Porous structure, method for manufacturing porous structure, and apparatus for manufacturing porous structure

Abstract

To provide a technique that can reduce the environment load of a porous structure.SOLUTION: A porous structure has a plate-like shape with intertwined plant roots.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a porous structure, a method for manufacturing a porous structure, and an apparatus for manufacturing a porous structure. [Background technology]

[0002] Porous structures have been known for some time. For example, Patent Document 1 discloses a porous structure made of ceramics. Patent Document 2 discloses a technique for producing a porous structure from a thermoplastic resin. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-139400 [Patent Document 2] Japanese Patent Application Laid-Open No. 2015-101030 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even with the prior art such as Patent Documents 1 and 2, there is still room for improvement in the technology for reducing the environmental impact of porous structures. For example, the porous structure described in Patent Document 1 is made of ceramics and therefore does not decompose in the natural environment. As a result, after use, it must be crushed into small pieces by a crushing process or the like and then buried, which increases the environmental impact. In addition, the porous structure described in Patent Document 2 is made of a resin made from crude oil, so it does not decompose in the natural environment even if left unattended after use. Furthermore, when the resin is burned during disposal, combustion gases including carbon dioxide are emitted, which increases the environmental impact.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a technique for reducing the environmental load in porous structures. [Means for solving the problem]

[0006] The present invention has been made to solve at least part of the above-mentioned problems, and can be realized in the following aspects.

[0007] (1) According to one aspect of the present invention, there is provided a porous structure having a plate-like shape in which plant roots are intertwined with each other.

[0008] According to this configuration, the plate-shaped porous structure is formed by the intertwining of plant roots, which are organic matter. As a result, the porous structure is easily decomposed in the natural environment, so the impact on the environment caused by using the porous structure is small. Therefore, the environmental load can be reduced.

[0009] (2) In the porous structure of the above embodiment, the plants may be aquatic plants. According to this configuration, the porous structure has a plate-like shape in which the roots of the aquatic plants are intertwined with each other. This allows the porous structure to be produced by hydroponic cultivation. Therefore, it is not affected by environmental changes and can be produced stably in large quantities.

[0010] (3) In the porous structure of the above embodiment, the plants may have portions of their stems cut off. According to this configuration, the porous structure has a plate-like shape formed by the roots of the plants having their stems cut off and intertwining with each other. This allows the porous structure to have a desired shape due to the roots of the plants.

[0011] (4) According to another aspect of the present invention, there is provided a method for manufacturing a porous structure. This method for manufacturing a porous structure includes a first step of growing plant roots between a pair of opposing members placed in a liquid in an aquarium, and a second step of removing the plant roots grown in the first step from between the pair of members. According to this configuration, the method for manufacturing a porous structure produces a porous structure having a plate-like shape by growing plant roots between the pair of members placed in the liquid. In this way, the porous structure can be produced by hydroponic cultivation, and therefore can be produced stably and in large quantities without being affected by environmental changes.

[0012] (5) In the method for manufacturing a porous structure according to the above aspect, in the second step, the pair of members may be removed from the water tank together with the roots of the plant, and then the roots of the plant may be removed from between the pair of members. According to this configuration, the pair of members are configured to be detachable from the water tank. As a result, the porous structure can be manufactured by removing the porous structure together with the pair of members from the water tank and then detaching the pair of members from the porous structure, which makes it easy to manufacture the porous structure.

[0013] (6) The method for manufacturing a porous structure of the above aspect may include a third step of cutting off a portion of the stem of the plant grown in the first step. According to this configuration, in the third step, the portion of the plant stem that has grown between the pair of members and has a plate-like shape with intertwined roots of the plant can be used. This allows the shape of the porous structure to be formed into a desired shape.

[0014] (7) According to yet another aspect of the present invention, there is provided an apparatus for manufacturing a porous structure. This apparatus for manufacturing a porous structure includes a water tank for storing a liquid, and a formwork that is at least partially placed in the liquid in the water tank and that restricts the growth direction of plant roots growing inside the formwork. According to this configuration, the apparatus for manufacturing a porous structure includes a formwork that restricts the growth direction of plant roots. This makes it possible to form a porous structure having a desired shape, which has a plate-like shape with plant roots intertwined with each other.

[0015] (8) In the porous structure manufacturing apparatus of the above aspect, the formwork may include a first member having a cylindrical shape, a second member having a storage portion for storing the first member, and a connector that connects the first member and the second member stored in the storage portion, the connector forming a gap between the first member and the storage portion through which plant roots can grow. According to this configuration, the formwork includes a connector that connects the first member having a cylindrical shape to the second member that stores the first member. The connector connects the first member and the second member so as to form a gap between the first member and the storage portion of the second member through which plant roots can grow. This makes it possible to manufacture a porous structure having a curved surface between the first member and the storage portion.

[0016] The present invention can be realized in various forms, such as a porous structure having a mass-like shape with plant roots intertwined, a porous structure carrying a substance that exhibits a specific function, a member including a porous structure, a method of using a porous structure, and the like. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a schematic diagram showing a schematic configuration of a porous structure according to a first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of a porous structure. [Figure 3] FIG. 1 is a schematic diagram showing the general configuration of a porous structure manufacturing apparatus. [Figure 4]FIG. 2 is a schematic diagram of a mold for manufacturing the porous structure of the first embodiment. [Figure 5] FIG. 2 is a schematic diagram showing an example of the installation of a form in a porous structure manufacturing apparatus. [Figure 6] FIG. 1 is a first diagram illustrating a method for manufacturing a porous structure. [Figure 7] FIG. 2 is a second diagram illustrating the method for manufacturing a porous structure. [Figure 8] FIG. 10 is a third diagram illustrating the method for manufacturing a porous structure. [Figure 9] FIG. 4 is a fourth diagram illustrating the method for manufacturing a porous structure. [Figure 10] FIG. 1 is a diagram illustrating an example of use of a porous structure. [Figure 11] FIG. 4 is a schematic diagram showing the general configuration of a porous structure according to a second embodiment. [Figure 12] FIG. 10 is a schematic diagram of a mold for manufacturing a porous structure according to a second embodiment. [Figure 13] FIG. 4 is a schematic diagram showing a modified example of the formwork of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] First Embodiment FIG. 1 is a schematic diagram showing the overall configuration of a porous structure of a first embodiment. FIG. 2 is a cross-sectional view of the porous structure of this embodiment, taken along line AA in FIG. 1. The porous structure 1 of this embodiment is a plant root structure formed by intertwining plant roots 5a. Specifically, as shown in the cross-sectional view of the porous structure 1 in FIG. 2, the porous structure 1 is a porous material having a predetermined shape due to the intertwining of plant roots 5a. In this embodiment, as shown in FIG. 1, the porous structure 1 has a substantially rectangular flat plate shape with the intertwining of aquatic plant roots 5a. Note that in each of FIGS. 1 and 2, the outline S5 indicating the outline of the porous structure 1 is indicated by a dotted line.

[0019] 3 is a schematic diagram showing the outline of the configuration of a porous structure manufacturing apparatus. Next, the manufacturing apparatus for the porous structure 1 will be described. The porous structure manufacturing apparatus 10 (hereinafter simply referred to as "manufacturing apparatus 10") includes a water tank 11, a formwork 20, a top cover 12, a planting panel 13, a tank 14, a pump 15, a compressor 16, and a distribution plate 17.

[0020] The water tank 11 stores a culture solution 11a for producing the porous structure 1 by hydroponic cultivation. The formwork 20 is placed in the water tank 11 so as to be immersed in the culture solution in the water tank 11. In this embodiment, the formwork 20 has a shape that allows it to be attached to and detached from the water tank 11.

[0021] FIG. 4 is a schematic diagram of a mold provided in the porous structure manufacturing apparatus of this embodiment. FIG. 4(a) is a front view of a flat plate member 21 provided in the mold 20, FIG. 4(b) is a plan view of the flat plate member 21, and FIG. 4(c) is a side view of the flat plate member 21. The flat plate member 21 shown in FIG. 4 is made of a material that does not corrode in the culture solution, such as acrylic, polycarbonate, or Teflon (registered trademark), and includes a plate portion 21a, an expanded portion 21b, and two engaging portions 21c. The plate portion 21a is formed in a flat plate shape and is positioned in the culture solution 11a when the mold 20 containing the culture solution 11a is placed in the water tank 11. The expanded portion 21b connected to the plate portion 21a is formed to have a width substantially the same as the width of the inside of the water tank 11. As a result, the expanded portion 21b comes into contact with the inside of the water tank 11 when the flat plate member 21 is placed in the water tank 11. The two engaging portions 21c are arranged to sandwich the widened portion 21b and are connected to the widened portion 21b.

[0022] Fig. 5 is a schematic diagram showing an example of the installation of a form in the porous structure manufacturing apparatus of this embodiment. Fig. 5(a) is a view from the front side of flat plate member 21, Fig. 5(b) is a view from above flat plate member 21, and Fig. 5(c) is a view from the side of flat plate member 21. As shown in Fig. 5(a), when flat plate member 21 is installed in water tank 11, engaging portion 21c is engaged with edge 11b on the opening side of water tank 11, so that flat plate member 21 is supported by water tank 11. At this time, as shown in Fig. 5(a), plate portion 21a is maintained spaced apart from inner bottom surface 11c and inner side surface 11d of water tank 11 inside water tank 11.

[0023] In this embodiment, as shown in Figures 5(b) and 5(c), flat plate members 21 are arranged in a row so that the distance d between a pair of flat plate members 21, each of which is a combination of two flat plate members 21, is equal to the thickness d of the porous structure 1 (see Figure 2). A form 20 made up of a pair of flat plate members 21 is open at a portion facing the inner bottom surface 11c of the water tank 11 and at a portion facing the inner side surface 11d. This allows the culture solution to easily flow into the form 20. In the method for manufacturing a porous structure of this embodiment, roots 5a of an aquatic plant are grown between the pair of flat plate members 21 to manufacture the porous structure 1.

[0024] 3, the top lid 12 is a substantially flat plate-shaped member. The top lid 12 is disposed so as to close the opening of the water tub 11.

[0025] The planting panel 13 is, for example, a sponge-like member made of synthetic resin, and is placed at the upper end of the formwork 20. In this embodiment, the planting panel 13 is fitted into a through-hole 13a formed in the upper cover 12, as shown in Fig. 3. Seeds of aquatic plants are sown in the planting panel 13 in the method for manufacturing a porous structure. As a result, in the method for manufacturing a porous structure, the stems of the aquatic plants grow above the planting panel 13, centered on the planting panel 13, while the roots grow below the planting panel 13 and inside the formwork 20.

[0026] The tank 14 stores the culture solution 11a in the water tank 11. The tank 14 and the water tank 11 are connected by flow path sections 14a and 14b. The flow path section 14a has a flow path for sending the culture solution 11a in the tank 14 to the water tank 11. The flow path section 14a has a filter 14c at its tip on the tank 14 side for removing foreign matter contained in the culture solution 11a in the tank 14. The flow path section 14a is provided with a pump 15 for sending the culture solution 11a in the tank 14 to the water tank 11. The flow path section 14b has a flow path for sending the culture solution 11a in the water tank 11 into the tank 14. The flow path section 14b has a valve 14d for controlling the flow of the culture solution 11a in the flow path of the flow path section 14b.

[0027] The compressor 16 is connected to the inside of the water tank 11 via the flow path section 16a. The compressor 16 pressurizes external air and injects the air into the culture solution 11a in the water tank 11. The flow path section 16a has a dispersion plate 17 made of a porous material at the end on the water tank 11 side. The dispersion plate 17 converts the air into fine bubbles. This allows the dispersion plate 17 to increase the dissolved oxygen concentration in the culture solution 11a in the water tank 11.

[0028] Next, a detailed description will be given of a method for manufacturing the porous structure 1 of this embodiment. The porous structure 1 of this embodiment is manufactured by submerged hydroponic cultivation, which is a type of hydroponic cultivation in which plants are grown using only a culture solution without using soil. Hydroponic cultivation has advantages such as suppressing the occurrence of plant diseases, stabilizing quality, and facilitating expansion of production scale, as it is easy to control the cultivation environment.

[0029] In the manufacturing method of the porous structure 1 of this embodiment, first, seeds of aquatic plants are sown in the planting panel 13. When the seeds sown in the planting panel 13 germinate, the roots 5a of the aquatic plants grow along the plate portions 21a of the flat plate members 21 between the pair of flat plate members 21 of the formwork 20. In other words, the growth direction of the roots 5a of the aquatic plants is restricted by the flat plate members 21. The roots 5a of the aquatic plants growing along the plate portions 21a of the flat plate members 21 grow so as to intertwine with each other.

[0030] 6 is a first diagram illustrating a method for manufacturing a porous structure. In the method for manufacturing a porous structure 1 of this embodiment, roots 5a of an aquatic plant 5 grow using dissolved oxygen in a culture solution 11a. The manufacturing apparatus 10 uses a compressor 16 to supply air into the culture solution 11a so that the dissolved oxygen concentration in the culture solution 11a reaches a level at which the aquatic plant 5 can grow (dotted arrow F1 in FIG. 6).

[0031] FIG. 7 is a second diagram illustrating the method for manufacturing a porous structure. As described above, if the dissolved oxygen concentration in the culture solution 11a is insufficient even when air is supplied using the compressor 16, the manufacturing apparatus 10 temporarily drains the culture solution 11a from the aquarium 11 into the tank 14 as shown in FIG. 7 (dotted arrow F2 in FIG. 7). This allows the roots 5a of the aquatic plants 5 to be exposed to air, thereby allowing the aquatic plants 5 to grow. After the roots 5a of the aquatic plants 5 have been sufficiently exposed to air, the manufacturing apparatus 10 uses the pump 15 to return the culture solution 11a from the tank 14 to the aquarium 11.

[0032] 8 is a third diagram illustrating the method for manufacturing a porous structure. When the roots 5a of the aquatic plants 5 have grown sufficiently in the manufacturing apparatus 10 and the porous structure 1 has been formed inside the formwork 20, the aquatic plants 5 are removed from the manufacturing apparatus 10. For example, as shown in FIG. 8, the aquatic plants 5 are removed from the manufacturing apparatus 10 together with the formwork 20 and the planting panel 13.

[0033] 9 is a fourth diagram illustrating a method for manufacturing a porous structure. The aquatic plant 5 removed from the manufacturing apparatus 10 is cut into roots 5a and stems 5b. For example, as shown in FIG. 9, first, a pair of flat plate members 21 are removed from the planting panel 13 to which the aquatic plant 5 is fixed (see FIG. 9(a)). After the pair of flat plate members 21 are removed from the planting panel 13, as shown in FIG. 9(b), the aquatic plant 5 is cut along the planting panel 13 (cutting line C1 in FIG. 9(b)) into roots 5a and stems 5b. As a result, the roots 5a formed in a flat plate shape are obtained, and the porous structure 1 is completed.

[0034] FIG. 10 illustrates an example of how a porous structure can be used. FIG. 10 illustrates a mulching material 1a covering a soil surface 91 of a field 90 as an example of how a flat porous structure 1 can be used. Mulching offers several benefits, including preventing the soil surface 91 of a field 90 where crops 8 are planted from drying out, reducing the impact of raindrops to prevent soil erosion, mitigating soil temperature changes by blocking sunlight, and preventing weed growth by blocking direct sunlight. Using a porous structure 1 formed from the roots 5a of aquatic plants 5 as mulching material 1a not only provides the aforementioned benefits of mulching, but is also easily decomposed by microorganisms in the natural environment after use. Because the mulching material 1a does not remain on the soil surface 91, it can reduce the environmental impact compared to mulching materials made from resin materials.

[0035] The use of the porous structure 1 of this embodiment is not limited to the mulching material described above. The porous structure 1 is formed in a porous shape by the intertwining roots 5a of the aquatic plants 5, and therefore has the function of retaining various substances. As a result, the porous structure 1 can be used for water purification, for example, by being submerged in a waterway such as a sewer and installed therein to collect foreign matter contained in the water flowing through the waterway. Furthermore, since the porous structure 1 is made of organic matter, even if the porous structure 1 with organic matter such as sludge attached thereto is used in a field by purifying water, residues are unlikely to be generated. This makes it possible to supply nutrients to agricultural crops in the field as fertilizer while reducing environmental impact.

[0036] Furthermore, as described above, the porous structure 1 is formed from organic matter, i.e., plant roots, and therefore has a relatively good affinity with other materials. As a result, by utilizing the porous structure 1's porous shape and relatively large specific surface area, various materials having specific functions can be supported, thereby forming a structure that exhibits the specific functions.

[0037] Furthermore, as described above, the porous structure 1 can be easily carbonized because it is made from organic matter, i.e., plant roots. The carbonized porous structure 1 can exhibit functions such as indoor humidity control, deodorization, and adsorption of harmful chemicals.

[0038] According to the porous structure 1 of this embodiment described above, the porous structure 1 having a flat plate shape is formed by the roots 5a of the aquatic plants 5, which are organic matter, intertwining with each other. As a result, the porous structure 1 is easily decomposed in the natural environment, and the impact on the environment caused by using the porous structure 1 is small. Therefore, the environmental load can be reduced.

[0039] Furthermore, according to the porous structure 1 of this embodiment, the porous structure 1 has a flat plate-like shape in which the roots 5a of the aquatic plants 5 are intertwined with each other. This allows the porous structure 1 to be produced by hydroponic cultivation. Therefore, it is not affected by environmental changes and can be produced stably in large quantities.

[0040] Furthermore, according to the porous structure 1 of this embodiment, the roots 5a of the aquatic plants 5 from which the stems 5b have been cut off are intertwined with each other, forming a flat plate-like shape in the porous structure 1. This allows the roots 5a of the aquatic plants 5 to form the desired shape of the porous structure 1.

[0041] According to the method for manufacturing the porous structure 1 of this embodiment, the roots 5a of the aquatic plants 5 are grown between a pair of flat plate members 21 placed in the culture solution 11a, thereby manufacturing the porous structure 1 having a flat plate shape. In this way, the porous structure 1 can be manufactured by hydroponic cultivation, and therefore can be manufactured in large quantities stably without being affected by environmental changes.

[0042] Furthermore, according to the manufacturing method of the porous structure 1 of this embodiment, the pair of flat plate members 21 have a configuration that allows them to be attached to and detached from the water tank 11. As a result, the porous structure 1 can be manufactured by removing the porous structure 1 together with the pair of flat plate members 21 from the water tank 11, and then removing the pair of flat plate members 21 from the porous structure 1, and therefore the porous structure 1 can be manufactured easily.

[0043] Furthermore, the manufacturing apparatus 10 of this embodiment includes a formwork 20 that restricts the growth direction of the roots 5a of the aquatic plants 5. This allows the manufacturing of a porous structure 1 having a flat plate-like shape in which the roots 5a of the aquatic plants 5 are intertwined with each other.

[0044] Second Embodiment 11 is a schematic diagram showing the general configuration of a porous structure according to the second embodiment. The porous structure 2 according to the second embodiment differs from the porous structure 1 according to the first embodiment (FIG. 1) in that it has an uneven curved surface shape.

[0045] The porous structure 2 of this embodiment is a plant root structure formed by intertwining roots 5a of aquatic plants 5. As shown in FIG. 11 , the porous structure 2 is a tubular member having a bottom, and includes a tubular circular pipe portion 2a and a bottom portion 2b connected to the end of the circular pipe portion 2a. In this embodiment, the circular pipe portion 2a has a convex outer surface 2c and a concave inner surface 2d. A through-hole 2e is formed in the center of the bottom portion 2b, connecting the inside and outside of the porous structure 2. The circular pipe portion 2a and the bottom portion 2b form a storage portion 2f in the porous structure 2 that can store an object. The porous structure 2 can be used as a seedling pot for growing seedlings by storing seedlings in the storage portion 2f, for example. When the porous structure 2 is used as a seedling pot, it is more easily decomposed in the natural environment than seedling pots made of resin film, eliminating the need for disposal after use. In FIG. 11, the outline S2 showing the outer shape of the porous structure 2 is indicated by a dotted line.

[0046] Fig. 12 is a schematic diagram of a mold for producing a porous structure of the second embodiment. Fig. 12(a) is a front view of the mold 30, and Fig. 12(b) is a plan view of the mold 30. The mold 30 has a cylindrical shape with a bottom, and includes a columnar member 31, a cylindrical member 32, two connecting portions 33, and two engaging portions 34.

[0047] The cylindrical member 31 is a cylindrical member arranged so that its axis coincides with the axis CA30 of the formwork 30. The cylindrical member 31 has a through-hole forming portion 31a at its bottom for forming the through-holes 2e in the porous structure 2.

[0048] The cylindrical member 32 is a member formed in a substantially cylindrical shape, and has an accommodation portion 32a therein that accommodates the columnar member 31. The cylindrical member 32 has a hole portion 32b at the bottom that connects the inside of the accommodation portion 32a with the outside of the formwork 30. The through-hole forming portion 31a of the columnar member 31 is inserted into the hole portion 32b.

[0049] 12(b), the two connecting portions 33 are connected at the top of the cylindrical member 31 so as to be disposed at diagonal positions with respect to the cylindrical member 31. The connecting portions 33 are formed to engage with the edges of the cylindrical member 32. As a result, a separation distance d corresponding to the thickness d of the porous structure 2 (see FIG. 11) is set between the cylindrical member 31 housed in the cylindrical member 32 and the cylindrical member 32.

[0050] 12(b), the two engaging portions 34 are connected at the top of the cylindrical member 32 so as to be diagonally positioned with respect to the cylindrical member 32 and at a 90-degree angle with respect to the two connecting portions 33. When the formwork 30 is placed in the water tank 11, the engaging portions 34 engage with the edge 11b of the water tank 11. This keeps the formwork 30 separated from the inner bottom surface 11c and inner side surface 11d of the water tank 11 inside the water tank 11.

[0051] When the porous structure 2 is manufactured using the formwork 30, seeds of the aquatic plants 5 are sown in the gap R1 between the columnar member 31 and the cylindrical member 32, which is shown by dotted hatching in FIG. 12(b). The aquatic plants 5 whose seeds have been sown in the gap R1 form a portion that will become the circular pipe portion 2a of the porous structure 2, and then form a portion that will become the bottom portion 2b. Once the porous structure 2 is formed in the formwork 30, the connection between the columnar member 31 and the cylindrical member 32 by the two connecting portions 33 is released, the formwork 30 is disassembled, and the porous structure 2 is removed. In this way, a cylindrical porous structure 2 having a bottom portion can be manufactured.

[0052] The porous structure 2 of this embodiment has a storage section 2f and is formed in a porous shape. As a result, the porous structure 2 has appropriate breathability, so by storing an object that requires ventilation, such as the seedling mentioned above, the object can be preserved in a state suitable for the object. Furthermore, because the storage section 2f has a recessed shape, foreign matter contained in a fluid (such as gas or liquid) injected into the storage section 2f can be collected by the circular pipe section 2a and the bottom section 2b, and the fluid can be purified.

[0053] According to the porous structure 1 of this embodiment described above, the formwork 30 includes a connecting portion 33 that connects the cylindrical member 31 having a cylindrical shape to the cylindrical member 32 that houses the cylindrical member 31. The connecting portion 33 connects the cylindrical member 31 and the cylindrical member 32 so as to form a gap R1 between the cylindrical member 31 and the housing portion 32a of the cylindrical member 32, allowing the roots 5a of the aquatic plants 5 to grow. This makes it possible to manufacture a porous structure 2 that has a curved surface between the cylindrical member 31 and the housing portion 32a.

[0054] <Modification of this embodiment> The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. For example, the following modifications are also possible.

[0055] [Variation 1] In the above-described embodiment, the plants forming the porous structure are aquatic plants 5 grown by hydroponics. However, the plants forming the porous structure are not limited to aquatic plants. Plants grown by hydroponics are preferred, but are not limited thereto.

[0056] [Variation 2] In the above embodiment, the plants forming the porous structure have been described as having their stems cut off, but the plants can also be used as porous structures with the stems still attached.

[0057] [Variation 3] In the above-described embodiment, in the method for manufacturing a porous structure, the plants grown in the aquarium are removed together with the formwork from the aquarium, and then the porous structure is removed from the formwork. However, the aquatic plants may be removed from the formwork while it is still installed in the aquarium.

[0058] [Variation 4] In the first embodiment, the flat-plate-shaped porous structure 1 is manufactured by growing roots 5a of the aquatic plants 5 between a pair of flat-plate members 21 placed in the culture solution 11a of the aquarium tank 11. However, the formwork for manufacturing the flat-plate-shaped porous structure 1 is not limited to this.

[0059] FIG. 13 is an explanatory diagram of a modified form for manufacturing the porous structure of the first embodiment. FIG. 13(a) is a front view of the form 40, FIG. 13(b) is a plan view of the form 40, and FIG. 13(c) is a side view of the form 40. The form 40 is a substantially box-shaped member and includes a pair of opposing plate portions 41, two connecting portions 42 connecting the pair of plate portions 41, and two engaging portions 43. The plate portions 41 have substantially the same shape as the combined shape of the plate portions 21a and the widened portion 21b of the flat plate member 21 described in FIG. 4. The connecting portions 42 connect the ends of the pair of plate portions 41 so that the distance d between the pair of plate portions 41 is equal to the thickness d of the porous structure 1. Two engaging portions 43 are provided on each of the two connecting portions 42. When the form 40 is placed in the water tank 11, the engaging portion 43 is engaged with the edge 11b of the water tank 11, thereby supporting the form 40 on the water tank 11. At this time, the form 40 is maintained inside the water tank 11, spaced apart from the inner bottom surface 11c and inner side surface 11d of the water tank 11. A flat-plate-shaped porous structure 1 can also be produced using the form 40 shown in FIG. 13.

[0060] [Variation 5] In the first embodiment, the porous structure 1 having a flat plate shape is manufactured by growing the roots of aquatic plants between a pair of flat plate members 21. In the second embodiment, the porous structure 2 having a cylindrical shape with a bottom is manufactured by growing the roots of aquatic plants between a columnar member 31 and a cylindrical member 32. The shape of the porous structure is not limited to this. For example, the porous structure may have a shape in which a plurality of flat plate shapes are connected, or may have a plate shape with convex shapes on both sides. Furthermore, a cylindrical mass porous structure may be manufactured by growing plant roots in a formwork formed only with cylindrical members 32. Alternatively, a polygonal cylindrical member may be used as a formwork instead of a cylindrical member to manufacture a polygonal columnar mass porous structure. Furthermore, a spherical shell-shaped member may be used as a formwork to manufacture a spherical mass porous structure.

[0061] This aspect has been described above based on embodiments and modifications. However, the above-described embodiments are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. Furthermore, if a technical feature is not described as essential in this specification, it may be deleted as appropriate. [Explanation of symbols]

[0062] 1,2...Porous structure 5…Aquatic plants 5a...root 5b...Stem 11...Aquarium 11a...Culture solution 20, 30, 40...formwork 21...Flat plate member 31...Cylindrical member 32...Cylindrical member 32a...Storage section 33...Connection 41...Plate part R1...Gap

Claims

1. A method for manufacturing a porous structure having a plate-like shape in which plant roots are intertwined with each other, comprising: a first step of growing plant roots between a pair of opposing members placed in a liquid in a tank; and a second step of removing the roots of the plant grown in the first step from between the pair of members. A method for producing a porous structure comprising the steps of:

2. A method for producing the porous structure according to claim 1, In the second step, the pair of members are removed from the liquid together with the roots of the plant, and then the pair of members are detached from the roots of the plant, and the roots of the plant are removed from between the pair of members. A method for producing a porous structure comprising the steps of:

3. The method for producing a porous structure according to claim 1 or claim 2 further comprises: A third step of cutting off a part of the stem of the plant grown in the first step is provided. A method for producing a porous structure comprising the steps of:

4. An apparatus for manufacturing a porous structure having a plate-like shape in which plant roots are intertwined with each other, a water tank for storing a liquid; a form that is placed in the liquid of the aquarium and that restricts the direction of root growth of plants growing inside the form; A porous structure manufacturing apparatus characterized by:

5. The porous structure manufacturing apparatus according to claim 4, The formwork is a first member having a cylindrical shape; a second member having a housing portion that houses the first member; a connection portion that connects the first member and the second member, The first member is accommodated in the accommodation portion with a gap between the first member and the second member for allowing roots of plants to grow. A porous structure manufacturing apparatus characterized by:

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