GB2303286A

GB2303286A - Hydroponic equipment

Info

Publication number: GB2303286A
Application number: GB9615095A
Authority: GB
Inventors: Kevin Douglas Pearce
Original assignee: Individual
Current assignee: Individual
Priority date: 1995-07-20
Filing date: 1996-07-18
Publication date: 1997-02-19
Also published as: GB9615095D0; GB9514904D0

Description

HYDROPONIC EOUIPMENT Field of the Invention This invention relates to hydroponic equipment, i.e. to equipment for use in the hydroponic cultivation of plants.

A number of types of hydroponic equipment are currently available, but they all have limitations which the present invention seeks to overcome.

Summary of the invention According to the present invention there is provided hydroponic equipment in the form of a table which is of generally rectangular form in plan view and, in use, is disposed at a small inclination to the horizontal, the table being provided at the upper end of the incline with a weir over which nutrient solution can flow, and with a drainage outlet at the lower end of the incline.

This is in contrast with the tables which are currently used for what is known as the "ebb and flow" method of hydroponic cultivation, which include a central combined inlet and outlet such that nutrient solution is initially pumped on to the centre of the table so as to flow outwardly and then, when the pump has stopped, the nutrient solution drains into the centre of the table and out through the outlet.

It is also in contrast with the systems currently in use which include a plurality of inclined gulleys or channels along which the nutrient solution is caused to flow.

The length of the table is preferably of the order of two metres and the width thereof of the order of one metre. A rail preferably extends above the table, being disposed so that it extends longitudinally of the table and centrally thereof. A horticultural light is preferably mounted on this rail and is preferably movable along the rail by means of a light mover.

The table is preferably provided at its corners with fittings whereby it can be supported on legs of such lengths that the table is supported at the required inclination to the horizontal, typically 1 in 40. Upward extensions of the legs preferably serve as brackets for supporting the ends of the rail on which the light is carried.

The upward extensions of the legs may also be used as structural members for forming an enclosure around the area in which the plants are located, the walls and roof of the enclosure being afforded by strips of plastic material which, if desired, may have a reflective coating so as to maximise the illumination within the enclosure.

The table may be formed of rigid fibreglass, having inclined side walls and a peripheral reinforcing flange. The weir preferably extends for the full width of the table with the arrangement such that the nutrient solution is fed into a channel between the weir and the end proper of the table, and then flows over the weir such that the rate of flow of nutrient solution over the weir is substantially uniform over the width of the table.

Delivery of the nutrient solution into the channel is preferably effected by means of a pump which is arranged to operate either substantially continuously or intermittently dependent on the method of cultivation which is being practised. The rate of discharge of the nutrient solution into the channel will be controlled accordingly.

The drainage outlet through which the nutrient solution is discharged may be arranged so that the nutrient solution can flow continuously through the outlet into a reservoir from which the nutrient solution is withdrawn by the pump for return to the table.

Alternatively, the outlet may be provided with a control valve, for example, a solenoid-operated valve such that the drainage outlet is closed when the pump is operating and then, when the pump has ceased operation after pumping a predetermined volume of nutrient on to the table, the valve is opened to allow a controlled, gradual outward flow of the nutrient solution into the reservoir.

As a further alternative, the drainage outlet may be provided with an outlet pipe through which the nutrient solution is discharged under a siphonic action such that the outflow of nutrient solution will not commence until the level of the nutrient solution reaches a first predetermined level and will then continue until it has fallen to a second predetermined level.

Brief Description of the Drawings Figure 1 is a plan view of a table, Figure 2 is a transverse sectional view of the table at the outlet end of the table, Figure 3 is a longitudinal sectional view of the table, and Figure 4 is an end view of the table mounted on a supporting framework.

Description of the Preferred Embodiment The table 10 shown in the drawings is of generally rectangular form in plan view and is produced from rigid fibreglass or some other reinforced plastic material having the required strength characteristics. It has a peripheral, horizontal reinforcing flange 11 and inclined walls 12 extending along the sides and ends of the main planar area of the table 10.

At one end of the table 10, there is an up-standing projection 13 which extends the full width of the table 10 and, in use, forms a weir over which the nutrient solution is caused to flow. There is an inlet pipe (not shown) for the delivery of the nutrient solution into the channel 14 between the upstanding projection 13 and the adjacent end wall 12 of the table 10. The nutrient solution is delivered from a reservoir (which may be located beneath the table 10) by means of a pump (not shown) which is controlled in dependence on the method of hydroponic cultivation being carried out.

At the other end of the table 10, there is a central depression 15 which functions as a drainage outlet and which contains an outlet pipe (not shown) for the discharge of the nutrient solution into the reservoir. The table 10 is so mounted that it is inclined to the horizontal at an inclination of 1 in 40, though other inclinations may be adopted if required. It is to be noted that, in use, the upper edges of the side and end walls 12 extending around the table 10 will be disposed horizontally, while the base of the table 10 is inclined. The height of the end wall 12 at the lower end of the incline will thus be greater than the height of the end wall 12 at which the nutrient solution is introduced.

Nutrient solution introduced into the channel 14 will thus flow over the weir afforded by the up-standing projection 13, flow the length of the table and will then enter the drainage outlet 15. If desired, the drainage outlet 15 will contain a filter or strainer to remove any debris from the nutrient solution before it is returned to the reservoir.

The inlet pipe may discharge the nutrient solution at a number of spaced positions across the width of the table 10 but, in any event, the rate at which the nutrient flows over the weir will be substantially uniform across the full width of the table 10 and the rate of flow of the nutrient solution will thus be consistent throughout the full area of the table 10.

Fittings (not shown) are provided at the four corners of the table 10 for the connection of supporting legs 16 which are of such length that the table 10 is supported at the required inclination of, for example, 1 in 40. The fittings (not shown) also provide for the connection of inverted U-shaped brackets 17, one at each end of the table 10. These brackets 17 support a rail 18 which extends centrally of the table 10 from one end to the other. A horticultural light (not shown) is mounted on this rail 18 and is movable along the length of the rail 18 by means of a standard light mover (also not shown).

The brackets 17 and the rail 18 can be used as support members for the formation of an enclosure above the table 10 produced by means of plastic strip or sheet. The plastics material may also serve to maintain a controlled atmosphere within which the plants are cultivated, particularly if carbon dioxide is injected into the enclosure.

An advantage of the particular size of table is that, with a standard 400 watt horticultural light and a standard 2 metre light mover, the illumination which is obtained is equivalent to a radiation level of 40 watt per square foot, i.e. optimum growing conditions. The area of the table is thus the maximum area which can effectively be illuminated by one standard horticultural light.

A commercial grower will thus have a plurality of tables, each illuminated by a standard horticultural light. The tables may be linked together so that they receive nutrient from a common reservoir and discharge it back into the common reservoir. The number of pumps which are used will depend on the capacities of the pumps and the relative positions at which the pumps are located.

Each table has an in-built slope and can be used when carrying out any of the standard hydroponic techniques, for example, when using the nutrient film technique, when using "Rockwool" slabs (either on a nutrient film principle or with drippers), when using media culture such as clay pebbles (again either on a nutrient film technique or when using drippers) or when using an "ebb and flow" technique with either a siphon action or a solenoid-operated valve in the discharge outlet.

In an alternative arrangement to that shown in the drawings, a number of tables are provided. They are mounted on rails to form a continuous growing area which, for commercial growers, provides a more costeffective way of setting out multiple units. The nutrient solution from the drainage outlet 15 of one table can thus flow directly into the channel 14 of the next table.

If a table 10 is covered with a growing medium, such as large expanded clay pebbles, the plants can simply be planted out in the growing medium and capillary action will carry the nutrient solution, which is flowing over the full area of the table 10 because of the 1 in 40 inclination of the table 10, to the roots of the plants. Fresh nutrient solution is always effectively pushing the stale nutrient solution down the incline to the drainage outlet 15 at the lower end of the growing area.

This means that, if desired, the pump can be operated so as to pump nutrient solution continuously into the channel 14 to flow over the weir afforded by the up-standing projection 13 without any problems caused by low oxygen levels because the running action of the solution continuously replenishes the oxygen supply.

Claims

Claims:

1. Hydroponic equipment in the form of a table which is of generally rectangular form in plan view and, in use, is disposed at a small inclination to the horizontal, the table being provided at the upper end of the incline with a weir over which nutrient solution can flow and with a drainage outlet at the lower end of the incline.

2. Hydroponic equipment as claimed in Claim 1, in which the length of the table is of the order of two metres and the width of the table is of the order of one metre.

3. Hydroponic equipment as claimed in either of the preceding claims, in which a rail extends above the table.

4. Hydroponic equipment as claimed in Claim 3, in which the rail extends longitudinally of the table centrally thereof.

5. Hydroponic equipment as claimed in Claim 4, in which a horticultural light is mounted on the table.

6. Hydroponic equipment as claimed in Claim 5, in which the horticultural light is movable along the rail by means of a light mover.

7. Hydroponic equipment as claimed in Claim 3, in which the table is provided at its corners with fittings whereby it can be supported on legs of such lengths that it is supported at the required inclination to the horizontal.

8. Hydroponic equipment as claimed in Claim 7, in which upward extensions of the legs serve as brackets for supporting the ends of the rail.

9. Hydroponic equipment as claimed in Claim 8, in which the upward extensions of the legs serve as structural members for forming an enclosure around the area in which the plants are located.

10. Hydroponic equipment as claimed in Claim 1, in which the table is formed of rigid fibreglass.

11. Hydroponic equipment as claimed in Claim 1 or Claim 10, in which the table has inclined side walls and a peripheral reinforcing flange.

12. Hydroponic equipment as claimed in Claim 11, in which the weir extends for the full width of the table.

13. Hydroponic equipment as claimed in Claim 12, in which means are provided whereby the nutrient solution is fed into a channel between the weir and the adjacent end proper of the table.

14. Hydroponic equipment as claimed in Claim 13, in which the drainage outlet through which the nutrient solution is discharged is arranged so that the nutrient solution can flow continuously into a reservoir from which the nutrient solution is withdrawn by a pump for return to the table.

15. Hydroponic equipment as claimed in Claim 13, in which the drainage outlet through which the nutrient solution is discharged is provided with a control valve.

16. Hydroponic equipment as claimed in Claim 13, in which the drainage outlet is provided with an outlet pipe through which the nutrient solution is discharged under a siphonic action.

17. Hydroponic equipment substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

18. A method of cultivation which includes the use of hydroponic equipment as claimed in any one of the preceding claims.