Nitrogen-filling anti-oxidation method for high-pressure self-balancing type seabed sediment sampling bottle

Abstract

The invention discloses a high-pressure self-balancing type seabed sediment sampling bottle nitrogen charging anti-oxidation method, and belongs to the technical field of chemical analysis and material testing, and the method comprises the following steps: obtaining physical characteristic parameters of sediment in a sampling bottle; performing analysis and calculation according to the physical characteristic parameters, and determining initial nitrogen charging control parameters; filling nitrogen into the sampling bottle based on the initial nitrogen filling control parameter, and synchronously monitoring the pressure in the bottle and the pressure of the external environment to form a driving pressure difference; and a preset self-balancing exhaust valve is driven through the driving pressure difference, and residual gas is exhausted. According to the method, the initial nitrogen charging parameter is determined by firstly obtaining the physical characteristic parameters of the sediment, and then the driving pressure difference formed by nitrogen charging is used for driving the self-balancing exhaust valve to exhaust the residual gas, so that personalized, high-efficiency and high-reliability nitrogen charging anti-oxidation treatment can be carried out on different sediment samples.

Description

Technical Field

[0001] This invention relates to the field of chemical analysis and materials testing technology, and in particular to a method for nitrogen-filling anti-oxidation of high-pressure self-balancing seabed sediment sampling bottles. Background Technology

[0002] Currently, high-pressure self-balancing seabed sediment sampling bottles are geological sampling devices used to obtain and maintain in-situ pressure and environmental conditions from deep-sea environments. Seabed sediments, especially samples from special environments such as deep-sea hydrothermal vents and cold seeps, are often rich in chemicals that are extremely sensitive to oxygen. In order to accurately analyze their geochemical characteristics, effective anti-oxidation measures must be taken immediately after the sample leaves the seabed. This is done by filling the sampling bottle with an inert gas such as nitrogen to replace the oxygen, thereby protecting the sample's original chemical state. This is crucial for subsequent scientific research.

[0003] In current technical practices, the nitrogen purging and oxidation prevention of seabed sediment sampling bottles typically employs a relatively fixed, procedural method. Operators often set a general nitrogen flow rate and purging time based on experience, purging and replacing the sample bottle. The venting process also largely relies on manually opening valves or controlling the opening and closing of solenoid valves through simple timers. The entire process is relatively crude, lacking effective perception and feedback on the specific characteristics of the sample and the real-time status of the replacement process.

[0004] However, the aforementioned existing technical solutions have significant drawbacks. Due to the vast differences in the physical properties of seabed sediments, such as porosity and permeability, between different sampling points, using uniform nitrogen filling parameters is difficult to adapt to all situations. This may lead to over-purification of loose samples, wasting nitrogen, or insufficient purification of dense samples, leaving residual oxygen. Furthermore, the lack of effective process monitoring means that operators cannot accurately determine whether gas replacement is complete, often resorting to extending the operation time to ensure effectiveness. This is not only inefficient but also fails to reliably guarantee the thoroughness of the replacement, thus affecting the preservation quality of the samples. Summary of the Invention

[0005] To address the aforementioned issues, this invention provides a high-pressure self-balancing method for nitrogen-filling and oxidation prevention of seabed sediment sampling bottles. This method involves first obtaining the physical characteristics of the sediments to determine the initial nitrogen-filling parameters, and then using the driving pressure difference generated by nitrogen filling to drive the self-balancing exhaust valve to expel residual gas. This approach enables personalized, efficient, and reliable nitrogen-filling and oxidation prevention treatment for different sediment samples.

[0006] The above objectives can be achieved through the following approach:

[0007] A method for nitrogen-filling and anti-oxidation of high-pressure self-balancing seabed sediment sampling bottles includes: acquiring physical characteristic parameters of sediments inside the sampling bottle; analyzing and calculating the physical characteristic parameters to determine initial nitrogen filling control parameters; filling the sampling bottle with nitrogen based on the initial nitrogen filling control parameters, while simultaneously monitoring the pressure inside the bottle and the external environmental pressure to form a driving pressure difference; and using the driving pressure difference to drive a preset self-balancing exhaust valve to discharge residual gas.

[0008] Optionally, the acquisition of physical characteristic parameters of the sediment in the sampling bottle includes: collecting water content data, density data, and particle size distribution data of the sediment through a sensor group integrating a near-infrared spectral probe, an acoustic impedance sensor, and a laser backscattering analyzer; and performing weighted fusion processing on the water content data, the density data, and the particle size distribution data to generate physical characteristic parameters.

[0009] Optionally, the step of analyzing and calculating the initial nitrogen filling control parameters based on the physical characteristic parameters includes: calculating the matching nitrogen flow rate and filling time based on the physical characteristic parameters and the preset nitrogen filling strategy; and combining the nitrogen flow rate and the filling time to generate the initial nitrogen filling control parameters.

[0010] Optionally, the method further includes: real-time monitoring of the gas environment inside the sampling bottle to obtain oxygen concentration data inside the bottle; comparing the oxygen concentration data inside the bottle with a preset oxygen concentration threshold to generate a concentration deviation signal; and dynamically adjusting the initial nitrogen filling control parameters according to the concentration deviation signal to generate adjusted nitrogen filling control parameters.

[0011] Optionally, the step of dynamically adjusting the initial nitrogen filling control parameters according to the concentration deviation signal includes: when the concentration deviation signal indicates that the oxygen concentration data in the bottle is higher than the oxygen concentration threshold, increasing the nitrogen flow rate in the initial nitrogen filling control parameters, and adaptively extending the filling time according to the rate of decrease of the oxygen concentration data in the bottle; combining the adjusted nitrogen flow rate with the extended filling time to generate the adjusted nitrogen filling control parameters.

[0012] Optionally, after using the driving pressure difference to drive the preset self-balancing exhaust valve to discharge the residual gas, the method further includes: collecting the discharged residual gas through a gas analyzer to obtain exhaust gas composition data; analyzing the dynamic change trends of oxygen content and nitrogen content in the exhaust gas composition data to generate a displacement process state vector; and determining whether the displacement process has reached the completion state based on the displacement process state vector.

[0013] Optionally, determining whether the replacement process has reached a completion state based on the replacement process state vector includes: performing feature extraction based on the replacement process state vector to obtain the absolute value of oxygen content and the rate of change of nitrogen content; comparing the absolute value of oxygen content with a preset endpoint setting value to obtain a first comparison result; comparing the rate of change of nitrogen content with a preset stability threshold to obtain a second comparison result; and performing a logical AND operation between the first comparison result and the second comparison result to determine whether the replacement process has reached a completion state.

[0014] Optionally, the method further includes: after determining that the replacement process has reached a completed state based on the replacement process state vector, generating a replacement completion signal; sending the replacement completion signal to a preset nitrogen charging unit and the self-balancing exhaust valve; controlling the nitrogen charging unit to stop charging nitrogen and closing the self-balancing exhaust valve to obtain a completely sealed state.

[0015] Optionally, the method further includes: continuously monitoring the difference between the pressure inside the sampling bottle and the external environmental pressure under the completely sealed state to obtain the internal and external environmental pressure difference; comparing the internal and external environmental pressure difference with a preset stability range to generate a sealing state evaluation result; and triggering an alarm and recording the abnormal event when the sealing state evaluation result indicates that the internal and external environmental pressure difference exceeds the stability range.

[0016] Based on the same inventive concept, this invention also provides a high-pressure self-balancing seabed sediment sampling bottle nitrogen-filling anti-oxidation system. The system includes: a physical characteristic acquisition module for acquiring physical characteristic parameters of the sediment in the sampling bottle; a nitrogen filling parameter determination module for analyzing and calculating based on the physical characteristic parameters to determine initial nitrogen filling control parameters; a driving pressure difference formation module for filling the sampling bottle with nitrogen based on the initial nitrogen filling control parameters and simultaneously monitoring the pressure inside the bottle and the external environmental pressure to form a driving pressure difference; and a self-balancing exhaust drive module for using the driving pressure difference to drive a preset self-balancing exhaust valve to discharge residual gas.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] 1. This invention achieves intelligent and personalized nitrogen filling processes through prior analysis of sediment physical characteristics. Compared to traditional fixed nitrogen filling procedures, this method can scientifically calculate the optimal initial nitrogen filling control parameters based on specific factors such as sediment density, water content, and particle size distribution. This adaptive adjustment based on sample characteristics ensures that the nitrogen filling strategy is highly targeted from the outset, effectively penetrating various complex pore structures while avoiding disturbance to the sample due to excessive flow velocity. Thus, while ensuring replacement efficiency, it maximizes the preservation of the original physical morphology and layered structure of the sediment sample.

[0019] 2. This invention innovatively utilizes the naturally formed internal and external driving pressure difference during nitrogen filling to drive a preset self-balancing exhaust valve, thus forming a highly efficient and reliable automatic exhaust system. This design cleverly links the nitrogen filling and exhaust processes, achieving continuous and stable gas replacement and ensuring that residual oxygen-containing gas can be completely and smoothly discharged. This self-balancing mechanism not only simplifies the equipment structure and control logic, but more importantly, improves the thoroughness of gas replacement, effectively solving the problem of dead zones or incomplete replacement in localized areas that may occur due to poor exhaust in traditional methods.

[0020] 3. This invention significantly improves the accuracy and process monitoring capabilities of anti-oxidation treatment by introducing a multi-feedback closed-loop control system, including real-time oxygen concentration monitoring and exhaust gas composition analysis. It can dynamically adjust nitrogen purging parameters based on the actual deoxygenation effect and accurately determine the replacement endpoint by analyzing the dynamic trends of exhaust gas composition, ensuring that the entire replacement process reliably terminates only after reaching the preset standard. This refined monitoring and adaptive control throughout the entire process means that the final anti-oxidation effect no longer relies on experience or estimation, but is based on real-time, accurate data, providing a solid guarantee for the quality of long-term sample preservation.

[0021] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1This is a schematic flowchart of a high-pressure self-balancing seabed sediment sampling bottle nitrogen-filled anti-oxidation method according to an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of sensor data fusion according to an embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram illustrating the dynamic adjustment of nitrogen filling parameters according to an embodiment of the present invention.

[0026] Figure 4 This is a diagram showing the monitoring and alarm of the internal and external pressure difference in an embodiment of the present invention.

[0027] Figure 5 This is a schematic diagram of a high-pressure self-balancing seabed sediment sampling bottle nitrogen-filled anti-oxidation system according to an embodiment of the present invention. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Reference Figure 1 One embodiment of the present invention proposes a high-pressure self-balancing method for nitrogen-filling and anti-oxidation of seabed sediment sampling bottles. By first obtaining the physical characteristic parameters of the sediment to determine the initial nitrogen filling parameters, and then using the driving pressure difference formed by nitrogen filling to drive the self-balancing exhaust valve to discharge residual gas, it is possible to achieve personalized, efficient and reliable nitrogen filling and anti-oxidation treatment for different sediment samples.

[0030] The method described in this embodiment specifically includes:

[0031] Obtain the physical characteristic parameters of the sediment in the sampling bottle;

[0032] Based on the physical characteristic parameters, the initial nitrogen filling control parameters are determined through analysis and calculation.

[0033] Nitrogen gas is injected into the sampling bottle based on the initial nitrogen filling control parameters, and the pressure inside the bottle and the external environmental pressure are monitored simultaneously to form a driving pressure difference;

[0034] The preset self-balancing exhaust valve is driven by the driving pressure difference to discharge residual gas.

[0035] Specifically, by precisely measuring multi-dimensional physical characteristic parameters of the sediments inside the sampling bottle, such as water content, density, and particle size distribution, the individual differences of the samples are quantitatively characterized. Subsequently, based on these characteristic parameters, the optimal initial nitrogen purging control parameters are calculated, thereby achieving personalized nitrogen purging strategy settings. Next, based on these calculated initial nitrogen purging control parameters, nitrogen is injected into the sampling bottle through a nitrogen source device equipped with a pressure regulator and flow controller. Simultaneously, the pressure inside the bottle and the external environmental pressure need to be continuously monitored to calculate the driving pressure difference in real time. Finally, this driving pressure difference is used to drive a preset self-balancing exhaust valve. When the driving pressure difference reaches the preset opening threshold of the self-balancing exhaust valve, the valve will automatically open, allowing residual gases such as air or captured volatile organic compounds to be effectively discharged from the bottle. The aforementioned self-balancing exhaust valve is a differential pressure-driven, spring-loaded one-way valve. Its core structure includes a valve body, a valve core or valve disc, a precision spring, and an exhaust channel. The valve core is normally closed under the preload of the spring, sealing the exhaust channel. When the pressure difference between the internal pressure of the sampling bottle and the external ambient pressure—that is, when the internal pressure is higher than the external pressure and exceeds the opening threshold set by the spring preload—the internal pressure overcomes the spring preload through the force applied to the bottom of the valve core, opening the valve core and venting the gas. As the gas is expelled, the internal pressure decreases, and the pressure difference decreases accordingly. When the pressure difference decreases below the opening threshold, the spring preload pushes the valve core back to its original position, closing the venting passage, thus achieving a self-balancing function of automatic opening and closing. As residual gas is expelled, the internal pressure gradually decreases. When the pressure difference drops below the threshold, the self-balancing venting valve automatically closes, achieving an efficient gas replacement process.

[0036] Optionally, the acquisition of physical characteristic parameters of the sediment in the sampling bottle includes:

[0037] The water content, density, and particle size distribution data of the sediments were collected using a sensor array that integrates a near-infrared spectral probe, an acoustic impedance sensor, and a laser backscattering analyzer.

[0038] The moisture content data, density data, and particle size distribution data are weighted and fused to generate physical characteristic parameters.

[0039] Specifically, a highly integrated sensor array is first used to perform in-situ, non-destructive measurements on seabed sediments within the sampling bottle to obtain their key physical characteristics. This sensor array is a composite detection unit that integrates a near-infrared spectral probe, an acoustic impedance sensor, and a laser backscattering analyzer. These three components work together to characterize the sediments from different physical dimensions. The near-infrared spectral probe utilizes the characteristic absorption peaks of water molecules in the near-infrared band, analyzing the absorption intensity of the reflected spectrum to obtain the water content data of the sediments. The acoustic impedance sensor emits sound waves of a specific frequency into the sediments, calculating the acoustic impedance of the sediments by measuring the propagation and reflection characteristics of the sound waves in the medium, and thus retrieving their density data. Simultaneously, the laser backscattering analyzer illuminates the sediment sample with a collimated laser beam, analyzing the intensity distribution and angle information of the backscattered light generated by the particles to calculate the particle size distribution data of the sediments, reflecting the distribution of particles of different sizes. After data acquisition, the obtained multi-source heterogeneous data—water content data, density data, and particle size distribution data—are weighted and fused. To ensure consistent processing of data with different physical dimensions, the data are first normalized, mapping them to a unified dimensionless interval. Then, a weighted calculation is performed using the following formula to generate a comprehensive set of physical characteristic parameters. The final physical characteristic parameters are then calculated... ,have:

[0040] ,

[0041] in, , and These are representative values ​​for the normalized moisture content, density, and particle size distribution data, respectively. The normalization operation is performed by comparing the actual measured value with its possible maximum and minimum values. , and These are preset weighting coefficients, summing to 1. Using orthogonal experimental design or multiple regression analysis, nitrogen-filled anti-oxidation tests are conducted on different types of sediment samples to quantify the actual impact of various physical characteristic parameters such as water content, density, particle size distribution, nitrogen replacement efficiency, time required to reach target oxygen concentration, and nitrogen consumption. By analyzing the experimental data, the weighting coefficients reflecting the dominant role of each parameter can be determined. For example, for predominantly sandy and highly permeable sediments, particle size distribution has a significant impact on gas flow; therefore, the weighting coefficients can be set as follows: , , For sediments that are predominantly clayey and have poor permeability, water content and density have a greater impact on pore structure and the difficulty of gas replacement. The weighting coefficients can be set as follows: , , These weights can more accurately reflect the dominant role of different physical properties in the nitrogen filling process, and through iterative optimization, ensure... The value can effectively distinguish the nitrogen-filling response characteristics of different sediments. For example... Figure 2 The diagram shows the data collected by the three sensors mentioned above: normalized values ​​of water content, density, and particle size distribution, as well as the weighted and fused physical characteristic parameters. This overcomes the limitations and errors inherent in single-sensor measurements by generating a comprehensive set of physical characteristic parameters that reflect the permeability, pore structure, and water-holding capacity of sediments through multi-dimensional information complementarity. This parameter provides a reliable quantitative basis for determining initial nitrogen purging control parameters, enabling the nitrogen purging strategy to be adaptively adjusted based on the actual conditions of the sediments, rather than being fixed or solely based on experience. This significantly improves the targeting and efficiency of nitrogen replacement, laying a solid technical foundation for the efficient and thorough removal of oxygen from samples and the preservation of their original chemical state.

[0042] Optionally, the step of analyzing and calculating the initial nitrogen filling control parameters based on the physical characteristic parameters includes:

[0043] Based on the physical characteristic parameters and the preset nitrogen filling strategy, a matching nitrogen flow rate and filling time are obtained.

[0044] The nitrogen flow rate and the charging time are combined to generate initial nitrogen charging control parameters.

[0045] Specifically, after obtaining physical characteristic parameters that comprehensively characterize the properties of seabed sediments, analysis and calculations are performed based on these parameters to determine a set of optimal initial nitrogen filling control parameters. The core of this calculation process is to invoke a pre-defined nitrogen filling strategy. This strategy establishes a quantitative mapping relationship between the physical characteristic parameters and the ideal nitrogen flow rate and filling duration. By constructing hydrodynamic models of sediment pore structure and gas displacement, such as porous media seepage models based on Darcy's law and mass transport equations, computational fluid dynamics methods are used to simulate the permeation and displacement effects of gas in different pore structures under different nitrogen flow rates and filling durations, thereby predicting the nitrogen filling response of sediments with different physical characteristic parameters. The calculation process is achieved through the following functional relationships, yielding the corresponding nitrogen flow rate and filling duration. For calculating the nitrogen flow rate... With filling time ,have:

[0046] ,

[0047] Among them, the function and This represents the core algorithm or query relationship in the preset nitrogen filling strategy, which can be implemented using a table lookup method. For example, when physical characteristic parameters... At that time, corresponding to loose sandy sediments, a setting can be made. , When physical characteristic parameters At that time, corresponding to loam or mixed sediments, a setting can be made. , ;when At that time, corresponding to dense clay sediments, a setting can be made. , For those data points between these known data points The calculated nitrogen flow rate and charging time are then combined to form a binary control vector, namely the initial nitrogen charging control parameters. These initial nitrogen charging control parameters are then transmitted to the nitrogen charging unit to initiate the replacement process. This approach ensures the scientific validity and rationality of nitrogen charging from the initial stage of the replacement process. It guarantees replacement efficiency, avoids incomplete replacement or wasted time due to improper parameters, and effectively protects the original physical structure of the sediment sample, preventing stratification damage or sample disturbance caused by excessive gas flow. This significantly improves the accuracy and reliability of the entire anti-oxidation treatment process.

[0048] Optionally, the method further includes:

[0049] Real-time monitoring of the gas environment inside the sampling bottle to obtain oxygen concentration data inside the bottle;

[0050] The oxygen concentration data inside the bottle is compared with a preset oxygen concentration threshold to generate a concentration deviation signal;

[0051] The initial nitrogen filling control parameters are dynamically adjusted based on the concentration deviation signal to generate the adjusted nitrogen filling control parameters.

[0052] Specifically, a high-precision oxygen sensor pre-installed inside the sampling bottle or in the exhaust pipe continuously monitors the gas environment within the bottle in real time, acquiring oxygen concentration data reflecting the current replacement effect. This oxygen sensor can be electrochemical or optical fluorescence quenching type to ensure accuracy and stability under high pressure. The real-time oxygen concentration data is continuously compared with a preset oxygen concentration threshold. This threshold is determined based on the chemical characteristics of the collected seabed sediment sample's oxygen sensitivity. For samples that are extremely anaerobic or contain highly oxidizable substances such as sulfides, methane hydrates, or related microorganisms, the oxygen concentration threshold is set very low, such as between 0.05% and 0.1%. For samples with slightly lower sensitivity, the oxygen concentration threshold can be appropriately relaxed to 0.1% to 0.5%, where these ranges represent volume percentages. For calculations... Time-concentration deviation signal ,have:

[0053] ,

[0054] in, It is determined by the oxygen sensor at a specific time point. Real-time oxygen concentration data inside the bottle. This is a preset oxygen concentration threshold, a fixed reference value. When A positive value indicates that the oxygen concentration inside the cylinder is still higher than the target threshold, requiring continued or intensified replacement processing. The control system uses the concentration deviation signal at that moment as the core input to dynamically adjust the previously determined initial nitrogen filling control parameters. This adjustment is not a one-time event but continues throughout the entire nitrogen filling process. The control algorithm will correct the instructions of the nitrogen filling unit in real time based on the magnitude of the concentration deviation signal at that moment, generating a set of adjusted nitrogen filling control parameters. For example... Figure 3As shown, during the initial nitrogen filling stage (0-150 seconds), the oxygen concentration inside the bottle dropped sharply from approximately 20.9%, the initial oxygen concentration in the air. This indicates that after the nitrogen filling process started, nitrogen rapidly replaced the original air inside the sampling bottle. The nitrogen flow rate remained stable at 2.0 L / min during this stage. There is a horizontal line at approximately 0.1% in the figure, which represents the preset oxygen concentration threshold of this invention, the upper limit of the target to be achieved for the anti-oxidation treatment. At approximately 150 seconds, the figure shows that the oxygen concentration inside the bottle briefly rebounded after its previous continuous decline, rising from approximately 0.25% to 0.50%. This may be due to the slow release of trapped gas from inside the sediment. In response to the rebound in oxygen concentration, the nitrogen flow rate was increased from 2.0 L / min to 2.5 L / min. After the flow rate was increased, the oxygen concentration began to decrease again, dropping to 0.08% at approximately 300 seconds, below the oxygen concentration threshold of 0.1%. This feedback loop allows the system to autonomously optimize its operation based on the actual deoxygenation effect, ensuring that the preset low-oxygen environment standard is accurately achieved. It effectively compensates for deviations in the initial model predictions and addresses complex situations such as unexpected gas releases that may occur during sediment replacement, ensuring that regardless of the sample's specific state, the final oxygen concentration data inside the bottle is precisely controlled below the preset threshold. This fundamentally guarantees the anti-oxidation effect and the authenticity of the chemical state of the seabed sediment samples.

[0055] Optionally, the step of dynamically adjusting the initial nitrogen filling control parameters based on the concentration deviation signal includes:

[0056] When the concentration deviation signal indicates that the oxygen concentration data in the bottle is higher than the oxygen concentration threshold, the nitrogen flow rate in the initial nitrogen filling control parameters is increased, and the filling time is adaptively extended according to the rate of decrease of the oxygen concentration data in the bottle.

[0057] The adjusted nitrogen flow rate is combined with the extended charging time to generate the adjusted nitrogen charging control parameters.

[0058] Specifically, the nitrogen flow rate in the initial nitrogen purging control parameters is first adjusted upwards based on the amplitude of the concentration deviation signal. This adjustment typically follows a proportional control logic: the larger the amplitude of the concentration deviation signal, the larger the increase in the nitrogen flow rate, thereby accelerating oxygen removal by enhancing the purging intensity. For calculations... Adjusted nitrogen flow rate ,have:

[0059] ,

[0060] in, This is a preset proportional gain coefficient that determines the controller's sensitivity to deviations. Its value is obtained through experimental calibration or simulation, and its dimensions are matched with the units of nitrogen flow rate and concentration to ensure the equation holds true. Simultaneously, the filling time is extended more precisely and adaptively. The core of this process is to monitor and calculate the rate of decrease in oxygen concentration data within the bottle in real time. This rate of decrease is obtained by differentiating the continuously collected oxygen concentration data within the bottle over time, reflecting the instantaneous efficiency of the replacement process. This rate of decrease is compared with a dynamic expected rate. If the actual rate of decrease is significantly lower than this expected rate, it is determined that the oxygen concentration decrease is too slow and insufficient to complete the replacement within the remaining time. In this case, the current filling time is extended by a preset time step, and this extension operation can be repeated until the oxygen concentration decrease rate returns to normal or the total filling time reaches the preset maximum value. For example, if the current expected decrease in oxygen concentration is 0.1% every 10 seconds, but the actual decrease is only 0.05%, the filling time will be extended to compensate for this efficiency difference. Finally, the real-time adjusted nitrogen flow rate is combined with the adaptively extended charging time to generate a new set of dynamically changing adjusted nitrogen charging control parameters, which then drive the nitrogen charging unit. This dual regulation mechanism ensures that it can effectively address the challenges of high oxygen concentrations while also finely handling complex situations with low replacement efficiency. This maximizes the robustness of the control process and resource utilization efficiency while guaranteeing the final replacement effect, ensuring the stable and reliable achievement of the preset low-oxygen environment target.

[0061] Optionally, after using the driving pressure difference to drive the preset self-balancing exhaust valve to discharge residual gas, the method further includes:

[0062] The residual gas discharged is collected by a gas analyzer to obtain exhaust gas composition data;

[0063] Analyze the dynamic trends of oxygen and nitrogen content in the exhaust gas composition data to generate a displacement process state vector;

[0064] The state vector of the replacement process is used to determine whether the replacement process has reached the completion state.

[0065] Specifically, after the self-balancing exhaust valve is activated by the driving pressure difference to begin discharging the residual gas in the sampling bottle, a more refined replacement process monitoring and evaluation procedure is immediately initiated. The core of this procedure lies in the real-time online analysis of the discharged gas. In operation, a high-sensitivity gas analyzer is deployed at the exhaust port of the self-balancing exhaust valve to continuously sample and analyze the composition of all discharged residual gas, thereby uninterruptedly acquiring exhaust gas composition data. This exhaust gas composition data is a time-stamped sequence recording the changes in the concentration of each component in the exhaust, especially the dynamic evolution of oxygen and nitrogen content. Subsequently, the collected exhaust gas composition data undergoes in-depth analysis to capture the intrinsic state of the replacement process. The focus of the analysis is not isolated concentration values, but rather the dynamic trends in their content. As nitrogen replacement proceeds, the oxygen content in the discharged residual gas should show a monotonically decreasing trend, while the nitrogen content should show a monotonically increasing trend, eventually approaching saturation. This trend is quantified by calculating the instantaneous rate of change of nitrogen content, i.e., the first derivative of its concentration with respect to time. Finally, the key analytical results—namely, the absolute oxygen content and dynamic trends of nitrogen content in the real-time exhaust gas—are integrated into a multi-dimensional displacement process state vector, which is updated at each time point. For calculation... State vector of the permutation process at time step ,have:

[0066] ,

[0067] in, It is a gas analyzer in The oxygen content in the exhaust gas is measured at all times. yes The rate of change of nitrogen content in the exhaust gas is obtained through numerical differentiation calculations on continuous nitrogen content data points. This dynamically updated displacement process state vector provides a comprehensive and dynamic basis for subsequent accurate judgment of whether the displacement process has reached completion. It can effectively identify the transition of gas displacement from the initial stage of drastic change to the final stable saturation stage. In particular, by monitoring the trend of nitrogen content change, it can accurately capture the key inflection point when the displacement process reaches equilibrium and tends to be completed. This provides richer and more robust information for determining the displacement endpoint than a single concentration threshold, thus enabling a more accurate judgment of whether the displacement process has truly been completed, avoiding misjudgments caused by gas retention in local areas, and improving the thoroughness and reliability of the entire anti-oxidation treatment.

[0068] Optionally, determining whether the permutation process has reached a completion state based on the permutation process state vector includes:

[0069] Based on the state vector of the replacement process, feature extraction is performed to obtain the absolute value of oxygen content and the rate of change of nitrogen content.

[0070] The first comparison result is obtained by comparing the absolute value of the oxygen content with the preset endpoint setting value;

[0071] A second comparison result is obtained by comparing the nitrogen content change rate with a preset stability threshold;

[0072] Based on the first comparison result and the second comparison result, a logical AND operation is performed to determine whether the replacement process has reached the completion state.

[0073] Specifically, this method, based on the displacement process state vector generated in the previous step, executes a rigorous multi-condition logical judgment to accurately determine whether the displacement process has reached completion. First, features are extracted from the dynamically updated displacement process state vector, separating two core criteria: the absolute value of oxygen content in the discharged gas at the current moment, and the rate of change of nitrogen content. Then, parallel double comparisons are performed. The first comparison compares the extracted absolute value of oxygen content with a preset endpoint setpoint. This endpoint setpoint is predefined according to the highest requirements for sample preservation, representing the upper limit of acceptable residual oxygen concentration. For example, for deep-sea anaerobic sediments, the endpoint setpoint is often set between 0.01% and 0.05%. This value has been proven in practice to effectively prevent sample oxidation and meet the minimum oxygen content required for high-precision geochemical analysis. This comparison operation generates the first comparison result, used to determine whether the endpoint concentration of the displacement has met the standard. The second comparison compares the rate of change of nitrogen content with a preset stability threshold. This stability threshold is used to determine whether the rate of change of nitrogen content in the exhaust gas has approached zero, meaning that the displacement process has entered a stable saturation period from the dynamic displacement phase, and no longer significant oxygen is being displaced. This threshold is a very small but non-zero positive number, with a common range of 0.005% / s to 0.02% / s. This range is chosen to balance the sensitivity of the judgment with the ability to resist sensor noise and environmental disturbances. This comparison operation generates a second comparison result to determine whether the dynamic nature of the displacement process has terminated. Finally, a logical AND operation is performed on the two independent Boolean comparison results. Only when both conditions are met simultaneously is the displacement process finally determined to be complete. The Boolean flag used to calculate the completion status of the displacement process is... ,have:

[0074] ,

[0075] in, It is the preset endpoint setting value; It is the rate of change of nitrogen content extracted from the state vector of the displacement process; It is a preset stability threshold; The symbol represents a logical AND operation. This expression explicitly states that the replacement process is considered completely complete only when the discharged oxygen content is below the target value and the nitrogen content stabilizes and no longer changes significantly. By employing this two-condition logical AND judgment mechanism, this method greatly improves the accuracy and reliability of determining the completion status of the replacement. Constraining the replacement endpoint from two dimensions—"concentration target achieved" and "process stability"—ensures that the entire internal space of the sampling bottle, including the gas in the pores of the sediment, is completely replaced, providing a solid guarantee for the long-term oxidation-free preservation of the sample.

[0076] Optionally, the method further includes:

[0077] After determining that the replacement process has reached the completion state based on the state vector of the replacement process, a replacement completion signal is generated.

[0078] Send the replacement completion signal to the preset nitrogen charging unit and the self-balancing exhaust valve;

[0079] The nitrogen charging unit is controlled to stop charging nitrogen, and the self-balancing exhaust valve is closed to achieve a completely sealed state.

[0080] Specifically, once the replacement process has been definitively completed based on the state vector and the aforementioned dual-condition logic and judgment, a clear replacement completion signal is immediately generated. This replacement completion signal is essentially a high-priority instruction, marking the end of the active gas replacement phase and the beginning of the passive sealing and preservation phase. After generation, the replacement completion signal is simultaneously and without delay sent to two key execution units: the preset nitrogen charging unit and the controller of the self-balancing exhaust valve. Upon receiving the replacement completion signal, the two execution units immediately respond in unison. The nitrogen charging unit executes the instruction to stop charging nitrogen, and its internal control valve quickly closes, cutting off the high-pressure nitrogen source to the sampling bottle. Simultaneously, the self-balancing exhaust valve also executes the closing instruction, its valve core or disc moving to a fully closed position under drive, completely sealing the exhaust passage. Since the inlet and outlet are synchronously locked in the closed state, the sampling bottle now enters a final configuration known as a completely sealed state. In this completely sealed state, the sampling bottle forms an independent, airtight container completely isolated from the external environment. It is filled with fully replaced, high-purity nitrogen gas, completely sealing the sediment sample in a high-pressure, oxygen-free, inert atmosphere. By generating and executing a unified replacement completion signal, the synchronous and instantaneous closure of the two key channels—nitrogen inlet and outlet—is achieved.

[0081] Optionally, the method further includes:

[0082] Based on the completely sealed state, the pressure difference between the sampling bottle and the external environment pressure is continuously monitored to obtain the internal and external environmental pressure difference;

[0083] Based on the comparison between the internal and external environmental pressure difference and the preset stability range, a sealing status evaluation result is generated;

[0084] When the sealing condition assessment result indicates that the pressure difference between the internal and external environments exceeds the stability range, an alarm is triggered and the abnormal event is recorded.

[0085] Specifically, after the sampling bottle reaches a completely sealed state, this method does not terminate its monitoring function but initiates a long-term seal integrity assessment procedure. This seal integrity assessment procedure is based on continuous pressure monitoring. Specifically, it continues to use pressure sensors pre-installed inside and outside the sampling bottle to continuously collect real-time data on the pressure inside the bottle and the external environmental pressure. By synchronously comparing these two pressure data points, a key indicator, namely the pressure difference between the internal and external environments, is calculated. For the calculation... Pressure difference between internal and external environments at all times ,have:

[0086] ,

[0087] in, yes The pressure inside the sampling bottle is constantly being sampled. yes The external environmental pressure of the sampling bottle is constantly monitored. Under ideal sealing conditions, since the sampling bottle contains high-pressure nitrogen, the pressure difference between the internal and external environments should remain at a relatively stable positive value. Next, the calculated real-time pressure difference is compared with a preset stability range. This stability range is an interval that allows for normal fluctuations in the pressure difference; its upper and lower limits are typically preset based on factors such as the thermal expansion and contraction of materials, sensor drift, and small natural fluctuations in ambient temperature and pressure. This comparison process generates a sealing condition assessment result. If the real-time calculated internal and external environmental pressure difference remains within this stability range, the sealing condition assessment result is "normal." However, once the difference is detected to exceed the preset stability range, such as a sustained and significant drop in pressure difference, the seal is considered to be potentially faulty. At this point, the sealing condition assessment result changes to "abnormal," immediately triggering subsequent alarm and recording procedures. An alarm signal can be issued via sound, light, or remote communication, and detailed information such as the time and pressure data of the abnormal event is recorded in a log for subsequent analysis and processing. Figure 4As shown, the horizontal axis represents the time calculated from the completion of the replacement, and the vertical axis represents the pressure difference between the internal and external environments. The black solid line with dots in the figure represents the actual monitored change in the internal and external environmental pressure difference over time. The black solid line and dashed line represent the upper and lower limits of the preset stability range, i.e., the gray area enclosed in the figure, which is a safe range that allows for normal fluctuations. The diamond-shaped black block marks an anomaly point where the pressure difference exceeds the stability range, triggering an alarm. It can detect minute leaks caused by sealing ring aging, material fatigue, or accidental collisions in real time and with high sensitivity, realizing the transformation from "passively discovering problems" to "actively warning of anomalies." Once a leak occurs, it can immediately issue an alarm, thus buying valuable time for remedial measures and the rescue of precious samples, greatly improving the success rate of long-term preservation of seabed sediment samples and the reliability of the data.

[0088] Based on the same inventive concept, such as Figure 5 As shown, the present invention also provides a high-pressure self-balancing seabed sediment sampling bottle nitrogen-filled anti-oxidation system, the system comprising:

[0089] The physical feature acquisition module is used to acquire the physical feature parameters of the sediment in the sampling bottle;

[0090] The nitrogen filling parameter determination module is used to analyze and calculate based on the physical characteristic parameters to determine the initial nitrogen filling control parameters;

[0091] The driving pressure difference generation module is used to fill the sampling bottle with nitrogen gas based on the initial nitrogen filling control parameters, and simultaneously monitor the pressure inside the bottle and the external environmental pressure to generate a driving pressure difference;

[0092] The self-balancing exhaust drive module is used to drive a preset self-balancing exhaust valve using the driving pressure difference to discharge residual gas.

[0093] To verify the feasibility of this invention in practice, it was applied to a scientific expedition conducted in a certain sea area in August 2024. One of the core objectives of this expedition was to collect sulfide-rich sediment core samples. These samples are extremely sensitive to oxygen, and maintaining their original chemical state is crucial for subsequent geochemical and microbiological analyses. Traditional post-sampling processing methods are ineffective at isolating oxygen, leading to oxidation of the samples during their return to the laboratory, which seriously affects the accuracy of the research data. In this embodiment, the method and system proposed in this invention were used to perform on-site nitrogen purging to prevent oxidation of two representative seabed sediment samples.

[0094] In this embodiment, the research team used high-pressure self-balancing seabed sediment sampling bottles to collect samples at two sites with different geological characteristics. Sample 1 was loose sandy sediment, and sample 2 was dense clayey sediment. After collection, the nitrogen-filling anti-oxidation process of this invention was immediately initiated.

[0095] First, in-situ measurements of two samples were performed using an integrated sensor array, collecting data on water content, density, and particle size distribution. These data were then weighted and fused to generate comprehensive physical characteristic parameters. Subsequently, initial nitrogen purging control parameters were automatically calculated and set based on these parameters. During nitrogen purging, the oxygen concentration inside the bottle was monitored in real time, and the purging parameters were dynamically adjusted. Simultaneously, the completion status of the replacement process was accurately determined by analyzing the residual gas composition at the exhaust port, ultimately leading to a deadlock seal. The integrity of the seal was continuously monitored during subsequent transportation.

[0096] Specifically, for sample 1, which is loose sandy, the weighting coefficient is... , , Set the values ​​to 0.2, 0.3, and 0.5 respectively, and calculate the physical characteristic parameters as follows: The sample exhibits good permeability. Therefore, a relatively high nitrogen flow rate of 5.0 L / min and a relatively short initial charging time of 180 seconds were selected to achieve rapid replacement. For sample 2, a dense clay sample with a calculated physical characteristic parameter of 0.78, indicating poor permeability, a relatively low nitrogen flow rate of 2.0 L / min and a relatively long initial charging time of 400 seconds were selected to ensure that nitrogen could gently and fully penetrate deep into the sediment pores, avoiding disturbance to the sample structure.

[0097] During the processing of sample 2, the weighting coefficients , , Set the values ​​to 0.4, 0.5, and 0.1 respectively, and calculate the physical characteristic parameters as follows: It has poor permeability and is difficult to replace with nitrogen. At 150 seconds, a brief rebound in the oxygen concentration data inside the bottle was detected due to the slow release of gas inside the sediment, and the concentration deviation signal increased. The nitrogen flow rate was then temporarily increased to 2.5 L / min to enhance the purging effect, and the total filling time was adaptively extended to 450 seconds according to the change in the oxygen concentration decrease rate.

[0098] The endpoint determination of the replacement process employs a dual-condition logic. Replacement is considered complete when the gas analyzer detects that the oxygen content at the exhaust port is below 0.05%, i.e., the endpoint set value, and the nitrogen content change rate is less than 0.01% / s, i.e., the stabilization threshold. For example, sample 1 reaches this state at 185 seconds, while sample 2 reaches this state at 452 seconds. Upon determination, a replacement completion signal is immediately sent, and the nitrogen filling unit and self-balancing exhaust valve are simultaneously closed, bringing the sampling bottle into a completely sealed state with the internal pressure stabilizing at 20 MPa.

[0099] The system continued operating during the 48-hour transport from the research vessel back to the land-based laboratory. At the 36th hour, the pressure difference between the internal and external environments of Sample 2 decreased from a stable 19.8 MPa to 19.65 MPa, exceeding the preset stability range of ±0.1 MPa. An audible and visual alarm was immediately triggered, and the abnormal event was recorded. Inspection revealed that the slight loosening of a fastening bolt at the valve port was caused by severe rocking of the ship. After timely tightening, the pressure difference returned to normal, preventing continued slow leakage and oxidation of the sample.

[0100] Table 1. Data for determining the initial nitrogen filling control parameters for different sediment samples.

[0101]

[0102] Table 2. Data on the completion status of dynamic adjustment and replacement of sample 2

[0103]

[0104] Table 3. Sealing status assessment and abnormal alarm data for Sample 2

[0105]

[0106] Tables 1 to 3 above record the actual application data of the present invention when processing two typical seabed sediment samples, and demonstrate in detail its excellent performance in parameter adaptive setting, dynamic process control, accurate determination of replacement endpoint, and long-term sealed monitoring.

[0107] As can be seen from the data in Table 1, this invention enables personalized customization of nitrogen purging strategies based on quantitative analysis of the physical characteristics of samples. For two samples with vastly different permeability, distinctly different nitrogen purging parameters are automatically matched, fundamentally ensuring the scientific rigor and efficiency of the replacement process and avoiding potential under-purging or sample disturbances that may result from traditional "one-size-fits-all" methods.

[0108] Table 2 clearly demonstrates the advantages of the closed-loop feedback control mechanism. Faced with the unexpected gas release during the replacement process of Sample 2, it can respond quickly, effectively suppressing the rebound of oxygen concentration by coordinating the nitrogen flow rate and charging time, and ultimately ensuring the complete completion of the replacement process through strict dual-condition logic judgment. This intelligent regulation and precise judgment capability is key to ensuring the final anti-oxidation effect.

[0109] Table 3 data demonstrates the reliability of this invention throughout the entire sample preservation period. Continuous pressure monitoring successfully detected a minor leakage risk caused by transport disturbances, gaining valuable time for timely intervention and protection of the precious sample. Compared to traditional methods where the internal state is unknown after sealing, this invention represents a qualitative leap from "passive oxidation prevention" to "active protection." In summary, this invention, through an intelligent, closed-loop control process, significantly improves the accuracy, reliability, and overall safety of nitrogen-filled anti-oxidation treatment of high-pressure seabed sediment samples.

[0110] It should be noted that the electrical connections between the various units described above do not necessarily represent direct or indirect connections. Any indirect connection method can be applied to the embodiments of the present invention as long as it achieves the purpose of the present invention. The above descriptions are merely exemplary embodiments of the present invention and should not be construed as limiting the scope of the present invention.

[0111] All equivalent changes and modifications made in accordance with the teachings of this invention are still within the scope of this invention. Those skilled in the art will readily conceive of other embodiments of this invention upon considering the specification and the disclosure of practical truth. This application is intended to cover any variations, uses, or adaptations of this invention that follow the general principles of this invention and include common knowledge or conventional techniques in the art not described herein.

Claims

1. A method for nitrogen-filling and oxidation-preventing high-pressure self-balancing seabed sediment sampling bottles, characterized in that, The method includes: Obtain the physical characteristic parameters of the sediment in the sampling bottle; Based on the physical characteristic parameters, the initial nitrogen filling control parameters are determined through analysis and calculation. Nitrogen gas is injected into the sampling bottle based on the initial nitrogen filling control parameters, and the pressure inside the bottle and the external environmental pressure are monitored simultaneously to form a driving pressure difference; The preset self-balancing exhaust valve is driven by the driving pressure difference to discharge residual gas.

2. The method for nitrogen-filling and oxidation prevention of a high-pressure self-balancing seabed sediment sampling bottle according to claim 1, characterized in that, The physical characteristic parameters of the sediments obtained from the sampling bottle include: The water content, density, and particle size distribution data of the sediments were collected using a sensor array that integrates a near-infrared spectral probe, an acoustic impedance sensor, and a laser backscattering analyzer. The moisture content data, density data, and particle size distribution data are weighted and fused to generate physical characteristic parameters.

3. The method for nitrogen-filling and oxidation prevention of a high-pressure self-balancing seabed sediment sampling bottle according to claim 1, characterized in that, The step of analyzing and calculating the initial nitrogen filling control parameters based on the physical characteristic parameters includes: Based on the physical characteristic parameters and the preset nitrogen filling strategy, a matching nitrogen flow rate and filling time are obtained. The nitrogen flow rate and the charging time are combined to generate initial nitrogen charging control parameters.

4. The method for nitrogen-filling and oxidation prevention of a high-pressure self-balancing seabed sediment sampling bottle according to claim 1, characterized in that, The method further includes: Real-time monitoring of the gas environment inside the sampling bottle to obtain oxygen concentration data inside the bottle; The oxygen concentration data inside the bottle is compared with a preset oxygen concentration threshold to generate a concentration deviation signal; The initial nitrogen filling control parameters are dynamically adjusted based on the concentration deviation signal to generate the adjusted nitrogen filling control parameters.

5. The method for nitrogen-filling and oxidation prevention of a high-pressure self-balancing seabed sediment sampling bottle according to claim 4, characterized in that, The step of dynamically adjusting the initial nitrogen filling control parameters based on the concentration deviation signal includes: When the concentration deviation signal indicates that the oxygen concentration data in the bottle is higher than the oxygen concentration threshold, the nitrogen flow rate in the initial nitrogen filling control parameters is increased, and the filling time is adaptively extended according to the rate of decrease of the oxygen concentration data in the bottle. The adjusted nitrogen flow rate is combined with the extended charging time to generate the adjusted nitrogen charging control parameters.

6. The method for nitrogen-filling and oxidation prevention of a high-pressure self-balancing seabed sediment sampling bottle according to claim 5, characterized in that, The method of using the driving pressure difference to drive the preset self-balancing exhaust valve to discharge residual gas further includes: The residual gas discharged is collected by a gas analyzer to obtain exhaust gas composition data; Analyze the dynamic trends of oxygen and nitrogen content in the exhaust gas composition data to generate a displacement process state vector; The state vector of the replacement process is used to determine whether the replacement process has reached the completion state.

7. The method for nitrogen-filling and oxidation prevention of a high-pressure self-balancing seabed sediment sampling bottle according to claim 6, characterized in that, The step of determining whether the permutation process has reached a completion state based on the permutation process state vector includes: Based on the state vector of the replacement process, feature extraction is performed to obtain the absolute value of oxygen content and the rate of change of nitrogen content. The first comparison result is obtained by comparing the absolute value of the oxygen content with the preset endpoint setting value; A second comparison result is obtained by comparing the nitrogen content change rate with a preset stability threshold; Based on the first comparison result and the second comparison result, a logical AND operation is performed to determine whether the replacement process has reached the completion state.

8. The method for nitrogen-filling and oxidation prevention of a high-pressure self-balancing seabed sediment sampling bottle according to claim 7, characterized in that, The method further includes: After determining that the replacement process has reached the completion state based on the state vector of the replacement process, a replacement completion signal is generated. Send the replacement completion signal to the preset nitrogen charging unit and the self-balancing exhaust valve; The nitrogen charging unit is controlled to stop charging nitrogen, and the self-balancing exhaust valve is closed to achieve a completely sealed state.

9. A method for nitrogen-filling and oxidation prevention of a high-pressure self-balancing seabed sediment sampling bottle according to claim 8, characterized in that, The method further includes: Based on the completely sealed state, the pressure difference between the sampling bottle and the external environment pressure is continuously monitored to obtain the internal and external environmental pressure difference; Based on the comparison between the internal and external environmental pressure difference and the preset stability range, a sealing status evaluation result is generated; When the sealing condition assessment result indicates that the pressure difference between the internal and external environments exceeds the stability range, an alarm is triggered and the abnormal event is recorded.

10. A high-pressure self-balancing seabed sediment sampling bottle nitrogen-filling anti-oxidation system, applied to the high-pressure self-balancing seabed sediment sampling bottle nitrogen-filling anti-oxidation method as described in any one of claims 1-9, characterized in that, The system includes: The physical feature acquisition module is used to acquire the physical feature parameters of the sediment in the sampling bottle; The nitrogen filling parameter determination module is used to analyze and calculate based on the physical characteristic parameters to determine the initial nitrogen filling control parameters; The driving pressure difference generation module is used to fill the sampling bottle with nitrogen gas based on the initial nitrogen filling control parameters, and simultaneously monitor the pressure inside the bottle and the external environmental pressure to generate a driving pressure difference; The self-balancing exhaust drive module is used to drive a preset self-balancing exhaust valve using the driving pressure difference to discharge residual gas.

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