Hydroponic cultivation system

Abstract

To efficiently promote the growth of cultivated plants. [Solution] The hydroponic cultivation apparatus 100 comprises a pipe 11 with a first through-hole 11a and a second through-hole 11b, a planting medium 12 positioned to block the first through-hole 11a and into which the cultivated plants are planted, a nutrient solution supply unit 20 that flows nutrient solution through the pipe 11, and an application gas supply unit 30 that flows an application gas containing carbon dioxide through the pipe 11. The second through-hole 11b is provided near the first through-hole 11a so that the application gas is ejected towards the cultivated plants.

Description

Technical Field

[0001] The present invention relates to a hydroponic cultivation device.

Background Art

[0002] As this type of device, a device configured to supply nutrient solution and air to cultivated plants is known. For example, the device described in Patent Document 1 includes a seedbed pallet for accommodating plants and a cultivation container containing a nutrient solution in which the roots of the plants drawn out from the lower surface of the seedbed pallet are immersed. The thickness of the air layer between the water surface of the nutrient solution and the lower surface of the seedbed pallet is adjusted so that 10% or more and 30% or less of the total length of the plant roots are exposed to air, and air is forcibly sent into the air layer.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a configuration in which air is blown to the roots like the device of Patent Document 1 above, carbon dioxide in the blown air is difficult to be utilized for photosynthesis, and it is difficult to efficiently promote the growth of cultivated plants.

Means for Solving the Problems

[0005] A hydroponic cultivation device according to one aspect of the present invention includes a pipe having a first through-hole and a second through-hole, a planting medium arranged to block the first through-hole and in which cultivated plants are planted, a nutrient solution supply unit that flows a nutrient solution through the pipe, and a gas application supply unit that flows an application gas containing carbon dioxide through the pipe. The second through-hole is provided in the vicinity of the first through-hole so that the application gas jets toward the cultivated plants.

Effects of the Invention

[0006] According to the present invention, the growth of cultivated plants can be efficiently promoted. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic block diagram showing an example of the main components of a hydroponic cultivation apparatus according to an embodiment of the present invention. [Figure 2] A block diagram schematically showing an example of the control configuration of the hydroponic cultivation system shown in Figure 1. [Figure 3] A block diagram schematically showing an example of the main components of the application gas supply unit in Figure 1. [Figure 4A] Enlarged view of the cultivation layer in Figure 1. [Figure 4B] Cross-sectional view along the line IVB-IVB in Figure 4A. [Figure 5] This figure shows a modified example of the piping in Figure 4A, where the piping consists of a main body and a lid. [Figure 6] This figure shows a modified example where a gas flow path is provided on the inner surface of the pipe shown in Figure 5. [Figure 7] Figure 5 shows a modified example where a gas flow path is provided on the outer surface of the piping. [Figure 8A] This figure shows a modified example where a gas flow path is provided on the outer surface of the piping shown in Figure 4A. [Figure 8B] A cross-sectional view along the line VIIIB-VIIIB in Figure 8A. [Figure 9A] This figure shows a modified example where a partition is provided to surround the planting hole and application hole shown in Figure 4A. [Figure 9B] A cross-sectional view along the line IXB-IXB in Figure 9A. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to Figures 1 to 9B. The hydroponic cultivation apparatus according to the embodiment of the present invention supplies nutrient solution to cultivated plants so that nutrients are absorbed through the roots, and also supplies air so that carbon dioxide (CO2) is absorbed through the leaves. Below, an example of hydroponic cultivation in an indoor plant factory will be described in particular.

[0009] Figure 1 is a schematic block diagram showing an example of the main components of a hydroponic cultivation apparatus (hereinafter referred to as "apparatus") 100 according to an embodiment of the present invention. As shown in Figure 1, the apparatus 100 mainly comprises a cultivation layer 10 in which cultivated plants are planted, a nutrient solution supply unit 20 that supplies nutrient solution to the cultivated plants, and an application gas supply unit 30 that supplies application gas containing CO2 to the cultivated plants.

[0010] The cultivation layer 10 is placed on a horizontal surface such as a cultivation rack R. Multiple cultivation layers 10 may be provided on each tier of the cultivation rack R which has multiple tiers, and furthermore, multiple cultivation layers 10 may be provided on each tier. The cultivation rack R is equipped with an LED light source L that illuminates the plants planted in each cultivation layer 10. In the following, the vertical direction, which is the direction of gravity, and the length and width directions of the piping 11 are defined as shown in the figure.

[0011] The cultivation layer 10 comprises a pipe 11 and a planting medium 12. Planting holes 11a and application holes 11b are drilled in the upper surface of the pipe 11. The planting holes 11a are through holes that penetrate the upper surface of the pipe 11, and multiple holes are drilled along the length of the pipe 11. The size of the planting holes 11a and the spacing between each planting hole 11a and adjacent planting holes 11a are determined according to the size of the cultivated plants from planting to harvest.

[0012] The application holes 11b are provided near each planting hole 11a so that the application gas is ejected toward the underside of the leaves of the cultivated plant, where there are many stomata that take in CO2 necessary for photosynthesis. Multiple application holes 11b are provided radially from the planting hole 11a, for example. The size of the application holes 11b and the number of application holes 11b provided around each planting hole 11a are determined so that the application gas ejected through the application holes 11b can reach the underside of the leaves of the cultivated plant. In the example in Figure 1, the application holes 11b are through-holes that penetrate the upper surface of the pipe 11.

[0013] The planting medium 12 is composed of a sponge-like member having elasticity and flexibility such as foamed polyurethane, and is arranged so as to block the planting hole 11a in a state where the cultivated plant is planted. By arranging the planting medium 12 in the planting hole 11a, the cultivated plant is planted at the planting position of the pipe 11 (the position corresponding to the planting hole 11a). The planting medium 12 is removed from the planting position of the pipe 11 together with the cultivated plant at the time of harvesting the cultivated plant.

[0014] The nutrient solution supply unit 20 has circulation pumps connected to the lower part of the pipe 11 at both ends of the pipe 11 in the cultivation layer 10 through a nutrient solution flow path constituted by appropriate pipes, and continuously flows and circulates the nutrient solution from one end of the pipe 11 to the other end. When a plurality of cultivation layers 10 are provided on each stage of a cultivation rack R having a plurality of stages, one end of the pipe 11 in the uppermost cultivation layer 10 and the other end of the pipe 11 in the lowermost cultivation layer 10 are respectively connected to the nutrient solution supply unit 20 through a nutrient solution flow path. In addition, one end of the pipe 11 in each stage of the cultivation layer 10 and the other end of the pipe 11 in the cultivation layer 10 of the upper and lower stages thereof are respectively connected through a nutrient solution flow path. That is, the pipes 11 of the cultivation layers 10 provided in each of the plurality of stages are connected in series to the nutrient solution supply unit 20. When a plurality of cultivation layers 10 are provided in each stage, the pipes 11 of the plurality of cultivation layers 10 provided in each stage may be connected in parallel or in series to the nutrient solution supply unit 20.

[0015] The nutrient solution supply unit 20 (circulation pump) is controlled by a controller 50 (Figure 2) so that the liquid level position of the nutrient solution flowing through the pipe 11 in the cultivation layer 10 becomes a predetermined height. The nutrient solution supply unit 20 is connected to the lower part of the pipe 11 which is below the liquid level position of a predetermined height, and the nutrient solution discharged from the circulation pump of the nutrient solution supply unit 20 flows into the liquid layer where the nutrient solution flows at one end of the pipe 11 and flows out of the liquid layer at the other end of the pipe 11.

[0016] The application gas supply unit 30 is connected to the upper part of the pipe 11 at one end of the pipe 11 of each cultivation layer 10 via an application flow path constituted by appropriate piping, and continuously flows the application gas from one end to the other end of each pipe 11. That is, the pipes 11 of each cultivation layer 10 are connected in parallel to the application gas supply unit 30. In this case, the application gas supply unit 30 can supply the application gas with an appropriate flow rate and CO2 concentration to the pipes 11 of each cultivation layer 10.

[0017] Also, the direction in which the nutrient solution flows through the pipe 11 of each cultivation layer 10 and the direction in which the application gas flows are the same direction from one end to the other end of each pipe 11. In this case, the energy consumed for the nutrient solution supply unit 20 to flow the nutrient solution and the application gas supply unit 30 to flow the application gas can be suppressed. The application gas supply unit 30 is controlled by a controller 50 (Fig. 2) so that the flow rate and CO2 concentration of the application gas flowing through the pipe 11 of the cultivation layer 10 are within a predetermined range.

[0018] The application gas supply unit 30 is connected to the upper part of the pipe 11 above the liquid surface position at a predetermined height, and the application gas supplied from the application gas supply unit 30 flows into the gas layer above the liquid surface position at one end of the pipe 11. The gas layer in the pipe 11 communicates with the space above the pipe 11 through the application holes 11b, whereby the application gas flowing through the gas layer in the pipe 11 jets out into the upper space through the application holes 11b and is applied to the cultivated plants.

[0019] Fig. 2 is a block diagram schematically showing an example of the control configuration of the apparatus 100 in Fig. 1. As shown in Fig. 2, the apparatus 100 further includes an alarm 40, a controller 50, a level sensor 51, CO2 (partial pressure) sensors 52, 53, a light quantity sensor 54, and a temperature sensor 55.

[0020] The controller 50 is comprised of a computer including a processor such as a CPU, memory such as RAM and ROM, and other peripheral circuits. The controller 50 is connected to the nutrient solution supply unit 20, the application gas supply unit 30, the alarm 40, the level sensor 51, the CO2 sensors 52 and 53, the light intensity sensor 54, and the temperature sensor 55, respectively. The controller 50 controls the nutrient solution supply unit 20, the application gas supply unit 30, and the alarm 40 based on signals from the level sensor 51, the CO2 sensors 52 and 53, the light intensity sensor 54, and the temperature sensor 55.

[0021] The level sensor 51 is installed in the piping 11 of the cultivation layer 10 and detects the liquid level of the nutrient solution flowing through the piping 11. The controller 50 controls the nutrient solution supply unit 20 (circulation pump) so that the liquid level detected by the level sensor 51 reaches a predetermined height.

[0022] The CO2 sensor 52 is installed in the piping 11 of the cultivation layer 10 or in the application channel connecting the application gas supply unit 30 to the piping 11, and detects the CO2 concentration of the application gas flowing through the piping 11 or the application channel. The controller 50 controls the application gas supply unit 30 so that the CO2 concentration of the application gas detected by the CO2 sensor 52 falls within a predetermined range.

[0023] The CO2 sensor 53 and alarm 40 are installed around the cultivation rack R in the room where the device 100 is installed. The CO2 sensor 53 detects the CO2 concentration in the room. The alarm 40 has a warning light, buzzer, etc., and is configured to emit an alarm to notify of an abnormality in the indoor environment. When the CO2 concentration in the room detected by the CO2 sensor 53 exceeds a predetermined alarm threshold, the controller 50 controls the alarm 40 to emit an alarm and also controls the application gas supply unit 30 to stop the supply of application gas. This allows for early detection and notification even if the application gas leaks, ensuring the safety of workers in the room. In addition, stopping the application gas supply unit 30 and stopping the supply of application gas prevents the supply of excessive CO2.

[0024] The light intensity sensor 54 is installed around the cultivated plants, for example on the cultivation rack R in Figure 1, and detects the amount of light irradiated onto the cultivated plants. The light irradiated onto the cultivated plants includes light from the LED light source L, as well as light from indoor lighting and, if applicable, ambient light. The LED light source L is turned on when the plant factory is in operation (for example, about 16 hours a day) and turned off when the plant factory is not in operation. Until the amount of light irradiated onto the cultivated plants reaches the light saturation point, the more light there is, the more active the photosynthesis of the cultivated plants becomes, and the more CO2 is consumed by photosynthesis per unit time.

[0025] The controller 50 estimates the amount of CO2 consumed per unit time by photosynthesis in cultivated plants based on the light intensity detected by the light intensity sensor 54, calculates an appropriate CO2 concentration (concentration range) for the applied gas according to the estimation result, and controls the applied gas supply unit 30 according to the calculation result. By considering the amount of light irradiated to the cultivated plants, the amount of CO2 consumed by photosynthesis in cultivated plants can be accurately estimated, and an appropriate CO2 concentration for the applied gas can be accurately calculated. In addition, it is possible to prevent the CO2 supplied from the applied gas supply unit 30 from being wasted. The appropriate CO2 concentration for the applied gas is set according to the variety of cultivated plant, for example, to about 400 ppm to 1500 ppm.

[0026] The temperature sensor 55 is installed around the cultivation rack R in the room where the device 100 is installed, and detects the room temperature around the cultivated plants. Photosynthesis of cultivated plants is most active within the appropriate temperature range for each plant. The controller 50 may calculate the amount of CO2 consumed per unit time by photosynthesis of cultivated plants and the appropriate CO2 concentration of the applied gas based on the light intensity detected by the light intensity sensor 54 and the room temperature detected by the temperature sensor 55.

[0027] Photosynthesis in cultivated plants tends to be more active during the day, especially in the morning, than at night. The controller 50 may further consider the time of day to calculate the amount of CO2 consumed per unit time by photosynthesis in cultivated plants and the appropriate CO2 concentration of the applied gas.

[0028] Figure 3 is a schematic block diagram showing an example of the main components of the application gas supply unit 30. As shown in Figure 3, the application gas supply unit 30 is a DAC (Direct Air Capture) device that recovers CO2 from the ambient air (atmosphere) and has a thermal swing adsorption (TSA (Thermal Swing Adsorption)) device configured to increase the CO2 concentration in the air. The application gas supply unit 30 flows the air, whose CO2 concentration has been increased by the TSA device, as an application gas from one end to the other of the piping 11 in each cultivation layer 10.

[0029] The TSA device of the application gas supply unit 30 includes a plurality of (two in the illustrated example) adsorption units 31a, 31b, a blower 32, a plurality of (two in the illustrated example) heaters 33a, 33b, an airflow distribution mechanism 34, and flow path switching mechanisms 35a, 35b.

[0030] Each adsorption section 31a, 31b is provided with an adsorbent (or absorbent). The adsorbent is a solid material configured to adsorb (or absorb) CO2 at room temperature and pressure, and to desorb CO2 when heated. For example, porous materials such as zeolites, or amine-based solid absorbents in which amine compounds are supported on a suitable carrier can be used. The adsorbent is configured, for example, in granular form and filled into the adsorption sections 31a, 31b.

[0031] The blower 32 is connected to each of the adsorption units 31a and 31b and blows ambient air to each of the adsorption units 31a and 31b. In other words, the blower 32 accelerates the ambient air and supplies it to each of the adsorption units 31a and 31b at a higher flow rate. The blower 32 is controlled by the controller 50.

[0032] Heaters 33a and 33b are interposed between the blower 32 and each adsorption section 31a and 31b. When heaters 33a and 33b are on, the air blown from the blower 32 to each adsorption section 31a and 31b is heated, thereby raising the temperature of the adsorbent material in each adsorption section 31a and 31b. When heaters 33a and 33b are off, the air from the blower 32 is blown to each adsorption section 31a and 31b without being heated. Heaters 33a and 33b are controlled by the controller 50.

[0033] Each heater 33a and 33b is set to a temperature higher than the ambient temperature, which is room temperature (for example, around 20°C). The set temperatures of heaters 33a and 33b are adjusted so that the CO2 concentration of the air (applied gas) containing CO2 desorbed from the adsorbent in each adsorption unit 31a and 31b is appropriate for the amount of CO2 consumed per unit time by photosynthesis in the cultivated plants. More specifically, the set temperatures of heaters 33a and 33b are set considering the desorption characteristics of the adsorbent, the amount of available power, and the temperature range in which the adsorbent does not deteriorate, and are set to, for example, around 50°C to 90°C. Normally, in a plant factory, cultivated plants are irradiated with a constant amount of light from an LED light source L, so the CO2 concentration of the applied gas is mainly adjusted via the set temperatures of heaters 33a and 33b.

[0034] When heaters 33a and 33b are switched from the off state to the on state, the air blown from the blower 32 is heated from room temperature to the set temperature and flows to each adsorption section 31a and 31b, causing the temperature of the adsorbent material in each adsorption section 31a and 31b to rise. When heaters 33a and 33b are switched from the on state to the off state, the air blown from the blower 32 flows to each adsorption section 31a and 31b at room temperature without being heated, causing the temperature of the adsorbent material in each adsorption section 31a and 31b to fall.

[0035] The airflow distribution mechanism 34 is interposed between the blower 32 and the heaters 33a and 33b, and distributes the air blown from the blower 32 to the adsorption sections 31a and 31b via the heaters 33a and 33b. The airflow distribution mechanism 34 is controlled by the controller 50.

[0036] The flow path switching mechanisms 35a and 35b are composed of three-way valves and are interposed between the adsorption units 31a and 31b and the piping 11 of the cultivation layer 10. The flow path switching mechanisms 35a and 35b are controlled by the controller 50 and flow air with an increased CO2 concentration, including CO2 detached from the adsorbent material of the adsorption units 31a and 31b, into the piping 11 of the cultivation layer 10 as the application gas. Alternatively, air with a reduced CO2 concentration due to CO2 adsorption by the adsorbent material of the adsorption units 31a and 31b is released into the atmosphere.

[0037] The controller 50 controls each part of the application gas supply unit 30 to alternately switch the operating mode of the application gas supply unit 30 between a first mode in which adsorption occurs at the adsorption unit 31a and desorption occurs at the adsorption unit 31b, and a second mode in which desorption occurs at the adsorption unit 31a and adsorption occurs at the adsorption unit 31b.

[0038] In the first mode, the controller 50 turns off the heater 33a so that the adsorbent material in the adsorption section 31a reaches an adsorption temperature close to room temperature, and turns on the heater 33b so that the adsorbent material in the adsorption section 31b reaches a desorption temperature close to the set temperature of the heaters 33a and 33b. The controller 50 also controls the flow path switching mechanism 35a so that the air with reduced CO2 concentration due to CO2 adsorption in the adsorption section 31a is released into the atmosphere, and controls the flow path switching mechanism 35b so that the application gas containing CO2 desorbed in the adsorption section 31b flows into the piping 11 of the cultivation layer 10.

[0039] In the second mode, the controller 50 turns on the heater 33a so that the adsorbent in the adsorption section 31a reaches the desorption temperature, and turns off the heater 33b so that the adsorbent in the adsorption section 31b reaches the adsorption temperature. The controller 50 also controls the flow path switching mechanism 35a so that the application gas containing CO2 desorbed in the adsorption section 31a flows into the piping 11 of the cultivation layer 10, and controls the flow path switching mechanism 35b so that the air with reduced CO2 concentration due to CO2 adsorption in the adsorption section 31b is released into the atmosphere.

[0040] The controller 50 controls the blower 32 and the airflow distribution mechanism 34 to adjust the airflow rate of the air flowing to the adsorption-side adsorption sections 31a and 31b (adsorption-side airflow rate) and the airflow rate of the air flowing to the desorption-side adsorption sections 31a and 31b (desorption-side airflow rate, equivalent to the airflow rate of the applied gas). More specifically, it considers the balance between the amount of CO2 adsorbed and desorbed in the first and second modes, and adjusts the desorption-side airflow rate (for example, 5 m³). 3 (approximately 45 m / h) relative to the airflow rate on the adsorption side (e.g., 45 m / h) 3 The airflow distribution mechanism 34 is controlled so that the airflow rate (approximately / h) becomes 8 times or more (for example, approximately 9 times).

[0041] Furthermore, in order to ensure sufficient airflow of the application gas so that it can be ejected towards the cultivated plants through the application holes 11b (Figure 1), and to ensure sufficient flow velocity of the application gas flowing through the piping 11 of the cultivation layer 10, a sufficient airflow (for example, 50 m) is provided. 3 The blower 32 is controlled to have a flow rate of approximately 1 / h. If the flow velocity of the application gas flowing through the piping 11 of the cultivation layer 10 is insufficient, the flow velocity of the application gas flowing out from the application holes 11b will be insufficient, and the application gas will diffuse into the surrounding area instead of being ejected towards the cultivated plants above.

[0042] In this way, the application gas supply unit 30 can continuously supply application gas at an appropriate flow rate and CO2 concentration to the piping 11 of the cultivation layer 10 by adsorbing and desorbing CO2 using multiple adsorption units 31a and 31b. Furthermore, since the application gas supply unit 30 supplies the application gas to the piping 11 of the cultivation layer 10 on the spot without storing it, storage equipment is unnecessary, allowing the entire device to be made smaller and simpler, and reducing the cost of supplying application gas. Moreover, by utilizing ambient air, the entire device can be made even smaller and simpler. In addition, the device 100 can be operated at all times as needed, regardless of the supply status of the raw material gas.

[0043] Furthermore, the application gas supply unit 30 supplies application gas at an appropriate CO2 concentration corresponding to the amount of CO2 consumed by photosynthesis in the cultivated plants, thus preventing the waste of recovered CO2 and the energy consumed by the blower 32 and heaters 33a and 33b. It is also safe for workers around the cultivated plants. When using ambient air, the composition of the application gas is equivalent to that of the atmosphere, and it does not contain harmful components like when exhaust gas is used, making it safe.

[0044] Figure 4A is an enlarged view of the cultivation layer 10 in Figure 1, and Figure 4B is a cross-sectional view along the IVB-IVB line in Figure 4A. In the examples of Figures 1, 4A, and 4B, the application hole 11b is a through-hole that penetrates the upper surface of the pipe 11, connecting the air layer inside the pipe 11 with the space above the pipe 11. As a result, the application gas flowing through the air layer inside the pipe 11 is ejected into the space above through the application hole 11b. Because the application gas flows through the air layer inside the pipe 11 through which the nutrient solution flows, there is no need to provide separate piping for the application gas, allowing the entire device to be made compact and simple, and reducing the cost of laying piping.

[0045] As shown in Figures 4A and 4B, the vertical position of the outlet (outside the pipe 11) of the application hole 11b from which the application gas is ejected is higher the closer it is to the center in the width direction of the pipe 11, and lower the further it is from the center in the width direction. The upper limit position UL of the application hole 11b coincides with the position of the outlet of the application hole 11b located at the center in the width direction of the pipe 11, and coincides with the upper end position of the pipe 11. Similarly, the vertical position of the inlet (inside the pipe 11) of the application hole 11b is also higher the closer it is to the center in the width direction of the pipe 11, and lower the further it is from the center in the width direction. The gas-liquid interface (liquid level) between the gas layer through which the application gas flows and the liquid layer through which the nutrient solution flows is adjusted to be lower than the inlet of the application hole 11b furthest from the center in the width direction of the pipe 11.

[0046] Figure 5 shows a modified example of the pipe 11 in Figure 4A, where the pipe body 11 is composed of a pipe body 110 and a cover portion 111. As shown in Figure 5, the pipe body 110 is constructed by cutting out a portion of the pipe body 11 near the upper end, more specifically a portion of the upper surface of the pipe body 11, along the center of the pipe body 11 in the width direction, from one end to the other. The cover portion 111 is made of a material such as foamed polypropylene and is formed as a flat plate so that it can be detachably placed on the cutout portion of the pipe body 110.

[0047] The cover portion 111 forms the upper surface of the pipe 11, and the cover portion 111 has a planting hole 11a and an application hole 11b. Furthermore, a gas flow path 11c is formed inside the cover portion 111 along the length of the pipe 11, from one end to the other, through which the application gas flows. The gas flow path 11c has, for example, an annular flow path provided near each planting hole 11a, avoiding each planting hole 11a, and a connecting flow path that connects one end of the cover portion 111, which corresponds to one end of the pipe 11 to which the application gas is supplied from the application gas supply unit 30, to each annular flow path.

[0048] The application hole 11b connects the annular flow path of the gas flow path 11c with the space above the pipe 11 (lid portion 111), thereby allowing the application gas flowing through the gas flow path 11c inside the pipe 11 (lid portion 111) to be ejected into the space above through the application hole 11b. When the lid portion 111 is formed in the shape of a flat plate, the upper limit position UL of the application hole 11b coincides with the upper end position of the pipe 11 (upper surface of the lid portion 111).

[0049] In the example shown in Figure 5, the nutrient solution supply unit 20 is connected to the lower part of the pipe body 110 at both ends of the pipe 11, and flows the nutrient solution to fill the space between the pipe body 110 and the lid 111. The application gas supply unit 30 is connected to the gas flow path 11c (connecting flow path) of the lid 111 at one end of the pipe 11, and flows the application gas into the gas flow path 11c.

[0050] As a result, the application gas supplied from the application gas supply unit 30 to one end of the piping 11 flows into the gas flow path 11c from one end of the lid 111, flows from one end of the piping 11 to the other, bypassing the planting hole 11a, and is ejected into the space above through the application hole 11b. In this case as well, since the application gas flows into the gas flow path 11c within the piping 11 (lid 111) through which the nutrient solution flows, there is no need to provide separate piping for the application gas, allowing the entire device to be made compact and simple, and reducing the cost of laying piping.

[0051] Figure 6 shows a modified example in which a gas flow path 11c is provided on the inner surface of the pipe 11 in Figure 5, more specifically on the lower surface of the lid portion 111. The lid portion 111 in Figure 6 is made of a material such as stainless steel, is formed as a thin plate, and no flow path is formed inside. The lid portion 111 in Figure 6 is provided with a gas flow path forming portion 11d that protrudes downward from the lower surface (inner surface of the pipe 11), and a gas flow path 11c is formed between the lower surface of the lid portion 111 and the gas flow path forming portion 11d.

[0052] The application hole 11b in Figure 6 penetrates the upper surface (lid portion 111) of the pipe 11 (lid portion 111) to connect the gas flow path 11c (annular flow path) with the space above the pipe 11 (lid portion 111), and the application gas flowing through the gas flow path 11c is ejected into the space above through the application hole 11b. In this case as well, since the application gas flows through the gas flow path 11c provided in the pipe 11 through which the nutrient solution flows, there is no need to provide separate piping for the application gas, allowing the entire device to be made compact and simple, and reducing the cost of laying piping. The upper limit position UL of the application hole 11b in Figure 6 also coincides with the upper end position of the pipe 11 (upper surface of the lid portion 111), similar to Figure 5.

[0053] Figure 7 shows a modified example in which a gas flow path 11c is provided on the outer surface of the pipe 11 in Figure 5, more specifically on the upper surface of the lid portion 111. The lid portion 111 in Figure 7 is also made of a material such as stainless steel, and is formed as a thin plate, with no flow path formed inside. The lid portion 111 in Figure 7 is provided with a gas flow path forming portion 11d that protrudes upward from the upper surface (outer surface of the pipe 11), and a gas flow path 11c is formed between the upper surface of the lid portion 111 and the gas flow path forming portion 11d.

[0054] The application hole 11b in Figure 7 penetrates the upper surface of the gas channel forming section 11d so as to connect the gas channel 11c (annular channel) with the space above the pipe 11 (lid section 111, gas channel forming section 11d), and the application gas flowing through the gas channel 11c is ejected into the space above through the application hole 11b. In this case as well, since the application gas flows through the gas channel 11c provided in the pipe 11 through which the nutrient solution flows, there is no need to provide separate piping for the application gas, allowing the entire device to be made smaller and simpler, and reducing the cost of laying piping. Furthermore, the upper limit position UL of the application hole 11b in Figure 7 coincides with the upper surface position of the gas channel forming section 11d provided at the upper end of the pipe 11 (upper surface of the lid section 111), so the application gas can be supplied from a position even closer to the underside of the leaves of the cultivated plants.

[0055] Figure 8A shows a modified example in which a gas flow path 11c is provided on the outer surface of the pipe 11 in Figure 4A, and Figure 8B is a cross-sectional view along the line VIIIB-VIIIB in Figure 8A. In Figures 8A and 8B, the pipe 11 is provided with a gas flow path forming portion 11d that protrudes upward from the top surface (outer surface), and a gas flow path 11c is formed between the top surface of the pipe 11 and the gas flow path forming portion 11d.

[0056] In Figures 8A and 8B, the application holes 11b, similar to those in Figure 7, penetrate the upper surface of the gas flow path forming section 11d so as to connect the gas flow path 11c (annular flow path) with the space above the pipe 11 (gas flow path forming section 11d), and the application gas flowing through the gas flow path 11c is ejected into the space above through the application holes 11b. In this case as well, since the application gas flows through the gas flow path 11c provided in the pipe 11 through which the nutrient solution flows, there is no need to provide separate piping for the application gas, allowing the entire device to be made smaller and simpler, and reducing the cost of laying piping. Furthermore, the upper limit position UL of the application holes 11b in Figures 8A and 8B, similar to Figure 7, coincides with the upper surface position of the gas flow path forming section 11d provided at the upper end of the pipe 11, so that the application gas can be supplied from a position even closer to the underside of the leaves of the cultivated plants.

[0057] Figure 9A shows a modified example in which partition sections 13a and 13b are provided to surround the planting hole 11a and application hole 11b in Figure 4A, and Figure 9B is a cross-sectional view along the line IXB-IXB in Figure 9A. As shown in Figure 9A, the pipe 11 is provided with a pair of partition sections 13a at both ends of the pipe 11 along the width direction, and a pair of partition sections 13b are provided between the pair of partition sections 13a along the length direction.

[0058] The partition sections 13a and 13b are used in an upright position (in use) as shown by the solid line, and are housed in a position (in storage) that abuts against the piping 11 outside the planting hole 11a and application hole 11b, as shown by the dashed line. The partition sections 13a and 13b are provided with a sliding mechanism or a rotating mechanism, and are configured to switch between the in use state and the storage state by sliding or rotating. The height of the partition sections 13a and 13b is set so that the upper ends of the partition sections 13a and 13b in the in use state are above the upper limit position UL of the application hole 11b. The mounting position of the partition sections 13a and 13b to the piping 11 is set so that the upper ends of the partition sections 13a and 13b in the storage state are below the upper limit position UL of the application hole 11b.

[0059] By providing partitions 13a and 13b that surround the planting hole 11a and the application hole 11b, the diffusion of the application gas ejected from the application hole 11b outside the cultivation rack R (Figure 1) is suppressed, and the CO2 contained in the application gas can be efficiently absorbed by the leaves of the cultivated plants. Even when the room temperature is controlled using air conditioning equipment, using partitions 13a and 13b prevents the air conditioning airflow from stirring the air around the planting hole 11a and the application hole 11b, and effectively suppresses the diffusion of the application gas.

[0060] The partition sections 13a and 13b may be used at all times, or they may be retracted as needed when planting or harvesting cultivated plants. Switching between the use state and the retracted state of the partition sections 13a and 13b may be done manually by an operator, or it may be done automatically by controlling the partition sections 13a and 13b (actuators of the sliding mechanism and rotation mechanism) with the controller 50 (Figure 2). When the partition sections 13a and 13b are controlled by the controller 50, the partition sections 13a and 13b may be switched to the use state when the supply of application gas by the application gas supply unit 30 is started, and the partition sections 13a and 13b may be switched to the retracted state when the supply of application gas is stopped.

[0061] This embodiment can provide the following effects and advantages. (1) The apparatus 100 comprises a pipe 11 with a planting hole 11a and an application hole 11b drilled in it, a planting medium 12 positioned to block the planting hole 11a and into which the cultivated plants are planted, a nutrient solution supply unit 20 that flows nutrient solution through the pipe 11, and an application gas supply unit 30 that flows application gas containing CO2 through the pipe 11 (Figures 1 and 2). The application hole 11b is provided near the planting hole 11a so that the application gas is ejected towards the cultivated plants (Figures 1, 4A to 9B).

[0062] This allows for the supply of nutrient solution to cultivated plants via piping 11, enabling nutrient absorption through the roots, while simultaneously supplying application gas to allow CO2 absorption through the leaves, thereby efficiently promoting plant growth. Furthermore, there is no need to install separate piping for the application gas, allowing for a compact and simple overall system configuration, and reducing the cost associated with laying piping.

[0063] (2) The planting hole 11a and the application hole 11b are provided on the upper surface of the pipe 11, and the application hole 11b connects the air layer above the liquid level in the pipe 11 with the space above the pipe 11 (Figures 1, 4A, and 4B). The application gas supply unit 30 flows the application gas into the air layer (Figure 1). This makes it possible to supply the application gas from near the planting position of the cultivated plants toward the underside of the leaves of the cultivated plants, where there are many stomata that take in CO2 necessary for photosynthesis.

[0064] (3) The application gas supply unit 30 has a TSA device configured to increase the CO2 concentration in the air by having multiple adsorption units 1a, 1b, each having an adsorbent, and the air with the increased CO2 concentration by the TSA device is flowed into the piping 11 as application gas (Figure 3). In this case, since the application gas can be supplied to the piping 11 of the cultivation layer 10 on the spot without storage, storage equipment is not required, the entire device can be made smaller and simpler, and the cost of supplying application gas can be reduced. Furthermore, by using ambient air, the entire device can be made even smaller and simpler. In addition, the device 100 can be operated at all times as needed, regardless of the supply status of the raw material gas.

[0065] (4) The apparatus 100 is equipped with a plurality of pipes 11, and the plurality of pipes 11 are connected in parallel to the application gas supply unit 30 (Figures 1 and 3). In this case, the application gas can be supplied from the application gas supply unit 30 to the pipes 11 of each cultivation layer 10 at an appropriate flow rate and CO2 concentration.

[0066] (5) The direction in which the nutrient solution flows and the direction in which the applied gas flows are the same (Figure 1). In this case, the energy consumed by the nutrient solution supply unit 20 to flow the nutrient solution and the applied gas supply unit 30 to flow the applied gas can be reduced.

[0067] (6) The piping 11 is laid inside the room. The device 100 further includes a CO2 sensor 53 for detecting the CO2 concentration inside the room, and an alarm 40 that emits an alarm when the CO2 concentration detected by the CO2 sensor 53 exceeds an alarm threshold (Figure 2). In this case, even if the application gas leaks, it can be detected and reported early, ensuring the safety of workers inside the room. In addition, by stopping the application gas supply unit 30 and stopping the supply of the application gas, the supply of excessive CO2 can be prevented.

[0068] (7) The device 100 is further equipped with a light intensity sensor 54 that detects the amount of light irradiated onto the cultivated plants (Figure 2). The application gas supply unit 30 adjusts the CO2 concentration of the application gas based on the amount of light detected by the light intensity sensor 54. This makes it possible to accurately estimate the amount of CO2 consumed by photosynthesis in the cultivated plants and accurately calculate the appropriate CO2 concentration of the application gas, thereby preventing the CO2 supplied from the application gas supply unit 30 from being wasted.

[0069] (8) The application gas supply unit 30 adjusts the CO2 concentration of the application gas based on the time of day or the indoor temperature around the cultivated plants. This allows for a more accurate estimation of the amount of CO2 consumed by photosynthesis in the cultivated plants, a more accurate calculation of the appropriate CO2 concentration of the application gas, and a more reliable prevention of waste of CO2 supplied from the application gas supply unit 30.

[0070] In the above embodiment, as shown in Figure 3, an example was described in which the application gas supply unit 30 recovers CO2 from the ambient air (atmosphere) using TSA and flows it into the piping 11 of the cultivation layer 10. However, the application gas supply unit that flows application gas containing CO2 into the piping is not limited to this. For example, application gas containing CO2 recovered from exhaust gas may be flowed, or application gas containing CO2 recovered by other methods such as PSA (Pressure Swing Adsorption) may be flowed. Application gas containing CO2 that has been stored in advance may also be flowed.

[0071] The above description is merely an example, and the present invention is not limited by the embodiments and modifications described above, as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above embodiments and modifications, and to combine modifications with each other.

[0072] 10 Cultivation layer, 11 Piping, 11a Planting hole, 11b Application hole, 11c Gas flow path, 11d Gas flow path forming section, 12 Planting medium, 13a,13b Partition section, 20 Nutrient solution supply section, 30 Application gas supply section, 31a,31b Adsorption section, 32 Blower, 33a,33b Heater, 34 Air volume distribution mechanism, 35a,35b Flow path switching mechanism, 40 Alarm, 50 Controller, 51 Level sensor, 52,53 CO2 sensor, 54 Light intensity sensor, 55 Temperature sensor, 100 Hydroponic cultivation device (device), 110 Piping body, 111 Cover section, L LED light source, R Cultivation rack, UL Upper limit position

Claims

1. A pipe having a first through-hole and a second through-hole, A planting medium is provided, which is positioned to block the first through-hole and into which the cultivated plants are planted. A nutrient solution supply unit that flows nutrient solution through the aforementioned piping, The system includes an application gas supply unit that flows an application gas containing carbon dioxide through the aforementioned piping, The hydroponic cultivation apparatus is characterized in that the second through-hole is provided near the first through-hole so that the application gas is ejected toward the cultivated plants.

2. In the hydroponic cultivation apparatus described in claim 1, The first through-hole and the second through-hole are provided on the upper surface of the piping, The second through-hole communicates the air layer above the liquid level in the pipe with the space above the pipe. The application gas supply unit is characterized by flowing the application gas into the gas layer.

3. In the hydroponic cultivation apparatus according to claim 1 or 2, The hydroponic cultivation apparatus is characterized in that the application gas supply unit has a temperature swing adsorption device configured to increase the carbon dioxide concentration in the air by having a plurality of adsorption units, each having an adsorbent, and the air with the carbon dioxide concentration increased by the temperature swing adsorption device is flowed into the piping as the application gas.

4. In the hydroponic cultivation apparatus described in claim 3, The system comprises multiple of the aforementioned pipes, The hydroponic cultivation apparatus is characterized in that the plurality of pipes are connected in parallel to the application gas supply unit.

5. In the hydroponic cultivation apparatus described in claim 3, A hydroponic cultivation apparatus characterized in that the direction in which the nutrient solution flows and the direction in which the applied gas flows are in the same direction.

6. In the hydroponic cultivation apparatus described in claim 1, The aforementioned piping is laid inside the room, A concentration detection unit for detecting the carbon dioxide concentration in the room, A hydroponic cultivation apparatus further comprising an alarm that issues an alarm when the carbon dioxide concentration detected by the concentration detection unit exceeds a threshold.

7. In the hydroponic cultivation apparatus described in claim 1, The system further includes a light intensity detection unit that detects the amount of light irradiated onto the cultivated plants, The hydroponic cultivation apparatus is characterized in that the application gas supply unit adjusts the carbon dioxide concentration of the application gas based on the amount of light detected by the light intensity detection unit.

8. In the hydroponic cultivation apparatus according to claim 7, The hydroponic cultivation apparatus is characterized in that the application gas supply unit adjusts the carbon dioxide concentration of the application gas based on the time of day or the temperature around the cultivated plants.

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