JP2018186792A - Culture tank and culture method of algae - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a culture tank and a culture method of algae in which culture solution is not necessarily required to be transferred to another tank, and culture efficiency can be improved.SOLUTION: A culture tank used in culturing algae comprises a housing part capable of housing water or culture solution, in which the housing part has an enlarged part whose opening area on a horizontal cross section becomes larger toward an upper direction. The enlarged part has a mode of a stepped shape on a vertical cross section, for example. The enlarged part has a mode of an inclined surface on a vertical cross section, for example. The culture tank further comprises a sealing member which seals a part of an internal space of the housing part including the deepest part, for example. The culture tank further comprises a bottom surface changing unit which is capable of changing the position of at least a part of the housing part on a bottom surface between a first position and a second position which is above the first position.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a culture tank and a method for culturing algae.

  It has been proposed to produce algae oil by culturing algae using a culture tank. Algal oil can be used as bioenergy (see Patent Document 1). When culturing algae using a culture tank, it may be scaled up step by step. That is, the culture may be initially performed using a small amount of the culture solution, and then the culture may be continued by adding an amount of the culture solution.

Japanese Patent Laid-Open No. 5-284962

  In the case of scale-up, it is conceivable to use a small culture tank first, then transfer the culture medium to a large culture tank, and further add the culture medium. In addition, a method may be considered in which a large culture tank is used from the beginning, the culture is initially performed in a small amount of culture solution, and then the culture solution is added.

  In the former case, a means for transferring the culture solution is required. In the latter case, there are the following problems. When the culture solution is added to the culture tank, the depth of the culture solution increases. Then, the ratio of the part far from the liquid level in the culture solution increases. It is difficult for light to reach the culture medium far from the liquid surface. Therefore, when a culture solution is added to the culture tank, the ratio of the portion where light is difficult to reach in the culture solution increases, and the culture efficiency decreases.

  The present disclosure provides a culture tank and a method for culturing algae that can improve the culture efficiency without necessarily transferring the culture solution to another tank.

  One aspect of the present disclosure is a culture tank used for culturing algae, and includes a storage unit that can store a culture solution or water (hereinafter also referred to as a culture solution or the like), and the storage unit has a horizontal cross section. It is a culture tank which has an enlarged part where the opening area in becomes larger as it goes upwards.

  If the culture tank which is one aspect of the present disclosure is used, for example, the culture can be first performed with a small amount of a culture solution, and then the culture solution or the like can be added to perform culture. Therefore, it is not always necessary to transfer the culture solution or the like to another tank.

  Moreover, in the culture tank which is one aspect of the present disclosure, the opening area in the horizontal section of the enlarged portion is larger as it goes upward, so that when the culture solution or the like is added, the area of the liquid surface is easily enlarged. Therefore, when a culture solution or the like is added, the ratio of the portion where light enters in the culture solution or the like increases. As a result, algae can be cultured efficiently.

2 is a plan view illustrating a configuration of a culture tank 1. FIG. It is sectional drawing in the II-II cross section in FIG. It is sectional drawing in the III-III cross section in FIG. It is sectional drawing in the II-II cross section showing the state which attached the sealing member 5 to the main-body part 3. FIG. FIG. 5A is a cross-sectional view showing the culture tank 101 with the bottom change unit 21 in the lowered position, and FIG. 5B is a cross-sectional view showing the culture tank 101 with the bottom change unit 21 in the raised position. 6A is a cross-sectional view showing the culture tank 201 with the bottom change unit 23 in the retracted position, and FIG. 6B is a cross-sectional view showing the culture tank 201 with the bottom change unit 23 in the entry position. 3 is a plan view illustrating a configuration of a culture tank 301. FIG. FIG. 8A is a cross-sectional view taken along the section VIII-VIII in FIG. 8 showing the culture tank 301 with the sealing member 5 removed, and FIG. 8B shows the culture tank 301 with the sealing member 5 attached. FIG. 9 is a cross-sectional view taken along the line VIII-VIII in FIG. 8. FIG. 9A is a plan view illustrating the configuration of the culture tank 401, and FIG. 9B is a cross-sectional view taken along the line IXB-IXB in FIG. 9A. FIG. 6 is a cross-sectional view illustrating another form of the accommodating portion 3. FIG. 11A is a cross-sectional view illustrating a case where another form of sealing member 5 is in an open state, and FIG. 11B is a cross-sectional view illustrating a case where another form of sealing member 5 is in a closed state. FIG. 6 is a cross-sectional view illustrating another form of the accommodating portion 3. 4 is a cross-sectional view illustrating another form of the main body 2. FIG. FIG. 6 is a cross-sectional view illustrating another form of the accommodating portion 3.

An embodiment of the present disclosure will be described with reference to the drawings.
<First Embodiment>
1. The structure of the culture tank 1 The structure of the culture tank 1 is demonstrated based on FIGS. The culture tank 1 is used for culturing algae. The culture tank 1 includes a main body 2 shown in FIGS. 1 to 3 and a sealing member 5 shown in FIGS. 1 and 4. The basic shape of the main body 2 is a hollow rectangular parallelepiped shape having an open top. As shown in FIG. 1, the main body 2 has a rectangular shape in plan view. As shown in FIGS. 1-3, the main-body part 2 is equipped with the accommodating part 3 which can accommodate a culture solution etc. As shown in FIG. The accommodating part 3 is a recessed part opened upward.

  The accommodating portion 3 includes a rectangular first bottom surface 7 positioned in the center in plan view, a second bottom surface 9 positioned on the outer peripheral side thereof, and a third bottom surface 11 positioned further on the outer peripheral side thereof. The second bottom surface 9 is shallower than the first bottom surface 7. The third bottom surface 11 is shallower than the second bottom surface 9. The outer peripheral shapes of the second bottom surface 9 and the third bottom surface 11 are each rectangular.

  The accommodating portion 3 further includes a first side surface 13, a second side surface 15, and a third side surface 17. The first side surface 13 connects between the outer peripheral end of the first bottom surface 7 and the inner peripheral end of the second bottom surface 9. The second side surface 15 connects between the outer peripheral end of the second bottom surface 9 and the inner peripheral end of the third bottom surface 11. The third side surface 17 is erected on the outer peripheral end of the third bottom surface 11 and reaches the upper end of the main body 2.

An internal space C exists inside the housing 3. The upper part of the housing part 3 is open, and the internal space C communicates with the outside above.
As shown in FIGS. 2 and 3, in the vertical cross section, the first bottom surface 7, the second bottom surface 9, the third bottom surface 11, the first side surface 13, the second side surface 15, and the third side surface 17 are , Has a step-like form.

The opening area of the accommodating part 3 in a horizontal section is so large that it goes upwards. For example, as shown in FIGS. 2 and 3, the opening area of the accommodating portion 3 in the horizontal section where the height from the bottom 19 of the main body portion 2 is h ₁ is S _1, and the height from the bottom surface 5 is h _2. the opening area of the housing portion 3 in the horizontal section and S ₂ is, the opening area of the housing portion 3 in the horizontal section height from the bottom surface 5 is h ₃ and S _3. h ₂ is larger than h _{1 and} h ₃ is larger than h ₂ . Opening area _{S 2} than the opening area _{S 1} is larger, the opening area _{S 3} than the opening area _{S 2} is large. In addition, the whole accommodating part 3 respond | corresponds to an enlarged part. The opening area S ₃ is preferably 10000 m ² or less.

The opening area _{S 2} is preferably 3 to 100 times the opening area _{S 1.} Further, the height of the second side surface 15 is preferably 0.5 to 2 times the height of the first side surface 13. Moreover, the opening area _{S 3} is preferably 3 to 100 times the opening area _{S 2.} The height of the third side surface 17 is preferably 0.5 to 2 times the height of the second side surface 15.

When the magnitude relationship between the sizes of the opening areas S ₁ , S ₂ , and S ₃ and the magnitude relationship between the heights of the first side surface 13, the second side surface 15, and the third side surface 17 are within the above range, In the culture method of 1, the dilution rate of algae when a culture solution or the like is added is a suitable value.

The sealing member 5 is a flat member. As shown in FIGS. 1 and 4, the sealing member 5 can be bridged on the second bottom surface 9. At this time, the sealing member 5 seals the lower space C ₁ below the sealing member 5 in the internal space C. Lower space C _1, of the inner space C, and corresponds to a portion including the deepest. The sealing member 5 can also be removed from the main body 2.

2. First Culture Method Using the culture tank 1, algae can be cultured as follows. The sealing member 5 is removed from the main body 2. The culture solution or the like is stored in the storage unit 3 and the algae is cultured so that the height of the liquid level of the culture solution or the like becomes h ₁ . The amount of the culture solution or the like at this time corresponds to the first amount. Next, a culture solution or the like is added so that the height of the liquid surface of the culture solution or the like becomes h ₂ , and algae are further cultured. The amount of the culture solution or the like at this time corresponds to the second amount. Next, a culture solution or the like is added so that the height of the culture solution or the like becomes h ₃ , and algae are further cultured.

3. Second culture method Algae can be cultured using the culture tank 1 as follows. The sealing member 5 is removed from the main body 2. The culture solution or the like is stored in the storage unit 3 and the algae is cultured so that the height of the liquid level of the culture solution or the like becomes h ₁ . The amount of the culture solution or the like at this time corresponds to the first amount. Next, the sealing member 5 is attached at the position described above. Next, the height of the liquid level of the culture solution or the like to add a culture solution or the like so that h _2. In this case, the lower space C ₁ takes out the culture solution or the like may be a condition of the air may be a state in which the culture liquid or the like is accommodated. Next, algae are cultured using a culture solution or the like above the sealing member 5 and the second bottom surface 9. The amount of the culture solution or the like above the sealing member 5 and the second bottom surface 9 corresponds to the second amount. The second amount is greater than the first amount.

4). Effects produced by the culture tank 1 (1A) If the culture tank 1 is used, as in the first culture method described above, the culture is first performed with a small amount of culture solution, and then the culture solution is added and cultured. It can be performed. Therefore, it is not always necessary to transfer the culture solution or the like to another tank.

  (1B) Since the opening area in the horizontal cross section of the accommodating part 3 is so large that it goes upwards, when a culture solution etc. are added, the area of a liquid level tends to expand. Therefore, when a culture solution or the like is added, the ratio of the portion where light enters in the culture solution or the like increases. As a result, algae can be cultured efficiently.

(1C) The accommodating part 3 has a step-like form in the vertical cross section. Therefore, it is easy to control the area of the liquid level by the amount of the culture solution or the like.
(1D) The lower space C ₁ is a portion where light is difficult to reach when the amount of the culture solution is large and the liquid level is high. The culture tank 1 can seal the lower space C ₁ with the sealing member 5. For example, as in the second method of culturing described above, many amount of the culture solution or the like, when a high liquid level is to seal the lower space C ₁ by the sealing member 5, the culture solution of the portion except the lower space C ₁ Etc. can be used to culture algae. By doing so, it is possible to reduce the ratio of portions where light is difficult to reach in a culture solution or the like used for culture. As a result, algae can be cultured more efficiently.
Second Embodiment
1. Differences from the First Embodiment Since the basic configuration of the second embodiment is the same as that of the first embodiment, the differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description is referred to.

  As shown in FIGS. 5A and 5B, the culture tank 101 includes a main body 102 and a bottom surface changing unit 21. The main body 102 has a shape obtained by removing the first bottom surface 7 from the main body 2 in the first embodiment.

  The bottom surface changing unit 21 is a prismatic member. The bottom surface changing unit 21 is inserted into the space surrounded by the first side surface 13 from below. The bottom surface changing unit 21 is movable in the vertical direction. The bottom surface changing unit 21 is movable between a lowered position shown in FIG. 5A and a raised position shown in FIG. 5B.

  When the bottom surface changing unit 21 is in the lowered position, the shape of the accommodating portion 3 is the same as the shape of the accommodating portion 3 in the first embodiment. The upper end surface 107 of the bottom surface changing unit 21 is at the same position as the first bottom surface 7 in the first embodiment. The position of the upper end surface 107 at this time corresponds to the first position. The bottom surface changing unit 21 is in contact with the first side surface 13 on its side surface.

When the bottom surface changing unit 21 is in the raised position, the upper end surface 107 is flush with the second bottom surface 9. At this time, the lower space C ₁ is filled with the bottom surface changing unit 21. The position of the upper end surface 107 at this time corresponds to the second position. That is, the position of the upper end surface 107 that constitutes a part of the bottom surface of the accommodating portion 3 can be changed between the first position and the second position.

2. Culture Method Algae can be cultured using the culture tank 101 as follows. The position of the bottom surface changing unit 21 is set as the lowered position. As shown in FIG. 5A, the culture solution or the like is stored in the storage unit 3 and the algae is cultured so that the height of the liquid level of the culture solution or the like becomes h ₁ . The amount of the culture solution or the like at this time corresponds to the first amount.

Next, the position of the bottom surface changing unit 21 is set as the raised position. Further, as shown in Figure 5B, the height of the liquid level of the culture solution or the like to add a culture solution or the like so that h _2. In this state, the algae are cultured. The amount of the culture solution or the like at this time corresponds to the second amount.

3. Effects exhibited by the culture tank 101 According to the second embodiment described in detail above, the effects (1A) to (1C) of the first embodiment described above are achieved, and the following effects are further achieved.

(2A) The lower space C ₁ is a portion where light is difficult to reach when the amount of the culture solution is large and the liquid level is high. Culture tank 101 by a raised position the position of the bottom surface modification unit 21, it is possible to fill the lower space C _1. For example, as the culture method described above, a number the amount of the culture solution or the like, when a high liquid level fills the lower space C ₁ by the bottom surface modification unit 21, using a culture solution or the like of the portion excluding the lower space C ₁ Algae can be cultured. By doing so, it is possible to reduce the ratio of portions where light is difficult to reach in a culture solution or the like used for culture. As a result, algae can be cultured more efficiently.
<Third Embodiment>
1. Differences from the First Embodiment Since the basic configuration of the third embodiment is the same as that of the first embodiment, the differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description is referred to.

  As shown in FIGS. 6A and 6B, the culture tank 201 includes a main body 202 and a bottom surface changing unit 23. The main body 202 has a shape in which a horizontal hole 25 penetrating one side surface is formed in the main body 2 in the first embodiment.

  The bottom surface changing unit 23 is a flat plate member. The bottom surface changing unit 23 is inserted into the lateral hole 25 from the side. The bottom surface changing unit 23 is movable in the horizontal direction. The bottom surface changing unit 23 is movable between a retracted position shown in FIG. 6A and an approach position shown in FIG. 6B.

  When the bottom surface changing unit 23 is in the retracted position, the shape of the accommodating portion 3 is the same as the shape of the accommodating portion 3 in the first embodiment. The front end surface 213 of the bottom surface changing unit 23 is at the same position as the first side surface 13 in the first embodiment. Moreover, the part which has approached in the accommodating part 3 among the upper surfaces 209 of the bottom face change unit 23 exists in the same position as the 2nd bottom face 9 in 1st Embodiment. The first bottom surface 7 is not covered with the bottom surface changing unit 23. The position of the first bottom surface 7 corresponds to the first position.

When the bottom surface changing unit 23 is in the entry position, the front end surface 213 comes into contact with the first side surface 13 that faces the front surface. The lower space C ₁ is filled with the bottom surface changing unit 23, and the first bottom surface 7 is covered with the bottom surface changing unit 23. The bottom surface of the accommodating portion 3 is composed of an upper surface 209 and a second bottom surface 9 that are flush with each other. As the bottom surface changing unit 23 moves from the retracted position to the entering position, the central bottom surface in the housing portion 3 is changed from the first bottom surface 7 to the top surface 209. The upper surface 209 is above the first bottom surface 7. The position of the upper surface 209 corresponds to the second position.

2. Culture method Algae can be cultured using the culture tank 201 as follows. The position of the bottom surface changing unit 23 is set as the retracted position. As shown in FIG. 6A, the culture solution or the like is stored in the storage unit 3 and the algae is cultured so that the height of the liquid level of the culture solution or the like becomes h ₁ . The amount of the culture solution or the like at this time corresponds to the first amount.

Next, the position of the bottom surface changing unit 23 is set as the entry position. Further, as shown in FIG. 6B, the height of the liquid level of the culture solution or the like to add a culture solution or the like so that h _2. In this state, the algae are cultured. The amount of the culture solution or the like at this time corresponds to the second amount.

3. Effects exhibited by the culture tank 201 According to the third embodiment described in detail above, the effects (1A) to (1C) of the first embodiment described above are achieved, and the following effects are further achieved.

(3A) The lower space C ₁ is a portion where light is difficult to reach when the amount of the culture solution is large and the liquid level is high. Culture tank 201 by the entry position the position of the bottom surface modification unit 23, it is possible to fill the lower space C _1. For example, as the culture method described above, a number the amount of the culture solution or the like, when a high liquid level fills the lower space C ₁ by the bottom surface modification unit 23, using a culture solution or the like of the portion excluding the lower space C ₁ Algae can be cultured. By doing so, it is possible to reduce the ratio of portions where light is difficult to reach in a culture solution or the like used for culture. As a result, algae can be cultured more efficiently.
<Fourth embodiment>
1. Differences from the First Embodiment Since the basic configuration of the fourth embodiment is the same as that of the first embodiment, the differences will be described below. Note that the same reference numerals as those in the first embodiment indicate the same configuration, and the preceding description is referred to. The culture tank 301 includes a main body 302 shown in FIGS. As shown in FIGS. 7 and 8, the accommodating portion 3 in the main body portion 302 includes a first inclined surface 27 and a second inclined surface 29. The first inclined surface 27 and the second inclined surface 29 are flat surfaces. The first inclined surface 27 and the second inclined surface 29 constitute a V-shaped valley in the vertical cross section.

The opening area of the accommodating part 3 in a horizontal section is so large that it goes upwards. For example, as shown in FIG. 8A, the opening area of the housing part 3 in the horizontal cross section in which the height from the bottom 19 of the main body 302 is h ₁ is S ₁ and the height from the bottom 19 is h _2. the opening area of the housing portion 3 in the cross section and S _2. h ₂ is larger than h ₁ . Opening area _{S 2} than the opening area _{S 1} is large. In addition, the whole accommodating part 3 respond | corresponds to an enlarged part.

As shown in FIGS. 7 and 8B, the sealing member 5 can be bridged between the first inclined surface 27 and the second inclined surface 29. At this time, the sealing member 5 seals the lower space C ₁ below the sealing member 5 in the internal space C. The sealing member 5 can also be removed from the main body 302.

2. First Culture Method Using the culture tank 301, algae can be cultured as follows. The sealing member 5 is removed from the main body 302. The culture solution or the like is stored in the storage unit 3 and the algae is cultured so that the height of the liquid level of the culture solution or the like becomes h ₁ . The amount of the culture solution or the like at this time corresponds to the first amount. Next, a culture solution or the like is added so that the height of the liquid surface of the culture solution or the like becomes h ₂ , and algae are further cultured. The amount of the culture solution or the like at this time corresponds to the second amount. Next, a culture solution or the like is added so that the height of the culture solution or the like becomes h ₃ , and algae are further cultured.

3. Second culture method Algae can be cultured using the culture tank 301 as follows. The sealing member 5 is removed from the main body 302. The culture solution or the like is stored in the storage unit 3 and the algae is cultured so that the height of the liquid level of the culture solution or the like becomes h ₁ . The amount of the culture solution or the like at this time corresponds to the first amount. Next, the sealing member 5 is attached at the position described above. Next, the height of the liquid level of the culture solution or the like to add a culture solution or the like so that h _2. In this case, the lower space C ₁ takes out the culture solution or the like may be a condition of the air may be a state in which the culture liquid or the like is accommodated. Next, the algae are cultured using a culture solution or the like above the sealing member 5. The amount of the culture solution or the like above the sealing member 5 corresponds to the second amount.

4). Effects produced by the culture tank 301
According to the fourth embodiment described in detail above, the effects (1A), (1B), and (1D) of the first embodiment described above are achieved, and the following effects are further achieved.

(4A) The accommodating part 3 has the form of an inclined surface in a vertical cross section. Therefore, the configuration of the culture tank 301 can be simplified.
<Fifth Embodiment>
1. Configuration of Culture Tank 401 The configuration of the culture tank 401 will be described with reference to FIG. The culture tank 401 is a raceway type tank. The culture tank 401 includes a main body portion 402 and a sealing member 405. The main body 402 includes a partition plate 31 in the center of the housing 3. The culture solution or the like stored in the storage unit 3 can circulate through the flow path 33 around the partition plate 31. Hereinafter, the direction in which the culture solution or the like flows through the flow path 33 is defined as a flow direction F.

  The accommodating portion 3 includes a first bottom surface 407, a pair of second bottom surfaces 409, a first side surface 413, and a second side surface 415. The first bottom surface 407 is located at the center of the flow path 33 in a direction orthogonal to the flow direction F (hereinafter referred to as an orthogonal direction). The first bottom surface 407 is continuous over the entire flow path 33 along the flow direction F.

  The pair of second bottom surfaces 409 are located on both sides of the first bottom surface 407 in the orthogonal direction. The second bottom surface 409 is continuous along the flow direction F over the entire flow path 33. The second bottom surface 409 is shallower than the first bottom surface 407.

  The first side surface 413 connects the end of the first bottom surface 407 and the end of the second bottom surface 409. The second side surface 415 is erected on the outer peripheral end of the second bottom surface 409 and reaches the upper end of the main body portion 402.

An internal space C exists inside the housing 3. The upper part of the housing part 3 is open, and the internal space C communicates with the outside above.
As shown in FIG. 9B, in the vertical cross section, the first bottom surface 407, the second bottom surface 409, the first side surface 413, the second side surface 415, and the partition plate 31 have a stepped shape.

The opening area of the accommodating part 3 in a horizontal section is so large that it goes upwards. For example, as shown in FIG. 9B, the opening area of the accommodating portion 3 in the horizontal section where the height from the bottom 19 of the main body portion 402 is h ₁ is S _1, and the horizontal where the height from the bottom 19 is h _2. the opening area of the housing portion 3 in the cross section and S _2. h ₂ is larger than h ₁ . Opening area _{S 2} than the opening area _{S 1} is large. In addition, the whole accommodating part 3 respond | corresponds to an enlarged part.

The sealing member 405 is a plate-like member having an annular shape in plan view. As shown in FIG. 9B, the sealing member 405 can be bridged on a pair of second bottom surfaces 409 facing each other with the first bottom surface 407 interposed therebetween. At this time, the sealing member 405 seals the lower space C ₁ below the sealing member 405 in the internal space C. Lower space C _1, of the inner space C, and corresponds to a portion including the deepest. The sealing member 405 can also be removed from the main body 402.

2. First culture method Using the culture tank 401, algae can be cultured as follows. The sealing member 405 is removed from the main body 402. The culture solution or the like is stored in the storage unit 3 and the algae is cultured so that the height of the liquid level of the culture solution or the like becomes h ₁ . The amount of the culture solution or the like at this time corresponds to the first amount. Next, a culture solution or the like is added so that the height of the liquid surface of the culture solution or the like becomes h ₂ , and algae are further cultured. The amount of the culture solution or the like at this time corresponds to the second amount.

3. Second culture method Using the culture tank 401, algae can be cultured as follows. The sealing member 405 is removed from the main body 402. The culture solution or the like is stored in the storage unit 3 and the algae is cultured so that the height of the liquid level of the culture solution or the like becomes h ₁ . The amount of the culture solution or the like at this time corresponds to the first amount. Next, the sealing member 405 is attached at the position described above. Next, the height of the liquid level of the culture solution or the like to add a culture solution or the like so that h _2. In this case, the lower space C ₁ takes out the culture solution or the like may be a condition of the air may be a state in which the culture liquid or the like is accommodated. Next, algae are cultured using a culture solution or the like above the sealing member 405 and the second bottom surface 409. The amount of the culture solution or the like above the sealing member 405 and the second bottom surface 409 corresponds to the second amount.

4). Effects produced by the culture tank 501
According to the fifth embodiment described in detail above, the effects (1A) to (1D) of the first embodiment described above are achieved.
<Other embodiments>
As mentioned above, although embodiment of this indication was described, this indication is not limited to the above-mentioned embodiment, and can carry out various modifications.

  (1) In 4th Embodiment, the recessed part 35 shown in FIG. The concave portion 35 falls below a surface obtained by extending the first inclined surface 27 and the second inclined surface 29. The bottom of the recess 35 is flat. For example, the culture solution or algae can be collected from the recess 35 after the culture is completed.

Moreover, as shown in FIG. 14, the recessed part 35 may be located in one side instead of the center in the left-right direction.
(2) In the fourth embodiment, the sealing member 5 shown in FIG. 11 may be provided. The sealing member 5 includes two rotating plates 37 and 39. An end portion of the rotation plate 37 is attached to the first inclined surface 27 so as to be rotatable about the rotation shaft 41. An end portion of the rotation plate 39 is attached to the second inclined surface 29 so as to be rotatable about the rotation shaft 43.

  The sealing member 5 can be in an open state shown in FIG. 11A and a closed state shown in FIG. 11B. In the open state, the entire lower surface of the rotating plate 37 is in contact with the first inclined surface 27, and the entire lower surface of the rotating plate 39 is in contact with the second inclined surface 29.

The closed state is a state in which the rotating plates 37 and 39 are rotated upward to constitute one plane. The sealing member 5 seals the lower space C ₁ below the sealing member 5 in the internal space C.

  (3) In the first to third embodiments, the number of steps in the step-like form seen in the vertical section is not particularly limited, and can be set as appropriate. For example, as shown in FIG. 12, a large number of stages may be provided.

  (4) In the second embodiment, a plurality of bottom surface changing units 21 may be provided. For example, the height of the second bottom surface 9 is changed by moving one bottom surface changing unit 21 in the vertical direction to change the height of the first bottom surface 7 and moving the other bottom surface changing unit 21 in the vertical direction. The height may be changed. For example, the first bottom surface 7, the second bottom surface 9, and the third bottom surface 11 can be flush with each other.

  (5) In each embodiment, the accommodating part may be provided with the part which is not an expansion part. In the portion that is not the enlarged portion, the opening area of the accommodating portion in the horizontal cross section is constant even when it is upward, or decreases as it goes upward.

(6) The main body 2 in the first embodiment may be as shown in FIG. The first bottom surface 7 is located not on the center in the left-right direction but on one side.
(7) A plurality of functions of one constituent element in the above embodiment may be realized by a plurality of constituent elements, or a single function of one constituent element may be realized by a plurality of constituent elements. . Further, a plurality of functions possessed by a plurality of constituent elements may be realized by one constituent element, or one function realized by a plurality of constituent elements may be realized by one constituent element. Moreover, you may abbreviate | omit a part of structure of the said embodiment. In addition, at least a part of the configuration of the above embodiment may be added to or replaced with the configuration of the other embodiment. In addition, all the aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

  (8) In addition to the culture tank described above, the present disclosure can be realized in various forms such as a system including the culture tank as a constituent element, a method for manufacturing the culture tank, and the like.

DESCRIPTION OF SYMBOLS 1, 101, 201, 301, 401, 501 ... Culture tank 2, 102, 202, 302, 402 ... Main part, 3 ... Storage part, 5, 405 ... Sealing member, 7 ... 1st bottom face, 9 ... 2nd Bottom surface, 11 ... third bottom surface, 13 ... first side surface, 15 ... second side surface, 17 ... third side surface, 19 ... bottom, 21, 23 ... bottom surface changing unit, 25 ... lateral hole, 27 ... first inclined surface, 29 2nd inclined surface, 31 ... Partition plate, 33 ... Channel, 35 ... Recess, 37, 39 ... Rotating plate, 41, 43 ... Rotating shaft, 107 ... Upper end surface, 209 ... Upper surface, 213 ... End surface, 407 ... first bottom surface, 409 ... second bottom surface, 413 ... first side surface, 415 ... second side surface, C ... internal space, C ₁ ... lower space

Claims (7)

A culture tank used for algae culture,
A storage unit that can store water or culture solution,
The said accommodating part is a culture tank which has an enlarged part where the opening area in a horizontal cross section becomes large, so that it goes upwards. The culture tank according to claim 1,
The enlarged portion is a culture tank having a stepped shape in a vertical cross section. The culture tank according to claim 1,
The expansion part is a culture tank having a shape of an inclined surface in a vertical section. The culture tank according to any one of claims 1 to 3,
A culture tank further comprising a sealing member that seals a part of the internal space of the housing part including the deepest part. The culture tank according to any one of claims 1 to 3,
A culture tank further comprising a bottom surface changing unit capable of changing at least a part of the position of the bottom surface of the housing portion between a first position and a second position above the first position.   An algae culture method for culturing algae using the culture tank according to any one of claims 1 to 5. A method for culturing algae according to claim 6,
Storing the first amount of water or culture solution in the storage unit and culturing the algae;
A method for culturing algae in which a second amount of water or a culture solution larger than the first amount is accommodated in the accommodating portion and the algae is cultured.

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