JP7307987B1 - Land-based aquaculture apparatus and land-based aquaculture method for algal bodies - Google Patents

Abstract

An object of the present invention is to suppress uneven distribution of algal bodies in a culture tank, thereby enabling more efficient land-based cultivation of large alga bodies such as seaweed. A terrestrial aquaculture apparatus of the present invention comprises an aquaculture tank containing aquaculture water and a stirrer having paddle blades that rotate along the surface of the water, the aquaculture tank having a diameter of 5 m or more, the aquaculture tank containing algal bodies having a length of 50 mm or more, the paddle blades having N or more arms extending radially from a rotation center (where N is a natural number of 1 or more), and the arms being provided with paddles for agitating the aquaculture water. wherein the width of the paddle is 20% or more and 90% or less of the radius of the culture tank, and the distance between the bottom of the culture tank and the bottom of the paddle is 50 mm or more and 250 mm or less. [Selection drawing] Fig. 28a

Description

Application of Article 30, Paragraph 2 of the Patent Act June 21, 2020 TV broadcast June 21, 2020 website March 7, 2022 website April 28, 2022 website Ordinance Performance comparison test on July 19, 1999

TECHNICAL FIELD The present invention relates to a land-based seaweed farming apparatus and land-farming method for farming seaweed on land.

As a technique for cultivating seaweed on land, for example, Patent Document 1 discloses preparing seedlings in which seaweed spores or germinated spores are agglomerated and cultivating them in a tank (Patent Document 1). 1, paragraphs [0007] to [0009]).

In land-based seaweed farming, it is important to irradiate seaweed with light. In order to perform light irradiation efficiently, the invention described in Patent Document 1 describes stirring in a water tank (see paragraph [0010] of Patent Document 1). The seedlings (algal masses) are made to flow by generating running water by agitation, thereby irradiating the seedlings with light.

Patent Literature 2 discloses a land-based aquaculture apparatus for seaweeds. This apparatus prepares an aquaculture tank having a U-shaped or semicircular cross-sectional shape and a curved wall surface at the bottom. It is made to flow down like a jet. As a result, the aquaculture seawater in the aquaculture tank swirls along the curved wall surface, and the aquaculture seawater stored in the aquaculture tank can be agitated (see paragraph [0009] of Patent Document 2).

Patent Document 2 further introduces the use of ground seawater and deep ocean water as seawater for aquaculture (see paragraph [0001] of Document 2).

Patent Literature 3 further describes a method for cultivating seaweeds on land, in which alga bodies are efficiently agitated by a circular culture tank and the rotation of paddle blades. Furthermore, Patent Document 4 describes a method for more efficiently agitating large-sized alga bodies.

JP-A-2002-176866 JP 2012-213351 A JP 2020-048414 A Japanese Patent Application No. 2021-001162

When agitating large alga bodies such as seaweed with a length of several centimeters or more in a pond-shaped culture tank, etc., there are various problems that were not observed when agitating microalgae with a length of several μm to several tens of μm. need to overcome. An object of the present invention is to solve the problem of uneven distribution of algae in a culture tank when agitating algae.
Microalgae are so small that they behave like a liquid or colloidal solution in aquaculture tanks. For example, when India ink is poured into a container containing water, microalgae spread throughout the culture tank like a solution in the same way that India ink spreads throughout the container. do not have. It is sufficient to at least properly stir the water with a stirrer.
On the other hand, large algal bodies such as seaweed, which is the object of the present invention, cannot be well stirred simply by stirring the water in the culture tank with a stirrer because of its size and weight. For example, in Figs. 29a and 29d, the algal bodies are concentrated near the center of the stirrer in the culture tank, and the distribution within the culture tank is highly uneven. If the distribution is uneven, the number of alga bodies placed in the shadow of other alga bodies increases, and the light irradiation of the whole alga bodies becomes uneven, resulting in deterioration of cultivation efficiency.
Although the land-based seaweed farming apparatuses described in Patent Documents 3 and 4 by the present inventors were unprecedented and revolutionary, there is a demand for more efficient land-based farming of seaweeds. .

The land-based aquaculture apparatus for algal bodies of the present invention comprises an aquaculture tank containing aquaculture water and an agitator having paddle blades that rotate along the water surface, wherein the aquaculture tank has a diameter of 5 m or more,
including algal bodies with a length of 50 mm or more in the culture tank,
The paddle blade has N or more arms extending radially from the center of rotation (where N is a natural number of 3 or more), and the arms are provided with paddles for agitating the aquaculture water,
The width of the paddle is 20% or more and 90% or less of the radius of the culture tank,
The distance between the bottom of the culture tank and the bottom of the paddle is 50 mm or more and 250 mm or less.
Further, the method for cultivating algal bodies on land according to the present invention comprises an aquaculture tank containing aquaculture water and an agitator having paddle blades that rotate along the surface of the water, wherein the aquaculture tank has a diameter of 5 m or more,
including algal bodies with a length of 50 mm or more in the culture tank,
The paddle blade has N or more arms extending radially from the center of rotation (where N is a natural number of 3 or more), and the arms are provided with paddles for agitating the aquaculture water,
The width of the paddle is 20% or more and 90% or less of the radius of the culture tank,
The distance between the bottom of the culture tank and the bottom of the paddle is 50 mm or more and 250 mm or less.

The imbalance in the arrangement distribution of the algal bodies in the culture tank is suppressed, and it is possible to more efficiently cultivate large algal bodies such as seaweed on land.

An example of an aquaculture facility (illustration) An example of an aquaculture facility (photo) Aquaculture tank with a diameter of 20m (photo) Planar shape of aquaculture tank and relation between inscribed circle and diameter The schematic diagram which shows an example of the procedure of the land-based aquaculture method of seaweeds. The schematic diagram which shows another example of the procedure of the land-based aquaculture method of seaweeds. The schematic diagram which shows the process which produces seedlings. (a) is the first-stage aquaculture process using a culture tank with a diameter of 1 m, (b) is the second-stage aquaculture process using a culture tank with a diameter of 2 m, and (c) is a culture tank with a diameter of 5 m. (d) is a schematic diagram showing the 4th stage culturing process using a culture tank with a diameter of 10 meters. Photographs of actual algal bodies grown to various lengths The top view which shows a stirrer. FIG. 11 is a side view of the agitator of FIG. 10; Plan view showing the stirrer Side view of the stirrer of FIG. Example of the stirrer of FIG. 10 without paddles on the arms Example of the stirrer of FIG. 12 without paddles on the arms Photograph of a culture tank with a diameter of 20m Photograph of a culture tank with a diameter of 20m Reinforcement of stirrer arm of 20m diameter aquaculture tank Relationship between the center of rotation of paddle blades and the culture tank Relationship between the center of rotation of paddle blades and the culture tank Relationship between the center of rotation of paddle blades and aquaculture tank (with water flow) Relationship between the center of rotation of paddle blades and aquaculture tank (with water flow) Relationship between the trajectory of the paddle tip of the paddle blade and the culture tank Relationship between the trajectory of the paddle tip of the paddle blade and the culture tank Preferred situation of the present invention Illustration of fixing the stirrer at two points Illustration of fixing the stirrer at three points Example of a stirrer with one arm Example of a stirrer with two arms Schematic of the invention Schematic of the invention Photograph of a comparative example of the present invention Photograph of an embodiment of the present invention Photograph of an embodiment of the present invention Photo of a comparative example of the present invention (aquaculture tank in the center of the photo) Photo of an embodiment of the present invention (aquaculture tank in the center of the photo) Photo of an embodiment of the present invention (aquaculture tank in the center of the photo) Photo of an embodiment of the present invention (aquaculture tank in the center of the photo) Photo of an embodiment of the present invention (aquaculture tank in the center of the photo) Photo of an embodiment of the present invention (aquaculture tank in the center of the photo) Photo of an embodiment of the present invention (aquaculture tank in the center of the photo) Schematic of the invention Schematic of the invention Schematic of the invention Schematic of the invention Schematic of the invention

The present inventors have newly found that it is important to maintain an appropriate distance between the bottom of the culture tank and the bottom of the paddle in order to efficiently agitate the algal bodies in the culture tank. Before explaining the features of the present invention, the background (variation) of the present invention, namely, the aquaculture facility, the aquaculture tank, the aquaculture system, and the land-based aquaculture method, will be explained. After that, the features of the present invention will be described.
<1. Background (variation) of the present invention>
[Aquaculture facility]
[Aquaculture tank]
[Aquaculture system]
[Land-based aquaculture method]
<1. Production of seedlings>
<2. Release of seedlings>
<3. Raising seedlings>
(Aquaculture tanks at each stage)
(Length of alga body)
<4. Installation of stirrer>
(1) Structure of stirrer (first stirrer)
(Second stirrer)
(Third Stirrer/Fourth Stirrer)
(2) Stirrer installation position 1
(3) Stirrer installation position 2
(4) Insertion of agitator and fixation of position <2. Features of the present invention>

<1. Background (variation) of the present invention>
[Aquaculture facility]
As shown in FIG. 1, the aquaculture facility 11 of this embodiment is installed on the coast 13 adjacent to the sea 12 and includes a plurality of land-based aquaculture apparatuses 101 . Each land-based aquaculture apparatus 101 is mainly composed of an aquaculture tank 111 containing aquaculture seawater 51 (aquaculture water) used for culturing seaweed seedlings 31 (algal bodies), and includes a plurality of aquaculture tanks 111 of different sizes. ing. This is an example of land-based aquaculture using sunlight.
In the aquaculture facility 11, the nine on the left side shown in Fig. 1 have a diameter of 10 meters, the row adjacent to this and the one on the right side have a diameter of 5 meters, and the row of seven on the right side has a diameter of 2 meters, and beyond that. 1 meter diameter culture tanks 111 are arranged in two rows of eight. For convenience of explanation, the culture tank 111 with a diameter of 1 m will be referred to as a culture tank 111a, the culture tank 111 with a diameter of 2 m as a culture tank 111b, the culture tank 111 with a diameter of 5 m as a culture tank 111c, and the culture tank 111 with a diameter of 10 m as a culture tank. 111d.
Figure 2 is a photograph of an actual aquaculture facility. The largest aquaculture tank in the foreground is 10 meters in diameter. The present invention may further comprise an aquaculture tank having a diameter of 20 meters or more as shown in FIG.

Moreover, the size of the culture tank is not limited to 1, 2, 5, 10 and 20 meters in diameter, and any size can be selected.
For example, 1m, 2m, 5m, 8m, 10m, 12m, 13m, 14m, 15m, 16m, 18m, 20m, 22m, 24m, 25m, 26m , 28 meters, 30 meters, 35 meters, 40 meters, etc. A plurality of types (eg, 4 to 6 types) of culture tanks can be selected as appropriate.

[Aquaculture tank]
The shape of the inner wall of the aquaculture tank is a planar view (shape seen from above) considering the fact that the paddle blades of the stirrer rotate along the water surface in the horizontal plane, the stirring efficiency of the algal body, the ease of production, the strength, and the cost. A circular shape is desirable, but the shape may not be circular as long as the shape is close to a circular shape.
For example, it may be polygonal. If the shape is 10 or more, it can be regarded as a substantially circular shape, but it may be 5 or more. For example, it may be an ellipse. In the case of an ellipse, the oblateness is preferably 0.4 or less. More preferably, the flatness is 0.2 or less, more preferably 0.1 or less.
In the present invention, the substantially circular aquaculture tank includes not only these circular, polygonal, and elliptical shapes, but also circular, polygonal, and elliptical shapes with some distortion or unevenness. Considering the manufacturing process of the aquaculture tank and the aged deterioration in the field, some distortion and unevenness are expected.
The diameter of the aquaculture tank of the present invention is defined as the diameter of the largest inscribed circle that inscribes the shape of the inner wall of the aquaculture tank in plan view. FIG. 4 shows the relationship between the planar shape of circular, elliptical, pentagonal, and decagonal culture tanks, the inscribed circle, and the diameter.
In the present invention, the center of the culture tank is defined as the geometric center of the planar shape of the inner wall of the culture tank.

[Aquaculture system]
As shown in FIG. 5, the aquaculture system using the land-based aquaculture apparatus 101 of the present embodiment utilizes the geographical advantage of being installed on the coast 13 adjacent to the sea 12, and uses clean underground seawater as the aquaculture seawater 51. use. That is, the seawater is taken from about 20 meters underground and injected into the culture tank 111 as the seawater 51 for culture. The aquaculture seawater 51 is injected from the water supply port 112 .

Underground seawater is less dependent on temperature and is kept at around 20°C throughout the year. This temperature is suitable for cultivating seaweed. In addition, the underground seawater may contain abundant nutrients necessary for the seedlings 31 to grow.

It is desirable that the depth of the seawater for aquaculture filled in the aquaculture tank 111 is 600 mm or less. More preferably, it is 500 mm or less or 400 mm or less. If the water depth is too deep, the alga bodies (seedlings) in the water cannot be efficiently irradiated with light. Moreover, it becomes difficult to keep the distance between the bottom of the culture tank and the bottom of the paddle within the predetermined range defined by the present invention. On the other hand, if the depth is too shallow, the cultivation efficiency will be poor, so the depth should be at least 50 mm.

The depth of water is set by the height of the drain port 113 . For example, by providing a drain port 113 at a water depth of 500 to 600 mm, the further supplied aquaculture seawater 51 is drained to the outside through the drain port 113, and the water depth in the culture tank 111 is maintained at 500 to 600 mm. . Also, the aquaculture tank may be installed at an angle for irrigation.

As another embodiment, as shown in FIG. 6, clean underground seawater (or water) is once used for terrestrial aquaculture of fish, shellfish, crustaceans, and the like, and the wastewater is used as aquaculture seawater 51 (aquaculture water). may be used. Thereby, nutrient-rich seawater for aquaculture 51 can be obtained.

[Land-based aquaculture method]
The land-based aquaculture method of the present embodiment is performed by the following steps.
<1. Production of seedlings>
As shown in FIG. 7, to produce seedlings 31, mother algae 32 are first collected from the sea 12, and spores 33 are released from the mother algae 32. As shown in FIG. Then, the spores 33 or germinated bodies (not shown) in which the spores 33 have germinated are agglomerated to form seedlings 31 (algal bodies). Agglomeration of the spores 33 or germinated spores 33 can be carried out by the method disclosed in Patent Document 1, for example. In this method, seaweed spores are sown on a plate at a high density of 10 4 or more per 1 cm ² and cultured, and a spore cluster in which a plurality of spores are connected, or a germinated body in which the germinated germinated spores are entwined. After forming clumps, the spore clumps or germinant clumps are peeled off from the plates to obtain seedlings.

<2. Release of seedlings>
Therefore, the aquaculture system of the present embodiment releases the seedlings 31 obtained in this way into the aquaculture seawater 51 contained in the aquaculture tank 111 . Seedlings 31 grow in seawater 51 for aquaculture.

What is necessary for the growth of the seedlings 31 at this time is uniform light irradiation and oxygen supply to the seedlings 31 . In this embodiment, these are realized by the stirrer 201. FIG. This will be discussed later.

<3. Raising seedlings>
(Aquaculture tanks at each stage)
Seedlings 31 grow to about five times their size in a period of about four to five days. Therefore, as shown in FIGS. 8(a) to (d), the size of the culture tank 111 is increased step by step as the seedlings 31 grow. Although FIG. 8 shows only a culture tank with a diameter of 10 meters, culture tanks with a diameter of 11 meters, 12 meters, 14 meters, 15 meters, 16 meters, 18 meters, 20 meters, etc. may be used. For example, Figure 3 is an actual photograph of a 20-meter diameter aquaculture tank. Furthermore, a culture tank with a diameter of 25 meters or a culture tank with a diameter of 30 meters may be used. When the cultivation of a predetermined algae body is completed, the algae body is carried out from the aquaculture tank.

The timing for shifting from one stage to the next is about one week. That is, one stage of the aquaculture process is carried out, and after one week has passed, the next stage of the aquaculture process is carried out.

As shown in FIG. 8(a), in the first stage of the cultivation process, a cultivation tank 111a with a diameter of 1 meter and a size of 0.8 m ² may be used. At this time, the agitator 201 is not used, and the aquaculture seawater 51 is agitated by, for example, an air pump (not shown).

As shown in FIG. 8(b), a culture tank 111b with a diameter of 2 meters and 3.1 m ² may be used in the second stage culture process. At this time, the agitator 201 is not used, and the aquaculture seawater 51 is agitated by, for example, an air pump (not shown).

As shown in FIG. 8(c), a culture tank 111c with a diameter of 5 meters and 19.6 m ² may be used in the third stage culture process. The aquaculture seawater 51 is stirred by the stirrer 201 .

As shown in FIG. 8(d), in the fourth stage cultivation process, a cultivation tank 111d with a diameter of 10 meters and a size of 78.5 m ² may be used. The aquaculture seawater 51 is stirred by the stirrer 201 .

As shown in FIG. 3, in the fifth stage cultivation process, a cultivation tank 111d with a diameter of 20 meters and a size of 314.2 m ² may be used. The aquaculture seawater 51 is stirred by the stirrer 201 . A culture tank with a diameter of 20 meters has four times the area of a culture tank with a diameter of 10 meters, enabling more efficient terrestrial cultivation of algal bodies.

(Length of alga body)
FIG. 9 shows an actual photograph of algal bodies cultured in the present invention. Alga body about 5 mm long, about 13 mm long, about 60 mm long, about 150 mm long, about 320 mm long, and about 680 mm long. be.
This approximately 5 mm algal body was cultivated in an indoor beaker. This approximately 13 mm algal body was cultured in a culture tank with a diameter of 1 m. This approximately 60 mm algal body was cultured in a culture tank with a diameter of 2 m. This approximately 150 mm algal body was cultured in a culture tank with a diameter of 5 m. This approximately 320 mm algal body was cultured in a culture tank with a diameter of 10 m. This approximately 680 mm algal body was cultured in a culture tank with a diameter of 20 m.

In land aquaculture of algal bodies using a substantially circular aquaculture tank and a stirrer as in the present invention, there is a length of algal bodies suitable for aquaculture according to the size of the aquaculture tank. Indoor beakers are suitable for cultivating algal bodies with a length of about 10 mm to 20 mm. For example, an aquaculture tank with a diameter of less than 2 m is suitable for cultivating algal bodies with a length of about 30 mm or less. A culture tank with a diameter of less than 5 m is suitable for culturing algal bodies with a length of about 50 mm or less. A culture tank with a diameter of 5 m or more is suitable for culturing algal bodies with a length of about 50 mm or more. A culture tank with a diameter of 20 m or more is suitable for culturing algal bodies with a length of about 200 mm or more. A culture tank with a diameter of 30 m or more is suitable for culturing algal bodies with a length of about 500 mm or more.

<4. Installation of stirrer>
As described above, in the aquaculture process from the third stage onwards, the aquaculture seawater 51 is agitated by the stirrer 201 (see FIGS. 8(c), (d) and FIG. 3). Therefore, in the aquaculture process from the third stage onwards, the stirrer 201 is installed in the aquaculture seawater 51 contained in the aquaculture tank 111 . It should be noted that different agitators may be used depending on the size of the culture tank.

The stirrer of the present invention is a stirrer having a paddle blade that rotates along the water surface, and the paddle blade has N or more arms extending radially from the center of rotation (where N is 1 or more). natural number), and the arm is provided with a paddle for agitating the aquaculture water. The basic structure of such a stirrer can utilize the existing technology made by the inventor of the present invention (for example, Japanese Patent Application No. 2018-177782, Japanese Patent Application No. 2021-001162). An example is shown below.

(First stirrer)
For example, FIGS. 10 and 11 are examples of the agitator 201. FIG. The stirrer 201 has a structure in which a balancer 231 is rotatably attached between a cylindrical lower housing 211 and an upper housing 212, and a paddle blade 251 is attached to the balancer 231. As shown in FIG.
The lower housing 211 incorporates a motor (not shown) that serves as a drive source for the paddle blades 251 . The upper housing 212 incorporates a motor drive circuit. The motor is housed in the lower housing 211 with its axis of rotation oriented vertically and has its axis of rotation connected to the balancer 231 . The rotation of the motor is decelerated by the deceleration mechanism, transmitted to the balancer 231 , and transmitted to the paddle blades 251 via the balancer 231 .
Incidentally, it is appropriate to rotate the water paddle blade 251 of the present invention at a rotation speed of about 10 seconds to 150 seconds per rotation. Note that this rotation speed is not limited to this, and can be appropriately selected within the scope of the purpose and significance of the present invention. For example, 10 seconds to 20 seconds, 15 seconds to 25 seconds, 20 seconds to 30 seconds, 25 seconds to 35 seconds, 30 seconds to 40 seconds, 35 seconds to 45 seconds, 40 seconds to 50 seconds, 45 seconds to 55 seconds, 50 seconds to 60 seconds, 60 seconds to 70 seconds, 70 seconds to 80 seconds, 80 seconds to 100 seconds, 100 seconds to 120 seconds, or 120 seconds to 150 seconds. Furthermore, it does not have to be a continuous range. For example, these numerical ranges may be combined arbitrarily.

Each part is sealed with a seal (not shown). The seals keep the motor contained in the lower housing 211 and the drive circuit contained in the upper housing 212 watertight. The balancer 231 is connected to a branch pipe 232 branched into three at an angle of 120 degrees. The paddle blade 251 has an arm 252 extending radially from the tip of each of the three branch pipes 232 and a paddle 253 extending downward from the lower end of the arm 252 . Therefore, the paddle blades 251 rotate together with the rotation of the balancer 231 to agitate the fluid (aquaculture water). As shown in FIGS. 8(c), 8(d) and 3, the paddle blades rotate along the water surface in the horizontal plane.

The arm 252 maintains the entire blade on the surface of the water by its buoyancy so that the blade 251 does not sink into the water (see FIGS. 2 and 3). The material of the arm is not particularly limited as long as it is light and strong, but a polyvinyl chloride pipe is suitable.

Balancer 231 also creates buoyancy in the water. The buoyancy of the balancer 231 allows the stirrer 201 to float on water. In the following examples, an example of a stirrer that floats on water will be shown, but the stirrer of the present invention is sufficient if its water paddle blades rotate along the water surface, and it does not have to float on the water surface. do not have. For example, it may be installed on an installation table in a culture tank. In this case, there is no need to float the stirrer on the water surface with a float or the like, so cleaning of the bottom surface of the float and the like is unnecessary, which is preferable.
Also, in the following examples, three arms of the stirrer are shown, but the number of arms is not limited to three unless otherwise specified. When the stirrer is made to float on the surface of the water, it is preferable to have three or more arms because it is easier to balance. For example, as shown in FIGS. 26 and 27, the number of arms may be one or two. 26 and 27, the center of rotation of the paddle blades is positioned at the center of the culture tank, but the center of rotation of the paddle blades may not be positioned at the center of the culture tank.

The stirrer 201 has two connecting rods 271 extending horizontally from the upper housing 212 . These connecting rods 271 are for tying the ropes 301 for fixing the position of the stirrer 201, and have rings 272 at their ends. Rope 301 can be tied to ring 272 .

Such agitation of a culture tank by a stirrer having paddle blades that rotate along the water surface is suitable when a culture tank with a diameter of 5 meters or more is used.

For example, FIGS. 12 and 13 are examples of the agitator 201 as well. This stirrer 201 basically has the same structure as the stirrer 201 described above. What is different is the angle and number of paddles 253 .

Two paddles 253 are attached to each arm 252 at an oblique angle to the radial direction. The oblique angle with respect to the radial direction is, for example, 45 degrees. However, it does not have to be 45 degrees, and other angles may be used.

In any of the agitators 201 described above, the paddle blades 251 rotate when the motor is activated by the drive circuit. The paddle blades 251 rotate along the water surface by the action of the paddles 253 and agitate the aquaculture seawater 51 so as to produce water currents in the vertical and horizontal directions.

(Second stirrer)
The width of the paddle installed on one arm (in the radial direction of the culture tank) is desirably 20% or more and 90% or less of the radius of the culture tank.
A plurality of paddles may be installed on one arm as shown in FIG. In that case, the width of the paddle shall be the sum of the widths of each paddle.
32a and 32b, the width of the paddle is the width of the paddle when viewed from a direction perpendicular to the radial direction of the arm in the plane of rotation of the arm. defined as

(Third Stirrer/Fourth Stirrer): No Paddles FIG. 14 shows a third embodiment of the stirrer 201 (third stirrer). 10 and 11, the same reference numerals denote the same components. FIG. 15 shows a fourth embodiment of the stirrer 201 (fourth stirrer). 12 and 13, the same numerals denote the same components.
In the first and second stirrers, each of the three arms 252 of the paddle 251 is equipped with a paddle 253, whereas in the third and fourth stirrers only one arm is equipped. A paddle 253 is provided.

FIG. 16 is an actual photograph of the third stirrer. The front arm (material: PVC pipe) has paddles along the arm. The back arm (the arm on the left in Fig. 14) does not have a paddle like the arm in front, but it has two self-standing paddles on the bottom of the arm so that it can stand on its own when the water in the culture tank is drained. A plate is provided. FIG. 17 is an enlarged view thereof.

The third agitator and the fourth agitator are suitable for culture tanks with a diameter of 11 meters or more, more preferably for culture tanks with a diameter of 12 meters or more, more preferably for culture tanks with a diameter of 16 meters or more, and more preferably for culture tanks with a diameter of 16 meters or more. It is particularly suitable for aquaculture tanks of 20 meters or more. 3, 16 and 17 use a culture tank with a diameter of 20 meters.

As the size of the culture tank increases, the paddle blades 251 and arms of the agitator also need to be increased in size. If all the arms were provided with paddles as in the past, the stirring resistance would be very large. In order to rotate the paddle blades 251 even with a large stirring resistance, it is necessary to use a motor with a large driving force. However, since a motor with a large driving force is also large in size, if it is installed in an aquaculture tank, the space that can be used for aquaculture will decrease, resulting in inefficiency.

Therefore, instead of providing paddles on all arms like the third and fourth stirrers, paddles are provided only on some arms to suppress stirring resistance, and even a small motor can sufficiently stir the water. The vane 251 may be made rotatable. 14 and 15 are examples in which paddles are provided on only one arm. In this case, the other two arms, which are not provided with paddles, serve to ensure the balance of the paddle blades (agitator). It is also effective to suppress stirring resistance by providing only one arm without a paddle and providing two arms with paddles.
In more general terms, in a stirrer having N or more arms, it is desirable that paddles for stirring aquaculture water are provided only on 1 to N-1 arms. For example, in a three-arm agitator, one or two arms are provided with paddles. In a four-arm agitator, one, two or three arms are provided with paddles.

As the stirring resistance increases, the load on the arm also increases, making it easier to break. If the thickness of the arm is increased so as not to break, the whole paddle blade becomes heavy and cannot be maintained on the water surface. Therefore, the arm of a stirrer used in a large culture tank (a culture tank with a diameter of 15 meters or more) is required to be lighter and stronger. For example, HIVP pipe (thick walled impact resistant PVC pipe) and VU pipe (thin walled PVC pipe) are suitable. When using PVC pipes that are lightweight but have low strength, in order to make up for the lack of strength, the base of the arm is reinforced with a ladder-shaped stainless steel material to prevent breakage, creating a strong stirring arm that is lightweight and has great buoyancy. becomes possible. FIG. 18 shows an example in which the base of the arm is reinforced with a ladder-shaped stainless steel material.

(2) Stirrer installation position 1
The stirrer can be arranged so that the center of rotation of the paddle blades is at the center of the culture tank as shown in FIG. 19a. However, as shown in FIG. can also be placed in The reason is explained below. Here, the predetermined distance is in the range of 7% to 25% of the diameter of the culture tank.

Seaweed grows through photosynthesis. Oxygen released during photosynthesis adheres to the surface of the algal body, which acts as buoyancy. In the natural world, the algal body itself rarely floats on the surface of the water due to the fact that the temporary root attaches to stones, etc. It is necessary to reduce the buoyancy by physically removing oxygen adhering to the surface with a strong stirring force, etc., within the range that does not damage the algae. By continuing to grow while floating on the surface, not only is it not possible to give even light to the green algae in the tank, but the strong light continues to hit the algae, causing the temperature to rise, inhibiting the growth of algae and causing the phenomenon of maturation. Connect.

When the rotation center of the agitator (paddle blade) is set at the center of the aquaculture tank, the center of the water tank overlaps the center of the paddle blade, and the water flow in the center of the tank is stable and cannot be stirred. As a result, the algal bodies are not evenly dispersed and often remain unstirred and mixed. On the other hand, it is desirable to displace the stirrer (paddle blade) from the center of the culture tank by 7% to 25% of the diameter. By shifting the center of the water tank and the center of the agitator, a turbulent flow is generated in the aquaculture tank, and the seaweed (algal body) can be agitated and mixed all over the top, bottom, left, and right.

FIG. 20 illustrates the water flow in the culture tank when the center of rotation of the stirrer (paddle blade) is placed at the center of the culture tank (FIG. 20a) and when it is not placed (FIG. 20b). In Figure 20a, regular water flow is mainly formed by the rotation of the paddle blades. In FIG. 20b, turbulence is generated not only by the rotating flow but also by shifting the rotation center of the stirrer (paddle blade) from the center of the culture tank. Due to this turbulent flow, the seaweed (algal body) can be further stirred and mixed in all directions.

When the center of rotation of the paddle blades of the stirrer is shifted from the center of the culture tank for stirring, it is more preferable to provide the tank with an installation gradient. For example, if the bottom of the aquaculture tank is shaped like a mortar so that the center of the tank is the deepest, seaweed tends to gather in the center, which is not suitable for agitating alga bodies. On the other hand, by tilting the bottom of the culture tank slightly with respect to the horizontal plane, more turbulence is generated in the culture tank, and the seaweed (algal body) can be stirred and mixed all over the top, bottom, left, and right.
The tilt angle is preferably 0.5 degrees or more, more preferably 1 degree or more. If the angle is too large, the agitation of the algal body will be uneven and the installation of the agitator will be more difficult. More preferably, it is 2 degrees or less.

(3) Stirrer installation position 2
The tip of the paddle of the paddle blade of the stirrer (the farthest point from the rotation center of the paddle blade) is desirably within 4 m from the inner wall of the culture tank. That is, it is desirable that the tip of the paddle pass through a place within 4 m from the inner wall of the culture tank when the paddle blade rotates. More preferably within 3 m. More preferably within 2 m. If the tip of the paddle is too far from the inner wall of the culture tank, algae tend to stay between the tip of the paddle and the inner wall of the culture tank. can be greatly suppressed.

In FIG. 21, the stirrer is arranged so that the rotation center of the paddle blades is the center of the culture tank. Paddles are provided on three arms extending in three directions from the center in the figure. A paddle is provided at the tip of the arm in the length direction of the arm. In this figure, the trajectory of the tip of the paddle when the paddle blade rotates is drawn inside the culture tank. The trajectory of the tip of the paddle is arranged in the area surrounded by the dotted line indicating the place 4 m from the inner wall of the culture tank and the inner wall of the culture tank. By arranging them in this way, it is possible to suppress the retention of alga bodies between the paddles and the inner wall of the tank.

In FIG. 22, the center of rotation of the paddle blades is displaced from the center of the culture tank. In this case, not all parts of the trajectory of the tip of the paddle exist in the area surrounded by the dotted line indicating the location 4 m from the inner wall of the culture tank and the inner wall of the culture tank. For example, the solid line portion of the trajectory of the tip of the paddle in FIG. 22 is positioned beyond 4 m from the inner wall of the culture tank. If 50% or more of the trajectory drawn when the tip of the paddle rotates is positioned 4 m from the inner wall of the culture tank, it is possible to suppress the retention of alga bodies between the inner walls of the culture tank. More preferably, it is 60% or more.
At least 50% or more of the trajectory drawn when the tip of the paddle rotates is located within 4 m from the inner wall of the culture tank in the foreground of the photograph in FIG.

In addition, as described above, it is desirable that the center of rotation of the paddle blade is deviated from the center of the culture tank, so it is not always desirable that the entire trajectory of the paddle tip is within 4 m from the inner wall of the culture tank. If the center of rotation of the paddle blades should deviate from the center of the culture tank, it is desirable that 95% or less of the trajectory drawn when the tip of the paddle rotates is located at a distance of 4m from the inner wall of the culture tank. . Then, it is desirable that 50% or more and 95% or less of the trajectory drawn when the tip of the paddle rotates is positioned at a position 4 m from the inner wall of the culture tank.

(4) Insertion and Position Fixing of Stirrer The stirrer 201 is put into the aquaculture seawater 51 accommodated in the aquaculture tank 111 . If the size of the aquaculture tank is 20 m or more in diameter, the paddle blades of the stirrer floating on the water surface will be correspondingly large, making it easier for them to be washed away on the water surface.
For example, in an aquaculture tank with a diameter of 15 m or less, the position of the agitator could be fixed by extending ropes from two stakes as shown in Figures 2 and 24. However, in an aquaculture tank with a diameter of 20 m or more, Since the resistance of the rope is strong, it is necessary to fix the rope from three stakes as shown in Fig.25.
In addition, the agitator used in aquaculture tanks with a diameter of 20 m or more is required to generate a strong water flow, so the load applied to the rope is large. For that reason, we use Dyneema rope, which is strong and does not expand or contract.

<2. Features of the present invention>
The present invention focuses on the concept (distance) of the distance between the bottom of the culture tank and the bottom of the paddle, which has not been particularly considered, and is characterized by setting the distance appropriately to agitate seedlings more efficiently. . The distance between the bottom of the culture tank and the bottom of the paddle is desirably 50 mm or more and 250 mm or less, more preferably 50 mm or more and 200 mm or less.

Figure 28a is a schematic diagram of the present invention. The paddle blades are floating in the culture tank. A paddle blade control part and an arm extending therefrom are suspended on the water surface of the culture tank in the approximate center of the culture tank. A paddle for agitating the culture tank is provided on the arm along the extension direction of the arm. As shown in FIG. 28b, the paddle is defined by the "paddle width", which is the length in the extending direction of the arm, and the "paddle length," which is the length in the water depth direction. The side of the paddle closest to the tank bottom is defined as the paddle bottom. In Figures 28a and 28b, the paddle has a rectangular shape and its base corresponds to the bottom of the paddle. The present invention is characterized in that the interval (distance) between the bottom of the culture tank and the bottom of the paddle is 50 mm or more and 250 mm or less. By narrowing the distance between the bottom of the culture tank and the bottom of the paddle in this manner, the algal bodies between the bottom of the culture tank and the bottom of the paddle are strongly agitated from the direction in which the paddle is propelled toward the inner wall of the culture tank. Unlike the agitation of microalgae, if the space between the bottom of the culture tank and the bottom of the paddle is too wide in the agitation of large alga bodies, the alga bodies cannot be sufficiently agitated even if the seawater can be agitated by the paddles. By setting the distance between the bottom of the culture tank and the bottom of the paddle to 50 mm or more and 250 mm or less, it is possible to stir the algae in the culture tank so as to spread it thinly in the culture tank, and to prevent uneven stirring in the culture tank. (Uneven distribution of algal bodies in the culture tank) is suppressed.

The features of the present invention will be explained using actual measurement data. Figures 29a, 29b, and 29c all show the agitation of algal bodies with a length of about 200 mm in a circular aquaculture tank with a diameter of 24 m. The width of each paddle is 10m. That is, the width of the paddle is 83% of the radius of the culture tank. The vertical width of the paddle is 20 cm. The distance between the culture tank bottom and the paddle bottom is 350 mm in Figure 29a, 200 mm in Figure 29b and 50 mm in Figure 29c. Other conditions are the same in FIGS. 29a, 29b, and 29c. For example, they all use the same algal body and stir. When agitating seaweed in a large culture tank, it is important not only to set the water depth of the culture tank but also to appropriately set the distance between the bottom of the culture tank and the bottom of the paddle.

In Fig. 29a, since the distance between the bottom of the culture tank and the bottom of the paddle is too wide, when the culture tank is viewed from above, the positions of the algal bodies in the culture tank are uneven, and efficient stirring is not possible. I know not. On the other hand, in Figs. 29b and 29c, the distances between the bottom of the culture tank and the bottom of the paddle are 200 mm and 50 mm, respectively, so the distribution of algal bodies in the culture tank is not biased as shown in Fig. 29a. When the seaweed arrangement becomes more biased in plan view, the inconvenience of seaweed wrapping around under other seaweeds increases. When seaweed wraps around other seaweeds, the amount of light irradiation decreases and the growth rate of seaweeds slows down. As a result, the variation in seaweed growth speed in the culture tank increases, making efficient farming difficult. As shown in Figs. 29b and 29c, when the bias in the placement of seaweeds in the culture tank is suppressed, the variation in the amount of light irradiation to each seaweed becomes smaller, so the variation in the seaweed growth rate in the culture tank. is suppressed and efficient aquaculture becomes possible.

Figures 29d, 29e, and 29f all show how algal bodies about 50 mm in length are agitated in a circular aquaculture tank with a diameter of 5 m. The width of each paddle is 1m. That is, the width of the paddle is 40% of the radius of the culture tank. The distance between the culture tank bottom and the paddle bottom is 300 mm in Figure 29d, 200 mm in Figure 29e and 100 mm in Figure 29f. Other conditions are the same in FIGS. 29d, 29e and 29f. For example, they all use the same algal body and stir.
In FIG. 29d, since the gap between the bottom of the culture tank and the bottom of the paddle is wide, the position of the algal body in the culture tank is biased in a plan view when the culture tank is viewed from above, and efficient stirring is not possible. I understand. On the other hand, in FIGS. 29e and 29f, the distances between the bottom of the culture tank and the bottom of the paddle are 200 mm and 100 mm, respectively, so the distribution of the algal bodies in the culture tank is greatly improved from that in FIG. 29d.

The present invention is applicable to aquaculture tanks of various sizes. As shown in the measurement data of Figures 29b and 29c, the effect is particularly remarkable in large culture tanks with a diameter of 11 meters or more. effect.

Arranging the center of rotation of the paddle blades at a position a predetermined distance away from the center of the culture tank further suppresses the bias in the distribution of algal bodies in the plan view in the culture tank. Specifically, the effect becomes remarkable by setting the predetermined distance to a distance of 7% or more and 25% or less of the diameter of the culture tank. Figures 29g to 29j are photographs of actual measurements when alga bodies were stirred in the culture tank with the center of rotation of the paddle blades at a predetermined distance from the center of the culture tank.

In both Figures 29g and 29h, the diameter of the culture tank is 12m, and the distance between the bottom of the culture tank and the bottom of the paddle is 200mm. The length of the algal body in the culture tank is approximately 10 to 15 cm, and the width of the paddle is 53% of the radius of the culture tank. The center of rotation of the paddle blades is located at a predetermined distance from the center of the culture tank. In FIG. 29g, this predetermined distance is 7% of the diameter of the culture tank, and in FIG. 15% of the diameter of the
In both Figures 29i and 29j, the diameter of the culture tank is 12m, and the distance between the bottom of the culture tank and the bottom of the paddle is 250mm. The length of the algal body in the culture tank is approximately 20 to 25 cm, and the width of the paddle is 53% of the radius of the culture tank. The center of rotation of the paddle blades is located at a predetermined distance from the center of the culture tank. In FIG. 29i, this predetermined distance is 7% of the diameter of the culture tank. 15% of the diameter of the
All of the examples of FIGS. 29g to 29i further suppress the imbalance in the distribution of the algal bodies in the culture tank compared to the comparative examples such as FIGS. 29a and 29d.
According to the present invention, the distance between the bottom of the culture tank and the bottom of the paddle is narrowed compared to the conventional example to increase the agitating force of the paddles of the paddle blades. By shifting, the stirring power is synergistically increased. By doing so, as shown in Figs. 29g to 29i, the uneven distribution of alga bodies in the culture tank is further suppressed.

Although the present invention can be applied to alga bodies of various sizes, it is particularly effective in culturing large alga bodies, specifically alga bodies having a length of 50 mm or more. More preferably, the effect is remarkable in aquaculture of algal bodies having a length of 100 mm or more. Due to the weight of the large algae bodies, simply stirring the water in the culture tank tends to cause uneven placement. Because it does.
In the present invention, "the culture tank contains alga bodies with a length of 50 mm or more" means that the length of a certain number of alga bodies in the culture tank is 50 mm or more, and the length of all the alga bodies is 50 mm. It doesn't have to be more. Preferably, 30% or more of the alga bodies in the culture tank are alga bodies having a length of 50 mm or more. More preferably, it accounts for 40% or more, more preferably 50% or more, of algal bodies in the culture tank.

The lateral width of the paddle (the lateral width of the paddle) of the present invention is arbitrary, but a predetermined size is more effective. The width of the paddle of the present invention is desirably 20% or more and 90% or less of the radius of the culture tank. It is more preferably 30% or more and 90% or less, and more preferably 30% or more and 85% or less. For example, if the radius of the culture tank is 10 m, the width of the paddle is preferably 2 m or more and 9 m or less. If the width of the paddle is too small, the narrowed space between the bottom of the culture tank and the bottom of the paddle, which is a feature of the present invention, becomes relatively small, limiting the effects of the present invention. On the other hand, if the paddle width is too large, a large driving force is required to rotate the paddle blades, so it is desirable to avoid making the paddle width longer than necessary.

The vertical width of the paddle of the present invention is arbitrarily set on the premise that the numerical range of the distance between the bottom of the culture tank and the bottom of the paddle specified in the present invention is satisfied, but a predetermined size is more effective. Specifically, the vertical width of the paddle is preferably at least 50 mm or more and 200 mm or less. It is more preferably 50 mm or more and 150 mm or less. If the vertical width of the paddle is too small, the narrowed space between the bottom of the culture tank and the bottom of the paddle, which is a feature of the present invention, becomes relatively small, limiting the effects of the present invention. On the other hand, if the vertical width of the paddle is too large, there is a problem that a large driving force is required to rotate the paddle blades.
Specifically, it is necessary to determine further according to the water depth. For example, if the water depth of the culture tank is 400 mm and the distance between the bottom of the culture tank and the bottom of the paddle is 50 mm or more and 250 mm or less, the vertical width of the paddle must be 150 mm or more and 250 mm or less. More preferably, it is 150 mm or more and 200 mm or less.
This estimate is for the case where the paddle arm is floating on the water surface of the culture tank and the paddle is positioned just below the water surface. If the paddle is not positioned below the water surface, such as when the arm is slightly below the water surface, the distance between the paddle and the water surface is adjusted. For example, if the paddle is placed 3 cm below the surface of the water, the vertical width of the paddle should be 147 mm or more and 247 mm or less.

The rotational speed of the paddle blades is appropriately selected according to the distance between the bottom of the culture tank and the bottom of the paddle, the size of the culture tank, the size of the alga bodies to be cultured, and the like. If the distance between the bottom of the culture tank and the bottom of the paddle is not set appropriately, it is possible to suppress the uneven distribution of algal bodies in the culture tank to some extent by setting the rotational speed of the paddle blades well. be. However, if the distance between the bottom of the culture tank and the bottom of the paddle is appropriately set as in the present invention, the rotational speed of the paddle blades can be set broadly.
It is desirable to rotate the water paddle blades at a rotational speed of about 10 to 150 seconds per rotation. Especially when stirring large alga bodies, if the speed is too high, the alga bodies will be torn apart. , the stirring efficiency and the aquaculture efficiency deteriorate.

Here, FIG. 23 shows the preferred situation of the present invention described so far.
Furthermore, the effect is remarkable in aquaculture of alga bodies having a length of 50 mm or more. Furthermore, it is desirable that the width of the paddle is 20% or more and 90% or less of the radius of the culture tank.

Furthermore, examples of variations of the present invention are shown.
The surface shape of the paddle may be any shape as long as it can agitate the culture tank. Here, the surface profile means the profile in a plane perpendicular to the arm rotation direction (and the water surface). Although the surface shape is rectangular in FIGS. 28a and 28b, other shapes may be used. For example, as shown in FIGS. 30a and 30b, a shape in which rectangles of different sizes are combined or a shape in which rectangles and triangles are combined may be used.
In the present invention, "average paddle vertical width = surface area of paddle/paddle horizontal width"
defines the average paddle line width defined by
If the paddle shape is not rectangular as shown in FIGS. 30a and 30b, define a virtual rectangle (or square) defined by the paddle width and average paddle height as shown in the right side of FIGS. 30a and 30b, The distance between the bottom of the rectangle and the bottom of the culture tank is defined as "the distance between the bottom of the culture tank and the bottom of the paddle".

A plurality of paddles may be provided on each arm. FIG. 31 shows an example in which one arm is provided with three paddles. In this case, the sum of the paddle widths is the paddle width of the arm.

Also, the paddles may be provided so as to be inclined with respect to the extending direction of the arm as shown in FIG. In that case, as shown in FIGS. 33a and 33b, the lateral width of the paddle is defined in a shape obtained by projecting the paddle surface onto a vertical plane including the arm. When there are a plurality of paddles as shown in FIG. 33b, the sum of the paddle widths defines the paddle width of each arm.

In addition, the present invention can apply various variations shown in the above "1. Background of the present invention (variations)".
For example, the paddle blades can be rotated at a rotational speed of, for example, about 10 to 150 seconds per rotation.
For example, the stirrer can be arranged so that the center of rotation of the paddle blades is the center of the culture tank as shown in FIG. 19a. It can also be placed at a predetermined distance from the center of the
For example, one or more arms extending radially from the center of rotation are sufficient for the paddle blades, but three or four or more arms are suitable for floating the paddle springs on the water surface.
For example, instead of providing paddles on all arms, paddles may be provided only on some arms to suppress stirring resistance, so that even a small motor can sufficiently rotate the paddle blades.

11 Aquaculture facility 12 Sea 13 Coast 31 Seedling 32 Mother algae 51 Seawater for aquaculture 101 Terrestrial aquaculture apparatus 111 Aquaculture tank 111a Aquaculture tank (aquaculture tank with a diameter of 1 meter)
111b Aquaculture tank (aquaculture tank with a diameter of 2 meters)
111c Aquaculture tank (aquaculture tank with a diameter of 5 meters)
111d Aquaculture tank (aquaculture tank with a diameter of 10 meters)
112 Water supply port 113 Drain port 201 Stirrer 211 Lower housing 212 Upper housing 231 Balancer 232 Branch pipe 251 Web blade 252 Arm 253 Paddle 271 Connecting rod 272 Ring 301 Rope 302 Pile G Ground

Claims (7)

In a land-based aquaculture apparatus for algae, the aquaculture tank is equipped with aquaculture water and a stirrer having paddle blades that rotate along the surface of the water.
The culture tank has a diameter of 5 m or more,
The water depth of the culture tank is 100 mm or more and 600 mm or less ,
The rotation speed of the paddle blade is 10 seconds to 150 seconds per rotation ,
including algal bodies with a length of 50 mm or more in the culture tank,
The paddle blade has N or more arms extending radially from the center of rotation (where N is a natural number of 1 or more), and the arms are provided with paddles for agitating the aquaculture water,
The width of the paddle is 20% or more and 90% or less of the radius of the culture tank,
A land-based aquaculture apparatus for algal bodies, wherein the distance between the bottom of the aquaculture tank and the bottom of the paddle is 50 mm or more and 250 mm or less. 2. The land-based aquaculture apparatus for algal bodies according to claim 1, wherein the distance between the bottom of the aquaculture tank and the bottom of the paddle is 50 mm or more and 200 mm or less. 3. The land-based aquaculture apparatus for algal bodies according to claim 1 or 2, wherein the aquaculture tank has a diameter of 11 m or more. 4. The land-based aquaculture apparatus for algal bodies according to claim 1, wherein the shape of the aquaculture tank is substantially circular, polygonal or elliptical. The center of rotation of the paddle blades is arranged at a predetermined distance from the center of the culture tank, and the predetermined distance is 7% or more and 25% or less of the diameter of the culture tank. The land-based aquaculture apparatus for algal bodies according to any one of claims 1 to 4. In a method for cultivating algal bodies on land, the method comprises a culture tank containing culture water and an agitator having paddle blades that rotate along the water surface,
The culture tank has a diameter of 5 m or more,
The water depth of the culture tank is 100 mm or more and 600 mm or less ,
The rotation speed of the paddle blade is 10 seconds to 150 seconds per rotation ,
including algal bodies with a length of 50 mm or more in the culture tank,
The paddle blade has N or more arms extending radially from the center of rotation (where N is a natural number of 1 or more), and the arms are provided with paddles for agitating the aquaculture water,
The width of the paddle is 20% or more and 90% or less of the radius of the culture tank,
A method for cultivating algal bodies on land, wherein the distance between the bottom of the culture tank and the bottom of the paddle is 50 mm or more and 250 mm or less. The center of rotation of the paddle blades is arranged at a predetermined distance from the center of the culture tank, and the predetermined distance is 7% or more and 25% or less of the diameter of the culture tank. The land-based algal culture method according to claim 6.

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