Hydroponic cultivation unit and hydroponic cultivation apparatus

Abstract

To provide a hydroponic cultivation unit capable of efficiently growing a plant while reducing maintenance effort.SOLUTION: Provided is a hydroponic cultivation unit used for hydroponic cultivation, comprising a bed and a panel, the bed having a bottom part and side parts rising to surround the bottom part, and the panel being either supported by the bed or floated on a nutrient solution stored in the bed. The panel is provided with a hole, through which a cultivated product is inserted, the hole extending vertically through the panel, and in at least a portion of a target wavelength region of 400 to 800 nm, the reflectance of an upper surface of the panel is greater than that of a lower surface of the panel, and the reflectance of an outer surface of the bed is greater than that of an inner surface of the bed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a hydroponic cultivation unit and a hydroponic cultivation device. [Background technology]

[0002] Patent Document 1 discloses a cultivation device for hydroponically cultivating plants. In this cultivation device, an irradiation device irradiates a cultivation tank that holds a culture solution for growing plants with light for growth, thereby promoting plant growth. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-23725 Summary of the Invention [Problem to be solved by the invention]

[0004] In a cultivation device such as that disclosed in Patent Document 1, it is desirable to grow plants efficiently while minimizing the maintenance work.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a hydroponic cultivation unit that can efficiently grow plants while reducing the maintenance effort. [Means for solving the problem]

[0006] According to the present invention, the following inventions are provided. [1] A hydroponic cultivation unit used for hydroponic cultivation, comprising a bed and a panel, wherein the bed has a bottom and sides that rise to surround the bottom, the panel is supported by the bed or floats in a nutrient solution contained in the bed, and the panel has holes through which the cultivated object is inserted that penetrate the panel in the vertical direction, and the reflectance of the upper surface of the panel is greater than the reflectance of the lower surface of the panel, and the reflectance of the outer surface of the bed is greater than the reflectance of the inner surface of the bed in at least a part of the target wavelength range of 400 to 800 nm. [2] The hydroponic cultivation unit according to [1], wherein the target wavelength range is a wavelength range of 400 to 800 nm. [3] The hydroponic cultivation unit according to [1] or [2], wherein the target wavelength range is one or both of a wavelength range of 400 to 500 nm and a wavelength range of 600 to 700 nm. [4] A hydroponic cultivation unit according to any one of [1] to [3], wherein the bed and the panel are each a resin molded body with a double-wall structure having a pair of walls spaced apart from each other. [5] A hydroponic cultivation unit according to [4], wherein the resin molded body is a molded body of first and second resin sheets made of resin compositions having different compositions. [6] A hydroponic cultivation device comprising a rack and a plurality of hydroponic cultivation units, wherein the hydroponic cultivation units are the hydroponic cultivation units described in any one of [1] to [5], the rack comprises a plurality of mounting sections arranged at a distance in the vertical direction, and each of the mounting sections is capable of mounting the hydroponic cultivation unit and is provided with a light source capable of irradiating the hydroponic cultivation units with light. [Effects of the Invention]

[0007] In the present invention, the reflectance of the upper surface of the panel is greater than the reflectance of the lower surface of the panel, and the reflectance of the outer surface of the bed is greater than the reflectance of the inner surface of the bed.

[0008] According to the above configuration, the reflectivity of the upper surface of the panel and the outer surface of the bed is relatively high, so that the light from the light source is reflected by the upper surface of the panel and the outer surface of the bed and is efficiently irradiated onto the plants, allowing the plants to grow efficiently.

[0009] Furthermore, with this configuration, the reflectivity of the underside of the panel and the inner surface of the bed is relatively low, which reduces the reflection of light that enters the nutrient solution and inhibits the growth of algae in the nutrient solution, thereby reducing the effort required for maintenance such as algae removal. [Brief explanation of the drawings]

[0010] [Figure 1] Fig. 1A is a configuration diagram of a hydroponic cultivation device 1 according to one embodiment of the present invention. Fig. 1B is a cross-sectional view taken along line BB in Fig. 1A. However, in Fig. 1B, the cultivated object 7 is not shown. [Figure 2] FIG. 1B is an enlarged view of region A in FIG. 1A. [Figure 3] FIG. 2 is a cross-sectional view of the hydroponic cultivation unit 3. [Figure 4] 3 is a cross-sectional view showing split molds 11a and 11b and resin sheets 12a and 12b that can be used to manufacture the bed 4. FIG. [Figure 5] 2 is a cross-sectional view showing split molds 13a and 13b and resin sheets 14a and 14b that can be used to manufacture panel 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] The following describes embodiments of the present invention. The various features shown in the following embodiments can be combined with each other. Furthermore, each feature can be an invention independently. Furthermore, in the following embodiments, elements not specified in the claims are optional elements and can be omitted. Any number of "0"s (for example, one or two) may be added to the end of numerical values ​​disclosed in the following description. For example, one or two "0"s may be added after "1.4" to make it "1.40" or "1.400."

[0012] 1. Hydroponic cultivation device 1 As shown in FIGS. 1 and 2, a hydroponic cultivation device 1 according to one embodiment of the present invention includes a rack 2 and a plurality of hydroponic cultivation units 3. The hydroponic cultivation units 3 will be described later. The rack 2 includes a plurality of mounting sections 2a. The mounting sections 2a are arranged spaced apart in the vertical direction. A top plate 2b is provided above the uppermost mounting section 2a. Each mounting section 2a and top plate 2b are supported by a support member 2c. A hydroponic cultivation unit 3 can be installed on each of the plurality of mounting sections 2a, and a light source 8 is provided that can irradiate light to the hydroponic cultivation units 3 placed on each mounting section 2a. With this configuration, the hydroponic cultivation units 3 are arranged in multiple stages, thereby increasing the amount of cultivation per unit area.

[0013] 1B, the placement portion 2a is composed of a plurality of rod-shaped members 2a1. In another example, the placement portion 2a is a roller conveyor, which makes it easy to move the hydroponic cultivation device 1 and reduces the labor required for planting and harvesting plants. In either case, the placement portion 2a has gaps through which light can pass.

[0014] The light sources 8 are fixed to the underside of the top plate 2b and to all of the placement sections 2a except the bottom one. This allows light to be emitted to the hydroponic cultivation units 3 placed below the light sources 8. The light L from the light sources 8 contains components with wavelengths suitable for plant growth. Generally, components in the wavelength range of 400 to 500 nm and components in the wavelength range of 600 to 700 nm are particularly important for plant growth. This is because the absorption spectrum of chlorophyll has peaks in these wavelength ranges. Therefore, it is preferable that the light from the light sources 8 contains components in one or both of the wavelength ranges of 400 to 500 nm and 600 to 700 nm.

[0015] Instead of providing the rack 2 with the top plate 2b, the light source 8 may be fixed to the ceiling of the building that houses the hydroponic cultivation device 1.

[0016] 2. Hydroponic Cultivation Unit 3 A hydroponic cultivation unit 3 used for hydroponic cultivation will be described with reference to Figures 1 to 3. The hydroponic cultivation unit 3 can be suitably used in the hydroponic cultivation device 1 described above. The hydroponic cultivation unit 3 includes a bed 4 and a panel 5. The bed 4 has a bottom 4c and side portions 4d that rise up to surround the bottom 4c and are capable of containing a nutrient solution 6. The panel 5 is supported by the bed 4 or floats in the nutrient solution 6 contained in the bed 4. The panel 5 is provided with a through-hole 5c that penetrates the panel 5 in the vertical direction, into which a cultivated object 7 is inserted. The cultivated object 7 includes a plant 7a to be cultivated and may include a fixing member 7b for easily fixing the plant 7a in the through-hole 5c. The fixing member 7b is preferably made of an elastic, deformable, and water-absorbent material such as a sponge. The plant 7a extends its roots through the through-hole 5c into the nutrient solution 6 and absorbs water and nutrients from the nutrient solution 6.

[0017] When performing hydroponic cultivation in the hydroponic cultivation device 1, it is necessary to move the panels 5 in order to plant or harvest the plants. Methods for moving the panels 5 include moving the panels 5 together with the bed 4, and moving only the panels 5 without moving the bed 4. Methods for moving only the panels 5 include removing the panels 5 from the bed 4 and moving them, and moving the panels 5 within the bed 4 while they are still stored in the bed 4. In the latter case, the bed 4 is preferably sized to allow the panels 5 to be moved within the bed 4, and more preferably to allow two or more (preferably three or more) panels 5 to be arranged in series.

[0018] In at least a part of the target wavelength range of 400 to 800 nm, the reflectance of the upper surface 5a of the panel 5 is greater than the reflectance of the lower surface 5b of the panel 5, and the reflectance of the outer surface 4b of the bed 4 is greater than the reflectance of the inner surface 4a of the bed 4. The reflectance in the target wavelength range is a simple average of the reflectances at all measured wavelengths in the total reflection spectrum of the target wavelength range. The inner surface of the container-shaped bed 4 is the inner surface of the bed 4, and the outer surface of the container-shaped bed 4 is the outer surface of the bed 4. In this embodiment, the inner surface 4c1 of the bottom 4c and the inner surface 4d1 of the side 4d are the inner surfaces of the bed 4, and the outer surface 4c2 of the bottom 4c and the outer surface 4d2 of the side 4d are the outer surfaces of the bed 4. When the bed 4 and the panel 5 are manufactured by the method described later in "3. Manufacturing method of the bed 4 and the panel 5," the upper surface 4d3 of the side portion 4d of the bed 4 has the same reflectivity as the inner surface 4d1 of the side portion 4d, and the side surface 5s of the panel 5 has the same reflectivity as the upper surface 5a in the portion above a parting line (not shown) formed on the parting surfaces of the split molds 13a, 13b, and the portion below the parting line has the same reflectivity as the lower surface 5b. It is preferable that the portion of the panel 5 that is immersed in the nutrient solution 6 has a low reflectivity, so it is preferable that the parting line is configured to be higher than the surface of the nutrient solution 6.

[0019] If there are multiple areas with different reflectances on the surface of the object to be measured, the reflectance can be calculated by adding up the value of [reflectance of each area x area ratio] for all areas. For example, if the area of ​​areas with a reflectance of 20% is 10% and the area of ​​areas with a reflectance of 80% is 90%, the reflectance of the surface to be measured is 20% x 0.1 + 80% x 0.9 = 74%.

[0020] According to the above configuration, the reflectivity of the upper surface 5a of the panel 5 and the outer surface 4b of the bed 4 is relatively high, so that the light from the light source 8 is more easily reflected by the upper surface 5a of the panel 5 and the outer surface 4b of the bed 4, and the light from the light source 8 is efficiently irradiated onto the plant 7a, allowing the plant 7a to grow efficiently.

[0021] Furthermore, with the above configuration, the reflectance of the lower surface 5b of the panel 5 and the inner surface 4a of the bed 4 is relatively low, which reduces the reflection of light that has entered the nutrient solution 6 and inhibits the growth of algae in the nutrient solution 6. This reduces the effort required for maintenance such as removing algae.

[0022] In other words, according to this embodiment, the portions of the panel 5 and the bed 4 that are exposed to the outside reflect light, thereby increasing the amount of light irradiated onto the plant 7a and promoting the growth of the plant 7a, while the portions of the panel 5 and the bed 4 that face the nutrient solution 6 are made less likely to reflect light, thereby suppressing the growth of algae in the nutrient solution 6.

[0023] Furthermore, as shown in FIG. 2 , when the hydroponic cultivation units 3 are arranged in multiple tiers and the light source 8 is arranged above each hydroponic cultivation unit 3, light from the light source 8L arranged above the lower hydroponic cultivation unit 3L travels both downward and upward, but the utilization efficiency of the upward light has been low in the past. On the other hand, in this embodiment, the hydroponic cultivation unit 3U is arranged above the light source 8L, and the reflectivity of the outer surface 4b of the bed 4 is high. Therefore, the light from the light source 8L traveling upward is reflected by the outer surface 4b and directed toward the hydroponic cultivation unit 3L, thereby improving the utilization efficiency of the light from the light source 8L. Thus, according to the configuration of this embodiment, when the hydroponic cultivation units 3 are arranged in multiple tiers and the light source 8 is arranged above each hydroponic cultivation unit 3, the utilization efficiency of the light from the light source 8 is further improved. This effect is particularly noticeable when the placement portion 2a is configured to allow light from the light source 8 to pass through.

[0024] The above effect is similarly achieved for all light sources 8 other than the uppermost light source 8 fixed to the tabletop 2b. For the uppermost light source 8, the efficiency of use of light from the light source 8 can be improved by, for example, increasing the reflectance of the underside of the tabletop 2b.

[0025] The target wavelength range is, for example, a wavelength range of 400 to 800 nm, which corresponds to the wavelength range of visible light, and therefore it is easy to intuitively recognize the reflectance of the panel 5 and the bed 4, for example, a white surface has a higher reflectance than a black surface.

[0026] The target wavelength range is one or both of the wavelength range of 400 to 500 nm and the wavelength range of 600 to 700 nm. As described above, light in these wavelength ranges is important for plant growth, and therefore, the effects of the present invention are more effectively achieved when the reflectances in these wavelength ranges satisfy the above-mentioned relationship.

[0027] The reflectance of the lower surface 5b of the panel 5 to the reflectance of the upper surface 5a is, for example, 0 to 0.8, and preferably 0 to 0.5. Specific examples of this value include 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8, and may be within a range between any two of the values ​​exemplified here. In other words, the lower surface 5b of the panel 5 is preferably a darker color than the upper surface 5a, and it is more preferable that the lower surface 5b is black and the upper surface 5a is gray or white.

[0028] The value of the reflectance of the inner surface 4a of the bed 4 to the reflectance of the outer surface 4b is, for example, 0 to 0.8, and preferably 0 to 0.5. Specific examples of this value are 0.0, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, and 0.8, and may be within a range between any two of the values ​​exemplified here. In other words, it is preferable that the inner surface 4a of the bed 4 is a darker color than the outer surface 4b, and it is even more preferable that the inner surface 4a is black and the outer surface 4b is gray or white.

[0029] The reflectance of the lower surface 5b and the inner surface 4a is, for example, 0 to 40%, specifically, for example, 0, 5, 10, 15, 20, 25, 30, 35, or 40%, or may be in a range between any two of the values ​​exemplified here.The reflectance of the upper surface 5a and the outer surface 4b is, for example, 60 to 100%, specifically, for example, 60, 65, 70, 75, 80, 85, 90, 95, or 100%, or may be in a range between any two of the values ​​exemplified here.

[0030] The bed 4 and the panel 5 are preferably each a resin molded body. The resin constituting the bed 4 and the panel 5 is preferably a thermoplastic resin such as polyolefin, and examples of polyolefin include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymer, and mixtures thereof. The reflectance of each surface constituting the bed 4 and the panel 5 can be changed by changing the type and content of the additives to be blended.

[0031] The bed 4 and the panel 5 are preferably resin molded bodies with a double-wall structure having a pair of walls spaced apart from each other. In this case, by forming one of the pair of walls from materials with different compositions, the reflectances of the inner surface 4a and the outer surface 4b and the upper surface 5a and the lower surface 5b can be made different from each other. The interior of the resin molded body may be hollow, or a core material may be provided.

[0032] 3. Manufacturing method of bed 4 and panel 5 As shown in FIG. 4, the bed 4 can be formed by molding a pair of resin sheets 12a, 12b using a pair of split molds 11a, 11b that can be opened and closed relative to each other. Examples of molding methods include blow molding, vacuum molding, and combinations thereof. As shown in FIG. 5, the panel 5 can be formed by molding a pair of resin sheets 14a, 14b using a pair of split molds 13a, 13b that can be opened and closed relative to each other. Examples of molding methods include blow molding, vacuum molding, and combinations thereof. The base resin constituting the resin sheets is preferably a thermoplastic resin such as polyolefin, and examples of polyolefin include low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene-propylene copolymer, and mixtures thereof.

[0033] The resin sheets 12b, 14a that form the upper surface 5a of the panel 5 and the outer surface 4b of the bed 4 are preferably formed by adding a white pigment such as titanium oxide or zinc oxide as an additive to a base resin. The resin sheets 12a, 14b that form the lower surface 5b of the panel 5 and the inner surface 4a of the bed 4 are preferably formed by adding a black pigment such as carbon as an additive to a base resin. The reflectance of each surface that forms the bed 4 and the panel 5 can be changed by changing the type and content of the additive blended into the base resin that forms the resin sheets. With this configuration, the desired reflectance can be achieved without performing post-processing after the bed 4 and the panel 5 are molded.

[0034] Furthermore, in order to reduce the amount of light that passes through the panel 5 or bed 4 and enters the nutrient solution 6, the panel 5 and bed 4 preferably have low light transmittance in the target wavelength range. The transmittance in the target wavelength range is the simple average of the transmittance at all measured wavelengths in the transmission spectrum of the target wavelength range. In order to reduce the transmittance, the panel 5 and bed 4 are preferably made of a material and color that is difficult to transmit light. In particular, the lower surface 5b of the panel 5 and the inner surface 4a of the bed 4 have a relatively low reflectance, so increasing the light absorption rate of the walls that make up these surfaces is particularly effective in reducing the amount of light that passes through the panel 5 or bed 4 and enters the nutrient solution 6.

[0035] The transmittance of the walls constituting each of the upper surface 5a, the lower surface 5b, the inner surface 4a, and the outer surface 4b is, for example, 0 to 40%, specifically, for example, 0, 5, 10, 15, 20, 25, 30, 35, or 40%, and may be within a range between any two of the numerical values ​​exemplified here. The transmittance of the panel 5 and the bed 4 (the proportion of light that passes through the panel 5 or the bed 4 and enters the nutrient solution 6) is, for example, 0 to 16%, and preferably 0 to 5%. Specific examples of this transmittance are 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, or 16%, and may be within a range between any two of the numerical values ​​exemplified here or less. [Explanation of symbols]

[0036] 1: Hydroponic cultivation equipment 2: Rack 2a: Placement section 2a1: Rod-shaped member 2b: Top plate 2c: Support member 3: Hydroponic cultivation unit 3L: Hydroponic cultivation unit 3U: Hydroponic cultivation unit 4: Bed 4a: Inner surface 4b: External surface 4c: Bottom 4c1: Inner surface 4c2: External surface 4d: Side 4d1: Inner 4d2: External surface 4d3:Top surface 5: Panel 5a:Top surface 5b: Bottom surface 5c: Through hole 5s: side 6: Nutrient solution 7: Cultivated products 7a :Plant 7b: Fixing member 8:Light source 8L:Light source 11a: Split mold 11b: Split mold 12a: Resin sheet 12b: Resin sheet 13a: Split mold 13b: Split mold 14a: Resin sheet 14b: Resin sheet L: light

Claims

1. A hydroponic cultivation unit used for hydroponic cultivation, It has a bed and a panel. The bed has a bottom and side portions that rise up to surround the bottom, The panel is supported by the bed or floats in a nutrient solution contained within the bed; The panel is provided with a hole through which the cultivated object is inserted, the hole penetrating the panel in the vertical direction, In at least a part of a target wavelength range of 400 to 800 nm, the reflectance of the upper surface of the panel is greater than the reflectance of the lower surface of the panel, and the reflectance of the outer surface of the bed is greater than the reflectance of the inner surface of the bed.

2. 2. The hydroponic cultivation unit of claim 1, The hydroponic cultivation unit, wherein the target wavelength range is a wavelength range of 400 to 800 nm.

3. 2. The hydroponic cultivation unit of claim 1, The target wavelength range is one or both of a wavelength range of 400 to 500 nm and a wavelength range of 600 to 700 nm.

4. 2. The hydroponic cultivation unit of claim 1, The hydroponic cultivation unit, wherein the bed and the panel are each a resin molded body with a double-wall structure having a pair of walls spaced apart from each other.

5. 5. The hydroponic cultivation unit according to claim 4, The resin molded body is a molded body of first and second resin sheets made of resin compositions having different compositions.

6. A hydroponic cultivation device comprising a rack and a plurality of hydroponic cultivation units, The hydroponic cultivation unit is the hydroponic cultivation unit according to any one of claims 1 to 5, The rack includes a plurality of placement sections spaced apart in the vertical direction, The hydroponic cultivation device, wherein the hydroponic cultivation unit can be placed on each of the plurality of placement sections, and a light source capable of irradiating the hydroponic cultivation unit with light is provided.

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