Algae cultivation device

Abstract

To provide an algae growth device that can automatically transfer algae from a growth tank, according to the growth level of the algae.SOLUTION: An algae growth device 1 has a growth tank 10 for growing algae, an algae transfer device 40 for transferring algae from the growth tank 10, an imaging device 50 for capturing the algae in the growth tank 10, and a control device 60 for operating the algae transfer device 40 on the basis of the result of capturing by the imaging device 50.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an algae cultivation device.

Background Art

[0002] Conventionally, algae cultivation devices for cultivating algae such as nori, wakame, and kelp on land have been known. The algae cultivation device of Patent Document 1 below includes a gas dissolution unit capable of generating a dissolution solution in which carbon dioxide is dissolved in a liquid, an algae tank capable of storing the dissolution solution and the algae placed in the dissolution solution, and a light emitter capable of emitting light toward the inside of the algae tank in which the dissolution solution and the algae are stored.

[0003] Further, the marine plant cultivation system of Patent Document 2 below includes a pumping channel for pumping up salt water from at least one water source of submarine groundwater and deep ocean water, a gas mixing unit for mixing a gas containing carbon dioxide with the salt water to generate a mixed salt water, a growth tank for storing the mixed salt water and capable of accommodating algae, and a light irradiation unit for irradiating the growth tank with light.

[0004] The growth tank of Patent Document 2 below has a plurality of cultivation chambers connected in order of increasing volume from the upstream side to the downstream side. Between adjacent growth chambers, there is a communication port that can be made liquid-permeable by opening and closing, and marine organisms growing in the upstream growth chamber are led to and grown in the adjacent downstream growth chamber according to the growth stage of the marine organisms.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, when cultivating algae in a single cultivation tank as in Patent Document 1 above, since the cultivation environment is unified, it is difficult to perform cultivation according to the degree of algae cultivation. In addition, as the cultivation of algae progresses, there is a concern that the amount of light required for photosynthesis becomes insufficient due to the concentration of algae in the cultivation tank. Therefore, there are significant problems in promoting industrialization.

[0007] Also, when cultivating algae in a plurality of cultivation tanks as in Patent Document 2 above, it is possible to avoid the concentration due to the cultivation of algae. However, on the other hand, there is a problem in grasping the degree of algae cultivation, which is the key timing for transferring the cultivation tank. Conventionally, the degree of algae cultivation has been determined by once taking out the algae and measuring the wet weight of the algae including the cultivation water, but this increases the number of steps and is inefficient.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide an algae cultivation apparatus capable of automatically transferring algae from a cultivation tank according to the degree of algae cultivation.

Means for Solving the Problems

[0009] An algae cultivation apparatus according to an aspect of the present invention includes a cultivation tank for cultivating algae, an algae transfer device for transferring the algae from the cultivation tank, a photographing device for photographing the algae in the cultivation tank, and a control device for operating the algae transfer device based on a photographing result of the photographing device.

[0010] Further, in the algae cultivation apparatus according to an aspect of the present invention, the control device may determine the degree of algae cultivation based on the size of the algae photographed by the photographing device.

[0011] Further, in the algae cultivation apparatus according to an aspect of the present invention, a second cultivation tank having a larger volume than the cultivation tank is provided, and when the degree of algae cultivation exceeds a predetermined threshold, the control device operates the algae transfer device to transfer the algae from the cultivation tank to the second cultivation tank.

[0012] Further, in the algae cultivation device according to one aspect of the present invention, the control device may determine the presence or absence of a disease of the algae based on the color of the algae photographed by the photographing device.

[0013] Further, in the algae cultivation device according to one aspect of the present invention, the device includes a waste tank for discarding the algae, and when the color development range of a predetermined color of the algae exceeds a predetermined threshold value, the control device may operate the algae transfer device to transfer the algae from the cultivation tank to the waste tank.

[0014] Further, in the algae cultivation device according to one aspect of the present invention, the cultivation tank may include cultivation water for cultivating the algae, and a measuring device for measuring a state quantity of the cultivation water.

[0015] Further, in the algae cultivation device according to one aspect of the present invention, the measuring device may include at least one of a pH detector, a carbon dioxide dissolution detector, and a liquid analysis device.

Advantages of the Invention

[0016] According to one aspect of the present invention described above, it is possible to provide an algae cultivation device capable of automatically transferring algae from a cultivation tank according to the degree of algae cultivation.

Brief Description of the Drawings

[0017]

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Embodiments for Carrying Out the Invention

[0018] Hereinafter, the algae cultivation device according to the embodiment of the present invention will be described in detail with reference to the drawings. Hereinafter, first, the outline of the embodiment of the present invention will be described, and then the details of the embodiment of the present invention will be described.

[0019] 〔Outline〕 In an algae cultivation device for cultivating algae on land, it is important to grasp the degree of algae growth, control diatoms and the like that inhibit algae growth, and manage the environment necessary for algae growth, specifically, water quality (nutrient salts, dissolved carbon dioxide), water temperature, and illuminance.

[0020] The algae cultivation device shown in Patent Document 1 is composed of a gas dissolution part for carbon dioxide (CO2), an algae cultivation tank, lighting, a circulation pump, and a supply part for components necessary for cultivation such as nutrient salts. There is also a pipe for sending water from the gas dissolution part to the cultivation tank. The cultivation water is adjusted in the gas dissolution part and the supply part, sent to and circulated in the algae cultivation tank, and the seaweed to be cultivated is cultivated.

[0021] The marine plant cultivation system shown in Patent Document 2 divides the cultivation room according to the cultivation stage of the algae. This cultivation system supplies the cultivation water to each cultivation room through individual pipes and moves it to a larger cultivation room according to the cultivation stage of the algae. According to this configuration, since the cultivation water is independent for each cultivation room, the components of the cultivation water can be changed according to the cultivation stage, and it is possible to efficiently supply the cultivation components to the algae.

[0022] In the conventional algae cultivation device, roughly speaking, there are two methods: one is to cultivate in a single cultivation tank as in Patent Document 1, and the other is to change the cultivation tank according to the growth degree of the algae as in Patent Document 2. In the method of cultivating in a single cultivation tank, since the cultivation environment is unified, it is difficult to cultivate according to the cultivation situation. In addition, as the cultivation of seaweed progresses, there is a concern that the LED lighting necessary for photosynthesis becomes insufficient due to the concentration of algae in the cultivation tank. Therefore, there are significant problems in promoting industrialization. Also, in the method of changing the cultivation tank according to the growth degree of the algae, it is possible to avoid the concentration caused by the cultivation of the algae. However, on the other hand, there is a problem in grasping the growth degree, which is the key to the timing of moving the cultivation room. The conventional method of measuring the growth degree is to judge by taking out the algae once and measuring the wet weight in a state where the algae contains seawater, but the process increases and it is inefficient.

[0023] In an embodiment of the present invention, in an algae cultivation apparatus, algae in a cultivation tank are photographed by a photographing device, and based on the image data acquired by the photographing device, the cultivation degree of the algae is easily grasped. As a result, the process of measuring the wet weight of algae as in the prior art is reduced, and at the same time, it becomes possible to transfer the algae according to the cultivation degree of the algae, stabilize the arrival of light necessary for the photosynthesis of the algae, and as a result, it becomes possible to cultivate the algae with high efficiency. In addition, by analyzing the image data acquired by the photographing device, it is possible to grasp diseases caused by pathogenic microorganisms, such as "white rot disease" and "red rot disease", which are diseases of seaweed. Therefore, it is also possible to reduce the loss cost by early detection of the disease.

[0024] 〔First Embodiment〕 FIG. 1 is a configuration diagram of an algae cultivation apparatus 1 according to the first embodiment. As shown in FIG. 1, the algae cultivation apparatus 1 includes a plurality of cultivation tanks 10, an ultraviolet sterilization tank 20, a waste tank 30, an algae transfer device 40, a photographing device 50, and a control device 60.

[0025] The cultivation tank 10 houses algae and cultivation water for cultivating the algae. The algae are, for example, seaweed, wakame, kelp, etc. The cultivation water is, for example, salt water containing nutrients with carbon dioxide dissolved therein. In this cultivation tank 10, a water flow generating device including a pump or the like that gives a flow to the cultivation water in the tank, a light irradiation device including an LED (light emitting diode) that irradiates light for the algae to perform photosynthesis in the tank, and the like are provided.

[0026] The algae cultivation apparatus 1 includes a first cultivation tank 11, a second cultivation tank 12, and a third cultivation tank 13 as the cultivation tank 10. The second cultivation tank 12 has a larger volume than the first cultivation tank 11. Also, the third cultivation tank 13 has a larger volume than the second cultivation tank 12. For example, the second cultivation tank 12 may have a volume twice that of the first cultivation tank 11. Also, for example, the third cultivation tank 13 may have a volume four times that of the first cultivation tank 11 (twice that of the second cultivation tank 12). Note that the algae cultivation apparatus 1 of the present embodiment includes three stages of cultivation tanks 10, but the number of stages is arbitrary, and it may have two stages or four or more stages of cultivation tanks 10.

[0027] The algae transfer device 40 includes a first transfer line 41 for transferring algae from the first cultivation tank 11 to the second cultivation tank 12. The first transfer line 41 is a pipe section connecting between the first cultivation tank 11 and the second cultivation tank 12, and an on-off valve 41a is provided in the pipe section. Further, the algae transfer device 40 includes a second transfer line 42 for transferring algae from the second cultivation tank 12 to the third cultivation tank 13. The second transfer line 42 is a pipe section connecting between the second cultivation tank 12 and the third cultivation tank 13, and an on-off valve 42a is provided in the pipe section.

[0028] In addition, the algae transfer device 40 includes a third transfer line 43 for transferring algae from the first cultivation tank 11 to the ultraviolet sterilization tank 20. The third transfer line 43 is a pipe section connecting between the first cultivation tank 11 and the ultraviolet sterilization tank 20, and an on-off valve 43a and a pump 43b are provided in the pipe section. Further, the algae transfer device 40 includes a fourth transfer line 44 for transferring (returning) algae from the ultraviolet sterilization tank 20 to the first cultivation tank 11. The fourth transfer line 44 is a pipe section connecting between the ultraviolet sterilization tank 20 and the first cultivation tank 11, and an on-off valve 44a is provided in the pipe section.

[0029] In addition, the algae transfer device 40 includes a fifth transfer line 45 for transferring algae from the second cultivation tank 12 to the ultraviolet sterilization tank 20. The fifth transfer line 45 is a pipe section connecting between the second cultivation tank 12 and the ultraviolet sterilization tank 20, and an on-off valve 45a and a pump 45b are provided in the pipe section. Further, the algae transfer device 40 includes a sixth transfer line 46 for transferring (returning) algae from the ultraviolet sterilization tank 20 to the second cultivation tank 12. The sixth transfer line 46 is a pipe section connecting between the ultraviolet sterilization tank 20 and the second cultivation tank 12, and an on-off valve 46a is provided in the pipe section.

[0030] In addition, the algae transfer device 40 includes a seventh transfer line 47 for transferring algae from the third cultivation tank 13 to the ultraviolet sterilization tank 20. The seventh transfer line 47 is a pipe section connecting between the third cultivation tank 13 and the ultraviolet sterilization tank 20, and an on-off valve 47a and a pump 47b are provided in the pipe section. Further, the algae transfer device 40 includes an eighth transfer line 48 for transferring (returning) algae from the ultraviolet sterilization tank 20 to the third cultivation tank 13. The eighth transfer line 48 is a pipe section connecting between the ultraviolet sterilization tank 20 and the third cultivation tank 13, and an on-off valve 48a is provided in the pipe section.

[0031] In addition, the algae transfer device 40 includes a ninth transfer line 49 for transferring algae from the ultraviolet sterilization tank 20 to the waste tank 30. The ninth transfer line 49 is a pipe section connecting between the ultraviolet sterilization tank 20 and the waste tank 30, and an on-off valve 49a is provided in the pipe section. The above-described on-off valves 41a to 49a are electric valves, solenoid valves, etc., and together with the pumps 43b, 45b, 48b, they are operated under the control of the control device 60.

[0032] In this embodiment, the second cultivation tank 12 is provided at a position lower than the first cultivation tank 11, the third cultivation tank 13 is provided at a position lower than the second cultivation tank 12, the ultraviolet sterilization tank 20 is provided at a position higher than the first cultivation tank 11, the second cultivation tank 12, and the third cultivation tank 13, and the waste tank 30 is provided at a position lower than the ultraviolet sterilization tank 20. In this case, the pumps 43b, 45b, 48b only need to be operated when pumping algae and cultivation water from the first cultivation tank 11, the second cultivation tank 12, and the third cultivation tank 13 to the ultraviolet sterilization tank 20. For transfers between other tanks, it is only necessary to open the on-off valves 41a to 49a using the head difference. In the case where each tank is provided at the same height, pumps may be provided in each of the transfer lines 41 to 49.

[0033] Figure 2 is a configuration diagram of the ultraviolet sterilization tank 20 according to the first embodiment. In FIG. 2, the connection relationship between the ultraviolet sterilization tank 20 and the first cultivation tank 11 is shown, but the connection relationships between the ultraviolet sterilization tank 20 and the second cultivation tank 12 and between the ultraviolet sterilization tank 20 and the third cultivation tank 13 have the same configuration. As shown in FIG. 2, the ultraviolet sterilization tank 20 includes a net member 21, an ultraviolet light source 22, a cultivation water transfer device 23, a lower water level gauge 24, an upper water level gauge 25, and a moving device 26.

[0034] The ultraviolet sterilization tank 20, the net member 21, the ultraviolet light source 22, the cultivation water transfer device 23, the lower water level gauge 24, the upper water level gauge 25, and the moving device 26 constitute an ultraviolet sterilization device 2 that exposes algae to ultraviolet light by drying them out of the cultivation water. The ultraviolet sterilization device 2 simulates the ebb and flow of seawater in nature and the drying-out process by ultraviolet light from sunlight, and prevents the growth of algae due to the attachment of diatoms by irradiating with ultraviolet light.

[0035] The interior of the ultraviolet sterilization tank 20 is divided into an upper space and a lower space by the net member 21. The above-described third transfer line 43, fourth transfer line 44, and ninth transfer line 49 are connected to the upper space of the ultraviolet sterilization tank 20. The net member 21 has a mesh smaller than the average size of the larvae of the algae, captures the algae received from the third transfer line 43 with the mesh, and separates the cultivation water (indicated by reference numeral 3 in FIG. 2) from the algae.

[0036] The ultraviolet light source 22 irradiates the algae supported by the net member 21 with ultraviolet light. The ultraviolet light source 22 includes, for example, an ultraviolet light-emitting diode capable of irradiating ultraviolet light equivalent to UV-B (ultraviolet B wave) having a wavelength of 280 to 320 nm. The ultraviolet light source 22 inactivates diatoms and the like attached to the algae by irradiating the algae supported by the net member 21 with ultraviolet light for a certain period of time.

[0037] The moving device 26 includes a guide and an actuator for moving the net member 21 up and down, and adjusts the exposure of the algae to ultraviolet light by moving the net member 21 closer to and farther from the ultraviolet light source 22. The breeding water transfer device 23 includes a water removal line 23a, a water removal valve 23b, a buffer tank 23c, a return water line 23d, a return water valve 23e, a pump 23f, a water sampling line 23g, a water sampling valve 23h, and a breeding water extraction part 23i.

[0038] The water removal line 23a is a pipe section connecting between the ultraviolet sterilization tank 20 and the buffer tank 23c, and a water removal valve 23b (on-off valve) is provided in the pipe section. The buffer tank 23c stores the breeding water transferred from the ultraviolet sterilization tank 20 through the water removal line 23a. The return water line 23d is a pipe section connecting between the buffer tank 23c and the downstream side of the on-off valve 43a of the third transfer line 43, and a return water valve 23e (on-off valve) and a pump 23f are provided in the pipe section.

[0039] The water sampling line 23g is a pipe section connecting between the water removal valve 23b of the water removal line 23a and the buffer tank 23c and the breeding water extraction part 23i, and a water sampling valve 23h (on-off valve) is provided in the pipe section. The breeding water extraction part 23i is provided for the user to extract a part of the breeding water outside the device to check the state of the breeding water. The above-mentioned water removal valve 23b, return water valve 23e, and water sampling valve 23h are electric valves, solenoid valves, etc., and together with the pump 23f, they are operated under the control of the control device 60.

[0040] The lower water level gauge 24 detects that the water level of the breeding water in the ultraviolet sterilization tank 20 is lower than the net member 21. This lower water level gauge 24 is arranged above the connection position of the water removal line 23a in the lower space of the ultraviolet sterilization tank 20. The upper water level gauge 25 detects that the water level of the breeding water in the ultraviolet sterilization tank 20 is higher than the net member 21. This upper water level gauge 25 is arranged above the connection position of the fourth transfer line 44 in the upper space of the ultraviolet sterilization tank 20. The above-mentioned lower water level gauge 24 and upper water level gauge 25 are connected to the control device 60.

[0041] The cultivation water transfer device 23 with the above configuration operates under the control of the control device 60. For example, when receiving algae and cultivation water from the third transfer line 43 into the ultraviolet sterilization tank 20 and separating the cultivation water from the algae by the mesh member 21, the cultivation water transfer device 23 opens the drainage valve 23b of the drainage line 23a to lower the water level of the cultivation water in the ultraviolet sterilization tank 20 below the mesh member 21.

[0042] Also, after ultraviolet irradiation, the cultivation water transfer device 23 opens the return water valve 23e of the return water line 23d, operates the pump 23f, and returns the cultivation water stored in the buffer tank 23c to the ultraviolet sterilization tank 20 to raise the water level of the cultivation water in the ultraviolet sterilization tank 20 above the mesh member 21. Thereby, the algae can be transferred (returned) from the ultraviolet sterilization tank 20 to the first cultivation tank 11 via the fourth transfer line 44.

[0043] Returning to FIG. 1, a photographing device 50 is provided in each of the plurality of cultivation tanks 10. The photographing device 50 is fixedly positioned at a fixed point in each cultivation tank 10 to photograph the algae. Also, a measuring device 51 for measuring the state quantity of the cultivation water is provided in each of the plurality of cultivation tanks 10. The measuring device 51 includes at least one of a pH detector, a carbon dioxide dissolution detector, and a liquid analysis device. Note that the measuring device 51 may include a thermometer, a flow meter, an illuminometer, and other sensors. Each of the above-described photographing devices 50 and each measuring device 51 are connected to the control device 60.

[0044] The control device 60 includes a data processing unit 61 that processes various data input from the imaging device 50, the measurement device 51, the lower water level gauge 24, the upper water level gauge 25, etc., and a device control unit 62 that controls the operations of various devices provided in the cultivation tank 10, the ultraviolet sterilization tank 20, and the algae transfer device 40. The control device 60 is configured such that an arithmetic unit such as a CPU (not shown), a storage unit such as a RAM, a ROM, a hard disk drive (HDD), and a solid state drive (SSD), and an input / output interface for data exchange with each component device are connected by a bus (not shown). In addition to the above-described component devices, a display device such as a display (not shown) and an input device such as a mouse and a keyboard are connected to the input / output interface.

[0045] The storage unit stores a program for the arithmetic unit to read and execute, and the control device 60 executes the determination of the growth degree of the algae, the determination of the presence or absence of algae diseases, the transfer of the algae based on these determinations, and the sterilization treatment of the algae, which will be described below, according to the program. Specifically, the control device 60 determines the growth degree of the algae and the presence or absence of algae diseases based on the imaging result of the imaging device 50, and also executes the sterilization treatment of the algae every predetermined time.

[0046] FIG. 3 is a flowchart for explaining the transfer process of the algae from the first cultivation tank 11 to the second cultivation tank 12 in the algae cultivation device 1 according to the first embodiment. Note that FIG. 3 shows the flow of transferring the algae from the first cultivation tank 11 to the second cultivation tank 12, but the flow of transferring the algae from the second cultivation tank 12 to the third cultivation tank 13 is the same. As shown in FIG. 3, first, the control device 60 starts counting the time ts (step S1). The time ts is the residence time of the algae in the first cultivation tank 11.

[0047] Next, the control device 60 determines whether the time ts has reached a predetermined time (Check time) (step S2). The predetermined time is the cycle time for the control device 60 to determine the growth degree of the algae and the presence or absence of algae diseases. Note that the cycle time may be set to a fixed time such as 1 hour, for example, or may be appropriately changed according to the growth rate of the algae.

[0048] When the time ts reaches the predetermined time (when step S2 is "YES"), the control device 60 operates the imaging device 50, acquires image data of the algae, and performs image processing on the image data (step S3). For example, the control device 60 acquires 10 pieces of image data taken 10 times by the imaging device 50 at an interval of 1 frame.

[0049] Next, the control device 60 determines the presence or absence of algae diseases based on the image data (step S4). Specifically, the control device 60 determines the presence or absence of algae diseases by calculating the color development (white, red, etc.) range due to algae diseases. For example, the control device 60 quantifies the area for each color of the image data and obtains its distribution. Then, a threshold value for determining the occurrence of each disease is set, and the control device 60 determines that a disease has occurred in the algae when the area of a specific color determined to be a disease exceeds the threshold value.

[0050] When it is determined that a disease has occurred in the algae (when step S4 is "present"), the control device 60 interrupts the growth of the algae. When the color development range of a predetermined color of the algae exceeds a predetermined threshold value, the control device 60 operates the algae transfer device 40 and transfers the algae from the first cultivation tank 11 (through the ultraviolet sterilization tank 20 in this embodiment) to the waste tank 30. Then, the algae in which the disease has occurred are discarded in the waste tank 30.

[0051] When it is determined that no disease has occurred in the algae (when step S4 is "absent"), the control device 60 determines whether the size of the algae (Size(ts)) at the time ts is larger than a predetermined size (Check size) based on the image data (step S5). The predetermined size is the maximum size of the algae determined for each cultivation tank 10.

[0052] The control device 60, for example, binarizes the image data acquired by the imaging device 50 and calculates the surface area of the portion having the color of the algae. Then, a threshold value is set based on the correlation between the surface area and weight of the algae acquired in advance. The control device 60 calculates the surface area of the portion having the color of the algae for each image data, and determines that the algae has exceeded the maximum size determined for each cultivation tank 10 when the average value exceeds the threshold value.

[0053] When it is determined that the algae has not exceeded the maximum size determined for each cultivation tank 10 (when step S5 is "NO"), the process returns to step S1, and the control device 60 restarts the count of the time ts. On the other hand, when it is determined that the algae has exceeded the maximum size determined for each cultivation tank 10 (when step S5 is "YES"), the control device 60 opens the on-off valve 41a of the first transfer line 41 (step S6). Thus, the transfer of the algae from the first cultivation tank 11 to the second cultivation tank 12 is completed.

[0054] FIG. 4 is a flowchart for explaining the transfer process of the algae from the first cultivation tank 11 to the ultraviolet sterilization tank 20 in the algae cultivation apparatus 1 according to the first embodiment. In FIG. 4, although the flow of transferring the algae from the first cultivation tank 11 to the ultraviolet sterilization tank 20 is shown, the flows of transferring the algae from the second cultivation tank 12 to the ultraviolet sterilization tank 20 and from the third cultivation tank 13 to the ultraviolet sterilization tank 20 are the same. As shown in FIG. 4, first, the control device 60 starts counting the time tuv (step S11). The time tuv is the residence time of the algae in the first cultivation tank 11.

[0055] Next, the control device 60 determines whether the time ts has reached a predetermined time (Uv time) (step S12). The predetermined time is the cycle time for sterilizing the algae. Note that the cycle time may be set to a fixed time such as 12 hours and 25 minutes in accordance with the cycle of the natural ebb tide, for example, or may be appropriately changed according to the growth rate of the algae.

[0056] When the time tuv reaches a predetermined time (when step S12 is "YES"), the control device 60 opens the on-off valve 43a of the third transfer line 43 (step S13) and operates the pump 43b of the third transfer line 43 (step S14). As described above, the transfer of algae from the first cultivation tank 11 to the ultraviolet sterilization tank 20 is completed.

[0057] FIGS. 5 and 6 are flowcharts for explaining the sterilization process of algae in the algae cultivation apparatus 1 according to the first embodiment. Note that the circled reference numeral 1 shown in FIGS. 4 and 5 indicates the connection between the two flows. When the transfer of algae from the first cultivation tank 11 to the ultraviolet sterilization tank 20 is completed, the control device 60 closes the on-off valve 43a of the third transfer line 43 (step S21) and stops the pump 43b of the third transfer line 43 (step S22) as shown in FIG. 5.

[0058] Next, the control device 60 opens the drainage valve 23b of the drainage line 23a connected to the ultraviolet sterilization tank 20 (step S23) and operates the pump 23f (step S24). Here, when it is necessary to collect the cultivation water for the user to check the state of the cultivation water (when step S25 is "YES"), the control device 60 opens the water sampling valve 23h of the water sampling line 23g (step S26). After opening the water sampling valve 23h of the water sampling line 23g and extracting a part of the cultivation water at the cultivation water extraction section 23i, the control device 60 closes the water sampling valve 23h of the water sampling line 23g (step S27).

[0059] Next, the control device 60 checks whether the water level of the cultivation water in the ultraviolet sterilization tank 20 is lower than the net member 21 by the lower water level gauge 24 (step S28). When the water level of the cultivation water in the ultraviolet sterilization tank 20 is lower than the net member 21 (when step S28 is "YES"), the control device 60 stops the pump 23f (step S29) and closes the drainage valve 23b of the drainage line 23a (step S30).

[0060] Next, the control device 60 operates the moving device 26 to adjust the height of the net member 21 supporting the algae (step S31). Then, the control device 60 irradiates the algae with ultraviolet rays from the ultraviolet light source 22 (step S32). Next, the control device 60 checks whether the irradiation time of the ultraviolet rays has reached a preset irradiation time (step S33). When the irradiation time of the ultraviolet rays reaches the preset irradiation time (when step S33 is "YES"), the control device 60 stops the ultraviolet ray irradiation of the ultraviolet light source 22 (step S34).

[0061] After stopping the ultraviolet ray irradiation of the ultraviolet light source 22, as shown in FIG. 6, the control device 60 returns the height of the net member 21 supporting the algae to the initial position (step S41). Next, the control device 60 opens the return water valve 23e of the return water line 23d (step S42) and operates the pump 23f (step S43). Then, the control device 60 checks, using the upper water level gauge 25, whether the water level of the cultivation water in the ultraviolet sterilization tank 20 is higher than the net member 21 (step S44).

[0062] When the water level of the cultivation water in the ultraviolet sterilization tank 20 is higher than the net member 21 (when step S44 is "YES"), the control device 60 stops the pump 23f (step S45), closes the return water valve 23e of the return water line 23d (step S46). Then, the control device 60 opens the on-off valve 44a of the fourth transfer line 44 (step S47). Thus, the return of the algae from the ultraviolet sterilization tank 20 to the first cultivation tank 11 is completed.

[0063] As described above, the algae cultivation device 1 according to the present embodiment includes a cultivation tank 10 for cultivating algae, an algae transfer device 40 for transferring algae from the cultivation tank 10, a photographing device 50 for photographing the algae in the cultivation tank 10, and a control device 60 for operating the algae transfer device 40 based on the photographing result of the photographing device 50. According to this configuration, the algae can be automatically transferred from the cultivation tank 10 according to the degree of algae cultivation.

[0064] In addition, in the algae cultivation device 1 according to the present embodiment, the control device 60 determines the growth degree of the algae based on the size of the algae photographed by the photographing device 50. According to this configuration, by simply grasping the growth degree of the algae from the size of the algae photographed by the photographing device 50, the process of measuring the wet weight of the algae as in the conventional type is reduced. At the same time, by grasping the growth degree of the algae, it becomes possible to set a cultivation environment suitable for cultivation, and as a result, high-speed cultivation of algae can be achieved.

[0065] In addition, the algae cultivation device 1 according to the present embodiment includes a second cultivation tank 12 (second cultivation tank) having a larger volume than the first cultivation tank 11. When the growth degree of the algae exceeds a predetermined threshold value (Check size), the control device 60 operates the algae transfer device 40 to transfer the algae from the first cultivation tank 11 to the second cultivation tank 12. According to this configuration, by transferring the algae to a cultivation tank 10 with a larger volume according to the growth degree of the algae so as to keep the density of the algae in each cultivation tank 10 constant, the arrival of light necessary for the photosynthesis of the algae can be stabilized, and the algae can be cultivated with high efficiency.

[0066] In addition, in the algae cultivation device 1 according to the present embodiment, the control device 60 determines the presence or absence of algae diseases based on the color of the algae photographed by the photographing device 50. According to this configuration, for example, diseases caused by pathogenic microorganisms such as "white rot disease" and "red rot disease" of seaweed can also be grasped.

[0067] In addition, the algae cultivation device 1 according to the present embodiment includes a waste tank 30 for discarding the algae. When the color development range of the algae of a predetermined color exceeds a predetermined threshold value, the control device 60 operates the algae transfer device 40 to transfer the algae from the cultivation tank 10 to the waste tank 30. According to this configuration, since the algae affected by the disease can be quickly discarded, the loss cost due to the occurrence of the disease can be reduced.

[0068] Also, in the algae cultivation device 1 according to the present embodiment, the cultivation tank 10 is provided with cultivation water for cultivating algae, and a measuring device 51 (pH detector, carbon dioxide dissolution detector, liquid analyzer, etc.) for measuring the state quantity of the cultivation water. According to this configuration, an optimal cultivation environment (pH, carbon dioxide solubility, nutrient amount, etc.) can be formulated according to the type of algae, and the algae can be cultivated with high efficiency by managing and controlling the cultivation environment according to the degree of algae cultivation. In addition, by the above-mentioned formulation, stable supply of algae becomes possible, and by taking the correlation with nutritional value, taste, etc., the commercial value can be increased, contributing to the branding of algae production.

[0069] Further, the algae cultivation device 1 according to the present embodiment includes a cultivation tank 10 for cultivating algae with cultivation water, and an ultraviolet sterilization device 2 for exposing the algae to ultraviolet rays by drying them out from the cultivation water. According to this configuration, diatoms that adhere to the algae, consume the carbon dioxide added to the cultivation water, repeat photosynthesis, and further grow faster than the target algae to be cultivated and block the absorption of light by the target algae can be removed by ultraviolet irradiation. In addition, a photographing device 50 for photographing algae may be provided preliminarily in the ultraviolet sterilization tank 20 of the ultraviolet sterilization device 2.

[0070] Also, in the algae cultivation device 1 according to the present embodiment, the ultraviolet sterilization device 2 includes an ultraviolet sterilization tank 20 that receives algae and cultivation water from the cultivation tank 10, a net member 21 provided inside the ultraviolet sterilization tank 20 for separating the cultivation water from the algae, and an ultraviolet light source 22 that irradiates ultraviolet rays to the algae supported by the net member 21. According to this configuration, it is possible to simulate the drying and wetting process of seawater in nature by sunlight and ultraviolet rays, and efficiently remove diatoms attached to the algae.

[0071] Also, in the algae cultivation device 1 according to the present embodiment, the ultraviolet sterilization device 2 includes a cultivation water transfer device 23 for lowering the water level of the cultivation water in the ultraviolet sterilization tank 20 below the net member 21. According to this configuration, since the cultivation water can be transferred (drained) from the ultraviolet sterilization tank 20, the water level can be lowered without installing a large-volume ultraviolet sterilization tank 20, and the algae can be dried out from the cultivation water by the net member 21.

[0072] Also, in the algae cultivation device 1 according to the present embodiment, the cultivation water transfer device 23 returns the cultivation water after ultraviolet irradiation and raises the water level of the cultivation water in the ultraviolet sterilization tank 20 above the net member 21. According to this configuration, by returning the cultivation water to the ultraviolet sterilization tank 20, the algae supported by the net member 21 can be floated by the cultivation liquid, enabling the transfer of the algae.

[0073] Also, in the algae cultivation device 1 according to the present embodiment, the ultraviolet sterilization tank 20 is provided with a lower water level gauge 24 for detecting that the water level of the cultivation water is lower than the net member 21. According to this configuration, the water level of the cultivation water in the ultraviolet sterilization tank 20 can be surely lowered below the net member 21.

[0074] Also, in the algae cultivation device 1 according to the present embodiment, the ultraviolet sterilization tank 20 is provided with an upper water level gauge 25 for detecting that the water level of the cultivation water is higher than the net member 21. According to this configuration, the water level of the cultivation water in the ultraviolet sterilization tank 20 can be surely raised above the net member 21.

[0075] Also, in the algae cultivation device 1 according to the present embodiment, the ultraviolet sterilization device 2 is provided with a moving device 26 for moving the net member 21 closer to and farther from the ultraviolet light source 22. According to this configuration, by moving the net member 21 closer to and farther from the ultraviolet light source 22, the exposure condition of ultraviolet rays to the algae can be adjusted.

[0076] Also, in the algae cultivation device 1 according to the present embodiment, the ultraviolet sterilization device 2 is provided with an ultraviolet light emitting diode that emits ultraviolet rays. According to this configuration, ultraviolet rays can be irradiated to the algae with power saving.

[0077] 〔Second Embodiment〕 Next, a second embodiment of the present invention will be described. In the following description, the same reference numerals are given to the same or equivalent configurations as those in the above-described embodiment, and the description thereof will be simplified or omitted.

[0078] FIG. 7 is a configuration diagram of the algae cultivation apparatus 1 according to the second embodiment. The algae cultivation apparatus 1 of the second embodiment includes a continuous ultraviolet sterilization apparatus 2 that performs ultraviolet irradiation in the process of transferring algae from the first cultivation tank 11 to the second cultivation tank 12, instead of the batch-type ultraviolet sterilization apparatus 2 described in the first embodiment. Although not shown, a continuous ultraviolet sterilization apparatus 2 is similarly provided in the process of transferring algae from the second cultivation tank 12 to the third cultivation tank 13 to perform ultraviolet irradiation on the algae.

[0079] The ultraviolet sterilization apparatus 2 shown in FIG. 7 is provided in the middle of the first transfer line 41A that transfers algae from the first cultivation tank 11 to the second cultivation tank 12. An opening / closing valve 41b is provided in the first transfer line 41A upstream of the ultraviolet sterilization apparatus 2. Also, an opening / closing valve 41c is provided in the first transfer line 41A downstream of the ultraviolet sterilization apparatus 2.

[0080] The ultraviolet sterilization apparatus 2 includes an exposure apparatus 70 that exposes and transfers algae from the cultivation water, and an ultraviolet light source 22 that irradiates ultraviolet rays on the algae being transferred by the exposure apparatus 70. The exposure apparatus 70 includes an exposure preparation tank 71, a conveyor device 72, a transfer control device 73, a water receiving tank 74, and an exposure completion tank 75. Incidentally, the above-described imaging device 50 for imaging algae may be provided preliminarily on the conveyor device 72 as well.

[0081] The exposure preparation tank 71 is connected to the first transfer line 41A on the upstream side, and places the algae received from the first transfer line 41A on the conveyor device 72 with a predetermined width. The conveyor device 72 transfers the algae placed from the exposure preparation tank 71. Slits, holes, etc. (not shown) are provided on the transfer surface of the conveyor device 72 so that the cultivation water and the cultivation water adhering to the algae can fall from the transfer surface, and the algae can be exposed.

[0082] The transfer control device 73 operates the conveyor device 72 under the control of the control device 60. The water receiving tank 74 is disposed below the conveyor device 72 and receives the cultivation water that has fallen from the conveying surface of the conveyor device 72. The dry-out completion tank 75 is disposed downstream of the conveyor device 72, receives the algae from the conveyor device 72, and also receives the cultivation water from the water receiving tank 74. The dry-out completion tank 75 is connected to the first transfer line 41A on the downstream side, and transfers the algae and the cultivation water that have undergone ultraviolet sterilization treatment to the next cultivation tank 10.

[0083] The ultraviolet light source 22 is installed on the conveying path of the conveyor device 72. An air blower 76 is installed upstream of the ultraviolet light source 22 on the conveying path. The air blower 76 operates under the control of the control device 60, and by blowing air onto the algae upstream of the ultraviolet light source 22, promotes the falling of the cultivation water from the conveying surface of the conveyor device 72.

[0084] FIG. 8 is a flowchart for explaining the sterilization treatment of algae in the algae cultivation device 1 according to the second embodiment. The control device 60 opens the on-off valve 41b of the first transfer line 41A at the timing of transferring the algae from the first cultivation tank 11 to the second cultivation tank 12 described in the first embodiment, and causes the algae to be received from the first cultivation tank 11 into the dry-out preparation tank 71 (step S61).

[0085] Next, the control device 60 operates the air blower 76 (step S62), and operates the ultraviolet light source 22 (step S63). Then, the control device 60 starts the transfer control device 73 and operates the conveyor device 72 (step S64). The algae are dried out from the cultivation water by being placed on the conveyor device 72 from the dry-out preparation tank 71, and after being subjected to air blowing and ultraviolet irradiation during the conveyance by the conveyor device 72, are put into the dry-out completion tank 75.

[0086] Next, the control device 60 checks whether all the algae have entered the drying completion tank 75 (step S65). Note that whether all the algae have entered the drying completion tank 75 may be checked by time or by a photographing device (not shown). When all the algae have entered the drying completion tank 75 (when step S65 is "YES"), the control device 60 opens the on-off valve 41c of the first transport line 41A on the downstream side of the drying completion tank 75 (step S66). Thus, the algae are transferred from the drying completion tank 75 to the second cultivation tank 12.

[0087] According to the above-described second embodiment, since the ultraviolet sterilization device 2 includes the drying device 70 that dries and transports the algae from the cultivation water, and the ultraviolet light source 22 that irradiates the algae being transported by the drying device 70 with ultraviolet light, efficient ultraviolet sterilization treatment can be performed in the process of transferring the algae from the first cultivation tank 11 to the second cultivation tank 12.

[0088] Also, the ultraviolet sterilization device 2 of the second embodiment includes a blower device 76 that blows air to the algae upstream of the ultraviolet light source 22 in the transport path of the drying device 70. According to this configuration, by blowing air to the algae, the drying of the algae can be promoted, and the efficiency of the ultraviolet sterilization treatment can be increased.

[0089] The drying device 70 includes a conveyor device 72 that transports the algae while placing them thereon, and a water receiving tank 74 disposed below the conveyor device 72. According to this configuration, the cultivation water can be dropped from the transport surface of the conveyor device 72, and the dropped cultivation water can be received by the water receiving tank 74 and reused.

[0090] Note that the ultraviolet sterilization device 2 of the above-described second embodiment may be installed together with the ultraviolet sterilization device 2 of the first embodiment shown in FIGS. 1 and 2, and may be provided so that the ultraviolet sterilization treatment can be selected by either device. Further, the ultraviolet sterilization device 2 of the second embodiment may be provided in the middle of the first transport line 41 and the second transport line 42 shown in FIG. 1.

[0091] 〔Third Embodiment〕 Next, a third embodiment of the present invention will be described. In the following description, the same or equivalent components as those in the above-described embodiments are denoted by the same reference numerals, and the description thereof will be simplified or omitted.

[0092] FIG. 9 is a configuration diagram of the algae cultivation apparatus 1 according to the third embodiment. FIG. 10 is an external view of the algae cultivation apparatus 1 according to the third embodiment. In FIG. 9, reference numeral 3 indicates the cultivation water, and reference numeral 4 indicates the algae (the same applies to FIGS. 11 and subsequent figures described later). In the algae cultivation apparatus 1 of the third embodiment, the volumes of the first cultivation tank 11, the second cultivation tank 12, and the third cultivation tank 13 are gradually increased step by step according to the degree of algae cultivation by increasing the number of installed cultivation tanks 10. Specifically, in the first cultivation tank 11, there is 1 cultivation tank 10, in the second cultivation tank 12, there are 2 cultivation tanks 10, and in the third cultivation tank 13, there are 4 cultivation tanks 10.

[0093] On the downstream side of each cultivation tank 10, a drying-out device 70 (continuous ultraviolet sterilization device 2) for performing dehydration and drying-out of the algae described in the second embodiment is provided. Further, in the third embodiment, a seed algae selection tank 80 is connected to the third cultivation tank 13. The seed algae selection tank 80 is a tank for selecting the algae species to be cultivated next from the algae at the final stage of cultivation in the third cultivation tank 13. The seed algae selection tank 80 is connected to the first cultivation tank 11 via a seed algae supply line 81.

[0094] On the further downstream side of the drying-out device 70 that performs dehydration and drying-out of the algae on the downstream side of the third cultivation tank 13, a drying and processing device 90 for drying and processing the algae at the final stage of cultivation is provided. Also, the water treatment section (the above-described water receiving tank 74) of the drying-out device 70 that performs dehydration and drying-out of the algae on the downstream side of the third cultivation tank 13 merges on its downstream side and is connected to a large water treatment tank 100.

[0095] The water treatment tank 100 purifies the cultivation water used for the cultivation of algae to maintain water quality, and generates cultivation water by dissolving nutrient salts and carbon dioxide. As a result, the amount of seawater or artificial seawater procured as cultivation water can be reduced, and as a result, transportation costs can be reduced and the degree of freedom in the installation location of the algae cultivation device 1 can be increased. Also, at the same time, the load on the ocean, rivers, etc. due to the discharge of cultivation water can be reduced.

[0096] The water treatment tank 100 is connected to each cultivation tank 10 of the first cultivation tank 11, the second cultivation tank 12, and the third cultivation tank 13 via a cultivation water supply line 101. A pump 101A for lifting the cultivation water is provided in the cultivation water supply line 101. Subsequently, with reference to FIGS. 11 to 13, the configurations of the cultivation tank 10, the drying device 70, and the drying and processing device 90 of the third embodiment will be described.

[0097] FIG. 11 is an external view of the cultivation tank 10 according to the third embodiment. As shown in FIG. 11, the cultivation tank 10 includes a cultivation container 14 and a light irradiation device 15. The cultivation container 14 has a rectangular box shape with an open top in plan view. Above the cultivation container 14, the above-described cultivation water supply line 101 is disposed, and cultivation water is supplied from a plurality of nozzles 101a provided in the cultivation water supply line 101. A flow rate adjustment valve 101b is provided in the nozzle 101a so that the input amount (flow rate) of the cultivation water can be adjusted. Note that since the flow of the cultivation water can also be changed by changing the shape of the water channel in the cultivation container 14, the water channel may be formed so that a turbulent flow or a laminar flow can be formed in a necessary portion.

[0098] The light irradiation device 15 is disposed further above the cultivation water supply line 101 and irradiates light necessary for photosynthesis of algae inside the cultivation container 14. Inside the cultivation container 14, a plurality of fixing plates 14a that form channels for the algae and the cultivation water are provided. The plurality of fixing plates 14a are arranged alternately and form a meandering channel in the cultivation container 14. By meandering the channel in this way, the residence time of the algae in the cultivation container 14 can be lengthened.

[0099] In addition, inside the cultivation container 14, a plurality of operating plates 14b capable of shielding the flow path are provided. The operating plates 14b are slidably attached to the back sides of some fixing plates 14a. In the present embodiment, three operating plates 14b are provided so as to be able to block the flow path at three locations. In three areas on the upstream side of the three operating plates 14b inside the cultivation container 14, vent holes 14c for extracting algae from the side are provided. The vent holes 14c are provided so as to be openable and closable by an opening / closing device (not shown) and are connected to a waste tank (not shown).

[0100] Although not shown in FIG. 9, it is preferable to provide a photographing device 50 for photographing algae in each of the three areas on the upstream side of the three operating plates 14b of the cultivation container 14. The photographing device 50 may be installed above the cultivation container 14, may be fixed to the fixing plate 14a or the like and installed inside the cultivation container 14, or a transparent window may be provided in at least a part of the cultivation container 14, and the inside of the cultivation container 14 may be photographed through the window.

[0101] FIG. 12 is an external view of the drying-out device 70 according to the third embodiment. As shown in FIG. 12, the drying-out device 70 includes a drying-out preparation tank 71, a conveyor device 72, a water receiving tank 74, and a drying-out completion tank 75. The drying-out preparation tank 71 has an inlet 71a for receiving algae and cultivation water and an outlet 71b for discharging algae and cultivation water. The drying-out preparation tank 71 may be provided with a mixer that pulverizes the algae received from the inlet 71a, equalizes the size, and discharges it from the outlet 71b.

[0102] The conveyor device 72 includes a mesh belt 72a for separating the cultivation water from the algae discharged from the outlet 71b of the drying-out preparation tank 71, and a plurality of conveying rollers 72b for feeding back the mesh belt 72a. At least one of the plurality of conveying rollers 72b may be a vacuum roller that sucks the cultivation water. At the downstream end of the conveyor device 72, a pressing roller 77 for uniformly pressing the dried-out algae is provided.

[0103] The exposure device 70 of the third embodiment is provided with an imaging device 50 that images the algae being conveyed by the conveyor device 72. Other configurations are the same as those of the exposure device 70 of the second embodiment described above.

[0104] FIG. 13 is an external view of the drying and processing device 90 according to the third embodiment. As shown in FIG. 13, the drying and processing device 90 includes a conveyor device 91, a dryer 92, and a roll cutter 93. The conveyor device 91 includes a plurality of conveying rollers 91a and a mesh belt 91b that is conveyed by the plurality of conveying rollers 91a.

[0105] The dryer 92 blows hot air onto the algae placed on the mesh belt 91b to dry the algae. The roll cutter 93 cuts the algae dried by the dryer 92 into a sheet shape. The algae cut into a sheet shape are stacked and transferred to the next processing step.

[0106] FIG. 14 is a flowchart for transferring algae from the cultivation tank 10 of the algae cultivation device 1 according to the third embodiment. As shown in FIG. 14, first, the control device 60 adjusts the amount of cultivation water input to the cultivation tank 10 and determines the flow rate in the cultivation tank 10 (step S71).

[0107] Next, the control device 60 operates the imaging device 50 to acquire image data of the algae (step S72). Note that the number of times n of imaging by the imaging device 50 in step S72 may be settable from the outside. Also, the threshold value V1 for determining the degree of growth of the algae may be settable from the outside. Note that the threshold value V1 is a threshold value for determining the degree of growth in the first area (the first area) on the upstream side of the first operating plate 14b inside the cultivation container 14, and is a value based on the value Vmes obtained by calculating the volume of the algae from the image data.

[0108] Next, the control device 60 determines whether there is any disease in the algae in the first area based on the image data acquired by the imaging device 50 in the first area (step S73). When it is determined that a disease has occurred in the algae (when step S73 is "Yes"), the control device 60 closes the flow path with the first operating plate 14b and isolates the first area of the cultivation container 14 (step S74). Next, the control device 60 opens the vent hole 14c in the first area and transfers the algae from the vent hole 14c to a waste tank (not shown). Then, the algae in which the disease has occurred are disposed of in the waste tank.

[0109] When it is determined that no disease has occurred in the algae in the first area (when step S73 is "No"), the control device 60 determines whether the growth degree Vtn1 of the algae in the first area is greater than the threshold value V1 based on the image data acquired by the imaging device 50 in the first area (step S75).

[0110] When it is determined that the growth degree Vtn1 of the algae in the first area does not exceed the threshold value V1 (when step S75 is "YES"), the control device 60 closes the flow path with the first operating plate 14b and isolates the first area of the cultivation container 14 (step S76). Next, the control device 60 sets the residence time Ts1 of the algae in the first area (step S76), and retains (cultivates) the algae in the first area for the residence time Ts1 (step S78). After the elapse of the residence time Ts1, the process returns to step S73, and the control device 60 determines again the presence or absence of disease and the growth degree of the algae in the first area.

[0111] When it is determined that the growth degree Vtn1 of the algae in the first area exceeds the threshold value V1 (when step S75 is "NO"), if the first operating plate 14b is closed, the control device 60 opens the operating plate 14b (step S79). Thus, the transfer of the algae from the first area to the second area of the cultivation container 14 is completed. Note that the second area is an area on the downstream side of the first operating plate 14b and on the upstream side of the second operating plate 14b inside the cultivation container 14.

[0112] The control device 60 repeats the above steps S72 to S79 even in the second area (step S80). Thus, the transfer of algae from the second area to the third area of the cultivation container 14 is completed. The third area is the area on the downstream side of the second operating plate 14b and on the upstream side of the third operating plate 14b inside the cultivation container 14. The control device 60 repeats the above steps S72 to S79 even in the third area (step S81). Thus, the algae are transferred from the cultivation tank 10 to the drying device 70 (ultraviolet sterilization device 2).

[0113] FIG. 15 is a flowchart for transferring algae in the drying device 70 of the algae cultivation device 1 according to the third embodiment. As shown in FIG. 15, first, the control device 60 operates the blower device 76 (step S91) and operates the ultraviolet light source 22 (step S92). Then, the control device 60 activates the conveyance control device 73 and operates the conveyor device 72 (step S93).

[0114] Next, the control device 60 operates the imaging device 50 installed on the conveyor device 72, acquires image data of the algae, and performs image processing on the image data (step S94). The control device 60 acquires, for example, 10 pieces of image data captured 10 times by the imaging device 50 at an interval of 1 frame.

[0115] Next, the control device 60 determines whether there is any disease in the algae based on the image data (step S95). If a disease is found in the algae at such a conveyance stage (when step S95 is "yes"), the control device 60 stops the conveyor device 72 and interrupts the transfer and cultivation of the algae.

[0116] When it is determined that no disease has occurred in the algae at the conveyance stage (when step S95 is "no"), the control device 60 checks whether all the algae have entered the drying completion tank 75 based on the weight on the conveyor device 72 (step S96). The weight of the algae can be measured, for example, by a load cell (not shown) provided on the return roller 72b of the conveyor device 72.

[0117] When all the algae enter the dry-out tank 75 (when step S96 is "YES"), the control device 60 stops the conveyor device 72 by means of the conveyance control device 73 (step S97). Next, the control device 60 stops the ultraviolet light source 22 (step S98) and also stops the blower device 76 (step S99). By repeating the flow shown in FIGS. 14 and 15 described above, the cultivation tank 10 can be changed according to the degree of growth of the algae, and the algae can be efficiently cultivated.

[0118] As described above, the preferred embodiments of the present invention have been described with reference to the drawings. However, the present invention is not limited to the above embodiments. The various shapes and combinations of the respective constituent members shown in the above-described embodiments are merely examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

Explanation of Reference Numerals

[0119] 1 Algae cultivation device 2 Ultraviolet sterilization device 10 Cultivation tank 11 First cultivation tank 12 Second cultivation tank (second cultivation tank) 13 Third cultivation tank (second cultivation tank) 20 Ultraviolet sterilization tank 21 Net member 22 Ultraviolet light source 23 Cultivation water transfer device 24 Lower water level gauge 25 Upper water level gauge 26 Moving device 30 Waste tank 40 Algae transfer device 50 Photographing device 51 Measuring device 60 Control device 70 Dry-out device 72 Conveyor device 74 Water receiving tank 76 Blower device

Claims

1. An algae cultivation tank for cultivating algae, an algae transfer device for transferring the algae from the cultivation tank, a photographing device for photographing the algae in the cultivation tank, a second cultivation tank having a larger volume than the cultivation tank, and a control device for operating the algae transfer device based on the photographing result of the photographing device, and the control device determines the growth degree of the algae based on the size of the algae photographed by the photographing device, and when the growth degree of the algae exceeds a predetermined threshold value defined from the correlation between the surface area and weight of the algae, the control device operates the algae transfer device to transfer the algae from the cultivation tank to the second cultivation tank. An algae cultivation device characterized by this.

2. The control device determines the presence or absence of disease of the algae based on the color of the algae photographed by the photographing device. The algae cultivation device according to Claim 1, characterized by this.

3. It is provided with a waste tank for discarding the algae, and when the color development range of a predetermined color of the algae exceeds a predetermined threshold value, the control device operates the algae transfer device to transfer the algae from the cultivation tank to the waste tank. The algae cultivation device according to Claim 2, characterized by this.

4. The cultivation tank is provided with cultivation water for cultivating the algae, and is provided with a measuring device for measuring the state quantity of the cultivation water. The algae cultivation device according to any one of Claims 1 to 3, characterized by this.

5. The measuring device includes at least one of a pH detector, a carbon dioxide dissolution detector, and a liquid analysis device. The algae cultivation device according to Claim 4, characterized by this.

Images