WO1983001888A1

WO1983001888A1 - Hydroponic system

Info

Publication number: WO1983001888A1
Application number: PCT/GB1982/000342
Authority: WO
Inventors: Kenneth Roy Dunn
Original assignee: Kenneth Roy Dunn
Priority date: 1981-12-05
Filing date: 1982-12-03
Publication date: 1983-06-09
Also published as: DK355983A; DK355983D0; JPS58502131A; AU1103183A; EP0096699A1

Abstract

A method of growing plants, either from seeds or seedlings, which comprises placing them in a receptacle (20) and moving the receptacle through successive zones (A, B, C, D, E) which provide conditions for germination of the seeds or growth of the seedlings, and growth of the mature plants, and then removing the mature plants from the receptacle. The apparatus comprises a series of inclined racks (12, 14) each capable of receiving a receptacle (20) containing the seeds or plants and each divided into a number of successive zones (A, B, C, D, E) in which the plants may be exposed to the necessary environmental conditions for the particular stage of growth in that zone.

Description

HYDROPONIC SYSTEM

This invention relates to a hydroponic system, and in particular a method and apparatus for growing plants from seed on a continuous basis.

Hydroponics may be described as a method of growing plants or other vegetation without the use of soil and is well-known as such. Apparatus for putting hydroponics into commercial operation is also known, for example see our Patent Hos. 1,597,111 and 1,597,112 However, current apparatus operates essentially on a batch system whereas there is a need, particularly in the production, for example of fodder for animals, of a continuous system which will operate independently of the external environment where necessary, to produce a regular and continuous supply of herbage. The invention seeks to provide a method and apparatus for such a continuous system.

In its broadest aspect the present invention provides a method which comprises taking the seeds of a desired plant, placing them in a receptacle and moving the receptacle through- successive zones which provide conditions for germination of the seeds, growth of the seedlings and growth of the mature plants and then removing the mature plants from the receptacle. The invention further provides an apparatus which comprises a series of inclined racks each capable of receiving a receptacle containing seedsor plants, each divided into a number of successive zones in which the plants may be exposed to the necessary environmental conditions for the particular stage of growth in that zone.

According to the present invention there is also provided a receptacle for receiving seeds and/or plants comprises a tray having a drain hole, the drain hole being fitted with a drain control which comprises a pair of tubes concentric to one another, the one being a slidable interference fit within the other, the inner and outer tubes having orifices which may be brought into partial or complete register with one another by relative circumferential movement between the tubes, and the outer tube having a further level determining orifice or orifices.

The inner tube fits in fluid sealing relationship within the drain hole of the tray and the orifices within the tubes which may be brought into partial or complete register are preferably located below the level of seeds and/or plants within the tray. In this way, the orifices of the drain control may be moved out of register so that fluid will not pass through them and the tray filled with a suitable soaking luid, for seeds. By adjusting the relative positionsto the orifices on the tubes it is then possible to allow the tray to drain off liquid over a period of minutes or hours as desired. The tube may also have further orifices higher up from the drain hole level to set the overall maximum liquid height within the tray. Preferably these latter orifices may ^'be provided with mesh or other form of filter system so that seeds do not wash away should the liquid overflow. Furthermore, the relative

circumferential movement- between the inner and outer tube may be restricted by means of a stop and slot arrangement so that the tubes may be moved between two pre-set positions which simplifies the operation in practice.

The invention will be described further, by way of example, with reference to the accompanying drawings, in which:-

Figure 1 is a perspective view of a rack apparatus according to the invention;

Figure 2 is a diagramatic indication of the nutrient supply and drainage system for the apparatus of Figure 1;

Figure 3 is a plan view of a suitable seed and/or plant receptacle;

Figure 4 is a plan view of an insert for the receptacle of Figure 3; .

Figure 5 is a sectional view on the line A-A.of Figure 4; and Figure 6 and 7 are perspective views of drain contro systemsfor use with the receptacle of Figure 3.

Referring now to the drawings, and in particular Figures 1 and 2, there is illustrated a rack system generally designated 10 fo^'r receiving seed and/or plant receptacles. The apparatus 10 comprises a number of inclined racks 12 sloping from right to left and a number of inclined racks 14 sloping from left to right (as viewed in Figure 1) . The racks 12 and 14 traverse the length of the apparatus which is divided length wise into a number of zones, in this case five, the purpose of which will be described more fully hereinafter. The apparatus illustrated in Figure 1 is of a width to allow three sets of receptacles to be entered on any given rack 12 and 14 side by side, but naturally the width of the apparatus is a matter of choice and it

O may be made narrower or wider as desired and according to the space available.

Prefered forms of plant receptacles will be ; described hereinafter with reference to Figures 3 to 5 6, but in general the plant receptacle may comprise any tray capable of receiving plants having some form of drain hole to allow spent or excess nutrient to or seeds be removed. Trays containing young plants are entered on the right hand side (as viewed in Figure 1) of 0 the apparatus onto the rack 12 and at the left hand side of the apparatus orix) theracks 14. The apparatus is divided into five zones designated A, B, C, D, and E respectively. Each zone is of such a length as to hold a certain number of trays of plants, and in many cases 5 the zones may hold equal numbers of trays of plants. .Each zone A to E is provided with spray or drip means 16 for providing nutrient to each tray of plants within that zone and with drain means 18 for removing spent or excess nutrient from each tray. In Figure 2, 0 for clarity, zones A and C show only drain means and the zone B shows only inlet means but it will be appreciated that both inlet and drain means are present at each zone, so that each tray in the system can have nutrient fed to it and removed from it. Often, as a 5 matter of convenience, the zones correspond to one days growth in the plant growing cycle.

Therefore, in use, trays of young plants may be loaded onto the racks 12 and 14 at day one where they are given an amount of concentration of nutrient solution 0 appropriate for that stage of growth. At day two the tray is moved down into zone B with fresh trays being added at zone A. The nutrient amount andconcentration at zone B may be different from that of zone A according to the growth cycle of the particular plant being grown. 5 Similarly at day three the trays move on to zone C and so on until at the end of five days trays containing mature plants may be removed from zone E. It will be appreciated that the plants move from zones A through to E when they are placed on the trays 14 but for plants in trays placed on racks 12 the plants move from zone

E through to zone A. However, since each rack 12- and 14 within each zone A to E^"' is provided with an- independent feed and discharge system trays moving in both directions along the apparatus of the invention can be accomodated.

Each of the inlet spray or drip feed means 16 may be supplied from a separate tank of nutrient fluid which may be pure water or may have growth aiding nutrients or other chemicals within it according to normal hydroponic practice. The conditions can be selected at each stage in the plants growth to favour maximum yields.

The light necessary to induce growth may be provided, for example, by means of fluorescent tubes situated either within the apparatus of Figure 1 above each of the racks or, where the apparatus is not too wide, at either side of the apparatus shining into the racks. Alternatively or in addition the apparatus may be situated so as to receive sunlight either externally or through glass, transparent plastics materials or the like. Referring now more particularly to Figures 3 to 6 it can be seen that a receptacle 20 for receiving seeds and/or plants comprises a ribbed tray 22 having a central drain orifice 24. An insert 26 is intended to fit within the receptacle resting on the ribs as can be more clearly seen from Figure 5. The insert 26 may carry radial veins 28 dividing the area -of the tray into a number of portions which facilitates removal of the plants when they are fully grown. The central drain orifice 24^" has fitted within it a drain

OMP control generally designated 30 which comprises an inner and outer concentric tube, respectively 32 and 34 which are a sliding interference fit with one another. The inner tube 32 is fitted in fluid sealing relationship with the drain orifice 24 and projects upwardly into the tray 22. The inner tube 32 also carries a number of drain orifices 36 which may be brought into complete or partial register with similar orifices 38 in the outer tube 34. A stop 40 may be fixed to the inner tube 32 to cooperate with a corresponding cut-out or slot 42 in the outer tube 34 to limit the relative circumferential movement between the two tubes between two extreme pre-determined positions. Further up the outer tube 34 there may be provided further overflow drain orifices 44 which may be protected by filter means such as a mesh 46. Furthermore, the top of the tube 34 may be left open to provide a large overflow to prevent flooding of the tray 22 should nutrient be supplied at- too greater- rate for the orifices 44 to be able to cope,σr the orifices become blocked The receptacle 20 and drain control 30 may ideally be used with the rack apparatus described above but may also be used for other purposes. In use, seeds may be placed on the insert 26 which is spaced from the bottom of the tray into two by means of the ribs in the tray. The drain control may be turned so that the orifices 36 and 38 are out of register and the tray filled with a suitable liquid, for example a dilute hydrogen peroxide solution suitable for removing the coats from barley seeds, the drain control 30 may then be turned so that the drain orifices 36 and 38 are partially in register to affect a slow rate of drainage of the liquid from the tray. The tray may then be left unattended to allow the drainage of liquid to complete itself. If the trays 20 are used within the

apparatus of Figures 1 and 2 the drain control 30 may be pre-set to give a predetermined drain rate. This allows the use of a drip feed input of nutrient through the means 16 rather than a■ spray. The drip feed may be timed so as to fill the tray, the drain control then allowing the tray to empty over a further period of time followed by the drio feed replenishing the tray and^' the process being repeated. Where desired, the relative times can be adjusted so that the drip feed need only fill the tray once in each zone. As an example, the apparatus and method of the invention may be used to produce usable barley from seed in a seven day cycle as follows. Firstly barley seed is placed in a tank filled with an aqueous solution containing chemicals to encourage germination, for example hydrogenperoxide in the case of barley to remove the coat from the seeds. The seeds remain in the tank for one day with some agitation. After this the liquid is drained from the tank and .may be filtered and re-used after checking and replenishing chemical concentrations as necessary. The wetted barley seeds are placed on the inserts 26 of the receptacles 20 between the segment veins 28. The trays 20 are placed into a germination cabinet which is an environmentally controlled cabinet having light and humidity conditions especially adapted to encourage germination of the seeds. The cabinet may have drip spray means together with a drainage system as necessary for the particular seeds.

After two days the trays are removed from the germination cabinet and placed on to the racks 12 and 14 of the apparatus of Figure 1, removing previously finished trays from the lower end of the respective racks to make room. During initial loading of the racks at the start of the apparatus temporary stops may be provided for the first five days as the racks move

OMPI from zones A through to E. After the fifth day on the racks trays of mature plants may be removed and the plants used in their entirety, including roots, or with certain forms of herbage the plants may be cut and returned to the racks for further growth.

Once the system of the invention has been set in operation fresh seeds are treated every day and a crop of mature herbage is again obtained every day in a continuous process. An apparatus such as that depicted in Figure 1 of the accompanying drawings is capable of producing yields in the order of a ton of herbage daily occupying the space of approximately eight meters by 3 meters in area, and at a height of less than two and a half meters. Natural^, larger units will produce greater yields.

It can therefore be seen that the -method and apparatus according to the invention provides a system for producing continuous high yields of herbage,independently of the external environment where necessary in a reliable and economical manner.

Referring now to Figure 7, an alternative form of drain control system is illustrated. As with the system illustrated in Figure 6, there is a tube 32 fitted in fluid-sealing relationship with the drain orifice 24 of the receptacle 20,whidι projects upwards into the insert 26.The tube 32 carries a syphon tube 50 passing through a suitable hole 52 in the tube. One end 54 of the syphon tube leads to drain, whilst the other end 56 depends below the level of the insert tray^' 26. A small bleed orifice 58 is also provided in the tube 32 adjacent the end 56 of the syphon tube and just above the base of the receptacle 20.

The operation of the drain control system of Figure 7 is as follows. Nutrient liquid may be

OMPI inserted into the receptacle 20 as previously described and it will fill until it reaches the level of the top of the syphon tube 50 at which point the syphon will operate draining out the liquid at a rate governed by the bore of the syphon tube. The liquid will be syphoned to drain until it is below the level of the insert 26 carrying the plants and/or seeds, thereby providing a flood and drain system. The bleed orifice 58 serves to drain off any remaining liquid below the end 56 of the syphon tube. The size of the bleed orifice 58 is such that it does not interfere with the normal filling of the receptacle 20 or with the emptying action of the syphon 50. The positioning of the orifice 58 adjacent the inlet end 56 of the syphen ensures that the orifice 58 is swept clear of debris and does not become blocked. Different sizes of syphon tube 50 may be provided to give different emptying times of the receptacle 20 as required with different plants or herbage. The maximum fill level id determined by the height of the tube 32, as before.

The receptacles may be used with inserts specifically shaped to receive, e.g., blocks or units of pre-see'ded growing medium such as mineral wool.

Claims

CLAIMS :

1. A method of growing plants which comprises taking seeds and/or plants, placing them in a receptacle and automatically moving the receptacle through successive zones which provide conditions for germination of the seeds and/or growth of the seedlings, and growth of the mature plants, and then removing the mature plants from the receptacle.

2. An apparatus for growing plants which comprises a series of inclined racks each capable of receiving a- receptacle containing seeds or plants, each divided into a number of successive zones in which the plants may be exposed to the necessary environmental conditions for the particular stage of growth in that zone.

3. A receptacle for receiving seeds and/or plants which comprises a tray having a drain hole, the drain hole being fitted with a drain control means which comprises a pair of tubes concentric to one another, but one being a slidable interference fit within the other, the inner and outer tubes having orifices which may be brought into partial or complete register with one another or relative circumferential movement between the tubes, and the outer tube' having a further level determining orifice or orifices.

4. A receptacle for receiving seeds and/or plants which comprises a tray having a drain hole, the drain hole being fitted with a drain control which comprises a sypon tube arranged in the drain hole such that the receptacle can be filled to a first predetermined level corresponding to the top of the syphon tube after which the syphonwill operate to reduce the liquid level to a second predetermined level, the bore of the syphon being chosen so that a desired time elapses between the first and second predetermined levels.

5. An apparatus as claimed in claim 2 in which a series of inclined racks slope from left to right and a

-^\JS.E_- ^{* OMH} further series of inclined racks slope from right to left, mounted one above the other, so that the headroom of the lower rack is progressively increased as the receptacle traverses it.

6. An apparatus as claimed in claim 5 in which a plurality of series of racks are mounted one above the other, each series of racks being provided with lighting means, water and/or nutrient feeding means, and drain means.

7. An apparatus as claimed in claim 6 in which the feeding means to each series of inclined racks is divided up into zones along the length of the rack so that different feeding solutions can be dispensed to each zone.

8. An apparatus as claimed in claim 7 in which each zone has an associated drain system which may collect the drained feed solution individually or return it all to a common sump hole for disposal or recycling.

9. An apparatus as claimed in claim 2 in which the receptacle has a drain hole and a ribbed base on which is mounted an insert capable of carrying. the plants so that they are held clear of the base of thereceptacle.

10. An apparatus as claimed in claim 9 in which the insert carries radial vanes dividing thearea of the tray into a number of portions which facilitate the removal of the plants when they are fully grown.