Method for concentrating plankton in water sample, tangential flow filtering system, device, equipment and medium

Abstract

The invention discloses a method for concentrating plankton in a water sample, a tangential flow filtering system, a tangential flow filtering device, equipment and a medium, and relates to the technical field of water sample concentration.The method comprises the steps that based on a current control mode, a rotating speed instruction is sent to a diaphragm pump in the tangential flow filtering system to control the diaphragm pump to adjust the current rotating speed, pumping the to-be-treated water sample into a spiral filter based on the current rotating speed; based on the tangential flow velocity and the transmembrane pressure, sending a proportional valve opening degree adjusting instruction to a proportional valve to adjust the opening degree of the proportional valve, control the to-be-treated water sample to be subjected to tangential flow circulating filtration in the tangential flow filtration system, control the tangential flow velocity and / or the transmembrane pressure of the to-be-treated water sample, and concentrate the to-be-treated water sample to a target volume within a preset time, the recovery rate of the plankton in the water sample to be treated is controlled to reach a preset recovery rate threshold value. A to-be-treated water sample is controlled to flow at a high speed in the membrane tube, water molecules penetrate through the membrane wall under the driving of pressure, plankton is intercepted and continuously circulates along with a main body liquid flow, and thus rapid concentration is realized.

Description

Technical Field

[0001] This invention relates to the field of water sample concentration technology, and particularly to a method for concentrating plankton in water samples, a tangential flow filtration system, apparatus, equipment, and media. Background Technology

[0002] Plankton are a key component of ecosystems, and methods, tools, and procedures for monitoring the dynamic changes of plankton populations are of great significance to biological and ecological research. To date, manual net collection and optical microscopy analysis of water samples remain the main methods for observing plankton. However, this traditional method requires 24-48 hours for sample concentration processing, which cannot meet the needs of rapid monitoring.

[0003] In recent years, deep learning technology has developed rapidly, and its neural network models have shown great promise in target tracking, recognition, and image classification in similar scenarios. This makes it possible to apply deep learning technology to plankton image recognition and establish an efficient and accurate intelligent plankton identification and counting system. However, most current automatic plankton detection and counting products are not equipped with efficient water sample pretreatment modules, requiring manual water sample fixation and concentration, or the fixation and concentration time is too long, resulting in untimely detection results. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide a method, tangential flow filtration system, apparatus, equipment, and medium for concentrating plankton in water samples, which can rapidly concentrate water samples in a short time. The specific solution is as follows:

[0005] In a first aspect, this application discloses a method for concentrating plankton in a water sample, applied to a preset controller in a tangential flow filtration system, comprising:

[0006] Based on the current control mode, a speed command is sent to the diaphragm pump in the tangential flow filtration system to control the diaphragm pump to adjust the current speed so that the water sample to be treated is pumped into the spiral filter in the tangential flow filtration system based on the current speed.

[0007] Based on the received tangential flow velocity and transmembrane pressure, a proportional valve opening adjustment command is sent to the proportional valve in the tangential flow filtration system. The opening of the proportional valve is adjusted according to the proportional valve opening adjustment command to control the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system. The tangential flow velocity and / or transmembrane pressure of the water sample to be treated are controlled to concentrate the water sample to be treated to a target volume within a preset time. The recovery rate of plankton in the water sample to be treated is controlled to reach a preset recovery rate threshold.

[0008] Optionally, the spiral filter is constructed by spirally winding and fixing filter membrane tubes with a filter pore size range of 0.3 to 3 μm and a filter tube diameter of 3 to 7 mm onto a membrane tube fixing post.

[0009] Optionally, the spiral filter is provided with an inlet, an outlet, a filtrate outlet, and an exhaust port;

[0010] Accordingly, controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system includes:

[0011] Air is expelled from the spiral filter through the vent, the water sample to be treated is pumped into the spiral filter from the inlet, the water sample to be treated is controlled to undergo tangential flow filtration in the tangential flow filtration system, the concentrated water sample flows out from the outlet and returns for circulation, and then the filtrate is discharged from the filtrate outlet.

[0012] Optionally, the tangential flow filtration system may also include a pressure sensor and a flow meter;

[0013] Accordingly, controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system, and controlling the tangential flow velocity and / or transmembrane pressure of the water sample to be treated, includes:

[0014] If the current control mode is pressure control mode, the transmembrane pressure is monitored by the pressure sensor and uploaded to the preset controller. Based on the difference between the transmembrane pressure and the preset pressure value, the speed of the diaphragm pump and / or the opening of the proportional valve are adjusted.

[0015] If the current control mode is the filtration rate control mode, the flow rate of the filtrate is monitored by the flow meter and the flow rate of the filtrate is uploaded to the preset controller. Based on the difference between the filtrate flow rate and the preset flow rate value, the speed of the diaphragm pump and / or the opening of the proportional valve are adjusted.

[0016] If the current control mode is normal control mode, the target tangential flow velocity and target proportional valve opening are determined based on the preset parameter optimization algorithm, so as to control the diaphragm pump to pump the water sample to be treated according to the target tangential flow velocity, and control the proportional valve to adjust the opening according to the target proportional valve opening.

[0017] Optionally, the step of determining the target tangential flow velocity and the target proportional valve opening based on the preset parameter optimization algorithm includes:

[0018] By setting tangential flow velocity and proportional valve opening as independent variables, and filtration time and recovery rate as response variables, a quadratic polynomial response surface model is established.

[0019] The quadratic polynomial response surface model is optimized using the expectation function method to obtain a combination of independent variables that satisfies the preset recovery rate constraint and the preset filtration time constraint. The current tangential velocity and the current proportional valve opening in the combination of independent variables are then determined as the target tangential velocity and the target proportional valve opening, respectively.

[0020] Optionally, the method for concentrating plankton in the water sample further includes:

[0021] Lugo's reagent was added to the concentrated water sample for fixation treatment to obtain a fixed concentrated water sample;

[0022] The concentrated water sample after fixation is stirred by a magnetic stirrer, and then the mixed water sample is sent to the image detection module for the identification and counting of plankton.

[0023] Secondly, this application discloses a tangential flow filtration system, comprising: a diaphragm pump, a spiral filter, a metering cup, a flow meter, a preset controller, a pressure sensor, and a proportional valve, wherein,

[0024] The inlet of the diaphragm pump is connected to the metering cup via a pipeline, the outlet of the diaphragm pump is connected to the inlet of the spiral filter, and the outlet of the spiral filter returns to the metering cup via a pipeline, forming a circulating concentration loop. The filtrate outlet of the spiral filter is connected to the flow meter, and the preset controller is electrically connected to the pressure sensor, the flow meter, the diaphragm pump, and the proportional valve, respectively.

[0025] The preset controller is used to issue a speed command to the diaphragm pump based on the current control mode to control the current speed of the diaphragm pump;

[0026] The diaphragm pump is used to pump the water sample to be treated in the metering cup into the spiral filter based on the current rotation speed;

[0027] The preset controller is used to receive the tangential flow velocity and transmembrane pressure sent by the flow meter and the pressure sensor installed on the pipeline of the circulation loop, respectively, so as to send a proportional valve opening adjustment command to the proportional valve based on the current control mode.

[0028] The proportional valve installed in the pipeline of the circulating concentration loop is used to receive the proportional valve opening adjustment command from the preset controller and adjust the proportional valve opening.

[0029] The preset controller is used to concentrate the plankton in the water sample to be treated in the metering cup to a target volume within a preset time by controlling the tangential flow rate and / or the transmembrane pressure, and to control the recovery rate of the plankton in the water sample to be treated to reach a preset recovery rate threshold.

[0030] The tangential flow filtration system further includes: an ultrasonic level sensor and a chlorophyll sensor, wherein...

[0031] The chlorophyll sensor is used to monitor the algae concentration in the water sample to be treated in the metering cup, and send the algae concentration to the preset controller so as to determine the target concentration factor based on the chlorophyll concentration-concentration factor curve;

[0032] The ultrasonic liquid level sensor is used to monitor the target liquid level in the metering cup and send the target liquid level to the preset controller so as to determine the target concentration factor based on the target liquid level.

[0033] Thirdly, the present invention discloses a plankton concentration device for water samples, which is applied to a preset controller in a tangential flow filtration system, comprising:

[0034] The water sample pumping module is used to send a speed command to the diaphragm pump in the tangential flow filtration system based on the current control mode to control the diaphragm pump to adjust the current speed so that the water sample to be treated is pumped into the spiral filter of the tangential flow filtration system based on the current speed.

[0035] The concentration module is used to send a proportional valve opening adjustment command to the proportional valve in the tangential flow filtration system based on the received tangential flow velocity and transmembrane pressure, so as to adjust the opening of the proportional valve based on the proportional valve opening adjustment command, thereby controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system, and controlling the tangential flow velocity and / or transmembrane pressure of the water sample to be treated, concentrating the water sample to be treated to a target volume within a preset time, and controlling the recovery rate of plankton in the water sample to reach a preset recovery rate threshold.

[0036] Fourthly, this application discloses an electronic device, comprising:

[0037] Memory, used to store computer programs;

[0038] A processor is used to execute the computer program to implement the steps of the aforementioned disclosed method for concentrating plankton in water samples.

[0039] Fifthly, this application discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the steps of the aforementioned disclosed method for concentrating plankton in water samples.

[0040] As can be seen, this application discloses a method for issuing a rotation speed command to the diaphragm pump in the tangential flow filtration system based on the current control mode, thereby controlling the diaphragm pump to adjust its current rotation speed so that the water sample to be treated is pumped into the spiral filter in the tangential flow filtration system based on the current rotation speed; and sending a proportional valve opening adjustment command to the proportional valve in the tangential flow filtration system based on the received tangential flow velocity and transmembrane pressure, so as to adjust the opening of the proportional valve based on the proportional valve opening adjustment command, thereby controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system, and controlling the tangential flow velocity and / or transmembrane pressure of the water sample to be treated, concentrating the water sample to be treated to a target volume within a preset time, and controlling the recovery rate of plankton in the water sample to reach a preset recovery rate threshold. Therefore, it is evident that the active, externally applied dynamic filtration method of tangential flow circulation filtration pumps the water sample into the system and causes it to flow at high speed within the membrane tube. Water molecules permeate through the membrane wall under pressure (filtrate), while plankton are trapped and continue to circulate with the main liquid flow, thus achieving rapid concentration and directly reducing pretreatment time from days to minutes. Furthermore, during the tangential flow circulation filtration process, by controlling and maintaining a suitable tangential flow rate, a sweeping effect is generated, effectively flushing the membrane surface and reducing the adsorption of plankton and concentration polarization on the membrane surface, achieving a high recovery rate. By controlling the transmembrane pressure and keeping it within a safe range, excessive pressure is avoided from squeezing and destroying plankton on the membrane wall, or damaging the morphology of fragile species due to excessive shear force. In this way, both high recovery rate and biological morphological integrity are achieved simultaneously, providing a high-quality, non-destructive sample basis for subsequent automated identification based on image recognition, ensuring the accuracy and reliability of monitoring data. Attached Figure Description

[0041] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0042] Figure 1 This is a flowchart of a method for concentrating plankton in water samples disclosed in this application;

[0043] Figure 2 This application discloses a specific method for concentrating plankton in water samples;

[0044] Figure 3 This is a flowchart of an online pretreatment method for plankton disclosed in this application;

[0045] Figure 4 This is a schematic diagram of a device for concentrating plankton in water samples disclosed in this application.

[0046] Figure 5 This is a structural diagram of an electronic device disclosed in this application. Detailed Implementation

[0047] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0048] Phytoplankton are a key component of ecosystems, and methods, tools, and procedures for monitoring phytoplankton population dynamics are of great significance to biological and ecological research. To date, manual net collection and optical microscopy analysis of water samples remain the primary methods for phytoplankton observation. However, these traditional methods require 24-48 hours of sample concentration processing, which cannot meet the needs of rapid monitoring. For example, patent number CN116296678A describes an automatic phytoplankton monitoring device and method for online phytoplankton monitoring. This method involves concentrating water samples through a process of fixation, natural settling for 24 hours, and extraction of the supernatant. This long pretreatment time prevents timely detection results.

[0049] In recent years, deep learning technology has developed rapidly, and its neural network models have shown great promise in target tracking, recognition, and image classification in similar scenarios. This makes it possible to apply deep learning technology to plankton image recognition and establish an efficient and accurate intelligent plankton identification and counting system. However, most current automatic plankton detection and counting products are not equipped with efficient water sample pretreatment modules, requiring manual water sample fixation and concentration, or the fixation and concentration time is too long, resulting in untimely detection results.

[0050] Therefore, the present invention provides a scheme for concentrating plankton in water samples, which can complete the rapid concentration treatment of water samples in a short time.

[0051] Reference Figure 1 As shown, this invention provides a method for concentrating plankton in a water sample, applied to a preset controller in a tangential flow filtration system, comprising:

[0052] Step S11: Based on the current control mode, a speed command is sent to the diaphragm pump in the tangential flow filtration system to control the diaphragm pump to adjust the current speed so that the water sample to be treated is pumped into the spiral filter in the tangential flow filtration system based on the current speed.

[0053] In this embodiment, according to the current control mode, the preset controller in the tangential flow filtration system sends a speed command matching the current control mode to the diaphragm pump in the tangential flow filtration system. The diaphragm pump is controlled to adjust its current speed according to the speed command. Then, at the adjusted current speed, the diaphragm pump pumps the water sample to be treated into the spiral controller in the tangential flow filtration system. The preset controller is a pre-programmed automated control device configured with optimization algorithms and multi-mode control logic, used to fully coordinate the diaphragm pump, proportional valve, pressure sensor and flow meter.

[0054] In this embodiment, the spiral filter is constructed by spirally winding and fixing filter membrane tubes with a pore size ranging from 0.3 to 3 μm and a tube diameter of 3 to 7 mm onto a membrane tube fixing column. It can be understood that, based on the size characteristics of plankton (zooplankton and phytoplankton), filter membrane tubes with a pore size of 0.3-3 μm and a tube diameter of 3-7 mm are selected and spirally wound and fixed onto the membrane tube fixing column to form a spiral filter. In this way, the water sample to be treated can be filtered through this spiral filter, retaining plankton on the membrane tubes, while water passes through the spiral filter and becomes a component of the filtrate.

[0055] Step S12: Based on the received tangential flow velocity and transmembrane pressure, a proportional valve opening adjustment command is sent to the proportional valve in the tangential flow filtration system to adjust the opening of the proportional valve, thereby controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system, and controlling the tangential flow velocity and / or transmembrane pressure of the water sample to be treated to concentrate the water sample to be treated to the target volume within a preset time, and controlling the recovery rate of plankton in the water sample to reach a preset recovery rate threshold.

[0056] In this embodiment, the spiral filter is provided with an inlet, an outlet, a filtrate outlet, and an exhaust port. Air is expelled from the spiral filter through the exhaust port. The water sample to be treated is pumped into the spiral filter from the inlet. The water sample to be treated is controlled to undergo tangential flow filtration in the tangential flow filtration system. The concentrated water sample flows out from the outlet and is returned for circulation. Then, the filtrate is discharged from the filtrate outlet. Understandably, the spiral filter is specifically equipped with an inlet, an outlet, and an vent. Therefore, during the filtration and concentration process in the tangential flow filtration system, firstly, if it is the first filtration cycle, air is expelled from the spiral filter through the vent. Then, the water sample to be treated is pumped into the spiral filter through the inlet. At this time, the preset controller sends a proportional valve opening adjustment command to the proportional valve in the tangential flow system based on the tangential flow velocity and transmembrane pressure fed back by the sensor under the current control mode. Then, based on the proportional valve opening adjustment command, the opening of the proportional valve is adjusted to control the water sample to be treated to undergo tangential flow filtration in the tangential flow filtration system at the current opening. Then, the concentrated water sample flows out from the outlet into the metering cup and returns to the system for the next cycle, with the filtrate discharged from the filtrate outlet. Thus, it can be seen that the diaphragm pump pumps the water sample to be treated into the inlet, the concentrated water sample flows out from the outlet, and the filtrate is discharged from the filtrate outlet.

[0057] In this embodiment, the tangential flow filtration system also includes a pressure sensor and a flow meter. It is understood that the tangential flow filtration system also includes sensors, specifically a pressure sensor and a flow meter, used to collect the transmembrane pressure and tangential flow rate during each filtration cycle. These collected signals are then uploaded to a preset controller, which adjusts the proportional valve opening based on the received transmembrane pressure and tangential flow rate. Specifically, the adjustment of the proportional valve opening follows three adjustment strategies under different control modes, as detailed below:

[0058] If the current control mode is pressure control mode, the transmembrane pressure is monitored by the pressure sensor and uploaded to the preset controller. Based on the difference between the transmembrane pressure and the preset pressure value, the speed of the diaphragm pump and / or the opening of the proportional valve are adjusted. It can be understood that if the current control mode is pressure control mode, the initial pressurization pressure (TMP) during concentration and filtration at the optimal tangential flow rate (V) and proportional valve opening (K) is read. During the filtration and concentration process, the system pressurization pressure (TMP) is maintained stable at this initial value, and the pressurization pressure (TMP) needs to be within a suitable range of 0-0.1 MPa. A built-in closed-loop feedback control system monitors the pressure (TMP) in real time through the pressure sensor. The controller continuously calculates the error (e=Setpoint-Actual) between the set pressure and the measured value of the pressure sensor, and calculates the control command based on the proportional (P), integral (I), and derivative (D) terms of the error to drive the actuators (pump and proportional valve) to eliminate the error. Pressure stability is maintained by automatically adjusting the flow rate and proportional valve opening. This mode is suitable for water bodies with low algae concentration and low turbidity.

[0059] In this embodiment, if the current control mode is filtration rate control mode, the flow rate of the filtrate is monitored by the flow meter and uploaded to the preset controller. Based on the difference between the filtrate flow rate and the preset flow rate value, the rotational speed of the diaphragm pump and / or the opening of the proportional valve are adjusted. It can be understood that if the current control mode is filtration rate control mode, the initial filtrate flow rate during concentration filtration at the optimal tangential flow rate (V) and proportional valve opening (K) is read. During the filtration concentration process, the flow rate of the filtrate (permeate) is maintained stable at this initial filtrate flow rate, and the pressurization pressure (TMP) needs to be within a suitable range of 0-0.1 MPa. A built-in closed-loop feedback control system monitors the filtrate flow rate in real time through a flow sensor. The controller continuously calculates and compares the measured filtration rate with the set filtration rate to calculate the error. Control commands are calculated based on the proportional (P), integral (I), and derivative (D) terms of the error to drive the actuators (pump and proportional valve) to eliminate the error. Filtration rate stability is maintained by automatically adjusting the flow rate and proportional valve opening. This mode is suitable for water bodies with high algae concentration and turbidity.

[0060] It should be noted that in addition to the two individual control modes mentioned above, a hybrid mode can be selected. That is, the filtration rate control mode is used for rapid concentration in the initial stage of filtration; when the TMP rises to close to the safety threshold (such as 0.09MPa), the system automatically switches to the pressure control mode to complete the subsequent concentration under safe pressure, perfectly balancing efficiency and safety.

[0061] In this embodiment, if the current control mode is the normal control mode, the target tangential flow velocity and target proportional valve opening are determined based on a preset parameter optimization algorithm. This allows the diaphragm pump to pump the water sample to be treated according to the target tangential flow velocity, and the proportional valve to adjust its opening according to the target proportional valve opening. It can be understood that if the current control mode is the normal control mode, the optimal tangential flow velocity (V) determined by the preset parameter optimization algorithm is the target tangential flow velocity, and the proportional valve opening (K) is the target proportional valve opening. During the concentration process, the target tangential flow velocity (V) and target proportional valve opening (K) are maintained constant for water sample concentration and filtration. This mode is suitable for water bodies with moderate algae concentration and turbidity, and relatively stable conditions.

[0062] In this embodiment, the step of determining the target tangential velocity and target proportional valve opening based on a preset parameter optimization algorithm includes: setting the tangential velocity and proportional valve opening as independent variables, and setting filtration time and recovery rate as response variables to establish a quadratic polynomial response surface model; using the expectation function method to perform multi-objective optimization on the quadratic polynomial response surface model to obtain a combination of independent variables that satisfies preset recovery rate constraints and preset filtration time constraints, so as to determine the current tangential velocity and current proportional valve opening in the combination of independent variables as the target tangential velocity and target proportional valve opening, respectively. It is understood that during the filtration process, tangential velocity (V), pressurization pressure (TMP), filtration time (T), and recovery rate (Re) interact and jointly determine the filtration efficiency. Specifically, the pressurization pressure (TMP) is jointly determined by the tangential velocity (V) and the proportional valve opening (K). The tangential flow velocity (V) needs to be maintained within a suitable range. This is necessary to reduce the adsorption effect of plankton and impurities on the membrane surface while ensuring that the plankton morphology is not destroyed by excessive impact force. When the tangential flow velocity (V) is in the range of 0-1.2 L / min, the various plankton morphologies remain intact; exceeding this flow velocity will lead to the destruction of clump-like algae morphology. Depending on the membrane material properties, the pressurization pressure (TMP) needs to be within a suitable range of 0-0.1 MPa. This is necessary to ensure water sample permeability, accelerate filtration efficiency, and also ensure appropriate water sample flow within the membrane tube to reduce adsorption effects. The target concentration factor is 10-20 times, and the recovery rate (Re) needs to reach over 90%.

[0063] Therefore, a quadratic polynomial response surface model is constructed. Specifically, models are established for the two response variables (T, Re) to capture the influence of the independent variables (V, K) and their interaction and nonlinear effects.

[0064] Filtering time (T) model: T = β0 + β1V + β2K + β 12 V*K+β 11 V²+β 22 K²+ε;

[0065] Recovery rate (Re) model: Re = γ0 + γ1V + γ2K + γ 12 V*K+γ 11 V²+γ 22 K²+ε;

[0066] Where β and γ are the model coefficients to be fitted, and ε is the random error term.

[0067] After the model is built, optimization is achieved using a constrained multi-objective expectation function. Specifically, the two variables, tangential velocity (V) and proportional valve opening (K), directly affect the filtration time (T) and recovery rate (Re). The expectation function method is used to optimize the tangential velocity (V) and proportional valve opening (K) to minimize the filtration time (T) and maximize the recovery rate (Re). The core of the algorithm is to transform multiple objective functions and constraints into a single comprehensive index in the range [0, 1], the overall expectation value (D), and then find the solution that maximizes D.

[0068] For the recovery rate (Re), the goal is to maximize it. If Re < 90%, then d(Re) = 0, which completely violates the constraint and is unacceptable. If Re = 100%, then d(Re) = 1, which is the ideal state. When Re is between 90% and 100%, d(Re) increases linearly or non-linearly from 0 to 1.

[0069] For the filtering time (T), the objective is to minimize it and ensure it is ≤30 min. If T>30 min, then d(T)=0, violating the constraint and unacceptable. If T=0 min, then d(T)=1, the ideal state. When T is between 0 and 30 min, d(T) decreases linearly or non-linearly from 1 to 0.

[0070] The overall expected value is D=(d(Re)*d(T)) 1 / 2 The optimization objective is to find the (V, K) combination of operating parameters that maximizes the overall expected value D.

[0071] Specifically, the optimized process and steps are as follows:

[0072] First, define the variables and optimization objectives. The independent variables (X) are V: tangential flow rate, with a range of 0.1 - 1.2 L / min; K: proportional valve opening, with a range of 1 - 100. The dependent variable / response (Y) is T: filtration time (min), with the objective of minimizing it, and Re: recovery rate (%), with the objective of maximizing it. The hard constraint is Re ≥ 90%, and T ≤ 30 min. The process constraint is the transmembrane pressure (TMP, MPa), which must satisfy: 0 < TMP ≤ 0.1 MPa, and it should be monitored in real-time during each experiment to ensure compliance. The experiment uses a central composite design. It sets 5 levels for each factor and can efficiently fit a quadratic model with the least number of experiments. A total of 13 experimental points are required (4 factorial points, 4 axial points, and 5 central points). The factor level coding table is shown in Table 1 below:

[0073] Table 1 Factor Level Coding Table

[0074]

[0075] Conduct experiments according to the 13 sets of (V, K) conditions designed above. The experimental order should be randomized to eliminate systematic errors. Record the total filtration time T (min) required to reach the target concentration multiple (10x or 20x) for each experiment. Calculate the recovery rate Re (%) by measuring the quantity of the target organism before and after concentration. Monitor TMP in real-time during the experiment to ensure it is always ≤ 0.1 MPa. If a certain (V, K) combination causes the TMP to exceed the standard, that point should be immediately abandoned and the reason should be recorded (this indicates that this area is an infeasible region).

[0076] Input the experimental data using professional statistical software (such as Design-Expert, Minitab, JMP), and fit two quadratic polynomial models through least squares regression to obtain all β and γ coefficients.

[0077] Perform an analysis of variance to check whether the significance of the model is < 0.05. Check whether the lack-of-fit term is > 0.05, indicating that the model is complex and effective enough. Check the goodness of fit: R², Adj-R², and Pred-R² should all be greater than 0.9 and close to each other, indicating a high prediction accuracy of the model.

[0078] In the optimization module of the software, strictly set V and K within the preset range. Set Re to Maximize and set Lower Limit = 90. Set T to Minimize and set Upper Limit = 30.

[0079] The software's optimizer will automatically search within the operation space, calculating d(Re), d(T), and the overall expected value D for different (V, K) combinations, ultimately finding the optimal parameter combination that maximizes D. The constraint is TMP(V, K) ≤ 0.1 MPa. The software will output one or more optimal solutions, for example: optimal parameters: V = 1.0 L / min, K = 80. Predicted response: T... predicted =25min, Re predicted =94%, overall expected value: D=0.92. The optimal parameters recommended by the software were repeatedly verified at least three times. The measured T and Re values ​​are close to the predicted values ​​and stably satisfy all constraints. This indicates that the model is reliable and the optimization was successful. If the deviation is large, it is necessary to go back and check the model and experimental operations, or add experimental points near the optimal solution to refit the model.

[0080] In this embodiment, the tangential flow filtration system further includes: an ultrasonic level sensor and a chlorophyll sensor. The chlorophyll sensor is used to monitor the algae concentration in the water sample to be treated in the metering cup, and to send the algae concentration to the preset controller so as to determine the target concentration factor based on the chlorophyll concentration-concentration factor curve. The ultrasonic level sensor is used to monitor the target liquid level in the metering cup, and to send the target liquid level to the preset controller so as to determine the target concentration factor based on the target liquid level.

[0081] Understandably, the chlorophyll concentration in a water sample directly reflects the concentration of phytoplankton. The chlorophyll sensor inside the quantitative measuring vessel measures chlorophyll fluorescence intensity or turbidity within seconds, and the system's built-in preset controller (processor) receives the sensor signal. The processor has a pre-stored chlorophyll concentration-concentration factor curve algorithm, which determines the concentration factor based on the actual chlorophyll fluorescence value of the water body. For example:

[0082] If the chlorophyll fluorescence value is less than or equal to the first preset threshold, the concentration factor is 20.

[0083] If the first preset threshold is less than the chlorophyll fluorescence value and the second preset threshold is less, the concentration factor is 10.

[0084] If the chlorophyll fluorescence value is greater than or equal to the second preset threshold, the concentration factor is 1.

[0085] The first and second preset thresholds are set based on experimental results in real historical scenarios, and the first preset threshold is much smaller than the second preset threshold. The specific threshold values ​​are set according to actual needs and are not specifically limited.

[0086] In this embodiment, Lugo's reagent is added to the concentrated water sample for fixation treatment to obtain a fixed concentrated water sample. The fixed concentrated water sample is stirred using a magnetic stirrer, and then the mixed water sample is transported to the image detection module for the identification and counting of plankton. It is understood that the amount of Lugo's reagent used can be reduced during the fixation process. Photoelectric detection is used to detect whether Lugo's reagent is low, and a metering pump is used for quantitative extraction of Lugo's reagent. A diaphragm pump is used for water sample extraction, and a metering cup is used for quantitative extraction of 1L water sample. The metering cup is equipped with an ultrasonic level sensor, used for quantitative extraction of both the water sample and the concentrated water sample. The concentration of the water sample can be selected according to the concentration of plankton in the water sample, such as 20 times (50ml), 10 times (100ml), or no concentration. The concentration cycle stops when the ultrasonic level sensor detects that the liquid level has reached the set level. After concentration, Lugo's reagent is added to fix the plankton. A magnetic stirrer is installed at the bottom of the quantitative cup to mix the water sample with Lugo's reagent, so that the plankton in the water sample are evenly distributed for easy detection.

[0087] In this embodiment, a single test uses pure water cleaning. When the number of tests reaches 3 sets or the pretreatment time exceeds 30 minutes, the acid, alkali, and sodium hypochlorite cleaning process is initiated after the pure water cleaning is completed. For different water qualities, to achieve the best cleaning effect, the filter can be cleaned sequentially or in combination with acid, alkali, sodium hypochlorite, and pure water. Filter maintenance only requires replacing the filter tube, which uses a quick-connect design, making filter tube replacement simple.

[0088] In this way, a flow meter is installed at the filtrate outlet to measure the filtrate flow rate. A pressure sensor is used to monitor the pressure inside the tube. Pressurization is achieved through a proportional valve, causing some water to permeate through the membrane tube and be discharged from the filtrate outlet. The planktonic sample is retained inside the membrane tube to achieve concentration. The flow of water inside the membrane tube reduces the adsorption of planktonic organisms on the membrane surface, improves the recovery rate, and increases the permeate flow rate. Concentration is achieved through multiple cycles of filtration. Tangential flow filtration is used to circulate and concentrate phytoplankton and zooplankton in the water sample. The water sample does not require 24-hour sedimentation and concentration. The water sample pretreatment time is about 20 minutes, which greatly shortens the entire detection process time to ≤60 minutes.

[0089] As can be seen, this application discloses a method for issuing a rotation speed command to the diaphragm pump in the tangential flow filtration system based on the current control mode, thereby controlling the diaphragm pump to adjust its current rotation speed so that the water sample to be treated is pumped into the spiral filter in the tangential flow filtration system based on the current rotation speed; and sending a proportional valve opening adjustment command to the proportional valve in the tangential flow filtration system based on the received tangential flow velocity and transmembrane pressure, so as to adjust the opening of the proportional valve based on the proportional valve opening adjustment command, thereby controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system, and controlling the tangential flow velocity and / or transmembrane pressure of the water sample to be treated, concentrating the plankton in the water sample to the target volume within a preset time, and controlling the recovery rate of the plankton in the water sample to reach a preset recovery rate threshold. Therefore, it is evident that the active, externally applied dynamic filtration method of tangential flow circulation filtration pumps the water sample into the system and causes it to flow at high speed within the membrane tube. Water molecules and small molecules permeate through the membrane wall under pressure (filtrate), while plankton are trapped and continue to circulate with the main liquid flow, thus achieving rapid concentration and directly reducing pretreatment time from days to minutes. Furthermore, during the tangential flow circulation filtration process, by controlling and maintaining a suitable tangential flow rate, a sweeping effect is generated, effectively flushing the membrane surface and reducing the adsorption of plankton and concentration polarization on the membrane surface, achieving a high recovery rate. By controlling the transmembrane pressure and keeping it within a safe range, excessive pressure is avoided from squeezing and destroying plankton on the membrane wall, or damaging the morphology of fragile species due to excessive shear force. In this way, both high recovery rate and biological morphological integrity are achieved simultaneously, providing a high-quality, non-destructive sample basis for subsequent automated identification based on image recognition, ensuring the accuracy and reliability of monitoring data.

[0090] like Figure 2 As shown, the present invention provides a tangential flow filtration system, comprising: a diaphragm pump, a spiral filter, a metering cup, a flow meter, a preset controller, a pressure sensor, and a proportional valve, wherein...

[0091] The inlet of the diaphragm pump is connected to the metering cup via a pipeline, the outlet of the diaphragm pump is connected to the inlet of the spiral filter, and the outlet of the spiral filter returns to the metering cup via a pipeline, forming a circulating concentration loop. The filtrate outlet of the spiral filter is connected to the flow meter, and the preset controller is electrically connected to the pressure sensor, the flow meter, the diaphragm pump, and the proportional valve, respectively.

[0092] The preset controller is used to issue a speed command to the diaphragm pump based on the current control mode to control the current speed of the diaphragm pump;

[0093] The diaphragm pump is used to pump the water sample to be treated in the metering cup into the spiral filter based on the current rotation speed;

[0094] The preset controller is used to receive the tangential flow velocity and transmembrane pressure sent by the flow meter and the pressure sensor installed on the pipeline of the circulation loop, respectively, so as to send a proportional valve opening adjustment command to the proportional valve based on the current control mode.

[0095] The proportional valve installed in the pipeline of the circulating concentration loop is used to receive the proportional valve opening adjustment command from the preset controller and adjust the proportional valve opening.

[0096] The preset controller is used to concentrate the water sample to be treated in the metering cup to a target volume within a preset time by controlling the tangential flow rate and / or the transmembrane pressure, and to control the recovery rate of plankton in the water sample to reach a preset recovery rate threshold.

[0097] The tangential flow filtration system further includes: an ultrasonic level sensor and a chlorophyll sensor. The chlorophyll sensor is used to monitor the algae concentration in the water sample to be treated in the metering cup, and to send the algae concentration to the preset controller so as to determine the target concentration factor based on the chlorophyll concentration-concentration factor curve. The ultrasonic level sensor is used to monitor the target liquid level in the metering cup, and to send the target liquid level to the preset controller so as to determine the target concentration factor based on the target liquid level.

[0098] Understandably, the spiral filter is the core separation element of this system. Its specific configuration is as follows: a filter membrane tube with a pore size of 0.3-3μm and a tube diameter of 3-7mm is spirally wound and fixed to a membrane tube fixing column. This filter has one inlet, one outlet, one filtrate outlet, and one vent. This spiral design increases the filtration area and promotes fluid turbulence, reducing clogging. The circulating concentration loop: a metering cup is used to hold and measure the water sample to be treated (typically 1L) and is equipped with an ultrasonic level sensor for accurate monitoring of the concentration volume. In addition, the metering cup is also equipped with a chlorophyll sensor to monitor the algae concentration in the water sample. The inlet of the diaphragm pump is connected to the metering cup via a pipeline, and its outlet is connected to the inlet of the spiral filter. The outlet of the filter returns to the metering cup via a pipeline. Thus, the metering cup, diaphragm pump, spiral filter inlet, spiral filter outlet, and metering cup form a complete circulating concentration loop. A pressure sensor is directly installed on the pipeline of the circulating concentration loop to monitor the pressure within the system in real time, which directly characterizes the critical transmembrane pressure (TMP). A flow meter is installed on the filtrate outlet pipeline of the spiral filter to accurately measure the instantaneous flow rate of the filtrate. A proportional valve is installed on the pipeline of the circulating concentration loop (usually located after the outlet) as an adjustable resistance component to receive electrical signals and precisely adjust its opening. A preset controller (whose physical carrier can be a PLC, embedded motherboard, etc.) acts as the brain of the system, electrically connected to the pressure sensor, flow meter, diaphragm pump, and proportional valve via cables, forming a complete automated control system for data acquisition and command issuance.

[0099] Based on the selected control mode, the preset controller sends a speed command to the diaphragm pump. The diaphragm pump operates at this speed, pumping the water sample to be treated from the metering cup into the inlet of the spiral filter. The water sample undergoes tangential flow filtration within the filter, and the concentrate flows back to the metering cup from the outlet, instantly establishing a circulating concentration loop. The controller selects and executes different control modes based on water sample characteristics (such as algae concentration and turbidity). The decision-making and execution process is as follows: Normal mode: The controller calls the target tangential flow velocity (V) and target proportional valve opening (K) determined by optimization algorithms (such as quadratic polynomial response surface model and expectation function method), and controls the diaphragm pump and proportional valve to operate at these parameters. This mode is suitable for stable water quality conditions. Pressure control mode: The controller continuously reads the transmembrane pressure (TMP) signal from the pressure sensor and compares it with the preset initial pressure value. Through the built-in PID control algorithm, it dynamically calculates and sends commands to the diaphragm pump (adjusting the speed) and proportional valve (adjusting the opening) to stabilize TMP at the set value while ensuring that TMP is always within the safe range of 0-0.1 MPa. This mode is suitable for low-turbidity water. Filtration rate control mode: The controller continuously reads the filtrate flow rate signal from the flow meter and compares it with the preset initial filtration rate. Similarly, using a PID algorithm, it dynamically adjusts the diaphragm pump and proportional valve to maintain a stable filtration rate while monitoring TMP to ensure it does not exceed limits. This mode is suitable for high-turbidity water and ensures stable concentration efficiency. Mixing mode: The controller can intelligently switch modes. For example, it initially uses the filtration rate control mode for rapid concentration. When the pressure sensor detects that TMP has risen to approximately 0.09 MPa, it automatically switches to the pressure control mode to complete concentration while ensuring the safety of the membrane tubing. Throughout the process, the core objective of the preset controller is to concentrate the water sample in the metering cup to the target volume (50 ml or 100 ml) within a preset time (e.g., ≤30 minutes) through precise control of the tangential flow rate and / or transmembrane pressure, while ensuring that the plankton recovery rate reaches a preset threshold (above 90%). The ultrasonic level sensor in the metering cup provides real-time volume information to the controller, serving as a trigger signal for concentration termination. Similarly, the chlorophyll sensor in the metering cup provides real-time chlorophyll concentration information, allowing the controller to determine the recovery rate of algae in the concentrated water sample. After concentration, the system drives a metering pump to add Lugol reagent to the metering cup for fixation, followed by mixing with a magnetic stirrer. Furthermore, the preset controller manages the cleaning process, sequentially driving a diaphragm pump to extract pure water, acid, alkali, sodium hypochlorite, and other cleaning agents for automatic cleaning and maintenance of the spiral filter and the entire pipeline.

[0100] Therefore, the tangential flow filtration system, through specific connections of hardware such as a spiral filter, diaphragm pump, proportional valve, pressure sensor, flow meter, and metering cup, and with a preset controller acting as the central nervous system to implement multi-mode intelligent control, constitutes a technical solution capable of rapid, efficient, and fully automated concentration of planktonic organisms in water samples. This filtration and concentration equipment features a modular design, suitable for both rapid concentration of laboratory samples and pretreatment of water samples in online systems.

[0101] like Figure 3 As shown, this invention discloses an online pretreatment method for plankton. The concentration mode is set to normal. Diaphragm pump 1 draws 1L of water sample into a metering cup, and diaphragm pump 2 draws the water sample into a filter for filtration and concentration. A pressure sensor detects the pressure within the pipeline. Water permeating through the membrane fibers is discharged through the drain port. After concentration, the water sample enters the metering cup and is drawn back into the filter by diaphragm pump 2 for continuous concentration until the water sample volume in the cup reaches the target volume. Concentration is then stopped. Metering pump 3 draws 0.5-1ml of Lugo reagent into the metering cup to fix the water sample and starts stirring to homogenize the sample for 5-10 minutes. Metering pump 4 draws the fixed water sample into the counting window, where the objective lens focuses and takes images. Simultaneously, a counting model is identified for image recognition and counting, outputting a phytoplankton and zooplankton detection report. After the test, excess water in the metering cup is discharged through the drain port, and diaphragm pump 1 draws pure water to clean the metering cup. The proportional valve is depressurized, and diaphragm pump 2 draws pure water to clean the filter circulation pipeline. Waste liquid is discharged from the metering cup drain port. When the three-way valve is closed, diaphragm pump 2 sequentially draws pure water, acid and alkali, and sodium hypochlorite to clean the filter, and discharges it from the cleaning waste outlet.

[0102] like Figure 4 As shown, the present invention also provides a device for concentrating plankton in a water sample, which is applied to a preset controller in a tangential flow filtration system, comprising:

[0103] The water sample pumping module 11 is used to send a speed command to the diaphragm pump in the tangential flow filtration system based on the current control mode to control the diaphragm pump to adjust the current speed so that the water sample to be treated is pumped into the spiral filter in the tangential flow filtration system based on the current speed.

[0104] The concentration module 12 is used to send a proportional valve opening adjustment command to the proportional valve in the tangential flow filtration system based on the received tangential flow velocity and transmembrane pressure, so as to adjust the opening of the proportional valve based on the proportional valve opening adjustment command, thereby controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system, and controlling the tangential flow velocity and / or transmembrane pressure of the water sample to be treated, concentrating the plankton in the water sample to the target volume within a preset time, and controlling the recovery rate of the plankton in the water sample to reach a preset recovery rate threshold.

[0105] Therefore, it is evident that the fully automated process completes a series of steps including phytoplankton sampling, fixation and concentration, and automatic sample introduction, without the need for manual supervision. It can quickly filter and concentrate phytoplankton and zooplankton, and achieve high-frequency, long-term online monitoring. After being put into practical application, it can significantly save manpower and resources, thereby improving the efficiency of phytoplankton monitoring in water.

[0106] Furthermore, embodiments of this application also disclose an electronic device, Figure 5 This is a structural diagram of an electronic device 20 according to an exemplary embodiment. The content of the diagram should not be construed as limiting the scope of this application.

[0107] Figure 5 This is a schematic diagram of the structure of an electronic device 20 provided in an embodiment of this application. Specifically, the electronic device 20 may include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. The memory 22 stores a computer program, which is loaded and executed by the processor 21 to implement the relevant steps in the method for concentrating plankton in water samples disclosed in any of the foregoing embodiments. Alternatively, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0108] In this embodiment, the power supply 23 is used to provide operating voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol it follows can be any communication protocol applicable to the technical solution of this application, and is not specifically limited here; the input / output interface 25 is used to acquire external input data or output data to the outside world, and its specific interface type can be selected according to specific application needs, and is not specifically limited here.

[0109] The processor 21 may include one or more processing cores, such as a quad-core processor or an octa-core processor. The processor 21 may be implemented using at least one hardware form selected from DSP (Digital Signal Processing), FPGA (Field-Programmable Gate Array), and PLA (Programmable Logic Array). The processor 21 may also include a main processor and a coprocessor. The main processor, also known as a CPU (Central Processing Unit), is used to process data in the wake-up state; the coprocessor is a low-power processor used to process data in the standby state. In some embodiments, the processor 21 may integrate a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content to be displayed on the screen. In some embodiments, the processor 21 may also include an AI (Artificial Intelligence) processor, which is used to handle computational operations related to machine learning.

[0110] In addition, the memory 22, as a carrier for resource storage, can be a read-only memory, random access memory, disk or optical disk, etc. The resources stored thereon can include operating system 221, computer program 222, etc., and the storage method can be temporary storage or permanent storage.

[0111] The operating system 221 manages and controls the various hardware devices and computer programs 222 on the electronic device 20 to enable the processor 21 to perform calculations and processing on the massive amounts of data 223 in the memory 22. It can be Windows Server, Netware, Unix, Linux, etc. The computer program 222, in addition to including a computer program capable of performing the method for concentrating plankton in a water sample as disclosed in any of the foregoing embodiments, may further include computer programs capable of performing other specific tasks. The data 223 may include data received by the electronic device from external devices, as well as data collected by its own input / output interface 25.

[0112] Furthermore, this application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the aforementioned method for concentrating plankton in water samples. Specific steps of this method can be found in the corresponding content disclosed in the foregoing embodiments, and will not be repeated here.

[0113] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section.

[0114] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application. The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein can be implemented directly in hardware, software modules executed by a processor, or a combination of both. The software module may be located in random access memory (RAM), memory, read-only memory (ROM), electrically programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, removable disks, CD-ROMs (Compact Disc-Read Only Memory), or any other form of storage medium known in the art.

[0115] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0116] The solution provided by the present invention has been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for concentrating plankton in a water sample, characterized in that, A preset controller used in a tangential flow filtration system includes: Based on the current control mode, a speed command is sent to the diaphragm pump in the tangential flow filtration system to control the diaphragm pump to adjust the current speed so that the water sample to be treated is pumped into the spiral filter in the tangential flow filtration system based on the current speed. Based on the received tangential flow velocity and transmembrane pressure, a proportional valve opening adjustment command is sent to the proportional valve in the tangential flow filtration system. The opening of the proportional valve is adjusted according to the proportional valve opening adjustment command to control the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system. The tangential flow velocity and / or transmembrane pressure of the water sample to be treated are controlled to concentrate the water sample to be treated to a target volume within a preset time. The recovery rate of plankton in the water sample to be treated is controlled to reach a preset recovery rate threshold.

2. The method for concentrating plankton in a water sample according to claim 1, characterized in that, The spiral filter is constructed by spirally winding and fixing filter membrane tubes with a pore size range of 0.3 to 3 μm and a tube diameter of 3 to 7 mm onto a membrane tube fixing post.

3. The method for concentrating plankton in a water sample according to claim 2, characterized in that, The spiral filter is provided with an inlet, an outlet, a filtrate outlet, and an exhaust port; Accordingly, controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system includes: Air is expelled from the spiral filter through the vent, the water sample to be treated is pumped into the spiral filter from the inlet, the water sample to be treated is controlled to undergo tangential flow filtration in the tangential flow filtration system, the concentrated water sample flows out from the outlet and returns for circulation, and then the filtrate is discharged from the filtrate outlet.

4. The method for concentrating plankton in a water sample according to claim 1, characterized in that, The tangential flow filtration system also includes a pressure sensor and a flow meter; Accordingly, controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system, and controlling the tangential flow velocity and / or transmembrane pressure of the water sample to be treated, includes: If the current control mode is pressure control mode, the transmembrane pressure is monitored by the pressure sensor and uploaded to the preset controller. Based on the difference between the transmembrane pressure and the preset pressure value, the speed of the diaphragm pump and / or the opening of the proportional valve are adjusted. If the current control mode is the filtration rate control mode, the flow rate of the filtrate is monitored by the flow meter and the flow rate of the filtrate is uploaded to the preset controller. Based on the difference between the filtrate flow rate and the preset flow rate value, the speed of the diaphragm pump and / or the opening of the proportional valve are adjusted. If the current control mode is normal control mode, the target tangential flow velocity and target proportional valve opening are determined based on the preset parameter optimization algorithm, so as to control the diaphragm pump to pump the water sample to be treated according to the target tangential flow velocity, and control the proportional valve to adjust the opening according to the target proportional valve opening.

5. The method for concentrating plankton in a water sample according to claim 4, characterized in that, The method for determining the target tangential flow velocity and the target proportional valve opening based on the preset parameter optimization algorithm includes: By setting tangential flow velocity and proportional valve opening as independent variables, and filtration time and recovery rate as response variables, a quadratic polynomial response surface model is established. The quadratic polynomial response surface model is optimized using the expectation function method to obtain a combination of independent variables that satisfies the preset recovery rate constraint and the preset filtration time constraint. The current tangential velocity and the current proportional valve opening in the combination of independent variables are then determined as the target tangential velocity and the target proportional valve opening, respectively.

6. The method for concentrating plankton in a water sample according to claim 1, characterized in that, Also includes: Lugo's reagent was added to the concentrated water sample for fixation treatment to obtain a fixed concentrated water sample; The concentrated water sample after fixation is stirred by a magnetic stirrer, and then the mixed water sample is sent to the image detection module for the identification and counting of plankton.

7. A tangential flow filtration system, characterized in that, include: Diaphragm pump, spiral filter, metering cup, flow meter, preset controller, pressure sensor, proportional valve, among which, The inlet of the diaphragm pump is connected to the metering cup via a pipeline, the outlet of the diaphragm pump is connected to the inlet of the spiral filter, and the outlet of the spiral filter returns to the metering cup via a pipeline, forming a circulating concentration loop. The filtrate outlet of the spiral filter is connected to the flow meter, and the preset controller is electrically connected to the pressure sensor, the flow meter, the diaphragm pump, and the proportional valve, respectively. The preset controller is used to issue a speed command to the diaphragm pump based on the current control mode to control the current speed of the diaphragm pump; The diaphragm pump is used to pump the water sample to be treated in the metering cup into the spiral filter based on the current rotation speed; The preset controller is used to receive the tangential flow velocity and transmembrane pressure sent by the flow meter and the pressure sensor installed on the pipeline of the circulation loop, respectively, so as to send a proportional valve opening adjustment command to the proportional valve based on the current control mode. The proportional valve installed in the pipeline of the circulating concentration loop is used to receive the proportional valve opening adjustment command from the preset controller and adjust the proportional valve opening. The preset controller is used to concentrate the plankton in the water sample to be treated in the metering cup to a target volume within a preset time by controlling the tangential flow rate and / or the transmembrane pressure, and to control the recovery rate of the plankton in the water sample to be treated to reach a preset recovery rate threshold.

8. The tangential flow filtration system according to claim 7, further comprising: Ultrasonic liquid level sensor, chlorophyll sensor, among which... The chlorophyll sensor is used to monitor the algae concentration in the water sample to be treated in the metering cup, and send the algae concentration to the preset controller so as to determine the target concentration factor based on the chlorophyll concentration-concentration factor curve; The ultrasonic liquid level sensor is used to monitor the target liquid level in the metering cup and send the target liquid level to the preset controller so as to determine the target concentration factor based on the target liquid level.

9. A device for concentrating plankton in a water sample, characterized in that, A preset controller used in a tangential flow filtration system includes: The water sample pumping module is used to send a speed command to the diaphragm pump in the tangential flow filtration system based on the current control mode to control the diaphragm pump to adjust the current speed so that the water sample to be treated is pumped into the spiral filter of the tangential flow filtration system based on the current speed. The concentration module is used to send a proportional valve opening adjustment command to the proportional valve in the tangential flow filtration system based on the received tangential flow velocity and transmembrane pressure, so as to adjust the opening of the proportional valve based on the proportional valve opening adjustment command, thereby controlling the water sample to be treated to undergo tangential flow circulation filtration in the tangential flow filtration system, and controlling the tangential flow velocity and / or transmembrane pressure of the water sample to be treated, concentrating the water sample to be treated to a target volume within a preset time, and controlling the recovery rate of plankton in the water sample to reach a preset recovery rate threshold.

10. An electronic device, characterized in that, include: Memory, used to store computer programs; A processor for executing the computer program to implement the steps of the method for concentrating plankton in a water sample as described in any one of claims 1 to 7.

11. A computer-readable storage medium, characterized in that, Used to store a computer program; wherein, when the computer program is executed by a processor, it implements the steps of the method for concentrating plankton in a water sample as described in any one of claims 1 to 7.

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