Ultra-high density three-dimensional intelligent hydroponic planting system and method for plant factory

Abstract

This invention discloses an ultra-high-density three-dimensional intelligent hydroponic planting system and method for plant factories, belonging to the field of modern facility agriculture equipment technology. The system includes: a multi-layer modular three-dimensional cultivation rack, characterized by at least 12 layers, employing a snap-fit ​​assembly structure, and integrating concealed water and electricity pipelines internally; a gravity flow NFT nutrient solution circulation device, utilizing gravitational potential energy to achieve a layer-by-layer cascading flow of nutrient solution from the top to the bottom, including a top-layer flow stabilizer, inter-layer flow guiding components, and a bottom-layer return system; and a light environment integrated module, embedding LED plant growth light sources inside the crossbeams of the cultivation rack to form an integrated structure for heat dissipation and support. This invention, through its high-density spatial layout (volume ratio of 4.25) and energy-saving gravity flow design, solves the problems of low planting layer count, high energy consumption, and complex piping in traditional plant factories, thereby improving yield per unit area and resource utilization efficiency.

Description

Technical Field

[0001] This invention relates to the field of modern facility agriculture equipment technology, specifically to an ultra-high density three-dimensional intelligent hydroponic planting system and planting method for plant factories. Background Technology

[0002] With the acceleration of global urbanization and the increasing scarcity of arable land, vertical farming, as a highly efficient urban agricultural solution, is receiving widespread attention. Plant factories, an advanced form of vertical farming, achieve year-round continuous crop production through precise intelligent control of growth factors such as light, temperature, water, air, and fertilizer in a closed environment. This has become an important pathway to ensure urban food security and improve resource utilization efficiency. Especially in urban core areas where land resources are extremely scarce, developing modern facility agriculture characterized by "high technology, high quality, and high added value" has become a strategic goal.

[0003] To achieve higher productivity within limited land area, increasing the number of vertical layers in planting racks has become an inevitable trend in the industry. However, when the number of planting layers increases to 10 or more (e.g., 12 layers), traditional plant factory planting racks reveal the following systemic technical challenges in terms of structure, fluid dynamics, light and heat, and automation adaptation: The conflict between light and heat dissipation: Traditional plant factory growing racks often use top-mounted light sources, separating the light source from the growing layer. This not only occupies additional height space, limiting the number of growing layers, but also results in significant heat accumulation in high-layer structures. Heat generated by the upper light source tends to accumulate at the top of the growing rack, leading to a significant temperature difference between the upper and lower layers. The hot air from the upper layer affects the growing environment of the crops in the lower layer, easily inducing physiological diseases such as "heartburn." To solve the heat dissipation problem, traditional solutions often require the addition of ventilation or cooling equipment, further increasing energy consumption and system complexity.

[0004] Nutrient solution circulation suffers from high energy consumption and poor uniformity: Existing technologies generally employ a "parallel supply" mode, where each planting rack has an independent supply branch pipe, with a main pump simultaneously delivering nutrient solution to each rack. In ultra-high structures with 12 or more layers, the piping system becomes extremely complex and difficult to install. Furthermore, to ensure supply pressure at the top layer, the pump head and flow rate requirements increase significantly, leading to a surge in energy consumption. Simultaneously, the parallel mode can cause uneven water pressure between racks due to differences in pipe resistance, resulting in water shortages in some racks and overflows in others, severely impacting crop growth uniformity. In addition, the dissolved oxygen content of the nutrient solution gradually decreases during circulation, necessitating additional aeration equipment, further increasing system investment and operating costs.

[0005] Balancing structural stability and installation efficiency is challenging: High-rise cultivation racks demand high structural load-bearing capacity and stability. While traditional welded racks offer structural stability, they suffer from long installation cycles, poor flexibility, and difficulty adapting to the varying height requirements of different crops. Furthermore, subsequent modifications or relocations are costly and difficult. How to achieve a modular, adjustable, and easy-to-install structural design while ensuring the stability of racks exceeding 12 stories has become a pressing technical challenge for the industry.

[0006] Fourth, exposed pipelines affect the cleanliness of the environment and automated operations. In existing planting systems, the supply and return pipelines, as well as electrical wiring, are mostly exposed outside the cultivation racks. This not only leads to dust accumulation, making cleaning difficult and increasing the risk of pests and diseases, but also occupies space between layers, severely hindering the free movement of automated logistics equipment (such as shuttles and robotic arms). This makes it difficult for existing ultra-high-rise planting systems to achieve fully automated operations from planting to harvesting, still requiring a significant amount of manual labor, which contradicts the goal of highly intelligent plant factories.

[0007] Fifth, there is a lack of systematic integrated design for ultra-high-density scenarios. While existing technologies include modular planting systems such as Sananbio's RADIX, these are primarily geared towards low- to mid-level applications, lacking comprehensive fluid dynamics optimization and integrated photothermal design for ultra-high-density scenarios of 12 layers or more. The various subsystems (structure, circulation, lighting, and environmental control) are often designed independently and simply superimposed, failing to create synergy and making it difficult to simultaneously resolve the aforementioned multiple technical contradictions. Consequently, the overall performance of ultra-high-rise planting systems falls far short of theoretical expectations.

[0008] In summary, there is an urgent need to develop a three-dimensional intelligent hydroponic planting system and method that can support ultra-high-density planting of 12 layers or more, and has low-energy gravity flow irrigation, integrated light and heat, concealed pipeline layout, and fully automated logistics docking capabilities, in order to break through existing technological bottlenecks and promote the development of plant factories towards a higher level and higher efficiency. Summary of the Invention

[0009] The purpose of this invention is to provide an ultra-high density three-dimensional intelligent hydroponic planting system and planting method for plant factories. Through the system integration of four major technical pillars, namely "gravity flow cascade irrigation, embedded photothermal integration, hidden pipeline layout, and distributed environmental control", an intelligent hydroponic equipment system suitable for ultra-high density planting of more than 12 layers is constructed.

[0010] To achieve the above objectives, the present invention adopts the following technical solution: A high-density, three-dimensional intelligent hydroponic planting system includes: The three-dimensional cultivation rack module is assembled from several columns and beams using snap-fit ​​connectors. Vertically, it is divided into at least 12 planting levels, forming an ultra-high-density planting structure with a height of 6 to 10 meters. The height of each planting level is adjustable, ranging from 200mm to 600mm, to accommodate the different growth heights of various crops. The columns have internal hollow cavities to conceal nutrient supply pipes and electrical wiring, creating unobstructed passageways between the cultivation rack levels for automated logistics equipment. To further enhance the overall stability of the ultra-high structure with more than 12 levels, diagonal tie rods are also installed between the columns.

[0011] The planting trough assembly, located on each planting level, supports the planting board and crops. The planting trough is made of food-grade polypropylene material, with reinforcing ribs at the bottom. These ribs are arranged in a herringbone pattern, branching out from the center of the inlet end and converging towards the center of the outlet end, forming a continuous flow path. This guides the nutrient solution to spread evenly within the wide trough, preventing short-circuiting and ensuring a liquid film coverage rate of over 98%.

[0012] The gravity-flow nutrient solution circulation subsystem includes a supply pump, a top-level distributor, interlayer overflow guides, and a return tank. The supply pump delivers the nutrient solution to the top layer of the three-dimensional cultivation module. Under gravity, the nutrient solution flows through the top planting trough in an NFT (Natural Factor Transfer) mode and then cascades down to the next planting trough via the interlayer overflow guides, forming a cascaded circulation path requiring only one lift, until it flows out from the bottom layer. The interlayer overflow guides include overflow outlets at the bottom of the planting troughs and noise-reducing guide pipes with spiral guide grooves on their inner walls. These guide the water flow to rotate and fall along the wall, simultaneously increasing the contact area between the nutrient solution and air to improve dissolved oxygen content and reducing water flow noise. An online detection and control unit is installed between the supply pump and the return tank to monitor the EC and pH values ​​of the returned nutrient solution in real time and automatically control the replenishment of concentrated and acid / alkaline solutions, forming a closed-loop nutrient solution composition maintenance system.

[0013] The integrated lighting environment subsystem includes LED plant growth light strips embedded in the crossbeams above each planting trough. Thermally conductive silicone grease is applied between the heat dissipation substrate of the light strip and the crossbeams, providing thermal conductivity. The overall metal structure of the three-dimensional cultivation rack module serves as an auxiliary heat sink. The LED plant growth light strips employ a variable spectrum design, including red (660nm), blue (450nm), and far-red (730nm) LED chips. The surface of the LED chips is covered with a nano-waterproof coating, achieving an IP65 protection rating.

[0014] A distributed environmental monitoring sensor array is integrated into the side wall of the uprights of each cultivation rack, corresponding one-to-one with the planting level. It is used to monitor the temperature, humidity, CO2 concentration and light intensity of the level in real time, and transmit the data to the central control system to realize independent environmental regulation of each level.

[0015] The aforementioned subsystems form a collaborative structure: the gravity flow nutrient solution circulation subsystem reduces the number of supply pipelines through a cascaded supply system with only one lift, providing a structural basis for concealing the supply pipelines and electrical wiring inside the columns; the concealed supply pipelines and electrical wiring create unobstructed passageways between cultivation rack layers, providing a spatial basis for the passage of automated logistics equipment in the 12-layer ultra-high-density architecture; the embedded LED plant growth light strips do not occupy additional layer height, allowing the planting layer height to be compressed to 200mm, supporting an ultra-high-density configuration of at least 12 layers.

[0016] This invention also provides a method for ultra-high density three-dimensional intelligent hydroponic cultivation using the above-mentioned system, comprising the following steps: Frame construction steps: Construct a three-dimensional cultivation frame module divided into at least 12 planting levels vertically. Conceal the hydration pipes and electrical wiring inside the columns, creating unobstructed passageways between the cultivation frame levels. Columns and beams are assembled without welding using snap-fit ​​connectors. The height of each planting level can be adjusted from 200mm to 600mm according to the crop variety.

[0017] Planting steps: The cultivated seedlings, along with the planting boards, are transported via an automated logistics system through the barrier-free passageway into the designated planting troughs. The automated logistics system includes a shuttle car and a conveyor line. The shuttle car travels along the passageway between the cultivation racks, and a robotic arm delivers the planting boards into the planting troughs.

[0018] Nutrient solution circulation steps: Initiate gravity-flow nutrient solution circulation, controlling the supply pump to lift the nutrient solution to the top layer in one go. Under gravity, the nutrient solution flows through the top planting trough in an NFT (Nutrient Flow Forward) mode, then falls layer by layer to the next planting trough through a silent guide pipe with spiral guide channels on the inner wall. The nutrient solution rotates and falls along the spiral guide channels, simultaneously achieving oxygenation and noise reduction during the descent, increasing the dissolved oxygen content to above 8.2 mg / L and reducing water flow noise to below 45 dB. By controlling the variable frequency operation of the supply pump, a differentiated supply mode is implemented: continuous supply during the light period to ensure the crop's photosynthetic needs for water and nutrients; and intermittent supply during the dark period, with an interval of 15 minutes of supply followed by 45 minutes of cessation, to promote root respiration and prevent root zone hypoxia.

[0019] Light control steps: Based on the crop growth model, the spectral ratio and illumination period of each layer of LED plant growth light strips are adjusted in stages. The LED plant growth light strips are embedded in the crossbeams above the planting trough, and their heat dissipation substrates are thermally connected to the crossbeams, utilizing the overall metal structure of the cultivation rack for auxiliary heat dissipation. Specifically, differentiated spectral control is performed according to the crop growth stage: Early stage regulation after transplanting: On the 1st to 3rd day after crop transplanting, set the proportion of blue light to 30%-40%, red light to 50%-60%, and far-red light to 5%-15% to inhibit excessive growth and promote thick stems and root development. Rapid growth period regulation: 4-20 days after crop transplanting, set the proportion of red light to 70%-80%, blue light to 15%-25%, and far-red light to 3%-8% to promote leaf expansion and biomass accumulation. Pre-harvest regulation: 3-5 days before harvest, increase far-red light irradiation, setting the proportion of far-red light to 15%-25%, red light to 60%-70%, and blue light to 10%-20%, in order to regulate leaf morphology, improve leaf color, and reduce nitrate content.

[0020] Environmental feedback control steps: The temperature, humidity, CO2 concentration and light intensity of each level are monitored in real time through a distributed sensor array. The central control system receives the monitoring data and compares it with the preset threshold. When any environmental parameter exceeds the set threshold, the corresponding environmental control equipment or LED light source is automatically adjusted to keep the fluctuation range of microenvironmental parameters at each level within ±5% of the set value.

[0021] Nutrient solution online control steps: The EC value and pH value of the reflux nutrient solution are monitored in real time by an online detection and control unit located between the supply pump and the return tank. When the EC value or pH value deviates from the set threshold, the replenishment of concentrate or acid / alkali solution is automatically controlled to maintain the stability of the nutrient solution composition.

[0022] Harvesting steps: After the crops mature, the entire tray of crops is removed using automated logistics equipment.

[0023] The above methods can be used to optimize parameters for different crops. For example, for leafy vegetables, the light intensity can be increased to 200-250 µmol / m² / s during the rapid growth period, and the photoperiod can be set to 18 hours of light and 6 hours of dark to shorten the growth cycle. For perilla, UV-A band (365nm) irradiation can be added during the rapid growth period, with 1-3 hours of irradiation per day to promote the synthesis of anthocyanins and volatile oils and enhance medicinal value. For strawberry seedlings, the layer height can be adjusted to 350-450mm, the ratio of red light to blue light can be set to 6:4, and a continuous liquid supply mode can be adopted to achieve high-density propagation of runner seedlings.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a modular, three-dimensional cultivation rack with at least 12 layers, combined with an adjustable layer height design (200-600mm), achieving an effective planting area several times greater than traditional planting systems per unit area. Practical verification has shown that the plot ratio can reach over 4.25, and the yield per unit area is 8-10 times higher than traditional greenhouse cultivation. It is particularly suitable for high-land-value scenarios such as urban core areas, providing a highly efficient solution for urban agriculture.

[0025] The gravity-flow cascaded NFT irrigation system only requires lifting the nutrient solution to the top layer once, allowing it to fall layer by layer under gravity. This avoids pressurizing the intermediate layers, reducing pump energy consumption by approximately 55%-60% compared to traditional parallel supply systems. Simultaneously, the natural aeration effect of the spiral guide channel during the interlayer cascading process raises the dissolved oxygen content of the nutrient solution to 8.2-8.8 mg / L, approaching saturation, eliminating the need for additional aeration equipment and further reducing system operating energy consumption.

[0026] LED plant growth light strips are embedded inside the crossbeams, and the heat dissipation substrate of the light strips is thermally connected to the metal structure of the cultivation rack. The entire rack frame serves as an auxiliary heat sink, achieving passive cooling without the need for an additional fan. Actual testing showed that under full load operation at 12 layers, the junction temperature of the light strips was reduced by approximately 12°C compared to traditional external light sources, and the lifespan of the LEDs is expected to be extended by more than 8000 hours. This effectively solves the problem of heat accumulation in ultra-high-density planting, avoids the adverse effects of hot air from the upper layers on the crops below, and prevents physiological diseases such as "heartburn" from occurring.

[0027] By integrating the liquid supply pipeline, return pipeline, and electrical cables into the hollow cavity of the column, a "hidden" layout is achieved, avoiding exposed pipelines and dust accumulation, and reducing the risk of pests and diseases. More importantly, the hidden design creates unobstructed passageways between the cultivation racks, providing smooth space for the operation of automated logistics equipment (such as shuttle cars and conveyor lines). This enables fully automated operations from planting to harvesting, significantly improving production efficiency and reducing labor costs.

[0028] By combining a distributed sensor array with a variable-spectrum LED light source, independent monitoring and control of the microenvironment at each level are achieved. Through phased dynamic adjustment of light quality, intensity, and photoperiod, coupled with differentiated control of the nutrient solution circulation strategy, refined management throughout the entire growth cycle from planting to harvest is realized. Actual planting data shows that the crop growth cycle is shortened by 5-7 days compared to the traditional NFT system; the nitrate content in the leaves at harvest is lower than the national standard for pollution-free vegetables; and the vitamin C content is increased by approximately 18% compared to traditional planting methods, effectively improving crop yield and nutritional quality.

[0029] Utilizing a snap-fit ​​assembly structure, no welding is required, increasing installation efficiency by approximately 70% compared to traditional welded shelving. High-strength aluminum alloy profiles and diagonal tie rods ensure the structural stability and corrosion resistance of ultra-high-rise shelving units with 12 or more layers. Furthermore, the layer height can be flexibly adjusted according to crop requirements, meeting diverse planting needs and facilitating future modifications and relocation.

[0030] The three-dimensional cultivation rack module, gravity-flow nutrient solution circulation subsystem, and light environment integration subsystem of this invention form a synergistic structure: gravity-flow irrigation reduces the number of supply pipes, creating conditions for concealed pipe layout; concealed pipe layout frees up interlayer space, providing channels for automated logistics; embedded light sources do not occupy layer height, supporting ultra-high density configuration; spiral flow guides simultaneously achieve oxygenation and noise reduction, simplifying system composition. It is not only suitable for hydroponic cultivation of leafy vegetables, but can also be extended to the seedling and dwarfing cultivation of medicinal plants (such as perilla, which can increase rosmarinic acid content by about 35% and total volatile oil content by about 28%), spice plants, and some fruit and vegetable crops (such as strawberry seedling cultivation, increasing the number of seedlings per unit area by more than 12 times compared to traditional planar seedling cultivation), showing promising industrial application prospects. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the ultra-high density three-dimensional intelligent hydroponic planting system of the present invention; Figure 2 This is a schematic diagram of the overall structure of the three-dimensional cultivation rack module 1 and the planting trough assembly 2 in this invention (12-layer view).

[0032] Figure 3 This is a schematic diagram of the gravity flow nutrient solution circulation subsystem 3 in this invention.

[0033] Figure 4 This is a partial cross-sectional view of the interlayer overflow guide in this invention.

[0034] In the picture: 1-Three-dimensional cultivation rack module, 11-Upright column, 12-Horizontal beam; 2-Planting trough assembly; 3-Gravity flow nutrient solution circulation subsystem, 31-Storage tank, 32-Supply pump, 33-Top layer distributor, 34-Interlayer overflow guide, 341-Overflow port, 342-Silence guide pipe, 343-Spiral guide groove, 35-Return tank; 4-Light Environment Integration Subsystem; 5-Environmental monitoring sensor array. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the scope of protection of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0036] "NFT" refers to Nutrient Film Technique, which involves the nutrient solution flowing in a thin layer across the bottom of the planting trough, allowing the crop roots to be partially submerged in the nutrient solution and partially exposed to the air, thus balancing water and nutrient absorption with root respiration. "Gravity Flow Cascade" refers to the nutrient solution being lifted to the top layer only once, and then flowing sequentially through each planting trough layer under gravity, forming a continuous flow path from top to bottom. "Ultra-High Density" refers to having at least 12 planting levels vertically, with a total height of 6 to 10 meters, resulting in a significantly larger effective planting area than traditional plant factory planting racks.

[0037] Example: This embodiment provides an ultra-high density three-dimensional intelligent hydroponic planting system, such as Figure 1 As shown, the system mainly includes a three-dimensional cultivation rack module 1, a planting trough assembly 2, a gravity flow nutrient solution circulation subsystem 3, and a light environment integrated subsystem 4.

[0038] like Figure 2 As shown, the three-dimensional cultivation rack module 1 is assembled from several high-strength aluminum alloy columns 11 and crossbeams 12 using snap-fit ​​connectors. The columns 11 are made of hollow square cross-section profiles with internal hollow cavities for concealing the liquid supply pipes and electrical wiring. The crossbeams 12 are arranged in layers along the vertical direction, with adjacent crossbeams forming a planting level. In this embodiment, the three-dimensional cultivation rack module 1 is divided into 12 planting levels vertically, with a total height of 8.5 meters. The height of each planting level can be adjusted according to the crop variety and growth stage, ranging from 200mm to 600mm. Specifically, for dwarf leafy vegetables such as Shanghai bok choy, the level is set at 300mm; for medium-height basil, the level is set at 450mm; and for taller perilla, the level is set at 550mm. By adjusting the installation position of the connectors, the fixed height of the crossbeams 12 on the columns 11 can be flexibly changed, achieving level height adjustment. A 20cm space is provided for lighting and ventilation. This compact design results in a volumetric ratio of 4.25 for the cultivation workshop, meaning that the effective planting area per unit area is dozens of times that of open-field cultivation. The planting trough assembly 2 is disposed on each of the planting levels and includes a planting trough 21 and a planting plate 22. The planting trough 21 is integrally injection molded from food-grade polypropylene (PP) material, and its bottom is provided with flow-guiding reinforcing ribs. The flow-guiding reinforcing ribs are distributed in a herringbone pattern, extending from the liquid inlet end of the planting trough 21 to both sides and then converging at the liquid outlet end, to guide the nutrient solution to spread evenly in the wide trough body and prevent short-circuiting of the liquid flow. The planting plate 22 is covered on the upper part of the planting trough 21, and the planting plate has planting holes for fixing the crop plants.

[0039] The gravity-flow nutrient solution circulation subsystem 3 includes a storage tank 31, a supply pump 32, a top-layer distributor 33, an interlayer overflow guide 34, and a return tank 35, such as... Figure 3 As shown.

[0040] The liquid storage tank 31 is located on one side of the bottom of the cultivation rack, with a total capacity of 3 tons. It adopts a recessed horizontal water tank structure to lower the system's center of gravity. The liquid supply pump 32 is a constant pressure variable frequency water pump, with its inlet connected to the liquid storage tank 31 and its outlet connected to the top layer of the three-dimensional cultivation rack module 1 via a main water supply pipeline. The main water supply pipeline is laid upwards along the hollow cavity of the column 11, thus concealing the pipeline. By integrating the pipeline inside the column, not only is the overall aesthetic improved, but more importantly, it avoids interference with the operation of automated logistics equipment caused by exposed pipelines, while also reducing dust accumulation dead spots and lowering the risk of pest and disease breeding.

[0041] At the inlet end of the top planting layer, a top-level nutrient solution distributor 33 is provided. This top-level nutrient solution distributor 33 is a steady-flow nutrient solution distribution structure, including an inlet, a steady-flow chamber, and an outlet weir. The nutrient solution supply pump 32 delivers the nutrient solution to the top-level nutrient solution distributor 33. After entering the steady-flow chamber 33, the flow rate of the nutrient solution decreases and the pressure becomes uniform. Then, it flows over the outlet weir 33 and spreads evenly on the bottom surface of the top planting trough 21 in the form of a film flow. The setting of the steady-flow chamber ensures that the flow rate of the nutrient solution entering the planting trough is stable, avoiding the liquid flow impact caused by the start-up and shutdown of the nutrient solution supply pump or frequency fluctuations, thereby ensuring the stability of the nutrient solution film thickness in the crop root zone.

[0042] The nutrient solution flows under gravity in an NFT (Nutrient Flow Therapy) mode through the top planting trough 21, passes through the crop root system, and collects at the bottom of the end of planting trough 21. The interlayer overflow guide is located between the end of each planting trough and the inlet end of the next planting trough. Figure 4As shown, specifically, the interlayer overflow guide 34 includes an overflow port 341 and a silencer guide pipe 342. The overflow port 341 is located at the bottom end of the planting trough 21. The upper end of the silencer guide pipe 342 is sealed to the overflow port, and the lower end extends above the liquid inlet of the next planting trough. The inner wall of the silencer guide pipe 342 is provided with a spiral guide groove 343 to guide the water flow to rotate and fall along the wall. When the nutrient solution falls from the upper layer to the lower layer, it rotates and flows along the spiral guide groove 343. On the one hand, the centrifugal force causes the water flow to adhere to the pipe wall, effectively reducing the noise of the falling water (the measured noise value is less than 45dB); on the other hand, the liquid comes into full contact with the air during the rotation, increasing the gas-liquid contact area and raising the dissolved oxygen content of the nutrient solution to above 8.5mg / L, close to saturation. Compared to the "whooshing" sound of water flowing freely due to the free fall in traditional layered liquid supply systems, this design reduces the noise level in the plant factory to that of a regular office, significantly improving the working environment.

[0043] The nutrient solution flows sequentially through the 12th layer, the 11th layer, and so on down to the 1st layer. The nutrient solution flowing out of the bottom planting trough flows into the return tank 350 through the return pipe. The return tank 350 is connected to the storage tank 310, forming a closed loop.

[0044] An online monitoring and control unit 36 ​​is installed between the supply pump 32 and the return tank 35. This unit includes an EC sensor, a pH sensor, and an automatic replenishment device. The EC and pH sensors monitor the conductivity and pH of the returned nutrient solution in real time and transmit the data to the central control system. When the EC or pH value deviates from a set threshold, the central control system activates the automatic replenishment device to replenish concentrated nutrient solution or pH-adjusting solution, maintaining the stability of the nutrient solution composition. Through online control, the system can operate continuously for months without manual intervention in nutrient solution preparation, significantly reducing maintenance costs.

[0045] Regarding the nutrient solution circulation control strategy, a differentiated nutrient solution supply mode is achieved by controlling the variable frequency operation of the nutrient solution supply pump 32: during the light period (e.g., 6:00-20:00 daily), continuous nutrient solution supply is maintained to ensure the crop's water and nutrient requirements for photosynthesis; during the dark period (20:00-6:00 the next day), an intermittent nutrient solution supply mode is adopted, with an interval of 15 minutes of supply followed by 45 minutes of cessation, to promote root respiration and prevent root hypoxia. This nutrient solution supply strategy, dynamically regulated according to the crop's physiological rhythm, can further save approximately 15% of energy compared to the traditional constant nutrient solution supply mode, while significantly improving root vitality.

[0046] The integrated lighting environment subsystem 4 includes LED plant growth light strips, which are embedded in the crossbeams 12 above each planting trough 21. Specifically, the lower surface of the crossbeam 12 has a mounting groove extending along its length. The LED plant growth light strips are inserted into the mounting grooves, and the heat dissipation substrate of the light strips is tightly attached to the bottom surface of the mounting grooves of the crossbeams, with thermally conductive silicone grease applied between them. Since the crossbeams 12 and the columns 11 are both made of metal (aluminum alloy), and the entire three-dimensional cultivation rack module 1 constitutes a large metal skeleton structure, the heat generated by the light strips during operation is conducted to the crossbeams through the heat dissipation substrate, and then radiated to the surroundings through the crossbeams 12 and the columns 11, achieving passive heat dissipation without the need for additional fans, effectively solving the problem of heat accumulation under ultra-high density planting. Actual testing shows that under an ambient temperature of 25℃ and full-load operation of 12 layers, the junction temperature of the light strips is reduced by approximately 12℃ compared to traditional external light sources, and the lifespan of the LEDs is expected to be extended by more than 8000 hours.

[0047] The LED plant growth light strip features a variable spectrum design, with its LED chips comprising a red light chip (peak wavelength 660nm), a blue light chip (peak wavelength 450nm), and a far-red light chip (peak wavelength 730nm). These three types of chips are independently controlled, and the spectrum can be dynamically adjusted by regulating the driving current ratio of each chip. The surface of the LED chips is covered with a nano-waterproof coating, achieving an IP65 protection rating, allowing it to withstand the high humidity environment (relative humidity above 85%) within plant factories.

[0048] In terms of spectral regulation strategy, based on crop growth models, the spectral ratio and illumination period of each layer of LED light source are adjusted in stages. Taking Shanghai Green (Dwarf Green) as an example: In the early stage after transplanting (days 1-3): set the light intensity to 35% blue light, 55% red light, and 10% far-red light, with a light intensity of 120 µmol / m² / s and a photoperiod of 16h / 8h. A higher proportion of blue light helps to inhibit seedling etiolation and promotes robust stems and root development.

[0049] Rapid growth period (days 4-20): The light intensity was set at 75% red light, 20% blue light, and 5% far-red light, with the light intensity increased to 220 µmol / m² / s and the photoperiod at 18h / 6h. The high proportion of red light promoted leaf expansion and biomass accumulation, significantly increasing yield.

[0050] Three days before harvest: Increase far-red light irradiation, setting the proportion of red light to 65%, blue light to 15%, and far-red light to 20%, maintaining a light intensity of 200 µmol / m² / s, and adjusting the light cycle to continuous illumination (24h). Far-red light treatment can promote leaf extension, improve leaf color, and effectively reduce leaf nitrate content (measured reduction of 25%-30%).

[0051] The above spectral ratios and light intensity parameters can be customized according to crop varieties. For example, for perilla, increasing UV-A band (peak wavelength 365nm) irradiation during the rapid growth period can promote the synthesis of anthocyanins and volatile oils, thereby enhancing the flavor and nutritional value of the product.

[0052] like Figure 1 As shown, the system also includes a distributed environmental monitoring sensor array 5. This sensor array is integrated into the side wall of the columns 11 of each cultivation rack, corresponding one-to-one with the planting level. Each environmental monitoring sensor array 5 includes a temperature sensor, a humidity sensor, a CO2 concentration sensor, and a light intensity sensor. Each sensor is embedded in a mounting hole in the side wall of the column 11, with the sensor probe facing the planting trough 21, for real-time monitoring of the microenvironmental parameters near the crop canopy at that level.

[0053] All sensors are connected to the central control system 6 via signal cables hidden within the hollow cavity of column 11. The central control system 600 includes an industrial control computer, a touchscreen user interface, and a data storage unit. The central control system receives real-time data collected by each sensor and, in conjunction with a preset crop growth model, automatically coordinates the control of the liquid supply pump, LED plant growth light strips 410, and environmental control equipment (such as air conditioners, dehumidifiers, and CO2 supply systems). For example, when the temperature of a certain level exceeds a set threshold, the system can automatically adjust the driving current of the LED light strips above that level to reduce heat generation, while simultaneously coordinating with the air conditioning system to cool down; when the CO2 concentration is lower than a set value, the CO2 supply valve is automatically opened to replenish CO2 to a level of 800-1000 ppm.

[0054] The distributed sensing architecture of this invention, combined with concealed wiring, enables independent control of the microenvironment at each level. Compared to traditional plant factories that centrally place sensors in the operating channels, this solution can accurately sense the actual environmental state of each level, avoiding control deviations caused by uneven airflow organization.

[0055] This embodiment provides a planting method using the above system, including the following steps: Step S1: Construct a three-dimensional cultivation structure with at least 12 layers and configure light, liquid, and gas systems. Specifically, following the methods described in Examples 1 to 4, construct a three-dimensional cultivation rack module 100, install a gravity flow nutrient solution circulation subsystem 300, a light environment integrated subsystem 400, and an environmental monitoring sensor array 500, and perform system integration testing to ensure that each subsystem operates normally.

[0056] Step S2: The cultivated seedlings, along with the planting boards, are transported to the designated planting troughs using automated logistics equipment. This automated logistics equipment includes a shuttle and a conveyor line. The shuttle travels along the channels between the cultivation racks, transporting the planting boards carrying the seedlings from the seedling area to the cultivation area, and then a robotic arm places the planting boards one by one onto the planting troughs at each level. Because this invention conceals all pipelines and wiring inside the columns, there are no exposed obstacles between the cultivation rack levels, providing a smooth passage for the shuttle.

[0057] Step S3: Initiate gravity-flow nutrient solution circulation, controlling the supply pump to lift the nutrient solution to the top layer, utilizing gravity to achieve full-level irrigation. During the initial supply phase, the supply pump starts slowly using a variable frequency drive to avoid water flow impact. Once a stable film flow is formed in the top layer distributor, the supply pump switches to constant pressure operation mode. The nutrient solution falls layer by layer through all planting levels before returning to the storage tank, completing the circulation. Continuous supply is maintained during the light period, while an intermittent supply mode is used during the dark period, with an interval of 15 minutes of supply followed by 45 minutes of cessation.

[0058] Step S4: Based on the crop growth model, adjust the spectral ratio and illumination cycle of each layer of LED light sources in stages. The central control system automatically outputs spectral control commands according to the preset crop growth model (including three stages: early planting, rapid growth, and pre-harvest) to adjust the driving current ratio of each chip in the LED plant growth light strip. At the same time, based on the real-time light intensity feedback from the sensors in each layer, closed-loop adjustment is performed to ensure that the light intensity is consistent with the set value.

[0059] Step S5: During the planting process, the central control system continuously monitors the temperature, humidity, CO2 concentration, and nutrient solution EC and pH value at each level, compares them with the set thresholds, and automatically starts and stops the corresponding environmental control equipment and nutrient solution adjustment equipment to maintain a stable growth environment.

[0060] Step S6: After the crops mature, the entire tray of crops is removed using automated logistics equipment. During harvesting, a shuttle vehicle travels to the corresponding cultivation rack, and a robotic arm removes the planting tray along with the mature crops from the planting trough and transports it to the harvesting and packaging area. Empty planting trays are cleaned and disinfected before being returned to the seedling area for the next round of planting.

[0061] Example of effect: In a plant factory project in Pudong New Area, Shanghai, a building with an area of ​​4,500 square meters was constructed. 2 The building is a single structure equipped with the ultra-high density three-dimensional intelligent hydroponic planting system of this invention. The system has a total of 120 sets of three-dimensional cultivation rack modules, each with 12 layers, for a total of 1440 planting layers, and the effective planting area is equivalent to 15 times that of traditional flat planting.

[0062] The data from six consecutive planting trials of dwarf Shanghai bok choy are as follows: Average yield per crop: 2.8 kg / m² (based on land area), annual yield is about 16.8 kg / m² / year, which is 8-10 times that of traditional greenhouse cultivation; Energy consumption of the nutrient solution circulation system pump: Compared with the traditional parallel nutrient supply system, it saves 58.7% energy; Interlayer flow rate deviation: The flow rate deviation between the inlet and outlet of each layer of the planting trough is ≤4.2%, and the interlayer flow rate deviation is ≤5.0%; Dissolved oxygen content in nutrient solution: After interlayer drop aeration, the dissolved oxygen content is stable at 8.2-8.8 mg / L, requiring no additional aeration equipment; Growth cycle: The average growth cycle of Dwarf Green from planting to harvest is 28 days, which is 5-7 days shorter than the traditional NFT system; Crop quality: At harvest, the average nitrate content of the leaves was 1850 mg / kg (FW), which is lower than the national standard for pollution-free vegetables (≤3000 mg / kg), and the vitamin C content was about 18% higher than that of traditional cultivation. System stability: After 6 months of continuous operation, the fluctuation range of environmental parameters at each level was controlled within ±5% of the set value, and no physiological diseases such as "heartburn" occurred.

[0063] Comparative experiment: To further verify the technical effects of this invention, a control group was set up in the same plant factory. The control group used a traditional 6-layer planting rack, a parallel nutrient solution supply system, and an external LED light source; other environmental conditions (temperature, CO2 concentration, nutrient solution formula) were kept consistent with the experimental group. The comparison results showed: The yield per unit area of ​​the experimental group was 2.3 times that of the control group; The energy consumption per unit yield (calculated as electricity consumption per kilogram of fresh weight) in the experimental group was 42% lower than that in the control group; The growth uniformity (measured by the coefficient of variation of plant height) among the layers in the experimental group was 6.8%, while that in the control group was 15.3%. No "heartburn" disease was observed in the experimental group during the high-temperature period in summer (ambient temperature 32℃), while the incidence of heartburn disease in the control group above the 4th layer reached 12.5%.

[0064] The above comparative data fully demonstrates that the systematic design scheme of the present invention has significant technical advantages in ultra-high density planting scenarios.

[0065] The above-described embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, such as adjusting the number of planting layers, changing the layer height adjustment range, optimizing the spectral ratio, and adding additional environmental control equipment. These modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A high-density, three-dimensional intelligent hydroponic planting system for plant factories, characterized in that, include: The three-dimensional cultivation rack module is assembled from several columns and beams through connectors. The three-dimensional cultivation rack module is divided into at least 12 planting levels in the vertical direction, forming an ultra-high density planting structure with a height of 6 to 10 meters. The planting trough assembly consists of planting troughs disposed on each of the planting levels for supporting the planting board and crops; The gravity flow nutrient solution circulation subsystem includes a supply pump, a top-level distributor, an interlayer overflow guide, and a return tank. The supply pump delivers the nutrient solution to the top layer of the three-dimensional cultivation rack module. Under the action of gravity, the nutrient solution flows through the top-level planting trough in an NFT mode and falls layer by layer to the next planting trough through the interlayer overflow guide until it flows out from the bottom layer. The integrated lighting environment subsystem includes LED plant growth light strips embedded in the crossbeams above each layer of planting troughs. The heat dissipation substrate of the light strips is thermally connected to the crossbeams, and the overall metal structure of the three-dimensional cultivation rack module is used as an auxiliary heat dissipation body. The column has a hollow cavity inside, which is used to hide the liquid supply pipeline and electrical wiring, so that the layers of the cultivation rack can form an unobstructed passage for automated logistics equipment.

2. The ultra-high density three-dimensional intelligent hydroponic planting system according to claim 1, characterized in that, The interlayer overflow guide includes: An overflow outlet is located at the bottom end of the planting trough; A silencer guide pipe is connected between the overflow port of the upper planting trough and the liquid inlet of the lower planting trough. The inner wall of the silencer guide pipe is provided with a spiral guide groove to guide the water flow to rotate and fall along the wall. At the same time, it can achieve the dual functions of increasing the contact area between the nutrient solution and the air to improve the dissolved oxygen content and reducing the noise of the water flow.

3. The ultra-high density three-dimensional intelligent hydroponic planting system according to claim 1, characterized in that, The height of each plant-grade layer in the three-dimensional cultivation rack module is adjustable, ranging from 200mm to 600mm, to accommodate the different growth height requirements of crops.

4. The ultra-high density three-dimensional intelligent hydroponic planting system according to claim 1, characterized in that, The connector is a snap-fit ​​connector, which enables weld-free assembly of the columns and beams and flexible adjustment of the floor height.

5. The ultra-high density three-dimensional intelligent hydroponic planting system according to claim 1, characterized in that, The light strip adopts a variable spectrum design, including a 660nm red light chip, a 450nm blue light chip and a 730nm far-red light chip; thermally conductive silicone grease is coated between the heat dissipation substrate and the crossbeam of the light strip, and the surface of the light beads is covered with a nano-waterproof coating.

6. The ultra-high density three-dimensional intelligent hydroponic planting system according to claim 1, characterized in that, It also includes a distributed environmental monitoring sensor array, which is integrated into the side wall of the column of each cultivation rack and corresponds one-to-one with the planting level. It is used to monitor the temperature, humidity, CO2 concentration and light intensity of the level in real time and transmit the data to the central control system to realize independent environmental control of each level.

7. The ultra-high density three-dimensional intelligent hydroponic planting system according to claim 1, characterized in that, The planting trough assembly is made of food-grade polypropylene material. The bottom of the trough is equipped with flow-guiding reinforcing ribs. The reinforcing ribs are distributed in a herringbone shape, branching out from the center of the liquid inlet end to both sides and converging towards the center of the liquid outlet end to form a continuous flow-guiding path. This is used to guide the nutrient solution to spread evenly in the wide trough body, prevent short-circuiting of the liquid flow, and ensure that the liquid film coverage rate reaches more than 98%.

8. The ultra-high density three-dimensional intelligent hydroponic planting system according to claim 1, characterized in that, An online detection and control unit is provided between the supply pump and the return tank to monitor the EC value and pH value of the refluxed nutrient solution in real time, and automatically control the replenishment of concentrate and acid / alkali solution to form a closed-loop nutrient solution component maintenance system.

9. A planting method implemented using the system as described in any one of claims 1-8, characterized in that, Includes the following steps: Frame construction steps: Construct a three-dimensional cultivation rack module that is divided into at least 12 planting levels in the vertical direction, and hide the liquid supply pipeline and electrical wiring inside the columns to create unobstructed passages between the cultivation rack layers; Planting steps: The cultivated seedlings, along with the planting board, are transported through the barrier-free channel into the designated planting trough via automated logistics equipment; Nutrient solution circulation steps: Start the gravity flow nutrient solution circulation, control the supply pump to lift the nutrient solution to the top layer at once, so that the nutrient solution flows through the top planting trough in NFT mode under the action of gravity, and then falls to the next planting trough layer by layer through the interlayer overflow guide, until it flows through all planting levels and then flows back, forming a cascaded circulation. Light control steps: According to the crop growth model, the spectral ratio and light cycle of each layer of LED plant growth light strips are adjusted in stages. The LED plant growth light strips are embedded in the crossbeams installed above the planting trough. Their heat dissipation substrates are thermally connected to the crossbeams, and the overall metal structure of the cultivation rack is used for auxiliary heat dissipation. Harvesting steps: After the crops mature, the entire tray of crops is removed using automated logistics equipment.

10. The planting method according to claim 9, characterized in that, In the nutrient solution circulation step, a differentiated nutrient solution supply mode is executed by controlling the variable frequency operation of the supply pump: During the photoperiod, maintain a continuous supply of sap to ensure that the crop's photosynthetic needs for water and nutrients are met. During the dark period, an intermittent liquid supply mode is adopted, with an interval of 15 minutes of liquid supply followed by 45 minutes of liquid cessation, in order to promote root respiration and prevent root hypoxia.

11. The planting method according to claim 9, characterized in that, In the light regulation step, differentiated spectral regulation is performed according to the crop growth stage: Early stage regulation after transplanting: On the 1st to 3rd day after crop transplanting, set the proportion of blue light to 30%-40%, red light to 50%-60%, and far-red light to 5%-15% to inhibit excessive growth and promote thick stems and root development. Rapid growth period regulation: 4-20 days after crop transplanting, set the proportion of red light to 70%-80%, blue light to 15%-25%, and far-red light to 3%-8% to promote leaf expansion and biomass accumulation. Pre-harvest regulation: 3-5 days before harvest, increase far-red light irradiation, setting the proportion of far-red light to 15%-25%, red light to 60%-70%, and blue light to 10%-20%, in order to regulate leaf morphology, improve leaf color, and reduce nitrate content.

12. The planting method according to claim 9, characterized in that, It also includes environmental feedback and control steps: The temperature, humidity, CO2 concentration and light intensity of each level are monitored in real time by a distributed sensor array. The sensor array is integrated into the side wall of the column of each cultivation rack and corresponds one-to-one with the planting level. The central control system receives monitoring data and compares it with preset thresholds; When any environmental parameter exceeds the set threshold, the corresponding environmental control equipment or LED light source is automatically adjusted to keep the fluctuation range of each level of microenvironment parameters within ±5% of the set value.

13. The planting method according to claim 8, characterized in that, It also includes the online nutrient solution control step: The EC value and pH value of the reflux nutrient solution are monitored in real time by an online detection and control unit located between the supply pump and the return tank. When the EC value or pH value deviates from the set threshold, the system automatically controls the replenishment of concentrated solution or acid / alkali solution to maintain the stability of the nutrient solution composition.

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