Fluid metering system and method based on double-path cooperation and real-time feedback

Abstract

The invention provides a fluid metering system and method based on double-path cooperation and real-time feedback. The system comprises a main metering loop, a verification metering loop, a fluid pipeline and valve system and a control system. The main metering loop realizes fluid continuous metering control through a metering pump and a flowmeter, and the verification metering loop obtains the actual mass of fluid through a weighing sensor and a weighing container. The control system circularly executes the steps of quantitative conveying, weighing verification, coefficient calculation and application, a correction coefficient is obtained through the ratio of an actual mass value to a quantitative value, and subsequent metering parameters are corrected. On-line metering and static weighing verification are combined, closed-loop control is formed, accumulative errors are eliminated, metering precision superior to 0.2% can be stably kept for a long time without expensive equipment, reliability is high, cost is reasonable, and the method is suitable for the scene of asphalt mixture production and the like.

Description

Technical Field

[0001] This invention relates to the field of precision metering technology for asphalt mixtures and fluids, and in particular to a high-precision fluid metering system and method that achieves an accuracy better than 2‰ by working in concert with a metering pump, a flow meter and a weighing sensor. Background Technology

[0002] In asphalt mixture production, accurate metering of fluids (recycled additives, epoxy resin, etc.) is a crucial step in ensuring product quality and production safety. Currently, common metering methods include:

[0003] Volumetric metering (such as metering pumps): Its advantages are good continuity and ease of integration into production lines. However, its accuracy is affected by factors such as fluid viscosity, temperature, pressure, pump wear, and internal leakage, making long-term stability difficult to guarantee, and single-channel accuracy is usually difficult to consistently reach 2‰.

[0004] Flow meter measurement (such as mass flow meters, electromagnetic flow meters, etc.): High accuracy, but high-end flow meters are expensive, and their accuracy is also affected by fluid properties and installation conditions. Applicability is limited for small flow rates or fluids with special properties (such as high viscosity or particulate matter).

[0005] Weighing method: Considered one of the most accurate methods in static measurement, it is usually used as the measurement standard. However, its disadvantage is that it has a slow response time and is difficult to achieve continuous and uninterrupted measurement on the production line.

[0006] The shortcomings of existing technologies: Each of the above-mentioned single measurement methods has its own limitations, either being costly or lacking long-term stability and reliability, making it difficult to continuously and stably guarantee a measurement accuracy better than 2‰ in complex industrial environments.

[0007] Therefore, there is an urgent need for a measurement solution that can balance high precision, high reliability, good continuity, and reasonable cost. Summary of the Invention

[0008] To address the aforementioned technical shortcomings, the purpose of this invention is to provide a fluid metering system and method based on dual-path collaboration and real-time feedback, achieving and maintaining a fluid metering accuracy better than 2‰ over the long term.

[0009] To achieve the above objectives, the present invention adopts the following technical solution:

[0010] A fluid metering system based on dual-path coordination and real-time feedback includes:

[0011] The main metering circuit, including a metering pump and a flow meter connected in sequence, is used for continuous metering and control of fluid delivery.

[0012] A calibration metering loop, including a load cell and a weighing container placed thereon, is used to receive and weigh the fluid discharged from the main metering loop;

[0013] Fluid piping and valve systems are used to selectively direct fluids to weighing containers or downstream outlets;

[0014] The control system is communicatively connected to the metering pump, flow meter, and load cell. The control system is configured to perform the following steps: 1) control the main metering loop to deliver a preset quantitative fluid to the weighing container; 2) stop fluid delivery when the cumulative measurement value of the flow meter reaches the quantitative value; 3) obtain the actual mass value of the fluid in the weighing container through the load cell; 4) calculate a correction coefficient based on the quantitative value and the actual mass value; 5) apply the correction coefficient to the next metering control of the quantitative fluid.

[0015] Preferably, the control system calculates the correction coefficient based on the quantitative value and the actual quality value by dividing the actual quality value by the quantitative value to obtain a proportionality coefficient as the correction coefficient.

[0016] Preferably, the control system is configured to operate continuously in a cyclic manner, each cycle including one quantitative delivery, one weighing verification, and one coefficient calculation and application, and the correction coefficient calculated in this cycle is immediately applied to the metering control of the next cycle.

[0017] Preferably, the specific method of applying the correction coefficient to the metering control is as follows: the correction coefficient is used to correct the reading of the flow meter, and the corrected flow value is equal to the original reading of the flow meter multiplied by the correction coefficient; the control system determines whether the quantitative value has been reached based on the corrected flow value.

[0018] Preferably, the specific method of applying the correction coefficient to the metering control is as follows: the control parameters of the metering pump are corrected using the correction coefficient, so that the ratio of the actual output of the metering pump to the theoretical output approaches the correction coefficient.

[0019] Preferably, the valve system includes a three-way switching valve; one inlet of the three-way switching valve is connected to the output end of the main metering circuit, and the two outlets of the three-way switching valve are respectively connected to the inlet and downstream outlet of the weighing container.

[0020] Preferably, the control system is further configured to: after each weighing verification is completed, control the emptying of the weighing container and reset the weighing sensor to zero, in preparation for the next metrological verification cycle.

[0021] A fluid metering method, based on a fluid metering system with dual-path coordination and real-time feedback, includes the following steps:

[0022] S1: Set the quantitative value Qset for a single measurement;

[0023] S2: Start the main metering circuit and control the metering pump to deliver fluid to the weighing container;

[0024] S3: Monitor the cumulative flow Qall using a flow meter, and stop delivery when the monitored value reaches the quantitative value;

[0025] S4: Weigh the actual mass of the fluid inside the weighing container using a load cell.

[0026] S5: Calculate the correction factor k based on the quantitative value and the actual quality value;

[0027] S6: Apply the correction factor to the control of the next metering cycle;

[0028] S7: Empty the weighing container and zero it. Repeat steps S2 to S6 to start the next measurement cycle.

[0029] Preferably, in step S5, the correction coefficient K is calculated by the formula: K = Wactual / Qset, where Wactual is the actual mass value and Qset is the quantitative value.

[0030] Preferably, in step S6, applying the correction factor includes: in the next metering cycle, multiplying the flow meter reading by the correction factor K, and using the product as the basis for determining whether the quantitative value has been reached.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] By periodically verifying continuous online measurement with a high-precision static weighing benchmark, the cumulative error caused by factors such as equipment wear and changes in fluid properties is fundamentally eliminated. The overall measurement accuracy of the system can be controlled within 2‰ for a long time and stably, exhibiting extremely high accuracy and stability.

[0033] The system has self-diagnostic capabilities, which can automatically detect accuracy drift and immediately correct it, realizing closed-loop automated control of "measurement-verification-correction", which greatly reduces the frequency of manual intervention and calibration.

[0034] The two metering circuits are redundant. Even if one circuit (such as the flow meter) fails, the system can detect it in time by comparing abnormal errors and issue an alarm, thus avoiding batch metering errors and production accidents, and ensuring high reliability.

[0035] The system adopts an architecture of "high-precision reference (weighing) + continuous metering unit (pump and flow meter) + intelligent feedback", which eliminates the need for extremely expensive ultra-high precision flow meters. While ensuring the final accuracy, it effectively controls the system cost and is cost-effective. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the system structure of the present invention;

[0037] Figure 2 This is a flowchart of the control method of the present invention.

[0038] in:

[0039] 1. Raw material tank; 2. Piping; 3. Metering pump; 4. Flow meter; 5. Shut-off valve; 6. Weighing sensor; 7. Weighing container; 8. Discharge valve; 9. Control unit. Detailed Implementation

[0040] The invention will now be further described with reference to the accompanying drawings.

[0041] A fluid metering system based on dual-path coordination and real-time feedback includes:

[0042] Main metering circuit: includes metering pump 3 and flow meter 4 connected in sequence, used for preliminary and continuous metering and control of fluid delivery.

[0043] Verification metering circuit: includes a weighing sensor 6 and a weighing container 7 placed thereon, for receiving fluid discharged from the main metering circuit and performing high-precision static weighing.

[0044] Control system: includes control unit 9 (such as PLC or industrial computer), which is electrically connected to metering pump 3, flow meter 4 and weighing sensor 6 respectively.

[0045] Fluid piping and valve system: including necessary piping 22 and at least one switching valve for directing fluid to weighing container 7 or downstream process.

[0046] Control unit 9 is configured to execute a mandatory, cyclical metrological verification process based on quantitative values:

[0047] Parameter setting: Pre-set a quantitative value Qset as the target for each measurement.

[0048] Metering and calibration cycle start-up: The control system starts the main metering circuit (metering pump 3 and flow meter 4) to deliver fluid to the weighing container 7 based on the quantitative value Qset.

[0049] Cycle termination and weighing: When the cumulative reading of flow meter 4 reaches Qset, metering pump 3 is immediately stopped and valve is closed, isolating weighing container 7. Weighing sensor 6 measures the actual mass of the fluid inside the container.

[0050] Error Calculation and Coefficient Generation: Control Unit 9 calculates the error of this measurement and generates the correction coefficient Knew.

[0051] Error E = (Qset - Wactual)Wactual × 1000‰

[0052] The correction factor Knew = Wactual / Qset × K (or other integral correction algorithms can be used).

[0053] Real-time feedback correction: After each metering cycle, the control system immediately applies the newly calculated correction coefficient Knew to the next metering cycle. Specifically, this coefficient is used to correct the reading of flow meter 4 in the next cycle or directly correct the control command of metering pump 3, so that: the corrected flow value = the original reading of flow meter 4 × K_{new}.

[0054] Reset and preparation: Empty weighing container 7, zero the weighing platform, and prepare the system to execute the next quantitative measurement cycle based on the new correction coefficient.

[0055] In this way, each quantitative measurement cycle is treated as an independent verification and calibration unit. Through successive iterations, the system enables the output of the main measurement loop to converge rapidly and remain within the extremely high accuracy range defined by the weighing reference.

[0056] Example 1

[0057] like Figure 1 As shown, a fluid metering system based on dual-path coordination and real-time feedback mainly includes the following components:

[0058] Raw material tank 1: Used to store the fluid to be measured.

[0059] Metering pump 3: As the power source and initial metering unit of the system, it is used to accurately extract and transport fluids. Its type can be a plunger pump, peristaltic pump, gear pump, etc.

[0060] Flow meter 4: Installed downstream of metering pump 3, it is used to monitor and provide feedback on the flow rate or cumulative flow of the fluid flowing through it in real time. Its type can be a mass flow meter, electromagnetic flow meter, vortex flow meter, etc.

[0061] Shut-off valve 5: Serves as a fluid switch, used to promptly shut off fluid from the pipeline into the weighing container 7.

[0062] Weighing container 7: Used to receive fluid from the calibration pipeline and provide a container for it.

[0063] Weighing sensor 6: Located below the weighing container 7, it is used to measure the total mass of the weighing container 7 and the fluid inside it with high precision, and to obtain the net weight of the fluid through a tare operation. Its measurement result serves as the benchmark for metrological accuracy.

[0064] Control unit 9: This is the "brain" of the system, typically implemented by a PLC, industrial computer, or embedded controller. It connects via signal lines to metering pump 3, flow meter 4, shut-off valve 5, and load cell 6, and is used for:

[0065] Send start / stop and speed control signals to metering pump 3.

[0066] Receive the flow signal from flow meter 4.

[0067] Send a shut-off command to shut-off valve 5.

[0068] Receive weight signal from weighing sensor 6.

[0069] implement Figure 2 The control logic shown performs data comparison, error calculation, and parameter correction.

[0070] Example 2

[0071] like Figure 2 As shown, the high-precision fluid measurement method of the present invention specifically includes the following steps:

[0072] S201: Start. The system powers on and starts up.

[0073] S202: System initialization. Control unit 9 loads preset parameters, including: the quantitative value of a single measurement (Qset), the initial value of the correction coefficient (usually set to K=1), and other parameters required for system operation.

[0074] S203: Start the main metering circuit. Control unit 9 first ensures that shut-off valve 5 is in the position leading to weighing container 7 (calibration position). Then, it starts metering pump 3 and monitors the reading of flow meter 4 with the current calibration factor K.

[0075] S204: Determine if the flow meter reading has reached the quantitative value. Control unit 9 continuously determines the condition: Flow meter cumulative reading × correction coefficient K >= quantitative value Qset? If not reached ("No"), continue metering. If reached ("Yes"), proceed to the next step.

[0076] S205: Stop the pump and isolate the weighing container. The control unit 9 immediately stops the metering pump 3 and can ensure that the weighing container 7 is fluidly isolated by closing the shut-off valve 5 for stable weighing.

[0077] S206: Weigh and record the actual mass value (Wactual). After the fluid stabilizes, the control unit 9 reads the actual mass value (Wactual) of the fluid in the weighing container 7 from the weighing sensor 6.

[0078] S207: Calculate the new correction factor (Knew). Control unit 9 calculates the new correction factor for the next measurement according to the formula Knew=Wactual / Qset.

[0079] S208: Update system correction coefficients. The system updates the currently used correction coefficient K to the newly calculated Knew, i.e., executes K=Knew.

[0080] S209: Empty the weighing container and zero it. The control unit 9 controls the opening of the discharge valve 8 or the discharge of fluid from the weighing container 7, and performs a zeroing operation on the weighing platform to prepare for the next metering cycle.

[0081] S210: Prepare for the next measurement. The process returns to step S203 to begin a new measurement cycle. In the new cycle, the system will use the newly updated correction factor K for more accurate measurements.

[0082] Specific implementation methods:

[0083] Initialization: The operator sets the single-measurement quantitative value Qset=10.000kg in the control unit, and the initial value of the system correction coefficient K=1.000.

[0084] Start the first loop:

[0085] The control unit starts the metering pump and monitors the flow meter with K=1.000 as the current coefficient.

[0086] When the cumulative flow meter reading × 1.000 = 10.000 kg, immediately stop the metering pump and switch the valve to isolate the weighing container.

[0087] First verification:

[0088] The weighing sensor measured the actual mass as W1 = 10.015 kg.

[0089] Calculation error: E1 = (10.000 - 10.015) / 10.015 × 1000 ≈ -1.5‰

[0090] Calculate the new correction factor: Knew = 10.015 / 10.000 = 1.0015

[0091] First correction: The system updates coefficient K to 1.0015 for the next measurement.

[0092] Start the second cycle:

[0093] After emptying and zeroing the weighing container, the second measurement begins.

[0094] This time, the control system uses a new coefficient, which stops the pump when the initial cumulative reading of the flow meter × 1.0015 = 10.000 kg. This means that when the initial reading of the flow meter reaches approximately 9.985 kg, the system considers the target to have been reached.

[0095] After stopping, the weight was measured to be W2 = 9.998 kg.

[0096] Second verification and correction:

[0097] Error: E2=(10.000-9.998) / 9.998×1000≈0.2‰ (already within 2‰).

[0098] Calculate the new coefficient Knew = 9.998 / 10.000 = 0.9998.

[0099] Continuous operation: This process repeats continuously. The metering of each batch is directly corrected by the calibration results of the previous batch, thereby effectively compensating for the effects of changes in fluid temperature and viscosity or micro-drifts in pump and valve performance, achieving continuous high-precision output.

Claims

1. A fluid metering system based on two-way collaboration and real-time feedback, characterized in that, The application relates to a fluid metering system, comprising: a main metering loop comprising a metering pump and a flow meter connected in sequence, for continuously metering and controlling the delivery of fluid; a verification metering loop comprising a weighing sensor and a weighing container placed thereon, for receiving and weighing the fluid discharged from the main metering loop; a fluid pipeline and valve system for selectively guiding the fluid to the weighing container or a downstream outlet; a control system in communication with the metering pump, the flow meter and the weighing sensor; the control system is configured to perform the following steps: 1) controlling the main metering loop to deliver a preset amount of fluid to the weighing container; 2) stopping the delivery of fluid when the cumulative measurement value of the flow meter reaches the amount; 3) obtaining the actual mass value of the fluid in the weighing container through the weighing sensor; 4) calculating a correction coefficient according to the amount and the actual mass value; 5) applying the correction coefficient to the metering control of the next amount of fluid.

2. A fluid metering system based on two-way collaboration and real-time feedback as claimed in claim 1, wherein, The control system calculates the correction coefficient according to the amount and the actual mass value in the following manner: dividing the actual mass value by the amount to obtain a proportional coefficient as the correction coefficient.

3. The fluid metering system based on dual path synergy and real-time feedback of claim 1, wherein, The control system is configured to work in a cyclic manner, and each cycle includes one-time amount delivery, one-time weighing verification, one-time coefficient calculation and application, and the correction coefficient calculated in the current cycle is immediately applied to the metering control in the next cycle.

4. The fluid metering system based on dual path synergy and real-time feedback of claim 1, wherein, The specific manner of applying the correction coefficient to the metering control is: using the correction coefficient to correct the reading of the flow meter, and the corrected flow value is equal to the original reading of the flow meter multiplied by the correction coefficient; the control system judges whether the amount is reached based on the corrected flow value.

5. The fluid metering system based on dual path synergy and real-time feedback of claim 1, wherein, The specific manner of applying the correction coefficient to the metering control is: using the correction coefficient to correct the control parameter of the metering pump, so that the ratio of the actual output of the metering pump to the theoretical output approaches the correction coefficient.

6. A fluid metering system based on dual path synergy and real-time feedback as claimed in claim 1, wherein, The valve system comprises a three-way switching valve; one inlet of the three-way switching valve is connected to the output end of the main metering loop, and the two outlets of the three-way switching valve are connected to the inlet of the weighing container and the downstream outlet, respectively.

7. The fluid metering system based on dual path synergy and real-time feedback of claim 1, wherein, The control system is further configured to control the emptying of the weighing container and the zeroing of the weighing sensor after each weighing verification is completed, to prepare for the next metering verification cycle.

8. A method of fluid metering based on the fluid metering system of any one of claims 1 to 7, characterized in that, The application further discloses a metering method, comprising the following steps: S1: setting an amount Qset for single metering; S2: starting the main metering loop to control the metering pump to deliver fluid to the weighing container; S3: monitoring the cumulative flow Qall through the flow meter, and stopping the delivery when the monitoring value reaches the amount; S4: weighing the actual mass Wactual of the fluid in the weighing container through the weighing sensor; S5: calculating a correction coefficient k according to the amount and the actual mass value; S6: applying the correction coefficient to the control of the next metering cycle; S7: emptying the weighing container and zeroing, and repeating steps S2 to S6 to perform the next metering cycle.

9. A method of fluid metering as claimed in claim 8, wherein, In step S5, the correction coefficient K is calculated by the formula: K=Wactual / Qset, wherein Wactual is the actual mass value and Qset is the amount.

10. A method of fluid metering as defined in claim 8, wherein, In step S6, applying the correction coefficient includes multiplying the reading of the flow meter by the correction coefficient K in the next metering cycle, and using the product as the basis for determining whether the dosing value has been reached.

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