In-situ algae detector with turbidity correction function

Abstract

The present invention provides an in-situ algae detector with turbidity correction, the in-situ algae detector comprises a container, a detection cavity and a mounting cavity are formed in the container, the detection cavity provides a detection environment for water detection, the detection cavity and the mounting cavity are not communicated with each other, the container is provided with a water inlet for external water to enter the detection cavity, and the water inlet is communicated with the mounting cavity. A light source is arranged in the detection cavity, a water body component detection channel and a turbidity detection channel are arranged at one end, close to the detection cavity, of the mounting cavity, during detection, light in the detection cavity can enter the water body component detection channel and the turbidity detection channel, and a detection unit is mounted in the mounting cavity; the detection unit is used for detecting components and turbidity of a water body to be detected through the water body component and turbidity detection channel and correcting detection signals of other water quality components according to collected turbidity information; according to the detector, the water body component detection channel and the turbidity detection channel are arranged at the same time, turbidity information is collected in real time in the detection process, detection signals of water quality components can be corrected, the influence of turbidity on fluorescence signals is effectively eliminated, and therefore the accuracy of detection data is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of water body detection, and in particular to an in-situ algae detector with turbidity correction. Background Art

[0002] With the aggravation of natural water pollution, the outbreak of algae bloom has a serious impact on people's lives. The quality of natural water is very important. The detection of algae such as cyanobacteria and soluble organic matter is of great significance for water quality monitoring and water pollution early warning. Since phycocyanin, chlorophyll and CDOM in cyanobacteria and green algae have corresponding fluorescence excitation bands, the fluorescence method is used to excite the fluorescence of each component. By detecting the intensity of fluorescence, the concentration of each component in the water can be determined.

[0003] In domestic patents, CN112683860A, CN206074399U, CN102023603A, etc. have disclosed many related similar algae detection products, which extract the water to be tested into a fixed detection chamber for composition and concentration analysis through sampling detection. The above equipment includes design solutions for use scenarios such as in-situ detection and pumping detection. Patent CN102023603A introduces an automatic lake algae monitoring system, which consists of a sampling device, algae observation equipment, an automatic drainage device, a control module and a communication module. It can automatically collect water samples, detect algae concentration, and transmit observation data over long distances.

[0004] In the actual detection of natural water bodies, the influence of sediment on the fluorescence signal cannot be ignored, which mainly includes shielding effect and fluorescence effect. Most of the existing detection instruments are detection probes and sensors. In practical applications, when the light source shines on the water in front of the detector, the influence of turbidity on the detection signal is not taken into account. The shielding effect makes the signal value smaller, and the fluorescence effect makes the signal value larger, and the detection window is easily affected by stray light near the water surface. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem that the influence of turbidity on the detection signal is not considered in the prior art.

[0006] In order to solve the above technical problems, the present invention provides an in-situ algae detector with turbidity correction, which includes: a container, a detection cavity and an installation cavity are formed in the container, the detection cavity provides a detection environment for water body detection, the detection cavity and the installation cavity are not connected to each other, a water inlet for external water to enter the detection cavity is opened on the container, a light source is arranged in the detection cavity, a water body component detection channel and a turbidity detection channel are arranged at one end of the installation cavity close to the detection cavity, during detection, the light in the detection cavity can enter the water body component detection channel and the turbidity detection channel, a detection unit is installed in the installation cavity, the detection unit detects the composition and turbidity of the water body to be detected through the water body component and turbidity detection channels, and corrects the detection signals of other water quality components according to the collected turbidity information.

[0007] Furthermore, a mounting plate is provided at one end of the mounting cavity close to the detection cavity, and a water component detection channel and a turbidity detection channel are both provided on the mounting plate. A window piece is provided between the mounting plate and the detection cavity, and the window piece is sealed and connected to the container. Light in the detection cavity can pass through the window piece into the water component and turbidity detection channels.

[0008] Furthermore, there are three water component detection channels, and the three water component detection channels detect phycocyanin, chlorophyll, and CDOM in the water in a one-to-one correspondence.

[0009] Furthermore, three water component detection channels and a turbidity detection channel are evenly arranged in a circle on the mounting plate.

[0010] Furthermore, it also includes a cleaning mechanism arranged in the container, and the cleaning mechanism is used for cleaning the window sheet.

[0011] Furthermore, the cleaning mechanism includes a driving motor arranged in the installation cavity and a cleaning brush located in the detection cavity for cleaning the window sheet, and the output end of the driving motor passes through the window sheet and is connected to the cleaning brush.

[0012] Furthermore, a first opening leading to the detection cavity is opened at the bottom of the container, and a filter covering the first opening is arranged at the bottom of the container.

[0013] Furthermore, a second opening leading to the detection cavity is formed on the side wall of the container, a light shield covering the second opening is arranged on the side wall of the container, a third opening is formed on the light shield, and the second opening and the third opening are arranged alternately.

[0014] Furthermore, a data acquisition circuit is arranged in the installation cavity, and also includes a bandpass filter and a photodetector. The bandpass filter and the photodetector are arranged in sequence in the water component detection channel and the turbidity detection channel in the direction away from the detection cavity.

[0015] Furthermore, the irradiation direction of the light source is perpendicular to the directions of the water component detection channel and the turbidity detection channel.

[0016] It can be seen from the above technical scheme that the beneficial effects of the present invention are as follows: the detector can correct the detection signals of water quality components by simultaneously setting up a water component detection channel and a turbidity detection channel, and collecting turbidity information in real time during the detection process, thereby effectively eliminating the influence of turbidity on the fluorescence signal, thereby greatly improving the accuracy of the detection data. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the in-situ algae detector with turbidity correction provided in the present application.

[0018] Figure 2 is a schematic diagram of the mounting plate provided in this application.

[0019] Figure 3 It is a schematic diagram of the transmission of the incident fluorescence signal provided in this application.

[0020] The description of the accompanying drawings is as follows: 1. container; 11. first cylinder; 111. first opening; 112. light source; 113. second opening; 114. light shield; 115. filter; 116. polytetrafluoroethylene inner shell; 12. second cylinder; 121. data acquisition circuit; 122. mounting plate; 123. window piece; 124. bandpass filter; 125. photodetector; 126. motor; 127. brush; 128. lifting ring. DETAILED DESCRIPTION

[0021] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various changes in different embodiments without departing from the scope of the present invention, and the descriptions and illustrations therein are essentially used for illustration purposes rather than for limiting the present invention.

[0022] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0023] In order to further illustrate the principle and structure of the present invention, preferred embodiments of the present invention are now described in detail with reference to the accompanying drawings.

[0024] See also Figure 1-3 , an in-situ algae detector with turbidity correction provided in this embodiment includes a container 1, a mounting cavity for mounting a detection unit and a detection cavity for providing a detection environment are arranged in the container 1, because the detection unit has electronic components, it needs to be isolated from water, the detection cavity and the mounting cavity are not connected to each other, a water inlet for external water to enter the detection cavity is opened on the container 1, a light source 112 is arranged in the detection cavity, a water component detection channel and a turbidity detection channel are arranged at one end of the mounting cavity close to the detection cavity, the detection unit is connected with the water component detection channel and the turbidity detection channel, when detecting, the water to be detected enters the detection cavity through the water inlet, the light source 112 irradiates the water in the detection cavity, excites the pigments and organic matter in the algae to emit fluorescence, the excited fluorescence signal enters the water component detection channel, the light signal scattered by the suspended matter in the water enters the turbidity detection channel, the detection unit calculates the water component and turbidity value according to the fluorescence signal and the light signal of the suspended matter, and corrects the detection signals of other water quality components according to the collected turbidity value to improve the accuracy of the data.

[0025] A mounting plate 122 is provided at one end of the mounting cavity close to the detection cavity. The water component detection channel and the turbidity detection channel are both provided on the mounting plate 122. In order to enable the fluorescent signal generated in the detection cavity and the optical signal of the suspended matter to enter the detection channel, a window piece 123 is provided between the mounting plate 122 and the detection cavity. The window piece 123 is made of a transparent material. The window piece 123 is sealed and connected to the container 1 to prevent water from entering the mounting cavity.

[0026] Furthermore, the number of the above-mentioned water component detection channels is three, and the three water component detection channels correspond to each other to detect phycocyanin, chlorophyll, and CDOM in the water. By setting up three detection channels, phycocyanin, chlorophyll, and CDOM in the water can be detected simultaneously without switching the detection probes in sequence, thereby greatly improving the detection efficiency; and each water component has different fluorescence excitation and emission bands. By setting up multiple independent detection channels for detecting water components, it can be ensured that only the fluorescence signal of the corresponding component is captured, effectively avoiding signal interference between different components, which helps to improve the measurement accuracy.

[0027] It should be noted that the detection channels for detecting water components in the present invention are not limited to three, and four, five, six or more detection channels may be provided according to the circumstances.

[0028] The above-mentioned detection unit includes a bandpass filter 124, a photodetector 125, a data acquisition circuit 121 and a host computer. A bandpass filter 124 and a photodetector 125 are provided in each water component detection channel and turbidity detection channel. The bandpass filter 124 and the photodetector 125 are arranged in sequence in the water component detection channel and the turbidity detection channel in the direction away from the detection cavity. The band of the bandpass filter 124 is selected to avoid the peak band of the fluorescence of each component, thereby avoiding the influence of the overlapping of the fluorescence signals of each component on the detection accuracy. The band of the bandpass filter 124 can be replaced and set as needed; the data acquisition circuit 121 is arranged in the installation cavity and is electrically connected to the photodetector 125. The host computer can be selected to be arranged in the installation cavity or outside the container 1. In order to reduce the volume of the detector, this application Preferably, the host computer is arranged outside the container 1; a bus connector is arranged on the container 1, and the host computer is electrically connected to the data acquisition circuit 121 through the bus connector; a bandpass filter 124 corresponding to the detection component is arranged in the water component detection channel to ensure that only the fluorescence signal of the corresponding component is captured; the photodetector 125 converts the received fluorescence signal and the optical signal of the suspended matter into a photocurrent, and the data acquisition circuit 121 receives the photocurrent, and the photocurrent is converted into a packet in the data acquisition circuit 121 and sent to the host computer via the bus, and by changing the value of the charge and discharge capacitor, detection at high, medium and low concentrations can be achieved; the host computer processes the digital signal after the digital-to-analog conversion to obtain accurate measurement results of the water component and turbidity, and corrects the detection signals of other water quality components according to the collected turbidity value.

[0029] The present invention provides a method for correcting the effect of turbidity

[0030] The influence of turbidity on chlorophyll measurement is reflected in the fact that when light enters the water body, the suspended matter in the water will block or disperse the light, causing the light intensity to change. Therefore, the influence of turbidity on the measurement of pigment fluorescence signals mainly exists in two aspects: fluorescence effect and shielding effect.

[0031] Taking offshore sediment as an example, the fluorescence effect of turbidity will increase the fluorescence value measured by the fluorometer, while the shielding effect will decrease the fluorescence value. Therefore, the main idea of ​​data correction is to deduct the fluorescence value generated by the fluorescence effect from the actual measured fluorescence value, and add the fluorescence value reduced by the shielding effect. The fluorescence effect of turbidity is corrected by linear regression method. Since the intensity of the shielding effect is related to the mass concentration of the algae solution, it is difficult to directly use the linear regression method for correction, but the rate of change of the pigment fluorescence difference is not related to the mass concentration of the algae solution, and has an excellent linear relationship with turbidity. Therefore, the rate of change of the pigment fluorescence difference can be used to correct the shielding effect. The fitting formula for sediment turbidity and pigment signal value can be expressed as follows:

[0032] Flu A =A×T u +A0 (15)

[0033] Where: is the pigment signal value generated by the fluorescence effect, in mV; is the turbidity value, in NTU; and is the fluorescence effect correction coefficient, so the correction formula for the fluorescence effect can be obtained:

[0034] ΔFlu=Flu-Flu A =Flu-A×T u -A0 (16)

[0035] The pigment fluorescence value corrected by formula (16) at each turbidity point is subtracted from the initial pigment fluorescence value (pigment signal value measured when the turbidity is 0) to obtain the pigment fluorescence difference at each turbidity point, which is then divided by the initial pigment fluorescence value. The change rate of the pigment fluorescence difference at each turbidity point is shown in the following formula:

[0036] ΔFlu B =(ΔFlu-Flu) / Flu (17)

[0037] Fit the corresponding turbidity value at each turbidity to obtain the fitting formula:

[0038] ΔFlu B =B×T u +B0 (18)

[0039] Where: and are the shielding effect correction coefficients. Substituting formula (16) and formula (18) into formula (17), the relationship between the initial chlorophyll fluorometer fluorescence value and turbidity can be obtained:

[0040] Flu=(Flu-A×T u A0) / (1+B×T u +B0) (19)

[0041] Where: is the actual pigment fluorescence value in the water body, that is, the required correction value based on turbidity. Therefore, formula (19) is the correction formula for pigment fluorescence with respect to sediment turbidity.

[0042] Furthermore, four detection channels (three water component detection channels and one turbidity detection channel) are evenly arranged in a circle on the mounting plate 122, and combined with the control circuits tightly arranged inside the instrument, the algae detector can achieve multi-band simultaneous detection of the internal area of ​​the same detection zone cavity using only a smaller volume.

[0043] Furthermore, it also includes a cleaning mechanism, which is used to clean the window piece 123, and the cleaning mechanism is arranged in the container 1; specifically, the cleaning mechanism includes a driving motor 126 arranged in the installation cavity and a cleaning brush located in the detection cavity for cleaning the window piece 123, and the output end of the driving motor 126 passes through the window piece 123 and is connected to the cleaning brush; the driving motor 126 can drive the brush 127 to rotate to clean the window piece 123; because the detection instrument is placed underwater for a long time, when the signal is too large or too small, it may be caused by the excessive concentration of algae in the water body or the algae blocking the detection channel, at this time, the brush 127 is started to clean the window glass.

[0044] Furthermore, a first opening 111 leading to the detection cavity is opened at the bottom of the container 1 , and external water enters the detection cavity through the first opening 111 . When the detector is lifted out of the water, the water is discharged from the first opening 111 .

[0045] Furthermore, the side wall of the container 1 is also provided with a second opening leading to the detection cavity (not shown in the figure). There are three second openings, which are evenly distributed on the side wall of the container 1 at intervals of 120 degrees. When the detector in the water is pulled up and down, the first opening 111 and the second opening can ensure that the water in the detection cavity can continue to circulate and be renewed, thereby improving the timeliness and accuracy of the detection.

[0046] Furthermore, a light shield 114 covering the second opening is provided on the side wall of the container 1, and three third openings 113 corresponding to the second openings are provided on the light shield 114. The second openings and the third openings 113 are staggered to form a maze-type light shield 114. The design of the light shield 114 reduces the influence of stray light near the water surface on the inside of the detection cavity while ensuring the inlet and outlet of water.

[0047] Furthermore, the detection cavity also includes a polytetrafluoroethylene inner shell 116. The light source 112 irradiates the polytetrafluoroethylene inner shell 116, which can make the light more evenly distributed in the cavity through its homogenization effect, thereby improving the accuracy and reliability of algae detection.

[0048] Furthermore, the light source 112 is arranged on the side wall of the detection cavity so that the irradiation direction of the light source 112 is perpendicular to the direction of the water component detection channel and the turbidity detection channel, thereby achieving a 90-degree angle between the light source 112 and the detection channel. This arrangement helps to reduce the interference caused by the light source 112 directly irradiating the detector and improve the accuracy of detection.

[0049] Furthermore, the container 1 includes a first cylinder 11 and a second cylinder 12, a detection chamber is formed in the first cylinder 11, and an installation chamber is formed in the second cylinder 12, the first cylinder 11 is provided with an internal thread, and the second cylinder 12 is provided with an external thread, the first cylinder 11 and the second cylinder 12 are connected by threaded locking, which is convenient for disassembly and cleaning of the internal structure, and the detection chamber has two optional structures, namely, a chamber for immersion in water and a chamber for connecting to a water pump on shore (not shown in the figure), and by rotating, disassembling and switching the two detection chambers, two working modes of underwater measurement and water pumping measurement used with a water pump on shore can be realized.

[0050] Furthermore, a lifting ring 128 is provided on the top of the detector, and an external cable is connected to the detector through the lifting ring 128. The detector can be connected to an above-water platform or manually held by the cable to perform in-situ detection at different water depths.

[0051] Furthermore, a filter screen 115 is provided on the first opening 111 , the second opening or the third opening 113 , and the filter screen 115 is used to prevent larger debris in the water body from entering the detection cavity.

[0052] The water body detector of the present invention can realize real-time detection of multiple components such as phycocyanin, chlorophyll, CDOM, turbidity, etc. in natural water, avoiding the limitation of existing instruments that a single device detects a single component at the same time; and by detecting the turbidity in the actual application environment, turbidity correction processing of the collected data is performed; the bandpass filter 124 band selection avoids the fluorescence peak band of each component, avoiding the influence of overlapping fluorescence signals of each component on the detection accuracy; combined with the design of four-channel simultaneous observation, the observation efficiency of the water body detector is improved; the observation data completes analog-to-digital conversion inside the instrument, improving the anti-interference ability of the instrument.

[0053] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terms used are illustrative and exemplary, rather than restrictive. Since the present invention can be embodied in a variety of forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims, so all changes and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. An in-situ algae detector with turbidity correction, characterized in that: The invention comprises a container, wherein a detection cavity and an installation cavity are formed in the container, the detection cavity provides a detection environment for water body detection, the detection cavity and the installation cavity are not connected with each other, a water inlet for external water to enter the detection cavity is opened on the container, a light source is arranged in the detection cavity, a water body component detection channel and a turbidity detection channel are arranged at one end of the installation cavity close to the detection cavity, during detection, the light in the detection cavity can enter the water body component detection channel and the turbidity detection channel, a detection unit is installed in the installation cavity, the detection unit detects the composition and turbidity of the water body to be detected through the water body component and turbidity detection channels, and corrects the detection signals of other water quality components according to the collected turbidity information.

2. The in-situ algae detector with turbidity correction according to claim 1, characterized in that: A mounting plate is provided at one end of the mounting cavity close to the detection cavity, and a water component detection channel and a turbidity detection channel are both provided on the mounting plate. A window piece is provided between the mounting plate and the detection cavity, and the window piece is sealed and connected to the container. Light in the detection cavity can pass through the window piece into the water component and turbidity detection channels.

3. The in-situ algae detector with turbidity correction according to claim 2, characterized in that: There are three water component detection channels, and the three water component detection channels correspond one to one to detect phycocyanin, chlorophyll, and CDOM in the water.

4. The in-situ algae detector with turbidity correction according to claim 3, characterized in that: Three water component detection channels and a turbidity detection channel are evenly arranged in a circle on the mounting plate.

5. The in-situ algae detector with turbidity correction according to claim 2, characterized in that: The invention also comprises a cleaning mechanism arranged in the container, and the cleaning mechanism is used for cleaning the window sheet.

6. The in-situ algae detector with turbidity correction according to claim 5, characterized in that: The cleaning mechanism comprises a driving motor arranged in the installation cavity and a cleaning brush located in the detection cavity and used for cleaning the window sheet. The output end of the driving motor passes through the window sheet and is connected with the cleaning brush.

7. The in-situ algae detector with turbidity correction according to claim 1, characterized in that: A first opening leading to the detection cavity is opened at the bottom of the container, and a filter covering the first opening is arranged at the bottom of the container.

8. The in-situ algae detector with turbidity correction according to claim 7, characterized in that: The side wall of the container is provided with a second opening leading to the detection cavity, the side wall of the container is provided with a light shield covering the second opening, the light shield is provided with a third opening, and the second opening and the third opening are arranged alternately.

9. The in-situ algae detector with turbidity correction according to claim 1, characterized in that: The installation cavity is provided with a data acquisition circuit, and also includes a bandpass filter and a photoelectric detector. The bandpass filter and the photoelectric detector are sequentially arranged in a water component detection channel and a turbidity detection channel in a direction away from the detection cavity.

10. The in-situ algae detector with turbidity correction according to claim 1, characterized in that: The irradiation direction of the light source is perpendicular to the directions of the water component detection channel and the turbidity detection channel.

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