Aquaculture facility and dissolved oxygen concentration adjustment method

Abstract

An aquaculture facility according to one aspect of the present disclosure comprises: a water tank in which water for aquaculture is stored; an oxygen dissolution device in which oxygen is dissolved in supplied water that is supplied to the water tank; and an aeration device for releasing oxygen into stored water that is stored in the water tank.

Description

Aquaculture equipment and dissolved oxygen concentration adjustment method

[0001] The present disclosure relates to an aquaculture facility and a method for adjusting a dissolved oxygen concentration.

[0002] As a technology related to aquaculture facilities, Patent Document 1 discloses a method for raising fish and shellfish by mechanically dissolving pure oxygen in the same water as the breeding water using an oxygen dissolver, and then injecting this dissolved high-concentration oxygen water into the breeding water. Use of the oxygen dissolver described in Patent Document 1 can improve the breeding efficiency of the aquaculture facilities.

[0003] Japanese Patent Application Publication No. 4-237447

[0004] The dissolved oxygen concentration of the water stored in the tank fluctuates depending on the activity of the aquatic organisms being cultivated, external factors, etc. If the fluctuations in the dissolved oxygen concentration are small, the dissolved oxygen concentration of the stored water can be made to follow the target value by controlling the oxygen dissolution device alone, but if the fluctuations in the dissolved oxygen concentration are large, this may not be possible.

[0005] Therefore, an object of the present disclosure is to provide aquaculture equipment that can respond to changes in the dissolved oxygen concentration of water stored in an aquarium.

[0006] An aquaculture facility according to one embodiment of the present disclosure includes an aquaculture tank for storing water for aquaculture, an oxygen dissolution device for dissolving oxygen inside the supply water supplied to the aquaculture tank, and an aeration device for releasing oxygen into the water stored in the aquaculture tank.

[0007] According to the above configuration, it is possible to provide aquaculture equipment that can respond to changes in the dissolved oxygen concentration of the water stored in the aquarium.

[0008] Fig. 1 is a schematic diagram of the aquaculture facility, Fig. 2 is a flow chart of the control program for the oxygen dissolving device, and Fig. 3 is a flow chart of the control program for the aeration device.

[0009] (Overall Configuration) The aquaculture facility 100 according to an embodiment will be described below. First, the overall configuration of the aquaculture facility 100 will be described. FIG. 1 is a schematic diagram of the aquaculture facility 100. As shown in FIG. 1, the aquaculture facility 100 according to this embodiment includes an aquarium 11, a dissolved oxygen concentration meter 12, an oxygen dissolving device 13, an aeration device 14, and a control device 15. These components will be described in order below.

[0010] <Aquarium> The aquarium 11 is a portion that houses aquatic organisms to be cultivated. In this embodiment, the aquatic organisms are fish. The aquarium 11 may be installed on land or underwater. When the aquarium 11 is installed underwater, it separates the interior from the surrounding water. The aquarium 11 restricts the flow of water between the outside world and the interior water. The material and shape of the aquarium 11 are not limited. For example, the aquarium 11 may be made of plastic or glass. The aquarium 11 may also be made of plate-shaped or sheet-shaped members. The aquarium 11 stores seawater or freshwater depending on the type of aquaculture target. In other words, the water used for aquaculture may be seawater or freshwater. The water for the aquaculture tank 11 may be taken from a water source such as the sea or a river, and all or part of the water in the aquarium 11 may be circulated and reused.

[0011] Water pressurized by a pump (not shown) is continuously supplied to the water tank 11 through a supply line 21, and the water in the water tank 11 is continuously discharged to the outside through a discharge port 22. This allows the aquaculture water stored in the water tank 11 to be continuously replaced. However, the aquaculture water stored in the water tank 11 does not have to be continuously replaced, and may be replaced, for example, at regular intervals. Hereinafter, the water supplied to the water tank 11 will be referred to as "supply water," and the water stored in the water tank 11 will be referred to as "reserved water." In this embodiment, the flow rate of the supply water is constant, but the flow rate of the supply water may be varied.

[0012] <Dissolved oxygen concentration meter> The dissolved oxygen concentration meter 12 is an instrument that measures the dissolved oxygen concentration of the stored water. The dissolved oxygen concentration meter 12 is electrically connected to the control device 15, which will be described later, and a measurement signal from the dissolved oxygen concentration meter 12 is transmitted to the control device 15. The dissolved oxygen concentration of the stored water may fluctuate significantly depending on the activity state of the aquaculture target and external factors.

[0013] <Oxygen Dissolver> The oxygen dissolver 13 is a device that dissolves oxygen in the supply water inside. The oxygen dissolver 13 is located in the supply line 21. An outlet 23 of the supply line 21 is disposed inside the water tank 11. The supply water in which oxygen has been dissolved by the oxygen dissolver 13 is supplied to the water tank 11 via the outlet 23 of the supply line 21. The oxygen dissolver 13 includes an oxygen dissolver main body 26 and an oxygen flow rate adjustment valve 27.

[0014] The oxygen dissolver main body 26 dissolves oxygen in the supply water taken in from the supply line 21 and returns the dissolved oxygen-containing supply water to the supply line 21. The oxygen dissolver main body 26 may, for example, use a screw or other device to push the supply water like a fountain to dissolve oxygen in the supply water, or may supply small bubbles or microbubbles to the supply water, or may pass finely divided supply water through a space of high-pressure oxygen. The oxygen dissolver main body 26 can efficiently produce water with a high dissolved oxygen concentration. The specific configuration of the oxygen dissolver main body 26 is not limited. For example, the oxygen dissolver main body 26 may diffuse the supply water internally to increase its surface area, and then mechanically dissolve oxygen in the supply water by contacting the supply water with oxygen in that state.

[0015] The oxygen flow rate regulating valve 27 is a valve that regulates the amount of oxygen supplied to the oxygen dissolving apparatus main body 26. In other words, by controlling the oxygen flow rate regulating valve 27, the amount of oxygen dissolved in the supply water can be adjusted. Oxygen is supplied from an oxygen supply device 29 to the oxygen dissolving apparatus main body 26 via an oxygen supply line 28. For example, the oxygen supply device 29 may be a PSA (Pressure Swing Adsorption) type oxygen gas generator. The oxygen flow rate regulating valve 27 is located in this oxygen supply line 28.

[0016] <Aeration Device> The aeration device 14 is a device that releases oxygen bubbles into the stored water. The aeration device 14 of this embodiment includes an auxiliary line 31 and an emergency line 32.

[0017] The auxiliary line 31 is a line that directly releases oxygen bubbles into the stored water. The upstream portion of the auxiliary line 31 is connected to the oxygen supply equipment 33, and the downstream portion is located inside the water tank 11. Furthermore, an oxygen auxiliary valve 34 is located on the auxiliary line 31. By opening this oxygen auxiliary valve 34, oxygen supplied from the oxygen supply equipment 33 is transported to the stored water via the auxiliary line 31 and released into the stored water. Note that the oxygen supply equipment 33 that supplies oxygen to the auxiliary line 31 may be the same equipment as the oxygen supply equipment 29 that supplies oxygen to the oxygen dissolving device 13, or may be a different equipment.

[0018] The emergency line 32 is a line that directly releases oxygen into the stored water in an emergency. An example of an emergency is a power outage. However, the emergency is not limited to this and may also be a failure of the oxygen dissolving device 13 or the oxygen supply equipment 29. The upstream portion of the emergency line 32 is connected to an oxygen tank 35, and the downstream portion is located inside the water tank 11. The oxygen tank 35 contains high-pressure oxygen or liquid oxygen. Furthermore, an emergency on-off valve 36 is located on the emergency line 32. The emergency on-off valve 36 is a normally open valve that closes when power is applied. Therefore, in the event of a power outage, the emergency on-off valve 36 opens, and oxygen is transported from the oxygen tank 35 to the stored water via the emergency line 32 and released into the stored water. The emergency on-off valve 36 does not have to be a normally open valve and may be, for example, a control valve that receives power for operation in an emergency.

[0019] The auxiliary line 31 has an auxiliary line nozzle 37 as an outlet. The emergency line 32 has an emergency line nozzle 38 as an outlet. The auxiliary line nozzle 37 and the emergency line nozzle 38 are disposed within the aquarium 11 and release oxygen bubbles into the stored water. The auxiliary line nozzle 37 and the emergency line nozzle 38 are preferably disposed below the aquarium 11. For example, the auxiliary line nozzle 37 and the emergency line nozzle 38 are disposed on the bottom surface of the aquarium 11. Alternatively, the auxiliary line nozzle 37 and the emergency line nozzle 38 may be disposed below the midpoint between the bottom surface of the aquarium 11 and the water surface of the aquarium 11.

[0020] <Control Device> The control device 15 is a device that controls each device provided in the aquaculture facility 100. The control device 15 has a processor, a volatile memory, a nonvolatile memory, an I / O interface, etc. The nonvolatile memory of the control device 15 stores a control program for the oxygen dissolution device 13 and a control program for the aeration device 14, which will be described later, as well as various data, and the processor performs arithmetic processing using the volatile memory based on each program.

[0021] The control device 15 is electrically connected to the dissolved oxygen concentration meter 12 and can obtain the dissolved oxygen concentration of the stored water based on the measurement signal received from the dissolved oxygen concentration meter 12. The control device 15 is also electrically connected to the oxygen flow rate adjustment valve 27 of the oxygen dissolution device 13 and the oxygen auxiliary valve 34 of the aeration device 14 and can control these valves 27, 34 by sending control signals to these valves 27, 34. The control device 15 may be divided into multiple control devices.

[0022] The functions of the elements disclosed herein can be performed using circuits or processing circuits, including general-purpose processors, special-purpose processors, integrated circuits, ASICs (Application Specific Integrated Circuits), conventional circuits, and / or combinations thereof, configured or programmed to perform the disclosed functions. A processor is considered a processing circuit or circuit because it includes transistors and other circuitry. In this disclosure, a circuit, unit, or means is hardware that performs the recited functions or hardware that is programmed to perform the recited functions. The hardware may be hardware disclosed herein or other known hardware that is programmed or configured to perform the recited functions. Where the hardware is a processor, which is considered a type of circuit, the circuit, means, or unit is a combination of hardware and software, and the software is used to configure the hardware and / or processor.

[0023] (Control Program of Oxygen Dissolver) Next, the control program of the oxygen dissolver 13 will be described. Fig. 2 is a flow diagram of the control program of the oxygen dissolver 13. The control program of the oxygen dissolver 13 is a program that controls the oxygen flow rate adjustment valve 27 based on the target value of the dissolved oxygen concentration in the stored water. In other words, it is a program that controls the aperture of the oxygen flow rate adjustment valve 27 so that the dissolved oxygen concentration in the stored water becomes the target value. The control program of the oxygen dissolver 13 is executed by the control device 15.

[0024] When the control program for the oxygen dissolving device 13 is executed, the control device 15 first acquires the dissolved oxygen concentration of the stored water (step S1). As described above, the control device 15 can acquire the dissolved oxygen concentration of the stored water by receiving a measurement signal from the dissolved oxygen concentration meter 12.

[0025] Next, the control device 15 determines whether the dissolved oxygen concentration of the stored water obtained in step S1 is below a predetermined target value (step S2). The target value in this embodiment is a dissolved oxygen concentration of the stored water appropriate for aquaculture. The target value may be a fixed value or a variable value.

[0026] If the controller 15 determines in step S2 that the dissolved oxygen concentration in the stored water is below the target value (NO in step S2), it increases the opening of the oxygen flow rate adjustment valve 27 (step S3). This increases the amount of oxygen contained in the supply water, and the dissolved oxygen concentration in the stored water rises. After step S3, the controller 15 returns to step S1 and repeats each step.

[0027] On the other hand, in step S2, if the control device 15 determines that the dissolved oxygen concentration of the stored water is not below the target value (YES in step S2), the control device 15 proceeds to step S4.

[0028] Subsequently, in step S4, the control device 15 determines whether the dissolved oxygen concentration of the stored water obtained in step S1 is higher than the target concentration.

[0029] If the controller 15 determines in step S4 that the dissolved oxygen concentration in the stored water exceeds the target value (NO in step S4), it reduces the opening of the oxygen flow rate adjustment valve 27 (step S5). This reduces the amount of oxygen contained in the supply water, and the dissolved oxygen concentration in the stored water decreases. After step S5, the controller 15 returns to step S1 and repeats each step.

[0030] On the other hand, in step S4, if the control device 15 determines that the dissolved oxygen concentration of the stored water does not exceed the target value (YES in step S4), the control device 15 returns to step S1 and repeats each step.

[0031] According to the control program for the oxygen dissolver 13 described above, the dissolved oxygen concentration of the stored water can be maintained close to the target value. However, the dissolved oxygen concentration of the stored water may fluctuate significantly depending on the activity of the aquaculture subject and external factors. In such cases, the control of the oxygen dissolver 13 alone may not be enough to maintain the dissolved oxygen concentration of the stored water within a certain range. For this reason, in this embodiment, the control program for the aeration device 14 described below is also implemented.

[0032] (Control Program of Aeration Device) Next, the control program of the aeration device 14 will be described. Fig. 3 is a flow diagram of the control program of the aeration device 14. The control program of the aeration device 14 is a program that supplements the dissolved oxygen concentration of the stored water, and is executed in parallel with the control program of the oxygen dissolving device 13 described above. The control program of the aeration device 14 is also executed by the control device 15.

[0033] When the control program for the aeration device 14 is executed, the control device 15 first acquires the dissolved oxygen concentration of the stored water (step S11). As described above, the control device 15 can acquire the dissolved oxygen concentration of the stored water by receiving a measurement signal from the dissolved oxygen concentration meter 12.

[0034] Next, the control device 15 determines whether the dissolved oxygen concentration of the stored water obtained in step S11 is below a predetermined first threshold (step S12). In this embodiment, the first threshold is a value smaller than the target value used in the control program of the oxygen dissolving device 13, and is the minimum dissolved oxygen concentration required for aquaculture. The first threshold may be a fixed value or a variable value that varies according to fluctuations in the target value.

[0035] If the control device 15 determines in step S12 that the dissolved oxygen concentration in the stored water has fallen below the first threshold value (NO in step S12), it opens the oxygen auxiliary valve 34 (step S13). If the oxygen auxiliary valve 34 is already open, in step S13, the oxygen auxiliary valve 34 remains open or the opening degree is increased. This releases oxygen into the stored water, and the dissolved oxygen concentration in the stored water increases. After step S13, the control device 15 returns to step S11 and repeats each step.

[0036] On the other hand, if the control device 15 determines in step S12 that the dissolved oxygen concentration of the stored water is not below the first threshold value (YES in step S2), the process proceeds to step S14.

[0037] Next, in step S14, the control device 15 determines whether the dissolved oxygen concentration of the stored water obtained in step S11 is above a second threshold value. In this embodiment, the second threshold value is a value greater than a target value used in the control program of the oxygen dissolving device 13. For example, the second threshold value is a dissolved oxygen concentration that is excessive for aquaculture. The second threshold value may be a fixed value or a variable value that varies in accordance with fluctuations in the target value.

[0038] If the control device 15 determines in step S14 that the dissolved oxygen concentration in the stored water exceeds the second threshold value (NO in step S14), it closes the oxygen auxiliary valve 34 (step S15). If the oxygen auxiliary valve 34 is already closed, in step S15, the oxygen auxiliary valve 34 remains closed or the opening degree is reduced. This allows the dissolved oxygen concentration in the stored water to gradually decrease due to the activity of the cultured subject, etc. After step S15, the control device 15 returns to step S11 and repeats each step.

[0039] On the other hand, in step S14, if the control device 15 determines that the dissolved oxygen concentration of the stored water does not exceed the second threshold value (YES in step S14), the control device 15 returns to step S11 and repeats each step.

[0040] According to the control program for the aeration device 14, even if the dissolved oxygen concentration of the stored water cannot be maintained constant by the oxygen dissolving device 13 alone, the dissolved oxygen concentration of the stored water can be maintained at least at the first threshold value or higher, i.e., at the minimum dissolved oxygen concentration required for aquaculture. Furthermore, since the dissolved oxygen concentration of the stored water can be maintained at the second threshold value or lower, consumption of oxygen due to excessive release into the stored water by the aeration device 14 can be suppressed.

[0041] (Modification) In the above embodiment, the amount of oxygen dissolved in the supply water is adjusted by controlling the oxygen dissolver 13 to maintain the dissolved oxygen concentration of the stored water at a target value. However, the aeration device 14 may also be controlled to maintain the dissolved oxygen concentration of the stored water at a target value. For example, the amount of oxygen dissolved in the supply water by the oxygen dissolver may be kept constant, and the amount of oxygen released into the stored water from the aeration device 14 may be adjusted to maintain the dissolved oxygen concentration of the stored water at a target value. Furthermore, for example, the dissolved oxygen concentration of the stored water may be maintained at a target value by adjusting both the amount of oxygen dissolved in the supply water by the oxygen dissolver and the amount of oxygen released into the stored water from the aeration device 14.

[0042] (Summary) The first item disclosed in this specification is an aquaculture facility that includes an aquaculture tank for storing water for aquaculture, an oxygen dissolution device that dissolves oxygen inside the supply water supplied to the aquaculture tank, and an aeration device that releases oxygen into the water stored in the aquaculture tank.

[0043] According to this configuration, since an aeration device is provided in addition to an oxygen dissolving device, it is possible to respond to changes in the dissolved oxygen concentration of the water stored in the water tank.

[0044] The second item disclosed in this specification is the aquaculture equipment described in the first item, wherein the oxygen dissolution device adjusts the amount of oxygen to be dissolved in the supply water based on a target value of the dissolved oxygen concentration of the stored water, and the aeration device increases the amount of oxygen released into the stored water when the dissolved oxygen concentration of the stored water falls below a first threshold value below the target value.

[0045] With this configuration, even if the oxygen dissolving device is unable to maintain the dissolved oxygen concentration of the stored water at the target value, the aeration device can maintain the dissolved oxygen concentration of the stored water higher than the first threshold value.

[0046] The third item disclosed in this specification is an aquaculture facility described in the first or second item, wherein the aeration device reduces the amount of oxygen released into the stored water when the dissolved oxygen concentration in the stored water exceeds a second threshold value that is higher than the target value.

[0047] This configuration makes it possible to suppress consumption of oxygen due to excessive release into the water stored in the aeration device.

[0048] The fourth item disclosed in this specification is an aquaculture facility described in any one of items 1 to 3, wherein the aeration device includes an emergency line that releases oxygen into the stored water in the event of a power outage.

[0049] With this configuration, even if the power supply to the aquaculture equipment is lost, oxygen can continue to be released into the stored water.

[0050] The fifth item disclosed in this specification is a method for adjusting a dissolved oxygen concentration in an aquaculture facility including an aquaculture tank for storing water for aquaculture, an oxygen dissolution device that mechanically dissolves oxygen inside the supply water supplied to the aquaculture tank, and an aeration device that releases oxygen into the stored water stored in the aquaculture tank, the method adjusting the amount of oxygen dissolved in the supply water by the oxygen dissolution device based on a target value of the dissolved oxygen concentration of the stored water, and increasing the amount of oxygen released from the aeration device into the stored water when the dissolved oxygen concentration of the stored water falls below a first threshold value that is lower than the target value.

[0051] According to this method, even if the oxygen dissolving device is unable to maintain the dissolved oxygen concentration of the stored water at the target value, the aeration device can maintain the dissolved oxygen concentration of the stored water higher than the first threshold value.

[0052] REFERENCE SIGNS LIST 11 Water tank 12 Dissolved oxygen concentration meter 13 Oxygen dissolving device 14 Aeration device 15 Control device 21 Supply line 22 Discharge outlet 23 Outlet 26 Oxygen dissolving device main body 27 Oxygen flow control valve 28 Oxygen supply line 29 Oxygen supply equipment 31 Auxiliary line 32 Emergency line 33 Oxygen supply equipment 34 Oxygen auxiliary valve 35 Oxygen tank 36 Emergency on-off valve 37 Auxiliary line nozzle 38 Emergency line nozzle 100 Aquaculture equipment

Claims

1. An aquaculture facility comprising: an aquarium for storing water for aquaculture; an oxygen dissolving device for dissolving oxygen inside the water to be supplied to the aquarium; and an aeration device for releasing oxygen into the water stored in the aquarium.

2. The aquaculture facility described in claim 1, wherein the oxygen dissolution device adjusts the amount of oxygen to be dissolved in the supply water based on a target value of the dissolved oxygen concentration of the stored water, and the aeration device increases the amount of oxygen released into the stored water when the dissolved oxygen concentration of the stored water falls below a first threshold value that is lower than the target value.

3. The aquaculture facility described in claim 2, wherein the aeration device reduces the amount of oxygen released into the stored water when the dissolved oxygen concentration in the stored water exceeds a second threshold value that is higher than the target value.

4. The aquaculture facility of claim 1, wherein the aeration device includes an emergency line that releases oxygen into the stored water in the event of a power outage.

5. A method for adjusting a dissolved oxygen concentration in an aquaculture facility comprising an aquaculture tank for storing water for aquaculture, an oxygen dissolution device for dissolving oxygen internally in supply water supplied to the aquaculture tank, and an aeration device for releasing oxygen into the stored water stored in the aquaculture tank, the method comprising: adjusting the amount of oxygen dissolved in the supply water by the oxygen dissolution device based on a target value of the dissolved oxygen concentration of the stored water; and increasing the amount of oxygen released from the aeration device into the stored water when the dissolved oxygen concentration of the stored water falls below a first threshold value that is lower than the target value.

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