WO1993019584A1

WO1993019584A1 - Apparatus for sterilizing growing material

Info

Publication number: WO1993019584A1
Application number: PCT/NL1993/000075
Authority: WO
Inventors: Hendrik Leonardus Koenen
Original assignee: GROWING SYSTEMS BV
Current assignee: GROWING SYSTEMS BV
Priority date: 1992-03-30
Filing date: 1993-03-26
Publication date: 1993-10-14
Anticipated expiration: 1994-09-30
Also published as: NL9200587A; AU3908393A

Abstract

The invention relates to a holder (1, 8) for culture material (2, 11) wherein means (4, 7, 9, 12) are present for feeding to a culture material (2, 11) a gaseous medium having a cleaning or temperature changing function. Due particularly to the cleaning function of the gaseous medium, for instance steam, it is possible to clean the culture material (2, 11) in situ. It is therefore not necessary to remove the culture material (2, 11) from the holder (1, 8) for cleaning thereof.

Description

APPARATUS FOR STERILIZING GROWING MATERIAL

The invention relates to a holder for culture material. Such holders are generally known.

They are used for cultivating diverse crops. By culture material can be understood any porous medium that is suitable for cultivating crops, such as peat dust, synthetic fibre mats, mineral wool and mixtures of the above materials with each other and with other materials, for instance sand.

After a crop has been cultivated and the flowers and/or fruits of the crop have been harvested, it is important that the culture material is cleaned. The culture material is in any case usually made of non-biodegradable materials so that it cannot be processed well as waste. The purchase of new culture material is moreover expensive.

A device is known from the Netherlands patent application 8503027 for cleaning such material.

In this known device the culture material is removed from the holders and placed in a separate sterilization area arranged in a truck. The culture material is then sterilized by a sterilizing medium, for instance steam. Removal of the culture material from the culture trays and placing of this material in the sterilization chamber is a very labour-intensive process; it is moreover only feasible in the case of culture materials having a mutually cohesive form such as mats of synthetic fibres, mineral wool and the like; with peat dust such a process can only be carried out with exceptional difficulty because this loose material must be shovelled out of the trays and taken to the sterilization area.

The present invention endeavours to provide a device and a H-athod with which the above stated problems are obviated.

This object is achieved by means for feeding a gaseous meaning medium to the culture material.

As a result of these steps it is possible to sterilize the culture material while it is in the culture trays, which avoids the work of carrying the culture material into the sterilization chamber and, once sterilized, taking thereof from the sterilization chamber back to the culture trays.

In the trays for culture material channels are in a large number of cases already present for draining excess water, so that it is attractive to make use of these already present channels for draining excess water for feed of the cleaning medium.

It is of course necessary for the drain channels to be adapted for this purpose. The present invention will now be elucidated with reference to the annexed figures, in which: fig. 1 shows a partly broken away perspective view of a first embodiment of a holder according to the invention; fig. 2 shows a partly broken away perspective view of a second embodiment of a holder according to the invention; fig. 3 is a partly broken away perspective view of a third embodiment of a holder according to the invention; fig. 4 shows a partly broken away perspective view of a fourth embodiment of a holder according to the invention; fig. 5 is a sectional view of a fifth embodiment of a holder according to the invention; and fig. 6 is a partly schematic view of a device according to the invention.

The holder depicted in fig. 1 is formed by a double-walled tray 1 in which is arranged a quantity of culture material 2. This culture material may be formed by peat dust, soil, mineral wool, synthetic fibre mats, mixtures thereof or mixtures thereof with sand or another filler material.

Due to the double-walled form an enclosed channel 3 is created which is normally used for draining the excess water supplied to the culture material 2 for instance by a sprayer system.

Arranged in the internal bottom 4 of tray 1 in the vicinity of the side walls is a stepped elevation 5, wherein this elevation is joined to the actual internal bottom 4 by means of walls 6 extending substantially vertically. These walls 6 do not necessarily have to extend vertically, however, they may also be inclining, although it is important that they form a connection between two different horizontal levels, wherein they thus possess a vertical component. A series of slot-like openings 7 is arranged in the walls 6 which are used for draining excess water.

When the culture material arranged in this tray has to be cleaned, for instance sterilized, a gaseous cleaning medium is fed to the channel 3 by means of a device to be discussed later. The embodiment shown in fig. 2 differs from the embodiment of fig. 1 in that the stepped elevation is omitted and in that openings 7 are arranged in the bottom.

In the embodiment shown in fig. 3 the openings 7 are arranged in the side walls 6. It is thus possible to choose an embodiment adapted to the culture material, crop or watering method in use. Shown in fig. 4 is the other embodiment, wherein a pipe 9 bent in a zigzag is arranged in a tray 8. The pipe 9 is arranged on the bottom of the tray. Holes 10 are arranged in the top and in the upper part of the sides of pipe 9. Drainage of the culture material 11 present in tray 8 takes place via holes 10 and, when the tray has to be sterilized, steam can be supplied by means of the pipe 9, wherein the steam passes through the holes 10.

Due to the distribution of the holes, a good distribution of the steam in the culture material 11 is obtained. For feeding steam or draining of drainage water the pipe is coupled to a connection stump.

In the embodiment shown in fig. 5 a separate bottom 13 is arranged in a tray 12. In this embodiment the bottom 13 has a zigzag-shaped section. To prevent sagging of the tray when the tray has a large width and is filled with a culture material with a high density, the bottom 13 is provided with supports 14.

As a result of these steps this embodiment is also suitable for cultivating larger plants and cut flowers, for instance chrysanthemums 15. At both sides the bottom plate 13 is folded over so that a portion of double thickness is obtained, and the plate is then folded downward so that a support 16 is also obtained in the vicinity of the sides. Supports 16 and the double-folded portion 17 of the plate enclose a channel 18. Perforations 19 are arranged in the deepest portions of the zigzag folded plate 13, perforations 20 are also arranged in the supports 14 situated in the middle and perforations 21 are arranged in the substantially horizontally extending parts 16.

The space under plate 13 is used for draining excess water. From the openings 19 this excess water enters the relevant channels, wherein due to the openings 14 between the channels a good distribution of the excess water is obtained.

For supplying steam use is made of the channels 18; the steam fed via channels 18 passes through openings 21 into the spaces under plate 13, wherein a good distribution is ensured by the openings 14. The steam passes through the openings 19 into the culture material, wherein the latter is cleaned.

Finally, fig. 6 shows how by means of a schematically shown steam boiler 22 and a conduit system 23 steam can be supplied to a connection stump 24 arranged on the trays. Also shown here is how the trays 1 are connected in series and how the groups of trays connected in series are connected in parallel. It will be apparent that the layout shown here only relates to a layout for supplying steam; each tray is provided with a separate discharge for draining excess drainage water. Although the above mentioned embodiments relate to sterilization by means of steam, it will be apparent that other gaseous sterilization means can also be applied for feeding the cleaning medium.

It will of course be necessary for the drain channels to be adapted for this purpose.

In the embodiments according to fig. 1, 2, 3, 5 and 6 the configuration of the drain channel by means of the so-called false bottom prevents drainage water, once it has entered the channel, from coming into contact with the roots of the plants. These steps prevent the danger of infection as a result of diseased plants. In the embodiment shown in fig. 6 a completely closed system results which can also be used for draining excess drainage water; environmental pollution by fertilizers is hereby prevented and re¬ use of the fertilizers becomes possible. Application of the so-called ebb and flow system for draining and feeding water from and to culture material is also possible in combination with the present invention, particularly with the embodiments according to fig. 1, 2, 3, 5 and 6.

Finally, it is possible to use the channels for temperature control of the culture material. It is for instance possible to cool or heat the culture material. Heating of the culture material in particular results in a considerable energy-saving, because in many crops growth is stimulated by holding the roots at quite a high temperature. By heating only the culture material to this temperature, which is possible with the device according to the invention, it becomes possible to hold only the culture material at such a temperature and to heat the greenhouse to a lower tempera¬ ture.

Claims

1. Holder for culture material, characterized by means for feeding a gaseous medium to the culture material.

2. Holder as claimed in claim 1, characterized in that the means are suitable for feeding a medium which cleans the culture material.

3. Holder as claimed in claim 1 or 2, characterized in that the means are suitable for feeding a medium which heats or cools the culture material.

4. Holder as claimed in claim 1, 2 or 3, provided with means for draining excess water, characterized in that the means for draining excess water are combined with the means for feeding the gaseous medium.

5. Holder as claimed in claim 1, 2, 3 or 4, characterized in that the gaseous medium is steam.

6. Holder as claimed in any of the claims 1-5, characterized in that the draining means are formed by at least one channel with rigid walls.

7. Holder as claimed in claim 6, characterized in that the holder is formed by a tray, wherein channels are arranged connecting to the bottom of the tray for draining excess water and for feeding the cleaning medium.

8. Holder as claimed in claim 7, characterized in that the channels are arranged above the bottom of the tray and that they are provided with openings at least on their top part.

9. Holder as claimed in claim 7, characterized in that under the bottom of the tray is arranged a channel whereof the width substantially corresponds with the width of the tray and that in the bottom is arranged at least one stepped elevation, wherein openings are arranged in a vertical wall between the stepped elevation and the bottom.

10. Holder as claimed in claim 7, characterized in that under the bottom of the tray is arranged a channel which also extends on the sides of the tray, wherein openings are arranged in the side walls of the tray.

11. Holder as claimed in claim 7, characterized in that the underside of the openings are located above the upper part of the bottom.

12. Device for sterilizing culture material arranged in holders, characterized by a steam generating device and a conduit system forming a connection between the steam generating device and the holders for culture material.

13. Device as claimed in claim 12, characterized in that the conduit network is at least partially removable.

14. Device as claimed in claim 12 or 13, characterized in that the holder as claimed in any of the claims 1-10 is connected in series at least in groups and that the groups of trays connected in series are connected in parallel.

15. Device as claimed in claim 12, 13 or 14, characterized in that the conduit network forms a closed system.