An adaptive environmental variable high-precision oxygen injection system and a method of using the same

Abstract

This invention provides a high-precision oxygen injection system and its usage method that adapts to environmental variables, improving the control accuracy, response speed, and stability of the oxygen injection system under dynamic environments. The system includes a gas source processing unit, a staged injection unit, an environmental sensing unit, and an intelligent control unit. The staged injection unit is connected to the output of the gas source processing unit and has a parallel-connected high-flow-rate main gas path and a low-flow-rate precision regulating gas path. The environmental sensing unit is located at least in the stable section and the test section of the closed-loop fluid equipment. The intelligent control unit is equipped with a feedforward control module that calculates the total oxygen demand based on real-time acquired equipment total pressure, total temperature parameters, and liquid nitrogen injection data using a corrected gas state equation. A closed-loop compensation module acquires monitoring data from the environmental sensing unit and uses an overdamped PID algorithm to compensate for the feedforward control residual. The injection module responds to the liquid nitrogen injection signal, controls the high-flow-rate main gas path, and performs counter-current control.

Description

Technical Field

[0001] This invention relates to the field of gas injection control technology, specifically to a high-precision oxygen injection system and its application method that is suitable for closed-loop fluid system test environments and has the ability to adapt to environmental variables. It is particularly suitable for scenarios such as aerospace testing and precision control of industrial gases. Background Technology

[0002] Traditional oxygen injection systems have the following problems in dynamic environments (such as closed-loop fluid system tests): Poor environmental adaptability: It cannot sense pressure, temperature and liquid nitrogen injection disturbances in real time. In particular, traditional systems cannot predict the dilution effect of liquid nitrogen injection on oxygen concentration in real time, resulting in compensation delay (especially when the liquid nitrogen flow rate suddenly increases), resulting in large oxygen concentration control error (usually >±10%). Low flow regulation accuracy: A single gas path is difficult to cover a wide range of flow requirements (such as 0.1-1400 Nm³ / h), and the low flow range is easily affected by the nonlinearity of valve components; Response lag: Oxygen compensation is delayed (>5 seconds) during liquid nitrogen injection countermeasures, which can easily cause oxygen concentration overshoot; High safety risks: Lack of multi-level pressure and oxygen concentration interlock protection, resulting in insufficient system stability. Summary of the Invention

[0003] The purpose of this invention is to provide a high-precision oxygen injection system that adapts to environmental variables and its usage method, which effectively solves the above-mentioned technical bottlenecks by adopting multi-module collaborative control and intelligent algorithm optimization.

[0004] The embodiments of the present invention are implemented as follows: A high-precision oxygen injection system that adapts to environmental variables, comprising: The gas source processing unit includes a dew point detector, a dual gas source switching mechanism, and a pressure pretreatment module; The staged injection unit is connected to the output end of the gas source processing unit. The staged injection unit has a high-flow main gas path and a low-flow precision regulating gas path arranged in parallel. The low-flow precision regulating gas path contains at least three independent and controllable regulating branches. The environmental sensing unit integrates a pressure sensor, a temperature sensor, an oxygen analyzer, and a liquid nitrogen injection monitoring module. The environmental sensing unit is located at least at the rear end of the stable section and the rear end of the test section of the closed-loop fluid equipment. The intelligent control unit is equipped with: The feedforward control module calculates the total oxygen demand based on real-time acquired equipment total pressure, total temperature parameters, and liquid nitrogen injection data, using the gas state equation combined with the modified equation or simulation model value. The closed-loop compensation module acquires monitoring data from the environmental sensing unit, uses an overdamped PID algorithm to compensate for the feedforward control residual, and controls the small-flow precision regulating air path to perform precise compensation. Accompanying the injection module, it responds to the liquid nitrogen injection signal to control the high-flow main gas path and executes counter-current control; The safety interlock unit includes an emergency quick-cut valve assembly and an overpressure relief device.

[0005] In a preferred embodiment of the present invention, the above-described feedforward control module performs the following: Calculate the total number of moles of gas n in the equipment based on PV=nRT; The required number of oxygen molecules Δn is calculated based on the target oxygen content (ppm) value obtained by the environmental sensing unit: Δn = (n × target ppm) / (10^6 - target ppm). Generate feedforward injection commands to control the injection volume = K × Δn, where K is an adjustable coefficient of 0.8-0.95; The closed-loop compensation module is activated after the injection is completed.

[0006] In a preferred embodiment of the present invention, the above-mentioned feedforward control module and closed-loop compensation module have: A dual-mode regulation mechanism is used, employing a parameter set with a proportional coefficient P∈[0.5,1.5] and an integral time Ti≥30s during the high-flow phase; During low-flow phases, switch to the parameter set P∈[0.1,0.3], Ti∈[60,120s]; The differential action is limited to D≤0.05Ti.

[0007] In a preferred embodiment of the present invention, the accompanying injection module includes: The liquid nitrogen flow prediction submodule acquires the liquid nitrogen valve position signal in real time via the Modbus protocol. The dynamic compensation algorithm submodule establishes the transfer function between the liquid nitrogen injection amount Q_N2(t) and the oxygen compensation amount ΔQ_O2(t): ΔQ_O2(t) = α∫Q_N2(t)dt + βdQ_N2(t) / dt, Among them, α=0.78±0.05, β=2.3±0.2; The actuator initiates pre-compensation injection 2-5 seconds before liquid nitrogen injection.

[0008] In a preferred embodiment of the present invention, the above-mentioned staged injection unit includes: The high-flow main gas path is equipped with a DN80 pipeline and a combination of valves consisting of a first pneumatic regulating valve, a first vortex flow meter, and a first pneumatic valve, with a flow range of 800-1400 Nm³ / h; The small-flow precision regulating gas circuit has three parallel branches, each configured as follows: First branch: DN32 pipeline equipped with a second pneumatic regulating valve, a 0.1% accuracy mass flow meter and a second pneumatic valve, with a flow range of 10-50 Nm³ / h; Second branch: DN20 pipeline equipped with piezoelectric regulating valve and first flow control valve with accuracy ±1% FS, flow range 5-20Nm³ / h; The third branch: a DN10 pipeline equipped with a stepper motor driven needle valve and a second flow control valve with an accuracy of ±0.5% FS, with a flow range of 0.1-5 Nm³ / h.

[0009] In a preferred embodiment of the present invention, the above-mentioned safety interlocking unit includes: Three-stage pressure protection mechanism: the first stage triggers an alarm at 1.2MPa, the second stage activates the quick-cut valve at 1.3MPa, and the third stage opens the safety valve at 1.5MPa; Oxygen concentration dual threshold protection: When the oxygen content ppm in the equipment exceeds the set value by 20%, a first-level alarm is triggered; when it exceeds 50%, an emergency purging is performed.

[0010] In a preferred embodiment of the present invention, the above-mentioned intelligent control unit is further configured with: The equipment volume self-learning module uses data from multiple injection tests to deduce the actual volume value V'=V+ΔV; The dynamic equation correction module extends the ideal gas equation to: (P+a(n / V)^2)(V-nb) = nRT, where a and b are van der Waals correction coefficients.

[0011] In a preferred embodiment of the present invention, the above-mentioned environmental sensing unit further includes: A redundant temperature detection array, with at least 5 sets of PT100 sensors arranged along the axis from the stable section to the test section of the closed-loop fluid equipment; The pressure fluctuation compensation module uses a sliding time window algorithm to calculate the dynamic average pressure value. The pressure data processing uses the sliding time window algorithm to take the weighted average of the data from the most recent 30 seconds. P_avg=Σ(w_i×P_i) / Σw_i, where w_i=1-0.03×(30-t_i).

[0012] A method for using a high-precision oxygen injection system that adapts to environmental variables includes the following steps: The environmental sensing unit collects data from pressure sensors, temperature sensors, and liquid nitrogen injection monitoring modules within the closed-loop fluid equipment and calculates the total oxygen molecule demand. The feedforward control module calculates the current total number of gas moles using PV=nRT based on real-time total pressure, total temperature and liquid nitrogen data, calculates the total oxygen molecule demand in combination with the target ppm value, generates feedforward injection commands with a coefficient of 0.8-0.95, and transmits them to the accompanying injection module to control the high-flow main gas circuit valves to execute the accompanying injection. Perform closed-loop compensation: Use an overdamped PID algorithm to compensate for the feedforward residual. Use the parameter set P∈[0.5,1.5] and Ti≥30s during the high flow rate stage, and switch to the parameter set P∈[0.1,0.3] and Ti∈[60,120s] during the low flow rate stage. When the required flow rate is 30-50 Nm³ / h, the first branch mass flow meter and the second branch combined valve are used for regulation. When the required flow rate is 10-30 Nm³ / h, the combined valves of the first and third branches are used for regulation. When the required flow rate is 5-10 Nm³ / h, the combined valves of the second and third branches are used for regulation. When the required flow rate is <5Nm³ / h, the third branch stepper motor needle valve and the high-precision second flow control valve are activated for fine-tuning. Traffic overlap control is performed during branch switching to ensure that the total traffic fluctuation is less than ±0.5%.

[0013] In a preferred embodiment of the present invention, the above-mentioned feedforward control steps specifically include: Obtain the current pressure P and temperature T, and calculate the corrected volume according to V'=V+ΔV, where ΔV is obtained by back-calculation through multiple injection tests; The total number of moles of the actual gas, n, is calculated using the modified gas equation (P + a(n / V)^2)(V - nb) = nRT. Calculate the required number of oxygen molecules Δn = (n × target ppm) / (10^6 - target ppm); The generated feedforward injection rate = K × Δn, where K = 0.8 - 0.95; After the feedforward injection is completed, the closed-loop compensation is initiated. During the injection process, the dynamic compensation coefficients α and β are corrected in real time according to the ambient temperature: when 220K < T < 334K, α = 0.78 × (1 + 0.002(T - 273)); when 105K < T ≤ 220K, β = 2.3 × (1 - 0.0015(T - 273)).

[0014] The beneficial effects of the embodiments of the present invention are: 1. Dynamic Sensing and Precise Control of Environmental Parameters: Employing multi-source data fusion and integrating pressure, temperature, and liquid nitrogen injection monitoring modules, real-time sensing of environmental variables within the closed-loop fluid system is achieved, ensuring the dynamic adaptability of total oxygen demand calculation and improving error compensation response speed by over 30%. A volumetric self-compensation mechanism is used, employing a modified gas equation (a variant of the van der Waals equation) and a volumetric self-learning algorithm (V'=V+ΔV) to eliminate the impact of equipment volume errors on mole count calculation, improving the total oxygen prediction accuracy to ±0.8%. 2. Dual-mode collaborative control improves response efficiency: A feedforward-feedback closed-loop collaborative control is adopted: feedforward control rapidly generates injection commands (K=0.8-0.95) based on real-time parameters (P, T, liquid nitrogen), while closed-loop compensation eliminates residuals through an overdamped PID algorithm (parameter segment switching), reducing overall control response time by 40% and achieving a steady-state error of <±0.3%; temperature-adaptive dynamic compensation is employed, with dynamic correction coefficients α and β (α=0.78×(1+0.002ΔT), β=2.3×(1-0.0015ΔT)) during injection, adapting to a wide temperature range of 105K~334K, improving compensation accuracy by 25%.

[0015] 3. Hierarchical dynamic adaptation enables wide-range precision regulation: Employing intelligent multi-branch combinations: 30-50 Nm³ / h: First branch (mass flow meter) + second branch (piezoelectric valve) combination, balancing flow range and response speed; 10-30 Nm³ / h: First branch + third branch (stepper motor needle valve) collaboration, achieving smooth transition at medium and low flow rates; 5-10 Nm³ / h: Second branch + third branch combination, reducing nonlinear errors at low flow rates; <5 Nm³ / h: Third branch needle valve + high-precision MFC fine-tuning, achieving an accuracy of ±0.1%. Simultaneously, flow overlap control technology is adopted, using a flow overlap transition strategy during branch switching, suppressing total flow fluctuations to <±0.5%, avoiding step interference.

[0016] 4. Enhanced Safety and Stability: Employs graded pressure protection: a three-level interlock of 1.2MPa alarm, 1.3MPa quick-cut valve action, and 1.5MPa relief, reducing system overpressure risk by 90%; adopts dual-threshold oxygen concentration management, with a 20% over-threshold warning and a 50% emergency purging to prevent the risk of explosion in oxygen-rich environments; employs an anti-saturation PID mode: automatically suppresses integral saturation (I_new=I_old×exp(-Δt / τ)) when pressure fluctuations >0.5% / s, avoiding control instability.

[0017] 5. Intelligent and Long-Term Reliability: The injection volume is optimized through volumetric self-learning: ΔV = Σ(Δn measured - Δn theoretical) / (Δn theoretical / V) × 0.2 is derived from injection test data to dynamically correct system volume deviation, improving long-term stability by 50%; Redundant temperature detection: 5 sets of PT100 sensor arrays + sliding time window algorithm (P_avg = Σ(w_i × P_i) / Σw_i), achieving data reliability of 99.9%; 6. Economic benefits and applicability: Energy consumption optimization: The pre-adjustment design with a feedforward injection coefficient K=0.8-0.95 reduces closed-loop compensation energy consumption by 15-20%; Wide operating condition compatibility: Covering a flow range of 0.1-1400 Nm³ / h, it is suitable for various scenarios such as closed-loop fluid system testing and semiconductor manufacturing; Reduced maintenance costs: The staged branch design extends the service life of precision valves (such as DN10 needle valves) by more than 30%.

[0018] In summary, this invention achieves high precision (±0.3%), wide range (0.1-1400 Nm³ / h), fast response (<1s), and high reliability (failure rate <0.01%) of the oxygen injection system in complex environments through the full-chain coordination of environmental perception, feedforward prediction, closed-loop feedback compensation, hierarchical execution, and safety protection. It is particularly suitable for high-end fields such as aerospace closed-loop fluid system testing and semiconductor process gas control. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a structural block diagram of a high-precision oxygen injection system according to an embodiment of the present invention; Figure 2 This is a control block diagram of the intelligent control unit according to an embodiment of the present invention; Figure 3 This is a flowchart illustrating the usage method of the high-precision oxygen injection system with adaptive environmental variables according to an embodiment of the present invention. Icons: Gas source processing unit 105; Staged injection unit 120; High-flow main gas path 121; Low-flow precision regulating gas path 122; Environmental sensing unit 130; Intelligent control unit 140; Feedforward control module 141; Closed-loop compensation module 142; Accompanying injection module 143; Safety interlock unit 144. Detailed Implementation

[0021] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0023] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0024] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0025] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0026] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software, in one or more hardware modules or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0027] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0028] First Embodiment Please see Figure 1 and Figure 2 This embodiment provides a high-precision oxygen injection system that adapts to environmental variables, comprising: The gas source processing unit 105 includes a dew point detector, a dual gas source switching mechanism and a pressure pre-processing module. The pressure pre-processing module is used to overcome the problem of large pressure range under working conditions. It includes an automatic pressure regulating valve and a diaphragm pneumatic regulating valve connected in sequence. The automatic pressure regulating valve stabilizes the pressure difference across the gas path based on changes in the total pressure of the closed-loop fluid equipment, thereby stabilizing the airflow velocity. Controlling and achieving a stable pressure difference is the first step in controlling the gas flow rate. Secondly, to further improve the control capability of the gas flow rate within the pipeline, the pressure pretreatment module also adds a diaphragm-type pneumatic regulating valve to the pipeline. This valve features a fast control response and is used to actively regulate the gas flow rate within the pipeline, improving the accuracy of oxygen molecule injection and maintaining the pressure difference at a constant 0.4 MPa.

[0029] The staged injection unit 120 is connected to the output end of the gas source processing unit 105. The staged injection unit 120 has a high-flow main gas path 121 and a low-flow precision regulating gas path 122 arranged in parallel. The low-flow precision regulating gas path includes at least three independent and controllable regulating branches. Even though an automatic pressure regulating valve and a diaphragm pneumatic regulating valve are designed in this embodiment to precisely control the gas flow rate in the pipeline, the absolute value of the pressure in the pipeline is still a variable, which will still affect the air density in the pipeline and the flow rate of injected oxygen molecules. This embodiment also includes an environmental sensing unit 130, which integrates a pressure sensor, a temperature sensor, an oxygen analyzer, and a liquid nitrogen injection monitoring module. The environmental sensing unit 130 is located at least at the rear end of the stable section and the rear end of the test section of the closed-loop fluid equipment. Intelligent control unit 140, configured with: The feedforward control module 141 calculates the total oxygen molecule demand based on the real-time acquired equipment total pressure, total temperature parameters, and liquid nitrogen injection data, using the gas state equation and combining the modified equation or simulation mode value. The closed-loop compensation module 142 acquires the monitoring data from the environmental sensing unit 130, uses an overdamped PID algorithm to compensate for the feedforward control residual, and controls the small flow precision regulating gas path to perform precise compensation. Accompanying the injection module 143, it responds to the liquid nitrogen injection signal to control the high-flow main gas path 121 and executes counter-current control; Safety interlock unit 144 includes an emergency quick-cut valve assembly and an overpressure relief device.

[0030] In traditional closed-loop fluid control systems, the response lag to random liquid nitrogen injection disturbances stems from the system's inability to predict the dilution effect of liquid nitrogen injection on oxygen concentration in real time. This leads to compensation delays (especially during sudden increases in liquid nitrogen flow rate) and excessive oxygen concentration fluctuations. This directly results in the following system defects: reliance on single feedback control, resulting in insufficient response speed; lack of a dynamic transfer function between liquid nitrogen flow rate and oxygen compensation, leading to mismatch in hedging; and insufficient gas supply capacity and significant compensation lag in extreme scenarios (liquid nitrogen flow rate > 1400 Nm³ / h).

[0031] To address the aforementioned issues, this embodiment employs automatic accompanying injection to overcome liquid nitrogen interference. The main strategy involves reading liquid nitrogen injection data, such as the liquid nitrogen injection flow rate and injection duration, to control the corresponding air flow rate and duration. Simultaneously, the high-flow-rate main gas path 121 responds promptly, quickly stabilizing the excessive fluctuations in oxygen concentration and thus achieving a stable system ppm value.

[0032] Specifically, in this embodiment, the feedforward control module 141 performs the following steps: Calculate the total number of moles of gas n in the equipment based on PV=nRT; The required number of oxygen molecules Δn is calculated based on the target oxygen content (ppm) value obtained by the environmental sensing unit 130: Δn = (n × target ppm) / (10^6 - target ppm). Generate feedforward injection commands to control the injection volume = K × Δn, where K is an adjustable coefficient of 0.8-0.95; After the injection is completed, the closed-loop compensation module 142 is activated.

[0033] In this embodiment, for a general feedforward control algorithm, both a feedforward control module 141 and a closed-loop compensation module 142 are included. The closed-loop compensation module 142 employs PID feedback control to form a closed loop. This can solve the overshoot risk under traditional unidirectional control. For example, traditional PID parameters (critical damping or underdamping) are prone to overshoot (e.g., overshoot > 5%) in unidirectional injection systems, and cannot be corrected by reverse operation. This embodiment improves the integral saturation suppression mechanism by adopting an overdamped PID parameter group; it also improves the feedforward-feedback collaborative strategy, implementing segmented control of the injection volume (e.g., 80%-95%) for dynamic optimization. Specifically, the feedforward control module 141 and the closed-loop compensation module 142 have the following features: A dual-mode regulation mechanism is used, employing a parameter set with a proportional coefficient P∈[0.5,1.5] and an integral time Ti≥30s during the high-flow phase; During low-flow phases, switch to the parameter set P∈[0.1,0.3], Ti∈[60,120s]; The differential action is limited to D≤0.05Ti.

[0034] During the trial operation of the closed-loop fluid equipment, liquid nitrogen may be automatically replenished into the system at any time. This replenishment dilutes the oxygen content (ppm). When performing stable control of the oxygen content (ppm), this random disturbance must be considered. In this embodiment, accompanying injection is used to overcome this defect. The accompanying injection module 143 specifically includes: The liquid nitrogen flow prediction submodule acquires the liquid nitrogen valve position signal in real time via the Modbus protocol. The dynamic compensation algorithm submodule establishes the transfer function between the liquid nitrogen injection amount Q_N2(t) and the oxygen compensation amount ΔQ_O2(t): ΔQ_O2(t) = α∫Q_N2(t)dt + βdQ_N2(t) / dt, Among them, α=0.78±0.05, β=2.3±0.2; The actuator initiates pre-compensation injection 2-5 seconds before liquid nitrogen injection to overcome the liquid nitrogen counter-lag.

[0035] In this embodiment, the accompanying injection module 143 (ΔQ_O2=α∫Q_N2dt+βdQ_N2 / dt) + pre-compensation mechanism is adopted, with hedging response time ≤2 seconds and fluctuation <±1%.

[0036] The wide range of test operating pressures will affect the accuracy of controlling the oxygen injection rate. For example, the pressure variation within the closed-loop fluid equipment is between 0.1 and 0.4 MPa, while the initial outlet pressure of the air source is 1 MPa. If the piping system connecting the air source and the closed-loop fluid equipment is not pressure-managed, the pressure difference between the two ends of the pipeline connecting the air source and the closed-loop fluid equipment will vary (0.6-0.9 MPa) as the test operating conditions change.

[0037] Because the gas velocity inside the pipe is proportional to the pressure difference between the two ends of the pipe (refer to the Pitot tube velocity calculation formula V=K). (K is the correction parameter, ΔP is the pressure difference, and ρ is the gas density). If the pressure difference between the two ends of the pipeline is variable, it is not easy to obtain a stable gas flow rate. Unstable gas flow rate leads to unstable gas flow rate, which is detrimental to controlling the injection accuracy. In this embodiment, a staged injection method is adopted to overcome the above defects. The staged injection unit 120 includes: The high-flow main air passage 121 is equipped with a DN80 pipeline and a combination of valves consisting of a first pneumatic regulating valve, a first vortex flow meter, and a first pneumatic valve, with a flow range of 800-1400 Nm³ / h. The small-flow precision regulating gas path 122 is equipped with three parallel branches, each configured as follows: First branch: DN32 pipeline equipped with a second pneumatic regulating valve, a 0.1% accuracy mass flow meter and a second pneumatic valve, with a flow range of 10-50 Nm³ / h; Second branch: DN20 pipeline equipped with piezoelectric regulating valve and first flow control valve with accuracy ±1% FS, flow range 5-20Nm³ / h; The third branch: a DN10 pipeline equipped with a stepper motor driven needle valve and a second flow control valve with an accuracy of ±0.5% FS, with a flow range of 0.1-5 Nm³ / h.

[0038] In a preferred embodiment of the present invention, the safety interlocking unit 144 includes: Three-stage pressure protection mechanism: the first stage triggers an alarm at 1.2MPa, the second stage activates the quick-cut valve at 1.3MPa, and the third stage opens the safety valve at 1.5MPa; Oxygen concentration dual threshold protection: When the oxygen content ppm in the equipment exceeds the set value by 20%, a first-level alarm is triggered; when it exceeds 50%, an emergency purging is performed.

[0039] The core issue regarding the estimation error of gas loss caused by system depressurization lies in the fact that traditional models assume a closed system and ignore gas loss during the depressurization process, leading to a deviation in the calculation of the total oxygen molecules (error rate > 15%). Furthermore, existing systems lack integrated dynamic volume correction algorithms (such as V' = V + ΔV), causing the ideal gas equation (PV = nRT) to fail; simultaneously, the lack of a real-time monitoring module for depressurization events prevents synchronous updates to the total gas loss model. Based on these deficiencies, this intelligent control unit 140 is also equipped with: The equipment volume self-learning module uses data from multiple injection tests to deduce the actual volume value V'=V+ΔV; The dynamic equation correction module extends the ideal gas equation to: (P+a(n / V)^2)(V-nb) = nRT, where a and b are van der Waals correction coefficients.

[0040] The dynamically corrected ideal gas calculation method can also overcome the deviation between the traditional ideal gas model and the actual operating conditions. Since the traditional ideal gas model does not take into account the intermolecular forces, the volume estimation error (ΔV is not corrected) leads to a deviation of >10% in the feedforward control quantity.

[0041] In this embodiment, the accuracy of calculating the total oxygen molecule demand is improved by introducing modified models such as the van der Waals equation and combining them with a volume self-learning mechanism (such as the ΔV back-calculation algorithm), while the model has good long-term adaptability.

[0042] In this embodiment, the environment sensing unit 130 further includes: A redundant temperature detection array, with at least 5 sets of PT100 sensors arranged along the axis from the stable section to the test section of the closed-loop fluid equipment; The pressure fluctuation compensation module uses a sliding time window algorithm to calculate the dynamic average pressure value. The pressure data processing uses the sliding time window algorithm to take the weighted average of the data from the most recent 30 seconds. P_avg=Σ(w_i×P_i) / Σw_i, where w_i=1-0.03×(30-t_i).

[0043] In summary, the high-precision oxygen injection system that adapts to environmental variables specifically addresses the technical deficiencies of existing closed-loop fluid systems, significantly improving the control accuracy, response speed, and stability of the oxygen injection system in dynamic environments. It is particularly suitable for complex scenarios such as high-precision closed-loop fluid system testing.

[0044] Second Embodiment This embodiment, based on the first embodiment, further explains some key details of its usage method. This embodiment provides a method for using a high-precision oxygen injection system that adapts to environmental variables, which includes the following steps. Please refer to [link to relevant documentation]. Figure 3 : The environmental sensing unit 130 collects data from the pressure sensor, temperature sensor, and liquid nitrogen injection monitoring module within the closed-loop fluid equipment, and calculates the total oxygen molecule demand through the feedforward control module. Based on real-time total pressure, total temperature and liquid nitrogen data, the feedforward control module 141 calculates the current total number of gas moles using the corrected (P+a(n / V)^2)(V-nb)=nRT, calculates the total oxygen molecule demand in combination with the target ppm value, generates a feedforward injection command with a coefficient of 0.8-0.95, and transmits it to the accompanying injection module 143 to control the valve of the high-flow main gas path 121 to perform accompanying injection; Perform closed-loop compensation: Use an overdamped PID algorithm to compensate for the feedforward residual. Use the parameter set P∈[0.5,1.5] and Ti≥30s during the high flow rate stage, and switch to the parameter set P∈[0.1,0.3] and Ti∈[60,120s] during the low flow rate stage. When the required flow rate is 30-50 Nm³ / h, the first branch mass flow meter and the second branch combined valve are used for regulation. When the required flow rate is 10-30 Nm³ / h, the combined valves of the first and third branches are used for regulation. When the required flow rate is 5-10 Nm³ / h, the combined valves of the second and third branches are used for regulation. When the required flow rate is <5Nm³ / h, the third branch stepper motor needle valve and the high-precision second flow control valve are activated for fine-tuning. Traffic overlap control is performed during branch switching to ensure that the total traffic fluctuation is less than ±0.5%.

[0045] In this embodiment, the oxygen staged injection unit 120 employs a parallel arrangement of a high-flow-rate main gas path 121 and a low-flow-rate precision regulating gas path 122. The low-flow-rate precision regulating gas path includes at least three independently controllable regulating branches, each equipped with different pipeline valves to overcome the airflow instability caused by system pressure fluctuations. The core issue is that changes in pipeline differential pressure (0.6-0.9 MPa) cause gas velocity fluctuations (refer to V=K√(2ΔP / ρ)), resulting in a decrease in flow control accuracy (±5% or more). In this embodiment, by configuring a pressure stabilizing valve or a dynamic differential pressure control module, the influence of operating pressure on the flow velocity is significantly reduced; the use of multiple valves overcomes the problem of insufficient response speed (>1s) of traditional pneumatic regulating valves, which cannot quickly suppress flow fluctuations.

[0046] Because the relationship between ppm and oxygen quantity is nonlinear in closed-loop fluid equipment under varying operating conditions, the core problem lies in the fact that existing systems use ppm as a single control variable, ignoring the impact of temperature and pressure changes on the number of oxygen molecules. This leads to a tenfold difference in oxygen injection quantity for the same ppm deviation (e.g., 115kPa / 334K vs. 450kPa / 105K). This directly results in traditional closed-loop fluid systems failing to convert ppm into a difference in oxygen mass / molecule number, causing a disconnect between the control strategy and the physical quantity; and lacking a temperature-pressure coupled compensation algorithm, they are unable to dynamically correct the control quantity.

[0047] To address the aforementioned issues, the feedforward control steps in this embodiment further modify the oxygen calculation method and incorporate a temperature-pressure coupling compensation algorithm, specifically including: Obtain the current pressure P and temperature T, and calculate the corrected volume according to V'=V+ΔV, where ΔV is obtained by back-calculation through multiple injection tests; The total number of moles of the actual gas, n, is calculated using the modified gas equation (P + a(n / V)^2)(V - nb) = nRT. Calculate the required number of oxygen molecules Δn = (n × target ppm) / (10^6 - target ppm); The generated feedforward injection rate = K × Δn, where K = 0.8 - 0.95; After the feedforward injection is completed, the closed-loop compensation is initiated. During the injection process, the dynamic compensation coefficients α and β are corrected in real time according to the ambient temperature: when 220K < T < 334K, α = 0.78 × (1 + 0.002(T - 273)); when 105K < T ≤ 220K, β = 2.3 × (1 - 0.0015(T - 273)).

[0048] Simultaneously, the feedforward control step also overcomes density errors caused by pipeline pressure variations. For example, existing flow meters in closed-loop fluid equipment do not consider the impact of absolute pressure changes on gas density, leading to errors in mass flow rate calculation (e.g., density error >30% at 0.4 MPa). This feedforward control step calculates mass flow rate instead of traditional volumetric flow rate and integrates a real-time density compensation algorithm, making the calculated oxygen content requirement more accurate. During the calculation process, a multi-parameter (P, T) fusion flow correction module is used for real-time correction.

[0049] Third Embodiment This embodiment uses a closed-loop fluid system experiment as an example to illustrate the system operation flow and calculation process: Initialization: Start the gas source processing unit 105, switch the dual gas sources to qualified gas sources, and pre-process the pressure to 1.0MPa; Environmental perception: Obtain the steady-state pressure P=0.95MPa, T=300K, and the liquid nitrogen injection rate Q_N2=200 Nm³ / h; Feedforward calculation: Corrected volume V' = 50 m³ (ΔV = 0.5 m³); The total number of moles is calculated as n = (P × V') / (RT) = 1950 mol; Target oxygen concentration ppm = 5000, Δn = (1950 × 5000) / (10 6 -5000) = 9.95 mol; Feedforward injection rate = 0.9 × 9.95 = 8.96 mol (corresponding to oxygen flow rate of 32.1 Nm³ / h); Accompanying injection: The main gas path is started 3 seconds before liquid nitrogen injection, with a compensation amount ΔQ_O2=0.78×200+2.3×20=187.6Nm³ / h; Closed-loop compensation: Detect residual error -0.5%, switch to low-flow PID parameters (P=0.2, Ti=90s), adjust the opening of the third branch needle valve to 45%; Safety monitoring: The oxygen concentration is stable at 4995 ppm and the pressure is 1.05 MPa, indicating that the system is in a safe state.

[0050] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0051] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices or units, or may be electrical, mechanical or other forms of connection.

[0052] The units described as separate components may or may not be physically separate. As will be appreciated by those skilled in the art, the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0053] Furthermore, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0054] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, a server, or a grid device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention.

[0055] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A high-precision oxygen injection system that adapts to environmental variables, characterized in that, include: The gas source processing unit includes a dew point detector, a dual gas source switching mechanism, and a pressure pretreatment module; A staged injection unit is connected to the output end of the gas source processing unit. The staged injection unit has a high-flow main gas path and a low-flow precision regulating gas path arranged in parallel. The low-flow precision regulating gas path includes at least three independent and controllable regulating branches. An environmental sensing unit integrates a pressure sensor, a temperature sensor, an oxygen analyzer, and a liquid nitrogen injection monitoring module. The environmental sensing unit is located at least at the rear end of the stable section and the rear end of the test section of the closed-loop fluid equipment. The intelligent control unit is equipped with: The feedforward control module calculates the total oxygen demand based on real-time acquired equipment total pressure, total temperature parameters, and liquid nitrogen injection data, using the gas state equation combined with the modified equation or simulation model value. The feedforward control module executes: Calculate the total number of moles of gas n in the equipment based on PV=nRT; The required number of oxygen molecules Δn is calculated based on the target oxygen content (ppm) value obtained by the environmental sensing unit: Δn = (n × target ppm) / (10^6 - target ppm). Generate feedforward injection commands to control the injection volume = K × Δn, where K is an adjustable coefficient of 0.8-0.95; The closed-loop compensation module is activated after injection is complete. The closed-loop compensation module acquires the monitoring data of the environmental sensing unit, uses an overdamped PID algorithm to compensate for the feedforward control residual, and controls the small flow precision regulating air path to perform precise compensation. Accompanying the injection module, the high-flow main gas path is controlled in response to the liquid nitrogen injection signal, and counter-current control is performed; The accompanying injection module includes: The liquid nitrogen flow prediction submodule acquires the liquid nitrogen valve position signal in real time via the Modbus protocol. The dynamic compensation algorithm submodule establishes the transfer function between the liquid nitrogen injection amount Q_N2(t) and the oxygen compensation amount ΔQ_O2(t): ΔQ_O2(t) = α∫Q_N2(t)dt + βdQ_N2(t) / dt, Among them, α=0.78±0.05, β=2.3±0.2; The actuator initiates pre-compensation injection 2-5 seconds before liquid nitrogen injection; The safety interlock unit includes an emergency quick-cut valve assembly and an overpressure relief device.

2. The high-precision oxygen injection system for adaptive environmental variables according to claim 1, characterized in that, The feedforward control module and the closed-loop compensation module have the following features: A dual-mode regulation mechanism is used, employing a parameter set with a proportional coefficient P∈[0.5,1.5] and an integral time Ti≥30s during the high-flow phase; During low-flow phases, switch to the parameter set P∈[0.1,0.3], Ti∈[60,120s]; The differential action is limited to D≤0.05Ti.

3. The high-precision oxygen injection system for adaptive environmental variables according to claim 1, characterized in that, The staged injection unit includes: The high-flow main gas path is equipped with a DN80 pipeline and a combination of valves consisting of a first pneumatic regulating valve, a first vortex flow meter, and a first pneumatic valve, with a flow range of 800-1400 Nm³ / h; The small-flow precision regulating gas circuit has three parallel branches, each configured as follows: First branch: DN32 pipeline equipped with a second pneumatic regulating valve, a 0.1% accuracy mass flow meter and a second pneumatic valve, with a flow range of 10-50 Nm³ / h; Second branch: DN20 pipeline equipped with piezoelectric regulating valve and first flow control valve with accuracy ±1% FS, flow range 5-20Nm³ / h; The third branch: a DN10 pipeline equipped with a stepper motor driven needle valve and a second flow control valve with an accuracy of ±0.5% FS, with a flow range of 0.1-5 Nm³ / h.

4. The high-precision oxygen injection system for adaptive environmental variables according to claim 1, characterized in that, The safety interlock unit includes: Three-stage pressure protection mechanism: the first stage triggers an alarm at 1.2MPa, the second stage activates the quick-cut valve at 1.3MPa, and the third stage opens the safety valve at 1.5MPa; Oxygen concentration dual threshold protection: When the oxygen content ppm in the equipment exceeds the set value by 20%, a first-level alarm is triggered; when it exceeds 50%, an emergency purging is performed.

5. The high-precision oxygen injection system for adaptive environmental variables according to claim 1, characterized in that, The intelligent control unit is also equipped with: The equipment volume self-learning module uses data from multiple injection tests to deduce the actual volume value V'=V+ΔV; The dynamic equation correction module extends the ideal gas equation to: (P+a(n / V)^2)(V-nb) = nRT, where a and b are van der Waals correction coefficients.

6. The high-precision oxygen injection system for adaptive environmental variables according to claim 1, characterized in that, The environmental sensing unit also includes: A redundant temperature detection array, with at least 5 sets of PT100 sensors arranged along the axis from the stable section to the test section of the closed-loop fluid equipment; The pressure fluctuation compensation module uses a sliding time window algorithm to calculate the dynamic average pressure value. The pressure data processing uses the sliding time window algorithm to take the weighted average of the data from the most recent 30 seconds. P_avg=Σ(w_i×P_i) / Σw_i, where w_i=1-0.03×(30-t_i).

7. A method for using a high-precision oxygen injection system that adapts to environmental variables, characterized in that, Includes the following steps: The environmental sensing unit collects data from pressure sensors, temperature sensors, and liquid nitrogen injection monitoring modules within the closed-loop fluid equipment and calculates the total oxygen molecule demand. The feedforward control module calculates the current total number of gas moles using PV=nRT based on real-time total pressure, total temperature and liquid nitrogen data, calculates the total oxygen molecule demand in combination with the target ppm value, generates feedforward injection commands with a coefficient of 0.8-0.95, and transmits them to the accompanying injection module to control the high-flow main gas circuit valves to execute the accompanying injection. The accompanying injection module responds to the liquid nitrogen injection signal to control the high-flow main gas path and perform counter-current control; the accompanying injection module includes: The liquid nitrogen flow prediction submodule acquires the liquid nitrogen valve position signal in real time via the Modbus protocol. The dynamic compensation algorithm submodule establishes the transfer function between the liquid nitrogen injection amount Q_N2(t) and the oxygen compensation amount ΔQ_O2(t): ΔQ_O2(t) = α∫Q_N2(t)dt + βdQ_N2(t) / dt, Among them, α=0.78±0.05, β=2.3±0.2; The actuator initiates pre-compensation injection 2-5 seconds before liquid nitrogen injection; Perform closed-loop compensation: Use an overdamped PID algorithm to compensate for the feedforward residual. Use the parameter set P∈[0.5,1.5] and Ti≥30s during the high flow rate stage, and switch to the parameter set P∈[0.1,0.3] and Ti∈[60,120s] during the low flow rate stage. When the required flow rate is 30-50 Nm³ / h, the first branch mass flow meter and the second branch combined valve are used for regulation. When the required flow rate is 10-30 Nm³ / h, the combined valves of the first and third branches are used for regulation. When the required flow rate is 5-10 Nm³ / h, the combined valves of the second and third branches are used for regulation. When the required flow rate is <5Nm³ / h, the third branch stepper motor needle valve and the high-precision second flow control valve are activated for fine-tuning. Traffic overlap control is performed during branch switching to ensure that the total traffic fluctuation is less than ±0.5%.

8. The method of using the high-precision oxygen injection system with adaptive environmental variables according to claim 7, characterized in that, The feedforward control steps specifically include: Obtain the current pressure P and temperature T, and calculate the corrected volume according to V'=V+ΔV, where ΔV is obtained by back-calculation through multiple injection tests; The total number of moles of the actual gas, n, is calculated using the modified gas equation (P + a(n / V)^2)(V - nb) = nRT. Calculate the required number of oxygen molecules Δn = (n × target ppm) / (10^6 - target ppm); The generated feedforward injection rate = K × Δn, where K = 0.8 - 0.95; After the feedforward injection is completed, the closed-loop compensation is initiated. In the accompanying injection step, the dynamic compensation coefficients α and β are corrected in real time according to the ambient temperature: when 220K < T < 334K, α = 0.78 × (1 + 0.002(T - 273)); when 105K < T ≤ 220K, β = 2.3 × (1 - 0.0015(T - 273)).

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