Culture device and drainage unit

Abstract

To provide a drainage structure suitable for removing foreign bodies in an aquarium.SOLUTION: A culture device according to an embodiment comprises an aquarium 4 for rearing aquatic organisms, a water supply part for supplying rearing water to the aquarium 4, and a drainage part for draining the rearing water in the aquarium 4. The drainage part includes a drainage unit 100 provided in a flow passage for the rearing water in the aquarium 4. The drainage unit 100 includes: a hollow main body 102 extending in a direction crossing the flow passage; a filter part 104 comprising a plurality of rows of slits provided in the main body 102, and for introducing the rearing water into the main body 102 while restraining entry of foreign bodies; and a drainage port 106 provided in the main body 102, and connected to a drainage pipe 36.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a drainage structure applied to an aquaculture tank. [Background technology]

[0002] As the global demand for marine resources increases, efforts are underway to develop aquaculture technologies that will ensure a stable supply of aquatic organisms. In recent years, as the effects of global warming and marine pollution have become problems, land-based aquaculture, which has fewer of these impacts, has been attracting attention. Land-based aquaculture has the advantages of being less restricted by location than marine aquaculture, being less affected by weather and natural disasters by using indoor facilities, and reducing the burden that aquaculture places on the environment.

[0003] In land-based aquaculture systems, a circulation path is provided to circulate the water in the tanks used to raise aquatic organisms (also called "breeding water") while purifying it in order to keep the water clean. The tank's drain is provided with a drainage structure that captures foreign matter before it is discharged outside the tank (see Patent Document 1). In the drainage structure of Patent Document 1, a drain pipe is buried in the bottom of the tank, and a cylindrical filter is connected to the opening of the drain pipe. The filter has a mesh structure and is erected inside the tank. The filter captures foreign matter that attempts to flow into the drain, thereby preventing the foreign matter from being discharged into the circulation path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-129862 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in this type of drainage structure, the filter has a mesh structure and is prone to clogging with foreign matter. If the filter becomes clogged and drainage is hindered, this can cause a change in the water level in the aquarium. This can disrupt the circulation balance of the breeding water in the system and can cause problems with controlling the amount of oxygen supplied to the aquarium. In addition, if the aquatic organism is a crustacean such as a shrimp, the molted shell contains long, thin parts such as antennae and legs, which can be difficult to remove if they get caught in the mesh.

[0006] The present invention has been made in consideration of the above circumstances, and one of its objects is to provide a drainage structure suitable for removing foreign matter from within an aquarium. [Means for solving the problem]

[0007] One aspect of the present invention is an aquaculture device. The aquaculture device includes an aquarium for raising aquatic organisms, a water supply section that supplies rearing water to the aquarium, and a drainage section that drains the rearing water from the aquarium. The drainage section includes a drainage unit provided in a flow path of the rearing water in the aquarium. The drainage unit includes a hollow main body extending in a direction crossing the flow path, a filter section consisting of multiple rows of slits provided in the main body and introducing the rearing water into the main body while suppressing the intrusion of foreign matter, and a drain outlet provided in the main body and connected to a drain pipe.

[0008] Another aspect of the present invention is a drainage unit to be installed in an aquarium for breeding aquatic organisms. This drainage unit includes a hollow main body configured to extend in a direction crossing a flow path of breeding water in the aquarium, a filter section formed of a plurality of rows of slits provided in the main body and capable of introducing breeding water into the main body while suppressing the intrusion of foreign matter, and a drain outlet provided in the main body and connectable to a drain pipe provided in the aquarium. Effect of the Invention

[0009] According to the present invention, a drainage structure suitable for removing foreign matter from within a water tank can be provided. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing an overview of an aquaculture system according to an embodiment. [Diagram 2] FIG. 2 is a plan view showing a schematic diagram of the water tank and its surrounding structure. [Diagram 3] FIG. 13 is a diagram showing an installation mode of the drainage unit in the water tank. [Figure 4] FIG. 2 is a diagram showing the structure of a drainage unit. [Diagram 5] 13A and 13B are diagrams showing the effect of the drainage unit. [Figure 6] 13A and 13B are diagrams illustrating a configuration of a drainage unit according to a modified example. [Figure 7] 13A and 13B are diagrams illustrating the configuration and effect of a drainage unit according to another modified example. [Figure 8] 13A and 13B are diagrams illustrating a configuration of a drainage unit according to another modified example. [Figure 9] 13A and 13B are diagrams illustrating the effect of the drainage unit of the modified example. [Figure 10] 13A and 13B are diagrams illustrating an installation mode of a drainage unit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following embodiment and its modified examples, substantially the same components are denoted by the same reference numerals, and the description thereof will be omitted as appropriate.

[0012] FIG. 1 is a diagram illustrating an overview of an aquaculture system according to an embodiment. The aquaculture system 1 realizes closed-circulation land-based aquaculture, and includes an aquarium 4 for cultivating aquatic organisms 2, a circulation path 6 for circulating the water (breeding water) in the aquarium 4, a biological filtration tank 8 provided in the circulation path 6, and an aquaculture management device 10 for managing the cultivating of the aquatic organisms 2. A pump 12 is provided in the circulation path 6. The breeding water circulates through the circulation path 6 by driving the pump 12. The pump 12 functions as a "circulation device" that adjusts the amount of water circulated. These aquaculture facilities are placed in an indoor facility.

[0013] Land-based aquaculture methods are generally divided into a free-flowing method and a closed circulation method. The free-flowing method is a method in which water is taken from the sea or a river by a pump, supplied to an aquarium, and dirty water is drained from the aquarium, that is, the water is kept clean by water exchange. In contrast, the closed circulation method has a circulation path for reusing the water stored in the aquarium, and keeps the water clean by passing it through a filter tank installed in the circulation path. As a compromise between the free-flowing method and the closed circulation method, there is also a semi-circulation method in which the water is circulated while part of it is exchanged. In this embodiment, the closed circulation method is adopted among land-based aquaculture, thereby eliminating the introduction of pathogens from outside and reducing seasonal factors that affect the water temperature. The temperature of the water is set to a temperature suitable for the growth of the aquatic organisms 2.

[0014] In this embodiment, the aquatic organisms 2 are saltwater fish, but may be freshwater fish. They may also be shellfish, crustaceans, or other fish and shellfish. The composition of the breeding water is adjusted depending on whether the aquatic organisms 2 are saltwater organisms or freshwater organisms.

[0015] A physical filter 7 is provided downstream of the aquarium 4 in the circulation path 6, and a biological filtration tank 8 is provided downstream of that. A drainage unit 100 with a filtering function is also provided in the aquarium 4, and relatively small foreign matter that could not be removed by the drainage unit 100 is captured by the physical filter 7. That is, the drainage unit 100 functions as a primary filter, and the physical filter 7 functions as a secondary filter. Details of the drainage unit 100 will be described later.

[0016] Toxic ammonia is generated in the aquarium 4 due to the metabolic activity of the aquatic organisms 2 and the decomposition of organic matter such as leftover food. For this reason, the breeding water is circulated and passed through the biological filtration tank 8 for biological filtration, which breaks down the ammonia and converts it into less toxic nitrate. The biological filtration tank 8 holds nitrifying bacteria (microorganisms) that oxidize ammonia in oxygen-containing water and convert it into nitrite and then nitrate.

[0017] A foam separator 14 and a denitrification tank 16 are connected to the biological filtration tank 8. The water discharged from the water tank 4 and guided to the biological filtration tank 8 is guided to the foam separator 14 by the drive of a pump 18. The foam separator 14 separates the pollutants contained in the water by adsorbing them into foam and floating them to the surface, and then returns the water to the biological filtration tank 8.

[0018] The water nitrified in the biological filtration tank 8 is guided by the pump 20 to the denitrification tank 16 and then returned to the biological filtration tank 8. The denitrification tank 16 holds denitrifying bacteria and reduces the nitrate contained in the filtered water to nitrogen gas, which is released into the atmosphere. After being rendered harmless in this way, the water in the biological filtration tank 8 is pumped up by the pump 12 and supplied to the aquarium 4.

[0019] The aquaculture system 1 is further provided with an oxygen supplying device 22 and a feeding device 24. The oxygen supplying device 22 supplies oxygen to the water in the aquarium 4. The oxygen supplying device 22 functions as an "oxygen adjusting device" that adjusts the amount of oxygen supplied to the aquarium 4. The feeding device 24 supplies food to the aquarium 4. The feeding device 24 functions as a "feeding adjusting device" that adjusts the amount of food to be fed to the aquatic organisms in the aquarium. The pumps, the oxygen supplying device 22, and the feeding device 24 function as "environmental devices" for adjusting the environment in the aquarium 4. In this embodiment, the aquarium 4, the drainage unit 100, the oxygen supplying device 22, and the feeding device 24 constitute an aquaculture apparatus 50.

[0020] The aquaculture management device 10 functions as a control device that controls each environmental device of the aquaculture system 1 according to the environment in the aquarium 4. The aquaculture management device 10 maintains the amount of dissolved oxygen in the aquarium 4 within an appropriate range by controlling the oxygen supply device 22. When the ammonia concentration in the aquarium 4 exceeds a predetermined allowable range, the aquaculture management device 10 controls the operation of the pump 12 to increase the amount of circulating water, promoting biological filtration of the breeding water. The aquaculture management device 10 realizes appropriate feeding of the aquatic organisms 2 by controlling the feeding device 24. Through such control, an appropriate growth environment for the aquatic organisms 2 in the aquarium 4 can be maintained.

[0021] FIG. 2 is a plan view showing a schematic diagram of water tank 4 and its surrounding structure. The water tank 4 is a so-called raceway type water tank, and has semicircular (R-shaped) corners 4a at both ends in the longitudinal direction. A partition wall 30 extending longitudinally through the center of the width of the water tank 4 divides the water channel 32 in the width direction. A pair of divided water channels 32a, 32b are parallel to each other and connected at the corner 4a. A flow in one direction (counterclockwise in the figure) is generated in the annular water channel 32 (see the arrow in the figure).

[0022] A water supply pipe 34 is provided so as to penetrate the side wall of the aquarium 4. The water supply pipe 34 is connected to the downstream piping of the biological filtration tank 8 to form the circulation path 6, and functions as a "water supply section" that supplies the breeding water to the aquarium 4. The water supply pipe 34 extends inside the aquarium 4 and branches into multiple pipes (branch pipes 34a) below the surface of the breeding water. The open end (i.e., the water supply port) of each branch pipe 34a faces the downstream side of the aquarium 4, and the breeding water is discharged toward the downstream side, thereby generating the above-mentioned unidirectional water flow. In other words, the water supply pipe 34 functions as a "water flow generating section" that generates a flow of the breeding water in the aquarium 4.

[0023] Meanwhile, drainage units 100 are disposed near the upstream ends of the water channels 32a, 32b in the flow path of the aquarium 4, that is, in the regions near the ends of the respective corners 4a (hereinafter also referred to as "specific regions"). These specific regions are known to be regions where the water flow is likely to change direction at the corners 4a, causing localized vortexes, and where foreign matter contained in the water flow is likely to collect (see Patent Document 1). The drainage units 100 are disposed so that such foreign matter can be removed and the breeding water can be discharged. The drainage units 100 function as a "drainage section" that discharges the breeding water in the aquarium 4 to the outside.

[0024] FIG. 3 is a diagram showing an installation state of the drainage unit 100 in the water tub 4. As shown in FIG. The drainage unit 100 has a hollow main body 102 that is rectangular in plan view, and has a filter section 104 on the front surface facing the upstream side of the water tank 4. The drainage unit 100 is installed in the water tank 4 so as to cross the water channel 32. That is, one longitudinal end of the drainage unit 100 is fixed to the partition wall 30, and the other end is fixed to the side wall 4b of the water tank 4. A drain port 106 is provided at the other end of the drainage unit 100, and a drain pipe 36 is connected to it.

[0025] The drain pipe 36 is connected to the piping upstream of the physical filter 7 to form the circulation path 6. The tip of the drain pipe 36 penetrates the side wall of the aquarium 4 and is connected to the drain port 106 of the drainage unit 100 below the water surface Wf. A portion of the breeding water flowing through the water passage 32 is introduced into the main body 102 via the filter section 104 and is discharged from the drain port 106 to the drain pipe 36. The provision of the filter section 104 prevents foreign matter from entering the main body 102.

[0026] Fig. 4 is a diagram showing the structure of the drainage unit 100. Fig. 4(A) is a perspective view, Fig. 4(B) is a side view, and Fig. 4(C) is a cross-sectional view taken along line AA of Fig. 4(B). As shown in Figure 4(A), the main body 102 of the drainage unit 100 is obtained by assembling metal or resin plate materials, and is a hollow body that has a trapezoidal shape when viewed from the side, and has a front surface 110, a pair of side surfaces 112, a rear surface 114, an upper surface 116, and a lower surface 118.

[0027] 4(B), the upper surface 116 and the lower surface 118 are horizontal surfaces, and the side surface 112 and the rear surface 114 are vertical surfaces. The front surface 110 is an inclined surface that forms a predetermined angle θ with respect to the horizontal surface, and multiple rows of slits S are provided side by side on the inclined surface. The angle θ can be set appropriately, but is preferably set in the range of 10 to 80 degrees.

[0028] More specifically, a wedge wire screen 120 is provided at the front end opening of the main body 102 surrounded by the upper surface 116, the lower surface 118, and the pair of side surfaces 112, and the smooth surface of the wedge wire screen 120 constitutes the front surface 110. As shown in FIG. 4(C), the wedge wire screen 120 is configured by arranging a plurality of wires 122 having a triangular cross section at equal intervals in the horizontal direction, and slits S are formed between adjacent wires 122. That is, a plurality of rows of slits S are arranged in the longitudinal direction of the main body 102, and each slit S is formed so as to extend in the vertical direction of the main body 102. In this embodiment, the width of the slits S is set to about 2 to 3 mm, but this value can be set appropriately.

[0029] This wedge wire screen 120 functions as the filter section 104. The rearing water is introduced into the inside of the main body 102 through the multiple rows of slits S in the wedge wire screen 120, guided in the longitudinal direction of the main body 102, and then discharged from the drainage outlet 106 (see the two-dot chain line arrow). The spacing between adjacent wires 122 becomes wider toward the inside of the main body 102, which promotes the passage of the rearing water and makes it less likely to become clogged even when small foreign objects pass through.

[0030] As shown in Fig. 3, when the drainage unit 100 is installed in the aquarium 4, the front surface of the main body 102 faces the upstream side, and the back surface faces the downstream side. The front surface of the main body 102 forms an inclined surface that slopes downward toward the downstream side. Because the lower surface of the main body 102 is sufficiently separated from the bottom of the aquarium 4, the culture water in the aquarium 4 passes below the drainage unit 100 and circulates through the water channel 32, except for a portion that is introduced into the drainage unit 100. In other words, the drainage unit 100 does not obstruct the flow of the culture water in the aquarium 4.

[0031] Fig. 5 is a diagram showing the effect of the drainage unit 100. Fig. 5(A) shows an installation mode of the drainage unit 100 of this embodiment, and Fig. 5(B) shows an installation mode of a modified example. As shown in Fig. 5(A), the drainage unit 100 is arranged in the water tank 4 at a height such that the upper part of the filter unit 104 is exposed above the water surface Wf. The depth h1 of the submerged part of the drainage unit 100 is smaller than the height h2 from the bottom of the water tank 4 to the lower surface of the drainage unit 100 (h1 < h2). In this embodiment, the height h (= h1 + h2) of the water surface Wf is set to about 60 cm, and the submerged depth h1 is set to about 20 cm, but these values can be set as appropriate.

[0032] With such an installation configuration, a part of the breeding water flowing through the water channel 32 of the water tank 4 can be introduced into the drainage unit 100 and drained. At this time, among the foreign matters contained in the breeding water flowing through the upper part of the water channel 32, the foreign matter c1 that is heavier than water and larger than the width of the slit S can be guided obliquely downward along the front surface of the main body 102.

[0033] As described above, since the front surface of the main body 102 is inclined downward toward the downstream side, the breeding water also easily flows downstream along the inclined surface. Therefore, it is easy to guide the foreign matter c1 downstream on the flow of the breeding water. The foreign matter c1 settles on the bottom of the water tank 4 during the process of circulating with the breeding water. Therefore, it can be easily removed during cleaning. A collection location for the foreign matter c1 may be set at a predetermined position on the bottom of the water tank 4. A cleaning device for sucking and removing the foreign matter c1 may be provided at the collection location.

[0034] On the other hand, relatively light and large foreign matters c2 (floating matters) will flow on the water surface Wf, but can be captured at the upper part of the filter unit 104. Such foreign matters c2 will adhere to the front surface of the drainage unit 100, but since the structure of the filter unit 104 is composed of vertically long slits instead of a mesh, it can be easily removed during cleaning. In addition, since the height h3 of the submerged part of the filter unit 104 is sufficiently larger than the height h4 of the exposed part from the water surface Wf, the adhesion of the foreign matter c2 does not hinder the introduction of the breeding water into the main body 102.

[0035] In the modified example shown in FIG. 5(B), since the entire drainage unit 100 is submerged, it is difficult for the drainage unit 100 to capture the foreign matter c2, but it is possible to perform the same drainage treatment as in this embodiment. Furthermore, the foreign matter c1 can be guided to the bottom of the water tank 4 to encourage sedimentation. It is possible to deal with the foreign matter c2 by having an operator scoop it up with a net or by installing a separate filter for capture. Aside from the drainage unit 100, equipment for removing foreign matter floating on the water surface of the water tank 4 may be provided.

[0036] As described above, in this embodiment, a flow of rearing water is generated in the aquarium 4, and the drainage unit 100 is provided in the flow path, so that the rearing water can be drained while removing foreign matter contained in the rearing water. The main body 102 of the drainage unit 100 is disposed so as to cross the flow path, and an inlet for rearing water is provided on the front side, so that rearing water flowing from the upstream side can be easily introduced as it is, and its drainage can be promoted. Although the drainage unit 100 crosses the flow path, the bottom surface of the main body 102 is sufficiently separated from the bottom of the aquarium 4, so that the rearing water can also flow below the main body 102. Therefore, the drainage unit 100 does not obstruct the flow (circulation) of the rearing water in the aquarium 4.

[0037] In the drainage unit 100, multiple rows of slits S provided on the front surface of the main body 102 function as a filter section 104, preventing foreign matter from entering the inside of the main body 102. By making the filter section 104 a slit structure rather than a mesh structure, clogging caused by relatively small foreign matter can be prevented. This makes it possible to prevent fluctuations in the water level in the aquarium 4 caused by providing the drainage unit 100. This means that it is easier to maintain a circulating balance of the breeding water in the aquaculture system 1, and easier to maintain a good environment in the aquarium 4.

[0038] In particular, the filter portion 104 has multiple rows of slits S formed to extend vertically, that is, in the direction along the flow of the rearing water on the outer surface of the main body 102. This makes it difficult for relatively large foreign objects flowing with the rearing water to become caught. If the aquatic organism 2 is a crustacean such as a shrimp, the molted shell has long and thin parts such as antennae and legs, and even if such foreign objects become caught in the filter portion 104, they are easy to remove. This makes it easy to maintain the drainage unit 100.

[0039] Since the front surface of the main body 102 on which the filter unit 104 is provided is an inclined surface, the force of the water flow along the surface of the main body 102 can be maintained. Therefore, it is easy to guide foreign matter downward by letting the breeding water flow along the inclined surface. Even if foreign matter adheres to the surface of the filter unit 104, it is easy to peel it off by the water flow. This effectively contributes to preventing foreign matter from getting caught or clogging in the filter unit 104. In addition, the flow of the breeding water can be used to guide the foreign matter downstream. Since the foreign matter settles to the bottom of the aquarium 4 in the process of circulating inside the aquarium 4 together with the breeding water, it can be removed by subsequent cleaning. This makes it easier to keep the inside of the aquarium 4 clean. It also reduces the burden on workers involved in cleaning.

[0040] In addition, since the upper part of the drainage unit 100 is exposed above the water surface of the water tank 4 and the filter section 104 is located near the water surface, it is easy to capture relatively large floating objects. In addition, daily maintenance of the filter section 104 is also easy. By providing the drainage pipe 36 on the side wall of the water tank 4 in accordance with the position of this drainage unit 100, the piping structure can be simplified. By configuring the drainage pipe 36 to be connected to the side wall of the water tank 4 without being buried below the water tank 4, the inside of the drainage pipe 36 can be easily cleaned and its maintenance is also easy. As a result, the generation of hydrogen sulfide gas due to the accumulation of sludge in the drainage pipe 36 can also be prevented.

[0041] Although a preferred embodiment of the present invention has been described above, it goes without saying that the present invention is not limited to that specific embodiment, and various modifications are possible within the scope of the technical concept of the present invention.

[0042] [Variations] Fig. 6 is a diagram showing the configuration of a drainage unit according to a modification. Fig. 6(A) to (C) show modifications 1 to 4. The drainage unit of each modification has a different main body shape from that of the above embodiment. As shown in Fig. 6(A), in the drainage unit of the first modified example, the rear surface 214 of the main body 210 is an inclined surface. The rear surface 214 is inclined downward toward the upstream side. This makes it difficult for foreign matter to adhere to the rear surface 214.

[0043] As shown in FIG. 6(B), in the drainage unit of the second modification, the front surface 222 of the main body 220 on which the filter section is formed has a curved surface (R-shaped) at the bottom. That is, the bottom portions of the wires 226 constituting the wedge wire screen 224 are curved. As shown in FIG. 6(C), in the drainage unit of the third modification, the entire front surface 232 of the main body 230 has a curved surface (R-shaped). That is, the wires 236 constituting the wedge wire screen 234 have a curved shape. Compared to the flat surfaces of the above embodiment, these curved surfaces have a shape that is positioned further downstream as they go downward, so that the flow resistance of the rearing water toward the downstream side can be reduced and foreign matter can be easily guided downstream.

[0044] 6(D), the drainage unit of the fourth modified example has curved surfaces (R-shaped) across the front, bottom, and back surfaces of the main body 240. That is, each wire 246 constituting the wedge wire screen 244 may have a semicircular shape, and each slit S may have a curved surface 242 that extends from the front surface to the back surface of the main body 240.

[0045] 7A and 7B are diagrams showing the configuration and effect of a drainage unit according to another modified example. Fig. 7(A) shows the configuration of modified example 5. Fig. 7(B) shows the effect of modified example 5. The drainage unit of the fifth modified example differs from the above-mentioned embodiment in that it has a horizontal slit structure as a filter section. As shown in Fig. 7(A), a wedge wire screen 320 is provided on the front surface 110 of the main body 302. The wedge wire screen 320 is configured by arranging a plurality of wires 322 extending in the horizontal direction at equal intervals in the vertical direction, and slits S are formed between adjacent wires 322. In other words, each slit S is formed to extend in the horizontal direction.

[0046] As shown in Fig. 7(B), in this modified example, the front surface 110 of the main body 302 has an inclined surface, so that the foreign object c1 can be guided downstream along the inclined surface. However, since multiple gaps are formed from the top to the bottom of the inclined surface, it is considered that the foreign object c1 is more likely to be caught compared to the above embodiment. In other words, the configuration of the above embodiment is preferable in terms of making it difficult for the foreign object c1 to be caught.

[0047] Fig. 8 is a diagram showing the configuration of a drainage unit according to another modified example. Figs. 8(A) to (C) show modified examples 6 to 8. The drainage unit of each modified example has a different main body structure from the above embodiment. Fig. 9 is a diagram showing the effect of modified example 7.

[0048] As shown in FIG. 8(A), in the drainage unit of Modification 6, an opening 412 is provided on the top surface of the main body 410. Even if such a configuration is adopted, there is no particular problem as long as the water tank is installed indoors and the top of the drainage unit is exposed above the water surface (see FIG. 3), and the same effect as in the above embodiment can be obtained. In addition, since the top surface of the drainage unit is open, there is also the advantage that the inside of the main body 410 can be easily cleaned. Note that instead of opening the entire top surface of the main body 410 as shown in the figure, an opening may be provided in part of the top surface.

[0049] As shown in Fig. 8(B), in the drainage unit of the seventh modified example, a filter section 104 is formed on the lower surface 118 of the main body 420. The multiple rows of slits S of the filter section 104 are formed to extend in the front-rear direction, that is, in the direction along the flow of the rearing water along the outer surface of the main body 420. Therefore, like the above embodiment, foreign matter flowing with the rearing water is less likely to become caught. Although no slits are provided on the front surface 110 of the main body 420, it is like the above embodiment in that it has an inclined surface. Therefore, it is easy to guide the rearing water downward along the inclined surface.

[0050] 9, in the configuration of Modification 7, the front surface of the main body 420 becomes the wall surface of the waterway, and the rearing water flowing from the upstream side cannot be introduced directly into the main body 420. However, since the main body 420 is located at the top of the aquarium 4, a flow contraction section CA is formed between the bottom of the aquarium 4 and the main body 420, and the rearing water is also pushed toward the opening on the bottom of the main body 420 (i.e., the multiple rows of slits S) to reduce the flow resistance in the flow contraction section CA. This allows the rearing water to be introduced into the inside of the main body 420.

[0051] As shown in Fig. 8(C), in the drainage unit of the eighth modified example, a filter section 104 is formed on the lower surface 118 and rear surface 114 of the main body 430. The filter section 104 on the rear surface is also configured with multiple rows of vertically long slits S arranged in the longitudinal direction (direction crossing the flow path) of the main body 430. With this configuration, rearing water can be introduced from the rear surface side of the main body 430 as well.

[0052] FIG. 10 is a diagram showing an installation mode of a drainage unit according to a modified example. In the above embodiment, an example was shown in which the drainage unit 100 was installed in a raceway-type water tub 4. In this modified example, the drainage unit 100 is installed in a circular water tub 504. A support pillar 510 is provided in the center of the water tub 504. The drainage unit 100 is installed so as to span between a side wall 504b (inner wall) of the water tub 504 and the support pillar 510.

[0053] A water supply pipe 34 and a drain pipe 36 are connected to a side wall 504b of the water tank 504. The drain pipe 36 is connected to the drain outlet 106 of the drainage unit 100. The open end of the water supply pipe 34 (i.e., the water supply outlet) is oriented in a direction along the inner circumference of the water tank 504, thereby generating a unidirectional water flow (rotating flow).

[0054] In this modified example, the drainage unit 100 is also disposed so as to cross the flow path, thereby facilitating the introduction of rearing water into the drainage unit 100 and its drainage. Since the lower surface of the drainage unit 100 is sufficiently separated from the bottom of the aquarium 504, the flow (circulation) of the rearing water is not substantially impeded. By installing the drainage unit 100, it is possible to obtain the same effects as in the above embodiment. It is to be noted that the drainage unit 100 may of course be replaced with any of the modified examples described above.

[0055] [Other variations] In the above embodiment, an example was shown in which a wedge wire screen was used as the filter portion 104. In a modified example, a bar screen or other screen in which rods or plates are arranged in parallel to form a slit structure may be used. By making the filter portion slit-shaped instead of mesh-shaped, the same effect as in the above embodiment can be obtained.

[0056] In the above embodiments and modified examples, examples are shown in which the filter unit is provided on the front surface of the main body, on the underside, and on the underside and back surface, but which surface the filter unit is provided on, and the combination of surfaces in the case of providing the filter unit on multiple surfaces, can be selected as appropriate.

[0057] In the above embodiment, an example was shown in which the water supply pipe 34 was installed in a creative way to function as a "water flow generating unit." In a modified example, a pump may be installed in the aquarium to function as a "water flow generating unit." This allows the water supply pipe to be installed with greater freedom, for example by positioning the water supply port above the aquarium. In the above embodiment, the water flow was generated by directing the water supply port of the water supply pipe 34 downstream, but the "water flow generating unit" may be provided by providing a structure for directing the rearing water downstream near the water supply port in the aquarium 4. For example, a partition wall may be partially provided upstream of the water supply port to generate a water flow toward the downstream side.

[0058] In the above embodiment, an example has been shown in which the drainage unit 100 is installed near the corner 4a of the raceway-type water tub 4. In a modified example, the drainage unit 100 may be installed at a position away from the corner 4a, such as near the center of the water tub 4 in the longitudinal direction. Alternatively, the drainage unit 100 may be installed at the corner 4a.

[0059] In the above embodiment, an example has been shown in which the drainage unit 100 is installed so as to cross the water passage 32, one end of the drainage unit 100 is fixed to the partition wall 30, and the other end is fixed to the side wall 4b. In a modified example, pillars may be provided near the partition wall 30 and near the side wall 4b of the water tank 4, and the drainage unit may be supported by these pillars. In other words, the main body of the drainage unit may extend in a direction crossing the flow path, but may not span the entire width of the water passage.

[0060] In the above embodiment, as shown in Fig. 2, an example has been shown in which the drainage unit 100 extends in the width direction of the water channel 32, that is, extends at a right angle to the water channel 32 in a plan view. In a modified example, the drainage unit 100 may be installed so as to form a predetermined angle (e.g., 0 to 80 degrees) with respect to the water channel 32 in a plan view.

[0061] In the above embodiment, an example has been shown in which the aquaculture equipment of the aquaculture system 1 is arranged in an indoor facility, but for example, any aquaculture equipment other than the water tank may be installed outdoors.

[0062] In the above embodiment and modified example, the drainage unit is applied to a tank for closed circulation land-based aquaculture, but it may be applied to a tank for semi-circulation land-based aquaculture in which the breeding water is circulated while a part of it is replaced. Alternatively, it may be applied to a tank for land-based aquaculture using a flow-through method. Since it becomes easy to remove foreign matter in the tank, it is possible to suppress pollution caused by drainage into the sea or rivers.

[0063] Although not mentioned in the above embodiment, oxygen is consumed during the decomposition of ammonia in the biological filtration tank 8, so that the biological filtration tank 8 may also be provided with an oxygen supply device (second oxygen regulator).

[0064] In the above embodiment, as shown in Fig. 1, the oxygen supply device 22 is installed in the aquarium 4, but it may be installed in front of the aquarium 4, that is, upstream of the aquarium 4 in the circulation path 6. This may increase the oxygen concentration in the circulating breeding water (the circulating water itself).

[0065] In the above embodiment, the oxygen regulator is exemplified by the oxygen supply device 22. In a modified example, an aeration device or the like may be provided in the water tank as the oxygen regulator, and the dissolved oxygen concentration may be adjusted by controlling the output thereof.

[0066] In the above embodiment, as shown in Fig. 2, the water supply pipe 34 is branched into a plurality of pipes inside the water tank 4. In a modified example, the water supply pipe may not be branched inside the water tank (i.e., the water supply pipe may have one water supply port).

[0067] Although not mentioned in the above embodiment, a separate facility for removing foreign matter floating on the water surface of the tank may be provided upstream of the drainage unit.

[0068] In the above embodiment, an example was shown in which a wedge wire screen is provided at the opening of the body of the drainage unit, and a slit is formed between adjacent wires to realize a filter section. In a modified example, the body of the drainage unit may be processed so that a slit that becomes the filter section is formed. For example, the slit may be formed by producing the body using a 3D printer.

[0069] The present invention is not limited to the above-mentioned embodiment and modified examples, and the components can be modified without departing from the gist of the present invention. Various inventions can be formed by appropriately combining multiple components disclosed in the above-mentioned embodiment and modified examples. In addition, some components can be deleted from all the components shown in the above-mentioned embodiment and modified examples. [Explanation of symbols]

[0070] 1 Aquaculture system, 2 Aquatic organisms, 4 Aquarium, 6 Circulation, 7 Physical filter, 8 Biological filtration tank, 10 Aquaculture management device, 12 Pump, 14 Foam separator, 16 Denitrification tank, 18 Pump, 20 Pump, 22 Oxygen supply device, 24 Feeding device, 30 Partition wall, 32 Waterway, 34 Water supply pipe, 36 Drain pipe, 50 Aquaculture device, 100 Drain unit, 102 Main body, 104 Filter part, 106 Drain port, 110 Front, 112 Side, 114 Rear, 116 Top, 118 Bottom, 210 Main body, 214 Rear, 220 Main body, 222 Front, 230 Main body, 232 Front, 302 Main body, 410 Main body, 412 Opening, 420 Main body, 430 Main body, 504 Water tank, 510 support, CA contraction section, S slit, Wf water surface, c1 foreign object, c2 foreign object.

Claims

1. an aquarium for rearing aquatic organisms; A water supply unit that supplies breeding water to the aquarium; A drainage section for draining the breeding water in the aquarium; Equipped with The drainage section includes a drainage unit provided in a flow path of rearing water in the aquarium, The drainage unit includes: a hollow body extending transversely to the flow passage; a filter section that is formed of a plurality of rows of slits provided in the main body and that introduces rearing water into the inside of the main body while preventing the intrusion of foreign matter; A drain port provided in the main body and connected to a drain pipe; 23. Aquaculture equipment comprising:

2. The aquaculture device according to claim 1 , wherein the plurality of rows of slits are formed in the main body so as to extend in a direction along a flow of rearing water along an outer surface of the main body.

3. The main body has a front surface facing the upstream side of the water tank, a lower surface spaced from the bottom of the water tank, and a rear surface facing the downstream side of the water tank, The aquaculture device according to claim 2 , wherein the front surface of the main body has an inclined surface that slopes downward toward the downstream side.

4. The filter portion is provided on the inclined surface, The aquaculture device according to claim 3 , wherein the plurality of rows of slits each extend in the vertical direction of the front surface and are arranged in parallel in the longitudinal direction of the main body.

5. The aquaculture device according to claim 4 , wherein the drainage unit is disposed in the aquarium so that an upper portion of the filter portion is exposed above the water surface.

6. the drain pipe is connected to a side wall of the aquarium; The aquaculture device according to claim 1 , wherein the drainage outlet of the drainage unit is connected to the drain pipe below the water surface of the aquarium.

7. The water supply unit includes a water supply pipe connected to a side wall of the water tank, The aquaculture device according to claim 6 , wherein the water supply pipe functions as a water flow generating section by discharging rearing water toward a downstream side of the aquarium.

8. A drainage unit to be installed in an aquarium for raising aquatic organisms, A hollow body configured to extend in a direction transverse to a flow path of the rearing water in the aquarium; a filter section that is formed of a plurality of rows of slits provided in the main body and that is capable of introducing rearing water into the inside of the main body while suppressing the intrusion of foreign matter; A drain outlet provided in the main body and connectable to a drain pipe provided in the water tank; A drainage unit comprising:

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