An oxygen supply method for high-density tilapia farming

Abstract

This invention discloses an oxygen supply method for high-density tilapia farming, relating to the field of aquaculture technology. The method includes the following steps: real-time monitoring of dissolved oxygen data in the farming water; determining whether oxygen supply triggering conditions are met based on the dissolved oxygen data; when the triggering conditions are met, activating a wave generator and simultaneously supersaturating liquid oxygen with a portion of the farming water in a dissolved oxygen cone mixer to generate highly oxygenated water; injecting the highly oxygenated water into the farming water, allowing the directional horizontal flow generated by the wave generator to evenly diffuse the highly oxygenated water throughout the pond; and stopping liquid oxygen supply and mixing when the dissolved oxygen data rises to a preset dissolved oxygen threshold, with the wave generator continuing to run for a preset time before stopping. This invention solves the problems of uneven dissolved oxygen distribution, high energy consumption, and low efficiency inherent in traditional high-density tilapia farming techniques.

Description

Technical Field

[0001] This invention relates to the field of aquaculture technology, and in particular to an oxygen supply method for high-density tilapia farming. Background Technology

[0002] Currently, the commonly used aeration technologies in high-density tilapia farming mainly include impeller / paddlewheel aerators, microporous aeration systems, and pure oxygen aeration systems. All of these systems follow a connection relationship from the power source to the air / transmission device to the air-water contact device to the water body.

[0003] However, existing technologies still have significant drawbacks: First, the oxygenation range is limited, which easily leads to dissolved oxygen dead zones at the bottom and corners of the pond, resulting in uneven fish growth and low feed utilization. Second, the oxygen transfer efficiency of traditional mechanical aeration is low, and a large amount of electrical energy is consumed in water agitation. Third, in the event of sudden weather changes or high biological load in the later stages of aquaculture, the oxygenation efficiency is low, making it difficult to quickly increase the dissolved oxygen in the entire pond, which can easily cause fish to surface for air or even suffocate. Summary of the Invention

[0004] The main objective of this invention is to propose an oxygen supply method for high-density tilapia farming, aiming to solve the problems of uneven dissolved oxygen distribution, high energy consumption, and low efficiency in traditional high-density tilapia farming.

[0005] To achieve the above objectives, this invention proposes an oxygen supply method for high-density tilapia farming, comprising the following steps: Real-time monitoring of dissolved oxygen data in aquaculture water; Determine whether the oxygen supply triggering conditions are met based on the dissolved oxygen data; When the oxygen supply triggering conditions are met, the wave generator is activated, and liquid oxygen is simultaneously supersaturated and mixed with a portion of the aquaculture water in the dissolved oxygen cone mixer to generate highly oxygenated water. The highly oxygenated water is injected into the aquaculture water body so that the directional horizontal flow generated by the wave generator can evenly spread the highly oxygenated water throughout the entire pond. When the dissolved oxygen data rises back to the preset dissolved oxygen threshold, the liquid oxygen supply and mixing are stopped, and the wave generator continues to run for a preset time before stopping.

[0006] In one embodiment, the step of supersaturating mixing of liquid oxygen with a portion of the aquaculture water in a dissolved oxygen cone mixer to generate highly oxygenated water includes: Based on the real-time oxygen deficit, a command is sent to the electric proportional regulating valve installed on the main liquid oxygen pipeline between the liquid oxygen tank and the dissolved oxygen cone mixer to open the corresponding valve opening, so that liquid oxygen enters the liquid oxygen inlet at the top of the dissolved oxygen cone from the liquid oxygen tank after depressurization at a set flow rate. Start the inlet pump of the dissolved oxygen cone to pump pond water from the pond into the inlet at the top of the dissolved oxygen cone; The aquaculture water entering the dissolved oxygen cone forms a strong swirling flow along the spiral guide vanes on the inner wall. At the same time, liquid oxygen is injected into the swirling water through the microporous jet ring at the top of the dissolved oxygen cone to form a gas-liquid mixture. The gas-liquid mixture continues to flow through the static mixing unit in the lower part of the dissolved oxygen cone, so that the gas-liquid mixture is instantly supersaturated and dissolved to generate highly oxygenated water. The highly oxygenated water is discharged from the outlet at the bottom of the dissolved oxygen cone to a location in the aquaculture water body near the wave generator.

[0007] In one embodiment, the step of real-time detection of dissolved oxygen data in the aquaculture water body further includes: Multiple dissolved oxygen monitoring points are set up in the aquaculture water body; the oxygen supply triggering condition is that the average dissolved oxygen value of the multiple dissolved oxygen monitoring points is lower than the preset dissolved oxygen threshold.

[0008] In one embodiment, there are 5 dissolved oxygen monitoring points, which are located at the four corners of the pond and the center of the pond, respectively. The dissolved oxygen monitoring points located at the four corners of the pond are set 1 meter away from the edge and bottom of the pond, respectively, and the dissolved oxygen monitoring point located in the center of the pond is set 1 meter away from the bottom of the pond.

[0009] In one embodiment, after the step of stopping liquid oxygen supply and mixing when the dissolved oxygen data rises back to a preset dissolved oxygen threshold, and the surge generator continues to run for a preset time before stopping, the method further includes: When the dissolved oxygen value at any dissolved oxygen monitoring point is lower than the warning dissolved oxygen threshold, the automatic regulating valve installed on the main liquid oxygen pipeline between the liquid oxygen tank and the dissolved oxygen cone mixer is fully opened, so that liquid oxygen is continuously injected into the dissolved oxygen cone mixer at the maximum flow rate until the dissolved oxygen at all dissolved oxygen monitoring points rises back to a safe range.

[0010] In one embodiment, the preset dissolved oxygen threshold is set in conjunction with the growth stage of the tilapia; The preset dissolved oxygen threshold for the fry stage is higher than that for the growing stage, and the preset dissolved oxygen threshold for the growing stage is higher than that for the adult stage.

[0011] In one embodiment, the surge generator is controlled to start before the liquid oxygen supply when the oxygen supply is started; after the liquid oxygen supply is stopped, the surge generator continues to run for 30 minutes to ensure that the dissolved oxygen is homogenized.

[0012] In one embodiment, the ratio of the dissolved oxygen value of the high dissolved oxygen water produced by the dissolved oxygen cone mixer to the preset dissolved oxygen value of the aquaculture water is 4:1 to 8:1.

[0013] In one embodiment, after the step of injecting the high dissolved oxygen water into the aquaculture water body so that the directional horizontal flow generated by the wave generator can cause the high dissolved oxygen water to spread evenly throughout the pond, the method further includes: calculating the dissolved oxygen range difference of multiple dissolved oxygen monitoring points in real time, and when the range difference exceeds a set threshold, controlling the wave generator to extend its running time or increase its rotation speed.

[0014] In one implementation, once the oxygen supply triggering condition is met and oxygen supply begins, the monitoring frequency of dissolved oxygen data is increased from once every 5 minutes to once every 1 minute until oxygen supply stops.

[0015] This invention achieves on-demand oxygen supply by real-time monitoring of dissolved oxygen data in the aquaculture water and activating the wave generator and liquid oxygen supersaturation mixing as needed based on oxygen supply trigger conditions. This avoids the energy waste caused by the long-term continuous operation of traditional aeration equipment. When the oxygen supply trigger conditions are met, liquid oxygen is supersaturatedly mixed with a portion of the aquaculture water in a dissolved oxygen cone mixer to generate highly oxygenated water. This water is then rapidly and evenly diffused throughout the pond using the directional horizontal flow generated by the wave generator, effectively eliminating oxygen dead zones at the bottom and corners of the pond and ensuring uniform dissolved oxygen distribution throughout the entire aquaculture water body. Simultaneously, the high purity of the liquid oxygen and the supersaturated mixing method significantly improve oxygen transfer efficiency, enabling rapid increases in dissolved oxygen levels throughout the pond even under sudden weather changes or surges in oxygen demand due to high biological loads, effectively preventing fish from surfacing or suffocating. Once the dissolved oxygen level rises to a preset threshold, the system automatically stops liquid oxygen supply and mixing, while the wave generator continues to run for a preset time to thoroughly homogenize the dissolved oxygen, further optimizing the accuracy and stability of the oxygen supply and achieving a highly efficient, energy-saving, uniform, and safe oxygen supply effect. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0017] Figure 1 A schematic diagram illustrating the steps of the oxygen supply method for high-density tilapia farming provided by the present invention; Figure 2 This is a detailed schematic diagram of step 30 of the oxygen supply method for high-density tilapia farming provided by the present invention.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0022] Traditional aeration technologies used in high-density tilapia farming, such as impeller / paddlewheel aerators, micropore aeration systems, and pure oxygen aeration systems, have limited aeration range, easily leading to dissolved oxygen dead zones at the bottom and corners of the pond, affecting fish growth and feed utilization. Furthermore, these methods have low oxygen transfer efficiency, consume significant amounts of electricity, and are unable to quickly and effectively increase dissolved oxygen levels throughout the pond during sudden weather changes or high biomass loads, posing a risk of fish surfacing or even suffocating.

[0023] For this, please refer to Figure 1 This application proposes an oxygen supply method for high-density tilapia farming, which includes the following steps: S10: Real-time monitoring of dissolved oxygen data in aquaculture water; S20: Determine whether the oxygen supply triggering condition is met based on the dissolved oxygen data; S30: When the oxygen supply triggering conditions are met, the wave generator is started, and liquid oxygen is simultaneously supersaturated and mixed with a portion of the aquaculture water in the dissolved oxygen cone mixer to generate highly oxygenated water. S40: Inject the highly oxygenated water into the aquaculture water body so that the directional horizontal flow generated by the wave generator can evenly spread the highly oxygenated water throughout the pond. S50: When the dissolved oxygen data rises back to the preset dissolved oxygen threshold, stop the liquid oxygen supply and mixing, and the surge machine will continue to run for a preset time before stopping.

[0024] Dissolved oxygen data refers to the dissolved oxygen content in aquaculture water, typically measured in real-time by sensors and expressed digitally. This data forms the basis for determining the oxygen supply needs of the water body. Oxygen supply triggering conditions refer to the specific conditions required to activate the oxygen supply system, usually related to the dissolved oxygen level of the aquaculture water. This condition is triggered when the dissolved oxygen level falls below a certain set value. A wave generator is a device that generates directional water flow, its function being to agitate the water, promote internal circulation and mixing, thereby helping high-oxygen water to diffuse evenly throughout the aquaculture water body. Liquid oxygen refers to oxygen in a liquid state, characterized by high purity and high concentration, and is often used in situations requiring rapid and efficient oxygenation. A dissolved oxygen cone mixer is a device specifically designed for the efficient mixing of gases (such as liquid oxygen) and liquids (such as aquaculture water). Its internal structure typically promotes sufficient contact between the gas and liquid phases to achieve rapid dissolution and supersaturation of oxygen.

[0025] Supersaturated mixing refers to the process under specific conditions where the amount of a gas dissolved in a liquid exceeds its saturation solubility at standard atmospheric pressure and room temperature. This method can produce water with extremely high dissolved oxygen concentrations. High-oxygenated water refers to water that, after supersaturated mixing treatment, has a dissolved oxygen content far exceeding that of ordinary aquaculture water. When this water is injected into aquaculture systems, it can rapidly increase the overall dissolved oxygen level. A preset dissolved oxygen threshold refers to the target dissolved oxygen content set during the aquaculture process to ensure the normal growth and health of tilapia. When the dissolved oxygen in the water rises back to this threshold, it indicates that the oxygen supply demand has been met.

[0026] First, the dissolved oxygen data of the aquaculture water body is monitored in real time. A dissolved oxygen sensor can be installed in the aquaculture water body, transmitting the detected dissolved oxygen data to the control system via wired or wireless means. This sensor can be fixed at a specific depth in the aquaculture water body, for example, to collect data periodically.

[0027] Secondly, the system determines whether the oxygen supply triggering condition is met based on the acquired dissolved oxygen data. After receiving the dissolved oxygen data, the control system compares it with a pre-set fixed dissolved oxygen threshold. When the detected dissolved oxygen value is lower than this fixed threshold, it is determined that the oxygen supply triggering condition is met.

[0028] When the oxygen supply trigger conditions are met, the oxygen supply process is initiated. Specifically, the control system immediately sends a start command to the wave generator, causing it to begin operation and generate a directional water flow. Simultaneously, the liquid oxygen supply system is activated, and liquid oxygen is delivered from the storage tank and mixed with a portion of the water drawn from the aquaculture water in a dissolved oxygen cone mixer. This mixer dissolves oxygen through a simple gas-liquid contact method, such as injecting liquid oxygen into the water flow through nozzles, thereby generating highly oxygenated water with a dissolved oxygen concentration higher than that of the aquaculture water.

[0029] The generated highly oxygenated water is then injected into the aquaculture water body. This highly oxygenated water is transported through pipes to the aquaculture water body, for example, into the waters near the wavemaker. The directional horizontal flow generated by the wavemaker will cause this highly oxygenated water to flow in all directions of the pond, aiming to achieve a diffusion effect and thus increase the dissolved oxygen level of the entire aquaculture water body.

[0030] Finally, when the dissolved oxygen level in the aquaculture water rises back to the preset dissolved oxygen threshold, the oxygen supply process enters the shutdown phase. The control system continuously monitors the dissolved oxygen level in the aquaculture water. When this level rises and reaches or exceeds the preset dissolved oxygen threshold, the control system immediately cuts off the liquid oxygen supply and stops the operation of the dissolved oxygen cone mixer. After the liquid oxygen supply stops, the wavemaker is set to continue running for a fixed period of time. After this period ends, the wavemaker receives a stop command and stops operating.

[0031] This embodiment, by real-time monitoring of dissolved oxygen data and initiating supersaturated liquid oxygen mixing and oxygenation based on trigger conditions, combined with the directional water flow generated by the wave generator, can rapidly and efficiently improve the overall dissolved oxygen level of the aquaculture water. This method effectively solves the problems of uneven dissolved oxygen distribution and the formation of dissolved oxygen dead zones inherent in traditional aeration technologies, ensuring balanced dissolved oxygen throughout the pond for high-density tilapia farming, reducing the risk of fish surfacing or suffocating due to oxygen deficiency, and simultaneously improving oxygen utilization efficiency.

[0032] Please see Figure 1 and Figure 2 This application further proposes step S30: supersaturating mixing of liquid oxygen with a portion of the aquaculture water in a dissolved oxygen cone mixer to generate highly oxygenated water. Specifically, this step includes: S31: sending a command to the electric proportional regulating valve installed on the main liquid oxygen pipeline between the liquid oxygen tank and the dissolved oxygen cone mixer according to the real-time oxygen deficit, opening the corresponding valve opening degree, so that liquid oxygen from the liquid oxygen tank enters the liquid oxygen inlet at the top of the dissolved oxygen cone at a set flow rate after depressurization.

[0033] The real-time oxygen deficit can be determined by monitoring the difference between dissolved oxygen data in the aquaculture water and the preset dissolved oxygen threshold, or by using a more complex model that comprehensively considers factors such as tilapia biomass, feeding amount, and water temperature.

[0034] The electric proportional control valve can be an electric ball valve, electric butterfly valve, or electric shut-off valve with precise flow control capabilities. Its opening degree is dynamically adjusted by the control system based on the real-time oxygen deficit to ensure the accuracy of liquid oxygen supply. Before entering the dissolved oxygen cone mixer, liquid oxygen typically needs to pass through a pressure reducing device to reduce its pressure from a high-pressure storage state to a pressure range suitable for mixer operation. Its actual flow rate is monitored by a flow meter, thereby achieving precise supply according to the set flow rate.

[0035] S32: Start the inlet pump of the dissolved oxygen cone to pump pond water from the pond into the inlet at the top of the dissolved oxygen cone. This inlet pump is usually a centrifugal pump or submersible pump with stable head and flow rate to ensure the continuity and stability of the water flow within the dissolved oxygen cone mixer.

[0036] S33: The aquaculture water entering the dissolved oxygen cone forms a strong swirling flow along the spiral guide vanes on the inner wall. Simultaneously, liquid oxygen is injected into the swirling water through the microporous jet ring at the top of the dissolved oxygen cone, forming a gas-liquid mixture. The spiral guide vanes are designed to increase the turbulence and residence time of the water flow, thus creating favorable conditions for the full dissolution of liquid oxygen. The microporous jet ring, by generating a large number of microbubbles, greatly increases the contact area between liquid oxygen and the aquaculture water, accelerating the mass transfer process between the gas and liquid phases and initially forming a homogeneous gas-liquid mixture.

[0037] Subsequently, the gas-liquid mixture continues to flow through the static mixing unit in the lower part of the dissolved oxygen cone, causing the gas-liquid mixture to instantly become supersaturated and dissolve, generating highly oxygenated water. The static mixing unit typically consists of a series of mixing elements fixed inside the pipe. These elements achieve efficient mixing without external power by continuously dividing, recombining, and reversing the fluid, further refining the bubbles and promoting the rapid and complete dissolution of liquid oxygen, thereby reaching a supersaturated state in a short time.

[0038] Finally, S34: The highly oxygenated water is discharged from the outlet at the bottom of the dissolved oxygen cone to a location in the aquaculture water body near the wave generator. This discharge method can fully utilize the directional horizontal flow generated by the wave generator to rapidly and evenly diffuse the highly oxygenated water throughout the aquaculture water body, avoiding excessively high or low dissolved oxygen in certain areas and ensuring a balanced dissolved oxygen level throughout the pond.

[0039] Through the above technical solution, this application can achieve precise control of liquid oxygen supply, ensuring that the supply of liquid oxygen matches the actual oxygen deficit in the aquaculture water, thus avoiding the problems of oxygen waste or insufficient oxygen supply. Simultaneously, the strong swirling flow generated by the spiral guide vanes within the dissolved oxygen cone mixer, the fine jetting from the microporous jet rings, and the efficient mixing effect of the static mixing unit greatly improve the contact efficiency and dissolution rate between liquid oxygen and the aquaculture water, enabling the liquid oxygen to instantly supersaturate and dissolve, stably generating highly oxygenated water. Furthermore, discharging the highly oxygenated water to a location near the wavemaker in the aquaculture water can, with the help of the wavemaker's propulsive action, rapidly and evenly diffuse the highly oxygenated water throughout the entire aquaculture water, effectively solving the problem of uneven local dissolved oxygen in high-density aquaculture environments, thereby providing tilapia with a stable, sufficient, and evenly distributed dissolved oxygen environment.

[0040] This application further proposes that, prior to the step of real-time detection of dissolved oxygen data in aquaculture water, multiple dissolved oxygen monitoring points are set up in the aquaculture water; and the oxygen supply triggering condition is set such that the average dissolved oxygen value of the multiple dissolved oxygen monitoring points is lower than a preset dissolved oxygen threshold.

[0041] Specifically, deploying multiple dissolved oxygen monitoring points in aquaculture water bodies aims to overcome the insufficient representativeness of single monitoring points in large or complex water bodies. By placing sensors at different locations within the aquaculture water body, more comprehensive dissolved oxygen distribution information can be obtained, preventing the overlooking of localized hypoxia or hyperxia. These dissolved oxygen monitoring points can employ various types of dissolved oxygen sensors, such as fluorescence-based dissolved oxygen sensors and electrochemical-based dissolved oxygen sensors, which can measure the dissolved oxygen concentration in the water body in real time and continuously. These sensors are connected to the central control system via data cables or wireless communication modules, transmitting the collected dissolved oxygen data to the control system for processing. During deployment, factors such as the shape and size of the water body, water flow patterns, and tilapia stocking density should be fully considered to ensure that the monitoring points cover key areas, such as dead zones and areas with dense fish populations, thereby obtaining representative dissolved oxygen data.

[0042] Meanwhile, using the average dissolved oxygen value from multiple dissolved oxygen monitoring points as the oxygen supply trigger condition provides a more representative and robust judgment basis. The control system receives data from all dissolved oxygen monitoring points and calculates the arithmetic mean of these data. Then, this average value is compared with a preset dissolved oxygen threshold. If the average value is lower than the threshold, the oxygen supply trigger condition is determined to be met. The preset dissolved oxygen threshold is a critical value set according to the dissolved oxygen requirements of tilapia at different growth stages and aquaculture management goals, ensuring that oxygen supply is initiated in a timely manner before the dissolved oxygen level drops to a level that affects the health of the fish. When abnormal fluctuations occur at a single monitoring point, the average value can effectively smooth out such fluctuations, avoiding false triggers or missed triggers caused by local, instantaneous data fluctuations.

[0043] By deploying multiple dissolved oxygen monitoring points in the aquaculture water body and using the average dissolved oxygen value of these monitoring points as the oxygen supply trigger condition, this application overcomes the problem of insufficient representativeness of data from a single monitoring point. This multi-point monitoring and average value judgment mechanism enables the system to more accurately and comprehensively grasp the dissolved oxygen status of the entire aquaculture water body, avoiding misjudgments caused by insufficient or excessive dissolved oxygen in local areas. When the average dissolved oxygen value is lower than the preset dissolved oxygen threshold, the system can promptly and accurately initiate oxygen supply, ensuring intervention before the dissolved oxygen level adversely affects tilapia growth.

[0044] This application further proposes that there are 5 dissolved oxygen monitoring points, which are located at the four corners of the pond and the center of the pond, respectively. The dissolved oxygen monitoring points located at the four corners of the pond are set 1 meter away from the edge and bottom of the pond, respectively, and the dissolved oxygen monitoring point located in the center of the pond is set 1 meter away from the bottom of the pond.

[0045] To ensure comprehensive and representative monitoring of dissolved oxygen levels in high-density aquaculture waters, this application sets the number of dissolved oxygen monitoring points at five. This number avoids both incomplete data due to too few monitoring points and increased system complexity and maintenance costs due to too many monitoring points, thus achieving a balance between monitoring coverage and system economy. This layout strategy aims to capture the typical characteristics of dissolved oxygen distribution in ponds. The four corners of the pond are usually areas with relatively weak water flow or prone to localized hypoxia, while the center of the pond represents the main water area. By placing monitoring points at these key locations, the overall trend of dissolved oxygen in the water and potential local anomalies can be effectively monitored, providing a basis for accurately determining oxygen supply needs. Setting the dissolved oxygen monitoring points at the four corners of the pond 1 meter away from the pond edge and bottom is based on considerations of tilapia activity habits and water stratification characteristics.

[0046] When tilapia are farmed at high density, their main activity areas are usually not close to the pond edges or bottom, and there may be sediment or anaerobic zones at the bottom. Setting monitoring points at a certain distance from the pond edges and bottom allows for more accurate acquisition of dissolved oxygen data from the fish's main habitat, avoiding interference from non-representative factors due to proximity to the boundaries or bottom. For dissolved oxygen monitoring points located in the center of the pond, setting them 1 meter from the bottom is also for obtaining representative dissolved oxygen data. Since the water in the center of the pond is usually deeper, setting the monitoring point in the lower middle layer effectively monitors the vertical dissolved oxygen gradient and avoids the influence of bottom sediment on sensor readings, ensuring that the measured data reflects the dissolved oxygen status of the water layer where the fish are primarily active.

[0047] The above technical solution sets the number of dissolved oxygen monitoring points to five, strategically placing them at the four corners and center of the pond. The distances of the monitoring points from the pond edge and bottom are precisely defined, making the acquired dissolved oxygen data more representative and accurate. This refined monitoring layout effectively captures potential dissolved oxygen unevenness in high-density aquaculture water, promptly identifying localized oxygen-deficient areas and avoiding potential oxygen supply delays or inadequacies based solely on average values. When the dissolved oxygen value in any key area becomes abnormal, the system responds more quickly, activating the oxygen supply mechanism to ensure that highly oxygenated water is accurately and promptly replenished to areas requiring oxygen. The directional horizontal flow generated by the wave generator promotes the uniform diffusion of highly oxygenated water throughout the pond, significantly improving the targeting and efficiency of oxygen supply and ensuring the healthy growth of tilapia in high-density aquaculture environments.

[0048] This application further proposes an emergency oxygen supply mechanism. For details, please refer to... Figure 1 The mechanism includes: S60: When the dissolved oxygen value at any dissolved oxygen monitoring point is lower than the warning dissolved oxygen threshold, the automatic regulating valve installed on the main liquid oxygen pipeline between the liquid oxygen tank and the dissolved oxygen cone mixer is fully opened, so that liquid oxygen is continuously injected into the dissolved oxygen cone mixer at the maximum flow rate until the dissolved oxygen at all dissolved oxygen monitoring points rises back to the safe range.

[0049] Specifically, when the dissolved oxygen value at any dissolved oxygen monitoring point falls below the warning dissolved oxygen threshold, it refers to the real-time dissolved oxygen data collected by the system from various dissolved oxygen monitoring points deployed in the aquaculture water body. The warning dissolved oxygen threshold is an emergency critical value lower than the conventional preset dissolved oxygen threshold, used to indicate a possible severe hypoxia in a localized area. Once the data from any monitoring point falls below this warning threshold, an emergency response is immediately triggered. This warning dissolved oxygen threshold is usually set lower than the conventional preset dissolved oxygen threshold to cope with emergencies.

[0050] The automatic regulating valve installed on the main liquid oxygen pipeline between the liquid oxygen tank and the dissolved oxygen cone mixer is fully open. This means that upon detecting an emergency oxygen deficiency, the system immediately sends a command to the automatic regulating valve controlling the flow rate of the main liquid oxygen pipeline, causing it to quickly switch from its current state to a fully open state. This automatic regulating valve can be an electric ball valve, an electric butterfly valve, or a pneumatic valve, and its full opening is designed to ensure that liquid oxygen can enter the oxygen supply system at the fastest speed and in the largest quantity.

[0051] Continuously injecting liquid oxygen into the dissolved oxygen cone mixer at maximum flow rate means that, with the automatic regulating valve fully open, liquid oxygen is continuously supplied to the dissolved oxygen cone mixer at its own pressure or with auxiliary pressurization, at the maximum delivery rate achievable by the system. This aims to maximize the oxygen supply capacity of the dissolved oxygen cone mixer, enabling it to rapidly generate large quantities of highly oxygenated water.

[0052] The "until dissolved oxygen levels at all monitoring points return to a safe range" means that after the emergency oxygen supply measures are activated, the system will continuously and closely monitor the real-time data from all the aforementioned dissolved oxygen monitoring points. The safe range is typically set as a dissolved oxygen level higher than the warning dissolved oxygen threshold but sufficient to ensure the normal physiological activities of the tilapia. Only when the dissolved oxygen values ​​at all monitoring points have recovered and stabilized above this safe range will the emergency oxygen supply mode be deactivated, and the automatic regulating valve will close or return to normal control to avoid over-oxygenation. This safe range is higher than the warning dissolved oxygen threshold, for example, not lower than 4.0 mg / L.

[0053] Using the above technical solution, when the dissolved oxygen level in a certain area drops sharply below the warning dissolved oxygen threshold, the system can quickly identify and activate the emergency oxygen supply mechanism, rather than waiting for the overall average dissolved oxygen value to decrease. This instant response mechanism ensures that liquid oxygen is injected into the dissolved oxygen cone mixer at maximum flow rate by fully opening the automatic regulating valve on the main liquid oxygen pipeline, thereby generating and delivering a large amount of high dissolved oxygen water to the aquaculture water body in the shortest possible time, rapidly increasing the dissolved oxygen level of the local and even the entire water body.

[0054] In response, this application further proposes a setting that links the preset dissolved oxygen threshold with the growth stage of tilapia; wherein the preset dissolved oxygen threshold during the fry stage is higher than the preset dissolved oxygen threshold during the growing stage, and the preset dissolved oxygen threshold during the growing stage is higher than the preset dissolved oxygen threshold during the adult stage.

[0055] Specifically, the preset dissolved oxygen threshold is a key parameter used to determine whether oxygen supply needs to be activated. Linking this threshold to the tilapia's growth stage means that it is not fixed but dynamically adjusted according to the specific growth cycle of the tilapia. For example, the growth stage information of the current batch of tilapia can be manually input, or the current growth stage can be automatically identified through an integrated growth monitoring system (such as image recognition-based fish size estimation, feed amount matching with growth curves, etc.). Based on the acquired growth stage information, the control system queries or calculates the optimal dissolved oxygen threshold corresponding to the current stage from a preset parameter table and uses it as the basis for triggering oxygen supply. This linked setting ensures that the oxygen supply strategy can adapt to the physiological needs of tilapia at different life stages.

[0056] Meanwhile, this setting clarifies the relative relationship of dissolved oxygen thresholds at different growth stages. Tilapia fry have a high metabolic rate, low tolerance to hypoxia, and are more sensitive to changes in water quality, thus requiring higher dissolved oxygen levels to ensure healthy growth and survival. As tilapia enter the rearing and adult stages, their body size increases, their adaptability to the environment strengthens, their oxygen consumption per unit body weight stabilizes or slightly decreases, and their tolerance to low dissolved oxygen levels improves. Therefore, the preset dissolved oxygen threshold can be appropriately lowered to optimize oxygen supply efficiency while ensuring fish health. For example, the threshold can be set at 5.5 mg / L for fry, 5.0 mg / L for rearing, and 4.5 mg / L for adults. This phased threshold setting is an optimization based on the physiological characteristics of tilapia and practical farming experience, aiming to achieve precise oxygen supply.

[0057] The aforementioned technical solution links the preset dissolved oxygen threshold to the growth stages of tilapia, clarifying the decreasing relationship of the dissolved oxygen threshold at different growth stages. This allows the oxygen supply system to be precisely controlled according to the actual physiological needs of the tilapia. During the fry stage, due to their high dissolved oxygen requirements and sensitivity to hypoxia, setting a higher dissolved oxygen threshold effectively ensures the survival rate and healthy growth of the fry. As tilapia enter the rearing and adult stages, their tolerance to dissolved oxygen increases. Appropriately lowering the dissolved oxygen threshold meets their growth needs while avoiding unnecessary over-oxygenation, thus effectively saving liquid oxygen consumption and operating costs. This dynamic and refined dissolved oxygen management strategy significantly improves the economic and environmental benefits of high-density tilapia farming, promotes the healthy and rapid growth of tilapia, and reduces farming risks.

[0058] Please see Figure 1 This application further proposes controlling the surge generator to start before the liquid oxygen supply when the oxygen supply is started; after the liquid oxygen supply is stopped, the surge generator continues to run for 30 minutes to ensure the homogenization of dissolved oxygen.

[0059] Specifically, to ensure that highly oxygenated water can rapidly and evenly diffuse throughout the aquaculture pond when oxygen supply is initiated, this method uses a control system to activate the wave generator first after detecting that the oxygen supply triggering conditions are met. The wave generator runs for a period of time, such as several seconds to tens of seconds, before the liquid oxygen supply is activated, aiming to pre-establish a stable directional horizontal water flow in the pond. This strategy of pre-activating the wave generator effectively avoids localized accumulation of highly oxygenated water due to insufficient water flow at the moment of injection, thereby promoting faster and more even diffusion throughout the pond and improving the efficiency of initial oxygen diffusion.

[0060] Furthermore, to further optimize the uniformity of dissolved oxygen in the aquaculture water, even after dissolved oxygen levels rise to a preset threshold and liquid oxygen supply is stopped, slight dissolved oxygen concentration gradients may still exist. To completely eliminate these gradients and ensure a highly consistent dissolved oxygen level throughout the entire aquaculture water body, the wave generator is set to continue operating for a preset period, such as 30 minutes, after the liquid oxygen supply stops. This continuous operating time is based on experience or simulation calculations and is sufficient to ensure that convection and mixing within the water body can proceed sufficiently after the external oxygen input is stopped, thereby achieving complete homogenization of dissolved oxygen.

[0061] This application further proposes that the ratio of the dissolved oxygen value of the high dissolved oxygen water produced by the dissolved oxygen cone mixer to the preset dissolved oxygen value of the aquaculture water is 4:1 to 8:1.

[0062] The goal is to optimize the dissolution and diffusion efficiency of oxygen in aquaculture water by controlling the ratio of dissolved oxygen in the high-oxygen water to the preset dissolved oxygen value of the aquaculture water within the range of 4:1 to 8:1. This ratio can be achieved through various methods. For example, the flow rate of liquid oxygen entering the dissolved oxygen cone can be adjusted by precisely controlling the opening of the electric proportional regulating valve installed on the main liquid oxygen pipeline between the liquid oxygen tank and the dissolved oxygen cone mixer, thereby changing the dissolved oxygen concentration of the high-oxygen water. Simultaneously, the flow rate of the inlet pump of the dissolved oxygen cone can be adjusted to control the amount of aquaculture water entering the dissolved oxygen cone, thus affecting the gas-liquid mixing ratio and dissolution efficiency. Furthermore, the internal structural design of the dissolved oxygen cone, such as the spiral guide vanes, microporous jet rings, and static mixing unit, also significantly impacts the gas-liquid mixing and dissolution effects. In actual operation, a dissolved oxygen sensor can be installed at the outlet of the dissolved oxygen cone to monitor the dissolved oxygen value of the high-oxygen water in real time. Combined with the preset dissolved oxygen value of the aquaculture water, the control system can provide feedback adjustments to ensure that the ratio is maintained within the target range. For example, the dissolved oxygen value of the high dissolved oxygen water is 20~40 mg / L, and the preset dissolved oxygen value of the aquaculture water is 4.5~5.5 mg / L.

[0063] By employing the aforementioned technical solution, the ratio of dissolved oxygen value in the high-oxygenated water produced by the dissolved oxygen cone mixer to the preset dissolved oxygen value in the aquaculture water is precisely controlled within the range of 4:1 to 8:1. This ensures that the high-oxygenated water injected into the aquaculture water has a suitable oxygen concentration gradient. When this ratio is within this range, oxygen in the high-oxygenated water can diffuse and dissolve efficiently and rapidly into the aquaculture water, thereby significantly accelerating the recovery rate of dissolved oxygen levels in the aquaculture water. If the ratio is too low, the oxygen concentration gradient will be insufficient, leading to low oxygen transfer efficiency and slow dissolved oxygen recovery, which may not be able to meet the oxygen requirements of tilapia in time. If the ratio is too high, it may cause excessive consumption of liquid oxygen, increasing operating costs, and excessively high local dissolved oxygen concentrations may cause unnecessary stress to tilapia. Therefore, by precisely setting and controlling this ratio, this application can achieve efficient, economical, and safe dissolved oxygen supplementation, raising the dissolved oxygen level of the aquaculture water to a suitable range in the shortest possible time, while avoiding unnecessary resource waste and ensuring the healthy growth of tilapia.

[0064] Please see Figure 1 This application further proposes an oxygen supply method for high-density tilapia farming. Based on real-time detection of dissolved oxygen data in the farming water, the method also includes S70: real-time calculation of the dissolved oxygen range of multiple dissolved oxygen monitoring points. When the range exceeds a set threshold, the wave generator is controlled to extend its running time or increase its speed.

[0065] Specifically, dissolved oxygen range refers to the difference between the highest and lowest dissolved oxygen values ​​at multiple dissolved oxygen monitoring points at the same time. The purpose of real-time calculation of dissolved oxygen range is to assess the uniformity of dissolved oxygen distribution in aquaculture water. This can be achieved by periodically acquiring real-time dissolved oxygen data from various monitoring points through a control system, sorting these data, identifying the maximum and minimum values, and calculating their difference. This calculation frequency can be configured according to actual needs, such as once per minute or every five minutes.

[0066] The threshold setting is a preset value used to determine whether the uniformity of dissolved oxygen distribution has reached an acceptable range. This threshold can be set based on the tilapia's stocking density, growth stage, water volume, and empirical values. When the real-time calculated dissolved oxygen range exceeds this threshold, it indicates that the uneven distribution of dissolved oxygen in the water has reached a level requiring intervention.

[0067] The primary function of a wave generator is to produce directional horizontal flow, promoting water circulation and dissolved oxygen diffusion. When an excessively large dissolved oxygen difference is detected, the control system sends a command to the wave generator's controller to extend its operating time or increase its rotation speed. Extending the operating time can be achieved by adding an extra period to the existing operating schedule, such as continuing operation for 30 minutes or 1 hour after a normal shutdown. Increasing the rotation speed requires the wave generator to have variable frequency speed control functionality. The control system, based on the degree of the oxygen difference, increases the rotation speed from the current value to a preset higher level to produce a stronger propulsive effect.

[0068] Using the above technical solution, this method can effectively identify potential localized dissolved oxygen unevenness in aquaculture water. When the uneven dissolved oxygen distribution is detected to the point where intervention is necessary, extending the operating time or increasing the rotation speed of the wave generator can significantly enhance the mixing and flow effects of the water, accelerating the uniform diffusion of high-oxygen water throughout the aquaculture water body.

[0069] This application further proposes that, once the oxygen supply triggering conditions are met and oxygen supply begins, the monitoring frequency of dissolved oxygen data be increased from once every 5 minutes to once every 1 minute, until oxygen supply stops.

[0070] Specifically, the monitoring frequency of dissolved oxygen data refers to the number of times dissolved oxygen data in aquaculture water is collected and recorded per unit of time. The standard frequency is usually set to meet daily monitoring needs without excessively consuming system resources. Increasing the monitoring frequency means increasing the density of data collection during specific critical periods to obtain more refined and real-time information on dissolved oxygen changes. This can be achieved by controlling the data acquisition module or data processing unit of the dissolved oxygen sensor. For example, when the oxygen supply system starts, the control system can send a command to the dissolved oxygen sensor to adjust its data output interval from 5 minutes to 1 minute. Alternatively, the data acquisition system can continuously collect data at a high frequency (e.g., once per minute), but only upload or record data every 5 minutes under normal conditions, while uploading or recording all high-frequency data during oxygen supply. This adjustment can be a software-level parameter configuration or a hardware-level sampling rate switch. The purpose of increasing the monitoring frequency is to more quickly capture the changing trends and specific values ​​of dissolved oxygen data during the oxygen supply phase when dissolved oxygen levels fluctuate drastically, providing a more timely and accurate basis for subsequent adjustments to the oxygen supply strategy.

[0071] "Until oxygen supply stops" refers to the system terminating the supply of liquid oxygen and the mixing process in the aquaculture water according to a preset logical judgment. This typically occurs when the dissolved oxygen data in the aquaculture water recovers and stabilizes above the preset dissolved oxygen threshold. The judgment logic for stopping oxygen supply is usually executed by the control system. When the monitored dissolved oxygen data remains above the preset dissolved oxygen threshold for a period of time (e.g., above the threshold for 5 consecutive minutes), the control system issues a command to close the liquid oxygen supply valve and stop the operation of the dissolved oxygen cone mixer. After the oxygen supply stop command is issued, the encrypted monitoring frequency will return to the normal frequency. This clarifies the duration of the encrypted monitoring frequency, ensuring that high-precision dissolved oxygen data monitoring is maintained throughout the entire oxygen supply cycle, from start to stop, thereby comprehensively understanding the oxygen supply effect and the dissolved oxygen status of the water. After oxygen supply stops, the monitoring frequency returns to once every 5 minutes.

[0072] Through the above technical solution, after the oxygen supply triggering conditions are met and oxygen supply begins, the monitoring frequency of dissolved oxygen data is increased from once every 5 minutes to once every 1 minute until oxygen supply stops. This application can significantly improve the real-time performance and accuracy of dissolved oxygen data during the oxygen supply process. During the oxygen supply phase where dissolved oxygen levels may change rapidly, more frequent data acquisition allows the system to promptly capture subtle fluctuations and trends in dissolved oxygen, thus providing more accurate feedback information to the control system. This helps the oxygen supply system to adjust the liquid oxygen supply and mixing intensity more quickly and accurately, avoiding over-oxygenation or under-oxygenation due to data lag, ensuring that the dissolved oxygen in the aquaculture water remains within the suitable growth range for tilapia, effectively improving oxygen supply efficiency and aquaculture benefits.

[0073] The above description is merely an exemplary embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. An oxygen supply method for high-density tilapia farming, characterized in that, The oxygen supply method for high-density tilapia farming includes the following steps: Real-time monitoring of dissolved oxygen data in aquaculture water; Determine whether the oxygen supply triggering conditions are met based on the dissolved oxygen data; When the oxygen supply triggering conditions are met, the wave generator is activated, and liquid oxygen is simultaneously supersaturated and mixed with a portion of the aquaculture water in the dissolved oxygen cone mixer to generate highly oxygenated water. The highly oxygenated water is injected into the aquaculture water body so that the directional horizontal flow generated by the wave generator can evenly spread the highly oxygenated water throughout the entire pond. When the dissolved oxygen data rises back to the preset dissolved oxygen threshold, the liquid oxygen supply and mixing are stopped, and the wave generator continues to run for a preset time before stopping.

2. The oxygen supply method for high-density tilapia farming as described in claim 1, characterized in that, The steps involved in supersaturating the mixing of liquid oxygen with a portion of aquaculture water in a dissolved oxygen cone mixer to generate highly oxygenated water include: Based on the real-time oxygen deficit, a command is sent to the electric proportional regulating valve installed on the main liquid oxygen pipeline between the liquid oxygen tank and the dissolved oxygen cone mixer to open the corresponding valve opening, so that liquid oxygen enters the liquid oxygen inlet at the top of the dissolved oxygen cone from the liquid oxygen tank after depressurization at a set flow rate. Start the inlet pump of the dissolved oxygen cone to pump pond water from the pond into the inlet at the top of the dissolved oxygen cone; The aquaculture water entering the dissolved oxygen cone forms a strong swirling flow along the spiral guide vanes on the inner wall. At the same time, liquid oxygen is injected into the swirling water through the microporous jet ring at the top of the dissolved oxygen cone to form a gas-liquid mixture. The gas-liquid mixture continues to flow through the static mixing unit in the lower part of the dissolved oxygen cone, so that the gas-liquid mixture is instantly supersaturated and dissolved to generate highly oxygenated water. The highly oxygenated water is discharged from the outlet at the bottom of the dissolved oxygen cone to a location in the aquaculture water body near the wave generator.

3. The oxygen supply method for high-density tilapia farming as described in claim 1, characterized in that, The steps preceding the real-time monitoring of dissolved oxygen data in aquaculture water also include: Multiple dissolved oxygen monitoring points are set up in the aquaculture water body; the oxygen supply triggering condition is that the average dissolved oxygen value of the multiple dissolved oxygen monitoring points is lower than the preset dissolved oxygen threshold.

4. The oxygen supply method for high-density tilapia farming as described in claim 3, characterized in that, There are 5 dissolved oxygen monitoring points, which are located at the four corners of the pond and the center of the pond. The dissolved oxygen monitoring points at the four corners of the pond are set 1 meter away from the edge and bottom of the pond, respectively, and the dissolved oxygen monitoring point at the center of the pond is set 1 meter away from the bottom of the pond.

5. The oxygen supply method for high-density tilapia farming as described in claim 3, characterized in that, When the dissolved oxygen level rises back to the preset dissolved oxygen threshold, the liquid oxygen supply and mixing are stopped. After the wave generator continues to run for a preset time and then stops, the following steps are also included: When the dissolved oxygen value at any dissolved oxygen monitoring point is lower than the warning dissolved oxygen threshold, the automatic regulating valve installed on the main liquid oxygen pipeline between the liquid oxygen tank and the dissolved oxygen cone mixer is fully opened, so that liquid oxygen is continuously injected into the dissolved oxygen cone mixer at the maximum flow rate until the dissolved oxygen at all dissolved oxygen monitoring points rises back to a safe range.

6. The oxygen supply method for high-density tilapia farming as described in claim 3, characterized in that, The preset dissolved oxygen threshold is set in conjunction with the growth stage of the tilapia. The preset dissolved oxygen threshold for the fry stage is higher than that for the growing stage, and the preset dissolved oxygen threshold for the growing stage is higher than that for the adult stage.

7. The oxygen supply method for high-density tilapia farming as described in claim 1 or 2, characterized in that, The surge generator is controlled to start before the liquid oxygen supply when the oxygen supply is started; after the liquid oxygen supply is stopped, the surge generator continues to run for 30 minutes to ensure that the dissolved oxygen is homogenized.

8. The oxygen supply method for high-density tilapia farming as described in claim 1 or 3, characterized in that, The dissolved oxygen value of the high dissolved oxygen water produced by the dissolved oxygen cone mixer is 4:1 to 8:1, which is the ratio of the dissolved oxygen value to the preset dissolved oxygen value of the aquaculture water.

9. The oxygen supply method for high-density tilapia farming as described in claim 3, characterized in that, After the step of injecting the highly oxygenated water into the aquaculture water body so that the directional horizontal flow generated by the wave generator can evenly diffuse the highly oxygenated water throughout the pond, the method further includes: The dissolved oxygen range at multiple dissolved oxygen monitoring points is calculated in real time. When the range exceeds the set threshold, the surge machine is controlled to extend its running time or increase its speed.

10. The oxygen supply method for high-density tilapia farming as described in claim 1, characterized in that, Once the oxygen supply triggering conditions are met and oxygen supply begins, the frequency of dissolved oxygen data monitoring will be increased from once every 5 minutes to once every 1 minute until oxygen supply stops.

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