of rotation adjustment;

[0028] It is characterized by further comprising:

[0029] High-precision QCM sensor, used as a sensor to sense light intensity;

[0030] A QCM sensor driving circuit, used for driving the QCM sensor to oscillate and output a frequency signal;

[0031] The signal acquisition and processing circuit is used to acquire the output frequency signal of the QCM driving circuit. First, the output frequency of the high-precision QCM sensor without any light is acquired, which is recorded as f0. When the incident light beam passes through the standard water body of the standard sample tube and then irradiates the high-precision QCM sensor, the output frequency of the high-precision QCM sensor is recorded, which is recorded as f1. When the incident light beam passes through the water body to be tested in the sample tube and then irradiates the high-precision QCM sensor, the output frequency of the high-precision QCM sensor is recorded, which is recorded as f2. Then the turbidity value S of the water body to be tested is calculated:

[0032] S=-lg(I2 / I1)

[0033] in:

[0034]

[0035] C Pf is the light intensity-frequency conversion coefficient of the high-precision QCM sensor.

[0036] The object of the present invention is achieved in this way.

[0037] The water quality turbidity detection method and device of the present invention aim at the existing portable water quality turbidity meter, whose photoelectric sensor is usually made of semiconductor materials, has photosensitivity, has dark current, is relatively sensitive to external ambient light, and has large test errors. A high-precision QCM sensor is used as a sensor for sensing light intensity, and the output frequencies f0 and f1 of the high-precision QCM sensor are respectively recorded when the light beam passes through the standard water body of the standard sample tube and the water body to be tested in the tested sample tube and irradiates the high-precision QCM sensor, and then converted into corresponding light intensities I1 and I2, and finally the turbidity value S is obtained according to the turbidity value calculation formula.

[0038] Compared with the existing portable water turbidity meter, the present invention has the following technical advantages:

[0039] 1) The QCM sensor sampled by the present invention does not generate dark current and is not easily affected by ambient light, thereby avoiding the problem that the PN junction-based photoelectric sensor is sensitive to ambient light and affects the detection accuracy.

[0040] 2) The present invention directly converts the frequency information of the QCM sensor into light intensity, thereby obtaining the turbidity value of the measured water body. Frequency (time) is the physical quantity with the highest test accuracy at present. Therefore, the present invention has higher accuracy than the traditional portable water turbidity meter composed of semiconductor-based photoelectric sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of a specific implementation method of the water turbidity detection method of the present invention;

[0042] Figure 2 It is a structural schematic diagram of a specific implementation method of the water turbidity detection device of the present invention;

[0043] Figure 3 yes Figure 2 The three-dimensional assembly diagram of the water turbidity detection device shown. DETAILED DESCRIPTION

[0044] The specific implementation of the present invention is described below in conjunction with the accompanying drawings so that those skilled in the art can better understand the present invention. It should be noted that in the following description, when the detailed description of known functions and designs may dilute the main content of the present invention, these descriptions will be omitted here.

[0045] Figure 1 It is a flow chart of a specific implementation method of the water turbidity detection method of the present invention.

[0046] In this embodiment, if Figure 1As shown, the water turbidity detection method of the present invention comprises the following steps:

[0047] Step S1: Collect standard water and the water to be tested and place them in the sample tube storage bin

[0048] First, use the standard sample tube to collect standard water, and use the sample tube to collect the water to be tested. Then, place the standard sample tube and the sample tube to be tested in the sample tube storage bin, and close the sample tube storage bin to avoid interference with the detection by external light.

[0049] Step S2: construct a frequency measurement circuit based on a high-precision QCM sensor and collect the QCM sensor output frequencies f0, f1, and f2 without any light, when the incident light beam passes through the standard water body and the water body to be tested.

[0050] A high-precision QCM sensor is used as a sensor for sensing light intensity. A QCM sensor driving circuit is used to drive the QCM sensor to oscillate and output a frequency signal. The output frequency of the high-precision QCM sensor without any light is collected and recorded as f0. The frequency f0 is the inherent resonant frequency of the high-precision QCM sensor.

[0051] The incident light beam generated by the light source is irradiated to the standard sample tube. After passing through the standard water body of the standard sample tube, the light beam is irradiated to the high-precision QCM sensor. The output frequency of the high-precision QCM sensor is recorded and recorded as f1. The incident light beam generated by the light source is switched to irradiate the sample tube to be tested. After passing through the water body to be tested in the sample tube to be tested, the incident light beam is irradiated to the high-precision QCM sensor. The output frequency of the high-precision QCM sensor is recorded and recorded as f2.

[0052] Step S3: The QCM sensor output frequencies f0, f1, and f2 calculate the light intensity I1 of the incident light beam after the standard water body and the light intensity I2 of the measured water body

[0053] Calculate the illumination intensity I1 of the incident light beam after it passes through the standard water in the standard sample tube:

[0054]

[0055] Among them, C Pf is the light intensity-frequency conversion coefficient of the QCM sensor;

[0056] Calculate the light intensity I2 after the incident light beam passes through the water body of the sample tube under test:

[0057]

[0058] Step S4: Calculate the turbidity value S of the measured water body:

[0059] S=-lg(I2 / I1) (4)

[0060] Figure 2 , 3 They are respectively a structural schematic diagram and a three-dimensional assembly diagram of a specific implementation manner of the water turbidity detection device of the present invention.

[0061] In this embodiment, if Figure 2 , 3 As shown, the water quality turbidity detection device of the present invention includes: a light source 1, a standard sample tube 2, a sample tube to be tested 3, a sample tube storage bin 4, a high-precision QCM sensor 5, a QCM sensor driving circuit 6, and a signal acquisition and processing circuit 7.

[0062] The light source 1 generates an incident light beam, the standard sample tube 2 is placed in the standard water body, the sample tube to be tested 3 is placed in the water body to be tested, and the standard sample tube and the sample tube to be tested are placed in the sample tube storage bin 4: the standard sample tube 2 and the sample tube to be tested 3 are placed on a rotating device with a roller in the sample tube storage bin, and the incident light beam generated by the light source 1 is irradiated to the standard sample tube 2, or switched to irradiate the sample tube to be tested 3 through a rotation adjustment method. The high-precision QCM sensor 5 is used as a sensor to sense light intensity. The QCM sensor driving circuit 6 drives the QCM sensor 5 to oscillate and output a frequency signal. The signal acquisition and processing circuit 7 collects the frequency signal output by the QCM driving circuit. First, the output frequency of the high-precision QCM sensor 5 without any light is collected, which is recorded as f0. When the incident light beam passes through the standard water body of the standard sample tube 2 and irradiates the high-precision QCM sensor 5, the output frequency of the high-precision QCM sensor 5 is recorded, which is recorded as f1. When the incident light beam passes through the water body to be tested in the sample tube 3 and irradiates the high-precision QCM sensor 5, the output frequency of the high-precision QCM sensor 5 is recorded, which is recorded as f2. Then, the turbidity value S of the water body to be tested is calculated:

[0063] S=-lg(I2 / I1)

[0064] in:

[0065]

[0066] C Pf is the light intensity-frequency conversion coefficient of the high-precision QCM sensor 5.

[0067] In this embodiment, if Figure 2 , 3 As shown, the QCM sensor driving circuit 6 and the signal acquisition and processing circuit 7 are on a circuit board.

[0068] In addition, the water quality turbidity detection device of the present invention is a portable water turbidity meter, which also includes a battery 9, a power switch 10, a light source switch 11, a light source control circuit 12, a data display module 13, a data output interface 14, and a charging interface 15. The battery 9 and the power switch 10 are located at the bottom, and the light source switch 11 is located at the top. The battery 9 supplies power to the light source control circuit 11, the sensor driving circuit 6, the signal acquisition and processing circuit 7, and the data display module 13 through the power switch 10. Among them, the light source control circuit 12 is used to drive the light source 1, and the light source switch 11 is connected to it, which is used to turn on or off the light source 1. When it is turned off, the output frequency f0 of the high-precision QCM sensor 5 is collected. When it is turned on, the frequencies f1 and f2 of the incident light beam after passing through the standard water body of the standard sample tube 2 and the water body to be tested in the sample tube 3 to irradiate the high-precision QCM sensor 5 are collected respectively.

[0069] The data display module 13 is used to display the turbidity value of the measured water body in real time, the data output interface 14 is used to communicate with other devices, the data display module 13 and the data output interface 14 are both connected to the signal acquisition and processing circuit 7, and the charging interface 15 is used to charge the battery 9.

[0070] In this embodiment, if Figure 2 , 3 As shown, the water quality turbidity detection device of the present invention is a cylindrical tube, the top and bottom surfaces of the cylindrical tube are sealed, the light source switch 11 is located on the top surface, the light source control circuit 12 is located inside the top surface of the cylindrical tube, below it is the light source 1, below the light source 1 is the sample tube storage bin 4, below the sample tube storage bin 4 is the high-precision QCM sensor 5, and the wall of the cylindrical tube is opened below the sample tube storage bin 4 for installing the data display module 13. In this embodiment, the circuit board where the QCM sensor driving circuit 6 and the signal acquisition and processing circuit 7 are located is located below the sample tube storage bin 4 in the cylindrical tube.

[0071] The technicians in this field can design each module according to the specific situation, which will not be described in detail here.

[0072] Although the above describes the illustrative specific embodiments of the present invention to facilitate those skilled in the art to understand the present invention, it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations using the concept of the present invention are protected.

Claims

1. A method for detecting water turbidity, It is characterized in that The following steps are involved: (1) First, use a standard sample tube to collect standard water, and use a sample tube to collect water to be tested. Then, place the standard sample tube and the sample tube to be tested in a sample tube storage bin, and close the sample tube storage bin to prevent external light from interfering with the detection. (2) Use a high-precision QCM sensor as a sensor for sensing light intensity, use a QCM sensor driving circuit to drive the QCM sensor to oscillate and output a frequency signal, and collect the initial output frequency of the high-precision QCM sensor under normal test environment illumination, recorded as f 0 , the incident light beam generated by the light source is irradiated to the standard sample tube, and the light beam passes through the standard water body of the standard sample tube and then irradiates to the high-precision QCM sensor, and the output frequency of the high-precision QCM sensor is recorded, which is recorded as f 1 , the incident light beam generated by the light source is switched to irradiate the sample tube under test, and the incident light beam passes through the water body to be tested in the sample tube under test and then irradiates the high-precision QCM sensor, and the output frequency of the high-precision QCM sensor is recorded, which is recorded as f 2 ; (3) Calculate the light intensity I of the incident light beam after it passes through the standard water in the standard sample tube. 1 : Among them, C Pf is the light intensity-frequency conversion coefficient of the QCM sensor; Calculate the light intensity I after the incident light beam passes through the water body of the sample tube to be tested 2 : (4) Calculate the turbidity value S of the measured water body: S=-lg(I 2 / AND 1 ).

2. A water turbidity detection device, include: a light source for generating an incident light beam; Standard sample tube, used to store standard water; The sample tube to be tested is used to store the water to be tested; The sample tube storage bin is used to store standard sample tubes and sample tubes to be tested: the standard sample tubes and the sample tubes to be tested are placed on a rotating device with a roller in the sample tube storage bin, and the incident light beam generated by the light source is irradiated to the standard sample tube or switched to irradiate to the sample tube to be tested by means of rotation adjustment; It is characterized by further comprising: High-precision QCM sensor, used as a sensor to sense light intensity; A QCM sensor driving circuit, used for driving the QCM sensor to oscillate and output a frequency signal; The signal acquisition and processing circuit is used to collect the output frequency signal of the QCM driving circuit. First, the initial output frequency of the high-precision QCM sensor under normal test environment illumination is collected, which is recorded as f 0 When the incident light beam passes through the standard water in the standard sample tube and then irradiates the high-precision QCM sensor, the output frequency of the high-precision QCM sensor is recorded and recorded as f 1 When the incident light beam passes through the water in the sample tube and irradiates the high-precision QCM sensor, the output frequency of the high-precision QCM sensor is recorded and recorded as f 2 , and then calculate the turbidity value S of the measured water body: S=-lg(I 2 / AND 1 ) in: C Pf is the light intensity-frequency conversion coefficient of the high-precision QCM sensor.

3. The water turbidity detection device according to claim 2, It is characterized in that The QCM sensor driving circuit and the signal acquisition and processing circuit are on a circuit board; The water quality turbidity detection device is a portable water turbidity meter, which also includes a battery, a power switch, a light source switch, a light source control circuit, a data display module, a data output interface, and a charging interface. The battery and the power switch are located at the bottom, and the light source switch is located at the top. The battery supplies power to the light source control circuit, the sensor drive circuit, the signal acquisition and processing circuit, and the data display module through the power switch. The light source control circuit is used to drive the light source, and a light source switch is connected to it to turn on or off the light source. When it is turned off, the output frequency f of the high-precision QCM sensor is collected. 0 When it is turned on, the frequency f of the incident light beam passing through the standard water in the standard sample tube and the water to be tested in the tested sample tube and then irradiating to the high-precision QCM sensor is collected. 1 、f 2 ; The data display module is used to display the turbidity value of the measured water body in real time, the data output interface is used to communicate with other devices, the data display module and the data output interface are connected to the signal acquisition and processing circuit, and the charging interface is used to charge the battery.

4. The water turbidity detection device according to claim 3, It is characterized in that The water quality turbidity detection device is a cylindrical tube. The top and bottom surfaces of the cylindrical tube are sealed. The light source switch is located on the top surface, and the light source control circuit is located inside the top surface of the cylindrical tube. Below it is the light source, and below the light source is the sample tube storage bin. Below the sample tube storage bin is a high-precision QCM sensor. The wall of the cylindrical tube has a window below the sample tube storage bin for installing a data display module. The circuit board where the QCM sensor drive circuit and the signal acquisition and processing circuit are located is located below the sample tube storage bin in the cylindrical tube.

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