Chemical liquid quantitative loading and overflow protection system and method

Abstract

The invention relates to the technical field of chemical liquid loading, in particular to a chemical liquid quantitative loading and overflow protection system and method.The system adopts double flowmeters, a wagon balance and double anti-overflow switches to form multiple detection units, data fusion and dynamic calibration are achieved through a main controller, and metering precision is ensured; during loading, the main controller adjusts the opening degree of the pneumatic valve in a grading mode according to a flow accumulated value and wagon balance data, when the data reaches 90% of a set value, the small flow mode is switched, and loading is automatically stopped when the data reaches the set value; the anti-overflow module adopts a double-switch design, and differential interlocking protection is implemented in combination with a loading stage; meanwhile, a third-order lag compensation model is introduced to eliminate wagon balance measurement errors, and control response is optimized through a state space algorithm; according to the system, through multi-sensor redundancy configuration and closed-loop control logic, the problems of large metering deviation, overflow protection lagging, insufficient system reliability and the like in traditional truck loading are effectively solved, and the safety of dangerous chemical truck loading is remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of chemical liquid loading technology, specifically a chemical liquid quantitative loading and overflow protection system and method. Background Technology

[0002] In the chemical industry, especially in the storage and transportation of highly corrosive, volatile, and toxic hazardous chemicals such as caustic soda, hydrochloric acid, and sodium hypochlorite, the safety and metering accuracy of liquid quantitative loading have always been pressing technical challenges for the industry. Traditional loading operations, which rely primarily on a combination of manual operation and basic instrument monitoring, suffer from the following technical deficiencies:

[0003] 1. Insufficient metering accuracy: Existing systems mostly use a single flow meter (such as a mass flow meter) to monitor the loading volume. However, due to factors such as changes in the physical properties of the medium (such as temperature and density fluctuations), pipeline vibration, and long-term wear and tear of equipment, metering errors are easily accumulated, causing the loading volume deviation to exceed the allowable range. Such deviations not only require secondary weighing or repeated loading and unloading, reducing operational efficiency, but also increase the risk of hazardous chemical leaks and personnel exposure.

[0004] 2. Lagging overflow protection: Overflow detection mainly relies on manual observation or a single liquid level switch. The response speed is limited by the operator's experience and environmental conditions (such as nighttime or rainy / foggy weather, which are not convenient for observation). There is a lag, which can easily lead to overflow. Moreover, it is impossible to shut off the overflow in time, which increases the risk of leakage accidents.

[0005] 3. System reliability deficiencies: Current quantitative loading systems generally suffer from insufficient redundancy design. For example, a single point of failure in a sensor or control unit may lead to malfunction; although some solutions introduce overflow detection functions, their coordination with the flow control system is insufficient, the protection logic is fragmented, and it is difficult to achieve real-time verification and linkage control of multiple parameters (such as flow rate, weight, and liquid level).

[0006] Therefore, there is an urgent need to develop a chemical liquid quantitative loading system that integrates high-precision multi-source data fusion, dynamic hierarchical interlocking, and redundant protection functions to solve technical bottlenecks such as metering error accumulation, overflow response lag, and insufficient system reliability, and to meet the high safety and automation requirements of hazardous chemical storage and transportation. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide a chemical liquid quantitative loading and overflow protection system that integrates IoT sensing technology and multi-level safety interlocking mechanisms to achieve closed-loop data management throughout the loading process, thereby eliminating the risk of metering deviation and overflow at the source.

[0008] The technical solution adopted by this invention to solve its technical problem is:

[0009] A quantitative loading and overflow protection system for chemical liquids includes: a metering unit comprising several flow meters, with at least two flow meters installed on each loading branch pipe for real-time monitoring of the medium flow rate; a pneumatic regulating valve installed on the loading branch pipe for regulating the medium flow rate; a weighing module including a weighbridge, with one weighbridge installed at each loading station; an overflow prevention module with two overflow prevention switches installed at the end of the loading arm for monitoring the liquid level in the tanker; a monitoring module with one camera installed at each loading station for monitoring the loading process; and a main controller connected to the weighbridge, flow meters, pneumatic regulating valve, overflow prevention switches, and camera for receiving data transmitted from each component and controlling the operation of each component.

[0010] As a preferred embodiment, a further technical solution of the present invention is:

[0011] Preferably, it also includes a data storage device connected to the main controller, used to store video data from the camera, metering data from the flow meter and weighbridge, and the opening degree of the pneumatic regulating valve and the anti-overflow switch.

[0012] Preferably, each loading branch pipe is equipped with two flow meters, and the distance between the two flow meters is greater than or equal to 10 times the inner diameter of the loading branch pipe.

[0013] Preferably, it also includes a pulse damper, which is installed on the loading branch pipe and located downstream of the flow meter.

[0014] Preferably, it also includes a density sensor, which is mounted on the loading branch pipe and connected to the main controller.

[0015] This invention also discloses a method for quantitative loading and overflow protection of chemical liquids, which uses a quantitative loading and overflow protection system for chemical liquids during loading. The specific method includes:

[0016] The tanker truck drives into the loading station and parks on the weighbridge. The loading arm connects to the tanker truck. After the main controller receives the signal to allow loading, the operator inputs the loading quantity setting value Q0 and starts loading.

[0017] The flow meter monitors the flow rate of the medium in the loading branch pipe in real time and transmits the flow data to the main controller. The weighbridge weighs the load in real time and transmits the weighing value to the main controller. The main controller performs cumulative calculation on the received flow data to obtain the cumulative flow value corresponding to each flow meter and dynamically aligns the cumulative flow value of each flow meter with the weighbridge data.

[0018] When the cumulative flow value of any flow meter or the measurement data of the weighbridge reaches 90% of Q0, the main controller generates a "about to be full" signal and outputs it to the host computer; when the main controller does not generate a "about to be full" signal, the main controller uses a large flow rate opening adjustment algorithm to adjust the opening of the pneumatic regulating valve; after the main controller generates a "about to be full" signal, the main controller uses a small flow rate opening adjustment algorithm to adjust the opening of the pneumatic regulating valve.

[0019] When the cumulative flow values ​​of any two flow meters or the cumulative flow value of any one flow meter and the measurement data of the weighbridge both reach Q0, the main controller controls the loading to stop.

[0020] Two overflow prevention switches monitor the tanker's liquid level in real time. When there is no signal indicating that the tanker is about to be full, the main controller will stop loading when both overflow prevention switches generate their trigger signals simultaneously. When the main controller generates a signal indicating that the tanker is about to be full, the main controller will stop loading when either overflow prevention switch generates its trigger signal.

[0021] Preferably, the main controller uses a third-order hysteresis compensation model to process the weighing value of the weighbridge to eliminate the nonlinear hysteresis caused by mechanical inertia. The third-order hysteresis compensation model is as follows:

[0022]

[0023] Among them, W raw This represents the raw data from the weighbridge; τ represents the lag time, and W... cal This indicates the output data after compensation, where r represents the compensation coefficient and t represents the cumulative time.

[0024]

[0025] Among them, V pipe ρ represents the volume of the loading pipeline. cal This indicates the measured density from the density sensor.

[0026] Preferably, two flow meters are installed on each loading branch pipe, and the flow data detected by the two flow meters are Q. A and Q B ;

[0027] A state-space model is constructed using multi-sensor data fusion and dynamic traffic calibration algorithms; the state model is as follows:

[0028] x k =Ax k-1 +Bu k +w k (3);

[0029] Wherein, the state vector Q fused This is represented as merged traffic. Represented as the rate of change of flow, the state matrix A is represented as... Δt represents the sampling time; the control input matrix B is B = [0, K] P ] T K P The proportional coefficient in a PID controller; the control input u k For valve opening adjustment amount; w k The covariance represents the process noise. σ q =0.1%Q max , Q max Maximum flow rate;

[0030] The observation equation is:

[0031] z k =Hx k +v k (4);

[0032] Wherein, the observation vector z k =[Q A Q B W cal ], Q A and Q B W represents the instantaneous flow rate of flow meters A and B, respectively; cal The weighing value of the weighbridge after third-order hysteresis compensation is represented by the observation matrix H as follows: v k The covariance represents the observation noise. σ A =0.2%Q max , σ B =0.2%Q max , g represents the acceleration due to gravity, based on the vibration acceleration threshold (0.5g = 4.9 m / s²). 2 Dynamically adjust the weight of the weighbridge; increase the noise standard deviation by 5 times during strong vibrations to reduce the impact of unreliable data.

[0033] State update is represented as:

[0034]

[0035] Among them, K k The Kalman gain is expressed as:

[0036] K k =P k|k-1 H T HP k|k-1 H T +R) -1 (7);

[0037] P k|k-1 =AP k-1 A T +Q (8);

[0038] covariance P k The update is represented as:

[0039] P k =(IK k H)P k|k-1 (9).

[0040] The preferred algorithm for adjusting the opening of a large flow rate is as follows:

[0041]

[0042] Among them, u k e is the valve opening adjustment value. k For flow deviation, K P K i K d These are the PID parameters; Δt represents the sampling time, and k represents the time step in the discrete time.

[0043] e k =Q set -Q fused (11);

[0044] Among them, Q set To set the flow rate, Q fused To integrate traffic;

[0045] The algorithm for adjusting the opening of small flow rates is as follows:

[0046]

[0047] Among them, K P,samll =2K P K i,small =0.5K i .

[0048] Preferably, the compensation amount is set to adjust the valve opening value u. k Compensation will be provided, and the compensation process is as follows:

[0049] u final =u k +Δu (13);

[0050] Among them, u final The final valve opening is Δu, and the compensation amount is Δu.

[0051]

[0052] Where β is the medium compensation coefficient, ρ real ρ is the actual density detected by the density sensor. std Q is the standard density of the medium. fused To integrate traffic.

[0053] The present invention, which adopts the above technical solution, has the following prominent features compared with the prior art:

[0054] 1. Significantly improved metering accuracy: By installing at least two flow meters on each loading branch pipe and dynamically aligning them with weighbridge data, a state-space model is constructed using multi-sensor data fusion and flow dynamic calibration algorithms, effectively reducing the impact of single instrument errors. At the same time, the introduction of density sensors and a third-order hysteresis compensation model eliminates metering deviations caused by fluctuations in medium properties and mechanical inertia, greatly improving the accuracy of quantitative loading.

[0055] 2. More reliable overflow protection: Two overflow protection switches are installed at the end of the loading arm. The triggering logic is dynamically adjusted according to the loading stage. When there is no signal that the loading arm is about to be full, both switches need to be triggered at the same time to stop loading. When there is a signal that the loading arm is about to be full, a single switch triggering will stop loading. This avoids false triggering and ensures rapid response in emergency situations, solving the problem of lagging protection in traditional systems.

[0056] 3. Enhanced system redundancy and safety: The use of multiple flow meter spacing settings and pulse dampers reduces flow monitoring interference. Multiple verification mechanisms are adopted for each key link (such as stopping loading when any two flow meters or the flow meter and the weighbridge data meet the standard), reducing the risk of single point failure. The data storage device stores the data of the entire process, which is convenient for traceability and improves the safety and reliability of the hazardous chemical loading process.

[0057] 4. Intelligent adjustment and efficiency optimization: The system automatically switches between high-flow and low-flow opening adjustment algorithms based on the loading progress, and corrects the valve opening through compensation, balancing loading efficiency and precise control, reducing secondary operations, and lowering the risk of hazardous chemical leaks and personnel exposure. Attached Figure Description

[0058] Figure 1 This is a flowchart of the quantitative loading and overflow protection method in an embodiment of the present invention;

[0059] Figure 2 This is a schematic diagram of the connection structure between the quantitative loading and overflow protection system in an embodiment of the present invention.

[0060] Explanation of reference numerals in the attached diagram: 1. Storage tank; 2. Supply pump; 3. Shut-off valve; 4. Pneumatic regulating valve; 5. Flow meter; 6. Loading arm; 7. Overflow prevention switch; 8. Tank truck; 9. Weighbridge; 10. Camera; 11. Loading main pipe; 12. Loading branch pipe. Detailed Implementation

[0061] The present invention will be further illustrated below with reference to specific embodiments. The purpose of this illustration is solely to provide a better understanding of the invention. Therefore, the examples given do not limit the scope of protection of the present invention.

[0062] like Figure 2 As shown in the figure, this embodiment provides a quantitative loading and overflow protection system for chemical liquids, including: a metering unit, comprising several flow meters 5, with at least two flow meters 5 installed on each loading branch pipe 12 for real-time monitoring of the medium flow rate; a pneumatic regulating valve 4, installed on the loading branch pipe 12 for regulating the medium flow rate; a weighing module, comprising a weighbridge 9, with one weighbridge 9 installed at each loading station; an overflow prevention module, with two overflow prevention switches 7 installed at the end of the loading arm 6 for monitoring the liquid level in the tank truck 8; a monitoring module, with one camera 10 installed at each loading station for monitoring the loading situation on site; and a main controller, connected to the weighbridge 9, flow meters 5, pneumatic regulating valve 4, overflow prevention switches 7, and camera 10, for receiving data transmitted from each component and controlling the operation of each component. The storage tank 1 is connected to several loading branch pipes 12 (each loading branch pipe 12 corresponds to one loading station) through the loading main pipe 11, and the loading main pipe 11 is equipped with a liquid supply pump 2 and a shut-off valve 3. The media flow direction is: storage tank 1, loading main pipe 11, loading branch pipe 12, loading arm 6, tank truck 8. The main controller (deployed in the cabinet or integrated into the upper-level DCS / SCADA system) establishes real-time data communication with the DCS control station via a redundant industrial bus (PROFIBUS DP / Modbus RTU). Weighbridge 9 is an explosion-proof weighbridge.

[0063] The weighbridge 9 and mass flow meter 5 are periodically calibrated annually by the national metrology department to ensure measurement accuracy. In addition, each loading station is equipped with a camera 10, which transmits video streams to the central control room, and the monitoring screen displays the loading situation on site in real time.

[0064] It also includes a density sensor, which is installed on the loading branch pipe 12 and connected to the main controller; it is used to calculate the subsequent compensation amount by measuring the actual density.

[0065] It also includes a data storage device, which is connected to the main controller and is used to store video data from camera 10, metering data from flow meter 5 and weighbridge 9, and the opening degree of pneumatic regulating valve 4 and anti-overflow switch 7. The data storage device can meet the requirements of a 90-day video surveillance retention period and a 1-year retention period for critical data, thus meeting the requirements for accident traceability.

[0066] It also includes a pulse damper, which is installed on the loading branch pipe 12 and located downstream of the flow meter 5.

[0067] like Figure 1As shown, this invention also discloses a method for quantitative loading and overflow protection of chemical liquids, using a quantitative loading and overflow protection system for loading chemical liquids. The specific method includes:

[0068] First, tanker truck 8 drives into the loading station and parks on weighbridge 9. Loading arm 6 connects to tanker truck 8. After the main controller receives the signal to allow loading, the operator inputs the loading quantity setting value Q0 and starts loading.

[0069] During the loading process, the flow meter monitors the flow rate of the medium in the loading branch pipe 12 in real time and transmits the flow data to the main controller. The weighbridge 9 weighs the medium in real time and transmits the weighing value to the main controller. The main controller performs cumulative calculation on the received flow data to obtain the cumulative flow value corresponding to each flow meter 5, and dynamically aligns the cumulative flow value of each flow meter 5 with the data of the weighbridge 9.

[0070] When the cumulative flow value of any flow meter 5 or the measurement data of the weighbridge 9 reaches 90% of Q0, the main controller generates a "soon to be full" signal and outputs it to the host computer. If the main controller does not generate a "soon to be full" signal, it uses a large flow rate opening adjustment algorithm to adjust the opening of the pneumatic regulating valve 4. After generating the "soon to be full" signal, the main controller uses a small flow rate opening adjustment algorithm to adjust the opening of the pneumatic regulating valve 4. When the cumulative flow value of any two flow meters 5 or the cumulative flow value of any one flow meter 5 and the measurement data of the weighbridge 9 both reach Q0, the main controller stops loading.

[0071] Two overflow prevention switches 7 monitor the liquid level of the tank truck 8 in real time. When there is no signal indicating that the tank is about to be full, the main controller will stop loading when the trigger signals of the two overflow prevention switches 7 are generated simultaneously. When the main controller generates a signal indicating that the tank is about to be full, the trigger signal of either overflow prevention switch 7 will be generated, and the main controller will stop loading.

[0072] Taking the installation of two flow meters 5 (flow meter A and flow meter B) on each loading branch pipe 12 as an example, the loading stop signal and interlocking safety protection conditions can be expressed as follows.

[0073] Stop loading signal:

[0074]

[0075] The real-time cumulative flow values ​​of mass flow meter A and mass flow meter B are respectively represented as Q. A,sum and Q B,sum Q0 is the vehicle installation setting value.

[0076] Chain safety protection conditions:

[0077] During high-volume phases: Q sum <0.9Q0. Requires simultaneous triggering by both switches:

[0078] STOP: S1=1∧S2=1(16);

[0079] During low-volume phase: Q sum ≥0.9Q0. Only one switch is required to trigger:

[0080] STOP: S1=1∨S2=1(17);

[0081] It can effectively reduce the occurrence of false triggering, while ensuring that there is no overflow during loading.

[0082] Preferably, the main controller uses a third-order hysteresis compensation model to process the weighing value of the weighbridge 9 to eliminate the nonlinear hysteresis caused by mechanical inertia. The third-order hysteresis compensation model is as follows:

[0083]

[0084] Among them, W raw This represents the raw data from weighbridge 9; τ represents the lag time, W cal This indicates the output data after compensation, where r represents the compensation coefficient and t represents the cumulative time.

[0085]

[0086] Among them, V pipe ρ represents the volume of the loading pipeline. cal This indicates the measured density from the density sensor.

[0087] In this embodiment, each loading branch pipe 12 is equipped with two flow meters 5 (which can be referred to as flow meter A and flow meter B), and the flow data detected by the two flow meters 5 are Q. A and Q B The distance between flowmeter A and flowmeter B is greater than or equal to 10 times the inner diameter of the loading branch pipe 12.

[0088] A state-space model is constructed using multi-sensor data fusion and dynamic traffic calibration algorithms; the state model is as follows:

[0089] x k =Ax k-1 +Bu k +w k (3);

[0090] Wherein, the state vector Q fused This is represented as merged traffic. Represented as the rate of change of flow, the state matrix A is represented as... Δt represents the sampling time; the control input matrix B is B = [0, K] P ] T KP The proportional coefficient in a PID controller; the control input u k For valve opening adjustment amount; w k The covariance represents the process noise. σ q =0.1%Q max , Q max Maximum flow rate;

[0091] The observation equation is:

[0092] z k =Hx k +v k (4);

[0093] Wherein, the observation vector z k =[Q A Q B W cal ], Q A and Q B W represents the instantaneous flow rate of flow meters A and B, respectively; cal The weighing value of the weighbridge after third-order hysteresis compensation is represented by the observation matrix H as follows: v k The covariance represents the observation noise. σ A =0.2%Q max , σ B =0.2%Q max , g represents the acceleration due to gravity, based on the vibration acceleration threshold (0.5g = 4.9 m / s²). 2 Dynamically adjust the weight of the weighbridge; increase the noise standard deviation by 5 times during strong vibrations to reduce the impact of unreliable data.

[0094] State update is represented as:

[0095]

[0096] Among them, K k The Kalman gain is expressed as:

[0097] K k =P k|k-1 H T HP k|k-1 H T +R) -1 (7);

[0098] P k|k-1 =AP k-1 A T +Q (8);

[0099] covariance P k The update is represented as:

[0100] P k =(IK k H)P k|k-1 (9).

[0101] The preferred algorithm for adjusting the opening of a large flow rate is as follows:

[0102]

[0103] Among them, u k e is the valve opening adjustment value. k For flow deviation, K P K i K d These are the PID parameters; Δt represents the sampling time, and k represents the time step in the discrete time.

[0104] e k =Q set -Q fused (11);

[0105] Among them, Q set To set the flow rate, Q fused To integrate traffic;

[0106] The algorithm for adjusting the opening of small flow rates is as follows:

[0107]

[0108] Among them, K P,samll =2K P K i,small =0.5K i .

[0109] Preferably, the compensation amount is set to adjust the valve opening value u. k Compensation will be provided, and the compensation process is as follows:

[0110] u final =u k +Δu(13);

[0111] Among them, u final The final valve opening is Δu, and the compensation amount is Δu.

[0112]

[0113] Where β is the medium compensation coefficient, ρ real ρ is the actual density detected by the density sensor. std Q is the standard density of the medium. fused To integrate traffic.

[0114] By introducing real-time property compensation, the problem of inaccurate valve opening caused by density deviation due to temperature fluctuations in liquids (such as caustic soda, hydrochloric acid, and sodium hypochlorite) can be solved.

[0115] It should also be noted that the system needs to be periodically calibrated and verified and the process monitored visually. A cross-calibration procedure for the dual-channel metering device should be established. The weighbridge 9 should be statically calibrated monthly using standard weights, and the flow meter 5 should be dynamically calibrated quarterly using the standard volume tube method.

[0116] The weighbridge is statically calibrated using verified standard weights; the flow meter 5 is dynamically calibrated using the standard volumetric tube method.

[0117]

[0118] Among them, V std This represents the standard volume tube volume, N is the pulse count, and ρ std This is the standard density.

[0119] This invention relates to the field of hazardous chemical storage, transportation, and loading technology in the chlor-alkali chemical industry. Addressing the metering deviations and overflow risks during the loading of highly hazardous chemicals such as caustic soda and hydrochloric acid, traditional manual operation methods suffer from low accuracy and inadequate safety interlocking mechanisms. This system achieves coordinated control of accurate metering and overflow protection through a multi-redundancy design. Its innovation lies in constructing a three-level safety protection system: First, it employs two high-precision mass flow meters (5) connected in series for metering, using a dynamic regulating valve to intelligently switch between rapid high-flow filling and precise low-flow compensation; second, it integrates a weighbridge (9) real-time weighing module, forming a multi-source data fusion and verification mechanism. The two mass flow meters (5) and the weighbridge (9) are independent metering units, triggering a cutoff when any two independent metering units reach a preset value; finally, a dual overflow prevention switch (7) is installed at the end of the loading arm (6) to achieve dual-redundant monitoring of liquid level filling. Compared to existing technologies, this invention significantly improves the automation and safety level of loading operations through redundant configuration of the metering system and optimized safety interlocking logic. It ensures metering accuracy while proactively preventing overflow risks throughout the entire process, providing safe and reliable technical support for the storage and transportation of hazardous chemicals in the chlor-alkali industry.

[0120] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. All equivalent changes made based on the description and drawings of the present invention are included within the scope of the present invention.

Claims

1. A quantitative loading and overflow protection system for chemical liquids, characterized in that, include: The metering unit includes several flow meters, with at least two flow meters installed on each loading branch pipe for real-time monitoring of the medium flow rate; A pneumatic regulating valve is installed on the loading branch pipe to regulate the flow rate of the medium. The weighing module includes a weighbridge, with one weighbridge installed at each loading station; The anti-overflow module has two anti-overflow switches at the end of the loading arm for monitoring the liquid level in the tanker. The monitoring module is equipped with one camera at each loading station to monitor the loading process on site. The main controller connects the weighbridge, flow meter, pneumatic regulating valve, overflow prevention switch, and camera. It is used to receive data transmitted from each component and control the operation of each component.

2. The chemical liquid quantitative loading and overflow protection system according to claim 1, characterized in that: It also includes a data storage device, which is connected to the main controller and is used to store video data from the camera, metering data from the flow meter and weighbridge, and the opening degree of the pneumatic regulating valve and the anti-overflow switch.

3. The chemical liquid quantitative loading and overflow protection system according to claim 1, characterized in that: Each loading branch pipe is equipped with two flow meters, and the distance between the two flow meters is greater than or equal to 10 times the inner diameter of the loading branch pipe.

4. The chemical liquid quantitative loading and overflow protection system according to claim 1, characterized in that: It also includes a pulse damper, which is installed on the loading branch pipe and located downstream of the flow meter.

5. The chemical liquid quantitative loading and overflow protection system according to claim 1, characterized in that: It also includes a density sensor, which is installed on the loading branch pipe and connected to the main controller.

6. A method for quantitative loading and overflow protection of chemical liquids, characterized in that, The loading process utilizes the chemical liquid metering and overflow protection system as described in any one of claims 1 to 5, specifically including: The tanker truck drives into the loading station and parks on the weighbridge. The loading arm connects to the tanker truck. After the main controller receives the signal to allow loading, the operator inputs the loading quantity setting value Q0 and starts loading. The flow meter monitors the flow rate of the medium in the loading branch pipe in real time and transmits the flow data to the main controller. The weighbridge weighs the load in real time and transmits the weighing value to the main controller. The main controller performs cumulative calculation on the received flow data to obtain the cumulative flow value corresponding to each flow meter and dynamically aligns the cumulative flow value of each flow meter with the weighbridge data. When the cumulative flow value of any flow meter or the measurement data of the weighbridge reaches 90% of Q0, the main controller generates a "about to be full" signal and outputs it to the host computer; when the main controller does not generate a "about to be full" signal, the main controller uses a large flow rate opening adjustment algorithm to adjust the opening of the pneumatic regulating valve; after the main controller generates a "about to be full" signal, the main controller uses a small flow rate opening adjustment algorithm to adjust the opening of the pneumatic regulating valve. When the cumulative flow values ​​of any two flow meters or the cumulative flow value of any one flow meter and the measurement data of the weighbridge both reach Q0, the main controller controls the loading to stop. Two overflow prevention switches monitor the tanker's liquid level in real time. When there is no signal indicating that the tanker is about to be full, the main controller will stop loading when both overflow prevention switches generate their trigger signals simultaneously. When the main controller generates a signal indicating that the tanker is about to be full, the main controller will stop loading when either overflow prevention switch generates its trigger signal.

7. The method for quantitative loading and overflow protection of chemical liquids according to claim 6, characterized in that: The main controller uses a third-order hysteresis compensation model to process the weighing value of the weighbridge in order to eliminate the nonlinear hysteresis caused by mechanical inertia. The third-order hysteresis compensation model is as follows: Among them, W raw This represents the raw data from the weighbridge; τ represents the lag time, and W... cal This indicates the output data after compensation, where r represents the compensation coefficient and t represents the current actual time. Among them, V pipe ρ represents the volume of the loading pipeline. cal This indicates the measured density from the density sensor.

8. The method for quantitative loading and overflow protection of chemical liquids according to claim 6, characterized in that: Two flow meters are installed on each loading branch pipe. The flow data detected by the two flow meters are Q. A and Q B ; A state-space model is constructed using multi-sensor data fusion and dynamic traffic calibration algorithms; the state model is as follows: x k =Ax k-1 +Bu k +w k ;(3); Wherein, the state vector Q fused This is represented as merged traffic. Represented as the rate of change of flow, the state matrix A is represented as... Δt represents the sampling time; the control input matrix B is B = [0, K] P ] T K P The proportional coefficient in a PID controller; the control input u k For valve opening adjustment amount; w k The covariance represents the process noise. σ q =0.1%Q max , Q max Maximum flow rate; The observation equation is: z k =Hx k +v k (4); Wherein, the observation vector z k =[Q A Q B W cal ], Q A and Q B W represents the instantaneous flow rate of flow meters A and B, respectively; cal The weighing value of the weighbridge after third-order hysteresis compensation is represented by the observation matrix H as follows: v k The covariance represents the observation noise. σ A =0.2%Q max , σ B =0.2%Q max , g represents the acceleration due to gravity, based on the vibration acceleration threshold (0.5g = 4.9 m / s²). 2 Dynamically adjust the weight of the weighbridge; increase the noise standard deviation by 5 times during strong vibrations to reduce the impact of unreliable data. State update is represented as: Among them, K k The Kalman gain is expressed as: K k =P k|k-1 H T (HP k|k-1 H T +R) -1 (7); P k|k-1 =AP k-1 From T +Q (8); covariance P k The update is represented as: P k =(I-K k H)P k|k-1 (9)。 9. The method for quantitative loading and overflow protection of chemical liquids according to claim 6, characterized in that: The algorithm for adjusting the opening of a large flow rate is as follows: Among them, u k e is the valve opening adjustment value. k For flow deviation, K P K i K d These are the PID parameters; Δt represents the sampling time, and k represents the time step in the discrete time. e k =Q set -Q fused ; (11); Among them, Q set To set the flow rate, Q fused To integrate traffic; The algorithm for adjusting the opening of small flow rates is as follows: Among them, K P,samll =2K P K i,small =0.5K i .

10. The method for quantitative loading and overflow protection of chemical liquids according to claim 9, characterized in that; Set the compensation amount to adjust the valve opening value u. k Compensation will be provided, and the compensation process is as follows: u final =u k +Δu (13); Among them, u final The final valve opening is Δu, and the compensation amount is Δu. Where β is the medium compensation coefficient, ρ real ρ is the actual density detected by the density sensor. std Q is the standard density of the medium. fused To integrate traffic.

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