Pure oxygen supply system for specialty freshwater fry culture

Abstract

The utility model relates to a kind of pure oxygen supply system for characteristic freshwater fry culture, belong to aquaculture technical field, mainly solve the problem of traditional system oxygen supply pressure fluctuation, dissolved oxygen distribution is uneven, circulating water oxygen compensation loss.The system includes oxygen generator unit, microporous aeration device, rearing pond unit and circulating water treatment unit: oxygen generator unit adopts shunt molecular sieve adsorption tower and oxygen storage tank with pressure feedback, realizes continuous oxygen supply by double-path switching valve;The main pipe end of microporous aeration device is bifurcated into helical branch microporous pipe;Circulating water treatment unit is supplemented with oxygen by Venturi oxygen-adding branch pipe to the pipeline between fluidized bed biological filter and ultraviolet-ozone sterilizer, and pneumatic diaphragm regulating valve is dynamically controlled opening degree based on distributed oxygen sensor signal.The system optimizes dissolved oxygen uniformity by spiral aeration layout, can stably maintain fry culture water dissolved oxygen concentration, reduce energy consumption and prolong equipment maintenance cycle, suitable for high-density characteristic freshwater fry scale culture.

Description

Technical Field

[0001] This utility model relates to the field of aquaculture. More specifically, this utility model relates to a pure oxygen supply system for the cultivation of specialty freshwater fish fry. Background Technology

[0002] In the cultivation and rearing of specialty freshwater fish fry, maintaining a stable dissolved oxygen concentration in the water is a key factor affecting the survival rate and growth efficiency of the fry. Traditional pure oxygen supply systems typically combine a single molecular sieve adsorption tower with linearly arranged aeration devices, which presents several technical bottlenecks in practical applications. First, the molecular sieve adsorption tower is prone to fluctuations in oxygen output pressure when switching between adsorption and desorption states. Especially under continuous operation, the regeneration phase of the adsorption tower can cause oxygen supply interruptions or sudden drops in concentration, making it difficult to meet the continuous oxygen requirements of fish fry rearing. The root cause of this problem is that a single-tower structure cannot achieve a dynamic balance between adsorption and regeneration processes. Adding parallel tower groups presents technical challenges such as uneven gas distribution and sluggish response of switching valves, making it difficult to improve system stability. Secondly, conventional aeration devices often employ linear, branching microporous pipes evenly distributed at the bottom of the pond. This layout easily creates a dissolved oxygen distribution gradient in circular rearing ponds. Due to the circulation effect caused by the circular structure, the oxygen bubbles released from the linearly arranged aeration holes are carried away by the water flow as they rise, resulting in a higher dissolved oxygen concentration in the central area of ​​the pond and insufficient oxygen in the peripheral areas, creating localized oxygen-deficient dead zones. Furthermore, the fixed design of the aeration hole diameter and spacing makes it difficult to adapt to the changing oxygen consumption of fry at different growth stages, easily leading to over-oxygenation in the juvenile stage or under-oxygenation in the adult stage. Adjusting aeration parameters requires manual intervention in the pipe layout, which is cumbersome and difficult to dynamically optimize. In the circulating water treatment process, existing systems generally adopt a series configuration of "microfilter-biological filter-ultraviolet sterilizer," but the synergistic efficiency of each unit is low. Microfilters have a single mesh size, limiting their effectiveness in retaining suspended particles. Unfiltered fine organic matter entering the biological filter easily clogs the filter media, shortening its lifespan. While ultraviolet sterilization achieves sterilization requirements, the lack of an effective oxygen compensation mechanism during the return water process results in dissolved oxygen levels below the cultivation requirements, necessitating additional aeration equipment and increasing energy consumption. Furthermore, traditional systems often use independently controlled water level and flow regulation devices, making it difficult to achieve coordinated control between the water treatment unit and the oxygen supply system based on real-time water quality changes, leading to resource waste. Maintenance issues with aeration devices are also prominent. After prolonged use, the pores of microporous aeration pipes are easily clogged by microbial films or calcifications. Conventional backwashing methods, which often use unidirectional water flow, have limited effectiveness in removing deposits from the pipe walls. High-pressure backwashing, on the other hand, suffers from problems such as mismatch between the water flow direction and the aeration pipe structure, and uneven pressure distribution, resulting in some micropores not being completely cleared, affecting the sustainability of aeration efficiency. Furthermore, an improperly designed switching mechanism between the backwashing pipeline and the main oxygen supply pipeline can also cause gas leaks or water hammer effects, threatening system safety. The root cause of the aforementioned technical deficiencies lies in the lack of integrated design for oxygen supply, water treatment, and the fluid environment within the tank in traditional systems. The parameters of each subsystem have low matching accuracy, and control methods rely on experience-based operation. For example, the working cycle of the molecular sieve adsorption tower fails to establish a dynamic correlation with aeration requirements, and the oxygen content of the return water from the water treatment unit does not form a compensation mechanism with the main oxygen supply system, resulting in low overall system energy efficiency. Furthermore, when dealing with high-density fish fry cultivation, existing systems struggle to simultaneously ensure dissolved oxygen uniformity, water quality cleanliness, and equipment operational stability, thus hindering the improvement of large-scale fry production efficiency. Summary of the Invention

[0003] One object of this invention is to solve at least the problems described above and to provide at least the advantages that will be explained later.

[0004] This utility model solves the following technical problems: Traditional fish fry rearing systems suffer from problems such as interrupted oxygen supply during the regeneration stage of the oxygen generator adsorption tower, uneven dissolved oxygen distribution in the aeration device, lack of oxygen compensation in the circulating water treatment unit, and low backwashing efficiency, resulting in unstable system operation, high energy consumption, and difficult maintenance. Conventional circular culture ponds suffer from water flow disturbances and dissolved oxygen gradient differences due to the mismatch between pond size and aeration pipe layout. Additionally, algae easily grow on the pond walls, affecting water quality stability. Existing microfiltration machines have single-layer filter screens that are prone to clogging and insufficient specific surface area of ​​biological filter packing, resulting in low suspended solids retention rate and poor nitrifying bacteria loading efficiency, which affects water treatment performance. In traditional backwashing pipelines, the water flow direction is parallel to the aeration direction, resulting in uneven flushing pressure distribution. This makes it impossible to completely remove microporous deposits, and pressure surges are easily triggered when switching valves. The connection between the backwash branch and the microporous tube is prone to leakage due to the reverse impact of water flow, and the valve core surface is prone to scaling, which can lead to seal failure and affect the reliability of backwashing. After long-term use, microbial films easily grow on the surface of microporous tubes. At the same time, the coating lacks environmental responsiveness, resulting in decreased aeration efficiency and inability to adapt to fluctuations in water pH. Traditional dissolved oxygen probes have low detection accuracy in complex flow fields, their surfaces are easily contaminated, and their placement is often unreasonable, making it difficult to achieve precise control of dissolved oxygen concentration. To achieve the above objectives and advantages, this utility model provides a pure oxygen supply system for the cultivation of specialty freshwater fish fry, including an oxygen generator, a microporous aeration device, a cultivation pond unit, and a circulating water treatment unit. The oxygen generator unit includes two sets of molecular sieve adsorption towers, an air compressor, and an oxygen storage tank with pressure feedback, all arranged in parallel. The outlet of the air compressor is connected to the inlet of the two sets of molecular sieve adsorption towers through a dual-path switching valve. The outlet of the molecular sieve adsorption tower is connected to the oxygen storage tank through a manifold. The outlet of the oxygen storage tank is equipped with a proportional regulating valve that is linked to the dissolved oxygen concentration. The microporous aeration device includes a main pipe and branch microporous pipes. The inlet of the main pipe is connected to the proportional regulating valve of the outlet of the oxygen storage tank. The end of the main pipe extends to the bottom of the cultivation tank unit and connects with 10 spiral branch microporous pipes. The spacing between adjacent branch microporous pipes is 1 / 8 to 1 / 10 of the tank diameter and maintains a spacing of 18±2cm. The surface of the branch microporous pipes has 0.2±0.05mm aeration holes at a 120° angle. The hole spacing is proportional to the branch microporous pipe spacing in a ratio of 1:1.5. The circulating water treatment unit includes a drum-type microfilter, a fluidized bed biofilter, and an ultraviolet-ozone composite sterilizer arranged in series. The inlet of the microfilter is connected to the center of the bottom of the pool through a siphon drain pipe, and its outlet is connected to the inlet of the sterilizer through the biofilter. The outlet of the sterilizer is connected to the inlet of the cultivation pool through a jet nozzle. The pipeline between the fluidized bed biofilter and the sterilizer is equipped with a Venturi oxygenation branch pipe that connects to the outlet of the oxygen storage tank. This branch pipe is equipped with a pneumatic membrane regulating valve, and the opening degree of the pneumatic membrane regulating valve is linked to the signal of the distributed oxygen sensor installed in the cultivation tank. Preferably, the cultivation pool unit of this utility model is formed by splicing modified PP plates to form a compound circular pool group with a diameter gradient. The diameter of a single pool is 1.4-1.6 meters and is matched with the spacing of the branch microporous tubes in a 1:10 ratio. The slope of the pool bottom is adjusted to 8±1° and a spiral guide channel is provided with a channel depth of 2-3 mm. The roughness of the inner wall of the pool is Ra1.2±0.2μm and the surface is coated with a titanium dioxide photocatalytic coating. Preferably, the filter screen of the roller microfilter of this utility model has a double-layer gradient mesh structure, with an inner layer of 200 mesh and an outer layer of 300 mesh. The packing material of the fluidized bed biofilter adopts a graphene-based porous ceramic carrier, which increases the specific surface area to 1000-1500 m² / m³ and loads nitrifying bacteria microcapsules in the pores.

[0005] Preferably, the end of the branch microporous tube is connected to a backwash branch, which is connected to a high-pressure water source and an oxygen storage tank outlet respectively via a quick-connect three-way valve. The backwash water flow direction is arranged in the opposite direction to the aeration direction. The main pipeline is equipped with a drain valve and an oxygen valve. When oxygen is supplied through the branch microporous tube, the oxygen valve is open and the drain valve is closed. When backwashing the branch microporous tube, the oxygen valve is closed and the drain valve is open. Preferably, the quick-connect three-way valve of the backwash branch of this utility model integrates a pressure self-locking mechanism, and its high-pressure water source connection end is equipped with a vortex pulse generator. Preferably, a conical diffusion check valve is provided at the connection between the backwash branch and the branch microporous tube of this invention, and the valve core surface is covered with a hydrophobic silicon carbide coating. Preferably, the nano-ceramic coating on the outer wall of the branched microporous tube of this invention contains silver ion slow-release particles with a particle size of 2-5 μm, and the pores of the coating are filled with pH-responsive hydrogel. Preferably, the distributed oxygen sensor array of this utility model adopts a fiber optic dissolved oxygen probe group, with the probes distributed along the spiral branch microporous tube in accordance with the golden ratio, with a spacing of 25±2cm, and the probe shell is equipped with a self-cleaning brush ring.

[0006] This utility model has at least the following beneficial effects: By using a parallel molecular sieve adsorption tower and a dual-path switching valve design, the adsorption-regeneration process can be continuously and alternately operated, avoiding fluctuations in oxygen supply pressure. The spiral aeration pipe array combined with the Venturi oxygenation branch pipe can simultaneously improve the uniformity of dissolved oxygen in the pool and the oxygenation efficiency of circulating water. The reverse backwashing branch design significantly improves the micropore unblocking effect and reduces the maintenance frequency. The diameter gradient duplex pool group and the spiral guide channel work together to optimize the water circulation path. Combined with the self-cleaning function of the titanium dioxide coating, it reduces algae adhesion and enhances dissolved oxygen diffusion efficiency. The matching ratio of the pool bottom slope and the spacing of the microporous tubes can suppress local dissolved oxygen accumulation. The dual-layer gradient filter achieves graded interception of suspended solids, reducing the risk of filter clogging; the graphene-based porous ceramic carrier, through high specific surface area and microcapsule loading technology, enhances the colonization density and metabolic activity of nitrifying bacteria, extending the service life of the biofilter. The vortex pulse generator produces periodic high-pressure water flow, which, combined with a 135° reverse flushing angle, effectively strips the biofilm from the pipe wall; the pressure self-locking mechanism prevents overpressure from damaging the microporous structure, ensuring that the backflushing process is safe and controllable. The conical diffuser check valve reduces reverse flow resistance through flow channel optimization, and the hydrophobic coating reduces the probability of scale buildup on the valve core, improving sealing performance by more than 50% and preventing gas leakage and water hammer effect during backwashing. Silver ion slow-release particles continuously inhibit the growth of microbial films, and pH-responsive hydrogels dynamically adjust pore permeability according to the acidity or alkalinity of the water, thereby steadily increasing aeration efficiency by 20%-30% and extending the service life of microporous tubes. The fiber optic probes are arranged according to the golden ratio to accurately capture changes in dissolved oxygen gradient in the spiral flow field; the self-cleaning brush ring automatically removes dirt from the probe surface, reducing the detection error rate to ±0.1mg / L, providing a reliable data basis for closed-loop control of oxygen concentration.

[0007] Other advantages, objectives and features of this invention will be partly apparent from the following description, and partly understood by those skilled in the art through study and practice of this invention. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of the structure of this utility model.

[0009] 1. Air compressor; 2. Molecular sieve adsorption tower; 3. Oxygen storage tank; 4. Culture tank; 5. Roller microfilter; 6. Fluidized bed biofilter; 7. Venturi oxygen supply branch pipe; 8. Sterilizer. Detailed Implementation

[0010] The present invention will now be described in further detail with reference to the accompanying drawings, so that those skilled in the art can implement it based on the description.

[0011] It should be understood that terms such as “having,” “comprising,” and “including” as used herein do not exclude the presence or addition of one or more other elements or combinations thereof.

[0012] It should be noted that, unless otherwise specified, the experimental methods described in the following embodiments are conventional methods, and the reagents and materials described are commercially available. In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "setting" should be interpreted broadly. For example, they can refer to fixed connection or setting, detachable connection or setting, or integral connection or setting. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. The terms "lateral," "longitudinal," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0013] like Figure 1 As shown, a pure oxygen supply system for the cultivation of specialty freshwater fish fry includes an oxygen generator, a microporous aeration device, four cultivation tank units, and a circulating water treatment unit. The oxygen generator unit includes two sets of molecular sieve adsorption towers 2 arranged in parallel, an air compressor 1, and an oxygen storage tank 3 with pressure feedback. The outlet of the air compressor 1 is connected to the inlet of the two sets of molecular sieve adsorption towers 2 through a dual-path switching valve. The outlet of the molecular sieve adsorption tower 2 is connected to the oxygen storage tank 3 through a manifold. The outlet of the oxygen storage tank 3 is equipped with a proportional regulating valve that is linked to the dissolved oxygen concentration. The microporous aeration device includes a main pipe and branch microporous pipes. The inlet of the main pipe is connected to the proportional regulating valve at the outlet of the oxygen storage tank 3. The end of the main pipe extends to the bottom of the cultivation tank 4 unit and connects with 10 spiral branch microporous pipes. The spacing between adjacent branch microporous pipes is 1 / 8 to 1 / 10 of the tank diameter and maintains a spacing of 18±2cm. The surface of the branch microporous pipes has 0.2±0.05mm aeration holes staggered at a 120° angle. The hole spacing is proportional to the branch microporous pipe spacing in a ratio of 1:1.5. The circulating water treatment unit includes a drum-type microfilter 5, a fluidized bed biological filter 6 and an ultraviolet-ozone composite sterilizer 8 arranged in series. The inlet of the microfilter is connected to the center of the bottom of the pool through a siphon-type sewage pipe, and its outlet is connected to the inlet of the sterilizer 8 through the biological filter. The outlet of the sterilizer 8 is connected to the inlet of the cultivation tank 4 through a jet nozzle. The pipeline between the fluidized bed biofilter 6 and the sterilizer 8 is equipped with a Venturi oxygenation branch pipe 7 that connects to the outlet of the oxygen storage tank 3. This branch pipe is equipped with a pneumatic membrane regulating valve, and the opening degree of the pneumatic membrane regulating valve is linked to the signal of the distributed oxygen sensor installed in the cultivation tank 4.

[0014] The oxygen generator unit can include two sets of parallel molecular sieve adsorption towers 2, with 13X type zeolite molecular sieves as the adsorbent. The air compressor 1 can be a screw compressor, with its outlet connected to the inlets of the two adsorption towers via a dual-way switching valve. The switching valve response time can be set to 3-5 seconds. The oxygen storage tank 3 can be equipped with a pressure sensor to monitor the tank pressure in real time and maintain it within the range of 0.6-0.8 MPa. The opening of the outlet proportional control valve can be dynamically adjusted based on the dissolved oxygen concentration sensor signal. When the dissolved oxygen concentration in the tank is below 10 mg / L, the valve opening increases to 50%-70%. During assembly, the molecular sieve adsorption tower 2 can be vertically installed on the side of the oxygen storage tank 3. The dual-way switching valve is located on the horizontal pipe section between the compressor outlet and the adsorption tower inlet. The bottom of the oxygen storage tank 3 is connected to the proportional regulating valve via a flange. During operation, when one set of adsorption towers reaches saturation pressure, the switching valve automatically switches to the other set of adsorption towers to ensure continuous oxygen output. The main pipe can be made of polyurethane elastic material, extending to the bottom of the cultivation tank 4 and then branching into 10 microporous pipes. The outer diameter of the microporous pipes can be 8mm, and the spiral branching spacing can be set to 1 / 8 of the tank diameter (18.75cm for a tank diameter of 1.5 meters). The aeration holes can be staggered at a 120° angle, with a hole diameter controlled between 0.15-0.25mm, and the hole spacing can be set to 27±3cm (in a 1:1.5 ratio to the 18cm spacing of the microporous pipes). The branch microporous tubes can be fixed in PVC slots pre-embedded in the bottom of the pool, 3-5 cm from the bottom surface. During aeration, oxygen enters the main pipeline from the oxygen storage tank 3 via a proportional regulating valve and is released through the aeration holes on the surface of the branch microporous tubes, with bubble diameters of approximately 0.5-1.0 mm. In testing, particle image velocimetry (PIV) was used to detect the flow field within the pool. The results showed that the spiral layout could reduce the standard deviation of dissolved oxygen concentration to below 0.2 mg / L. The drum-type microfilter 5 can be equipped with a double-layer stainless steel filter screen, with an inner layer of 200 mesh and an outer layer of 300 mesh. The drum speed is adjustable from 2 to 5 r / min. The fluidized bed biofilter 6 can use porous ceramic ball carriers with a diameter of 10-15 mm and a filling rate of 60%-70%. The UV-ozone composite sterilizer 8 can integrate a 30W UV lamp and an ozone generator, with an ozone dosage set to 0.1-0.3 mg / L. The Venturi oxygenation branch pipe 7 can be connected to the vertical pipe section between the microfilter and the biofilter, with an inlet diameter of 25 mm, a throat diameter of 8 mm, and an installation height of 40-50 cm from the bottom of the tank. The opening of the pneumatic diaphragm regulating valve can be linked to the signal of the distributed oxygen sensor. When the dissolved oxygen concentration in the pool is lower than the set value of 10 mg / L, the opening of the regulating valve increases linearly to 40%-60%. Experimental data shows that the Venturi branch pipe can increase the dissolved oxygen concentration of the return water by 2-3 mg / L and reduce the load on the main aeration system by 15%-20%. Technical effects: Continuous oxygen supply is achieved through parallel molecular sieve adsorption tower 2 and dual-path switching valve; the spiral aeration pipe layout improves the uniformity of dissolved oxygen distribution; and the Venturi branch pipe compensates for oxygen loss in the circulating water. System operational stability is improved, the dissolved oxygen concentration in fish fry rearing pond 4 is maintained at 10±0.5mg / L, water circulation treatment energy consumption is reduced by 20%, and the equipment maintenance cycle is extended to more than 3 months.

[0015] In another technical solution, the cultivation pool 4 unit of this utility model is formed by splicing modified PP plates to form a compound circular pool group with a diameter gradient. The diameter of a single pool is 1.4-1.6 meters and is matched with the spacing of the branch microporous tubes in a 1:10 ratio. The slope of the pool bottom is adjusted to 8±1° and a spiral guide channel is set with a channel depth of 2-3mm. The roughness of the inner wall of the pool is Ra1.2±0.2μm and the surface is coated with a titanium dioxide photocatalytic coating.

[0016] Culture tank 4 can be made of modified PP material, with 2%-3% by mass of anti-algae masterbatch added as a modifier. The material thickness can be set to 8-10mm. The duplex circular tank group can be designed with a gradient combination of diameters of 1.4m, 1.5m, and 1.6m, with a uniform tank height of 0.8m. The tank bottom slope can be adjusted to three levels: 7°, 8°, and 9°. The ratio of tank diameter to the spacing of the branch microporous tubes can be controlled at 1:9, 1:10, and 1:11. The tanks can be joined using hot-melt welding, with a weld width controlled at 3-5mm. The tank groups can be arranged linearly along the water flow direction, with a 0.5m spacing between adjacent tanks. During assembly, the central drain outlet at the bottom of the pool can be located at the lowest point of the slope, and the overflow weir on the side wall of the pool can be equipped with a height-adjustable screw, with an adjustment range covering 70%-80% of the total height of the pool. During operation, the water flows towards the center along an 8° slope, and the spiral guide channel guides the water flow to form a vortex, reducing sediment accumulation at the bottom of the pool. Testing used a staining tracer method to observe the water flow trajectory, and the results showed that the guide channel can increase the water flow velocity by 15%-20%. The spiral guide channel can be machined into a single-threaded structure. The channel depth can be set to 2.0mm, 2.5mm, or 3.0mm, and the channel width can be designed to be 5-8mm. The starting end of the guide channel can be 20cm away from the pool wall, and the ending end extends to the edge of the central drain outlet. The surface roughness Ra value of the inner wall of the pool can be controlled at three levels: 1.0μm, 1.2μm, and 1.4μm, using sandblasting. The sandblasting medium can be alumina particles with a particle size of 80-100 mesh. The titanium dioxide photocatalytic coating can be a mixture of nano-titanium dioxide powder and epoxy resin. The coating thickness can be set to 20-30μm. After curing, the photocatalytic performance is activated by ultraviolet light irradiation. The diversion channels can be arranged clockwise along the slope of the pool bottom, with the center line of the channel 15-20cm from the edge of the pool bottom. The coating can be applied in two stages: the first primer is applied using a roller coating process, with a thickness of 10-15μm; the second topcoat is applied using a spray coating process, with a thickness of 10-15μm. In the experiment, the pool was placed in an environment with a light intensity of 5000lx for 72 hours. Compared to the uncoated pool, the amount of algae attached was reduced by 60%-70%. The tank structure strength test can be performed by applying hydrostatic pressure up to 1.2 times the design water depth (0.96 meters) for 24 hours, and no leakage was found in the welds. The flow guiding efficiency of the guide channel can be evaluated through a particle tracking experiment; after releasing 1000 tracer particles, more than 95% of the particles entered the discharge outlet within 10 minutes. The antibacterial properties of the titanium dioxide coating meet the GB / T 21866-2008 standard, with an inhibition rate of over 99% against Escherichia coli. Technical Benefits: The use of a gradient-diameter duplex pool design with matched aeration pipe layout optimizes hydrodynamic characteristics and reduces dissolved oxygen distribution variations. Spiral guide channels enhance the shear force of the water flow at the pool bottom, reducing the probability of organic matter deposition. A titanium dioxide coating inhibits algae growth, while a Ra 1.2μm rough surface promotes dissolved oxygen diffusion. The pool structure's stability meets the requirements of high-density aquaculture, extending water quality maintenance cycles by 30%-40%. In another technical solution, the filter screen of the roller microfilter 5 of this utility model has a double-layer gradient mesh structure, with an inner layer of 200 mesh and an outer layer of 300 mesh. The packing material of the fluidized bed biofilter 6 adopts a graphene-based porous ceramic carrier, which increases the specific surface area to 1000-1500m² / m³ and loads nitrifying bacteria microcapsules in the pores.

[0017] The drum-type microfilter 5 can use a double-layer stainless steel filter screen. The inner layer mesh size can be set to 180, 200, or 220 mesh, and the outer layer mesh size can be set to 280, 300, or 320 mesh. The filter screen thickness can be controlled to 0.3mm for the inner layer and 0.2mm for the outer layer, and the filter screen gap can be adjusted to 0.05-0.1mm. The drum diameter can be designed to be 400mm, and the rotation speed can be set to three levels: 2r / min, 3r / min, and 4r / min. The drive motor power can be selected as 0.75kW. During assembly, the inner filter screen can be welded to the inside of the drum frame, while the outer filter screen is fixed to the outer surface of the drum with clips. The drum axis can be installed horizontally inside the microfiltration unit housing, with the inlet located directly above the drum, at a vertical distance of 30-40cm from the drain pipe at the bottom of the tank. During operation, water containing impurities enters the drum through the inlet. The inner filter screen traps particles larger than 75μm, while the outer filter screen further filters suspended solids larger than 50μm. During testing, suspended particles with a diameter range of 20-100μm were introduced into the water, and the total retention rate of the dual-layer filter screen reached 92%-95%. Graphene-based porous ceramic supports can be made of alumina matrix doped with 1%-2% graphene powder. The support diameter can be set to 8mm, 10mm, or 12mm, and the porosity can be controlled at 60%-70%. The specific surface area can be achieved by adjusting the sintering temperature (1100℃-1300℃) to achieve a gradient distribution of 800-1500m² / m³. Nitrifying bacteria microcapsules can be made of sodium alginate-chitosan composite wall material, with concentrated nitrifying bacteria solution (bacterial density ≥10^8 CFU / mL) as the core material. The microcapsule particle size can be controlled at 200-300μm. The filler can be filled in the vertical reaction column of the fluidized bed biofilter 6, and the filling height is 60%-70% of the total height of the column body. An aeration disc can be installed at the bottom of the reaction column, the gas-water ratio is set to 3:1, and the upward flow velocity of water flow is controlled at 20-30 cm / min. In the experiment, the filler is immersed in simulated wastewater with an ammonia nitrogen concentration of 5 mg / L, the ammonia nitrogen removal rate reaches 90%-95% after 24 hours, and the activity of nitrifying bacteria on the surface of the filler remains stable. The filter screen blockage test can be run continuously for 72 hours, and the change in pressure difference between the inlet and outlet is recorded. A pressure difference rise rate lower than 0.01 MPa / h is considered qualified. In the impact load resistance test of the filler, wastewater with an ammonia nitrogen concentration of 15 mg / L is instantaneously added to the fluidized bed biofilter 6, and the detected effluent ammonia nitrogen concentration is stable below 1.5 mg / L after 6 hours of continuous operation. The slow-release performance of microcapsules can be evaluated by measuring the concentration of free bacteria in water, and the fluctuation range of bacteria concentration is less than ±10% within a 30-day operation cycle. Technical effect: the double-layer gradient filter screen intercepts suspended particles in a graded manner, which reduces the load on a single-layer filter screen and prolongs the cleaning cycle of the filter screen. The graphene-based ceramic carrier increases the specific surface area and enhances the adhesion capacity of biofilms, and the nitrifying bacteria microcapsules realize directional release of the bacterial flora and maintain their activity. The removal efficiency of ammonia nitrogen and nitrite by the system is significantly improved, and the water turbidity is stable below 5 NTU for a long term.

[0018] In another technical solution, the end of the branched microporous tube can also be connected to a backwash branch. The backwash branch is respectively connected to the high-pressure water source and the outlet of the oxygen storage tank 3 through a quick-connect three-way valve, and the flow direction of the backwash water is arranged opposite to the aeration direction. A drain valve and an oxygen valve are arranged on the main pipeline; wherein, when oxygen is supplied through the branched microporous tube, the oxygen valve is opened and the drain valve is closed; when the branched microporous tube is backwashed, the oxygen valve is closed and the drain valve is opened. The high-pressure water source can be provided by a centrifugal pump, and the output pressure is set to 0.3-0.4 MPa. The quick-connect three-way valve can be integrated with an electromagnetic driving mechanism, and the switching time does not exceed 2 seconds, and the flow direction of the backwash water is 180° opposite to the aeration direction. The end of the branched microporous tube can be connected with a quick-connect interface made of ABS material, the backwash pipeline can be arranged along the outer side of the pool wall, and the interface is 15-20 cm away from the pool wall. During the test, pulse flushing is performed with 0.4 MPa high-pressure water, each flush lasts for 30 seconds, with an interval of 2 hours. After flushing, the aeration holes are observed through a microscope, and the blockage rate decreases from 35% before flushing to below 5%. During the backwash process, the outlet pressure fluctuation range of the oxygen storage tank 3 is controlled within ±0.05 MPa, and no gas leakage occurs. In another technical solution, the quick-connect three-way valve of the backwash branch of the present utility model integrates a pressure self-locking mechanism, and a cyclonic pulse generator is arranged at the connection end of the high-pressure water source.

[0019] The quick-connect three-way valve can be equipped with a brass electromagnetically driven valve body, and the valve core can have a built-in spring-type pressure self-locking mechanism with three adjustable locking thresholds: 0.3MPa, 0.4MPa, and 0.5MPa. A pressure sensor can be integrated into the valve body inlet to monitor pipeline pressure fluctuations in real time within ±0.02MPa. The valve body diameter can match standard DN15 pipes, and the interface thread can be G1 / 2 specification. During assembly, the quick-connect three-way valve can be installed at the connection between the backwash branch and the high-pressure water source, 30-50cm from the end of the branch microporous tube. During operation, when the backwash pressure exceeds 0.4MPa, the self-locking mechanism automatically cuts off the water supply; the valve resets when the pressure drops below 0.3MPa. In testing, a 0.6MPa instantaneous pressure shock was applied to the pipeline, and the self-locking response time was less than 0.5 seconds, with no structural damage occurring. The vortex pulse generator can utilize a stainless steel vortex structure, with an internal flow channel diameter of 8mm, a maximum of 6 vortex vanes, and a tilt angle of 45°. The pulse frequency can be controlled by adjusting the inlet water pressure; when the water source pressure is 0.4-0.6MPa, the output pulse frequency is available in three levels: 5Hz, 6Hz, and 7Hz. The generator outlet can be connected to an ABS reducing fitting to extend the water flow diameter from 8mm to 12mm. The pulse generator can be installed in the horizontal pipe section between the high-pressure water pump outlet and the quick-connect three-way valve, 20-30 cm from the three-way valve inlet. During operation, the water flow generates periodic vortices through the vortex structure, forming a pulsed water flow with pressure fluctuations of ±0.05 MPa. In the experiment, a microporous tube contaminated with calcifications was placed in the rinsing station. After 5 minutes of pulse rinsing, microscopic observation showed that the removal rate of deposits on the tube wall reached over 90%. The backwash water flow direction can be adjusted to three reverse angles: 130°, 135°, and 140°. Pipe bends can be achieved using PVC 45°+90° combination connectors. The end interface of the branch microporous pipe can be designed with a tapered flare structure at a 60° flare angle, maintaining a distance of 5-8cm from the flushing nozzle. The backwash pipeline can be laid vertically along the outer side of the pool wall, with fixed supports spaced 50-80cm apart. During testing, a 135° counter-current flushing angle was used, with high-pressure water injected in the opposite direction from the end of the branch microporous tube, creating shear force against the aeration direction. Particle imaging velocimetry (PIV) observations showed that the counter-current water flow generated turbulent eddies with an intensity of 15%-20% at the tube wall, which is 3-5 times higher than the traditional co-current flushing mode. After flushing, the aeration hole permeability increased from 65% to over 95%. Technical benefits: The pressure-locking mechanism prevents overpressure damage to the microporous structure, the swirling pulsed water flow enhances the efficiency of removing deposits from the pipe wall, and the 135° reverse flushing angle optimizes fluid shearing. Backwashing operations are safer, micropore clogging rates are significantly reduced, aeration uniformity is maintained for over 120 days, and system operational stability is effectively guaranteed.

[0020] In another technical solution, a conical diffusion one-way valve is provided at the connection between the backwash branch and the branch microporous tube of this utility model, and the valve core surface is covered with a hydrophobic silicon carbide coating.

[0021] The conical diffuser check valve can be made with a brass body, and the cone angle can be designed to be 15°, 20°, or 25°. The diffuser length can be set to 30mm, 35mm, or 40mm. The valve core can be equipped with a stainless steel spring, and the valve opening pressure differential threshold can be adjusted to 0.1MPa, 0.15MPa, or 0.2MPa. The valve seat sealing surface can be machined to a mirror finish with Ra0.4μm, and the valve core stroke can be controlled to 5-8mm. During assembly, the check valve can be vertically installed at the connection between the backwash branch and the branch microporous tube. The valve body inlet is connected to the high-pressure water source pipeline via a flange, and the outlet is fixed to the end of the branch microporous tube via a clamp. During operation, when the backwash water pressure reaches 0.15 MPa, the valve core overcomes the spring resistance and opens, allowing the water flow to diffuse along the conical flow channel, with the flow velocity decreasing from 3 m / s to 1.2 m / s. In testing, when a back pressure of 0.5 MPa was applied to the valve body, the leakage was less than 0.1 L / min. The silicon carbide coating can be made from silicon carbide powder with a particle size of 1-5 μm, deposited on the valve core surface using a plasma spraying process. The coating thickness can be controlled at 20 μm, 25 μm, or 30 μm. The coating porosity can be set to 10%-15%, and the contact angle can be increased to three levels: 125°, 130°, and 135°. Before spraying, the valve core surface can be sandblasted, with the roughness Ra value controlled at 1.6-3.2 μm. During the coating process, the valve core can be fixed on a rotating fixture, the spraying distance is maintained at 100-150mm, and the argon protective gas flow rate is set to 30-40L / min. In the experiment, the coated valve core was immersed in a saturated solution containing CaCO3 for 72 hours, and the scale area on the surface was reduced by 70%-80% compared with the uncoated valve core. In the one-way valve flow capacity test, under a pressure difference of 0.15 MPa, the water flow rate can reach 12-15 m³ / h, and the flow resistance coefficient is less than 0.5. The coating wear resistance can be tested by a friction testing machine; after 10,000 cycles under a pressure of 50 N, the coating thickness loss is less than 5 μm. In the sealing performance test, the valve body is held at a pressure of 0.6 MPa for 10 minutes, and the pressure drop does not exceed 0.02 MPa. Technical Benefits: The conical diffuser flow channel reduces water flow impact noise and optimizes backwash pressure distribution. The hydrophobic silicon carbide coating reduces scale and corrosion on the valve core, extending valve lifespan. Improved one-way valve sealing performance virtually eliminates water backflow during backwashing, enhancing system reliability. In another technical solution, the nano-ceramic coating on the outer wall of the branched microporous tube of this invention is embedded with silver ion slow-release particles with a particle size of 2-5μm, and the pores of the coating are filled with pH-responsive hydrogel.

[0022] The nano-ceramic coating can be made from alumina-zirconia composite ceramic powder with a particle size range of 50-100 nm, and the coating thickness can be set to three levels: 50 μm, 60 μm, and 70 μm. The silver ion slow-release particles can be made from silver-loaded zeolite microparticles with a silver content controlled at 2%-3% (mass fraction), and the particle size can be screened to three gradients: 2.0 μm, 3.0 μm, and 5.0 μm. The coating porosity can be controlled from 35% to 45% by adjusting the sintering temperature (800℃-1000℃), and the pore size can be controlled to 5 μm, 8 μm, and 10 μm. The coating can be applied to the outer wall of the branched microporous tube using plasma spraying. The spraying distance can be set to 100-150 mm, and the substrate preheating temperature should be maintained at 200-250℃. During operation, silver ions are slowly released into the water through the pores, maintaining a release rate of 0.05-0.1 mg / L / day. In experiments, the coated pipe fittings were immersed in water containing E. coli (10^5 CFU / mL), and the antibacterial rate exceeded 99% after 72 hours. pH-responsive hydrogels can be made from acrylic acid-acrylamide copolymers, with swelling ratios set to 1:1.5, 1:1.8, and 1:2.0, and a response pH threshold of 6.5-8.5. The concentration of the hydrogel precursor solution can be controlled at 10%-15%. After injection into the pores, polymerization is initiated by ultraviolet light (wavelength 365nm), and the curing time is set to 10-15 minutes. The effective pore size after filling can be adjusted to 2-4 μm, with a dynamic response time of less than 30 seconds. The hydrogel can be filled into the coating pores using a vacuum negative pressure infusion process, with the infusion pressure set between -0.05 MPa and -0.08 MPa. When the pH of the water is below 7.0, the hydrogel shrinks, increasing the pore size and aeration rate by 10%-15%; when the pH is above 8.0, the hydrogel swells, decreasing the pore size and inhibiting excessive oxygen loss. In the test, when the pH cyclically varied within the range of 6.0-9.0, the fluctuation range of the aeration flux was less than ±5%. The coating's abrasion resistance can be evaluated through a sand impact test. After 30 days of continuous operation in water with a flow rate of 2 m / s and a sand content of 100 mg / L, the coating thickness loss was less than 5 μm. The silver ion release rate can be detected by atomic absorption spectrometry, with a standard deviation of release concentration of less than ±0.02 mg / L over a 30-day period. The hydrogel's pH response performance can be verified by swelling ratio measurement, which remained stable at 1:1.8±0.1 at pH 7.5. Technical benefits: Silver ion slow-release particles continuously inhibit microbial film formation, reducing the risk of bioclogging in aeration holes. The pH-responsive hydrogel dynamically adjusts pore flux based on water pH, adapting aeration efficiency to the metabolic needs of fish fry. The mechanical strength and corrosion resistance of the nano-ceramic coating ensure long-term stable operation of the microporous tubes, significantly reducing system maintenance costs. In another technical solution, the distributed oxygen sensor array of this utility model adopts an optical fiber dissolved oxygen probe group. The probes are distributed along the spiral branch microporous tube in accordance with the golden ratio, with a spacing of 25±2cm. The probe shell is equipped with a self-cleaning brush ring.

[0023] The fiber optic dissolved oxygen probe can utilize a fluorescence quenching principle sensor. The probe diameter can be set to 8mm, 10mm, or 12mm, and the measurement range can cover 0-20mg / L. The golden ratio distribution can be arranged at a spacing of 0.618 times the total length of the spiral branched microporous tube, with specific spacing options of 23cm, 25cm, and 27cm. The probe mounting bracket can be made of 316 stainless steel, and its height can be adjusted to 5cm, 7cm, or 10cm. The probes can be installed along the spiral branched microporous tube. The first probe is 25cm from the beginning of the branched microporous tube, and subsequent probes are arranged at intervals of 25cm ± 2cm. During assembly, the probe sensing end can be vertically inserted into the water, maintaining a depth of 15-20cm below the water surface. During operation, the probe collects dissolved oxygen data every 30 seconds and transmits it to the control module via fiber optic signal. In the test, dissolved oxygen standard solution was added at different locations in the tank, and the deviation between the probe detection value and the standard value was less than ±0.15mg / L. The self-cleaning brush ring can be made of silicone rubber, with bristle hardness adjustable to three levels: Shore A60, A65, and A70. Bristle lengths can be controlled to 8mm, 10mm, and 12mm. The inner diameter of the brush ring can match the probe housing diameter, and the gap can be adjusted from 0.5 to 1.0mm. The drive motor can be a micro stepper motor, with speed settings of 5r / min, 8r / min, and 10r / min. The cleaning program is scheduled to start twice daily, each time lasting 30 seconds. The brush ring can be fitted into the middle of the probe housing and moves up and down reciprocatingly via a sliding rail structure, with a stroke range set to 3-5 cm. During cleaning, the contact pressure between the brush bristles and the probe surface is maintained at 0.1-0.3 N to avoid damaging the optical window. In the experiment, the probe was placed in water containing suspended solids (50 mg / L) and operated continuously for 30 days. After cleaning with the brush ring, the light transmittance attenuation rate of the optical window was less than 5%. The rationality of the probe distribution can be verified through computational fluid dynamics (CFD) simulation. A golden ratio distribution in a spiral flow field can achieve dissolved oxygen sampling coverage of over 98%. In the brush ring cleaning efficiency test, a simulated biofilm (200 μm thick) was applied to the probe surface; the residual thickness after cleaning was less than 20 μm. The stability of the fiber optic signal can be detected using an optical power meter; during 30 days of continuous operation, the standard deviation of signal fluctuation was less than ±0.5%. Technical benefits: By arranging the probes according to the golden ratio, the system accurately captures changes in dissolved oxygen gradients within the spiral flow field, eliminating detection blind spots. A self-cleaning brush ring automatically removes deposits from the probe surface, maintaining the stability of the optical detection window's transmittance. The system can provide real-time feedback on dissolved oxygen distribution within the pool, offering high-precision data support for oxygen supply regulation, with overall detection errors controlled within ±0.2 mg / L.

[0024] Although the embodiments of this utility model have been disclosed above, they are not limited to the applications listed in the specification and embodiments. They can be applied to various fields suitable for this utility model. For those skilled in the art, other modifications can be easily made. Therefore, without departing from the general concept defined by the claims and their equivalents, this utility model is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A pure oxygen supply system for the cultivation of specialty freshwater fish fry, characterized in that, It includes an oxygen generator unit, a microporous aeration device, a cultivation tank unit, and a circulating water treatment unit; The oxygen generator unit includes two sets of molecular sieve adsorption towers, an air compressor, and an oxygen storage tank with pressure feedback, all arranged in parallel. The outlet of the air compressor is connected to the inlet of the two sets of molecular sieve adsorption towers through a dual-path switching valve. The outlet of the molecular sieve adsorption tower is connected to the oxygen storage tank through a manifold. The outlet of the oxygen storage tank is equipped with a proportional regulating valve that is linked to the dissolved oxygen concentration. The microporous aeration device includes a main pipe and branch microporous pipes. The inlet of the main pipe is connected to the proportional regulating valve of the outlet of the oxygen storage tank. The end of the main pipe extends to the bottom of the cultivation tank unit and connects with 10 spiral branch microporous pipes. The spacing between adjacent branch microporous pipes is 1 / 8 to 1 / 10 of the tank diameter and maintains a spacing of 18±2cm. The surface of the branch microporous pipes has 0.2±0.05mm aeration holes staggered at a 120° angle. The hole spacing is proportional to the branch microporous pipe spacing in a ratio of 1:1.

5. The circulating water treatment unit includes a drum-type microfilter, a fluidized bed biofilter, and an ultraviolet-ozone composite sterilizer arranged in series. The inlet of the microfilter is connected to the center of the bottom of the pool through a siphon drain pipe, and its outlet is connected to the inlet of the sterilizer through the biofilter. The outlet of the sterilizer is connected to the inlet of the cultivation pool through a jet nozzle. The pipeline between the fluidized bed biofilter and the sterilizer is equipped with a Venturi oxygenation branch pipe that connects to the outlet of the oxygen storage tank. This branch pipe is equipped with a pneumatic membrane regulating valve, and the opening degree of the pneumatic membrane regulating valve is linked to the signal of the distributed oxygen sensor installed in the cultivation tank.

2. The pure oxygen supply system according to claim 1, characterized in that, The cultivation pool unit is formed by splicing modified PP sheets to create a complex circular pool group with a gradient in diameter. The diameter of a single pool is 1.4-1.6 meters and is matched with the spacing of the branch microporous tubes in a 1:10 ratio. The slope of the pool bottom is adjusted to 8±1° and a spiral guide channel is set with a channel depth of 2-3 mm. The roughness of the inner wall of the pool is Ra1.2±0.2μm and the surface is coated with a titanium dioxide photocatalytic coating.

3. The pure oxygen supply system according to claim 1, characterized in that, The filter screen of the roller microfilter has a double-layer gradient mesh structure, with an inner layer of 200 mesh and an outer layer of 300 mesh. The packing material of the fluidized bed biofilter uses a graphene-based porous ceramic carrier, which increases the specific surface area to 1000-1500 m² / m³ and loads nitrifying bacteria microcapsules in the pores.

4. The pure oxygen supply system according to claim 1, characterized in that, The branch microporous tube is connected to a backwash branch at its end. The backwash branch is connected to a high-pressure water source and an oxygen storage tank outlet via quick-connect three-way valves. The backwash water flow direction is opposite to the aeration direction. The main pipeline is equipped with a drain valve and an oxygen valve. When oxygen is supplied through the branch microporous tube, the oxygen valve is open and the drain valve is closed. When backwashing the branch microporous tube, the oxygen valve is closed and the drain valve is open.

5. The pure oxygen supply system according to claim 4, characterized in that, The quick-connect three-way valve of the backwash branch integrates a pressure self-locking mechanism, and its high-pressure water source connection end is equipped with a vortex pulse generator.

6. The pure oxygen supply system according to claim 5, characterized in that, A conical diffusion check valve is installed at the connection between the backwash branch and the branch microporous tube, and the valve core surface is covered with a hydrophobic silicon carbide coating.

7. The pure oxygen supply system according to claim 1, characterized in that, The nano-ceramic coating on the outer wall of the branched microporous tube is embedded with silver ion slow-release particles with a particle size of 2-5 μm, and the pores of the coating are filled with pH-responsive hydrogel.

8. The pure oxygen supply system according to claim 1, characterized in that, The array of distributed oxygen sensors uses a fiber optic dissolved oxygen probe group. The probes are distributed along the spiral branch microporous tube in accordance with the golden ratio, with a spacing of 25±2cm. The probe shell is equipped with a self-cleaning brush ring.

Images