CH644490A5 - APPARATUS FOR HYDROPONIC CULTIVATION OF PLANTS. - Google Patents

Description

The invention relates to the cultivation of plants of all types and varieties, practiced according to the method of hydroponics.

There are three main modes of landless cultivation.

A first mode is constituted by the gravel culture, according to which gravel or a mixture of sand and gravel is kept inside walls on a firm base or inside a packed pocket. Irrigation is achieved by sending a stream of water that may contain nutrients into the gravel, or by spraying the surface of the gravel with nutrients. Ver-miculine or perlite, or another substrate can also be used instead of gravel.

The irrigation liquid is used at the frequency required by plant growth and the climate, this liquid is either returned to a tank by means of a pump, or evacuated by drainage on a device with total loss.

This landless cultivation method is described in articles and works by Sholto Douglas (India and the United Kingdom) and has no similarity with the present invention.

A second mode is constituted by the technique of the nutritive film, according to which a young plant or a plant is transferred in a thin plastic channel, whose upper edges are folded so as to retain the stem of the plant by means of pliers. A liquid containing nutrients is recycled in and around the channels, through thin conduits whose diameters are related to the pressure regime of the pump regulating the flow of the liquid in its channels. The maximum depth of the liquid in the channel is 1 mm. Dr. Alain Cooper (United Kingdom) has published books and articles on this subject. This technique is described in English Patent No. 1245581, the title of which is "Cultiva-tion of Plants".

The third mode involves deep water culture in recycling arrangements with a liquid depth greater than 1 mm. In this technique, the plants are transferred to a channel where germination takes place. A method of germinating seedlings for retention in the canal has been the subject of a complete English description by the inventor. Other previous work is that done by P. Van Lune and B.J. Van Goor, at the Institute for Soil Fertility in Haren, The Netherlands.

US Patent No. 3,925,926 describes a germination device of this kind which does not, however, include continuous circulation of the nutrient solution through the tank.

In another device described in US Pat. No. 3,660,933, the germination of the seeds is carried out separately, then the shoots having reached a given size are transferred into containers placed on the feeding tubs.

French Patent No. 2341263 describes a device in which the shoots are planted in cube-shaped containers, and these containers are placed inside channels of triangular section.

Still according to another US Patent No. 2,062,755, a multitude of shoots are arranged in elongated seedlings without being held in individual supports.

The object of the present invention is to remedy these drawbacks and to create an apparatus for hydroponics capable of being used on an industrial and commercially viable scale, comprising complete aeration of the nutritive fluid and continuous homogenization of the nutritive agents in the fluid without having recourse to auxiliary equipment. The apparatus according to the invention is characterized, for this purpose, in that it comprises a tank, means for continuously circulating a fluid through this tank, means for aerating the fluid during its circulation, means for adjusting the level of the fluid at the bottom and several removable supports for the plants, these supports for plants being capable of being fixed above the adjusted level of the fluid, the tank and the supports for plants forming a substantially closed device.

The appended drawing represents, by way of example, an embodiment and variants of the apparatus which is the subject of the invention.

Fig. 1 schematically represents the entire apparatus.

Fig. 2 is a perspective view of a plant support, the support housing being in two parts.

Fig. 3 illustrates schematically and in section the support for plants mounted in two different positions on the tank.

Fig. 4 illustrates in section the mounting of a cover on a support for plants.

Fig. 5 is a perspective view showing two supports connected by a cover.

Figs. 6 to 8 are perspective views of three variants.

Figs. 9 to 11 represent two variants in longitudinal and transverse section.

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644,490

The apparatus shown in fig. 1 comprises a gravity feed device 1 comprising a closed tank. The nutritive liquid is brought by a pump 2 from a tank 15 through a pipe 2a into the supply device 1. One or more outlet pipes 3 are provided with a valve 3a and conduct the liquid coming from the device d feed 1 by gravity to one or more tubs in the form of a channel 4. Another outlet 5 serves as an overflow and makes it possible to recirculate the excess liquid supplied by the pump to the device 1 by returning it by gravity to the tank 15. The pump 2 is adjusted so as to provide a greater flow rate than that required for the supply of liquid to the tank (s) 4. The valves 3a can be replaced by any other means of adjusting the flow rate.

The purpose of the gravity feed device 1 is to allow a constant column of liquid above the valves 3a thus ensuring a regulated flow of the liquid towards the tanks 4. The liquid discharged by the overflow falls in cascade towards the tank 15. During this spill and during the fall, there is aeration of the liquid. In addition, the nutritious chemicals contained in the liquid are completely remixed during these falls in cascades, so that the risks of an imbalance of the nutritive force of the liquid circulating in the tank 4 are considerably reduced.

The apparatus further comprises an inlet deflector 6,

against which the liquid from the valve 3a is sprayed into the tank 4, creating additional ventilation and homogenization of the nutrients. By tilting the deflector 6 at a determined angle, the liquid is projected towards the rear of the tank 4 and against the terminal cap of the latter, so that the spraying effect produced results in the formation of a film moving rapidly on the surface of the liquid in the tank 4. Because of the differences in flow, this newly aerated film is drawn towards the lower layers of the liquid in the tank 4. The stagnant areas around the roots of the plants are thus eliminated and the used liquid is brought in the direction of the outlet of the tank 4.

This outlet is provided with a level adjustment conduit 7 providing, by means of one or more holes 8, a means allowing the excess liquid in the tank to return via pipes 7a to the tank 15. Instead of having holes 8, the conduit 7 can be shortened so as to allow a discharge into the top of this conduit. The duct 7 is connected to the tank 4 by means of a seal 14 and is capable of being moved vertically relative to this seal. It is thus possible to adjust the level of liquid in the tank 4.

By completely removing the conduit 7 from the seal 14, the tank 4 can be emptied of the liquid for cleaning, the plants remaining in place. Narrow slots 9 can be cut in the adjustment duct 7 below the hole 8, in order to allow a flow of the lower levels of the liquid in the tank 4 at a lower flow rate than that at the inlet 3 and at the outlet main 8. These slots can be arranged in any convenient manner and be made in any size and in any number considered appropriate.

The dimension of the adjustment duct 7 is such that an additional cascade flow and a homogenization of the nutritive medium occur during the exit of the liquid coming from the tank 4 and during its fall on the surface of the liquid contained in the tank 15 .

The plants 30 are retained in removable supports 10 capable of being fixed to the walls of the tank 4. Lids 16 connect the supports 10 and protect the interior of the tank 4 against the introduction of foreign bodies, while reducing evaporation liquid in hot climate.

With reference to fig. 2 to 4, the plant supports 10 comprise lateral fixing projections in the form of rails 10a intended to cooperate with the upper edges of the tank 4. These rails 10a are connected to the support 10 in an off-center position and have a shape such that the support 10 can be returned. In this way, it is possible to adjust the distance separating the support center 10 from the bottom of the tank 4.

In addition, these plant supports 10 have a removable internal part 12 allowing easy installation and removal of plants.

These can be surrounded by individual protection elements or envelopes, not shown. In order to prevent any involuntary separation, the internal part 12 is retained in the support 10 by bolt or any other suitable fixing means.

The side rail 10a of the support 10 has an opening directed upwards, intended to receive fastening parts 13 making it possible to retain the cover 16 connecting the support 10 to the adjacent support. This cover 16 is constituted by flexible plastic capable of deforming by forming folds of the accordion type 25. These folds allow the supports for plants to move relative to each other, in order to adjust the space which separates them. depending on the size of the plants.

At the inlet and / or outlet ends of the tank 4, when a plant support does not constitute a closure of the upper part of the channel, the cover 16 can be fixed to the inner faces of the inlet and outlet ends of the tray 4, to ensure the closure of the upper surface.

With reference to fig. 6 and 7, the tank can be constituted by a closed conduit of circular 17 or rectangular section 19. Other sections 18, 20 can be envisaged (FIGS. 8 and 5).

When cuts 21 are made in a conduit or a tube, the distance between the supports for plants will be determined by the spacing of these cuts. It is also possible to provide an upper cover 22 (FIG. 8) ensuring the protection of the tank 4, the distance between the plant supports being determined by the length of this cover 22. The variation in the distances between the plant supports will then be determined by changing the length of the covers 22.

With reference to fig. 9 to 11, it is possible to install a tray 23 on an oblique surface. The plant supports 10 then comprise a tongue 24 projecting from the underside of the support 10. This tongue 24 can be permanently fixed or inserted between the two separable parts of the support 10, so as to allow its movement on the opposite face when the support 10 is returned. These tongues 24 form weirs which only partially close the tank, so as to allow the liquid present in the latter to flow above the upper face of the weir at the location or in the vicinity of the roots of the plant.

This provides additional ventilation, while ensuring the roots of each plant a depth of liquid and a supply of nutrients. Another advantage is to avoid drowning the plant or having excessive flow from the orifices of the plant supports at the lower locations of the tank.

By admitting liquid from the valve 3 at the inlet of the tank, the liquid circulates from one overflow to the other and finally towards the outlet conduit. The tongue 24 constituting the weir can be full or perforated and does not necessarily have to form a tight fit in the tank 4.

In some cases, for example for the cultivation of edible roots or bulbs, the weir or an appropriate gauze, provided in the plant support or in any location along the tank linked or not to the weir, will act as a barrier intended to retain a substrate inside which the edible root or bulb develops.

The aeration and homogenization of the nutrients are not affected by the intermittent flow caused by the opening and closing of the valve 3 at appropriate intervals, insofar as the pumping of the liquid to the supply device 1 by gravity can be continued with the valve open or closed as part of a reduced cycle of operations, without affecting the operation of the installation.

The demand for facilities designed for the landless cultivation of plants, especially plants for food, is increasing

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in proportion to the development of the world's population. This demand is very important in developing countries where climatic or soil conditions are not suitable for current horticultural or agricultural methods.

In addition, it is necessary to conserve water resources, energy, as well as mineral or organic chemicals used for plant nutrition.

These factors direct demand towards commercially profitable techniques for landless crops that have not been developed in the past.

The measures taken to obtain complete aeration have only been considered essential in recent years 5 for plant development. Likewise, the continuous homogenization of nutrients in a hydroponic system is now considered essential. None of these measures could have been carried out beforehand without the use of auxiliary equipment.

2 sheets of drawings

Claims (9)

644,490 1. Apparatus for hydroponics of plants, characterized in that it comprises a tank, means for continuously circulating a fluid through this tank, means for aerating the fluid during its circulation, means for adjusting the level of the fluid in the tank and several removable supports for the plants, these supports for plants being capable of being fixed above the regulated level of the fluid, the tank and the supports for plants forming a substantially closed device. 2. Apparatus according to claim 1, characterized in that the support for plants comprises a housing capable of being separated in two in order to be able to introduce or remove plants, the plants being capable of being arranged in individual support elements, the housing being shaped so as to be mounted on the side walls of the tank. 2 3. Apparatus according to one of claims 1 or 2, characterized in that the tray is an open tray, along which are placed supports for plants, and in that there is provided between the supports for plants protective covers of the accordion type closing the tank. 4. Apparatus according to one of claims 1 to 3, characterized in that the tank consists of a tube or a closed conduit, of circular or rectangular section, having cut portions adapted to receive the supports for plants. 5. Apparatus according to one of claims 1 to 4, characterized in that the supply of fluid to the tank is effected by means of a reservoir mounted above the level of the tank, supplied with the fluid coming from 'A tank by means of a pump, the reservoir having an outlet duct to the tank comprising means for adjusting the flow rate of the fluid and an outlet-weir with a duct for returning the fluid to the tank. 6. Apparatus according to claim 5, characterized in that the outlet conduit from the reservoir to the tank is arranged so as to direct the fluid against a deflector mounted inclined relative to the direction of the fluid, so as to obtain aeration of the fluid and to form a surface film moving rapidly along the surface of the fluid inside the tank. 7. Apparatus according to one of claims 1 to 6, characterized in that the level of the fluid in the tank is adjusted by means of a vertical pipe mounted sliding and sealed in an outlet orifice at the base of the tank, this pipe having one or more holes or slots along its length through which the fluid coming from the tank can flow, said level being determined by the height to which the duct is adjusted. 8. Apparatus according to claim 1, characterized in that the fluid aeration means comprise a series of deflectors arranged at one or more points in the path of the circulation fluid. 9. Apparatus according to claim 8, characterized in that at least some of the deflectors are placed on the flow path of the fluid, so as to act as a weir around which and / or above which the fluid spills when 'it circulates.