DEVICE FOR PROMOTING THE GROWTH OF PLANTS

Abstract

The invention relates to a device and to a method for promoting the growth of plants (8), comprising a conveyor belt (2) which can be moved along a conveyor path (1) for transporting, at least in sections, plants (8) which are at least temporarily supplied with nutrients by a nutrient supply (9) and illuminated by an illumination unit (10) during movement along the conveyor path (1). The conveyor path (1) is at least approximately horizontal in at least one first section (7), and is at least approximately vertical in at least one second section (6). The technical solution described is characterized in that the plants (8) are at least temporarily fixed relative to the conveyor belt (2) during transport along the conveyor path (1) such that at least parts of roots of the plants (8) protrude into a region (19) located below a lower surface of the conveyor belt (2), while at least parts of leaves and/or fruits of the plants (8) protrude into a region (20) located above an upper surface of the conveyor belt which opposes the lower surface. As a result of the use of modularly constructed conveyor belt ribbons, growing periods of an arbitrary length are adjusted or an adapted required space of the plant assembly is ensured.

Claims

1. A device for promoting the growth of plants, the device comprising: a conveyor belt which can be moved along a conveyor path and is configured for transporting, at least in sections, plants which are at least temporarily supplied with nutrients by a nutrient supply and illuminated by an illumination unit during transport along the conveyor path, the conveyor path being at least approximately horizontal in at least one first section, and being at least approximately vertical in at least one second section, characterized in that the plants are at least temporarily fixed relative to the conveyor belt during transport along the conveyor path such that at least parts of roots of the plants protrude into a region located below a lower surface of the conveyor belt, while at least parts of leaves and/or fruits of the plants protrude into a region located above an upper surface of the conveyor belt which opposes the lower surface, and in that the nutrient supply comprises, in the region located below the lower surface of the conveyor belt, a supply unit for aeroponically supplying the plants with nutrients, the supply unit misting a nutrient medium and/or discharging said nutrient medium towards the lower surface of the conveyor belt.

2. The device according to claim 1, characterized in that the conveyor belt comprises, at least in regions, a carrier material in which the plants are fixed at least temporarily during transport along the conveyor path.

3. The device according to claim 1, characterized in that the conveyor path comprises a lower deflection point between two at least approximately vertical sections.

4. The device according to claim 1, characterized in that the conveyor path comprises an upper deflection point between two at least approximately vertical sections.

5. The device according to claim 1, further comprising an at least partly automated fitting unit which fits the conveyor belt with plant seeds and/or seedlings.

6. The device according to claim 1, characterized in that at least one section that is illuminated by the illumination unit and one section that is not illuminated are arranged along the conveyor path.

7. The device according to claim 1, characterized in that the conveyor path 4 comprises two at least approximately vertically extending sections and two horizontal sections that each connect the vertical sections, at least one supply unit for aeroponically supplying the plants with nutrient medium being arranged between the opposite lower surfaces of the conveyor belt moved along the conveyor path.

8. The device according to claim 1, characterized in that the conveyor belt comprises a plurality of movably interconnected slats.

9. The device according to claim 1, characterized in that the nutrient supply has at least one immersion bath containing nutrient solution, at least roots of the plants being guided through the immersion path at least in sections along the conveyor path.

10. The device according to claim 1, further comprising at least adjustment unit to change the distance between a section of the conveyor path extending at least approximately vertically from top to bottom and a section of the conveyor path extending at least approximately vertically from bottom to top.

11. The device according to claim 1, characterized in that a module is formed by a section of the conveyor path extending at least approximately vertically from bottom to top and a section of the conveyor path extending at least approximately vertically from top to bottom, and a number of modules required to achieve a growing phase of the plant are interconnected by interface elements, depending on the plant to be grown, in particular the space necessary for growth of the plant.

12. The device according to claim 11, characterized in that at least one illumination unit is integrated into the module.

13. The device according to claim 11, characterized in that two modules are connected by an at least approximately horizontally extending section of the conveyor path, the length of the section being selected on the basis of the plant to be grown.

14. The device according to claim 11, produced by assembling at least two pre-grouped modules.

15. The device according to claim 1, characterized in that an at least partly automated harvesting unit is provided, which removes plants from the conveyor belt at least in part.

16. The device according to claim 1, characterized in that a cleaning and/or sterilization unit for cleaning and/or sterilizing the conveyor belt is arranged in a region of the conveyor path located between a region in which the plants are removed from the conveyor belt at least in part and a region in which plant seeds and/or seedlings are fixed on the conveyor belt.

17. A device for promoting the growth of plants, the device comprising a conveyor belt which can be moved along a conveyor path and is configured for transporting, at least in sections, plants which are at least temporarily supplied with nutrients by a nutrient supply and illuminated by an illumination unit during transport along the conveyor path, the conveyor path being at least approximately horizontal in at least one first section, and being at least approximately vertical in at least one second section, characterized in that the plants are at least temporarily fixed relative to the conveyor belt during transport along the conveyor path such that at least parts of roots of the plants protrude into a region located below a lower surface of the conveyor belt, while at least parts of leaves and/or fruits of the plants protrude into a region located above an upper surface of the conveyor belt which opposes the lower surface, a module being formed by a section of the conveyor path extending at least approximately vertically from bottom to top and a section of the conveyor path extending at least approximately vertically from top to bottom, and a number of modules required to achieve a growing phase of the plant being interconnected by interface elements, depending on the plant to be grown, in particular the space necessary for growth of the plant, and at least two modules being connected by an at least approximately horizontally extending section of the conveyor path.

18. A method for promoting the growth of plants, in which the plants are moved along a conveyor path by a conveyor belt and are at least temporarily supplied with nutrients by a nutrient supply and illuminated by an illumination unit during movement along the conveyor path, the plants being moved at least approximately horizontally in at least one first section of the conveyor path and at least approximately vertically in at least one second section of the conveyor path, characterized in that the plants are at least temporarily fixed relative to the conveyor belt during transport along the conveyor path such that at least parts of roots of the plants protrude into a region located below a lower surface of the conveyor belt, while at least parts of leaves and/or fruits of the plants protrude into a region located above an upper surface of the conveyor belt which opposes the lower surface.

19. The method according to claim 18, characterized in that while being moved at least approximately vertically, the plants are at least temporarily aeroponically supplied with water and/or nutrients.

20. The method according to claim 18, characterized in that while being moved at least approximately horizontally, the plants are at least temporarily hydroponically supplied with water and/or nutrients.

21. The method according to claim 18, characterized in that the entire conveyor path is at least temporarily illuminated.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In the following, the invention will be described in more detail, without limiting the general inventive concept, on the basis of embodiments and with reference to the drawings, in which:

[0029] FIG. 1 is a schematic view of a device for automated plant cultivation according to the invention;

[0030] FIGS. 2a-2b depict a conveyor belt suitable for a device for automated plant cultivation; and

[0031] FIG. 3 is a schematic view of a demonstrator of a plant cultivation system according to the invention, used for a plant cultivation experiment.

DETAILED DESCRIPTION

[0032] FIG. 1 is a schematic view of a device for automated plant cultivation according to the invention. An essential feature of the device is that the plants 8 are fixed on the conveyor belt 2 during transport along the conveyor path 1, the roots of the plants 8 being located, at least for the most part, on the other side of the conveyor belt 2 in relation to the leaves. The dimensions of the conveyor path 1 and the movement speed of the conveyor belt 2 are selected such that the period of time over which the plants 8 are moved along the conveyor path 1, from placing a seed or seedling on the conveyor belt 2 to removal from the conveyor belt 2, corresponds to a growing phase of the corresponding plant 8.

[0033] In relation to the arrangement of the conveyor path 1, it is particularly important that the plants 8 fixed on the conveyor belt 2 are moved both upwardly and downwardly vertically in sections, while the plants are moved at least temporarily horizontally between the individual vertical path sections 6, in particular in the region of the upper and lower deflection points 4, 5.

[0034] At the start of the conveyor path 1, a fitting unit 12 is provided, by means of which the receiving elements 3 of the conveyor belt 2 are each fitted with a seedling 8. The receiving elements 3 according to the described embodiment each have a carrier material 18, preferably rock wool, in which the plant 8, in particular the roots thereof, is fixed. An essential feature is that the roots of the plants 8 are located in a region 19 below the conveyor belt 2, while the leaves extend in a region 20 above the conveyor belt 2. The regions 19, 20 in which the roots and the leaves are respectively located are thus spatially separate from one another. Furthermore, while the plants 8 are moved along the vertical sections 6 of the conveyor path 1, the roots are located in a ventilated space in which the plants 8 undergo an aeroponic moistening and nutrient supply process 9a.

[0035] On account of the specific design of the conveyor path 1, the conveyor belt 2 alternately moves the plants 8 vertically as far as an upper deflection point 4 and then down again towards a lower deflection point 5. As soon as the plants 8 reach the lower end of the vertical path 6, the plants are moved horizontally at least over a short path section 7. During the movement in the region of the lower deflection point 5, the carrier material, together with the roots of the plant 8 arranged therein, is immersed in an immersion bath 9b such that the plants 8 are hydroponically moistened and supplied with nutrients. Following the at least momentary horizontal movement, the plants 8 are moved once again over the next two vertical path sections 6 of the conveyor path 1, with the upper deflection point 4 therebetween. While the plants 8 are being moved along the vertical path sections 6, the plant roots once again undergo aeroponic moistening 9a on the lower surface of the conveyor belt 2.

[0036] A section of the conveyor path 1 consisting of, firstly, two vertical sections 6 in which the plants 8 are moved from bottom to top and then from top to bottom and, secondly, a deflection point 5 arranged between the vertical sections, is referred to as a module or cultivation module. The configuration of the module and the setting of the speed of the conveyor belt 2 are such that the plants 8 cycle through a module of this kind within 24 hours. An overall system is in turn composed of the number of modules required to achieve a complete growth phase of the given plant 8.

[0037] Furthermore, the device for automated plant cultivation has an illumination unit 10 designed such that while being moved along the conveyor path 1, the plants 8 are partly illuminated with artificially generated light and partly not illuminated. In the embodiment shown in FIG. 1, the plants 8 are always illuminated when they are being moved downwards along a vertical path section 6 between the upper deflection point 4 and the lower deflection point 5. However, a shaded phase 11 is provided when the plants 8 are being moved along a path section extending from bottom to top. In this connection, the illumination unit 10 is covered such that the plants 8 are not illuminated. In principle it is conceivable to adapt the type, intensity and duration of the illumination to the given type of plant. In each case, the illumination is controlled or is appropriately adjusted by means of sensors and a control unit. In the embodiment shown in FIG. 1, LED panels that are arranged opposite respective downwardly extending vertical path sections 6 are provided as illumination units 10.

[0038] Moreover, the device for automated plant cultivation shown in FIG. 1 has an adjustment unit 21 such that the distance between the individual modules, which each consist of two vertical path sections 6 and an upper deflection point 4 arranged therebetween, can be adapted to the growth in size of the individual plants 8. As can be clearly seen in FIG. 1, the size of the plants 8 increases while they are being transported along the conveyor path 1. To the extent to which the plants 8 grow, the distance between the individual modules is increased and the illumination is adapted to the change in the light requirement on account of the larger amount of greenery of the plants 8. As a complement to the measures, the conveyor belt 2 is also designed such that the distance between the individual receiving elements 3 in which the plants are fixed can be changed on the basis of the plant growth. A specific embodiment of a conveyor belt 2 that can be adapted to the growth in size of the plants will be described in connection with FIG. 2.

[0039] At the end of the conveyor path 1, an automated harvesting unit 13 is provided, which removes, from the circulating conveyor belt 2, the plants 8 that have grown to normal size. Directly upstream of the harvesting unit 13, the conveyor belt 2 is deflected once again and then circulates back to the fitting unit 12. To ensure the required cleaning and sterilization of the conveyor belt 2, along the path between the harvesting unit 13 and the fitting unit 12 the conveyor belt 2 is first cleaned and then undergoes surface sterilization by means of a steam sterilization system 14. The conveyor belt 2 thus returns to the fitting unit 12 in a fully cleaned and sterilized state, the fitting unit refitting the individual receiving elements 3 of the conveyor belt 2 with carrier material 18, at least provided that the material cannot be used multiple times, and with seeds or seedlings 8.

[0040] As shown in FIG. 1, it is advantageous if the individual receiving elements 3 are first fitted with carrier material 18, provided that the material cannot be re-used, and with a seed or seedling 8 in the fitting unit 12 or in an upstream process step, such that the already fitted receiving elements 3 can be placed on and/or fastened to the conveyor belt 2.

[0041] Generally, however, it is also conceivable for the receiving elements 3 to be integrated into the conveyor belt 2 or at least rigidly connected thereto such that the fitting unit 12 merely inserts a seed or a seedling 8 and, if required, fresh carrier material 18 into the receiving elements 3.

[0042] In both cases, it is possible for the receiving elements 3 to already have carrier material 18 into which seeds or seedlings 8 are inserted by the fitting unit 12, or for the individual receptacles 3 of the conveyor belt 2 to be fitted with a seed or a seedling 8 of which the roots are already in the carrier material 18.

[0043] FIGS. 2a-2b depict a portion of a conveyor belt 2 that can be adapted to the growth of the plants 8 while they are being conveyed along the conveyor path 1. It makes sense to adjust the distance between the individual receiving elements 3, as appropriate; this is because, as the plants 8 grow, in particular the leafy component increases, in the case of heads of lettuce for example, and thus the surface area requirement of the individual plants 8 also grows. For this reason, the individual receiving elements 3 of the conveyor belt 2 are suitably spread apart by means of mechanical elements such that the individual plant 8 has more space to grow and is sufficiently illuminated.

[0044] The above-described adaptation is achieved substantially by varying the distance between the receiving elements 3, in each of which a plant 8 or the roots thereof is/are fixed in the carrier material 18, on the basis of the time that the plants 8 have spent on the conveyor belt 2. Taking into consideration the extent and speed of the plant growth, the distances between the individual receptacles are increased while the plants 8 are being transported. In this connection, FIGS. 2a-2b show a portion of a conveyor belt 2, together with plants 8 fixed thereto, in two different growth stages of the plants 8. While the plants 8 shown in FIG. 2a are still at the start of the conveyor path 1 and are relatively small, the plants are about to be harvested in the state shown in FIG. 2b and have therefore reached a corresponding size. To take this growth in size into account, the distances between individual receiving elements 3 are considerably larger in FIG. 2b than the corresponding distances in FIG. 2 a).

[0045] In the embodiment shown in FIGS. 2a-2b, the conveyor belt 2 has conveyor chains 15, to which the individual plant receptacles 3 are fastened by means of suitable, elastic transport belts 16. The transport belts 16 are designed such that both the distance A between the parallel transport belts 16 and the distance B between the receiving elements 3 fastened to a given transport belt 16 can be changed. While a change to the distance A can be achieved by moving the transport belts 16 outwards, the distances B between the individual receptacles 3 are changed by elastically elongating the transport belts 16 in the longitudinal direction. Similarly, an increase in the distances to the receiving elements 3 not directly connected to the transport belts 16 is achieved by providing, between the receiving elements 3, elastic connection elements 17 that are accordingly elongated when the transports belts 16 are moved.

[0046] The receptacles 3 can be fastened to the transport belts 16 by hooking at least part of the receptacles 3 into the transport belts 16. It is also conceivable for at least part of the receptacles 3 to be rigidly connected to one transport belt 16 each.

[0047] As can be seen in FIG. 2a, however, not all the receptacles 3 have to be directly connected to a transport belt 16 but can also be indirectly connected to at least one transport belt 16 via other receptacles 3 by means of elastic connections 17. As the transport time of the plants 8 increases, the transport belts 16 are moved apart and longitudinally elongated, for example by coiling the transport belts around drums that are moved along the conveyor path by means of the transport mechanism, such that the distances between the receptacles 3, together with the plants 8 therein, increase. In this connection, it is also conceivable for elastically elongatable elements 17 to be provided merely between the individual receiving elements 3 and for merely the outer receptacles 3, i.e. the receptacles 3 located at the corner points in FIG. 2a, to be pulled outwards. Similarly, the receptacles 3 could be arranged at different positions in an elastic net, or a corresponding elastic net could form at least part of the conveyor belt 2, it being possible to pull the net apart, as required, in particular on the basis of the plant growth, in order to change the distances between the receptacles 3, as required.

[0048] Furthermore, it is conceivable for the individual receptacles 3 not to be moved as a result of the movement of elastic connection elements 17, but for the individual receptacles 3 to be individually actively movable. Irrespective of the type of selected mechanism, it is essential that the distances between the individual receiving elements is changed both in the conveying direction and perpendicular thereto in order to meet the increasing space requirement of the plants.

[0049] To check the technical feasibility and to prove the advantages of the solution according to the invention, a demonstrator shown schematically in FIG. 3 was constructed. The demonstrator has a conveyor path 1 having a conveyor belt 2 that circulates in an oval shape and includes two vertical path sections 6 and two horizontal path sections 7, one in the region of the upper deflection point 4 and another in the region of the lower deflection point 5. The horizontal path sections 7 of the conveyor path 1 are relatively short on account of the design of the demonstrator and are limited to the particular inversion region of the conveyor belt 2.

[0050] The conveyor belt 2 has slats made of a plastics material, preferably polyvinyl chloride (PVC), which are in the form of roller shutter elements and on which the plants 8 are arranged such that the roots protrude into a region 19 below the conveyor belt 2, while the leaves and/or fruits protrude into a region 20 above the conveyor belt 2. A nutrient supply unit 9 including means for aeroponic nutrient supply 9a is located below the conveyor belt or within the conveyor belt 2 circulating in an oval-like manner. In the embodiment shown, the aeroponic nutrient supply unit has three spraying nozzles 24 in the form of non-drip four-jet heads connected to a recirculating water pump system having a nutrient solution tank 25.

[0051] The conveyor belt 2 is driven by means of an electric motor 22 that is connected to the conveyor belt 2 by means of a worm drive 23.

[0052] To illuminate the plants, illumination strips having LEDs are provided as illumination units 10 in the region 20 above the conveyor belt and in parallel with the vertical path sections 6. The drive motor 22 and the illumination strips serving as illumination units 10 are connected to a central control unit 26, which adapts both the illumination and the speed at which the plants are moved along the conveyor path 1 to the requirements of the given plants being moved.

[0053] For example, illumination and dark or shaded phases can be varied in this way. The demonstrator shown in FIG. 3 was installed in a climatic chamber having variable climate control and was used for growth experiments on various lettuce varieties.

[0054] Starting with the demonstrator shown in FIG. 3, it is conceivable to use the demonstrator or an at least similarly designed device as a basic module for a plant cultivation system including a plurality of basic modules of this kind. It is essential here that it is again possible to provide, depending on the given requirements of a plant, a plant cultivation system which ensures that vertical and horizontal paths 6, 7 are arranged according to requirements and thus in an optimized manner.

[0055] Using the demonstrator shown in FIG. 3, a specific plant cultivation experiment was carried out. A professional pelletized lettuce variety (Expertise RZ) from the company Rijkzwaan was used as a seed material. In a first step, the variety was produced in a nutrient solution in a 2 cm rock wool block and under 120 mol/s/m.sup.2 of LED light (blue/dark red) for 11 days. In the period, the temperature was set to 27 C. with 65% humidity for 18 hours during the day and to 19 C. with 55% humidity for 6 hours at night. Accordingly, the illumination was switched on for 18 hours and switched off for 8 hours.

[0056] The seedlings were transferred to the demonstrator on day 12, the seedlings simultaneously being transferred in a 10 cm rock wool block for the hydroponic NFT cultivation (NFT: nutrient film technique). The illumination of around 135 mol/s/m.sup.2 was achieved by blue and dark-red LED light strips (GreenPower production module from the company Philips). A misting system (from the company Netafim) designed for 5 bar and with interval sprinkling was used for the aeroponic nutrient supply, with nutrient solution being sprinkled for a period of 5 seconds, and the sprinkling then being disabled for 4 minutes.

[0057] The pH value of the nutrient solution was set to between 5.5 and 6.5 by means of diluted 5% nitric acid, and the nutrient content was kept to 0.8-1.0 EC (electrical conductivity) by means of liquid fertilizer (from the company YARA).

[0058] For the entire cultivation phase, the plants underwent 360 degrees of rotation over the course of 24 hours by the conveyor belt being gradually moved. After 3 weeks of cultivation, the leaf biomass was weighed.

[0059] The results of the above-described plant cultivation experiment are set out below. After three weeks of cultivation in the demonstrator system, as shown in FIG. 3, a significant (t-test: 0.03) increase in leaf biomass of up to 25% was observed in comparison with standard hydroponic NFT cultivation with LED illumination. Furthermore, on account of the continuous orbitropic realignment, round and uniform heads of lettuce were formed. By contrast, the plants that were cultivated statically and horizontally on a vertical wall were strongly influenced by the gravitational field of the earth, and the heads were misshapen. It was thus shown that the embodiment according to the invention induces good plant growth.

LIST OF REFERENCE NUMERALS

[0060] 1 conveyor path [0061] 2 conveyor belt [0062] 3 receptacle [0063] 4 upper deflection point [0064] 5 lower deflection point [0065] 6 vertical path section [0066] 7 horizontal path section [0067] 8 plant [0068] 9 nutrient supply unit [0069] 9a aeroponic nutrient supply unit [0070] 9b hydroponic nutrient supply unit [0071] 10 illumination unit [0072] 11 shaded phase [0073] 12 fitting unit [0074] 13 harvesting unit [0075] 14 cleaning and sterilizing unit [0076] 15 conveyor chain [0077] 16 transport belt [0078] 17 elastic connection elements [0079] 18 carrier material [0080] 19 region below the conveyor belt [0081] 20 region above the conveyor belt [0082] 21 adjustment unit [0083] 22 electric motor [0084] 23 worm drive [0085] 24 spraying nozzle [0086] 25 nutrient medium tank [0087] 26 central control unit