Circulating aquaculture system based on multiple sensors and flow control method thereof

Abstract

The invention provides a recirculating aquaculture system based on multiple sensors and a flow control method of the recirculating aquaculture system. Accurate adjustment is achieved through water level difference and turbidity double-signal fusion. The water level difference delta H of the water inlet end and the water outlet end of the microfilter and the aquaculture water turbidity T are collected in real time; after filtering and denoising, comparing delta H with preset threshold values delta H0 and delta H1 (delta H1gt, delta H0), and comparing T with T0 and T1 (T1gt, T0); the control logic is as follows: when delta H is greater than or equal to delta H1 and T is greater than or equal to T1, the circulating pump is accelerated; when delta Hlt; delta H0 and Tlt; when T0 is reached, the circulating pump is decelerated; the system continuously monitors the actual flow, adaptively corrects the adjustment coefficient according to the deviation, and improves the precision; and if the delta H and the T continuously exceed the standard, triggering maintenance alarm. The traditional lag problem is solved through millisecond-level response, the limitation of single signal monitoring is broken through, and flow adjustment is precisely matched with the working condition; invalid loss of equipment is reduced through dynamic self-adaptive adjustment, equipment loss is reduced, and the service life of core components is prolonged; meanwhile, water quality stability is guaranteed, and a suitable growth environment is provided for cultured organisms.

Description

Technical Field

[0001] This invention relates to the field of recirculating aquaculture technology, specifically to a multi-sensor-based recirculating aquaculture system and its flow control method. Background Technology

[0002] Recirculating aquaculture systems (RAS) are one of the core pieces of equipment in modern industrialized aquaculture. They utilize physical, chemical, and biological unit treatment technologies to achieve continuous purification and reuse of aquaculture water. The stability of water quality and the ability to regulate water flow directly affect the health of the cultured organisms and the overall energy consumption level of the system.

[0003] Currently, water flow regulation in recirculating aquaculture systems mainly relies on fixed-frequency pumps or flow regulation based on a single water level difference sensor signal. Existing water flow regulation methods have significant shortcomings and are difficult to adapt to system operation requirements: (1) delayed response: single water level difference feedback cannot promptly capture changes in water quality or fluctuations in filtration status, resulting in a delay in the response to flow adjustment; (2) low regulation accuracy: failing to consider the overall state of the system, such as turbidity and water load, easily leads to inaccurate water flow regulation and deviation from actual needs; (3) high energy consumption: the system cannot adaptively match flow according to different filtration states, causing long-term high-load operation of equipment and significant energy waste. Therefore, it is urgent to research an intelligent flow control method to achieve precise and efficient water flow regulation. Summary of the Invention

[0004] To address the issues of response lag in existing water flow regulation methods in current recirculating aquaculture systems, this invention provides a multi-sensor-based recirculating aquaculture system and its flow control method. This flow control method enables rapid response and stable control of water flow regulation, effectively resolving the response lag problem of traditional control modes, significantly improving the efficiency of aquaculture water treatment and energy saving, while ensuring continuous stability of water quality in the aquaculture environment and guaranteeing the safe and reliable operation of the system.

[0005] The technical solution adopted in this invention is as follows:

[0006] A multi-sensor-based recirculating aquaculture system includes an aquaculture pond unit, a microfiltration unit, a circulating pump unit, a water level difference sensor, a turbidity sensor, a control unit, an electric regulating valve, and a variable frequency pump actuator. The effluent from the aquaculture pond unit is filtered by the microfiltration unit and then returned to the aquaculture pond unit, forming a closed loop. The water level difference sensor is installed at the inlet and outlet of the microfiltration unit to collect the real-time water level difference ΔH before and after filtration. The turbidity sensor is installed in the outlet pipeline of the aquaculture pond unit near the pond outlet, with its probe perpendicular to the water flow direction, to collect the real-time turbidity T of the aquaculture water. The signals from the water level difference sensor and the turbidity sensor are connected to the control unit, which is electrically connected to the electric regulating valve and the variable frequency pump actuator to output control signals.

[0007] Furthermore, the circulating pump unit includes a main variable frequency pump and a standby pump. The control unit can automatically switch the operating status of the main variable frequency pump and the standby pump based on real-time monitoring data of ΔH and T or the operating status of the main variable frequency pump.

[0008] Furthermore, the signal output terminals of the water level difference sensor and the turbidity sensor are both connected to the signal input terminal of the control unit, and the signal output terminal of the control unit is connected to the signal input terminals of the electric regulating valve and the variable frequency pump actuator, respectively.

[0009] Furthermore, the control unit integrates a data acquisition module, a signal processing module, a logic determination module, an execution module, a feedback correction module, and an alarm module, with each module working together to control the system flow.

[0010] Furthermore, the electric regulating valve is one of the following: an electric single-seat regulating valve, an electric sleeve regulating valve, an electric cage regulating valve, an electric angle regulating valve, or an electric regulating butterfly valve.

[0011] On the other hand, the present invention also proposes a flow control method for the above-mentioned multi-sensor-based recirculating aquaculture system, comprising the following steps:

[0012] Step 1: The data acquisition module of the control unit uses a water level difference sensor to collect the water level difference ΔH between the inlet and outlet of the microfiltration unit in real time, and uses a turbidity sensor to collect the water turbidity T of the outlet pipeline of the aquaculture pond unit in real time.

[0013] Step 2: The signal processing module of the control unit sequentially performs filtering and noise reduction preprocessing on the acquired ΔH signal and T signal;

[0014] Step 3: The logic determination module of the control unit compares the ΔH after preprocessing in step 2 with the preset thresholds ΔH0 and ΔH1, and compares the T after preprocessing in step 2 with the preset thresholds T0 and T1, where ΔH1 > ΔH0 and T1 > T0;

[0015] Step 4: The execution module of the control unit outputs a control signal based on the logic judgment result to adjust the speed of the variable frequency pump actuator or the opening of the electric regulating valve to realize the system flow regulation. The specific regulation logic is as follows: when ΔH≥ΔH1 and T≥T1, the circulating pump unit is driven to accelerate; when ΔH<ΔH0 and T<T0, the circulating pump unit is driven to decelerate.

[0016] Step 5: The feedback correction module of the control unit continuously monitors the actual flow rate change of the system, and adaptively corrects the flow rate adjustment ratio coefficient K based on the deviation value ΔQ between the actual flow rate and the target flow rate to optimize the flow rate adjustment accuracy;

[0017] Step 6: When ΔH continuously exceeds ΔH1 and T continuously exceeds T1, the alarm module of the control unit outputs a maintenance alarm signal.

[0018] Furthermore, the preset thresholds ΔH0, ΔH1, T0, and T1 in step 3 are manually input via the local operation panel.

[0019] Furthermore, the preset thresholds ΔH0, ΔH1, T0, and T1 are determined by the following method: based on the species of aquaculture, the stocking density, or recent historical data, a fixed threshold is preset.

[0020] Furthermore, in step 4, when ΔH0≤ΔH<ΔH1 and T0≤T<T1, the execution module maintains the current variable frequency pump speed and the electric regulating valve opening unchanged.

[0021] Furthermore, in step 4, when ΔH ≥ ΔH1 and T < T0, or ΔH < ΔH0 and T ≥ T1, the execution module fine-tunes the flow rate according to the proportion of the current flow rate.

[0022] Compared with the prior art, the advantages of this invention are:

[0023] The flow control method for a recirculating aquaculture system based on multiple sensors provided by this invention monitors the water level difference of the microfilter and the turbidity of the aquaculture water in real time. Employing dual-signal fusion control logic, it overcomes the problem of traditional regulation lag with millisecond-level judgment, achieving zero-delay flow response and significantly improving response speed. The dual sensors collaboratively perceive the overall operating status of the system, breaking through the limitations of single-signal monitoring. This ensures both rapid response and stable controllability of water flow regulation, while also enabling precise matching of flow regulation to actual operating conditions, significantly optimizing regulation accuracy. Simultaneously, it can dynamically and adaptively adjust the flow rate based on water quality, reducing ineffective equipment operation losses and achieving superior energy efficiency (energy savings of 15%–25%). It also effectively avoids equipment damage caused by excessive flushing and high-frequency start-stop cycles, extending the service life of core components and ensuring safe and reliable system operation. Furthermore, it significantly improves the treatment efficiency of the aquaculture water, continuously ensuring stable and balanced water quality, creating a suitable growth environment for aquaculture organisms, and achieving precise and controllable water quality. Attached Figure Description

[0024] Figure 1 A structural diagram of a multi-sensor-based recirculating aquaculture system provided by the present invention;

[0025] Figure 2 This is a flowchart illustrating the implementation of a flow control method for a multi-sensor-based recirculating aquaculture system provided by the present invention. Detailed Implementation

[0026] To better understand the present invention, it will be further described below with reference to specific embodiments and accompanying drawings. Those skilled in the art should understand that the following embodiments are illustrative of the invention and should not be construed as limiting the invention in any way. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention. The scope of protection of the present invention is defined by the claims.

[0027] It should be noted that when a component is said to be "fixed" to another component, it can be directly attached to the other component or there may be an intervening component. When a component is said to be "connected" to another component, it can be directly connected to the other component or there may be an intervening component. The terms "vertical," "horizontal," "left," "right," "high," "low," and similar expressions used in this document are for illustrative purposes only.

[0028] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0029] Example 1

[0030] The present invention provides a method such as Figure 1 The multi-sensor-based recirculating aquaculture system shown includes an aquaculture pond unit, a microfiltration unit, a circulating pump unit, a water level difference sensor, a turbidity sensor, a control unit, an electric regulating valve, and a variable frequency pump actuator. The effluent from the aquaculture pond unit is filtered by the microfiltration unit and then returned to the aquaculture pond unit, forming a closed loop. The water level difference sensor is installed at both the inlet and outlet of the microfiltration unit to collect the real-time water level difference ΔH before and after filtration. The turbidity sensor is installed in the outlet pipeline of the aquaculture pond unit near the pond outlet, with its probe perpendicular to the water flow direction, to collect the real-time turbidity T of the aquaculture water. The signals from the water level difference sensor and the turbidity sensor are connected to the control unit, which is electrically connected to the electric regulating valve and the variable frequency pump actuator to output control signals.

[0031] The aquaculture pond unit can be circular, oriented, or other shapes, and can be fixed or movable. The aquaculture pond can be a single-layer or multi-layer structure. There can be one or more aquaculture ponds. An oxygenation device can also be installed on one side of the aquaculture pond to increase dissolved oxygen levels. The oxygenation device can be an air pump, aerator, aeration stone, etc. An external water inlet can also be provided on the aquaculture pond, allowing external water to be supplied to the aquaculture pond.

[0032] The circulating pump unit includes a main variable frequency pump and a standby pump. The control unit can automatically switch the operating status of the main variable frequency pump and the standby pump based on real-time monitoring data of ΔH and T or the operating status of the main variable frequency pump.

[0033] The signal output terminals of the water level difference sensor and the turbidity sensor are both connected to the signal input terminal of the control unit. The signal output terminal of the control unit is connected to the signal input terminal of the electric regulating valve and the variable frequency pump actuator, respectively.

[0034] The control unit integrates a data acquisition module, a signal processing module, a logic decision module, an execution module, a feedback correction module, and an alarm module. All modules work together to control the system flow.

[0035] The electric regulating valve is one of the following: electric single-seat regulating valve, electric sleeve regulating valve, electric cage regulating valve, electric angle regulating valve, or electric regulating butterfly valve.

[0036] The embodiments of the present invention also provide a method such as Figure 2 The flow control method for a recirculating aquaculture system based on multiple sensors, as shown, includes the following steps:

[0037] Step 1: The data acquisition module of the control unit uses a water level difference sensor to collect the water level difference ΔH between the inlet and outlet of the microfiltration unit in real time, and uses a turbidity sensor to collect the water turbidity T of the outlet pipeline of the aquaculture pond unit in real time.

[0038] Step 2: The signal processing module of the control unit sequentially performs filtering and noise reduction preprocessing on the acquired ΔH signal and T signal;

[0039] Step 3: The logic determination module of the control unit compares the ΔH after preprocessing in step 2 with the preset thresholds ΔH0 and ΔH1, and compares the T after preprocessing in step 2 with the preset thresholds T0 and T1, where ΔH1 > ΔH0 and T1 > T0;

[0040] Step 4: The execution module of the control unit outputs a control signal based on the logic judgment result to adjust the speed of the variable frequency pump actuator or the opening of the electric regulating valve to realize the system flow regulation. The specific regulation logic is as follows: when ΔH≥ΔH1 and T≥T1, the circulating pump unit is driven to accelerate; when ΔH<ΔH0 and T<T0, the circulating pump unit is driven to decelerate.

[0041] Step 5: The feedback correction module of the control unit continuously monitors the actual flow rate change of the system, and adaptively corrects the flow rate adjustment ratio coefficient K based on the deviation value ΔQ between the actual flow rate and the target flow rate to optimize the flow rate adjustment accuracy;

[0042] Step 6: When ΔH continuously exceeds ΔH1 and T continuously exceeds T1, the alarm module of the control unit outputs a maintenance alarm signal.

[0043] In step 2, the signal processing module uses Kalman filtering, moving average filtering, or median filtering algorithms to denoise the original ΔH and T signals, and supports manual configuration via the control unit or adaptive adjustment based on the signal fluctuation amplitude.

[0044] The preset thresholds ΔH0, ΔH1, T0, and T1 in step 3 are manually entered through the local operation panel. The preset thresholds ΔH0, ΔH1, T0, and T1 are determined in the following way: based on the species of farmed organisms, stocking density, or recent historical data, a fixed threshold is preset.

[0045] In step 4, when ΔH0 ≤ ΔH < ΔH1 and T0 ≤ T < T1, the execution module maintains the current variable frequency pump speed and the electric regulating valve opening unchanged. When ΔH ≥ ΔH1 and T < T0, or ΔH < ΔH0 and T ≥ T1, the execution module fine-tunes the flow rate according to the current flow rate ratio.

[0046] This embodiment incorporates water level sensors at both the inlet and outlet of the microfilter. By acquiring the water level difference before and after filtration, a real-time sensing structure for filtration resistance across the filter screen is constructed. This structure directly characterizes the degree of clogging and filtration load of the microfilter screen. This design avoids the judgment lag problem inherent in existing technologies that infer filtration status indirectly through backwashing frequency or water consumption. It enables the system to respond at the initial stage of filter fouling, effectively improving the timeliness and accuracy of filtration status identification and providing a reliable equipment foundation for the fine-tuning of circulating water flow.

[0047] This embodiment installs a turbidity sensor on the outlet pipe of the aquaculture pond in a recirculating aquaculture system, and uses an in-situ pipe installation method to achieve online real-time detection of turbidity in the aquaculture water. This allows the water pollution load to participate in the recirculating water flow regulation process as a direct control parameter. This device structure breaks through the existing technical approach of relying solely on equipment operation results for control without the need for water quality monitoring devices. It achieves direct intervention of water quality parameters on the actuators, significantly improving the system's response sensitivity and control accuracy to changes in aquaculture load, and contributing to the maintenance of a stable aquaculture water environment.

[0048] This embodiment constructs a multi-sensor collaborative sensing control architecture by simultaneously inputting the microfilter water level difference signal and the water turbidity signal into the control unit. The control unit then links the variable frequency circulating pump actuator and the electric regulating valve to achieve coordinated regulation of the circulating water flow. This pump-valve collaborative control structure features short response time and strong regulation continuity, enabling rapid flow adjustment based on real-time changes in the system's operating status. This avoids the regulation lag and insufficient control precision problems caused by single control objects and segmented adjustment methods in existing technologies, thereby improving the stability and energy efficiency of system operation at the equipment level.

[0049] Therefore, the flow control method of the recirculating aquaculture system based on multi-sensor in this embodiment can accurately adjust the water circulation volume in the recirculating aquaculture system according to the different water quality conditions of the aquaculture water body. This ensures the stable operation of the recirculating aquaculture system while maximizing the adjustment speed, shortening the adjustment cycle, saving water resources, and reducing energy consumption.

[0050] The multi-sensor-based recirculating aquaculture system of this embodiment was placed in a facility-based recirculating aquaculture base for use, and some operational data were obtained after running the system for 30 days using the method of this embodiment.

[0051] date Ammonia nitrogen concentration (mg / L) Nitrite concentration (mg / L) October 13 0.2 0.067 October 14 0.1 0.035 October 15 0.1 0.042 October 16 0.2 0.075 October 17 0.2 0.071 October 18 0.1 0.047 October 19 0.2 0.056 October 20 0.2 0.050 October 21 0.3 0.087 October 22 0.4 0.095 October 23 0.3 0.079 October 24 0.4 0.093 October 25 0.4 0.097 October 26 0.3 0.081 October 27 0.3 0.074 October 28 0.3 0.072 October 29 0.2 0.069 October 30 0.2 0.071 October 31 0.4 0.086 November 1 0.3 0.074 November 2 0.3 0.079 November 3 0.4 0.091 November 4 0.3 0.080 November 5 0.4 0.095 November 6 0.3 0.084 November 7 0.3 0.078 November 8 0.2 0.073 November 9 0.2 0.066 November 10 0.3 0.072 November 11 0.3 0.077

[0052] In this embodiment, the water quality indicators (ammonia nitrogen and nitrite) of the recirculating water obtained by the multi-sensor-based recirculating aquaculture system and its flow control method are stable at below 0.4 mg / L and 0.1 mg / L, respectively, meeting the requirements of high-density aquaculture. Moreover, during 30 days of continuous operation, the system showed no significant fluctuations or abnormalities, verifying the reliability and efficiency of the multi-sensor-based recirculating aquaculture system and its flow control method of the present invention.

[0053] Although the embodiments of the present invention have been described above in conjunction with specific examples, it should be noted that these described embodiments are merely some specific implementations of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, various modifications and improvements can be made without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A multi-sensor based recirculating aquaculture system, characterized in that, The application relates to an aquaculture system, which comprises a culture pond unit, a microfilter unit, a circulating pump unit, a water level difference sensor, a turbidity sensor, a control unit, an electric regulating valve and a variable frequency pump actuator; water from the culture pond unit is filtered by the microfilter unit and then flows back to the culture pond unit, forming a closed circulation loop; the water level difference sensor is arranged at the water inlet end and the water outlet end of the microfilter unit respectively and is used for collecting the water level height difference Delta H before and after microfilter filtration in real time; the turbidity sensor is installed on the water outlet pipeline of the culture pond unit and is arranged vertically to the water flow direction in the pipeline, and is used for collecting the turbidity T of the culture water in real time; the signals of the water level difference sensor and the turbidity sensor are connected to the control unit, and the control unit is electrically connected with the electric regulating valve and the variable frequency pump actuator to output control signals.

2. A multi-sensor based recirculating aquaculture system as claimed in claim 1, wherein, The circulating pump unit comprises a main variable frequency pump and a standby pump, and the control unit can automatically switch the running states of the main variable frequency pump and the standby pump according to the real-time monitoring data of Delta H and T or the running state of the main variable frequency pump.

3. A multi-sensor based recirculating aquaculture system as claimed in claim 1, wherein, The signal output ends of the water level difference sensor and the turbidity sensor are connected with the signal input end of the control unit, and the signal output end of the control unit is connected with the signal input ends of the electric regulating valve and the variable frequency pump actuator.

4. A multi-sensor based recirculating aquaculture system as claimed in claim 1, wherein, The control unit integrates a data acquisition module, a signal processing module, a logic judgment module, an execution module, a feedback correction module and an alarm module, and the modules jointly control the system flow.

5. A multi-sensor based recirculating aquaculture system as claimed in claim 1, wherein, The electric regulating valve is one of an electric single-seat regulating valve, an electric sleeve regulating valve, an electric cage regulating valve, an electric angle regulating valve and an electric regulating butterfly valve.

6. A flow control method applied to the multi-sensor based recirculating aquaculture system according to any one of claims 1 to 5, characterized in that, The application further discloses an aquaculture system control method, which comprises the following steps: Step 1: the data acquisition module of the control unit collects the water level height difference Delta H of the water inlet end and the water outlet end of the microfilter unit by using the water level difference sensor and collects the turbidity T of the water in the water outlet pipeline of the culture pond unit by using the turbidity sensor; Step 2: the collected Delta H signal and T signal are sequentially subjected to filtering and denoising pretreatment by the signal processing module of the control unit; Step 3: the logic judgment module of the control unit compares the pretreated Delta H with preset threshold values Delta H0 and Delta H1 and compares the pretreated T with preset threshold values T0 and T1, wherein Delta H1>Delta H0 and T1>T0; Step 4: the execution module of the control unit outputs control signals according to the logic judgment result, adjusts the rotating speed of the variable frequency pump actuator or the opening degree of the electric regulating valve, and realizes system flow adjustment, and the specific adjustment logic is that when Delta H is greater than or equal to Delta H1 and T is greater than or equal to T1, the circulating pump unit is driven to accelerate running; and when Delta H is less than Delta H0 and T is less than T0, the circulating pump unit is driven to decelerate running; Step 5: the feedback correction module of the control unit continuously monitors the actual flow variation of the system, adaptively corrects the flow regulation proportion coefficient K according to the deviation value Delta Q of the actual flow and the target flow, and optimizes the flow regulation precision; Step 6: when Delta H continuously exceeds Delta H1 and T continuously exceeds T1, the alarm module of the control unit outputs a maintenance alarm signal.

7. The multi-sensor based flow control method of a recirculating aquaculture system according to claim 6, wherein, The preset threshold values Delta H0, Delta H1, T0 and T1 in step 3 are manually input by a local operation panel.

8. The multi-sensor based flow control method of a recirculating aquaculture system according to claim 7, wherein, The preset threshold values AH0, AH1, T0, T1 are determined by presetting fixed threshold values based on the species of the cultured organisms, the culture density, or recent historical data.

9. The multi-sensor based flow control method of a recirculating aquaculture system according to claim 6, wherein, In step 4, when AH0≤AH<AH1 and T0≤T<T1, the executing module maintains the current variable frequency pump rotating speed and electric regulating valve opening unchanged.

10. The multi-sensor based flow control method of a recirculating aquaculture system according to claim 6, wherein, In step 4, when AH≥AH1 and T<T0, or AH<AH0 and T≥T1, the executing module adjusts the flow rate in proportion to the current flow rate.

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