Note: Descriptions are shown in the official language in which they were submitted.
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WEED WIPER
This invention is in the field of agricultural equipment, and
in particular such equipment for applying liquid herbicides.
BACKGROUND
In agriculture, liquid chemical solutions, such as herbicides
and pesticides, are typically applied to growing crops by
spraying on the crop. For herbicides, this requires that the
herbicide be selective such that the crop is not injured, but
the weeds are killed. Such selective herbicides are generally
more expensive than non-selective herbicides, such as
glyphosate, which. kill most plants including most weeds and
most crops. Also when spraying, any herbicide that contacts
crop plants instead of weeds is wasted at best, and often as
well damages the crop somewhat.
To overcome these problems, it is also known to use a rope
wick applicator to apply a non-selective herbicide only to the
weed~~, with no crop contact. The absorbent rope wick is
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soaked with herbicide and passes above the crop plants, coming
into contact with weeds that are taller than the crop. During
contact with the wet rope wick, herbicide is wiped off the
wick by the weed. Thus herbicide is applied only to the
talla_r weeds, and not on the crop. Much less herbicide is
used as well, since herbicide is only applied to the weeds,
not the crop. Stronger chemical solutions are generally used,
requ=firing less water to apply a given amount of chemical..
Commonly, presently known applicators work by a wick action.
One or both ends. of a section of absorbent rope wick are
located in a reservoir of liquid herbicide. The rope wick
draws liquid herbicide from the reservoir and becomes wet with
the liquid such that when the rope wick comes in contact with
a weed, liquid herbicide is wiped onto the weed. Typically
short. sections of rope wick are positioned along a hollow pipe
which acts as the reservoir for the liquid herbicide. The
pipe reservoir extends along the full width of coverage of the
applicator, and different sections generally must be filled
separately in wider applicators. Liquid capacity is limited
by the size of the pipe.
With present wick applicators, some time is required for the
wicks to become wetted once liquid chemical is poured into the
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reservoir. In order to increase the rate of flow of herbicide
through the rope wick, as may be required where weeds are
thick and liquid is being drawn off the wick more quickly, it
is necessary to stop the applicator and to rotate the pipe
reservoir so that. the wicks are lower and gravity aids the
wick action in drawing liquid into the wick. No other control
is generally provided, and rotating the pipe provides only a
limited range of rates. It may be necessary to slow the rate
of travel where high rates are required.
Examples of rope wick applicators are disclosed in United
States Patent Number 4,219,964 to Dale, and in United States
Patent Number 4,328,640 to Revelle.
STJ1~~ARY OF THE INVENTION
It i:~ an object of the present invention to provide a weed
wiping apparatus f:or wiping liquid chemical solutions, such as
herbicides, onto plants where the amount of liquid available
for wiping onto the plants can be conveniently varied by
varying the pressure of a pressurized liquid supply.
It is a further object of the present invention to provide
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such an apparatus which can be mounted as a kit on
conventional agricultural sprayers, thereby providing an
economical weed wiping apparatus with a large liquid chemical
reservoir.
The invention in one aspect provides an apparatus adapted for
movement along the ground in a direction of travel for
applying agricultural liquid chemical to plants by contact.
The apparatus comprises a liquid chemical reservoir and a
porous conduit extending lateral to the direction of travel of
the apparatus and located at a vertical height above the
ground. The porous conduit includes a conduit wall operative
to allow liquid chemical under pressure in an interior of the
porous conduit to pass through the conduit wall to an exterior
of the porous conduit. An absorbent wiper covers the exterior
of the porous conduit such that liquid chemical passing
through the conduit wall is absorbed by the wiper and the
wiper becomes wet such that contact of the wiper with a plant
results in transfer of liquid chemical onto the plant. A pump
is operatively connected to the reservoir to draw liquid
chemical therefrom and deliver same at a pressure to an
interior of the porous conduit and through the conduit wall of
the porous conduit to an exterior thereof to be absorbed by
the wiper. A control is operable to adjust the liquid
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chemical pressure in the interior of t:he porous conduit from
zero to a flow pressure.
The porous hose used is conventional soaker hose that is used
for garden irrigation purposes. The amount of liquid passing
through the wall of the hose increases generally as the
pressure inside the hose increases. When the pressure inside
the hose is zero, the hose retains the liquid, although liquid
may drip very sT_owly through the wall of the hose over a
period of time. For practical purposes, the liquid is
retained so that 'very little drip occurs when the apparatus is
idle.
In a second aspect, the invention provides a weed wiper kit
for attachment to a conventional agricultural ground sprayer.
The conventional sprayer comprises a liquid chemical
reservoir, a pump operatively connected to the reservoir to
draw liquid chemical from the reservoir and deliver same from
a pump output at a pressure to a spray boom. The spray boom
extends substantially perpendicular to a direction of travel
of the sprayer and is located at a vertical height above the
ground. A control is operative to turn the pump on and off.
The kit comprises a porous conduit deta.chably mountable below
the spray boom so as to extend substantially along a length of
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the boom. The full length of the boom may be conveniently
used to provide a wide wiper allowing for fewer passes to
cover a field. The porous conduit and absorbent wiper are
conveniently attached by straps, brackets or the like to the
spray boom. Fittings are attached to the sprayer to direct
liquid chemical f=rom the pump output to the interior of the
porous conduit instead of to the conventional spray boom. The
controls on a conventional sprayer are not normally able to
reduce the volume of liquid delivered by the pump to the low
levels desired for the porous hose, with the result that the
pressure in the porous hose can not be properly regulated
thereby. A further control may be required to adjust the
liquid chemical pressure in the interior of the porous conduit
from zero to a flow pressure.
DESCRIPTION OF THE DRATnIINGS
Whiles the invention is claimed in the concluding portions
hereof, preferred embodiments are provided in the accompanying
detailed description which may be best understood in
conjunction with t:he accompanying diagrams where like parts in
each of the several diagrams are labeled with like numbers,
and where:
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Fig. 1 is a front view of an embodiment of the invention;
Fig. 2 is a cross-sectional view along II - II' in Fig.
1;
Fig. 3 is a schematic top view of the embodiment of Fig.
1;
Fig. 4 is a.n enlarged cross section of a weed wiping
assembly.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS:
Fig. 1 illustrates an apparatus 1 of the invention for
applying agricultural liquid chemical to plants by contact.
The apparatus 1 is adapted for movement along the ground in a
direction of travel T. In the illustrated embodiment the
apparatus 1 is attached to a conventional agricultural ground
sprayer 2 comprising a liquid chemical reservoir 3, a pump 4
operatively connected to the reservoir 3 to draw liquid
chemical 5 from the reservoir 3 and deliver same from a pump
output 6 at a pressure to a spray boom 7 extending
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substantially perpendicular to the direction of travel T of
the :prayer 1 and located at a vertical height HB above the
ground 8. The pump 4 is conventianally operated by hydraulic
pressure or a power-take-off shaft from a towing tractor, and
includes a conven.tiona:l control to turn the pump on and off.
The illustrated c=mbodiment is a tow behind sprayer however
self--propelled sprayers are also well known and the invention
could be practiced on these as well.
The apparatus 1 comprises a weed wiping assembly 9 extending
lateral to the direction of travel T of the apparatus 1 and
located at a vertical height H4~1 above the ground, below the
spray boom 7. 'The weed wiping assembly 9 is attached by
straps 21 and bucl~:les 22 to the spray boom 7. The weed wiping
assembly 9 comprises a porous conduit 10 including a conduit
wall 10w operative to allow liquid chemical 5 under pressure
in the interior of the porous conduit 10 to pass through the
conduit wall 10w to the exterior of the porous conduit 10.
The action of the porous conduit 10 is illustrated in Fig. 4.
The porous conduit 10 used in the illustrated embodiment is a
conventional garden soaker hose available from Colorlite
Plastics Canada of Mississauga, Ontario as the
"IrrigatorSoakerTM". The passage of liquid chemical 5 through
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the conduit wall 10 is generally proportional to the pressure
of the liquid chemical 5 inside the porous conduit 10, in that
the greater the pressure, the greater the flow through the
conduit wall 10w. When the pressure of the liquid chemical
drop: to zero, the flow substantially stops, and the conduit
wall 10w is operative to substantia=Lly retain the liquid
chemical 5 inside the porous conduit 5. The liquid chemical 5
may leak out over an extended period of time however for the
purposes of the apparatus 1 the flow is essentially stopped.
An absorbent wiper 11 covers the exterior of the porous
conduit 10 such 'that liquid chemical 5 passing through the
conduit wall 10 is absorbed by the wiper 11 and the wiper 11
becomes wet such that contact of an exterior of the wiper 11
with a plant, su~~h as the weed 12, results in transfer of
liquid chemical 5 onto the weed 12, as illustrated in Fig. 2.
The wiper 11 comprises a foam material 13 adjacent to the
porous conduit 10,, and further comprises a fabric material 14
covering the foam material 13, with the wiper components sewn
together along th.e top edge as illustrated in Fig. 4. The
foam material 13 provides ample absorbency to retain a good
supply of liquid chemical 5 in the wiper 11, while the fabric
material 13 is abrasion resistant material such as carpet or
the like.
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Conventional fittings can be used to adapt the apparatus to
the conventional sprayer 2 to direct liquid chemical 5 from
the pump output 6 to the interior of the porous conduit 10.
In the illustrated embodiment, a diverter valve 15 is operable
to selectively direct liquid chemical 5 to the boom 7 or to
the :interior of the porous conduit 10 and through the conduit
wall 10 to be absorbed by the foam and fabric material 13, 14
of the wiper 11.
The controls on a conventional sprayer 2 are not normally able
to reduce the volume of liquid chemical 5 delivered by the
pump 4 to the low levels desired for the porous hose 10, with
the result that the pressure in the porous hose 10 cannot be
properly regulated thereby. A further :liquid chemical control
is provided to adjust the pressure of the liquid chemical 5 in
the :interior of the porous conduit 10 from zero to a flow
pressure. The liquid chemical control can conveniently and
economically be a valve 16 which essentially restricts the
volume of flow to the porous conduit 10 to approximately the
volume desired to pass through the conduit wall to the wiper
11, thereby achieving the pressure control indirectly. It may
be advisable to supply a filter before the valve 16 if
particles may be present in the liquid that would interfere
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with the operation of the valve 16. More elaborate controls
that directly controlled the pressure would also be
sati:~factory.
In operation the operator adjusts the valve 16 to allow a
small volume of flow to the porous conduit 10. The liauid
chemical passes through the conduit wall 10w and soaks the
foam and fabric material 13, 14. When these are soaked, the
operator may begin traveling in a fie:Ld to apply the liquid
chemical 5 to tall weeds 12. The height HW of the wiper 11
above the ground 8 is adjusted using the conventional boom
height control 17 of the sprayer 2 such that same is above the
crop plants 19, but is low enough to contact weeds 12 which
are taller than the crop plants 19. The liquid chemical 5 is
wiped onto the weed 12 from the fabric material 14 of the
wiper 11, and may run down the weed 12 as illustrated in Fig.
2. The operator will find the proper flow rate for a given
condition by experimentation. A valve 16 with a fine
adjustment, and with markings to indicate the degree of
opening of the valve is preferred.
In operation the flow of liquid chemical 5 through the conduit
wall 10w to the wiper 11 will be substantially constant.
Where weeds 12 are thicker, and more liquid chemical 5 is
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being wiped from the fabric material 14, the liquid chemical 5
retained in the foam material 13 is soaked up by the fabric
material 14, and the foam material 13 dries up somewhat, as
the liquid chemical 5 is being wiped off the wiper 11 faster
than the liquid chemical 5 is flowing through the conduit wall
10w. When the weeds 12 thin out, the flow of liquid chemical
will exceed the amount being wiped off, and the foam
material 14 will be recharged. The operator will adjust the
valve 16 and the :flow rate for a given field or condition such
that the average rate of wiping is substantially equal to the
flow through the conduit wall 10w.
The apparatus could be manufactured as a unit, or could
conveniently and economically be manufactured as a kit,
containing the required fittings, conveniently including a
diverter valve 15, a weed wiping assembly 9, with attached
straps and bucklers 21, 22, and a :liquid chemical control such
as the valve 16.
The foregoing is considered as illustrative only of the
principles of the invention. Further, since numerous changes
and modifications will readily occur to those skilled in the
art, it is not desired to limit the invention to the exact
construction and operation shown and described, and
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acr_ordingly, all such suitable changes or modifications in
structure or operation which may be resorted to are intended
to fall within the scope of the claimed invention.
