Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND ARRANGEMENT FOR GROWING PLANTS
Technical field
The present invention relates to a method and arrangement
for growing plants in a vertical greenhouse. More
specifically the present invention relates to a method and
an arrangement for growing plants in an industrial manner in
a vertical greenhouse.
Description of the prior art
A problem in urbanized areas is that food, once grown and
harvested in farms in other regions and countries must
travel long distances to reach the consumers in the cities.
Such food transports consume energy and adds to the traffic
congestion in the cities. A further problem is that
greenhouses are often situated far outside urban areas and
urban customer's food budget therefore goes to pay for
transportation as well as storage.
Hence, growing food crops in vertical greenhouses in cities
would help reduce both environmental pollution caused by
transportation and transportation costs since the plants are
grown where the consumers are. Moreover, vertical
greenhouses would be space-efficient and would be adapted
for expanding cities where there is a shortage of space.
Additionally, vertical greenhouses would be built close to
the customers; consequently, the produce would be delivered
fresh and at a lower price.
The U53432965 patent document discloses a hydroponics
apparatus for automatic germination of seed, growth of
produce therefrom and harvesting of produce. A major
disadvantage with this apparatus is that it is not adapted
for industrial scale production of plants and crops in urban
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areas since the surface area for the crops to grow is highly
limited, as indicated in the specific examples. Moreover,
the examples, as well as the claims, clearly illustrate that
a plurality of containers holding seeds are connected to a
pair of parallel and spaced apart members and that the
containers are conveyed horizontally along these members.
However, a major disadvantage with this system is that the
distance between the parallel members is limited, and this
system is therefore not adapted for tall plants. Hence, this
system is not applicable for growing all sizes of plants and
crops. Additionally, the horizontal conveying system is
inflexible and does provide means for long distance
transport of plants vertically and diagonally, which makes
this system vulnerable in case of malfunction of the
horizontal conveying system. Furthermore, the hydroponics
apparatus is not modifiable to be integrated with space-
efficient vertical greenhouses since the hydroponics
apparatus employs a horizontal means of conveying
containers. Interestingly, it is not even suggested that the
hydroponics apparatus can be integrated or connected with
any type of greenhouse. Another disadvantage is that the
seeds are not sown in pots, which makes this system
inflexible since seeds which have not germinated cannot be
removed efficiently. Yet a further disadvantage is that pots
are not sterilised after harvest together with the growing
medium; hence a method of decreasing waste is not indicated
in US3432965.
The patent application W02010/138027 describes a conveying
system and a method for conveying containers. The system and
method is primarily intended for moving containers with
plants in greenhouses for cultivating plants. However, this
document does not (i) disclose any specific methods and
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arrangements for cultivating plants, (ii) indicate a
cultivation system wherein pots are sterilised after harvest
together with the growing medium in order to decrease waste,
and (iii) describe the use of pumice for growing plants.
Furthermore, the greenhouse described in W02010/138027 does
not comprise a sowing device, a germination device, a device
for movement of pots into and/or out of trays, an elevator
which moves trays with pots with germinated seeds to the
starting position of the top of the track, a sterilisation
device, and an optional biogas production facility. More
importantly, the transport of trays is inflexible since it
is dependent on the conveying device, and any other means of
transporting the trays along and/or between the tracks has
not been disclosed.
The patent application US 2009/0307973 Al describes a
vertically-integrated greenhouse which provides a system of
food production in buildings and which can be installed in a
double-skin facade. The trays with plants are arranged and
affixed to a tray suspension system to which the trays are
adjustably affixed one above another in parallel vertical
rows and can be vertically raised or lowered. However, a
major disadvantage with this system is that the distance
between the trays has to be increased as the plants grow
which limits the number of trays in circulation. Hence, this
system is not adapted for industrial growth of plants and
crops.
Summary of the invention
An important objective of the present invention is to
provide a flexible and automated method and arrangement for
cultivating all sizes of plants, as well as to provide a
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higher surface area for the crops to grow in, and thereby
provide means for industrial scale production of crops.
An objective of the present invention is to provide a method
and an arrangement for an energy efficient method of growing
plants.
A further objective of the present invention is to provide a
method and an arrangement for industrial growth of plants
which requires a minimum of space and energy.
At least one of these objectives is provided with a method
and an arrangement according to the independent claim.
Additional advantages are provided with the features of the
dependent claims.
A method according to the invention for cultivating plants
comprises the steps of sowing seeds in the growing medium in
sterilised pots using a sowing device and allowing the seeds
to germinate in a germination device. The pots are
automatically moved through a greenhouse to allow the
germinated seeds to grow into plants, which are then
harvested using a harvester. After harvest the pots are
sterilised together with the growing medium in a
sterilisation device in order to provide sterilised pots
with a growing medium. The method provides for efficient
growth of plants and may be performed with a minimum of
human intervention. By not exchanging the growing medium,
but instead sterilising the pot with the growing medium the
waste from the method is drastically decreased in comparison
with traditional methods.
Any growing medium that has been lost during harvest may be
refilled before sowing.
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The growing medium may be any growing medium that is
suitable for re-use after sterilisation without being
removed from the pot. The growing medium is preferable
pumice, which surprisingly has shown to be very suitable to
5 use in a method according to the invention.
The size of the pumice effects its suitability for growth of
plants. A suitable particle size of the pumice for growing
vegetables such as Brassica rapa var. chinensis, Brassica
rapa spp. Nipposinica, Chrysanthemum coronarium and many
other vegetables is 0,5-3 mm. Such pumice is sold as Hekla
green. A major part of the pumice preferably has a particle
size of 0,5-3 mm.
The pots may have an essentially quadratic shape viewed from
above. This is an advantageous shape to handle for automatic
devices that are to handle the pots.
The height, width and length of the pots may be in the
interval 0,03-0,3 metres, preferably 0,05-0,2 metres and
most preferred in the interval 0,07-0,12 metres. With such
dimensions a sufficient amount of growing medium may be
contained in the pot for the above mentioned plants to grow.
It is favourable not to exceed the mentioned dimensions as
this will add to the mass that has to be transported in the
system and will thus add to the energy consumption of the
method. Furthermore, it is advantageous not to increase the
height of the pots also for the reason that the watering of
the plants may be more difficult if the pots are made too
high. If the pots are made too high it is not possible to
let them absorb water from below.
The pots may have at least two opposite walls that are
slightly inclining so that the cross-sectional area of the
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pots decreases towards the bottom of the pots. This will
make it easier to remove the pots from a support.
The pots with germinated seeds are preferably placed in
trays. In this way a large number of pots may be controlled
in a more simple way. With the pots being placed in trays it
is preferable to have the above mentioned inclining walls as
this facilitates the removal of the pots from the trays.
The pots may be removed from the trays before germination
but after sterilisation so that the trays are sterilised at
the same time as the pots. By removing the pots from the
trays the pots may be placed in contact with each other
during sowing and germination. This saves space and thus
decreases the size and cost of the devices for handling the
pots during sowing and germination. During sowing and
germination the plants do not extend outside the pot. During
growth the plants may grow to extend outside the pot making
it necessary to arrange the pots at a distance from each
other.
The trays may have a decreasing width towards the bottom,
which corresponds to the width of the pots. By having
corresponding shapes of the pots and the trays the pots may
be well supported in the trays.
The trays may be elongated with a length axis to allow a
single row of pots to be placed in the tray along the length
axis. By having only a single row of pots arranged in the
trays the distance between the pots may be varied in one
dimension during growth of the plants. This makes it
possible to adapt the size between the pots as a function of
the size of the plants during the growth. This makes it
possible to use the space in the greenhouse more
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efficiently. Alternatively it is of course possible to have
trays which allow more than one row of pots.
The method may also comprise the step of, before placing the
pots in the trays, controlling that the seeds in the pots
have germinated so that only pots in which the seeds have
germinated are placed in the trays. This is important in
order to optimize the output of the method. In this way no
pots without plants will be transported through the
greenhouse.
The method may comprise the step of using a greenhouse with
a track comprising at least two essentially parallel beams
for supporting the trays, which track has a form resembling
a helix, on which track the trays are arranged to be moved
so that they are exposed to sunlight. By using such a
greenhouse an efficient use of the ground is provided, which
is advantageous if the method is to be used in a city.
The method may comprise the use of a greenhouse in which the
trays on the tracks are to be arranged with their length
axes perpendicular to the beams of the tracks. This is
advantageous in that the distance between the pots in one
direction may easily be adapted to the size of the plants.
The method may also include the step of intermittently
watering the plants by intermittently providing water to the
trays, wherein the pots and the trays are arranged for the
growing medium in the pots to absorb water in the trays.
This is an uncomplicated way of watering the plants as the
growing media in the pots absorb the necessary amount of
water.
The method may comprise the step of providing the trays with
a bottom that is inclined at an angle of 0,5-2 degrees to
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the horizontal direction. By providing the trays with an
inclining bottom the water will stream along the tray. In
this way water will be provided to all pots in the tray.
With an inclining bottom it is also avoided that water forms
static puddles in which germs and bacteria may grow.
The sterilisation may be performed by heating of the pots
with the growing medium. By performing the sterilisation by
heating the use of chemicals is avoided which may be
advantageous.
The heating may be performed using steam. The use of steam
is an uncomplicated way of sterilising the growing media,
the pot and the tray.
Alternatively the heating may be performed using microwave
radiation to heat the residual water in the pots, to thereby
heat the growing medium and the pots. This is a fast and
efficient way of heating the growing medium.
The time period during which the pots are heated may be
chosen so that the majority of the bacteria is killed.
According to a second aspect of the present invention an
arrangement for cultivating plants is provided, which
apparatus comprises
a sowing device for sowing seeds in a growing medium
arranged in pots,
a germination device for allowing the seeds to
germinate in the pots,
a greenhouse for allowing the germinated seeds to grow
to plants,
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means for moving the pots through the greenhouse,
a harvester for harvesting the grown plants, and
a sterilisation device for sterilising the pots with
the growing medium after harvest in order to provide
sterilised pots with a growing medium.
The arrangement according to the second aspect of the
invention provides for efficient growth of plants and may be
performed with a minimum of human intervention. By not
exchanging the growing medium, but instead sterilising the
pot with the growing medium the waste from the method is
drastically decreased in comparison with traditional
methods.
The arrangement may comprising an arrangement device (i.e. a
device for movement of pots) for arrangement of the pots in
trays with a length axis. By arranging the pots in trays it
is possible to minimize the size of the pots, and thus also
the weight of the growing medium, while maintaining a stable
arrangement of the pots during growth.
The trays may have a decreasing width towards the bottom,
which corresponds to the width of the pots. By having the
pots and the trays arranged in this way the pots are well
supported by the trays and will also be relatively easily
removable due to the decreasing width of the pots. Pinching
of the pots in the trays is avoided due to the decreasing
width of the pot.
The trays may be elongated to allow a single row of pots to
be placed in the tray along the length axis. With such trays
the distance between the trays and thus also the pots may be
varied.
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The means for moving may comprise a track comprising at
least two essentially parallel beams for supporting the
trays, which track may have a form resembling a helix, and
at least one conveying device which is arranged to travel
5 along the track and which comprises a tray moving unit,
which after passing plant tray is arranged to move at least
one tray one step along the track, the conveying device thus
moving containers stepwise along the track during the travel
along the track. Such means for moving requires a limited
10 power as only a small number of trays are moved simul-
taneously. Alternatively the means for moving may comprise
standard conveyor belts which are arranged to move the
trays.
Alternatively the track may be divided in a number of track
portions connected by track connection means, such as, e.g.,
an elevator. The track portions may be horizontal.
The tracks may be arranged for arrangement of the trays on
the tracks with their length axes perpendicular to the beams
of the tracks. By arrangement of the trays in this way the
distance between the pots may be easily variable in one
direction.
The track may be arranged inclined at an angle of 0,5-2
degrees to the horizontal direction, which hinders water
from remaining on the bottom of the trays. Thus, the pots
may be provided with water by providing the trays with water
at the high end. The water will then flow down the tray and
pass the pots. The growing medium in the pots will absorb
water, and the remaining water may flow out of the tray
through an opening provided at the lower end of the tray.
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The arrangement may comprise watering means arranged for
intermittently providing water to the trays at the highest
side of the trays. By intermittently providing water to the
trays the watering may be performed more economically.
The watering means may comprise pipes situated at distances
corresponding to the length of the steps of the stepwise
movement of the trays. Thus, the trays are moved to
positions corresponding to the positions of the pipes.
The arrangement may further comprise a system for
continuously purifying excess water that flows out from the
openings in the trays. The excess water may pass through a
mechanical filter for separating plant parts and pumice from
the water. A biological filter comprising zeolite and pumice
may be used to purify the water from pathogens and
metabolites. A second mechanical filter may be used to
separate zeolite and pumice particles from the water
purified by the biological filter. A UV filter may also be
employed if necessary. The excess water which has passed
through the various filters can be collected in buffer
tanks. The recycled excess water may be mixed with nutrient,
fertilizer and fresh water, and then pumped back to the
relevant parts of the arrangement.
The arrangement may be integrated or connected with a biogas
production plant, so that organic waste from the harvest is
transported to the biogas production plant and bionutrients
from the biogas production is transported to the means for
sowing seeds in pots. Such an integration of a biogas
production plant gives mutual advantages by providing a way
of dispensing the waste products from one process to the
benefit of the other process.
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The arrangement may also comprise means for inspection that
the seeds in the pots have germinated. Such means may be
comprised of a camera connected to a computer. By providing
such means pots in which the seeds have not germinated may
be returned to the sowing device. In this way the efficiency
of the arrangement may be optimised.
The trays may comprise a unique identification tag such as
Radio Frequency Identification (RFID) tag or barcode, and
scanning devices can be placed in various parts of the
arrangement. Hence, the movement of the trays within a track
portion, as well as, between one track portion and another
track portion below, can be monitored and controlled.
Short description of the drawings
In the following preferred embodiments of the invention will
be described with reference to the appended drawings on
which:
Fig 1 shows schematically, partly in cross-section, a
building for industrial growth of plants.
Fig 2 shows in cross section the bottom of the building
shown in Fig 1.
Fig 3 shows partly in cross section a building for
industrial growth of plants according to an alternative
embodiment of the present invention.
Fig 4 shows schematically an arrangement for cultivating
plants according to an embodiment of the present invention.
Fig 5 is a flow diagram of a process for growing plants
according to an embodiment of the present invention.
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Fig 6 shows a tray and a robot for arranging and/or removing
pots from the tray.
Fig 7 shows schematically a germination device for
germination of seeds in the pots.
Fig 8 shows in cross section a tray with pots that is used
in a process for industrial growth of plants according to an
embodiment of the present invention.
Fig 9 is an exploded view of the tray and pots shown in Fig
8.
Fig 10 shows schematically a harvester used in the method
and arrangement of the invention.
Fig 11 shows in cross section the track for the arrangement
of trays with pots and plants according to an embodiment of
the present invention.
Fig 12 shows the track for the arrangement of trays with
pots and plants according to an alternative embodiment of
the present invention.
Description of preferred embodiments of the invention
In the following description of preferred embodiments the
same reference numerals will be used for similar features in
the different figures. It is to be noted that the figures
are not drawn to scale.
Fig 1 shows, partly in cross-section, an arrangement
according to an embodiment of the invention in the form of a
building 1 for industrial growth of plants. The main part of
the building is a greenhouse 2 in which two parallel tracks
3, 3', are arranged for supporting trays (Fig 3). The tracks
3, 3', have a form resembling a twinning helix, on which
tracks 3, 3', the trays (Fig 3) are arranged to be moved
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from the top of the building to the bottom of the building
so that the plants are exposed to sunlight. The tracks 3, 3'
can each comprise up to 4 parallel track portions (14). A
sowing device, a germination device, a harvester and a
sterilisation device (Fig 2) are arranged in the bottom of
the building 1. The building 1 also comprises an elevator 4
for moving trays from the bottom of the building to the
start of the track at the top of the building 1.
Fig 2 shows in cross section the bottom of the building
shown in Fig 1. In Fig 2 it is shown how the tracks enters
the bottom floor of the building 1. The trays are then
passed through the harvester 5, and the sterilisation device
6. The pots are then removed from the trays and passes the
sowing device 7, and the germination device 8 before the
pots are arranged in the trays and lifted up to the top of
the building by means of the elevator 4.
Fig 3 shows partly in cross section a building 1 for
industrial growth of plants according to an alternative
embodiment of the present invention. In the embodiment shown
in Fig 3 the greenhouse comprises a track 3 with a number of
track portions 14 with a length axis 15 for the arrangement
of trays 9. The track portions are connected with track
connecting means 18, which each have a length axis 19 and
which connect the track portions 14. The trays 9 are
elongated with a length axis 16 and arranged for placement
of pots 17 in a single row along the length axis 16 of the
tray. Growing medium in which plants are to grow is arranged
in the pots 17. The track portions 14 are arranged for trays
9 to be arranged with their length axes 16 perpendicular to
the length axes 15 of the track portions 14. In the shown
embodiment the track connecting means comprises inclining
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straight paths 18 with length axes 19, wherein the paths 18
are arranged for transportation of trays 9 with their length
axes 16 parallel to their direction of transportation. The
straight paths 18 are arranged for the trays to slide down
5 (diagonally) from one track portion 14 to another track
portion 14 below. Furthermore, this embodiment also provides
flexible means for trays to bypass a hindrance or a stop in
the transportation route, e.g. caused by malfunction in the
vertical transportation route of the elevator, by providing
10 diagonal means of transport of trays in the greenhouse.
Watering means in the form of water outlets 10, of which
only three are shown, are provided to intermittently provide
water to the trays 9 on the track portions 14. The water
outlets 10 are arranged at a distance corresponding to the
15 intended pitch 12 between the trays 9. In this way each one
of the trays 9 may be provided with water at each time. The
time interval between the points of time when the trays 9
are provided with water is adapted to the vegetable in the
pots 17 of the tray 9.
The description of the placement of trays on the track is
valid also for the embodiment of Fig 1.
The greenhouses described above are preferred embodiments of
the greenhouse according to the invention. However,
according to the invention it is possible to use any other
type of greenhouse in which plants are automatically moved.
Fig 4 shows schematically an arrangement 1 for cultivating
plants according to an embodiment of the present invention.
Fig 5 is a flow diagram of a process for growing plants
according to an embodiment of the present invention. The
arrangement and the method will be described in the
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following.
The growing medium in the pots 17 may be any growing medium,
which is suitable for repeated cultivation of plants, so
that new seeds may be sowed in the pots after harvest
without having to exchange the growing medium. A suitable
growing medium is pumice. Pumice is available from many
different sources and may have different properties. A
suitable particle size of the pumice for growing vegetables
such as Brassica rapa var. chinensis, Brassica rapa spp.
Nipposinica, Chrysanthemum coronarium and many other
vegetables is 0,5-3 mm. Such pumice is sold as Hekla green.
The volume of the growing medium is suitably about 0,5-1
litres. Pots and trays are described in more detail below
with reference to Fig 8 and 9.
The pots with the growing medium are provided to the sowing
device 7, in which seeds are sowed in the growing medium in
the pots. This corresponds to step 32 in Fig 3. The sowing
device 7 may comprise a machine such as a robot that puts
the seeds into the growing medium and provides a suitable
amount of water to the growing medium. In the sowing device
7 the growing medium in the pots may also be provided with
nutrients and fertilizers to enhance the growing of the
plants.
Alternatively the sowing device is only partially automated.
The sowing of the seeds may be performed manually by a
person operating the sowing device. The sowing device may
then perform only parts of the sowing operation.
After the sowing the pots 17 are moved by a machine or
manually to a germination device 8, in which the sowed seeds
are allowed to germinate. This corresponds to step 33 in Fig
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3. In the germination device 8 the temperature and humidity
are optimised to enhance germination and the pots 17 may
also be provided with water at suitable intervals. The
temperature and humidity in the germination device 8 are
kept suitable for the specific seeds to germinate. The pots
17 are kept in the germination device 8 for a predetermined
time after which they are transported manually or
automatically to means for inspection 24.
In the means for inspection 24 the pots are inspected
manually or by an automated system utilising a digital
camera 23, to determine whether the seeds have germinated or
not. The pots 17 in which the seeds have not germinated are
sent back to the filling station 21 while the pots 17 in
which the seeds have germinated are sent to the arrangement
device 25 (i.e. the device for movement of pots).
In the arrangement device 25 (i.e. the device for movement
of pots) the pots are placed in a single row in elongated
trays 9. The pots 17 are placed in the trays 9 manually or
automatically. The trays 9 are then moved to the greenhouse
2.
In the greenhouse the trays are moved automatically along
the track 3, 3', in the greenhouse 2, as has been described
above, to allow the germinated seeds to grow into plants.
This corresponds to step 34 in Fig 3. The track in the
greenhouse extends from a starting position, which
preferably is situated at the top of the greenhouse, to an
end position, which preferably is situated at the bottom of
the greenhouse. By arranging the track inclining from the
starting position to the end position the gravity will help
moving the trays along the track. The track in the green-
house 2 is described in more detail in connection with Figs
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11 and 12. During movement through the greenhouse 2 the
pumice in the pots is provided with water by intermittently
providing water to the trays 9 in which the pots 17 are
arranged. The pots 17 are arranged to allow the pumice in
the pots 17 to absorb water from the trays 9.
After having passed the greenhouse the plants are ready for
harvest and are sent to a harvester 5 in which the grown
plants are harvested. This corresponds to step 35 in Fig 5.
The plants are inspected preferably before harvesting to
determine that the grown plants fulfil predetermined
requirements on size and or quality. The inspection may be
fully automated using a camera connected to a computer,
which may determine the size and the colour of the plants
from the image taken with the camera. Plants that do not
fulfil the predetermined requirements are preferably sent to
a biogas production plant 28, which preferably is integrated
with or directly connected to the arrangement 1. The
harvested plants may be packed and sold in a facility
integrated with the arrangement 1. Alternatively the plants
are packaged and transported to a sales facility, such as a
supermarket.
After harvest the trays 9, the pots 17 and the growing
medium in the pots 17 are sterilised by moving the trays and
the pots containing the growing medium, into a sterilisation
device 6 in which the trays and pots are subjected to steam.
After the sterilisation device the trays 9 are moved through
a cooling device 30 in which the trays 9, the pots 17 and
the growing medium are allowed to cool off. After the trays
9 have cooled off the trays 9 are transported to the
separating device 40 in which the pots 17 are removed from
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the trays 9 and moved into the sowing device 7 described
above.
Fig 6 shows the separating device 40 or alternatively the
arrangement device 25 (i.e. device for movement of pots) for
movement of pots 17 into or out from a tray 9. The device
25, 40 comprises a robot 42. In the separating device the
robot 42 removes the sterilised pots 17 from the trays 9 and
arranges them on a pallet 41. In the arrangement device
(i.e. device for movement of pots) the robot 42 moves pots
17 with germinated seeds from the pallet 41 to the tray 17.
Fig 7 shows the germination device 8 into which pallets 41
with trays 9 are moved for germination.
Fig 8 shows a cross section of a tray 9 with pots 17 with
plants 32. Fig 9 is an exploded view of a tray 9 with pots
17 and plants 32. As is shown in Fig 7 the tray consists of
a bottom 44 and a lid 45. Holes 34 are formed in the lid in
order to receive the pots 17. Water containers 56 are formed
at both ends of the tray 8.
Fig 10 shows a specific embodiment of harvester 5, referred
to as harvesting unit 46, for harvesting the grown plants
43. Three parallel conveyor belts 47 move trays 9 with
plants 43 into the harvesting unit 46. The empty trays are
moved out of the harvester on second conveyor belts 48. The
harvested plants are transported on third conveyor belts 49.
A camera 50 is provided to inspect the harvested plants.
Alternatively a camera may be arranged to inspect the plants
in the trays before harvest. The sterilisation device 6 may
be integrated in the harvesting unit 46.
Fig 11 shows a cross section of the track 14 in more detail
according to an embodiment of the invention. The track 14
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comprises a first beam 51 and a second beam 52. A tray 9
with a number of pots 17 is supported by the first beam 51
in one end of the tray 9 and by the second beam 52 in the
other end of the tray 9. A conveying device 53 is arranged
5 to travel along the first beam 51 and comprises a tray
moving unit 55 which after passing a tray 9 is arranged to
move the tray 9 one step along the track portion 14. Water
outlets 10 are arranged at the first beam 51. Pots 17, in
which plants 43 grow, are arranged in the trays 9.
10 Fig 12 shows a cross section of the track portion 14 in more
detail according to an alternative embodiment of the
invention. Only the differences between the embodiment of
Fig 5 and Fig 6 will be described. The track portion 14
comprises a third beam 54 on which the conveying device 53
15 is arranged. Furthermore, the second beam 52 is arranged
supporting the tray 9 at a position between the ends of the
tray 9.
