Oxygenation device and oxygenation method for aquaculture
By constructing a dynamic evolution model of dissolved oxygen and intermittent frequency conversion control, the problem of lag in aquaculture oxygenation equipment was solved, enabling predictive and energy-saving oxygenation and ensuring the safe and efficient operation of aquaculture water bodies.
Patent Information
- Application Number
- CN202511943663.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-22
- Publication Date
- 2026-03-03
Smart Images
Figure CN121587248A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of aquaculture equipment and intelligent control, specifically to an oxygenation device and oxygenation method for aquaculture. Background Technology
[0002] Aeration in aquaculture is a crucial step in ensuring the success of high-density aquaculture. It is a technology that artificially replenishes dissolved oxygen in aquaculture water. Aquaculture aeration involves using the mechanical power generated by aeration equipment in aquaculture ponds or water bodies to agitate the water or force air into the water, increasing the surface area of water and air contact, thereby raising the dissolved oxygen content in the water. The principle is based on using an electric motor to drive an impeller or an air pump to break water surface tension, promote the exchange of water between upper and lower layers, transport oxygen-rich surface water to the bottom, and simultaneously expel harmful gases from the bottom, ensuring a sufficient respiratory environment for aquatic organisms.
[0003] To ensure the survival rate and growth rate of farmed organisms, aerators and water quality monitoring equipment are typically installed in the aquaculture area. Monitoring data is used to determine when to turn the aerators on and off. The goal of this control is usually to maintain a stable dissolved oxygen level. However, under the complex influence of the external environment, dissolved oxygen levels can easily fluctuate non-linearly, leading to localized hypoxia or a surge in energy consumption due to excessive aeration. Current technologies primarily rely on acquiring single real-time dissolved oxygen data and setting thresholds based on this data for passive on / off control. However, in practice, single real-time dissolved oxygen data has a significant lag compared to changes in the physiological needs of organisms and cannot reflect trends in the rate of oxygen consumption in the water. Relying solely on current real-time monitoring data for feedback control can result in delayed aeration intervention, inability to cope with sudden hypoxia, or continuous operation when aeration is not needed, leading to significant safety hazards in aquaculture and wasted energy.
[0004] The information disclosed in the background section is only intended to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention
[0005] The purpose of this invention is to provide an aeration device and aeration method for aquaculture to solve the problems mentioned in the background art. Specifically, the technical solution of this invention is as follows: An oxygenation method for aquaculture, comprising: S1. A floating platform, an oxygenation drive assembly, an environmental sensing unit, and a control terminal are set up. The oxygenation drive assembly includes a variable frequency motor and an inverted umbrella-shaped impeller. The variable frequency motor is vertically mounted on the central mounting base of the floating platform. The inverted umbrella-shaped impeller is coaxially fixed to the end of the output shaft of the variable frequency motor and its upper edge is close to the static water surface. The environmental sensing unit is distributed along a rigid extension rod and the rigid extension rod is fixed below the floating platform. S2. The environmental sensing unit is activated to collect data. The control terminal derives the theoretical oxygen production rate based on the light intensity and the theoretical oxygen consumption rate based on the water temperature gradient. The net dissolved oxygen flux is then corrected by combining the change in carbon dioxide calculated from the pH value change rate. S3. Construct a dynamic evolution model of dissolved oxygen, and based on the net dissolved oxygen flux and historical rhythm characteristics, deduce the trend curve of dissolved oxygen change within a set time window in the future, and lock in the predicted trough moment when the value is lower than the safety threshold. S4. Execute intermittent variable frequency pre-compensation control, start the variable frequency motor before reaching the predicted low point, and alternately execute high-speed strong disturbance oxygenation and dynamic silent diffusion when the variable frequency motor stops according to a preset strategy.
[0006] Preferably, the calculation of net dissolved oxygen flux in step S2 includes: Calculate the saturated dissolved oxygen concentration at the current temperature using the gas solubility law; Based on the principle of carbonic acid balance in water, the pH change rate is mapped to the change in carbon dioxide concentration. Based on the stoichiometric ratio of photosynthesis and respiration, the change in carbon dioxide concentration is converted back into oxygen mass flow to correct the deviation between the theoretical oxygen production rate and the theoretical oxygen consumption rate.
[0007] Preferably, step S3 includes: The measured value of the reference dissolved oxygen probe was used as a benchmark; The water body is divided into several thermal stratification regions using vertical temperature gradient data obtained by temperature array probes. Based on the principle of thermal stratification barrier to material exchange and the diffusion damping coefficient between each layer, the estimated value of dissolved oxygen at different depths is derived layer by layer to generate a virtual global distribution of dissolved oxygen in the water body.
[0008] Preferably, step S4 includes: S4.1 Statistical analysis of the variance of pH value fluctuation and the number of times the pH value crosses the mean per unit time; S4.2 When the variance of the numerical fluctuation is less than a preset micro-amplitude threshold and the number of times the mean value is crossed is greater than a preset high-frequency threshold, the water body is determined to be in a high metabolic accumulation state. S4.3. Based on Fick's diffusion law, derive the physical diffusion transport rate and compare it with the real-time biological metabolic intensity to calculate the maximum allowable silence duration.
[0009] Preferably, step S4.3 is followed by: S4.4 Determine the relationship between the original silent time and the maximum allowable silent time; S4.5 If the original silent time exceeds the maximum allowable silent time, control the variable frequency motor to switch to a low-speed flow field maintenance state to replace the stop.
[0010] Preferably, step S4 is followed by: Monitor the slope of dissolved oxygen changes after oxygenation; If the actual acceleration slope is higher than the theoretical slope of the prediction model, the control terminal will automatically reduce the target speed of the variable frequency motor in the next cycle.
[0011] An aeration device for aquaculture, comprising: The floating platform includes an annular pontoon and a central mounting base supported at the center of the annular pontoon by a rigid connecting beam. An oxygenation drive assembly is mounted on the central mounting base and includes a variable frequency motor and an inverted umbrella-shaped impeller. The inverted umbrella-shaped impeller is coaxially fixed to the end of the output shaft of the variable frequency motor and its upper edge is close to the static water surface. An environmental sensing unit is mounted on a rigid extension rod, which is parallel to the output shaft of the variable frequency motor and maintains a preset radial distance. The environmental sensing unit includes a light intensity sensor mounted on the top of the rigid extension rod and protruding above the water surface, a temperature array probe fixedly distributed along the axial direction of the rigid extension rod, a pH monitor mounted on the bottom of the rigid extension rod, and a reference dissolved oxygen probe located in the middle of the rigid extension rod. The control terminal is located on the floating platform and is electrically connected to the oxygenation drive component and the environmental sensing unit.
[0012] Preferably, the inverted umbrella-shaped impeller includes a conical structure, which forms a negative pressure zone at the center when rotating, drawing in the lower water body axially upward and dispersing it radially outward.
[0013] Compared with the prior art, the present invention has the following improvements and advantages: 1. This scheme derives the theoretical oxygen production rate using light intensity and the theoretical oxygen consumption rate using water temperature gradient, and corrects for the net dissolved oxygen flux by incorporating the carbon dioxide change calculated from the pH change rate. Unlike existing technologies that rely solely on the passive mode of dissolved oxygen numerical triggering, this scheme constructs a dynamic evolution model of dissolved oxygen, projecting its changing trend over a set time window. This allows the system to intervene before the predicted trough, effectively avoiding the risk of oxygen depletion due to passive response through intermittent variable frequency pre-compensation control, and significantly improving the timeliness of oxygenation. 2. This scheme introduces the pH change rate as a correction term and utilizes the principle of carbon dioxide balance in water and the stoichiometric ratio of photosynthesis and respiration to inversely convert the change in carbon dioxide concentration into oxygen mass flow. Unlike existing technologies that directly use theoretical models or single-point measurements, this scheme compensates for theoretical deviations caused by fluctuations in actual aquaculture density and plankton biomass, resulting in a calculated net dissolved oxygen flux that more closely reflects the actual biochemical metabolic state of the water body, thus improving the scientific rigor of the control strategy. 3. This solution utilizes a temperature array probe to acquire vertical temperature gradient data. Based on the principle of thermal stratification barrier for mass exchange and diffusion damping coefficient, it extrapolates the dissolved oxygen estimates at different depths layer by layer. Unlike existing technologies that can only acquire local data at the probe's location, this solution generates a virtual global distribution of dissolved oxygen in the water, supplementing the blind spots of hardware sensing. This effectively prevents oxygen-deficient cavities at the bottom or in localized areas caused by thermal stratification barrier, ensuring the safety of the entire aquaculture water column space. 4. This scheme derives the physical diffusion transport rate based on Fick's diffusion law and compares it with real-time biological metabolic intensity to calculate the maximum allowable quiet period. Unlike existing technologies that rely on crude timed or frequency-based operation, this scheme fully utilizes natural physical diffusion oxygenation capabilities while ensuring dissolved oxygen levels do not fall below the safe threshold, achieving maximum energy savings during shutdown. Simultaneously, a degraded operation strategy is implemented, automatically switching to a low-speed flow field maintenance state when the originally planned quiet period exceeds the maximum allowable quiet period, achieving an optimal balance between energy saving and maintaining water convection. 5. This solution places the environmental sensing unit below the floating platform via a rigid extension rod, maintaining a preset radial distance from areas of strong disturbance. Unlike existing sensors that are susceptible to interference from aeration turbulence, this physical isolation ensures that the collected data represents the natural state of the water body. Simultaneously, the conical structure of the inverted umbrella-shaped impeller creates a central negative pressure zone during rotation, capable of drawing in and dispersing deep, oxygen-deficient water. Compared to traditional impellers, this significantly increases the gas-liquid contact area and improves liquid-phase mass transfer efficiency. Attached Figure Description
[0014] The present invention will be further explained below with reference to the accompanying drawings and embodiments: Figure 1This is a top view of the device's structure. Figure 2 This is a schematic diagram of the device from below. Figure 3 This is a schematic diagram of the process flow of the method of the present invention.
[0015] In the diagram: 100, floating platform; 110, annular float; 120, central mounting base; 200, oxygenation drive assembly; 210, variable frequency motor; 220, inverted umbrella-shaped impeller; 300, environmental sensing unit; 310, rigid extension rod; 320, illuminance sensor; 330, temperature array probe; 340, pH monitor; 350, reference dissolved oxygen probe; 400, control terminal. Detailed Implementation
[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. Example 1
[0017] Please see Figure 1-3 This invention provides an oxygenation method for aquaculture, comprising: S1. A floating platform 100, an oxygenation drive assembly 200, an environmental sensing unit 300, and a control terminal 400 are set up. The oxygenation drive assembly 200 includes a variable frequency motor 210 and an inverted umbrella-shaped impeller 220. The variable frequency motor 210 is vertically mounted on the central mounting base 120 of the floating platform 100. The inverted umbrella-shaped impeller 220 is coaxially fixed to the end of the output shaft of the variable frequency motor 210 and its upper edge is close to the static water surface. The environmental sensing unit 300 is distributed along the rigid extension rod 310 and the rigid extension rod 310 is fixed below the floating platform 100. S2. Start the environmental sensing unit 300 to collect data. The control terminal 400 derives the theoretical oxygen production rate based on the light intensity and the theoretical oxygen consumption rate based on the water temperature gradient. It then corrects the net dissolved oxygen flux by combining the change in carbon dioxide calculated from the pH value change rate. S3. Construct a dynamic evolution model of dissolved oxygen, and based on the net dissolved oxygen flux and historical rhythm characteristics, deduce the trend curve of dissolved oxygen change within a set time window in the future, and lock in the predicted trough moment when the value is lower than the safety threshold. S4. Execute intermittent variable frequency pre-compensation control, start the variable frequency motor 210 before reaching the predicted low point, and alternately execute high-speed strong disturbance oxygenation and dynamic silent diffusion when the variable frequency motor 210 stops, according to the preset strategy.
[0018] In this embodiment, the oxygenation method for aquaculture is mainly used to solve the problem that existing aquaculture oxygenation equipment relies on a single dissolved oxygen data for passive response, resulting in a lag in oxygenation. In step S1, the aeration method for aquaculture establishes a basic framework through a specific spatial arrangement of physical components. A floating platform 100 is set up as a water surface carrier, and the aeration drive assembly 200, consisting of a variable frequency motor 210 and an inverted umbrella-shaped impeller 220, is placed at the center to ensure that the mechanical disturbance source is at the core of the operation. The environmental sensing unit 300 is supported below the water body by a rigid extension rod 310. Through this physical isolation, the data collected by the sensor can represent the natural water state of the non-strongly disturbed area. In step S2, the aeration method for aquaculture uses a control terminal 400 to perform multi-source data fusion, converting environmental factors such as light and temperature into quantitative indicators of biochemical processes, thereby calculating the net dissolved oxygen flux, which is not directly measured. This flux reflects the dynamic difference between oxygen production and oxygen consumption in the water body at the current moment. In step S3, the aeration method for aquaculture, based on the current net dissolved oxygen flux, retrieves data characteristics from historically stored similar meteorological conditions and extrapolates them forward on the time axis, thereby generating a dissolved oxygen change trend curve before the actual occurrence of hypoxia. In step S4, the oxygenation method used for aquaculture intervenes in advance before the predicted low point, based on the prediction results. It controls the operation of the variable frequency motor 210 to rapidly increase the oxygen content through strong disturbance oxygenation. Combined with dynamic silent diffusion, it utilizes the concentration difference for natural transport, thereby ensuring the oxygen demand of organisms while reducing the energy consumption of equipment operation.
[0019] The calculation of net dissolved oxygen flux in step S2 includes: Calculate the saturated dissolved oxygen concentration at the current temperature using the gas solubility law; Based on the principle of carbonic acid balance in water, the rate of change of pH value is mapped to the change in carbon dioxide concentration. The specific mapping logic follows these steps: Step 1: The control terminal 400 extracts the time series data from the pH monitor 340, and obtains the real-time pH change rate through differential processing. Step 2: Based on the preset total alkalinity constant and carbonic acid dissociation equilibrium constant of the water body, the charge balance equation is used to... This is converted to the rate of change of total inorganic carbon; the specific charge balance equation is: ; in The total alkalinity constant is either preset or measured. Represents the molar concentration of each ion; Step 3: Assuming that the alkalinity remains constant over a short period of time, attribute all changes in total inorganic carbon to dissolved carbon dioxide. The increase or decrease of carbon dioxide concentration is converted into oxygen mass flow based on the stoichiometric ratio of photosynthesis and respiration, thereby correcting the deviation between the theoretical oxygen production rate and the theoretical oxygen consumption rate.
[0020] In this embodiment, the calculation of net dissolved oxygen flux in step S2 focuses on establishing the biochemical correlation between indirect measurement parameters and dissolved oxygen. The saturated dissolved oxygen concentration at the current temperature is calculated using the gas solubility law, determining the upper limit of oxygen that the current water body can physically hold, providing a physical boundary for subsequent calculations. Based on the principle of carbonic acid balance in the water body, the control terminal 400 maps the rate of change of pH value to the change in carbon dioxide concentration. This process utilizes the chemical correlation between the release of carbon dioxide by biological respiration causing a decrease in pH and the consumption of carbon dioxide by photosynthesis causing an increase in pH. Based on the stoichiometric ratio of photosynthesis and respiration, step S2 reverses the derived change in carbon dioxide concentration to an oxygen mass flow. Since the theoretical oxygen production rate is derived based on light and the theoretical oxygen consumption rate is derived based on temperature, both are ideal model values. By introducing the oxygen mass flow converted from pH value as a correction term, errors caused by fluctuations in actual aquaculture density and plankton biomass can be compensated, thus making the calculated net dissolved oxygen flux closer to the actual biochemical metabolic state of the water body. The net dissolved oxygen flux calculation logic executed by the control terminal 400 follows these steps: The theoretical oxygen production rate is derived. The system uses light intensity data collected by a 320 illuminance sensor and employs photosynthetic light response logic for calculation. This means that the oxygen production rate is positively correlated with light intensity within a certain range. Once the light intensity exceeds the light saturation point, the oxygen production rate remains constant. The specific calculation uses the Stiell formula: ;
[0021] in, For the maximum photosynthetic rate, To measure the actual light intensity, To achieve the optimal light intensity; and This is an empirical constant obtained by fitting historical monitoring data of aquaculture waters through nonlinear regression.
[0022] The theoretical oxygen consumption rate is derived. The system is based on water temperature data and utilizes van der Hoff's rule or... The temperature coefficient logic is used to deduce that for every specific temperature gradient increase, such as 10°C, the biological oxygen consumption rate will increase exponentially. The specific calculation formula is as follows: ;
[0023] in, The standard oxygen consumption rate at 20℃ The current water temperature, temperature coefficient The value is 2.0. The oxygen consumption rate of aquaculture water samples was obtained by laboratory measurement under constant temperature conditions of 20℃.
[0024] Perform a pH-based correction calculation. This calculation logic is based on the following mass balance relationship: ;
[0025] in: This represents the final output net dissolved oxygen flux; a positive value indicates an oxygen surplus, and a negative value indicates an oxygen deficit. This represents the theoretical oxygen production rate derived above; This represents the theoretical oxygen consumption rate derived above; This represents the pH correction term. The calculation logic is as follows: Monitor the slope of pH changes. If the pH shows a downward trend, it indicates an increase in carbon dioxide concentration in the water. Based on the stoichiometry, this corresponds to an increase in respiration intensity. The system will then generate a negative correction value to reflect the additional oxygen consumption exceeding the theoretical model. The specific calculation formula is as follows: ;
[0026] in, For the rate of pH change, This is the water body buffer capacity coefficient, which is determined by the control terminal based on the current measured pH value and the preset total alkalinity constant. By consulting pre-stored water chemical buffer strength curves or by using equations Calculated in real time; This is the photosynthetic respiration quotient conversion factor, whose value includes a stoichiometric factor to convert the molar mass of carbon to the mass of oxygen, ensuring that the units of the final calculation result are consistent with... Unified as Conversely, if the pH value increases, a positive correction value is generated.
[0027] The steps in S3 include: The measured value of the reference dissolved oxygen probe 350 was used as the benchmark; The water body is divided into several thermal stratification regions using vertical temperature gradient data obtained by temperature array probe 330. Based on the principle of thermal stratification barrier to material exchange and the diffusion damping coefficient between each layer, the estimated value of dissolved oxygen at different depths is derived layer by layer to generate a virtual global distribution of dissolved oxygen in the water body.
[0028] In this embodiment, the process of constructing the dissolved oxygen dynamic evolution model in step S3 utilizes the logic of extrapolating global field data from single-point measured data. The measured value of the reference dissolved oxygen probe 350 is used as a benchmark, providing a definite anchor point for the model. Vertical temperature gradient data acquired by the temperature array probe 330 is used to divide the water body into several thermal stratification regions. Due to the different densities of water at different temperatures, thermal stratification forms a barrier that hinders vertical material exchange. Based on the principle of thermal stratification blocking material exchange and the diffusion damping coefficient between layers, step S3 simulates the physical difficulty of oxygen molecules penetrating between water layers of different densities. Starting from the measured layer, the oxygen transfer amount of adjacent water layers is calculated layer by layer, thereby extrapolating the dissolved oxygen estimate at depths where no dissolved oxygen probe is deployed. This method supplements the blind spots of hardware sensing through calculation, generating a virtual global distribution of dissolved oxygen in the water body, enabling the determination of predicted trough times to cover the entire aquaculture water column space rather than being limited to the probe location.
[0029] Logically, the model treats the water column as several series-connected control volumes, with the oxygen transfer resistance between each control volume determined by the temperature gradient at their interface. When a thermocline exists between two layers, the model automatically increases the diffusion damping coefficient at that interface, specifically based on the Richardson number. To quantify the stability of the hierarchical structure, where The calculation formula is: ;
[0030] In the formula, The buoyancy frequency, calculated based on the vertical temperature gradient obtained from the temperature array probe, is given by the following formula: ;
[0031] in It is the acceleration due to gravity. For reference density, The density gradient is derived using the temperature gradient; The average velocity shear rate constant is preset based on the hydrodynamic characteristics of the aquaculture area; the formula is used. Calculate the current diffusion damping coefficient ,in The diffusion coefficient under neutral stratification. , This is an empirical constant, and its typical value range is [value range missing]. , The specific values are determined by fitting the measured turbulence characteristics of the aquaculture water area. In terms of calculation logic, it significantly reduces the transfer flux of the upper oxygen-rich water to the lower layer, thus showing the hypoxia trend of the bottom layer in the virtual distribution state. The dissolved oxygen dynamic evolution model is constructed using an iterative algorithm with discrete time steps, and its state equation is: ;
[0032] in, This represents the current dissolved oxygen concentration. For net biochemical flux, This refers to the interlayer physical diffusion transport rate. per unit water layer volume Using this equation as the time step, the system, after unifying the time dimensions of each parameter, corrects it using historical rhythm characteristics. The future parameters are used to iteratively extrapolate the future time window. curve.
[0033] The steps in S4 include: S4.1 Statistical analysis of the variance of pH value fluctuation and the number of times the pH value monitor 340 crosses the mean within a unit of time; S4.2 When the variance of the numerical fluctuation is less than the preset micro-threshold and the number of times the mean is crossed is greater than the preset high-frequency threshold, the water body is determined to be in a state of high metabolic accumulation. S4.3. Based on Fick's diffusion law, derive the physical diffusion transport rate and compare it with the real-time biological metabolic intensity to calculate the maximum allowable silence duration.
[0034] In this embodiment, step S4 dynamically adjusts the control strategy by analyzing the microscopic fluctuation characteristics of the water body. Steps S4.1 and S4.2 focus on the data characteristics of the pH monitor 340. When the biological density in the water body is extremely high and metabolism is vigorous, the rapid respiration will cause the pH of the microenvironment to exhibit high-frequency micro-amplitude oscillations. By statistically analyzing the variance of the numerical fluctuations and the number of times the mean is crossed, the system can identify this high metabolic aggregation state and distinguish it from simple gradual changes in water quality. Step S4.3 derives the physical diffusion transport rate based on Fick's diffusion law and calculates the rate of change in the absence of organic matter. When mechanically agitated, oxygen diffuses naturally due to the concentration difference. This physical diffusion rate is compared with the real-time biological metabolic intensity, which reflects the rate of biological oxygen consumption. If biological oxygen consumption is faster than physical diffusion, the quiescent time must be shortened. Regarding the threshold setting logic in S4.2: the preset micro-threshold is not a fixed constant, but is calibrated based on the base noise of the sensor operating in pure water. It is usually set to 3-5 times the base noise, aiming to filter electrical noise while retaining small disturbance signals of biological activity. The preset high-frequency threshold is set based on the respiratory frequency characteristics of the cultured object, such as fish.
[0035] The preset micro-threshold is a signal purity indicator used to define whether pH fluctuations are due to a simple shift in the chemical balance of the water body, usually manifested as a smooth curve, or as a superposition of respiratory pulses from biological communities, manifested as sawtooth-like micro-shaking. The preset high-frequency threshold is a biological activity indicator, and its value is set based on the respiratory frequency characteristics of the cultured organisms. For example, the respiratory frequency of fish is usually in the range of 0.5-2Hz. When the frequency that crosses the mean falls into this range, it is logically determined that the current pH change is directly driven by the respiratory metabolism of the high-density biological community, rather than caused by external acid rain or bottom sediment release. Regarding the calculation logic for the maximum permissible silence duration in S4.3: This calculation is based on the critical point of supply and demand balance. The system derives the physical diffusion transmission rate based on Fick's first law. The calculation logic is as follows: ;
[0036] in: It represents the physical diffusion transport rate, which is the amount of oxygen that enters the lower water body through natural diffusion per unit time; This represents the horizontal cross-sectional area of a unit control volume; This represents the turbulent diffusion coefficient, which is inversely proportional to the Richardson number, representing the temperature stratification stability of the current water body. This indicates the saturated dissolved oxygen concentration in surface water. This indicates the depth concentration measured with reference to the 350 dissolved oxygen probe. This indicates the vertical height difference between the two.
[0037] The system calculates the maximum allowed silent duration. The calculation logic is as follows: divide the current residual oxygen content in the water body that is above the safety threshold by the difference between the real-time biological metabolic intensity and the physical diffusion transport rate. This logic ensures that... At the end, the dissolved oxygen concentration in the water just returned to above the safe threshold, thus theoretically exhausting the potential of natural diffusion. If the real-time biological metabolic intensity is less than the physical diffusion rate, resulting in a negative or infinite calculation result, it is determined that natural diffusion is sufficient to maintain oxygen balance, and the control terminal will... Set to the preset maximum standby period.
[0038] The maximum permissible quiet time calculated through this comparison ensures that while performing intermittent shutdowns to save energy, there is no risk of localized hypoxia in high-density biological communities due to excessively long shutdown times.
[0039] The steps following S4.3 include: S4.4 Determine the relationship between the original silence time and the maximum allowable silence duration; S4.5 If the original silent time exceeds the maximum allowable silent time, control the variable frequency motor 210 to switch to low speed flow field maintenance state to replace the stop.
[0040] In this embodiment, step S4.5 provides a degraded operation strategy for high-risk scenarios. In the conventional strategy, dynamic silent diffusion with the motor completely stopped is executed to save energy. When S4.4 determines that the original silent time exceeds the maximum allowable silent time, it means that natural diffusion alone cannot meet the oxygen demand of organisms. At this time, the variable frequency motor 210 is switched to a low-speed flow field maintenance state. In this low-speed state, although the inverted umbrella impeller 220 does not produce a strong oxygenation hydraulic jump, it can still maintain the slow convection of the water body. This is because the low-speed operation of the motor only needs to provide the minimum torque to overcome the viscous resistance of the water body, which aims to break the static laminar flow state of the water body and promote the homogenization of solutes in the vertical and horizontal directions, without having to provide the high energy required to break the surface tension of the water for aeration as in the strong disturbance mode. Thus, the boundary layer of the bottom static anoxic zone is destroyed with extremely low energy consumption. This mechanically assisted convection can make up for the insufficiency of natural diffusion and prevent the formation of local anoxic cavities, thereby achieving a balance between energy saving and safety.
[0041] The steps following S4 include: Monitor the slope of dissolved oxygen changes after oxygenation; If the actual slope of the increase is higher than the theoretical slope of the prediction model, the control terminal 400 will automatically reduce the target speed of the variable frequency motor 210 in the next cycle.
[0042] In this embodiment, the monitoring step following step S4 establishes a feedback mechanism for energy efficiency optimization. Monitoring the slope of dissolved oxygen changes after aeration reflects the actual response speed of the water body to the aeration operation. If the actual slope is higher than the theoretical slope of the prediction model, it indicates that the current oxygen-holding capacity of the water body is strong or biological oxygen consumption is lower than expected. The originally planned high-speed operation results in energy overflow. Based on this, the control terminal 400 automatically reduces the target speed of the variable frequency motor 210 for the next cycle. Through this adaptive adjustment, energy waste caused by excessive aeration is avoided, ensuring that the aeration intensity always matches the actual needs of the water body. Monitoring the slope of dissolved oxygen changes after aeration is essentially a measure of the total oxygen mass transfer coefficient. Dynamic evaluation.
[0043] The calculation logic is as follows: During the strong disturbance phase of mechanical aeration startup, the rate of increase in dissolved oxygen concentration mainly depends on two factors: the oxygenation capacity of the aerator and the current oxygen deficit in the water.
[0044] The system defines the actual slope increase as the increment of the measured dissolved oxygen value per unit time.
[0045] The system defines the theoretical slope of the prediction model as the tangent slope of the ideal oxygenation curve derived under standard operating conditions based on the current water temperature, air pressure, and theoretical motor power.
[0046] If the actual slope is higher than the theoretical slope, logically it means that there are fewer surface-active substances in the water, the gas-liquid interface resistance is low, or the actual oxygen consumption is lower than the estimated value in step S2. At this time, the system determines that maintaining the current high speed will cause dissolved oxygen to quickly reach saturation and overflow. Therefore, it executes the deceleration logic, reducing the frequency of the variable frequency motor 210 to reduce the input power, so that the actual slope gradually approaches the theoretical slope, achieving optimal energy efficiency. Example 2
[0047] Please see Figures 1 to 2 An aeration device for aquaculture, comprising: The floating platform 100 includes an annular pontoon 110 and a central mounting base 120 supported at the center of the annular pontoon 110 by a rigid connecting beam. An oxygenation drive assembly 200 is mounted on a central mounting base 120 and includes a variable frequency motor 210 and an inverted umbrella-shaped impeller 220. The inverted umbrella-shaped impeller 220 is coaxially fixed to the end of the output shaft of the variable frequency motor 210 and its upper edge is close to the static water surface. An environmental sensing unit 300 is mounted on a rigid extension rod 310. The rigid extension rod 310 is parallel to the output shaft of the variable frequency motor 210 and maintains a preset radial distance. The environmental sensing unit 300 includes a light intensity sensor 320 mounted on the top of the rigid extension rod 310 and protruding above the water surface, a temperature array probe 330 distributed and fixed along the axial direction of the rigid extension rod 310, a pH monitor 340 mounted on the bottom of the rigid extension rod 310, and a reference dissolved oxygen probe 350 located in the middle of the rigid extension rod 310. The control terminal 400 is installed on the floating platform 100 and is electrically connected to the oxygenation drive component 200 and the environmental sensing unit 300.
[0048] In this embodiment, the device provides a physical carrier for performing the aforementioned oxygenation method. The floating platform 100 utilizes an annular float 110 to provide stable buoyancy, and a rigid connecting beam concentrates the stress point at the center, providing a stable support foundation for the central mounting base 120. The oxygenation drive assembly 200 is powered by a variable frequency motor 210 mounted on the central mounting base 120. The variable frequency motor 210 is typically an industrial-grade AC variable frequency speed control motor, whose output shaft drives an inverted umbrella-shaped impeller 220 located below the water surface to rotate, thereby implementing mechanical oxygenation. The environmental sensing unit 300, physically supported by a rigid extension rod 310, is positioned in a statically stable region maintaining a preset radial distance from the stirring area, avoiding direct interference from bubbles and turbulence on the sensor data. The control terminal 400, serving as the computing and command center, integrates a microprocessor and variable frequency drive circuitry. Through electrical connections, it aggregates data from the environmental sensing unit 300 and sends control commands to the oxygenation drive assembly 200.
[0049] The environmental sensing unit 300 includes: A light intensity sensor 320 is mounted on the top of a rigid extension rod 310 and protrudes above the water surface; Temperature array probes 330 are fixedly distributed along the axial direction of rigid extension rod 310; pH monitor 340 is installed at the bottom of rigid extension rod 310; The dissolved oxygen probe 350 is positioned in the middle of the rigid extension rod 310.
[0050] In this embodiment, the spatial layout of each component of the environmental sensing unit 300 is optimized according to the physical characteristics of its monitored objects. The illuminance sensor 320 is installed at the top, protruding above the water surface, to directly receive solar radiation and provide source data for calculating oxygen production through photosynthesis. The temperature array probes 330 are distributed along the axial direction, enabling simultaneous acquisition of temperature data at different water depths, thereby capturing the thermal stratification structure of the water body. The pH monitor 340 is located at the bottom, where there is usually more sediment and strong respiration, allowing it to sensitively capture the changing trends of pH at the bottom. The reference dissolved oxygen probe 350 is set in the middle, avoiding the high-oxygen zone at the surface and the oxygen-consuming zone at the bottom, providing a representative average dissolved oxygen level of the water column as benchmark data for model calibration.
[0051] The inverted umbrella-shaped impeller 220 includes a conical structure. When rotating, the conical structure forms a negative pressure zone at the center, which draws in the lower water body axially upward and throws it radially outward.
[0052] In this embodiment, the inverted umbrella-shaped impeller 220 utilizes fluid dynamics principles to achieve vertical water exchange. Its conical structure, when rotating at high speed, functions similarly to a centrifugal pump, creating a strong negative pressure zone in the central area. This negative pressure zone generates a suction effect, drawing deep, oxygen-deficient water upwards axially. This inverted conical design changes the traditional impeller's method of oxygenation primarily through slapping surface water, constructing an upflow channel similar to a tornado. This forces the bottom water to participate in gas-liquid exchange. Under centrifugal force, the water is radially dispersed, breaking it down into fine droplets, significantly increasing the gas-liquid contact area and achieving a highly efficient reoxygenation process. Combined with the speed regulation of the variable frequency motor 210, the scale of water lift can be precisely controlled.
[0053] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention.
Claims
1. An oxygenation method for aquaculture, characterized in that, include: S1. A floating platform (100), an oxygenation drive assembly (200), an environmental sensing unit (300), and a control terminal (400) are set up. The oxygenation drive assembly (200) includes a variable frequency motor (210) and an inverted umbrella-shaped impeller (220). The variable frequency motor (210) is vertically mounted on the central mounting seat (120) of the floating platform (100). The inverted umbrella-shaped impeller (220) is coaxially fixed to the end of the output shaft of the variable frequency motor (210) and its upper edge is close to the static water surface. The environmental sensing unit (300) is distributed along a rigid extension rod (310) and the rigid extension rod (310) is fixed below the floating platform (100). S2. Start the environmental sensing unit (300) to collect data. The control terminal (400) derives the theoretical oxygen production rate based on the light intensity, derives the theoretical oxygen consumption rate based on the water temperature gradient, and corrects the net dissolved oxygen flux by combining the change in carbon dioxide calculated by the pH value change rate. S3. Construct a dynamic evolution model of dissolved oxygen, and based on the net dissolved oxygen flux and historical rhythm characteristics, deduce the trend curve of dissolved oxygen change within a set time window in the future, and lock in the predicted trough moment when the value is lower than the safety threshold. S4. Perform intermittent variable frequency pre-compensation control, start the variable frequency motor (210) before reaching the predicted low point, and alternately perform high-speed strong disturbance oxygenation and dynamic silent diffusion when the variable frequency motor (210) stops, according to the preset strategy.
2. The oxygenation method for aquaculture according to claim 1, characterized in that, The calculation of net dissolved oxygen flux in step S2 includes: Calculate the saturated dissolved oxygen concentration at the current temperature using the gas solubility law; Based on the principle of carbonic acid balance in water, the pH change rate is mapped to the change in carbon dioxide concentration. Based on the stoichiometric ratio of photosynthesis and respiration, the change in carbon dioxide concentration is converted back into oxygen mass flow to correct the deviation between the theoretical oxygen production rate and the theoretical oxygen consumption rate.
3. The oxygenation method for aquaculture according to claim 1, characterized in that, Step S3 includes: The measured value of the reference dissolved oxygen probe (350) was used as a benchmark; The water body is divided into several thermal stratification regions using vertical temperature gradient data obtained by the temperature array probe (330); Based on the principle of thermal stratification barrier to material exchange and the diffusion damping coefficient between each layer, the estimated value of dissolved oxygen at different depths is derived layer by layer to generate a virtual global distribution of dissolved oxygen in the water body.
4. The oxygenation method for aquaculture according to claim 1, characterized in that, Step S4 includes: S4.1 Statistical analysis of the variance of pH value fluctuation and the number of times the mean is crossed by the pH value monitor (340) per unit time; S4.2 When the variance of the numerical fluctuation is less than a preset micro-amplitude threshold and the number of times the mean value is crossed is greater than a preset high-frequency threshold, the water body is determined to be in a high metabolic accumulation state. S4.
3. Based on Fick's diffusion law, derive the physical diffusion transport rate and compare it with the real-time biological metabolic intensity to calculate the maximum allowable silence duration.
5. The oxygenation method for aquaculture according to claim 4, characterized in that, The steps following S4.3 include: S4.4 Determine the relationship between the original silent time and the maximum allowable silent time; S4.5 If the original silent time exceeds the maximum allowable silent time, control the variable frequency motor (210) to switch to low speed flow field maintenance state to replace the stop.
6. The oxygenation method for aquaculture according to claim 1, characterized in that, The step S4 is followed by: Monitor the slope of dissolved oxygen changes after oxygenation; If the actual slope of the increase is higher than the theoretical slope of the prediction model, the control terminal (400) automatically reduces the target speed of the variable frequency motor (210) in the next cycle.
7. An aeration device for aquaculture, characterized in that, The control terminal (400) is configured to perform an oxygenation method for aquaculture as described in any one of claims 1 to 6, the apparatus comprising: The floating platform (100) includes an annular pontoon (110) and a central mounting base (120) supported at the center of the annular pontoon (110) by a rigid connecting beam. An oxygenation drive assembly (200) is mounted on the central mounting base (120) and includes a variable frequency motor (210) and an inverted umbrella-shaped impeller (220). The inverted umbrella-shaped impeller (220) is coaxially fixed to the end of the output shaft of the variable frequency motor (210) and its upper edge is close to the static water surface. An environmental sensing unit (300) is mounted on a rigid extension rod (310). The rigid extension rod (310) is parallel to the output shaft of the variable frequency motor (210) and maintains a preset radial distance. The environmental sensing unit (300) includes a light intensity sensor (320) mounted on the top of the rigid extension rod (310) and protruding above the water surface, a temperature array probe (330) fixedly distributed along the axial direction of the rigid extension rod (310), a pH monitor (340) mounted on the bottom of the rigid extension rod (310), and a reference dissolved oxygen probe (350) located in the middle of the rigid extension rod (310). A control terminal (400) is disposed on the floating platform (100) and electrically connected to the oxygenation drive assembly (200) and the environmental sensing unit (300).
8. An aeration device for aquaculture according to claim 7, characterized in that, The inverted umbrella-shaped impeller (220) includes a conical structure that forms a negative pressure zone at the center when rotating, drawing in the lower water body axially upward and dispersing it radially outward.