WO1999049723A1

WO1999049723A1 - An improved hydroponic apparatus

Info

Publication number: WO1999049723A1
Application number: PCT/AU1999/000225
Authority: WO
Inventors: John Vella; James Vella
Original assignee: Leppington Speedy Seedlings And Supplies Pty. Limited
Priority date: 1998-03-27
Filing date: 1999-03-29
Publication date: 1999-10-07
Also published as: AUPP261598A0

Abstract

A hydroponic apparatus for prolonging a desired growth characteristic of a plant, comprises a vessel (10a) enclosing a pool (62) of nutrient solution and a plant supporting member (16a). Nutrient solution is recirculated between the plant supporting member (16a) and the pool (62) of nutrient solution so as to supply controllably the nutrient solution to the plant to meet the growth requirements of the plant for the prolongation of the desired growth characteristic. The plant supporting member (16a) includes a conically inclined surface adapted to support the roots of the plant, and the nutrient solution is supplied controllably to the conically inclined surface so as to contact the roots for absorption thereby. The plant supporting member (16a) includes a retaining wall (46a) descending spirally down the conically inclined surface and along which nutrient flows.

Description

1

AN IMPROVED HYDROPONIC APPARATUS FIELD OF INVENTION

The present invention relates to a hydroponic apparatus for plant cultivation and, particularly, to a hydroponic apparatus that can be used for maintaining or prolonging a desired growth characteristic of a plant.

BACKGROUND ART

Hitherto, systems for growing plants hydroponically have concentrated on providing long term improved cultivation and growth throughout the life of the plant. However, there has been little focus on adapting hydroponic technology for the purpose of specifically enhancing or prolonging a desired growth characteristic of a plant, such as the flowering period or fruiting period. Hydroponically mediated prolongation of the flowering period, for instance, may be particularly useful where a desirable outdoor plant in flower is to be transferred to an indoor environment and it is desired that the flowering period be maintained or prolonged whilst the plant is kept indoors.

Of the prior art, Australian Patent Specification No. 83,620/75 discloses both a means and a method for irrigating an aggregate which is designed to allow plant growth therein. A nutrient solution is carried into a support for the aggregate by the upward movement of air bubbles through a liquid conduit. Once inside the support, the nutrient spreads or percolates by a capillary-like action throughout the aggregate by virtue of a combination of liquid retentive qualities of the aggregate and gravity so as to keep all the aggregate wet with nutrient solution. However, a plant root support member is non-existent and flow of nutrient is not in a state of continual recirculation, thereby restricting the growth potential of plants grown in the hydroponic unit of specification No. 83,620/75.

US Patent Specification No. 3,451 , 1 62 discloses a hydroponic apparatus for growing plants wherein the roots are periodically flooded with a nutrient solution. The plant roots are supported in an inert material and nutrient solution flows under gravity through the inert material in accordance with a predetermined timing control system. The level of nutrient solution in a growth tray which supports the inert material is controlled by the amount of nutrient solution contained in depressions in a nutrient storage chamber.

Australian Patent Specification No. 37,348/93 discloses a hydroponic growing structure wherein a plant growing media (rock, soil, rockwood etc.) is either periodically flooded by means of a pump and then drained completely or subject to top feeding by a drip-system with draining. By virtue of the fact that none of the aforementioned prior art specifications disclose a hydroponic apparatus having a plant root support member which includes one or more channels along which nutrient solution continuously flows, these prior art hydroponic plant growth apparatus cannot provide the intimate contact between plant roots, support member and nutrient solution that is necessary for the purpose of specifically enhancing or prolonging a desired growth characteristic of a plant, such as the flowering or fruiting period.

Australian Patent No. 671 ,871 by the same inventors as that of the invention described herein discloses a hydroponic apparatus that is designed for prolonging a desired plant growth characteristic and which utilizes a conical plant root support member having a series of grooves directed downwardly from the apex of the conical member in equally spaced apart relationship. Although the apparatus is generally effective in continuously regulating the supply of nutrient solution to the plant roots, it has been found by the present inventors that significant improvements may be made to the operational efficiency of the apparatus by restructuring the plant root support member to enable, among other things, a more gradual and controlled flow of nutrient solution to the plant roots. It is therefore an object of the present invention to provide an improved hydroponic apparatus that can be used to prolong a desired growth characteristic of a plant. SUMMARY OF INVENTION According to the invention, there is provided a hydroponic apparatus for prolonging a desired growth characteristic of a plant, comprising a vessel having a nutrient solution storage means, a plant supporting means, and means for recirculating nutrient solution between the plant supporting means and the nutrient solution storage means so as to supply controllably the nutrient solution to the plant to meet the growth requirements of the plant for the prolongation of the desired growth characteristic, wherein the plant supporting means comprises a support member including a conically inclined surface adapted to support the roots of the plant, the nutrient solution being supplied controllably to the said conically inclined surface of the support member so as to contact the roots for absorption thereby, and wherein the support member includes dam means descending spirally down the conically inclined surface and along which nutrient flows. BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood and put into practical effect, reference will be made to the accompanying drawings, in which:-

Fig. 1 is a front elevational view of a hydroponic apparatus according to a preferred embodiment of the invention, Fig. 2 is a perspective view of the disassembled hydroponic apparatus of Fig. 1 showing its component parts,

Fig. 3 is a perspective inverted view of the plant root support member and associated delivery pipe of the hydroponic apparatus of Figs. 1 and 2, Fig. 4 is a top view of the plant root support member of Fig. 3, Fig. 5 is a bottom view of the nutrient solution container of the apparatus of Figs. 1 and 2, and Fig. 6 is a sectional view through a hydroponic apparatus according to another preferred embodiment of the invention, in which a typical nutrient solution level is shown. DESCRIPTION OF PREFERRED EMBODIMENT

The hydroponic apparatus of Figs. 1 to 5 includes a vessel 10 comprising a cover 1 2 and a base 1 4 which are adapted to fit together by the lower annular rim portion 1 3 of the cover 1 2 engaging with the upper annular lip portion 1 5 of the base 1 4. Enclosed by the vessel 10 are a plant root support member 1 6 and associated delivery pipe 38, a nutrient solution container 1 8, an aerator 20 and an associated valve 22 and piping 24 and 26. The vessel components 1 2 and 14 and the internal components 14,

1 6 and 1 8 are constructed of a non-corrosive material, such as plastic, glass or ceramic. Preferably, these components are made of high density polyethylene for long life and durability.

The container 1 8 fits snugly within the base 1 4 as shown in Fig. 1 by engagement of an upper annular shoulder portion 27 of the container with a correspondingly shaped shoulder portion 29 of the base 14. The main floor 25 of the container 1 8 is raised from the floor 30 of the base 1 4, and there is an elevated floor portion 31 of the container 1 8 which enables the aerator 20 to be located within the base 14 beneath the container 1 8.

The aerator 20 is supported on the floor 30 of the base 14 and is adapted to pump aerated nutrient solution up through the delivery pipe 38 for the support member 1 6.

The nutrient solution is held in the container 1 8 and air for aeration of the nutrient solution is pumped into an inlet air tube 28 of the aerator 20 and is fed through valve 22 to the flexible rubber pipe 24 which is sealingly connected to a tubular inlet port 34 (see Fig. 5) descending from the floor 25 of the container 1 8. One of the branch ends 35 of the T-pipe 26 is sealingly located within an enlarged diameter portion 36 of the tubular inlet port 34 and the other branch end 37 is sealingly connected to the delivery pipe 38 for the support member 1 6. Nutrient solution is pumped from the container 1 8 into the stem end 39 of the T-pipe 26 and is aerated with air ascending from branch end 35 to 37. The aerated nutrient solution emerges from the delivery pipe 38 through opening 40 preferably as a steady trickling bulb of liquid. Although not shown, the opening 40 may be protected from interference or ingress of roots by a surrounding cap. The nutrient solution trickles out of the opening 40 and down the outside of the delivery pipe 38 until it encounters the conical support member 1 6 for the roots of the plant. As shown in Figs. 3 and 4, the conical support member 1 6 includes a skirt portion 42 extending circumferentially from the lower end of the conical support member 1 6 and which enables the support member 1 6 to rest on the annular shoulder portion 27 of the container 1 8.

The support member 1 6 includes a dam means 46 descending spirally from adjacent the apex of the member 1 6 which traps and directs the nutrient solution emerging from the opening 40 into flowing therealong. The roots of a plant growing on the support member 1 6 may enter the channel or groove formed by the spiral dam means 46 or may otherwise contact the nutrient solution flowing down the support member 1 6 and absorb nutrient therefrom.

It is to be understood that the term "dam means" as used in the present specification is intended to refer to any means of trapping and directing nutrient solution as it flows down the support member 1 6 and that is formed so as to penetrate into or protrude from the inclined surface of member 1 6, such as may be achieved by a groove or channel cut into the surface of member 1 6 or by a retaining wall that projects upwardly from the inclined surface.

The spiral dam means 46 has, in this embodiment, four full turns and so nutrient solution flows more gradually down the support member 1 6 (i.e. via the spiral dam means 46) than would be the case if there were no spiral dam means but a plurality of equally spaced apart linear grooves descending from adjacent the apex of the conical support member or no grooves or the like at all.

The spiral dam means 46 is, in this embodiment, formed as a retaining wall that projects upwardly from the inclined surface of support member 1 6 and which is integrally moulded therewith.

Having the roots supported on conically shaped support member 1 6, ensures that the roots may be substantially evenly or randomly spaced apart so as to optimize absorption of the nutrient solution. The presence of the spiral dam means 46 ensures that the nutrient solution is also substantially evenly distributed in its downward flow over the support member 1 6 thereby assisting in providing for controlled supply of nutrient to the roots.

The supply of nutrient to the roots can also be controlled by variation of parameters associated with the pump.

After the nutrient solution has travelled down the support member 1 6 it reaches the skirt portion 42 from where it drains down through the drainage holes 48 and falls back into the container 1 8.

The cover 1 2 has a growth aperture 68 defined centrally within a dished portion 70 at the top of the cover 1 2 for enabling the stem of the plant to grow therethrough, and an air vent arrangement 49 formed around the aperture 68 for appropriate ventilation of the root system.

The gradual and controlled flow of nutrient solution from the opening 40 of the delivery pipe 38 down the spiral dam means 46 of support member 1 6 on which the roots are supported ensures that the desired growth requirements of the plant can be met.

The hydroponic apparatus of Fig 6 is similar to the apparatus shown in Fig 1 and, in the following description and the drawing of the apparatus of Fig 6, the same numerals used above to identify features of the apparatus of Fig 1 will be used to identify identical or functionally analogous features in the apparatus of Fig 6.

The hydroponic apparatus of Fig 6 includes a vessel 1 0a comprising a cover 1 2a with air vent 49a and stem growth aperture 68a, a base 14a, and a stand 50 which is adapted to have the base 14a fit thereon as shown. There is a clip-on mechanism 52 to secure the cover 1 2a to the base 14a, and the base 1 4a sits stabily on the annular shoulder 54 of the stand 50. Enclosed by the vessel 1 0a are (i) a plant root support member 1 6a substantially in the shape of a flat topped inverted cone with tubular riser 56, (ii) an associated flexible delivery pipe 38a sealably connected at its uppermost end with the tubular riser 56 so as to be in fluid communication therewith, (iii) an air pump 58 of the kind commonly used in fish tanks together with the necessary valves and piping 60 for fluid flow connection of the air pump 58 with branch end 35a of a T-pipe 26a, the lowermost end of the delivery pipe 38a being sealably connected to the other branch end 37a of the T-pipe 26a as shown.

The base 1 4a has a raised floor portion 64 that enables the air pump 58 to be located in a suitably sized cavity formed between the base 14a and stand 50, and from where it can pump aerated nutrient solution through the delivery pipe 38a for the support member 1 6a. The aerated nutrient solution emerges from the tubular riser 56 preferably as a steady trickling bulb of liquid or as required. The nutrient solution then trickles down the outside of the riser 56 and outwardly across the flat topped roof 66 of the inverted cone shaped root support member 1 6a from where it can supply roots of a plant growing thereon with nutrient solution whilst 8

flowing down the conically inclined side surface of the support member 1 6a.

The downward flow is controlled by dam means 46a descending spirally three and a half turns from the roof 66. The spiral dam means 46a traps and directs the nutrient solution into flowing therealong and, by having the roots in intimate contact with the sides of the support member 1 6a, optimizes the supply and absorption of nutrient solution thereto and hence optimizes the growth conditions. Nutrient solution reaching the skirt portion 42a at the bottom of the support member 1 6a drains through the drainage holes 48a and falls into the base 14a where there is a permanent pool 62 of nutrient solution.

This is a particularly advantageous system for achieving plant homeostasis during a period when the plant is expressing a desired growth characteristic, such as flowering. In such an instance, the flowering period can be maintained or prolonged, even whilst the plant is in an indoor environment.

Various modifications may be made in details of design and construction without departing from the scope or ambit of the invention.

Claims

1 . A hydroponic apparatus for prolonging a desired growth characteristic of a plant, comprising a vessel having a nutrient solution storage means, a plant supporting means, and means for recirculating nutrient solution between the plant supporting means and the nutrient solution storage means so as to supply controllably the nutrient solution to the plant to meet the growth requirements of the plant for the prolongation of the desired growth characteristic, wherein the plant supporting means comprises a support member including a conically inclined surface adapted to support the roots of the plant, the nutrient solution being supplied controllably to the said conically inclined surface of the support member so as to contact the roots for absorption thereby, and wherein the support member includes dam means descending spirally down the conically inclined surface and along which nutrient flows.

2. The hydroponic apparatus of claim 1 wherein the said dam means comprises a retaining wall that projects upwardly from the said inclined surface so as to trap and direct the flow of said nutrient solution therealong.

3. The hydroponic apparatus of claim 2 wherein the said retaining wall is integrally moulded with the said inclined surface.

4. The hydroponic apparatus of claim 1 wherein the said dam means completes between about three and about five turns of the said inclined surface. 10

5. The hydroponic apparatus of claim 1 wherein the said support member includes a skirt portion having drainage holes through which said nutrient solution returns to the said storage means.

6. The hydroponic apparatus of claim 1 , further including a cover, wherein the said nutrient solution storage means comprises a base for the said cover, the said cover and said base being adapted to fit together so as to form the vessel for enclosing the said support member.

7. The hydroponic apparatus of claim 6 wherein the said vessel includes air venting means.

8. The hydroponic apparatus of claim 6 wherein the said cover includes an aperture for enabling the stem of the said plant to grow therethrough.