CN-121994544-A - Uniform sampling system and method for gas-liquid interference suppression and flow precise regulation

Abstract

The invention provides a uniform sampling system and a uniform sampling method for gas-liquid interference suppression and accurate flow regulation, and belongs to the technical field of ground mineral 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 sequentially communicated. The invention effectively eliminates pipeline bubbles through a three-level gas-liquid inhibition mechanism, namely self-adaptive negative pressure, structural degassing and ultrasonic bubble breaking, adopts a Coriolis mass flowmeter and a high-speed ratio example valve to form high-precision closed-loop control, combines a pressure compensation unit to form a composite control system with strong disturbance resistance, realizes high-precision and pulse-free uniform sampling under the complex working condition of ground and mineral water, and remarkably improves the representativeness of samples and the accuracy of monitoring data.

Inventors

• GENG FUQIANG
• Rong Qingchun
• LV MINGHUI
• YANG GUANG
• SUN SHUHAI
• MA WANQI
• WANG BO
• LI JING
• ZHANG RUOXI
• WANG GANG

Assignees

• 山东省地矿工程勘察院(山东省地质矿产勘查开发局八〇一水文地质工程地质大队)

Dates

Publication Date

20260508

Application Date

20260211

Claims (9)

1. 1. The uniform sampling system is characterized by comprising a negative pressure sampling module, a gas-liquid separation module, a flow regulation module, a pressure compensation unit and a central control unit for coordinately controlling all the modules, wherein the negative pressure sampling module, the gas-liquid separation module, the flow regulation module and the pressure compensation unit are sequentially communicated along a sampling flow path; The gas-liquid separation module comprises a degassing buffer cavity, an internal flow channel structure for prolonging a flow path and promoting gas-liquid separation is arranged in the degassing buffer cavity, and a micro-pressure sensor for monitoring the pressure state in the cavity and an ultrasonic bubble breaker for actively breaking bubbles are arranged in the degassing buffer cavity; The flow regulation module comprises a Coriolis mass flowmeter for directly measuring the mass flow of the liquid phase and a proportional regulating valve for regulating the flow, and forms a flow closed-loop control circuit; The pressure compensation unit is connected in parallel with the upstream and downstream of the proportional regulating valve and is used for actively absorbing and compensating instantaneous pressure fluctuation in the pipeline.
2. 2. The uniform sampling system for gas-liquid interference suppression and flow precise regulation and control according to claim 1, wherein the negative pressure sampling module is a motor-driven positive displacement pump, the positive displacement pump is in control connection with the central control unit, and the central control unit is connected with the coriolis mass flowmeter or the degassing buffer cavity.
3. 3. The uniform sampling system for gas-liquid interference suppression and flow precise regulation and control according to claim 1, wherein the internal flow passage structure of the degassing buffer cavity is a spiral descending flow passage or a folded plate flow passage, and the top of the degassing buffer cavity is provided with an exhaust port and is connected with a gas collecting device.
4. 4. The uniform sampling system for gas-liquid interference suppression and flow precise regulation according to claim 1, wherein the pressure compensation unit comprises a pressure stabilizing chamber with volume change driven by a stepping motor or a piezoelectric driver and a high-precision pressure sensor for monitoring the pressure of the chamber.
5. 5. The uniform sampling system for gas-liquid interference suppression and flow precise regulation according to any one of claims 1-4, wherein the central control unit is internally provided with an adaptive control algorithm, the algorithm processes signals from a micro-pressure sensor, a liquid level sensor, a coriolis mass flowmeter and a pressure compensation unit pressure sensor simultaneously and outputs control instructions to a motor of the negative pressure sampling module, an ultrasonic foam breaker, a proportional control valve and a driver of the pressure compensation unit, and a flow control core formula is given: ; in the formula, Real-time control signals (such as opening degree) of the proportional control valve; representing a proportional-integral-derivative control algorithm function taking flow deviation as input and a control signal as output; Setting target flow; real-time flow measured by the Coriolis mass flowmeter.
6. 6. A constant velocity sampling method using the constant velocity sampling system according to any one of claims 1 to 5, comprising the steps of: step S1, setting target sampling parameters; Step S2, starting a negative pressure sampling module to extract liquid, enabling the liquid to enter a gas-liquid separation module to perform gas-liquid separation, and judging whether to start ultrasonic bubble breaking or not based on a micro-pressure sensor signal; S3, performing pressure fluctuation pre-compensation through a pressure compensation unit; S4, carrying out accurate feedback control on flow through a closed loop formed by the Coriolis mass flowmeter and the proportional regulating valve to realize uniform sampling; and S5, the central control unit performs collaborative diagnosis and self-adaptive adjustment based on the multi-sensor signals.
7. 7. The method according to claim 6, wherein in step S2, the condition for starting ultrasonic bubble breaking is that the micro pressure sensor detects a pressure pulsation signal in a specific frequency range higher than background noise.
8. 8. The constant velocity sampling method according to claim 6, wherein in step S4, the flow rate control is performed by an incremental PID algorithm, and the control frequency is not lower than 10Hz.
9. 9. The constant velocity sampling method according to claim 6, wherein in step S5, the collaborative diagnosis includes pre-warning the risk of air intake or blockage of the pipeline and automatically adjusting the suction intensity of the negative pressure sampling module according to the liquid level decreasing trend of the degassing buffer chamber and the action frequency of the pressure compensation unit, and providing a collaborative diagnosis pre-warning condition formula: ; in the formula, For the change in degassing buffer chamber level per unit time (negative values represent a drop); The number of actions of the pressure compensation unit in unit time is set; A positive threshold value set according to the system characteristics; is a logical and operator.

Description

Uniform sampling system and method for gas-liquid interference suppression and flow precise regulation Technical Field The invention relates to the technical field of liquid sample collection in geological environments such as underground water and mining area percolate, in particular to a sampling system and a sampling method for sampling underground water, which can effectively inhibit gas-liquid interference and realize accurate and uniform-speed flow regulation. Background In the fields of geological exploration, mine environment monitoring, groundwater pollution investigation and the like, it is important to collect representative ground mineral water samples. Peristaltic pumps, submersible pumps or vacuum sampling systems commonly used at present, however, the following technical problems generally exist in the sampling process: (1) When the sampling depth changes, the underground water level fluctuates or the pipeline has slight leakage, the gas is easily inhaled or separated out from the sampling pipeline to form bubbles, and the bubbles can form 'air resistance' or 'air lock' in the pipeline, so that the sample is discontinuous, and 'flow break' or 'pulse flow' appears to destroy the sample representativeness; (2) The traditional peristaltic pump is influenced by the elasticity and abrasion of a pipeline, the flow rate can drift along with time, the pressure fluctuation or the pipeline resistance change of a sampling point water head cannot be dealt with based on a simple throttle valve or a pressure difference control mode, and uniform-speed and constant-current sampling in the true sense is difficult to realize; (3) The existing system is often distributed with devices such as degassing, pressure stabilizing and flow control, has poor synergy and lacks the capability of real-time monitoring and self-adaptive regulation and control. Disclosure of Invention The invention aims to provide a uniform sampling system and a uniform sampling method for gas-liquid interference suppression and flow precise regulation, which solve the technical problems of sampling distortion, inaccurate flow control and instability caused by bubbles in the existing mineral water sampling technology and provide an integrated and intelligent system and a method for gas-liquid interference suppression and flow precise regulation uniform sampling. A uniform sampling system for gas-liquid interference suppression and flow precise regulation comprises a negative pressure sampling module, a gas-liquid separation module, a flow regulation module, a pressure compensation unit and a central control unit for coordinated control of all the modules, wherein the negative pressure sampling module, the gas-liquid separation module, the flow regulation module and the pressure compensation unit are sequentially communicated along a sampling flow path; The gas-liquid separation module comprises a degassing buffer cavity, an internal flow channel structure for prolonging a flow path and promoting gas-liquid separation is arranged in the degassing buffer cavity, and a micro-pressure sensor for monitoring the pressure state in the cavity and an ultrasonic bubble breaker for actively breaking bubbles are integrated; the flow regulation and control module comprises a Coriolis mass flowmeter for directly measuring the mass flow of a liquid phase and a proportional regulating valve for regulating the flow, and the Coriolis mass flowmeter and the proportional regulating valve form a flow closed-loop control circuit; The pressure compensation unit is connected in parallel with the upstream and downstream of the proportional regulating valve and is used for actively absorbing and compensating instantaneous pressure fluctuation in the pipeline. The negative pressure sampling module is used for extracting liquid from a sampling point, and the suction negative pressure of the negative pressure sampling module can be adaptively adjusted according to the set flow and the dynamic resistance fed back in real time, so that the solution gas is prevented from being separated out due to overlarge negative pressure. The gas-liquid separation module is communicated with the outlet of the sampling module and comprises a degassing buffer cavity with a specific flow passage structure. The cavity combines gravity with flow channel guiding to realize preliminary separation of gas and liquid, and is integrated with a micro-pressure sensor and an ultrasonic bubble breaker for monitoring pressure fluctuation in the cavity and actively breaking up and coalescing micro bubbles. The flow regulating module comprises a corrosion-resistant Coriolis mass flowmeter and a high-speed response proportional regulating valve, wherein the mass flowmeter is used for measuring the liquid phase mass flow in real time and with high precision, and the proportional regulating valve is used for performing millisecond-level response PID regulation according to deviation of a flowmeter feedback