Air-cultivation device

Abstract

To provide improved aeroponics systems that reduce or obviate the problems with known systems.SOLUTION: An aeroponics device is disclosed, comprising a cultivation bed tray 302 having a bottom 322 and at least two side walls 304, and a nebulizer for nebulizing a nutrient solution, the cultivation bed tray being able to hold a plant support at a position spaced from the bottom of the cultivation bed tray, the nebulizer being located at the bottom of the cultivation bed tray and comprising an ultrasonic transducer and a holder for holding the ultrasonic transducer. Also there is disclosed a method of producing a crop by using the aeroponics apparatus by either flowing the nutrient solution to the bottom of the cultivation bed tray to contact at least the roots of the crop or providing the nutrient solution to the bottom of the cultivation bed tray and nebulizing the nutrient solution such that the nebulized nutrient solution contacts at least the roots of the crop.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an aeroponic cultivation apparatus and a method of cultivating crops and other plants using such an aeroponic cultivation apparatus. [Background technology]

[0002] Hydroponics, or aeroponics, is a method of growing crops without soil. Aeroponics, in particular, offers the advantage of allowing crops to grow at high densities and rapidly.

[0003] Aeroponics systems provide water and nutrients to crops by spraying a nutrient-rich spray solution onto the roots, which are suspended below the plant support. The plants are supported by the plant support, with the leaves and crown extending above the plant support. In aeroponics systems, air is able to contact both the canopy and roots of the crop plants, so the crops grow with a rich supply of oxygen, carbon dioxide, water, and nutrients. Improved root aeration is one of the advantages of aeroponics over hydroponics.

[0004] The spray nutrient solution may be produced in a low-pressure system with a low-pressure pump delivering the nutrient solution through jets. Low-pressure systems are generally considered suitable only for home or demonstration aeroponic units, and not for large commercial aeroponic systems.

[0005] Japanese Patent Publication No. H03-1523 (JP H03 1523), Chinese Utility Model No. 205727459 (CN-A-205727459) and Chinese Utility Model No. 205584993 (CN-A-205584993) each disclose a home-scale aeroponic cultivation system.

[0006] Korean Patent Publication No. 2013-0074172 (KR-A-20130074172) discloses a small-scale multi-level system with an ultrasonic atomizer immersed in a liquid and an aerosol whose delivery to plant roots is facilitated by a fan.

[0007] US Patent No. 5,937,575 discloses an apparatus and method for stabilizing an ultrasonically generated nutrient mist (i.e., aerosol plume or mass). To eliminate sensitivity to the humidity and temperature of the intake air, the mist is recirculated from the growth chamber to a mist-generating reservoir. The chamber and reservoir are connected by a mist supply conduit and a mist return conduit, which form a mist circulation circuit. Recirculation eliminates the dependency of the mist density on the intake air humidity, stabilizing the amount of nutrients used.

[0008] Chinese Patent Application Publication No. 106508655 (CN-A- 106508655) and Chinese Patent Application Publication No. 106577245 (CN-A- 106577245) disclose an aeroponic cultivation method for Polygonatum odoratum, in which an ultrasonic sprayer is disposed under the field plant plate of an apparatus suspended in the space above the bottom of an aeroponic cultivation bucket.

[0009] US Pat. No. 5,136,804 (US Pat. No. 5,136,804) discloses a device having mist generated by a mist generator including conduit means for directing the generated mist towards a growing plot, a container for receiving a quantity of water, and an ultrasonic transducer located in the container and immersed in the water when received.

[0010] Korean Patent Publication No. 2014-0088760 (KR-A-2014 0088760) discloses an ultrasonic spray culture system in which sprayed nutrient solution can be uniformly supplied from a mist generation system through a mist conduit and fewer ultrasonic vibration modules are required.

[0011] Other disclosures also utilize ultrasonic fog or mist generators and mist or mist delivery conduits for delivering the mist to a growing plot. For example, Chinese Patent Application Publication No. 101803561 (CN-A-101803561), Chinese Patent Application Publication No. 105594578 (CN-A-105594578), Chinese Utility Model No. 2011393457 (CN-A-2011393457), Chinese Utility Model No. 204168859 (CN-A-204168859), Chinese Patent Application Publication No. 102845293 (CN-A-102845293), Chinese Utility Model No. 202197639 (CN-A-202197639) and Chinese Patent Application Publication No. 102870659 (CN-A-102870659).

[0012] Chinese Utility Model No. 201557432 (CN-A-201557432) discloses an aeroponic greenhouse in which an ultrasonic atomizer spray nozzle is located at the top of the greenhouse above the planting area. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Japan Special Publication No. 03-1523 [Patent Document 2] Chinese Utility Model No. 205727459 [Patent Document 3] Chinese Utility Model No. 205584993 [Patent Document 4] Korean Patent Publication No. 2013-0074172 [Patent Document 5] U.S. Patent No. 5,937,575 [Patent Document 6] Chinese Patent Application Publication No. 106508655 [Patent Document 7] Chinese Patent Application Publication No. 106577245 [Patent Document 8] U.S. Patent No. 5,136,804 [Patent Document 9] Korean Patent Publication No. 2014-0088760 [Patent Document 10] Chinese Patent Application Publication No. 101803561 [Patent Document 11] Chinese Patent Application Publication No. 105594578 [Patent Document 12] Chinese Utility Model No. 2011393457 [Patent Document 13] Chinese Utility Model No. 204168859 [Patent Document 14] Chinese Patent Application Publication No. 102845293 [Patent Document 15] Chinese Utility Model No. 202197639 [Patent Document 16] Chinese Patent Application Publication No. 102870659 [Patent Document 17] Chinese Utility Model No. 201557432 Summary of the Invention [Problem to be solved by the invention]

[0014] In commercial high-density, high-pressure aeroponic (HPA) cultivation, nutrient solution is delivered through spray nozzles using high-pressure pumps. The spray nozzles in high-pressure aeroponic equipment generally provide a wide spray pattern and are spaced at regular intervals along a pressurized supply line. The nutrient solution can be atomized into droplets of various size distributions depending on the operating pressure of the HPA system. Controlling droplet size at the equipment level is very difficult due to variations in nozzle quality and pressure drops in the supply lines. Controlling the amount of water and nutrients delivered to plant roots is controlled by the spray duration.

[0015] The high-velocity droplets generated by HPA systems can degrade fine root structure, and the resulting cellular debris can clog HPA nozzles. As a result, roots must be spaced far enough away from the nozzles. Because droplet blockage by roots (especially in dense root beds) can leave roots around the bed unwatered, HPA systems are designed with overlapping nozzle spray arcs. However, this increases costs, system complexity, and the number of failure points in the pressurized supply lines. The need for a relatively wide spray angle also means that growing beds in HPA systems must be relatively tall, reducing the achievable bed density.

[0016] HPA nozzles are particularly prone to clogging, which means HPA systems require complex water treatment and filtration or the use of particulate-free fresh water. This adds to the cost and complexity of HPA systems. Furthermore, each HPA nozzle tends to be positioned so that it can be switched on or off across the entire supply line (which may have many nozzles connected). Therefore, it is generally not possible to control specific parts of the growing area.

[0017] Therefore, there is a need for an improved aeroponic growing system that mitigates or obviates the problems of known systems.

[0018] The purpose of the present invention is to address this need. [Means for solving the problem]

[0019] Therefore, in a first aspect, the present invention provides an aeroponic cultivation device comprising: a tray (i.e., a cultivation bed tray) having a bottom and at least two side walls, the cultivation bed tray adapted to hold a plant support at a position spaced apart from the bottom of the cultivation bed tray (to form a root space); and a sprayer for spraying a nutrient solution, the sprayer being located at the bottom of the cultivation bed tray and comprising an ultrasonic transducer and a fixing part for fixing the ultrasonic transducer in a predetermined position.

[0020] The use of sprayers with ultrasonic transducers allows for control of droplet size and droplet velocity, which is advantageous as it allows for adapting and / or controlling the droplet size, aerosol (mist) density, or duration of aerosol (mist spray) application to the growing season, species, and health of the crops in the growing bed trays. The use of ultrasonic sprayers allows for shallower growing beds, increasing the efficiency of vertical space usage in aeroponics farms, resulting in higher yields per unit area.

[0021] The ultrasonic transducer may be placed at the bottom of the grow bed tray. The generated mist disperses as a creeping flow (horizontally and vertically) into the space between the solution surface and the plant support (i.e., the root space where the crop roots hang during use), allowing the bottom of the grow bed tray to be closer to the plant support than with an HPA system. Because mist generation is not due to a high-pressure system, root damage and nozzle clogging are significantly reduced or avoided, reducing equipment downtime.

[0022] In one preferred embodiment, one or more ultrasonic transducers may be attached to the bottom of the grow bed tray (i.e., undermounted). An undermounted ultrasonic transducer may be held in a holder so that the ultrasonic transducer is in contact with (and preferably pressurized against) the bottom of the grow bed tray. Generally, this arrangement provides that a single layer (usually a relatively thin single layer), such as a plastic or metal material, exists between the ultrasonic transducer and the nutrient solution during use. Preferably, the single layer (e.g., plastic or metal material) provides excellent acoustic transmission characteristics.

[0023] Undermounting is highly advantageous, especially in commercial installations with multiple ultrasonic transducers, because it improves access to the ultrasonic transducer and other components and reduces interference without shutting down all ultrasonic transducers / components within the grow bed. Furthermore, the undermounted mounting of the ultrasonic transducer aids in heat dissipation, which can reduce heat radiating into the root space and negatively impact plant root growth. Undermounting also significantly reduces or eliminates root debris interaction with the ultrasonic transducer, extending the life of the ultrasonic transducer and, as a result, significantly reducing cleaning needs, improving operational efficiency and reducing costs.

[0024] The ultrasonic transducer may be mounted in a holder that can be permanently attached to the grow bed tray. The holder preferably has a wipe-clean surface / interface. The ultrasonic transducer is preferably removable from the holder (e.g., can be screwed / pressed into place) without removing the holder from the grow bed tray.

[0025] The apparatus may also include one or more sprayer shields that shield the transducers from plant roots and otherwise protect the transducers when in use. The one or more sprayer shields may be formed on the bottom of the grow bed tray.

[0026] The holder and / or fixing part may be such that the interface between the transducer and the nutrient solution, in use, is formed of a plastic material (i.e., nutrient solution interface:plastic) or a metallic material (i.e., nutrient solution interface:metallic material). The fixing part may be provided by one or more of a mechanical fixing part and / or an adhesive fixing part, for example a threaded opening, an adhesive, a threaded spike, a bolt or a plastic fixing part.

[0027] In use, the roots of the crop are preferably suspended in the root space, and the nutrient solution may contact the roots of the crop as an aerosol of the nutrient solution in the air.

[0028] At different times during any drain / flow cycle that may be used during operation of the aeroponics device of the present invention, some of the plant's roots may be immersed in the nutrient solution, but generally the roots are not constantly immersed. Even when some of the roots are immersed, the remaining roots come into contact with the aerosol generated by the device. The amount of roots that may be periodically immersed in the nutrient solution generally depends on the type of crop and the time spent cultivating the crop (which is related to the size of the plant). However, during aeroponics operation, typically only a small portion of the root space (depending on the volume of the root space) is occupied by the nutrient solution. During operation of the aeroponics device of the present invention, plants grow aeroponically during the initial part of their growth phase, and aeroponics conditions accelerate growth. During later stages of growth, the plant's taproot may enter the primary water body (i.e., the nutrient solution), which may provide additional benefits, including improving the plant's resilience to water stress while the remaining roots benefit from aeroponics conditions.

[0029] Typically, microgreens (usually grown for 5-10 days before harvest) have only a small root volume (less than 10% by volume, often less than 5% by volume) periodically immersed in the nutrient solution. Leafy vegetables (e.g., pea seedlings and lettuce, typically grown for 4 weeks before harvest) may periodically have a larger portion of their root volume immersed in the nutrient solution, e.g., less than 50% by volume, usually less than 40% by volume. Leafy vegetable crops grown for longer periods, such as basil (grown for 3 months and periodically harvested), and fruit and root vegetable crops, may have a significant portion of their root volume (e.g., less than 70% by volume) periodically immersed in the nutrient solution. Thus, in use, 70% or less of the root volume of the crop may be periodically immersed in the liquid (e.g., nutrient solution), typically 50% or less of the root volume of the crop may be immersed in the liquid (e.g., nutrient solution), more typically 20% or less of the root volume of the crop may be immersed in the liquid (e.g., nutrient solution), and most typically 10% or less (e.g., 5%) of the root volume of the crop may be immersed in the liquid (e.g., nutrient solution).

[0030] In this device, adjusting the frequency of the ultrasonic transducer changes the size of the droplets. Adjusting the voltage changes the rate at which droplets are produced. Each ultrasonic transducer acting on a body of water produces a predictable droplet size distribution.

[0031] During use, droplets of nutrient solution are released from the water surface as a mist / aerosol and dispersed in all directions in the creeping flow of the bed. The device can provide droplet size control, typically producing droplets in the range of 1-100 μm in diameter.

[0032] The fasteners may comprise an adhesive, and may optionally comprise an epoxy adhesive and / or another suitable adhesive.

[0033] Preferably, the fastening portion is acoustically transparent.

[0034] In one embodiment, the ultrasonic transducer may be attached to the bottom of the grow bed tray using adhesive, and the sprayer therefore comprises a fixture including the transducer and adhesive. In this embodiment, it is preferred that the location on the bottom of the grow bed tray where the transducer is attached is at least partially acoustically transmissive.

[0035] The fixing part may comprise a holder, which may be detachable from the cultivation bed tray as required.

[0036] The ultrasonic transducer is also preferably detachable from the holder.

[0037] The holder is typically acoustically designed and may comprise a portion made of an acoustically transparent material (e.g., an acoustic lens).

[0038] To better control the droplet size or mist / aerosol flow growth, the device may include at least two ultrasonic transducers. In this case, one or each ultrasonic transducer may have a predetermined or different resonant frequency. The predetermined resonant frequency is preferably in the kilohertz to megahertz range, and may be 200 kHz to 100 MHz, since the droplet size in the generated aerosol becomes smaller at higher frequencies.

[0039] Preferably, each growing bed tray is equipped with multiple ultrasonic transducers. This is advantageous in that it improves the delivery of the aerosol to the roots during use. Each growing bed tray may be equipped with 2 to 48 ultrasonic transducers, preferably 4 to 36 ultrasonic transducers, and more preferably 6 to 24 ultrasonic transducers.

[0040] Where multiple ultrasound transducers are present, each ultrasound transducer may preferably be independently controllable, which is advantageous in commercial installations as it allows for greater control of growth conditions across each part of the apparatus.

[0041] The apparatus may further comprise one or more fans to circulate air and further improve uniform delivery of the aerosol to the roots.

[0042] Exemplary ultrasonic transducers may have resonant frequencies of approximately 600 kHz, 1.7 MHz, 2.4 MHz, and / or 3 MHz.

[0043] Typically, the or each ultrasonic transducer may be a piezoelectric transducer.

[0044] Advantageously, the device may further comprise a liquid port, which may function as a liquid inlet for allowing the nutrient solution to flow into the bottom of the growing bed tray, and may also function as a liquid outlet for allowing the liquid to flow out of the bottom of the growing bed tray. Alternatively, there may be a liquid inlet and a liquid outlet.

[0045] The bottom of the grow bed tray may be shaped to form at least one sump for collecting nutrient solution, with the sprayer being positioned above or within the sump, which may be advantageous as a relatively small amount of nutrient solution may cover the sprayer during use.

[0046] However, it is preferred that the bottom of the grow bed tray be substantially flat to reduce unwanted retention of plant material or other organic material and / or stagnant water. The bottom of the grow bed tray may be sloped (i.e., has a slope, usually a shallow slope) to improve drainage and cleaning of the nutrient solution.

[0047] Generally, the liquid port / inlet may be connectable to an inlet pipe connected to a reservoir, which holds the nutrient solution. The device typically further comprises a pump for pumping the nutrient solution from the reservoir to the liquid port / inlet. Thus, the device may further comprise one or more inlet pipes, a reservoir, and optionally at least one pump. The device may also comprise one or more valves, one or more filters, and / or a nutrient solution dosing system.

[0048] The nutrient solution may be a by-product of aquaculture (i.e., the raising of aquatic animals such as snails, fish, crayfish, or shrimp in tanks).

[0049] Preferably, the grow bed tray is adapted to hold the plant support spaced apart from the bottom of the grow bed tray by one or more supports located on the side walls of the grow bed tray. The grow bed tray may be adapted to hold the plant support spaced apart from the bottom of the grow bed tray by mechanical fixtures and / or the one or more supports may be formed by the shape of one or more side walls of the grow bed tray.

[0050] The grow bed tray may be modular. Thus, one or more side walls may be removable. The device may further include a grow bed tray attachment for attaching two or more grow bed trays together. One grow bed tray or multiple grow bed trays attached together may form a grow bed of the device.

[0051] A modular ultrasonically driven aeroponic grow bed system for commercial operation would be highly advantageous because it would enable aeroponic cultivation to be used to produce crops more efficiently and on a larger scale than previously achieved. In use, the apparatus may be such that grow bed trays, plant supports, and / or grow beds (i.e., a combination comprising at least one grow bed tray and at least one plant support) can be lifted and / or moved around the facility either manually or by an automated system.

[0052] It is useful to monitor growing conditions and crops using one or more sensors. The sensors can be moisture (e.g., relative humidity), light, oxygen, pH, temperature, carbon dioxide, and / or root density sensors (e.g., sensors that detect light transmission through the root bed). Accordingly, the device can further include one or more sensor fixtures for securing the sensors to the growing bed tray. The device can further include one or more sensors. The sensors can include, for example, one or more sensors that measure or detect weight / mass, surface tension, temperature, viscosity, water level, nutrient solution density, moisture (e.g., vapor pressure or relative humidity), light, oxygen, pH, gas composition, sound intensity, pressure (of the nutrient solution or gas phase), carbon dioxide, and / or root density. Particularly useful sensors include water level, temperature (of the gas and / or nutrient solution), and relative humidity. The one or more sensors can be secured to the sensor fixture. The device can, of course, have one or more of the same sensors associated with it to measure and / or detect ambient conditions and properties.

[0053] The device may include one or more lighting fixtures positioned on the top, sides, and / or bottom of the grow bed tray so that illumination is provided when the lighting device is installed.

[0054] The apparatus may further comprise a plant support. The plant support may comprise a plant support tray and / or a fibrous material (e.g., a fibrous mat). Other plant supports that may be suitable include plugs and / or pots. The plant support is generally removable.

[0055] The plant support tray may be made of a plastic material. The plant support tray may include a support for supporting the plants (and / or supporting pots for the plants). Such a support may include, for example, a plurality of openings in (and defined by) the bottom of the plant support tray. It is advantageous if each plant support tray is shaped such that the plant support trays are stackable for storage.

[0056] Thus, in use, the apparatus may include a plant support and a nutrient solution covering the sprayer. Once the crop is planted, the apparatus may include the crop in the plant support, the roots of the crop located in the space between the plant support and the bottom of the grow bed tray (i.e., the root space, which is usually an air space).

[0057] A significant advantage of the present invention is that it provides improved aeroponic and operational efficiency. In particular, mounting the sprayers to the bottom of the grow bed trays provides significant operational benefits by reducing equipment downtime and the need for equipment cleaning. Additionally, the apparatus (and method) of the present invention improves the accuracy of irrigation control to promote water conservation.

[0058] Accordingly, in a second aspect, the present invention provides a method for crop production, the method comprising the steps of: (a) providing an aeroponic cultivation apparatus according to the first aspect; b) providing a plant support spaced apart from the bottom of a cultivation bed; (c) providing a crop on the plant support; and either i) flowing a nutrient solution onto the bottom of the cultivation bed tray so as to contact at least the roots of the crop; and / or ii) providing a nutrient solution onto the bottom of the cultivation bed tray and spraying the nutrient solution so as to contact at least the roots of the crop.

[0059] Preferably, spraying the nutrient solution includes spraying the nutrient solution to provide a predetermined and / or controllable droplet size distribution. The droplet size distribution may include droplets having diameters ranging from 1 to 100 μm, preferably 5 to 80 μm. Droplet size can be measured by a number of methods, for example, by detecting the droplet size distribution using an optical microscope.

[0060] In one embodiment, the method may include providing one or more root density sensors to sense the density of the root bed, and spraying the nutrient solution at a predetermined resonant frequency to produce a predictable (and controllable) droplet size distribution corresponding to an optimal droplet size distribution for the root bed density.

[0061] The nutrient solution may be a by-product of aquaculture (i.e., the raising of aquatic animals such as snails, fish, crayfish, or shrimp in tanks).

[0062] Advantageously, the apparatus and methods of the present invention improve crop yields compared to known apparatus and methods.

[0063] Crops that may be suitable for the apparatus and methods of the present invention include, but are not limited to, salad crops (e.g., baby leaf lettuce, arugula, watercress), herbs (e.g., basil, coriander), scallions, root vegetables (e.g., carrots, radishes, wasabi), fruit crops (e.g., bell peppers, strawberries, tomatoes), and microgreens (e.g., radishes, peas, sunflowers, leeks).

[0064] As used herein, mist refers to an aerosol of liquid droplets (eg, an aqueous solution) in a gas (eg, air). [Brief explanation of the drawings]

[0065] Embodiments of the present invention will now be described with reference to the following figures. [Figure 1A] FIG. 1 is a perspective view of a two-tray growing bed apparatus of the present invention. [Figure 1B] FIG. 1 is a side view of a two-tray growing bed apparatus of the present invention. [Figure 1C] FIG. 1C is a cross-sectional view taken along line AA in FIG. 1B. [Figure 2A] FIG. 1 is a perspective view of a single tray growing bed apparatus of the present invention. [Figure 2B] FIG. 1 is a side view of a single tray growing bed apparatus of the present invention. [Figure 2C] FIG. 2C is a cross-sectional view taken along line BB in FIG. 2B. [Figure 3] 1 is a schematic diagram of an apparatus according to the present invention; [Figure 4] FIG. 1 is a perspective view of a growing bed (single growing bed tray) according to another embodiment of the present invention. [Figure 5] FIG. 1 is a partially exploded perspective view of a grow bed comprising two grow bed trays connected to each other. [Figure 6A] FIG. 6 is a perspective view of a plant support in the form of a plant support tray suitable for use in the grow bed shown in FIGS. 4 and 5. [Figure 6B] FIG. 6B is a perspective view of the ten plant support trays shown in FIG. 6A stacked for storage. [Figure 7] FIG. 1 is a perspective view of a ready-to-use aeroponic growing apparatus according to the present invention, comprising a rack-like arrangement of three growing beds, each having one growing bed tray and five plant support trays. DETAILED DESCRIPTION OF THE INVENTION

[0066] FIG. 1 illustrates a two-tray grow bed 2 of the present invention. The grow bed 2 includes two grow bed trays 4, 6, with the first grow bed tray 4 and the second grow bed tray 6 connected to each other at a connection 14 by a bottom connector 16 and a side connector 18. Each grow bed tray includes a side wall 8, an end wall 10, and a bottom 22. The bottom 22 has an outer shape that forms a sump 24 for collecting nutrient solution (not shown) and a sprayer port 12 for a sprayer 20 residing within the sump 24, so that the sprayer is conveniently covered with nutrient solution during use. As seen in detail in FIG. 1C, the sprayer 20 includes a sprayer holder having a lower sprayer holder portion 30 and an upper sprayer holder portion 28, and an ultrasonic transducer 29 comprising a piezoelectric disc. The sprayer holders 28, 29, and 30 are removably secured to the bottom of the grow bed tray at a sprayer interface 32 on the outer surface of the sprayer port 12.

[0067] The ultrasonic transducer 29 may have a resonant frequency in the kilohertz to megahertz range, such that the droplet size in the aerosol / mist produced is smaller at higher frequencies.

[0068] Each grow bed tray has supports (not shown) on the side walls 8 to hold a plant support (not shown) spaced from the bottom 22 of the grow bed tray 2 to form a root space 26 .

[0069] 2 shows a second embodiment of the apparatus according to the present invention, comprising a single grow bed tray 102 having a side wall 108 but no end walls (to facilitate connection to another grow bed tray, if necessary), and six sprayer ports 112 for holding sprayers 120 distributed across the bottom 122 of the grow bed tray, each having an undermounted ultrasonic transducer 129 held by a sprayer holder. Each sprayer comprises a lower sprayer holder portion 130, an upper sprayer holder portion 128, and an ultrasonic transducer 129 comprising a piezoelectric disc. The sprayer holders 128, 129, and 130 are removably secured to the bottom of the grow bed tray at sprayer interfaces 132 on the outer surfaces of the sprayer ports 112.

[0070] The ultrasonic transducer 129 may have a resonant frequency in the kilohertz to megahertz range (eg, 200 kHz to 100 MHz), with the droplet size of the aerosol / mist produced generally decreasing with increasing frequency.

[0071] The grow bed tray 102 has supports (not shown) on the side walls 108 to hold a plant support (not shown) spaced from the bottom 122 to form a root space 126 .

[0072] 3 is a schematic diagram of an apparatus according to the present invention. The grow bed of a monoculture bed tray 202 has side walls 210 with supports 237 that hold a plant support mat 236 on top of the bottom of the grow bed tray, forming a root bed space 226. Nutrient solution 234 bathes a sprayer holder 232 that holds an ultrasonic transducer 230. When the sprayer is activated, it produces a mist of nutrient solution 234 that is dispersed throughout the root bed space 226.

[0073] Nutrient solution 234 is supplied from a reservoir 248 via an inlet 238 and is supplied via a first conduit 246 , a low pressure pump 244 and a second conduit 242 .

[0074] Excess nutrient solution is removed via outlet 240 .

[0075] FIG. 4 shows a diagram of a grow bed according to another embodiment of the present invention, comprising a single grow bed tray 302 having side walls 308, end walls 310, and multiple sprayer shields 320 distributed over the bottom 322 of the grow bed tray, each with an ultrasonic transducer (not shown) mounted beneath the sprayer shield 320. The sprayer shields 320 shield the transducers from plant roots and otherwise protect them during use. The bottom 322 of the grow bed tray 302 is essentially flat, and there are no sharp angles on the inside of the grow bed tray 302 to further facilitate growth. The grow bed tray 302 includes liquid ports 312 for nutrient / wastewater inlet and outlet and a control panel 352.

[0076] FIG. 5 illustrates an aeroponic cultivation apparatus according to an embodiment of the present invention, comprising a grow bed 402 with two grow bed trays. The two grow bed trays can be connected to each other by removing the side wall 410 between them and using an attachment fixture (not shown). Multiple sprayer shields 420 are distributed across the bottom 422 of the grow bed trays, each having an ultrasonic transducer (not shown) mounted beneath the sprayer shield 420. The sprayer shields 420 shield the transducers from plant roots and otherwise protect the ultrasonic transducers during use. The bottom 422 of the grow bed trays is essentially flat and free of sharp edges, further facilitating cleaning. Each grow bed tray includes a control panel 452.

[0077] The ultrasonic transducer may be attached (i.e., undermounted) below the bottom of the grow bed tray and held in a holder so that the ultrasonic transducer contacts (preferably applies pressure to) the bottom of the grow bed tray. This arrangement typically results in, for example, a single layer (usually a relatively thin single layer) of plastic or metal material being present between the ultrasonic transducer and the nutrient solution during use. For example, a single layer of plastic or metal material provides excellent sound transmission properties.

[0078] The ultrasonic transducer may be mounted in a holder that may be permanently attached to the grow bed tray, the holder typically having a wipe-clean surface / interface, and the ultrasonic transducer may be detachable from the holder (e.g., screwed / pressurized without removing the holder).

[0079] Figure 6A shows a plant support in the form of a plant support tray 62 for use with the grow bed trays illustrated in Figures 4 and 5. The plant support tray 62 is of a plastic material and includes a bottom 64 with an opening 66 that acts as a support for the crop. The plant support tray 62 includes tall side walls 68, 70 and short side walls 72, 74. The tops of the tall side walls 68, 70 are shaped to allow convenient stacking with other plant support trays.

[0080] FIG. 6B shows multiple plant support trays 62 according to FIG. 6A stacked for storage.

[0081] 7 is a perspective view of an aeroponic cultivation apparatus according to the present invention, ready for use. The apparatus comprises a rack-like arrangement 501 of three growing beds 503, 504, 505, each having a growing bed tray 502 and five plant support trays 62. The growing beds 503, 504, 505 are supported on a shelf rack 507. Each growing bed 503, 504, 505 can be individually controlled by a control panel 552. Generally, there can be additional software control systems for operating the agricultural equipment.

[0082] The aeroponic cultivation device according to the present invention is generally for greenhouse and vertical farming, particularly for commercial greenhouses and vertical farms. In practice, the device may comprise a hollow cultivation bed formed from one or more cultivation bed trays, each cultivation bed / cultivation bed tray having a front end, a back end, a contoured bottom, and an open top. The bottom of the cultivation bed tray may comprise one or more sumps or slopes / tapers depending on the bed width at the bottom of the cultivation bed tray / cultivation bed for collecting / directing nutrient solution to specific locations.

[0083] In general, each ultrasonic transducer may be independently controlled.

[0084] The device may have a standardized interface in the grow bed structure for the introduction of sensors and additional modular devices. The end of the grow bed may be detachable and may be removably secured to another grow bed using a securing attachment. The end of the grow bed may include a T-section for attaching multiple beds together in an adjacent system, and an end section that encloses an interior area and includes an interface for a pipe / tube attachment.

[0085] The device generally includes at least one port, which may be an inlet, an outlet, or both an inlet and an outlet, for the nutrient solution. The solution may be provided from a nutrient solution reservoir via a pipe / tube / conduit, driven by gravity from a relatively low-pressure pump. Other fluid inlets and outlets may be present above the water line for the use of gas and visual sensor devices, as well as for the supply of gases (e.g., air, oxygen, and / or carbon dioxide).

[0086] During use, plant support medium can be placed throughout the grow bed tray / grow bed to support the growing plants and reduce moisture loss. The plant support can be fibrous. The plant support generally supports the crop plants so that the leaves, crown, and fruit are at the top of the plant support and the roots hang below where they may come into contact with the mist generated by the sprayer. This is useful because it allows space for equipment to harvest, monitor, or otherwise care for the crop. An additional benefit of the plant support medium is that it reduces or prevents leakage of aerosols / mist (and moisture) from the root space, as it is important to maintain humidity control within the device, particularly in the root space. Therefore, the device can have rails or other mechanisms that allow for movement or positioning of harvesting, monitoring, or other care devices.

[0087] The apparatus may include a light fixture for suspending a light above the grow bed / grow bed tray and may also include a light attached to the light fixture when in use.

[0088] The device may have an attachment portion for attaching the sprayer to the bottom of the grow bed tray and may include an ultrasonic transducer and an acoustically designed holder for holding the ultrasonic transducer. The ultrasonic transducer typically includes one or more piezoelectric devices. The holder typically is made of an acoustically suitable material (i.e., a material with suitable acoustic properties) and has an appropriate form factor for effectively dispersing the ultrasonically generated mist. The holder and / or ultrasonic transducer may be detachable from the grow bed / grow bed tray and from each other for maintenance.

[0089] Existing sprayers, lights, sensors and other electrically powered devices also have electrical connectors for connecting to a power source.

[0090] The aeroponics device enables a method for vertical hydroponic or aeroponics greenhouse crop production, which method includes connecting the growing beds to a nutrient solution reservoir via tubing and pumps, allowing for the use of both aeroponics and, if desired, hydroponic production.

[0091] Aeroponics involves pumping nutrient solution from a reservoir through tubing into the growing beds so that the trough (i.e., the growing bed tray or trays) has enough nutrient solution to operate fully efficiently and maintain the nutrient solution level at an optimal level for activating the ultrasonic transducers. Through atomization, the trough is typically partially filled. With more nutrient solution, energy dissipates before the aerosol reaches the surface where it is generated. Thus, each transducer may have a focal point where atomization is most effective.

[0092] The ultrasonic transducer operates at a predetermined frequency and power to control droplet size, ensuring the most efficient deposition of nutrient solution onto the plant roots. This depends on the stage of root growth and the density of the root bed. For example, smaller droplets may be used for dense beds and mature plants, while larger droplet sizes may be used for less dense beds and younger plants.

[0093] A less preferred hydroponic method may involve adjusting the height of the plant support within the grow bed tray to reduce the distance between the support and the bottom of the grow bed tray. However, typically, the grow bed tray is filled with nutrient solution, so that the plant roots, if present, are submerged in the nutrient solution. The nutrient solution may be pumped from a reservoir into the grow bed tray / grow bed so that the grow bed is full, thereby maintaining the water level at an optimal level for hydroponic plant growth.

[0094] The device of the present invention is particularly advantageous because it allows users to better control droplet atomization, producing a predictable droplet size distribution with a characteristic aerosol dispersion. The present invention allows for droplet size control using one or more ultrasonic transducers by adjusting and controlling the drive frequency. Furthermore, droplet flow rate (speed) and dispersion (velocity) can be controlled by manipulating the transducer's drive circuitry, which is controlled by the drive voltage / current. Therefore, such control can generally be achieved by having one or more ultrasonic transducers in a holder. The piezoelectric disc characteristics of each transducer are used to select a transducer that generates droplets of the appropriate size and / or speed during operation. The transducers can be positioned so that a predetermined portion of the water column in the grow bed is excited to the point where it atomizes into droplet form. The transducers are mounted in a holder that can conduct vibrations generated within the atomizer through the bottom of the grow bed with minimal energy dissipation. The holder preferably also provides a protective casing, a material for pressurizing the piezoelectric material (especially uniform pressurization), a heat sink, and structural support to hold the transducer in place.

[0095] This device allows for the generation of droplets of nutrient solution of controlled size and behavior through ultrasonic atomization by activating an ultrasonic transducer at a predetermined droplet size.

[0096] The nutrient solution may be prepared using appropriate nutrients dissolved in water, or may be nutrient solution derived from other processes, such as fish farming, especially aquaponics. A combination of aquaponics and aeroponics / hydroponics of the present invention may be advantageous.

[0097] Crops that may be suitable for the apparatus and methods of the present invention include, but are not limited to, salad crops (e.g., baby leaf lettuce, arugula, watercress), herbs (e.g., basil, coriander), scallions, root vegetables (e.g., carrots, radishes, wasabi), fruit crops (e.g., bell peppers, strawberries, tomatoes), and microgreens (e.g., radishes, peas, sunflowers, leeks). [Example]

[0098] (Examples 1 to 8) Several crop plants were experimentally grown for up to 19 days using the inventive aeroponics apparatus shown in FIG.

[0099] The conditions of the test, along with the growth rate and yield results using the aeroponic cultivation device of the present invention, are shown in Table 1. The crops were coriander, fennel, leek, peas (Style variety), radishes (Rioja variety), radishes (Sangria variety), red cabbage, and sunflower.

[0100] [Table 1]

Claims

1. A modular ultrasonically driven grow bed system aeroponic cultivation device for commercial operation, comprising: a growing bed having one or more growing bed trays; each grow bed tray having a bottom and at least two side walls adapted to hold a plant support at a spaced apart position from the bottom of the grow bed tray; 1. An aeroponic cultivation device comprising a plurality of ultrasonic transducers mounted beneath the bottom of the one or more grow bed trays using one or more fasteners for fixing the ultrasonic transducers in place.

2. 2. The aeroponic cultivation apparatus of claim 1, wherein the one or more ultrasonic transducers are held in a holder such that the ultrasonic transducers contact and preferably are pressed against the bottom of the grow bed tray.

3. 3. An aeroponics apparatus according to claim 1 or 2, further comprising one or more atomizer shields for protecting the or each ultrasonic transducer in use.

4. 4. The aeroponic cultivation apparatus according to any one of claims 1 to 3, wherein the or each cultivation bed tray comprises between 2 and 48 ultrasonic transducers, preferably between 4 and 36 ultrasonic transducers, more preferably between 6 and 24 ultrasonic transducers.

5. 5. An aeroponic cultivation device according to any one of claims 1 to 4, wherein each ultrasonic transducer can be independently controlled.

6. 6. An aeroponic cultivation apparatus according to any one of claims 1 to 5, wherein the or each ultrasonic transducer is a piezoelectric transducer.

7. 7. An aeroponic cultivation apparatus according to any one of claims 1 to 6, wherein the or each ultrasonic transducer preferably has a resonant frequency in the kilohertz or megahertz range, more preferably in the range 200 kHz to 100 MHz.

8. 8. The aeroponic cultivation device of claim 1, further comprising at least one liquid port, optionally comprising a liquid inlet for allowing nutrient solution to flow into the bottom of the cultivation bed tray.

9. 9. The aeroponic cultivation device according to claim 1, further comprising one or more sensor fixtures for fixing sensors to the cultivation bed tray, and optionally one or more sensors selected from moisture, light, pH, temperature, carbon dioxide, oxygen, infrared, and ultrasonic sensors fixed to the sensor fixtures.

10. 10. An aeroponic cultivation device according to any one of claims 1 to 9, comprising at least one plant support and a nutrient solution.

11. 10. The aeroponic cultivation apparatus of claim 9, further comprising a plant in the plant support and roots of the plant located in a root space between the plant support and the bottom of the cultivation bed tray during use.

12. 1. A method for crop production comprising: (a) providing an aeroponic cultivation device according to any one of claims 1 to 11; (b) providing a plant support spaced from the bottom of the growing bed tray; (c) providing a crop on the plant support; and Step (c) (i) flowing a nutrient solution into the bottom of the growing bed tray and contacting at least the roots of the plants by immersion; and / or (ii) providing a nutrient solution to the bottom of the growing bed tray, and the nutrient solution is spraying the nutrient solution so that it contacts the roots of the crop; 1. A method for producing crops, comprising:

13. the step of spraying the nutrient solution includes spraying the nutrient solution to provide a controlled droplet size distribution; The method of claim 12 , wherein the droplet size distribution comprises droplets having diameters in the range of 1 to 100 μm.

14. 14. The method of claim 12 or 13, further comprising the steps of providing a root density sensor, sensing the density of the root bed, and spraying the nutrient solution to provide a controlled droplet size distribution corresponding to a predetermined optimal droplet size distribution for the density of the root bed.

15. 15. The method of any one of claims 12 to 14, wherein the nutrient solution comprises aquaculture by-products.

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