Note: Descriptions are shown in the official language in which they were submitted.
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0 l 559-86 GW15: jy
AUTOMAT :~ C ~ RR IGAT I ON DEV I C E ~OR C U LT I VA~ E D SO I L
The invention relates to an automatic irrigation
de~ice for cultivated soil.
Cultivated soil is understood to mean earth, humus,
and the like, suitable for gardening or agriculture and
planted or sowed with seedlings or plants.
Summary of the invention
According to one aspect of the present invention an
automatic irrigation device for cultivated soil, comprising a
wall surrounding a reservoir for water and having an opening
for introduction of the water, a removable sealing means
airtightly sealing said opening~ said wall having two passages
for the discharge of water from said reservoir and for the
entrance of air into the reservoir, said reservoir being
airtightly sealed by said wall and said sealing means except
for said two passages, said two passages each having an
outside end intended ~or adjoining soil to be automatically
irrigated, said outside ends of said two passages being
spaced-apart by a distance which is less than n-3 cm, wherein
n is the number of liters of the reservoir volume, said
passages having diameters in the range of 0.5-5 mm, whereby
when soil to be automatically irrigated covers the outside
ends of the two passages water from the reservoir can flow out
of one of said passages only upon entrance of air through the
other of said passages and the flow is stopped when the water
after passing said distance reaches the outside end of the
other of said passages, preventing the further entrance of air
through the other of said passages allowing a vacuum to be
formed in the reservoir above the level of the water therein.
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Br_ef Descrlpt on of_the Drawings
The invention and its preferred features will be
described in greater detall below with reference to the
embodiments illustrated in the drawings wherein:
Figure 1 is a top view of an irrigation device designed
as a tank,
Figure 2 is a cross-section through the tank along line
II-II in Figure 1,
Figure 3 shows another irrigation device fashioned as a
tank,
Figure 4 is a cross-section through an irrigation device
designed as an insert for a box or a pot,
Figure 5 is a cross-section through another irrigation
device fashioned as an insert for a box or a pot,
Figure 6 shows an irrigation device for being embedded in
earth, and
Figure 7 is a top view of part of the device according to
Figure 6.
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
The irrigation device shown in Figures 1 and
2 consists of a tank 1 with a double-walled shell 2 and
a double-walled bottom 3. The outer wall 4 of the shell 2
is cylindrical; the inner wall 5 tapers conically toward
the bottom. The outer wall 6 of the bottom 3 is planar;
the inner wall 7 is curved downwards from the edge 8~
The reservoir space for the water, encompassed by the outer
and inner walls 4-7 of the shell and bottom 2 and 3 is de-
noted by 9. The shell 2 has an opening 12 that can besealed airtight by a rubber stopper 11 at its upper,
annular rim 10 for introduction and/or refilling of the
water into the reservoir space 9. The interior 14 of the
tank is filled with soil l5. Two passages 17, 18 are pro-
vided in the inner wall 7 of the bottom 3. The two pas-
sages are made of identical dimensions and are arranged
at equal spacings from the edge 8 of the bottom, i.e.
at the same level. The mutual spacing of the two passages
17, 18 is 1.5 cm and is dimensioned according to the formula
n 1 cm wherein n is the number of liters of the reservoir
volume. (In the embodiment, the storage space 9 has a
capacity of 1.5 liters.) The pasages 17, 18 taper
conically in the upward direction toward the inner chamber 14
and their inside diameter, i.e. the hole diameter at the
tapered end, is l mm.
A ring 20 is integrally formed at the underside
of the inner wall 7 of the bottom, this ring being seated
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tightly in an annular groove of the outer wall 6 of the
bottom. The portionof the outer wall 6 surrounded by the
ring 20 has a hole 21, and the portion of the inner wall 7
surrounded by the ring has a predetermined breaking point 22
formed by a notch-like annular groove for the breaking out
of a hole.
The tank 1 is composed of two pieces manufactured
from a synthetic resin by injection molding. The walls 4,
5, 7 with the rim 10 and the ring 20 constitute one piece;
the wall 6 with feet 23 integrally formed thereat consti-
tutes the other piece. The two pieces are joined to the
wall 6 by a splined connection 25 of the rims of walls 4
and 6, glued with an adhesive and thus sealed off, as well
as by a correspondingly sealed splined connection of the
lower rim of the ring 20.
The irrigation device constituted by the container 1
operates as follows: While water is filled in through the
opening 12, air is displaced from the reservoir 9 and
C ~ exits via the opening 12 and the passages 17, 18. After
the reservoir 9 is filled with water, the opening 12 is
sealed airtight by the stopper 11. At this point in time,
water will still be discharged from the passages 17, 18
until the suction pressure acting on the water column,
which suction pressure is produced due to the vacuum
formed above the water level 24 in the upper portion of
the reservoir 9, is of equal size as the weight of the
water column. Without any soil, the flow of water through
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the passages 17, 18 would now cease entirely. ~owever,
the soil adjoining the passages 17, 18 and wetted during
the filling step initially will still absorb some water by
capillary action so that the water column does not remain
in its equilibrium position (suction pressure = weight of
water), but rather is pulled downwardly to a small extent
against the suction pressure. The water column now has
the desire ~- under the effect of the suction pressure of
the vacuum -- to return into the equilibrium position.
This, though, cannot be accomplished at first because the
earth surrounding the passages 17, 18 has a high moisture
content and is therefore air-impermeable. Watering will
now remain interrupted until the plant has absorbed the
water from the soil, and the ground at one of the two
passages 17, 18, for example passage 17, has dried out to
such an extent that the air can pass through the soil 14
to this passage. The air is then taken in through the
passage 17 and rises as an air bubble into the upper part
C of the reservoir 9 whereby the vacuum is diminished. Water
will now exit from the other passage 18 to the extent
that air is taken in. The entrance of air into the passage
17 is stopped as soon as the water discharged from the
other passage 18 passes to the passage 17, and the earth
at that point has again become adequately moist for
sealing this passage. The earth is thus utilized, so to
speak, as a moisture-dependent sealing means, preventing
the entrance of air into the passages as soon as its
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moisture content has become adequately large. Consequently,
irrigation takes place which is automatically controlled
by the moisture content of the soil.
Based onthese realizations, found in the scope
of the present invention, regarding the mode of operation
of the irrigation device, the following result ensues:
The extent of irrigation depends essentially on the
spacing of the two pasages 17, 18: The larger the spacing,
the more intensive is the irrigation. For this reason,
the two passages 17, 18 are arranged, as set forth above,
in close proximity to each other, but still so far apart
that the usual foreign bodies contained in the soil, such
as stones or the like, cannot cover both passages; this is
so, because the device, for the above reasons, works only
if the earth adjoins directly at least one of the two
passages. If the spacing of the two passages 17, lB is
chosen to be too large, then excess watering results, and
there is the danger that the soil becomes boggy, and the
C , plants will not flourish. The spacing can be chosen to
be larger if the water volume and correspondingly the
amount of soil to be irrigated are very large. The
limit at which the danger of excess watering becomes
intolerably high lies approximately at a hole spacing
of n 3 cm, wherein n is the number of liters of the
reservoir volume.
Once the water stored in reservoir 9 has been
consumed, in the embodiment normally after about 2 months,
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refilling initially is neither required nor desirable
because the soil is still moist. It has been found that
the plants flourish substantially better when refilling is
postponed until the soil has been approximately dried out.
This can be recognized by the fact that the earth 15,
contracting during the drying out process~ detaches it-
self from the shell wall 5. Only once a pronounced annular
gap has been formed between the earth 15 and the wall 5
should the reservoir 9 be refilled with water.
( 10 It is essential in this connection that the
passages 17, 18 are arranged at a distance from the
shell wall 5 and, respectively, from the rim 8 in the
bottom wall 7, and that the latter is curved downwardly.
This ensures that even the dried-out clump of earth 15
located at a spacing from the shell wall 5 still is in
reliably firm contact with the passages 17, 18. This is
necessary so that the irrigation device, after water has
been replenished in the reservoir 9, again works reliably.
c Although water is dischrged from the pasages 17, 18 during
refilling, this quantity of water is not enough to
strongly moisten the clump of earth to such an extent that
it again expands up to the shell wall 5. Therefore, a
gap will remain between the soil and the shell wall 5,
and if the pasages are arranged in the latter, or
immediately at the rim of the bottom wall, then irriga-
tion is interrupted with finality as soon as the cor-
responding vacuum has been attained in the upper reservoir
portion.
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In case the device is set up in the open air,
for example if it is to be installed in a flower bed,
the predetermined breaking point 22 is broken through
by means of a tool introduced through the hole 21. In this
5 way, a drain hole is produced through which rainwater can
flow out of the interior 14 of the tank. Since the broken-
out drain hole is located at the lowermost point of the
inner wall 7 of the bottom, no rainwater can collect in the
interior of the tank. And because there is an interspace be-
( 10 tween the two drain holes of the walls 6 and 7, the soil 15
located in the interior 14 will definitely not directly
adjoin the soil locafed underneath the outer wall 6.
Consequently, the water exiting from the passages 17, 18
is prevented from being absorbed by the soil surrounding
15 the tank.
The ring 20 not only serves for separating the
reser~oir 9 from the drain holes but also acts as a spacer
means between the outer and inner walls 6 and 7 of the
C bottom. The ring prevents these walls from moving toward
20 each other in case of vibrations, thereby urging water
outwards through the passages 17, 18.
Another essential factor for the reliable
functioning of the device is that the air which has
passed through one of the passages 17, 18 into the
25 reservoir 9 will not remain in the zone of the passage
but rather will rise up. This is ensured by the curved
shape of the inner wall 7 of the bottom and, in case the
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tank is set up on an inclined support, by the circular
shape of the ring 20, to which rising air bubbles cannot
adhere.
The tank 30 illustrated in Figure 3 differs
from tank 1 as follows: Instead of a double-walled bottom,
this tank has a merely single-wall bottom 31 wherein the
lower rims of the outer and inner walls 32, 33 of the shell 34
are inserted. The shell 34 consists of porous clay to which
- has been applied, on the side facing away from the storage
10 chamber, a glazed, water- and air-impermeable layer 35.
Two zones 36, 37 have been left without glazing at the
lower rim of the inner wall 33. The pores of the clay wall
in these zones 36, 37 constitute the passages through which
the air can enter the reservoir and water can exit there-
15 from. The bottom 31 can consist of some other material,
or likewise of clay; in the latter case, the bottom must
also be glazed on its underside.
For the reasons mentioned in connection with
C the mode of operation of the tank 1, care must be taken
~0 in case of tank 30 that the earth does not dry out to such
an extent that it is detached from the inner wall 33 of
the shell 34 in the region of the zones 36, 37. In
order to avoid this drawback, the clay vessel 30 can, of
course, also be shaped in correspondence with the tank 1
25 so that the unglazed zones 36, 37 can be located in the
inner wall of the bottom.
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The irrigation device illustrated in Figure 4
denoted by 40 is fashioned as an insert for a flower
- box 41 or a flowerpot. The device consists of a con-
tainer 42, for example of a square shape, with an up-
5 wardly extending filling nipple 43 that can be tightly
sealed by a plug. Two capillary tubes 46, 47 are arranged
in the upper wall of the container 42 and extend into the
close proximity of the container bottom. Each capillary
tube 46, 47 is mounted at the top in a disk 48, 49, which
( 10 latter has an upwardly tapering passage 44, 45 adjoining
the bore for the capillary tube and is glued firmly onto
the upper container wall. The device 40 operates besically
in the same fashion as the tank 1 in that air enters the
reservoir of the container 42 through one of the two
15 capillary tubes 46, 47, and water exits through the re-
spectively other capillary tube.
In the version 50 of the insert 40 illustrated
in Figure 5, the capillary tubes are omitted, and the
C upper part of the container wall 51 has instead a recess 52
20 extending almost to the container bottom and having ap-
proximately the same shape as the inner walls 5 and 7 of the
shell and bottom 2 and 3 of the tank 1 and exhibiting in
its bottom 53 likewise two passages 54, 55 corresponding
to the passages 17 and 18. Suitably, this embodiment
25 likewise comprises, in correspondence with the tank 1,
a ring 20, a drain hole 21, and a predetermined breaking
point 22 so that rainwater can be drained from the recess
52 of the device set up in the open air.
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The irrigation device 60 illustrated in
Figures 6 and 7 is intended for being embedded in the
soil, for example in a flower bed, a flower box, and the
like. It c~nsists of a tank 61, for example a cylindrical
tank, exhibiting at the top an opening which can be sealed
off in an airtight fashion by a plug and having a foot 62
at the bottom; on the topside of this foot, which is in-
wardly curved and gradually rises from the foot end to a
continuously increasing extent toward the vertical tank
wall, two passages 63, 64 are provided corresponding
to the passages 17 and 18 of the tank 1. Depending on the
amount of the earth to be irrigated, several devices 60
can be embedded in the soil at mutual spacings.
It is also possible to provide more than two
passages, especially in case of very large irrigation
installations. In order to avoid excess watering, care
must be taken also in this instance that all of the pas-
sages are in an area withmaximum dimensions of n 3 cm,
preferably n 1 cm, for example in a circular area with
maximally this diameter (n = number of liters of reservoir
volume).
Since it is necessary for the functioning of
the irrigation device that at least one of the passages
is not segregated from the soil by a stone and the like
or by a cavity, an absorbent material can be arranged at
the passages,this material, in turn, directly adjoining
the soil. For example, at least one of the.passages 17, 18
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of the tank 1 can be covered by a piece of felt or another
absorbent and/or porous material, the dimensions of the
la~ter being such that a foreign body present in the
soil can cover only a partial area of the material, thus
en~uring a reliable communication of the soil with the
absorbent material. However, it has been found that there-
by irrigation takes place more quickly, and the danger of
excess watering and thus bogginess of the soil arises.
Therefore, this solution is suited practically only
( 10 for the device 60 to be embedded, for example, in the open
air into the ground.
The irrigation device can also be utilized for
irrigation of cultivated beds in nurseries etc. For this
purpose, the device can comprise a water tank, a pipeline
network being connected to the underside of this tank.
The passages in this arrangement are provided in the
jackets of the pipes; the free ends of relatively large
pipes are here to be sealed except for possible passages.
In order to introduce the water, the water tank can com-
pxise a connecting nipple for a waterline, which nipplecan be closed by a blocking element. At the top in the
tank wall, a check valve can be located through which the
air escapes from the tank while water is being filled in.
