Circulating aquaculture system and flow control method thereof

Abstract

The invention relates to the field of aquatic feed, in particular to a recirculating aquaculture system and a flow control method thereof. The invention discloses a flow control method of a recirculating aquaculture system. The flow control method comprises the following steps: collecting liquid level data of a clear water bin in a microfilter, and judging whether the liquid level data of the clear water bin in unit time exceeds a set threshold value or not so as to determine whether a control system starts a backwashing pump to carry out backwashing on the microfilter or not. And collecting the backwashing times of the backwashing pump in unit time and judging whether the backwashing times exceed a set threshold value II or not. And collecting the water consumption of the backwashing pump during backwashing in unit time, and judging whether the water consumption exceeds a set threshold value III or not. Whether the circulation amount of water in the circulating water culture system needs to be regulated or not is judged according to the number of times of backwashing and the water consumption. By means of the flow control method, the circulation amount of water in the circulating water aquaculture system can be accurately and rapidly adjusted, the response speed of the whole adjusting process is high, and the adjusting result does not have hysteresis.

Description

Technical Field

[0001] The present invention relates to the technical field of circulating aquaculture, and in particular to a circulating aquaculture system and a flow control method thereof. Background Art

[0002] Recirculating aquaculture is a method of aquaculture that uses artificially controlled water treatment equipment to remove or transform pollutants such as organic matter, inorganic matter and nitrides in aquaculture water, thereby achieving circulating aquaculture of water bodies. The biggest feature of this aquaculture method is that it can maintain optimal biological growth conditions in the aquaculture pond under high-density aquaculture conditions, thereby shortening the aquaculture time, improving aquaculture efficiency and reducing energy consumption. In recirculating aquaculture, microfiltration is a commonly used solid-liquid separation equipment. It generally intercepts particulate matter (such as fish feces, bait, etc.) in the aquaculture water through a microporous filter, thereby reducing the load of the subsequent nitrification tank and improving the water quality treatment efficiency. Therefore, the good or bad operation of the microfiltration machine is one of the key factors directly related to whether the entire recirculating aquaculture system can operate stably.

[0003] The microfilter in the prior art is generally operated and cleaned according to a set program. Since the amount of feed and the growth rate of fish in the breeding process are dynamically changing, the content of ammonia nitrogen and nitrite in the entire breeding water body is also changing in real time. In order to ensure that the circulating aquaculture system can be carried out stably in the prior art, it is necessary to adjust the circulation volume of water in the circulating aquaculture system according to the real-time situation of water quality. The specific adjustment method is as follows: first, the water quality needs to be monitored continuously, and then professional personnel are required to adjust the various parameters of the circulating aquaculture system according to the monitored data to achieve the purpose of adjusting the circulation volume of water in the circulating aquaculture system. The above-mentioned adjustment method requires that water quality detection equipment be equipped at each stage of the circulating aquaculture system, and professional personnel are also required to operate it. This existing operation mode not only increases the operating cost of the entire circulating aquaculture system, but also makes the adjustment method by manually making judgments based on monitoring data, which makes the response speed of the entire circulating aquaculture system slow, and the adjustment result has hysteresis, which is not conducive to the stable operation of the circulating aquaculture system. Summary of the invention

[0004] In order to solve the technical problems that the existing recirculating aquaculture system has a slow response speed when adjusting the circulation volume of water in the system, the adjustment result has a lag, and is not conducive to the stable operation of the recirculating aquaculture system, the present invention provides a recirculating aquaculture system and a flow control method thereof.

[0005] The present invention is implemented by the following technical solution: a flow control method for a circulating aquaculture system, which comprises the following steps:

[0006] Collecting the liquid level data of the clean water tank in the microfiltration machine, and transmitting the collected data to the control system, the control system is used to receive the liquid level data of the clean water tank in a unit time and determine whether the liquid level data of the clean water tank in a unit time exceeds a set threshold value one;

[0007] When the liquid level data of the clean water tank exceeds the set threshold value 1, the control system is used to start the backwashing pump to backwash the microfilter;

[0008] The backwashing times of the backwashing pump are collected, and the collected data are transmitted to the control system, wherein the control system is used to receive the backwashing times of the backwashing pump in a unit time and determine whether the backwashing times of the backwashing pump in a unit time exceeds a set threshold value 2;

[0009] The water consumption of the backwashing pump during backwashing is collected, and the collected data is transmitted to the control system, wherein the control system is used to receive the water consumption of the backwashing pump per unit time and determine whether the water consumption of the backwashing pump per unit time exceeds a set threshold value three;

[0010] When the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value 2 or the water consumption of the backwashing pump exceeds the set threshold value 3, the control system increases the operating flow rate of the circulation pump by adjusting the control valve on the circulation pump, and the circulation pump is used to control the flow rate of water in the circulating aquaculture system;

[0011] When the backwashing times of the backwashing pump per unit time is lower than the set threshold value one and the water consumption of the backwashing pump is lower than the set threshold value two, the control system does not need to adjust the control valve on the circulation pump, and the circulation pump maintains a constant flow rate set by the control system.

[0012] As a further improvement of the present invention, the control system can also collect the feeding time of the recirculating aquaculture system and determine whether the collected feeding time is within the set threshold value four; when the feeding time is within the set threshold value four and the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value two or the water consumption of the backwashing pump exceeds the set threshold value three, the control system controls the feeding device to reduce the feeding amount and at this time the circulating pump runs at a constant speed according to the flow rate set by the control system; when the feeding time exceeds the set threshold value four and the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value two or the water consumption of the backwashing pump exceeds the set threshold value three, the control system is used to increase the operating flow rate of the circulating pump.

[0013] As a further improvement of the present invention, the increased speed of the circulation pump is divided into three gears, including a first gear speed-up speed, a second gear speed-up speed and a third gear speed-up speed, wherein the minimum value of the first gear speed-up speed is higher than the flow rate of water in the circulating aquaculture system set by the control system; the minimum value of the second gear speed-up speed is higher than the maximum value of the first gear speed-up speed and the maximum value of the second gear speed-up speed is lower than the minimum value of the third gear speed-up speed;

[0014] When the backwashing times of the backwashing pump are higher than the set threshold value 2 and the water consumption of the backwashing pump is lower than the set threshold value 3, the control system controls the circulation pump to directly speed up to the first speed-up speed through the control valve;

[0015] When the backwashing times of the backwashing pump are higher than the set threshold value 2 and the water consumption of the backwashing pump is higher than the set threshold value 3, the control system controls the circulation pump to directly speed up to the second gear speed-up speed through the control valve;

[0016] When the backwashing times of the backwashing pump are lower than the set threshold value 2 and the water consumption of the backwashing pump is higher than the set threshold value 2, the control system controls the circulation pump to directly speed up to the third gear speed-up speed through the control valve.

[0017] As a further improvement of the present invention, the threshold value four of the feeding time is 30 minutes of feeding.

[0018] The present invention also includes a circulating water aquaculture system, which includes a breeding pond, a microfilter, a nitrification tank, an automatic sewage discharge device, a circulation pump and a control system; the breeding pond is used for breeding aquatic animals, the microfilter is arranged between the breeding pond and the nitrification tank, the circulation pump is used to transport the breeding water in the breeding pond to the microfilter and transport the water filtered by the microfilter to the nitrification tank, the nitrification tank is used to nitrify the water filtered by the microfilter and transport the nitrified water back to the breeding pond through the circulation pump, and the control system is used to control the operating flow rate of the circulation pump.

[0019] As a further improvement of the present invention, the microfilter includes a microfilter body, a clean water tank, a backwash pump and a backwash nozzle. The microfilter body is used to filter the aquaculture water entering the aquaculture pond. The microfilter body and the clean water tank are independently arranged. The backwash pump is used to transport the water in the clean water tank to the backwash nozzle, and the backwash nozzle is used to clean the microfilter body.

[0020] As a further improvement of the present invention, a liquid level sensor is provided in the clean water tank, and the liquid level sensor is used to monitor the liquid level of the clean water tank and transmit the monitored data to the control system in real time. The control system is used to start the backwash pump when the data monitored by the liquid level sensor exceeds the threshold value set by the control system, and the backwash pump is able to backwash the microfiltration machine body through the backwash nozzle.

[0021] As a further improvement of the present invention, a flow meter is further provided in the water supply pipe of the backwash pump, and the flow meter is used to measure the water consumption of the backwash pump and transmit the measured data to the control system; a sensor is further provided on the backwash pump, and the sensor is used to record the number of backwashing times of the backwash pump and transmit the recorded data to the control system; the control system adjusts the operating flow rate of the circulation pump by comparing the received water consumption of the backwash pump with the threshold value three set by the control system and by comparing the number of backwashing times of the backwash pump with the threshold value two set by the control system;

[0022] When the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value 2 or the water consumption of the backwashing pump exceeds the set threshold value 3, the control system increases the operating flow rate of the circulation pump through the control valve, and the circulation pump is used to control the flow rate of water in the circulating aquaculture system;

[0023] When the backwashing times of the backwashing pump per unit time is lower than the set threshold value 2 and the water consumption of the backwashing pump is lower than the set threshold value 3, the control system does not need to adjust the operating flow rate of the circulation pump. At this time, the circulation pump maintains a constant speed operation at the set flow rate.

[0024] As a further improvement of the present invention, the circulation pump is a variable speed pump.

[0025] The technical solution provided by the present invention has the following beneficial effects:

[0026] (1) The flow control method of the circulating aquaculture system of the present invention determines the specific conditions of the aquaculture water body through the data of three parameters: the liquid level of the water in the clean water tank, the number of backwashing times of the backwashing pump per unit time, and the water consumption of the backwashing pump per unit time. And through the flow control method of the circulating aquaculture system of the present invention, the control system can compare the data of the above three parameters received with the parameters set by the control system, and automatically control the control valve of the circulating pump according to the comparison result, so as to achieve the purpose of real-time adjustment of the flow rate of the water in the circulating aquaculture system, thereby adjusting the circulation amount of water in the circulating aquaculture system. The whole adjustment process is simple and rapid, with a fast response speed, and the adjustment result has no hysteresis, while the adjustment method in the prior art has a slow response speed and a hysteresis in the adjustment result, which will cause the circulation amount of water in the circulating aquaculture system after adjustment to be mismatched with the real-time water quality of the aquaculture water body to be treated, thereby easily causing the circulation of the circulating aquaculture system to fail. Therefore, the flow regulation method of the recirculating aquaculture system in the present invention can effectively solve the technical problems in the prior art of manually judging the data detected by the water quality detection equipment and adjusting the water flow rate according to the judgment result, such as slow response speed and lag in the adjustment result, which is not conducive to the stable operation of the recirculating aquaculture system.

[0027] (2) The flow control method of the circulating aquaculture system of the present invention does not need to set up a lot of water quality monitoring equipment, thereby reducing the floor space of the entire circulating aquaculture system, and also reducing the production cost and operation cost of the entire circulating aquaculture system. Moreover, this automatic control method does not need to invest a lot of manpower and material resources, which can further reduce the operation cost of the circulating aquaculture system. At the same time, this method can automatically adjust the circulation volume of water in the circulating aquaculture system according to the backwashing condition of the microfilter, thereby ensuring that the water quality of the aquaculture water body can be stably treated by the circulating aquaculture system while avoiding excessive or insufficient replacement of the circulating water, thereby ensuring that the circulating aquaculture system can operate stably while avoiding the waste of water resources.

[0028] (3) The flow control method of the recirculating aquaculture system of the present invention can accurately adjust the circulation volume of water in the recirculating aquaculture system according to the different water quality conditions of the aquaculture water body, thereby ensuring the stable operation of the recirculating aquaculture system while maximizing the adjustment speed, shortening the adjustment cycle, and saving water resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a structural diagram of a circulating aquaculture system provided by the present invention.

[0030] Figure 2 The present invention provides a flow chart of the implementation of a flow control method for a circulating aquaculture system. DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form a new embodiment.

[0032] In the description of the present invention, it should be noted that for directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicating directions and positional relationships are based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and cannot be understood as limiting the specific protection scope of the present invention. The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "including" and "having" in the specification and claims of the present invention and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device including a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0033] This embodiment provides a circulating aquaculture system. Figure 1 ,pass Figure 1 It can be seen that the water in the circulating water aquaculture system is flowing. The circulating water aquaculture system includes a breeding pond, a microfilter, a nitrification tank, an automatic sewage discharge device, a circulating pump and a control system. The control system is used to control the overall operation of the entire circulating water aquaculture system. The breeding pond is used to breed aquatic animals. The microfilter is set between the breeding pond and the nitrification tank. The microfilter is used to filter the breeding water entering the breeding pond. The circulating pump is used to transport the breeding water in the breeding pond to the microfilter and to transport the water filtered by the microfilter to the nitrification tank. The nitrification tank is used to nitrify the water filtered by the microfilter and transport the nitrified water back to the breeding pond through the circulating pump. The control system controls the running flow rate of the circulating pump through the control valve. The circulating pump can circulate the breeding water between the breeding pond, the microfilter and the nitrification tank to improve the utilization rate of water resources. The control system is used to control the flow rate of water in the circulating water aquaculture system through the circulating pump.

[0034] The breeding pond can be circular, directional or other shapes, and it can be fixed or movable. The breeding pond can be a single-layer structure or a multi-layer structure. The number of breeding ponds can be one or more. One side of the breeding pond can also be provided with an oxygen aeration device, and the oxygen aeration device is used to increase dissolved oxygen in the breeding pond. The oxygen aeration device can be an air pump, an aerator, an aeration stone, etc. The breeding pond can also be provided with an external water interface, and external water can be transported to the breeding pond through the external water interface.

[0035] The control system may be a PLC controller.

[0036] The control system can also be equipped with multiple alarm mechanisms. When the liquid level monitored by the liquid level sensor exceeds 1000mm or is less than 200mm, the system triggers an audible and visual alarm. When the backwash pump works continuously for more than 15 minutes or the water consumption exceeds 300L, the system automatically shuts down and sends an alarm signal. The system is also equipped with a manual reset function to ensure that abnormal situations are handled in a timely manner.

[0037] The circulation pump can be composed of multiple conventional variable frequency water pumps in parallel. Each conventional variable frequency water pump can control one place independently. For example, a conventional variable frequency water pump can be installed between the breeding pond and the microfiltration machine, a variable frequency water pump can be installed between the microfiltration machine and the nitrification tank, and a conventional variable frequency water pump can be installed between the nitrification tank and the breeding pond. These conventional variable frequency water pumps can well control the water flow rate in the entire circulating water breeding system.

[0038] The microfilter is a device used to filter the aquaculture water. It can remove pollutants such as suspended matter, colloids, bacteria, etc. in the aquaculture water and improve the transparency and cleanliness of the water. The microfilter can be a pressure type, vacuum type or other type of filter. The microfilter includes a microfilter body, a clean water tank, a backwash pump and a backwash nozzle. The microfilter body is used to filter the aquaculture water entering the aquaculture pond. A filter membrane and a filter cavity are provided in the microfilter body. The filter membrane is a medium used to filter and separate the aquaculture water. It can be a membrane made of ceramic, polymer or other materials. The filter cavity is a space for accommodating the filter membrane and the aquaculture water body. It can be cylindrical, square box or other shapes. The clean water tank is set in the microfilter. The backwash pump is used to transport the water in the clean water tank to the backwash nozzle. The backwash nozzle is used to clean the microfilter body. The backwash pump and the backwash nozzle can remove the dirt and blockages attached to the surface of the filter membrane, thereby restoring the permeability and filtration efficiency of the filter membrane. The backwash pump is a pump used to provide backwashing pressure and flow. It can be a centrifugal pump, a plunger pump or other types of pumps. The backwash pump is also provided with a valve for controlling the backwash flow and time, and the valve can be a solenoid valve or an electric valve. Backwash pipes are provided between the backwash pump and the backwash nozzle, and between the backwash pump and the clean water tank, and the backwash pipes can be metal pipes or plastic pipes.

[0039] The microfilter may also include an automatic sewage discharge device, which is used to discharge the dirt intercepted by the microfilter after filtering and the impurities after the backwash pump flushes the filter screen of the microfilter to the outside of the microfilter.

[0040] The automatic sewage discharge device can be controlled by the control system. It is understandable that when the circulating aquaculture system needs to increase the water circulation volume, the control system can simultaneously open the automatic sewage discharge device, which can discharge the impurities remaining after filtering in the microfilter, thereby ensuring that the microfilter can operate stably.

[0041] Specifically, the automatic sewage discharge device can be started under the following conditions: the liquid level in the clean water tank exceeds 850mm, or the backwash pump continuously works for more than 10 minutes. The automatic sewage discharge device runs for 5-8 minutes each time, and the operating cycle is 12 hours. It is understood that the specific operating time of the automatic sewage discharge device can also be automatically adjusted by the control system according to the actual water quality.

[0042] In recirculating aquaculture, the microfilter is a commonly used solid-liquid separation device, which intercepts particulate matter (such as fish feces, bait, etc.) in the aquaculture water through the filter screen of the microfilter body, thereby reducing the load of the subsequent nitrification tank and improving the water quality treatment efficiency. Then, as the particulate matter accumulates on the filter screen, the amount of filtered water of the microfilter body will gradually decrease, causing the liquid level in the clean water tank to rise, which will affect the normal operation of the microfilter. Therefore, in order to solve this problem in the prior art, a backwashing device is equipped on the microfilter, and the water in the clean water tank is reversely flushed into the filter screen through the backwashing nozzle by a backwashing pump to flush high-pressure water into the filter screen, so as to wash off the particulate matter on the filter screen, thereby restoring the water flow of the microfilter to ensure that the microfilter can operate stably.

[0043] A liquid level sensor is provided in the clean water tank, which is used to monitor the liquid level in the clean water tank and transmit the monitored data to the control system in real time. The control system is used to start the backwash pump when the data monitored by the liquid level sensor exceeds the threshold set by the control system. The backwash pump can backwash the microfiltration machine body through the backwash nozzle.

[0044] The monitoring range of the liquid level sensor in the clean water tank is 0-1000mm. When the liquid level in the clean water tank reaches 750-850mm (threshold 1), the control system starts the backwash pump to backwash the microfilter; when the liquid level in the clean water tank is lower than 600mm, the backwash pump is stopped to resume normal operation.

[0045] A flow meter is also provided in the water supply pipe of the backwash pump, which is used to measure the water consumption of the backwash pump and transmit the measured data to the control system. A sensor is also provided on the backwash pump, which is used to record the number of backwashing times of the backwash pump and transmit the recorded data to the control system. The control system adjusts the operating flow rate of the circulation pump by comparing the received water consumption of the backwash pump with the threshold value three set by the control system and by comparing the number of backwashing times of the backwash pump with the threshold value two set by the control system.

[0046] When the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value two or the water consumption of the backwashing pump exceeds the set threshold value three, the control system increases the operating flow rate of the circulation pump through the control valve. The circulation pump is used to control the flow rate of water in the circulating aquaculture system.

[0047] When the backwashing times of the backwashing pump per unit time are lower than the set threshold value 2 and the water consumption of the backwashing pump is lower than the set threshold value 3, the control system does not need to adjust the operating flow rate of the circulation pump. At this time, the circulation pump maintains a constant speed operation at the set flow rate.

[0048] It is understandable that when the control system compares the number of backwashing times of the backwashing pump per unit time with the threshold value 2 set by the control system and the water consumption of the backwashing pump per unit time with the threshold value 3 set by the control system, the control system may first compare the number of backwashing times of the backwashing pump per unit time with the threshold value 2 set by the control system, and then compare the water consumption of the backwashing pump per unit time with the threshold value 3 set by the control system. It is also possible to first compare the water consumption of the backwashing pump per unit time with the threshold value 3 set by the control system, and then compare the number of backwashing times of the backwashing pump per unit time with the threshold value 2 of the control coefficient. It is also possible to simultaneously compare the number of backwashing times of the backwashing pump per unit time with the threshold value 2 set by the control system and the water consumption of the backwashing pump per unit time with the threshold value 3 set by the control system. Only when the comparison result of "whether the number of backwashing times of the backwashing pump per unit time exceeds the threshold value 2 set by the control system" is "no" and the comparison result of "whether the water consumption of the backwashing pump per unit time exceeds the threshold value 3 set by the control system" is also "no", and both conditions are met, the control system will not adjust the flow rate of the circulation pump, so that the entire circulating aquaculture system will maintain the flow rate set by the control system for operation.

[0049] Among them, the specific values ​​of threshold 1, threshold 2 and threshold 3 can be set through the control system according to actual breeding needs.

[0050] A flow control method for a circulating aquaculture system, please refer to Figure 2 , Figure 2 The flow chart of one of the implementation steps of the flow control method of the circulation aquaculture system includes the following steps:

[0051] The liquid level data of the clean water tank in the microfiltration machine is collected by the liquid level sensor, and the liquid level data of the clean water tank collected by the liquid level sensor is transmitted to the control system, and the control system is used to receive the liquid level data of the clean water tank per unit time and determine whether the liquid level data of the clean water tank per unit time exceeds a set threshold value one;

[0052] When the liquid level data of the clean water tank exceeds the set threshold value of 1, the control system is used to start the backwash pump to backwash the microfilter body. When the liquid level data of the clean water tank received by the control system does not exceed the set threshold value of 1, it means that the water flow of the microfilter meets the requirements at this time, so the control system does not need to start the backwash pump to clean the microfilter body.

[0053] When the backwash pump backwashes the microfilter body, the sensor collects the backwash times of the backwash pump and transmits the collected data to the control system. The control system is used to receive the backwash times of the backwash pump per unit time and determine whether the backwash times of the backwash pump per unit time exceeds the set threshold value two.

[0054] The water consumption of the backwash pump during backwashing is collected, and the collected data is transmitted to the control system, which is used to receive the water consumption of the backwash pump per unit time and determine whether the water consumption of the backwash pump per unit time exceeds a set threshold value three.

[0055] When the backwashing times of the backwashing pump per unit time are lower than the set threshold value 2 and the water consumption of the backwashing pump is lower than the set threshold value 3, the control system does not need to adjust the control valve on the circulation pump, and the circulation pump maintains a constant flow rate set by the control system.

[0056] When the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value two or the water consumption of the backwashing pump exceeds the set threshold value three, the control system increases the operating flow rate of the circulating pump by adjusting the control valve on the circulating pump. The circulating pump is used to control the flow rate of water in the circulating aquaculture system.

[0057] It can be understood that the flow control method of this embodiment can set the flow rate of water in the circulating aquaculture system to be relatively low while ensuring the normal operation of the circulating aquaculture system. The low flow rate of water mentioned here is relative to the flow rate of water in the circulating aquaculture system mentioned in the background technology. The reason is that the flow control method of the circulating aquaculture system of this embodiment can judge the situation in the microfilter in real time through three parameters. First: the liquid level of water in the clean water tank. Regarding the liquid level of water in the clean water tank, under normal conditions of the water flow of the microfilter, the liquid level of the clean water tank will not be very high. As particles accumulate on the microfilter body, when they accumulate to a certain amount (i.e., the microfilter body is blocked), the water flow of the microfilter body will gradually decrease, thereby causing the liquid level in the clean water tank to rise. At this time, it means that the filtering effect of the microfilter body is relatively poor. If the microfilter is not cleaned in time, it will affect the normal operation of the entire circulating aquaculture system. Therefore, in the flow control method of this embodiment, it is first necessary to judge the filtering condition of the microfilter body by the liquid level in the clean water tank, so as to determine whether the microfilter body needs to be backwashed to ensure the normal operation of the microfilter. Second: the number of backwashing times of the backwashing pump per unit time. The number of backwashing times of the backwashing pump per unit time can reflect the concentration of particulate matter in the aquaculture water body. If the number of backwashing times per unit time is higher, the concentration of particulate matter in the aquaculture water body is also higher. Third: the water consumption of the backwashing pump per unit time. The water consumption of the backwashing pump per unit time can reflect the concentration of harmful substances dissolved in the aquaculture water body. If the water consumption of the backwashing pump per unit time is greater, it means that the concentration of harmful substances dissolved in the aquaculture water body is high.

[0058] Therefore, in the circulating aquaculture system of the present embodiment, the specific conditions of the aquaculture water body can be directly determined by the data of the three parameters: the liquid level of the water in the clean water tank, the number of backwashing times of the backwashing pump per unit time, and the water consumption of the backwashing pump per unit time. And through the flow control method of the circulating aquaculture system in the present invention, the control system can compare the data of the above three parameters received with the parameters set by the control system, and automatically control the control valve of the circulating pump through the comparison result, so as to achieve the purpose of real-time adjustment of the flow rate of the water in the circulating aquaculture system, thereby adjusting the circulation amount of water in the circulating aquaculture system. The whole adjustment process is simple and rapid, with a fast response speed, and the adjustment result has no hysteresis, while the adjustment method in the prior art has a slow response speed and a hysteresis in the adjustment result, which will cause the circulation amount of water in the regulated circulating aquaculture system to be mismatched with the real-time water quality of the aquaculture water body to be treated, thereby easily causing the circulation of the circulating aquaculture system to fail. Therefore, the flow regulation method of the recirculating aquaculture system in the present invention can effectively solve the technical problems in the prior art of manually judging the data detected by the water quality detection equipment and adjusting the water flow rate according to the judgment result, such as slow response speed and lag in the adjustment result, which is not conducive to the stable operation of the recirculating aquaculture system.

[0059] In addition, when the flow control method of the circulating aquaculture system of the present invention is used for operation, in the initial stage, we can set the value of the circulating amount of water in the circulating aquaculture system to the minimum value of the circulating amount of water while being able to maintain the stable operation of the circulating aquaculture system. This setting enables the circulating aquaculture system to save water resources. At the same time, because the present invention uses the backwashing times of the backwashing pump and the water consumption of the backwashing pump to feedback the water quality of the circulating aquaculture system, when the control system receives feedback, it can immediately increase the circulating amount of water in the circulating aquaculture system through the control valve to meet the situation when the aquaculture water body is in poor water quality. Through the above operation, the entire circulating aquaculture system can save water resources while also being able to perform rapid dynamic adjustments according to the actual water quality.

[0060] In addition, through the flow control method of the circulating aquaculture system of the present invention, it is not necessary to set up a lot of water quality monitoring equipment, thereby reducing the floor space of the entire circulating aquaculture system, and also reducing the production cost and operation cost of the entire circulating aquaculture system. Moreover, this automatic control method does not require a large amount of manpower and material resources, and can further reduce the operation cost of the circulating aquaculture system. At the same time, the method can automatically adjust the circulation volume of water in the circulating aquaculture system through the backwashing of the microfilter, thereby ensuring that the water quality of the aquaculture water body can be stably treated by the circulating aquaculture system while avoiding excessive or insufficient replacement of the circulating water, achieving the stable operation of the circulating aquaculture system while avoiding the waste of water resources.

[0061] The circulating aquaculture system of this embodiment can also judge the water quality of the aquaculture water body by the backwashing times of the backwashing pump per unit time and the water consumption of the backwashing pump per unit time. The specific judgment results are as follows:

[0062] When the backwashing times of the backwashing pump per unit time are lower than the threshold value 2 set by the control system and the water consumption of the backwashing pump is also lower than the threshold value 3 set by the control system, the aquaculture water in the circulating aquaculture system is in a relatively responsive state, and the entire circulating aquaculture system can operate according to the set water circulation volume.

[0063] When the backwashing times of the backwashing pump per unit time is higher than the threshold value 2 set by the control system and the water consumption of the backwashing pump is also higher than the threshold value 3 set by the control system, the aquaculture water in the circulating aquaculture system is in a polluted state, and the control system needs to be used to control the control valve of the circulating pump to increase the circulation volume of water in the circulating aquaculture system.

[0064] When the backwashing times of the backwashing pump per unit time is higher than the threshold value 2 set by the control system and the water consumption of the backwashing pump is lower than the threshold value 3 set by the control system, the aquaculture water in the circulating aquaculture system is in a state of high concentration of particulate matter and low concentration of harmful substances dissolved in the water. At this time, it is also necessary to control the control valve of the circulating pump through the control system to increase the circulation volume of water in the circulating aquaculture system.

[0065] When the backwashing times of the backwashing pump per unit time is lower than the threshold value two set by the control system and the water consumption of the backwashing pump is higher than the threshold value three set by the control system, the aquaculture water in the circulating aquaculture system is in a state of low concentration of particulate matter and low concentration of harmful substances dissolved in the water. At this time, it is also necessary to control the control valve of the circulating pump through the control system to increase the circulation volume of water in the circulating aquaculture system.

[0066] In this embodiment, the backwashing number of the backwashing pump can be set to 4-8 times / hour, and the water consumption of the backwashing pump can be set with reference to Table 1. When the backwashing number per unit time exceeds 8 times or the water consumption exceeds the upper limit of the third threshold, the control system increases the flow rate of the circulation pump; when the backwashing number is less than 4 times and the water consumption is less than the lower limit of the third threshold, the circulation pump flows at a constant speed.

[0067] Table 1 shows the range of threshold value 3 for microfilters with different mesh sizes.

[0068] 150 mesh filter specification microfilter 30L / h<Threshold 3<40L / h 170 mesh filter specification microfilter 40L / h<Threshold 3<55L / h 200 mesh filter specification microfilter 60L / h<Threshold 3<80L / h 250 mesh filter specification microfilter 120L / h<Threshold 3<165L / h 325 mesh filter specification microfilter 190L / h<Threshold 3<250L / h

[0069] In view of the above situation where the circulation volume of water in the circulating aquaculture system needs to be increased, the flow control method of the circulating aquaculture system of this embodiment has also been improved as follows: the speed of the circulating pump in the circulating aquaculture system is divided into three gears, specifically including a first gear speed-up speed, a second gear speed-up speed and a third gear speed-up speed. The minimum value of the first gear speed-up speed is higher than the flow rate of water in the circulating aquaculture system set by the control system. The minimum value of the second gear speed-up speed is higher than the maximum value of the first gear speed-up speed and the maximum value of the second gear speed-up speed is lower than the minimum value of the third gear speed-up speed.

[0070] The three speed-up speeds correspond to the above three situations where the water circulation volume in the circulating aquaculture system needs to be increased. The details are as follows:

[0071] When the backwashing times of the backwashing pump are higher than the set threshold value 2 and the water consumption of the backwashing pump is lower than the set threshold value 3, the control system controls the circulation pump to directly speed up to the first gear speed-up speed through the control valve.

[0072] When the backwashing times of the backwashing pump are higher than the set threshold value 2 and the water consumption of the backwashing pump is higher than the set threshold value 3, the control system controls the circulation pump to directly speed up to the second gear speed-up speed through the control valve.

[0073] When the backwashing times of the backwashing pump are lower than the set threshold value 2 and the water consumption of the backwashing pump is higher than the set threshold value 2, the control system controls the circulation pump to directly speed up to the third gear speed-up speed through the control valve.

[0074] In this embodiment, the first gear speed-up speed can be 1.2-1.5 times of the basic flow rate, the second gear speed-up speed can be 1.5-2 times of the basic flow rate, and the third gear speed-up speed can be 2-2.5 times of the basic flow rate. When the corresponding conditions are met, the control system switches the circulation pump flow rate to the corresponding gear by adjusting the control valve.

[0075] Therefore, the flow control method of the recirculating aquaculture system in this embodiment can accurately adjust the circulation volume of water in the recirculating aquaculture system according to the different water quality conditions of the aquaculture water body, thereby ensuring the stable operation of the recirculating aquaculture system while maximizing the adjustment speed, shortening the adjustment cycle, and saving water resources.

[0076] In addition, when designing the flow control method of the recirculating aquaculture system, the applicant also took into account the situation that feeding feed will affect the water quality. Therefore, when the recirculating aquaculture system is actually operating, the control system can also collect the feeding time of the recirculating aquaculture system and determine whether the collected feeding time is within the set threshold value four. Among them, threshold value four can generally be a feeding time of 25-35 minutes, which can generally be set to 30 minutes. In the actual breeding process, fish generally eat within 30 minutes after feeding, so threshold value four is set to 30 minutes. It can be understood that in actual application, the data of threshold value four can be adjusted according to the specific situation of breeding.

[0077] For this embodiment, when the feeding time is within the set threshold value 4, it means that the circulating aquaculture system is in the feeding stage. When the feeding time exceeds the set threshold value 4, it means that 30 minutes have passed since the feeding, and the fish have almost finished eating.

[0078] When the feeding time is within the set threshold value four and the backwashing times of the backwashing pump per unit time exceeds the set threshold value two or the water consumption of the backwashing pump exceeds the set threshold value three, the control system controls the feeding device to reduce the feeding amount and at this time the circulating pump runs at a constant speed according to the flow rate set by the control system.

[0079] When the feeding time exceeds the set threshold value 4 and the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value 2 or the water consumption of the backwashing pump exceeds the set threshold value 3, the control system is used to increase the running flow rate of the circulation pump. Through the above control, the water quality of the aquaculture water body can be adjusted, and the feeding in the aquaculture process can be monitored based on the number of backwashing times of the backwashing pump per unit time and the water consumption of the backwashing pump per unit time to avoid the problem of overfeeding and achieve the purpose of reducing aquaculture costs.

[0080] The recirculating aquaculture system in this embodiment was placed in a facility-based recirculating water base for use, and some operating data were obtained after running the system for 35 days using the method of this embodiment.

[0081]

[0082]

[0083] Among them, through the circulating water aquaculture system and flow control method of this embodiment, the water quality indicators (ammonia nitrogen, nitrite) of the circulating water obtained by operation are all stable at 0.5mg / L and 0.2mg / L or less, meeting the needs of high-density aquaculture. And in 35 days of continuous operation, the system has no obvious fluctuations or abnormalities, verifying the reliability and efficiency of the circulating water aquaculture system and flow control method of the present invention.

[0084] The above describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions only describe the principles of the present invention. The present invention may be subject to various changes and improvements without departing from the spirit and scope of the present invention. These changes and improvements fall within the scope of the present invention to be protected. The scope of protection claimed by the present invention is defined by the attached claims and their equivalents.

Claims

1. A flow control method for a circulating aquaculture system, characterized in that: It includes the following steps: Collecting the liquid level data of the clean water tank in the microfiltration machine, and transmitting the collected data to the control system, the control system is used to receive the liquid level data of the clean water tank in a unit time and determine whether the liquid level data of the clean water tank in a unit time exceeds a set threshold value one; When the liquid level data of the clean water tank exceeds the set threshold value 1, the control system is used to start the backwashing pump to backwash the microfilter; The backwashing times of the backwashing pump are collected, and the collected data are transmitted to the control system, wherein the control system is used to receive the backwashing times of the backwashing pump in a unit time and determine whether the backwashing times of the backwashing pump in a unit time exceeds a set threshold value 2; The water consumption of the backwashing pump during backwashing is collected, and the collected data is transmitted to the control system, wherein the control system is used to receive the water consumption of the backwashing pump per unit time and determine whether the water consumption of the backwashing pump per unit time exceeds a set threshold value three; When the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value 2 or the water consumption of the backwashing pump exceeds the set threshold value 3, the control system increases the operating flow rate of the circulation pump by adjusting the control valve on the circulation pump, and the circulation pump is used to control the flow rate of water in the circulating aquaculture system; When the backwashing times of the backwashing pump per unit time are lower than the set threshold value one and the water consumption of the backwashing pump is lower than the set threshold value two, the control system does not need to adjust the control valve on the circulation pump, and the circulation pump maintains a constant flow rate set by the control system.

2. The flow control method of the circulating aquaculture system according to claim 1, characterized in that: The control system can also collect the feeding time of the circulating aquaculture system and determine whether the collected feeding time is within the set threshold value four; when the feeding time is within the set threshold value four and the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value two or the water consumption of the backwashing pump exceeds the set threshold value three, the control system controls the feeding device to reduce the feeding amount and at this time the circulating pump runs at a constant speed according to the flow rate set by the control system; when the feeding time exceeds the set threshold value four and the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value two or the water consumption of the backwashing pump exceeds the set threshold value three, the control system is used to increase the operating flow rate of the circulating pump.

3. The flow control method of the circulating aquaculture system according to claim 2, characterized in that: The increased speed of the circulating pump is divided into three gears, including a first gear speed-up speed, a second gear speed-up speed and a third gear speed-up speed, wherein the minimum value of the first gear speed-up speed is higher than the flow rate of water in the circulating aquaculture system set by the control system; the minimum value of the second gear speed-up speed is higher than the maximum value of the first gear speed-up speed and the maximum value of the second gear speed-up speed is lower than the minimum value of the third gear speed-up speed; When the backwashing times of the backwashing pump are higher than the set threshold value 2 and the water consumption of the backwashing pump is lower than the set threshold value 3, the control system controls the circulation pump to directly speed up to the first speed-up speed through the control valve; When the backwashing times of the backwashing pump are higher than the set threshold value 2 and the water consumption of the backwashing pump is higher than the set threshold value 3, the control system controls the circulation pump to directly speed up to the second gear speed-up speed through the control valve; When the backwashing times of the backwashing pump are lower than the set threshold value 2 and the water consumption of the backwashing pump is higher than the set threshold value 2, the control system controls the circulation pump to directly speed up to the third gear speed-up speed through the control valve.

4. The flow control method of the circulating aquaculture system according to claim 2, characterized in that: The threshold value 24 of the feeding time is 30 minutes of feeding.

5. A circulating aquaculture system, which is the circulating aquaculture system in the flow control method of the circulating aquaculture system according to any one of claims 1 to 4.

6. The circulating aquaculture system according to claim 5, characterized in that: It includes a breeding pond, a microfilter, a nitrification tank, a circulation pump and a control system; the breeding pond is used for breeding aquatic animals, the microfilter is arranged between the breeding pond and the nitrification tank, the circulation pump is used to transport the breeding water in the breeding pond to the microfilter and transport the water filtered by the microfilter to the nitrification tank, the nitrification tank is used to nitrify the water filtered by the microfilter and transport the nitrified water back to the breeding pond through the circulation pump, and the control system is used to control the flow rate of water in the circulating water breeding system through the circulation pump.

7. The circulating aquaculture system according to claim 6, characterized in that: The microfilter includes a microfilter body, a clean water tank, a backwash pump and a backwash nozzle. The microfilter body is used to filter the aquaculture water entering the aquaculture pond. The clean water tank is arranged in the microfilter. The backwash pump is used to transport the water in the clean water tank to the backwash nozzle. The backwash nozzle is used to clean the microfilter body.

8. The circulating aquaculture system according to claim 7, characterized in that: A liquid level sensor is provided in the clean water tank, and the liquid level sensor is used to monitor the liquid level of the clean water tank and transmit the monitored data to the control system in real time. The control system is used to start the backwash pump when the data monitored by the liquid level sensor exceeds the threshold value set by the control system. The backwash pump can backwash the microfiltration machine body through the backwash nozzle.

9. The circulating aquaculture system according to claim 7, characterized in that: A flow meter is also provided in the water supply pipe of the backwash pump, and the flow meter is used to measure the water consumption of the backwash pump and transmit the measured data to the control system; a sensor is also provided on the backwash pump, and the sensor is used to record the number of backwashing times of the backwash pump and transmit the recorded data to the control system; the control system adjusts the operating flow rate of the circulation pump by comparing the received water consumption of the backwash pump with the threshold value three set by the control system and by comparing the number of backwashing times of the backwash pump with the threshold value two set by the control system; When the number of backwashing times of the backwashing pump per unit time exceeds the set threshold value 2 or the water consumption of the backwashing pump exceeds the set threshold value 3, the control system increases the operating flow rate of the circulation pump through the control valve; When the backwashing times of the backwashing pump per unit time are lower than the set threshold value 2 and the water consumption of the backwashing pump is lower than the set threshold value 3, the control system does not need to adjust the operating flow rate of the circulation pump. At this time, the circulation pump maintains a constant speed operation at the set flow rate.

10. The circulating aquaculture system according to claim 7, characterized in that: The circulating pump is a variable frequency water pump.

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