A method and system for intelligent control of sulfuric fluoride and nitrogen gas synergistic reduction fumigation

Abstract

The present application relates to the technical field of grain storage fumigation control, and discloses a kind of sulfuric fluoride and nitrogen gas synergistic reduced fumigation intelligent control method and system, comprising: opening isolation electromagnetic valve obtains the pressure and oxygen concentration data of multiple partitions, calculates the partition airflow resistance evaluation value;Combined with the preset reference concentration calculation low oxygen exposure cumulative value to determine the drug application trigger condition;When reaching the standard, the resistance evaluation value is used to adjust the parameters of flow controller and pressure regulating valve, and sulfuric fluoride release operation is executed to the target partition;Extract and send resistance and time data to generate control priority sequence;Concentration time integral value is monitored to execute local compensation release.Through quantitative evaluation of airflow resistance in the grain pile, the release mode is dynamically adjusted, the local drug application uniformity is improved, and the total consumption of drug is reduced;Combined with priority scheduling mechanism, the pipeline pressure balance during concurrent drug compensation is ensured, and the overall standard rate of fumigation process is ensured.

Description

Technical Field

[0001] This invention relates to the field of grain storage fumigation control technology, specifically to an intelligent control method and system for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen. Background Technology

[0002] In grain storage, the combined use of nitrogen modified atmosphere fumigation and chemical agents is a common method for controlling stored grain pests. With increasing demands for food safety and reduced chemical residues, the combined use of sulfuryl fluoride and nitrogen for reduced-dosage fumigation is gradually being applied. However, existing fumigation control methods have certain limitations in practical operations.

[0003] Traditional fumigation control systems typically apply uniform parameters to the entire grain pile without differentiation. However, in actual storage environments, differences in grain impurity content, pore structure, and compaction levels across different zones result in significantly varying airflow resistance. This uniform application ignores local resistance characteristics, leading to uneven distribution of fumigant within the grain pile and potential localized pesticide accumulation or insufficient concentration. Furthermore, existing control strategies largely rely on fixed time points or single overall concentration thresholds to trigger release, lacking dynamic quantitative assessment of the hypoxic exposure status of each zone. The control system cannot adjust the application rate and release pattern in conjunction with the actual resistance of different zones. This indiscriminate application often results in excessive chemical consumption, making it difficult to achieve true pesticide reduction goals.

[0004] Furthermore, in the complex multi-zone operation of large grain silos, when multiple areas are found to have substandard fumigation concentrations requiring supplemental application, existing technologies lack a priority scheduling mechanism to address concurrent demands. Directly opening multiple valves in the control system can easily cause pressure imbalances in the supply pipelines, affecting release accuracy. Moreover, conventional supplemental application operations typically lack continuous tracking of concentration and time integration, making it impossible for the system to accurately determine the true effect of localized compensation release, thus hindering the stable achievement of fumigation standards across all zones. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a method and system for intelligent control of synergistic reduction fumigation using sulfuryl fluoride and nitrogen. This method solves the problems in traditional fumigation operations, such as uneven distribution of local agents due to differences in airflow resistance within the grain pile, excessive consumption of chemical agents due to blind application, and pipeline pressure imbalance and lack of quantitative control basis for local replenishment when multiple zones are applied concurrently.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The first aspect of this invention provides a smart control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen, comprising the following steps: The isolation solenoid valve is opened to initiate nitrogen circulation and replacement operations. Pressure change signals and oxygen concentration data for multiple zones within the grain pile are acquired via a measurement bypass. Specifically, an action command is sent to the interlocking switching valve group located between the main application pipe and the air inlet pipe, temporarily connecting the main application pipe to the nitrogen source while maintaining isolation between the main application pipe and the sulfuryl fluoride source. A transient opening command is sent to the branch valve corresponding to the target zone, causing the branch valve to perform a short-term opening and closing action to inject nitrogen into the target zone through the application branch. Peak pressure response data and pressure recovery time are captured by a micro-pressure sensor and recorded into the system.

[0007] Furthermore, based on pressure change signals and oxygen concentration data, pressure characteristic values ​​and oxygen concentration decay characteristic values ​​for each zone are extracted, and the zone airflow resistance evaluation value is calculated. This step includes: retrieving the initial ambient pressure as the reference pressure, continuously monitoring the pressure value and extracting the maximum pressure value as the pressure peak; extracting the time-series data of oxygen concentration within a preset time window, obtaining the absolute rate of decrease of local oxygen concentration over time by calculating the ratio of the change in oxygen concentration to the corresponding time difference; using the difference between the pressure peak and the reference pressure as the divisor, and the sum of the absolute rate of decrease of oxygen concentration and the correction constant as the divisor, the zone airflow resistance evaluation value is obtained through division.

[0008] The system reads real-time oxygen concentration parameters and calculates the cumulative hypoxia exposure value for each zone based on a preset hypoxia reference concentration, determining whether it has reached the pre-treatment trigger threshold. During the calculation, the collected real-time oxygen concentration parameters are dynamically compared with the preset hypoxia reference concentration. When the real-time oxygen concentration parameter is lower than the preset hypoxia reference concentration, hypoxia exposure time series tracking is initiated. The difference between the preset hypoxia reference concentration and the real-time oxygen concentration parameter is obtained, multiplied by a conditional control coefficient, and the product is integrated and accumulated over time to obtain the cumulative hypoxia exposure value. The conditions for integration accumulation are as follows: when the preset hypoxia reference concentration is greater than the real-time oxygen concentration parameter, the conditional control coefficient is set to one, and normal difference accumulation is performed; when the real-time oxygen concentration parameter is greater than or equal to the preset hypoxia reference concentration, the conditional control coefficient is set to zero, and the integration accumulation operation is paused; when the duration of the conditional control coefficient being zero exceeds the reset time threshold, the accumulated hypoxia exposure value is cleared to zero.

[0009] When the cumulative hypoxia exposure value of the target zone in each zone reaches the pre-treatment trigger threshold, the corresponding isolation solenoid valve is closed and the branch valve is opened. The mass flow controller parameters are adjusted using the corresponding zone airflow resistance evaluation value to perform a sulfuryl fluoride release operation to the target zone. During this process, the zone airflow resistance evaluation value corresponding to the target zone is compared with the airflow resistance classification threshold. If the zone airflow resistance evaluation value is higher than or equal to the airflow resistance classification threshold, the output pressure setting value of the pressure regulating valve configured on the drug delivery pipeline is increased, and the release flow rate is adjusted in conjunction with the mass flow controller to control the branch valve to perform periodic opening and closing actions to form an intermittent release airflow. If the zone airflow resistance evaluation value is lower than the airflow resistance classification threshold, the output pressure setting value of the pressure regulating valve is decreased, and the flow rate setting value of the mass flow controller is decreased to keep the branch valve in a continuously open state.

[0010] When performing the above-mentioned release operation, if there are multiple concurrent target zones, the steps for allocating the control sequence include: extracting the zone airflow resistance evaluation value and the target timestamp of the concurrent target zone; multiplying the dimensionless value of the zone airflow resistance evaluation value after range normalization with the resistance weight coefficient to obtain the first product; multiplying the dimensionless value of the target waiting time calculated from the target timestamp after range normalization with the time waiting weight coefficient to obtain the second product; adding the first product and the second product to obtain the comprehensive priority value; arranging the comprehensive priority value in descending order to generate the drug delivery execution sequence queue; and opening the corresponding branch valves one by one according to the drug delivery execution sequence queue to perform single-zone rotational drug delivery.

[0011] The system monitors the sulfuryl fluoride concentration and time integral value of the target zone, determines and executes local compensation release operations, and initiates ventilation and exhaust operations after meeting the process specifications. Specific steps include: calculating the time integral of the real-time sulfuryl fluoride concentration in each zone during the sealing period to obtain the sulfuryl fluoride concentration and time integral value; extracting the total fumigation acceptance threshold and dividing it by the planned total fumigation duration to obtain the target cumulative constant per unit time; multiplying the current execution time by the target cumulative constant and then by the tolerance coefficient to obtain the dynamic reference lower limit; when the sulfuryl fluoride concentration and time integral value are lower than the corresponding dynamic reference lower limit, a local replenishment trigger command is generated for the non-compliant zone, and a local compensation release operation is initiated.

[0012] When initiating a local compensation release operation, the airflow resistance evaluation value of the substandard zone is retrieved. If the zone's airflow resistance evaluation value is higher than the preset airflow resistance grading threshold, the output pressure setting of the pressure regulating valve on the application pipeline is increased, and the branch valve is controlled to release the compensation dose using a short pulse method. If the zone's airflow resistance evaluation value is lower than the preset airflow resistance grading threshold, the output pressure setting of the pressure regulating valve is decreased, and the compensation dose is released using a lower constant flow rate. After each compensation action, the compensation status counter is incremented by one. When the cumulative number of compensations reaches the maximum compensation number threshold and the sulfuryl fluoride concentration and time integral value are still lower than the dynamic reference lower limit, the automatic compensation program is terminated, and an abnormal warning signal is output.

[0013] A second aspect of this invention provides an intelligent control system for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen, used to implement the above-mentioned intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen, comprising: The system includes a gas source device comprising a nitrogen gas source and a sulfuryl fluoride gas source; a circulation device connected to the internal storage space containing grain piles, including an air inlet pipe connected to the nitrogen gas source; a pesticide application device comprising a main application pipe connected to the sulfuryl fluoride gas source, and multiple application branches branching from the main application pipe, the ends of which are connected to probes; the main application pipe is equipped with a mass flow controller and a pressure regulating valve; an interlocking switching valve group located between the main application pipe and the air inlet pipe; a sensor assembly comprising a micro-pressure sensor, an oxygen concentration sensor, and a sulfuryl fluoride concentration sensor; a measurement bypass, one end connected to the pipe section containing the probe, and the other end connected to the sensor assembly, the measurement bypass being equipped with an isolation solenoid valve; and a control unit establishing communication connections with the main valves of the nitrogen gas source and the sulfuryl fluoride gas source, the interlocking switching valve group, the mass flow controller, the pressure regulating valve, the isolation solenoid valve, and the sensor assembly.

[0014] This invention provides a smart control method and system for synergistic reduction of fumigation volume using sulfuryl fluoride and nitrogen. It has the following beneficial effects: 1. This invention calculates the airflow resistance evaluation value of each zone by acquiring peak pressure response data and the absolute rate of oxygen concentration decrease in multiple zones within the grain pile. This technical feature can quantitatively evaluate the pore structure and airflow obstruction status of different zones within the grain pile, providing objective data support for subsequent pesticide application operations. It avoids localized pesticide accumulation or insufficient concentration caused by traditional indiscriminate pesticide application, and improves the uniformity of fumigation gas distribution within the grain pile.

[0015] 2. This invention triggers pesticide application based on cumulative low-oxygen exposure values ​​and dynamically adjusts the parameters of the mass flow controller and pressure regulating valve using zoned airflow resistance evaluation values. By using intermittent airflow release in high airflow resistance areas and constant flow release at lower flow rates in low airflow resistance areas, this targeted dynamic release control effectively achieves synergistic application of sulfuryl fluoride and nitrogen, reducing the total consumption of chemical agents while ensuring the fumigation effect of the local target area.

[0016] 3. This invention calculates the sulfuryl fluoride concentration and time integral value and compares it with the dynamic reference lower limit. It automatically initiates local compensation release operations for non-compliant zones. Simultaneously, when multiple zones are treated concurrently, it generates a dosing execution sequence queue by combining resistance and waiting time weights. These technical features not only ensure the compliance rate of the fumigation process in each zone but also avoid system pipeline pressure imbalance caused by multiple concurrent dosing operations, thus ensuring the stability of the fumigation control process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the sulfuryl fluoride and nitrogen synergistic reduction fumigation system according to an embodiment of the present invention; Figure 2 This is a flowchart illustrating the overall process of the sulfuryl fluoride and nitrogen synergistic fumigation reduction method according to an embodiment of the present invention. Figure 3 This is a control timing diagram for the system initialization and nitrogen filling detection stages in an embodiment of the present invention; Figure 4 This is a block diagram illustrating the logic for calculating the zoned airflow resistance evaluation value in an embodiment of the present invention. Figure 5 This is a logic diagram for determining the accumulation of hypoxia exposure and drug administration triggering in an embodiment of the present invention; Figure 6 This is a schematic diagram showing the changes in oxygen concentration and sulfuryl fluoride concentration in each zone according to an embodiment of the present invention. Detailed Implementation

[0018] The technical solutions in 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, and 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.

[0019] See attached document Figure 1 The present invention provides an intelligent control system for synergistic reduction of fumigation by thioyl fluoride and nitrogen, including a gas source device, a circulation device, a dosing device, a measurement bypass, a sensor assembly, and a control unit.

[0020] The gas supply device includes a nitrogen gas source and a sulfuryl fluoride gas source.

[0021] The circulation system is connected to the internal storage space where grain piles are stored. The circulation system includes a circulation fan, an inlet duct, and a return duct. A nitrogen gas source is connected to the inlet duct.

[0022] The application device is connected to the storage space and includes a main application pipe connected to a sulfuryl fluoride gas source, and multiple application branches branching from the main application pipe. The main application pipe can be located outside the storage space, and the application branches extend at least partially into the storage space. Each application branch is connected to a probe at its end, which extends into different depths within the grain pile. Branch valves are correspondingly installed at the connections between the main application pipe and the multiple application branches. A mass flow controller is installed on the main application pipe. In embodiments requiring automatic adjustment of release pressure, the main application pipe is also equipped with an electric pressure reducing valve, a proportional pressure regulating valve, or an equivalent pressure regulating valve; in embodiments with only a mass flow controller, the control unit adjusts the application intensity by regulating the mass flow rate, release duration, valve opening and closing cycle, or compensation dosage.

[0023] In addition, an interlocking switching valve assembly is installed between the main application pipe and the air inlet pipe to establish a temporary passage for nitrogen to enter the application branch during short-term nitrogen detection pulse conditions. The interlocking switching valve assembly allows only one of the nitrogen or sulfuryl fluoride gas sources to be connected at any given time, and keeps the main sulfuryl fluoride gas source valve closed during short-term nitrogen detection pulses to prevent direct cross-contamination between the nitrogen and sulfuryl fluoride gas sources or accidental release of sulfuryl fluoride.

[0024] Each application branch is equipped with a measurement bypass in parallel. One end of the measurement bypass connects to the pipe section where the probe is located, and the other end connects to the sensor assembly. An isolation solenoid valve, a check valve, and a flow restrictor are sequentially installed on the measurement bypass.

[0025] The sensor assembly includes a micro-pressure sensor, an oxygen concentration sensor, and a sulfuryl fluoride concentration sensor. All three sensors are connected to the end of the measurement bypass to achieve simultaneous sampling of the gas state in the local area where the probe is located. A sampling valve assembly, a filter unit, a flow-limiting unit, and a sampling pump can be installed between the sensor assembly and the measurement bypass. The oxygen concentration sensor and the micro-pressure sensor are made of sulfuryl fluoride-resistant material, or they can be isolated from the sulfuryl fluoride-containing gas sample by the sampling valve assembly during the sulfuryl fluoride concentration sampling stage. The sulfuryl fluoride concentration sensor collects gas samples through an independent sampling branch or a controlled sampling valve assembly. This structure reduces the risk of sulfuryl fluoride contaminating non-target sensors or causing measurement drift.

[0026] The control unit establishes communication connections with the main valves, circulating fans, branch valves, mass flow controllers, isolation solenoid valves, interlocking switching valve groups, and sensor assemblies of the nitrogen and sulfuryl fluoride gas sources. The control unit is internally equipped with storage media and a processor.

[0027] See attached document Figure 2 This invention provides a smart control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen, comprising the following steps: S10, the control unit opens the isolation solenoid valve to establish a gas passage between the probe and the sensor assembly, and starts the nitrogen circulation replacement operation. During the nitrogen filling process, the pressure change signals and oxygen concentration data of multiple zones in the grain pile are obtained through the measurement bypass. S20, the control unit extracts the pressure characteristic value and oxygen concentration decay characteristic value of each zone during the nitrogen filling process, and calculates the zone airflow resistance evaluation value that characterizes the magnitude of the airflow resistance inside the grain pile. S30, the control unit reads the real-time concentration parameters fed back by the oxygen concentration sensor, calculates the cumulative value of hypoxia exposure in each zone in combination with the preset hypoxia reference concentration, and continuously judges whether the cumulative value of hypoxia exposure in each zone reaches the preset drug triggering threshold. S40, when the cumulative value of hypoxia exposure in the target zone reaches the pre-treatment trigger threshold, the control unit closes the isolation solenoid valve corresponding to the target zone and opens the branch valve. The working parameters of the mass flow controller are dynamically adjusted using the zone airflow resistance evaluation value corresponding to the target zone as the adjustment variable, and the sulfuryl fluoride release operation is performed to the target zone. S50: After the initial release operation is completed, the control unit monitors the local sulfur fluoride concentration and time integral value based on the data fed back by the sulfur fluoride concentration sensor, judges and executes the local compensation release operation, and starts the ventilation and exhaust operation when the fumigation maintenance time meets the process setting specifications.

[0028] See attached document Figure 3 When implementing the synergistic reduction fumigation method of sulfuryl fluoride and nitrogen, the control unit opens the isolation solenoid valve to establish a gas passage between the probe and the sensor assembly, and initiates the nitrogen circulation replacement operation. During the nitrogen filling process, pressure change signals and oxygen concentration data of multiple zones in the grain pile are obtained through the measurement bypass. The specific execution process includes the following sub-steps: S11, the control unit performs initial pipeline configuration and physical isolation operations. The control unit sends a control command to the application device to maintain the main valve of the sulfuryl fluoride gas source and all branch valves on the application branches in the closed state, cutting off the delivery path of sulfuryl fluoride into the storage space. The control unit sends a trigger command to the measurement bypass to open the isolation solenoid valve on the measurement bypass. Through this action, the probe at the end of the application branch is connected to the sensor assembly, making the probe a local gas state acquisition end distributed within the grain pile at this stage. The flow-limiting orifice inside the measurement bypass is used to constrain the gas flow rate into the sensor assembly, reducing the risk of impact on the sensitive components of the sensor assembly when transient high pressure occurs inside the grain pile. The check valve inside the measurement bypass is used to limit the reverse flow of gas within the measurement bypass, preventing gas or residual gas from flowing back to the probe, application branch, or application main.

[0029] S12, the control unit initiates the nitrogen circulation replacement and gas circulation monitoring operation. The control unit turns on the nitrogen source in the gas supply device and starts the circulation fan of the circulation device. Nitrogen is introduced into the storage space through the air inlet pipe, forming a circulating air field that penetrates the internal pores of the grain pile under the drive of the circulation fan. At this stage, due to the differences in the degree of compaction and porosity in different areas inside the grain pile, the resistance to nitrogen penetration through the high compaction area is greater, resulting in slow replacement of the old air in that local area and easy formation of local back pressure increase; while the replacement in areas with higher porosity is faster.

[0030] Based on the aforementioned fluid dynamics principles, the micro-pressure sensor in the sensor assembly continuously reads the gas pressure change signals at the locations of the probes in each zone through the probe tube and measurement bypass. Simultaneously, the oxygen concentration sensor synchronously reads the local oxygen concentration parameters. The control unit processes the aforementioned analog signals at a set sampling period and stores them in the storage medium. Regarding the initial speed setting of the circulating fan and its matching with the overall airflow, those skilled in the art can adjust the basic operating parameters according to the physical volume and airtightness characteristics of the storage space. The equipment drive and basic airflow control are well-known technologies in the field and will not be elaborated upon here.

[0031] S13, the control unit applies a short-duration nitrogen detection pulse for auxiliary airflow detection. To obtain a more obvious local airflow resistance response, the control unit can trigger a short-duration nitrogen detection pulse during nitrogen circulation replacement. Before performing this step, the control unit first confirms that the main valve of the sulfuryl fluoride gas source is closed and that there is no sulfuryl fluoride release pressure in the main injection pipe. The control unit sends an action command to the interlock switching valve group located between the main injection pipe and the air inlet pipe, temporarily connecting the main injection pipe to the nitrogen gas source while maintaining isolation between the main injection pipe and the sulfuryl fluoride gas source.

[0032] Subsequently, the control unit sends a transient opening command to the branch valve corresponding to the target zone. The branch valve performs a short-term opening and closing action according to this command; the duration of this transient opening is typically set to 0.5 to 2.0 seconds. This action allows a small amount of nitrogen gas to be directly injected into the target zone through the application branch, creating an independent local pressure response in the area surrounding the probe.

[0033] The micro-pressure sensor in the sensor assembly captures the peak data of the pressure response and the pressure recovery time. The control unit records the captured data into the system as a data source for subsequent calculation of the zone airflow resistance evaluation value. Due to the short opening time and low charging flow rate, this operation usually does not substantially interfere with the overall nitrogen replacement process. After the pulse detection is completed, the control unit controls the interlock switching valve group to reset to standby state and continues to keep the main sulfuryl fluoride gas source valve closed until the subsequent dosing trigger conditions are met before allowing sulfuryl fluoride release.

[0034] See attached document Figure 4 The control unit extracts the pressure characteristic values ​​and oxygen concentration decay characteristic values ​​of each zone during the nitrogen filling process, and calculates the zone airflow resistance evaluation value, which characterizes the magnitude of airflow resistance inside the grain pile. The specific execution process includes the following sub-steps: S21, the control unit extracts pressure characteristic values ​​and oxygen concentration decay characteristic values ​​from the continuous time-series data fed back by the sensor components. For the pressure characteristic values, the control unit retrieves the initial ambient pressure of the corresponding zone recorded by the micro-pressure sensor during the system initialization phase as the reference pressure. During nitrogen purging or the application of a short-duration nitrogen detection pulse, the control unit continuously monitors the values ​​of the micro-pressure sensor and extracts the maximum pressure value within that specific time period as the pressure peak. The difference between the reference pressure and the pressure peak physically reflects the resistance overcome or the back pressure formed by the fluid penetrating the medium in that area.

[0035] To detect the characteristic value of oxygen concentration decay, the control unit extracts time-series data of oxygen concentration within a preset time window. By calculating the ratio of the change in oxygen concentration to the corresponding time difference, the absolute rate of decrease in local oxygen concentration over time is obtained. The duration of this preset time window is typically set based on the estimated time required for the circulating fan to drive the gas in the chamber to complete one macroscopic cycle, and the value range is configured to be between 30 seconds and 120 seconds.

[0036] To reduce the impact of differences in application branch length, probe orifice diameter, sensor response time, and measurement pipeline volume on the calculation results, the control unit can call a pre-calibrated zoning correction coefficient before calculating the zoning airflow resistance evaluation value to perform baseline correction or normalization of pressure peak, reference pressure, or oxygen concentration decay rate. The zoning correction coefficient can be obtained through empty chamber testing, normal oxygen ventilation testing, or short-time detection of standard flow nitrogen.

[0037] This absolute rate is used to characterize the speed at which the original air in the target zone is dispersed or replaced by nitrogen. For extremum finding and difference operations of one-dimensional time-series signals, those skilled in the art can implement them using conventional digital signal processing algorithms. Specific data filtering and peak-finding rules are well-known techniques in this field and will not be elaborated upon here.

[0038] S22, the control unit constructs a zoned airflow resistance evaluation value based on the extracted pressure characteristic value and oxygen concentration decay characteristic value. Due to the non-uniformity of compaction and pore distribution within the grain pile, a single gas pressure or concentration parameter is easily affected by the probe location. Combining local pressure response characteristics and gas concentration decay characteristics can better characterize the ease with which fluid can reach that area. The control unit calculates the zoned airflow resistance evaluation value for the i-th zone according to the following formula, based on internally stored calculation rules: ; In the formula, Indicates the first Evaluation values ​​of airflow resistance in each zone; Indicates the first The pressure peak detected in each partition; Indicates the first The baseline stress recorded in each partition; Indicates the first The absolute rate at which the oxygen concentration in each zone decreases within a preset time window; This is a correction constant.

[0039] Under the above calculation method, when the measured pressure difference in the target area is large and the oxygen concentration decreases slowly, the calculated... A high value indicates that the grain pile in this area has high compaction or low porosity, hindering fluid penetration; when the measured pressure difference is small and the oxygen concentration decreases rapidly, the calculated value is... The lower value indicates that the area has larger pores and a physical channel for rapid airflow diffusion.

[0040] S23, the control unit invokes the zero-correction process when executing the above calculation logic. In actual warehouse environments, if there is localized blockage, dust accumulation, or insufficient gas flow in the area where the probe is located, the local oxygen concentration may remain constant for a prolonged period during nitrogen filling, leading to errors in the calculated extraction... Approaching zero.

[0041] To prevent the system from crashing due to a division-to-zero error caused by the underlying control program performing division operations, the control unit presets a correction constant in the denominator of the calculation formula. This constant is a very small positive real number, and its value is matched to the detection resolution of the oxygen concentration sensor, typically ranging from 0.001 to 0.01. Introducing this constant ensures the continuous and stable operation of the processor module without substantially interfering with the determination of the relative magnitude of the resistance evaluation value under normal conditions. The calculated values ​​for each partition... The partitioned airflow resistance parameter table is entered into the system storage medium for use in subsequent stages when dynamically adjusting the operating parameters of the mass flow controller and branch valves.

[0042] See attached document Figure 5 During the nitrogen replacement process, the control unit continuously tracks the evolution of the local hypoxic environment and assesses the degree of hypoxic exposure caused to pests inside the grain pile, thereby dynamically determining the appropriate time to apply sulfuryl fluoride. The specific execution process includes the following sub-steps: S31, the control unit performs time-series tracking of oxygen concentration and defines the effective hypoxia stage. The control approach based on this step is that stored grain pests typically exhibit respiratory metabolic stress or altered ventilation behavior under sustained hypoxia, and their sensitivity to fumigants changes with the degree and duration of hypoxia exposure. This scheme does not use any specific spiracular behavior as the sole criterion for judgment, but rather uses the degree to which the oxygen concentration in the target area remains below the preset hypoxia reference concentration as the trigger control parameter for pesticide application.

[0043] The control unit continuously reads the real-time oxygen concentration parameters at the location of the probe in each zone using an oxygen concentration sensor in the sensor assembly. The control unit pre-stores a low-oxygen reference concentration, which can be set based on the target pest species, insect stage, food variety, temperature, humidity, and previous experimental data, with a configurable range of 2% to 5%. The control unit dynamically compares the collected real-time oxygen concentration parameters with the low-oxygen reference concentration. When the real-time oxygen concentration in the target zone falls below the low-oxygen reference concentration, the control unit determines that the local area has entered an effective low-oxygen phase and initiates a low-oxygen exposure time-series tracking time for that zone.

[0044] S32, the control unit calculates the cumulative hypoxia exposure value of the zone that has entered the effective hypoxia stage. A single transient concentration value or a simple exposure time value is insufficient to accurately measure the degree of hypoxia exposure experienced by pests. The control unit uses the integral of the concentration difference over time to quantify the cumulative effect. The control unit calculates the value according to the following formula... Cumulative hypoxia exposure values ​​for each zone: ; In the formula, Indicates the first Cumulative values ​​of hypoxia exposure in each zone; This indicates the starting point at which the real-time oxygen concentration in the target zone first drops below the low-oxygen reference concentration; Indicates the current real-time moment of the system's operation; This indicates the system's preset low oxygen reference concentration; Indicates the first Each partition Real-time oxygen concentration parameters measured at all times; Indicates the relationship with the first The conditional control coefficients corresponding to each partition.

[0045] To prevent local oxygen backflow from distorting the cumulative value calculation, the control unit uses conditional control coefficients. The system implements a pause mechanism for integration, supplemented by a timeout reset mechanism. The control unit operates based on real-time oxygen concentration parameters. Compared with low oxygen reference concentration The dynamic size relationship is determined in real time. The value of: when Greater than hour, When the value is 1, the control unit performs normal difference accumulation; when Rebound and greater than or equal to hour, When the value of is 0, the product within the expression is zero, and the control unit is equivalent to pausing the integral accumulation operation of the current partition.

[0046] like If the duration of a value of 0 exceeds the system's set reset time threshold, which is typically set to 10 to 30 minutes based on the experience of pests' physiological functions returning to normal, the control unit determines that the previous low-oxygen environment has been disrupted and then resets the accumulated oxygen levels. The values ​​are zeroed out to ensure that the cumulative hypoxia exposure values ​​calculated subsequently accurately reflect the continuous and effective hypoxia stress process. For the discretization of the above continuous-time domain integration operation in a microprocessor, those skilled in the art can use conventional fixed-step-size accumulation and summation algorithms for engineering transformation; this is a well-known technique in the field and will not be elaborated upon here.

[0047] S33, the control unit performs multi-dimensional comparison and command generation operations for the pesticide application trigger threshold. The control unit continuously cross-compares the cumulative hypoxia exposure values ​​of each zone, calculated in real time, with the pre-set pesticide application trigger threshold. The pre-set pesticide application trigger threshold characterizes the minimum cumulative hypoxia required for the pest population in the target area to reach a hypoxia exposure state due to a hypoxia environment. This threshold has the dimensional characteristics of concentration percentage multiplied by time, and its specific value is set based on the bioassay statistics of the storage environment in the early stages and written into the storage medium. When the cumulative hypoxia exposure value of a target zone is detected to reach the pre-set pesticide application trigger threshold, the control unit determines that the target area meets the pesticide application triggering conditions. The control unit internally assigns a control priority for this zone, identifies the corresponding internal status, and generates a corresponding pesticide application preparation command. This command triggers subsequent hardware linkage processes, enabling the control unit to retrieve the zone airflow resistance evaluation value corresponding to that specific zone and configure the corresponding fluid hardware actions.

[0048] When the cumulative hypoxia exposure value of the target zone reaches the pre-treatment trigger threshold, the control unit closes the isolation solenoid valve corresponding to the target zone and opens the branch valve. Using the zone airflow resistance evaluation value corresponding to the target zone as the adjustment variable, the operating parameters of the mass flow controller are dynamically adjusted to perform a sulfuryl fluoride release operation to the target zone. The specific execution process includes the following sub-steps: S41, the control unit performs circulation state adjustment and drug application pipeline switching. When a target zone is determined to meet the drug application triggering conditions, the control unit sends a control command to the measurement bypass to close the isolation solenoid valve corresponding to the target zone, cut off the gas connection path between the probe and sensor assembly of that zone, and suspend the local micro-pressure and concentration sampling operation.

[0049] Subsequently, the control unit confirms that the short-term nitrogen detection pulse path is closed and controls the interlock switching valve group to switch to the sulfuryl fluoride release operation state, connecting the main application pipe to the sulfuryl fluoride gas source while maintaining isolation between the main application pipe and the nitrogen gas source. The control unit opens the main sulfuryl fluoride gas source valve or the corresponding sulfuryl fluoride release valve and opens the branch valves corresponding to the target zone, while keeping the branch valves of non-target zones closed. Thus, sulfuryl fluoride sequentially enters the corresponding grain pile area through the sulfuryl fluoride gas source, pressure reducing valve or pressure regulating valve, mass flow controller, main application pipe, target zone branch valves, and target zone probe, forming a single-path application channel from the sulfuryl fluoride gas source to the target zone probe.

[0050] During this stage, to prevent excessive dilution of the locally released small amount of sulfuryl fluoride by the overall circulating airflow within the storage area, the control unit sends an operational intervention command to the circulation device. Specifically, the control unit determines the intervention method based on the overall oxygen concentration within the storage space: if most areas within the storage area are still in the nitrogen replacement phase, the circulation fan is controlled to reduce its operating speed; if most areas within the storage area have entered a low-oxygen state, the circulation fan is controlled to suspend operation. This intervention control creates a relatively still local airflow around the target zone, which is beneficial for the effective retention of subsequently released agents within the local pores.

[0051] S42, the control unit performs graded adjustments to the release parameters based on the zone airflow resistance evaluation value. The control unit retrieves the zone airflow resistance evaluation value corresponding to the target zone from the storage medium. The control unit is pre-configured with airflow resistance grading thresholds, which are set based on the pressure drop statistics of historical fumigation operations in the specific storage space or calibration data during empty warehouse testing. The control unit compares the retrieved zone airflow resistance evaluation value with the airflow resistance grading threshold and outputs the corresponding control electrical signal based on the comparison result.

[0052] If the airflow resistance evaluation value of the target zone is higher than or equal to the airflow resistance grading threshold, it indicates that the grain pile compaction degree of that zone is high and the natural gas diffusion resistance is large. The control unit then activates the pulse release mode. In embodiments where the main spraying pipe is equipped with an electric pressure reducing valve, a proportional pressure regulating valve, or an equivalent pressure regulating valve, the control unit increases the output pressure setpoint of the pressure regulating valve and adjusts the release flow rate in conjunction with the mass flow controller. In embodiments where the main spraying pipe is only equipped with a mass flow controller without an independent pressure regulating valve, the control unit does not perform pressure setpoint adjustment. Instead, it increases the release intensity per unit time of the target zone by increasing the mass flow setpoint, extending the single opening time, increasing the pulse width, increasing the number of pulse releases, or increasing the compensation dose. Simultaneously, the control unit controls the corresponding branch valve to perform periodic opening and closing actions, such as opening for one second and closing for two seconds, so that the sulfuryl fluoride gas forms an intermittent release airflow to improve the ability of the agent to enter the high airflow resistance area.

[0053] If the airflow resistance evaluation value of the target zone is lower than the airflow resistance grading threshold, it indicates that the porosity of the zone is large, and the control unit switches to constant flow slow release mode. In embodiments where the main injection pipe is equipped with an electric pressure reducing valve, a proportional pressure regulating valve, or an equivalent pressure regulating valve, the control unit lowers the output pressure setting value of the pressure regulating valve and lowers the flow setting value of the mass flow controller. In embodiments where the main injection pipe is only equipped with a mass flow controller and not an independent pressure regulating valve, the control unit does not perform pressure setting adjustment, but instead lowers the mass flow setting value, shortens the release time, reduces the pulse release frequency, or reduces the number of releases. The control unit maintains the target zone branch valve in a continuously open or low-frequency open state to release the sulfuryl fluoride agent to the target zone at a lower stable flow rate, reducing the possibility of the agent rapidly migrating out of the target area in the pores.

[0054] S43, the control unit performs priority scheduling and rotational drug application for concurrent responses in multiple zones. During continuous monitoring of the system, multiple zones within the storage space simultaneously or successively reach the drug application trigger condition. The control unit manages the allocation order of fluid hardware resources by executing built-in priority sorting rules. When multiple zones are detected and the trigger condition is met, the control unit extracts the zone airflow resistance evaluation value and the achievement timestamp of these target zones, and calculates the comprehensive priority value of each zone according to the following formula: ; In the formula, Indicates the first The overall priority value of each partition; Indicates the first The dimensionless values ​​of the zone airflow resistance evaluation values ​​after range normalization. Indicates the first The standard attainment waiting time for each partition is a dimensionless value after range normalization, where the standard attainment waiting time is the current absolute time of the system minus the recorded time when the partition reaches the drug application trigger condition. This represents the preset resistance weighting coefficient; This represents the preset time waiting weight coefficient.

[0055] The range normalization process includes: when there is a difference between the maximum and minimum values ​​of the zone airflow resistance evaluation values ​​of multiple parallel benchmark zones, the zone airflow resistance evaluation values ​​of each zone are normalized according to the range between the maximum and minimum values; when the maximum and minimum values ​​of the zone airflow resistance evaluation values ​​are equal, the corresponding values ​​of each zone are normalized. All values ​​are set to the same preset value. The range normalization of the waiting time for achieving the target is performed in the same way; when the maximum and minimum waiting times for multiple concurrently achieving the target are equal, the values ​​corresponding to each partition are... Set them all to the same preset values.

[0056] To balance prioritizing areas with high airflow resistance with preventing excessive waiting time in certain areas, those skilled in the art can allocate weight ratios according to actual needs, typically... The value range is configured to be from 0.6 to 0.8. The value range is configured to be 0.2 to 0.4, and the sum of the two is 1. By normalizing the variables, the dimensional differences between the resistance characteristics and the time characteristics are eliminated.

[0057] The control unit calculates the values ​​of each parallel target zone. The drugs are sorted in descending order to generate a drug administration sequence queue. In special cases where the overall priority values ​​are the same, the control unit will prioritize... Zones with larger values ​​are prioritized for queuing. Based on this execution sequence queue, the control unit opens the corresponding branch valves one by one to perform single-zone rotational dosing. After releasing the set dose of thiosulfate in a single zone, the control unit closes the branch valve of the current zone, marks the zone as having been dosing in the storage medium, resets or suspends its accumulated hypoxia exposure value, and prevents the system from falling into a control loop of repeatedly dosing the same zone. Subsequently, the control unit starts the thiosulfate release operation for the next zone in the queue order. This rotational execution mechanism avoids a sudden drop in total pipeline pressure caused by opening multiple dosing branches simultaneously, ensuring the accuracy of the dosing amount released in a single operation.

[0058] After the initial multi-zone rotational application of the pesticide, the system enters the closed-loop maintenance phase. The control unit continuously monitors the sulfuryl fluoride concentration and time integral value of each zone, performs targeted compensation for areas with insufficient local concentration, and performs venting operation after the overall concentration reaches the target. The specific execution process includes the following sub-steps: S51, the control unit performs pesticide concentration time-series tracking and local deviation assessment. After a single application or multi-zone rotational application, for the target zone that has been treated, the control unit sends a reset command to the corresponding measurement bypass to reopen the isolation solenoid valve of that zone, restoring the gas connection path between the probe and the sensor assembly. Since pest mortality depends not only on the transient pesticide concentration in the environment but also on the effective accumulation of concentration over time, the control unit uses the sulfuryl fluoride concentration sensor in the sensor assembly to continuously collect the real-time local sulfuryl fluoride concentration at the location of the probe in each zone, and uses a time integration calculation method to calculate the sulfuryl fluoride concentration and time integral value of each zone during the closed-loop maintenance period. The control unit calculates the sulfuryl fluoride concentration and time integral value of the i-th zone according to the following formula: ; In the formula, Indicates the first The concentration of thioyl fluoride and its time integral value in each partition during the calculation period; This indicates the initial system time after the target zone completes its first sulfuryl fluoride release operation and restores the sampling pathway; Represents the current absolute time of the system; Indicates the first Each partition The real-time concentration of sulfuryl fluoride gas measured at all times.

[0059] The control unit will calculate in real time The comparison is performed with the dynamic reference lower limit. The specific logic for generating this dynamic reference lower limit is as follows: the control unit extracts the system's preset total fumigation acceptance threshold and divides it by the planned total fumigation duration to obtain the target cumulative constant per unit time; the control unit uses the currently executed time ( minus Multiply by the target cumulative constant, and then multiply by a preset tolerance coefficient to obtain the dynamic reference lower limit that should be reached at this moment. The total fumigation acceptance threshold and the planned total fumigation time can be preset according to the target pest species, grain variety, storage space volume, target sulfuryl fluoride dosage and applicable fumigation process requirements. The tolerance coefficient is usually configured to range from 0.7 to 0.85.

[0060] The dynamic reference lower limit is used for process monitoring and local compensation judgment, and does not replace the final fumigation acceptance threshold. When monitoring detects a certain zone... When the concentration in a local area is lower than the dynamic reference lower limit at the corresponding time, the control unit determines that the concentration may be insufficient due to local leakage in the storage body, uneven gas distribution, local adsorption of the grain pile, or insufficient gas retention. Then, it generates a local compensation trigger command for the local area.

[0061] S52, the control unit performs a small-dose compensation release operation based on historical resistance characteristics. For substandard zones that receive a compensation trigger command, to ensure the supplemented agent is accurately retained in the target area, the control unit retrieves the zone airflow resistance evaluation value obtained during the zone airflow resistance detection phase from the storage medium, and matches the compensation control parameters accordingly. The target drug dose for a single compensation is typically configured based on 5% to 15% of the initial set release dose for that zone.

[0062] If the zone's airflow resistance evaluation value is higher than the preset airflow resistance classification threshold, the control unit executes a high airflow resistance compensation strategy. In embodiments where the main injection pipe is equipped with an electric pressure reducing valve, a proportional pressure regulating valve, or an equivalent pressure regulating valve, the control unit increases the output pressure setpoint of the pressure regulating valve and controls the mass flow controller and branch valves to release the compensation dose in a short-pulse manner. In embodiments where the main injection pipe is only equipped with a mass flow controller and not an independent pressure regulating valve, the control unit does not perform pressure setpoint adjustment, but releases the compensation dose by increasing the mass flow setpoint, increasing the single pulse width, increasing the number of pulses, or extending the compensation release time.

[0063] If the zone's airflow resistance evaluation value is lower than the airflow resistance grading threshold, the control unit executes a low airflow resistance compensation strategy. In embodiments where the dosing main pipe is equipped with an electric pressure reducing valve, a proportional pressure regulating valve, or an equivalent pressure regulating valve, the control unit lowers the output pressure setpoint of the pressure regulating valve and controls the mass flow controller to release the compensation dose at a lower constant flow rate. In embodiments where the dosing main pipe is only equipped with a mass flow controller and not an independent pressure regulating valve, the control unit does not perform pressure setpoint adjustment, but releases the compensation dose by at least one of reducing the mass flow setpoint, shortening the compensation release time, reducing the pulse frequency, or reducing the number of compensation releases.

[0064] To prevent the system from getting stuck in a cycle of repeated compensation for the same zone due to physical blockage around the probe or serious leakage in the silo structure, the control unit is equipped with a maximum compensation count threshold, typically set between 3 and 5 times. After each compensation operation for a zone, the control unit increments the compensation status counter for that zone. When the cumulative compensation count reaches the maximum threshold and the sulfuryl fluoride concentration and time integral value in that area are still below preset requirements, the control unit terminates the automatic compensation program for that zone and outputs a local airtightness anomaly warning signal through the human-machine interface, prompting operators to intervene and verify.

[0065] S53, the control unit performs fumigation acceptance confirmation and safety ventilation and exhaust operations. As the maintenance phase progresses, the control unit cyclically evaluates the final cumulative data of each zone. When the sulfuryl fluoride concentration and time integral value of all monitored zones in the storage space reach the system's preset total fumigation acceptance threshold, and the overall environmental airtightness maintenance time meets the process specifications, the control unit determines that the fumigation operation has met the standards. The control unit sends a global reset command to the application device, maintaining the main valve and all branch valves of the sulfuryl fluoride gas source in the de-energized and closed state, cutting off the agent source from the pipeline root.

[0066] Subsequently, the control unit initiates the safe exit procedure, activating the external ventilation and exhaust systems of the storage space and controlling the circulation system to introduce fresh outside air to physically replace and expel the residual low-oxygen mixed fumigation gas inside the storage space. During the exhaust process, the control unit continuously monitors the gas status at the exhaust vents and inside the storage space. When the residual concentration of sulfuryl fluoride inside the storage space falls below a preset safety threshold and the oxygen concentration rises back to a preset safe oxygen concentration range, the control unit determines that the environment inside the storage space meets the safe exit conditions.

[0067] Preset safety thresholds can be set according to applicable safety operating procedures, enterprise standards, or project requirements. For example, the residual concentration of sulfuryl fluoride should not exceed the set entry limit, and the oxygen concentration should not be lower than 19.5%. After the exhaust operation is completed, the control unit stops the output of the relevant actuators and puts the system into standby mode.

[0068] Wheat fumigation was carried out in a single-story warehouse with a storage volume of 3000 m³. 3 The grain pile was divided into multiple monitoring zones. Zone A was located deep within the grain pile and contained more impurities, while Zone B was located near the surface.

[0069] Control parameter settings: The preset low oxygen reference concentration is set to 4.0%, the pre-treatment trigger threshold is set to 150%·h, and the total threshold for sulfuryl fluoride fumigation acceptance is set to 150g·h / m³. 3 The correction constant is set to 0.01, and the airflow resistance grading threshold is set to 1000.

[0070] Calculation of airflow resistance evaluation value and monitoring of oxygen concentration: During nitrogen purging and short-time pulse detection, the system collects fluid characteristic parameters of zone A and zone B, and calculates them according to the formula. Calculate the evaluation value of airflow resistance in the zone.

[0071] For partition A, the system recorded a baseline pressure of 0 Pa and a peak pressure of 125 Pa. The oxygen concentration decreased from 21% to 20.4% within a preset time window, with an absolute decay rate of 0.005% / s. Substituting these values ​​into the calculation: ; Combination Figure 6The solid line represents the oxygen concentration in zone A. Due to the high calculated airflow resistance evaluation value, the oxygen concentration in this zone exhibits a gradual downward trend.

[0072] For partition B, the system recorded a baseline pressure of 0 Pa and a peak pressure of 35 Pa. The oxygen concentration decreased from 21% to 17.4% within a preset time window, with an absolute decay rate of 0.03% / s. Substituting these values ​​into the calculation: ; Combination Figure 6 The dotted line represents the oxygen concentration in zone B. Due to the low calculated airflow resistance rating, the oxygen concentration in this zone exhibits a rapid rate of decline.

[0073] Drug administration triggering and dynamic adjustment: The system continuously monitors the local environment and triggers drug administration when the cumulative value of hypoxia exposure reaches 150%·h.

[0074] For zone B, the oxygen concentration decreases more rapidly. For example... Figure 6 As indicated by the dashed line, zone B reached the pre-treatment trigger threshold in the 10th hour. At this point, the system retrieved the pre-stored zone airflow resistance evaluation value. (875). Since this value is lower than the set airflow resistance classification threshold of 1000, the system determines zone B as a low airflow resistance zone and matches and executes the constant flow slow-release mode based on this parameter. For example... Figure 6 As shown by the midpoint line, the system starts releasing thiocyanate fluoride at the 10th hour, and its local concentration rise curve is smooth.

[0075] For zone A, the oxygen concentration decreases slowly. For example... Figure 6 As shown by the solid line, zone A reached the pre-treatment trigger threshold in the 15th hour. The system then retrieved the pre-stored zone airflow resistance evaluation value. (8333). Because this value is higher than the airflow resistance classification threshold, the system matches and executes the pulse release mode, controlling the branch valves to perform periodic opening and closing actions. For example... Figure 6 As shown by the dashed line, the system starts releasing sulfuryl fluoride at the 15th hour. Due to the physical pulsation of the valve, the local concentration rise curve shows a fluctuating characteristic.

[0076] Compensation and release phase: During the maintenance phase, the system calculates the dynamic reference lower limit based on the target cumulative constant per unit time. Assuming that at the 24th hour, this dynamic reference lower limit is 40 g·h / m³. 3 The system synchronously calculates the measured sulfuryl fluoride concentration and time integral value. If the sulfuryl fluoride concentration and time integral value of zone A at this time is 32 g·h / m 3The system determines that the value is below the dynamic reference lower limit and generates a local drug replenishment trigger command. Based on the zone airflow resistance evaluation value of zone A, the control unit again invokes the high airflow resistance compensation strategy and executes small-dose release in a pulse manner until the value meets the requirements.

Claims

1. A smart control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen, characterized in that, include: Open the isolation solenoid valve to start the nitrogen circulation replacement operation, and obtain pressure change signals and oxygen concentration data of multiple zones in the grain pile through the measurement bypass; Based on the pressure change signal and the oxygen concentration data, the pressure characteristic value and oxygen concentration decay characteristic value of each zone are extracted, and the zone airflow resistance evaluation value is calculated. Read real-time oxygen concentration parameters, combine them with preset hypoxia reference concentration to calculate the cumulative hypoxia exposure value of each zone, and determine whether the cumulative hypoxia exposure value of each zone reaches the preset drug triggering threshold. When the cumulative value of hypoxia exposure in the target zone in each zone reaches the pre-treatment trigger threshold, the isolation solenoid valve corresponding to the target zone is closed and the branch valve corresponding to the target zone is opened. The sulfuryl fluoride release parameter is adjusted using the zone airflow resistance evaluation value corresponding to the target zone, and a sulfuryl fluoride release operation is performed on the target zone. Monitor the concentration and time integral value of sulfuryl fluoride in the target zone, determine and execute local compensation release operation, and start ventilation and exhaust operation after meeting the process setting specifications.

2. The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen gas according to claim 1, characterized in that, The step of acquiring pressure change signals and oxygen concentration data of multiple zones within the grain pile through a measurement bypass includes: Send an action command to the interlock switching valve group located between the main application pipe and the air inlet pipe, so that the main application pipe is temporarily connected to the nitrogen source and the main application pipe is isolated from the sulfuryl fluoride source. A transient opening command is sent to the branch valve corresponding to any one of the multiple partitions, causing the branch valve to perform a short-term opening and closing action to inject nitrogen into any one of the partitions through the dosing branch; The peak data of the pressure response and the pressure recovery time are captured by a micro-pressure sensor, and the captured peak data and the pressure recovery time are recorded as part of the pressure change signal.

3. The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen gas according to claim 1, characterized in that, The steps of extracting the pressure characteristic values ​​and oxygen concentration attenuation characteristic values ​​of each zone and calculating the zone airflow resistance evaluation value include: The initial ambient pressure is used as the reference pressure, and the pressure value is continuously monitored and the maximum pressure value is extracted as the pressure peak. Extract time-series data of oxygen concentration within a preset time window, and obtain the absolute rate of decrease of local oxygen concentration over time by calculating the ratio of the change in oxygen concentration to the corresponding time difference. The difference between the peak pressure and the reference pressure is used as the divisor, and the sum of the absolute rate of decrease of the local oxygen concentration over time and the correction constant is used as the divisor. The evaluation value of the airflow resistance of the zone is obtained by division.

4. The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen gas according to claim 1, characterized in that, The step of reading real-time oxygen concentration parameters and calculating the cumulative hypoxia exposure value for each zone in combination with a preset hypoxia reference concentration includes: The collected real-time oxygen concentration parameter is dynamically compared with the preset low oxygen reference concentration. When the real-time oxygen concentration parameter is lower than the preset low oxygen reference concentration, the low oxygen exposure time series tracking time is started. The difference between the preset hypoxia reference concentration and the real-time oxygen concentration parameter is obtained. The difference is multiplied by the condition control coefficient to obtain a product. The product is integrated and accumulated over time to obtain the cumulative value of hypoxia exposure.

5. The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen gas according to claim 4, characterized in that, The step of integrating and accumulating the product over time includes: When the preset low oxygen reference concentration is greater than the real-time oxygen concentration parameter, the condition control coefficient is set to one, and normal difference accumulation is performed. When the real-time oxygen concentration parameter is greater than or equal to the preset low oxygen reference concentration, the condition control coefficient is zero, and the integral accumulation operation is paused. When the duration of the condition control coefficient being zero exceeds the reset time threshold, the accumulated value of hypoxia exposure will be cleared to zero.

6. The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen gas according to claim 1, characterized in that, The step of adjusting the sulfuryl fluoride release parameter using the corresponding zone airflow resistance evaluation value includes: The evaluation value of the airflow resistance of the target zone is compared with the airflow resistance grading threshold. If the zone airflow resistance evaluation value is higher than or equal to the airflow resistance grading threshold, the sulfuryl fluoride release intensity is increased by adjusting the sulfuryl fluoride release parameter, and the branch valve is controlled to perform periodic opening and closing actions to form intermittent airflow release. If the evaluation value of the zoned airflow resistance is lower than the airflow resistance grading threshold, the sulfuryl fluoride release intensity is reduced by adjusting the sulfuryl fluoride release parameter, and the branch valve is kept in a continuously open state or a low-frequency open state. The sulfuryl fluoride release parameters include at least one of the following: mass flow rate, release pressure, release duration, valve opening and closing cycle, pulse width, number of pulse releases, and compensation dose.

7. The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen gas according to claim 1, characterized in that, In the step of performing the sulfuryl fluoride release operation on the target partition, when there are multiple concurrent target partitions, the step of allocating the control order includes: Extract the airflow resistance evaluation value and the achievement timestamp of the multiple concurrent target partitions; The dimensionless value of the partitioned airflow resistance evaluation value after range normalization is multiplied by the resistance weight coefficient to obtain the first product. The dimensionless value of the compliance waiting time calculated from the compliance timestamp after range normalization is multiplied by the time waiting weight coefficient to obtain the second product. The first product and the second product are added together to obtain a comprehensive priority value. The comprehensive priority value is then sorted in descending order to generate a drug application execution sequence queue. The corresponding branch valves are opened one by one according to the drug application execution sequence queue to perform single-zone rotational drug application.

8. The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen gas according to claim 1, characterized in that, The steps for determining and performing the local compensation release operation include: Calculate the integral of the real-time concentration of sulfuryl fluoride in the target partition over time during the period of closed maintenance, and obtain the sulfuryl fluoride concentration and time integral value. Extract the total fumigation acceptance threshold and divide it by the planned total fumigation duration to obtain the target cumulative constant per unit time. Multiply the current execution time by the target cumulative constant and then by the tolerance coefficient to obtain the dynamic reference lower limit. When the concentration of sulfuryl fluoride and the time integral value are lower than the corresponding dynamic reference lower limit, a local compensation trigger command is generated for the non-compliant zone and the local compensation release operation is started.

9. The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen gas according to claim 8, characterized in that, The steps for initiating the local compensation release operation include: Retrieve the airflow resistance evaluation value of the zone corresponding to the zone that did not meet the standard; If the evaluation value of the airflow resistance of the zone is higher than the preset airflow resistance grading threshold, the compensation release intensity is increased, and the branch valve is controlled to release the compensation dose in a short pulse manner. If the zoned airflow resistance evaluation value is lower than the preset airflow resistance grading threshold, the compensation release intensity is reduced, and the compensation dose is released using a lower flow rate constant flow. After each compensation action is performed, the compensation status counter is incremented by one. When the cumulative number of compensations reaches the maximum compensation number threshold and the sulfuryl fluoride concentration and time integral value are still lower than the dynamic reference lower limit, the automatic compensation program is terminated and an abnormal warning signal is output. The compensated release intensity is achieved by adjusting at least one of the following: mass flow rate, release pressure, compensated release time, pulse width, pulse number, and compensated dose.

10. A smart control system for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen, characterized in that, The intelligent control method for synergistic reduction of fumigation by sulfuryl fluoride and nitrogen as described in any one of claims 1 to 9 includes: Gas source device, including nitrogen gas source and sulfuryl fluoride gas source; A circulation device, connected to the internal storage space where grain piles are stored, includes a circulation fan and an air inlet pipe connected to the nitrogen source; The application device includes a main application pipe connected to the sulfuryl fluoride gas source, and multiple application branches branching from the main application pipe. The end of each application branch is connected to a probe, and a branch valve is provided on each application branch. The main application pipe is equipped with a mass flow controller and optionally a pressure regulating valve. An interlocking switching valve assembly is installed between the main application pipe and the air inlet pipe; The sensor assembly includes a micro-pressure sensor, an oxygen concentration sensor, and a sulfuryl fluoride concentration sensor; The measurement bypass has one end connected to the pipe section where the probe is located and the other end connected to the sensor assembly. An isolation solenoid valve is provided on the measurement bypass. The control unit establishes communication connections with the main valve of the nitrogen gas source, the main valve of the sulfuryl fluoride gas source, the circulating fan, the branch valve, the interlock switching valve group, the mass flow controller, the isolation solenoid valve, and the sensor assembly, respectively, and establishes a communication connection with the pressure regulating valve when the main injection pipe is equipped with the pressure regulating valve.

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