One-to-one pressure dosing method and system for sewage treatment

Abstract

The application relates to the technical field of sewage treatment, in particular to a one-to-one pressure dosing method and system for sewage treatment. According to the Bernoulli equation principle in fluid mechanics, it is found that the pressure value is in direct proportion to the square of the flow value, and under a certain working condition, a pressure-flow corresponding relation formula is first established, after the target dosing flow value is obtained, the target dosing flow value is substituted into the preset pressure-flow corresponding relation formula, the pressure value required by the dosing tank is calculated, and then the actual flow value is obtained by using the liquid level change value; the actual flow value is compared and calibrated with the target dosing flow value; the damage of the flow meter in the traditional flow meter is avoided; stable and reliable pressure sensors and liquid level sensors are adopted; accurate metering is realized through an intelligent algorithm; the cost is lower and the reliability is higher.

Description

Technical Field

[0001] This application relates to the technical field of wastewater treatment, and in particular to a one-to-one pressure dosing method and system for wastewater treatment. Background Technology

[0002] Wastewater treatment is an important area of ​​environmental protection, and currently, my country mainly uses wastewater treatment plants for centralized treatment. Various chemicals need to be added during the wastewater treatment process, including acid-base chemicals, redox chemicals, and flocculants in the physicochemical treatment unit, as well as carbon source replenishment and alkalinity replenishment in the biochemical treatment unit. The types and dosages of chemicals required vary depending on the type of wastewater.

[0003] Currently, electromagnetic flowmeters or rotor flowmeters are commonly used in conjunction with dosing pumps for controlling the addition of chemicals in wastewater treatment. However, the diverse properties of chemicals, such as the viscosity of PAM, the tendency of lime slurry to form scale, and the corrosiveness of acids and alkalis, significantly impact the accuracy and lifespan of metering equipment.

[0004] Existing flow meters are susceptible to corrosion and scaling caused by chemicals during use, which leads to a gradual decrease in measurement accuracy. Some chemicals can stain or clog the flow meters, causing them to lose their measurement function. In addition, flow meter malfunctions often can only be addressed after the abnormality is detected, lacking real-time monitoring and automatic calibration capabilities. These issues need further improvement. Summary of the Invention

[0005] To address the problems of existing flow meters being susceptible to corrosion and scaling by chemicals during use, leading to a gradual decrease in metering accuracy, and the fact that flow meter malfunctions often require waiting until an anomaly is detected before they can be addressed, lacking real-time monitoring and automatic calibration capabilities, this application provides a one-to-one pressure dosing method and system for wastewater treatment, employing the following technical solution:

[0006] In a first aspect, this application provides a one-to-one pressure dosing method for wastewater treatment, characterized by comprising the following steps:

[0007] Obtain the target dosing flow rate value, substitute the target dosing flow rate value into the preset pressure-flow rate correspondence formula, and calculate the pressure value required by the dosing tank. In the pressure-flow rate correspondence formula, the pressure value is proportional to the square of the flow rate value.

[0008] The measured flow rate is obtained by measuring the change in liquid level using a liquid level sensor.

[0009] By comparing the target dosing flow rate with the measured flow rate, the flow error rate is determined.

[0010] When the flow error rate exceeds the preset range, the pressure value of the dosing tank is adjusted for calibration until the flow error rate is within the preset range.

[0011] By adopting the above technical solution, this application addresses the problem of corrosion and scaling of metering equipment in wastewater treatment dosing systems. For example, when adding lime slurry, even with corrosion-resistant electromagnetic flowmeters, scaling still occurs after a period of use, leading to decreased metering accuracy and high replacement and maintenance costs. Furthermore, when adding sodium sulfide, the rotor flowmeter becomes blackened and unreadable. This application utilizes Bernoulli's equation in fluid mechanics, finding a direct proportional relationship between pressure and the square of the flow rate. It first obtains the target dosing flow rate, substitutes it into a preset pressure-flow rate correspondence formula to calculate the required pressure in the dosing tank, and then uses the liquid level change to obtain the actual flow rate. The actual flow rate is then compared and calibrated with the target dosing flow rate. This avoids the drawbacks of traditional flowmeters being easily damaged, employs stable and reliable pressure and level sensors, and achieves accurate metering through intelligent algorithms, resulting in lower costs and higher reliability.

[0012] Optionally, the pressure-flow correspondence is obtained through calibration, specifically including the following steps:

[0013] Multiple pressure values ​​are selected, and the pressure values ​​are set from low to high within the allowable working pressure range;

[0014] The actual average flow rate corresponding to each of the above pressure values ​​is calculated by the change in liquid level in the dosing tank within a preset time period.

[0015] Multiple set pressure values ​​are fitted to the corresponding measured average flow rate values ​​using the relationship P=MQ²+N to determine the values ​​of fitting coefficients M and N, where P is the pressure value of the dosing tank and Q is the dosing flow rate value.

[0016] Determine whether the fitting correlation coefficient exceeds the correlation coefficient of the preset fitting formula. When the fitting correlation coefficient exceeds the correlation coefficient of the preset fitting formula, complete the calibration of the pressure-flow correspondence formula.

[0017] Traditional methods are only applicable to one operating condition. When the type of reagent changes, or when the flow meter or pipeline becomes scaled, the measurement accuracy will be greatly reduced. For example, when adding lime at a wastewater treatment plant, the flow rate deviation can reach more than 30% due to the strong scaling properties of the reagent. This application first selects multiple pressure values ​​within the working pressure range, and obtains the actual flow rate by accurately measuring the liquid level change at each pressure value. Then, it uses the mathematical model P=MQ²+N to fit the data and introduces the fitting correlation coefficient as the criterion for determining the calibration quality. Through mathematical modeling and statistical methods, a universal pressure-flow relationship is established, which not only improves the dosing accuracy but also adapts to changes in operating conditions under different viscosity and temperature conditions.

[0018] Optionally, the pressure-flow correspondence is obtained through calibration, and further includes the following steps:

[0019] Use liquid level monitoring to determine if the dosing tank has reached a low liquid level;

[0020] When the dosing tank reaches a low liquid level, close the dosing valve, pause calibration, and open the inlet valve to add chemicals to a high liquid level.

[0021] After adding the drug to the high liquid level, close the inlet valve and continue the calibration process;

[0022] If the correlation coefficient of the fitting does not exceed the correlation coefficient of the preset fitting formula, the calibration step is re-executed.

[0023] By adopting the above technical solution, the continuity and accuracy of the calibration process are ensured. This improves upon the problem that traditional calibration methods often require manual judgment and replenishment when the liquid solution is insufficient, which can easily lead to calibration interruptions or data inconsistencies. The system in this application continuously monitors liquid level changes. When the liquid level drops to a preset low value, it automatically closes the dosing valve and opens the inlet valve to replenish the liquid. Once the liquid level recovers, the calibration process can be seamlessly resumed. At the same time, the fitting correlation coefficient is introduced as an evaluation index for calibration quality to ensure a high-precision pressure-flow correspondence. This not only avoids errors and interruptions caused by manual intervention, but also achieves high efficiency, accuracy, and reliability in the calibration process through intelligent control and data quality assessment.

[0024] Optionally, when the flow error rate exceeds a preset range, the pressure value of the dosing tank is adjusted for calibration, specifically including the following steps:

[0025] When the absolute value of the flow error rate exceeds the first preset threshold but is less than the second preset threshold, the output pressure value is automatically adjusted according to the current output pressure and the flow error rate.

[0026] The pressure is output according to the adjusted pressure value through a proportional valve;

[0027] Automatic calibration stops when the absolute value of the calibrated flow error rate is less than the first preset threshold.

[0028] If the absolute value of the flow error rate cannot be reduced to less than the first preset threshold after exceeding the preset calibration number, and the tank pressure exceeds the preset safe working pressure value, automatic calibration will stop and an alarm will be triggered to prompt recalibration.

[0029] By adopting the above technical solution, in order to solve the problem of automatic correction of flow deviation during the operation of the dosing system, traditional methods often use simple proportional adjustment or fixed step size adjustment, which lacks a refined control strategy. This application first determines whether the flow error rate falls within the preset range. When the error exceeds the limit, the optimal pressure value is automatically calculated based on the current pressure and the error rate, and executed precisely through a proportional valve. At the same time, an upper limit for the number of calibrations and pressure over-limit protection are set. If the system cannot be restored to normal through automatic calibration, an alarm is promptly triggered to prompt recalibration. This not only achieves automatic maintenance of dosing accuracy, but also avoids the waste of reagents caused by calibration failure by introducing a safety protection mechanism, reflecting the unity of intelligence and safety.

[0030] Optionally, the output pressure value can be automatically adjusted based on the current output pressure and flow error rate, specifically including the following steps:

[0031] When the flow error rate is negative, the adjusted pressure value is equal to the current pressure value multiplied by (1 + the absolute value of the flow error rate).

[0032] When the flow error rate is positive, the adjusted pressure value is equal to the current pressure value multiplied by (1 - the absolute value of the flow error rate);

[0033] The current pressure value is the pressure value obtained from the previous calibration. If it is the first calibration, the current pressure value is the pressure value calculated according to the pressure-flow correspondence formula.

[0034] By adopting the above technical solution, in order to accurately calculate the pressure calibration value, traditional methods often use fixed step size or simple proportional adjustment, which is difficult to adapt to the adjustment needs under different error levels. The present application system judges the positive and negative directions of the flow error. When the actual flow is less than the target value, the pressure value is increased proportionally to the error; when the actual flow is greater than the target value, the pressure value is decreased proportionally to the error. At the same time, by introducing historical pressure values ​​as a benchmark, the continuity and stability of the adjustment are ensured. Adaptive optimization of the adjustment step size is achieved, and the accuracy and efficiency of the adjustment are improved by differentiating between positive and negative errors.

[0035] Optionally, the method further includes the following steps:

[0036] When the flow error rate becomes negative and exceeds the first preset threshold after multiple consecutive calibrations, it is determined to be a risk of drug discharge pipe blockage, triggering a drug discharge pipe blockage alarm and prompting recalibration.

[0037] When the flow error rate is positive after multiple consecutive calibrations and exceeds the first preset threshold, it is determined that there is a risk of proportional valve failure or leakage in the dosing pipe, triggering a corresponding alarm and prompting for maintenance and troubleshooting.

[0038] By adopting the above technical solution, in order to promptly detect equipment failures and safety hazards in the dosing system, traditional methods mainly rely on manual inspection and experience-based judgment, which are difficult to achieve early warning. For example, during the flocculant dosing process, a wastewater treatment plant failed to detect the risk of blockage caused by pipe scaling in time, ultimately resulting in complete blockage of the dosing pipeline, forcing a shutdown for cleaning and affecting the continuity of the process. The system of this application continuously monitors the changing trend of the flow error rate. When a continuous negative error is detected, it is determined that there may be a risk of blockage in the discharge pipeline. When a continuous positive error occurs, it is determined that there is a risk of proportional valve failure or pipeline leakage, and differentiated alarms and handling suggestions are issued for different types of fault risks. This not only achieves early warning of equipment failure, but also provides a preliminary diagnosis of the cause of the failure through intelligent analysis.

[0039] Secondly, this application provides a one-to-one pressure dosing system for wastewater treatment, comprising:

[0040] Dosing tank, pressure sensor, level sensor, proportional valve and controller;

[0041] The pressure sensor is used to measure the current pressure value of the dosing tank;

[0042] The liquid level sensor is used to measure the change in liquid level in the dosing tank.

[0043] The proportional valve is used to adjust the pressure value of the dosing tank;

[0044] The controller is electrically connected to the pressure sensor, the liquid level sensor and the proportional valve respectively, and is used to execute the above-described one-to-one pressure dosing method for wastewater treatment.

[0045] Optionally, the system may also include:

[0046] The inlet valve is used to replenish the drug solution in the dosing tank;

[0047] Dosing valve, used to control the output of liquid medicine;

[0048] The controller is also electrically connected to the inlet valve and the dosing valve to control the inlet and dosing process based on the measured values ​​of the liquid level sensor.

[0049] Thirdly, this application provides a dosing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the one-to-one pressure dosing method for wastewater treatment described above.

[0050] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described one-to-one pressure dosing method for wastewater treatment.

[0051] In summary, this application includes at least one of the following beneficial technical effects:

[0052] 1. This application utilizes the Bernoulli equation principle in fluid mechanics, discovering a direct proportional relationship between pressure and the square of flow rate. Under a certain working condition, a pressure-flow rate correspondence is first established. After obtaining the target dosing flow rate, the target dosing flow rate is substituted into the preset pressure-flow rate correspondence to calculate the required pressure value of the dosing tank. Then, the actual flow rate is obtained using the liquid level change value. The actual flow rate is compared and calibrated with the target dosing flow rate value. This avoids the disadvantages of traditional flow meters being easily damaged. It adopts stable and reliable pressure and liquid level sensors, and achieves accurate measurement through intelligent algorithms, resulting in lower cost and higher reliability.

[0053] 2. Traditional methods are only applicable to one operating condition. When the type of reagent changes, or when the flow meter or pipeline becomes scaled, the measurement accuracy will be greatly reduced. For example, when adding lime at a wastewater treatment plant, the flow rate deviation can reach more than 30% due to the strong scaling properties of the reagent. This application first selects multiple pressure values ​​within the working pressure range, and obtains the actual flow rate by accurately measuring the liquid level change at each pressure value. Then, it uses the mathematical model P=MQ²+N to fit the data and introduces the fitting correlation coefficient as the basis for judging the calibration quality. Through mathematical modeling and statistical methods, a universal pressure-flow relationship is established, which not only improves the dosing accuracy but also can adapt to changes in operating conditions under different viscosity and temperature conditions.

[0054] 3. This system ensures the continuity and accuracy of the calibration process, improving upon traditional calibration methods that often require manual judgment and replenishment when the drug solution is insufficient, which can easily lead to calibration interruptions or data inconsistencies. The system continuously monitors liquid level changes; when the liquid level drops to a preset low value, it automatically closes the dosing valve and opens the inlet valve to replenish the solution. Once the liquid level recovers, the calibration process continues seamlessly. Furthermore, a fitting correlation coefficient is introduced as an evaluation index for calibration quality, ensuring a high-precision pressure-flow correspondence. This not only avoids errors and interruptions caused by manual intervention but also achieves high efficiency, accuracy, and reliability in the calibration process through intelligent control and data quality assessment. Attached Figure Description

[0055] Figure 1 This is a schematic flowchart of a one-to-one pressure dosing method for wastewater treatment according to an embodiment of this application;

[0056] Figure 2 This is a schematic diagram of the dosing system according to an embodiment of this application;

[0057] Figure 3 This is a schematic flowchart of step S110 in a one-to-one pressure dosing method for wastewater treatment according to an embodiment of this application;

[0058] Figure 4 This is a schematic diagram of data fitting in an embodiment of this application;

[0059] Figure 5 This is a schematic diagram of the process for calibrating the pressure-flow correspondence formula in an embodiment of this application;

[0060] Figure 6 This is a schematic flowchart of step S140 in a one-to-one pressure dosing method for wastewater treatment according to an embodiment of this application;

[0061] Figure 7 This is a schematic flowchart of step S141 in a one-to-one pressure dosing method for wastewater treatment according to an embodiment of this application;

[0062] Figure 8 This is a schematic flowchart of a fault analysis process in a one-to-one pressure dosing method for wastewater treatment according to an embodiment of this application;

[0063] Figure 9 This is a schematic diagram of a one-to-one pressure dosing system for wastewater treatment according to an embodiment of this application;

[0064] Figure 10 This is an internal structural diagram of a dosing device according to an embodiment of this application. Detailed Implementation

[0065] The terminology used in the following embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to include the plural expressions as well, unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this application refers to any or all possible combinations including one or more of the listed items.

[0066] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature, and in the description of the embodiments of this application, unless otherwise stated, "multiple" means two or more.

[0067] The embodiments of this application will now be described in further detail with reference to the accompanying drawings.

[0068] Firstly, this application provides a one-to-one pressure dosing method for wastewater treatment, referring to... Figure 1 This includes the following steps:

[0069] S110. Obtain the target dosing flow rate value, substitute the target dosing flow rate value into the preset pressure-flow rate correspondence formula, and calculate the pressure value required by the dosing tank.

[0070] In the pressure-flow correspondence formula, the pressure value is positively correlated with the square of the flow rate value.

[0071] In this embodiment, an alternating dosing system with two tanks, A and B, is used, such as... Figure 2 As shown in the diagram. Each dosing tank is equipped with an independent pressure sensor and level sensor, and its respective dosing valve and inlet valve are controlled by a PLC. The system has an automatic switching mechanism; when a working dosing tank (e.g., tank A) reaches a low level, it automatically switches to another dosing tank (tank B) that is full to continue dosing, ensuring uninterrupted dosing. The two dosing tanks work alternately, serving as backups for each other.

[0072] The pressure-flow rate relationship was obtained through pre-calibration. The calibration process involved measuring the corresponding flow rate under stable operating conditions using different pressure values ​​as input, thus establishing the relationship between pressure P and flow rate Q. Data analysis revealed a linear relationship between the square of pressure and flow rate, i.e., P = kQ², where k is a pipeline characteristic coefficient related to factors such as pipeline layout and liquid properties.

[0073] Specifically, in practical applications, the target flow rate is first input, the theoretical pressure value is calculated using a formula, the proportional valve opening is adjusted by PLC analog signal conversion to stabilize the tank pressure within the specified pressure range, and then the dosing process is started.

[0074] S120. The liquid level change value is measured by the liquid level sensor to obtain the actual flow rate value.

[0075] In this embodiment, a liquid level sensor is used to measure changes in the liquid level in the dosing tank. The liquid level drop value ΔH is recorded within a preset time interval. Combined with the cross-sectional area S of the dosing tank, the actual volumetric flow rate can be calculated. This method replaces the flow meter to solve problems encountered with flow meters (scaling, staining, decreased accuracy, etc.) while ensuring measurement accuracy. To reduce the impact of liquid level fluctuations, the system uses the sliding average of multiple measurements as the final measured flow rate value.

[0076] S130. Compare the target dosing flow rate with the measured flow rate to determine the flow error rate.

[0077] In this embodiment, the flow error rate ε is calculated using a relative error method, i.e., ε = (Q_measured - Q_target) / Q_target × 100%. The system establishes an error assessment database to record the error change trends under different operating conditions, which is used for subsequent fault diagnosis and predictive maintenance.

[0078] Specifically, the system divides the error rate into normal range, warning range, and alarm range, and displays them in different colors on the control interface, making it easy for operators to intuitively judge the system's operating status.

[0079] S140. When the flow error rate exceeds the preset range, adjust the pressure value of the dosing tank for calibration until the flow error rate is within the preset range.

[0080] In this embodiment, multiple error ranges are preset. For example, the first level, ±5%, is within the normal range and requires no adjustment; the second level, ±5% to ±15%, requires automatic calibration; and the third level, exceeding ±15%, triggers an alarm and requests manual intervention. The system uses a lookup table method to establish the correspondence between the error rate and the pressure correction value, avoiding complex model calculations.

[0081] Specifically, when the flow error rate is -8%, the system queries a preset calibration table to determine that the current pressure value needs to be increased by 8%. For example, if the current pressure is 0.5 MPa, the adjusted pressure value is 0.54 MPa. The system performs pressure regulation through a proportional control valve, and after each adjustment, it waits for the system to stabilize (approximately 30 seconds) before performing the next error assessment, until the error rate returns to the normal range. In actual operation, the program performs multiple calibrations within an error range of 5-15%. Specifically: if the pressure increases to exceed the preset safety tank pressure and the actual dosing flow rate still does not return to the normal range, calibration stops; or, if the pressure decreases to below the preset lower limit tank pressure and the actual dosing flow rate still does not return to the normal range, calibration also stops, and an abnormal alarm may be triggered.

[0082] Furthermore, the system can also be set to stop calibration and trigger an abnormal alarm if the error does not improve after adjusting for a preset number of times.

[0083] In one embodiment, refer to Figure 3 In step S110, the pressure-flow correspondence is obtained through calibration, specifically including the following steps:

[0084] S111. Select multiple pressure values, and set the pressure values ​​from low to high within the allowable working pressure range.

[0085] This embodiment is based on the Bernoulli equation and uses the least squares method to fit the pressure and flow rate data. For example... Figure 4 As shown, the horizontal axis represents the square of the flow rate, and the vertical axis represents the pressure value (unit: MPa). In the fitting equation P=MQ²+N, M reflects the pipeline characteristics (related to pipe diameter, layout, etc.), and N reflects the static pressure loss. The figure shows that the measured data points are basically uniformly distributed on the fitted line within the range of 100-300 for the square of the flow rate, and the correlation coefficient R² reaches 0.99, indicating a significant linear relationship between pressure and the square of the flow rate.

[0086] Specifically, the system establishes a database to record pressure values, flow rates, and fitting parameters during the calibration process. Figure 4 For example, when the square of the flow rate is 100, the corresponding pressure is approximately 0.1 MPa; when the square of the flow rate increases to 200, the pressure rises to approximately 0.2 MPa. Through this linear correspondence, the system can quickly calculate the required pressure based on the target flow rate. For instance, if a flow rate square of 150 is required, the required pressure can be calculated directly from the graph or by substituting it into the fitted equation, yielding approximately 0.15 MPa.

[0087] Furthermore, this embodiment calibrates two dosing tanks, A and B, separately. First, tank A undergoes full-process calibration: selecting 5-10 points, calibration is performed from low to high, with the pressure setting range being the allowable working range. This range is based on experience; the output pressure values ​​corresponding to the required minimum and maximum dosing flow rates are found through on-site debugging to further determine the calibration pressure setting range. Steady-state flow data is recorded for 30 seconds at each pressure point. After completing the calibration of tank A and saving the parameters, the same calibration process is performed on tank B. Considering that there may be slight differences in the piping layout of the two dosing tanks (such as pipe length, number of bends, etc.), the system establishes separate pressure-flow correspondence formulas for each, ultimately obtaining two sets of M and N values.

[0088] S112. Calculate the actual average flow rate corresponding to each of the above pressure values ​​by the change in liquid level of the dosing tank within a preset time period.

[0089] This embodiment uses a level sensor to measure changes in the liquid level in the dosing tank. At each pressure point, the system maintains a stable dosing time of 30 seconds, and the average flow rate is calculated based on the change in liquid level.

[0090] Specifically, assuming the radius of the dosing tank is 0.25 meters, when the pressure stabilizes at 0.5 MPa, if the liquid level drops from 1200 mm to 1180 mm within 30 seconds, the corresponding flow rate Q = cross-sectional area × liquid level change / time = 0.196 × 0.02 × 120 = 0.471 m³ / h. The system samples the instantaneous flow rate five times within 30 seconds and averages the results to eliminate the influence of random errors. The liquid level curve and calculated flow rate are displayed in real time on the operation screen, allowing operators to intuitively monitor the calibration process.

[0091] S113. Fit multiple set pressure values ​​with the corresponding measured average flow rate values ​​using the relationship P=MQ²+N, and determine the values ​​of the fitting coefficients M and N.

[0092] Where P is the pressure value of the dosing tank and Q is the dosing flow rate.

[0093] In this embodiment, based on the Bernoulli equation, the least squares method is used to fit the pressure and flow rate data. In the fitting equation P=MQ²+N, M reflects the pipeline characteristics (related to pipe diameter, layout, etc.), and N reflects the static pressure loss. The system substitutes 10 sets of pressure and flow rate data into the equation and solves for the optimal fitting parameters through matrix operations.

[0094] Specifically, the system establishes a database to record pressure values, flow rates, and fitting parameters during the calibration process.

[0095] S114. Determine whether the fitting correlation coefficient exceeds the correlation coefficient of the preset fitting formula. When the fitting correlation coefficient exceeds the correlation coefficient of the preset fitting formula, complete the calibration of the pressure-flow correspondence formula.

[0096] In this embodiment, the correlation coefficient of the fitting formula is set to 0.99, meaning the correlation coefficient R² of the pressure and flow data must be ≥ 0.99. The system evaluates the fitting quality by calculating the sum of squared deviations between the measured and fitted values. Recalibration is triggered under the following circumstances: first use of the device, 30 days of continuous operation, restart after a 30-day shutdown, after pipeline modification, and calibration failure. It is understood that the number of days of continuous operation and the number of days of shutdown before restart can be dynamically adjusted according to actual conditions.

[0097] Specifically, when the system calculates R²=0.995, it indicates that the calibration result is reliable, and the system automatically saves the fitted parameters and switches to normal operating mode. If R²<0.99, the system will issue an alarm indicating "calibration abnormality" and display possible causes (such as unstable pressure, level gauge malfunction, etc.). Operators can view the calibration curve, identify the abnormal point, and recalibrate.

[0098] In one embodiment, refer to Figure 5 The pressure-flow correspondence is obtained through calibration, and also includes the following steps:

[0099] S115. Determine whether the dosing tank has reached a low liquid level by monitoring the liquid level.

[0100] In this embodiment, a three-level liquid level early warning mechanism is established. Three liquid level points—high, medium, and low—are set in the drug storage module, representing 80%, 50%, and 20% of the total liquid level in the tank, respectively. The system collects liquid level data in real time through a liquid level sensor and uses a simple liquid level judgment table to convert the liquid level signal into a percentage for automatic control during the calibration process.

[0101] Specifically, the system will trigger a low liquid level warning when the liquid level drops below 20%. To ensure the accuracy of calibration data, the system checks whether the current liquid level meets the minimum liquid level requirement before recording liquid level changes at each pressure point. For example, if calibration is currently underway at a 0.2 MPa pressure point and the liquid level is expected to drop by 20 mm within 30 seconds, the system will predict whether the final liquid level will drop below 300 mm, thus deciding in advance whether to replenish the drug.

[0102] S116. When the dosing tank reaches a low liquid level, close the dosing valve, pause calibration, and open the inlet valve to add chemicals to a high liquid level.

[0103] In this embodiment, a sequential control strategy is used for automatic drug replenishment. When a low liquid level signal is detected, the control system first closes the drug dosing solenoid valve and records the parameters of the currently incomplete calibration pressure point. Then, it sends a drug replenishment command to the PLC, which starts the drug inlet pump and drug inlet valve according to a preset program, while simultaneously displaying the "Replenishing Drugs" status on the operation screen.

[0104] S117. After adding the drug to the high liquid level, close the inlet valve and continue the calibration.

[0105] In this embodiment, a calibration breakpoint continuation function is designed. After the medication is replenished, the system first enters a 2-minute settling period to allow the liquid level to stabilize. Subsequently, it queries the breakpoint record table for the last calibration pressure value and completed data points, and automatically continues to execute the unfinished calibration steps.

[0106] Specifically, if the system is undergoing calibration at the 6th pressure point (1.1 MPa) before medication replenishment, after medication replenishment, when the system re-intakes air and stabilizes the pressure, it will monitor whether the pressure is stable at the 6th pressure point. Then, based on the pressure monitoring results, the 6th point will be recalibrated to verify the accuracy of the calibration data. Then, the 30-second flow rate recording at that pressure point will be repeated. The data from the first 5 pressure points remains unchanged, and data from the 6th to the 10th pressure points will continue to be collected. This breakpoint continuation mechanism significantly improves calibration efficiency and avoids repetitive work.

[0107] S118. When the correlation coefficient of the fit does not exceed the correlation coefficient of the preset fitting formula, the calibration step is re-executed.

[0108] In this embodiment, the system establishes a calibration quality assessment mechanism. After data collection at all pressure points is completed, the correlation coefficient R² is calculated using the least squares method. If R² < 0.99, the cause of the anomaly is manually analyzed by querying a preset fault characteristic table and identifying potential fault points based on parameters such as pressure fluctuation and liquid level change trends. Alternatively, the system can automatically query a preset fault characteristic table and identify potential fault points based on parameters such as pressure fluctuation and liquid level change trends.

[0109] Specifically, when calibration fails, the system first performs a self-check: checking if the pressure sensor signal is stable (fluctuation <1%), if the level sensor is working properly (signal continuity), and if each valve is operating correctly. If the equipment is normal, recalibration is performed, while extending the stabilization time for each pressure point to 45 seconds to obtain more stable flow data. If the requirements are still not met after three consecutive calibrations, the system will issue an alarm and prompt for manual inspection.

[0110] In one embodiment, refer to Figure 6 In step S140, when the flow error rate exceeds the preset range, the pressure value of the dosing tank is adjusted for calibration, specifically including the following steps:

[0111] S141. When the absolute value of the flow error rate exceeds the first preset threshold but is less than the second preset threshold, the output pressure value is automatically adjusted according to the current output pressure and the flow error rate.

[0112] This application provides two pressure adjustment methods: adjustment using a correspondence formula and adjustment using a preset lookup table, establishing a correspondence table between the error rate and the correction coefficient. One method can be selected based on the specific application scenario. When using the correspondence formula, if the flow error rate is negative, the adjusted pressure value equals the current pressure value multiplied by (1 + the absolute value of the flow error rate); if the flow error rate is positive, the adjusted pressure value equals the current pressure value multiplied by (1 - the absolute value of the flow error rate). The current pressure value is the pressure value obtained from the previous calibration. If it is the first calibration, the current pressure value is the pressure value calculated based on the pressure-flow correspondence formula. When adjusting the output pressure value using the preset lookup table, this embodiment sets a two-level flow error warning mechanism: a first preset threshold of 5% and a second preset threshold of 15%. The system establishes a correspondence table between the error rate and the pressure correction coefficient using the lookup table method, avoiding complex calculations. For example, when the error rate is in the range of 5%-7%, the pressure correction factor is 1.05~1.07; when the error rate is in the range of 7%-10%, the correction factor is 1.07~1.1; and when the error rate is in the range of 10%-15%, the correction factor is 1.1~1.15.

[0113] In this embodiment, the system establishes independent calibration parameter databases for both dosing tanks A and B. When tank A is running, its pressure-flow relationship and historical calibration data are used for control; when switching to tank B, the corresponding parameters for tank B are automatically invoked. This separate tank control strategy takes into account the potential differences between the two dosing systems during actual installation and use, thus improving dosing accuracy.

[0114] Understandably, the operating parameters of either A or B can be applied to both dosing tanks simultaneously to improve calibration efficiency and achieve non-stop calibration in actual operation.

[0115] S142. Output according to the adjusted pressure value through the proportional valve.

[0116] This embodiment employs a segmented regulation strategy to control the proportional valve output. The system divides the pressure range of 0-1 MPa into 10 intervals and establishes a segmented linear correspondence table between valve opening and pressure. Different PID parameters are used for each interval to ensure that the regulation process is both fast and stable.

[0117] Specifically, when the pressure needs to be adjusted from 0.3 MPa to 0.315 MPa, the system first determines the target pressure range (0.2-0.4 MPa) and calls the corresponding PID parameter group for that range. The proportional valve gradually adjusts the output according to the preset rate of change, while the pressure sensor provides real-time feedback to ensure that the pressure remains stable at the target value.

[0118] S143. When the absolute value of the flow error rate after calibration is less than the first preset threshold, stop automatic calibration.

[0119] This embodiment establishes a flow error assessment database to record the error change trend after each calibration. The system calculates the average flow rate every 30 seconds, and the calibration is considered successful when the error rate is less than 5% for three consecutive times. To avoid error jitter, the system uses a moving average method to process the raw data.

[0120] Specifically, assuming the error rate calculated after calibration is -4.8% for the first calculation, -4.2% for the second, and -4.5% for the third, with the absolute values ​​of the three error rates all less than 5% and showing a stable trend, the system considers the calibration to be successful and continues operation at the current pressure setpoint. Simultaneously, the initial error, adjustment process, and final result of this calibration are recorded in the database for subsequent system optimization.

[0121] S144. When the absolute value of the flow error rate cannot be made less than the first preset threshold after exceeding the preset calibration number, and the tank pressure exceeds the preset safe working pressure value, stop automatic calibration and trigger an alarm prompt for recalibration.

[0122] In this embodiment, the calibration cycle is set to 3 times, and the preset pressure value is 0.4 MPa. The system records the number of calibrations using a counter and establishes an experience-based pressure over-limit judgment table. When the error still exceeds 5% after three consecutive calibrations, and the current pressure has reached 0.4 MPa, the system determines that the current operating condition has exceeded the automatic calibration capability range.

[0123] Specifically, if the system's error is -8% after the first calibration, -7% after the second, and still -6% after the third, and the final pressure reaches 0.42 MPa, exceeding the preset pressure value of 0.4 MPa, then automatic calibration will stop. The system will trigger an alarm, displaying the message "Calibration pressure exceeded limit, please recalibrate" on the operation screen, and simultaneously recording the current operating parameters, including pressure value, flow rate, and error rate, for technicians to analyze the fault and optimize calibration parameters.

[0124] In one embodiment, refer to Figure 7 In step S141, the output pressure value is automatically adjusted based on the current output pressure and flow error rate, specifically including the following steps:

[0125] S1411. When the flow error rate is negative, the adjusted pressure value is equal to the current pressure value multiplied by (1 + the absolute value of the flow error rate).

[0126] In this embodiment, a proportional adjustment method is used to handle negative flow rate errors. When the actual flow rate is detected to be less than the target flow rate, it indicates that the current pressure is insufficient, and the pressure needs to be increased proportionally to the error. The system sets a pressure adjustment limit table, and sets the maximum adjustment step size according to different pressure ranges to avoid system instability caused by excessively large single adjustments.

[0127] S1412. When the flow error rate is positive, the adjusted pressure value is equal to the current pressure value multiplied by (1 - the absolute value of the flow error rate).

[0128] The current pressure value is the pressure value obtained from the last calibration. If it is the first calibration, the current pressure value is the pressure value calculated according to the pressure-flow correspondence formula.

[0129] In this embodiment, a decreasing adjustment strategy is designed to address the positive flow error. The system establishes a pressure attenuation coefficient table, and considering the nonlinear relationship between flow rate and pressure, different attenuation rates are adopted for different error ranges to ensure that the adjustment process is both accurate and stable.

[0130] Furthermore, this embodiment also designs an adaptive adjustment mechanism based on the system's operating characteristics. Specifically, when tank A is running, the pressure adjustment value needs to consider the following factors: the influence coefficient of historical adjustment effect α = 1 ± 0.2 × (1 - E_last / E_current), where E_last is the error rate after the last adjustment and E_current is the current error rate. When the adjustment effect improves, the adjustment range is reduced; the influence coefficient of dosing tank liquid level β = 1 + 0.1 × (H_max - H_current) / H_max, where H_current is the current liquid level height and H_max is the maximum liquid level of the tank. As the liquid level decreases, the pressure adjustment becomes more sensitive; the influence coefficient of continuous running time γ = 1 + 0.05 × (T_current / T_standard), where T_current is the current continuous running time and T_standard is the standard running cycle (e.g., 8 hours). This takes into account that long-term operation may cause system characteristic drift.

[0131] Therefore, when the flow error rate is negative, P_new = P_current × (1 + |A|) × α × β × γ; when the flow error rate is positive, P_new = P_current × (1 - |A|) × α × β × γ, where |A| is the absolute value of the flow error rate. For example, in a certain adjustment of tank A, the error rate after the last adjustment was -10%, and the current error rate is -8%, so α = 0.95 is calculated; the current liquid level is 40% of the maximum liquid level, so β ​​= 1.06 is calculated; it has been running continuously for 6 hours, so γ = 1.0375 is calculated; the current pressure is 0.3 MPa, and the flow error rate is -8%, so the adjusted pressure value is 0.34 MPa. When switching to tank B, the system will reset the continuous running time counter, but retain the historical adjustment effect data to ensure the smoothness of the switching process. Through this multi-factor adaptive adjustment mechanism, the system can better adapt to the dosing needs under different operating conditions, improving the adjustment accuracy and stability.

[0132] In one embodiment, refer to Figure 8 The method also includes the following steps:

[0133] S210. When the flow error rate is negative after multiple consecutive calibrations and exceeds the first preset threshold, it is determined to be a risk of blockage in the discharge pipe, triggering a blockage alarm in the discharge pipe and prompting for recalibration.

[0134] This embodiment establishes a fault feature database to identify the risk of blockage in the discharge pipe. The system sets three consecutive calibrations as the judgment cycle, recording the error rate and pressure value change trend after each calibration. When it is found that the error rate is negative for three consecutive times and is greater than 5%, even if the pressure continues to increase but the flow rate remains low, the system matches this feature with the blockage patterns in the fault database.

[0135] Specifically, suppose the system's flow error rates in three consecutive calibrations are -6.5%, -7.2%, and -8.1%, respectively, and the pressure gradually increases from the initial 0.3 MPa to 0.35 MPa, but the actual flow rate still fails to reach the target value. This phenomenon of increasing pressure but persistently low flow rate is consistent with the characteristic of gradual blockage in the discharge pipe. The system will trigger a "pipeline blockage warning," displaying a red warning sign on the control panel and providing the following suggested operation: "Please check the discharge pipe and perform backflushing. Recalibration is required after processing."

[0136] Furthermore, this embodiment performs cross-validation of faults by comparing the operating data of two dosing tanks, A and B. For example, if the flow error rates of tank A after three consecutive calibrations are -6.5%, -7.2%, and -8.1%, respectively, while tank B is operating normally during the same period, the system is more likely to determine that the problem is a blockage in the pipeline of tank A rather than a fault in the shared system components. When the system triggers an alarm, it will suggest switching to the normally operating tank B first, while simultaneously inspecting tank A. Similarly, when a potential leak is detected in a dosing tank, the system will record the historical pressure and flow data of that tank and compare it with the data of another normally operating dosing tank to help maintenance personnel quickly locate the fault.

[0137] S220. When the flow error rate is positive after multiple consecutive calibrations and exceeds the first preset threshold, it is determined that there is a risk of proportional valve failure or leakage in the dosing pipe, triggering the corresponding alarm and prompting for maintenance and troubleshooting.

[0138] In this embodiment, a bidirectional diagnostic strategy is employed to distinguish between proportional valve malfunctions and pipeline leaks. The system pre-defines typical characteristics of both types of malfunctions in its operating condition database: proportional valve malfunctions typically manifest as a mismatch between valve opening and pressure, while pipeline leaks are characterized by normal pressure but abnormally high flow rates. Through a logic decision tree, potential fault points can be quickly located.

[0139] Specifically, when the system detects flow error rates of +7.8%, +8.5%, and +9.2% in three consecutive calibrations, it first analyzes the correlation between pressure and valve opening. If the pressure display shows 0.25 MPa but the actual valve opening deviates significantly from the standard curve, the system determines it is a proportional valve malfunction and triggers a "proportional valve abnormality" warning. If the pressure and valve opening match but the flow rate remains excessively high, it determines there is a risk of pipeline leakage and triggers a "pipeline leakage check" prompt. Different alarm types are configured with different warning colors and handling suggestions, such as "Please check the proportional valve feedback signal" or "Please inspect the pipeline for leaks." Simultaneously, the system automatically records complete operating data at the time of the fault, including parameters such as pressure, flow rate, and valve opening, providing a basis for subsequent maintenance.

[0140] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0141] Secondly, this application provides a one-to-one pressure dosing system for wastewater treatment. The one-to-one pressure dosing system for wastewater treatment of this application will be described below in conjunction with the above-mentioned one-to-one pressure dosing method for wastewater treatment.

[0142] Reference Figure 9 A one-to-one pressure dosing system for wastewater treatment, comprising:

[0143] Dosing tank, pressure sensor, level sensor, proportional valve and controller;

[0144] The pressure sensor is used to measure the current pressure value of the dosing tank;

[0145] The level sensor is used to measure the change in liquid level in the dosing tank;

[0146] The proportional valve is used to regulate the pressure value of the dosing tank;

[0147] The controller is electrically connected to the pressure sensor, the level sensor and the proportional valve respectively, and is used to execute the above-mentioned one-to-one pressure dosing method for wastewater treatment.

[0148] In one embodiment, the system further includes:

[0149] The inlet valve is used to replenish the drug solution in the dosing tank;

[0150] Dosing valve, used to control the output of liquid medicine;

[0151] The controller is also electrically connected to the inlet valve and the dosing valve to control the inlet and dosing process based on the measurements from the level sensor.

[0152] In one embodiment, this application provides a dosing device, the internal structure of which can be shown in the following diagram. Figure 10 As shown, the dosing device includes a processor, memory, and network interface connected via a system bus. The processor provides computational and control capabilities. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs in the non-volatile storage medium. The database stores data. The network interface allows communication with external terminals via a network connection. When the computer program is executed by the processor, it implements a one-to-one pressure dosing method for wastewater treatment.

[0153] Those skilled in the art will understand that Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the dosing device to which the present application is applied. A specific dosing device may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0154] In one embodiment, a dosing apparatus is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above method embodiments.

[0155] Those skilled in the art will understand that all or part of the processes in the methods of the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments of the above methods. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, or optical storage, etc. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc.

[0156] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A one-to-one pressure dosing method for wastewater treatment, characterized in that, Includes the following steps: Obtain the target dosing flow rate value, substitute the target dosing flow rate value into the preset pressure-flow rate correspondence formula, and calculate the pressure value required by the dosing tank. In the pressure-flow rate correspondence formula, the pressure value is proportional to the square of the flow rate value. The measured flow rate is obtained by measuring the change in liquid level using a liquid level sensor. By comparing the target dosing flow rate with the measured flow rate, the flow error rate is determined. When the flow error rate exceeds the preset range, the pressure value of the dosing tank is adjusted for calibration until the flow error rate is within the preset range. The pressure-flow correspondence is obtained through calibration, specifically including the following steps: Multiple pressure values ​​are selected, and the pressure values ​​are set from low to high within the allowable working pressure range; The actual average flow rate corresponding to each of the above pressure values ​​is calculated by the change in liquid level in the dosing tank within a preset time period. Multiple set pressure values ​​are fitted to the corresponding measured average flow rate values ​​using the relationship P=MQ²+N to determine the values ​​of fitting coefficients M and N, where P is the pressure value of the dosing tank and Q is the dosing flow rate value. Determine whether the fitting correlation coefficient exceeds the correlation coefficient of the preset fitting formula. When the fitting correlation coefficient exceeds the correlation coefficient of the preset fitting formula, complete the calibration of the pressure-flow correspondence formula.

2. The one-to-one pressure dosing method for wastewater treatment according to claim 1, characterized in that, The pressure-flow correspondence is obtained through calibration, and also includes the following steps: Use liquid level monitoring to determine if the dosing tank has reached a low liquid level; When the dosing tank reaches a low liquid level, close the dosing valve, pause calibration, and open the inlet valve to add chemicals to a high liquid level. After adding the drug to the high liquid level, close the inlet valve and continue the calibration process; If the correlation coefficient of the fitting does not exceed the correlation coefficient of the preset fitting formula, the calibration step is re-executed.

3. The one-to-one pressure dosing method for wastewater treatment according to claim 1, characterized in that, When the flow error rate exceeds the preset range, the pressure value of the dosing tank is adjusted for calibration, specifically including the following steps: When the absolute value of the flow error rate exceeds the first preset threshold but is less than the second preset threshold, the output pressure value is automatically adjusted according to the current output pressure and the flow error rate. The pressure is output according to the adjusted pressure value through a proportional valve; Automatic calibration stops when the absolute value of the calibrated flow error rate is less than the first preset threshold. If the absolute value of the flow error rate cannot be reduced to less than the first preset threshold after exceeding the preset calibration number, and the tank pressure exceeds the preset safe working pressure value, automatic calibration will stop and an alarm will be triggered to prompt recalibration.

4. The one-to-one pressure dosing method for wastewater treatment according to claim 3, characterized in that, The output pressure value is automatically adjusted based on the current output pressure and flow error rate, specifically including the following steps: When the flow error rate is negative, the adjusted pressure value is equal to the current pressure value multiplied by (1 + the absolute value of the flow error rate). When the flow error rate is positive, the adjusted pressure value is equal to the current pressure value multiplied by (1 - the absolute value of the flow error rate); The current pressure value is the pressure value obtained from the previous calibration. If it is the first calibration, the current pressure value is the pressure value calculated according to the pressure-flow correspondence formula.

5. The one-to-one pressure dosing method for wastewater treatment according to claim 4, characterized in that, The method further includes the following steps: When the flow error rate becomes negative and exceeds the first preset threshold after multiple consecutive calibrations, it is determined to be a risk of drug discharge pipe blockage, triggering a drug discharge pipe blockage alarm and prompting recalibration. When the flow error rate is positive after multiple consecutive calibrations and exceeds the first preset threshold, it is determined that there is a risk of proportional valve failure or leakage in the dosing pipe, triggering a corresponding alarm and prompting for maintenance and troubleshooting.

6. A one-to-one pressure dosing system for wastewater treatment, characterized in that, include: Dosing tank, pressure sensor, level sensor, proportional valve and controller; The pressure sensor is used to measure the current pressure value of the dosing tank; The liquid level sensor is used to measure the change in liquid level in the dosing tank. The proportional valve is used to adjust the pressure value of the dosing tank; The controller is electrically connected to a pressure sensor, a liquid level sensor, and a proportional valve, respectively, and is used to execute the one-to-one pressure dosing method for wastewater treatment as described in any one of claims 1-5.

7. A one-to-one pressure dosing system for wastewater treatment according to claim 6, characterized in that, The system also includes: The inlet valve is used to replenish the drug solution in the dosing tank; Dosing valve, used to control the output of liquid medicine; The controller is also electrically connected to the inlet valve and the dosing valve to control the inlet and dosing process based on the measured values ​​of the liquid level sensor.

8. A dosing device, characterized in that, It includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the one-to-one pressure dosing method for wastewater treatment as described in any one of claims 1-5.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the one-to-one pressure dosing method for wastewater treatment as described in any one of claims 1-5.

Images