Note: Descriptions are shown in the official language in which they were submitted.
CA 02298893 2000-02-15
FLOW CONTROL SYSTEM FOR SPRAYER NOZZLES
FIELD OF INVENTION
This invention relates to sprayers and in particular to a flow control system
for sprayer
nozzles.
BACKGROUND OF THE INVENTION
A typical spraying nozzle comprises a nozzle body, a diaphragm check valve, a
nozzle
body screen or filter, a nozzle tip and a nozzle cap. The diaphragm check
valve shuts off the
nozzle at a predetermined pressure. In the case of an agricultural field
sprayer, a plurality of
nozzles are usually mounted on a spraying bar, towed in the field by a
tractor. Alternately, the
sprayer could be self propelled. The number of the nozzles on the spraying bar
is proportional
to the width of the spraying bar.
Various systems have been proposed in the past for reducing or shutting off
the fluid flow
to a sprayer nozzle body.
Several prior art systems employ solenoid coils with a plunger that are either
integral at
the nozzle cap in non-standard nozzle bodies and can not be retrofitted to
existing sprayer
fittings, or are made to adapt to standard nozzle bodies at their check valve
location requiring
removal of the check and in such location are not filtered by the nozzle body
filter. In operation,
the coil is energized by a nozzle control system to open the plunger valve.
For agricultural sprayers, the control coils require at least 6 watts per
nozzle, hence a
large amount of power is drawn from a tractor on larger width units. In most
cases, an extra
power source is required on the tractor.
In the prior art, the coils are normally in a position with the plunger
blocking the fluid
path (position which is hereinafter called closed) and must be energized to
activate the plunger
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CA 02298893 2000-02-15
to displace it to a position allowing fluid flow (position which is
hereinafter called open).
Therefore if a coil fails or power to the coil is disconnected, the fluid flow
from the nozzle body
to the tip is affected and there will be a down time in spraying, required to
replace or repair the
defective coil.
On many of these prior art systems, the nozzle screen is positioned after the
solenoid
plunger, thus there is an increased chance that the plunger will become
plugged with particles.
Additionally, most of the current nozzle control systems, lack the standard
diaphragm
check valve, which provides shut off to the nozzle at a pre-determined
pressure. Therefore, the
flow through the nozzles must be controlled solely by the solenoid coils.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved flow control
system for a
sprayer nozzle assembly.
Another object of the present invention is to provide a flow control system
for sprayer
nozzles on agricultural machines, which is economical in terms of power
consumption.
Still another object of the invention is to provide a flow control system for
sprayer
nozzles that is easily adaptable to nozzle assemblies available on the market.
According to the present invention, there is provided a flow control system
comprising:
a spray nozzle comprising a fluid passage, the fluid passage comprising a
fluid spray outlet;
a control valve mounted on the spray nozzle, the control valve comprising a
actuator and a flow
impeding device, whereby activation of the actuator causes the flow impeding
device to move
into the fluid passage of the spray nozzle thereby impeding fluid flow through
the spray nozzle,
the actuator being adapted for selective activation upon receipt of control
signals from the control
unit.
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According to the present invention, there is further provided a flow control
system
comprising: a spray nozzle comprising a nozzle body, the nozzle body
comprising a fluid spray
outlet and a nozzle check valve; a fluid passage defined by a wall between the
nozzle check valve
and the fluid spray outlet; and a control valve mounted on the nozzle body and
being switchable
between a rest state wherein fluid is permitted to flow along the fluid
passage, and an energized
state wherein fluid flow is restricted through the fluid passage, the control
valve being adapted
to receive the control signals from the control unit for switching the control
valve from the rest
state to the energized state.
According to the present invention, there is further provided a control valve
adapted to
retrofit on a flow control system, the flow control system comprising: a
nozzle body comprising
a fluid spray outlet and a nozzle check valve; a fluid passage defined by a
wall between the
nozzle check valve and the fluid spray outlet; a nozzle screen mounted on the
nozzle body; and
the control valve mounted on the nozzle body between the nozzle screen and
fluid spray outlet
such that the nozzle screen is upstream and the fluid spray outlet is
downstream from the control
valve along the fluid passage.
The present invention relates to a flow control system for sprayer nozzles.
The control
system comprises a solenoid coil and a solenoid plunger. Alternatively, the
solenoid plunger
could be replaced with a valve, such as a spool valve. The solenoid plunger
can slide into an
adapter body, substantially perpendicular to the direction of fluid flow. In
reducing the fluid flow
through the nozzle, the plunger is moved to block, partially or completely, an
orifice in the path
of the fluid flow, within the adapter. The plunger movement is achieved
through the energization
of the solenoid coil, with signals sent by a controller. The design is such
that the nozzle is fully
open when the solenoid coil is not energized.
The orifice in the adapter may be manufactured to a specific size which allows
reduced
power consumption to shut off or reduce flow through the nozzle. This feature
is especially
useful when the system is used on agricultural sprayers with many nozzles.
Furthermore, the
orifice may be sized to provide unrestricted fluid flow when fully open.
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The adapter may be inserted between the nozzle spray screen and the nozzle
tip, for
spraying iiozzles that have the nozzle tip and the nozzle spray cap as
separate pieces, or it may
be inserted between the nozzle spray screen and a one piece nozzle spray tip-
cap, for spraying
nozzles provided with such a piece.
In operation, pressurized fluid is supplied to the nozzle. A diaphragm check
valve will
not open until a predetermined pressure is reached. When the fluid pressure
exceeds the
predetermined pressure, the diaphragm check valve opens, allowing fluid to
flow through the
nozzle body screen, through the adapter body, to the nozzle tip.
By means of the controller, each nozzle from a plurality of nozzles on a
spraying bar can
be individually controlled.
In one aspect of the invention, the flow control system can be used with
agricultural
sprayers with sensing equipment, such as cameras that may determine the green
condition of the
foliage being sprayed. According to the determined condition, the controller
would regulate the
flow through the nozzles in the corresponding area of the field.
Advantageously, the spray control system of the invention can be adapted to
off-shelf
nozzle assemblies and can control individually each nozzle.
Other advantages, objects and features of the present invention will be
readily apparent
to those skilled in the art from a review of the following detailed
description of preferred
embodiments in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The embodiments of the invention will now be described with reference to the
accompanying drawings, in which:
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Figure 1 is a block diagram of a sprayer system in accordance with an
embodiment of the
invention;
Figure 2 is an exploded view of a nozzle flow control assembly in accordance
with an
embodiment of the invention;
Figure 3A is a cross-sectional view of a nozzle flow control system usinQ a
through
adapter and a pull-to-close solenoid, in accordance with one aspect of the
invention; and
Figure 3B is a cross-sectional view of a nozzle flow control system using a
tee adapter
and a push-to-close solenoid, in accordance with another aspect of the
invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to Figure 1, a block diagram of a sprayer system 1 in accordance
with an
embodiment of the present invention is illustrated. The sprayer system
comprises a controller or
control unit 2 for monitoring a plurality of nozzles 4 mounted on a spraying
bar or spraying
pipe 6. A plurality of remote/sensor 8 units can be interposed between the
controller 2 and the
nozzles 4 on the spraying bar 6. The operation of the sprayer system 1
depicted here is described
later on.
Referrina now to Figure 2, the nozzle flow control assembly 10 of the present
invention
is shown as being adapted for attachment to an existing nozzle 4. A nozzle 4
typically comprises a nozzle body 12, a diaphragm check valve or nozzle check
valve 14, a
nozzle body screen or filter 16, a nozzle tip or tluid outlet 18 and a nozzle
spray tip cap 20., all
ali-ned along a longitudinal axis A-A. Axis A-A will be referred to as the
nozzle axis for the
purpose of this document. Fluid flows from nozzle body 12 to tip 18 as shown
by arrow B.
The nozzle flow control assembly 10 is placed between the nozzle body screen
16 and
nozzle tip 18, and, as the name indicates. it serves to control the fluid t1ow
through the nozzte 4.
In the case when the nozzle tip 18 and the nozzle cap 20 are manufactured as
one piece. the
CA 02298893 2000-02-15
nozzle flow control assembly 10 is placed between the nozzle body screen 16
and the one piece
nozzle spray tip cap. The nozzle flow control assembly 10 comprises an nozzle
adapter 22. The
nozzle adapter 22 has to support a solenoid coil 24 and/or a flow impeding
device 26, 28. It
should be noted that the flow impeding device 26, 28 is ideally a solenoid
plunger, but could also
be a valve, such as a spool valve. The adapter 21, 22 can be any type of
adapter such as a tee
adapter as shown in Figure 3B or a through adapter as shown in Figure 3A. The
solenoid could
also be replaced with any other actuating means, such as a motor or hydraulic.
Referring also to Figures 3A and 3B, the adapter has an orifice 34, 35, for
sealing off the
fluid flow B to the nozzle tip. The orifice 34, 35 is provided within the wall
at the level in the
detour of the nozzle adapter and has a cross-sectional plane at an angle to
the nozzle axis A-A.
Preferably, this angle is 90 . The orifice 34, 35 is manufactured to a
specific size which allows
reduced power consumption to shut off flow to the nozzle, as it will be
further described . The
size of the orifice is such that it provides unrestricted fluid flow when
fully open, so that it has
no effect on fluid flow typical to required operation.
The solenoid coi123, 24 is placed into the adapter body 21, 22 transversal to
the cross-
sectional plane of the orifice 34, 35. A`push to close' type solenoid 23 is
suited for a tee
adapter 21 (Figure 3B) and a`pull to close' type solenoid 24 is suited for a
through adapter 22
(Figure 3A). The plunger 25, 26, 28 is adapted to slide along the axis of the
solenoid coil 23, 24
in response to energization (activation) of the solenoid coi123, 24.
Figure 3A shows a cross-section of the nozzle flow control assembly using a
through type
adapter 22 and a pull-to-close solenoid 24, 26 and 28. As depicted in Figs. 2
and 3A, in the case
of a through type adapter 22, the plunger comprises two pieces, piece 26 and
piece 28, each
adapted to fit inside the adapter 22, along an axis C-C normal to the cross-
sectional plane of the
orifice 34. Piece 26 of the plunger is adapted to slide with its end b into
open end c of the
adapter 22. Piece 28 of the plunger is adapted to slide with its end h through
the open end d of
the adapter 22, and further through the orifice 34. Piece 28 of the plunger
has an enlarged cross-
section region 29 at its end i. When the solenoid coi124 is activated, piece
26 of the plunger pulls
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piece 28 through the orifice in the adapter body 22. The enlarged cross-
section region 29 allows
piece 28 slide only partially through the orifice 34, thus shutting off the
fluid flow B.
In order to block the orifice 34 efficiently, the pulling force created by
energizing the
solenoid coi124 has to overcome the force exerted by the fluid flowing onto
the enlarged cross-
section region 29 at end i of piece 28. For an efficient design, the power
applied to the solenoid
coil 24 must be minimal, thus the pulling force must be minimal. Therefore, in
a preferred
embodiment, the force exerted by the fluid onto the enlarged cross-section
region 29 is
minimized. The force exerted by the fluid flow onto the enlarged cross-section
region 29, is
directly proportional with the pressure of the fluid and to the surface area
of this region. As the
pressure within the fluid is predetermined, the force is minimized by
minimizing the total surface
area of the enlarged cross-section region 29, onto which the fluid flows.
Therefore, the remaining
of piece 28 must have a cross-section small enough to allow it to slide
through the orifice 34, but
large enough so as to allow only a very small surface area of the enlarged
cross-section region 29
to be in contact with the fluid, in the closed position. In turn, the size of
orifice 34 can be
manufactured to render reduced power consumption, according to the principles
described.
When the solenoid is no longer energized, the pressure exerted by the fluid
flowing onto
the enlarged cross-section region 29 of piece 28 pushes plunger 26, 28 open,
and fluid can flow
through the orifice 34.
A seal 32 is preferably mounted on the plunger at end i of piece 28. The
purpose of the
seal 32 is to seal against fluid flow through the orifice 34 in the adapter
body 22, in the closed
position.
In a preferred embodiment, end h of piece 28 is threaded externally, and end b
of piece
26 has an inner bore threaded so as to engage end h of piece 28.
Figure 3B shows a cross-section of the nozzle flow control assembly 10 using a
tee type
adapter 21 and a push-to-close solenoid 23. In this embodiment, the plunger 25
is adapted to slide
with end e into open end f of the adapter 21 along the axis C-C normal to the
cross-sectional
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plane of the orifice 35. End b of the plunger 25 has a cross-section larger
than the size of the
orifice 35. When the solenoid coil 23 is activated, the plunger 25 is forced
into the adapter 21,
causing seal 33 to seat against orifice 35, blocking the flow. For completely
closing the orifice
35, the force applied to push plunger 25 into blocking the orifice 35, must be
greater than the
force exerted by the fluid onto the end e of the plunger 25. The force exerted
by the fluid onto
end e of the plunger 25 is directly proportional to the surface area of the
end e plunger, contacted
by the fluid. In a fully closed position, this surface area is substantially
the same as the cross-
sectional area of the orifice 35. Thus, the amount of power required to fully
close the orifice 35
is directly proportional to the cross-sectional area of the orifice 35.
A seal 33 is mounted on the plunger 25 at end e. The purpose of the seal 33 is
to seal
against fluid flow through the orifice 35 in the adapter body 21, in the
closed position.
In general, a partially closed position is achieved if the signal applied to
the solenoid coil
is not fully energized. In such a case, the plunger will only be partially
closed to a position in
which the closing force is balanced with the fluid pressure acting on the
plunger. Hence, the
fluid flow through the orifice, and thus through the nozzle, is only reduced
but not completely
shut off.
The plunger size and seal type match up to the push or pull type solenoid.
An 0 ring 41 is preferably fitted between the solenoid coil and the plunger
for better
sealing.
In an alternative embodiment, a solenoid activated plunger can be used to open
or close
a flapper or a diaphragm blocking an orifice in the path of the fluid flow,
rather than pressing a
seal against that orifice.
Preferably, nozzle cap gaskets 27, 37 are inserted between the adapter and
each of the
nozzle body and the nozzle tip, respectively.
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For simplicity, the operation of the flow control system accordina to the
invention will
be described in the context of its application to an agricultural sprayer, but
it has to be
appreciated that the use of the invention can extend to any system where there
is a need to
provide flow control to a spraving nozzle.
In operation, pressurized fluid is stipplied to the nozzle body 12 through the
port 3. The
diapliragm check valve 14 will not open until a predetermined pressure, for
example 7 -10 psi,
is reached. When the fluid pressure exceeds the predetermined pressure, the
diaphragm check
valve 14 opens, allowing fluid to flow through the nozzle body screen 16, and
through the
adapter body 21, 22, to the nozzle tip 18. The fluid is then distributed onto
the foliage being
sprayed. By means of the controller 2, flow control can be provided
individually to each nozzle 4
and to a plurality of nozzles on the spraying bar 6.
Referring to Figures 1, 2 and 3A, the normally open orifice 34 allows fluid to
flow to the
nozzle tip 18 at all times unless the solenoid coil 24 is activated by the
controller 2 into closing
it, partially or fully, which reduces or stops the fluid flow to the nozzle 4.
The open and closed
states of a particular nozzle, as controlled by the controller 2, correspond
to a de-energized and
an energized state of the solenoid coil from the corresponding nozzle flow
control assembly,
respectively. In one embodiment. the control of the nozzles is achieved by
means of remote
sensors 8, each corresponding to a certain group of nozzles 4. The remote
sensors 8 sense the
condition of the foliage being sprayed in the area of the nozzles 4 that
correspond to them, and
send to the controller 2 signals indicating whether the amount of flow through
the corresponding
nozzles 4 must be increased or reduced.
Since the nozzles are normally in an rest state, power is drawn from.the
transport vehicle
(e.g. a tractor) only -vvhen a nozzle has to be closed, which entails
activating its solenoid coil.
Hence, the power consumption is proportional to the length of time the
solenoid coils must be
activated, thus closina the nozzles. Therefore, in the case of a field with
many weeds, the power
consumption will be smaller than in prior- art svstems in which control
solenoid coils of equal
size are activated to keep the nozzles open. In the present invention, because
of the normal,
deactivated. open state of the solenoid coils, if a coil fails or if the coil
is disconnected, the fluid
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flow from the nozzle body to the nozzle tip is not affected and the operator
can continue spraying
with no down time for replacing the coil.
Because the nozzle screen is placed before the solenoid plunger, the chances
of the
plunger becoming jammed from particles are reduced.
Turning now to Figure 1, the present invention can be used in conjunction with
sensors,
cameras and means providing in cab-monitoring of various conditions such as
green condition
of foliage, or of soil nutrient resources .
Through signals received from the remote sensors 8 or from cameras installed
close to
the nozzles, the controller recognizes the areas that do not require spraying
and stops fluid flow
to the nozzles corresponding to those areas. Similarly, the controller can
recognize areas that
require less spraying and allow a reduced fluid flow through the corresponding
nozzles.
Based on the logic built into it, the controller can decide what type of
signal to send to
each individual solenoid coil, controlling a particular nozzle. The controller
may send a fully
energized signal, a partially energized signal, a pulsed signal with a
specific duty cycle, or any
other signal.
Fully energized signals completely shut off the corresponding nozzles.
Partially energized
signals or signals pulsed at a specific duty cycle allow a reduced amount of
flow on
corresponding areas.
As shown in Figure 1, cameras or vision system sensors 8 are mounted ahead of
nozzles 4. For example, one camera or other remote sensor 8 controls a certain
number of
nozzles. In the embodiment presented in Figure 1, a remote sensor 8 controls
two adjacent
nozzles 4. As the sprayer is pulled through a field, the cameras 8, which are
directed at the
ground, look for green plants. In one aspect of the invention, on reaching an
operator set level
for the amount of green the camera must see, the camera sends a signal to
fully open the nozzle
controller, allowing a green area to be sprayed with chemical. If a camera
does not see a
CA 02298893 2000-02-15
sufficient amount of green according to the operator set level in a certain
area, a pulsed signal
is sent by the controller to apply a reduced application rate over that area.
The present system can be used with a monitor with a task controller connected
to a
Global Positioning System (GPS). In addition, the operator can input into the
controller a
herbicide prescription map, corresponding to the field being sprayed. By
recognizing its position
in the field, with the aid of the GPS system, and identifying the requirements
of the particular
area based on the provided prescription map, the controller would signal each
individual nozzle
to be open, closed, or active at a certain duty cycle.
Additionally, with the above described system, overlapping in spraying can be
greatly
reduced, so that any given area of the field is sprayed only once. The
controller would just have
to shut off the overlapping nozzles.
It will be understood by those skilled in the art that the controller can be
programmed to
determine the necessity for spraying based on a variety of conditions, to
control the solenoid
nozzles individually or in any combination, to send to the solenoid coils any
type of energizing
signals or other like functions.
Numerous modifications, variations and adaptations may be made to the
particular
embodiments of the invention described above without departing from the scope
of the invention,
which is defined in the claims.
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