Patent Text
Claims
We claim:
1. Apparatus for =
growth and=20
development of plants comprising: at least one plant development unit=20
including:
an enclosure for enclosing the root portions of plants =
including substantially humidity retaining side and bottom =
walls;
a plant=20
support member defining a generally flat top surface of said enclosure =
and=20
including a layer of web material having apertures formed therein to =
receive=20
plants above the root portions thereof without the provision of an=20
intermediate
element which surrounds a portion of the =
plant;
said=20
plant support member being characterized in that it exposes =
substantially all of=20
the root portions of the plants to the atmosphere contained within said=20
enclosure;
nutrient spraying means for providing a nutrient mist=20
enclosure, said nutrient comprising water and dissolved nitrogen and =
potassium=20
fertilizers;
nutrient collection and recirculation means defined =
in part=20
by a bottom surface of said enclosure;
control means for =
determining the=20
timing of mist provision;
environmental sensor means for =
determining=20
conditions affecting plant transpiration including temperature and =
humidity=20
inside said enclosure;
means for heating said nutrient;=20
and
control means for determining the timing of mist provision, =
said=20
control means being responsive to the outputs of said environmental =
sensor means=20
indicating temperature and humidity for maintaining a desired =
temperature and=20
humidity within said
enclosure;
wherein said spraying means =
comprises=20
a centrally powered pneumatic system which draws liquid nutrient by =
venturi=20
action; and
wherein the nutrient collection and recirculation =
means of=20
each plant development unit is isolated from each other plant =
development=20
unit.
2. Apparatus for aeroponic growth and development according =
to=20
claim 1 and wherein said heating means is operative for pasteurizing the =
nutrient.
3. Apparatus according to claim 1 and wherein said =
pneumatic=20
system operates at relatively low pressure.
4. A method for the =
aeroponic=20
growth and development of plants comprising the steps =
of:
securing the=20
plants above the root portions thereof in an enclosure including =
substantially=20
humidity retaining side and bottom walls and forming part of at least =
one plant=20
development unit so as to expose substantially all of the root=20
portions
thereof to the atmosphere within said enclosure; the =
securing step=20
including placing plants in apertures formed in a layer of web material =
forming=20
part of a plant support member defining a generally flat top surface of =
said=20
enclosure without the
provision of an intermediate element =
surrounding a=20
portion of the plant;
sensing the temperatuer and humidity within =
said=20
enclosure;
heating a liquid nutrient comprising dissolved =
fertilizers;=20
and
providing a nutrient mist directly to the exposed root =
portions of=20
said plants, said nutrient mist comprising said heated liquid=20
nutrient;
said providing step including the steps of providing =
said=20
nutrient mist at selected intervals in response to the sensed =
temperature and=20
humidity in order to maintain a desired temperature and humidity in said =
enclosure,
said providing step also including the steps of =
providing an=20
air flow; supplying a portion of said air flow to a venturi element; and =
drawing=20
heated liquid nutrient by venturi action, said air flow being provided =
to a=20
plurality of plant
development units without permitting =
commlunication of=20
said liquid nutrient between different plant development units. =
Description=20
FIELD OF THE INVENTION
The present invention relates to =
horticulture=20
and more particularly to the growth and development of plants, =
especially the=20
root portions thereof, in a generally gaseous environment into which a=20
nutrient-containing mist is introduced.
BACKGROUND OF THE=20
INVENTION
Aeroponics, or the growth of plants in air has been =
known for=20
some time. F. W. Went describes experimental apparatus for growing plant =
roots=20
in a vaporized nutrient in a publication entitled "The Experimental =
Control of=20
Plant Growth" (1957)
Chronica Botanica Co. Waltham, Mass. at pages =
81-83.=20
Even earlier, in a publication entitled "A Method of Growing Plants in =
Water=20
Vapor to Facilitate Examination of Roots", Phytopathology Volume 32 =
pages=20
623-625, 1942, W. A. Carter described apparatus
for growing plants =
with their=20
roots in water vapor. More recently, in an article entitled "Method for =
Growing=20
Plants Aeroponically", in Plant Physiology (1976) Vol. 57, pages =
344-346, Zobel=20
et al describe an experimental growing box employing a =
rotating
spinner for=20
mist generation.
The above publications, extending over more than =
30=20
years, all relate to experimental devices designed to permit examination =
and=20
relatively free access to plant roots for treatment, all within a =
research=20
context. Aeroponics, until the present,
has been confined to the =
laboratory=20
and has not been conceived of or developed heretofore as a commercial =
technique=20
for facilitating and enhancing plant growth and development.
A =
number of=20
cogent reasons why plants should be grown commercially outside of a soil =
environment have long existed. A major problem particularly in the =
growth of=20
flowers are diseases which reach the plant via the soil. For example,=20
bacteria
such as Fussarium, present in certain soils, causes disease =
in=20
Carnation plants. Other examples of plant diseases which arise from soil =
contact=20
are Botrytis, Sclerotium, Verticilium and Rhizoctonia. Further =
difficulties=20
connected with soil borne
diseases are the difficulty of diagnosing =
and=20
treating the plants and particularly the root portions thereof due to =
the=20
relative inaccessibility thereof in the soil.
Other difficulties =
arise in=20
connection with plants which require special and specific treatment to =
enhance=20
their growth.
For example, in the case of orchids, it has been =
found=20
desirable to supply certain hormones to the growing plants in order to =
enhance=20
their development. The application of such hormones to such plants in a =
soil=20
environment is rendered difficult
and relatively expensive due to the =
relatively large quantity of material required, arising from the fact =
that such=20
hormones must be administered indirectly, via the =
soil.
Hydroponics, or=20
the growth of plants in water, has been known for some time and has been =
the=20
subject of much experimental investigation. Hydroponics has not however =
achieved=20
acceptance for commercial scale plant growth and development. =
One
problem=20
often involved in hydroponics is the lack of adequate ventilation at the =
roots=20
due to the substantially continuous presence of water=20
thereabout.
Hydroponic plant growth apparatus employing a liquid =
spray=20
has been proposed in the patent literature. U.S. Pat. No. 4,059,922 =
discloses a=20
sprayer hydroponic grower in which potted plants are mounted on a =
supporting=20
frame defining a spray
enclosure. The pots are apertured to permit =
the spray=20
to wet the root portions of the plants and to provide nutrients thereto. =
The=20
roots of the plants are supported within the pots by a porous medium =
such as=20
peat and thus the majority of the roots are
not directly exposed to =
the=20
atmosphere and to the spray. As a result of the retention of moisture by =
the=20
porous medium, spray is provided only two or three times during a 24 =
hour=20
period. The fact that the roots are in the main not directly exposed =
to
the=20
atmosphere is believed to have negative implications with regard to root =
diseases.
U.S. Pat. No. 2,431,890 discloses a method and =
receptacle for=20
propagating plants and relates particularly to cuttings to which a spray =
of=20
water is applied to facilitate the development of roots.
U.S. =
Pat. No.=20
3,768,201 discloses a method of sprouting beans which employs a water =
spray=20
which is governed by a timer. The beans to be sprouted are disposed in a =
container having an apertured bottom for draining and the water is=20
recirculated.
German Offenlegungsschrift No. 2,351,508 describes =
a plant=20
growing method in which plants are matured from seed which is placed in =
a porous=20
root permeable base. As the plant develops, the roots extend outwardly =
of the=20
root permeable base. The
base is mounted on a support frame such that =
the=20
base and the exterior roots are exposed to a liquid spray. The porous =
root=20
permeable base shares the apparent disadvantages of the pots of U.S. =
Pat. No.=20
4,059,922, in that a portion of the roots is not
exposed to the =
atmosphere=20
and to the spray and thus becomes susceptible to root =
disease.
SUMMARY OF=20
THE INVENTION
The present invention seeks to overcome =
difficulties=20
associated with the growth and development of plants in accordance with=20
conventional techniques and in accordance with the proposals found in =
the patent=20
literature and to provide apparatus and
methods for commercial scale =
growth=20
and development of plants with substantially all of their roots in a =
gaseous=20
environment.
There is thus provided in accordance with an =
embodiment of=20
the invention apparatus for aeroponic growth and development of a =
multiplicity=20
of plants comprising at least one perforate plant development unit =
including at=20
least one perforate plant
support member adapted to secure plants =
above the=20
root portions thereof and thereby to directly expose substantially all =
of the=20
root portions to the atmosphere; spraying collection and recirculation =
apparatus=20
for providing a nutrient mist directly to the
root portions; and =
comprising=20
control apparatus for determining the timing and duration of mist=20
provision.
Further in accordance with an embodiment of the =
invention, the=20
control apparatus is operative in response to sensed environmental =
conditions in=20
the vicinity of the growing plants, to govern the timing of mist=20
provision.
The mist provision apparatus may be driven by a liquid =
pump or=20
alternatively may comprise a relatively low pressure pneumatic sprayer =
operating=20
as a venturi pump. This latter arrangement has the advantage that it =
enables a=20
central compressor to
be employed to service a number of development =
units,=20
while at the same time isolating the liquid flows in the units to =
inhibit the=20
possible spread of disease.
Additionally, the nutrient liquid may =
be=20
pasteurized to inhibit disease and may be maintained at an elevated =
temperature=20
so as to enable it to be used to regulate the temperature inside the =
growth=20
units.
In accordance with one embodiment of the invention, there =
is=20
provided a generally gas-tight enclosure substantially surrounding at =
least the=20
root portions of the plants and apparatus for introducing a desired =
gaseous=20
atmosphere to the enclosure.
A plurality of plant development =
units may=20
be associated with a single control apparatus for sequentially effecting =
mist=20
generation in a plurality of enclosures according to a preselected=20
program.
Also in accordance with an embodiment of the invention =
here is=20
provided portable aeroponic plant growth and development apparatus =
especially=20
suitable for the development of seeds, seedlings or cuttings and =
comprising; a=20
support member formed of
generally coplanar spaced sheets of screen =
material,=20
and a drainage tray for collecting fluid from mist provided in an =
aeroponic unit=20
and arranged to removably support the support member in spaced =
relationship=20
thereto.
Further in accordance with an embodiment of the =
invention, the=20
support member may be transported and stored in an operating movable =
aeroponic=20
growth unit, such that the plants may be maintained and their growth and =
development continued during
storage and transport and up to the time =
of=20
utilization thereof.
The aeroponic apparatus described =
hereinabove may be=20
supplemented by placing the plants entirely in a sealed environment and=20
introducing a selected treatment agent in gaseous form into the sealed=20
environment for treatment of the plants.
The plant supporting =
member may=20
conveniently be a perforated layer of plastic foam material which =
directly=20
receives the plants.
Also in accordance with an embodiment of the =
invention there is provided mist producing apparatus =
comprising:
a supply=20
conduit having at least one outlet permitting the exit of a pressurized =
flow of=20
liquid; and
a shoulder member arranged adjacent said at least one =
outlet=20
in a selectably adjustable position such that said pressurized flow of =
liquid=20
impinges on a portion of said shoulder member of desired angular =
orientation,=20
for deflection of said
pressurized flow of liquid at a desired=20
angle.
Further in accordance with an embodiment of the invention =
there is=20
provided apparatus for governing the temperature in aeroponic growth and =
development apparatus comprising:
means for sensing the ambient=20
temperature in an aeroponic growth environment; and
means for =
heating a=20
nutrient fluid to be sprayed in said aeroponic growth environment in =
response to=20
the sensed ambient temperature.
The temperature governing =
apparatus may=20
also comprise means for spraying the heated nutrient fluid at times =
determined=20
by the sensed ambient temperature.
Additionally in accordance =
with an=20
embodiment of the invention apparatus is provided for governing the =
humidity in=20
an aeroponic growth environment comprising:
means for sensing the =
ambient=20
humidity in an aeroponic growth environment; and
means for =
governing the=20
spraying of a nutrient fluid in said aeroponic environment in response =
to the=20
sensed ambient humidity.
Additionally in accordance with an =
embodiment of=20
the invention there is provided a nutrient concentrate forming the base =
solution=20
for a nutrient spray suitable for use in aeroponic applications and =
comprising:=20
(in units of weight per hundred
liters of=20
concentrate)
______________________________________ a. =
Ca(NO.sub.3).sub.2=20
. 4H.sub.2 O 29.50 Kg. sequestren 3.47 Kg. b. KNO.sub.3 10.136 Kg. =
NH.sub.4=20
NO.sub.3 2.529 Kg. KH.sub.2 PO.sub.4 3.425 Kg. MgSO.sub.4 . 7H.sub.2 O =
12.665=20
Kg. ZnSO.sub.4 6.00
g. MnSO.sub.4 39.05 g. CuSO.sub.4 2.06 g. H.sub.3 =
BO.sub.3 74.00 g. MoO.sub.3 . H.sub.2 O 0.42 g.=20
______________________________________
Further in accordance with =
an=20
embodiment of the invention there is provided a method of increasing the =
fruit=20
yield of plants comprising the step of:
applying a solution of a=20
substance which induces the initiation and development of flowers and =
fruit set=20
to the plants at a time after the plants have developed the potential =
capability=20
of supporting the development and ripening of the fruit.
The =
inducing=20
solution, according to a preferred embodiment of the invention contains=20
(2-chloroethyl)trimethyl ammonium chloride.
The invention will be =
more fully=20
understood and appreciated from the following detailed description taken =
in
conjunction with the drawings in which:
FIG. 1 is a =
pictorial=20
illustration of a commercial aeroponic growth and development system =
constructed=20
and operative in accordance with an embodiment of the present=20
invention;
FIG. 2 is a schematic illustration of the nutrient =
containing=20
mist generation and recirculation system constructed and operative in =
accordance=20
with an embodiment of the invention;
FIG. 3 is a schematic =
illustration=20
of the control circuitry constructed and operative in accordance with an =
embodiment of the invention;
FIG. 4 is a sequence diagram =
illustrating=20
the operation of the apparatus constructed and operative in accordance =
with a=20
preferred embodiment of the invention;
FIG. 5 is a schematic =
illustration=20
of a portable aeroponic growing unit constructed and operative in =
accordance=20
with an embodiment of the invention;
FIG. 6 is a pictorial =
illustration=20
of an aeroponic growing system employing the movable seed=20
containers;
FIG. 7 is a schematic illustration of a =
hydroponic/aeroponic=20
growth and development system constructed and operative in accordance =
with an=20
embodiment of the invention.
FIG. 8 is a schematic illustration =
of a=20
spray head constructed and operative in accordance with an embodiment of =
the=20
invention;
FIGS. 9 and 9' is a schematic illustration of spray =
control=20
circuitry constructed and operative in accordance with an embodiment of =
the=20
invention;
FIGS. 10 and 10' is a schematic illustration of an =
alternative=20
embodiment of control circuitry; and
FIG. 11 is a schematic =
illustration=20
of a further embodiment of the invention
DETAILED DESCRIPTION OF THE =
INVENTION
Referring now to FIG. 1, there is shown in partly =
pictorial,=20
partly schematic illustration an aeroponic plant growth and development =
system=20
constructed and operative in accordance with an embodiment of the=20
invention.
A plurality of aeroponic growth and development units=20
indicated generally by reference numeral 10 are disposed typically =
alongside=20
each other and one above another within a building structure (not shown) =
which=20
is designed to provide a desired
degree of control over the =
temperature,=20
humidity and light environment therein. The horizontal spacing between =
the=20
growth and development units need only be sufficient to permit an =
operator to=20
casually pass therebetween when tending the plants and is
typically =
50 cms.=20
while the vertical spacing between the growth and development units is=20
determined by the amount of space required for plant growth as well as =
the=20
particular conditions of natural illumination required. Thus, the =
vertical=20
spacing may
be as little as 40 cms. between adjacent plant surfaces. =
It is=20
noted that the growing surface of the units may either be flat or =
inclined, with=20
a view towards the most efficient use of solar illumination. =
Alternatively,=20
artificial light may be
employed either in combination with or =
instead of=20
natural illumination. Typically the top surfaces of the growth and =
development=20
units are separated from each other by a distance of 2 meters. However, =
this=20
distance may vary greatly and may be as low as
40 cms. for root =
development=20
of Carnation cuttings.
It is appreciated that any number of =
growth and=20
development units may be disposed one on top of the other with suitable =
spacing=20
therebetween, the number of such units in a stack being limited only by =
the=20
structural and logistical considerations
involved. Thus, it will be=20
understood that the intensivity of plant growth per unit area of =
available land=20
is virtually unlimited other than by economic factors.
Growth and =
development units 10 are generally rectangular and comprise a support =
frame 12=20
having legs 14 and a peripheral supporting structure 16 mounted thereon. =
Disposed on structure 16 is a plant support member 18 typically a screen =
formed=20
of
a plastics material and having openings in dimension 0.7 cms. by =
0.7 cms.=20
Above the plastics material there is provided inert particulate material =
such as=20
foam polystyrene, volcanic ballast, vermiculite, peat or small gauge =
gravel.=20
This material is
employed to further support the plants and to =
maintain a=20
desired orientation thereof in relation to the surface defined by screen =
18. The=20
use of such material permits the plants to be arranged in a manner such =
that=20
only the collar above the root
portions thereof contact the inert =
material=20
such that good ventilation is provided in order to reduce problems of =
pests and=20
diseases.
In accordance with an alternative embodiment of the =
invention,=20
plant support member 18 may comprise a sheet of plastic foam, such as=20
polystyrene, apertured at suitable intervals to receive plants for =
support=20
thereof.
The root portions 25 of respective plants 27 are =
disposed below=20
the surface screen 18 and within a volume which is defined generally by =
the=20
peripheral legs 14 of units 10. Substantially all of the roots are thus =
exposed=20
to the atmosphere.
Disposed adjacent the root portions 25 are a =
series of=20
mist generating units 30 which are disposed in a generally linear array =
and=20
coupled for fluid communication with a fluid supply line 32. Fluid =
supply lines=20
32 of the respective units 10 are
coupled in turn to fluid =
distribution means=20
34 which will be described hereinafter in greater =
detail.
Disposed below=20
mist generating means 30 and substantially covering the bottom surface =
of units=20
10 is a drain surface member 36, typically a plastic sheet which is =
arranged,=20
configured and disposed so as to act as a drain for fluid emitted by=20
mist
generators 30 and falling by action of gravity onto drain =
surfaces 36.=20
Drain surfaces 36 are in turn connnected with conduits 38 to fluid =
distribution=20
means 34 to permit recycling of the nutrient containing =
fluid.
Mist=20
generating means 30 typically comprise sprayers of the Naan or Lego =
brands=20
manufactured in Israel and having a capacity of approximately 15-30 =
liters per=20
hour. Frame 12 is typically formed of wood covered with a plastic =
coating to=20
prevent
damage thereto from the circulating fluids.
It is =
appreciated=20
that in accordance with an alternative embodiment of the invention, =
support=20
frames 12, instead of being fixed structures as illustrated in FIG. 1 =
may be=20
sliding structures akin to drawers and may be disposed in a support=20
member
akin to a drawer cabinet. In such an embodiment the plant =
support=20
member may be advantageously removably mountable on the sliding frame =
and the=20
mist generation sprayer may either be mounted on the support frame or=20
alternatively a series of such sprayers
may be arranged between =
successive=20
drawers or rows of drawers so as to provide desired wetting of the root =
portions=20
of the plants disposed therein.
According to an alternative =
embodiment of=20
the invention each plant support member 18 disposed on a sliding drawer =
type=20
frame could be associated with its own drainage surface 36. As a further =
alternative a single drainage surface 36 underlying a
plurality of=20
respectively vertically stacked plant support members may be =
employed.
In=20
accordance with a preferred embodiment of the invention wall sections of =
polyethylene sheeting are disposed peripherally of frame 12 so as to =
extend=20
generally between surface 18 and drainage surface surface 36. Wall =
sections 38=20
thus define
together with surface 36 and screen 18 an enclosure 40 =
within=20
which the root development takes place. Thus in accordance with a =
preferred=20
embodiment of the invention mist generating means 30 are operative to=20
substantially fill enclosure 40 with a
nutrient containing mist of =
selected=20
composition at specified times and for selectable specified=20
durations.
Wall portions 36 are generally designed so as to be =
readily=20
movable, permitting an operator to readily gain access to plant roots =
for=20
examination or treatment thereof.
According to one embodiment of =
the=20
invention wall sections 36 are joined to drainage surface 36 and to the=20
periphery of screen 18 in a generally gas sealed arrangement thus =
permitting the=20
temperature and humidity of the environment within
enclosure 40 to be =
controlled. Further according to this embodiment of the invention gas =
generating=20
means 42 may be provided for substantially filling enclosure 40 with a =
desired=20
gaseous atmosphere. The gas generating means 42 may comprise a =
container
of=20
pressurized gas or typically a chemical or other gas generator together =
with a=20
blower.
The desired gaseous atmosphere may be carbon dioxide and =
oxygen=20
in a controlled proportion selected to correspond to the optimal mixture =
for the=20
development of a given type of plant.
Alternatively, a fertilizer =
such as=20
ammonia in gaseous form or a hormone such as ethylene also in gaseous =
form may=20
be applied to the plant for selected treatment thereof. Other types of =
plant=20
treatment agents in gaseous form may similarly be
employed.
In =
accordance with an embodiment of the invention the generally gas-tight =
enclosure=20
may encompass also the top portion of the plants as indicated in phantom =
by the=20
enclosure structure 41. As a alternative only the top portions of the =
plants=20
may
be enclosed in a gas-tight enclosure while the root portions =
thereof may=20
be left open to the atmosphere.
Wall portion 39 and drainage =
surface 36=20
may be formed either of a transparent or translucent plastics material =
or=20
alternatively of a generally opaque plastics material depending on =
whether it is=20
desired that root development take place in a
generally light or =
generally=20
dark environment. Alternatively wall portions 39 and drain surface 36 =
may be=20
formed of any other suitable materials having any suitable light=20
transmissivity.
In a further alternative, wall portions 39 may be =
eliminated and drainage surface 36 may be replaced by any other suitable =
fluid=20
control means.
Referring now to FIG. 2 there is shown in =
schematic form=20
the fluid circulation system of the embodiment of the invention shown in =
FIG. 1=20
including fluid distribution means 34 and the electrical control system=20
therefor.
A main supply conduit 50 is coupled to branch supply =
lines 60,=20
62, 64, 66, 68 and 70 each corresponding to a single growth and =
development unit=20
10 (FIG. 1) and coupled to respective mist generators 30, via respective =
conventional magnetically
operated valves V1, V2, V3, V4, V5 and V6 =
which are=20
in turn controlled by programmable timing means 72 for automatic =
operation. The=20
fluid circulated in the system herein considered, is generally water =
based and=20
comprises a nutrient mixture selected to
correspond to the particular =
needs=20
of the plants being grown at a particular time. The mixture may also =
comprise=20
hormones or other treatment substances for enhancing growth and =
development or=20
preventing disease.
Fluid is supplied into conduit 50 from pump =
means 74=20
which may be one or more conventional pumps operated in response to =
control=20
signals from programmable timing means 72. Programmable timing means 72 =
and pump=20
means 74 typically operate on line
power. In accordance with a =
preferred=20
embodiment of the invention, an emergency backup battery system may also =
be=20
provided. Preferably, pump means 74 operates at a relatively low =
pressure=20
thereby to enhance operating lifetime of the pumps and of =
the
remainder of=20
the fluid circulation system. Pump 74 receives fluid mainly from =
drainage sumps=20
76 in which is collected fluid drainage from the respective growth and=20
development units 10 as described below in connection with FIG. 1. One =
or more=20
drainage
sumps may be provided and arranged in accordance with =
particular=20
design criteria. Initial supply and replenishment of circulating fluid =
is=20
provided via a conduit 78 and valve 80 from a storage tank 82 which =
holds=20
nutrient containing fluid. Valve 80 may
either be automatically =
controlled or=20
alternatively manually controlled. This valve is opened when it is =
necessary to=20
add additional fluid to the circulating system.
An alternative =
source of=20
fluid is provided from a conventional pressurized water supply such as =
that=20
provided by many municipalities and local authorities via a valve 90 and =
purifying means 92 which may include a filter and ion =
exchange
apparatus.=20
Valve 90 opens in the event of an electrical power failure (i.e. the =
failure of=20
the line power and of a backup battery power) which could prevent the =
proper=20
operation of pump means 74 and programmable timing means 72 and ensures =
that in=20
the
event of the failure of either the pump means or the programmable =
timing=20
means an adequate supply of fluid is provided via conduit 50 for mist=20
generation. In this connection it should be appreciated that valves =
V1-V6 are=20
designed to remain open in the
event of a power failure affecting =
their=20
performance. Programmable timing means 72 is illustrated in block =
diagram form=20
illustrated in FIG. 3 and comprises a pulse generator 100 which supplies =
a=20
stream of periodic pulses to a frequency divider 102. The
output of =
frequency=20
divider 102 is supplied as a set input to a flip flop 104 which in turn =
provides=20
an enable output to a pulse generator 106 whose output in turn governs =
the duty=20
time, that is the duration of operation of a given valve and thus=20
the
duration of mist generation in a given growth and development =
unit. Pulse=20
generator 106 provides a stream of periodic pulses to a frequency =
divider 108=20
whose output in turn is supplied to a shift register 110. Shift register =
110 in=20
turn provides a
reset output to flip flop 104, frequency divider 108 =
and to=20
an internal reset of shift register 110 itself. The outputs of shift =
register=20
110 serve as enable inputs to respective solonoids 1-6 which operate =
respective=20
valves V1-V6.
Frequency divider 102 also provides an output to a =
relay P1=20
which governs the operation of pump means 74 (FIG. 2).
The cycle =
of=20
operation of programmable timing means 72 may be better appreciated by =
reference=20
additionally to FIG. 4 which indicates the sequence of operation of the =
control=20
apparatus. Line A indicates the outputs of pulse generator 100 =
which
are=20
continuous during the entire time the system is in operation and line B=20
indicates the triggering output of frequency divider 102 which places =
flip flop=20
104 in the set state. Line C indicates the set output of flip flop 104 =
which=20
causes pulse
generator 106 to produce a chain of pulses illustrated =
at line=20
D. Line E indicates the output of frequency divider 108 which, when =
supplied to=20
shift to register 110, sequentially energises solonoids 1-6 for a =
predetermined=20
amount of time. Subsequent to
the energization of solonoid 6 the =
reset output=20
of shift register 110 causes flip flop 104 to return to the set state, =
thus=20
terminating for the time being the generation of pulses by pulse =
generator 106=20
and terminating the duty time of pump means 74 as
illustrated at line =
G.
A particular feature of the present invention is the relative=20
simplicity of the electrical and electronic apparatus comprising =
programmable=20
timing means 72.
Due to the appreciation that this apparatus is =
designed=20
for the use of persons not expert in electronics or the maintenance of=20
electronic apparatus, the apparatus is designed in modular form with =
push-pull=20
type connectors which permit spare
modulii, kept on hand for =
emergencies, to=20
be readily and immediately substituted for malfunctioning modulii in the =
system=20
without requiring skill on the part of the operators or =
tools.
Reference=20
is now made to FIG. 5 which illustrates portable apparatus for the =
growth and=20
development of seeds, seedlings or cuttings and for the transport =
storage and=20
marketing of the finished products. A generally planar sandwich is =
formed=20
of
one or two sheets of plastic coated metal screen having 1 cm =
square=20
openings. Very high densities of approximately 10,000 cuttings per =
square meter=20
may be supported in the sandwich. The support structure defined by the =
sandwich=20
and containing the seed,
seedlings or cuttings may initially be =
introduced=20
into a container of IBA Indole butylic acid powder for initiation of =
root=20
growth. The support sandwich 120 may then be transferred to an aeroponic =
growth=20
and development unit 10 which is substantially
identical to the unit=20
illustrated in FIG. 1 except that the screen assembly 18 and particulate =
matter=20
20 is not present, sandwich 120 being substituted therefor. Aeroponic =
growth and=20
development is then allowed to continue for a suitable time=20
typically
approximately three weeks and support member 120 containing =
the=20
thus developed plants may be removed from unit 10 and suspended a =
desired=20
distance above a generally planar water containing tray 130 by means of =
support=20
members 140 which may be associated
with the tray. The vertical space =
for=20
separation between support sandwich 120 and tray 130 is selected to =
permit the=20
roots of the plants supported by sandwich 120 to reach a sustaining =
fluid=20
contained in tray 130 and to be nourished thereby during
transport =
and=20
subsequent storage until transplantation of the plants. It is =
appreciated that=20
the combination of support sandwich 120 and tray 130 as a =
transportation,=20
storage and marketing device has a number of advantages. Primary among =
these is=20
the
possibility of transporting such plants over relatively long =
distances by=20
relatively slow means of transport to distant markets. Similarly plants =
may be=20
sustained for a relatively long time in cold storage to await favourable =
market=20
conditions.
Thirdly, plants may be provided with nourishment until =
the time=20
of actual use, thus greatly simplifying distribution and planting =
procedures.=20
The condition of the roots can readily be inspected by interested =
parties at any=20
stage of transport or storage
as well as at the point of=20
sale.
Referring now to FIG. 6 there is shown in schematic form an =
aeroponic growth and development unit essentially designed for the =
germination=20
and development of plants from seeds and subsequent transport and =
marketing of=20
the thus developed plants.
A perforate support member 40 is disposed =
above=20
mist generating means 142. A plurality of seed containing dishes 144 are =
disposed at the perforations of support 140 such that the lower portion =
of=20
containers 144 lies within the mist generating range of
means 142. =
Containers=20
144 are generally dish-shaped having the lower portion thereof =
perforated to=20
permit roots developed therein to exit therefrom. One or a plurality of =
seeds is=20
conveniently placed in container 144 together with a =
germination
enhancing=20
substance such as Gibberalic Acid GrA.sub.3 and its contents are then =
subjected=20
to a mist generated from below. Preferably a spray of nutrient =
containing fluid=20
is also directed at the contents of container 144 from above by sprayer =
means=20
146.
Upon development of roots the spray from means 146 may be =
discontinued=20
and upon completion of the desired development, containers 144 may be =
removed=20
from units 10. The plants developed therein may be transported, stored =
and=20
marketed in the original
containers or placed directly in =
correspondingly=20
sized flower pots. For this purpose fluid containing apparatus (not =
shown)=20
similar to trays 130 in FIG. 5 may be employed.
Referring now to =
FIG. 7=20
there is shown apparatus for hydroponic-aeroponic growth and development =
of=20
plants comprising a plurality of plant growth and development units 150, =
each=20
comprising a plant support member 152, typically a screen, and =
a
liquid=20
container 154 having a liquid inlet 156 and a liquid outlet =
158.
In=20
accordance with a preferred embodiment of the invention, plant growth =
and=20
development units 150 are arranged to define first, second and third =
pluralities=20
of units 150 hereinafter referred to by reference numerals 160, 162 and =
164=20
each
arranged at a different height so as to permit flow of liquid =
from a=20
first plurality of growth and development units 160 by means of gravity =
to a=20
second plurality of such units 162 and then to a third plurality of such =
units=20
164.
Nutrient containing liquid is supplied to first plurality =
160 via a=20
manifold 166 which in turn receives the liquid from a pump 168 via an=20
electro-magnetically controlled valve 170.
Units 150 of first =
plurality=20
160 are interconnected by liquid conduits 172. Drainage from units 150 =
of first=20
plurality 160 is effected via a fluid channel 174 governed by an=20
electro-magnetically controlled valve 176. The liquid drained =
via
channel 174=20
is typically supplied to units 150 of second plurality 162 by means of =
gravity=20
and distributed between the various units by means of communication =
conduits=20
178. Similarly, drainage from second plurality 162 is effected by =
gravity via=20
a
channel 180 governed by electro-magnetically controlled valve 182 =
and the=20
fluid thus drained is supplied to third plurality 164, the units thereof =
being=20
interconnected by communication channels 184.
Drainage from third =
plurality 164 is effected via a channel 186 controlled by an =
electro-magnetic=20
valve 188 and the fluid drained is resupplied to the first plurality 160 =
of unit=20
150 via manifold 166 and valve 170 or alternatively returned to =
a
storage=20
container 190 via a channel 192 governed by an electro-magnetically =
controlled=20
valve 194.
The operation of the various electro-magnetically =
controlled=20
valves is governed by timer means 200 which may comprise conventional=20
programmable control apparatus.
Operation of the =
hydroponic-aeroponic=20
system described hereinafter will now be summarized. In order to =
overcome a=20
serious disadvantage of hydroponics which concerns the lack of =
ventilation of=20
the root portions of plants lying in nutrient
containing fluid, the =
fluid is=20
supplied only at predetermined intervals and not continuously so as to =
permit=20
ventilation of the roots in the absence of the surrounding fluid. Thus, =
in=20
response to timer control signals, nutrient containing fluid =
is
supplied to=20
first plurality 160 and fills the units 150 thereof up to a =
predetermined level.=20
After a predetermined duration of time also determined by timer 200 most =
or all=20
of the fluid in unit 150 is drained via valve 156 and passes to the=20
second
plurality 162 and thence to the third plurality.
A =
certain=20
amount of nutrient containing liquid may be retained under certain =
circumstances=20
continuously in units 150 to prevent drying out of the roots. The =
duration and=20
periodicity of the presence or absence of nutrient containing liquid at=20
the
roots of plants is determined in advance and forms the basis for =
the=20
programming of timer 200 as well as the configuration of the apparatus. =
It is=20
appreciated that once liquid has been supplied to the first plurality =
160, pump=20
168 may be disengaged
while the remainder of the circulation cycle =
takes=20
place by gravity.
Reference is now made to FIG. 8 which =
illustrates a=20
spray head constructed and operative in accordance with an embodiment of =
the=20
invention and having particular utility in aerophonic applications. A =
water=20
conduit 300, typically a generally
cylindrical tube having a threaded =
inlet=20
302 and a sealed opposite end is formed with one or more water exit =
openings=20
306. In the preferred embodiment of the invention illustrated in FIG. 8, =
four=20
such water exit openings are uniformly arranged about the
periphery =
of=20
conduit 300 in a single plane, which may be defined by a peripheral =
recess 308.=20
A generally disc-shaped deflecting member 310, shown in section, is =
seated on=20
conduit 300 at a selected position thereon determined by a support =
member=20
312,
such as a frictional member or washer.
Deflecting member =
defines=20
a generally flat portion 314 and a generally upstanding portion 316 =
which are=20
joined by a curved inner surface 318. It may be appreciated that a =
liquid, such=20
as water, exiting from openings 306 under pressure will
impinge upon =
the=20
inner surface 318. The precise positioning of member 310 is selected in=20
accordance with the desired angle of surface 318 it is desired that the =
liquid=20
flow impinge upon.
Thus if a relatively narrow spray is desired, =
i.e.=20
defining a cone 320 of relatively small angle .alpha., a member 310 is =
moved=20
relatively upwards with respect to openings 306. If a wider spray is =
desired,=20
member 310 is moved relatively
downwards with respect to openings=20
306.
According to alternative embodiments of the invention, more =
or fewer=20
openings 306 may be provided and the openings need not necessarily lie =
in the=20
same plane. Furthermore the inner surface 318 of member 310 may be made =
in any=20
desired
configuration suitable for controlling the spray=20
configuration.
Turning now to the automatic temperature and =
humidity=20
control provided in accordance with an embodiment of the invention, =
reference is=20
now made to FIG. 9. The control system will be described with reference =
to an=20
aeroponic growing installation
which comprises a plurality of growing =
enclosures, each referred to as sub-units. A plurality of sub-units are =
grouped=20
together for spray control by a single time-sharing circuit and are =
considered=20
as a unit. A plurality of such units may be
interconnected with a =
single=20
supply of nutrient solution in the overall system.
Each sub-unit =
is=20
equipped with a dry thermometer and a wet thermometer (not shown) which =
together=20
provide indications both of temperature and humidity. For each sub-unit, =
inputs=20
from respective dry and wet thermometers are supplied to=20
respective
amplifiers 350 and 352, whose outputs are applied to =
respective=20
positive and negative inputs of a comparator 354. The output of =
comparator 354=20
is supplied to a humidity recorder (not shown).
The output of =
amplifier=20
350 is supplied to a temperature recorder (not shown), to a heating =
threshold=20
detector 356, which provides a nutrient tank heater control signal, and =
to a=20
low-temperature threshold detector 358, which supplies an =
output
signal to a=20
spraying request OR-gate 360.
The output of comparator 354 is =
also=20
supplied to a humidity threshold detector 362 which provides an output =
to=20
OR-gate 360.
An oscillator 364 provides a clock input to a binary =
counter=20
366 having a Q5 output which determines the duration of spraying for a =
given=20
sub-unit and a Q14 output which determines the interval between spraying =
cycles=20
for a given sub-unit. The
Q14 output of counter 366 is supplied to an =
input=20
of OR-gate 360.
OR-gate 360 provides an output signal to a =
Restart AND=20
gate 368, which also receives a start-condition input signal from time =
sharing=20
circuitry 370, which will be described hereinafter and which is common =
for each=20
unit. The output of AND-gate
368 is supplied via a diode 372 to the =
RESET=20
input of binary counter 366, and is also supplied as a SET input to a =
Flip-Flop=20
374. Flip-Flop 374 also receives a RESET input from the Q5 output of =
counter 366=20
via a diode 376. A Power-On Reset signal
supplied from circuitry 377 =
supplies=20
a signal to the RESET input of counter 366 via a diode 378 and to the =
RESET=20
input of Flip-Flop 374 via a diode 380. The output of Flip-Flop 374 is =
supplied=20
to a sprayer control such as a solenoid valve or pump.
Each of =
the=20
sub-units of the control system corresponding to sub-units of the =
growing=20
apparatus are constructed substantially as described above. The output =
of=20
Flip-Flop 374 of each sub-unit is supplied to a common bus 390 which is=20
connected to
the ENABLE input of a RESTART CONDITION shift register =
392,=20
which receives clock pulses from a RESTART oscillator 394. The three =
outputs of=20
shift register 392 are supplied to Power On Reset circuitry 377 and to=20
respective AND gates 368 as START
CONDITION signals for the various=20
sub-units. Bus 390 is connected also to a Pump Control Drive circuit=20
391.
The above description has dealt with a complete unit. A =
plurality of=20
units may be constructed, each substantially as the unit described above =
and may=20
be associated with a common solution measuring circuit or alternatively =
with=20
corresponding
individual solution measuring circuits depending on the =
nutrient supply configuration of the system.
The solution =
measuring=20
circuit 400 comprises an oscillator 402 which provides an output to a =
solution=20
conductivity measuring bridge 404. Bridge 404 provides output signals to =
respective positive and negative inputs of an amplifier 406 =
whose
output is=20
identified as a % Solution Test signal. The output of amplifier 406 is=20
additionally supplied to a conductivity threshold circuit 408 which =
provides a %=20
Solution Alarm signal, indicating a danger condition in the solution=20
concentration.
The operation of the above-described circuitry =
will now be=20
briefly summarized:
The purpose of the control circuitry is to =
provide=20
the capability to vary the amounts of nutrients solution in the =
aeroponic growth=20
environment according to the humidity and temperature prevailing in =
them. One=20
aim is to prevent a situation in
which the ambient humidity falls =
below a=20
minimum threshold. When the humidity falls below this threshold spraying =
of the=20
nutrient into the growth unit is activated subject to time sharing =
constraints.=20
Similarly, temperature control is achieved by
monitoring the ambient=20
temperature. When an insufficiently high temperature is sensed, the =
frequency of=20
spraying is increased with the resultant increase in relative humidity. =
When the=20
ambient temperature in the growth environment reaches an even=20
lower
threshold, a thermostat-equipped heater located in a nutrient =
storage=20
tank is operated to increase the heat of the nutrient spray and thus =
increase=20
the temperature of the growth environment.
Spraying is commenced =
when a=20
START CONDITION signal is provided. This occurs under one of the =
following=20
conditions, (taken in the alternative):
1. Too low =
humidity
2. Too=20
low temperature
3. The time interval between sprayings exceeds a =
given=20
threshold.
The Start Condition signal is operative to enable =
reset of the=20
binary counter 366, thus causing the Q14 output thereof to go to a Low =
state.=20
The START CONDITION signal also enables Flip-Flop 374 to be Set which =
causes an=20
enable signal to be sent
to the Sprayer Control circuitry which =
results in a=20
renewal of spraying. It may be appreciated that operation of the =
sprayers in any=20
given sub-unit is dependent on that sub-unit being in START CONDITION as =
determined by the time sharing circuit. In the
absence of exceedance =
of=20
thresholds, normal timed operation determined by the setting of =
oscillator 364=20
and counter 366 continues. When a threshold condition occurs, spraying =
is=20
recommenced earlier than would otherwise occur subject to=20
time-sharing
constraints.
Reference is now made to FIG. 10 =
which shows=20
an alternative embodiment of control circuitry based on a =
microprocessor. An=20
input analog multiplexer 450 receives various inputs from the various =
units and=20
subunits of the growth apparatus, such as
indications of temperature, =
humidity, nutrient supply and nutrient concentration as well as the =
conditions=20
of the mains power and of a standby power source.
Multiplexer 450 =
communicates, as via a A/D converter 452, through a Data Bus, Address =
Bus and=20
Control Bus with a microprocessor such as a M 6800 Based Microcomputer =
including=20
Random Access memories and interchangeable ROMs. An =
output
multiplexer/Latch=20
and Execution Circuits 545 provides Alarm outputs and controls for =
pumps,=20
heaters, fans, flow valves and relays as needed to operate the =
aeroponics sytem.=20
The system is capable of automatically engaging standby power if=20
necessary.
The composition of a nutrient mixture suitable for use =
in the=20
aeroponics system of the present invention will now be discussed =
together with=20
techniques for improving crop yields.
A concentrated stock =
solution is=20
described hereinbelow for use, when diluted, preferably to a ratio of=20
1:5.times.10.sup.5 in the aeroponics system described hereinabove. The =
solution=20
has been found experimentally to be particularly suited for
the =
growth and=20
development of tomato plants. The solution contains constituents a and b =
which=20
prior to dilution are kept in separate containers to prevent =
precipitation of=20
essential ingredients thereof. According to a preferred embodiment of=20
the
invention the composition of the solution is as=20
follows:
______________________________________ a. =
Ca(NO.sub.3).sub.2 .=20
4H.sub.2 O 29.50 Kg. sequestren 3.47 Kg. b. KNO.sub.3 10.136 Kg. =
NH.sub.4=20
NO.sub.3 2.529 Kg. KH.sub.2 PO.sub.4 3.425 Kg. MgSO.sub.4 . 7H.sub.2 O =
12.665=20
Kg. ZnSO.sub.4 6.00
g. MnSO.sub.4 39.05 g. CuSO.sub.4 2.06 g. H.sub.3 =
BO.sub.3 74.00 g. MoO.sub.3 . H.sub.2 O 0.42 g.=20
______________________________________
Further in accordance with =
an=20
embodiment of the invention there is provided a technique of increasing =
crop=20
yields by applying to the plant once it has developed the potential =
capability=20
to support the development and ripening of fruit a solution
which =
serves to=20
induce the initiation and development of flowers and fruit =
set.
In=20
accordance with experiment it has been found helpful to provide, at =
initial=20
stages of plant growth, the basic nutrient solution described above in a =
spray=20
cycle of 20 minute duration separated by an interval of 10 minutes. =
After=20
approximately
one month of growth, or when two trusses of flowers are =
developed the solution is replaced by constituent b described above =
together=20
with 0.1 gram of C.C.C. (2 chloroethyl)Trimethyl ammonium chloride to=20
approximately 33 Kg. of constituent b.
Reference is now made to =
FIG. 11=20
which shows a plant growth unit constructed and operative in accordance =
with an=20
alternative embodiment of the invention and in which a relatively low =
pressure=20
high volume flow of air is employed as a propellent to
produce a =
nutrient=20
liquid spray. It is appreciated that while only a single growth unit is =
here=20
illustrated, the apparatus is designed for a plurality of such growth =
units each=20
operated by a central, common air compressor and control system, =
operative
in=20
response to environmental conditions in accordance with a predetermined =
program.=20
A particular feature of the arrangment illustrated herein is that the =
liquid=20
nutrient supply for each growth unit is isolated and does not mix with =
the=20
nutrient supply
for other growth units. This is important for the =
purpose of=20
preventing the possible spread of disease and additionally for enabling=20
different nutrient solutions to be used in different growth units =
belonging to=20
the same system.
A growth unit 510 having supported hereon a =
plurality of=20
plants 527, such that the root portions thereof are substantially =
exposed to the=20
atmosphere has a drainage surface 536 which is coupled to a=20
heating/pasteurization tank 537 via a conduit
538 which permits =
gravitational=20
drainage of the nutrient liquid from surface 536 into tank 537.
A =
nutrient liquid spray is provided in the vicinity of the plant roots, =
indicated=20
by reference numeral 525 by a plurality of spray heads 530. Spray heads =
530=20
define nozzles designed to accomodate a relatively high volume, low =
pressure,=20
e.g. 1
atm above atmospheric pressure flow of pressurized air, and =
are formed=20
as a venturi with a side channel through which the liquid nutrient is =
drawn by=20
the venturi effect of the air flow via a conduit 540 from a liquid =
nutrient=20
supply line 542.
The relatively high volume air flow produces a=20
relatively fine mist in the vicinity of the plant roots.
It may =
be=20
appreciated that the liquid nutrient circulation system is a passive =
systme,=20
other than for the pressurized air propulsion, and defines a closed =
system in=20
which the liquid nutrient from one growth unit does not communicate with =
another
growth unit. The pasteurization/heating tank 537 provides =
desired=20
heating of the liquid nutrient. Where pasteurization is indicated for =
disease=20
prevention or other purposes, the liquid nutrient is heated to an =
appropriate=20
temperature. In such a case,
the liquid nutrient may then be cooled =
to a=20
desired degree with or without the use of an auxiliary holding tank or =
heat=20
exchanger (not shown).
Where pasteurization is not required, the=20
pasteurization/heating tank may be employed for selectably heating the =
liquid=20
nutrient to provide temperature control of the root environment as =
described=20
above in connection with the control systems of
FIGS. 9 and =
10.
The=20
pasteurization/heating tank is governed by control circuitry 560 which =
may be=20
control circuitry of the type described in either of FIGS. 9 and 10 or =
any other=20
suitable control circuitry. Control circuitry recieves humidity and=20
temperature
inputs from respective sensors 562 and 564 inside each =
growth=20
unit and from respective sensors 566 and 568 outside of the growth =
units.=20
Depending on the instructions provided in advance to the control =
circuitry, it=20
may operate both the heater and spray
producing apparatus in response =
to one=20
or more of these inputs in any combination. A predetermined timing =
program may=20
be used additionally during all or part of a growth cycle.
The =
spray=20
producing apparatus 570 typically comprises a pneumatic valve which =
selectively=20
permits a flow of pressurized air from a compressor or a common air line =
to=20
reach the spray heads 530. In order to reduce insofar as possible the=20
required
capacity of the air compressor, the control circuitry =
operates the=20
spray producing apparatus associated with each control unit in a =
staggered=20
arrangement as described hereinabove.
The periodicity of the =
nutrient=20
sprays is determined by the estimated or actual dryness of the =
atmosphere in=20
which the plants are situated. It is desired to suit the spray pattern =
to the=20
rates of transpiration and evaporation of the plants. Wet
and dry=20
thermometers are employed to provide a spray pattern which is responsive =
both to=20
temperature and to humidity. A typical exemplary spray pattern is =
indicated=20
below:
______________________________________ Time Measured =
Conditions=20
Spray duration between sprays Temp. .degree.C. Rel. Hum. % Seconds =
Minutes=20
______________________________________ 0-10 75-100 40 5 10-15 75-100 40 =
10 15-20=20
75-100 40 20
20-30 75-100 40 60 30-40 40-75 40 10 30-40 0 -40 40 5=20
______________________________________
Where the measured =
temperature is=20
between 0.degree. and 15.degree. C., the liquid nutrient is maintained =
at about=20
30.degree. C. for heating of the plant environment.
It is a =
particular=20
feature of the invention that relatively frequent sprays are provided. =
The=20
present invention may thus be contrasted with prior art spray systems in =
which=20
the plant roots are at least partially enclosed in a liquid =
retaining
medium=20
and which do not involve frequent spraying.
It is a particular =
feature of=20
the present invention that the spray pattern can be selectively and =
changeably=20
controlled either by preprogramming or in response to currently measured =
environmental parameters or by any combination of the two.
The =
present=20
invention is not limited to what has been specifically shown and =
described=20
herein. Rather, the scope of the present invention is defined only by =
the claims=20
which follow:
* * * * *