Culture system

Abstract

To improve culture efficiency.SOLUTION: A culture system 1 includes: a receiving tank 5 for storing culture solution C for culturing photosynthetic microorganisms P; a culture tank 21A for housing the culture solution C; a culture tank 21C arranged above the culture tank 21A and housing the culture solution C; a supply pipe 34A connected to the culture tank 21A and supplying the culture solution C to the culture tank 21A; a supply pipe 34C connected to the culture tank 21C and supplying the culture solution C to the culture tank 21C; a water divider 33 arranged above the culture tanks 21A and 21C and distributing the culture solution C from the receiving tank 5 to the culture tanks 21A and 21C; and an inlet pipe 35A for introducing air into the supply pipe 34A, and having a connection end connected to the supply pipe 34A and an open end opened to the atmosphere.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a culture system. [Background technology]

[0002] In recent years, photosynthetic microorganisms that grow by photosynthesis have been attracting attention. Algae, a type of photosynthetic microorganism, are microscopic phytoplankton that grow by repeated cell division in a nutrient-containing liquid. Because algae grow quickly and are easy to cultivate, they are expected to be effectively utilized as an organic resource that can be used in various industries. For example, algae are used as a raw material for food, pharmaceuticals, adsorbents, and oils.

[0003] As a technique for culturing such photosynthetic microorganisms, Patent Document 1 describes a photosynthetic culture apparatus for culturing microalgae. This photosynthetic culture apparatus includes a culture tank, a medium supply tank, and piping and a liquid transfer pump for supplying a culture solution from the medium supply tank to the culture tank. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-231538 Summary of the Invention [Problem to be solved by the invention]

[0005] To effectively utilize the space, multiple culture tanks stacked vertically may be used. In this configuration, the supply rate of the culture medium may vary, and the time required to supply the desired amount of culture medium to the culture tank may vary depending on the height of the culture tank. In this case, the culture medium may overflow from the culture tank, resulting in a decrease in culture efficiency.

[0006] The present disclosure describes a culture system that can improve culture efficiency. [Means for solving the problem]

[0007] A culture system according to one aspect of the present disclosure comprises a receiving tank for storing a culture solution for culturing photosynthetic microorganisms, a first culture tank containing the culture solution, a second culture tank positioned above the first culture tank and containing the culture solution, a first supply pipe connected to the first culture tank and supplying the culture solution to the first culture tank, a second supply pipe connected to the second culture tank and supplying the culture solution to the second culture tank, a water distributor positioned above the first and second culture tanks and distributing the culture solution from the receiving tank to the first supply pipe and the second supply pipe, and a first introduction pipe for introducing air into the first supply pipe, the first introduction pipe having a first connection end connected to the first supply pipe and a first open end open to the atmosphere. [Effects of the Invention]

[0008] According to each aspect and embodiment of the present disclosure, it is possible to improve culture efficiency. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram schematically illustrating a culture system according to one embodiment. [Figure 2] FIG. 2 is a diagram schematically illustrating the culture section shown in FIG. [Figure 3] FIG. 3 is a detailed view of a part of the culture section shown in FIG. [Figure 4] FIG. 4 is a detailed view of a portion of the supply section shown in FIG. [Figure 5] Figure 5(a) is a diagram for explaining the supply rate of the culture medium in the culture system shown in Figure 1. Figure 5(b) is a diagram for explaining the supply rate of the culture medium in the culture system of the comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated descriptions will be omitted. An XYZ coordinate system may be shown in each drawing. The Y-axis direction is a direction that intersects (e.g., is perpendicular to) the X-axis direction and the Z-axis direction. The Z-axis direction is a direction that intersects (e.g., is perpendicular to) the X-axis direction and the Y-axis direction. As an example, the X-axis direction is the left-right direction (width direction), the Y-axis direction is the front-back direction (depth direction), and the Z-axis direction is the up-down direction (height direction).

[0011] Fig. 1 is a diagram illustrating a schematic diagram of a culture system according to one embodiment. The culture system 1 shown in Fig. 1 is a system for culturing photosynthetic microorganisms P. The culture system 1 is a closed culture system. The culture system 1 causes the photosynthetic microorganisms P to perform photosynthesis using sunlight, thereby cultivating the photosynthetic microorganisms P. The culture system 1 includes a culture section 2, a supply section 3, a discharge section 4, and a receiving tank 5.

[0012] In this embodiment, the photosynthetic microorganism P is algae. Algae are microscopic phytoplankton that grow by photosynthesis in a culture solution and repeated cell division. Examples of such algae include green algae (Chlorella, Chlamydomonas, Haematococcus, Botryococcus, and Dunaliella), Treboxia algae (Parachlorella), Prasinophyte, cyanobacteria (Spirulina, Arthrostra, Synechococcus, Synechocystis, and Nostoc), Haptophyte (Pleurochrysis), Diatom (Chaetoceros), Euglena. For example, Spirulina is a microalgae measuring 500 μm to 600 μm in length and can be used as a food ingredient containing abundant nutrients. The type of photosynthetic microorganism P is not particularly limited.

[0013] The culture unit 2 is a section where photosynthetic microorganisms P are cultured. The culture unit 2 is placed outdoors so that the photosynthetic microorganisms P can perform photosynthesis. The culture unit 2 includes a plurality of culture tanks. In this embodiment, the culture unit 2 includes three culture tanks (culture tank 21A, culture tank 21B, and culture tank 21C).

[0014] Each of the culture tanks 21A, 21B, and 21C is a container that contains a culture solution C for culturing photosynthetic microorganisms P. In this specification, the culture solution C does not mean only the culture solution, but also the culture solution containing photosynthetic microorganisms P. Each of the culture tanks 21A, 21B, and 21C has a bag-like shape that extends in the left-right direction. Each of the culture tanks 21A, 21B, and 21C is made of, for example, a light-transmitting resin sheet. Examples of the light-transmitting resin sheet that can be used include transparent sheets made of polyethylene, nylon, urethane, or the like. The culture tank 21A (first culture tank), the culture tank 21B, and the culture tank 21C (second culture tank) are arranged in this order in the vertical direction. The culture tank 21B is provided above the culture tank 21A, and the culture tank 21C is provided above the culture tanks 21A and 21B. Details of the culture unit 2 will be described later.

[0015] The supply unit 3 is a part that supplies the culture solution C to each of the culture tanks 21A, 21B, and 21C. The supply unit 3 includes a main supply pipe 31, a pump 32, a water divider 33, supply pipes (supply pipes 34A, 34B, and 34C) in the same number as the culture tanks included in the culture unit 2, introduction pipes (introduction pipes 35A, 35B, and 35C) in the same number as the supply pipes, and a return pipe 36.

[0016] The main supply pipe 31 is a pipe for supplying the culture solution C stored in the receiving tank 5 to each culture tank. One end of the main supply pipe 31 is connected to the receiving tank 5. The other end of the main supply pipe 31 is connected to a water divider 33. A pump 32 is provided on the main supply pipe 31. When the pump 32 is driven, the culture solution C stored in the receiving tank 5 flows sequentially through the main supply pipe 31, the water divider 33, and each supply pipe to each culture tank. The pump 32 is driven and controlled by an inverter (not shown). The inverter starts or stops the supply of the culture solution C by the pump 32 based on commands from a control device (not shown).

[0017] The water distributor 33 distributes the culture solution C supplied from the receiving tank 5 through the main supply pipe 31 to the supply pipes 34A, 34B, and 34C. The water distributor 33 is disposed above any of the culture tanks included in the culture unit 2.

[0018] Supply pipe 34A is connected to culture tank 21A and supplies culture solution C to culture tank 21A. One end of supply pipe 34A is connected to water divider 33. The other end of supply pipe 34A is connected to supply port 26f (see FIG. 2) of culture tank 21A. Supply pipe 34B is connected to culture tank 21B and supplies culture solution C to culture tank 21B. One end of supply pipe 34B is connected to water divider 33. The other end of supply pipe 34B is connected to supply port 26f (see FIG. 2) of culture tank 21B. Supply pipe 34C is connected to culture tank 21C and supplies culture solution C to culture tank 21C. One end of supply pipe 34C is connected to water divider 33. The other end of supply pipe 34C is connected to supply port 26f (see FIG. 2) of culture tank 21C. One end of the supply pipe 34A, one end of the supply pipe 34B, and one end of the supply pipe 34C are connected to the water divider 33 at substantially the same height.

[0019] Inlet pipe 35A is connected to supply pipe 34A and introduces air into supply pipe 34A. Inlet pipe 35B is connected to supply pipe 34B and introduces air into supply pipe 34B. Inlet pipe 35C is connected to supply pipe 34C and introduces air into supply pipe 34C. Details of inlet pipes 35A, 35B, and 35C will be described later.

[0020] The return pipe 36 is a pipe for returning the culture solution C from the water divider 33 to the receiving tank 5. More specifically, the return pipe 36 returns the remaining culture solution C, which is supplied from the receiving tank 5 via the main supply pipe 31 and has not been distributed to the supply pipes 34A, 34B, and 34C, back to the receiving tank 5. One end of the return pipe 36 is connected to the water divider 33. The other end of the return pipe 36 is connected to the receiving tank 5.

[0021] The discharge unit 4 is a part that discharges the culture solution C from the culture unit 2. The discharge unit 4 includes a discharge pipe 41, connecting pipes 42 in the same number as the culture tanks included in the culture unit 2, valves 43 in the same number as the connecting pipes 42, and overflow pipes 44 in the same number as the culture tanks included in the culture unit 2. The discharge pipe 41 is a pipe for discharging the culture solution C in the culture tanks 21A, 21B, and 21C. In this embodiment, the discharge pipe 41 discharges the culture solution C into the receiving tank 5. The discharge pipe 41 extends in the vertical direction. The discharge pipe 41 is in communication with each of the culture tanks 21A, 21B, and 21C via the connecting pipes 42.

[0022] One end of the communicating pipe 42 is connected to an outlet 26e (see FIG. 2) provided in the bottom 26a (see FIG. 2) of the culture tank corresponding to the communicating pipe 42. The other end of the communicating pipe 42 is connected to a discharge pipe 41. For example, the culture solution C in the culture tank flows through the communicating pipe 42 to the discharge pipe 41, thereby discharging the culture solution C from the culture tank. Each communicating pipe 42 is provided with a valve 43. The valve 43 adjusts the amount of culture solution C discharged to the discharge pipe 41 through the communicating pipe 42 to which the valve 43 is provided. By operating the valve 43, the amount of culture solution C discharged from the culture tank corresponding to the valve 43 can be adjusted. Examples of the valve 43 include a manual valve and an electromagnetic valve.

[0023] One end of the overflow pipe 44 is connected to the side wall portion 26b (see FIG. 2) of the culture tank corresponding to the overflow pipe 44. The other end of the overflow pipe 44 is connected to the discharge pipe 41. Culture solution C in excess of the desired amount in the culture tank is discharged to the discharge pipe 41 via the overflow pipe 44 connected to the culture tank. In other words, the vertical position (height) at which the overflow pipe 44 is connected to the culture tank determines the desired amount of culture solution C in the culture tank.

[0024] The receiving tank 5 is a tank that stores the culture solution C. The receiving tank 5 stores the culture solution C discharged from the lower end of the discharge pipe 41. In this embodiment, the receiving tank 5 is provided below the discharge pipe 41. The receiving tank 5 may be connected to the lower end of the discharge pipe 41 via, for example, a pipe. In this case, the position where the receiving tank 5 is placed is not particularly limited. The capacity of the receiving tank 5 is larger than the total volume of the culture solution C supplied to all the culture tanks included in the culture unit 2. The receiving tank 5 has, for example, a rectangular parallelepiped shape.

[0025] Next, the culture unit 2 will be described in detail with reference to Figures 2 and 3. Figure 2 is a diagram schematically illustrating the culture unit shown in Figure 1. Figure 3 is a diagram illustrating in detail a portion of the culture unit shown in Figure 2. As shown in Figures 2 and 3, in addition to culture tanks 21A, 21B, and 21C, the culture unit 2 includes a pair of supports 22, beams 23 in the same number as the culture tanks included in the culture unit 2, air vent pipes 24 in the same number as the culture tanks included in the culture unit 2, and an aeration device 25.

[0026] Each support 22 extends in the vertical direction. A pair of support columns 22 are spaced apart from each other in the left-right direction. Each beam 23 is provided for each culture tank and is a member for supporting the corresponding culture tank. Each beam 23 extends in the left-right direction and is bridged between a pair of support columns 22. The three beams 23 are spaced apart from each other in the vertical direction. The distance between one beam 23 and another beam 23 adjacent to that one beam 23 in the vertical direction is longer than the length of the culture tank in the vertical direction. Each of the culture tanks 21A, 21B, and 21C is attached to the corresponding beam 23 and suspended from the beam 23. An example of the material for the support columns 22 and the beams 23 is metal.

[0027] 3, each of the culture tanks 21A, 21B, and 21C includes a main body 26, an attachment portion 27, and an upper wall 28. Since the culture tanks 21A, 21B, and 21C have the same configuration, only the configuration of the culture tank 21A will be described here.

[0028] The mounting portion 27 is a portion for mounting the culture tank 21A to the beam 23. The mounting portion 27 is located at the upper end of the culture tank 21A, and is located higher than the upper wall portion 28. In this embodiment, the mounting portion 27 has a cylindrical shape that extends in the left-right direction and is open on both the left and right ends (see FIG. 2). The beam 23 is inserted into the cylindrical mounting portion 27. The upper wall portion 28 is a portion that extends in the left-right direction and separates the main body portion 26 and the mounting portion 27 in the up-down direction. The upper wall portion 28 is formed, for example, by welding together wall portions of the culture tank 21A that face each other in the front-rear direction.

[0029] The main body 26 is a portion that defines a space for culturing photosynthetic microorganisms P. The main body 26 is located below the upper wall 28. The main body 26 includes a bottom 26a, a side wall 26b (see FIG. 2), a partition wall 26c, and a partition wall 26d. The bottom 26a is a wall that forms the lower end of the main body 26. The bottom 26a is provided with an outlet 26e for discharging the culture solution C in the culture tank 21A. The side wall 26b is a wall that connects the upper wall 28 and the bottom 26a. The side wall 26b is provided with a supply port 26f (see FIG. 2) for supplying the culture solution C into the culture tank 21A.

[0030] The partition walls 26c divide the inside of the main body 26 of the culture tank 21A into a plurality of cells L. In the present embodiment, the main body 26 includes a plurality of partition walls 26c. Each partition wall 26c extends in the up-down direction inside the main body 26. The plurality of partition walls 26c are provided at intervals from one another in the left-right direction. The partition walls 26c are formed, for example, by welding together the side wall portions 26b that face each other in the front-rear direction. The partition walls 26c may be formed, for example, by heat sealing.

[0031] In this embodiment, an air vent slit is formed between the upper end of each partition wall 26c and the upper wall portion 28. A water vent slit is formed between the lower end of each partition wall 26c and the bottom portion 26a. The cells L communicate with each other through these slits. The liquid levels of the culture solution C in the cells L are substantially equal to each other.

[0032] In the present embodiment, the main body 26 includes a plurality of partition walls 26d. Two partition walls 26d are provided within each cell L. The partition walls 26d extend in the up-down direction inside the main body 26. The lower ends of the partition walls 26d are located above the bottom 26a. A lower communication port 29a is provided between the lower ends of the partition walls 26d and the bottom 26a. The upper ends of the partition walls 26d are located below the upper wall 28. An upper communication port 29b is provided between the upper ends of the partition walls 26d and the upper wall 28. The partition walls 26d are formed, for example, by welding the side wall portions 26b facing each other in the front-rear direction. The partition walls 26d may be formed, for example, by heat sealing.

[0033] Within each cell L, two partition walls 26d divide the cell L into an air diffusion chamber V1 and a pair of culture chambers V2. The air diffusion chamber V1 is provided between the two partition walls 26d provided in the cell L. Gas is supplied to the air diffusion chamber V1 through air diffusion holes 26g provided in the bottom 26a. One air diffusion hole 26g is provided for each air diffusion chamber V1. The air diffusion holes 26g are provided below the corresponding air diffusion chamber V1. Each air diffusion hole 26g is equipped with a spout that discharges gas. When gas is supplied to the air diffusion chamber V1, an upward flow of the culture solution C is formed within the air diffusion chamber V1. The culture chamber V2 is a section for culturing photosynthetic microorganisms P. The culture chamber V2 is formed between the partition wall 26c and the partition wall 26d. The pair of culture chambers V2 sandwich the air diffusion chamber V1 in the left-right direction.

[0034] The air diffusion chamber V1 and the culture chamber V2 extend vertically along the partition wall 26d. The air diffusion chamber V1 and the culture chamber V2 communicate with each other below the partition wall 26d via a lower communication port 29a. The air diffusion chamber V1 and the culture chamber V2 communicate with each other above the partition wall 26d via an upper communication port 29b. The air diffusion chamber V1 and the culture chamber V2 provide a flow path for the culture solution C circulating within the main body 26 of the culture tank 21A.

[0035] The air vent pipe 24 is a pipe for venting air from inside the main body 26. The air vent pipe 24 is inserted through the upper wall 28. The air vent pipe 24 connects the inside and outside of the main body 26 with each other.

[0036] The air diffuser 25 is a device that supplies gas to the air diffusion chamber V1. The air diffuser 25 includes a blower 51 and a pipe 52. The pipe 52 is connected to the air diffusion hole 26g via the spout. The blower 51 supplies gas to the air diffusion chamber V1 via the pipe 52. The gas supplied by the blower 51 is, for example, air. The blower 51 supplies gas from the air diffusion hole 26g to the air diffusion chamber V1. The blower 51 may supply exhaust gas containing carbon dioxide to the air diffusion chamber V1 to promote photosynthesis by the photosynthetic microorganisms P.

[0037] When culturing photosynthetic microorganisms P using the culture unit 2, first, culture solution C is supplied into the culture tank from outside the culture tank. At this time, the culture solution C is supplied so that the liquid level of the culture solution C in the culture chamber V2 is a predetermined distance above the upper end of the partition wall 26d. The culture solution C may also be supplied so that the liquid level of the culture solution C in the culture chamber V2 is below the upper end of the partition wall 26d. Next, gas is supplied from the blower 51 to the culture solution C in the plurality of air diffusion chambers V1 through the plurality of air diffusion holes 26g.

[0038] When gas is supplied into the plurality of air diffusion chambers V1 through the plurality of air diffusion holes 26g, an upward flow is formed in the culture solution C in the air diffusion chamber V1 of each cell L due to the air lift effect, and the liquid level of the culture solution C in the air diffusion chamber V1 rises. The culture solution C in the air diffusion chamber V1 that has exceeded the height of the upper end of the partition wall 26d flows into the pair of culture chambers V2 through the upper communication port 29b. The culture solution C that has flowed into the pair of culture chambers V2 forms a downward flow in the culture solution C in the pair of culture chambers V2 toward the bottom 26a.

[0039] The culture solution C that moves downward within the pair of culture chambers V2 and reaches the bottom 26a is returned to the air diffusion chamber V1 through the lower communication port 29a. In this way, in each cell L, the culture solution C in the culture tank circulates between the air diffusion chamber V1 and the pair of culture chambers V2.

[0040] Next, the introduction pipes 35A, 35B, and 35C will be described in detail with reference to Figure 4. Figure 4 is a diagram showing in detail a portion of the supply unit shown in Figure 1. As shown in Figure 4, each of the supply pipes 34A, 34B, and 34C has a connection end 34a, including one end connected to the water divider 33. The connection end 34a extends from the water divider 33, has rigidity, and is not easily deformed. The portions of each supply pipe other than the connection end 34a are flexible. The connection end 34a (first connection end) of the supply pipe 34A, the connection end 34a of the supply pipe 34B, and the connection end 34a (second connection end) of the supply pipe 34C are arranged at substantially the same position (substantially the same height) in the vertical direction.

[0041] The inlet pipe 35A is connected to a connection end 34a of the supply pipe 34A. The inlet pipe 35A extends in the vertical direction. The inlet pipe 35A has a connection end 38A (first connection end) connected to the supply pipe 34A and an open end 39A (first open end) that opens to the atmosphere (outside the culture system 1). The connection end 38A is connected to the connection end 34a of the supply pipe 34A. The open end 39A is provided at a higher position than the return pipe 36. In other words, the inlet pipe 35A extends from the connection end 34a of the supply pipe 34A to a higher position than the return pipe 36. The tip portion of the inlet pipe 35A, including the open end 39A, is curved horizontally, and the open end 39A opens horizontally. When the supply pipe 34A is filled with the culture solution C, a siphon effect occurs within the supply pipe 34A. At this time, a vacuum is created inside supply pipe 34A, so air enters introduction pipe 35A from open end 39A, passes through introduction pipe 35A, and is supplied into supply pipe 34A from connection end 38A.

[0042] Inlet pipe 35B is connected to connection end 34a of supply pipe 34B. Inlet pipe 35B extends in the vertical direction. Inlet pipe 35B has connection end 38B connected to supply pipe 34B and open end 39B that is open to the atmosphere. Connection end 38B is connected to connection end 34a of supply pipe 34B. Open end 39B is located at a higher position than return pipe 36. In other words, inlet pipe 35B extends from connection end 34a of supply pipe 34B to a higher position than return pipe 36. The tip portion of inlet pipe 35B, including open end 39B, is curved horizontally, and open end 39B opens horizontally. When supply pipe 34B is filled with culture solution C, a siphon effect occurs within supply pipe 34B. At this time, a vacuum state is created inside supply pipe 34B, so air enters introduction pipe 35B from open end 39B, passes through introduction pipe 35B, and is supplied into supply pipe 34B from connection end 38B.

[0043] The inlet pipe 35C is connected to the connection end 34a of the supply pipe 34C. The inlet pipe 35C extends in the vertical direction. The inlet pipe 35C has a connection end 38C (second connection end) connected to the supply pipe 34C and an open end 39C (second open end) that is open to the atmosphere. The connection end 38C is connected to the connection end 34a of the supply pipe 34C. The open end 39C is located at a higher position than the return pipe 36. In other words, the inlet pipe 35C extends from the connection end 34a of the supply pipe 34C to a higher position than the return pipe 36. The tip portion of the inlet pipe 35C, including the open end 39C, is curved horizontally, and the open end 39C opens horizontally. When the supply pipe 34C is filled with the culture solution C, a siphon effect occurs within the supply pipe 34C. At this time, a vacuum is created inside supply pipe 34C, so air enters introduction pipe 35C from open end 39C, passes through introduction pipe 35C, and is supplied into supply pipe 34C from connection end 38C.

[0044] In this embodiment, the connection ends 38A, 38B, and 38C are provided at substantially the same position (substantially the same height) in the up-down direction.

[0045] Next, the effects of the culture system 1 will be described with reference to Figures 5(a) and 5(b). Figure 5(a) is a diagram illustrating the supply rate of the culture medium in the culture system shown in Figure 1. Figure 5(b) is a diagram illustrating the supply rate of the culture medium in a culture system of a comparative example. The culture system 100 shown in Figure 5(b) is mainly different from the culture system 1 in that the supply unit 3 does not include the introduction pipes 35A, 35B, and 35C.

[0046] As shown in FIG. 5(b), in the culture system 100, the culture solution C stored in the receiving tank 5 is supplied to the water distributor 33 through the main supply pipe 31 by driving the pump 32. When the culture solution C is distributed from the water distributor 33 to each supply pipe, the supply pipes are filled with the culture solution C, and a siphon effect occurs in each supply pipe. Here, the difference in vertical position between one end and the other end of the supply pipe 34A (height difference Ha), the difference in vertical position between one end and the other end of the supply pipe 34B (height difference Hb), and the difference in vertical position between one end and the other end of the supply pipe 34C (height difference Hc) are all different. Because the ends of the supply pipes 34A, 34B, and 34C are located at the same height, the greater the difference in height between the supply pipes, the greater the propulsive force of the culture solution C due to the siphon effect.

[0047] Because supply port 26f (the other end of supply pipe 34A) of culture tank 21A is located at the lowest position, the propulsive force of culture solution C due to siphoning in supply pipe 34A is greatest, and the amount of culture solution C supplied per unit time is greatest. In other words, the supply rate of culture solution C in supply pipe 34A is greatest. Because supply port 26f (the other end of supply pipe 34C) of culture tank 21C is located at the highest position, the propulsive force of culture solution C due to siphoning in supply pipe 34C is least, and the amount of culture solution C supplied per unit time is least. In other words, the supply rate of culture solution C in supply pipe 34C is least. Since the supply port 26f of the culture tank 21B (the other end of the supply pipe 34B) is located between the supply port 26f of the culture tank 21A and the supply port 26f of the culture tank 21C, the supply amount (supply rate) of the culture solution C per unit time in the supply pipe 34B is approximately intermediate between the supply rate of the supply pipe 34A and the supply rate of the supply pipe 34C.

[0048] Therefore, first, the culture solution C reaches the desired amount in culture tank 21A, then the culture solution C reaches the desired amount in culture tank 21B, and finally the culture solution C reaches the desired amount in culture tank 21C. Since pump 32 continues to operate until the culture solution C reaches the desired amount in all culture tanks included in culture unit 2, culture solution C continues to be supplied to culture tanks 21A and 21B even after the culture solution C reaches the desired amount, and culture solution C exceeding the desired amount is returned to receiving tank 5 through overflow pipe 44 and discharge pipe 41. Then, the culture solution C returned to receiving tank 5 is supplied again by pump 32 through main supply pipe 31 to water divider 33, and distributed from water divider 33 to each supply pipe. As described above, the circulation of culture solution C increases the number of times photosynthetic microorganisms P are caught in the impeller of pump 32, which may shred the photosynthetic microorganisms P and reduce the culture efficiency.

[0049] 5(a), in the culture system 1, air is introduced into supply pipe 34A through inlet pipe 35A, into supply pipe 34B through inlet pipe 35B, and into supply pipe 34C through inlet pipe 35C. Because no siphoning occurs downstream of the position where air is introduced into supply pipe 34A (the position where supply pipe 34A is connected to connection end 38A), downstream of this position, it can be considered that the culture solution C is being supplied through a pipe having an inner diameter that is not filled with the culture solution C. Similarly, no siphoning occurs downstream of the position where air is introduced into supply pipe 34B (the position where supply pipe 34B is connected to connection end 38B), and no siphoning occurs downstream of the position where air is introduced into supply pipe 34C (the position where supply pipe 34C is connected to connection end 38C).

[0050] Among the culture tanks included in the culture unit 2, the culture tank to which the culture solution C is supplied at the highest supply rate has the shortest time required to supply the desired amount of culture solution C, and the culture tank to which the culture solution C is supplied at the lowest supply rate has the longest time required to supply the desired amount of culture solution C. Therefore, by reducing the speed difference between the maximum and minimum supply rates, the amount of culture solution C overflowing from the culture tanks can be reduced. In the culture system 1, compared to the culture system 100, the differences between the supply rates of the culture solution C supplied to the culture tank 21A, the culture tank 21B, and the culture tank 21C are smaller. In other words, the time difference required to supply the desired amount of culture solution C to the culture tanks 21A, 21B, and 21C is reduced, thereby reducing the amount of culture solution C overflowing from the culture tanks. Therefore, compared to the culture system 100, the number of times photosynthetic microorganisms P are caught in the impeller of the pump 32 is reduced, thereby reducing the possibility of the photosynthetic microorganisms P being shredded. As a result, it is possible to improve the culture efficiency.

[0051] It is also conceivable to reduce the effects of siphoning by increasing the liquid delivery rate (supply rate) of the pump 32, thereby strengthening the propulsion force of the culture solution C in each supply pipe. In this case, since the rotation speed of the impeller of the pump 32 is high, there is a risk that the photosynthetic microorganisms P may be shredded by the rotation of the impeller, resulting in a decrease in culture efficiency. In contrast, in the culture system 1, the effects of siphoning can be reduced without increasing the liquid delivery rate (supply rate) of the pump 32 more than necessary. Therefore, the possibility of the photosynthetic microorganisms P being shredded can be reduced, making it possible to improve culture efficiency.

[0052] Furthermore, connection end 38A, connection end 38B, and connection end 38C are provided at substantially the same position (substantially the same height) in the vertical direction. That is, the height difference between sections where siphoning occurs in supply pipes 34A, 34B, and 34C is substantially the same height difference Hs. Therefore, the propulsive force of culture solution C due to siphoning occurring in supply pipe 34A, the propulsive force of culture solution C due to siphoning occurring in supply pipe 34B, and the propulsive force of culture solution C due to siphoning occurring in supply pipe 34C are substantially equal. This makes it possible to equalize the supply rate of culture solution C supplied to culture tank 21A, the supply rate of culture solution C supplied to culture tank 21B, and the supply rate of culture solution C supplied to culture tank 21C. This further reduces the amount of culture solution C overflowing from the culture tank. As a result, it is possible to further improve the culture efficiency.

[0053] In this embodiment, connection ends 38A, 38B, and 38C are connected to connection ends 34a of supply pipes 34A, 34B, and 34C, respectively. Because connection ends 34a have rigidity, the heights of connection ends 38A, 38B, and 38C can be stably maintained.

[0054] If open end 39A is located at a position lower than the highest part of return pipe 36, culture solution C may pass through inlet pipe 35A and flow out from open end 39A to the outside. Similarly, if open end 39B is located at a position lower than the highest part of return pipe 36, culture solution C may pass through inlet pipe 35B and flow out from open end 39B to the outside. If open end 39C is located at a position lower than the highest part of return pipe 36, culture solution C may pass through inlet pipe 35C and flow out from open end 39C to the outside. In contrast, in culture system 1, all of open ends 39A, 39B, and 39C are located at a position higher than return pipe 36 (the highest part of return pipe 36), so that culture solution C is prevented from passing through inlet pipes 35A, 35B, and 35C and flowing out from open ends 39A, 39B, and 39C to the outside. Therefore, the culture solution C that has not been distributed to the supply pipes 34A, 34B, 34C is returned from the water divider 33 to the receiving tank 5 through the return pipe 36. Therefore, the utilization efficiency of the culture solution C can be improved.

[0055] In the culture system 1, since the multiple culture tanks are arranged vertically, the installation area for installing the culture system 1 can be reduced compared to a configuration in which the multiple culture tanks are arranged horizontally, thereby enabling space saving. Furthermore, in the culture system 1, by arranging the multiple culture tanks vertically, the possibility that light will be blocked by other culture tanks is reduced. Therefore, the light receiving area can be made larger compared to a configuration in which the multiple culture tanks are arranged horizontally.

[0056] The culture system according to the present disclosure is not limited to the above embodiment.

[0057] The culture system 1 (culture unit 2) may include two or more culture tanks arranged in the vertical direction. In this case, the numbers of supply pipes for supplying the culture solution C to the culture tanks, introduction pipes for introducing air into the supply pipes, communication pipes 42, overflow pipes 44, etc. may be appropriately changed depending on the number of culture tanks.

[0058] Connection end 38A, connection end 38B, and connection end 38C may be provided at different positions (different heights) in the vertical direction as long as the speed difference between the maximum supply speed and the minimum supply speed is reduced compared to culture system 100. If the difference in height between the uppermost and lowermost connection ends among connection ends 38A, 38B, and 38C is smaller than the difference in height between the other end of supply pipe 34A and the other end of supply pipe 34C, the speed difference can be reduced.

[0059] Similarly, at least one of the supply pipes may not be provided with an inlet pipe, as long as the speed difference is reduced compared to the culture system 100. For example, only the inlet pipe 35A may be provided, without the inlet pipes 35B and 35C. In this case, the speed difference can be reduced if the maximum height difference between two of the connection end 38A, the other end of the supply pipe 34B, and the other end of the supply pipe 34C is smaller than the height difference between the other end of the supply pipe 34A and the other end of the supply pipe 34C.

[0060] In other words, by making the difference in elevation between the lower ends of the sections in which siphoning occurs in supply pipes 34A, 34B, and 34C smaller than the difference in elevation between the other ends of supply pipes 34A and 34C, the speed difference can be reduced compared to culture system 100. Therefore, compared to culture system 100, the number of times photosynthetic microorganisms P are caught in the impeller of pump 32 is reduced, reducing the possibility that photosynthetic microorganisms P will be shredded. As a result, it is possible to improve culture efficiency.

[0061] Inlet pipe 35A may be supported by a member different from connection end 34a of supply pipe 34A, in which case connection end 38A of inlet pipe 35A may be connected to a different portion from connection end 34a of supply pipe 34A. Similarly, inlet pipe 35B may be supported by a member different from connection end 34a of supply pipe 34B, in which case connection end 38B of inlet pipe 35B may be connected to a different portion from connection end 34a of supply pipe 34B. Inlet pipe 35C may be supported by a member different from connection end 34a of supply pipe 34C, in which case connection end 38C of inlet pipe 35C may be connected to a different portion from connection end 34a of supply pipe 34C.

[0062] The amount of culture solution C that is not distributed to the supply pipes 34A, 34B, and 34C can be reduced by adjusting the liquid delivery rate of the pump 32. In this case, the supply unit 3 does not need to include the return pipe .

[0063] Finally, an overview of the embodiments of the present disclosure will be described.

[0064] (Article 1) a receiving tank for storing a culture solution for culturing photosynthetic microorganisms; A first culture tank containing the culture solution; A second culture tank arranged above the first culture tank and containing the culture solution; A first supply pipe connected to the first culture tank and supplying the culture medium to the first culture tank; A second supply pipe connected to the second culture tank and supplying the culture medium to the second culture tank; A water distributor arranged above the first culture tank and the second culture tank and distributing the culture solution from the receiving tank to the first supply pipe and the second supply pipe; a first introduction pipe for introducing air into the first supply pipe, the first introduction pipe having a first connection end connected to the first supply pipe and a first open end open to the atmosphere; A culture system comprising:

[0065] (Article 2) The culture system described in clause 1 further comprises a second inlet pipe for introducing air into the second supply pipe, the second inlet pipe having a second connection end connected to the second supply pipe and a second open end open to the atmosphere.

[0066] (Article 3) The culture system described in clause 2, wherein the first connection end and the second connection end are provided at the same position in the vertical direction.

[0067] (Article 4) the first supply pipe has a rigid first connection end extending from the water diverter; the second supply pipe has a rigid second connection end extending from the water diverter; the first connection end is connected to the first connection end portion; The culture system of clause 2 or clause 3, wherein the second connection end is connected to the second connection end.

[0068] (Article 5) Further provided is a return pipe for returning the culture solution from the water divider to the receiving tank, 5. The culture system according to any one of clauses 1 to 4, wherein the first open end is provided at a position higher than the return pipe.

[0069] In the culture system according to Clause 1, the culture medium from the receiving tank is distributed to the first supply pipe and the second supply pipe by a water distributor. The culture medium distributed to the first supply pipe is supplied to the first culture tank through the first supply pipe, and the culture medium distributed to the second supply pipe is supplied to the second culture tank through the second supply pipe. When each supply pipe is filled with the culture medium, a siphon phenomenon occurs in each supply pipe. Since the second culture tank is located above the first culture tank, if no inlet pipe for introducing air is provided in either supply pipe, the propulsion force of the culture medium due to the siphon phenomenon occurring in the first supply pipe is greater than the propulsion force of the culture medium due to the siphon phenomenon occurring in the second supply pipe. In other words, the supply rate of the culture medium supplied to the first culture tank is faster than the supply rate of the culture medium supplied to the second culture tank.

[0070] In the above-described culture system, air is introduced into the first supply pipe through the first inlet pipe, so that siphoning does not occur downstream of the position where air is introduced into the first supply pipe. Therefore, compared to a configuration in which neither supply pipe is provided with an inlet pipe, the difference between the supply rate of the culture medium supplied to the first culture tank and the supply rate of the culture medium supplied to the second culture tank is smaller, and the amount of culture medium overflowing from the culture tank can be reduced. As a result, the culture efficiency can be improved.

[0071] In the culture system according to Clause 2, air is introduced into the second supply pipe by the second inlet pipe, so that siphoning does not occur downstream of the position where the air is introduced into the second supply pipe. Therefore, by adjusting the vertical positions of the first and second connection ends, the difference between the supply rate of the culture medium supplied to the first culture tank and the supply rate of the culture medium supplied to the second culture tank can be reduced, thereby reducing the amount of culture medium overflowing from the culture tank. As a result, the culture efficiency can be improved.

[0072] In the culture system according to Clause 3, the first connection end and the second connection end are provided at the same vertical position, so that the propulsive force of the culture medium due to the siphon phenomenon occurring in the first supply pipe is approximately equal to the propulsive force of the culture medium due to the siphon phenomenon occurring in the second supply pipe. This makes the supply rate of the culture medium supplied to the first culture tank and the supply rate of the culture medium supplied to the second culture tank uniform. This further reduces the amount of culture medium overflowing from the culture tank. As a result, it becomes possible to further improve the culture efficiency.

[0073] In the culture system according to clause 4, the first connection end is connected to a first connection end of a first supply pipe, and the second connection end is connected to a second connection end of a second supply pipe. Since the first connection end and the second connection end have rigidity, the heights of the first connection end and the second connection end can be stably maintained.

[0074] In the culture system according to clause 5, the first open end is located higher than the return pipe, so that the culture medium is prevented from flowing out of the first open end through the first inlet pipe. Therefore, the culture medium not distributed to the first supply pipe and the second supply pipe is returned from the water divider to the receiving tank through the return pipe. This improves the utilization efficiency of the culture medium. [Explanation of symbols]

[0075] 1...cultivation system, 5...receiving tank, 21A...cultivation tank (first cultivation tank), 21C...cultivation tank (second cultivation tank), 33...water divider, 34A...supply pipe (first supply pipe), 34C...supply pipe (second supply pipe), 34a...connection end (first connection end, second connection end), 35A...inlet pipe (first inlet pipe), 35C...inlet pipe (second inlet pipe), 36...return pipe, 38A...connection end (first connection end), 38C...connection end (second connection end), 39A...open end (first open end), 39C...open end (second open end), C...culture solution, P...photosynthetic microorganism.

Claims

1. a receiving tank for storing a culture solution for culturing photosynthetic microorganisms; A first culture tank containing the culture solution; A second culture tank arranged above the first culture tank and containing the culture solution; A first supply pipe connected to the first culture tank and supplying the culture medium to the first culture tank; A second supply pipe connected to the second culture tank and supplying the culture medium to the second culture tank; A water distributor arranged above the first culture tank and the second culture tank and distributing the culture solution from the receiving tank to the first supply pipe and the second supply pipe; a first inlet pipe for introducing air into the first supply pipe, the first inlet pipe having a first connection end connected to the first supply pipe and a first open end open to the atmosphere; A culture system comprising:

2. The culture system according to claim 1, further comprising a second inlet pipe for introducing air into the second supply pipe, the second inlet pipe having a second connection end connected to the second supply pipe and a second open end open to the atmosphere.

3. The culture system according to claim 2 , wherein the first connection end and the second connection end are provided at the same position in the up-down direction.

4. Further provided is a return pipe for returning the culture solution from the water divider to the receiving tank, The culture system according to any one of claims 1 to 3, wherein the first open end is provided at a higher position than the return pipe.

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