In-situ monitoring device and method for suspended matter concentration based on piezoelectric effect

Abstract

A kind of in-situ monitoring device and method of suspended solids concentration based on piezoelectric effect, including spherical sensor, flow rate measuring unit, signal processing unit and power supply and data transmission unit.Spherical sensor built-in piezoelectric ceramic sheet, its impact surface is directly exposed to water flow, protected by sealed shell;Flow rate measuring unit synchronously acquires real-time flow rate by external speed measuring device, and with piezoelectric ceramic sheet is kept within the preset interval.Signal processing unit processes the charge signal generated by piezoelectric ceramic sheet to obtain total electric signal, extracts the pure water flow reference signal corresponding to current flow rate based on pre-stored bivariate calibration database, deducts flow rate coupling component from total electric signal to calculate suspended solids exclusive signal, and then inverses concentration through function model.Power supply and data transmission unit supplies power, and transmits concentration data to external equipment through wired or wireless mode.The device solves the problems of traditional technology, such as complex operation, easy to be disturbed, etc., and is suitable for long-term in-situ monitoring of water body suspended solids concentration.

Description

TECHNICAL FIELD

[0001] The present application relates to hydrological monitoring technology, in particular to a suspended matter concentration in-situ monitoring device and method based on piezoelectric effect. BACKGROUND

[0002] The suspended matter concentration monitoring in river, lake and ocean environment is the core parameter of hydrological resource management, water conservancy engineering safety and ecological environment protection. Real-time acquisition of in-situ suspended matter data has great significance for flood warning, reservoir sedimentation evaluation, channel management and water quality research. The traditional method relying on manual sampling and laboratory analysis has significant lag, which is difficult to capture the dynamic change process of suspended matter concentration, therefore, the development of high-precision and high-reliability in-situ continuous monitoring technology has become an urgent need in the industry.

[0003] The current mainstream suspended matter detection technology faces many problems. Experimental detection method (such as drying method, centrifugal method) needs manual sampling and transportation, which is easy to cause data distortion due to sample pollution and sedimentation stratification, and is time-consuming and lengthy, which cannot meet the real-time monitoring demand. In-situ optical method (transmission / scattering light method) is interfered by plankton, organic particles and color in water body, the signal is saturated at high concentration, and the consistency of measurement results of different devices is poor. Acoustic method (such as Doppler / echo intensity method) relies on flow rate to indirectly calculate concentration, the device cost is high, and the precision decays due to sensor drift during long-term deployment. These defects jointly restrict the in-situ continuous monitoring of suspended matter concentration.

[0004] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore can include information that does not constitute the prior art known to those of ordinary skill in the art. SUMMARY

[0005] The main purpose of the present application is to overcome the defects in the above background technology, provide a suspended matter concentration in-situ monitoring device and method based on piezoelectric effect, and realize long-term, high-precision and anti-interference in-situ continuous monitoring of water suspended matter concentration.

[0006] To achieve the above purpose, the present application adopts the following technical solutions:

[0007] A suspended matter concentration in-situ monitoring device based on piezoelectric effect, comprising:

[0008] A spherical sensor with a built-in piezoelectric ceramic sheet, the impact surface of which is directly exposed to the water flow environment, and protection is realized through a sealed shell;

[0009] A flow rate measuring unit synchronously collects real-time flow rate through an external speed measuring device, and the piezoelectric ceramic sheet is kept within a preset distance;

[0010] a signal processing unit configured to process the charge signal generated by the piezoelectric ceramic sheet to obtain a total electric signal, separate a flow rate coupling component and a suspended matter specific signal from the total electric signal, and calculate suspended matter concentration data according to the suspended matter specific signal;

[0011] a power supply and data transmission unit configured to supply power to each component and transmit the processed suspended matter concentration data to an external device through wired or wireless transmission;

[0012] The signal processing unit is configured to:

[0013] extract a pure water flow reference signal corresponding to the current flow rate based on a pre-stored bivariate calibration database;

[0014] subtract the interference of the flow rate coupling component from the total electric signal to calculate the suspended matter specific signal;

[0015] invert the suspended matter concentration value through a function model.

[0016] Further, the lead area of the piezoelectric ceramic sheet is sealed by a conductive silicone layer;

[0017] The sealed shell realizes underwater protection level through fastening structure, and the surface integrates anti-corrosion accessories.

[0018] Further, the signal processing unit includes a charge amplifier, a band-pass filter for setting a passband, and a high-precision ADC module connected in sequence;

[0019] The signal processing unit is integrated into an MCU circuit board, the MCU circuit board is entirely filled with waterproof material, and the speed measuring device is connected through a sealed interface.

[0020] Further, the pre-stored bivariate calibration database is constructed through the following cross-calibration experiment:

[0021] Different concentration gradient samples are configured under constant flow rate, and piezoelectric signals are recorded;

[0022] Adjust different flow rate gradients under constant concentration and record piezoelectric signals;

[0023] Fit the bivariate function relationship and store the pure water flow reference signal mapping table.

[0024] Further, an online verification mechanism is configured to compare the concentration value through an external turbidimeter, dynamically adjust the flow rate coupling correction coefficient, and update the database.

[0025] Further, the data transmission rod of the power supply and data transmission unit is built-in cable, realizing wired and wireless dual-mode transmission.

[0026] Further, the piezoelectric ceramic sheet is fixed to the inside of the sealed shell by conductive adhesive and the impact surface is opposite to the water flow direction.

[0027] The speed measuring device is installed upstream of the ball-shaped sensor.

[0028] A method for in-situ monitoring of suspended solids concentration based on piezoelectric effect, using the device, the method comprising the following steps:

[0029] Synchronously collecting the total electric signal generated by the piezoelectric ceramic sheet under the impact of water flow and suspended solids and processed, and the real-time flow rate measured by the speed measuring device;

[0030] Calling the pre-stored database to extract the pure water flow reference signal corresponding to the current flow rate;

[0031] Subtracting the flow rate coupling component from the total electric signal to calculate the suspended solids exclusive signal;

[0032] Inputting the exclusive signal into the pre-stored function model to output the suspended solids concentration value.

[0033] Further, the construction of the pre-stored database comprises:

[0034] Performing a double-variable cross-calibration experiment:

[0035] Recording the piezoelectric signal of the concentration gradient change under the condition of fixed flow rate;

[0036] Recording the piezoelectric signal of the flow rate gradient change under the condition of fixed concentration;

[0037] Fitting the double-variable function relationship based on the experimental data and storing the pure water flow reference signal mapping table.

[0038] Further, the method further comprises:

[0039] Periodically verifying the concentration value by an external turbidimeter, and dynamically adjusting the correction coefficient and updating the database when the deviation exceeds the allowed range.

[0040] The present application has the following beneficial effects:

[0041] The application provides a suspended matter concentration in-situ monitoring device and method based on a piezoelectric effect, provides a suspended matter concentration monitoring solution with high reliability and high precision and suitable for long-term in-situ continuous monitoring, and significantly improves the data quality and efficiency of hydrological monitoring. Wherein, the piezoelectric ceramic sheet exposed inside the spherical sensor bears the impact of water flow and suspended matter, cooperates with the synchronous acquisition of flow rate by the flow rate measuring device and carries out signal processing, on the basis of constructing a double-variable calibration database, the concentration is inverted through the model and is transmitted in real time, the problems of complex operation, easy interference and poor long-term stability of the traditional suspended matter detection technology are solved, especially the defects of multiple steps and low space-time precision of the traditional river suspended matter concentration measurement method are overcome, and the problems of complex environment background and high equipment cost faced by the optical and acoustic measurement methods are avoided; the application directly senses the physical impact of water flow and suspended matter particles by using a single ceramic piezoelectric sheet to generate an electric signal directly related to the concentration, cooperates with the double-variable calibration database and flow rate-signal separation processing to eliminate flow rate interference, cooperates with the embedded low-power circuit and waterproof structure to realize long-term, continuous and high-precision in-situ monitoring, is suitable for long-term in-situ monitoring of suspended matter concentration of rivers, lakes and offshore water bodies, and provides reliable technical support for suspended matter dynamics research and efficient management of hydrology and water resources.

[0042] Other beneficial effects of the embodiments of the application will be further described below. BRIEF DESCRIPTION OF DRAWINGS

[0043] Figure 1 Fig. 1 is a schematic diagram of the suspended matter concentration in-situ monitoring device of the embodiments of the application.

[0044] Figure 2 Fig. 3 is a schematic diagram of the layout of the spherical piezoelectric ceramic sheet in the embodiments of the application.

[0045] Figure 3 Fig. 5 is a test flowchart of the embodiments of the application.

[0046] REFERENCE NUMERALS:

[0047] 1, spherical sensor; 2, corrosion-resistant fitting; 3, data transmission rod; 4, cable; 5, power supply and data transmission unit; 6, flow rate measuring device; 21, piezoelectric ceramic sheet; 22, conductive silicone layer; 23, sealed shell; 24, data transmission line; 25, data transmission rod inner cavity; 26, MCU circuit board. DETAILED DESCRIPTION

[0048] The embodiments of the application are described in detail below. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope of the application and its applications.

[0049] It is to be understood that when an element is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or indirectly on or connected to the other element by way of one or more other elements. In addition, the word "connected" can be used herein to refer to an electrical or structural connection, but can also be used to refer to a coupling or a relationship of one element to another element.

[0050] It is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like as referring to the orientation or position of an item specified by the terms are based on the orientation or position as shown in the drawings, and are used only for the purpose of convenience and simplicity of description and are not intended to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be construed as limiting the application.

[0051] In addition, the terms "first", "second", "third", etc. are used herein only to describe different instances, and are not used to indicate or imply relative importance or a number of the specified technical features. Therefore, the features defined with "first", "second", etc. can explicitly or implicitly include one or more of the features. In the description of the embodiments of the application, the meaning of "a plurality of" is two or more, unless otherwise specifically limited.

[0052] In view of the problems of traditional river suspended substance concentration measurement methods, such as many steps and low space-time precision, and the problems of optical and acoustic measurement methods, such as complex environment background and high equipment cost, the application provides a suspended substance concentration in-situ monitoring device and method based on piezoelectric effect.

[0053] Referring to Figure 1 and Figure 2The embodiment of the present application is based on the piezoelectric effect of suspended matter concentration in-situ monitoring device, including spherical sensor 1, flow rate measuring unit, signal processing unit, power supply and data transmission unit: the piezoelectric ceramic sheet 21 is built-in in the spherical sensor 1, the impact surface is directly exposed to the water flow environment, and protection is realized through the sealed shell 23; the signal processing unit is used for processing the charge signal generated by the piezoelectric ceramic sheet 21 to obtain the total electric signal, separating the flow rate coupling component and the suspended matter exclusive signal in the total electric signal, and calculating the suspended matter concentration data according to the suspended matter exclusive signal; the flow rate measuring unit synchronously collects real-time flow rate through the external speed measuring device 6 (such as a small Doppler speed measuring device), and keeps the piezoelectric ceramic sheet 21 within the preset interval; the power supply and data transmission unit 5 is used for power supply for each component, and transmits the processed suspended matter concentration data to the external equipment through wired or wireless transmission; wherein the signal processing unit is configured to: extract the pure water flow reference signal corresponding to the current flow rate based on the pre-stored double-variable calibration database; subtract the interference of the flow rate coupling component from the total electric signal to calculate the suspended matter exclusive signal; and inverse the suspended matter concentration value through the function model.

[0054] Referring to Figure 2 In some embodiments, the lead area of the piezoelectric ceramic sheet 21 is sealed by a conductive silicone layer 22; the sealed shell 23 realizes the underwater protection level through the fastening structure, and the surface integrates the anti-corrosion accessory 2.

[0055] Referring to Figure 2 In some embodiments, the signal processing unit is integrated in the MCU circuit board 26, the MCU circuit board 26 is entirely filled with waterproof material, and the speed measuring device 6 is connected through a sealed interface. The signal processing unit includes a charge amplifier, a band-pass filter with a set passband, and a high-precision ADC module connected in sequence.

[0056] Referring to Figure 1 and Figure 2 In some embodiments, in the spherical sensor 1, the piezoelectric ceramic sheet 21 is fixed to the inside of the sealed shell 23 through a conductive adhesive and the impact surface is directly opposite to the water flow direction. The speed measuring device 6 is installed upstream of the spherical sensor 1, such as 20 cm away.

[0057] Referring to Figure 1 and Figure 2 In some embodiments, the data transmission rod 3 of the power supply and data transmission unit is built-in cable 4, realizing wired and wireless dual-mode transmission.

[0058] In some embodiments, the pre-stored double-variable calibration database is constructed through the following cross-calibration experiment: configuring different concentration gradient samples under constant flow rate and recording piezoelectric signals; adjusting different flow rate gradient under constant concentration and recording piezoelectric signals; fitting the double-variable function relationship and storing the pure water flow reference signal mapping table.

[0059] In some embodiments, an online verification mechanism is configured to compare concentration values ​​with an external turbidimeter, dynamically adjust the flow rate coupling correction coefficient, and update the database.

[0060] See Figure 3 This invention also provides an in-situ monitoring method for suspended solids concentration based on the piezoelectric effect, using the monitoring device described in the foregoing embodiments. The monitoring method includes the following steps:

[0061] The total electrical signal generated by the impact of water flow and suspended matter on the piezoelectric ceramic plate 21 and processed thereon is collected simultaneously, along with the real-time flow velocity measured by the velocity measuring device 6.

[0062] Retrieve the pure water flow reference signal corresponding to the current flow rate from the pre-stored database;

[0063] The velocity coupling component is subtracted from the total electrical signal to calculate the suspended solids-specific signal;

[0064] The specific signal is input into a pre-stored function model, and the suspended solids concentration value is output.

[0065] In some embodiments, the construction of the pre-stored database includes: performing bivariate cross-calibration experiments: 1) recording piezoelectric signals of concentration gradient changes under fixed flow rate conditions; 2) recording piezoelectric signals of flow rate gradient changes under fixed concentration conditions. A bivariate function relationship is fitted based on the experimental data, and a pure water flow reference signal mapping table is stored.

[0066] In some embodiments, the method further includes: periodically verifying the concentration value using an external turbidimeter, and dynamically adjusting the correction coefficient and updating the database when the value exceeds the allowable deviation range.

[0067] The following describes specific embodiments of the present invention.

[0068] A device and method for in-situ monitoring of suspended solids concentration based on the piezoelectric effect are disclosed, addressing the problems of complex operation, susceptibility to interference, and poor long-term stability of traditional suspended solids detection technologies. The device includes a spherical sensor 1 with an exposed piezoelectric ceramic plate 21 inside, which withstands the impact of water flow and suspended solids, and is protected by an IP68-level sealed shell 23 made of titanium alloy. An externally mounted Doppler velocity measuring device (velocity measuring device 6) with a 20cm spacing simultaneously collects flow velocity data. An MCU circuit board 26 performs signal processing, and a lithium thionyl chloride battery supports continuous operation. The method includes: constructing a bivariate calibration database (fitting a function through cross-experiments of fixed flow velocity with varying concentration and fixed concentration with varying flow velocity). S = f ( v , C Based on the above, the on-site flow rate is considered. v Separate the piezoelectric signal of suspended matter. α = (flow velocity correction coefficient) is coupled to the flow velocity; the model is inverted C g S tss ) and transmitted in real time. The present application solves the problems of multiple steps and low spatial and temporal accuracy faced by traditional river suspended solids concentration measurement methods, and avoids the problems of complex environmental background and high equipment cost encountered by optical and acoustic measurement methods, and is suitable for long-term in-situ monitoring of suspended solids concentration in rivers, lakes and nearshore water bodies.

[0069] Specifically, the in-situ monitoring device for suspended solids concentration based on piezoelectric effect comprises:

[0070] The spherical sensor 1 is internally provided with a single circular piezoelectric ceramic sheet 21, the impact surface of which is directly exposed to the water flow environment and is fixed to the inside of the spherical sealed shell 23 made of titanium alloy by epoxy conductive adhesive;

[0071] The signal processing unit is integrated on the MCU circuit board 26, including a charge amplifier, a band-pass filter with a passband of 0.1-10 kHz, and a 24-bit ADC module, and the entire circuit board is filled with polyurethane waterproof glue;

[0072] The flow velocity measurement unit is an external small Doppler velocity measurement device (velocity measurement device 6), which is installed at a distance of 20 cm from the piezoelectric ceramic sheet 21 and is connected to the MCU circuit board 26 through a sealed interface;

[0073] The power supply and data transmission unit 5 is a lithium sulfonyl chloride battery pack and a data transmission device, which is connected to the data transmission rod 3 of the built-in data transmission line 24 and supports RS-485 wired transmission and wireless transmission dual mode.

[0074] The piezoelectric ceramic sheet 21 is made of PZT-5H material, with a size of 10mm×10mm×0.5mm, a resonance frequency of 1MHz and a sensitivity of ≥5pC / N; when selecting the piezoelectric ceramic sheet, the water flow impact signal frequency band can be adapted, and the filter passband matches the high sensitivity interval of the ceramic sheet;

[0075] The sealed shell 23 made of titanium alloy is a Φ120mm×120mm sealed cabin, which is fastened by an O-shaped sealing ring and ≥30N·m torque bolts to achieve IP68 protection level and ≥100m pressure resistance depth. The pressure resistance depth can be designed based on the strength, wall thickness and sealing structure of the shell material to ensure the structural safety in deep water environment.

[0076] The lead area of the piezoelectric ceramic sheet 21 is covered by a conductive silicone layer 22;

[0077] The shell surface is integrated with corrosion-resistant accessories 2.

[0078] ​​​A method for in-situ monitoring of suspended solids concentration based on the piezoelectric effect includes the following steps:

[0079] Synchronous signal acquisition:

[0080] The total electrical signal is obtained through the piezoelectric ceramic sheet 21. S tss Real-time flow velocity is obtained through a Doppler velocity measuring device (velocity measuring device 6). v ;

[0081] Suspended matter signal separation:

[0082] Call the pre-stored database to extract the current flow rate v v Corresponding pure water flow reference signal S flow（v） Calculate the suspended matter signal according to the formula:

[0083]

[0084] in α It is the velocity coupling correction coefficient; it can be the velocity coupling correction coefficient fitted by the calibration experiment, and can be dynamically adjusted according to online verification.

[0085] Concentration inversion:

[0086] Will S tss Input pre-stored function model C = g ( S tss ), outputs the suspended solids concentration value.

[0087] The pre-stored database is constructed through the following steps:

[0088] Cross-calibration experiment:

[0089] constant flow rate vi Under these conditions, concentration gradient samples (0–500 mg / L) were prepared, and piezoelectric signals were recorded.

[0090] Fixed concentration Ck Under controlled flow rate gradients (0.5–3.0 m / s), the signal was recorded. In fixed concentration experiments, the sample can be injected at a constant rate and allowed to mix thoroughly before the concentration is measured simultaneously as the true value.

[0091] Database generation:

[0092] Fitting a bivariate function S = f ( v , C Error tolerance ε ≤±5%, and store pure water flow reference signal. Sflow（v） .

[0093] Also included is an online verification step:

[0094] Periodically compare concentration values by laser scattering turbidimeter, when deviation > ± 5%, dynamically adjust the coefficient α And update the database. The external turbidimeter can be calibrated periodically to monitor accuracy over time.

[0095] The battery pack nominal voltage 3.6V, capacity 19Ah, support ≥ 18 months continuous operation.

[0096] The following details and principles of the implementation of the suspended matter concentration in-situ monitoring device and method based on piezoelectric effect are described in detail.

[0097] 1. Overall structural configuration

[0098] As Figure 1 shown, the device body is a spherical sensor 1, which contains a piezoelectric sensing unit, a processing circuit and a sealing structure in the internal core. The piezoelectric sensing unit adopts a single circular piezoelectric ceramic sheet 21, preferably PZT-5H material, with a size of 10mm x 10mm x 0.5mm and a resonant frequency of 1-3MHz. The piezoelectric ceramic sheet is fixed inside the titanium alloy spherical sealing shell 23 by epoxy conductive adhesive, with its impact surface facing the water flow direction to achieve direct force.

[0099] The waterproof sealing shell 23 is a sealed cabin with a diameter of Φ120mm x 120mm, with an O-ring at one end and fastened by bolts. The surface of the shell is integrated with corrosion-resistant fittings 2 to cope with long-term underwater environment.

[0100] Circuit and signal processing, see Figure 2 , MCU circuit board 26 is set in the inner cavity of the shell, preferably a low-power microcontroller. The signal processing chain is connected in the following order: charge amplifier, receiving the charge signal generated by the piezoelectric ceramic sheet 21; band-pass filter, set 0.1-10kHz passband to filter out low-frequency turbulent noise and high-frequency interference; 24-bit ADC module, converts the filtered signal to digital quantity. The entire circuit board is filled with polyurethane waterproof glue, and the lead area is covered with a conductive silicone layer 22 to achieve waterproof insulation.

[0101] Auxiliary functional units, flow rate measurement is realized by external small Doppler velocity measurement device (velocity measurement device 6), which is installed at a distance of 20cm from the piezoelectric unit and synchronously transmits flow rate data to MCU through airtight interface. The power supply system uses lithium sulfonyl chloride battery pack (integrated in power supply and data transmission unit 5), which can support continuous operation. Data transmission is completed through the data transmission rod of the built-in cable 4, compatible with underwater cable direct connection and LoRa wireless transmission dual mode.

[0102] The titanium alloy sealed outer shell 23 provides high-strength mechanical protection to prevent damage to the piezoelectric element from external forces. The conductive silicone layer 22 selectively covers the lead area, achieving electrical isolation while keeping the impact surface exposed. The rigid connection interface formed by the cured epoxy conductive adhesive ensures that the impact force of suspended particles is transmitted to the piezoelectric material without damage.

[0103] 2. Dynamic calibration database construction process

[0104] Cross-disciplinary experimental design

[0105] Sample preparation: Sediments were collected from rivers, lakes, etc., dried, ground, and sieved (controlling the particle size range, such as 50–200 μm), and gradient concentration samples were prepared with filtered water.

[0106] Experimental environment: The experiment was conducted in a controllable circulating water tank with a constant water temperature (±1℃) to avoid temperature interference with the piezoelectric signal.

[0107] Table 1: Dynamic Calibration Experiment Design Table

[0108]

[0109] Key control points: Each experiment was repeated three times, and the average signal value was taken to eliminate random errors. Laser scattering was used to simultaneously verify the true value of suspended solids concentration.

[0110] Database generation and function fitting

[0111] Data preprocessing: Remove outliers (signal fluctuations > ±10%) and normalize the signal SS.

[0112] piezoelectric signal S It is the flow rate v and concentration C Functions:

[0113] S=f(v,C)+ε(ε≤±5%)

[0114] 3. Signal separation and concentration inversion mechanism

[0115] On-site measurement process. Synchronous acquisition: Total output signal from piezoelectric equipment. S total Real-time flow velocity measured by Doppler instrument v Signal stripping: Query the database to extract the current flow rate. v Corresponding pure water flow reference signal S flow（v） ; Calculate the specific signal for suspended matter: ( α (This is the flow velocity coupling correction factor).

[0116] Concentration inversion: Stss Substitute function model C = g ( S tss ), output concentration value.

[0117] Workflow

[0118] Device deployment and activation, fix the spherical sensor 1 on the buoy, make the inductive device (piezoelectric ceramic sheet 21) impact surface face the main flow direction; install a small Doppler velocity measuring device 20 cm upstream of the sensor, connect the MCU circuit board 26 through a waterproof interface; start the battery and data transmission device, system self-checking includes: piezoelectric signal baseline drift verification (threshold value ±0.2mV); Doppler flow velocity zero point calibration (threshold value ±0.05m / s).

[0119] Real-time data synchronous acquisition, piezoelectric signal generation: water flow and suspended particles impact the surface of piezoelectric ceramic sheet 21, generating charge signals.

[0120] Signal conditioning, charge signals are transmitted to the charge amplifier (gain 1000x) through the conductive silicone layer 22; the band-pass filter (passband 0.1-10kHz) filters out low-frequency turbulence and high-frequency interference; 24-bit ADC module outputs digitized total electric signal S total ; flow velocity synchronous acquisition: Doppler device (velocity measuring device 6) real-time measurement and output flow velocity v .

[0121] Suspended solids exclusive signal separation, MCU calls pre-stored database and performs the following operations:

[0122] 1. Based on the current flow velocity v , query the pure water flow reference signal S flow（v） ;

[0123] 2. Calculate the suspended solids component signal according to the formula:

[0124] Concentration inversion and output, input the pre-stored bivariate function model: S tss = C = g ( S tss )

[0125] Concentration data is uploaded through data transmission rod 3, modes include RS-485 wired transmission (through waterproof cable 4) and LoRa wireless transmission (integrated in power supply and data transmission unit 5).

[0126] Online verification and fault-tolerant processing, periodic comparison is performed by a laser scattering turbidimeter, when the concentration deviation is > ± 5%, the coefficient is adjusted α and update the database.

[0127] In summary, the in-situ suspended matter concentration monitoring device and method based on piezoelectric effect provided by the present application fundamentally solves the core problems of complex operation, easy interference and poor long-term stability of traditional suspended matter detection technology by directly sensing the physical impact of water flow and suspended matter particles with a piezoelectric ceramic sheet to generate an electric signal, eliminating flow rate interference by combining a double-variable calibration database and flow rate-signal separation processing, and cooperating with a waterproof sealing structure and an embedded low-power consumption system. Compared with the experimental detection method, in-situ continuous monitoring is realized, avoiding sample pollution and data lag; compared with the optical method, the interference of plankton and signal saturation defects are avoided; compared with the acoustic method, the concentration does not need to be indirectly calculated, and the equipment cost and drift risk are reduced. The device can realize long-term, high-precision and anti-interference real-time monitoring of suspended matter concentration in rivers, lakes and nearshore water bodies, providing reliable technical support for hydrological warning, silt evaluation and water quality management.

[0128] The above is a further detailed description of the present application in combination with specific / preferred embodiments, and cannot be regarded as limiting the specific implementation of the present application to these descriptions. For ordinary skilled persons in the technical field to which the present application belongs, without departing from the concept of the present application, they can make several alternatives or modifications to the described embodiments, and these alternatives or modifications shall be regarded as falling within the protection scope of the present application. In the description of the present specification, the description of the terms "an embodiment", "some embodiments", "preferred embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In the case of not contradicting each other, the skilled person in the art can combine and combine the different embodiments or examples described in the present specification and the features of the different embodiments or examples. Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, replacements and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A device for in-situ monitoring of suspended matter concentration based on piezoelectric effect, characterized in that, The device comprises: a spherical sensor (1) with a built-in piezoelectric ceramic sheet (21) whose impact surface is directly exposed to the water flow environment and is protected by a sealed shell (23); a flow rate measuring unit that synchronously collects real-time flow rate through an external speed measuring device (6) and keeps the piezoelectric ceramic sheet (21) within a preset distance; a signal processing unit for processing the charge signal generated by the piezoelectric ceramic sheet (21) to obtain total electric signal, separating the flow rate coupling component from the suspended matter exclusive signal in the total electric signal, and calculating the suspended matter concentration data according to the suspended matter exclusive signal; a power supply and data transmission unit for supplying power to each component and transmitting the processed suspended matter concentration data to external equipment through wired or wireless transmission; wherein the signal processing unit is configured to: extract the pure water flow reference signal corresponding to the current flow rate based on the pre-stored two-variable calibration database; subtract the interference of the flow rate coupling component from the total electric signal to calculate the suspended matter exclusive signal; invert the suspended matter concentration value through the two-variable function model established based on the pre-stored two-variable calibration database; the pre-stored two-variable calibration database is constructed through the following cross-calibration experiment: configure samples with different concentration gradients under constant flow rate and record the piezoelectric signal; adjust different flow rate gradients under constant concentration and record the piezoelectric signal; fit the two-variable function relationship, and store the pure water flow reference signal mapping table based on the two-variable function relationship for extracting the pure water flow reference signal corresponding to the current flow rate.

2. The device according to claim 1, wherein: the lead area of the piezoelectric ceramic sheet (21) is sealed by a conductive silicone layer (22); the sealed shell (23) achieves underwater protection level through fastening structure, and the surface is integrated with anti-corrosion fittings (2).

3. The device according to claim 1 or 2, wherein: the signal processing unit includes sequentially connected charge amplifier, band-pass filter with set passband, and high-precision ADC module; the signal processing unit is integrated on the MCU circuit board (26), the MCU circuit board (26) is entirely filled with waterproof material, and the speed measuring device (6) is connected through a sealed interface.

4. The device according to claim 1 or 2, wherein: an online verification mechanism is configured to dynamically adjust the flow rate coupling correction coefficient and update the database by comparing the concentration value with an external turbidimeter.

5. The device according to claim 1 or 2, wherein: the data transmission rod (3) of the power supply and data transmission unit is internally provided with a cable (4) to realize wired and wireless dual-mode transmission.

6. The device according to claim 1 or 2, wherein: the piezoelectric ceramic sheet (21) is fixed inside the sealed shell (23) with the impact surface facing the water flow direction; the speed measuring device (6) is installed upstream of the spherical sensor (1).

7. A method for in-situ monitoring of suspended matter concentration based on piezoelectric effect, using the device according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: synchronously collecting the total electric signal generated by the piezoelectric ceramic sheet (21) under the impact of water flow and suspended matter and obtained after processing, and the real-time flow rate measured by the speed measuring device (6); calling the pre-stored database to extract the pure water flow reference signal corresponding to the current flow rate; Subtracting the flow rate coupling component from the total signal, the suspended solids exclusive signal is calculated; Inputting the exclusive signal into the pre-stored function model, the suspended solids concentration value is outputted.

8. The method of claim 7, wherein, The construction of the pre-stored database includes: Performing a double-variable cross calibration experiment: - Recording the piezoelectric signal of the concentration gradient change under the condition of fixed flow rate; - Recording the piezoelectric signal of the flow rate gradient change under the condition of fixed concentration; Fitting the double-variable function relationship based on the experimental data and storing the pure water flow reference signal mapping table.

9. The method according to claim 7 or 8, characterized in that, Further comprising: Periodically verifying the concentration value by an external turbidimeter, and dynamically adjusting the correction coefficient and updating the database when the deviation exceeds the allowed range.

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