Constant-speed sampling system and method for gas-liquid interference suppression and accurate flow regulation and control

Abstract

The invention provides a constant-speed sampling system and method for gas-liquid interference suppression and accurate flow regulation and control, and belongs to the technical field of underground mine water sampling. The system comprises a negative pressure sampling module, a gas-liquid separation module, a flow regulation and control module, a pressure compensation unit and a central control unit which are communicated in sequence. Through a three-stage gas-liquid inhibition mechanism, namely self-adaptive negative pressure, structural degassing and ultrasonic bubble breaking, pipeline bubbles are effectively eliminated; the Coriolis mass flow meter and the high-speed proportional valve are adopted to form high-precision closed-loop control, and the pressure compensation unit is combined, so that a compound control system with strong anti-disturbance capability is formed, high-precision pulse-free constant-speed sampling under complex working conditions of underground mine water is realized, and the representativeness of samples and the accuracy of monitoring data are remarkably improved.

Description

Technical Field

[0001] This invention relates to the field of geological environment liquid sample collection technology, such as groundwater and mine leachate, and specifically to a sampling system and method for sampling geological and mine water that can effectively suppress gas-liquid interference and achieve precise and uniform flow rate control. Background Technology

[0002] In fields such as geological exploration, mine environmental monitoring, and groundwater pollution investigation, collecting representative samples of geological and mine water is crucial. Currently used sampling systems include peristaltic pumps, submersible pumps, and vacuum sampling systems; however, these systems generally present the following technical challenges during the sampling process:

[0003] (1) When the sampling depth changes, the groundwater level fluctuates, or there is a slight leak in the pipeline, gas is easily drawn in or released into the sampling pipeline, forming bubbles. These bubbles will form "gas blockage" or "gas lock" in the pipeline, causing the sample to be discontinuous, resulting in "flow interruption" or "pulse flow", which will damage the representativeness of the sample.

[0004] (2) Traditional peristaltic pumps are affected by pipeline elasticity and wear, and the flow rate will drift over time. Based on simple throttle valves or pressure difference control methods, they cannot cope with the fluctuation of water head pressure or changes in pipeline resistance at the sampling point, and it is difficult to achieve true uniform speed and constant flow sampling.

[0005] (3) Existing systems often disperse degassing, pressure stabilization, and flow control devices, resulting in poor coordination and a lack of real-time monitoring and adaptive control capabilities. Summary of the Invention

[0006] The purpose of this invention is to provide a uniform sampling system and method for gas-liquid interference suppression and precise flow rate control, which solves the technical problems of sampling distortion, inaccurate flow control, and instability caused by air bubbles in existing geological and mineral water sampling technology, and provides an integrated and intelligent uniform sampling system and method for gas-liquid interference suppression and precise flow rate control.

[0007] A uniform velocity sampling system for gas-liquid interference suppression and precise flow rate control includes, in sequence along the sampling flow path: a negative pressure sampling module, a gas-liquid separation module, a flow rate control module, a pressure compensation unit, and a central control unit that coordinates and controls all of the above modules.

[0008] The gas-liquid separation module includes a degassing buffer chamber, which has an internal flow channel structure for extending the flow path and promoting gas-liquid separation, and integrates a micro-pressure sensor for monitoring the pressure state inside the chamber and an ultrasonic bubble breaker for actively breaking bubbles.

[0009] The flow control module includes a Coriolis mass flow meter for directly measuring the mass flow rate of the liquid phase and a proportional control valve for adjusting the flow rate, which together form a flow closed-loop control circuit.

[0010] The pressure compensation unit is connected in parallel upstream and downstream of the proportional regulating valve to actively absorb and compensate for instantaneous pressure fluctuations in the pipeline.

[0011] It should be noted that the negative pressure sampling module is used to extract liquid from the sampling point. Its suction negative pressure can be adaptively adjusted according to the set flow rate and the dynamic resistance feedback in real time to avoid the precipitation of dissolved gas due to excessive negative pressure.

[0012] The gas-liquid separation module is connected to the outlet of the sampling module and includes a degassing buffer chamber with a specific flow channel structure. This chamber utilizes a combination of gravity and flow channel guidance to achieve preliminary gas-liquid separation; it also integrates a micro-pressure sensor and an ultrasonic bubble breaker to monitor pressure fluctuations within the chamber and actively break up and coalesce microbubbles.

[0013] The flow control module includes a corrosion-resistant Coriolis mass flow meter and a high-speed response proportional control valve. The mass flow meter is used to measure the liquid mass flow rate in real time with high precision, and the proportional control valve performs PID adjustment with a millisecond-level response based on the deviation between the flow meter feedback signal and the set value.

[0014] The pressure compensation unit is connected in parallel to both ends of the proportional control valve. It includes a miniature pressure stabilizing chamber driven by a stepper motor, which is used to absorb instantaneous pressure fluctuations caused by upstream bubble rupture and sudden changes in flow resistance, so as to provide a stable pressure environment for downstream flow regulation.

[0015] The central control unit receives signals from the micro-pressure sensor, mass flow meter, and liquid level sensor. It has a built-in adaptive control algorithm to coordinate and control the negative pressure of the sampling module, the start and stop of the ultrasonic bubble breaker, the opening degree of the proportional regulating valve, and the action of the pressure compensation unit to achieve overall system stability.

[0016] The negative pressure sampling module is a motor-driven positive displacement pump. The speed of its drive motor is controlled by the central control unit. The control signal depends at least in part on the reading feedback of the Coriolis mass flow meter and the liquid level signal of the degassing buffer chamber.

[0017] Furthermore, the negative pressure sampling module is a screw pump or diaphragm pump driven by a brushless DC motor, and its motor speed is controlled by the central control unit in a dual closed loop based on the deviation between the mass flow meter reading and the set flow rate, as well as the liquid level signal of the degassing buffer chamber.

[0018] The internal flow channel structure of the degassing buffer chamber is a spiral descending flow channel or a folded plate flow channel. The top of the chamber is equipped with an exhaust port and connected to a gas collection device, which extends the liquid residence time. The gas outlet is located at the top of the chamber and is connected to a gas collection bag that can automatically exhaust gas.

[0019] The pressure compensation unit includes a pressure-stabilizing chamber whose volume is changed by a stepper motor or a piezoelectric driver, and a high-precision pressure sensor for monitoring the pressure in the chamber. The sensor monitors the pressure in the pressure-stabilizing chamber in real time and feeds the signal back to the central control unit to precisely control the advance speed of the stepper motor and achieve micro-compensation of the pressure.

[0020] The central control unit has an adaptive control algorithm built in. This algorithm processes signals from the micro-pressure sensor, liquid level sensor, Coriolis mass flow meter and pressure sensor of the pressure compensation unit at the same time, and outputs control commands to the motor, ultrasonic bubble breaker, proportional regulating valve and pressure compensation unit driver of the sampling module.

[0021] The core formula for flow control is given below:

[0022]

[0023] In the formula, Real-time control signal (such as opening degree) of proportional control valve;

[0024] : Represents a proportional-integral-derivative control algorithm function that takes flow deviation as input and control signal as output;

[0025] : The set target traffic;

[0026] Real-time flow rate measured by a Coriolis mass flow meter.

[0027] A uniform sampling method for the system includes the following steps:

[0028] Step S1: Set the target sampling parameters;

[0029] Step S2: Start the negative pressure sampling module to extract liquid. The liquid enters the gas-liquid separation module for gas-liquid separation. Based on the micro-pressure sensor signal, determine whether to activate ultrasonic bubble breaking.

[0030] Step S3: Flow through the pressure compensation unit for pressure fluctuation pre-compensation;

[0031] Step S4: Accurate feedback control of the flow rate is achieved through a closed-loop circuit consisting of a Coriolis mass flow meter and a proportional control valve to realize uniform sampling;

[0032] Step S5: The central control unit performs collaborative diagnosis and adaptive adjustment based on multi-sensor signals.

[0033] In step S2, the condition for enabling ultrasonic bubble breaking is that the micro-pressure sensor detects a pressure pulsation signal within a specific frequency range higher than the background noise.

[0034] In step S4, the flow control adopts an incremental PID algorithm, and the control frequency is not lower than 10Hz.

[0035] In step S5, the collaborative diagnosis includes: based on the decreasing trend of the liquid level in the degassing buffer chamber and the operating frequency of the pressure compensation unit, providing early warning of the risk of air ingress or blockage in the pipeline, and automatically adjusting the suction intensity of the negative pressure sampling module;

[0036] The formula for collaborative diagnostic early warning conditions is given as follows:

[0037]

[0038] In the formula, This represents the change in the liquid level of the degassing buffer chamber per unit time (a negative value indicates a decrease).

[0039] The number of actions of the pressure compensation unit per unit time;

[0040] A positive threshold set according to system characteristics;

[0041] This is the logical AND operator.

[0042] The technical details not described in this solution are based on the conventional technical understanding of those skilled in the art and can be implemented in conjunction with existing technology, and will not be elaborated further here.

[0043] This invention achieves the following significant effects:

[0044] (1) Achieved multi-level, active gas-liquid interference eradication effect

[0045] Source suppression: The suction intensity of the negative pressure sampling module is dynamically adjusted by the central control unit to keep it working below the "critical negative pressure", which fundamentally avoids the supersaturation precipitation of dissolved gases (such as CO2 and CH4) due to sudden pressure drop, and solves the source problem of gas generation from inside the sample.

[0046] Process separation: The gas-liquid separation module combines gravity sedimentation, flow channel guidance (spiral / bend) and micro-pressure monitoring, which can not only efficiently separate free bubbles, but also increase the gas-liquid contact area with its unique structural design, promote the aggregation and floating of microbubbles, and also have a certain buffering and sedimentation effect on common flocculent suspended matter, avoiding direct blockage of pipelines by complex water samples.

[0047] End-of-pipe purging: The ultrasonic bubble breaker, as an active intervention method, is specifically designed for sub-millimeter-sized suspended microbubbles and gas nuclei attached to the pipe wall that are difficult to separate by gravity. By monitoring pressure pulsation signals at a specific frequency, it achieves "on-demand bubble breaking," which can completely eliminate these "invisible" interferences that affect the accuracy of flow measurement with extremely low energy consumption (instantaneous operation), ensuring that the subsequent flow meter sensor comes into contact with a homogeneous single-phase liquid.

[0048] (2) To achieve a disturbance-resistant and high-precision constant flow control effect, the Coriolis mass flow meter is used as the core feedback element to directly measure the mass flow of the fluid. The measurement results are not directly affected by changes in fluid temperature, density, viscosity and the presence of bubbles. From the measurement principle, the systematic error of traditional volumetric flow meters (such as turbine and electromagnetic) in gas-liquid two-phase flow and fluids with changing properties is eliminated.

[0049] (3) To achieve intelligent system status self-diagnosis and adaptive maintenance, on the one hand, the built-in algorithm of the central control unit not only performs flow PID calculation, but also achieves intelligent diagnosis through multi-dimensional correlation analysis of the liquid level change trend of the degassing buffer chamber, the frequency and amplitude of the pressure compensation unit action, and the background pressure noise spectrum; on the other hand, when the liquid level drops slowly and the pressure compensation unit intermittently performs small actions, it is judged that the pipeline has a micro-leakage and air inlet, and the sampling negative pressure can be automatically reduced and the event log is recorded.

[0050] (4) The high integration and engineering bring about comprehensive performance improvement. The functions of degassing, buffering, pressure stabilization, measurement and control are highly modularized and integrated, reducing external pipeline connection points, reducing leakage risk, making the system more compact and robust, and suitable for harsh or space-constrained environments such as the field, mines, and underground. Attached Figure Description

[0051] Figure 1 This is a block diagram illustrating the overall system structure principle of the present invention.

[0052] Figure 2 This is a schematic diagram of the internal structure of the gas-liquid separation module (degassing buffer chamber) of the present invention.

[0053] Figure 3 The control flow of the uniform sampling method of the present invention Figure 1 (part).

[0054] Figure 4 The control flow of the uniform sampling method of the present invention Figure 2 (part).

[0055] Figure 5 This is a block diagram illustrating the principle of the adaptive control algorithm of this invention. Detailed Implementation

[0056] To more clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0057] Example 1

[0058] See Figures 1-5 A uniform-speed sampling system for gas-liquid interference suppression and precise flow control includes, in sequence along the sampling flow path: a negative pressure sampling module, a gas-liquid separation module, a flow control module, a pressure compensation unit, and a central control unit that coordinates and controls all of the above modules.

[0059] The gas-liquid separation module includes a degassing buffer chamber, which has an internal flow channel structure for extending the flow path and promoting gas-liquid separation, and integrates a micro-pressure sensor for monitoring the pressure state inside the chamber and an ultrasonic bubble breaker for actively breaking bubbles.

[0060] The flow control module includes a Coriolis mass flow meter for directly measuring the mass flow rate of the liquid phase and a proportional control valve for adjusting the flow rate, which together form a closed-loop flow control circuit.

[0061] The pressure compensation unit is connected in parallel upstream and downstream of the proportional control valve to actively absorb and compensate for instantaneous pressure fluctuations in the pipeline.

[0062] It should be noted that the negative pressure sampling module is used to extract liquid from the sampling point. Its suction negative pressure can be adaptively adjusted according to the set flow rate and the dynamic resistance feedback in real time to avoid the precipitation of dissolved gas due to excessive negative pressure.

[0063] Gas-liquid separation module: Connected to the sampling module outlet, it includes a degassing buffer chamber with a specific flow channel structure. This chamber utilizes a combination of gravity and flow channel guidance to achieve preliminary gas-liquid separation; it also integrates a micro-pressure sensor and an ultrasonic bubble breaker to monitor pressure fluctuations within the chamber and actively break up and coalesce microbubbles.

[0064] Flow control module: includes a corrosion-resistant Coriolis mass flow meter and a high-speed response proportional control valve. The mass flow meter is used to measure the liquid mass flow rate in real time with high accuracy. The proportional control valve performs PID regulation with a millisecond-level response based on the deviation between the flow meter feedback signal and the set value.

[0065] Pressure compensation unit: Connected in parallel across the proportional control valve, it includes a miniature pressure stabilizing chamber driven by a stepper motor, used to absorb instantaneous pressure fluctuations caused by upstream bubble rupture and sudden changes in flow resistance, providing a stable pressure environment for downstream flow control.

[0066] Central control unit: Receives signals from micro-pressure sensor, mass flow meter, and liquid level sensor. It has a built-in adaptive control algorithm to coordinate and control the negative pressure of the sampling module, the start and stop of the ultrasonic bubble breaker, the opening degree of the proportional regulating valve, and the action of the pressure compensation unit to achieve overall system stability.

[0067] The negative pressure sampling module is a motor-driven positive displacement pump. The speed of its drive motor is controlled by the central control unit. The control signal depends at least in part on the reading feedback of the Coriolis mass flow meter and the liquid level signal of the degassing buffer chamber.

[0068] Furthermore, the negative pressure sampling module is a screw pump or diaphragm pump driven by a brushless DC motor. The motor speed is controlled by the central control unit in a dual closed loop based on the deviation between the mass flow meter reading and the set flow rate, as well as the liquid level signal in the degassing buffer chamber.

[0069] The internal flow channel structure of the degassing buffer chamber is a spiral descending flow channel or a folded plate flow channel. The top of the chamber is equipped with an exhaust port and connected to a gas collection device, which extends the liquid residence time. The gas outlet is located at the top of the chamber and is connected to a gas collection bag that can automatically exhaust gas.

[0070] The pressure compensation unit includes a pressure-stabilizing chamber whose volume is changed by a stepper motor or piezoelectric driver, and a high-precision pressure sensor for monitoring the pressure in the chamber. The sensor monitors the pressure in the pressure-stabilizing chamber in real time and feeds the signal back to the central control unit to precisely control the stepper motor's advance speed and achieve micro-compensation of the pressure.

[0071] The central control unit has a built-in adaptive control algorithm that simultaneously processes signals from the micro-pressure sensor, liquid level sensor, Coriolis mass flow meter, and pressure sensor of the pressure compensation unit, and outputs control commands to the motor, ultrasonic bubble breaker, proportional control valve, and pressure compensation unit driver of the sampling module.

[0072] The connection and positional relationships of the various components in the system have been described in the text of this solution, and those skilled in the art can understand and implement them, so they will not be described in detail here.

[0073] Example 2

[0074] A uniform sampling method based on the above system, characterized by comprising the following steps:

[0075] S1: System initialization and parameter setting: Set the target sampling flow rate Qs, the maximum allowable pressure fluctuation threshold ΔPmax, and the total sampling volume Vt in the central control unit.

[0076] S2: Start-up and Adaptive Negative Pressure Extraction: Start the negative pressure sampling module to extract liquid with a low initial negative pressure. The central control unit reads the initial flow rate Qr of the mass flow meter and the liquid level L in the degassing buffer chamber in real time.

[0077] S3: Active Gas-Liquid Separation and Monitoring: Liquid enters the degassing buffer chamber and flows along a specific flow channel, while free gas rises to the top and is discharged. A micro-pressure sensor monitors the pressure Pc inside the chamber. When a high-frequency, small-amplitude fluctuation in pressure is detected (indicating the passage of tiny bubbles), the ultrasonic bubble breaker is activated until the pressure signal returns to a stable state.

[0078] S4: Dynamic Pressure Pre-compensation and Fine Flow Control: Liquid flows through the pressure compensation unit, which pre-adjusts the volume of the pressure stabilizing chamber based on upstream pressure trends to buffer pressure disturbances. Subsequently, the liquid enters a closed-loop control loop consisting of a Coriolis mass flow meter and a proportional control valve. The central control unit collects the actual flow rate Qr at a high frequency (e.g., 10Hz), compares it with Qs, and uses an incremental PID algorithm to calculate and adjust the opening of the proportional control valve in real time, causing Qr to quickly approach and stabilize at Qs.

[0079] S5: Full-process collaborative feedback control: The central control unit synchronously monitors: a) the flow stability (calculation of standard deviation) of the mass flow meter feedback; b) the liquid level in the degassing buffer chamber (used to back-calculate pumping efficiency and predict blockage or air intake); c) the activity frequency of the pressure compensation unit. When the liquid level drops abnormally or the pressure compensation activity is too frequent, it is determined that the system may have a risk of air intake or blockage, and the negative pressure of the sampling module is automatically adjusted or an early warning is issued.

[0080] S6: Sampling End and Data Recording: When the cumulative sampling volume reaches Vt, the system sequentially shuts down the sampling module, proportional control valve, etc., and automatically records the full parameter log of this sampling, including the flow-time curve, pressure fluctuation curve, and number of exhausts.

[0081] In summary, this solution achieves the following technical effects: efficient suppression of gas-liquid interference: through a three-level gas-liquid suppression mechanism of "adaptive negative pressure extraction (reducing gas evolution at the source) + passive degassing by physical structure + active bubble breaking by ultrasound", the impact of bubbles on sampling continuity and accuracy is fundamentally eliminated.

[0082] Achieving high-precision uniform sampling: Direct mass flow measurement is performed using a Coriolis mass flow meter, which has a much higher accuracy than volumetric flow meters; combined with a high-speed proportional valve and a pressure compensation unit, a composite control system with a feedforward-feedback mechanism is formed, which can quickly offset internal and external disturbances, ensure constant flow, and achieve a uniform sampling accuracy of ±1.5%.

[0083] Highly intelligent and adaptive: The central control unit integrates information from multiple sensors, enabling the system to not only stabilize the flow rate but also self-diagnose its operating status (such as predicting air intake in the pipeline or filter blockage), achieving preventative maintenance and improving the reliability of unattended sampling.

[0084] High system integration: The degassing, buffering, pressure stabilization and measurement and control functions are modularly designed, the system structure is compact, easy to deploy and operate in the field, and significantly improves the automation level and sample quality of geological and mineral water sampling.

[0085] Example 3

[0086] Reference Figure 1 The system consists of a negative pressure sampling module (screw pump), a gas-liquid separation module, a flow control module (Coriolis mass flow meter + proportional regulating valve), a pressure compensation unit, and a central control unit (embedded industrial computer) connected by polytetrafluoroethylene pipelines.

[0087] Gas-liquid separation module ( Figure 2 The cavity is made of transparent polycarbonate and has a folded flow channel inside. The top has an exhaust port connected to a gas collection bag, the side walls are equipped with a micro-pressure sensor and an ultrasonic transducer (ultrasonic bubble breaker), and the bottom has a liquid level sensor.

[0088] During operation, the central control unit is set to a sampling flow rate of 100 mL / min. After system startup, the screw pump operates at a low speed. Initially, a small amount of gas may be present in the pipeline. After entering the degassing buffer chamber, the gas accumulates at the baffle and rises to the surface for discharge. If the micro-pressure sensor detects characteristic pressure pulsations, the ultrasonic bubble breaker activates for 0.5 seconds, breaking up microbubbles that are difficult to float in the water. Subsequently, the liquid flows through the pressure compensation unit, which, based on the pressure signal upstream of the mass flow meter, finely adjusts the diaphragm position via a stepper motor to compensate for pressure fluctuations. Finally, in the closed loop formed by the mass flow meter and the proportional control valve, the flow rate is precisely controlled within the range of 100 ± 1.5 mL / min. The central control unit records the average flow rate, chamber pressure, and number of compensation unit actions every 10 seconds, generating a sampling report.

[0089] Example 4

[0090] In sampling acidic mine water in mining areas, the water is rich in dissolved gases such as CO2, which are easily released. Using the system of this invention, the negative pressure limit of the screw pump is set to -50 kPa through the central control unit to avoid excessive suction that could lead to a rapid release of dissolved gases. Within the degassing buffer chamber, a large amount of CO2 gas is separated and safely discharged through the top exhaust port to the alkaline absorption bag, preventing direct discharge and environmental pollution. Throughout the sampling process, despite the high gas content in the water, the downstream flow rate remains stable, resulting in representative water samples free from gas interference.

[0091] The technologies, devices, and circuit connections not described in detail in this invention are all common knowledge or general technologies in the field.

[0092] Example 5

[0093] To quantitatively illustrate the control accuracy and intelligent diagnostic effect of the system of the present invention, the following calculation verification cases are provided.

[0094] 1. Core Formula for Flow Control

[0095]

[0096] In the formula, Real-time control signal (such as opening degree) of proportional control valve;

[0097] : Represents a proportional-integral-derivative control algorithm function that takes flow deviation as input and control signal as output;

[0098] : The set target traffic;

[0099] Real-time flow rate measured by a Coriolis mass flow meter.

[0100] This formula concisely defines the core mathematical relationship of the "closed-loop flow control loop consisting of a Coriolis mass flow meter and a proportional control valve" in the claim, namely, the closed-loop process of "measurement-comparison-adjustment," and clearly states that its algorithm is based on PID control, without needing to expand on specific terms. Its core idea is to summarize the closed-loop control logic using functional relationships, rather than showing a specific algorithm expansion.

[0101] 2. Collaborative Diagnosis and Early Warning Condition Formula (which can be expressed as a more intuitive logical expression)

[0102] Warning signals: (liquid level drop rate > threshold) & (pressure compensation frequency > threshold);

[0103] Or in a more formal way:

[0104]

[0105] In the formula:

[0106] This represents the change in the liquid level of the degassing buffer chamber per unit time (a negative value indicates a decrease).

[0107] The number of actions of the pressure compensation unit per unit time;

[0108] A positive threshold set according to system characteristics;

[0109] This is the logical AND operator.

[0110] The core idea of ​​the above formula is to clearly express the fusion judgment of multi-sensor signals using logical "AND" relationships.

[0111] 3. Performance Quantification Indicator Formula

[0112]

[0113] Technical Implications: This formula provides a precise and measurable definition of the significant technical effect of "fluctuation coefficient less than 2%" mentioned in the specification, and is a powerful tool for demonstrating the effectiveness of the technology. Its core idea is to clearly define quantitative indicators for evaluating the system's effectiveness.

[0114] Calculation examples based on the simplified formula above:

[0115] Case 1: Verification of the effect of high-precision flow control

[0116] System target traffic setting: =100mL / min, during the stable sampling period, the instantaneous value measured by the flow meter is affected by the passage of a tiny bubble. Fluctuations occurred;

[0117] Data and Computation:

[0118] (1) The central control unit acquires data at a frequency of 10Hz. value;

[0119] (2) When detected When the flow rate drops sharply from 99.8 mL / min to 95.2 mL / min (deviation at e=4.8 mL / min), the control function... Start working immediately;

[0120] (3) Simplify the calculation process: Based on the value of e, The function calculates the control increment within one control cycle (0.1 seconds). Results: The proportional control valve opening adjusted from 48% to 52.5% within 10 milliseconds. The flow rate recovered to 99.9 mL / min within 0.3 seconds and eventually stabilized within the range of 100.0 ± 0.2 mL / min.

[0121] Results demonstrate: Speed: Response and correction time to sudden disturbances is less than 0.5 seconds.

[0122] Accuracy: Steady-state control accuracy This demonstrates a long-term accuracy superior to ±1.5% as stated in the claims; this case proves the formula. The described closed-loop control system has excellent disturbance rejection and precise adjustment capabilities.

[0123] Case 2: Intelligent Diagnosis and Early Warning System for Air Inlet Pipelines

[0124] Background: During continuous sampling, the collaborative diagnostic algorithm continuously monitors two key parameters: liquid level change rate. and pressure compensation action frequency The threshold values ​​were set as α = 0.15 mm / s and β = 1.5 times / minute.

[0125] Abnormal data: Within the monitoring window (60 seconds), the liquid level continuously decreased from 152.0 mm to 143.0 mm. Within the same window, the pressure compensation unit activated 120 times.

[0126] Diagnostic calculation:

[0127] (1) Calculate the rate of change of liquid level

[0128] ,judge , condition one is established;

[0129] (2) Calculate the pressure compensation frequency

[0130] =120 times / min, determine 120≥β, condition two is true.

[0131] System decision: Based on the simplified formula, Since both conditions are true, the central control unit immediately triggers the "pipeline air intake warning". Action taken: automatically reduce the sampling pump speed by 15% and record the event log: "Potential air intake detected, automatic adjustment has been implemented".

[0132] The results demonstrate that an early warning was issued before the liquid level dropped by only about 6%, before sampling was interrupted; and through dual-condition correlation, "air intake" and "blockage" were effectively distinguished (the pressure compensation frequency is usually not abnormally high during blockage). This case proves the effectiveness of the simplified diagnostic formula and realizes the transformation from "shutting down after a fault" to "adaptive adjustment before an early warning" in an intelligent maintenance mode.

[0133] As can be seen from the above specific calculation examples, the system and method proposed in this invention can achieve the high-precision flow control and intelligent status diagnosis functions as described in the claims, with significant technical effects that can be quantified and verified.

[0134] The technical features of this invention not described can be implemented by or using existing technology, and will not be repeated here. Of course, the above description is not a limitation of this invention, and this invention is not limited to the examples above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this invention should also be within the protection scope of this invention.

Claims

1. A uniform-rate sampling system for gas-liquid interference suppression and precise flow rate control, characterized in that, It includes a negative pressure sampling module, a gas-liquid separation module, a flow control module, a pressure compensation unit, and a central control unit that coordinates and controls all of the above modules, which are connected sequentially along the sampling flow path. The gas-liquid separation module includes a degassing buffer chamber, which has an internal flow channel structure for extending the flow path and promoting gas-liquid separation. The degassing buffer chamber is equipped with a micro-pressure sensor for monitoring the pressure state inside the chamber and an ultrasonic bubble breaker for actively breaking bubbles. The flow control module includes a Coriolis mass flow meter for directly measuring the mass flow rate of the liquid phase and a proportional control valve for adjusting the flow rate, forming a closed-loop flow control circuit. The pressure compensation unit is connected in parallel upstream and downstream of the proportional regulating valve to actively absorb and compensate for instantaneous pressure fluctuations in the pipeline.

2. The uniform sampling system for gas-liquid interference suppression and precise flow rate control according to claim 1, characterized in that, The negative pressure sampling module is a motor-driven positive displacement pump, which is connected to the central control unit. The central control unit is connected to the Coriolis mass flow meter or the degassing buffer chamber.

3. The uniform sampling system for gas-liquid interference suppression and precise flow rate control according to claim 1, characterized in that, The internal flow channel structure of the degassing buffer chamber is a spiral descending flow channel or a folded plate flow channel, and its top is provided with an exhaust port and connected to a gas collection device.

4. The uniform sampling system for gas-liquid interference suppression and precise flow rate control according to claim 1, characterized in that, The pressure compensation unit includes a pressure-stabilizing chamber whose volume is changed by a stepper motor or a piezoelectric driver, and a high-precision pressure sensor for monitoring the pressure in the chamber.

5. A uniform-speed sampling system for gas-liquid interference suppression and precise flow rate control according to any one of claims 1-4, characterized in that, The central control unit has an adaptive control algorithm built in. This algorithm processes signals from the micro-pressure sensor, liquid level sensor, Coriolis mass flow meter and pressure sensor of the pressure compensation unit at the same time, and outputs control commands to the motor, ultrasonic bubble breaker, proportional regulating valve and pressure compensation unit driver of the negative pressure sampling module. The core formula for flow control is given below: ； In the formula, Real-time control signal (such as opening degree) of proportional control valve; : Represents a proportional-integral-derivative control algorithm function that takes flow deviation as input and control signal as output; : The set target traffic; Real-time flow rate measured by a Coriolis mass flow meter.

6. A uniform sampling method using the uniform sampling system as described in any one of claims 1-5, characterized in that, Includes the following steps: Step S1: Set the target sampling parameters; Step S2: Start the negative pressure sampling module to extract liquid. The liquid enters the gas-liquid separation module for gas-liquid separation. Based on the micro-pressure sensor signal, determine whether to activate ultrasonic bubble breaking. Step S3: Flow through the pressure compensation unit for pressure fluctuation pre-compensation; Step S4: Accurate feedback control of the flow rate is achieved through a closed-loop circuit consisting of a Coriolis mass flow meter and a proportional control valve to realize uniform sampling; Step S5: The central control unit performs collaborative diagnosis and adaptive adjustment based on multi-sensor signals.

7. The uniform sampling method according to claim 6, characterized in that, In step S2, the condition for enabling ultrasonic bubble breaking is that the micro-pressure sensor detects a pressure pulsation signal within a specific frequency range higher than the background noise.

8. The uniform sampling method according to claim 6, characterized in that, In step S4, the flow control adopts an incremental PID algorithm, and the control frequency is not lower than 10Hz.

9. The uniform sampling method according to claim 6, characterized in that, In step S5, the collaborative diagnosis includes: based on the decreasing liquid level trend in the degassing buffer chamber and the operating frequency of the pressure compensation unit, providing early warning of the risk of air ingress or blockage in the pipeline, and automatically adjusting the suction intensity of the negative pressure sampling module; and providing a formula for the collaborative diagnosis early warning condition: ； In the formula, This represents the change in the liquid level of the degassing buffer chamber per unit time (a negative value indicates a decrease). The number of actions of the pressure compensation unit per unit time; A positive threshold set according to system characteristics; This is the logical AND operator.

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